RF Impedance Matching for Plasma Ignition Stability
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Solution Overview
Problem
In semiconductor manufacturing, achieving successful ignition of pulsed plasma requires high pulse overshoot power and longer pulse times, but existing methods often fail to ensure consistent plasma ignition due to impedance mismatch issues.
Innovation Solution
A method for radio frequency (RF) impedance matching that involves frequency scanning across multiple pulse periods, where the start value of each pulse phase's frequency scanning parameter is consistent with the end value of the previous phase, allowing the frequency scanning parameter to stabilize and match a target value, reducing the need for excessive power and avoiding instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher pulse overshoot power and longer pulse overshoot time are loaded, then plasma ignition success rate is improved, but power consumption increases and system complexity increases
Solution Approach 1:
The patent implements dynamic impedance matching by continuously adjusting the matching impedance parameters during the pulse overshoot period based on real-time plasma impedance changes. This dynamic adjustment allows the system to achieve plasma ignition with lower peak power by adapting to the evolving plasma state, rather than using fixed high power settings throughout the pulse duration.
Solution Approach 2:
The patent changes the impedance matching parameters (real part and imaginary part) as functions of time during the pulse overshoot period. By optimizing these parameters dynamically, the system achieves better plasma coupling efficiency, reducing the overall power consumption required for successful ignition while maintaining high ignition success rate.
2Reliability
If higher pulse overshoot power and longer pulse overshoot time are loaded, then plasma ignition success rate is improved, but device complexity increases
Solution Approach 1:
The patent employs a feedback mechanism where the impedance matching parameters are continuously adjusted based on real-time monitoring of plasma impedance during the pulse overshoot period. This feedback control enables the system to automatically optimize the matching conditions, achieving high ignition success rates without requiring complex manual intervention or overly sophisticated hardware configurations.
Solution Approach 2:
The system uses dynamic impedance matching where the matching network parameters are adjusted in real-time during the pulse overshoot period. This dynamic adaptation simplifies the overall system design compared to static high-power systems, as the system can achieve ignition success through intelligent parameter adjustment rather than relying on excessive power capacity built into the hardware.
3Measurement precision
If frequency scanning is performed across multiple pulse periods with continuous parameter adjustment, then impedance matching precision is improved, but processing time increases
Solution Approach 1:
The patent performs frequency scanning and impedance matching during the pulse overshoot period, which occurs before the main plasma processing begins. By completing the impedance matching process in advance during the overshoot period, the system ensures precise matching for the subsequent steady-state plasma operation without adding extra processing time to the main workflow.
Solution Approach 2:
The patent implements periodic frequency scanning across multiple pulse periods, where the impedance matching parameters are adjusted in a systematic periodic manner. This approach allows the system to converge to the optimal matching point efficiently, achieving high precision while minimizing the time required compared to continuous or random search methods.
Data Source
AI summary
A method for radio frequency impedance matching includes performing frequency scanning matching using first n pulse phases of first m pulse periods as a frequency scanning stage, and from an (m+1)-th pulse period to an M-th pulse period, maintaining a frequency scanning parameter of a pulse phase corresponding to each frequency scanning stage of each pulse period. The radio frequency includes M pulse periods, each pulse period includes N pulse phases, M and N are integers greater than 1, m and n are integers greater than 0, m<M, n≤N, and i=1, 2, . . . , m. A start value of the frequency scanning parameter of each frequency scanning stage of an (i+1)-th pulse period is consistent with an end value of the frequency scanning parameter of each frequency scanning stage of the i-th pulse period. Accordingly, an end value of the frequency scanning parameter of each frequency scanning stage of an m-th pulse period matches a preset target value of the frequency scanning parameter.