Patent ID: 6066522
Filing Date: 2000-05-23
Classification: H01L

Abstract:
A method for producing a semiconductor device, comprising the steps of:performing ion implantation into a substrate of a first conductivity type, thereby forming a first well of a second conductivity type at a deep position in the substrate;performing ion implantation into the substrate, thereby forming a second well of the first conductivity type and a third well of the first conductivity type both in contact with a top portion of the first well;forming a fourth well of the second conductivity type at a position corresponding to an area between the second and third wells, the fourth well being formed so as to be in contact with a top portion of the first well; andperforming ion implantation, thereby partially counteracting a part of the first well which is just below the third well and instead forming therein a fifth well of the first conductivity type.