SEM Image Charging Compensation Using a Diffusion-Based Model

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Scanning electron microscopy (SEM) images of electrically insulating materials suffer from SEM-induced charging artifacts, leading to charge-induced critical dimension errors and inaccuracies in defect detection, with existing techniques having limitations such as low throughput and lack of physics-based explainability.

Innovation Solution

A method and system that acquire SEM images, simulate diffused charge associated with image positions, and provide enhanced images by compensating for charging artifacts using a diffusion-based model and compensation relationship, which is computationally efficient and provides intuitive explanations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If coating a target sample surface with a conducting material is used to reduce charging artifacts, then charging artifacts are reduced, but device complexity and sample preparation time increase

Engineering Contradiction:
Improvecharging artifactsVSAvoidsample preparation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces physical/sample-based charging reduction methods (coating, grounding) with a computational image processing system. The diffusion-based model numerically simulates and removes charging artifacts from SEM images, substituting physical interventions with algorithmic correction. This eliminates the need for additional sample preparation steps while achieving charging artifact reduction.

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

Solution Approach 2:

The patent introduces a diffusion-based computational model as an intermediary between the SEM imaging process and the final image output. This model acts as a mediator that processes the raw SEM image data, simulating charge diffusion patterns and removing artifacts without requiring physical modification of the sample or imaging hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If using faster scanning with lower dose per SEM frame is used to reduce charging artifacts, then charging artifacts are reduced, but image quality and signal-to-noise ratio deteriorate

Engineering Contradiction:
Improvecharging artifactsVSAvoidimage quality
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent replaces dose-reduction scanning methods with a post-processing computational approach. Instead of modifying the scanning parameters to reduce charging, the system captures images at optimal doses and then uses diffusion-based modeling to remove charging artifacts in the image processing stage, preserving image quality while eliminating artifacts.

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

3Object-affected harmful factors

If using pseudo random scans is used to reduce charging artifacts, then charging artifacts are reduced, but throughput decreases and productivity is lowered

Engineering Contradiction:
Improvecharging artifactsVSAvoidinspection throughput
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent performs charging artifact removal as a preliminary or concurrent processing step rather than requiring slow pseudo-random scanning patterns. By using a diffusion-based model that can process images efficiently, the system maintains normal scanning speeds while removing artifacts through computational correction, thus preserving throughput.

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If machine learning techniques are used to remove charging artifacts, then charging artifacts are reduced, but lack of physics-based explainability and insights into training processes occurs

Engineering Contradiction:
Improvecharging artifactsVSAvoidphysics-based explainability
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent uses a diffusion-based physical model with explicit parameters (diffusion coefficient, time, spatial coordinates) to describe charge behavior. This physics-based approach provides interpretability through well-defined parameters and equations, contrasting with black-box machine learning while achieving similar artifact removal效果. The model's parameters can be directly related to physical charge diffusion processes.

Inventive Principle:
Principle #35Parameter changes

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 SEM-induced charging artifacts, improving the accuracy of defect detection and enhancing the faithfulness of SEM images, thereby increasing the yield and precision in manufacturing processes.

Implementation Method 1

simulating diffused charge associated with a position of the SEM image

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12255042B2Numerically compensating SEM-induced charging using diffusion-based model
Publication Date: 2025.03.18 ASML NETHERLANDS BV
  • US12255042B2 patent drawing
  • US12255042B2 patent drawing
  • US12255042B2 patent drawing

AI summary

Systems and methods for image enhancement are disclosed. A method for enhancing an image may include acquiring a scanning electron microscopy (SEM) image. The method may also include simulating diffused charge associated with a position of the SEM image. The method may further include providing an enhanced SEM image based on the SEM image and the diffused charge.