JP2014196925A - Fluorescent x-ray analyzer, and depth direction analysis method used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent X-ray analyzer capable of obtaining information on an element contained at a position at certain depth in a sample in a nondestructive manner and with smaller restriction of measurement atmosphere conditions.SOLUTION: A fluorescent X-ray analyzer 1 comprises: an X-ray tube 10 which emits X-ray to a predetermined irradiation range of a sample S; and a detector 30 which detects fluorescent X-ray from a predetermined detection range of the sample S, and is equipped with: a first collimator (or first slit) 41 which is arranged between the X-ray tube 10 and the sample S and has a first opening for emitting X-ray into a set effective range of irradiation within a predetermined irradiation range; a second collimator (or second slit) 42 which is arranged between the sample and the detector 30 and has a second opening for detecting fluorescent X-ray from a set effective range of detection within a predetermined detection range; a first drive mechanism 43 which moves the first collimator 41; and a second drive mechanism 44 which moves the second collimator 42.

Description

  The present invention relates to a fluorescent X-ray analyzer that acquires information on elements contained in a sample and a depth direction analysis method used therefor.

  An X-ray fluorescence analyzer irradiates a solid sample, a powder sample, or a liquid sample with primary X-rays, and detects the X-rays emitted by being excited by the primary X-rays. Qualitative and quantitative analysis is performed.

  Some X-ray fluorescence analyzers include a collimator for narrowing a primary X-ray beam between an X-ray source that emits primary X-rays and a sample. The collimator is composed of, for example, a flat plate having a plurality of apertures with different diameters. By selecting an aperture with an appropriate diameter and positioning it on the optical axis of the X-ray, the irradiation range of the primary X-ray is set to the sample size. Is limited to a predetermined size according to According to such a fluorescent X-ray analyzer, when analyzing a micro sample or analyzing a micro area on the sample, the generation of fluorescent X-rays from other than the target measurement area is suppressed and a high S / N ratio is obtained. Has achieved.

  Further, a collimator provided on the optical axis of the X-ray between the X-ray source and the sample and capable of continuously changing the aperture size, and an input means for the measurer to specify the aperture size of the collimator are provided. A fluorescent X-ray analyzer is disclosed (for example, see Patent Document 1). According to such a fluorescent X-ray analyzer, it is possible to set the irradiation range of the primary X-ray to an optimum size according to the target measurement region.

  Furthermore, a measurement method that performs bulk analysis or foreign matter analysis at a predetermined depth in a thin film or solid sample, or specifies a place where a harmful element is mixed in a composite material is widely known. For example, total reflection X-ray fluorescence analysis (TXRF) for analyzing the incident angle of primary X-rays while scanning and oblique incidence X-ray fluorescence analysis (GIXRF) are used.

  On the other hand, as a measurement method for performing bulk analysis or foreign matter analysis at a predetermined depth in a thin film or solid sample by detecting other than fluorescent X-rays, beam-like ions (“primary ions”) are applied to the sample. Secondary ion mass spectrometry (SIMS), which detects ions (called “secondary ions”) generated by collisions between the primary ions and the sample at the molecular / atomic level (called “secondary ions”), There is X-ray photoelectron spectroscopy (ESCA) for analyzing the constituent elements of the sample and their electronic states by irradiating the sample with X-rays and measuring the energy of the generated photoelectrons.

JP 2009-002795 A

However, in the fluorescent X-ray analyzer as described above, the primary X-ray irradiation range can be set to an optimum size according to the target measurement region, but information on elements contained in the surface and inside of the sample is available. Could not be acquired individually. That is, it was impossible to specify which element is present at which depth in the sample.
In total reflection X-ray fluorescence analysis (TXRF) and oblique-incidence X-ray fluorescence analysis (GIXRF), the analysis is performed while scanning the incident angle of the primary X-ray, so that the sample stage or detector side has high accuracy. A drive mechanism system is required, and the apparatus is complicated.

In addition, secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (ESCA) require destruction of the sample surface by high-energy ion irradiation and measurement under ultra-high vacuum conditions, limiting the type of sample. Or there was a case that the sample was damaged.
Therefore, the present invention is a non-destructive and X-ray fluorescence analyzer that can acquire information on elements contained in a position at a predetermined depth in a sample while reducing restrictions on measurement atmosphere conditions, and is used for the apparatus. An object is to provide a depth direction analysis method.

  An X-ray fluorescence analyzer of the present invention made to solve the above problems includes an X-ray tube that emits X-rays to a predetermined irradiation range of a sample, and a detection that detects fluorescent X-rays from the predetermined detection range of the sample A fluorescent X-ray analyzer comprising a detector having a surface, disposed between the X-ray tube and the sample, for emitting X-rays to a set irradiation effective range within the predetermined irradiation range A first collimator or a first slit having a first opening and a second collimator disposed between the sample and the detector for detecting fluorescent X-rays from a set detection effective range within the predetermined detection range. A second collimator or a second slit having an opening, a first drive mechanism for moving the first collimator or the first slit, and a second drive mechanism for moving the second collimator or the second slit are provided.

Here, the “set irradiation effective range” is determined by the size of the first opening, and can be arbitrarily determined by the size of the first opening by a measurer or the like. Becomes a range smaller than the predetermined irradiation range of the X-rays emitted.
The “setting detection effective range” is determined by the size of the second opening, and can be arbitrarily determined by the size of the second opening by the measurer, etc., but the detector detects it. The range is smaller than a possible predetermined detection range.

  According to the fluorescent X-ray analyzer of the present invention, for example, the setting is made by moving the first collimator in a state where the predetermined irradiation range of the X-rays emitted from the X-ray tube is fixed (a state in which the optical system is maintained). Set the position of the effective irradiation range to the optimum position. Further, the position of the set detection effective range is set to an optimum position by moving the second collimator in a state where the predetermined detection range that can be detected by the detector is fixed (a state in which the optical system is maintained). As a result, the detector detects fluorescent X-rays from the measurement region (effective excitation region), which is a region where the set irradiation effective range and the set detection effective range overlap. At this time, by changing the position of the measurement region, which is the region where the set irradiation effective range and the set detection effective range overlap, any depth in the sample can be set as the measurement region, X-ray fluorescence from the depth can be detected.

  As described above, according to the X-ray fluorescence analyzer of the present invention, the non-destructive and measurement atmosphere conditions are reduced, and further, the X-ray tube and the detector are fixed and the predetermined in the sample is fixed. It is possible to obtain information on elements contained in the position of the depth.

(Means and effects for solving other problems)
In the above invention, the first drive mechanism moves the first collimator or the first slit so as to change the position of the set effective irradiation range in the predetermined irradiation range in a state where the X-ray tube is fixed. The second drive mechanism moves the second collimator or the second slit so as to change the position of the set detection effective range in the predetermined detection range with the detector fixed, thereby measuring the measurement region in the sample. You may make it change the depth of.

  In the above invention, the first drive mechanism moves the first collimator or the first slit in a plane orthogonal to the optical axis of the X-ray, and the second drive mechanism includes the second collimator or the first slit. The two slits may be moved in a plane parallel to the detection surface.

  In the above invention, the first switching mechanism moves the first collimator or the first slit stepwise so that the position of the set irradiation effective range in the predetermined irradiation range is changed stepwise. And the second drive mechanism has a second switching mechanism that moves the second collimator or the second slit stepwise so as to change the position of the setting detection effective range in the predetermined detection range stepwise. It may be.

  In the above invention, the X-ray tube is a point focus X-ray tube, and the first drive mechanism moves the first collimator, or the X-ray tube is a line focus X-ray. The first driving mechanism may move the first slit.

Furthermore, in the above invention, a solar slit may be provided between the X-ray tube and the first collimator or the first slit.
According to the fluorescent X-ray analyzer of the present invention, the spread of the X-ray beam can be suppressed and the analysis accuracy in the depth direction can be increased.

  And the depth direction analysis method of the present invention includes an X-ray tube that emits X-rays to a predetermined irradiation range of a sample, a detector having a detection surface that detects fluorescent X-rays from the predetermined detection range of the sample, A first collimator or a first slit disposed between the X-ray tube and the sample and having a first opening for emitting X-rays within a set irradiation effective range within the predetermined irradiation range; A second collimator or a second slit disposed between the detector and having a second opening for detecting fluorescent X-rays from a set detection effective range within the predetermined detection range; and a first collimator or first A depth direction analysis method used in a fluorescent X-ray analyzer including a first drive mechanism for moving one slit and a second drive mechanism for moving a second collimator or a second slit, wherein the X-ray tube is In a fixed state A setting irradiation effective range determining step for moving the first collimator or the first slit so as to change the position of the setting irradiation effective range in the irradiation range, and the setting detection effective range in the predetermined detection range with the detector fixed. A setting detection effective range determining step of moving the second collimator or the second slit so as to change the position.

1 is a schematic configuration diagram showing an example of an energy dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention. The figure explaining the positional relationship with a measurement area | region in a X-ray tube, a 1st collimator, a detector, a 2nd collimator, and a sample.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it is needless to say that various aspects are included without departing from the gist of the present invention.

  FIG. 1 is a schematic configuration diagram illustrating an example of an energy dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention. The energy dispersive X-ray fluorescence analyzer 1 includes an analysis chamber 20 in which a sample S is disposed, an X-ray tube 10, a first collimator 41, a detector 30, a second collimator 42, and a CCD camera 51. The device housing 50 arranged, a first drive mechanism 43 that moves the first collimator 41, a second drive mechanism 44 that moves the second collimator 42, the X-ray tube 10, the detector 30, and the first drive mechanism. 43, a second drive mechanism 44, and a computer 60 for controlling the CCD camera 51.

  The analysis chamber 20 includes a plate-like sample base 21 and a cylindrical upper chamber 22 having a plate-like upper surface. A circular opening 21 a having a diameter of 15 mm, for example, is formed at the center of the sample base 21. The inside of the upper chamber 22 is connected to a vacuum pump (not shown) and is evacuated to a vacuum by the vacuum pump.

  A sample base 21 is attached to the upper surface of the apparatus housing 50. An X-ray tube 10, a first collimator 41, a detector 30, a second collimator 42, and a CCD camera 51 are disposed inside the apparatus housing 50. Here, FIG. 2 is a diagram for explaining the positional relationship among the X-ray tube 10, the first collimator 41, the detector 30, the second collimator 42, and the measurement region in the sample S.

  The CCD camera 51 is provided at a position facing the analysis surface of the sample S, and outputs an analysis surface image of the sample S to the computer 60.

  The X-ray tube 10 is a point-focused X-ray tube having, for example, a housing, and a target (not shown) as an anode and a filament (not shown) as a cathode are arranged inside the housing. Has been. Thus, by applying a high voltage between the target and the filament, the thermoelectrons emitted from the filament collide with the target, and primary X-rays generated at the target are emitted. The X-ray tube 10 is fixed so as to be positioned on the left (right) lower side of the opening 21a of the sample base 21, and primary X-rays emitted from the X-ray tube 10 are irradiated in a predetermined irradiation range (for example, in the opening 21a). It is configured to be incident on a circular shape having a diameter of 10 mm. Therefore, as shown in FIG. 2, the predetermined measurement region (A to I) in the sample S is irradiated with the primary X-rays by bringing the analysis surface of the sample S into contact with the opening 21 a. ing.

  The first collimator 41 is a flat plate having a circular opening (for example, 1 mm in diameter) 41a, and is disposed between the X-ray tube 10 and the opening 21a. As a result, the primary X-ray in the set effective irradiation range (for example, circular shape with a diameter of 1 mm) within the primary X-ray emitted from the X-ray tube 10 within the predetermined irradiation range (for example, circular shape with a diameter of 10 mm) It passes through the opening 41a of 41. As a result, for example, as shown in FIG. 2A, the set measurement regions (DF) in the sample S are irradiated with primary X-rays.

  The first collimator 41 can be moved in a plane orthogonal to the optical axis of the primary X-ray by the first drive mechanism 43. Therefore, primary X-rays in an arbitrary set irradiation effective range (for example, a circular shape with a diameter of 1 mm) within a primary X-ray emitted from the X-ray tube 10 (for example, a circular shape with a diameter of 10 mm) are first It passes through the opening 41a of the collimator 41. Thereby, as shown in FIG. 2 (a), the set measurement effective region (DF) in the sample S is irradiated by the primary X-ray, or the set measurement effective in the sample S as shown in FIG. 2 (b). The region (A to C) is irradiated with primary X-rays.

  The detector 30 has, for example, a housing in which an introduction window (detection surface) is formed, and a detection element (semiconductor element) that detects fluorescent X-rays is disposed inside the housing. The detector 30 is fixed so as to be positioned below the right (left) of the opening 21a of the sample base 21, and the fluorescence X generated in a predetermined detection range (for example, a circular shape having a diameter of 10 mm) on the analysis surface of the sample S. The line is configured to enter the introduction window. Therefore, as shown in FIG. 2, when a predetermined irradiation range (for example, a circular shape having a diameter of 10 mm) on the analysis surface of the sample S is irradiated with primary X-rays, the detector 30 has a predetermined measurement region (A to I) in the sample S. ) Is detected.

  The second collimator 42 is a flat plate having a circular opening (for example, 1 mm in diameter) 42a, and is disposed between the detector 30 and the opening 21a. Thereby, fluorescent X-rays generated in a set detection effective range (for example, a circular shape with a diameter of 1 mm) within a predetermined detection range (for example, a circular shape with a diameter of 10 mm) on the analysis surface of the sample S are converted into the opening 42a of the second collimator 42. Is supposed to pass through. As a result, for example, as shown in FIG. 2A, fluorescent X-rays generated in the set measurement effective region (B, E, H) in the sample S are incident on the detector 30.

  The second collimator 42 can be moved in a plane parallel to the detection surface by the second drive mechanism 44. Therefore, the fluorescent X-rays generated in an arbitrary set detection effective region (for example, a circular shape with a diameter of 1 mm) among the fluorescent X-rays generated in a predetermined detection region (for example, a circular shape with a diameter of 10 mm) in the sample S are second It passes through the opening 42a of the collimator 42. As a result, as shown in FIG. 2A, the fluorescent X-rays generated in the set measurement effective region (B, E, H) in the sample S are detected by the detector 30, or as shown in FIG. In addition, the fluorescent X-rays generated in the set measurement effective region (C, F, I) in the sample S are detected by the detector 30.

  The computer 60 includes a CPU (control unit) 61, an input device 62, and a display device 63. The function processed by the CPU 61 will be described as a block. An image acquisition unit 61a that acquires an analysis plane image of the sample S from the CCD camera 51 and displays it on the display device 63, and the intensity of fluorescent X-rays (fluorescence spectrum) from the detector 30. ), A X-ray source control unit 61c that emits primary X-rays from the X-ray tube 10, a drive mechanism control unit 61d that controls the first drive mechanism 43 and the second drive mechanism 44, Have

  The drive mechanism control unit 61 d performs control to output a control signal to the first drive mechanism 43 and the second drive mechanism 44 based on an input signal from the input device 62. For example, the measurer determines the position of the effective irradiation range while observing a numerical value indicating the position (incident angle) of the first collimator 41 displayed on the display device 63, the density of the material of the sample S, and the like. The first collimator 41 is moved using the input device 62 (set irradiation effective range determination step), and the numerical value indicating the position (detection angle) of the second collimator 42 displayed on the display device 63 and the density of the material of the sample S In order to determine the position of the setting detection effective region, the second collimator 42 is moved using the input device 62 (setting detection effective range determination step).

  Here, the energy dispersive X-ray fluorescence spectrometer 1 is used to analyze whether or not a metal foreign matter is contained in the sample S. When the sample S contains a metal foreign matter, which position of the sample S is Depth direction analysis method for analyzing whether or not a metal foreign matter is contained in the frame will be described. Here, a case where a metal foreign object exists in the region C in the resin sample S will be described. Further, in the energy dispersive X-ray fluorescence spectrometer 1 according to the embodiment of the present invention, while the same resin sample S is analyzed, the X-ray tube 10 and the detector 30 are fixed (the optical system is maintained). State).

  First, the measurer observes the numerical value indicating the position of the first collimator 41 displayed on the display device 63, the numerical value indicating the position of the second collimator 42, the density of the material of the sample S, etc., for example, FIG. ), The first collimator 41 and the second collimator 42 are moved using the input device 62. Thereby, the fluorescence spectrum from the set measurement effective region E in the resin sample S is acquired. At this time, since the primary X-rays do not reach the metal foreign object, fluorescent X-rays other than the scattered radiation from the resin sample S and the X-ray tube 10 are not detected.

  Next, the measurer observes the numerical value indicating the position of the first collimator 41 displayed on the display device 63, the numerical value indicating the position of the second collimator 42, the density of the material of the sample S, etc., for example, FIG. The first collimator 41 and the second collimator 42 are moved using the input device 62 so as to be in the state of b). Thereby, the fluorescence spectrum from the set measurement effective region C in the resin sample S is acquired. At this time, since the primary X-rays reach the metal foreign object, the fluorescent X-ray derived from the metal foreign object component is detected. However, even if no metal foreign matter exists in the set measurement effective region C, the result of exciting the metal foreign matter existing in the region F or the region I by the high energy X-rays scattered in the set measurement effective region C is reflected. Therefore, it cannot always be said that there is a metal foreign object in the set measurement effective region C.

  Therefore, the first collimator 41 and the second collimator 42 are moved so as to acquire the fluorescence spectrum from the set measurement effective region F, or the first collimator is acquired so as to acquire the fluorescence spectrum from the set measurement effective region I. 41 and the second collimator 42 are moved to acquire a plurality of fluorescence spectra. Then, by calculating the average depth by obtaining the relationship between the incident angle and the detection angle, the spread of the X-ray beam, the density of the material of the sample S, the mass absorption coefficient, etc., the set measurement effective region F and the set measurement It is confirmed whether a metal foreign object exists in the effective area I.

  Note that, in order to specify the location of the metal foreign object, measurement results based on a plurality of positional relationships between the first collimator 41 and the second collimator 42 may be required, but a certain depth such as uniform material analysis or film analysis may occur. When the present invention is applied to the sample S having no variation in composition, the number of measurements may be reduced. It is also possible to analyze the film thickness of the sample S, such as a single layer film or a multilayer film, or the depth direction of composition information.

  As described above, according to the energy dispersive X-ray fluorescence spectrometer 1 of the present invention, a highly accurate driving mechanism system on the sample stage or the detector 30 side while reducing restrictions on the non-destructive and measurement atmosphere conditions. The fluorescence spectrum contained in the position of the predetermined depth in the sample S can be acquired with a simple system without using the.

<Other embodiments>
(1) In the energy dispersive X-ray fluorescence spectrometer 1 described above, the configuration using the X-ray tube 10 and the first collimator 41 that are point-focus X-ray tubes has been shown. The X-ray tube and the first slit may be used. Moreover, it is good also as a structure which uses a 2nd slit. Further, a solar slit may be provided between the X-ray tube and the first collimator or the first slit.

(2) In the energy dispersive X-ray fluorescence spectrometer 1 described above, the measurer displays a numerical value indicating the position (incident angle) of the first collimator 41 displayed on the display device 63 and the position (detection angle) of the second collimator 42. While the first collimator 41 and the second collimator 42 are moved by using the input device 62 while observing the numerical value indicating the density of the sample S, the density of the material of the sample S, and the like, 42 may be automatically moved step by step (for example, three steps) by a switching mechanism.

(3) In the above-described embodiment, the energy dispersive and bottom irradiation type X-ray fluorescence analyzer has been described as an example. However, the top surface irradiation type that irradiates the primary X-ray from the top surface of the sample S, or wavelength dispersion. The present invention can be similarly applied to a type of fluorescent X-ray analyzer.

  The present invention can be used in a fluorescent X-ray analyzer or the like that acquires information on elements contained in a sample.

DESCRIPTION OF SYMBOLS 1 X-ray fluorescence analyzer 10 X-ray tube 20 Analysis chamber 30 Detector 41 First collimator 41a Opening of the first collimator (first opening)
42 Second collimator 42a Second collimator opening (second opening)
43 First drive mechanism 44 Second drive mechanism S Sample

Claims (7)

An X-ray tube for emitting X-rays to a predetermined irradiation range of the sample;
A fluorescent X-ray analyzer comprising a detector having a detection surface for detecting fluorescent X-rays from a predetermined detection range of the sample,
A first collimator or a first slit disposed between the X-ray tube and the sample, and having a first opening for emitting X-rays to a set irradiation effective range within the predetermined irradiation range;
A second collimator or a second slit disposed between the sample and the detector and having a second opening for detecting fluorescent X-rays from a set detection effective range within the predetermined detection range;
A first drive mechanism for moving the first collimator or the first slit;
A fluorescent X-ray analyzer comprising: a second drive mechanism for moving the second collimator or the second slit.   The first drive mechanism moves the first collimator or the first slit so as to change the position of the set irradiation effective range in the predetermined irradiation range in a state where the X-ray tube is fixed. The depth of the measurement region in the sample is changed by moving the second collimator or the second slit so as to change the position of the set effective detection range in the predetermined detection range with the detector fixed. The fluorescent X-ray analyzer according to claim 1, wherein: The first drive mechanism moves the first collimator or the first slit in a plane perpendicular to the optical axis of the X-ray,
3. The X-ray fluorescence analyzer according to claim 1, wherein the second drive mechanism moves a second collimator or a second slit in a plane parallel to the detection surface. The first drive mechanism has a first switching mechanism that moves the first collimator or the first slit stepwise so that the position of the set irradiation effective range in the predetermined irradiation range is changed stepwise,
The second drive mechanism has a second switching mechanism that moves the second collimator or the second slit stepwise so as to change the position of the setting detection effective range in the predetermined detection range stepwise. The fluorescent X-ray analyzer according to any one of claims 1 to 3.   The X-ray tube is a point-focus X-ray tube, and the first drive mechanism moves a first collimator, or the X-ray tube is a line-focus X-ray tube, The fluorescent X-ray analyzer according to claim 1, wherein the first drive mechanism moves the first slit.   The fluorescent X-ray analyzer according to any one of claims 1 to 5, wherein a solar slit is provided between the X-ray tube and the first collimator or the first slit. An X-ray tube for emitting X-rays to a predetermined irradiation range of the sample;
A detector having a detection surface for detecting fluorescent X-rays from a predetermined detection range of the sample;
A first collimator or a first slit disposed between the X-ray tube and the sample, and having a first opening for emitting X-rays to a set irradiation effective range within the predetermined irradiation range;
A second collimator or a second slit disposed between the sample and the detector and having a second opening for detecting fluorescent X-rays from a set detection effective range within the predetermined detection range;
A first drive mechanism for moving the first collimator or the first slit;
A depth direction analysis method used in a fluorescent X-ray analyzer comprising a second drive mechanism for moving a second collimator or a second slit,
A setting irradiation effective range determination step of moving the first collimator or the first slit so as to change the position of the setting irradiation effective range in the predetermined irradiation range in a state where the X-ray tube is fixed;
A setting detection effective range determining step of moving the second collimator or the second slit so as to change the position of the setting detection effective range in the predetermined detection range with the detector fixed. Direction analysis method.

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