JPH02187701A - Production of solid state image pickup element - Google Patents

Abstract

PURPOSE:To shorten exposing time and to enhance the adhesive property to a substrate so as to improve pattern sharpness by subjecting a negative type resist to exposing and heat treatment, then to developing. CONSTITUTION:A semiconductor wafer 3 on which the solid state image pickup element is formed is coated with the negative type resist in a coating section 1 and is then prebaked in a prebaking section 2 to 80 deg.C. The resist is exposed for 400msec which is half the conventional exposing time by a g ray stepper 4 and is then subjected to the heat treatment for one minute at about 80 to 100 deg.C in a baking section 5; thereafter, the resist is developed in a developing section 6. The thermal polymn. of the exposed part does not progress even if the resist is heat treated at about 80 to 100 deg.C in this way, but the thermal polymn. in the exposed part progresses and, therefore, the pattern maturation which is heretofore executed by resting for one hour is executed in an about one minute and the exposing time is shortened. The adhesive property of the negative type resist to the substrate is enhanced by the heat treatment and the pattern sharpness is improved.

Description

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

A. Field of industrial application B1 Overview of the invention C1 Background art [Figure 2] 09 Problems to be solved by the invention E1 F stage 11 to solve the problems G. Examples [Figure 1] 81 Effects of the Invention (A. Industrial Application Field) The present invention relates to a method for manufacturing a solid-state image sensor, and particularly a method for manufacturing a solid-state image sensor in which a color filter is formed by patterning a negative resist formed on the surface by exposure and development. Regarding.

(B. Summary of the Invention) The present invention provides a method for manufacturing the solid-state image sensor f described above, which improves patterning (pattern sharpness) by shortening exposure time and increasing adhesion to the base. To achieve this, heat treatment is performed for 11 days after exposure and before development.

(C, Prior Art) FIG. 2] A color solid-state image sensor has a color filter on its surface. The color filters are shown in Figures 2 (A) to (D).
It is often formed in a small way.

(A) First, as shown in FIG.
A negative resist film is formed on the surface 1- of a.

DUb is a mixture of natural proteins 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 crosspiece # portion is dyed, for example, with magenta (Mg). C is macenta part 3
, the same figure (B) shows the state after the macenter portion is formed.

(C) Next, a negative resist film d is formed, exposed, developed, and dyed with cyan (Cy) to form a cyan dyed film d as shown in FIG. 2D. .

(D) Next, formation of negative resist Hr2b, exposure,
The same figure (D) was developed and stained with yellow (Y12).
＞A yellow dyed film e is formed as shown in FIG. Incidentally, a part of the yellow dyed film e overlaps with the cyan dyed film 11!2d, or the overlapping part becomes a part of the clean filter.

In this way, color filters are generally formed by using a method of using a negative resist as a TG material, exposing it to light, developing it, and then dyeing it. The use of negative resist as the base material for color filters is due to the exposure light (
It has photosensitivity to ultraviolet rays) and +iJ visual light (400~
This is because it has high transparency to light (with a wavelength of 700 nm) and has a d1 ability for one dyeing.Although positive resists have a photosensitivity of 4F, they have poor transparency to visible light and only 11 dyes. It is not used because it is difficult or impossible.

(Problem to be solved by the invention) By the way, when exposure is performed using a G-line stepper (a sequentially movable reduction exposure device that exposes with G-rays), the exposure time is 1 t per spot.
It will take less than a second (for example, 800m5ec).

Stiffness is approximately two to three times longer than the exposure time for a positive resist film, and becomes a factor that deteriorates throughput. This is because when exposing for patterning color filters using a G-line stepper, one shot can only expose 2 to 4 chips, so even if one shot can expose 4 chips, the OI For example, for a 260-chip wafer, 65 similes are required. and,
Since 10 pieces are made up of 25 wafers, 1
1,625 shots are required per 0 points, and
400m5ec per unit for positive type system [・]
If 1 degree is sufficient, in the case of a negative resist, as mentioned above, it takes about 800 m5ec, so the exposure time ends up being about 10 minutes longer per 10 nits. Especially,
In the case of manufacturing color filters, it is necessary to use a negative resist as the irradiation material, and in the past, this was considered to be an unavoidable problem.

In addition, it has been reported that the negative resist has a poor density with respect to the F base, and the pattern sharpness (pattern sharpness caused by patterning according to the mask pattern) was not sufficient.

Therefore, the inventor of the present invention sought to solve this problem. After repeated research, he came up with the idea that the exposure energy could be reduced by pattern ripening, and furthermore... We searched for a J-method that allows aging to be carried out in a short time, and took on the challenge of eliminating hazing after exposure and before development, which was considered a tab for conventional negative resists.As a result, we developed the present invention. To do 1
゛That's it.

Therefore, an object of the present invention is to shorten the time required for exposure, improve adhesion to the base, and improve pattern sharpness.

(E. Means for Solving the Problems) In order to solve the problems described in L, the manufacturing method of the solid-state image sensor of the present invention includes performing heat treatment (baking) at, for example, about 80 to 100° C. after exposure and before development. Features.

(F. Effect) If the temperature is moderate, such as 80 to 100° C., thermal polymerization of non-exposed portions will not proceed even if the negative resist is subjected to heat treatment after exposure and before development. However, according to this method, polymerization of the exposed portion progresses, so that pattern ripening, which can be achieved by leaving a negative resist for about one hour, can be achieved in a short period of time, for example, once per minute. Therefore, according to the method for manufacturing the solid-state image sensor Y of the present invention, since heat treatment is performed after exposure and before development, the exposure energy can be reduced and the exposure time can be shortened. In addition, the heat treatment can improve the adhesion of the negative resist to the base, and also improve pattern blur.

(G. Embodiment) [FIG. 1] A method of manufacturing a solid-state imaging device according to the present invention will be described in detail below according to the illustrated embodiment.

FIG. 1 is a schematic plan view showing an example of a patterning apparatus used for implementing the present invention. 1, a negative resist is applied to the surface of the semiconductor device on which a large number of solid-state image sensors f are formed.
The coding part 2 is a pre-baking part consisting of a hot plate, and the wafer 3 is coated with a negative resist.
is prebaked in the pre-baked portion 2 at a temperature of, for example, about 80°C. Reference numeral 4 denotes a G-line stepper, which performs exposure processing on the wafer that has undergone preliminary testing. The exposure time for the negative resist with this stepper 4 is 400 m5
ec (0.4 seconds). This exposure time is approximately half the exposure time normally required for negative resists. Therefore, it can be said that the degree of progress of the polymerization reaction is not sufficient at this stage. 5 is about 60 to 100°C (especially 80°C) for the wafer that has been exposed by stepper 4.
°C is preferred. ) is a baking section that performs heat treatment for about 1 minute at a temperature of Conventionally, a patterning device for such a beta 5-point negative type resist has not been provided. This is because, as mentioned above, in the case of negative resists, baking after exposure and before development causes thermal polymerization to occur in non-exposed areas, resulting in a state similar to or close to that of full-surface exposure. be. However, in the present invention, based on the discovery that this risk can be eliminated by adjusting the temperature appropriately, we purposely heat-treated the negative resist after exposure and before development. It was decided to provide the baking section 5 inside.

Then, by this heat treatment in the baking section 5, the polymerization reaction in the photosensitive area can proceed again. That is, the pattern ripening effect that occurs when the pattern is left for about 1 hour after exposure can be obtained by this heat treatment in the beta part 5, and this compensates for the insufficient polymerization reaction caused by shortening the exposure time. be able to. In addition, the adhesion and pattern blur between the negative resist and the base material are also affected.

6 is a developing section;
Development is performed on the wafer 3 that has been heat-treated at 00° C. for about 1 minute. Reference numeral 7 denotes a post-bake section, which performs post-bake at a temperature of about 150"C for each wafer 3 after development. The wafer 3 that has been post-baked in this post-bake section 7 is discharged from the buttering device. .

In the manufacturing method of this solid-state image sensor, C is that by performing heat treatment between exposure and development for patterning the negative resist, the patterning can be performed without any problem even if the exposure time is halved or less. However, if the heat treatment temperature is lower than 60°C, the baking effect will be insufficient. Furthermore, if the temperature of the heat treatment is set to 100° C. or higher, the polymerization reaction may proceed even in areas other than the photosensitive areas of the negative resist, resulting in the possibility that development may become impossible. Therefore, 6
It can be said that heat treatment at a temperature of 0 to 100°C is preferable, and particularly, 80°C is most preferable. This heat treatment can shorten the exposure time, improve the adhesion of the resist to the toe area, and improve pattern sharpness.
It is also possible to prevent uneven development and drying.

(H, Effects of the Invention) As described in 1 above, the method for manufacturing the solid-state image sensor Y- of the present invention provides a solid-state image sensor that forms a color filter by patterning a negative resist formed on the surface by exposure and development. The method for manufacturing the image sensor r is characterized in that the negative resist is subjected to heat treatment after exposure, and then developed.

Therefore, according to the method for manufacturing a solid-state image sensor of the present invention, at a moderate temperature such as 80 to 100°C, even if a negative resist is heat-treated after exposure and before development, thermal polymerization of non-exposed areas occurs. Since polymerization does not proceed or polymerization proceeds in exposed areas, pattern ripening, which can be achieved by leaving a negative resist for about one hour, can be achieved in a short time of, for example, about one degree. Therefore, the exposure energy can be reduced, and the exposure time can be shortened. In addition, heat treatment can improve the adhesion of the negative resist to the base and improve pattern sharpness.

[Brief explanation of the drawing]

FIG. 1 is a schematic top view showing an example of a patterning apparatus used for carrying out the method for manufacturing a solid-state image sensor of the present invention, and FIGS. FIG. Applicant Sony Corporation Patent Attorney Tookawa ~ Akira! 1

Claims (2)

[Claims] (1) A method for manufacturing a solid-state image sensor in which a color filter is formed by patterning a negative resist formed on the surface by exposure and development, characterized in that after the negative resist is exposed, heat treatment is performed, and then development is performed. Method for manufacturing a solid-state image sensor (2) The method for manufacturing a solid-state imaging device according to claim (1), wherein the temperature of the heat treatment is 60 to 100°C.