JPH0250834A - Laminated sheet - Google Patents

Abstract

PURPOSE:To obtain a printed circuit board excellent in processability and having a high dielectric constant by laminating a plurality of prepregs, each of which is formed by impregnating a base material with resin varnish with which a ceramic staple fiber based on Si3N4 and a powder having a specific dielectric constant are compounded to dry the impregnated one, and integrally laminating a metal foil to the outermost layer thereof. CONSTITUTION:As a base material, a paper base material, org. fiber cloth and glass cloth can be employed but the glass base material having a high dielectric constant is pref. This base material is impregnated with resin varnish and dried to prepare a prepreg. As a resin, an epoxy resin, a polyimide resin, a polyester resin or the like can be employed. A ceramic staple fiber based on Si3N4 is compounded with the resin varnish before said varnish is contained in the base material. The ceramic staple fiber pref. has a dielectric constant of 9 or more and the compounding amount thereof with the resin varnish is set to a range of 10-50wt.% as solid concn. A powder having a dielectric constant of 500 or more is compounded with the resin varnish before said varnish is contained in the prepreg. As the powder, BaTiO3 can be employed and is compounded with the resin varnish in an amount of 10-50wt.% as solid concn.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a laminate in which a base material contains short ceramic fibers and powder with a high dielectric constant.

[Conventional technology]

With the arrival of the information society, there is a desire to significantly expand communication capacity, and the use of optical fibers for wired systems and high frequencies for wireless systems has become concrete. In terms of wireless high frequency, for example, a car phone that used to have a band of 400 MHz has a band of 900 MHz.
A shift to the Hz band or 1.3 GHz band is planned. High-frequency printed circuit board materials used for this purpose are required to have particularly excellent dielectric properties, that is, dielectric constant and dielectric loss tangent, in addition to the conventionally desired performance. By the way, since upstream electrical circuits have conventionally been designed using lumped constant circuits, insulation, dimensional stability, workability, etc., have been considered important for printed circuit board materials. On the other hand, for high-frequency circuits, the design concept of distributed constant circuits is essential in addition to lumped constant circuits, and the dielectric constant of printed circuit board materials is an important physical constant that determines essential parameters of distributed constant circuits such as characteristic impedance and wavelength shortening rate. The need to handle it is increasing. For example, as the dielectric constant increases, there is an advantage that the base material can be made smaller in terms of an equivalent circuit of distributed constants. That is,
If you design a circuit with the same performance using a distributed constant using a glass epoxy laminate and an alumina ceramic board, the latter will be about 1/1 of Moe's.
This is possible with an area of 2.

[Problem to be solved by the invention]

Ceramic substrates cannot be used as printed circuit board materials due to difficulties in processability. Furthermore, the dielectric constant was also constant, making it impossible to adjust it depending on the application. The present invention has been made to solve the above problems, and its purpose is to use ceramic fibers with excellent workability to adjust the dielectric constant, have excellent dimensional stability, and have a high dielectric constant. It is an object of the present invention to provide a laminate board which has an extremely high resistance, which can be miniaturized as a printed wiring board, and which can be suitably used as a printed circuit board material for high frequency equipment.

[Means to solve the problem]

The present invention is a laminate in which a plurality of prepregs formed by impregnating and drying a resin varnish on a base material are laminated and a metal foil is laminated and integrated on the outermost layer of the prepreg.
It is characterized by blending short M&fibers of ceramic fibers mainly composed of i3N4 with powder having a dielectric constant of 500 or more, and this structure solves the above problems. 1 Effect] Since the base material contains short fibers of ceramic fibers mainly composed of Si3N4, which are blended into the resin varnish, there is no problem with workability, and the high dielectric constant of ceramic can be utilized. Since it contains powder with a dielectric constant of 500 or more, it has an extremely high dielectric constant, making it suitable for use as a printed circuit board material for high-frequency equipment.It also has excellent N-method stability due to the short fibers of ceramic base fibers. Moreover, the dielectric constant can be adjusted by changing the blending amount. The present invention will be explained in detail below. As the base material, a paper base material, a PIi fiber cloth, a nonwoven fabric, a glass cloth, a glass cloak, etc. can be used, but a glass base material with an extraordinary dielectric constant is preferable. This base material is impregnated with resin varnish and dried to prepare a prepreg. As the resin, epoxy resin, polyimide resin, polyester resin, fluororesin, polybutadiene resin, PPO resin, etc. can be used, but a resin with a small dielectric loss tangent is preferable. This O (S in the fat varnish)
Ceramic WL+Ilt short fibers mainly composed of i and N are blended and contained in the base material. The ceramic short fibers preferably have a dielectric constant of 9 or more. As the ceramic fiber, for example, ceramic fiber made by Sangopan Co., Ltd. made into chips or woven fabric made into chips can be used. The length of ceramic short fibers is 30-20
Preferably, the diameter of the filament is 0μ, and the diameter of the filament is 7 to 20μ. The amount of ceramic staple fibers added to the resin varnish can range from 10 to 50% by weight in terms of solid content. Further, a powder having a dielectric constant of 500 or more is blended into the resin varnish, so that the prepreg contains the powder. BaTiOs or the like can be used as this powder, and the blending ratio in the resin varnish is 10 to 50% by weight in terms of solid content. A plurality of prepregs prepared in this manner are stacked, a metal foil is placed on the outermost layer, and the prepregs are placed between heating platens via forming plates as a set. /cm2. Manufactured by heating and pressurizing for 40 to 100 minutes to integrate the layers. This laminated board is sequentially subjected to hole drilling, electroless plating, pattern formation, pattern plating, resist plating, resist removal,
For example, through-hole plated printed wiring boards are manufactured through processes such as etching, external finishing, and symbol mark printing. Next, examples of the present invention will be specifically described. (Example 1) In epoxy resin varnish, solid content of short A fibers prepared by chipping ceramic fiber cloth (manufactured by Sango Pan Co., Ltd. [Cross #18J) with a dielectric constant of 18 and having a length of 100 μm and a filament diameter of 9 μm and BaTiO3 was added to the epoxy resin varnish. A resin varnish was prepared by blending the resin in a proportion of 15% by weight. Next, a glass cloth was impregnated with resin varnish and dried to prepare a prepreg having a resin content (solid content) of 50% by weight. This prepreg was stacked on concave plates, copper foil was placed on both sides, and the plates were heated and pressed together at 170° C. and 30°C to produce a laminate with a thickness of 0.8 mm. The dielectric constant and dielectric loss tangent of this laminate were measured, a circuit pattern was formed, a printed wiring board (PWB) was manufactured, and the dimensional change rate and the required size were compared using Comparative Example 1 as a standard. The results are shown in Table 1. (Example 2) A laminate was manufactured in the same manner as in Example 1, except that a 77-layer resin varnish was used instead of the epoxy resin varnish, and the laminate was integrated under heat and pressure at 370'C130kg/am2, and the same measurements were carried out. went. The results are shown in Table 1. (Comparative Example 1) A laminate was produced in the same manner as in Example 1, except that glass cloth was impregnated with resin varnish and dried to prepare a prepreg with a resin content (solid content) of 50% by weight, and the same measurements were carried out. Ta. The results are shown in Table 1. (Comparative Example 2) A laminate was produced in the same manner as in Example 1, except that short ceramic i-fibers were not used, and the same measurements were performed. The results are shown in Table 1. Table 1 Dielectric constant Dielectric loss tangent dimensional change rate PWB () Size example 1 12,0 0.005 0.03
402 8.0 0.0007 0.04 6
0 Comparative Example 1 4,8 0.01 0.05
1002 1.0,0 0,005 0.
05 48 From the results in Table 1, it is possible to reduce the size of the printed wiring board by 40% or more compared to Comparative Example 1 in the example, and it has superior dimensional stability compared to Comparative Example 2. is understandable.

【Effect of the invention】

The present invention is a laminate in which a plurality of prepregs formed by impregnating and drying a resin varnish on a base material are laminated and a metal foil is laminated and integrated on the outermost layer, and the resin varnish contains Si3N.
Since the short fibers of Ceramink fibers mainly composed of + and powder with a dielectric constant of 500 or more are blended, the short fibers of Ceramink fibers contained in the base material have no problem with processability and have high ceramic properties. dielectric constant can be used,
Moreover, since the base material contains powder with a dielectric constant of 500 or more mixed into the resin varnish, the dielectric constant becomes extremely high.
Can be suitably used as a printed circuit board material for high frequency equipment.
Furthermore, the short a fibers of the ceramic NiJ,a provide excellent dimensional stability, and the dielectric constant can be adjusted by changing the blending amount. Agent Patent Attorney Ishi 1) Chief 7 Procedural Amendments (spontaneous) 1. Indication of the case Patent Application No. 202321 of 1988 2. Name of the invention laminate 3. Person making the amendment Relationship to the case Patent applicant address 1048 Bold Kadoma, Kadoma City, Osaka Prefecture Name (58
3) Matsushita Electric Works Co., Ltd. Representative Toshio Miyoshi 4, Agent postal code 530 5, Date of amendment order 6, Number of claims increased by amendment None 1) Section 5 of the specification, line 1, `` 7-20μm” will be corrected to “5-20μm”. 2) Change “10 to 50” on page 5, line 17 of the above to [10 to
I will correct it to 80.

Claims (2)

[Claims] (1) A laminate in which a plurality of prepregs formed by impregnating and drying a resin varnish on a base material are laminated and metal foil is laminated and integrated on the outermost layer, and the resin varnish contains Si_3N_
Short fibers of ceramic fiber mainly composed of 4 and dielectric constant of 50
A laminate characterized by containing 0 or more powders. (2) The laminate according to claim 1, wherein the ceramic fiber has a dielectric constant of 9 or more.