Multi-Electrode Bias Control for Uniform Plasma Sheaths
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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 of the substrate, due to discontinuities caused by substrate edges and chamber artifacts, leading to non-uniform ion trajectories and processing issues.
Innovation Solution
A system with multiple bias supplies and electrodes is used to apply an asymmetric periodic voltage waveform to control plasma sheaths. This system includes a plasma processing chamber with bias electrodes and a chuck for substrate support, allowing for independent control of bias supplies to create non-uniform biasing across the electrode, thereby achieving uniform surface potential on the substrate.
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 in certain regions, but the system becomes static and inflexible, unable to dynamically adjust to different processing requirements
Solution Approach 1:
The patent applies dynamics by using multiple independently controllable bias supplies that can dynamically adjust voltage waveforms in real-time during plasma processing. Unlike static physical modifications, the bias supplies can change operating parameters on-the-fly to adapt to different processing requirements and maintain sheath uniformity under varying conditions.
Solution Approach 2:
The invention changes physical parameters by applying different voltage waveforms (frequency, amplitude, phase) to different bias electrodes. This allows dynamic control of plasma sheath characteristics without physical modifications, enabling the system to adapt to various processing scenarios by adjusting electrical parameters rather than mechanical geometry.
2Manufacturing precision
If multiple bias supplies with asymmetric periodic voltage waveforms are applied to different zones, then plasma sheath uniformity and processing precision are improved, but the device complexity increases
Solution Approach 1:
The patent segments the substrate processing surface into multiple zones, each served by an independent bias supply. This segmentation allows localized control of plasma sheath in different regions, achieving high processing uniformity across the substrate while managing complexity through modular, independently controllable units rather than a monolithic complex system.
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
The solution effectively addresses the non-uniformities in plasma processing by dynamically controlling the plasma sheath uniformity and intensity spatially and temporally, leading to improved substrate processing uniformity and efficiency.
Implementation Method 1
at least two bias electrodes arranged within the plasma processing chamber to control plasma sheaths proximate to the bias electrodes
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.