JPH0582850B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] 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 ladder silicone represented by general formula (1). [Prior technology] Microfabrication technology by etching using light and radiation is used to manufacture electronic components such as semiconductor elements and integrated circuits, and currently resist materials such as phenol resin and Alkaline-developable resist materials containing an alkali-soluble polymer such as polyvinylphenol as a basic polymer are the mainstream. For example, a composition of novolak resin and 1,2-naphthoquinone diazides is a positive photoresist, and a composition of polyvinylphenol and bisazides is a negative photoresist. Furthermore, it is widely known that a composition of novolac resin and polyolefin sulfone is a radiation-sensitive positive resist. On the other hand, with the miniaturization of wiring in semiconductor devices and the like, dry etching is increasingly being adopted in place 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. Conventional alkali-developable resist materials exhibit strong resistance to halogen-based plasma used when the underlying material is a metal or metal oxide film (e.g. aluminum, silicon, silicon oxide film, etc.), but when the underlying material is an organic material (e.g. The resistance to oxygen plasma used in the case of the lower layer planarizing film in the layered resist method, the interlayer insulating film such as polyimide, etc.) is not sufficient, and there has been a strong desire to improve its properties. In addition, as a literature on alkali-developable resists, JC
Written by Strieter: Kodak Microelectronics Seminar Proceedings
Microelectronics Seminar Proceeding) 116
(1976), etc. [Problems to be Solved by the Invention] The purpose of the present invention is to provide an alkali-soluble polymer with excellent oxygen plasma resistance, which can be used as a substitute for the basic polymer of the conventional alkaline developable resist, which has low oxygen plasma resistance. be. [Means for Solving the Problems] Organosilicon polymers are well known as polymers with excellent oxygen plasma resistance. this is,
This is because the organosilicon polymer efficiently turns into a silicon oxide film by oxygen plasma, and this silicon oxide film acts as an oxygen plasma resistant film. on the other hand,
As alkali-soluble polymers, polymers having phenolic hydroxyl groups such as novolac resins and polyvinylphenol are known. Therefore, in order to achieve the above objective, we synthesized various polymers with a ladder silicone skeleton whose main chain is closest to the structure of silicon oxide and a phenolic hydroxyl group in the side chain. I found out that ladder silicone is good. (R ₁ −SiO _3/2 ) _o (R ₂ −SiO _3/2 ) _n (R ₃ −SiO _3/2 )
_l (R ₄ −SiO _3/2 ) _p (R ₅ −SiO _3/2 ) _p (R ₆ −SiO _3/2 ) _q …(1
) However, R ₁ and R ₂ in general formula (1) are organic groups having a phenolic hydroxyl group, and R ₃ , R ₄ , R ₅ and R ₆ are organic groups not containing a phenolic hydroxyl group. Also,
n, m are positive integers not including zero, l, o, p,
q is a positive integer including zero, (n+m)/(n+
m+l+o+p+q)>0.4 must be satisfied. Here, R ₁ and R ₂ are specifically, for example,

[ka]

[ka]

[ka]

[Effect]

The polymer of the present invention has high oxygen plasma resistance because the polymer skeleton is a ladder silicone skeleton that is closest to the structure of a silicon oxide film, and also because it has an organic group having a phenolic hydroxyl group in the side chain. It is thought that it has become alkali soluble. [Example] Hereinafter, the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples. Example 1 Poly(p-hydroxybenzylsilsesquioxane-co-p-hydroxyphenylethylsilsesquioxane-co-p-methoxybenzylsilsesquioxane-
1.1 Synthesis of p-methoxybenzyltrichlorosilane Stirrer A 5-four neck flask equipped with a condenser, a dropping funnel, and a hydrochloric acid trap was purged with nitrogen. In a flask, 79g (0.80mol) of cuprous chloride
and tri-n-propylamine 126/g
(8.80 mol), and a mixture of 1256 g (8.02 mol) of p-methoxybenzyl chloride and 1184 g (8.74 mol) of trichlorosilane was added dropwise over 5 hours with stirring under nitrogen pressure. After aging until the flask temperature returned to room temperature, hexane 1
to precipitate the salt. After filtering the salt, 1182g of the target product was distilled under reduced pressure.
(4.62 mol) was obtained. Yield 57.7%bp92℃/4mm
HgNMR (60MHz, _CCl4 , _CH2Cl2 ) δ2.93 ( _2H ,
s), δ3.83 (3H, s) δ6.86 (2H, d, J) = 9
Hz), δ7.15 (2H, d, J = 9Hz). 1.2 Synthesis of p-methoxyphenylethyltrichlorosilane 36.7 (0.274 mol) of p-methoxystyrene and 37.1 g (0.274 mol) of trichlorosilane are placed in a Pyrex tube. Next, 99.4 mg of chloroplatinic acid, tri-
A few drops of suspension consisting of 81.0 mg of n-butylamine and 0.1888 g of p-methoxystyrene.
Add to Pyrex tube and seal. Seal the tube at 80℃~100℃
After reacting in an oil bath at ℃, open the sealed tube and distill the contents to obtain the desired product at 40.0℃.
g (0.148 mol) was obtained. Yield 54% bp84-85℃/
2mmHgNMR (60MHz, CCl ₄ , TMS) δ1.48~
1.76 (2H, m), δ2.62~2.88 (2H, m), δ3.60
(3H, s), δ6.61 (2H, d, J=8.5Hz) δ6.92
(2H, d, J = 8.5Hz) 1.3 Synthesis of poly(p-methoxybenzylsilsesquioxane-co-pmethoxyphenylethylsilsesquioxane) Equipped with a stirrer, cooling tube, dropping funnel, and hydrochloric acid trap. Pour 80ml of water into a 200ml three-necked flask. 10.8g p-methoxyphenylethyltrichlorosilane (40ml) dissolved in 20ml toluene
10.2 g (40 mmol) of p-methoxybenzyltrichlorosilane were added dropwise over 15 minutes with stirring, and then aged for 1 hour. Transfer the mixture to a separatory funnel and separate the toluene layer. After removing toluene and water by distillation, 0.21 g of a 10 wt % methanol solution of potassium hydroxide is added to the above hydrolyzed product and heated at 200° C. for 2 hours.
Dissolve the reaction mixture in tetrahydrofuran,
After removing insoluble matter by filtration, 5.3 g of the target product was obtained by distilling off tetrahydrofuran.
Number average molecular weight 1000-300000NMR (60MHz,
DMSO- _d6 , TMS) δ0.72 (2H, br, s) δ1.97
(2H, br, s), δ2.37 (2H, br, s), δ3.58
(6H, br, s), δ6.67 (8H, br, s). The ratio of p-methoxyphenylethyl groups to p-methoxybenzyl groups was about 50:50. 1.4 Synthesis of poly(p-hydroxybenzylsilsesquioxane-co-p-hydroxyphenylethylsilsesquioxane) A 100 ml three-necked flask equipped with a stirrer, condenser, dropping funnel, and hydrochloric acid trap was purged with nitrogen. 5.0 g of poly(p-methoxybenzylsilsesquioxane-co-p-methoxyphenylethylsilsesquioxane) described in Section 1.3 was dissolved in 15 ml of acetonitrile and put into a flask, and then 13.0 g of sodium iodide was added. Add. While heating and refluxing under nitrogen pressure, 9.4 g of trimethylchlorosilane was added dropwise over 15 minutes. After aging for 50 hours at reflux under nitrogen pressure, 20 ml of water are added dropwise, then acetonitrile is added and the reaction mixture is heated at reflux for a further 6 hours. After the reaction is completed, the reaction mixture is transferred to a separating funnel and the acetonitrile layer is separated. The acetonitrile layer is then washed with an aqueous sodium bisulfite solution. The acetonitrile layer was dropped into a large amount of water, the polymer was filtered, and then heated under vacuum to obtain 3.9 g of the desired product.
NMR (60MHz, DMSO−d ₆ , TMS) δ0.78
(2H, br, s) δ1.90 (2H, br, s), δ2.45
(2H, br, s), δ6.60 (8H, br, s), δ8.97
(2H, br, s) The number average molecular weight and the ratio of p-hydroxybenzyl groups and p-hydroxyphenylethyl groups are
Same as the precursor described in Section 1.3. In addition, copolymers with different ratios of p-hydroxybenzyl groups and p-hydroquine phenylethyl groups can be made by changing the ratio of p-methoxybenzyltrichlorosilane and p-methoxyphenylethyltrichlorosilane during hydrolysis I could change it at will. 1.5 Poly(p-hydroxybenzylsilsesquioxane-co-p-hydroxyphenylethylsilsesquioxane-co-p-methoxybenzylsilsesquioxane-
Synthesis of co-p-methoxyphenylethylsilsesquioxane-co-p-trimethylsiloxybenzylsilsesquioxane-co-p-trimethylsiloxyphenylethylsilsesquioxane) In the synthesis method of benzylsilsesquioxane (co-p-hydroxyphenylethylsilsesquioxane), reducing the amount of reaction reagents (trimethylchlorosilane and sodium iodide) that convert methoxy groups to trimethylsiloxy groups or aging By shortening the time, methoxy groups can be left in any proportion. In addition, in the process of converting trimethylsiloxy groups to hydroxyl groups by hydrolysis, if the aging time is shortened,
Up to about 15% of the trimethylsiloxy groups can be left intact. However, it is not possible to specify whether the hydroxyl group, methoxy group, or trimethylsiloxy group is attached to the benzyl group or the phenylethyl group. Table 1 shows the hydroxyl group content, methoxy group content, trimethylsiloxy group content, and their respective aging time dependencies when a polymer similar to the polymer described in Section 1.3 was used and reacted with the amount of reagent described in Section 1.4.

〔Effect of the invention〕

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 alkaline aqueous solutions, so it can be used as a base polymer for various photosensitive dissolution inhibitors or photosensitive dissolution inhibitors. A composition with a radioactive dissolution inhibitor can be used as a resist material for light or radiation corresponding thereto. On the other hand, since the present polymer has excellent oxygen plasma resistance, these resists can be used as an upper layer resist, etc. in a two-layer resist method. As described above, 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 ladder silicone polymer represented by the following general formula (1) and having a molecular weight of 1,000 to 300,000. (R ₁ −SiO _3/2 ) _o (R ₂ −SiO _3/2 ) _n (R ₃ −SiO _3/2 )
_l (R ₄ −SiO _3/2 ) _p (R ₅ −SiO _3/2 ) _p (R ₆ −SiO _3/2 ) _q …(1
) (However, R ₁ in general formula (1) is a p-hydroxybenzyl group, R ₂ is a p-hydroxyphenylethyl group,
R ₃ is a p-methoxybenzyl group, R ₄ is a p-methoxyphenylethyl group, R ₅ is a p-trimethylsiloxybenzyl group, and R ₆ is a p-trimethylsiloxyphenylethyl group. Also, n and m are positive integers that do not include zero, and l, o, p, and q are positive integers that include zero, and (n+m)/(n+m+l+o+p+q)>0.4
must be met. )