Wafer Stage Vibration Damping via Squeeze Film Mechanism
Solution Overview
Problem
Conventional lithography processes for semiconductor and liquid crystal display device manufacturing using step-and-repeat or step-and-scan exposure apparatuses face challenges with the coarse/fine movement separate type stage, which increases device complexity, weight, and cost due to the need for multiple stages and wiring, while also risking positioning accuracy due to thermal deformation and vibration during stage drive.
Innovation Solution
A movable body apparatus with a vibration-damping section between the base member and the holding member to suppress vibrations and reduce deformation, integrated into an exposure apparatus that uses a planar motor for movement in six degrees of freedom, and a voice coil motor for precise positioning, eliminating the need for separate coarse and fine movement stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coarse/fine movement separate type stage is used, then positioning accuracy is improved, but device complexity and weight increase due to multiple stages and wiring
Solution Approach 1:
The patent merges the coarse movement stage and fine movement stage into a single integrated wafer stage. The stage incorporates both coarse positioning mechanisms (linear motors for large movements) and fine positioning mechanisms (voice coil motors for precise adjustments) within one unified structure, eliminating the need for separate stages and reducing overall device complexity while maintaining positioning accuracy.
Solution Approach 2:
The integrated wafer stage is designed to perform multiple functions: it provides both coarse movement capability through linear motors and fine positioning capability through voice coil motors, while also serving as a single platform for substrate handling. This multi-functional design reduces the number of separate components needed and simplifies the overall system architecture.
2Measurement precision
If a coarse/fine movement separate type stage is used, then positioning accuracy is improved, but weight increases due to multiple stages and cables
Solution Approach 1:
The patent combines multiple movement stages into one integrated stage structure, eliminating redundant components and connecting elements such as separate cables and piping. This consolidation significantly reduces the overall weight of the moving object while preserving both coarse and fine positioning capabilities within the unified stage.
3Device complexity
If a single integrated stage is used, then device complexity is reduced, but positioning accuracy may decrease due to vibration and thermal deformation
Solution Approach 1:
The patent introduces vibration damping sections as intermediary elements between the stage components and the substrate table. These damping sections act as mediators that absorb and reduce vibrations generated during stage movement, preventing them from affecting positioning accuracy. The vibration damping sections are strategically placed at multiple locations within the integrated stage structure.
Solution Approach 2:
The patent employs materials with specific thermal properties and structural designs that minimize thermal deformation effects. By carefully selecting materials and designing the stage structure to compensate for thermal expansion, the system maintains positioning accuracy despite the integrated design that generates more internal heat.
4Weight of moving object
If a single integrated stage is used, then weight is reduced, but positioning accuracy may decrease due to vibration during drive
Solution Approach 1:
The patent introduces vibration damping sections as intermediary elements between the stage components and the substrate table. These damping sections act as mediators that absorb and reduce vibrations generated during stage movement, preventing them from affecting positioning accuracy. The vibration damping sections are strategically placed at multiple locations within the integrated stage structure.
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 enhances positioning accuracy and reduces device complexity and weight by integrating vibration-damping and using a single stage for precise movement in six degrees of freedom, improving exposure precision and manufacturing efficiency.
Implementation Method 1
a vibration-damping section placed between the base member and the holding member that suppresses vibration of the supporting member
Implementation Method 2
when a stage is driven by, e.g. , a planar motor
Implementation Method 3
using a planar motor for movement in six degrees of freedom, and a voice coil motor for precise positioning
Data Source
Figure 1
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AI summary
A supporting member (25) on which a wafer table (WTB) is mounted is substantially kinematically supported, via six rod members (231 to 233, 241 to 243) placed on a slider (22). Further, coupling members (29) are placed facing in a noncontact manner via a predetermined gap, thin plate-shaped edges (25c) provided at both ends in the Y-axis direction of the supporting member (25). By this arrangement, vibrationdamping is performed by the coupling members (29) (squeeze dampers) facing the edges (25c), on vibration of the supporting member (25) mounted on the wafer table (WTB). Further, because the supporting member (25) is kinematically supported via the plurality of rod members, it becomes possible to reduce deformation of the wafer table (WTB) that accompanies deformation of the slider (22).