MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To etch selectively only an insulating film at the base of a hole part or a groove which has a large aspect ratio by providing processes: one process to form a groove or a hole; another process to form the insulating film; a third process to etch selectively only the insulating film at the base of the groove or the hole by means of etching which is fraught with a film deposit. CONSTITUTION:Deep holes are made in a semiconductor substrate 1 by making a resist or SiO2 act as a mask and the resist is removed by plasma ashing and SiO2 is removed by wet etching. Then, an oxide Si film 2 is deposited by CVD(chemical vapor deposition). Subsequently, when etching is performed by using a CH2F2 gas as an etching gas, only oxide Si films at the bases of fine holes having each large aspect ratio (depth of the hole/diameter of the hole) are etched and films other than the oxide Si films are not etched very much. In this way, only the insulating films at the base parts of patterns having large aspect ratios are etched selectively. Steps of respective processes are thus simplified.