Lithography Stage Encoder Scale Holding Mechanism
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Solution Overview
Problem
The deformation of a stage in lithography apparatuses due to heat generated by high acceleration motors leads to a decrease in measurement accuracy of the encoder system, which is critical for precise pattern transfer on substrates.
Innovation Solution
A lithography apparatus with a stage mechanism that includes a scale holding portion capable of individually controlling attraction forces using multiple attractors, thereby maintaining the accuracy of the encoder system by minimizing deformation of the encoder scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stage is driven at high acceleration to improve article manufacturing throughput, then productivity is improved, but the stage deforms due to heat generated by the motor, causing measurement accuracy to decrease
Solution Approach 1:
The scale holding portion is divided into multiple independent attractors that can be individually controlled. This segmentation allows selective activation of only the attractors necessary for holding the encoder scale during measurement, while leaving other attractors inactive to minimize heat generation and stage deformation, thus maintaining measurement accuracy during high-speed operation
Solution Approach 2:
Different regions of the scale holding portion are assigned different functional qualities: some attractors are activated to provide holding force where needed, while other regions remain inactive to minimize thermal effects. This local differentiation of attraction states allows the system to maintain measurement precision in critical areas while managing overall heat generation to preserve productivity
2Measurement precision
If the encoder scale is held by attraction force to improve measurement accuracy, then measurement precision is improved, but the attraction force causes stage deformation, worsening measurement accuracy
Solution Approach 1:
The attraction force is made dynamic rather than static. The control unit selectively activates and deactivates individual attractors based on operational requirements. During high-speed movement, only necessary attractors are activated to provide minimal holding force, reducing thermal deformation. During measurement phases, attractors are activated to provide sufficient holding force for accurate measurement, thus dynamically balancing shape stability with measurement precision
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
The solution effectively suppresses the decrease in measurement accuracy caused by stage deformation, ensuring high-precision position measurement and pattern transfer on substrates.
Implementation Method 1
the scale holding portion includes a plurality of attractors capable of individually controlling attraction
Data Source
AI summary
A lithography apparatus that transfers a pattern of an original to a substrate, includes a stage mechanism including a stage configured to hold the substrate, and an encoder system including an encoder head and an encoder scale. The stage includes a scale holding portion configured to hold the encoder scale by an attraction force. The scale holding portion includes a plurality of attractors capable of individually controlling attraction.