Patent ID: 6071798
Filing Date: 2000-06-06
Classification: H01L

Abstract:
A method for fabricating buried contacts comprising the steps of:a) forming isolation structures on a silicon substrate;b) forming a first insulating layer over said silicon substrate;c) forming a first conductive layer over said first insulating layer;d) forming a photoresist mask over said first insulating layer; said photoresist mask having a buried contact opening;e) etching said first conductive layer and said first insulating layer through said buried contact opening;f) descumming said photoresist mask; thereby forming an expanded opening; said expanded opening forming an exposed ring of said first conductive layer with subjacent first insulating layer;g) implanting impurity ions through said expanded opening forming a buried contact region; said impurity ions being implanted at a sufficient energy level to penetrate said exposed ring of said first conductive layer and said first insulating layer;h) removing said photoresist mask;i) forming a second conductive layer over said first conductive layer and over exposed region of said buried contact region;j) forming a polycide layer over said second conductive layer;k) patterning said polycide layer, said second conductive layer, said first conductive layer and said first insulating layer to form a second opening; said second opening defines a gate structure and a contact structure having sidewalls; said second opening parially overlaps said extended buried contact region;l) implanting ions through said second opening to form lightly doped source/drain regions;m) forming spacers on the sidewalls of said gate structure and said contact structure;n) implanting ions to form source/drain structures.