Clamped showerhead electrode assembly
First Claim
1. A showerhead electrode assembly wherein the showerhead electrode comprises an upper electrode of a capacitively coupled plasma processing chamber, comprising:
- a backing plate having gas passages extending between upper and lower faces thereof;
a clamp ring having an inwardly extending flange and stepped bores configured to receive fasteners which engage threaded openings in the lower face of the backing plate;
the showerhead electrode comprising a circular plate having a plasma exposed surface on a lower face thereof, a mounting surface on an upper face thereof, the inner face including a step at an outer periphery of the plate, the step configured to mate with the inwardly extending flange of the clamp ring, the plate including process gas outlets arranged in a pattern matching the gas passages in the backing plate; and
a compression ring between opposed surfaces of the clamp ring flange and the step of the showerhead electrode;
jackscrews mounted in the lower face of the backing plate, the jackscrews being rotatable to move annular flanges on the jackscrews against the upper face of the inner electrode to separate the inner electrode from the backing plate during disassembly of the inner electrode.
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Accused Products
Abstract
An electrode assembly for a plasma reaction chamber used in semiconductor substrate processing. The assembly includes an upper showerhead electrode which includes an inner electrode mechanically attached to a backing plate by a clamp ring and an outer electrode attached to the backing plate by a series of spaced apart cam locks. A guard ring surrounds the backing plate and is movable to positions at which openings in the guard ring align with openings in the backing plate so that the cam locks can be rotated with a tool to release cam pins extending upward from the upper face of the outer electrode. To compensate for differential thermal expansion, the clamp ring can include expansion joins at spaced locations which allow the clamp ring to absorb thermal stresses.
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Citations
21 Claims
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1. A showerhead electrode assembly wherein the showerhead electrode comprises an upper electrode of a capacitively coupled plasma processing chamber, comprising:
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a backing plate having gas passages extending between upper and lower faces thereof; a clamp ring having an inwardly extending flange and stepped bores configured to receive fasteners which engage threaded openings in the lower face of the backing plate; the showerhead electrode comprising a circular plate having a plasma exposed surface on a lower face thereof, a mounting surface on an upper face thereof, the inner face including a step at an outer periphery of the plate, the step configured to mate with the inwardly extending flange of the clamp ring, the plate including process gas outlets arranged in a pattern matching the gas passages in the backing plate; and a compression ring between opposed surfaces of the clamp ring flange and the step of the showerhead electrode; jackscrews mounted in the lower face of the backing plate, the jackscrews being rotatable to move annular flanges on the jackscrews against the upper face of the inner electrode to separate the inner electrode from the backing plate during disassembly of the inner electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An outer electrode of a showerhead electrode assembly wherein the outer electrode surround an inner electrode and the showerhead electrode comprises an upper electrode of a capacitively coupled plasma processing chamber, comprising:
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an annular plate having a plasma exposed surface on a lower face thereof and a mounting surface on an upper face thereof, the upper face including a planar annular surface between an upper inner step and an upper outer step, the plasma exposed surface including inner and outer inclined surfaces; a plurality of circumferentially spaced apart pockets in the planar annular surface configured to receive locking pins therein adapted to clamp the outer electrode to a backing plate of the showerhead electrode assembly. - View Dependent Claims (9, 10)
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11. A showerhead electrode assembly of a capacitively coupled plasma processing chamber, comprising:
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a thermal control plate supported by a temperature controlled top wall of the plasma processing chamber, the thermal control plate having a diameter larger than a wafer to be processed in plasma processing chamber and including at least one gas plenum in a lower face thereof; a backing plate supported by the thermal control plate, the backing plate having a diameter smaller than the thermal control plate, gas passages extending vertically therethrough and communicating with the at least one gas plenum and rotatable cam locks in bores extending horizontally into an outer periphery of the backing plate; a guard ring surrounding the backing plate, the guard ring including at least one horizontally extending access bore passing through the guard ring, the guard ring being rotatable around the backing plate to align the access bore with at least one of the cam locks; an inner electrode having gas passages extending vertically therethrough in fluid communication with the gas passages in the backing plate, an outer periphery of the inner electrode including inner and outer steps, the outer step being located between the inner step and a surface of the inner electrode facing the backing plate; a clamp ring having an inner flange overlying the outer step of the inner electrode with an optional compression ring therebetween, the clamp ring including vertically extending stepped openings, the stepped openings being aligned with threaded holes in the backing plate and fasteners in the stepped openings attaching the clamp ring to the backing plate; and an outer electrode surrounding the inner electrode and including vertically extending locking pins which engage the cam locks, the outer electrode supporting the guard ring and being removable by releasing the locking pins from the cam locks. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification