In-line Ellipsometer Height Control for Large Sample Monitoring
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Solution Overview
Problem
Conventional systems for monitoring large samples using ellipsometers struggle with maintaining consistent height between the sample and the electromagnetic beam, leading to variable results due to changing distance, which is critical for accurate characterization.
Innovation Solution
A system comprising a moving sample stage with a conveyer system of rollers and a separate height monitoring and controlling system to maintain precise distance between the sample and the electromagnetic beam source and detector during real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large sample is mounted securely to a supporting stage for investigation, then the sample can be stable during measurement, but the sample cannot be moved during investigation and the system becomes complex
Solution Approach 1:
The patent transitions from a static mounting system to a dynamic conveyer system that continuously moves the sample through the measurement zone. The sample is mounted on a conveyer belt that transports it past the ellipsometer, allowing the sample to be moved during investigation rather than being stationary, thus resolving the contradiction between sample stability and movability.
Solution Approach 2:
The patent extracts the measurement function from the mounting structure. Instead of having the sample mounted on a complex stage with measurement capabilities, the sample is simply mounted on a conveyer and moved through a separate, dedicated measurement zone, separating the transport and measurement functions into independent components.
2Measurement precision
If the height distance between sample surface and electromagnetic beam source is not controlled, then the system is simpler to operate, but the measurement precision varies substantially with position
Solution Approach 1:
The patent implements a feedback control system where sensors continuously monitor the height position of the sample as it moves on the conveyer. This height information is fed back to a control mechanism that adjusts the position of the electromagnetic beam source or detector to maintain a constant height distance, ensuring measurement precision while using feedback to manage system complexity.
Solution Approach 2:
The patent replaces complex mechanical height adjustment mechanisms with a more sophisticated control system that uses sensors and actuators to dynamically maintain height. Instead of relying on purely mechanical fixtures, the system uses electronic sensing and control to manage the height dimension, reducing mechanical complexity while improving precision.
3Productivity
If continuous monitoring of a moving sample is performed, then productivity increases, but the height distance varies with position making data unreliable
Solution Approach 1:
The feedback control system continuously monitors sample height during movement and adjusts the beam source or detector position in real-time to maintain constant height distance. This ensures that data collected during continuous monitoring remains reliable, as the height parameter is actively controlled rather than allowing variation that would compromise data quality.
Solution Approach 2:
The system performs preliminary height adjustment and positioning before the sample enters the measurement zone, and continuously maintains this positioning during transport. By establishing and maintaining the correct height relationship in advance and throughout the measurement process, the system ensures reliable data acquisition during continuous monitoring.
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 continuous, accurate monitoring of large samples by maintaining consistent height, ensuring reliable data acquisition across multiple positions without altering the investigation position.
Implementation Method 1
a beam of electromagnetic radiation produced by a source thereof can be directed to interact with a surface of a sample
Implementation Method 2
applying ellipsometers, polarimeters, reflectometers and spectrophotometers, investigate samples using electromagnetic beams
Data Source
AI summary
A system for monitoring, in real time, relatively large samples as they are caused to pass by an ellipsometer or the like system, and method of its use.