DEPROCESSING METHOD FOR ANALYSIS OF DEFECT OF SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To make it possible to detect an alignment position and a failure in contact with a polysilicon contact clearly, by carrying out an etching step in a way that lower ends of a bit-line polysilicon film and a storage-node polysilicon film of a capacitor remain on a silicon substrate while a device separation film is generated using a wet solution containing a hydrogen fluoride. SOLUTION: A bit-line polysilicon film 28 and a storage-node polysilicon film 30 are put in contact with a source/drain region 26 on a silicon substrate 21. A plasma dry etching step for each upper part of the bit-line polysilicon film 28 and polysilicon films 30 and 32 that constitute a wing part of a capacitor is carried out. After that, a wet etching step with a solution containing hydrogen fluoride is carried out in a way that lower edge portions 28a and 30a of the bit-line polysilicon film 28 and the storage-node polysilicon film 30 remain on the polysilicon substrate 21 while a field oxide film 22 is generated.