JP2002265645A - Method for producing prepreg having high filler content - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for producing a prepreg having good adhesion of a copper foil, mechanical strength and electric properties even when containing a large amount of an inorganic filler in a resin composition prepared by compounding the filler. SOLUTION: A prepreg is prepared by using a fiber cloth base material, impregnating a thermosetting resin composition comprising 10-79 wt.% of the inorganic filler thereinto and drying. The objective prepreg is produced by arranging and adhering a material obtained by adhering a composition prepared by uniformly compounding 80-99 wt.%, preferably 81-95 wt.% of the nonconductive inorganic filler having 0.30-1.00 m<2> /g of specific surface area measured by Brunauer-Emmett-Teller(BET) method on a resin composition prepared by preferably compounding (b) an epoxy resin liquid at a room temperature in an amount of 50-10,000 pts.wt. based on 100 pts.wt. of (a) a polyfunctional cyanate ester and essentially adding a thermosetting catalyst in an amount of 0.005-10 pts.wt. based on 100 pts.wt. of the (a)+(b) components as a thermosetting resin and forming B-stage on one side of a thermoplastic film so that the resin faces toward the prepreg on both sides of the prepreg. Thereby, the uniform prepreg can be produced even when having high filler content and the printed circuit board having high filler content and having excellent heat resistance, migration resistance, electric properties after moisture adsorption, adhesion to the copper foil, strength, etc., can be produced by using the prepreg.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a base material comprising 10 to 10 inorganic fillers.
Impregnated with 79% by weight of the thermosetting resin composition, dried to form a B-stage, and used an inorganic filler in the surface layer of 80 to 99% by weight. Regarding the manufacturing method, the copper-clad board obtained by using this, especially the printed wiring board obtained by drilling with a carbon dioxide laser, as a high-density small printed wiring board, mounted with a semiconductor chip, small, It is mainly used for new lightweight semiconductor plastic packages, delay elements, electronic equipment with built-in capacitors, etc.

[0002]

2. Description of the Related Art In recent years, high-density multilayer printed wiring boards have been used in electronic devices that are becoming smaller, thinner and lighter. This printed wiring board
In some cases, a large amount of an inorganic filler is added to a resin composition to prepare a prepreg for reasons such as an increase in relative dielectric constant and an improvement in heat dissipation, and this is used as a copper-clad laminate to form a printed wiring board. Can be When preparing a prepreg using a generally known base material such as a glass cloth base material, the amount of the inorganic filler in the resin composition is 80% by weight, and furthermore, when the amount is too large as 85% by weight, the base material is impregnated. When dried, it was difficult to adhere the resin composition to the surface layer of the base material, and cracks and the like occurred, so that a good prepreg could not be produced. In addition, the inorganic filler has a large specific gravity, and when it is added in a large amount as 80% by weight because of sedimentation when dispersed in a varnish, an average particle diameter of about 1 to 3 μm was used. When impregnating and drying the base material, if the concentration of the varnish is high, it is difficult to adhere to the base material, so it is diluted with a solvent to a considerably low viscosity, so that even if the particles are small, the sedimentation amount is large during impregnation, The content of the inorganic filler in the resin composition when attached to the material varied. Moreover, when a copper foil is bonded using this prepreg to form a copper-clad laminate, the adhesive strength is extremely low, and it is difficult to use a printed wiring board. Therefore, in the case of a copper-clad laminate so far, a resin composition using an inorganic filler amount of 80% by weight or more to maintain the adhesive strength of the copper foil or the like is obtained by impregnating the substrate and drying. No prepreg was used.

Further, as shown in Japanese Patent Application Laid-Open No. Hei 9-27442,
Without using a base material, a high dielectric constant film obtained by mixing a thermosetting resin and an inorganic powder having a dielectric constant of 50 or more, in order to form a film, the viscosity of the resin is high, the inorganic filler The upper limit is about 60% by weight. As a production method of attaching an inorganic filler to a substrate, the substrate is continuously flowed in a horizontal direction, a varnish containing an inorganic filler is applied on one side by knife coating or the like, and dried to a B stage, and then the opposite side is applied. Similarly, there is a method of applying a varnish and drying to prepare a prepreg as a B stage, but this causes variations in the thickness of the resin composition layer on the front and back sides, a difference in the B stage degree, and the like,
A stable product could not be produced. Further, when a high-density printed wiring board is used, migration resistance, electrical insulation after moisture absorption, and the like have been problems.

[0004]

The present invention solves the above-mentioned problems. Even if an inorganic filler is added in a large amount so as to be 80% by weight or more, the obtained prepreg remains on the front and back of the substrate. The adhered resin composition layer has almost no variation in thickness,
There is almost no variation in the content of the inorganic filler, and the laminated copper-clad laminate has high copper foil adhesion, high mechanical strength, and high processability such as high-speed small-diameter drilling by carbon dioxide gas laser. This is a production method for obtaining a method for producing a substrate reinforced thermosetting resin prepreg for printed wiring boards, which is excellent and has good hole reliability.

[0005]

According to the present invention, a fibrous cloth is used as a base material, and a thermosetting resin composition containing 10 to 79% by weight of an insulating inorganic filler is impregnated with the fibrous cloth and dried. On both sides of the staged prepreg, 80-99 of insulating inorganic filler
A B-stage resin-adhered film is prepared by adhering a thermosetting resin composition blended in a weight-% thermosetting resin to one surface of a thermoplastic film, and this is disposed on both surfaces of a prepreg, preferably heated, The prepreg is prepared by dissolving the resin layer under pressure and attaching the resin layer to the central prepreg. in this case,
The dispersion of the thickness of the B-stage resin composition layer is extremely small, and the dispersion of the content of the inorganic filler is almost non-existent, so that a homogeneous prepreg can be produced.

As the thermosetting resin to be adhered to at least the thermoplastic film, preferably, (a) a polyfunctional cyanate ester compound, the cyanate ester prepolymer
(B) 50 to 100 parts by weight of liquid epoxy resin at room temperature
10,000 parts by weight are blended, and for this (a + b) 100 parts by weight,
By using a resin composition containing 0.005 to 10 parts by weight of a thermosetting catalyst as an essential component, the resin composition layer when prepreg is used is free from brittleness, has high flexibility, and has excellent workability. Is obtained. Furthermore, a printed wiring board using the same was excellent in heat resistance, migration resistance, and electrical insulation after moisture absorption, and was obtained with good reliability.

As the inorganic filler, in particular, an insulating inorganic filler powder having a specific surface area of 0.30 to 1.00 m ² / g and an average particle diameter of 4 to 30 μm by the BET method is 80 to 99% by weight, preferably 81 to 95% by weight. weight%
By using a sheet with B-stage resin prepared by uniform mixing so that it becomes a surface layer, it is adhered to both sides of the central B-stage prepreg, integrated into a prepreg, and then used as a copper-clad laminate. Thus, a product excellent in adhesive strength to a copper foil was obtained. In this case, as the prepreg, a heat-cured C-stage can be used. In addition, since the base material is reinforced, the mechanical strength is higher than that of a copper-clad plate that does not have a base material and is also blended with a large amount of an inorganic filler. A product having excellent properties was obtained. In the processing, a small diameter hole with a diameter of 80 to 180 μm is made by direct irradiation of the copper-clad laminate with a carbon dioxide gas laser, so that through holes and / or blind via holes can be formed at high speed, and the hole shape is excellent. A highly reliable printed wiring board was obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a thermosetting resin composition layer comprising a fiber cloth base material and 10 to 79% by weight, preferably 20 to 75% by weight of an inorganic filler. Impregnated and dried B
The prepreg of the stage, on both surfaces, a thermosetting resin composition containing 80 to 99% by weight of an insulating inorganic filler was adhered to one surface of a thermoplastic film to form a B stage, and the resin side was the prepreg side. And prepreg by heating and applying pressure to the central substrate under pressure. This is used to form a copper-clad board, and drilling, copper plating, circuit formation, etc. are performed to obtain a printed wiring board. In the case of lamination molding, it is combined with a copper-clad board having another characteristic value and inserted between a power supply and a grounding layer to obtain a printed wiring board for a capacitor use, an electromagnetic wave blocking use and the like.

Attempts have been made to prepare prepregs by adding a large amount of an inorganic filler, particularly 80% by weight or more. As this method, there is a method in which an inorganic filler is blended in a varnish in which a thermosetting resin is dissolved, uniformly dispersed, and the resultant is continuously impregnated into a substrate and dried. In this method, the inorganic filler settles during the application due to its heavy weight, causing a decrease in the amount of the inorganic filler attached, causing a variation, and further heating when the B stage is used. Due to the weight of the resin composition, phenomena such as the surface resin composition layer falling during heating may occur, and a uniform prepreg cannot be produced. There is also a method in which a varnish is applied by knife coating on one side while continuously flowing a substrate in a horizontal direction, but as described above, there is a drawback.

[0010] The prepreg produced by the production method of the present invention has a uniform resin composition layer thickness on both sides.
There is almost no variation of the inorganic filler in the resin composition, and the resin composition is homogeneous. The present invention first prepares a varnish containing 10 to 79% by weight, preferably 20 to 75% by weight, of an inorganic filler in a thermosetting resin, and continuously impregnates the substrate with the varnish to form a prepreg. . The resin composition is uniformly adhered to the substrate, but in order to make the surface of the adhered resin composition smooth and uniform, the resin surface is generally rubbed with a squeeze roll, a comma roll or the like in a coating step to produce the resin composition. Is preferred. The B-stage resin composition layer is generally adhered so as to be about 1 to 10 μm from the surface of the substrate, depending on the irregularities of the substrate.

On the other hand, on one surface of the thermoplastic film, the thermosetting resin composition contains 80 to 99% by weight of an inorganic filler, preferably 81% by weight.
9595% by weight of the resin composition is applied and dried to obtain a film with a B-stage resin. The thickness of this resin layer is ± 1
Since the resin layer can be formed with an accuracy of μm, the thickness accuracy is very excellent. By arranging the resin layers on both sides of the prepreg such that the resin layers face the prepreg side and attaching the resin layers to the prepreg, it is possible to obtain a resin layer having very little variation in the resin layers on both sides of the substrate. The method of adhering is not particularly limited, but preferably, it is continuously laminated and integrated under pressure with a heating roll. The temperature of the heating roll is generally 70 to 120 ° C., and the pressure is generally 1 to 20 kgf / cm.

[0012] The prepreg obtained by the twice-adhesion method is used to fill the voids and irregularities of the fiber cloth using a squeeze roll, a comma roll, etc. in the first impregnation of the base material and the drying step. Make it a smooth sheet. This may be at the C stage, but is preferably at the B stage for better adhesion. By attaching the resin layer of the B-stage resin sheet thereon, a resin having a uniform thickness can be obtained.

In the present invention, in order to produce a copper-clad laminate having a copper foil adhesive strength and a printed wiring board using the same, the inorganic filler preferably has an average particle size of 4 to 30 μm, preferably Is 5 to ²⁰ μm, and the specific surface area by the BET method is 0.30 to 1.00 m ²
/ g, preferably 0.35 to 0.90 m ² / g. As the inorganic filler, a generally known insulating inorganic filler can be used. Specifically, silica, wollastonite, talc,
Calcined talc, titanium oxide, synthetic mica, barium titanate ceramic, lead titanate ceramic, calcium titanate ceramic, strontium titanate ceramic, magnesium titanate ceramic, bismuth titanate ceramic, lead zirconate ceramic And the like are preferably used, and at least one of them is contained, and / or one or more of these is sintered and then pulverized powder is blended. One or more of these powders may be appropriately mixed and used to obtain a desired relative dielectric constant. In addition, the inorganic filler used when adhering to the base material and the inorganic filler incorporated in the resin composition adhered to the thermoplastic film may be the same or different. Relative permittivity
In order to increase as high as 20 or more, at least the inorganic filler in the externally used thermosetting resin composition has a relative dielectric constant of 50 or more.
0 or more, preferably 2000 or more are used. Needless to say, a needle-like inorganic filler can also be used in combination.

The resin is not particularly limited. For example,
A generally known thermosetting resin such as a polyfunctional cyanate resin, a polyfunctional maleimide resin, a polyimide resin, an epoxy resin, and a double-bonded polyphenylene oxide resin is used. These are used alone or in combination of two or more. Among them, migration resistance,
From the viewpoints of heat resistance, heat resistance after moisture absorption, and the like, a polyfunctional cyanate resin is preferably used.

[0015] In order to prevent brittleness of the prepreg and increase flexibility, a liquid epoxy resin is preferably blended. The amount used is preferably (a) a polyfunctional cyanate compound, 100 parts by weight of the cyanate ester prepolymer, and (b) 50 to 10,000 parts by weight of a liquid epoxy resin at room temperature. A thermosetting resin composition containing, as an essential component, a resin composition obtained by mixing 0.005 to 10 parts by weight of a thermosetting catalyst with respect to 100 parts by weight of the (a + b) component is used.

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

In addition to these, Japanese Patent Publication Nos. 41-1928 and 43-1846
8, polyfunctional cyanate compounds described in JP-A-44-4791, JP-A-45-11712, JP-A-46-41112, JP-A-47-26853 and JP-A-51-63149 can also be used. Further, a prepolymer having a molecular weight of 400 to 6,000 and having a triazine ring formed by trimerization of a cyanato group of these polyfunctional cyanate compounds is used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer with a catalyst such as an acid such as a mineral acid or a Lewis acid; a base such as a tertiary amine such as sodium alcoholate; or a salt such as sodium carbonate. It can be obtained by: The prepolymer also contains some unreacted monomers and is in the form of a mixture of the monomer and the prepolymer, and such a raw material is suitably used for the purpose of the present invention. Generally, it is used after being dissolved in a soluble organic solvent.

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

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

The thermosetting resin composition of the present invention uses a known thermosetting catalyst. The amount used is 0.005 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the thermosetting resin. As a method of uniformly kneading the components of the present invention, generally known methods can be used. For example, after blending each component,
Knead with a three-roll mill at room temperature or under heating, or mix with a homomixer or the like. A solvent may be added so that the viscosity becomes appropriate. As the substrate, an organic or inorganic fiber cloth substrate is used. There is no particular limitation on the type,
As the organic fiber cloth, preferably, a liquid crystal polyester fiber,
Non-woven fabrics and woven fabrics such as polybenzazole fibers and wholly aromatic polyamide fibers are used. In particular, from the point of drilling,
A liquid crystal polyester nonwoven fabric is preferably used.

In the case of a non-woven fabric, a binder is attached to connect the fibers, or a fiber having a low polymerization degree and a fiber having a high polymerization degree are mixed, and the fiber having a low polymerization degree is heated and melted at a temperature of about 300 ° C. The nonwoven fabric disclosed in JP-A-11-255908, which is used in place of the binder, can be used. When a binder is used, its amount is not particularly limited. However, in order to maintain the strength of the nonwoven fabric, 3 to 8% by weight is preferably adhered. As the inorganic fiber cloth, a glass fiber woven cloth or nonwoven cloth having a generally circular or flat cross section, or a ceramic fiber woven cloth or nonwoven cloth having a relative permittivity of preferably 50 or more is used. A glass fiber nonwoven fabric having a thickness of 100 μm, preferably 50 μm or less is suitably used. As the ceramic fiber, a cloth having a dielectric constant of 50 or more, preferably 500 or more is used.

The prepreg of the present invention is laminated as it is without using copper foil, and then copper is adhered by sputtering or the like. A copper foil, preferably an electrolytic copper foil is arranged on at least one side, and laminated under heating and pressure. A copper-clad laminate is formed by a method such as molding into a copper-clad laminate. From the viewpoint of workability and copper foil adhesive strength, it is preferable to directly arrange the copper foil and perform lamination molding. The copper foil used is not particularly limited, but preferably has a thickness of 3
~ 35 μm electrolytic copper foil is used. The lamination molding conditions of the copper clad board used in the present invention are generally a temperature of 150 to 250 ° C and a pressure of 5 ° C.
5050 kgf / cm ² , time is 1-5 hours. Further, it is preferable to carry out lamination molding under vacuum.

When a through hole and / or a blind via hole is made in the copper clad board obtained in the present invention, it is preferable that a hole having a hole diameter of more than 180 μm is made with a mechanical drill.
The through holes and / or blind via holes having a size of 20 μm or more and 180 μm or less are preferably formed with a laser. 20μm
The through holes and / or blind via holes having a diameter of less than 80 μm are preferably formed by an excimer laser or a YAG laser. Furthermore, through holes and / or blind via holes of 80μm or more and 180mμ or less, or subjected to a chemical treatment on the copper foil surface,
Whether an auxiliary material consisting of a metal compound powder, a carbon powder, or a resin composition containing one or more metal powders having a melting point of 900 ° C. or higher and a total bond energy of compound atoms of 300 kJ / mol or higher is determined. It is preferable to form a cobalt or nickel metal layer or an alloy layer thereof on the shiny surface of the copper foil, and then directly irradiate the carbon dioxide laser directly to form the holes. Of course, other generally known drilling methods can be used.

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

Since the molecules are dissociated or melted and scattered by the irradiation of the carbon dioxide laser, the metal adheres to the hole walls and the like, and does not adversely affect the semiconductor chip and the hole wall adhesion. preferable. Since Na, K, Cl ions and the like particularly adversely affect the reliability of the semiconductor, those containing these components are not suitable. The compounding amount is 3 to 97 vol%, preferably 5 to 95 vol%, and is preferably mixed with the water-soluble resin and uniformly dispersed. The water-soluble resin of the auxiliary material is not particularly limited, but a resin that does not peel off when kneaded and applied to the surface of the copper foil and dried or when formed into a sheet is selected. For example, generally known materials such as polyvinyl alcohol, polyester, polyether and starch are used.

The method for preparing the metal compound powder, carbon powder, or the composition comprising the metal powder and the resin is not particularly limited, but is kneaded at a high temperature without a solvent using a kneader or the like, and extruded into a sheet on a thermoplastic film. A method of dissolving a water-soluble resin in water, adding the powder to the mixture, stirring and mixing the mixture uniformly, and applying the mixture to a thermoplastic film as a paint, followed by drying to form a film. And other generally known methods. The thickness is not particularly limited, but is generally used in a total thickness of 30 to 200 μm. In addition, it is also possible to perform a chemical solution treatment on the surface of the copper foil and then similarly drill holes. The treatment is not particularly limited, but for example, treatment with a chemical solution marketed by Mec (treatment name: CZ treatment)
Etc. can be suitably used. On the back side, it is preferable to use a backup sheet in which a water-soluble resin is adhered on a metal plate on the back side in order to avoid damage to the table of the carbon dioxide laser when the through-hole is formed.

The auxiliary material is applied as a coating film on the copper foil surface, or is applied on a thermoplastic film to form a sheet. When heating the sheet to the copper foil surface, laminating under pressure, the auxiliary material, the backup sheet together with the applied resin layer toward the copper foil surface, with a roll, the temperature is generally 40 ~ 150 ℃, preferably 60 ~ 120 ℃ , The linear pressure is generally 1-20 kgf / cm, preferably
Lamination is performed under a pressure of 2 to 10 kgf / cm, and the resin layer is melted and brought into close contact with the copper foil surface. The selection of the temperature depends on the melting point of the water-soluble resin used, and also depends on the linear pressure and the laminating speed.
Laminate at high temperature.

The copper foil of the present invention has a shiny surface treated with a cobalt or nickel metal or a nickel alloy (cobalt, nickel).
Those which have been subjected to a generally known alloy treatment with zinc, iron or the like are preferably used. CO2 laser, preferably output 5
~ 60mJ irradiation to form a hole with a hole diameter of 80-180μm,
Burrs occur around the holes. This is not a particular problem in a double-sided copper-clad laminate with a thin copper foil, and the resin remaining on the copper foil surface is removed by gas phase or liquid phase treatment, and copper plating inside the hole is performed as it is. More than 50% of the inside of the hole can be plated with copper, and the surface layer can be plated at the same time to make the thickness of the copper foil 18 μm or less. However, preferably, an etching solution is sprayed or sucked through the hole to dissolve and remove the overhanging copper foil burrs, and at the same time, the thickness of the surface copper foil is 2
~ 7μm, preferably 3 ~ 5μm to etch,
Perform copper plating. In this case, etching with a chemical solution is more preferable than mechanical polishing in terms of removing burrs from holes, dimensional change due to polishing, and the like.

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
488, a method of dissolving and removing a metal surface with a chemical (SUEP method: Surface Uniform Etching Process method). The etching rate is generally 0.02 to 1.0 μm / sec.

As the carbon dioxide laser for forming holes, a wavelength of 9.3 to 10.6 μm in the infrared wavelength range is generally used. Excimer laser has a wavelength of 248 to 308 nm, YAG laser has a wavelength
351-355 nm is commonly used, but is not limited. The processing speed of the carbon dioxide laser is remarkably fast and economical.

[0031]

The present invention will be specifically described below with reference to examples and comparative examples. Unless otherwise specified, “parts” indicates parts by weight. Examples 1 to 5 2,2-bis (4-cyanatophenyl) propane monomer (component
1,000 parts of A-1) were melted at 150 ° C., and reacted with stirring for 4 hours to obtain a prepolymer having an average molecular weight of 1,900 (component A-2). As a liquid epoxy resin at room temperature, bisphenol A type epoxy resin (trade name: Epicoat 828, manufactured by Japan Epoxy Resin Co., Ltd., component B-1), bisphenol F type epoxy resin (trade name: EXA830LVP, Dainippon Ink & Chemicals, Inc.) Industrial B. component B-2), novolak type epoxy resin (trade name: DEN431, manufactured by Dow Chemical Co., Ltd., component B-)
3), Cresol novolak type epoxy resin (trade name: ESC)
N220F, Sumitomo Chemical Co., Ltd., component B-4), Br-modified phenol novolak type epoxy resin (brand name: BREN-S, Nippon Kayaku Co., Ltd., component B-5), and heat cured Iron acetylacetone (component C-1), 2-ethyl-4-methylimidazole (component C-2) as a catalyst, and epoxysilane coupling agent (trade name: A-187, Nippon Yunika Co., Ltd.) as an additive
A varnish was prepared by blending a component D-1) and dicyandiamide (component E-1). Barium titanate-based ceramics (relative permittivity at 1 MHz at room temperature: 2,01) as an insulating inorganic filler
0, specific surface area 0.41 m ² / g, component F-1), bismuth titanate-based ceramic (relative permittivity at room temperature: 733, specific surface area)
0.52 m ² / g, component F-2), barium titanate-calcium stannate ceramic (relative permittivity at room temperature: 5,020, specific surface area 0.45 m ² / g, component F-3), dioxide Using a titanium-based ceramic (dielectric constant at room temperature: 30, specific surface area: 0.92 m ² / g, component F-4), mix as shown in Table 1 and knead uniformly with a homomixer for 10 minutes. The varnish having a high viscosity had a viscosity appropriate for application by adding a small amount of methyl ethyl ketone, and the sedimentation of the inorganic filler was extremely slow. This varnish was continuously coated on one side of a substrate and a 50 μm thick polyethylene terephthalate (PET) film with a thickness of 4 μm.
Coated and dried to 0 ~ 50μm, 170 ℃, 20kgf / c
A resin sheet Z which was B-staged such that the resin flow in 5 minutes at m ^{2 was 2} to 20 mm was prepared.

The base material has a fiber diameter of 13 μm and a length of 16 mm
The liquid crystal polyester fibers, dispersed in polyethylene oxide dispersion solution, creating an adhesive solution basis weight using epoxy resin emulsion and a silane coupling agent in papermaking and nonwoven such that 30 g / m ^2, which 6 Non-woven fabric G obtained by adhering to a weight% and drying at 150 ° C., aspect ratio 4 /
1, an area ratio of 92%, a converted fiber diameter of 10 μm, a length of 13 μm, a nonwoven fabric H having a basis weight of 15 g / m ² , obtained by adhering a binder and a silane coupling agent in the same manner, a fiber diameter of 1
A nonwoven fabric I made in the same manner as above using ceramic fibers having a size of 1 μm, a length of 14 μm, and a relative dielectric constant of 1,320, a glass woven fabric J having a thickness of 20 μm and a weight of 17 g / m ² were impregnated and dried to obtain a B stage. On both surfaces of these prepregs, a resin sheet Z was arranged so that the resin layer faced the prepreg side, laminated at 100 ° C. and rolled at 5 kgf / cm to form a B-stage prepreg, and then cut into 530 × 530 mm. .

The PET film of the B-stage prepreg was peeled off, and three PET films were used. A general electrolytic copper foil (JTC-LP, manufactured by Japan Energy Co., Ltd.) of 12 μm was placed on both sides of the PET film at 200 ° C. and 20 kgf. / cm ^2, and 2 hours laminate molded under vacuum below 30 mmHg, to obtain a double-sided copper-clad laminate. On the other hand, 800 parts of black copper oxide powder (average particle diameter: 0.8 μm) as a metal oxide powder was added to a varnish obtained by dissolving polyvinyl alcohol powder in water,
Stir and mix uniformly. This was applied on one side of a PET film having a thickness of 50 μm so as to have a thickness of the resin composition solid content of 30 μm, and dried at 110 ° C. for 30 minutes to obtain a metal compound powder content of 45 v
ol% of auxiliary material P was prepared. This varnish is applied on one side of a 50 μm thick aluminum foil to a thickness of 20% of the solid content of the resin composition.
It was applied to a thickness of μm and dried in the same manner to prepare a backup sheet Q. The auxiliary material P on the upper side of the double-sided copper-clad laminate, the backup sheet Q on the lower side, disposed so that the resin surface faces the copper foil side, and laminated at 100 ° C., 5 kgf / cm, and the hole diameter is 100 μm. Four shots of 30 holes in a 20 mm square were directly irradiated with a carbon dioxide laser at an output of 30 mJ,
A 0-block through-hole was made, and a SUEP treatment was performed to dissolve the copper foil burrs and to dissolve and remove the surface copper foil to 3 μm. Copper plating 15μm adhered, circuit (line / space = 50 / 50μm), solder ball land, etc. are formed on both sides by the existing method, excluding at least semiconductor chip mounting part, bonding pad part, solder ball pad part And covered with a plating resist to prepare a printed wiring board. Table 2 shows the evaluation results.

Comparative Example 1 In Example 5, a varnish having an inorganic filler amount of varnish No. was used, a little methyl ethyl ketone was added to lower the viscosity, and all the others were the same. An attempt was made to prepare a prepreg having a thickness, but the attached resin composition layer was sagged, cracked, and non-uniform.

Comparative Example 2 Using the varnish of Example 1, a varnish was applied to the surface of the substrate H by knife coating so that the dried resin layer had a thickness of 50 μm while flowing the substrate H in the lateral direction. Then, the resin was continuously placed in a horizontal dryer and dried to obtain the B stage. However, resin fell from gaps in the nonwoven fabric, and voids were found in some places. This was rolled up, applied and dried on the opposite surface in the same manner, but the voids were not completely filled, and only prepregs with gaps were formed. Using these three sheets, laminate molding was carried out in the same manner as in Example 1, but many voids were generated and the characteristics could not be measured.

Comparative Example 3 In Example 2, the polyfunctional cyanate component (A-
Instead of 1,2) and the epoxy resin component (B-3), 75 parts of a brominated epoxy resin (trade name: Epicoat 5045, manufactured by Japan Epoxy Resin Co., Ltd.), and the other components are the same, 3.5 parts of dicyandiamide, 0.1 part of ethyl imidazole was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and the mixture was stirred and mixed to uniformly disperse, thereby obtaining a varnish M (this solid is referred to as Component B-6). Using this, as an inorganic filler, F-2 of Example 2 was mixed with 900 parts of the same solid component B-6 as in Example 2 with respect to 100 parts of solid component B-6. Apply varnish twice on each side with coating,
After drying, a B-stage prepreg was prepared. In this case, since the inorganic filler material is 90% by weight and the resin is also solid at room temperature, the resin composition layer is brittle, and a part of the resin composition on the first B-staged surface when the back surface is applied. It fell off. In addition, although the gap between the fibers was not as large as that of the glass nonwoven fabric, a prepreg having a gap was not able to partially fill the voids with the resin composition. From this, it was found that good prepreg could not be obtained by this coating method. Remove the resin from the prepreg where there is no resin, and remove the voids.
Three sheets, 12μm electrolytic copper foil placed on both sides, 180
℃, 30kgf / cm ^2, and 2 hours laminate molded under vacuum below 30 mmHg, to prepare a copper-clad laminate. Using this, a printed wiring board was similarly formed. Table 2 shows the evaluation results.

COMPARATIVE EXAMPLE 4 In Example 1, the barium titanate-based ceramic was a powder having a particle diameter of 0.5 to 5 μm, an average particle diameter of 1.3 μm, and a specific surface area B
Example 1 with an ET value of 1.29 m ² / g and a relative dielectric constant of 2,010 (referred to as F-5)
Varnish was added, a solvent was added, and the mixture was uniformly kneaded. This was applied to glass nonwoven fabric H by knife coating in the same manner as in Comparative Examples 2 and 3, and dried to prepare a B-stage prepreg. Also in this case, when the coating and drying were performed, a small gap was generated in the gap of the glass woven fabric. A portion having good coating was selected, four of them were used, and a 12 μm electrolytic copper foil was arranged on both surfaces thereof, and laminated and formed under the same conditions as in Example 1. 190
The laminate was molded by lamination under a vacuum of 20 ° C., 20 kgf / cm ² and 30 mmHg for 2 hours to prepare a double-sided copper-clad laminate. This copper-clad laminate had extremely low copper foil adhesive strength, and there were places where the copper foil peeled off during the preparation of the printed wiring board. Drill holes with a carbon dioxide laser in the same manner as in Example 1, dissolve and remove copper foil burrs with a chemical solution, dissolve the surface copper foil vertically to 3 μm, attach copper plating to 15 μm, and use this Similarly, a printed wiring board was prepared. Table 2 shows the evaluation results.

Comparative Example 5 A titanium dioxide ceramic powder (specific surface area BET value 1.45 m ² / g, relative dielectric constant 30, component F-6) was added to the varnish containing no inorganic filler of Example 2. This was mixed well with a homomixer stirrer, and then impregnated into glass woven fabric J and dried to obtain a prepreg. It has 70 weight of inorganic filler
% And a good prepreg. Using this four sheets, placed on both sides of the electrolytic copper foil with a copper carrier of 3μm, laminated and molded under the same conditions as in Comparative Example 3, and a double-sided copper-clad laminate, peeling the copper foil of the carrier, A 100 μm aluminum foil was placed on the upper side, and a paper phenol laminate having a thickness of 1.6 mm was placed on the lower side. A 100 μm through hole was made with a mechanical drill, and copper plating was adhered to 15 μm, similarly to obtain a printed wiring board. Table 2 shows the evaluation results.

Comparative Example 6 The prepreg of Example 3 obtained by using the varnish to which the inorganic filler of Example 3 was added was used.
A 2 μm copper foil was placed and laminated and molded in the same manner to prepare a double-sided copper-clad laminate. Using this, a hole of 100 μm was made with a mechanical drill in the same manner as in Comparative Example 5. In this case, there was almost no copper foil burr at the hole. The thickness of the copper foil was reduced with a chemical solution,
1.7 μm was melted in the vertical direction of the copper foil, and the remaining thickness was about 10 μm. When the surface copper foil is dissolved any more, the copper foil in the hole is also dissolved and removed in the horizontal direction, the copper foil in the hole is insufficient when copper plating is performed, and the reliability is inferior. Copper plating was applied to the entire surface by 15 μm, and a printed wiring board was similarly formed. Table 2 shows the evaluation results. in this case,
The thickness of the copper foil on the surface layer is about 25 μm, and a short circuit or pattern break in a fine circuit is more likely to occur than in the case of dissolving the copper foil on the surface layer to 3 μm in the example and then applying copper plating of 15 μm.

Comparative Example 7 The varnish of Example 5 was used, and the varnish was coated on a matte surface of a 12 μm-thick electrolytic copper foil and dried repeatedly to form a varnish having a thickness of 350 μm.
It was a resin composition layer of μm. 12 μm on this resin composition
m of electrolytic copper foil was placed and laminated and formed at 200 ° C., 30 kgf / cm ² , and a vacuum of 30 mmHg or less to obtain a double-sided copper-clad laminate. Using this, the through hole was similarly drilled with a carbon dioxide gas laser in the same manner as in the example, and the copper foil burrs generated in the holes were dissolved and removed with a chemical solution, and the copper foil was vertically removed in the thickness direction. It was melted down to 3 μm, copper plating was applied to 15 μm, and a printed wiring board was similarly formed. Table 2 shows the evaluation results.

[0041]

[Table 1]

[0042]

[Table 2]

<Measurement method> 1) Void after lamination molding The copper foil of the lamination-molded copper clad laminate was removed by etching, and voids were visually observed. 2) Copper foil adhesive strength The adhesive strength of the copper foil of the copper-clad laminate was measured according to JIS C6481. 3) Glass transition temperature Measured by the DMA method of JIS C6481. 4) Dielectric constant Measured with an LCR meter and calculated by calculation. 5) Tensile strength Measured according to JIS C6481. 6) Drilling through holes Mechanical drilling, CO2 laser drilling, hole diameter 10
70 blocks with 0 μm holes as 900 holes / block (6 holes total)
(3,000 holes) The time required to make a through hole was measured. The mechanical drill (drilling B) and the carbon dioxide laser drilling (drilling A) are both stacked one by one. 6) Cut and short circuit pattern After making a comb pattern of line / space = 50 / 50μm in the examples and comparative examples, visually observe 200 patterns after etching with a magnifying glass, and cut and short the pattern. The sum of the patterns is shown in the numerator. This is because, when drilling with a carbon dioxide gas laser, copper foil burrs are generated around the holes, so a SUEP treatment with a chemical solution is performed to remove the burrs on the copper foil and make the thickness of the surface copper foil 3 to 5 μm. After that, when copper plating is applied to the entire 15μm, the surface copper thickness becomes 18-20μ
When a fine pattern having a line / space of 50/50 μm is created using this, connection (short circuit) between the copper foil circuits or breakage of the pattern does not occur. If the surface copper foil is not thinned by dissolving it with a chemical,
When a 12 μm copper foil is applied, the total thickness becomes 27 μm in the case of a 12 μm copper foil, so that pattern cutting and short-circuiting (connection) increase in the creation of a fine pattern by general etching. 7) Through-hole heat cycle test
Drilled in the same manner as in the comparative example, performed chemical treatment, and created a land diameter of 300 μm in each of the copper-plated through holes.
900 holes were connected alternately on the front and back, and one cycle was performed up to 150 cycles at 260 ° C, silicone oil, immersion for 30 seconds → room temperature for 5 minutes, and the maximum rate of change in resistance was shown. 8) Insulation resistance value after pressure cooker process Create a comb pattern between terminals (line / space = 50 / 50μm), and place one prepreg on each
After arranging and laminating, heat-treated at 121 ° C and 203kPa for a predetermined time, post-processed at 25 ° C and 60% RH for 2 hours, charged by applying 500VDC for 60 seconds, and then insulated between terminals. The resistance was measured. 9) Migration resistance The test piece of 6) was constantly applied with 50 VDC in an atmosphere of 85 ° C. and 85% RH, and the insulation resistance between the terminals was measured. 10) HAST measurement A copper-plated through-hole with a hole diameter of 100 μm is connected alternately on both sides alternately.
Make a total of 100 sets so that
After being treated at 0 ° C., 85% RH and 1.8 VDC for a predetermined time, the sample was taken out, and the insulation resistance between the through holes arranged in parallel was measured after charging at 500 VDC for 60 seconds. 11) Primary coating, secondary coating ・ Primary coating: A varnish of varnish No.,. The gel time of the resin is set to 60 to 120 seconds (at 170 ° C.), and the resin composition is applied so as to fill the voids of the fibers of each base material, and is applied 1 to 10 μm thicker from the front and back of the base material.・ Second application: A varnish is applied on one side of a polyethylene terephthalate film having a thickness of 50 μm and dried, and a resin composition layer thickness of 40 to 50 μm and a gel time of 30 to 100 seconds (a
(t170 ° C), a film with a B-stage resin was prepared, and this was placed on both sides of the prepreg obtained by the first application so that the resin composition layer faced the prepreg side, and continuously heated with a 100 ° C heating roll. Laminated at 5 kgf / cm and integrated to form a prepreg. 12) Specific surface area Measured by the BET method. 13) Average particle diameter Measured by a laser diffraction method.

[0044]

According to the present invention, a resin composition obtained by blending a thermosetting resin composition with an insulating inorganic filler in an amount of 10 to 79% by weight is adhered to a fiber cloth base material, and a B-stage prepreg is used. Insulating inorganic filler 80 in thermosetting resin on one side
9999% by weight of the resin composition is applied, and the B-staged resin composition layer is arranged and bonded so that the prepreg side faces the prepreg side. A good base material-containing prepreg having a very large filler content could be produced. Furthermore, as an inorganic filler to be adhered to at least one surface of the thermoplastic film, the relative dielectric constant is 50 or more, preferably 500 or more, the specific surface area by the BET method is preferably 0.30 to 1.00 m2 / g, and the average particle diameter is 4
By using one having a thickness of 3030 μm, a copper-clad board excellent in adhesion to a copper foil was obtained. Further, as a thermosetting resin composition, preferably, (a) a polyfunctional cyanate ester monomer, 100 parts by weight of the cyanate ester prepolymer, (b) 50 to 10,000 weight-% liquid epoxy resin at room temperature Parts (a + b) component and 100 parts by weight of a thermosetting catalyst.
By using a resin component blended in an amount of 0.005 to 10 parts by weight as an essential component, a resin excellent in heat resistance, electrical insulation after moisture absorption, and the like was obtained. In addition, a dielectric constant of 20 or more could be obtained, and a useful one as a capacitor or the like could be produced. In addition, by using the drilling auxiliary layer on the copper-clad laminate, it is possible to directly drill small-diameter holes by irradiating a high-energy carbon dioxide laser to obtain a high-density printed wiring board. I was able to.

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Claims (4)

[Claims] 1. A prepreg having a B-stage formed by adhering a resin composition in which an insulating inorganic filler is blended in a thermosetting resin composition in an amount of 10 to 79% by weight to a base material, and one side of a thermoplastic film 80 Insulating inorganic filler powder in thermosetting resin
A high-filling method characterized in that a resin composition layer having a B-stage obtained by adhering a resin composition containing up to 99% by weight is arranged and bonded so that the resin layer faces the prepreg side and integrated. Production method of dosage prepreg. 2. The thermosetting resin, wherein at least the resin composition formed on the thermoplastic film is (b) based on 100 parts by weight of the polyfunctional cyanate ester monomer and the cyanate ester prepolymer, ) Epoxy resin 50 ~ liquid at room temperature
The high filler content according to claim 1, wherein a resin composition obtained by mixing 10,000 parts by weight and 0.005 to 10 parts by weight of a thermosetting catalyst with respect to 100 parts by weight of (a + b) is an essential component. Method for producing prepreg. 3. The method according to claim 1, wherein the insulating inorganic filler powder of the resin composition adhered on one surface of the thermoplastic film is at least one of a barium titanate-based ceramic, a strontium titanate-based ceramic, a lead titanate-based ceramic, and a calcium titanate-based powder. 3. An inorganic powder comprising at least one of ceramic, bismuth titanate-based ceramic, and lead zirconate-based ceramic, and / or a powder obtained by sintering at least one of these and pulverizing the powder. A method for producing a prepreg having a high dielectric constant and a high filler content. 4. The resin composition layer formed on at least one surface of the thermoplastic film has an average particle diameter of the insulating inorganic filler of 4 to 30 μm and a specific surface area of 0.30 to 1.00 m by a BET method.
4. The method for producing a prepreg having a high filler content according to claim 1, wherein 80 to 99% by weight of a prepreg having a content of ² / g is blended.