JP2009080313A - Color filter and its manufacturing method, solid-state imaging element using this filter and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high sensitive solid-state imaging element which can increase the light amount to the photoelectric converter such as a photo diode and prevent color mixing and color shading. <P>SOLUTION: The color filter is disposed facing respective photoelectric conversion areas constituting pixels to separate the lights entering the photoelectric conversion areas into colors for the respective pixels. The color filters have first color filters selectively passing a first color and second color filters selectively passing a second color different from the first color, both arranged in parallel. The first and second color filters are adjoining each other through light transmissive areas which are working as white pixels and surrounded by the side walls covered with reflective films. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color filter, a manufacturing method thereof, a solid-state imaging device using the same, and a manufacturing method thereof, and particularly relates to a color filter for forming a highly sensitive color sensor.

  In recent years, the resolution of solid-state image sensors has been increasing, and in order to prevent a decrease in sensitivity due to the increase in resolution, microlenses and color filters provided corresponding to a plurality of photoelectric conversion regions on a semiconductor substrate are arranged. It is demanded to reduce the arrangement interval of the as much as possible. In such a solid-state imaging device, it is intended to effectively use even light incident on the boundary portion of the microlens and the color filter. However, because the arrangement interval between the microlens and the color filter is narrow, the boundary of the microlens A slight misalignment between the color filter and the boundary of the color filter may cause color mixing or cause color shading (color unevenness).

Therefore, in order to solve such a problem, a method has been proposed in which the color filter is patterned using dry etching to achieve high accuracy.
For example, as one of the methods, there is a method of patterning an unnecessary portion of a color filter formed first and a flattening layer thereunder by dry etching (Patent Document 1).
A method of patterning a color filter formed first by dry etching has also been proposed (Patent Document 2).

  Although these methods can improve the accuracy of the color filter, the demand for higher sensitivity of the solid-state imaging device has been increasing as the demand for higher resolution has increased.

JP 2006-222291 A JP 2006-222290 A

  However, in the structures of Patent Documents 1 and 2, the pattern accuracy of the color filter itself is improved, but there is a limit to increasing the sensitivity.

  Under such circumstances, the demand for higher sensitivity and higher resolution is increasing in the solid-state imaging device, and the number of imaging pixels is increasing to more than gigapixels. Under these circumstances, in order to obtain high resolution without increasing the chip size, while preventing color mixing and color shading, the area per unit pixel is reduced and high integration is achieved. In order to increase sensitivity, it is an extremely important issue to improve the transmittance of the color filter and increase the amount of light guided to the photodiode.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device that has high sensitivity and can suppress color mixing and color shading.

Therefore, the color filter of the present invention is a color filter that is disposed so as to face each of a plurality of photoelectric conversion regions constituting a pixel and separates light incident on the photoelectric conversion region for each pixel, The color filter includes a light-transmitting region that constitutes a white pixel, a first color filter that is filled in a recess formed in the light-transmitting region and selectively transmits a first color, and the first color filter. And a second color filter that selectively transmits a second color different from the first color.
According to this configuration, the light-transmitting region constituting the white pixel and the first and second color filters filled in the concave portions formed in the light-transmitting region are provided, and the transmittance is high. Sensitivity can be improved by supplementing (using) information for white pixels with pixels having a color filter having lower transmittance than the surrounding white pixels.

In the solid-state imaging device according to the aspect of the invention, the first and second color filters may be disposed adjacent to each other via a light-transmitting region that forms a white pixel around the first color filter. Of the inner walls of the recess, the side walls include those coated with a reflective layer.
With this configuration, the side walls of the white pixels arranged between all the color pixels are covered with the reflective layer, so that color mixing can be prevented and the image quality can be improved.

  The present invention includes the color filter, wherein the reflective layer is a reflective metal layer.

  The present invention provides the color filter, wherein the reflective layer has a predetermined refractive index difference with respect to the translucent region, and incident light is transmitted at an interface between the reflective layer and the translucent region. Including those formed so as to reflect.

  The present invention includes the color filter, wherein the reflective layer is a multilayer film and is formed so that incident light can be reflected at an interface between the reflective layer and the translucent region.

  The present invention includes the color filter, wherein the reflective layer is formed through an adhesive film that covers the translucent region constituting the inner wall of the recess.

  The present invention includes the color filter having a protective layer integrally formed so as to cover the inner wall of the concave portion so as to cover the reflective layer.

  The present invention includes the color filter in which the translucent region is composed of a translucent resin layer formed on the photoelectric conversion region.

The present invention includes the color filter formed on the upper layer of the photoelectric conversion portion via a planarizing film.
With this configuration, a highly accurate color filter pattern can be formed.

  The present invention includes the color filter, wherein the translucent region is a planarization film formed in an upper layer of the photoelectric conversion unit, and the recess is formed in the planarization film.

  The present invention includes the color filter in which the reflective layer is formed so as to cover the entire side wall.

  The present invention includes the color filter in which the reflective layer is formed so as to cover an upper edge portion of the side wall.

The present invention includes the color filter, wherein the first and second color filters constitute a tapered surface whose width or diameter decreases as the photoelectric conversion unit is approached.
With this configuration, the tolerance for displacement of the filter is further improved.

In the present invention, the color filter further includes a third color filter that selectively transmits the third color.
With this configuration, full color can be achieved.

According to the present invention, in the color filter, the color filter is configured such that the white pixel and the first to third color filters formed of the light-transmitting region have different areas for each color. Including.
With this configuration, various corrections can be performed by changing the area ratio. Further, if the sensitivity of the photodiode is measured in advance for each color and the area ratio is adjusted so as to correct this sensitivity difference, the sensitivity difference due to the color can be corrected.

According to the present invention, in the color filter, the color filter includes a peripheral portion and a central portion having different area ratios between the translucent region and the color filter.
With this configuration, shading for each color and the difference between shading colors can be made extremely small.

The present invention includes a photoelectric conversion unit that includes the color filter and includes a plurality of photoelectric conversion regions constituting pixels, a charge transfer unit that transfers charges generated in the photoelectric conversion unit, and a charge transfer unit. And a peripheral circuit portion including a wiring layer to be connected, and the color filter is formed at least above the photoelectric conversion portion.
With this configuration, a highly sensitive solid-state imaging device can be obtained as described above.

In the solid-state imaging device, the area ratio of the first to third color filters constituting the color filter to the light-transmitting region may be adjusted according to the characteristics of each photoelectric conversion region. May be.
With this configuration, sensitivity can be adjusted for each region by changing the area ratio, and the characteristics of the solid-state imaging device can be made uniform.

Further, in the solid-state imaging device, the area of the first to third color filters constituting the color filter with the central portion and the peripheral portion of the image imaging region constituting the solid-state imaging device. You may make it adjust so that ratio may differ.
With this configuration, it is possible to make the characteristics in one solid-state imaging device uniform.

According to the present invention, a first color filter constituting a color filter of a first color and a second color filter constituting a color filter of a second color different from the first color are formed on a substrate surface. A method for producing an arrayed color filter, the method comprising: forming on the surface of the substrate a translucent film serving as a translucent region as a white pixel surrounding each color filter; and the translucent film Forming an opening for forming a color filter, and filling the substrate surface with a color filter material.
With this configuration, an opening is formed in the translucent film, a reflective film is formed on the side wall of the opening, and the color filter is filled, so that color mixing can be easily reduced and alignment is also achieved. Easy and reliable.

  Also, by this method, a light-transmitting film for forming a light-transmitting region is formed, and a color filter material of a corresponding color is formed and flattened while forming an opening in each color forming region. Therefore, it is possible to form a color filter positioned with high accuracy. In addition, since the color filters of adjacent colors are separated by the translucent region, a highly accurate pattern can be formed without fear of color mixing even when the thickness of the film is increased to reduce the dye content. Furthermore, if the color filter material of the first color is patterned by dry etching, a high-precision pattern having a steep pattern edge can be formed without forming a residual portion on the substrate surface or adhering the residue. It becomes possible to form. 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.

  According to the present invention, in the method for manufacturing a solid-state imaging device, prior to the step of filling the color filter material, a step of forming a reflective film so as to cover a side wall of the opening, and a step of forming the reflective film in the opening Filling the surface of the substrate with a color filter material.

The present invention includes the step of forming an opening so as to leave a part of the translucent film in the method for manufacturing a color filter.
According to this configuration, since the positions of all the color filters can be determined in one step, there is an effect that accuracy can be improved.

  According to the present invention, in the color filter manufacturing method, the step of forming the reflective film includes the step of forming the reflective film on the surface of the substrate on which the opening is formed, and the side wall by anisotropic etching. And leaving the reflective film only.

  The present invention includes the step of forming an adhesive film on the surface of the substrate in which the opening is formed, prior to the step of forming the reflective film, in the method for manufacturing a color filter.

According to the present invention, a first color filter constituting a color filter of a first color and a second color filter constituting a color filter of a second color different from the first color are formed on a substrate surface. A method of manufacturing an arrayed color filter, the method comprising: forming a color filter pattern in which a first color filter and a second color filter are spaced apart from each other on the surface of the substrate; Forming a translucent material for forming a translucent region constituting the white pixel so as to cover the pattern of the color filter.
According to this configuration, it is possible to easily form a color filter having a structure in which the transparent layer covers the upper layer of the color filter.

  The present invention includes the step of forming a reflective film on a side wall of the color filter in the method for manufacturing a color filter.

  The present invention includes the step of forming a reflective film on the side wall of the color filter in the method for manufacturing a solid-state imaging device.

The present invention is a method of manufacturing the solid-state imaging device, and includes a step of performing lens processing so that a part of the translucent material constitutes a lens surface. In that case, you may use the lens material which comprises a lens as a translucent material.
According to this structure, since a lens and a translucent material are integrated, thickness reduction can be achieved.

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

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

  The solid-state imaging device manufacturing method of the present invention includes a photoelectric transfer unit including a plurality of photoelectric conversion regions constituting a pixel, and a charge transfer including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit. Forming a first color filter on the surface of the base on the surface of the base on which the portion and a peripheral circuit including a wiring layer connected to the charge transfer portion are formed, and a translucent material on the upper layer Forming an opening for forming an opening for forming the second color filter in the translucent material, and forming the second color filter in the opening.

According to the color filter of the present invention, it is possible to improve the transmittance while preventing color mixing.
That is, a color filter that is easy to manufacture, can be obtained with a thin color filter with little transmission loss, and has a light-transmitting region as a white pixel covered with a reflective film. Can be formed.
The color filter area for each color is defined by the pattern of openings formed in the translucent area, so that the pattern edge can be made vertical (steep), the pattern accuracy can be improved, and color mixing can be suppressed. Can be measured.
In addition, it is possible to improve stains and unevenness due to adhesion (residue) of pigments and dyes on the color filter.
According to the solid-state imaging device manufacturing method using this color filter manufacturing method, it is possible to prevent color mixing of the color filter and to achieve a reduction in thickness, and to provide a thin and fine high-sensitivity solid-state imaging device. it can.
Furthermore, it is easy to correct color shading.
Furthermore, the tolerance for the positional deviation of the color filter is large.

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)
1 to 4 are schematic explanatory views for explaining a method of manufacturing a color filter according to the first embodiment of the present invention. In each drawing, (a) is a cross-sectional view and (b) is a schematic plan view. .
This color filter manufacturing method includes a step of forming a translucent film serving as a translucent region as a white pixel on a substrate surface, and an opening for forming a color filter by dry etching on the translucent film. And a step of filling the opening with a color filter material.

  First, as shown in FIG. 1, a photoelectric conversion part (not shown) and a charge transfer part (not shown) are formed on a silicon substrate 1, and the surface is made of a translucent material made of acrylic resin or the like. A flattening film (translucent region) 70 is formed.

Next, as shown in FIGS. 2A and 2B, an opening T is formed by reactive ion etching (anisotropic etching) using a resist pattern (not shown) formed by photolithography as a mask.
Thereafter, as shown in FIGS. 3A and 3B, a resist mask (not shown) is formed in the opening T in a region other than the region where the green color filter 50G is to be formed, and the green color filter is filled. .
Further, as shown in FIGS. 4A and 4B, a resist mask (not shown) is formed in the opening T other than the region where the red color filter 50R is formed, and the red color filter is filled. Next, a resist mask (not shown) is formed in the opening T other than the region where the blue color filter 50B is to be formed, and the blue color filter is filled.

  In this way, a color filter in which the translucent region is the white pixel 50W and the color filter of each color is surrounded by the white pixel is easily formed with high accuracy.

(Embodiment 2)
5 to 8 are schematic explanatory views for explaining a method of manufacturing a color filter according to the second embodiment of the present invention. In each drawing, (a) is a sectional view and (b) is a schematic plan view. .
In this color filter manufacturing method, in addition to the first embodiment, a reflective film 50S is formed between a white pixel and a color filter material, and other configurations are the same as those of the first embodiment.
The process up to the formation of the opening T is the same as the process of FIGS. 1 and 2 shown in the first embodiment, and is formed of the planarizing film 70 as shown in FIG. A silicon nitride film as the reflective film 50S is formed in the optical region by the CVD method (FIGS. 5A and 5B).
Thereafter, the entire surface is etched by reactive ion etching to leave the silicon nitride film only on the side wall of the opening T, thereby forming the reflective film 50S (FIGS. 6A and 6B). Here, the silicon nitride film acts as a reflective film due to the refractive index difference between the acrylic resin and the silicon nitride.
Thereafter, as shown in FIGS. 7A and 7B, a resist mask (not shown) other than the region where the green color filter 50G is formed in the opening T whose side wall is covered with the reflective film 50S. And filled with a green color filter.
Further, as shown in FIGS. 8A and 8B, a resist mask (not shown) is formed in a region other than the region where the red color filter 50R is formed in the opening T whose side wall is covered with the reflective film 50S. Then, a red color filter is filled, and then a resist mask (not shown) is formed in the opening T whose side wall is covered with the reflective film 50S except for the region where the blue color filter 50B is to be formed. Fill with color filter.

  In this way, the color filter that easily surrounds the color filters of the respective colors with the white pixels surrounded by the reflective film 50S is easily formed with the translucent region as the white pixel 50W.

(Embodiment 3)
9 is a schematic cross-sectional explanatory view of a solid-state imaging device using a color filter according to Embodiment 3 of the present invention, FIG. 10 is a cross-sectional view, and FIG. 11 is a schematic plan view (FIG. 10 is an A- (A line cross-sectional schematic diagram). 12A and 12B are schematic diagrams for explaining this color filter (FIG. 12A is a cross-sectional view taken along the line BB of FIG. 12B), and FIGS. 13 to 17 are diagrams of the solid-state imaging device. It is process sectional drawing which shows the manufacturing process of a color filter.
As shown in FIG. 9, in this solid-state imaging device, a color filter for each color is disposed above a photodiode 30 via a frame-like translucent region 50T whose side wall is covered with a reflective film 50S. 50R, 50G, and 50B are formed so as to be separated from each other. Here, the translucent region 50T constitutes a white pixel, and the reflective film 50S is formed on the side wall of the recess formed in the white pixel. The color filter material for each color is formed with a reflective film on the side wall of the recess formed in the resin film constituting the translucent region 50T so as to face each photodiode 30, and each color filter for each color is formed in this opening. The material is filled to form a red color filter 50R, a green color filter 50G, and a blue color filter 50B as first to third color filters. Here, as the resin film constituting the translucent region 50T, a resist material having translucency with respect to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.) or thermosetting (non-photosensitive). Use materials. Further, a tungsten film is used as the reflective film 50S, but other metal films such as aluminum may be used. High-precision first to third opening patterns patterned by photolithography or dry etching are arranged in the light-transmitting region 50T. As shown in FIG. 10 and FIG. 11, the color filter includes a red color filter 50R, a green color filter 50G, and a blue color filter 50B that correspond to the photodiodes 30, respectively. It is characterized in that each pattern edge is formed to be vertical on the chemical film 74 and the surface is a flat surface. In FIG. 11, reference numerals (R, G, B) indicating the color filters formed above the photodiodes 30 are attached to the photodiodes 30.

  FIGS. 12A and 12B schematically show color filters. Fig.12 (a) is BB sectional drawing of FIG.12 (b). The translucent region 50T constituting the white pixel is patterned with high accuracy by dry etching, a tungsten film is formed in the opening, and the flat portion is removed by anisotropic etching, and is left only on the sidewall of the opening. The color filter material formed in the opening whose side wall is covered with the reflective film 50S may not have photosensitivity. In that case, the color material is filled with high density, and the pattern edge can be formed to be vertical.

  Others have a usual structure, but photodiodes 30 as photoelectric conversion portions are arrayed on the surface portion of the n-type silicon substrate 1, and signal charges generated in the photodiodes 30 are arranged in the column direction (in FIG. 11). 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. 11) 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. 10, 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 flat under filter made of a translucent resin or the like. It is a film. 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 microlens 60, an on-filter planarizing film 61 made of an insulating translucent 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 is formed by spin 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 that is transparent to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.) or the like is used in the same manner as the light-transmitting region.

  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.

Next, the color filter manufacturing process 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, the lower layer than the insulating film 72 is omitted.

  First, as shown in FIG. 13A, a passivation film 73 made of a silicon nitride film is formed on the insulating film (BPSG) 72 by a plasma CVD method, and FIG. 13B is formed on the passivation film 73. As shown, a resin film for forming the translucent region 50T is formed by a coating method.

  Then, as shown in FIG. 13C, a resist pattern R1 is formed by photolithography. Thereafter, as shown in FIG. 13D, a first opening O1 is formed by reactive ion etching (RIE) using the resist pattern R1 as a mask.

  Next, as shown in FIG. 14A, a tungsten film 50S is formed by PVD, and by anisotropic etching, a tungsten film is formed only on the side wall of the first opening O1 as shown in FIG. 14B. Let it remain to form a reflective film.

  Then, a blue color filter material is applied as a first color filter material so as to have a film thickness of 0.5 to 2.0 μm. This color filter material has no photosensitivity. By this step, the blue color filter material is filled into the first opening O1 covered with the tungsten film 50S as the reflective film. In this state, the blue color filter material pattern is cured by heat treatment and ultraviolet irradiation (FIG. 14C), and planarized by CMP to form a blue color filter 50B (FIG. 14 (FIG. 14 (c)). d)).

  Thereafter, as shown in FIG. 15A, 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. 15B, 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.

  Thereafter, as shown in FIG. 15C, a tungsten film 50S is formed by the PVD method, and the tungsten film is left only on the side wall of the second opening O2 by anisotropic etching to form a reflective film.

Then, the red color filter material R is applied so as to have 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.
Thereafter, CMP is performed to flatten the surface, and a red color filter 50R is formed (FIG. 16A).

  Thereafter, as shown in FIG. 16B, 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. Here, in FIG. 16B and subsequent figures, it is assumed that a surface shifted to the left of the paper surface with respect to FIG.

  Thereafter, as shown in FIG. 16C, 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.

  Next, as shown in FIG. 16D, a tungsten film 50S is formed by the PVD method, and the tungsten film is left only on the sidewall of the third opening O3 by anisotropic etching to form a reflective film.

Then, a green color filter material 50G (G) is applied, and the green color filter material pattern is cured by heat treatment and ultraviolet irradiation (FIG. 17A).
Thereafter, CMP is performed to flatten the surface to form a green color filter 50G (FIG. 17B).

  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, a planarizing film 61 is formed on the color filter by applying a resist material that is transparent to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.). Thereafter, a microlens 60 is formed on the planarizing film 61 by an etching method, a melt method, or the like (FIG. 17C), thereby forming a solid-state imaging device as shown in FIG.

As described above, since the translucent region 50T whose side wall is covered with the reflective film 50S exists between the adjacent color filters, the sensitivity can be improved and the occurrence of color mixing can be ensured. Can be prevented. In addition, according to the manufacturing method of the present embodiment, openings are formed by dry etching using a resist pattern formed by photolithography as a mask on the resin film that becomes the translucent region 50T, and sequentially filled with color filter materials. Therefore, since the photosensitivity is unnecessary as the color filter material, a thinner color filter 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, the margin for obliquely incident light is widened, and the reflective film prevents the transmitted light from the adjacent color filters from entering, so that a solid-state imaging device with less shading can be manufactured. Become.
Note that this opening may be formed not only for each color but for three colors at once, and a reflective film may also be formed for filling each color filter sequentially.

  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 a dye-based color filter material, there is a problem of dye bleeding, but according to the present invention, since the color filters of each color are separated by the translucent region, it is possible to reliably prevent bleeding. it can.

  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 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.

  In the above-described embodiment, the reflective film 50S is formed in the concave portion formed in the translucent region 50T constituting the white pixel. However, instead of the reflective film 50S made of metal such as tungsten, the reflective film 50S is used. You may comprise with a low refractive index film | membrane or a multilayer film so that it may be confine | sealed so that light may not permeate | transmit.

(Embodiment 4)
Next, a solid-state imaging element according to Embodiment 4 of the present invention will be described.
As shown in FIG. 18, the fourth embodiment is characterized by a structure in which only the upper edge portion of the side wall of the recess formed in the translucent region 50T constituting the white pixel is filled with the reflective film 50S. Since others are the same as those of the third embodiment, description thereof is omitted.
With this configuration, more light can be taken in and color mixing can be prevented.

(Embodiment 5)
Next, a solid-state imaging element according to Embodiment 5 of the present invention will be described.
As shown in FIG. 19, the fifth embodiment is characterized in that the reflective film 50S is filled only in the lower part of the side wall of the recess formed in the translucent region 50T constituting the white pixel. Since others are the same as those of the third embodiment, description thereof is omitted.
With this configuration, more light can be taken in and color mixing can be prevented.

(Embodiment 6)
Next, a solid-state imaging element according to Embodiment 6 of the present invention will be described.
In the sixth embodiment, as shown in FIG. 20, the color filter layer (50G, 50B,) 50R is made reflective in the recess formed in the translucent region 50T constituting the white pixel, as in the third embodiment. It is characterized by the structure filled through the film 50S. Others are the same as those in the third embodiment, and a description thereof will be omitted.

  At the time of manufacturing, the light-transmitting region 50T is formed, and when the concave portion for forming the color filter is formed by photolithography, it is formed by etching so as to leave a part of the lower layer. The rest is the same as in the third embodiment.

(Embodiment 7)
Next, a solid-state imaging element according to Embodiment 7 of the present invention will be described.
As shown in FIG. 21, the seventh embodiment is characterized in that the upper layer of the color filter layer (50G, 50B,) 50R is also covered with the light-transmitting region 50T. Since others are the same as those of the third embodiment, description thereof is omitted.

  By this method, after forming a color filter of one color, the side wall is covered with a reflective film, covered with a light-transmitting film made of a light-transmitting material, and then the light transmitting portion of the color filter to be formed next Since the filter can be formed by repeating the process of forming openings in the conductive film, the color filters do not come into contact with each other during the forming step, so that color mixing due to elution and mixing of dyes can be prevented.

In addition, you may use the following processes, without being limited to the said method.
First, a translucent film is formed, and all of the first to third color filter openings are formed by dry etching or photolithography.

  Next, a tungsten film 50S is formed by the PVD method, and the tungsten film is left only on the side wall of the opening by anisotropic etching to form a reflective film. After covering the side wall of the opening with the reflective film in this manner, a first color filter film is formed and patterned by photolithography, leaving the first color filter only in the opening for the first color filter. Further, a light-transmitting film is further formed thereon and patterned by photolithography to leave the light-transmitting film on at least the first color filter. Similarly, a second color filter and a translucent film are formed thereon. Next, a third color filter is formed in the same manner, and finally an upper planarizing film (translucent film) is formed.

  Also by this method, after forming a color filter of one color, it is covered with a reflective film 50S, and then covered with a light-transmitting film made of a light-transmitting material. Since the filter can be formed by repeating the process of forming openings in the conductive film, the color filters do not come into contact with each other during the forming step, so that color mixing due to elution and mixing of dyes can be prevented.

(Embodiment 8)
As shown in FIG. 22, this embodiment is characterized in that the edge of the color filter is not a vertical surface but a tapered surface, and the others are the same as those of the color filter of the sixth embodiment.
Here, in the solid-state imaging device, the first and second color filters form a tapered surface whose width or diameter decreases as the photoelectric conversion unit is approached.
With this configuration, it is possible to provide a solid-state imaging device with improved light collecting properties and high reliability.

(Embodiment 9)
In the present embodiment, as shown in FIG. 23, a part of translucent region 50T made of the translucent material in the color filter of the seventh embodiment shown in FIG. 21 forms a lens surface. The other features are the same as in the fifth embodiment.
In manufacturing, after covering the color filter with a translucent material, a trench is formed only on the upper surface of the translucent material, the edge of the groove is rounded by reflow, and a lens surface is formed by performing etch back By doing so, a lens can be easily formed. According to this structure, since a lens and a translucent material are integrated, thickness reduction can be achieved.

  According to this configuration, since it is possible to form a thin color filter layer with high sensitivity and preventing color mixing, it is possible to further reduce the thickness, and it is useful as a solid-state imaging device in an electronic device such as a portable terminal.

Schematic diagram showing the structure of the color filter according to the first embodiment of the present invention. The figure which shows the manufacturing process of the color filter of Embodiment 1 of this invention. The figure which shows the manufacturing process of the color filter of Embodiment 1 of this invention. The figure which shows the manufacturing process of the color filter of Embodiment 1 of this invention. The figure which shows the manufacturing process of the color filter of Embodiment 2 of this invention. The figure which shows the manufacturing process of the color filter of Embodiment 3 of this invention. The figure which shows the manufacturing process of the color filter of Embodiment 3 of this invention. The figure which shows the manufacturing process of the color filter of Embodiment 3 of this invention. Schematic sectional view of a color filter according to a third embodiment of the present invention. Cross-sectional schematic diagram of a solid-state imaging device according to Embodiment 3 of the present invention 10 is a schematic plan view of FIG. Schematic diagram showing the structure of the color filter of the third embodiment The figure which shows the manufacturing process of the color filter of this Embodiment 3. The figure which shows the manufacturing process of the color filter of this Embodiment 3. The figure which shows the manufacturing process of the color filter of this Embodiment 3. The figure which shows the manufacturing process of the color filter of this Embodiment 3. The figure which shows the manufacturing process of the color filter of this Embodiment 3. Sectional schematic diagram of the color filter of Embodiment 4 of the present invention Schematic sectional view of a color filter according to a fifth embodiment of the present invention. Sectional schematic of the color filter of Embodiment 6 of this invention Schematic sectional view of a color filter according to a seventh embodiment of the present invention. Schematic sectional view of a color filter according to an eighth embodiment of the present invention. Schematic sectional view of a color filter according to a ninth embodiment of the present invention.

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 film 50S Reflective films 50B, 50R, 50G Color filter 50T Translucent region

Claims (28)

A color filter that is arranged to face each of a plurality of photoelectric conversion regions constituting a pixel and separates light incident on the photoelectric conversion region for each pixel,
The color filter is
The first color is different from the first color filter that fills the light-transmitting region that constitutes the white pixel and the concave portion formed in the light-transmitting region and selectively transmits the first color. A color filter comprising: a second color filter that selectively transmits the second color. The color filter according to claim 1,
A color filter in which a side wall of the inner wall of the concave portion of the translucent region is covered with a reflective layer. The color filter according to claim 2,
The reflective layer is a color filter that is a reflective metal layer. The color filter according to claim 2,
The reflective layer has a predetermined refractive index difference with respect to the translucent region, and is formed so that incident light can be reflected at an interface between the reflective layer and the translucent region. filter. The color filter according to claim 2,
The reflective layer is a multi-layer film, and is a color filter formed so that incident light can be reflected at an interface between the reflective layer and the translucent region. The color filter according to any one of claims 1 to 5,
The reflective layer is a color filter formed through an adhesive film that covers the translucent region constituting the inner wall of the recess. The color filter according to any one of claims 1 to 6,
A color filter having a protective layer integrally formed so as to cover the inner wall of the recess so as to cover the reflective layer. The color filter according to any one of claims 1 to 7,
The color filter in which the translucent region is composed of a translucent resin layer formed on the photoelectric conversion region. The color filter according to any one of claims 1 to 8,
The color filter is a color filter formed on the upper layer of the photoelectric conversion unit via a planarizing film. The color filter according to any one of claims 1 to 7,
The translucent region is a planarization film formed in an upper layer of the photoelectric conversion portion;
A color filter in which the recess is formed in the planarizing film. The color filter according to any one of claims 1 to 10,
The reflective layer is a color filter formed so as to cover the entire side wall. The color filter according to any one of claims 1 to 10,
The reflective layer is a color filter formed so as to cover an upper edge portion of the side wall. The color filter according to claim 11 or 12,
The first and second color filters constitute a tapered surface whose width or diameter decreases as the photoelectric conversion unit is approached. The color filter according to any one of claims 1 to 13,
The color filter further includes a third color filter that selectively transmits a third color. The color filter according to any one of claims 1 to 14,
The color filter is a color filter configured such that the white pixel and the first to third color filters formed of the light-transmitting region have different areas for each color. The color filter according to any one of claims 1 to 15,
The color filter is a color filter in which an area ratio between the translucent region and the color filter is different between a peripheral portion and a central portion. A color filter according to any one of claims 1 to 16,
Peripheral circuit unit including a photoelectric conversion unit including a plurality of photoelectric conversion regions constituting a pixel, a charge transfer unit that transfers charges generated in the photoelectric conversion unit, and a wiring layer connected to the charge transfer unit And a solid-state image sensor formed by forming the color filter on at least the upper layer of the photoelectric conversion unit. 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 translucent film to be a translucent region as a white pixel surrounding the color filter of each color on the substrate surface;
Forming an opening for forming a color filter in the translucent film;
And a step of filling the opening with a color filter material. The method for producing a color filter according to claim 18,
Prior to the step of filling the color filter material,
A color filter manufacturing method including a step of forming a reflective film so as to cover a side wall of the opening. A method for producing a color filter according to claim 18 or 19,
The step of forming the opening includes
A method of manufacturing a color filter, which is a step of forming an opening so as to leave a part of the translucent film at the bottom of the opening. The method for producing a color filter according to claim 20,
The step of forming the reflective film includes
Forming a reflective film on the substrate surface in which the opening is formed;
And a step of leaving the reflective film only on the side wall by anisotropic etching. The method for producing a color filter according to claim 21,
Prior to the step of forming the reflective film,
A method for producing a color filter, comprising a step of forming an adhesive film on the surface of the substrate in which the opening is formed. A white pixel formed of a light-transmitting region, a first color filter constituting a first color filter, and a second color filter different from the first color are formed on the surface of the substrate. A method of manufacturing a color filter formed by arranging two color filters,
Forming a color filter pattern in which the first color filter and the second color filter are spaced apart from each other on the surface of the substrate;
A translucent material that forms a translucent region so as to cover the color filter pattern of each color so that the first color filter and the second color filter are separated via the translucent region as a white pixel Forming the color filter. It is a manufacturing method of the color filter of Claim 23, Comprising:
After the step of forming the color filter pattern, including a step of forming a reflective film on the side wall of the color filter,
The step of forming the translucent material is a step of forming a translucent material for forming a translucent region so as to cover the pattern of the color filter having a reflective film formed on a side wall. Method. Peripheral circuit unit including a photoelectric conversion unit including a plurality of photoelectric conversion regions constituting a pixel, a charge transfer unit that transfers charges generated in the photoelectric conversion unit, and a wiring layer connected to the charge transfer unit On the surface of the substrate on which
Forming a color filter pattern in which the first color filter and the second color filter are arranged on the substrate surface so as to be separated from each other through a light-transmitting region as a white pixel;
Forming a translucent material that forms a translucent region so as to cover the pattern. It is a manufacturing method of the solid-state image sensing device according to claim 25,
After the step of forming the color filter pattern, including a step of forming a reflective film on the side wall of the color filter,
The step of forming the translucent material is a step of forming a translucent material that forms a translucent region so as to cover the pattern of the color filter having a reflective film formed on a side wall. Production method. Peripheral circuit unit including a photoelectric conversion unit including a plurality of photoelectric conversion regions constituting a pixel, a charge transfer unit that transfers charges generated in the photoelectric conversion unit, and a wiring layer connected to the charge transfer unit A solid-state imaging device manufacturing method for forming a color filter on the surface of the substrate formed with
Forming a first color filter on the surface of the substrate;
Forming an opening for forming a second color filter so as to leave a translucent region as a white pixel in the translucent material by forming a translucent material in the upper layer;
Forming a second color filter pattern in which the second color filter and the first color filter are arranged so as to be separated from each other in the opening;
Forming a translucent material that forms a translucent region so as to cover a color filter pattern of each color. It is a manufacturing method of the solid-state image sensing device according to claim 27,
A method of manufacturing a solid-state imaging device including a step of forming a reflective film on a side wall of the opening before the step of forming the color filter pattern after the opening is formed.

Images