Substrate Support Scanning for Faster Alignment and Height Mapping
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Solution Overview
Problem
Existing exposure apparatuses in lithographic technology face challenges in optimizing the measurement time and accuracy of substrate alignment and height mapping processes, which affect overall throughput and precision in semiconductor manufacturing.
Innovation Solution
A substrate support compartment with integrated level and alignment sensors, controlled by a unit that manages the displacement of the substrate along a predefined path, allowing simultaneous or interleaved determination of alignment marks and height maps, optimizing the scanning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sequential processes are used for alignment measurement and height map scanning, then measurement accuracy can be maintained, but total measurement time increases and throughput decreases
Solution Approach 1:
The patent merges the alignment measurement process and height map scanning process into a single integrated measurement process. The control algorithm coordinates both sensors to operate simultaneously during substrate displacement, combining two previously separate sequential processes into one concurrent operation, thereby reducing total measurement time while maintaining measurement accuracy
Solution Approach 2:
The patent implements continuous measurement action by coordinating the substrate displacement with simultaneous operation of both alignment sensor and height map sensor. The control algorithm ensures that measurement activities continue without interruption or idle time, eliminating the gaps that would occur in sequential processes and maximizing throughput
2Productivity
If multiple sensors operate simultaneously during substrate displacement, then throughput increases, but coordination complexity and control difficulty increase
Solution Approach 1:
The patent employs dynamic control algorithms that adaptively coordinate the movement and measurement activities of multiple sensors. The control system dynamically adjusts substrate displacement patterns, sensor activation timing, and data collection rates to optimize throughput while managing coordination complexity through real-time feedback and adaptive control strategies
Solution Approach 2:
The patent utilizes parameter changes in the control algorithm to manage multiple sensors efficiently. By dynamically adjusting measurement parameters such as scanning speed, sensor activation sequences, and data sampling rates, the system coordinates complex multi-sensor operations while maintaining optimal throughput and managing computational complexity
3Loss of time
If the substrate is moved quickly across the measurement area, then measurement time decreases, but measurement accuracy and precision deteriorate
Solution Approach 1:
The patent implements periodic measurement action patterns where the substrate undergoes controlled displacement cycles. The control algorithm orchestrates periodic scanning motions that optimize the balance between speed and accuracy, using rhythmic measurement intervals to capture alignment data and height map data at optimal sampling rates that maintain precision while minimizing total measurement time
Data Source
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AI summary
A substrate support compartment for an exposure apparatus comprising a substrate support assembly, a level sensor, an alignment sensor, and a control unit. The substrate support assembly comprises a movable substrate support configured to support a substrate. The control unit is configured to control the movable substrate support to displace the substrate relative to the level sensor according to a predefined path in order for the level sensor to determine a substrate height map. The control unit is further configured to control the movable substrate support to adjust the displacement of the substrate at an adjustment point along the predefined path in order for the alignment sensor to determine a position of an alignment mark which is arranged at or near the adjustment point along the predefined path.