Multi-Point Angular Scatterometry for Real-Time Roll-to-Roll Metrology
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Solution Overview
Problem
Existing metrology tools for roll-to-roll manufacturing of nanoscale structures are not suitable for real-time, high-speed monitoring due to their off-line operation and incompatibility with flexible substrates, leading to challenges in providing feedback for dynamic manufacturing processes.
Innovation Solution
A high-speed 2θ multi-point scatterometry system using collimated laser beams with dynamically variable angles of incidence, combined with resonant scanners and optical elements like parabolic or acylindrical mirrors, to scan and measure multiple points on a sample surface simultaneously, allowing for real-time monitoring of nanoscale structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If off-line metrology tools are used for nanoscale structure measurement, then measurement precision can be achieved, but real-time monitoring capability is lost
Solution Approach 1:
The system transitions from static off-line measurement to dynamic real-time monitoring by implementing a moving web configuration where the substrate continuously moves through the measurement zone. The resonant scanners dynamically adjust beam positions to track multiple points across the moving substrate, enabling real-time feedback while maintaining measurement precision through synchronized scanning motion.
Solution Approach 2:
The patent implements continuous measurement by using a moving web configuration where substrates are continuously fed through the system. Multiple laser beams simultaneously measure multiple points on the moving substrate, ensuring uninterrupted real-time monitoring without stopping the manufacturing process, thus eliminating idle time between measurements.
2Measurement precision
If single-point measurement is used, then measurement precision is maintained, but productivity decreases due to sequential scanning requirements
Solution Approach 1:
The measurement system is divided into multiple independent measurement channels, each with its own laser beam and detector. These segmented measurement points operate simultaneously on different locations of the substrate, allowing parallel data collection that maintains precision at each point while dramatically increasing overall throughput by measuring multiple points concurrently.
Solution Approach 2:
The patent combines multiple single-point measurement systems into a unified multi-point measurement platform. By merging several laser sources, scanning systems, and detectors into a single integrated instrument, the system achieves both the precision of individual point measurements and the productivity of simultaneous multi-point operation.
3Adaptability or versatility
If flexible substrates are used in roll-to-roll manufacturing, then manufacturing versatility is improved, but measurement stability deteriorates due to substrate stretching and vibrations
Solution Approach 1:
The system is designed to dynamically adapt to substrate motion by using resonant scanners that synchronize their scanning frequency with the substrate feed rate. This dynamic synchronization compensates for substrate stretching and vibrations, maintaining measurement stability on flexible moving substrates while preserving the versatility of roll-to-roll manufacturing.
Solution Approach 2:
The patent implements real-time feedback control where measurement data from the moving substrate is immediately processed and used to adjust scanning parameters and measurement timing. This closed-loop feedback system compensates for substrate motion variations, ensuring reliable measurements on flexible substrates undergoing stretching and vibration during roll-to-roll processing.
4Measurement precision
If ellipsometric scatterometry with broadband incoherent source is used, then sensitivity to nanoscale features is improved, but measurement time increases due to power density restrictions
Solution Approach 1:
The system combines the advantages of both ellipsometric scatterometry (high sensitivity through polarization measurement) and angular scatterometry (fast response through high power density laser source). By making the system multi-functional—capable of both polarization analysis and angular scanning—it achieves nanoscale sensitivity without the measurement time penalty, as the high brightness laser provides sufficient power for rapid polarization measurements.
Solution Approach 2:
The patent changes the light source parameter from broadband incoherent to coherent laser, and simultaneously changes the measurement parameter from purely spectral to angular plus polarization. This parameter transformation allows the system to achieve comparable or superior sensitivity with much faster measurement times, as the coherent laser's high brightness enables rapid data collection while angular scanning provides additional measurement dimensions.
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 real-time, high-speed monitoring of nanoscale structures on flexible substrates, providing accurate feedback for manufacturing processes by scanning multiple points across the sample surface with enhanced sensitivity and reduced measurement time.
Implementation Method 1
scatterometry, the measurement of light reflected/transmitted/scattered from a sample with a nanoscale structured array
Implementation Method 2
scatterometry, the measurement of light reflected/transmitted/scattered from a sample with a nanoscale structured array
Implementation Method 3
offers much higher power densities, allowing larger bandwidth receivers to accommodate higher speeds
Data Source
AI summary
A method and system for high-speed 2θ multi-point scatterometry is disclosed. The method includes directing a laser beam from a laser light source to a collimation optical system that collimates the laser beam to a collimated laser beam; adjusting a polarization of the collimated laser beam using a polarization control optics; directing the collimated laser beam that is polarized by a first optical system to illuminate a focal area on a sample surface; receiving reflected light from the focus of the laser light source at the sample surface by a second optical system; detecting the reflected light by a detector system to produce detection signals; and processing the detection signals to measure parameters of the sample surface.