JPH04274350A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a stripping shake of a semiconductor element even force is applied between a base plate and an external and an external lead-out terminal by engagedly joining a metal base plate with a case, the case with resin for sealing and the sealing resin with an external terming. CONSTITUTION:A semiconductor element 2 and an external lead-out terminal 3 are mounted on a metal base plate 1 by soldering to assemble a case 4 on the metal base plate 1. In this assembling process, the case 4 is put on the metal, base plate 1 from above, and a rivet leg part 4a of the case 4 is inserted into a rivet hole 1a so as to adhere the case 4 to the metal base plate 1 and heat a tip of the rivet leg part 4a from the rear side of the metal base plate 1 in this state for being taperedly shaped. Thereby, the metal base 1 and the case 4 are jointed by riveting. Next, the inside of the case 4 is filled with sealing resin 5 for being hardened.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a molded semiconductor device, such as a power semiconductor module, in which the case of a package incorporating a semiconductor element is filled with a sealing resin.

0002

2. Description of the Related Art As the above-mentioned mold type semiconductor device, a structure shown in FIG. 3 is known. In the figure, 1 is a metal base plate (copper plate) that also serves as a heat sink and an electrode terminal;
2 is a semiconductor element soldered and mounted on the metal base plate 1; 3 is an external lead-out terminal that is stood up on the upper surface of the semiconductor element 2 and soldered; 4 is a semiconductor element surrounding the semiconductor element 2 and mounted on the metal base plate 1. The attached resin case 5 is a sealing resin (epoxy resin) filled inside the case 4, and the metal base plate 1 and the case 4 are bonded together with an adhesive 6.

0003

By the way, it has been empirically found that with the semiconductor device having the above structure, the following troubles often occur during actual handling operations. That is, if a somewhat excessive tensile force is applied between the metal base plate 1 and the external lead-out terminals 3 when the semiconductor device is installed at the place of use, the semiconductor element 2 will easily suffer from peeling cracks.

[0004] The inventors investigated the cause of such exfoliation cracks in semiconductor elements and found that the cause lies in the following points. That is, metal base plate 1
, Since the external lead-out terminal 3 is usually made of copper, its bonding force with the sealing resin 5 is low, and the bonding force between the metal base plate 1 and the resin case 4 bonded with the adhesive 6 is also tensile. relatively weak against Therefore, if a somewhat excessive tensile force is applied between the metal base plate 1 and the external lead-out terminal 3, the case 4 and the sealing resin 5 will be peeled off from the metal base 1, and the external lead-out terminal 3 will be stopped in the assembled position. As a result, the external lead-out terminal moves in the tensile direction, and tensile stress directly acts on the semiconductor element 2 soldered to the external lead-out terminal 3, causing peeling cracks in the semiconductor element. .

The present invention has been made in consideration of the above points, and by improving the assembly structure, it is possible to easily apply a somewhat excessive tensile force between the metal base plate and the external lead-out terminal. An object of the present invention is to provide a semiconductor device with a solid structure in which peeling cracks do not occur in semiconductor elements.

[0006]

[Means for Solving the Problems] In order to solve the above problems, in the semiconductor device of the present invention, there are The external lead-out terminals are connected to each other via locking and connecting means.

Here, as a means for locking and connecting the metal base plate and the case, a rivet hole is formed in the metal base plate, and a rivet is provided protruding from the lower end surface of the case opposite to the rivet hole. Legs are formed, and the rivet legs are inserted into the rivet holes and caulked from the back side. Further, as a means for locking and connecting the case and the sealing resin, a horizontal groove is formed on the inner wall surface of the case to lock and connect the case and the sealing resin. Furthermore, as a means for locking and connecting the sealing resin and the external lead-out terminal, a through hole is drilled in the portion of the external lead-out terminal that is buried in the layer of the sealing resin and lockingly connects the sealing resin and the lead-out terminal. It shall be.

[0008]

[Function] In the above structure, first, between the external lead-out terminal and the sealing resin, the sealing resin enters the through hole of the external lead-out terminal, and its anchoring effect firmly connects the two. . Further, between the sealing resin and the case, the resin bites into the groove in the inner wall of the case, and the anchoring effect similar to that described above prevents the two from shifting relative to each other in the vertical direction. Furthermore, since the rivet legs of the case are inserted into the rivet holes of the metal base and the rivets are tightened between the case and the metal base plate, a strong connection is ensured. As a result, in the entire semiconductor device, the external terminals and the metal base plate are integrally connected via the sealing resin and the case.
Moreover, a firm locking and coupling state is ensured. Therefore, even if tensile stress is applied between the metal base plate and the external lead-out terminal, the external lead-out terminal will not move in the tensile direction with respect to the metal base unless the locking joints of each part are broken, and the semiconductor element Peeling cracks can be reliably prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show the structure of an embodiment of the present invention, and the same members corresponding to those in FIG. 3 are given the same reference numerals. 1 and 2, among the components of the semiconductor device, we will first discuss the points that differ from the structure in FIG. 1a is perforated. On the other hand, the lower surface of the case 4 is provided with cylindrical protruding rivet legs 4a at four locations corresponding to the rivet holes 1a, and furthermore, the entire inner wall surface of the case 4 has a plurality of grooves 4 extending laterally.
b is formed. In addition, the rivet leg portion 4a and the groove portion 4
b is molded at the same time as the case 4, which is a resin molded product, is molded. Furthermore, a through hole 3 a is bored in the external lead terminal 3 in a region buried in the layer of the sealing resin 5 .

Next, the assembly procedure of the semiconductor device will be explained.
First, the semiconductor element 2 and the external lead-out terminals 3 are soldered and mounted on the metal base plate 1, and then the case 4 is mounted on the metal base plate 1.
Assemble. In this assembly process, the case 4 is placed on the metal base plate 1 from above, and the rivet holes 1a are
Insert the rivet leg 4a of the case 4 into the metal base plate 1 to bring the case 4 and the metal base plate 1 into close contact with each other.
The tip of the rivet leg 4a is heated from the back side of the rivet leg 4a to shape it into a wedge shape as shown in the figure. As a result, the metal base 1 and the case 4 are connected by riveting. Next, case 4
When the sealing resin 5 is filled into the inside and hardened, the semiconductor device is completed.

In this assembled state, the sealing resin 5 has entered the through hole 3a of the external lead terminal 3 and the groove 4b of the inner wall surface of the case 4, and the sealing resin 5 has also entered the metal base plate 1.
and the case 4 are fastened with rivets as described above. In other words, the connection between the metal base plate 1 and the external lead-out terminal 3 is made firm through the case 4 assembled as described above and the sealing resin 5, in addition to the soldered joint through the semiconductor element 2. It is locked and coupled to. As a result, even if a tensile force is applied between the metal base plate 1 and the external lead-out terminal 3 in the assembled state, the tensile stress will not be applied to the solder joint between the semiconductor element 2 and the case 4 and the seal. It is received at the locking joint between each component including the locking resin 5. Therefore, unless an excessive force is applied that would break the locking joint between the parts, the metal base plate 1 and the external lead-out terminal 3
2 do not move relative to each other, and the semiconductor element 2 can be reliably protected from peeling cracks.

0012

[Effects of the Invention] Since the semiconductor device of the present invention is constructed as described above, for example, when installing the semiconductor device at the place where it is used, there may be some force between the metal base plate and the external lead-out terminal. Even when a tensile force is applied, the external lead-out terminal does not shift and move, thereby reliably preventing peeling cracks in the semiconductor element and greatly improving product reliability.

[Brief explanation of the drawing]

[Fig. 1] A cross-sectional view of the configuration of an embodiment of the present invention

[Figure 2] Plan view of Figure 1

[Figure 3] A cross-sectional view of the configuration of a conventional semiconductor device

[Explanation of symbols]

1 Metal base plate 2 Semiconductor device 3 External lead-out terminal 3a　Through hole 4 Case 4a Rivet leg 4b Groove 5 Sealing resin

Claims (4)

[Claims] 1. A metal base plate, a semiconductor element mounted on the metal base plate, an external lead-out terminal vertically connected to the upper surface of the semiconductor element, and a case surrounding the semiconductor element and attached to the metal base plate; In a semiconductor device consisting of a sealing resin filled inside the case, there are A semiconductor device characterized in that it is coupled via locking coupling means. 2. In the semiconductor device according to claim 1, a rivet hole is formed in the metal base plate as a locking connection means between the metal base plate and the case, and a rivet hole is formed in the case opposite to the rivet hole. A semiconductor device characterized in that a rivet leg is formed protruding from a lower end surface, the rivet leg is inserted into the rivet hole, and the rivet leg is caulked from the back side. 3. In the semiconductor device according to claim 1, a horizontal groove is formed in the inner wall surface of the case to engage the sealing resin as a locking connection means between the case and the sealing resin. A semiconductor device characterized by being fixedly coupled. 4. The semiconductor device according to claim 1, as a locking connection means between the sealing resin and the external lead-out terminal.
1. A semiconductor device characterized in that a through hole is formed in a portion of an external lead-out terminal buried in a layer of a sealing resin so as to be locked and connected to the sealing resin.