JPH08111571A - Laminated board for printed circuit - Google Patents

Abstract

PURPOSE: To realize a laminated board used for a printed circuit and excellent in through-hole reliability and low in both expansion coefficient and dielectric constant by a method wherein some pieces of glass densely-woven cloth base material diagonally woven out of glass fine yarns of a certain yarn count ECG above a specified value are impregnated with specified resin composition and thermocompressed into an insulating layer. CONSTITUTION: 67 parts of epoxy resin EXA 7200 possessed of dicyclopentadiernyl skeletons and 33 parts of tetrabromobisphenol A are compounded with 25.3 parts of phenol resin DPP-600M possessed of dicyclopentadienyl skeletons as curing agent to serve as resin composition. The resin composition is dissolved into methyl etchyl ketone, which is used as laminating varnish. A high-density glass cloth A6777 of thickness 0.10mm is impregnaged with the above laminating varnish, and the varnish is set into a semicured state by drying to form the glass cloth into a laminating prepreg which contains 30% resin by weight. 10 sheets of the prepreg are laminated, and a copper foil of low expansion coefficient is provided to the upper and lower side of the laminate respectively, which is sandwiched in between stainless steel plates and thermocompressed into a printed circuit laminated board of thickness 0.8mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for mounting a semiconductor device in a package form having a small coefficient of thermal expansion such as CLCC, TSOP, etc., and has a low expansion coefficient and a low dielectric constant, which has excellent through-hole reliability and is laminated for printed circuits. Regarding boards and prepregs.

[0002]

2. Description of the Related Art Recent technological innovation has been remarkable, and downsizing of electronic devices has never stopped. This is due to high-density packaging technology, high integration of semiconductors, and miniaturization technology of semiconductor packages.
A semiconductor device such as TSOP having a smaller package size than a semiconductor chip size has been widely used. Also,
High-density mounting technology and high integration of semiconductors are also aimed at speeding up the driving of electronic equipment. Even if a low-dielectric constant substrate with a high signal transmission speed and a high-speed clock are used, there are few errors with low error. The demand for dielectric loss tangent substrates is increasing.

[0003]

However, a base material such as glass cloth, which has been conventionally used as a laminated board for a printed circuit of industrial equipment, has a prepreg and a copper foil impregnated with a thermosetting resin and dried. The copper clad laminate formed by heating and pressurizing integrally is not necessarily suitable for mounting a semiconductor device such as CLCC or TSOP. The package material of CLCC is ceramics, and its coefficient of thermal expansion is greatly different from that of a commonly used glass-based epoxy laminated board.
Does not have leads that absorb thermal stress. Even if the package material is epoxy resin encapsulant, TSOP has a small amount of resin encapsulant for the silicon chip, the overall coefficient of thermal expansion is much smaller than that of the conventional package, and the leads are also very short. . Therefore, when both are mounted on a glass-based epoxy laminate, there is a drawback that solder crack defects frequently occur due to mismatch of thermal expansion coefficients.

The present invention has been made in view of the above circumstances, and is suitable for mounting a semiconductor device in a package form having a small coefficient of thermal expansion such as CLCC and TSOP, which has a low coefficient of expansion excellent in through hole reliability, An object of the present invention is to provide a low dielectric constant printed circuit board and a prepreg used for the same.

[0005]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the inventors of the present invention can achieve the above object by using a specific resin composition and a specific base material. The present invention has been completed and the present invention has been completed.

That is, according to the present invention, in a laminated board for a printed circuit in which a conductive layer is provided on at least one surface of an insulating layer, a glass high density woven fabric base material in which glass thin yarns having a yarn count of ECG 100 or more are obliquely woven as an insulating layer. A low expansion resin composition containing (A) an epoxy resin having a dicyclopentadienyl skeleton, (B) a tetrabromobisphenol A and (C) a phenol resin having a dicyclopentadienyl skeleton as essential components is applied to It is a laminated board for a printed circuit, characterized by being formed integrally by heating and pressurization using an impregnated and dried prepreg. Further, it is a prepreg used for the printed circuit board laminate.

The present invention will be described in detail below.

The laminated board for a printed circuit of the present invention uses a prepreg obtained by impregnating and drying a resin composition on a substrate as an insulating layer. The base material used here is called a weave. It is a high-density glass high-density woven fabric with a high isotropy, as if two thin glass threads arranged in parallel without twisting were regarded as one thick thread and were plain woven. There are no particular restrictions on the style of the base material, but considering the impregnation properties of the resin composition, compatibility with various board thicknesses, application to multi-layer printed wiring boards, etc., weaving materials with several different thicknesses in the range of 30 to 300 μm. It is preferably cloth.

As the resin composition to be impregnated into the base material used in the present invention, a resin composition in which a solvent is added to adjust the viscosity so that the base material can be easily impregnated is used. This resin composition contains (A) an epoxy resin having a dicyclopentadienyl skeleton, (B) a tetrabromobisphenol A, and (C) a phenol resin having a dicyclopentadienyl skeleton as essential components. is there.

The epoxy resin having a dicyclopentadienyl skeleton (A) used here is, for example, EXA.
7200 (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) and the like can be used, and these can be used alone or in combination. To adjust the glass transition point of the resin composition, a liquid epoxy resin or a polyfunctional epoxy resin can be blended. As the (B) tetrabromobisphenol A, those which are usually used can be widely used. Tetrabromobisphenol A is used as a flame retardant, and it is desirable that the content of bromine be 15% or more with respect to the total resin solid content. Examples of the (C) phenolic resin having a dicyclopentadienyl skeleton include DPP-600M (trade name, manufactured by Nippon Petrochemical Co., Ltd.), and these can be used alone or in combination. A resin composition can be easily prepared by mixing these components.

A varnish is prepared by adding a solvent to this resin composition. The varnish contains a colorant, a reinforcing agent, and a filler having a high thermal conductivity or a low dielectric constant within a range not deviating from the object of the present invention. You can Examples of the filler having good thermal conductivity include aluminum hydroxide and silica, and examples of the low dielectric constant filler include fluororesin powder and hollow glass beads. If necessary, talc, calcium carbonate, etc. may be appropriately mixed. The varnish thus obtained is impregnated into the above-mentioned base material and dried to form a prepreg, and this prepreg is used as an insulating layer.

In the present invention, the conductive layer formed on at least one surface of the insulating layer may be a metal foil, a metal plating layer, a conductive paste layer or the like, which can form a circuit. In particular, when using a metal foil such as a copper foil, a plurality of the above-mentioned prepregs are stacked, the metal foil is arranged on at least one surface of the prepreg, and the metal foil is sandwiched between stainless steel plates and integrally laminated by heat pressing. Since the conductive layer can be formed, it is suitable for mass production and has a great manufacturing advantage. When a metal plating layer is used, a laminated plate with an adhesive is prepared and only the necessary portion is plated on the surface of the adhesive to form a conductive layer. When a circuit is formed of a conductive paste layer, the conductive layer can be formed on the surface of the laminated plate by screen printing or the like.

By laminating the above-mentioned metal foil and prepreg and integrally molding under heating and pressure, a laminate for a printed circuit having a low expansion coefficient and a low dielectric constant can be manufactured. The printed circuit laminated board thus manufactured can be suitably used as a circuit board for mounting a semiconductor device such as CLCC or TSOP having a small coefficient of thermal expansion in the surface direction.

[0014]

The printed circuit laminate of the present invention can have a low expansion coefficient and a low dielectric constant by using a resin composition having a specific dicyclopentadienyl skeleton and a specific oblique weave base material. It was made.

That is, the epoxy resin having a dicyclopentadienyl skeleton having a polycyclo structure has a smaller expansion coefficient than the bisphenol A type epoxy resin which is usually used, and has a lower density than the bisphenol A type epoxy resin. A small amount of resin is required to obtain a laminated plate having a thickness, and the low expansion effect can be further enhanced. The dicyclopentadienyl skeleton is a hydrocarbon skeleton and can contribute to the reduction of the dielectric constant of the resin.
The hardener phenolic resin also has a dicyclopentadienyl skeleton.

[0016] Further, conventionally, it is general to use a brominated epoxy resin as a flame retardant, but it is necessary to add a considerable amount of brominated epoxy resin in order to obtain a certain level of flame retardancy, and the resin characteristics are not small. Although it had an influence, by using tetrabromobisphenol A as the flame retardant, it was possible to suppress the influence on the resin characteristics to the minimum and to make the flame retardant.

The oblique weave used in the present invention is smooth, thin, and high in density when compared with a plain woven cloth which is usually used as a base material for producing printed wiring boards in the same basis weight. Therefore, when viewed from the cross section of the woven fabric, the vertical movement of the yarn is small, and there is little room for stretching with respect to the stretching force. In addition, since the height of the crossing points of the vertical and horizontal threads is low and the surface is smooth, the measling resistance is good. Therefore, the amount of resin can be reduced and the expansion coefficient of the entire substrate can be reduced while maintaining the measling resistance equal to or higher than that of the conventional substrate.

The low expansion properties of the resin composition and the weave base material are effective in both the plane direction and the thickness direction of the laminate, and C
It is possible to obtain an excellent laminated board for a printed circuit, which has a mounting connection stability of a semiconductor device having a low expansion coefficient and a low dielectric constant such as LCC and TSOP and a high through hole stability.

[0019]

EXAMPLES The present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

EXAMPLE Epoxy resin EX having dicyclopentadienyl skeleton
A7200 (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) 67
Part, tetrabromobisphenol A 33 parts, a phenol resin DPP-600M (manufactured by Nippon Petrochemical Co., Ltd.) having a dicyclopentadienyl skeleton as a curing agent 2
A resin composition was prepared by mixing 5.3 parts. This composition was dissolved in methyl ethyl ketone to prepare a laminating varnish. This varnish is coated on a high-density glass cloth A6 with a thickness of 0.10 mm.
777 (manufactured by Asahi Schebel, trade name) was impregnated and dried to obtain a semi-cured state to obtain a prepreg for lamination having a resin weight of 30%. Low expansion copper foils are placed on both sides of these 10 prepregs, sandwiched between stainless steel plates, and integrally molded by heating and pressing to a thickness of 0.8.
mm printed circuit board laminates were manufactured.

Comparative Example A 0.8 mm-thick general-purpose glass substrate laminate for epoxy printed circuits (FR-4 grade) was prepared.

The printed circuit laminates of Examples and Comparative Examples were tested for thermal expansion coefficient, TSOP connection stability and through hole reliability. The results are shown in Table 1.
The present invention is excellent in the balance of each characteristic, and the effect of the present invention was confirmed.

[0023]

[Table 1] * 1: Thermal expansion coefficient measurement range CTE _α1 25 to 125 ° C * 2: TSOP connection stability and through hole reliability test conditions Air heat cycle, -40 ° C ・ 1h to + 150 ° C ・ 1h

[0024]

As is clear from the above description and Table 1, the printed circuit laminate of the present invention has a small coefficient of thermal expansion, excellent through-hole reliability, high-speed transmission, and waveform retention. It is suitable for mounting semiconductor devices such as CLCC and TSOP.

Claims (2)

[Claims] 1. A printed circuit laminate having an electrically conductive layer provided on at least one surface of an insulating layer, wherein a glass high-density woven fabric base material obtained by laminating a glass thin yarn having a yarn count of ECG 100 or more as an insulating layer, A) Epoxy resin having dicyclopentadienyl skeleton, (B) Tetrabromobisphenol A
And (C) a low-expansion resin composition containing a phenol resin having a dicyclopentadienyl skeleton as an essential component, is integrally molded by heating and pressurizing using a prepreg which is impregnated and dried. Laminated boards for printed circuits. 2. A printed circuit laminate having a conductive layer on at least one surface of an insulating layer, wherein a glass high-density woven fabric base material in which glass fine yarn having a thread count of ECG 100 or more is woven as an insulating layer, A) Epoxy resin having dicyclopentadienyl skeleton, (B) Tetrabromobisphenol A
And (C) a low-expansion resin composition containing a phenol resin having a dicyclopentadienyl skeleton as an essential component, coated, impregnated and dried.