JPH0448796A - Manufacture of multilayer interconnection board - Google Patents

Abstract

PURPOSE:To arrange that an inner-layer circuit is set to nearly the same plane as the surface of an inner-layer circuit board and to reduce that voids are produced by a method wherein the inner-layer circuit board is heated and pressurized, the inner-layer circuit is pushed into the surface of the inner-layer circuit board, an outer-layer circuit material is piled up, laminated and molded on the surface of the inner-layer circuit board via an adhesive layer. CONSTITUTION:An inner-layer circuit 1 is formed so as to protrude on the surface of an inner-layer circuit board 2. While the inner-layer circuit board 2 is being heated, it is pressed between pressurization rolls 11, 11 and the surface of the inner-layer circuit board 2 is pressurized. Thereby, the inner-layer circuit 1 is pushed into the surface part of the inner-layer circuit board 2 so as to be sunk into. The inner-layer circuit board 2 is heated to the glass transition temperature or higher of a resin; the inner-layer circuit 1 is pushed easily into the surface part of the inner-layer circuit board 2 and the surface of the inner- layer circuit 1 is set to the same plane as the surface of the inner-layer circuit board 2. When outer-layer circuit materials 4 are laminated, via adhesive layers 3, on the surface of the inner-layer circuit board 2, a multilayer interconnection board A is manufactured.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing a multilayer wiring board in which circuits are provided in multiple layers.

[Conventional technology]

The multilayer wiring board A is created by laminating an outer layer circuit material 4 on an inner layer circuit board 2. In other words, the inner layer circuit 1 is on the surface.
It is created by attaching an outer layer to the surface of an inner layer circuit board 2 with an adhesive layer 3 such as prepreg interposed therebetween. As the outer layer circuit material 4, an outer layer circuit board on which an outer layer circuit is formed, a metal tube such as a copper foil, or the like is used.

Problem to be Solved by the Invention 1 However, in the multilayer wiring board A produced in this way, since the inner layer circuit 1 is provided in a state protruding from the surface of the inner layer circuit board 2, the inner layer circuit board When the outer layer circuit material 4 is laminated on the inner layer circuit 1 through the adhesive layer 3, it is difficult to remove the air from the side surface of the inner layer circuit 1, and as shown in FIG. 4, this trapped air may cause voids 10. . When voids 10 occur in the multilayer wiring board A in this way, the voids 10 sometimes bulge during soldering and delamination (peeling) occurs, and when forming circuits on the outer layer circuit material 4, the plating liquid seeps into the board and the soldering process becomes difficult. This sometimes causes various problems such as electrolytic corrosion and deterioration of insulation performance. Such problems occur particularly frequently in continuous molding methods in which the outer layer circuit material 4 cannot be laminated with high pressure. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a multilayer wiring board that can reduce the occurrence of voids. [Means for Solving the Problems] A method for manufacturing a multilayer wiring board according to the present invention is to heat and pressurize an inner layer circuit board 2 on which an inner layer circuit 1 is formed. Push it into the surface,
Next, an outer layer circuit material 4 is stacked on the surface of this inner layer circuit board 2 via an adhesive layer 3, and lamination molding is performed.

[For use]

In the present invention, since the inner layer circuit 1 is pushed into the surface of the inner layer circuit board 2 by heating and pressurizing the inner layer circuit board 2, the inner layer circuit 1 is placed almost flush with the inner layer circuit board 2. In this state, the outer layer circuit material 4 can be laminated via the adhesive layer 3, and the outer layer circuit material 4 can be laminated with air trapped between the protruding side surface of the inner layer circuit 1 and the adhesive layer 3. This eliminates the need for lamination. K Example] The present invention will be described in detail below with reference to Examples. The inner layer circuit board 2 is made of, for example, epoxy on a base material such as glass cloth! Layering multiple sheets of prepreg prepared by impregnating and drying a thermosetting resin face such as M resin,
Layer metal foil such as copper foil on the outer surface of one or both sides,
It can be manufactured by laminating and molding this by heating and pressurizing it to create a laminate, and then etching the metal foil of this laminate to form the inner layer circuit 1. In this inner layer circuit board 2, the inner layer circuit 1 is provided so as to protrude from the surface of the inner layer circuit board 2. Next, this inner layer circuit board 2 is heated. The heating temperature is preferably set to a temperature higher than the glass transition temperature of the resin constituting the inner circuit board 2. Then, while heating the inner layer circuit board 2 as shown in FIG. By heating the inner layer circuit board 2 to a temperature higher than the positive transition temperature of the resin, the inner layer circuit 1 is easily pushed into the surface part of the inner layer circuit board 2, and the inner layer circuit 1 is pushed into the inner layer circuit board 2. The surface of the inner circuit board 2 can be made flush with the surface of the inner layer circuit board 2. In order to prevent the temperature required for heating from becoming too high, the resin constituting the inner layer circuit board 2 is preferably prepared so that its plus transition temperature is 120°C or lower, and the lamination molding conditions for the inner layer circuit board 2 are set to 130-140° C. ℃, 20-50 kg/cs
By setting the conditions to +2.20 to 40 minutes, it is possible to adjust the glass transition temperature to 120° C. or lower. Then, the heating temperature of the inner layer circuit board 2 is 140 to 150°C SS, and the pressing force when pushing the inner layer circuit 1 is 20 to 50°C.
kg/cm” range, the opening time is 5 to 10 minutes when pressurized.
! For pressurization, use a pressurizer 11 as shown in Fig. 1, or press the inner layer circuit board 2 between the plates and compress it with a normal press device. It can also be done by After the inner layer circuit 1 is pushed into the surface of the inner layer circuit board 2 to make it flush with the inner layer circuit 1 as described above, the outer layer circuit material 4 is laminated on the surface of the inner layer circuit board 2 with the adhesive layer 3 interposed therebetween. Plate A can be created. Here, adhesive layer 3
The same prepreg as described above can be used as the outer layer circuit material 4, and metal foil such as copper foil or an outer layer circuit board on which an outer layer circuit is formed in the same manner as the inner layer circuit board 2 can be used as the outer layer circuit material 4. can. In the embodiment shown in FIG. 2, a long strip-shaped prepreg is used as the adhesive layer 3, and a long strip-shaped metal foil is used as the outer layer circuit material 4, and the outer layer circuit material 4 is laminated by a continuous method. That is, while continuously feeding the adhesive layer 3 and the outer layer circuit material 4, the outer layer circuit material 4 is stacked on the surface of the inner layer circuit board 2 via the adhesive layer 3, and this is placed on the heated forming roll 12. By applying heat and pressure through
The outer layer circuit material 4 can be laminated onto the inner layer circuit board 2 via the adhesive layer 3 in a continuous flow. In this way, it is possible to obtain a multilayer wiring board A in which the outer layer circuit material 4 is laminated on the inner layer circuit board 2 as shown in FIG.
When a metal foil is used as the outer layer circuit material 4, finishing can be achieved by forming the outer layer circuit by processing such as etching to form the circuit. Here, since the inner layer circuit 1 is pushed in and is almost flush with the surface of the inner layer circuit board 2, the outer layer circuit material 4 is laminated.
This prevents the outer layer circuit material 4 from being laminated with air trapped between the side surface of the inner layer circuit 1 protruding from the surface of the inner layer circuit board 2 and the adhesive layer 3, and eliminates voids. This makes it possible to manufacture a multilayer wiring board A without any. In particular, when laminating the outer layer circuit material 4 using a continuous method as shown in Fig. 2, it is difficult to expel air and voids are likely to occur because large pressure cannot be applied. By laminating the outer layer circuit material 4 while keeping the surface of the board 2 flush, it is possible to eliminate voids even in a continuous construction method. By the way, in a multilayer wiring board manufactured by the conventional method, 1 to 3
The solder heat resistance test (D-2'100.
260°C, 301+) Conditions) e One-t'+ and delamination occurred, but in the multilayer wiring board manufactured by the method of the present invention, no voids were generated and no delamination occurred. .

【Effect of the invention】

As described above, in the present invention, the inner layer circuit is pushed into the surface of the inner layer circuit board by heating and pressurizing the inner layer circuit board, and then the outer layer circuit material is applied to the surface of the inner layer circuit board via an adhesive layer. Since the inner layer circuit is overlapped and laminated, the outer layer circuit material can be laminated via the adhesive layer while the inner layer circuit is almost flush with the surface of the inner layer circuit board, and the side surface of the protruding inner layer circuit can be bonded. The outer layer circuit material should not be laminated with air trapped between the layers (
This makes it possible to reduce the occurrence of voids.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the process of pressing the inner layer circuit according to an embodiment of the present invention, Fig. 2 is a schematic diagram showing the lamination process of the outer layer circuit material of the above, and Fig. 3 is a multilayer wiring board manufactured by the above. Figure $4 is a cross-sectional view of a conventional multilayer wiring board. 1 is an inner layer circuit, 2 is an inner layer circuit board, 3 is an adhesive layer, and 4 is an outer layer circuit material.

Claims (1)

[Claims] (1) Heating the inner layer circuit board with the inner layer circuit formed on the surface.
A method for producing a multilayer wiring board, characterized in that the inner layer circuit is pushed into the surface of the inner layer circuit board by applying pressure, and then the outer layer circuit material is stacked on the surface of the inner layer circuit board with an adhesive layer interposed therebetween for lamination molding.