Substrate Support Actuator Compensation Unflatness
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Solution Overview
Problem
Conventional lithographic apparatuses face challenges in compensating higher-order unflatness of substrate surfaces, particularly at the edge areas, due to substrate deformation or unflat support surfaces, which cannot be adequately addressed by traditional leveling methods.
Innovation Solution
A substrate support with integrated actuators that can contract or extend in a direction parallel to the support surface, allowing for localized bending to compensate for unflatness, using piezo actuators aligned with the support surface to create a curve that aligns the substrate edge with the patterned beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional leveling methods are used to compensate substrate unflatness, then first-order unflatness within the target portion can be compensated, but higher-order unflatness particularly in the edge area cannot be adequately addressed
Solution Approach 1:
The substrate support surface is segmented into multiple independent burls arranged in concentric circles, allowing each burl to be independently adjusted. This segmentation enables localized compensation of higher-order unflatness in different areas of the substrate, particularly in the edge regions that traditional leveling cannot address.
Solution Approach 2:
The burls are made dynamically adjustable through integration of actuators (such as piezoelectric actuators) that can change the height and position of each burl in real-time. This dynamic capability allows the support surface to adapt to and compensate for higher-order unflatness variations across the substrate, going beyond static traditional leveling methods.
2Ease of operation
If outer burls are used to support the edge area of the substrate, then the edge area can be supported, but wear and polishing cause these burls to have lower height, resulting in unflatness of the support surface
Solution Approach 1:
The actuator system enables preliminary adjustment of burl heights before substrate loading. Outer burls that have been worn down can be proactively restored to their original heights, preventing support surface unflatness before it affects substrate positioning or pattern transfer accuracy.
Solution Approach 2:
The system incorporates sensors that continuously monitor the height and position of each burl, providing feedback to the control system. This feedback mechanism detects wear and height variations in outer burls, enabling automatic compensation and restoration of support surface flatness, thereby maintaining manufacturing precision despite ongoing wear.
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
Effectively compensates for higher-order unflatness in the edge areas of substrates, improving pattern transfer accuracy by dynamically adjusting the support surface to match the substrate's curvature, thereby enhancing the precision of the lithographic process.
Implementation Method 1
A substrate support with integrated actuators that can contract or extend in a direction parallel to the support surface, allowing for localized bending to compensate for unflatness, using piezo actuators aligned with the support surface
Data Source
AI summary
The present invention relates to a substrate support (1), comprising:a support body (2) forming a support surface configured to support a substrate, wherein said support surface comprises a support surface part configured to support a substrate area of the substrate,at least one actuator (6) arranged on the support body at a location aligned with the support surface part and configured to contract or extend in a direction substantially parallel to a main plane of the support surface.