JPH05218642A - Manufacture of circuit board - Google Patents

Abstract

PURPOSE:To improve the heat dissipating property of a circuit board by forming a first conductive layer onto a metallic base material through a first insulating layer, and sticking a second insulating layer and a second conductive layer at the same time onto the first conductive layer. CONSTITUTION:A first insulating layer 12 is made on a heat well conductive metallic base material 11, and first conductive layers 24 and 34 are made on this first insulating layer 12. Next, resin is applied between the patterns of these conductive layers 24 and 34 and on the edge 19 of the substrate 11 so as to remove the difference in level on the surface. This way, it is put in the condition that there is practically no difference in level, and a second insulating layer 20 and a second conductive layer 13 are made thereon. In that case, the second insulating layer 20 and the second conductive layer 13 are made in advance on the second insulating layer 20, and it is stuck onto the first conductive layers 23 and 34. Hereby, the heat dissipating property of the circuit board can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a circuit board based on a metal base material having a high heat dissipation property, which is suitable for mounting high heat generating components.

[0002]

2. Description of the Related Art Conventionally, a circuit board on which high heat-generating components are mounted has an insulating layer on a metal base material such as copper or aluminum as disclosed in JP-A-59-168696. A first copper foil pattern layer is formed on the metal base material, a desired portion of the metal base material is covered with an organic insulating material, and a copper clad insulation material having a through hole is aligned with the metal base material. Then, the through hole of the copper clad insulator is made conductive, and the surface layer of the copper clad insulator is etched to form a second copper foil pattern layer to form a two-layer metal base material. There is one that completes a circuit board.

[0003]

However, the above-mentioned conventional method is a copper clad insulation in which a first copper foil pattern layer is formed on a metal base material via an insulating layer and then through holes are formed. It is a manufacturing method that aligns and stacks the objects, conducts the through holes and performs etching on the surface layer of the copper clad insulator to form the second copper foil pattern layer, which complicates the process There is. Processing in each step other than through-hole drilling is processing on a metal base material, and it is difficult to carry and hold it due to its weight and rigidity. Furthermore, it is necessary to take measures such as protection of the metal base material against chemicals such as etching for forming the second copper foil pattern layer.

An object of the present invention is to solve the above problems and to provide a method for manufacturing a circuit board having a good heat dissipation by a simple manufacturing method.

[0005]

The present invention has the following means in order to achieve the above object.

As set forth in claim 1, a first conductive layer is formed on a metal substrate through a first insulating layer,
A method of manufacturing a circuit board is characterized in that a second insulating layer and a second conductive layer are simultaneously attached on the first conductive layer.

Further, as set forth in claim 2,
The second insulating layer is an insulator film having a window opening, the second conductive layer is a circuit pattern made of a conductor formed on the second conductive layer is a method for manufacturing a circuit board, characterized in that ..

[0008]

According to the first aspect of the present invention, a first conductive layer is formed on a metal substrate via a first insulating layer, and a second insulating layer is formed on the first conductive layer. By using the method of manufacturing a circuit board in which the layer and the second conductive layer are simultaneously attached,
Further, as described in claim 2, the second insulating layer is an insulator film having a window opening, and the second conductive layer is a circuit pattern made of a conductor formed thereon. According to the method of manufacturing a circuit board as described above, the process for forming the second conductive layer is performed on an insulating thin layer made of a resin such as epoxy resin, and a film-like lightweight work can be performed. Further, there is no problem such as the protection of the metal base material against the chemical solution by etching or the like, and the processing becomes simple.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to FIGS. In FIG. 1, 11 is a metal base material having good thermal conductivity such as copper or aluminum.
The first insulating layer 12 is formed on the metal base 11.
The first insulating layer 12 is, for example, epoxy resin or glass fiber impregnated with epoxy resin, and is formed by a coating method such as a roll coater or a flow coater, a screen printing method, or a sheet-like prepreg attaching method.

First conductive layers 24 and 34 made of copper or the like are formed on the first insulating layer 12. The method for forming the first conductive layers 24 and 34 is as follows: a method in which a copper foil is punched out in a pattern shape is attached, a method in which a copper foil is attached to the entire surface and etching is performed to form a pattern, 1 is subjected to electrolytic copper plating in a pattern as shown in FIG. 1 and then transferred or attached onto the first insulating layer 12. As the first conductive layers 24, 34, an arbitrary layer having a thickness of about 0.03 mm to about 3 mm can be manufactured by the above method. Among them, the thin copper is formed by the above-mentioned etching or electroplating method and transferring.

Thereafter, a resin is applied between the patterns of the conductive layer and the end portions of the substrate, that is, the portion 19 without the copper foil in FIG.
Try to eliminate the steps on the surface as much as possible. The resin material is the same epoxy resin as the first insulating layer 12. A dispenser or a screen printing method is used for coating. In this way, the second insulating layer 20 and the second conductive layer 13 are formed on the second insulating layer 20 with almost no step.

FIG. 3 shows an embodiment of forming the second insulating layer 20 and the second conductive layer 13. The second insulating layer 20 and the second conductive layer 13 are formed in advance on the insulator film (second insulating layer) 20 and attached onto the first conductive layers 24 and 34. As shown in FIG. 1, the insulating film (second insulating layer) 20 is provided with the second conductive layer 13 and window openings 54, 64, 74, 84. The circuit pattern of the second conductive layer 13 can be formed by etching a copper foil attached to the entire surface. In this case, since there is no metal base material, there is no need for special protection against etching chemicals.

When a semiconductor chip is bonded to such a circuit board, electroplating such as gold plating is performed on the land portion for bonding. The window opening parts 54, 64, 7
Gold plating is performed on the bonding land portions 4, 84 and the second conductive layer 13. That is, the plating resist is printed while leaving a portion where plating is desired to be performed, and electroplating is performed on the window-opened portion. When this electroplating is gold plating, precisely, after nickel plating, gold plating is performed again. After that, the plating resist can be removed to form a circuit board.

Next, mounting of high heat-generating components (semiconductor chips) on the circuit board manufactured in this way will be described.
The semiconductor chip is die-bonded to the gold-plated land portion of the first conductive layer. After this, wire bonding is performed starting from the die-bonded semiconductor chip and ending with the gold-plated land portion of the first conductive layer or the second conductive layer. The connection between the first conductive layer and the second conductive layer is made by wire bonding between the gold-plated lands.

FIG. 2 shows another embodiment of forming the first conductive layers 24 and 34. As shown in FIG. 2, the first conductive layers 24, 34 having a large thickness are formed by a method in which a punched copper plate is attached to the first insulating layer 12. In FIG. 2, reference numeral 118 is a portion that will eventually become an external terminal. Then, as in the first embodiment, the second conductive layer 13 formed on the insulating film (second insulating layer) 20 is attached onto the first conductive layers 24 and 34.

Next, another embodiment will be described. Figure 4
11 is a metal base material having good heat conductivity such as copper or aluminum. The first insulating layer 1 is formed on the metal base material 11.
Form 2. The forming method is a screen printing method, and the material is an epoxy resin. During the printing of the first insulating layer 12, the window opening portion 44 partially having no insulating layer is formed.

A first conductive layer 34 made of copper or the like is formed on the first insulating layer 12. The forming method is the same as the forming method of the first conductive layers 24 and 34 of FIG. After that, resin is applied between the patterns of the conductive layer and the end portion of the substrate, that is, the portion 19 without the copper foil in FIG. 4, so as to eliminate the surface step as much as possible. The resin material is an epoxy resin like the first insulating layer 12. A dispenser or a screen printing method is used for coating. In this way, there is almost no step.

In this case, the second insulating layer (film) and the second conductive layer are formed by the method as described above and attached on the first conductive layers 24 and 34. The window opening portions 54, 64, 74, 84 are formed so that the metal substrate 11 or the first conductive layer 34 is partially exposed at the window opening portion provided in the second insulating layer (film). To be done. Therefore, FIG.
In the case where the second insulating layer and the second conductive layer are formed on the substrate, the structure is such that the metal base material 11 or the first conductive layer 34 is exposed.

After that, electroplating such as gold plating is performed on the bonding land portion to which the semiconductor chip or the like is bonded. Therefore, the land portion of this bonding partially includes the window opening portion 44 without the first insulating layer, the window opening portions 54, 64, 74, 84 of the second insulating layer and the second conductive layer 13.
It becomes a land portion for the upper bonding, and the die bonding of the semiconductor chip can be performed on the metal base material 11 and the first conductive layer. If necessary, the semiconductor chip can be die-bonded on the second conductive layer 13 as well.

[0020]

[Effects of the Invention] With the above-mentioned structure, the following effects can be obtained.

As described in claim 1, a first conductive layer is formed on a metal substrate via a first insulating layer,
By using the method for manufacturing a circuit board in which the second insulating layer and the second conductive layer are simultaneously attached on the first conductive layer, as described in claim 2, The second insulating layer is an insulator film having a window opening portion, and the second conductive layer is a circuit pattern made of a conductor formed on the second conductive layer. The conductive layer is formed on the insulating thin layer made of a resin such as an epoxy resin, so that a film-like and lightweight process can be performed. Further, there is no problem such as the protection of the metal base material against the chemical solution by etching or the like, and the processing becomes simple.

[Brief description of drawings]

FIG. 1 is a perspective view showing a step of forming a first conductive layer in a method for manufacturing a circuit board according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing another method of forming the first conductive layer according to another embodiment of the present invention.

FIG. 3 shows a state before the second insulating layer and the second conductive layer are attached onto the circuit board having the first conductive layer formed by the method for manufacturing the circuit board according to the first embodiment of the present invention. It is a perspective view showing.

FIG. 4 is a perspective view showing a step of forming a first conductive layer in a method for manufacturing a circuit board according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Metal base material 12 1st insulating layer 13 2nd conductive layer 20 2nd insulating layer (insulator film) 24 1st conductive layer 34 1st conductive layer 44 Window opening part of 1st insulating layer 54 second insulating layer window opening portion 64 second insulating layer window opening portion 74 second insulating layer window opening portion 84 second insulating layer window opening portion

Claims (2)

[Claims] 1. A first conductive layer is formed on a metal substrate via a first insulating layer, and a second insulating layer and a second conductive layer are simultaneously formed on the first conductive layer. A method for manufacturing a circuit board, which comprises attaching the circuit board. 2. The second insulating layer is an insulating film having a window opening, and the second conductive layer is a circuit pattern made of a conductive material formed thereon. 2. A method for manufacturing a circuit board as set forth in claim 1.