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C e n t r a l R e s e a r c h L a b . , M i t s u b i s h i E l e c t r i c C o r p . , A m a g a s a k i - ABSTRACTThe gas plasma technique was applied to the etching of Si3N4, poly-Si, Si02 and the multi-layer films in fabrication of MOS-LSI.For Si3N4 film in the selective oxidation process, the so-called side-etching can be controlled from negative, zero to positive, by varying the plasma conditions. The Al-gate MOS-LSI's fabricated by this process work well and have good reliability, and their wafer yield was better than that of devices fabricated by the process using the wet-chemical etching. The gas plasma technique could give the tapered etching of poly-Si film in the Si-gate process and also smooth edges without under-cutting in the multilayer structures including the MNOS and SNOS. Si02 films could be etched successfully by the gas plasma technique, but the processing time may be too long depending on processes.