SEM Line-Width Measurement Adjustment via Beam Intensity Equalization

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Solution Overview

Problem

Scanning electron microscopes face fluctuations in line-width measurement results due to changes in magnification, beam diameter, and scanning direction, making it difficult to achieve consistent measurements across different observation scales and devices.

Innovation Solution

A method to adjust the electron beam intensity distribution by equalizing the irradiation distances and beam diameters, ensuring consistent line-width measurements by adjusting the electron beam intensity distribution to match the standard distribution at different magnifications and scanning directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high magnification of observation is used, then measurement detail is improved, but the irradiation range is reduced causing measurement result variation

Engineering Contradiction:

Improveline-width measurement precisionVSAvoidirradiation range

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent applies parameter changes by adjusting the electron beam intensity distribution parameters to compensate for magnification changes. Specifically, when magnification changes, the system modifies the electron beam intensity distribution to maintain consistent measurement conditions, thereby resolving the contradiction between maintaining measurement precision and managing the irradiation range at different magnifications

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If beam diameter is changed, then scanning coverage is improved, but measurement consistency deteriorates

Engineering Contradiction:

Improvescanning coverageVSAvoidmeasurement consistency

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent uses parameter changes by adjusting the electron beam intensity distribution parameters based on beam diameter variations. The system detects beam diameter changes and compensates by modifying the intensity distribution parameters, thereby maintaining measurement consistency while allowing flexible scanning coverage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by measuring the actual beam diameter and using this information to adjust the electron beam intensity distribution. The system continuously monitors beam parameters and makes real-time adjustments to maintain measurement consistency, resolving the contradiction between scanning coverage and measurement consistency

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If different scanning directions are used, then measurement versatility is improved, but measurement result variation increases

Engineering Contradiction:

Improvescanning direction flexibilityVSAvoidmeasurement result consistency

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by adjusting the electron beam intensity distribution parameters according to the scanning direction. The system detects the scanning direction and modifies the intensity distribution parameters accordingly, thereby maintaining measurement result consistency while supporting versatile scanning directions

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

This approach stabilizes line-width measurement results across varying magnifications and devices, allowing for efficient measurement of line widths even at lower magnifications and across different scanning directions, reducing errors and improving measurement accuracy.

Implementation Method 1

irradiating incident electrons, to acquire secondary electrons emitted from a sample by using a scintillator

Methodology Applied

Scientific EffectSecondary electron emission: Photoelectric Effect

Implementation Method 2

a scanning electron microscope is configured to scan an electron beam scanning range by irradiating incident electrons

Methodology Applied

Scientific EffectElectron beam scanning: Electron Beam

Data Source

PatentUS7663103B2Line-width measurement adjusting method and scanning electron microscope

Publication Date: 2010.02.16 ADVANTEST CORP

AI summary

A line-width measurement adjusting method, which is used when first and second electron beam intensity distributions for measuring a line width are produced from intensity distribution images of secondary electrons obtained respectively by scanning a first irradiation distance with an electron beam at first magnification, and by scanning a second irradiation distance with an electron beam at second magnification, includes the step of adjusting the second electron beam intensity distribution of the electron beam at the second magnification such that the second electron beam intensity distribution is equal to the first electron beam intensity distribution of the electron beam at first magnification. The second electron beam intensity distribution may be adjusted by increasing or decreasing a second irradiation distance when producing the electron beam intensity distribution.