Conformal pure and doped aluminum coatings and a methodology and

Abstract

The present invention relates to a process and apparatus for the formation of conformal pure aluminum and doped aluminum coatings on a patterned substrate. It is directed to the use of low temperature thermal and plasma-promoted chemical vapor deposition techniques with biased substrate to provide conformal layers and bilayers comprised of pure Al and/or doped Al (e.g., Al with 0.5 at % copper) on semiconductor device substrates with patterned holes, vias, and trenches with aggressive aspect ratios (hole depth/hole width ratios). The use of the plasma-promoted CVD (PPCVD) process, which employs low plasma power densities, allows the growth of aluminum films with the smooth surface morphology and small grain size necessary for ULSI applications, while substrate bias provides superior coverage and complete aluminum fill of features intrinsic in microelectronic device manufacture. Aluminum doping is achieved by in-situ deposition by PPCVD of sequential bilayers of Al and Cu followed by in-situ annealing, or in-situ simultaneous PPCVD deposition of copper-doped aluminum.