JPS62135823A - Resist composition and pattern forming method - Google Patents

Abstract

PURPOSE:To strengthen a dry etching durability of the resist composition by comprising a specific styrene polymer into the titled composition. CONSTITUTION:The titled resist composition comprises the styrene polymer shown by the formula. Said styrene polymer is composed of a monomer contg. a chloromethyl group and a monomer contg. a silicon atom. The chloromethyl group has an effect of giving sensitivity to the resist, when the styrene polymer is used for the resist. The more the chloromethyl group is contained in the styrene polymer, the higher sensitivity of the resist composition is obtd. The introduction of the chloromethyl group into the styrene polymer depresses the dry etching durability. As the higher the content of the chloromethyl group is, the more the effect of increasing the sensitivity reduces remarkably, the value of (m)/(n+m) is preferably 0.01-0.2. Thus, the titled composition shows sufficiently the durability as a mask, when a thick org. high polymer layer is etched, and the transfer of the pattern to the org. high polymer is effected with a high accuracy.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a resist composition and a pattern forming method, and particularly to a resist composition and an arm turn forming method suitable for manufacturing semiconductor integrated circuits, magnetic bubble memories, etc. It is.

[Conventional technology]

Recently, a two-layer resist method has been proposed as a method for forming fine/l turns 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 on top of the substrate, and then exposure, development, and transfer are performed to form four fine turns. 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 sensitive to X-rays, electron beams, or deep ultraviolet rays for use in this method (%
Gansho 57-123865).

[Problem that the invention seeks to solve]

However, the dry etching resistance of these materials is not always satisfactory. In general, when dry etching resistance is insufficient, (1) etching conditions during pattern transfer are limited, (2) etching time becomes longer, and (3) the mask pattern is not transferred accurately, resulting in so-called pattern conversion differences. arise, etc. problems.

An object of the present invention is to provide a resist composition suitable for a two-layer resist method and having strong dry etching resistance, and a method for using the same.

[Means for solving problems]

The present invention comprises a step of forming an organic polymer layer on a resist composition and a substrate made of a styrene polymer represented by the following general formula, a step of forming a resist composition layer on the organic polymer layer, It consists of a step of forming a desired pattern on the resist composition layer using lithography technology, and a step of dry etching the organic polymer layer using the nine turns as a mask. This is a pattern forming method using a resist composition made of the shown styrenic polymer.

General formula (where n and m represent positive integers, R, , R2, R3
, R4°R5 represents a lower alkyl group or a hydrogen atom. ) [Function] The styrenic polymer according to the present invention is composed of a monomer containing a chloromethyl group and a monomer containing a silicon atom. The chloromethyl group is effective in providing sensitivity when the styrenic polymer according to the present invention is used as a resist, and the more chloromethyl groups there are, the higher the sensitivity becomes. However, since the introduction of chloromethyl groups leads to a decrease in dry etching resistance, which will be described later, it is preferable to introduce as few chloromethyl groups as possible.

Also, in terms of sensitivity improvement, the effect decreases dramatically as the amount introduced increases, so the value of m/(n+m) is 0.
．． It is preferably about 0.01 to 0.2. On the other hand, in dry etching using oxygen, there is a strong correlation between the etching resistance and the silicon content of the material to be etched.
The higher the silicon content, the stronger the etching resistance.

Since the styrenic polymer according to the present invention contains a large amount of monomer containing two silicon atoms, it has a large silicon content.

As a result, the etching problems mentioned above can be significantly reduced.

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

town kc5 (in the formula, n and m represent positive integers, R1* R2, R
3+ R4vR5 represents a lower aryal group or a hydrogen atom. ) After irradiating the styrenic polymer synthesized in this way with X-rays, electron beams, or deep ultraviolet rays, only the irradiated portion can be left behind by developing it with an appropriate organic solvent. The styrenic polymer can be used as a so-called negative resist.

Furthermore, in order to apply the Lenost composition of the present invention to the two-layer resist method, first a thick organic polymer layer is provided on the substrate to be processed by spin coating, and then the resist composition of the present invention is applied. A layer is formed on the organic polymer layer. Thereafter, desired fine/? After drawing the turns, a desired fine negative pattern can be obtained by using a suitable developer. Using the obtained fine noreen as a mask, nogturn transfer can be performed on the organic polymer layer by reactive ion etching using oxygen.

Thereafter, the corrugated material can be etched using the thick organic polymer layer with the fine pattern formed thereon as a mask. Further, this thick organic polymer layer can also be used as a mask for ion implantation. Alternatively, it can also be applied to a lift-off process by taking advantage of the fact that a thick polymeric organic layer can be obtained.

〔Example〕

Hereinafter, the present invention will be explained in detail based on Examples.

(Example 1) (1) Synthesis of monomer H3CH3 was synthesized in the following way.

After replacing the inside of the flask with dry nitrogen gas, 1.0.9 g of Grignard magnesium (0.04 gram atom) and 10 m of dry TIIF were charged. After adding a small amount of ethyl bromide, p-real styrene 4 f! (0,
A solution consisting of 03 mol) and 50 ml of dry THF was added dropwise for one reaction.

Then, while maintaining the temperature at about 50°C, 1-chloro-3-ethyltetramethyldisiloxane 4N (0.02 mol)
A bath solution consisting of 15 mJ of dry THF was added dropwise to cause a reaction. After the dropwise addition, the mixture was stirred at room temperature for about 1 hour. Next, add 1 portion of water
After adding 001117, ether extraction was performed and the ether extract was dried with magnesium sulfate.

After removing the ether, the product was obtained by vacuum distillation. Yield 2.
7.9 (yield 51 cm), boiling point 107-110°C/4II
IIf (g was 0) (2) Synthesis of polymer 2.4, li', chloromethylated styrene 0.15.9. After preparation and deaeration, 7
The polymerization reaction was carried out while maintaining the temperature at 0°C for 15 hours. After the reaction, a white polymer was obtained by pouring the reaction solution into MeOH.

Fractional purification was performed by a conventional method using MEK-MeOH system. The yield was 1.1 (yield 47%).

The weight average molecular weight determined by GPC was about 85,000, and the polydispersity was about 1.4. Also, from 'H-NMR,
It was confirmed that the polymer had the following composition.

CH, CH.

(Example 2) Polymer II synthesized in Example 1 was dissolved in xylene lQm/ to prepare a resist solution. A 0.2 μm thick polymer layer according to the present invention was formed on a No. 81 substrate by spin coating. Approximately 20 μC/cm” using an electron beam exposure device
After irradiation, it was immersed in a developer solution of THE':lil:tOH=1:1 for 1 minute, and then in isopro-gunol for 1 minute.

As a result, a negative pattern with almost no film periphery was obtained on the Sl substrate.

(Example 3) A dinovolac resin layer was formed on an 81 substrate by a spin coating method, and heat-treated at 250° C. for 1 hour. At this time, the thickness of the nogelac resin layer was about 1.5 μm. Then,
On this nogelac resin layer, a polymer layer according to the present invention having a thickness of about 0.2 μm was formed using the resist solution prepared in Example 2. In the same manner as in Example 2, a submicron negative turn was obtained using an electron beam exposure apparatus. Furthermore, one reactive ion etching device (DEM- manufactured by Anelpa)
451) with an oxygen flow rate of 5 SCCM, 2. O
Etching was performed for 7 minutes under the conditions of 0.16 W/cm'' Pa and 0.16 W/cm. As a result of SEM observation, it was found that the submicron pattern on the upper layer was transferred to the lower layer with good accuracy.

(Effects of the Invention) According to the present invention, a negative resist composition made of a styrene polymer containing silicon atoms is obtained, and furthermore, a pattern obtained by exposing and developing the resist composition of the present invention is It has sufficient resistance to dry etching and can be used as a mask when etching thick organic polymer layers.
This has the effect of accurately transferring a pattern to an organic polymer layer.

Percentage applicant: NEC Corporation

Claims (2)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, n and m represent positive integers, R_1, R_2,
R_3, R_4, and R_5 represent a lower alkyl group or a hydrogen atom. ) A resist composition comprising a styrenic polymer represented by: (2) Forming an organic polymer layer on the substrate, forming a resist composition layer on the organic polymer layer, and forming a desired pattern on the resist composition layer using lithography technology. and a step of dry etching the organic polymer layer using the pattern as a mask.The resist composition has a general formula, a mathematical formula, a chemical formula, a table, etc. (where n and m are positive integers. represents R_1, R_2,
R_3, R_4, and R_5 represent a lower alkyl group or a hydrogen atom. ) A pattern forming method characterized by using a resist composition made of a styrene polymer.