JPH0996712A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain color filters aligned with high accuracy by making it possible to detect alignment marks with high accuracy even in colored resist layers of any colors. SOLUTION: Transparent layers 3 having translucency to light (alignment light) 5 of a prescribed wavelength are formed in the positions right above the alignment marks 2 formed on a substrate 1. A colored resist liquid is applied on the substrate 1 so as to cover the transparent layers 3 in such a manner the thickness on the transparent layers 3 is made smaller than the thickness at other points, by which the colored resist layers 4 consisting of the resist liquid are formed. In succession, the substrate 1 is irradiated with the alignment light 5 to detect the alignment marks 2. The mask is aligned to the substrate 1 in accordance with the result of the detection. The colored resist layers 4 are exposed by using a mask and are then developed, by which the colored resist layers 4 are formed to the patterns of prescribed filters 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter manufacturing method suitable for manufacturing a color filter such as a CCD solid-state image pickup device or an LCD display device.

[0002]

2. Description of the Related Art A conventional color filter manufacturing method is
Colored resist layer (hereinafter referred to as colored resist layer)
There is a so-called color resist method in which the pattern formed in 1) is used as it is as a color filter.

In the color resist method, for example, when a flattening layer 51 is formed on a substrate 50 as shown in FIG. 3, a colored resist layer (hereinafter referred to as a colored resist layer) is first formed on the flattening layer 51. ) 52 is formed. Next, the alignment light 53 of the exposure apparatus is irradiated toward the substrate 50 to detect the alignment mark 54 formed on the substrate 50, and based on this result, the colored resist layer 52 is detected.
Align a mask (not shown) on top. Then, the colored resist layer 52 is exposed by using the aligned mask, and then developed to form the colored resist layer 52 in a predetermined pattern, and a color filter (not shown) formed of the pattern.
To form In this method, the above steps are repeated for each color constituting the color filter, for example, for each of red, green, and blue, to manufacture a color filter composed of these three color filters.

[0004]

However, in the method of manufacturing a color filter using the color resist method, unlike the ordinary photolithography process, the resist layer itself is colored. The following problems occur when aligning the substrate and the mask. For example, when manufacturing a color filter composed of red, green, and blue filters, unless the alignment light is light that is sufficiently transmissive to the red, green, and blue colored resist layers, the colored resist layer Unable to detect the alignment mark below. In order to meet such requirements, it is possible to use, for example, white light as the alignment light, but when this light contains a blue component, there arises a problem that most of the colored resist layers are exposed.

When wide band light such as white light is used, it is difficult to accurately detect the position of the alignment mark due to the chromatic aberration of the exposure apparatus optical system. This becomes a serious problem especially when manufacturing a color filter of an element such as a solid-state image sensor that requires a fine pattern.

For the above reasons, usually, monochromatic light, particularly red light, is often used as the alignment light of the exposure apparatus. However, the red light is the light absorbed by the green resist and the blue resist, and as shown in FIG. 3, conventionally, the colored resist layer 52 is formed to be thick just above the alignment mark 54 as in other places. Therefore, when the red light is used as the alignment light, the alignment light cannot be transmitted through the green resist and the blue resist, and the alignment mark cannot be detected.

The present invention has been made to solve the above problems, and it is possible to detect an alignment mark with high accuracy in a colored resist layer of any color, which allows a color to be aligned with high accuracy. An object of the present invention is to provide a color filter manufacturing method capable of manufacturing a filter.

[0008]

In the method of manufacturing a color filter according to the present invention, in order to solve the above-mentioned problems, first, a light having a predetermined wavelength is transmitted directly above an alignment mark formed on a substrate. Forming a transparent transparent layer, and then applying a colored resist solution onto the substrate so as to cover the transparent layer, so that the thickness of the transparent layer becomes thinner than the thickness of other parts. To form a colored resist layer. Subsequently, the substrate is irradiated with light of a predetermined wavelength to detect the alignment mark, and the mask is aligned with the substrate based on the detection result. Then, the colored resist layer is exposed using a mask and then developed to form the colored resist layer in a predetermined pattern.

In the method of the present invention, after forming the transparent layer, the colored resist layer is formed so that the thickness on the transparent layer is smaller than the thickness of other portions. When the light having a predetermined wavelength is irradiated toward the substrate, the light transmitted through the colored resist layer on the transparent layer even if it is colored with a color that absorbs. Further, since the transparent layer is made of a layer having a light-transmitting property with respect to the light having the predetermined wavelength, the light transmitted through the colored resist layer further passes through the transparent layer and reaches the alignment mark.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a method for manufacturing a color filter according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of the present invention in process order. Figure 1
As shown in (a), first, a transparent layer 3 having a light-transmitting property with respect to light having a predetermined wavelength, that is, alignment light of an exposure apparatus is formed immediately above the alignment mark 2 formed on the substrate 1. To do. Here, the alignment mark 2
A transparent layer 3 is formed immediately above the substrate so as to cover the alignment mark 2.

The transparent layer 3 can be formed of various materials such as transparent resin as long as it has a property of transmitting alignment light, and can be formed by various methods depending on the material used. For example, when the alignment light is red light, a colorless resist, a yellow resist, a red resist, or the like can be used as the material of the transparent layer 3, and the transparent layer 3 can be formed by patterning or the like. Also transparent layer 3
Has a thickness that does not adversely affect the application of the colored resist solution in the next step.

After the transparent layer 3 is formed, a colored resist solution is applied to the substrate 1 so as to cover the transparent layer 3 by, for example, a spin coating method, and the thickness on the transparent layer 3 is different from that of other portions. The colored resist layer 4 made of a resist solution is formed so as to be thinner than that. Here, for example, the colored resist layer 4 is formed so that the thickness of other portions is about 1 to 2 μm and the thickness on the transparent layer 3 is about half of the film thickness of other portions.

Usually, the resist solution has a viscosity that allows it to flow from the upper side to the lower side of the transparent layer 3 by its own weight when the resist solution is applied. Therefore, when coating is performed using a resist solution, the thickness of the resist layer formed is almost constant on the flat surface, and is thicker in the concave portion than in the flat surface, and conversely in the convex portion. There is a phenomenon that it becomes thinner than on a flat surface. This phenomenon is naturally observed when the spin coating method is used. Therefore, by applying a colored resist solution onto the substrate 1 on which the transparent layer 3 protruding from the upper surface of the substrate 1 is applied, the colored resist layer 4 made of the resist solution is formed to have a thickness on the transparent layer 3. It can be formed to be thinner than the thickness of other portions.

After the colored resist layer 4 is formed in this way, the alignment light 5 is irradiated toward the substrate 1 to detect the alignment mark 2, and the colored resist layer 4 is formed into a predetermined pattern based on the detection result. The mask (not shown) is aligned with the substrate 1. Next, the colored resist layer 4 is exposed using the above mask, and then developed to form the colored resist layer 4 in a predetermined pattern as shown in FIG. 1B, and a filter having the pattern of the colored resist layer 4 is formed. Get 6.

When manufacturing a color filter composed of, for example, three colors of red, green, and blue, after the red filter 6 is formed by the above-mentioned steps, the steps after the formation of the transparent layer 3 are performed. Repeated for each of the two colors, the color filter 7 including the filters 6 of the above three colors
To manufacture.

In the method of the above embodiment, the transparent resist layer 3 is formed and then the resist solution is applied so that the colored resist layer 4 becomes thinner on the transparent resist layer 3 than at other places. Since the alignment light 5 can be formed, the alignment light 5 can be transmitted through the colored resist layer 4 on the transparent layer 3 even if the alignment light 5 is red light absorbed by the green resist or the blue resist. Further, since the transparent layer 3 is made of a layer having a property of transmitting the alignment light 5, the alignment light transmitted through the colored resist layer 4 is further transmitted through the transparent layer 3 and the alignment mark 2 is formed.
Can be reached.

Therefore, even if the white light is not used as the alignment light 5, the position of the alignment mark 2 can be accurately detected in the colored resist layer 4 of any color, and the mask can be accurately placed on the substrate 1. Therefore, the color filter 7 aligned with high precision can be manufactured.

In the above embodiment, after the transparent layer 3 is formed, each of the three colors forming the color filter 7 is
The case where the series of steps of forming the colored resist layer 4, aligning the substrate 1 and the mask, exposing, and developing is repeated has been described. For example, the transparent layer is formed at the same time when the first filter is formed, and then the remaining It is also possible to manufacture a color filter by repeating the above series of steps for two colors.

For example, when the red filter is formed first, the red filter and the transparent layer are simultaneously patterned from the red resist layer, and then the green and blue filters are formed.
In this case, if the red light that passes through the red resist layer is used as the alignment light, the substrate and the mask can be aligned without forming the transparent layer when forming the red filter. It is possible to accurately form the filter and the transparent layer at a predetermined position. Further, since the transparent layer can be formed simultaneously with the formation of the first filter, the filter can be manufactured without increasing the number of steps.

In the above embodiment, the colored resist layer 4 is used.
Although the spin coating method was used as the forming method of the above, other methods can be used as a matter of course. Furthermore, in the above-described embodiment, the thickness of the other portions is about 1 to 2 μm, and the transparent layer 3
Although the colored resist layer 4 was formed such that the upper thickness was about half the film thickness at other locations, the colored resist layer in the present invention has a thickness on the transparent layer smaller than that at other locations. The size is not limited to the above size. Further, the colored resist layer may be formed on the transparent layer in a state in which the colored resist layer has no thickness, and if it is formed in this way, the position of the alignment mark can be detected more accurately.

In the above embodiment, the case where the transparent layer 3 is formed directly on the alignment mark 2 has been described. However, if the transparent layer is formed immediately above the alignment mark, for example, as shown in FIG. Another layer such as the flattening layer 8 may be interposed between the mark 2 and the transparent layer 3. However, it is necessary that the other layers are layers having a light-transmitting property with respect to light (eg, alignment light) transmitted through the transparent layer.

In the case of manufacturing a color filter in which a flattening layer 8 having translucency for the alignment light 5 is interposed between the alignment mark 2 and the transparent layer 3,
As shown in FIG. 2A, a flattening layer 8 is formed on the substrate 1 so as to cover the alignment marks 2, and then the flattening layer 8 is formed.
The transparent layer 3 is formed immediately above the alignment mark 2 in FIG. Next, the colored resist layer 4 is formed on the substrate 1 with the planarizing layer 8 interposed therebetween so that the thickness on the transparent layer 3 is smaller than the thickness of other portions. Then, similarly to the above-described embodiment, the alignment mark 2 is detected by irradiation of the alignment light 5, the mask and the substrate 1 are aligned, and then exposed and developed to form the colored resist layer 4 as shown in FIG. 2B. A filter 6 having the pattern of is obtained.

Even when the flattening layer 8 is interposed between the alignment mark 2 and the transparent layer 3, the flattening layer 8 is transparent to the alignment light 5, so that the colored resist is used. The alignment light transmitted through the layer 4 and the transmission layer 3 can be transmitted through the flattening layer 8 and reach the alignment mark 2. Therefore, also in this case, the same effect as that of the above-described embodiment can be obtained, and the color filter 9 aligned with high accuracy can be manufactured.

[0024]

As described above, according to the method of manufacturing a color filter of the present invention, after forming a transparent layer having a property of transmitting light of a predetermined wavelength, the thickness on the transparent layer may be different. Since the colored resist layer is formed so that it is thinner than the thickness of the area, even if the colored resist layer is colored in a color that absorbs light of a predetermined wavelength, it is possible to accurately detect the position of the alignment mark. It can be carried out. Therefore, in any of the colored resist layers of any color, the mask can be aligned with the substrate with high precision, so that a color filter that is aligned with high precision can be manufactured. Defects can be reduced.

[Brief description of drawings]

1A and 1B are side cross-sectional views of a main part for explaining an embodiment of a method for manufacturing a color filter according to the present invention in the order of steps.

2A and 2B are side cross-sectional views of a main part for explaining another embodiment of the method for manufacturing a color filter according to the present invention in the order of steps.

FIG. 3 is a diagram illustrating an example of a conventional color filter manufacturing method.

[Explanation of symbols]

 1 substrate 2 alignment mark 3 transparent layer 4 colored resist layer 5 alignment light 7, 9 color filter

Claims (1)

[Claims] 1. A step of forming a transparent layer having a light-transmitting property with respect to light having a predetermined wavelength at a position directly above an alignment mark formed on a substrate, and coloring the substrate so as to cover the transparent layer. A step of applying a colored resist layer formed of the resist solution such that the thickness of the transparent layer is thinner than the thickness of other portions, and the predetermined wavelength of the predetermined wavelength is applied to the substrate. Detecting the alignment mark by irradiating with light, aligning a mask with the substrate based on the detection result, and exposing the colored resist layer using the mask, and then developing the colored resist. And a step of forming a layer in a predetermined pattern.