Electron-beam exposure proximity effect correction
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Solution Overview
Problem
Conventional electron-beam exposure systems face challenges in efficiently correcting the proximity effect, leading to inaccurate pattern formation due to electron scattering, and existing methods are computationally intensive, hindering processing rate and precision.
Innovation Solution
An electron-beam exposure system utilizing a density-per-area map generating mechanism and proximity-effect correcting means, which performs product-sum arithmetic and addition on two-dimensional array data using a graphic processor to calculate exposure corrections, thereby overcoming the limitations of CPU-based methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CPU-based methods are used for proximity-effect correction calculations, then computational precision can be maintained, but processing rate decreases due to computational intensity
Solution Approach 1:
The patent replaces the CPU-based sequential computational system with a GPU-based parallel processing system. The GPU's architecture with multiple cores enables simultaneous execution of calculation tasks, substituting the traditional mechanical computation approach with a parallelized electronic processing approach that achieves both high precision and high speed correction of proximity effects
Solution Approach 2:
The patent divides the computational task into multiple segments that can be processed in parallel. By segmenting the exposure area into multiple regions and assigning different calculation tasks to different GPU cores, the system maintains computational precision while significantly increasing the overall processing rate through concurrent execution of multiple calculation segments
2Manufacturing precision
If conventional correction methods are applied, then pattern formation accuracy is compromised due to electron scattering effects, but computational complexity remains manageable
Solution Approach 1:
The patent performs preliminary calculations of the proximity effect correction amounts before actual exposure. By pre-calculating the correction values using GPU-based parallel processing and storing them in a correction map, the system eliminates the need for complex real-time calculations during exposure, thereby improving pattern formation accuracy while managing computational complexity through advance preparation
Solution Approach 2:
The patent introduces a correction map as an intermediary data structure that stores pre-calculated proximity effect correction values. This intermediary allows the system to separate the complex calculation phase from the exposure phase, enabling accurate correction without requiring complex computational operations during the actual exposure process
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
This approach enables precise and high-rate correction of the proximity effect, ensuring accurate pattern formation by leveraging parallel processing and reducing computational complexity, resulting in faster and more efficient exposure calculations.
Implementation Method 1
a phenomenon in which the line width and the like of a pattern transferred onto a resist is different from its design value stems from influence of what is termed as the proximity effect, in which incident electrons are scattered in the resist
Implementation Method 2
the widths of the patterns become larger than the design values in the middle portions respectively of the patterns which face each other. This is because the back scattering of the electron beam from every part of each pattern is greatly influential
Data Source
AI summary
An electron-beam exposure system includes: density-per-area map generating means configured to divide a certain area on which an electron beam is irradiated into meshes, to figure out a ratio of an area of patterns to be irradiated on each divided region to an area of the divided region, thus to generate a density-per-area map; and proximity-effect correcting means configured to correct exposure of the electron beam by referring to the density-per-area map. The proximity-effect correcting means includes: product-sum arithmetic means which is configured to perform product-sum arithmetic on two-dimensional array data, and addition means which is configured to perform addition arithmetic on the two-dimensional array data; stores, in a first memory, two-dimensional array data on the density per area of the patterns; performs the product-sum arithmetic and the addition a predetermined number of times, and thus calculates the two-dimensional array data on the density per area by a linear conversion; and uses the resultant data as two-dimensional array data on exposure to be used for correcting a proximity effect.