Substrate Shape Measuring Device for Warped Substrate Handling
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Solution Overview
Problem
Current substrate handling devices are limited in handling substrates with warpage beyond the maximum limit of half a millimeter, leading to performance decreases and clampability issues due to increased local gaps and stiffness, which prevents effective suction pressure and accurate positioning.
Innovation Solution
A substrate shape measuring device with sensor assemblies that emit and receive light to measure substrate dimensions, allowing for the determination of substrate shape and warpage, enabling adaptive handling processes such as vacuum clamping and loading adjustments based on the measured shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate handling devices use traditional clamping methods, then substrates with flat surfaces can be handled effectively, but substrates with warpage beyond half a millimeter cannot be properly clamped due to increased local gaps and substrate stiffness
Solution Approach 1:
The substrate table is designed with movable components including loading pins that can adjust their positions and a vacuum distribution system that can dynamically redistribute suction pressure. This dynamic adaptability allows the handling device to accommodate substrates with warpage up to one millimeter by adjusting the clamping force distribution across the substrate surface, preventing both over-clamping of flat regions and under-clamping of warped regions.
Solution Approach 2:
The system changes the vacuum pressure parameters dynamically during substrate handling. By monitoring substrate position and warpage characteristics, the vacuum distribution system adjusts the suction pressure levels across different zones of the substrate table, optimizing clamping effectiveness for substrates with varying degrees of warpage while maintaining reliable handling.
2Manufacturing precision
If substrate handling devices are designed for flat substrates, then positioning accuracy is maintained, but handling of warped substrates results in performance decrease and positioning errors
Solution Approach 1:
The system performs preliminary measurement of substrate warpage characteristics before the actual handling operation. This preliminary action allows the control system to pre-calculate compensation values and adjust the positioning parameters in advance, ensuring that subsequent positioning operations account for the substrate's actual shape and achieve accurate placement despite warpage.
Solution Approach 2:
The substrate table incorporates sensors that provide real-time feedback on substrate position, orientation, and contact points during handling. This feedback loop allows the control system to continuously adjust positioning commands and vacuum distribution to compensate for warpage effects, maintaining positioning accuracy for substrates with up to one millimeter warpage.
3Force
If maximum vacuum pressure is applied to clamp substrates, then clamping force is sufficient for flat substrates, but warped substrates cannot achieve adequate vacuum levels due to larger local gaps
Solution Approach 1:
The vacuum distribution system is divided into multiple zones with independently controllable vacuum levels. This local quality approach allows different regions of the substrate table to operate at optimized vacuum pressures, applying higher force where the substrate contacts the table and maintaining adequate force across warped regions without requiring uniform maximum pressure across the entire surface.
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
Enables reliable and predictable handling of substrates with warpage beyond the traditional limit by providing accurate shape data for improved clamping, positioning, and transfer processes, enhancing overlay and focus performance in lithographic processes.
Implementation Method 1
one or more sensor assemblies, each comprising a light emitter to emit light in a direction substantially parallel to the first plane and a light sensor arranged to receive the light, wherein each of the one or more sensor assemblies is arranged to provide a light measurement signal representative for a dimension of the substrate in a direction perpendicular to the first plane
Data Source
AI summary
A substrate shape measuring device, including: a substrate support to support a substrate having a main surface, the main surface of the substrate when supported by the substrate support substantially extending in a first plane; one or more sensor assemblies, each including a light emitter to emit light along a light axis substantially parallel to the first plane and a light sensor arranged to receive the light; and a processing device arranged to determine a shape of the substrate, wherein the substrate shape measuring device is constructed to measure with the one or more sensor assemblies in at least a first measurement direction with respect to the substrate substantially parallel to the first plane and a second measurement direction with respect to the substrate substantially parallel to the first plane.