Element isolation method for semiconductor devices including etching implanted region under said spacer to form a stepped trench structure

摘要

An element isolation method, in particular, a shallow trench isolation (STI) method for semiconductor devices is disclosed in which a trench is formed to have a stepped structure shaped in such a fashion that it has a smaller width at its lower portion than at its upper portion. This stepped trench structure, which includes at least one step, is capable of obtaining an increased metal contact margin, thereby preventing metal contacts from being short-circuited with wells due to a misalignment thereof.