Method of making memory cell capacitor

Details Method of making memory cell capacitor Method of making memory cell capacitor

1992-11-12

1994-08-30

Thomas, Tom

Fishing, trapping, and vermin destroying

437 47, 437 60, 437919, 437977, H01L 2170

Patent

active

053428005

ABSTRACT:
A method for making a memory cell capacitor is disclosed. Steps in accordance with present invention are: (1) forming a capacitor node contact hole after making necessary elements in a semiconductor substrate by depositing an insulation layer and etching a predetermined portion of the insulating layer by a photolithographic process; (2) depositing a doped polysilicon layer, thereby making a contact for connecting the capacitor electrode and a source/drain region in the semiconductor substrate; (3) depositing a silicon nitride layer and a first silicon oxide layer, and opening a window by a photolithographic process in the first silicon nitride layer and the silicon oxide layer at a position where the capacitor storage electrode is to be formed; (4) depositing a hemispherical polysilicon layer having peaks and valleys on the exposed surfaces of the polysilicon layer, the silicon nitride layer, and the first silicon oxide layer; (5) depositing a second oxide layer and etching back the second silicon oxide layer so that it selectively remains in the valleys of the hemispherical polysilicon layer; (6) forming a plurality of polysilicon projections by dry etching the hemispherical polysilicon layer and the polysilicon layer using the remaining portions of the second silicon oxide layer and the first silicon oxide layer as a mask; (7) removing the first and second silicon oxide layers by a wet etching process; (8) depositing a polyimide layer and etching back the polyimide layer so as to expose the surface of the silicon nitride layer; and (9) forming a capacitor storage electrode by removing the silicon nitride layer by a wet etching process, etching the polysilicon layer by using the polyimide layer as a mask, and removing the polyimide layer. In step (2), the doped polysilicon layer may be deposited to a thickness of about 2000 .ANG. or more by applying a LPCVD process at a temperature of about 500.degree. C. or more.

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