JPH0699538A - Copper-plated laminated board and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a copper-plated laminated board and a method for manufacturing the same having small thermal expansion coefficient and excellent connecting reliability to a chip component. CONSTITUTION:A copper-plated laminated board is formed by arranging a flame sprayed ceramic layer 3 between a glass fiber-reinforced plastic layer 1 having 35wt.% or less of resin content and a copper foil 2. A method for manufacturing the board comprises the steps of forming the ceramic layer by flame spraying one side surface of the foil, so laminating a prepreg as to be brought into contact with the ceramic layer, and thermally press-molding it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper clad laminate used for printed wiring boards and a method for producing the same.

[0002]

2. Description of the Related Art Recently, as electronic devices have become smaller and higher in density, the electronic parts used are shifting from conventional leaded parts to chip parts. Therefore, the mounting method on a printed wiring board is also on the surface. The mounting method is becoming mainstream. Along with this, various requirements for copper-clad laminates used as printed wiring boards have become strict. That is, when the chip parts are surface-mounted on the printed wiring board,
From the viewpoint of connection reliability, matching of the coefficient of thermal expansion becomes a problem. However, the coefficient of thermal expansion of a fiber-reinforced plastic substrate such as a glass cloth-based epoxy resin copper-clad laminate that is widely used as a printed wiring board is considerably larger than that of a chip component. Therefore, when the chip components are surface-mounted, it is not possible to secure practically reliable connection reliability. In order to improve the connection reliability with chip components, a substrate with a thermal expansion coefficient closer to that of chip components,
That is, a substrate having a low coefficient of thermal expansion is needed.

[0003]

As a substrate material having a low coefficient of thermal expansion, a ceramic substrate such as alumina or aluminum nitride, which is different from the above organic substrates, or a low thermal expansion metal such as Invar or 42 alloy is used as a core. Previously used metal core substrates have been utilized. However, looking at these, because the ceramic substrate is very hard, it cannot be machined like drilling and cutting like the organic substrate,
There are drawbacks such as the inability to form a large-sized substrate, the complicated circuit processing and multi-layer process, and the high cost. Further, the metal core substrate having a low thermal expansion metal as a core has a drawback that it is heavy and cannot be reduced in weight, and it is necessary to provide an insulating coating in the hole of the metal core when forming the through hole. Therefore, development of a conventional organic substrate having a low coefficient of thermal expansion is desired.

As a low thermal expansion organic substrate, a substrate using a low thermal expansion base material such as aromatic polyamide fiber or quartz fiber has been developed for a long time, but it has a difficulty in machinability and cannot be put to practical use. I haven't arrived. Further, it is known that low resin differentiation is effective as a method for reducing the thermal expansion of the organic substrate, but voids are likely to occur inside the substrate due to the low resin differentiation, and the wet heat resistance decreases. I will end up. Therefore, conventionally, a substrate having a resin content of 35% by weight or less cannot be practically used. The present invention solves the above-mentioned problems, and based on an organic substrate, it can be handled in the same way as a conventional copper-clad laminate, and when a chip component is surface-mounted, it has excellent connection reliability. Provided is a laminated laminate and a method for producing the same.

[0005]

The present invention has a resin content of 35.
A copper clad laminate in which a thermal sprayed ceramic layer is placed between a glass fiber reinforced plastic layer of less than or equal to wt% and a copper foil, and a ceramic layer is formed by thermal spraying on one side of the copper foil, and a prepreg is laminated so as to contact the ceramic layer. The present invention relates to a method for manufacturing a copper clad laminate which is placed and thermocompression-molded.

The glass used for the glass fiber reinforced plastic layer may be E glass fiber which is widely used for general copper clad laminates, but the contents of SiO ₂ , Al ₂ O ₃ and MgO are different from each other. S glass fiber or T glass fiber having a content of 60% by weight or more, 20% by weight or more and 15% by weight or less, and a total of these three components being 97% by weight or more has a lower coefficient of thermal expansion than E glass fiber and is suitable. is there. The resin used for the glass fiber reinforced plastic layer is a thermosetting resin such as epoxy resin, polyimide resin, phenol resin, unsaturated polyester resin, vinyl ester resin, melamine resin or fluorine resin, polyethylene, polypropylene, polyether ether ketone. , Polysulfone,
A thermoplastic resin such as polyphenylene oxide is used. The reason why the resin content of the glass fiber reinforced plastic layer is 35% by weight or less is to reduce the thermal expansion of the glass fiber reinforced plastic layer due to the low resin differentiation.

The thermal sprayed ceramic layer provided between the glass fiber reinforced plastic layer and the copper foil is obtained by thermal spraying the ceramic on one surface of the copper foil by plasma spraying or gas spraying.
Then, a prepreg made of a glass fiber base material and a resin and a ceramic sprayed copper foil are laminated and placed so that the prepreg and the ceramic layer are in contact with each other, and thermocompression molding is performed to obtain a copper clad laminate. As the ceramic to be sprayed, an electrically insulating ceramic such as alumina, titania, zirconia, magnesia, mullite, spinel, zircon, cordierite, steatite, forsterite, and aluminum titanate can be used. Low cordierite is preferred. The thickness of the sprayed ceramic layer is not particularly limited, but is 25 to 300 μm.
Is preferred. If the thickness of the sprayed ceramic layer is thin,
The heat resistance during moisture absorption and the smoothness of the surface are lost, and the low thermal expansion effect of the sprayed ceramic layer is not exhibited. Further, if it is too thick, the machinability such as drilling workability is deteriorated. There is no limitation on the method of hot pressing.

[0008]

The sprayed ceramic layer covering the surface of the glass fiber reinforced plastic has pores of 5 to 20% by volume. Since the pores are sealed with resin, the resistance to moisture and heat is good and almost no water is absorbed. Absent. Therefore, almost no water can penetrate into the glass fiber reinforced plastic layer inside. Therefore, lower the resin content of the glass fiber reinforced plastic layer,
Even if voids are more likely to occur inside and the moisture and heat resistance is reduced, the moisture and heat resistance of the copper clad laminate after copper foil etching is equal to or more than that of the conventional laminate having a resin content of about 40% by weight. Become. Further, since the thermal sprayed ceramic layer has a low coefficient of thermal expansion, the thermal expansion coefficient of the glass-clad laminated board is reduced in combination with the thermal expansion coefficient of the glass fiber reinforced plastic layer.

[0009]

EXAMPLES Examples of the present invention will be described below. S glass with a thermal expansion coefficient of 2.5 × 10 ^-6 / ° C as glass fiber (S
A glass cloth (glass cloth WTA-116F, made by Nitto Boseki Co., Ltd., glass cloth WTA-116F) containing 65% by weight of iO _2, 23% by weight of Al ₂ O ₃ and 11% by weight of MgO and containing 99% by weight of the three components is impregnated with an epoxy resin. Then, a prepreg of a glass cloth base epoxy resin having an epoxy resin content of 25% by weight was prepared. Further, cordierite was sprayed on one surface of a 35 μm thick electrolytic copper foil (TSA-35 made by Furukawa Circuit Foil) by a Meteco 9MB type plasma spray gun to give a thickness of 150.
Two sheets with a layer of cordierite having a thickness of μm were prepared. Nine sheets of the above prepregs were stacked, and the ceramic sprayed copper foil was laminated on the press mold with the sprayed cordierite layers on both sides, and the temperature was 170 ° C and the pressure was 40 ° C.
Thermal compression molding under the condition of kgf / cm ² , and as shown in FIG. 1, the thickness of the glass cloth base material epoxy resin layer 1 with the thermal sprayed cordierite layer 3 in contact with the copper foil 2 on the outside. A 1.0 mm copper clad laminate was obtained. The thermal expansion coefficient of this copper clad laminate is 8.
It was 0 × 10 ⁻⁶ / ° C., which was almost equal to the coefficient of thermal expansion of the surface mount type chip part. Further, the copper foil of this copper-clad laminate is removed by etching, and a moisture absorption treatment (121
℃, 2 atm, in water vapor) and then 288 ℃ solder layer 2
As a result of soaking for 0 second, there was no abnormality at all.

As a comparative example, a copper clad laminate was obtained under the same conditions as in the above example except that no ceramic layer was provided. The coefficient of thermal expansion of this copper-clad laminate is 10 × 10 ⁻⁶ / ° C., which is the coefficient of thermal expansion of a glass cloth base material epoxy resin copper-clad laminate having a general resin content of 14 to 17 × 10 ⁻⁶ /. Although lower than ℃,
It does not reach that of the above-mentioned embodiment. Further, the copper foil of this copper-clad laminate was removed by etching, subjected to a moisture absorption treatment for 30 minutes (121 ° C., 2 atmospheric pressure, in steam), and then dipped in a solder layer at 288 ° C. for 20 seconds. Occurred.

[0011]

According to the present invention, a copper clad laminate having a smaller coefficient of thermal expansion than the conventional one can be obtained. Since this copper-clad laminate has a small difference in thermal expansion from the surface mounting chip component, it is possible to greatly improve the connection reliability when the chip component is mounted.

[Brief description of drawings]

FIG. 1 is a sectional view of a copper clad laminate according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Glass cloth base epoxy resin layer, 2 ... Copper foil, 3 ... Thermal sprayed cordierite layer

Claims (5)

[Claims] 1. A copper-clad laminate having a thermally sprayed ceramic layer between a glass fiber reinforced plastic layer having a resin content of 35% by weight or less and a copper foil. 2. The glass of the glass fiber reinforced plastic layer has a content of SiO ₂ , Al ₂ O ₃ and MgO of 60% by weight or more, 20% by weight or more and 15% by weight or less, respectively, and the total of these three components is The copper-clad laminate according to claim 1, which is 97% by weight or more. 3. The copper-clad laminate according to claim 1, wherein the resin of the glass fiber reinforced plastic layer is an epoxy resin. 4. The copper-clad laminate according to claim 1, wherein the ceramic of the thermal sprayed ceramic layer is mainly composed of cordierite. 5. A ceramic layer is formed on one surface of a copper foil by thermal spraying, and a prepreg is laminated and placed so as to be in contact with the ceramic layer and thermocompression-molded.
A method for producing the copper-clad laminate described.