Multi-Zone Bias Control for Uniform Plasma Sheath in Etching
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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 substrate edges and chamber artifacts, leading to non-uniform processing results.
Innovation Solution
A system with multiple bias supplies and electrodes that apply an asymmetric periodic voltage waveform to control plasma sheaths, allowing for dynamic and flexible adjustment of the plasma sheath uniformity by varying voltage levels and duty cycles across different zones within the plasma processing chamber.
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 are reduced
Solution Approach 1:
The patent applies parameter changes by using multiple independent bias supplies to dynamically adjust voltage parameters across different zones of the substrate holder. Instead of physically modifying the chamber geometry, the system changes electrical parameters (voltage magnitude and duty cycle) to control plasma sheath characteristics, achieving uniformity control through software-configurable parameters rather than fixed physical structures.
Solution Approach 2:
The invention implements dynamics by enabling real-time, independent control of bias voltage applied to different zones of the substrate holder. The system transitions from static physical geometries to dynamic electrical control, where bias supplies can be adjusted during operation to adapt to varying process requirements and achieve uniform plasma sheath distribution across the substrate surface.
2Device complexity
If static physical geometries are used to control plasma sheath, then device complexity is reduced, but adaptability and flexibility are worsened
Solution Approach 1:
The system maintains simple physical structures while achieving high adaptability through parameter changes. Multiple bias supplies allow independent adjustment of voltage parameters for different zones, enabling the same physical hardware to adapt to various substrate sizes, shapes, and processing requirements without physical reconfiguration.
Solution Approach 2:
The invention achieves universality by designing a substrate holder with multiple zones that can be independently biased. This multi-functional capability allows a single device to handle diverse substrate types and processing scenarios, making the system versatile without requiring multiple specialized physical configurations.
3Manufacturing precision
If asymmetric periodic voltage waveform is applied to bias electrodes, then plasma sheath uniformity is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic action by applying asymmetric periodic voltage waveforms to the bias electrodes. The waveforms alternate between different voltage levels and duty cycles in a periodic manner, creating controlled plasma sheath dynamics that improve uniformity. The periodic nature allows energy-efficient cycling between high and low power states while maintaining processing effectiveness.
Solution Approach 2:
The system optimizes energy consumption through parameter changes in the voltage waveforms. By adjusting the duty cycle and voltage amplitude parameters of the asymmetric periodic waveforms, the system achieves uniform plasma sheath distribution while managing power consumption. Different zones can use different parameter settings to balance uniformity requirements with energy efficiency.
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 achieves uniform plasma sheath distribution and improved substrate processing by mitigating non-uniformities, enabling more precise control over the plasma processing environment.
Implementation Method 1
at least two bias electrodes arranged within the plasma processing chamber to control plasma sheaths proximate to the bias electrodes
Implementation Method 2
a controller to control the at least one bias supply to apply an asymmetric periodic voltage waveform to each of the at least two bias electrodes to control the 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.