RF Combiner-Distributor for Multi-Station Plasma Impedance Control
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Solution Overview
Problem
Existing plasma processing systems face challenges in efficiently adjusting impedances and power distribution across multiple plasma processing stations, leading to variability in plasma processing results and inefficiencies in multi-step processes.
Innovation Solution
A combiner and distributor system that splits non-50 ohm source signals and diverts power selectively to specific substrate stations, using active tunable elements and automated control to manage impedance transformations, RF signal amplitude, and phase, allowing for real-time adjustments and synchronization of plasma processing across multiple stations without turning off RF generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional separate RF generators are used for each plasma processing station, then each station can be independently controlled, but system complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple RF generators into a single shared RF source that distributes power to multiple plasma processing stations through a hybrid combiner/distributor network. This merging approach maintains independent station control through electronic switching and impedance matching while significantly reducing the total number of RF generators needed, thereby lowering system complexity and cost.
Solution Approach 2:
The hybrid combiner/distributor network serves multiple functions: it acts as a power distributor, an impedance matching network, and a station selection switch all in one system. This multi-functionality eliminates the need for separate control systems for each station while maintaining independent operation capability, resolving the contradiction between versatility and complexity.
2Productivity
If RF power is turned off between multi-layer processing steps, then process control is simplified, but productivity decreases due to processing interruptions
Solution Approach 1:
The patent enables continuous RF power delivery to the plasma processing system during multi-layer processing by using the hybrid combiner/distributor to dynamically redirect power between stations without shutting off the RF source. This continuous operation eliminates processing interruptions and maintains high productivity while the electronic switching provides precise process control for different layers.
Solution Approach 2:
The system uses dynamic electronic switching and real-time impedance matching in the hybrid combiner/distributor to adapt power distribution as processing transitions between different layers and stations. This dynamic control allows continuous operation while maintaining precise process control, resolving the contradiction between productivity and ease of operation.
3Adaptability or versatility
If standard 50 ohm RF systems are used, then system design is simplified, but impedance matching flexibility for multiple stations is insufficient
Solution Approach 1:
The patent implements variable impedance matching networks within the hybrid combiner/distributor that can dynamically adjust impedance values to match different plasma processing stations. This parameter change capability provides the necessary impedance matching flexibility for multiple stations with different load conditions while using standardized 50 ohm RF components, avoiding excessive system design complexity.
Solution Approach 2:
The hybrid combiner/distributor acts as an intermediary between the standard 50 ohm RF source and the various impedance loads of different plasma stations. This intermediary component provides impedance transformation and matching flexibility without requiring changes to the standard RF source design, resolving the contradiction between adaptability and design complexity.
4Adaptability or versatility
If power is diverted to dummy impedances for stations not needing power, then station selectivity is improved, but power distribution complexity increases
Solution Approach 1:
The patent extracts the station selection function into dedicated switching elements within the hybrid combiner/distributor that can isolate specific stations by connecting them to dummy impedances. This extraction of the switching function provides clean station selectivity while keeping the power distribution network itself relatively simple, as the switching logic is separated into distinct control elements.
Data Source
AI summary
Systems and methods for adjusting impedances or power or a combination thereof across multiple plasma processing stations are described. One of the systems includes a first radio frequency (RF) generator that generates a first RF signal having a first frequency, a second RF generator that generates a second RF signal having a second frequency, and a first matching network coupled to the first RF generator to receive the first RF signal. The first impedance matching network outputs a first modified RF signal upon receiving the first RF signal. The system further includes a second matching network coupled to the second RF generator to receive the second RF signal. The second matching network outputs a second modified RF signal upon receiving the second RF signal. The system further includes a combiner and distributor coupled to an output of the first matching network and an output of the second matching network.