MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To selectively etch a CVD oxide film on a thermal oxide film by using an NF4F solution properly diluted with water. CONSTITUTION:A thermal oxide film is thinly formed on a semiconductor substrate to apply a resist mask by placing a CVD oxide film on the thermal oxide film and a photoetching is applied by a solution dilluted NH4F with H2O. The speed ratio of the photoetching for the NH4F solution is about CVD oxide film: Thermal oxide film = 4.5:1. Therefore, control is difficult for a thin thermal oxide film due to a high etching speed. A slow photoetching speed sill be attained by diluting the NH4F solution with water. And easy control will be possible as the CVD oxide film only will easily be selected and etched.