| 摘要 |
PROBLEM TO BE SOLVED: To obtain a coating method, which extends the useful life time of a power semiconductor chip by a method, wherein a coating material is composed of a high- purity polymeric inert material which can extend the useful life time of a connecting wire for the power semiconductor chip. SOLUTION: A high-purity polymeric inert material is used as a coating material. The inert material is composed of a material similar to a polyimde, which is used for the passivation of a semiconductor. The coating material is dried at a temperature of about 80 deg.C, then polymerized at a temperature of about 180 to 280 deg.C, and a mechanical stress can be made to act on a connecting wire at the inside of a rigid armor. When the coating material is polymerized, the annealing operation of an aluminum connecting wire connected to a chip is induced indirectly. At the coating stage of the connecting wire, aluminum crystal grains in a welding interface are made enlarged, the thermal fatigue resistance of the welding part of the chip to the aluminum connecting wire is intensified, and the useful life time of a power semiconductor chip can be extended.
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