JPH07201894A - Manufacture of electronic parts mounting device - Google Patents

Abstract

PURPOSE:To simplify the soldering of device leads to a conductor circuit of a semiconductor chip mounting board. CONSTITUTION:A bonding agent layer 13 is provided at the position near the external circumference of a wiring substrate 10. A solder paste 14 is provided by the printing method at the external end portion of a conductor circuit of the wiring substrate. An inner lead is fixed to the bonding agent layer under the condition that the end point of the inner lead 21 of a lead frame 20 is arranged on the external end portion of the conductor circuit. A heating tool 30 is deposited with pressure to the inner lead of the bonding agent layer and solder. With softening of the bonding agent layer and melting of solder, the inner lead is rigidly bonded to the wiring substrate with the bonding agent layer and is simultaneously fixed to the conductor circuit with the solder. A thermal stress after the bonding is dispersed to the bonding agent layer and solder, enhancing reliability of the bonding area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electronic component mounting device, and more particularly to a method for manufacturing an electronic component mounting device in which a conductor circuit of a wiring board and a lead frame are connected by solder.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing an electronic component mounting apparatus of this type has been described in Japanese Unexamined Patent Publication No. 3-203357, in which a lead provided with a high lead solder ball is provided in a hole provided at the tip. By aligning with the through hole of the wiring board and performing reflow, the solder is filled in the through hole and the lead tip hole is filled with solder to form a solder joint between the lead and the through hole. Then, the solder joint portion is fixed and protected by a reinforcing agent.

[0003]

However, according to the above-described manufacturing method, the lead is only aligned with the wiring board and is not fixed to the wiring board. Therefore, the thermal stress generated when the solder is returned from the heated state to room temperature is concentrated on the solder joint portion between the lead and the through hole, which may reduce the reliability of the solder joint portion. Further, it takes work time to provide the solder balls on the leads, and the material cost becomes expensive. Furthermore, after positioning the leads with solder balls on the wiring board, a reflow process for melting the solder balls is required, and then a step of providing a reinforcing agent on the solder joints is also required, which greatly reduces the manufacturing time. There is a problem that it becomes long and the final electronic component mounting apparatus becomes expensive. The present invention is intended to solve the above problems, and an electronic component mounting apparatus that can perform solder bonding between a lead and a conductor circuit of a wiring board by a simple method at low cost and has excellent connection reliability. It is intended to provide a manufacturing method.

[0004]

In order to achieve the above object, the structural feature of the invention according to claim 1 is that the outer periphery of a wiring board is provided with a plurality of conductor circuits that spread toward the outer periphery on the surface side. The step of providing an adhesive layer in the vicinity of the area, the step of applying paste-like solder to the outer end of the conductor circuit, and the placement of at least the tip portions of the leads of the lead frame on the outer end of the conductor circuit. In this state, a step of adhering the lead frame to the adhesive layer and a step of heating and pressing the lead frame with a heating jig at the solder and adhesive layer positions are provided.

[0005]

In the invention according to claim 1 configured as described above, when the heating jig is pressure-bonded to the lead frame, the adhesive layer is simultaneously softened by heating and pressurizing and the paste-like solder is melted. Further, the lead frame is strongly pressed against the adhesive layer and the molten solder by the pressure applied by the heating jig, and is firmly adhered to the wiring board. The thermal stress generated when the heating jig is removed and the wiring board is returned to room temperature is distributed not only to the solder joints between the lead frame and the conductor circuit but also to the leads and wiring board through the adhesive. To be done.

[0006]

As a result, the stress applied to the solder joint is reduced, and the reliability of the joint between the lead and the conductor circuit is improved. Also, the lead frame brought into contact with the adhesive layer and the solder can be reinforced by the adhesive layer of the lead frame and connected to the conductor circuit at the same time by a simple operation of simply crimping the heating jig, The manufacturing process of the electronic component mounting device can be significantly shortened, and the product can be provided at low cost.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged perspective view showing a part of a semiconductor chip mounting device according to an embodiment. FIG. 2 is a cross-sectional view schematically showing a main part of a manufacturing process of a semiconductor chip mounting device. The wiring board 10 is provided with a plurality of conductor circuits 11 obtained by subjecting a surface of a base material such as glass epoxy to which a copper foil is adhered to by photoetching, and a semiconductor chip formed by punching at the center. An opening 12 for mounting is provided. Further, on the back surface side of the wiring board 10, a heat dissipation plate 30 made of oxygen-free copper, which also serves as a semiconductor chip attachment, is bonded and fixed with an adhesive 31 such as epoxy in a state of covering the opening 12. An epoxy adhesive is applied by screen printing, a dispenser or the like to a position near the outer periphery on the front surface side of the wiring board 10 to provide an adhesive layer 13 (see FIG. 2A). It should be noted that the adhesive may be polyimide or the like as long as it has excellent heat resistance and insulating properties, and is not limited to a liquid form, and may be a B-stage sheet form. In the case of a sheet, a punched adhesive sheet may be attached to the wiring board 10a, or may be temporarily adhered to a lead frame 20 described later.

Next, a solder paste is applied to the outer end portion of the conductor circuit 11 of the wiring board 10 by a screen printing method or the like and dried to provide a solder layer 14 (see FIG. 2B). Then, the lead frame 20 is attached to the inner lead 2
The tip of 1 is positioned on the outer end of the conductor circuit 11 and fixed to the adhesive layer 13 by temporary adhesion (FIG. 2).
(See (c)). Further, the adhesive layer 13 and the solder layer 14
A heating tool 30 heated to, for example, 230 ° C. is pressed against the upper inner lead 21 (see FIG. 2C). As a result, the inner lead 21 is heated and pressed, and at the same time, the adhesive layer 13 is softened and the solder paste 14 is melted. Then, the inner lead 21 is strongly pressed against the adhesive layer 13 and the molten solder layer 14 by the pressure of the heating tool 30. Therefore, it is possible to reinforce the inner lead 21 with the adhesive layer 13 at the same time as connecting the inner lead 21 and the conductor circuit 11. In addition, this work is performed on the lead frame that is in contact with the adhesive layer and the solder.
Since this is a simple operation of only pressing the heating tool 30, the manufacturing process of the semiconductor chip mounting device can be significantly shortened, and the product can be provided at low cost. Further, the thermal stress generated when the heating tool 30 is removed and the wiring board is returned to room temperature is not only the solder joint between the lead frame 20 and the conductor circuit 11, but also the inner lead 21 and the wiring board 10 through the adhesive layer 13. It is also dispersed in the part of. As a result, the stress applied to the solder joint is reduced, and the reliability of the joint between the inner lead 21 and the conductor circuit 11 is improved.

The semiconductor chip S is die-bonded onto the heat dissipation plate 30 in the opening 12 of the semiconductor chip mounting device using silver paste or the like, and the electrode pads of the semiconductor chip S and the conductor circuit 12 of the wiring board 10 or The inner leads 21 are connected by wire bonding. Further, it is molded with epoxy resin R or the like, and the lead frame 20 is cut to form a final semiconductor device (see FIG. 3).

In the above embodiment, the semiconductor chip mounting device in which the semiconductor chip is mounted on the wiring board has been described, but other electronic parts may be mounted. A plurality of semiconductor chips may be mounted on the semiconductor chip mounting device. Further, the semiconductor chip mounting device may not be provided with a heat dissipation plate if necessary. In that case, the semiconductor chip is directly mounted on the wiring board.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a part of a semiconductor chip mounting device according to an embodiment of the present invention.

FIG. 2 is a cross sectional view schematically showing a part of the manufacturing process of the semiconductor chip mounting device.

FIG. 3 is a sectional view schematically showing a completed state of a semiconductor device using the same semiconductor chip mounting device.

[Explanation of symbols]

10: wiring board, 11: conductor circuit, 12: opening, 1
3; adhesive layer, 14; solder layer, 20; lead frame, 21; inner lead, 30; heat sink, S; semiconductor chip, R; mold resin.

Claims (1)

[Claims] 1. A step of providing an adhesive layer in the vicinity of the outer periphery of a wiring board having a plurality of conductor circuits spread on the surface side toward the outer periphery, and applying paste-like solder to the outer end of the conductor circuit. And a step of adhering the lead frame to the adhesive layer in a state where at least tip portions of the plurality of leads of the lead frame are arranged on an outer end portion of the conductor circuit, the solder and the adhesive layer And a step of heating and pressing the lead frame with a heating jig at a position.