WO2012070165A1 - Solid-state imaging device and method for fabricating same - Google Patents

Solid-state imaging device and method for fabricating same Download PDF

Info

Publication number
WO2012070165A1
WO2012070165A1 PCT/JP2011/002522 JP2011002522W WO2012070165A1 WO 2012070165 A1 WO2012070165 A1 WO 2012070165A1 JP 2011002522 W JP2011002522 W JP 2011002522W WO 2012070165 A1 WO2012070165 A1 WO 2012070165A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
refractive index
solid
imaging device
state imaging
Prior art date
Application number
PCT/JP2011/002522
Other languages
French (fr)
Japanese (ja)
Inventor
雅之 高瀬
勝野　元成
平井　純
矢野　尚
鈴木　繁
Original Assignee
パナソニック株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by パナソニック株式会社 filed Critical パナソニック株式会社
Publication of WO2012070165A1 publication Critical patent/WO2012070165A1/en

Links

Images

Classifications

    • 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
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14629—Reflectors
    • 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
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14627—Microlenses
    • 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
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/14685—Process for coatings or optical elements

Definitions

  • the present invention relates to a solid-state imaging device including an optical waveguide and a manufacturing method thereof.
  • FIG. 12 is a partial cross-sectional view showing the configuration of the solid-state imaging device 1100 of Patent Document 1.
  • a light receiving unit 1a including a silicon oxide film, polysilicon, and three silicon nitride layers having different film qualities on a semiconductor substrate (not shown)
  • a sensor unit 1 having a silicon oxide film 1b covering the light receiving unit 1a is formed.
  • An interlayer insulating film 3 made of a laminated body of a silicon oxide film and a silicon nitride film or the like is formed on the sensor unit 1, and in the interlayer insulating film 3, a plurality of wiring layers 2 ( The wiring layer 2a, the wiring layer 2b, and the wiring layer 2c) are embedded.
  • the wiring layer 2a and the light receiving portion 1a are electrically connected by a contact plug V1
  • the wiring layer 2a and the wiring layer 2b are electrically connected by a contact plug V2
  • the wiring layer 2b and the wiring layer 2c are electrically connected by a contact plug V3, respectively. ing.
  • a protective film 4 is formed on the interlayer insulating film 3, and a TiO dispersed polyimide portion 5 having a refractive index higher than the refractive index of the material constituting the interlayer insulating film 3 is formed on the protective film 4. Is formed.
  • the TiO-dispersed polyimide portion 5 has a configuration in which a part extends toward the light receiving portion 1a (hereinafter, a portion 5a extending from the surface region of the protective film 4 toward the light receiving portion 1a is referred to as “light guide”. "Waveguide").
  • a color filter 8 is formed on the TiO-dispersed polyimide 5 via an acrylic thermosetting resin 7, and an on-chip lens 9 is formed on the color filter 8.
  • the light incident on the lens 9 is basically condensed in the optical waveguide 5a.
  • the light-receiving part 1a is reached through the optical waveguide 5a.
  • not all of the light is collected in the optical waveguide 5a, and a part of the light does not enter the optical waveguide 5a and is shifted from the optical waveguide 5a (that is, the upper surface of the protective film 4). Head to).
  • light incident obliquely on the upper surface of the protective film 4 may be mixed into adjacent optical waveguides (so-called color mixing).
  • the TiO-dispersed polyimide portion 5 Since the TiO-dispersed polyimide portion 5 is present on the protective film 4, light incident obliquely toward the upper surface of the protective film 4 is between the protective film 4 and the acrylic thermosetting resin 7 or the bottom surface of the color filter 8. Is reflected in the direction of the adjacent optical waveguide.
  • the amount of light reaching the light receiving unit corresponding to the adjacent optical waveguide is increased by the amount of mixed light, so that it is difficult to accurately reproduce the color and the image quality is deteriorated.
  • the present invention solves the above-described problems, and provides a solid-state imaging device that suppresses deterioration in image quality due to color mixing.
  • a solid-state imaging device which is one embodiment of the present invention includes a semiconductor substrate having a plurality of photoelectric conversion portions formed in a matrix and the plurality of photoelectric conversion devices formed on the semiconductor substrate.
  • the first refractive index interlayer insulating film having a hole formed in a portion corresponding to the upper part of each conversion portion, and the first refractive index interlayer insulating film filling each hole and rising from the interlayer insulating film.
  • a plurality of optical waveguides having a second refractive index higher than the refractive index, and a flat third having a third refractive index lower than the second refractive index, formed on the plurality of optical waveguides and between adjacent optical waveguides.
  • a chemical film is one embodiment of the present invention.
  • each of the plurality of optical waveguides is substantially independent.
  • the fact that each of the plurality of optical waveguides is substantially independent means that there is no optical path for light incident on one optical waveguide to propagate from the optical waveguide to an adjacent optical waveguide. Therefore, as shown in FIGS. 1, 8, as shown in FIGS. 4, 6, 10, and 11, as long as light is not propagated, as well as the space between adjacent optical waveguides 30 is filled with the planarizing film 40.
  • the optical waveguide refers only to a so-called core portion that serves as a light path.
  • the solid-state imaging device there are a plurality of optical waveguides that fill each hole portion of the interlayer insulating film and have a raised portion than the interlayer insulating film.
  • a planarizing film is formed between the upper and adjacent optical waveguides. Therefore, even if the light incident on one optical waveguide does not go into the hole but goes in the direction of the adjacent optical waveguide, it is reflected by the planarizing film existing between the optical waveguides and collected in the hole. It will be lighted.
  • the interlayer insulating film may include a wiring layer therein, and the plurality of optical waveguides may be continuously formed across the plurality of photoelectric conversion units. .
  • the entire surface of the interlayer insulating film is covered with a material having a higher refractive index than the first and third refractive indexes.
  • portions of the plurality of optical waveguides that are higher than the interlayer insulating film may have a lens shape.
  • the optical waveguide itself can have the same light collecting ability as the lens.
  • FIG. 1 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 100 according to Embodiment 1.
  • FIG. 4 is a diagram illustrating a part of a manufacturing process of the solid-state imaging device 100.
  • FIG. FIG. 3 is a diagram illustrating a portion subsequent to the portion illustrated in FIG. 2 in the manufacturing process of the solid-state imaging device 100.
  • 6 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 200 according to Embodiment 2.
  • FIG. 6 is a diagram illustrating a manufacturing process of the solid-state imaging device 200.
  • FIG. FIG. 10 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 201 of Modification 2-1.
  • FIG. 11 is a diagram illustrating a manufacturing process of the solid-state imaging device 201.
  • 6 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 300 according to Embodiment 3.
  • FIG. 6 is a diagram illustrating a manufacturing process of the solid-state imaging device 300.
  • FIG. 2 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 400.
  • FIG. 2 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 500.
  • FIG. FIG. 11 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 1100 of Patent Document 1.
  • FIG. 1 is a partial cross-sectional view illustrating the configuration of the solid-state imaging device 100 according to the first embodiment.
  • the solid-state imaging device 100 includes a semiconductor substrate 10 having a plurality of photoelectric conversion units 11 formed in a matrix, an interlayer insulating film 20 formed on the semiconductor substrate 10, and an interlayer insulating film 20.
  • the color filter 50 is formed by dispersing a pigment in an organic material, and the microlens 60 is formed on the color filter 50 and collects incident light on the photoelectric conversion unit 11.
  • the interlayer insulating film 20 is a stacked body in which a plurality of films are stacked, and each film is also referred to as a refractive index lower than the refractive index of a material constituting the optical waveguide 30 described later (hereinafter also referred to as “first refractive index”). ) Material. Examples of the material include silicon oxide, silicon nitride, and silicon carbide.
  • the interlayer insulating film 20 has a concave portion 23 in the surface region that is above the photoelectric conversion portion 11 (hereinafter, the concave portion is referred to as a “hole portion”, and has a mountain shape opposite to the hole portion 23.
  • the portion 24 is also referred to as a “projection”.
  • a plurality of wiring layers 21 (wiring layer 21 a and wiring layer 21 b) are formed in the internal region, and these wiring layers 21 are located above the adjacent photoelectric conversion units 11 in the interlayer insulating film 20. It is located in the part (that is, in the protrusion 24). This is because the incident of light on the photoelectric conversion unit 11 is not hindered.
  • the optical waveguide 30 is translucent and has a higher refractive index (hereinafter also referred to as “second refractive index”) than the refractive index of the material constituting the interlayer insulating film 20 and the planarizing film 40 described later. Consists of. Examples of the material include organic materials containing TiO, such as TiO-dispersed polyimide, or silicon nitride.
  • the optical waveguide 30 is formed in the hole 23 of the interlayer insulating film 20 and above the interlayer insulating film 20, and a portion of the optical waveguide 30 formed above the interlayer insulating film 20 (ie, protruding from the hole 23).
  • the raised part has a trapezoidal shape.
  • a part of the optical waveguide 30 is in a state of riding on the upper surface of the end portion of the protruding portion 24.
  • the adjacent optical waveguides 30 are not in contact with each other on the protruding portion 24 of the interlayer insulating film 20 and exist at positions separated from each other. That is, each of the optical waveguides 30 is in an independent state.
  • the planarization film 40 is provided to adjust the surface step between the interlayer insulating film 20 and the optical waveguide 30 to be flat, and has a refractive index lower than the refractive index of the material constituting the optical waveguide 30 (hereinafter referred to as “third refraction”). It is also referred to as “rate”.)
  • the material include acrylic thermosetting resins.
  • the planarization film 40 partially fills the gap between the adjacent optical waveguides 30, thereby separating the adjacent optical waveguides 30 (hereinafter, between the adjacent optical waveguides 30 in the planarization film 40.
  • the portion 41 that fills in is described as a “partition wall”.)
  • the interlayer insulating film 20 and the planarizing film 40 function as a cladding portion.
  • the cladding portion includes not only the interlayer insulating film 20 but also the planarization film 40.
  • the cladding portion extends in the stacking direction by the thickness of the partition wall portion 41 of the planarization film 40 filling between the adjacent optical waveguides 30.
  • the optical waveguide 30 also extends in the stacking direction. It has become.
  • the light L1 directed toward the upper surface of the protrusion 24 without being directed into the hole 23 of the interlayer insulating film 20 is flattened.
  • the light is reflected by the partition wall 41 of the film 40 and goes into the hole 23. Since the amount of light toward the adjacent optical waveguides 30 is reduced by the amount of the optical waveguides 30 extending in the stacking direction, color mixing can be suppressed.
  • the inner angle ang1 formed by the end of the portion of the optical waveguide 30 that rides on and the upper surface of the protrusion 24 is preferably as close to a right angle as possible. This is because as the inner angle ang1 is closer to a right angle, the width of the upper surface of the optical waveguide 30 becomes wider, so that the area of the optical waveguide 30 increases and more light can be collected in the optical waveguide 30.
  • the width wid1 of one cell 80 is, for example, 1.4 ⁇ m, and the width wid2 of the upper surface of the optical waveguide 30 is 1.1 to 1.2 ⁇ m.
  • the width wid3 of the widest portion between the adjacent optical waveguides 30 is preferably narrower within a wider range than the amount of light leakage described later, and is, for example, 191 to 300 nm. This is because the narrower the width is, the wider the region of the optical waveguide 30 is, and more light can be collected in the optical waveguide 30.
  • the thickness th1 of the portion formed above the interlayer insulating film 20 in the optical waveguide 30 is preferably thicker, for example, 200 to 400 nm.
  • the thickness th2 of the portion of the planarizing film 40 located on the upper surface of the optical waveguide 30 is preferably thinner, for example, 100 nm. This is because when the optical waveguide 30 approaches the microlens 60, light traveling from the lens 60 toward the adjacent optical waveguide 30 can be reduced, and color mixing can be further suppressed.
  • Wp ⁇ / ( ⁇ ⁇ (Nf 2 ⁇ Ns 2 ) 0.5 ) (Formula 1)
  • Wp is the amount of light leakage
  • ⁇ is the wavelength of light in vacuum
  • Nf is the refractive index of the optical waveguide 30
  • Ns is the refractive index of the planarizing film 40 that is the cladding.
  • a plurality of photoelectric conversion portions 11 are formed in a matrix in the semiconductor substrate 10.
  • a laminate film 20a made of a laminate of a plurality of films is formed by a CVD (Chemical Vapor Deposition) method or the like.
  • a plurality of wiring layers 21 are also formed in the multilayer film 20a by the damascene method. More specifically, first, a groove for forming a wiring is formed by etching in one layer of the laminate constituting the laminate film 20a. Then, a barrier metal film serving as a seed layer is formed on the bottom and side surfaces of the groove.
  • a resist pattern 501 for opening a portion corresponding to the upper side of the photoelectric conversion unit 11 in the multilayer film 20a is formed by a lithography process.
  • the hole 23 is formed by etching the stacked body film 20a by RIE (reactive ion etching) or the like, thereby forming a step in the surface region of the stacked body film 20a.
  • RIE reactive ion etching
  • FIG. 2C an interlayer insulating film 20 in which a portion corresponding to the upper side of the photoelectric conversion portion 11 is depressed in the surface region can be formed.
  • the depth 23a of the hole formed by this etching is, for example, about 400 nm to 600 nm.
  • a refractive index higher than the refractive index of the material constituting the interlayer insulating film 20 is formed on the interlayer insulating film 20 as a second refractive index material film (first transparent film).
  • An optical waveguide material film 30a made of a material having a constant ratio is formed.
  • the optical waveguide material film 30a preferably has a thickness sufficient to suppress variations in the film thickness of the optical waveguide material film 30a. Specifically, the entire surface region is higher than the upper surface 22 of the protrusion 24.
  • the optical waveguide material film 30a may be planarized by, for example, CMP or etch back.
  • FIG. 3A for example, after a resist pattern 502 for opening an upper portion between adjacent photoelectric conversion portions 11 in the optical waveguide material film 30a is formed by a lithography process, An etching process such as RIE is performed. As a result, as shown in FIG. 3B, the portion 32 of the optical waveguide material film 30 a that hits between the adjacent photoelectric conversion portions 11 is removed, and each hole portion 23 of the interlayer insulating film 20 has each of the holes 23. It is possible to form the optical waveguide 30 that fills the hole portion 23 and has a portion that is higher than the interlayer insulating film 20.
  • a flattening film 40 is formed, and a color filter is formed on the flattening film 40. 50 is formed.
  • microlens 60 is formed on the color filter 50 as shown in FIG.
  • the solid-state imaging device 100 having the configuration shown in FIG. 1 can be manufactured.
  • the adjacent optical waveguides 30 are not in contact with each other on the protruding portion 24 of the interlayer insulating film 20 and exist at positions separated from each other. Therefore, on the surface region of the interlayer insulating film 20, there was a portion where a region made of the material having the second refractive index was not formed. Then, moisture may permeate from a region exposed from the material without being covered with the second refractive index material, and the moisture may accelerate deterioration of the wiring layer 21.
  • FIG. 4 is a partial cross-sectional view showing the configuration of the solid-state imaging device 200 according to the second embodiment.
  • the solid-state imaging device 200 of the present embodiment is different except that the entire surface region of the interlayer insulating film 20 is covered with a film 30b made of a material having a second refractive index.
  • the configuration is the same as that of the solid-state imaging device 100 of the first embodiment. Therefore, in FIG. 4, the description of the same components as those of the solid-state imaging device 100 according to the first embodiment will be omitted, and the following description will focus on the different portions.
  • the film 30b made of the material having the second refractive index is formed over the entire surface region of the interlayer insulating film 20.
  • the film 30b is denser than the film made of these materials and has a barrier against moisture. High nature. Since such a film 30b is formed over the entire surface region of the interlayer insulating film 20, moisture penetrating into the interlayer insulating film 20 can be reduced, and the wiring layer 21 existing in the interlayer insulating film 20 can be reduced. Deterioration due to moisture can be suppressed.
  • a part of the film 30b that is, each of the parts that contact the photoelectric conversion unit 11 forms the optical waveguide 30.
  • the thickness th1 of the portion of the optical waveguide 30 that protrudes from the recessed portion of the interlayer insulating film 20 is a portion 33 (hereinafter simply referred to as “part”) other than the portion that forms the optical waveguide 30. It is thicker than the film thickness th3.
  • the limitation on the film thickness th3 of the portion 33 will be described. From an optical viewpoint, the thickness th3 of the portion 33 needs to be a thickness that does not propagate light. This is because light is not propagated to the adjacent optical waveguide 30 through the portion 33.
  • the portion 33 in the film 30b is preferably thick. This is because the barrier property against moisture can be improved.
  • the thickness th3 of the portion 33 is preferably in the range of several nm to several tens of nm.
  • the wavelength of visible light is about 400 nm to about 800 nm
  • the thickness th3 of the portion 33 is 50 nm
  • the film thickness is 1/8 of the wavelength for any wavelength of visible light. It becomes as follows. Since this is sufficiently thin with respect to the wavelength of visible light, it is considered that a color mixing prevention effect can be sufficiently obtained without causing optical degradation. Moreover, deterioration of the wiring layer 21 due to moisture can be suppressed.
  • FIG. 5 is a cross-sectional view showing the configuration of the solid-state imaging device 200 at each step in the manufacturing method.
  • a resist pattern 502 for opening an upper portion between adjacent photoelectric conversion portions 11 is formed by a lithography process, and then an etching process such as RIE is performed. However, at this time, the etching rate is adjusted, and a part of the film 30a is left on the surface of the portion of the interlayer insulating film 20 that is located between the adjacent photoelectric conversion portions 11. Thereby, as shown in FIG. 5A, a film 30 b made of a material having the second refractive index can be formed over the entire surface region of the interlayer insulating film 20.
  • the portion 33 of the film 30 b is made of the same material as the optical waveguide 30 and is formed in the same process as the optical waveguide 30. Therefore, an increase in the number of steps accompanying the formation of the portion 33 of the film 30b can be suppressed. Therefore, the deterioration of the wiring layer 21 can be suppressed without adding a separate process.
  • the flattening film 40 is formed, and the color filter 50 is formed on the flattening film 40.
  • the micro lens 60 is formed on the color filter 50.
  • FIG. 6 is a partial cross-sectional view showing the configuration of the solid-state imaging device 201 of Modification 2-1.
  • the solid-state imaging device 201 of the present embodiment has basically the same configuration as that of the solid-state imaging device 100 of the first embodiment except that a wiring protective film 90 is provided. . Therefore, in FIG. 6, the description of the same components as those of the solid-state imaging device 100 according to Embodiment 1 will be omitted, and the following description will focus on the different portions.
  • the wiring protective film 90 is formed so as to cover all the optical waveguides 30 formed in the respective holes 23 of the interlayer insulating film 20, and is made of a material having a second refractive index, like the optical waveguide 30. That is, the entire surface of the interlayer insulating film 20 is covered with the wiring protective film 90 made of a material having the second refractive index. Further, since the wiring protective film 90 is formed along the optical waveguide 30, there is a step in the surface region, and the planarizing film 40 is formed in order to adjust the surface step to be flat.
  • the limitation on the thickness of the portion between the adjacent optical waveguides 30 in the wiring protective film 90 is the same as that of the portion 33 of the film 30b, and thus the description thereof is omitted here.
  • the wiring protective film 90 is made of a material having the second refractive index, but any material having a refractive index higher than the first and third refractive indexes may be used. 2-1-2. Next, a method for manufacturing the solid-state imaging device 201 will be described.
  • FIG. 7 is a cross-sectional view illustrating the configuration of the solid-state imaging device 201 at each step in the manufacturing method.
  • a wiring protective film 90 made of the same material as that of the optical waveguide 30 is formed over the entire surface, as shown in FIG.
  • the variation in the film thickness between the optical waveguides 30 due to etching can be reduced.
  • the etching process may be stopped at a position where the film material is different, that is, when the upper surface 22 of the protruding portion 24 of the interlayer insulating film 20 is exposed, so that the etching can be stopped with high accuracy. is there. Thereby, the difference of the optical characteristic between cells can also be suppressed, suppressing deterioration of the wiring layer 21.
  • the planarizing film 40, the color filter 50, and the microlens 60 are formed.
  • FIG. 8 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 300 according to the third embodiment.
  • the solid-state imaging device 300 of the present embodiment is basically the same as that of the first embodiment except that the shape of the portion formed above the interlayer insulating film 20 in the optical waveguide 30 is different.
  • the configuration is the same as that of the solid-state imaging device 100. Therefore, in FIG. 8, the description of the same components as those of the solid-state imaging device 100 according to the first embodiment will be omitted, and the following description will focus on the different portions.
  • the shape of the portion 34 formed above the interlayer insulating film 20 is a convex lens shape.
  • the optical waveguide 30 itself can have the same light collecting ability as that of the lens, the light incident on the optical waveguide 30 can be guided in a more vertical direction.
  • FIG. 9 is a cross-sectional view showing the configuration of the solid-state imaging device 300 at each step in the manufacturing method.
  • a resist pattern for opening an upper portion between adjacent photoelectric conversion portions 11 is formed by a lithography process, and then the resist pattern is baked, as shown in FIG. 9A.
  • a resist pattern (resist lens) 502a having a convex surface is formed.
  • an etching process such as RIE is performed.
  • the portion of the film 30 a that hits between the adjacent photoelectric conversion portions 11 is removed, and the optical waveguide 30 is formed in each hole 23 of the interlayer insulating film 20. be able to.
  • the convex shape is transferred to the surface of the film 30a by etching using the resist pattern as a mask. Thereby, the part formed in the optical waveguide 30 above the interlayer insulation film 20 can be made into a convex shape.
  • a planarizing film 40 and a color filter 50 are formed as shown in FIG. 9C, and finally, a microlens 60 is formed on the color filter 50 as shown in FIG. 9D. To do.
  • the solid-state imaging device 300 having the configuration shown in FIG. 8 can be manufactured.
  • the solid-state imaging device according to the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments. (1) The above embodiments and modifications may be combined.
  • the solid-state imaging device 200 according to the second embodiment and the solid-state imaging device 300 according to the third embodiment may be combined.
  • FIG. 10 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 400 in which the solid-state imaging device 200 according to the second embodiment and the solid-state imaging device 300 according to the third embodiment are combined. In the solid-state imaging device 400 shown in FIG.
  • a film 30c made of a material having a second refractive index is formed over the entire surface area of the interlayer insulating film 20 (that is, the portion 33 of the film 30c is adjacent to the film 30c).
  • Matching optical waveguides 30 are connected.
  • the raised portion of the optical waveguide 30 has a convex lens shape.
  • FIG. 11 is a partial cross-sectional view showing a configuration of a solid-state imaging device 500 in which the solid-state imaging device 201 of Modification 2-1 and the solid-state imaging device 300 of Embodiment 3 are combined.
  • a wiring protective film 91 is formed so as to cover all of the optical waveguides 30 formed in the recessed portions of the interlayer insulating film 20.
  • the raised portion of the optical waveguide 30 has a convex lens shape.
  • the entire surface of the interlayer insulating film 20 is covered with the material having the second refractive index, and the raised portion of the optical waveguide 30 has a convex lens shape. Therefore, the deterioration of the wiring layer 21 can be suppressed while increasing the light collection efficiency of the light incident on the optical waveguide 70 onto the photoelectric conversion unit 11.
  • two wiring layers are formed in the interlayer insulating film 20, but the wiring layer may be one layer or three or more layers.
  • the present invention can be widely applied to a solid-state imaging device having an optical waveguide.
  • Solid-state imaging device 100, 200, 201, 300, 400, 500 Solid-state imaging device 10
  • Semiconductor substrate 11
  • Photoelectric conversion unit 20
  • Interlayer insulating film 21
  • Wiring layer 30
  • Optical waveguide 40
  • Flattening film 50
  • Color filter 60
  • Lens 80
  • Cell 90, 91 Wiring protective film

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Solid State Image Pick-Up Elements (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
  • Color Television Image Signal Generators (AREA)

Abstract

A solid-state imaging device comprises: a semiconductor substrate (10) having a plurality of photoelectric conversion portions (11) formed in a matrix shape; an interlayer insulating film (20) formed on the semiconductor substrate (10) and having hole portions (23) formed at the portions corresponding to above the respective photoelectric conversion portions; a plurality of optical waveguides (30) burying the respective hole portions (23), having portions rising from the interlayer insulating film (20), and having a second refractive index higher than a first refractive index; and a planarizing film (40) formed above the optical waveguides (30) and between adjacent optical waveguides and having a third refractive index lower than the second refractive index.

Description

固体撮像装置とその製造方法Solid-state imaging device and manufacturing method thereof
　本発明は、光導波路を備えた固体撮像装置とその製造方法に関する。 The present invention relates to a solid-state imaging device including an optical waveguide and a manufacturing method thereof.
　この種の固体撮像装置は、デジタルカメラや携帯電話機等に用いられている。同装置の一般的な構成の一例について説明する。図１２は、特許文献１の固体撮像装置１１００の構成を示す部分断面図である。図１２に示すように、特許文献１の固体撮像装置１１００では、半導体基板（不図示）上に、シリコン酸化膜、ポリシリコン、および膜質の異なる三層のシリコンナイトライド層からなる受光部１ａと受光部１ａを覆うシリコン酸化膜１ｂとを有するセンサ部１が形成されている。センサ部１上には、酸化シリコン膜および窒化シリコン膜の積層体等からなる層間絶縁膜３が形成されており、この層間絶縁膜３内には、銅配線などからなる複数の配線層２（配線層２ａ、配線層２ｂ、および配線層２ｃ）が埋め込まれている。そして、配線層２ａと受光部１ａとがコンタクトプラグＶ１により、配線層２ａと配線層２ｂとがコンタクトプラグＶ２により、配線層２ｂと配線層２ｃとがコンタクトプラグＶ３により、それぞれ電気的に接続されている。 This type of solid-state imaging device is used in digital cameras and mobile phones. An example of a general configuration of the apparatus will be described. FIG. 12 is a partial cross-sectional view showing the configuration of the solid-state imaging device 1100 of Patent Document 1. As shown in FIG. 12, in the solid-state imaging device 1100 of Patent Document 1, a light receiving unit 1a including a silicon oxide film, polysilicon, and three silicon nitride layers having different film qualities on a semiconductor substrate (not shown) A sensor unit 1 having a silicon oxide film 1b covering the light receiving unit 1a is formed. An interlayer insulating film 3 made of a laminated body of a silicon oxide film and a silicon nitride film or the like is formed on the sensor unit 1, and in the interlayer insulating film 3, a plurality of wiring layers 2 ( The wiring layer 2a, the wiring layer 2b, and the wiring layer 2c) are embedded. The wiring layer 2a and the light receiving portion 1a are electrically connected by a contact plug V1, the wiring layer 2a and the wiring layer 2b are electrically connected by a contact plug V2, and the wiring layer 2b and the wiring layer 2c are electrically connected by a contact plug V3, respectively. ing.
　一方、層間絶縁膜３上には、保護膜４が形成されており、保護膜４上には、層間絶縁膜３を構成する材料の屈折率よりも高い屈折率のＴｉＯ分散型ポリイミド部５が形成されている。このＴｉＯ分散型ポリイミド部５は、一部が受光部１ａ方向に向かって伸びた構成となっている（以下、保護膜４の表面領域から受光部１ａ方向に向かって伸びた部分５ａを「光導波路」と記す。）。 On the other hand, a protective film 4 is formed on the interlayer insulating film 3, and a TiO dispersed polyimide portion 5 having a refractive index higher than the refractive index of the material constituting the interlayer insulating film 3 is formed on the protective film 4. Is formed. The TiO-dispersed polyimide portion 5 has a configuration in which a part extends toward the light receiving portion 1a (hereinafter, a portion 5a extending from the surface region of the protective film 4 toward the light receiving portion 1a is referred to as “light guide”. "Waveguide").
　さらに、ＴｉＯ分散型ポリイミド５上に、アクリル系熱硬化樹脂７を介して、カラーフィルタ８が形成され、カラーフィルタ８上にオンチップレンズ９が形成されている。 Further, a color filter 8 is formed on the TiO-dispersed polyimide 5 via an acrylic thermosetting resin 7, and an on-chip lens 9 is formed on the color filter 8.
特開２００６－２２２２７０号公報JP 2006-222270 A
　ところで、上記固体撮像装置１１００では、光導波路５ａの上方にオンチップレンズ９が形成されているため、このレンズ９に入射した光は、基本的には、光導波路５ａ内に集光され、当該光導波路５ａを通って受光部１ａに到達することになる。ただし、全ての光が光導波路５ａ内に集光されるわけではなく、一部の光は、光導波路５ａ内に入射せず、当該光導波路５ａからずれた領域（すなわち、保護膜４上面。）に向かう。そのとき、例えば保護膜４上面に対して斜めに入射した光が、隣り合う光導波路に混ざりこむ恐れがある（所謂、混色。）。保護膜４上には、ＴｉＯ分散型ポリイミド部５が存在するため、保護膜４上面に向けて斜めに入射した光が、保護膜４とアクリル系熱硬化樹脂７またはカラーフィルタ８底面との間を多重反射し、隣り合う光導波路の方向へ向かうためである。 By the way, in the solid-state imaging device 1100, since the on-chip lens 9 is formed above the optical waveguide 5a, the light incident on the lens 9 is basically condensed in the optical waveguide 5a. The light-receiving part 1a is reached through the optical waveguide 5a. However, not all of the light is collected in the optical waveguide 5a, and a part of the light does not enter the optical waveguide 5a and is shifted from the optical waveguide 5a (that is, the upper surface of the protective film 4). Head to). At this time, for example, light incident obliquely on the upper surface of the protective film 4 may be mixed into adjacent optical waveguides (so-called color mixing). Since the TiO-dispersed polyimide portion 5 is present on the protective film 4, light incident obliquely toward the upper surface of the protective film 4 is between the protective film 4 and the acrylic thermosetting resin 7 or the bottom surface of the color filter 8. Is reflected in the direction of the adjacent optical waveguide.
　そうすると、隣り合う光導波路に対応する受光部に到達する光量が、混ざりこんだ光の分だけ増加するため、正確に色を再現することが困難になり、画質の劣化を招いてしまう。 In this case, the amount of light reaching the light receiving unit corresponding to the adjacent optical waveguide is increased by the amount of mixed light, so that it is difficult to accurately reproduce the color and the image quality is deteriorated.
　本発明は、上記課題を解決するもので、混色による画質の劣化を抑制する固体撮像装置を提供するものである。 The present invention solves the above-described problems, and provides a solid-state imaging device that suppresses deterioration in image quality due to color mixing.
　上記課題を解決するために、本発明の一態様である固体撮像装置は、行列状に形成された複数の光電変換部を有する半導体基板と、前記半導体基板の上に形成され、前記複数の光電変換部それぞれの上方に当たる部分に穴部が形成された、第１の屈折率の層間絶縁膜と、各穴部内を埋め、かつ、前記層間絶縁膜よりも盛り上がった部分を有する、前記第１の屈折率より高い第２の屈折率の複数の光導波路と、前記複数の光導波路の上および隣り合う光導波路の間に形成された、前記第２の屈折率より低い第３の屈折率の平坦化膜とを備えることを特徴とする。 In order to solve the above problems, a solid-state imaging device which is one embodiment of the present invention includes a semiconductor substrate having a plurality of photoelectric conversion portions formed in a matrix and the plurality of photoelectric conversion devices formed on the semiconductor substrate. The first refractive index interlayer insulating film having a hole formed in a portion corresponding to the upper part of each conversion portion, and the first refractive index interlayer insulating film filling each hole and rising from the interlayer insulating film. A plurality of optical waveguides having a second refractive index higher than the refractive index, and a flat third having a third refractive index lower than the second refractive index, formed on the plurality of optical waveguides and between adjacent optical waveguides. And a chemical film.
　ここで、複数の光導波路の各々は、実質的に独立している。複数の光導波路の各々が実質的に独立しているとは、一の光導波路に入射した光が当該光導波路から隣り合う光導波路に伝播するための光路が、存在しないことである。したがって、図１，８に示すように、隣り合う光導波路３０の間が平坦化膜４０により埋められている場合はもちろん、光が伝播しない限りにおいて、図４，６，１０，１１に示すように、隣り合う光導波路３０の間に、第２の屈折率を有する材料からなる膜の一部（膜３０ｂの部分３３、配線保護膜９０）が存在し、当該膜の一部が両光導波路を繋いでいる場合も含む。 Here, each of the plurality of optical waveguides is substantially independent. The fact that each of the plurality of optical waveguides is substantially independent means that there is no optical path for light incident on one optical waveguide to propagate from the optical waveguide to an adjacent optical waveguide. Therefore, as shown in FIGS. 1, 8, as shown in FIGS. 4, 6, 10, and 11, as long as light is not propagated, as well as the space between adjacent optical waveguides 30 is filled with the planarizing film 40. In addition, between the adjacent optical waveguides 30, there is a part of the film (part 33 of the film 30 b, wiring protection film 90) made of a material having the second refractive index, and part of the film is part of both optical waveguides. Including the case of connecting
　なお、本明細書では、光導波路は、光の通路となる、所謂コア部のみを指している。 In the present specification, the optical waveguide refers only to a so-called core portion that serves as a light path.
　本発明の一態様に係る固体撮像装置には、層間絶縁膜の各穴部を埋め、かつ、当該層間絶縁膜よりも盛り上がった部分を有する複数の光導波路が存在し、これら複数の光導波路の上および隣り合う光導波路の間に平坦化膜が形成されている。したがって、一の光導波路に入射した光が、穴部内に向かわずに、隣り合う光導波路の方向へ向かったとしても、これら光導波路間に存在する平坦化膜で反射し、当該穴部内に集光されることになる。 In the solid-state imaging device according to one embodiment of the present invention, there are a plurality of optical waveguides that fill each hole portion of the interlayer insulating film and have a raised portion than the interlayer insulating film. A planarizing film is formed between the upper and adjacent optical waveguides. Therefore, even if the light incident on one optical waveguide does not go into the hole but goes in the direction of the adjacent optical waveguide, it is reflected by the planarizing film existing between the optical waveguides and collected in the hole. It will be lighted.
　よって、隣り合う光導波路に対応する光電変換部に混ざりこむ光量を低減することができるので、画質の劣化を抑制することができる。 Therefore, since the amount of light mixed in the photoelectric conversion unit corresponding to the adjacent optical waveguide can be reduced, deterioration in image quality can be suppressed.
　ここで、本発明の別の態様として、前記層間絶縁膜は、その内部に配線層を含み、前記複数の光導波路は前記複数の光電変換部に亘って連続的に形成されているとしてもよい。 Here, as another aspect of the present invention, the interlayer insulating film may include a wiring layer therein, and the plurality of optical waveguides may be continuously formed across the plurality of photoelectric conversion units. .
　この態様では、層間絶縁膜の表面全体が、前記第１および前記第３の屈折率より高い屈折率を有する材料により覆われることになる。これにより、層間絶縁膜に浸透する水分を抑制することができるので、層間絶縁膜内に存在する配線層の劣化を抑制することができる。 In this aspect, the entire surface of the interlayer insulating film is covered with a material having a higher refractive index than the first and third refractive indexes. Thereby, moisture that permeates the interlayer insulating film can be suppressed, so that deterioration of the wiring layer existing in the interlayer insulating film can be suppressed.
　また、本発明の別の態様として、前記複数の光導波路における、前記層間絶縁膜よりも盛り上がった部分が、レンズ形状であるとしてもよい。 As another aspect of the present invention, portions of the plurality of optical waveguides that are higher than the interlayer insulating film may have a lens shape.
　この態様では、光導波路自体にレンズと同様の集光能力を持たせることができる。 In this embodiment, the optical waveguide itself can have the same light collecting ability as the lens.
実施の形態１の固体撮像装置１００の構成を示す部分断面図である。1 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 100 according to Embodiment 1. FIG. 固体撮像装置１００の製造工程の一部分を示す図である。4 is a diagram illustrating a part of a manufacturing process of the solid-state imaging device 100. FIG. 固体撮像装置１００の製造工程のうち図２で示す部分に後続する部分を示す図である。FIG. 3 is a diagram illustrating a portion subsequent to the portion illustrated in FIG. 2 in the manufacturing process of the solid-state imaging device 100. 実施の形態２の固体撮像装置２００の構成を示す部分断面図である。6 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 200 according to Embodiment 2. FIG. 固体撮像装置２００の製造工程を示す図である。6 is a diagram illustrating a manufacturing process of the solid-state imaging device 200. FIG. 変形例２－１の固体撮像装置２０１の構成を示す部分断面図である。FIG. 10 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 201 of Modification 2-1. 固体撮像装置２０１の製造工程を示す図である。FIG. 11 is a diagram illustrating a manufacturing process of the solid-state imaging device 201. 実施の形態３の固体撮像装置３００の構成を示す部分断面図である。6 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 300 according to Embodiment 3. FIG. 固体撮像装置３００の製造工程を示す図である。6 is a diagram illustrating a manufacturing process of the solid-state imaging device 300. FIG. 固体撮像装置４００の構成を示す部分断面図である。2 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 400. FIG. 固体撮像装置５００の構成を示す部分断面図である。2 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 500. FIG. 特許文献１の固体撮像装置１１００の構成を示す部分断面図である。FIG. 11 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 1100 of Patent Document 1.
＜実施の形態１＞
１－１．固体撮像装置の構成
　－構成概略－
　図１は、実施の形態１の固体撮像装置１００の構成を示す部分断面図である。固体撮像装置１００は、図１に示すように、行列状に形成された複数の光電変換部１１を有する半導体基板１０と、半導体基板１０上に形成された層間絶縁膜２０と、層間絶縁膜２０上にセル８０毎に形成された光導波路３０と、光導波路３０および層間絶縁膜２０における、当該光導波路３０が形成されていない領域上に形成された平坦化膜４０と、平坦化膜４０上に形成され、有機材料に顔料が分散されてなるカラーフィルタ５０と、カラーフィルタ５０上に形成され、入射光を光電変換部１１に集光するマイクロレンズ６０とを備えている。 <Embodiment 1>
1-1. Configuration of solid-state imaging device-Outline of configuration-
FIG. 1 is a partial cross-sectional view illustrating the configuration of the solid-state imaging device 100 according to the first embodiment. As shown in FIG. 1, the solid-state imaging device 100 includes a semiconductor substrate 10 having a plurality of photoelectric conversion units 11 formed in a matrix, an interlayer insulating film 20 formed on the semiconductor substrate 10, and an interlayer insulating film 20. An optical waveguide 30 formed for each cell 80 on the top, a planarizing film 40 formed on a region of the optical waveguide 30 and the interlayer insulating film 20 where the optical waveguide 30 is not formed, and the planarizing film 40 The color filter 50 is formed by dispersing a pigment in an organic material, and the microlens 60 is formed on the color filter 50 and collects incident light on the photoelectric conversion unit 11.
　－各部構成－
　以下、固体撮像装置１００の構成について詳細に説明する。 -Configuration of each part-
Hereinafter, the configuration of the solid-state imaging device 100 will be described in detail.
　層間絶縁膜２０は、複数の膜が積層された積層体であり、各膜は後述する光導波路３０を構成する材料の屈折率より低い屈折率（以下、「第１の屈折率」とも記す。）の材料からなる。材料としては、例えば、酸化シリコン、窒化シリコン、および炭化シリコン等が挙げられる。層間絶縁膜２０は、表面領域において、光電変換部１１の上方に当たる部分２３が窪んでいる（以下、窪んでいる部分を「穴部」と記し、穴部２３とは反対に、山状になっている部分２４を「突出部」とも記す。）。一方、内部領域には、複数の配線層２１（配線層２１ａおよび配線層２１ｂ）が形成されており、これら配線層２１は、層間絶縁膜２０における、隣り合う光電変換部１１の間の上方に当たる部分（すなわち、突出部２４内）に位置している。光電変換部１１への光の入射を妨げないためである。 The interlayer insulating film 20 is a stacked body in which a plurality of films are stacked, and each film is also referred to as a refractive index lower than the refractive index of a material constituting the optical waveguide 30 described later (hereinafter also referred to as “first refractive index”). ) Material. Examples of the material include silicon oxide, silicon nitride, and silicon carbide. The interlayer insulating film 20 has a concave portion 23 in the surface region that is above the photoelectric conversion portion 11 (hereinafter, the concave portion is referred to as a “hole portion”, and has a mountain shape opposite to the hole portion 23. The portion 24 is also referred to as a “projection”.) On the other hand, a plurality of wiring layers 21 (wiring layer 21 a and wiring layer 21 b) are formed in the internal region, and these wiring layers 21 are located above the adjacent photoelectric conversion units 11 in the interlayer insulating film 20. It is located in the part (that is, in the protrusion 24). This is because the incident of light on the photoelectric conversion unit 11 is not hindered.
　光導波路３０は、透光性を有し、層間絶縁膜２０および後述する平坦化膜４０を構成する材料の屈折率より高い屈折率（以下、「第２の屈折率」とも記す。）の材料からなる。材料としては、例えば、ＴｉＯ分散ポリイミド等のＴｉＯを含む有機材料、または窒化シリコン等が挙げられる。光導波路３０は、層間絶縁膜２０の穴部２３内、および層間絶縁膜２０の上方に形成され、光導波路３０における、層間絶縁膜２０よりも上方に形成された部分（すなわち穴部２３からはみ出し盛り上がった部分）が、台錐形状になっている。また、ここでは、光導波路３０の一部が、突出部２４の端部上面に乗り上げた状態となっている。ただし、隣り合う光導波路３０同士は、層間絶縁膜２０の突出部２４上で接しておらず、互いに離れた位置に存在している。すなわち、光導波路３０の各々が独立した状態にある。 The optical waveguide 30 is translucent and has a higher refractive index (hereinafter also referred to as “second refractive index”) than the refractive index of the material constituting the interlayer insulating film 20 and the planarizing film 40 described later. Consists of. Examples of the material include organic materials containing TiO, such as TiO-dispersed polyimide, or silicon nitride. The optical waveguide 30 is formed in the hole 23 of the interlayer insulating film 20 and above the interlayer insulating film 20, and a portion of the optical waveguide 30 formed above the interlayer insulating film 20 (ie, protruding from the hole 23). The raised part has a trapezoidal shape. Here, a part of the optical waveguide 30 is in a state of riding on the upper surface of the end portion of the protruding portion 24. However, the adjacent optical waveguides 30 are not in contact with each other on the protruding portion 24 of the interlayer insulating film 20 and exist at positions separated from each other. That is, each of the optical waveguides 30 is in an independent state.
　平坦化膜４０は、層間絶縁膜２０と光導波路３０との表面段差を平坦に調整するために設けられ、光導波路３０を構成する材料の屈折率より低い屈折率（以下、「第３の屈折率」とも記す。）の材料からなる。材料としては、例えば、アクリル系熱硬化樹脂等が挙げられる。平坦化膜４０は、一部が隣り合う光導波路３０の間を埋めており、これにより、隣り合う光導波路３０が隔てられている（以下、平坦化膜４０において、隣り合う光導波路３０の間を埋める部分４１を「隔壁部」と記す。）。 The planarization film 40 is provided to adjust the surface step between the interlayer insulating film 20 and the optical waveguide 30 to be flat, and has a refractive index lower than the refractive index of the material constituting the optical waveguide 30 (hereinafter referred to as “third refraction”). It is also referred to as “rate”.) Examples of the material include acrylic thermosetting resins. The planarization film 40 partially fills the gap between the adjacent optical waveguides 30, thereby separating the adjacent optical waveguides 30 (hereinafter, between the adjacent optical waveguides 30 in the planarization film 40. The portion 41 that fills in is described as a “partition wall”.)
　このような構成において、層間絶縁膜２０および平坦化膜４０がクラッド部として機能している。このように、本実施の形態の固体撮像装置１００では、クラッド部が層間絶縁膜２０だけでなく、平坦化膜４０を含んで構成されている。言い換えると、隣り合う光導波路３０の間を埋めている平坦化膜４０の隔壁部４１の厚みの分だけ、クラッド部が積層方向に伸び、その結果、光導波路３０も積層方向に伸びた構成となっている。 In such a configuration, the interlayer insulating film 20 and the planarizing film 40 function as a cladding portion. As described above, in the solid-state imaging device 100 according to the present embodiment, the cladding portion includes not only the interlayer insulating film 20 but also the planarization film 40. In other words, the cladding portion extends in the stacking direction by the thickness of the partition wall portion 41 of the planarization film 40 filling between the adjacent optical waveguides 30. As a result, the optical waveguide 30 also extends in the stacking direction. It has become.
　したがって、図１に示すように、マイクロレンズ６０から光導波路３０内に入射した後、層間絶縁膜２０の穴部２３内に向かわずに、突出部２４上面の方向に向かう光Ｌ１は、平坦化膜４０の隔壁部４１により反射され、当該穴部２３内へ向かうことになる。光導波路３０が積層方向に伸びた分だけ、隣り合う光導波路３０に向かう光量が低減されるので、混色を抑制することができる。 Therefore, as shown in FIG. 1, after entering the optical waveguide 30 from the microlens 60, the light L1 directed toward the upper surface of the protrusion 24 without being directed into the hole 23 of the interlayer insulating film 20 is flattened. The light is reflected by the partition wall 41 of the film 40 and goes into the hole 23. Since the amount of light toward the adjacent optical waveguides 30 is reduced by the amount of the optical waveguides 30 extending in the stacking direction, color mixing can be suppressed.
　－層間絶縁膜２０、光導波路３０、および平坦化膜４０の位置関係－
　光導波路３０は、上述のように、一部が突出部２４の端部上面に乗り上げた状態となっている。ここで、光導波路３０の乗り上げた部分の端部と突出部２４上面とがなす内角ａｎｇ１は、直角に近いほど好ましい。内角ａｎｇ１が直角に近いほど、光導波路３０上面の幅が広くなるため、光導波路３０の領域が増し、より多くの光を光導波路３０内に集光することができるためである。 -Positional relationship between the interlayer insulating film 20, the optical waveguide 30, and the planarizing film 40-
As described above, a part of the optical waveguide 30 rides on the upper surface of the end portion of the protruding portion 24. Here, the inner angle ang1 formed by the end of the portion of the optical waveguide 30 that rides on and the upper surface of the protrusion 24 is preferably as close to a right angle as possible. This is because as the inner angle ang1 is closer to a right angle, the width of the upper surface of the optical waveguide 30 becomes wider, so that the area of the optical waveguide 30 increases and more light can be collected in the optical waveguide 30.
　また、１セル８０の幅ｗｉｄ１は、例えば１．４μｍであり、光導波路３０上面の幅ｗｉｄ２は、１．１～１．２μｍである。隣り合う光導波路３０の間における、最も幅広になっている部分の幅ｗｉｄ３は、後述する光染み出し量より広い範囲内で狭い方が好ましく、例えば１９１～３００ｎｍである。この幅が狭いほど、光導波路３０の領域が広くなり、より多くの光を光導波路３０内に集光することができるためである。 The width wid1 of one cell 80 is, for example, 1.4 μm, and the width wid2 of the upper surface of the optical waveguide 30 is 1.1 to 1.2 μm. The width wid3 of the widest portion between the adjacent optical waveguides 30 is preferably narrower within a wider range than the amount of light leakage described later, and is, for example, 191 to 300 nm. This is because the narrower the width is, the wider the region of the optical waveguide 30 is, and more light can be collected in the optical waveguide 30.
　また、光導波路３０における、層間絶縁膜２０よりも上方に形成された部分の厚みｔｈ１は、厚い方が好ましく、例えば２００～４００ｎｍである。逆に、平坦化膜４０における、光導波路３０の上面に位置する部分の膜厚ｔｈ２は、薄い方が好ましく、例えば１００ｎｍである。光導波路３０がマイクロレンズ６０に近づくことにより、当該レンズ６０から隣り合う光導波路３０に向かう光を減少させ、より一層混色を抑制することができるからである。 Further, the thickness th1 of the portion formed above the interlayer insulating film 20 in the optical waveguide 30 is preferably thicker, for example, 200 to 400 nm. On the contrary, the thickness th2 of the portion of the planarizing film 40 located on the upper surface of the optical waveguide 30 is preferably thinner, for example, 100 nm. This is because when the optical waveguide 30 approaches the microlens 60, light traveling from the lens 60 toward the adjacent optical waveguide 30 can be reduced, and color mixing can be further suppressed.
　－光染み出し量－
　光が光導波路３０内を伝播する際、当該光導波路３０の外側に染み出す。光導波路３０を伝播する光の染み出し量は、以下の数式１により導出される。 -Light oozing amount-
When light propagates through the optical waveguide 30, the light oozes out of the optical waveguide 30. The amount of light that propagates through the optical waveguide 30 is derived from Equation 1 below.
　Ｗｐ＝λ／（π・（Ｎｆ２－Ｎｓ２）０．５）・・・（数式１）
　ここで、Ｗｐは光染み出し量、λは真空中の光の波長、Ｎｆは光導波路３０の屈折率、Ｎｓはクラッド部である平坦化膜４０の屈折率である。光導波路３０を構成する材料が、例えば窒化シリコンである場合、Ｎｆは１．９であり、平坦化膜４０を構成する材料が、例えば芳香族系高分子やアクリル酸系樹脂である場合、Ｎｓは１．５である。そうすると、波長４００ｎｍの光の染み出し量は、およそ１０９ｎｍとなり、波長７００ｎｍの光の染み出し量は、およそ１９１ｎｍとなる。したがって、隣り合う光導波路３０の間の距離ｗｉｄ３を１９１ｎｍより大きく設定することで、一の光導波路３０内の光が、隣り合う光導波路３０内まで染み出すことなく、当該一の光導波路３０内を進行することになる。よって、より一層混色を抑制することができる。
１－２．固体撮像装置の製造方法
　続いて、固体撮像装置１００の製造方法について説明する。図２、３は、製造方法における各工程での固体撮像装置１００の構成を示す断面図である。 Wp = λ / (π · (Nf 2 −Ns 2 ) 0.5 ) (Formula 1)
Here, Wp is the amount of light leakage, λ is the wavelength of light in vacuum, Nf is the refractive index of the optical waveguide 30, and Ns is the refractive index of the planarizing film 40 that is the cladding. When the material constituting the optical waveguide 30 is, for example, silicon nitride, Nf is 1.9, and when the material constituting the planarizing film 40 is, for example, an aromatic polymer or an acrylic resin, Ns Is 1.5. Then, the amount of light with a wavelength of 400 nm oozes out to about 109 nm, and the amount of light with a wavelength of 700 nm oozes out to about 191 nm. Therefore, by setting the distance wid3 between the adjacent optical waveguides 30 to be larger than 191 nm, the light in one optical waveguide 30 does not ooze into the adjacent optical waveguides 30, and the inside of the one optical waveguide 30. Will proceed. Therefore, color mixing can be further suppressed.
1-2. Manufacturing Method of Solid-State Imaging Device Subsequently, a manufacturing method of the solid-state imaging device 100 will be described. 2 and 3 are cross-sectional views illustrating the configuration of the solid-state imaging device 100 at each step in the manufacturing method.
　まず、半導体基板１０内に複数の光電変換部１１を行列状に形成する。次に、半導体基板１０上に、第１屈折率材料膜として、複数の膜の積層体からなる積層体膜２０ａをＣＶＤ（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ）法などにより形成する。この際、ダマシン法により、積層体膜２０ａ内に複数の配線層２１を併せて形成する。より詳細には、まず、積層体膜２０ａを構成する積層体の１層中に、配線を形成するための溝をエッチングにより形成する。そして、溝の底面及び側面にシード層となるバリアメタル膜を形成する。その後、溝内部のバリアメタル膜上に電解めっきにより銅を堆積し、溝の外部に堆積した導電材料をＣＭＰ（Ｃｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ）により除去する。この工程を各配線層について行うことで、図２（ａ）に示すように、積層体膜２０ａに埋め込まれた複数の配線層を形成することができる。 First, a plurality of photoelectric conversion portions 11 are formed in a matrix in the semiconductor substrate 10. Next, on the semiconductor substrate 10, as a first refractive index material film, a laminate film 20a made of a laminate of a plurality of films is formed by a CVD (Chemical Vapor Deposition) method or the like. At this time, a plurality of wiring layers 21 are also formed in the multilayer film 20a by the damascene method. More specifically, first, a groove for forming a wiring is formed by etching in one layer of the laminate constituting the laminate film 20a. Then, a barrier metal film serving as a seed layer is formed on the bottom and side surfaces of the groove. Thereafter, copper is deposited on the barrier metal film inside the trench by electrolytic plating, and the conductive material deposited outside the trench is removed by CMP (Chemical Mechanical Polishing). By performing this process for each wiring layer, a plurality of wiring layers embedded in the stacked body film 20a can be formed as shown in FIG.
　次に、図２（ｂ）に示すように、例えば、リソグラフィ工程により、積層体膜２０ａにおける、光電変換部１１の上方に当たる部分を開口するためのレジストパターン５０１を形成する。その後、ＲＩＥ（反応性イオンエッチング）などで積層体膜２０ａをエッチングすることにより穴部２３を形成することで、積層体膜２０ａの表面領域に段差を形成する。これにより、図２（ｃ）に示すように、表面領域において、光電変換部１１の上方に当たる部分が窪んだ層間絶縁膜２０を形成することができる。このエッチングで形成される穴部の深さ２３ａは、例えば４００ｎｍ～６００ｎｍ程度とする。 Next, as shown in FIG. 2B, for example, a resist pattern 501 for opening a portion corresponding to the upper side of the photoelectric conversion unit 11 in the multilayer film 20a is formed by a lithography process. Thereafter, the hole 23 is formed by etching the stacked body film 20a by RIE (reactive ion etching) or the like, thereby forming a step in the surface region of the stacked body film 20a. Thereby, as shown in FIG. 2C, an interlayer insulating film 20 in which a portion corresponding to the upper side of the photoelectric conversion portion 11 is depressed in the surface region can be formed. The depth 23a of the hole formed by this etching is, for example, about 400 nm to 600 nm.
　次に、図２（ｄ）に示すように、層間絶縁膜２０上に、第２屈折率材料膜（第１の透明膜）として、当該層間絶縁膜２０を構成する材料の屈折率より高い屈折率の材料からなる光導波路材料膜３０ａを形成する。この光導波路材料膜３０ａは、当該光導波路材料膜３０ａの膜厚のばらつきを抑制するのに十分な厚みを有することが好ましい。具体的には、表面領域の全体が、突出部２４の上面２２よりも高くなっている。光導波路材料膜３０ａ形成後、例えば、ＣＭＰまたはエッチバック等により、当該光導波路材料膜３０ａを平坦化してもよい。 Next, as shown in FIG. 2D, a refractive index higher than the refractive index of the material constituting the interlayer insulating film 20 is formed on the interlayer insulating film 20 as a second refractive index material film (first transparent film). An optical waveguide material film 30a made of a material having a constant ratio is formed. The optical waveguide material film 30a preferably has a thickness sufficient to suppress variations in the film thickness of the optical waveguide material film 30a. Specifically, the entire surface region is higher than the upper surface 22 of the protrusion 24. After the optical waveguide material film 30a is formed, the optical waveguide material film 30a may be planarized by, for example, CMP or etch back.
　次に、図３（ａ）に示すように、例えば、光導波路材料膜３０ａにおける、隣り合う光電変換部１１の間の上方に当たる部分を開口するためのレジストパターン５０２をリソグラフィ工程により形成した後、ＲＩＥなどのエッチング処理を実施する。これにより、図３（ｂ）に示すように、光導波路材料膜３０ａにおける、隣り合う光電変換部１１の間の上方に当たる部分３２が除去され、層間絶縁膜２０の各穴部２３に、当該各穴部２３を埋め、かつ、層間絶縁膜２０よりも盛り上がった部分を有する光導波路３０を形成することができる。 Next, as shown in FIG. 3A, for example, after a resist pattern 502 for opening an upper portion between adjacent photoelectric conversion portions 11 in the optical waveguide material film 30a is formed by a lithography process, An etching process such as RIE is performed. As a result, as shown in FIG. 3B, the portion 32 of the optical waveguide material film 30 a that hits between the adjacent photoelectric conversion portions 11 is removed, and each hole portion 23 of the interlayer insulating film 20 has each of the holes 23. It is possible to form the optical waveguide 30 that fills the hole portion 23 and has a portion that is higher than the interlayer insulating film 20.
　次に、図３（ｃ）に示すように、層間絶縁膜２０と光導波路３０との表面段差を平坦に調整するために、平坦化膜４０を形成し、当該平坦化膜４０上にカラーフィルタ５０を形成する。 Next, as shown in FIG. 3C, in order to adjust the surface step between the interlayer insulating film 20 and the optical waveguide 30 to be flat, a flattening film 40 is formed, and a color filter is formed on the flattening film 40. 50 is formed.
　最後に、図３（ｄ）に示すように、カラーフィルタ５０上にマイクロレンズ６０を形成する。 Finally, a microlens 60 is formed on the color filter 50 as shown in FIG.
　以上で、図１に示す構成の固体撮像装置１００を製造することができる。
＜実施の形態２＞
　実施の形態１の固体撮像装置１００では、隣り合う光導波路３０同士は、層間絶縁膜２０の突出部２４上で接しておらず、互いに離れた位置に存在していた。そのため、層間絶縁膜２０の表面領域上には、第２の屈折率の材料からなる領域が形成されていな部分が存在した。そうすると、第２の屈折率の材料で覆われずに当該材料から露出した領域から水分が浸透し、この水分により配線層２１の劣化が早まる可能性がある。 As described above, the solid-state imaging device 100 having the configuration shown in FIG. 1 can be manufactured.
<Embodiment 2>
In the solid-state imaging device 100 according to the first embodiment, the adjacent optical waveguides 30 are not in contact with each other on the protruding portion 24 of the interlayer insulating film 20 and exist at positions separated from each other. Therefore, on the surface region of the interlayer insulating film 20, there was a portion where a region made of the material having the second refractive index was not formed. Then, moisture may permeate from a region exposed from the material without being covered with the second refractive index material, and the moisture may accelerate deterioration of the wiring layer 21.
　本実施の形態では、混色の抑制に加え、水分による配線層２１の劣化も抑制する固体撮像装置について説明する。
２－１．固体撮像装置の構成
　図４は、実施の形態２の固体撮像装置２００の構成を示す部分断面図である。図４に示すように、本実施の形態の固体撮像装置２００は、層間絶縁膜２０の表面領域の全体が第２の屈折率を有する材料からなる膜３０ｂにより覆われている点が異なる以外は、基本的に実施の形態１の固体撮像装置１００と同様の構成をしている。したがって、図４において、実施の形態１に係る固体撮像装置１００と同様の構成部分の説明は省略し、以下では異なる部分を中心に説明する。 In the present embodiment, a solid-state imaging device that suppresses deterioration of the wiring layer 21 due to moisture in addition to suppression of color mixing will be described.
2-1. Configuration of Solid-State Imaging Device FIG. 4 is a partial cross-sectional view showing the configuration of the solid-state imaging device 200 according to the second embodiment. As shown in FIG. 4, the solid-state imaging device 200 of the present embodiment is different except that the entire surface region of the interlayer insulating film 20 is covered with a film 30b made of a material having a second refractive index. Basically, the configuration is the same as that of the solid-state imaging device 100 of the first embodiment. Therefore, in FIG. 4, the description of the same components as those of the solid-state imaging device 100 according to the first embodiment will be omitted, and the following description will focus on the different portions.
　上述のように、固体撮像装置２００では、層間絶縁膜２０の表面領域上に、第２の屈折率を有する材料からなる膜３０ｂが全体に亘って形成されている。 As described above, in the solid-state imaging device 200, the film 30b made of the material having the second refractive index is formed over the entire surface region of the interlayer insulating film 20.
　ここで、第２の屈折率を有する材料は、第１および第３の屈折率を有する材料よりも高い屈折率を有するため、膜３０ｂはこれらの材料からなる膜より緻密であり、水分に対するバリア性が高い。このような膜３０ｂが層間絶縁膜２０の表面領域の全体に亘って形成されているので、層間絶縁膜２０に浸透する水分を低減することができ、層間絶縁膜２０内に存在する配線層２１の水分による劣化を抑制することができる。 Here, since the material having the second refractive index has a higher refractive index than the materials having the first and third refractive indexes, the film 30b is denser than the film made of these materials and has a barrier against moisture. High nature. Since such a film 30b is formed over the entire surface region of the interlayer insulating film 20, moisture penetrating into the interlayer insulating film 20 can be reduced, and the wiring layer 21 existing in the interlayer insulating film 20 can be reduced. Deterioration due to moisture can be suppressed.
　また、固体撮像装置２００では、膜３０ｂの一部、すなわち光電変換部１１の上方に当たる部分の各々が、光導波路３０を形成している。そして、膜３０ｂのうち、光導波路３０における、層間絶縁膜２０の窪んでいる部分からはみ出した部分の膜厚ｔｈ１が、光導波路３０を形成する部分以外の部分３３（以下、単に「部分」と記す。）の膜厚ｔｈ３よりも厚くなっている。この部分３３の膜厚ｔｈ３の制限について説明する。光学的な観点から見ると、部分３３の膜厚ｔｈ３は、光を伝播しない厚さである必要がある。当該部分３３を通じて、隣り合う光導波路３０に光を伝播させないためである。 Further, in the solid-state imaging device 200, a part of the film 30b, that is, each of the parts that contact the photoelectric conversion unit 11 forms the optical waveguide 30. Of the film 30b, the thickness th1 of the portion of the optical waveguide 30 that protrudes from the recessed portion of the interlayer insulating film 20 is a portion 33 (hereinafter simply referred to as “part”) other than the portion that forms the optical waveguide 30. It is thicker than the film thickness th3. The limitation on the film thickness th3 of the portion 33 will be described. From an optical viewpoint, the thickness th3 of the portion 33 needs to be a thickness that does not propagate light. This is because light is not propagated to the adjacent optical waveguide 30 through the portion 33.
　一方、配線層２１の劣化を抑制するという観点から見ると、膜３０ｂにおける部分３３は、厚いほうが好ましい。水分に対するバリア性を向上させることができるからである。 On the other hand, from the viewpoint of suppressing the deterioration of the wiring layer 21, the portion 33 in the film 30b is preferably thick. This is because the barrier property against moisture can be improved.
　これらを踏まえ、部分３３の膜厚ｔｈ３を、光を伝播しない範囲内で最も厚くすることにより、水分に対するバリア性を最大限に高めつつ、混色を抑制することができる。具体的には、部分３３の厚みｔｈ３は、数ｎｍ以上、数十ｎｍ以下の範囲が好ましい。ここで、可視光の波長は、およそ４００ｎｍ～８００ｎｍ程度であるため、部分３３の厚みｔｈ３を仮に５０ｎｍとすると、可視光のどの波長に対しても、その膜厚は、波長の８分の１以下となる。これは、可視光の波長に対して十分に薄いため、光学的な劣化が生じることなく、十分に混色防止効果を得ることができると考えられる。また、水分による配線層２１の劣化も抑制することができる。 Based on these considerations, by making the thickness th3 of the portion 33 the thickest within the range where light does not propagate, color mixing can be suppressed while maximizing the barrier property against moisture. Specifically, the thickness th3 of the portion 33 is preferably in the range of several nm to several tens of nm. Here, since the wavelength of visible light is about 400 nm to about 800 nm, assuming that the thickness th3 of the portion 33 is 50 nm, the film thickness is 1/8 of the wavelength for any wavelength of visible light. It becomes as follows. Since this is sufficiently thin with respect to the wavelength of visible light, it is considered that a color mixing prevention effect can be sufficiently obtained without causing optical degradation. Moreover, deterioration of the wiring layer 21 due to moisture can be suppressed.
　以上のように本実施の形態の固体撮像装置２００では、混色を抑制しつつ、水分による配線層２１の劣化を防止することができる。
２－２．固体撮像装置の製造方法
　続いて、固体撮像装置２００の製造方法について説明する。図５は、製造方法における各工程での固体撮像装置２００の構成を示す断面図である。 As described above, in the solid-state imaging device 200 of the present embodiment, it is possible to prevent deterioration of the wiring layer 21 due to moisture while suppressing color mixing.
2-2. Next, a manufacturing method of the solid-state imaging device 200 will be described. FIG. 5 is a cross-sectional view showing the configuration of the solid-state imaging device 200 at each step in the manufacturing method.
　実施の形態１の図３（ａ）で示す工程までは、実施の形態１で説明したものと同様であるので、ここでは、それ以降の工程について説明する。 Since the steps shown in FIG. 3A of the first embodiment are the same as those described in the first embodiment, the subsequent steps will be described here.
　膜３０ａにおいて、隣り合う光電変換部１１の間の上方に当たる部分を開口するためのレジストパターン５０２を、リソグラフィ工程により形成した後、ＲＩＥなどのエッチング処理を実施する。ただし、この際、エッチングレートを調節し、層間絶縁膜２０における、隣り合う光電変換部１１の間の上方に当たる部分の表面に、膜３０ａの一部を残存させる。これにより、図５（ａ）に示すように、層間絶縁膜２０の表面領域の全体に亘って、第２の屈折率を有する材料からなる膜３０ｂを形成することができる。 In the film 30a, a resist pattern 502 for opening an upper portion between adjacent photoelectric conversion portions 11 is formed by a lithography process, and then an etching process such as RIE is performed. However, at this time, the etching rate is adjusted, and a part of the film 30a is left on the surface of the portion of the interlayer insulating film 20 that is located between the adjacent photoelectric conversion portions 11. Thereby, as shown in FIG. 5A, a film 30 b made of a material having the second refractive index can be formed over the entire surface region of the interlayer insulating film 20.
　また、膜３０ｂの部分３３は、光導波路３０と同一の材料から構成され、光導波路３０と同一工程で形成される。そのため、膜３０ｂの部分３３の形成に伴う工程数の増加を抑制することができる。したがって、別途工程を追加することなく、配線層２１の劣化を抑制することができる。 Further, the portion 33 of the film 30 b is made of the same material as the optical waveguide 30 and is formed in the same process as the optical waveguide 30. Therefore, an increase in the number of steps accompanying the formation of the portion 33 of the film 30b can be suppressed. Therefore, the deterioration of the wiring layer 21 can be suppressed without adding a separate process.
　次に、図５（ｂ）に示すように、膜３０ｂの表面段差を平坦に調整するために、平坦化膜４０を形成し、当該平坦化膜４０上にカラーフィルタ５０を形成する。 Next, as shown in FIG. 5B, in order to adjust the surface step of the film 30b to be flat, the flattening film 40 is formed, and the color filter 50 is formed on the flattening film 40.
　最後に、図５（ｃ）に示すように、カラーフィルタ５０上にマイクロレンズ６０を形成する。 Finally, as shown in FIG. 5C, the micro lens 60 is formed on the color filter 50.
　以上で、図４に示す構成の固体撮像装置２００を製造することができる。
＜変形例２－１＞
　配線保護膜を備えた一変形例について説明する。
２－１－１．固体撮像装置の構成
　図６は、変形例２－１の固体撮像装置２０１の構成を示す部分断面図である。図６に示すように、本実施の形態の固体撮像装置２０１は、配線保護膜９０を備える点が異なる以外は、基本的に実施の形態１の固体撮像装置１００と同様の構成をしている。したがって、図６において、実施の形態１に係る固体撮像装置１００と同様の構成部分の説明は省略し、以下では異なる部分を中心に説明する。 As described above, the solid-state imaging device 200 having the configuration shown in FIG. 4 can be manufactured.
<Modification 2-1>
A modified example including a wiring protective film will be described.
2-1-1. Configuration of Solid-State Imaging Device FIG. 6 is a partial cross-sectional view showing the configuration of the solid-state imaging device 201 of Modification 2-1. As shown in FIG. 6, the solid-state imaging device 201 of the present embodiment has basically the same configuration as that of the solid-state imaging device 100 of the first embodiment except that a wiring protective film 90 is provided. . Therefore, in FIG. 6, the description of the same components as those of the solid-state imaging device 100 according to Embodiment 1 will be omitted, and the following description will focus on the different portions.
　配線保護膜９０は、層間絶縁膜２０の各穴部２３に形成された光導波路３０の全てを覆うように形成され、光導波路３０と同様、第２の屈折率を有する材料からなる。すなわち、層間絶縁膜２０の表面全体が、第２の屈折率を有する材料からなる配線保護膜９０で覆われている。また、配線保護膜９０は、光導波路３０に沿って形成されているため、表面領域に段差が存在し、この表面段差を平坦に調整するために、平坦化膜４０が形成されている。 The wiring protective film 90 is formed so as to cover all the optical waveguides 30 formed in the respective holes 23 of the interlayer insulating film 20, and is made of a material having a second refractive index, like the optical waveguide 30. That is, the entire surface of the interlayer insulating film 20 is covered with the wiring protective film 90 made of a material having the second refractive index. Further, since the wiring protective film 90 is formed along the optical waveguide 30, there is a step in the surface region, and the planarizing film 40 is formed in order to adjust the surface step to be flat.
　配線保護膜９０における、隣り合う光導波路３０間の部分の厚みの制限については、膜３０ｂの部分３３と同様であるので、ここでは説明を省略する。 The limitation on the thickness of the portion between the adjacent optical waveguides 30 in the wiring protective film 90 is the same as that of the portion 33 of the film 30b, and thus the description thereof is omitted here.
　このような構成でも、配線保護膜９０における、隣り合う光導波路３０間の部分の厚みを制限することにより、混色を抑制しつつ、水分による配線層２１の劣化を防止することができる。 Even in such a configuration, by limiting the thickness of the portion between the adjacent optical waveguides 30 in the wiring protective film 90, deterioration of the wiring layer 21 due to moisture can be prevented while suppressing color mixing.
　なお、ここでは、配線保護膜９０は、第２の屈折率を有する材料からなるとしたが、第１および第３の屈折率より高い屈折率を有する材料であればよい。
２－１－２．固体撮像装置の製造方法
　続いて、固体撮像装置２０１の製造方法について説明する。図７は、製造方法における各工程での固体撮像装置２０１の構成を示す断面図である。 Here, the wiring protective film 90 is made of a material having the second refractive index, but any material having a refractive index higher than the first and third refractive indexes may be used.
2-1-2. Next, a method for manufacturing the solid-state imaging device 201 will be described. FIG. 7 is a cross-sectional view illustrating the configuration of the solid-state imaging device 201 at each step in the manufacturing method.
　実施の形態１の図３（ｂ）で示す工程までは、実施の形態１で説明したものと同様であるので、ここでは、それ以降の工程について説明する。 Since the steps shown in FIG. 3B of the first embodiment are the same as those described in the first embodiment, the subsequent steps will be described here.
　膜３０ａに対しＲＩＥなどのエッチング処理を実施した後、図７（ａ）に示すように、光導波路３０と同様の材料からなる配線保護膜９０を全体に亘って形成する。 After performing an etching process such as RIE on the film 30a, a wiring protective film 90 made of the same material as that of the optical waveguide 30 is formed over the entire surface, as shown in FIG.
　配線層２１の劣化を防止するための配線保護膜９０を別途形成することで、エッチングによる光導波路３０間の膜厚のばらつきを低減することができる。膜３０ａをエッチングする際、膜材料が異なる位置、すなわち層間絶縁膜２０の突出部２４上面２２が露出した段階でエッチング処理を停止すればよいので、エッチングの停止を精度よく行うことができるためである。これにより、配線層２１の劣化を抑制しつつ、セル間の光学特性の差も抑制することができる。 By separately forming the wiring protective film 90 for preventing the deterioration of the wiring layer 21, the variation in the film thickness between the optical waveguides 30 due to etching can be reduced. When etching the film 30a, the etching process may be stopped at a position where the film material is different, that is, when the upper surface 22 of the protruding portion 24 of the interlayer insulating film 20 is exposed, so that the etching can be stopped with high accuracy. is there. Thereby, the difference of the optical characteristic between cells can also be suppressed, suppressing deterioration of the wiring layer 21. FIG.
　配線保護膜９０を形成した後、図７（ｂ）に示すように、平坦化膜４０、カラーフィルタ５０、およびマイクロレンズ６０を形成する。 After forming the wiring protective film 90, as shown in FIG. 7B, the planarizing film 40, the color filter 50, and the microlens 60 are formed.
　以上で、図６に示す構成の固体撮像装置２０１を製造することができる。
＜実施の形態３＞
３－１．固体撮像装置の構成
　図８は、実施の形態３の固体撮像装置３００の構成を示す部分断面図である。図８に示すように、本実施の形態の固体撮像装置３００は、光導波路３０における、層間絶縁膜２０よりも上方に形成された部分の形状が異なる以外は、基本的に実施の形態１の固体撮像装置１００と同様の構成をしている。したがって、図８において、実施の形態１に係る固体撮像装置１００と同様の構成部分の説明は省略し、以下では異なる部分を中心に説明する。 As described above, the solid-state imaging device 201 having the configuration shown in FIG. 6 can be manufactured.
<Embodiment 3>
3-1. Configuration of Solid-State Imaging Device FIG. 8 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 300 according to the third embodiment. As shown in FIG. 8, the solid-state imaging device 300 of the present embodiment is basically the same as that of the first embodiment except that the shape of the portion formed above the interlayer insulating film 20 in the optical waveguide 30 is different. The configuration is the same as that of the solid-state imaging device 100. Therefore, in FIG. 8, the description of the same components as those of the solid-state imaging device 100 according to the first embodiment will be omitted, and the following description will focus on the different portions.
　本実施の形態の光導波路３０は、層間絶縁膜２０よりも上方に形成された部分３４の形状が凸レンズ状になっている。これにより、光導波路３０自体にもレンズと同様の集光能力を持たせることができるので、光導波路３０に入射した光を、より垂直方向に導くことができる。
３－２．固体撮像装置の製造方法
　続いて、固体撮像装置３００の製造方法について説明する。図９は、製造方法における各工程での固体撮像装置３００の構成を示す断面図である。 In the optical waveguide 30 of the present embodiment, the shape of the portion 34 formed above the interlayer insulating film 20 is a convex lens shape. Thereby, since the optical waveguide 30 itself can have the same light collecting ability as that of the lens, the light incident on the optical waveguide 30 can be guided in a more vertical direction.
3-2. Manufacturing Method of Solid-State Imaging Device Subsequently, a manufacturing method of the solid-state imaging device 300 will be described. FIG. 9 is a cross-sectional view showing the configuration of the solid-state imaging device 300 at each step in the manufacturing method.
　実施の形態１の図３（ａ）で示す工程までは、実施の形態１で説明したものと同様であるので、ここでは、それ以降の工程について説明する。 Since the steps shown in FIG. 3A of the first embodiment are the same as those described in the first embodiment, the subsequent steps will be described here.
　膜３０ａにおいて、隣り合う光電変換部１１の間の上方に当たる部分を開口するためのレジストパターンを、リソグラフィ工程により形成した後、当該レジストパターンをベークすることにより、図９（ａ）に示すように、表面が凸形状のレジストパターン（レジストレンズ）５０２ａを形成する。 In the film 30a, a resist pattern for opening an upper portion between adjacent photoelectric conversion portions 11 is formed by a lithography process, and then the resist pattern is baked, as shown in FIG. 9A. A resist pattern (resist lens) 502a having a convex surface is formed.
　次に、ＲＩＥなどのエッチング処理を実施する。これにより、図９（ｂ）に示すように、膜３０ａにおける、隣り合う光電変換部１１の間の上方に当たる部分が除去され、層間絶縁膜２０の各穴部２３に、光導波路３０を形成することができる。このとき、レジストパターンの表面が凸形状であるため、当該レジストパターンをマスクとしてエッチングすることで、膜３０ａの表面に凸形状が転写される。これにより、光導波路３０における、層間絶縁膜２０よりも上方に形成された部分を凸形状にすることができる。 Next, an etching process such as RIE is performed. As a result, as shown in FIG. 9B, the portion of the film 30 a that hits between the adjacent photoelectric conversion portions 11 is removed, and the optical waveguide 30 is formed in each hole 23 of the interlayer insulating film 20. be able to. At this time, since the surface of the resist pattern has a convex shape, the convex shape is transferred to the surface of the film 30a by etching using the resist pattern as a mask. Thereby, the part formed in the optical waveguide 30 above the interlayer insulation film 20 can be made into a convex shape.
　エッチング処理後、図９（ｃ）に示すように、平坦化膜４０、およびカラーフィルタ５０を形成し、最後に、図９（ｄ）に示すように、カラーフィルタ５０上にマイクロレンズ６０を形成する。 After the etching process, a planarizing film 40 and a color filter 50 are formed as shown in FIG. 9C, and finally, a microlens 60 is formed on the color filter 50 as shown in FIG. 9D. To do.
　以上で、図８に示す構成の固体撮像装置３００を製造することができる。
＜その他の変形例＞
　以上、本発明に係る固体撮像装置について、実施の形態に基づいて説明したが、本発明は、上記実施の形態に限られないことは勿論である。
（１）上記実施の形態及び変形例を組み合わせるとしてもよい。例えば、実施の形態２の固体撮像装置２００と実施の形態３の固体撮像装置３００とを組み合わせてもよい。図１０は、実施の形態２の固体撮像装置２００と実施の形態３の固体撮像装置３００とを組み合わせた固体撮像装置４００の構成を示す部分断面図である。図１０に示す固体撮像装置４００では、層間絶縁膜２０の表面領域上に、第２の屈折率を有する材料からなる膜３０ｃが全体に亘って形成されている（すなわち膜３０ｃの部分３３が隣り合う光導波路３０を繋いでいる。）。加えて、光導波路３０の盛り上がった部分の形状が凸レンズ状になっている。 As described above, the solid-state imaging device 300 having the configuration shown in FIG. 8 can be manufactured.
<Other variations>
As described above, the solid-state imaging device according to the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments.
(1) The above embodiments and modifications may be combined. For example, the solid-state imaging device 200 according to the second embodiment and the solid-state imaging device 300 according to the third embodiment may be combined. FIG. 10 is a partial cross-sectional view illustrating a configuration of a solid-state imaging device 400 in which the solid-state imaging device 200 according to the second embodiment and the solid-state imaging device 300 according to the third embodiment are combined. In the solid-state imaging device 400 shown in FIG. 10, a film 30c made of a material having a second refractive index is formed over the entire surface area of the interlayer insulating film 20 (that is, the portion 33 of the film 30c is adjacent to the film 30c). Matching optical waveguides 30 are connected.) In addition, the raised portion of the optical waveguide 30 has a convex lens shape.
　また、変形例２－１の固体撮像装置２０１と実施の形態３の固体撮像装置３００とを組み合わせてもよい。図１１は、変形例２－１の固体撮像装置２０１と実施の形態３の固体撮像装置３００とを組み合わせた固体撮像装置５００の構成を示す部分断面図である。図１１に示す固体撮像装置５００では、層間絶縁膜２０の窪んでいる各部分に形成された光導波路３０の全てを覆うように、配線保護膜９１が形成されている。加えて、光導波路３０の盛り上がった部分の形状が凸レンズ状になっている。 Further, the solid-state imaging device 201 of the modified example 2-1 and the solid-state imaging device 300 of the third embodiment may be combined. FIG. 11 is a partial cross-sectional view showing a configuration of a solid-state imaging device 500 in which the solid-state imaging device 201 of Modification 2-1 and the solid-state imaging device 300 of Embodiment 3 are combined. In the solid-state imaging device 500 shown in FIG. 11, a wiring protective film 91 is formed so as to cover all of the optical waveguides 30 formed in the recessed portions of the interlayer insulating film 20. In addition, the raised portion of the optical waveguide 30 has a convex lens shape.
　このように、固体撮像装置４００，５００では、層間絶縁膜２０の表面全体が第２の屈折率を有する材料で覆われ、かつ、光導波路３０の盛り上がった部分の形状が凸レンズ状になっているので、光導波路７０に入射した光の光電変換部１１への集光効率を高めつつ、配線層２１の劣化を抑制することができる。
（２）上記実施の形態等では、層間絶縁膜２０内に２層の配線層が形成されていたが、配線層は１層でもよいし、３層以上であってもよい。 As described above, in the solid- state imaging devices 400 and 500, the entire surface of the interlayer insulating film 20 is covered with the material having the second refractive index, and the raised portion of the optical waveguide 30 has a convex lens shape. Therefore, the deterioration of the wiring layer 21 can be suppressed while increasing the light collection efficiency of the light incident on the optical waveguide 70 onto the photoelectric conversion unit 11.
(2) In the above embodiment and the like, two wiring layers are formed in the interlayer insulating film 20, but the wiring layer may be one layer or three or more layers.
　本発明は、光導波路を備えた固体撮像装置に広く適用可能である。 The present invention can be widely applied to a solid-state imaging device having an optical waveguide.
１００，２００，２０１，３００，４００，５００　固体撮像装置
１０　半導体基板
１１　光電変換部
２０　層間絶縁膜
２１　配線層
３０　光導波路
４０　平坦化膜
５０　カラーフィルタ
６０　レンズ
８０　セル
９０，９１　配線保護膜 100, 200, 201, 300, 400, 500 Solid-state imaging device 10 Semiconductor substrate 11 Photoelectric conversion unit 20 Interlayer insulating film 21 Wiring layer 30 Optical waveguide 40 Flattening film 50 Color filter 60 Lens 80 Cell 90, 91 Wiring protective film

Claims (7)

  1. 　行列状に形成された複数の光電変換部を有する半導体基板と、
    　前記半導体基板の上に形成され、前記複数の光電変換部それぞれの上方に当たる部分に穴部が形成された、第１の屈折率の層間絶縁膜と、
    　各穴部内を埋め、かつ、前記層間絶縁膜よりも盛り上がった部分を有する、前記第１の屈折率より高い第２の屈折率の複数の光導波路と、
    　前記複数の光導波路の上および隣り合う光導波路の間に形成された、前記第２の屈折率より低い第３の屈折率の平坦化膜とを備える
    　ことを特徴とする固体撮像装置。     A semiconductor substrate having a plurality of photoelectric conversion portions formed in a matrix;
    An interlayer insulating film having a first refractive index, formed on the semiconductor substrate, and having a hole formed in a portion of the plurality of photoelectric conversion units that is in contact with each other;
    A plurality of optical waveguides having a second refractive index higher than the first refractive index, each of which fills each hole and has a portion raised from the interlayer insulating film;
    A solid-state imaging device comprising: a planarizing film having a third refractive index lower than the second refractive index formed on the plurality of optical waveguides and between adjacent optical waveguides.
  2. 　前記層間絶縁膜は、その内部に配線層を含み、
    　前記複数の光導波路は前記複数の光電変換部に亘って連続的に形成されている
    　ことを特徴とする請求項１に記載の固体撮像装置。     The interlayer insulating film includes a wiring layer therein,
    The solid-state imaging device according to claim 1, wherein the plurality of optical waveguides are continuously formed across the plurality of photoelectric conversion units.
  3. 　前記複数の光導波路は、各々独立に形成されている
    　ことを特徴とする請求項１に記載の固体撮像装置。     The solid-state imaging device according to claim 1, wherein each of the plurality of optical waveguides is formed independently.
  4. 　前記複数の光導波路における、前記層間絶縁膜よりも盛り上がった部分が、レンズ形状である
    　ことを特徴とする請求項１～３のいずれかに記載の固体撮像装置。     The solid-state imaging device according to any one of claims 1 to 3, wherein a portion of the plurality of optical waveguides that is raised from the interlayer insulating film has a lens shape.
  5. 　半導体基板に行列状に複数の光電変換部を形成する工程と、
    　前記半導体基板の上に第１の屈折率の第１屈折率材料膜を形成する工程と、
    　前記第１屈折率材料膜における、前記複数の光電変換部それぞれの上方に当たる部分に穴部を形成することで、層間絶縁膜を形成する工程と、
    　前記層間絶縁膜の上に、前記第１の屈折率より高い第２の屈折率の第１の透明膜を形成する工程と、
    　前記複数の光電変換部の各々に凸部が形成されるように、前記層間絶縁膜の上方に位置する第１の透明膜をエッチングし、複数の光導波路を形成する工程と、
    　前記複数の光導波路の上および隣り合う光導波路の間に、前記第２の屈折率より低い第３の屈折率の平坦化膜を形成する工程とを備える
    　ことを特徴とする固体撮像装置の製造方法。     Forming a plurality of photoelectric conversion portions in a matrix on a semiconductor substrate;
    Forming a first refractive index material film having a first refractive index on the semiconductor substrate;
    A step of forming an interlayer insulating film by forming a hole in a portion of the first refractive index material film that is above each of the plurality of photoelectric conversion portions;
    Forming a first transparent film having a second refractive index higher than the first refractive index on the interlayer insulating film;
    Etching the first transparent film located above the interlayer insulating film so that a convex portion is formed in each of the plurality of photoelectric conversion portions, and forming a plurality of optical waveguides;
    Forming a planarization film having a third refractive index lower than the second refractive index on the plurality of optical waveguides and between adjacent optical waveguides. Method.
  6. 　前記複数の光導波路を形成する工程では、
    　前記第１の透明膜の上にレジストレンズを形成する工程と、
    　前記レジストレンズをマスクとして前記第１の透明膜をエッチングして、前記レジストレンズの形状を前記第１の透明膜に転写する工程とを含む
    　ことを特徴とする請求項５に記載の固体撮像装置の製造方法。     In the step of forming the plurality of optical waveguides,
    Forming a resist lens on the first transparent film;
    The solid-state imaging device according to claim 5, further comprising: etching the first transparent film using the resist lens as a mask, and transferring the shape of the resist lens to the first transparent film. Manufacturing method.
  7. 　前記複数の光導波路を形成する工程の後であって、
    　前記平坦化膜を形成する工程の前に、
    　前記第１の透明膜の上に、第４の屈折率の第２の透明膜を形成する工程をさらに備え、
    　前記第４の屈折率は前記第１の屈折率および前記第３の屈折率よりも大きい
    　ことを特徴とする請求項５または６に記載の固体撮像装置の製造方法。     After the step of forming the plurality of optical waveguides,
    Before the step of forming the planarizing film,
    Forming a second transparent film having a fourth refractive index on the first transparent film;
    The method for manufacturing a solid-state imaging device according to claim 5 or 6, wherein the fourth refractive index is larger than the first refractive index and the third refractive index.
PCT/JP2011/002522 2010-11-22 2011-04-28 Solid-state imaging device and method for fabricating same WO2012070165A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010260254A JP2012114155A (en) 2010-11-22 2010-11-22 Solid-state imaging device and method of manufacturing the same
JP2010-260254 2010-11-22

Publications (1)

Publication Number Publication Date
WO2012070165A1 true WO2012070165A1 (en) 2012-05-31

Family

ID=46145539

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2011/002522 WO2012070165A1 (en) 2010-11-22 2011-04-28 Solid-state imaging device and method for fabricating same

Country Status (2)

Country Link
JP (1) JP2012114155A (en)
WO (1) WO2012070165A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013035258A1 (en) * 2011-09-06 2013-03-14 パナソニック株式会社 Solid-state image capture device and method of manufacturing same
US11398512B2 (en) * 2019-12-19 2022-07-26 Taiwan Semiconductor Manufacturing Company, Ltd. Photo-sensing device and manufacturing method thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6021439B2 (en) 2012-05-25 2016-11-09 キヤノン株式会社 Solid-state imaging device
CN111989783B (en) 2018-11-19 2024-02-13 松下知识产权经营株式会社 Image pickup apparatus and image pickup system
WO2022024718A1 (en) 2020-07-30 2022-02-03 パナソニックＩｐマネジメント株式会社 Photodetector, solid-state imaging device, and method for manufacturing photodetector

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006049825A (en) * 2004-07-08 2006-02-16 Matsushita Electric Ind Co Ltd Solid state imaging device and its manufacturing method
JP2007305683A (en) * 2006-05-09 2007-11-22 Fujifilm Corp Solid state image sensing element and method for manufacturing the same
JP2008016559A (en) * 2006-07-04 2008-01-24 Fujifilm Corp Solid-state imaging apparatus
JP2008091771A (en) * 2006-10-04 2008-04-17 Matsushita Electric Ind Co Ltd Solid-state image pickup device and its manufacturing method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006049825A (en) * 2004-07-08 2006-02-16 Matsushita Electric Ind Co Ltd Solid state imaging device and its manufacturing method
JP2007305683A (en) * 2006-05-09 2007-11-22 Fujifilm Corp Solid state image sensing element and method for manufacturing the same
JP2008016559A (en) * 2006-07-04 2008-01-24 Fujifilm Corp Solid-state imaging apparatus
JP2008091771A (en) * 2006-10-04 2008-04-17 Matsushita Electric Ind Co Ltd Solid-state image pickup device and its manufacturing method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013035258A1 (en) * 2011-09-06 2013-03-14 パナソニック株式会社 Solid-state image capture device and method of manufacturing same
US11398512B2 (en) * 2019-12-19 2022-07-26 Taiwan Semiconductor Manufacturing Company, Ltd. Photo-sensing device and manufacturing method thereof
US20220320169A1 (en) * 2019-12-19 2022-10-06 Taiwan Semiconductor Manufacturing Company, Ltd. Photo-sensing device and manufacturing method thereof

Also Published As

Publication number Publication date
JP2012114155A (en) 2012-06-14

Similar Documents

Publication Publication Date Title
US8669632B2 (en) Solid-state imaging device and method for manufacturing the same
JP5639748B2 (en) Solid-state imaging device and manufacturing method thereof
US8003929B2 (en) Solid-state image pickup device with an optical waveguide, method for manufacturing solid-state image pickup device, and camera
US8711258B2 (en) Solid-state imaging device and method for manufacturing the same
JP6325620B2 (en) Semiconductor device and manufacturing method thereof
US20100203665A1 (en) Methods of manufacturing an image sensor having an air gap
US8823123B2 (en) Solid-state image sensor
TWI699007B (en) Solid-state imaging devices
JP2008192951A (en) Solid state imaging apparatus and manufacturing method thereof
WO2012070165A1 (en) Solid-state imaging device and method for fabricating same
KR20080030950A (en) Solid-state imaging apparatus
US20120199928A1 (en) Semiconductor device and method for manufacturing the same
JP2012182427A (en) Method of manufacturing semiconductor device
WO2013054535A1 (en) Solid-state imaging device and manufacturing method therefor
JP2013207053A (en) Solid state imaging device and electronic apparatus
US9391227B2 (en) Manufacturing method of semiconductor device
JP2011243885A (en) Solid-state imaging device and method of manufacturing the same
JP4846878B1 (en) Solid-state imaging device
JP7194918B2 (en) Solid-state image sensor
WO2013035258A1 (en) Solid-state image capture device and method of manufacturing same
JP7457989B2 (en) Photodetector, solid-state imaging device, and method for manufacturing photodetector
US20150187831A1 (en) Solid state imaging device
CN117460358A (en) Display panel and display device
JP2013141019A (en) Semiconductor device manufacturing method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11843670

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 11843670

Country of ref document: EP

Kind code of ref document: A1