Fluorine free integrated process for etching aluminum including chamber dry clean

TL;DR: A fluorine-free integrated process for plasma etching aluminum lines in an integrated circuit structure including an overlying anti-reflection coating (ARC) and a dielectric layer underlying the aluminum, the process being preferably performed in a single plasma reactor is described in this article.

Abstract: A fluorine-free integrated process for plasma etching aluminum lines in an integrated circuit structure including an overlying anti-reflection coating (ARC) and a dielectric layer underlying the aluminum, the process being preferably performed in a single plasma reactor. The ARC open uses either BCl 3 /Cl 2 or Cl 2 and possibly a hydrocarbon passivating gas, preferably C 2 H 4 . The aluminum main etch preferably includes BCl 3 /Cl 2 etch and C 2 H 4 diluted with He. The dilution is particularly effective for small flow rates of C 2 H 4 . An over etch into the Ti/TiN barrier layer and part way into the underlying dielectric may use a chemistry similar to the main etch. A Cl 2 /O 2 chamber cleaning may be performed, preferably with the wafer removed from the chamber and after every wafer cycle.