WO2019111919A1 - Solid-state image capture element and method of manufacturing same - Google Patents

Solid-state image capture element and method of manufacturing same Download PDF

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Publication number
WO2019111919A1
WO2019111919A1 PCT/JP2018/044637 JP2018044637W WO2019111919A1 WO 2019111919 A1 WO2019111919 A1 WO 2019111919A1 JP 2018044637 W JP2018044637 W JP 2018044637W WO 2019111919 A1 WO2019111919 A1 WO 2019111919A1
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Prior art keywords
color
color filter
layer
solid
transparent conductive
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PCT/JP2018/044637
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French (fr)
Japanese (ja)
Inventor
高橋　聡
知宏 井本
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凸版印刷株式会社
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Priority to JP2019558237A priority Critical patent/JP7508779B2/en
Publication of WO2019111919A1 publication Critical patent/WO2019111919A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/10—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths
    • H04N23/12—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths with one sensor only

Definitions

  • the present invention relates to a technology relating to a solid-state imaging device using photoelectric conversion devices such as CCDs and CMOS.
  • Solid-state imaging devices such as CCDs (charge-coupled devices) and CMOS (complementary metal oxide semiconductors) mounted on digital cameras etc. have recently been increased in the number of pixels and miniaturized, and the pixels are particularly fine. In the pixel size, the pixel size is below 1.4 ⁇ m ⁇ 1.4 ⁇ m.
  • the solid-state imaging device has a photoelectric conversion device and a pair of color filter patterns to achieve colorization.
  • region (opening part) which the photoelectric conversion element of a solid-state image sensor contributes to photoelectric conversion depends on the size and the number of pixels of a solid-state image sensor. The opening is limited to about 20 to 50% of the total area of the solid-state imaging device. Since a small opening directly leads to a decrease in the sensitivity of the photoelectric conversion element, it is general in a solid-state imaging element to form a microlens for collecting light on the photoelectric conversion element in order to compensate for the reduction in sensitivity.
  • the opening of the photoelectric conversion element can be 50% or more of the entire area of the solid-state imaging element.
  • Patent Document 1 As a method of forming such a color filter pattern on a solid-state imaging device, a method of forming a pattern by a photolithography process as in Patent Document 1 is generally used.
  • Patent Document 2 describes a method of forming all the color filter patterns by dry etching.
  • the aspect ratio of the color filter pattern increases.
  • the color filter of the portion to be originally removed (the non effective portion of the pixel) is not completely removed and becomes a residue and adversely affects the pixels of other colors. It will exert.
  • a method such as extending the development time is performed to remove the residue, there is also a problem that the hardened necessary pixels are peeled off.
  • the thickness of the color filter In addition, in order to obtain satisfactory spectral characteristics, the thickness of the color filter must be increased. However, when the film thickness of the color filter is increased, the resolution tends to be reduced, for example, the corners of the color filter pattern are rounded as the miniaturization of the pixels progresses. In order to increase the film thickness of the color filter pattern and to obtain spectral characteristics, it is necessary to increase the pigment concentration contained in the color filter pattern material. However, when the pigment concentration contained in the color filter pattern material is increased, the light necessary for the photocuring reaction does not reach the bottom of the color filter pattern layer, and the curing of the color filter layer becomes insufficient. For this reason, there is a problem that the layer of the color filter is peeled off in the developing step in photolithography to generate a pixel defect.
  • the throughput is reduced by increasing the exposure amount at the time of curing in order to sufficiently photocure the layer of the color filter.
  • the film thickness of the color filter pattern affects not only the problem in the manufacturing process but also the characteristics as a solid-state imaging device.
  • the film thickness of the color filter pattern is large, light incident from an oblique direction may be split by the specific color filter and then may enter the adjacent other color filter pattern portion and photoelectric conversion element. In this case, there arises a problem that color mixing occurs.
  • the problem of color mixture becomes significant as the pixel size of the color filter pattern decreases and the aspect ratio between the pixel size and the film thickness increases.
  • the problem of color mixing of incident light is remarkable even when the distance between the color filter pattern and the photoelectric conversion element is increased by forming a material such as a planarization layer on a substrate on which the photoelectric conversion element is formed. It occurs. For this reason, it is important to reduce the thickness of the color filter pattern and the planarizing layer formed therebelow.
  • the size of the partition required is several hundred nm, more preferably about 200 nm or less in width, and high definition of pixel size is achieved until one pixel size becomes about 1 ⁇ m. Is advancing. For this reason, if the light shielding performance capable of suppressing color mixing can be satisfied, a width (dimension) of 100 nm or less is desirable. It is difficult to form partition walls of this size by photolithography using a BM.
  • Patent Document 2 describes that a color filter pattern is formed by dry etching that can be patterned without containing a photosensitive component so that the pigment concentration in the color filter material can be improved. These techniques of using dry etching make it possible to improve the pigment concentration, and it is possible to produce a color filter pattern that can obtain sufficient spectral characteristics even when the film is thinned.
  • the present invention has been made in view of the above-described points, and it is an object of the present invention to provide a solid-state imaging device having high definition and high sensitivity by suppressing color mixing, reducing plasma damage.
  • a solid-state imaging device includes a semiconductor substrate on which a plurality of photoelectric conversion devices are two-dimensionally arranged, and a color filter formed on the semiconductor substrate and corresponding to the plurality of photoelectric conversion devices. Providing a color filter layer two-dimensionally arranged in a predetermined regular pattern, and a transparent conductive layer disposed between the color filter of the first color selected from the plurality of colors and the semiconductor substrate.
  • the transparent conductive layer contains at least one selected from silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine.
  • the compound may be formed in a single layer or multiple layers.
  • the transparent conductive layer and the color filter of the first color have an etching rate of the transparent conductive layer as T and an etching rate of the color filter of the first color as G, fluorine, oxygen, hydrogen, sulfur
  • the material configuration may satisfy the following formula (2). 3 ⁇ G / T (2)
  • the partition wall may contain at least one selected from zinc, copper, nickel, silicon, carbon, oxygen, hydrogen, nitrogen, bromine, chlorine, indium and tin.
  • the film thickness of the first color filter is A [nm]
  • the film thickness of the transparent conductive layer is B [nm]
  • the film thickness of color filters of colors other than the first color is C [nm]
  • the visible light transmittance of the transparent conductive layer is D [%]
  • the dimension of the partition is E [nm]
  • the following formulas (3) to (7) may be satisfied. 200 [nm] ⁇ A ⁇ 700 [nm] (3) 0 [nm] ⁇ B ⁇ 200 [nm] (4)
  • a transparent resin layer may be further provided between the transparent conductive layer and the color filter of the first color.
  • a transparent resin layer may be further provided between the transparent conductive layer and the semiconductor substrate.
  • the transparent resin layer may contain at least one selected from silicon, carbon, oxygen, and hydrogen.
  • the first color filter may contain a thermosetting resin.
  • the color filter of the first color may contain a thermosetting resin and a photocurable resin, and the content of the thermosetting resin may be larger than the content of the photocurable resin.
  • the color filter of the first color may contain a photocurable resin.
  • the color filter of the first color may have a concentration of the pigment as the colorant of 50% by mass or more.
  • a microlens having a two-dimensional arrangement corresponding to each of the photoelectric conversion elements is provided on the color filter layer, and the height from the lens top to the lens bottom of the microlens ranges from 300 nm to 800 nm. It may be
  • the area occupied by the color filter of the first color may be the largest.
  • a transparent conductive layer is formed on a semiconductor substrate in which a plurality of photoelectric conversion devices are two-dimensionally arranged, and a first color color filter is formed on the transparent conductive layer.
  • the coating solution is applied and cured to form the transparent conductive layer and the color filter layer of the first color in this order, and then the color filter layer of the first color other than the arrangement position of the color filter of the first color
  • the color of the first color in the first step of patterning the first color filter by removing the portion by dry etching and the first step of patterning the first color filter;
  • Color color filters of other colors characterized in that it comprises a third step of forming and patterning by photolithography, a.
  • a transparent conductive layer is formed on a semiconductor substrate in which a plurality of photoelectric conversion devices are two-dimensionally arranged, and a transparent resin layer is formed on the transparent conductive layer.
  • a coating solution for a first color filter is applied and cured to form a transparent conductive layer, a transparent resin layer, and a first color filter layer in this order, and then the arrangement of the first color filter
  • the color filter layer portion of the first color other than the position and the transparent resin layer located under the first color filter layer portion are removed by dry etching to pattern the first color color filter
  • the transparent resin layer positioned under the color filter layer of the first color and the color filter layer portion to be removed is used.
  • Dry etch Forming a color filter layer, a transparent resin layer, and a by-product of a dry etching gas, which are generated during printing, as partition walls on the side walls of the color filter of the first color; And a third step of forming and patterning a color filter of a color other than one by photolithography.
  • the heating temperature at the time of curing of the color filter of the first color may be 170 ° C. or more and 270 ° C. or less.
  • color mixing can be suppressed by the thinning of the color filters and the partitions between the color filters, and there is no plasma damage due to dry etching and high definition in which all the color filters arranged in pattern have high sensitivity. It becomes possible to provide a solid-state imaging device.
  • FIG. 2 is a partial plan view of a color filter array of a solid-state imaging device according to a first embodiment of the present invention. It is a manufacturing-process sectional view of the solid-state image sensor concerning a 1st embodiment of the present invention, and is a figure showing from a transparent conductive layer formation process to a color filter heat-hardening process of the 1st color.
  • FIG. 6A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from a photosensitive resin material application process to a developing process of a first color filter layer; FIG.
  • FIG. 6A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from dry etching a part of the first color filter layer to an etching mask removing process
  • FIG. 7A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from a second color filter application process to heat curing of the second color filter
  • FIG. 7A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from a third color filter application process to a heat curing process for the third color filter.
  • FIG. 5A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, and is a view showing a planarizing layer forming process and a microlens forming process.
  • FIG. 5A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process of forming a planarizing layer to a process of forming a microlens matrix layer;
  • FIG. 5A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a lens matrix forming process to a lens transferring process. It is a fragmentary sectional view of the solid-state image sensor concerning a 2nd embodiment of the present invention.
  • FIG. 7A is a manufacturing process sectional view of the solid-state imaging device according to the second embodiment of the present invention, showing a process from dry etching a part of the first color filter layer to an etching mask removing process; It is a fragmentary sectional view of the solid-state image sensor concerning a 3rd embodiment of the present invention. It is manufacturing-process sectional drawing of the solid-state image sensor which concerns on the 3rd Embodiment of this invention, Comprising: It is a figure which shows from a transparent resin layer formation process to the photosensitive resin material application process.
  • FIG. 14A is a manufacturing process sectional view of the solid-state imaging device according to the third embodiment of the present invention, showing a process from dry etching a part of the first color filter layer to an etching mask removing process;
  • the solid-state imaging device 1 includes a semiconductor substrate 10 having a plurality of photoelectric conversion elements 11 two-dimensionally arranged, and a plurality of micro-elements disposed above the semiconductor substrate 10.
  • the micro lens group 108 including the lens 18 and the color filter layer 100 and the partition wall 17 provided between the semiconductor substrate 10 and the micro lens 18 are provided.
  • the color filter layer 100 is configured by arranging the color filters 14, 15, 16 of a plurality of colors in a predetermined regular pattern.
  • the partition wall 17 is formed between each of the color filters 14, 15, 16 of a plurality of colors.
  • FIG. 1 shows the solid-state imaging device 1 having a configuration in which the transparent conductive layer 12 is located below the color filter layer 100. Further, the flattening layer 13 is formed between the color filter layer 100 and the microlens group 180 including the plurality of microlenses 18. The planarizing layer 13 may not be the same as the microlens 18 as in an etch back method described later.
  • the color filter with the largest area, which is formed first in the manufacturing process is defined as the color filter 14 of the first color.
  • the color filter formed second in the manufacturing process is defined as the color filter 15 of the second color
  • the color filter formed third in the manufacturing process is defined as the color filter 16 of the third color.
  • the area occupied by the first color filter 14 is the widest.
  • the color filter 14 of the first color contains a thermosetting resin and a photocurable resin.
  • the content of the photocurable resin is less than the content of the thermosetting resin.
  • the color filter 14 of the first color may not be the color filter with the largest area, and may not be the color filter formed first.
  • the color filter layer 100 is composed of three colors of green, blue and red of multiple colors and is arranged in the arrangement pattern of the Bayer array, but the color filter layer consisting of four or more colors is exemplified. It may be In the following description, the first color is assumed to be green, but the first color may be blue or red.
  • each part of the solid-state imaging device will be described in detail.
  • a plurality of photoelectric conversion elements 11 are two-dimensionally arranged corresponding to pixels.
  • the plurality of photoelectric conversion elements 11 have a function of converting light into an electrical signal.
  • a protective film is formed on the outermost surface of the semiconductor substrate 10 on which the photoelectric conversion element 11 is formed, for the purpose of protecting and planarizing the surface (light incident surface).
  • the semiconductor substrate 10 is formed of a material that transmits visible light and can withstand a temperature of at least about 300.degree. Examples of such a material include Si, oxides such as SiO 2 , nitrides such as SiN, and mixtures thereof, materials containing Si, and the like.
  • Each microlens 18 is disposed above the semiconductor substrate 10 in correspondence with the pixel position. That is, the microlenses 18 are provided on each of the plurality of two-dimensionally arranged photoelectric conversion elements 11 on the color filter layer 100 formed on the semiconductor substrate 10. The microlens 18 condenses the incident light incident on the microlens 18 on each of the photoelectric conversion elements 11 to compensate for the decrease in sensitivity of the photoelectric conversion elements 11.
  • the microlens 18 preferably has a height of 300 nm or more and 800 nm or less from the lens top to the lens bottom.
  • the transparent conductive layer 12 is a layer provided for surface protection of the semiconductor substrate 10, planarization, and damage reduction such as charging (charge up) by plasma etching. That is, when the transparent conductive layer 12 reduces unevenness on the upper surface of the semiconductor substrate 10 by the preparation of the photoelectric conversion element 11, improves the adhesion with the color filter material, and patterns the color filter of the first color. It becomes a protective layer of plasma etching.
  • the transparent conductive layer 12 contains, for example, at least one selected from silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine.
  • Compounds or oxides are formed in a single layer or multiple layers.
  • a transparent conductive layer of ITO, ZnO, TiO 2 , HfO 2 or the like can be used as a compound of these materials.
  • the transparent conductive layer 12 is not limited to these oxides and compounds, as long as it is a material that transmits visible light having a wavelength of 400 nm to 700 nm and does not inhibit the pattern formation or adhesion of the color filters 14, 15, 16. Any of these can be used.
  • the transparent conductive layer 12 preferably does not affect the spectral characteristics of the color filters 14, 15, 16.
  • the transparent conductive layer 12 is preferably formed to have a transmittance of 80% or more, more preferably 90% or more, to visible light having a wavelength of 400 nm to 700 nm.
  • the sheet resistivity of the transparent conductive layer 12 is 100,000 ⁇ / sq. It is preferable that the substance be a substance having a lower conductivity. In particular, 5000 ⁇ / sq. Or less, and more preferably 1500 ⁇ / sq. Or less, more preferably 800 ⁇ / sq. It is below.
  • the transparent conductive layer 12 capable of obtaining these sheet resistances is formed of the materials described above. For example, when ITO is used as the transparent conductive layer 12, the sheet resistance is 50 ⁇ / sq. The following can also be formed. The same sheet resistance can be obtained also by using a transparent conductive film in which ZnO is doped with Al or Ga.
  • the transparent conductive layer 12 is preferably made of a compound having a slow etching rate for the purpose of reducing plasma damage in dry etching. Therefore, it is desirable that the material configuration be such that the etching rate of the transparent conductive layer 12 is slower than the etching rate of the color filter 14.
  • the etching rate of transparent conductive layer 12 It is preferable that (G) is 3 times or more slower (3 ⁇ G / T) than the etching rate (T) of the color filter 14, and more preferably 10 times or more slower.
  • the etching of the ITO film hardly progresses.
  • the etching rate is 20 times or more slower than that of the color filter 14, and the setting of the etching rate is satisfied.
  • the transparent conductive layer 12 can satisfy the transmittance, it is preferable to use a transparent resin such as nano ink using Ag, particle aggregate such as nano ITO using inorganic oxide, carbon nanotube ink, conductive polymer, etc. Also good.
  • a transparent resin such as nano ink using Ag, particle aggregate such as nano ITO using inorganic oxide, carbon nanotube ink, conductive polymer, etc. Also good.
  • the film thickness B [nm] of the transparent conductive layer 12 is formed to be more than 0 [nm] and 200 [nm] or less.
  • the film thickness B of the transparent conductive layer 12 is preferably as thin as possible from the viewpoint of transmittance and color mixing prevention, and is more preferably 5 nm or more and 80 nm or less.
  • the flattening layer 13 is used to flatten the top surfaces of the first to third color filters 14, 15, 16 (hereinafter sometimes referred to as "color filters 14, 15, 16") and the partition walls 17. It is a layer provided.
  • the flattening layer 13 is, for example, a resin such as an acrylic resin, an epoxy resin, a polyimide resin, a phenol novolac resin, a polyester resin, a urethane resin, a melamine resin, a urea resin, a urea resin, a styrene resin, and a silicon resin. It is formed of a resin containing one or more. There is no problem even if the flattening layer 13 is integrated with the microlens 18.
  • the film thickness of the planarization layer 13 is, for example, not less than 1 nm and not more than 300 nm. From the viewpoint of preventing color mixing, the thinner the better.
  • the color filters 14, 15, 16 that constitute the color filter layer 100 in a predetermined pattern are filters that correspond to the respective colors that separate incident light.
  • the color filters 14, 15, 16 are provided between the semiconductor substrate 10 and the micro lens 18, and are arranged in a regular pattern set in advance to correspond to each of the plurality of photoelectric conversion elements 11 according to the pixel position. It is done.
  • FIG. 2 is a plan view showing the arrangement of the color filters 14, 15, 16 and the partitions 17 formed between the color filters 14, 15, 16.
  • the arrangement shown in FIG. 2 is a so-called Bayer arrangement, and is an arrangement in which patterns of quadrangular color filters 14, 15 and 16 (first, second and third color filters) are rounded with four corners rounded. It is.
  • Each color filter 14, 15, 16 contains a pigment (colorant) of a predetermined color, and a thermosetting component or a light curing component.
  • the first color filter 14 includes a green pigment as a colorant
  • the second color filter 15 includes a blue pigment
  • the third color filter 16 includes a red pigment.
  • the color filter 14 of the first color contains a thermosetting resin and a photocurable resin, but it is preferable that the blending amount of the thermosetting resin is larger.
  • the curing component in the solid content is 5% by mass to 40% by mass
  • the thermosetting resin is 5% by mass to 20% by mass
  • the photocurable resin is 1% by mass to 20% by mass
  • the thermosetting resin is 5% by mass to 15% by mass
  • the photocurable resin is in the range of 1% by mass to 10% by mass.
  • the curing component in the solid content is in the range of 5% by mass to 40% by mass, more preferably 5% by mass to 15% by mass.
  • the curing component in the solid content is in the range of 10% by mass to 40% by mass, more preferably 10% by mass to 20% by mass.
  • the partition wall 17 is formed between each of the color filters 14, 15, 16 of a plurality of colors.
  • the partition wall 17 provided on the side wall portion of the first color filter 14 separates the first color color filter 14 and the second and third color filters 15 and 16. be able to.
  • the partition wall 17 is a material for the color filter for the first color contained in the color filter 14 for the first color, a material contained in the transparent conductive layer 12, and a dry used for forming the color filter 14 for the first color It contains the reaction product with the etching gas.
  • the material of the partition 17 contains the material contained in the color filter 14 of the first color and the material of the transparent conductive layer 12.
  • the material of the partition 17 includes, for example, a compound containing at least one of zinc, copper, nickel, silicon, carbon, oxygen, hydrogen, nitrogen, bromine and chlorine, and silicon as a material used for the transparent conductive layer 12 It is formed of a compound containing at least one of carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine.
  • a material containing indium, tin, oxygen or the like may be contained in a small amount in the partition wall 17.
  • the amount of etching becomes very small depending on the etching conditions, so the material of the partition wall 17 is mostly occupied by the color filter material of the first color.
  • a solid-state imaging device 1 having the color filters 14, 15, 16 of the Bayer arrangement shown in FIG. 2 will be described.
  • the color filters of the solid-state imaging device 1 are not necessarily limited to the Bayer arrangement, and the colors of the color filters are not limited to three colors of red (R), green (G), and blue (B).
  • a transparent layer whose refractive index is adjusted may be disposed in part of the arrangement of color filters.
  • the film thickness A [nm] of the color filter 14 of the first color is formed to be 200 [nm] or more and 700 [nm] or less.
  • the film thickness A [nm] is 400 [nm] or more and 600 [nm] or less. More preferably, the film thickness A [nm] is 500 [nm] or less.
  • the film thickness B [nm] of the transparent conductive layer 12 is larger than 0 [nm], which is the value described above, and is 200 [nm] or less.
  • the film thickness B [nm] is 5 [nm] or more and 80 [nm] or less. More preferably, the film thickness B [nm] is 50 [nm] or less.
  • the film thickness of the color filters 15 and 16 of colors other than the first color is C [nm]
  • the film thickness is formed to satisfy the following equation.
  • the film thickness of the color filter 15 of the second color may be different from the film thickness of the color filter 16 of the third color.
  • the reason why the film thickness difference between the film thickness of (A + B) and the film thickness of C is 200 nm or less is that there is a portion where the film thickness difference is more than 200 nm. This is because the light receiving sensitivity may be reduced due to the influence of the oblique incident light on the pixel.
  • the formation of the upper microlens 18 may be difficult.
  • the concentration of the pigment (colorant) contained in the first to third color filters 14, 15, 16 is preferably 50% by mass or more.
  • the partition wall 17 is formed between each of the color filters 14, 15, 16 of a plurality of colors.
  • the partition wall is formed to have a width (dimension) of 200 nm or less.
  • the reason why the height of the partition is 200 nm or less is that when the width (dimension) of the partition is larger than 200 nm, the light incident on the photoelectric conversion element 11 is significantly reduced by the partition and the light receiving sensitivity is reduced. It is because there is a fear.
  • the semiconductor substrate 10 which has the several photoelectric conversion element 11 is prepared, and the transparent conductive layer 12 is formed in the color filter layer formation position whole surface of the surface.
  • the transparent conductive layer 12 is made of, for example, one of the aforementioned materials such as silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, fluorine and the like Alternatively, it is formed of a compound containing a plurality of compounds, an oxide compound, a nitride compound, or the like.
  • a film of the above-described compound is formed as the transparent conductive layer 12 by a chemical preparation method such as a spray method, an application method, a CVD method and a physical preparation method such as a vacuum evaporation method, an ion plating method, or a sputtering method.
  • the chemical preparation method is a method of preparing by hydrolysis of chloride or thermal decomposition reaction of an organic compound.
  • the transparent conductive layer 12 may be formed by coating a material containing these materials, heat curing, or the like.
  • the transparent conductive layer 12 is formed on the entire surface of the semiconductor substrate 10, since the electrode portion and the like of the semiconductor substrate 10 are also covered, it is necessary to remove the transparent conductive layer 12 of the electrode portion.
  • a method of partially removing the transparent conductive layer 12 only the removed portion is opened with a mask material and a removal method such as dry etching or wet etching is used, or filling with a material that can be removed beforehand such as liftoff method Known methods such as storage methods can be used.
  • amorphous ITO is formed by non-heating formation, a mask structure is formed using a photoresist, wet etching is performed with oxalic acid, and the electrode portion is opened. Then, the ITO may be crystallized by heating the semiconductor substrate.
  • the manufacturing method of the solid-state imaging device according to the present embodiment is manufactured by directly patterning the color filters 14, 15, 16 constituting the color filter layer 100 by photolithography using a conventional photosensitive color filter material. It is different from the way you do it. That is, in the method of manufacturing the solid-state imaging device 1 according to the present embodiment, the first color filter material is applied to the entire surface and cured to form the first color filter layer 14a (FIG. 3) (See (d)) The portions of the first color filter layer 14a where the other color filters are to be formed are removed by dry etching. Thereby, a pattern of the color filter 14 of the first color (see FIG. 4C) is formed.
  • the reaction product of the first color filter layer 14 a and the transparent conductive layer 12 with the dry etching gas which is generated when the first color filter layer 14 a and the transparent conductive layer 12 are partially dry etched, is used.
  • a partition 17 is formed on the side wall (i.e., the outer periphery) of the color filter 14 of the first color.
  • second and subsequent color filters patterns 15 and 16 of the second and third color filters
  • the second and subsequent color filter materials are cured by high-temperature heat treatment using the pattern of the color filters 14 and partitions 17 of the first color formed previously as a guide pattern. Therefore, the adhesion between the semiconductor substrate 10 and the color filters 15 and 16 can be improved.
  • the formation process will be described.
  • the color filter 14 of the first color is preferably a solid-state imaging device and a color filter with the widest occupied area.
  • the transparent conductive layer 12 is formed on the semiconductor substrate 10 in which the plurality of photoelectric conversion elements 11 are two-dimensionally arranged, and the color filter of the first color is formed on the transparent conductive layer 12
  • the coating solution for 14 is applied and cured to form the transparent conductive layer 12 and the color filter layer 14a of the first color in this order, and then the first color of the first color other than the arrangement position of the color filter 14 A portion of the color filter layer 14a is removed by dry etching to pattern the color filter 14 of the first color.
  • the details of the color filter layer forming step of the first color will be described.
  • a transparent conductive layer 12 is formed on a semiconductor substrate 10 in which a plurality of photoelectric conversion elements 11 are two-dimensionally arranged.
  • a first color color filter material composed of a first resin dispersion liquid in which a first pigment (colorant) is dispersed is applied to form a first color color filter layer 14a.
  • the solid-state imaging device 1 according to the present embodiment is assumed to use a Bayer-arranged color filter as shown in FIG. For this reason, the first color is preferably green (G).
  • the color filter layer 14a of the first color has the same or slightly thicker film thickness as the color filter 14 of the first color to be finally formed, but in FIG. 3 and FIG. The film thickness is shown to be thinner than the color filter 14 of one color (see FIG. 5).
  • thermosetting resin such as an epoxy resin
  • photocurable resin such as an ultraviolet curable resin
  • the compounding amount of the photocurable resin is made smaller than the compounding amount of the thermosetting resin.
  • thermosetting resin By using a large amount of thermosetting resin as the resin material, it is possible to increase the pigment content of the color filter layer 14a of the first color, unlike the case of using a large amount of photocurable resin as the curable resin.
  • a mixed resin containing both a thermosetting resin and a photocurable resin is described, it is not necessarily limited to the mixed resin, and a resin containing only one of the curable resins may be used. .
  • the entire surface of the color filter layer 14a of the first color is irradiated with ultraviolet light to photocure the color filter layer 14a of the first color.
  • the entire surface of the color filter layer 14a of the first color is cured. Therefore, curing is possible even if the content of the photosensitive component is reduced.
  • this exposure step may not be performed. If the solvent resistance described later can be satisfied without containing the photocurable resin, the pigment concentration can be further improved and the film can be thinned by removing the photocurable resin.
  • the color filter layer 14a of the first color is thermally cured at 150 ° C. or more and 300 ° C. or less. More specifically, the heating temperature at the time of curing of the color filter layer 14a of the first color is preferably 170 ° C. or more and 270 ° C. or less.
  • the color filter material of the first color have high temperature resistance because a high temperature heating step of 100 ° C. or more and 300 ° C. or less is often used when forming the microlenses 18 . Therefore, it is more preferable to use a thermosetting resin having high temperature resistance as the resin material.
  • an etching mask pattern having an opening is formed on the first color filter layer 14a formed in the previous step.
  • a photosensitive resin material is applied to the surface of the color filter layer 14a of the first color and dried to form an etching mask 20.
  • the first color corresponding to the position where the color filter 14 of the first color is not formed using a photomask (not shown) for the photosensitive resin layer The area of the color filter layer 14a is exposed to cause a chemical reaction which makes the developer soluble in areas other than the required pattern.
  • the unnecessary portion (exposed portion) of the etching mask 20 is removed by development.
  • the etching mask pattern 20a having the opening 20b is formed.
  • a color filter of the second color or a color filter of the third color is formed in a later step.
  • the photosensitive resin material for example, an acrylic resin, an epoxy resin, a polyimide resin, a phenol novolac resin, and other photosensitive resins may be used alone or in combination or copolymerized.
  • the exposure machine used for the photolithography process which patterns the photosensitive resin layer includes a scanner, a stepper, an aligner, and a mirror projection aligner. Further, exposure may be performed by direct drawing with an electron beam, drawing with a laser, or the like. Above all, a stepper or a scanner is generally used to form the first color color filter 14 of the solid-state imaging device which needs to be miniaturized.
  • a photosensitive resin material As a photosensitive resin material, it is desirable to use a general photoresist in order to produce a pattern with high resolution and high accuracy.
  • a photoresist unlike the case of forming a pattern with a photosensitive color filter material, shape control is easy and a pattern with high dimensional accuracy can be formed.
  • the photoresist used at this time preferably has high dry etching resistance.
  • a thermosetting process called post-baking is often used after development.
  • the heat curing step it may be difficult to remove the remaining resist used as the etching mask in the removal step after dry etching. For this reason, as the photoresist, one which can obtain a selection ratio with the etching member without using the thermosetting process is preferable.
  • the film thickness of the photoresist material needs to be formed thick, but when the film thickness is increased, it becomes difficult to form a fine pattern. Therefore, as the photoresist, a material having high dry etching resistance is preferable.
  • the etching rate ratio (selectivity ratio) of the photosensitive resin material which is an etching mask and the color filter material of the first color which is a target of dry etching is preferably 0.5 or more, and 0.8 or more. Is more preferred. With this selection ratio, it is possible to etch the color filter 14 without eliminating the etching mask pattern 20a altogether.
  • the film thickness of the color filter material of the first color is about 0.2 ⁇ m or more and 0.7 ⁇ m or less
  • the film thickness of the photosensitive resin layer is desirably about 0.5 ⁇ m or more and 2.0 ⁇ m or less.
  • a positive resist or a negative resist may be used without any problem.
  • photoresist removal after etching it is desirable to use a positive resist that tends to undergo a chemical reaction and dissolve in a direction in which the chemical reaction proceeds and dissolves, rather than a negative resist in which the chemical reaction proceeds and hardens due to external factors. .
  • the etching mask pattern is formed.
  • etching method for example, ECR, parallel plate magnetron, DRM, ICP, or dual frequency type RIE (Reactive Ion Etching) may be mentioned.
  • the etching method is not particularly limited, it is a method that can control so that the etching rate and the etching shape do not change even if the line width or area of a large area pattern of several mm or more or a minute pattern of several hundreds of nm is different. Is desirable.
  • the dry etching gas may be a reactive (oxidative / reductive) gas, that is, an etchable gas.
  • the reactive gas include gases containing fluorine, oxygen, bromine, sulfur, chlorine and the like.
  • a rare gas such as argon or helium which is less reactive and contains an element to be etched by physical impact with ions can be used alone or in combination. Therefore, the gas used for dry etching is a gas containing at least one selected from fluorine, oxygen, hydrogen, sulfur, carbon, bromine, chlorine, nitrogen, argon, helium, xenon and krypton.
  • gas containing fluorine for example, CF 4 , C 2 F 6 , C 3 F 8 , C 3 F 6 , C 4 F 8 , C 4 F 10 , CHF 3 , CClF 3 , CCl 3 F, NF 3
  • a dry etching gas in which a plurality of these fluorine-based gases are mixed may be used, such as SF 6 or HF.
  • the total gas flow rate in the initial stage is a gas that performs etching mainly by physical impact of ions such as a rare gas, and uses an etching gas in which a fluorine-based gas or an oxygen-based gas is mixed therein.
  • the chemical reaction is also used to improve the etching rate.
  • the etching is performed under the condition of a large amount of rare gas.
  • the semiconductor substrate 10 of the solid-state imaging device is made of a material mainly made of silicon. Therefore, when dry etching is performed using a highly reactive gas such as a gas containing fluorine, the semiconductor substrate 10 may be etched. Therefore, when dry etching is performed, it is preferable to use a gas that does not etch the semiconductor substrate 10. In addition, in the case of using a gas for etching the semiconductor substrate 10, it is possible to use a gas for etching the semiconductor substrate 10 first and change the semiconductor substrate 10 to a gas that is difficult to etch halfway to perform etching in multiple steps. .
  • the first color filter material can be etched in a shape close to vertical using the etching mask pattern 20a without affecting the semiconductor substrate 10, and residues of the first color color filter may be used. If not formed, the type of etching gas is not limited.
  • the transparent conductive layer 12 is made of a material such as silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, fluorine and the like.
  • a compound containing one or more, an oxide compound, a nitride compound, or the like is used, the color of the desired position is resistant to dry etching with respect to a gas containing fluorine and the etching rate of the transparent conductive layer 12 is slow. It is possible to remove the filter and stop the etching with the transparent conductive layer 12 so that the underlying semiconductor substrate 10 is not etched.
  • the etching may be stopped midway to reduce the ratio of the rare gas to be physically etched.
  • FIG. 5 shows a configuration in which the transparent conductive layer 12 is resistant to the dry etching gas and the etching is hardly advanced.
  • a rare gas may be mixed with the dry etching gas to perform etching with enhanced anisotropy. Under this condition, the physical impact of the rare gas makes it easier for the material of the transparent conductive layer to be contained in the partition wall 17. As described above, as shown in FIG. 5A, the color filter 14 of the first color is formed.
  • Partition forming process (second process)
  • the step of patterning the color filter 14 of the first color As shown in FIG. 5A, it is generated when the color filter layer 14a of the first color and the transparent conductive layer 12 are dry etched.
  • a reaction product (an example of a by-product) is formed on the side wall of the color filter 14 of the first color, with the partition wall 17 finally provided between each of the color filters 14, 15, 16.
  • the partition wall 17 is formed of the color filter material of the first color and the reaction product of the transparent conductive layer material and the dry etching gas.
  • anisotropic etching it is important to control a sidewall protective layer formed by attaching a reaction product by dry etching to the sidewall of the color filter 14 of the first color. Also, depending on the dry etching conditions, the manner and amount of adhesion of the reaction product to the side wall of the color filter 14 of the first color changes.
  • the color filter layer 14a of the first color is etched, and the openings formed by the etching are filled with the color filter material of the second and third colors.
  • Form a multicolor color filter Therefore, in the case of dry etching, it is necessary to vertically etch the color filter layer 14a of the first color and to control the pattern size. Therefore, it is necessary to control the manner and amount of adhesion of the reaction product to the side wall during dry etching.
  • the reaction using physical impact by ions in dry etching makes it possible to increase the deposition amount (adhesion amount) of the reaction product on the side wall.
  • a dry etching gas to be used rare gases such as helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) can be considered, and in particular, Ar and He are preferable.
  • a rare gas containing an element having a low reactivity such as Ar or He is made 90% or more of the total gas flow rate, and one or more types of reactive gas species such as fluorine or oxygen are mixed.
  • a dry etching gas is used.
  • a chemical reaction can be used to improve the etching rate, and the amount of reaction products deposited on the side walls of the first color filter 14 can be controlled.
  • the reaction product deposited on the side wall of the first color filter 14 is formed as the partition wall 17.
  • plasma damage generated during the dry etching step examples include electrical damage due to charge up by plasma, physical damage due to collision of rare gas particles such as Ar ions, and light irradiation damage due to high energy photon irradiation from plasma.
  • the transparent conductive layer 12 having conductivity and a slow etching rate on the surface of the semiconductor substrate 10 has the effect of suppressing the damage of the semiconductor substrate 10 from being damaged.
  • the removal of the etching mask pattern 20a includes, for example, a removal method in which the etching mask pattern 20a is dissolved and peeled without affecting the first color filter 14 by using a chemical solution or a solvent.
  • a solvent for removing the etching mask pattern 20a for example, N-methyl-2-pyrrolidone, cyclohexanone, diethylene glycol monomethyl ether acetate, methyl lactate, butyl lactate, dimethyl sulfoxide, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl
  • a mixed solvent in which an organic solvent such as ether or propylene glycol monomethyl ether acetate is used singly or in combination is used.
  • it is desirable that the solvent used at this time does not affect the color filter material. If it does not affect the color filter material, there is no problem with the peeling method using an acid type chemical.
  • the etching mask pattern 20a can be removed by a method using an ashing technique which is a resist ashing technique using light excitation or oxygen plasma. Also, these methods can be used in combination. For example, first, after removing the deteriorated layer by dry etching of the surface layer of the etching mask pattern 20a using ashing technology which is an ashing technology by light excitation or oxygen plasma, the remaining layers are wet etched using a solvent or the like. The method of removing is mentioned. Further, the etching mask pattern 20a may be removed only by ashing as long as there is no damage to the color filter material of the first color. In addition to the dry process such as ashing, a polishing process by CMP may be used. The above steps complete the patterning of the color filters 14 and the partitions 17 of the first color.
  • color filters 15 and 16 of second and third colors including colors different from the color filter 14 of the first color are formed.
  • the pattern of the first color filter 14 and the partition wall 17 is used as a guide pattern, and a photosensitive color filter material containing a photocurable resin for the second and third color filters 15 and 16 is used. It is a method of forming and exposing selectively by a conventional method to form a pattern.
  • a photosensitive color filter material is formed on the entire surface of the semiconductor substrate 10 on which the color filters 14 and the partitions 17 of the first color are formed as a second color filter material.
  • the photosensitive color filter material used at this time contains a negative photosensitive component that is cured by light irradiation.
  • the film thickness of the color filter 14 of the first color is A [nm]
  • the film thickness of the transparent conductive layer 12 is B [nm]
  • the film thickness of the color filter 15 of the second color is C1 [nm].
  • the film thickness C1 of the color filter 15 of the second color is set so as to satisfy the following equations (1) to (3a). 200 [nm] ⁇ A ⁇ 700 [nm] (1) 0 [nm] ⁇ B ⁇ 200 [nm] (2) A + B-200 [nm] ⁇ C1 ⁇ A + B + 200 (3a)
  • the film thickness C1 may be within the range of (A + B) ⁇ 200 [nm] as in the expression (3a).
  • a portion on which the color filter 15 of the second color is to be formed is exposed using a photomask to form a pattern area of the color filter layer 15a of the second color.
  • FIG. 6C the adhesion between the pattern area of the color filter layer 15a of the second color subjected to exposure and development and the semiconductor substrate 10 is improved, and the heat resistance in actual device utilization is improved.
  • the second color filter layer 15a is cured by performing a curing process at a high temperature. Thereby, the pattern of the color filter 15 of the second color is formed.
  • the temperature used for curing is preferably 200 ° C. or higher.
  • the color filter material of the third color is applied to the entire surface of the semiconductor substrate 10 and dried. That is, the third color filter material is applied to the entire surface outside the pattern area of the second color filter layer 15a to form the third color filter layer 16a.
  • the pattern area forming the color filter 16 of the third color in the color filter layer 16a of the third color is selectively exposed.
  • the color filter layer 16a is photocured to remove the outside of the pattern area of the color filter layer 16a of the third color not exposed by development.
  • FIG. 7C the adhesion between the semiconductor substrate 10 and a part of the third color filter layer 16a subjected to exposure and development is improved, and the heat resistance in actual device utilization is improved.
  • the third color filter layer 16a is cured by performing a curing process at a high temperature. Thereby, the color filter 16 of the third color is formed. In addition, it is possible to form the color filter of a desired number of colors by repeating the pattern formation process after the color filter 15 of this 2nd color.
  • the film thickness of the color filter 16 of 3rd color is set to C2 [nm]
  • the film of the color filter 16 of 3rd color so that the following formula (1)-(3b) may be satisfied.
  • a + B-200 [nm] ⁇ C2 ⁇ A + B + 200 3b
  • the film thickness C2 may be within the range of (A + B) ⁇ 200 [nm] as in the expression (3b).
  • the planarizing layer 13 is formed on the formed color filters 14, 15 and 16 and the partition wall 17.
  • the planarization layer 13 can be formed using, for example, a resin containing one or more resin materials such as an acrylic resin. By applying a resin material on each color filter 14, 15, 16 of a plurality of colors and the partition wall 17 and curing the resin material by heating, the planarization layer 13 can be formed.
  • the planarization layer 13 can be formed using, for example, a compound such as an oxide or a nitride. In this case, the planarization layer 13 can be formed by various film formation methods such as vapor deposition, sputtering, and CVD.
  • the microlenses 18 are formed on the planarization layer 13.
  • the microlenses 18 are formed by known techniques such as a manufacturing method using heat flow, a macro lens manufacturing method using a gray tone mask, and a microlens transfer method to the planarizing layer 13 using dry etching.
  • the film thickness of the planarization layer 13 is, for example, not less than 1 nm and not more than 300 nm. Preferably it is 100 [nm] or less, More preferably, it is 60 [nm] or less.
  • the planarizing layer 13 to be the microlenses finally becomes the microlenses of each color filter 14, 15, 16 of a plurality of colors and Form on the partition wall.
  • a microlens matrix layer 18 a for forming a matrix of microlenses is coated and formed on the planarization layer 13.
  • a resin containing one or more resin materials such as an acrylic resin is used.
  • FIG. 10A exposure is performed using a photomask (not shown), and a lens base 18b of a microlens is formed by a heat flow method.
  • FIG. 10B the shape of the lens base 18b is transferred to the planarizing layer 13 by dry etching using the lens base 18b as a mask.
  • the microlenses 18 having an appropriate lens shape can be transferred to the planarizing layer 13.
  • a plurality of microlenses 18 integrated with the planarization layer 13 are formed.
  • the solid-state imaging device 1 of the present embodiment is completed by the above steps.
  • the color filter 14 of the first color it is preferable to use the color filter 14 of the first color as the color filter with the largest area.
  • the second color filter 15 and the third color filter 16 are formed by photolithography using a photosensitive color resist.
  • the technology using a photosensitive color resist is a conventional color filter pattern manufacturing technology.
  • the color filter material of the first color is coated on the entire surface of the transparent conductive layer 12 and then heated at a high temperature, so that the adhesion with the semiconductor substrate 10 and the transparent conductive layer 12 can be improved. Therefore, the adhesion is good, and the patterns of the color filters 14 and partitions 17 of the first color formed with good rectangularity are used as guide patterns, and the second and third to fill the places where the four sides are surrounded by the partitions 17.
  • Color filters 15, 16 can be formed. Therefore, even when using a color resist having photosensitivity for the second and subsequent color filters, it is not necessary to use a color resist that places emphasis on resolution as in the prior art. For this reason, since the photocurable component in the photocurable resin can be reduced, the proportion of the pigment in the color filter material can be increased, and thin film formation of the color filters 15, 16 can be coped with.
  • both the thermosetting resin and the photocurable resin are used for the color filter 14 of the first color.
  • the color filter 14 of the first color is desirably formed of a color filter material having a low content of resin components and the like involved in photocuring and a high pigment content.
  • the color filter material of the first color is the color of the first color even if it contains a pigment at a concentration that would be insufficiently cured by the conventional photolithography process using a photosensitive color resist
  • the filter 14 can be formed precisely with no residue or peeling.
  • thermosetting resin and a photocurable resin are used in combination.
  • the material is formed of only the thermosetting resin or only the photocurable resin, with emphasis on time-lapse characteristics and the like.
  • thermosetting resin it is possible to increase the pigment concentration, and therefore, it is possible to make the color filter thin.
  • solvent resistance tends to decrease, but there is an advantage that the degree of freedom in material design is improved in terms of temporal characteristics and the like.
  • the partition wall 17 is formed between the color filter 14 of the first color and the color filters 15 and 16 of the second and third colors, and the partition wall 17 is leaked light from other colors and migration. In order to suppress the color mixing, color mixing is suppressed.
  • the transparent conductive layer 12 is provided under the first color filter 14, plasma in the dry etching process for opening the formation locations of the second and third color filters 15 and 16.
  • the damage can be reduced, and the transparent conductive layer having a slow etching rate plays the role of an etching stopper, whereby the possibility of dry etching the semiconductor substrate 10 can be reduced.
  • each color filter is made thin, the total distance from the microlens top to the device is shortened, and color separation is suppressed by having partitions between color filters of a plurality of colors. It is possible to provide a high-definition solid-state imaging device in which all color filters arranged in a pattern are highly sensitive.
  • the solid-state imaging device 2 according to the second embodiment of the present invention has the structure of the first embodiment, and is transparent between the transparent conductive layer 12 and the color filter 14 of the first color. It is a structure with the resin layer 30.
  • the planar arrangement of the color filters 14, 15, 16 of the solid-state imaging device 2 is the Bayer arrangement shown in FIG.
  • the second embodiment is illustrated using figures, as the process up to the first color filter is different.
  • the solid-state imaging device 2 according to the present embodiment is characterized in that the transparent resin layer 30 is formed before the formation of the color filter 14 of the first color.
  • the transparent resin layer 30 is formed before the formation of the color filter 14 of the first color.
  • the solid-state imaging device 2 includes a semiconductor substrate 10 having a plurality of photoelectric conversion elements 11 two-dimensionally arranged, and a plurality of micro-elements disposed above the semiconductor substrate 10.
  • a microlens group 180 consisting of a lens 18 and a transparent conductive layer 12, a color filter layer 100 and a partition 17 provided between the semiconductor substrate 10 and the microlens 18 are provided.
  • the color filter layer 100 is configured by arranging the color filters 14, 15, 16 of a plurality of colors in a predetermined regular pattern.
  • the partition wall 17 is disposed between each of the color filters 14, 15, 16 of a plurality of colors.
  • the flattening layer 13 is formed between the color filter layer 100 and the microlens group 180 including the plurality of microlenses 18.
  • each of the semiconductor substrate 10 having the photoelectric conversion element 11, the transparent conductive layer 12, the color filters 14, 15, 16, the partition wall 17, the planarization layer 13 and the microlens 18 is a solid-state imaging device according to the first embodiment.
  • the configuration is the same as that of each part of 1. Therefore, the detailed description of the parts common to the respective parts of the solid-state imaging device 1 according to the first embodiment will be omitted. The same applies to the other embodiments.
  • Step of forming first color filter layer In the color filter layer forming step of the first color, the transparent conductive layer 12 is formed on the semiconductor substrate 10 on which the plurality of photoelectric conversion elements 11 are two-dimensionally arranged, and the transparent resin layer 30 is formed on the transparent conductive layer 12 The coating liquid for the first color filter 14 is applied and cured to form the transparent conductive layer 12, the transparent resin layer 30, and the first color filter layer 14a in this order, and then the first color is formed. The transparent resin layer 30 located under the first color filter layer 14a portion and the first color color filter layer 14a portion other than the arrangement position of the color filter 14 is removed by dry etching to form a first color Pattern the color filter 14 of FIG.
  • the details of the color filter layer forming step of the first color will be described.
  • the transparent conductive layer 12 is formed on the semiconductor substrate 10 which has the several photoelectric conversion element 11 arrange
  • the transparent conductive layer 12 is a layer provided for surface protection of the semiconductor substrate 10, planarization, and damage reduction such as charging (charge up) by plasma etching. That is, the transparent conductive layer 12 reduces unevenness of the upper surface of the semiconductor substrate 10 by the preparation of the photoelectric conversion element 11, improves the adhesion with the color filter material, and patterns the color filter layer 14a of the first color. It becomes a protective layer of plasma etching at the time of etching.
  • the material and formation method of the transparent conductive layer 12 use what was demonstrated in 1st Embodiment. Thereafter, the transparent conductive layer 12 on the electrode portion or the like of the semiconductor substrate 10 is removed by the same method as in the first embodiment described above.
  • the transparent resin layer 30 is, for example, a resin such as an acrylic resin, an epoxy resin, a polyimide resin, a phenol novolac resin, a polyester resin, a urethane resin, a melamine resin, a urea resin, a urea resin, a styrene resin, and a silicon resin. It is formed of a resin containing one or more.
  • the film thickness of the transparent resin layer 30 is, for example, 1 nm or more and 300 nm or less. From the viewpoint of preventing color mixing, the thinner, the better, and the thickness is preferably 5 nm to 60 nm.
  • the color filter layer 14a of the first color is formed on the transparent resin layer 30, and as shown in FIG. 12 (d), the first color formed.
  • the color filter layer 14a is heated and cured, and as shown in FIG. 12 (e), a photosensitive resin material is applied on the color filter layer 14a of the first color that has been effected and dried.
  • a resin material layer is formed, and an etching mask 20 is formed.
  • the color filter layer 14a of the first color has the same or slightly thicker film thickness as the color filter 14 of the first color to be finally formed, but in FIG. 12 and FIG. The film thickness is shown to be thinner than the color filter 14 of one color (see FIG. 14).
  • a photomask (not shown) is used to expose and develop so that the formation locations of the color filters 15 and 16 of the second and third colors are opened.
  • the etching mask pattern 20a having the opening 20b is formed.
  • the etching mask pattern 20a As shown in FIG. 14A, the first color of the first color exposed from the opening 20b by dry etching using the dry etching gas described in the first embodiment. A portion of the color filter layer 14a is removed.
  • the transparent resin layer 30 is located under the first color filter 14, it is desirable to perform the etching with a dry etching gas that can etch the transparent resin layer 30. Further, it is desirable to etch the color filter layer 14a of the first color with good rectangularity by using the etching mask pattern 20a.
  • 90% or more of the total gas flow rate in the initial stage is a gas that performs etching mainly by physical impact of ions such as a rare gas, and uses an etching gas in which a fluorine-based gas or an oxygen-based gas is mixed therein. Thus, the chemical reaction is also used to improve the etching rate.
  • the etching is performed under the condition of a large amount of rare gas. Specifically, 90% or more of the total gas flow rate of the single gas of the rare gas or the mixed gas of the reactive gas and the rare gas etches part or all of the color filter layer 14a of the first color with the rare gas.
  • the remaining first color filter layer 14 a and the transparent resin layer 30 are etched to stop at the underlying transparent conductive layer 12.
  • the first color color filter layer 14 a and the transparent resin layer 30 remaining are etched using oxygen and a fluorine-based gas as a gas for which the transparent conductive layer 12 is etched slowly.
  • the conditions used here are that the etching rate of the transparent conductive layer 12 is low and the transparent resin layer 30 is easily removed by a chemical etching reaction, so the color filter 14 of the first color is etched without residue and the transparent conductive layer 12 Do it in time that will not disappear.
  • FIG. 14 shows a configuration in which the transparent conductive layer 12 is resistant to the dry etching gas and the etching is hardly advanced except for a part.
  • the color filter layer 14a of the first color and the first color filter layer 14a are adjusted by adjusting the time for etching the film thickness twice to three times the remaining film thickness of the first color filter layer 14a. It is desirable that the transparent resin layer 30 be etched without residue.
  • the transparent resin layer 30 is removed by etching at the color filter formation locations other than the color filter 14 of the first color. Therefore, as shown in FIG. 11, when the heights of the tops of the color filters of a plurality of colors are equalized, the film thickness of the color filters of the second and subsequent colors is It is possible to adjust the thickness of the transparent resin layer 30 as thick as possible. Therefore, even if a photocurable resin is used for the color filters of the second and subsequent colors, there is an advantage that the adjustment range of the pigment concentration can be expanded by the film thickness.
  • the steps after the above steps that is, the partition forming step (second step), the etching mask pattern removing step and the second and subsequent color filter pattern forming steps (third step) are the same as in the first embodiment described above. Are the same as those described in the above.
  • the solid-state imaging device 2 of the present embodiment is completed by the above steps.
  • the invention according to the second embodiment has the following effects in addition to the effects described in the first embodiment. Since the transparent resin layer 30 is present between the transparent conductive layer 12 and the color filter 14 of the first color, the transparent resin layer 30 which is easily etched by a chemical reaction of dry etching is under the color filter which easily remains as a residue. Because of the presence, dry etching residue of the color filter 14 of the first color does not easily occur, and etching becomes possible.
  • the solid-state imaging device 3 is characterized in that a transparent resin layer 30 is formed between the semiconductor substrate 10 and the transparent conductive layer 12 shown in FIG. For this reason, after the semiconductor substrate 10 is planarized, the transparent conductive layer 12 can be formed, and since the semiconductor substrate 10 and the transparent conductive layer 12 are not directly connected, plasma damage due to dry etching occurs from the transparent conductive layer 12 to the semiconductor It is hard to be transmitted to the substrate 10, and there is an advantage that the reduction of plasma damage is effective.
  • the structure of the solid-state imaging device according to the present embodiment is the same as the first embodiment in the process of forming the color filter 14 of the first color, and the transparent resin layer 30 is the same as that of the second embodiment. However, the difference is that the step of forming the transparent resin layer 30 is between the semiconductor substrate 10 and the transparent conductive layer 12. For this reason, the process of forming the transparent resin layer is described.
  • a transparent resin material is applied on the semiconductor substrate 10 and heated to form a transparent resin layer 30.
  • the material of the transparent resin layer 30 is the material described in the second embodiment.
  • the transparent conductive layer 12 is formed on the transparent resin layer 30.
  • the color filter layer 14a of the first color is formed on the transparent conductive layer 12 by coating.
  • the color filter layer 14a of the first color has the same or slightly thicker film thickness as the color filter 14 of the first color to be finally formed, but in FIG. 16 and FIG.
  • the film thickness is shown to be thinner than the color filter 14 of one color (see FIG. 18).
  • FIG. 16D the entire surface of the first color filter layer 14a is thermally cured by heating.
  • a photosensitive resin material is applied on the color filter layer 14a of the first color and dried to form a photosensitive resin material layer, and an etching mask 20 is formed. .
  • the etching mask 20 is exposed so as to open the portions where the color filters of the second and third colors are formed, and then developed.
  • an etching mask pattern 20a having an opening 20b is formed.
  • the first color filter layer 14a exposed in the opening 20b is etched by dry etching, and then, as shown in FIG. 18B, the etching mask pattern 20a is formed. Remove.
  • the steps shown in FIG. 18 and the steps thereafter are the same as the steps described in the first embodiment described above.
  • the solid-state imaging device 3 of the present embodiment is completed by the above steps.
  • the invention according to the third embodiment has the following effects in addition to the effects described in the first embodiment. Since the transparent resin layer 30 is present between the transparent conductive layer 12 and the color filter 14 of the first color, the transparent resin layer 30 which is easily etched by a chemical reaction of dry etching is under the color filter which easily remains as a residue. Since it is present, dry etching residue of the color filter is unlikely to occur and etching becomes possible.
  • solid-state imaging device of the present invention and the solid-state imaging device according to the conventional method will be specifically described by way of examples.
  • Example 1 An ITO film was formed as a transparent conductive layer to a film thickness of 50 nm on the semiconductor substrate provided with the two-dimensionally arranged photoelectric conversion element using a magnetron sputtering method.
  • the film formation temperature was formed near normal temperature so as to be an amorphous film in order to facilitate processing.
  • wet etching was performed using an etching solution containing about 5% of oxalic acid.
  • a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation number of 750 rpm and then prebaked at 90 ° C. for 1 minute.
  • a sample in which a positive resist serving as an etching mask was applied with a film thickness of 2.0 ⁇ m was produced.
  • the sample was subjected to photolithography which was exposed through a photomask.
  • the exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source.
  • the positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
  • a development step was performed using 2.38% by mass of TMAH (tetramethylammonium hydride) as a developing solution to form an etching mask having an opening in the electrode portion of the semiconductor substrate.
  • TMAH tetramethylammonium hydride
  • the method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus. Next, heat treatment was performed on a hot plate at 250 ° C. for 30 minutes to crystallize the ITO film. At this time, the sheet resistance is 50 ⁇ / sq. It is below and the transmittance
  • a green pigment dispersion containing a photosensitive curable resin and a thermosetting resin was spin-coated at a rotational speed of 1000 rpm as a first color filter material containing a green pigment, which is the first color.
  • the green pigment of the first color material for the color filter has C.I. I. PG 58 was used, the pigment concentration was 70% by mass, and the film thickness was 500 nm.
  • the entire surface was exposed using a stepper which is an i-line exposure device to cure the photosensitive component.
  • the surface of the green filter was cured by curing the photosensitive component.
  • baking was performed at 230 ° C. for 6 minutes on a hot plate to thermally cure the green filter.
  • a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin coated using a spin coater at a rotation number of 1000 rpm, and then prebaked at 90 ° C. for 1 minute.
  • the sample was subjected to photolithography which was exposed through a photomask.
  • the exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source.
  • the positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
  • a development step is performed using 2.38% by mass of TMAH (tetramethyl ammonium hydride) as a developer to form an etching mask having an opening at a position where a color filter of the second and third colors is formed.
  • TMAH tetramethyl ammonium hydride
  • dehydration baking is often performed after development to cure the positive resist.
  • the bake step was not performed. Therefore, since the resist is not cured and improvement in selectivity can not be expected, the film thickness of the resist is formed to a film thickness of 1.5 ⁇ m which is twice or more of the film thickness of the first color filter which is a green filter. did.
  • the opening pattern at this time was formed to be 1.1 ⁇ m ⁇ 1.1 ⁇ m. Thus, an etching mask pattern using a positive resist was formed.
  • dry etching of the green filter layer was performed using the formed etching mask pattern.
  • the dry etching apparatus used was an ICP dry etching apparatus.
  • dry etching conditions were changed on the way so as not to affect the underlying semiconductor substrate, and dry etching was performed in multiple steps.
  • the first gas species were etched by mixing three kinds of CF 4 , O 2 and Ar gas.
  • the gas flow rates of CF 4 and O 2 were 5 ml / min, and the gas flow rate of Ar was 200 ml / min. That is, the gas flow rate of Ar was 95.2% in the total gas flow rate.
  • the dry etching conditions in this case set the pressure in a chamber to a pressure of 1 Pa, RF power was set to 500 W, and coil power was set to 1000 W.
  • the dry etching conditions were changed to the following dry etching conditions when dry etching was performed on 350 nm of the film thickness of 500 nm of the green filter layer using this condition.
  • the next gas species is a mixed gas of CF 4 gas and O 2 gas, and the etching conditions are 50 ml / min at a gas flow rate of 150 ml / min for CF 4 and 150 ml / min for an O 2 gas flow rate.
  • the mixture was mixed, the pressure in the chamber was 2 Pa, the RF power was 500 W, and the coil power was 1000 W. Dry etching of the remaining portion of the green filter layer was performed using this condition.
  • the ITO film formed as a transparent conductive layer has a configuration in which the etching rate of CF 4 gas and O 2 gas is 20 times or more slower than the etching rate of green and almost no etching occurs, so no green residue is left at this time.
  • the over-etching was performed with a time setting in which three times 450 nm of the remaining green filter film thickness of 150 nm was etched. According to this process, the green filter did not leave any residue, and the ITO film was etched 5 nm out of the film thickness of 50 nm.
  • partition walls were formed on the side walls of the green filter pattern, which contained a reaction product of a green filter material and an ITO material which is a transparent conductive layer, and a dry etching gas.
  • This partition can control the dimension (width) of the partition by adjusting the time of dry etching conditions.
  • the green filter was dry etched to 500 nm and the transparent conductive layer to 5 nm, but the dimensions of the partition walls due to their reaction products were 25 nm.
  • the positive resist used as the etching mask was removed.
  • the method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus.
  • a color filter formation step of the second color was performed.
  • a photosensitive blue resist containing pigment dispersion blue was applied over the entire surface of the semiconductor substrate to provide a second color filter.
  • HMDS treatment may be performed to improve the adhesion before applying the blue resist.
  • the blue resist was selectively exposed by photolithography and development was performed to form a blue filter pattern.
  • the pigment used for the blue resist has C.I. I. PB 156, C.I. I. It was PV23, and the pigment concentration was 50% by mass.
  • the film thickness of the blue filter was 550 nm.
  • an acrylic resin having photosensitivity was used as a resin which is a main component of the blue resist.
  • a color filter formation step of the third color was performed.
  • a photosensitive red resist containing pigment dispersed red was applied over the entire surface of the semiconductor substrate to provide a third color filter.
  • the red resist was selectively exposed by photolithography and developed to form a red filter pattern.
  • the pigment used for the red resist has C.I. I. PR 254, C.I. I. PY 139, and the pigment concentration was 60% by mass.
  • the film thickness of the red filter was 550 nm.
  • the color filter of the third color is covered with a green filter and a partition having good rectangularity, and is formed with good rectangularity, so that it can be cured with good adhesion between the bottom and the periphery. confirmed.
  • the film thickness C (550 nm) is the film thickness based on the present invention.
  • a transparent conductive layer is formed to a film thickness of 45 nm below the color filter layers of the second and third colors.
  • a coating solution containing an acrylic resin is spin-coated at a rotational speed of 1000 rpm on the color filter formed in the above process, and heat treated at 200 ° C. for 30 minutes on a hot plate to cure the resin and flat. Layer was formed.
  • a microlens having a height from the lens top to the lens bottom of 500 nm is formed using the transfer method by etch back which is the above-mentioned known technique, and the solid-state imaging device of Example 1 Completed.
  • the green filter which is the first color
  • the concentration of the pigment in the solid content can be increased, and the film thickness at which desired spectral characteristics can be obtained
  • the color filter can be made thinner than when patterning using a photosensitive resist of
  • blue and red which are color filters for the second and third colors, use photosensitive resins, but unlike the conventional process, the color filter for the first color has a rectangular pattern with good rectangularity and is a guide pattern Only fill in the part where Therefore, since blue and red can reduce the proportion of the photosensitive resin as compared with the prior art, there is an advantage that it is easy to form the spectral characteristics to be obtained even if the film thickness is thin by increasing the pigment concentration.
  • the respective colors of green, blue and red can be made thinner than in the conventional process, the distance from the microlens to the semiconductor substrate becomes smaller, and the film has excellent sensitivity. Further, the visible light transmittance of the transparent conductive layer is 89%, and the dimension of the formed partition is 25 nm, which satisfies the definition of the present invention.
  • a transparent conductive layer on the semiconductor substrate at the time of etching plays a role of an etching stopper at the time of etching, and has conductivity, so it has an effect of escaping plasma damage at the time of dry etching of green. No influence of dry etching was observed on the photoelectric conversion element.
  • the material for the color filter of the first color filter comprising green filters hardens the inside by heat curing, and hardens the surface by exposure using a small amount of photosensitive resin, thus improving the solvent resistance.
  • a green filter material having a high pigment content it may react with a solvent or another color filter material to change its spectral characteristics. Therefore, it becomes possible to improve solvent tolerance by using the above-mentioned thermosetting and photocuring together, and there is an effect which controls change of spectral characteristics.
  • the green filter which is the color filter of the first color
  • a material in which the thermosetting resin and the photocurable resin are used in combination is used.
  • the material is formed of only the thermosetting resin or only the photocurable resin, with emphasis on pigment concentration, time-dependent characteristics and the like.
  • the film thickness is thicker than that of green in order to obtain the spectral characteristics required for blue and red. Therefore, it does not have a structure in which the heights of green, blue and red are aligned as shown in FIG. 1 (a), but the structure in which blue and red project about 50 nm.
  • Example 2 is an example corresponding to the solid-state imaging device having the configuration described in the second embodiment.
  • the solid-state imaging device of Example 2 has a configuration in which a transparent resin layer is formed on a transparent conductive layer. By the presence of the transparent resin layer, the adhesion of the color filter is improved, and when etching the color filter of the first color, there is an effect that it is difficult to generate a residue.
  • An ITO film was formed as a transparent conductive layer to a film thickness of 30 nm using magnetron sputtering on a semiconductor substrate provided with photoelectric conversion elements arranged two-dimensionally.
  • the film formation temperature was formed near normal temperature so as to be an amorphous film in order to facilitate processing.
  • wet etching was performed using an etching solution containing about 5% of oxalic acid.
  • a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation number of 750 rpm and then prebaked at 90 ° C. for 1 minute.
  • a sample in which a positive resist serving as an etching mask was applied with a film thickness of 2.0 ⁇ m was produced.
  • the sample was subjected to photolithography which was exposed through a photomask.
  • the exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source.
  • the positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
  • a development step was performed using 2.38% by mass of TMAH (tetramethylammonium hydride) as a developing solution to form an etching mask having an opening in the electrode portion of the semiconductor substrate.
  • TMAH tetramethylammonium hydride
  • the method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus. Next, heat treatment was performed on a hot plate at 250 ° C. for 30 minutes to crystallize the ITO film. At this time, the sheet resistance is 50 ⁇ / sq. It is below and the transmittance
  • a coating solution containing an acrylic resin is spin coated at 3000 rpm on ITO, which is a transparent conductive layer formed on a semiconductor substrate, and heat treated at 230 ° C. for 6 minutes on a hot plate to cure the resin. And a transparent resin layer was formed. The thickness of the transparent resin layer at this time was 30 nm, and the visible light transmittance was 95%.
  • a green pigment dispersion liquid containing a photosensitive curable resin and a thermosetting resin was spin-coated at a rotational speed of 1000 rpm as a color filter material of a first color filter (green filter).
  • the green pigment of the first color material for the color filter has C.I. I. PG 58 was used, the pigment concentration was 70% by mass, and the film thickness was 500 nm.
  • the entire surface was exposed using a stepper which is an i-line exposure device to cure the photosensitive component.
  • the surface of the green filter was cured by curing the photosensitive component.
  • baking was performed at 230 ° C. for 6 minutes on a hot plate to thermally cure the green filter.
  • Example 1 Formation of the color filter of the first color
  • the green filter layer and the transparent resin layer were etched.
  • the etching conditions are the same as in Example 1.
  • the over-etching was performed to adjust the time to etch 450 nm, which is three times 150 nm of the remaining portion of the green filter, but this time the over-etching is performed in the time to etch 300 nm of the green filter. did.
  • the green filter and the transparent resin layer were all etched where the color filters of the second and third colors were formed, and the thickness of the transparent conductive layer was almost unchanged from 30 nm. Thereafter, the positive resist used as the etching mask was removed by the method described in Example 1.
  • This partition can control the dimension (width) of the partition by adjusting the time of dry etching conditions.
  • the green filter was dry etched to 500 nm and the transparent resin layer to 30 nm, but the dimensions of the partition walls due to their reaction products were 30 nm.
  • Example 2 (Preparation of second and third color filters etc.)
  • the color filters for the second and third colors, the flattening layer on the upper layer, and the microlenses were formed by the same method as in Example 1, and the solid-state imaging device of Example 2 was formed.
  • Example 2 also has the film thickness of 500 nm of the green color filter of the first color and the film thickness of the transparent resin layer below it of 30 nm, and the film thickness of the transparent conductive layer below it. 30 nm, 550 nm film thickness of blue and red which are color filters of second and third colors, visible light transmittance (95%) of transparent resin layer and transparent conductive layer, dimension E (30 nm) of partition wall The requirements of the invention are satisfied. Further, in the present embodiment, only the lower layer of the second and third color filter layers has no transparent resin layer, and only the transparent conductive layer is formed. In this embodiment, the film thickness is thicker than that of green in order to obtain the spectral characteristics required for blue and red. Therefore, as shown in FIG. 1 (b), the structure is not a structure in which the heights of green, blue and red are aligned, but a structure in which blue and red protrude by about 20 nm.
  • the thickness of the transparent conductive layer is reduced to 50 nm to 30 nm as compared with the first embodiment. This is because as the film thickness of the transparent resin layer and the transparent conductive layer becomes thicker, the distance from the color filter to the photoelectric conversion element becomes longer, and the light receiving sensitivity is easily lowered due to color mixing or the like. Moreover, since the light transmittance of the visible light of the transparent resin layer and the transparent conductive layer is not 100%, the transmittance tends to decrease when the thickness is increased.
  • the thicker the film thickness of the transparent resin layer and the transparent conductive layer the wider the range of conditions in the manufacturing process, so color mixing occurs and the transmittance decreases.
  • the film thickness can be formed within the range in which the light receiving sensitivity does not deteriorate.
  • Example 3 is an example corresponding to the solid-state imaging device having the configuration described in the third embodiment.
  • the solid-state imaging device shown in Example 3 has a configuration in which a transparent resin layer is present between the semiconductor substrate of Example 1 and the transparent conductive layer.
  • the presence of the transparent resin layer makes it possible to further planarize the semiconductor substrate, so that a transparent conductive layer such as ITO can be easily formed with good performance.
  • a transparent conductive layer such as ITO can be easily formed with good performance.
  • the semiconductor substrate and the transparent conductive layer are not in direct contact with each other, plasma damage during dry etching of the color filter is unlikely to affect the semiconductor substrate.
  • a coating solution containing an acrylic resin is spin-coated on a semiconductor substrate at a rotational speed of 2000 rpm, and heat treatment is performed on a hot plate at 200 ° C. for 20 minutes to cure the resin to form a transparent resin layer.
  • the transparent resin layer had a thickness of 60 nm and a visible light transmittance of 91%.
  • an ITO film was formed as a transparent conductive layer on the transparent resin layer to a film thickness of 30 nm using magnetron sputtering.
  • the film formation temperature was formed near normal temperature so as to be an amorphous film in order to facilitate processing.
  • wet etching was performed using an etching solution containing about 5% of oxalic acid.
  • a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation number of 750 rpm and then prebaked at 90 ° C. for 1 minute.
  • a sample in which a positive resist serving as an etching mask was applied with a film thickness of 2.0 ⁇ m was produced.
  • the sample was subjected to photolithography which was exposed through a photomask.
  • the exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source.
  • the positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
  • a development step was performed using 2.38% by mass of TMAH (tetramethylammonium hydride) as a developing solution to form an etching mask having an opening in the electrode portion of the semiconductor substrate.
  • TMAH tetramethylammonium hydride
  • the method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus. Next, heat treatment was performed on a hot plate at 250 ° C. for 30 minutes to crystallize the ITO film. At this time, the sheet resistance is 50 ⁇ / sq. It is below and the transmittance
  • a green pigment dispersion liquid containing a photosensitive curable resin and a thermosetting resin was spin-coated at a rotational speed of 1000 rpm as a color filter material of a first color filter (green filter).
  • the green pigment of the first color material for the color filter has C.I. I. PG 58 was used, the pigment concentration was 70% by mass, and the film thickness was 500 nm.
  • the entire surface was exposed using a stepper which is an i-line exposure device to cure the photosensitive component.
  • the surface of the green filter was cured by curing the photosensitive component.
  • baking was performed at 230 ° C. for 6 minutes on a hot plate to thermally cure the green filter.
  • Example 3 after patterning the color filter of the first color by dry etching in the same manner as in Example 1, the color filter for the second and third colors, the flattening layer on the upper layer, and the microlens The solid-state imaging device of Example 3 was formed.
  • the film thickness A (500 nm) of the green color filter of the first color and the film thickness B (30 nm) B of the transparent conductive layer therebelow of the third embodiment are the same as the first embodiment.
  • the transparent conductive layer can be formed with a thin film with good quality, and there is an effect that plasma damage by dry etching does not affect the semiconductor substrate.
  • the transparent resin layer is removed by a known method such as wet etching to make hard transparent conductive such as crystallized ITO etc.
  • the layer can be easily removed. Therefore, there is an advantage that the process margin can be expanded, such as reworking of the process.
  • the film thickness is thicker than that of green in order to obtain the spectral characteristics required for blue and red. Therefore, as shown in FIG. 15, the structure is not a structure in which the heights of green, blue and red are aligned, but a structure in which blue and red protrude by about 50 nm.
  • ⁇ Conventional method> Based on the conventional method described in Patent Document 1, a color filter pattern of each color was formed by a photolithography process. However, the film thickness of three colors of green, blue and red was set to a thin film of 700 nm, and a transparent resin layer (100 nm) was provided in the lower layer of all color filters of each color. A solid-state imaging device was manufactured by the conventional method in the same manner as in the first embodiment except for the above.
  • the presence or absence of the transparent resin layer, the difference in the formation position of the transparent resin layer, and the difference in the height (thickness) of the transparent resin layer and the transparent conductive layer The film thickness (30 nm to 50 nm) of the lower transparent conductive layer, the film thickness (30 nm) of the transparent resin layer, and the film thicknesses of blue and red (550 nm) which are color filters of the second and third colors are the present invention.
  • the film thickness specified in is satisfied.
  • the film characteristics of the three colors of green, blue and red are combined at 700 nm by the conventional photolithography.
  • the intensities of the red, green and blue signals of the manufactured solid-state imaging device were compared and evaluated.
  • the signal intensity of each color is increased as compared with the case of forming by the conventional photolithography. This is because, when the oblique light from the diagonal direction of the pixel passes through the color filter and travels to another color filter pattern by the partition, the incidence is blocked by the partition or the light path is changed. For this reason, it is suppressed that the light which goes to another color filter pattern injects into another photoelectric conversion element, and color mixing is suppressed. In addition, since color separation from other colors is also blocked by the partition wall, color mixing is suppressed.
  • the probability that incident light from an oblique direction passes through a color filter and travels to another color filter pattern is reduced by thinning as well, and light traveling to another color filter pattern may be incident on another photoelectric conversion element. Since the suppression was performed and the color mixing was suppressed, the signal intensity increased.
  • the change of the light reception sensitivity was confirmed slightly by the change of the formation position of a transparent conductive layer and a transparent resin layer using the method of Example 1 to Example 3.
  • FIG. the influence of plasma damage due to dry etching on the photosensitivity was not confirmed.
  • the height of the color filter 15 of the second color and the color filter 16 of the third color is lower than the sum of the film thickness of the color filter 14 of the first color and the transparent resin layer 30 and the transparent conductive layer 12
  • the signal content was increased by increasing the pigment content as much as the film thickness was reduced, as compared with the case of forming by photolithography in the conventional method.

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Abstract

Provided is a solid-state image capture element in which color mixing is suppressed and which has high resolution and sensitivity. The solid-state image capture element is characterized by being provided with: a semiconductor substrate having a plurality of photoelectric conversion elements two-dimensionally arranged thereon; a color filter layer which is formed on the semiconductor substrate, and in which a plurality of colors of color filters are two-dimensionally arranged in a preset regular pattern in correspondence to the plurality of photoelectric conversion elements; a separating wall disposed between the plurality of colors of color filters; and a transparent conductive layer disposed between a color filter of a first color selected from the plurality of colors and the semiconductor substrate.

Description

固体撮像素子およびその製造方法Solid-state imaging device and method of manufacturing the same
　本発明は、ＣＣＤ、ＣＭＯＳ等の光電変換素子を使用した固体撮像素子に関する技術である。 The present invention relates to a technology relating to a solid-state imaging device using photoelectric conversion devices such as CCDs and CMOS.
　デジタルカメラ等に搭載されるＣＣＤ（電荷結合素子）やＣＭＯＳ（相補型金属酸化膜半導体）等の固体撮像素子は、近年、高画素化、微細化が進んでおり、その画素は、特に微細なものでは１．４μｍ×１．４μｍを下回るレベルの画素サイズとなっている。 Solid-state imaging devices such as CCDs (charge-coupled devices) and CMOS (complementary metal oxide semiconductors) mounted on digital cameras etc. have recently been increased in the number of pixels and miniaturized, and the pixels are particularly fine. In the pixel size, the pixel size is below 1.4 μm × 1.4 μm.
　固体撮像素子は、光電変換素子と一対の色フィルターパターンを有し、カラー化を図っている。また、固体撮像素子の光電変換素子が光電変換に寄与する領域（開口部）は、固体撮像素子のサイズや画素数に依存する。その開口部は、固体撮像素子の全面積に対し、２０～５０％程度に限られている。開口部が小さいことはそのまま光電変換素子の感度低下につながることから、固体撮像素子では感度低下を補うために光電変換素子上に集光用のマイクロレンズを形成することが一般的である。 The solid-state imaging device has a photoelectric conversion device and a pair of color filter patterns to achieve colorization. Moreover, the area | region (opening part) which the photoelectric conversion element of a solid-state image sensor contributes to photoelectric conversion depends on the size and the number of pixels of a solid-state image sensor. The opening is limited to about 20 to 50% of the total area of the solid-state imaging device. Since a small opening directly leads to a decrease in the sensitivity of the photoelectric conversion element, it is general in a solid-state imaging element to form a microlens for collecting light on the photoelectric conversion element in order to compensate for the reduction in sensitivity.
　また、近年裏面照射の技術を用いたイメージセンサが開発されており、光電変換素子の開口部を固体撮像素子の全面積の５０％以上にすることができるようになっている。しかしながら、この場合、色フィルターに隣接する色フィルターの漏れ光が入る可能性があるため、適切なサイズ、形状のマイクロレンズを形成することが必要となっている。 Further, in recent years, an image sensor using a backside illumination technology has been developed, and the opening of the photoelectric conversion element can be 50% or more of the entire area of the solid-state imaging element. However, in this case, it is necessary to form a micro lens of an appropriate size and shape because leaked light from the color filter adjacent to the color filter may enter.
　このような色フィルターパターンを固体撮像素子上に形成する方法としては、通常は特許文献１のようにフォトリソグラフィプロセスによりパターンを形成する手法が用いられる。 As a method of forming such a color filter pattern on a solid-state imaging device, a method of forming a pattern by a photolithography process as in Patent Document 1 is generally used.
　また、色フィルターパターンを固体撮像素子上に形成する他の方法としては、特許文献２には、全ての色フィルターパターンをドライエッチングによって形成する方法が記載されている。 Further, as another method of forming a color filter pattern on a solid-state imaging device, Patent Document 2 describes a method of forming all the color filter patterns by dry etching.
　近年、８００万画素を超える高精細ＣＣＤ撮像素子への要求が大きくなり、これら高精細ＣＣＤにおいて付随する色フィルターパターンの画素サイズとして１．４μｍ×１．４μｍを下回るレベルの撮像素子への要求が大きくなっている。しかしながら、画素サイズを小さくすることにより、フォトリソグラフィプロセスにより形成された色フィルターパターンの解像性が不足し、固体撮像素子の特性に悪影響を及ぼすという問題が生じている。一辺が１．４μｍ以下、あるいは１．１μｍや０．９μｍ近傍の固体撮像素子では、解像性の不足がパターンの形状不良に起因する色むらとなって現れる。 In recent years, the demand for high-definition CCD imaging devices exceeding 8 million pixels has increased, and the demand for imaging devices having levels below 1.4 μm × 1.4 μm as pixel sizes of color filter patterns attached to these high-definition CCDs It is getting bigger. However, reducing the pixel size causes a problem that the resolution of the color filter pattern formed by the photolithography process is insufficient, which adversely affects the characteristics of the solid-state imaging device. In a solid-state imaging device having one side of 1.4 μm or less, or 1.1 μm or near 0.9 μm, lack of resolution appears as color unevenness due to pattern defect.
　色フィルターパターンの画素サイズが小さくなると、色フィルターパターンのアスペクト比（色フィルターパターンの幅に対して高さ（厚み））が大きくなる。このような色フィルターパターンをフォトリソグラフィプロセスで形成する場合、本来除去されるべき部分（画素の有効外部分）の色フィルターが完全に除去されず、残渣となって他の色の画素に悪影響を及ぼしてしまう。残渣を除去するために現像時間を延長する等の方法を行った場合、硬化させた必要な画素まで剥がれてしまうという問題も発生している。 As the pixel size of the color filter pattern decreases, the aspect ratio of the color filter pattern (height (thickness) with respect to the width of the color filter pattern) increases. When such a color filter pattern is formed by a photolithography process, the color filter of the portion to be originally removed (the non effective portion of the pixel) is not completely removed and becomes a residue and adversely affects the pixels of other colors. It will exert. When a method such as extending the development time is performed to remove the residue, there is also a problem that the hardened necessary pixels are peeled off.
　また、満足する分光特性を得ようとすると、色フィルターの膜厚を厚くせざるを得ない。しかしながら、色フィルターの膜厚が厚くなると、画素の微細化が進むに従って、色フィルターパターンの角が丸まる等、解像度が低下する傾向となる。色フィルターパターンの膜厚を厚くし且つ分光特性を得ようとすると、色フィルターパターン材料に含まれる顔料濃度を上げる必要がある。しかしながら、色フィルターパターン材料に含まれる顔料濃度を上げると光硬化反応に必要な光が色フィルターパターン層の底部まで届かず、色フィルター層の硬化が不充分となる。このため、フォトリソグラフィにおける現像工程で色フィルターの層が剥離し、画素欠陥が発生するという問題がある。 In addition, in order to obtain satisfactory spectral characteristics, the thickness of the color filter must be increased. However, when the film thickness of the color filter is increased, the resolution tends to be reduced, for example, the corners of the color filter pattern are rounded as the miniaturization of the pixels progresses. In order to increase the film thickness of the color filter pattern and to obtain spectral characteristics, it is necessary to increase the pigment concentration contained in the color filter pattern material. However, when the pigment concentration contained in the color filter pattern material is increased, the light necessary for the photocuring reaction does not reach the bottom of the color filter pattern layer, and the curing of the color filter layer becomes insufficient. For this reason, there is a problem that the layer of the color filter is peeled off in the developing step in photolithography to generate a pixel defect.
　また、色フィルターの膜厚を薄くし且つ分光特性を得るために、色フィルター用材料に含まれる顔料濃度を上げた場合、相対的に光硬化成分を低減させることになる。このため、色フィルターの層の光硬化が不十分となり、色フィルターの形状の悪化、面内での色フィルターの形状不均一、色フィルターの形状崩れ等が発生しやすくなる。また、色フィルターの層を十分に光硬化させるために硬化時の露光量を多くすることで、スループットが低下するという問題が発生する。 In addition, when the pigment concentration contained in the color filter material is increased in order to reduce the thickness of the color filter and obtain spectral characteristics, the light curing component is relatively reduced. For this reason, the light curing of the layer of the color filter is insufficient, and the shape of the color filter is deteriorated, the shape nonuniformity of the color filter in the plane, the shape collapse of the color filter, and the like easily occur. In addition, there is a problem that the throughput is reduced by increasing the exposure amount at the time of curing in order to sufficiently photocure the layer of the color filter.
　色フィルターパターンの高精細化により、色フィルターパターンの膜厚は、製造工程上の問題だけではなく、固体撮像素子としての特性にも影響する。色フィルターパターンの膜厚が厚い場合、斜め方向から入射した光が特定色フィルターによって分光されたのち、隣接する他の色フィルターパターン部及び光電変換素子に入光する場合がある。この場合、混色が生じてしまう問題が発生する。この混色の問題は、色フィルターパターンの画素サイズが小さくなり、画素サイズと膜厚とのアスペクト比が大きくなるにつれて顕著になる。また、入射光の混色という問題は、光電変換素子が形成された基板上に平坦化層等の材料を形成することで、色フィルターパターンと光電変換素子との距離が長くなる場合にも顕著に生じる。このため、色フィルターパターンやその下部に形成される平坦化層等の膜厚の薄膜化が重要となる。 Due to the high definition of the color filter pattern, the film thickness of the color filter pattern affects not only the problem in the manufacturing process but also the characteristics as a solid-state imaging device. When the film thickness of the color filter pattern is large, light incident from an oblique direction may be split by the specific color filter and then may enter the adjacent other color filter pattern portion and photoelectric conversion element. In this case, there arises a problem that color mixing occurs. The problem of color mixture becomes significant as the pixel size of the color filter pattern decreases and the aspect ratio between the pixel size and the film thickness increases. In addition, the problem of color mixing of incident light is remarkable even when the distance between the color filter pattern and the photoelectric conversion element is increased by forming a material such as a planarization layer on a substrate on which the photoelectric conversion element is formed. It occurs. For this reason, it is important to reduce the thickness of the color filter pattern and the planarizing layer formed therebelow.
　斜め方向からの入射等による混色防止のために、各色のカラーフィルタの間に光を反射や屈折させ、他の画素に入射する光を遮る隔壁を形成する方法が知られている。液晶ディスプレイ等の光学表示デバイスに用いられるカラーフィルタでは、黒色の材料によるブラックマトリクス（ＢＭ）構造による隔壁が一般的に知られている。しかし、固体撮像素子の場合、各カラーフィルタパターンのサイズが数μｍ以下である。このため、一般的なブラックマトリクスの形成方法を用いて隔壁を形成した場合、パターンサイズが大きい為、画素欠陥のように一部の画素がＢＭで塗りつぶされてしまい解像性が低下してしまう。 There is known a method of reflecting or refracting light between color filters of each color and forming a partition that blocks light incident on other pixels in order to prevent color mixing due to oblique incidence or the like. In color filters used for optical display devices such as liquid crystal displays, partitions having a black matrix (BM) structure of a black material are generally known. However, in the case of a solid-state imaging device, the size of each color filter pattern is several μm or less. For this reason, when the partition is formed using a general black matrix formation method, some pixels are painted with BM like a pixel defect because the pattern size is large, and the resolution is lowered. .
　高精細化が進んでいる固体撮像素子の場合、求められる隔壁のサイズは数百ｎｍサイズ、より好ましくは幅２００ｎｍ以下程度であり、一つの画素サイズが１μｍ程度となるまで画素サイズの高精細化が進んでいる。この為、混色を抑制できる遮光性能を満たせるのであれば、１００ｎｍ以下の幅(寸法)が望ましい。このサイズの隔壁形成には、ＢＭを用いたフォトリソグラフィ法では困難である。このため、アルミニウム、タングステン、チタンなどの金属やＳｉＯ２等の無機物やこれらを複合させて用い、蒸着、ＣＶＤ、スパッタ等による成膜や、エッチング技術を用いて格子パターン上に削ることによって形成する方法で隔壁が形成されている。しかしながら、このような方法では、製造装置や製造工程の複雑化等で製造コストが非常に高価となってしまうという問題がある。 In the case of solid-state imaging devices in which high definition is in progress, the size of the partition required is several hundred nm, more preferably about 200 nm or less in width, and high definition of pixel size is achieved until one pixel size becomes about 1 μm. Is advancing. For this reason, if the light shielding performance capable of suppressing color mixing can be satisfied, a width (dimension) of 100 nm or less is desirable. It is difficult to form partition walls of this size by photolithography using a BM. For this reason, it is formed by forming a film by vapor deposition, CVD, sputtering or the like, or scraping it on a lattice pattern using an etching technique, using a metal such as aluminum, tungsten, titanium or an inorganic substance such as SiO 2 or a compound thereof. The partition wall is formed by the method. However, such a method has a problem that the manufacturing cost becomes very expensive due to the complication of the manufacturing apparatus and the manufacturing process.
　以上のことから、固体撮像素子の画素数を増やすためには、色フィルター層のパターンの高精細化が必要であり、色フィルター層の薄膜化や混色防止方法が重要となる。 From the above, in order to increase the number of pixels of the solid-state imaging device, it is necessary to make the pattern of the color filter layer highly precise, and it is important to make the color filter layer thinner and to prevent color mixing.
　上述のように、従来の、色フィルター材料に感光性を持たせてフォトリソグラフィにより形成される色フィルター層のパターン形成は、画素の寸法の微細化が進むにつれて、色フィルター層の膜厚の薄膜化も求められる。この場合、色フィルター材料中の顔料成分の含有割合が増えることから、感光性成分を十分な量含有できず、解像性が得られない、残渣が残りやすい、画素剥がれが生じやすいという問題があり、固体撮像素子の特性を低下させる課題があった。 As described above, in the conventional pattern formation of a color filter layer formed by photolithography by giving color sensitivity to a color filter material, a thin film of the thickness of the color filter layer is formed as the pixel size is further reduced. Are also required. In this case, since the content ratio of the pigment component in the color filter material increases, the photosensitive component can not be contained in a sufficient amount, resolution can not be obtained, residue tends to remain, and pixel peeling easily occurs. There is a problem of lowering the characteristics of the solid-state imaging device.
　そこで、色フィルターパターンの微細化及び薄膜化を行うために、特許文献２の技術が提案されている。特許文献２には、色フィルター用材料中の顔料濃度を向上できるように、感光性成分を含有しなくてもパターニングが可能なドライエッチングにより色フィルターパターンを形成することが記載されている。これらのドライエッチングを用いる技術により、顔料濃度を向上させることが可能となり、薄膜化を行っても十分な分光特性を得られる色フィルターパターンが作製可能となる。 Therefore, in order to miniaturize and thin the color filter pattern, the technique of Patent Document 2 has been proposed. Patent Document 2 describes that a color filter pattern is formed by dry etching that can be patterned without containing a photosensitive component so that the pigment concentration in the color filter material can be improved. These techniques of using dry etching make it possible to improve the pigment concentration, and it is possible to produce a color filter pattern that can obtain sufficient spectral characteristics even when the film is thinned.
特開平１１－６８０７６号公報Japanese Patent Application Laid-Open No. 11-68076 特許第４９０５７６０号公報Patent No. 4905760
　しかしながら、発明者らが、特許文献２に記載の色フィルターパターンの製造方法を検討したところ各色フィルターの膜厚の関係が示されておらず、全ての色フィルターで高感度化できない場合があることを知見した。また、混色に対する対策も不十分であることを知見した。また、各色フィルターパターンをドライエッチングで形成する際、色フィルター材は有機物と金属を含有した材料であることから、ドライエッチングでの形状加工は困難であり残渣が残りやすく、また残渣が発生しないように時間を長くドライエッチングを行う場合は、光電変換素子にプラズマダメージを与えやすいという知見を得た。 However, when the inventors examined the manufacturing method of the color filter pattern described in Patent Document 2, the relationship between the film thickness of each color filter is not shown, and in some cases, it may not be possible to achieve high sensitivity with all color filters. Found out. We also found that measures against color mixing were inadequate. In addition, when forming each color filter pattern by dry etching, since the color filter material is a material containing an organic substance and a metal, shape processing in dry etching is difficult, residue tends to remain, and no residue is generated. In the case where dry etching is performed for a long time, it has been found that the photoelectric conversion element is easily damaged by plasma.
　本発明は、上述のような点に鑑みてなされたものであって、混色を抑制し、プラズマダメージを低減し、高精細で感度の良い固体撮像素子を提供することを目的とする。 The present invention has been made in view of the above-described points, and it is an object of the present invention to provide a solid-state imaging device having high definition and high sensitivity by suppressing color mixing, reducing plasma damage.
　本発明の一態様による固体撮像素子は、複数の光電変換素子を二次元的に配置した半導体基板と、上記半導体基板上に形成され、上記複数の光電変換素子に対応させて複数色の色フィルターを予め設定した規則パターンで二次元的に配置した色フィルター層と、上記複数色から選択した第１の色の色フィルターと半導体基板との間に配置された透明導電層と、を備えることを特徴する。 A solid-state imaging device according to an aspect of the present invention includes a semiconductor substrate on which a plurality of photoelectric conversion devices are two-dimensionally arranged, and a color filter formed on the semiconductor substrate and corresponding to the plurality of photoelectric conversion devices. Providing a color filter layer two-dimensionally arranged in a predetermined regular pattern, and a transparent conductive layer disposed between the color filter of the first color selected from the plurality of colors and the semiconductor substrate. To feature.
　上記透明導電層のシート抵抗をＦとした場合に下記（１）式を満足してもよい。
　Ｆ＜１０００００　Ω／□　・・・（１） When the sheet resistance of the transparent conductive layer is F, the following formula (1) may be satisfied.
F <100000 Ω / □ (1)
　上記透明導電層は、珪素、炭素、酸素、水素、錫、亜鉛、インジウム、アルミニウム、ガリウム、チタン、モリブデン、タングステン、カドミウム、ニオブ、タンタル、ハフニウム、銀、フッ素から選ばれる少なくとも１種類を含有する化合物が単層又は複層で形成されていてもよい。 The transparent conductive layer contains at least one selected from silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine. The compound may be formed in a single layer or multiple layers.
　上記透明導電層及び上記第１の色の色フィルターは、上記透明導電層のエッチングレートをＴとし、上記第１の色の色フィルターのエッチングレートをＧとしたとき、フッ素、酸素、水素、硫黄、炭素、臭素、塩素、窒素、アルゴン、ヘリウム、キセノン、クリプトンから選ばれる少なくとも１種類を含有するガスを用いたドライエッチングにおいて、下記（２）式を満足する材料構成となっていてもよい。
　３≦Ｇ／Ｔ　　・・・（２） When the transparent conductive layer and the color filter of the first color have an etching rate of the transparent conductive layer as T and an etching rate of the color filter of the first color as G, fluorine, oxygen, hydrogen, sulfur In dry etching using a gas containing at least one selected from carbon, bromine, chlorine, nitrogen, argon, helium, xenon, and krypton, the material configuration may satisfy the following formula (2).
3 ≦ G / T (2)
　上記複数色の色フィルターの間に配置した隔壁を更に備えていてもよい。 You may further provide the partition arrange | positioned between the said color filter of multiple colors.
　上記隔壁は、亜鉛、銅、ニッケル、珪素、炭素、酸素、水素、窒素、臭素、塩素、インジウム、錫から選ばれる少なくとも１種類を含有していてもよい。 The partition wall may contain at least one selected from zinc, copper, nickel, silicon, carbon, oxygen, hydrogen, nitrogen, bromine, chlorine, indium and tin.
　上記第１の色の色フィルターの膜厚をＡ［ｎｍ］、上記透明導電層の膜厚をＢ［ｎｍ］、上記第１の色以外の色の色フィルターの膜厚をＣ［ｎｍ］、上記透明導電層の可視光の透過率をＤ［％］、上記隔壁の寸法をＥ［ｎｍ］とした場合に、下記（３）～（７）式を満足してもよい。
　２００［ｎｍ］≦Ａ≦７００［ｎｍ］　　　　　　　　　・・・（３）
　０［ｎｍ］＜Ｂ≦２００［ｎｍ］　　　　　　　　　　　・・・（４）
　Ａ＋Ｂ－２００［ｎｍ］≦Ｃ≦Ａ＋Ｂ＋２００［ｎｍ］　・・・（５）
　Ｄ≧８０［％］・・・（６）
　Ｅ≦２００［ｎｍ］・・・（７） The film thickness of the first color filter is A [nm], the film thickness of the transparent conductive layer is B [nm], the film thickness of color filters of colors other than the first color is C [nm], When the visible light transmittance of the transparent conductive layer is D [%] and the dimension of the partition is E [nm], the following formulas (3) to (7) may be satisfied.
200 [nm] ≦ A ≦ 700 [nm] (3)
0 [nm] <B ≦ 200 [nm] (4)
A + B-200 [nm] ≦ C ≦ A + B + 200 [nm] (5)
D 80 80 [%] (6)
E ≦ 200 [nm] (7)
　上記透明導電層と上記第１の色の色フィルターとの間に、更に透明樹脂層を備えていてもよい。 A transparent resin layer may be further provided between the transparent conductive layer and the color filter of the first color.
　上記透明導電層と上記半導体基板との間に、更に透明樹脂層を備えていてもよい。 A transparent resin layer may be further provided between the transparent conductive layer and the semiconductor substrate.
　上記透明樹脂層は、珪素、炭素、酸素、水素から選ばれる少なくとも１種類を含有してもよい。 The transparent resin layer may contain at least one selected from silicon, carbon, oxygen, and hydrogen.
　上記第１の色の色フィルターには、熱硬化性樹脂を含有してもよい。 The first color filter may contain a thermosetting resin.
　上記第１の色の色フィルターには、熱硬化性樹脂及び光硬化性樹脂を含有し、光硬化性樹脂の含有量よりも熱硬化性樹脂の含有量の方が多くてもよい。 The color filter of the first color may contain a thermosetting resin and a photocurable resin, and the content of the thermosetting resin may be larger than the content of the photocurable resin.
　上記第１の色の色フィルターには、光硬化性樹脂を含有してもよい。 The color filter of the first color may contain a photocurable resin.
　上記第１の色の色フィルターは、着色剤である顔料の濃度が５０質量％以上であってもよい。 The color filter of the first color may have a concentration of the pigment as the colorant of 50% by mass or more.
　上記色フィルター層上に、上記光電変換素子のそれぞれに対応して二次元的に配置されたマイクロレンズを有し、上記マイクロレンズのレンズトップからレンズボトムまでの高さが３００ｎｍ以上８００ｎｍ以下の範囲であってもよい。 A microlens having a two-dimensional arrangement corresponding to each of the photoelectric conversion elements is provided on the color filter layer, and the height from the lens top to the lens bottom of the microlens ranges from 300 nm to 800 nm. It may be
　上記複数色の色フィルターのうち、上記第１の色の色フィルターの専有面積が一番広くてもよい。 Among the color filters of the plurality of colors, the area occupied by the color filter of the first color may be the largest.
　本発明の一態様による固体撮像素子の製造方法は、複数の光電変換素子を二次元的に配置した半導体基板に透明導電層を形成し、上記透明導電層上に第１の色の色フィルター用の塗布液を塗布し硬化させて透明導電層及び第１の色の色フィルター層をこの順に形成した後、上記第１の色の色フィルターの配置位置以外の上記第１の色の色フィルター層部分をドライエッチングによって除去して第１の色の色フィルターをパターン形成する第１の工程と、上記第１の色の色フィルターをパターン形成する第１の工程において、上記第１の色の色フィルター層をドライエッチングする際に生じる色フィルター層とドライエッチングガスの副生成物を、上記第１の色の色フィルターの側壁に隔壁として形成する第２の工程と、第２の工程後に、第１の色の以外の色の色フィルターを、フォトリソグラフィによってパターニングして形成する第３の工程と、を備えることを特徴とする。 In a method of manufacturing a solid-state imaging device according to an aspect of the present invention, a transparent conductive layer is formed on a semiconductor substrate in which a plurality of photoelectric conversion devices are two-dimensionally arranged, and a first color color filter is formed on the transparent conductive layer. The coating solution is applied and cured to form the transparent conductive layer and the color filter layer of the first color in this order, and then the color filter layer of the first color other than the arrangement position of the color filter of the first color The color of the first color in the first step of patterning the first color filter by removing the portion by dry etching and the first step of patterning the first color filter; A second step of forming a color filter layer and a by-product of a dry etching gas generated during dry etching of the filter layer as a partition on the side wall of the first color filter, and after the second step, Color color filters of other colors, characterized in that it comprises a third step of forming and patterning by photolithography, a.
　本発明の他の態様による固体撮像素子の製造方法は、複数の光電変換素子を二次元的に配置した半導体基板に透明導電層を形成し、上記透明導電層上に透明樹脂層を形成し、第１の色の色フィルター用の塗布液を塗布し硬化させて、透明導電層、透明樹脂層及び第１の色の色フィルター層をこの順に形成した後、第１の色の色フィルターの配置位置以外の上記第１の色の色フィルター層部分及び該第１の色の色フィルター層部分の下層に位置する透明樹脂層をドライエッチングによって除去して第１の色の色フィルターをパターン形成する第１の工程と、上記第１の色の色フィルターをパターン形成する第１の工程において、上記第１の色の色フィルター層及びその除去する色フィルター層部分の下層に位置する透明樹脂層をドライエッチングする際に生じる色フィルター層及び透明樹脂層とドライエッチングガスの副生成物を、上記第１の色の色フィルターの側壁に隔壁として形成する第２の工程と、第２の工程後に、第１の色の以外の色の色フィルターを、フォトリソグラフィによってパターニングして形成する第３の工程と、を備えることを特徴とする。 In a method of manufacturing a solid-state imaging device according to another aspect of the present invention, a transparent conductive layer is formed on a semiconductor substrate in which a plurality of photoelectric conversion devices are two-dimensionally arranged, and a transparent resin layer is formed on the transparent conductive layer. A coating solution for a first color filter is applied and cured to form a transparent conductive layer, a transparent resin layer, and a first color filter layer in this order, and then the arrangement of the first color filter The color filter layer portion of the first color other than the position and the transparent resin layer located under the first color filter layer portion are removed by dry etching to pattern the first color color filter In the first step and the first step of patterning the color filter of the first color, the transparent resin layer positioned under the color filter layer of the first color and the color filter layer portion to be removed is used. Dry etch Forming a color filter layer, a transparent resin layer, and a by-product of a dry etching gas, which are generated during printing, as partition walls on the side walls of the color filter of the first color; And a third step of forming and patterning a color filter of a color other than one by photolithography.
　上記第１の色の色フィルターの硬化時の加熱温度が１７０℃以上２７０℃以下であってもよい。 The heating temperature at the time of curing of the color filter of the first color may be 170 ° C. or more and 270 ° C. or less.
　本発明の各態様によれば、各色フィルターの薄膜化及び色フィルター間の隔壁によって、混色を抑制でき、ドライエッチングによるプラズマダメージがなく、パターン配置した全ての色フィルターが高感度化した高精細な固体撮像素子を提供することが可能となる。 According to each aspect of the present invention, color mixing can be suppressed by the thinning of the color filters and the partitions between the color filters, and there is no plasma damage due to dry etching and high definition in which all the color filters arranged in pattern have high sensitivity. It becomes possible to provide a solid-state imaging device.
本発明の第１の実施形態に係る固体撮像素子の部分断面図である。It is a fragmentary sectional view of a solid-state image sensing device concerning a 1st embodiment of the present invention. 本発明の第１の実施形態に係る固体撮像素子の色フィルター配列の部分平面図である。FIG. 2 is a partial plan view of a color filter array of a solid-state imaging device according to a first embodiment of the present invention. 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、透明導電層形成工程から第１の色の色フィルター加熱硬化工程までを示す図である。It is a manufacturing-process sectional view of the solid-state image sensor concerning a 1st embodiment of the present invention, and is a figure showing from a transparent conductive layer formation process to a color filter heat-hardening process of the 1st color. 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、感光性樹脂材料塗布工程から第１の色の色フィルター層の現像工程までを示す図である。FIG. 6A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from a photosensitive resin material application process to a developing process of a first color filter layer; 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、第１の色の色フィルター層の一部をドライエッチングする工程からエッチングマスク除去工程までを示す図である。FIG. 6A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from dry etching a part of the first color filter layer to an etching mask removing process; 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、第２の色の色フィルター塗布工程から第２の色の色フィルターの加熱硬化までを示す図である。FIG. 7A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from a second color filter application process to heat curing of the second color filter; 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、第３の色の色フィルター塗布工程から第３の色の色フィルターの加熱硬化工程までを示す図である。FIG. 7A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process from a third color filter application process to a heat curing process for the third color filter. 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、平坦化層形成工程及びマイクロレンズ形成工程を示す図である。FIG. 5A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, and is a view showing a planarizing layer forming process and a microlens forming process. 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、平坦化層形成工程からマイクロレンズ母型層形成工程を示す図である。FIG. 5A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a process of forming a planarizing layer to a process of forming a microlens matrix layer; 本発明の第１の実施形態に係る固体撮像素子の製造工程断面図であって、マイクロレンズ母型形成工程からレンズ転写工程を示す図である。FIG. 5A is a manufacturing process sectional view of the solid-state imaging device according to the first embodiment of the present invention, showing a lens matrix forming process to a lens transferring process. 本発明の第２の実施形態に係る固体撮像素子の部分断面図である。It is a fragmentary sectional view of the solid-state image sensor concerning a 2nd embodiment of the present invention. 本発明の第２の実施形態に係る固体撮像素子の製造工程断面図であって、透明導電層形成工程から感光性樹脂材料塗布工程までを示す図である。It is manufacturing-process sectional drawing of the solid-state image sensor which concerns on the 2nd Embodiment of this invention, Comprising: It is a figure which shows from a transparent conductive layer formation process to the photosensitive resin material application process. 本発明の第２の実施形態に係る固体撮像素子の製造工程断面図であって、感光性樹脂材料露光工程から第１の色の色フィルター層の現像工程までを示す図である。It is a manufacturing process sectional view of a solid-state imaging device concerning a 2nd embodiment of the present invention, and is a figure showing from a photosensitive resin material exposure process to a development process of a color filter layer of the 1st color. 本発明の第２の実施形態に係る固体撮像素子の製造工程断面図であって、第１の色の色フィルター層の一部をドライエッチングする工程からエッチングマスク除去工程までを示す図である。FIG. 7A is a manufacturing process sectional view of the solid-state imaging device according to the second embodiment of the present invention, showing a process from dry etching a part of the first color filter layer to an etching mask removing process; 本発明の第３の実施形態に係る固体撮像素子の部分断面図である。It is a fragmentary sectional view of the solid-state image sensor concerning a 3rd embodiment of the present invention. 本発明の第３の実施形態に係る固体撮像素子の製造工程断面図であって、透明樹脂層形成工程から感光性樹脂材料塗布工程までを示す図である。It is manufacturing-process sectional drawing of the solid-state image sensor which concerns on the 3rd Embodiment of this invention, Comprising: It is a figure which shows from a transparent resin layer formation process to the photosensitive resin material application process. 本発明の第３の実施形態に係る固体撮像素子の製造工程断面図であって、感光性樹脂材料露光工程から第１の色の色フィルター層の現像工程までを示す図である。It is manufacturing-process sectional drawing of the solid-state image sensor which concerns on the 3rd Embodiment of this invention, Comprising: It is a figure which shows from the photosensitive resin material exposure process to the development process of the color filter layer of 1st color. 本発明の第３の実施形態に係る固体撮像素子の製造工程断面図であって、第１の色の色フィルター層の一部をドライエッチングする工程からエッチングマスク除去工程までを示す図である。FIG. 14A is a manufacturing process sectional view of the solid-state imaging device according to the third embodiment of the present invention, showing a process from dry etching a part of the first color filter layer to an etching mask removing process;
　以下、本発明の実施形態について図面を参照しながら説明する。
　ここで、図面は模式的なものであり、色フィルターなどの高さ（厚み）と平面寸法との関係、各層の高さ（厚み）の比率等は現実のものとは異なる。また、以下に示す各実施形態は、本発明の技術的思想を具体化するための構成を例示するものであって、本発明の技術的思想は、構成部品の材質、形状、構造等が下記のものに特定されるものでない。本発明の技術的思想は、特許請求の範囲に記載された請求項が規定する技術的範囲内において、種々の変更を加えることができる。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Here, the drawings are schematic, and the relationship between the height (thickness) of the color filter etc. and the planar dimension, the ratio of the height (thickness) of each layer, etc. are different from the actual ones. In addition, each embodiment shown below exemplifies the configuration for embodying the technical idea of the present invention, and the technical idea of the present invention is that the material, shape, structure and the like of the component parts are as follows. It is not something specific to The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.
　「第１の実施形態」
　＜固体撮像素子の構成＞
　本実施形態に係る固体撮像素子１は、図１に示すように、二次元的に配置された複数の光電変換素子１１を有する半導体基板１０と、半導体基板１０の上方に配置された複数のマイクロレンズ１８からなるマイクロレンズ群１０８と、半導体基板１０とマイクロレンズ１８との間に設けられた色フィルター層１００及び隔壁１７とを備えている。色フィルター層１００は、複数色の各色フィルター１４，１５，１６が所定の規則パターンで配置されて構成される。隔壁１７は、複数色の各色フィルター１４，１５，１６のそれぞれの間に構成される。 "First embodiment"
<Configuration of solid-state imaging device>
As shown in FIG. 1, the solid-state imaging device 1 according to the present embodiment includes a semiconductor substrate 10 having a plurality of photoelectric conversion elements 11 two-dimensionally arranged, and a plurality of micro-elements disposed above the semiconductor substrate 10. The micro lens group 108 including the lens 18 and the color filter layer 100 and the partition wall 17 provided between the semiconductor substrate 10 and the micro lens 18 are provided. The color filter layer 100 is configured by arranging the color filters 14, 15, 16 of a plurality of colors in a predetermined regular pattern. The partition wall 17 is formed between each of the color filters 14, 15, 16 of a plurality of colors.
　図１は、色フィルター層１００の下部に透明導電層１２がある構成の固体撮像素子１を示している。また、色フィルター層１００と複数のマイクロレンズ１８からなるマイクロレンズ群１８０との間に、平坦化層１３が形成されている。平坦化層１３は、後述するエッチバック方式のようにマイクロレンズ１８と同化している場合は無くても良い。 FIG. 1 shows the solid-state imaging device 1 having a configuration in which the transparent conductive layer 12 is located below the color filter layer 100. Further, the flattening layer 13 is formed between the color filter layer 100 and the microlens group 180 including the plurality of microlenses 18. The planarizing layer 13 may not be the same as the microlens 18 as in an etch back method described later.
　以下、本実施形態に係る固体撮像素子１の説明にあたり、製造工程上最初に形成する、最も面積が広い色フィルターを第１の色の色フィルター１４と定義する。また、製造工程上二番目に形成する色フィルターを第２の色の色フィルター１５、製造工程上三番目に形成する色フィルターを第３の色の色フィルター１６と定義する。他の実施形態であっても同様である。すなわち、本実施形態及び他の実施形態では、複数の色の色フィルターの一例である第１の色の色フィルター１４、第２の色の色フィルター１５及び第３の色の色フィルター１６のうち、第１の色の色フィルター１４の専有面積が一番広く構成されている。 Hereinafter, in the description of the solid-state imaging device 1 according to the present embodiment, the color filter with the largest area, which is formed first in the manufacturing process, is defined as the color filter 14 of the first color. Further, the color filter formed second in the manufacturing process is defined as the color filter 15 of the second color, and the color filter formed third in the manufacturing process is defined as the color filter 16 of the third color. The same applies to the other embodiments. That is, in the present embodiment and the other embodiments, among the color filters 14 of the first color, the color filters 15 of the second color, and the color filters 16 of the third color, which are an example of color filters of a plurality of colors. The area occupied by the first color filter 14 is the widest.
　本実施形態に係る固体撮像素子１では、第１の色の色フィルター１４には、熱硬化性樹脂と光硬化性樹脂が含まれている。光硬化性樹脂の含有量は、熱硬化性樹脂の含有量よりも少ない。ここで、第１の色の色フィルター１４は、最も面積が広い色フィルターで無くとも良く、また一番初めに形成される色フィルターで無くても良い。また本実施形態では、色フィルター層１００が、複数色のグリーン、ブルー、レッドの３色から構成され、ベイヤー配列の配置パターンで配置される場合で例示するが、４色以上からなる色フィルター層であってもよい。以下の説明では、第１の色がグリーンの場合を想定して説明するが、第１の色がブルー又はレッドであっても良い。
　以下、固体撮像素子の各部について詳細に説明する。 In the solid-state imaging device 1 according to the present embodiment, the color filter 14 of the first color contains a thermosetting resin and a photocurable resin. The content of the photocurable resin is less than the content of the thermosetting resin. Here, the color filter 14 of the first color may not be the color filter with the largest area, and may not be the color filter formed first. In this embodiment, the color filter layer 100 is composed of three colors of green, blue and red of multiple colors and is arranged in the arrangement pattern of the Bayer array, but the color filter layer consisting of four or more colors is exemplified. It may be In the following description, the first color is assumed to be green, but the first color may be blue or red.
Hereinafter, each part of the solid-state imaging device will be described in detail.
（光電変換素子及び半導体基板）
　半導体基板１０は、画素に対応させて複数の光電変換素子１１が二次元的に配置されている。複数の光電変換素子１１は、光を電気信号に変換する機能を有している。
　光電変換素子１１が形成されている半導体基板１０は、通常、表面（光入射面）の保護及び平坦化を目的として、最表面に保護膜が形成されている。半導体基板１０は、可視光を透過して、少なくとも３００℃程度の温度に耐えられる材料で形成されている。このような材料としては、例えば、Ｓｉ、ＳｉＯ２等の酸化物及びＳｉＮ等の窒化物、並びにこれらの混合物等、Ｓｉを含む材料等が挙げられる。 (Photoelectric conversion element and semiconductor substrate)
In the semiconductor substrate 10, a plurality of photoelectric conversion elements 11 are two-dimensionally arranged corresponding to pixels. The plurality of photoelectric conversion elements 11 have a function of converting light into an electrical signal.
In general, a protective film is formed on the outermost surface of the semiconductor substrate 10 on which the photoelectric conversion element 11 is formed, for the purpose of protecting and planarizing the surface (light incident surface). The semiconductor substrate 10 is formed of a material that transmits visible light and can withstand a temperature of at least about 300.degree. Examples of such a material include Si, oxides such as SiO 2 , nitrides such as SiN, and mixtures thereof, materials containing Si, and the like.
（マイクロレンズ）
　各マイクロレンズ１８は、画素位置に対応させて、半導体基板１０の上方に配置されている。すなわち、マイクロレンズ１８は、半導体基板１０に形成された色フィルター層１００上に、二次元配置された複数の光電変換素子１１毎に設けられる。マイクロレンズ１８は、マイクロレンズ１８に入射した入射光を光電変換素子１１のそれぞれに集光させることにより、光電変換素子１１の感度低下を補う。
　マイクロレンズ１８は、レンズトップからレンズボトムの高さが３００ｎｍ以上８００ｎｍ以下の範囲であることが好ましい。 (Micro lens)
Each microlens 18 is disposed above the semiconductor substrate 10 in correspondence with the pixel position. That is, the microlenses 18 are provided on each of the plurality of two-dimensionally arranged photoelectric conversion elements 11 on the color filter layer 100 formed on the semiconductor substrate 10. The microlens 18 condenses the incident light incident on the microlens 18 on each of the photoelectric conversion elements 11 to compensate for the decrease in sensitivity of the photoelectric conversion elements 11.
The microlens 18 preferably has a height of 300 nm or more and 800 nm or less from the lens top to the lens bottom.
（透明導電層）
　透明導電層１２は、半導体基板１０の表面保護、平坦化及び、プラズマエッチングによる帯電（チャージアップ）等のダメージ低減のために設けられた層である。すなわち、透明導電層１２は、光電変換素子１１の作製による半導体基板１０の上面の凹凸を低減し、色フィルター用材料との密着性を向上させ、第１の色の色フィルターをパターン加工する際のプラズマエッチングの保護層となる。 (Transparent conductive layer)
The transparent conductive layer 12 is a layer provided for surface protection of the semiconductor substrate 10, planarization, and damage reduction such as charging (charge up) by plasma etching. That is, when the transparent conductive layer 12 reduces unevenness on the upper surface of the semiconductor substrate 10 by the preparation of the photoelectric conversion element 11, improves the adhesion with the color filter material, and patterns the color filter of the first color. It becomes a protective layer of plasma etching.
　透明導電層１２は、例えば珪素、炭素、酸素、水素、錫、亜鉛、インジウム、アルミニウム、ガリウム、チタン、モリブデン、タングステン、カドミウム、ニオブ、タンタル、ハフニウム、銀、フッ素から選ばれる少なくとも１種類を含有する化合物や酸化物が単層又は複層で形成される。これらの材料の化合物としては、たとえばＩＴＯやＺｎＯ、ＴｉＯ２、ＨｆＯ２などの透明導電層を用いることができる。また、透明導電層１２は、これらの酸化物や化合物に限らず、波長が４００ｎｍから７００ｎｍの可視光を透過し、色フィルター１４、１５、１６のパターン形成や密着性を阻害しない材料であれば、いずれを用いて形成することができる。透明導電層１２は、色フィルター１４，１５，１６の分光特性に影響を与えないことが好ましい。例えば、透明導電層１２は、波長が４００ｎｍから７００ｎｍの可視光に対して透過率８０％以上であり、より好ましくは透過率９０％以上となるように形成されることが好ましい。 The transparent conductive layer 12 contains, for example, at least one selected from silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine. Compounds or oxides are formed in a single layer or multiple layers. As a compound of these materials, for example, a transparent conductive layer of ITO, ZnO, TiO 2 , HfO 2 or the like can be used. In addition, the transparent conductive layer 12 is not limited to these oxides and compounds, as long as it is a material that transmits visible light having a wavelength of 400 nm to 700 nm and does not inhibit the pattern formation or adhesion of the color filters 14, 15, 16. Any of these can be used. The transparent conductive layer 12 preferably does not affect the spectral characteristics of the color filters 14, 15, 16. For example, the transparent conductive layer 12 is preferably formed to have a transmittance of 80% or more, more preferably 90% or more, to visible light having a wavelength of 400 nm to 700 nm.
　透明導電層１２のシート抵抗率は１０００００Ω／ｓｑ．より低い、所謂導電性がある物質であることが好ましい。特に一般的に使用されている透明導電層として、５０００Ω／ｓｑ．以下である事が好ましく、透明導電層としてより望ましくは１５００Ω／ｓｑ．以下であり、より好ましくは８００Ω／ｓｑ．以下である。これらのシート抵抗を得られる透明導電層１２は、上記に記載した材料で形成される。例えば、透明導電層１２としてＩＴＯを用いた場合は、シート抵抗が５０Ω／ｓｑ．以下も形成可能である。またＺｎＯにＡｌやＧａをドープした透明導電膜などでも同様のシート抵抗を得られる。 The sheet resistivity of the transparent conductive layer 12 is 100,000 Ω / sq. It is preferable that the substance be a substance having a lower conductivity. In particular, 5000 Ω / sq. Or less, and more preferably 1500 Ω / sq. Or less, more preferably 800 Ω / sq. It is below. The transparent conductive layer 12 capable of obtaining these sheet resistances is formed of the materials described above. For example, when ITO is used as the transparent conductive layer 12, the sheet resistance is 50 Ω / sq. The following can also be formed. The same sheet resistance can be obtained also by using a transparent conductive film in which ZnO is doped with Al or Ga.
　また上記透明導電層１２は、ドライエッチングのプラズマダメージを低減する目的の為、エッチングレートが遅い化合物で構成されていることが好ましい。その為、透明導電層１２のエッチングレートが色フィルター１４のエッチングレートよりも遅い条件となる材料構成となっていることが望ましい。ドライエッチングで使用するガスとしてフッ素、酸素、硫黄、炭素、臭素、塩素、アルゴン、ヘリウム、キセノン、クリプトンから選ばれる少なくとも１種類を含有するガスを用いたドライエッチングにおいて、透明導電層１２のエッチングレート（Ｇ）が色フィルター１４のエッチングレート（Ｔ）よりも３倍以上遅い（３≦Ｇ／Ｔ）ことが好ましく、より好ましくは１０倍以上遅い条件である。具体的には、透明導電層１２にＩＴＯ膜を用いて、ドライエッチングガスにフッ素、炭素、酸素を含んだガスを用いてドライエッチングを実施した場合は、ＩＴＯ膜のエッチングがほぼ進行せず、色フィルター１４よりもエッチングレートが２０倍以上遅い条件となり、エッチングレートの設定を満足する。 The transparent conductive layer 12 is preferably made of a compound having a slow etching rate for the purpose of reducing plasma damage in dry etching. Therefore, it is desirable that the material configuration be such that the etching rate of the transparent conductive layer 12 is slower than the etching rate of the color filter 14. In dry etching using a gas containing at least one selected from fluorine, oxygen, sulfur, carbon, bromine, chlorine, argon, helium, xenon, krypton as a gas used in dry etching, the etching rate of transparent conductive layer 12 It is preferable that (G) is 3 times or more slower (3 ≦ G / T) than the etching rate (T) of the color filter 14, and more preferably 10 times or more slower. Specifically, when the ITO film is used for the transparent conductive layer 12 and the dry etching is performed using the gas containing fluorine, carbon and oxygen as the dry etching gas, the etching of the ITO film hardly progresses. The etching rate is 20 times or more slower than that of the color filter 14, and the setting of the etching rate is satisfied.
　また、透明導電層１２は透過率を満たせるなら、Ａｇを用いたナノインク、無機酸化物を用いたナノＩＴＯのような粒子の凝集物、カーボンナノチューブインク、導電性高分子などの透明樹脂を用いても良い。 In addition, if the transparent conductive layer 12 can satisfy the transmittance, it is preferable to use a transparent resin such as nano ink using Ag, particle aggregate such as nano ITO using inorganic oxide, carbon nanotube ink, conductive polymer, etc. Also good.
　本実施形態では、透明導電層１２の膜厚Ｂ［ｎｍ］を、０［ｎｍ］より大きく２００［ｎｍ］以下に形成する。透明導電層１２の膜厚Ｂは、透過率、混色防止の観点からは薄いほど好ましく、５ｎｍ以上８０ｎｍ以下がより好ましい。 In the present embodiment, the film thickness B [nm] of the transparent conductive layer 12 is formed to be more than 0 [nm] and 200 [nm] or less. The film thickness B of the transparent conductive layer 12 is preferably as thin as possible from the viewpoint of transmittance and color mixing prevention, and is more preferably 5 nm or more and 80 nm or less.
（平坦化層）
　平坦化層１３は、第１から第３の色の色フィルター１４，１５，１６（以下、「各色フィルター１４，１５，１６」と称する場合がある）及び隔壁１７の上面を平坦化するために設けられた層である。平坦化層１３は、例えばアクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂、フェノールノボラック系樹脂、ポリエステル系樹脂、ウレタン系樹脂、メラミン系樹脂、尿素系樹脂、スチレン系樹脂及びケイ素系樹脂等の樹脂を一又は複数含んだ樹脂により形成される。なお、平坦化層１３は、マイクロレンズ１８と一体化していても問題ない。平坦化層１３の膜厚は、例えば１［ｎｍ］以上３００［ｎｍ］以下である。混色防止の観点からは薄いほど好ましい。 (Planarization layer)
The flattening layer 13 is used to flatten the top surfaces of the first to third color filters 14, 15, 16 (hereinafter sometimes referred to as " color filters 14, 15, 16") and the partition walls 17. It is a layer provided. The flattening layer 13 is, for example, a resin such as an acrylic resin, an epoxy resin, a polyimide resin, a phenol novolac resin, a polyester resin, a urethane resin, a melamine resin, a urea resin, a urea resin, a styrene resin, and a silicon resin. It is formed of a resin containing one or more. There is no problem even if the flattening layer 13 is integrated with the microlens 18. The film thickness of the planarization layer 13 is, for example, not less than 1 nm and not more than 300 nm. From the viewpoint of preventing color mixing, the thinner the better.
（色フィルター）
　所定パターンで色フィルター層１００を構成する各色フィルター１４，１５，１６は、入射光を色分解する各色に対応するフィルターである。各色フィルター１４，１５，１６は、半導体基板１０とマイクロレンズ１８との間に設けられ、画素位置に応じて、複数の光電変換素子１１のそれぞれに対応するように予め設定された規則パターンで配置されている。 (Color filter)
The color filters 14, 15, 16 that constitute the color filter layer 100 in a predetermined pattern are filters that correspond to the respective colors that separate incident light. The color filters 14, 15, 16 are provided between the semiconductor substrate 10 and the micro lens 18, and are arranged in a regular pattern set in advance to correspond to each of the plurality of photoelectric conversion elements 11 according to the pixel position. It is done.
　図２に、各色フィルター１４，１５，１６及び各色フィルター１４，１５，１６の間に形成する隔壁１７の配列を平面的に示す。図２に示す配列は、いわゆるベイヤー配列であり、四隅が丸みをおびた四角形状の各色フィルター１４，１５，１６のパターン（第１、第２及び第３の色の色フィルタ）を敷き詰めた配列である。 FIG. 2 is a plan view showing the arrangement of the color filters 14, 15, 16 and the partitions 17 formed between the color filters 14, 15, 16. The arrangement shown in FIG. 2 is a so-called Bayer arrangement, and is an arrangement in which patterns of quadrangular color filters 14, 15 and 16 (first, second and third color filters) are rounded with four corners rounded. It is.
　各色フィルター１４，１５，１６は、所定の色の顔料（着色剤）と、熱硬化成分や光硬化成分を含んでいる。例えば、第１の色の色フィルター１４は着色剤としてグリーン顔料を含み、第２色の色フィルター１５はブルー顔料を含み、第３の色の色フィルター１６はレッド顔料を含んでいる。 Each color filter 14, 15, 16 contains a pigment (colorant) of a predetermined color, and a thermosetting component or a light curing component. For example, the first color filter 14 includes a green pigment as a colorant, the second color filter 15 includes a blue pigment, and the third color filter 16 includes a red pigment.
　本実施形態では、第１の色の色フィルター１４は、熱硬化性樹脂と光硬化性樹脂とを含んでいるが、熱硬化性樹脂の配合量の方が多いことが好ましい。この場合、例えば、固形分中の硬化成分は５質量％以上４０質量％以下とし、熱硬化性樹脂を５質量％以上２０質量％以下とし、光硬化性樹脂を１質量％以上２０質量％以下、好ましくは熱硬化性樹脂を５質量％以上１５質量％以下とし、光硬化性樹脂を１質量％以上１０質量％以下の範囲とする。
　ここで、硬化成分を熱硬化成分のみとする場合には、固形分中の硬化成分は５質量％以上４０質量％以下、より好ましくは５質量％以上１５質量％以下の範囲とする。
一方、硬化成分を光硬化成分のみとする場合には、固形分中の硬化成分は１０質量％以上４０質量％以下、より好ましくは１０質量％以上２０質量％以下の範囲とする。 In the present embodiment, the color filter 14 of the first color contains a thermosetting resin and a photocurable resin, but it is preferable that the blending amount of the thermosetting resin is larger. In this case, for example, the curing component in the solid content is 5% by mass to 40% by mass, the thermosetting resin is 5% by mass to 20% by mass, and the photocurable resin is 1% by mass to 20% by mass Preferably, the thermosetting resin is 5% by mass to 15% by mass, and the photocurable resin is in the range of 1% by mass to 10% by mass.
Here, when the curing component is only the thermosetting component, the curing component in the solid content is in the range of 5% by mass to 40% by mass, more preferably 5% by mass to 15% by mass.
On the other hand, when the curing component is only the photocuring component, the curing component in the solid content is in the range of 10% by mass to 40% by mass, more preferably 10% by mass to 20% by mass.
（隔壁）
　隔壁１７は、複数色の色フィルター１４、１５、１６のそれぞれの間に構成される。本実施形態では、第１の色の色フィルター１４の側壁部に設けられた隔壁１７により、第１の色の色フィルター１４と第２、第３の色の色フィルター１５、１６のそれぞれを分けることができる。隔壁１７は、第１の色の色フィルター１４に含まれる第１の色の色フィルター用材料及び透明導電層１２に含まれる材料と、第１の色の色フィルター１４を形成する際に用いるドライエッチングガスとの反応生成物を含んでいる。 (Partition wall)
The partition wall 17 is formed between each of the color filters 14, 15, 16 of a plurality of colors. In the present embodiment, the partition wall 17 provided on the side wall portion of the first color filter 14 separates the first color color filter 14 and the second and third color filters 15 and 16. be able to. The partition wall 17 is a material for the color filter for the first color contained in the color filter 14 for the first color, a material contained in the transparent conductive layer 12, and a dry used for forming the color filter 14 for the first color It contains the reaction product with the etching gas.
　隔壁１７の材料は、第１の色の色フィルター１４に含まれる材料及び透明導電層１２の材料を含有している。隔壁１７の材料は、たとえば亜鉛、銅、ニッケル、珪素、炭素、酸素、水素、窒素、臭素、塩素から少なくとも一種を含んだ化合物を含んでおり、透明導電層１２に使用される材料として珪素、炭素、酸素、水素、錫、亜鉛、インジウム、アルミニウム、ガリウム、チタン、モリブデン、タングステン、カドミウム、ニオブ、タンタル、ハフニウム、銀、フッ素から少なくとも一種を含んだ化合物から形成される。透明導電層１２にＩＴＯを用いた場合は、インジウム、錫、酸素などを含んだ材料が隔壁１７に微量含まれることがある。透明導電層１２にＩＴＯなどを用いる場合は、エッチング条件によりエッチング量が微量となるため、隔壁１７の材料は第１の色の色フィルター材料が大半の割合を占める。 The material of the partition 17 contains the material contained in the color filter 14 of the first color and the material of the transparent conductive layer 12. The material of the partition 17 includes, for example, a compound containing at least one of zinc, copper, nickel, silicon, carbon, oxygen, hydrogen, nitrogen, bromine and chlorine, and silicon as a material used for the transparent conductive layer 12 It is formed of a compound containing at least one of carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine. When ITO is used for the transparent conductive layer 12, a material containing indium, tin, oxygen or the like may be contained in a small amount in the partition wall 17. When ITO or the like is used for the transparent conductive layer 12, the amount of etching becomes very small depending on the etching conditions, so the material of the partition wall 17 is mostly occupied by the color filter material of the first color.
　本実施形態では、図２に示すベイヤー配列の各色フィルター１４，１５，１６を有する固体撮像素子１について説明する。しかしながら、固体撮像素子１の色フィルターは、必ずしもベイヤー配列に限定されず、また、色フィルターの色もレッド（Ｒ）、グリーン（Ｇ）、ブルー（Ｂ）の３色に限定されない。また、色フィルターの配列の一部に屈折率を調整した透明の層を配置してもよい。 In this embodiment, a solid-state imaging device 1 having the color filters 14, 15, 16 of the Bayer arrangement shown in FIG. 2 will be described. However, the color filters of the solid-state imaging device 1 are not necessarily limited to the Bayer arrangement, and the colors of the color filters are not limited to three colors of red (R), green (G), and blue (B). In addition, a transparent layer whose refractive index is adjusted may be disposed in part of the arrangement of color filters.
　　第１の色の色フィルター１４の膜厚Ａ［ｎｍ］は、２００［ｎｍ］以上７００［ｎｍ］以下に形成する。好ましくは、膜厚Ａ［ｎｍ］は、４００［ｎｍ］以上６００［ｎｍ］以下である。より好ましくは膜厚Ａ［ｎｍ］は５００［ｎｍ］以下である。 The film thickness A [nm] of the color filter 14 of the first color is formed to be 200 [nm] or more and 700 [nm] or less. Preferably, the film thickness A [nm] is 400 [nm] or more and 600 [nm] or less. More preferably, the film thickness A [nm] is 500 [nm] or less.
　また透明導電層１２の膜厚Ｂ［ｎｍ］は、前述した値である０［ｎｍ］より大きく２００［ｎｍ］以下に形成する。好ましくは、膜厚Ｂ［ｎｍ］は、５［ｎｍ］以上８０［ｎｍ］以下である。より好ましくは膜厚Ｂ［ｎｍ］は５０［ｎｍ］以下である。 The film thickness B [nm] of the transparent conductive layer 12 is larger than 0 [nm], which is the value described above, and is 200 [nm] or less. Preferably, the film thickness B [nm] is 5 [nm] or more and 80 [nm] or less. More preferably, the film thickness B [nm] is 50 [nm] or less.
　また、第１の色以外の色の色フィルター１５，１６の膜厚をＣ［ｎｍ］とした場合に、下記式を満足する膜厚に形成する。
　Ａ＋Ｂ－２００［ｎｍ］≦Ｃ≦Ａ＋Ｂ＋２００［ｎｍ］
　但し、第２の色の色フィルター１５の膜厚と、第３の色の色フィルター１６の膜厚とが異なっていても良い。ここで、（Ａ＋Ｂ）の膜厚とＣの膜厚との膜厚差を２００［ｎｍ］以下としているのは、一部の膜厚差が２００［ｎｍ］を越える部分があると、他の画素への斜め入射光の影響により、受光感度が低下するおそれがあるためである。また、色フィルター層１００に２００［ｎｍ］を越える段差が形成される場合、上部のマイクロレンズ１８の形成が困難となる場合がある。 When the film thickness of the color filters 15 and 16 of colors other than the first color is C [nm], the film thickness is formed to satisfy the following equation.
A + B-200 [nm] ≦ C ≦ A + B + 200 [nm]
However, the film thickness of the color filter 15 of the second color may be different from the film thickness of the color filter 16 of the third color. Here, the reason why the film thickness difference between the film thickness of (A + B) and the film thickness of C is 200 nm or less is that there is a portion where the film thickness difference is more than 200 nm. This is because the light receiving sensitivity may be reduced due to the influence of the oblique incident light on the pixel. In addition, in the case where a level difference exceeding 200 [nm] is formed in the color filter layer 100, the formation of the upper microlens 18 may be difficult.
　また、色フィルター層１００を薄膜化するため、第１から第３の色の色フィルター１４，１５，１６に含有する顔料（着色剤）の濃度は、５０質量％以上であることが好ましい。 In order to thin the color filter layer 100, the concentration of the pigment (colorant) contained in the first to third color filters 14, 15, 16 is preferably 50% by mass or more.
　ままた、隔壁１７が複数色の色フィルター１４、１５、１６のそれぞれの間に形成されている。隔壁は、幅(寸法)が２００ｎｍ以下で形成されている。ここで、隔壁の高さを２００ｎｍ以下としているのは、隔壁の幅(寸法)が２００ｎｍより大きくなると、隔壁によって光電変換素子１１に入射する光が大幅に低減されて受光感度が低減してしまうおそれがあるためである。 As it is, the partition wall 17 is formed between each of the color filters 14, 15, 16 of a plurality of colors. The partition wall is formed to have a width (dimension) of 200 nm or less. Here, the reason why the height of the partition is 200 nm or less is that when the width (dimension) of the partition is larger than 200 nm, the light incident on the photoelectric conversion element 11 is significantly reduced by the partition and the light receiving sensitivity is reduced. It is because there is a fear.
　＜固体撮像素子の製造方法＞
　次に、図３及び図４を参照して、第１の実施形態の固体撮像素子の製造方法について説明する。 <Method of manufacturing solid-state imaging device>
Next, with reference to FIGS. 3 and 4, a method of manufacturing the solid-state imaging device according to the first embodiment will be described.
　（透明導電層の形成工程）
　図３（ａ）に示すように、複数の光電変換素子１１を有する半導体基板１０を準備し、その表面の色フィルター層形成位置全面に、透明導電層１２を形成する。透明導電層１２は、例えば上述した珪素、炭素、酸素、水素、錫、亜鉛、インジウム、アルミニウム、ガリウム、チタン、モリブデン、タングステン、カドミウム、ニオブ、タンタル、ハフニウム、銀、フッ素等の材料を一つもしくは複数含んだ化合物や、酸化化合物、窒化化合物等により形成される。 (Step of forming transparent conductive layer)
As shown to Fig.3 (a), the semiconductor substrate 10 which has the several photoelectric conversion element 11 is prepared, and the transparent conductive layer 12 is formed in the color filter layer formation position whole surface of the surface. The transparent conductive layer 12 is made of, for example, one of the aforementioned materials such as silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, fluorine and the like Alternatively, it is formed of a compound containing a plurality of compounds, an oxide compound, a nitride compound, or the like.
　透明導電層１２として上述した化合物の膜を、スプレー法、塗布法、ＣＶＤ法などの化学的作製法と真空蒸着法、イオンプレーティング法、スパッタ法などの物理的作製方法で形成する。化学的作製方法は、塩化物の加水分解や、有機化合物の熱分解反応により作製する方法である。また、透明導電層１２はこれらの材料を含んだ物質の塗布、加熱硬化などで形成しても良い。 A film of the above-described compound is formed as the transparent conductive layer 12 by a chemical preparation method such as a spray method, an application method, a CVD method and a physical preparation method such as a vacuum evaporation method, an ion plating method, or a sputtering method. The chemical preparation method is a method of preparing by hydrolysis of chloride or thermal decomposition reaction of an organic compound. In addition, the transparent conductive layer 12 may be formed by coating a material containing these materials, heat curing, or the like.
　この際、半導体基板１０の全面に透明導電層１２を形成した場合、半導体基板１０の電極部分なども覆っているため、電極部分の透明導電層１２を除去する必要がある。透明導電層１２の部分的な除去方法としては、マスク材料で除去部分だけを開口させてドライエッチングやウェットエッチングなどの除去方法を用いることや、リフトオフ法などの事前に除去可能な材料で埋めておく方法などの公知の方法が使用できる。透明導電層１２にＩＴＯを用いる場合は、非加熱形成で非晶質のＩＴＯを形成し、フォトレジストを用いてマスク構造を形成し、しゅう酸などでウェットエッチングを行い、電極部分を開口させて、その後半導体基板を加熱することで、ＩＴＯを結晶化させても良い。 At this time, when the transparent conductive layer 12 is formed on the entire surface of the semiconductor substrate 10, since the electrode portion and the like of the semiconductor substrate 10 are also covered, it is necessary to remove the transparent conductive layer 12 of the electrode portion. As a method of partially removing the transparent conductive layer 12, only the removed portion is opened with a mask material and a removal method such as dry etching or wet etching is used, or filling with a material that can be removed beforehand such as liftoff method Known methods such as storage methods can be used. When ITO is used for the transparent conductive layer 12, amorphous ITO is formed by non-heating formation, a mask structure is formed using a photoresist, wet etching is performed with oxalic acid, and the electrode portion is opened. Then, the ITO may be crystallized by heating the semiconductor substrate.
　ここで、本実施形態に係る固体撮像素子の製造方法は、従来の感光性色フィルター用材料を用いてフォトリソグラフィによって色フィルター層１００を構成する各色フィルター１４，１５，１６を直接パターニングして製造する方法とは異なる。すなわち、本実施形態に係る固体撮像素子１の製造方法では、第１の色の色フィルター用材料を全面に塗布し硬化させて第１の色の色フィルター層１４ａを形成した後で（図３（ｄ）参照）、その第１の色の色フィルター層１４ａにおける他の色フィルターを形成する箇所をドライエッチングで除去する。これにより、第１の色の色フィルター１４のパターン（図４（ｃ）参照）が形成される。また、第１の色の色フィルター層１４ａ及び透明導電層１２の一部をドライエッチングする際に生じる、第１の色の色フィルター層１４ａ及び透明導電層１２とドライエッチングガスの反応生成物が第１の色の色フィルター１４の側壁（すなわち外周囲）に隔壁１７として形成される。そして、周辺が第１の色の色フィルター１４及び隔壁１７で囲まれている部分に第２以降の色フィルター（第２及び第３の色の色フィルターのパターン１５，１６）をパターン形成する。このとき、先に形成した第１の色の色フィルター１４及び隔壁１７のパターンをガイドパターンとして用いて、高温の加熱処理により第２以降の色フィルター材料を硬化させる。このため、半導体基板１０と色フィルター１５，１６との密着性を向上させることができる。
　以下、その形成工程について説明する。 Here, the manufacturing method of the solid-state imaging device according to the present embodiment is manufactured by directly patterning the color filters 14, 15, 16 constituting the color filter layer 100 by photolithography using a conventional photosensitive color filter material. It is different from the way you do it. That is, in the method of manufacturing the solid-state imaging device 1 according to the present embodiment, the first color filter material is applied to the entire surface and cured to form the first color filter layer 14a (FIG. 3) (See (d)) The portions of the first color filter layer 14a where the other color filters are to be formed are removed by dry etching. Thereby, a pattern of the color filter 14 of the first color (see FIG. 4C) is formed. In addition, the reaction product of the first color filter layer 14 a and the transparent conductive layer 12 with the dry etching gas, which is generated when the first color filter layer 14 a and the transparent conductive layer 12 are partially dry etched, is used. A partition 17 is formed on the side wall (i.e., the outer periphery) of the color filter 14 of the first color. Then, second and subsequent color filters ( patterns 15 and 16 of the second and third color filters) are formed in a pattern surrounded by the first color filter 14 and the partition wall 17. At this time, the second and subsequent color filter materials are cured by high-temperature heat treatment using the pattern of the color filters 14 and partitions 17 of the first color formed previously as a guide pattern. Therefore, the adhesion between the semiconductor substrate 10 and the color filters 15 and 16 can be improved.
Hereinafter, the formation process will be described.
（第１の色の色フィルター層形成工程（第１の工程））
　まず、半導体基板１０上に形成した透明導電層１２の表面に、第１の色の色フィルター１４を形成する工程について図３から図５を用いて説明する。第１の色の色フィルター１４は、固体撮像素子で最も専有面積の広い色の色フィルターが好ましい。 (Step of forming first color filter layer (first step))
First, the process of forming the color filter 14 of the first color on the surface of the transparent conductive layer 12 formed on the semiconductor substrate 10 will be described with reference to FIGS. 3 to 5. The color filter 14 of the first color is preferably a solid-state imaging device and a color filter with the widest occupied area.
　第１の色の色フィルター層形成工程では、複数の光電変換素子１１を二次元的に配置した半導体基板１０に透明導電層１２を形成し、透明導電層１２上に第１の色の色フィルター１４用の塗布液を塗布し硬化させて透明導電層１２及び第１の色の色フィルター層１４ａをこの順に形成した後、第１の色の色フィルター１４の配置位置以外の第１の色の色フィルター層１４ａ部分をドライエッチングによって除去して第１の色の色フィルター１４をパターン形成する。以下、第１の色の色フィルター層形成工程の詳細について説明する。 In the color filter layer forming step of the first color, the transparent conductive layer 12 is formed on the semiconductor substrate 10 in which the plurality of photoelectric conversion elements 11 are two-dimensionally arranged, and the color filter of the first color is formed on the transparent conductive layer 12 The coating solution for 14 is applied and cured to form the transparent conductive layer 12 and the color filter layer 14a of the first color in this order, and then the first color of the first color other than the arrangement position of the color filter 14 A portion of the color filter layer 14a is removed by dry etching to pattern the color filter 14 of the first color. Hereinafter, the details of the color filter layer forming step of the first color will be described.
　複数の光電変換素子１１が二次元的に配置された半導体基板１０上に透明導電層１２を形成する。次に、半導体基板１０上に形成した透明導電層１２上、すなわち透明導電層１２の表面（図３（ａ）参照）に、図３（ｂ）に示すように、樹脂材料を主成分とし第１の顔料（着色剤）を分散させた第１の樹脂分散液からなる第１の色の色フィルター用材料を塗布し、第１の色の色フィルター層１４ａを形成する。本実施形態に係る固体撮像素子１は、図２に示すようにベイヤー配列の色フィルターを用いることを想定している。このため、第１の色は、緑（Ｇ）であることが好ましい。第１の色の色フィルター層１４ａは、最終的に形成される第１の色の色フィルター１４と同じか僅かに厚い膜厚を有するが、図３及び後述する図４では説明の便宜上、第１の色の色フィルター１４（図５参照）よりも膜厚が薄い状態で図示されている。 A transparent conductive layer 12 is formed on a semiconductor substrate 10 in which a plurality of photoelectric conversion elements 11 are two-dimensionally arranged. Next, on the transparent conductive layer 12 formed on the semiconductor substrate 10, that is, on the surface of the transparent conductive layer 12 (see FIG. 3A), as shown in FIG. A first color color filter material composed of a first resin dispersion liquid in which a first pigment (colorant) is dispersed is applied to form a first color color filter layer 14a. The solid-state imaging device 1 according to the present embodiment is assumed to use a Bayer-arranged color filter as shown in FIG. For this reason, the first color is preferably green (G). The color filter layer 14a of the first color has the same or slightly thicker film thickness as the color filter 14 of the first color to be finally formed, but in FIG. 3 and FIG. The film thickness is shown to be thinner than the color filter 14 of one color (see FIG. 5).
　第１の色の色フィルター用材料の樹脂材料としては、エポキシ樹脂等の熱硬化性樹脂及び紫外線硬化樹脂等の光硬化性樹脂を含有する混合樹脂を用いる。但し、光硬化性樹脂の配合量を熱硬化性樹脂の配合量よりも少なくする。樹脂材料として熱硬化性樹脂を多く用いることで、硬化性樹脂として光硬化性樹脂を多く用いる場合と異なり、第１の色の色フィルター層１４ａの顔料含有率を高くすることが可能となり、薄膜で且つ所望の分光特性を得られる第１の色の色フィルター１４を形成し易くなる。ただし、本実施形態では、熱硬化性樹脂及び光硬化性樹脂の両方を含有する混合樹脂で説明するが、必ずしも混合樹脂に限定されず、いずれか一方の硬化性樹脂のみを含有する樹脂でもよい。 As a resin material of the color filter material of the first color, a mixed resin containing a thermosetting resin such as an epoxy resin and a photocurable resin such as an ultraviolet curable resin is used. However, the compounding amount of the photocurable resin is made smaller than the compounding amount of the thermosetting resin. By using a large amount of thermosetting resin as the resin material, it is possible to increase the pigment content of the color filter layer 14a of the first color, unlike the case of using a large amount of photocurable resin as the curable resin. In addition, it is easy to form the color filter 14 of the first color that can obtain desired spectral characteristics. However, in the present embodiment, although a mixed resin containing both a thermosetting resin and a photocurable resin is described, it is not necessarily limited to the mixed resin, and a resin containing only one of the curable resins may be used. .
　次に、図３（ｃ）に示すように、第１の色の色フィルター層１４ａの全面に紫外線を照射して、第１の色の色フィルター層１４ａを光硬化する。本実施形態では、従来手法のように色フィルター用材料に感光性を持たせて露光することで所望のパターンを直接形成する場合と異なり、第１の色の色フィルター層１４ａの全面を硬化するため、感光性成分の含有量を低下させても硬化が可能となる。第１の色の色フィルター用材料に光硬化性樹脂を混合しない場合は、この露光工程を実施しなくても良い。後述する溶剤耐性などが、光硬化性樹脂を含有しなくても満足できる場合は、光硬化性樹脂を除去することで、より顔料濃度を向上させ、薄膜化が可能となる。 Next, as shown in FIG. 3C, the entire surface of the color filter layer 14a of the first color is irradiated with ultraviolet light to photocure the color filter layer 14a of the first color. In the present embodiment, unlike the case where a desired pattern is directly formed by exposing the color filter material to photosensitivity and exposing it as in the conventional method, the entire surface of the color filter layer 14a of the first color is cured. Therefore, curing is possible even if the content of the photosensitive component is reduced. When the photocurable resin is not mixed with the color filter material of the first color, this exposure step may not be performed. If the solvent resistance described later can be satisfied without containing the photocurable resin, the pigment concentration can be further improved and the film can be thinned by removing the photocurable resin.
　次に、図３（ｄ）に示すように、第１の色の色フィルター層１４ａを１５０℃以上３００℃以下で熱硬化する。より具体的には、第１の色の色フィルター層１４ａの硬化時の加熱温度は、１７０℃以上２７０℃以下であることが好ましい。固体撮像素子の製造においては、マイクロレンズ１８の形成時に１００℃以上３００℃以下の高温加熱工程が用いられることが多いため、第１の色の色フィルター用材料は、高温耐性があることが望ましい。このため、樹脂材料として、高温耐性のある熱硬化性樹脂を用いることがより好ましい。 Next, as shown in FIG. 3D, the color filter layer 14a of the first color is thermally cured at 150 ° C. or more and 300 ° C. or less. More specifically, the heating temperature at the time of curing of the color filter layer 14a of the first color is preferably 170 ° C. or more and 270 ° C. or less. In the manufacture of solid-state imaging devices, it is desirable that the color filter material of the first color have high temperature resistance because a high temperature heating step of 100 ° C. or more and 300 ° C. or less is often used when forming the microlenses 18 . Therefore, it is more preferable to use a thermosetting resin having high temperature resistance as the resin material.
　次に、図４（ａ）から図４（ｃ）に示すように、前工程で形成した第１の色の色フィルター層１４ａ上に開口部を有するエッチングマスクパターンを形成する。
　まず、図４（ａ）に示すように、第１の色の色フィルター層１４ａの表面に、感光性樹脂材料を塗布して乾燥し、エッチングマスク２０を形成する。
　次に、図４（ｂ）に示すように、感光性樹脂層に対してフォトマスク（図示せず）を用いて第１の色の色フィルター１４を形成しない位置に相当する第１の色の色フィルター層１４ａの領域を露光し、必要なパターン以外が現像液に可溶となる化学反応を起こす。 Next, as shown in FIG. 4A to FIG. 4C, an etching mask pattern having an opening is formed on the first color filter layer 14a formed in the previous step.
First, as shown in FIG. 4A, a photosensitive resin material is applied to the surface of the color filter layer 14a of the first color and dried to form an etching mask 20.
Next, as shown in FIG. 4B, the first color corresponding to the position where the color filter 14 of the first color is not formed using a photomask (not shown) for the photosensitive resin layer The area of the color filter layer 14a is exposed to cause a chemical reaction which makes the developer soluble in areas other than the required pattern.
　次に、図４（ｃ）に示すように、現像によりエッチングマスク２０の不要部（露光部）を除去する。これにより、開口部２０ｂを有するエッチングマスクパターン２０ａが形成される。開口部２０ｂの位置には、後の工程で第２の色の色フィルター又は第３の色の色フィルターが形成される。 Next, as shown in FIG. 4C, the unnecessary portion (exposed portion) of the etching mask 20 is removed by development. Thus, the etching mask pattern 20a having the opening 20b is formed. At the position of the opening 20b, a color filter of the second color or a color filter of the third color is formed in a later step.
　感光性樹脂材料としては、例えば、アクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂、フェノールノボラック系樹脂、その他の感光性を有する樹脂を単独で又は複数混合あるいは共重合して用いることができる。感光性樹脂層をパターニングするフォトリソグラフィプロセスに用いる露光機は、スキャナー、ステッパー、アライナー、ミラープロジェクションアライナーが挙げられる。また、電子線での直接描画、レーザでの描画等により露光を行ってもよい。なかでも、微細化の必要な固体撮像素子の第１の色の色フィルター１４を形成するためには、ステッパーやスキャナーが一般的に用いられる。 As the photosensitive resin material, for example, an acrylic resin, an epoxy resin, a polyimide resin, a phenol novolac resin, and other photosensitive resins may be used alone or in combination or copolymerized. The exposure machine used for the photolithography process which patterns the photosensitive resin layer includes a scanner, a stepper, an aligner, and a mirror projection aligner. Further, exposure may be performed by direct drawing with an electron beam, drawing with a laser, or the like. Above all, a stepper or a scanner is generally used to form the first color color filter 14 of the solid-state imaging device which needs to be miniaturized.
　感光性樹脂材料としては、高解像で高精度なパターンを作製するために、一般的なフォトレジストを用いることが望ましい。フォトレジストを用いることで、感光性を持たせた色フィルター用材料でパターンを形成する場合と異なり、形状制御が容易で、寸法精度の良いパターンを形成することが出来る。 As a photosensitive resin material, it is desirable to use a general photoresist in order to produce a pattern with high resolution and high accuracy. By using a photoresist, unlike the case of forming a pattern with a photosensitive color filter material, shape control is easy and a pattern with high dimensional accuracy can be formed.
　この際用いるフォトレジストは、ドライエッチング耐性の高いものが望ましい。ドライエッチング時のエッチングマスク材として用いる場合は、エッチング部材とのエッチング速度である選択比を向上させるために、現像後にポストベークと呼ばれる熱硬化工程が用いられることが多い。しかし、熱硬化工程が含まれると、ドライエッチング後に、エッチングマスクとして用いた残留レジストの除去工程での除去が困難となることがある。このため、フォトレジストとしては、熱硬化工程を用いなくてもエッチング部材との間で選択比が得られるものが好ましい。また、良好な選択比が得られない場合、フォトレジスト材料の膜厚を厚く形成する必要があるが、厚膜化すると微細パターン形成が困難となる。このため、フォトレジストとしては、ドライエッチング耐性が高い材料が好ましい。 The photoresist used at this time preferably has high dry etching resistance. When using as an etching mask material at the time of dry etching, in order to improve the selectivity which is an etching rate with an etching member, a thermosetting process called post-baking is often used after development. However, if the heat curing step is included, it may be difficult to remove the remaining resist used as the etching mask in the removal step after dry etching. For this reason, as the photoresist, one which can obtain a selection ratio with the etching member without using the thermosetting process is preferable. In addition, when a good selectivity can not be obtained, the film thickness of the photoresist material needs to be formed thick, but when the film thickness is increased, it becomes difficult to form a fine pattern. Therefore, as the photoresist, a material having high dry etching resistance is preferable.
　具体的には、エッチングマスクである感光性樹脂材料とドライエッチングの対象である第１の色の色フィルター用材料のエッチング速度比（選択比）は、０．５以上が好ましく、０．８以上がより好ましい。この選択比があれば、エッチングマスクパターン２０ａを全て消滅させることなく、色フィルター１４をエッチングする事が可能である。第１の色の色フィルター用材料の膜厚が０．２μｍ以上０．７μｍ以下程度の場合、感光性樹脂層の膜厚は、０．５μｍ以上２．０μｍ以下程度であることが望ましい。 Specifically, the etching rate ratio (selectivity ratio) of the photosensitive resin material which is an etching mask and the color filter material of the first color which is a target of dry etching is preferably 0.5 or more, and 0.8 or more. Is more preferred. With this selection ratio, it is possible to etch the color filter 14 without eliminating the etching mask pattern 20a altogether. When the film thickness of the color filter material of the first color is about 0.2 μm or more and 0.7 μm or less, the film thickness of the photosensitive resin layer is desirably about 0.5 μm or more and 2.0 μm or less.
　また、この際に用いるフォトレジストとしては、ポジ型レジスト又は、ネガ型レジストのどちらでも問題ない。しかしながら、エッチング後のフォトレジスト除去を考えると、外部要因により、化学反応が進み硬化する方向に変化するネガ型レジストよりも、化学反応が進み溶解する方向に化学反応が起こりやすいポジ型レジストが望ましい。
　以上のようにして、エッチングマスクパターンが形成される。 Moreover, as a photoresist used at this time, either a positive resist or a negative resist may be used without any problem. However, considering photoresist removal after etching, it is desirable to use a positive resist that tends to undergo a chemical reaction and dissolve in a direction in which the chemical reaction proceeds and dissolves, rather than a negative resist in which the chemical reaction proceeds and hardens due to external factors. .
As described above, the etching mask pattern is formed.
　エッチングマスクパターン及びドライエッチングガスを用いたドライエッチングにより、図５（ａ）に示すように、開口部２０ｂから露出する第１の色の色フィルター層１４ａの一部分を除去する。
　ドライエッチングの手法としては、例えば、ＥＣＲ、平行平板マグネトロン、ＤＲＭ、ＩＣＰ、あるいは２周波タイプのＲＩＥ（Ｒｅａｃｔｉｖｅ　Ｉｏｎ　Ｅｔｃｈｉｎｇ）等が挙げられる。エッチング方式については特に制限されないが、幅数ｍｍ以上の大面積パターンや数百ｎｍの微小パターン等の線幅や面積が異なってもエッチングレートや、エッチング形状が変わらないように制御できる方式のものが望ましい。また１００ｍｍから４５０ｍｍ程度のサイズのウエハ全面で、面内均一にドライエッチングできる制御機構のドライエッチング手法を用いることが望ましい。 By dry etching using an etching mask pattern and a dry etching gas, as shown in FIG. 5A, a part of the color filter layer 14a of the first color exposed from the opening 20b is removed.
As a method of dry etching, for example, ECR, parallel plate magnetron, DRM, ICP, or dual frequency type RIE (Reactive Ion Etching) may be mentioned. Although the etching method is not particularly limited, it is a method that can control so that the etching rate and the etching shape do not change even if the line width or area of a large area pattern of several mm or more or a minute pattern of several hundreds of nm is different. Is desirable. In addition, it is desirable to use a dry etching method of a control mechanism capable of performing in-plane dry etching uniformly on the entire surface of a wafer having a size of about 100 mm to 450 mm.
　ドライエッチングガスは、反応性（酸化性・還元性）を有する、すなわちエッチング性のあるガスであればよい。反応性を有するガスとしては、例えば、フッ素、酸素、臭素、硫黄及び塩素等を含むガスを挙げることができる。また、アルゴンやヘリウム等の反応性が少なくイオンでの物理的衝撃によるエッチングを行う元素を含む希ガスを単体又は混合させて使用することが出来る。その為、ドライエッチングに用いるガスは、フッ素、酸素、水素、硫黄、炭素、臭素、塩素、窒素、アルゴン、ヘリウム、キセノン、クリプトンから選ばれる少なくとも１種類を含有するガスである。フッ素を含有したガスとしては、たとえば、ＣＦ４、Ｃ２Ｆ６、Ｃ３Ｆ８、Ｃ３Ｆ６、Ｃ４Ｆ８、Ｃ４Ｆ１０、ＣＨＦ３、ＣＣｌＦ３、ＣＣｌ３Ｆ、ＮＦ３、ＳＦ６、ＨＦなどであり、これらのフッ素系ガスを複数混合させたドライエッチングガスを用いても良い。 The dry etching gas may be a reactive (oxidative / reductive) gas, that is, an etchable gas. Examples of the reactive gas include gases containing fluorine, oxygen, bromine, sulfur, chlorine and the like. Further, a rare gas such as argon or helium which is less reactive and contains an element to be etched by physical impact with ions can be used alone or in combination. Therefore, the gas used for dry etching is a gas containing at least one selected from fluorine, oxygen, hydrogen, sulfur, carbon, bromine, chlorine, nitrogen, argon, helium, xenon and krypton. As the gas containing fluorine, for example, CF 4 , C 2 F 6 , C 3 F 8 , C 3 F 6 , C 4 F 8 , C 4 F 10 , CHF 3 , CClF 3 , CCl 3 F, NF 3 Alternatively, a dry etching gas in which a plurality of these fluorine-based gases are mixed may be used, such as SF 6 or HF.
　またガスを用いてのプラズマ環境下でのドライエッチング工程で、所望のパターンを形成する反応を起こすガスであれば、これらには限定されなくても問題ない。本実施形態では初期の段階で全ガス流量の９０％以上を希ガス等のイオンの物理的衝撃が主体でエッチングを行うガスとし、そこにフッ素系ガスや酸素系ガスを混合したエッチングガスを用いることで、化学反応も利用してエッチングレートを向上させる。 Moreover, if it is a gas that causes a reaction to form a desired pattern in a dry etching process under a plasma environment using a gas, there is no problem even if it is not limited to these. In the present embodiment, 90% or more of the total gas flow rate in the initial stage is a gas that performs etching mainly by physical impact of ions such as a rare gas, and uses an etching gas in which a fluorine-based gas or an oxygen-based gas is mixed therein. Thus, the chemical reaction is also used to improve the etching rate.
　ドライエッチングガスに希ガスを多く用いることで、希ガスイオンの物理的衝撃による効果により、垂直にエッチングが進行する異方性エッチングが進行しやすい条件となる。そのため、色フィルターのエッチングの初期では、希ガスが多い条件でエッチングを実施する。 By using a large amount of the rare gas as the dry etching gas, anisotropic etching in which the etching progresses vertically is likely to progress because of the effect of physical impact of the rare gas ions. Therefore, in the initial stage of the etching of the color filter, the etching is performed under the condition of a large amount of rare gas.
　固体撮像素子の半導体基板１０はシリコンを主体とした材料により構成されている。このため、フッ素を含有したガスなど反応性の高いガスを用いてドライエッチングを行うと、半導体基板１０がエッチングされてしまう可能性がある。その為、ドライエッチングを行う際、半導体基板１０をエッチングしないガスを用いることが好ましい。また、半導体基板１０をエッチングするガスを用いる場合には、最初に半導体基板１０をエッチングするガスを用い、途中で半導体基板１０をエッチングし難いガスに変更してエッチングを行う多段階エッチングとしてもよい。なお、半導体基板１０に影響がなく、エッチングマスクパターン２０ａを用いて垂直に近い形状で第１の色の色フィルター用材料のエッチングが可能であり、第１の色の色フィルター用材料の残渣が形成されなければ、エッチングガスの種類は制限されない。 The semiconductor substrate 10 of the solid-state imaging device is made of a material mainly made of silicon. Therefore, when dry etching is performed using a highly reactive gas such as a gas containing fluorine, the semiconductor substrate 10 may be etched. Therefore, when dry etching is performed, it is preferable to use a gas that does not etch the semiconductor substrate 10. In addition, in the case of using a gas for etching the semiconductor substrate 10, it is possible to use a gas for etching the semiconductor substrate 10 first and change the semiconductor substrate 10 to a gas that is difficult to etch halfway to perform etching in multiple steps. . The first color filter material can be etched in a shape close to vertical using the etching mask pattern 20a without affecting the semiconductor substrate 10, and residues of the first color color filter may be used. If not formed, the type of etching gas is not limited.
　しかし、本実施形態では透明導電層１２に珪素、炭素、酸素、水素、錫、亜鉛、インジウム、アルミニウム、ガリウム、チタン、モリブデン、タングステン、カドミウム、ニオブ、タンタル、ハフニウム、銀、フッ素等の材料を一つ又は複数含んだ化合物や、酸化化合物、窒化化合物等を用いる場合、フッ素を含有したガスに対して、ドライエッチング耐性があり、透明導電層１２のエッチング速度が遅いため、所望の位置の色フィルターを除去して、透明導電層１２でエッチングを止めて、下層の半導体基板１０をエッチングしないことが可能となる。 However, in the present embodiment, the transparent conductive layer 12 is made of a material such as silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, fluorine and the like. When a compound containing one or more, an oxide compound, a nitride compound, or the like is used, the color of the desired position is resistant to dry etching with respect to a gas containing fluorine and the etching rate of the transparent conductive layer 12 is slow. It is possible to remove the filter and stop the etching with the transparent conductive layer 12 so that the underlying semiconductor substrate 10 is not etched.
　具体的には、希ガスの単ガス又は反応性ガスと希ガスの混合ガスの全ガス流量の９０％以上が希ガスで、開口部２０ｂに露出する第１の色の色フィルター層１４ａ及び透明導電層１２の一部をエッチングする。この時、半導体基板１０へのダメージを低減するために、エッチングを途中で止めて、物理的にエッチングを行う希ガスの割合を低減してエッチングしても良い。 Specifically, at least 90% of the total gas flow of the single gas of the rare gas or the mixed gas of the reactive gas and the rare gas is the rare gas, and the color filter layer 14a of the first color exposed in the opening 20b and the transparent A portion of the conductive layer 12 is etched. At this time, in order to reduce the damage to the semiconductor substrate 10, the etching may be stopped midway to reduce the ratio of the rare gas to be physically etched.
　次の段階では、透明導電層１２をエッチングし難い、酸素、フッ素系ガスを用いて、開口部２０ｂに露出する第１の色の色フィルター層１４ａを全てエッチングする。この際用いる条件は、透明導電層１２のエッチング速度が遅いため、色フィルターを残渣なくエッチングし、透明導電層１２が無くならない時間で行う。図５では透明導電層１２がドライエッチングガスに耐性があり、ほぼエッチングが進んでいない構成を示している。 In the next step, all the color filter layers 14a of the first color exposed in the openings 20b are etched using oxygen and a fluorine-based gas which is difficult to etch the transparent conductive layer 12. Since the etching rate of the transparent conductive layer 12 is slow, the conditions used at this time are such that the color filter is etched without any residue and the transparent conductive layer 12 is not lost. FIG. 5 shows a configuration in which the transparent conductive layer 12 is resistant to the dry etching gas and the etching is hardly advanced.
　この際、透明導電層１２が完全に無くならない範囲であれば、ドライエッチングガスに希ガスを混ぜて、異方性を高めたエッチングを行っても良い。この条件の場合、希ガスの物理的衝撃により、透明導電層の材料が隔壁１７に含有しやすくなる。以上のようにして、図５（ａ）に示すように、第１の色の色フィルター１４が形成される。 At this time, as long as the transparent conductive layer 12 is not completely eliminated, a rare gas may be mixed with the dry etching gas to perform etching with enhanced anisotropy. Under this condition, the physical impact of the rare gas makes it easier for the material of the transparent conductive layer to be contained in the partition wall 17. As described above, as shown in FIG. 5A, the color filter 14 of the first color is formed.
（隔壁形成工程（第２の工程））
　また、第１の色の色フィルター１４をパターン形成する工程において、図５（ａ）に示すように、第１の色の色フィルター層１４ａ及び透明導電層１２をドライエッチングする際に生成される反応生成物（副生成物の一例）を、最終的に各色フィルター１４，１５，１６のそれぞれの間に設けられる隔壁１７を第１の色の色フィルター１４の側壁に形成する。隔壁１７は、第１の色の色フィルター用材料及び透明導電層材料とドライエッチングガスとの反応生成物により形成される。この際、異方性のあるエッチングを行う場合は、ドライエッチングによる反応生成物が第１の色の色フィルター１４の側壁へ付着して形成される側壁保護層の制御が重要となる。また、ドライエッチング条件により、反応生成物の第１の色の色フィルター１４の側壁への付着の仕方及び付着の量は変化する。 (Partition forming process (second process))
In the step of patterning the color filter 14 of the first color, as shown in FIG. 5A, it is generated when the color filter layer 14a of the first color and the transparent conductive layer 12 are dry etched. A reaction product (an example of a by-product) is formed on the side wall of the color filter 14 of the first color, with the partition wall 17 finally provided between each of the color filters 14, 15, 16. The partition wall 17 is formed of the color filter material of the first color and the reaction product of the transparent conductive layer material and the dry etching gas. At this time, when anisotropic etching is performed, it is important to control a sidewall protective layer formed by attaching a reaction product by dry etching to the sidewall of the color filter 14 of the first color. Also, depending on the dry etching conditions, the manner and amount of adhesion of the reaction product to the side wall of the color filter 14 of the first color changes.
　本実施形態の固体撮像素子の製造方法では、第１の色の色フィルター層１４ａのエッチングを行い、エッチングによって形成された開口部に第２及び第３の色の色フィルター用材料を充填して、多色の色フィルターを形成する。このため、ドライエッチングの際には、第１の色の色フィルター層１４ａを垂直にエッチングし、且つパターンサイズの制御を行う必要がある。そのために、ドライエッチングの際に反応生成物の側壁への付着の仕方及び付着量の制御が必要となる。 In the method of manufacturing the solid-state imaging device according to the present embodiment, the color filter layer 14a of the first color is etched, and the openings formed by the etching are filled with the color filter material of the second and third colors. Form a multicolor color filter. Therefore, in the case of dry etching, it is necessary to vertically etch the color filter layer 14a of the first color and to control the pattern size. Therefore, it is necessary to control the manner and amount of adhesion of the reaction product to the side wall during dry etching.
　ドライエッチングにおいてイオンによる物理的衝撃を用いた反応により、反応生成物の側壁への堆積量（付着量）を増加させることが可能となる。例えば使用するドライエッチング用ガスとしては、ヘリウム（Ｈｅ）、ネオン（Ｎｅ）、アルゴン（Ａｒ）、クリプトン（Ｋｒ）、及びキセノン（Ｘｅ）等の希ガスが考えられ、特にＡｒやＨｅが望ましい。 The reaction using physical impact by ions in dry etching makes it possible to increase the deposition amount (adhesion amount) of the reaction product on the side wall. For example, as a dry etching gas to be used, rare gases such as helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) can be considered, and in particular, Ar and He are preferable.
　本実施形態では、Ａｒ、Ｈｅ等の反応性の少ない元素を含む希ガスを全ガス流量の９０％以上にして、フッ素系又は酸素系等の反応性を有するガス種が１種類以上混合されたドライエッチングガスを用いる。これにより、化学反応を用いてエッチングレートを向上させ、且つ第１の色の色フィルター１４の側壁に付着する反応生成物の量を制御できる。これにより、第１の色の色フィルター１４の側壁に付着させた反応生成物を隔壁１７として形成する。 In the present embodiment, a rare gas containing an element having a low reactivity such as Ar or He is made 90% or more of the total gas flow rate, and one or more types of reactive gas species such as fluorine or oxygen are mixed. A dry etching gas is used. Thereby, a chemical reaction can be used to improve the etching rate, and the amount of reaction products deposited on the side walls of the first color filter 14 can be controlled. Thereby, the reaction product deposited on the side wall of the first color filter 14 is formed as the partition wall 17.
　上記ドライエッチング工程時に発生するプラズマダメージとして、プラズマによるチャージアップに起因する電気的ダメージや、Ａｒイオン等の希ガス粒子の衝突による物理的ダメージやプラズマからの高エネルギーフォトン照射による光照射ダメージの３つが良く知られている。本実施形態によれば、半導体基板１０の表面に導電性があり、エッチング速度が遅い透明導電層１２があることによりこれらのダメージが半導体基板１０に到達するのを抑制する効果が得られる。 Examples of plasma damage generated during the dry etching step include electrical damage due to charge up by plasma, physical damage due to collision of rare gas particles such as Ar ions, and light irradiation damage due to high energy photon irradiation from plasma. One is well known. According to the present embodiment, the transparent conductive layer 12 having conductivity and a slow etching rate on the surface of the semiconductor substrate 10 has the effect of suppressing the damage of the semiconductor substrate 10 from being damaged.
　上記ドライエッチング工程により、色フィルター用材料の残渣を発生させず、ドライエッチングによって発生する反応生成物により形成された隔壁１７を有した第１の色の色フィルター１４を得る。隔壁１７が他色からの漏れ光及び移染を抑制することによって、混色抑制効果となる。 By the above-mentioned dry etching process, a residue of the color filter material is not generated, and the color filter 14 of the first color having the partition wall 17 formed of the reaction product generated by the dry etching is obtained. When the partition wall 17 suppresses the leakage light and the dye transfer from the other colors, the color mixing suppression effect is obtained.
（エッチングマスクパターン除去工程）
　次に、残存しているエッチングマスクパターン２０ａの除去を行う（図５（ｂ）参照）。エッチングマスクパターン２０ａの除去には、例えば薬液や溶剤を用いることで第１の色の色フィルター１４に影響を与えず、エッチングマスクパターン２０ａを溶解、剥離する除去方法が挙げられる。エッチングマスクパターン２０ａを除去する溶剤としては、例えば、Ｎ－メチル－２－ピロリドン、シクロヘキサノン、ジエチレングリコールモノメチルエーテルアセテート、乳酸メチル、乳酸ブチル、ジメチルスルホキシド、ジエチレングリコールジエチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノメチルエーテルアセテート等の有機溶剤を単独又は、複数を混合した混合溶剤が用いられる。また、この際用いる溶剤は、色フィルター用材料に影響を与えないものであることが望ましい。色フィルター用材料に影響を与えないのであれば、酸系の薬品を用いた剥離方法でも問題ない。 (Etching mask pattern removal process)
Next, the remaining etching mask pattern 20a is removed (see FIG. 5B). The removal of the etching mask pattern 20a includes, for example, a removal method in which the etching mask pattern 20a is dissolved and peeled without affecting the first color filter 14 by using a chemical solution or a solvent. As a solvent for removing the etching mask pattern 20a, for example, N-methyl-2-pyrrolidone, cyclohexanone, diethylene glycol monomethyl ether acetate, methyl lactate, butyl lactate, dimethyl sulfoxide, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl A mixed solvent in which an organic solvent such as ether or propylene glycol monomethyl ether acetate is used singly or in combination is used. In addition, it is desirable that the solvent used at this time does not affect the color filter material. If it does not affect the color filter material, there is no problem with the peeling method using an acid type chemical.
　また、溶剤等のウェットプロセス以外の除去方法も用いることができる。光励起や酸素プラズマを用いたレジストの灰化技術であるアッシング技術を用いる方法により、エッチングマスクパターン２０ａを除去することができる。また、これらの方法を組み合わせて用いることもできる。例えば、始めに、光励起や酸素プラズマによる灰化技術であるアッシング技術を用いて、エッチングマスクパターン２０ａの表層のドライエッチングによる変質層を除去した後、溶剤等を用いたウェットエッチングにより残りの層を除去する方法が挙げられる。また、第１の色の色フィルター用材料にダメージの無い範囲であれば、アッシングのみでエッチングマスクパターン２０ａを除去しても構わない。また、アッシング等のドライプロセスだけでなく、ＣＭＰによる研磨工程等を用いても良い。
　上記の工程により、第１の色の色フィルター１４及び隔壁１７のパターニング形成が完了する。 Moreover, the removal methods other than wet processes, such as a solvent, can also be used. The etching mask pattern 20a can be removed by a method using an ashing technique which is a resist ashing technique using light excitation or oxygen plasma. Also, these methods can be used in combination. For example, first, after removing the deteriorated layer by dry etching of the surface layer of the etching mask pattern 20a using ashing technology which is an ashing technology by light excitation or oxygen plasma, the remaining layers are wet etched using a solvent or the like. The method of removing is mentioned. Further, the etching mask pattern 20a may be removed only by ashing as long as there is no damage to the color filter material of the first color. In addition to the dry process such as ashing, a polishing process by CMP may be used.
The above steps complete the patterning of the color filters 14 and the partitions 17 of the first color.
（第２以降の色フィルターのパターンの形成工程について（第３の工程））
　次に、隔壁形成工程の後に、図６に示すように、第１の色の色フィルター１４とは異なる色を含む第２、第３の色の色フィルター１５、１６を形成する。
　第１の色の色フィルター１４及び隔壁１７のパターンをガイドパターンとすると共に、第２、第３の色の色フィルター１５、１６に光硬化性樹脂を含んだ感光性色フィルター用材料を用いて形成し、従来手法で選択的に露光してパターンを形成する手法である。 (On the formation process of the second and subsequent color filter patterns (third process))
Next, after the partition wall forming process, as shown in FIG. 6, color filters 15 and 16 of second and third colors including colors different from the color filter 14 of the first color are formed.
The pattern of the first color filter 14 and the partition wall 17 is used as a guide pattern, and a photosensitive color filter material containing a photocurable resin for the second and third color filters 15 and 16 is used. It is a method of forming and exposing selectively by a conventional method to form a pattern.
　まず図６（ａ）に示すように、第１の色の色フィルター１４及び隔壁１７をパターン形成した半導体基板１０の表面全面に、第２の色の色フィルター用材料として感光性色フィルター用材料を塗布、乾燥を行い第２の色の色フィルター層１５ａを形成する。この際用いる感光性色フィルター用材料は、光照射により硬化するネガ型の感光性成分を含有する。 First, as shown in FIG. 6A, a photosensitive color filter material is formed on the entire surface of the semiconductor substrate 10 on which the color filters 14 and the partitions 17 of the first color are formed as a second color filter material. To form a second color filter layer 15a. The photosensitive color filter material used at this time contains a negative photosensitive component that is cured by light irradiation.
　この際、第１の色の色フィルター１４の膜厚をＡ［ｎｍ］、透明導電層１２の膜厚をＢ［ｎｍ］、第２の色の色フィルター１５の膜厚をＣ１［ｎｍ］とした場合に、下記（１）式～（３ａ）式を満足するように、第２の色の色フィルター１５の膜厚Ｃ１を設定する。
　２００［ｎｍ］≦Ａ≦７００［ｎｍ］　・・・（１）
　０［ｎｍ］＜Ｂ≦２００［ｎｍ］　　　・・・（２）
　Ａ＋Ｂ－２００［ｎｍ］≦Ｃ１≦Ａ＋Ｂ＋２００　・・・（３ａ）
　図６では、Ａ＝Ｃ１の場合を例示しているが、（３ａ）式のように膜厚Ｃ１は、（Ａ＋Ｂ）±２００［ｎｍ］の範囲に収まっていればよい。
　第２の色の色フィルター１５として、この膜厚Ｃ１の範囲であれば、硬化に十分な熱硬化性樹脂及び光硬化性樹脂を含みながら、所望の分光特性が得られる顔料濃度を有した色フィルターとする事ができる。 At this time, the film thickness of the color filter 14 of the first color is A [nm], the film thickness of the transparent conductive layer 12 is B [nm], and the film thickness of the color filter 15 of the second color is C1 [nm]. In this case, the film thickness C1 of the color filter 15 of the second color is set so as to satisfy the following equations (1) to (3a).
200 [nm] ≦ A ≦ 700 [nm] (1)
0 [nm] <B ≦ 200 [nm] (2)
A + B-200 [nm] ≦ C1 ≦ A + B + 200 (3a)
Although FIG. 6 exemplifies the case of A = C1, the film thickness C1 may be within the range of (A + B) ± 200 [nm] as in the expression (3a).
A color filter 15 having a pigment concentration capable of obtaining desired spectral characteristics while containing a thermosetting resin and a photocurable resin sufficient for curing within the range of the film thickness C1 as the color filter 15 of the second color It can be a filter.
　次に、図６（ｂ）に示すように、第２の色の色フィルター１５を形成する部分に対して、フォトマスクを用いて露光を行い、第２の色の色フィルター層１５ａのパターン領域を選択的に光硬化させて、現像工程で選択的に露光されていない第２の色の色フィルター層１５ａのパターン領域外（第３の色の色フィルタ形成位置）を除去する。次に、図６（ｃ）に示すように露光・現像を行った第２の色の色フィルター層１５ａのパターン領域と半導体基板１０との密着性向上及び実デバイス利用での耐熱性を向上させるために、高温加熱での硬化処理を行うことで第２の色の色フィルター層１５ａを硬化させる。これにより、第２の色の色フィルター１５のパターンを形成する。この際、硬化に用いる温度は、２００℃以上が好ましい。 Next, as shown in FIG. 6 (b), a portion on which the color filter 15 of the second color is to be formed is exposed using a photomask to form a pattern area of the color filter layer 15a of the second color. Is selectively photocured to remove the outside of the pattern area of the color filter layer 15a of the second color which is not selectively exposed in the development step (the color filter forming position of the third color). Next, as shown in FIG. 6C, the adhesion between the pattern area of the color filter layer 15a of the second color subjected to exposure and development and the semiconductor substrate 10 is improved, and the heat resistance in actual device utilization is improved. In order to achieve this, the second color filter layer 15a is cured by performing a curing process at a high temperature. Thereby, the pattern of the color filter 15 of the second color is formed. At this time, the temperature used for curing is preferably 200 ° C. or higher.
　次に、図７（ａ）に示すように、第３の色の色フィルター用材料を半導体基板１０の全面に塗布、乾燥を行う。すなわち第２の色の色フィルター層１５ａのパターン領域外の全面に第３の色の色フィルター用材料を塗布して、第３の色の色フィルター層１６ａを形成する。次に、図７（ｂ）に示すように、第３の色の色フィルター層１６ａのうちの第３の色の色フィルター１６を形成するパターン領域を選択的に露光し、第３の色の色フィルター層１６ａを光硬化させて、現像によって露光されていない第３の色の色フィルター層１６ａのパターン領域外を除去する。次に、図７（ｃ）のように、露光・現像を行った第３の色の色フィルター層１６ａの一部と半導体基板１０との密着性向上及び実デバイス利用での耐熱性を向上させるために、高温加熱での硬化処理を行うことで第３の色の色フィルター層１６ａを硬化させる。これにより、第３の色の色フィルター１６を形成する。
　なお、この第２の色の色フィルター１５以降のパターン形成工程を繰り返すことで、所望の色数の色フィルターを形成することが可能である。 Next, as shown in FIG. 7A, the color filter material of the third color is applied to the entire surface of the semiconductor substrate 10 and dried. That is, the third color filter material is applied to the entire surface outside the pattern area of the second color filter layer 15a to form the third color filter layer 16a. Next, as shown in FIG. 7B, the pattern area forming the color filter 16 of the third color in the color filter layer 16a of the third color is selectively exposed. The color filter layer 16a is photocured to remove the outside of the pattern area of the color filter layer 16a of the third color not exposed by development. Next, as shown in FIG. 7C, the adhesion between the semiconductor substrate 10 and a part of the third color filter layer 16a subjected to exposure and development is improved, and the heat resistance in actual device utilization is improved. In order to achieve this, the third color filter layer 16a is cured by performing a curing process at a high temperature. Thereby, the color filter 16 of the third color is formed.
In addition, it is possible to form the color filter of a desired number of colors by repeating the pattern formation process after the color filter 15 of this 2nd color.
　この際、第３の色の色フィルター１６の膜厚をＣ２［ｎｍ］とした場合に、下記（１）式～（３ｂ）式を満足するように、第３の色の色フィルター１６の膜厚Ｃ２を設定する。
　２００［ｎｍ］≦Ａ≦７００［ｎｍ］　・・・（１）
　０［ｎｍ］＜Ｂ≦２００［ｎｍ］　　　・・・（２）
　Ａ＋Ｂ－２００［ｎｍ］≦Ｃ２≦Ａ＋Ｂ＋２００　・・・（３ｂ）
　図７では、Ａ＝Ｃ２の場合を例示しているが、（３ｂ）式のように膜厚Ｃ２は、（Ａ＋Ｂ）±２００［ｎｍ］の範囲に収まっていればよい。
　第３の色の色フィルター１６として、この膜厚Ｃ２の範囲であれば、硬化に十分な熱硬化性樹脂及び光硬化性樹脂を含みながら、所望の分光特性が得られる顔料濃度を有した色フィルターとする事ができる。 Under the present circumstances, when the film thickness of the color filter 16 of 3rd color is set to C2 [nm], the film of the color filter 16 of 3rd color so that the following formula (1)-(3b) may be satisfied. Set thickness C2.
200 [nm] ≦ A ≦ 700 [nm] (1)
0 [nm] <B ≦ 200 [nm] (2)
A + B-200 [nm] ≦ C2 ≦ A + B + 200 (3b)
Although FIG. 7 exemplifies the case of A = C2, the film thickness C2 may be within the range of (A + B) ± 200 [nm] as in the expression (3b).
A color filter 16 having a pigment concentration capable of obtaining desired spectral characteristics while containing a thermosetting resin and a photocurable resin sufficient for curing within the range of this film thickness C2 as the third color filter 16 It can be a filter.
　次いで、図８（ａ）に示すように、形成された色フィルター１４，１５，１６及び隔壁１７上に平坦化層１３を形成する。平坦化層１３は、例えばアクリル系樹脂等の樹脂材料を一つ又は複数含んだ樹脂を用いて形成することができる。複数色の各色フィルター１４，１５，１６及び隔壁１７上に樹脂材料を塗布して加熱により硬化することで、平坦化層１３を形成することができる。また、平坦化層１３は、例えば酸化物又は窒化物等の化合物を用いて形成することができる。この場合、平坦化層１３は、蒸着、スパッタ、ＣＶＤ等の各種の成膜方法により形成することができる。 Next, as shown in FIG. 8A, the planarizing layer 13 is formed on the formed color filters 14, 15 and 16 and the partition wall 17. The planarization layer 13 can be formed using, for example, a resin containing one or more resin materials such as an acrylic resin. By applying a resin material on each color filter 14, 15, 16 of a plurality of colors and the partition wall 17 and curing the resin material by heating, the planarization layer 13 can be formed. The planarization layer 13 can be formed using, for example, a compound such as an oxide or a nitride. In this case, the planarization layer 13 can be formed by various film formation methods such as vapor deposition, sputtering, and CVD.
　最後に、図８（ｂ）に示すように、平坦化層１３上に、マイクロレンズ１８を形成する。マイクロレンズ１８は、熱フローを用いた作製方法、グレートーンマスクによるマクロレンズ作製方法、ドライエッチングを用いた平坦化層１３へのマイクロレンズ転写方法等の公知の技術により形成される。
　平坦化層１３の膜厚は、例えば１［ｎｍ］以上３００［ｎｍ］以下である。好ましくは１００［ｎｍ］以下、より好ましくは６０［ｎｍ］以下である。 Finally, as shown in FIG. 8B, the microlenses 18 are formed on the planarization layer 13. The microlenses 18 are formed by known techniques such as a manufacturing method using heat flow, a macro lens manufacturing method using a gray tone mask, and a microlens transfer method to the planarizing layer 13 using dry etching.
The film thickness of the planarization layer 13 is, for example, not less than 1 nm and not more than 300 nm. Preferably it is 100 [nm] or less, More preferably, it is 60 [nm] or less.
　ドライエッチングによるパターニング技術を用いてマイクロレンズを形成する方法は、図９（ａ）に示すように、先ず最終的にマイクロレンズとなる平坦化層１３を複数色の各色フィルター１４，１５，１６及び隔壁上に形成する。 As shown in FIG. 9A, in the method of forming the microlenses using the patterning technique by dry etching, first, the planarizing layer 13 to be the microlenses finally becomes the microlenses of each color filter 14, 15, 16 of a plurality of colors and Form on the partition wall.
　次に、図９（ｂ）に示すように、平坦化層１３の上にマイクロレンズの母型を形成するためのマイクロレンズ母型層１８ａを塗布して形成する。マイクロレンズ母型層１８ａの材料は、アクリル系樹脂等の樹脂材料を一つもしくは複数含んだ樹脂を用いる。 Next, as shown in FIG. 9B, a microlens matrix layer 18 a for forming a matrix of microlenses is coated and formed on the planarization layer 13. As a material of the microlens matrix layer 18a, a resin containing one or more resin materials such as an acrylic resin is used.
　次に、図１０（ａ）に示すように、フォトマスク（図示せず）を用いて露光し、熱フロー法によってマイクロレンズのレンズ母型１８ｂを形成する。
　次に、図１０（ｂ）に示すように、レンズ母型１８ｂをマスクとして、ドライエッチングの手法によってレンズ母型１８ｂの形状を平坦化層１３に転写する。レンズ母型１８ｂの高さや材料を選択し、ドライエッチング条件を調整することで、適正なレンズ形状のマイクロレンズ１８を平坦化層１３に転写することができる。これにより、平坦化層１３と一体化された複数のマイクロレンズ１８が形成される。
　上記の方法を用いることで、制御性良くマイクロレンズ１８を形成することが可能となる。この手法を用いて、マイクロレンズ１８のレンズトップからレンズボトムの高さが３００～８００ｎｍの膜厚となるようにマイクロレンズ１８を作製することが望ましい。 Next, as shown in FIG. 10A, exposure is performed using a photomask (not shown), and a lens base 18b of a microlens is formed by a heat flow method.
Next, as shown in FIG. 10B, the shape of the lens base 18b is transferred to the planarizing layer 13 by dry etching using the lens base 18b as a mask. By selecting the height and material of the lens base 18 b and adjusting the dry etching conditions, the microlenses 18 having an appropriate lens shape can be transferred to the planarizing layer 13. Thereby, a plurality of microlenses 18 integrated with the planarization layer 13 are formed.
By using the above method, it is possible to form the microlens 18 with good controllability. It is desirable to fabricate the microlens 18 so that the film thickness of the lens top of the microlens 18 to the lens bottom becomes 300 to 800 nm using this method.
（４色以上の複数色の色フィルターの場合）
　４色以上の複数色の色フィルターを製造する場合は、第１の色の色フィルター形成時に、４色以上の色フィルター形成箇所を開口するように形成し、第三の色フィルター以降の工程を上述した第二の色フィルター１５の形成工程と同様の処理を繰り返すことで形成することができる。また、最後の色の色フィルターを形成する工程で上述した第三の色フィルター１６の形成工程と同様の処理を行う。これにより、４色以上の複数色の色フィルターを製造することができる。 (In the case of multiple color filters of 4 or more colors)
In the case of producing a color filter of four or more colors, when forming the color filter of the first color, it is formed so as to open the portion where the color filter of four or more colors is formed. It can form by repeating the process similar to the formation process of the 2nd color filter 15 mentioned above. Further, in the process of forming the last color filter, the same process as the process of forming the third color filter 16 described above is performed. Thereby, a color filter of four or more colors can be manufactured.
　以上の工程により、本実施形態の固体撮像素子１が完成する。 The solid-state imaging device 1 of the present embodiment is completed by the above steps.
　本実施形態では、第１の色の色フィルター１４を、最も専有面積の広い色フィルターとすることが好ましい。そして、第２の色の色フィルター１５及び第３の色の色フィルター１６は、感光性を有したカラーレジストを用いてフォトリソグラフィによりそれぞれ形成する。 In the present embodiment, it is preferable to use the color filter 14 of the first color as the color filter with the largest area. The second color filter 15 and the third color filter 16 are formed by photolithography using a photosensitive color resist.
　感光性を有したカラーレジストを用いる技術は従来の色フィルターパターンの製造技術である。第１の色の色フィルター用材料は、透明導電層１２の全面に塗布後、高温で加熱するため、半導体基板１０及び透明導電層１２との密着性を良くすることができる。そのため、密着性が良好であり、矩形性良く形成した第１の色の色フィルター１４及び隔壁１７のパターンをガイドパターンとして、隔壁１７によって四辺が囲われた場所を埋めるように第２、第３の色の色フィルター１５、１６を形成することができる。そのため第２以降の色フィルターに感光性を持たせたカラーレジストを用いた場合でも、従来のように解像性を重視したカラーレジストとする必要はない。このため、光硬化性樹脂中の光硬化成分を少なくすることができるため、色フィルター用材料中の顔料の割合を多くでき、色フィルター１５、１６の薄膜化に対応できる。 The technology using a photosensitive color resist is a conventional color filter pattern manufacturing technology. The color filter material of the first color is coated on the entire surface of the transparent conductive layer 12 and then heated at a high temperature, so that the adhesion with the semiconductor substrate 10 and the transparent conductive layer 12 can be improved. Therefore, the adhesion is good, and the patterns of the color filters 14 and partitions 17 of the first color formed with good rectangularity are used as guide patterns, and the second and third to fill the places where the four sides are surrounded by the partitions 17. Color filters 15, 16 can be formed. Therefore, even when using a color resist having photosensitivity for the second and subsequent color filters, it is not necessary to use a color resist that places emphasis on resolution as in the prior art. For this reason, since the photocurable component in the photocurable resin can be reduced, the proportion of the pigment in the color filter material can be increased, and thin film formation of the color filters 15, 16 can be coped with.
　本実施形態では、第１の色の色フィルター１４に熱硬化性樹脂と光硬化性樹脂の両方を用いている。第１の色の色フィルター１４は、光硬化に関与する樹脂成分等の含有率が少なく、かつ顔料含有率の高い色フィルター用材料で形成することが望ましい。特に、１色目の色フィルター用材料における顔料の含有率を７０質量％以上に構成することが望ましい。それにより、第１の色の色フィルター用材料に、従来の感光性カラーレジストを用いたフォトリソグラフィプロセスでは硬化不充分になってしまう濃度の顔料が含まれていても、第１の色の色フィルター１４を精度良く、残渣や剥がれもなく形成することができる。 In the present embodiment, both the thermosetting resin and the photocurable resin are used for the color filter 14 of the first color. The color filter 14 of the first color is desirably formed of a color filter material having a low content of resin components and the like involved in photocuring and a high pigment content. In particular, it is desirable to configure the content of the pigment in the color filter material for the first color to 70% by mass or more. Thereby, the color filter material of the first color is the color of the first color even if it contains a pigment at a concentration that would be insufficiently cured by the conventional photolithography process using a photosensitive color resist The filter 14 can be formed precisely with no residue or peeling.
　本実施形態では、第１の色の色フィルター１４に硬化性、溶剤耐性を向上させるため、熱硬化樹脂と光硬化性樹脂を併用する材料を用いたが、求める分光特性によっては、顔料濃度や、経時特性などを重視して、熱硬化性樹脂のみ又は、光硬化性樹脂のみで材料を形成しても問題ない。熱硬化性樹脂のみを用いる場合は、顔料濃度を増やすことが可能となるため、色フィルターの薄膜化が可能となる。一方光硬化性樹脂のみを用いる場合は、溶剤耐性が低下しやすいが、経時特性などの面で材料設計の自由度が向上する利点がある。 In the present embodiment, in order to improve the curability and solvent resistance of the color filter 14 of the first color, a material in which a thermosetting resin and a photocurable resin are used in combination is used. There is no problem if the material is formed of only the thermosetting resin or only the photocurable resin, with emphasis on time-lapse characteristics and the like. In the case of using only the thermosetting resin, it is possible to increase the pigment concentration, and therefore, it is possible to make the color filter thin. On the other hand, when only a photocurable resin is used, the solvent resistance tends to decrease, but there is an advantage that the degree of freedom in material design is improved in terms of temporal characteristics and the like.
　本実施形態では、第１の色の色フィルター１４と第２及び第３の色の色フィルター１５、１６との間に隔壁１７が構成されて、隔壁１７が他色からの漏れ光及び移染を抑制するため、混色が抑制される。 In the present embodiment, the partition wall 17 is formed between the color filter 14 of the first color and the color filters 15 and 16 of the second and third colors, and the partition wall 17 is leaked light from other colors and migration. In order to suppress the color mixing, color mixing is suppressed.
　本実施形態では、第１の色の色フィルター１４の下層に透明導電層１２があることにより、第２及び第３の色の色フィルター１５、１６の形成箇所を開口するドライエッチング工程時のプラズマダメージを低減でき、エッチング速度が遅い透明導電層がエッチングストッパーの役割を果たすことで、半導体基板１０をドライエッチングする可能性も低減できる。 In this embodiment, since the transparent conductive layer 12 is provided under the first color filter 14, plasma in the dry etching process for opening the formation locations of the second and third color filters 15 and 16. The damage can be reduced, and the transparent conductive layer having a slow etching rate plays the role of an etching stopper, whereby the possibility of dry etching the semiconductor substrate 10 can be reduced.
　以上のように、本実施形態によれば、各色フィルターの膜厚を全て薄膜化しマイクロレンズトップからデバイスまでの総距離を短くし、さらに複数色の色フィルター間に隔壁を有する事によって混色を抑制でき、パターン配置した全ての色フィルターが高感度化した高精細な固体撮像素子を提供することが可能となる。 As described above, according to the present embodiment, all the film thickness of each color filter is made thin, the total distance from the microlens top to the device is shortened, and color separation is suppressed by having partitions between color filters of a plurality of colors. It is possible to provide a high-definition solid-state imaging device in which all color filters arranged in a pattern are highly sensitive.
　「第２の実施形態」
　以下、図１１から図１４を参照して、本発明の第２の実施形態に係る固体撮像素子及び固体撮像素子の製造方法について説明する。図１１に示すように、本発明の第２の実施形態に係る固体撮像素子２は、第１の実施形態の構造で、透明導電層１２と第１の色の色フィルター１４との間に透明樹脂層３０がある構造である。固体撮像素子２の各色フィルター１４，１５，１６の平面配列は、図２に示すベイヤー配列である。
　第２の実施形態は、第１の色の色フィルターの工程までが異なるため、図を用いて示す。 "Second embodiment"
Hereinafter, with reference to FIGS. 11 to 14, a solid-state imaging device and a method of manufacturing the solid-state imaging device according to the second embodiment of the present invention will be described. As shown in FIG. 11, the solid-state imaging device 2 according to the second embodiment of the present invention has the structure of the first embodiment, and is transparent between the transparent conductive layer 12 and the color filter 14 of the first color. It is a structure with the resin layer 30. The planar arrangement of the color filters 14, 15, 16 of the solid-state imaging device 2 is the Bayer arrangement shown in FIG.
The second embodiment is illustrated using figures, as the process up to the first color filter is different.
　＜固体撮像素子の構成＞
　本実施形態に係る固体撮像素子２は、第１の色の色フィルター１４の形成前に透明樹脂層３０を形成する点に特徴を有している。透明樹脂層３０を導入することで、色フィルターの密着性、半導体基板１０の平坦性、色フィルター材料エッチング後の残渣性を改善、隔壁１７に含有する材料を変えることができ、第１の色の色フィルター１４の形成が容易となる利点がある。 <Configuration of solid-state imaging device>
The solid-state imaging device 2 according to the present embodiment is characterized in that the transparent resin layer 30 is formed before the formation of the color filter 14 of the first color. By introducing the transparent resin layer 30, it is possible to improve the adhesion of the color filter, the flatness of the semiconductor substrate 10, and the residual property after etching of the color filter material, and change the material contained in the partition wall 17. There is an advantage that the formation of the color filter 14 is easy.
　本実施形態に係る固体撮像素子２は、図１１に示すように、二次元的に配置された複数の光電変換素子１１を有する半導体基板１０と、半導体基板１０の上方に配置された複数のマイクロレンズ１８からなるマイクロレンズ群１８０と、半導体基板１０とマイクロレンズ１８との間に設けられた、透明導電層１２、色フィルター層１００及び隔壁１７とを備えている。色フィルター層１００は、複数色の各色フィルター１４，１５，１６が所定の規則パターンで配置されて構成される。隔壁１７は、複数色の各色フィルター１４，１５，１６のそれぞれの間に配置される。また、色フィルター層１００と複数のマイクロレンズ１８からなるマイクロレンズ群１８０との間に、平坦化層１３が形成されている。 As shown in FIG. 11, the solid-state imaging device 2 according to the present embodiment includes a semiconductor substrate 10 having a plurality of photoelectric conversion elements 11 two-dimensionally arranged, and a plurality of micro-elements disposed above the semiconductor substrate 10. A microlens group 180 consisting of a lens 18 and a transparent conductive layer 12, a color filter layer 100 and a partition 17 provided between the semiconductor substrate 10 and the microlens 18 are provided. The color filter layer 100 is configured by arranging the color filters 14, 15, 16 of a plurality of colors in a predetermined regular pattern. The partition wall 17 is disposed between each of the color filters 14, 15, 16 of a plurality of colors. Further, the flattening layer 13 is formed between the color filter layer 100 and the microlens group 180 including the plurality of microlenses 18.
　ここで、第２の実施形態に係る固体撮像素子２において、第１の実施形態に係る固体撮像素子１の各部と同様の構成である場合には、第１の実施形態に用いた参照符号と同じ参照符号を付すものとする。すなわち、光電変換素子１１を有する半導体基板１０、透明導電層１２、色フィルター１４、１５、１６、隔壁１７、平坦化層１３及びマイクロレンズ１８のそれぞれは、第１の実施形態に係る固体撮像素子１の各部と同様の構成である。このため、第１の実施形態に係る固体撮像素子１の各部と共通する部分についての詳細な説明については省略する。その他の実施形態でも同様である。 Here, in the solid-state imaging device 2 according to the second embodiment, when it has the same configuration as each part of the solid-state imaging device 1 according to the first embodiment, the reference numerals used in the first embodiment and The same reference signs shall be given. That is, each of the semiconductor substrate 10 having the photoelectric conversion element 11, the transparent conductive layer 12, the color filters 14, 15, 16, the partition wall 17, the planarization layer 13 and the microlens 18 is a solid-state imaging device according to the first embodiment. The configuration is the same as that of each part of 1. Therefore, the detailed description of the parts common to the respective parts of the solid-state imaging device 1 according to the first embodiment will be omitted. The same applies to the other embodiments.
　＜固体撮像素子の製造方法＞
　次に、図１２から図１４を参照して、本実施形態の固体撮像素子２の製造方法について説明する。 <Method of manufacturing solid-state imaging device>
Next, a method of manufacturing the solid-state imaging device 2 according to the present embodiment will be described with reference to FIGS. 12 to 14.
（第１の色の色フィルター層形成工程（第１の工程））
　第１の色の色フィルター層形成工程では、複数の光電変換素子１１を二次元的に配置した半導体基板１０に透明導電層１２を形成し、透明導電層１２上に透明樹脂層３０を形成し、第１の色の色フィルター１４用の塗布液を塗布し硬化させて、透明導電層１２、透明樹脂層３０及び第１の色の色フィルター層１４ａをこの順に形成した後、第１の色の色フィルター１４の配置位置以外の第１の色の色フィルター層１４ａ部分及び第１の色の色フィルター層１４ａ部分の下層に位置する透明樹脂層３０をドライエッチングによって除去して第１の色の色フィルター１４をパターン形成する。以下、第１の色の色フィルター層形成工程の詳細について説明する。 (Step of forming first color filter layer (first step))
In the color filter layer forming step of the first color, the transparent conductive layer 12 is formed on the semiconductor substrate 10 on which the plurality of photoelectric conversion elements 11 are two-dimensionally arranged, and the transparent resin layer 30 is formed on the transparent conductive layer 12 The coating liquid for the first color filter 14 is applied and cured to form the transparent conductive layer 12, the transparent resin layer 30, and the first color filter layer 14a in this order, and then the first color is formed. The transparent resin layer 30 located under the first color filter layer 14a portion and the first color color filter layer 14a portion other than the arrangement position of the color filter 14 is removed by dry etching to form a first color Pattern the color filter 14 of FIG. Hereinafter, the details of the color filter layer forming step of the first color will be described.
　図１２（ａ）に示すように、二次元的に配置された複数の光電変換素子１１を有する半導体基板１０の上に透明導電層１２を形成する。透明導電層１２は、半導体基板１０の表面保護、平坦化及び、プラズマエッチングによる帯電（チャージアップ）等のダメージ低減のために設けられた層である。すなわち、透明導電層１２は、光電変換素子１１の作製による半導体基板１０の上面の凹凸を低減し、色フィルター用材料との密着性を向上させ、第１の色の色フィルター層１４ａをパターン加工する際のプラズマエッチングの保護層となる。透明導電層１２の材料及び、形成方法は第１の実施形態で説明したものを使用する。このあと、前述した第１の実施形態と同様の方法で、半導体基板１０の電極部などの上の透明導電層１２を除去する。 As shown to Fig.12 (a), the transparent conductive layer 12 is formed on the semiconductor substrate 10 which has the several photoelectric conversion element 11 arrange | positioned two-dimensionally. The transparent conductive layer 12 is a layer provided for surface protection of the semiconductor substrate 10, planarization, and damage reduction such as charging (charge up) by plasma etching. That is, the transparent conductive layer 12 reduces unevenness of the upper surface of the semiconductor substrate 10 by the preparation of the photoelectric conversion element 11, improves the adhesion with the color filter material, and patterns the color filter layer 14a of the first color. It becomes a protective layer of plasma etching at the time of etching. The material and formation method of the transparent conductive layer 12 use what was demonstrated in 1st Embodiment. Thereafter, the transparent conductive layer 12 on the electrode portion or the like of the semiconductor substrate 10 is removed by the same method as in the first embodiment described above.
　次に、図１２（ｂ）に示すように、透明導電層１２の上に透明樹脂層３０を形成する。透明樹脂層３０は、例えばアクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂、フェノールノボラック系樹脂、ポリエステル系樹脂、ウレタン系樹脂、メラミン系樹脂、尿素系樹脂、スチレン系樹脂及びケイ素系樹脂等の樹脂を一又は複数含んだ樹脂により形成される。透明樹脂層３０の膜厚は、例えば１［ｎｍ］以上３００［ｎｍ］以下である。混色防止の観点からは薄いほど好ましく、望ましくは、５ｎｍから６０ｎｍである。 Next, as shown in FIG. 12B, the transparent resin layer 30 is formed on the transparent conductive layer 12. The transparent resin layer 30 is, for example, a resin such as an acrylic resin, an epoxy resin, a polyimide resin, a phenol novolac resin, a polyester resin, a urethane resin, a melamine resin, a urea resin, a urea resin, a styrene resin, and a silicon resin. It is formed of a resin containing one or more. The film thickness of the transparent resin layer 30 is, for example, 1 nm or more and 300 nm or less. From the viewpoint of preventing color mixing, the thinner, the better, and the thickness is preferably 5 nm to 60 nm.
　次に、図１２（ｃ）に示すように、透明樹脂層３０の上に第１の色の色フィルター層１４ａを形成し、図１２（ｄ）に示すように、形成された第１の色の色フィルター層１４ａを加熱して硬化し、図１２（ｅ）に示すように、効果された第１の色の色フィルター層１４ａの上に感光性樹脂材料を塗布して乾燥し、感光性樹脂材料層を形成し、エッチングマスク２０を形成する。第１の色の色フィルター層１４ａは、最終的に形成される第１の色の色フィルター１４と同じか僅かに厚い膜厚を有するが、図１２及び後述する図１３では説明の便宜上、第１の色の色フィルター１４（図１４参照）よりも膜厚が薄い状態で図示されている。 Next, as shown in FIG. 12 (c), the color filter layer 14a of the first color is formed on the transparent resin layer 30, and as shown in FIG. 12 (d), the first color formed. The color filter layer 14a is heated and cured, and as shown in FIG. 12 (e), a photosensitive resin material is applied on the color filter layer 14a of the first color that has been effected and dried. A resin material layer is formed, and an etching mask 20 is formed. The color filter layer 14a of the first color has the same or slightly thicker film thickness as the color filter 14 of the first color to be finally formed, but in FIG. 12 and FIG. The film thickness is shown to be thinner than the color filter 14 of one color (see FIG. 14).
　次に、図１３（ａ）に示すように、フォトマスク（図示せず）を用いて、第２及び第３の色の色フィルター１５，１６の形成箇所が開口するように露光し、現像することで、図１３（ｂ）に示すように、開口部２０ｂを有するエッチングマスクパターン２０ａを形成する。これら工程は前述した第１の実施形態の工程と同様である。 Next, as shown in FIG. 13A, a photomask (not shown) is used to expose and develop so that the formation locations of the color filters 15 and 16 of the second and third colors are opened. Thus, as shown in FIG. 13B, the etching mask pattern 20a having the opening 20b is formed. These steps are the same as the steps of the first embodiment described above.
　次に、エッチングマスクパターン２０ａを用いて、第１の実施形態で説明したドライエッチングガスを用いたドライエッチングにより、図１４（ａ）に示すように、開口部２０ｂから露出する第１の色の色フィルター層１４ａの一部分を除去する。 Next, using the etching mask pattern 20a, as shown in FIG. 14A, the first color of the first color exposed from the opening 20b by dry etching using the dry etching gas described in the first embodiment. A portion of the color filter layer 14a is removed.
　本実施形態では、第１の色の色フィルター１４の下層に透明樹脂層３０があるため、透明樹脂層３０をエッチング出来るドライエッチングガスで、エッチングを行うことが望ましい。また、エッチングマスクパターン２０ａを用いて、第１の色の色フィルター層１４ａを矩形性良くエッチングすることが望ましい。本実施形態では初期の段階で全ガス流量の９０％以上を希ガス等のイオンの物理的衝撃が主体でエッチングを行うガスとし、そこにフッ素系ガスや酸素系ガスを混合したエッチングガスを用いることで、化学反応も利用してエッチングレートを向上させる。 In this embodiment, since the transparent resin layer 30 is located under the first color filter 14, it is desirable to perform the etching with a dry etching gas that can etch the transparent resin layer 30. Further, it is desirable to etch the color filter layer 14a of the first color with good rectangularity by using the etching mask pattern 20a. In the present embodiment, 90% or more of the total gas flow rate in the initial stage is a gas that performs etching mainly by physical impact of ions such as a rare gas, and uses an etching gas in which a fluorine-based gas or an oxygen-based gas is mixed therein. Thus, the chemical reaction is also used to improve the etching rate.
　ドライエッチングガスに希ガスを多く用いることで、希ガスイオンの物理的衝撃による効果により、垂直にエッチングが進行する異方性エッチングが進行しやすい条件となる。そのため、色フィルターのエッチングの初期では、希ガスが多い条件でエッチングを実施する。具体的には、希ガスの単ガス又は反応性ガスと希ガスの混合ガスの全ガス流量の９０％以上が希ガスで第１の色の色フィルター層１４ａの一部または全てをエッチングする。この時、第１の色の色フィルター層１４ａがまだ残っている段階でエッチングを途中で止めて、物理的にエッチングを行う希ガスの割合を低減してエッチングすることが望ましい。具体的には、第１の色の色フィルター層１４ａの膜厚の５０％から９５％をエッチングした状態であり、より好ましくは、７０％から９０％をエッチングした段階で、エッチングガスの条件を切り替えることが望ましい。 By using a large amount of the rare gas as the dry etching gas, anisotropic etching in which the etching progresses vertically is likely to progress because of the effect of physical impact of the rare gas ions. Therefore, in the initial stage of the etching of the color filter, the etching is performed under the condition of a large amount of rare gas. Specifically, 90% or more of the total gas flow rate of the single gas of the rare gas or the mixed gas of the reactive gas and the rare gas etches part or all of the color filter layer 14a of the first color with the rare gas. At this time, it is desirable to stop the etching in the middle when the color filter layer 14a of the first color is still left, and to reduce the ratio of the rare gas which physically etches to perform the etching. Specifically, 50% to 95% of the film thickness of the first color filter layer 14a is etched, more preferably, 70% to 90% of the film thickness of the first color filter layer 14a is etched. It is desirable to switch.
　次の段階では、残っている第１の色の色フィルター層１４ａ及び透明樹脂層３０をエッチングして、下層の透明導電層１２で停止するようにする。透明導電層１２のエッチングが遅いガスとして、酸素、フッ素系ガスを用いて残留している第１の色の色フィルター層１４ａ及び透明樹脂層３０を全てエッチングする。この際用いる条件は、透明導電層１２のエッチング速度が遅く、透明樹脂層３０は化学的エッチング反応で除去され易いため、第１の色の色フィルター１４を残渣なくエッチングし、透明導電層１２が無くならない時間で行う。図１４では透明導電層１２がドライエッチングガスに耐性があり、一部以外ほぼエッチングが進んでいない構成を示している。
　具体的には、第１の色の色フィルター層１４ａの残り膜厚量の２倍から３倍程度の膜厚をエッチングする時間で調整を行うことで、第１の色の色フィルター層１４ａ及び透明樹脂層３０が残渣無くエッチングすることが望ましい。 In the next step, the remaining first color filter layer 14 a and the transparent resin layer 30 are etched to stop at the underlying transparent conductive layer 12. The first color color filter layer 14 a and the transparent resin layer 30 remaining are etched using oxygen and a fluorine-based gas as a gas for which the transparent conductive layer 12 is etched slowly. The conditions used here are that the etching rate of the transparent conductive layer 12 is low and the transparent resin layer 30 is easily removed by a chemical etching reaction, so the color filter 14 of the first color is etched without residue and the transparent conductive layer 12 Do it in time that will not disappear. FIG. 14 shows a configuration in which the transparent conductive layer 12 is resistant to the dry etching gas and the etching is hardly advanced except for a part.
Specifically, the color filter layer 14a of the first color and the first color filter layer 14a are adjusted by adjusting the time for etching the film thickness twice to three times the remaining film thickness of the first color filter layer 14a. It is desirable that the transparent resin layer 30 be etched without residue.
　このエッチングの際、第１の色の色フィルター１４以外の色フィルター形成箇所は、透明樹脂層３０がエッチングで除去されている。その為、図１１に示すように、複数色の色フィルターの上部の高さをそろえた場合、第１の色の色フィルター１４に対して、第２の色以降の色フィルターの膜厚は、透明樹脂層３０の膜厚分膜厚を厚く調整をすることが可能となる。その為、第２の色以降の色フィルターに光硬化性樹脂を用いても、膜厚分顔料濃度の調整範囲が広がる利点がある。 At the time of this etching, the transparent resin layer 30 is removed by etching at the color filter formation locations other than the color filter 14 of the first color. Therefore, as shown in FIG. 11, when the heights of the tops of the color filters of a plurality of colors are equalized, the film thickness of the color filters of the second and subsequent colors is It is possible to adjust the thickness of the transparent resin layer 30 as thick as possible. Therefore, even if a photocurable resin is used for the color filters of the second and subsequent colors, there is an advantage that the adjustment range of the pigment concentration can be expanded by the film thickness.
　上記工程以降の工程、すなわち隔壁形成工程（第２の工程）、エッチングマスクパターン除去工程及び第２以降の色フィルターのパターンの形成工程について（第３の工程）は、前述した第１の実施形態で説明したこれらの工程と同様である。
　以上の工程により、本実施形態の固体撮像素子２が完成する。 The steps after the above steps, that is, the partition forming step (second step), the etching mask pattern removing step and the second and subsequent color filter pattern forming steps (third step) are the same as in the first embodiment described above. Are the same as those described in the above.
The solid-state imaging device 2 of the present embodiment is completed by the above steps.
　第２の実施形態に係る発明は、第１の実施形態に記載した各効果に加えて、さらに以下の効果を有する。透明導電層１２と第１の色の色フィルター１４との間に透明樹脂層３０があるため、残渣として残りやすい色フィルターの下層にドライエッチングの化学反応で容易にエッチングされる透明樹脂層３０があるので、第１の色の色フィルター１４のドライエッチング残渣が発生し難くエッチングが可能となる。 The invention according to the second embodiment has the following effects in addition to the effects described in the first embodiment. Since the transparent resin layer 30 is present between the transparent conductive layer 12 and the color filter 14 of the first color, the transparent resin layer 30 which is easily etched by a chemical reaction of dry etching is under the color filter which easily remains as a residue. Because of the presence, dry etching residue of the color filter 14 of the first color does not easily occur, and etching becomes possible.
　「第３の実施形態」
　以下、図１５から図１８を参照して、本発明の第３の実施形態に係る固体撮像素子及び固体撮像素子の製造方法について説明する。 "3rd Embodiment"
Hereinafter, with reference to FIGS. 15 to 18, a solid-state imaging device and a method of manufacturing the solid-state imaging device according to the third embodiment of the present invention will be described.
　＜固体撮像素子の構成＞
　本実施形態に係る固体撮像素子３は、図１５に示す半導体基板１０と透明導電層１２の間に透明樹脂層３０が形成されている点に特徴を有している。このため、半導体基板１０を平坦化した上で、透明導電層１２が形成でき、半導体基板１０と透明導電層１２が直接接続していない為、ドライエッチングによるプラズマダメージが、透明導電層１２から半導体基板１０に伝わりにくく、プラズマダメージの低減により効果がある利点がある。 <Configuration of solid-state imaging device>
The solid-state imaging device 3 according to the present embodiment is characterized in that a transparent resin layer 30 is formed between the semiconductor substrate 10 and the transparent conductive layer 12 shown in FIG. For this reason, after the semiconductor substrate 10 is planarized, the transparent conductive layer 12 can be formed, and since the semiconductor substrate 10 and the transparent conductive layer 12 are not directly connected, plasma damage due to dry etching occurs from the transparent conductive layer 12 to the semiconductor It is hard to be transmitted to the substrate 10, and there is an advantage that the reduction of plasma damage is effective.
　本実施形態に係る固体撮像素子の構造は、第１の実施形態と第１の色の色フィルター１４の形成工程は同様であり、透明樹脂層３０は第２の実施形態と同様である。ただし、透明樹脂層３０の形成工程が、半導体基板１０と透明導電層１２の間にある点が異なる。このため、透明樹脂層の形成工程について示す。 The structure of the solid-state imaging device according to the present embodiment is the same as the first embodiment in the process of forming the color filter 14 of the first color, and the transparent resin layer 30 is the same as that of the second embodiment. However, the difference is that the step of forming the transparent resin layer 30 is between the semiconductor substrate 10 and the transparent conductive layer 12. For this reason, the process of forming the transparent resin layer is described.
　＜固体撮像素子の製造方法＞
　次に、図１６から図１８を参照して、本実施形態の固体撮像素子３の製造方法について説明する。 <Method of manufacturing solid-state imaging device>
Next, a method of manufacturing the solid-state imaging device 3 according to the present embodiment will be described with reference to FIGS.
　図１６（ａ）に示すように、半導体基板１０上に透明樹脂材料を塗布、加熱して透明樹脂層３０を形成する。透明樹脂層３０の材料は第２の実施形態で説明した材料である。
　次に、図１６（ｂ）に示すように、透明樹脂層３０上に透明導電層１２を形成する。
次に、図１６（ｃ）に示すように透明導電層１２上に第１の色の色フィルター層１４ａを塗布により形成する。第１の色の色フィルター層１４ａは、最終的に形成される第１の色の色フィルター１４と同じか僅かに厚い膜厚を有するが、図１６及び後述する図１７では説明の便宜上、第１の色の色フィルター１４（図１８参照）よりも膜厚が薄い状態で図示されている。
　次に、図１６（ｄ）に示すように、第１の色の色フィルター層１４ａの全面を加熱によって熱硬化する。 As shown in FIG. 16A, a transparent resin material is applied on the semiconductor substrate 10 and heated to form a transparent resin layer 30. The material of the transparent resin layer 30 is the material described in the second embodiment.
Next, as shown in FIG. 16 (b), the transparent conductive layer 12 is formed on the transparent resin layer 30.
Next, as shown in FIG. 16C, the color filter layer 14a of the first color is formed on the transparent conductive layer 12 by coating. The color filter layer 14a of the first color has the same or slightly thicker film thickness as the color filter 14 of the first color to be finally formed, but in FIG. 16 and FIG. The film thickness is shown to be thinner than the color filter 14 of one color (see FIG. 18).
Next, as shown in FIG. 16D, the entire surface of the first color filter layer 14a is thermally cured by heating.
　次に、図１６（ｅ）に示すように、第１の色の色フィルター層１４ａ上に感光性樹脂材料を塗布して乾燥し、感光性樹脂材料層を形成し、エッチングマスク２０を形成する。 Next, as shown in FIG. 16E, a photosensitive resin material is applied on the color filter layer 14a of the first color and dried to form a photosensitive resin material layer, and an etching mask 20 is formed. .
　次に、図１７（ａ）に示すように、フォトマスク（図示せず）を用いて、第２及び第３の色の色フィルター形成箇所が開口するように、エッチングマスク２０を露光し、現像することで、図１７（ｂ）に示すように、開口部２０ｂを有するエッチングマスクパターン２０ａを形成する。 Next, as shown in FIG. 17A, using a photomask (not shown), the etching mask 20 is exposed so as to open the portions where the color filters of the second and third colors are formed, and then developed. By doing this, as shown in FIG. 17B, an etching mask pattern 20a having an opening 20b is formed.
　図１８（ａ）に示すように、開口部２０ｂに露出する第１の色の色フィルター層１４ａをドライエッチングによりエッチングし、次に、図１８（ｂ）に示すように、エッチングマスクパターン２０ａを除去する。図１８に示す工程及びそれ以降の工程は、前述した第１の実施形態で説明した工程と同様である。
　以上の工程により、本実施形態の固体撮像素子３が完成する。 As shown in FIG. 18A, the first color filter layer 14a exposed in the opening 20b is etched by dry etching, and then, as shown in FIG. 18B, the etching mask pattern 20a is formed. Remove. The steps shown in FIG. 18 and the steps thereafter are the same as the steps described in the first embodiment described above.
The solid-state imaging device 3 of the present embodiment is completed by the above steps.
　第３の実施形態に係る発明は、第１の実施形態に記載した各効果に加えて、さらに以下の効果を有する。透明導電層１２と第１の色の色フィルター１４との間に透明樹脂層３０があるため、残渣として残りやすい色フィルターの下層にドライエッチングの化学反応で容易にエッチングされる透明樹脂層３０があるので、色フィルターのドライエッチング残渣が発生し難くエッチングが可能となる。 The invention according to the third embodiment has the following effects in addition to the effects described in the first embodiment. Since the transparent resin layer 30 is present between the transparent conductive layer 12 and the color filter 14 of the first color, the transparent resin layer 30 which is easily etched by a chemical reaction of dry etching is under the color filter which easily remains as a residue. Since it is present, dry etching residue of the color filter is unlikely to occur and etching becomes possible.
　以下、本発明の固体撮像素子及び従来法による固体撮像素子について、実施例により具体的に説明する。 Hereinafter, the solid-state imaging device of the present invention and the solid-state imaging device according to the conventional method will be specifically described by way of examples.
＜実施例１＞
　二次元的に配置された光電変換素子を備える半導体基板上に、透明導電層としてＩＴＯ膜をマグネトロンスパッタリング法を用いて、５０ｎｍの膜厚で成膜した。成膜温度は、加工を容易にする為、非結晶膜になるように常温付近で形成した。次に半導体基板の電極部分を開口するために、シュウ酸が５％程度含有しているエッチング液を用いて、ウェットエッチングを実施した。ウェットエッチング時は、ポジ型レジスト（ＯＦＰＲ－８００：東京応化工業株式会社製）を７５０ｒｐｍの回転数でスピンコートした後、９０℃で１分間プリベークを行った。これにより、エッチングマスクとなるポジ型レジストを膜厚２．０μｍで塗布したサンプルを作製した。 Example 1
An ITO film was formed as a transparent conductive layer to a film thickness of 50 nm on the semiconductor substrate provided with the two-dimensionally arranged photoelectric conversion element using a magnetron sputtering method. The film formation temperature was formed near normal temperature so as to be an amorphous film in order to facilitate processing. Next, in order to open the electrode portion of the semiconductor substrate, wet etching was performed using an etching solution containing about 5% of oxalic acid. At the time of wet etching, a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation number of 750 rpm and then prebaked at 90 ° C. for 1 minute. As a result, a sample in which a positive resist serving as an etching mask was applied with a film thickness of 2.0 μm was produced.
　このサンプルに対して、フォトマスクを介して露光するフォトリゾグラフィーを行った。露光装置は光源にｉ線の波長を用いた露光装置を用いた。ポジ型レジストは、紫外線照射により、化学反応を起こして現像液に溶解するようになった。
　次に、２．３８質量％のＴＭＡＨ（テトラメチルアンモニウムハイドライド）を現像液として用いて現像工程を行い、半導体基板の電極部分に開口部を有するエッチングマスクを形成した。次にエッチング液に３分浸漬させてウェットエッチングを行い、純水で洗浄して、電極部分を開口させた。次に、エッチングマスクとして用いたポジ型レジストの除去を行った。この際用いた方法は溶剤を用いた方法であり、剥離液１０４（東京応化工業株式会社製）を用いてスプレー洗浄装置でポジ型レジストの除去を行った。次にホットプレートにて２５０度で３０分間加熱処理を行い、ＩＴＯの膜を結晶化させた。この際、シート抵抗は５０Ω／ｓｑ．以下であり、可視光の透過率が８９％であった。 The sample was subjected to photolithography which was exposed through a photomask. The exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source. The positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
Next, a development step was performed using 2.38% by mass of TMAH (tetramethylammonium hydride) as a developing solution to form an etching mask having an opening in the electrode portion of the semiconductor substrate. Next, it was immersed in an etching solution for 3 minutes to perform wet etching, and it was washed with pure water to open the electrode portion. Next, the positive resist used as the etching mask was removed. The method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus. Next, heat treatment was performed on a hot plate at 250 ° C. for 30 minutes to crystallize the ITO film. At this time, the sheet resistance is 50 Ω / sq. It is below and the transmittance | permeability of visible light was 89%.
　次に、１色目であるグリーンの顔料を含む第１の色の色フィルター用材料として、感光性硬化樹脂と熱硬化性樹脂を含ませたグリーン顔料分散液を１０００ｒｐｍの回転数でスピンコートした。この１色目の色フィルター用材料のグリーンの顔料には、カラーインデックスにてＣ．Ｉ．ＰＧ５８を用いており、その顔料濃度は７０質量％、膜厚は５００ｎｍであった。 Next, a green pigment dispersion containing a photosensitive curable resin and a thermosetting resin was spin-coated at a rotational speed of 1000 rpm as a first color filter material containing a green pigment, which is the first color. The green pigment of the first color material for the color filter has C.I. I. PG 58 was used, the pigment concentration was 70% by mass, and the film thickness was 500 nm.
　次に、グリーンフィルター用材料の硬化を実施するため、ｉ線の露光装置であるステッパーを用いて全面の露光を行い、感光性成分の硬化を実施した。この感光性成分の硬化により、グリーンフィルターの表面の硬化を実施した。続いて、ホットプレートで２３０℃で６分間ベークを行い、グリーンフィルターの熱硬化を行った。 Next, in order to cure the green filter material, the entire surface was exposed using a stepper which is an i-line exposure device to cure the photosensitive component. The surface of the green filter was cured by curing the photosensitive component. Subsequently, baking was performed at 230 ° C. for 6 minutes on a hot plate to thermally cure the green filter.
　次に、ポジ型レジスト（ＯＦＰＲ－８００：東京応化工業株式会社製）を、スピンコーターを用いて１０００ｒｐｍの回転数でスピンコートした後、９０℃で１分間プリベークを行った。これにより、エッチングマスクとなるポジ型レジストを膜厚１．５μｍで塗布したサンプルを作製した。 Next, a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin coated using a spin coater at a rotation number of 1000 rpm, and then prebaked at 90 ° C. for 1 minute. Thus, a sample in which a positive resist serving as an etching mask was applied with a film thickness of 1.5 μm was produced.
　このサンプルに対して、フォトマスクを介して露光するフォトリゾグラフィーを行った。露光装置は光源にｉ線の波長を用いた露光装置を用いた。ポジ型レジストは、紫外線照射により、化学反応を起こして現像液に溶解するようになった。 The sample was subjected to photolithography which was exposed through a photomask. The exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source. The positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
　次に、２．３８質量％のＴＭＡＨ（テトラメチルアンモニウムハイドライド）を現像液として用いて現像工程を行い、第２及び第３の色の色フィルターを形成する箇所に開口部を有するエッチングマスクを形成した。ポジ型レジストを用いる際には、現像後脱水ベークを行い、ポジ型レジストの硬化を行うことが多い。しかしながら、今回はドライエッチング後のエッチングマスクの除去を容易にするため、ベーク工程を実施しなかった。そのため、レジストが硬化せず選択比の向上が見込めないため、レジストの膜厚をグリーンフィルターである第１の色の色フィルターの膜厚の２倍以上である、１．５μｍの膜厚で形成した。この際の開口部パターンは、１．１μｍ×１．１μｍで形成した。
　これにより、ポジ型レジストを用いたエッチングマスクパターンを形成した。 Next, a development step is performed using 2.38% by mass of TMAH (tetramethyl ammonium hydride) as a developer to form an etching mask having an opening at a position where a color filter of the second and third colors is formed. did. When using a positive resist, dehydration baking is often performed after development to cure the positive resist. However, this time, in order to facilitate removal of the etching mask after dry etching, the bake step was not performed. Therefore, since the resist is not cured and improvement in selectivity can not be expected, the film thickness of the resist is formed to a film thickness of 1.5 μm which is twice or more of the film thickness of the first color filter which is a green filter. did. The opening pattern at this time was formed to be 1.1 μm × 1.1 μm.
Thus, an etching mask pattern using a positive resist was formed.
　次に、形成したエッチングマスクパターンを用いて、グリーンフィルター層のドライエッチングを行った。この際、用いたドライエッチング装置は、ＩＣＰ方式のドライエッチング装置を用いた。また、下地の半導体基板に影響を与えないように、途中でドライエッチング条件の変更を行い、ドライエッチングを多段階で実施した。 Next, dry etching of the green filter layer was performed using the formed etching mask pattern. At this time, the dry etching apparatus used was an ICP dry etching apparatus. In addition, dry etching conditions were changed on the way so as not to affect the underlying semiconductor substrate, and dry etching was performed in multiple steps.
　始めのガス種は、ＣＦ４、Ｏ２、Ａｒガスの三種を混合してエッチングを実施した。ＣＦ４、Ｏ２のガス流量を各５ｍｌ／ｍｉｎ、Ａｒのガス流量を２００ｍｌ／ｍｉｎとした。すなわち、全ガス流量中、Ａｒのガス流量が９５．２％であった。また、この際のドライエッチング条件はチャンバー内の圧力を１Ｐａの圧力とし、ＲＦパワーを５００Ｗ、コイルパワーを１０００Ｗとして設定した。この条件を用いて、グリーンフィルター層の膜厚５００ｎｍの内、３５０ｎｍをドライエッチングした段階で、次のドライエッチング条件に変更した。 The first gas species were etched by mixing three kinds of CF 4 , O 2 and Ar gas. The gas flow rates of CF 4 and O 2 were 5 ml / min, and the gas flow rate of Ar was 200 ml / min. That is, the gas flow rate of Ar was 95.2% in the total gas flow rate. Moreover, the dry etching conditions in this case set the pressure in a chamber to a pressure of 1 Pa, RF power was set to 500 W, and coil power was set to 1000 W. The dry etching conditions were changed to the following dry etching conditions when dry etching was performed on 350 nm of the film thickness of 500 nm of the green filter layer using this condition.
　次のガス種は、ＣＦ４ガスとＯ２ガスを混ぜた混合ガスを用い、エッチング条件はＣＦ４のガス流量を１５０ｍｌ／ｍｉｎ、Ｏ２のガス流量を１５０ｍｌ／ｍｉｎで５０対５０の比率で混合し、チャンバー内圧力を２Ｐａ、ＲＦパワーを５００Ｗ、コイルパワーを１０００Ｗの条件とした。この条件を用いて、グリーンフィルター層の残留分のドライエッチングを行った。透明導電層として形成したＩＴＯ膜はＣＦ４ガス及びＯ２ガスのエッチングレートがグリーンのエッチングレートに対して２０倍以上遅く、ほぼエッチングされない構成の為、この際、グリーンの残渣が残らないように、残留しているグリーンフィルターの膜厚１５０ｎｍの３倍の４５０ｎｍがエッチングされる時間設定でオーバーエッチングを実施した。この工程により、グリーンフィルターは残渣が残らず、ＩＴＯ膜は膜厚５０ｎｍの内、５ｎｍエッチングされる状況であった。 The next gas species is a mixed gas of CF 4 gas and O 2 gas, and the etching conditions are 50 ml / min at a gas flow rate of 150 ml / min for CF 4 and 150 ml / min for an O 2 gas flow rate. The mixture was mixed, the pressure in the chamber was 2 Pa, the RF power was 500 W, and the coil power was 1000 W. Dry etching of the remaining portion of the green filter layer was performed using this condition. The ITO film formed as a transparent conductive layer has a configuration in which the etching rate of CF 4 gas and O 2 gas is 20 times or more slower than the etching rate of green and almost no etching occurs, so no green residue is left at this time. The over-etching was performed with a time setting in which three times 450 nm of the remaining green filter film thickness of 150 nm was etched. According to this process, the green filter did not leave any residue, and the ITO film was etched 5 nm out of the film thickness of 50 nm.
　また、上記ドライエッチングの際に、グリーンフィルターパターンの側壁にグリーンフィルター用材料及び透明導電層であるＩＴＯ材料と、ドライエッチングガスとの反応生成物を含んだ隔壁を形成した。この隔壁はドライエッチング条件の時間調整で、隔壁の寸法（横幅）を制御可能である。
上記ドライエッチング条件ではグリーンフィルターを５００ｎｍと透明導電層を５ｎｍほどドライエッチングしたが、それらの反応生成物による隔壁の寸法は２５ｎｍであった。 Further, during the above-mentioned dry etching, partition walls were formed on the side walls of the green filter pattern, which contained a reaction product of a green filter material and an ITO material which is a transparent conductive layer, and a dry etching gas. This partition can control the dimension (width) of the partition by adjusting the time of dry etching conditions.
Under the above-mentioned dry etching conditions, the green filter was dry etched to 500 nm and the transparent conductive layer to 5 nm, but the dimensions of the partition walls due to their reaction products were 25 nm.
　次に、エッチングマスクとして用いたポジ型レジストの除去を行った。この際用いた方法は溶剤を用いた方法であり、剥離液１０４（東京応化工業株式会社製）を用いてスプレー洗浄装置でポジ型レジストの除去を行った。 Next, the positive resist used as the etching mask was removed. The method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus.
（第２の色の色フィルターの作製）
　次に第２の色の色フィルター形成工程を行った。第２の色の色フィルターを設けるべく顔料分散ブルーを含有している感光性を有したブルーレジストを半導体基板全面に塗布した。この時、ブルーレジスト塗布前に、密着性を向上させるためＨＭＤＳ処理をしても良い。
　次に、フォトリソグラフィによりブルーレジストを選択的に露光して、現像を行い、ブルーフィルターパターンを形成した。このとき、ブルーレジストに用いた顔料は、それぞれカラーインデックスにてＣ．Ｉ．ＰＢ１５６、Ｃ．Ｉ．ＰＶ２３であり、顔料濃度は５０質量％であった。また、ブルーフィルターの膜厚は５５０ｎｍであった。また、ブルーレジストの主成分である樹脂としては、感光性を持たせたアクリル系の樹脂を用いた。 (Preparation of second color filter)
Next, a color filter formation step of the second color was performed. A photosensitive blue resist containing pigment dispersion blue was applied over the entire surface of the semiconductor substrate to provide a second color filter. At this time, HMDS treatment may be performed to improve the adhesion before applying the blue resist.
Next, the blue resist was selectively exposed by photolithography and development was performed to form a blue filter pattern. At this time, the pigment used for the blue resist has C.I. I. PB 156, C.I. I. It was PV23, and the pigment concentration was 50% by mass. Moreover, the film thickness of the blue filter was 550 nm. Further, as a resin which is a main component of the blue resist, an acrylic resin having photosensitivity was used.
　次に、ブルーフィルター層を強固に硬化させるため、ホットプレートで２３０℃で６分間ベークを行い硬化を行った。この加熱工程を経た後は、第３の色の色フィルター形成工程等の工程を経ても、剥がれや、パターンの崩れ等が確認されなかった。ブルーフィルターは周囲を矩形性の良いグリーンフィルター及び隔壁に覆われており、矩形性良く形成されるため、底面及び周囲との間で密着性良く硬化することが確認された。 Next, in order to harden the blue filter layer firmly, baking was performed at 230 ° C. for 6 minutes on a hot plate for hardening. After passing through the heating step, no peeling or pattern collapse was found even after passing through the step of forming the third color filter and the like. The blue filter is covered with a green filter and partition walls with good rectangularity, and is formed with good rectangularity, so it was confirmed that the blue filter cures with good adhesion between the bottom and the periphery.
（第３の色の色フィルターの作製）
　次に第３の色の色フィルター形成工程を行った。第３の色の色フィルターを設けるべく顔料分散レッドを含有している感光性を有したレッドレジストを半導体基板全面に塗布した。
　次に、フォトリソグラフィによりレッドレジストを選択的に露光して、現像を行い、レッドフィルターパターンを形成した。このとき、レッドレジストに用いた顔料は、それぞれカラーインデックスにてＣ．Ｉ．ＰＲ２５４、Ｃ．Ｉ．ＰＹ１３９であり、顔料濃度は６０質量％であった。また、レッドフィルターの膜厚は５５０ｎｍであった。 (Preparation of third color filter)
Next, a color filter formation step of the third color was performed. A photosensitive red resist containing pigment dispersed red was applied over the entire surface of the semiconductor substrate to provide a third color filter.
Next, the red resist was selectively exposed by photolithography and developed to form a red filter pattern. At this time, the pigment used for the red resist has C.I. I. PR 254, C.I. I. PY 139, and the pigment concentration was 60% by mass. Moreover, the film thickness of the red filter was 550 nm.
　次に、レッドフィルター層を強固に硬化させるため、ホットプレートで２３０℃で６分間ベークを行い硬化を行った。この際、第３の色の色フィルターは周囲を矩形性の良いグリーンフィルター及び隔壁に覆われており、矩形性良く形成されるため、底面及び周囲との間で、密着性良く硬化することが確認された。 Next, in order to harden the red filter layer firmly, baking was performed at 230 ° C. for 6 minutes on a hot plate for hardening. At this time, the color filter of the third color is covered with a green filter and a partition having good rectangularity, and is formed with good rectangularity, so that it can be cured with good adhesion between the bottom and the periphery. confirmed.
　上記の工程により、グリーンからなる第１の色の色フィルターの膜厚Ａ（５００ｎｍ）と、その下層の透明導電層Ｂ（５０ｎｍ）、ブルーとレッドからなる第２及び第３の色の色フィルターである膜厚Ｃ（５５０ｎｍ）は、本発明に基づく膜厚となっている。また、本実施例では第２及び第３の色の色フィルター層の下層に透明導電層が膜厚４５ｎｍで構成されている。 According to the above steps, the film thickness A (500 nm) of the green first color filter, the second transparent conductive layer B (50 nm) therebelow, and the second and third color filters of blue and red The film thickness C (550 nm) is the film thickness based on the present invention. Further, in the present embodiment, a transparent conductive layer is formed to a film thickness of 45 nm below the color filter layers of the second and third colors.
　次に、上記の工程で形成した色フィルター上にアクリル樹脂を含む塗布液を回転数１０００ｒｐｍでスピンコートし、ホットプレートにて２００℃で３０分間の加熱処理を施して、樹脂を硬化し、平坦化層を形成した。 Next, a coating solution containing an acrylic resin is spin-coated at a rotational speed of 1000 rpm on the color filter formed in the above process, and heat treated at 200 ° C. for 30 minutes on a hot plate to cure the resin and flat. Layer was formed.
　最後に、平坦化層上に、上述した公知の技術であるエッチバックによる転写方法を用いてレンズトップからレンズボトムまでの高さを５００ｎｍとなるマイクロレンズを形成し、実施例１の固体撮像素子を完成した。 Finally, on the planarizing layer, a microlens having a height from the lens top to the lens bottom of 500 nm is formed using the transfer method by etch back which is the above-mentioned known technique, and the solid-state imaging device of Example 1 Completed.
　以上のようにして得た固体撮像素子は、第１の色の色フィルターの下部に透明導電層が５０ｎｍ形成され、第２、第３の色の色フィルターの下部に透明導電層が４５ｎｍ形成されている。また、１色目であるグリーンフィルターは熱硬化性樹脂と少量の感光性硬化樹脂を用いているため固形分中の顔料の濃度を上げることが可能で、所望の分光特性が得られる膜厚が従来の感光性レジストを用いてパターニングする時よりも、色フィルターを薄膜化できた。また、第２および第３の色の色フィルターである、ブルー及びレッドは感光性樹脂を用いているが、従来工程と異なり第１の色の色フィルターは矩形性良くパターンが形成されてガイドパターンとなっている部分に穴埋めを行うだけである。そのため、ブルー及びレッドは感光性樹脂の割合を従来よりも少なくできる為、顔料濃度を上げて、膜厚が薄くとも求める分光特性を形成しやすくなる利点がある。これらの効果により、グリーン、ブルー、レッドの各色は従来工程より薄膜化が可能で、マイクロレンズから半導体基板までの距離が小さくなり、良好な感度を有するものとなった。
　また、透明導電層の可視光の透過率は８９％で、形成した隔壁の寸法が２５ｎｍであるため、本発明の規定を満足している。 In the solid-state imaging device obtained as described above, 50 nm of the transparent conductive layer is formed under the first color filter, and 45 nm of the transparent conductive layer is formed under the second and third color filters. ing. In addition, since the green filter, which is the first color, uses a thermosetting resin and a small amount of a photosensitive curable resin, the concentration of the pigment in the solid content can be increased, and the film thickness at which desired spectral characteristics can be obtained The color filter can be made thinner than when patterning using a photosensitive resist of In addition, blue and red, which are color filters for the second and third colors, use photosensitive resins, but unlike the conventional process, the color filter for the first color has a rectangular pattern with good rectangularity and is a guide pattern Only fill in the part where Therefore, since blue and red can reduce the proportion of the photosensitive resin as compared with the prior art, there is an advantage that it is easy to form the spectral characteristics to be obtained even if the film thickness is thin by increasing the pigment concentration. Due to these effects, the respective colors of green, blue and red can be made thinner than in the conventional process, the distance from the microlens to the semiconductor substrate becomes smaller, and the film has excellent sensitivity.
Further, the visible light transmittance of the transparent conductive layer is 89%, and the dimension of the formed partition is 25 nm, which satisfies the definition of the present invention.
　また、エッチング時に半導体基板の上に透明導電層があり、エッチング時のエッチングストッパーの役割を果たし、導電性があるため、グリーンのドライエッチング時のプラズマダメージを逃す効果があり、半導体基板に形成した光電変換素子に対して、ドライエッチングの影響は観測されなかった。 In addition, there is a transparent conductive layer on the semiconductor substrate at the time of etching, plays a role of an etching stopper at the time of etching, and has conductivity, so it has an effect of escaping plasma damage at the time of dry etching of green. No influence of dry etching was observed on the photoelectric conversion element.
　更に、グリーンフィルターからなる第１の色の色フィルターの色フィルター用材料は、熱硬化で内部を固めており、さらに少量の感光性樹脂を用いて露光で表面を固めるため、溶剤耐性が向上した。顔料含有率の高いグリーンフィルター用材料を用いた場合、溶剤や他の色フィルター材料と反応して分光特性が変化することがある。そのため、上記の熱硬化及び光硬化を併用することで、溶剤耐性を向上することが可能となり、分光特性の変化を抑制する効果がある。 Furthermore, the material for the color filter of the first color filter comprising green filters hardens the inside by heat curing, and hardens the surface by exposure using a small amount of photosensitive resin, thus improving the solvent resistance. . When a green filter material having a high pigment content is used, it may react with a solvent or another color filter material to change its spectral characteristics. Therefore, it becomes possible to improve solvent tolerance by using the above-mentioned thermosetting and photocuring together, and there is an effect which controls change of spectral characteristics.
　本実施例では、第１の色の色フィルターであるグリーンフィルターの硬化性、溶剤耐性を向上させるため、熱硬化樹脂と光硬化性樹脂を併用する材料を用いたが、求める分光特性によっては、顔料濃度や、経時特性などを重視して、熱硬化性樹脂のみ又は、光硬化性樹脂のみで材料を形成しても問題ない。
　本実施例は、ブルー及びレッドで求める分光特性を得るために、グリーンよりも膜厚が厚く構成している。その為、図１（ａ）に示すようなグリーン、ブルー、レッドの高さがそろっている構造ではなく、ブルーとレッドが５０ｎｍ程度突き出す構造となった。 In this example, in order to improve the curability and solvent resistance of the green filter which is the color filter of the first color, a material in which the thermosetting resin and the photocurable resin are used in combination is used. There is no problem if the material is formed of only the thermosetting resin or only the photocurable resin, with emphasis on pigment concentration, time-dependent characteristics and the like.
In this embodiment, the film thickness is thicker than that of green in order to obtain the spectral characteristics required for blue and red. Therefore, it does not have a structure in which the heights of green, blue and red are aligned as shown in FIG. 1 (a), but the structure in which blue and red project about 50 nm.
＜実施例２＞
　実施例２では、第２の実施形態で説明した構成の固体撮像素子に対応する実施例である。
　実施例２の固体撮像素子は、透明導電層の上に透明樹脂層が形成されている構成である。透明樹脂層があることで、色フィルターの密着性が改善し、第１の色の色フィルターをエッチングする際に残渣が発生しにくくなる効果がある。 Example 2
Example 2 is an example corresponding to the solid-state imaging device having the configuration described in the second embodiment.
The solid-state imaging device of Example 2 has a configuration in which a transparent resin layer is formed on a transparent conductive layer. By the presence of the transparent resin layer, the adhesion of the color filter is improved, and when etching the color filter of the first color, there is an effect that it is difficult to generate a residue.
　二次元的に配置された光電変換素子を備える半導体基板上に、透明導電層としてＩＴＯ膜をマグネトロンスパッターを用いて、３０ｎｍの膜厚で成膜した。成膜温度は、加工を容易にする為、非結晶膜になるように常温付近で形成した。次に半導体基板の電極部分を開口するために、シュウ酸が５％程度含有しているエッチング液を用いて、ウェットエッチングを実施した。ウェットエッチング時は、ポジ型レジスト（ＯＦＰＲ－８００：東京応化工業株式会社製）を７５０ｒｐｍの回転数でスピンコートした後、９０℃で１分間プリベークを行った。これにより、エッチングマスクとなるポジ型レジストを膜厚２．０μｍで塗布したサンプルを作製した。 An ITO film was formed as a transparent conductive layer to a film thickness of 30 nm using magnetron sputtering on a semiconductor substrate provided with photoelectric conversion elements arranged two-dimensionally. The film formation temperature was formed near normal temperature so as to be an amorphous film in order to facilitate processing. Next, in order to open the electrode portion of the semiconductor substrate, wet etching was performed using an etching solution containing about 5% of oxalic acid. At the time of wet etching, a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation number of 750 rpm and then prebaked at 90 ° C. for 1 minute. As a result, a sample in which a positive resist serving as an etching mask was applied with a film thickness of 2.0 μm was produced.
　このサンプルに対して、フォトマスクを介して露光するフォトリゾグラフィーを行った。露光装置は光源にｉ線の波長を用いた露光装置を用いた。ポジ型レジストは、紫外線照射により、化学反応を起こして現像液に溶解するようになった。
　次に、２．３８質量％のＴＭＡＨ（テトラメチルアンモニウムハイドライド）を現像液として用いて現像工程を行い、半導体基板の電極部分に開口部を有するエッチングマスクを形成した。次にエッチング液に３分浸漬させてウェットエッチングを行い、純水で洗浄して、電極部分を開口させた。次に、エッチングマスクとして用いたポジ型レジストの除去を行った。この際用いた方法は溶剤を用いた方法であり、剥離液１０４（東京応化工業株式会社製）を用いてスプレー洗浄装置でポジ型レジストの除去を行った。次にホットプレートにて２５０度で３０分間加熱処理を行い、ＩＴＯの膜を結晶化させた。この際、シート抵抗は５０Ω／ｓｑ．以下であり、可視光の透過率が９５％であった。 The sample was subjected to photolithography which was exposed through a photomask. The exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source. The positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
Next, a development step was performed using 2.38% by mass of TMAH (tetramethylammonium hydride) as a developing solution to form an etching mask having an opening in the electrode portion of the semiconductor substrate. Next, it was immersed in an etching solution for 3 minutes to perform wet etching, and it was washed with pure water to open the electrode portion. Next, the positive resist used as the etching mask was removed. The method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus. Next, heat treatment was performed on a hot plate at 250 ° C. for 30 minutes to crystallize the ITO film. At this time, the sheet resistance is 50 Ω / sq. It is below and the transmittance | permeability of visible light was 95%.
（透明樹脂層の形成）
　半導体基板上に形成された透明導電層であるＩＴＯ上に、アクリル樹脂を含む塗布液を回転数３０００ｒｐｍでスピンコートし、ホットプレートにて２３０℃で６分間の加熱処理を施して、樹脂を硬化し、透明樹脂層を形成した。この際の透明樹脂層の膜厚は３０ｎｍで可視光の透過率は９５％であった。 (Formation of transparent resin layer)
A coating solution containing an acrylic resin is spin coated at 3000 rpm on ITO, which is a transparent conductive layer formed on a semiconductor substrate, and heat treated at 230 ° C. for 6 minutes on a hot plate to cure the resin. And a transparent resin layer was formed. The thickness of the transparent resin layer at this time was 30 nm, and the visible light transmittance was 95%.
（第１の色の色フィルターの形成）
　次に、第１の色の色フィルター（グリーンフィルター）の色フィルター用材料として、感光性硬化樹脂と熱硬化性樹脂を含ませたグリーン顔料分散液を１０００ｒｐｍの回転数でスピンコートした。この１色目の色フィルター用材料のグリーンの顔料には、カラーインデックスにてＣ．Ｉ．ＰＧ５８を用いており、その顔料濃度は７０質量％、膜厚は５００ｎｍであった。 (Formation of the color filter of the first color)
Next, a green pigment dispersion liquid containing a photosensitive curable resin and a thermosetting resin was spin-coated at a rotational speed of 1000 rpm as a color filter material of a first color filter (green filter). The green pigment of the first color material for the color filter has C.I. I. PG 58 was used, the pigment concentration was 70% by mass, and the film thickness was 500 nm.
　次に、グリーンフィルター用材料の硬化を実施するため、ｉ線の露光装置であるステッパーを用いて全面の露光を行い、感光性成分の硬化を実施した。この感光性成分の硬化により、グリーンフィルターの表面の硬化を実施した。続いて、ホットプレートで２３０℃で６分間ベークを行い、グリーンフィルターの熱硬化を行った。 Next, in order to cure the green filter material, the entire surface was exposed using a stepper which is an i-line exposure device to cure the photosensitive component. The surface of the green filter was cured by curing the photosensitive component. Subsequently, baking was performed at 230 ° C. for 6 minutes on a hot plate to thermally cure the green filter.
（第１の色の色フィルターの形成）
　実施例１に示す方法にてエッチングマスクを形成したあとで、グリーンフィルター層及び透明樹脂層をエッチングした。エッチング条件は実施例１と同様の条件を用いているが、グリーンフィルターの下層に透明樹脂層があるため、グリーンフィルターの残渣が残留しにくい。その為、実施例１では、グリーンフィルターの残留分１５０ｎｍの３倍の４５０ｎｍをエッチングする時間調整を行うオーバーエッチングを行ったが、今回は２倍のグリーンフィルター３００ｎｍをエッチングする時間でオーバーエッチングを実施した。その結果、第２及び第３の色の色フィルター形成箇所は、グリーンフィルター及び透明樹脂層は全てエッチングされ、透明導電層は膜厚３０ｎｍからほぼ変化が無かった。その後、実施例１に示す方法にてエッチングマスクとして用いたポジ型レジストの除去を行った。 (Formation of the color filter of the first color)
After the etching mask was formed by the method described in Example 1, the green filter layer and the transparent resin layer were etched. The etching conditions are the same as in Example 1. However, since the transparent resin layer is present in the lower layer of the green filter, the residue of the green filter is unlikely to remain. Therefore, in Example 1, the over-etching was performed to adjust the time to etch 450 nm, which is three times 150 nm of the remaining portion of the green filter, but this time the over-etching is performed in the time to etch 300 nm of the green filter. did. As a result, the green filter and the transparent resin layer were all etched where the color filters of the second and third colors were formed, and the thickness of the transparent conductive layer was almost unchanged from 30 nm. Thereafter, the positive resist used as the etching mask was removed by the method described in Example 1.
　また、上記ドライエッチングの際に、グリーンフィルターパターンの側壁にグリーンフィルター用材料、透明樹脂層のアクリル樹脂の材料及び透明導電層であるＩＴＯ材料と、ドライエッチングガスとの反応生成物を含んだ隔壁を形成した。この隔壁はドライエッチング条件の時間調整で、隔壁の寸法（横幅）を制御可能である。
上記ドライエッチング条件ではグリーンフィルターを５００ｎｍと透明樹脂層を３０ｎｍほどドライエッチングしたが、それらの反応生成物による隔壁の寸法は３０ｎｍであった。 Moreover, in the case of the above-mentioned dry etching, a partition wall containing a reaction product of a dry etching gas, a material for a green filter, a material for an acrylic resin of a transparent resin layer and an ITO material which is a transparent conductive layer on side walls of a green filter pattern. Formed. This partition can control the dimension (width) of the partition by adjusting the time of dry etching conditions.
Under the above-mentioned dry etching conditions, the green filter was dry etched to 500 nm and the transparent resin layer to 30 nm, but the dimensions of the partition walls due to their reaction products were 30 nm.
（第２、第３の色の色フィルター等の作製）
　実施例２では、この後、実施例１と同様の手法で第２、第３の色の色フィルター、上層の平坦化層及びマイクロレンズを形成し、実施例２の固体撮像素子を形成した。 (Preparation of second and third color filters etc.)
In Example 2, thereafter, the color filters for the second and third colors, the flattening layer on the upper layer, and the microlenses were formed by the same method as in Example 1, and the solid-state imaging device of Example 2 was formed.
　上記の工程により、実施例２も実施例１同様に第１の色の色フィルターであるグリーンの膜厚５００ｎｍとその下層の透明樹脂層の膜厚３０ｎｍ、またその下層の透明導電層の膜厚３０ｎｍ、第２及び第３の色の色フィルターであるブルーとレッドの膜厚５５０ｎｍ、透明樹脂層と透明導電層の可視光の透過率（９５％）、隔壁の寸法Ｅ（３０ｎｍ）は、本発明の規定を満足している。また、本実施例では第２及び第３の色の色フィルター層の下層のみ透明樹脂層が無く、透明導電層のみが構成されている。
　本実施例は、ブルー及びレッドで求める分光特性を得るために、グリーンよりも膜厚が厚く構成している。その為、図１（ｂ）に示すようにグリーン、ブルー、レッドの高さがそろっている構造ではなく、ブルーとレッドが２０ｎｍ程度突き出す構造となった。 According to the above steps, as in Example 1, Example 2 also has the film thickness of 500 nm of the green color filter of the first color and the film thickness of the transparent resin layer below it of 30 nm, and the film thickness of the transparent conductive layer below it. 30 nm, 550 nm film thickness of blue and red which are color filters of second and third colors, visible light transmittance (95%) of transparent resin layer and transparent conductive layer, dimension E (30 nm) of partition wall The requirements of the invention are satisfied. Further, in the present embodiment, only the lower layer of the second and third color filter layers has no transparent resin layer, and only the transparent conductive layer is formed.
In this embodiment, the film thickness is thicker than that of green in order to obtain the spectral characteristics required for blue and red. Therefore, as shown in FIG. 1 (b), the structure is not a structure in which the heights of green, blue and red are aligned, but a structure in which blue and red protrude by about 20 nm.
　本実施例では、実施例１に比べて透明導電層の膜厚を５０ｎｍから３０ｎｍに薄膜化している。透明樹脂層及び透明導電層の膜厚が厚くなればなるほど、色フィルターから光電変換素子までの距離が長くなり、混色などにより受光感度が低下しやすくなるためである。
　また、透明樹脂層及び、透明導電層の可視光の光透過率は１００％ではないため、厚くなると透過率が低下しやすいためである。ドライエッチングのプラズマダメージの低下及び色フィルターの残渣除去の観点からは、透明樹脂層及び透明導電層の膜厚が厚いほうが、製造工程上の条件範囲が広がるため、混色の発生や透過率の低下により受光感度が悪化しない範囲で膜厚を形成することが可能となる。 In the present embodiment, the thickness of the transparent conductive layer is reduced to 50 nm to 30 nm as compared with the first embodiment. This is because as the film thickness of the transparent resin layer and the transparent conductive layer becomes thicker, the distance from the color filter to the photoelectric conversion element becomes longer, and the light receiving sensitivity is easily lowered due to color mixing or the like.
Moreover, since the light transmittance of the visible light of the transparent resin layer and the transparent conductive layer is not 100%, the transmittance tends to decrease when the thickness is increased. From the viewpoint of reducing plasma damage in dry etching and removing residues of color filters, the thicker the film thickness of the transparent resin layer and the transparent conductive layer, the wider the range of conditions in the manufacturing process, so color mixing occurs and the transmittance decreases. Thus, the film thickness can be formed within the range in which the light receiving sensitivity does not deteriorate.
＜実施例３＞
　実施例３は、第３の実施形態で説明した構成の固体撮像素子に対応する実施例である。
　実施例３に示す固体撮像素子は、実施例１の半導体基板と透明導電層の間に透明樹脂層がある構成である。透明樹脂層があることにより、半導体基板の平坦化がより可能となるため、ＩＴＯなどの透明導電層を性能良く形成しやすくなる。また、半導体基板と透明導電層が直接接していない為、色フィルターのドライエッチング時のプラズマダメージが半導体基板に影響しにくい特徴がある。 Example 3
Example 3 is an example corresponding to the solid-state imaging device having the configuration described in the third embodiment.
The solid-state imaging device shown in Example 3 has a configuration in which a transparent resin layer is present between the semiconductor substrate of Example 1 and the transparent conductive layer. The presence of the transparent resin layer makes it possible to further planarize the semiconductor substrate, so that a transparent conductive layer such as ITO can be easily formed with good performance. In addition, since the semiconductor substrate and the transparent conductive layer are not in direct contact with each other, plasma damage during dry etching of the color filter is unlikely to affect the semiconductor substrate.
（透明樹脂層の形成）
　半導体基板上に、アクリル樹脂を含む塗布液を回転数２０００ｒｐｍでスピンコートし、ホットプレートにて２００℃で２０分間の加熱処理を施して、樹脂を硬化し、透明樹脂層を形成した。この際の透明樹脂層の膜厚は６０ｎｍで可視光の透過率は９１％であった。 (Formation of transparent resin layer)
A coating solution containing an acrylic resin is spin-coated on a semiconductor substrate at a rotational speed of 2000 rpm, and heat treatment is performed on a hot plate at 200 ° C. for 20 minutes to cure the resin to form a transparent resin layer. The transparent resin layer had a thickness of 60 nm and a visible light transmittance of 91%.
　次に透明樹脂層上に、透明導電層としてＩＴＯ膜をマグネトロンスパッターを用いて、３０ｎｍの膜厚で成膜した。成膜温度は、加工を容易にする為、非結晶膜になるように常温付近で形成した。次に半導体基板の電極部分を開口するために、シュウ酸が５％程度含有しているエッチング液を用いて、ウェットエッチングを実施した。ウェットエッチング時は、ポジ型レジスト（ＯＦＰＲ－８００：東京応化工業株式会社製）を７５０ｒｐｍの回転数でスピンコートした後、９０℃で１分間プリベークを行った。これにより、エッチングマスクとなるポジ型レジストを膜厚２．０μｍで塗布したサンプルを作製した。 Next, an ITO film was formed as a transparent conductive layer on the transparent resin layer to a film thickness of 30 nm using magnetron sputtering. The film formation temperature was formed near normal temperature so as to be an amorphous film in order to facilitate processing. Next, in order to open the electrode portion of the semiconductor substrate, wet etching was performed using an etching solution containing about 5% of oxalic acid. At the time of wet etching, a positive resist (OFPR-800: manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation number of 750 rpm and then prebaked at 90 ° C. for 1 minute. As a result, a sample in which a positive resist serving as an etching mask was applied with a film thickness of 2.0 μm was produced.
　このサンプルに対して、フォトマスクを介して露光するフォトリゾグラフィーを行った。露光装置は光源にｉ線の波長を用いた露光装置を用いた。ポジ型レジストは、紫外線照射により、化学反応を起こして現像液に溶解するようになった。
　次に、２．３８質量％のＴＭＡＨ（テトラメチルアンモニウムハイドライド）を現像液として用いて現像工程を行い、半導体基板の電極部分に開口部を有するエッチングマスクを形成した。次にエッチング液に３分浸漬させてウェットエッチングを行い、純水で洗浄して、電極部分を開口させた。次に、エッチングマスクとして用いたポジ型レジストの除去を行った。この際用いた方法は溶剤を用いた方法であり、剥離液１０４（東京応化工業株式会社製）を用いてスプレー洗浄装置でポジ型レジストの除去を行った。次にホットプレートにて２５０度で３０分間加熱処理を行い、ＩＴＯの膜を結晶化させた。この際、シート抵抗は５０Ω／ｓｑ．以下であり、可視光の透過率が９５％であった。 The sample was subjected to photolithography which was exposed through a photomask. The exposure apparatus used the exposure apparatus which used the wavelength of i line as a light source. The positive resist caused a chemical reaction by ultraviolet irradiation and became soluble in the developer.
Next, a development step was performed using 2.38% by mass of TMAH (tetramethylammonium hydride) as a developing solution to form an etching mask having an opening in the electrode portion of the semiconductor substrate. Next, it was immersed in an etching solution for 3 minutes to perform wet etching, and it was washed with pure water to open the electrode portion. Next, the positive resist used as the etching mask was removed. The method used in this case was a method using a solvent, and the positive resist was removed using a stripping solution 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spray cleaning apparatus. Next, heat treatment was performed on a hot plate at 250 ° C. for 30 minutes to crystallize the ITO film. At this time, the sheet resistance is 50 Ω / sq. It is below and the transmittance | permeability of visible light was 95%.
（第１の色の色フィルターの形成）
　次に、第１の色の色フィルター（グリーンフィルター）の色フィルター用材料として、感光性硬化樹脂と熱硬化性樹脂を含ませたグリーン顔料分散液を１０００ｒｐｍの回転数でスピンコートした。この１色目の色フィルター用材料のグリーンの顔料には、カラーインデックスにてＣ．Ｉ．ＰＧ５８を用いており、その顔料濃度は７０質量％、膜厚は５００ｎｍであった。 (Formation of the color filter of the first color)
Next, a green pigment dispersion liquid containing a photosensitive curable resin and a thermosetting resin was spin-coated at a rotational speed of 1000 rpm as a color filter material of a first color filter (green filter). The green pigment of the first color material for the color filter has C.I. I. PG 58 was used, the pigment concentration was 70% by mass, and the film thickness was 500 nm.
　次に、グリーンフィルター用材料の硬化を実施するため、ｉ線の露光装置であるステッパーを用いて全面の露光を行い、感光性成分の硬化を実施した。この感光性成分の硬化により、グリーンフィルターの表面の硬化を実施した。続いて、ホットプレートで２３０℃で６分間ベークを行い、グリーンフィルターの熱硬化を行った。 Next, in order to cure the green filter material, the entire surface was exposed using a stepper which is an i-line exposure device to cure the photosensitive component. The surface of the green filter was cured by curing the photosensitive component. Subsequently, baking was performed at 230 ° C. for 6 minutes on a hot plate to thermally cure the green filter.
　実施例３では、この後実施例１と同様の手法で第１の色の色フィルターをドライエッチングでパターン加工した後、第２及び第３の色の色フィルター、上層の平坦化層及びマイクロレンズを形成し、実施例３の固体撮像素子を形成した。 In Example 3, after patterning the color filter of the first color by dry etching in the same manner as in Example 1, the color filter for the second and third colors, the flattening layer on the upper layer, and the microlens The solid-state imaging device of Example 3 was formed.
　上記の工程により、実施例３も実施例１同様に第１の色の色フィルターであるグリーンの膜厚Ａ（５００ｎｍ）とその下層の透明導電層の膜厚Ｂ（３０ｎｍ）、第２及び第３の色の色フィルターであるブルーとレッドの膜厚Ｃ（５５０ｎｍ）、可視光の透過率Ｄ（９５％）、隔壁の寸法Ｅ（３０ｎｍ）は、本発明の規定を満足している。 According to the above steps, the film thickness A (500 nm) of the green color filter of the first color and the film thickness B (30 nm) B of the transparent conductive layer therebelow of the third embodiment are the same as the first embodiment. The blue and red film thickness C (550 nm), the visible light transmittance D (95%), and the partition size E (30 nm), which are color filters of three colors, satisfy the definition of the present invention.
　本実施例の効果により、透明樹脂層で平坦化することにより、透明導電層を薄膜でも品質良く形成できており、ドライエッチングによるプラズマダメージは半導体基板に影響を与えない効果がある。また、副次的効果であるが、透明導電層の下層に透明樹脂層があることにより、透明樹脂層をウェットエッチングなどの公知の方法と除去することで、結晶化したＩＴＯなどの硬い透明導電層が容易に除去できる特徴がある。そのため、工程のやり直しなどプロセスマージンが広がる利点がある。 According to the effect of this embodiment, by flattening with the transparent resin layer, the transparent conductive layer can be formed with a thin film with good quality, and there is an effect that plasma damage by dry etching does not affect the semiconductor substrate. Moreover, although it is a secondary effect, when the transparent resin layer is under the transparent conductive layer, the transparent resin layer is removed by a known method such as wet etching to make hard transparent conductive such as crystallized ITO etc. There is a feature that the layer can be easily removed. Therefore, there is an advantage that the process margin can be expanded, such as reworking of the process.
　本実施例は、ブルー及びレッドで求める分光特性を得るために、グリーンよりも膜厚が厚く構成している。その為、図１５に示すようにグリーン、ブルー、レッドの高さがそろっている構造ではなく、ブルーとレッドが５０ｎｍ程度突き出す構造となった。 In this embodiment, the film thickness is thicker than that of green in order to obtain the spectral characteristics required for blue and red. Therefore, as shown in FIG. 15, the structure is not a structure in which the heights of green, blue and red are aligned, but a structure in which blue and red protrude by about 50 nm.
　＜従来法＞
　特許文献１に記載の従来法に基づき、フォトリソグラフィプロセスによって各色の色フィルターパターンを形成した。
　但し、グリーン、ブルー、レッドの三色の膜厚を７００ｎｍと薄膜に設定し、各色の色フィルター全部の下層に透明樹脂層（１００ｎｍ）を設けた。
　その他は、第１実施例と同様にして、従来法による固体撮像素子を製造した。 <Conventional method>
Based on the conventional method described in Patent Document 1, a color filter pattern of each color was formed by a photolithography process.
However, the film thickness of three colors of green, blue and red was set to a thin film of 700 nm, and a transparent resin layer (100 nm) was provided in the lower layer of all color filters of each color.
A solid-state imaging device was manufactured by the conventional method in the same manner as in the first embodiment except for the above.
（評価）
　以上の各実施例において、透明樹脂層の有無及び、透明樹脂層の形成位置の違い、透明樹脂層、透明導電層の高さ（厚み）の違いがあるが、グリーンの膜厚（５００ｎｍ）とその下層の透明導電層の膜厚（３０ｎｍから５０ｎｍ）、透明樹脂層の膜厚（３０ｎｍ）、第２及び第３の色の色フィルターであるブルーとレッドの膜厚（５５０ｎｍ）は、本発明で規定する膜厚を満足している。 (Evaluation)
In each of the above examples, the presence or absence of the transparent resin layer, the difference in the formation position of the transparent resin layer, and the difference in the height (thickness) of the transparent resin layer and the transparent conductive layer The film thickness (30 nm to 50 nm) of the lower transparent conductive layer, the film thickness (30 nm) of the transparent resin layer, and the film thicknesses of blue and red (550 nm) which are color filters of the second and third colors are the present invention. The film thickness specified in is satisfied.
　このような各実施例の固体撮像素子の赤色信号、緑色信号及び青色信号の強度について、従来法のフォトリソグラフィでグリーン、ブルー、レッドの三色の膜厚を７００ｎｍで分光特性を合わせた構造で作製した固体撮像素子の赤色信号、緑色信号及び青色信号の強度と比較評価をした。 With regard to the intensity of red signal, green signal and blue signal of the solid-state imaging device of each of the above-mentioned embodiments, the film characteristics of the three colors of green, blue and red are combined at 700 nm by the conventional photolithography. The intensities of the red, green and blue signals of the manufactured solid-state imaging device were compared and evaluated.
　以下の表１に図１、図１１及び図１５に示す上記第１から第３の実施形態係る固体撮像素子１，２，３に対応する実施例１から３に係る固体撮像素子における各色の信号強度の評価結果を表１に示す。表１に示す数値は、実施例１から３に係る固体撮像素子における各色の信号強度を従来法における固体撮像素子における各色の信号強度で規格化された値である。 Signals of the respective colors in the solid-state imaging device according to Examples 1 to 3 corresponding to the solid-state imaging devices 1, 2 and 3 according to the first to third embodiments shown in FIG. 1, FIG. 11 and FIG. The evaluation results of the strength are shown in Table 1. The numerical values shown in Table 1 are values obtained by standardizing the signal intensities of the respective colors in the solid-state imaging devices according to Examples 1 to 3 with the signal intensities of the respective colors in the solid-state imaging device in the conventional method.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、ドライエッチング法を用いて、グリーンフィルターを薄膜化及び矩形性良く形成して、さらにドライエッチングで発生した反応生成物を隔壁として形成した実施例１から実施例３の固体撮像素子では、従来法のフォトリソグラフィで形成した場合と比較して、各色の信号強度が増加した。これは、隔壁により、画素の斜め方向からの入斜光がカラーフィルタを通過して他のカラーフィルタパターンに向かう場合に、隔壁により入射が遮られるか、又は光路が変わるためである。このため、他のカラーフィルタパターンに向かう光が他の光電変換素子に入射することが抑制され、混色が抑制される。また、隔壁により、他色からの移染も隔壁によってブロックされるため、混色が抑制される。 As shown in Table 1, the solid of Example 1 to Example 3 in which the green filter was thinly formed with good rectangularity by using the dry etching method, and the reaction product generated by the dry etching was further formed as the partition wall. In the imaging device, the signal intensity of each color is increased as compared with the case of forming by the conventional photolithography. This is because, when the oblique light from the diagonal direction of the pixel passes through the color filter and travels to another color filter pattern by the partition, the incidence is blocked by the partition or the light path is changed. For this reason, it is suppressed that the light which goes to another color filter pattern injects into another photoelectric conversion element, and color mixing is suppressed. In addition, since color separation from other colors is also blocked by the partition wall, color mixing is suppressed.
　実施例１から実施例３の作製方法でＯＣＦ形成後に分光特性の評価をした結果、分光特性の変化は観察されなかった。これは、実施例１から３の熱硬化及び光硬化により、薄膜化したグリーンフィルターを十分に硬化しており、溶剤耐性を満たしていることを示している。薄膜化したグリーンフィルターでフォトリソグラフィ形成のグリーンフィルター膜厚（７００ｎｍ）と同等の色分光を行う為に、顔料含有率の高いグリーンフィルター用材料を使用したが分光特性の変化は発生せず、薄膜化の効果によりマイクロレンズトップからデバイスまでの距離が短くなりグリーンの信号強度が増加した。
　また、薄膜化によっても斜め方向からの入斜光が色フィルターを通過して他の色フィルターパターンに向かう確率が低下し、他の色フィルターパターンに向かう光が他の光電変換素子に入射することが抑制され、混色を抑制したため信号強度が増加した。 As a result of evaluating the spectral characteristics after OCF formation by the manufacturing methods of Example 1 to Example 3, no change in the spectral characteristics was observed. This indicates that the thin-filmed green filter is sufficiently cured by the thermal curing and photocuring of Examples 1 to 3 and the solvent resistance is satisfied. A green filter material with a high pigment content was used to perform color spectroscopy equivalent to that of a green filter film thickness (700 nm) formed by photolithography using a thinned green filter, but no change in the spectral characteristics occurs, and a thin film As a result, the distance from the top of the microlens to the device is shortened and the signal strength of the green is increased.
In addition, the probability that incident light from an oblique direction passes through a color filter and travels to another color filter pattern is reduced by thinning as well, and light traveling to another color filter pattern may be incident on another photoelectric conversion element. Since the suppression was performed and the color mixing was suppressed, the signal intensity increased.
　また、実施例１から実施例３の手法を用いて、透明導電層及び透明樹脂層の形成位置の変更により若干の受光感度の変化が確認された。しかし、どの構成の実施例に置いても、ドライエッチングによるプラズマダメージの受光感度への影響は確認されなかった。
第２の色の色フィルター１５及び第３の色の色フィルター１６の高さが第１の色の色フィルター１４と透明樹脂層３０および透明導電層１２の膜厚を足した値より低い高さで色フィルターを形成した場合においても、膜厚を薄くした分、顔料含有率を高くする事で、従来手法のフォトリソグラフィで形成した場合と比較して、信号強度が増加した。 Moreover, the change of the light reception sensitivity was confirmed slightly by the change of the formation position of a transparent conductive layer and a transparent resin layer using the method of Example 1 to Example 3. FIG. However, in any of the configuration examples, the influence of plasma damage due to dry etching on the photosensitivity was not confirmed.
The height of the color filter 15 of the second color and the color filter 16 of the third color is lower than the sum of the film thickness of the color filter 14 of the first color and the transparent resin layer 30 and the transparent conductive layer 12 Even in the case where the color filter was formed, the signal content was increased by increasing the pigment content as much as the film thickness was reduced, as compared with the case of forming by photolithography in the conventional method.
　以上、各実施形態により本発明を説明したが、本発明の範囲は、図示され記載された例示的な実施形態に限定されるものではなく、本発明が目的とするものと均等な効果をもたらす全ての実施形態をも含む。さらに、本発明の範囲は、請求項により画される発明の特徴の組み合わせに限定されるものではなく、全ての開示されたそれぞれの特徴のうち特定の特徴のあらゆる所望する組み合わせによって画されうる。 Although the present invention has been described above by the respective embodiments, the scope of the present invention is not limited to the illustrated and described exemplary embodiments, and effects equivalent to those aimed by the present invention are achieved. Also includes all embodiments. Furthermore, the scope of the present invention is not limited to the combination of the features of the invention as defined by the claims, but can be defined by any desired combination of particular features of all the disclosed respective features.
　１０・・・半導体基板
　１１・・・光電変換素子
　１２・・・透明導電層
　１３・・・平坦化層
　１４・・・第１の色の色フィルター
　１５・・・第２の色の色フィルター
　１６・・・第３の色の色フィルター
　１７・・・隔壁
　１８・・・マイクロレンズ
　１９・・・マイクロレンズ母型層
　２０・・・エッチングマスク
　３０・・・透明樹脂層 DESCRIPTION OF SYMBOLS 10 ... Semiconductor substrate 11 ... Photoelectric conversion element 12 ... Transparent conductive layer 13 ... Flattening layer 14 ... Color filter of 1st color 15 ... Color filter 16 of 2nd color ... Third color filter 17 ... partition 18 ... micro lens 19 ... micro lens matrix layer 20 ... etching mask 30 ... transparent resin layer

Claims (19)

  1. 　複数の光電変換素子を二次元的に配置した半導体基板と、
    　上記半導体基板上に形成され、上記複数の光電変換素子に対応させて複数色の色フィルターを予め設定した規則パターンで二次元的に配置した色フィルター層と、
    　上記複数色から選択した第１の色の色フィルターと半導体基板との間に配置された透明導電層と、
    　を備えることを特徴する固体撮像素子。     A semiconductor substrate on which a plurality of photoelectric conversion elements are two-dimensionally arranged;
    A color filter layer formed on the semiconductor substrate and two-dimensionally arranged in a regular pattern having a plurality of color filters set in advance in correspondence with the plurality of photoelectric conversion elements;
    A transparent conductive layer disposed between the color filter of the first color selected from the plurality of colors and the semiconductor substrate;
    A solid-state imaging device comprising:
  2. 　上記透明導電層のシート抵抗をＦとした場合に下記（１）式を満足することを特徴とする請求項１に記載の固体撮像素子。
    　Ｆ＜１０００００　Ω／□　・・・（１）     When the sheet resistance of the said transparent conductive layer is set to F, the following (1) Formula is satisfied, The solid-state image sensor of Claim 1 characterized by the above-mentioned.
    F <100000 Ω / □ (1)
  3. 　上記透明導電層は、珪素、炭素、酸素、水素、錫、亜鉛、インジウム、アルミニウム、ガリウム、チタン、モリブデン、タングステン、カドミウム、ニオブ、タンタル、ハフニウム、銀、フッ素から選ばれる少なくとも１種類を含有する化合物が単層又は複層で形成されることを特徴とする請求項１又は請求項２に記載の固体撮像素子。 The transparent conductive layer contains at least one selected from silicon, carbon, oxygen, hydrogen, tin, zinc, indium, aluminum, gallium, titanium, molybdenum, tungsten, cadmium, niobium, tantalum, hafnium, silver, and fluorine. The solid-state imaging device according to claim 1 or 2, wherein the compound is formed of a single layer or a plurality of layers.
  4. 　上記透明導電層及び上記第１の色の色フィルターは、上記透明導電層のエッチングレートをＴとし、上記第１の色の色フィルターのエッチングレートをＧとしたとき、フッ素、酸素、水素、硫黄、炭素、臭素、塩素、窒素、アルゴン、ヘリウム、キセノン、クリプトンから選ばれる少なくとも１種類を含有するガスを用いたドライエッチングにおいて、下記（２）式を満足する材料構成となっていることを特徴とする請求項１から請求項３のいずれか１項に記載の固体撮像素子。
    　３≦Ｇ／Ｔ　　・・・（２）     When the transparent conductive layer and the color filter of the first color have an etching rate of the transparent conductive layer as T and an etching rate of the color filter of the first color as G, fluorine, oxygen, hydrogen, sulfur In dry etching using a gas containing at least one selected from carbon, bromine, chlorine, nitrogen, argon, helium, xenon, and krypton, the material configuration is such that the following formula (2) is satisfied: The solid-state imaging device according to any one of claims 1 to 3, wherein
    3 ≦ G / T (2)
  5. 　上記複数色の色フィルターの間に配置した隔壁を更に備えることを特徴する請求項１から請求項４のいずれか１項に記載した固体撮像素子。 The solid-state imaging device according to any one of claims 1 to 4, further comprising a partition arranged between the color filters of the plurality of colors.
  6. 　上記隔壁は、亜鉛、銅、ニッケル、珪素、炭素、酸素、水素、窒素、臭素、塩素、インジウム、錫から選ばれる少なくとも１種類を含有することを特徴とする請求項５に記載の固体撮像素子。 The solid-state imaging device according to claim 5, wherein the partition wall contains at least one selected from zinc, copper, nickel, silicon, carbon, oxygen, hydrogen, nitrogen, bromine, chlorine, indium, and tin. .
  7. 　上記第１の色の色フィルターの膜厚をＡ［ｎｍ］、上記透明導電層の膜厚をＢ［ｎｍ］、上記第１の色以外の色の色フィルターの膜厚をＣ［ｎｍ］、上記透明導電層の可視光の透過率をＤ［％］、上記隔壁の寸法をＥ［ｎｍ］とした場合に、下記（３）～（７）式を満足することを特徴とする請求項５又は請求項６に記載の固体撮像素子。
    　２００［ｎｍ］≦Ａ≦７００［ｎｍ］　　　　　　　　　・・・（３）
    　０［ｎｍ］＜Ｂ≦２００［ｎｍ］　　　　　　　　　　　・・・（４）
    　Ａ＋Ｂ－２００［ｎｍ］≦Ｃ≦Ａ＋Ｂ＋２００［ｎｍ］　・・・（５）
    　Ｄ≧８０［％］・・・（６）
    　Ｅ≦２００［ｎｍ］・・・（７）     The film thickness of the first color filter is A [nm], the film thickness of the transparent conductive layer is B [nm], the film thickness of color filters of colors other than the first color is C [nm], When the transmittance of visible light of the transparent conductive layer is D [%] and the dimension of the partition is E [nm], the following formulas (3) to (7) are satisfied. Or the solid-state image sensor of Claim 6.
    200 [nm] ≦ A ≦ 700 [nm] (3)
    0 [nm] <B ≦ 200 [nm] (4)
    A + B-200 [nm] ≦ C ≦ A + B + 200 [nm] (5)
    D 80 80 [%] (6)
    E ≦ 200 [nm] (7)
  8. 　上記透明導電層と上記第１の色の色フィルターとの間に、更に透明樹脂層を備えることを特徴する請求項５から請求項７のいずれか１項に記載の固体撮像素子。 The solid-state imaging device according to any one of claims 5 to 7, further comprising a transparent resin layer between the transparent conductive layer and the color filter of the first color.
  9. 　上記透明導電層と上記半導体基板との間に、更に透明樹脂層を備えることを特徴する請求項２から請求項６のいずれか１項に記載の固体撮像素子。 The solid-state imaging device according to any one of claims 2 to 6, further comprising a transparent resin layer between the transparent conductive layer and the semiconductor substrate.
  10. 　上記透明樹脂層は珪素、炭素、酸素、水素から選ばれる少なくとも１種類を含有することを特徴とする請求項８又は請求項９に記載の固体撮像素子。 The solid-state imaging device according to claim 8, wherein the transparent resin layer contains at least one selected from silicon, carbon, oxygen, and hydrogen.
  11. 　上記第１の色の色フィルターには、熱硬化性樹脂を含有することを特徴とする請求項１から請求項１０のいずれか１項に記載の固体撮像素子。 The solid-state imaging device according to any one of claims 1 to 10, wherein the color filter of the first color contains a thermosetting resin.
  12. 　上記第１の色の色フィルターには、熱硬化性樹脂及び光硬化性樹脂を含有し、光硬化性樹脂の含有量よりも熱硬化性樹脂の含有量の方が多いことを特徴とする請求項１から請求項１０のいずれか１項に記載の固体撮像素子。 The color filter of the first color contains a thermosetting resin and a photocurable resin, and the content of the thermosetting resin is larger than the content of the photocurable resin. The solid-state imaging device according to any one of items 1 to 10.
  13. 　上記第１の色の色フィルターには、光硬化性樹脂を含有することを特徴とする請求項１から請求項１０のいずれか１項に記載の固体撮像素子。 The solid-state imaging device according to any one of claims 1 to 10, wherein the color filter of the first color contains a photocurable resin.
  14. 　上記第１の色の色フィルターは、着色剤である顔料の濃度が５０質量％以上であることを特徴とする請求項１から請求項１３のいずれか１項に記載の固体撮像素子。 The solid-state imaging device according to any one of claims 1 to 13, wherein the color filter of the first color has a concentration of a pigment which is a coloring agent of 50% by mass or more.
  15. 上記色フィルター層上に、上記光電変換素子のそれぞれに対応して二次元的に配置されたマイクロレンズを有し、上記マイクロレンズのレンズトップからレンズボトムまでの高さが３００ｎｍ以上８００ｎｍ以下の範囲であることを特徴とする請求項１から請求項１４のいずれか１項に記載の固体撮像素子。 A microlens having a two-dimensional arrangement corresponding to each of the photoelectric conversion elements is provided on the color filter layer, and the height from the lens top to the lens bottom of the microlens ranges from 300 nm to 800 nm. The solid-state imaging device according to any one of claims 1 to 14, wherein
  16. 　上記複数色の色フィルターのうち、上記第１の色の色フィルターの専有面積が一番広いことを特徴とする請求項１から請求項１５のいずれか１項に記載の固体撮像素子。 The solid-state imaging device according to any one of claims 1 to 15, wherein an area occupied by the first color filter is the largest among the plurality of color filters.
  17. 　複数の光電変換素子を二次元的に配置した半導体基板に透明導電層を形成し、上記透明導電層上に第１の色の色フィルター用の塗布液を塗布し硬化させて透明導電層及び第１の色の色フィルター層をこの順に形成した後、上記第１の色の色フィルターの配置位置以外の上記第１の色の色フィルター層部分をドライエッチングによって除去して第１の色の色フィルターをパターン形成する第１の工程と、
    　上記第１の色の色フィルターをパターン形成する第１の工程において、上記第１の色の色フィルター層をドライエッチングする際に生じる色フィルター層とドライエッチングガスの副生成物を、上記第１の色の色フィルターの側壁に隔壁として形成する第２の工程と、
    　第２の工程後に、第１の色の以外の色の色フィルターを、フォトリソグラフィによってパターニングして形成する第３の工程と、
    　を備えることを特徴とする固体撮像素子の製造方法。     A transparent conductive layer is formed on a semiconductor substrate in which a plurality of photoelectric conversion elements are two-dimensionally arranged, and a coating solution for a first color filter is applied on the transparent conductive layer and cured to form a transparent conductive layer After forming the color filter layer of 1 color in this order, the color filter layer portion of the first color other than the arrangement position of the first color filter is removed by dry etching to form the first color A first step of patterning the filter;
    In the first step of patterning the color filter of the first color, the color filter layer and the by-product of the dry etching gas, which are generated when the color filter layer of the first color is dry-etched, Forming a partition wall on the side wall of the color filter of
    After the second step, forming a color filter of a color other than the first color by photolithography and forming a third step;
    A method of manufacturing a solid-state imaging device, comprising:
  18. 　複数の光電変換素子を二次元的に配置した半導体基板に透明導電層を形成し、上記透明導電層上に透明樹脂層を形成し、第１の色の色フィルター用の塗布液を塗布し硬化させて、透明導電層、透明樹脂層及び第１の色の色フィルター層をこの順に形成した後、第１の色の色フィルターの配置位置以外の上記第１の色の色フィルター層部分及び該第１の色の色フィルター層部分の下層に位置する透明樹脂層をドライエッチングによって除去して第１の色の色フィルターをパターン形成する第１の工程と、
    　上記第１の色の色フィルターをパターン形成する第１の工程において、上記第１の色の色フィルター層及びその除去する色フィルター層部分の下層に位置する透明樹脂層をドライエッチングする際に生じる色フィルター層及び透明樹脂層とドライエッチングガスの副生成物を、上記第１の色の色フィルターの側壁に隔壁として形成する第２の工程と、
    　第２の工程後に、第１の色以外の色の色フィルターを、フォトリソグラフィによってパターニングして形成する第３の工程と、
    　を備えることを特徴とする固体撮像素子の製造方法。     A transparent conductive layer is formed on a semiconductor substrate in which a plurality of photoelectric conversion elements are two-dimensionally arranged, a transparent resin layer is formed on the transparent conductive layer, and a coating solution for a first color color filter is applied and cured. And forming a transparent conductive layer, a transparent resin layer, and a color filter layer of the first color in this order, followed by the color filter layer portion of the first color other than the arrangement position of the color filter of the first color, and A first step of removing a transparent resin layer located under the first color filter layer portion by dry etching to pattern the first color filter;
    In the first step of patterning the color filter of the first color, it occurs when the transparent resin layer located under the color filter layer of the first color and the color filter layer portion to be removed is dry-etched A second step of forming a color filter layer, a transparent resin layer and a by-product of a dry etching gas as a partition wall on the side wall of the first color filter;
    After the second step, forming a color filter of a color other than the first color by photolithography and forming a third step;
    A method of manufacturing a solid-state imaging device, comprising:
  19. 　上記第１の色の色フィルターの硬化時の加熱温度が１７０℃以上２７０℃以下であることを特徴とする請求項１７又は請求項１８に記載の固体撮像素子の製造方法。 The method for manufacturing a solid-state imaging device according to claim 17 or 18, wherein a heating temperature at the time of curing of the color filter of the first color is 170 ° C or more and 270 ° C or less.
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