JPS6032048A - Formation of pattern - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pattern forming method, particularly to a pattern forming method using a highly sensitive photosensitive resin.

Conventional configurations and their problems Submicron processing has become a real issue in response to the demand for finer patterns as integrated circuits become more highly integrated. In the conventional contact UV exposure method using a negative resist made of cyclized rubber and bisazide, the practical resolution limit is 2 μm due to pattern distortion due to resist swelling during development and adhesion with nearby images. That's about it. In order to achieve a processing line width of submicron, there are an electron beam exposure method in which drawing is performed directly on the substrate, a gloximity exposure method using X-rays, and an exposure method using reduction projection using a high aperture lens. In particular, the reduced projection method is advantageous when throughput is important. Currently, a reduction projection method (mercury lamp q-ray 436 nm) using a positive resist made of a novolac resin and a naphthoquinone diazide system is used. However, this process includes the following problems. That is, since a positive resist is used, it is troublesome to set development conditions, and dry etching may not have sufficient selectivity.

Purpose of the Invention The present invention eliminates the drawbacks of using a conventional positive resist in the reduction projection method, and provides a high-sensitivity, high-resolution method sensitive to the Q-line (436 nm) and i-line (365 nm) of the emission spectrum of a mercury lamp. The present invention aims to provide a pattern forming method using a negative resist (which does not swell during development).

Structure of the Invention The present invention utilizes the photodimerization reaction of chalcone groups represented by the above formula. A thin film of a polymer having a chalcone group in its molecule, which is a photosensitive group with an electron-donating group introduced as a substituent, is formed on the substrate, and after irradiating desired areas with ultraviolet light, the unirradiated areas are removed using a developer. The present invention relates to a pattern forming method characterized by elution and development.

Chalcone-based polymers, specifically copolymers of 4゛methacryloylochalcone or 4-methacryloylochalcone and methacrylic acid esters such as methyl methacrylate, butyl methacrylate, and glycidyl methacrylate, have an absorption maximum attributable to the chalcone group of 41 In the case of methacryloylochalcone type, it has a wavelength of 312 nm, and in the case of 4 methacryloylochalcone type, it has a wavelength of 310 nm, causing a trimerization reaction in response to ultraviolet light and making it insoluble in a developer. Therefore, it is useful as a resist for pattern forming methods using ultraviolet light. However, the photosensitive wavelengths are 365 nm and 43 nm.
When 6 nm is used, the sensitivity is insufficient.

Therefore, by introducing a methyl group or a methoxy group, which is an electron-donating group, into the chalcone moiety, the sensitive wavelength can be shifted to a longer wavelength. A methoxy group is effective. In the case of 4-methoxy 4-methacryloylochalcone, the sensitivity wavelength is 342 nm, and in the case of 4°-methoxy 4-methacryloylochalcone, it is 340 nm. Therefore, 4-methoxy41-methacryloylochalcone and 4'-
Considering the adhesion between methoxy-4-methacryloylochalcone and methacrylic acid ester, a pattern with a wavelength of 365 nm using glycidimethacrylate and a copolymer as a resist is clear and has high sensitivity.

The proportion of glycidyl methacrylate to achieve the object of the present invention is usually 50 mo 1% or more, preferably 60 mo 1% or more.

Next, in order to further extend the sensitizing wavelength, various sensitizers were investigated and it was found that 6-nitroacenaphthene, phenanthraquinone, 1,2-benzanthraquinone, etc. were effective. In particular, 1,2 benzanthraquinone can sensitize up to 470nm, and 436n
It was confirmed that it has sufficient sensitivity to wavelengths of m.

The amount of 1,2-benzanthraquinone added to achieve the object of the present invention is preferably 6 to 20% by weight based on the polymer.

Next, we found that it is effective to use a mixture of methyl ethyl ketone and inglobil alcohol as a developer for chalcone resists. 100mI/cr
If methyl ethyl ketone alone is used as a developer in the case of an irradiation dose of 1, the film loss will reach 70% of the initial film thickness in 3 cycles, which is not practical. By adding inglobil alcohol, film deterioration can be prevented and higher sensitivity and resolution can be achieved.

In order to achieve the purpose of the present invention, the amount of Inglobil alcohol added is preferably in the range of 10% by weight to 50% by weight. \Description of Examples Example 1 Each resist shown in Table 1 was coated on a substrate to a thickness of 0.5 μm, and then subjected to a Gribake treatment in air at 150° C. for 20 minutes. Next, a desired portion of the prebaked resist film was irradiated with 365 nm ultraviolet light at an illuminance of 3 m'W and for different irradiation times. Thereafter, development was carried out, and the irradiation time showing a residual film rate of 80% is shown in Table 1. Next, a peeling test using cellophane tape was performed, and the results are shown in Table 1.

Table-1 *○: No peeling. '△ Partial peeling ×: Peeling present As is clear from Table 1, when the resist according to the present invention is used, compared to the conventional chalcone resist,
It was successfully confirmed that the irradiation time was shortened by % to % for a wavelength of 65 nm, and a pattern with high resolution could be obtained. Further, regarding adhesion, it was found that adhesion deteriorated when the content of glycidyl methacrylate was 40 mo1% or less. Furthermore, it was confirmed that similar results were obtained for a copolymer of 4'-methoxy 4-methacryloylochalco/and glycidyl methacrylate.

Example 2 4-methoxy 41-methacryloylochalcone and glycerin
Using dil methacrylate copolymer (copolymerization ratio 20:801 molecular weight 30,000) as a resist, the amount of 1,2 benzanthraquinone added was varied as shown in Table 2, and pretreatment was performed in the same manner as in Example 1. Conducted, irradiation wavelength 436 nm
Irradiation was performed at an illumination intensity of 10 mW/d, and the residual film rate after development was 80.
Table 2 shows the relationship between the change in the amount of 1.2 benzanthraquinone added and the irradiation time.

Table 2 As is clear from Table 2, by adding 1,2 benzatraquinone of the present invention, the irradiation time was 14.47. ,. It was confirmed that high-resolution patterns could be obtained.

Example 3 4-methoxy 41-methacryloylochalcone and glycidyl methacrylate copolymer (copolymerization ratio 20: 80s
Pretreatment was carried out in the same manner as in Example 1 using resists with and without 1.2 benzanthraquinone added to the molecule M200,000). There are 3 things
The pattern was irradiated with 65 nm light for 3 osec (3 osec). These were developed using a mixture of methyl ethyl ketone and impropyl alcohol, which is the developer of the present invention, and simultaneously, for 3 minutes using methyl ethyl ketone as a comparative example. Development processing was performed, and the respective residual film percentages are shown in Table 3.

As is clear from Table 3, it was confirmed that by using the developer of the present invention, the residual film rate was significantly improved and a resist pattern with fewer defects could be obtained compared to when methyl ethyl ketone was used alone.

Effects of the Invention As described in detail above, the present invention has significantly improved sensitivity to wavelengths of 365 nm or 436 nm, making it possible to perform patterning with significantly improved output. Furthermore, by using the developer of the present invention,
A resist pattern with a high residual film rate can be obtained.

Therefore, it is possible to provide a pattern forming method that can be effectively used for microfabrication of semiconductor substrates, ζ mask substrates, and the like.

Claims (4)

[Claims] (1) Form a thin film of a polymer having a chalcone group in its molecule, which is a photosensitive group with an electron-donating group introduced as a substituent, on the substrate, irradiate the desired area with ultraviolet rays, and then use a developer to irradiate the unirradiated area. A pattern forming method characterized by eluating and developing a portion. (2) The pattern forming method according to claim 1, wherein the polymer is a copolymer of 4-methoxy 41-methacryloylochalcone and glycidyl methacrylate. (3) The pattern forming method according to claim 1, wherein the polymer is a copolymer of 4''-methoxy4-methacryloylochalcone and glycidyl methacrylate. (4) The pattern forming method according to claim 2, characterized in that 1.2 benzanthraquinone is added as a sensitizer to the polymer. (@ The pattern forming method according to claim 1, wherein the developer is a mixture of methyl ethyleketone and inglobil alcohol.