Determining fuse current versus time characteristic - by adjusting diffusion of low melting point material into element material, typically tin and silver

摘要

The diffusion process is particularly applicable to determining current-time characteristics for semiconductor fuses. The method relates to fuses in which the melting point is determined by the addition of a reactive material at one point on the basic fuse element material, for example by adding tin to a silver strip. The additive material has a lower melting point than the base, but, when molten, reacts with the base to affect its melting point. In the process the additive material, typically tin, is diffused into the element material, silver, by a heat treatment process. The temperature and time relationship of this process are adjusted to give the required fusing characteristic. With the process the fuse can be designed for a specific duty, for example for a semiconductor a definite knee point between short circuit and long time fusing can be introduced.