Multi-Frequency RF Feeding for Uniform Plasma Distribution
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Solution Overview
Problem
Large area processing chambers for flat panel displays and solar panels face challenges with substrate throughput and deposition uniformity due to standing waves caused by RF voltage, leading to non-uniform plasma distribution and subsequent deposition or etching issues.
Innovation Solution
Applying RF voltage at multiple points with different frequencies, allowing the interference wave pattern to move across the electrode, thereby achieving a substantially uniform plasma distribution over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If RF voltage is applied at a single location and frequency to process large area substrates, then the processing chamber can handle large substrates, but standing waves cause non-uniform plasma distribution and deposition uniformity issues
Solution Approach 1:
The patent divides the single RF voltage application into multiple separate RF voltage applications at different locations on the electrode. By segmenting the RF power input into multiple spatial zones, the standing wave patterns that cause non-uniform plasma distribution are reduced, enabling uniform processing across large area substrates while maintaining the ability to handle large substrate sizes
Solution Approach 2:
The patent changes the frequency parameter of the RF voltage by applying voltages at multiple different frequencies simultaneously. This frequency diversification disrupts the formation of stable standing wave patterns, thereby eliminating plasma non-uniformity and deposition inconsistencies while preserving large substrate processing capability
2Area of stationary object
If chamber volume is increased to process larger substrates, then substrate area capacity increases, but substrate throughput and deposition uniformity deteriorate
Solution Approach 1:
By segmenting the RF power application into multiple independent locations and frequencies, the system achieves uniform plasma distribution across large chambers without sacrificing throughput. This segmentation allows parallel processing efficiency while maintaining uniformity, resolving the trade-off between chamber size and productivity
Solution Approach 2:
The patent introduces dynamic frequency variation by applying multiple RF voltages at different frequencies simultaneously. This dynamic approach prevents stationary standing wave patterns from forming, enabling consistent plasma uniformity across large substrate areas while maintaining high processing throughput
3Manufacturing precision
If RF voltage is applied at multiple points at different frequencies, then plasma uniformity improves, but device complexity increases
Solution Approach 1:
The patent segments the RF power system into multiple independent power sources or feed points, each operating at different frequencies. This segmentation achieves superior plasma uniformity by eliminating standing waves, while the modular nature of segmented RF inputs makes the increased complexity manageable through standardized components
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 uniform plasma distribution, reducing non-uniformities in material deposition or etching across large substrates, enhancing processing consistency and quality.
Implementation Method 1
By applying RF voltage in at least two separate locations at two separate, but close frequencies, the interference wave pattern moves across the electrode
Implementation Method 2
standing waves (interference wave patterns) can lead to deposition and/or etching non-uniformities
Implementation Method 3
igniting the gas into a plasma and processing the substrate with the plasma
Implementation Method 4
plasma enhanced chemical vapor deposition method
Data Source
AI summary
Embodiments disclosed herein generally relate to obtaining a substantially uniform plasma distribution within a large area processing chamber. For large area processing chambers that utilize RF voltages, standing waves can lead to deposition and/or etching non-uniformities. By applying RF voltage in at least two separate locations at two separate, but close frequencies with or without phase modulation, the wave interference pattern moves across the electrode. By moving the standing wave across the electrode, the plasma generated in the chamber can, over time, be substantially uniform.