JP2000077803A - Organic fiber reinforced printed wiring board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light weight and thin film organic fiber reinforced printed wiring board without using an epoxy resin impregnated prepreg on the conventional glass fiber cloth, and to provide the manufacturing method of the board which can be formed efficiently at a high yield. SOLUTION: This printed wiring board consists of metal foil sheets 1, the thermosetting resin 2 coating one surface of the metal foil sheet, and the woven or non-woven fabric reinforcement material 3 coating the other surface of the metal foil as shown in the figure (a). The reinforcement material 3 is pinched by the resin 2, the metal foil sheet 1 is adhered by molding under pressure and heat by positioning them outside, and an organic fiber reinforced double-side substrate 8 is formed as shown in the figure (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a portable communication device,
The present invention relates to a small, lightweight, thin organic fiber reinforced printed wiring board used for communication electronic equipment such as a PDA (mobile terminal) and a mobile PC, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, demands for ultra-light, compact and high-performance mobile communication devices such as mobile phones and band-held PCs have been increasing, and printed circuit boards used for these devices have high density such as MCM substrates. Technology development corresponding to implementation is required. In other words, as the number of pins of the IC chip increases, the pitch gap becomes narrower, and as the mounting of the bearer chip increases, in particular, the lines and spaces become finer.
In addition, there is a demand for a reduction in the board area by interlayer connection using small-diameter vias instead of through holes. However, with the downsizing and thinning of the board, the thickness of the interlayer insulating layer has been reduced to three-dimensionally. In addition to increasing the wiring density, it is necessary to minimize variations in the thickness of the substrate from the viewpoint of characteristic impedance management. In such a high-density substrate,
The connection between the outer layers BVH and IVH is mainly performed.
2 mm diameter drilling is difficult with a mechanical drill, and often uses a carbon dioxide laser. Furthermore, since the prepreg using glass fiber as the reinforcing material does not have good laser workability, the substrate material is also required to have good laser workability.

[0003] In order to cope with such a problem, it is difficult to cope with a conventionally used printed wiring board based on a laminated structure of a prepreg obtained by impregnating a glass cloth for reinforcement with an epoxy resin or the like and a copper foil. Is coming. That is, in order to make the printed wiring board thin and lightweight, and to form a fine circuit wiring pattern, at least 0.
A pre-leg with a thickness of about 1 mm is required, but at such a thickness, the embossing of the texture structure of the reinforced glass cloth becomes a major problem. Also, from the viewpoint of reducing the weight of the substrate,
The weight of the glass fiber itself is also an obstacle in a microminiature and lightweight wiring board.

[0004] In order to address the above problems, there is a method of replacing the reinforced glass fiber itself with a light-weight organic fiber, particularly a high-performance organic fiber which is superior in density to electrical properties such as mechanical strength, heat resistance and insulating properties and is more advantageous than glass. It is being proposed. For example, para-aramid fiber and meta-aramid pulp (Japanese Unexamined Patent Publication No.
JP-A-228289), or a molten liquid crystalline aromatic polyester fiber and its pulp (JP-A-9-217298).
Japanese Patent Application Laid-Open Publication No. HEI 9-222) has proposed a method of using an organic fiber reinforced pre-leg in which a matrix resin is impregnated in a papermaking sheet. Further, as a disclosure example applicable as a basic technology of the organic fiber reinforced substrate, a dry sheet in which a mixed web composed of thermoplastic fibers such as aramid fibers and polyester is integrated with a thermal calender is impregnated with epoxy resin to form a flexible substrate. A method has been proposed (US Pat. No. 3,855,047, 1974).

[0005]

However, the above-mentioned conventional techniques for manufacturing a printed wiring board using a resin-containing organic fiber reinforced pre-leg material have the following problems. The conventional technology is based on a basic technical concept of laminating a reinforced organic fiber impregnated with an epoxy resin or the like and then forming a prepreg. However, resin impregnation conditions for forming the prepreg (for example, , Resin liquid concentration, viscosity, impression temperature, etc.) greatly affects the uniformity of dispersion, microvoids, and thickness of the resin in the prepreg.
It is difficult to control the drying process and the like, and there is a problem in the production yield and quality that occur particularly in the production of a thin prepreg of 0.1 mm or less. When the lamination of such a thin organic fiber prepreg is premised, the thickness uniformity and the surface smoothness of the insulating resin layer are hardly obtained due to uneven flow of the resin. Manufacturing was problematic. Further, as a concept close to the concept of forming a high-density substrate without using a resin-impregnated prepreg, there is a method of manufacturing a build-up substrate in which an insulating resin layer and a conductive wiring layer are sequentially laminated to form a high-density multilayer substrate (particularly, JP-A-7-330867). However, this manufacturing method is a method in which an insulating resin is screen-printed or curtain-coated on a core substrate, and then a copper foil alone is laminated and laminated. There is a problem related to resin application such as resin adhesiveness. After applying a light or thermosetting insulating resin layer to the core circuit surface and performing light or heat curing treatment, buff polishing for flattening the surface of the insulating layer and further plating up However, there is a problem that it is necessary to perform a surface roughening treatment. In addition, there are problems in handling thin copper foil and problems in working environment such as vaporization of a solvent at the time of resin application. In addition, the core substrate is made of an insulating base material such as ordinary glass cloth or glass non-woven fabric, and basically uses glass fiber, so it can be used to reduce the weight of the substrate, make it smaller and thinner, and lower its dielectric constant. Had a problem that there was a limit. Further, there is a problem that it is difficult to further reduce the cost of the high-density printed wiring board and to realize the improvement of the direct yield of 98% or more without the related repeller.

An object of the present invention is to provide a lightweight and thin printed circuit board reinforced with organic fibers without using a conventional prepreg in which a glass fiber cloth is impregnated with an epoxy resin, and to provide an efficient production method with a good yield. It is to be.

[0007]

In order to achieve the above object, the organic fiber reinforced printed circuit board according to the present invention is characterized in that the organic fiber reinforced printed wiring board according to claim 1 uses a reinforcing material made of a woven or knitted fabric or a nonwoven fabric of organic reinforced fibers. The printed wiring board according to claim 1, wherein a metal foil with resin is disposed on both surfaces of a woven or knitted fabric or nonwoven fabric of organic reinforcing fibers that have not been subjected to a resin impregnation treatment to form a composite laminate, and the composite laminate is added. By forming the double-sided printed wiring board by pressure heating, the board can be molded at once without using the fiber-reinforced prepreg by resin impregnation, which is conventionally used, and the manufacturing of the printed wiring board with high precision It can be performed with good yield.
In Claim 2, after forming a double-sided printed wiring board, forming a circuit for an inner layer on the double-sided printed wiring board to form a core board, laminating a metal foil with resin on one or both sides of the core board, and performing heat and pressure molding Further, by repeating the steps of forming the conductor and laminating the resin-attached metal foil to form a multilayer printed wiring board, it is possible to provide a lightweight, compact, high-performance, high-density printed wiring board. In claim 3, by using a copper foil as the metal foil, an inexpensive and reliable printed wiring board can be obtained. In claim 4, a plain woven fabric in which the organic reinforcing fibers are not impregnated with a resin can be used.
In claim 5, the plain woven fabric can be formed from aramid or liquid crystalline aromatic polyester fiber, or a composite fiber thereof. 7. The method for producing a lightweight and thin printed wiring board according to claim 6, wherein the reinforcing member is made of a woven or knitted fabric of an organic reinforcing fiber or a nonwoven fabric, wherein the metal foil with resin is not subjected to a resin impregnation treatment. Forming a double-sided printed circuit board by forming a composite laminate by arranging reinforcing fibers on both sides of a woven or nonwoven fabric or a non-woven fabric, and pressing and heating the composite laminate to form a printed circuit board at a stroke Wiring boards can be manufactured with high accuracy and high yield. 8. The method according to claim 7, wherein after forming the double-sided printed wiring board, a circuit for an inner layer is formed as a core board, a metal foil with a resin is laminated on one or both sides of the core board, and heated and pressed, and then a conductor is formed. Forming a multilayer printed wiring board by repeating the process of laminating a metal foil with resin, eliminating the need for flattening and roughening the resin surface, and greatly simplifying the process of stacking the insulating layer and the circuit layer. Can be.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B illustrate an example in which the method described in claim 1 is applied to the manufacture of a double-sided substrate.
-D illustrate examples in which the method described in claim 2 is applied to a build-up multilayer substrate.

In FIG. 1, "a" indicates individual materials before lamination, and a woven or knitted fabric made of metal foils 1, 1 and a resin applied to one surface thereof, particularly a thermosetting resin 2, 2, and an organic reinforcing fiber. Or, as shown in b, the reinforcing material 3 is sandwiched between the resins 2 and 2, and the metal foils 1 and 1 are positioned outside and pressurized and heated and bonded to form the organic fiber, as shown in b. A reinforced double-sided substrate A is formed.

In FIG. 2, an organic fiber reinforced double-sided substrate A manufactured by the manufacturing method shown in FIG. 1 is used as a core substrate {see FIG. A conductive metal plating 4 is applied to form an inner layer circuit, and the hole is filled with a filling resin 6 (see b). The plated organic fiber reinforced double-sided substrate (core substrate) A is subjected to an etching pattern forming process to remove unnecessary portions to form an etching pattern-formed core substrate 7 (see c). On one side)
The resin-attached metal foil 8 to which the resin 10 is adhered is superimposed and molded at once by pressure and heat.

Thereafter, a resin-coated metal foil to which the resin 9 is adhered is overlaid and pressed and heat-formed, a hole is formed at a predetermined position, and a conductive outer-layer metal plating 11 is applied to form an outer-layer circuit. After that, the resin-attached metal foil 12 to which the resin is adhered is overlaid, pressed and heated, applied with a solder resist, and subjected to outer layer processing (see d) to form a multilayer board.

The metal foil (1, 1 in FIG. 1 and 1, 8 in FIG. 2) is not particularly limited as long as it is used for a printed wiring board. is there. In addition, the copper foil has at least one surface roughened, thereby improving the peel strength between the copper foil and the resin. The thickness of the copper foil is preferably 35 μm or less, and more preferably 18 μm or less, from the viewpoint of forming a fine pattern, the thinner the better.

The resin applied to the metal foil (see FIGS. 1, 2 and 2)
As 10), it is desirable to use a thermosetting resin particularly from the viewpoint of heat resistance of the printed circuit board.
Stage) thermosetting polymers are preferred. Examples of the thermosetting resin include epoxy, unsaturated acid polyester, polyimide, bismaleimide triazine (BT resin), phenol, and thermosetting polyphenylene ether (Journal of Circuit Packaging Society, 10 [3], p153-1260, 1995).
However, epoxy resin is often used in terms of balance between cost and performance, and know-how in handling in the manufacturing process, and ease of handling.

The epoxy may be one having an average of two or more functional groups per molecule. Bisphenol A type epoxy, bisphenol F type epoxy, bisphenol S type epoxy, polyfunctional epoxy such as phenol nopolak epoxy, cresol nopolak Epoxy, aromatic glycidyl ether, aromatic amine type, alicyclic type epoxy, and flame-retardant halogens thereof, especially brominated modified products, are mentioned as examples. Furthermore, the above-mentioned epoxy mixed composite resin is also included in the epoxy resin of the present invention.

[0015] The epoxy resin may be a curing agent, an acid anhydride curing agent, or a curing agent which is added depending on the epoxy equivalent used, such as amines such as dicyandiamide, diaminophenylmethane, and diaminodiphenylsulfone, and amine adducts. In addition to the accelerators, nitrile rubber modifiers for toughening, inorganic filler fine particles such as mica, calcium carbonate, barium sulfate for surface roughness improvement, molding aids for defoamers, leveling agents, etc. Agents and the like may be included. In addition, a known flame retardant, aluminum hydroxide, antimony trioxide, and an organic halide may be contained in the epoxy resin.

In order to further improve the affinity of the resin with the organic fiber layer, a so-called undercoat agent (for example, a low molecular weight epoxy, a reactive epoxy diluent,
It is preferable to apply, for example, methyl ethyl ketone or dimethylformamide), an epoxy solvent or the like in advance. Here, as the reactive epoxy diluent, monofunctional epoxy, tertiary carboxylic acid glycidyl ester, and Kajura E manufactured by Yuka Shell Co., Ltd.
Etc.

As disclosed in JP-A-9-232763, the resin applied to the metal foil may be formed of a plurality of resin layers. For example, after a base resin layer is applied and dried on a metal foil in advance, a surface resin is applied, and tackiness is imparted by adjusting drying conditions to improve resin affinity at the time of lamination with the organic fiber reinforcing layer.

When a thermoplastic polymer is selected as the resin, the resin is first applied to the surface of a metal foil in a molten state or in a solution form dissolved in a solvent, and then cooled to form a solidified film. At that time, by adjusting the cooling rate or the drying rate, if the polymer is a crystalline polymer, it becomes an amorphous state, and the resin is easily melted again by heating under pressure during lamination. Examples of the thermoplastic polymer include polyethylene terephthalate, polybutylene terephthalate, polyarylate (aromatic polyester, for example, Unitika U-polymer from bisphenol A and mixed acid chloride component), melt liquid crystalline polyester (for example, polyethylene terephthalate and hydroxy Polyester resin such as benzoate component copolymer, Unitika's rod run), polyamide resin such as polycarbonate, nylon 6, nylon 66, polyphenylene sulfide resin, polyacetal resin,
Fluororesins such as thermoplastic polyamides (polyenalimide, etc.) polyethylene tetrafluoride, polyphenylene ether (PPE), polyether ether ketone (P
EEK) resin.

The organic reinforcing fibers used in the reinforcing material in the form of a woven or knitted fabric or a non-woven fabric made of organic reinforcing fibers (3 in FIGS. 1 and 2) may be selected from the following fibers. A group of general-purpose industrial fibers, for example, polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, nylon 6, nylon 6
6, polyamide fibers such as nylon 46, polypropylene fibers, polyacrylonitrile fibers, and polyacetal fibers.

Also, a group of high-performance fibers having excellent high elasticity, high strength, heat and chemical resistance, such as polyvinyl alcohol fiber (for example, Kuraray KII) and high molecular weight polyethylene fiber (for example, Dyneema, Toyobo Co., Ltd.) ,
Polyacrylonitrile gel fiber, polyphenylene sulfide fiber, para-aramid (for example, liquid crystal anisotropic liquid-crystalline aramid), polyphenylene terephthalamide (for example, DuPont Kevlar, Akzo Twaron), and polyphenylene terephthalamide. Solution optically isotropic paraamide (for example, Teijin Technora) in which copolymerization component 3,4 diaminodiphenyl ether is added to diamine component, meta-aramid (for example, polymetaphenylene terephthalamide (for example, DuPont Nomex, Teijin Co., Ltd.) Mex)], liquid crystalline aromatic polyester fibers (for example, those polymerized from hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, Kuraray Vectran),
There are polyimide fibers (for example, P89, Lenting Corporation) and polyetheretherketone (PEEK) fibers. Furthermore, high performance polybenzoazole fibers containing heterocycles [for example, polyparaphenylene azole (PBZ)
T)] and liquid crystalline aromatic polyester fibers (for example, Kuraray Vectran).

When the substrate becomes thinner, the deformation amount of the beam increases in one column. The known expression for calculating the deformation amount of the beam is applied to a rectangular section plate to derive the following expression. δ = P / (4E × W) × (L / T) ³ ..., where δ: Deflection amount of the doubly supported beam at one point concentrated load P: One point concentrated load E: Tensile elastic modulus of material W: Substrate Width L: substrate length T: substrate thickness

As is apparent from the above equation, the amount of deflection δ of the substrate increases in inverse proportion to the cube of the thickness T of the substrate (for example, when the thickness T of the substrate becomes １ ／, the amount of deflection under the same load becomes (8 times), the thinning of the substrate may cause a problem in shape stability such as warpage of the substrate in the mounting process of the substrate. In order to prevent this by selecting a material and preventing it by the strength of the material, From the equation, the tensile modulus E of the material (reinforcement)
Needs to be increased corresponding to the reduction in the substrate thickness.

From the above, among the above-mentioned various fiber groups, particularly preferable ones are the above-mentioned high-performance fiber groups. Among them, para-aramid fibers or liquid crystalline aromatic polyester fibers (for example, Vectran) are suitable. I have. In addition, in addition to using the above-mentioned fiber group individually, those mixed with each other, that is, those obtained by forming and blending in a solution or melt state in a spinning stage into a fiber,
Alternatively, as viewed from the cross section of the spinning nozzle, different types of polymers may be used as a parallel conjugate or core-sheath conjugated fiber, or a conjugated fiber obtained by twisting individual fibers after fibrillation may be used.

As the woven or knitted fabric, a continuous yarn composed of continuous filaments or spun yarn is woven by a loom, and a warp and a weft are formed into a basic woven fabric, a plain woven fabric, a twill woven fabric, a satin woven fabric, and a modified woven fabric of these structures, or a warp yarn. A cross-woven fabric in which the weft is another type of fiber can also be used. Further, a knitted fabric in which yarn loops are continuously formed in a longitudinal (warp) direction (course) and a weft direction (weld) by a warp knitting machine or a weft knitting machine may be used. Less plain woven fabric is suitable.

The basis weight of the plain woven fabric is 10 to 5
00 g / m ² is preferable in view of the weight and thickness of the printed wiring board and the affinity with the resin at the time of lamination, and particularly preferably 20 to 10
0 g / m ² is desirable. In the design of the woven fabric, the woven density and fineness (thickness) may be adjusted in consideration of the form stability during the woven process so as to satisfy the above-mentioned basis weight range. Both 20-60 lines / 25mm,
The yarn configuration is preferably a single yarn denier, in which 10 to 200 filaments of 1 to 5 deniers are bundled, and the total fineness is 10 to 1000 deniers.

The plain woven fabric is preferably a finely woven fabric from which weaving oil, sizing (glue) and the like have been removed, and in order to increase the affinity with the resin applied to the metal foil, Also suitable are those obtained by applying a dry method using a corona or a plasma, a wet method using a surface treating agent such as an epoxy type, or a surface treatment using a combination of these methods to the above-mentioned scoured plain woven fabric.

The non-woven fabric is a fabric (web) having a shape-retaining property by entanglement of fibers without using the above-mentioned weaving and knitting, and staple cotton from the above-mentioned fiber group is carded with a card, and needled. Short-fiber nonwoven fabric in which fibers are physically entangled by a punch or a high-pressure water stream (spunlace), or a continuous fiber sheet made of continuous filaments by a direct spinning method in which a solution or a molten fiber is combined with a high-pressure air flow inside or outside a nozzle. Spunbonded long-fiber nonwoven fabrics, and wet-laid nonwoven fabrics by chopping strand fibers by papermaking. In general, nonwoven fabrics do not go through weaving and knitting, and at the same time, the cost is low, and since the sheet is flexible, it has a shape-imparting property as a flexible material, and can be used as an organic reinforcing fiber layer depending on the application. .

The resin-attached metal foil and the organic reinforcing fiber sheet press and heat to permeate the resin into the organic reinforcing fiber layer, and are also cured or cooled and integrated. A vacuum laminating press such as a hot plate press press method and an autocrepe method is suitable. The stack of metal (copper) foil with resin and organic reinforcing fiber layer is 10 Torr to less than 20 Torr in order to remove the temperature, pressure, time and the air, product gas and moisture contained in the fiber layer during heating under pressure. It is desirable that the degree of vacuum is as follows.

FIG. 2D shows that after using the organic fiber reinforced double-sided substrate A shown in FIG. 1B to form a circuit on the surface metal foil 1 of the substrate A, the double-sided substrate A is used as the core substrate 7 and the resin-attached metal foil 8 is used. 2 shows a multilayer substrate formed by laminating circuits on both surfaces of a core substrate 7. The insulating resin layer 2 is applied to the metal foil 1 in advance and is integrated, so that the resin surface is not required to be flattened or roughened, and the step of stacking the insulating layer and the circuit layer can be greatly simplified. it can. By repeating the lamination of the resin-attached metal foil, the via processing, and the circuit formation on the metal foil on the four-layer substrate shown in FIG. 2D, the present invention can be applied to the production of a multilayer substrate having more than four layers.

[0030]

EXAMPLES Experimental results of Examples and Comparative Examples will be described below. The experimental conditions are as follows. 1) Adhesion strength of copper foil According to JIS C5012 8.1. 2) Laser beer workability Microsection observation is performed using a carbon dioxide laser machine under the following conditions. Pulse width: 0.1 to 5 μS Number of shots: 10 shots Laser frequency: 150 Hz Irradiation method: Continuous irradiation Scan method: Galvano method 3) Solder heat resistance After floating in a solder bath at 250 ° C. for 30 seconds according to JIS C5012, The blister is visually observed. 4) Through-hole plating properties According to JIS C5014, holes are drilled by mechanical drilling, and through-hole copper plating is applied to an average thickness of 20 μm, and the surroundings of the plating are observed by a microsection. 5) Sheet thickness 0.01 micrometer according to JIS C5014
Measure to mm.

Example 1 After cutting a Vectran fiber plain woven cloth (Vectran cloth, manufactured by Kuraray Co., Ltd.),
A copper foil with a semi-cured resin obtained by applying an epoxy resin to a thickness of 18 μm on a copper foil of 18 μm thickness (APL, manufactured by Sumitomo Bakelite Co., Ltd.)
-4001) was placed on the Vectran surface and vacuum laminated, and 5
A double-sided copper-clad board for evaluation of 0 cm square was prepared. 1) Vectran cloth specifications Yarn: 100 denier / 20 yarns Weight: 52 g / m ² Weaving density: Warp: 60 yarns / 25 mm, weft yarn: 60 yarns / 25 mm Treatment: Finished untreated surface 2) Lamination conditions Temperature: After the temperature is raised from 80 ° C to 140 ° C at 3 ° C / min, the temperature is raised to 170 ° C and maintained for 65 minutes. Pressure: maintained at 30 kg / cm ² Vacuum degree: 10 torr

[Comparative Example 1] Using aramid fiber plain woven cloth (Teijin Techno Lacross M0200E), FR-
4 After impregnating and drying with an epoxy MEK solution varnish to prepare an epoxy-impregnated prepreg having a resin content of 70%, a copper foil having a thickness of 18 μm and having one surface roughened was arranged such that the roughened surface was on the prepreg side. The laminate was laminated under the same conditions as in Example 1 to prepare a 50 cm square double-sided copper-clad substrate for evaluation. Specifications of Aramid Cloth Yarn: Denier 200 (133 filaments), non-twisted Weight: 61 g / m ² Woven density: 34 warps / 25.4 mm, 34 wefts / 25.4 mm Treatment: Epoxy surface treated product

Comparative Example 2 An epoxy-impregnated prepreg was prepared in the same manner as in Comparative Example 1 using a plain weave cloth of PPS fiber (Procon Cloth manufactured by Toyobo Co., Ltd .: LPR9110G).
A 50 cm square double-sided copper-clad substrate for evaluation was prepared. Specifications of PPS cloth Yarn: Denier 225 (60 filaments) Weight: 68 g / m ² Weave density: 34 warps / 25.4 mm, 34 wefts / 25.4 mm

(Table 1: Comparison of adhesion strength of substrate copper foil) Item Example 1 Comparative example 1 Comparative example 2 Maximum value 1.83 1.13 0.63 Minimum value 1.75 0.98 0.31 Range 0.08 0.15 0.32 Average 1.79 1.04 0.42 Standard deviation 0.03 0.05 0.11 Variability (percent) 1.67 4.81 26.19 Note) Adhesion force unit: kgf / cm Range = (maximum value) − (minimum value) Fluctuation rate = (standard deviation) / (average value) × 100

(Table 2: Comparison of Substrate Processing Performance) Item Example 1 Comparative Example 1 Comparative Example 2 Laser workability OK OK Good Solder heat resistance OK OK Not OK swell Through hole plating OK OK OK Plate thickness average (mm) 0.24 0.25 0.19 Thickness standard deviation 0.002 0.016 0.004 Thickness variation rate (percent) 0.81 6.40 2.10 Note) Thickness variation rate = (second deviation) / (plate) Thickness average value) x 100

As is clear from Tables 1 and 2, Example 1 of the present invention did not have any special fiber surface treatment as compared with Comparative Examples 1 and 2 using the conventional resin-impregnated fiber reinforced prepreg. Regardless, the epoxy resin can be filled between the fibers, the peel strength of the outer copper foil is stable and high, and the fluctuation of the substrate thickness is small. A fiber reinforced printed circuit board can be manufactured.

[0037]

Since the present invention is configured as described above, it has the following effects. A lightweight and thin printed wiring board using a reinforcing material made of a woven or knitted fabric of an organic reinforcing fiber or a nonwoven fabric, wherein a metal foil with a resin is woven or knitted or a nonwoven fabric of an organic reinforcing fiber not subjected to a resin impregnation treatment. To form a composite laminate by disposing on both sides of
By pressing and heating the composite laminate to form a double-sided printed circuit board, the substrate can be molded at once without using a conventionally used fiber-reinforced prepreg impregnated with a resin, and a printed circuit board can be formed. The substrate can be manufactured with high accuracy and high yield. After forming a double-sided printed wiring board, forming an inner layer circuit on the double-sided printed wiring board to form a core board, laminating a metal foil with resin on one or both sides of the core board, heating and pressing, and further forming a conductor. By repeating the step of stacking the resin-attached metal foil to form a multilayer printed wiring board, it is possible to provide a lightweight, compact, high-performance, high-density printed wiring board. By using a copper foil as the metal foil, an inexpensive and reliable printed wiring board can be obtained. A method for manufacturing a lightweight and thin-walled printed wiring board using a reinforcing material made of a woven or knitted fabric of organic reinforcing fibers or a nonwoven fabric, wherein a metal foil with resin is woven or knitted with organic reinforcing fibers not subjected to a resin impregnation treatment. By forming a composite laminate by arranging it on both sides of a cloth or a non-woven fabric, and forming a double-sided printed wiring board by applying pressure and heating to the composite laminate, the substrate can be molded at once and the production of a printed wiring board can be performed. High precision and good yield can be achieved. After forming a double-sided printed wiring board, an inner layer circuit is formed to form a core substrate, a metal foil with resin is laminated on one or both surfaces of the core substrate, heated and pressed, and then a conductor is formed and a metal foil with resin is formed. By forming a multilayer printed wiring board by repeating the step of stacking, the flattening and roughening of the resin surface becomes unnecessary, and the step of stacking the insulating layer and the circuit layer can be greatly simplified.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a double-sided printed wiring board of the present invention.

FIG. 2 is an illustration of a method for processing an organic fiber reinforced printed wiring board of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 metal foil (copper foil), 2 resin, 3 organic reinforcing fiber (reinforcing material), 4 plating layer 5 inner layer via, 6 hole filling resin, 7 etching pattern forming core substrate 8 metal foil with resin, 9, 10 resin, 11 Outer layer metal plating 12 Metal foil with resin, A Organic fiber reinforced double-sided board

Claims (7)

[Claims] 1. A lightweight and thin printed wiring board using a reinforcing material made of a woven or knitted fabric or a nonwoven fabric of an organic reinforcing fiber, wherein a metal foil with a resin is coated with an organic reinforcing fiber not subjected to a resin impregnation treatment. An organic fiber reinforced printed wiring board, wherein a composite laminate is formed by disposing on both surfaces of a woven or knitted fabric or a nonwoven fabric, and the composite laminate is heated under pressure to form a double-sided printed wiring board. 2. The organic fiber reinforced printed wiring board according to claim 1, wherein a double-sided printed wiring board is formed, an inner layer circuit is formed on the double-sided printed wiring board to form a core board, and one or both sides of the core board are provided. An organic fiber reinforced printed wiring board, wherein a multi-layer printed wiring board is formed by repeating a process of forming a conductor and laminating a metal foil with a resin after laminating a metal foil with a resin, forming under heat and pressure. 3. The organic fiber reinforced printed circuit board according to claim 1, wherein the metal foil is a copper foil. 4. The organic fiber reinforced printed wiring board according to claim 3, wherein the organic reinforced fiber is a plain woven cloth not impregnated with a resin. 5. The organic fiber reinforced printed wiring board according to claim 4, wherein the plain woven fabric is formed of aramid, a liquid crystalline aromatic polyester fiber, or a composite fiber thereof. substrate. 6. A method for manufacturing a light-weight and thin printed wiring board using a reinforcing material made of a woven or knitted fabric or a non-woven fabric of organic reinforcing fibers, wherein a metal foil with a resin is not subjected to a resin impregnation treatment. An organic fiber reinforced printed wiring board characterized by forming a composite laminate by arranging on both sides of a woven or knitted fabric or nonwoven fabric of a reinforcing fiber, and forming a double-sided printed wiring board by heating the composite laminate under pressure. Production method. 7. The method for manufacturing an organic fiber reinforced printed circuit board according to claim 6, wherein after forming the double-sided printed circuit board, an inner layer circuit is formed to form a core board, and a resin is formed on one or both sides of the core board. A method for manufacturing an organic fiber reinforced printed wiring board, comprising forming a multilayer printed wiring board by repeating steps of forming a conductor and laminating a metal foil with a resin after heating and press-molding the coated metal foil. .