Plasma Source Stability Monitoring via Light Intensity
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Solution Overview
Problem
Plasma processing tools face challenges in detecting and addressing plasma discharge stability and chamber-to-chamber variations due to hardware component variations and non-optimized process conditions, leading to non-repeatable plasma characteristics and increased manufacturing complexity.
Innovation Solution
Implementing an image capture technique using an image sensor to determine plasma light intensity and adjust operating parameters for plasma sources and process chambers, allowing for automatic or manual spectra analysis to improve plasma discharge stability and chamber matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-zone optical emission spectrometer is used to collect fluorescence for plasma detection, then plasma density variation can be detected, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts only the necessary detection function from complex spectrometers by using simple photodetectors positioned at specific locations around the plasma source. This extraction approach captures sufficient plasma density information without requiring the full complexity of multi-zone optical emission spectrometers, thereby reducing device complexity while maintaining adequate measurement precision for process control.
Solution Approach 2:
The patent replaces expensive, complex optical emission spectrometers with inexpensive photodetectors and simple optical components. These simpler components achieve the essential function of detecting plasma density variations at key locations, providing a cost-effective solution that eliminates the need for sophisticated instrumentation while still enabling effective plasma monitoring and chamber-to-chamber matching.
2Reliability
If viewport and optical emission spectrometer are added for plasma observation, then plasma stability can be monitored, but manufacturing cost and overhead increase
Solution Approach 1:
The patent extracts the essential monitoring function from complex optical systems by using simple photodetectors that measure light intensity from plasma emissions. By positioning these detectors at strategic locations around the plasma source, the system captures sufficient information about plasma stability and density without requiring viewports or sophisticated spectrometers, thereby maintaining reliability while reducing manufacturing overhead.
Solution Approach 2:
The patent replaces mechanical/optical systems (viewports, spectrometers) with a simpler electrical detection system using photodetectors. This substitution eliminates the need for physical viewports and complex optical pathways, using instead electrical signals from photodetectors to monitor plasma characteristics,ไป่ reducing manufacturing complexity and overhead while maintaining plasma stability monitoring capability.
3Reliability
If chamber-to-chamber hardware variations are reduced through tighter tolerances, then plasma stability improves, but manufacturing cost increases
Solution Approach 1:
The patent implements feedback-based chamber-to-chamber matching by measuring plasma characteristics (light intensity, density) from each process chamber and using this information to adjust operating parameters. This feedback approach compensates for hardware variations without requiring tight manufacturing tolerances, allowing standard manufacturing practices to be maintained while achieving consistent plasma performance across chambers through software-controlled parameter adjustment.
Solution Approach 2:
The patent addresses hardware variations by changing operating parameters (power, gas flow, pressure) based on measured plasma characteristics from each chamber. Instead of requiring identical hardware, the system adapts parameters for each chamber to achieve uniform plasma performance, thereby maintaining ease of manufacture with standard tolerances while improving plasma discharge repeatability through parameter optimization.
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 approach provides a simple, low-cost solution for detecting plasma instability and chamber-to-chamber variations, enabling improved plasma source stability and process control, reducing chamber-to-chamber differences and enhancing manufacturing efficiency.
Implementation Method 1
capturing images with the image sensor during the performing where the images are associated with the plasma source, and adjusting one or more operating parameters based upon light intensity distributions determined from the captured images
Data Source
AI summary
Methods are disclosed to detect plasma light emissions during plasma processing, to analyze light intensity data associated with the plasma source, and to adjust operating parameters for the plasma source and/or the process chamber based upon light intensity distributions associated with the plasma processing. The light intensity distributions for the plasma sources and related analysis can be conducted across multiple processing tools. For some embodiments, plasma discharge stability and/or chamber-to-chamber matching information is determined based upon light intensity data, and the operation of the processing tools are adjusted or controlled based upon stability and/or matching determinations. The disclosed embodiments thereby provide simple, low-cost solutions to assess and improve plasma sources and discharge stability for plasma processing tools such as plasma etch and deposition tools.