RF Matching Circuit Preset for Fast Plasma Ignition Control
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Solution Overview
Problem
Existing plasma processes in semiconductor manufacturing face challenges in achieving precise control of plasma ignition and power delivery for advanced IC designs with feature sizes scaled down to a few nanometers, requiring fast and repeatable plasma ignition and power regulation to ensure uniformity and repeatability across large wafers.
Innovation Solution
A method involving pre-process configurations of the impedance matching circuit and signal generator settings to determine ignition and process frequencies, followed by automated plasma ignition and power regulation, minimizing mechanical adjustments during the actual plasma process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If variable components of the matching circuit are continuously adjusted during plasma processing, then plasma ignition and power delivery control is improved, but system complexity and processing time increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring the matching circuit with variable components (capacitors and inductors) set to specific positions before plasma ignition. The system determines optimal matching circuit configurations in advance based on expected plasma conditions, eliminating the need for continuous real-time adjustments during plasma processing. This pre-setting approach maintains plasma process repeatability while significantly reducing control system complexity.
Solution Approach 2:
The patent implements dynamics by making the matching circuit configurable across multiple discrete positions rather than fixed. The variable components can be adjusted to different configurations to match varying plasma conditions, providing the necessary adaptability. However, once configured for a specific plasma process, the matching circuit remains static during processing, combining the benefits of adaptability with operational simplicity.
2Manufacturing precision
If RF power is continuously delivered to sustain plasma, then plasma processing precision is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by delivering RF power in controlled pulses rather than continuous delivery. The system ignites plasma with an initial RF pulse, sustains it with periodic power delivery, and uses feedback from plasma diagnostics to regulate subsequent power pulses. This periodic approach maintains precise plasma control for feature dimension accuracy while reducing overall energy consumption compared to continuous RF power delivery.
Solution Approach 2:
The patent implements feedback by monitoring plasma conditions (such as impedance, power absorption, or optical emission) and using this information to adjust RF power delivery in real-time. The feedback loop ensures plasma is sustained at optimal power levels for precise manufacturing while avoiding excessive energy consumption. The system can detect plasma ignition and adjust power delivery accordingly, maintaining precision while optimizing energy use.
3Speed
If plasma ignition frequency is optimized for each process, then plasma ignition speed is improved, but system setup time and complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-determining optimal ignition frequencies for different plasma processes before actual processing begins. The system stores configuration data including optimal RF frequencies, power levels, and matching circuit settings for various plasma processes. When a specific plasma process is selected, the system automatically retrieves and applies the pre-optimized parameters, achieving fast plasma ignition without requiring real-time frequency optimization during setup.
Solution Approach 2:
The patent implements parameter changes by allowing the RF signal frequency to be adjusted to optimal values for different plasma conditions and process requirements. The system can modify frequency, power level, and matching circuit parameters based on the selected process type, gas composition, and chamber conditions. This flexibility enables optimized ignition speed for each specific process while maintaining efficient setup through pre-characterized parameter sets.
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
Enhances plasma process repeatability and reduces variability by ensuring efficient and rapid plasma ignition and power delivery, improving uniformity and throughput in semiconductor manufacturing.
Implementation Method 1
generating, at an output of a signal generator, a first RF signal at a first frequency
Implementation Method 2
generating, at the output of the signal generator, a second RF signal at a second frequency to ignite a plasma within the plasma chamber
Implementation Method 3
switching the signal generator to output a third RF signal at the first frequency, the third RF signal sustaining the plasma
Implementation Method 4
the signal generator being coupled to a plasma chamber through a matching circuit
Data Source
AI summary
A method of performing a plasma process includes generating, at an output of a signal generator, a first RF signal at a first frequency. The signal generator is coupled to a plasma chamber through a matching circuit. Based on a feedback from the first RF signal, variable components of the matching circuit are moved to fixed positions. A second RF signal is generated at a second frequency at the output of the signal generator to ignite a plasma within the plasma chamber. In response to detecting the plasma, the signal generator switches to output a third RF signal at the first frequency to sustain the plasma, which is configured to process a substrate loaded into the plasma chamber while holding the matching circuit at the fixed positions.