Aperture Array Correction Using Block-Based Beam Shift Compensation
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Solution Overview
Problem
In multibeam writing processes for semiconductor devices, beam shifts and current density deviations lead to pattern inaccuracies and increased writing time due to mismatched estimated and actual error distributions in aperture arrays, complicating the design modifications required for correction.
Innovation Solution
A method for calculating aperture correction amounts by measuring shift and current density distributions, dividing the beam array into blocks, and applying uniform corrections within each block to align and adjust the aperture positions and dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aperture correction is applied based on estimated error distributions, then beam alignment accuracy is improved, but the complexity of design modifications increases
Solution Approach 1:
The patent divides the aperture array into multiple blocks and applies uniform correction amounts within each block. This segmentation approach simplifies the design modification process by reducing the number of unique correction values that must be implemented, while still achieving improved beam alignment accuracy across the entire array.
Solution Approach 2:
The patent applies different uniform correction amounts to different block regions based on the measured shift amount distribution. This local quality approach allows the system to address spatial variations in beam alignment errors without requiring unique corrections for every individual aperture, thereby balancing precision with design simplicity.
2Manufacturing precision
If beam shifts and current density deviations are corrected individually, then pattern precision is improved, but writing time increases
Solution Approach 1:
The patent groups apertures into blocks and applies uniform correction amounts within each block rather than individual corrections. This segmentation reduces the computational complexity and data processing requirements, enabling faster writing operations while maintaining improved pattern precision through block-level correction.
Solution Approach 2:
The patent changes the correction parameter from individual aperture-level adjustments to block-level uniform corrections. This parameter change reduces the dimensionality of the correction problem, allowing for more efficient processing and shorter writing times while still achieving acceptable pattern precision through the measured and applied correction amounts.
3Device complexity
If uniform correction amounts are applied within block regions, then design complexity is reduced, but correction precision for individual beams may be compromised
Solution Approach 1:
The patent applies different uniform correction amounts to different block regions based on the measured shift amount distribution. This ensures that each block receives the appropriate correction for its local error characteristics, maintaining good individual beam correction precision while simplifying the overall design by using uniform corrections within blocks rather than unique corrections for every aperture.
Data Source
AI summary
In one embodiment, an aperture correction amount calculation method is for calculating a correction amount for positions or dimensions of a plurality of apertures formed in an aperture array substrate through which multiple charged particle beams pass. The method includes measuring a shift amount distribution on an irradiation surface, which is a distribution of shift amounts from a predetermined position or a predetermined current density of each beam within a beam array of the multiple charged particle beams, dividing the beam array into a predetermined number of block regions based on the shift amount distribution, and calculating a representative value of the shift amounts corresponding to each block region, and calculating, for each of the block regions, correction amounts for positions or dimensions of the corresponding apertures of the aperture array substrate based on the representative values.