Novel high aspect ratio aluminum plug for logic/DRAM LSIs using polysilicon-aluminum substitute (PAS)

This paper describes a polysilicon-aluminum substitute (PAS) technique for single-crystalline aluminum plugs with aspect ratios of over 7 used for subquartermicron logic/DRAM LSIs. A via hole was filled with polysilicon by CVD, and aluminum was deposited on the planarized polysilicon plug. An aluminum plug was substituted for the polysilicon by annealing. We filled via holes having a minimum diameter of 0.175 /spl mu/m and a depth of 1.7 /spl mu/mn (an aspect ratio of about 10) with aluminum.