Plasma reactor
First Claim
1. A plasma etch reactor comprising:
- an etch chamber defined at least in part by cylindrical sidewalls;
a plasma source in communication with said etch chamber for generating and supplying a plasma to said etch chamber;
a wafer chuck for receiving a wafer, the wafer chuck disposed concentrically between the cylindrical sidewalls;
a radio-frequency voltage source electrically coupled between the wafer chuck and the cylindrical sidewalls of the etch chamber to provide an electric field in the etch chamber between a wafer placed on the wafer chuck and said sidewalls; and
a dielectric ring comprising an upright inner radial wall disposed in adjacent, concentric and external relationship to a circumference of a wafer placed on the wafer chuck, and extending substantially perpendicularly above a plane defined by an upper surface of the wafer.
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Accused Products
Abstract
This invention is a hardware modification which permits greater uniformity of etching to be achieved in a high-density-source plasma reactor (i.e., one which uses a remote source to generate a plasma, and which also uses high-frequency bias power on the wafer chuck). The invention addresses the uniformity problem which arises as the result of nonuniform power coupling between the wafer and the walls of the etch chamber. The solution to greatly mitigate the nonuniformity problem is to increase the impedance between the wafer and the chamber walls. This may be accomplished by placing a cylindrical dielectric wall around the wafer. Quartz is a dielectric material that is ideal for the cylindrical wall if silicon is to be etched selectively with respect to silicon dioxide, as quartz it is virtually inert under such conditions.
93 Citations
9 Claims
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1. A plasma etch reactor comprising:
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an etch chamber defined at least in part by cylindrical sidewalls;
a plasma source in communication with said etch chamber for generating and supplying a plasma to said etch chamber;
a wafer chuck for receiving a wafer, the wafer chuck disposed concentrically between the cylindrical sidewalls;
a radio-frequency voltage source electrically coupled between the wafer chuck and the cylindrical sidewalls of the etch chamber to provide an electric field in the etch chamber between a wafer placed on the wafer chuck and said sidewalls; and
a dielectric ring comprising an upright inner radial wall disposed in adjacent, concentric and external relationship to a circumference of a wafer placed on the wafer chuck, and extending substantially perpendicularly above a plane defined by an upper surface of the wafer. - View Dependent Claims (2, 3)
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4. A plasma reactor comprising:
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a housing comprising cylindrical sidewalls and first and second interior regions, said second interior region between said cylindrical sidewalls, said first interior region in fluid communication with said second interior region;
a wafer chuck having a first surface for receiving a wafer, said wafer chuck disposed coaxially between said cylindrical sidewalls;
at least one gas manifold coupled to said housing to supply at least one gas to within said housing;
a first energy source functionally configured to supply first energy to said first interior region for exciting said gas and generating a plasma within said first interior region;
a second energy source electrically coupled between said wafer chuck as a first electrode and said cylindrical sidewalls of said housing as a second electrode, and operable to provide electromagnetic fields therebetween to accelerate ions of plasma within said second interior region; and
a cylindrical dielectric ring comprising an inner radial wall that extends above said wafer chuck and in concentric relationship relative to a wafer upon said wafer chuck, said inner radial wall having a height that extends substantially perpendicularly above a plane defined by an upper surface of said wafer. - View Dependent Claims (5, 6, 7, 8, 9)
wherein said housing includes a ceiling over said first interior region; - and
wherein said gas manifold is coupled to said ceiling, enabling supply of said gas to said housing proximate said first interior region.
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7. A plasma reactor according to claim 4, wherein said first energy source comprises one of a helicon source, or an electron cyclotron resonance (ECR) source.
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8. A plasma reactor according to claim 7, wherein said second energy source provides a radio-frequency voltage bias to said wafer chuck relative said cylindrical sidewalls of said housing.
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9. A plasma reactor according to claim 4 wherein said inner radial wall of said cylindrical dielectric ring has a diameter greater than a diameter of said wafer.
Specification