JPS6347753A - Resist material and formation of pattern - Google Patents

Abstract

PURPOSE:To obtain the titled resist having large dry-etching resistivity and suitable for the two layer resist method by incorporating a silicon contg. styrene polymer composed of a specific structural unit to the titled material. CONSTITUTION:The titled material contains the silicon contg. styrene polymer composed of a structural unit shown by the formula wherein (l) is >=3 an integer, R1, R2 and R3 are each hydrogen atom or 1-3C alkyl group. In the formula, (l) is preferably 3-5, in view of easily synthesizing it and the efficiency of improving the anti-etching property. The pattern obtd. by exposing and processing the resist material has sufficient resistivity as a mask of etching a thick org. high polymer layer by dryetching method, and the pattern- transcribing of the resist material to the org. high polymer is effected with good accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resist material and a pattern forming method,
In particular, the present invention relates to resist materials and pattern forming methods suitable for manufacturing semiconductor integrated circuits, magnetic bubble memories, etc.

[Prior Art] Recently, a two-layer resist method has been proposed as a fine pattern forming method suitable for manufacturing semiconductor integrated circuits, magnetic bubble memories, and the like. In this method, after forming an organic polymer layer on a substrate, a silicon-containing resist layer is provided thereon, and then exposure, development, and transfer are performed to form a fine pattern.

Currently, silicon-containing resists suitable for this two-layer resist method are being actively developed.

Trimethylsilylstyrene or its copolymer has been proposed as a silicon-containing resist that is sensitive to X-rays, electron beams, or far ultraviolet rays (Japanese Patent Application No. 12386/1986).
issue).

[Problem to be Solved by the Invention 1] However, the dry etching resistance of these materials was not necessarily satisfactory.

Generally, if dry etching resistance is insufficient, (1)
Etching conditions during pattern transfer are limited (2)
There are problems such as the etching time becomes long and (3) the mask pattern is not transferred accurately, resulting in so-called pattern conversion differences.

An object of the present invention is to provide a resist material with high dry etching resistance suitable for a two-layer resist method and a method for using the same.

[Means for Solving the Problems] The present invention is based on the general formula: A step of forming an organic polymer layer on a resist material and a substrate comprising a silicon-containing styrenic polymer having a structural unit represented by (1 to 3 alkyl groups); A pattern forming method comprising the steps of forming a resist layer having a predetermined resist pattern on the molecular layer, and dry etching the organic polymer layer using the resist pattern as a mask, wherein the resist layer is formed of the silicon-containing styrene. This is a pattern forming method characterized in that the pattern is formed using a resist material containing a system polymer.

In dry etching using oxygen, there is a strong correlation between the etching resistance and the silicon content of the etched material; the higher the silicon content, the stronger the etching resistance. Since the styrenic polymer according to the present invention contains three or more silicon atoms per constituent unit, it has a high silicon content.

As a result, the etching problems mentioned above can be significantly reduced. The number of silicon atoms in a silicon-containing monomer,
That is, l in the general formula [I] is preferably 3 to 5 from the viewpoint of ease of synthesis and efficiency of improving etching resistance.

The styrenic polymer according to the present invention is synthesized by the following method.

l(2 [A] (where D is a positive integer, then a positive integer of 3 or more, R1,
R2 and R3 represent a hydrogen atom, carbon, or an alkyl group having 1 to 3 atoms. ) After irradiating the silicon-containing styrenic polymer synthesized in this way with X-rays, electron beams, or far ultraviolet rays, only the irradiated portion can be left by imaging with an appropriate organic solvent. One silicon-containing styrene polymer can be used as a so-called negative resist.

Furthermore, in order to apply the resist material of the present invention to a two-layer resist method, first a thick organic polymer layer is provided on a substrate to be processed by a spin-coding method or the like, and then a layer containing the resist material of the present invention is applied. Formed on the organic polymer layer. After drawing a desired fine pattern using the bond, X-rays, electron beams, deep ultraviolet rays, etc., a desired fine negative pattern can be obtained by using an appropriate developer. Using the obtained fine pattern as a mask, the pattern can be transferred to the organic polymer layer by reactive ion etching using oxygen. Thereafter, the workpiece can be etched using the thick organic polymer layer with the fine pattern formed thereon as a mask. Moreover, this thick organic polymer layer can also be used as a mask for ion implantation. Alternatively, application to a lift-off process is also possible.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Synthesis of monomer After purging the inside of the three-hole flask with dry nitrogen gas, 1.5 g (0.06 gram atom) of Grignard magnesium and dehydrated tetrahydrofuran (HF>10 d) were charged.A small amount of ethyl bromide was charged. After adding p-chlorostyrene 8Cl (0.06 mol) and dehydrated dichloromethane HF5 (7
! A solution consisting of was added dropwise with stirring to cause a reaction. Next, while maintaining the temperature at 50 to 60'C, a solution consisting of chlorohebutamethyltrisilane 11.2 (1 m 0.05 mol) and dehydrated dichloroHF 15d was added dropwise to react. After the dropwise addition, heating was stopped and the mixture was stirred for about 1 hour. Next, water 10
(After adding 7!, ether extraction was performed, and the ether layer was dried with tl magnesium. After removing the ether, the desired silicon-containing monomer was obtained by vacuum distillation. Yield: 6.
2C] (42%>. Boiling point 125°C/2 mmHg
.

Synthesis of polymer Silicon-containing monomer synthesized above 5. OC], 30+++ g of azobisisobutyronitrile (AIBN), and 5 d of benzene were charged into a polymerization tube, and after degassing, a polymerization reaction was carried out at 70° C. for 19 hours. After the reaction, a white solid was obtained by pouring the reaction solution into methanol. Fractional purification was carried out using a methyl ethyl ketone-methanol system using a conventional method. Yield 1.5Cl (30%).

The weight average molecular weight determined by gas chromatography analysis is approximately 82,000. The polydispersity was approximately 1.3.

Furthermore, it was confirmed by IR1'H-NMR that the obtained polymer was represented by the following formula.

-4cH2-CH+- (In the formula, n represents a positive integer.) Example 2 1 g of the polymer synthesized in Example 1 was dissolved in 10 ml of xylene to prepare a resist solution. A 0.3 μm thick polymer layer according to the present invention was formed on a silicon substrate by a spin-coding method. Approximately 200 μC/
After cm2 irradiation, it was immersed in a developer solution of THF:ethanol=1=1 for 1 minute and in isopropanol for one classification. As a result, a negative pattern with almost no film loss was obtained on the silicon substrate.

Example 3 A novolac resin resist material MP-1300 (manufactured by Shipley) was coated on a silicon substrate by a spin code method, and heated at 250° C. for 9 A for 1 hour. At this time, M
The thickness of the P-1300 layer was approximately 1.5 mm.

Next, on this M P-1300 layer, the resist solution prepared in Example 2 was used to form a polymer layer according to the present invention having a thickness of 0.3 an inch. As in Example 2, a submicron negative pattern was obtained using an electron beam exposure device.

Furthermore, a reactive ion etching device (manufactured by ANELVA, DE
M-451), oxygen flow ffi5sec,
2. Etching was performed for 12 minutes under the conditions of OPa and 0.16 W/cm2.

As a result of scanning electron microscopy (SEM) observation, it was found that the submicron pattern in the upper layer was accurately transferred to the lower MP-1300 layer.

[Effects of the Invention] As explained above, the resist material of the present invention has excellent dry etching resistance, so the pattern obtained by exposing and developing this resist material is similar to that of a thick organic polymer layer formed by dry etching. It exhibits sufficient resistance as an etching mask, and patterns can be transferred to the organic polymer layer with high precision.

Claims (2)

[Claims] (1) General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, l represents a positive integer of 3 or more, R_1, R_2
and R_3 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) A resist material comprising a silicon-containing styrenic polymer. (2) A step of forming an organic polymer layer on the substrate, a step of forming a resist layer having a predetermined resist pattern on this organic polymer layer, and dry etching the organic polymer layer using this resist pattern as a mask. In the pattern forming method, the resist layer has a general formula: ▲Mathematical formula, chemical formula, table, etc.
and R_3 are the same or different and each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). A pattern forming method.