Plasma Radical Sensing Feedback Control for Stable Wafer Processing
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Solution Overview
Problem
Current plasma processing systems for semiconductor manufacturing lack in-situ measurement of radical concentration, relying on estimates or iterative corrections, leading to unstable radical yields and increased costs due to trial-and-error methods, which disrupt manufacturing and result in unusable wafers.
Innovation Solution
A feedback control system using radical sensing, comprising a process gas supply, plasma source, process chamber, gas analyzer, and controller, which continuously adjusts operational parameters based on real-time data from a mass spectrometer to maintain targeted radical concentrations, ensuring stable plasma processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If iterative correction processes are used to achieve desired radical concentration, then the target radical concentration can be achieved, but the process becomes laborious, expensive, and interruptive to manufacturing
Solution Approach 1:
The patent implements a feedback control system using a mass spectrometer to continuously monitor radical concentration in the plasma flow. The controller receives real-time signals from the mass spectrometer and adjusts plasma source parameters (power, gas flow rates) to maintain the desired radical concentration, eliminating the need for laborious iterative corrections and off-line metrology while maintaining manufacturing precision and throughput
2Reliability
If radical concentration is not measured in-situ, then system complexity is reduced, but the radical yield drifts over time due to component aging and operational changes
Solution Approach 1:
The system incorporates a mass spectrometer connected to the plasma source output that continuously measures radical concentration in real-time. The controller uses this feedback signal to dynamically adjust plasma source parameters, compensating for drift caused by component aging, cold start events, and surface condition changes, thereby maintaining reliable radical concentration stability
Solution Approach 2:
The patent replaces mechanical/physical monitoring methods with a mass spectrometer-based detection system that uses mass-to-charge ratio analysis to identify and quantify radical species. This substitution enables precise, non-intrusive, real-time measurement of radical concentration without significant mechanical complexity
3Manufacturing precision
If trial-and-error correction methods are employed, then the desired radical concentration can be achieved, but manufacturing costs increase and wafers may become unusable
Solution Approach 1:
The real-time feedback control system continuously monitors radical concentration and adjusts plasma source parameters before processing each wafer, ensuring consistent radical yield from the first wafer rather than requiring trial-and-error corrections across multiple wafers. This eliminates wafer scrap caused by suboptimal radical concentration while maintaining manufacturing precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system enables real-time, in-situ measurement and control of radical concentrations, stabilizing plasma processing, reducing waste, and optimizing manufacturing efficiency by continuously adjusting parameters such as gas flow, power, and pressure to achieve consistent radical yields.
Implementation Method 1
at least one gas analyzer in communication with and configured to sample at least one of the at least one process gas, at least one radical flow
Implementation Method 2
at least one plasma source configured to receive the at least one process gas and generate at least one radical flow
Data Source
AI summary
An apparatus for feedback control in plasma processing systems using radical sensing, and a method for feedback control in plasma processing systems using radical sensing, the apparatus comprising at least one process gas supply system configured to output at least one process gas, at least one plasma source configured to receive the at least one process gas and generate at least one radical flow, at least one process chamber in communication with the at least one plasma source, wherein the process chamber receives the at least one radical flow and directs at least a portion of the at least one radical flow to one or more devices, the process chamber configured to output at least one process chamber output, at least one gas analyzer in communication with and configured to sample at least one of the at least one process gas, at least one radical flow, at least one radical flow within the at least one process chamber, and the at least one process chamber output, and at least one controller in communication with at least one of the process gas supply system, at least one plasma source, and at least one process chamber, the controller configured to generate at least one control signal based on data from the at least one gas analyzer and selectively control at least one of the process gas supply system, at least one plasma source, and at least one process chamber.