Multi-Column Optical Measurement System for Semiconductor Wafer Inspection
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Solution Overview
Problem
Existing optical measurement systems with a single measurement column and translation stage have limited measurement throughput, making them inefficient for semiconductor fabrication, which requires fast movement speeds and low settling times.
Innovation Solution
A measurement system with multiple sets of optical sub-systems and a unified sample positioning assembly, featuring coarse and fine translation stages, allows for simultaneous independent measurements on multiple samples with improved resolution and positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single measurement column and single translation stage are used, then the system complexity is low, but the measurement throughput is limited
Solution Approach 1:
The system divides the measurement function into multiple independent measurement columns (first, second, and third measurement columns), each capable of independently measuring different samples. This segmentation allows parallel measurements to occur simultaneously across multiple samples, directly increasing measurement throughput while maintaining manageable complexity through modular architecture
Solution Approach 2:
Multiple measurement columns are merged with a shared coarse translation stage that supports multiple fine translation stages. This combining approach allows the system to achieve high throughput through parallel measurement while reducing overall complexity by sharing common positioning infrastructure rather than requiring completely independent systems for each measurement column
2Productivity
If translation stages with fast movement speeds and low settling times are used, then measurement throughput is improved, but the cost becomes prohibitive
Solution Approach 1:
The translation stage function is segmented into two independent levels: a coarse translation stage for positioning multiple fine translation stages, and individual fine translation stages for precise sample positioning under each measurement column. This segmentation allows each component to be optimized independently, reducing the need for expensive high-performance stages across the entire system
Solution Approach 2:
The system adds a hierarchical dimension to the translation mechanism by implementing coarse positioning at one level and fine positioning at another level. This multi-dimensional approach allows the coarse stage to handle large movements at lower cost, while the fine stages handle only small precision adjustments, significantly reducing the overall cost compared to using a single high-performance stage for all positioning requirements
3Productivity
If a single fine translation stage is used for one sample, then the positioning accuracy is good, but the measurement throughput is limited
Solution Approach 1:
The positioning function is segmented between a coarse translation stage that positions multiple fine translation stages, and individual fine translation stages that independently position samples under each measurement column. This segmentation enables multiple samples to be positioned with high accuracy simultaneously, achieving both high throughput and high precision through parallel operation of multiple fine positioning stages
Solution Approach 2:
The system implements dynamic coordination between the coarse translation stage and multiple fine translation stages. The coarse stage dynamically positions the fine stages to appropriate locations, and the fine stages independently adjust their positions for precise measurement alignment. This dynamic hierarchical control allows the system to maintain high positioning accuracy across multiple simultaneously measured samples
Data Source
AI summary
A measurement system may include two or more sets of optical sub-systems to simultaneously generate measurement data on two or more samples, a coarse translation stage providing motion along a plane, two or more fine translation stages disposed on the coarse translation stage arranged in a common pattern as the two or more sets of optical sub-systems, where each of the fine translation stages provides motion along the plane and is arranged to position one of the two or more samples under one of the two or more sets of optical sub-systems. The system may further include a controller to independently direct each of the fine translation stages and the associated one of the optical sub-systems to generate measurement data for the respective samples, and generate one or more measurements for the samples based on the associated measurement data.