Variable-Width Stage Locking for Reticle Exchange Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithographic apparatuses face challenges in reticle exchange processes due to unknown reticle position offsets and tilt, leading to particle generation and damage to reticles and clamps, which are not effectively addressed by conventional locking devices.
Innovation Solution
A locking device with a variable-width ring feature and actuator is used to engage a slot, adjusting the width to prevent relative motion between movable stages, ensuring precise alignment and reducing damage during reticle exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locking devices are used during reticle exchange, then the structure is simple, but relative motion between clamp and reticle occurs causing particle generation and damage
Solution Approach 1:
The locking device employs a dynamic wheel device with variable-width ring features that rotate to engage with slots in the movable stage. The width of the ring feature changes as it rotates, allowing smooth engagement and locking without rigid constraints, thereby preventing relative motion while maintaining simplicity
Solution Approach 2:
The ring feature's width parameter varies with rotation angle, enabling the locking mechanism to adapt to position offsets and tilt. This parameter change allows the locking device to maintain reliable engagement across different alignment conditions without requiring complex adjustment mechanisms
2Adaptability or versatility
If fixed-width ring feature is used in locking device, then manufacturing is simple, but it cannot accommodate unknown reticle position offset and tilt
Solution Approach 1:
The ring feature's width is made dynamic through rotation rather than complex variable geometry. The same circular cross-section rotates to different angles, effectively changing the width parameter to accommodate position offsets and tilt, while maintaining manufacturing simplicity
Solution Approach 2:
The wheel device utilizes a circular cross-section with constant curvature, where the ring feature's effective width varies due to rotation angle. This curved geometry allows the locking device to adapt to unknown reticle position offsets and tilt without requiring complex variable-width manufacturing processes
3Productivity
If conventional locking mechanisms are used, then device complexity is low, but reticle exchange throughput is reduced due to alignment issues
Solution Approach 1:
The locking device is designed to accommodate unknown position offsets and tilt in advance through the rotational engagement mechanism. The variable-width ring feature automatically adjusts to align with the slot during rotation, enabling faster reticle exchange without requiring complex pre-alignment procedures
Data Source
AI summary
A lithographic apparatus includes an illumination system to illuminate a pattern of a patterning device, a projection system to project an image of the pattern onto a substrate, a movable stage to support the patterning device or the substrate, a slotted object, and a locking device (700) to prevent a motion of the movable stage. The locking device comprises an actuator (702) and a wheel device (704) comprising a ring feature (708) and coupled to the actuator. The actuator rotates the wheel device about a rotation axis (706). The ring feature has a width (710) defined parallel to the rotation axis. The width is variable with respect to azimuthal direction of the wheel device. The ring feature engages a slot of the slotted object. The rotating adjusts the width of the ring feature within the slot such that a relative motion between the device and the slotted object is prevented.