JP2002046125A - Method for manufacturing copper foil with base reinforcing b-stage resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a copper foil with a base reinforcing B-stage resin not having a precipitation of an inorganic filler and good adhesive force of the foil even by a large filler amount in a resin composition compounded by the filler. SOLUTION: The method for manufacturing the copper foil with the base reinforcing B-stage resin comprises the steps of adhering a composition obtained by compounding (a) a functional cyanic ester compound of 100 pts.wt. with (b) an epoxy resin of a liquid state at an ambient temperature of 50 to 10,000 pts.wt. and uniformly compounding an insulating inorganic filler having a relative dielectric constant of 50 or more at an ambient temperature and a specific surface area of 0.30 to 1.00 m2/g of 10 to 99 wt.% or suitably 80 to 95 wt.% with a resin composition containing a heat curing catalyst of 0.005 to 10 pts.wt. as an indispensable component with a component (a+b) of 100 pts.wt., to both surfaces of a fiber cloth base as a heat curing resin to one side surface of a thermoplastic film, as the B-stage, disposing the B-stage so that the resin is directed toward the base side, releasing the thermoplastic film of the one side surface, then disposing the copper foil, adhering by heating and pressurizing to form the copper foil with the base reinforcing B-stage resin, and preparing a high density printed circuit board by using the foil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a copper foil with a B-stage resin using a resin composition containing an insulating inorganic filler, particularly a large amount of a filler. The printed wiring board using the resin-coated copper foil obtained by the manufacturing method of the present invention has a high relative dielectric constant, and in particular, the printed wiring board obtained by drilling with a carbon dioxide gas laser is a high-density small printed wiring board. As a board, a semiconductor chip is mounted, and it is mainly used for a small and lightweight semiconductor plastic package, a delay element, and the like.

[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. This printed wiring board
It has been proposed to add a large amount of an inorganic filler in order to improve heat dissipation and the like and to obtain a high dielectric constant. However, when added in a large amount of 80% by weight or more, defects such as poor adhesion to the copper foil and poor dispersibility of the inorganic filler were observed. Also, when preparing a prepreg using a base material such as a glass cloth base material, if the amount of the inorganic filler in the resin composition is too large, the varnish is continuously impregnated and dried,
Adhesion of the resin composition on the surface of the glass cloth base material becomes uneven,
A good prepreg could not be prepared due to cracking and unevenness of the resin layer. In addition, there was no case in which a large amount of an inorganic filler was added because of its large specific gravity and settling when dispersed in a varnish. In each proposal, the amount of the inorganic filler added in the example was 75.
The limit was about weight%. Furthermore, when a large amount of an inorganic filler is used, the obtained copper-clad laminate is brittle, and furthermore, when a copper foil is adhered, the adhesive strength with the copper foil is extremely low, and it is difficult to use it as a printed wiring board. Was. Even when the amount of the inorganic filler is small, when the nonwoven fabric is impregnated and dried, the resin composition containing the inorganic filler does not uniformly adhere to the gaps of the nonwoven fabric, the resin flow is large at the time of lamination molding, and the uniformity of the location of the laminated plate is increased. Was not good.

[0003] Further, as disclosed in JP-A-9-12742, a high specific gravity obtained by mixing a thermosetting resin and an inorganic powder having a dielectric constant of 50 or more without using a glass cloth substrate. In order to form the dielectric film into a film, the viscosity of the resin is high, and the upper limit of the additive amount of the inorganic filler is about 60% by weight. When preparing a copper foil with a resin, a resin composition layer is continuously attached to the copper foil, and heated and dried to form a B stage, but the obtained copper foil with a resin does not have a base material attached thereto, The overall strength in the case of lamination molding is weak, which is just one step for printed wiring boards for mobile phones, and the dimensional shrinkage during lamination molding is large, making it difficult to use them for high density printed wiring boards.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems. Even if the amount of the inorganic filler is large, the adhesive force between the copper foil and the thermosetting resin is high, the dimensional shrinkage is small, An object of the present invention is to provide a method for producing a copper foil with a base-reinforced B-stage thermosetting resin suitable for producing a printed wiring board having high strength, excellent carbon dioxide laser drilling properties, and good hole connection reliability.

[0005]

According to the present invention, a resin composition comprising 10 to 99% by weight of an insulating inorganic filler powder mixed in a thermosetting resin is coated on one surface of a thermoplastic film and dried. B
Create a resin composition layer as a stage, arrange it on both sides of the fiber cloth substrate so that the resin layer faces the substrate side, peel off one thermoplastic film, and place a copper foil on this peeled surface The present invention provides a method for producing a copper foil with a base-reinforced B-stage resin, wherein the base material, the resin layer and the copper foil are integrated under heat and pressure. The copper foil with resin obtained by the production method of the present invention is suitable for being used as a copper-clad board and then as a printed wiring board. Further, as a thermosetting resin, (a) a polyfunctional cyanate compound, 100 parts by weight of the cyanate ester prepolymer, (b) 50 to 10,000 parts by weight of a liquid epoxy resin at room temperature, This (a +
b) For 100 parts by weight, by using a resin composition containing 0.005 to 10 parts by weight of a thermosetting catalyst as an essential component, heat resistance, excellent electrical insulation after moisture absorption, etc. Things are obtained. It was prepared by uniformly mixing an insulating inorganic filler powder having a BET specific surface area of 0.30 to 1.00 m ² / g and an average particle diameter of 4 to 30 μm to 10 to 99% by weight, preferably 80 to 95% by weight. Preferably, a copper foil with a high dielectric constant resin having a relative dielectric constant of 20 or more is used, and this is used as a printed wiring board. This printed wiring board has small dimensional shrinkage during lamination molding, excellent copper foil adhesive strength, strong strength, high heat resistance, high relative dielectric constant, and excellent small-diameter drilling by carbon dioxide gas laser, Excellent hole connection reliability.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a film obtained by adhering a thermosetting resin composition layer containing 10 to 99% by weight of an insulating inorganic filler on both sides of a fiber cloth substrate to one surface of a thermoplastic film. The present invention provides a method for producing a copper foil with a base-reinforced B-stage resin by placing a copper foil by peeling off one of the thermoplastic films and placing the copper foil on a central substrate and a copper foil under heating and pressing. . A copper-clad board is formed from the obtained copper foil with resin, holes are formed, and a circuit is formed to obtain a printed wiring board.

[0007] When a large amount of inorganic filler is added, particularly 80% by weight or more, disadvantages such as a decrease in copper foil adhesive strength are caused. Therefore, a copper-clad laminate having a large amount of an inorganic filler added has not been developed in the conventional proposal. In the present invention, in particular, the relative dielectric constant
In order to prepare a copper-clad laminate having a copper foil adhesive strength of 20 or more and a printed wiring board using the same, the average particle diameter of the inorganic filler is preferably 4 to 30 μm, and the BET specific surface area is 0.30. A generally known insulating inorganic filler powder of 〜1.00 m ² / g is used. Specifically, talc, calcined talc, wollastonite, titanium dioxide, aluminum hydroxide,
Synthetic mica, barium titanate ceramic, lead titanate ceramic, calcium titanate ceramic, strontium titanate ceramic, magnesium titanate ceramic, bismuth titanate ceramic, lead zirconate ceramic, etc. are preferably used. , Containing at least one or more of these, and / or
After sintering the seeds or more, pulverized powder is blended. By using an inorganic filler having a relative dielectric constant of 50 or more, preferably 500 or more, a copper-clad laminate having a relative dielectric constant of 20 or more can be produced. Furthermore, by using needle-like inorganic fillers together,
Mechanical strength such as bending strength can be further improved.

[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, heat resistance after moisture absorption, and the like, a polyfunctional cyanate resin is preferably used. The amount used is preferably (a) a polyfunctional cyanate compound, 100 parts by weight of the cyanate ester prepolymer, and (b) 50 to 10,000 parts by weight of a liquid epoxy resin at room temperature. (a
+ b) A thermosetting resin composition containing, as an essential component, a resin composition in which 0.005 to 10 parts by weight of a thermosetting catalyst is added to 100 parts by weight of the 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. Generally, it is used after being dissolved 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. However, when the curing speed is slow and the workability and economic efficiency are poor, a known thermosetting catalyst is used for the thermosetting resin 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 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, a raikai machine and a homomixer are used. In addition, a solvent is added so that the viscosity is suitable for the processing method.

As a substrate, an organic or inorganic fiber cloth substrate is used. Although there is no particular limitation on the type, as the organic fiber cloth, a nonwoven fabric or a woven fabric such as a liquid crystal polyester fiber, a polybenzazole fiber, and a wholly aromatic polyamide fiber is preferably used. In particular, a liquid crystal polyester nonwoven fabric is preferably used from the viewpoint of drilling holes such as a mechanical drill and a carbon dioxide laser. In the case of a nonwoven fabric, a binder is attached to connect the fibers, or pulp and fibers are mixed, and the pulp is heated and melted at a temperature of about 300 ° C. and used as a binder instead of JP-A-11-255908. Non-woven fabrics and the like can be used. The amount of the binder is not particularly limited, but is preferably 3 to 8% by weight in order to maintain the strength of the nonwoven fabric. As the inorganic fiber cloth, a glass fiber woven cloth or nonwoven cloth having a general circular cross section, or a ceramic fiber woven cloth or nonwoven cloth having a relative permittivity of preferably 50 or more is used. If a circular glass fiber cloth is used, the thickness cannot be reduced, and when a large amount of an inorganic filler is used, defects such as poor impregnation may occur.Preferably, glass fibers having a flat cross section are used. The oblateness expressed by the major axis / minor axis of the cross section is 3.1 / 1 to 5/1, the flat glass fiber having a converted fiber diameter of 5 to 17 μm is 90% by weight or more, and the thickness is 100μ.
m, preferably 50 μm or less, is used as the substrate. Further, it is preferable to use ceramic fibers having a relative dielectric constant of 50 or more, preferably 500 or more. When using a large amount of inorganic filler, from the point of impregnation,
Non-woven fabrics are preferred.

A method of forming a prepreg by forming a resin layer on both surfaces of a base material is to prepare a varnish by adding an insulating inorganic filler to a resin composition and, if necessary, adding a solvent.
One side of the thermoplastic film is applied by knife coating or the like, heated and dried to form a B-stage resin sheet, which is arranged on both sides of the base material such that the resin layer faces the base material side,
The thermoplastic film is peeled off from one side, a copper foil is arranged, and heated, pressed with a pressure roll or the like, and integrated to form a copper foil with a base-reinforced B-stage resin.

The prepreg of the present invention may be cured by heating as it is, or the substrate-reinforced B-stage copper foil may be placed on both surfaces of the inner layer plate by peeling off the thermoplastic film used as the release film, and then heated. The laminate is formed under pressure to form a copper-clad laminate, which is a printed wiring board. The copper foil is not particularly limited, but an electrolytic copper foil having a thickness of 3 to 35 μm is preferably used. Also, a copper foil having a shiny surface subjected to nickel metal treatment or nickel alloy treatment can be used. The lamination molding conditions of the copper clad board used in the present invention are generally a temperature of 150 to 250.
° C, pressure 5-50 kgf / cm ² , time is 1-5 hours. Further, it is preferable to carry out lamination molding under vacuum.

When a through hole and / or a blind via hole is made in a copper-clad plate obtained by using the copper foil with a base-reinforced B-stage resin, a mechanical drill can be used, but an inorganic filler is not used. If the amount is large, drill wear and the like are large, so that drilling with a laser is preferable. Hole diameter 80
In order to form holes of up to 180 μm, a carbon dioxide laser is preferred from the viewpoint of processing speed and the like.

The method of drilling is not particularly limited, but a through hole and / or a blind via hole is formed by arranging a drilling auxiliary layer on a copper-clad laminate and directly irradiating a high-energy carbon dioxide laser. Can be easily done. When a through hole and / or a blind via hole is opened, copper foil burrs remain around the hole. Although it is possible to remove this by polishing or the like, there is a large possibility that burrs will remain, and it is preferable that the copper foil burrs generated around a part of the copper foil on the surface layer of the copper foil and the periphery of the hole be removed with a chemical solution. After etching and removing to a thickness of up to 7 μm, preferably 3 to 5 μm and copper plating, a circuit is formed on the front and back surfaces to obtain a printed wiring board. When making a multilayer laminate,
A copper surface treatment, a prepreg and a copper foil are arranged on at least one side of the printed wiring board, and a multilayer copper-clad board obtained by lamination molding is used, and preferably, the inner and outer layer copper foils are finally connected to the front and back sides. Through holes and / or blind via holes are formed, a part of the copper foil on the front and back is removed by etching with a chemical solution, through-hole plating, blind via hole copper plating,
After the front and back circuits are formed, if necessary, the circuit is covered with a plating resist and plated with a noble metal to obtain a printed wiring board.

For drilling, use excimer laser, YA
G laser, carbon dioxide laser, mechanical drill, etc.
Although a generally known perforation method can be used, it is preferable to use a carbon dioxide gas laser from the viewpoint of workability, perforation speed and the like. Of course, it is also possible to use a combination of the drilling methods.

The through hole and / or the blind via hole having a hole diameter of 20 μm or more and 180 μm or less are generally formed by laser. Pore diameter 20μm or more, less than 80μm pores, excimer laser, YAG laser is preferred, those with a pore diameter of 80μm or more and 180μm or less, metal oxide treatment or chemical treatment on the copper foil surface, or melting point 900 ℃ or more And a paint containing 3 to 97 vol% of one or more of metal compound powder, carbon powder, or metal powder having a binding energy of 300 kJ / mol or more,
Alternatively, a sheet-like material, preferably, having a total thickness
It is arranged on a copper foil surface with a thickness of 30 to 200 μm, and the output of a carbon dioxide laser is preferably formed by directly irradiating a carbon dioxide laser having an energy selected from 20 to 60 mJ to form through holes and / or blind via holes. . In drilling, the copper foil is used as a drilling auxiliary layer by applying a nickel metal treatment or a nickel alloy treatment to the shiny surface of the copper foil, and a carbon dioxide gas laser of preferably 5 to 60 mJ is applied from above. Direct irradiation can form a through-hole and / or a blind via hole.

Further, a chemical solution treatment (for example, CZ treatment, MEC Co., Ltd.) can be applied to the surface of the copper foil to form holes similarly. After processing, the surface of the copper foil can be deburred by mechanical polishing, but in order to completely remove the deburr, preferably both surfaces of the copper foil are etched in a plane and the original metal foil is etched. By removing a part of the thickness by etching, it is preferable to also remove the copper foil burr protruding in the hole part by etching, and since the copper foil becomes thinner, it was obtained by plating up with subsequent metal plating. A high-density printed wiring board can be produced without generating defects such as short-circuits and broken patterns in the formation of fine wire circuits on the front and back copper foils. 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 50% by volume or more by copper plating. In addition, in the case of the last through hole, by connecting the copper foil on 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. When a hole having a hole diameter of more than 180 μm is formed, a mechanical drill is preferably 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 higher at 0 ° C. or higher, generally known metal compounds can be used. Specifically, as the oxide, titanias such as titanium oxide,
Magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, zinc oxide such as manganese dioxide and zinc oxide, silicon dioxide, aluminum oxide, rare earth oxide, and cobalt oxide such as cobalt oxide Substances, tin oxides such as tin oxide, tungsten oxides such as tungsten oxide, and the like. As a non-oxide,
Generally known materials such as silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, and rare earth oxysulfides can be used. 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 powder may be mentioned, and further, silver, aluminum, bismuth, cobalt,
Metal powder of a simple substance such as copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc, or an alloy thereof is used. These may be used alone or in combination of two or more. The average particle size is not particularly limited, but is preferably 1 μm or less.

Since the molecules are dissociated or melted and scattered by the irradiation of the carbon dioxide laser, the metal adheres to the hole walls and the like, and does not adversely affect the semiconductor chip and the hole wall adhesion. 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 of the auxiliary material is not particularly limited, but when kneaded, applied to the copper foil surface and dried,
Alternatively, in the case of a sheet shape, a material that does not lose peeling 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 using 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.

On the back surface of the copper clad plate, a back-up sheet in which a water-soluble resin is adhered on a metal plate is used on the back surface in order to avoid damage to the table of the carbon dioxide laser when a through hole is formed. Is preferred.

The auxiliary material is applied as a coating film on the surface of the copper foil or is applied on a thermoplastic film to form a sheet. When heating the sheet to the copper foil surface, laminating under pressure, the auxiliary material, the backup sheet together with the applied resin layer toward the copper foil surface, with a roll, the temperature is generally 40 ~ 150 ℃, preferably 60 ~ 120 ℃ In general, lamination is performed under a linear pressure of 0.5 to 20 kgf / cm, preferably 1 to 10 kgf / cm, and the resin layer is melted and brought into close contact with the copper foil surface. The choice of temperature depends on the melting point of the water-soluble resin used, and also depends on the linear pressure and the laminating speed.
Laminate at 5-20 ° C higher temperature. 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.

The carbon dioxide laser is preferably output at 5 to 60 m.
When a hole is formed by J irradiation, burrs are generated around the hole. This is not a particular problem in a double-sided copper-clad laminate with a thin copper foil, and the resin remaining on the copper foil surface is removed by gas phase or liquid phase treatment, and the inside of the hole is directly plated with copper. More than 50% by volume of the inside of the hole can be plated with copper, and the surface layer can be plated at the same time to reduce the thickness of the copper foil to 18 μm or less. However, preferably, the etching liquid is sprayed or sucked through the holes to dissolve and remove the overhanging copper foil burrs, and at the same time, the thickness of the surface copper foil is 2 to 7 μm, preferably 3 μm.
Etch to a thickness of about 5 μm and perform copper plating. In this case, etching with a chemical solution is better than mechanical polishing.
It is preferable from the viewpoints of removing burrs from the holes and dimensional change due to polishing.

The method of etching and removing copper burrs generated in the holes according to the present invention is not particularly limited. For example, Japanese Patent Application Laid-Open Nos. 02-22887, 02-22896, 02-25089, and 02-2
5090, 02-59337, 02-60189, 02-166789, 03-25
995, 03-60183, 03-94491, 04-199592, 04-263
No. 488 discloses a method of dissolving and removing a metal surface with a chemical (referred to as a SUEP method). The etching speed 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. The output is preferably made by drilling a hole in the copper foil at 20-60 mJ / pulse. 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 10 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, 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, the output can be selected from 5 to 35 mJ. 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 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 filling with 50% by volume or more by copper plating, it is preferably filled with 50% by volume or more, more preferably 90% by volume or more. However, if the inside of the hole is filled with a longer plating time, the workability is poor, and a method using a pulse plating additive (manufactured by Nippon Rironal Co., Ltd.) suitable for filling the hole is preferably used.

[0035]

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
Melt 1,000 parts of A-1) at 150 ° C and stir for 4 hours
Reaction, prepolymer of average molecular weight 1,900 (component A-
2) was obtained. As a liquid epoxy resin at room temperature,
Enol A type epoxy resin (trade name: Epicoat 828, oil
Shell Epoxy Co., Ltd., component B-1), bisphenol
F-type epoxy resin (trade name: EXA830LVP, Dainippon Ink)
Chemical Industry Co., Ltd., component B-2), novolak type epoxy tree
Fat (trade name: DEN431, manufactured by Dow Chemical Co., Ltd., ingredient B-3),
Cresol novolak epoxy resin (Product name: ESCN220
F, Sumitomo Chemical Co., Ltd., component B-4)
Mediate iron acetylacetone (component C-1), 2-ethyl-4-
Methyl imidazole (component C-2), and as an additive,
Epoxy silane coupling agent (trade name: A-187, Nippon Yu
Nika Corporation, component D-1), dicyandiamide (component E-1)
Was mixed to form a varnish. As an insulating inorganic filler,
Barium titanate-based ceramic (relative dielectric constant at 1 MHz at room temperature)
Rate: 2,010, BET specific surface area 0.41m ^Two/ g, component F-1
), Bismuth titanate ceramics (relative dielectric constant at room temperature)
Rate: 733, BET specific surface area 0.52m^Two/ g, component F-2),
Barium titanate-calcium stannate ceramic (room temperature
Dielectric constant at 5,020, BET specific surface area 0.45m^Two/ g, ingredient F
-3), titanium dioxide-based ceramics (specific induction at room temperature)
Electricity 30, BET specific surface area 0.92m^Two/ g, component F-4)
Mix as shown in Table 1
Knead and add a small amount of methyl ethyl ketone for those with high viscosity.
To an appropriate viscous viscosity to be applied and applied.
A varnish with very slow settling of the filler was used. Thick this varnish
50 μm polyethylene terephthalate (PET) film
Apply and dry to a thickness of 40-50 μm on one side continuously
And 170 ℃, 20kgf / cm^Two5 to 20mm resin flow in 5 minutes
Create resin sheet Z with B stage so that
Was.

This varnish was prepared with a fiber 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
Nonwoven fabric G obtained by attaching and drying at 150 ° C, aspect ratio
Nonwoven fabric H with a weight per unit area of 15 g / m ² , obtained by attaching a binder and a silane coupling agent to high flat glass fiber having an area ratio of 92%, a converted fiber diameter of 10 μm, and a length of 13 μm in the same manner. Non-woven fabric I prepared in the same manner as above using ceramic fibers having a diameter of 11 μm, a length of 14 μm, and a relative dielectric constant of 1,320, a thickness of 20 μm, and a weight of 17
g / m ² glass woven fabric J, on both sides, the resin layer of resin sheet Z was arranged so as to face the substrate side, and was laminated and integrated with a roll of 5 kgf / cm at 100 ° C. to obtain a B-stage prepreg. Then, it was cut to 530x530mm.

The PET film of the B-stage prepreg was peeled off and three sheets were used. A general electrolytic copper foil (JTC-LP, manufactured by Japan Energy Co., Ltd.) having a thickness of 12 μm was placed on both sides of the PET film at 200 ° C. and 20 kgf. Laminate molding was performed for 2 hours under a vacuum of 30 mmHg or less at 30 mmHg / cm ² to obtain a double-sided copper-clad laminate. In addition, using two of these, a circuit was formed on both sides of a 0.2 mm thick, 12 μm copper foil double-sided copper-clad laminate (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: CCL-HL830), and placed on both sides. To form a four-layer multilayer plate.

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 mixed with stirring.
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 multilayer copper-clad laminate, the backup sheet Q on the lower side, placed so that the resin surface faces the copper foil side, 100 ° C., laminated at 5 kgf / cm, the hole diameter 100 μm In a 20 mm square, 144 holes were directly irradiated with a carbon dioxide gas laser at an output of 30 mJ for 4 shots, a through hole of 70 blocks was made, SUEP treatment was performed, and the surface copper foil was etched until it became 3 μm. Burrs around the holes were also dissolved and removed. Copper plating was applied to 15 μm. Form a circuit (line / space = 50/50 μm) and solder ball lands on the front and back by the existing method, cover with a plating resist except for at least the semiconductor chip mounting part, pad part, solder ball pad part, nickel And gold plating to make a printed wiring board. The evaluation results are shown in Tables 3 and 4.

Comparative Example 1 2,000 parts of an epoxy resin (trade name: Epikote 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 varnish G was obtained by mixing and uniformly dispersing (this solid is referred to as “Component B-5”). The titanium dioxide shellac powder (BET specific surface area 1.26
m2 / g, relative dielectric constant 25, component F-5), and the mixture was mixed well with a homomixer.
It was continuously applied to a μm electrolytic copper foil and dried to prepare a B-stage resin-coated copper foil. Two sheets of this were used, facing each other, and laminated and formed under a vacuum of 180 ° C., 30 kgf / cm ² , and 30 mmHg or less to prepare a double-sided copper-clad board. In addition, two sheets were used, arranged on both sides of the inner layer plate of Example 1, and similarly laminated and formed into a multilayer board. Drilling was performed to produce a printed wiring board. The evaluation results are shown in Tables 3 and 4.

COMPARATIVE EXAMPLE 2 In the same manner as in Comparative Example 1, a mixed system of varnish G and titanium dioxide powder was prepared.
Weight%, and continuously impregnated in glass cloth J.
Although dried to form a prepreg, the amount of the inorganic filler was large, coating unevenness and cracking of the resin occurred, and a good prepreg could not be obtained. A place with good coating was selected, eight of these were used, and a 12 μm electrolytic copper foil was laminated on both sides, and laminated and formed under the same conditions as in Comparative Example 1 to obtain a double-sided copper-clad laminate. Physical property measurement was not possible.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

<Measurement method> 1) Void after lamination molding The copper foil of the copper clad laminate formed by lamination molding was removed by etching, and voids were visually observed. 2) Copper foil adhesive strength The adhesive strength of the copper foil of the copper-clad laminate was measured according to JIS C6481. 3) Glass transition temperature Measured by the DMA method of JIS C6481. 4) Relative permittivity Measured with an LCR meter and calculated by calculation. 5) Bending strength The bending strength was measured at a distance between supporting points of 20 mm and a width of the test piece of 20 mm. 6) Through-hole heat cycle test Prepare a plate with a thickness of about 0.3 mm, drill holes in the same way as in each example and comparative example, and create a land diameter of 300 μm in each through-hole with SUEP and copper plating. 900 holes are connected alternately on the front and back, and one cycle is performed at 260 ° C
Immersion was performed for 30 cycles from 30 seconds to room temperature for 5 minutes up to 150 cycles, and the maximum value of the rate of change in resistance was shown. 7) Insulation resistance value after pressure cooker processing A comb pattern between terminals (line / space = 50 / 50μm) was created, and the prepreg used for each was placed on top of this.
After arranging the sheets and laminating them, treat them at 121 ° C and 203kPa for a predetermined time, then perform post-treatment at 25 ° C and 60% RH for 2 hours, apply 500VDC for 60 seconds, charge, and insulate the terminals. The resistance was measured. 8) Migration resistance The test piece of the above 6) was constantly applied with 50 VDC in an atmosphere of 85 ° C. and 85% RH, and the insulation resistance between terminals was measured. 9) Bending strength Measured at a distance between supporting points of 10 mm and a width of 100 mm. 10) Content of Inorganic Filler 500 g of a prepreg was taken, the substrate weight was subtracted, and this was incinerated to calculate the inorganic filler adhesion weight. 11) Dimensional shrinkage ratio Inner plate is CCL-HL830 0.2mm, 12 manufactured by Mitsubishi Gas Chemical Co., Ltd.
50% circuits are formed on the copper foil on both sides of the double-sided copper foil board, black copper oxide treatment is applied, and 12μm electrolytic copper foil with B-stage resin is placed on both sides. Then, the dimensional shrinkage of the inner layer plate was measured.

[0047]

According to the present invention, one surface of a thermoplastic film is
10-99% by weight of insulating inorganic filler powder in thermosetting resin
A blended resin composition is applied and dried to form a B-stage resin composition layer, which is disposed on both sides of a fiber cloth substrate such that the resin layer faces the substrate side, and one thermoplastic film is formed. The present invention provides a method for producing a copper foil with a base-reinforced B-stage resin, in which a base material, a resin layer and a copper foil are integrated under heat and pressure by placing a copper foil on the separated surface. Preferably, a BET specific surface area of the insulating inorganic filler of 0.30 to 1.00 m ² / g is a thermosetting resin composition, preferably, (a) a polyfunctional cyanate ester monomer, the cyanate ester prepolymer 100 With respect to parts by weight, (b) 50 to 10,000 parts by weight of an epoxy resin liquid at room temperature is blended, and 100 parts by weight of the (a + b) component is added to a resin component containing 0.005 to 10 parts by weight of a thermosetting catalyst. A resin composition obtained by mixing uniformly to 10 to 99% by weight, preferably 80 to 95% by weight is used. According to the production method of the present invention, the base-reinforced copper foil with a B-stage resin has an extremely small settling of the inorganic filler and can form a uniform resin composition layer. The wiring board obtained was excellent in adhesion and strength to the copper foil, and excellent in heat resistance, electrical insulation after moisture absorption, and the like. Further, those having a relative permittivity of 20 or more were obtained, and useful ones as capacitors and the like were 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 F term (reference) 4F072 AB05 AB29 AD27 AD28 AD45 AE08 AF02 AF30 AG03 AG16 AG17 AG18 AG19 AG22 AJ02 AJ03 AK05 AK14 AL13 4F100 AA01A AA01C AA17 AA34 AA34H AB10 AB17D AB33D AG00B AH06AHA AK06 AK53A AK53J AL01A AL05A AL05C BA04 BA07 DE01A DE01C DG11B DG15B DH01 GB43 JA20B JB13A JB13C JG04A JG04C JL11

Claims (6)

[Claims] 1. A resin composition layer in which a thermosetting resin is blended with 10 to 99% by weight of an insulating inorganic filler powder on one surface of a thermoplastic film and dried to form a B stage. It is placed on both sides of the fiber cloth substrate so that the resin layer faces the substrate side, one thermoplastic film is peeled off, copper foil is placed on this peeled surface, and heating and pressing are performed. Base material,
Base material reinforcement B characterized by integrating a resin layer and a copper foil
Manufacturing method of copper foil with stage resin. 2. The thermosetting resin comprises: (a) a polyfunctional cyanate ester monomer; and the cyanate ester prepolymer.
For 100 parts by weight, (b) 50 to 1 liquid epoxy resin at room temperature
2. The base material according to claim 1, wherein the resin composition is obtained by mixing 0.005 to 10 parts by weight of a thermosetting catalyst with respect to 100 parts by weight of (a + b). Reinforcement B
Manufacturing method of copper foil with stage resin. 3. The insulating inorganic filler has an average particle size of 4 to 3
0 .mu.m, a BET specific surface area of 0.30~1.00m ² / g, according to claim 1 or 2 base reinforcement according B-stage resin coated copper foil, characterized in that blended with the insulative inorganic filler of 80 to 95 wt% Manufacturing method. 4. The method for producing a copper foil with a base-reinforced B-stage resin according to claim 1, wherein the relative dielectric constant of the insulating inorganic filler is 50 or more. 5. The method for producing a copper foil with a base-reinforced B-stage resin according to claim 1, wherein the fiber cloth is an aromatic polyester fiber non-woven fabric. 6. The fiber cloth is a glass fiber having a flat cross section,
The oblateness expressed by the major axis / minor axis of the cross section is 3.1 / 1 to 5/1, the cross-sectional area is 90 to 98% of the area of the rectangle circumscribing the glass fiber cross section, and the converted fiber diameter is 5 to The glass fiber non-woven fabric having a flat glass fiber having a thickness of 17 μm and containing 90% by weight or more and a thickness of 100 μm or less.
5. The method for producing a copper foil with a base-reinforced B-stage resin according to 2, 3, or 4.