Semiconductor device manufacturing method for making semiconductor device e.g. memory module such as dynamic random access memory (DRAM), involves performing etching processes to form deep trench structure and selectively corrode mask layer

摘要

The method involves forming a hard mask on a layer (2) to form a mask layer (1) before forming a deep trench structure, in which the mask layer includes two layers (11,12) made of selected corrosive materials. The deep trench structure is formed on the layer by performing first etching process. The first etching process is interrupted at one time to corrode the highest layer (11) of the mask layer selectively in relation to the other layer (12) by performing second etching process. The first etching process is then continued to form the deep trench structure with the new highest layer (12).