JPH06204632A - Copper-clad laminated board for surface mounting printed wiring board - Google Patents

Abstract

PURPOSE:To prevent the generation of cracks caused by thermal shock at the solder connecting part of a surface mounting part with a copper-clad laminated board for a surface mounting printed wiring board. CONSTITUTION:In an epoxy resin laminated board of glass woven fiber base material, a layer of butyral denaturation phenol resin is formed in the inside of a copper foil as a unitary body at the surface in contact with the copper foil. The layer becomes a rubber state at a high temperature. Stress based on the difference in thermal expansions of the surface mounting part and a substrate is absorbed, and the generation of cracks caused by the above described stress at a solder connecting part is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to surface mount components (Sur
The present invention relates to a copper-clad laminate for a printed wiring board for mounting a face mount device (SMD).

[0002]

2. Description of the Related Art A printed wiring board on which an SMD such as a ceramic chip is mounted has a coefficient of thermal expansion of 6.5 × 10 to SMD.
^Since it is as small as ⁶ / ° C, a substrate for a wiring board is also required to have a small coefficient of thermal expansion in the plane direction. Conventionally used is a glass woven fabric-based epoxy resin laminate (FR-
4) the is obtained by a substrate, the thermal expansion coefficient of the plane direction is ^{(10~15) × 10 ~ 6 /} ℃. A reflow soldering method using cream solder is mainly used for mounting the SMD.

[0003]

In the above technique, the SM is used.
Since the difference in the coefficient of thermal expansion between D and the substrate is relatively small, the difference in the expansion and contraction due to the heat of the two is not so large.
Currently supported. However, when the thermal shock increases, the difference between the expansion and contraction also increases, and a large stress acts on the solder connection portion, so that cracks are likely to occur in the solder connection portion. The problem to be solved by the present invention is to improve the connection reliability against the thermal shock of the solder connection part of the printed wiring board on which the SMD is mounted, and to provide a copper clad laminate for that purpose.

[0004]

A copper-clad laminate for a surface-mounting printed wiring board according to the present invention which solves the above-mentioned problems has an epoxy resin-impregnated glass woven base material layer as a substrate and a copper foil integrally formed on the surface thereof. The provided one is characterized in that a layer of butyral-modified phenolic resin was formed inside the copper foil in contact with it.

[0005]

The above-mentioned butyral-modified phenol resin layer has 1 layer.
The elastic modulus at 00 ° C. is 40 Kgf / cm ² , which is considered to be almost rubbery. Therefore, even if the use environment becomes high and the difference in thermal expansion between the substrate and the mounted SMD becomes large, the layer of butyral-modified phenolic resin in the rubber state is deformed, and the heat It is possible to absorb the stress due to the difference in expansion and avoid applying stress to the solder connection portion.

[0006]

Example 1 Eight prepregs obtained by impregnating a 0.2 mm-thick glass woven cloth with a brominated bisphenol A type epoxy resin and drying the prepregs were laminated with a 25 μ-thick butyral-modified phenolic resin sheet on both sides. Then, a copper foil of 18 μm was placed on the outermost layer, and heat and pressure molding was performed at a temperature of 165 ° C. and a pressure of 30 Kgf / cm ² for 50 minutes to obtain a 1.6 mm thick copper clad laminate. Wiring board processing was performed on this laminated board in the following steps. After the through hole processing at a predetermined position, a circuit was formed by etching, and a solder leveler process was performed as a final finish. In the component mounting and soldering process, a ceramic chip resistor (4532 type) was mounted on the reflow surface and the flow surface, far infrared reflow soldering (cream solder) was performed, and then flow soldering (molten solder) was performed. After observing the initial surface condition of the solder joint, -30 ℃ / 30 minutes and 80 ℃
A vapor phase cooling / heating cycle test was performed for / 30 minutes, and the occurrence of cracks at the solder joints was observed. The results are shown in Table 2 together with other properties. In Table 1, the elastic moduli of the substrate and the butyral-modified phenolic resin layer are shown for reference. The butyral modified phenolic resin layer is about 1 / th of the substrate even at 30 ° C.
The elastic modulus is 5.

The butyral modified phenolic resin layer is
Instead of using the sheet, a butyral-modified phenolic resin may be applied to the adhesive surface of the copper foil or the prepreg on the surface.

[0008]

[Table 1]

Conventional Example 1 In Example 1, a butyral-modified phenolic resin sheet was not used, and the other steps were the same as in Example 1 to obtain a wiring board. The characteristics are shown in Table 2.

[0010]

[Table 2]

In Table 2, the through hole reliability is 20
By repeating the dipping in the silicone oil of ° C and the silicone oil of 260 ° C, the cycle until the increase of the conduction resistance occurred was examined. The solder heat resistance was measured by immersing in a solder bath at 260 ° C. Insulation resistance is a comb pattern (pitch 0.5 mm,
Line width 0.5mm), C-1000 / 80 /
After 95 treatment, 100 V was applied for 1 minute and then measured.

[0012]

As is apparent from Table 1, the butyral-modified phenolic resin layer absorbs the stress caused by the difference in thermal expansion between the substrate and the surface-mounted component, and cracks due to the stress are generated in the solder joint. Can be prevented.
And other characteristics are the same as the conventional glass woven fabric-based epoxy resin laminate.

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[Procedure amendment]

[Submission date] June 24, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

Example 1 Eight prepregs obtained by impregnating a 0.2 mm-thick glass woven cloth with a brominated bisphenol A type epoxy resin and drying the prepregs were laminated with a 25 μ-thick butyral-modified phenolic resin sheet on both sides. Then, a copper foil of 18 μm was placed on the outermost layer, and heat and pressure molding was performed at a temperature of 165 ° C. and a pressure of 30 Kgf / cm ² for 50 minutes to obtain a 1.6 mm thick copper clad laminate. Wiring board processing was performed on this laminated board in the following steps. After the through hole processing at a predetermined position, a circuit was formed by etching, and a solder leveler process was performed as a final finish. In the component mounting and soldering process, a ceramic chip resistor (4532 type) was mounted on the reflow surface and the flow surface, far infrared reflow soldering (cream solder) was performed, and then flow soldering (molten solder) was performed. After observing the initial surface condition of the solder joint, -30 ℃ / 30 minutes and 80 ℃
A vapor phase cooling / heating cycle test was performed for / 30 minutes, and the occurrence of cracks at the solder joints was observed. The results are shown in Table 2 together with other properties. In Table 1, the elastic moduli of the substrate and the butyral-modified phenolic resin layer are shown for reference. The butyral modified phenolic resin layer is about 1 / th of the substrate even at 30 ° C.
5, which is a 00 modulus of elasticity.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[Table 1]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

As is clear from Table 2 , the butyral-modified phenolic resin layer absorbs the stress caused by the difference in thermal expansion between the substrate and the surface-mounted component, and the solder joint is cracked due to the stress. Can be prevented.
And other characteristics are the same as the conventional glass woven fabric-based epoxy resin laminate.

[Procedure amendment]

[Submission date] March 1, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

Example 1 Eight prepregs obtained by impregnating a 0.2 mm-thick glass woven cloth with a brominated bisphenol A type epoxy resin and drying the prepregs were laminated with a 25 μ-thick butyral-modified phenolic resin sheet on both sides. Then, a copper foil of 18 μm was placed on the outermost layer, and heat and pressure molding was performed at a temperature of 165 ° C. and a pressure of 30 Kgf / cm ² for 50 minutes to obtain a 1.6 mm thick copper clad laminate. Wiring board processing was performed on this laminated board in the following steps. After the through hole processing at a predetermined position, a circuit was formed by etching, and a solder leveler process was performed as a final finish. In the component mounting and soldering steps, a ceramic chip resistor (4532 type) was mounted on the reflow surface and the flow surface, far infrared reflow soldering (cream solder) was performed, and then flow soldering (molten solder) was performed. After observing the initial surface condition of the solder joint, -30 ℃ / 30 minutes and 80 ℃
A vapor phase cooling / heating cycle test was performed for / 30 minutes, and the occurrence of cracks at the solder joints was observed. The results are shown in Table 2 together with other properties. In Table 1, the elastic moduli of the substrate and the butyral-modified phenolic resin layer are shown for reference. The butyral modified phenolic resin layer is about 1 / th of the substrate even at 30 ° C.
5, which is a 00 modulus of elasticity.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

[Table 1]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

As is clear from Table 2 , the butyral-modified phenolic resin layer absorbs the stress caused by the difference in thermal expansion between the substrate and the surface-mounted component, and the solder joint is cracked due to the stress. Can be prevented.
And other characteristics are the same as the conventional glass woven fabric-based epoxy resin laminate.

Claims (1)

[Claims] 1. A copper-clad laminate having an epoxy resin-impregnated glass woven base material layer as a substrate, and a copper foil integrally provided on the surface thereof, wherein a butyral-modified phenolic resin layer is provided inside the copper foil and in contact therewith. The formed copper-clad laminate for surface-mounted printed wiring boards.