Specimen Surface Analysis Using Coarse Fine Grid Segmentation
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Solution Overview
Problem
Conventional automated particle analysis in scanning electron microscopes is inefficient due to the need to scan large areas, which results in wasted time and resources when no interesting particles are found, as the entire specimen surface must be surveyed with high precision, even if only a small portion contains features of interest.
Innovation Solution
A method involving a preliminary survey with reduced precision to quickly identify features of interest across the specimen surface, followed by a targeted second survey with higher precision on selected areas, optimizing the order and conditions for data collection based on the preliminary survey's analytical data to minimize overall analysis time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fine grid is used to scan the entire specimen surface with high precision, then measurement precision of particle morphology is improved, but analysis time increases significantly
Solution Approach 1:
The patent divides the specimen surface into multiple regions and performs scanning in stages. A first survey scans the entire surface with a coarse grid to identify regions containing particles of interest, then a second survey scans only those specific regions with a fine grid to obtain high-precision morphology data. This segmentation approach maintains measurement precision for particles while dramatically reducing the area requiring high-resolution scanning, thus solving the time-precision contradiction.
Solution Approach 2:
The patent applies different scanning densities to different regions of the specimen. Regions identified as containing particles of interest receive high-density fine grid scanning for accurate morphology measurement, while regions without particles receive only low-density coarse grid scanning. This local differentiation ensures high measurement precision where needed while minimizing unnecessary high-precision scanning in empty areas, thereby reducing overall analysis time.
2Reliability
If the entire specimen surface is surveyed with high precision, then all particles are detected, but time and resources are wasted when no interesting particles are found
Solution Approach 1:
The patent performs a preliminary survey (first survey) of the entire specimen surface using a coarse grid to identify regions containing particles of interest before conducting detailed high-precision scanning. This preliminary action allows the system to locate particles efficiently and then concentrate resources only on regions where particles are found, ensuring detection completeness while avoiding wasteful high-precision scanning of empty areas.
Solution Approach 2:
The patent initially performs a less intensive coarse grid scan covering the entire specimen surface to identify particle locations, then performs a more intensive fine grid scan only on the identified regions containing particles. This partial application of high-precision scanning—applying it only where necessary rather than uniformly across the entire surface—maintains reliable particle detection while significantly reducing the total time and resources required.
3Productivity
If a coarse grid is used for fast scanning, then analysis speed is improved, but measurement precision of particle morphology deteriorates
Solution Approach 1:
The patent segments the scanning process into two distinct phases: a first survey using a coarse grid for fast scanning to identify particle locations, and a second survey using a fine grid for high-precision morphology measurement. This segmentation allows the system to achieve high scanning speed during the initial survey phase while maintaining high measurement precision during the subsequent detailed scanning phase of particles that are actually present.
Solution Approach 2:
The patent applies different grid densities to different spatial regions based on particle presence. Regions identified as containing particles receive fine grid scanning for high-precision morphology measurement, while regions without particles are scanned with coarse grids for speed. This local differentiation resolves the contradiction by ensuring high measurement precision is applied only where particles are located, while maintaining high scanning speed in particle-free regions.
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 significantly reduces the total analysis time by prioritizing data collection on areas with higher feature density, minimizing unnecessary data collection, and allowing for faster coverage of the specimen surface while maintaining the required accuracy for feature analysis.
Implementation Method 1
When a focussed electron beam strikes a specimen, signals are generated that are representative of the material excited by incident electrons
Implementation Method 2
The signal from a backscattered electron detector (BSED) is sensitive to the mean atomic number of the material and if the electron beam strikes a contaminant particle containing heavy elements, the signal will be strong
Data Source
Figure 1
Figure 2(a)~2(f)
Figure 3~4(b)
AI summary
A method and apparatus for analysis of a specimen in a microscope are provided. A first survey is performed that collects analytical data from a region of interest on the specimen surface using a first set of conditions. A second survey is performed that collects additional analytical data from selected parts of the region of interest on the specimen surface using a second set of conditions, different from the first set of conditions. The analytical data from the first survey is used to select the parts used for data collection in the second survey and to decide the order in which they are used.