Strain Sensor Measurement Substrate for Lithographic Wear Detection
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Solution Overview
Problem
The existing methods for detecting wear of substrate holders in lithographic apparatuses are time-consuming and disruptive to production, as they require removing the substrate holder and using techniques like confocal microscopy or specific test exposures, which reduce throughput and cause excessive downtime.
Innovation Solution
A measurement substrate with a body similar in dimensions to the production substrate, equipped with strain sensors, is clamped to the substrate holder to quickly measure strain, allowing for rapid detection of wear without disrupting the lithographic apparatus operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If confocal microscopy or specific test exposures are used to detect substrate holder wear, then measurement precision is improved, but productivity deteriorates due to excessive downtime and disruption to production
Solution Approach 1:
The measurement substrate is prepared in advance with embedded strain sensors before being clamped to the substrate holder. This preliminary preparation allows wear detection to occur rapidly during scheduled maintenance intervals without requiring time-consuming confocal microscopy scans or test exposures, thus maintaining productivity while achieving accurate wear measurement through the pre-configured sensor system
Solution Approach 2:
The patent replaces complex optical measurement systems (confocal microscopy) and iterative test exposure procedures with a straightforward mechanical strain sensing system. Strain sensors directly attached to the measurement substrate provide immediate wear detection data through electrical resistance changes, eliminating the need for time-consuming optical scanning or multiple test exposures while maintaining measurement accuracy
2Measurement precision
If the substrate holder is removed for wear detection, then measurement precision is improved, but loss of time increases due to apparatus disruption and reinstallation
Solution Approach 1:
The measurement substrate with embedded strain sensors serves itself by continuously monitoring its own strain state when clamped to the substrate holder. The strain sensors automatically detect wear-induced deformations without requiring external measurement equipment or apparatus disruption, enabling rapid wear assessment that eliminates time loss from removing and reinstalling the substrate holder
Solution Approach 2:
The measurement substrate serves multiple functions: it acts as both a test specimen and a sensor carrier simultaneously. By integrating strain sensors directly onto the substrate, the system eliminates the need for separate measurement equipment and apparatus disassembly, achieving accurate wear detection while minimizing downtime through this multi-functional design
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 method enables quick and accurate detection of substrate holder wear, reducing downtime and providing detailed information on wear distribution and history, thereby improving wafer loading and cleaning processes to minimize wear, and allowing for predictive maintenance.
Implementation Method 1
measuring strain in the measurement substrate to generate a measurement result
Data Source
AI summary
A method of measuring wear of a substrate holder that is configured to hold a production substrate, the method includes: clamping a measurement substrate to the substrate holder; and measuring strain in the measurement substrate to generate a measurement result. The measurement substrate may have a body having dimensions similar to that of the production substrate; and a strain sensor in the body configured to measure strain in a peripheral portion of the measurement substrate.