JPH11354763A - Solid state image sensor and fabrication of color filter array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fabrication method of color filter array in which deterioration in the characteristics of a color filter can be suppressed by improving a situation where a color resist composing other color filter is left in a region surrounded by color filters arranged in checkered pattern. SOLUTION: Blue color filters B are formed in matrix by a blue color resist layer on a silicon dioxide film 2 and red color filters R are formed thereon by a red color resist layer while being shifted from the blue color filters B. Subsequently, green color filters G1, G2 are formed by a green color resist layer in checkered pattern in a region surrounded by the blue color filters B and the red color filters R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device and a method of manufacturing a color filter array, and more particularly to a solid-state image pickup device having a color filter array using a pigment-dispersed colored resist and a method of manufacturing the color filter array. About.

[0002]

2. Description of the Related Art A color filter array using a pigment-dispersed colored color resist has the advantage that the production cost can be reduced while ensuring color reproducibility, as compared with, for example, a conventionally used dyed color filter array. have. Due to such advantages, it is expected that the device will be widely used in solid-state imaging devices such as CCD linear / area image sensors in the future.

At present, various studies are being conducted on what kind of manufacturing method can be used to improve the productivity of a color filter array using a pigment-dispersed colored color resist. An example of the studied manufacturing method is regarded as a conventional technique of the present invention, and will be described below.

FIG. 11A is an enlarged plan view showing a part of a color filter array having a Bayer array.
1B is a cross-sectional view taken along line 11B-11B in FIG.

As shown in FIGS. 11A and 11B, in the Bayer arrangement, color filters G1 and G2 (each of which is green) for extracting a luminance signal requiring high resolution are arranged in a checkered pattern. A color filter B (blue) and a color filter R (red) for extracting the other two types of color signals that do not require relatively high resolution are arranged in the remaining portion.

The color filters "G1" and "G"
2 "," B ", and" R "are the silicon substrate 101, respectively.
It is often formed on the silicon dioxide film 102 formed thereon via an acrylic transparent resin layer (not shown). A light-shielding film 103 is formed in the silicon dioxide film 102. The light-shielding film 103 includes a color filter "G1",
An opening 104 for transmitting light is provided corresponding to a portion below “G2”, “B”, and “R”. Opening 104
Pixels 105 are formed one by one in the substrate 101 located below the pixel 105. The portion indicated by reference numeral 106 is a vertical transfer stage, which sequentially transfers color signals or luminance signals obtained by the pixels 105 to a horizontal transfer stage (not shown).

Color filter G in Bayer array
1 and G2, it is important that the rows of the color filters G1 and the rows of the color filters G2 are formed so that there is no difference in film thickness in order to make the spectral sensitivity equal to each other. For this purpose, it has been considered that the color filters G1 and G2 are formed of a first-layer pigment-dispersed color resist applied first. By forming the color filters G1 and G2 with the first-layer pigment-dispersed color resist having no step, it is considered that a difference in film thickness between the row of the color filters G1 and the row of the color filters G2 is unlikely to occur. It was because it was done.

FIGS. 12 to 17 are perspective views for explaining a method of manufacturing a color filter array having a Bayer array. 12 to 17 correspond to the portions indicated by the dashed line frame XII in FIG.

First, as shown in FIG. 12, a green color resist in which a green pigment is dispersed is applied on the silicon dioxide film 102 to form a green color resist layer 111 (first color resist). Next, the green color resist layer 111 is exposed to obtain insoluble portions 111-G1 and 111-G2 which are insoluble in a developing solution corresponding to the formation pattern of the color filters G1 and G2 formed in a checkered pattern.

Next, as shown in FIG. 13, by developing the green color resist layer 111, the color filters G1, G arranged in a checkered pattern on the silicon dioxide film 102 are formed.
Get 2.

Next, as shown in FIG. 14, a blue color resist in which a blue pigment is dispersed is applied on the structure shown in FIG. 13 to form a blue color resist layer 112 (second color resist). . Next, the blue color resist layer 112 is exposed to obtain insoluble portions 112-B corresponding to the formation pattern of the color filters B formed in a matrix at portions where the color filters G1 and G2 are not formed.

Next, as shown in FIG. 15, by developing the blue color resist layer 112, the color filters B arranged in a matrix on the silicon dioxide film 102 are formed.
Get.

Next, as shown in FIG. 16, a red color resist in which a red pigment is dispersed is applied on the structure shown in FIG. 15 to form a red color resist layer 113 (third layer color resist). . Next, the red color resist layer 113 is exposed to light, and insoluble portions 113-R corresponding to the formation pattern of the color filters R formed in a matrix at the portions where the color filters G1, G2, and B are not formed.
Get.

Next, as shown in FIG. 17, by developing the red color resist layer 113, the color filters R arranged in a matrix on the silicon dioxide film 102 are formed.
Get.

As described above, the green color resist layer 111
Is formed in the first layer, so that the color filter G1 is formed.
A difference in film thickness between the color filter G2 and the color filter G2 can be suppressed.
Can form a color filter array having a high-quality Bayer array in which spectral sensitivities can be made substantially equal to each other.

However, in the above manufacturing method, FIG.
The first-layer color resist, that is, the green color resist layer 111 that has been exposed as shown in FIG.
When the development is performed as shown in FIG. 5, a "residue" of the first layer color resist, that is, a green color resist is generated in a region A surrounded by the color filters G1 and G2 as shown by oblique lines in the drawing. This is presumably because the four sides of the area A are surrounded by the green color filters G1 and G2, and the developer does not sufficiently spread.

[0017]

As described above, when the "residue" of the green color resist 111 is generated in the region A, the green color resist is taken into the color filters B and R formed here. Would. For this reason, the characteristics of the color filter B and the color filter R deteriorate, and as a color filter array,
It becomes difficult to obtain sufficient characteristics.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a color filter array using a pigment-dispersed colored resist in a region surrounded by color filters arranged in a checkered pattern. It is an object of the present invention to provide a method of manufacturing a color filter array which can improve the situation in which a color resist remains and suppress deterioration of the characteristics of a color filter.

Another object of the present invention is to provide a solid-state imaging device having a color filter array capable of improving the flatness of a flattening layer formed above the color filter array.

[0020]

In order to achieve the above object, according to the present invention, a color filter array forming surface is provided with a first
Forming a first color resist layer in which pigments of the following colors are dispersed, patterning the first color resist layer, and forming a matrix-shaped first color resist layer on the color filter array forming surface.
Are formed, and the matrix-shaped first color filter group is formed.
Forming a second color resist layer in which a pigment of a second color is dispersed on the color filter array forming surface on which the color filter group is formed; patterning the second color resist layer; On the array forming surface,
The second color filter group in a matrix is formed so as to be shifted from the first color filter group in the matrix. Thereafter, a third color resist layer in which a third color pigment is dispersed is formed on the color filter array forming surface on which the first and second color filter groups in the matrix are formed. Patterning the third color resist layer, and forming a checkered third color filter group in a region surrounded by the matrix first and second color filter groups on the color filter array forming surface. It is characterized by.

According to the invention having the above configuration, the third checker-like color filter group is formed after forming the first and second color filter groups. For this reason, when forming the first color filter group, there is no region in which the four sides are surrounded by insoluble portions. That is, the patterning of the first color resist layer is easy, and there is almost no situation that "residue" of the first color resist layer is generated.

Similarly, when forming the second color filter group, there is no area in which the four sides are surrounded by insoluble portions. That is, the patterning of the second color resist layer is easy, and the situation that "residue" of the second color resist layer is almost eliminated.

Further, a third color resist layer 1 in a checkered pattern is provided.
In the formation of No. 3, there is a region which is surrounded on all sides by insoluble portions, and this region is above the first and second color filter groups. That is, the position is higher than the insoluble portion. For this reason, the patterning is facilitated as compared with the case where the position of the region surrounded on all sides by the insoluble portion is at the same height as the position of the insoluble portion, and the first and second color filter groups can be "Residue" of the third color resist layer hardly occurs.

Therefore, the possibility that the third color resist is taken into the first and second color filter groups is reduced, and the characteristics of the color filter array can be improved.

According to another aspect of the present invention, there is provided a color filter group of a first color having a thickness of t1, formed on a color filter array forming surface of an apparatus.
The second color filter group of the second color and the third color filter group of the thickness t3
A solid-state imaging device having a color filter array composed of a group of color filters having the following thicknesses:
t2 and t3 have a relationship of t1 ≦ t2 ≦ t3, the third color filter group having the thickness t3 is arranged in a checkered pattern on the color filter forming surface, and the third color filter group in the horizontal direction of the color filter array is arranged. It is characterized in that it is arranged in all the columns and vertical columns.

According to the invention having the above-described structure, the third color filter group having the same thickness or the thickest color filters is arranged in a checkered pattern, and the horizontal rows and the vertical directions of the color filter array are arranged. , The flatness of the flattening layer formed above the color filter array can be improved.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1A is an enlarged plan view showing a part of a color filter array having a Bayer array manufactured using a manufacturing method according to a first embodiment of the present invention. 1 (B) is a cross-sectional view taken along line 1B-1B in FIG. 1 (A).

As shown in FIGS. 1A and 1B, the Bayer array has green color filters G1 and G2 (green respectively) for extracting a luminance signal requiring high resolution.
Are arranged in a checkered pattern (checkered pattern), and a blue color filter B and a red color filter R for extracting the other two types of color signals that do not require relatively high resolution are arranged in the remaining portion.

The color filters "G1" and "G"
The color filters 2 "," B ", and" R "are often formed on the silicon dioxide film 2 formed on the silicon substrate 1 via an acrylic transparent resin layer (not shown). The size of each of “G1”, “G2”, “B”, and “R” is, for example, a square having a side of about 3 μm to 5 μm. 3 are color filters “G1”, “G
2 "," B "and" R ", respectively,
It has an opening 4 for transmitting light. Pixels 5 are formed one by one in the substrate 1 located below the opening 4. The pixel 5 is composed of, for example, a photodiode. The portion indicated by reference numeral 6 is a vertical transfer stage,
The color signals or the luminance signals obtained by the pixels 5 are sequentially transferred to a horizontal transfer stage (not shown). The vertical transfer stage 6 and the horizontal transfer stage (not shown) are constituted by, for example, a CCD.

Hereinafter, the manufacturing method will be described with reference to FIGS. 2 to 7 are perspective views illustrating a method for manufacturing a color filter array having a Bayer array according to an embodiment of the present invention. 2 to 7 respectively correspond to the portions indicated by the dashed line frame II in FIG.

First, as shown in FIG. 2, the surface of the solid-state imaging device such as a CCD area / linear image sensor or the like on which a color filter array is formed, that is, on the silicon dioxide film 2,
Alternatively, a blue color resist in which a blue pigment is dispersed is applied on an acrylic transparent resin layer (not shown) to form a blue color resist layer 11 (first layer color resist). Next, the blue color resist layer 11 is exposed. In this embodiment, since a negative type color resist is used, a portion exposed to light becomes insoluble in the developing solution. Reference numerals 11-B correspond to insoluble portions, and correspond to the formation patterns of the blue color filters B formed in a matrix.

Next, as shown in FIG. 3, the blue color resist layer 11 is developed. Thus, blue color filters B arranged in a matrix on the silicon dioxide film 2 are formed.

Next, as shown in FIG. 4, the silicon dioxide film 2 in which the blue color filters B are arranged in a matrix.
A red color resist in which a red pigment is dispersed is applied thereon to form a red color resist layer 12 (second color resist). At this time, the red color resist has a thickness t2 at a portion where the red color filter is formed.
Is applied so as to be thicker than the thickness t1 of the blue color filter B. Next, the red color resist layer 12 is exposed. In this embodiment, since a negative color resist is used similarly to the blue color resist, a portion where light is applied becomes insoluble in the developing solution. The reference numerals 12-R are insoluble portions and correspond to the formation patterns of the red color filters R formed in a matrix. The insoluble portion 12-R is set in a region shifted from the blue color filter B and arranged in a checkered pattern with the formed red color filter R and blue color filter B.

Next, as shown in FIG. 5, the red color resist layer 12 is developed. Thus, on the silicon dioxide film 2, red color filters R arranged in a matrix shifted from the blue color filters B are formed.

Next, as shown in FIG. 6, a green color resist in which a green pigment is dispersed is applied on the silicon dioxide film 2 in which the blue color filters B and the red color filters R are arranged in a checkered pattern. Green color resist layer 13
(Third-layer color resist) is formed. At this time, the thickness t3 of the green color resist in the portion where the green color filter is formed is the thickness t3 of the red color filter R.
Apply so that it is thicker than 2. Next, the green color resist layer 13 is exposed. In this embodiment, a negative color resist is used similarly to the blue color resist and the red color resist, and therefore, the portion exposed to light becomes insoluble in the developing solution. Reference numerals 13-G1, 13-
The portions where G2 becomes insoluble correspond to the formation patterns of the green color filters G1 and G2 formed in a checkered pattern. The insoluble portions 13-G1 and 13-G2 are set in regions surrounded by the blue color filter B and the red color filter R, respectively.

Next, as shown in FIG. 7, the green color resist layer 13 is developed. As a result, green color filters G1 and G2 are formed on the silicon dioxide film 2 in a region surrounded by the blue color filter B and the red color filter R and arranged in a checkered pattern.

According to the above-described method for manufacturing a color filter array, checker-like green color filters G1 and G2 are used.
With a blue color filter B and a red color filter R
Is formed after each is formed.

When the blue color resist layer 11 is developed, there is no region surrounded on all sides by the insoluble portion 11-B. Therefore, development, that is, removal of the blue color resist layer 11 is easy, and
There are almost no circumstances that produce "residues".

Similarly, when the red color resist layer 12 is developed, there is no area surrounded on all sides by the insoluble portion 12-R, and the removal is easy. Further, when developing the green color resist layer 13, the four sides are insoluble portions 13-.
An area surrounded by G1, 13-G2 is generated. However, this region is on the blue color filter B and the red color filter R, and the insoluble portions 13-G1, 13
The position is higher than -G2. For this reason, FIG.
As shown in (B), insoluble portions 111-G1 on all sides,
Region A surrounded by 111-G2 and insoluble portion 11
The removal is easier than in the case where the positions of 1-G1 and 111-G2 are equal to each other. Therefore, “residues” of the green color resist hardly occur on the blue color filter B and the red color filter R.

Therefore, the possibility that the green color resist is taken in the blue color filter B and the red color filter R can be reduced, and the characteristics of the color filter array can be improved.

In the manufacturing method according to the first embodiment, the thickness of the blue color filter B is "t1", the thickness of the red color filter R is "t2", and the thickness of each of the green color filters G1 and G2. Assuming that the thickness is "t3", these color filters "B", "R", "G1", and "G2" are sequentially formed in order of decreasing thickness.

According to such a manufacturing method, the green color resist layer formed last has the largest thickness. In the color filter array in which the thicknesses of the green color filters G1 and G2 are the thickest, when the upper part of the color filter array is flattened by, for example, a colorless and transparent resist layer, the following advantages can be obtained. Can be.

FIG. 8A shows green color filters G1 and G1.
FIG. 8 is an enlarged plan view showing a part of the color filter array having the Bayer array, in which the thickness of the second color filter 2 is the thickest.
FIG. 8B is a sectional view taken along line 8B-8B in FIG.

As shown in FIGS. 8A and 8B, a colorless and transparent resist is provided above the color filter array constituted by the color filters "B", "R", "G1" and "G2". Covered by layer 14 and planarized.

At this time, in the color filter array in which the thicknesses of the green color filters G1 and G2 are the thickest, particularly, as shown in FIG. 8A, the thickest green color filters G1 and G2 are arranged in the vertical direction. Row V (V1 to V8)
And all of the horizontal rows H (H1 to H8). Therefore, the colorless and transparent resist layer 14 formed above the color filter array is easily flattened. Therefore, when the upper part of the color filter array is covered with the colorless and transparent resist layer 14, the flatness of the colorless and transparent resist layer 14 is improved, and the characteristics of the color filter array can be further improved.

On the other hand, in the color filter array shown in FIG. 11, the thickness of the red color filter R is the largest. This is shown in FIGS. 9A and 9B. FIG. 9 (A)
9B is an enlarged plan view showing a part of the color filter array having the Bayer arrangement in which the thickness of the red color filter R is the thickest, and FIG. 9B is 9B-9 in FIG. 9A.
It is sectional drawing which follows the B line.

As shown in FIG. 9A, in the color filter array having the thickest red color filter R, the thickest red color filter R is placed in the column V in the vertical direction.
(V1 to V8) and every other row H (H1 to H8) in the horizontal direction.

The thickest color filters as shown in FIGS. 8 (A) and 8 (B) are arranged in the vertical column V (V1) in comparison with the color filter arrays shown in FIGS. 9 (A) and 9 (B).
To V8) and all the horizontal rows H (H1 to H8) are more advantageous for flattening the colorless and transparent resist layer 14.

[Second Embodiment] FIG. 10A is an enlarged plan view showing a part of a color filter array having a Bayer array according to a second embodiment of the present invention.
FIG. 10B is a cross-sectional view taken along line 10B-10B in FIG.

As shown in FIG. 10, in the second embodiment, the thicknesses of the blue color filter B, the red color filter R, and the green color filters G1, G2 are made equal.

When the thicknesses of the blue color filter B, the red color filter R, and the green color filters G1 and G2 are made equal to each other, it is more advantageous to flatten the colorless and transparent resist layer 14.

As described above, the present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof.

For example, in the above-described embodiment, a basic Bayer array is shown as an example of an array of color filters.
There are several deformation patterns in the Bayer arrangement. The arrangement of the color filters may be a Bayer arrangement of these deformed patterns.

In the above embodiment, the red color filter R is formed after forming the blue color filter B. However, the blue color filter B may be formed after forming the red color filter R.

[0055]

As described above, according to the present invention, the situation where the color resist remains in the area surrounded by the color filters arranged in a checkered pattern is improved, and the color filter which can suppress the deterioration of the characteristics of the color filters can be suppressed. A method for manufacturing a filter array can be provided. Further, it is possible to provide a solid-state imaging device having a color filter array capable of improving the flatness of a flattening layer formed above the color filter array.

[Brief description of the drawings]

FIG. 1A is a plan view of a color filter array manufactured by a manufacturing method according to a first embodiment of the present invention, and FIG. 1B is a 1B-1B line in FIG. 1A. FIG.

FIG. 2 is a perspective view showing main manufacturing steps of the manufacturing method according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing main manufacturing steps of the manufacturing method according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing main manufacturing steps of the manufacturing method according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing main manufacturing steps of a manufacturing method according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing main manufacturing steps of the manufacturing method according to the first embodiment of the present invention.

FIG. 7 is a perspective view showing main manufacturing steps of the manufacturing method according to the first embodiment of the present invention.

8 is a plan view of a color filter array having a thickest green color filter, and FIG. 8B is a cross-sectional view taken along line 8B-8B in FIG. 8A.

9 is a plan view of a color filter array having the thickest red color filter, and FIG. 9B is a cross-sectional view taken along line 9B-9B in FIG. 9A.

FIG. 10A is a plan view of a color filter array according to a second embodiment of the present invention, and FIG. 10B is a sectional view taken along line 10B-10B in FIG. 10A.

11A is a plan view of a color filter array manufactured by a conventional manufacturing method, and FIG. 11B is a cross-sectional view taken along line 11B-11B in FIG. 11A.

FIG. 12 is a perspective view showing a manufacturing process of a conventional manufacturing method.

FIG. 13 is a perspective view showing a manufacturing process of a conventional manufacturing method.

FIG. 14 is a perspective view showing a manufacturing process of a conventional manufacturing method.

FIG. 15 is a perspective view showing a manufacturing process of a conventional manufacturing method.

FIG. 16 is a perspective view showing a manufacturing process of a conventional manufacturing method.

FIG. 17 is a perspective view showing a manufacturing process of a conventional manufacturing method.

18 (A) and 18 (B) are perspective views for explaining a conventional problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Silicon dioxide film, 3 ... Light shielding film, 4 ... Opening, 5 ... Pixel, 6 ... Vertical transfer stage, 11 ... Blue color resist layer, 12 ... Red color resist layer, 13 ... Green color resist layer 14: a colorless and transparent resist layer; B: a blue color filter; R: a red color filter; G1, G2: a green color filter.

Claims (5)

[Claims] 1. A color filter array including a first color filter group having a thickness of t1, a second color filter group having a thickness of t2, and a third color filter group having a thickness of t3. Wherein the thicknesses t1, t2, and t3 have a relationship of t1 ≦ t2 ≦ t3, and a third color filter group having the thickness t3 is in a checkered pattern on the color filter formation surface. Along with
A solid-state imaging device, wherein the color filter array is arranged in all the horizontal rows and the vertical rows. 2. forming a first color resist layer in which a pigment of a first color is dispersed on a color filter array forming surface; and patterning the first color resist layer to form the color filter array. Forming a matrix-shaped first color filter group on a surface; and dispersing a second color pigment on the color filter array formation surface on which the matrix-shaped first color filter group is formed. Forming a second color resist layer; patterning the second color resist layer; forming a matrix-shaped second color filter group on the color filter array formation surface; Forming the first and second color filter groups in a matrix, wherein the first and second color filter groups in the matrix are formed. Forming a third color resist layer in which a pigment of a third color is dispersed on a surface; patterning the third color resist layer; and forming a third checker-like pattern on the color filter array formation surface. Forming a color filter group in a region surrounded by the matrix of the first and second color filter groups. 3. The thickness t of the first color filter group
1, the thickness t2 of the second color filter group and the thickness t3 of the third color filter group are t1 <
3. The method according to claim 2, wherein a relationship of t2 <t3 is satisfied, and the first to third color filter groups are formed in order of decreasing thickness. 4. The first color filter group extracts a first color signal, the second color filter group extracts a second color signal, and the third color filter group extracts a luminance signal. The method for producing a color filter array according to claim 2, wherein the color filter array is extracted. 5. The method according to claim 2, wherein the first color is one of blue and red, the second color is the other of blue and red, and the third color is green. A method for manufacturing a color filter array according to claim 1.