Multi-Frequency Plasma RF Control for Stable Pulsed Processing
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Solution Overview
Problem
Existing plasma processing systems experience RF power instability and plasma perturbations due to unsynchronized RF signal pulsing, which affects process results and device yield, particularly in high-density, high-performance device fabrication.
Innovation Solution
Proactively synchronize and set RF power levels of higher frequency RF signals in response to the pulsing state of the base RF signal, minimizing RF power perturbations by using a master RF power supply or external control circuit to coordinate pulsing among multiple RF power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple RF signals are pulsed unsynchronized to improve plasma processing flexibility, then processing adaptability is improved, but RF power instability and plasma perturbations occur
Solution Approach 1:
The patent applies preliminary action by proactively synchronizing the pulsing of multiple RF signals before plasma perturbations can occur. The master RF power supply coordinates the pulsing timing of slave RF power supplies in advance, ensuring that all RF signals transition together. This prevents the RF power instability and plasma perturbations that would otherwise result from unsynchronized pulsing, while maintaining the processing flexibility needed for high-density device fabrication.
2Manufacturing precision
If RF signals are pulsed to improve certain processing results, then manufacturing precision is improved, but RF power perturbations occur during transitions
Solution Approach 1:
The patent merges the pulsing control of multiple RF signals by using a master RF power supply to coordinate all slave RF power supplies. This combining approach ensures that all RF signals pulse simultaneously in unison, maintaining manufacturing precision for improved processing results while eliminating RF power perturbations that would occur during unsynchronized transitions. The synchronized pulsing maintains consistent total RF power delivery to the plasma.
Data Source
AI summary
Methods and apparatus for processing a substrate in a multi-frequency plasma processing chamber are disclosed. The base RF signal pulses between a high power level and a low power level. Each of the non-base RF generators, responsive to a control signal, proactively switches between a first predefined power level and a second predefined power level as the base RF signal pulses. Alternatively or additionally, each of the non-base RF generators, responsive to a control signal, proactively switches between a first predefined RF frequency and a second predefined RF frequency as the base RF signal pulses. Techniques are disclosed for ascertaining in advance of production time the first and second predefined power levels and/or the first and second predefined RF frequencies for the non-base RF signals.