Reticle Stage Dynamic Bending for Lithography Distortion
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Solution Overview
Problem
Current lithography tools face challenges with reticle and optics distortion due to heat and non-flat reticle surfaces, leading to printing and overlay errors, and existing solutions are either overly complex or prone to reticle slippage during high-acceleration scanning.
Innovation Solution
A reticle stage design that applies a deterministic bending moment to the reticle using opposing chuck bodies and compliant blade-chucks within a vacuum seal to correct distortion while maintaining a high grip and preventing slippage, even at high accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a support clamp and actuators are provided on the reticle stage to bend the reticle, then reticle distortion is compensated, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the bending function from a separate support clamp and actuators system, and integrates it into the reticle chuck itself. The reticle chuck is designed with movable segments that can independently displace to create bending moments, eliminating the need for separate bending actuators and simplifying the overall device structure while maintaining distortion compensation capability.
Solution Approach 2:
The reticle chuck is designed to perform multiple functions: it both chucks the reticle securely and provides the bending moment for distortion compensation. By making the chuck segments movable, a single component achieves both retention and shape control functions, reducing device complexity.
2Manufacturing precision
If vacuum pressure is reduced to induce reticle bending, then distortion correction is achieved, but reticle grip is reduced causing slippage during high-acceleration scanning
Solution Approach 1:
The reticle chuck is divided into multiple independently movable segments. These segments can be displaced differentially to create bending moments in the reticle while maintaining vacuum grip through the segment edges. The segmentation allows independent control of grip and bending functions.
Solution Approach 2:
Different regions of the reticle chuck serve different functions: the edges of the chuck segments maintain vacuum grip on the reticle, while the movable displacement of segments creates localized bending moments. This local differentiation allows simultaneous achievement of secure grip and distortion compensation.
3Manufacturing precision
If opposing forces are applied to bend the reticle, then distortion is compensated, but the force application mechanism becomes overly complicated
Solution Approach 1:
The patent eliminates the complex external actuator system by extracting the bending function directly into the reticle chuck structure. The movable segments of the chuck itself generate the bending moments through their displacement, removing the need for separate force application mechanisms.
Solution Approach 2:
The reticle chuck serves itself by using its own movable segments to generate the bending moments required for distortion compensation. The system uses its inherent structure to provide the corrective action, eliminating the need for external service mechanisms.
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
The solution effectively compensates for optical distortion and prevents reticle slippage during scanning and acceleration, ensuring accurate patterning and reducing overlay errors in lithography tools.
Implementation Method 1
The reticle stage provides reticle bending to compensate for optical distortion by applying a bending moment to the reticle. The bending moment is generated by applying a force, along a plane surface of the reticle, to bend the reticle in a deterministic manner.
Implementation Method 2
By controlling the negative pressure within the vacuum seal, a grip sufficient to prevent slippage, even at high-accelerations, is achieved.
Data Source
AI summary
A scanning lithography tool that includes a reticle stage for clamping and imparting a bending moment onto a reticle by applying a force along a plane surface of the reticle to bend the reticle in a deterministic manner.