Endpoint detection methods in plasma etch processes and apparatus therefor
AssigneeLam Research Corporation
InventorFangli Hao
Life of this patent
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Abstract
Methods for determining an endpoint for a plasma etching process. The plasma etching process is employed to etch a substrate in a plasma processing chamber. The method includes detecting, using a mass analyzer, a density of a predefined compound in the plasma processing chamber. The method further includes outputting from the mass analyzer a variable signal responsive to the detecting. There is also included producing, responsive to the variable signal, a control signal. The control signal is outputted when a predefined density criteria is detected in the variable signal. Additionally, there is included initiating an etch termination procedure, responsive to the control signal, thereby ending the plasma etching process at an end of the etch termination procedure.
Claims16
A method for determining an endpoint for a plasma etching process, said plasma etching process being employed to etch a substrate in a plasma processing chamber, the method comprising:
- detecting, using a mass analyzer, a density of a predefined compound in said plasma processing chamber;
- outputting from said mass analyzer a variable signal responsive to said detecting;
- producing, responsive to said variable signal, a control signal, said control signal being outputted when a predefined density criteria is detected in said variable signal;
- and
- initiating an etch termination procedure, responsive to said control signal, thereby ending said plasma etching process at an end of said etch termination procedure.
A method for determining an endpoint for a plasma etching process, said plasma etching process being employed to etch a substrate in a plasma processing chamber, the method comprising:
- directing a beam of light through a region of said plasma processing chamber during said plasma etching process, said region containing byproducts of said plasma etching process, compounds of said byproducts having different light absorbing characteristics;
- detecting an intensity of said beam of light after said beam of light passes through said region;
- generating from said detecting a variable signal representative of a density of a predefined compound of said compounds in said byproducts;
- producing, responsive to said variable signal, a control signal, said control signal being outputted when a predefined density criteria is detected in said variable signal;
- and
- initiating an etch termination procedure, responsive to said control signal, thereby ending said plasma etching process at an end of said etch termination procedure.
A method for determining an endpoint for a plasma etching process, said plasma etching process being employed to etch a substrate in a plasma processing chamber, comprising:
- employing a first endpoint sensor to determine a first endpoint of said plasma etching process;
- employing a second endpoint sensor different from said first endpoint sensor to determine a second endpoint of said plasma etching process;
- ascertaining whether said first endpoint and said second endpoint are ascertained within a predefined time period;
- and
- initiating an etch termination procedure if said first endpoint and said second endpoint are ascertained within said predefined time period.
Dependencies are inferred from the claim text.