JPH03190729A - Laminated board - Google Patents

Abstract

PURPOSE:To manufacture a laminated board having a high dielectric constant easily, and to improve the distribution of an electrostatic coefficient in the laminated board remarkably by using glass cloth composed of glass fibers having a dielectric constant of ten or more as a base material. CONSTITUTION:Glass cloth consisting of glass fibers having a dielectric constant of ten or more is employed as a base material, thus obtaining a desired laminated board. Accordingly, the dielectric constant is improved, and workability, mechanical characteristics and dimensional stability are enhanced while the manufacture of the laminated board is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminate for high frequency printed wiring boards used in telecommunications equipment, electronic equipment, industrial equipment, etc.

[Prior Art] In recent years, printed wiring boards have been used in an extremely wide range of applications, and accordingly, the characteristics required for laminates for printed wiring boards have also become diverse. Among these, laminates for printed wiring boards used in high frequency regions such as the UHF or SHF band are required to have a low dielectric loss tangent and, in particular, a high dielectric constant in order to miniaturize circuits. There is. Along with these, it is also essential to have excellent high-frequency properties, that is, a constant dielectric constant and dielectric loss tangent over a wide frequency range, temperature range, and humidity range.

Conventionally, alkali-free glass fibers called E-glass have been widely used for glass fiber-reinforced laminates for printed wiring boards because of their good electrical insulation, easy fiberability, and low cost. However, since its dielectric constant is 5 to 6, the dielectric constant of the obtained glass fiber reinforced laminate is 4.5 to 5.5 when the widely used epoxy resin is used as a binder, and the circuit This did not satisfy miniaturization. Therefore, a ceramic (for example, alumina) substrate is used as the high dielectric constant laminate.

This ceramic substrate has a dielectric constant higher than that of an organic substrate made of epoxy resin or the like by about the diameter of IO. However, compared to organic substrates, it is inferior in processability and is more expensive. In order to overcome these problems, we added an appropriate amount of inorganic powder such as barium titanate or strontium titanate to a thermosetting resin, and then laminated the required number of prepregs obtained by sprinkling glass on the resin or impregnating and drying glass nonwoven fabric. An attempt has been made to obtain a glass-based resin laminate having a high dielectric constant by molding (Japanese Patent Laid-Open No. 61-167547). In this case, a high dielectric constant laminate with improved workability can be obtained through a process similar to the conventional method. Furthermore, attempts have been made to obtain a glass base resin laminate with a high dielectric constant and excellent high frequency characteristics by adding inorganic powder with a high dielectric constant to a fluororesin or polyphenylene oxide resin (Japanese Patent Laid-Open No. 61-286128, 1983). -2i7239).

Uniformly dispersing the inorganic powder added to the resin in order to obtain a high dielectric constant laminate with improved processability is a very complicated process, and dielectric loss due to non-uniform dispersion within the glass fiber cloth There are problems with variations in ratio and dimensional stability. In addition, the dielectric voltage contact of inorganic powder is relatively large, and adding a large amount to increase the dielectric constant increases the dielectric loss tangent and further causes a problem of a decrease in mechanical strength.

[Problem K to be solved by the invention] The present invention makes it possible to achieve a high dielectric constant by using a glass fiber cloth with a high dielectric constant, and by reducing the amount of inorganic powder added to the resin or by adding no inorganic powder. In addition to reducing the complexity of the process, the present invention aims to solve problems such as deterioration in the performance of the produced high dielectric constant laminate, such as non-uniformity of the dielectric constant of the laminate, high dielectric loss tangent, and decrease in mechanical strength.

[Means for Solving the Problems] The structure of the present invention for solving the above problems is characterized in that (1) a glass cloth made of glass fibers having a dielectric constant of 10 or more is used as a base material; Laminated board.

(2) The laminate according to item (1) above, wherein the content of PbO in the glass fibers is 60% by weight or more.

The present invention is a laminate in which a glass cloth made of glass fibers with a dielectric constant of 10 or more is used as a base material, so it has a high dielectric constant, and has excellent processability, mechanical properties, and dimensional stability, and is superior to conventional It has become possible to obtain a small-sized laminate to which the process method can be applied as is. The present invention will be explained in detail below.

The dielectric constant of a glass fiber-reinforced laminate is approximately expressed as the sum of the volume fractions of the dielectric constants of the constituent glass and resin themselves. Therefore, although it is affected by the dielectric constant of the resin used as a binder, in order to obtain a dielectric constant equivalent to that of a ceramic substrate required for miniaturization of circuits, it is necessary to use a glass substrate with a dielectric constant of 10 or more. is necessary. Furthermore, since the base material used for the laminate is desired to have high insulation properties, it is undesirable for the base material to contain alkali metal components and the like. As such a high dielectric constant glass, a glass having a PbO content of 60% by weight or more is preferable. However, although other glass components may affect the dielectric constant of the glass, a dielectric constant of 10 or more can be achieved by combining with 5iOz, which is a typical glass component. In addition, as the glass fiber cloth serving as the base material, it is possible to use twill weave, satin weave, hand-woven glass fabric, glass non-woven fabric, etc., but in order to increase the glass content in the laminate, it is possible to use dimensional stability. For improvement, it is desirable to use hand-woven glass cloth.

The resins used in the present invention include phenolic resins, cresol resins, epoxy resins, unsaturated polyester resins,
It is possible to use polyimide resin, polybutadiene resin, polyamide resin, polyphenylene oxide resin, fluororesin, etc. singly, modified products, mixtures, etc., but the high frequency properties, dielectric constant, dielectric loss tangent, etc. required for the laminate can be used. It is selected as appropriate depending on the characteristics. Of course, in that case, the resin used does not impair the effect of increasing the dielectric constant of the laminate using the high dielectric constant glass fiber cloth base material. In addition, the desired dielectric constant can be obtained by changing the volume fraction of the resin used and the high-frequency glass fiber cloth base material in the laminate, or by combining the high dielectric constant glass fiber cloth base material or the E-glass fiber cloth base material. It becomes possible to obtain a board. Furthermore, in a multilayer printed wiring board, a high dielectric constant glass fiber cloth base material is used only between layers that require a high dielectric constant, and E glass fiber cloth base material or other glass fiber cloth base material is used between other layers. It is possible to obtain a laminate having a desired dielectric constant distribution by a method such as the following. It goes without saying that the laminate according to the present invention can be produced using ordinary equipment for manufacturing glass fiber reinforced laminates.

[Example] The present invention will be specifically described below based on examples.

Example] Consisting of warps and wefts of high dielectric constant glass filaments listed in Table 1 below, with a density of warp 40/25I and weft 32/2
A glass fiber fabric having a plain weave structure of 5m11 was woven, impregnated with an epoxy resin varnish having the following formulation example, and dried by heating at 125°C to produce a 50cm square prepreg. Eight sheets of this prepreg were layered with 35 μm copper foil on the surface and compression molded at 175° C. and 20 kg/cm′ to obtain a copper-clad laminate with a thickness of 1.6 I. After that, this laminated board is 100II! It was divided into four parts and the dielectric constant of each part was measured.

The fabric properties of Example 1 are shown in Table 2, and the dielectric constant and dielectric loss tangent of the laminate are shown in Table 3.

Resin varnish formulation APR-711 (Fushikasei epoxy resin) 100 parts Dicyandiamide 2.5 parts Benzyldimethylamine 0.2 parts Dimethylformamide 12 parts Methyl cellosolve
12 parts Methyl ethyl ketone 25 parts Example 2 The glass fiber woven fabric woven in Example 1 was impregnated with the tetrafluoroethylene resin dispersion, then melted and cooled to produce a prepreg. A polytetrafluoroethylene resin film with a thickness of 30 μm is placed on the top and bottom surfaces of the 8 sheets of prepreg stacked together, and copper foil with a thickness of 35 μm is further layered on the top and bottom surfaces of the 400
C. and compression molded at 20 kg/cm2 to obtain a copper-clad fluororesin laminate having a thickness of 1.61 mm. The results of Example 2 are
Shown in Table and Table 3.

Comparative Example 1 Composed of warp and weft of E glass long fibers listed in Table 1 below, density of warp 40/25m+n, weft 32/25m
A copper-clad laminate was obtained in the same manner as in Example 1 by weaving a glass fiber fabric consisting of M and having a hand-woven texture. The results of Comparative Example 1 are shown in Tables 2 and 3.

Comparative Example 2 A copper-clad laminate was produced in the same manner as in Example 1 using the glass fiber fabric woven in Comparative Example 1 and a varnish containing 100 parts by weight of barium titanate based on 100 parts by weight of the resin used in the example. I got it. The results of Comparative Example 2 are shown in Tables 2 and 3.

Note: Ingredients are in weight% 5.12.

[Effects of the Invention] As explained above, the laminate according to the present invention has a dielectric constant of 10.
It is characterized by the use of glass fiber cloth made of the above-mentioned glass fibers, and therefore it is possible to easily produce a high dielectric constant laminate that can miniaturize circuits using conventional manufacturing equipment, manufacturing conditions, and resin. Become.

Furthermore, the electrostatic weight distribution in the laminate is Much improved.

Claims (2)

[Claims] (1) A laminate characterized in that a glass cloth made of glass fiber having a dielectric constant of 10 or more is used as a base material. (2) The laminate according to claim (1), wherein the content of PbO in the glass fibers is 60% by weight or more.