JP2016023294A - Resin film-provided prepreg and metal-clad laminate and printed wiring board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin film-provided prepreg having a low water absorption rate and being excellent in heat resistance, and to provide a metal-clad laminate and a printed wiring board.SOLUTION: A resin film-provided prepreg consists of a prepreg formed by impregnating glass cloth with a thermosetting resin composition and drying and a resin film containing fluorine atoms on one or both sides of the prepreg. The thermosetting resin composition contains an epoxy resin. The resin film containing fluorine atoms is composed of a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) or a fluoroethylene-vinyl ether alternate copolymer.SELECTED DRAWING: None

Description

  The present invention relates to a prepreg with a resin film suitable as a printed wiring board material, a metal-clad laminate using the same, and a printed wiring board.

  Along with the downsizing and high performance of electronic devices, printed wiring boards mounted therein are increasing in density by increasing the number of layers, reducing the thickness, reducing the diameter of through-holes, and reducing the interval between holes. Furthermore, printed wiring boards mounted on portable information terminal devices such as mobile phones and mobile computers include plastic packages in which a microprocessing unit (MPU) is directly mounted on a printed wiring board and printed wiring boards for various modules. Therefore, it is required to process a large amount of information at high speed. Therefore, high-speed signal processing, low transmission loss, and further downsizing have become necessary, and printed wiring boards are becoming increasingly denser and require finer wiring than ever before. .

  Due to the circumstances as described above, a printed wiring board for mounting an MPU or a printed wiring board for a module is required to have a material having excellent heat resistance in order to ensure connection reliability higher than ever. I came.

  In addition, with the rapid increase in interest in environmental issues in recent years, there is a growing tendency to use lead-free solder that does not contain lead as the solder used in printed wiring boards. Since the melting point is higher than that of the conventional solder, the solder reflow temperature at the time of mounting the component of the printed wiring board tends to be higher than that at the time of using the conventional lead-containing solder. Therefore, more excellent heat resistance is required for materials used for printed wiring boards. As a technique for improving heat resistance, reducing the water absorption rate can be mentioned. As a conventional method, a method of increasing the amount of filler and reducing the organic resin component ratio has been taken (see Patent Document 1). However, the above method has a limit in reducing the moisture absorption rate.

JP 2011-219770 A

  In view of the above, an object of the present invention is to provide a prepreg with a resin film, a metal-clad laminate, and a printed wiring board, which are suitable as a printed wiring board material having a lower water absorption rate and superior heat resistance. And

  The gist of the prepreg with a resin film according to the present invention for achieving the above object is that a resin film containing a fluorine atom is disposed on at least one surface of the prepreg.

The present invention relates to [1] a prepreg with a resin film, wherein a glass film is impregnated with a thermosetting resin composition and a resin film containing fluorine atoms is disposed on both surfaces or at least one surface of a prepreg formed by drying. It is.
Moreover, this invention is a prepreg with a resin film as described in said [1] in which a [2] thermosetting resin composition contains an epoxy resin.
[3] The present invention provides [3] wherein the resin film containing a fluorine atom is a film of tetrafluoroethylene / hexafluoropropylene copolymer (FEP) or a fluoroethylene / vinyl ether alternating copolymer. 2] is a prepreg with a resin film.
The present invention also provides [4] the prepreg with a resin film according to any one of the above [1] to [3] as a single layer or by laminating two or more sheets, and a metal foil on one side or both sides thereof. Is a metal-clad laminate obtained by placing and heating and pressurizing this.
Moreover, this invention is a printed wiring board formed by forming wiring using the metal-clad laminated board of [5] said [4].

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide a prepreg with a resin film, a metal-clad laminate, and a printed wiring board, which are suitable as a printed wiring board material having a lower water absorption rate and superior heat resistance than before.

The present invention is a prepreg with a resin film in which a glass film is impregnated into a glass cloth and dried, and a resin film containing fluorine atoms is disposed on both surfaces or at least one surface of the prepreg. In the present invention, the thermosetting resin composition is a resin composition containing a thermosetting resin.
Hereinafter, embodiments of the present invention will be described in detail.
Although it does not specifically limit as a thermosetting resin used for this invention, For example, an epoxy resin type | system | group, a triazine resin type | system | group, a phenol resin type | system | group, a melamine resin type | system | group, a polyester resin type | system | group modified | denatured these are mentioned. Two or more of these resins may be used in combination.
In view of versatility and cost, it is preferable to use an epoxy resin. The type of epoxy resin is preferably (a) one having two or more epoxy groups in the molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic Type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, diglycidyl etherified product of polyfunctional phenol, diglycidyl etherified product of polyfunctional alcohol, halides thereof, hydrogenation thereof There are things, and several types can be used together. A high Tg is effective for improving heat resistance, and a novolac type epoxy resin such as a phenol novolac type epoxy resin, a cresol novolak type epoxy resin, a bisphenol A novolak type epoxy resin, or a diglycidyl etherified product of a polyfunctional phenol. Etc. are preferable.

The resin film containing fluorine atoms used in the present invention is made of a fluororesin containing fluorine atoms. These fluororesins include tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene copolymer (ETFE), and polyvinylidene fluoride. Ride (PVDF), Polychlorotrifluoroethylene copolymer (PCTFE), Chlorotrifluoroethylene / ethylene copolymer (ECTFE), Fluoroethylene / vinyl ether alternating copolymer (FEVE), Fluoroethylene / vinyl ester copolymer (4F-FEVs), trifluoroethylene / vinyl ester copolymers (3F-FEVs), amorphous fluororesin (CYTOP, manufactured by Asahi Glass Co., Ltd.) and the like.
These fluororesins are preferably thermoplastic resins having not only adhesiveness but also excellent heat resistance and hygroscopic properties. In particular, tetrafluoroethylene / hexafluoropropylene copolymer resin (FEP), fluoroethylene / vinyl ether alternating copolymer (FEVE), and amorphous fluororesin (CYTOP) are more preferable as the fluororesin in view of the above characteristics.
Therefore, for example, a metal foil, preferably a copper foil, can be bonded to the surface of a prepreg on which a resin film made of a fluororesin is deposited using the resin film as an adhesive. Laminate) can be obtained.

  In addition to the said thermosetting resin, it is preferable to mix | blend an inorganic filler with the thermosetting resin composition used by this invention. It is preferable that the compounding quantity of an inorganic filler is 15-35 mass% with respect to the total solid in a resin composition. If the blending amount of the inorganic filler is less than 15% by mass, the heat resistance of the resin composition tends to be inferior, and if it exceeds 35% by mass, the fluidity of the resin composition is reduced and the moldability during pressing is reduced. There is a tendency.

  The inorganic filler is not particularly limited. For example, calcium carbonate, alumina, mica, aluminum carbonate, aluminum hydroxide, magnesium silicate, aluminum silicate, silica, talc, short glass fiber, aluminum borate, and silicon carbide. Various whiskers such as can be used. These may be used in combination. From the viewpoint of heat resistance, it is preferable to use silica, and from the viewpoint of improving characteristics, it is preferable to use aluminum hydroxide and silica in combination.

  In the present invention, it is preferable that 80% by mass or more of the inorganic filler is silica. Silica is preferably spherical silica from the viewpoint of moldability and workability of the metal-clad laminate. Moreover, it is preferable that the average particle diameter of a silica is the range of 0.4-5 micrometers. In particular, when the average particle diameter of the silica is in the range of 1 to 5 μm, it is very preferable for achieving both the heat resistance and the adhesive strength of the composition. In addition, when emphasizing workability at the time of drilling, it is preferable that the average particle diameter of silica is in the range of 0.4 to 0.7 μm. However, when the average particle size of silica is less than 0.4 μm, the varnish is remarkably thickened, the workability tends to be lowered, and the adhesive strength to the metal foil tends to be lowered. On the other hand, when the average particle diameter exceeds 5 μm, the amount of wear of the drill blade increases during drilling, and the hole position accuracy when drilling small diameters tends to deteriorate. Furthermore, problems such as chipping tend to occur. Moreover, it is preferable that the moisture content of a silica is 0.04 mass% or less. When the moisture content of silica exceeds 0.04% by mass, the silica is likely to agglomerate, the problem of appearance of the metal foil-clad laminate tends to occur, and the heat resistance tends to be inferior. The spherical silica can be obtained by a known synthesis method such as the method described in JP-A No. 61-17416. Synthetic silica is commercially available from Admatechs Co., Ltd., Electrochemical Industry Co., Ltd., Micron Co., Ltd., Tonen Co., Ltd., etc., and these can be suitably used. The average particle size can be measured using a commercially available laser light scattering particle size distribution measuring device or the like.

  As a method for blending the inorganic filler, a conventionally known technique can be used, and is not particularly limited. For example, a method using a kneader or a method disclosed in International Publication No. 97/01595 can be used. .

  In addition, the thermosetting resin composition used in the present invention may contain additives such as known curing agents, curing accelerators, flame retardants, colorants, antioxidants, reducing agents, and UV opaque agents as necessary. An appropriate amount may be added. In particular, when (a) an epoxy resin having two or more epoxy groups in the molecule is used as the thermosetting resin, it is preferable to blend a curing agent, for example, conventionally known dicyandiamide, diaminophenylmethane, Polyfunctional phenols such as diaminophenylsulfone, phthalic anhydride, pyromellitic anhydride, phenol novolac and cresol novolac can be used, and several of these can be used in combination. Considering heat resistance and reliability, it is preferable to use (b) a polycondensate of phenols and formaldehyde. The polycondensate of phenols and formaldehyde is preferably one having two or more phenolic hydroxyl groups in the molecule, such as phenol, cresol, alkylphenol, catechol, bisphenol A, bisphenol F, bisphenol S, etc. Examples thereof include novolak resins and their halides, and these may be used in combination. In addition, a compound containing a phenolic hydroxyl group other than a polycondensate of phenols and formaldehyde may be used in combination, but also in that case, it is preferable to use a compound having two or more phenolic hydroxyl groups in the molecule. . In addition, it is preferable to use a halide of a compound having two or more phenolic hydroxyl groups in the molecule because flame retardancy can be imparted. The blending amount of the curing agent may be appropriately determined according to the type and blending amount of the thermosetting resin used in the resin composition used in the present invention, and is not particularly limited, but the curing agent includes phenols and formaldehyde. When using a polycondensate and a compound having a phenolic hydroxyl group that can be used in combination, the compound may be blended so that the phenolic hydroxyl group is 0.8 to 1.2 equivalents relative to the epoxy group of the epoxy resin to be used. Preferably, it is blended so as to be 0.9 to 1.1 equivalents.

  Moreover, imidazoles etc. are mentioned as a hardening accelerator. These may be used alone or in combination of two or more.

  Moreover, it is preferable that the thermosetting resin composition used by this invention is the range whose nitrogen content in a resin component is 0.1-10 mass% from a heat resistant viewpoint, and is 0.1-5 mass%. More preferably, it is the range. As the nitrogen-containing compound, it is preferable to include (c) a resin having a triazine ring or an isocyanuric ring. Although not particularly limited, for example, cyanurates, melamines, condensation products of phenols and compounds having a triazine ring and aldehydes, and glycidyl etherified products thereof, isocyanurates, isocyanurate type epoxy resins, and the like Or in combination of two or more. The component (c) is preferably blended so that the nitrogen content in the resin component is within the above range.

  The thermosetting resin composition used in the present invention is preferably used as a varnish by dissolving the thermosetting resin, the inorganic filler, and various additives added as necessary in an organic solvent.

  Examples of the organic solvent include, but are not limited to, acetone, xylene, methyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, quinoline. , Cyclopentanone, m-cresol, and chloroform. These may be used alone or in combination of two or more. The solid content concentration in the varnish is not particularly limited and can be appropriately changed depending on the composition of the resin composition, the blending amount of each composition, and the like, but is preferably in the range of 50 to 85% by mass. If the solid content concentration in the varnish is less than 50% by mass, the varnish viscosity becomes small and the resin content when impregnated in the prepreg may be low. If it exceeds 85% by mass, the viscosity of the varnish is increased. As a result, the appearance of the prepreg tends to deteriorate.

  Moreover, in order to make the workability | operativity at the time of preparation of the thermosetting resin composition used by this invention, and the application | coating workability | operativity at the time of use better, a diluent can be added as needed. Examples of such diluents include, for example, butyl cellosolve, carbitol, butyl cellosolve, carbitol acetate, ethylene glycol diethyl ether, α-terpineol, an organic solvent having a relatively high boiling point, PGE (phenylglycidyl ether, Nippon Kayaku Co., Ltd.). Manufactured), PP-101 (alkyl phenyl glycidyl ether, manufactured by Tohto Kasei Co., Ltd.), ED-502, 503, 509 (Adeka glycidol, manufactured by ADEKA), YED-122 (alkyl phenol monoglycidyl ether, manufactured by Mitsubishi Chemical Corporation) ), KBM-403 (3-glycidoxypropyltrimethoxysilane), LS-7970 (1,3-bis (3′-glycidyloxypropyl) -1,1,3,3-tetramethyldisiloxane) (Shin-Etsu) Chemical Industry Co., Ltd.), TSL-8350 (γ-glycidoxypropyltrimethoxysilane), TSL-8355 (γ-glycidoxypropylmethyldimethoxysilane), TSL-9905 (γ-glycidoxypropylpentamethoxydisiloxane) (Toshiba Silicone Corporation) And a known compound of a reactive diluent having 1 to 2 epoxy groups in one molecule.

  The prepreg used in the present invention can be obtained, for example, by impregnating a substrate with a resin varnish obtained by blending a thermosetting resin composition and an organic solvent, and drying. Although it does not specifically limit as a base material used here, Generally fiber base materials, such as a woven fabric and a nonwoven fabric, are used. Examples of the fiber substrate include inorganic fibers such as glass, alumina, boron, silica alumina glass, silica glass, tyrano, silicon carbide, silicon nitride, zirconia, aramid, polyether ether ketone, polyether imide, polyether sulfone. Further, there are organic fibers such as cellulose and mixed papers thereof, and glass fiber woven fabrics and nonwoven fabrics are particularly preferably used. The thickness of the substrate may be appropriately selected according to the desired thickness of the prepreg or laminate, and is not particularly limited, but is preferably 0.01 to 0.4 mm, more preferably 0.02 to 0.00. A 3 mm one is used. The drying conditions for producing the prepreg are not particularly limited, but can be freely selected according to the desired prepreg characteristics within a drying temperature of 60 to 200 ° C. and a drying time of 1 to 30 minutes. Moreover, the ratio of the impregnating resin composition in the substrate is not particularly limited, but is preferably 30 to 90% by mass, and more preferably 40 to 80% by mass.

The prepreg with a resin film of the present invention is formed by arranging a resin film containing a fluorine atom on both surfaces or at least one surface of the prepreg.
Therefore, the resin film may be directly attached to the surface of the prepreg, or may be disposed on the surface of the prepreg via another film or the like.
In addition, although it does not specifically limit as a method of sticking a resin film directly on the surface of a prepreg, For example, the laminating method, the press method, etc. are mentioned.
The resin film used in the present invention contains fluorine atoms, and as a method for bonding the resin film and the prepreg, a laminating method is preferable, and it is effective for reducing the tackiness of a resin composition of a prepreg having a lot of tackiness.
As a method of laminating a resin film containing fluorine atoms and a prill leg, a resin film is formed by placing a film formed of a fluororesin on one side or both sides of a dried prepreg impregnated in a glass cloth with a thermosetting resin composition. There is a method of heating to a temperature equal to or higher than the softening point of the fluororesin or a temperature equal to or higher than the softening point of the thermosetting resin composition of the prepreg and laminating with a roll or the like, and a prepreg having a fluororesin layer (prepreg with a resin film) Can be produced. The conditions for laminating with a roll are, for example, a pressure of 0.5 to 10 MPa, a temperature of 50 to 180 ° C., and a roll speed of 0.5 to 4 m / min.
Although the thickness of the resin film containing a fluorine atom is not limited, 0.1-50 micrometers is preferable as a single-sided thickness, 1-18 micrometers is more preferable, and 2-15 micrometers is still more preferable.

  The metal-clad laminate of the present invention is a single layer or a laminate of two or more prepregs with a fluorine atom-containing resin film of the present invention according to the desired thickness of the laminate, and the metal is laminated on one or both sides. It can be manufactured by overlapping foils and heating and pressing. As the metal foil to be used, copper foil or aluminum foil is mainly used, but other metal foil may be used. The thickness of the metal foil is usually 2 to 200 μm. The heating and pressurization may be performed by a general method, for example, using a multistage press, a multistage vacuum press, continuous molding, or an autoclave molding machine, preferably at a temperature of 130 to 230 ° C. and a pressure of 0.5 to 10 MPa. More preferably, it is heated and pressurized for 0.1 to 5 hours under the conditions of a temperature of 160 to 210 ° C. and a pressure of 1 to 4 MPa. These conditions are desirably determined appropriately depending on the prepreg characteristics, the reactivity of the thermosetting resin used, the ability of the press, the thickness of the target laminate, and the like. In addition, as for the molding temperature, when a fluororesin is used as a resin film containing a fluorine atom, when its softening point or melting point is high, it is heated only for a short time at a temperature higher than the above temperature, and the resin films or resin films And metal foil can be set to be bonded.

  The printed wiring board of the present invention can be obtained by processing the metal foil-clad laminate of the present invention by a known method in a printed wiring board manufacturing method such as a subtracting method or drilling. A multilayer wiring board can also be obtained by appropriately laminating and processing the prepreg of the present invention, a metal-clad laminate, and a printed wiring board.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to this.

<Adjustment of varnish>
Example 1
30 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name YDCN-700), 70 parts by mass of a tetrabromobisphenol A type epoxy resin (manufactured by Toto Kasei Co., Ltd., trade name YDB-400), 4 parts by mass of dicyandiamide Parts, pulverized silica (average particle size 5 μm, water content 0.06% by mass) 45 parts by mass, 1-cyanoethyl-2-methylimidazole 0.4 parts by mass, mixed solvent (by mass ratio) of methyl ethyl ketone and ethylene glycol monomethyl ether 1: 1) to obtain a varnish having a nonvolatile content of 70% by mass.

(Example 2)
30 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name YDCN-700), 70 parts by mass of a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name Epicoat 828), tetra which is a flame retardant Bromobisphenol A (manufactured by DEAD SEA-Bromine) 58 parts by mass, phenol novolac resin (manufactured by DIC, trade name Phenolite TD-2106) 32 parts by mass, spherical silica (average particle size 0.7 μm, water content 0. 02 parts by mass) 98 parts by mass and 0.5 parts by mass of phenylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and propylene glycol monomethyl ether (2: 1 by mass ratio) to obtain a varnish having a nonvolatile content of 70% by mass.

(Example 3)
30 parts by mass of phenol novolac type epoxy resin (manufactured by DIC Corporation, trade name N-740), 70 parts by mass of cresol novolac type epoxy resin (trade name YDCN-703, manufactured by Toto Kasei Co., Ltd.), tetrabromobisphenol A type epoxy resin 65 parts by mass (product name: Epicron 153, manufactured by DIC Corporation), 75 parts by mass of bisphenol A novolac resin (product name: VH-4150, manufactured by DIC Corporation), pulverized silica (average particle size: 5 μm, moisture content: 0.06% by mass) ) 60 parts by mass and 0.8 parts by mass of undecylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and propylene glycol monomethyl ether (2: 1 by mass ratio) to obtain a varnish having a nonvolatile content of 70% by mass.

<Preparation of prepreg>
Each of the varnishes of Examples 1 to 3 was impregnated into a 100 μm-thick glass woven fabric (IPC product number 2116 type) and dried in a drier at 150 ° C. for 4 minutes, respectively. A prepreg was obtained.

<Preparation of resin film containing fluorine atoms>
A PET (polyethylene terephthalate) film having a thickness of 50 μm, a FEVE alternating copolymer (fluoroethylene / vinyl ether alternating copolymer) as a Lumiflon (Asahi Glass Co., Ltd.) 5 mass% methyl ethyl ketone solution, and isophorone diisocyanate in a solid content of 5%. The solution mixed so that it might become mass% was apply | coated, and it heated at 60-75 degreeC repeatedly, and obtained the resin film of FEVE of thickness about 5 micrometers.

<Resin film lamination>
The FEVE resin film obtained above was laminated on both surfaces of the prepreg surface obtained above by roll lamination (at the time of roll lamination, the PET film was laminated at the same time, and at the time of use, the PET film was peeled off to remove the prepreg with FEVE. use). The roll laminating conditions are a pressure of 2 MPa, a temperature of 160 ° C., and a roll speed of 2 m / min.
These were designated as Examples 1 to 3, respectively. Moreover, the prepreg which does not laminate the FEVE resin film obtained above was made into Comparative Examples 1-3, respectively.

<Production of metal-clad laminate>
Each prepreg with FEVE (Examples 1 to 3) obtained above and each prepreg (Comparative Examples 1 to 3) not laminated with a resin film are stacked 8 by 8 respectively, and a copper foil having a thickness of 18 μm is formed on both surfaces. The prepregs of Examples 1 to 3 and Comparative Examples 1 to 3 were heated and pressurized at a pressure of 3.5 MPa and a temperature of 180 ° C. for 90 minutes to obtain a double-sided copper-clad laminate.

<Evaluation>
The copper foil of each double-sided copper-clad laminate produced as described above was removed by etching, and moisture-absorbing solder heat resistance and water absorption were evaluated.

  The moisture absorption solder heat resistance of the substrate is that of a substrate immersed in a solder bath at 288 ° C. for 20 seconds after heating, pressurizing and moisture absorption treatment (PCT treatment) for a predetermined time in a pressurized chamber of 121 ° C. and 100% RH. Evaluation was made by observing the appearance.

  The water absorption was evaluated by measuring the mass before and after treatment of a substrate heated, pressurized and moisture-absorbed (PCT treated) for a predetermined time in a pressurized chamber at 121 ° C. and 100% RH. That is, the difference in mass of the substrate before and after heating was divided by the mass of the substrate before heating, and expressed as 100 minutes.

  The above evaluation results are shown in Table 1. In addition, each evaluation code | symbol of moisture absorption solder heat resistance of a board | substrate means (circle): No change, (triangle | delta): Generation | occurrence | production of a mess ring, *: Generation | occurrence | production of blistering, and three symbols are the results evaluated by three test pieces. In Table 1, for example, “PCT-3h” represents that the PCT process was performed for 3 hours.

（吸水率；質量％）

(Water absorption rate: mass%)

  From Table 1, it has confirmed that the laminated board of Examples 1-3 was low in water absorption compared with the comparative example, was excellent in moisture absorption solder heat resistance, and heat resistance.

Claims (5)

  A prepreg with a resin film in which a resin film containing a fluorine atom is disposed on both surfaces or at least one surface of a prepreg obtained by impregnating a glass cloth with a thermosetting resin composition and drying.   The prepreg with a resin film according to claim 1, wherein the thermosetting resin composition contains an epoxy resin.   The prepreg with a resin film according to claim 1 or 2, wherein the resin film containing a fluorine atom is a film of a tetrafluoroethylene / hexafluoropropylene copolymer (FEP) or a fluoroethylene / vinyl ether alternating copolymer.   The prepreg with a resin film according to any one of claims 1 to 3 is a single layer, or two or more layers are laminated, and a metal foil is disposed on one side or both sides thereof, and heated and pressurized. Metal-clad laminate.   A printed wiring board obtained by forming wiring using the metal-clad laminate according to claim 4.