Fluorine free integrated process for etching aluminum including chamber dry clean

摘要

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 BCl3/Cl2 or Cl2 and possibly a hydrocarbon passivating gas, preferably C2H4. The aluminum main etch preferably includes BCl3/Cl2 etch and C2H4 diluted with He. The dilution is particularly effective for small flow rates of C2H4. 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 Cl2/O2 chamber cleaning may be performed, preferably with the wafer removed from the chamber and after every wafer cycle.