Lithography Stage Thermal Deformation Compensation
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Solution Overview
Problem
The existing lithography apparatuses face challenges in maintaining accurate alignment between a mold and a substrate due to increased heat generation, which deforms the stage structure and position measurement systems, leading to longer alignment times and potential pattern shifts during the imprint process.
Innovation Solution
A lithography apparatus with a stage that moves while holding the substrate, equipped with a measurement unit to measure positional shifts and a control unit that corrects the target position based on measured shifts, allowing for sequential processing of shot regions to reduce initial positional errors and improve alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stage is speeded up and driven continuously to improve imprint process speed, then productivity increases, but heat generation deforms the stage structure and position measurement system, causing alignment accuracy to deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the measurement unit continuously monitors the position of the stage, and the control unit adjusts the target position based on measured positional shifts. This closed-loop feedback system compensates for thermal deformation in real-time, maintaining alignment accuracy despite continuous high-speed operation.
Solution Approach 2:
The control unit corrects the target position in advance based on previously measured positional shifts before performing the imprint process for each shot region. This preliminary correction prevents alignment errors from accumulating during continuous operation, enabling sustained high-speed processing without sacrificing precision.
2Loss of time
If the stage is driven at high speed, then processing time is reduced, but thermal deformation causes the initial shift amount between mold and substrate to increase, requiring longer alignment time
Solution Approach 1:
The measurement unit provides real-time feedback on positional shifts caused by thermal deformation, and the control unit uses this information to dynamically correct target positions. This feedback loop eliminates the need for lengthy alignment procedures even during high-speed operation.
Solution Approach 2:
The patent replaces mechanical alignment adjustment with a computational correction system. Instead of physically adjusting components to compensate for thermal drift, the system uses measurement data to calculate and apply positional corrections through the control unit, enabling faster alignment.
3Productivity
If continuous driving is used to maintain high speed, then productivity improves, but heat generation deforms the position measurement system (encoder), causing measurement accuracy to deteriorate
Solution Approach 1:
The system continuously measures the actual position using the encoder and compares it with the target position. When thermal deformation causes measurement errors, the feedback mechanism detects the discrepancy and the control unit compensates by adjusting subsequent target positions based on the measured shift pattern.
Solution Approach 2:
The control unit dynamically changes the target position parameter based on measured positional shifts. By adjusting the target position in response to thermal deformation, the system maintains measurement and control accuracy despite continuous high-speed operation that generates heat.
Data Source
AI summary
The present invention provides a lithography apparatus for performing a process of transferring a pattern of an original to each of shot regions two-dimensionally arrayed on a substrate, including a stage that moves while holding one of the substrate and the original, a measurement unit configured to measure, when performing the process, a positional shift amount between a mark provided on the original and a mark provided in each of the shot regions, and a control unit configured to control the process for the shot region so that after the process is performed successively for a plurality of first shot regions included in a first row, the process is performed successively for a plurality of second shot regions included in a second row adjacent to the first row.