JPH0521228B2 - - Google Patents

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-sensitive material. More specifically, it relates to an alkali-soluble siloxane polymer in which units represented by general formula (1) account for 40% or more of the siloxane skeleton. [Background of the Invention] In the production of electronic components such as semiconductor elements and integrated circuits, microfabrication is performed using etching techniques that utilize light and radiation. Most of the resist materials used at this time are alkali-developable resists containing an alkali-soluble polymer such as phenolic resin or polyvinylphenol as a basic polymer because of their excellent resolution. For example, a composition of phenol novolak resin and o-quinone diazides is a positive photoresist;
It is known that compositions of polyvinylphenol and bisazides produce negative photoresists. On the other hand, as the wiring patterns of semiconductor devices and the like become finer, dry etching is being adopted instead of wet etching for etching the exposed base after patterning the resist layer. Therefore, the resist material is required to be resistant 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, and there has been a strong desire to improve their properties. In addition, as a literature regarding alkaline phenomenon type resist, JC Streater (JC
"Kodak Microelectronics Seminar Proceedings" (Kodak Strieter)
Microelectronics Seminar Proceedings) 116,
(1976), etc. [Object of the Invention] An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide an alkali-soluble siloxane polymer having excellent oxygen plasma resistance. [Summary of the Invention] Siloxane polymers are examples of polymers with excellent oxygen plasma resistance. Further, as alkali-soluble polymers, polymers having phenolic hydroxyl groups such as phenolic resins and polyvinylphenols are known. Therefore, the present inventor synthesized various polymers having a siloxane skeleton in the main chain and a phenolic hydroxyl group in the side chain, and as a result, the unit represented by the following general formula (1) was synthesized.
It has been found that a siloxane polymer containing 40% or more in the siloxane skeleton is a polymer that satisfies the above objectives. Here, in the above general formula (1), R ₁ is hydrogen or a monovalent organic group other than an aromatic group, and the latter is, for example, an alkyl group (for example, an alkyl group having 1 to 5 carbon atoms), a vinyl group, or Among these substituents, -CH ₃ , -C ₂ H ₅ , -C ₃ H ₇ are preferred, and R ₂ and R ₃ are H, Cl or a monovalent organic group, and this organic group is, for example, an alkyl group (e.g.
C1-C5 alkyl groups, etc.), vinyl groups, aromatic groups (e.g.

【formula】

[Embodiments of the invention]

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples. Examples For poly(methyl-p-methoxybenzylsiloxane-co-methyl p-hydroxybenzylsiloxane). (a) Synthesis of methyldichloro-p-methoxybenzylsilane In a three-necked flask equipped with a stirrer, reflux tube, dropping funnel, and thermometer, 23.3 g (1.00 mol) of magnesium powder and methyltrichlorosilane were placed.
82.6g (0.640mol) and diethyl ether 200
I put ml. After activating the magnesium with iodine and dibromoethane, the flask was cooled from 10°C to 0°C. From the dropping funnel, a mixture of 50.0 g (0.319 mol) of p-methoxybenzyl chloride and 300 ml of diethyl ether was added dropwise with stirring at a temperature between 10° C. and 0° C. over 4 hours. After aging for an additional hour at room temperature, excess magnesium and magnesium chloride were removed by suction filtration. Distill the liquid to obtain 48.8g of the target product.
(0.208 mol) was obtained. The yield was 65%. The physical properties of the target product were as follows. Boiling point: 86-88℃/2mmHg NMR: (60MHz, CCl ₄ , CH ₂ Cl ₂ δ5.33) δ0.79
(3H, S), δ2.68 (2H, S), δ3.84 (3H,
S), δ6.80 (2H, d, J=9Hz), δ7.18 (2H,
d, J=9Hz), IR (νcm ^-1 ) 1620, 1520, 1480, 1310,
1260, 1190, 1100, 1050, 850, 810, 755. (b) Synthesis of methyl-p-methoxybenzylsiloxane trimer 200 ml of water was placed in a three-necked flask equipped with a stirrer, a reflux tube, and a dropping funnel. While stirring, a mixture of 85.6 g (0.364 mol) of methyldichloro-p-methoxybenzylsilane and 200 ml of ethyl ether was added dropwise from the dropping funnel over 4 hours while maintaining the temperature at room temperature. After further aging for 1 hour, organic substances were extracted with diethyl ether and washed with water until the washing water became neutral. The diethyl ether solution was dried over sodium sulfate, diethyl ether was distilled off, and calcium hydride was added and distilled to obtain 20.3 g (37.5 mmol) of the target product. The yield was 31%. The physical properties of the target product were as follows. Boiling point: 241℃/0.8mmHg ~ 253℃/0.3mmHg NMR: (60MHz, _{CCl4 , CH2Cl2δ5.33} )δ−
0.02, δ0.03, δ0.16 (9H, SX3), δ1.96, 2.07
(6H, SX2), δ3.79 (9H, S), δ6.74 (CH,
d, J = 9Hz), δ6.98 (6H, d, J = 9Hz), IR (νcm ^-1 ) 1620, 1520, 1470, 1305,
1260, 1220, 1185, 1090, 1030, 840, 815,
770. (c) Synthesis of poly(methyl-p-methoxybenzylsiloxane) In a 100ml eggplant-shaped flask containing a magnetic rod, 9.0g (17mmol) of methyl-p-methoxybenzylsiloxane trimer and 45mg (0.5mg) of tetramethylammonium hydroxide were added. % by weight) and capped. Place the flask in an oil bath kept at 80°C.
Stir with a magnet. The weight average molecular weight decreased to 5,000 in 4 minutes after the reaction started, to 10,000 in 10 minutes, and to 10,000 in 20 minutes.
It rose to 14,000, then 16,000 in 30 minutes, and 19,000 in 60 minutes. Therefore, after reacting for a suitable period of time, the flask is removed from the oil bath and cooled with water to obtain the desired product with the desired weight average molecular weight. The contents in the flask were used as they were in the next reaction. The physical properties of the target product were as follows. NMR: (60MHz, _CCl4 , _CH2Cl2 , _δ5.33 )
δ0.00 (3H, br.S), δ1.94 (2H, br.S) δ3.71,
δ3.80 (3H, SX2), δ6.82 (4H, br.S), IR (νcm ^-1 ) 2975, 2850, 1620, 1520,
1475, 1305, 1260, 1225, 1190, 1090,
1040, 845, 810, 775, 755. (d) Synthesis of poly(methyl-p-methoxybenzylsiloxane-co-methyl-p-hydroxybenzylsiloxane) A reflux tube was attached to the flask containing poly(methyl-p-methoxybenzylsiloxane), and the system was flushed with nitrogen. Replaced with. 30 ml of chloroform was placed in a flask to make a uniform solution of the polymer, and a certain amount of trimethylsilyl iodide was added.
Stir at room temperature for 3 hours, add 20ml of methanol,
The mixture was further stirred for 2 hours. After the reaction was completed, low-boiling substances were distilled off at room temperature under reduced pressure, and the mixture was extracted with tetrahydrofuran and diethyl ether. The extract was washed with an aqueous sodium bisulfite solution, an aqueous sodium bicarbonate solution, and brine, and the solvent was distilled off under reduced pressure with heating to obtain the desired product. for methoxy group
By reacting with 1.5 equivalents of trimethylsilyl iodo, 100% of the methoxy groups were converted to hydroxyl groups. Also, 90% at 1.3 equivalents and 90% at 0.76 equivalents
The conversion was 71%, 58% with 0.65 equivalents, and 41% with 0.47 equivalents. The physical properties of the target product were as follows. Melting point: (weight average molecular weight 10000, 80% OH form) 53
~68℃ NMR: (60MHz, _{CD3CSCD3 , CH2Cl2δ5.68} ) _,
δ−0.07 (br.S, CH ₃ ), δ1.85 (br.S, −CH ₂
−), δ4.00 (br.S, −OCH ₃ ), δ6.61 (br.S, ring proton), δ8.81 (br.S, −OH) IR (νcm ^-1 ) 3320, 1620, 1510 , 1450,
1270, 1240, 1180, 1070, 840, 800. (e) Solubility The solubility of poly(methyl-p-methoxybenzylsiloxane-co-methyl-p-hydroxybenzylsiloxane) was investigated using typical general-purpose organic solvents. As a result, methanol, tetrahydrofuran, N,N-dimethylacetamide,
It was soluble in 2-methylcyclohexanone, isoamyl acetate, methyl cellosolve, and dimethyl sulfoxide, but insoluble in toluene, hexane, and carbon tetrachloride. On the other hand, as an aqueous solution, it was dissolved in a tetramethylammonium hydroxide aqueous solution and a potassium hydroxide aqueous solution. (f) Oxygen plasma resistance A 5% by weight solution of poly(methyl-p-methoxybenzylsiloxane-co-methyl-p-hydroxybenzylsiloxane) in 2-methylcyclohexanone was coated onto a silicon substrate with a spinner to a thickness of 0.2 μm. The above polymer coating was formed.
This coating film was baked at 90°C for 30 minutes. Next, oxygen plasma (conditions: oxygen pressure 0.5 torr, degree of vacuum
10 ^-4 torr, RF300W) for 10 minutes, but the film did not deteriorate at all. [Effects of the Invention] As described above, the siloxane polymer of the present invention is soluble in general-purpose organic solvents, so it can be formed into a film.
Furthermore, since it is soluble in an alkaline aqueous solution, it can be combined with o-quinone diazides to produce an alkaline phenomenon positive photoresist, and in combination with bisazides to produce an alkaline phenomenon negative photoresist. Furthermore, the siloxane polymer of the present invention itself can be used as an alkali-developed negative-working electron beam resist, and the combination with poly(olefin sulfone) can be used as an alkali-developed positive-working electron beam resist.

Claims (1)

[Scope of Claims] 1. An alkali-soluble siloxane polymer in which units represented by general formula (1) account for 40% or more of the siloxane skeleton. (However, in general formula (1), R ₁ is H or a monovalent organic group other than an aromatic group, R ₂ and R ₃ are H, Cl, or a monovalent organic group, l is an integer of 1 to 6, k is 1 or 2.) 2 In claim 1, the general formula (1)
R ₁ is a methyl group, R ₂ and R ₃ are hydrogen, l=1, k=
1. An alkali-soluble siloxane polymer in which an OH group is bonded to the p-position of the benzene ring.