Multi-beam Writer Distortion Correction via Sub-region Segmentation
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Solution Overview
Problem
Charged-particle lithography systems face challenges in accurately exposing patterns on substrates due to spatially dependent distortions in the target area, which can lead to errors in pattern fidelity and miniaturization, especially when dealing with non-ideal substrate conditions and distortions that vary across the exposure area.
Innovation Solution
The method involves subdividing the exposure area into non-overlapping sub-regions, determining sub-region dislocations to compensate for distortions, modifying the graphical representation of the pattern by displacing graphical elements according to these dislocations, and calculating an exposure pattern to achieve a nominal dose distribution that corrects for distortions, thereby ensuring accurate contour line representation of the desired pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the exposure area is treated as a single uniform region, then the processing is simpler and faster, but distortion correction precision deteriorates due to spatially varying distortions across the substrate
Solution Approach 1:
The exposure area is divided into multiple non-overlapping sub-regions, with each sub-region having its own distortion correction parameters. This segmentation allows localized correction of spatially varying distortions while maintaining manageable computational complexity for each individual sub-region.
Solution Approach 2:
Each sub-region is assigned specific distortion correction characteristics (scaling, rotation, displacement parameters) that are optimized for its local distortion profile. This local quality approach ensures that correction parameters are tailored to the specific spatial location, improving overall pattern fidelity without requiring a uniformly complex correction system across the entire exposure area.
2Manufacturing precision
If the exposure area is divided into many small sub-regions, then distortion correction precision improves, but computational complexity and processing time increase
Solution Approach 1:
The exposure area is segmented into a moderate number of non-overlapping sub-regions that balance correction precision with computational efficiency. Each sub-region is small enough to have relatively uniform distortion characteristics, yet large enough to avoid excessive segmentation that would increase processing time.
Solution Approach 2:
The method applies distortion correction to all sub-regions uniformly, ensuring that even areas with minor distortions receive appropriate correction. This partial correction approach (correcting only the necessary parameters for each sub-region rather than all possible parameters) maintains precision while controlling computational overhead.
3Manufacturing precision
If distortion correction parameters are applied to each sub-region, then pattern fidelity improves, but the complexity of calculating and applying corrections increases
Solution Approach 1:
Each sub-region is assigned a specific set of distortion correction parameters (scaling factors, rotation angles, displacement values) that are calculated based on local distortion measurements or models. This localized parameter assignment improves contour line accuracy while keeping the calculation complexity manageable by limiting the number of parameters per sub-region.
Solution Approach 2:
The method transforms the distortion correction problem into a parameter optimization problem, where correction parameters for each sub-region are determined to minimize pattern fidelity errors. By changing the approach from complex spatial transformations to parameter-based corrections, the system achieves high accuracy with reduced computational complexity.
Data Source
AI summary
Method for computing an exposure pattern for exposing a desired pattern on a target in a charged-particle lithography apparatus, in which a particle beam is directed to and illuminates a pattern definition device comprising an aperture array composed of a plurality of blanking apertures through which said particle beam penetrates for writing said desired pattern by exposing a multitude of pixels within an exposure area on the target, said method taking into account a spatially dependent distortion of the target within the exposure area, with respect to dislocations transversal to the direction of the particle beam.