JPS6425551A - Semiconductor device - Google Patents

Abstract

PURPOSE:To perform etching for providing a tapered part on a contact hole with good controllability and to prevent short circuits between a lower electrode or a wiring layer and an upper wiring layer, by contriving the constitution of an interlayer insulating film between the lower electrode layer or the wiring layer and the upper wiring layer. CONSTITUTION:Polycrystalline silicon layers 12 and 13 are formed on a silicon substrate 10. The outer parts of the layers are surrounded with a thermal oxide film 14. An SiO2 film 15 including 1X10<20>cm<-3> or less of boron is deposited on the film 14. Then, an SiO2 film 16 is deposited. An SiO2 film including 1X10<20>cm<-3> or more of phosphorus is further deposited on the film 16. A contact hole is further patterned, and etching is performed so as to provided a tapered part. At this time, the SiO2 film becomes a stopper for etching. Therefore, the SiO2 film 16 as the etching stopper is present between the SiO2 films 15 and 17. Thus the controllability for etching when the tapered part is provided on the contact hole is improved. The occurrence of short circuit faults due to the approaching of the contact hole and a gate layer by excessive etching is prevented.