JPH11263845A - Polysilane and method for synthesizing polysilane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polysilane which is soluble in an organic solvent, can be easily formed into a thin film, and can form a film having high mechanical strength. SOLUTION: This polysilane is soluble in an organic solvent, has a glass transition temperature of -40 ° C or higher, and contains a copolymer containing a repeating unit represented by the general formula (1). Embedded image (In the above general formula (1), R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms, and a is 0.1 or more and 0.1 or more.
9 or less. )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilane and a method for synthesizing the polysilane.
Anti-reflection film, precursor of insulating material, photoconductor, luminescent material,
The present invention relates to a polysilane useful as a charge transporting material or a nonlinear optical material and a method for synthesizing the polysilane.

[0002]

2. Description of the Related Art Various methods have been reported for the synthesis of poly (alkylhydrosilane) s.
Most of them relate to the synthesis of poly (methylhydrosilane). According to a general synthesis method of polycondensation of dichlorosilane with metallic sodium, only an oil-like polysilane having an average molecular weight of about 1000 is obtained (Mauricio F. Gozzi et al., Macr.
omolecules, 1995, 28, 7235).

[0003] Such low molecular weight polysilanes have many practical problems such as low mechanical strength when formed into a film.
Although poly (alkylhydrosilane) s have been synthesized by other methods, each method has various disadvantages. For example, a method of synthesizing poly (alkylhydrosilane) by plasma CVD using alkylsilane (RSiH ₃ ) has been reported (Timoth).
y W. Weidman et al., Appl. Phys. Le
tt. 62 (4), 372, 1993). However, in this method, there is a problem in safety because an alkylsilane monomer, which easily ignites or explodes in air, is used. Further, there is a problem that the cost is increased because CVD is used.

As a method for synthesizing polysilane, there is a method for obtaining polysilane by dehydrocondensing monosubstituted silane (RSiH ₃ ) with a titanocene or zirconesene catalyst (JF Harrod, ACS, Polym. P).
repr. , 28, 403 (1987)). When synthesized by this method, the degree of polymerization of the resulting polysilane is increased to about 20, and there is a disadvantage that some metal catalyst remains in the purified polymer and cannot be removed.

On the other hand, as a synthesis method of polysilane, a method of polycondensing dichlorosilane with sodium metal has been mainly performed as the most general synthesis method. However, this polycondensation reaction has a problem that it is difficult to control and the yield of high molecular weight polysilane obtained is poor. To solve this problem, a method of adding crown ether has been proposed (DJ Worsfol).
d et al., Macromolecules, 22, 2213.
(1989)). Although the addition of crown ether increases the yield, it has the drawback that the molecular weight distribution changes significantly and the average molecular weight is greatly reduced.
Further, it has been reported that a high-molecular-weight polysilane can be obtained in a high yield by performing the above-mentioned polycondensation reaction in the presence of a copper compound (Japanese Patent Application Laid-Open No. Hei 4-185842). However, in that example, it is limited to only a polycondensation reaction using a general monomer such as phenylmethyldichlorosilane,
The effect of polysilane synthesis from alkylhydrodichlorosilanes (RHSiCl) having highly reactive Si-H bonds has not been confirmed.

[0006]

As described above, at present, polysilane having a high molecular weight and a small amount of a residual metal catalyst, which can be suitably used for an antireflection film or the like, has not yet been obtained. . Furthermore, a method for safely and easily synthesizing such a high-molecular-weight polysilane in a high yield has not yet been found.

Accordingly, an object of the present invention is to provide a polysilane which is soluble in an organic solvent, can be easily formed into a thin film, and can form a film having high mechanical strength.

Another object of the present invention is to provide a method capable of safely and easily synthesizing the above-mentioned polysilane in a high yield.

[0009]

In order to solve the above-mentioned problems, the present invention relates to a repeating unit which is soluble in an organic solvent, has a glass transition temperature of -40 ° C. or higher, and is represented by the general formula (1). A polysilane containing a copolymer containing

[0010]

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(In the above general formula (1), R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms, and a is
It is 0.1 or more and 0.9 or less. The present invention also provides a method for synthesizing a polysilane represented by the following general formula (1) or the following general formula (3),

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(In the above formula, R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms, a is 0.1 or more and 0.9 or less. Even if R ¹ and R ² are the same, They may be different, each being a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group or an aromatic hydrocarbon group.) A copper compound, an ether compound, and an alkali metal are added to a solvent, and the mixture is heated to disperse the alkali metal. Obtaining a product, dropping a halosilane compound dissolved in a solvent into the dispersion to obtain a reaction product, and adding trimethylsilane dissolved in a solvent to the reaction product to further react. And a synthesis method comprising:

Hereinafter, the present invention will be described in detail.

The polysilane of the present invention has the general formula (1)
Is a copolymer having a repeating unit represented by the following formula: In the general formula (1), R is a substituted or unsubstituted aliphatic hydrocarbon having 6 or less carbon atoms. Examples of the aliphatic hydrocarbon that can be introduced as R include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclohexyl, 3,3, Examples thereof include a 3-trifluoropropyl group and a 3-methoxypropyl group, but are not particularly limited.

A in the general formula (1) is 0.1 or more and 0.9 or less. When a is less than 0.1, the polymer is not only liquid but also easily oxidized, while if a exceeds 0.9, it may be insoluble. Note that a is
More preferably, it is 0.4 to 0.7.

Here, specific examples of the repeating unit represented by the general formula (1) are shown below.

[0017]

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It is desired that the repeating unit represented by the general formula (1) be contained in the copolymer of the present invention in an amount of about 0.1 to 0.9 in terms of mole fraction with respect to polysilane of 1. . If it is less than 0.1, the effect of the Si-H bond is hardly obtained, while if it exceeds 0.9, it may be liable to be oxidized.

In the present invention, the copolymer containing a repeating unit represented by the above general formula (1) has a molecular weight of 500
~ 100,000, preferably 1000 ~ 1
More preferably, it is 0.000. If it is less than 500, the polymer becomes liquid, while if it exceeds 100,000, it may be insoluble.

Examples of the copolymer component to be copolymerized with the repeating unit represented by the general formula (1) include those represented by the following chemical formula.

[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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Among these repeating units, a repeating unit represented by the following general formula (2) is particularly preferable.
By including this repeating unit, it is possible to achieve both the stability against oxidation and the effect of the Si—H bond (crosslinking property, reactivity).

[0037]

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(In the above general formula (2), R ⁰ is a group having 2 carbon atoms.
It represents a substituted or unsubstituted aliphatic or aromatic hydrocarbon group having 0 or less, and Ar represents a substituted or unsubstituted aromatic hydrocarbon group having 20 or less carbon atoms. Here, R ⁰ is, for example, a methyl group, an ethyl group,
Examples include a propyl group, a hexyl group, a dodecyl group, and a cyclohexyl group. Examples of Ar include phenyl, methoxyphenyl, halogenated phenol, naphthyl, and anthranyl.

When such a repeating unit represented by the general formula (2) is contained, the effect is exhibited as long as its content is about 20 mol% in the copolymer of the present invention. However, if it is contained excessively, the Si content may be reduced, so that the ratio is desirably set to about 90 mol% or less in the copolymer.

The polysilane of the present invention, which is a copolymer having a repeating unit represented by the general formula (1) as described above, is soluble in an organic solvent and has a glass transition temperature of -40 ° C. or higher.

Incidentally, in the copolymer of the present invention, Si-
The H bond content is preferably 90% or less.
More preferably, 10% or more of the iH bonds are crosslinked. This is because if the content of the Si-H bond exceeds 90%, oxidation may occur.

The polysilane of the present invention may further contain about 0.01 to 20 parts by weight of an antioxidant based on 100 parts by weight of the polymer. By adding an antioxidant, it is possible to prevent oxidation in air and in baking.

The following chemical formula shows examples of antioxidants which can be used in the present invention.

[0044]

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[0045]

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The polysilane of the present invention may contain a crosslinking agent. As the crosslinking agent, an organic substance having a multiple bond can be used. The organic substance having a multiple bond is a compound having a double bond or a triple bond, more specifically, a compound having a vinyl group, an acrylic group, an aryl group, an imide group, an acetylenyl group, a derivative thereof, and the like. The organic group having such a multiple bond may be any of a monomer, an oligomer and a polymer.

The organic substance having such a multiple bond causes an addition reaction with the Si—H bond of the polysilane by heat or light to crosslink the polysilane. Note that the organic substance having a multiple bond may be self-polymerized. Specific examples of the organic substance having a multiple bond are shown below.

[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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As described above, when a compound having a multiple bond to polysilane is mixed, a radical generator or an acid generator may be added as a catalyst. These radical generators or acid generators play a role in assisting an addition reaction or self-polymerization of an organic substance having a multiple bond with Si—H.

Examples of the radical generator include azo compounds (for example, azobisisobutyronitrile), peroxides, alkylaryl ketones, silyl peroxides, and organic halides. The radical generator generates a radical by decomposing an O—O bond or a C—C bond in a molecule by light irradiation or heating. As the radical generator, for example, those listed below can be used.

[0060]

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When an oxide is used, the oxide is contained in a solution containing polysilane. The content of the oxide is 0.01 to 50 parts by weight, preferably 1 to 20 parts by weight based on 100 parts by weight of the polysilane.

Next, the method for synthesizing the polysilane of the present invention will be described in detail.

In the synthesis method of the present invention, a halosilane compound is used as a raw material, and a condensation polymerization reaction is carried out in a solvent using an alkali metal as a catalyst in the presence of a copper compound and an ether compound as co-catalysts. Alternatively, it can be synthesized by subjecting a polycondensation reaction in a solvent using an alkali metal as a catalyst in the presence of a copper compound and a tertiary amine compound.

Examples of the halosilane compound include a compound represented by the following general formula (4).

[0065]

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(In the above formula (4), R ¹ and R
² may be the same or different and each represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group or an aromatic hydrocarbon group. X is a halogen atom. In addition, among the halosilane compounds, a monomer obtained by bonding halosilane with an organic group can be used.

Examples of the aliphatic hydrocarbon group which can be introduced as R ¹ or R ^{2 in the} general formula (4) include, for example, methyl group, ethyl group, propyl group, butyl group, cyclohexyl group, dodecyl group and the substitution thereof. Body and the like.
Examples of the aromatic hydrocarbon group that can be introduced as R ¹ or R ² include phenyl, naphthyl, anthranyl, and derivatives thereof.

The halogen atom which can be introduced as X includes F, Cl, Br, I and the like, and Cl is particularly preferable from the viewpoint of easy handling.

Examples of halosilane compounds that can be used in the present invention are shown in the following chemical formula.

[0070]

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[0071]

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[0072]

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In particular, a compound represented by general formula (4) represented by the following general formula (5), that is, R in general formula (4)
^{When 1} is an aliphatic hydrocarbon group and R ² is a hydrogen atom, the polysilane represented by the general formula (1) can be synthesized.

[0074]

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In the above general formula (5), R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms.
Is F, Cl, Br, I.

The aliphatic substituent introduced as R includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclohexyl, 3,3 , 3-trifluoropropyl group and 3-methoxypropyl group, but are not particularly limited. The crosslinked portion in the repeating unit represented by the general formula (1) is
Si-H is partially reacted and varies depending on the reaction conditions, the type of monomer, and the like.

Here, specific examples of the compound represented by the general formula (5) are shown below.

[0078]

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[0079]

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In synthesizing a polysilane by the method of the present invention using the above-mentioned halosilane compound as a raw material, first, for example, a copper compound, an ether compound and an alkali metal are added in a predetermined amount to an organic solvent, and the mixture is stirred while stirring. Heat to about 120 ° C. to prepare an alkali metal dispersion.

The solvent used here includes one or more non-polar solvents, specifically, hexane, peptane,
Examples include, but are not limited to, octane, toluene, xylene, cyclohexane, cumene, ethylbenzene, and a mixed solvent thereof.

As the copper compound, for example, copper halide,
Examples include, but are not particularly limited to, copper acetate, copper sestilacetonate, and copper cyanide. The addition amount is 0.1 to 10 mol% based on the halosilane monomer.

Examples of the ether compound include crown ethers and derivatives thereof, ethylene glycol derivatives such as tetrahydrofuran and diglyme; dioxane;
Tetraoxane, cryptant and the like. For example, as crown ethers, 1,4-dioxane, 1,3,5-trioxane, 15-crown-
Examples thereof include 5,12-crown-4, 18-crown-6, and benzo-18-crown-6, but are not particularly limited. Examples of the crown ether derivative include crown ether analogous compounds, for example, N, N'-dimethylpiperazine, 4-methylmorpholine, N-methyl-1
-Aza-18-crown-6, N-methyl-1-aza-
15-crown-5, N, N'-cibenzyl-4,13
-Diaza-18-crown-6, 1,4,7,10,1
3,16-hexamethyl-1,4,7,10,13,1
6-hexaazacyclooctadecane, 4,7,13,1
6,21,24-hexaoxy-1,10-diazabicyclo [8,8,8] hexacosan, 1,4,7,10,
13,16-hexathiacyclooctadecane and the like are included, but not particularly limited. The amount of addition of the crown ether and the crown ether analog is 1 to 100 mol% based on the halosilane monomer.

Examples of the ethylene glycol derivative include dioxane, tetrahydrofuran, diglyme, ethylene glycol dimethyl ether and the like. The amount of the ethylene glycol derivative to be added is preferably about 0.1 to 100 mol% based on the halosilane monomer.

As the alkali metal, for example, sodium metal, Li, K and the like can be mentioned, but in consideration of easy handling, sodium metal is preferable. The addition amount is 0.9 to 2.0 mol based on the halosilane monomer.
Used at 1%.

On the other hand, a predetermined amount of a halosilane compound is dissolved in a solvent to prepare a solution. Examples of the solvent used here include the same solvents and mixed solvents as described above.

A solution containing a halosilane compound is dropped into the dispersion obtained as described above at such a rate that reflux continues, and the mixture is further reacted at a solvent reflux temperature for 30 minutes to 5 hours.

An end capping agent such as trichloromethylsilane dissolved in a solvent such as anhydrous toluene is added to the reaction solution thus obtained, the mixture is reacted for about 30 minutes to 2 hours, and then cooled to room temperature.

Next, twice the amount of toluene was added to the cooled reaction solution to precipitate NaCl, and this precipitate was subjected to pressure filtration under a nitrogen atmosphere, and the filtrate was concentrated.

After adding 10 times the volume of ethanol to toluene to precipitate the polymer, the obtained polymer is filtered and dissolved in toluene. This toluene solution is washed with ion-exchanged water, and then dried with a drying agent such as anhydrous magnesium sulfate.

Next, after removing the desiccant, the solid obtained by removing the solvent under reduced pressure is dissolved in toluene, and this toluene solution is dropped into ethanol or the like to precipitate a precipitate.

Finally, the precipitate is filtered and dried under vacuum to obtain a polysilane having a repeating unit represented by the above formula (1) or (3).

In addition, in the step of adding the halosilane in the method described above, when the copolymerized monomer is added at the same time,
A copolymer containing a repeating unit represented by the general formula (1) and a repeating unit represented by the general formula (2) can be synthesized.

A polysilane can be synthesized in the same manner as described above except that a tertiary amine compound is used instead of the ether compound. In this case, as the tertiary amine compound that can be used, for example, N, N, N ′, N′-tetramethylethylenediamine, N, N-dimethylaniline, N, N, N ′, N ′, N ″- Pentamethyldiethylenetriamine and the like are mentioned, and the amount of addition is preferably about 0.1 to 100 mol% based on the halosilane monomer.

Alternatively, a cross-linked polysilane can be obtained by copolymerizing a halosilane compound with a silane compound represented by the following general formula (6) or (7) in which three or more halogen atoms are substituted. A polymer can be easily synthesized.

[0096]

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(In the above formula, R ³ is a hydrogen atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, and X is a halogen atom.) Examples of the hydrocarbon group that can be introduced as R ³ include: ,
Examples include a methyl group, an ethyl group, a propyl group, a hexyl group, a cyclohexyl group, a phenyl group, a naphthyl group, an anthranyl group and a substituted product thereof, and examples of the halogen atom include F, Cl, Br, and I.

Specific examples of the compound represented by formula (6) or (7) are shown below.

[0099]

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Since the polysilane of the present invention has a glass transition temperature of −40 ° C. or higher, there is obtained an advantage that it does not flow even when spin-coated or the solvent is removed. Moreover,
Since it has excellent solubility in organic solvents such as aliphatic hydrocarbons, aromatic hydrocarbons, ethers, and halogen solvents, it can be easily formed by a coating method such as spin coating. Furthermore, since the polysilane of the present invention has a sufficient degree of crosslinking, a film obtained by forming such a polysilane has excellent mechanical strength. Further, the polysilane of the present invention is advantageous in that it absorbs ultraviolet rays having a wavelength of 280 nm or less at a high level and can prevent light reflection in lithography.

The polysilane of the present invention having the above-mentioned characteristics can be preferably used as an antireflection film material.

Here, referring to FIGS. 1A to 1D,
A process for processing a silicon-based insulating film using an antireflection film formed of the polysilane of the present invention will be described. In addition, Ta
Insulating film such as O ₂ , RuO ₂ , AlSi, AlSiC
Processing of a conductive film such as u, Ti salicide, Co salicide, or Cu can be performed in a similar process.

As shown in FIG. 1A, a silicon substrate 1
On the substrate 1, a silicon-based insulating film 12, a polysilane film 13, and a resist film 14 are formed. The thickness of the insulating film is 10 μm
The following is preferable, and 0.5 to 1 μm is more preferable. If the thickness of the insulating film exceeds 10 μm, the aspect ratio increases, and a microloading effect such as an etching stop occurs remarkably.

The thickness of the polysilane film is preferably about 20 to 500 nm. The thickness of the polysilane film 13 is determined so as to satisfy the following two conditions.

(1) The reflectance at the interface between the resist and the polysilane film is calculated in consideration of the multiple reflection of the exposure light, and the film thickness is set so as to minimize the reflectance. The polysilane film thickness dependence of the reflectance at the interface between the resist and the polysilane film is calculated using the complex refractive index of the resist, the polysilane film, and the insulating film at the exposure wavelength. The specific calculation method is described in PH Berning, Physics of Thin Film, Vol.
1, pp.69-121 (1963); AE Bell & FW Spong, IEEE
Journal of Quantum Electronics, Vol.QE-14, pp.487
−495 (1978); K. Ohta & H. Isida, Applied Optics,
Vol. 29, pp. 1952-1958 (1990).

(2) The film thickness is such that it can be etched using the resist pattern as a mask and the insulating film can be etched using the etched polysilane film as a mask.

The polysilane film is formed by applying a solution in which polysilane is dissolved in an organic solvent, and then baking to evaporate the solvent. The organic solvent used at this time may be a polar solvent or a non-polar solvent. Examples of the polar solvent include ether solvents (eg, diethyl ether, dibutyl ether, tetrahydrofuran, anisole), cellosolve solvents (eg, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate),
Ester solvents (eg, ethyl acetate, butyl acetate, isoamyl acetate) and the like. Examples of the non-polar solvent include toluene, xylene, hexane, octane, cumene, and solvent naphtha. In addition, as a solvent for the polysilane dendrimer, a halogen-based solvent (methylene chloride, chlorobenzene, chloroform, or the like) can be used. The polysilane of the present invention has excellent solubility in these solvents and can be easily formed into a film by a coating method such as spin coating. When used for forming an antireflection film, the weight average molecular weight Mw of the polysilane is 500 to 1
000000 is preferable, and 2000 to 100000 is more preferable. This is because if the Mw is less than 500, the film is dissolved in a solvent and applied to form a film, resulting in poor mechanical strength, and if the Mw exceeds 1,000,000, the solubility in the solvent is reduced. Polysilane may be used alone or 2
You may mix and use more than one kind.

The polysilane film may have, as necessary, an adhesion enhancer for improving the adhesion to the base; a dye absorbing ultraviolet light for preventing reflected light from the insulating film into the resist film; A polymer (for example, polysulfone or polybenzimidazole); a surfactant or the like for improving wettability with a base may be added. In this case, the amount of the additive is adjusted so that the silicon content in the polysilane film containing the additive formed through baking is in the range of 1 to 50% by weight. If the silicon content is less than 1% by weight, the exposure light cannot be sufficiently absorbed, and a sufficient etching rate ratio cannot be obtained when etching the polysilane film using the resist pattern as a mask. On the other hand, a film having a silicon content of more than 50% by weight has poor applicability and easily causes pinholes in the coating film.

The resist film is formed by applying a resist solution on the polysilane film and baking. The smaller the thickness of the resist film, the higher the exposure margin, focus margin, or resolution at the time of exposure. Therefore, the thickness of the resist film is preferably as thin as possible within a range where the polysilane film can be etched with good dimensional controllability, and is preferably 500 nm or less. The resist is not particularly limited as long as it is a composition that can be patterned by exposure to ultraviolet light, electron beam or the like. In addition, a positive or negative resist can be selected and used according to the purpose. As the positive resist, for example, a resist composed of naphthoquinonediazide and a novolak resin (IX-770, manufactured by Nippon Synthetic Rubber Co., Ltd.), t-BOC
Chemically amplified resist (APEX-E, manufactured by Shipley Co.) comprising a polyvinylphenol resin and an onium salt protected by the above method. Examples of the negative resist include a chemically amplified resist composed of polyvinyl phenol, a melamine resin and a photoacid generator (XP-89131, manufactured by Shipley), and a resist composed of polyvinyl phenol and a bisazide compound (RD-200D). And Hitachi Chemical Co., Ltd.). In order to prevent the dimensional controllability of the resist pattern from deteriorating due to standing waves generated in the resist film, add a dye such as coumarin or curcumin that absorbs ultraviolet light into the resist to reduce the transparency of the resist. Is also good.

In order to more reliably prevent exposure light reflection from the underlayer to the resist film and to form a good resist profile after development, a film of about 10 to 150 nm is formed between the polysilane film and the resist film. A thick thin film may be formed. As a material of a thin film formed for this purpose and a method of forming the thin film, the following can be mentioned. For example, a silicon nitride film, a silicon oxide film, a silicon oxynitride film, a silicon carbide film, or a carbon film is formed by a sputtering method or a CVD method. In addition, a solution in which a polymer such as polysulfone, polyamide, novolak resin, or polyhydroxystyrene is dissolved in an organic solvent such as ethyl lactate or cyclohexanone is spin-coated to form a film. In the latter case, a dye such as coumarin or curcumin may be added.

Further, an upper anti-reflection film is formed on the resist film to reduce the light reflection at the interface between the resist film and air, thereby suppressing the generation of standing waves in the resist film. Is also good. Examples of such an upper antireflection film include Aquatar manufactured by Hoechst.

Next, as shown in FIG. 1B, the resist is irradiated with ultraviolet light as exposure light through a mask having a desired pattern, and then developed to form a resist pattern. As a light source for irradiating ultraviolet light, a mercury lamp, XeF (wavelength = 351 nm), Xe
Cl (wavelength = 308 nm), KrF (wavelength = 248 n)
m), KrCl (wavelength = 222 nm), ArF (wavelength =
Excimer laser such as 193 nm) and F ₂ (wavelength = 151 nm). The polysilane of the present invention is Si-
Since it has Si and has a high absorptivity to ultraviolet rays having a wavelength of 150 to 360 nm, it can absorb exposure light and suppress reflected light into the resist film. As a result, no wavy shape due to the standing wave is observed in the developed resist profile.
Also, even if the resist film thickness and the insulating film thickness fluctuate,
Variations in the resist pattern dimensions can be suppressed.
As a developer for the resist, an aqueous solution of an organic alkali such as tetramethylammonium hydroxide, sodium hydroxide,
An inorganic alkali aqueous solution such as potassium hydroxide or an organic solvent such as xylene or acetone is used.

Next, as shown in FIG. 1C, the polysilane film (etching mask) is etched using the resist pattern as a mask. Examples of the etching method include reactive plasma etching, magnetron reactive plasma etching, electron beam plasma etching, TCP plasma etching, ICP plasma etching, and ECR plasma etching. CF ₄ , CF ₃ Cl, CF ₂ as source gas
Cl ₂ , CF ₃ Br, CCl ₄ , C ₂ F ₅ Cl ₂ , CF
₄ + H ₂ , (CF ₄ , C ₂ F ₆ , CHF ₃ , SiF ₄ ,
CF ₃ Br) + (Cl ₂ , Br ₂ ), Cl ₂ (+
H ₂ ), SiCl ₄ , Br ₂ , I ₂ , Cl ₂ + Ar, S
F ₄ (+ N ₂ ), HBr, HI, HCl, Cl ₂ + He
It is preferable to use any combination selected from the group of By using these source gases, the etching rate ratio between the resist and the polysilane film can be increased, and the polysilane film can be etched with good dimensional control.
The reason is considered as follows. In other words, these etchants hardly cause a chemical reaction with the atoms constituting the resist and hardly generate a volatile product, while a volatile reaction having a high vapor pressure occurs due to a chemical reaction with silicon contained in the polysilane film. This is to produce a product which is easy to be processed. In particular, if a source gas containing Cl ₂ or HBr is used, the polysilane film can be etched at a high rate. As a result, even if the film thickness of the resist is reduced, the resist is not removed, and the resist pattern does not recede and the dimensional controllability of the polysilane film pattern does not deteriorate.

Finally, as shown in FIG. 1D, the resist pattern and the polysilane film pattern are used as masks.
Etch the insulating film. Examples of the etching method include reactive plasma etching, magnetron reactive plasma etching, electron beam plasma etching,
Examples include TCP plasma etching, ICP plasma etching, and ECR plasma etching. Fluorine-based gas such as CHF
₃ , C ₂ F ₆ , C ₃ F ₈ , CF ₄ + (H ₂ , C
₂ F ₂ ), C ₄ F ₈ , CHF ₃ + CO, C ₄ F ₈ + CO
Are preferred. When these source gases are used, the silicon-based insulating film can be etched at a high rate. At this time, when the deposition of the polymer film on the surface of the resist pattern or the polysilane film pattern is remarkable and the etching shape is deteriorated, it is preferable to add argon or oxygen to the source gas so that the polymer film can be removed. .

Here, after the step of FIG. 1C, a method of removing the resist pattern remaining on the polysilane film pattern and etching the insulating film using only the polysilane film pattern as a mask may be adopted. it can.

Incidentally, the polysilane of the present invention is obtained by using an electron beam, X
Since it is decomposed by high-energy radiation such as radiation, it can be expected to be applied as a resist material. In this case, depending on the combination of the type of high energy beam to be irradiated and the substituent in the organosilicon polymer, it can be used as a positive type or a negative type. This is because low-molecular-weight silane compounds decomposed and generated by high-energy rays show high solubility in a developer, and high-energy rays generate new active species and cross-link with the active species. Is advanced, and the solubility in the developer may decrease.

As described above, the polysilane of the present invention is
It can be suitably used as an etching mask material and a resist material.

In the method for producing polysilane of the present invention, a halosilane monomer having a highly reactive Si—H bond can be used as a raw material, and solid polysilane can be easily synthesized. .

[0119]

(Example 1) Anhydrous toluene 136 was placed in a four-necked flask equipped with a dropping funnel and a reflux condenser.
and a mixed solvent of 24 mL of anhydrous heptane and 0.50 g of copper (I) chloride and 13.26 g of 15-crown-5-ether (0.0602 mol) in the mixed solvent.
1), and 27.6 g (1.20 mo) of metallic sodium
1) was added and heated to the solvent reflux temperature under an argon atmosphere to prepare a sodium dispersion.

While maintaining this dispersion at the solvent reflux temperature, 58.53 g of methyldichlorosilane dissolved in a mixed solvent of 34 mL of anhydrous toluene and 6 mL of anhydrous heptane.
(0.500 mol) was dropped into the above dispersion from a dropping funnel over about 30 minutes, and further reacted at a solvent reflux temperature for 3 hours.

Subsequently, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene was used.
Was added, and the mixture was further reacted for 2 hours, and then the reaction solution was cooled to room temperature. 500 ml of toluene is added to the reaction solution after cooling.
The precipitate formed by adding was filtered under pressure under nitrogen, and the obtained filtrate was concentrated. 500 mL of ethanol was added to the solution to precipitate the polymer.

After filtering the polymer thus obtained,
The solution obtained by dissolving in toluene was washed with ion-exchanged water, and then dried over anhydrous magnesium sulfate. After removing the desiccant, the solvent was removed under reduced pressure, and 100 mL of toluene was removed.
And dissolve the toluene solution.
It was dropped into 0 ml.

Finally, the precipitate was filtered and dried under vacuum to obtain 6.56 g (29.7%) of a pale yellow solid polymer having a repeating unit represented by the following chemical formula.

[0124]

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The analysis results of the obtained polymer are summarized below.

¹ H-NMR (C ₆ D ₆ ) δ 0.26, 0.46 (SiMe), 4.02 (Si
H), 5.05 (SiH ₂ end group or
SiHCl), 5.58 (SiOH).

Integral ratio (integral area) 3.00 (0.2 to
1.0): 0.236 (3.6 to 4.4): 0.138
(4.8-5.3): trace (5.4-5.8) ^13C -NMR (ppm) -9.58, -1.71,
1.33.

IR (KBr) 2960, 2890, 2
116, 1255, 1062, 862, 768.

GPC (THF) Mw = 5000 Tg = 30 ° C. (Comparative Example 1) 160 mL of anhydrous toluene was placed in a four-necked flask equipped with a dropping funnel and a reflux condenser, and copper chloride (I) was added to the solvent. ) 0.50 g and metallic sodium 2
7.6 g (1.20 mol) was added, and the mixture was heated to the solvent reflux temperature under an argon gas atmosphere to prepare a sodium dispersion.

While maintaining this dispersion at the reflux temperature of the solvent, 58.53 g (0.500 mol) of methyldichlorosilane dissolved in 40 mL of anhydrous toluene was added dropwise from the dropping funnel into the above dispersion over about 30 minutes. Further, the mixture was reacted at the reflux temperature of the solvent for 3 hours.

Subsequently, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene was used.
Was added, and the mixture was further reacted for 2 hours, and then the reaction solution was cooled to room temperature. 500 ml of toluene is added to the reaction solution after cooling.
The precipitate formed by adding was filtered under pressure under nitrogen, and the obtained filtrate was concentrated. 500 mL of ethanol was added to the solution, but no polymer precipitated.

Therefore, the mixture was concentrated and the polymer was reprecipitated with methanol. After filtering the obtained polymer, the solution obtained by dissolving it in toluene was washed with ion-exchanged water, and then dried over anhydrous magnesium sulfate. After removing the desiccant, the solvent was removed under reduced pressure and toluene 50m
L and dissolved, and the toluene solution is dissolved in 50 ml of methanol.
It was dropped into 0 mL, but only a very small amount of precipitate was obtained.

Comparative Example 2 A four-necked flask equipped with a dropping funnel and a reflux condenser was charged with a mixed solvent of 136 mL of anhydrous toluene and 24 mL of anhydrous heptane. 13.26 g of ether (0.
060 mol), and 27.6 g of metallic sodium
(1.20 mol), and heated to the solvent reflux temperature under an argon atmosphere to prepare a sodium dispersion.

While maintaining the dispersion at the solvent reflux temperature, 58.53 g of methyldichlorosilane dissolved in a mixed solvent of 34 mL of anhydrous toluene and 6 mL of anhydrous heptane.
(0.500 mol) was dropped into the above-mentioned dispersion from a dropping funnel over about 30 minutes, and further reacted at a solvent reflux temperature for 3 hours.

Subsequently, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene was used.
Was added, and the mixture was further reacted for 2 hours, and then the reaction solution was cooled to room temperature. 500 ml of toluene is added to the reaction solution after cooling.
The precipitate formed by adding was filtered under pressure under nitrogen, and the obtained filtrate was concentrated. 500 mL of ethanol was added to the solution to precipitate the polymer.

After filtering the polymer thus obtained,
The solution obtained by dissolving in toluene was washed with ion-exchanged water, and then dried over anhydrous magnesium sulfate. After removing the desiccant, the solvent was removed under reduced pressure, and 100 mL of toluene was removed.
And dissolve the toluene solution.
It was dropped into 0 ml.

Finally, the precipitate was filtered and dried under vacuum to obtain 1.61 g (7.3%) of a polymer.

GPC (THF) Mw = 2000.

From the results of Comparative Example 1, it was found that Si-
In the polymerization of a dihalosilane monomer having an H bond, it was revealed that the effect of adding a copper compound would not be obtained unless a crown ether as an ether compound was present. In addition, even when crown ether was added, when no copper compound was present, the results of Comparative Example 2 showed that the weight average molecular weight of the obtained polysilane was as low as about 2000 and the yield was as low as 7%. ing.

That is, the polysilane of Example 1 synthesized in the presence of an ether compound and a copper compound was obtained in Comparative Example 2
The weight average molecular weight was 2.5 times as high as that obtained in the above, and the yield could be greatly improved to about 3 times.

Example 2 A mixed solvent of 136 mL of anhydrous toluene and 24 mL of anhydrous heptane was placed in a four-necked flask equipped with a dropping funnel and a reflux condenser, and copper (I) chloride was added to the mixed solvent. 0.50 g, 15-crown-5
13.24 g (0.0602 mol) of ether and 27.6 g (1.20 mol) of sodium metal were added,
The mixture was heated to the reflux temperature of the solvent under an argon atmosphere to prepare a sodium dispersion.

While maintaining the dispersion at the solvent reflux temperature, 64.53 g of ethyldichlorosilane dissolved in a mixed solvent of 34 mL of anhydrous toluene and 6 mL of anhydrous heptane.
(0.500 mol) was dropped into the above dispersion from a dropping funnel over about 30 minutes, and further reacted at a solvent reflux temperature for 3 hours.

Subsequently, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene was used.
Was added, and the mixture was further reacted for 2 hours, and then the reaction solution was cooled to room temperature. 500 ml of toluene is added to the reaction solution after cooling.
The precipitate formed by adding was filtered under pressure under nitrogen, and the obtained filtrate was concentrated. 500 mL of ethanol was added to the solution to precipitate the polymer.

After filtering the thus obtained polymer,
The solution obtained by dissolving in toluene was washed with ion-exchanged water, and then dried over anhydrous magnesium sulfate. After removing the desiccant, the solvent was removed under reduced pressure, and 100 mL of toluene was removed.
And dissolve the toluene solution.
It was dropped into 0 ml.

Finally, the precipitate was filtered and dried under vacuum to obtain 9.45 g (32.5%) of a pale yellow solid polymer having a repeating unit represented by the following chemical formula.

[0146]

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Example 3 A four-necked flask equipped with a dropping funnel and a reflux condenser was charged with a mixed solvent of 136 mL of anhydrous toluene and 24 mL of anhydrous heptane, and copper (I) chloride was added to the mixed solvent. 0.50 g, 15-crown-5
13.24 g (0.0602 mol) of ether and 27.6 g (1.20 mol) of sodium metal were added,
The mixture was heated to the reflux temperature of the solvent under an argon atmosphere to prepare a sodium dispersion.

While maintaining the dispersion at the solvent reflux temperature, 78.55 g of hexyldichlorosilane dissolved in a mixed solvent of 34 mL of anhydrous toluene and 6 mL of anhydrous heptane.
(0.500 mol) was dropped into the above dispersion from a dropping funnel over about 30 minutes, and further reacted at a solvent reflux temperature for 3 hours.

Subsequently, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene was used.
Was added, and the mixture was further reacted for 2 hours, and then the reaction solution was cooled to room temperature. 500 ml of toluene is added to the reaction solution after cooling.
The precipitate formed by adding was filtered under pressure under nitrogen, and the obtained filtrate was concentrated. 500 mL of ethanol was added to the solution to precipitate the polymer.

After filtering the polymer thus obtained,
The solution obtained by dissolving in toluene was washed with ion-exchanged water, and then dried over anhydrous magnesium sulfate. After removing the desiccant, the solvent was removed under reduced pressure, and 100 mL of toluene was removed.
And the toluene solution is dissolved in ethanol 10
It was dropped into 00 ml.

Finally, the precipitate was filtered and dried under vacuum to obtain 17.67 g (41.0%) of a pale yellow solid polymer having a repeating unit represented by the following chemical formula.

[0152]

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Example 4 A solution was prepared by dissolving 2 g of the poly (methylhydrosilane) obtained in Example 1 in 8 g of toluene. This solution was spin-coated on a silicon substrate and heated at 120 ° C. for 1 minute. At this time, the film thickness was 0.87 μm.

Then, after heating in air at 290 ° C. for 10 minutes, and then heating in a nitrogen atmosphere at 450 ° C. for 1 hour, a siloxane-based insulating film (0.93 μm thick) was formed. The dielectric constant of this insulating film was measured.
It was 7.

[0155] From FT-IR measurement of the membrane, the absorption based on Si-H has completely disappeared, the absorption of the methyl group is present in 2964Cm ^-1, absorption based on Si-CH ₃ is the 1276Cm ^-1 It was present and absorption based on Si-O-Si was observed at 1133 cm ^-1 and 1038 cm ^-1 .
From these results, the Si—Si bond of the polysilane film and S
The i-H bond is oxidized to form a Si-O-Si bond,
It was confirmed that a network-like siloxane-based insulating film was formed.

Example 5 2 g of the poly (ethylhydrosilane) obtained in Example 2 was dissolved in 8 g of toluene to prepare a solution. This solution was spin-coated on a silicon substrate and heated at 120 ° C. for 1 minute. Then, after heating in air at 290 ° C. for 10 minutes,
By heating at 50 ° C. for 1 hour, a siloxane-based insulating film was formed. The dielectric constant of this film was measured.
It was 6.

Example 6 2 g of the poly (methylhydrosilane) obtained in Example 1 was dissolved in 8 g of toluene to prepare a solution. This solution was spin-coated on a silicon substrate to form a polysilane film. This polysilane film is irradiated with light of a wavelength of 254 nm through a predetermined mask.
After exposure to 00 mJ, a developer (ethanol (25 vol.)
%) + Tetrabutylammonium hydroxide aqueous solution (75 vol%)) to form a 0.5 μm L / S pattern.

The obtained pattern was heated and oxidized under the same conditions as in the formation of the siloxane film in Example 5, and the pattern was observed. As a result, no crack or peeling was observed.

(Example 7) Potassium disilicide 4.0
g was ground and suspended in 150 mL of dry carbon tetrachloride. While stirring this suspension in an oil bath at 40 ° C. under an argon atmosphere, a solution of 67.4 g of iodine monochloride in carbon tetrachloride (50 mL) was added dropwise over 30 minutes. After stirring the obtained mixed solution at 40 ° C. for 24 hours, the reaction solution was concentrated, and iodine was further sublimated and removed.

Next, the mixture was extracted with carbon tetrachloride, filtered, and the filtrate was concentrated to obtain 4.0 g of a reddish brown resinous chloropolysilane. This chloropolysilane was dissolved in 100 mL of ether, and 1.5 equivalents of a methyllithium ether solution (1.4 M) was added dropwise while cooling in an ice water bath. After stirring the obtained mixed solution at room temperature for 20 hours, methanol 20
mL was added dropwise to decompose excess methyllithium, the solvent and methanol were removed under reduced pressure, and then extracted with carbon tetrachloride. After concentration of the solvent, 1.5 g of a red-orange resinous methylpolysilane was obtained. Reprecipitation was obtained with toluene / methanol.

GPC (THF) Mw = 11000 (Example 8) Disilane (50%,
1,1,2,2-tetrachlorosilane-1,2-dimethyldisilane and 50% 1,1,2-trichlorosilane
100 g of 1,2,2-trimethyldisilane mixture)
Tetrabutylphosphonium chloride (Bu ₄ PC
l) Add 1.0 g and heat to 90 ° C., Bu ₄ PCl
Was dissolved. The obtained solution was gradually heated to 250 ° C. and heated at 250 ° C. for 1 hour.

The reaction product was distilled to remove volatile components, thereby obtaining 10 g of poly (methylsilane) as a yellow solid.
The whole amount of poly (methylsilane) was dissolved in 100 mL of toluene, and 0.5 equivalent of a methyllithium ether solution (1.4 M) was added dropwise while cooling in an ice water bath. After stirring the obtained mixed solution at room temperature for 20 hours, methanol 20m
1 was added dropwise to decompose excess methyllithium, the solvent and methanol were removed under reduced pressure, and then extracted with toluene.

After concentration of the solvent, a yellow resinous methylpolysilane was obtained. The precipitate was reprecipitated with toluene / methanol to obtain 2.8 g of a yellow resinous methylpolysilane.

GPC (THF) Mw = 15000
Example 9 First, 10 g of polysilane (Si-H content 30%) represented by the following chemical formula was added to cyclohexanone 1
A solution was prepared by dissolving the solution in 00 g.

[0165]

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On a silicon wafer, a 500 nm thick S
An iO ₂ film was formed, and the above-mentioned solution was applied on the SiO ₂ film and baked to form a 250 nm-thick polysilane film.

By heating at 240 ° C. for 5 minutes in a nitrogen atmosphere, the polysilane film was crosslinked and insolubilized. Next, a positive chemically amplified resist TDUR-P007 was applied on the polysilane film and baked at 89 ° C. for 120 seconds to form a resist film having a thickness of 250 nm. KrF
Using a reduction exposure type stepper using an excimer laser as a light source, exposure was performed through a mask at an exposure amount of 30 mJ / cm ² and baked at 98 ° C. for 120 seconds. The exposed resist film is developed with a 0.21N TMAH developing solution,
An 8 μm line and space resist pattern was formed. When the cross section of the obtained resist pattern was observed by SEM, no wavy shape due to a standing wave was recognized on the side wall of the resist pattern. Using the resist pattern as a mask, the HBr flow rate is 50 sccm, and the degree of vacuum is 80 mT.
When the polysilane film was etched under the conditions of orr and an excitation power of 200 W, a pattern of the polysilane film having vertical side walls was formed. The resist remained on this upper portion, and it was found that the resist had a sufficient etching rate ratio.

Next, using the polysilane film as a mask, C ₄
F ₈ flow rate 50 sccm, CO flow rate 10 sccm, Ar flow rate 100 sccm, O ₂ flow rate 3 sccm, degree of vacuum 10 m
The SiO ₂ film was etched under the conditions of Torr and excitation power of 200 W. The etching resistance of the polysilane film was sufficient, and a SiO ₂ film pattern having vertical side walls was obtained.
The remaining polysilane film could be easily peeled off with an organic alkali aqueous solution or a diluted hydrofluoric acid aqueous solution.

(Example 10) First, 10 g of polysilane (Si-H content: 30%) represented by the following chemical formula,
TB 3g, DAF 3g, and AA-1 0.1g
Was dissolved in 100 g of cyclohexanone to prepare a solution.

[0170]

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On a silicon wafer, a 500 nm thick S
An iO ₂ film was formed, and the above solution was applied on the SiO ₂ film and baked to form a 250 nm-thick polysilane film.

The polysilane film was crosslinked and insolubilized by heating at 200 ° C. for 5 minutes in a nitrogen atmosphere. Next, a positive chemically amplified resist TDUR-P007 was applied on the polysilane film and baked at 89 ° C. for 120 seconds to form a resist film having a thickness of 250 nm. KrF
Using a reduction exposure type stepper using an excimer laser as a light source, exposure was performed through a mask at an exposure amount of 30 mJ / cm ² and baked at 98 ° C. for 120 seconds. The exposed resist film is developed with a 0.21N TMAH developing solution,
An 8 μm line and space resist pattern was formed. When the cross section of the obtained resist pattern was observed by SEM, no wavy shape due to a standing wave was recognized on the side wall of the resist pattern. Using the resist pattern as a mask, the HBr flow rate is 50 sccm, and the degree of vacuum is 80 mT.
When the polysilane film was etched under the conditions of orr and an excitation power of 200 W, a pattern of the polysilane film having vertical side walls was formed. The resist remained on this upper portion, and it was found that the resist had a sufficient etching rate ratio.

Next, using the polysilane film as a mask, C ₄
F ₈ flow rate 50 sccm, CO flow rate 10 sccm, Ar flow rate 100 sccm, O ₂ flow rate 3 sccm, degree of vacuum 10 m
The SiO ₂ film was etched under the conditions of Torr and excitation power of 200 W. The etching resistance of the polysilane film was sufficient, and a SiO ₂ film pattern having vertical side walls was obtained.
The remaining polysilane film could be easily peeled off with an organic alkali aqueous solution or a diluted hydrofluoric acid aqueous solution.

Example 11 First, 10 g of a polysilane (Si-H content: 25%) represented by the following chemical formula, 3 g of decaphenylpentasilyl-1,5-diol, BTT
B 3 g and AA-20.1 g were added to cyclohexanone 100
g to prepare a solution.

[0175]

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On a silicon wafer, a 500 nm thick S
An iO ₂ film was formed, and the above-mentioned solution was applied on the SiO ₂ film and baked to form a 250 nm-thick polysilane film.

The polysilane film was crosslinked and insolubilized by heating at 160 ° C. for 5 minutes in a nitrogen atmosphere. Next, a positive chemically amplified resist TDUR-P007 was applied on the polysilane film and baked at 89 ° C. for 120 seconds to form a resist film having a thickness of 250 nm. KrF
Using a reduction exposure type stepper using an excimer laser as a light source, exposure was performed through a mask at an exposure amount of 30 mJ / cm ² and baked at 98 ° C. for 120 seconds. The exposed resist film is developed with a 0.21 N TMAH developing solution to obtain 0.18
A μm line and space resist pattern was formed. When the cross section of the obtained resist pattern was observed by SEM, no wavy shape due to a standing wave was recognized on the side wall of the resist pattern. Using the resist pattern as a mask, Cl ₂ flow rate 50 sccm, vacuum degree 80 mTo
When the polysilane film was etched under the conditions of rr and excitation power of 200 W, a pattern of the polysilane film having vertical side walls was formed. The resist remained on this upper portion, and it was found that the resist had a sufficient etching rate ratio.

Next, using the polysilane film as a mask, C ₄
F ₈ flow rate 50 sccm, CO flow rate 10 sccm, Ar flow rate 100 sccm, O ₂ flow rate 3 sccm, degree of vacuum 10 m
The SiO ₂ film was etched under the conditions of Torr and excitation power of 200 W. The etching resistance of the polysilane film was sufficient, and a SiO ₂ film pattern having vertical side walls was obtained.
The remaining polysilane film could be easily peeled off with an organic alkali aqueous solution or a diluted hydrofluoric acid aqueous solution.

It has been confirmed from the results of the above examples that the polysilane of the present invention is suitably used as an insulating film material and a resist material. Further, according to the method of the present invention, it has become possible to easily synthesize a solid polysilane that can be suitably used for such an application from a halosilane monomer having a highly reactive Si—H bond in a high yield. .

[0180]

As described in detail above, according to the present invention, there is provided a polysilane which is soluble in an organic solvent, can be easily formed into a thin film, and can form a film having high mechanical strength. Further, according to the present invention, there is provided a method capable of safely and easily synthesizing such a polysilane in a high yield.

The polysilane of the present invention is an optimum material as a low dielectric constant insulating material capable of patterning, an etching mask material or a resist material, and the method of the present invention is extremely suitable for polymerization of general halosilane monomers. It can be applied as an effective synthesis method, and its industrial value is enormous.

[Brief description of the drawings]

FIG. 1 is a view showing a process for processing a silicon oxide film using a polysilane of the present invention as an antireflection film.

[Explanation of symbols]

 11 silicon substrate 12 insulating film 13 polysilane film 14 resist film

Claims (6)

[Claims] 1. A polysilane containing a copolymer which is soluble in an organic solvent, has a glass transition temperature of −40 ° C. or higher, and contains a repeating unit represented by the general formula (1). Embedded image (In the above general formula (1), R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms, and a is 0.1 or more and 0.1 or more.
9 or less. ) 2. The polysilane according to claim 1, wherein the copolymer contains a repeating unit represented by the following general formula (2). Embedded image (In the general formula (2), R ⁰ represents a substituted or unsubstituted aliphatic or aromatic hydrocarbon group having 20 or less carbon atoms, and Ar represents a substituted or unsubstituted having 20 or less carbon atoms. Represents an aromatic hydrocarbon group.) 3. The polysilane according to claim 1, further comprising an antioxidant. 4. The polysilane according to claim 1, wherein the content of Si—H bonds in the whole polysilane is 90% or less. 5. A method for synthesizing a polysilane represented by the following general formula (1) or the following general formula (3): (In the above formula, R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms, a is 0.1 or more and 0.9 or less. R ¹ and R ² may be the same or different. Well,
A hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group or an aromatic hydrocarbon group, respectively. A) a step of adding a copper compound, an ether compound and an alkali metal to a solvent and heating to obtain an alkali metal dispersion; and a step of dropping a halosilane compound dissolved in a solvent into the dispersion to obtain a reaction product. Adding trimethylsilane dissolved in a solvent to the reaction product, and further reacting the reaction product. 6. The method according to claim 5, wherein the ether compound is a crown ether or a derivative thereof, or an ethylene glycol derivative.