| 摘要 |
PURPOSE:To improve the yield rate of manufacturing, by performing the formation of the channel stopper of an N-channel type MIS element and the introduction of P-type impurities for determining the threshold voltage value of the N-channel type MIS element by one ion implantation. CONSTITUTION:A reverse-conductivity type island-region N-well 3 is formed on a P-type semiconductor substrate 1. Thereafter, a silicon oxide film 5 and a silicon nitride film 6 are formed on the surface. Then patterning in carried out so that the silicon nitride film 6 is made to remain only at future P-type and N-type active regions by a photoresist step. Then a part between the region, which is to become a P-type active region, and the region is covered with photoresist 7, which is to become a protective film. For the region, which is to become an N-type active region, the threshold voltage value is determined. Boron ions are deeply implanted around the N-type active region so as to form a channel stopper, and a P-type diffused layer 11 is formed. Since the P-type diffused layer 11 can be formed by one ion implanting step in this way, the photoresist step can be made fewer. |
