Electrically floating shield in a plasma reactor
First Claim
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1. A PVD reactor, comprising:
- a reactor chamber having at least one generally inwardly concave side wall;
a target having a generally planar surface comprising a target material disposed in said chamber;
a support disposed in said chamber capable of supporting a substrate in opposition to said target along a chamber axis, said at least one side wall of said chamber extending generally between said target and said support;
a DC electrical power source for electrically biasing said target at a negative biasing voltage to create a plasma in said chamber;
an electrically floating shield installed in said chamber and having a portion extending in a direction along said chamber axis between said plasma and said at least one wall to protect said wall from sputter deposition; and
a second shield held at a predetermined potential higher than said negative biasing voltage and installed in said chamber between said electrically floating shield and said support to act as an anode with respect to said target.
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Abstract
In a plasma reactor, especially one intended for physical vapor deposition (PVD) onto semiconductor substrates, a shield disposed in front of the chamber walls between the PVD target and the substrates to protect the chamber walls. According to the invention, the shield is left electrically floating so that electrically charged ions and electrons emanating from the plasma or target and impinging upon the shield charge it to the point that the electrical flux is repelled.
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Citations
20 Claims
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1. A PVD reactor, comprising:
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a reactor chamber having at least one generally inwardly concave side wall; a target having a generally planar surface comprising a target material disposed in said chamber; a support disposed in said chamber capable of supporting a substrate in opposition to said target along a chamber axis, said at least one side wall of said chamber extending generally between said target and said support; a DC electrical power source for electrically biasing said target at a negative biasing voltage to create a plasma in said chamber; an electrically floating shield installed in said chamber and having a portion extending in a direction along said chamber axis between said plasma and said at least one wall to protect said wall from sputter deposition; and a second shield held at a predetermined potential higher than said negative biasing voltage and installed in said chamber between said electrically floating shield and said support to act as an anode with respect to said target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A PVD reactor, comprising:
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a chamber wall; a first electrically insulating member disposed on said wall; a target assembly disposed on said first insulating member and including a substantially planar target facing downwardly toward a substrate holder; a first shield member having a rim portion disposed on a radially inwardly extending ledge of said chamber wall and a skirt portion extending downwardly from said target; a second electrically insulating member disposed on said first shield member; and a second shield member disposed on said second insulating member and extending downwardly from a point above a bottom portion of said target and spaced from said target and said chamber wall. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A PVD reactor, comprising:
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a metal chamber wall having an inwardly extending ledge; a first shield member having a rim portion resting on said ledge and a skirt portion extending in a first direction substantially parallel to said chamber wall; a first electrically insulating member resting on said first shield member; a sputtering target assembly including a sputtering target; a second electrically insulating member supporting said target assembly on said chamber wall; and a second shield member resting on said first insulating member, separated from said chamber wall, and interposed between said target and said second electrically insulating member. - View Dependent Claims (19, 20)
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Specification