EUV Lithography Shadowing Effect Modeling
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Solution Overview
Problem
Current EUV lithography technologies face inaccuracies and inefficiencies in modeling and compensating the shadowing effect due to oblique illumination, leading to CD errors and increased time-to-market for integrated circuits, particularly in handling asymmetric shadowing effects and two-dimensional features.
Innovation Solution
A process model incorporating an EUV lithography shadowing effect component that biases polygon segments based on location information, using expressions like B=Bmax·cosnα to calculate bias, and includes near and far side subcomponents to accurately model and correct shadowing effects, suitable for simulation-model-based correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional process models are used for EUV lithography shadowing effect modeling, then computational speed may be maintained, but modeling accuracy and ability to handle asymmetric shadowing effects deteriorate
Solution Approach 1:
The patent divides the shadowing effect modeling into distinct near-side and far-side components, each handling specific geometric configurations. This segmentation allows the complex asymmetric shadowing effect to be broken down into manageable parts that can be computed separately and combined, improving accuracy without requiring a completely new complex model framework.
Solution Approach 2:
The patent applies different modeling approaches and parameters for near-side and far-side shadowing effects based on their distinct characteristics. By tailoring the model behavior to local geometric conditions (whether a feature is on the near side or far side of the illumination angle), the model achieves higher local accuracy for asymmetric effects while maintaining overall computational efficiency.
2Manufacturing precision
If accurate shadowing effect compensation is implemented, then CD error reduction is achieved, but computational time and processing complexity increase
Solution Approach 1:
The patent pre-calculates and stores shadowing effect parameters and characteristics during the model setup phase. By preparing lookup tables and pre-computing geometric relationships beforehand, the actual shadowing compensation during layout processing can proceed more quickly, reducing computational time while maintaining accuracy.
Solution Approach 2:
The patent uses parameterized expressions with fitted coefficients to represent shadowing effects. By changing from complex geometric computations to parameter-based calculations with pre-determined coefficients, the model achieves accurate CD prediction while significantly reducing computational time during actual processing.
3Productivity
If simple shadowing models are used, then computational efficiency is maintained, but ability to correct asymmetric shadowing effects and handle two-dimensional features deteriorates
Solution Approach 1:
The patent creates a unified shadowing effect model that can handle multiple feature types (lines, spaces, two-dimensional features) and both near-side and far-side asymmetric effects through a single set of expressions and procedures. This universal model maintains computational efficiency while being adaptable to various asymmetric scenarios, eliminating the need for separate specialized models.
Data Source
AI summary
Systems and techniques for modeling the EUV lithography shadowing effect are described. Some embodiments described herein provide a process model that includes an EUV lithography shadowing effect component. Polygon edges in a layout can be dissected into a set of segments. Next, the EUV lithography shadowing effect component can be used to bias each segment. The modified layout having the biased segments can then be used as input for other components in the process model.