JP3069655B2 - Polysilmethylene film forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilmethylene film forming method and a polysilmethylene pattern forming method for easily constructing a polysilmethylene film having heat resistance and poor solubility on a substrate. About.

[0002]

2. Description of the Related Art In recent years, polymers containing silicon in the molecular skeleton have been attracting attention not only as precursors of silicon-based ceramics but also as materials having heat resistance and flame retardancy. I have. Recently, it has been found that polydiphenylsilmethylene emits light when irradiated with an ultraviolet laser, and the development of new applications using the light-emitting action has attracted attention. However, since polysilmethylene is a thermoplastic polymer having high crystallinity, molding similar to ordinary thermoplastic resin is theoretically possible, but molding is performed at a high melting point and a high temperature of about 400 to 500 ° C. Required, and its molding involves considerable difficulty in practice. It is well known that forming a thin film on a substrate is an important technical element when a polymer material is applied to a member of an electric element or an optical element. In general, rather than laminating a film formed by melt molding on a substrate, a polymer is dissolved in a solvent and applied. One of the common disadvantages and advantages of crystalline polymers is that they have very poor solubility in organic solvents. Polysilmethylene,
Particularly, polydiphenylsilmethylene having high heat resistance can be dissolved only at a high temperature using a special compound such as diphenylsulfone as a solvent. Therefore, general coating techniques such as bar coating and spin coating cannot be applied, and there are many problems in using them for electronic devices, optical devices, and the like. In addition, in a dry process such as vacuum deposition which is widely performed for inorganic or metal,
This method cannot be said to be a general method because the polymer chain is cut or deteriorated, and it is difficult to apply the method to polysilmethylene.

On page 99 of the 2nd Symposium on Silicon Polymer Materials for Industrial Science and Technology Research and Development, polysilmethylene is heated to disilacyclobutane or added with copper or a copper compound as a catalyst, melted or ring-opened in solution. It is disclosed that it can be produced by polymerization. Among polysilmethylenes, polydiphenylsilmethylene, which gives particularly high heat resistance, is not dissolved at all in ordinary organic solvents, and is dissolved in diphenyl ether, diphenylsulfone, etc.
Although dissolved at a high temperature of 0 ° C. or more, only a low concentration was obtained. This means that it is practically difficult to apply ordinary coating methods.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a polysilmethylene film on a substrate and a method for forming a pattern of the polysilmethylene on the substrate.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, a disilacyclobutane film is formed on a substrate, and gold, platinum, palladium,
After forming a metal fine particle layer made of a metal selected from the group consisting of copper and silver, the disilacyclobutane film is heated at a temperature lower than the melting point of polysilmethylene obtained from the disilacyclobutane to form the disilacyclobutane. A polysilmethylene film-forming method characterized by subjecting a compound to ring-opening polymerization. According to the present invention, a disilacyclobutane film is formed on a substrate, and gold, platinum, palladium,
A metal fine particle layer made of a metal selected from the group consisting of copper and silver is formed in a pattern, and then heated at a temperature lower than the melting point of polysilmethylene obtained from the disilacyclobutane to cause ring-opening polymerization of the disilacyclobutane. And then removing the disilacyclobutane film on which the metal pattern has not been applied, thereby providing a method for forming a pattern of polysilmethylene.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The disilacyclobutane used in the present invention is a cyclic compound represented by the following general formula (1), and its polymer, polysilmethylene, is a cyclic compound represented by the following general formula (2). It is a polymer having a structural unit. General formula (1):

Embedded image General formula (2):

Embedded image

In the above general formulas (1) and (2), R
¹ and R ² are the same or different aryl groups. This aryl group may be a substituted aryl group or an unsubstituted aryl group. Specifically, a phenyl group, a tolyl group, a naphthyl group and the like are preferable.

The polysilmethylene having a repeating structural unit represented by the general formula (2) has high heat resistance and emits light by irradiation with an ultraviolet laser. The aromatic group-substituted disilacyclobutane used as the raw material can be synthesized, for example, by the method reported by Auner et al. (N. Auner, & J. Grobe, J. Organ).
ometal. Chem. , 188, 151 (198
0)). That is, it can be synthesized by dimerizing chloromethyldiphenylsilane in the presence of metallic magnesium. Incidentally, the melting point of 1,1,3,3-tetraphenyl-1,3-disilacyclobutane is 133 to 137.
° C. The substituents on the silicon of disilacyclobutane need not necessarily be of the same aromatic group. Since the crystallinity or physical properties of the polymer are changed by changing the type of the aromatic group, a substituent on silicon is appropriately selected according to the intended use.

According to the present invention, a disilacyclobutane film is formed on a substrate, a predetermined metal fine particle layer is formed thereon, and this is heated to obtain polysilmethylene by ring-opening polymerization. The disilacyclobutane film is preferably formed by an evaporation method. In this case, the disilacyclobutane is heated and vaporized under reduced pressure and deposited on the substrate.
In this method, the substrate surface may be heated to a temperature at which the ring-opening reaction of disilacyclobutane does not occur in order to increase the deposition rate. The vapor deposition method includes a sputtering method, a CVD method, a vacuum vapor deposition method, and the like. Further, as another method of forming a disilacyclobutane film on the substrate, an organic solvent solution of disilacyclobutane is applied on the substrate by a spin coating method, a bar coating method, an immersion method, or the like,
Drying method is mentioned. Examples of the organic solvent for dissolving disilacyclobutane include aromatic hydrocarbons such as toluene and xylene; and halogenated hydrocarbons such as methylene chloride, chloroform and ethylene chloride. As the drying atmosphere, air, an inert gas, a vacuum atmosphere, or the like is used. The thickness of the disilacyclobutane film is not important and is set according to the purpose and use.

As the substrate, those made of various materials such as silicon wafers, metals, ceramics, plastics and the like are used. The surface shape of the substrate can be various shapes such as a flat shape, a curved shape, and a spherical shape.

A metal fine particle layer is formed on the disilacyclobutane film formed on the substrate as described above.
For this purpose, an evaporation method, a sputtering method, a laser ablation method, or the like can be used. The metal used is selected from gold, platinum, palladium, copper and silver.
One kind of metal or a combination of two or more kinds of metals may be used.

Next, the disilacyclobutane film formed on the substrate as described above and having the fine metal particle layer formed thereon as the surface layer is heated to a temperature lower than the melting point of polysilmethylene obtained from the disilacyclobutane. Heat with. By this heating, the metal fine particles diffuse into the disilacyclobutane film to induce ring-opening polymerization of the disilacyclobutane. Thus, the disilacyclobutane film on the substrate is converted into a polysilmethylene film. The thickness of the metal fine particle layer is not important as long as the metal fine particles can diffuse into the disilacyclobutane film, and the metal fine particle layer is not a continuous phase. The heating temperature of the disilacyclobutane film may be a temperature at which the disilacyclobutane undergoes ring-opening polymerization,
Although the temperature may be lower than the melting point, the temperature is preferably higher than the melting point in order to quickly form a polymer film having a stable structure from which the internal stress of the obtained polymer film has been removed. Further, at a temperature higher than the melting point of the obtained polymer film, the polymer film is undesirably deformed by flowing. Therefore, the heating temperature is 30 to 5 times lower than the melting point of the disilacyclobutane.
0 ° C. lower than the melting point of the polymer,
Preferably, the temperature is higher than the melting point of disilacyclobutane and lower than the melting point of the polymer (polysilmethylene). When the disilacyclobutane is tetraphenyldisilacyclobutane, it is preferable to use a temperature in the range of 137 ° C, which is the melting point, to 350 ° C, which is the melting point of the polymer (polydiphenylsilmethylene). Further, from the viewpoint of the polymerization rate, it is preferable to use a high temperature. In particular, since the temperature at which tetraphenyldisilacyclobutane completely undergoes a phase transition to polydiphenylsilmethylene is about 210 ° C., it is preferable to use a high temperature.
It is more preferred to use a temperature of 0-300C. The heating atmosphere is not particularly limited, and may be an inert gas atmosphere, a vacuum atmosphere, an air atmosphere, or the like.

The above-mentioned polymerization of disilacyclobutane by heating indicates that the polymerization is proceeding by a mechanism not inhibited by oxygen. The fact that ring-opening polymerization of disilacyclobutane occurs by heating and polysilmethylene is formed can be confirmed by observing its infrared absorption spectrum. That is, when measuring the infrared absorption spectrum, the broad peaks 900cm ^-1 ~1000cm ^-1 derived from polysilsesquioxane methylene structure, to appear on behalf of the sharp peak around characteristic of 950 cm ^-1 to disilacyclobutane From this, it is easily confirmed that ring-opening polymerization of disilacyclobutane was performed.

It has been confirmed that the fine metal particle layer disappears from the surface of the polysilmethylene film thus obtained. That is, the metal fine particles diffuse into the disilacyclobutane during the polymerization step by heating, and as a result, are dispersed in the polymerized film. When the surface is observed using ESCA, the peak intensity indicating a metal atom is extremely weak, but it is recognized that the metal is distributed inside the film as the film is etched.

Incidentally, even if a metal fine particle film used in the present invention is previously formed on a substrate, and a tetraphenyldisilacyclobutane film is formed thereon and then treated under the same heating conditions, the object can be achieved. Substantially no polydiphenylsilmethylene is formed. Further, the tetraphenyldisilacyclobutane film having no metal fine particle layer does not polymerize under the same conditions. The polymerization mechanism of tetraphenyldisilacyclobutane in the present invention is not known at present, but metal fine particles diffuse into the tetraphenyldisilacyclobutane film,
It is believed that the polymerization proceeds by a mechanism that is not affected by oxygen.

In the present invention, a polysilmethylene pattern can be easily formed by forming a metal fine particle layer in a pattern on a disilacyclobutane film and heating it in the same manner as described above. Since the disilacyclobutane film in the portion where the metal fine particle layer is not applied is not polymerized only by the above-described temperature treatment, the disilacyclobutane film is dissolved and removed with a solvent that dissolves disilacyclobutane, or the vapor pressure of disilacyclobutane is 190 ° C. Is about 10 ⁻³ mmHg, it can be removed by heating in a vacuum to evaporate or sublimate.

The polydiphenylsilmethylene formed on the substrate as described above emits pale light when irradiated with KrF laser light. That is, similarly to ordinary polydiphenylsilmethylene, when a laser having a frequency of 5 Hz is irradiated for 1 second at an output of 0.01 W / cm ² , broad emission having an emission maximum near 550 nm is observed, and attenuation of emission is also observed. Similarly, after 0.5 seconds, the initial luminescence intensity is about 50%.
%, And a luminescence behavior not different from that of the polydiphenylsilmethylene simple substance obtained by a conventionally known method was confirmed.

The surface roughness of the polysilmethylene film can be adjusted by the type of the fine metal particle layer formed on the disilacyclobutane film. That is, when the thickness of the metal fine particle layer is constant, the surface roughness is 500 nm for copper, 100 to 200 nm for gold, and 10 nm or less for platinum.
When detecting the light emission by irradiating an ultraviolet laser, when the surface roughness is small, there is little scattering on the surface, so that there is an effect that the emission image becomes clear. The surface roughness is measured by AFM. The emission of the polysilmethylene film by ultraviolet laser irradiation is described in detail in JP-A-9-208945.

[0019]

According to the present invention, it is possible to form a polysilmethylene film including the formation of a thin film on a substrate, and it is easy to apply the present invention to a laser light detecting element utilizing a light emission phenomenon by laser irradiation. Furthermore, by using polysilmethylene as a silicon carbide precursor, a silicon carbide film can be formed by a method other than the gas phase method, and a new silicon carbide film formation method is suggested.

[0020]

Next, the present invention will be described in more detail by way of examples.

Reference Example 1 Synthesis of 1,1,3,3-tetraphenyl-1,3-disilacyclobutane ([Ph ₂ SiCH ₂ ] ₂ ) Chloromethyldiphenylchlorosilane was prepared from chloromethyltrichlorosilane and phenylmagnesium chloride. Obtained according to a conventional method. This chloromethyldiphenylchlorosilane (20 g) was dropped into 100 ml of tetrahydrofuran containing 2.5 g of magnesium shavings over 2 hours. After completion of the dropwise addition, the mixture was refluxed for 5 hours while stirring, and then 80 ml of toluene was added.
Water was added. The organic phase was separated, washed with water and dried over magnesium sulfate. The solvent was distilled off from the organic phase under reduced pressure using a rotary evaporator to obtain 14 g (almost quantitative) of crude crystals of tetraphenyldisilacyclobutane. The crude crystals were recrystallized from ether to give a melting point of 133-137.
Crystals having a temperature of 10 ° C (DSC measurement, heating rate 10 ° C / min) were obtained.

Example 1 Recrystallized 1,1,3,3-tetraphenyl-1,3-
After further sublimating and purifying the disilacyclobutane, a film having a thickness of about 4 μm is formed on the silicone wafer by vacuum deposition at 10 ⁻³ Torr, and copper is sputtered thereon with air plasma of 10 ⁻³ Torr. A copper fine particle layer of about 4 nm was formed. This is taken out of the vacuum chamber and 280
Heated in air in a heating furnace heated to 10 ° C for 10 minutes.
The infrared absorption spectrum of the formed film was measured. The absorption band at 937 cm ^-1 based on the C-Si bond of the 4-membered ring structure disappears, and 1074 and 105 due to the polysilmethylene skeleton.
The appearance of an absorption band at 1,779 cm ⁻¹ confirmed that ring opening polymerization of tetraphenyldisilacyclobutane had occurred. In addition, it was confirmed that polydiphenylsilmethylene was formed, since the infrared absorption spectrum was the same as that of polydiphenylsilmethylene obtained by thermal polymerization.

Example 2 Gold was deposited on a 1,1,3,3-tetraphenyl-1,3-disilacyclobutane film formed in the same manner as in Example 1 by 10 ^-3 T.
A gold particle layer of about 3 nm was formed by sputtering with an air plasma at orr. This was heated at 280 ° C. for 10 minutes in argon. The infrared absorption spectrum of the obtained polymer film was measured. The same spectrum as in Example 1 was observed, and the formation of polydiphenylsilmethylene was confirmed.

Example 3 An experiment was conducted in the same manner as in Example 1 except that platinum was deposited.
A polymer film was obtained. The infrared absorption spectrum was measured.
The same spectrum as in Example 1 and Example 2 was observed, and formation of polydiphenylsilmethylene was confirmed.

Example 4 A gold fine particle layer was formed through a mask under the same conditions as in Example 2. When this was heated in a vacuum at 250 ° C. for 15 minutes, the portion of the film where no metal pattern was applied sublimated during heating, and a polydiphenylsilmethylene pattern corresponding to the metal pattern was formed on the substrate. In the infrared absorption spectrum of the portion covered by the mask,
None of the infrared absorption spectra of 3-tetraphenyl-1,3-disilacyclobutane and polydiphenylsilmethylene were observed, and the portion not covered by the mask (the portion on which the metal pattern was applied) was the same as in Example 2 above. The same infrared absorption spectrum as in the case of was observed. To this
Using an rF laser (AQX-150, manufactured by MPB),
When a 248 nm light was irradiated with a 5 Hz pulse at an output of 0.11 W / cm ² for 1 second, light emission was observed from 400 to 600 nm. This was the same light emission as that of polydiphenylsilmethylene generated by thermal polymerization.

Example 5 In Example 1, platinum / palladium = 80/20
The experiment was performed in exactly the same manner except that an alloy having a composition (weight ratio) was sputtered. When the infrared absorption spectrum of the obtained polymer film was measured, the same spectrum as that of polydiphenylsilmethylene was observed, and it was confirmed that polydiphenylsilmethylene was generated.

Example 6 The surface roughness of the polydiphenylsilmethylene films formed in Examples 1, 2 and 3 was measured by AFM. The surface roughness is approximately 430 nm for copper, 135 nm for gold,
For platinum, it was 2 nm. The surface roughness varied depending on the metal sputtered on the tetraphenyldisilacyclobutane film. The surface roughness was measured using a SPA300 manufactured by Seiko Instruments Inc.

Comparative Example 1 A copper fine particle layer was formed on a silicon substrate, and 1,1,3,3-tetraphenyl-1,3-disilacyclobutane was deposited thereon. But heated,
No polydiphenylsilmethylene was formed.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Suzuki 2-17-1, Tsukikan East, Toyohira-ku, Sapporo-city, Hokkaido Inside the Institute of Industrial Technology, Hokkaido Institute of Industrial Technology (72) Inventor Yoshinori Nakata Tsukikan, Toyohira-ku, Sapporo, Hokkaido Higashi 2-Jo 17-2-1, Hokkaido Institute of Industrial Technology, Hokkaido Institute of Industrial Technology (72) Inventor Hideaki Nagai Hokkaido Sapporo City, Toyohira-ku, Tsukikan Higashi 2-Jo 17-2-1, Hokkaido Institute of Technology, Hokkaido Institute of Industrial Technology (72) Inventor Takeshi Okutani 2-1-1-17 Tsukikan-Higashi, Toyohira-ku, Sapporo-city, Hokkaido In-house Hokkaido Institute of Industrial Technology (72) Inventor Nobuo Kushibiki 2-21-10-305, Tsujido Motomachi, Fujisawa-shi, Kanagawa-ken (72) Inventor Masashi Murakami 389-3 Ojiri, Hadano-shi, Kanagawa Prefecture (72) Inventor ▲ Taku ▼ ya 286-10 Chimura, Hadano-shi, Kanagawa Examiner Takayuki Harada (56 References JP-A-8-109266 (JP, A) JP-A-7-196807 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08G 77/60 G08J 5/18

Claims (3)

(57) [Claims] 1. A disilacyclobutane film is formed on a substrate, and a metal fine particle layer made of a metal selected from the group consisting of gold, platinum, palladium, copper and silver is formed on the film. A method for forming a polysilmethylene film, comprising heating a cyclobutane film at a temperature lower than the melting point of polysilmethylene obtained from the disilacyclobutane to cause ring-opening polymerization of the disilacyclobutane. 2. The method according to claim 1, wherein the metal forming the metal particle layer is gold, platinum,
Selected from the group consisting of palladium, copper and silver;
The method for forming a polysilmethylene according to claim 1, wherein the surface roughness is adjusted within a range of 5 to 1000 nm. 3. A disilacyclobutane film is formed on a substrate, and a metal fine particle layer made of a metal selected from the group consisting of gold, platinum, palladium, copper and silver is formed on the film in a pattern. Heating the polysilmethylene obtained from the disilacyclobutane at a temperature lower than the melting point of the disilacyclobutane to cause ring-opening polymerization of the disilacyclobutane, and then removing the disilacyclobutane film on which the metal pattern is not applied. A method for forming a lmethylene pattern.