Method and apparatus for minimizing plasma destabilization within a semiconductor wafer processing system
First Claim
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1. Apparatus for retaining a substrate, such as a semiconductor wafer, in a semiconductor processing system comprising:
- an electrostatic chuck having an electrode embedded beneath a substrate support surface;
a power supply, coupled to said electrode of said electrostatic chuck, for applying a chucking voltage to said electrode, where said substrate is retained by a negative potential difference between said substrate and said electrostatic chuck while said substrate is exposed to a plasma for purposes of plasma processing the substrate.
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Abstract
A method and apparatus for retaining a substrate, such as a semiconductor wafer, upon an electrostatic chuck within a semiconductor wafer processing system. Specifically, the apparatus contains high voltage, DC power supply that is capable of both sourcing and sinking current at any polarity of output voltage level. This power supply is coupled to at least one electrode of an electrostatic chuck. Consequently, the power supply can be used to dynamically control the chucking voltage to apply a negative potential difference between said wafer and chuck.
44 Citations
15 Claims
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1. Apparatus for retaining a substrate, such as a semiconductor wafer, in a semiconductor processing system comprising:
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an electrostatic chuck having an electrode embedded beneath a substrate support surface;
a power supply, coupled to said electrode of said electrostatic chuck, for applying a chucking voltage to said electrode, where said substrate is retained by a negative potential difference between said substrate and said electrostatic chuck while said substrate is exposed to a plasma for purposes of plasma processing the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for retaining a substrate, such as a semiconductor wafer, comprising the steps of:
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supporting the substrate on a substrate support surface of an electrostatic chuck containing a chucking electrode; and
applying a variable DC chucking voltage to said chucking electrode to electrostatically retain the substrate by creating a negative potential difference between the substrate and the electrostatic chuck while said substrate is exposed to a plasma for purposes of plasma processing the substrate. - View Dependent Claims (11, 12, 13, 14, 15)
further measuring an indicia of optimal chucking; and
controlling said variable DC chucking voltage in response to said indicia.
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12. The method of claim 11 wherein said indicia is a potential difference between an electrode and the substrate and said chucking voltage is controlled to achieve a constant potential difference.
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13. The method of claim 12 wherein said potential difference is indicia of a chucking force between the substrate and the electrostatic chuck.
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14. The method of claim 11 wherein said indicia is a leakage current value flowing into the electrostatic chuck and said chucking voltage is controlled to achieve a constant leakage current.
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15. The method of claim 12 wherein said potential difference is estimated by measuring a peak-to-peak or peak RF voltage applied to a cathode electrode within said process chamber by an RF supply.
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