The development of a polysilicon dry etch process that would result in anisotropic etch profiles as well as high selectivity to photoresist and silicon dioxide has been studied. It was found that decreasing the amount of fluorine (SF6) in the plasma significantly increased the polysilicon etch rate while only increasing the etch rate of silicon dioxide slightly. Two optimal processes were found: One that emphasized anisotropy (70% SF6 flow, 90mTorr pressure, and 200W RF power) and one that emphasized Si02 selectivity (70% SF6 flow, 23OmTorr pressure, and 200W RF power).
"Development of an Anisotropic, Selective Polycrystalline Silicon Dry Etch Process,"
Journal of the Microelectronic Engineering Conference: Vol. 10
, Article 9.
Available at: http://scholarworks.rit.edu/ritamec/vol10/iss1/9