Substrate Region Classification Using LEEPP for Defect Screening

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Solution Overview

Problem

Graphene substrates used for low-energy electron holography and similar transmission mode analytic procedures are compromised by surface contaminants and structural defects, leading to reduced imaging performance and yields.

Innovation Solution

Implementing low-energy electron point projection (LEEPP) imaging to identify and classify substrate regions for analyte deposition, using sparse and secondary scans to optimize coverage and deposition patterns, and employing a trained machine learning tool for consistent image classification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a comprehensive scan of the entire substrate is performed to ensure complete coverage, then the coverage of substrate area is improved, but the scan time increases significantly

Engineering Contradiction:
Improvesubstrate coverageVSAvoidscan time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The substrate is divided into multiple regions or tiles that are scanned systematically. The scanning process is segmented into passes over different portions of the substrate, allowing efficient coverage without requiring a single continuous scan of the entire area. This segmentation enables the system to achieve complete coverage while managing scan time through structured progression across substrate regions.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the scanning resolution is increased to improve image quality, then the measurement precision is improved, but the scan time increases

Engineering Contradiction:
Improveimage qualityVSAvoidscan time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs scanning at variable resolutions depending on the requirements of different substrate regions. Instead of uniformly applying high resolution across the entire substrate, the system applies partial scanning at high resolution only where needed (such as in regions containing analyte particles), while using lower resolution scanning in other areas. This selective approach maintains measurement precision for critical regions while reducing overall scan time.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If substrate regions are classified to identify suitable regions for analyte deposition, then the productivity is improved by reducing scan time, but the manufacturing precision may be compromised

Engineering Contradiction:
Improvescan efficiencyVSAvoidregion classification accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The substrate regions are classified and pre-sorted before analyte deposition to identify and select only the most suitable regions. This preliminary classification action filters out unsuitable regions (those with defects or contaminants) in advance, allowing the deposition process to focus only on high-quality regions. This approach improves productivity by reducing the search space while maintaining manufacturing precision through systematic evaluation of region suitability criteria.

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

Enhances the yield of analyte characterization data by identifying suitable substrate regions efficiently, reducing scan time, and improving image classification accuracy, thereby maintaining high-quality imaging performance.

Implementation Method 1

low-energy electron point projection (LEEPP) imaging

Methodology Applied
Scientific EffectElectron transmission: Electron Beam

Data Source

PatentEP4660940A1Classification of substrate regions
Publication Date: 2025.12.10 FEI CO
  • EP4660940A1 patent drawingFigure 1
  • EP4660940A1 patent drawingFigure 2
  • EP4660940A1 patent drawingFigure 3

AI summary

Methods and apparatus are disclosed for classifying regions of a substrate prior to performing an analytic procedure involving analyte particles supported on the substrate. Regions of the substrate are sparsely scanned using low-energy electron point projection (LEEPP) imaging. Regions are classified as suitable for the analytic procedure (or not) based on defects visible in the respective images. Given one suitable region, neighboring regions are scanned to increase the yield of suitable regions. Based on a distribution of suitable regions, a deposition pattern is planned, and analyte is deposited according to the plan. Following deposition, suitable regions are scanned again to identify or count visible analyte molecules visible. Based on numbers of analyte molecules found, regions are earmarked for analyte characterization, e.g. by low-energy electron holography and reconstruction. A trained machine learning classifier provides consistent, accurate image classification across a range of defect types.