JP2009049117A - Color filter forming method for solid-state image sensor, solid-state image sensor, and pattern mask set for solid-state image sensor - Google Patents

Abstract

Adhesion between adjacent filter layers is prevented to prevent deterioration in device characteristics of a solid-state imaging device, such as variations in color filter thickness and size of each filter layer, sensitivity reduction, color mixing, and sensitivity ratio deterioration. .
A color filter in which land-like filter layers are mixedly arranged in a different pattern for each color is patterned on a substrate P using unit color filter pattern masks GM, BM, RM, and WM that differ for each color. In the case of forming, the land-shaped filter layer G of the first color is patterned using the mask GM of the unit color filter pattern GP corresponding thereto, and then the land-shaped filter layers B and R for the second color and thereafter are formed. When forming between the filter layers G of the first color, the shapes of the mask openings 5 of the masks BM and RM for the second and subsequent colors are changed to the filter layers B of the unit color filter patterns BP and RP for the color, The shape is different from the land shape of R.
[Selection] Figure 1

Description

  The present invention relates to a color filter forming method for a solid-state image sensor, a solid-state image sensor, and a pattern mask set for a solid-state image sensor, and in particular, a technique for preventing fusion of land-like filter layers and obtaining excellent device characteristics. About.

  In general, a color filter used in a solid-state imaging device such as a CMOS or a CCD is formed by a photolithography exposure and development process using a three-color or four-color (or non-color) resist. A pattern is formed on the top (see, for example, Patent Document 1).

  FIG. 6 shows the arrangement of the filter layers (RGB) of the color filter 1 with the Bayer arrangement inclined by 45 °. When the arrangement of the filter layers is viewed from the lower left to the diagonal upper right in FIG. “R, G, R, G,...” Are arranged in a row, and “G, B, G, B,. Such a color filter 1 is formed, for example, as shown in FIG. That is, a red pattern in which a plurality of land-like red filter layers R are arranged on a substrate at a predetermined interval is formed by photolithography (FIG. 7A), and then on the substrate on which the red pattern is formed. A plurality of land-like blue filter layers B are arranged between the red filter layers R to form a blue pattern (FIG. 7B). Further, the green filter layer G is disposed in a region other than the region where the red filter layer R and the blue filter layer B are formed (FIG. 7C).

  Further, as shown in FIG. 8, a filter for luminance information is obtained in order to obtain color resolution that is not affected by color information and color reproducibility that is not influenced by spectral characteristics of luminance information by distinguishing and detecting color information and luminance information. A color filter 3 having a layer W is known. The color filter 3 is arranged with “W, G, W, G,...” In the odd rows and “R, W in the even rows when the filter layer arrangement is viewed from the lower left to the diagonal upper right in FIG. , B, W,..., The filter layer W is arranged in a checkered pattern, and the filter layers R, G, B are arranged in the remaining checkered positions.

The color filter 3 having the filter layer W is formed, for example, as shown in FIG. That is, a plurality of land-like green filter layers G are formed on the substrate (FIG. 9A), and a land-like blue filter layer B is formed between the green filter layers G (FIG. 9B). Further, after the land-like red filter layer R is formed between the green filter layer G and the green filter layer G (FIG. 9C), the green filter layer G, the blue filter layer B, and the green filter layer G are formed. The luminance information filter layer W is disposed in a region other than the region where the luminance information is formed (FIG. 9D).
JP-A-6-273611

  As shown in FIG. 7, the color filter 1 has no problem because the land-like red filter layer R is discrete in the formation of the red pattern, but when forming the subsequent blue pattern, the land-like blue filter The layer B is disposed between the land-shaped red filter layers R that are already formed so that the corners thereof are close to each other. For this reason, the space | interval of the red filter layer R and the blue filter layer B is narrow, and the bridge | bridging 2 may be formed by the fusion | melting by flowing in between red filter layer R and the blue filter layer B. The fusion of the filter layers described above causes variations in the thickness of the color filter and the size of each filter layer, and causes a decrease in device characteristics such as a decrease in sensitivity of the solid-state image sensor, color mixing, and a decrease in sensitivity ratio.

  Further, as shown in FIG. 9, when the color filter 3 having the filter layer W for luminance information is formed with the blue filter layer B and the red filter layer R, the land-like blue filter layer B is already formed. The red filter layer R is disposed between the land-shaped green filter layer G and the blue filter layer B that have already been formed. It arrange | positions so that the corners may adjoin. Therefore, as described above, the intervals between the filter layers G and B and the intervals between G, B, and R are narrow, and fusion occurs between the filter layers G and B and between G, B, and R, and the bridge 2 (2A 2B) may be formed.

  The above-described fusion of the filter layers R, G, and B is likely to occur more frequently as the number of pixels and the miniaturization of solid-state imaging devices in recent years further increase in pattern miniaturization. The

  The present invention has been made in view of the above-described circumstances, and prevents adjacent filter layers from fusing together, resulting in variations in the thickness of the color filter and the size of each filter layer, sensitivity reduction, color mixing, and sensitivity ratio. It is an object of the present invention to provide a method for forming a color filter of a solid-state image sensor, a solid-state image sensor, and a pattern mask set for the solid-state image sensor that can prevent deterioration of device characteristics of the solid-state image sensor such as deterioration.

The above object of the present invention can be achieved by the following configuration.
(1) A color filter in which land-like filter layers are mixedly arranged in different patterns for each color, and a mask having an opening based on a unit color filter pattern that differs for each color, and the land-like filter layers for each color are A method for forming a color filter of a solid-state imaging device that is formed by patterning on a substrate in color sequential order,
After the land-shaped filter layer of the first color is patterned on the substrate using a unit color filter pattern mask corresponding to the color of the first color,
When the land-like filter layer for the colors after the second color and before the final color is formed by patterning between the filter layers of the first color, the colors after the second color and before the final color A method of forming a color filter for a solid-state imaging device, wherein each of the openings of the mask is formed in a shape different from the land shape of each filter layer of the unit color filter pattern for the color.

  According to the color filter forming method of the solid-state imaging device, the land-like filter layer of the first color is patterned on the substrate using the unit color filter pattern mask corresponding to the color of the first color, and then When patterning the land-like filter layer for the colors after the second color and before the final color, each aperture shape of the mask for the colors after the second color and before the final color is a unit for that color. Since pattern formation is performed using a mask having a shape different from the land shape of each filter layer of the color filter pattern, even if a filter layer is newly formed between the filter layers of the first color, the filter layer Fusion of the outer edges is prevented, and a regular filter layer for the color can be formed on the substrate by patterning. Therefore, it is possible to prevent deterioration in device characteristics of the solid-state imaging device, such as variations in the thickness of the color filter and the size of each filter layer, reduction in sensitivity, color mixing, and deterioration in sensitivity ratio due to fusion of the outer edges of the filter layers. .

(2) A method for forming a color filter of a solid-state imaging device according to (1),
Each opening shape of the mask with respect to colors after the second color and before the final color has an opening outer edge on the side adjacent to each land-like filter layer already formed on the substrate inside the opening. A method for forming a color filter of a solid-state imaging device having an intrusive shape.

  According to this color filter forming method of the solid-state imaging device, each mask opening shape of the mask for the second and subsequent colors and up to the last color is adjacent to each land-like filter layer already formed on the substrate. Since the opening outer edge on the side has a shape entering the inside of the mask opening, it is possible to widen the interval between adjacent filter layers on the mask. As a result, it is possible to prevent the outer edges of the filter layer from being fused to each other due to inflow during patterning formation.

(3) A method for forming a color filter of a solid-state imaging device according to (1) or (2),
The color filter includes a chromaticity filter for detecting color information and a luminance filter for measuring luminance information respectively arranged on the light incident side of the plurality of photodiodes, and arranged in a checkered pattern among the plurality of photodiodes. The chromaticity filter is arranged for the photodiodes arranged, and the luminance filter is arranged for the remaining checkered photodiodes where the chromaticity filters are not arranged,
A method for forming a color filter of a solid-state imaging device, wherein a filter layer for the chromaticity filter is formed in color sequential order, and then a filter layer for the luminance filter is formed.

  According to this method for forming a color filter of a solid-state imaging device, the color filter includes a chromaticity filter for detecting color information and a luminance filter for measuring luminance information, and the chromaticity filter is arranged on the checkered photodiodes. Even if the luminance filter is arranged on the remaining photodiodes arranged in a checkered pattern where no chromaticity filter is arranged, even if other filter layers are present in the proximity of the patterning Further, fusion of the outer edges of the filter layer due to inflow during patterning is prevented.

(4) A method for forming a color filter of a solid-state imaging device according to (1) or (2),
In the color filter, green, blue, and red filter layers are arranged on the light incident sides of a plurality of photodiodes, respectively, and a filter layer for green is formed after forming a filter layer for blue and red A method for forming a color filter of an element.

  According to the color filter forming method of the solid-state imaging device, the green, blue, and red filter layers are arranged in a Bayer arrangement (or an arrangement in which the filter layers are inclined by 45 °), and the red and blue filter layers are formed. Since the green filter layer is formed, when the blue filter layer is formed, even if the already formed red filter layer is close to the filter layer, the filter layer is caused by inflow during patterning formation. Fusion of the outer edges of each other is prevented.

(5) a plurality of light receiving sections for detecting light;
A color filter disposed on an incident light side of the light receiving unit;
An output unit for outputting a light reception signal from the light receiving unit;
A solid-state imaging device comprising:
A solid-state imaging device, wherein the color filter is formed using the color filter forming method according to any one of (1) to (4).

  According to the solid-state imaging device, the light receiving unit includes a plurality of light receiving units that detect light and an output unit that outputs a light reception signal from the light receiving unit, and the color filter having no fusion between the outer edges of adjacent filter layers. Therefore, there is no reduction in sensitivity, color mixing, deterioration in sensitivity ratio, and the like due to the fusion of the filter layers, and excellent device characteristics can be obtained.

(6) A pattern mask set for a solid-state imaging device for forming a color filter having a different pattern for each color in color sequence,
Solid imaging in which at least a part of the pattern mask has a shape corresponding to the pattern at least a part of the part adjacent to the pattern of another color, and the edge of the pattern is recessed inward. Pattern mask set for elements.

  According to the pattern mask set for a solid-state imaging device, fusion with other adjacent patterns can be prevented by forming the pattern edge so as to be recessed inward.

(7) The pattern mask set for a solid-state imaging device according to (6),
The at least part of the pattern mask is an N-th pattern mask for patterning from at least the second to N-1 among N (N is an integer of 1 or more) pattern masks;
The pattern mask set for a solid-state imaging device, wherein the pattern of the other color is the pattern that has already been patterned.

  According to this pattern mask set for a solid-state image sensor, the edge is recessed with respect to at least the second to (N-1) th pattern masks for patterning among N (N is an integer of 1 or more) pattern masks. Thus, fusion with the already patterned pattern is prevented.

  According to the color filter forming method, solid-state image sensor, and solid-state image sensor pattern mask set of the present invention, the outer edges of adjacent filter layers are prevented from being fused to each other, and the filter layers are fused. Therefore, there is no variation in the thickness of the color filter and the size of each filter layer, and a color filter having stable performance can be formed. In addition, a solid-state imaging device having excellent device characteristics can be manufactured without a decrease in sensitivity, color mixing, or deterioration in sensitivity ratio.

Hereinafter, preferred embodiments of a color filter according to the present invention will be described in detail with reference to the drawings.
First, as an example of a color filter according to the present embodiment, a color filter having filter layers R, G, and B for color information and a filter layer W for luminance information and capable of detecting color information and luminance information separately. Will be described. FIG. 1 is a conceptual diagram showing a process of sequentially patterning a land-like filter layer on a substrate using a mask of a unit color filter pattern different for each color. The upper part of FIG. 1 represents the mask shape, and the lower part schematically represents the arrangement of the filter layers as a result of the mask exposure.

  As shown in FIG. 1, a color filter 100 having land filter layers R, G, and B for color information and a land filter layer W for luminance information includes a mask GM having a green filter pattern GP, Using the mask BM having the blue filter pattern BP, the mask RM having the red filter pattern RP, and the mask WM having the luminance information filter pattern WP, each filter layer G, B, R, W , In that order, formed on the substrate P by photolithography.

  Specifically, first, a green filter pattern GP formed on the mask GM is exposed and transferred onto the substrate P using the mask GM, thereby forming a land-like green filter layer G. The openings 4 of the green filter pattern GP formed on the mask GM are arranged at a predetermined interval from each other, and the shape of the opening outer edge 4a is that of the green filter layer G to be exposed and transferred to the substrate P. It is formed in substantially the same shape as the shape. Thereby, land-like green filter layers G are discretely formed on the substrate P.

  Next, on the substrate P on which the green filter layer G is formed, the blue filter pattern BP is exposed and transferred using the mask BM to form a land-like blue filter layer B. The blue filter layer B is adjacent to the green filter layer G, and the outer edges thereof are arranged close to each other. Therefore, when the opening 5 of the mask BM has the same shape as the opening 4 of the mask GM, the outer edges of the land-like blue filter layer B and the green filter layer G are fused because the distance between the outer edges is narrow. There is a high probability of wearing. In order to prevent this, the blue filter pattern BP of the mask BM is subjected to processing using optical proximity effect correction (hereinafter referred to as OPC (Optical Proximity Effect Correction) technology).

  That is, as shown in FIG. 2, the opening 5 of the mask BM that forms the blue filter layer B has an opening outer edge 5a adjacent to each of the land-like filter layers G already formed on the substrate P. The opening 5 is shaped so as to enter the distance L. As a result, the distance between the outer edges of the green filter layer G and the blue filter layer B increases, the occurrence of fusion between the outer edges is prevented, and the land-shaped blue filter layer B having a regular shape is formed. The OPC process described above is for preventing the outer edges of the blue filter layer B and the adjacent green filter layer G from being fused. Accordingly, the shape of the opening outer edge 5a of the mask BM is such that the blue filter layer B exposed and transferred onto the substrate P can be exposed and transferred into a regular shape without the outer edges of the green filter layer G being fused. Any other shape may be used and is not particularly limited.

  As the shape of the opening outer edge 5a, for example, as shown in the upper side of FIG. 2, the opening outer edge 5a on the side adjacent to the green filter layer G can have a substantially U-shaped shape. Further, as shown in the lower side of FIG. 2, the opening outer edge 5a on the side adjacent to the green filter layer G can be formed in a substantially V-shaped shape.

  Subsequently, the red filter pattern RP is exposed and transferred using the mask RM on the substrate P on which the land-like green filter layer G and the blue filter layer B are formed as described above, and the land-like red filter layer R is transferred. Is formed between the green filter layer G and the blue filter layer B. Even when the red filter layer R is formed, the land-like red filter layer R is formed so that the outer edge thereof is located close to the outer edges of the green filter layer G and the blue filter layer B, so that the opening 5 of the mask RM is formed. The OPC process is performed so that the opening outer edge 5 a on the side adjacent to each of the land-like filter layers G and B already formed on the substrate P enters the mask opening 5. This prevents the red filter layer R from being fused with the outer edges of the green filter layer G and the blue filter layer B.

  Next, the luminance information filter pattern WP is exposed and transferred using the mask WM onto the substrate P on which the land-like green filter layer G, the blue filter layer B, and the red filter layer R are formed. In a region other than the layer R, the green filter layer G, and the blue filter layer B, for example, a luminance information filter layer W made of a transparent filter material is disposed. In effect, the gap between the filter layers of other colors is filled with the filter layer W. Since the filter layer W here only fills the region other than the land-like red filter layer R, green filter layer G, and blue filter layer B, the opening outer edge of the opening 6 may be subjected to OPC processing. , You do not have to.

  As described above, the blue filter layer B, which is an intermediate process of forming the color filter 100, and the masks BM and RM that form the red filter layer R are subjected to OPC processing so that the opening outer edge 5a of the mask BM enters the inside of the mask opening 5, By forming the blue filter layer B and the red filter layer R using the masks BM and RM, fusion of the outer edges of the filter layers G, B, R, and W is prevented. In other words, when the color filter 100 is formed, the unit color filter is applied to the masks for the colors after the second color and before the final color (W in the embodiment) (B, R in the embodiment). The mask opening has a shape different from the land shape as the normal shape of the pattern. As a result, there is no variation in the thickness of the color filter 100 and the size of the filter layers G, B, R, and W due to the fusion of the filter layers G, B, R, and W, and the color filter has stable optical performance. 100 can be formed. The color formation order is G → B → R → W in the above example, but is not limited to this.

  Next, a method for forming a color filter based on a three-color Bayer arrangement will be described with reference to FIG. FIG. 3 is a conceptual diagram showing a process of forming color filters arranged with a Bayer arrangement inclined at an angle of 45 °. As shown in FIG. 3, the color filter 200 of this arrangement includes a mask having a red filter pattern RP, a mask having a blue filter pattern BP, and a mask having a green filter pattern GP (both shown in FIG. 3). The filter layers R, B, and G are formed on the substrate P in this order by photolithography.

  Specifically, as shown in FIG. 3A, first, the red filter pattern RP is exposed and transferred onto the substrate P to form a land-like red filter layer R. In this case, the openings of the red filter pattern RP are spaced apart from each other by a predetermined distance, like the green filter pattern GP of the mask GM shown in FIG. 1, and the shape of the outer edge of the opening is exposed and transferred to the substrate P. The red filter layer R to be formed is formed in substantially the same shape. Thereby, the land-like red filter layers R are discretely formed on the substrate P.

  Next, as shown in FIG. 3B, the blue filter pattern BP is exposed and transferred onto the substrate P on which the red filter layer R is formed, thereby forming a land-like blue filter layer B. The blue filter layer B is adjacent to the red filter layer R, and the outer edges thereof are arranged close to each other. Therefore, there is a high possibility that fusion occurs between the outer edges of the land-like red filter layer R and the blue filter layer B. In order to prevent this, the optical proximity effect correction is applied to the opening of the blue filter pattern BP like the mask GB and RM shown in FIG. This prevents fusion between the outer edges of the blue filter layer B and the red filter layer R.

  Then, as shown in FIG. 3C, regions other than the land-like red filter layer R and blue filter layer B are filled with a green filter layer G. Since the green filter layer G only fills areas other than the land-like red filter layer R and blue filter layer B, the opening outer edge of the opening may or may not be subjected to OPC processing.

  The color filters 100 and 200 formed as described above are formed on an element substrate on which a photoelectric conversion unit and a charge transfer electrode are formed, or a color filter is formed in advance and bonded in a subsequent process. Thus, a solid-state image sensor is formed.

  According to the pattern mask set for the solid-state imaging device such as the masks GM, BM, RM, WM, etc., among the N (N is an integer of 1 or more) pattern masks, at least the second to the (N-1) th patterning. By forming the pattern mask into a shape in which the edge of the pattern is recessed inward, fusion with another adjacent pattern is prevented.

Next, a specific example of a solid-state imaging device equipped with the above color filter will be described.
FIG. 4 is a cross-sectional view illustrating a configuration of a solid-state imaging device including a color filter.
In the solid-state imaging device 300, a semiconductor substrate 11 such as silicon is doped with impurity ions to form a photoelectric conversion unit 12 such as a photodiode and a transfer channel region (not shown). A plurality of photoelectric conversion units 12 that generate signal charges by receiving incident light are arranged in the plane direction of the imaging surface of the semiconductor substrate 11.

  A gate insulating film 13 is formed on the semiconductor substrate 11 by thermal oxidation, a CVD method (chemical vapor deposition method), or the like. The gate insulating film 13 has, for example, a multilayer structure (ONO film) in which a silicon oxide (SiO) film, a silicon nitride (SiN) film, and a silicon oxide (SiO) film are sequentially stacked.

  On the semiconductor substrate 11, a charge transfer electrode 14 for transferring a signal charge generated in the photoelectric conversion unit 12 is formed via a gate insulating film 13. When the charge transfer electrode 14 is formed, a conductive silicon film (for example, polysilicon or amorphous silicon) is formed on the upper surface of the gate insulating film 13 by the CVD method, and this silicon film is patterned by photolithography. The charge transfer electrode 14 extends along the vertical direction and the horizontal direction of the imaging surface so as to transfer the signal charge generated in the photoelectric conversion unit 12, and in the semiconductor element having the configuration of a solid-state imaging device, the charge transfer unit It has the function of.

Further, an interlayer insulating film 15 made of SiO ₂ and Si ₃ N _{4 is} formed on the gate insulating film 13 so as to cover the charge transfer electrode 14 by the CVD method, and the side and upper surfaces of the charge transfer electrode 14 are formed by photolithography patterning. Then, the interlayer insulating film 15 is selectively left. Further, a light shielding film 16 such as tungsten is formed on the upper surface of the interlayer insulating film 15 of the charge transfer electrode 14. Then, an opening is formed by removing the light shielding film 16 on the photoelectric conversion unit 12 by photolithography patterning.

A transparent insulating layer 17 is formed on the semiconductor substrate 11 and the light shielding film 16. On the upper surface of the insulating layer 17, a color filter array C in which the color filter 100, the planarizing layer 7, and the microlens layer 8 are sequentially stacked is formed. Here, the color filter array C can be manufactured by the procedure of the above-described embodiment, but can also be manufactured separately from the element substrate side on which the photoelectric conversion unit 12 and the charge transfer electrode 14 are formed. In this way, the color filter array C and the element substrate can be manufactured separately and then bonded together, and the manufacturing cost is not affected by the yield of either the color filter array C or the element substrate. Can be reduced. The insulating layer 17 is formed by thermally reflowing a SiO ₂ film containing B (boron) or P (phosphorus), and protects the metal wiring in the peripheral circuit portion or flattens the surface of the laminated surface.

Next, the structure of another solid-state image sensor will be described.
FIG. 5 is a cross-sectional view showing a configuration in which a color filter array is applied to a back-illuminated image sensor.
The back-illuminated imaging device 400 includes a p-type silicon layer (hereinafter referred to as a p layer) 31 and a p ⁺⁺ type silicon layer (hereinafter referred to as a p ⁺⁺ layer) 32 having a higher impurity concentration than the p layer 31. A type semiconductor substrate (hereinafter referred to as a p-substrate) 60 is provided. The back-illuminated imaging element 400 performs imaging by allowing light to enter from the lower side to the upper side in the drawing. In the present specification, of the two surfaces perpendicular to the light incident direction of the p substrate 60, the light incident side surface is referred to as a back surface, and the opposite surface is referred to as a front surface. In addition, when the constituent elements of the back-illuminated image sensor 400 are used as a reference, the direction in which the incident light travels is defined as above the constituent elements, and the direction opposite to the direction in which the incident light travels is defined as the constituent elements. It is defined as below. Further, a direction perpendicular to the back surface and the front surface of the p substrate 60 is defined as a vertical direction, and a direction parallel to the back surface and the front surface of the p substrate 60 is defined as a horizontal direction.

An n-type impurity diffusion layer (hereinafter referred to as n type) for accumulating charges generated in the p substrate 60 in response to incident light is formed on the same surface extending in the horizontal direction near the surface of the p substrate 60 in the p layer 31. A plurality of layers 34) are arranged. The n layer 34 has a two-layer structure of an n layer 34a formed on the surface side of the p substrate 60 and an n ⁻ layer 34b having a lower impurity concentration than the n layer 34a formed under the n layer 34a. However, it is not limited to this. The charges generated in the n layer 34 and the charges generated in the p substrate 60 on the path of light incident on the n layer 34 are accumulated in the n layer 34.

On each n layer 34, a high-concentration p-type impurity diffusion layer (hereinafter referred to as p ⁺ layer) 35 for preventing dark charges generated on the surface of the p substrate 60 from accumulating in each n layer 34 is provided. Is formed. In each p ⁺ layer 35, an n-type impurity diffusion layer (hereinafter referred to as an n ⁺ layer) 36 having a higher concentration than the n layer 34 is formed from the surface of the p substrate 60 toward the inside thereof. The n ⁺ layer 36 functions as an overflow drain for discharging unnecessary charges accumulated in the n layer 34, and the p ⁺ layer 35 also functions as an overflow barrier for this overflow drain. As illustrated, the n ⁺ layer 36 has an exposed surface exposed on the surface of the p substrate 60.

A charge transfer channel 42 composed of an n-type impurity diffusion layer having a higher concentration than the n layer 34 is formed slightly adjacent to the right side of the p ⁺ layer 35 and the n layer 34 in the drawing, and is formed around the charge transfer channel 42. A p layer 41 having a lower concentration than the p ⁺ layer 35 is formed.

In the p layer 41 and the p layer 31 between the p ⁺ layer 35 and the n layer 34 and the charge transfer channel 42, a charge readout region (not shown) for reading out the charges accumulated in the n layer 34 to the charge transfer channel 42. ) Is formed. Charge transfer for controlling the charge transfer operation by supplying a voltage to the charge transfer channel 42 via the gate insulating film 20 made of a silicon oxide film, an ONO film or the like above the charge transfer channel 42 and the charge readout region. An electrode 43 made of polysilicon or the like serving as both an electrode and a charge readout electrode for controlling a charge readout operation by supplying a readout voltage to the charge readout region is formed. An insulating film 44 such as silicon oxide is formed around the electrode 43. The charge transfer channel 42 and the electrode 43 thereabove constitute a CCD.

  An element isolation layer 45 made of a p-type impurity diffusion layer is formed below the p layer 41 between the adjacent n layers 34. The element isolation layer 45 is for preventing the charges to be accumulated in the n layer 34 from leaking to the adjacent n layer 34.

A gate insulating film 20 is formed on the surface of the p substrate 60, and an insulating layer 39 such as silicon oxide is formed on the gate insulating film 20, and an electrode 43 and an insulating film 44 are formed in the insulating layer 39. Is buried. Note that the n ⁺ layer 36 can function as an overflow drain by moving the charge that has moved to the n ⁺ layer 36 to an electrode (not shown) connected to the exposed surface of the n ⁺ layer 36.

A p ⁺⁺ layer 32 is formed on the inner side from the back surface of the p substrate 60 in order to prevent dark charges generated on the back surface of the p substrate 60 from moving to the n layer 34. A terminal is connected to the p ⁺⁺ layer 32, and a predetermined voltage can be applied to the terminal.

Under the p ⁺⁺ layer 32, an insulating layer 33 transparent to incident light such as silicon oxide or silicon nitride is formed. Under the insulating layer 33, incident light such as silicon nitride or diamond structure carbon film is used to prevent reflection of light on the back surface of the p substrate 60 due to a difference in refractive index between the insulating layer 33 and the p substrate 60. A transparent high refractive index transparent layer 46 is formed. The high refractive index transparent layer 46 is preferably a layer having a refractive index exceeding n = 1.46, such as amorphous silicon nitride that can be formed at a low temperature of 400 ° C. or lower, such as plasma CVD or photo-CVD.

  A color filter array C is formed under the high refractive index transparent layer 46. The color filter array C has a configuration in which the color filter 100, the planarization layer 7, and the microlens layer 8 are sequentially laminated from the high refractive index transparent layer 46 side. The color filter array C can be manufactured by the procedure of the above embodiment.

  In the back-illuminated imaging device 400 configured in this way, light incident on one microlens of the color filter array C is incident on the color filter 100 above the microlens, and the light transmitted therethrough is the color filter. It is incident on the n layer 34 corresponding to 100 colors. At this time, charges are also generated in the portion of the p substrate 60 that serves as a path for incident light. However, the charges move to the n layer 34 via the potential slope formed in the photoelectric conversion region and are accumulated there. The The charges generated here by entering the n-layer 34 are also accumulated here. The charge accumulated in the n layer 34 is read and transferred to the charge transfer channel 42, converted into a signal by an output amplifier, and output to the outside.

As described above, the above-described color filter of the solid-state imaging device is incorporated in the solid-state imaging device as shown in FIGS. 4 and 5 as an example. It is possible to obtain a solid-state imaging device having excellent device characteristics that does not deteriorate the ratio.
The color filter and the solid-state imaging device according to the present invention are not limited to the above-described embodiments, and can be modified or improved as appropriate. For example, in the above description, the color filter has been described as being applied to a CCD solid-state image sensor, but it can also be applied to a CMOS solid-state image sensor and has the same effect.

  As described above, the color filter forming method, the solid-state image sensor, and the pattern mask set for the solid-state image sensor of the present invention can be used for various photographing apparatuses such as a digital camera and a video camera. In particular, it is possible to prevent a decrease in device characteristics of the solid-state imaging device such as a decrease in sensitivity, color mixing, and deterioration in sensitivity ratio.

It is a conceptual diagram which shows the process of patterning and forming the chromaticity filter layer for color information detection, and the brightness | luminance filter layer for brightness | luminance information measurement on a board | substrate using the mask of a unit color filter pattern which differs for every color. It is a top view which shows the shape of the opening outer edge of the mask in FIG. It is a conceptual diagram which shows the formation process of a color filter of 3 colors. It is sectional drawing which shows the structure which applied the color filter to the solid-state image sensor. It is sectional drawing which shows the structure which applied the color filter to the backside illumination type solid-state image sensor. It is a top view which shows the arrangement | sequence of each filter layer of the color filter which inclined 45 degrees of Bayer arrangement. It is a conceptual diagram which shows the conventional formation process of the color filter shown in FIG. It is a top view which shows the arrangement | sequence of each filter layer of the color filter with which the chromaticity filter for color information detection, and the luminance filter for luminance information measurement were arranged. It is a conceptual diagram which shows the conventional formation process of the color filter shown in FIG.

Explanation of symbols

4 opening (mask opening)
5 opening (mask opening)
6 opening (mask opening)
5a Opening edge 12 Photoelectric conversion part (light receiving part, photodiode)
14 Charge transfer electrode (output part)
DESCRIPTION OF SYMBOLS 100 Color filter 200 Color filter 300 Solid-state image sensor 400 Back-illuminated image sensor R Red filter layer (chromaticity filter)
G Green filter layer (chromaticity filter)
B Blue filter layer (chromaticity filter)
W Luminance information filter layer (luminance filter)
RM mask GM mask BM mask WM mask RP Red filter pattern (unit color filter pattern)
GP Green filter pattern (unit color filter pattern)
BP Blue filter pattern (unit color filter pattern)
WP Filter pattern for luminance information (unit color filter pattern)
P substrate

Claims (7)

A color filter in which land-like filter layers are mixedly arranged in different patterns for each color is used, and the land-like filter layers for each color are patterned on the substrate in color order using a different unit color filter pattern mask for each color. A method for forming a color filter of a solid-state imaging device to be formed,
After the land-shaped filter layer of the first color is patterned on the substrate using a unit color filter pattern mask corresponding to the color of the first color,
When the land-like filter layer for the colors after the second color and before the final color is formed by patterning between the filter layers of the first color, the colors after the second color and before the final color A method of forming a color filter for a solid-state imaging device, wherein each of the openings of the mask is formed in a shape different from the land shape of each filter layer of the unit color filter pattern for the color. A color filter forming method for a solid-state imaging device according to claim 1,
Each opening shape of the mask with respect to colors after the second color and before the final color has an opening outer edge on the side adjacent to each land-like filter layer already formed on the substrate inside the opening. A method for forming a color filter of a solid-state imaging device having an intrusive shape. A method for forming a color filter of a solid-state imaging device according to claim 1 or 2,
The color filter includes a chromaticity filter for detecting color information and a luminance filter for measuring luminance information respectively arranged on the light incident side of the plurality of photodiodes, and arranged in a checkered pattern among the plurality of photodiodes. The chromaticity filter is arranged for the photodiodes arranged, and the luminance filter is arranged for the remaining checkered photodiodes where the chromaticity filters are not arranged,
A method for forming a color filter of a solid-state imaging device, wherein a filter layer for the chromaticity filter is formed in color sequential order, and then a filter layer for the luminance filter is formed. A method for forming a color filter of a solid-state imaging device according to claim 1 or 2,
In the color filter, green, blue, and red filter layers are arranged on the light incident sides of a plurality of photodiodes, respectively, and a filter layer for green is formed after forming a filter layer for blue and red A method for forming a color filter of an element. A plurality of light receiving parts for detecting light; and
A color filter disposed on an incident light side of the light receiving unit;
An output unit for outputting a light reception signal from the light receiving unit;
A solid-state imaging device comprising:
The solid-state image sensor in which the said color filter was formed using the color filter formation method of any one of Claims 1-4. A pattern mask set for a solid-state imaging device for forming a color filter having a different pattern for each color in color sequence,
Solid imaging in which at least a part of the pattern mask has a shape corresponding to the pattern at least a part of the part adjacent to the pattern of another color, and the edge of the pattern is recessed inward. Pattern mask set for elements. It is a pattern mask set for solid-state image sensors according to claim 6,
The at least part of the pattern mask is an N-th pattern mask for patterning from at least the second to N-1 among N (N is an integer of 1 or more) pattern masks;
The pattern mask set for a solid-state imaging device, wherein the pattern of the other color is the pattern that has already been patterned.

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