JPWO2015125604A1 - X-ray analyzer and computer program - Google Patents

Abstract

Provided are an X-ray analysis apparatus and a computer program capable of obtaining an X-ray intensity distribution with reduced influence due to the shape of a sample. The X-ray analyzer detects X-rays generated from each portion irradiated with the beam on the sample 5 by a plurality of X-ray detectors, and multiplies each by a weighting factor that simply increases with respect to the magnitude of the relative ratio. A weighted addition value obtained by adding a plurality of X-ray intensities is calculated. The X-ray analyzer generates an intensity distribution of X-rays generated from the sample 5 by using the calculated weighted addition value as the X-ray intensity at each portion on the sample 5. The weighted addition value of the X-ray intensity has a small contribution of the X-ray intensity attenuated by the influence of the shape of the sample 5, and is close to the X-ray intensity without attenuation. By setting the weighted addition value as the X-ray intensity at each portion of the sample 5, an X-ray intensity distribution in which the influence of the shape of the sample 5 is reduced can be obtained.

Description

  The present invention relates to an X-ray analyzer and a computer program for analyzing an intensity distribution of X-rays generated from a sample.

  X-ray analysis is an element contained in a sample from the spectrum of characteristic X-rays or fluorescent X-rays by irradiating the sample with radiation such as electron beams or X-rays, detecting X-rays generated from the sample with an X-ray detector. This is an analysis method for performing qualitative analysis or quantitative analysis. Further, by detecting X-rays from the sample while scanning the sample with a radiation beam, the intensity distribution of characteristic X-rays or fluorescent X-rays caused by a specific element can be examined. The intensity of the characteristic X-ray or fluorescent X-ray caused by a specific element corresponds to the amount of the specific element. Therefore, by examining the intensity distribution of the characteristic X-ray or fluorescent X-ray caused by the specific element, it is contained in the sample. It is possible to obtain a concentration distribution of a specific element. An X-ray analyzer using an electron beam may be incorporated in an electron microscope.

  By the way, when the sample has irregularities, X-rays generated from a part of the sample may be blocked by other parts of the sample before being detected by the X-ray detector. For this reason, the intensity | strength of the detected X-ray changes according to the shape of a sample. The intensity distribution of characteristic X-rays or fluorescent X-rays detected by the X-ray analyzer includes the influence of intensity change due to the shape of the sample, and an accurate element concentration distribution may not be obtained. In such a case, it was necessary to change the direction of observing the sample by a method such as rotating the sample.

  Thus, an X-ray analyzer that can observe a sample from a plurality of directions using a plurality of X-ray detectors has been put into practical use. Patent Document 1 discloses an X-ray analyzer using two X-ray detectors. A correction coefficient for correcting the added value of the X-ray intensities detected by the two X-ray detectors is obtained in advance from the intensity ratio of the X-rays incident on the two X-ray detectors. There is also disclosed a technique for reducing the influence of the shape of the sample by correcting the X-ray intensity using.

JP 2002-310957 A

  In an X-ray analyzer that can observe a sample from a plurality of directions, a plurality of X-ray intensity distributions can be obtained for one sample. Any X-ray intensity distribution includes the influence of intensity change due to the shape of the sample. If the observation direction is different, the intensity change due to the shape of the sample is also different, so the X-ray intensity distributions do not match. For this reason, none of the plurality of X-ray intensity distributions corresponds to an accurate element concentration distribution. Therefore, a method for deriving an element concentration distribution from a plurality of X-ray intensity distributions is required. A simple addition of a plurality of X-ray intensity distributions cannot remove the influence due to the shape of the sample, so a technique for reducing the influence due to the shape of the sample as disclosed in Patent Document 1 is required. However, in the method using two X-ray detectors, since X-rays can be detected only from two directions, the effect of reducing the influence due to the shape of the sample may be insufficient. When more X-ray detectors are used, there is a problem that the correction coefficient becomes too complex and analysis becomes difficult.

  The present invention has been made in view of such circumstances, and an object of the present invention is to correct the X-ray intensity detected by a plurality of X-ray detectors by a simple calculation method, thereby obtaining the shape of the sample. It is an object to provide an X-ray analysis apparatus and a computer program that can obtain an X-ray intensity distribution with reduced influence by the above.

  An X-ray analysis apparatus according to the present invention includes a scanning unit that scans a sample with a beam, and a plurality of X-ray detectors that detect X-rays generated from a portion irradiated with the beam by the scanning unit. In the X-ray analysis apparatus comprising: a plurality of X-ray intensities detected by the plurality of X-ray detectors for each of a plurality of portions irradiated with a beam on the sample by scanning by the scanning unit. A calculation unit that calculates a weighted addition value obtained by multiplying each X-ray intensity by a weighting factor that simply increases with respect to the magnitude of the relative ratio, and each portion irradiated with the beam on the sample, An intensity distribution generation unit that generates a corrected intensity distribution of X-rays by associating the weighted addition value calculated by the calculation unit with respect to the portion.

  The X-ray analysis apparatus according to the present invention is characterized in that the calculation unit is configured such that a value obtained by dividing each X-ray intensity by the sum of the plurality of X-ray intensities is used as the weighting factor.

  In the X-ray analysis apparatus according to the present invention, the calculation unit sets the weighting coefficient for the maximum X-ray intensity among the plurality of X-ray intensities to 1 and sets the weighting coefficient for other X-ray intensities to 0. It is configured.

  In the X-ray analysis apparatus according to the present invention, the calculation unit calculates an integral value of a specific energy range or wavelength range of X-rays detected by each X-ray detector over the plurality of X-ray detectors. A value obtained by dividing the value by the added value is configured as the weighting factor.

  In the X-ray analysis apparatus according to the present invention, the calculation unit calculates the weighted addition value for a plurality of X-ray intensities detected by the plurality of X-ray detectors for X-rays caused by a specific element. The intensity distribution generation unit is configured to generate an X-ray intensity distribution caused by the specific element.

  An X-ray analyzer according to the present invention includes an irradiation unit that irradiates a sample with a beam, and a plurality of X-ray detectors that detect X-rays generated from the portion irradiated with the beam on the sample. The weights obtained by multiplying the X-ray intensities obtained by multiplying the X-ray intensities detected by the plurality of X-ray detectors by a weighting factor that simply increases with respect to the relative ratio of the X-ray intensities. A calculation unit that calculates an added value, and a spectrum generation unit that generates a spectrum using the weighted addition value calculated by the calculation unit for each of X-ray energy or wavelength as an X-ray intensity. .

  The computer program according to the present invention is a computer program for causing a computer to analyze the results of detecting X-rays generated from a sample scanned with a beam by a plurality of X-ray detectors. For each of the plurality of portions, a plurality of X-ray intensities detected by the plurality of X-ray detectors are set to each X-ray intensity with a weight coefficient that simply increases with respect to the relative ratio of each X-ray intensity. X-ray intensity distribution by associating a weighted addition value calculated for each part with a step of causing the computer to calculate a weighted addition value obtained by multiplication and adding each part irradiated with the beam on the sample Generating.

  In the present invention, an X-ray analyzer detects X-rays generated from a sample irradiated with a beam with a plurality of X-ray detectors, and sets a weighting factor that simply increases with respect to the relative ratio of X-ray intensity. A weighted addition value obtained by adding a plurality of X-ray intensities after multiplication is calculated. The X-ray analyzer generates an X-ray intensity distribution using the weighted addition value as the X-ray intensity at each portion on the sample. The weighted addition value of the X-ray intensity has an effect that the contribution of a relatively large intensity among the X-ray intensities detected by a plurality of X-ray detectors becomes large, and the X-ray attenuates according to the shape of the sample. Is reduced.

  In the present invention, the X-ray analyzer calculates a weighted addition value of X-ray intensity using a value obtained by dividing each X-ray intensity by the sum of X-ray intensities detected by a plurality of X-ray detectors as a weighting factor. . As the X-ray intensity at each part of the sample, an X-ray intensity with a large contribution of a relatively large intensity among the X-ray intensities detected by a plurality of X-ray detectors is generated. Is done.

  In the present invention, the X-ray analyzer sets the weighting coefficient for the maximum X-ray intensity among the X-ray intensities detected by the plurality of X-ray detectors to 1, and sets the weighting coefficient for the other X-ray intensities to 0. A weighted addition value of the X-ray intensity is calculated. Thereby, the X-ray analyzer sets the maximum value among the X-ray intensities detected by the plurality of X-ray detectors as the intensity of the characteristic X-ray generated from the sample.

  In the present invention, the X-ray analyzing apparatus divides each integral value by a value obtained by adding the integral values of the X-rays detected by the respective X-ray detectors over a plurality of X-ray detectors. Get. Integration is performed over a specific energy or wavelength range. The integration range is, for example, a range of all energy or all wavelengths in which X-rays can be detected, or a range including energy or wavelength of characteristic X-rays caused by a specific element. By calculating the weighted addition value of the X-ray intensity using this weighting factor, the contribution of a relatively large intensity among the X-ray intensities detected by a plurality of X-ray detectors is large, and the intensity is relatively small. X-ray intensity with a small contribution can be obtained.

  In the present invention, the X-ray analyzer generates a characteristic X-ray intensity distribution corresponding to a specific element. Thereby, the concentration distribution on the sample of a specific element is obtained.

  In the present invention, the X-ray analyzer generates a spectrum composed of a weighted addition value of the calculated X-ray intensity. Thereby, the X-ray spectrum which reduced the influence by the shape of a sample is obtained.

  In the present invention, the X-ray analyzer can easily generate the intensity distribution of characteristic X-rays in which the influence due to the shape of the sample is reduced. For this reason, the X-ray analyzer can obtain an accurate concentration distribution of elements contained in the sample, and the present invention has excellent effects.

1 is a block diagram showing a configuration of an X-ray analysis apparatus according to Embodiment 1. FIG. It is a typical top view of a X-ray detection part. It is a block diagram which shows the internal structure of a control apparatus. It is a schematic diagram which shows the example of intensity distribution of the characteristic X-ray which each X-ray detector detected. It is a flowchart which shows the procedure of the process which a control apparatus performs. It is a schematic diagram which shows the example of intensity distribution of the characteristic X-ray produced | generated by S3. FIG. 10 is a block diagram showing a configuration of an X-ray analyzer according to a fifth embodiment.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of the X-ray analyzer according to the first embodiment. The X-ray analyzer includes an electron gun 41 that irradiates a sample 5 with an electron beam (beam), an electron lens system 42, and a sample stage 43 on which the sample 5 is placed. The electron lens system 42 includes a scanning coil that changes the direction of the electron beam. The electron gun 41 and the electron lens system 42 correspond to the scanning unit in the present invention. The electron gun 41 and the electron lens system 42 are connected to a control device 3 that controls the entire X-ray analyzer.

  The X-ray detection unit 1 is disposed between the electron lens system 42 and the sample stage 43. The X-ray detector 1 is formed in a shape provided with a hole for passing an electron beam. FIG. 1 shows a cross section of the X-ray detector 1. The X-ray detector 1 includes a plurality of X-ray detectors each using an SDD (Silicon Drift Detector). FIG. 2 is a schematic plan view of the X-ray detection unit 1. In the X-ray detection unit 1, a plurality of X-ray detectors 11, 12, 13, and 14 are mounted on a substrate on which a hole 15 is formed, and the X-ray detectors 11, 12, 13, and 14 are disposed surrounding the hole 15. It becomes the composition. The X-ray detection unit 1 is disposed at a position where the electron beam passes through the hole 15, and the X-ray incident surface intersects the electron beam axis. The X-ray detection unit 1 is attached with a cooling mechanism (not shown) such as a Peltier element. In a state where the sample 5 is placed on the sample stage 43, the X-ray detection unit 1 is disposed in front of the surface of the sample 5 that is irradiated with the electron beam. In accordance with a control signal from the control device 3, the electron gun 41 emits an electron beam, the electron lens system 42 determines the direction of the electron beam, and the electron beam passes through the hole 15 of the X-ray detection unit 1 on the sample table 43. The sample 5 is irradiated. A characteristic X-ray is generated in the portion irradiated with the electron beam on the sample 5. Characteristic X-rays are detected by X-ray detectors 11, 12, 13, and 14 included in the X-ray detector 1. That is, characteristic X-rays simultaneously generated from the same portion on the sample 5 are detected independently by a plurality of X-ray detectors. In FIG. 1, the electron beam is indicated by a solid line arrow, and the characteristic X-ray is indicated by a broken line arrow. The X-ray detectors 11, 12, 13, and 14 output a signal proportional to the detected characteristic X-ray energy. Of the configuration of the X-ray analyzer, at least the electron gun 41, the electron lens system 42, the X-ray detector 1 and the sample stage 43 are housed in a vacuum box (not shown). The vacuum box is made of a material that shields electron beams and X-rays, and the inside of the vacuum box is kept in a vacuum during the operation of the X-ray analyzer.

  Each of the X-ray detectors 11, 12, 13, and 14 is connected to a signal processing unit 2 that processes the output signal. The signal processing unit 2 receives signals output from the X-ray detectors 11, 12, 13, and 14, counts the signals by value, and associates the characteristic X-ray energy indicated by the signal value with the count number. Processing to acquire an X-ray spectrum is performed. The count number associated with a certain energy is the intensity of characteristic X-rays having that energy. The signal processing unit 2 is connected to the control device 3. The electron beam scans the sample 5 by the electron lens system 42 sequentially changing the direction of the electron beam. As the electron beam scans the sample 5, the electron beam is sequentially irradiated to each portion in the scanning region on the sample 5. As the electron beam scans the sample 5, the characteristic X-rays generated from the portion irradiated with the electron beam on the sample 5 are sequentially detected by the X-ray detectors 11, 12, 13, and 14. The signal processing unit 2 sequentially generates a spectrum of characteristic X-rays generated at a plurality of portions irradiated with the electron beam on the sample 5 by sequentially performing signal processing. The signal processing unit 2 individually generates a spectrum of characteristic X-rays detected by the X-ray detectors 11, 12, 13, and 14. That is, a plurality of spectra of characteristic X-rays are generated for each of a plurality of portions irradiated with an electron beam on the sample 5. The signal processing unit 2 sequentially outputs the generated characteristic X-ray spectrum data to the control device 3.

  FIG. 3 is a block diagram showing an internal configuration of the control device 3. The control device 3 is configured using a computer such as a personal computer. The control device 3 includes a CPU (Central Processing Unit) 31 that performs calculations, a RAM (Random Access Memory) 32 that stores temporary data generated along with the calculations, and a drive that reads information from a recording medium 6 such as an optical disk. Unit 33 and a non-volatile storage unit 34 such as a hard disk. Further, the control device 3 includes an operation unit 35 such as a keyboard or a mouse that accepts a user operation, a display unit 36 such as a liquid crystal display, and an interface unit 37. An electron gun 41, an electron lens system 42, and the signal processing unit 2 are connected to the interface unit 37. The CPU 31 causes the drive unit 33 to read the computer program 61 recorded on the recording medium 6 and stores the read computer program 61 in the storage unit 34. The computer program 61 is loaded from the storage unit 34 to the RAM 32 as necessary, and the CPU 31 executes processing necessary for the X-ray analyzer according to the loaded computer program 61. The computer program 61 may be downloaded from outside the control device 3. The control device 3 receives the characteristic X-ray spectrum data output from the signal processing unit 2 by the interface unit 37, and associates the position of the portion irradiated with the electron beam on the sample 5 with the characteristic X-ray spectrum. Data is stored in the storage unit 34. Further, the control device 3 controls the operation of the electron lens system 42 connected to the interface unit 37.

  When the scanning of the sample 5 by the electron beam is completed, the control device 3 associates the characteristic X-ray spectrum data detected by the X-ray detectors 11, 12, 13, and 14 with each portion on the sample 5. Is stored in the storage unit 34. It is also possible to obtain the intensity distribution on the sample 5 of the characteristic X-rays detected by the X-ray detectors 11, 12, 13, and 14 from the stored data. However, the characteristic X-ray intensity detected by each X-ray detector is influenced by the shape of the sample 5. For this reason, the intensity distribution of characteristic X-rays detected by individual X-ray detectors does not correspond to the concentration distribution of elements in the sample 5.

  The intensity of characteristic X-rays is also affected by the detection efficiency of each X-ray detector. The detection efficiencies of the respective X-ray detectors are generally different from each other due to various factors. Factors that cause different detection efficiencies include, for example, the difference in detection solid angle determined from the effective area of the X-ray detector, the distance from the sample to the X-ray detector, and the incident angle of the characteristic X-ray from the sample to the X-ray detector. There is. Also, for example, the difference in detection sensitivity of the X-ray detector due to the difference in the material and thickness of the X-ray entrance surface of the X-ray detector or the X-ray incident surface of the X-ray detector. For example, it is a difference in dead time due to a difference in signal processing speed or time constant. However, since these factors are known before the measurement of characteristic X-rays, the difference in detection efficiency of each X-ray detector can be corrected with a correction coefficient. The correction coefficient is predetermined theoretically or experimentally and is stored in the storage unit 34. The control device 3 stores, in the storage unit 34, characteristic X-ray spectrum data in which the influence of the detection efficiency of each X-ray detector is corrected.

  FIG. 4 is a schematic diagram showing an example of intensity distribution of characteristic X-rays detected by individual X-ray detectors. It is assumed that the sample 5 has a spherical shape, and characteristic X-rays having the same intensity are generated from each part on the sample 5. FIG. 4A shows the intensity distribution of characteristic X-rays detected by the X-ray detector 11. The dark hatched portions in FIGS. 4A to 4D indicate that the intensity of the detected characteristic X-ray is small. As shown in FIGS. 1 and 2, the X-ray detector 11 detects characteristic X-rays from the sample 5 at a position obliquely above the sample 5. The intensity of the characteristic X-rays from the portions hidden on the shadow of other portions when viewed from the X-ray detector 11 in each portion on the sample 5 is attenuated. In the plan view shown in FIG. 2, since the sample 5 is at the position of the hole 15 and the X-ray detector 11 is at the upper left position with respect to the sample 5, the lower right portion of the spherical sample 5 is detected by X-ray detection. Hidden behind other parts as seen from the vessel 11. Therefore, as shown in FIG. 4A, in the intensity distribution of the characteristic X-ray detected by the X-ray detector 11, the characteristic X-ray intensity in the lower right part is smaller than in the other parts.

  FIG. 4B shows the intensity distribution of characteristic X-rays detected by the X-ray detector 12. On the plan view shown in FIG. 2, the X-ray detector 12 is located at the lower left position with respect to the sample 5, so as shown in FIG. 4B, in the intensity distribution of the characteristic X-ray detected by the X-ray detector 12, The characteristic X-ray intensity in the upper right part is smaller than in other parts. FIG. 4C shows the characteristic X-ray intensity distribution detected by the X-ray detector 13. On the plan view shown in FIG. 2, the X-ray detector 13 is located at the upper right position with respect to the sample 5, so as shown in FIG. 4C, the intensity distribution of the characteristic X-ray detected by the X-ray detector 13 is The characteristic X-ray intensity in the lower left part is smaller than in other parts. FIG. 4D shows the intensity distribution of characteristic X-rays detected by the X-ray detector 14. In the plan view shown in FIG. 2, the X-ray detector 14 is located at the lower right position with respect to the sample 5. Therefore, as shown in FIG. 4D, the intensity distribution of the characteristic X-ray detected by the X-ray detector 14 is The characteristic X-ray intensity in the upper left part is smaller than in the other parts.

The control device 3 performs a calculation for correcting the intensity distribution of the characteristic X-ray so as to remove the influence due to the shape of the sample 5. The position of each part irradiated with the electron beam on the sample 5 is indicated by (x, y). Let N be the number of X-ray detectors, and let I _i (x, y) be the intensity at which the characteristic X-ray generated at the position (x, y) is detected by the i-th X-ray detector. I _i (x, y) is a count number of characteristic X-rays, and is obtained for each energy. In the example shown in the present embodiment, N = 4. The control device 3 calculates a weighted addition value I (x, y) of characteristic X-ray intensities detected by a plurality of X-ray detectors by calculation according to the following equation (1).

In the equation (1), w _i (x, y) is a weighting factor for each X-ray detector. The weighting factor w _i (x, y) is the magnitude of the relative ratio of the detected characteristic X-ray intensity for each of a plurality of X-ray detectors that have detected the characteristic X-ray generated at the position (x, y). It is determined to increase simply. Specifically, the weight coefficient w _i (x, y) is expressed by the following equation (2).

As expressed by the equation (2), w _i (x, y) is a sum of intensities obtained by detecting a characteristic X-ray generated at the position (x, y) with a plurality of X-ray detectors. This is a value obtained by dividing the intensity of the characteristic X-ray detected by the line detector. By calculating I (x, y) using the equations (1) and (2), I (x having a relatively large intensity among the intensities of characteristic X-rays detected by a plurality of X-ray detectors. , Y) is increased, and the influence on relatively small intensity I (x, y) is decreased. Among the plurality of characteristic X-ray intensities, a relatively small intensity is attenuated by the influence of the shape of the sample 5, and a relatively large intensity is close to the intensity of the characteristic X-rays without attenuation. Since the weighted addition value I (x, y) of the characteristic X-ray intensity measured by a plurality of X-ray detectors has a large contribution of relatively large intensity and a small contribution of small intensity, It is the characteristic X-ray intensity in which the influence of the shape is reduced.

  FIG. 5 is a flowchart showing a procedure of processing executed by the control device 3. The CPU 31 loads the computer program 61 from the storage unit 34 to the RAM 32 and executes the following processing according to the loaded computer program 61. The control device 3 controls the electron gun 41 and the electron lens system 42 and scans the sample 5 with the electron beam, while detecting the characteristic X-ray spectrum data detected by the X-ray detectors 11, 12, 13, and 14. Are associated with each part on the sample 5 and stored in the storage unit 34 (S1). The CPU 31 reads out the characteristic X-ray spectrum data stored in the storage unit 34 to the RAM 32 and uses the equations (1) and (2) to detect the characteristic X detected by the X-ray detectors 11, 12, 13, and 14. The weighted addition value I (x, y) of the line intensity is calculated (S2). In S2, the CPU 31 calculates a weighted addition value I (x, y) of the characteristic X-ray intensity for each energy included in the spectrum of the characteristic X-ray. The CPU 31 associates the characteristic X-ray energy with the calculated I (x, y), and generates a characteristic X-ray spectrum in which the influence of the shape of the sample 5 is reduced. In S <b> 2, the CPU 31 weights the characteristic X-ray intensity detected by the X-ray detectors 11, 12, 13, and 14 for each portion irradiated with the electron beam on the sample 5. y) is calculated to generate a characteristic X-ray spectrum in which the influence of the shape of the sample 5 is reduced.

  Next, the CPU 31 generates the intensity distribution of the characteristic X-rays generated on the sample 5 by using the weighted addition value I (x, y) of the characteristic X-ray intensity as the intensity of the characteristic X-rays generated from the sample 5. (S3). Specifically, the CPU 31 associates the position of each portion irradiated with the electron beam on the sample 5 with the weighted addition value I (x, y) of the calculated characteristic X-ray intensity to thereby obtain the characteristic X-ray. Generate an intensity distribution of In S <b> 3, the CPU 31 associates the position of each portion on the sample 5 with the spectrum of the characteristic X-ray to generate a spectral distribution of the characteristic X-ray. Further, the CPU 31 associates the position of each portion on the sample 5 with I (x, y) of the specific energy included in the spectrum of the characteristic X-ray, and calculates the intensity distribution of the characteristic X-ray having the specific energy. It can also be generated. The storage unit 34 stores data in which a specific element and characteristic X-ray energy caused by the element are associated with each other, and the CPU 31 calculates the intensity distribution of the characteristic X-ray having energy corresponding to the specific element. It may be generated. The intensity distribution of the characteristic X-ray obtained in S3 is an intensity distribution corrected so as to reduce the influence of the shape of the sample 5. The CPU 31 calculates the element concentration from the energy I (x, y) corresponding to the specific element, and generates an element concentration distribution in which the position of each part on the sample 5 is associated with the concentration of the specific element. May be. Further, the CPU 31 calculates the weighted addition value I (x, y) of the characteristic X-ray intensity only for the energy of the characteristic X-ray caused by the specific element, and the intensity distribution of the characteristic X-ray caused by the specific element Alternatively, a concentration distribution of a specific element may be generated. The CPU 31 can also display an image of the generated characteristic X-ray intensity distribution or element concentration distribution on the display unit 36. The CPU 31 stores data representing the intensity distribution or element concentration distribution of characteristic X-rays in the storage unit 34 and ends the process.

  As described above in detail, in the present embodiment, the X-ray analyzer detects characteristic X-rays generated from each part of the sample 5 irradiated with the electron beam by the X-ray detectors 11, 12, 13, and 14. The weighted addition value I (x, y) of the characteristic X-ray intensity is calculated. The X-ray analyzer generates the intensity distribution of the characteristic X-rays generated from the sample 5 by using the calculated weighted addition value I (x, y) as the characteristic X-ray intensity in each part of the sample 5. The weighted addition value I (x, y) of the characteristic X-ray intensity greatly contributes to a relatively large intensity among the characteristic X-ray intensities detected by a plurality of X-ray detectors. The reason why the intensity of the characteristic X-rays generated from the same part of the sample 5 detected by the plurality of X-ray detectors is different is that the attenuation of the characteristic X-rays due to the influence of the shape of the sample 5 differs depending on the position of the X-ray detector. is there. Since the relatively large intensity is close to the intensity of the characteristic X-rays without attenuation, the weighted addition value I (x, y) of the characteristic X-ray intensity has a large contribution of relatively large intensity and a small contribution of relatively small intensity. ) Is the characteristic X-ray intensity in which the influence of the shape of the sample 5 is reduced. The X-ray analyzer generates a characteristic X-ray intensity distribution generated from the sample 5 using the weighted addition value I (x, y) as the characteristic X-ray intensity, thereby reducing the influence of the shape of the sample 5 An X-ray intensity distribution can be generated.

  FIG. 6 is a schematic diagram illustrating an example of the intensity distribution of the characteristic X-ray generated in S3. FIG. 6 shows the intensity distribution of characteristic X-rays generated by reducing the influence of the shape of the sample 5 from the characteristic X-ray detection results shown in FIGS. It is shown that there is no portion where the intensity of the characteristic X-ray is reduced due to the shape of the sample 5, and the characteristic X-ray is generated from each part on the sample 5 with a uniform intensity.

  The calculation method of the weighted addition value I (x, y) of the characteristic X-ray intensity according to the present embodiment is a simple calculation method, and may be complicated even if the number of X-ray detectors increases. No. Therefore, even when the number of X-ray detectors is large, the X-ray analyzer can easily obtain an X-ray intensity distribution in which the influence of the sample shape is reduced. The X-ray analysis apparatus can obtain an X-ray intensity distribution in which the influence of the shape of the sample is sufficiently reduced by using a large number of X-ray detectors.

  In the intensity distribution of the characteristic X-ray generated by the X-ray analyzer, the influence of the shape of the sample 5 is small with respect to the difference in the characteristic X-ray intensity due to the difference in position on the sample 5. For this reason, this intensity distribution reflects the concentration distribution on the sample 5 of the element causing the characteristic X-rays. Therefore, the X-ray analysis apparatus can obtain an accurate concentration distribution of elements contained in the sample 5.

  Note that the X-ray analysis apparatus is not limited to the form in which the image of the characteristic X-ray intensity distribution or the element concentration distribution is displayed on the display unit 36, but may be a form in which an image is displayed on an external display device. Further, the signal processing unit 2 may be configured to execute a part of the processing of the control device 3 described in the present embodiment, and the control device 3 may include the signal processing unit 2 described in the present embodiment. The form which performs a part of process may be sufficient. Further, the X-ray analysis apparatus may have a form in which the signal processing unit 2 and the control device 3 are integrated. Further, the X-ray analyzer may be in a form incorporated in an SEM (scanning electron microscope) or TEM (transmission electron microscope). In this embodiment, the X-ray analyzer includes a detector for detecting electrons such as reflected electrons, secondary electrons, or transmitted electrons, and a signal processing unit for processing signals from the detector, for SEM or TEM. It is done.

(Embodiment 2)
The configuration of the X-ray analyzer according to the second embodiment is the same as that of the first embodiment. In the second embodiment, the X-ray analyzer calculates the weighted addition value I (x, y) of the characteristic X-ray intensity by a method different from that in the first embodiment.

As in the first embodiment, the X-ray analyzer irradiates the sample 5 with an electron beam and detects characteristic X-rays generated from each part of the sample 5 with the X-ray detectors 11, 12, 13, and 14. A spectrum of characteristic X-rays is generated by the signal processing unit 2. The control device 3 executes the processes of S1 to S3 as in the first embodiment. Among these processes, in S2, the CPU 31 performs calculation by another method without using the equation (2) in order to calculate the weighting coefficient w _i (x, y). The CPU 31 sets the weight coefficient for the maximum intensity to 1 among the intensities I _i (x, y) obtained by detecting the characteristic X-rays generated at the position (x, y) on the sample 5 with a plurality of X-ray detectors. The weighting factors for other X-ray intensities are set to zero. That is, assuming that the maximum value of N I _i (x, y) is I _j (x, y), w _j (x, y) = 1, i ≠ j w _i (x, y) = 0. The weighted addition value I (x, y) of the characteristic X-ray intensity is I (x, y) = I _j (x, y) from the equation (1). In S2, the CPU 31 calculates the weighted addition value I (x, y) of the characteristic X-ray intensity in this way.

  As described above, in the present embodiment, the X-ray analyzer is a characteristic generated from the sample 5 with the maximum value of the characteristic X-ray intensities detected by the X-ray detectors 11, 12, 13, and 14. The intensity distribution of the characteristic X-ray generated on the sample 5 is generated with the X-ray intensity. The maximum value of the characteristic X-ray intensities detected by the plurality of X-ray detectors has the minimum attenuation of the characteristic X-ray due to the influence of the shape of the sample 5. By setting this maximum value as the characteristic X-ray intensity, the X-ray analyzer can obtain characteristic X-ray intensity in which the influence of the shape of the sample 5 is reduced as much as possible. The X-ray analyzer can generate an intensity distribution of the characteristic X-rays obtained, thereby generating an intensity distribution of the characteristic X-rays in which the influence of the shape of the sample 5 is reduced as much as possible. In addition, the X-ray analyzer can obtain an accurate concentration distribution of elements contained in the sample 5 as in the first embodiment.

  In the present embodiment, the characteristic X-ray intensity detected by a plurality of X-ray detectors is not actually added. Since the characteristic X-ray intensity is not smoothed by the addition, the SN ratio of the characteristic X-ray intensity distribution and the element concentration distribution is deteriorated as compared with the first embodiment. However, since addition, division, and multiplication of the characteristic X-ray intensity necessary for the first embodiment are unnecessary, the calculation load of the control device 3 is reduced in this embodiment. Therefore, in this embodiment, the X-ray analysis apparatus can be realized with smaller calculation resources.

  In the present embodiment, an example is shown in which only the maximum value is used among the intensity of characteristic X-rays detected by a plurality of X-ray detectors, but the X-ray analyzer has a relatively large value. A form using a plurality of characteristic X-ray intensities may be used. For example, the X-ray analysis apparatus sets a weighting factor for a predetermined number of characteristic X-ray intensities having relatively large values among characteristic X-ray intensities detected by a plurality of X-ray detectors as a positive value, and other characteristics. The weighted addition value I (x, y) of the characteristic X-ray intensity may be calculated by setting the weighting coefficient for the X-ray intensity to 0.

(Embodiment 3)
The configuration of the X-ray analyzer according to the third embodiment is the same as that of the first embodiment. As in the first embodiment, the X-ray analyzer irradiates the sample 5 with an electron beam and detects characteristic X-rays generated from each part of the sample 5 with the X-ray detectors 11, 12, 13, and 14. A spectrum of characteristic X-rays is generated by the signal processing unit 2. The control device 3 executes the processes of S1 to S3 as in the first embodiment. Among these processes, in S2, the CPU 31 does not use the equation (2) to calculate the weighting factor w _i (x, y), but instead uses the weighting factor w _i ( x, y) is used.

S _i (x, y) in the equation (3) is represented by the following equation (4).

In equation (4), E is the characteristic X-ray energy, Emin is the lower limit value of the characteristic X-ray energy that can be detected by the X-ray detectors 11, 12, 13, and 14, and Emax is the upper limit value. is there. S _i (x, y) is the sum of the counts over the entire energy of the characteristic X-ray. In S2, the CPU 31 calculates the weighting coefficient w _i (x, y) using the equations (3) and (4), and uses the equation (1) to add the weighted addition value I (x , Y). In S3, the CPU 31 performs the same process as in the first embodiment, and generates a characteristic X-ray intensity distribution. In addition, the X-ray analyzer can obtain an accurate concentration distribution of elements contained in the sample 5 as in the first embodiment. Also in the present embodiment, the X-ray analyzer can generate a characteristic X-ray intensity distribution in which the influence of the shape of the sample 5 is reduced as much as possible. A concentration distribution can be obtained.

As described above, in the present embodiment, the weight coefficient w _i (x, y) is calculated from the sum of the count numbers over the entire energy of the characteristic X-ray. As a result, the weighting coefficient w _i (x, y) is the same for any energy. When calculating the weighted addition value I (x, y) of the characteristic X-ray intensity, it is not necessary to calculate the weight coefficient w _i (x, y) for each energy included in the spectrum of the characteristic X-ray. The amount of calculation required is reduced. In addition, the variation of the weighted addition value I (x, y) of the characteristic X-ray intensity is smaller than when the weighting coefficient is calculated for each energy, and the SN distribution of the characteristic X-ray intensity distribution and the element concentration distribution is reduced. The ratio is improved.

(Embodiment 4)
The configuration of the X-ray analyzer according to the fourth embodiment is the same as that of the first embodiment. In the first to third embodiments, the X-ray count number having a certain energy is set as the X-ray intensity. However, in the fourth embodiment, the X-ray analyzer sets the X-ray count number in a specific energy range. The integrated value is taken as the X-ray intensity.

As in the first embodiment, the X-ray analyzer irradiates the sample 5 with an electron beam and detects characteristic X-rays generated from each part of the sample 5 with the X-ray detectors 11, 12, 13, and 14. A spectrum of characteristic X-rays is generated by the signal processing unit 2. Let R _i (x, y) be the intensity at which the characteristic X-ray generated at the position (x, y) is detected by the i-th X-ray detector. R _i (x, y) is a value obtained by integrating the count number of characteristic X-rays within a specific energy range. R _i (x, y) is expressed by the following equation (5).

  The integration range of the equation (5) is a specific energy range including the characteristic X-ray energy caused by the specific element. E1 is a lower limit value of energy included in a specific energy range, and E2 is an upper limit value. The energy range corresponding to a specific element is a so-called ROI (region of interest). In the spectrum of characteristic X-rays, a peak corresponding to a specific element is included in the range of ROI. A plurality of ROIs corresponding to a specific element can be set, and the integration range of equation (5) may include a plurality of ROIs.

  The control device 3 executes the processes of S1 to S3 as in the first embodiment. Among these processes, in S2, the control device 3 calculates a weighted addition value R (x, y) of characteristic X-ray intensities detected by a plurality of X-ray detectors by calculation according to the following equation (6). calculate.

The weighting factor w _i (x, y) for each X-ray detector in the present embodiment is expressed by the following equation (7).

The CPU 31 calculates the weighting coefficient w _i (x, y) using the equations (5) and (7), and uses the equation (6) to add the weighted addition value R (x, y) of the characteristic X-ray intensity. Calculate When there are a plurality of specific elements for which the element concentration distribution is to be generated, the CPU 31 calculates the weighting coefficient w _i (x, y) for the ROI of each element, and the weighted addition value R of the characteristic X-ray intensity. Calculate (x, y). In S3, the CPU 31 performs the same process as in the first embodiment, and generates a characteristic X-ray intensity distribution. In addition, the X-ray analyzer can obtain an accurate concentration distribution of elements contained in the sample 5 as in the first embodiment. Also in the present embodiment, the X-ray analyzer can generate a characteristic X-ray intensity distribution in which the influence of the shape of the sample 5 is reduced as much as possible. A concentration distribution can be obtained.

  As described above, in this embodiment, the value obtained by integrating the count number of characteristic X-rays within the ROI range corresponding to a specific element is set as the intensity of characteristic X-rays attributed to the specific element, and weighted addition is performed. The value R (x, y) is calculated. Since the value obtained by integrating the count number within the ROI range is larger than the count number for each energy, the variation of the weighted addition value R (x, y) of the characteristic X-ray intensity is reduced. The SN ratio of the characteristic X-ray intensity distribution and the element concentration distribution is improved. Further, the weighted addition value of the weighting coefficient and the characteristic X-ray intensity may be calculated for the ROI corresponding to each element, and it is not necessary to calculate each energy one by one, so that the necessary calculation amount is reduced.

Note that the CPU 31 may calculate the weighting coefficient w _i (x, y) using the equation (3) instead of the equation (7) in S2. In this case, the weighting factors w _i (x, y) are the same, and the required calculation amount is reduced. Further, in S2, the CPU 31 sets the integration range when calculating R _i (x, y) for use in the calculation of the expression (7) as a range including a plurality of ROIs corresponding to a plurality of elements. The coefficient w _i (x, y) may be calculated. In this case, the weighting coefficients w _i (x, y) are the same, and the elements other than the plurality of elements for which the element concentration distribution should be generated are compared with the case where the weighting coefficients are calculated using the equation (3). Can be reduced.

(Embodiment 5)
FIG. 7 is a block diagram showing the configuration of the X-ray analyzer according to the fifth embodiment. The X-ray analyzer does not include the electron gun 41 and the electron lens system 42 but includes an X-ray source 44 and a drive unit 45 that moves the sample stage 43 in the horizontal direction. The X-ray source 44 is configured using an X-ray tube. The X-ray source 44 irradiates the sample 5 on the sample stage 43 with an X-ray beam. The X-ray detection unit 1 is disposed between the X-ray source 44 and the sample stage 43. The configuration of the X-ray detection unit 1 is the same as that of the first embodiment. X-ray detectors 11, 12, 13, and 14 included in the X-ray detection unit 1 detect fluorescent X-rays generated from the sample 5 by irradiation with an X-ray beam. The signal processing unit 2 acquires a spectrum of fluorescent X-rays based on signals output from the X-ray detectors 11, 12, 13, and 14. The control device 3 controls the operation of the driving unit 45 to move the sample stage 43 in the horizontal plane direction, and irradiate the sample 5 on the moved sample stage 43 with the X-ray beam, whereby the sample 5 is irradiated with the X-ray beam. The process of scanning is executed. The X-ray source 44 and the drive unit 45 correspond to the scanning unit in the present invention. The signal processing unit 2 generates a plurality of spectra of fluorescent X-rays for each portion on the sample 5 irradiated with the X-ray boom.

  Note that the X-ray analyzer may have a configuration including an X-ray optical system (not shown) for guiding the X-ray beam to the sample 5. In addition, the X-ray analyzer may be in a form including an X-ray source other than the X-ray source 44 using an X-ray tube, such as an X-ray source using an accelerator.

  The control device 3 executes the same processing as S1 to S3 as in the first embodiment. That is, the control device 3 stores the fluorescent X-ray spectrum data detected by the X-ray detectors 11, 12, 13, and 14 in the storage unit 34 in association with each part on the sample 5. The CPU 31 calculates a weighted addition value of the fluorescent X-ray intensity detected by the X-ray detectors 11, 12, 13, and 14. At this time, the CPU 31 calculates the weighted addition value I (x, y) of the fluorescent X-ray intensity by the same calculation method as in the first to third embodiments, or the fluorescence by the same calculation method as in the fourth embodiment. A weighted addition value R (x, y) of the X-ray intensity is calculated. Next, the CPU 31 generates an intensity distribution of the fluorescent X-rays generated on the sample 5 using the weighted addition value of the fluorescent X-ray intensity as the intensity of the fluorescent X-rays generated from the sample 5. Specifically, the CPU 31 generates an intensity distribution of fluorescent X-rays by associating the position of each portion irradiated with the X-ray beam on the sample 5 with a weighted addition value of the calculated fluorescent X-ray intensity. To do. At this time, the CPU 31 can generate a spectral distribution of fluorescent X-rays. The CPU 31 can also generate an intensity distribution of fluorescent X-rays having specific energy. The storage unit 34 stores data in which a specific element is associated with fluorescent X-ray energy caused by the element, and the CPU 31 generates fluorescent X-ray intensity having energy corresponding to the specific element. May be. Further, the CPU 31 may calculate the element concentration from the fluorescent X-ray intensity having energy corresponding to the specific element, and generate the concentration distribution of the specific element included in the sample 5. The CPU 31 can also display an image of the generated fluorescent X-ray intensity distribution or element concentration distribution on the display unit 36. The CPU 31 stores data representing the fluorescent X-ray intensity distribution or element concentration distribution in the storage unit 34.

  In the present embodiment, the X-ray analyzer can obtain the fluorescent X-ray intensity with the influence of the shape of the sample 5 reduced as in the first to fourth embodiments. Similarly, the X-ray analyzer can generate an intensity distribution of fluorescent X-rays that is less influenced by the shape of the sample 5 by generating an intensity distribution of the obtained fluorescent X-rays. Similarly, the X-ray analyzer can obtain an accurate concentration distribution of elements contained in the sample 5.

  In the above first to fifth embodiments, an X-ray intensity distribution is generated after generating X-ray spectra detected by a plurality of X-ray detectors. An X-ray intensity distribution may be generated without generating an X-ray spectrum. For example, the X-ray analyzer may be configured to generate an intensity distribution of only X-rays having specific energy. In the first to fifth embodiments, the X-ray intensity weighted addition value is calculated after the scanning of the sample 5 is completed. 5 may be a form in which a weighted addition value of the intensity of X-rays generated from each point on 5 is calculated. Further, as the beam in the present invention, the embodiment using the electron beam is shown in the first to fourth embodiments, and the embodiment using the X-ray beam is shown in the fifth embodiment. Energy rays may be used. For example, the X-ray analyzer may be configured to irradiate the sample 5 with a beam of charged particles.

  In addition, the X-ray analysis apparatus can determine the weighting coefficient by a method other than the methods shown in the first to fifth embodiments. The weighting factor is determined so as to simply increase with respect to the magnitude of the relative ratio of the detected characteristic X-ray intensity for each of the plurality of X-ray detectors. Since it is a simple increase, when the intensity of the characteristic X-ray detected by one X-ray detector is larger than the intensity of the characteristic X-ray detected by another X-ray detector, the weighting factor for the one X-ray detector May be greater than or equal to the weighting factor of other X-ray detectors. For example, the weighting factor may be increased stepwise as the relative intensity ratio increases. When the intensity of the characteristic X-rays detected by the two X-ray detectors is the same, the weighting coefficient is the same for one X-ray detector as compared to another X-ray detector having a smaller relative intensity ratio. For the other X-ray detector, the weighting factor may be larger.

  In the first to fifth embodiments, the X-ray detectors 11, 12, 13, and 14 are semiconductor detectors using SDD. However, the X-ray detectors 11, 12, 13, and 14 are SDD. Other than the semiconductor detector, a detector other than the semiconductor detector may be used. Further, in the first to fifth embodiments, the energy dispersive type that separates and detects X-rays by energy is shown. However, the X-ray analyzer separates and detects X-rays by wavelength. It may be a form. In this form, the X-ray analyzer generates a spectrum in which the wavelength of the X-ray is associated with the count number, and generates an X-ray intensity distribution having a wavelength corresponding to a specific element.

DESCRIPTION OF SYMBOLS 1 X-ray detection part 11, 12, 13, 14 X-ray detector 2 Signal processing part 3 Control apparatus 31 CPU
32 RAM
34 Storage Unit 41 Electron Gun 42 Electron Lens System 43 Sample Stand 44 X-ray Source 45 Drive Unit 5 Sample 6 Recording Medium 61 Computer Program

Claims (7)

In an X-ray analyzer comprising: a scanning unit that scans a sample with a beam; and a plurality of X-ray detectors that detect X-rays generated from a portion irradiated with the beam on the sample by scanning by the scanning unit;
A plurality of X-ray intensities detected by the plurality of X-ray detectors for each of a plurality of portions irradiated with a beam on the sample by scanning by the scanning unit are compared with a relative ratio of each X-ray intensity. A calculation unit for calculating a weighted addition value obtained by multiplying each X-ray intensity by a weighting factor that simply increases,
An intensity distribution generation unit that generates a corrected intensity distribution of X-rays by associating the weighted addition value calculated by the calculation unit with respect to each part irradiated with the beam on the sample. A featured X-ray analyzer. The X-ray analysis apparatus according to claim 1, wherein the calculation unit is configured to use a value obtained by dividing each X-ray intensity by a sum of the plurality of X-ray intensities as the weighting coefficient. The calculation unit is configured such that a weighting factor for the maximum X-ray intensity among the plurality of X-ray intensities is set to 1, and a weighting factor for other X-ray intensities is set to 0. Item 2. The X-ray analyzer according to Item 1. The calculation unit calculates a value obtained by dividing an integral value of a specific energy range or wavelength range of X-rays detected by each X-ray detector by a value obtained by adding the integral values over the plurality of X-ray detectors. The X-ray analyzer according to claim 1, wherein the X-ray analyzer is configured to use the weighting factor. The calculation unit is configured to calculate the weighted addition value for a plurality of X-ray intensities detected by the plurality of X-ray detectors for X-rays caused by a specific element,
The X-ray analyzer according to any one of claims 1 to 4, wherein the intensity distribution generation unit is configured to generate an X-ray intensity distribution caused by the specific element. . In an X-ray analyzer comprising an irradiation unit for irradiating a beam to a sample, and a plurality of X-ray detectors for detecting X-rays generated from a portion irradiated with the beam on the sample,
Weighted addition in which a plurality of X-ray intensities detected by the plurality of X-ray detectors are added after multiplying each X-ray intensity by a weighting factor that simply increases with respect to the relative ratio of each X-ray intensity. A calculation unit for calculating a value;
An X-ray analysis apparatus comprising: a spectrum generation unit that generates a spectrum using the weighted addition value calculated by the calculation unit for each X-ray energy or wavelength as an X-ray intensity. In a computer program for causing a computer to analyze a result of detecting X-rays generated from a sample scanned with a beam by a plurality of X-ray detectors,
A plurality of X-ray intensities detected by the plurality of X-ray detectors for each of a plurality of portions irradiated with a beam on the sample by scanning are compared with a relative ratio of each X-ray intensity. A step of calculating a weighted addition value obtained by multiplying each X-ray intensity by a simple increasing weighting factor;
And causing the computer to generate an X-ray intensity distribution by associating each portion irradiated with the beam with a weighted addition value calculated for each portion.

Images