X-ray diffraction data processing device and X-ray analyzer

Abstract

A peak two-dimensional detection data extraction unit 211 extracts two-dimensional detection data (peak two-dimensional detection data) of the diffracted X-ray Xb with the maximum X-ray intensity, from two-dimensional detection data of diffracted X-rays Xb obtained at a plurality of scanning angles 2θ / θ. Next, a peak position specifying unit 212 specifies the position (peak position) where the X-ray intensity is maximum, from the peak two-dimensional detection data. Then, data processing is performed using positional information on the peak position specified for the peak two-dimensional detection data.

Description

Technical Field

[0001] This invention relates to an X-ray diffraction data processing apparatus for processing two-dimensional detection data of diffracted X-rays obtained at a plurality of scanning angles 2θ / θ using an X-ray analyzer that detects diffracted X-rays diffracted by a sample with a two-dimensional X-ray detector, and an X-ray analyzer using the same apparatus.

Background Art

[0002] Conventionally, in an X-ray analyzer, various adjustments have been made in advance before the start of measurement in order to obtain a desired analysis result. For this reason, there has been a problem that the overall time related to the acquisition of measurement data becomes long. For example, in X-ray analysis called rocking curve measurement, as disclosed in Patent Document 1 and Non-Patent Document 1, it is necessary to adjust the rocking axis (axis alignment adjustment) before the start of measurement so that reciprocal lattice points exist on the scattering plane formed by the incident X-ray and the diffracted X-ray. This is because if the reciprocal lattice points deviate from the scattering plane, the position and width of the diffraction peak detected by the two-dimensional X-ray detector may differ from the actual values, which may reduce the analysis accuracy.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] This invention has been made in view of the problems of the prior art described above, and aims to shorten the overall time involved in acquiring measurement data by improving the processing of measurement data, thereby eliminating the need for various adjustments before the start of measurement. [Means for solving the problem]

[0006] The present invention relates to an X-ray diffraction data processing apparatus that processes two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ by scanning the incident angle θ of the incident X-rays and the angular direction 2θ in which the X-ray detector is positioned, using an X-ray analyzer that irradiates an incident X-ray from an incident angle θ direction to a measurement point set on the surface of a sample, and positions a two-dimensional X-ray detector at an angular direction 2θ with respect to the incident angle θ direction, and detects the diffracted X-rays diffracted by the sample with the two-dimensional X-ray detector, comprising: a peak two-dimensional detection data extraction unit that extracts two-dimensional detection data of the diffracted X-ray with the maximum X-ray intensity (peak two-dimensional detection data) from the two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ; a peak position identification unit that identifies the position (peak position) where the X-ray intensity is maximum from the peak two-dimensional detection data; and a data processing unit that performs data processing using the position information of the peak position identified for the peak two-dimensional detection data.

[0007] Furthermore, in the X-ray diffraction data processing apparatus according to the present invention, the data processing unit is characterized by including a target area setting unit that sets a target area surrounding the peak position, and a profile generation unit that integrates the X-ray intensity in the area corresponding to the target area for each two-dimensional detection data of diffracted X-rays obtained at the plurality of scanning angles 2θ / θ, and creates a rocking curve profile based on the X-ray intensity integrated for each of these two-dimensional detection data.

[0008] Furthermore, in the X-ray diffraction data processing apparatus according to the present invention, the two-dimensional X-ray detector has a detection surface for detecting diffracted X-rays, and a reference detection point is set in advance on the detection surface, and when incident X-rays are irradiated onto the surface of a symmetrically reflecting sample from the direction of incident angle θ, the optical axis of the diffracted X-rays appearing from the surface of the sample in the direction of diffraction angle 2θ is arranged to be incident on the reference detection point, and the peak position identification unit is configured to determine the offset amount between the peak position recorded in the two-dimensional peak detection data and the reference detection point.

[0009] Here, the peak position identification unit is characterized by determining the following Δω and Δχ as the offset amount between the peak position and the reference detection point. Δω: Offset amount along the trajectory ω of the reference detection point during 2θ / θ scanning. Δχ: Offset amount along the circular arc trajectory χ centered on the reference detection point at a scanning angle of 2θ / θ = 0°.

[0010] Furthermore, in the X-ray diffraction data processing apparatus according to the present invention, the target area setting unit is characterized by having a function to arbitrarily adjust the width of the target area surrounding the peak position that corresponds to the angular direction of 2θ.

[0011] Furthermore, in the X-ray diffraction data processing apparatus according to the present invention, the data processing unit includes a peak shift amount calculation unit that calculates the shift amount of the scanning angle 2θ / θ by comparing the scanning angle 2θ / θ of the two-dimensional peak detection data acquired for a plurality of measurement points on a straight line set on the surface of a flat plate-shaped sample with the scanning angle 2θ / θ of the sample, and a radius of curvature calculation unit that calculates the radius of curvature of the crystal lattice plane of the sample based on the shift amount of the scanning angle 2θ / θ obtained by the peak shift amount calculation unit.

[0012] Next, the present invention relates to an X-ray analysis apparatus that irradiates a measurement point set on the surface of a sample with incident X-rays from a direction of incident angle θ, and arranges a two-dimensional X-ray detector in an angular direction of 2θ with respect to the direction of the incident angle θ, and detects the diffracted X-rays diffracted by the sample with the two-dimensional X-ray detector, and is characterized by comprising an X-ray diffraction data processing apparatus having the above-described configuration.

[0013] Furthermore, the X-ray analyzer according to the present invention comprises a height-adjustable sample stage for placing the sample, and a sample stage control unit having at least the function of controlling the height of the sample stage, wherein the sample stage control unit is configured to adjust the height of the sample stage based on the peak position of the two-dimensional peak detection data.

[0014] Furthermore, in the X-ray analyzer according to the present invention, the X-ray diffraction data processing device includes a storage unit that stores the peak position (reference height peak position) for the two-dimensional peak detection data obtained by placing the sample at a reference height, with the measurement point set on the surface of the sample being positioned at the irradiation point of the incident X-rays, and the state in which the measurement point is positioned at the reference height of the sample is used as the reference height of the sample; and a height shift amount calculation unit that compares the peak position in the two-dimensional peak detection data obtained by placing the sample at an arbitrary height position with the reference height peak position to determine the amount of positional shift between them, and calculates the amount of shift of the arbitrary height position relative to the reference height based on the amount of positional shift; and the sample stage control unit is configured to move the sample placed at the arbitrary height position to the reference height based on the amount of shift of the arbitrary height position calculated by the height shift amount calculation unit.

[0015] Next, the present invention relates to an X-ray diffraction data processing method, which is performed by an X-ray diffraction data processing device for scanning the incident angle θ of the incident X-rays and the angular direction 2θ in which the X-ray detector is positioned, and processing two-dimensional detection data of diffracted X-rays obtained at a plurality of scanning angles 2θ / θ, in an X-ray analyzer that irradiates an incident X-ray from an incident angle θ direction to a measurement point set on the surface of a sample, and positions a two-dimensional X-ray detector at an angular direction 2θ with respect to the incident angle θ direction, and detects the diffracted X-rays diffracted by the sample with the two-dimensional X-ray detector, and is characterized by comprising: a peak two-dimensional detection data extraction step of extracting two-dimensional detection data of the diffracted X-ray with the maximum X-ray intensity (peak two-dimensional detection data) from the two-dimensional detection data of diffracted X-rays obtained at a plurality of scanning angles 2θ / θ; a peak position identification step of identifying the position (peak position) where the X-ray intensity is maximum from the peak two-dimensional detection data; and a data processing step of performing data processing using the position information of the peak position identified for the peak two-dimensional detection data.

[0016] Furthermore, the present invention relates to an X-ray diffraction data processing program, which is executed by an X-ray diffraction data processing device for scanning the incident angle θ of the incident X-rays and the angular direction 2θ in which the X-ray detector is positioned, and for processing two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ, in an X-ray analysis device that irradiates an incident X-ray from an incident angle θ direction to a measurement point set on the surface of a sample, and positions a two-dimensional X-ray detector at an angular direction of 2θ with respect to the incident angle θ direction, and detects the diffracted X-rays diffracted by the sample with the two-dimensional X-ray detector, and includes: a peak two-dimensional detection data extraction step for extracting two-dimensional detection data of the diffracted X-ray with the maximum X-ray intensity (peak two-dimensional detection data) from the two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ; a peak position identification step for identifying the position (peak position) where the X-ray intensity is maximum from the peak two-dimensional detection data; and a data processing step for executing data processing using the position information of the peak position identified for the peak two-dimensional detection data. [Brief explanation of the drawing]

[0017] [Figure 1] FIG. 1A is a schematic diagram showing the operation of an X-ray diffractometer when performing a rocking curve measurement on a thin film substrate sample. FIG. 1B is a graph showing information on the thin film substrate sample analyzed from the rocking curve profile. [Figure 2] FIG. 2 is an overall configuration diagram showing an overview of the X-ray analyzer according to an embodiment of the present invention. [Figure 3] FIG. 3 is a block diagram showing the functional configuration of an X-ray diffraction data processing device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram for explaining the function of the peak two-dimensional detection data extraction unit. [Figure 5] FIG. 5A is a front view showing an enlarged two-dimensional image of peak two-dimensional detection data for explaining the function of the peak position specifying unit. FIG. 5B is a front view showing an enlarged two-dimensional image of peak two-dimensional detection data for explaining the function of the target area setting unit. [Figure 6] FIG. 6A is a front sectional view depicting the surface of the sample and the crystal lattice plane for explaining the relationship between the position of the diffracted X-ray recorded in the two-dimensional detection data, the surface of the sample, and the crystal lattice plane. FIG. 6B is a sectional perspective view of the same. [Figure 7] FIG. 7 is a principle diagram for explaining the relationship between the position of the diffracted X-ray recorded in the two-dimensional detection data, the surface of the sample, and the crystal lattice plane. [Figure 8] FIG. 8 is a front view showing the offset amount between the detection position of the diffracted X-ray diffracted by the asymmetric reflection sample and the reference detection point in the two-dimensional image of the two-dimensional detection data. [Figure 9] FIG. 9 is a diagram for explaining the function of creating a rocking curve profile by the target area setting unit and the profile generation unit. [Figure 10] FIGS. 10-A1, 10-A2, 10-B1, 10-B2, 10-C1, and 10-C2 are diagrams for explaining the light receiving slit function of the target area setting unit, respectively. [Figure 11] FIG. 11 is a flowchart for explaining a method of creating a rocking curve profile. [Figure 12] FIG. 12A is a front view of a thin film substrate sample for explaining the function of a data processing unit for evaluating the warp of a sample. FIG. 12B is a cross-sectional front view thereof. [Figure 13] FIG. 13A is an example of a graph in which peak values of diffracted X-ray Xb intensities for each measurement point are arranged and displayed along the peak angle for explaining the function of a data processing unit for evaluating the warp of a sample. FIG. 13B is an example of a graph showing the relationship between the peak angle and the positions of each measurement point for explaining the function of a data processing unit for evaluating the warp of a sample. [Figure 14] FIG. 14 is a schematic diagram for explaining the function of a data processing unit for adjusting the sample height.

Description of Reference Numerals

[0018] 10: X-ray image, 20: target region, 100: X-ray diffractometer, 101: control unit, 110: sample stage, 120: X-ray source, 121: X-ray irradiation unit, 130: two-dimensional X-ray detector, 140: goniometer, 141: θ arm, 142: 2θ arm, 200: X-ray diffraction data processing device, 201: input / output unit, 202: storage unit, 210: preprocessing unit for two-dimensional detection data, 211: peak two-dimensional detection data extraction unit, 212: peak position determination unit, 220: data processing unit for creating a rocking curve profile, 221: target region setting unit, 222: profile generation unit, 230: data processing unit for evaluating the warp of a sample, 231: peak shift amount calculation unit, 232: radius of curvature calculation unit, 240: data processing unit for adjusting the sample height, 241: peak position offset amount calculation unit, 242: height deviation amount calculation unit

Best Mode for Carrying Out the Invention

[0019] Embodiments of this invention will be described in detail below with reference to the drawings. In this embodiment, we will describe an example configuration in which the present invention is applied to an X-ray analyzer used to analyze the thickness and composition of a thin film by rocking curve measurement, using a thin film substrate such as a semiconductor wafer on which a thin film crystal has been deposited as a sample.

[0020] [Overview of rocking curve measurement for thin film substrate samples] First, with reference to Figures 1A and 1B, we will explain the overview of X-ray analysis using rocking curve measurement for thin film substrate samples. Figure 1A is a schematic diagram showing the operation of an X-ray diffractometer when performing rocking curve measurements. As shown in the figure, incident X-rays Xa are irradiated onto the surface of a thin film substrate sample (hereinafter sometimes simply referred to as the sample) S at an incident angle θ, and diffracted X-rays Xb that appear in the direction of diffraction angle 2θ with respect to the optical axis of the incident X-rays Xa are detected by the X-ray detector 1 (X-ray diffraction measurement). In rocking curve measurement, the X-ray detector 1 is moved in the direction of the diffraction angle 2θ while changing the incident angle θ of the incident X-ray Xa on the surface of the sample S, and X-ray diffraction measurements are repeated at multiple scanning angles 2θ / θ.

[0021] Then, based on the diffracted X-ray intensity obtained at each scanning angle of 2θ / θ, a rocking curve profile is created as shown in Figure 1B. This rocking curve profile is a graph of the detection data obtained from the rocking curve measurement described above, with the horizontal axis representing the scanning angle 2θ / θ and the vertical axis representing the diffracted X-ray intensity.

[0022] From the rocking curve profile in Figure 1B, for example, the composition of the material constituting the thin film substrate sample S can be determined from the peak values ​​Pa and Pb of the diffracted X-ray intensity, and the film thickness of the thin film substrate sample S can be determined from the period L of the amplitude F, called the fringe, that appears around the peak value.

[0023] [Overview of X-ray analyzer] Figure 2 is an overall configuration diagram showing the overview of the X-ray analyzer according to this embodiment. The X-ray analyzer consists of an X-ray diffractometer 100 for performing X-ray diffraction measurements and acquiring measurement data, and an X-ray diffraction data processing device 200 for processing the measurement data acquired by the X-ray diffractometer 100.

[0024] The operation of the X-ray diffractometer 100 is controlled by a control unit 101. This control unit 101 is, for example, a computer with a dedicated control program installed. Similarly, the X-ray diffraction data processing device 200 is also, for example, a computer with a dedicated X-ray diffraction data processing program installed.

[0025] The X-ray diffractometer 100 includes a sample stage 110 for placing a sample S, an X-ray source 120 and an X-ray irradiation unit 121 for irradiating the surface of the sample S with X-rays, and a two-dimensional X-ray detector 130 for detecting diffracted X-rays Xb diffracted by the sample S.

[0026] The sample stage 110 used in this embodiment is equipped with a mechanism that can move at least vertically (Z direction) to adjust the height position of the sample S. Here, the control unit 101 also functions as a sample stage control unit, as will be described later, and controls the height of the sample stage 110 based on the processing data regarding the height displacement of the sample S output from the X-ray diffraction data processing device 200.

[0027] Furthermore, the X-ray irradiation unit 121 includes an X-ray mirror or monochromator that extracts and monochromatizes / parallels only X-rays of a specific wavelength from the X-rays emitted from the X-ray source 120, and a collimator that limits the beam diameter of the monochromatized X-rays. The X-ray irradiation unit 121 is configured by combining various known X-ray optical components (e.g., monochromators, collimators, various slits, etc.) depending on the measurement purpose. The two-dimensional X-ray detector 130 has the function of detecting the intensity and incident position of X-rays incident on the detection surface.

[0028] In this embodiment, the X-ray source 120 and the X-ray irradiation unit 121 are mounted on the θ arm 141 of the goniometer 140, and the two-dimensional X-ray detector 130 is mounted on the 2θ arm 142 of the goniometer 140. The X-ray source 120 and the X-ray irradiation unit 121 and the two-dimensional X-ray detector 130 are configured to rotate with respect to the surface of the horizontally positioned sample S while maintaining the θ-2θ relationship. That is, according to Bragg's law, as shown in Figure 2, when X-rays are irradiated onto the surface of the sample S at an incident angle θ, diffracted X-rays Xb appear in the direction of a diffraction angle 2θ with respect to the optical axis of the incident X-rays Xa. Therefore, the goniometer 140 drives the θ arm 141 and the 2θ arm 142 so that the X-ray source 120 and the X-ray irradiation unit 121 are positioned to irradiate the measurement point set on the surface of the sample S from the direction of the incident angle θ, and the two-dimensional X-ray detector 130 is positioned in the direction of the diffraction angle 2θ with respect to the optical axis of the incident X-ray Xa.

[0029] Alternatively, the X-ray source 120 and the X-ray irradiation unit 121 can be fixed in place, and the sample stage 110 can be rotated relative to the incident X-ray Xa to tilt the surface of the sample S, thereby irradiating the surface of the sample S with X-rays from the direction of the incident angle θ.

[0030] In this embodiment, the X-ray diffractometer 100 with the above configuration is operated to scan the incident angle θ of the incident X-ray Xa and the angular direction 2θ in which the two-dimensional X-ray detector 130 is positioned, and two-dimensional detection data of diffracted X-rays Xb is acquired at multiple scanning angles 2θ / θ. This two-dimensional detection data of diffracted X-rays Xb is output from the two-dimensional X-ray detector 130, converted into two-dimensional image data corresponding to the detection surface of the two-dimensional X-ray detector 130, and stored in the X-ray diffraction data processing device 200. Therefore, the two-dimensional detection data is converted into two-dimensional image data corresponding to the detection surface of the two-dimensional X-ray detector 130, and data processing is performed in this converted state.

[0031] [Functional configuration of X-ray diffraction data processing device] Figure 3 is a block diagram showing the functional configuration of the X-ray diffraction data processing apparatus according to this embodiment. Each functional unit shown in the figure consists, for example, of the computer hardware described above and a dedicated X-ray diffraction data processing program installed on the computer.

[0032] The X-ray diffraction data processing device 200 includes an input / output unit 201, a storage unit 202, a preprocessing unit 210 for two-dimensional detection data, and a data processing unit for processing the two-dimensional detection data according to the purpose. The input / output unit 201 is connected to the two-dimensional X-ray detector 130 and the control unit 101 of the X-ray diffractometer 100, and is a functional unit that performs data input and output with these devices. Although not shown in the figure, a display device such as a liquid crystal display and an input device such as a keyboard are also connected to the X-ray diffraction data processing device 200 via the input / output unit 201.

[0033] The memory unit 202 is a functional unit for storing various types of data. Two-dimensional detection data of diffracted X-rays Xb output from the two-dimensional X-ray detector 130 of the X-ray diffractometer 100 is stored in the memory unit 202 via the input / output unit 201. The memory unit 202 also has various types of information necessary for data processing pre-stored, such as information about the X-ray diffractometer 100 and information about the sample S. Furthermore, data processed by each functional unit of the X-ray diffraction data processing device 200 is also stored in the memory unit 202 as appropriate. Then, each functional unit of the X-ray diffraction data processing device 200 reads the data stored in the storage unit 202 as appropriate and performs processing.

[0034] In this embodiment, the data processing unit is configured by dividing it into three functional units: a data processing unit 220 for creating a rocking curve profile, a data processing unit 230 for evaluating the curvature of the sample, and a data processing unit 240 for adjusting the sample height. The functions of the two-dimensional detection data preprocessing unit 210 and each data processing unit are described in the following sections.

[0035] [Preprocessing step for two-dimensional detection data] The preprocessing unit 210 for two-dimensional detection data includes the functional units of a peak two-dimensional detection data extraction unit 211 and a peak position identification unit 212. The peak two-dimensional detection data extraction unit 211 extracts the two-dimensional detection data (peak two-dimensional detection data) of the diffracted X-ray Xb with the maximum X-ray intensity from the two-dimensional detection data of diffracted X-ray Xb obtained at multiple scanning angles 2θ / θ.

[0036] Specifically, the peak two-dimensional detection data extraction unit 211 first reads the two-dimensional detection data (two-dimensional image data) of diffracted X-rays Xb stored in the storage unit 202, and calculates the total intensity of the X-rays recorded in each two-dimensional detection data (total X-ray intensity). Then, it compares the total X-ray intensities of each two-dimensional detection data and extracts the two-dimensional detection data with the maximum total X-ray intensity as the peak two-dimensional detection data. In addition to diffracted X-rays Xb from the sample S, scattered X-rays and other radiation also enter the detection surface of the two-dimensional X-ray detector 130. However, the total X-ray intensity is calculated by including all of these X-rays that are included in the two-dimensional detection data.

[0037] For example, in the multiple two-dimensional detection data (data Nos. 290, 310, 320, 330, and 340) shown in Figure 4, an X-ray image 10 is recorded in each two-dimensional image, and the intensity of the X-ray can be determined from the color intensity of the X-ray image 10. The following explanation will proceed assuming that the multiple two-dimensional detection data shown in Figure 4 are two-dimensional detection data detected at the scanning angle 2θ / θ shown in the same figure.

[0038] As shown in the graph in Figure 4, by sequentially plotting the total X-ray intensity of each two-dimensional detection data in order of data number and creating an intensity graph of diffracted X-rays (Xb), it is possible to visually extract peak two-dimensional detection data. In the example shown in Figure 4, the two-dimensional detection data for data No. 320 is extracted as the peak two-dimensional detection data because it represents the highest total X-ray intensity recorded across the entire area of ​​the two-dimensional image.

[0039] Next, the peak position identification unit 212 identifies the position (peak position) where the X-ray intensity is maximum from the two-dimensional peak detection data. For example, in the two-dimensional image of the peak two-dimensional detection data for data No. 320, shown in an enlarged view in Figure 5A, an X-ray image 10 is recorded slightly to the upper right of the center. The position of this X-ray image 10 is identified as the peak position. The method of position identification will be described later with reference to Figure 8.

[0040] Here, the relationship between the position of the diffracted X-ray Xb recorded in the two-dimensional detection data and the surface and crystal lattice plane Sa of the sample S will be explained with reference to Figures 6A to 7. As shown in Figure 6A, if the crystal lattice planes Sa inside the sample S are aligned parallel to the surface of the sample S, when incident X-rays Xa are incident on the crystal lattice plane Sa at an angle θa and diffracted X-rays Xb are reflected in the symmetrical angular direction (θa), similarly, diffracted X-rays Xb appear on the surface of the sample S in the angular direction (θa) symmetric to the incident angle θa of the incident X-rays Xa. This is called symmetric reflection.

[0041] On the other hand, as shown in Figure 6B, if the crystal lattice planes Sa located inside the sample S are aligned with the surface of the sample S at an angle, then as shown in Figure 6C, when incident X-rays Xa are incident on the crystal lattice plane Sa at an angle θa and diffracted X-rays Xb are reflected in a symmetrical angular direction (θa), the diffracted X-rays Xb appear on the surface of the sample S in an angular direction (θc) that is asymmetric to the angle of incidence of the incident X-rays Xa (θb) and the angular direction (θc) in which the diffracted X-rays Xb appear. This is called asymmetric reflection.

[0042] Generally, the X-ray diffractometer 100 is based on symmetrical reflection and, as shown in Figure 7, irradiates the surface of the sample S with incident X-rays Xa from the direction of incident angle θ, and a two-dimensional X-ray detector 130 is positioned at an angle of 2θ with respect to the direction of incident angle θ, and the diffracted X-rays Xb diffracted by the sample S are detected by the two-dimensional X-ray detector 130. The X-ray diffractometer 100 of this embodiment shown in Figure 2 has a similar configuration. As shown in Figure 6A, the sample S is usually placed on the sample stage 110 with the horizontal plane as the reference plane, so that its surface is horizontal, but this is not the only option.

[0043] The two-dimensional X-ray detector 130 is adjusted so that diffracted X-rays Xb appearing from the surface of the sample S in the direction of diffraction angle 2θ are incident on a reference detection point P0 (usually the center position) that has been set in advance on the detection surface. Therefore, in a sample S exhibiting asymmetric reflection, where the crystal lattice planes Sa are aligned with the surface of the sample S at an angle, the diffracted X-rays Xb will be incident at a position P1 shifted from the reference detection point P0, as shown in Figure 7.

[0044] Figure 8 is a front view showing the offset amount between the detection position of the diffracted X-ray Xb diffracted by the asymmetrically reflected sample S and the reference detection point P0 in a two-dimensional image of the two-dimensional detection data. In this embodiment, the peak position identification unit 212 shown in Figure 3 identifies the peak position (the position where the X-ray image 10 is stored) recorded in the two-dimensional image of the peak two-dimensional detection data using offset amounts Δω and Δχ between it and the reference detection point P0.

[0045] Here, Δω is the offset amount along the trajectory ω traced by the reference detection point P0 set on the detection surface of the two-dimensional X-ray detector 130 when the X-ray diffractometer 100 performs a 2θ / θ scan, as shown in Figure 7. In simpler terms, it is the offset amount along the trajectory ω of the reference detection point P0 during a 2θ / θ scan. Furthermore, Δχ is the offset amount along the circular arc trajectory χ centered on position P2 (i.e., the reference detection point P0 at a scanning angle of 2θ / θ=0°) where the incident X-ray Xa directly enters the detection surface of the two-dimensional X-ray detector 130 at a scanning angle of 2θ / θ=0°.

[0046] In rocking curve measurements, if diffracted X-rays Xb are incident at a position offset from the reference detection point P0 of the two-dimensional X-ray detector 130, the position and width of the diffraction peak detected by the two-dimensional X-ray detector 130 may differ from the actual values, potentially reducing the accuracy of the analysis. Therefore, conventionally, prior to measurement, adjustments (axial adjustment) were performed by rotating the sample S around the ω-axis or χ-axis as shown in Figure 7 to tilt the surface of the sample S so that the diffracted X-rays Xb were incident at the reference detection point P0.

[0047] After this axis alignment adjustment, the diffracted X-ray Xb that was incident at the detection position shown in Figure 8 is now incident at the reference detection point P0, so the diffracted X-ray Xb is detected at an angle where the scanning angle 2θ / θ has shifted by Δω. Therefore, the two-dimensional detection data of the diffracted X-ray Xb with maximum X-ray intensity (peak two-dimensional detection data) will also be detected at a scanning angle 2θ / θ that has shifted by Δω after the axis alignment adjustment.

[0048] Therefore, in the X-ray analyzer of this embodiment, which does not perform axis alignment adjustment, by processing the data while taking into account the offset amount Δω of the scanning angle 2θ / θ from which the two-dimensional detection data was acquired, it is possible to perform data analysis with the same high accuracy as that of an X-ray analyzer with axis alignment adjustment. Furthermore, since no axis adjustment is required, the time involved in acquiring measurement data can be significantly reduced.

[0049] [Data processing unit for creating rocking curve profiles] Next, the data processing unit 220 for creating a rocking curve profile, shown in Figure 3, will be described. The rocking curve profile creation data processing unit 220 includes a target area setting unit 221 and a profile generation unit 222.

[0050] The target area setting unit 221 has the function of setting a target area 20 that surrounds the peak position. In other words, as shown in Figure 5B, an X-ray image 10 is recorded in the two-dimensional image of the peak two-dimensional detection data. The position where this X-ray image 10 is recorded is the peak position. The target area setting unit 221 sets a target area 20 of any size to surround this peak position based on instruction information from the operator input via an input device such as a keyboard.

[0051] In this embodiment, the target area 20 is defined as a sector-shaped area centered on the reference detection point P0 (position P2 in the figure) at the scanning angle 2θ / θ=0° described above, with a sector width ΔA and a length ΔB. However, the shape and size of the target area 20 are not limited to these.

[0052] Next, the profile generation unit 222 integrates the X-ray intensity within the region corresponding to the target region 20 for each two-dimensional detection data of diffracted X-rays Xb obtained at multiple scanning angles 2θ / θ, and creates a rocking curve profile based on the X-ray intensity integrated for each of these two-dimensional detection data.

[0053] Figure 9 is a diagram illustrating the function of creating a rocking curve profile using the target area setting unit and the profile generation unit. For example, with respect to the two-dimensional images of multiple two-dimensional detection data shown in Figure 4, the target area setting unit 221 first sets a target area 20 for the two-dimensional image of the peak two-dimensional detection data (data No. 320). Next, the profile generation unit 222 integrates the X-ray intensity within this target area 20 and plots the integrated X-ray intensity on the rocking curve profile graph.

[0054] Here, the scanning angle 2θ / θ from which the peak two-dimensional detection data (data No. 320) was acquired was 32.0°. By adding the previously described peak position offset amount Δω to this scanning angle 2θ / θ at the time of measurement, (2θ / θ)±Δω is defined as the scanning angle for the peak two-dimensional detection data (data No. 320). That is, the X-ray intensity of the peak two-dimensional detection data (data No. 320) is plotted against this scanning angle of (2θ / θ)±Δω. By processing the data in this way, it is possible to create a highly accurate rocking curve profile equivalent to that of a frame with proper axis alignment.

[0055] The target area setting unit 221 sets target areas 20 for the two-dimensional images of other two-dimensional detection data (data Nos. 290, 310, 330, 340) at positions corresponding to the target area 20 set for the two-dimensional image of the peak two-dimensional detection data (data No. 320). Then, for each two-dimensional detection data (data Nos. 290, 310, 330, 340), the profile generation unit 222 integrates the X-ray intensity within the target area 20 and plots the integrated X-ray intensity on the rocking curve profile graph. At this time as well, the offset amount Δω is taken into account, and (2θ / θ)±Δω is set as the scanning angle for each two-dimensional detection data (data Nos. 290, 310, 330, 340).

[0056] For all two-dimensional detection data obtained by X-ray diffraction measurement, a target region 20 is set using the procedure described above, the X-ray intensity within that target region 20 is integrated, and the integrated X-ray intensity is plotted on the rocking curve profile graph. This creates a rocking curve profile as shown in Figure 9.

[0057] The peak position offset amounts Δω and Δχ obtained in the rocking curve profile creation procedure described above are parameters of the inclination of the crystal lattice plane with respect to the surface, and these values ​​themselves can also be used to evaluate single crystal substrates. Some single-crystal substrates, such as gallium arsenide (GaAs) substrates and silicon carbide (SiC) substrates, are cut so that specific crystal lattice planes are at a predetermined inclination angle with respect to the surface. Conventionally, for these single-crystal substrates, the procedure involved repeatedly performing an ω scan at each scanning angle of 2θ / θ to determine Δω, and then performing a χ scan to determine Δχ. In contrast, with the X-ray diffraction data processing device according to this embodiment, if only a 2θ / θ scan is performed, Δω and Δχ can also be obtained in the process of creating the rocking curve, making it possible to quickly evaluate the offset amount.

[0058] Figures 10-A1 to 10-C2 are diagrams illustrating the light-receiving slit function of the target area setting unit. The target area setting unit 221 has a light-receiving slit function that arbitrarily adjusts the width of the target area 20 surrounding the peak position, corresponding to the direction of the scanning angle 2θ. As shown in Figure 5B, increasing or decreasing the width ΔA of the target area 20, which is set in a sector shape centered on the reference detection point P0 (position P2 in the figure), is equivalent to increasing or decreasing the width in the scanning angle 2θ direction. Furthermore, the target area 20 set in the two-dimensional image of the two-dimensional detection data has the function of limiting the X-rays for which the X-ray intensity is calculated, similar to the light-receiving slit placed in front of the two-dimensional X-ray detector 130 in the X-ray diffractometer 100. Increasing or decreasing the width ΔA of the target area 20 has the same effect as increasing or decreasing the width of the light-receiving slit.

[0059] For example, as shown in Figure 10-A1, if the target region 20 is set to a wide width ΔA1, a rocking curve profile with low resolution is created, as shown in Figure 10-A2. Then, as shown in Figure 10-B1, if the target region 20 is set to a narrow width ΔA2, a rocking curve profile with improved resolution is created, as shown in Figure 10-B2. As shown in Figure 10-C1, if the target region 20 is set to an even narrower width ΔA3, a rocking curve profile with even higher resolution can be created, as shown in Figure 10-C2. In this way, by narrowing the width of the target region 20 within the range that includes the diffracted X-rays Xb reflected from the sample S, a high resolution equivalent to that obtained by narrowing the width of the light-receiving slit can be obtained. Furthermore, by arbitrarily adjusting the length ΔB of the target area 20 (the length corresponding to the direction perpendicular to the width in the scanning angle 2θ direction), it is possible to achieve the same function as a light-receiving vertical limiting slit.

[0060] [How to create a rocking curve profile] Next, we will explain how to create a rocking curve profile, referring to Figure 11. First, the control unit 101 shown in Figure 2 controls each component of the X-ray diffractometer 100 to scan the sample S with respect to the incident angle θ of the incident X-ray Xa and the angular direction 2θ in which the two-dimensional X-ray detector 130 is positioned, and acquires two-dimensional detection data of diffracted X-rays Xb at multiple scanning angles 2θ / θ. This two-dimensional detection data of diffracted X-rays Xb is output from the two-dimensional X-ray detector 130, converted into two-dimensional image data corresponding to the detection surface of the two-dimensional X-ray detector 130, and stored in the storage unit 202 of the X-ray diffraction data processing device 200 (step S1). In the rocking curve profile creation method of this embodiment, two-dimensional detection data of diffracted X-rays Xb can be acquired successively at multiple scanning angles 2θ / θ without performing axis adjustment, thereby significantly reducing the measurement time required to acquire the two-dimensional detection data.

[0061] The X-ray diffraction data processing device 200 performs the rocking curve profile creation process in the following steps, based on a dedicated X-ray diffraction data processing program. First, the peak two-dimensional detection data extraction unit 211 reads two-dimensional detection data of diffracted X-rays Xb acquired at multiple scanning angles 2θ / θ from the storage unit 202 and calculates the total intensity of the X-rays recorded in each two-dimensional detection data (total X-ray intensity). Then, it compares the total X-ray intensities of each two-dimensional detection data and extracts the two-dimensional detection data with the maximum total X-ray intensity as the peak two-dimensional detection data (step S2). In the example shown in Figure 4, the two-dimensional detection data for data No. 320 is extracted as the peak two-dimensional detection data because it represents the highest total X-ray intensity recorded across the entire area of ​​the two-dimensional image.

[0062] Next, the peak position identification unit 212 identifies the position where the X-ray intensity is maximum (peak position) from the two-dimensional peak detection data (step S3). In this embodiment, as described above, the peak position recorded in the two-dimensional image of the two-dimensional peak detection data (the position where the X-ray image 10 is stored) is identified by the offset amounts Δω and Δχ between it and the reference detection point P0 (see Figure 8).

[0063] Next, the target area setting unit 221 sets a target area 20 of any size to surround the peak position based on instruction information from the operator input via an input device such as a keyboard (see Figure 5B, step S4).

[0064] Then, the profile generation unit 222 integrates the X-ray intensity within the region corresponding to the target region 20 for each two-dimensional detection data of diffracted X-rays Xb obtained at multiple scanning angles 2θ / θ, and creates a rocking curve profile based on the X-ray intensity integrated for each of these two-dimensional detection data (see Figure 9, step S5). The specific processing at this time is as described above, and the scanning angle of the two-dimensional detection data is set to (2θ / θ)±Δω by adding an offset amount Δω to the scanning angle 2θ / θ at the time of measurement.

[0065] [Data processing unit for evaluating sample warpage] Next, the data processing unit 230 for evaluating the warpage of the sample shown in Figure 3 will be explained with reference to Figures 12A to 13B. The data processing unit 230 for evaluating the warpage of the sample includes the functional units of a peak shift amount calculation unit 231 and a radius of curvature calculation unit 232 (see Figure 3).

[0066] As shown in Figure 12A, the operator sets multiple measurement points X1 to X9 linearly on the surface of the thin film substrate sample S, and performs rocking curve measurements for these multiple measurement points. The two-dimensional detection data for each scanning angle 2θ / θ obtained by rocking curve measurement at the measurement point is stored in the storage unit 202. Furthermore, from this two-dimensional detection data, the peak two-dimensional detection data extraction unit 211 extracts the two-dimensional detection data (peak two-dimensional detection data) of the diffracted X-ray Xb which has the maximum X-ray intensity.

[0067] The peak shift amount calculation unit 231 compares the scanning angles 2θ / θ of the two-dimensional peak detection data acquired for each measurement point X1 to X9 to determine the shift amount of the scanning angle 2θ / θ. In other words, if the thin film substrate sample S is warped, the crystal lattice plane Sa will tilt, as shown in Figure 12B, for example, and the angular direction in which diffracted X-rays Xb appear will change. Therefore, the scanning angle 2θ / θ of the peak two-dimensional detection data shifts according to the inclination of the crystal lattice plane Sa (i.e., the angle of warping). The peak shift amount calculation unit 231 compares the scanning angle 2θ / θ (hereinafter sometimes abbreviated as peak angle) of the two-dimensional peak detection data at each measurement point X1 to X9 and calculates the shift amount.

[0068] Figure 13A is an example of a graph showing the peak values ​​of the diffracted X-ray Xb intensity for each measurement point, arranged along the peak angle, while Figure 13B is an example of a graph showing the relationship between the peak angle and the position of each measurement point. If the thin-film substrate sample S is warped, the peak angle, which indicates the peak value of the diffracted X-ray Xb intensity at each measurement point, will shift laterally, as shown in Figure 13A. Then, as shown in Figure 13B, the peak angle will shift linearly with respect to each measurement point.

[0069] The radius of curvature calculation unit 232 calculates the radius of curvature of the crystal lattice plane of the thin film substrate sample S based on the peak angle shift amount obtained by the peak shift amount calculation unit 231. Specifically, the radius of curvature of the crystal lattice plane of the thin film substrate sample S can be determined from the slope (b / a) of the straight line shown in the graph in Figure 13B.

[0070] [Data processing unit and sample stage control unit for sample height adjustment] Next, we will explain the functions of the sample height adjustment data processing unit 240 shown in Figure 3 and the control unit 101 shown in Figure 2 as sample stage control units. Returning to Figure 3, the memory unit 202 has in advance stored the reference height position where the surface of the sample S should be positioned in the X-ray diffractometer 100. Typically, this reference height position is set to the height of the rotation center of the goniometer 140. Furthermore, the memory unit 202 also has in advance stored the peak position of the two-dimensional peak detection data when the surface of the sample S is at the reference height position.

[0071] The operator performs a rocking curve measurement. The two-dimensional detection data for each scanning angle 2θ / θ obtained by rocking curve measurement is stored in the storage unit 202. Furthermore, from this two-dimensional detection data, the peak two-dimensional detection data extraction unit 211 extracts the two-dimensional detection data (peak two-dimensional detection data) of the diffracted X-ray Xb which has the maximum X-ray intensity. Subsequently, the peak position identification unit 212 identifies the position (peak position) where the X-ray intensity is maximum in the peak two-dimensional detection data.

[0072] Figure 14 is a schematic diagram showing the relationship between the change in sample height S and the amount of shift in the peak position in the two-dimensional peak detection data. Assume that the surface height of sample S during rocking curve measurement is, for example, H1 in Figure 14, and the peak position of the two-dimensional peak detection data obtained by rocking curve measurement is at position P1 on the detection surface of the two-dimensional X-ray detector 130. On the other hand, the reference height position is, for example, H0 in Figure 14, and the peak position of the two-dimensional peak detection data when the surface of the sample S is at this reference height position H0 is assumed to be at position P0 on the detection surface of the two-dimensional X-ray detector 130.

[0073] As shown in Figure 3, the sample height adjustment data processing unit 240 of the X-ray diffraction data processing device 200 includes the functional units of a peak position offset amount calculation unit 241 and a height displacement amount calculation unit 242. The peak position offset amount calculation unit 241 calculates the offset amount D of the peak position d1 of the two-dimensional peak detection data obtained by rocking curve measurement, relative to the peak position d0 of the two-dimensional peak detection data when the surface of the sample S is at this reference height position H0.

[0074] In Figure 14, if the incident angle θ1 of the incident X-ray Xa on the surface of sample S, the diffraction angle θ2 of the diffracted X-ray Xb on the surface of sample S, and the offset amount D are known, the amount of deviation (height deviation) Z of the surface height H1 of sample S during rocking curve measurement, relative to the reference height position H0, can be calculated from the following equation (1). This calculation is performed by the height deviation amount calculation unit 242.

[0075]

number

[0076] The control unit 101 shown in Figure 2 also functions as a sample stage control unit that controls the height of the sample stage 110. In other words, the control unit 101 adjusts the movement of the sample S so that its surface height is the reference height, based on the height displacement amount Z calculated by the height displacement amount calculation unit 242. Since the height displacement Z could be calculated from the peak position offset D, the control unit 101 adjusted the height of the sample stage 110 based on the peak position of the two-dimensional peak detection data.

[0077] However, the present invention is not limited to the embodiments described above. In the embodiments described above, an example configuration was explained in which the present invention is applied to an X-ray analyzer for analyzing the composition and thickness of a thin film by rocking curve measurement, using a thin film substrate as a sample S. However, it goes without saying that the applications of the present invention are not limited to this. For example, the present invention can be applied to X-ray analysis of samples other than thin-film substrate samples S. Furthermore, the invention of claim 1, which performs data processing using positional information of the peak position identified in the two-dimensional peak detection data, the invention of claim 6, which relates to the evaluation of the warpage of sample S, and the invention of claim 8, which relates to the height adjustment of sample S, can all be applied to X-ray analyzers that perform measurements other than rocking curve measurement.

Claims

1. An X-ray diffraction data processing device for processing two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ by scanning the incident angle θ of the incident X-rays and the angular direction 2θ in which the two-dimensional X-ray detector is positioned, using an X-ray analyzer that irradiates a measurement point set on the surface of a sample with incident X-rays from the direction of incident angle θ, and positions a two-dimensional X-ray detector at an angular direction of 2θ with respect to the direction of incident angle θ, wherein the incident angle θ of the incident X-rays and the angular direction 2θ in which the two-dimensional X-ray detector is positioned are scanned, and the two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ, wherein A peak two-dimensional detection data extraction unit extracts the two-dimensional detection data (peak two-dimensional detection data) of the diffracted X-rays with the maximum total X-ray intensity from the two-dimensional detection data of diffracted X-rays obtained at the aforementioned multiple scanning angles 2θ / θ, A peak position identification unit identifies the position (peak position) where the X-ray intensity is maximum from the aforementioned two-dimensional peak detection data, A data processing unit that performs data processing using the positional information of the peak position identified in the aforementioned two-dimensional peak detection data, An X-ray diffraction data processing device characterized by comprising the following features.

2. The aforementioned data processing unit A target area setting unit sets a target area surrounding the aforementioned peak position, A profile generation unit that, for each two-dimensional detection data of diffracted X-rays obtained at the plurality of scanning angles 2θ / θ, integrates the X-ray intensity within the region corresponding to the target region, and creates a rocking curve profile based on the X-ray intensity integrated for each of these two-dimensional detection data, The X-ray diffraction data processing apparatus according to claim 1, characterized by including the following:

3. The two-dimensional X-ray detector has a detection surface for detecting diffracted X-rays, and a reference detection point is set in advance on the detection surface. When incident X-rays are irradiated onto the surface of a symmetrically reflecting sample from the direction of an incident angle θ, the detector is positioned so that the optical axis of the diffracted X-rays appearing from the surface of the sample in the direction of a diffraction angle 2θ is incident on the reference detection point. The X-ray diffraction data processing apparatus according to claim 1, characterized in that the peak position identification unit is configured to determine the offset amount between the peak position recorded in the two-dimensional peak detection data and the reference detection point.

4. The X-ray diffraction data processing apparatus according to claim 3, characterized in that the peak position identification unit is configured to determine the following Δω and Δχ as offset amounts between the peak position and the reference detection point. Δω: Offset amount along the trajectory ω of the reference detection point during 2θ / θ scanning. Δχ: Offset amount along the circular arc trajectory χ centered on the reference detection point at a scanning angle of 2θ / θ = 0°.

5. The X-ray diffraction data processing apparatus according to claim 2, characterized in that the target area setting unit has a function to arbitrarily adjust the width of the target area surrounding the peak position that corresponds to the angular direction of 2θ.

6. The aforementioned data processing unit A peak shift amount calculation unit calculates the shift amount of the scanning angle 2θ / θ by comparing the scanning angle 2θ / θ of the two-dimensional peak detection data obtained for multiple measurement points on a straight line set on the surface of the flat plate-shaped sample with the scanning angle 2θ / θ of the sample, A radius of curvature calculation unit calculates the radius of curvature of the crystal lattice plane of the sample based on the shift amount of the scanning angle 2θ / θ obtained by the peak shift amount calculation unit, The X-ray diffraction data processing apparatus according to claim 1, characterized by including the following:

7. In an X-ray analyzer, incident X-rays are irradiated onto a measurement point set on the surface of a sample from a direction of incident angle θ, and a two-dimensional X-ray detector is positioned at an angle of 2θ with respect to the direction of the incident angle θ, and the diffracted X-rays diffracted by the sample are detected by the two-dimensional X-ray detector. An X-ray analyzer characterized by comprising an X-ray diffraction data processing device as described in any one of claims 1 to 6.

8. A height-adjustable sample stand for placing the aforementioned sample, The system comprises a sample stage control unit having at least the function of controlling the height of the sample stage, The X-ray analyzer according to claim 7, characterized in that the sample stage control unit is configured to adjust the height of the sample stage based on the peak position of the two-dimensional peak detection data.

9. In an X-ray analyzer in which incident X-rays are irradiated onto a measurement point set on the surface of a sample from a direction of incident angle θ, and a two-dimensional X-ray detector is positioned at an angle of 2θ with respect to the direction of the incident angle θ, and the diffracted X-rays diffracted by the sample are detected by the two-dimensional X-ray detector, An X-ray diffraction data processing method is performed by an X-ray diffraction data processing device for scanning the incident angle θ of the incident X-rays and the angular direction 2θ in which the two-dimensional X-ray detector is positioned, and processing two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ, wherein A peak two-dimensional detection data extraction step is performed to extract the two-dimensional detection data of the diffracted X-ray with the maximum total X-ray intensity (peak two-dimensional detection data) from the two-dimensional detection data of diffracted X-rays obtained at the aforementioned multiple scanning angles 2θ / θ, A peak position identification step involves identifying the position (peak position) where the X-ray intensity is maximum from the aforementioned two-dimensional peak detection data, A data processing step that performs data processing using the positional information of the peak position identified in the aforementioned two-dimensional peak detection data, A method for processing X-ray diffraction data, characterized by including the following:

10. In an X-ray analyzer in which incident X-rays are irradiated onto a measurement point set on the surface of a sample from a direction of incident angle θ, and a two-dimensional X-ray detector is positioned at an angle of 2θ with respect to the direction of the incident angle θ, and the diffracted X-rays diffracted by the sample are detected by the two-dimensional X-ray detector, An X-ray diffraction data processing program executed by an X-ray diffraction data processing device for scanning the incident angle θ of the incident X-rays and the angular direction 2θ in which the two-dimensional X-ray detector is positioned, and processing two-dimensional detection data of diffracted X-rays obtained at multiple scanning angles 2θ / θ, wherein A peak two-dimensional detection data extraction step is performed to extract the two-dimensional detection data of the diffracted X-ray with the maximum total X-ray intensity (peak two-dimensional detection data) from the two-dimensional detection data of diffracted X-rays obtained at the aforementioned multiple scanning angles 2θ / θ, A peak position identification step involves identifying the position (peak position) where the X-ray intensity is maximum from the aforementioned two-dimensional peak detection data, A data processing step that performs data processing using the positional information of the peak position identified in the aforementioned two-dimensional peak detection data, An X-ray diffraction data processing program characterized by including the following:

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