Shape-Based Proximity Correction for Particle Beam Lithography
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Solution Overview
Problem
Existing shape correction methods for particle beam lithography face limitations in improving both pattern fidelity and image contrast, particularly when dealing with severe resist contour distortions and edge-placement errors, while also requiring significant computational effort.
Innovation Solution
A shape-based proximity effect correction method that utilizes a bottom and top layer structure with optimized width and space relationships, combined with a PID feedback controller, to enhance throughput, fidelity, and contrast in particle beam lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a larger particle beam size is adopted to decrease beam-exposure time and increase production yield, then throughput is improved, but the gentle slope of the accumulated dose distribution leads to degradation of pattern fidelity and image contrast
Solution Approach 1:
The patent divides the pattern into multiple segments and applies different doses to each segment based on its local environment. This segmentation allows the system to use a larger beam size for efficiency while still achieving precise control over the accumulated dose distribution, thereby maintaining pattern fidelity despite the gentler slope caused by larger beam size.
Solution Approach 2:
The patent implements local quality by assigning different dose values to different regions of the pattern based on their specific characteristics. The dose-shape hybrid correction method calculates optimal doses for each segment considering local proximity effects, enabling the system to maintain high pattern fidelity across the entire pattern even when using a larger beam size that would otherwise produce uniform gentle slopes.
2Loss of time
If a larger particle beam size is adopted to decrease beam-exposure time, then exposure time is reduced, but image contrast is degraded due to gentle slope of accumulated dose distribution
Solution Approach 1:
The patent changes the dose parameter locally across different pattern segments to compensate for the gentler dose distribution slope caused by larger beam size. By adjusting the dose parameter in the dose-shape hybrid correction method, the system maintains adequate image contrast while benefiting from the reduced exposure time enabled by the larger beam size.
3Manufacturing precision
If dose correction method is used to determine proper dose for each beam-shot position, then pattern fidelity is improved, but computation time increases because each dose needs to be calculated individually
Solution Approach 1:
The patent applies partial dose correction by combining shape correction (which provides a baseline correction) with selective dose adjustments for specific segments. This partial approach achieves sufficient pattern fidelity without requiring the full computational effort of calculating individual doses for every beam-shot position, thereby reducing computation time while maintaining acceptable precision.
Solution Approach 2:
The patent performs preliminary shape correction to establish a corrected pattern geometry before applying dose adjustments. This preliminary action reduces the complexity of subsequent dose calculations by pre-accounting for some proximity effects through shape modification, thereby reducing the computational burden while maintaining pattern fidelity.
4Device complexity
If shape correction method with single-dose is used to modify pattern shape, then computation amount is reduced and compatibility is improved, but correction effectiveness is limited under severe resist contour distortions
Solution Approach 1:
The patent merges shape correction and dose correction into a hybrid approach. The shape correction component provides computational efficiency and compatibility benefits, while the dose correction component adds the necessary effectiveness for severe distortion cases. This combination achieves both low computational complexity and high correction effectiveness by leveraging the strengths of both methods.
Solution Approach 2:
The patent creates a composite correction method that combines elements of shape correction and dose correction. Like composite materials that combine different properties to achieve superior performance, this composite approach integrates the computational efficiency of shape correction with the correction power of dose adjustment, achieving effective correction even under severe resist contour distortions.
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 method achieves improved pattern fidelity and contrast by reducing edge-placement errors and computational effort, with a 95% average slope improvement and 53% reduction in calculation time compared to conventional methods.
Implementation Method 1
exposure to a particle beam, thereby producing an imaging pattern
Data Source
AI summary
Disclosed herein is a proximity effect correction method based on shape adjustment for fabricating an imaging structure. The imaging structure comprises a bottom layer arranged on a substrate, and a top layer arranged on the upper surface of the bottom layer. The position of a surrounding frame of the top layer is closed to an edge of the bottom layer, which has a width value and a space value between the top and bottom layers. Additionally, the method combines with the use of increased particle beam sizes to improve the throughput, imaging fidelity and contrast of a particle beam lithography system. The method is applicable to any particle beam lithography machine or system, and does not require any internal hardware and software modifications to the machine or system.