JP4439984B2 - X-ray analysis method and apparatus having optical axis adjustment function - Google Patents

Description

  The present invention relates to an X-ray analysis method and apparatus having an optical axis adjustment function for adjusting an optical axis using a half sample.

  Conventionally, in X-ray analysis such as X-ray fluorescence analysis, each part of a sample designated based on the display on the image of the sample surface imaged by the imaging means is two-dimensionally expressed by an rθ stage or the like. It is known to measure the distribution of content, film thickness, etc. of each part by measuring the X-ray intensity distribution (mapping measurement) through the aperture (diaphragm) while moving it with a detecting means. .

In this measurement, in order to adjust the optical axis, two materials with different constituent elements are joined, using a halved sample whose boundary line is a straight line, the expected position of the diaphragm and the rotation center of the θ stage Is known to match (for example, Patent Document 1). In this prior art, a half sample for adjusting the optical axis is placed on a θ stage in a predetermined direction, and X-ray intensity distribution is measured while moving in the r direction, and X-ray intensity distribution is moved while moving the diaphragm. By performing the measurement, the expected position of the diaphragm on the sample surface is matched with the rotation center of the θ stage.
JP 2001-281177 A

  However, in this prior art, since it is assumed that the half sample is placed on the θ stage in a predetermined direction, it is necessary to manually place the half sample in the predetermined direction. Further, the error between the direction in which the sample is placed and the predetermined direction propagates to the error of the adjustment position expected for the diaphragm.

  The present invention provides an X-ray analysis method and apparatus having an optical axis adjustment function that can adjust the optical axis correctly regardless of the direction in which the halved sample for optical axis adjustment is placed, by solving the above-described problems. It is aimed.

In order to achieve the above object, an X-ray analysis method and apparatus having an optical axis adjustment function according to the present invention provides a sample region designated based on a display on an image of a sample surface imaged by an imaging means, Sample movement consisting of a plane moving stage that moves the sample toward its surface and a θ stage that rotates the sample around its surface normal so that the X-ray analysis means for analyzing only a specific part of the sample is positioned at the expected position The X-ray intensity distribution is measured by the X-ray analysis means while being moved using the means, the measurement origin on the image, the expected position of the X-ray analysis means, and the θ stage. The optical axis is adjusted so as to coincide with the rotation center.
At this time, a halved sample having a linear reference line is used as an optical axis adjusting sample, and the X-ray analyzing means is moved to a plurality of arbitrary prospective positions on the sample surface. Then, at each of a plurality of arbitrary prospective positions of the X-ray analysis means, the halved sample is moved to a plurality of moving positions by the plane moving stage, and further, the halved sample is rotated on the θ stage at each moving position. By measuring the distribution of the X-ray intensity, the half angle, which is the rotation angle of the θ stage when the reference line of the half sample crosses an arbitrary prospective position, is detected.
Thereafter, based on the change in the half angle at the plurality of arbitrary prospective positions, the movement position of the plane moving stage in which the reference line of the half sample is parallel to the trajectories of the plurality of arbitrary prospective positions is detected, Set as the origin of the moving stage, and then set the expected position of the X-ray analyzing means so that the rotation center of the θ stage at the moving position and the expected position of the X-ray analyzing means coincide with each other. The measurement origin on the image is set so that the rotation center matches the measurement origin on the image.

  According to this configuration, the X-ray intensity distribution measurement is performed while rotating the half sample at the θ stage for each movement position of the plane moving stage at a plurality of arbitrary prospective positions of the X-ray analysis means. The movement position of the planar movement stage and the rotation angle of the θ stage are detected so that the reference line is parallel to the trajectories of a plurality of arbitrary expected positions. As a result, regardless of the orientation in which the halved sample is placed on the θ stage, the reference line of the halved sample passing through the rotation center of the θ stage is parallel to the trajectories of a plurality of arbitrary prospective positions. Since the state on the trajectory can be detected, the rotation center of the θ stage at the moving position of the planar moving stage is matched with the expected position of the X-ray analysis means, and the rotation center of the θ stage and the measurement origin on the image are set. By matching, the optical axis can be adjusted correctly.

  Preferably, the planar moving stage of the sample moving means is an r stage that moves the sample linearly. In this case, the optical axis adjustment can be accurately performed at low cost using the existing rθ stage. More preferably, the sample moving means also serves as a means for transporting the sample from the loading position to the measurement position.

  Preferably, the plane moving stage of the sample moving means is a φ stage for revolving the sample. In this case, the optical axis adjustment can be accurately performed at low cost using the existing φθ stage. More preferably, the sample moving means also serves as a means for transporting the sample from the loading position to the measurement position.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a fluorescent X-ray analyzer having an optical axis adjustment function according to the first embodiment of the present invention. FIG. 2A shows a halved sample used as an optical axis adjusting sample, and FIG. 2B shows the operating state of the apparatus. The apparatus shown in FIG. 1 is configured so that the portion of the sample designated based on the display on the image of the sample surface imaged by the imaging means 12 such as a CCD is at the expected position of the X-ray analysis means (diaphragm) 5. Then, while moving the sample two-dimensionally using the sample moving means (rθ stage), measurement is performed by the detecting means 4 through the diaphragm 5 and the distribution measurement (mapping measurement) of the fluorescent X-ray intensity is performed. Measure distribution of content, film thickness, etc. The X-ray analysis means (diaphragm) 5 analyzes only a specific part of the sample, and controls the measurement area by limiting the area for receiving the fluorescent X-ray B2 generated from the sample. The detection means 4 includes a spectroscopic element 7 that splits the fluorescent X-ray B2 that has passed through the diaphragm 5 through the slit 6, and a detector 8 that measures the intensity of the spectroscopic fluorescent X-ray B2.

  As the sample moving means for moving the sample surface two-dimensionally, as shown in FIG. 3A, the plane moving stage 16 for moving the sample S in the direction of the surface and the sample S are rotated around the normal of the surface. The θ stage 17 is used. For example, an r stage that linearly moves the sample S is used as the plane moving stage 16. The rθ stage including the r stage 16 and the θ stage 17 is provided with a θ stage 17 below the r stage 16, for example. The θ stage 17 holds the sample holder 43 in which the sample S is stored, and is provided so as to be freely rotatable horizontally (θ rotation) about the drive shaft 45 in order to rotate the sample S.

  The apparatus shown in FIG. 1 has an optical axis adjustment function, and includes optical axis adjustment means 20 that matches the measurement origin on the image, the expected position of the diaphragm 5, and the rotation center of the θ stage 17. This optical axis adjustment is generally performed only during device assembly adjustment.

  The optical axis adjusting means 20 uses a half sample S described later as an optical axis adjusting sample, and includes an X-ray analyzing means (diaphragm) moving means 15, a half angle detecting means 21, and a setting control means 22. ing. The half angle detection means 21 and the setting control means 22 are provided in the control means 24. The control means 24 further controls the diaphragm moving means 15 and displays the image on the display 28 by the imaging means 12. In addition to display control, the entire device is controlled.

  As shown in FIG. 2 (A), a halved sample S used as an optical axis adjusting sample is a disc in which two substances having different constituent elements, for example, Cu and Al, are joined and the boundary line is a straight line. It has a shape. As shown in the figure, when the boundary line passes through the rotation center 45 (FIG. 3A) of the θ stage 17 in a state where the half sample S is held on the θ stage 17, this boundary line is used as the half sample. The reference line L indicates the direction of S (arrow in FIG. 2A). When the boundary line does not pass through the rotation center 45 of the θ stage 17, a line parallel to the boundary line and passing through the rotation center 45 of the θ stage 17 becomes the reference line L. Here, the half sample S is a disc and the center thereof coincides with the rotation center 45 of the θ stage 17, but this need not be the case.

  A diaphragm moving means 15 comprising a driving means such as a pulse motor linearly moves the expected position on the sample surface of the diaphragm 5 to a plurality of, for example, two arbitrary expected positions. The direction of X-rays passing through the diaphragm 5 The diaphragm 5 is moved in a horizontal direction orthogonal to the plane view. As shown in FIG. 2B, a line on the sample surface connecting the positions 31 and 32 that are the trajectories of the arbitrary prospective positions 31 and 32 is defined as a diaphragm movement axis 36.

First, the half angle detection means 21 measures the X-ray intensity distribution by the detection means 4 at two arbitrary prospective positions 31 and 32 of the diaphragm 5. In this distribution measurement, for example, the half sample S is r-staged at each of two arbitrary prospective positions 31 and 32 (hereinafter simply referred to as diaphragm positions) that are shifted by −2 mm and +2 mm, respectively, from the temporary origin 30. 16, the movement position (hereinafter, simply referred to as “r stage position”) is sequentially linearly moved to a plurality of positions, for example, −1 mm, 0 mm, and +1 mm, and the halved sample S at each r stage position. Is performed while rotating 360 ° on the θ stage 17. Then, based on this distribution measurement, a half angle that is a rotation angle of the θ stage 17 when the reference line L of the half sample S rotates and traverses an arbitrary expected position is detected for each r stage position.
The r stage position 0 mm obtained by setting the half sample S on the r stage 16 and linearly moving it is set as a temporary measurement initial position. Further, the rotation angle of the θ stage 17 is, for example, an angle rotated clockwise by setting the initial state of the θ stage 17 at each turret angle to 0 °.

  The setting control means 22 detects two halved angle trend lines based on the change in the halved angle at the two arbitrary prospective positions 31 and 32 described above. The r stage where the reference line L of the halved sample S is parallel to the diaphragm movement axis 36, that is, the rotation center 45 of the θ stage 17 is on the diaphragm movement axis 36, at the point where the two half angle trend lines intersect. Since it is detected as a position, this is set as the origin of the r stage 16. In addition, the expected position of the diaphragm 5 is set so that the rotational center 45 of the θ stage 17 and the expected position of the diaphragm 5 at the r stage position coincide with each other, and further, the rotational center 45 of the θ stage 17 and the measurement origin on the image. Set the measurement origin on the image so that.

  The operation of the apparatus having the above configuration will be described based on the flowchart of FIG. First, the half sample S is set on the r stage 16 (step S1), and is loaded to a temporary initial measurement position by linear movement of the r stage 16 (step S2). In step S3, the diaphragm 5 is moved to an arbitrary expected position 31 deviated by −2 mm from the temporary origin 30 and then to an arbitrary expected position 32 deviated by +2 mm. In step S4, it is confirmed whether or not the diaphragm position is final. That is, it is confirmed whether or not the measurement at both arbitrary prospective positions 31 and 32 is completed.

  Next, in step S5, the r stage position is sequentially moved to −1 mm, 0 mm, and +1 mm in the r direction at the arbitrary prospective positions 31 and 32, respectively. In step S6, the X-ray intensity is measured while rotating the half sample S by 360 ° by θ rotation of the θ stage 17 at the r stage positions −1 mm, 0 mm, and +1 mm at the arbitrary prospective positions 31 and 32, respectively. Due to the linear movement of the halved sample S and the movement of θ rotation, the reference line L of the halved sample S is placed on the diaphragm moving shaft 36 for each of the r stage positions of −1 mm, 0 mm, and +1 mm at the arbitrary prospective positions 31 and 32. Will be detected. In step S7, it is confirmed whether or not the r stage position is final. That is, it is confirmed whether or not the measurement at each arbitrary prospective position 31, 32 is completed.

  FIG. 5 shows the measurement result of the X-ray intensity in step S6. FIG. 5A shows the measurement result at the arbitrary prospective position 31 at the diaphragm position −2 mm, and FIG. 5B shows the measurement result at the arbitrary prospective position 32 at the diaphragm position +2 mm. The inclined lines 51 and 52 in the figure indicate that the boundary line of the halved sample S has rotated and traversed at the arbitrary prospective positions 31 and 32.

  When the measurement at both arbitrary prospective positions 31 and 32 is completed in step S4, the reference line L of the halved sample S becomes parallel to the diaphragm movement axis 36 based on the measurement result of FIG. 5 (plan view). And the rotation angle of the θ stage 17 are detected (step S8). At the r stage position, the rotation center 45 of the θ stage 17 comes on the diaphragm moving shaft 36. Hereinafter, the operation of each means in step S8 will be described in detail.

  First, as shown in FIG. 6 (A), the halved angle detection means 21 measures 0 ° to 180 ° and 180 ° to 180 ° based on the measurement distribution of the r stage position + 1 mm in FIG. 5 (A), for example. The 360 ° measurement distribution is superimposed. Then, as shown in FIG. 6 (B), the intersection angle 53 has a half angle that is the rotation angle θ of the θ stage 17 when the reference line L of the half sample S rotates across the arbitrary prospective position 31. For example, 117.5 ° is detected. The intersection 53 is the midpoint of the inclined lines 51 and 52 when the boundary line of the halved sample S becomes the reference line L, and is shifted up and down from the midpoint otherwise. Instead of obtaining the intersection of the inclined lines 51 and 52, a further midpoint between both midpoints may be obtained. Similarly, the half angle at each diaphragm position and each r stage position is detected based on the measurement distributions of FIGS.

  Next, as shown in FIG. 7, the half angle is set to 37 °, 90 ° by the setting control means 22 in this order in the order of r stage position-1 mm, 0 mm, +1 mm at the diaphragm position-2 mm. , 117.5 °, showing a tendency to increase gradually, and at the diaphragm position +2 mm, the r-stage position is −1 mm, 0 mm, +1 mm in order, 117.5 °, 90 °, 37 ° , Two halved angle trend lines are detected.

  Then, as an intersection of both halved angle trend lines, the r stage position (0 mm in this case) and the θ stage 17 when the reference line L of the halved sample S is parallel to the diaphragm moving shaft 36 (overlapping in plan view). The rotation angle (here 90 °) is detected. At the r stage position, the rotation center 45 of the θ stage 17 comes on the diaphragm moving shaft 36, and this is set as the origin of the r stage 16.

  Next, the half sample S is moved to the detected r stage position (step S9). The state in which the θ stage 17 is at the r stage position is set as a new initial measurement position used in the measurement of the sample in the future, and the rotation center 45 of the θ stage 17 at that time is used as the measurement origin on the image and the expected position of the diaphragm 5. Is a position to match. The measurement origin on the image, for example, the center of the imaged screen is made to coincide with the rotation center 45 of the θ stage 17 is performed by a conventional technique. On the other hand, the expected position of the diaphragm 5 and the rotation center 45 of the θ stage 17 coincide with each other because the r direction of the r stage 16 can be set in step S9. Set about.

  First, the θ stage 17 is rotated by 90 ° from the rotation angle detected in step S8, and the boundary line of the halved sample S is made orthogonal to the diaphragm moving shaft 36 (step S10). In this state, X-ray intensity distribution measurement (diaphragm scan) is performed by moving the diaphragm 5 (step S11). Thereby, the midpoint of the inclined line indicating that the expected position of the diaphragm 5 has crossed the boundary line of the halved sample S is detected. Thereafter, the position of the diaphragm 5 is set to the position of the diaphragm 5 at the midpoint (step S12).

  If the boundary line is not the reference line L, in step 11, the halved sample S is rotated 180 ° and the diaphragm scan is performed again. Then, as described in step S8, the position of the diaphragm 5 when the position that the diaphragm 5 looks at crosses the reference line L as an intersection of two inclined lines or a further middle point of each inclined line. Is set at that position in step S12.

  As described above, in the first embodiment, the X-ray intensity distribution measurement is performed while the half sample S is rotated on the θ stage 17 for each movement position of the r stage 16 at the two arbitrary prospective positions 31 and 32 of the diaphragm 5. As a result, the moving position of the r stage 16 and the rotation angle of the θ stage 17 are detected so that the reference line L of the halved sample S is parallel to the diaphragm moving shaft 36. Thereby, the reference line L of the half sample S passing through the rotation center of the θ stage 17 is parallel to the diaphragm moving shaft 36 regardless of the direction in which the half sample S is placed on the θ stage 17 (the rotation center of the θ stage 17). 45 is on the diaphragm movement axis 36), the rotation center of the θ stage 17 at the movement position of the r stage 16 and the expected position of the diaphragm 5 are matched, and the rotation center of the θ stage 17 and the image By matching the above measurement origin, the optical axis can be adjusted correctly.

  Next, an X-ray analyzer having a fluorescence optical axis adjustment function according to the second embodiment will be described. In the second embodiment, a φθ stage is used as the sample moving means instead of the rθ stage. As shown in FIG. 3B, the φθ stage includes a φ stage 18 that moves the sample S in the direction of the sample surface and a θ stage 19 that rotates the sample S around the normal line of the surface. It also serves as a transport means to the measurement position. The φ stage 18 is provided, for example, so as to be freely rotatable (φ rotation) around the drive shaft 47, and transports the sample S by rotating (revolving) from the loading position to the measurement initial position. A lift 42 that moves up and down for loading and unloading the sample is provided at the loading position. The θ stage 19 holds a sample holder (not shown) in which the sample S is stored, and is provided so as to be horizontally rotatable (θ rotation) about the drive shaft 46 in order to rotate the sample S.

  In the second embodiment, the movement position of the r stage 16 of the first embodiment corresponds to the movement position of the φ stage 18. That is, as shown in FIG. 2C, in FIG. 2B, a plurality of movement positions −1 mm, 0 mm, and +1 mm by linear movement of the r stage 16 of the first embodiment are the second embodiment. Then, for example, −1 °, 0 °, and + 1 ° are a plurality of movement positions by the rotation of the φ stage 18. Other configurations are the same as those of the first embodiment.

  In the second embodiment, the halved sample S is moved to a plurality of movement positions by the φ stage 18 at each of the two arbitrary prospective positions 31 and 32 of the diaphragm 5, and the halved sample S is further moved at each movement position. By measuring the X-ray intensity distribution while rotating on the θ stage 19, the half angle which is the rotation angle of the θ stage 19 when the reference line L of the half sample S rotates and traverses the arbitrary prospective positions 31 and 32. Detect the angle. Then, based on the change in the half angle at the two arbitrary prospective positions 31, 32, the reference line L of the half sample S is parallel to the trajectory (diaphragm movement axis 36) of the two arbitrary prospective positions 31, 32. The moving position of the φ stage 18 is detected and set as the origin of the φ stage 18, and then the rotation center 46 of the θ stage 19 at the moving position and the expected position of the diaphragm 5 coincide with each other. The expected position is set, and further, the measurement origin on the image is set so that the rotation center 46 of the θ stage 19 and the measurement origin on the image coincide.

  As a result, the apparatus of the second embodiment measures the X-ray intensity distribution while rotating the halved sample S on the θ stage 19 at each rotation angle of the φ stage 18 at two arbitrary prospective positions 31 and 32 of the diaphragm 5. , The rotation angle of the φ stage 18 and the rotation angle of the θ stage 19 at which the reference line L of the halved sample S is parallel to the diaphragm movement axis 36 are detected, so that the halving is performed as in the first embodiment. Regardless of the direction in which the sample S is placed on the θ stage 19, the reference line L of the halved sample S passing through the rotation center 46 of the θ stage 19 is parallel to the diaphragm movement axis 36 (the rotation center 46 of the θ stage 19 moves through the diaphragm). The state of rotation on the axis 36) can be detected, so that the rotation center 46 of the θ stage 19 and the expected position of the diaphragm 5 at the moving position of the φ stage 18 are matched, Et al in, by matching the measurement origin on the center of rotation 46 and the image of θ stage 19, can be performed correctly the optical axis adjustment.

  In this embodiment, the X-ray analyzer having the optical axis adjustment function is a fluorescent X-ray analyzer, but the present invention is not limited to this, and other X-ray analyzers may be used.

  In this embodiment, the X-ray analysis means (diaphragm 5) is moved to two expected positions on the sample surface, but may be moved to three or more expected positions.

1 is a configuration diagram illustrating a fluorescent X-ray analyzer having an optical axis adjustment function according to a first embodiment of the present invention. FIG. (A) is a half sample, (B) (C) is a top view which shows the operation state of optical axis adjustment. (A) is a configuration diagram showing an rθ stage, and (B) is a configuration diagram showing a φθ stage. It is a flowchart which shows the optical axis adjustment operation | movement of FIG. (A), (B) is the distribution measurement figure measured in the arbitrary prospective position of each diaphragm. (A), (B) is a figure which shows the operation | movement which calculates | requires a half angle using a distribution measurement figure. It is a characteristic view which shows a half angle tendency line.

Explanation of symbols

5: Diaphragm (X-ray analysis means)
12: Imaging means 15: Diaphragm moving means 16: r stage (plane moving stage)
17: θ stage 18: φ stage
19: θ stage 20: optical axis adjusting means 21: half angle detecting means 22: setting control means L: reference line of half sample S: half sample

Claims (5)

The surface of the sample is oriented so that the designated portion of the sample based on the display on the image of the surface of the sample imaged by the imaging means comes to the expected position of the X-ray analysis means for analyzing only a specific portion of the sample. X-rays are analyzed by a detecting means for detecting fluorescent X-rays generated from the sample while being moved using a sample moving means comprising a plane moving stage to be moved to and a θ stage for rotating the sample around the normal line of the surface. An X-ray analysis apparatus for measuring an intensity distribution, comprising: an optical axis adjustment means for matching a measurement origin on an image, a predicted position of the X-ray analysis means, and a rotation center of the θ stage; axis alignment means, which use that half the samples have a straight boundary line as the optical axis adjustment sample, moves linearly to the X-ray analysis means into a plurality of arbitrary estimated position on the sample surface X-ray analysis The halved sample is moved to a plurality of moving positions by a plane moving stage at each of a plurality of arbitrary prospective positions of the means moving means and the X-ray analyzing means, and further, at each moving position, the halved sample is moved by the θ stage By measuring the distribution of the X-ray intensity while rotating, the rotation angle of the θ stage when a reference line passing through the rotation center of the θ stage that is parallel to or coincides with the boundary line rotates and traverses an arbitrary prospective position. A half angle detection means for detecting a half angle, and a plane moving stage in which the reference line overlaps a plurality of arbitrary prospective positions in plan view based on a change in half angle at the plurality of arbitrary prospective positions. Detect the moving position, set this as the origin of the plane moving stage, and then the rotation center of the θ stage at the origin of the plane moving stage The expected position of the X-ray analysis means is set so that the expected position of the X-ray analysis means matches, and the measurement on the image is performed so that the rotation center of the θ stage matches the measurement origin on the image. An X-ray analyzer having an optical axis adjustment function, comprising setting control means for setting an origin. In claim 1,
An X-ray analyzer having an optical axis adjustment function, wherein the plane moving stage of the sample moving means is an r stage that linearly moves the sample. In claim 1,
An X-ray analyzer having an optical axis adjustment function, wherein the plane moving stage of the sample moving means is a φ stage for revolving a sample.   2. The X-ray analysis apparatus according to claim 1, wherein the sample moving means also serves as a means for transporting the sample from a loading position to a measurement position. The surface of the sample is oriented so that the designated portion of the sample based on the display on the image of the surface of the sample imaged by the imaging means comes to the expected position of the X-ray analysis means for analyzing only a specific portion of the sample. X-rays are analyzed by a detecting means for detecting fluorescent X-rays generated from the sample while being moved using a sample moving means comprising a plane moving stage to be moved to and a θ stage for rotating the sample around the normal line of the surface. An X-ray analysis method for measuring an intensity distribution, comprising: an optical axis adjustment method for matching a measurement origin on an image, an expected position of the X-ray analysis means, and a rotation center of the θ stage; axis adjustment method, which uses a that half the samples have a straight boundary line as the optical axis adjustment sample, moves linearly to the X-ray analysis means into a plurality of arbitrary estimated position on the sample surface Let the X-ray At each of a plurality of arbitrary prospective positions of the analysis means, the halved sample is moved to a plurality of moving positions by a plane moving stage, and further, at each moving position, the X-ray intensity of the X-ray intensity is rotated while the halved sample is rotated on the θ stage. By performing distribution measurement, a half angle that is a rotation angle of the θ stage when a reference line passing through the rotation center of the θ stage, which is parallel or coincides with the boundary line, rotates and traverses an arbitrary prospective position, Based on the change in the half angle at the plurality of arbitrary prospective positions, the reference line detects the movement position of the planar movement stage overlapping the trajectory of the arbitrary prospective positions in plan view, and this is detected as the origin of the plane movement stage. Then, the rotation center of the θ stage at the origin of the plane moving stage matches the expected position of the X-ray analysis means. The optical axis adjustment function is used to set the expected position of the X-ray analysis means and to set the measurement origin on the image so that the rotation center of the θ stage matches the measurement origin on the image. X-ray analysis method.

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