CDSEM Pattern ROI Denoising with 1D AI Scanlines

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Solution Overview

Problem

Existing CDSEM denoising techniques, including 2D AI-based solutions, are inefficient in terms of time and accuracy, failing to meet semiconductor industry demands for high throughput and precise measurement of critical dimensions.

Innovation Solution

A 1D AI denoising method using gaussian weighted averaging and deep learning neural networks to process scanlines, involving augmentation and noise addition, followed by iterative parameter updating to create a noise discrimination function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If 2D AI-based denoising techniques are used, then denoising capability is improved, but processing time increases significantly

Engineering Contradiction:
Improvedenoising capabilityVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the 2D image denoising problem into multiple 1D scanline denoising operations. Each scanline is processed independently through the trained 1D AI model, avoiding the computational burden of 2D processing while maintaining effective denoising. This segmentation approach reduces processing time significantly while preserving the essential denoising functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from 2D denoising to 1D denoising by changing the dimensionality of the processing approach. Instead of applying AI models to two-dimensional image data, the patent processes one-dimensional scanline waveforms, reducing computational complexity and processing time while achieving comparable or superior denoising results for CD measurement applications.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If 2D AI denoising models are trained, then denoising performance is improved, but training time increases to ten or more minutes

Engineering Contradiction:
Improvedenoising performanceVSAvoidtraining time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the training process by creating 1D AI models that process individual scanlines rather than training complex 2D models on entire images. This segmentation allows for faster model creation and training while maintaining effective denoising performance for the specific application of CD measurement on scanline data.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter dimensionality from 2D to 1D, fundamentally altering the model architecture and training requirements. This parameter change reduces the complexity of the training process, enabling rapid model creation that takes seconds rather than minutes, while still achieving superior denoising results for the target application.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If classical 2D denoising techniques are used, then denoising is achieved, but precision and accuracy are insufficient for CD measurement

Engineering Contradiction:
Improvedenoising efficiencyVSAvoidprecision and accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces classical mechanical filtering techniques with AI-based denoising. The trained 1D AI model learns optimal denoising parameters and patterns from training data, substituting fixed mechanical filtering algorithms with adaptive intelligent processing that achieves superior precision and accuracy for CD measurement applications.

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

Solution Approach 2:

The patent performs preliminary training of the 1D AI model using augmented scanline data before actual denoising operations. This preliminary action of training the model with diverse synthetic data prepares it to handle various noise conditions, ensuring high precision and accuracy in subsequent measurements without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

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

Significantly reduces denoising time and improves precision and accuracy in CDSEM measurements by leveraging 1D AI denoising, enabling faster and more accurate critical dimension metrology.

Implementation Method 1

scanning an electron beam across a pattern of interest on a substrate; detecting a single scan line waveform of the scanned electron beam

Methodology Applied
Scientific EffectElectron beam scanning: Electron Beam

Data Source

PatentUS12437372B2System and method for denoising a region of interest of a pattern
Publication Date: 2025.10.07 ETROLOGY LLC
  • US12437372B2 patent drawing
  • US12437372B2 patent drawing
  • US12437372B2 patent drawing

AI summary

A system and method for denoising a grey scale image of a pattern on a substrate, including: scanning an electron beam along a pattern, detecting a scan line waveform from the scanned electron beam, obtaining a model scan line waveform from the detected scan line waveform, augmenting the model scan line waveform and adding noise to the augmented model scan line waveform, inputting the noisy augmented model scan line through a deep learning neural network (DNN) process, comparing the output of the DNN process to the augmented model scan line waveform before noise is added, and backpropagating the compared results into the DNN process to obtain a noise discrimination function.