JPS6358402A - Production of color separation filter - Google Patents

Abstract

PURPOSE:To permit desired adjustment of a difference in residual film rate between the peripheral part of a chip and parts except the peripheral part of the chip by using a partial light shielding mask and projecting light in such a manner as to provide a difference between the exposure in the peripheral part of the chip and the exposure in the parts except the peripheral part of the chip and exposing again the resin film. CONSTITUTION:A negative type dyeable photosensitive resin is coated on a wafer segmented to plural pieces of the chips 9 and is dried. A photomask 12 is brought into tight contact with or proximity to the negative type dyeable photosensitive resin film 10 coated on the wafer and light 13 is projected thereto to make the 1st exposure of the resin film 10. The partial light shielding mask 15 is then used and the light 13 is so projected as to provide the difference between the exposure in the peripheral part 16 of the chip and the exposure in the parts except the peripheral part of the chip to make the 2nd exposure of the resin film 10. The uncured parts are thereafter developed and dissolved to form the pattern of the negative dyeable resin which is the residual film on the chip 9. The difference between the residual film rate in the peripheral part of the chip and the residual film rate in the parts except the peripheral part of the chip is thereby adjusted as desired.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention forms a pattern of negative dyeable resin on a plurality of chips on a wafer using a lithography technique, and is applied to a color image sensor. The present invention relates to a method of manufacturing a color separation filter.

[Prior Art] Color image sensors are used in image sensors, video cameras, facsimile machines, 8 mm cameras, etc., and are described in Japanese Patent Publication No. 17375/1983, which features a color separation filter that separates colored light rays. The method for manufacturing color separation filters is to coat an optical glass substrate with a negative dyeable photosensitive resin film, use phosphorography to obtain a predetermined pattern, and then dye this. .

The phosphorography method involves (1) coating a photosensitive resin on a substrate, drying it, and (2) irradiating light by placing a photomask in close contact with or close to the photosensitive resin film coated on the substrate. (3) developing and dissolving the unexposed areas of the photomask pattern to form a negative pattern on the substrate (Science Dictionary, published by Maruzen Co., Ltd. 1985, p. 1436). Please refer).

The invention described in Japanese Patent Publication No. 52-17375 applies this lithography technique to an optical glass substrate, but if this lithography technique is applied to a wafer, a color separation filter for a color image sensor can be manufactured. .

Figures 4A, 4B, and 40 are diagrams showing the case where the lithography method is directly applied to multiple chips on a wafer, and show the cross-sectional appearance of the peripheral part of each chip divided by the dicing line. It is a diagram schematically shown.

FIG. 4A is a diagram showing how a negative dyeable photosensitive resin film 1 is coated on a wafer by spin coating.

A plurality of chips 3 divided by dicing lines 2 are formed on the wafer. Due to the grooves of the dicing line 2, the negative dyeable photosensitive resin film 1 around the chip 3 is recessed.

FIG. 4B shows how the photomask 4 is brought close to the negative dyeable photosensitive resin film 1 in this state and the light 5 is irradiated thereon. The portion 6 indicated by the horizontal line represents the exposed portion. A photomask 4 used to form a color separation filter for a color imaging device has a light-shielding portion 7 so that not only the pattern but also the portion corresponding to the dicing line 2 is not photocured.

Next, the unexposed portions of the photomask pattern are developed and dissolved to form a negative type dyeable resin pattern 8 on each chip 3.

[Problems to be Solved by the Invention] However, when the pattern 8 is formed using the normal lamination lithography method as described above, there is a problem that the film thickness of the pattern in the peripheral area of the chip 3 becomes thinner, as shown in FIG. 4C. will arise. If a color separation filter with a thinner film around the chip 3 is used, the optical density will be lowered, resulting in brighter colors, which is a problem.

On the other hand, there are cases in which the thickness of the film around the chip 3 is actively reduced, but this is a problem because the ordinary lamination lithography method alone is half-hearted and cannot achieve its full effect.

This invention was made in order to solve the above-mentioned problems, and it is a method that prevents the film thickness of the pattern on the periphery of the chip from becoming thinner than the film thickness of the part other than the periphery of the chip. It is an object of the present invention to provide a method that can sufficiently produce the effect when making the peripheral part of a chip thinner.

[Means for Solving the Problems] The method for manufacturing a color separation filter according to the present invention includes the following means.

First, a negative dyeable photosensitive resin is applied to a wafer divided into multiple chips, dried, and a photomask is placed on the negative dyeable photosensitive resin film coated on the wafer. The resin film is exposed to light for the first time by irradiating the resin film with light in close contact or close to each other.

Next, the resin film is exposed a second time by irradiating light using a partial light-shielding mask so as to create a difference between the amount of exposure around the chip and the amount of exposure outside the periphery of the chip. .

Thereafter, the uncured portion is developed and dissolved, and a pattern of the negative dyeable resin as a residual film is formed on the chip.

[Operation] By performing the second exposure using a partial light-shielding mask, it is possible to create a difference between the amount of exposure around the chip and the amount of exposure outside the periphery of the chip. It is possible to adjust the difference between the remaining film rate in the area and the remaining film rate in areas other than the chip peripheral area.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

Figures 1A, IB, IC, and ID are diagrams showing an embodiment of the present invention.

FIG. 1A is a cross-sectional view of the vicinity of the dicing line 11, that is, the area around the chips 9, in the case where a plurality of chips 9 on a wafer are coated with a negative dyeable photosensitive resin film 10 by spin coating. It is.

In FIG. 1B, the photomask 12 is brought close to the state shown in FIG. 1A and light 13 is irradiated to expose the resin film 10. The photomask 12 has not only a pattern but also a light-shielding portion 14 to prevent the portion corresponding to the dicing line 11 from being photocured.

In FIG. 1C, only the peripheral area of the chip is exposed again using a partial light-shielding mask 15.

This partial light-shielding mask 15 has a light-shielding portion 18 designed to allow light to shine only on the chip peripheral area 16 and to prevent light from shining on areas 17 other than the chip peripheral area. Due to this Q shown in FIG. 1C, only the chip peripheral area 16 is re-exposed, and the remaining film rate in this area increases. In the diagram of the chip peripheral area 16, the horizontal line represents the first exposure, and the vertical line represents the second exposure (this method of representation is the same below).

FIG. 1D is a cross section of the remaining film on the chip that was developed.

Generally, the relationship between the exposure amount and the residual film rate of the negative dyeable photosensitive resin is as shown in FIG. For example, in Figure 1B,
The point indicated by A in the figure is exposed, and the exposure amount from A to B in FIG. 1C is added to expose only the peripheral area 16 of the chip. Then, the remaining film rate in the peripheral area of the chip increases by d in FIG.

In this way, using the graph in FIG.
If the second exposure is adjusted so that the residual film rate of No. 6 is equal to the residual film ratio of No. 17 other than the chip peripheral area, and this is developed and the uncured portion is dissolved, the result shown in Fig. 1D is obtained. As shown, a film in which the thickness of the remaining film in the chip peripheral area 16 is equal to the thickness of the remaining film in the area 17 other than the chip peripheral area can be obtained.

In the above embodiment, the second exposure is performed so that the thickness of the remaining film in the chip peripheral area 16 is equal to the thickness of the remaining film in the other part 17. However, the present invention is not limited to this, and only the chip peripheral portion 16 can be raised as shown in FIG. 3A. That is, using the graph in FIG. 2, the chip peripheral area 1
The second exposure dose is adjusted so that the remaining film rate of No. 6 is greater than the remaining film ratio of the portion 17 other than the chip peripheral area. When this is developed, what is shown in FIG. 3A is obtained. By increasing the thickness of only the peripheral portion, the optical characteristics of the color separation filter can be changed.

In addition, in the opposite case of the above embodiment (Fig. 3A), the second exposure is carried out using a partial light-shielding mask that blocks only the dicing line 11 and the peripheral part 16 of the chip at the stage shown in Fig. 1C. For example, it is also possible to proactively make the chip peripheral portion 16 thinner. Figure 3B is a cross section obtained using this method.

By proactively thinning the chip peripheral portion 1B, the optical characteristics of the color separation filter can be changed.

[Effects of the Invention] As explained above, the present invention uses a partial light-shielding mask to irradiate light so as to create a difference between the amount of exposure at the periphery of the chip and the amount of exposure at a portion other than the periphery of the chip. Since the film is re-exposed, the difference between the remaining film rate around the chip and the remaining film rate at parts other than the chip periphery can be adjusted as desired. As a result, it becomes possible to manufacture color separation filters having various optical characteristics.

[Brief explanation of drawings]

1A, 1B, 1C, and 1D are diagrams showing an embodiment of the present invention, and FIG. 1A shows a negative dyeable photosensitive resin film formed on a chip. Figure 1B is a diagram showing the resin film being approached with a photomask and irradiated with light, Figure 1C is a diagram showing the resin film being re-exposed using a partial light shielding mask, and Figure 1D is a diagram showing that the resin film is re-exposed to light using a partial light shielding mask. It is a figure which shows the state after development. FIG. 2 is a diagram showing the relationship between the exposure amount and the residual film rate of the negative dyeable photosensitive resin. FIGS. 3A and 3B are diagrams showing other embodiments of the present invention. Figures 4A, 4B, and 4C are diagrams showing the state in which the ordinary phosphorography method is directly applied to a wafer, and Figure 4A shows a negative dyeable photosensitive resin film on a chip. FIG. 4B is a diagram showing that the resin film is covered with light, and FIG.
Figure C is a diagram showing the state after development. In the figure, 9 is a chip, 10 is a negative dyeable photosensitive resin film, 12 is a photomask, 13 is a light, 15 is a partial light shielding mask, 16 is a chip peripheral area, and 17 is a part other than the chip peripheral area. . Figure 1A Figure 1D Figure 9: 1,000/A Figure 2 @ , tl Figure 3A Figure 38 Figure 4A Figure 4C Procedural amendment (voluntary) 642 Sun, 1988

Claims (4)

[Claims] (1) A negative dyeable photosensitive resin is applied onto a wafer divided into multiple chips, dried, and then photo is applied onto the negative dyeable photosensitive resin film coated on the wafer. The resin film is exposed by irradiating light with the mask in close contact with or close to each other, and then a difference is created between the amount of exposure around the chip and the amount of exposure outside the periphery of the chip using a partial light shielding mask. A method for producing a color separation filter, in which the resin film is exposed to light, and the uncured portion is then developed and dissolved to form a residual film pattern of negative dyeable resin on the chip. . (2) A patent claim in which the amount of exposure of the peripheral area of the chip is greater than the amount of exposure of the area other than the peripheral area of the chip, and the remaining film rate of the peripheral area of the chip is equal to the remaining film rate of the area other than the peripheral area of the chip. A method for manufacturing a color separation filter according to item 1. (3) A patent claim in which the amount of exposure in the peripheral area of the chip is higher than the amount of exposure in the area other than the peripheral area of the chip, and the remaining film rate in the peripheral area of the chip is higher than the rate of remaining film in the area other than the peripheral area of the chip. A method for manufacturing a color separation filter according to item 1. (4) A patent claim in which the amount of exposure of the peripheral area of the chip is lower than the amount of exposure of the area other than the peripheral area of the chip, and the remaining film rate of the peripheral area of the chip is lower than the rate of remaining film of the area other than the peripheral area of the chip. A method for manufacturing a color separation filter according to item 1.