JPH04208900A - Setting of irradiation angle of energy beam - Google Patents

Abstract

PURPOSE:To enable setting of angle easily and accurately in micron level by attaining a process to irradiate in advance energy beam to a energy intensity detector and to detect the energy intensity, and a process to shield the energy beam. CONSTITUTION:A monocolor X-ray is irradiated directly to a scintillation counter (energy intensity detector) 3. Here is detected the initial energy intensity prior to the shielding of X-ray. Next, a specimen 4 is fixed on a stage 5 and maintained in the state slanted in advance to the direction of the monocolor X-ray. Then, by elevating this stage 5, the monocolor X-ray is shielded at an optically smooth surface on the specimen 4. Finally, the stage 5 is rotated around the center axis parallel to the optically smooth surface on the specimen 4 and perpendicular to the radiation direction of the monocolor X-ray by 0.06 degree counterclockwise to finish the setting of irradiation angle. By this, monocolor X-ray can be irradiated accurately and with desired angle to the optically smooth surface on the specimen 4.

Description

[Detailed description of the invention]

[00011

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting an energy beam irradiation angle for irradiating an energy beam at a predetermined angle onto a sample placed on a rotatable and movable stage. [0002] [0002] Energy ray irradiation angle setting technology is a total reflection method in which energy rays such as X-rays are totally reflected on an optically smooth surface of a sample, and the fluorescence emitted from the sample at that time is detected. This is particularly important in reflection X-ray fluorescence spectroscopy. [0003] Conventionally, the sample and irradiation direction have been adjusted so that the energy beam is irradiated at a predetermined angle by a so-called mechanical positioning method, a method using a laser beam, or a method of continuously changing the glancing angle. Ta. [0004] In the mechanical positioning method, a plurality of Si blocks having surfaces inclined at a predetermined angle with respect to the energy beam irradiation direction are arranged, and the optically smooth surface of the sample is placed on these surfaces. The angle was set by pressing against it. [0005] Furthermore, in a method using a laser beam, the laser beam is directly irradiated onto the sample, and the distance to the sample is measured based on the reflected light. [0006] Furthermore, in the method of continuously changing the glancing angle, the intensity of α is detected in St- when the glancing angle, which is the angle when looking at the sample from the excitation source, is continuously changed, The purpose was to find the critical angle at that time. [0007]

[Problems to be Solved by the Invention] Mechanical positioning methods are preferable because they have a simple mechanism and are easy to use, but they do not allow dust to adhere to the surface of the Si block material or dimensional errors due to temperature changes. Therefore, it could not be used as an angle setting method that required accuracy on the order of microns. [0008] Furthermore, according to the method using a laser beam, a detector must be installed to measure the reflected light of the laser beam, so the laser device cannot be placed directly above the sample. Therefore, it is necessary to adjust the position at a location different from the actual measurement location, and then move the sample to the original measurement location. In this case, movement accuracy in both height and measurement position is required, but it is quite difficult to achieve these movement accuracy on the order of microns. [0009] Furthermore, according to the method of continuously changing the glancing angle, statistical fluctuations in measured values, smoothness of the sample surface, etc.
It was quite difficult to accurately determine the critical angle due to other influencing factors. [00101] Therefore, an object of the present invention is to provide a method for setting an illumination angle that can easily and accurately set an angle on the order of microns. [00111

[Means for Solving the Problems] In order to solve the above objects, the present invention irradiates an energy beam at a predetermined angle onto a sample that is placed on a rotatable and movable stage and has an optically smooth surface. In the method of setting the irradiation angle of the energy beam,
A step of detecting the energy intensity by irradiating the energy beam onto an energy intensity detector in advance; a step of blocking the energy beam with an optically smooth surface of the sample by moving the stage; By rotating and/or moving the stage while comparing the energy intensity before and after blocking by the optically smooth surface,
a step of aligning the irradiation direction of the energy beam with the optically smooth surface of the sample; and a step of aligning the irradiation direction of the energy beam with the optically smooth surface of the sample; and rotating the stage by the predetermined angle. [0012] Since the present invention is constructed as described above, the energy intensity when it is blocked by the optically smooth surface of the sample is lower than the energy intensity when it is not blocked. Therefore, the stage is rotated and/or moved so that the energy intensity increases. In this manner, the stage is rotated and/or moved repeatedly until the energy intensity reaches the maximum, that is, the energy intensity before interruption. When the energy intensity is at its maximum, the optically smooth surface of the sample is parallel to the energy beam, so by rotating the sample by a predetermined angle around the rotation axis perpendicular to the irradiation direction of the energy beam, the energy beam can be The irradiation direction is set at a predetermined angle. [0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description will be omitted. [0014] FIGS. 1 to 4 are process diagrams showing a method of setting an energy beam irradiation angle according to an embodiment. First, a rotating anticathode target 1 is used as an X-ray source to emit X-rays, and the spectroscopic crystal 2 is irradiated with the X-rays to make them monochromatic. This monochromatic X-ray is directly incident on a scintillation counter (energy intensity detector) 3. Here, the initial energy intensity before the X-rays are blocked is detected (FIG. 1). [0015] Next, the sample 4, which has an optically smooth surface, is fixed on a stage 5 that can be rotated or moved up and down about an axis perpendicular to the plane of the paper, and the irradiation direction of monochromatic X-rays is adjusted. Hold it in a tilted position. Thereafter, the stage 5 is raised and the monochromatic X-rays are blocked by the optically smooth surface of the sample 4 (FIG. 2). In this state, the monochromatic X-rays do not need to be totally reflected on the sample 4, so the setting can be made relatively easily. [0016] Next, by rotating and moving the stage 5 while monitoring the scintillation counter 3,
The inclination angle of the optically smooth surface of the sample 4 with respect to the monochromatic X-rays is adjusted to 0 degrees, that is, the monochromatic X-rays are adjusted to be parallel to the optically smooth surface of the sample 4 (FIG. 3). This state can be easily confirmed because it is indicated by the fact that the energy intensity of the scintillation counter 3 matches the energy intensity before the sample 4 intercepts it. Specifically, first stage 5
Swing the scintillation counter 3 at a predetermined angle.
The change in energy intensity is monitored. For example, if stage 5 is tilted to the left (Figure 2) to block monochromatic X-rays and then rotated clockwise, the energy intensity will initially increase gradually, reach a maximum value, and then decrease again. do. If this maximum value is equal to the energy intensity before being blocked by the optically smooth surface of the sample 4 and continues while the stage 5 is rotating, then the sample 4 and the monochromatic X-ray Since it is considered to be too far away, stage 5 will be raised. Then, the stage 5 is similarly swung at a predetermined angle to find a critical point where the maximum value indicates the energy value before shutoff and where the energy intensity decreases with further elevation or rotation. This state is considered to be a state in which monochromatic X-rays are brought into contact with the optically smooth surface of the sample 4. (0017) Finally, move the stage 5 at a desired angle around an axis perpendicular to the plane of the paper, that is, an axis perpendicular to the monochromatic X-ray irradiation direction and parallel to the optically smooth surface of the sample 4. The setting of the irradiation angle is completed by rotating the irradiation angle counterclockwise by 0.06 degrees (FIG. 4). As this irradiation angle, a critical angle for efficient total reflection is selected. [0018] In this way, According to this embodiment, the stage 5 is rotated after the irradiation direction of the monochromatic X-rays is made parallel to the optically smooth surface of the sample 4, so that the monochromatic X-rays are accurately and reliably applied at the desired angle. can be irradiated onto the optically smooth surface of the sample 4. [0019] FIG. 5 is a block diagram showing a total internal reflection fluorescent X-ray analyzer to which this embodiment is applied. Total internal reflection fluorescent X-ray analyzer In this case, an X-ray generating tube is used as an X-ray source.
The X-rays emitted from the radiation tube 6 are made into a thin parallel X-ray bundle by the slit 7, and then separated into spectra by the X-ray spectrometer 8. As the X-ray spectroscopy means 8, a spectroscopic crystal of lithium fluoride LiF can be used, and by reflecting (diffraction) the X-rays emitted from the X-ray generating tube 6 on its (20,0) plane, Lines can be separated into spectra. The X-rays thus separated are irradiated onto the optically smooth surface of the sample 10 attached to the sample support 9, and the reflected X-rays are incident on the scintillation counter 12 through the slit 11. Since the sample support 9 is fixed to a fine movement stage 13a fixed to the positioning table 13, it can rotate about a direction perpendicular to the plane of the paper, and can move vertically and horizontally. This positioning table 13 is connected to a positioning controller 14, and this positioning controller 14 is connected to a central processing control section 15. Further, the scintillation counter 12 described above is connected to the central processing control section 15, and the scattered X-ray intensity measured by the scintillation counter 12 is input to the central processing control section 15. Based on this input value, a control command is output to the positioning controller 14, and the position of the sample support 9 is controlled. [00201 On the other hand, a semiconductor X-ray detector 16 is arranged above the sample support 9;
6 is connected to the central processing control section 15 via a preamplifier 17, a linear amplifier 18, and a multichannel analyzer 19. Therefore, the detection output of the fluorescent X-rays emitted from the sample 10 placed on the sample support 9 is amplified, extracted as a pulse output with a wave height proportional to the magnitude of the fluorescent X-ray energy, and converted into a digital output. After that, the data is processed by the central processing control section 15. [00211 When setting the irradiation angle of X-rays using this total internal reflection fluorescence X-ray analyzer, first, the X-rays emitted from the X-ray spectrometer 8 are directly transferred to the scintillation counter 12.
and measure its intensity. Next, by controlling the fine movement stage 1'3a with the positioning controller 14, the sample support 9 is tilted with respect to the X-ray, and while maintaining this state, it is brought closer to the X-ray, and finally the X-ray
cut off the line. Thereafter, the fine movement stage 13a is rotated or slightly moved up and down, and the central processing control unit 15 compares the intensity of the X-rays before and after the interruption. By matching these X-ray intensities, the optically smooth surface of the sample 10 attached to the upper surface of the sample support 9 can be made parallel to the X-rays. Next, the fine movement stage 13a is rotated counterclockwise, for example, by 0.06 degrees, which is the incident angle with respect to Si. [0022] As described above, according to the total internal reflection fluorescent X-ray apparatus using this embodiment, the irradiation angle can be easily set on the micron order. Using this device, heavy elements or light elements can be analyzed. [00231 Next, another application example to which this embodiment is applied will be described based on FIG. 6. FIG. 6 shows a schematic diagram in which this embodiment is applied to the dual beam method. This device focuses on the fact that the elements that can be analyzed are uniquely determined by the excitation source, and uses two X-ray beams to expand the range that can be analyzed. Therefore, in this device, the first excitation source 2, such as Mo- and α, enables analysis of heavy elements.
0, a first monochromator 21 that makes the X-ray monochromatic, and a second chromatographer such as W-Lβ1 that enables analysis of light elements.
An excitation source 22 and a second monochromator 23 for monochromating the X-rays are used. In this case, it is possible to construct an analyzer having optimal sensitivity not only for heavy elements but also for light elements. In this case, since the energy intensity detection device can be used in common, first, in order to analyze heavy elements (ca-Zr), the irradiation angle is determined using the method described above using the X-ray excitation source 20 and the first monochromator 21. setting, and then setting the irradiation angle using the method described above using the X-ray excitation source 22 and the second monochromator 23 in order to analyze light elements (S-Zn). [0024] Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, if α is used for Ti- instead of W-Lβ1 as the second excitation source 22, high sensitivity can be maintained for elements from Na to Ca. [00'25]

Since the present invention is constructed as described above, it is possible to easily set the irradiation angle of the energy beam with submicron precision. Furthermore, especially when used in a total reflection fluorescent X-ray analyzer, the irradiation angle can be set using equipment essential for analysis, which is efficient.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing a method for setting an energy beam irradiation angle according to an embodiment of the present invention.

FIG. 2 is a process diagram showing a method for setting an energy beam irradiation angle according to an embodiment of the present invention.

FIG. 3 is a process diagram showing a method for setting an energy beam irradiation angle according to an embodiment of the present invention.

FIG. 4 is a process diagram showing a method for setting an energy beam irradiation angle according to an embodiment of the present invention.

FIG. 5 is a block diagram showing an outline of a total internal reflection fluorescent X-ray analyzer to which the irradiation angle setting method according to the present embodiment can be applied.

FIG. 6 is a schematic diagram showing another device to which the irradiation angle setting method according to the present embodiment can be applied.

[Explanation of symbols]

1... Rotating anticathode type target, 2... Spectroscopic crystal,
3.12... Scintillation counter, 4.10.
...Sample, 5...Stage, 6...X-ray generating tube, 7
．． 11...Slit, 8...X-ray spectroscopy means, 9...
- Sample support, 13... Positioning table, 14...
・Positioning controller, 15... central processing control section,
16...Semiconductor X-ray detector, 17...Preamplifier,
18... Linear amplifier, 19... Multi-channel analyzer, 21... First monochromator, 22...
・Second excitation source, 23...second monochromator: Figure 5]

Claims (1)

[Claims] Claims: 1. A method for setting an energy beam irradiation angle in which a sample placed on a rotatable and movable stage and having an optically smooth surface is irradiated with an energy beam at a predetermined angle, the method comprising: a step of detecting the energy intensity by irradiating the energy beam onto an energy intensity detector; a step of blocking the energy beam by an optically smooth surface of the sample by moving the stage; a step of matching the irradiation direction of the energy beam to an optically smooth surface of the sample by rotating and/or moving the stage while comparing the energy intensity before and after being blocked by the surface; and rotating the stage by the predetermined angle about a rotation axis that is substantially perpendicular to the irradiation direction and parallel to the optically smooth surface of the sample. Setting method.