Biasing system for a plasma processing apparatus
First Claim
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1. A method comprising:
- inputting a first process gas into a process chamber;
generating a first plasma from the first process gas;
attracting ions of the first plasma towards a workpiece by biasing a platen positioned in the process chamber on which the workpiece is disposed with a negatively biased DC signal during a first processing time interval;
stopping a flow of the first process gas into the process chamber;
inputting a cleaning gas into the process chamber;
generating a cleaning plasma from the cleaning gas; and
accelerating ions of the cleaning plasma towards interior surfaces of the process chamber housing during a cleaning time interval separate from the first processing time interval, by biasing the platen with a positively biased DC signal.
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Abstract
A plasma processing apparatus includes a process chamber housing defining a process chamber, a platen positioned in the process chamber for supporting a workpiece, a source configured to generate plasma in the process chamber, and a biasing system. The biasing system is configured to bias the platen to attract ions from the plasma towards the workpiece during a first processing time interval and configured to bias the platen to repel ions from the platen towards interior surfaces of the process chamber housing during a cleaning time interval. The cleaning time interval is separate from the first processing time interval and occurring after the first processing time interval.
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Citations
10 Claims
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1. A method comprising:
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inputting a first process gas into a process chamber; generating a first plasma from the first process gas; attracting ions of the first plasma towards a workpiece by biasing a platen positioned in the process chamber on which the workpiece is disposed with a negatively biased DC signal during a first processing time interval; stopping a flow of the first process gas into the process chamber; inputting a cleaning gas into the process chamber; generating a cleaning plasma from the cleaning gas; and accelerating ions of the cleaning plasma towards interior surfaces of the process chamber housing during a cleaning time interval separate from the first processing time interval, by biasing the platen with a positively biased DC signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method comprising:
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inputting a first process gas comprising a p-type dopant into a process chamber; generating a first plasma from the first process gas; attracting ions of the first plasma towards a workpiece by biasing a platen positioned in the process chamber on which the workpiece is disposed with a negatively biased DC signal during a first processing time interval; stopping a flow of the first process gas into the process chamber; inputting a cleaning gas into the process chamber; generating a cleaning plasma from the cleaning gas; accelerating ions of the cleaning plasma towards interior surfaces of the process chamber housing during a cleaning time interval separate from the first processing time interval, by biasing the platen with a positively biased DC signal of a first amplitude; stopping a flow of the cleaning gas into the process chamber; inputting a second process gas comprising a n-type dopant into a process chamber; generating a second plasma from the second process gas; accelerating ions of the second plasma towards interior surfaces of the process chamber housing during a conditioning time interval separate from the first processing time interval and the cleaning time interval, by biasing the platen with a positively biased DC signal of a second amplitude, less than the first amplitude; and attracting ions of the second plasma towards a workpiece by biasing the platen with a negatively biased DC signal during a second processing time interval, separate from the first processing time interval, the cleaning time interval and the conditioning time interval. - View Dependent Claims (9, 10)
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Specification