JP2541566B2 - Pattern forming material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Regarding a pattern forming material for a semiconductor integrated circuit, when a ladder structure silicone resin having a vinyl group in a side chain and a silyl terminal is used as a resist,
Ladder structure with a vinyl group in the side chain and silylated end groups, with the aim of ensuring a certain high resolution without sacrificing excellent sensitivity and oxygen plasma resistance. The silicone resin is constituted so that a surface tension reducing amount of a surfactant is added.

[Industrial applications]

The present invention relates to a pattern forming material, particularly a pattern forming material for a semiconductor integrated circuit. In particular, the pattern forming material of the present invention can be advantageously used as a negative electron beam resist, particularly as an upper layer resist of a two-layer structure resist method.

[Conventional technology]

Thin film formation technology and photolithography technology (photolithography or electron beam lithography) are frequently used for the formation of semiconductor integrated circuits. Due to the progress of these technologies, semiconductor unit devices are becoming finer and finer, such as LSI and VLSI. Large-capacity elements have been put to practical use.

That is, regarding the wiring pattern, a resist is coated on a thin film made of a wiring forming material formed on a substrate to be processed, and the resist pattern is selectively exposed to ultraviolet rays to form a resist pattern. A pattern forming method for forming a fine pattern by performing etching is known. However, in this method, the formation of a fine pattern is limited to a pattern having a line width of 1 μm or more, and it is difficult to form a fine pattern having a line width of less than 1 μm due to the limitation by wavelength.

On the other hand, ionizing radiation such as an electron beam has a wavelength much shorter than that of ultraviolet rays, and therefore it is possible to form a fine pattern of less than 1 μm. Therefore, electron beam lithography is used for forming a large-capacity element such as VLSI. Is used.

By the way, in a semiconductor device manufacturing process such as LSI, VLSI, etc., a step difference of 1 to 2 μm often occurs on the substrate surface due to the multi-layering. In such a case, the conventional single-layer resist method is applied. Then, even if it is electron beam lithography, it becomes impossible to form a fine pattern with high precision.

What was developed in order to avoid the above problems is to first planarize using a lower layer resist, thinly form an upper layer resist excellent in oxygen-resistant dry etching resistance, and dry-etch it to form a fine pattern. This is a two-layer structure resist method to be formed.

As the upper layer resist of the two-layer structure resist method, a ladder-structured silicone resin having a vinyl group in the side chain and silylated at the end is widely and advantageously used because of its excellent sensitivity and oxygen plasma resistance. . As an example of such a ladder-structured silicone resin, for example, silylated polyvinyl silsesquioxane represented by the following formula can be cited: (N in the formula represents the degree of polymerization).

[Problems to be solved by the invention]

However, the ladder-type silicone resin of the type described above may cause a development residue, and thus the resolution is not always good. Although attempts have been made to improve the developing solution in order to prevent the generation of development residues, satisfactory results have not been obtained yet. Although it is not fully understood why development residues occur in the described ladder structure silicone resin, those having an alkyl group such as a methyl group in place of a vinyl group have lower sensitivity and do not cause residues. Considering this, it is understood that the vinyl group present in the side chain has some action.

The object of the present invention is therefore to always use a ladder-structured silicone resin having a vinyl group in the side chain and silylated at the end as a resist without impairing the excellent sensitivity and oxygen plasma resistance. It is to provide a pattern forming material which can ensure a certain high resolution.

[Means for solving problems]

According to the present invention, the above-mentioned object is characterized in that a surface-reducing amount of a surfactant is added to a ladder-structured silicone resin having a vinyl group in a side chain and a terminal silylated pattern. It can be achieved by the forming material.

The ladder structure silicone resin used in the pattern forming material of the present invention is preferably a silylated polyvinyl silsesquioxane represented by the following formula: (N in the formula represents the degree of polymerization) and others.

 The surfactant used in the present invention is
It is soluble in the solution and has the desired effect of reducing interfacial tension.
It is not particularly limited as long as it is. Useful world
Surfactants include those listed below: Ionic surfactants Anionic types: Carboxylic acid types, eg RCOOM (M = H, Ca, Mg, C₂Etc.), R
SO₂NHCH₂COOH, etc .; Sulfate ester type, eg high-grade alcohol
Sulfuric acid ester salts, etc .; Sulfonic acid type, eg al
Kill sulfonate, amide sulfonate, etc .;
Tell type; Acetate type; Cationic type: Higher amine salt type, such as higher amine resin acid salt; High
Quaternary alkyl quaternary ammonium salt type, eg RSCH₂N (CH
₃)₃Br Amphoteric type: carboxylic acid type, egEtc; sulfate ester type, egSulfonic acid type; Phosphoric acid type, such as lecithin; Nonionic type: Perfluoroalcohol, polyethylene glycol, etc.
Polyhydric alcohol resin acid ester, etc.

These surfactants are added to the ladder structure silicone resin in an amount sufficient to reduce the interfacial tension of the resist when preparing the resist solution. The preferred addition amount of the surfactant is in the range of several hundred ppm to several thousands ppm. hundreds
An addition amount of less than ppm is not preferable because the generation of development residues cannot be suppressed, and an addition amount of more than several thousands ppm can prevent the generation of development residues.
It should be avoided because it causes cracks during baking.

[Work]

The mechanism for preventing the generation and adhesion of the development residue according to the present invention has not been specifically identified. However, in consideration of the results of the research conducted by the present inventors, the surfactant contained in the resist film is effective in preventing the residue from redepositing on the resist film even if a development residue is generated during development. It is thought to be to prevent this. In fact, mixing the surface active agent into the developing solution did not provide the excellent effects of the present invention.

〔Example〕

Example 1 10 g of silylated polyvinyl silsesquioxane (▲
▼ = 5.0 × 10 ⁴ , ▲ ▼ / ▲ ▼ = 1.6) is dissolved in 90 g of methyl isobutyl ketone, and 0.1 mg of acetic acid ester type anionic surfactant is added to this: Sumitomo 3M Limited
FC-431 manufactured by K.K. was added to prepare a resist solution.

On the silicon substrate, the resist of Shipley Co.,
Spin-coat MP-1350 to a film thickness of 2.0 μm, and
Baking at 20 ° C. for 60 minutes. Then, the resist solution prepared above was spin-coated on the resist film so as to have a film thickness of 0.2 μm, and baked at 80 ° C. for 20 minutes.
The resist film thus obtained was irradiated with an electron beam at an acceleration voltage of 20 Kv, developed in acetone for 60 seconds, and then rinsed with isopropyl alcohol for 30 seconds. No development residue was observed during development. As a result, the line width at an electron beam exposure of 5 μC / cm ²
A 0.5 μm fine pattern could be formed.

Example 2 (Comparative Example) The procedure described in Example 1 was repeated, but in this example, no surfactant was added to the resist solution for comparison. Since the surfactant was absent in the resist film, a large amount of development residue was generated during the development, and therefore a pattern having a line width of 1.0 μm or less could not be formed.

Furthermore, for comparison, no surfactant was added to the resist solution, but instead in acetone as the developer.
When 0.01% by weight of the surfactant FC-431 (described above) was dissolved and used, the development residue could not be prevented as in the above case, and therefore the desired fine pattern could be obtained. Couldn't get

〔The invention's effect〕

According to the present invention, when the resist pattern is formed, the ladder structure silicone having a vinyl group in the side chain and silylated at the end is not deteriorated without impairing the excellent sensitivity and oxygen plasma resistance which are the characteristics shown in the figure. It is possible to achieve the desired resolution.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shoji Shiba, 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa 1015, Fujitsu Limited (72) Inventor Yoko Kawasaki, 1015, Kamikodanaka, Nakahara-ku, Kawasaki, Kanagawa, Fujitsu Limited ( 72) Inventor Yasuhiro Yoneda 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited (56) References JP 58-49717 (JP, A) JP 62-75440 (JP, A) JP A 61-279852 (JP, A) JP 62-215944 (JP, A)

Claims (4)

(57) [Claims] 1. A ladder-structured silicone resin represented by the following formula, which has a vinyl group in its side chain and is silylated at the terminal: A pattern-forming material, wherein (in the formula, n represents the degree of polymerization) is added with a surfactant in an amount that reduces the interfacial tension. 2. The amount of the surfactant is several hundreds to several thousands ppm.
The pattern forming material according to claim 1, wherein 3. The pattern forming material according to claim 1, which is used as a negative electron beam resist. 4. The pattern forming material according to claim 3, which is an upper layer resist of a two-layer structure resist method.