Lithography Optics Monitoring via Fluorescent Beam Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The optical elements in laser-generated light sources used for semiconductor photolithography deteriorate over time, leading to performance decline and requiring frequent maintenance, which results in prolonged downtime and increased costs due to the inability to detect optical degradation mechanisms like slip planes, line damage, point-like defects, and dendritic formations in situ.
Innovation Solution
The implementation of electrically operated and controlled alignment actuators, optical sensors such as cameras for fluorescent alignment screens, and a combined autoshutter metrology module (CASMM) for imaging the laser beam at multiple points along the optical path, allowing for dynamic alignment and real-time monitoring of optical performance, detection of defects, and prediction of maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection methods are used to detect optical defects, then defect detection is possible, but the system must be taken offline and downtime increases
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical detection system using cameras and image processing algorithms. This substitution enables continuous in-situ monitoring of optical components without requiring system shutdown, thereby eliminating downtime while maintaining high defect detection precision through automated image analysis
Solution Approach 2:
The system implements self-diagnostic capabilities where the optical detection system automatically monitors and identifies defects in optical components during operation. The automated nature of the system allows it to perform its own health assessment without external intervention or system shutdown, enabling continuous operation while maintaining detection accuracy
2Reliability
If frequent maintenance is performed to address optical degradation, then optical performance is maintained, but productivity decreases due to prolonged downtime
Solution Approach 1:
The patent implements predictive maintenance by continuously monitoring optical components for early signs of degradation such as slip planes, dendrites, and coating damage. By detecting these defects in advance during operation, the system allows for planned maintenance scheduling that minimizes production disruption while ensuring optical performance is maintained before degradation becomes severe
Solution Approach 2:
The system establishes a feedback loop where optical detection data is continuously analyzed to assess component health status. This feedback mechanism enables dynamic adjustment of maintenance schedules based on actual component condition rather than fixed intervals, allowing extended operation between maintenance events when components are healthy while ensuring timely intervention when degradation is detected, thereby maintaining productivity
3Reliability
If real-time monitoring systems are implemented to detect optical defects, then maintenance needs can be predicted, but device complexity increases
Solution Approach 1:
The patent employs a multi-functional optical detection system that uses the same camera and image processing infrastructure to detect multiple types of defects including slip planes, dendrites, coating damage, and contamination. This universal approach consolidates what would otherwise require multiple specialized sensors into a single system, reducing overall complexity while maintaining comprehensive monitoring and prediction capabilities
Solution Approach 2:
The system introduces software-based image processing algorithms as an intermediary layer between the simple camera sensor and the complex task of defect detection. These algorithms automatically identify and classify various defect types from captured images, enabling reliable maintenance prediction without requiring complex hardware for each specific defect type, thus managing system complexity through intelligent software mediation
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 approach reduces downtime by enabling in-situ detection and monitoring of optical degradation, extending the operational life of modules and optics, and improving scanner performance by allowing adjustments during production pauses, thus minimizing the need for costly maintenance and realignment.
Implementation Method 1
an image of the laser beam is obtained on a fluorescent alignment screen
Data Source
AI summary
Methods and apparatus for processing an image of a beam generated by an optical system to extract information indicative of an extent of damage to optical elements in the optical system. Also disclosed is a beam image and analysis tool capable of acquiring an image of a beam at any one of a number of locations.