JP2002020510A - High relative dielectric constant prepreg having excellent strength and printed circuit board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prepreg having a high relative dielectric constant, and to obtain a printed circuit board in which the prepreg has been used and which has a good strength and a high density. SOLUTION: This high relative dielectric constant prepreg characterized by nipping an organic fiber fabric as a substrate with a thermosetting resin composition containing 80 to 99 wt.% of an insulating powdery inorganic filler having a relative dielectric constant of >=500 at room temperature to adhere the resin composition to the substrate. The thermosetting resin composition preferably is a resin composition obtained by compounding an insulating inorganic filler having a relative dielectric constant of >=500 at room temperature and a specific surface area of 0.30 to 1.00 m2/g with a resin composition comprising (a) a polyfunctional cyanate compound, (b) an epoxy resin liquid at room temperature, and a thermal curing catalyst. The high relative dielectric constant prepreg is used to produce the high density printed circuit board. Thereby, the prepreg having the high relative dielectric constant can be produced, and the printed circuit board in which the prepreg has been used and which has excellent heat resistance, electric characteristics after the absorption of moisture, excellent adhesivity to copper foils, excellent strength, and so on can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a prepreg for a stage and a printed wiring board mainly using the copper-clad board as a capacitor. In particular, printed wiring boards obtained by drilling with a carbon dioxide laser are mounted on a semiconductor chip as a high-density small printed wiring board, and are used for new compact and lightweight semiconductor plastic packages and amplifiers. Are suitable.

[0002]

2. Description of the Related Art In recent years, high-density multilayer printed wiring boards have been used in electronic devices that are becoming smaller, thinner and lighter. A layer having a high relative dielectric constant is provided in the inner and outer layers of the printed wiring board, and this layer can be used as a capacitor to improve the mounting density. To provide a high dielectric constant layer on the inner layer, outer layer or substrate of a multilayer board, epoxy resin, modified polyphenylene oxide resin, etc.
For example, blending a high dielectric constant inorganic powder such as barium titanate, impregnating it with a fiber base material such as a glass cloth, drying and drying a plurality of prepregs, and disposing a copper foil on the outermost layer. It has been proposed to form a high relative dielectric constant copper-clad laminate by lamination molding. Such an epoxy resin, a high dielectric constant copper-clad laminate using a modified polyphenylene oxide resin and the like are disclosed in JP-A-55-57212, JP-A-61-136281, and JP-A-6-136281.
1-167547, JP-A-62-19451 and JP-B-5-415. When a prepreg is prepared using a glass cloth base material, if the amount of the inorganic filler in the resin composition is too large as 80% by weight, impregnation and drying will result in the adhesion of the resin composition to the surface layer of the glass cloth base material. It is difficult and non-uniform, so that prepreg cannot be prepared. In addition, there is no case in which an inorganic filler is added in a large amount because it has a large specific gravity and precipitates when dispersed in a varnish. For this reason, in each proposal, only those having a relative dielectric constant of about 10 to 20 in the examples were obtained. Therefore, a capacitor having a large capacitance could not be formed, and it could not be used as a laminate having a capacitor function.

On the other hand, when a resin composition comprising a general thermosetting resin and an inorganic powder having a high relative dielectric constant is used, when a large amount of an inorganic filler is used in an amount of 80% by weight or more, the obtained copper The laminated laminate was brittle, and when copper foil was adhered, the adhesive strength was extremely low and it was difficult to use a printed wiring board. Furthermore, as shown in JP-A-9-12742, without using a glass cloth substrate, a high dielectric constant film obtained by mixing a thermosetting resin and an inorganic powder having a relative dielectric constant of 50 or more. In this case, in order to form a film, the viscosity of the resin is high, and the upper limit of the addition amount of the inorganic filler is about 60% by weight. Further, the relative permittivity of the obtained copper-clad laminate was as low as about 10, and a relative permittivity of 20 or more was not obtained.

[0004]

DISCLOSURE OF THE INVENTION The present invention has solved the above-mentioned problems. The copper foil has a high adhesive strength, a high strength, and a relative dielectric constant of 10 or more, preferably 20 or more. It is an object of the present invention to provide a prepreg having a high relative dielectric constant, which can be processed in the same manner as the glass cloth base thermosetting resin prepreg, and a printed wiring board using the copper-clad laminate. Another object of the present invention is to provide a high-density printed wiring board in which small-diameter holes are formed by a carbon dioxide laser.

[0005]

According to the present invention, an organic fiber cloth is used as a base material, and an insulating inorganic filler having a relative dielectric constant of 500 or more at room temperature on one surface of a thermoplastic resin film is 80 to 99% by weight. The thermosetting resin composition layer formed in the thermosetting resin is formed and placed on both sides so that the resin side faces the organic fiber cloth side. A prepreg attached to a fiber cloth is provided. Furthermore, the present invention
A printed wiring board using a copper-clad board obtained from the prepreg is provided. Further, as a thermosetting resin, (a) a polyfunctional cyanate compound, 100 parts by weight of the cyanate ester prepolymer, (b) epoxy resin liquid at room temperature
50 to 10,000 parts by weight, and 0.005 to 10 parts by weight of a thermosetting catalyst with respect to 100 parts by weight of (a + b), and an insulating inorganic filler having a relative dielectric constant of 500 or more at room temperature. 80-9 powder
The present invention provides a high relative dielectric constant prepreg having a relative dielectric constant of preferably 20 or more, which is prepared by mixing uniformly to 9% by weight. The printed wiring board of the present invention has excellent copper foil adhesive strength, strong mechanical strength, high heat resistance, high relative dielectric constant, excellent small-diameter drilling ability with a carbon dioxide laser, and excellent connection reliability. ing.

The copper clad laminate obtained using the prepreg of the present invention can be drilled with a mechanical drill.
Drilling with a laser is suitable because of a large amount of inorganic filler and a large amount of drill wear. From the viewpoint of processing speed and the like, a carbon dioxide laser is preferred. According to the present invention, a hole assisting layer for a carbon dioxide gas laser is formed on the surface of a copper-clad board using the high relative dielectric constant prepreg of the present invention, and a carbon dioxide laser is directly irradiated from above to form a through hole and / or a blind. Provided is a printed wiring board formed by forming a via hole.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention uses an organic fiber base material,
An insulating inorganic filler with a relative dielectric constant of 500 or more
9% by weight of the thermosetting resin composition layer is arranged, heated,
Attached to the central organic substrate under pressure to make a prepreg,
Using this, a copper clad board or a multilayer board is formed, and a hole is formed and a circuit is formed to form a printed wiring board. Addition of a large amount of an inorganic filler, particularly 80% by weight or more, causes disadvantages such as a decrease in copper foil adhesion. Therefore, a copper-clad laminate having a large amount of an inorganic filler added has not been developed in the conventional proposals. In the present invention, in particular, in order to produce a copper-clad laminate having a relative dielectric constant of 20 or more and a copper foil adhesive force and a printed wiring board using the same, the average particle diameter of the inorganic filler is preferably 4-30μ
m, specific surface area of 0.30 to 1.00 m ² / g, barium titanate ceramic, lead titanate ceramic, calcium titanate ceramic, strontium titanate ceramic, magnesium titanate ceramic, bismuth titanate ceramic, A powder which contains at least one or more of lead zirconate-based ceramics and / or is sintered and then pulverized is blended.

[0008] The resin is not particularly limited. For example,
A generally known thermosetting resin such as a polyfunctional cyanate resin, a polyfunctional maleimide resin, a polyimide resin, an epoxy resin, and a double-bonded polyphenylene oxide resin is used. These are used alone or in combination of two or more. Among them, migration resistance,
From the viewpoints of heat resistance, electrical insulation after moisture absorption, and the like, a polyfunctional cyanate ester resin is preferably used. The amount used is preferably (a) a polyfunctional cyanate ester compound, based on 100 parts by weight of the cyanate ester prepolymer, (b)
Mix 50 to 10,000 parts by weight of epoxy resin that is liquid at room temperature,
0.005 to 10 parts of the thermosetting catalyst with respect to 100 parts by weight of the component (a + b).
Use is made of a thermosetting resin composition containing a resin composition blended in parts by weight as an essential component.

The polyfunctional cyanate compound used in the present invention is a compound having two or more cyanato groups in a molecule. Specific examples include 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3
-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4-dicyanatobiphenyl, bis ( 4-dicyanatophenyl) methane, 2,2-
Bis (4-cyanatophenyl) propane, 2,2-bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-Cyanatophenyl) sulfone, tris
(4-cyanatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide.

In addition to these, Japanese Patent Publication Nos. 41-1928 and 43-1846
8, polyfunctional cyanate compounds described in JP-A-44-4791, JP-A-45-11712, JP-A-46-41112, JP-A-47-26853 and JP-A-51-63149 can also be used. Further, a prepolymer having a molecular weight of 400 to 6,000 and having a triazine ring formed by trimerization of a cyanato group of these polyfunctional cyanate compounds is used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer with a catalyst such as an acid such as a mineral acid or a Lewis acid; a base such as a tertiary amine such as sodium alcoholate; or a salt such as sodium carbonate. It can be obtained by: The prepolymer also contains some unreacted monomers and is in the form of a mixture of the monomer and the prepolymer, and such a raw material is suitably used for the purpose of the present invention. Although it is possible to use it without a solvent by making it compatible with a liquid epoxy resin, it is generally used by dissolving it in a soluble organic solvent.

As the epoxy resin which is liquid at room temperature, a generally known epoxy resin can be used. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, diglycidylated polyether polyol, epoxidized acid anhydride, alicyclic epoxy resin, etc. alone or in combination of two or more Used. The amount used is 50 to 10,000 parts by weight, preferably 100 to 5,000 parts by weight, based on 100 parts by weight of the polyfunctional cyanate ester compound and the cyanate ester prepolymer.

Various additives can be added to the thermosetting resin composition of the present invention, if desired, as long as the inherent properties of the composition are not impaired. These additives include polymerizable double bond-containing monomers such as unsaturated polyesters and prepolymers thereof; polybutadiene, epoxidized butadiene, maleated butadiene, butadiene-
Low molecular weight liquid to high molecular weight elastic rubbers such as acrylonitrile copolymer, polychloroprene, butadiene-styrene copolymer, polyisoprene, butyl rubber, fluororubber, natural rubber; polyethylene, polypropylene, polybutene, poly-4-methyl Penten, polystyrene, AS
Resin, ABS resin, MBS resin, styrene-isoprene rubber,
Polyethylene-propylene copolymer, 4-fluoroethylene-
6-fluorinated ethylene copolymers; high molecular weight prepolymers or oligomers such as polycarbonate, polyphenylene ether, polysulfone, polyester, and polyphenylene sulfide; and polyurethane are exemplified and used as appropriate. In addition, other known inorganic and organic fillers,
Various additives such as dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, and thixotropic agents may be used as desired. They are used in an appropriate combination. If necessary, the compound having a reactive group is appropriately blended with a curing agent and a catalyst.

The thermosetting resin composition itself is cured by heating, but when the curing speed is slow and the workability and economic efficiency are poor, a known thermosetting catalyst for the thermosetting resin used is used. Can be used. The amount used is 0.005 to 10 parts by weight, preferably 0.01 to 5% by weight, based on 100 parts by weight of the thermosetting resin.

The insulating inorganic filler used in the present invention is not particularly limited as long as its relative dielectric constant is 500 or more at room temperature. Particularly, a titanate compound ceramic is preferable. In particular,
One or more of barium titanate-based ceramic, strontium titanate-based ceramic, lead titanate-based ceramic, magnesium titanate-based ceramic, bismuth titanate-based ceramic, calcium titanate-based ceramic, and lead zirconate-based ceramic are exemplified. In terms of composition, these are components alone or systems containing other small amounts of additives, and the crystal structure of the main component is maintained.
These may be used alone or in combination of two or more.
In addition, a powder obtained by sintering one or more of these inorganic powders and / or one or more of them is used. Further, the needle-like whiskers may be used alone or partially added.

The method for uniformly kneading the components of the present invention is as follows:
Generally known methods can be used. For example, after the respective components are blended, they are kneaded with a three-roll mill at room temperature or under heating, or generally known materials such as a ball mill and a raikai machine are used. In addition, a solvent is added so that the viscosity is suitable for the processing method.

As the substrate, an organic fiber substrate is used.
Although there is no particular limitation on the type, nonwoven fabrics and woven fabrics such as liquid crystal polyester fibers, polybenzazole fibers, and wholly aromatic polyamide fibers are preferably used. In particular, from the point of drilling holes such as mechanical drills and carbon dioxide lasers,
A liquid crystal polyester nonwoven fabric is preferably used. Patent 1 uses a binder instead of a binder by attaching a binder to connect the fibers or mixing the pulp and the fibers and heating and melting the pulp at a temperature of about 300 ° C.
For example, the nonwoven fabric disclosed in 1-255908 can be used. When using a binder, the amount is not particularly limited, but in order to maintain the strength of the nonwoven fabric, preferably 3 to 8% by weight
Attach.

The method for forming a prepreg by forming a resin layer on the surface of an organic substrate is not particularly limited, but preferably, an insulating inorganic filler is added to the resin composition, and if necessary, a solvent is added. After applying the varnish to one side of the release film and drying to form a B stage, place the resin on both sides of the organic substrate so that the resin faces the substrate side, and then apply heat and pressure. A method of forming an integrated B-stage prepreg by pressing with a roll or the like, a method of adding an inorganic filler to a solventless resin composition, kneading with a raikai machine or the like, and adhering the mixture to both sides of an organic fiber cloth while extruding the same. For example, a generally known method can be used.

A copper foil, preferably an electrolytic copper foil, is placed on at least one side of the obtained prepreg, and is laminated under heat and pressure to form a copper-clad laminate. Although this copper foil is not particularly limited, an electrolytic copper foil having a thickness of 3 to 12 μm for a double-sided copper clad board and a thickness of 9 to 35 μm for use as an inner layer board is preferably used.

The lamination molding conditions for the copper clad board used in the present invention are generally a temperature of 150 to 250 ° C., a pressure of 5 to 50 kgf / cm ² and a time of 1 to 5 hours. Further, it is preferable to carry out lamination molding under vacuum. Of course, a laminate can be formed by laminating and molding without using a copper foil, and copper can be adhered by a generally known method such as sputtering. However, from the viewpoint of workability and adhesion,
Direct lamination molding is preferred.

When a through hole and / or a blind via hole is made in the copper clad board obtained in the present invention, it is preferable that a hole having a diameter of more than 180 μm is formed by a mechanical drill.
The through holes and / or blind via holes having a size of 20 μm or more and 180 μm or less are preferably formed with a laser. 20μm
The through holes and / or blind via holes having a diameter of less than 80 μm are preferably formed by an excimer laser or a YAG laser. Further, the through-holes and / or blind via holes having a diameter of 80 μm or more and 180 mμ or less may be provided by subjecting the copper foil surface to metal oxide treatment or chemical treatment (eg, CZ treatment, Mec Co., Ltd.)
A sheet-like or paint-like auxiliary material composed of a resin composition containing one or more of metal compound powder, carbon powder, or metal powder having a binding energy of 300 kJ / mol or more at 900 ° C. or more is preferably used. It is arranged on the copper foil surface with a thickness of ２００200 μm. CO2 laser power, preferably 20
Drilling is performed by directly irradiating the copper foil surface at で 60 mJ.

Alternatively, a nickel metal layer or a nickel alloy layer is formed on the shiny surface of the copper foil as an auxiliary drilling layer. Drilling is performed by directly irradiating a carbon dioxide laser directly from above. In this case, the output of the carbon dioxide gas laser is preferably applied directly to the surface of the copper foil at preferably 5 to 60 mJ. Of course, other generally known drilling methods can be used.

The auxiliary material used in the present invention has a melting point of 90.
As the metal compound having a binding energy of 300 kJ / mol or more at 0 ° C. or more, generally known metal compounds can be used. Specifically, as the oxide, titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, manganese dioxide, zinc oxide such as zinc oxide , Silicon oxide, aluminum oxide, rare earth oxides, cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, and tungsten oxides such as tungsten oxide. Examples of the non-oxide include generally known ones such as silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, and rare earth oxysulfide. In addition, carbon can also be used. Further, various glasses which are a mixture of the metal oxide powders may be mentioned. In addition, carbon powders may be mentioned, and further, simple substances such as silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc and the like. An alloy metal powder is used. These may be used alone or in combination of two or more. The average particle size is
Although not particularly limited, 1 μm or less is preferable.

Since the molecules are dissociated or melted and scattered by the irradiation of the carbon dioxide laser, the metal does not adhere to the hole walls and the like, and does not adversely affect the semiconductor chip and the adhesion to the hole walls. preferable. Since Na, K, Cl ions and the like particularly adversely affect the reliability of the semiconductor, those containing these components are not suitable. The compounding amount is 3 to 97 vol%, preferably 5 to 95 vol%, and is preferably mixed with the water-soluble resin and uniformly dispersed.

The water-soluble resin for using the metal compound or the like as a coating film or sheet-like auxiliary material is not particularly limited, but may be kneaded and applied to the surface of a copper foil and dried, or formed into a sheet. In this case, a material that does not cause peeling and missing is selected. For example, generally known materials such as polyvinyl alcohol, polyester, polyether and starch are used.

The method for preparing the metal compound powder, carbon powder, or the composition comprising the metal powder and the resin is not particularly limited, but is kneaded at a high temperature without a solvent in a kneader or the like, and extruded into a sheet on a thermoplastic film. A method of dissolving a water-soluble resin in water, adding the powder to the mixture, stirring and mixing the mixture uniformly, and applying the mixture to a thermoplastic film as a paint, followed by drying to form a film. And other generally known methods. The thickness is not particularly limited, but is generally used in a total thickness of 30 to 200 μm. In addition, it is also possible to perform a chemical solution treatment on the surface of the copper foil and then similarly drill holes. Although this processing is not particularly limited, for example, CZ
Processing (MEC Corporation) can be suitably used.

On the back side, it is preferable to use a backup sheet in which a water-soluble resin is adhered on a metal plate on the back side in order to avoid damage to the table of the carbon dioxide laser when forming the through holes. The auxiliary material is applied as a coating film on the copper foil surface or is applied on a thermoplastic film to form a sheet. When the sheet is laminated on the copper foil surface under heating and pressurization, the auxiliary resin and the backup sheet are coated with the resin layer facing the copper foil surface, and the temperature is generally 40 to 150 rolls.
° C, preferably 60-120 ° C, and the linear pressure is generally 0.5-20 kgf /
Lamination is performed at a pressure of 1 cm to 10 kgf / cm, and the resin layer is melted and brought into close contact with the copper foil surface. The selection of the temperature depends on the melting point of the water-soluble resin used, and also depends on the linear pressure and the laminating speed. In general, lamination is performed at a temperature higher by 5 to 20 ° C. than the melting point of the water-soluble resin. In the case of close contact at room temperature, the surface of the coating resin layer of 3 μm or less is moistened with water before lamination to dissolve a small amount of the water-soluble resin, and is laminated under the same pressure. The method of moistening with water is not particularly limited, but, for example, a method in which water is continuously applied to the coating resin surface by a roll, and thereafter, a method of continuously laminating the surface of the copper-clad laminate, the water is sprayed. A method of continuously spraying the coating film surface and then continuously laminating the surface of the copper-clad laminate may be used.

A carbon dioxide laser, preferably with an output of 5-60
When holes are formed by mJ irradiation, burrs occur around the holes. This is a double-sided copper-clad laminate with thin copper foil,
There is no particular problem, the resin remaining on the copper foil surface is removed by gas phase or liquid phase treatment, copper plating is performed on the inside of the hole as it is, 50% by volume or more of the hole inside is copper plated, and the surface layer is also plated at the same time Thus, the thickness of the copper foil can be reduced to 18 μm or less. However, preferably, the etching solution is sprayed or sucked through the hole, and the overhanging copper foil burr is dissolved and removed at the same time, and the remaining thickness of the surface copper foil is 2 to 7 μm, preferably 3 to 5 μm. And copper plating. In this case, etching with a chemical solution is more preferable than mechanical polishing in terms of removing burrs from holes, dimensional change due to polishing, and the like. Creates high-density printed wiring boards with no defects such as short-circuits or pattern breaks in the formation of fine wire circuits on the front and back copper foils obtained by plating up with subsequent metal plating because the copper foils become thinner can do. When thinning the front and back copper foils by etching, the resin layer adhering to the surface of the inner copper foil exposed inside the holes is preferably removed by etching after at least gas phase treatment. The inside of the hole can be filled with copper plating by 50% or more. In addition, in the case of the last through-hole, by connecting the copper foil in the surface layer and the copper foil inside the hole, a hole with extremely excellent connection can be obtained. In addition, the processing speed was remarkably faster as compared with the case of drilling, and the productivity was good and the economical efficiency was excellent. The method for etching and removing copper burrs generated in the holes of the present invention is not particularly limited. For example, JP-A-02-22887, JP-A-02-22896,
02-25089, 02-25090, 02-59337, 02-60189, same
02-166789, 03-25995, 03-60183, 03-94491, 0
According to a method of dissolving and removing a metal surface with a chemical (referred to as a SUEP method) disclosed in JP-A-4-199592 and JP-A-04-263488. The etching rate is generally 0.02 to 1.0 μm / sec.

The carbon dioxide laser is in the infrared wavelength range.
Wavelengths of 9.3 to 10.6 μm are commonly used. Preferably, the copper foil is processed at a power of 5 to 60 mJ / pulse to make a hole. Excimer lasers generally have wavelengths of 248 to 308 nm, and YAG lasers have wavelengths of 351 to 355 nm, but are not limited thereto. The processing speed of the carbon dioxide laser is remarkably fast and economical.

When drilling through holes and / or blind via holes, a method of irradiating energy selected from 5 to 60 mJ from the beginning to the end, a method of changing the energy in the middle, and the like can be used. When removing the surface copper foil,
By selecting a higher energy, for example, 20 to 60 mJ, the number of irradiation shots is small and the efficiency is good. When processing the intermediate resin layer, high output is not necessarily required, and it can be appropriately selected depending on the base material and the resin. For example, output 5
It is also possible to choose from ~ 35mJ. Of course, high-power processing can be performed until the end. The processing conditions can be changed with or without the inner layer copper foil inside the hole.

In most cases, a resin layer of about 1 μm remains in the inner layer copper foil inside the hole processed by the carbon dioxide laser. Further, when a hole is drilled with a mechanical drill, smear may remain. By removing this resin layer, the connection reliability between the further copper plating and the copper in the inner and outer layers is improved. In order to remove the resin layer, generally known treatments such as desmear treatment can be performed.However, when the liquid does not reach the inside of the small-diameter hole, the removal residue of the resin layer remaining on the copper foil surface of the inner layer occurs. Connection failure with copper plating may occur. Therefore, more preferably, the inside of the hole is first treated in the gas phase to completely remove the residual layer of the resin, and then the inside of the hole is wet-treated, preferably by using ultrasonic waves.

As the gas phase treatment, generally known treatments can be used, and examples thereof include a plasma treatment and a low-pressure ultraviolet treatment. As the plasma, low-temperature plasma in which molecules are partially excited by a high-frequency power source and ionized is used. For this, high-speed processing using ion bombardment and gentle processing using radical species are generally used, and reactive gases and inert gases are used as processing gases. As the reactive gas, oxygen is mainly used, and the surface is chemically treated. As the inert gas, an argon gas is mainly used. Using this argon gas or the like, physical surface treatment is performed. Physical treatment uses ion bombardment to clean the surface. The low ultraviolet ray is an ultraviolet ray having a short wavelength region, and irradiates a short wavelength region having a peak at 184.9 nm and 253.7 nm, and decomposes and removes the resin layer. Then, since the resin surface is often hydrophobized, especially in the case of a small-diameter hole, it is preferable to perform a wet treatment using ultrasonic waves and then perform a copper plating. The wetting treatment is not particularly limited, but includes, for example, an aqueous solution of potassium permanganate, an aqueous solution for soft etching, and the like.

Although the inside of the hole can be electrically connected without being filled with copper plating, it is preferably filled with 50% by volume or more, more preferably 90% by volume or more. However, if the plating time is lengthened and the inside of the hole is filled, workability is poor,
A method using an additive for pulse plating (manufactured by Nippon Rironal Co., Ltd.) suitable for filling holes is preferably used.

[0033]

The present invention will be specifically described below with reference to examples and comparative examples. Unless otherwise specified, “parts” indicates parts by weight.

Examples 1 to 5 2,2-bis (4-cyanatophenyl) propane monomer (component
1,000 parts of A-1) were melted at 150 ° C., and reacted with stirring for 4 hours to obtain a prepolymer having an average molecular weight of 1,900 (component A-2). As a liquid epoxy resin at room temperature, bisphenol A type epoxy resin (trade name: Epicoat 828,
Yuka Shell Epoxy Co., Ltd., component B-1), bisphenol F type epoxy resin (trade name: EXA830LVP, Dainippon Ink & Chemicals, Inc., component B-2), novolak type epoxy resin (trade name: DEN431, manufactured by Dow Chemical Co., Ltd., ingredient B
-3), Cresol novolak type epoxy resin (Product name: ES
CN220F, manufactured by Sumitomo Chemical Co., Ltd., component B-4) was blended and used as a thermosetting catalyst to give iron acetylacetone (component C-1), 2-ethyl-4-methylimidazole (component C-2), and As an additive, an epoxy silane coupling agent (trade name: A-187,
Nippon Yunika Co., Ltd., component D-1), dicyandiamide (component
E-1) to give a varnish. Barium titanate ceramics (relative dielectric constant at 1 MHz at room temperature: 2,010, specific surface area 0.41 m ² / g, component F-1), bismuth titanate ceramics (at room temperature) Relative permittivity: 733, specific surface area 0.52 m ² / g, component F-2), barium titanate-calcium stannate ceramic (relative permittivity at room temperature: 5,020, specific surface area 0.45 m ² / g, component F-3),
Using a lead titanate-based ceramic (relative dielectric constant at room temperature of 1,700, specific surface area of 0.90 m ² / g, component F-4), mix as shown in Table 1, and uniformly knead with a raikai machine for 10 minutes. A varnish having a high viscosity was used as a varnish having an appropriate viscosity for application by adding a small amount of methyl ethyl ketone. Apply this varnish to thickness 50
μm polyethylene terephthalate (PET) film on one side continuously to a thickness of 40 μm, dried, 170
A B-staged resin sheet Z was prepared such that the resin flow at 5 ° C., 20 kgf / cm ² and 5 minutes was 1 to 20 mm.

The varnish was prepared by using a fiber having a diameter of 13 μm and a length of 16 m.
m liquid crystal polyester fibers, dispersed in polyethylene oxide dispersion solution, creating an adhesive solution using a non-woven fabric epoxy resin emulsion and a silane coupling agent papermaking such basis weight is 30 g / m ^2, it 6% by weight and dried at 150 ° C.
After placing the resin sheet Z with the film facing the outside, 100 ° C, continuous lamination with a roll of 5 kgf / cm and unifying it into a B-stage prepreg Y, then 530 x 53
It was cut to 0 mm. The PET film of the B-stage prepreg was peeled off, and three sheets of the PET film were used. A 12 μm general electrolytic copper foil (JTC-LP, manufactured by Japan Energy Co., Ltd.) was placed on both sides of the PET film, and 200 ° C., 30 kgf / cm ² Under a vacuum of 30 mmHg or less for 2 hours to obtain a double-sided copper-clad laminate.

On the other hand, 800 parts of black copper oxide powder (average particle diameter: 0.8 μm) as a metal oxide powder was added to a varnish prepared by dissolving polyvinyl alcohol powder in water, and uniformly stirred and mixed.
This was applied on one side of a PET film having a thickness of 50 μm so as to have a thickness of 30 μm, and dried at 110 ° C. for 30 minutes to prepare an auxiliary material P having a metal compound powder content of 45 vol%. Also thickness 50
This varnish was applied to one side of a μm aluminum foil so as to have a thickness of 20 μm, and dried to prepare a backup sheet Q. The auxiliary material P on the upper side of the double-sided copper-clad laminate, the backup sheet Q on the lower side, disposed so that the resin surface faces the copper foil side, and laminated at 100 ° C., 5 kgf / cm, and the hole diameter is 100 μm. A total of 144 holes in a 20 mm square were directly irradiated with 4 shots at a power of 30 mJ / pulse by a CO2 laser,
A through-hole of a block (10080 holes in total) was opened, SUEP treatment was performed, the copper foil on the surface layer was etched until the thickness became 3 μm, and burrs around the hole were also dissolved and removed. Copper plating
15 μm was attached. Use the existing method for the front and back circuits (line /
(Space = 50/50 μm), lands for solder balls, etc. were formed, and at least the semiconductor chip mounting portion, pad portions, and solder ball pad portions were covered with a plating resist, and nickel and gold plating were performed to produce a printed wiring board. .
Table 2 shows the evaluation results.

Comparative Example 1 2,000 parts of an epoxy resin (trade name: Epicoat 5045, manufactured by Yuka Shell Epoxy Co., Ltd.), 70 parts of dicyandiamide, and 2 parts of 2-ethylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and stirred. The mixture was mixed and dispersed uniformly to obtain a varnish G (this solid resin component was designated as Component B-5). A bismuth titanate ceramic (particle size 0.5
-5 μm, average particle diameter 1.3 μm, specific surface area 1.29 m ² / g, relative dielectric constant 730, F-5) as shown in Table 1 and uniformly kneaded to obtain a 50 μm thick glass. The woven fabric was impregnated and dried to prepare a B-stage prepreg. in this case,
Due to the large amount of resin, unevenness and cracks occurred on the surface of the glass woven fabric. A place where coating was good was selected, and an electrolytic copper foil of 12 μm was arranged on both sides, and laminated and formed at 190 ° C., 30 kgf / cm ² , and a vacuum of 30 mmHg or less for 2 hours to prepare a double-sided copper-clad laminate. Hole diameter 200μm on this copper-clad laminate with a mechanical drill
Was formed. Without performing the SUEP treatment, normal copper plating was adhered by 15 μm. Using this, a printed wiring board was prepared. Table 2 shows the evaluation results.

Comparative Example 2 Titanium dioxide shellac powder (specific surface area: 1.26 m ² / g, relative dielectric constant: 25, component F-6) was added to varnish G of Comparative Example 1 so as to be 90% by weight. This was mixed well with a stirrer to form a varnish, impregnated into a glass woven fabric, and dried to obtain a prepreg, which also had a large amount of an inorganic filler, which caused uneven coating and cracking. A good part was selected, four of these were used, and a 12 μm electrolytic copper foil was placed on both sides thereof, and laminated and formed in the same manner as in Comparative Example 1 to obtain a copper-clad laminate. Similarly, holes were drilled with a mechanical drill to obtain a printed wiring board.
Table 2 shows the evaluation results.

Comparative Example 3 The varnish of Comparative Example 2 was continuously applied to a 12 μm electrolytic copper foil and dried to form a 60 μm thick copper foil with a B-stage resin, which was arranged so that two sheets of resin faced each other. Then 190
C., 30 kgf / cm ² , molded under vacuum of 30 mmHg or less for 2 hours to prepare a double-sided copper-clad board. A through hole having a hole diameter of 200 μm was made in this copper clad plate with a mechanical drill, and normal copper plating was applied to 15 μm without performing the SUEP treatment. Using this, a printed wiring board was prepared. Table 2 shows the evaluation results.

Table 1 Example of blending composition Comparative Example 1 2 3 4 5 1 2 3 A-1 15 20 25 A-2 13 20 20 60 B-1 5 10 B-2 22 10 15 20 10 B- 3 50 45 40 15 10 B-4 65 10 B-5 100 100 100 C-1 0.08 0.10 0.11 0.12 C-2 0.5 0.1 0.5 D-1 2 2 2 2 2 2 2 2 E-1 5 F-1 567 600 F-2 900 F-3 567 F-4 900 700 F-5 400 F-6 900 900 Inorganic filled particle size width (μm) 3-41 3-40 3-42 5-38 5-41 0.5-5 1- 5 1-5 Average particle size (μm) 10 6 12 20 12 1.3 2.1 2.1

Table 2 Item Example Comparison Example 1 2 3 4 5 1 2 3 Void after molding None None None None None Slight void None Yes Large Copper foil adhesive strength (12 μm) (kgf / cm) 0.96 0.71 1.10 0.87 0.61 0.48 ー 0.22 Solder heat resistance after PCT (121 ℃ ・ 203kP 2hrs.) Treatment (260 ℃ ・ 30sec. Immersion) Abnormal None Swelling Less swelling Large Anomaly occurrence None Pattern break and short (pieces) 0/200 0/200 0/200 0/200 0/200 64/200 60/200 58/200 Glass transition temperature (° C) 190 211 226 185 233 137 138 138 Through-hole heat cycle test (%) 150 cycles 1.9 2.1 1.8 2.7 1.6 8.8 15.1 35.9 relative permittivity (1MHz) 21 19 23 32 46 11 over 7.8 pressure cooker insulation resistance value after processing (Omega) normal state over 5x10 ¹⁴ over 5x10 ¹⁴ over 6x10 ¹⁴ over over 200hrs. 3x10 ¹⁰ 3x10 ^{10 <10 8} migration resistance (Omega) normal state over 5x10 ¹³ over 3x10 ¹³ over 6x10 ¹³ over over ^{200hrs. 6x10 11 5x10 11 3x10 9} 500hrs. 9x10 10 9x10 10 <10 8 flexural strength (kgf / cm ² ) 13 11 14 10 14 ー ー 2

<Measurement method> 1) Void after lamination molding The lamination-molded copper foil was removed by etching, and voids were visually observed. 2) Adhesive strength of copper foil Measured according to JIS C6481. 3) PCT (pressure cooker; 121 ℃ ・ 203kPa, 2hrs.)
Solder heat resistance after treatment After treatment, the specimen was immersed in solder at 260 ° C. for 30 sec. 4) Create a board without holes in the same way as in the circuit pattern break, short circuit, example, comparative example,
After a comb-shaped pattern of line / space = 50/50 μm was formed, 200 patterns after etching were visually observed with a magnifying glass, and the total of the cut and short-circuited patterns was indicated in the molecule. 5) Glass transition temperature Measured by the DMA method. 6) Through hole heat cycle test Create a land diameter of 300μm in each through hole hole, connect 900 holes alternately front and back, one cycle is 260 ° C, solder, immersion 30 seconds → room temperature, 5 minutes, up to 150 cycles The maximum value of the rate of change of the resistance value was shown. 7) Insulation resistance value after pressure cooker processing A comb-shaped pattern between terminals (line / space = 50/50 μm) was created, and the prepregs used were arranged on each of them, and the laminate was molded at 121 ° C. and 203 kPa. After processing for a predetermined time at, perform post-processing at 25 ° C and 60% RH for 2 hours, and
VDC was applied to measure the insulation resistance between the terminals. 8) Migration resistance The test piece of 6) was applied at 85 ° C. and 85% RH at 50 VDC, and the insulation resistance between the terminals was measured. 9) Dielectric constant Measured with an LCR meter and calculated by calculation.

[0043]

EFFECTS OF THE INVENTION A thermosetting resin composition comprising an organic fiber base material and a dielectric constant of 500 or more on both surfaces thereof, and preferably having a specific surface area of 0.30 to 1.00 m ² / g. In
(a) polyfunctional cyanate ester monomer, 100 parts by weight of the cyanate ester prepolymer, (b) 50 to 10,000 parts by weight of a liquid epoxy resin mixed at room temperature, 100 parts by weight of this (a + b) component Parts by weight, a high-permittivity resin composition obtained by uniformly mixing the resin component containing 0.005 to 10 parts by weight of a thermosetting catalyst to 80 to 99% by weight, preferably 85 to 95% by weight. Using a prepreg made by attaching it to a copper-clad laminate and using it as a printed wiring board, it has excellent adhesion and strength to copper foil, excellent heat resistance, excellent electrical insulation after moisture absorption, etc. A dielectric constant of 20 or more was obtained, and a useful one as a capacitor or the like was produced. Also, by using the auxiliary layer on the copper-clad laminate, it is possible to directly pierce a small-diameter hole by irradiating a high-energy carbon dioxide laser, and obtain a high-density printed wiring board. Was.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 1/03 610 H05K 1/03 610T 610R 3/00 3/00 N 3/26 3/26 F F term (Ref.) AA02 AA07 AA13 AA16 BB16 BB24 BB67 DD80 EE12 EE43 EE52 GG11

Claims (8)

[Claims] An organic fiber cloth as a substrate is sandwiched between a thermosetting resin composition containing 80 to 99% by weight of an insulating inorganic filler powder having a relative dielectric constant of 500 or more at room temperature. A high-permittivity prepreg characterized by being attached. 2. An epoxy resin which is liquid at room temperature with respect to (a) a polyfunctional cyanate ester monomer and 100 parts by weight of the cyanate ester prepolymer.
2. The resin composition according to claim 1, wherein 50 to 10,000 parts by weight is blended, and a resin composition in which 0.005 to 10 parts by weight of a thermosetting catalyst is blended with respect to 100 parts by weight of (a + b) is used. High dielectric constant prepreg. 3. The insulating inorganic filler powder comprises a barium titanate-based ceramic, a strontium titanate-based ceramic, a lead titanate-based ceramic, a calcium titanate-based ceramic, a bismuth titanate-based ceramic, or a lead zirconate-based ceramic. The high relative dielectric constant prepreg according to claim 1 or 2, which is an inorganic powder containing at least one or more kinds thereof and / or a powder obtained by sintering and pulverizing at least one kind of these. 4. An insulating inorganic filler having an average particle size of 4 to 3
4. The high relative dielectric constant prepreg according to claim 1, wherein the prepreg has a specific surface area of 0.3 to 1.00 m ² / g. . 5. The high relative dielectric constant prepreg according to claim 1, wherein said organic fiber cloth is an aromatic polyester fiber nonwoven fabric. 6. A printed wiring formed by forming a through-hole and / or a blind via hole in a copper-clad board using the high-permittivity prepreg according to any one of claims 1 to 5. Board. 7. A carbon dioxide gas laser drilling auxiliary layer is formed on the surface of a copper-clad board using the high relative dielectric constant prepreg according to any one of claims 1 to 5, and a carbon dioxide laser is directly applied from above. The printed wiring board according to claim 6, wherein the printed wiring board is formed by irradiating to form a through hole and / or a blind via hole. 8. After piercing with a carbon dioxide gas laser, a chemical solution is used to dissolve and remove the copper foil burrs generated in the holes, and to partially dissolve the surface copper foil in the thickness direction in a planar manner. The printed wiring board according to claim 7, wherein a copper clad board having a relative dielectric constant is used.