Non-Invasive IEDF Plasma Sensing for Real-Time RF Control
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Solution Overview
Problem
Current RF generator systems in plasma fabrication lack precise control over ion energy distribution and plasma parameters, leading to inefficiencies in etching and deposition processes, particularly in semiconductor fabrication, where invasive sensors disturb the plasma and real-time, non-invasive monitoring is challenging.
Innovation Solution
A controller system that integrates model evaluation, ion energy distribution function (IEDF) generation, and RF generator control to adjust power, frequency, or phase of RF generators based on sensed plasma parameters, enabling non-invasive, real-time control of plasma conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive sensors are used to monitor plasma parameters, then measurement precision is improved, but the plasma is disturbed and process reliability deteriorates
Solution Approach 1:
The patent introduces an optical intermediary (light) to transfer information about plasma parameters without physical contact. The optical system acts as a mediator that allows measurement of plasma characteristics through light interaction, eliminating the need for invasive physical sensors that would disturb the plasma environment.
Solution Approach 2:
The patent replaces mechanical/invasive sensing methods with optical measurement techniques. Instead of using physical sensors that mechanically interact with the plasma, the system uses optical fields to probe plasma parameters, substituting a non-contact optical system for a contact-based mechanical sensing approach.
2Manufacturing precision
If real-time monitoring is implemented, then control precision is improved, but system complexity increases due to the need for sophisticated sensing and control systems
Solution Approach 1:
The patent extracts only the essential measurement information needed for control by using optical methods to selectively probe specific plasma parameters. This extraction approach obtains necessary data without requiring complex sensor arrays, simplifying the overall system while maintaining real-time monitoring capability.
Solution Approach 2:
The patent creates an optical copy or representation of plasma parameters through light interaction. Instead of directly measuring complex plasma properties with sophisticated sensors, the system uses optical signals that replicate or represent plasma state information, enabling simpler measurement and control systems.
3Productivity
If RF generator power is increased to improve etching efficiency, then productivity is improved, but ion energy distribution control precision deteriorates
Solution Approach 1:
The patent implements a feedback control system that uses real-time optical monitoring of plasma parameters to dynamically adjust RF generator settings. This closed-loop feedback enables the system to maintain precise ion energy distribution control even at higher power levels, allowing increased productivity without sacrificing precision.
Solution Approach 2:
The patent introduces dynamic control of RF generator parameters based on real-time plasma conditions. Instead of static power settings, the system dynamically adjusts power, frequency, and phase parameters in response to monitored plasma state, enabling efficient operation across varying conditions while maintaining control precision.
Data Source
AI summary
A controller for a plasma generation system includes a model evaluation module receives a sensed value that varies in accordance with a state of a plasma controlled by a RF power generator. The model evaluation module generates a plasma parameter that varies in accordance with the sensed value. A model integration module receives the plasma parameter, integrates the plasma parameter, and outputs an integrated model parameter. An IEDF evaluation module receives the integrated model parameter and generates an ion energy distribution function (IEDF) in accordance with the integrated model parameter. An IEDF controller module receives the IEDF and generates a signal for controlling a RF generator. A RF generator control module receives the signal and generates an RF generator control signal to control at least one of power, frequency, or phase of the RF power generator.