JP3481852B2 - Polysilane and method for synthesizing polysilane - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polysilane and a method for synthesizing polysilane, and more particularly, photoresist,
Antireflection film, precursor of insulating material, photoconductor, light emitting material,
The present invention relates to a polysilane useful as a charge transport material or a nonlinear optical material, and a method for synthesizing polysilane.

[0002]

Various methods have been reported so far for the synthesis of poly (alkylhydrosilane) s.
Most of them relate to the synthesis of poly (methylhydrosilane). In the general synthetic method of polycondensation of dichlorosilane with sodium metal, only oily polysilane having an average molecular weight of about 1000 is obtained (Mauricio F. Gozzi et al., Macr.
OMolecules, 1995, 28, 7235).

Such low molecular weight polysilane has many practical problems such as weak mechanical strength when formed into a film.
Although other methods have been used to synthesize poly (alkylhydrosilanes), each method has various drawbacks. For example, a method of synthesizing poly (alkylhydrosilane) by a plasma CVD method using alkylsilane (RSiH ₃ ) has been reported (Timoth.
y W. Weidman et al., Appl. Phys. Le
tt. 62 (4), 372, 1993). However, this method has a problem in safety because it uses an alkylsilane monomer that easily causes ignition or explosion in the air, and also has a problem that cost is increased because CVD is used.

Further, as a method for synthesizing polysilane, there is a method for obtaining polysilane by dehydrogenative condensation of monosubstituted silane (RSiH ₃ ) with a titanocene or zirconenecene-based catalyst (JF Harrod, ACS, Polym. P.
repr. , 28, 403 (1987)). When synthesized by this method, the degree of polymerization of the obtained polysilane is increased to about 20, and there is a drawback that some metal catalyst remains in the further purified polymer and cannot be removed.

On the other hand, as a method for synthesizing polysilane, a method of polycondensing dichlorosilane with metallic sodium has been mainly used as the most general synthetic method. However, this polycondensation reaction has a problem in that the control is difficult and the yield of the obtained high molecular weight polysilane is poor. In order to solve this problem, a method of adding a crown ether has been proposed (DJ Worsfol).
d et al., Macromolecules, 22, 2213.
(1989)). Although the yield is increased by adding the crown ether, there are disadvantages that the molecular weight distribution is largely changed and the average molecular weight is significantly reduced.
Further, it has been reported that high-molecular-weight polysilane can be obtained in a high yield by carrying out the above-mentioned polycondensation reaction in the presence of a copper compound (JP-A-4-185642). However, in that example, it is limited to the polycondensation reaction using a general monomer such as phenylmethyldichlorosilane,
The effect of polysilane synthesis from alkylhydrodichlorosilanes (RHSiCl) having a highly reactive Si-H bond has not been confirmed.

[0006]

As described above, the present situation is that polysilane having a high molecular weight which can be preferably used for an antireflection film and the like, and which has a small residual amount of a metal catalyst 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 been found yet.

Therefore, an object of the present invention is to provide 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 problems, the present invention provides the following general formula (1) or the following general formula.
A method for synthesizing polysilane represented by (3) , comprising:

[Chemical 18]

[0010]

[0011]

(In the above general 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. They may be different, and each is 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,
A step of heating to obtain an alkali metal dispersion, a step of 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. And a step of further reacting, and a step of washing the obtained reaction product with ion-exchanged water. Furthermore, the present invention is soluble in an organic solvent, has a glass transition temperature of −40 ° C. or higher, has 0.1 to 0.9 mole fraction of the repeating unit represented by the general formula (1), and occupies the balance below. Polysilane containing a copolymer containing a repeating unit represented by the chemical formula shown in
(However, R in the general formula (1) is a methyl group,
The repeating unit occupying the balance is [1-2] or [1-2]
2] and R is a trifluoropropyl group
Yes, and the repeating unit occupying the balance is [1-8]
Repeat, where R is a hexyl group and occupies the rest
The unit is [1-50], and R is
A repeating unit that is a rifluorobutyl group and occupies the rest
Exclude combinations that are [1-51]. ) Is provided.

[Chemical formula 18] (In the 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.
It is 9 or less. )

[Chemical formula 19]

[Chemical formula 20]

[Chemical formula 21]

[Chemical formula 22]

[Chemical formula 23]

[Chemical formula 24]

[Chemical formula 25]

[Chemical formula 26]

[Chemical formula 27]

[Chemical formula 28]

[Chemical formula 29]

[Chemical formula 30]

[Chemical formula 31]

[Chemical Formula 32]

[Chemical Formula 33]

The present invention will be described in detail below.

The polysilane of the present invention has the general formula (1) above.
It is a copolymer having a repeating unit represented by 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 group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, cyclohexyl group, 3,3,3. Examples thereof include 3-trifluoropropyl group and 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, not only the polymer becomes liquid but also it is easily oxidized, while when it exceeds 0.9, it may become insoluble. Note that a is
It is more preferably 0.4 to 0.7.

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

[0017]

[Chemical 6]

The repeating unit represented by the general formula (1) is preferably contained in the copolymer of the present invention in a polysilane content of about 0.1 to 0.9 in terms of mole fraction. . If it is less than 0.1, the effect of Si—H bond is difficult to be obtained, while if it exceeds 0.9, it may be easily oxidized.

In the present invention, the copolymer containing the repeating unit represented by the general formula (1) has a molecular weight of 500.
It is preferably 100 to 100,000, and 1000 to 1
More preferably, it is 10,000. If it is less than 500, the polymer becomes liquid, while if it exceeds 100,000, it may become insoluble.

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

[0021]

[Chemical 7]

[0022]

[Chemical 8]

[0023]

[Chemical 9]

[0024]

[Chemical 10]

[0025]

[Chemical 11]

[0026]

[Chemical 12]

[0027]

[Chemical 13]

[0028]

[Chemical 14]

[0029]

[Chemical 15]

[0030]

[Chemical 16]

[0031]

[Chemical 17]

[0032]

[Chemical 18]

[0033]

[Chemical 19]

[0034]

[Chemical 20]

[0035]

[Chemical 21]

Among these repeating units, the repeating unit represented by the following general formula (2) is particularly preferable.
By including this repeating unit, the stability against oxidation and the effect of Si—H bond (crosslinking property, reactivity) can be made compatible.

[0037]

[Chemical formula 22]

(In the above general formula (2), R ⁰ is 2 carbon atoms.
It represents a substituted or unsubstituted aliphatic hydrocarbon group 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, as R ⁰ , for example, a methyl group, an ethyl group,
Examples thereof 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 the repeating unit represented by the general formula (2) is contained, the effect is exhibited when the content of the repeating unit is about 20 mol% in the copolymer of the present invention. However, when it is contained excessively, the Si content may be lowered, so that the proportion thereof is preferably about 90 mol% or less in the copolymer.

The polysilane of the present invention, which is a copolymer having the 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.

In the copolymer of the present invention, Si-
The content of H bonds is preferably 90% or less, and S
More preferably, 10% or more of i-H bonds are crosslinked. This is because if the Si-H bond content exceeds 90%, it may be oxidized.

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

The following chemical formulas show examples of antioxidants that can be used in the present invention.

[0044]

[Chemical formula 23]

[0045]

[Chemical formula 24]

A crosslinking agent may be blended with the polysilane of the present invention. As the cross-linking agent, an organic substance having multiple bonds can be used. The organic substance having a multiple bond is a compound having a double bond or a triple bond, and more specifically, a compound having a vinyl group, an acryl group, an aryl group, an imide group, an acetylenyl group and derivatives thereof. The organic group having such a multiple bond may be a monomer, an oligomer or a polymer.

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

[0048]

[Chemical 25]

[0049]

[Chemical formula 26]

[0050]

[Chemical 27]

[0051]

[Chemical 28]

[0052]

[Chemical 29]

[0053]

[Chemical 30]

[0054]

[Chemical 31]

[0055]

[Chemical 32]

[0056]

[Chemical 33]

[0057]

[Chemical 34]

As described above, when a compound having multiple bonds 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 of promoting 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, alkyl aryl ketones, silyl peroxides, organic halides and the like. The radical generator decomposes an O—O bond or a C—C bond in the molecule by light irradiation or heating to generate a radical. As the radical generator, for example, those listed below can be used.

[0060]

[Chemical 35]

When an oxide is used, it 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 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 polycondensation reaction is carried out in a solvent using an alkali metal as a catalyst in the presence of a copper compound as a cocatalyst and an ether compound. Alternatively, it can be synthesized by 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 compounds represented by the following general formula (4).

[0065]

[Chemical 36]

(In the above general formula (4), R ¹ and R
² may be the same or different and each is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group or an aromatic hydrocarbon group. X is a halogen atom. Further, in the halosilane compound, a monomer in which halosilane is bound 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} above general formula (4) include methyl group, ethyl group, propyl group, butyl group, cyclohexyl group, dodecyl group and substitution thereof. The body etc. are mentioned.
In addition, 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, but 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 chemical formulas below.

[0070]

[Chemical 37]

[0071]

[Chemical 38]

[0072]

[Chemical Formula 39]

In particular, a compound represented by the general formula (4) represented by the following general formula (5), that is, R in the 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]

[Chemical 40]

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

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

Specific examples of the compound represented by the general formula (5) are shown below.

[0078]

[Chemical 41]

[0079]

[Chemical 42]

In synthesizing polysilane by the method of the present invention using the above-mentioned halosilane compound as a raw material, first, for example, a predetermined amount of a copper compound, an ether compound and an alkali metal are added to an organic solvent, and 100 Heat to about 120 ° C. to prepare an alkali metal dispersion.

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

As the copper compound, for example, copper halide,
Examples thereof include, but are not limited to, copper acetate, copper acetylacetonate, and copper cyanide. The addition amount is 0.1 to 10 mol% with respect to the halosilane monomer.

Examples of ether compounds include crown ethers and their derivatives, tetrahydrofuran, ethylene glycol derivatives such as diglyme; dioxane,
Tetraoxane, cryptant, etc. are mentioned. For example, crown ethers include 1,4-dioxane, 1,3,5-trioxane, 15-crown-
Examples thereof include 5,12-crown-4, 18-crown-6, benzo-18-crown-6, and the like, but are not particularly limited. Examples of the crown ether derivative include crown ether analogs, such as N, N'-dimethylpiperazine, 4-methylmorpholine and 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] hexacosane, 1,4,7,10,
Examples thereof include 13,16-hexathiacyclooctadecane, but are not particularly limited. The amount of the crown ether and the crown ether analog compound added is 1 to 100 mol% with respect to the halosilane monomer.

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

Examples of the alkali metal include sodium metal, Li, K and the like, but sodium metal is preferable in view of easy handling. The addition amount is 0.9 to 2.0 mo with respect to the halosilane monomer.
Used at 1%.

On the other hand, a predetermined amount of 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 those described above.

A solution containing a halosilane compound is added dropwise to the dispersion obtained as described above at a rate at which reflux continues, and the reaction is carried out at the 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, and the reaction is carried out for about 30 minutes to 2 hours, followed by cooling to room temperature.

Next, twice the amount of toluene is added to the cooled reaction solution to precipitate NaCl, and the precipitate is filtered under pressure in a nitrogen atmosphere to concentrate the filtrate.

To the concentrated solution was added 10 times the amount of ethanol of toluene to precipitate the polymer, and the obtained polymer was filtered and dissolved in toluene. This toluene solution is washed with ion-exchanged water and then dried with a desiccant such as anhydrous magnesium sulfate.

Then, after removing the desiccant, the solvent is removed under reduced pressure to obtain a solid product, which is dissolved in toluene. The toluene solution is dropped into ethanol or the like to deposit a precipitate.

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

When the copolymerization monomer is added at the same time as the step of adding the halosilane in the above-mentioned method,
A copolymer containing the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (2) can be synthesized.

Polysilane can also be synthesized by the same method as described above except that a tertiary amine compound is used instead of the ether compound. In this case, examples of the tertiary amine compound that can be used include N, N, N ′, N′-tetramethylethylenediamine, N, N-dimethylaniline, N, N, N ′, N ′, N ″- Pentamethyldiethylenetriamine and the like are mentioned, and the addition amount thereof is preferably about 0.1 to 100 mol% with respect to the halosilane monomer.

Alternatively, a halosilane compound and a silane compound represented by the following general formula (6) or (7) in which three or more halogen atoms are substituted are used to copolymerize to obtain a crosslinked polysilane copolymer. The polymer can be easily synthesized.

[0096]

[Chemical 43]

(In the above general 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 thereof 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 substituted products 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]

[Chemical 44]

Since the polysilane of the present invention has a glass transition temperature of -40 ° C. or higher, it has the 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 hydrocarbon type, aromatic hydrocarbon type, ether type, and halogen type solvents, it can be easily formed into a film by a coating method such as spin coating. Furthermore, since the polysilane of the present invention has a sufficient degree of crosslinking, the film obtained by forming such a polysilane is also excellent in mechanical strength. Further, the polysilane of the present invention is advantageous in that it highly absorbs ultraviolet rays having a wavelength of 280 nm or less 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 of processing a silicon-based insulating film using an antireflection film formed of polysilane according to the present invention will be described. Note that Ta
Insulating films such as O ₂ and RuO ₂ , AlSi and AlSiC
Processing of a conductive film of u, Ti salicide, Co salicide, Cu or the like can be performed in the same process.

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

The thickness of the polysilane film is preferably about 20 to 500 nm. The film 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 multiple reflection of exposure light, and the film thickness is set so that the reflectance becomes as small as possible. 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 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) and the like.

(2) The resist pattern is used as a mask for etching, and the etched polysilane film is used as a mask for etching the insulating film.

The polysilane film is formed by applying a solution in which polysilane is dissolved in an organic solvent and then baking it to vaporize the solvent. The organic solvent used at this time may be a polar solvent or a nonpolar solvent. As the polar solvent, ether solvents (for example, diethyl ether, dibutyl ether, tetrahydrofuran, anisole), cellosolve solvents (for example, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate),
Examples thereof include ester solvents (eg ethyl acetate, butyl acetate, isoamyl acetate). Examples of the nonpolar solvent include toluene, xylene, hexane, octane, cumene, solvent naphtha and the like. A halogen-based solvent (methylene chloride, chlorobenzene, chloroform, etc.) can also be used as the solvent for the polysilane dendrimer. 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 polysilane is 500 to 1
000000 is preferable, and 2000 to 100000 is more preferable. This is because when Mw is less than 500, the mechanical strength is poor when dissolved in a solvent and applied to form a film, and when Mw exceeds 1,000,000, the solubility in the solvent decreases. Polysilane may be used alone or 2
You may use it in mixture of 2 or more types.

If necessary, the polysilane film has an adhesion improver for improving the adhesion to the base; a dye absorbing ultraviolet rays for preventing reflected light from the insulating film into the resist film or A polymer (for example, polysulfone, polybenzimidazole); a surfactant for improving the wettability with the base, or the like may be added. In this case, the compounding amount of the additive is adjusted so that the silicon content in the polysilane film containing the additive formed by 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 furthermore, a sufficient etching rate ratio cannot be obtained when the polysilane film is etched 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 coatability, and pinholes are likely to occur in the film.

The resist film is formed by applying a resist solution on the polysilane film and then baking the resist solution. The thinner the resist film is, the more the exposure dose margin, the focus margin, or the resolution at the time of exposure can be improved. Therefore, the film thickness of the resist film is preferably as thin as possible within the range in which the polysilane film can be etched with good dimension control, 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 novolac resin (IX-770, manufactured by Japan Synthetic Rubber Co., Ltd.), t-BOC.
And a chemically amplified resist (APEX-E, manufactured by Shipley Co., Ltd.) composed of a polyvinylphenol resin protected with and an onium salt. As the negative resist, for example, a chemically amplified resist (XP-89131, manufactured by Shipley) consisting of polyvinylphenol, a melamine resin and a photoacid generator, a resist consisting of polyvinylphenol and a bisazide compound (RD-200D) are used. , Manufactured by Hitachi Chemical Co., Ltd.) and the like. In order to prevent the dimensional controllability of the resist pattern from deteriorating due to standing waves generated in the resist film, a dye such as coumarin or curcumin that absorbs ultraviolet rays is added to the resist to reduce the transparency of the resist. Good.

A film having a thickness of about 10 to 150 nm is provided between the polysilane film and the resist film in order to more surely prevent the exposure light reflection from the underlayer to the resist film and form the resist profile after development into a good shape. A thick thin film may be formed. Examples of the material of the thin film formed for this purpose and the film forming method thereof include the following. 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. Further, a solution of a polymer such as polysulfone, polyamide, novolac resin, or polyhydroxystyrene 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, by forming an upper antireflection film on the resist film to reduce the light reflection at the interface between the resist film and the air, it is possible to suppress the generation of standing waves in the resist film. Good. As such an upper antireflection film, for example, Aquatar manufactured by Hoechst Co. and the like can be mentioned.

Next, as shown in FIG. 1B, a resist pattern is formed by irradiating the resist with ultraviolet light as exposure light through a mask having a desired pattern and developing the resist. A mercury lamp, XeF (wavelength = 351 nm), Xe is used as a light source for irradiating ultraviolet light.
Cl (wavelength = 308 nm), KrF (wavelength = 248n)
m), KrCl (wavelength = 222 nm), ArF (wavelength =
193 nm), F ₂ (wavelength = 151 nm) and other excimer lasers. The polysilane of the present invention is Si-
Since it has Si and has high absorptivity to ultraviolet rays having a wavelength of 150 to 360 nm, it can absorb exposure light and suppress light reflected into the resist film. As a result, no wavy shape due to standing waves is observed in the resist profile after development.
In addition, even if the resist film thickness and the insulating film thickness vary,
It is possible to suppress the variation amount of the resist pattern dimension.
As the resist developing solution, an organic alkaline aqueous solution such as tetramethylammonium hydroxide, sodium hydroxide,
An inorganic alkaline 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. As a source gas, CF ₄ , CF ₃ Cl, CF ₂
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 preferred to use any combination selected from the group By using these source gases, the etching rate ratio between the resist and the polysilane film can be made high, and the polysilane film can be etched with good dimensional controllability.
The reason for this is considered as follows. That is, these etchants are unlikely to chemically react with the atoms constituting the resist to generate a volatile product, whereas they are chemically reacted with silicon contained in the polysilane film to have a high vapor pressure. This is to produce a product that is easy to handle. In particular, the source gas containing Cl ₂ or HBr can be used to etch the polysilane film at a high speed ratio. As a result, even if the resist film thickness is reduced, the resist is not scraped off, and the resist pattern recedes so that the dimensional controllability of the polysilane film pattern does not deteriorate.

Finally, as shown in FIG. 1D, using the resist pattern and the polysilane film pattern as a mask,
Etch the insulating film. As the etching method, for example, reactive plasma etching, magnetron reactive plasma etching, electron beam plasma etching,
Examples include TCP plasma etching, ICP plasma etching, and ECR plasma etching. As the source gas, a 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 ratio. At this time, when the polymer film is remarkably deposited on the surface of the resist pattern or the polysilane film pattern 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.

The polysilane of the present invention is prepared by using an electron beam, X
Since it decomposes with high energy rays such as rays, it can be expected to be applied as a resist material. In this case, depending on the combination of the type of high energy ray 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 when a low-molecular-weight silane-based compound decomposed and produced by high energy rays has high solubility in a developer, active species are newly generated by high energy rays and crosslinking occurs due to reaction with this active species. In some cases, and the solubility in the developing solution may decrease.

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

In addition, 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]

BEST MODE FOR CARRYING OUT THE INVENTION (Example 1) In a four-necked flask equipped with a dropping funnel and a reflux condenser, anhydrous toluene 136 was added.
A mixed solvent of 24 mL of anhydrous heptane was stored, and 0.50 g of copper (I) chloride and 13.26 g of 15-crown-5-ether (0.0602mo) were contained in this mixed solvent.
1), and 27.6 g (1.20 mo) of sodium metal.
1) was added, and the mixture was heated to a 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 added dropwise to the above dispersion through the dropping funnel over about 30 minutes, and further reacted at the solvent reflux temperature for 3 hours.

Then, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene.
Was added and the mixture was reacted for another 2 hours, and then the reaction solution was cooled to room temperature. To the reaction solution after cooling, 500 ml of toluene
Was added to the reaction mixture, and the resulting precipitate was pressure-filtered 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, remove the solvent under reduced pressure, and add 100 mL of toluene.
Is added and dissolved, and this toluene solution is added with ethanol 100
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]

[Chemical formula 45]

The analytical 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).

Integration ratio (integration area) 3.00 (0.2 to
1.0): 0.236 (3.6 to 4.4): 0.138
(4.8 to 5.3): trace (5.4 to 5.8) ¹³ C-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 ) 0.50 g and sodium metal 2
7.6 g (1.20 mol) was added, and the mixture was heated to a solvent reflux temperature under an argon gas atmosphere to prepare a sodium dispersion.

While keeping the dispersion at the solvent reflux temperature, 58.53 g (0.500 mol) of methyldichlorosilane dissolved in 40 mL of anhydrous toluene was dropped into the above dispersion through a dropping funnel over about 30 minutes. Further, the reaction was carried out at the solvent reflux temperature for 3 hours.

Next, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene.
Was added and the mixture was reacted for another 2 hours, and then the reaction solution was cooled to room temperature. To the reaction solution after cooling, 500 ml of toluene
Was added to the reaction mixture, and the resulting precipitate was pressure-filtered under nitrogen, and the obtained filtrate was concentrated. 500 mL of ethanol was added to the solution, but the polymer did not precipitate.

Therefore, the mixed solution was concentrated and the polymer was reprecipitated with methanol. The obtained polymer was filtered, dissolved in toluene, and the resulting solution 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 was added and dissolved, and this toluene solution was added with methanol 50
It was added dropwise to 0 mL, but only a very small amount of precipitate was obtained.

(Comparative 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 15-crown-5 was added to this mixed solvent. 13.26 g of ether (0.
060 mol), and 27.6 g of metallic sodium
(1.20 mol) was added, and the mixture was heated to a 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 added dropwise to the above-mentioned dispersion through the dropping funnel over about 30 minutes, and further reacted at the solvent reflux temperature for 3 hours.

Then, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene.
Was added and the mixture was reacted for another 2 hours, and then the reaction solution was cooled to room temperature. To the reaction solution after cooling, 500 ml of toluene
Was added to the reaction mixture, and the resulting precipitate was pressure-filtered 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, remove the solvent under reduced pressure, and add 100 mL of toluene.
Is added and dissolved, and this toluene solution is added with ethanol 100
Dropped into 0 ml.

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

GPC (THF) Mw = 2000.

From the results of Comparative Example 1, it was confirmed that Si-
In the polymerization of dihalosilane monomer having H bond, it was revealed that the effect of adding the copper compound cannot be obtained unless the crown ether as the ether compound is present. In addition, the results of Comparative Example 2 show that the weight average molecular weight of the obtained polysilane is as low as about 2000 and the yield is also low as 7% when the copper compound is not present even when the crown ether is added. ing.

That is, the polysilane of Example 1 synthesized in the presence of an ether compound and a copper compound was the same as Comparative Example 2
The weight-average molecular weight was 2.5 times that of the product obtained in 1., 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 this 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,
A sodium dispersion was prepared by heating to a solvent reflux temperature under an argon atmosphere.

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 added dropwise to the above dispersion through the dropping funnel over about 30 minutes, and further reacted at the solvent reflux temperature for 3 hours.

Then, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene.
Was added and the mixture was reacted for another 2 hours, and then the reaction solution was cooled to room temperature. To the reaction solution after cooling, 500 ml of toluene
Was added to the reaction mixture, and the resulting precipitate was pressure-filtered 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, remove the solvent under reduced pressure, and add 100 mL of toluene.
Is added and dissolved, and this toluene solution is added with ethanol 100
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]

[Chemical formula 46]

Example 3 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 this 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,
A sodium dispersion was prepared by heating to a solvent reflux temperature under an argon atmosphere.

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 added dropwise to the above dispersion through the dropping funnel over about 30 minutes, and further reacted at the solvent reflux temperature for 3 hours.

Then, 10.8 g (0.10 mol) of trimethylchlorosilane dissolved in 20 mL of anhydrous toluene.
Was added and the mixture was reacted for another 2 hours, and then the reaction solution was cooled to room temperature. To the reaction solution after cooling, 500 ml of toluene
Was added to the reaction mixture, and the resulting precipitate was pressure-filtered 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, remove the solvent under reduced pressure, and add 100 mL of toluene.
Is added and dissolved, and this toluene solution is added with ethanol 10
It was dripped into 00 ml.

Finally, the precipitate was filtered and dried in 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]

[Chemical 47]

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

Next, after heating in air at 290 ° C. for 10 minutes, it was heated in a nitrogen atmosphere at 450 ° C. for 1 hour to form a siloxane insulating film (film thickness 0.93 μm). When the dielectric constant of this insulating film was measured, 2.
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 Absorption due to Si-O-Si present was observed at 1133 cm ^-1 , 1038 cm ^-1 .
From these results, the Si-Si bond of the polysilane film and the S
The i-H bond is oxidized to become a Si-O-Si bond,
It was confirmed that a network-shaped 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, in a nitrogen atmosphere, 4
A siloxane-based insulating film was formed by heating at 50 ° C. for 1 hour. When the dielectric constant of this film was measured, 2.
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 exposed to light with a wavelength of 254 nm through a predetermined mask.
After exposure to 00 mJ, a developing solution (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 of Example 5, and then the pattern was observed. As a result, no crack or peeling was observed.

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

Then, 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 methyllithium ether solution (1.4 M) was added dropwise while cooling in an ice-water bath. The resulting mixed solution was stirred at room temperature for 20 hours, then 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 concentrating the solvent, 1.5 g of 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-
1,2,2-trimethyldisilane mixture) 100 g,
Tetrabutylphosphonium chloride (Bu ₄ PC
l) Add 1.0 g and heat to 90 ° C., add 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 to obtain 10 g of yellow solid poly (methylsilane).
The total amount of poly (methylsilane) was dissolved in 100 mL of toluene, and 0.5 equivalent of an ether solution of methyllithium (1.4 M) was added dropwise while cooling with an ice-water bath. After stirring the obtained mixed solution at room temperature for 20 hours, methanol 20m
l was added dropwise to decompose excess methyllithium, the solvent and methanol were removed under reduced pressure, and then extracted with toluene.

After concentrating the solvent, a yellow resinous methylpolysilane was obtained. Reprecipitation with toluene / methanol gave 2.8 g of 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 in 00 g.

[0165]

[Chemical 48]

On a silicon wafer, S with a film thickness of 500 nm is formed.
An iO ₂ film was formed, and the above solution was applied onto the SiO ₂ film and baked to form a polysilane film having a film thickness of 250 nm.

By heating at 240 ° C. for 5 minutes in a nitrogen atmosphere, the polysilane film was crosslinked and made insoluble. Then, a positive chemically amplified resist TDUR-P007 was applied on this polysilane film and baked at 89 ° C. for 120 seconds to form a resist film having a film thickness of 250 nm. KrF
A reduction exposure type stepper using an excimer laser as a light source was used to expose through a mask at an exposure amount of 30 mJ / cm ² , and baked at 98 ° C. for 120 seconds. The resist film after exposure is developed with a TMAH developing solution of 0.21 N to obtain 0.1
A resist pattern of 8 μm line and space was formed. As a result of SEM observation of the cross section of the obtained resist pattern, no wavy shape due to standing waves was observed on the sidewall of the resist pattern. Using the resist pattern as a mask, HBr flow rate 50 sccm, vacuum degree 80 mT
When the polysilane film was etched under the conditions of orr and excitation power of 200 W, a pattern of the polysilane film having vertical sidewalls was formed. It was found that the resist remained on the upper portion and 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, vacuum degree 10 m
The SiO ₂ film was etched under the conditions of Torr and excitation power of 200 W. The polysilane film had sufficient etching resistance, and a SiO ₂ film pattern having vertical sidewalls was obtained.
Further, the remaining polysilane film could be easily peeled off with an organic alkali aqueous solution or a dilute hydrofluoric acid aqueous solution.

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

[0170]

[Chemical 49]

On a silicon wafer, S with a film thickness of 500 nm is formed.
An iO ₂ film was formed, and the above-mentioned solution was applied onto this SiO ₂ film and baked to form a polysilane film having a film thickness of 250 nm.

By heating at 200 ° C. for 5 minutes in a nitrogen atmosphere, the polysilane film was crosslinked and insolubilized. Then, a positive chemically amplified resist TDUR-P007 was applied on this polysilane film and baked at 89 ° C. for 120 seconds to form a resist film having a film thickness of 250 nm. KrF
A reduction exposure type stepper using an excimer laser as a light source was used to expose through a mask at an exposure amount of 30 mJ / cm ² , and baked at 98 ° C. for 120 seconds. The resist film after exposure is developed with a TMAH developing solution of 0.21 N to obtain 0.1
A resist pattern of 8 μm line and space was formed. As a result of SEM observation of the cross section of the obtained resist pattern, no wavy shape due to standing waves was observed on the sidewall of the resist pattern. Using the resist pattern as a mask, HBr flow rate 50 sccm, vacuum degree 80 mT
When the polysilane film was etched under the conditions of orr and excitation power of 200 W, a pattern of the polysilane film having vertical sidewalls was formed. It was found that the resist remained on the upper portion and 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, vacuum degree 10 m
The SiO ₂ film was etched under the conditions of Torr and excitation power of 200 W. The polysilane film had sufficient etching resistance, and a SiO ₂ film pattern having vertical sidewalls was obtained.
Further, the remaining polysilane film could be easily peeled off with an organic alkali aqueous solution or a dilute hydrofluoric acid aqueous solution.

(Example 11) First, 10 g of polysilane (Si-H content 25%) represented by the following chemical formula, 3 g of decaphenylpentasilyl-1,5-diol, BTT.
B 3g, AA-20.1g to cyclohexanone 100
A solution was prepared by dissolving in g.

[0175]

[Chemical 50]

On a silicon wafer, S with a film thickness of 500 nm is formed.
An iO ₂ film was formed, and the above solution was applied onto the SiO ₂ film and baked to form a polysilane film having a film thickness of 250 nm.

The polysilane film was crosslinked and insolubilized by heating at 160 ° C. for 5 minutes in a nitrogen atmosphere. Then, a positive chemically amplified resist TDUR-P007 was applied on this polysilane film and baked at 89 ° C. for 120 seconds to form a resist film having a film thickness of 250 nm. KrF
A reduction exposure type stepper using an excimer laser as a light source was used to expose through a mask at an exposure amount of 30 mJ / cm ² , and baked at 98 ° C. for 120 seconds. The resist film after exposure is developed with a TMAH developing solution of 0.21 normal to obtain 0.18.
A resist pattern of μm line and space was formed. As a result of SEM observation of the cross section of the obtained resist pattern, no wavy shape due to standing waves was observed on the sidewall 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 sidewalls could be formed. It was found that the resist remained on the upper portion and 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, vacuum degree 10 m
The SiO ₂ film was etched under the conditions of Torr and excitation power of 200 W. The polysilane film had sufficient etching resistance, and a SiO ₂ film pattern having vertical sidewalls was obtained.
Further, the remaining polysilane film could be easily peeled off with an organic alkali aqueous solution or a dilute hydrofluoric acid aqueous solution.

From the results of the above examples, it was confirmed that the polysilane of the present invention is preferably used as an insulating film material and a resist material. In addition, the method of the present invention makes it possible to easily synthesize a solid polysilane that can be suitably used for such applications from a halosilane monomer having a highly reactive Si-H bond in a high yield. .

[0180]

As described above in detail, according to the present invention, there is provided 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 polysilane in a high yield.

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

[Brief description of drawings]

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

[Explanation of symbols]

11 ... Silicon substrate 12 ... Insulating film 13 ... Polysilane film 14 ... Resist film

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-189652 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 77/00-77/62

Claims (3)

(57) [Claims] 1. A method for synthesizing a polysilane represented by the following general formula (1) or the following general formula (3), wherein: (In the above general formula, R is a substituted or unsubstituted aliphatic substituent having 6 or less carbon atoms, and a is 0.1 or more and 0.9 or less. R ¹ and R ² may be the same or different. May be a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group or an aromatic hydrocarbon group, respectively.) A copper compound, an ether compound and an alkali metal are added to a solvent and heated to obtain an alkali metal dispersion. A step, a step of dropping a halosilane compound dissolved in a solvent into the dispersion to obtain a reaction product, a step of adding trimethylsilane dissolved in a solvent to the reaction product, and further reacting, And a step of washing the obtained reaction product with ion-exchanged water. 2. The method for synthesizing polysilane according to claim 5, wherein the ether compound is crown ether or a derivative thereof, or an ethylene glycol derivative. 3. A repeating unit having solubility in an organic solvent, a glass transition temperature of −40 ° C. or higher, a repeating unit of 0.1 to 0.9 represented by the general formula (1), and the balance: A polysilane containing a copolymer containing a repeating unit represented by the chemical formula shown in the formula (1)
R is a methyl group, and the repeating unit occupying the rest is
A combination in which R is [1-2] or [1-22], and R is
A trifluoropropyl group, which occupies the rest
A combination in which the unit is [1-8], R is a hexyl group
Yes, the repeating unit occupying the balance is [1-50]
A combination, and R is a trifluorobutyl group,
A combination in which the repeating unit occupying the balance is [1-51]
Excludes omelet. ) . [Chemical 2] (In the 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.
It is 9 or less. ) [Chemical 3] [Chemical 4] [Chemical 5] [Chemical 6] [Chemical 7] [Chemical 8] [Chemical 9] [Chemical 10] [Chemical 11] [Chemical 12] [Chemical 13] [Chemical 14] [Chemical 15] [Chemical 16] [Chemical 17]