Plasma Source Feedback Control Using Laser Absorption Sensing
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Solution Overview
Problem
Current plasma processing tools lack closed-loop control systems, relying on historical data and dummy substrates for adjustments, leading to unpredictable substrate performance and significant yield losses due to chamber drift and inability to constantly monitor tool performance.
Innovation Solution
Implementing a laser absorption species sensor that uses laser absorption spectroscopy to measure radical species concentration in the plasma chamber, allowing for real-time feedback to adjust process parameters such as gas flow rate, power, frequency, pressure, and temperature to maintain desired species concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If historical data and dummy substrates are used to adjust plasma parameters, then process control is simplified, but substrate performance consistency deteriorates due to chamber drift
Solution Approach 1:
The patent implements real-time feedback control by continuously monitoring radical species concentration with a laser absorption sensor and automatically adjusting plasma parameters (power, gas flow, pressure) to maintain target concentration, eliminating chamber drift and ensuring consistent substrate performance without complex manual intervention
Solution Approach 2:
The patent replaces the mechanical/manual process of adjusting plasma parameters based on historical data and dummy substrates with an automated optical sensing and control system that uses laser absorption spectroscopy to directly measure and control radical species concentration in real-time
2Device complexity
If no real-time monitoring of radical species is implemented, then device complexity is reduced, but process control reliability deteriorates due to inability to detect chamber drift
Solution Approach 1:
The laser absorption sensor provides continuous real-time feedback on radical species concentration, enabling immediate detection of chamber drift and automatic correction through plasma parameter adjustment, ensuring reliable process control without requiring complex periodic monitoring systems
Solution Approach 2:
The patent introduces a laser beam as an intermediary probe that penetrates the plasma chamber to directly measure radical species concentration without physically interfering with the plasma process, providing reliable real-time data while maintaining process integrity
3Manufacturing precision
If closed-loop plasma control is implemented, then substrate performance consistency is improved, but device complexity increases due to need for real-time monitoring and adjustment systems
Solution Approach 1:
The system uses laser absorption spectroscopy to provide real-time feedback on radical species concentration and automatically adjusts plasma parameters (power, gas flow rate, pressure) to maintain target concentration, ensuring consistent substrate performance through precise closed-loop control
Solution Approach 2:
The patent dynamically changes plasma process parameters (power, gas flow rate, pressure) in real-time based on measured radical species concentration to maintain optimal processing conditions and ensure consistent substrate performance
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
Enables precise control of plasma processes, reducing yield losses and chamber matching issues by providing continuous monitoring and adjustment, thereby improving the consistency and efficiency of substrate processing.
Implementation Method 1
a laser source to propagate a laser through the chamber, and detecting the laser with a detector after the laser passes through the chamber
Implementation Method 2
detecting an absorption of the laser with the detector after the laser passes through the chamber
Data Source
AI summary
Embodiments disclosed herein include a semiconductor processing tool. In an embodiment, the semiconductor processing tool comprises a chamber, a pedestal in the chamber configured to secure a substrate, and a plasma source above the pedestal. In an embodiment, a laser source is coupled to the chamber, and a detector is coupled to the chamber across from the laser source. In an embodiment, the detector is configured to be optically coupled to the laser source.