JP2001156461A - Build-up multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board wherein the base material of printed wiring board for build-up is improved for forming a high density circuit. SOLUTION: An inner layer and a build-up layer comprises a thermosetting resin composition layer of a nonwoven glass fiber whose thickness is 100 μm or less and which includes flat glass fibers by 90 wt.% or more that is rectangular in cross section, with its major diameter/minor diameter of 3.1/1-5/1, whose cross-section area is 90-98% of a rectangle circumscribing the cross section of glass fiber, with reduced fiber diameter 5-17 μm. Thus, a multilayer printed wiring board is provided which is excellent in surface smoothness and boring characteristics with a carbon dioxide laser as well as in connection reliability for the hole while suitable for forming a high density circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a build-up multilayer printed wiring board using a novel glass nonwoven fabric. More specifically, the present invention relates to a high-density printed wiring board having a small-diameter hole and capable of forming a fine circuit on the surface. This high-density printed wiring board is mainly used for small and new semiconductor plastic packages and the like.

[0002]

2. Description of the Related Art Hitherto, a high-density glass cloth base multilayer printed wiring board used for a semiconductor plastic package or the like has used a glass woven cloth. This glass woven fabric multilayer printed wiring board has large irregularities in the hole wall due to the difference in the difficulty of drilling between the glass woven fabric and the resin layer when a small diameter hole is pierced with a carbon dioxide gas laser. In addition, there is a problem in terms of performance, and the surface irregularities make it difficult to form a fine circuit. Conventionally, a through hole for a through hole is drilled. In recent years, the diameter of drills has become increasingly smaller, and the hole diameter has become 150 μm or less.When drilling such small diameter holes, the drill diameter is small, so the drill bends, breaks, and the processing speed is slow when drilling. However, there are problems such as productivity and hole connection reliability. 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 is a defect such as displacement of the inner layer copper foil, displacement of the upper and lower holes, poor connection, and the inability to form a land on the front and back. .

[0003]

SUMMARY OF THE INVENTION The present invention significantly improves the above-mentioned disadvantages by using a glass fiber non-woven fabric which has not been conventionally used as a build-up material, in particular, a glass non-woven fabric having a flat fiber cross section. It is another object of the present invention to provide a build-up multilayer printed wiring board having a novel configuration.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a glass fiber having a flat cross-section, a flattening ratio expressed by a long diameter / short diameter of the cross-section of 3.1 / 1 to 5/1, and a cross-sectional area of the glass fiber. 90 to 98% of the area of the rectangle circumscribed to the glass fiber cross-section, the converted fiber diameter is 5 ~ 17μm flat glass fiber is 90% by weight or more of the thermosetting resin composition layer of the glass fiber nonwoven fabric substrate, Provided is a build-up multilayer printed wiring board used for an inner layer and a build-up layer. ADVANTAGE OF THE INVENTION According to this invention, the hole shape of the through-hole and brand via hole drilled by the carbon dioxide gas laser etc. is favorable, is uniform, and the printed wiring board excellent in hole connection reliability is provided. In addition, the printed wiring board of the present invention is excellent in surface smoothness and warpage by using the above-described glass fiber nonwoven fabric. Furthermore, the homogeneity of the perforated hole wall can be further improved by adding 10 to 80% by weight of the insulating inorganic filler to the thermosetting resin.

[0005] Drilling is preferably performed using a carbon dioxide gas laser. In this case, the copper foil at the location where the hole is to be drilled is removed in advance, and low-energy carbon dioxide laser energy is applied to form the blind via hole. It is also possible to form. However, preferably, an auxiliary layer for drilling is formed on the copper foil of the copper-clad multilayer board, and a carbon dioxide gas laser having sufficient energy for processing the copper foil is directly irradiated from above to form a through hole and / or A blind via hole is formed, and a high-density printed wiring board is created using the blind via hole. This drilling method is excellent in workability, automatically compensates for dimensional shrinkage of the inner layer, the processing speed is much faster than mechanical drilling, and the connection reliability of the obtained small diameter hole is also excellent. This is a significant improvement over the conventional drilling method.
In order to form a circuit having a higher density, the copper burrs generated around the holes are dissolved and removed, and at the same time, the copper foil on both sides is partially dissolved and removed in the thickness direction. As a result, the thickness of the copper foil after copper plating can be kept thin, and a high-density printed wiring board can be produced.

The thermosetting resin used for the copper-clad multilayer board is preferably obtained by using a polyfunctional cyanate compound and a resin composition containing the cyanate ester prepolymer as an essential component. The obtained multilayer printed wiring board is excellent in heat resistance after moisture absorption, migration resistance, heat resistance, and the like.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a glass fiber having a flat cross section, and the flatness of the glass fiber is 3.times.
1/1 to 5/1, the cross-sectional area is 90 to 98% of the rectangular area circumscribing the glass fiber, and the converted fiber diameter is 5 to 17 μm
A build-up multilayer printed wiring board using, as an inner layer and a build-up layer, a layer obtained by adhering a thermosetting resin composition to a glass fiber nonwoven fabric substrate containing 90% by weight or more of flat glass fibers. In the present invention, the converted fiber diameter is a fiber diameter when the flat glass fiber cross-sectional area is converted into a circle. In the present invention, the flat glass fiber is a fiber having a flatness of 3.1 / 1 to 5/1, preferably 3.5 / 1 to 4.5 / 1. When the oblateness is less than 3.1 / 1, the effect of reducing the thickness of the nonwoven fabric and increasing the glass fiber content in the laminate is not sufficient because the short diameter is large. Flat glass fibers having an oblateness greater than 5/1 are difficult to produce, and the varnish resin impregnation speed is also slow, and impregnation is likely to occur. Further, the flat glass fiber used in the present invention has a cross-sectional area of 90 to 98% of a rectangular area circumscribing the cross section of the glass fiber. That is, the shape is almost rectangular. Paper making using this fiber, at this time, the binder content is 3 to 8% by weight
By doing so, the fibers are overlapped with the flat surface up and down, the thickness can be reduced, and a fiber having excellent surface smoothness when formed into a prepreg can be obtained. As the composition of the flat glass fibers used in the present invention, those which can produce flat glass fibers, such as E glass, T glass, and D glass, can be used. The glass fiber nonwoven fabric of the present invention is used as flat glass fiber alone or paper is made using glass fiber having a partially circular cross section. Flat glass fiber is used in an amount of 90% by weight or more.

The glass nonwoven fabric of the present invention is impregnated with a varnish made of a thermosetting resin composition and dried to prepare a B-stage prepreg, which is used for build-up. The resin content is not particularly limited, and it is sufficient that the space between the circuits of the inner layer plate is buried when laminated and the insulation with the copper foil thereover is sufficiently ensured. Generally, the amount of resin in the prepreg for build-up is
The content is 60 to 90% by weight in the thermosetting resin composition of the glass fiber nonwoven fabric base material. The prepreg for the inner layer plate generally has a resin amount of 50 to 70% by weight.

A generally known method for forming through holes and / or via holes is applied to a build-up printed wiring board prepared by using a prepreg comprising a special nonwoven fabric substrate of the present invention as an inner layer plate and a laminated material. it can. For example, drilling by a laser, drilling by a mechanical drill, and the like can be mentioned. If the hole diameter is 20 μm or more and less than 80 μm, an excimer laser or a YAG laser is used.
A carbon dioxide laser is preferably used when the diameter is not smaller than 150 μm, and a mechanical drill is preferably used when the diameter exceeds 180 μm. In particular, in the case of blind via drilling using a carbon dioxide gas laser, a conventional method of irradiating a low-energy carbon dioxide laser energy after etching the copper foil of the surface layer in advance can be used, but the dimensional accuracy of the baked film and the like can be used. This is a problem, and it is difficult to form a fine circuit. Therefore, preferably, the surface of the copper foil is subjected to metal oxide treatment or treatment with a chemical solution, or a metal compound having a melting point of 900 ° C. or more and a binding energy of 300 kJ / mol or more as an auxiliary layer on a multilayer copper-clad board. Powder, carbon powder or metal powder and an organic substance, preferably a paint mixed with a water-soluble resin composition, applied as a coating film, or on one side of a thermoplastic film, a resin having a total thickness of 30 to 200 μm. An auxiliary sheet for piercing obtained by adhering the composition is arranged, preferably laminated and adhered to a copper foil surface, and directly irradiated with a carbon dioxide laser from above the auxiliary layer to pierce the copper foil. Thereby, a through hole and / or a blind via hole can be formed.

After the holes are formed, burrs are generated on the front and back and inner layers of the copper foil. Therefore, an etching solution is sprayed to dissolve and remove the burrs of the copper foil generated on the holes. At the same time, when the copper foil is thick, the copper foil on the front and back sides is partially dissolved and removed in the thickness direction, so that the thickness is preferably 2 to 7 μm, more preferably 3 to 5 μm. When the copper foil is thin from the beginning, only the burrs are etched away while leaving the auxiliary layers formed on the front and back sides, and then the auxiliary layers are removed. Then, the entire board is copper-plated by a standard method, and a circuit is formed to form a printed wiring board.

The copper clad board used in the present invention has at least 3
A copper-clad multilayer board in which a copper foil layer of at least one layer is present, subjected to surface treatment as necessary, a flat glass fiber base thermosetting resin prepreg is arranged on at least one surface thereof, and a copper foil is placed on the outside thereof, Lamination molding is performed under heat, pressure and preferably under vacuum. Also, when creating a high-density circuit, use a thin copper foil from the beginning or laminate a thick copper foil from the beginning, and then etch the surface copper foil with an etchant for 2 to 2 hours.
Thickness down to 7 μm can be used. When a thin copper foil is used from the beginning, a copper foil with a carrier such as copper or aluminum is mainly used.

The carbon dioxide laser drilling auxiliary layer of the present invention is preferably used by bonding it to a copper clad multilayer board at the time of drilling. Generally, a resin composition containing one or more metal compound powders having a melting point of 900 ° C. or more and a binding energy of 300 kJ / mol or more, preferably a water-soluble resin composition, is applied and dried to form a coating film. Alternatively, the resin composition is applied to a thermoplastic film, dried, and used as a sheet. Laminate the auxiliary sheet on the copper-clad multilayer board with the resin adhering side facing the copper foil side under heat and pressure, or pre-wet the resin surface layer 3 μm or less with moisture and then add it at room temperature. By laminating the front and back sides under pressure, the adhesion to the copper foil surface becomes good, and a good hole shape can be obtained.

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 viewpoint of through-hole shape in processing by high-output carbon dioxide laser irradiation, a thermosetting resin composition having a glass transition temperature of 150 ° C or higher is preferable, and has moisture resistance, migration resistance, and electrical characteristics after moisture absorption. In view of the above, a polyfunctional cyanate resin composition is 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.

Other than 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.

As the copper-clad board used in the present invention, a thermosetting resin composition in which an insulating inorganic filler is suitably blended is used. Generally known ones can be used. Specifically, silicas such as natural silica, calcined silica and amorphous silica; white carbon, titanium white, aerosil, clay, talc, calcined talc, wollastonite, natural mica, synthetic mica, kaolin, magnesia, alumina, perlite , Aluminum hydroxide, magnesium hydroxide and other glass powders,
These are used alone or in combination of two or more. The compounding amount is 10 to 80% by weight in the total thermosetting resin composition.
%, Preferably 20-70% by weight. These are effective as a homogenizing agent for the resin composition layer on the pore wall when drilling with a carbon dioxide gas laser. The particle size is preferably 1 μm or less. The thermosetting resin composition of the present invention itself is cured by heating, but has a slow curing rate, and can use a known thermosetting catalyst for the used thermosetting resin because of poor workability and economic efficiency. . 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 auxiliary layer used in the present invention has a melting point of 900.
As the metal compound having a binding energy of 300 kJ / mol or more at a temperature of not less than ° C., generally known compounds can be used. Specifically, as the oxide, titanias such as titanium oxide,
Magnesia such as magnesium oxide, nickel oxide such as nickel oxide, manganese dioxide, zinc oxide such as zinc oxide, silicon dioxide, aluminum oxide, rare earth oxide,
Cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, and tungsten oxides such as tungsten oxide. Examples of the non-oxide include generally known ones such as boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, and rare earth oxysulfide. In addition, various glass powders which are a mixture of metal oxide powders can be used. Carbon powder and metal powder such as silver, copper, iron and nickel can also be used, and 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.

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, the hole wall adhesion and the like. 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 from 3 to 97 vol%, preferably from 5 to 95 vol%, and is mixed with the resin and uniformly dispersed.

The resin of the auxiliary layer is not particularly limited.
Generally known ones can be used, but if removed after drilling, they may adhere to the copper foil surface, and water-soluble resins are preferred. Specifically, a water-soluble polyester resin,
Polyether resin, polyvinyl alcohol, starch and the like are used. Also in this case, the various additives described above can be added.

The method of preparing the composition comprising the metal compound powder and the resin, and the method of forming a sheet are not particularly limited, but they are kneaded at a high temperature without a solvent using a kneader or the like, and extruded into a sheet on a thermoplastic film. The method of adhesion, the acidic resin is dissolved in a solvent, the above powder is added thereto, and the mixture is uniformly stirred and mixed. The mixture is used and applied as a paint to a copper foil surface and dried to form a coating film or a thermoplastic resin. A generally known method such as a method of applying a film on a film and drying to form a film can be used. The thickness is not particularly limited, but when applied, the thickness of the coating is preferably 30 to 100 μm, and when applied to a film to form a coating with a film, the total thickness including the film is preferably It should be 30-200 μm.

When laminating the copper foil surface under heating and pressure, the coated resin layer is directed to the copper foil surface, and the temperature is generally 40 to 150 ° C., preferably 60 to 120 ° C., and the linear pressure is generally
Lamination is performed under a pressure of 0.5 to 20 kg, preferably 1 to 10 kg, and the resin layer is melted and brought into close contact with the copper foil surface. The choice of lamination temperature depends on the melting point of the water-soluble resin used,
In general, lamination is performed at a temperature higher by 5 to 20 ° C. than the melting point of the resin, although it depends on the linear pressure and the laminating speed. The metal oxide treatment is not particularly limited, and examples thereof include black copper oxide treatment and MM treatment (MacDermid). Examples of the chemical treatment include generally known treatments such as CZ treatment (Mec).

The substrate-reinforced copper-clad board is first impregnated with a thermosetting resin composition and dried to form a B stage,
Create a prepreg. Next, a predetermined number of the prepregs are stacked, a copper foil is arranged on at least one side, and laminated under heat and pressure to form a copper-clad laminate. Further, a multi-layer board prepared by using this can also be used. The thickness of the outer layer copper foil is
Preferably, the thickness is 3 to 12 μm, and the thickness of the inner layer is 9 to 35 μm. The type of the copper foil is not particularly limited, but an electrolytic copper foil having a double-sided roughened foil can be used for the inner layer. Electrolytic copper foil is preferred for both the inner and outer layers.

Although there is no particular limitation on the method of etching and removing copper foil burrs generated in the holes, for example, Japanese Unexamined Patent Application Publication No.
02-22887, 02-22896, 02-25089, 02-25090, 02
-59337, 02-60189, 02-166789, 03-25995, 03-
60183, 03-94491, 04-199592, 04-263488, and a method for dissolving and removing metal surfaces with chemicals (SUEP
Called the law). The etching rate is generally from 0.02 to
Perform at 1.0 μm / sec. Further, in the case of removing the inner layer copper foil burr by etching, the spray angle and pressure of the etching solution are appropriately selected. A method of removing burrs by suction may also be used.

The energy of the carbon dioxide gas laser is preferably 20 to 60 mJ / pulse, and a high-output energy carbon dioxide laser beam is irradiated with necessary pulses (shots) by pulse oscillation and directly from above the auxiliary layer. Irradiate the copper foil to make holes. As the carbon dioxide laser, a wavelength of 9.3 to 10.6 μm in an infrared wavelength range is generally used. When drilling through holes and / or blind via holes, a method of irradiating energy selected from 20 to 60 mJ / pulse from the beginning to the end, a method of processing an insulating layer by increasing or decreasing the energy after processing a copper foil, etc. Processing can be performed by either method.

Although it is possible to simply arrange a metal plate on the back surface of the copper clad plate in order to prevent the laser machine table from being damaged by the laser when the holes penetrate, it is preferable to arrange a metal plate. A resin layer to which at least a part is adhered is adhered to a copper foil on the back surface of the copper-clad plate, and the through-hole is formed. When the front and back copper foils are thin, copper foil burrs generated around the holes are dissolved and removed with an etchant while leaving the front and back auxiliary layers after drilling. Also, if the copper foil on the front and back is thick,
Dissolve and remove the resin layer first after drilling through holes, then spray the entire surface with an etchant to partially dissolve and remove the copper foil on the front and back and remove the inner layer copper burrs and reduce the thickness of the surface copper foil. By setting the thickness to 3 to 7 μm, a fine circuit can be formed in the formation of a circuit plated up with copper thereafter.
High-density printed wiring boards can be produced. The latter is preferred from the viewpoint of removing surface dirt and foreign matter. The same applies to the case of forming a via hole.

In most cases, a resin layer having a thickness of 1 to 2 μm remains on the surface of the surface of the processed hole and the surface of the inner layer copper foil to which the resin is adhered. It is necessary to remove this resin layer by a generally known treatment such as a desmear treatment before etching. If the liquid does not reach the inside of the small-diameter hole, a residue of the resin layer remaining on the surface of the inner copper foil may be left behind, which may result in poor connection with copper plating. Therefore,
More preferably, the inside of the hole is first treated in a gas phase to completely remove the residual layer of the resin, and then the inside of the hole and the copper burrs on the front and back surfaces 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 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 to decompose and remove the resin layer.

A hole having a small diameter of 20 to 80 μm is formed by an excimer laser or a YAG laser. Although the wavelength is not particularly limited, a wavelength and energy capable of processing the copper foil are selected and used. The inside of the hole can be subjected to ordinary copper plating, but the inside of the hole can be partially filled with copper plating, preferably at least 80% by volume.

[0031]

The present invention will be specifically described below with reference to examples and comparative examples. Unless otherwise specified, parts and% represent parts by weight and% 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
Were added and dissolved and mixed. To this, 2,000 parts of an inorganic filler (trade name: calcined talc, average particle size 0.9 μm) and 8 parts of a black pigment were added, and uniformly stirred and mixed to obtain Varnish A. Also 62μ thick
m, the aspect ratio is 4/1, the area ratio is 92%, the converted fiber diameter is 10 μm,
Length dispersed high flat glass fiber of 13mm in polyethylene oxide dispersion solution, the epoxy silane coupling agent as an epoxy resin emulsion and a silane coupling agent in papermaking and nonwoven such basis weight is 20 g / m ² The used adhesive solution was prepared, adhered at 4% by weight, and dried at 150 ° C. to obtain a nonwoven fabric. Using this, the varnish A was impregnated and dried to prepare a prepreg B having a resin amount of 60% by weight and a gelling time of 101 seconds, a prepreg having a resin amount of 81% by weight and a gelling time of 86 seconds.
Created C.

Electrolytic copper foil having a thickness of 12 μm was placed above and below the four prepregs B and laminated and formed at 200 ° C., 20 kgf / cm ² and a vacuum of 30 mmHg or less for 2 hours to obtain a double-sided copper-clad laminate D. Was. An inner layer circuit is formed, the surface is subjected to CZ treatment (MEC Corporation), one prepreg C is placed on each side, 12 μm thick electrolytic copper foil is placed on the outside, and laminated under the same conditions as above It was molded to obtain a four-layer plate E. On the other hand, M
Mixed powder consisting of gO (54%) and SiO ₂ (46%) (average particle size: 0.
A varnish F was obtained by adding 800 parts of a 9 μm) water-soluble polyester resin to a varnish in which a water-methanol mixed solvent was dissolved, and uniformly stirring and mixing. This was applied to one side of a 50 μm thick polyethylene terephthalate so as to have a thickness of 20 μm and dried at 110 ° C. for 30 minutes to obtain a metal compound content of 40 vol%.
Was formed, and an auxiliary material G was obtained. On the back surface, the varnish F was applied to one surface of an aluminum foil having a thickness of 50 μm, and dried similarly to prepare a backup sheet H having a coating film having a thickness of 20 μm. The auxiliary material G is arranged on the front surface of the four-layer board E, the backup sheet H is arranged on the back side, and the resin layer is arranged so as to face the copper foil side. Laminated. From above, use a carbon dioxide laser machine to make a hole with a diameter of 100 μm within a 50 mm square.
900 direct carbon dioxide lasers with output 25mJ / pulse
1 shot, then 1 shot with output 10mJ / pulse
Finally, irradiate one shot at 30mJ / pulse, and the hole diameter is 100μ
m blind via holes were drilled. Also, 1 at 30 mJ / pulse
Shot, irradiation of 5 shots at 25mJ / pulse, 120μ pore size
m through holes were drilled.

After the auxiliary material layer of the front and back layers is peeled off and put into a plasma device for processing, a SUEP solution is sprayed at a high speed to dissolve and remove burrs on the front and back and the inner layer, and at the same time, the copper foil of the front layer is reduced to 4 μm. Dissolved. After desmearing, deposit copper plating 15μm, and then use the existing method (line / line).
Space = 50/50 μm). After forming a circuit on the front and back and performing CZ treatment, similarly, place one prepreg C each, place 12 μm electrolytic copper foil on the outside thereof, and laminate and mold under the same conditions as above to form a six-layer plate. did. A hole-forming auxiliary material was similarly arranged on the front and back sides, and after bonding, a via hole was formed by pulse oscillation of a carbon dioxide laser under the same conditions, and a through-hole was formed. Thereafter, the auxiliary material on the front and back was peeled off, and the thickness of the front and back was dissolved and removed to 3 μm by SUEP, and at the same time, copper foil burr was also dissolved and removed. Circuits such as pads for solder balls were formed on the front and back surfaces, and at least the semiconductor chip, bonding pads, and solder ball pads were covered with a plating resist, and nickel and gold plating were applied to produce printed wiring boards. Tables 1 and 2 show the evaluation results of this printed wiring board.

Example 2 Epoxy resin (trade name: Epicoat 1001, manufactured by 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 I was obtained by uniformly stirring and mixing. Flatness 1/4, area ratio
A paper was made in the same manner as in Example 1 using 94% of a fiber having a fiber diameter of 13 μm, impregnated so that the binder had a solid content of 7% by weight, and dried in the same manner to obtain a basis weight of 21 g / m ^2. Using a nonwoven fabric, impregnated with the varnish I, dried, gel time 120 seconds,
A prepreg J having a resin amount of 60% by weight was prepared. Further, prepreg K having a gelling time of 110 seconds and a resin amount of 78% by weight was obtained.

Using four prepregs J above and below 12 μm
m of electrolytic copper foil was placed and laminated and formed at 190 ° C., 20 kgf / cm ² and 30 mmHg to obtain a double-sided copper-clad laminate L (FIG. 2 (1)). Circuits are formed on the front and back of this board, and MM treatment (MacDermid
), And put one piece of each of the prepregs K on the outside,
A 3 μm electrolytic copper foil with a 35 μm copper foil carrier was stacked on the outside thereof, laminated and formed under the same conditions as above, and then the 35 μm copper foil carrier was peeled off to form a four-layer plate M (FIG. 2 (2)). .
On both sides, a mixture of a metal compound of Example 1 and a transparent acrylic acid ester resin having an acid value of 100 mgKOH / g was applied and dried at 120 ° C. for 20 minutes to obtain a 30 μm thick metal compound.
A coating of 65 vol% was formed. An aluminum foil with a thickness of 50 μm is placed on the back surface, and the target mark formed on the inner layer is read by a CCD camera using the same carbon dioxide laser device as in Example 1, and similarly, one shot at 30 mJ / pulse and 28 mJ / pulse Irradiate 4 shots, 120μm through hole, and 2
Irradiate one shot at 0 mJ / pulse, one shot at 10 mJ / pulse, and one shot at 30 mJ / pulse, and the hole diameter is 100μ.
A blind via hole of m was drilled (FIG. 2 (3)). The copper foil burrs remaining around the holes were dissolved and removed with an acidic etching solution while the front and back auxiliary resin layers were left, and then the front and back auxiliary layers were removed and removed with an alkaline solution (FIG. 2 (4)). A desmear treatment was performed with an aqueous solution of potassium permanganate, and copper plating was similarly performed (FIG. 3 (5)), and a printed wiring board was similarly formed (FIG. 3 (6)). The evaluation results are shown in Tables 1 and 2.

COMPARATIVE EXAMPLE 1 Using the copper-clad plate of Example 1, holes were similarly formed with a carbon dioxide gas laser without attaching anything to the surface, but no holes were formed.

Comparative Example 2 In Example 2, the surface to be irradiated with a carbon dioxide laser was coated on the copper foil surface with black magic, and the hole was drilled in the same manner, but no hole was formed.

Comparative Example 3 Glass fibers having an elliptical approximate cross-section with an aspect ratio of 4/1 and an area ratio of 75%, a converted fiber diameter of 10 μm, and a length of 13 mm were used. Was 8%, and a prepreg was prepared under the same conditions as in Example 2, and an inner layer plate was similarly formed to form a multilayer, thereby obtaining a four-layer plate. Using this, a hole was similarly drilled to obtain a printed wiring board. SUEP was not implemented. The evaluation results are shown in Tables 1 and 2.

Comparative Example 4 In Example 2, epicoat 5045 was used as the epoxy resin.
1000 parts and a glass fiber of # 1080 type (weight 48g / m ² ) using circular fiber as glass fiber, resin amount 70
The prepreg O having a gelation time of 116 seconds was obtained by impregnating and drying to give a weight%. Further, a glass fiber woven fabric having a thickness of 100 μm was impregnated and dried to prepare a prepreg P having a gelation time of 122 seconds and a resin amount of 45% by weight. Use two prepregs P,
Electrodeposited copper foil with a thickness of 12 μm on both sides at 75 ° C, 20 kgf / cm ²
For 2 hours to form a double-sided copper-clad laminate. After forming a circuit on both sides and subjecting it to black copper oxide treatment, one prepreg O was placed on each side, and 175 ° C, 20 kgf / cm ²
For 2 hours to obtain a four-layer board Q. Using this, a mechanical drill having a drill diameter of 150 μm was used to form through holes at 400 μm intervals at a rotation speed of 100,000 rpm. A desmear treatment was performed once without performing the SUEP treatment, and thereafter, copper plating was performed by a normal method to prepare a printed wiring board. The evaluation results are shown in Tables 1 and 2.

Comparative Example 5 Using the double-sided copper-clad board L of Example 2 (FIG. 4A), the upper and lower copper foils were removed by etching so that the through holes in the inner layer had a hole diameter of 100 μm. After forming the circuit, the surface of the copper foil is treated with black copper oxide, and one sheet of prepreg K is placed on the outside thereof, and a 12 μm electrolytic copper foil is placed on the outside thereof. It was created (FIG. 4 (2)). Using this multilayer plate, a hole diameter of 10
900 holes of 0 μm were formed by etching a copper foil. Similarly, 900 holes having a hole diameter of 100 μm were formed in the same position on the back surface.
Sixty shots of a total of 63,000 holes were formed from the surface by carbon dioxide laser at an output of 15 mJ / pulse, and through holes were drilled (FIG. 4 (3)). After that, in the same manner as in Comparative Example 4, without performing the SUEP treatment, a desmear treatment was performed once, copper plating was performed 15 μm (FIG. 4 (4)), circuits were formed on the front and back surfaces, and a printed wiring board was similarly formed. Created. The evaluation results are shown in Tables 1 and 2.

[0042]

[Table 1]

[0043]

[Table 2]

<Measurement Method> 1) Misalignment of the position of the front and back holes and drilling time 70 blocks (a total of 63,000 holes) were prepared in the work size of 250 mm square with 900 through holes / block. Drill holes with a carbon dioxide laser and a mechanical drill, and determine the time required to drill 63,000 holes in one copper-clad plate, the gap between the copper foil for front and back lands and the hole, and the maximum value of the gap between the inner layer copper foil. Indicated. 2) Hole wall irregularities The cross section of the hole was observed. 3) Circuit pattern breakage and short circuit In Examples and Comparative Examples, a board without holes was created, a comb pattern of line / space = 50/50 μm was created, and 200 patterns after etching were visually observed with a magnifying glass. The total number of cut and short-circuited patterns was shown in the molecule. 4) Glass transition temperature Measured by the DMA method. 5) 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. 6) Migration resistance (HAST) A total of 50 holes are connected without passing one through hole with a hole diameter of 100 μm or 150 μm (mechanical drill) alternately.
Make a total of 100 sets so that they are parallel
After a predetermined time treatment at 30 ° C., 85% RH, and 1.8 VDC, the samples were taken out and the insulation resistance between through holes arranged in parallel was measured. 7) Surface smoothness Measured with a surface roughness meter.

[0045]

According to the present invention, the cross section is flat, the flattening ratio expressed by the long diameter / short diameter of the cross section is 3.1 / 1 to 5/1, and the cross sectional area is a rectangle circumscribing the glass fiber cross section. Area of 90
~ 98%, the converted fiber diameter is 5 ~ 17μm Glass fiber non-woven fabric containing 90% by weight or more of flat glass fiber, the build-up multilayer printed wiring board obtained by using as a base material of the inner layer board and the build-up layer. Provided. The printed wiring board of the present invention has excellent surface smoothness, can reduce the thickness of the glass layer, and can increase the density of the glass fibers. Furthermore, it is suitable for drilling with a high-energy carbon dioxide laser. Preferably, 20 to 60 mJ / pulse energy is applied directly after forming an auxiliary layer on the copper foil surface and then drilling the copper foil. In addition, it is possible to form a through-hole and / or a blind via hole with less unevenness of the hole wall. Next, after removing the inner and outer layer copper foil burrs protruding in the holes by etching, performing desmear treatment as necessary, and further performing copper plating, the printed wiring board using the copper-clad multilayer board, the front and back holes There is no deviation from the land copper foil, and the processing speed can be remarkably increased as compared with drilling with a mechanical drill, the hole positioning accuracy is excellent, and the productivity can be greatly improved. In addition, by using it as a thin copper foil with a thickness of 2 to 7 μm, even in the circuit formation of the front and back copper foil obtained by plating up with subsequent copper plating, high density printing without defects such as shorts and pattern breaks It is suitable for making wiring boards and has excellent hole connection reliability. In addition, by using a polyfunctional cyanate resin composition as the thermosetting resin composition, a composition excellent in heat resistance, migration resistance and the like can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a flat glass fiber.

FIG. 2 is a process diagram of a through hole and a blind via hole (3) of a multilayer copper clad board of Example 2 by a carbon dioxide laser and a burr removal (4) by SUEP.

FIG. 3 is a process diagram of drilling a multilayer copper-clad board of Example 2 with a carbon dioxide laser, copper plating after SUEP (5), coating with a plating resist, nickel plating, gold plating, and solder ball bonding (6). is there.

FIG. 4 is a process drawing of drilling and copper plating of a multilayer copper-clad board of Comparative Example 5 with a carbon dioxide gas laser (without SUEP).

[Explanation of symbols]

a Double-sided copper-clad board b Four-layer copper-clad multilayer board c Inner-layer copper foil circuit d Flat glass fiber nonwoven fabric base thermosetting resin composition layer e Auxiliary drilling layer with carbon dioxide gas laser f Through-hole drilling with carbon dioxide gas laser Part g Via hole drilling part with carbon dioxide gas laser h Copper foil burr on outer layer blind via part i Blind via hole part after burr generated outer layer copper foil b on through hole part j Through hole part removed by etching l Via hole part plated with copper m Through hole part plated with copper n Plating resist o Solder ball p Inner layer copper foil part with shift q Copper plating of through hole with poor drilling r Surface layer Circuit s Inner layer copper foil burr generated by carbon dioxide laser drilling

──────────────────────────────────────────────────続 き Continued on the front page (51) Int. Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/00 C08K 3/00 C08L 79/04 C08L 79/04 Z 101/12 101/12 D21H 13/40 D21H 13/40 15/02 15/02 H05K 1/03 610 H05K 1/03 610T 610R 610M 3/00 3/00 N // C08J 5/24 CEZ C08J 5/24 CEZ CFG CFG F term (reference) 4F072 AA07 AB09 AB14 AB15 AB29 AB31 AD27 AD28 AD45 AF06 AG03 AH02 AH21 AJ04 AK02 AL13 4F100 AA01A AA01B AA01H AA18H AA20H AB17C AB33C AG00A AG00B AK01A EJ01B AK44A AK44B AK53A13 CA13 BA13 BA13 BA06 BA13 BA06 JG04B JG04H JJ03 JK15 JL02 YY00A YY00B YY00H 4J002 CD011 CD021 CD051 CD061 CD171 CD181 CM021 CP051 DE076 DE136 DE146 DJ005

Claims (6)

[Claims] 1. A glass fiber having a flat cross section, a flattening ratio expressed by a major axis / a minor axis of the cross section being 3.1 / 1 to 5/1, and a cross sectional area of a rectangular shape circumscribing the glass fiber cross section. Area
90 to 98%, containing 90% by weight or more of flat glass fibers having a converted fiber diameter of 5 to 17 μm, and a thermosetting resin composition layer of a glass fiber nonwoven fabric base material having a thickness of 100 μm or less as an inner layer and build-up. A build-up multilayer printed wiring board characterized by having in a layer. 2. The glass fiber non-woven fabric substrate comprises a binder.
The build-up multilayer printed wiring board according to claim 1, which contains 3 to 8% by weight. 3. The build-up multilayer printed wiring board according to claim 1, wherein the thermosetting resin composition contains 10 to 80% by weight of an insulating inorganic filler in the composition. 4. The build-up according to claim 1, wherein the thermosetting resin is a resin composition containing a polyfunctional cyanate ester compound and the cyanate ester prepolymer as essential components. Multilayer printed wiring board. 5. A build-up multilayer printed wiring board comprising an auxiliary layer for drilling a carbon dioxide gas laser on the surface of a copper-clad multilayer board, and directing a carbon dioxide laser having sufficient energy to process a copper foil from above. 5. The build-up multilayer printed wiring board according to claim 1, wherein holes having a diameter of 150 μm or less are formed by irradiation. 6. The method according to claim 1, wherein after the hole is formed by the carbon dioxide gas laser, a part of the thickness of the surface copper foil is dissolved and removed with a chemical solution, and at the same time, the copper foil burr generated around the hole is also dissolved and removed. 5. The build-up multilayer printed wiring board according to 5.