A semiconductor device includes a semiconductor chip, a first heat sink, a second heat sink, and a mold resin. The first heat sink is electrically and thermally connected to a surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and releasing the heat generated by the semiconductor chip. The second heat sink is electrically and thermally connected to another surface of the semiconductor chip for functioning as another electrode for the semiconductor chip and releasing the heat. The semiconductor chip and the first and second heat sinks are covered with the mold resin such that the heat sinks are exposed on a substantially flat surface of the mold resin.
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1. A semiconductor device comprising:
a semiconductor chip, which generates heat; a first heat sink, which is electrically and thermally connected to a first surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and releasing the heat; a second heat sink, which is electrically and thermally connected to a second surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and releasing the heat; and a mold resin, wherein the semiconductor chip and the heat sinks are covered with the mold resin such that the heat sinks are exposed on one surface of the mold resin, wherein the one surface is a substantially flat surface.
8. A semiconductor device comprising:
a semiconductor chip, which generates heat; a first heat sink, which is electrically and thermally connected to a first surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and releasing the heat; a second heat sink, which is electrically and thermally connected to a second surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and releasing the heat; an insulating layer, which is located between the heat sinks; and a mold resin, wherein the semiconductor chip, the heat sinks, and the insulating layer are covered with the mold resin such that one of the heat sinks is exposed on a substantially flat surface of the mold resin and wherein the heat sinks are thermally connected by the insulating layer.
15. A semiconductor package, comprising:
a semiconductor chip; a first heat sink electrically and thermally connected to a first surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and for releasing heat generated by the semiconductor chip; a second heat sink electrically and thermally connected to a second surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and for releasing the heat generated by the semiconductor chip; and a mold resin covering the semiconductor chip and the heat sinks such that the first heat sink is exposed on one substantially flat surface defined by the mold resin, wherein the second heat sink includes a center portion attached to the second surface of the semiconductor chip and at least one end portion attached to a surface of the first heat sink.
2. The semiconductor device in
3. The semiconductor device in
4. The semiconductor device in
5. The semiconductor device in
6. The semiconductor device in
another first heat sink, wherein the another first heat sink is electrically and thermally connected to a first surface of the another semiconductor chip for functioning as an electrode for the another semiconductor chip and releasing the heat generated by the another semiconductor chip, wherein the second heat sink is electrically and thermally connected to a second surface of the another semiconductor chip for functioning as an electrode for the another semiconductor chip and releasing the heat generated by the another semiconductor chip, and wherein the another semiconductor chip and the another first heat sink are covered with the mold resin such that the another first heat sink is exposed on the substantially flat surface.
7. The semiconductor device in
9. The semiconductor device in
10. The semiconductor device in
11. The semiconductor device in
12. The semiconductor device in
13. The semiconductor device in
14. The semiconductor device in
16. The semiconductor device as in
17. The semiconductor device as in
18. The semiconductor device as in
19. The semiconductor device as in
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This application is based on and incorporates herein by reference Japanese Patent Applications No. 2001-397543 filed on Dec. 27, 2001 and No. 2002-312615 filed on Oct. 28, 2002.
The present invention relates to a semiconductor device in which a semiconductor chip generating heat is located between a pair of heat sinks and to a method for manufacturing the device.
A semiconductor chip for controlling large electric power and current generates so much heat in use that a proposed semiconductor device including the chip includes a pair of heat sinks, which are made of a metal such as copper and aluminum, to efficiently release the heat generated by the chip. As shown in
The upper and lower heat sinks 4, 3 also function as electrodes for the semiconductor chip. A mold resin 6 is located between the heat sinks 3, 4 to seal the chip 2, the coupler 5, and the solders. As illustrated in
As shown in
In the semiconductor device 1, the upper and lower heat sinks 4, 3 are exposed, so the insulating sheets 8 are needed to insulate the exposed surfaces and the metal fixer 9 is needed to transmit the heat generated by the chip 2 from the upper heat sink 4 to the cooling member 7. Therefore, the structure of the assembled article shown in
In addition, the thickness of the semiconductor device 1 deviates to some degree. Therefore, when the semiconductor device 1 is fixed to the cooling member 7 with the metal fixer 9, it is difficult to control the force with which the metal fixer 9 presses the device 1 against the cooling member 7. When the thickness of the semiconductor device 1 deviates too much from a predetermined value, the semiconductor device 1 breaks or is not firmly fixed to the cooling member 7. If only the insulating sheets 8 absorbed the force enough, the above problem could be solved. However, no material that is elastically shrinkable enough to be used for the insulating sheets 8 has been available yet.
Moreover, in the semiconductor device 1, the heat generated by the semiconductor chip 2 is partially transmitted from the upper heat sink 4 to the cooling member 7 through one of the insulating sheets 8 and the metal fixer 9. Therefore, the heat transmission path through the upper heat sink 4 is much longer than that through the lower heat sink 3, so the upper heat sink 4 releases the heat less efficiently than the lower heat sink 3.
The present invention has been made in view of the above aspects. A first object of the present invention is to reduce the manufacturing cost of a semiconductor power device by simplifying the means for insulating a heat sink and the means for releasing heat from the heat sink. A second object of the present invention is to improve the heat releasing capability of the heat sink.
In the present invention, a semiconductor device includes a semiconductor chip, a first heat sink, a second heat sink, and a mold resin. The first heat sink is electrically and thermally connected to a surface of the semiconductor chip for functioning as an electrode for the semiconductor chip and releasing the heat generated by the semiconductor chip. The second heat sink is electrically and thermally connected to another surface of the semiconductor chip for functioning as another electrode for the semiconductor chip and releasing the heat. The semiconductor chip and the heat sinks are covered with the mold resin such that the heat sinks are exposed on a substantially flat surface of the mold resin.
With the above structure, the means for insulating the heat sinks and releasing heat from the semiconductor chip become simple, so the device is preferably cost-effective in the manufacturing and has preferable heat releasing capability.
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
The present invention will be described in detail with reference to various embodiments.
First Embodiment
As shown in
The semiconductor chip 12 is, for example, a power semiconductor such as an insulated gate bipolar transistor (IGBT) and a thyristor in the shape of, for example, a thin rectangular plate. The upper heat sink 14, the lower heat sink 13, and the coupler 15 are made of, for example, copper. Instead of copper, a metal having relatively high heat conductivity and electric conductivity such as aluminum may be used.
As illustrated in
The upper and lower heat sinks 14, 13 are electrically connected to the semiconductor chip 12 through the coupler 15 and the solder 16 to respectively function as, for example, a collector electrode and an emitter electrode. Although not illustrated, a control electrode of the semiconductor chip 12 such as a gate pad is electrically connected to a lead frame, which protrudes from the mold resin 17, with a bonding wire.
Each heat sink 14, 13 has a thickness of about 1 mm. The upper heat sink 14, which includes an extension 14a, is formed by bending a metal plate. The upper and lower heat sinks 14, 13, the coupler 15, and the solders 16 are embedded in the mold resin 17, which is made of, for example, an epoxy resin, such that the extension 14a and the lower heat sink 13 are exposed on the lower surface 19 of the mold resin 17 and the exposed surfaces of the extension 14a and the lower heat sink 13 are substantially on a common plane, as illustrated in FIG. 3. The mold resin 17 is formed by insert molding, in which the upper and lower heat sinks 14, 13, the coupler 15, and the solders 16 are molded with the epoxy resin using a pair of molds, which are not illustrated.
As illustrated in
When the semiconductor device 11 is attached to a cooling unit 20 as shown in
The insulating sheet 22 is made of an insulating material that is thermally conductive and elastically shrinkable to a predetermined degree. The cooling member 21 is made of a metal such as copper and aluminum, which can efficiently release heat. Although not illustrated, the cooling member 21 includes a cooling water passage.
Then, a U-shaped plastic fixer 23 is placed on a predetermined position, and the semiconductor device 1 is fixed to the cooling member 21 by tightening male screws 24 to complete the attachment of the semiconductor device 11 to the cooling unit 20.
In the assembled article of
Moreover, the heat generated by the semiconductor chip 12 is preferably transmitted and released from its two surfaces to the cooling member 21 through the coupler 15, the upper and lower heat sinks 14, 13, and the insulating sheet 22. Therefore, the net heat transmission path in the assembled article of
In the assembled article of
Second Embodiment
As shown in
Third Embodiment
As shown in
As illustrated in
The left and right heat sinks 30, 31, which are approximately cubic, are made of a metal such as copper and aluminum, which is a thermally and electrically excellent conductor. As illustrated in
In the device 11 of
Fourth Embodiment
As shown in
As illustrated in
Fifth Embodiment
As shown in
As illustrated in
The device 11 of
The device 11 of
Sixth Embodiment
As shown in
The metal feet 43, 44 and the lower heat sink 13 are exposed on the lower surface 19 of a mold resin 17 and the exposed surfaces of the metal feet 43, 44 and the lower heat sink 13 are substantially on a common plane. The device 11 of
In the device 11 of
Seventh Embodiment
As shown in
As illustrated in
Each insulating layer 48 includes a ceramic sheet made of, for example, aluminum nitride (AlN) or aluminum oxide (Al2O3). In the manufacturing process of the device 11, a semiconductor chip 12, a coupler, upper and lower heat sinks 47, 46 are soldered with solders 16 to form a clearance of, for example, about 100 μm between each extension 47a and the lower heat sink 46. Then, a ceramic sheet is interposed between each extension 47a and the lower heat sink 46 with a material such as silicone grease, silicone gel, and silicone adhesive such that the material is located between each extension 47a and the ceramic sheet and between the ceramic sheet and the lower heat sink 46.
Therefore, the insulating layers 48 have preferable insulation capability and heat conductivity. The material, the structure, and the dimension of each insulating layers 48 need to be determined on the basis of the characteristics such as the breakdown voltage and thermal resistance that are required to the insulating layers 48.
In semiconductor device 11 of
In the semiconductor device of
Alternatively, ceramic films are formed beforehand on the lower surfaces of the extensions 47a and the upper surface of the lower heat sink 46. Then, each extension 47a and the lower heat sink 46 are thermally connected in the manufacturing process such that a material such as silicone grease, silicone gel, and silicone adhesive is located between the ceramic film on each extension 47a and corresponding ceramic film on the lower heat sink 46.
Alternatively, each insulating layer 48 may be formed using a resin such as epoxy resin and polyimide resin. Specifically, the resin is placed and cured between each extension 47a and the lower heat sink 46 in the manufacturing process. An inorganic filler may be added to the resin.
Eighth Embodiment
As shown in
Ninth Embodiment
As shown in
In the semiconductor device 11 of
Nevertheless, the upper heat sink 50 of
Tenth Embodiment
In the assembled article of
Instead of being coated on the ceramic board, the material may be coated on the upper surface of the cooling member 21, at which the cooling member 21 is thermally connected to the ceramic board, and the exposed surface of the lower heat sink 46.
Eleventh Embodiment
In the assembled article of
Instead, the insulating layer 52 may be formed on the upper surface of the lower heat sink 46 by thermally spraying a ceramic material. Alternatively, the insulating layer 52 may be formed using a resin such as epoxy resin and polyimide resin. An inorganic filler may be added to the resin.
When the semiconductor device 11 is fixed to the cooling member 21 in the manufacturing process, it is preferred that a material such as silicone grease, silicone gel, and silicone adhesive be placed between the insulating layer 52 and the cooling member 21. The assembled article of
Twelfth Embodiment
As shown in
As illustrated in
Nakase, Yoshimi, Hirano, Naohiko, Teshima, Takanori, Miura, Shoji
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