JP2006351775A - Method of manufacturing color filter, method of manufacturing solid-state imaging device and the solid-state imaging device employing the filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a color filter which can form a high-accuracy pattern, prevent color mixture and realize reduction in thickness. <P>SOLUTION: A filter separation layer 50F is formed, in advance, and the color filter material of a corresponding color is formed, while forming an opening on each color forming region and flattening is executed, and thus, a color filter in which color sections are defined with high accuracy can be formed. Furthermore, since color filters of adjacent colors are separated by the color separating layer, highly accurate pattern can be formed without the risk of color mixture reduction in thickness. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a color filter, a method for manufacturing a solid-state imaging device, and a solid-state imaging device using the same, and more particularly to a method for forming a thin and flat color filter.

  In general, color filters used in MOS-type and CCD-type solid-state imaging devices, etc., use colored resists of three or four colors, and are patterned on a flat surface by a resist coating process and a development process. (For example, refer to Patent Document 1 below).

  The color filter is manufactured as follows. First, a color resist, for example, a B (blue) color filter material is applied on a flat surface, patterned by exposure and development, and then fixed by heat treatment or ultraviolet irradiation, so that the B color filter Form. Next, a colored resist, for example, a G (green) color filter material is applied onto the B color filter and the flat surface, exposed and developed for patterning, and then fixed by heat treatment or ultraviolet irradiation. Thus, a G color filter is formed. Finally, on the B and G color filters and the flat surface, for example, a colored resist, which is an R (red) color filter material, is applied, patterned by exposure and development, and then subjected to heat treatment or ultraviolet irradiation. By fixing, an R color filter is formed. For example, in an example of a conventional color filter, since the photosensitive group P is contained, the density of the coloring group is low, and since the patterning is performed by wet processing by development, a residue containing the coloring group is attached. is there.

  In addition, in order to form a color filter flat, a method of forming a color filter pattern by a dry process by forming a positive resist and forming an organic pigment thereon (Patent Document 2) has also been proposed. However, there are problems such as difficulty in stripping the resist.

JP-A-6-273611 JP 2002-314058 A

  In recent years, demands for higher resolution and higher sensitivity have been increasing in solid-state imaging devices, and the number of imaging pixels has been increasing to more than gigapixels. Under such circumstances, in order to obtain high resolution without increasing the chip size, it is necessary to reduce the area per unit pixel and achieve high integration. Furthermore, the substrate (silicon substrate) on which the solid-state imaging device is built is mounted by further stacking lenses on the filter. For this reason, the positional accuracy between the lens and the photoelectric conversion unit is important, and the distance, that is, the distance in the height direction, is not only for the purpose of ensuring the positional accuracy in the manufacturing process, but also the sensitivity during use (photoelectric conversion efficiency). It is also an important factor in terms.

  By the way, in such a solid-state imaging device, when patterning a color filter material due to miniaturization, it has become impossible to obtain sufficient patterning accuracy by the above-described method.

In addition, since the development process of the colored resist for forming the filter layer of each color is a wet process, it is difficult to form a sharp pattern edge, and it is easy to form a tapered cross section, which is also a cause of color mixing due to light wraparound It is easy to become. In addition, after development, the surface is washed with pure water, and a filter layer pattern for each color is formed through a rinsing process. At this time, there is also a problem that the colored resist in the liquid removed in the developing process tends to adhere again. It was.
Even if high-accuracy pattern formation can be realized, the problem of color mixing due to the incidence of light from an oblique direction increases as the thickness is reduced, and a thin color filter without color mixing has been demanded.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a color filter that enables high-precision pattern formation, prevents color mixing, and realizes thinning.
Another object of the present invention is to provide a solid-state imaging device that is highly sensitive and highly reliable even when it is thinned and is highly miniaturized.

  The color filter manufacturing method of the present invention includes a first color filter constituting the first color filter and a second color filter different from the first color on the substrate surface. A method of manufacturing a color filter in which two color filters are arranged, the step of forming a filter separation layer for separating the color filters of each color on the surface of the substrate, and a first step in the filter separation layer A step of forming a first opening for forming a color filter; a step of applying a color filter material of a first color to the surface of the substrate on which the first opening is formed; planarization by CMP; Forming a first color filter in which one opening is filled with a color filter material of a first color; and forming a second color in the filter separation layer in which the first color filter is formed. A step of forming a second opening for forming a filter; a step of applying a color filter material of a second color to the surface of the substrate on which the second opening is formed; Removing the second color filter material above to form a second color filter filled with the second color filter material in the second opening, the first color The filter and the second color filter are arranged on the substrate.

  By this method, the filter separation layer is formed, and the color filter material of the corresponding color is formed and flattened while forming the opening in the formation region of each color. A defined color filter can be formed. In addition, since the adjacent color filters are separated by the filter separation layer, a highly accurate pattern can be formed without the risk of color mixing even when the thickness is reduced. Furthermore, since the color filter material of the first color is patterned by dry etching, there is no residue formed on the surface of the substrate, and no residue adheres, and a high-precision with a sharp pattern edge. A pattern can be formed. Further, the flattening step can surely remove the color filter material of the first color on the upper layer and prevent the residue from remaining. The step between adjacent color filters can be further reduced, and further color mixing can be prevented and the thickness can be reduced. Further, since adjacent color filters are separated, color mixture can be prevented even if a dye-based color filter is used. Furthermore, since it is not necessary to have a photosensitive group in the color filter material itself during patterning, the content of unnecessary photosensitive groups can be reduced when used as a filter, the translucency is improved, and the colored group is improved. Therefore, the film thickness as a whole can be reduced, the loss of light amount can be reduced even when miniaturization is performed, and a highly sensitive element can be formed.

  In the color filter manufacturing method of the present invention, the step of forming the second opening is different from the step of forming a photosensitive resist pattern by photolithography on the surface of the filter separation layer, and using the photosensitive resist pattern as a mask. Forming a second opening in the filter separation layer by isotropic etching, and forming a color filter material of the second color while leaving the photosensitive resist pattern.

  By this method, the contact between the colors can be reliably eliminated, so that color mixing due to the residue of the coloring group can be prevented.

  In the color filter manufacturing method of the present invention, the filter separation layer has a thickness of 0.5 μm or less.

  By this method, a color filter layer having the same thickness is formed, and the thickness can be further reduced. The width of the filter separation layer is desirably 0.2 μm or less.

  In the color filter manufacturing method of the present invention, the step of forming the filter separation layer includes a step of forming a silicon oxide film by a plasma CVD method.

  By this method, this filter separation layer is formed of a silicon oxide film formed by a plasma CVD method, so that a dense and highly separable region can be formed.

  The color filter manufacturing method of the present invention includes a step of forming a silicon nitride film prior to the step of forming the filter isolation layer, and the first and second openings are formed using the silicon nitride film as a stopper. I did it.

  This method makes it possible to form a filter separation layer having a defined section with high accuracy, and since this stopper layer is made of silicon nitride, it is also effective as a passivation film, increasing the film thickness and consequently the height of the element. A highly reliable solid-state imaging device can be formed without causing an increase.

  In addition, the color filter manufacturing method of the present invention includes a step of forming an organic film prior to the step of forming the filter separation layer, and the first and second openings are formed using the organic film as a stopper. It is characterized by that.

  By this method, it is easy to form and can be formed without going through a high temperature process.

  In the color filter manufacturing method of the present invention, the step of forming the second filter layer by the planarization is a CMP step.

  By this method, it is possible to reliably pattern the filter layer without an overlapping portion.

  In the color filter manufacturing method of the present invention, the step of forming the second filter layer by the planarization is an etch back step.

  By this method, it is possible to reliably pattern the filter layer without an overlapping portion.

  According to another aspect of the present invention, there is provided a method for manufacturing a solid-state image pickup device comprising: a step of forming a solid-state image pickup element portion having solid-state image pickup elements arranged on a substrate surface; and a step of forming a color filter on the solid-state image pickup element. In the manufacturing method, the color filter forming step includes a step of forming a planarizing film on the solid-state imaging element formed on the substrate surface, and then forming a silicon nitride film on the planarizing film. Forming a filter separation layer for separating the color filters of each color on the upper layer, and forming a first opening for forming a first color filter in the filter separation layer using the silicon nitride film as an etching stopper; A step of applying a color filter material of a first color to the surface of the substrate on which the first opening is formed, planarizing by CMP, and applying a first color to the first opening. Forming a first color filter filled with a color filter material of color, and using the silicon nitride film as an etching stopper, a second color filter is formed on the filter separation layer on which the first color filter is formed A step of forming a second opening for forming a color filter material; a step of applying a color filter material of a second color to the surface of the substrate on which the second opening is formed; Removing the second color filter material, and forming a second color filter filled with the second color filter material in the second opening, and the first color filter. And a second color filter are arranged on the substrate.

  By this method, it is possible to form a solid-state imaging device having no color mixing and having a thin color filter layer.

  Further, in the method for manufacturing a solid-state imaging device according to the present invention, after the step of forming the second color filter, the step of forming a third opening in the filter separation layer, A step of applying a color filter material of the third color to the formed substrate surface and planarization remove the color filter material of the third color on the filter separation layer, and a third color is formed in the third opening. Forming a third color filter filled with a color filter material of a predetermined color, and arranging the first color filter, the second color filter, and the third color filter on the substrate.

  In the method for manufacturing a solid-state imaging device of the present invention, the first color is blue, the second color is red, and the third color is green.

  By this method, a full-color solid-state imaging device can be efficiently formed.

  Moreover, the manufacturing method of the solid-state image sensor of this invention includes the process of forming a micro lens after the formation process of the said color filter.

  By this method, a thinner solid-state image sensor can be formed.

  Moreover, the manufacturing method of the solid-state image sensor of this invention includes the process of removing the said filter separation layer and forming the filter separation area | region which consists of an air gap layer after formation of the said micro lens.

  By this method, the air gap layer can be easily formed, and incident light can be more efficiently guided to the color filters of the respective colors.

  Moreover, the manufacturing method of the solid-state imaging device of the present invention includes a step of performing surface treatment with oxygen radicals after the step of removing the filter separation layer.

  By this method, etching damage in the process of removing the filter separation layer can be removed, and incident light can be more efficiently guided to the color filters of the respective colors.

  The solid-state imaging device of the present invention includes a photoelectric conversion unit, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, and a wiring layer connected to the charge transfer unit. A solid-state imaging device comprising a peripheral circuit section and having a color filter formed at least on the upper layer of the photoelectric conversion section; and a first color filter of a first color so as to face the photoelectric conversion section; A second color filter of a second color different from the first color is arranged in parallel, and ends of the first and second color filters are separated from each other.

  With this configuration, color mixing can be prevented and the thickness can be reduced. Further, since adjacent color filters are separated, color mixture can be prevented even if a dye-based color filter is used.

  The solid-state imaging device of the present invention is characterized in that the end portions of the first and second color filters are separated via an air gap.

  With this configuration, incident light can be more efficiently guided to the color filters of the respective colors.

  In the solid-state imaging device of the present invention, the end portions of the first and second color filters are disposed via a filter separation layer made of a highly refractive material.

  With this configuration, incident light can be efficiently guided to the color filters of each color.

  In the solid-state imaging device of the present invention, the high refractive material has a refractive index of 1.9 or more.

  With this configuration, incident light can be more efficiently guided to the color filters of the respective colors.

  The solid-state imaging device of the present invention includes a solid-state imaging device in which a microlens is disposed on the color filter.

  With this configuration, a thinner solid-state imaging device can be provided.

According to the present invention, a color filter that is easy to manufacture, thin, and has little transmission loss can be obtained, and a color filter having no color mixture can be formed because the filter separation layer is provided.
In addition, since the color filter area of each color is defined by the pattern of openings formed in the filter separation layer, the pattern edge can be made vertical (steep), the pattern accuracy can be improved, and color mixing can be suppressed. Can measure.
In addition, it is possible to improve stains and unevenness due to adhesion of pigments and dyeing groups of the color filter.
According to the solid-state imaging device manufacturing method using this color filter manufacturing method, the sensitivity can be improved by reducing the thickness of the color filter layer.
Further, color mixing of the color filter can be prevented and the thickness can be reduced, and a thin and fine high-sensitivity solid-state imaging device can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The color filter described in the present embodiment is used for a solid-state image sensor, for example.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a solid-state imaging device for explaining Embodiment 1 of the present invention, and FIG. 2 is a schematic plan view. 1 is a schematic cross-sectional view taken along the line AA of FIG. 2, FIGS. 3A and 3B are diagrams showing this color filter, and FIGS. 4 to 8 show a manufacturing process of the color filter in this solid-state imaging device. It is process sectional drawing.
As shown in FIG. 1, in this solid-state imaging device, the color filter 50 is separated and formed above the photodiode 30 by separating the color filters 50R, 50G, and 50B of each color through a frame-like filter separation layer 50F. It is characterized by that. The color filter material of each color is composed of a resin material having a photosensitive group content of 0, and first to third layers formed on the silicon oxide layer constituting the filter separation layer 50F so as to face each photodiode 30. A color filter material of each color is filled in each opening to constitute a red color filter 50R (not shown) as a first to third color filter, a green color filter 50G, and a blue color filter 50B. ing. Here, high-precision first to third opening patterns patterned by dry etching through photolithography are arranged on the silicon oxide layer constituting the filter separation layer 50F. In this color filter, a red color filter 50R (not shown), a green color filter 50G, and a blue color filter 50B are arranged on the lower flattening film 74 so as to correspond to each photodiode 30. Each pattern edge is formed to be vertical, and the surface is a flat surface. In FIG. 2, reference numerals (R, G, B) indicating the color filters formed above the photodiodes 30 are attached to the photodiodes 30.

  3A and 3B schematically show the color filter. Fig.3 (a) is AA sectional drawing of FIG.3 (b). The filter separation layer 50F is patterned with high accuracy by dry etching, and the color filter material formed in the opening does not contain a photosensitive group, so that the coloring is formed at a high density, and the pattern edge is also vertical. Yes.

  Others have a usual structure, but photodiodes 30 as photoelectric conversion parts are arranged on the surface of the n-type silicon substrate 1 and signal charges generated by the photodiodes 30 are arranged in the column direction (in FIG. 2). The charge transfer section 40 for transferring in the Y direction) meanders between a plurality of photodiode columns composed of a plurality of photodiodes 30 arranged in the column direction. Then, the odd-numbered photodiode rows are formed so as to be shifted in the direction of approximately half the array pitch of the photodiodes 30 arranged in the column direction with respect to the even-numbered photodiode rows.

  The charge transfer unit 40 includes a plurality of charge transfer channels 33 formed in the column direction of the surface portion of the silicon substrate 1 corresponding to each of the plurality of photodiode columns, and a charge transfer formed in the upper layer of the charge transfer channel 33. It includes an electrode 3 (first layer electrode 3a, second layer electrode 3b) and a charge readout region 34 for reading out charges generated in the photodiode 30 to the charge transfer channel 33. The charge transfer electrode 3 has a meandering shape extending in the row direction (X direction in FIG. 2) as a whole between a plurality of photodiode rows composed of a plurality of photodiodes 30 arranged in the row direction. . Here, the charge transfer electrode 3 has a single layer electrode structure in which a second layer electrode is formed on the first layer electrode via an interelectrode insulating film and is flattened by CMP, but is not limited to a single layer electrode structure. A two-layer electrode structure in which a part of the first layer electrode is covered with the second layer electrode may be used.

  As shown in FIG. 1, a p well layer 1P is formed on the surface of the silicon substrate 1, an n region 30b for forming a pn junction is formed in the p well layer 1P, and a p region 30a is formed on the surface. The photodiode 30 is configured, and the signal charge generated in the photodiode 30 is accumulated in the n region 30b.

  On the right side of the photodiode 30, a charge transfer channel 33 composed of an n region is formed with a slight distance. A charge readout region 34 is formed in the p-well layer 1P between the n region 30b and the charge transfer channel 33.

A gate oxide film 2 is formed on the surface of the silicon substrate 1, and a first electrode 3 a and a second electrode 3 b are formed on the charge readout region 34 and the charge transfer channel 33 via the gate oxide film 2. The An interelectrode insulating film 5 is formed between the first electrode 3a and the second electrode 3b. A channel stop 32 made of a p ⁺ region is provided on the right side of the vertical transfer channel 33, and is separated from the adjacent photodiode 30.

  An insulating film 6 such as a silicon oxide film and an antireflection layer 7 are formed on the charge transfer electrode 3, and an intermediate layer 70 is further formed thereon. Of the intermediate layer 70, 71 is a light shielding film, 72 is an insulating film made of BPSG (borophosphosilicate glass), 73 is an insulating film (passivation film) made of P-SiN, and 74 is a flattening film under a filter made of transparent resin or the like. However, in this embodiment, the under-filter planarizing film 74 serves as a stopper for forming an opening for patterning the filter separation layer 50F. The light shielding film 71 is provided except for the opening of the photodiode 30. A color filter and a microlens 60 are provided above the intermediate layer 70. Between the color filter and the micro lens 60, an on-filter planarizing film 61 made of an insulating transparent resin or the like is formed.

  In the solid-state imaging device according to the present embodiment, signal charges generated in the photodiode 30 are accumulated in the n region 30b, and the accumulated signal charges are transferred in the column direction by the charge transfer channel 33, and the transferred signals are transferred. The charge is transferred in the row direction by a horizontal charge transfer path (HCCD) (not shown), and a color signal corresponding to the transferred signal charge is output from an amplifier (not shown). In other words, on the silicon substrate 1, a solid-state imaging device unit that is a region including a photoelectric conversion unit, a charge transfer unit, an HCCD, and an amplifier, and a peripheral circuit that is a region where peripheral circuits (PAD unit and the like) of the solid-state imaging device are formed. Are formed to constitute a solid-state imaging device.

Next, the manufacturing process of the above-described solid-state imaging device will be described.
First, the manufacturing process before forming the color filter will be described.
Impurities are introduced into the surface of the n-type silicon substrate 1 to form a p-well layer 1P, a charge transfer channel 33, a charge readout region 34, a channel stop layer 32, and the like, and then a gate oxide film 2 is formed. Subsequently, a first conductive film constituting the first layer electrode 3a is formed on the gate oxide film 2, and patterning is performed to form the first layer electrode 3a and peripheral circuit wiring. Next, an insulating film 5 made of a silicon oxide film is formed around the first layer electrode 3a, and a second conductive film constituting the second layer electrode 3b is formed thereon. Next, the second conductive film 3b is planarized by CMP and patterned to form the second layer electrode 3b. Next, after forming the insulating film 6 so as to cover the charge transfer electrodes 3, the n region 30b and the p region 30a in the photodiode region are formed, and then the light shielding film is opened to the light receiving region in the photodiode region. 71 is formed. Next, an insulating film 72 is formed and planarized by high temperature reflow.

Next, after forming a contact hole in the upper part of the peripheral circuit of the insulating film 72, a metal material is formed and patterned to form a bonding pad (not shown). Then, a passivation film 73 made of a silicon nitride film is formed by a CVD method, and the passivation film on the bonding pad is selectively etched away to form an opening to expose the bonding pad. Thereafter, sintering is performed in an inert gas atmosphere containing H _2, and then a planarizing film having a thickness of 0.5 to 2.0 μm is formed by spin coating or scan coating. Here, in order to avoid confusion with other planarization films, this planarization film is referred to as an under-filter planarization film 74. The manufacturing process so far is a usual method. As the planarizing film 74 under the filter, a resist material transparent to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.) is used.

  The under-filter flattening film 74 is not essential when the lower layer is flat, and an example in which the under-filter flattening film 74 is not used in the following steps will be described. When the under-filter planarizing film 74 made of an organic film is used, it may be used as an etching stopper for forming an opening in the filter separation layer 50F.

  Next, the manufacturing process of the color filter will be described in detail with reference to FIGS.

Next, the manufacturing process of the color filter will be described in detail with reference to FIGS.
These are diagrams showing each manufacturing process of the color filter of the present embodiment. In each figure, the red color filter 50R is "R", the green color filter 50G is "G", and the blue color filter 50B. The letter “B” is added to the symbol. In this embodiment, a CMP process for planarization is performed. As each RGB color filter material, a material whose polishing rate is about 1: 1 with the resist in the CMP process is used. In the present embodiment, “B” corresponds to the first color, and “R” and “G” correspond to the second color and the third color. In each plan view, a lower layer than the insulating film 72 as a planarizing film is omitted.

  First, as shown in FIG. 4A, after a wiring layer (not shown) is formed on the planarizing film 72, a passivation film 73 made of a silicon nitride film is formed by plasma CVD, and this passivation film 73 is formed. As shown in FIG. 4B, a silicon oxide film having a thickness of 0.5 μm is formed by plasma CVD. Here, the passivation film 73 is formed to have a high refractive index of 1.9 or higher.

Then, as shown in FIG. 5A, a resist pattern R1 is formed by photolithography. Thereafter, as shown in FIG. 5B, a first opening O1 is formed by reactive ion etching (RIE) using the resist pattern R1 as a mask.
Then, the resist pattern R1 is removed by ashing to form a filter separation layer 50F in which the first opening O1 is formed (FIG. 5C).
Then, a blue color filter material is applied as a color filter material of the first color so as to be 0.5 to 2.0 μm. This color filter material does not contain a photosensitive group. By this step, the blue color filter material is filled in the first opening O1. In this state, the blue color filter material pattern is cured by heat treatment and ultraviolet irradiation (FIG. 5D) and planarized by CMP to form a blue color filter 50B (FIG. 5D). e)).

  Thereafter, as shown in FIG. 6A, a resist pattern R2 for forming a red color filter pattern is formed by photolithography. Here, it has a shape having an opening in a region to be a red color filter.

  Thereafter, as shown in FIG. 6B, reactive ion etching (RIE), which is anisotropic dry etching, is performed using the resist pattern R2 as a mask to form a red color filter material pattern. Two openings O2 are formed. Again, the underlying silicon nitride film 73 acts as an etching stopper.

Then, while leaving the resist pattern R2, the red color filter material R is applied to a film thickness of 0.5 to 2.0 μm, and the pattern of the red color filter material is cured by heat treatment and ultraviolet irradiation. (FIG. 6C).
Thereafter, CMP is performed to flatten the surface, and a red color filter 50R is formed (FIG. 7A).

  Thereafter, as shown in FIG. 7B, a resist pattern R3 for forming a green color filter pattern is formed by photolithography. Here, it has a shape having an opening in a region to be a green color filter.

  Thereafter, as shown in FIG. 7C, reactive ion etching (RIE), which is anisotropic dry etching, is performed using the resist pattern R3 as a mask to form a green color filter material pattern. 3 openings O3 are formed. Again, the underlying silicon nitride film 73 acts as an etching stopper.

Then, while leaving the resist pattern R3, the green color filter material 50G (G) is applied to a film thickness of 0.5 to 2.0 μm, and the green color filter material pattern is subjected to heat treatment and ultraviolet irradiation. It hardens | cures by (FIG. 8 (a)).
Thereafter, CMP is performed to flatten the surface to form a green color filter 50G (FIG. 8B).

  By this CMP process, the color filter surface of each color is flat, and a highly accurate color filter pattern can be formed without residue.

  Then, on this color filter, a resist material transparent to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.) is applied so as to have a film thickness of 0.5 to 2.0 μm. A chemical film 61 is formed. Thereafter, a microlens 60 is formed on the planarizing film 61 by an etching method, a melt method, or the like (FIG. 8C), thereby forming a solid-state imaging device as shown in FIG.

  As described above, according to the manufacturing method of the present embodiment, the silicon oxide film to be the filter separation layer 50F is sequentially dry-etched by RIE using the resist pattern formed by photolithography as a mask to form an opening. In addition, since the color filter material is sequentially filled, it is possible to form only a material necessary as a filter component such as a coloring group without using a photosensitive group, and a thinner and highly accurate pattern can be formed. In addition, since the height of the color filter from the surface of the passivation film 73 (flattening film 74) can be made lower than before, the solid-state imaging device can be made thinner. As a result, a margin for obliquely incident light is widened, and a highly sensitive solid-state imaging device can be manufactured. In addition, since the filter separation layer 50F exists between adjacent color filters, it is possible to reliably prevent color mixing.

  In addition, when a dye-based or pigment-dispersed color filter material is used as the color filter material, a residue is generated during washing with water after forming the pattern of the color filter material, which adheres to the color filters of other colors. Then, although it becomes a factor that degrades the optical characteristics, particularly the image quality, according to the present embodiment, the residue can also be removed by the CMP process, so that the image quality degradation can be prevented. In particular, in the case of dye-based color filter materials, there is a problem of dye bleeding, but according to the present invention, since the color filters of each color are separated by the filter separation layer, bleeding can be reliably prevented. .

  In addition, the color filter obtained by the method of the present embodiment has a vertical section with a steep boundary between adjacent color filters, and the surface thereof is substantially flattened. It is also possible to form the microlens 60 directly on the color filter surface without forming it. According to this configuration, the solid-state imaging device can be further thinned, the manufacturing process can be reduced by one step, and a high-sensitivity solid-state imaging device can be manufactured at low cost.

  In the present embodiment, the CMP process is performed using the already formed B color filter 50B or the like as a stopper, but it is also possible to perform the CMP process without using the stopper. In this case, the thickness of the R color filter 50R and the G color filter 50G at a position higher than the height from the surface of the planarizing film 74 of the B color filter 50B is utilized by using a known end point detection function or time polishing. The CMP process may be performed so that the thickness is 50 nm or less. This 50 nm is a value in a range that is acceptable as a step. In this case, the order of forming the color filters is not limited to that described above, and can be changed as appropriate.

  In this embodiment, the solid-state imaging device having a configuration in which photodiodes are arranged in a honeycomb shape has been described. However, the present invention is not limited thereto, and a configuration in which a plurality of photodiodes are arranged in a square lattice shape is described. The present invention can also be applied to other solid-state imaging devices.

  In this embodiment, an RGB primary color filter is used as an example, but the present invention can also be applied to cyan, magenta, and yellow complementary color filters.

(Embodiment 2)
Next, a solid-state image sensor according to Embodiment 2 of the present invention will be described.
In the first embodiment, the color filters are separated by the filter separation layer 50F. However, in this embodiment, as shown in FIG. 9, there is no filter separation layer 50F and the color filters of the respective colors are separated by the air gap layer. It is characterized by being G. In the present embodiment, the under-filter planarizing layer 74 is not formed. Since it is the same as that of the first embodiment, description thereof is omitted.

  In manufacturing, after forming the microlens 60 in the first embodiment (FIG. 8C), the filter separation layer 50F made of a silicon oxide film is etched to form the air gap G. The lower layer of the air gap is a passivation film 73 made of a silicon nitride film, and the upper layer is formed with the microlens 60 via the filter upper planarizing film 61, so that the passivation property is sufficient, and the high refractive index region Is formed, and incident light from an oblique direction can be efficiently guided to the photodiode.

  As described above, according to the present embodiment, in addition to the effect of the method of the first embodiment, the region between the filters can be made to have a high refractive index, so that the light condensing property can be further improved.

  According to this configuration, since color mixing can be prevented and a thin color filter layer can be formed, the thickness can be further reduced, and it is useful as a solid-state imaging device in an electronic device such as a portable terminal.

1 is a schematic cross-sectional view of a solid-state imaging device according to Embodiment 1 of the present invention. 1 is a schematic plan view of FIG. Schematic diagram showing the structure of the color filter of the first embodiment The figure which shows the manufacturing process of the color filter of this Embodiment 1. The figure which shows the manufacturing process of the color filter of this Embodiment 1. The figure which shows the manufacturing process of the color filter of this Embodiment 1. The figure which shows the manufacturing process of the color filter of this Embodiment 1. The figure which shows the manufacturing process of the color filter of this Embodiment 1. The figure which shows the solid-state image sensor of this Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 N type silicon substrate 2 Gate oxide film 3a 1st layer electrode 3b 2nd layer electrode 5 Interelectrode insulating film 6 Insulating film 7 Antireflection layer 60 Micro lens 61 Planarizing film 71 Light shielding film 72 Insulating (BPSG) film 73 Passivation film 74 Flattening films 50B, 50R, 50G Color filter 50F Filter separation layer G Air gap layer

Claims (19)

A first color filter constituting a first color filter and a second color filter constituting a second color filter different from the first color are arranged on the substrate surface. A color filter manufacturing method comprising:
Forming a filter separation layer for separating the color filters of each color on the surface of the substrate;
Forming a first opening for forming a first color filter in the filter separation layer;
Applying a color filter material of a first color to the surface of the substrate on which the first opening is formed;
Flattening by CMP and forming a first color filter in which the first opening is filled with a color filter material of a first color;
Forming a second opening for forming a second color filter in the filter separation layer formed with the first color filter;
Applying a second color filter material to the surface of the substrate on which the second opening is formed;
Removing the second color filter material on the filter separation layer by planarization to form a second color filter filled with the second color filter material in the second opening; Including
A method for manufacturing a color filter, wherein the first color filter and the second color filter are arranged on the substrate. It is a manufacturing method of the color filter of Claim 1, Comprising:
Forming the second opening includes forming a photosensitive resist pattern by photolithography on the surface of the filter separation layer;
Forming a second opening in the filter separation layer by anisotropic etching using the photosensitive resist pattern as a mask;
A method for producing a color filter, wherein the second color filter material is formed with the photosensitive resist pattern remaining. It is a manufacturing method of the color filter of Claim 1, Comprising:
The method for producing a color filter, wherein the filter separation layer has a thickness of 0.5 μm or less. It is a manufacturing method of the color filter of Claim 2, Comprising:
The step of forming the filter separation layer is a method for manufacturing a color filter, including a step of forming a silicon oxide film by a plasma CVD method. A method for producing a color filter according to claim 4,
Prior to the step of forming the filter separation layer,
Including a step of forming a silicon nitride film,
A method of manufacturing a color filter, wherein the first and second openings are formed using the silicon nitride film as a stopper. A method for producing a color filter according to claim 4,
Prior to the step of forming the filter separation layer,
Including a step of forming an organic film,
A method of manufacturing a color filter, wherein the first and second openings are formed using the organic film as a stopper. A method for producing a color filter according to any one of claims 1 to 6,
The step of forming the second filter layer by the planarization includes:
A method for producing a color filter, which is a CMP process. It is a manufacturing method of the color filter in any one of Claims 1 thru | or 6, Comprising:
The step of forming the second filter layer by the planarization includes:
A method for producing a color filter, which is an etch-back process. A method for manufacturing a solid-state imaging device, comprising: a step of forming a solid-state imaging device section in which solid-state imaging devices are arranged on a substrate surface; and a step of forming a color filter on the solid-state imaging device,
The step of forming the color filter includes
After forming a planarization film on the solid-state image sensor formed on the substrate surface,
Forming a silicon nitride film on the planarizing film;
Furthermore, a process of forming a filter separation layer for separating the color filters of each color on this upper layer,
Forming a first opening for forming a first color filter in the filter separation layer using the silicon nitride film as an etching stopper;
Applying a color filter material of a first color to the substrate surface on which the first opening is formed;
Flattening by CMP and forming a first color filter in which the first opening is filled with a color filter material of a first color;
Forming a second opening for forming a second color filter in the filter separation layer, in which the first color filter is formed, using the silicon nitride film as an etching stopper;
Applying a color filter material of a second color to the substrate surface on which the second opening is formed;
Removing the second color filter material on the filter separation layer by planarization to form a second color filter filled with the second color filter material in the second opening; Including
A method for manufacturing a solid-state imaging device, wherein the first color filter and the second color filter are arranged on the substrate. It is a manufacturing method of the solid-state image sensing device according to claim 9,
After the step of forming the second color filter, further forming a third opening in the filter separation layer;
Applying a color filter material of a third color to the substrate surface on which the third opening is formed;
Removing a third color filter material on the filter separation layer by planarization to form a third color filter filled with the third color filter material in the third opening; Including
A method for manufacturing a solid-state imaging device, wherein the first color filter, the second color filter, and a third color filter are arranged on the substrate. It is a manufacturing method of the solid-state image sensing device according to claim 9,
The first color is blue;
The second color is red;
A method for manufacturing a solid-state imaging device, wherein the third color is green. It is a manufacturing method of the solid-state image sensing device according to claim 9,
After the color filter forming step,
A method for manufacturing a solid-state imaging device, including a step of forming a microlens. It is a manufacturing method of the solid-state image sensing device according to claim 12,
A method of manufacturing a solid-state imaging device, including a step of removing the filter separation layer and forming a filter separation region including an air gap layer after forming the microlens. It is a manufacturing method of the solid-state image sensing device according to claim 13,
A method for manufacturing a solid-state imaging device, including a step of performing a surface treatment with oxygen radicals after the step of removing the filter separation layer. A photoelectric conversion unit, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, and a peripheral circuit unit including a wiring layer connected to the charge transfer unit, A solid-state imaging device formed by forming a color filter on the upper layer of the photoelectric conversion unit,
A first color filter of a first color and a second color filter of a second color different from the first color are arranged in parallel so as to face the photoelectric conversion unit,
The solid-state imaging device, wherein ends of the first and second color filters are separated from each other. The solid-state imaging device according to claim 15,
A solid-state imaging device, wherein end portions of the first and second color filters are separated from each other through an air gap. The solid-state imaging device according to claim 15,
A solid-state imaging device, wherein ends of the first and second color filters are arranged via a filter separation layer made of a highly refractive material. The solid-state imaging device according to claim 17,
The high refractive material is a solid-state imaging device having a refractive index of 1.9 or more. The solid-state imaging device according to claim 13,
A solid-state imaging device comprising a microlens disposed on the color filter.

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