JP3539234B2 - Polysilane composition for forming metal pattern coating and metal pattern forming method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polysilane composition for forming a coating film used for forming a metal pattern and a metal pattern forming method using the same.
[0002]
Problems to be solved by the prior art and the invention
A variety of applications are performed on substrates on which metal patterns are formed, such as printed wiring boards and comb-shaped electrode substrates for sensors. Such a method of forming a metal on a substrate is performed by a wet method typified by a vapor phase method such as a CVD method or a plating method, but patterning is usually performed by using a resist material, and exposing and developing. It is performed using complicated steps including steps.
[0003]
To solve such complications, Whiteside et al. Have already proposed a technique for forming a new metal pattern. This involves immersing a rubber material having irregularities in a dispersion of colloidal palladium, and then pressing the rubber material against a substrate to transfer the colloidal palladium to the substrate, and immersing the substrate in an electroless plating solution. A metal pattern is formed by depositing a metal only in a certain portion of the palladium colloid (Langmuir 1996, 12, 1375-1380).
However, in this method, the palladium colloid is very unstable, and a surfactant such as tetraammonium halide is added to stabilize the colloid. In this case, there is a drawback that coagulation / precipitation occurs, a uniform metal pattern cannot be obtained, and sufficient adhesion between the substrate and the metal cannot be obtained.
[0004]
Polysilane, on the other hand, is a very interesting polymer because of its metallic properties compared to carbon, its ultraviolet absorption properties due to its unique electron delocalization, high heat resistance and flexibility, and good thin film formation properties. For the purpose of developing a photoresist capable of forming an extremely fine pattern with high precision, researches using polysilane have been actively conducted (for example, JP-A-6-291273 and JP-A-7-114188). In addition, the present inventors have found a pattern forming method utilizing the fact that when a polysilane comes in contact with a solution of a palladium salt, a palladium colloid can be generated, and when irradiated with ultraviolet light, it can be converted into a polysiloxane. It is reported that a metal pattern can be formed by combining such characteristics of a polysilane thin film and electroless plating using a palladium colloid as a catalyst (Japanese Patent Application Laid-Open No. 10-326957). However, a step of performing light irradiation and exposure was necessary.
[0005]
The present invention overcomes these drawbacks and provides a method of forming a metal pattern on a substrate by a simple process such as a stamping method, an ink-jet method, and a flat-plate printing method without performing light irradiation and exposure. It is an object of the present invention to provide a polysilane composition for forming a film for a metal pattern used for the above.
[0006]
Means for Solving the Problems and Embodiments of the Invention
The present inventors have conducted intensive studies to achieve the above object, and as a result, a coating obtained by mixing a polyfunctional silane and a carbon functional silane (CF silane) captures a palladium salt very easily. The electroplating film can be formed reliably and with good adhesion, and the film strength of the film is high. Furthermore, by using this polysilane composition, the pattern of polysilane can be easily formed by a stamping method, an ink jet method, and a flat printing method. A film can be formed, and a catalytic metal nucleus such as palladium is formed on this pattern film and immersed in an electroless plating solution to form a metal pattern by an inexpensive and simple process without using exposure and development processes. The inventors have found that they can do this, and have accomplished the present invention.
[0007]
Therefore, the present invention provides a pattern coating of a polysilane composition on a substrate by a stamping method, an ink jet method or a lithographic printing method, depositing a catalytic metal nucleus of electroless plating on the pattern coating, and then applying an electroless plating solution. The polysilane composition used in the metal pattern forming method for immersing the polysilane in an electroless plating film on the pattern coating, wherein the polysilane and the following formula (2)
_{Y- (CH 2) n -SiR a} (OR) 3-a (2)
(In the formula, Y is an amino functional group, R is a substituted or unsubstituted monovalent hydrocarbon group, n is an integer of 0 to 3, and a is 0 or 1.)
A polysilane composition for forming a metal pattern film, comprising a carbon functional silane represented by and a solvent dissolving the same, and a stamping method, an inkjet method, or a lithographic printing method using the polysilane composition. After forming a pattern coating of the polysilane composition on the substrate by the above, a catalytic metal nucleus for electroless plating is adhered on the pattern coating, and then immersed in an electroless plating solution to perform electroless plating on the pattern coating. Provided is a metal pattern forming method characterized by depositing a film.
[0008]
Hereinafter, the present invention will be described in more detail. The polysilane composition for forming a film for a metal pattern according to the present invention contains polysilane, carbon functional silane (CF silane), and a solvent dissolving them.
[0009]
Here, the polysilane may be any as long as it can form a film, and in particular, a material represented by the following formula (1) is preferably used.
[0010]
(R ¹ _m R ² _n X _p Si) _q (1)
(Wherein, R ¹ and R ² are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, X is R ¹ or an alkoxy group or a halogen atom, m is 0.1 ≦ m ≦ 2, and n is 0 ≦ n ≦ 1, p is 0 ≦ p ≦ 0.5, and a number satisfying 1 ≦ m + n + p ≦ 2.5, and q is an integer of 4 ≦ q ≦ 100,000.)
Examples of the monovalent hydrocarbon group of R ¹ and R ² include a substituted or unsubstituted aliphatic hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group. As the aliphatic or alicyclic hydrocarbon group, those having 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclopentyl group, Examples thereof include an alkyl group such as a cyclohexyl group, and a cycloalkyl group. The aromatic hydrocarbon group preferably has 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms. Examples thereof include an aryl group such as a phenyl group, a tolyl group, a xylyl group and a naphthyl group, a benzyl group, and a phenylethyl group. Aralkyl groups and the like. Further, as the substituted hydrocarbon group, part or all of the hydrogen atoms of the unsubstituted aliphatic hydrocarbon group, alicyclic hydrocarbon group or aromatic hydrocarbon group may be a halogen atom, an alkoxy group, an amino group, an amino group. Those substituted with an alkyl group and the like, for example, a monofluoromethyl group, a trifluoromethyl group, a p-dimethylaminophenyl group, an m-dimethylaminophenyl group and the like can be mentioned.
[0011]
X is the same group as R ¹ , an alkoxy group or a halogen atom. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group and an ethoxy group, and examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. And the like are particularly preferable, and a chlorine atom, a methoxy group and an ethoxy group are particularly preferably used. Note that X is a group having an effect of preventing the polysilane film from peeling off the substrate and improving the adhesion.
[0012]
m is 0.1 ≦ m ≦ 2, preferably 0.5 ≦ m ≦ 2, n is 0 ≦ n ≦ 1, preferably 0.5 ≦ n ≦ 1, and p is 0 ≦ p ≦ 0.5, preferably It is a number satisfying 0 ≦ p ≦ 0.2 and 1 ≦ m + n + p ≦ 2.5, preferably 1.5 ≦ m + n + p ≦ 2.5. q is an integer in the range of 4 ≦ q ≦ 100,000, preferably 10 ≦ q ≦ 10,000.
[0013]
On the other hand, as the CF silane, a compound represented by the following formula (2) is particularly preferably used.
[0014]
_{Y- (CH 2) n -SiR a} (OR) 3-a (2)
Wherein Y is a functional group such as a vinyl functional group, an epoxy functional group, an amino functional group, a mercapto functional group, a methacryloxy functional group, an acryloxy functional group, R is a substituted or unsubstituted monovalent hydrocarbon group, and n is 0. And an integer a to 3 and a is 0 or 1.)
Here, R can be the same monovalent hydrocarbon group as R ¹ and R ² described above, and is particularly preferably an alkyl group having 1 to 5 carbon atoms. Incidentally, as the vinyl functional group, CH ₂ ＣＨCH— and the like can be mentioned, as the epoxy functional group, a γ-glycidoxy group, a 3,4-epoxycyclohexyl group, and the like can be mentioned. As the amino functional group, NH ₂ —, NH _{2 2} CH ₂ CH ₂ NH— and the like. Examples of the mercapto functional group include a mercapto group and a methacryloxy functional group, and examples of the acryloxy functional group include a methacryloxy group and an acryloxy group.
[0015]
More specifically, vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, N-β- (aminoethyl) γ -Aminopropylmethyldimethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like. Amino group-containing alkoxysilanes are preferred.
[0016]
The addition amount can be 0.01 to 200 parts by weight based on 100 parts by weight of the polysilane. If the amount is too small, the adhesiveness is insufficient. If the amount is too large, the film formability is deteriorated, and conversely, the adhesiveness may be reduced. More preferably, 0.1 to 10 parts by weight is used.
[0017]
The addition of CF silane improves the strength of the film, and also very easily captures the palladium salt in contact with the film, thereby improving the adhesion between the metal such as copper formed by electroless plating and the substrate. Improved film formation is possible.
[0018]
The above polysilane and CF silane are usually dissolved in an appropriate organic solvent. Examples of the solvent include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; ether solvents such as tetrahydrofuran and dibutyl ether; alcohol solvents such as methanol and ethanol; and alkoxy solvents such as ethyl cellsolve and methylcellsolve. Ethanol solvents, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, butyl acetate, methyl lactate and ethyl lactate, and ether ester solvents such as PGMEA are preferably used. The addition amount can be 10 to 10,000 parts by weight based on 100 parts by weight of the silicon component (the sum of polysilane and CF silane).
[0019]
In addition, an inorganic powder such as fumed silica, an alkoxysilane such as tetraethoxysilane, or the like can be added to the composition of the present invention as needed.
[0020]
The method for forming a metal pattern of the present invention is performed by the following steps using the above-mentioned polysilane composition.
Step (1): a step of forming a polysilane pattern on the substrate surface by a stamping method, an ink jet method, or a flat plate printing method.
Step (2): a step of immersing the substrate in a solution of a catalytic metal salt such as a palladium salt and then immersing the substrate in an electroless plating solution to deposit a metal.
[0021]
Further, if necessary, the substrate in step (1) and / or step (2) is irradiated with ultraviolet light or heated to further improve the adhesion between the metal and the substrate, thereby forming a metal pattern having excellent adhesion. The formed substrate can be manufactured.
[0022]
As the substrate, an insulator such as glass, ceramic, or plastic, a semiconductor such as silicon, or a conductor such as copper can be used. In particular, resins and plastics such as phenol resins, polyester resins, epoxy resins, polyimide resins, and bismaleimide triazine resins are preferably used.
[0023]
The stamping method, the ink-jet method, and the flat-plate printing method are conventionally called printing methods, and are steps of forming a polysilane pattern film on a substrate surface, and have the following features.
[0024]
The stamping method is a method in which a rubber plate having an uneven pattern is immersed in a polysilane composition, and this rubber plate is pressed onto a substrate to transfer silicon components (polysilane and CF silane) on the projection to the substrate. is there. Although it is inferior in terms of the number of prints, it is an excellent method for forming a metal pattern on a curved surface.
[0025]
The ink jet method discharges a polysilane composition droplet in the order of picoliters corresponding to a recording signal from a liquid discharge hole toward a substrate to form a pattern, and is an excellent method for forming a fine pattern.
[0026]
The lithographic printing method is a printing plate in which an image portion and a non-image portion are formed on a plane on a support. When the polysilane composition is applied to the printing plate surface, the silicon component (polysilane and CF silane) adheres only to the lipophilic image area. This method is excellent in terms of workability, economy, and number of copies.
[0027]
After the pattern of the silicon component (polysilane and CF silane) is formed by such a method, it is effective to leave it for a while in a dry atmosphere or leave it at a temperature of about 40 to 150 ° C. under reduced pressure for drying. It is. The concentration of the solution is preferably 0.1 to 50% by weight, whereby a pattern of a silicon component (polysilane and CF silane) having a thickness in the range of 0.01 to 100 μm can be formed.
[0028]
Next, a step of immersing the substrate in a solution of a catalytic metal salt such as a palladium salt or a silver salt and then immersing the substrate in an electroless plating solution is performed.
[0029]
The palladium salt contains Pd ^{2+ and} can usually be represented in the form of Pd-Z ₂ . As Z, halogen such as CI, Br, I, acetate, trifluoroacetate, acetylacetonate, carbonate, perchlorate, nitrate, sulfate, oxide and the like are used. PdCl ₂ , PdBr ₂ , PdI ₂ , Pd (OCOCH ₃ ) ₂ , Pd (OCOCH ₃ ) ₂ , PdSO ₄ , Pd (NO ₃ ) ₂ , PdO, etc. are preferably used as examples of the palladium salt. Further, a halide such as hydrochloric acid or sodium chloride may be added to increase the stability as a solution.
[0030]
For such a solution, a solvent that dissolves the palladium salt well and does not dissolve or destroy the pattern of the silicon component is used. Such substances include water or acetone, ketones such as methyl ethyl ketone, esters such as ethyl acetate, alcohols such as methanol and ethanol, dimethylformamide, dimethyl sulfoxide, and hexamethylphosphoric triamide. Examples include aprotic polar solvents, nitromethane, and acetonitrile. In particular, water can be suitably used.
[0031]
The substrate in which the palladium salt is reduced to palladium particles on the surface of the polysilane pattern can be obtained by immersing the substrate in such a solution for about 1 second to 10 minutes, washing with water, and drying. Further, if necessary, a heat treatment at a temperature of 40 to 200 ° C. promotes reduction of palladium on the polysilane surface. The drying temperature is usually 10 to 200 ° C. and normal pressure or reduced pressure.
[0032]
Next, the substrate is immersed in an electroless plating solution to form a metal film using palladium as a catalyst.
[0033]
As the electroless plating solution, a solution containing metal ions such as copper, nickel, palladium, gold, platinum, and rhodium is preferably used. This electroless plating solution is usually prepared by adding a reducing agent such as sodium hypophosphite, hydrazine, sodium borohydride and dimethylamine borane to a water-soluble metal salt, and a complexing agent such as sodium acetate, phenylenediamine and sodium potassium tartrate. It is prepared by blending. Electroless plating solutions are commercially available and can be obtained at low cost.
[0034]
The contact condition with the electroless plating solution is preferably 15 to 120 ° C., particularly 25 to 85 ° C., for 1 minute to 16 hours, particularly 10 to 60 minutes. It is practical to form a plating film having a thickness of 0.01 to 100 μm, particularly 0.1 to 20 μm.
[0035]
After the electroless plating, if necessary, the adhesiveness between the metal and the substrate can be improved by heating. For example, the treatment is preferably performed at 60 to 300 ° C. in an inert atmosphere such as argon or in a vacuum system, and the treatment time is 1 minute to 24 hours. Thereby, the metal formed by the electroless plating has higher conductivity and hardness, and has good adhesion to the substrate.
[0036]
According to the above-described method for forming a metal pattern, a metal pattern having excellent adhesion between a metal and a substrate can be formed by an inexpensive and simple process, regardless of the type of substrate. As a result, useful metal patterns applicable to various printed circuit boards, flexible switches, battery electrodes, solar cells, sensors, antistatic protective films, electromagnetic shielding housings, integrated circuits, motor housings, flat display panels, etc. Can be widely used in the electric, electronic, and communication fields.
[0037]
【Example】
Hereinafter, the present invention will be described specifically with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.
[0038]
[Synthesis Example] Polysilane production method The following method was used for phenyl hydrogen polysilane.
[0039]
Bis (cyclopentadienyl) dichlorozirconocene was added to a diethyl ether solution of methyllithium in a flask purged with argon to prepare bis (cyclopentadienyl) dimethylzirconocene as a catalyst in the system. To this, phenylsilane was added at 50 times the molar amount of the catalyst, and the mixture was heated and stirred at 100 ° C. for 24 hours. Thereafter, molecular sieves were added and the mixture was filtered to remove the catalyst. As a result, a phenylhydrogenpolysilane solid having a weight average molecular weight of 2,600 was obtained almost quantitatively.
[0040]
[Examples and Comparative Examples]
0.8 g of polysilane (phenylhydrogenpolysilane produced in the synthesis example, hereinafter abbreviated as PPHS), 8 mg of N-β- (aminoethyl) γ-aminopropyltrimethoxysilane as CF silane (1 part by weight per 100 parts by weight of polysilane) ) Was dissolved in 9.2 g of toluene. This polysilane composition was applied on a glass fiber-containing epoxy resin plate by a stamping method, an ink jet method or a flat plate printing method to form a silane component pattern, and dried at 2 mmHg / 50 ° C. (Step 1).
[0041]
Next, a 3% aqueous solution of palladium chloride was prepared, the substrate was immersed for 1 minute, and washed with water. Next, this was immersed in an electroless plating solution (nickel sulfate 20 g, sodium hypophosphite 10 g, sodium acetate 30 g, water 1000 g) at 80 ° C. for 10 minutes to form a nickel metal pattern. After washing with pure water, drying was performed at 60 ° C. for 5 minutes, and finally, high-temperature treatment was performed at 150 ° C. for 0.5 hour in nitrogen to obtain a glass fiber-containing epoxy resin substrate on which a pattern of nickel was formed (Step 2). ).
[0042]
The conductivity of the nickel portion of this substrate is 1 × 10 ⁴ S / cm, the conductivity of the substrate portion is 1 × 10 ⁻⁹ S / cm, and the fineness of the pattern is 100 μm by the stamping method and 10 μm by the inkjet method. And 20 μm in the lithographic printing method. When the adhesion between the substrate and nickel was measured using a peeling tape, no peeling was observed.
[0043]
On the other hand, as a comparative example, the same operation was performed without adding CF silane. Partial peeling was observed due to the adhesion between the substrate and the nickel by the peeling tape test. Further, when the same operation was performed without adding polysilane, deposition of nickel was hardly observed on the substrate.
[0044]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, a metal pattern can be formed with good adhesion by the inexpensive and simple process which does not require the exposure and development processes, such as a stamping method, an inkjet method, and a lithographic printing method.

Claims (3)

A pattern film of the polysilane composition on the substrate is formed by a stamping method, an ink jet method or a flat plate printing method, a catalytic metal nucleus of electroless plating is attached on the pattern film, and then dipped in an electroless plating solution, The polysilane composition for use in a method for forming a metal pattern for depositing an electroless plating film on a pattern film, wherein the polysilane and the following formula (2)
_{Y- (CH 2) n -SiR a} (OR) 3-a (2)
(In the formula, Y is an amino functional group, R is a substituted or unsubstituted monovalent hydrocarbon group, n is an integer of 0 to 3, and a is 0 or 1.)
A polysilane composition for forming a coating for a metal pattern, comprising: a carbon functional silane represented by the formula: and a solvent dissolving the same. Polysilane has the following formula (1)
(R ¹ _m R ² _n X _p Si) _q (1)
(Wherein, R ¹ and R ² are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, X is R ¹ or an alkoxy group or a halogen atom, m is 0.1 ≦ m ≦ 2, and n is 0 ≦ n ≦ 1, p is 0 ≦ p ≦ 0.5, and a number satisfying 1 ≦ m + n + p ≦ 2.5, and q is an integer of 4 ≦ q ≦ 100,000.)
The polysilane composition according to claim 1, which is represented by: A pattern metal film of the polysilane composition is formed on a substrate by a stamping method, an ink-jet method or a lithographic printing method using the polysilane composition according to claim 1, and then a catalytic metal nucleus of electroless plating is performed on the pattern film. And then immersing it in an electroless plating solution to deposit an electroless plating film on the pattern coating.