| 摘要 |
PURPOSE:To facilitate changing a circuit connection without removing a protective film formed as an upper layer and protect a fuse element from the influence of contamination and moisture by a method wherein a plurality of wiring layers which connect 1st and 2nd diffused regions to external circuits and a light is applied to a part of the 1st diffused region to make the two diffused regions electrically continuous. CONSTITUTION:On a P-type substrate, an N-type well region 1 whose conductivity type is opposite to that of the substrate is formed. A P-type diffused region 2 whose conductivity type is the same as that of the substrate and an N-type diffused region 3 whose conductivity is the same as that of the well region 1 are formed in the N-type well region 1. The respective diffused regions 2 and 3 are connected to wiring layers 5 made of metal such as aluminum through contact holes 4 and the diffused regions 2 and 3 are connected to external circuits by the wiring layers 5. P-N junctions are formed at the side surfaces and the bottom surface of the P-type diffused region 2. Normally, the respective diffused regions 2 and 3 are connected to the external circuit so as to provide reverse bias conditions at their junction boundaries and, if necessary, a laser beam is applied to the circumference of the diffused region 2, for instance the position X, to break the P-N junction and the diffused region 2 and the diffused region 3 are electrically connected to each other.
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