METHOD FOR MANUFACTURING TRENCH REDUCING STRESS CONCENTRATION PHENOMENON OF BOTTOM SURFACE OF TRENCH

摘要

PURPOSE: A method for manufacturing a trench reducing a stress concentration phenomenon of a bottom surface of the trench is provided to control a stress concentration phenomenon of a lower surface of the trench by improving a trench etching profile, and to improve reliability by controlling a defect such as dislocation. CONSTITUTION: A silicon substrate(10) is selectively etched to form a trench by using a predetermined trench mask pattern. An etching process is performed on a condition that polymer is generated a lot in the beginning of the etching process, so that an active region in an upper portion of the trench has a rounding profile of a convex surface. An etching process is performed on a condition that polymer is controlled in the halfway of the etching process, to form a trench sidewall profile gradually approaching the vertical. An etching process is performed on a condition that polymer is generated a lot in the end of the etching process, so that an active region in a lower portion of the trench has a rounding profile of a concave surface.