3D Mask Corner Rounding Simulation Using Feature Images

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Solution Overview

Problem

Existing lithography simulations struggle with accurately modeling mask corner rounding effects due to limitations in mask making processes, leading to inefficient and computationally intensive simulations, especially for complex shapes with arbitrary edge angles and small jogs, which increase runtime and reduce accuracy.

Innovation Solution

The approach involves partitioning the layout geometry into feature images, applying mask corner rounding (MCR) corrections to these images, and using precomputed M3D filters to calculate the mask function, reducing the need for additional layout vertices and improving simulation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional three-dimensional mask models are used to accurately model mask corner rounding effects, then manufacturing precision is improved, but computational time increases significantly

Engineering Contradiction:
Improvemask corner rounding accuracyVSAvoidsimulation runtime
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent segments the mask layout into discrete feature images representing different corner rounding scenarios. Each feature image is pre-processed and stored in a library, allowing the simulation to quickly retrieve and combine relevant features rather than computing three-dimensional models from scratch for each corner rounding case. This segmentation enables accurate modeling of mask corner rounding effects while significantly reducing computational runtime.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If complex shapes with arbitrary edge angles and small jogs are simulated using traditional methods, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvelayout geometry accuracyVSAvoidsimulation model complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent decomposes complex shapes with arbitrary edge angles and small jogs into simpler feature images that can be retrieved from a pre-computed library. Instead of using a single complex three-dimensional model for the entire shape, the method segments the geometry into manageable feature components (such as corner features, edge features, and junction features) that are processed independently and then combined. This reduces simulation model complexity while maintaining manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different levels of modeling detail to different parts of the layout geometry based on their specific characteristics. Simple regions use basic feature images, while complex regions with arbitrary edge angles or small jogs use more detailed feature combinations. This local quality approach allows the simulation to maintain high manufacturing precision where needed without unnecessarily increasing device complexity across the entire layout.

Inventive Principle:
Principle #3Local quality

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 method enhances computational efficiency and accuracy in lithography simulations by reducing runtime and maintaining precision, making it suitable for both machine learning frameworks and graphics processing units, while providing accurate results for Hopkins and Abbe imaging models.

Implementation Method 1

The feature images have corresponding mask 3D (M3D) filters, which represent the electromagnetic scattering effect of that feature image for a given source illumination

Methodology Applied
Scientific EffectElectromagnetic scattering: Scattering

Data Source

PatentUS12481213B2Mask corner rounding effects in three-dimensional mask simulations using feature images
Publication Date: 2025.11.25 SYNOPSYS INC
  • US12481213B2 patent drawing
  • US12481213B2 patent drawing
  • US12481213B2 patent drawing

AI summary

A layout geometry of a lithographic mask is received. The layout geometry includes at least one shape having one or more rounded corners. The layout geometry is partitioned into a plurality of feature images, for example as selected from a library. The feature images include at least one mask corner rounding (MCR)-corrected feature image that accounts for the rounded corners of the shape. The feature images have corresponding mask 3D (M3D) filters, which represent the electromagnetic scattering effect of that feature image for a given source illumination. The mask function contribution from each of the feature images is calculated by convolving the feature image with its corresponding M3D filter. The mask function contributions are combined to determine a mask function for the mask illuminated by the source illumination.