Planar Motor Stage Reducing Pitching Moment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional stage devices for semiconductor manufacturing experience instability due to pitching moments generated during wafer movement, which affects precision and throughput in lithography processes.
Innovation Solution
A movable body apparatus with a second movable body forming a frame around the first movable body, supported by planar motors, reduces the height and thus the pitching moment by placing the thrust point closer to the center of gravity, allowing for more stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the substrate table is driven by a planar motor with the mover fixed to the bottom portion of the substrate table, then the drive force can be applied directly to the substrate table, but the pitching moment is generated due to the height difference between the center of gravity and the bottom surface, causing operational instability
Solution Approach 1:
The invention transitions from a conventional single-stage configuration to a two-stage hierarchical structure. The substrate table is divided into a first movable body (coarse movement stage) and a second movable body (fine movement stage) that moves relative to the first. This dimensional restructuring allows the planar motor to drive the first movable body while the second movable body performs fine positioning, thereby reducing the pitching moment's impact on overall stability while maintaining drive effectiveness.
2Manufacturing precision
If a coarse/fine movement configuration is used with the fine movement stage mounted on the coarse movement stage, then high-precision positioning can be achieved, but the height of the movable body increases, which may exacerbate the pitching moment issue
Solution Approach 1:
The invention implements a nested configuration where the second movable body (fine movement stage) is positioned within the periphery of the first movable body (coarse movement stage). The second movable body is supported by the first, creating a compact hierarchical structure. This nesting approach achieves high positioning precision through the fine movement stage while keeping the overall height minimized, as the fine movement stage operates within the spatial envelope of the coarse movement stage rather than stacking vertically.
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 configuration enhances the stability and precision of wafer movement, improving the throughput and accuracy in semiconductor manufacturing processes by minimizing pitching moments and allowing for more efficient exposure operations.
Implementation Method 1
a planar motor by an electromagnetic force drive method has been developed
Implementation Method 2
an actuator that drives the first movable body with respect to the second movable body
Data Source
AI summary
A stage device is equipped with a fine movement stage on which a wafer is mounted, a coarse movement stage formed into a frame shape that encloses the periphery of the fine movement stage, which supports the fine movement stage such that the fine movement stage is relatively movable and which is movable along an XY plane, a planar motor that drives the coarse movement stage in a predetermined range within the XY plane, and an actuator that drives the fine movement stage with respect to the coarse movement stage. Therefore, the size, in a direction perpendicular to the XY plane (height direction), of a movable body made up of the fine movement stage and the coarse movement stage can be reduced, compared with a wafer stage having a coarse/fine movement configuration in which the fine movement stage is mounted on the coarse movement stage.