Actuator Particle Shield Structure for Cleaner Z-Axis Stages
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Solution Overview
Problem
Semiconductor and similar industries face particle contamination issues due to the movement of components in metrology and fabrication equipment, which generates particles that can settle on substrates during complex motion requirements, including Cartesian, Polar, and Z-axis movements.
Innovation Solution
A particle shield for actuator housings with a ring and plate configuration that extends along the Z-axis, maintaining coaxial alignment without contact, reduces the cross-sectional area for particle escape and enhances pressure differential for improved evacuation, allowing for multiple degrees of freedom while minimizing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a particle shield is introduced to reduce particle contamination, then substrate cleanliness is improved, but device complexity increases due to the additional ring and plate components
Solution Approach 1:
The particle shield utilizes a nested structure where the ring is mounted on the actuator housing and the plate is mounted on the Z-axis stage, with the plate positioned inside the ring's collar. This nested arrangement creates an enclosed space that traps particles generated by actuator components, preventing them from contaminating the substrate while integrating the shield within the existing multi-degree-of-freedom stage structure.
Solution Approach 2:
The particle shield is segmented into two separate components: a stationary ring mounted on the actuator housing and a moving plate mounted on the Z-axis stage. This segmentation allows each component to perform its specific function independently while working together to contain particles, reducing the complexity compared to a single monolithic shield structure.
2Object-affected harmful factors
If the collar and plate are positioned close to each other to minimize particle escape routes, then particle containment is improved, but the risk of contact during rotation and movement increases
Solution Approach 1:
The particle shield design accounts for dynamic motion by allowing the plate to rotate and move vertically within the ring's collar without making contact. The collar's internal diameter is slightly larger than the plate's external diameter, creating a small clearance that accommodates rotational and vertical movements while maintaining effective particle containment. This dynamic clearance prevents contact while minimizing particle escape routes.
3Object-affected harmful factors
If the particle shield structure is made more complex to enhance particle evacuation, then particle removal efficiency is improved, but manufacturing difficulty increases
Solution Approach 1:
The particle shield design extracts and isolates particles generated by the actuator components into a contained space between the ring and plate. By positioning the shield components to enclose the particle-generating areas, particles are naturally trapped and removed with the exhaust air flow, enhancing particle evacuation without requiring complex active removal mechanisms.
Data Source
AI summary
A particle shield for an actuator housing in a semiconductor equipment system includes a ring that mounts to the actuator housing, and a plate that mounts to a Z-axis stage that moves relative to the actuator housing. The ring includes a collar that extends from a flange in the Z coordinate direction. The collar and the plate, or a skirt that extends from the outside perimeter of the plate in the Z coordinate direction, remain within a same plane and do not contact each other during movement in the Z coordinate direction by the first Z-axis stage. The plate and the collar may be coaxial so that plate and the collar do not contact each other during rotation of the Z-axis stage relative to the actuator housing. A second Z-axis stage to which a chuck may be mounted passes through an aperture in the plate.