JPS617835A - Resist material - Google Patents

Abstract

PURPOSE:To obtain a positive type resist material having high sensitivity and high resistance to oxygen plasma by adding a specified o-naphthoquinone compound to a copolymer consisting of a methacrylate monomer contg. Si and methacrylic acid as a resist material. CONSTITUTION:The methacrylate monomer contg. Si represented by general formula I [where each of R, R' and R'' is alkyl or a (substituted) aromatic group, and each of l, m and n is a positive integer] is copolymerized with methacrylic acid, and the o-naphthoquinone compound represented by formula II (where X is -OH, -OCl, -OF, a group represented by formula III or the like) is added to the resulting copolymer to manufacture the resist material. This resist material is suitable for use in the formation of a high resolution pattern having high sensitivity and high resistance to oxygen plasma with high energy beams such as electron beams or ultraviolet rays.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a positive cast material IC for high-energy machining such as electron beam or ultraviolet silver.

[Prior art and its problems]

Conventionally, high energy beam resist materials have been used for pattern formation in LSI processing processes. Among these, fluorine-containing methacrylate thread polymer is known to have high sensitivity (/X10"-@C/cd) as a positive resist (Patent No. 1034536). However, a highly sensitive positive resist is LSI Polyphenyl methacrylate (PPMA), which has a phenyl group introduced into the side chain to improve plasma processing resistance, has a significant decrease in sensitivity (C2×10”-4°/C4). There are disadvantages.Furthermore, in recent years, in order to realize multi-layered wiring and devices with a three-dimensional array structure, it has become desirable to form a resist pattern on a substrate with steps. Therefore, it is necessary to make the resist film thick in order to cover the step.Furthermore, in order to capture high-speed ions without them reaching the substrate, the resist film must also be thick. However, with conventional resist materials, the resolution decreases as the film thickness increases, making it impossible to form fine patterns. To solve this problem, we have developed a multi-layered resist instead of a single layer. A method has been proposed for forming a fine pattern with a high shape ratio, even if the film thickness is less than or equal to the thickness. That is, a thick film of organic polymer is formed as the first layer, a thin resist film is formed on the second layer, and then high-energy rays are irradiated to the second layer resist, and the pattern obtained after development is masked. This method attempts to obtain a pattern with a high shape ratio by anisotropically etching the organic polymer of the first layer. However, in conventional positive resist materials, even if a phenyl group is introduced into the side chain, the resist material has low resistance to the oxygen plasma used for anisotropic etching and cannot be used as a mask for etching the second N-th layer.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a positive resist material that is highly sensitive and has high oxygen plasma resistance.

(Composition and action) The first resist material of the present invention has the following general formula CI) R' (In the formula, n, R/, R# are an alkyl group or an aromatic group.

It represents one type selected from substituted aromatic groups, and may be the same or different from each other, and consists of a polymer compound represented by @), where l, m, and n represent positive integers,
The resist material No. 1 is made by adding an orthoquinone thread compound represented by the following general formula (II) to the polymer compound represented by the above general formula (I).

So, -X (X is 10H, -007.-OF.

OHOH'! One type selected from Hl is shown. ) First, the polymer compound represented by general formula (I) in the present invention will be explained. As l increases, solvent solubility decreases, and the range of usable developing solvents is expanded to include ketones, which is advantageous for high-resolution pattern formation.Increasing l leads to a decrease in 8i content. However, there are disadvantages such as a decrease in oxygen plasma resistance or a decrease in glass transition temperature (Tg), making the material gum-like and difficult to handle. In particular, when the weight content of 1 silicon is 12% or less, the oxygen plasma resistance is significantly reduced, so 1 is preferably 12 or less.

Further, the carboxyl group represented by -CUOH in the general formula (1) causes crosslinking upon heating, reducing the solvent solubility of the material. Therefore, it becomes possible to use a strong solvent during development, and if the number of 6-paths for high sensitivity increases, crosslinking due to heating becomes less likely, but this leads to a decrease in the 81 content and a decrease in oxygen plasma resistance. For this reason, the number of paths may be the lowest that reduces the solvent solubility of the material, and rL/(vn+n) is less than or equal to a3, preferably 12/N4J.

Furthermore, alkyl groups and aromatic groups in general formula I.

Examples of the i-substituted aromatic group include a methyl group, an ethyl group, a glycidyl group, a vinyl group, a propyl group, and a phenyl group.

naphthyl group, methylphenyl group, crosemethylphenyl group. Examples include vinylphenyl groups, but as the molecular weight of the alkyl group or the aromatic group increases, the silicon content decreases relatively, so a methyl group with a low molecular weight is preferred.

As a manufacturing method of this resist material, Metak R, R'
, R' represents an alkyl group, an aromatic group, or a substituted aromatic group, and 1 represents a positive integer. ) to produce a 81-containing methacrylate monomer and copolymerize it with methacrylic acid.
This may be carried out by a conventional method of placing zobisisobutylontolyl, the above monomers and methacrylic acid in a polymerization vessel aK, degassing and sealing, and then heating.

In addition, if a material containing a substituted aromatic group is available, after producing an 81-containing polymer containing a corresponding aromatic group by the above method,
A substituent may be introduced into an aromatic group by a polymer reaction using a Friedel-Crach reaction or the like.

This first resist material is electron beam, X@.

Deep-UV @ irradiation causes backbone chain scission and shows positive resist characteristics.0 However, when irradiated with ultraviolet 41 (UV) with wavelengths longer than 7F & Atsu, backbone chain scission is difficult to occur and there are complaints of low drying sensitivity. be.

A resist material prepared by adding the ortuna-7-toquinone compound of the general formula (n) to the polymer compound of the general formula (I) is a positive material that can be developed with alkali because the ortuna-7-toquinone compound turns into the corresponding indene carboxylic acid when irradiated with ultraviolet rays. It exhibits resist characteristics and is highly sensitive to ultraviolet silver of 300 nm or more.

In the first resist material, the ortuna-7-toquinone compound serves as an agent for preventing dissolution of the resist in an alkaline solution. The amount of the orthonaphthoquinone compound to be added is generally in the range of 5 to 1% by weight. If it is less than 5%, it will not be possible to suppress the dissolution of the polymer compound in an alkaline solution, and alkaline development will not be possible, and if it exceeds 20%, the silicon content as a resist material will decrease, resulting in poor oxygen plasma resistance. In general, the preferred addition amount is about 10% by weight.

〔Example〕

Although specific examples will be described below, the present invention is not limited thereto.

<Example t> Table 1 shows the resist properties when the copolymerization ratio of trimethylsilylmethyl methacrylate and methacrylic acid was changed. ◎Evaluation of sensitivity and resolution was performed by the following method.

81+>Apply the coating to the Eva to a thickness of about a1μ, l50
J0 min UIIT at °C, prebaked in an air stream @after prebaking - Electron beam irradiation was performed at an accelerating voltage of OKV, and deep ultraviolet irradiation was performed using a tKW Xe-Hg lamp - After irradiation, the results are shown in Table 1. Each was developed with a developing solvent, and the irradiation amount at which the remaining film on the irradiated area became O was defined as the sensitivity. The resolution is when the square pattern is exposed to electron beam and developed.
The evaluation was made based on the length of the side of the smallest square that allowed a pattern to be formed without peeling. In Table 1, for the developing solvent, IP refers to Imp4vir, 'alcohol', and MEK refers to methyl ethyl ketone.

In addition, the etching conditions are power a, W/cj, and gas pressure 2.
The test was carried out at 0 Torr.

In the following margins (Examples 2 to 6), dimethylphenylsilylmethyl methacrylate (Example 7) and dimethylphenylsilylethyl methacrylate (Example 7) were used instead of trimethylsilyl methyl methacrylate.

trimethylsilylmethyl methacrylate (In example φ),
Dimethylphenylsilyl ethyl methacrylate (Example &), ) Limethylsilylpropyl methacrylate (
Table 2 shows the resist properties when Example 6) was used. However, the copolymerization rate of methacrylic acid was set to 0%.

<Example 7> Resist material obtained in Example t (copolymerization ratio with methacrylic acid θ%)
A resist material to which t% was added was obtained.

This was applied to an S1 wafer to a thickness of about a μm and prebaked at 80° C. for 20 minutes. After pre-baking, ultraviolet rays were irradiated using Oak's jet light. After irradiation, each was developed with a developing solution with a ratio of Mike's four-bodied cotton and water of / / , and the irradiation amount was such that the residual film on the irradiated area was 0. was taken as the sensitivity. The irradiated area when the Ortuna 7 toquinone thread compound was not added was above to J 1cdlJ, whereas when it was added, the sensitivity became high as shown in Cloth 3.

Table 3 The structure of the number X of the quinone compound is shown below.

0! Example tN12 A resist material was obtained by adding 79w1% of the toquinone compound [phase] used in Example 7 to the resist material obtained in Examples λ to 6. The sensitivity was determined in the same manner as in Example 7, and the results are shown in Table 1.

Table 1 [Effects of the Invention] As explained above, the resist material obtained by the present invention contains a carboxyl group, so it is crosslinked by heating and its solubility is suppressed, resulting in high sensitivity.

Claims (2)

[Claims] (1) General formula I ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R, R', and R'' represent one type selected from alkyl groups, aromatic groups, and substituted aromatic groups. may be the same or different, and l, m, and n represent positive integers.)
A resist material made of a polymer compound represented by (2) General formula I ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R, R', and R'' represent one type selected from alkyl groups, aromatic groups, and substituted aromatic groups. may be the same or different, and l, m, and n represent positive integers.)
Polymer compounds represented by the general formula II ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (X is -OH, -OCl-, CF, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ Numerical formulas, chemical formulas, There are tables, etc. ▼, ▲mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Indicates one type selected from the following. ) A resist material containing an orthonaphthoquinone compound.