Charged Particle Beam Drift Correction for EMI-Stable Microscopy

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Solution Overview

Problem

Electromagnetic interference (EMI) during charged particle beam imaging of integrated circuits causes beam shifts and blurring, making imaging and data acquisition difficult, particularly in scanning electron microscopy, due to magnetic fields induced by device current variations.

Innovation Solution

A method to localize defects by generating drift information from charged particle beam sequences, determining deflection vectors, and applying correction vectors to stabilize the beam position, using beam steering commands to counteract EMI effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If charged particle beam imaging is performed on integrated circuits with periodic test signals, then circuit performance can be examined under different operating conditions, but electromagnetic fields generated by device current variations cause beam shifts and blurring that degrade image quality and measurement precision

Engineering Contradiction:

Improvecircuit performance examination under different operating conditionsVSAvoidimage quality and measurement precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary characterization of electromagnetic interference by capturing a sequence of images and tracking feature positions to determine drift vectors before actual measurement. This preliminary drift characterization allows the system to predict and compensate for beam shifts during subsequent imaging, enabling both circuit testing under various conditions and maintenance of measurement precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring beam position through image sequence analysis, calculating drift vectors from tracked feature positions, and applying correction vectors to subsequent beam steering commands. This closed-loop feedback mechanism compensates for electromagnetic field-induced beam shifts in real-time, maintaining image quality during circuit performance examination

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If device current varies over the test loop to examine circuit performance, then different operating conditions can be tested, but magnetic fields created by current variations unintentionally steer the electron beam away from its desired target

Engineering Contradiction:

Improvetesting under different operating conditionsVSAvoidbeam positioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The system performs preliminary drift characterization by capturing images during circuit testing and tracking feature positions to determine drift vectors before actual defect localization. This preliminary action establishes a baseline understanding of how electromagnetic fields affect beam positioning under specific test conditions, enabling accurate compensation during subsequent measurements

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes beam steering parameters dynamically by applying correction vectors derived from drift information. These parameter adjustments compensate for electromagnetic field effects on beam positioning, allowing the beam to maintain accurate positioning despite variations in device current and operating conditions during circuit testing

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If beam steering is used to maintain image quality during EMI, then beam position can be corrected, but additional complexity is introduced in drift information generation and correction vector application

Engineering Contradiction:

Improvebeam position accuracyVSAvoiddrift information generation and correction system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the imaging system's own captured images to generate drift information, rather than requiring external reference systems or additional sensors. By tracking features within the images already being captured for circuit testing, the system self-characterizes electromagnetic interference effects and generates correction vectors from its own operational data, adding minimal complexity while maintaining beam position accuracy

Inventive Principle:

Principle #25Self-service

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

Improves image accuracy and precision by stabilizing the beam position, allowing for precise imaging and data acquisition despite EMI, enhancing the resolution and reliability of charged particle microscopy systems.

Implementation Method 1

generating drift information for a drift of the beam of charged particles in one or more directions, the drift being induced at least in part by an electromagnetic field in a vicinity of the sample

Methodology Applied

Scientific EffectElectromagnetic field: Electromagnetic Induction

Data Source

PatentUS20250347641A1Techniques for reducing electromagnetic interference effects in charged particle microscopy

Publication Date: 2025.11.13 FEI CO

AI summary

Embodiments of the present disclosure improve the performance of charged particle beam systems during imaging and/or microanalysis, at least in part by permitting a system and/or user to account for the influence of electromagnetic interference on beam direction and/or shape. Techniques are described for identifying, tracking, and/or correcting electromagnetic interference-induced beam drifts, as well as techniques for localizing defects in integrated circuit devices.