Substrate Stage Contamination Detection Using Focus Value Comparison
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Solution Overview
Problem
Conventional exposure apparatuses face reduced productivity due to the need to detect and remove foreign substances on substrate chucks, which disrupt overlay accuracy and require interrupting the exposure process.
Innovation Solution
A determining apparatus that compares focus measurement values between a first and second substrate stage to identify foreign substances on the substrate chuck, allowing for efficient detection without interrupting the exposure process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a determination process is performed using a reference substrate by interrupting an exposure process, then foreign substance detection accuracy is improved, but productivity is reduced
Solution Approach 1:
The system performs focus measurement on substrates before they are loaded onto the substrate chuck, or during the exposure process without interruption. By measuring focus values in advance or concurrently, the system eliminates the need to interrupt the exposure process for detection, thereby maintaining productivity while achieving accurate foreign substance detection through comparison of focus measurements.
Solution Approach 2:
The determination apparatus enables continuous exposure processing by performing focus measurements and foreign substance detections during the exposure process rather than interrupting it. The system continuously monitors focus values of substrates on the substrate chuck and compares them to reference values, allowing the exposure process to proceed without interruption while maintaining detection accuracy.
2Reliability
If focus measurement is performed on substrates to detect foreign substances, then detection reliability is improved, but process time is increased
Solution Approach 1:
Reference focus measurement values are pre-established and stored in the system. When a substrate is placed on the substrate chuck, its focus measurement is immediately compared against these pre-stored reference values, enabling rapid detection without requiring time-consuming reference measurements during the detection process itself.
Solution Approach 2:
The system continuously obtains focus measurement values from substrates on the substrate chuck, compares them with reference focus measurement values, and provides immediate feedback to determine the presence of foreign substances. This real-time feedback mechanism enables rapid detection decisions without extending the overall process time.
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
Enhances productivity by reducing the time needed for detecting and removing foreign substances on substrate chucks, maintaining overlay accuracy without interrupting the exposure process.
Implementation Method 1
a detection unit that measures a focus value of the substrate surface
Data Source
AI summary
In order to provide a determining apparatus capable of determining whether there is a foreign substance on a substrate stage with suppressing a decrease in productivity of an apparatus, the determining apparatus according to the present invention is configured to determine a state of a surface of each of a first substrate stage and a second substrate stage based on a first detection result of a substrate surface of a substrate mounted on the first substrate stage and a second detection result of the substrate surface of the substrate mounted on the second substrate stage.