Inventors:
Ronald R. Bourassa - Colorado Springs CO
Michael R. Reeder - Colorado Springs CO
Assignee:
Inmos Corporation - Colorado Springs CO
International Classification:
H01L 21306, C03C 1500, B44C 122, C23F 102
Abstract:
A process is described for anisotropically etching semiconductor products which include a lower dielectric layer, an intermediate polysilicon layer, and an upper silicide layer such as titanium silicide. A pattern-defining layer will normally overlie the silicide layer to define target areas to be etched. In a first step, the silicide is etched through using Freon 115 chloro, pentafluoroethane (C. sub. 2 ClF. sub. 5) in a plasma etching chamber conditioned to provide a reactive ion etch. The etch is completed in the same chamber using a second gas which includes an amount of Cl. sub. 2 selected to etch anisotropically through the polysilicon layer without substantially etching the dielectric layer. Preferably, both etches occur after covering inner surfaces of the etching chamber with a material which releases molecules of the character included in the pattern-defining layer, such as Kapton, a polymide, in the disclosed example.