H ELECTRICITY
H01 ELECTRIC ELEMENTS
H01L SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
H01L21/00 Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
H01L21/02 Manufacture or treatment of semiconductor devices or of parts thereof
H01L21/04 the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
H01L21/18 the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
H01L21/30 Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
H01L21/31 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
H01L21/3105 After-treatment
H01L21/311 Etching the insulating layers; by chemical or physical means
H01L21/31105 Etching inorganic layers