~ process for etching aluminum was developed for a Plasmatrac 2406 Reactive Ion Etcher. The etch gases used were a mixture of silicon tetrachioride (SiC14) and helium (He). ~ SiC14 flow of 35 sccm and He flow of 48 sccm at a chamber pressure of 100 mT and power of 150 watts resulted in an average aluminum etch rate of 1450 Angstroms per minute. Resulting selectivities ratios were 3.2:1 for aluminum to resist, and 30:1 for aluminum to the underlying oxide. The etch uniformity was approximately 27~ and etching of aluminum lines less than 2 microns resulted in an anisotropic etch profile of approximately 75 degrees. This is a working process but further work is required to increase the aluminum etch rate and improve the selectivity to resist.
Hosein, Asadd M.
"Reactive Ion Etching of Aluminum on the Plasmatrac 2406,"
Journal of the Microelectronic Engineering Conference: Vol. 4
, Article 21.
Available at: http://scholarworks.rit.edu/ritamec/vol4/iss1/21