Patent ID: 6303272
Filing Date: 2001-10-16
Classification: H01L

Abstract:
A method for forming self-aligned wiring trenches and contact holes in a semiconductor substrate comprising the steps of:(A) forming a lower dielectric layer over the substrate;(B) forming an upper layer of hard mask material over the lower dielectric layer;(C) forming a first photoresist layer over the upper hard mask material layer,(D) exposing the first photoresist layer through a first mask to form a first pattern for wiring;(E) developing the exposed first photoresist layer to produce openings for wiring having a first width in the first patterned photoresist layer to form a wiring line etch mask;(F) selectively etching the upper layer of hard mask material through the patterned photoresist etch mask to form a first, patterned wiring trench hard material etch mask;(G) stripping away the first photoresist wiring line etch mask;(H) forming a second photoresist layer that is separate from the first patterned photoresist layer over the wiring trench hard material etch mask;(I) exposing the second, separate photoresist layer through a second mask to form a second pattern for contacts wherein two edges of the wiring trench hard material etch mask are employed in conjunction with two edges of the second photoresist layer to jointly define a contact hole pattern;(J) developing the exposed second patterned photoresist layer to produce elongated rectangular shaped openings having a second width in the second photoresist layer to form a contact hole etch mask;(K) selectively etching the lower dielectric layer through the hard material wiring trench etch mask and through the second photoresist contact hole etch mask to form self-aligned wiring line trenches and elongated, rectangular contact holes in the lower, dielectric layer, wherein the rectangular contact holes have a width determined by the width of the openings in the first patterned photoresist layer wiring line etch mask and the width of the openings in the second photoresist layer.