KR-102962189-B1 - NOISE EVALUATION APPARATUS AND METHOD FOR MICROSCOPY APPARATUS

KR102962189B1KR 102962189 B1KR102962189 B1KR 102962189B1KR-102962189-B1

Abstract

A device for evaluating the influence of noise acting on a microscope device, wherein the device is: The apparatus comprises a microscope device that detects a signal generated from a sample and forms a corresponding detection signal, a noise sensor unit that detects noise and forms a corresponding noise detection signal, and includes a mechanical noise sensor that detects mechanical noise and a magnetic field sensor that detects magnetic field noise, a control unit that generates a monitor signal corresponding to a driving signal of the microscope device, and a signal processing unit that performs signal processing by providing one or more of the noise detection signal and the monitor signal, wherein the signal processing unit calculates the relationship between one or more of the noise detection signal and the monitor signal and the detection signal.

Inventors

오가와 타카시
황준혁

Assignees

한국표준과학연구원

Dates

Publication Date: 20260511
Application Date: 20250612
Priority Date: 20240923

Claims (20)

A device for evaluating the influence of noise acting on a microscope device, wherein the device is: Microscope device that detects a signal generated from a sample and forms a corresponding detection signal; A noise sensor unit that detects noise and forms a corresponding noise detection signal, and includes a mechanical noise sensor that detects mechanical noise and a magnetic field sensor that detects magnetic field noise; A control unit that generates a monitor signal corresponding to the driving signal of the microscope device; and It includes a signal processing unit that performs signal processing by providing one or more of the noise detection signal and the monitor signal, and the signal processing unit, A device for calculating the relationship between one or more of the noise detection signal and the monitor signal and the detection signal.
In paragraph 1, The above microscope device is: A device that is any one of a Scanning Electron Microscope (SEM), Scanning Transmission Electron Microscope (STEM), Scanning Ion Microscope (SIM), Focused Ion Beam (FIB), Scanning Helium Ion Microscope (HIM), Scanning Probe Microscope (SPM), Atomic Force Microscope (AFM), and Scanning Tunneling Microscope (STM).
In paragraph 1, The above mechanical noise sensor is, A vibration sensor that detects ground vibrations, and A vibration sensor for detecting vibrations of the above-mentioned microscope device and A device comprising one or more of voice sensors that detect vibrations in the sound band.
In paragraph 3, The above vibration sensor and the above magnetic field sensor are a device that is a 3-axis sensor.
In paragraph 1, The above microscope device It includes one or more of a scanning unit, a stigmatizer, an alignment unit, a lens unit, an electronic source, and a high voltage source and a current source for driving, and The driving signal of the microscope device is one or more driving signals among the scanning unit, stigmat, alignment unit, lens unit, electron source, and high voltage source and current source for driving, and A device in which the above monitor signal is a signal corresponding to the above driving signal.
In paragraph 1, The above microscope device is, It further includes one or more of a secondary electron detector (SED), a reflection electron detector, a transmission electron detector, a sample absorption current detector, an X-ray detector, and an electron energy detector, and The above detection signal is, A device further comprising a signal formed by detecting the sample, wherein one or more of the above secondary electron detector (SED), reflection electron detector, transmission electron detector, sample absorption current detector, X-ray detector, and electron energy detector.
In paragraph 1, The above signal processing unit is, A device for calculating the correlation coefficient between one or more of the noise detection signal and the monitor signal and the detection signal.
In Paragraph 7, The correlation coefficient calculated by the signal processing unit above is, A device having one or more of the Pearson correlation coefficient, Spearman correlation coefficient, and distance correlation coefficient.
In paragraph 1, The above signal processing unit is, A device that displays the above noise, the above monitor signal, and the above detection signal in one or more of the time domain, the frequency domain and the frequency domain using the Welch method.
In paragraph 1, The above microscope device is, A probe is placed at any point of the above sample and a signal is detected by a detector, Position and scan a probe on any side of the above sample and detect a signal, A device for positioning and scanning a probe in an area containing at least a portion of the above sample, detecting and sensing a signal to form a detection signal.
In paragraph 1, The above processing unit is, Extracting one or more of the provided noise detection signal and the monitor signal, and a signal within a frequency band set in the detection signal, and A device for calculating the relationship between the extracted signal and the detected signal.
In Paragraph 11, The above processing unit is, An FFT operation unit that performs an FFT operation on one or more of the input noise detection signal and the monitor signal and the detection signal; A filter unit for extracting a signal within a set band; and A device comprising a preprocessing unit including an IFFT operation unit that performs an IFFT (Inverse FFT) operation on the output signal of a filter unit.
In Paragraph 12, The above filter unit is, A device for extracting a signal within a set band by applying one or more of a low-pass filter (LPF), a band-pass filter (BPF), and a high-pass filter (HPF) to one or more of the noise detection signal and the monitor signal provided above.
In Paragraph 11, The band set above is A device having a frequency band that includes a frequency band of noise affecting an image acquired by the above-mentioned microscope device.
A method for evaluating the influence of noise acting on a microscope device, the method is: The step of the microscope device detecting secondary electrons formed in a sample and forming a corresponding detection signal; A noise sensor including a mechanical noise sensor and a magnetic field sensor detects noise acting on the microscope device and forms a noise detection signal, and The step of generating a monitor signal corresponding to the driving signal of the microscope device, and A method comprising the step of a signal processing unit calculating the relationship between one or more of the noise detection signal and the monitor signal and the detection signal.
In paragraph 15, The above microscope device is: A method of any one of a Scanning Electron Microscope (SEM), Scanning Transmission Electron Microscope (STEM), Scanning Ion Microscope (SIM), Focused Ion Beam (FIB), Scanning Helium Ion Microscope (HIM), Scanning Probe Microscope (SPM), Atomic Force Microscope (BFM), and Scanning Tunneling Microscope (STM).
In paragraph 15, The above mechanical noise sensor is, A vibration sensor that detects ground vibrations, and A vibration sensor for detecting vibrations of the above-mentioned microscope device and A method including a voice sensor that detects vibrations in the sound band.
In Paragraph 17, A method in which the above vibration sensor and the above magnetic field sensor are 3-axis sensors.
In paragraph 15, The above microscope device It includes one or more of a scanning unit, an astigmatism correction unit, an alignment unit, a lens unit, an electronic source, and a high voltage source and a current source for driving. The driving signal of the microscope device is one or more driving signals among the scanning unit, astigmatism correction unit, alignment unit, lens unit, electron source, and high voltage source and current source for driving. A method in which the above monitor signal is a signal corresponding to the above driving signal.
In paragraph 15, The above microscope device is, It further includes one or more of a secondary electron detector (SED), a reflection electron detector, a transmission electron detector, a sample absorption current detector, an X-ray detector, and an electron energy detector, and The above detection signal is, A method further comprising a signal formed by detecting the sample using one or more of the above secondary electron detector (SED), reflection electron detector, transmission electron detector, sample absorption current detector, X-ray detector, and electron energy detector.

Description

Noise Evaluation Apparatus and Method for Microscope Apparatus The present disclosure generally relates to a noise evaluation apparatus and method for a charged particle beam device. A scanning electron microscope places a probe at a specific location on a sample and detects a signal. It scans the sample in two dimensions in the X and Y directions and measures the signal at each coordinate. Microscope images can be obtained by two-dimensional imaging the signal amount at each coordinate as a gray level. Among scanning microscopes, a microscope that uses an electron source as a light source, forms a probe by focusing an electron beam, and observes the surface of a sample using secondary electrons and reflected electrons generated from the sample as signals is called a scanning electron microscope (SEM). SEM and STEM, which utilize electron beams, are widely used in the fields of materials science, nanoscience, and electronics. Microscopic observation using charged particle beam devices allows for high spatial resolution, making it possible to observe structures too small to be seen with conventional optical microscopes, such as thin films grown on substrates, nanotubes, plasmonic structures, and the atomic arrangement of samples. Furthermore, charged particle beam devices enable the observation of the microstructures of biological samples, such as cells, and the identification of crystal structures through electron beam diffraction imaging. Scanning microscopes are devices used to observe the microstructure of a sample. With advancements in materials science, nanoscience, and electronics, there is a growing demand for observing finer structures. However, when a scanning microscope is set to high magnification to observe a sample at a greater scale, the resolution is often limited not only by the inherent resolution of the device due to probe dimensions but also by other factors. This limiting factor is referred to as microscope image noise. Such noise issues can occur after the microscope is installed at a customer site as a product, or they may arise during the research and development process of new microscope models. FIG. 1 is a diagram illustrating an overview of a device for evaluating the noise effect acting on the microscope device of the present embodiment. FIG. 2 is a flowchart schematically illustrating a method for evaluating the noise effect acting on the microscope device of the present embodiment. Figures 3 and 4 illustrate examples in which a microscope device provides a beam of charged particles to a sample and detects secondary electrons formed in the sample in order to identify the effect of noise. Figure 5 is a block diagram illustrating an overview of the preprocessing unit. FIG. 6 is a flowchart illustrating an overview of the pretreatment method of the present embodiment. Figures 7(a), 7(a), and 7(c) are drawings illustrating the state displayed to the user by calculating the correlation coefficient. FIG. 8(a) is a diagram showing input signals in the time domain, FIG. 8(b) is a diagram showing input signals in the frequency domain, and FIG. 8(c) is a diagram showing signals in the frequency domain using the Welch method. The present embodiment will be described below with reference to the attached drawings. FIG. 1 is a diagram illustrating an overview of a device for evaluating the noise effect acting on a microscope device of the present embodiment. Referring to FIG. 1, the device (10) for evaluating the noise effect acting on a microscope device of the present embodiment comprises: a microscope device (100) that detects a signal generated from a sample and forms a corresponding detection signal; a noise sensor unit that detects noise and forms a corresponding noise detection signal, and includes mechanical noise sensors (214, 216, 218) and a magnetic field sensor (212); and a control unit (180) that generates a monitor signal (mon) corresponding to the driving signal of the microscope device. The system includes a signal processing unit (300) that performs signal processing by providing at least one of the noise detection signals (n_mech1, n_mech2, n_mech3, n_mag) and the monitor signal (mon), and the signal processing unit (300) calculates the relationship between at least one of the noise detection signals (n_mech1, n_mech2, n_mech3, n_mag) and the monitor signal (mon) and the detection signal (det1). In the illustrated embodiment, the microscope device (100) is a scan electron microscope. However, the microscope device of the present embodiment is not limited thereto and may be a Scanning Transmission Electron Microscope (STEM) which detects a signal transmitted through a sample and uses a thin film as the sample, a Scanning Ion Microscope (SIM) which uses an ion source as a light source, focuses an ion beam to form a probe, and detects secondary electrons generated from the sample, a Focused Ion Beam (FIB) which is a Scanning Ion Microscope that uses a liquid metal ion source suc