Dual Baffle Plate Biasing for Plasma Chamber Particle Suppression
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Solution Overview
Problem
The diffusion of charged particles from the processing space into the exhaust space in a plasma processing chamber is not effectively suppressed, leading to inefficiencies in the plasma processing apparatus.
Innovation Solution
The plasma processing apparatus employs a configuration with a first and second baffle plate, where the second baffle plate is electrically connected to a power supply that applies a higher voltage than the first baffle plate, particularly during specific phases of the waveform cycle, to prevent the flow of positive ions and secondary electrons from the processing space into the exhaust space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single baffle plate is used to separate processing space and exhaust space, then the structure is simple, but charged particles diffuse from processing space into exhaust space
Solution Approach 1:
The single baffle plate is segmented into two separate baffle plates (first and second baffle plates) positioned at different locations. This segmentation creates multiple barriers to charged particle diffusion while maintaining structural simplicity. Each baffle plate can be independently controlled, allowing for optimized particle suppression without excessive complexity.
Solution Approach 2:
The first and second baffle plates act as intermediary elements between the processing space and exhaust space. By introducing these intermediate barriers with independent voltage control, the patent effectively mediates the charged particle flow, preventing direct diffusion from processing to exhaust space while maintaining a relatively simple overall structure.
2Object-affected harmful factors
If higher voltage is applied to suppress charged particles, then particle diffusion is reduced, but energy consumption increases
Solution Approach 1:
The power supplies for the first and second baffle plates operate periodically, applying voltages in synchronized cycles. This periodic action allows the system to suppress charged particles only when necessary, reducing continuous energy consumption while maintaining effective particle control during critical phases of the plasma processing cycle.
Solution Approach 2:
The voltage applied to each baffle plate is dynamically adjusted based on real-time conditions. The power supplies can vary voltage levels and timing to match the plasma processing requirements, optimizing particle suppression efficiency while minimizing energy waste during phases when suppression is less critical.
3Object-affected harmful factors
If baffle plates are positioned closer to substrate support, then particle suppression is improved, but the processing space is reduced
Solution Approach 1:
By segmenting the baffle structure into two plates at different positions, the system can place the first baffle plate closer to the substrate support for effective particle suppression, while the second baffle plate is positioned further away to preserve processing space. This segmented approach allows optimized positioning without sacrificing either suppression effectiveness or available processing volume.
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 configuration effectively suppresses the diffusion of charged particles from the processing space into the exhaust space, enhancing the efficiency of the plasma processing by maintaining a controlled environment within the chamber.
Implementation Method 1
a value of a voltage that is applied to the second baffle plate by the second power supply is higher than a value of a voltage that is applied to the first baffle plate by the first power supply
Implementation Method 2
The plasma generator is configured to generate plasma from a gas within the chamber
Data Source
AI summary
A plasma processing apparatus disclosed herein includes a first baffle plate and a second baffle plate. The first baffle plate and the second baffle plate are disposed between a processing space and an exhaust space in a chamber. The second baffle plate is provided downstream of the first baffle plate in a flow of gas in the chamber. In at least a partial period of a waveform cycle of an electric bias energy periodically applied to a substrate support in the chamber, a value of a voltage that is applied to the second baffle plate is higher than a value of a voltage that is applied to the first baffle plate.