Deformable Object Table for Non-Flat Substrate Loading
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Solution Overview
Problem
In lithographic processes, substrates with non-flat surfaces experience deformation when clamped onto object tables, leading to patterning accuracy issues and wear, due to friction-induced deformation and relative motion during loading.
Innovation Solution
An object table with a deformable main body and actuator assembly that generates an out-of-plane deformation of the holding surface based on the substrate's shape, allowing conformal loading and minimizing sliding motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate is clamped onto a flat object table, then the substrate can be held in place, but the substrate experiences deformation due to friction and relative motion during loading
Solution Approach 1:
The object table transitions from a static flat surface to a dynamic deformable surface that can adapt its shape. The actuator assembly enables the holding surface to change its configuration in real-time, allowing it to conform to the substrate's bottom surface geometry, thereby eliminating friction-induced deformation during loading
Solution Approach 2:
The physical state of the holding surface is changed from rigid and flat to deformable and adaptive. By controlling the actuator assembly, the holding surface can modify its shape parameters to match the substrate's geometry, transforming the interaction from friction-based clamping to conformal contact
2Reliability
If a substrate with non-flat bottom surface is clamped onto a flat object table, then the substrate can be held, but wear occurs on the object table and friction-induced deformation occurs on the substrate
Solution Approach 1:
The holding surface's geometric parameters are made variable through the actuator assembly, enabling it to adapt to different substrate geometries. This conformal contact eliminates sliding friction during loading, preventing wear on the object table and extending its operational lifespan
Solution Approach 2:
The substrate's non-flat bottom surface, which previously caused friction and wear, is now accommodated by the deformable holding surface. The actuator assembly transforms the geometric mismatch into a conformal contact scenario, converting potential harm into beneficial friction-free loading
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 solution prevents substrate deformation and wear by ensuring precise alignment and contact, enhancing patterning accuracy and extending the object table's lifespan.
Implementation Method 1
The actuator assembly comprises a piezoelectric layer and a plurality of electrodes, the electrodes being configured to, when connected to a power supply, generate an electric field in the piezoelectric layer, the electric field causing a deformation of the piezoelectric layer
Data Source
AI summary
An object table configured to hold an object on a holding surface, the object table including: a main body; a plurality of burls extending from the main body, end surfaces of the burls defining the holding surface; an actuator assembly; and a further actuator assembly, wherein the actuator assembly is configured to deform the main body to generate a long stroke out-of-plane deformation of the holding surface based on shape information of the object that is to be held and the further actuator assembly is configured to generate a short stroke out-of-plane deformation of the holding surface.