Fine Particle Shape Correction Using Standard Reference Particles
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Solution Overview
Problem
Current methods for measuring fine particles fail to provide reproducible data and accurately evaluate particle shape and type due to probe shape effects and aggregation issues, leading to incomplete shape information and lack of material identification.
Innovation Solution
A particle measuring device and method using a scanning electron microscope, where standard fine particles are disposed near the particles to be measured on the same substrate, allowing for accurate shape correction and type evaluation by processing detection signals to generate and correct particle images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard fine particles and fine particles to be measured are disposed on different substrates and measured alternately, then probe shape effect correction can be performed, but measurement reproducibility deteriorates due to probe wear between measurements
Solution Approach 1:
The patent merges the measurement of standard fine particles and fine particles to be measured into a single substrate, allowing both types of particles to be measured simultaneously in one scanning process. This eliminates the need for alternate measurements on different substrates, thereby preventing probe wear from affecting measurement consistency while still enabling probe shape effect correction through the presence of standard particles in the same measurement field.
2Measurement precision
If fine particles are dispersed in suspension and dropped onto substrate, then particle sampling is achieved, but particle aggregation occurs leading to inaccurate shape measurement
Solution Approach 1:
The patent applies preliminary action by pre-modifying the substrate surface with specific functional groups (such as carboxyl, hydroxyl, or amino groups) before dropping the particle suspension. This surface modification creates optimal adhesion conditions that prevent particle aggregation during the drying process, ensuring particles remain isolated and maintain their original shapes for accurate measurement.
3Measurement precision
If SPM or charged particle microscope is used for shape measurement, then fine particle shape can be evaluated, but probe shape effect or beam intensity profile causes measurement error
Solution Approach 1:
The patent introduces standard fine particles with known, precisely controlled shapes as intermediary reference objects in the measurement system. These standard particles serve as mediators to calibrate and correct the probe shape effect or beam intensity profile, allowing the extraction of true shape information from the measured data by comparing against the known standard particle geometry.
4Productivity
If particle diameter is measured without considering probe shape effect, then measurement process is simple, but measurement accuracy deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-establishing a correction algorithm based on standard particle measurements before actual particle diameter measurement. The system automatically applies this correction to subsequent measurements, maintaining high measurement speed while improving accuracy through the pre-computed probe shape effect compensation.
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
Enables reproducible and accurate measurement of fine particle shape and type, reducing probe wear influence and improving data reliability by correcting shape information and discriminating particle types based on shape and physical properties.
Implementation Method 1
a detector configured to detect secondary charged particles obtained by scanning a surface of a substrate on which an isolated fine particle to be measured and an isolated standard fine particle in the vicinity thereof are disposed with an electron beam probe
Data Source
AI summary
To enable evaluation of a shape of a fine particle and a fine particle type, a substrate is set as a substrate on which an isolated fine particle to be measured and an isolated standard fine particle in the vicinity of the isolated fine particle to be measured are disposed, and a scanning electron microscope body including a detector configured to detect secondary charged particles obtained by scanning a surface of the substrate with an electron beam probe, and a computer that processes a detection signal and generates an image of the isolated fine particle to be measured and the isolated standard fine particle are provided. The computer corrects a shape of the isolated fine particle to be measured by using a measurement result of the isolated standard fine particle disposed in the vicinity of the isolated fine particle to be measured. Further, by attaching a fine particle spreading tank equipped with a fine particle suspension dropping device inside the microscope body, automatic measurement including dropping of fine particle suspension onto a surface of a surface-modified substrate is possible.