METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A fabrication method of semiconductor devices is provided to improve an etch profile of a DTI(Deep Trench Isolation) by removing tip points generated at bottom corners of a trench. CONSTITUTION: A deep trench is formed in a desired portion of a semiconductor substrate(21) by performing a first etch processing at atmosphere of low polymer formation gases. By performing a second etch processing at atmosphere of high polymer formation gases so as to remove tip portions generated at bottom corners of the deep trench, a trench(22) having an improved etch profile is formed. Mixed gases of HBr and CF4 are used as the polymer formation gas.