JPH1187676A - Manufacture of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily remove a resist layer by a lift-off method of the step of manufacturing a color filter. SOLUTION: This method for manufacturing a color filter comprises the steps of forming a first resist layer 12 having openings 13 which corresponds to a filter pattern on a base plate 11, forming a pigment layer 14 on the layer 12, forming a second resist layer 15 for embedding the openings 13 to planarize a surface on the layer 14, etching the layer 15 flat to have the layer 12 exposed, having the layers 12, 15 dissolve in a solvent to remove them together with the layer 14 sandwiched therebetween, and forming a filter layer 16 on a surface of the plate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for forming a color filter for optical color separation.

[0002]

2. Description of the Related Art When color imaging is performed using a solid-state imaging device having a semiconductor structure, a color filter corresponding to three primary colors of light or its complementary color is mounted on a light receiving surface of the solid-state imaging device. A color filter of a solid-state imaging device used in a single-panel imaging device is configured such that each color component is arranged in a stripe or mosaic shape, and each light-receiving pixel of the solid-state imaging device is associated with a specific color component.

FIG. 2 is a plan view showing an example of a mosaic type color filter. The color filters are arranged in a matrix such that a plurality of segments C respectively associated with specific color components correspond to the arrangement of the light receiving pixels of the solid-state imaging device. For example, segments C1 and C2 associated with cyan (Cy) and yellow (Ye) are alternately arranged in odd rows, and segments C3 and C4 associated with white (W) and green (G) are arranged in even rows. They are arranged alternately. The combination of the colors of the segments C1 to C4 is selected from the three primary colors of light and their complementary colors. Thus, information charges representing the color components of the respective segments C1 to C4 are accumulated in each light receiving pixel of the solid-state imaging device.

In such a color filter, a filter plate in which the segments C1 to C4 are arranged corresponding to the arrangement of the light receiving pixels is mounted on the solid-state imaging device, or each segment C1 is mounted on the substrate of the solid-state imaging device. This is realized by a so-called on-chip filter that forms a filter layer constituting C4 to C4. In general, on-chip filters that are advantageous for miniaturization and that can be reduced in cost tend to be used.

FIGS. 3A to 3D are cross-sectional views for explaining steps of a method of manufacturing a color filter, each showing a light receiving region where a plurality of light receiving pixels of a solid-state image sensor are formed. (A) First Step A resist is applied to the surface of the semiconductor substrate 1 to form a resist layer 2 having a constant thickness. It is assumed that a plurality of light receiving pixels and a plurality of shift registers for transferring information charges accumulated in the light receiving pixels are formed in advance on the semiconductor substrate 1.

(B) Second Step After exposing the resist layer 2 with an exposure mask 3 having a predetermined opening window 4, the resist layer 2 is developed to form an opening 5 for exposing the surface of the semiconductor substrate 1. Form. The opening window 4 of the exposure mask 3 is provided so as to coincide with a light receiving pixel to be made to correspond to a specific color component among a plurality of light receiving pixels formed on the surface of the semiconductor substrate 1. Thereby, a desired light receiving pixel is exposed in the opening 5 of the resist layer 2.

(C) Third Step The surface of the resist layer 2 in which the opening 5 is formed and the opening 5
A pigment layer 6 of a desired color is formed so as to cover the surface of the semiconductor substrate 1 (light receiving pixel) exposed on the bottom surface of the substrate. This pigment layer 6
Transmits only light of a specific wavelength according to the material and film thickness. For example, an organic material is formed to have a substantially uniform film thickness by vapor deposition.

(D) Fourth Step The resist layer 2 is melted with a solvent, and the pigment layer 6 on the resist layer 2 is removed from the semiconductor substrate 1 together with the resist layer 2 by a so-called lift-off method. 5 only the pigment layer 6 remains. Thus, a filter layer 7 corresponding to a specific color component is formed on the surface of the semiconductor substrate 1 corresponding to a desired light receiving pixel.

In the first to fourth steps, only one kind of color component is formed out of the plurality of segments C1 to C4 of the color filter. Therefore, when a color filter having four types of segments C1 to C4 as shown in FIG. 3 is formed, the first type of segments C1, C2, and C3 excluding white (W) is formed in order. The fourth to fourth steps are repeated.

[0010]

In the lift-off method of the fourth step, the resist layer 2 covered with the pigment layer 6 is melted by a solvent. At this time, the resist layer 2 may be protected by the pigment layer 6, and the solvent may not sufficiently penetrate into the resist layer 2 to be removed.
Alternatively, an unnecessary portion of the pigment layer 6 may be left on the semiconductor substrate 1. Resist layer 2 left on semiconductor substrate 1
And a part of the pigment layer 6 becomes an obstacle when repeatedly forming the plurality of filter layers 7 and, when peeled off and adhered to the light receiving pixels in a later step, causes problems such as scattering of incident light and a decrease in light receiving sensitivity. Invite. Alternatively, if processing is continued until the resist layer 2 can be completely removed, the pigment layer 6 formed of an organic material is damaged by the solvent, and the filter layer 7 cannot obtain desired optical characteristics. This causes a problem that the color reproducibility of the solid-state imaging device is reduced.

Accordingly, an object of the present invention is to make it possible to reliably remove an unnecessary resist layer or pigment layer on a semiconductor substrate in a short time by a lift-off method used in one step when forming a color filter. I do.

[0012]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the feature of the present invention is that a plurality of light receiving elements or display elements are arranged on a surface of a substrate. In a method of manufacturing a color filter for forming a filter layer having a predetermined pattern shape, a first resist layer is formed on the surface of the substrate, and the resist layer is selectively exposed to light to partially expose the surface of the substrate. A first step of forming a pigment layer corresponding to a specific color component over the surface of the substrate exposed to the opening after forming the opening to be exposed, and at least the opening on the pigment layer A second step of forming a second resist layer for filling the surface and flattening the surface, and a third step of etching the second resist layer flat to expose at least a part of the first resist layer. The first resist layer and a part of the second resist layer left in the opening are melted, and together with a part of the pigment layer sandwiched between the first resist layer and the second resist layer. And a fourth step of removing.

According to the present invention, since the first resist layer formed below the pigment layer is exposed and melted, the first resist layer is efficiently exposed to the solvent, One resist layer is removed in a short time. Thereby, the processing time for removing the resist layer is reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A to 1D are sectional views for explaining steps of a method for manufacturing a color filter according to the present invention. These drawings show the same parts as FIGS. 3 (a) to 3 (d). (A) First Step A resist is applied to the surface of a semiconductor substrate 11 on which a plurality of light receiving pixels are formed to form a first resist layer 12 having a constant film thickness. An opening 13 corresponding to the filter pattern is formed by selectively exposing the filter. The semiconductor substrate 1 exposed on the bottom of the opening 13
Pigment layer 1 of a desired color so as to cover the surface of
4 is formed. The steps up to the formation of the pigment layer 14 are the same as the first to third steps in FIG.

(B) Second Step A resist is applied again on the first resist layer 12 on which the pigment layer 14 has been formed, and the opening 13 in the first resist layer 12 is formed.
Is formed to form a second resist layer 15 having a flat surface. No photosensitive treatment is performed on the second resist layer 15. (C) Third Step An etching process using oxygen plasma or the like is performed on the entire surface of the second resist layer 15 having a flat surface, and the second resist layer 15 is uniformly etched until the surface of the first resist layer 12 is exposed. . At this time, the pigment layer 14 formed on the first resist layer 12 is simultaneously etched.

(D) Fourth Step The second resist remaining in the first resist layer 12 and the opening 13 is formed.
An alcohol-based solvent is sprayed at a high pressure toward a part of the resist layer 15 to melt each of the resist layers 12 and 15 so that the substrate 1
1 Completely remove from above. At this time, the first resist layer 12 and the second resist layer 15
When the resist layers 12 and 15 are melted and removed, the pigment layer 14 is torn at the corner rising from the bottom surface of the substrate 11 to the side surface of the opening 13, and the respective resist layers 12 and 15 are separated.
Removed with 15. That is, since the portions other than the portion of the pigment layer 11 that is in close contact with the substrate 11 are subjected to a breaking stress when the respective resist layers 12 and 15 are melted, even if the resist layers 12 and 15 themselves are not melted by the solvent, the resist layers 12 and 15 are taken together with the respective resist layers 12 and 15. Removed. Such lift-off processing can be completed in a short processing time because the solvent is efficiently applied to the first resist layer 12. Accordingly, the specific color component is applied to the surface of the semiconductor substrate 11 corresponding to the desired light receiving pixel without leaving an unnecessary portion of the resist layer 12 or the pigment layer 18 and without damaging the necessary portion of the pigment layer 18. The filter layer 16 corresponding to is formed.

As shown in FIG. 2, a normal color filter has segments C1 to C4 corresponding to a plurality of color components.
, The first to fourth steps are repeated,
The filter layer 19 is formed independently for each color component. In the above embodiment, the case where the color filter is formed on the semiconductor substrate of the solid-state imaging device has been described as an example, but the present invention can also be applied to the formation of the color filter for each display pixel of a display device such as an LCD panel.

[0018]

According to the present invention, when the filter layer is formed by patterning the pigment layer by the lift-off method, unnecessary portions of the resist layer and the pigment layer can be reliably removed from the semiconductor substrate. In addition, since the time required for removing the resist layer can be reduced, the pigment layer remaining on the substrate is less likely to be damaged, and the filter layer can be formed with desired optical characteristics. Therefore, it is possible to prevent deterioration of the characteristics of the light receiving element or the display element on which the color filter is mounted, and to improve the yield in the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining steps of a method for manufacturing a color filter according to the present invention.

FIG. 2 is a plan view showing a configuration of a mosaic type color filter.

FIG. 3 is a cross-sectional view of each process for explaining a conventional method for manufacturing a color filter.

DESCRIPTION OF SYMBOLS 1, 11 Substrate 2 Resist layer 3 Exposure mask 4 Opening window 5, 13 Opening 6, 14 Pigment layer 7, 16 Filter layer 12 First resist layer 15 Second resist layer

Claims (2)

[Claims] 1. A method for manufacturing a color filter, comprising: forming a filter layer having a predetermined pattern on a surface of a substrate on which a plurality of light receiving elements or display elements are arranged and formed. After forming an opening to expose a part of the surface of the substrate by selectively exposing the resist layer to light, the surface of the substrate exposed to the opening is covered to correspond to a specific color component. A first step of forming a pigment layer to be applied, a second step of forming a second resist layer on the pigment layer that fills at least the opening and flattens the surface, and flattens the second resist layer. A third step of exposing at least a part of the first resist layer by etching the first resist layer and a part of the second resist layer remaining in the opening and the first resist layer; No A fourth step of removing together with a part of the pigment layer interposed between the dist layer and the second resist layer. 2. The method according to claim 1, wherein the fourth step includes a step of injecting a high-pressure solvent toward the surface of the substrate to melt the first and second resist layers. Method for manufacturing a color filter.