Micromachined silicon electrostatic chuck
First Claim
1. An electrostatic chuck, comprising:
- a metallic base plate;
a silicon plate attached to said metallic base plate; and
a plurality of non-conductive support islands formed on the surface of said silicon plate opposite said metallic base plate for preventing electrical contact between the surface of said patterned silicon plate and a silicon wafer undergoing microelectronic processing.
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Accused Products
Abstract
An electrostatic chuck is faced with a patterned silicon plate 11, createdy micromachining a silicon wafer, which is attached to a metallic base plate 13. Direct electrical contact between the chuck face 15 (patterned silicon plate'"'"'s surface) and the silicon wafer 17 it is intended to hold is prevented by a pattern of flat-topped silicon dioxide islands 19 that protrude less than 5 micrometers from the otherwise flat surface of the chuck face 15. The islands 19 may be formed in any shape. Islands may be about 10 micrometers in diameter or width and spaced about 100 micrometers apart. One or more concentric rings formed around the periphery of the area between the chuck face 15 and wafer 17 contain a low-pressure helium thermal-contact gas used to assist heat removal during plasma etching of a silicon wafer held by the chuck. The islands 19 are tall enough and close enough together to prevent silicon-to-silicon electrical contact in the space between the islands, and the islands occupy only a small fraction of the total area of the chuck face 15, typically 0.5 to 5 percent. The pattern of the islands 19, together with at least one hole 12 bored through the silicon veneer into the base plate, will provide sufficient gas-flow space to allow the distribution of the helium thermal-contact gas.
467 Citations
21 Claims
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1. An electrostatic chuck, comprising:
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a metallic base plate; a silicon plate attached to said metallic base plate; and a plurality of non-conductive support islands formed on the surface of said silicon plate opposite said metallic base plate for preventing electrical contact between the surface of said patterned silicon plate and a silicon wafer undergoing microelectronic processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An electrostatic chuck comprising:
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a metallic base plate; a patterned silicon plate attached to said metallic plate, said patterned silicon plate having an exposed surface opposite attachment to said metallic base plate; a plurality of densely spaced non-conductive contact means formed on said exposed surface of said patterned silicon plate and protruding a small distance from said exposed surface wherein said electrical contact means prevent direct electrical contact between said patterned silicon plate and a silicon wafer; wherein said chuck has at least one hole bored through said patterned silicon plate and said metallic base plate to provide sufficient gas-flow space to allow the distribution of helium thermal-contact gas, and said plurality of non-conductive contact means comprise a plurality of support island wherein said plurality of support islands are comprised of a pattern of flat-topped silicon dioxide islands that protrude from said patterned silicon plate exposed surface. - View Dependent Claims (17, 18, 19, 20)
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21. An electrostatic chuck comprising:
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an aluminum base plate; a patterned silicon plate having a silicon surface attached in electrical contact to said aluminum base plate; and a plurality of support island wherein said plurality of support islands are comprised of a pattern of flat-topped silicon dioxide islands that protrude less than 5 micrometers away from said silicon surface of said patterned silicon plate and said islands are about 10 micrometers wide and spaced about 100 micrometers apart; wherein said chuck has at least one hole bored through said patterned silicon plate and said aluminum base plate to provide sufficient gas-flow space to allow the distribution of the helium thermal-contact gas, and wherein direct electrical contact between said patterned silicon plate surface and a silicon wafer to be supported is prevented.
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Specification