JPH02187758A - Pattern forming method - Google Patents

Abstract

PURPOSE:To prevent corner parts of a rectangular part from forming a thick connection even when a diffraction generates at the time of exposure or when a deformation generates after developing where the connecting part becomes thick by forming a light shielding part in between the corner parts, in an area which corresponds with the rectangular part coming into contact at the corner part of an exposure mask. CONSTITUTION:The pattern forming method is carried out by corresponding the light shielding range 1 of the exposure mask to a part to be eliminated by developing a negative type resist, and then the range 1 is formed by making a light shielding film on a surface of a transparent glass substrate, etc. Further, it is made to correspond with the rectangular part to remain after development of the negative type resist of a light transmitting range 2, and the area between the range 2 corresponding to one rectangular part of the negative type resist and the range 2 corresponding to another rectangular part connecting with the rectangular part at the corner part are shielded by a light shielding part 3. This light shielding part 3 is formed integrally with the light shielding range 1, and the width W of the light shielding part 3 is made less than the resist resolution limit to eliminate the generation of a space between the rectangular parts in contact with the corner part of the negative resist pattern.

Description

[Detailed description of the invention] The present invention will be described in the following order.

A. Industrial field of application B9 Overview of the invention C0 Prior art [Figures 4 to 6] Problems to be solved by the invention [Figure 7] Example of means and action for solving the problems [First [Figures 3] Effects of the Invention (A. Field of Industrial Application) The present invention relates to a pattern forming method, particularly to a pattern forming method for forming a checkered pattern using a negative resist.

(B. Summary of the Invention) In the above-described pattern forming method, the present invention provides an exposure mask for sharpening the shapes of the rectangular portions that touch each other at the corner portions of the checkered pattern. In this method, a gap smaller than the resist resolution limit is provided between the corner portions of the corresponding rectangular portions that are in contact with each other.

(C, Prior Art) [Figures 4 to 6] A color solid-state image sensor has a color filter on its surface, and the color filter is as shown in Figures 4 (A) to (D). It is often formed by

(A) First, a negative resist film is formed on the surface of the solid-state image sensor a, as shown in FIG.

The negative resist film is a mixture of natural tough puff materials such as casein and gelatin with dichromate.

(B) Next, the negative resist film is subjected to an exposure treatment, and then immediately developed, and then the remaining portion is dyed, for example, magenta (Mg). C is a magenta portion.

Figure (B) shows the state after the magenta portion is formed.

(C) Next, a negative resist film is formed, exposed and developed, and cyan (Cy) dyeing is performed to form a cyan dyed film d as shown in FIG.

(D) Next, a yellow dyed film e is formed by forming a negative resist film, exposing it to light, developing it, and dyeing it with yellow (YJ2) as shown in FIG. Note that the yellow dyed film e partially overlaps the cyan dyed film d, and the overlapped part becomes a part of the green filter.

In this way, color filters are generally formed by using a negative resist as a base material, exposing it to light, developing it, and then dyeing it. The reason why a negative resist is used as the base material of a color filter is that it is sensitive to exposure light, has high transparency to visible light (wavelength of 400 to 700 nm), and is resistant to dyeing. Although positive resists have photosensitivity, they have poor transparency to visible light and are difficult to impossible to dye, so they are not used.

FIGS. 5(A) to 5(D) are plan views showing the patterns to be formed in the order of formation; FIG. 5(A) shows the pattern after magenta dyeing film C has been formed, and FIG. d shows the pattern after formation; the same figure (C) shows the yellow dyed film e
The pattern after formation is shown. In addition, in the same figure (C), the region G is a region where the yellow dyed film e overlaps the cyan dyed film d, and becomes a part of the green filter.

FIG. 6 is a plan view showing an example of an exposure mask for patterning a negative resist.The mask uses a glass plate as a substrate, and a portion of the negative resist that corresponds to the part where a pattern is to be formed transmits light. In this region f, no light shielding film is formed on the surface of the glass plate, and a region corresponding to a portion where no pattern should be formed is defined as a light shielding region g. A light shielding film is formed in the light shielding region g. This mask is a cyan dyed film d
It goes without saying that since the patterns differ depending on the dyed film to be formed, the exposure masks used also differ.

Conventionally, the pattern of the light-transmitting region f of the exposure mask was completely similar to the pattern to be formed using a negative resist.

(D. Problems to be Solved by the Invention) [Figure 7] By the way, when a negative resist is exposed and patterned using an exposure mask as shown in Figure 6, after development, The negative resist pattern is the seventh
There was a problem as shown in the figure. That is, the rectangular portions h that touch each other at the corners of the negative resist are thickly connected, and the connected portions i, i, . . . are rounded. This is undesirable because it causes a deterioration in the quality of images captured by the solid-state image sensor. This phenomenon in which the rectangular parts h that touch at the corners are connected thickly and the connected parts i, i, etc. become rounded is because the negative resist is made of natural protein and shrinks or shrinks due to changes in humidity etc. This is thought to be caused by the property of expanding and the occurrence of diffraction during exposure.

The present invention has been made to solve these problems, and an object of the present invention is to sharpen the shape of the contacting portions of rectangular portions that contact each other at the corners of a checkered pattern.

(E. Means for solving the problems) In order to solve the above problems, the pattern forming method of the present invention has the following steps:
The exposure mask is characterized in that a gap is provided between the corners of the region corresponding to the rectangular portions that touch each other at the corners, and is equal to or smaller than the resist resolution limit.

(F. Effect) According to the pattern forming method of the present invention, since there is a light-shielding portion between the corners of the corresponding area and the rectangular portions that are in contact with each other at the corners of the exposure mask, diffraction may occur during exposure, and connections may occur after development. Even if a deformation occurs in which a portion tends to become thicker, it is possible to prevent the corners of the rectangular portion from becoming thicker and connected to each other. Moreover, since the size of the light-shielding portion is below the resist resolution limit, there is no risk of cutting off the corners of the patterned negative resist, and the pattern of the negative resist becomes close to the desired pattern. In other words, the shapes of the rectangular portions that are in contact with each other at the corners of the checkered pattern can be made sharp.

(G. Embodiment) [FIGS. 1 to 3] The pattern forming method of the present invention will be described in detail below according to the illustrated embodiment.

FIG. 1 is a plan view showing an example of an exposure mask used in carrying out the pattern forming method of the present invention, and FIG. 2 is a plan view showing an enlarged portion of FIG. 1.

In the drawings, reference numeral 1 indicates a light-blocking area, which corresponds to a portion of the negative resist that is to be removed by development. The region 1 is created by forming a light shielding film on the surface of a transparent glass substrate.

A light transmitting region 2 corresponds to a rectangular portion that should remain after the negative resist is developed, and in the light transmitting region 2, no light shielding film is formed on the surface of the glass substrate.

Reference numeral 3 denotes a light blocking portion that blocks between a light transmitting region 2 corresponding to one rectangular portion of the negative resist and a light transmitting region 2 corresponding to another rectangular portion that contacts the rectangular portion at a corner,
Light blocking regions 1.1, . . . are formed on the body. Such a light blocking section 3 is provided between the corners of each light transmitting region. The width W of the light blocking portion 3 must be less than the resist resolution limit. This is because if the resist resolution limit is exceeded, gaps will be created between rectangular portions that touch at the corner portions of the pattern of the negative resist after development. In addition, the value of the resolution limit of a negative resist on the resist side is 0.5 to 1.2 μm in the current technology. However, the resolution limit value of the mask differs depending on the reduction ratio.

FIG. 3 is a plan view showing a pattern of a negative resist patterned by exposure using the exposure mask shown in FIGS. 1 and 2 and subsequent development; in the same figure, 4 remains after development. It is a rectangular part. As is clear from this figure, each rectangular portion 4 has sharp corners, and an ideal shape in which diagonally adjacent rectangular portions 4.4 are connected at points. This is because, in the exposure mask, there is a light blocking part 3 between the diagonally adjacent rectangular part 4.4 and the corresponding light transmitting area 2.2, so even if diffraction occurs during exposure or deformation occurs after development, Since the connecting portion between the corners of diagonally adjacent rectangular portions 4.4 cannot be thick, and the width of the light blocking portion 3 is less than the resist resolution limit, there is a risk that the corners of the rectangular portions 4.4 may be cut off. This is because there is no such thing.

(H. Effects of the Invention) As described in Section 7 below, the pattern forming method of the present invention is a method for forming a pattern in which rectangular portions are in contact with each other at their corners using a negative resist. The exposure mask used for exposure for patterning is characterized in that the area corresponding to the rectangular part is separated by a light-shielding part having a width equal to or less than the resist resolution limit.

Therefore, according to the pattern forming method of the present invention, since there is a light-shielding portion between the corners of the corresponding area and the rectangular portions that touch at the corners of the exposure mask, diffraction may occur during exposure, and humidity changes after development may occur. Even if a deformation occurs in which the connected portions tend to become thicker, the corners of the rectangular portions can be prevented from becoming thicker and connected. Moreover, since the size of the light-shielding part is below the resist resolution limit, there is no risk of the corners of the patterned negative resist being cut.
The negative resist pattern becomes closer to the desired pattern. In other words, the shapes of the rectangular portions that are in contact with each other at the corners of the checkered pattern can be made sharp.

[Brief explanation of the drawing]

Figures 1 to 3 are for explaining two embodiments of the pattern forming method of the present invention. Figure 1 is a plan view of the exposure mask used, and Figure 2 is a partially enlarged view of Figure 1. FIG. 3 is a plan view showing a negative resist pattern after development; FIGS. 4 (A) to CD) are cross-sectional views showing the technology for forming a color filter, which is the background art, in order of process; 5(A) to 5(C) are also plan views, FIG. 6 is a plan view showing a conventional example of an exposure mask, and FIG. 7 is a patterned mask for explaining the problem to be solved by the invention. FIG. 3 is a plan view of a negative resist. Explanation of symbols 2... Light transmission area of mask (area corresponding to the rectangular part)
, 3... A light-shielding part that separates the light transmitting areas of the mask, 4... A rectangular part of a negative resist. Applicant: Sony Corporation i)

Claims (1)

[Claims] (1) In a pattern forming method in which a negative resist is used to form a pattern in which rectangular portions touch each other at the corners, an exposure mask used for exposure for patterning the negative resist is used as an exposure mask between areas corresponding to the rectangular portions. A method for forming a pattern, characterized in that the patterns are separated by a light-shielding portion having a width equal to or less than a resist resolution limit.