Plasma Processing Bias Circuits for Substrate and Edge Ring Uniformity
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in maintaining uniform voltage waveforms between the substrate and the edge ring, leading to inefficiencies in plasma processing due to the higher capacitance of the substrate compared to the edge ring.
Innovation Solution
The plasma processing apparatus incorporates a first bias power source and a second bias power source connected to separate electrodes, with a first circuit and a second circuit having different impedances at a common bias frequency. This configuration reduces the difference in voltage waveforms between the substrate and the edge ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bias power source is used for both substrate and edge ring, then device complexity is reduced, but voltage waveform uniformity deteriorates due to different capacitance values
Solution Approach 1:
The patent divides the bias power supply system into two separate bias power sources: a first bias power source connected to the substrate electrode and a second bias power source connected to the edge ring electrode. This segmentation allows independent control and optimization of voltage waveforms for each component, resolving the contradiction by accepting increased device complexity to achieve voltage waveform uniformity.
Solution Approach 2:
The patent applies different impedance values to different parts of the system: the first circuit has a first impedance value for the substrate path, and the second circuit has a second impedance value for the edge ring path. This local differentiation of electrical characteristics allows each component to receive appropriately tailored voltage waveforms, achieving uniformity despite different capacitance values.
2Stability of the object's composition
If different impedance circuits are used for substrate and edge ring, then voltage waveform uniformity is improved, but device complexity increases
Solution Approach 1:
The patent introduces impedance circuits as intermediary elements between the bias power sources and the electrodes. The first circuit with first impedance and the second circuit with second impedance act as mediators that shape and regulate the voltage waveforms, enabling uniform voltage application across components with different capacitance values while maintaining a structured and manageable circuit architecture.
3Productivity
If bias power is supplied to lower electrode only, then ion extraction is achieved, but voltage distribution uniformity deteriorates
Solution Approach 1:
The patent segments the electrode system into functionally distinct components: the lower electrode (first electrode) for ion extraction and the edge ring electrode (second electrode) for voltage distribution control. By supplying bias power to both segmented electrodes through separate bias power sources and impedance circuits, the system achieves both effective ion extraction and uniform voltage distribution simultaneously.
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 achieves a more uniform voltage distribution between the substrate and the edge ring, enhancing the efficiency of plasma processing by reducing the impedance difference between the circuits.
Implementation Method 1
The first bias power source is configured to generate a first electrical bias and electrically connected to the first electrode
Implementation Method 2
The second bias power source is configured to generate a second electrical bias and electrically connected to the second electrode
Implementation Method 3
The second circuit has impedance higher than impedance of the first circuit at a common bias frequency of the first electrical bias and the second electrical bias
Data Source
AI summary
A disclosed plasma processing apparatus includes a substrate support. The substrate support has a first region configured to support a substrate and a second region configured to support an edge ring. The first electrode is provided in the first region. The second electrode is provided in the second region. The first bias power source is connected to the first electrode via the first circuit. The second bias power source is connected to the second electrode via the second circuit. The second circuit has impedance higher than impedance of the first circuit at a common bias frequency of a first electrical bias generated by the first bias power source and a second electrical bias generated by the second bias power source.