JPH0730011A - Semiconductor device - Google Patents

Abstract

PURPOSE:To efficiently transfer the heat generated by a semiconductor element to the back side of a substrate by inserting a heat-conducting member into a through hole. CONSTITUTION:A heat conducting material is inserted into a copper-plated through hole 7 in a substrate 2, and the heat conducting material 8 is directly connected to fins 9 which are formed by cooling material. As a result, the through hole 7 is almost filled up by the heat conducting material 8, and the heat of a semiconductor element can be introduced to the fins 9 efficiently by the heat conducting material 8. Also, when heat conducting grease 10 is interposed between the back side of the semiconductor element 1 and the heat conducting material 8, the heat of the semiconductor element 1 is transferred to the heat conducting material 8 by the heat conducting grease 10, and heat can be transferred effectively even when the surface, where the back side of the semiconductor element 1 and the heat conducting material 8 are brought into contact with each other, is poorly processed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a semiconductor element directly mounted on a substrate.

[0002]

2. Description of the Related Art In a semiconductor device in which a semiconductor element is directly mounted on a substrate, depending on the semiconductor element, deterioration of electric characteristics due to heat generation of the element poses a problem. Therefore, it is necessary to cool the semiconductor element. As a method, as described in Japanese Patent Laid-Open No. 64-80032, the semiconductor element is TAB (Tape Automete
d Bonding System) is used for face-up connection, and the back surface of the semiconductor element is brought into contact with the substrate to release the heat of the semiconductor element to the substrate. Here, in the case of a substrate having poor heat conduction, for example, in the case of a glass / epoxy substrate, etc., reference is made to the literature (IEICE Technical Report, ICD92-133, 19).
As described in the December 1992 issue, pp. 53-58), the semiconductor elements are connected face-up by TAB, a large number of through holes are provided in the substrate on the back surface of the semiconductor elements, and the heat generated by the semiconductor elements is generated by the copper in the through holes. A method has been used in which heat is transferred to a copper-plated portion on the back surface of the substrate via plating, and the back surface of the substrate is forcibly air-cooled to cool the semiconductor device.
In these methods, the elasticity of the TAB tape can bring the semiconductor element into contact with the substrate, and the semiconductor element and the substrate can be kept in contact without soldering or the like. Therefore, it is not necessary to match the thermal expansion coefficients of the semiconductor element and the substrate, and the semiconductor device can be configured relatively easily.

[0003]

In the case of such a structure, there are the following problems. That is, since it is a method of transferring heat to the substrate, the higher the thermal conductivity is, the better the material of the substrate is, but there is a limit in terms of workability, mountability, price, etc. of the substrate. In addition, inexpensive glass with low thermal conductivity
In the method of releasing heat from the through holes using an epoxy board, etc., heat transfer from the front side to the back side of the board is mainly limited to the copper plating part in the through holes, and it is not expected to greatly improve heat dissipation characteristics. There was a problem.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor device capable of efficiently transmitting the heat generated by a semiconductor element to the back side of a substrate.

[0005]

That is, in a semiconductor device in which the heat generated by the semiconductor element is radiated from the through hole provided in the substrate to the back side of the substrate, the heat transfer in the substrate is improved by inserting the heat conducting member into the through hole space. . By directly contacting this heat conducting member with the back surface of the semiconductor element, heat is transferred quickly. Further, by placing a heat conducting member in a viscous state between the heat conducting member inserted in the through hole space and the back surface of the semiconductor element, distortion due to the difference in thermal expansion between the substrate and the heat conducting member inserted in the through hole space is caused. There is a feature that can be removed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a semiconductor device 1 on a substrate 2 which is TAB.
In the example mounted by the method, the TAB lead 3 is connected to the board-side terminal 4 and the semiconductor element-side terminal 5. The semiconductor element 1 is sealed with a sealing resin 6 to protect the element. A heat conductive member 8 is inserted in the space of the copper-plated through hole 7 in the substrate 2. Further, the heat conducting member 8 is directly connected to the fin 9 which is a cooling member in this embodiment. The fins 8 are engaged with the back surface of the substrate 2 by an adhesive material (not shown). According to this embodiment, the inside of the through hole 7 is almost filled with the heat conducting member 8,
The heat generation of the semiconductor element 1 can be efficiently guided to the fins 9 by the heat conducting member 8. Therefore, the gold plating inside the through hole 7 can be omitted except when the front and back of the substrate 2 need to be electrically connected. Furthermore, FIG.
2 shows an example in which the thickness of the heat conducting member 8 is made slightly thicker than the thickness of the substrate 2 and the heat conducting member 8 is pressed against the back surface of the semiconductor element 1 by the elastic force of the TAB lead 3. By adopting this method, the contact state between the semiconductor element 1 and the heat conducting member 8 can be kept good, and therefore the heat transfer characteristics can be further improved. Further, FIG. 3 shows another embodiment of the present invention.
The back surface of the semiconductor element 1 and the heat conducting member 8 have a structure in which a heat conducting grease 10 is interposed. The fin 9 is connected to the substrate 2 by an adhesive material (not shown). In the present embodiment, the heat generated by the semiconductor element 1 is transferred to the heat conducting member 8 by the heat conductive grease 10. Therefore, even if the processing accuracy of the surface where the back surface of the semiconductor element 1 and the heat conducting member 8 abut is poor, the heat transfer can be prevented. It can be done efficiently. Further, FIG. 4 shows an embodiment by the wire bonding method, in which the semiconductor element 1 and the substrate 2 are electrically connected by using the gold wire 11 here, and the mechanical connection is made by using the elastic adhesive material 12. The elastic adhesive material 12 used here is a silicone resin. Then, the heat generated by the semiconductor element 1 is transmitted to the heat conductive member 8 via the heat conductive grease 10 and radiated by the fins 9. The fin 9 is fixed to the substrate 2 with an adhesive material 13.
Also in this embodiment, the heat generated by the semiconductor element 1 is generated by the heat conductive grease 1.
0 is efficiently transmitted to the heat conducting member 8. Also,
Since the difference in thermal expansion between the semiconductor element 1 and the substrate 2 is mitigated by the elastic adhesive material 12, it is possible to prevent the semiconductor element 1 from being broken. Further, since the difference in thermal expansion between the heat conductive member 8 and the substrate 2 is absorbed by the heat conductive grease 10, the semiconductor element 1 is not destroyed. The adhesive material 13 may be the elastic adhesive material 12, and in this case, the difference in thermal expansion between the substrate 2 and the fin 9 can be absorbed. FIG. 5 shows an embodiment in which a plurality of semiconductors 1 are mounted on a substrate 2 by a wire bonding method. For the purpose of hermetically sealing the semiconductor element 1 and reducing thermal stress, a silicone gel 14 is used.
It was sealed by. Then, in order to protect the semiconductor element 1 from an external force, the whole of the plurality of semiconductor elements 1 is capped.
5 is covered with the fixing adhesive 16 and the other structure is the same as that of FIG. 4 of the embodiment. According to the present embodiment, a plurality of semiconductor elements 1 can be mounted at high density, a heat dissipation characteristic is good, and an inexpensive semiconductor device having high strength can be provided.

[0007]

According to the present invention, in a semiconductor device in which a semiconductor element is directly mounted on a substrate, good heat dissipation characteristics can be obtained with a relatively simple structure. Further, since the heat conducting member inserted in the through hole can obtain sufficient heat transfer, copper plating in the through hole can be omitted unless it is necessary for electrical characteristics. Furthermore, since a glass / epoxy substrate or the like can be used as the substrate material, the device can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a TAB type semiconductor device using the present invention.

FIG. 2 is a sectional view showing a second embodiment of a TAB semiconductor device using the present invention.

FIG. 3 is a sectional view showing a third embodiment of a TAB semiconductor device using the present invention.

FIG. 4 is a sectional view showing an embodiment of a wire bonding type semiconductor device using the present invention.

FIG. 5 is a sectional view showing another embodiment of a wire bonding type semiconductor device using the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor element, 2 ... Substrate, 3 ... TAB lead, 7 ... Through hole, 8 ... Thermal conductive member, 10 ... Thermal conductive grease.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Touchi 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Ltd. Information & Communication Division

Claims (1)

[Claims] 1. A semiconductor device in which a back surface of a semiconductor element is bonded to one surface of a substrate having a through hole and a cooling member is bonded to a surface on the opposite side of the substrate, and a heat conducting member is provided in a space of the through hole. A semiconductor device characterized by the above.