JPH022567A - Resist pattern forming method - Google Patents

Abstract

PURPOSE:To form fine resist patterns which are hardly deteriorated with age by using polyorganosyl arylenesiloxane as the intermediate layer of a resist having a three-layered structure. CONSTITUTION:The polyorganosyl arylenesiloxane is used as the intermediate layer of the resist having the three-layered structure. The polyorganosyl arylenesiloxane referred to here has the structure in which the arylene group shown by R2 constitutes the main chain by the arrangement -Si-O-Si-R2- or makes crosslinking by the arrangement of R2 between Si arranged in two rows in -Si-O-Si-O- and X directions, as shown by examples of Fig. (A) and (B). The resist patterns which are not deteriorated with age and have high resolution are formed in this way.

Description

[Detailed Description of the Invention] [1 Already Required] Regarding the intermediate layer constituting the three-layer resist, the purpose of forming a stable and high-resolution resist pattern on a processed substrate with steps is to create a three-layer resist. TECHNICAL FIELD The present invention relates to a method for forming a three-layer resist pattern using a polyorganosylarylene siloxane as an intermediate layer of the resist.[Industrial Application Field] The present invention relates to a method for forming a three-layer resist pattern using a polyorganosylarylene siloxane as an intermediate layer.

[Conventional technology]

Thin film formation technology and photo-etching technology (photolithography or electron beam lithography) are often used to form semiconductor integrated circuits, and advances in these technologies have made it possible to
The number one element is becoming increasingly finer, and large-capacity elements such as LSI and VLSI are being put into 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 this is selectively exposed to ultraviolet FrfA and then developed to create a resist pattern. A method of forming a fine wiring pattern by performing wet etching or dry etching, or by narrowing the diameter of the electron beam to an ultra-fine size.
A method is used in which a resist pattern is created by scanning and developing a resist, and a fine wiring pattern is formed by etching.

However, in the manufacturing process of semiconductor devices such as LSI and VLSI, steps of 1 to 2 μm often occur on the substrate surface, and in such cases, applying a conventional single-layer resist makes it difficult to form fine patterns with high precision. becomes impossible.

That is, in the formation of fine patterns, in the case of ultraviolet light exposure, deformation and distortion of the pattern due to scattering and reflection of light and the appearance of standing waves cannot be ignored.

Furthermore, in the case of an electron beam, the pattern is deformed due to the spread of the electron beam incident on the resist film.

Such problems can be avoided by forming the exposed resist layer into a thin film.

Therefore, a two-layer resist is used, in which a lower resist is used to planarize the resist, and a thin upper resist with excellent oxygen dry etching resistance is formed on top of the resist, and a fine pattern is formed by dry etching, or a lower resist is used to flatten the resist. A three-layer structure resist is used in which a fine pattern is formed by forming an intermediate layer with excellent oxygen dry etching resistance, and then forming an upper layer resist on top of this and dry etching it. .

In other words, the three-layer resist has a configuration in which the required characteristics of the upper resist of the two-layer resist are functionally separated into the middle layer and the upper layer, and therefore the upper resist does not necessarily need to have oxygen plasma resistance, which is different from the conventional one. Resist can be used.

Conventionally, silicon dioxide (5iO
z) A spin-on glass (abbreviated as 5OG) film, which can be formed by I-type or spin code, was used.

However, the CVD method has the disadvantage that the process is complicated, and the silicone resin constituting the SOC is likely to change over time because it contains a large amount of highly reactive functional groups.

[Problem to be solved by the invention]

A 5i02 film or a soG film is used as an intermediate layer of a three-layer resist.

However, as mentioned above, there is a problem in that the spin code method cannot be used, or the SOC film for which the spin code method can be used is susceptible to deterioration over time.

Therefore, spin codes are possible and stable;
The challenge is to put into practical use a material with excellent oxygen plasma resistance.

[Failure to solve the problem]

The above problems can be solved by using polyorganosylarylene siloxane as the intermediate layer of the 3Im JM resist.

[Effect]

The present invention uses polyorganosylarylene siloxane as the intermediate layer of a three-layer resist.

Here, polyorganosylarylene siloxane is the first
In figures (8) and (B) - as shown in the example I? , the arylene group shown as 13i-0-5i-112- forms a main chain, or the R2 is arranged between -5i-0-St-0- and Si arranged in two layers in the X direction. It has a structure in which it is arranged and crosslinked.

Here, the polyorganosylarylene siloxane having the structure shown in FIG. 1(A) is known, but the structure shown in FIG.
The polyorganosylarylene siloxane shown in 3) is not known.

The inventors can efficiently manufacture the product using a simple method,
It is less susceptible to oxidative deterioration when heated, and because it dehydrates less during curing, it can form a flexible film with low crosslink density, making it a suitable material for glabellar insulation when manufacturing semiconductor devices. An application has been filed for polyorganosylarylene siloxane with the structural formula shown in (1'3).

(Subject: "Organosilicon polymer, method for producing the same, and semiconductor device using the same" filed on February 27, 1988) Polyorganosylarylene siloxane whose structural formula is shown in Figures 1 (A) and (B) The arylene group constituting may be any divalent aromatic group, but it is convenient to have an FQ structure such as p-phenylene group or m-phenylene group.

In addition, polyorganosyl ary range low structure j1″L
The content ratio of arylene groups in the molecular chain at position is 2
It is desirable to include at least 5 footrests.

Next, polyorganosylarylene siloxane is 275
It has an absorption band caused by the aromatic ring centered around 284 nm, and when a resist pattern is formed by exposing the upper layer using an excimer laser using krypton fluoride (KrF) as a light source, the oscillation wavelength is 284 nm. Since it is 5 nm thick, it absorbs Rayleigh' light and acts as an antireflection film, which can alleviate pattern deformation.

〔Example〕

Synthesis example of polyorganosylarylene siloxane (corresponding to Figure 1 B): Put 100 cc of methyl isobutyl ketone, 50 cc of methyl cellosolve acetate and 30 cc of water into a 300 cc fourth flask, and add 15 ml of triethylamine as a catalyst.
cc was added, and the mixture was cooled to -65°C while stirring.

Separately 1,4-bis(methyldichlorosilyl)benzene l
Og was dissolved in 50 cc of tetrahydrofuran and added dropwise into the flask over 30 minutes.

After the addition, the system was heated to 75° C. at a heating rate of 1.0° C./min and stirring was continued for 2 hours.

After cooling, the system was transferred to a 500 cc separatory funnel, 100 cc each of water and methyl isobutyl ketone were added, stirred, allowed to stand, and the lower aqueous layer was removed.

Next, the organic layer was returned to the flask, heated and stirred, and residual water was completely removed by azeotropy.

Next, the solvent was replaced with ethyl cellosolve acetate, and 12
After stirring at 0°C for 1.0 hour, the reaction solution was poured into a large amount of water to precipitate the polymer, and the polymer was collected by filtration.
A white powder of polydimethyl-p-silphenylene disiloxane (g) was obtained.

Then, as a result of measuring the weight average molecular weight by CPC, it was found to be 7
．． It was 5 XIO'.

Example: 1 g of polydimethyl-p-silphenylene disiloxane obtained by the above method was mixed with 15 mjl of methyl isobutyl ketone!
An intermediate layer solution was prepared by dissolving the mixture in

Pre-J', after applying "Microposit 1350 resist" manufactured by Shisopra Co., Ltd. so that the film JW becomes 2 μm on the Si wafer to flatten the steps on the wafer, 2.

Heating was performed at OoC for 1 hour to cure and form a lower resist.

On top of that, the resist solution prepared earlier was applied to a film thickness of 0.

After coating to a thickness of 2 μm, the intermediate layer was prepared by heating at 200°C for 1 hour to cure.

Next, as an upper layer resist, Fujitsu Research New Co., Ltd.'s positive sub-electron beam resist l-CMI? was applied to a film thickness of 0.2 μm, and after drying the solvent, electron beam exposure and development were performed.

Next, using the upper resist as a mask, carbon hexafluoride (C3
Fg) The intermediate layer was etched with gas, and the upper layer pattern was transferred to the intermediate layer.

Furthermore, the lower resist layer was etched using O2 gas using this intermediate layer as a mask, and the intermediate layer pattern was transferred to the lower layer.

As a result, the resist pattern thus formed was able to resolve lines and spaces of 0.2 μm.

In this example, an example of using polydimethyl-p-sylphenylene disiloxane was described, but the same applies to all cases where polydimethyl-m-sylphenylene disiloxane is used (see FIG. 1(A)). The same applies to the case of using the polyorganosyl arylene salt F-san shown in the following.

〔Effect of the invention〕

By forming a resist pattern with a three-layer structure using the polyorganosylarylene siloxane shown in FIG. 1 (Δ) and (B) as an intermediate layer, it is possible to form a resist pattern that does not change over time and has a high resolution. .

[Brief explanation of the drawing]

FIGS. 1(A) and 1(B) are the structural formulas of polyorgancine siloxane. Silua [bi, -3 is OV2 (f'?2) V2 Rui aL bi+tiH, C43. C2H5,7L-C3Hz SueC
5H7,0HOCA3,0C2Hs, 0-7L-C3t
h, o-, 1-Cat-17 Pi 2 (= Arashi knobral (positive number 310-50000)

Claims (2)

[Claims] (1) A method for forming a resist pattern, characterized in that polyorganosylarylene siloxane is used as an intermediate layer of a three-layer resist. (2) A method for forming a resist pattern, wherein the arylene group constituting the polyorganosylarylene siloxane is a paraphenylene group or a metaphenylene group.