ML Photolithography Mask Simulation for 3D Effects

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Solution Overview

Problem

Current methods for simulating aerial images of photolithography masks are either time-consuming and inaccurate or require extensive computational resources, failing to effectively account for mask 3D effects and short wavelengths.

Innovation Solution

A computer-implemented method using a machine learning model to simulate the propagation of electromagnetic waves through a detailed model of a photolithography mask, incorporating absorber and mask carrier sections, and applying a simulation of the imaging process to generate an aerial image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rigorous simulation methods (FDTD, RCWA) are used to simulate aerial images, then accuracy is improved, but computation time and computational resources increase significantly

Engineering Contradiction:
Improveaerial image simulation accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent creates a machine learning model that learns from rigorous simulation data and produces aerial image simulations that copy the accuracy of FDTD/RCWA methods but with much faster computation. The ML model is trained on training data generated by rigorous simulation methods, allowing it to replicate their accuracy without requiring the same computational intensity during actual use.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the fundamental approach from direct physical simulation to data-driven prediction. By transforming the simulation problem into a pattern recognition task where the ML model maps mask models to aerial images through learned parameters, it achieves both speed and accuracy without following the computationally intensive physical simulation steps.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If thin element approximation is used for fast aerial image simulation, then computation time is reduced, but accuracy deteriorates due to inability to account for mask 3D effects

Engineering Contradiction:
Improvecomputation timeVSAvoidaerial image simulation accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent changes the input parameters to include comprehensive 3D mask geometry information (absorber section height, mask carrier section thickness, multilayer structure) rather than relying on thin element approximations. This allows the ML model to capture mask 3D effects while maintaining fast computation speeds.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The ML model copies the physical accuracy of rigorous simulation methods by being trained on their output data, while avoiding their computational burden. It learns the complex relationships between 3D mask structures and aerial images without performing the intensive physical calculations required by FDTD or RCWA.

Inventive Principle:
Principle #26Copying

3Measurement precision

If detailed 3D mask models are used to account for mask 3D effects, then accuracy is improved, but device complexity and computational requirements increase

Engineering Contradiction:
Improveaerial image simulation accuracyVSAvoidsimulation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a machine learning model that copies the results of complex rigorous simulations without replicating their complexity. The ML model takes detailed 3D mask models as input but processes them through simplified pattern recognition operations, reducing the computational complexity required to achieve the same accuracy.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical simulation process (solving Maxwell's equations numerically) with an information-processing approach (machine learning pattern recognition). This substitution dramatically reduces computational complexity while maintaining accuracy through data-driven learning of the physical relationships.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 accurate and fast simulation of aerial images, reducing computation time and memory requirements while effectively modeling mask 3D effects and short wavelengths, thereby improving photolithography mask design and defect detection.

Implementation Method 1

simulating the propagation of the incident electromagnetic waves through the model of the photolithography mask using a machine learning model, wherein the machine learning model maps the model of the photolithography mask to a representation of an electromagnetic field generated by the incident electromagnetic waves

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

the grating comprising absorber structures and non-absorber structures forming a pattern on at least a portion of the mask carrier

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Data Source

PatentUS20250086366A1Computer implemented method for simulating an aerial image of a model of a photolithography mask using a machine learning model
Publication Date: 2025.03.13 CARL ZEISS SMT GMBH
  • US20250086366A1 patent drawing
  • US20250086366A1 patent drawing
  • US20250086366A1 patent drawing

AI summary

The invention relates to a computer implemented method for simulating an aerial image of a model of a photolithography mask illuminated by incident electromagnetic waves, the method comprising: obtaining the model of the photolithography mask; simulating the propagation of the incident electromagnetic waves through the model of the photolithography mask using a machine learning model, wherein the machine learning model maps the model of the photolithography mask to a representation of an electromagnetic field generated by the incident electromagnetic waves on the photolithography mask; obtaining the aerial image of the model of the photolithography mask by applying a simulation of an imaging process. The invention also relates to corresponding computer programs, computer-readable media and systems.