Sidewall smoothing in high aspect ratio/deep etching using a discrete gas switching method
First Claim
1. An apparatus for improved gas switching, said apparatus comprising:
- a plasma chamber;
at least one plasma source for producing a plasma within said plasma chamber;
a substrate holder positioned within said plasma chamber;
an etchant gas supply having an associated gas inlet for providing an etchant gas to said plasma chamber and an associated gas bypass for exhausting said etchant gas;
a deposition gas supply having an associated gas inlet for providing a deposition gas to said plasma chamber and an associated gas bypass for exhausting said deposition gas; and
a gas control switch for controlling at least one of said etchant gas supply and said deposition gas supply such that said gas inlet and said gas bypass of said at least one gas supply are configured such that gas flows bypass the chamber when said gas inlet is closed.
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Accused Products
Abstract
An improved method for introducing gases into an alternating plasma etching/deposition chamber is provided by the present invention. To minimize the introduction of pressure pulses into the alternating etching/deposition chamber when the deposition and etchant gas supplies are switched on and off, a mass flow controller is used to provide a relatively constant flow of gas. A gas bypass or a gas exhaust is provided such that when a gas inlet to the alternating etching/deposition chamber is closed an alternative path is provided for the flow of gas from the mass flow controller. The provision of a bypass or exhaust maintains the pressure of the gas received from the mass flow controller at a substantially constant level. The elimination or minimization of a pressure pulse of the gas helps increase the smoothness of the walls of high aspect ratio features etched in a silicon substrate in the alternating etching/deposition chamber.
41 Citations
20 Claims
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1. An apparatus for improved gas switching, said apparatus comprising:
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a plasma chamber;
at least one plasma source for producing a plasma within said plasma chamber;
a substrate holder positioned within said plasma chamber;
an etchant gas supply having an associated gas inlet for providing an etchant gas to said plasma chamber and an associated gas bypass for exhausting said etchant gas;
a deposition gas supply having an associated gas inlet for providing a deposition gas to said plasma chamber and an associated gas bypass for exhausting said deposition gas; and
a gas control switch for controlling at least one of said etchant gas supply and said deposition gas supply such that said gas inlet and said gas bypass of said at least one gas supply are configured such that gas flows bypass the chamber when said gas inlet is closed. - View Dependent Claims (2)
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3. A gas supply system for providing gas to an alternating deposition/etching chamber used to manufacture semiconductors, said gas supply system comprising:
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a mass flow controller for providing a flow of gas;
a gas inlet for introducing gas from said mass flow controller into said deposition/etching chamber; and
a gas bypass for exhausting gas from said mass flow controller when said gas inlet is closed. - View Dependent Claims (4, 5, 6)
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7. A method of controlling a flow of gas from a mass flow controller to a semiconductor manufacturing chamber to maximize a smoothness of sidewalls of etched trenches in a silicon substrate, said method comprising:
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providing a specified flow of gas from the mass flow controller;
providing the flow of gas from the mass flow controller to the chamber during a gas on state; and
diverting the flow of gas from the mass flow controller during a gas off state. - View Dependent Claims (8)
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9. A method of anisotropic plasma etching of silicon in a chamber to provide laterally defined recess structures therein with smooth sidewalls, the method comprising:
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providing to said chamber pulses of a reactive etchant gas for etching silicon alternated by pulses of a reactive polymerizing gas for depositing a polymer layer;
plasma etching in at least one etching step a surface of the silicon by contact with said reactive etching gas to remove material from the surface of the silicon and provide exposed surfaces;
polymerizing in at least one polymerizing step at least one polymer onto the surface of the silicon by contact with said reactive polymerizing gas during which the surfaces that were exposed in said preceding etching step are covered by a polymer layer thereby forming a temporary etching stop; and
alternatingly repeating the etching step and the polymerizing step. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification