Method and apparatus for etch endpoint detection
First Claim
1. A method for monitoring a plasma optical emission, comprising:
- collecting optical emission data from a plasma through an aperture defined by moveable members, wherein the moveable members are capable of varying a configuration of the aperture, wherein the moveable members are confinement rings within a plasma etching chamber;
holding the moveable members at a particular time, wherein the holding causes the aperture to maintain a fixed configuration; and
detecting a specific perturbation in the plasma optical emission while holding the moveable members.
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Abstract
Broadly speaking, an invention is provided for monitoring a plasma optical emission. More specifically, the present invention provides a method for monitoring the plasma optical emission through a variable aperture to detect an endpoint of a plasma etching process without interferences that could lead to false endpoint calls. The method includes collecting optical emission data from a plasma through an aperture defined by moveable members. The moveable members are capable of varying a configuration of the aperture. The method also includes holding the moveable members at a particular time to cause the aperture to maintain a fixed configuration. The method further includes detecting a specific perturbation in the plasma optical emission while holding the moveable members.
11 Citations
19 Claims
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1. A method for monitoring a plasma optical emission, comprising:
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collecting optical emission data from a plasma through an aperture defined by moveable members, wherein the moveable members are capable of varying a configuration of the aperture, wherein the moveable members are confinement rings within a plasma etching chamber; holding the moveable members at a particular time, wherein the holding causes the aperture to maintain a fixed configuration; and detecting a specific perturbation in the plasma optical emission while holding the moveable members. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for detecting an endpoint of a plasma etching process, comprising:
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performing a plasma etching process within a chamber having moveable confinement rings; reaching a pre-designated time prior to an anticipated endpoint time of the plasma etching process; holding the moveable confinement rings in a fixed position upon reaching the pre-designated time prior to the anticipated endpoint time of the plasma etching process; monitoring a plasma optical emission from a window through gaps between the moveable confinement rings, wherein the monitoring is performed while the moveable confinement rings are being held in the fixed position relative to the window; and detecting a perturbation in the plasma optical emission, the perturbation being indicative of an endpoint of the plasma etching process. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A chamber for providing a plasma to perform an etching process, comprising:
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a chuck for holding a substrate within the chamber; a window in the chamber for monitoring the plasma when performing the etching process; a plurality of confinement rings surrounding the chuck, the window providing a view of the plasma through one or more spaces defined by at least one of the plurality of confinement rings; and a confinement ring movement controller capable of setting programmable periods of time for moving the plurality of confinement rings, the confinement ring movement controller being capable of holding the plurality of confinement rings during a programmable period of time when monitoring for an endpoint condition through the window. - View Dependent Claims (16, 17, 18, 19)
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Specification