Patent ID: 7632732
Filing Date: 2009-12-15
Classification: H01L

Abstract:
1. A method comprising: forming a first well in a silicon substrate; and then forming a first mask pattern over the silicon substrate; and then forming a second well in the silicon substrate using the first mask pattern as a mask; and then removing the first mask pattern; and then forming a second mask pattern over the silicon substrate; and then forming a first drift region in the silicon substrate using the second mask pattern as a mask; and then removing the second mask pattern; and then forming a third mask pattern over the silicon substrate; and then forming a second drift region in the silicon substrate using the third mask pattern as a mask; and then removing the third mask pattern; and then forming a field oxide film over the silicon substrate; and then introducing first conductive impurity ions into an upper surface of the silicon substrate by performing a channel ion implantation process.