Multiple Beam Electron Image Correction via Feedback Trajectory

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Solution Overview

Problem

In multiple beam image acquisition systems, positional deviations in electron beams lead to distortion and gray scale variations in acquired images, making precise inspection challenging due to interference and trajectory errors.

Innovation Solution

A multiple beam image acquisition apparatus and method that includes a stage, beam forming mechanism, primary and secondary electron optical systems, a multi-detector, and a correction mechanism to measure and correct the trajectory of secondary electron beams using a measurement secondary electron beam, ensuring accurate detection and image precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple primary electron beams are used to scan the target object simultaneously, then productivity is improved, but measurement precision deteriorates due to trajectory deviation and positional errors

Engineering Contradiction:

Improveimage acquisition speedVSAvoidbeam position accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent employs a feedback mechanism where the measured position information of secondary electron beams is fed back to the correction mechanism, which then adjusts the trajectory of subsequent beams to compensate for detected deviations, thereby maintaining measurement precision while using multiple beams for high productivity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary measurement of secondary electron beam positions before actual image acquisition, and uses this information to pre-correct trajectories, ensuring that beams are properly aligned before they scan the target object

Inventive Principle:

Principle #10Preliminary action

2Productivity

If multiple primary electron beams are used for scanning, then productivity is improved, but manufacturing precision deteriorates due to image distortion and gray scale variations

Engineering Contradiction:

Improveinspection throughputVSAvoidimage quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The correction mechanism uses real-time feedback from position measurements to adjust beam trajectories, compensating for disturbances that would otherwise cause image distortion and gray scale variations, thus maintaining manufacturing precision while achieving high productivity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical alignment adjustments with a correction mechanism that uses measured position information to electronically correct beam trajectories, eliminating the need for physical realignment and preventing mechanical errors from affecting image quality

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If trajectory correction is performed using measured position information, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvebeam trajectory accuracyVSAvoidsystem structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The correction mechanism serves multiple functions: it corrects beam trajectories based on position measurements, compensates for environmental disturbances, and maintains alignment across all multiple beams simultaneously, thereby achieving high precision without proportionally increasing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a correction mechanism as an intermediary between the beam forming mechanism and the target object, which acts as a mediator to adjust and optimize beam trajectories without requiring complex modifications to the entire system architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution enables highly precise detection and correction of electron beam trajectories, reducing distortion and gray scale variations, thereby enhancing the accuracy of image acquisition and inspection processes.

Implementation Method 1

multiple secondary electron beams generated because the target object is irradiated with the multiple primary electron beams

Methodology Applied

Scientific EffectSecondary electron emission: Electron Impact Desorption

Data Source

PatentUS10777384B2Multiple beam image acquisition apparatus and multiple beam image acquisition method

Publication Date: 2020.09.15 NUFLARE TECH INC

AI summary

A multiple beam image acquisition apparatus includes a stage to mount thereon a target object, a beam forming mechanism to form multiple primary electron beams and a measurement primary electron beam, a primary electron optical system to collectively irradiate the target object surface with the multiple primary electron beams and the measurement primary electron beam, a secondary electron optical system to collectively guide multiple secondary electron beams generated because the target object is irradiated with the multiple primary electron beams, and a measurement secondary electron beam generated because the target object is irradiated with the measurement primary electron beam, a multi-detector to detect the multiple secondary electron beams collectively guided, a measurement mechanism to measure a position of the measurement secondary electron beam collectively guided, and a correction mechanism to correct a trajectory of the multiple secondary electron beams by using a measured position of the measurement secondary electron beam.