JP2001199006A - Double-side treated copper foil with protective film and printed wiring board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copper foil for manufacturing a high density printed wiring board excellent in reliability by boring small diameter holes in a copper clad sheet free from a dent and having no resin bonded thereto. SOLUTION: High output carbon dioxide laser is directly applied to a double- side treated copper foil with a protective sheet wherein a protective sheet (a) is arranged to the surface to which nickel treatment or nickel alloying treatment is applied of a double side treated copper foil (b) wherein nickel treatment (c) or nickel alloying treatment (d) is applied to at least a single surface to be at least partially bonded, a copper clad laminated sheet formed using the treated copper foil and the copper foil subjected to nickel or nickel alloying treatment of a copper clad sheet to form through-holes and/or blind viaholes to obtain a printed wiring board. By this constitution, a double-side treated copper foil which has no dent and in which through-holes and/or viaholes can be bored by the direct irradiation of carbon dioxide laser can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a double-sided copper foil having at least one surface treated with nickel or a nickel alloy,
A protective sheet is disposed on at least a surface treated with nickel or a nickel alloy, and a double-sided treated copper foil with a protective sheet integrated by bonding at least a part of the protective sheet to a copper foil, and a printed wiring board using the copper foil About. More specifically, the present invention relates to a copper clad board formed by laminating and molding using a double-sided treated copper foil to which a protective sheet is adhered and having no surface dents or resin adhesion, and a printed wiring board using the copper clad board.

[0002]

2. Description of the Related Art Conventionally, in a high-density printed wiring board used for a semiconductor plastic package or the like, a surface-treated copper foil that has been subjected to a surface treatment has not been used. Further, since a general copper foil does not have a carrier, that is, a protective sheet, dents and resin residue were observed on the surface of the copper foil when laminated and formed. When a fine pattern is formed by using these, pattern breakage, short circuit, etc. occur due to resin dents on the surface, resin adhesion, and the like, resulting in a high defect rate. Further, in drilling, the through-hole was drilled with a mechanical drill. In recent years, drills have become smaller and smaller in diameter.
When drilling such small diameter holes, the drill diameter is small, so there are drawbacks such as bending, breaking, slow processing speed, etc. when drilling, productivity, reliability, etc. Was a problem.

[0003] The blind via hole has been formed by etching a copper foil at a position to be drilled in advance and then using a low energy carbon dioxide laser. This process has drawbacks such as the time required for the etching process. In addition, a hole of the same size was made in advance by using a negative film on the front and back copper foils in a predetermined manner using a negative film. When trying to form a hole that penetrates the front and back with a carbon dioxide gas laser, there are gaps in the position of the inner copper foil, a gap between the upper and lower holes and the land, poor connection, and the inability to form the front and back lands was there. Furthermore, heat resistance, migration resistance, electrical insulation after moisture absorption, and the like have become problems in printed wiring boards that have become increasingly dense in recent years.

[0004]

SUMMARY OF THE INVENTION The present invention provides a double-sided treated copper foil, a copper-clad board using the treated copper foil and a printed wiring board using the copper-clad board, which contribute to solving the above problems. With the goal.

[0005]

SUMMARY OF THE INVENTION The present invention provides a double-sided copper foil for preparing a copper-clad plate, in which at least one side of the copper foil which has been treated with nickel or a nickel alloy, has a portion thereof treated with nickel or a nickel alloy. Preferably, the present invention provides a double-sided treated copper foil with a protective sheet having a part of its periphery adhered to the protective sheet. Further, the present invention provides a printed wiring board using a double-sided copper foil as at least an outer layer, laminating and forming a copper-clad board having the double-sided copper foil adhered to the outer layer, and using the copper-clad board. ADVANTAGE OF THE INVENTION According to this invention, by providing a protective sheet, the copper clad board with few dents on a copper foil and little resin adhesion is provided. Furthermore, by using it to form a printed wiring board, there is no short circuit, disconnection, or the like in a fine pattern due to dents, resin adhesion, and the like, and a high-density printed wiring board is provided.

According to the present invention, furthermore, in drilling a hole when a printed wiring board is formed, a carbon dioxide laser is directly irradiated onto a copper foil surface treated with nickel or a nickel alloy, thereby forming a through hole and / or a blind via. A hole can be formed, so that time such as etching and removing the copper foil in advance can be saved, and a small-diameter hole can be efficiently created at high speed.

According to the present invention, further, a copper foil burr generated in the hole after the hole is formed by the carbon dioxide gas laser is sprayed or sucked with a chemical solution to partially remove the surface copper foil in the thickness direction by etching. Provided is a printed wiring board formed by etching and removing copper burrs on inner and outer layers. The copper foil burr on the surface layer can be removed by mechanical polishing, but etching with a chemical is preferred from the viewpoint of dimensional change and the like.

Further, according to the present invention, it is preferable to use a polyfunctional cyanate ester and a thermosetting resin composition containing the cyanate ester prepolymer as an essential component as an insulating layer of a copper clad board. And a printed wiring board having excellent migration resistance and the like.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A printed wiring board is obtained by forming a circuit on both sides using a double-sided copper-clad board obtained by plating a copper-clad board which has been drilled and etched with a chemical solution by copper plating. Can be In order to make the circuits on the front and back fine, it is preferable that the copper foil on the front and back layers be 2 to 7 μm. In this case, there is no occurrence of defects such as short circuits and cut patterns, and high-density printed wiring boards are created can do. Of course, a printed wiring board can be made of a single-sided copper-clad board, but in this case, copper plating is not performed.

[0010] The present invention relates to a copper-clad board or a multilayer board obtained by using a double-sided treated copper foil for at least the outer layer copper foil,
A copper-clad board or a multilayer board is formed by laminating a copper foil having at least one surface subjected to nickel treatment or nickel alloy treatment, preferably a part of the periphery of which is adhered to a protective sheet, and a B-stage sheet. After that, peel off the protective sheet,
After leaving it as it is and irradiating it with a carbon dioxide gas laser to form through holes and / or blind via holes, the protective sheet is peeled off to obtain a printed wiring board. In the present invention, the protective sheet means a plastic film or a composite film made of metal and resin that can be peeled off after lamination molding. The copper-clad board obtained in this way is a dent on the copper foil surface,
There is almost no resin adhesion, and the occurrence of shorts and disconnections due to dents, resin adhesion, etc. can be suppressed in the subsequent fine pattern formation, and the occurrence of defective rates can be reduced in the production of high-density printed wiring boards.

In the case of drilling holes in the copper clad board, a protective sheet is adhered. After peeling off the protective sheet, drilling is performed from above by drilling with a mechanical drill. For holes with a diameter of 80-180 μm, which are difficult to drill by mechanical drilling, peel off the protective sheet or irradiate the energy directly on the copper foil with pulse oscillation using a carbon dioxide laser with the protective sheet attached, Drill through holes and / or blind via holes. In the case where the protective sheet is a plastic film, it is preferable to perform perforation with a carbon dioxide gas laser with the plastic film attached. Holes smaller than 80 μm are drilled with an excimer laser or a YAG laser. A printed wiring board formed by drilling is mainly used for mounting a semiconductor chip. The processing speed is much faster than with a drill, the productivity is good, and the economy is excellent. After drilling, burrs are generated on the front and back surfaces and the inner layer copper foil. In this case, an etching solution is sprayed at a high pressure or sucked through the holes to dissolve and remove burrs on the inner and outer layer copper foils. After that, the whole is copper-plated by a standard method, and a circuit is formed to form a printed wiring board.

The double-sided copper foil required for producing the copper-clad board used in the present invention is a copper foil having at least one surface subjected to nickel treatment or nickel alloy treatment. This copper foil is arranged on the protective sheet side such that the surface subjected to the nickel treatment or the nickel alloy treatment faces the outer layer side of the copper clad board, and at least a part thereof is used by being adhered to the protective sheet. A double-sided copper foil may be placed on a prepreg and a protective film may be placed outside the prepreg, but dust and the like are likely to be mixed in during setup. Therefore, in the present invention, at least a part of the protective sheet is set up by bonding it to a copper foil. The surface of the copper-clad plate that adheres to the resin, which is opposite to the surface that has been subjected to the nickel treatment or the nickel alloy treatment, has been subjected to a generally known surface treatment. Of course, nickel treatment and nickel alloy treatment are also included. The copper foil surface on the resin side has irregularities of several μm. The surface of the protective sheet of the double-sided copper foil on which the nickel treatment or the nickel alloy treatment has been performed may or may not have irregularities. As the thickness of the copper foil of the double-sided treated copper foil, one obtained by treating both sides of an electrolytic copper foil having a thickness of 3 to 12 μm is preferably used. 9 to 1 thickness for inner layer
8 μm is preferably used. The protective sheet to which the copper foil is adhered is not particularly limited, but a protective sheet that adheres to the copper foil during lamination and becomes difficult to peel off is not used.

The copper clad board used in the present invention has at least one
It is a copper-clad board or a multilayer board having more than one copper layer, and may be a board-reinforced board, a film board, or a resin alone without a reinforcing board. However, from the viewpoint of dimensional shrinkage and the like, a glass cloth-based copper-clad plate is preferred. or,
When creating a high-density circuit, a thin copper foil can be used as the surface layer from the beginning, but preferably, a thick copper foil of 9 to 12 μm is laminated and formed, and a hole is formed by a carbon dioxide gas laser or the like. After processing, the surface copper foil is 2 ~ 7μm with etchant,
It is preferable to use one thinned to 3 to 5 μm. The double-sided treated copper foil with a protective sheet of the present invention is placed outside the prepreg at the time of lamination molding, and is laminated and molded under heat, pressure, preferably under vacuum using a stainless steel plate outside the prepreg. After lamination molding, depending on the processing method, the protective sheet is peeled and perforated.

As the base material of the copper clad board, generally known organic and inorganic woven fabrics and nonwoven fabrics can be used. Specifically, examples of the inorganic fibers include fibers such as E, S, D, and M glass, and ceramic fibers. Also, as organic fiber,
Examples thereof include wholly aromatic polyamide, liquid crystal polyester, and polybenzazole fibers. These may be mixed.
Films such as a polyimide film can also be used.

As the resin of the thermosetting resin composition of the copper clad board used in the present invention, generally known thermosetting resins are used. Specifically, an epoxy resin, a polyfunctional cyanate ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, an unsaturated group-containing polyphenylene ether resin, and the like, and one or more kinds Are used in combination. From the point of the through-hole shape in processing by carbon dioxide laser irradiation, a thermosetting resin composition having a glass transition temperature of 150 ° C. or higher is preferable, and in terms of heat resistance, migration resistance, electrical characteristics after moisture absorption, and the like. Multifunctional cyanate resin compositions are preferred.

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 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-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 and inorganic 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 copper-clad board used in the present invention can contain an insulating inorganic filler in the thermosetting resin composition. Particularly, for carbon dioxide gas laser drilling, 10 to 80% by weight, preferably 20 to 70% by weight is added to make the shape of the hole uniform. The kind of the insulating inorganic filler is not particularly limited. Specific examples include talc, calcined talc, aluminum hydroxide, magnesium hydroxide, kaolin, alumina, wollastonite, synthetic mica, and the like, and one or more kinds are used in combination.

The thermosetting resin composition itself is cured by heating, but when the curing speed is slow and the workability, economy and the like 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 parts by weight, per 100 parts by weight of the thermosetting resin.

The copper foil used in the present invention is a copper foil treated on both sides. The surface of the copper foil on the protective sheet side is subjected to a nickel treatment or a nickel alloy treatment. As the treatment on the copper foil side to be bonded to the resin of the copper-clad laminate on the opposite side, a generally known treatment for a copper-clad laminate is used. This treatment may of course be a nickel treatment or a nickel alloy treatment. As the nickel alloy treatment, a known alloy treatment can be used. For example, alloy treatment of an alloy of nickel and chromium, nickel-chromium-iron, and the like can be given. Although the thickness of the treatment is not particularly limited, it is generally 1 to 5 μm.

There is no particular limitation on the protective sheet to which this double-sided copper foil is to be attached, but the thickness is preferably
20-200 μm thermoplastic films are used. There is no particular limitation on the type of film, and a film that adheres to a copper foil during lamination and becomes difficult to peel off is not used. Specifically, a known heat-resistant film such as a polyester film, a Teflon film, a tri-vinegar film, and a 4-methylpentene-2 film can be used. Also, a composite film in which a resin is adhered to one surface of a metal foil can be used. This film has a role of preventing dents in copper foil treatment and resin adhesion when laminated and formed, and a stainless steel plate placed outside thereof is heated and pressed, preferably a copper-clad plate laminated and formed under vacuum. Then, mechanical drilling and carbon dioxide laser drilling are performed after the film is peeled or left as it is. At least a part of the protective film and the double-sided treated copper foil, preferably an end part, are used by bonding. The bonding method is
Generally known methods can be used. For example, a method of bonding with an adhesive, a method of bonding by heating and melting, and the like are used.

When a through hole and / or a blind via hole is made by a carbon dioxide gas laser, the protective film on the surface is peeled off, or directly on the copper foil of the copper-clad plate treated with nickel or nickel alloy after leaving it as it is. Drill holes by irradiating a carbon dioxide laser beam. From the point of prevention of copper foil contamination attached to copper and organic matter that is scattered when drilling, copper foil contamination is prevented by performing drilling while leaving the film on the surface as it is, the scattered residue falls on the film. Effective for prevention. The wavelength of CO2 laser is 9.3 ~ 1
0.6 μm is used. Energy is 80-180μm
When drilling holes, preferably 10 to 60 mJ / pulse,
A predetermined pulse is irradiated to make a hole. In the case of drilling through holes and / or blind via holes, any of a method of irradiating holes with the same energy from the beginning to the end and a method of increasing or decreasing the energy in the middle of the holes may be used.

In drilling holes with the carbon dioxide laser of the present invention, burrs of the copper foil are generated around the holes. The method of etching and removing copper burrs generated in the holes is not particularly limited. For example, Japanese Patent Application Laid-Open Nos. 02-22887, 02-22896, and 02
-25089, 02-25090, 02-59337, 02-60189, 02-1
66789, 03-25995, 03-60183, 03-94491, 04-19
9592 and 04-263488, and 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. When the inner layer copper burrs are removed by etching, a part of the surface of the copper foil is also removed by etching at the same time to have a thickness of 2 to 7 μm.
By setting the thickness to m, preferably 3 to 5 μm, a fine pattern can be formed on the subsequent copper-plated copper foil, and a high-density printed wiring board can be obtained.

On the back surface of the copper-clad plate, it is possible to simply arrange a metal plate in order to prevent the laser machine table from being damaged by the laser during penetration.
A resin layer to which at least a part of the surface of the metal plate is adhered is adhered to the copper foil on the back surface of the copper clad plate, and the metal plate is peeled off after drilling through holes.

In most cases, a resin layer of about 1 μm is left on the surface of the copper foil surface on the surface of the surface inside the hole where the resin of the inner copper foil is adhered. This resin layer can be removed in advance by a generally known treatment such as desmear treatment before etching. However, if the liquid does not reach the inside of the small-diameter hole, the removal of the resin layer remaining on the surface of the copper foil of the inner layer remains. May occur, resulting in poor connection with copper plating. Therefore, more preferably, first, the inside of the hole is treated in the gas phase to completely remove the residual layer of the resin,
Next, copper burrs inside the hole and on the front and back are removed by etching. 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 a reactive gas,
Oxygen is mainly used to chemically treat the surface. 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.

The inside of the hole can be subjected to ordinary copper plating.
80% by volume or more can be filled. In drilling, an excimer laser, a YAG laser or the like can be used. Further, the combined use of the lasers is also possible.

[0030]

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

Example 1 900 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
2,000 parts of an inorganic filler (trade name: calcined talc, Nippon Talc Co., Ltd., average particle size 4 μm), and 8 parts of black pigment, and uniformly stirred and mixed to prepare Varnish A. Obtained. This varnish A is impregnated with a glass woven cloth having a thickness of 100 μm and
It dried at ° C, and prepared the prepreg (prepreg B) whose gel time (at 170 ° C) was 102 seconds and the content of the glass cloth was 50% by weight.

Nickel alloy treatment (Japan Energy Co., Ltd. Y treatment, LD
4μm thick electrolytic copper foil, 50μ thick
Copper foil C with protective film (Fig. 1) with 4 ends of 530mm square attached to one side with an adhesive on a 4-methylpentene-1 film (trade name: TPX, manufactured by Mitsui Chemicals, Inc.) Created. Four prepregs B are arranged, and copper foil C with a protective film is used on the upper and lower outer sides, the copper foil side is arranged so as to face the prepreg side, and a 1.5 mm thick stainless steel plate is arranged on the outer side, 1
Put between 5 hot plates (Fig. 2), 200 ℃, 20kgf / cm ² , 30mmHg
Laminate molding was performed for 2 hours under the following vacuum to obtain a double-sided copper-clad laminate D. On the other hand, a resin obtained by dissolving polyvinyl alcohol in water was applied to one surface of an aluminum foil having a thickness of 50 μm.
After drying for a minute, a backup sheet E having a coating film having a thickness of 20 μm was prepared.

The protective film on the lower side of the laminated copper-clad plate with a protective film is peeled off, and a backup sheet E is placed on the outside thereof (FIG. 3 (1)). Three hundred holes were directly irradiated with 900 carbon dioxide lasers in a 50 mm square with pulse output of 15 mJ and three shots of 20 mJ, and a total of 70 blocks of through holes were drilled (FIG. 3 (2)). After removing the upper protective film and the lower backup sheet E and placing them in a plasma device for processing, the SUEP solution is sprayed at a high speed to dissolve and remove the burrs on the front and back, and simultaneously remove the copper foil on the front and back surfaces. It dissolved to a residual thickness of 4 μm (FIG. 3 (3)). After desmearing, copper plating is applied to a thickness of 15 μm (Fig. 3 (4)), a circuit (line / space = 50/50 μm), solder ball pads, etc. are formed by an existing method, and at least a semiconductor chip mounting portion and bonding Except for the pad portion and the solder ball pad portion, they were covered with a plating resist, plated with nickel and gold, and a printed wiring board was prepared. Table 1 shows the evaluation results of the printed wiring board.

Example 2 Epoxy resin (trade name: Epikote 1001, Yuka Shell Epoxy Co., Ltd.) 300 parts, and epoxy resin (trade name: ESC
N220F, manufactured by Sumitomo Chemical Co., Ltd.) 700 parts, dicyandiamide
35 parts, 1 part of 2-ethyl-4-methylimidazole was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide,
Varnish F was obtained by uniformly stirring and mixing. This is 100μm thick
Impregnated in glass woven cloth, dried, gelled for 150 seconds, prepreg G with a glass cloth content of 48% by weight, impregnated in 50 μm thick glass cloth, dried and gelled for 170 seconds, glass cloth Prepreg H having a content of 31% by weight was prepared.

Using one piece of this prepreg G, place a 12 μm electrolytic copper foil on the top and bottom of the prepreg, at 190 ° C., 20 kgf / cm ² , 3
Lamination molding was performed at 0 mmHg to obtain a double-sided copper-clad laminate I. After forming a circuit on the front and back of this plate, performing black copper oxide treatment, placing one of the above prepregs H on each of the upper and lower sides, and outside thereof, 12 μm electrolytic copper foil subjected to nickel treatment on the shiny surface by 3 μm, The nickel-treated surface was placed so as to face the side of a Teflon film having a thickness of 20 μm, copper foils with a protective film having a width of 5 mm adhered on both sides thereof were laminated, and laminated and formed in the same manner to form a four-layer multilayer board. After that, leaving the protective film on the upper surface as it is, peeling off the lower protective film, placing the backup sheet E on the lower side, irradiating 2 shots at 15 mJ of carbon dioxide laser output and 2 shots at 20 mJ from the top of the protective film Through holes.

Further, the plate was used, and three shots were irradiated from above the plate at an output of 15 mJ of a carbon dioxide laser to form a blind via hole. The whole was subjected to SUEP treatment to dissolve and remove the copper foil to a residual thickness of 3 μm, and then subjected to desmear treatment with an aqueous solution of potassium permanganate. Subsequently, copper plating and the like were performed in the same manner as in Example 1 to obtain a printed wiring board. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 A copper clad board of Example 1 was prepared using a general electrolytic copper foil having a thickness of 12 μm. But there was no hole.

Comparative Example 2 In Example 2, a four-layer plate was prepared using a general electrolytic copper foil having a thickness of 12 μm as a surface layer, black magic was applied to the surface, and holes were similarly formed by a carbon dioxide gas laser. However, there was no hole.

Comparative Example 3 In Example 2, an epoxy resin (trade name: Epicoat)
5045) 2,000 parts, dicyandiamide 70 parts, and 2-ethylimidazole 2 parts were dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and 800 parts of the insulating inorganic filler of Example 1 was further added. I got a varnish. This is impregnated and dried in a 100 μm thick glass woven fabric, and a prepreg J with a gel time of 140 seconds (at 170 ° C.), a glass content of 52% by weight, a gel time of 180 seconds and a glass cloth of 50 μm thickness are used. A prepreg K having a ground glass content of 35% by weight was obtained. Stack two sheets of this prepreg J, 12μm on both sides
Was placed in a vacuum at 180 ° C., 20 kgf / cm ² , and 30 mmHg or less for 2 hours to obtain a double-sided copper-clad laminate L. Circuits were formed on both sides of the laminate L, and after treatment with black copper oxide, one prepreg L was placed on each side, and a 12 μm copper foil was placed outside the prepreg L. Lamination was performed in the same manner as in Example 2. Using this, a through hole having a hole diameter of 15 μm was formed by a mechanical drill. No holes were made even when irradiated directly with a carbon dioxide laser. Copper plating was performed without performing the SUEP treatment, and a printed wiring board was similarly formed. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 4 In Example 2, the upper and lower copper foils were removed by etching using a double-sided copper-clad board I (FIG. 4 (1)) so that the through holes in the inner layer had a hole diameter of 100 μm. After forming a circuit and treating the copper foil surface with black copper oxide, prepreg
H was placed thereon, and a 12 μm electrolytic copper foil was disposed outside thereof, and laminated and formed in the same manner to form a four-layer plate. Using this multilayer board, 900 holes with a hole diameter of 100 μm at the position of the surface where the through hole is formed,
The copper foil was opened by etching. Similarly, 900 holes having a hole diameter of 100 μm were formed at the same position on the back surface (FIG. 4B). A total of 63,000 holes, 70 blocks of 900 patterns per pattern, were shot from the surface with a carbon dioxide laser at an output of 15 mJ for 4 shots.
A through hole for a through hole was formed (FIG. 4 (3)). Thereafter, in the same manner as in Comparative Example 3, a desmear treatment is performed once without performing the SUEP treatment, and a copper plating is performed by 15 μm (FIG. 4 (4)).
Circuits were formed on the front and back sides, and a printed wiring board was similarly prepared. Table 1 shows the evaluation results.

Table 1 Item Practical example Comparative example 1 2 3 4 Gap between front and back land copper foil (μm) 0 0 0 22 Displacement (μm) between inner layer and hole wall − 0 0 36 Pattern cut And short (pcs) 0/200 0/200 55/200 52/200 Glass transition temperature (° C) 235 160 139 160 Through-hole heat cycle test (%) 100 cycles 1.1 1.2 1.6 3.9 300 cycles 1.2 1.4 3.8 6.5 500 cycle 1.4 1.6 4.8 29.9 drilling time (min) 19 14 630 - migration resistance (HAST) (Omega) normal ^{3x10 11 - 1x10 11 -. 200hrs} 8x10 8 <10 8 500hrs 7x10 8 -.. 700hrs 6x10 8 1000hrs. 5x10 ⁸

<Measurement method> 1) Clearance between front and back hole positions A hole with a hole diameter of 100 or 150 μm (mechanical drill)
70 blocks (63,000 holes total) were prepared as 00 holes / block. The time required to drill 63,000 holes in a single copper-clad plate by drilling holes with a carbon dioxide laser and a mechanical drill, the gap between the copper foil for front and back lands and the hole, and the gap between the inner layer copper foil and the hole wall Showed the maximum value. 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 250 μm for 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 500 cycles The maximum value of the rate of change of the resistance value was shown. 5) Migration resistance (HAST) A total of 50 copper-plated through-holes with a hole diameter of 100 μm or 150 μm (mechanical drilling) are alternately connected, one on each side, a total of 50 holes. Make a total of 100 sets, 130 ℃, 85% R
After processing at H, 1.8 VDC for a predetermined time, the samples were taken out and the insulation resistance between through holes arranged in parallel was measured.

[0043]

According to the present invention, a protective sheet is disposed on a nickel-treated or nickel-alloy-treated surface of a double-sided copper foil having at least one surface treated with a nickel or nickel alloy, and a carrier having at least a part thereof adhered thereto is provided. A copper-clad laminate obtained by laminating and forming a plurality of sheets using copper foil has a very small number of dents and resin adhesion. In the subsequent pattern formation, there is no short circuit or pattern breakage resulting in a high-density printed wiring board. be able to. In addition, hole diameter 8
In the case of forming a through hole and / or a blind via hole of 0 to 180 μm, mechanical drilling is performed by directly irradiating a carbon dioxide gas laser energy on the copper foil of the obtained copper clad board or the protective sheet to perform drilling. The processing speed is much faster than that of
Further, thereafter, by dissolving and removing the copper foil burrs generated in the holes, at the same time, dissolving a part of the surface of the copper foil, the remaining thickness of the copper foil to 2 to 7 μm, preferably 3 to 5 μm, A fine pattern can be formed even in the plating-up by copper plating, and a high-density printed wiring board can be produced. In addition, by adding an insulating inorganic filler, the pore shape becomes good, and one having excellent hole connection reliability is obtained.In addition, a polyfunctional cyanate compound as a thermosetting resin composition, A printed wiring board obtained by using a resin composition containing a cyanate ester prepolymer as an essential component has excellent heat resistance, migration resistance, and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a double-sided treated copper foil with a protective sheet.

FIG. 2 is an explanatory diagram showing a configuration at the time of lamination molding.

[FIG. 3] A backup sheet is arranged below the laminated copper clad board of Example 1 (1), a through hole is formed by a carbon dioxide laser (2), burrs are removed by SUEP, and etching of a surface copper foil is performed ( 3) is a process drawing of copper plating (4).

FIG. 4 is a process diagram of drilling and copper plating of a double-sided copper-clad multilayer board of Comparative Example 4 with a carbon dioxide gas laser (without SUEP).

[Explanation of symbols]

A Protective film with one part of double-sided treated copper foil adhered to one side a Protective film b Copper foil b1 Nickel alloy treated copper foil on shiny side c Nickel treatment on copper foil surface that can be drilled with carbon dioxide laser Or nickel alloy treatment d General surface treatment of copper foil e Glass cloth substrate laminate f Polyvinyl alcohol layer g Aluminum foil for backup sheet h Burr of generated outer layer copper foil i Through hole drilled with carbon dioxide laser j Etching Outer layer copper foil thinned by thinning k Through hole plated through hole l Portion etched for through hole m Double-sided copper-clad laminate n Surface land copper foil o Inner layer pattern copper foil p Hole with CO2 laser Drilled through hole with poor shape q Inner layer copper foil with misalignment r Through hole with copper-plated defective shape s 4 prepreg B t stainless steel Less board

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AB16A AB17A AB31A AB33A AK01C AK08B AK08C AK31B AT00B AT00C BA02 BA03 BA06 BA10A BA10B BA10C BA13 BA32B BA32C CA23B EJ64A GB43 JB13B JJ03 JL00 JL01 J02

Claims (5)

[Claims] 1. A double-sided treated copper foil for producing a copper-clad board, wherein at least one side of the double-sided treated copper foil treated with nickel or its alloy is separated from the copper foil after lamination molding on at least the surface treated with nickel or its alloy. A double-sided treated copper foil with a protective sheet, wherein a protective sheet to be applied is disposed, and at least a part of the protective sheet is adhered to the copper foil. 2. A copper foil with a protective sheet is placed on at least one side of a B-stage sheet, and laminated and formed under heat and pressure to form a copper-clad board having a double-sided copper foil adhered to an outer layer. Using sufficient CO2 laser energy to process the copper foil on the board, the protective sheet of the copper clad board is adhered or peeled off, and then the CO2 laser is directly irradiated from the copper foil side to make the through hole And / or a printed wiring board formed by forming a blind via hole. 3. After the hole is formed by the carbon dioxide gas laser according to claim 2, the copper foil burr generated around the hole is dissolved and removed with a chemical solution, and at the same time, the surface copper foil is partially dissolved and removed in the thickness direction. A printed wiring board, characterized in that: 4. The thermosetting resin used for the copper clad board is a thermosetting resin composition containing a polyfunctional cyanate ester compound and the cyanate ester prepolymer as essential components. The printed wiring board according to claim 2. 5. The thermosetting resin composition, wherein an insulating inorganic filler is blended in an amount of 10 to 80% by weight.
Or the printed wiring board according to 4.