Patent ID: 6759337
Filing Date: 2004-07-06
Classification: H01L

Abstract:
A process for etching away a fixed thickness of silicon oxide from a region of uniform thickness of a silicon oxide layer of an integrated circuit structure on a semiconductor substrate in an etching apparatus to form a thinner silicon oxide region of uniform thickness which comprises:a) exposing a silicon oxide surface of an integrated circuit structure on a semiconductor substrate to a plasma consisting essentially of a nitrogen plasma generated by a first rf power source maintained at a power level of from about 250 watts to about 1000 watts; and b) maintaining on said semiconductor substrate, an rf bias from a second rf power source maintained at a power level of from above zero up to a power level just below a level at which sputtering of said substrate materials would commence on said semiconductor substrate during said exposure of said silicon oxide surface to said nitrogen plasma; whereby a fixed thickness of silicon oxide will be removed from said silicon oxide region of uniform thickness, leaving a silicon oxide layer having a thinner region of uniform thickness, with the silicon oxide thickness removed dependent upon the power level of said rf bias on said semiconductor substrate.