Patent Application
20110127543
The present application claims priority to Japanese Patent Application No. 2009-273579, filed Dec. 1, 2009. The contents of this application are incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to sealing of a semiconductor element.
2. Discussion Of The Background
For example, Japanese Unexamined Patent Application Publication No. 6-112350 discloses a semiconductor device including a semiconductor element sealed with silicone gel on a substrate.
According to one aspect of the present invention, there is provided a semiconductor device including a substrate having a main surface, a semiconductor element disposed on the main surface and generating a heat of 200° C. or more, an enclosure surrounding the semiconductor element, and a liquid sealant containing a heat-resistant oil. The enclosure controls the flow of the sealant and seals the semiconductor element.
According to another aspect of the present invention, a semiconductor device is provided which includes a substrate, a semiconductor element made of SiC or GaN, and a sealant sealing the semiconductor element. The sealant contains a liquid oil resistant to the heat generated by the semiconductor element.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.
The semiconductor element 2 is made of SiC, GaN or the like and generates a heat of 200° C. or more.
The sealant 6 contains a heat-resistant liquid oil. Accordingly, the sealant can appropriately seal the semiconductor element 2 generating a heat of 200° C. or more. In addition, since a liquid oil is used as the sealant, thermal stress generated inside can be reduced.
A fluorocarbon oil GALDEN D40 produced by Solvay Solexis can be used as the sealant 6. A synthetic oil BARREL THERM 400 produced by Matsumura Oil may be used. Alternatively, a silicone oil BARREL SILICONE FLUID ST produced by Matsumura Oil may be used. While these liquid oils have been cited as examples of the sealant 6, it is to be understood that the sealant used in the invention is not limited to the cited examples, and that similar materials may be used within the scope and spirit of the invention.
Fluorocarbon oil has a heat resistance of about 250° C. If a fluorocarbon oil is used as the sealant 6, the semiconductor element can be operated at temperatures of almost 250° C. Synthetic oil has heat resistance of about 300° C. If a synthetic oil is used as the sealant 6, the semiconductor element can be operated at temperatures of almost 300° C. Silicone oil has heat resistance of about 400° C. If a silicone oil is used as the sealant 6, the semiconductor element can be operated at temperatures of almost 400° C.
Since the sealant 6 is bonded to none of the circuit substrate 1, the semiconductor element 2, the pads 3, the case 4 and the cover 5, thermal stress is not likely to occur due to the difference in thermal expansion coefficient. Consequently, the reliability of the semiconductor device can be increased.
In manufacture of the semiconductor device, first, a hybrid integrated circuit is prepared by mounting electronic components (not shown), such as a resistor and a capacitor, and a semiconductor element 2 on the pads 3 disposed on the circuit substrate 1 having a desired wiring pattern.
The circuit substrate 1 is fixed in the case 4 with, for example, an adhesive. Then, the case 4 is filled with the sealant 6 to seal the semiconductor element 2 and the electronic components. Further, the upper open end of the case 4 is closed with the cover 5. This operation is performed so that no air remains between the sealant 6 and the cover 5. The case 4 and the cover 5 are secured with an adhesive or an O ring therebetween, for example, by screwing.
The semiconductor device 200 of the second embodiment also includes a sealant 6B. The sealant 6B contains an insulating material 7. The insulating material 7 may be a powder of metal oxides such as silicon oxide and aluminium oxide, nitrides such as aluminium nitride and boron nitride, and hydroxides such as aluminium hydroxide and magnesium hydroxide. For example, a silicon oxide FB-74 produced by Denki Kagaku Kogyo may be used as the insulating material 7. The insulating material 7 is dispersed in the sealant 6B.
While these insulating materials have been cited as examples of the insulating material 7, it is to be understood that the insulating material used in the invention is not limited to the cited examples, and that similar materials can be used within the scope and spirit of the invention.
In the second embodiment, the same effect as in the first embodiment is produced and, in addition, the insulating material can form a thermal radiation path and impart incombustibility. Particularly in a semiconductor device generating a high temperature heat, the structure of the second embodiment can remarkably prevent the temperature increase of the semiconductor element.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-273579 | Dec 2009 | JP | national |
