Plasma Sheath Bias Control for Uniform Substrate Edge Processing
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Solution Overview
Problem
Plasma processing chambers face challenges in controlling the uniformity of the plasma sheath above the substrate, particularly around the edge, due to discontinuities caused by the substrate edge and chamber artifacts, leading to non-uniform ion trajectories and processing inefficiencies.
Innovation Solution
A system with multiple bias supplies and electrodes that apply asymmetric periodic voltage waveforms to control plasma sheaths, allowing for dynamic and flexible adjustment of biasing across different zones within the plasma processing chamber to achieve uniform surface potential and mitigate non-uniformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical changes in substrate holder or chamber shape are used to control plasma sheath uniformity, then sheath uniformity can be improved, but device complexity and flexibility deteriorate
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting electrical parameters (voltage, frequency, phase) of bias supplies rather than modifying physical geometry. Multiple bias electrodes receive independently controllable voltage waveforms, allowing real-time optimization of plasma sheath uniformity through electrical parameter tuning instead of fixed physical modifications.
Solution Approach 2:
The invention implements dynamics by enabling real-time, dynamic control of bias voltages applied to different zones of the substrate holder. The system can adaptively adjust voltage magnitudes and phases during operation to compensate for edge effects and maintain uniform plasma sheath, replacing static physical modifications with dynamic electrical control.
2Manufacturing precision
If static physical modifications are made to substrate holder geometry, then plasma sheath uniformity can be improved, but adaptability deteriorates
Solution Approach 1:
The system enables adaptability through independent control of multiple bias supplies, allowing different voltage parameters to be applied to different radial zones. This electrical parameter flexibility allows the same physical hardware to adapt to various process requirements and substrate types without physical reconfiguration.
Solution Approach 2:
The substrate holder is segmented into multiple radial zones with independent bias control. This segmentation allows each zone to be independently optimized for plasma sheath uniformity while maintaining overall system adaptability. The segmented electrical control regions can be individually adjusted for different process conditions.
3Manufacturing precision
If asymmetric periodic voltage waveforms are applied to bias electrodes, then plasma sheath uniformity and processing precision are improved, but device complexity increases
Solution Approach 1:
The patent employs asymmetric periodic voltage waveforms with controllable amplitude, frequency, and phase parameters to optimize plasma sheath characteristics. This parameter-based control achieves superior processing precision by independently tuning electrical characteristics for each bias electrode, replacing complex physical modifications with programmable electrical control.
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 ensures a uniform plasma sheath and improved substrate processing by dynamically controlling ion energies and processing rates, enhancing the precision and effectiveness of plasma processing.
Implementation Method 1
A plasma processing chamber includes a source to provide a plasma in the processing chamber
Implementation Method 2
at least two bias electrodes arranged within the plasma processing chamber to control plasma sheaths proximate to the bias electrodes
Implementation Method 3
adjusting one or more characteristics of the asymmetric periodic voltage waveforms to alter corresponding portions of a plasma sheath
Data Source
AI summary
Systems and methods for plasma processing are disclosed. An exemplary system may include a plasma processing chamber including a source to produce a plasma in the processing chamber and at least two bias electrodes arranged within the plasma processing chamber to control plasma sheaths proximate to the bias electrodes. A chuck is disposed to support a substrate, and a source generator is coupled to the plasma electrode. At least one bias supply is coupled to the at least two bias electrodes, and a controller is included to control the at least one bias supply to control the plasma sheaths proximate to the bias electrodes.