JPH01262536A - Resist material and its production - Google Patents

Abstract

PURPOSE:To make it possible to form the resist film with a prescribed film thickness and pattern dimension, without generating the striation in the resist film by incorporating the naphthoquinone diazide sulfonate (LMR) of a novolak resin, and gamma-butylolactone in an amount of 12-50wt.% per the LMR, in an org. solvent respectively. CONSTITUTION:The naphthoquinone diazide sulfonate (LMR) of the novolak resin is dissolved in a mixed solution obtd. by mixing the gamma-butylolactone in the org. solvent so as to be 15-50wt.% of the gamma-butylolactone based on the LMR. In this case, the org. solvent is preferably composed of a methyl cellosolve acetate. Thus, the resist film obtd. by applying the org. solution of the methyl cellosolve acetate on an undercoat layer by dropping said solution on a rotating undercoat, does not cause the striation and the changes of the film thickness of the resist film, and the variation in pattern dimension do not occur at the time of forming a pattern.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is applicable to semiconductor devices, other electronic devices, optical devices, stacking devices, etc. The present invention relates to a resist material for forming fine patterns used in manufacturing mechanical devices, etc., and a method for manufacturing the same.

(Conventional technology) Recently, electronics, light, and energy! $1! Microfabrication technology is becoming more and more important in the field of devices such as machines in order to achieve higher degrees of accuracy and miniaturization. In particular, the conditions for increasing the degree of integration of semiconductor devices are becoming stricter. In order to meet the demand for satisfying such conditions, especially in order to carry out microfabrication, it is necessary to apply a resist film by dropping and coating a resist material onto the surface of the substrate, for example, while rotating the substrate to be microfabricated. On the other hand, there is a method in which a resist pattern is formed after an exposure process with electron beams, X-rays, or deep ultraviolet rays, and then these patterns are accurately transferred to the base using dry etching technology using ions and plasma. is needed.

Incidentally, a resist material used in such microfabrication, which is a type of resist material that is dropped and rotated, is naturally required to have high resolution and high dry etching resistance.

Therefore, the inventors of this application
In No. 7842, a resist of naphthoquinonediazide sulfonic acid ester (hereinafter simply referred to as LMR) of novolak resin is dissolved in an appropriate organic solvent and used as a resist material to produce fine resists with high resolution and excellent dry etching resistance. A resist pattern forming method was devised. Note that here, the resist material may refer to the resist itself before being dissolved in an organic solvent or a resist coating solution dissolved in an organic solvent.

(Problems to be Solved by the Invention) However, when attempting to form an LMR film on a silicon wafer, a compound semiconductor substrate, a glass substrate, or any other suitable substrate (hereinafter sometimes referred to as a wafer), When a resist coating solution is applied dropwise onto a rotating substrate and then baked, unevenness called striations are formed as they run radially from the center of rotation of the substrate due to the vaporization of the coating solvent. These striations caused variations in film thickness and pattern dimensions during buttering, making it impossible to transfer the pattern to the substrate as designed. There was a problem.

Therefore, the inventor conducted research on resist materials that do not cause this striation, and found that the LMR (this γ
- It has been discovered that striations do not occur in the resist film when a resist coating solution, ie, a resist material, to which one butyrolactone is added is used.

Therefore, an object of the present invention is to provide a resist material that does not cause striations in the resist film and a method for manufacturing the same.

(Means for Solving the Problem) In order to achieve this object, according to the resist material of the present invention, a naphthoquinonediazide sulfonic acid ester of a novolac resin and a naphthoquinonediazide sulfonic acid ester of this novolak resin are contained in an organic solvent. It is characterized in that it contains γ-butyrolactone in an amount of 12 to 50% by weight based on the weight of the powder.

In addition, in producing the resist material of the present invention, a mixed solution is formed by mixing γ-butyrolactone with an organic solvent, and naphthoquinonediazide sulfonic acid ester of novolak resin is added to the mixed solution, and naphthoquinonediazide sulfonate of the novolac resin is added to the mixed solution. It is characterized by dissolving γ-butyrolactone in an amount t such that the content of γ-butyrolactone is within the range of 12 to 50% by weight based on the acid ester.

In this cyst material and its manufacturing method, it is preferable to use methylcellosolve acetate as the organic solvent. However, it is also effective to use ethyl cellosolve acetate or chlorobenzene as the organic solvent, as well as methyl cellosolve acetate.

Moreover, this γ-butyrolactone is a chemical substance that is easily available.

(Function) In the present invention described above, naphthoquinone diazide sulfonic acid ester (hereinafter referred to as L
It is abbreviated as MR. ) contains γ-butylactone in a certain amount within the range of 12% to 50% by weight. No striations occur in the film, and therefore a resist film can be formed with the designed film thickness and patterning dimensions.

If the content of γ-buty-O-lactone is less than 12% by weight based on LMR, the resist film will not be thinned, but striations will occur, which is not preferable.

If the content of γ-butyrolactone is more than 50% by weight based on LMR, striations will not occur in the resist film, but film thinning will occur, which is not preferable.

(Example) Examples of the present invention will be described below.

It should be noted that although the following examples are described using specific preferred materials, numerical values, or other conditions within the scope of this invention, these are merely illustrative, and therefore, this invention does not cover these illustrative conditions. It should be understood that the terms and conditions are not exclusive.

First, 59 γ-butyrolactone and 9 as an organic solvent.
59 and methyl cell solve acetate to prepare a total binding solution I of 1009.Next, 1M of 409 was dissolved in this mixed solution to prepare a resist coating solution, that is, a resist material. Therefore, in the resist material of this example, the proportion of γ-butyrolactone added to the LMR is 12.5% by weight.

This coating solution was then filtered through a 0.2 um filter. After that, while rotating the base silicon (Sl) wafer at a rotation speed of 1500 rpm (rotation for 7 minutes), the above-mentioned resist material was dropped for 30 seconds and spin coating was performed to form a resist film with a thickness of 1.9 um. did. After that, it was hawked on a hot plate at a temperature of 70"C for 60 seconds. Then, when it was brought to room temperature, the surface of the resist film was observed with the naked eye using an interference microscope. , No striations were observed at all in the periphery of the wafer (illustration is omitted since no striations were generated on the surface of the resist film).

Also, for this resist film, an exposure device lf! with a wavelength of 436 nm (9 lines) was used. After exposure was carried out with an energy of 250 mJ/cm2, development was carried out using a special developer. When the film thickness of the developed resist film was measured using a Cristetub (film thickness measuring device), the film thickness after development was also approximately 1.9 um.
It was confirmed that substantially no film loss occurred.

Although methyl cellosolve acetate was used as the organic solvent in the above embodiments, the same effect can be achieved by using ethyl cellosolve acetate or chlorobezene instead.

Husband healing ■1 In this example, 109 γ-butyrolactone and 909
Mix it with methylcellosolve acetate and bind it all 1
A mixed solution of 009 was prepared.

Next, LMR 409 was dissolved in this mixed solution (1) to prepare a resist coating solution, that is, a resist material. Therefore, in the resist material of this example, the ratio of γ-butyrolactone to LMR is 25% by weight.

With respect to such a resist material, a resist film Ws was formed on a silicon wafer using the same process as in Example I, and the occurrence of striations, reduction in the thickness of the resist film, etc. were investigated. It was confirmed that no striation occurred, and that there was virtually no thinning of the film.

Huyuukan I In this example, 209 γ-butyrolactone and 809
Mix it with methylcellosolve acetate and bind it all 1
A mixed solution (2) of 009 was prepared.

Next, 1M of 409 was dissolved in this mixed solution m to prepare a resist coating solution, that is, a resist material. Therefore, in the resist material of this example, the ratio of γ-butyrolactone to 1M day is 50% by weight.

For such a resist material, a resist film m'i= was formed on a silicon wafer using the same process as in Example ①, and observations such as the occurrence of striae and a decrease in the thickness of the resist film were conducted. As in Example 2, it was confirmed that no striae occurred, and that s'g did not occur substantially.

First, prepare a simple solution of 1009 methylcellosolve acetate as an organic solvent, and add 40q of LMR to this solution.
A resist coating solution, that is, a resist material was prepared by dissolving the resist. Therefore, in the resist material of this example, γ-
Since no butyrolactone is added, the proportion occupied by γ-butyrolactone is 0% by weight.

Next, the same treatment as in Example I was performed. That is, this coating solution was filtered through a 0.2 um filter. After that, the underlying silicon (Si) wafer was rotated at a rotation speed of 1500.
While rotating at rpm (rotation for 7 minutes), the above resist material was dropped for 30 seconds and spin coating was performed to form a resist film with a thickness of 1.9 um. Thereafter, heating was performed on a hot plate at a temperature of 70°C for 60 seconds.

After that, at room temperature, we observed whether striations had occurred on the surface of the resist film using an interference microscope. As shown in the microscopic images shown in Figures 1 (A) and (8), the area near the center of rotation of the wafer was In addition, striations were also observed at the periphery of the wafer.

Thereafter, a wavelength of 436 nm (g
After exposing the image (line) to an energy of 250 mJ/cm', it was developed with a special developer.The thickness of the developed resist film was measured with a Talystep (film thickness measuring device). As a result, the film thickness after development was approximately 1.9um.
It was confirmed that there was no substantial film loss.

Comparison 1 Next, γ-butyrolactone of 49 was mixed with a solution of methylcellosolve acetate of 1009 as an organic solvent, and LMR of 409 was dissolved in this mixed solution to prepare a resist coating solution, that is, a resist material. Therefore, in the resist material of this example, the proportion of γ-butyrolactone added per 1M day is 10% by weight.

With respect to such a resist material, a resist film was formed on a silicon wafer using the same process as in Comparative Example I, and observations such as the occurrence of striae and a decrease in the thickness of the resist film (r) were conducted. Streations similar to those shown in the microscopic reproductions shown in Figures (A) and (B) were observed not only near the center of rotation of the wafer but also at the periphery of the wafer.

Similar to Comparative Example ■, the thickness of the developed resist film was measured using Talystep (film thickness measuring device).
The film thickness after development was also approximately 1.9 um, and it was confirmed that there was no substantial film reduction.

Next, γ-butyrolactone (49) was mixed with a solution of 009 (methylcellosolve acetate as an organic solvent), and LMRt (409) was dissolved in this mixed solution to prepare a resist coating solution, that is, a resist material. Therefore, in the resist material of this example, the proportion of γ-butyrolactone that has not been added to the LMR is 10% by weight.

With respect to such a resist material, a resist film was formed on a silicon wafer using the same process as in Comparative Example I, and observations such as the occurrence of striae and a decrease in the thickness of the resist film were made, as shown in Figure 1 ( Interference S shown in A) and (B)
Streations similar to those shown in the replica of the VW mirror photo were observed not only near the center of rotation of the wafer but also around the periphery of the wafer.

Therefore, as in Comparative Example I, the thickness of the developed resist film was measured using a Talystep (film thickness measuring device).
The film thickness after development was also approximately 1.9 pm, and it was confirmed that there was no substantial film reduction.

Next, γ-butyrolactone of 259 was mixed with a solution of methylcellosolve acetate of 759 as an organic solvent, and the LMR of 409 was dissolved in this mixed solution to create a resist coating solution, that is, a resist material. Therefore, in the resist material of this example, the proportion of γ-butyrolactone added to the LMR is 62.5% by weight.
It is.

For such a resist material, when a resist film was formed on a silicon wafer using the same process as in Comparative Example ① and observations were made for the occurrence of striations and a decrease in the thickness of the resist film, it was found that whether it was striations or It was not observed not only near the rotation center of the wafer but also at the periphery of the wafer.

Thereafter, in the same manner as Comparative Example I, the thickness of the developed resist film was measured using a Tazo step (film thickness measuring device).
The film thickness after development was 1.4 urn, and it was confirmed that the film thickness was reduced by 0.5 um from the initial film thicknesses of 1, 9 u, and m before development.

(Effects of the Invention) As is clear from the above description, according to the method for producing a resist material of the present invention, LMR is dissolved in a mixture obtained by mixing γ-butyrolactone with an organic solvent, Inclusion of γ-butyrolactone for LMR jll12
% to 50% by weight.

According to the resist material of the present invention manufactured in this way, the mechanism by which the effects described below are obtained is not clear, but a resist film obtained by dropping the resist material on a rotating substrate and coating it is not clear. Since striations do not occur in the method, there is an effect that the thickness of the resist film does not vary, and the pattern dimensions during pattern formation do not vary.

Therefore, the resist material and the method for manufacturing the same of the present invention are suitable for use in manufacturing semiconductor devices and other various devices requiring lifeline patterns.

[Brief explanation of the drawing]

FIGS. 1A and 18 are reproductions of interference micrographs for explaining striations that occur in conventional resist films. Figure 1 of the imitation whistle of an interference micrograph of striations (A
) 0.5mm Interference micrograph of striae on the outer periphery of a wafer Reproduction procedure amendment document 1 Indication of the case 1988 Patent Application No. 92050 2 Name of the invention Resist material and its manufacturing method 3 Relationship with the person making the amendment case Patent applicant address (〒-105) 1-9-17 Azabudai, Minato-ku, Tokyo Address 1-20-5 Higashiikebukuro, Toshima-ku, Tokyo
"Detailed Description of the Invention Column" 7 Contents of Amendment As attached (1), Specification, page 8, line 4 to page 8, line 5 [Then, the underlying silicon (Si) wafer is rotated. "speed" is r
After that, this resist solution is dropped onto a silicon (Si) wafer, and the rotation speed is corrected. (2), same, from page 8, line 6 to page 8, line 7, the above-mentioned resist material was dropped for 30 seconds while rotating with the film thickness. Thick J
I am corrected. (3), "Then, the rotation speed of the underlying silicon (Si) wafer" from page 11, line 11 to page 11, line 12.
After that, this resist solution is dropped onto a silicon (Si) wafer, and the rotational speed is corrected to J. (4), page 11, line 13 to page 11, line 14, [while applying the above-mentioned resist material t for 30 seconds and spin coating to form a film thickness of 1.9 umJ. .Corrected to 9umJl.

Claims (2)

[Claims] (1) In an organic solvent, a naphthoquinonediazide sulfonic acid ester of a novolac resin and a 12 to 50%
1. A resist material containing γ-butyrolactone within a range of % by weight. (2) A mixed solution is formed by mixing γ-butyrolactone in an organic solvent, and the naphthoquinonediazide sulfonic acid ester of the novolac resin is added to the mixed solution, and the content of γ-butyrolactone is added to the naphthoquinonediazide sulfonic acid ester of the novolac resin. A method for producing a resist material, characterized in that the resist material is dissolved in an amount in a range of 12 to 50% by weight.