JPH03243334A - Laminate - Google Patents

Abstract

PURPOSE:To obtain the characteristics of high frequency, and make machinability excellent, and further restrain the thermal expansion in the direction of the plane by constituting the layer of a base material that consists of the layer of a glass fiber woven fabric and the layer of an aromatic polyamide fiber nonwoven fabric being laid over at least one surface thereof, and specifying the glass chemical composition. CONSTITUTION:This laminate is constituted such that the layer of a base material infiltrated with resin comprises the layer of a glass fiber woven fabric and the layer of an aromatic polyamide fiber nonwoven fabric being placed on at least one surface thereof. And, the glass chemical composition of the glass fiber woven fabric is allowed to be 50-75wt.% in SiO2, 15-35wt.% in Al2O3, 5-15wt.% in alkaline earth metallic oxide, and 5wt.% or below in alkaline metallic oxide. And, the thickness of layer of the aromatic polyamide fiber nonwoven fabric in its surface is preferably to be 100-400mum with respect to the thickness of layer of the glass fiber woven fabric. By making the laminate into a ratio of the component mentioned-above, it becomes possible to make the thermal expansion small, and also insure the machinability therefor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laminate having excellent high frequency characteristics and suitable for use in printed wiring boards.

2. Description of the Related Art Printed wiring boards used in electronic devices are required to have a lower dielectric constant as circuit densities become higher and signal frequencies handled become higher.

Usually, as a wiring board, a laminate is used, which is obtained by stacking a predetermined number of prepregs obtained by impregnating a sheet-like base material with a resin and drying them, and then molding them under heat and pressure. For example, glass fiber woven fabric is used as the base material for the core layer of the laminate, and aromatic polyamide fiber woven fabric is used as the base material for the surface layer of the laminate. A similar method has been proposed (Japanese Unexamined Patent Publication No. 125690/1983).

This technology has excellent high frequency characteristics because it uses a base material made of aromatic polyamide fiber for the surface layer that forms the circuit. In addition, aromatic polyamide fibers have a negative coefficient of linear expansion, so they suppress thermal expansion in the planar direction of the laminate and improve the solder connection reliability of components mounted on printed wiring boards using the surface mount method. But it's convenient.

Problems to be Solved by the Invention In the above technology, the glass fiber woven base material of the core layer is necessary to suppress thermal shrinkage of the laminate during the heating process during processing of the laminate into a printed wiring board. be. however,
The glass fiber has a large coefficient of linear expansion (5 to 6 Xl0
-'/ ``C) Although aromatic polyamide fibers with a small coefficient of linear expansion (-5,5X10-6/ ``C) are used in the surface layer, due to the influence of the glass fibers,
It is still not sufficient to suppress thermal expansion in the planar direction of the laminate.

It is conceivable to use quartz glass fibers with a small coefficient of linear expansion as the glass fibers, but since quartz glass is hard, machining of the laminate becomes extremely difficult.

An object of the present invention is to provide a laminate that has excellent high frequency characteristics, uses a glass fiber woven material for the core layer, has good machinability, and has further improved suppression of thermal expansion in the planar direction. .

Means for Solving the Problems The laminate according to the present invention has a base material layer impregnated with a resin,
It consists of a layer of glass fiber woven fabric and a layer of aromatic polyamide fiber nonwoven fabric overlaid on at least one surface thereof. and,
The glass chemical composition of the glass fiber woven fabric is as follows.

SiO2: 50-75% by weight A1□03: 15-35% by weight Alkaline earth metal oxide = 5-15% by weight Alkali metal oxide: 5% by weight or less Also, the thickness of the layer of aromatic polyamide fiber nonwoven fabric on the surface The thickness is preferably 10% relative to the thickness of the layer of glass fiber fabric.
It is 0 to 400 μm.

Function: It is possible to reduce the linear expansion coefficient of glass fiber woven fabric by increasing the proportion of SiO2 and AIz03 components, but the fibers themselves become hard and flexible, resulting in poor machinability of the laminate. .

Therefore, alkali metal oxides are blended as a glass component to ensure the machinability of the laminate. However, if the alkali metal oxide is included in a proportion exceeding 5% by weight to ensure this, the laminate Thermal expansion in the planar direction of the plate increases, and electrical insulation properties decrease when moisture is absorbed.

In the laminate according to the present invention, as the glass component of the glass fiber woven fabric, the content of alkali metal oxides is suppressed to 5% by weight or less to O, and alkaline earth metal oxides are contained, so that the above-mentioned By adjusting the component ratio, it is possible to reduce thermal expansion and ensure machinability.

If the component ratio of 5in2 is less than 50% by weight, the thermal expansion of the laminate cannot be sufficiently suppressed, and if it exceeds 75% by weight, machinability cannot be ensured even if alkaline earth metals are included. It disappears.

Regarding the AIZO3 component, it is not possible to sufficiently suppress the thermal expansion of the outer laminate if it is less than 5% by weight;
If it exceeds % by weight, machinability deteriorates.

Even if the alkaline earth metal oxide component is included to a certain extent, it has little effect on increasing the thermal expansion of the laminate, and by containing it at 5% by weight or more, it is possible to ensure the machinability of the laminate. ing. However, if the content exceeds 15% by weight, the thermal expansion of the laminate will increase, so the content should be 15% by weight or less.

Since the layer of aromatic polyamide fiber non-woven fabric is placed on the surface, the high-frequency properties are originally good, but by combining it with the glass fiber woven fabric of the above composition, the laminate becomes stronger than when it is combined with the conventional glass fiber woven fabric. The dielectric constant of is an even smaller value. In addition, aromatic polyamide fiber nonwoven fabric is
Compared to the case where such woven fabric is used, it is advantageous in that it has better adhesion with the glass fiber woven base material layer and does not cause peeling between the eyebrows when punching or drilling laminates. There is.

EXAMPLE When producing a laminate according to the present invention, the glass fiber woven fabric should be degreased by heat cleaning to improve its adhesion to the resin. Usually, a material woven from glass thread made of about 200 single fibers with a diameter of 5 to 9 μm is used. Aromatic boria saturated fiber nonwoven fabrics are preferably made by dispersing the fibers in water, making paper using fourdrinier, and binding them with acrylic resin, epoxy resin, cellulose fiber, etc., as they have uniform weight. Although it is better, it may also be manufactured using a dry process.

The resin with which the glass fiber woven fabric and the aromatic polyamide fiber nonwoven fabric are impregnated is not particularly limited, and may include epoxy resin, phenol resin, polyimide, polyester, polyphtadiene, and the like.

When making a metal foil-covered laminate, the metal foil is molded, especially stacked and integrated, but the metal foil can be copper foil, nickel foil,
Aluminum foil, etc.

Examples 1 to 2, Comparative Examples 1 to 3, Conventional Example 1 Glass fiber woven fabrics with various chemical compositions shown in Table 1 (glass fibers with a diameter of 9μ
0.18mm woven using yarn obtained by converging 0.00 yarns with a number of threads of 43 yarns/25mm in length and 32 yarns/25mm in width.
Thickness woven fabric, basis weight 209g/bo, manufactured by Asahi Schweher),
Para-based aromatic polyamide fiber nonwoven fabric (basis weight 65g/
%, manufactured by Nippon Hi-Lean), a laminate was manufactured as follows.

First, as a resin varnish, epoxy resin (product name: ap
-1001, made by Yuka Shell, epoxy equivalent 500)
A mixture of 100 g, 3 g of dicyancyamide, and 0.2 g of 2-ethyl 4-methylimidazole is prepared.

This varnish is impregnated into the various glass fiber woven fabrics and dried.
Prepreg A with a resin content of 40% by weight was obtained. In addition, by impregnating and drying a para-aromatic polyamide fiber nonwoven fabric, the amount of resin was 83%.
% prepreg B was obtained.

The thickness of one surface composed of Preppu Hana Leg B is 300 mm.
A layer of prepreg B was formed on both sides of the layer of prepreg A so that the thickness of
A double-sided copper-clad laminate with a thickness of 1.6 mm was obtained by heat-pressing molding for 0 minutes.

Drill wear rate: Friction after stacking three laminates and drilling 500 shots with a 1.0φ drill In Example 1, instead of prepreg B, para-aromatic polyamide fiber woven fabric (basis weight 160g/ A prepreg (resin IT: 45% by weight) based on prepreg (Resin IT: 45% by weight) was prepared, and a double-sided copper-clad laminate with a thickness of 1.6 was obtained in the same manner.

When this laminate was drilled with a drill, peeling between the eyebrows was observed on the hole wall.

Table 1 also shows the characteristics of the obtained laminate. The test method for characteristics is as follows.

Capacitance: A copper-clad laminate was etched into a comb-shaped pattern as shown in Figure 2, and measured at 200MH2.

FIG. 1 shows the capacitance of the laminate and the change in the thermal expansion coefficient in the thickness direction of the laminate when the thickness ratio of the prepreg layer of the lath fiber woven fabric is changed. In FIG. 1, the thickness of the para-aromatic polyamide fiber nonwoven fabric layer on the horizontal axis indicates the thickness of the surface layer on one side of the laminate.

From FIG. 1, it can be seen that by setting the thickness of the aromatic polyamide fiber nonwoven fabric layer to 100 μm or more, the capacitance is further reduced and the high frequency characteristics are excellent. However, if the thickness of this layer exceeds 400 μm, the coefficient of thermal expansion in the thickness direction of the laminate becomes impractical in terms of ensuring through-hole conduction reliability.

Effects of the Invention As described above, in a laminate in which a glass fiber woven fabric and an aromatic polyamide fiber nonwoven fabric are combined as base materials, the laminate according to the present invention has a special glass Mi precept of the glass fiber woven fabric. This makes it possible to ensure machinability and further suppress thermal expansion in the plane direction.

Further, in the above-mentioned laminate, since the glass composition is made special, the capacitance is further reduced, and a laminate with excellent high frequency characteristics can be provided.

[Brief explanation of drawings]

FIG. 1 shows changes in capacitance and coefficient of thermal expansion in the thickness direction when the thickness of the layer of para-aromatic boria ξ-doped fiber nonwoven fabric is changed in a laminate according to an example of the present invention. The curve diagram and FIG. 2 are explanatory diagrams of a comb-shaped pattern of electrodes for measuring capacitance.

Claims (1)

[Scope of Claims] 1. A laminate in which a sheet-like base material is impregnated with a resin and then laminated and molded under heat and pressure, in which the base material layer is bonded to a glass fiber woven fabric layer and at least one surface thereof. A laminate consisting of stacked layers of aromatic polyamide fiber non-woven fabric, the glass fiber woven fabric having the following glass chemical composition: SiO_2: 50 to 75% by weight Al_2O_3: 15 to 35% by weight Alkaline earth metal oxide: 5 to 15% by weight Alkali metal oxide: 5% by weight or less to 02, thickness of surface aromatic polyamide fiber nonwoven fabric layer is 100-40
The laminate according to claim 1, which has a thickness of 0 μm. 3. The laminate according to claim 1 or 2, wherein a metal foil is integrated on at least one outermost surface.