Deformable Object Table for Non-Flat Substrate Alignment
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Solution Overview
Problem
In lithographic processes, substrates with non-flat surfaces undergo deformation when clamped onto object tables, leading to patterning accuracy issues and yield loss due to friction-induced deformations and wear, especially during loading and alignment of consecutive patterned layers.
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 shape information of the substrate, allowing conformal loading and minimizing sliding motion to prevent deformation and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate with non-flat surface is clamped onto a flat holding surface, then the substrate can be held in place, but the substrate undergoes unwanted deformation affecting patterning accuracy
Solution Approach 1:
The holding surface is made dynamically deformable through an actuator assembly that can adjust the surface shape in real-time. The actuators bend the holding surface to match the substrate's non-flat geometry, allowing the substrate to be held without deformation. This dynamic adaptation resolves the contradiction between holding stability and patterning accuracy.
Solution Approach 2:
The physical parameter of the holding surface (its shape/curvature) is changed to match the substrate's surface profile. By varying the surface curvature parameters through actuator control, the system adapts to different substrate geometries, preventing deformation while maintaining holding stability and ensuring patterning accuracy.
2Reliability
If a substrate is clamped onto a flat holding surface, then the substrate can be secured, but friction-induced deformation occurs during loading and alignment
Solution Approach 1:
The holding surface dynamically conforms to the substrate shape during the loading process. As the substrate is placed onto the deformable surface, the actuators adjust the surface geometry to match the substrate, minimizing contact friction and preventing friction-induced deformation while still securing the substrate reliably.
Solution Approach 2:
The holding surface preliminarily deforms to match the substrate's expected geometry before the substrate is fully secured. This preliminary conformation reduces friction during the loading and alignment process, preventing deformation while ensuring reliable securing.
3Productivity
If repeated loading and unloading of substrates is performed, then productivity is maintained, but wear of the holding surface increases
Solution Approach 1:
The deformable holding surface adapts to each substrate's specific geometry during loading, distributing contact forces more evenly across the substrate surface. This reduces localized stress concentrations and wear on the holding surface, maintaining both productivity and durability over repeated cycles.
Solution Approach 2:
The surface geometry parameters are dynamically adjusted for each substrate, optimizing the contact distribution pattern. This parameter adaptation minimizes wear during each loading cycle, preserving holding surface durability while maintaining high substrate processing throughput.
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 ensures accurate alignment and patterning by avoiding substrate deformation and wear, enhancing the precision and reliability of the lithographic process while reducing friction-induced issues during loading and processing.
Implementation Method 1
an actuator assembly, wherein the actuator assembly is configured to deform the main body to generate an out-of-plane deformation of the holding surface, based on shape information of the object that is to be held
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.