JP2000228490A - Power semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the amount of warpage in a module, and to improve the dissipation of heat by providing at least one mounting hole for fixing the module on mounting at a part other than the periphery part of the module, and by directly fixing a base material with a bolt. SOLUTION: A semiconductor element 4 is jointed to an insulating board 3 by solder 15, bonding connection is made by an A1 wire 6 on the electrode of the semiconductor element 4 and the insulating board 3, and the insulating board 3 is connected to a metal base 101 by solder 2. Then, a mounting hole 102 for fixing a module is formed at a position other than the periphery part of the metal base 101, a case 11 made of organic resin is jointed to the metal base 101 where the insulating board 3 is jointed by adhesive 13, and at the same time a cylindrical case 103 made of the organic resin is jointed to the position of the mounting hole 102 other than the periphery part of the metal base 101, thus reducing the amount of warpage without changing the inside layout or the like of the module, and improving the dissipation of heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a power semiconductor module.

[0002]

2. Description of the Related Art Conventionally, IGBT, diode, GT
2. Description of the Related Art Power semiconductor modules in which power semiconductor elements such as O and transistors are sealed in an insulating container are known. These elements are applied to various inverter devices and the like according to their withstand voltage and current capacity. Among them, the IGBT is capable of high-frequency operation with a large current, and has advantages such as easy control because of a voltage control element. In many cases, the module has an internal insulation structure in which the base portion and the current-carrying portion are electrically insulated from the viewpoint of simplicity in using the module.

The structure of an IGBT module will be described with reference to FIG. Generally semiconductor element 4
Is bonded to the insulating substrate 3 by the solder 15, and the semiconductor element 4 and the electrodes of the insulating substrate 3 are connected by bonding with the Al wires 6 or the like to lead the electrodes. As the insulating substrate 3, one obtained by connecting a copper pattern to alumina or AlN ceramic is used. The insulating substrate 3 supports the bottom surface of the module, and is joined to the flat metal base 1 serving as a heat sink by solder 2. Around the metal base, there are provided mounting holes 16 for fixing the module when mounting the module on an inverter or the like. The connection between the external terminals of the module and the insulating substrate 3 is made by copper leads 7 integrated with the external terminals.
And 8 are joined to the electrode portion on the insulating substrate 3 by the solder 5. This external terminal is generally called a terminal block. Further, the organic resin case 11 is connected to the metal base 1 by an organic resin adhesive 13. In this, the semiconductor element 4 is cut off from the outside atmosphere, and a gel 9 is injected and cured for securing insulation inside the module and protecting wire bonding wiring. Then, an epoxy resin 10 is filled on the gel 9 and hardened to ensure airtightness inside the module. The above is the general manufacturing process and structure of the IGBT module. Japanese Patent Application Laid-Open No. 6-243654 can be mentioned as a module related to this type of module structure.

[0004] The amount of warpage of the back of the module is determined by joining the metal base 1 and the organic resin case 11 forming the side surface of the module with another organic resin adhesive 13 to form a module. It is determined by a difference in thermal expansion coefficient (hereinafter abbreviated as α) of the organic resin case 11. In general, organic resin case 1
Since α of 1 is large, after bonding the metal base 1 and the organic resin case 11, the organic resin case 11 expands and expands when the temperature is high due to the heat fluctuation of the module, and the rear surface is concave when the temperature is low. The case 11 shrinks and the rear surface is deformed to be convex. The amount of warpage on the back surface of the module tends to increase as the size of the module increases. Conventionally, in order to reduce the amount of warpage, a method is used in which the metal base 1 is previously warped in the opposite direction after the module is completed to reduce the amount of warpage after the module is completed. A method of increasing the tightening torque when mechanically fixing the module to the fins 12 or the like with the bolts 14 at the time of mounting the module to reduce the amount of warpage at the time of mounting. There has been a method of reducing the amount of warpage by increasing the thickness of the metal base 1 sufficiently to provide rigidity. Also, a hole is made in the center of the module to reduce the stress applied to the module.
No. 7-169906.

[0005]

The above prior art has the following problems.

In the method in which the metal base 1 is warped in advance to reduce the warpage after completion of the module, it is difficult to control the warpage in the module unless the warpage of the metal base 1 is constant. In addition, the method of increasing the tightening torque when mechanically fixing the module to the radiation fins 12 or the like with the bolts 14 requires that the mechanical strength of the mounting holes 16 around the metal base 1 be sufficiently ensured. As a result, the module area must be increased and the metal base 1 must be thickened. In addition, according to this method, if the warpage on the back surface of the module is concave, even if the bolt tightening force at the peripheral portion is increased, there is almost no effect of improving the adhesion between the metal base 1 and the radiation fins 12 at the center of the module. . In the method of making the metal base 1 sufficiently thick and having rigidity, the amount of warpage of the metal base 1 can be suppressed, but the thermal resistance of the module increases as the metal base 1 becomes thicker. In addition, the weight of the module increases. For this reason, the maximum usable loss and the mounting method are limited.

Further, Japanese Patent Application Laid-Open Nos. 9-27590 and 7-16990
In the method of No. 6, when fixing the module with the hole in the center, it is necessary to tighten the bolts through the case resin, and if the strength of the resin is not enough, the tightening torque at the time of installation can not be increased. As a result, the amount of warpage of the base material cannot be suppressed.

[0008]

In view of the above-mentioned problems, the power semiconductor module according to the present invention employs the following means.

At least one mounting hole for fixing the module at the time of mounting is provided at a portion other than the peripheral portion of the module, and the base material is directly fixed by bolts.

[0010] By directly fixing the base member with bolts having one or more mounting holes other than the peripheral portion of the module, the amount of warpage at the time of mounting the module can be reduced and the heat dissipation can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional structural view of a module to which the present invention is applied, and FIG. 2 is a plan view thereof. The semiconductor element 4 is joined to the insulating substrate 3 by the solder 15, and in order to lead the electrodes,
The semiconductor element 4 and the electrode of the insulating substrate 3 are bonded and connected by an Al wire 6. The insulating substrate 3 is connected to the metal base 1 with the solder 2. In this embodiment, the metal base 10
Mounting holes 1 for fixing the module at positions other than the periphery of 1.
02 is formed. Next, an organic resin case 11 is bonded to the metal base 101 to which the insulating substrate 3 is bonded with an adhesive 13, and at the same time, the mounting holes 1 other than the peripheral portion of the metal base 101
The cylindrical organic resin case 103 is joined at the 02 position.
At this time, in order to prevent the metal base 101 and the organic resin case 103 from peeling off, it is desirable to secure the adhesive strength by mechanically fixing both materials with bolts or the like. Metal base 101
Examples of the material include a Cu plate, a Mo plate, and a composite material AlSiC. However, the Cu plate and the Mo plate need to be drilled by machining, and the Mo plate is particularly difficult to machine due to its high hardness. Is done. For this reason, AlSiC or CU
A material formed by casting, such as SiC, is desirable. With these materials, since the hole is formed integrally with the metal base 101 by forming a metal mold, no mechanical processing is required, and it is easy to manufacture. Next, the terminal block 104 integrated with the external terminals of the module is connected to the insulating substrate 3.
It is joined to the upper electrode portion with solder 5. A hole is formed in the terminal block 104 in advance on the same vertical plane as the mounting hole 102 of the metal base 101. Subsequently, the gel 9 is injected into the module and hardened. The structure is such that the epoxy resin 10 is filled on the gel 9 in order to secure airtightness inside the module. In the semiconductor module described above, since the metal base 101 is directly fixed to the heat dissipating fins 12 by mounting holes 102 other than the module peripheral portion in addition to the module fixing mounting holes 16 in the module peripheral portion during mounting, The amount of warpage can be reduced, and the cooling efficiency can be improved by reducing the thermal resistance.
Further, since the amount of deformation of the module due to the temperature change is suppressed, the stress applied to the organic resin case 11 and the insulating substrate 3 is reduced, and the reliability of the semiconductor module can be improved.

FIGS. 3 and 4 show a second embodiment. 3 and 4, the same reference numerals as those in FIGS. 1 and 2 indicate the same elements. In this embodiment, mounting holes 106 for fixing the module at the time of module mounting are provided on the back surface of the metal base 105.
Is formed. By fixing the module to the fins 12 from the back surface by this method, the amount of warpage during mounting can be reduced. In the present embodiment, although the shape of the metal base 105 changes, the amount of warpage can be reduced without changing the layout inside the module and the manufacturing process, and the heat dissipation can be greatly improved.

In the above embodiment, an IGBT module has been described as an example. However, the present invention is not limited to this, and it is a matter of course that another power transistor, a GTO thyristor, or the like may be used.

[0015]

According to the present invention, it is possible to provide a highly reliable power semiconductor module having a reduced amount of module warpage and excellent heat dissipation.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view of the present invention shown in FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a plan view of the present invention shown in FIG. 3;

FIG. 5 is a sectional view showing a conventional structure.

FIG. 6 is a plan view of the conventional structure shown in FIG.

[Explanation of symbols]

1, 101, 105: metal base, 2, 5, 15: solder, 3: insulating substrate, 4: semiconductor element, 6: Al wire, 7, 8: copper lead, 9: gel, 10: epoxy resin, 11, 103: organic resin case, 12: fin,
13: adhesive, 14: bolt, 17, 104: terminal block, 16, 102, 106: module mounting hole.

Continued on the front page (72) Inventor Shigeyasu Takatsuchi 3- 10-2 Bentencho, Hitachi City, Ibaraki Prefecture Inside Hitachi Haramachi Electronics Co., Ltd. (72) Inventor Takashi Saito 3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture No.Hitachi Ltd.Hitachi Plant

Claims (3)

[Claims] 1. A base for supporting a module bottom, which is made of a material such as a metal or a composite material and also serves as a heat radiator, and an insulating substrate having a plurality of semiconductor elements bonded on the base. In an internal insulation type power semiconductor module covered with a resin case for shielding from the outside atmosphere, there is one or more mounting holes for fixing the module other than around the module, and the base is directly fixed with bolts Power semiconductor module characterized by the following. 2. The power semiconductor module according to claim 1, wherein one or more mounting holes for fixing the module are provided on a back surface other than a peripheral portion of the base. 3. The power semiconductor module according to claim 1, wherein said base is fixed to a radiation fin by said bolt.