METHOD OF ETCHING SiN/Ir/TaN OR SiN/Ir/Ti STACK USING ALUMINUM HARD MASK

摘要

PROBLEM TO BE SOLVED: To provide a highly selective etching technique in an iridium and silicon nitride containing structure. SOLUTION: A method of etching includes a step of depositing a first etch stop layer 36; a step of forming an iridium lower electrode layer 38; a step of depositing an SiN layer 40; a step of depositing and patterning an aluminum hard mask 42; a step of etching a non-patterned SiN layer 40 with a SiN selective etchant, and a step of stopping at the level of the iridium bottom electrode layer. Further, the method includes a step of etching the first etch stop layer 36 with a second selective etchant; a step of depositing an oxide layer and CMP the oxide layer to the level of the remaining SiN layer; a step of wet etching the SiN layer to form a trench; and a step of depositing a layer of ferroelectric material in the trench formed by removal of the SiN layer. COPYRIGHT: (C)2005,JPO&NCIPI