JPS62120035A - Manufacture of resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To improve a discharge resistance by covering the back surface and the front exposed portion of a substrate support with the first resin and the second resin having good bondability with a lead frame to eliminate a swelling phenomenon. CONSTITUTION:The back surface and the front exposed surface 6 of a substrate support 3 are covered with the first resin and the second resin having good bondability with a lead frame. The first resin uses, for example, epoxy resin, and the second resin 7 uses polyimide resin. Since the second resin 7 has good bondability with the first resin 5 and the lead frame 2, even if the lead frame is, for example, oxidized, the bondability is improved to eliminate a swelling phenomenon. Since the exposed surface 6 of the support 3 is covered with the resin 7, a discharge resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of manufacturing a high-power resin-encapsulated semiconductor device that generates heat.

(b) Conventional technology In general, semiconductor devices are superior to other semiconductor devices in terms of product processability, mass production, cost, etc., but are inferior in terms of heat dissipation. However, in recent years, high-power semiconductor devices with a large amount of resin encapsulation have been devised, such as those disclosed in Japanese Patent Laid-Open No. 180127/1983.

The lead frame has three external leads extending in the same direction on a common strip. The central external lead is connected to a substrate support that also serves as a heat sink. Furthermore, the external leads at both ends are longer than the common strip, and the terminal end has a slightly wider area so that bonding work can be carried out efficiently. The substrate support (2) has a semiconductor pellet attached to its slightly lower central portion, and a through hole (4) for fixing a heat dissipating plate to a cleaning hole in its upper central portion. Further, the external leads are selected to be thinner than the substrate support (c) so that they can be easily cut, and a step is provided between the external leads and the substrate support to facilitate bonding.

Prepare the lead frame as described above and attach the semiconductor element (
Fix c) with solder, etc. Then wire bonds are made to electrically connect.

Next, the lead frame @ is held between the upper and lower molds.

Two pairs of protruding clamping bodies are formed on each of the upper and lower molds, and when the upper and lower molds are combined, they form a V-shaped clamping body. A part of the inner taper of this square-shaped holding body is in contact with a corner of one end of the substrate support.

Thereafter, resin was injected into the mold to achieve a resin sealing amount of the semiconductor device ■υ.

(c) Problems to be Solved by the Invention However, in the above manufacturing method, if the back surface of the substrate support is oxidized, the adhesion of the resin will deteriorate and the resin formed on the back surface of the substrate support will deteriorate. A phenomenon occurred.

In addition, the resin is not sealed in the part corresponding to the sandwiching body in the square square shape, and the substrate support (2) is exposed in the air, which causes a problem in that the discharge withstand voltage decreases.

B) Means for Solving the Problems The present invention has been made in view of the problems of soil expansion.
The process of preparing a frame (2) and the lead frame (2)
) A step of floating the substrate support (3), which is a part of the substrate support (3), with a pair of protruding clamps formed in the mold so that the back surface of the substrate support (3) can also be sealed with resin; In the method of manufacturing a semiconductor device with a resin sealing amount, the first resin (5) and the lead resin are injected into at least the back surface and the surface exposed portion (6) of the substrate support (3). This problem can be solved by including a step of coating the frame (2) with a second resin (7) that has good adhesion.

(e) Function The present invention provides a second resin (7) that is in close contact with the first resin (5) and the lead frame (2) at least on the back surface and surface exposed portion (6) of the substrate support (3). ), the lead frame (2) and the first resin (5
) has good adhesion and can eliminate the blistering phenomenon.

Furthermore, since the surface exposed portion (6) of the substrate support (3) is coated with the second resin (7), the substrate support (3) is not directly exposed to the air (this improves the discharge withstand voltage). .

(F) Embodiment An embodiment of the present invention will be described below with reference to FIG. First, a copper-based material with good thermal conductivity is used as the material for the lead frame (2), and is processed by pressing, photo-etching, or the like. Furthermore, the lead frame (2) is made of Au, Ag, and Ni to improve chip mounting performance, bonding performance, lead corrosion resistance, and solderability.
, Sn, etc. are plated.

The lead frame (2) as described above has three external leads extending in the same direction in one common strip, and the central external lead is connected to the substrate support (3) which also serves as a heat sink. Furthermore, the external leads at both ends are longer than the common strip, and the terminal end has a slightly wider area so that bonding work can be carried out efficiently. The substrate support (3) is a semiconductor pellet (4).
) is attached at the slightly lower center, and a through hole (8) for fixing a screw for fixing the heat sink is attached at the upper center. Further, the external leads are selected to be thinner than the substrate support (3) so that they can be easily cut, and a step is provided between the external leads and the substrate support (3) to facilitate bonding.

A lead frame (2) as described above is prepared, and then a semiconductor element (4) is fixed with solder or the like. Connect it electrically by wire bonding with A [wire etc.

Next, at least the back surface and exposed surface portion (6) of the substrate support (3) are coated with the first resin (5) and a second resin (7) that has good adhesion to the lead frame (2).

This step is a feature of the present invention. For example, the first resin (5) uses an epoxy resin, and the second resin (7)
uses polyimide resin. This second resin (7) has good adhesion with the first resin (5) and the lead frame (2), so even if the lead frame (2) is oxidized, for example, the adhesion between them is good. It can eliminate the phenomenon of swelling. In addition, the substrate support (3) after resin molding
) is also coated with the second resin (7), so that the discharge withstand voltage is improved. Here, FIG. 1 shows a state in which the second resin (7) is coated, for example, by dipping.

Next, the lead frame (2) is held between the upper mold and the lower mold, and two pairs of protruding clamping bodies are provided on parts of the upper mold and the lower mold. When the upper mold and lower mold are brought together, a V-shaped clamping body is formed. A portion of the inner taper of this V-shaped clamp contacts the corner of the end of the substrate support (3). Therefore, it becomes possible to float the substrate support (3) and inject resin into the back surface.

Finally, resin is injected from the external lead side or the substrate support (3) side, and when the resin hardens, the lead frame is cut to form a resin-sealed semiconductor element (1).

(G) Effects of the Invention As is clear from the above description, the present invention provides the first resin (5) and the lead frame (2) at least on the back surface and surface exposed portion (6) of the substrate support (3). ) and the second resin (7) which has good adhesion, the adhesion between them becomes good and the blistering phenomenon can be eliminated. Resin (7
) is coated, so the discharge withstand voltage is improved. Therefore, reliability is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device manufactured by a method for manufacturing a resin-filled semiconductor device according to an embodiment of the present invention, FIG. 2 is a plan view of the resin-filled semiconductor device in FIG. 1, and FIG. The figure is a cross-sectional view of a semiconductor device manufactured by a conventional manufacturing method. Explanation of the main drawing numbers: (1) is the resin sealing amount semiconductor device, (2) is the lead frame, (3) is the substrate support, (4) is the semiconductor element, (5) is the first resin, ( 6) is the surface exposed part, (7
) is the second resin, and (8) is the through hole.

Claims (1)

[Claims] (1) A process of preparing a lead frame to which at least an electrically connected semiconductor element is fixed, and forming it into a mold so that the back side of the substrate support, which is a part of the lead frame, can also be sealed with resin. In the method for manufacturing a semiconductor device with a resin sealing amount, the method includes the steps of floating a first resin with a pair of protruding holders, and injecting a first resin into the mold. The first
1. A method for manufacturing a resin-sealed semiconductor device, comprising the step of coating the resin and a second resin that has good adhesion to the lead frame.