JPH02244786A - Composite board for printed circuit - Google Patents

Abstract

PURPOSE:To improve the degree of freedom of circuit design, reduce the number of connections between different types of substrates and the number of components such as connectors and obtain an electronic apparatus with high reliability by a method wherein a composite board which has a different dielectric constant layer in the part of its surface or its inside is employed as the core of a printed circuit substrate. CONSTITUTION:A substrate made of glass cloth, glass paper or the like is impregnated and coated with thermosetting resin such as epoxy resin and polyimide resin and dried to obtain a prepreg. A plurality of the prepregs are laminated, heated and compressed to form a laminated board 1. In order to employ the laminated board as a circuit board, a part 1a where a high frequency circuit is to be formed is hollowed out by punching with a suitable size. A layer 2 having a permittivity different from that of the laminated board 1 and having the same thickness as the laminated board 1 and the same size as the punched part 1a is fitted to the punched part 1a to obtain a composite board 3. The composite board 3 is employed as the core of a printed circuit board. The same prepregs as used for the composite board 3 are provided on both the surfaces of the composite board 3 as insulating layers 4 and, further, a single-sided conductive layer 5 is laminated on the board.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a composite board for printed circuits with partially different dielectric properties, and this composite board has a mixture of high-frequency circuits and general circuits. Used when printed circuits are designed.

(Prior art) Conventionally, a substrate made by laminating and molding prepreg, which is made by impregnating and drying a thermosetting resin into a base material such as glass cloth, and A-foil has been used as a printed circuit board. There is. However, for example, when using a glass cloth base material/epoxy resin prepreg, the dielectric properties of the substrate are
Their values are relatively high, with a dielectric constant of 4.8 and a dielectric loss tangent of about 0°015, making them unsuitable for use as printed circuit boards for high frequency applications.On the other hand, fluororesin-based boards with excellent high frequency characteristics are suitable for use in high frequency applications. The reality is that the cost is too high for use in other general circuits.

(Issues that the invention seeks to solve) Therefore, when forming a printed circuit in which a high-frequency circuit and a general circuit coexist, it is necessary to prepare multiple substrates with different dielectric constants, and as a result, The disadvantage was that the equipment became larger and the cost increased, which was a major constraint on circuit design.Furthermore, fluororesin-based and ceramic-based substrates had lower strength and strength than thermosetting resin-based substrates.
It had drawbacks in through-hole processability, stability, etc., and was not satisfactory.

The present invention was made in order to eliminate the above-mentioned drawbacks in printed circuit design in which high-frequency circuits and general circuits coexist, and it is possible to design a high-frequency circuit at any position on one board, and to process through-holes as a whole. Excellent stability and stability.
The aim is to provide a highly reliable composite board for printed circuits that is smaller, lighter, and lower in cost.

[Structure of the Invention] (Means for Solving the Problems) As a result of intensive research aimed at achieving the above object, the present inventors have developed a composite material having a different dielectric constant layer in the necessary portions as a core. The present invention was completed by discovering that the above object can be achieved by laminated molding.

That is, the present invention provides a printed circuit board having a substantially plate-shaped core, an insulating layer disposed on both sides of the core, and a conductive layer provided on at least one side outside the insulating layer, in which the core is located on the surface of the printed circuit board. Alternatively, it is a composite board for a printed circuit characterized by being a composite material having a different dielectric constant layer in a part of the interior thereof.

The present invention will be explained in detail below.

The composite material used as the substantially plate-shaped core in the present invention has a different dielectric constant layer, that is, a dielectric layer having a dielectric constant different from that of the main dielectric material of the core, on its surface or a part of its interior. The main dielectric material of the core is a laminate made of synthetic resin and a base material such as glass or paper, or a molded product made of synthetic resin and filler.The core is a material with a circuit formed on the surface or inside of the main dielectric material. It may be a wiring board, a multilayer board, or a molded product.

The composite different dielectric constant layer may be present in one place or in multiple places in the core, and a layer with one type of dielectric constant or a layer with multiple types of dielectric constant, such as a low dielectric constant part and a high dielectric constant part, can be used. For example, the composite may be a laminate with a high dielectric constant layer and a low dielectric constant layer on a part of the surface, a part of which is punched out, and a different dielectric constant layer is added thereto. Examples include a fitted laminate, a wiring board with a different dielectric constant layer buried in a part of the inside, a multilayer wiring board partially having a different dielectric constant layer, and a molded product in which a different dielectric constant layer is insert-molded. Possible 1. There are no particular restrictions on the materials of the core-based dielectric material and the dielectric layer having different dielectric constants used here, and various materials can be used. That is, examples of low permittivity dielectrics include fluorine resins, polyester resins, polyetherimide resins,
Examples include laminates and molded products using polyimide resins, and examples of the high dielectric constant layer include ceramic materials, filler-containing laminates, filler-containing molded products, and the like.

The insulating layer used in the present invention is prepared by impregnating, coating, and drying a thermosetting resin on a base material in advance. Semi-cured prepreg or semi-cured thermosetting resin powder is used. Glass cloth, glass vapor, etc. are used as the base material of the prepreg, and examples of the thermosetting resin include phenol resin, epoxy resin, polyimide resin, etc. The resin and base material used for this insulating layer are preferably the same as the resin and base material of the main dielectric of the composite, but may be different.

In the present invention 1. ': The conductive layer to be used may be any one as long as it can form a circuit, such as metal foil, plating layer, conductive base I-layer, etc. When using metal foil such as m-foil, the substrate of the present invention The conductive layer can be formed as an integral layer as the outermost layer during manufacturing, and is suitable for mass production, so it has great manufacturing advantages.The conductive layer can be on one side, but if it is on both sides, copper foil-copper foil or copper foil-plating is used. The composite substrate of the present invention may be a double-sided conductive layer combination such as a plating layer (using an additive method) or a plating layer-plating layer. It is fine if two or more sets are laminated with another insulating layer interposed therebetween.

Next, the composite substrate of the present invention will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view of a composite substrate stand whose core is a composite material in which a portion of a laminate 1 is punched out and a different dielectric constant layer 2 is inserted therein.

Composite 3 in Fig. 1 is made by first preparing prepreg by impregnating, coating, and drying a thermosetting resin such as epoxy resin or polyimide resin on a base material such as glass sheet or glass paper. Prepare a high-quality laminate 1 by stacking multiple sheets and forming them under heat and pressure.As shown in Fig. 2(a), punch a portion 1a that will become a high frequency circuit when used as a circuit board to an appropriate size. Hollowed out by processing, etc., the punched part 1a is fitted with a single layer 2 having the same thickness as the laminate 1 and the same size as the punched part 1a, as shown in Fig. 2cb>. able to make.

The composite substrate 6 in FIG. 1 has the above composite 3 as a core, the same prepreg used for the composite 3 is placed on both sides to form an insulating layer 4, and a single-sided conductive layer 5 is further laminated on the surface of the substrate. It is molded.

The heteroglot single layer 2 of the composite Ia3 may have any pattern, for example, the O-type heteroglot single layer 32 in FIG. 3, the P in FIG.
It may be a single layer 42 of a type of different language electrode, or a single layer 52 of different language electrodes provided with a plurality of holes 7 for through poles as shown in FIG.

In FIG.
FIG. 3 is a cross-sectional view of a composite substrate having a core made of a composite material 63 in which a monolayer 62b is embedded and a monolayer 62b is formed on the -S portion of the surface of a laminate l. As in FIG. 1, the core has an insulating layer 4 and conductive layers 5 formed on both outer surfaces thereof.
Like the foreign language single layer 62a, the foreign language single layer does not need to be embedded inside the laminate 1 and not exposed on the core surface.

In addition, when there are multiple different language single layers such as the different language single layers 62a and 62b, the different language single layers may be different from each other. It is necessary to select a pattern.

Furthermore, this composite 63 may be incorporated in multiple layers instead of one layer.Also, in order to make the intended purpose more effective, the single layer existing in the composite may be cut out. It can also be exposed and used as a chip on board (COB).

(Function) If a composite material having a single dielectric layer on the core surface or part of the inside of the core is used as the core of a printed circuit board, the dielectric properties of the composite board will be partially different, and the high frequency circuit will be can be incorporated on the index layer. Furthermore, to increase the effect, the insulating layer of the substrate can be shaved off to expose a portion of the monolayer, and the chip can be placed there, allowing it to be used as a chip-on-board. Furthermore, since the high dielectric constant layer, the single layer of paper stuffing, or both can be arbitrarily arranged on the substrate, it is extremely advantageous in terms of circuit design. Since the core of the composite can be made of a synthetic resin laminate with an ordinary glass substrate, the same method as for conventional glass-based printed circuit boards can be applied to small-diameter through-hole holes. You can get something highly reliable.

(Examples) Next, the present invention will be specifically explained by examples, but the present invention is not limited to the following examples.

Example 1 A glass epoxy laminate TLB-551 (manufactured by Toshiba Chemical Co., Ltd., trade name) of 520 x 400 x 0.5 mn was coated with a second
300 mm with a punching press as shown in part 1a of Figure (a).
Die-cut out pieces with dimensions of x 150 x 0.5 ml. P of the same size and thickness as the next punched part
After chemically treating the TFE plate, it is fitted into the punched portion 1a of the glass epoxy laminate as shown in FIG. 2(b).
As shown in Figure 1, the PTFE plate is fitted into one piece, the resulting glass epoxy laminate is made into a composite, epoxy prepreg is placed on both sides, and a thickness of 1.
Layer 8μ electrolytic copper foil, sandwich between stainless steel plates, and press at 175℃.

Molded for 180 minutes at 40kg/c12, thickness 1,6
A composite board for a printed circuit of No. 11i was manufactured. The dielectric constant of the upper part of the P TFE board of this composite board was 2.8, and the dielectric constant of the other parts was 4.8. In addition, similar to the glass substrate laminate, component holes and conductive holes could be easily processed, and the reliability was high, thus confirming the effects of the present invention.

Implementation pA2 520x 400x0.6 [1] Take the glass polyimide laminate '1' I,B-583 (manufactured by Toshiba Chemical Co., Ltd., trade name), and cut a portion of size 250x 400x0.6 ni with a router. do. Next, a PTFE plate of the same size that had been processed and treated was inserted into this processed part to create a composite.
Polyimide prepreg TLP-583 (manufactured by Toshiba Chemical Co., Ltd., trade name) was layered on both sides of the composite of the board and PTFE board, and electrolytic copper foil with a thickness of 18 μm was placed on both sides, and then Place this between stainless steel plates,
23 at a temperature of 195℃ and a pressure of 45kg/cI12.
By molding for 0 minutes, a printed circuit composite substrate having a thickness of 1.6 nLI was manufactured. When the dielectric constant of the upper part of the PTFE plate of this composite substrate was measured, it was 2.7, and the dielectric constant of the other part was 4.8. Further, component holes and conductive holes similar to those of the glass substrate laminate could be easily and reliably processed, confirming the effects of the present invention.

Example 3 A composite board for a printed circuit was manufactured in the same manner as in Example 2 except that polyetherimide was used instead of PTFE. The resulting composite substrate was counterbored to expose the polyetherimide portion and used for chip-on-board, and the non-exposed portion was used for component holes and conduction holes. These could be processed easily and reliably, and the effects of the present invention were confirmed.

Example 4 A composite board for a printed circuit was obtained in the same manner as in Example 1 except that ceramic was used instead of PTFE. The dielectric constant of the ceramic upper part of this composite substrate is 8.5
Moreover, the processing of component holes and conduction holes was easy and reliable, and the effects of the present invention were recognized.

[Effects of the Invention] As explained above, the composite board for printed circuits of the present invention allows for highly reliable processing of component holes and conductive holes similar to those of general glass substrate laminates, and also enables It is possible to assemble high-frequency circuits on the dielectric constant layer, providing a greater degree of freedom in circuit design, and by connecting dissimilar substrates and reducing parts such as connectors, highly reliable electronic devices can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view of a composite board for printed circuits according to an embodiment of the present invention, Figures 2 (a) and (b) are perspective views showing the manufacturing process of the composite used for the first national flag composite board, and Figure 3. ~ Figure 5 is a perspective view showing another composite used in the composite substrate of the present invention, Figure 6
The figure is a sectional view showing another embodiment of the composite substrate of the present invention. 1... Laminate plate, 2.32, 42, 52.62a. 62b...Koyuden single layer, 3.63...Composite,
4... Insulating layer, 5... Conductive layer. Figure 1 2rX! Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In a printed circuit board having a substantially plate-shaped core, an insulating layer disposed on both sides of the core, and a conductive layer provided on at least one side outside the insulating layer, the core is partially on its surface or inside. A composite board for a printed circuit, characterized in that it is a composite material having a dielectric constant layer.