JPH04264132A - Hydrophenylpolysilane and its production - Google Patents

Abstract

PURPOSE:To prepare hydrophenylpolysilane which has a specific structural formula, shows an improved film-forming capability and an improved adhesion to a substrate, and is useful for a photoresist, etc., by condensing dichlorophenylsilane in the presence of metallic sodium. CONSTITUTION:Dichlorophenylsilane is condensed in the presence of metallic sodium to give hydrophenylpolysilane of the formula (wherein (n) is a mean degree of polymn.).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to photoresists, optical waveguide materials, silicon carbide precursors, semiconductors, electrophotographic photoreceptors, and nonlinear optical materials, which are not available in conventional polymeric materials with carbon skeletons. This research concerns a soluble hydrophenylpolysilane polymer with a silicone backbone, which is a new type of functional material with unique characteristics.

0002

[Prior Art] In recent years, soluble organic polysilanes, which are polymers with a silicon skeleton, have been used as photoresists, silicon carbide precursors, semiconductors, electrophotographic photoreceptors, nonlinear optical materials, and optical waveguides. It is attracting a lot of attention as a new type of functional material with unique characteristics not found in conventional polymer materials. One of the reasons why organic polysilanes have attracted interest is that they dissolve in organic solvents and can be easily processed into fibers and thin films. However, most of the organic polysilanes known so far are Si
Two organic substituents were introduced into (SiR1 R2) (
It is a chemical structure in which R1 and R2 are organic substituents) as repeating units. Therefore, for example, the sensitivity is not sufficient for processing thin films of several microns in thickness such as photoresists and optical waveguides using photochemical cleavage reactions and crosslinking reactions, and Si
Because of self-absorption due to the strong ultraviolet absorption band derived from the -Si bond, the film thickness could not be increased, and the properties were not satisfactory compared to conventional carbon-based polymer materials. In addition, from a practical point of view, two organic substituents were introduced to Si (SiR1 R2
)-type organic polysilanes lacked adhesion to glass and silicon substrates having a chemical structure in which (R1 and R2 are organic substituents) are repeating units. In order to achieve high sensitivity, it is necessary to use a polymer that has chemically active SiH bonds and has not too strong absorption of irradiated ultraviolet rays. Furthermore, in order to improve adhesion, it is effective to introduce polar SiH bonds. Although various low-molecular substances containing SiH bonds are known, their polymers are hardly known. There are only a few reports regarding hydrophenylpolysilanes and hydroalkylpolysilanes. However, reports suggest that the molecular weight obtained is up to 150
It lacks thin film forming ability due to its low molecular weight of less than 0, and is not of interest from a practical standpoint compared to high molecular weight organic polysilanes whose constituent units are (SiR1 R2), which usually have a molecular weight of at least 10,000 or more. . Examples of reported synthesis of organic polysilanes having SiH bonds are shown below. (a)C. Aitkin, J. F. Harrod, U. S. Gill (C. Aitkin, J. F. Harrod
, U. S. Gill), Canadian Journal of Chemistry (Can. J.
Chem. ), vol. 65, p. 1804 (1987
): 1 ml of phenylsilane was reacted with 10 mg of dimethyltitanocene in 1 ml of toluene at room temperature for 7 days to obtain hydrophenylpolysilane with a number average degree of polymerization of 8 to 13. (a) T. Nakano, H. Nakamura, Y. Nagai (T.
Nakano, H. Nakamura, Y. Nag
ai), Chemistry Letters (Chem.
Lett. ), p. 83 (1989): Phenylsilane and diphenyltitanocene were reacted to obtain hydrophenylpolysilane having a weight average degree of polymerization of 7 to 9.

0003

However, these methods using titanocene catalysts require separation of colored reaction by-products containing titanocene in a column in order to isolate the produced hydrophenylpolysilane. The disadvantages are that the obtained molecular weight is low, the ability to form a thin film is insufficient, and the reaction takes a long time. The objects of the present invention are a highly sensitive photoresist, an optical waveguide material with low waveguide loss, a semiconductor capable of p/n type doping, a silicon carbide precursor with high conversion efficiency, a highly sensitive electrophotographic photoreceptor, and a high efficiency The object of the present invention is to provide a high molecular weight hydrophenylpolysilane having SiH bonds and having good thin film forming ability and adhesion to a substrate, which is expected to be used as a nonlinear optical material.

0004

[Means for Solving the Problems] To summarize the present invention, the first invention of the present invention relates to hydrophenylpolysilane, which has the following structural formula (Formula 1):

It is characterized by being represented by the following formula (n represents the weight average degree of polymerization). A second invention of the present invention relates to a method for producing hydrophenylpolysilane represented by the above structural formula (Chemical formula 1), and is characterized in that dichlorophenylsilane is condensed with metallic sodium.

In order to realize the high molecular weight hydrophenylpolysilane, the present invention uses the above-mentioned C.I. In contrast to the method of Aitkin et al., in which hydrophenylsilane is obtained by dehydrogenation polymerization of phenylsilane using dimethyltitanocene as a catalyst, a method of condensing the corresponding dichlorosilane with metallic Na was applied.

Examples of the target compound of the present invention include hydrophenylpolysilane and monosilane, which are characterized by having an n value of 20 or more as determined by gel permeation chromatography using monodisperse polystyrene as a standard. The value of n is 20 or more as determined by gel permeation chromatography based on dispersed polystyrene, and approximately -60 in 29Si-FTNMR (CP-MAS method).
Hydrophenylpolysilane is characterized by having one broad peak per ppm, and the value of n is 20 or more as determined by gel permeation chromatography based on monodisperse polystyrene, and 29Si-FT
Si-H2 has one broad peak at about -60 ppm in NMR (CP-MAS method) and is determined by FT-IR method.
Bending vibration δ (Si-H) and Si-H stretching vibration ν (Si-
Examples include hydrophenylpolysilane, which is characterized by a relative absorption intensity ratio with H) of 0.45 or less.

[0007]

[Examples] The present invention will be explained in more detail below with reference to Examples and Application Examples, but the present invention is not limited thereto. Note that all reaction operations and purification operations were performed under an argon gas atmosphere and with indoor light cut off.

Example 1 After thoroughly dehydrating and degassing the inside of the reaction vessel and purging with argon gas, 6.5 g of dichlorophenylsilane and 30 m of toluene were added.
1 into the flask. At an oil bath temperature of 110° C., 8.5 g of a metal sodium dispersion (toluene 30%) was added all at once, and the reaction was further continued for about 5 minutes after the addition. The reaction mixture solution was filtered under pressure, and the filtrate was added to degassed cold isopropyl alcohol. The resulting white precipitate was collected using a centrifuge, and 6
It was vacuum dried at 0°C. The yield was 1.02 g, which was 26.2% based on dichlorodiphenylsilane. The weight average degree of polymerization determined by gel permeation chromatography using monodisperse polystyrene as a standard is 42.
5. Dispersity (=weight average degree of polymerization/number average degree of polymerization) is 2.
A monomodal polymer of 54 was obtained, with a degree of polymerization ranging from 280 to 1.
It ranged from 2. The obtained hydrophenylpolysilane could be easily formed into a thin film by spin coating or solvent casting, had good adhesion to the glass substrate, and did not peel off with a little force. Therefore, the advantage of using hydrophenylpolysilane with a higher molecular weight than before has been realized.

FIG. 1 shows the FT-IR absorption spectrum of a hydrophenylpolysilane thin film produced by the solvent casting method. The attribution is as follows. Aromatic C-H stretching vibration 3
066, 3048, 3010 cm-1, Si-H stretching vibration 2106 cm-1, aromatic C=C stretching vibration 1594,
1492, 1428 cm-1, Si-H2 bending vibration 90
6 cm-1, Si-C stretching vibration 1100 cm-1, monosubstituted benzene ring absorption 734, 696 cm-1, Si-S
iStretching vibration 490cm-1. Si-H stretching vibration ν (Si-H) at 2106 cm-1 based on terminal Si-H2 bond and Si-H bond and terminal Si-
Si-H2 bending vibration based on H2 bond (δSi-H
) was observed, and their relative absorption intensity ratio I (δSi-H
)/I(νSi-H) was 0.40. Also, Si-
Almost no absorption near 1000 to 1100 cm-1 due to O-Si is observed. Almost no C-H stretching vibration around 2900 cm-1 due to aliphatic hydrocarbon groups is observed. This indicates that the obtained phenylpolysilane has almost no siloxane structure, and also hardly reacts with toluene, which is a reaction solvent, or isopropyl alcohol, which is a reprecipitation solvent. In FIG. 1, the horizontal axis represents wave number (cm-1), the vertical axis represents absorbance, and the substrate is KBr.

FIG. 2 shows 29Si-FTNMR (CP-MAS method) of the obtained hydrophenylpolysilane solid. It shows only one broad peak at about -60 ppm, and no other peaks are observed. This means that the obtained hydrophenylpolysilane has a linear skeleton and does not have a three-dimensional crosslinked structure. In addition, in FIG. 2, the unit of the horizontal axis is ppm.

UV of the obtained hydrophenylpolysilane
The absorption spectrum is shown in FIG. 3 (solvent: tetrahydrofuran, room temperature). 3 as found in ordinary organic polysilanes.
Although strong characteristic absorption is not observed in the band from 00 to 400 nm, there is an absorption coefficient of about 4000 (unit: Si) near about 270 nm.
Absorption derived from the Si-Si chain of monomer)-1(1)-1 is observed.

Example 2 After the inside of the reaction vessel was sufficiently dehydrated and degassed and replaced with argon gas, 30 ml of toluene and 2.6 g of small pieces of metallic sodium were added.
into the flask. At an oil bath temperature of 110° C., 6.5 g of dichlorophenylsilane was added and the reaction was further continued for about 30 minutes. The reaction mixture solution was filtered under pressure, and the filtrate was added to degassed cold ethyl alcohol. The resulting white precipitate was collected using a centrifuge and vacuum dried at 60°C. Yield is 0.65
It was g. A monomodal polymer with a weight average degree of polymerization of 20 and a degree of dispersion (=weight average degree of polymerization/number average degree of polymerization) of 2.88 determined by gel permeation chromatography using monodisperse polystyrene as a standard was obtained. It was done. The obtained hydrophenylpolysilane could be easily formed into a thin film by spin coating or solvent casting. The relative absorption intensity ratio I(δSi-H)/I(νSi-H) was 0.44.

Comparative Example 1 R. H. Cragg, R. G. Jones, A. C. Swain, S. J. Webb (R.H. Cragg,
R. G. Jones, A. C. Swain
, S. J. Webb), Journal of
Chemical Society (J.Chem.So
c. ), p. 1147 (1990), we attempted to apply a low-temperature synthesis method of organic polysilanes using crown ether to the synthesis of hydrophenylpolysilane. After thoroughly dehydrating and degassing the inside of the reaction vessel and purging with argon gas, 5.3 g of dichlorophenylsilane, 50 ml of ethyl ether, and 1.0 g of 15-5 crown ether were added.
into the flask. At an oil bath temperature of 40° C., 6.5 g of a metal sodium dispersion (toluene 30%) was quickly added, and the reaction was further continued for about 5 hours after the addition. The reaction mixture solution was filtered under pressure, and the filtrate was added to methyl alcohol. A very small amount of white precipitate was collected using a centrifuge, vacuum dried at 60°C, and the degree of polymerization was determined by gel permeation chromatography. As a result, a hydrophenyl condensate having an extremely low weight average degree of polymerization of 3 to 4 was obtained.

Application Example 1 The obtained hydrophenylpolysilane has a molecular weight of 250 to 35
Since it has a wide absorption range over 0 nm, it is expected to facilitate microfabrication using an ultraviolet light source filled with xenon, deuterium, mercury, etc., or a powerful light source such as a nitrogen laser or excimer laser. In fact, when the obtained hydrophenylpolysilane thin film (thickness approximately 0.3 microns) is irradiated with a mercury lamp (output 6W) with a wavelength of 254 nm, it becomes completely insolubilized in nonpolar solvents such as heptane in about 10 minutes, and the so-called Shows negative characteristics. Also,
Hydrophenylpolysilane thick film (approximately 10 microns thick)
When irradiated with a mercury lamp with a wavelength of 365 nm (output 6 W), insolubilization occurred completely in about 15 minutes.

The photoreaction of the hydrophenylpolysilane thin film was monitored in air at room temperature using ultraviolet absorption spectroscopy and FT-IR. Figure 4 shows the change over time in the UV absorption spectrum of the hydrophenylpolysilane thin film synthesized in Example 1 due to ultraviolet irradiation, and Figure 5 shows the change over time in the FT-IR absorption spectrum (wavelength: 254 nm, output 6 W, in air). ,
room temperature). From the ultraviolet absorption spectrum, as the light irradiation time increased, the broad absorption band originating from the Si-Si chain spanning from 235 to 350 nm completely disappeared, leaving only a weak absorption band from around 250 to 300 nm originating from the presence of the phenyl group. From FT-IR, the Si-H stretching vibration around 2100 cm derived from hydrophenylpolysilane and the stretching vibration derived from the Si-Si bond around 490 cm disappeared, and the stretching vibration at 2170 cm derived from the hydrophenylpolysiloxane structure disappeared. Si-H stretching vibration near -1, 10
76, stretching vibration originating from the Si-O-Si bond near 1060 cm-1, and 1718 cm- originating from the ketone structure.
A broad absorption near 1 and a broad absorption at 3400 cm −1 derived from the structure of the Si-OH bond aggregate appeared. Based on these facts, the hydrophenylpolysilane film can be rapidly converted from Si-Si bonds in the main chain to Si-O by light irradiation.
-Si bonds, and some Si-H bonds become Si-
It is thought that the Si--OH is further cross-linked as a Si--O--Si bond, thereby becoming insolubilized. Conventionally known organic polysilanes exhibit so-called positive behavior because the Si--Si bonds in the main chain change to Si--O--Si bonds upon irradiation with light, improving their solubility in solvents. The high molecular weight hydrophenylpolysilane shown in the present invention, on the contrary, exhibits negative-tone properties.

[0016]

Effects of the Invention As explained above, by dechlorinating and polymerizing hydrophenyldichlorosilane with metallic sodium, Si-
Hydrophenylpolysilane having H-bonds and excellent thin film forming ability and substrate adhesion can be provided in an extremely short time. The high molecular weight hydrophenylpolysilane obtained in the present invention can be used as a highly sensitive photoresist, an optical waveguide material with low waveguide loss, a semiconductor capable of controlling p/n type, a silicon carbide precursor with high conversion efficiency, and a highly sensitive photoresist. It is expected to be applied in a wide range of fields as an electrophotographic photoreceptor and a highly efficient nonlinear optical material. Especially at wavelengths of 300 to 400 nm, Si
Since it has a weak absorption band based on -Si chains, it is suitable as a negative-tone material for microfabrication and for patterning thick polymer films that do not require a sensitizer.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the FT-IR absorption spectrum of hydrophenylpolysilane synthesized in Example 1 of the present invention (substrate: KBr).

FIG. 2 is a diagram showing a Si-FTNMR spectrum of hydrophenylpolysilane synthesized in Example 1 of the present invention (CP-MAS method).

FIG. 3 is a diagram showing the UV absorption spectrum of hydrophenylpolysilane synthesized in Example 1 of the present invention (solvent: tetrahydrofuran, room temperature).

FIG. 4 is a diagram showing the change over time in the UV absorption spectrum of the hydrophenylpolysilane thin film synthesized in Example 1 of the present invention due to ultraviolet irradiation (wavelength: 254 nm, output 6
W, in air, room temperature).

FIG. 5 is a diagram showing the change over time in the FT-IR absorption spectrum of the hydrophenylpolysilane thin film synthesized in Example 1 of the present invention due to ultraviolet irradiation (wavelength: 254 nm,
Output 6W, in air, room temperature).

Claims (2)

[Claims] 1. A hydrophenylpolysilane represented by the following structural formula (Chemical formula 1): [Chemical formula 1] (n represents a weight average degree of polymerization). 2. The method for producing hydrophenylpolysilane represented by the structural formula (Chemical formula 1) according to claim 1, characterized in that dichlorophenylsilane is condensed with metallic sodium.