29 June 1984 Anisotropic Plasma Etching Of Polysilicon With 100:1 Selectivity Over Thermal Oxide
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Abstract
A plasma etching process for polycrystalline silicon with an etch ratio of 100:1 to thermal oxide has been developed. Sulfur hexafluoride containing 9% chlorine has been excited, at a rf power of 150 watts and at a total pressure of .100 Torr (13.3 Pa), to etch polysilicon. A decrease in the etch ratio of silicon to oxide with increasing overetch time has been observed. The etch profiles were nearly vertical and the vertical to lateral etch rate ratio was nearly 8:1. A model consistent with the experimental observations has been proposed. The process has been used successfully to clear polysilicon over steps of a height of approximately 0.75 pm without disturbing the structural integrity. Owing to its high selectivity to oxide and good linewidth control, the process can be used for fabricating VLSI circuits with thinner gate oxides.
© (1984) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
D.Bhogeswara Rao "Anisotropic Plasma Etching Of Polysilicon With 100:1 Selectivity Over Thermal Oxide", Proc. SPIE 0470, Optical Microlithography III: Technology for the Next Decade, (29 June 1984); doi: 10.1117/12.941882; https://doi.org/10.1117/12.941882
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