JPS6243426A - Alkali-soluble silmethylene polymer - Google Patents

Abstract

PURPOSE:The titled polymer, consisting of constituent units expressed by a specific structural formula, having the backbone chain of silmethylene skeleton and phenolic hydroxyl groups in the side chain thereof, capable of forming films, having improved oxygen plasma resistance and suitable for photosensitive, radiosensitive materials, etc. CONSTITUTION:An alkali-soluble silmethylene polymer consisting of constituent units expressed by formula I [R1-R3 are monofunctional organic group; R4 is alkyl; l is 1 or 2; m and n are positive integers; m+n=2-200; n/(m+n)>=0.4]. For example, the polymer is obtained by reacting a dihalogenosilane expressed by formula II (X1 is halogen or alkoxy), etc., with a Grignard reagent expressed by formula III (X2 is halogen) to synthesize a monohalogenosilane expressed by formula IV, etc., halogenating th resultant compound by photochorination or using N-chlorosuccinimide, etc., to form a compound expressed by formula V, polymerizing the resultant compound expressed by formula V with a metal, e.g. Mg, to give a polymer expressed by formula VI and converting the protecting group OR4 into OH group utilizing reaction of trimethylsilyliodine/methanol, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a novel polymer that is extremely useful as a functional polymer material such as a light and radiation window responsive material. More specifically, it relates to an alkali-soluble silmethylene polymer consisting of structural units represented by the following general formula (11).

General formula 1ll (However, in general formula (11, R+, Rz, and R3 represent a monovalent organic group, R4 represents an alkyl group, OHi and OR, the number l of i is 1 or 2, and any benzene ring Position, m, n is 2-200, n/(m + n)
is 0.4 or more. ) [Background of the Invention] Microfabrication technology by etching using light and radiation is used in the production of electronic components such as semiconductor elements and integrated circuits, and currently the resist material for this is excellent in sensitivity. Alkaline-developable resists containing an alkali-soluble polymer such as phenol resin or polyvinylphenol as a basic polymer are the mainstream. For example, it is widely known that a composition of a novolac resin and a quinonediazide is a positive resist, and a composition of polyvinylphenol and a bisazide is a negative resist. On the other hand, as the wiring of semiconductor devices and the like becomes finer, dry etching is increasingly being used instead of the conventional wet etching for etching the underlying layer after patterning the resist layer. Therefore, resist materials are required to have strong resistance to dry etching.

For example, when the underlying material is organic, it is etched by oxygen plasma, but conventional resist materials have poor resistance to oxygen plasma (there has been a strong desire to improve this property).

In addition, as for the literature on alkali-developable resists, J. C. Strieta: Kodanok Microelectronics Seminar Proceedings (J.
5trieter: Kodak Microel
ec-keonics Sem1nor Procedure
dings) 116 (1967).

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide an alkali-soluble polymer with excellent oxygen plasma resistance.

[Summary of the invention]

Organosilicon polymers are well known as polymers with excellent oxygen plasma resistance. This is because organosilicon polymers are highly efficient when exposed to oxygen plasma (converting into a silicon oxide film, and this silicon oxide film acts as an oxygen plasma resistant film.On the other hand, as alkali-soluble polymers, novolak resin and polyvinyl Polymers having phenolic hydroxyl groups such as phenol are known. Therefore, in order to achieve the above object, the present inventors developed a polymer having a silmethylene skeleton in the main chain and a phenolic hydroxyl group in the side chain. As a result of various syntheses, it has been found that a polymer consisting of a structural unit represented by the following general formula (11) satisfies the above object.

General formula (1) Here, in the general formula (11, Rl + R2+ and R1 are monovalent organic groups, such as hydrogen, alkyl groups, vinyl groups, aromatic groups, and substituents thereof, etc.
1 and R2 are preferably alkyl groups, and C1-
More preferred is a C4 alkyl group.

As for R3, hydrogen is preferred. Furthermore, R4 represents an alkyl group, preferably a C0 to C6 alkyl group. 0l
-II and OR, group scatter! is 1 or 2, and may be at any position on the Hensen ring. m and n are positive integers, m+n is 2 to 200, and n/(m+n) needs to be 0.4 or more in order to be alkali soluble.

The polymer of the present invention (11 is generally represented by formula (2)).

It is synthesized according to formula (3)1, formula (4), and formula (2) (5).

+dl (e) Here, Xl represents a halogen or an alkoxy group, x2 represents a halogen, and M represents a metal. First, in formula (2), monoalkoxylan or monoalkoxylan (C1) is synthesized using dihalogenosilane or dialkoxylan (a) and Grignard reagent (bl. Then, in formula (3),
The Henschel hydrogen in (C) is halogenated to obtain (di).

At this time, photochlorination, N-chlorosuccinimide, N-bromosuccinimide, etc. can be used. In formula (4), a metal is used (di is polymerized to form tel. Magnesium or an alkali metal is used as the metal. When magnesium is used, the polymer skeleton is arranged in the order of Si and C, but alkali When a metal is used, 5i-Si bonds and C-C bonds also enter the polymer skeleton. Therefore, the polymer skeleton of -i formula (1) contains not only 5i-C bonds (, 5i-Si bonds and C- It has a structure that also contains a C bond.Finally, in formula (5), the OR4 group is converted.The protecting group can be cleaved using various reactions such as trimethylsilyl iodo/methanol.Also, 1-butyldimethylsilyl The OH may be protected with a silyl group having a large steric hindrance, such as a silyl group, and then removed with an acid in the final step.

The polymer of the present invention is soluble in alkaline water, such as an aqueous tetramethylammonium hydroxide solution, while being soluble in general-purpose R solvents, such as alcohol-based, ether-based, amide-based, ketone-based, ester-based, cellosolve-based, etc. Since it is easily dissolved in organic solvents, films can be formed using these solutions.

Therefore, like conventional alkaline development resists, this polymer can also be used as a positive photoresist when combined with O-quinonediazides, and as a negative photoresist when combined with bisazides. Furthermore, this polymer can also be used as a positive radiation resist in combination with poly(olefin sulfone).

On the other hand, since the polymer of the present invention exhibits extremely high dry etching resistance without causing film burr in oxygen plasma, the above resist can be used as an upper layer resist in a two-layer resist method.

[Embodiments of the invention]

The present invention will be specifically explained below with reference to Examples.
The invention is not limited to the examples.

Example 1: Synthesis of poly(l,1-dimethyl-2-methoxyphenylsilmethylene-CO-1,1-dimethyl-2-hydroxylsilane) pe Equipped with a stirrer, a reflux tube, a dropping funnel and a thermometer. 21
In a three-necked flask, add 31.0 g of magnesium powder (
1,28 mol), dimethyldichlorosilane 12
9 g (la+o1) and diethyl ether 500
1m! ! Put in. After cooling the flask to below 10°C, add 100 g of p-methoxybenzyl chloride from the dropping funnel.
(0,639 mol) and diethyl ether 250 m
7! dropwise over 4 hours. After aging for a further 1 hour at room temperature, excess magnesium and magnesium chloride are removed by suction filtration. The filtrate was distilled to obtain 87.8 g (0,409 mo j!) of the desired product. The yield was 64.0%, and the boiling point was 80°C/L+nHg.

In addition, the NMR spectrum (60MNz, C1a, CH
zClz δ5.33) is 60.46 (6H,S
), 2.40 (2H,S), 3.83 (3H
, S) , 6.82 (2H, d, J = 9.0
Hz), 7.08 (2H, d, J=9.0 Hz
), and the IR spectrum (νcm-”) is 2970
．． 1620.1520.1475゜1310, 1260
．． 1195.1090.1055.855, 825.
It was 780.

Synthesis of dimethylsilylmethane (d l ) Me
H In a 500 ml three-necked flask equipped with a stirrer and reflux tube, add chlorodimethyl-p-methoxyhensylsilane 4
3.2 g (0,200 mol) and carbon tetrachloride 2
00m Enter R. While heating and stirring carbon tetrachloride,
N~dibrosuccinimide 35.6 g (0,200
Gradually add mo R). After aging for 1 hour, the succinimide was removed by suction filtration, and the filtrate was distilled to obtain 31.7 g (0,108 mo j!) of the target product.
)Obtained. The yield was 54.0%. And the boiling point is
113-117'C/2.5mmHg, melting point was 30°C or less. In addition, NMR spectra (60MNz,
CCl4. TMS) is δ0.50 (3H.

S), 0.60 (3H,S), 3.73 (3H
, S), 4.32 (l H, S), 6.73 (2
H, d, J = 9Hz), 7.19 (2H, d,
J=9Hz), and the IR spectrum (cm-')
is 1610.1510.1465.1305°126
0, 1185.1040.865, 845, 820
, 800.

1-(3) Synthesis of poly(1,l-dimethyl-2-methoxyphenylmethylene) Me H A 5001 Ill three-necked flask equipped with a Hersch-Herck stirrer, reflux tube, and dropping funnel is purged with nitrogen.

7.6 g of sodium (0.33 g a
tom) and) /l/I 7120+114! It was placed,
Fine particles of sodium are obtained by heating and stirring. While stirring the toluene under reflux, add 44.1 g of bromo-p-methoxyphenylchlorodimethylsilylmethane (0,
15 mo and 30 ml of toluene! Add the mixture dropwise over 1 hour. After subsequent aging for 1 hour, the reaction mixture is poured into methanol to remove excess sodium and precipitate the polymer. After filtration, the polymer dissolved in tetrahydrofuran is dropped into water to remove sodium salts. The filtered polymer was washed with methanol and dried under reduced pressure to obtain the target product log. Yield is 37%
Met. The softening point was 121 to 125°C, and the weight average molecular weight was 3,400. Also, NMR spectrum/L
/ (60MH2, CbDb.

CH2 (1!2, 65.33) is δ1.27 (6H,
br, s).

4.43 (3H, br, s), 7.4-8.7
(4H, br, s).

Methine protons are difficult to identify, and the IR spectrum (el11-') is 2960.2850.1610.
1510. 1470°13B5.1300.1260
．． 1100.1045.860, 790 te was there.

Furthermore, in the Grignard reaction, the weight average molecular weight is 1,0
It was about 00.

Me HMe H 1 1 1 Me OH Into a 25 ml eggplant-shaped flask equipped with a reflux tube, poly(1,1-dimethyl-2-p-
methoxyphenylsilmethylene) 0.50 g (2.8 mmol in monomer unit) and chloroform 1.5
mj! and trimethylsilyl iodide 0.88 g
(4.4 mmo j!) and stir with a magnetic rod. After reacting for 4 hours, add 4 ml of methanol! and stir for 3 hours.

At room temperature, low-boiling substances are distilled off under reduced pressure, and the residual aroma is extracted with ether. The ether solution is washed with an aqueous sodium bisulfite solution, an aqueous sodium bicarbonate solution, and brine, and the ether is distilled off under reduced pressure. The obtained polymer was reprecipitated with tetrahydrofuran/water and dried under reduced pressure to obtain the desired product at a concentration of 0.23
I got g. Weight average molecular weight is 1,800, OH content is 10
0%, and the softening point was 107-113°C. Also NMR
Spectrum (60MHz.

DMSO-ds, 65.68), δ-0,79~
0.51 (6H.

br, s), 6.15-7.35 (4H, br,
s), methine proton, and hydroxy proton are difficult to confirm, and the IR spectrum (effl-') is 338
0.2980.1510°1270, 1100.104
They were 0.860 and 810.

Note that the OH content can be controlled by the amount of trimethylsilyl iodide or reaction time. For example, when a methoxy group is reacted with 1.3 equivalents of trimethylsilyl iodide for a reaction time of 4 hours, 90% of the methoxy group is converted to a hydroxyl group. Also, at 0.80 equivalent, 70%, 0
．． The conversion was 55% at 65 equivalents and 40% at 0.50 equivalents. The value of the OH content was determined by conducting the reaction in deuterated chloroform and tracking the process of converting a methoxy group into a trimethylsiloxy group using an NMR spectrum.

Regarding the solubility of 1-(51-soluble poly(1,1-dimethyl-2-p-methoxyphenylsylmethylene-co-1,1-dimethyl-2-p-hydroxyphenylsylmethylene)), typical general-purpose organic As a result of examining the polymer of the present invention with an OH content of 40% or more, methanol, tetrahydrofuran,
It dissolved in N, N-dimethylacetamide, 2-methylcyclohexanone, isoamyl acetate, methyl cellosolve, and dimethyl sulfoxide, but it dissolved in toluene, hexane,
It was insoluble in carbon tetrachloride. On the other hand, in the aqueous solution, it was dissolved in an aqueous tetramethylammonium hydroxide solution.

1-(6) Oxygen plasma resistant poly(1,1-dimethyl-2-p-methoxyphenylsylmethylene-co-1,1-dimethyl-2-p-hydroxyphenylsylmethylene) 10% by weight 2-methylcyclohexanone ) was applied onto a silicon substrate by a spin-neating method and baked at 100° C. for 30 minutes to form a 0.2 μm Vg− polymer coating. Next, oxygen plasma (conditions: oxygen pressure Q, 5 to
Although the polymer was exposed to a vacuum of 10-'torr (RF2O3W) for 10 minutes, the polymer did not permeate the membrane at all.

[Effects of the Invention] As described above, the polymer of the present invention is soluble in general-purpose organic solvents, so it can be formed into a film, and it is also soluble in an alkaline aqueous solution, so it can be used in compositions with O-quinonediazides. The composition becomes an alkali-developed positive-working photoresist, and the composition with bisazides becomes an alkali-developed negative-working photoresist. Furthermore, the composition with poly(olefin sulfone) can also be used as an alkali-developed positive-working electron beam resist. On the other hand, since the polymers of the present invention have excellent oxygen plasma resistance, these resists can be used as upper layer resists in a two-layer resist method. In other words, the polymer of the present invention is extremely useful as a functional polymer material such as a light- and radiation-sensitive material.

Claims (1)

[Scope of Claims] 1. An alkali-soluble silmethylene polymer characterized by comprising a structural unit represented by the following general formula (1). General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (However, in general formula (1), R_1, R_2, and R_
3 represents a monovalent organic group, R_4 represents an alkyl group, and OH
The number l of groups and OR_4 groups is 1 or 2, m and n are positive integers at any position on the benzene ring, and m+n is 2 to 2.
200, n/(m+n) is 0.4 or more. )2, in claim 1, R_1 in general formula (1)
, R_2 and R_4 are methyl groups, R_3 is hydrogen, l is 1, and OH group and OR_4 group are p-
An alkali-soluble silmethylene polymer characterized in that the position is