Patent ID: 7008834
Filing Date: 2006-03-07
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device comprising: forming a first mask layer over a semiconductor layer; forming a silicon layer as a second mask layer over the first mask layer; forming a first photoresist over the second mask layer, and after exposing the first photoresist with ArF, making the first photoresist into a first photoresist pattern having a first window and a second window by developing the first photoresist; forming a first opening in the second mask layer under the first window and forming a second opening in the second mask layer under the second window, by etching the second mask layer through the first window and the second window; forming a third opening in the first mask layer under the first opening and forming a fourth opening in the first mask layer under the second opening, by etching the first mask layer through the first opening and the second opening; removing the first photoresist pattern; forming a first trench and a second trench in the semiconductor layer under the third opening and the fourth opening by etching the semiconductor layer while using the second mask layer as an etching mask; covering the first mask layer with a second photoresist pattern that covers the first trench and has a third window through which the fourth opening is exposed; and etching the second trench to a depth deeper than a depth of the first trench through the fourth opening exposed through the third window.