Optical Collimator Tuning for Plasma Reflectometry Alignment
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Solution Overview
Problem
Plasma processing systems for semiconductor manufacturing face challenges in optimizing the orientation of optical collimators for spectral reflectometry systems, which affects the accuracy of spectral intensity measurements and subsequently the control of plasma processing parameters.
Innovation Solution
A method is disclosed for tuning the orientation of an optical collimator in a plasma processing system, involving raster scans and a slope-ascent search process to identify the optimal tip and tilt angles that maximize spectral intensity measurements, allowing for precise adjustment and alignment within the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical collimator orientation is not precisely tuned, then the system structure remains simple, but the spectral intensity measurement accuracy deteriorates
Solution Approach 1:
The system performs self-tuning of the optical collimator orientation through automated raster scans and slope-ascent search algorithms. The collimator automatically adjusts its tip and tilt angles to maximize spectral intensity measurements without requiring manual intervention, thereby achieving high measurement accuracy while maintaining operational simplicity.
Solution Approach 2:
The system implements a feedback mechanism where spectral intensity measurements are continuously monitored and used to adjust the collimator orientation. The slope-ascent search process uses measurement feedback to iteratively optimize the tip and tilt angles, ensuring maximum spectral intensity is captured while automating the tuning process.
2Manufacturing precision
If manual tuning methods are used, then the system complexity remains low, but the plasma processing parameter control accuracy deteriorates
Solution Approach 1:
The patent replaces manual mechanical tuning with an automated optical-tuning system controlled by computer algorithms. The raster scan and slope-ascent search processes use computational methods to determine optimal collimator angles, substituting human operation with automated systems that provide superior precision for plasma processing parameter control.
Solution Approach 2:
The system systematically varies the collimator's tip and tilt angle parameters during raster scans to explore the orientation space. By changing these angular parameters in a structured manner and analyzing the resulting spectral intensity variations, the system automatically identifies optimal settings that maximize measurement accuracy for precise plasma parameter control.
3Measurement precision
If the collimator orientation is imprecise, then the tuning process remains simple, but the spectral intensity measurement accuracy deteriorates
Solution Approach 1:
The collimator tuning system operates autonomously through self-service mechanisms. The automated raster scan and slope-ascent search algorithms perform the entire tuning process without user intervention, systematically adjusting tip and tilt angles to maximize spectral intensity measurements while maintaining ease of operation through full automation.
Solution Approach 2:
The system performs preliminary raster scans to map the spectral intensity landscape before executing the final optimization. This preliminary action identifies the general orientation region, allowing the subsequent slope-ascent search to efficiently converge on the precise optimal angles, thereby achieving high measurement accuracy while streamlining the overall tuning operation.
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 enhances the accuracy of spectral intensity measurements, enabling better control over plasma processing parameters and improving the efficiency and precision of semiconductor wafer processing.
Implementation Method 1
The optical collimator is also configured to receive reflected light from within the plasma processing chamber, where the reflected light passes through the upper window
Implementation Method 2
spectral reflectometry system disposed within the metrology enclosure. The spectral reflectometry system includes an optical collimator positioned to direct a beam of light
Data Source
AI summary
A plasma processing chamber has an upper window with a coil disposed above the upper window. A coil connection enclosure is disposed above the coil. A metrology enclosure is disposed above the coil connection enclosure. A spectral reflectometry system is disposed within the metrology enclosure. The spectral reflectometry system includes an optical collimator positioned to direct a beam of light through an opening in the metrology enclosure, an opening in the coil connection enclosure, and the upper window into the plasma processing chamber. The optical collimator is also configured to receive reflected light from within the plasma processing chamber, where the reflected light passes through the upper window and through the opening in the coil connection enclosure and through the opening in the metrology enclosure. A tip angle and a tilt angle of the optical collimator are remotely adjusted to optimize an orientation of the optical collimator.