Patent ID: 7560359
Filing Date: 2009-07-14
Classification: H01L

Abstract:
1. A method of forming a recess, the method comprising: etching a semiconductor substrate to form a first sub-recess having a first central axis, wherein the first sub-recess has a first side face and a second side face facing the first side face; forming first and second mask patterns on the first and second side faces, respectively, wherein the first and second mask patterns have first and second lengths, respectively, and wherein the second length is substantially larger than the first length; and forming a second sub-recess under the first sub-recess, wherein the second sub-recess is in communication with the first sub-recess, wherein the second sub-recess has a second central axis that is substantially parallel with the first central axis, and wherein the second central axis is spaced apart from the first central axis.