Plasma generating apparatus employing capacitive shielding and process for using such apparatus
OwnerWayne L. Johnsoninventor
Life of this patent
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Abstract
A plasma generating apparatus includes a plasma containing region and an R.F. coil for generating R.F. electric fields within the plasma region for creating a plasma from a gas flowed through the region. A capacitive shield is disposed between the coil and the plasma region for limiting the amount of capacitive coupling while not completely eliminating it, between the R.F. coil and the plasma region. The shield can include a means for varying the shielding effect thereof during processes employing the plasma.
Claims12
A plasma discharge apparatus including a plasma containing region, an R.F. coil for generating electric fields within said region, a capacitive shield of a non-magnetic electrically conductive material disposed between said region and said coil, said shield reducing the capacitive coupling between said coil and said region from a first value that would exist in the absence of said shield while allowing a capacitive coupling between said coil and said region equal to at least 1% of said first value, and means for varying the exposure of said coil through said shield for varying the capacitive coupling between said shield and said region to values in excess of said at least 1% of said first value.
A plasma discharge apparatus including a plasma containing region, an R.F. coil for generating electric fields within said region, and a capacitive shield of a non-magnetic electrically conductive material disposed between said region and said coil, said shield reducing the capacitive coupling between said coil and said region from a first value that would exist in the absence of said shield while allowing a capacitive coupling between said coil and said region equal to at least 1% of said first value, and including a hollow tube enclosing said region, one end of said tube being closed by a generally flat plate, said shield comprising a plate-like member disposed adjacent to said flat plate, and said coil comprising a planar spiral.
A plasma discharge apparatus including a plasma containing region, an R.F. coil for generating electric fields within said region, and a capacitive shield of a non-magnetic electrically conductive material disposed between said region and said coil, said shield reducing the capacitive coupling between said coil and said region from a first value that would exist in the absence of said shield while allowing a capacitive coupling between said coil and said region equal to at least 1% of said first value, said shield comprising a hollow cylinder and said coil comprising a helix concentric with said shield, said shield capacitively shielding a first portion of the length of said helix from said region, and said helix having a second portion extending axially beyond an end of said shield and being capacitively exposed to said region.
A plasma discharge apparatus including a plasma containing region, an R.F. coil for generating electric fields within said region, a capacitive shield of non-magnetic electrically conductive material disposed between said region and said coil, said shield reducing the capacitive coupling between said coil and said region from a first value that would exist in the absence of said shield while allowing a capacitive coupling between said coil and said region equal to at least 1% of said first value, and said shield including more than two openings therethrough for allowing said capacitive coupling between said coil and said region.
Dependencies are inferred from the claim text.