Lithographic Sub-Field Control for Overlay Precision and Image Contrast
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Solution Overview
Problem
Existing lithographic processes face challenges in accurately controlling overlay errors and maintaining high contrast during pattern transfer due to limitations in actuator capabilities and dynamic stage position errors, leading to inefficiencies and reduced yield in semiconductor manufacturing.
Innovation Solution
Implementing a method for co-determining stage and lens manipulator control profiles to minimize error and ensure minimum contrast quality, utilizing a deformable reflector to adjust the wavefront of the radiation beam and correct spatial variations in the exposure field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dynamic stage control is used to correct overlay errors, then overlay precision is improved, but image contrast deteriorates due to stage position errors during exposure
Solution Approach 1:
The exposure field is divided into multiple sub-fields, each with its own control profile. This allows independent optimization of overlay correction and contrast maintenance for different regions, resolving the contradiction by applying localized control strategies rather than global control that would compromise overall contrast
Solution Approach 2:
Different control profiles are applied to different sub-fields based on their specific requirements. The stage control and lens manipulator control are optimized locally for each sub-field, enabling precise overlay correction in critical areas while maintaining contrast in other regions
2Manufacturing precision
If stage control profile is optimized to minimize overlay error, then overlay accuracy is improved, but contrast quality deteriorates due to dynamic stage position errors
Solution Approach 1:
Control profiles are determined in advance before the lithographic process begins. The co-determination of stage and lens manipulator control profiles预先 optimizes the control strategy, allowing the system to follow predetermined trajectories that balance overlay accuracy and contrast quality without real-time trade-offs
Solution Approach 2:
The control profiles are determined based on measured spatial profiles of performance parameters. This feedback loop allows the system to adjust control strategies based on actual system behavior, optimizing both overlay accuracy and contrast quality through data-driven control profile generation
3Manufacturing precision
If co-determined control profiles are applied to correct spatial variations, then manufacturing precision is improved, but device complexity increases due to multiple control systems
Solution Approach 1:
The stage control and lens manipulator control are co-determined and coordinated as an integrated control system. By merging the control of multiple actuators under a unified control profile generation process, the system achieves complex spatial corrections through coordinated simple actions rather than independently complex control 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
Enhances the ability to correct overlay errors and maintain image contrast, improving the accuracy and yield of semiconductor manufacturing processes by allowing precise control at a sub-field level.
Implementation Method 1
utilizing a deformable reflector to adjust the wavefront of the radiation beam and correct spatial variations in the exposure field
Data Source
AI summary
A method for determining a correction for control of a lithographic process for exposing a pattern on an exposure field using a lithographic apparatus. The method including obtaining a spatial profile describing spatial variation of a performance parameter across at least a portion of the exposure field and co-determining control profiles for the spatial profile to minimize error in the performance parameter while ensuring a minimum contrast quality. The co-determined control profiles include at least a stage control profile for control of a stage arrangement of the lithographic apparatus and an optical element (e.g., lens) manipulator control profile for control of an optical element manipulator of the lithographic apparatus, the manipulator operable to perform a correction for at least magnification in a direction perpendicular to the substrate plane.