JPS617698A - Method of producing multilayer circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to a method of manufacturing a multilayer wiring board for a hybrid IC.

(Prior Art) In general, multilayer wiring boards for hybrid ICs should have excellent heat dissipation properties, and for this reason, ceramics, which have excellent insulation and heat dissipation properties, have conventionally been used as substrates for such wiring boards. There is, and the manufacturing method is as follows.
A step of printing a conductive paint made of silver palladium on the ceramic substrate and sintering it to form a wiring circuit, and applying a paint made of low melting point glass on the wiring circuit and sintering it to form the wiring circuit. A multilayer wiring board is formed by repeating these steps a predetermined number of times.

(Problems to be Solved by the Invention) However, in the above manufacturing method, high-temperature treatment at, for example, 400 to 600 degrees Celsius is required for sintering the paint in each of the above steps, and equipment for performing the high-temperature treatment is required. Therefore, the manufacturing cost of the OIS printed wiring board was high.Also, as mentioned above, since ceramics are used as the substrate for the wiring board, which is difficult to obtain large and smooth ones, it is difficult to obtain large and smooth ones. It has been difficult to form a multilayer wiring board; (Means for solving the problem) However, in order to solve the above problems, the present invention aims to form a large and smooth substrate for a multilayer wiring board. In addition to using a metal plate that is easily available and much cheaper than ceramic, a metal foil is bonded to the metal board via an insulating adhesive resin layer. A step of forming a wiring circuit by applying an etching resist film on the metal foil and etching it, and connecting the lands of each wiring circuit to a sheet made by polymerizing the metal foil on an insulating adhesive resin layer. a step of adhering the sheet onto the wiring circuit formed on the substrate through the adhesive resin layer; and applying an etching resist film to the metal foil of the sheet and etching it. Wiring circuits are formed through processing.
This was done in order to manufacture a desired multilayer wiring board at low cost by the process of connecting each wiring circuit through the holes.

(Example ) The present invention will be explained in detail below.

First, a substrate (1) made of aluminum metal with a thickness of 1 mm with smooth lower surfaces is formed, and an uncured adhesive resin film (2) with excellent insulation effect is formed on the substrate (1). <Product name 5AF-40 manufactured by Nikkan Kogyo Co., Ltd.> was temporarily bonded. After layering a copper foil (3) with a thickness of 35μ on the film (2), air bubbles were removed and thermocompression bonded. By performing the above, the adhesive resin film (2) is cured,
As shown in Figure 1 (the copper foil (3) is
2) is bonded to the substrate (1)-L via the substrate (1)-L.

Then, an etching resist film is applied to the copper foil 2, and a predetermined wiring circuit (4) is formed as shown in FIG. 2 by a well-known etching process.

This completes step (A).

On the other hand, an uncured adhesive resin film (5) with excellent insulation properties similar to the above (trade name 5A manufactured by Ninokan Kogyo Co., Ltd.)
F-40>J A copper foil (6) with a thickness of 35 μm is also temporarily crimped to form a /-t (7).

Then, in the sorting (7), a wiring circuit (9) formed as described below and a wiring circuit (9) formed on the substrate (1) are formed.
Holes (8) for connecting with the sheet (4) are bored at predetermined positions in the sheet by drilling or pressing as shown in FIG.

With the above steps, the step (B) is completed.

Next, after overlapping the sheet (7) formed in the step (B) at a predetermined position of the wiring circuit (4) on the substrate (1), the resin film (7) of the film (7) is removed by removing air bubbles and thermocompression bonding. 5), the sheet (7), in other words, the copper foil (6) of the /-) (7) is cured, as shown in FIG. Fixed to.

Step (C) is completed by the following steps.

Then, an etching resist film is applied to the copper foil (6) of the sheet (7), and a predetermined wiring circuit (9) is formed as shown in FIG. 5 by the same etching process as described above.

With the above, step (D) is completed.

When a plurality of wiring circuits (4) and (9) are laminated on the board (1) J: as described above, finally the holes (8) are filled with solder as shown in FIG. (■0)
The wiring circuits (4) and (9) are connected at predetermined locations.

With the above, step (E) is completed.

(A) Sequentially from the process (B) (C) (D)
By performing the step (E), a multilayer wiring board including a predetermined number of wiring circuits can be formed.

Incidentally, in the above embodiment, a multilayer wiring board having two wiring circuits i, In this case, the sort formed separately in the step (B) is adhered to the wiring circuit (9) on the substrate (1) in the embodiment in the step (C), and the copper foil of the sort is coated with CC. ) After forming the third wiring circuit in step (D), step (E) may be performed in which each wiring circuit is connected through the hole between the two communicating holes.

Further, in the above embodiment, ゛ is 1 kg (10 kg) in step (E).
), the wiring circuits are connected through the holes, but the invention is not limited to this. For example, by filling the holes (8) with conductive resin and curing them, the conductive resin The respective wiring circuits may be connected via resin.

In the second embodiment, (A) → (B) → (C) → (D)
→ (E) Although the multilayer wiring board is manufactured in the order of the process, it is not limited to this. For example, (A) →
It may be manufactured in the order of steps (B) → (D), C) → (E).

Further, in the above embodiments, an aluminum plate was used as the substrate, but the substrate is not limited to this, and for example, a stainless steel plate or an iron plate may be used.

(Effects of the Invention) As described above, the multilayer wiring board manufactured by the manufacturing method of the present invention does not require sintering work that requires high temperatures as in the past, so the equipment investment cost is reduced accordingly, and the Since the substrate is a metal plate that is easily available, smooth and has excellent heat dissipation, it has become possible to provide a large multilayer wiring board suitable for hybrid ICs at a low cost.

[Brief explanation of drawings]

1 to 6 are schematic cross-sectional views at each step of a multilayer wiring board manufactured by the manufacturing method of the present invention. (1)...Substrate (2)...Adhesive resin layer (3)...Metal foil (4)...Wiring circuit (7)... ... Sort (8) ... Hall (9) ... Wiring circuit agent Patent attorney Tsu 1) Direct delivery box 1 Figure 5 Figure 4

Claims (1)

[Claims] A process of bonding a metal foil to a metal substrate via an insulating adhesive resin layer, and forming a wiring circuit by applying an etching resist film on the metal foil and performing an etching process (
A), a step (B) of drilling holes for connecting the lands of each wiring circuit in a sheet formed by polymerizing metal foil on an insulating adhesive resin layer, and forming the sheet on the substrate. a step of adhering onto the printed wiring circuit via the adhesive resin layer (
C) and the step of applying an etching resist film to the metal foil of the sheet and forming a wiring circuit by etching treatment (
A method for manufacturing a multilayer wiring board, comprising the steps of (D) and (E) connecting each wiring circuit through the holes.