JP2001028475A - Manufacture of polybenzazole fabric base-material printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic base-material printed wiring board of light weight, low rigidity and low thermal expansion factor. SOLUTION: A polybenzazole fabric is used as a base material while a multifunctional ester cyanate resin composition is preferred to be used as a thermo-setting resin, with which an insulating inorganic filler is mixed by 10-80 wt.% to provide a copper-plated laminated board. On the copper foil of it, an organic material comprising, by 3-97 vol.%, at least one kind among metal compound powder, carbon powder, and metal powder of melting-point 900 deg.C or above while coupling energy being 300 kJ/mol or above is arranged. A carbon dioxide energy selected among 20-60 mJ/pulse is directly poured on it for boring, providing a printed wiring board. Thus, a printed wiring board of high heat- resistance, low thermal expansion factor, and low rigidity which is excellent in solder's heat-resistance after moisture-absorption, anti-migration characteristics, and hole connection reliability is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a low-density printed wiring board using a copper-clad laminate of a polybenzazole fiber cloth excellent in heat resistance, electrical insulation, coefficient of thermal expansion and the like. A printed wiring board using this copper-clad laminate is lightweight and is mainly used for thin and small semiconductor plastic packages on which semiconductors are directly mounted.

[0002]

2. Description of the Related Art Conventionally, as a substrate used for a printed wiring board, glass fiber is known as an inorganic fiber.
Widely used. Although it has rigidity, it has a large coefficient of thermal expansion, and when a semiconductor chip is mounted, stress is applied to the semiconductor chip by heat treatment or the like, which causes a problem such as cracking. Furthermore, the specific gravity of glass fiber is larger than that of organic fiber, and in recent years, a lighter weight organic fiber cloth has been required for electronic devices that are becoming lighter and lighter. In order to meet this demand, a wholly aromatic polyamide fiber cloth and a liquid crystal polyester fiber cloth have been used. However, the wholly aromatic polyamide fiber cloth has problems in electrical insulation and heat resistance after moisture absorption, and the liquid crystal polyester fiber cloth has only one step in heat resistance, coefficient of thermal expansion and the like. In addition, the organic fiber cloth and the polybenzazole fiber cloth had a drawback such that when drilled with a mechanical drill due to their strength, the cuts were poor and fluff remained on the hole walls. In addition, the hole wall by a mechanical drill is generally 200 μm or more, and 150 μm or more.
It was not possible to directly irradiate holes of less than m in the copper clad board by directly irradiating a carbon dioxide laser.

[0003]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a high-density printed wiring board excellent in heat resistance, electrical insulation and coefficient of thermal expansion, which solves the above problems.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a printed circuit board which is particularly small and lightweight. By using a nonwoven fabric or woven fabric of polybenzazole fiber as the base material, a printed wiring board that is lighter in weight, lower in rigidity and lower in thermal expansion coefficient than glass fiber cloth can be produced. In drilling, a laser drill is suitable because a mechanical drill generates fluff on the hole wall. Excimer laser, YAG laser, and carbon dioxide laser can be used as the laser. But excimer laser, YAG
Lasers are disadvantageous in processing speed, workability and cost. Preferably, a carbon dioxide laser is used with an energy of 20.
Metal oxide treatment or chemical treatment on the surface of the copper-clad laminate in the range of ６０60 mJ / pulse, or one of metal compound powder, carbon powder and metal powder having a melting point of 900 ° C. or more and a binding energy of 300 kJ / mol or more. A composition comprising an organic substance, preferably a resin, containing 3 to 97 vol% of one or more species is disposed, and a hole is formed by irradiating a carbon dioxide laser. By doing so, a printed wiring board having excellent workability and workability and good hole quality can be produced.

Further, after drilling holes, burrs of the copper foil are generated around the holes, and it is necessary to remove the burrs. Removal of burrs can also be performed by mechanical polishing, but it is difficult to completely remove them, and removal with a chemical solution is optimal. Simultaneously with this deburring, the front and back copper foils are partially removed in the thickness direction so that the thickness is preferably 3 to 5 μm.

As an insulating layer of a copper-clad laminate of a polybenzazole fiber cloth base thermosetting resin, a polyfunctional cyanate ester and the cyanate ester prepolymer are essential components, and the glass transition temperature after curing is 150. By using a thermosetting resin having a heat resistance of not less than ° C., the hole wall shape at the time of laser processing is improved. Furthermore, since the space between the hole walls becomes narrower and the line / space becomes narrower, the use of this thermosetting resin provides excellent migration resistance, heat resistance after pressure cooker treatment, etc., and high density printed wiring. It is suitable as a resin for plates. In addition, by adding a filler to the resin, it is possible to further improve the shape of the hole wall by drilling the carbon dioxide laser,
A high-density printed wiring board having extremely high reliability can be manufactured. In addition, the printed wiring board is produced not only by using a single-sided and double-sided copper-clad laminate, but also by using a multilayer board using the same base material and resin composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention uses a nonwoven fabric or woven fabric of polybenzazole fiber as a base material, impregnates with a thermosetting resin composition, and forms a B-stage prepreg obtained by drying. The present invention relates to a method for manufacturing a printed wiring board produced using a copper-clad laminate obtained by the above method. Further, the thermosetting resin composition contains 10 to 80% by weight of an insulating inorganic filler.
%, Preferably 20 to 70% by weight, and uniformly mixed. Further, as a thermosetting resin, by using a polyfunctional cyanate ester and the cyanate ester prepolymer as an essential component, a material having excellent hole connection reliability when a hole is formed by a carbon dioxide laser can be obtained. The heat resistance and rigidity of the laminate itself of the printed wiring board were improved, and a laminate excellent in electrical insulation after heat absorption, heat resistance, migration resistance and the like was obtained.

[0008] The polybenzazole fiber used in the present invention is a fiber obtained from a polybenzazole polymer. Polybenzazole refers to polybenzoxazole homopolymers, polybenzothiazole homopolymers and their random, sequential or block copolymers. Specifically, Wolfe et al.'S "Liquid Crystallin
e Polymer Compositions, Process and Products '' US
Patent 4, 703,103 (October 27, 1987), `` Liquid Crys
talline Polymer Compositions, Process and Product
s '' US Patent 4,533,692 (August 6, 1985), `` Liquid
Crystalline Poly (2,6-Benzothriazole) Compositions,
Process and Products '' USPatent 4,533,724 (August
6, 1985), `` Liquid Crystalline Polymer Compositio
ns, Process and Products '' USPatent 4,533,693 (Aug
ust 6, 1985), Evers's `` Thermooxidetively Stable Ar
ticulated p-Benzobisoxazole and p-Benzobisthiazole
Polymers '' USPatent $, 359,567 (November 16, 198
2), Thai et al.'S `` Method for making Heterocyclic Block
Copolymer "US Patent 4,578,432 (March 25, 1986) and the like are used.

The structural unit contained in the polybenzazole polymer is preferably selected from a lyotropic liquid crystal polymer, and the monomer unit is composed of a monomer unit selected from the following structural formulas: And a monomer unit selected from the following structural formulas and Chemical Formulas 1 to 3.

[0010]

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image Suitable solvents for forming the polybenzazole polymer dope include cresol and non-oxidizing acids that can dissolve the polymer. Suitable acid solvents include
Examples thereof include polyphosphoric acid, methanesulfonic acid and high-concentration sulfuric acid or a mixture thereof, and more preferable examples include polyphosphoric acid and methanesulfonic acid.

[0011] The polymer concentration of the solution is preferably at least about 7% by weight. More preferably, it is at least 10 to 14% by weight.

[0012] Suitable polymers, copolymers or dopes are synthesized by known methods. For example, Wolf et al.
S, Patent 4,533,693, US Patent 4,772,678 by Sybert et al.
The method of Harris et al., US Patent 4,847,350 is used. Polybenzazole polymers are available from Gregoly et al.
In Patent 5,089,591, it is possible to increase the molecular weight at a high reaction rate under a relatively high temperature and high shear condition in a dehydrating acid solvent.

In the present invention, the polybenzazole fiber is made into a woven fabric by using the fiber as it is as a yarn. Further, the nonwoven fabric may be cut into a predetermined length and used as a nonwoven fabric by a known method such as a wet method or a dry method.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used. Specific examples include an epoxy resin, a polyfunctional cyanate ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, and an unsaturated group-containing polyphenylene ether resin. Are used in combination. A polyfunctional cyanate resin composition is preferred in terms of moisture resistance, migration resistance, electrical properties after moisture absorption, and the like. The glass transition temperature is
It is preferable that various resins be mixed and cured to have a temperature of 150 ° C. or higher from the viewpoint of the shape of the hole wall.

The polyfunctional cyanate compound which is a preferred thermosetting resin component of the present invention is a compound having two or more cyanato groups in the 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-cy (Anatophenyl) 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, a generally known epoxy resin can be used. Specifically, liquid or solid bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, alicyclic epoxy resin; butadiene, pentadiene, vinylcyclohexene, dicyclopentyl ether, etc. And polyglycidyl compounds obtained by reacting a polyol, a hydroxyl-containing silicone resin with an epohalohydrin, and the like. These may be used alone or in combination of two or more.

As the polyimide resin, generally known ones can be used. Specific examples include a reaction product of a polyfunctional maleimide and a polyamine, and a polyimide having a terminal triple bond described in JP-B-57-005406.

These thermosetting resins may be used alone, but it is preferable to use them in an appropriate combination in consideration of the balance of properties.

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 organic fillers, dyes,
Pigments, thickeners, lubricants, defoamers, dispersants, leveling agents,
Various additives such as a photosensitizer, a flame retardant, a brightener, a polymerization inhibitor, and a thixotropy-imparting agent are used in an appropriate combination as required. If necessary, the compound having a reactive group is appropriately blended with a curing agent and a catalyst. When a hole is formed by a carbon dioxide gas laser, it is preferable to mix a black dye and a pigment with the resin from the viewpoint of the hole wall shape, the hole quality and the like.

The thermosetting resin composition of the present invention can be cured by heating itself, but has a low curing rate and is inferior in workability and economical efficiency. Can be used. The amount used is 0.005 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the thermosetting resin.

As the inorganic insulating filler, generally known ones can be used. Specifically, silicas such as natural silica, calcined silica, and amorphous silica; white carbon, titanium white, aerosil, clay, talc,
Examples include wollastonite, natural mica, synthetic mica, kaolin, magnesia, alumina, perlite, aluminum hydroxide, and magnesium hydroxide. The amount added is 10 to 80% by weight, preferably 20 to 70% by weight. The particle diameter is preferably 1 μm or less.

As the outermost copper foil, generally known ones can be used. Preferably, an electrolytic copper foil or the like having a thickness of 3 to 12 μm is used. As the copper foil of the inner layer, an electrolytic copper foil of 9 to 70 μm or the like is preferably used.

The method for producing the copper-clad laminate is not particularly limited. For example, first, the polybenzazole fiber cloth base material is impregnated with a thermosetting resin composition and dried to form a B stage.
Preferably, the prepreg is prepared so that the content of the resin composition is 40 to 70 wt%. Next, a predetermined number of the prepregs are used, a copper foil is arranged on at least one side, and lamination molding is performed under heating and pressure to obtain a copper-clad laminate. Of course, besides copper, its alloy, nickel foil and the like can be used, but electrolytic copper foil is most suitable. The same applies to a multilayer board obtained by forming a circuit on this copper-clad laminate, subjecting it to a surface treatment if necessary, and laminating and molding using the same prepreg.

When a through-hole for a through-hole and a hole for a blind hole are made in the copper-clad laminate of polybenzazole fiber cloth base material, it is preferable to use a laser. Specifically, generally known lasers such as a carbon dioxide laser and an excimer laser or a YAG laser can be used although the processing speed is low. However, a carbon dioxide laser is preferred in terms of workability and economy. When drilling with a carbon dioxide gas laser, on the copper foil surface at the hole formation position on the surface irradiated with the laser,
Metal compound powder, carbon powder, arrange a coating film or sheet made of a resin composition containing one or more of metal powder, or perform metal oxide treatment, chemical solution treatment on the copper surface,
By directly irradiating a carbon dioxide laser squeezed to a target diameter, the copper foil on the front surface or the copper foil on the rear surface is drilled. As the backup sheet, it is preferable to use a sheet having a resin layer on a metal plate having a glossy surface, in order to prevent deformation of the back surface hole due to reflection of the penetrated carbon dioxide laser. In addition, a generally known method such as a method in which the surface metal foil is removed by etching in advance and a hole is formed by irradiating a carbon dioxide gas laser may be used. In the case of a blind via, desmear processing is generally performed before copper plating. Also, in the case of a through hole, desmearing is preferably performed when the copper foil is exposed in the hole. A known resin removal treatment such as a plasma treatment can also be used.

The output of the carbon dioxide gas laser is not particularly limited. Preferably, one energy of an output of 20 to 60 mJ / pulse is selected, and several pulses are irradiated to form through holes and via holes. In this case, it is possible to perform processing by changing the energy after irradiating with high energy first. When a hole is drilled, burrs are generated around the hole. When the copper foil is thin, burrs are reduced by subsequent soft etching or the like, but when the copper foil is thick, it is preferable to remove the burrs in order to improve reliability. Therefore, after the carbon dioxide laser irradiation, both surfaces of the copper foil are etched two-dimensionally, and the original copper foil is partially etched away in the thickness direction, thereby simultaneously removing burrs by etching. The obtained copper foil is suitable for forming a fine pattern, and the copper foil on both sides around the hole suitable for a high-density printed wiring board has a through hole for through-hole plating and / or
Alternatively, a via hole is formed.

In the present invention, the surface of the copper foil to be drilled by directly irradiating a carbon dioxide laser is subjected to metal oxide treatment or chemical treatment, or one or more of metal compound powder, carbon powder and metal powder. Is used for direct drilling of copper foil with carbon dioxide laser. Metal oxide powder has a melting point of 900 ° C or higher and a binding energy of 300
A powder of a metal compound of kJ / mol or more is used. Specifically, oxides include titanias such as titanium oxide; magnesias such as magnesium oxide; iron oxides such as iron oxide; nickel oxides such as nickel oxide; zinc oxides such as zinc oxide. Tin oxides such as silicon dioxide, manganese dioxide, aluminum oxide, rare earth oxides and tin oxide; and tungsten oxides such as tungsten oxide. Examples of the non-oxide include generally known materials such as silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, and barium sulfate.
In addition, carbons can also be used. Further, a simple substance such as silver, aluminum, bismuth, cobalt, copper, iron, manganese, molybdenum, nickel, tin, itanium or zinc, or an alloy thereof is used. These are used alone or in combination of two or more. The average particle size is not particularly limited, but is preferably 1 μm or less. The use amount is not particularly limited, but 3 to 97 vol% is used. These are used by being blended with an organic substance, particularly a resin composition. The resin composition is preferably a water-soluble resin also from the viewpoint of removing residue after laser processing. There is no particular limitation on the water-soluble resin, but when kneaded and applied to the surface of the copper foil and dried, or when formed into a sheet, a resin having no peeling-off is selected and used. For example, generally known materials such as polyvinyl alcohol, polyester, polyether, starch and the like can be mentioned.

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 solvent in a kneader or the like, and extruded into a thermoplastic film into a sheet. A method of adhering, dissolving the water-soluble resin in water, adding the above powder to this, and using a homogeneously stirred mixture, apply it to a thermoplastic film as a paint and dry to form a coat or directly A method of coating and drying a copper foil to form a coating film is used. The thickness is not particularly limited, but is preferably 30 to 100 μm in thickness of the coating film. When attached to a film, it is preferably a sheet having a total thickness of 30 to 200 μm. In the case of a sheet, it is preferable that the resin layer is disposed on the copper foil side and laminated under heat and pressure.

The backup sheet is preferably used for drilling through holes by disposing the water-soluble resin layer on the back surface of the copper-clad board and placing a metal plate on the outside thereof. It is preferable to use the water-soluble resin by bonding it to a copper foil. Examples of the metal oxide treatment used in the present invention include generally known treatments. Specifically, black copper oxide treatment, MM treatment (MacDarmid
Is used. Examples of the chemical treatment include CZ treatment (Mec).

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). Preferably, the etching rate is 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 copper clad board of the present invention can be processed by an excimer laser or a YAG laser. Excimer lasers are generally 248-308n
m, YAG laser is preferably used at a wavelength of 351 to 355 nm.

[0032]

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 and 2 900 parts of 2,2-bis (4-cyanatophenyl) propane,
100 parts of (maleimidophenyl) methane are melted at 150 ° C,
The mixture was reacted for 4 hours with stirring to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. Add bisphenol A type epoxy resin (trade name: Epicoat 1001, Yuka Shell Epoxy Co., Ltd.)
) And 600 parts of a cresol novolac type epoxy resin (trade name: ESCN-220F, manufactured by Sumitomo Chemical Co., Ltd.) were uniformly mixed and dissolved. Further, as a catalyst, zinc octylate 0.4
Parts, melt-mix, and add an inorganic insulating filler (trade name: calcined talc, average particle size 0.4 μm, Nippon Talc Co., Ltd.)
500 parts) and 8 parts of a black pigment were added and uniformly stirred and mixed to obtain Varnish A. This varnish A was applied to a polybenzazole fiber nonwoven fabric comprising the monomer unit of Chemical Formula 1 (Example 1, thickness 10).
0 μm, resin content 60% by weight) and woven cloth (Example 2, thickness 200 μm)
m, resin content 56% by weight), dry and gel time (at17
0 ° C) 120 seconds prepreg (prepreg B and prepreg C)
It was created. Electrodeposited copper foil having a thickness of 12 μm was placed above and below the five prepregs B and three prepregs C at 200 ° C and 20 ° C.
Laminate molding was performed for 2 hours under a vacuum of 30 mmHg or less at kgf / cm ² to obtain double-sided copper-clad laminates D and E. Separately, 800 parts of black copper oxide powder having an average particle size of 0.86 μm was added to a varnish prepared by dissolving polyvinyl alcohol powder in water, and uniformly stirred and mixed (varnish F). This was coated on the double-sided copper-clad laminate at a thickness of 30 μm and dried at 110 ° C. for 30 minutes to obtain a metal oxide content of 50% by weight.
Was formed. On the lower side, a 10 μm water-soluble polyester resin was coated on an aluminum foil with a surface gloss of 100 μm.
Place a backup sheet painted 0μm, and from above,
900 holes with a diameter of 100 μm are directly output by a carbon dioxide gas laser.
Six through-holes (shots) were made at 5 mJ / pulse to form through-holes for through-holes. The copper foil burrs around the holes were dissolved and removed by the SUEP method, and the copper foil on the surface was also dissolved to 4 μm. This plate is plated with copper by a known method at 15 μm (total thickness: 1
9 μm). A circuit (line
/ Space = 50 / 50μm), lands for solder balls, etc. are formed on the back surface, covered with a plating resist except for the semiconductor chip mounting portion, bonding pad portion, and solder ball pad portion, and nickel and gold plating are applied, and 50mm square A printed wiring board was made. A 13 mm square semiconductor chip is bonded to the semiconductor mounting part of this printed wiring board with silver paste, wire-bonded, resin-sealed, and
And H. The evaluation results are shown in Tables 1 and 2.

Example 3 1400 parts of epoxy resin (trade name: Epicoat 5045), 600 parts of epoxy resin (trade name: ESCN220F), dicyandiamide 70
And 2 parts of 2-ethyl-4-methylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide to obtain Varnish I. This was impregnated into the polybenzazole nonwoven fabric and woven fabric of Example 1 and dried to obtain a gelation time of 120 seconds and a resin amount of 5 seconds.
A prepreg J of 7% by weight (non-woven fabric) and a prepreg K of a resin amount of 50% by weight (woven fabric) were prepared. This prepreg J
Prepreg K was used on each of the outer sides, and a 3 μm electrolytic copper foil with a 35 μm carrier was placed on the outer side, and 190
℃, 20kgf / cm ² , Laminated under vacuum of 30mmHg or less,
A double-sided copper-clad laminate L was prepared. Then the carrier 35
The μm copper foil was peeled off, black copper oxide treatment was performed thereon, a through hole was formed with a carbon dioxide laser in the same manner as in Example 1, and the surface black copper oxide treated layer was washed and removed with a 5% by weight hydrochloric acid aqueous solution. Pulsed copper plating was performed to fill the inside of the hole with copper plating by 90% by volume, and thereafter, a printed wiring board was prepared in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2.

Example 4 One prepreg C of Example 1 was used.
m of electrolytic copper foil was placed and similarly laminated and formed to produce a double-sided copper-clad laminate. On this surface, the varnish F of Example 1 was applied with a thickness of 4
After coating and drying to a thickness of 0 μm, irradiate 4 shots with a CO2 laser energy of 35 mJ / pulse and apply a hole diameter of 1
A 00 μm through hole was formed. The copper foil burrs around the holes were dissolved and removed by the SUEP method, and the thickness of the surface copper foil was also dissolved to 4 μm. After copper plating with a thickness of 17 μm was applied to the whole, circuits were formed on the front and back sides, and copper oxide treatment was performed. One prepreg C of Example 1 was placed on each of the front and back sides, and 12 μm
Was placed and similarly laminated and molded to obtain a four-layer plate. On top of this, the varnish F of Example 1 was applied, dried and dried.
Irradiate 5 shots with energy of mJ to form through holes for through holes, 35 mJ / pulse 2 shots, then 10 mJ /
After irradiating a pulse one shot to form a hole for a blind via hole, the copper foil burr and surface copper
Dissolves and removes the inner layer of copper foil burrs at the same time as dissolving to μm, performs desmear treatment, attaches copper plating to 17 μm, forms circuits on the front and back, semiconductor chip mounting part,
After coating the bonding pad portion and the ball pad portion on the back surface with a plating resist, nickel plating and gold plating were performed to obtain a printed wiring board. Tables 1 and 2 show the evaluation results of the multilayer printed wiring board.

Comparative Example 1 A prepreg was prepared in the same manner as in Example 1 except that no inorganic insulating filler was used and a liquid crystal polyester fiber nonwoven fabric having a thickness of 100 μm was used as a substrate. Using this, a double-sided copper-clad laminate was prepared in the same manner as in Example 1. However, SU
The EP process was not performed, and the through-hole for a through-hole was drilled with a drill having a diameter of 200 μm to produce a printed wiring board. The evaluation results are shown in Tables 1 and 2.

Comparative Example 2 In Example 4, epicoat 5045 was used as the epoxy resin.
Varnish M using 2000 parts alone, no inorganic filler
It was created. This was impregnated into a 100 μm-thick wholly aromatic polyamide fiber nonwoven fabric and dried to obtain a prepreg having a resin amount of 60% by weight and a gel time of 115 seconds. Using this, a four-layer plate was prepared in the same manner as in Example 3. The through-hole was formed with a mechanical drill having a diameter of 200 μm, and the via-hole was similarly drilled with a carbon dioxide gas laser, subjected to desmear treatment without performing SUEP treatment, and similarly formed into a printed wiring board. The evaluation results are shown in Tables 1 and 2.

Comparative Example 3 The varnish M of Comparative Example 2 was impregnated with a 100 μm glass woven fabric and dried to obtain a prepreg N having a gelation of 110 seconds and a resin amount of 45% by weight. Using these four prepregs, 12 μm electrolytic copper foils were arranged on the front and back, and laminated and molded in the same manner as in Example 3 to prepare a double-sided copper-clad laminate. Through holes of 200 μm in total were drilled with a mechanical drill, and desmearing was performed without performing SUEP processing, to obtain a printed wiring board in the same manner as in Example 3. The evaluation results are shown in Tables 1 and 2.

[0038]

[Table 1] Note: Glass transition temperature, ° C, coefficient of thermal expansion, ppm / ° C.

[0039]

[Table 2]

<Measurement method> 1) Hole wall shape The cross section of the hole was observed, and irregularities and fluff on the wall were observed. 2) Cut and short circuit pattern In the examples and comparative examples, a board without holes was created in the same way, a comb pattern of line / space = 50 / 50μm was created, and 200 patterns were etched with a magnifying glass. Was visually observed, and the total of the broken pattern and the short-circuited pattern was shown in the molecule. 3) Glass transition temperature Measured by the DMA method. 4) Through-hole heat cycle test Create a land diameter of 200 μm for each through-hole, connect 900 holes alternately, and carry out 200 cycles at 260 ° C, solder, immersion for 30 seconds → room temperature for 5 minutes, The maximum value of the rate of change of the resistance value is shown. 5) Insulation resistance value after pressure cooker process A comb-shaped pattern between terminals (line / space = 50 / 50μm) was created, and after chemical treatment, one prepreg used was stacked on top of each other and laminated. , 121 ℃ ・ 203
What was treated for a predetermined time at kPa was post-treated for 2 hours at 25 ° C. and 60% RH, and the insulation resistance between terminals was measured 60 seconds after applying 500 VDC. 6) Migration resistance The test piece of 5) was applied at 85 ° C., 85% RH and 50 VDC, and the insulation resistance between the terminals was measured. 7) Thermal expansion coefficient Measured by TMA. Values in the vertical direction from room temperature to Tg. 8) Heat resistance after boiling After boiling for 3 hours, it was immersed in solder at 260 ° C for 30 seconds to check for abnormalities.

[0041]

According to the present invention, a polybenzazole fiber cloth is used as a base material, a thermosetting resin composition, preferably a polyfunctional cyanate composition is used, and an insulating inorganic filler is compounded. The printed wiring board using this copper-clad laminate is excellent in reliability such as heat resistance after absorption of moisture, electrical insulation and migration resistance, and heat resistance. And a low coefficient of thermal expansion.
Also, in drilling, laser, preferably on the copper foil surface,
Melting point above 900 ℃ and binding energy 300kcal / mol
An organic substance containing one or more of the above metal compound powders, carbon powders, and metal powders is arranged, and directly irradiated with a high-energy carbon dioxide laser to process a copper foil, and to form through holes and / or vias. By forming the holes, a method for manufacturing a printed wiring board which is excellent in workability, economy, and the like and excellent in connection reliability of the holes is provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) // B23K 101: 42 (72) Inventor Mitsuru Nozaki 6-1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo factory F term (reference) 4E068 AF01 AJ01 CA02 CA03 DA11 DB01 DB14

Claims (5)

[Claims] 1. A metal compound powder having a melting point of at least 900 ° C. and a binding energy of at least 300 kJ / mol on a copper foil of a thermosetting resin copper-clad laminate using a polybenzazole fiber cloth as a base material. One or two or more of powder and metal powder 3-9
A method for producing a printed wiring board, comprising arranging a composition composed of an organic substance containing 7 vol% or performing metal oxide treatment or chemical treatment, and directly irradiating a carbon dioxide gas laser to form holes. 2. The energy of a carbon dioxide laser is 20-60.
The method for manufacturing a printed wiring board according to claim 1, wherein energy selected from mJ / pulse is used. 3. A printed wiring board using a copper-clad board obtained by dissolving and removing copper foil burrs generated around a hole by a chemical solution after forming a hole and partially dissolving and removing a surface copper foil in a thickness direction. Manufacturing method. 4. The method for producing a printed wiring board according to claim 1, wherein the thermosetting resin is a composition in which an insulating inorganic filler is mixed in the thermosetting resin in an amount of 10 to 80% by weight. . 5. The thermosetting resin is a resin composition containing a polyfunctional cyanate ester and a polyfunctional cyanate ester prepolymer as essential components. 5. The method for manufacturing a printed wiring board according to 4.