REDUCTION METHOD OF NOTCHING PRODUCED IN REACTIVE ION ETCHING

摘要

PURPOSE: A method for reducing a notching, namely, an unnecessary lateral etching at a lower part of a silicon layer, is provided when reactive ion etching is performed to penetrate the silicon layer in a structure made up of the silicon layer, and insulating layer and a silicon substrate. CONSTITUTION: The insulating layer(200) is formed on the silicon substrate(100) and patterned to have trenches(210) therein. The silicon layer(300) is then deposited on the patterned insulating layer(200) while filling the trenches(210). Next, the silicon layer(300) is selectively etched by reactive ion etching to form etched portions(310) to which the trenches(210) correspond. Due to a higher etch rate of a wide opening(306) compared with a narrow opening(304), the silicon layer(300) in the trenches(210) as well as the wide opening(306) is removed while the silicon layer(300) in the narrow opening(304). Therefore, a conventional notching caused by overetching in the wide opening(306) is reduced.