JP2016012709A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which reduces warpage of a resin sealing body and a heat dissipation substrate, and improves adhesion and radiation performance of a whole package.SOLUTION: A semiconductor device of the present embodiment comprises: a semiconductor chip; a die pad for mounting the semiconductor chip; a heat dissipation substrate bonded to the other principal surface of the die pad; and a resin sealing body for resin sealing with an undersurface of the heat dissipation substrate being exposed, in which screw holes for fastening the resin sealing body by screws are provided and washers arranged between screw heads and the resin sealing body overlap ends of the heat dissipation substrate in a longer direction in a projection plane to sandwich the heat dissipation substrate.

Description

The present invention relates to a semiconductor device having a configuration in which a semiconductor chip is sealed in a resin sealing body, and a heat dissipation substrate that radiates heat from the semiconductor chip is exposed on a lower surface of the resin sealing body.

In recent years, there has been a demand for resin-encapsulated power semiconductor devices with excellent handling, high heat dissipation, and high reliability. The semiconductor chip is placed on the upper surface of the die pad connected to the lead frame, and the lower surface of the die pad and the upper surface of the heat dissipation substrate are bonded via an insulating resin sheet so that the lower surface of the heat dissipation substrate is exposed. And an insulating resin sheet and a mold resin for sealing the heat dissipation substrate.

Further, in the semiconductor device, a screw mounting hole for fixing the semiconductor device to the heat radiating fin is provided. By tightening a screw in this hole, the heat radiation board of the semiconductor device is attached in close contact with an external heat radiation fin or a circuit board. Thus, the heat generated in the semiconductor chip can be radiated from the heat dissipation substrate to the outside of the semiconductor device. (See Patent Document 1)

JP-A-2005-109100

Generally, the heat dissipation substrate is slightly curved when sealed with resin. Further, even the heat generated by the operation of the semiconductor chip is bent due to a difference in thermal expansion between the heat dissipation substrate and the resin sealing body.

According to the prior art, when the length of the package, which is a resin-encapsulated body, is relatively longer than that of the short side, that is, the shape has a high aspect ratio, in the vicinity of the screw hole, it is pressed by a screw stopper. Although effective, there is a problem that the pressing effect at the center of the package is reduced.

Accordingly, the present invention has been made to solve the above-described problems, and provides a semiconductor device in which the warpage between the resin sealing body and the heat dissipation substrate is reduced and the adhesion and heat dissipation of the entire package are improved. With the goal.

In order to solve the above-described problems, the present invention is configured as follows.
A semiconductor device according to the present invention includes a semiconductor chip, a die pad on which the semiconductor chip is placed, a heat dissipation substrate that is bonded to the other main surface of the die pad, and a resin sealing body that is resin-sealed by exposing the lower surface of the heat dissipation substrate. And a screw hole for fixing the resin sealing body with screws, and a washer disposed between the screw head and the resin sealing body and the longitudinal end of the heat dissipation substrate are overlapped by the projection surface. It is pinched.
In addition, a recess for receiving a washer is provided around the screw hole.

Since this invention is comprised as mentioned above, the curvature of a resin sealing body and a thermal radiation board | substrate can be reduced, and the semiconductor device which improved the adhesiveness and heat dissipation of the whole package can be provided.

1A is a conceptual plan view of a semiconductor device according to a first embodiment of the present invention, and FIG. It is a section conceptual diagram of a screw stop part of a semiconductor device concerning Example 1 of the present invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the dimensional relationship ratios and the like are different from the actual ones. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.
The following embodiments are exemplifications for embodying the technical idea of the present invention, and the embodiments of the present invention are described below in terms of the material, shape, structure, arrangement, etc. of the components. It is not something specific. The embodiments of the present invention can be implemented with various modifications without departing from the scope of the invention.

A semiconductor device 100 according to Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1A is a conceptual plan view of a semiconductor device according to a first embodiment of the present invention, and FIG.

As shown in FIG. 1, the semiconductor device 100 includes a semiconductor chip 1, a die pad 2, a heat dissipation substrate 3, and a resin sealing body 4.

The semiconductor chip 1 is placed and fixed on one main surface of the die pad 2. For example, a power element that generates a large amount of heat. Here, only one piece is illustrated in a simplified manner and the bonding material is omitted.

The die pad 2 is a part of a general semiconductor lead frame. Here, only the die pad 2 is illustrated in a simplified manner, and wiring such as terminals is omitted.

The heat dissipation substrate 3 is made of a metal plate, is electrically insulated from the die pad 2, and is joined by an insulating material. In order to efficiently dissipate the heat generated in the semiconductor chip 1 to the outside of the resin sealing body 4, it is desirable to have excellent heat conductivity. For example, aluminum or copper metal is used. Further, the heat dissipation substrate 3 is exposed on the lower surface of the resin sealing body 4.

The resin sealing body 4 is resin-molded as a transfer mold using a resin molding die and a press device. For example, a thermosetting epoxy resin is used for the resin sealing body 4.

In addition, the resin sealing body 4 has a rectangular plane, and a screw hole 41 passes through opposite ends in the longitudinal direction. Here, the lower surface of the semiconductor device 100 can be fixed to a radiating fin or the like (not shown) with screws. The lower surface is a heat radiating surface, and is a surface where the heat radiating substrate 3 is exposed from the resin sealing body 4. For example, an M4 screw can be used as the screw.

The washer 5 is inserted between the screw head and the resin sealing body 4. For example, it is a polished round (large washer) according to the ISO standard (new JIS), and the dimension of nominal diameter X inner diameter x outer diameter x thickness is M4X4.3X9X0.8 (mm).

In the semiconductor device 100, the positional relationship between the end of the heat dissipation substrate 3 in the longitudinal direction and the washer 5 is overlapped on the projection plane. That is, it is in a state of being sandwiched between the washer 5 and a radiation fin (not shown). For example, the overlapping portion L1 is 0.6 mm. (See Figure 2)

Next, effects of the semiconductor device according to the first embodiment will be described.

The heat dissipation substrate is required to have flatness, but is slightly curved when sealed with resin. Further, the heat of the semiconductor chip raises the temperature of the resin sealing body, and the thermal expansion coefficient differs between the heat dissipation substrate and the resin sealing body, so that the semiconductor device is deformed. The thermal expansion coefficient has a larger relationship with the resin sealing body than the heat dissipation substrate, and the semiconductor device 100 is warped like a bowl. That is, the end of the package in the longitudinal direction is lifted with respect to the center, which is also called a smile warp.

The semiconductor device according to the first embodiment of the present invention can correct the warpage of the heat dissipation board by positioning the heat dissipation board directly below the washer and using the screw tightening force when screwing. Thereby, the flatness of the heat dissipation substrate and the resin sealing body is improved, the adhesion between the heat dissipation fin and the package after tightening the screws is also improved, and the heat dissipation concern can be solved. Accordingly, the warpage between the resin sealing body and the heat dissipation substrate can be reduced, and the semiconductor device with improved adhesion and heat dissipation of the entire package can be obtained.

As described above, the mode for carrying out the present invention has been described. From this disclosure, it should be apparent to those skilled in the art that various alternative embodiments and examples are possible.

As Example 2, the recessed part which put the counterbore in the resin of the part which the resin sealing body 4 and the washer 5 contact can be formed. The recesses of the resin sealing body 4 are installed at both ends of the package, similarly to the positions of the screw holes 41. As a result, the volume of the resin having a large warping effect can be reduced, and the warpage due to mismatch of the thermal expansion coefficients in the region can be reduced. Furthermore, the adhesiveness and heat dissipation of the entire package can be improved.

The semiconductor device 100 may be an IPM (intelligent power module) in which a power element, a control element, a protection element, and the like are housed in the same package. In IPM, since a large current flows in motor drive control, it is important to take measures against heat generation, and the present invention can improve heat dissipation.

The semiconductor chip is generally a Si semiconductor, but can operate at a higher temperature than conventional Si semiconductors, and has a high switching speed and low loss, such as a compound semiconductor such as a SiC semiconductor or the like. It can also be composed of a compound semiconductor such as a GaN semiconductor.

DESCRIPTION OF SYMBOLS 1, Semiconductor chip 2, Die pad 3, Thermal radiation board 4, Resin sealing body 41, Screw hole 5, Washer 100, Semiconductor device

Claims (2)

A semiconductor chip; a die pad on which the semiconductor chip is placed; a heat dissipating substrate bonded to the other main surface of the die pad; a resin sealing body that exposes a lower surface of the heat dissipating substrate and encapsulates the resin; and the resin A semiconductor device having a structure provided with a screw hole for fixing a sealing body with screws, a washer disposed between a screw head and the resin sealing body, and a longitudinal end of the heat dissipation substrate The semiconductor device is characterized in that the portion is sandwiched by overlapping projection surfaces.
  The semiconductor device according to claim 1, wherein a recess into which the washer is inserted is provided around the screw hole.

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