Controlling plasma particulates by contouring the plasma sheath using materials of differing RF impedances
AssigneeApplied Materials, Inc.
InventorsRobert J. Steger, Charles S. Rhoades, Anand Gupta
Life of this patent
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Abstract
A plasma processing apparatus including a wafer supporting pedestal which is designed to reduce particle trapping phenomena. In a region of the pedestal surface which surrounds or abuts the wafer, the pedestal has a permittivity which is substantially equal to or greater than that of the wafer surface. As a result, the sheath boundary is reshaped to reduce particle trapping.
Claims4
A plasma processing apparatus for processing a wafer surface comprising:
- a) a vacuum chamber;
- b) a pedestal including a pedestal cover within said vacuum chamber, said pedestal having a surface for supporting said wafer;
- and
- c) an RF electrical source connected between said pedestal surface and said chamber to generate a plasma within said chamber in a region above said wafer surface;
- wherein, in a region of said pedestal which adjoins an edge of said wafer, said pedestal surface has a permittivity equal to or greater than a permittivity of said wafer surface, and said pedestal cover further comprises a shadow ring which extends above said wafer surface, said shadow ring having a permittivity equal to or greater than said permittivity of said wafer surface.
A plasma processing apparatus for processing a wafer surface comprising:
- a) a vacuum chamber;
- b) a pedestal including a pedestal cover within said vacuum chamber, said pedestal having a surface for supporting said wafer;
- and
- c) an RF electrical source connected between said pedestal surface and said chamber to generate a plasma within said chamber in a region above said wafer surface;
- wherein, in a region of said pedestal which adjoins an edge of said wafer, said pedestal surface has a permittivity equal to or greater than a permittivity of said wafer surface, and said pedestal cover further comprises an epitaxial layer of inert material overlying said pedestal surface having a permittivity equal to or greater than said permittivity of said wafer surface.
A method of processing a wafer surface comprising:
- a) supporting said wafer on a surface of a pedestal including a pedestal cover in a vacuum chamber;
- and
- b) applying an RF electrical source between said pedestal surface and said chamber to generate a plasma within said chamber in an area above said wafer surface;
- wherein, in a region of said pedestal which adjoins an edge of said wafer, said pedestal surface has a permittivity equal to or greater than a permittivity of said wafer surface, and said pedestal cover further comprises a shadow ting which extends above said wafer surface, said shadow ring having a permittivity equal to or greater than said permittivity of said wafer surface.
A method of processing a wafer surface comprising:
- a) supporting said wafer on a surface of a pedestal including a pedestal cover in a vacuum chamber;
- and
- b) applying an RF electrical source between said pedestal surface and said chamber to generate a plasma within said chamber in an area above said wafer surface;
- wherein, in a region of said pedestal which adjoins an edge of said wafer, said pedestal surface has a permittivity equal to or greater than a permittivity of said wafer surface, and said pedestal cover further comprises an epitaxial layer of inert material overlying said pedestal surface having a permittivity equal to or greater than said permittivity of said wafer surface.
Dependencies are inferred from the claim text.