Abstract: A method and system for etching features in a substrate, whereby silicon oxide or silicon nitride or both are etched with high selectivity relative to silicon. In one embodiment, the process chemistry utilized to achieve high selectivity includes trifluoromethane (CHF3), difluoromethane (CH2F2), an oxygen containing gas, such as O2, and an optional inert gas, such as argon.

Abstract: There is provided an etching method and a plasma etching apparatus capable of taking a large etching selection ratio and of forming a hole having an appropriate shape. When etching an etching target film 204 by using an organic film 202 having a predetermined pattern as a mask, processing gas is introduced into an airtight processing container 104. There are provided a high frequency power source 122 of 40 MHz and a high frequency power source 128 of 3.2 MHz, by which two different kinds of high frequency powers are applied to a lower electrode 106. The power of each high frequency power is properly combined, thereby executing the etching process by using low plasma electron density Ne and high self-bias voltage Vdc which are generated by high frequency power.