JP2001144277A - Method for producing color filter and solid state image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a color filter inexpensively by facilitating production of a white filter, and a solid state image sensor equipped with that color filter. SOLUTION: At the time of producing a color filter 15 having at least an yellow filter YE and a white filter W and comprising a resist containing a dye, the white filter W is formed by making a resist 12 containing the same dye as the yellow filter YE thinner than the yellow filter YE. The solid state image sensor is equipped with a color filter 15 having at least an yellow filter YE and a white filter W and comprising a resist containing a dye wherein the white filter W is formed by making the resist 12 containing the same dye as the yellow filter YE thinner than the yellow filter YE.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method of manufacturing a color filter and a solid-state imaging device having the color filter.

[0002]

2. Description of the Related Art In a solid-state color image pickup device, an on-chip color filter is formed on a sensor section, and the on-chip color filter is configured by repeatedly arranging a plurality of color filters in a predetermined arrangement. Thus, a signal of a desired color can be obtained.

There are many types of color coding (color arrangement) of this color filter. Of these, a white color filter W and a yellow color filter Y are arranged in a complementary color system.
In some cases, four color filters of E, cyan filter CY, and green filter G are formed.

Conventionally, color filters of solid-state imaging devices have generally been formed by a dyeing method. In the case of this dyeing method, a chromosome, such as casein or gelatin, is colored with a dye having a color corresponding to the color of the filter to form a color filter.

The above four colors (W, YE, CY,
In the case of forming the color filter of G), the white filter W is formed by coloring the chromosome with a yellow filter YE dye. For this reason, no dye or dye layer dedicated to the white filter W was required.

[0006]

In recent years, with the miniaturization of unit cells of a solid-state imaging device, it has become difficult to form a fine color filter with high accuracy by the above-described staining method. Therefore, dye-containing resists having excellent processability have been adopted.

However, when the white filter W is to be formed from the dye-containing resist, it is necessary to newly develop and use a resist containing the dye for the white filter W, and the manufacturing apparatus requires the white filter W to contain the dye. It is necessary to equip a new production line for resist. Therefore, there arises a problem that capital investment and manufacturing cost increase.

In order to solve the above-mentioned problems, in the present invention, a white filter can be easily manufactured, so that a method of manufacturing a color filter which can be manufactured at a low cost and this color filter can be manufactured. And a solid-state imaging device having the same.

[0009]

According to the method for producing a color filter of the present invention, in producing a color filter comprising at least a yellow filter and a white filter and comprising a dye-containing resist, the same dye-containing resist as the yellow filter is used. This is to form a white filter with a thickness smaller than the thickness of the yellow filter.

The solid-state image pickup device of the present invention has at least a yellow filter and a white filter, and is made of a dye-containing resist. The same dye-containing resist as the yellow filter is thinner than the yellow filter to form a white filter. It is provided with a color filter.

According to the above-described method of the present invention, the same dye-containing resist as that of the yellow filter is formed thinner than the thickness of the yellow filter to form a white filter. Do not need. Further, the step of forming the white filter can be incorporated into the step of forming the yellow filter.

According to the structure of the solid-state image pickup device of the present invention, the same dye-containing resist as that of the yellow filter is thinner than the thickness of the yellow filter, and the color filter having the white filter is provided. A solid-state imaging device having a white filter that can be manufactured without increasing cost can be configured.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a method for producing a color filter comprising at least a yellow filter and a white filter and comprising a dye-containing resist. This is a method of manufacturing a color filter that forms a white filter by thinning.

Further, according to the present invention, in the above-mentioned method for producing a color filter, after forming a dye-containing resist layer having a thickness of a yellow filter, a first exposure step of exposing the entire thickness of the dye-containing resist, A second exposure step of exposing a part of the thickness of the resist and a second exposure step are performed, and then collective development is performed to form a yellow filter and a white filter.

The present invention comprises a dye-containing resist having at least a yellow filter and a white filter,
The solid-state imaging device includes a color filter in which the same dye-containing resist as the yellow filter is thinner than the thickness of the yellow filter to form a white filter.

As an embodiment of the present invention, FIG. 1 shows an embodiment of color coding (color arrangement) of a color filter to which the present invention is applied. Four color filters of a white filter W, a yellow filter YE, a cyan filter CY, and a green filter G are used, and the upper half 4 pixels and the lower half 4 pixels are arranged such that left and right colors are interchanged. The color filters are arranged on the pixels arranged in a matrix, with the two horizontal pixels and the four vertical pixels as the repeating unit of the color arrangement of the color filters.

FIG. 2 shows the spectral characteristics of the four color filters W, YE, CY, and G used in the color coding shown in FIG. Among the four colors shown in FIG. 2, the spectral characteristics of the white filter W are such that the transmittance on the long wavelength side is almost 100%, the occurrence of moire due to the luminance difference between lines is suppressed, and the color reproducibility is improved. For this purpose, the transmittance on the short wavelength side is reduced.

Further, it is ideal that the curve on the short wavelength side of the spectral characteristic of the white filter W matches the curve of the spectral characteristic of the cyan filter CY.

The spectral characteristics of the white filter W can be obtained by increasing the transmittance from the spectral characteristics of the yellow filter YE. Therefore, it is understood that the spectral characteristics of the white W filter can be obtained by reducing the thickness of the yellow YE filter so as to increase the transmittance.

Here, the dye-containing resist is formed by mixing a resin such as a novolak resin, a photoresist made of a photosensitive agent and a curing agent, and a dye of a predetermined color.

The white filter W can be formed at the same time as the yellow filter YE using a yellow dye-containing resist for the yellow filter YE using a known photolithography technique.

The spectral characteristics of the white filter W shown in FIG. 2 can be obtained at about 20% absorbance of the yellow filter YE. That is, by setting the film thickness to about 20% of the yellow filter YE, the desired spectral characteristics of the white filter W shown in FIG. 2 can be obtained.

The film thickness at which the yellow filter YE has the spectral characteristics shown in FIG. 2 is 1.5 μm. Therefore, the white filter W has the desired spectral characteristics shown in FIG. 2 by setting the film thickness of 20% to 0.3 μm.

FIG. 3 shows the relationship between the exposure amount and the residual film ratio after development in the yellow dye-containing resist. When the exposure amount is 3000 ms (millisecond), the residual film ratio becomes 0%. At an exposure amount of 1000 ms, the residual film ratio becomes 20%, the film thickness becomes the optimum as the white filter W, and the optimum spectral characteristics shown in FIG. 2 are obtained.

Next, a method of forming a color filter including a white filter W using the result will be described with reference to FIGS.
This will be described with reference to FIG. FIGS. 4 and 5 do not show specific cross sections in the color coding of FIG. 1, but are schematic diagrams in which four color filters W, YE, CY, and G are included.

First, as shown in FIG. 4A, a yellow dye-containing resist 12 is applied to a thickness of 1.5 μm on an underlayer 11 having a flat surface. Below the underlayer 11, a sensor unit (not shown), a transfer electrode, a light-shielding film, a CCD register, and the like in the case of a CCD solid-state imaging device are formed.

Next, as shown in FIG. 4B, a portion other than the portion where the yellow filter YE and the white filter W are to be formed is covered with a first mask 13 so that a yellow dye-containing resist 1 is formed.
A first exposure of 3000 ms is performed on the sample No. 2 using an i-line stepper.

Next, as shown in FIG. 4C, the i-line stepper covers the yellow dye-containing resist 12 with the i-line stepper by covering it with a second mask 14 so that only the portion to be the white filter W is exposed. A second exposure is performed.

Next, as shown in FIG. 4D, the exposed portions are removed by batch development and heat curing to form a yellow filter YE and a white filter W, each made of a yellow dye-containing resist 12. .

Subsequently, the same processing as that shown in FIGS. 4A, 4B, and 4D is performed on the cyan dye-containing resist, and the same processing is further performed on the green dye-containing resist, thereby forming the cyan filter CY and the green filter G. Then, for example, a color filter 15 as shown in FIG. 5 can be formed. Thereafter, although not shown, if necessary, the surface is flattened by covering with an insulating film, and an on-chip lens or the like is formed to form a solid-state imaging device.

In this manner, four color filters of the white filter W, yellow filter YE, cyan filter CY, and green filter G having the pattern shown in FIG. 1 can be formed.

In the above-described embodiment, in the step of exposing the portion where the white filter W is formed, the second mask 14 different from the first mask 13 for the yellow filter YE is used.
And the exposure step is performed in two steps.
That is, after forming a layer of the yellow dye-containing resist 12 having a thickness of the yellow filter YE, a first exposure step of exposing the entire thickness of the yellow dye-containing resist 12 using the first mask 13, And a second exposure step of exposing a part of the thickness of the yellow dye-containing resist 12 using the mask 14 described above.

On the other hand, it is also possible to put a pattern for exposing the portion of the white filter W on the mask for the yellow filter YE and perform the exposure once. In particular,
Work is performed on the mask for the yellow filter YE to reduce the transmittance of the pattern in the portion of the white filter W. Thus, the number of steps can be reduced, and the productivity can be further improved.

The thickness of the white filter W is preferably 65% or less of the thickness of the yellow filter YE in order to realize the function of the white filter W. More preferably, it is 50% or less. Ideally, the thickness is 20% as described above.

According to the above-described embodiment, the white filter W is formed using the yellow dye-containing resist 12 in the same manner as the yellow filter YE, so that a special dye-containing resist is required for forming the white filter W. do not do. Therefore, it is possible to reduce the manufacturing cost, and it is not necessary to newly provide a facility for forming the white filter W, thereby suppressing an increase in facility investment.

Further, since the white filter forming step can be incorporated into the yellow filter forming step and can be dealt with only by devising the exposure step or the like, the step for forming the white filter W is specially performed. It is not necessary to form the color filter 15 having the white filter W with high productivity.

In the above-described embodiment, a case where a positive resist is used as the dye-containing resist 12 for the yellow filter YE has been described. However, the present invention can be similarly applied to a case where a negative resist is used.

Similarly, when a negative resist is used, a first exposure step for exposing the entire thickness of the yellow dye-containing resist and a second exposure step for exposing a part of the thickness of the yellow dye-containing resist are similarly performed. By performing the exposure process twice, the yellow filter YE and the white filter W having different film thicknesses can be formed. Even when this negative resist is used, batch development and use of a mask having a different transmittance can be similarly performed.

The color filter of the present invention is not limited to a solid-state image pickup device using a color filter, but may be a CCD solid-state image pickup device or other solid-state image pickup device such as an MO.
The same applies to the S-type solid-state imaging device.

Although the present invention can be used for a color filter of a display device such as a liquid crystal display, the present invention is particularly configured to obtain a predetermined color signal by using a white filter for the color filter. Therefore, the present invention exerts a further effect when used in a configuration in which a predetermined signal output is obtained by calculating an optical signal obtained by receiving and detecting light separated by an image sensor, for example, a color filter.

The present invention is not limited to the above-described embodiment, and may take various other configurations without departing from the gist of the present invention.

[0042]

According to the present invention described above, since a special dye-containing resist is not required for forming a white filter, the manufacturing cost can be reduced. Moreover, since it is not necessary to newly provide a facility for forming a white filter, it is possible to suppress an increase in facility investment.

Further, according to the present invention, since a step for forming a white filter is not required, a color filter including a white filter and a solid-state imaging device having the color filter can be manufactured with high productivity.

[Brief description of the drawings]

FIG. 1 is a diagram showing one mode of color coding (color arrangement) of a color filter to which the present invention is applied.

FIG. 2 is a diagram showing spectral characteristics of four color filters used for color coding shown in FIG. 1;

FIG. 3 is a graph showing a relationship between an exposure amount and a residual film ratio after development in a dye-containing resist for a yellow filter.

4A to 4D are manufacturing process diagrams illustrating a method of forming a color filter including a white filter according to an embodiment of the present invention.

FIG. 5 is a manufacturing process diagram showing a method of forming a color filter including a white filter according to one embodiment of the present invention.

[Explanation of symbols]

11 underlayer, 12 yellow dye-containing resist, 13
1st mask, 14 second mask, 15 color filter, W white filter, YE yellow filter, CY cyan filter, G green filter

Claims (3)

[Claims] 1. A method of manufacturing a color filter comprising at least a yellow filter and a white filter and comprising a dye-containing resist, wherein the same dye-containing resist as the yellow filter is thinner than the thickness of the yellow filter. A method for manufacturing a color filter, comprising forming a white filter. 2. After forming a dye-containing resist layer having a thickness of the yellow filter, a first exposure step of exposing the entire thickness of the dye-containing resist, and a part of the thickness of the dye-containing resist are performed. 2. The color filter according to claim 1, wherein a second exposure step of exposing is performed, and two exposure steps are performed, and then collective development is performed to form the yellow filter and the white filter. Method. 3. A color filter having at least a yellow filter and a white filter, comprising a dye-containing resist, wherein the same dye-containing resist as the yellow filter is thinner than the thickness of the yellow filter to form the white filter. A solid-state imaging device comprising: