Multi-State RF Generator Control for Fast Plasma Impedance Response
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Solution Overview
Problem
Existing plasma processing systems face challenges in quickly responding to changes in plasma impedance, which can negatively affect processes such as etching, deposition, and cleaning due to the time required for RF supplies to react to changes in power and frequency.
Innovation Solution
A plasma processing system is configured to operate based on multiple states, using a pulsed signal with three or more states to control RF generators, allowing for rapid adjustment of power and frequency levels to stabilize plasma by determining and applying pre-determined power and frequency levels based on plasma impedance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF power supplies continuously adjust frequency and power levels to respond to plasma impedance changes, then plasma stability is improved, but response time increases due to the adjustment process
Solution Approach 1:
The system pre-sets multiple discrete power and frequency states in advance. When plasma impedance changes are detected, the controller can immediately switch to a pre-configured state that matches the new conditions, eliminating the need for continuous adjustment and reducing response time while maintaining plasma stability.
Solution Approach 2:
The system dynamically switches between multiple discrete power and frequency states based on real-time plasma impedance measurements. This dynamic state switching allows the system to adapt to changing plasma conditions rapidly, improving both response time and plasma stability by selecting from pre-optimized states rather than continuously adjusting parameters.
2Loss of time
If discrete power and frequency states are used instead of continuous adjustment, then response time to impedance changes is reduced, but manufacturing precision may be affected
Solution Approach 1:
The system changes power and frequency parameters by switching between multiple discrete pre-defined states rather than continuous adjustment. Each state represents a specific combination of power and frequency values that has been optimized for particular plasma impedance conditions. This approach reduces response time while maintaining manufacturing precision by selecting from pre-optimized parameter sets.
Data Source
AI summary
Systems and methods for adjusting power and frequency based on three or more states are described. One of the methods includes receiving a pulsed signal having multiple states. The pulsed signal is received by multiple radio frequency (RF) generators. When the pulsed signal having a first state is received, an RF signal having a pre-set power level is generated by a first RF generator and an RF signal having a pre-set power level is generated by a second RF generator. Moreover, when the pulsed signal having a second state is received, RF signals having pre-set power levels are generated by the first and second RF generators. Furthermore, when the pulsed signal having a third state is received, RF signals having pre-set power levels are generated by the first and second RF generators.