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US 4,585,516 AGranted
Variable duty cycle, multiple frequency, plasma reactor
AssigneeTegal Corporation
InventorsGlenn R. Corn, Andreas G. Hegedus
Life of this patent
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Abstract
A plasma reactor and a process for operating a plasma reactor are disclosed. The reactor comprises parallel plates in which one plate is connected to a source of high frequency signal and a second plate is connected to a source of low frequency signal. Control apparatus modulates one or both signals. In the process, the duty cycles of the modulating signals is controlled so that the signals overlap during at least a portion of their cycles.
Claims7
Plasma reactor apparatus comprising:
- first, second and third electrodes defining an enclosed volume for receiving an article to be treated;
- a source of high frequency signal;
- a source of low frequency signal;
- and
- means for selectively connecting said source of high frequency signal to one electrode and said source of low frequency signal to another electrode;
- said means comprising control means for modulating the amplitude of said signals so that at least one of said signals has a duty cycle of less than one hundred percent.
3 more elements
A process for treating semiconductor wafers in a plasma reactor comprising the steps of:
- applying a high frequency signal to a plasma reactor chamber;
- applying a low frequency signal to said plasma reactor chamber;
- supplying a reactant gas to said chamber;
- and
- modulating at least one of said signals so that the duty cycle of the signal is less than one hundred percent.
2 more elements
Dependencies are inferred from the claim text.