JP2000227404A - Analysis of enclosure in specimen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly shorten an analyzing time by scanning the whole of a specimen with an electron beam diameter of a size of one pigment for finding location of an enclosure to be analyzed and reducing the beam diameter for surface-analyzing the location area in detail. SOLUTION: Firstly, an electron beam diameter is set to be substantially equal to that of one pigment, and the specimen whole surface ABCD is surface- analyzed by stage scanning for rough analysis roughly determining whether an enclosure exists or not and for estimating its location. In this case, A11, A12,... AMN represent pigments in surface-analysis based on stage scanning, and AJK represents a pigment including an enclosure. Then, an area large enough for covering a pigment area abed including the enclosure is surface-analyzed with an electron beam diameter reduced for finely analyzing the enclosure. In this case, a11, a12,... aMN represent respective pigments in surface-analysis based on beam scanning. In this way, the enclosure is analyzed in two steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for analyzing inclusions in a sample using an analyzer such as an electronic probe microanalyzer.

[0002]

2. Description of the Related Art Conventionally, non-destructive inclusion analysis in steel, metal, semiconductor devices, and the like has been widely performed using analysis equipment such as an electron probe microanalyzer. It is one. In analyzing such inclusions, generally, the analysis region of the sample is two-dimensionally scanned with the electron beam through the sample stage, or the electron beam is scanned with the electron beam over the analysis region of the sample.
2. Description of the Related Art A technique of performing a large number of surface analyzes to collect an X-ray image of a sample by performing dimensional scanning has been used.

[0003]

The inclusions in the sample are rarely uniformly distributed over the entire area of the sample, and in most cases, are concentrated on a very limited portion of the sample. It always exists. However, since it is often not known or inclusions in advance which parts are present, for inclusion analysis be carried out surface analysis of vast number over the entire surface of the sample actually in which Only a small number of analysis results are used, and most of the analysis time is used to analyze the region where no inclusions are present, resulting in very inefficient inclusion analysis.

[0004] Further, even if the location of the inclusion is determined, if a wavelength dispersion type spectroscope is used for performing a surface analysis for obtaining a detailed element distribution, the wavelength dispersion type spectrometer is used. When the surface analysis by electron beam scanning is performed,
With respect to a line image, there is a problem in that the spectroscope deviates from the Roland circumference giving the X-ray diffraction conditions, thereby causing image unevenness and making it difficult to obtain a correct surface analysis result. Note that the low magnification is, for example, a magnification of 2000 times or less, and this value has a property that varies depending on measurement conditions such as the type of the used spectral crystal.

The present invention has been made to solve the above-mentioned problems in the conventional sample inclusion analysis method.
An object of the invention according to claim 1 is to provide a method for analyzing inclusions in a sample, which can greatly reduce the analysis time. Further, the invention according to claims 2 and 3 provides a method for analyzing inclusions in a sample, which can perform an appropriate analysis using an appropriate analysis technique or a scanning technique according to the aspect of the inclusion or the scanning magnification. With the goal.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a sample test on which a sample is placed, a means for generating an electron beam for irradiating the sample, a sample test and an electron beam. In a method of analyzing inclusions in a sample using a sample analyzer having scanning means for scanning the sample and means for measuring at least the intensity of X-ray signals and reflected electrons generated from the sample, the electron beam diameter is first set to A rough analysis step of roughly scanning the entire sample with a size of about one pixel to locate the inclusions to be analyzed, and then covering the area where the inclusions are present And performing a detailed surface analysis by reducing the diameter of the electron beam to such an extent that the electron beam can be obtained.

[0007] As described above, at least first, a rough scan is performed to perform a rough analysis for locating the inclusions, and then a detailed surface analysis is performed on a region where the inclusions are present. Can be shortened.

According to a second aspect of the present invention, there is provided the method for analyzing inclusions in a sample according to the first aspect, wherein an X-ray signal or a reflected electron is reflected depending on whether the inclusions in the sample can be analyzed and identified and the concentration of the inclusions. The invention is characterized in that inclusions are analyzed by selectively using an analysis method for measuring intensity, and the invention according to claim 3 is the method for analyzing inclusions in a sample according to claim 1 or 2. , Wherein inclusions are analyzed by selectively using sample stage scanning or electron beam scanning according to the size of inclusions in the sample, the method of analyzing inclusions, and the scanning magnification. .

As described above, by using an appropriate analysis method or scanning method according to the aspect of the inclusion or the scanning magnification, it becomes possible to perform an accurate analysis of the inclusion, and furthermore, it is possible to perform a stable data processing, for example, a statistical analysis. Processing, particle analysis processing, and the like.

[0010]

Next, an embodiment will be described. FIG. 1 is a schematic configuration diagram schematically showing an electron probe microanalyzer used for performing the method for analyzing inclusions in a sample according to the present invention. In FIG. 1, 1 is an electron gun, 2 is Wehnelt, 3 is a deflection coil, 4 is a motor for driving an X-ray spectroscope, 5 is an X-ray spectral crystal, 6 is an X-ray detector,
The X-ray spectroscope driving motor 4, the X-ray spectroscopic crystal 5, and the X-ray detector 6 constitute a WDS (wavelength dispersive X-ray spectrometer) detector. 7 is a backscattered electron detector, 8 is a secondary electron detector,
9 is an EDS (energy dispersive X-ray spectrometer) detector, 10
Is an analysis sample, 11 is a sample stage, 12 is a motor for driving the stage X-axis, 13 is a motor for driving the stage Y-axis, 14 is a motor for driving the stage Z-axis, 15 is a deflection coil controller, 16 is X
A motor controller for driving the X-ray spectroscope, 17 is a motor controller for driving the stage, 18 is a secondary electron / reflected electron signal data acquisition device, 19 is a WDSX-ray signal data acquisition device, 20 is E
DSX-ray signal data acquisition device, 21 is a central processing unit (C
PU), 22 is a mass storage device, and 23 is a joystick for stage manual drive.

The electronic probe microanalyzer comprising such components has the following functions by automatic control using a CPU, in addition to a normal electronic probe microanalyzer function. That is, digital control of electron beam scanning, scanning magnification, electron beam diameter, and the like can be performed, and drive measurement control of a plurality of WDSs and measurement control of one EDS can be performed. In addition, it is possible to measure and control the intensity of electron signals such as secondary electrons / reflected electrons, and to control each direction (X,
Driving control in the Y- and Z-axis directions is possible, and it is possible to collect surface analysis data of an X-ray signal and an electronic signal by scanning a sample stage and scanning an electron beam.

Next, a method for analyzing inclusions in a sample using the above-configured electronic probe microanalyzer will be described. Although it depends on the size of the inclusions, as shown in FIG. 2A, generally, first, the electron beam diameter is set to a size of about one pixel, and the surface of the sample is analyzed by surface analysis over the ABCD by stage scanning. Then, a rough analysis is performed to roughly determine whether an inclusion exists and, if so, on which side it exists. In FIG. 2A, A ₁₁ , A
_12, the · · · · · A _MN pixels in the case of performing surface analysis in stage scan, A _JK represent pixels that are present in the inclusions. Next, as shown in FIG. 2B, a surface analysis by electron beam scanning is performed on the pixel region abcd in which the inclusion is present over a size enough to cover the region. Perform the analysis with a small diameter and detailed inclusion analysis. In FIG. 2B, a ₁₁ ,
a ₁₂ ,..., a _mn represent each pixel when performing surface analysis by beam scanning.

For example, if the size of the inclusion has a spread of about 1 to 10 μm, the pixel length on one side is 1 to 10 μm.
First, a surface analysis by stage scanning is performed at about 10 microns. This coarse analysis locates the inclusion with the signal that best reflects the characteristics of the inclusion. For example, if the inclusions in the sample are composed of different substances compared to the surrounding substances, the presence of the inclusions can be identified by the magnitude of the X-ray signal of the substance element, and the average can be determined. If there is a significant difference between the atomic number and its surroundings, it is possible to identify the difference based on the difference.

After the first rough surface analysis for locating the approximate location of the inclusion is completed, the result of the rough surface analysis is subjected to data processing to specify which pixel has the inclusion. Then, a detailed surface analysis is performed on all of the pixels determined to have inclusions, and data collection is performed. In this case, if it is necessary to use WDS to analyze the individual pixels determined to have the inclusion, the X-ray generation position is shifted from the point on the Rowland circumference even if electron beam scanning is performed. The scanning magnification and the number of pixels are automatically determined so as to check whether the X-ray detection rate is not reduced due to the deviation and if the deviation does not occur, the surface analysis can be correctly performed by electron beam scanning. If the X-ray generation position deviates from a point on the circumference of the Roland, switch to the stage scanning in minute steps, or divide the area into a region where the X-ray detection rate can be ignored and specify the pixels specified by electron beam scanning. Perform an analysis.

As described above, the first rough analysis is generally performed by stage scanning. However, depending on the size of the inclusion, it is not always necessary to perform the stage analysis of the stage scanning from the beginning. If it is determined that the size is sufficiently small, or that sufficient good surface analysis information can be obtained by using an EDS or other backscattered electron detector without using WDS, first a rough surface analysis by beam scanning is performed. In some cases, the location of the inclusion is roughly determined, and then, in the area where the location of the inclusion is confirmed, the surface analysis is performed in detail by further increasing the scanning magnification. Conversely, if the size of the inclusion is sufficiently large, a coarse surface analysis is first performed by stage scanning, and then a more detailed surface analysis is performed by reducing the pixel length in a region where the presence of the inclusion is confirmed. In some cases, this is done.

Whether the surface analysis of a sample for inclusion analysis is performed using stage scanning or electron beam scanning as described above depends on the size of the target inclusion and the means of analysis. The analysis method is appropriately selected according to the mode of the inclusions to be analyzed.However, in the inclusion analysis using an electron probe microanalyzer, reflected electron detection is performed. In selecting which of the analyzers (R), WDS (W), and EDS (E) to use, a criterion as shown in the flowchart of FIG. 3 is usually used. That is, when the inclusions can be identified by the backscattered electrons, the inclusion analysis is performed using the backscattered electron detector. When the inclusions cannot be identified by the backscattered electrons and the concentration of the inclusions is several% or more, the EDS is used. When the concentration of inclusions is less than several%, inclusion analysis is usually performed using WDS.

In addition, the selection of a scanning method for analyzing inclusions by scanning a sample usually uses a criterion as shown in the flowchart of FIG. That is, when there is an area in the sample that cannot be covered by beam scanning, stage scanning (S) is used. When the sample is in an area that can be covered by beam scanning and WDS is not used as the analysis means, beam scanning is performed. (B) is used, and WDS
When the scanning magnification is less than 2000 times, for example, stage scanning is used, and when the scanning magnification is 2000 times or more, inclusion analysis is usually performed using beam scanning.

In the above embodiment, the method of analyzing inclusions in a sample is divided into two stages, a rough analysis is first performed to detect the presence of the inclusions, and then the area where the inclusions are present is analyzed in detail. However, the number of analysis steps is not limited to two,
The analysis may be performed at a stage. In this case as well, the analysis time can be significantly reduced, and more accurate inclusion analysis can be performed.

[0019]

As described above with reference to the embodiment, according to the first aspect of the present invention, a rough scan is first performed to roughly locate the inclusion, and then the presence of the inclusion is determined. Since the inclusion analysis is performed in at least two-stage analysis for performing a detailed surface analysis on the region, the analysis time can be significantly reduced. According to the second and third aspects of the present invention, accurate analysis of inclusions can be performed by using an appropriate analysis method or scanning method according to the aspect of the inclusions or the scanning magnification.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration example of an electron probe microanalyzer used for performing a method for analyzing inclusions in a sample according to the present invention.

FIG. 2 is a sample surface diagram for explaining a first rough analysis step and a detailed analysis step subsequent thereto in the embodiment of the sample inclusion analysis method according to the present invention.

FIG. 3 is a flowchart illustrating an example of a criterion in selecting an analysis unit.

FIG. 4 is a flowchart illustrating an example of a criterion in selecting a scanning method.

[Explanation of symbols]

 Reference Signs List 1 electron gun 2 Wehnelt 3 deflection coil 4 motor for driving X-ray spectroscope 5 X-ray spectroscopic crystal 6 X-ray detector 7 backscattered electron detector 8 secondary electron detector 9 EDS detector 10 analysis sample 11 sample stage 12 stage X Axis drive motor 13 Stage Y axis drive motor 14 Stage Z axis drive motor 15 Deflection coil controller 16 X-ray spectrometer drive motor controller 17 Stage drive motor controller 18 Secondary electron / reflected electron signal data acquisition device 19 WDSX-ray signal data acquisition device 20 EDSX-ray signal data acquisition device 21 Central processing unit 22 Large-capacity storage device 23 Joystick for stage manual drive

Claims (3)

[Claims] 1. A sample tester on which a sample is placed, an electron beam generator for irradiating the sample, a scanner for scanning the sample tester and the electron beam, and at least an X-ray signal and reflected electrons generated from the sample. In a method of analyzing inclusions in a sample using a sample analyzer having a means for measuring the intensity, an electron beam diameter is first set to about the size of one pixel, and scanning is performed over the entire sample in a rough manner. A coarse analysis step of locating the inclusions to be analyzed, and then reducing the diameter of the electron beam over the area where the inclusions are present so that the area can be covered by the coarse analysis step. Analyzing the inclusions in the sample. 2. Analyzing inclusions by selectively using an analysis method for measuring the intensity of an X-ray signal or a reflected electron according to whether the inclusions in the sample can be analyzed and identified and the concentration of the inclusions. The method for analyzing inclusions in a sample according to claim 1, characterized in that: 3. The method according to claim 1, wherein the analysis of the inclusion is performed by selectively using the sample stage scanning or the electron beam scanning according to the size of the inclusion in the sample, the analysis method of the inclusion, and the scanning magnification. The method for analyzing inclusions in a sample according to claim 1.