PLASMA ETCHING GAS AND PLASMA ETCHING METHOD

摘要

The present invention is an etching gas that contains an unsaturated fluorinated hydrocarbon represented by CxHyFz (x = 3, 4, or 5; y + z = 2 x; and y > z) and a method for selectively etching a silicon nitride film on a silicon oxide film or silicon film using this etching gas. According to the present invention, etching of the silicon nitride film laminated onto the silicon oxide film or silicon film can be carried out with high selectivity.