Structural etching of semiconductor - using brief treatment in tetra:fluoromethane plasma before etching, increasing adhesion of photoresist mask

摘要

In structural etching of semiconductors involving coating the semiconductor surface with a photoresist, exposing and developing this and etching, the semiconductor is placed in a CF4 plasma briefly after exposure and before etching. This treatment is pref. effected for 1-3 min in a plama at ca. 0.5-1 torr. Used esp. for deep etching using negative lacquers for masking, esp. for etching mesa grooves in epitaxial base transistors. Process is simplified and the adhesion of the photoresist to the substrate is improved.