Patents Represented by Attorney S. Wilkinson

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  • Process for plasma etching polysilicon to produce rounded profile islands
    Patent number: 4718973
    Abstract: In a silicon integrated circuit manufacturing process a layer of polysilicon is ion implanted with an n-type dopant and etched through a mask with a fluorine:chlorine mixture. The etchant undercuts at the mask to an extent dependent on the ratio of chlorine:fluorine and on the dopant level. By appropriately selecting that ratio and dopant level, polysilicon islands having a rounded profile can be achieved, this being most efficacious for subsequent deposition onto the polysilicon.
    Type: Grant
    Filed: May 19, 1986
    Date of Patent: January 12, 1988
    Assignee: Northern Telecom Limited
    Inventors: Thomas Abraham, Robert E. Theriault