JP2505068Y2 - Package structure of semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a semiconductor device package structure for modules such as power transistors and thyristors.

[Conventional technology]

First, FIG. 3 shows the structure of a semiconductor device to which the present invention is applied. In the figure, 1 is a semiconductor element, 2 is a substrate on which the semiconductor element 1 is mounted, 3 is an external lead terminal, 4 is a package incorporating these components, and 5 is a package 4.
Gel-like silicone resin filled inside to seal the semiconductor element 1 is epoxy resin injected into the upper portion.
Here, the package 4 is a metal base 7 that also functions as a heat sink.
And a case frame 8 made as a resin molded product and a case lid 9 are combined. As shown in FIG. 4, a stepped groove 8a is formed along the inner peripheral edge on the lower end side of the case frame 8 and the outer peripheral edge of the metal base 7 is fitted into the stepped groove 8a. is there.

Such a semiconductor device is assembled as described below.
First, the substrate 2 to which the semiconductor element 1 is die-bonded is adhered onto the metal base 7, and then an internal lead is provided between the external lead-out terminal 3 mounted on the case lid 9 and the conductor pattern of the semiconductor element 1 and the substrate 2. Solder through. Next, after covering the metal base 7 with the case frame 8 and adhering the two with the adhesive 10, the gel silicone resin 5 is filled in the case, and the epoxy resin 6 is injected and cured on the upper layer side. And resin sealing.

Here, in order to bond the case frame 8 to the metal base 7,
The synthetic resin adhesive 10 supplied from a dispenser in advance along the peripheral area of the joint surface of the case frame 8 is linearly applied and applied, and the case frame 8 is superposed on the metal base 7 and a pressing force is applied. Then, the adhesive is spread over the joint surface and held in this state to cure the adhesive.

[Problems to be solved by the device]

By the way, in the package assembled by the above method, the gel-like sealing resin filled in the package may leak to the outside through the gap between the metal base and the case frame due to defective bonding. On the other hand, if the adhesive is applied in a slightly larger amount in order to avoid such a bonding failure, conversely, when a pressure is applied in the bonding process, the excess adhesive protrudes from the bonding surface to the outer peripheral side of the package. In particular, as shown in FIG. 4, in the structure having the stepped groove 8a, since there is a joint with the outer peripheral edge of the metal base, the adhesive at the joint has a pressure force and a capillary phenomenon in the bonding step. Further, since gravity also acts, excess adhesive tends to protrude from the joint surface to the outer peripheral side of the package as compared with the structure shown in FIG. In addition, the adhesive protruding to the outer periphery requires a manual work of wiping off the adhesive, which increases the number of assembly steps.

The present invention has been made in view of the above points, and provides a package structure of a semiconductor device in which a metal base and a case frame can be firmly bonded to each other while avoiding poor adhesion, adhesive protrusion, and the like. The purpose is to

[Means for solving the problem]

In order to solve the above-mentioned problems, in the package structure of the present invention, an adhesive agent is provided so as to face the main surface of the metal base over the entire circumference of the bonding surface of the case to be bonded to the metal base whose both main surfaces are flat. A concave groove serving as a reservoir and a convex step portion that is spaced apart from the concave groove and fits on the outer peripheral edge of the metal base are provided.

[Action]

With the above configuration, after the adhesive is supplied and applied to the joint surface, when the case and the metal base are overlapped and a pressure is applied, the adhesive is spread over the entire joint surface, and the surplus adhesive is It enters the recess and collects here. Moreover, since the concave groove is opposed to the main surface of the metal base and sucks the surplus adhesive agent upward, the groove tends to fall downward at the joint between the outer peripheral edge of the metal base and the convex step. At the same time, the adhesive is sucked up by surface tension. Therefore, the adhesive is applied uniformly over the entire joint surface with almost no protrusion. Moreover, since the adhesive that has entered the recess is cured and then bonded to the case, the anchoring effect works to increase the bonding force between the metal base and the case.

〔Example〕

An embodiment of the present invention will be described below with reference to a comparative example shown in FIG. 1 and an embodiment shown in FIG. 1 and 2 are reference examples and embodiments corresponding to the package structures of FIGS. 3 and 4, respectively. The same members corresponding to those of FIGS. 3 and 4 are the same in each of the drawings. The reference numeral is attached.

That is, in FIGS. 1 and 2, a groove 11 is formed along the entire circumference at the central portion of the joint surface of the case frame 8 made as a resin molded product.

With such a configuration, an adhesive is applied to the bonding surface from a dispenser or the like.
When 10 is supplied and applied, the case frame 8 is superposed on the metal base 7 and a pressing force is applied, the adhesive 10 is spread over the entire joint surface, and the excess adhesive is spread over the concave groove 11 described above. It is sucked up by the capillary phenomenon and surface tension and accumulates here. Therefore, the adhesive 10 hardly squeezes out to the outer peripheral side of the package, and after the adhesive is hardened, the adhesive that has entered the concave groove firmly binds to the case frame 8 to enhance the bonding strength.

[Effect of device]

As described above, according to the package structure of the present invention, which has the convex step portion that fits to the outer peripheral edge of the metal base and the concave groove that serves as the adhesive reservoir on the joint surface of the case, the package assembly is performed. At that time, the surface tension and the capillary phenomenon prevent the adhesive from unnecessarily squeezing out from the package due to the pressing force in the bonding process, the capillary phenomenon and gravity, and firmly prevent between the case and the metal base. In addition to the fact that the product can be fixed and the reliability of the product is the same, the troublesome work of wiping off the protruding portion of the adhesive, which has been a problem in the conventional structure, is unnecessary, and the number of assembling steps can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part structure of a reference example, FIG. 2 is a cross-sectional view showing a main part structure of an embodiment, FIG. 3 is a cross-sectional view of a conventional semiconductor device as a whole, and FIG. It is a fragmentary sectional view of the conventional package structure different from a figure. 1: semiconductor element, 4: package, 5: gel sealing resin, 7: metal base, 8: case frame, 9: case lid, 10: adhesive, 11: groove.

Claims (1)

(57) [Scope of utility model registration request] 1. A metal base on which a semiconductor element is mounted is covered with a case made of an insulating material, and the two are joined by an adhesive to assemble, and a gel sealing resin is enclosed in the case. In the package of the semiconductor device, a concave groove serving as an adhesive reservoir facing the main surface of the metal base over the entire circumference of the bonding surface of the case to be bonded to the metal base having both flat main surfaces, and the concave A package structure for a semiconductor device, comprising: a convex step portion which is spaced apart from a groove and fits into an outer peripheral edge of the metal base.