Patent ID: 6673719
Filing Date: 2004-01-06
Classification: H01L

Abstract:
A method for etching using a multilevel hard mask, comprising:providing a substrate having a multilayer structure thereon; forming a BPSG layer on the multilayer structure; forming a masking material layer on the BPSG layer, wherein the masking material layer has a high selective etching ratio for the BPSG layer; forming a patterned photoresist layer on the masking material layer; transferring a pattern of the patterned photoresist layer to the masking material layer; transferring the pattern of the masking material layer to the BPSG layer by etching under the conditions of the high etching ratio of the BPSG layer to the masking material layer; and using the masking material layer and the BPSG layer as a multilevel hard mask to physically etch the multilayer structure to form a trench therein.