Tungsten liner process for simultaneous formation of integral contact studs and interconnect lines.

摘要

Tungsten studs and tungsten lined studs that make low resistance thermally stable ohmic or Schottky contacts to active devices on a semiconductor substrate are made by first defining a triplex metallurgical structure. The triplex metallurgical structure of the present invention includes an ohmic layer (6) of titanium, a barrier layer (7) e.g. Cr-CrOx and a sacrificial layer (8), e.g. Al-Cu. Then, a blanket layer of insulator (9) is deposited and polished, for planarization, until the stud metallurgy is exposed. The sacrificial layer is then etched out, leaving holes self-aligned to the contacts and to the ohmic and the barrier layers. A thin layer of titanium (10) is deposited and appropriately etched out, to leave metal only at the strid location. Finally, a blanket layer of CVD tungsten (12) is then deposited and the substrate is polished for planarization. The metal contact studs can be simultaneously formed with patterned interconnection lines which are self-aligned to each other and also to the contact studs.