Frequency enhanced impedance dependent power control for multi-frequency RF pulsing

摘要

Methods for processing a substrate in a plasma processing, chamber employing a plurality of RF power supplies. The method includes pulsing at a first pulsing frequency a first RF power supply to deliver a first RF signal between a high power state and a low power state. The method further includes switching the RF frequency of a second RF signal output by a second RF power supply between a first predefined RF frequency and a second RF frequency responsive to values of a measurable chamber parameter. The first RF frequency and the second RF frequencies and the thresholds for switching were learned in advance during a learning phase while the first RF signal pulses between the high power state and low power state at a second RF frequency lower than the first RF frequency and while the second RF power supply operates in different modes.

主权项

1. A method for processing a substrate in a plasma processing system having at least one plasma processing chamber, said plasma processing chamber employing a plurality of RF power supplies for sustaining a plasma within said plasma processing chamber during said processing, comprising:
pulsing a first RF power supply of said plurality of RF power supplies to deliver a first RF signal between a high power state and a low power state, wherein said pulsing is performed at a first pulsing frequency; and operating a second RF power supply of said plurality of RF power supplies in a fixed frequency mode wherein said second RF power supply is not permitted to self-tune a frequency of a second RF signal output by said second RF power supply and wherein said second RF signal operates with at least two fixed alternate RF frequency values: a first RF frequency value and a second RF frequency value, wherein said first RF frequency value and said second RF frequency value are learned earlier during a learning phase when said second RF power supply operates in a frequency self-tuning mode to self-tune an RF frequency of said second RF signal in response to said first RF signal pulsing between said high power state and said low power state at a second pulsing frequency lower than said first pulsing frequency.