Semiconductor device having an improved contact structure and a manufacturing method thereof

摘要

There is described formation of a contact hole without involvement of damage to an etching stopper film and deterioration of electric characteristics, achieved by means of a self-alignment method. An interlayer oxide film is etched through an opening of a resist mask, and by means of plasma etching through use of a processing gas comprising a mixture of a rare gas and a CF-based gas, thereby tapering a shoulder of the silicon nitride film. Alternatively, a silicon oxide film and a silicon nitride film are continually etched through an opening of the resist mask, by means of plasma etching through use of a CH2F2 gas added to a mixed gas including a rare gas and a C4F8 gas.