JPS6045202B2 - Manufacturing method of photosensitive resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a photosensitive resin used for producing semiconductor devices, photolithographic masks, printed boards, and the like.

Conventionally, when a photosensitive resin (hereinafter abbreviated as PR) is to have a predetermined viscosity depending on the intended use, for example, in the case of a negative type, the viscosity is adjusted through the following steps. First, raw rubber or synthetic rubber is dissolved in xylene, a solvent. After the raw material is completely dissolved over a long period of time, a cyclization catalyst is added to the raw material system, and the reaction is continued to achieve a predetermined viscosity within a certain period of time due to constraints such as coagulation. When the reaction is sufficiently completed, the cyclized comb liquid layer produced by the reaction and the water layer dehydrated from the raw materials are stirred and mixed to make it easy to separate gel-like substances due to unreacted substances and impurities. This is centrifuged to separate the gel and water, and the cyclized rubber is extracted as a necessary component.

Furthermore, in order to extract and remove metals and separate gel-like substances that could not be removed in the previous step, washing is performed again.
Add an organic solvent and perform centrifugation. The raw material system created in this way is processed in a centrifuge, and a completely transparent separated liquid is separated to create a base material for PR.

Thereafter, an azide-based photosensitizer, which is necessary for PR to cause photopolymerization, is dissolved and added. After dissolution, the washing step is repeated again and a final centrifugation is performed. The filtered waves extracted in this way are called negative-type PR, but since PR at this stage has a fairly high viscosity of around 200C, P (a unit that indicates the viscosity of PR), it is suitable for manufacturing semiconductor devices. It cannot be said that it is a state. Therefore, it is necessary to use a precise viscometer to adjust the viscosity to, for example, about 20 to 90 C, P, which is suitable for manufacturing the required semiconductor device.

Therefore, in this step, the viscosity is adjusted by diluting with a suitable solvent. The PR created in this way is repeatedly filtered, pinned, and packaged to create a complete PR.
Becomes a product. The above is a general method for producing negative PR, but since the PR produced in this way dilutes high viscosity PR to produce low viscosity PR, it is difficult to avoid photopolymerization reaction inhibitors contained in the solvent, especially This allows moisture to be mixed in, and the moisture contained in the PR itself also remains in the PR.

For this reason, when selective exposure of a semiconductor device is performed in PR using this manufacturing method, moisture locally inhibits photopolymerization and causes point defects, so-called pinholes. An object of the present invention is to provide a PR that can reduce the incidence of pinholes after PR application by significantly reducing the amount of water contained in the PR. The method for producing photopolymer resins according to the present invention involves the use of a fairly low viscosity PR prior to final centrifugation.
The product is characterized by forming a PR having a desired viscosity, and then, after centrifugation, treating the product under heating or vacuum to volatilize the solvent and the water content. be.

Therefore, by using the present invention, the water in the solvent is evaporated together with the solvent, and in addition to the solvent, the water remaining during PR is also evaporated. Compared to PR, the amount of moisture can be reduced significantly.

In this way, when photolithography of semiconductor devices is carried out using the PR of the required viscosity made according to the present invention, the incidence of pinholes is considerably reduced compared to the PR made by dilution. can do. Next, one embodiment of the present invention will be described.

Using cis-type natural rubber as a raw material, add a solvent such as xy5-lene to dissolve it to 10%, and add an organic sulfonic acid such as P-toluenesulfonic acid as a cyclization catalyst to this solution for cyclization. Produces rubber by reaction.

Next, this reaction solution is centrifuged to remove impurities and water. Thereafter, xylene 3 is added again and centrifugation is performed to purify this cyclized rubber solution. Next, a diad photosensitive agent is added to the cyclized rubber solution in an amount of 5% based on the weight of the rubber, and approximately the same amount of an organic solvent such as xylene is added to reduce the viscosity of the solution by about 30%.

Subsequently, this solution is centrifuged, and further impurities and water are removed by microfiltration, resulting in approximately 10C-
A negative PR stock solution of P was obtained. Next, add about 40% of this PR stock solution.
The solvent and remaining moisture were evaporated in a dry atmosphere at a temperature of 100°C to 100°C to obtain a negative PR of about 60C-P. Here, it goes without saying that the higher the temperature of the drying atmosphere, the shorter the processing time, and the lower the pressure of the drying atmosphere, the shorter the processing time. Curve 1 in FIG. 1 shows the pinhole generation rate on a wafer basis as a function of viscosity when PR obtained according to the present invention is applied to a semiconductor wafer by spin coating.

This is a marked improvement over the pinhole occurrence rate at all viscosities (as shown by PR curve 2 obtained by diluting the high viscosity to a predetermined viscosity according to the conventional method). it is obvious.

It can be seen that the effect is particularly significant in the low viscosity region. Therefore, with this method, the viscosity is evaporated and the viscosity is adjusted.
When a semiconductor device is manufactured using PR that has been prepared,
Due to effects such as low source of pinholes, product yield is
This will greatly improve the reliability of the product.

As mentioned above, in the manufacturing method of PR used for the purpose of forming precise required patterns for semiconductor devices, photo-etching masks, printed boards, etc., the viscosity is adjusted by diluting the conventional high viscosity. By changing the method of creating PR with a desired viscosity to the method of creating PR with a desired viscosity by concentrating it to a lower viscosity, the water content in PR can be significantly reduced.

Therefore, applying PR created by this method to semiconductor devices, etc. has great industrial value, such as reducing the incidence of pinholes and improving product yield and reliability. There is something.

Although the present invention has been described above in the case of negative-type PR using natural rubber, it goes without saying that the present invention can be widely applied to the production of negative-type PR using various raw materials.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the viscosity of PR and the incidence of pinholes, where curve 1 is the PR according to the present invention and curve 2 is the conventional PR.
The pinhole occurrence rate due to R is shown.

Claims (1)

[Claims] 1. A step of adding an organic solvent to a cis-type rubber material and dissolving it, a step of adding an organic sulfonic acid as a cyclization catalyst to this solution to react and generate a cyclized rubber, and adding a diad photosensitive agent to the cyclized rubber solution. and an organic solvent, and from this solution about 10C. A step of obtaining a negative stock solution of P, and placing the negative stock solution in a high-temperature dry atmosphere to volatilize the organic solvent and water contained in the negative stock solution.
．． 1. A method for producing a photosensitive resin, the method comprising the step of obtaining a photosensitive resin that is a P liquid and is applied to a semiconductor wafer.