X-ray diffraction measurement method and X-ray diffraction measurement device

Abstract

To enable stable X-ray diffraction measurement of fine crystal grains.SOLUTION: An X-ray diffraction measurement method has: a search step of searching for a fine crystal grain having a crystal plane (SC) extending along a substrate surface from among multiple fine crystal grains (CP) disposed on the substrate surface (SF) of a substrate (SB0); and a measurement step of making X-ray diffraction measurement of the searched fine crystal grain.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an X-ray diffraction measurement method and an X-ray diffraction measurement device. [Background technology]

[0002] X-ray diffraction is generally known as a conventional technique. For example, Patent Document 1 discloses a technique for preventing deterioration in measurement accuracy of characteristic values ​​even when the crystal grains of the measurement object are large (see abstract). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-71401 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, with recent technological advances, for example, X-ray diffraction analysis and X-ray diffraction imaging of crystal grains with particle sizes on the order of μm or less (hereinafter referred to as "microcrystal grains") have become common.

[0005] However, analyzing small crystal grains using X-ray diffraction is not easy. Generally, X-ray diffraction requires that X-rays be incident at an appropriate angle relative to the crystal orientation of the crystal grains. However, due to the small size of small crystal grains, it is not easy to confirm the crystal orientation or set the angle. Furthermore, small crystal grains tend to move and rotate easily, making stable measurements difficult. For this reason, it is possible to fix the crystal grains using, for example, a fixative, but this can reduce the accuracy of the measurement and the quality of the sample (small crystal grains).

[0006] An object of one aspect of the present invention is to realize stable X-ray diffraction measurement of small crystal grains. [Means for solving the problem]

[0007] In order to solve the above problem, an X-ray diffraction measurement method according to one embodiment of the present invention includes a search step of searching for a micro-crystal grain having a crystal plane along the substrate surface from among a plurality of micro-crystal grains arranged on the substrate surface of a substrate, and a measurement step of performing X-ray diffraction measurement of the searched micro-crystal grain. [Effects of the Invention]

[0008] According to one aspect of the present invention, stable X-ray diffraction measurement of microcrystalline grains can be achieved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of an X-ray diffraction apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a diagram illustrating an example of a sample holding chip. [Figure 3] FIG. 1 is a diagram illustrating an example of minute crystal grains arranged on a flat substrate surface of a substrate. [Figure 4] FIG. 2 is a flow chart showing an example of an operation procedure of the X-ray diffraction apparatus. [Figure 5] FIG. 2 is an enlarged view of the vicinity of a search area on the substrate surface. [Figure 6] FIG. 1 is a diagram illustrating an example of minute crystal grains arranged on a substrate surface. [Figure 7] FIG. 2 is a diagram illustrating an example of an X-ray spot that appears on the detection surface of an X-ray detector. [Figure 8] FIG. 1 is a diagram illustrating an example of a rocking curve. [Figure 9] FIG. 2 is a diagram illustrating an example of an X-ray spot that appears on the detection surface of an X-ray detector. [Figure 10] FIG. 4 is a diagram illustrating an example of an X-ray diffraction apparatus according to a second embodiment of the present invention. [Figure 11] FIG. 2 is a partial cross-sectional view showing a cross-sectional state of an example of a holder of an X-ray diffraction device. [Figure 12] FIG. 2 is an enlarged view of the vicinity of a search area on the substrate surface. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Embodiment 1) Hereinafter, a first embodiment of the present invention will be described in detail. Fig. 1 is a diagram showing an example of an X-ray diffraction apparatus according to the first embodiment of the present invention. Here, an xyz coordinate system is set with the vertical direction as the z axis.

[0011] (X-ray diffractometer 10) The X-ray diffraction apparatus 10 has a holder 11, an X-ray emitter 12, an X-ray detector 13, translational scanning units 14, 15, 16, a rotational scanning unit 17, and a control unit 20, and measures the microcrystalline grains CP on the sample holding chip SB held by the holder 11 by X-ray diffraction.

[0012] The fine crystal grains CP are crystal grains with a grain size of the order of μm or less, for example, 100 nm or less (for example, 40 nm to 100 nm). Here, as an example of the fine crystal grains CP, a 40 nm crystal grain of barium titanate (BaTiO3) will be described.

[0013] However, the grain size and constituent material of the microcrystalline grains CP can be changed as appropriate. When the grain size or crystallinity of the microcrystalline grains CP is changed, the beam diameter, translation position (x, z), and range and step of change of the angle (Φ) of the X-ray beam Xi, which will be described later, may be changed accordingly. In particular, it is preferable to change the range of change of the angle (Φ) according to the crystallinity, and it is preferable to change the step of the angle (Φ) according to the grain size.

[0014] The holder 11 has a generally flat plate shape and holds a sample holder chip SB (substrate SB0) on which a plurality of microcrystalline grains CP are arranged. Here, the x-axis and z-axis are set on the sample holder chip SB, particularly along its main surface (substrate surface SF, described later). The holder 11 may also have a through-hole AP, as will be shown in FIGS. 10 and 11.

[0015] Here, the main surface of the holder 11, and ultimately the substrate surface SF of the sample holder chip SB, is aligned with the X-axis. The X-ray emitter 12 and X-ray detector 13 are disposed on the front side (positive Y-axis side) of the substrate surface SF. That is, the X-ray detector 13 detects diffracted X-rays that are diffracted by the microcrystalline grains CP and do not pass through the sample holder chip SB. This measurement mode is called reflection measurement. On the other hand, by changing the position of the X-ray detector 13, the X-ray detector 13 can detect diffracted X-rays that are diffracted by the microcrystalline grains CP and pass through the sample holder chip SB. This measurement mode is called transmission measurement. This will be described in detail in the second embodiment.

[0016] The holder 11 (sample holding chip SB) is translated in the x, y, and z directions by translational scanning units 14, 15, 16 and rotational scanning unit 17, and rotated on the sample holding chip SB around a rotation axis C set approximately coaxial with the z axis.

[0017] 1, the sample holder chip SB is so-called vertically oriented and has a main surface (substrate surface SF) along the vertical direction. The substrate surface SF can be inclined with respect to the horizontal plane or can be aligned along a vertical line (for example, approximately parallel). However, the sample holder chip SB may also be so-called horizontally oriented and have a main surface (substrate surface SF) along the horizontal plane.

[0018] Figure 2 shows an example of a sample holder chip SB. Figure 2(A) is a plan view of the sample holder chip SB, and Figure 2(B) is an enlarged plan view of the vicinity of the center of the sample holder chip SB. The sample holder chip SB has a substrate SB0 near the center on which microcrystalline grains CP are arranged.

[0019] The substrate SB0 can be made of a thin film, for example, several micrometers thick, made of a material (for example, silicon nitride) that does not easily disturb the wavefront of X-rays. However, the thickness of the substrate SB0 may be thinner, for example, on the order of 100 nm. The substrate SB0 has a flat substrate surface (main surface) SF on which the microcrystalline grains CP are placed. The microcrystalline grains CP are arranged on this substrate surface SF.

[0020] The heater HT is an electric heating wire for adjusting the temperature of the microcrystalline grains CP, and is disposed on the lower layer (back side) of the substrate SB0. The microcrystalline grains CP can be heated by passing a current through the heater HT. Here, the heater HT has a spiral shape, but it may have other shapes. The temperature near the sample holder chip SB can be measured by the resistance value of the heater HT or by a thermocouple.

[0021] Here, instead of the heater HT, or together with the heater HT, a cooler for cooling the microcrystalline grains CP may be arranged in the sample holder chip SB.

[0022] A virtual search area MA for searching for microcrystalline grains CP is set on the substrate surface SF. The search area MA is, for example, within a size of 200 μm × 200 μm and is set near the center of the substrate SB0 (sample holder chip SB). This search area MA is irradiated and scanned with an X-ray beam Xi from the X-ray emitter 12.

[0023] The explanation will be continued by returning to Figure 1. Although not shown for the sake of clarity, the holder 11 is placed in a vacuum chamber, which enables X-ray diffraction measurement of the microcrystalline grains CP in a vacuum or in various gas environments.

[0024] The X-ray emitter 12 emits an X-ray beam Xi to the microcrystalline grains CP on the sample holding chip SB (substrate SB0). This X-ray beam Xi has a small beam diameter (full width at half maximum) of, for example, several μm or less (e.g., 2 μm) on the substrate surface SF. The small diameter of the X-ray beam Xi facilitates the search, measurement, and selection of the microcrystalline grains CP. Specifically, the X-ray beam Xi is focused, and the X-ray density is increased, making it easier to search and measure the microcrystalline grains CP. Furthermore, the small beam diameter of the X-ray beam Xi reduces the number of microcrystalline grains CP that enter the irradiation area of ​​the X-ray beam Xi, making it easier to select a single particle. The X-ray emitter 12 may (1) have a thermionic, field emission, or Schottky electron gun, or (2) may be an insertion light source (e.g., SPring-8) installed in various accelerators including synchrotrons, storage rings, linacs, and microtrons. The insertion device may include a polarized electromagnetic light source.

[0025] When a synchrotron radiation source such as SPring-8 or a free electron laser such as SACLA is used, coherent X-rays are emitted from the X-ray emitter 12. In this case, the Bragg coherent X-ray diffraction imaging (BCDI) method is applied to acquire a diffraction pattern and perform phase retrieval calculations, making it possible to observe the three-dimensional structure of the microcrystalline grains CP, including both their external and internal shapes.

[0026] Here, the central axis of the X-ray beam Xi emitted from the X-ray emitter 12 is referred to as the emission axis A1. That is, the X-ray emitter 12 emits the X-ray beam Xi along the emission axis A1. The emission axis A1 forms an angle (first angle) θ1 with respect to the substrate surface SF.

[0027] The X-ray detector 13 is a detector that detects X-rays Xd diffracted by the microcrystalline grains CP, and has a detection surface on which a large number of detection elements for capturing a diffraction pattern are arranged two-dimensionally.

[0028] Here, the central axis of the X-rays Xd incident on the center of the detection surface of the X-ray detector 13 is referred to as the incident axis A2. That is, the X-ray detector 13 captures the incident X-rays Xd at the center of the detection surface along the incident axis A2. The incident axis A2 forms an angle θ2 with the substrate surface SF. Note that the incident axis A2 may have an error corresponding to the width of the detection area of ​​the X-ray detector 13 with respect to the center of the detection surface.

[0029] The translational scanning units 14, 15, 16 and the rotational scanning unit 17 collectively function as a translational / rotation mechanism that translates and rotates the holder 11 relative to the X-ray emitter 12 (ultimately, the X-ray beam Xi).

[0030] The translational scanning units 14, 15, and 16 are translational tables that translate the holder 11 (sample holding chip SB) in the x-axis direction, y-axis direction, and z-axis direction, respectively. This translation is performed with a high resolution of, for example, 100 nm.

[0031] The rotary scanning unit 17 is a rotary table, such as a goniometer, that rotates the holder 11 (sample holding chip SB) on the sample holding chip SB around a rotation axis C that is set approximately parallel to the Z axis. This rotation is performed with a high resolution of, for example, 1 / 1000°.

[0032] The control unit 20 has a processor 21 and a memory 22. The memory 22 stores a program P1. The processor 21 operates according to the program P1 and executes an X-ray diffraction measurement method, which will be described later.

[0033] (Stable arrangement of small crystal grains CP) The X-ray diffraction apparatus 10 can search for microcrystalline grains CP that are stably arranged on the substrate surface SF. First, the microcrystalline grains CP that are stably arranged on the substrate surface SF will be described.

[0034] 3 is a diagram showing an example of microcrystalline grains CP arranged on the flat substrate surface SF of the substrate SB0. Here, the substrate surface SF is shown as viewed from the Z-axis (vertical) direction, and microcrystalline grains CP1 to CP4 are arranged on the substrate surface SF. The microcrystalline grains CP1 and CP3 have an approximately spherical shape overall and do not have a flat surface FF, so they are not stably arranged with respect to the substrate surface SF.

[0035] In contrast, the fine crystal grains CP2 and CP4 have flat surfaces FF. Of these, the flat surface FF of the fine crystal grain CP2 is tilted with respect to the substrate surface SF, and is therefore not stably disposed with respect to the substrate surface SF.

[0036] In contrast, the flat surface FF of the microcrystalline grain CP4 is in contact with the substrate surface SF and is approximately parallel to it. In this case, for example, van der Waals forces act between the microcrystalline grain CP4 (flat surface FF) and the substrate surface SF, and even if the substrate surface SF is tilted, the microcrystalline grain CP4 is stably positioned (fixed) to the substrate surface SF. Here, the flat surface FF is the exposed crystal surface (exposed crystal surface) SC0 of the microcrystalline grain CP4. The exposed crystal surface SC0 has high flatness and is easily adhered to and fixed to the substrate surface SF. In general, powder of microcrystalline grains CP4 (microcrystalline grains in the broad sense) is thought to contain a certain proportion of microcrystalline grains CP0 having exposed crystal surfaces SC0.

[0037] In other words, when the microcrystalline grains CP are scattered on the substrate surface SF, it is expected that the exposed crystal surface SC0 of any of the microcrystalline grains CP having an exposed crystal surface SC0 will be adhered and fixed along the substrate surface SF at the time of scattering.

[0038] The X-ray diffraction apparatus 10 makes it possible to search for "microcrystalline grains CP0 having exposed crystal faces SC0 in close contact with the substrate surface SF." On this premise, the X-ray diffraction apparatus 10 searches for "microcrystalline grains CP having crystal faces SC along the substrate surface SF." If the searched microcrystalline grain CP is stable with respect to the substrate surface SF, there is a high possibility that this microcrystalline grain CP is "microcrystalline grain CP0 having exposed crystal faces SC0 in close contact with the substrate surface SF."

[0039] Generally, it is possible to find microcrystalline grains CP fixed to the substrate surface SF by checking the stability of the diffraction pattern on the X-ray detector 13 while changing the position and angle of the X-ray beam Xi relative to the substrate surface SF. However, such a search takes time because there are many parameters to be changed. As will be described later, this embodiment enables efficient search and measurement by limiting the range of parameters to be changed (especially the angle).

[0040] (X-ray diffraction measurement method) 4 is a flow diagram showing an example of the operating procedure of the X-ray diffraction apparatus 10. The X-ray diffraction measurement process is roughly divided into a preparation process (step S1), a search process (step S2), a position adjustment process (step S3), and a measurement process (step S4). Steps S1, S2, and S3 are further divided into steps S11 to S13, steps S21 to S24, and steps S31 to S33, respectively.

[0041] A. Preparation (Step S1) (1) Setting the substrate SB0 (crystal grains) (Step S11) Microcrystalline particles CP are scattered on the substrate surface SF. For example, a powder of microcrystalline particles CP is dispersed in a volatile liquid (e.g., ethanol) to produce a dispersion in which the microcrystalline particles CP are dispersed in the liquid. This dispersion is then dropped onto the substrate surface SF of the sample holder chip SB, and the liquid is evaporated. As a result, a sample holder chip SB is produced in which a plurality of microcrystalline particles CP are dispersed and arranged on the substrate surface SF. The sample holder chip SB produced in this manner is fixed to the holder 11.

[0042] As described above, it is considered that the plurality of micro crystal grains CP include a certain proportion of micro crystal grains CP0 having exposed crystal faces SC0 in close contact with the substrate surface SF. In the subsequent search step (step S2), micro crystal grains CP0 having exposed crystal faces SC0 in close contact with the substrate surface SF are searched for.

[0043] 5 is an enlarged view of the vicinity of the search area MA on the substrate surface SF. The settings of the X-ray diffraction apparatus 10 will be described below with reference to this figure.

[0044] (2) Setting of X-ray diffractometer 10 (step S12) 5 is an enlarged view of the vicinity of the search area MA on the substrate surface SF. Here, the X-ray diffraction apparatus 10 is set so as to satisfy the following conditions (a) to (c).

[0045] (a) The emission axis A1 and the incident axis A2 intersect on the substrate surface SF (at point O), and the plane S0 defined by the emission axis A1 and the incident axis A2 is perpendicular to the substrate surface SF. (b) The angle (second angle) θ0 (=θ1+θ2) between the exit axis A1 and the entrance axis A2 is set to twice the Bragg angle θbg. θ0=θ1+θ2=2·θbg ……Formula (1) θbg=sin -1 (2·d / (n·λ)) ……Formula (2) d: spacing between crystal planes (lattice planes) n: reflection degree (integer)

[0046] Conditions (a) and (b) correspond to the requirement that the microcrystalline grain CP0 on the substrate surface SF has a crystal plane SC parallel to the substrate surface SF. Condition (a) is based on the fact that the incident X-rays on the crystal plane SC and the diffracted X-rays are positioned on a plane S0 perpendicular to the crystal plane SC (ultimately, the substrate surface SF). Condition (b) is the condition that angles θ1 and θ2 must satisfy in X-ray diffraction.

[0047] Here, the crystal plane (lattice plane) that serves as the basis for the spacing d is preferably the crystal plane SC, which is likely to appear as the exposed crystal plane SC0 in the microcrystalline grains CP. In the case of the barium titanate in this example, the (100) crystal plane may be selected as the crystal plane SC. In this case, the spacing d is approximately 0.399 nm, and if the wavelength λ of the X-ray is, for example, 0.155 nm, the Bragg angle θbg when the order of reflection n = 2 is approximately 22.86°.

[0048] Here, the (200) Bragg reflection, which has a strong diffraction intensity, is selected and used for measurement, so the order of reflection n is set to "2." This also applies hereinafter. Note that the order of reflection n may be a number other than 2.

[0049] (c) The rotation axis C (Z axis) is set to be along the substrate surface SF and pass through the point O where the X-ray beam Xi is irradiated. This makes it possible to obtain an accurate rocking curve of the microcrystalline grain CP by rotating the substrate SB0 around the rotation axis C. Here, the rotation axis C is set to be perpendicular to the plane S0 defined by the exit axis A1 and the entrance axis A2. However, the rotation axis C may be tilted with respect to the plane S0. Even if the rotation axis C is tilted with respect to the plane S0, the microcrystalline grain CP can be searched for.

[0050] (3) Setting the measurement environment (temperature, gas type, gas pressure) (step S13) The temperature and atmosphere (vacuum or gas atmosphere: gas type, gas pressure) surrounding the fine crystal grains CP are set appropriately. This setting is mainly for specifying the measurement conditions for the fine crystal grains CP. The crystalline state of the fine crystal grains CP can change due to temperature, etc.

[0051] B. Search for crystal grains (Step S2) As described above, a plurality of micro crystal grains CP are arranged within the search area MA. In the search step, a micro crystal grain CP having a crystal face SC along the substrate surface SF is searched for from the plurality of micro crystal grains CP arranged on the substrate surface SF of the substrate SB0.

[0052] 6 is a diagram showing an example of fine crystal grains CP arranged on the substrate surface SF, in which fine crystal grains CPa, CPb, and CPc are arranged on the substrate surface SF.

[0053] (1) Translation (x, z) of the substrate SB0 (step S21) The translation step (step S21) is a step of translating the X-ray focusing area relative to the substrate SB0. Here, the substrate SB0 is translated along the substrate surface SF (planar scanning) to move the focusing position (focusing area) of the X-ray beam Xi. For example, starting from near the center of the search area MA, the substrate SB0 is scanned in the x and z directions in 2 μm steps.

[0054] (2) Rotation (φ) of the substrate SB0 and detection of diffracted X-rays (Step S22) After translating the substrate SB0, it is temporarily stopped and a rotation and detection step (step S22) is performed. That is, the diffracted X-rays are detected while the substrate SB0 is slightly rotated around the rotation axis C. The rotation and detection step (step S22) is a detection step in which the incident angle (first angle described below) of the X-rays (X-ray beam Xi) on the substrate surface SF is changed to detect the intensity of the diffracted X-rays diffracted by the microcrystalline grains CP. The X-rays are emitted from the X-ray emitter 12 along the emission axis A1 of the X-ray emitter 12 onto the substrate surface SF, and the diffracted X-rays are incident on the X-ray detector along the incident axis of the X-ray detector and detected. Here, the incident angle of the X-rays is determined by the angle θ1 (first angle) that the emission axis A1 makes with respect to the substrate surface SF.

[0055] At this time, the angle θ1 (first angle) is changed within a range of, for example, ±5° of the Bragg angle θbg. As an example, the angle θ1 is scanned within a range of approximately ±2° around the Bragg angle θbg, for example, at a rate of approximately 0.1° / sec, and the change in the intensity of the detected X-rays is measured. As will be described later, by slightly changing the angles θ1 and θ2 around the Bragg angle θbg, it is possible to easily find minute crystal grains CP having crystal planes SC aligned with the substrate surface SF.

[0056] In the rotation and detection step (step S22), conditions (a) to (c) are maintained. As described above, the emission axis A1 and the incidence axis A2 intersect with each other and are straight lines that define a predetermined plane S0. Here, the substrate surface SF is maintained in a state of being upright with respect to the predetermined plane S0 (for example, the substrate surface SF is perpendicular to the plane S0) (condition (a)). The angle θ0 (second angle) formed by the emission axis A1 of the X-ray emitter 12 and the incidence axis A2 of the diffracted X-rays on the X-ray detector 13 is maintained at approximately twice the Bragg angle θbg (for example, preferably 1.95 times or more and 2.05 times or less, and more preferably 1.98 times or more and 2.02 times or less) (condition (b)). The rotation axis C (Z axis) is maintained in a state of being along the substrate surface SF and passing through the point O irradiated with the X-ray beam Xi (condition (c)).

[0057] (3) Determining whether diffracted X-rays are detected (step S23) The determination step (step S23) is a step of determining whether or not the microcrystalline grain CP has a crystal plane SC along the substrate surface SF based on the correspondence between the incident angle of the X-ray (angle θ1: first angle) and the intensity of the detected diffracted X-ray. If the intensity of the diffracted X-ray increases at a specific angle during rotation, this means that a microcrystalline grain CP having a crystal plane SC along the substrate surface SF (more preferably, a microcrystalline grain CP0 having an exposed crystal plane SC0 in close contact with the substrate surface SF) has been found ("YES" in step S23).

[0058] The rotation and detection process (step S22) and the determination process (step S23) function as a surface determination process for determining whether at least one of one or more microcrystal grains in the translated focusing area has a crystal surface along the substrate surface.

[0059] FIG. 7 is a diagram showing an example of an X-ray spot appearing on the detection surface of the X-ray detector 13. For ease of understanding, it is assumed that spots Xa, Xb, and Xc corresponding to the microcrystalline grains CPa, CPb, and CPc shown in FIG. 6 appear simultaneously. By slightly rotating the substrate SB0, the brightness of these spots Xa, Xb, and Xc changes significantly (in other words, they blink, turning on and off). In this way, by slightly changing the angles θ1 and θ2 in conjunction with the Bragg angle θbg, it is possible to easily find the microcrystalline grain CP having the crystal plane SC along the substrate surface SF.

[0060] In the determination step (step S23), if a diffracted X-ray (spot) with high brightness compared to the background is detected at angle θ1 near the Bragg angle θbg ("YES" in step S23), the process proceeds to the next step S24.

[0061] If the determination in step S23 is "NO," the substrate SB0 is translated (x, z) (step S21), rotated (φ), detected (step S22), and determined (step S23) repeatedly. For example, translation is repeated within a range of ±50 μm. Generally, minute crystal grains CP having crystal planes SC aligned with the substrate surface SF are often found within a range narrower than ±50 μm.

[0062] (4) Determining the stability of the diffracted X-ray intensity (step S24) If high-intensity diffracted X-rays are detected ("YES" in step S23), the process proceeds to the stability determination process (stability determination process, step S24), where it is determined whether the microcrystal grains CP determined in the surface determination process (steps S22, S23) to have crystal planes SC along the substrate surface SF are stable with respect to the substrate surface SF. Specifically, it is determined whether the intensity of the diffracted X-rays is stable. For example, if the diffracted X-rays remain in a high-intensity state (bright state) for a period of about 30 seconds to 1 minute, the microcrystal grains CP are determined to be stable with respect to the substrate surface SF. In this case, the microcrystal grains CP determined to be stable with respect to the substrate surface are likely to be microcrystal grains CP0 having crystal planes SC0 that are in close contact (exposed) with the substrate surface SF. If the determination in the stability determination process (step S24) is "YES," the process proceeds to the position adjustment process (step S3).

[0063] If the intensity of the diffracted X-rays is not stable ("NO" in step S24), return to step S21 and start the search again. Generally, the diffracted X-ray spots (microcrystal grains CP) include both stable and unstable ones. A stable microcrystal grain CP is considered to be a microcrystal grain CP0 having an exposed crystal plane SC0 that is in close contact with the substrate surface SF. An unstable microcrystal grain CP is considered to be, for example, a microcrystal grain CP whose crystal plane SC temporarily became parallel to the substrate surface SF, but then the microcrystal grain CP rotated, etc., and this parallel relationship was lost. In such a case, the diffracted X-ray spot changes from a bright state to a dark state in an instant.

[0064] C. Adjustment of the position and angle of the crystal grains (Step S3) (1) Maximizing the intensity of diffracted X-rays (Step S31) In the search process, the focus is on finding a micro-crystal grain CP0 with an exposed crystal surface SC0 that is in close contact with the substrate surface SF, and the position (x, z) and angle (Φ) of the searched micro-crystal grain CP0 are set relatively roughly. In the position and angle adjustment process (step S3), the crystal grain is aligned more precisely.

[0065] Specifically, the substrate SB0 is rotated and then translated to maximize the intensity of the diffracted X-rays (step S31). The substrate SB0 is rotated to maximize the intensity, and then, with the rotation stopped, the substrate SB0 is translated in the xz directions to maximize the intensity of the diffracted X-rays. For example, the substrate is translated within a range of ±5 μm with an accuracy of 100 nm. As a result, the microcrystalline grain CP can be positioned at the center of the X-ray beam Xi. Note that step S31 may be repeated multiple times as necessary.

[0066] (2) Deriving the rocking curve (step S32) Once the intensity of the diffracted X-rays has been maximized, the rocking curve (the relationship between the angle φ and the intensity I of the diffracted X-rays) is determined. The angle φ is adjusted, for example, in 0.1° steps within a range of ±1°. The detection counts in the X-ray detector 13 are integrated for each scan point, for example, for about 5 to 10 seconds. In other words, the integrated amount of detection counts is increased to a level that allows comparison of the rocking curves.

[0067] (3) Determining the stability of the rocking curve (step S33) The rocking curve is repeatedly derived, and the stability of the rocking curve is judged based on the profile of the rocking curve and whether or not there is a change in the peak position. As a result, it becomes more certain that the detected microcrystalline grain CP is the microcrystalline grain CP0 having the exposed crystal surface SC0 in close contact with the substrate surface SF.

[0068] Figure 8 shows an example of a rocking curve. Two measured rocking curves, G1 and G2, are shown superimposed. The rocking curves are considered stable. That is, the profiles of rocking curves G1 and G2 match within the error range, and the peak deviation is within an angular scan step of 0.05°.

[0069] D. Measurement (Step S4) The measuring step is a step of performing X-ray diffraction measurement on the micro crystal grains CP found in the searching step, and is performed after the position adjusting step of the micro crystal grains CP.

[0070] Before the measurement step, it is preferable to finely adjust the angle and position. For example, the substrate SBO is rotated, translated in the X direction, and translated in the Z direction in that order to maximize the intensity of the diffracted X-rays. At this time, for example, the substrate SBO is scanned under the same conditions as in step S31 to further optimize the position and angle of the microcrystalline grains CP relative to the X-ray beam Xi.

[0071] In the measurement process, for example, the angle φ is scanned in steps of 0.05° within a range of ±1°. The measurement time (accumulation time) per point is, for example, 180 seconds, and the measurement is performed for a total of 2 hours. As a result, X-ray diffraction measurement of a single microcrystalline grain CP can be performed with high accuracy.

[0072] As described above, in this embodiment, among the micro-crystal grains CP arranged on the substrate surface SF of the substrate SB0, micro-crystal grains CP having crystal planes SC along the substrate surface SF are searched for and subjected to X-ray diffraction measurement. As a result, the micro-crystal grains CP arranged on the substrate SB0 in a stable state can be subjected to X-ray diffraction measurement with high accuracy.

[0073] X-ray diffraction measurements of the microcrystalline grains CP essentially require the setting of the exit axis A1 of the X-ray emitter 12 and the incident axis A2 of the X-ray detector 13 so that the Bragg angle θbg is satisfied with respect to the crystal plane SC of the microcrystalline grains CP. However, because the crystal plane SC of the microcrystalline grains CP is difficult to observe, it is not easy to align the angles of the exit axis A1 and the incident axis A2 with the crystal plane SC of the microcrystalline grains CP. For example, while the X-ray emitter 12 and the X-ray detector 13 can be operated with the exit axis A1 and the incident axis A2 aligned with the microcrystalline grains CP, the angles of the exit axis A1 and the incident axis A2 can be changed to determine the angle at which diffracted X-rays are detected. However, this requires changing two angles for each of the exit axis A1 and the incident axis A2, for a total of four angular coordinates, and this requires a long time to align the angles. Generally, three angles (e.g., rotation angles relative to the X-, Y-, and Z-axes) are required to determine the orientation of an object in three dimensions. Here, rotation about the exit axis A1 and the entrance axis A2 themselves is not an issue, so the orientations of the exit axis A1 and the entrance axis A2 are each defined by two angles.

[0074] In contrast, in this embodiment, the angles of the emission axis A1 and the incidence axis A2 are adjusted based on the substrate surface SF, which is easy to observe, and as a result, it becomes possible to adjust the angles to the microcrystalline grains CP (crystal plane SC), which are difficult to observe. As a result, the time required for angle adjustment can be significantly reduced.

[0075] Here, searching for a microcrystalline grain CP having a crystal plane SC along the substrate surface SF also leads to an efficient search for a microcrystalline grain CP0 fixed to the substrate surface SF. In other words, the searched microcrystalline grain CP is likely to be a microcrystalline grain CP0 having an exposed crystal plane SC0 in close contact with the substrate surface SF. This microcrystalline grain CP0 tends to be fixed to the substrate surface SF by, for example, van der Waals forces between the substrate surface SF and the exposed crystal plane SC0, which are in planar contact.

[0076] As a result, the alignment of the exit axis A1 and the entrance axis A2 and the stable search for the micro-crystal grains CP, which took about a day with conventional methods, can now be completed in less than 1 / 20 of the time, for example, within about an hour.

[0077] [Advantages of this embodiment] In this embodiment, the following advantages can be enjoyed. (1) It can be applied to CP with small crystal grains of 100 nm or less (for example, cubic BaTiO3 grains with a diameter of 40 nm). This enables stable X-ray diffraction measurements of small crystal grains of this size, which are generally considered to be mobile.

[0078] (2) It can accommodate vertical placement (vertical placement of the substrate SB0), which is considered more difficult to fix than horizontal placement (horizontal placement of the substrate SB0). Placing the substrate SB0 vertically facilitates use in combination with other measurement techniques. For example, as shown in the second embodiment described below, transmission measurement using another technique can be performed while performing transmission measurement of diffracted X-rays (Xd). Examples of transmission measurement using other techniques include absorption contrast imaging, i.e., imaging the degree to which an X-ray beam (Xi) is absorbed by microcrystalline grains CP.

[0079] (3) The substrate SB0 does not need to have a fixative (e.g., alumina) for fixing the microcrystalline grains CP. In this embodiment, the fixative does not cause changes in the properties of the microcrystalline grains CP or cause noise in X-ray diffraction. In other words, a fixative that comes into contact with the microcrystalline grains CP may change the original properties of the microcrystalline grains CP. Furthermore, when the fixative is hardened by firing at high temperatures, the crystalline structure of the microcrystalline grains CP may change or the microcrystalline grains CP may chemically react with the fixative at high temperatures. Furthermore, X-ray scattering from the fixative may cause noise in the original X-ray diffraction.

[0080] (4) The stability of the fixation of the fine grained CP is high. If the stability of the microcrystalline grains CP was determined (step S24), they were stably fixed to the substrate surface SF even with the passage of time and temperature changes. For example, the fluctuation of the peak position of the X-ray diffraction rocking curve after one hour was within 0.05°, which was almost within the measurement error. As shown in Figure 8, even when the temperature of the microcrystalline grains CP was changed to 40°C, 92°C, and 200°C, no substantial change was observed in the rocking curve profile.

[0081] [Variations] A modified example of the present invention will now be described. In this modified example, the substrate SB0 is rotated around a tilt axis (for example, a tilt axis along the X-axis) that tilts the substrate surface S0 relative to the Z-axis (rotation axis C). FIG. 9 is a diagram showing an example of an X-ray spot formed on the detection surface of the X-ray detector 13. Here, the rotation of the substrate SB0 around the tilt axis moves the X-ray spot on the detection surface of the X-ray detector 13 in the Z-axis direction (up and down). This movement can be used to position the X-ray spot at a suitable position on the detection surface of the X-ray detector 13. As shown in FIG. 9, the X-ray detector 13 is composed of two detection modules, one above the other, and the detection surface of the X-ray detector 13 has a seam BD between the detection modules. It is preferable that the X-ray spot be positioned near the center CN of the X-ray detector module, rather than near the seam BD.

[0082] This rotation around the tilt axis is particularly significant when the diameter of the microcrystalline grains CP is relatively large, and as a result, the distance from the microcrystalline grains CP to the detection surface must be relatively large. In this case, it becomes easy to position the diffracted X-rays from the microcrystalline grains CP near the center CN of the X-ray detector module.

[0083] (Embodiment 2) Hereinafter, a second embodiment of the present invention will be described. Fig. 10 corresponds to Fig. 1 and is a diagram illustrating an example of an X-ray diffraction apparatus according to the second embodiment of the present invention. The X-ray diffraction apparatus 10 according to the second embodiment has the same configuration as the X-ray diffraction apparatus 10 according to the first embodiment, but the orientation and shape of the holder 11 are different.

[0084] Here, the main surface of the holder 11, and ultimately the substrate surface SF of the sample holder chip SB, is aligned along the Y axis. As a result, the X-ray emitter 12 and the X-ray detector 13 are disposed on the front side (positive Y-axis side) and back side (negative Y-axis side) of the substrate surface SF, respectively. That is, the X-ray detector 13 detects diffracted X-rays (Xd) that are diffracted by the microcrystalline grains CP and pass through the sample holder chip SB (transmission measurement).

[0085] FIG. 11 is a partial cross-sectional view showing the cross-sectional state of the holder 11. As shown in FIGS. 10 and 11, the holder 11 has a through-hole AP that allows diffracted X-rays (Xd) to pass through. More specifically, the through-hole AP is formed in the holder 11 so as not to block either the X-ray beam (Xi) that has passed through the microcrystalline grains CP or the diffracted X-rays (Xd) from the microcrystalline grains CP. That is, the through-hole AP is a tapered through-hole with an area sufficiently larger than the search area MA. For example, the through-hole AP has a hole diameter of 2 mm on the side that contacts the sample holder chip SB (i.e., the side with the smaller diameter) and a taper angle of 90 degrees.

[0086] FIG. 12 corresponds to FIG. 5 and shows an enlarged view of the vicinity of the search area MA on the substrate surface SF. Here, the definitions of angles θ1 and θ2 are different from those in FIG. 5 (Embodiment 1). In FIG. 5, the angles formed by the emission axis A1 and the incidence axis A2 with respect to the substrate surface SF are angles θ1 (first angle) and θ2 (second angle). In contrast, in FIG. 10, the angles formed by the emission axis A1 and the incidence axis A2 with respect to a plane SS perpendicular to the substrate surface SF are defined as angles θ1 and θ2. Note that the plane SS is a plane perpendicular to both the plane S0 formed by the emission axis A1 and the incidence axis A2 and the substrate surface SF.

[0087] Even in such transmission measurement, the operating procedure (X-ray diffraction measurement method) shown in Fig. 4 can be applied. That is, from among the multiple microcrystal grains CP arranged on the substrate surface SF of the substrate SB0, a microcrystal grain CP having a crystal plane SC along the substrate surface SF can be searched for (search step: step S2), and X-ray diffraction measurement of the microcrystal grain CP can be performed (measurement step: step S4).

[0088] In the case of reflection measurement (embodiment 1), diffracted X-rays from the crystal plane SC along the substrate surface SF are used to search for the microcrystal grains CP. In contrast, in the case of transmission measurement (embodiment 2), diffracted X-rays from a crystal plane other than the crystal plane SC along the substrate surface SF are used to search for the microcrystal grains CP. This is because, in the case of transmission measurement, it is difficult to ensure the intensity of the diffracted X-rays from the crystal plane SC along the substrate surface SF. In transmission measurement, high-intensity diffracted X-rays can be obtained from a crystal plane that is nearly perpendicular to the crystal plane SC along the substrate surface SF.

[0089] In cubic and orthorhombic crystals, high-intensity diffracted X-rays can be obtained from crystal planes perpendicular to the crystal plane SC along the substrate plane SF, but in rhombohedral, orthorhombic, and triclinic crystals, there is no strict orthogonal relationship between the crystal plane SC along the substrate plane SF and the crystal plane from which high-intensity diffracted X-rays can be obtained. For this reason, diffracted X-rays are generally detected from crystal planes that are nearly perpendicular to the crystal plane SC along the substrate plane SF (in other words, crystal planes that intersect with the crystal plane SC).

[0090] When the crystal plane SC along the substrate surface SF is the

[0001] plane, reflection measurement detects diffracted X-rays from the (001) crystal plane, whereas transmission measurement detects diffracted X-rays from, for example, the (100) crystal plane and the (010) crystal plane. As mentioned above, when the microcrystalline grains CP are barium titanate, reflection measurement selects, for example, the (100) crystal plane as the crystal plane SC. In this case, the spacing d is approximately 0.399 nm, and the Bragg angle θbg when the reflection order n = 2 is approximately 22.86° (when the X-ray wavelength λ is 0.155 nm). In contrast, transmission measurement can select the (100) crystal plane as the target crystal plane SC, but the planes contributing to diffraction are, for example, the (010) crystal plane and the (001) crystal plane. When measuring using the (010) crystal plane, the spacing d is approximately 0.399 nm, and the Bragg angle θbg is approximately 22.86° when the order of reflection n = 2. On the other hand, when measuring using the (001) crystal plane, the spacing d is approximately 0.404 nm, and the Bragg angle θbg is approximately 22.56° when the order of reflection n = 2. In both cases, the wavelength λ of the X-rays is 0.155 nm.

[0091] In transmission measurement, as in reflection measurement, the incident angle (θ1) of the X-rays onto the substrate surface SF is changed to detect the intensity of the diffracted X-rays diffracted by the microcrystalline grains CP (detection process), and based on the correspondence between the change in incident angle and the intensity of the diffracted X-rays, it is determined whether the microcrystalline grains CP have a crystal plane SC along the substrate surface SF (determination process). However, the incident angle of the X-rays is defined by the angle θ1 (first angle) that the exit axis A1 makes with respect to the plane SS perpendicular to the substrate surface SF. Furthermore, in the detection process, the angle θ0 (second angle) that the incident axis A2 makes with respect to the exit axis A1 is maintained at 1.98 to 2.02 times the Bragg angle based on the spacing of the crystal plane intersecting with the crystal plane CP along the substrate surface SF.

[0092] As described above, when the microcrystalline grains CP are barium titanate, the Bragg angle θbg differs between approximately 22.86° and approximately 22.56° depending on the crystal plane (010) or (001), but this angle difference remains within 0.3°, or about 1% of the Bragg angle θbg. In other words, even considering that there may be multiple crystal planes contributing to diffraction, the angle θ0 (second angle) can be maintained at approximately twice the Bragg angle based on the spacing between the crystal planes intersecting with the crystal plane CP along the substrate surface SF (for example, preferably 1.95 times or more and 2.05 times or less, and more preferably 1.98 times or more and 2.02 times or less, as described above).

[0093] In any case, in transmission measurement, the "crystal plane SC along the substrate surface SF" is indirectly detected using diffracted X-rays from other crystal planes, and X-ray diffraction measurement of the microcrystalline grains CP is performed. Except for this point, the second embodiment is not essentially different from the first embodiment, and therefore a detailed description will be omitted.

[0094] 〔summary〕 The X-ray diffraction measurement method according to the first aspect of the present invention includes a search step of searching for a micro-crystal grain (CP) having a crystal plane (SC) aligned with the substrate surface (SF) from among a plurality of micro-crystal grains (CP) arranged on the substrate surface (SF) of a substrate (SB0), and a measurement step of performing X-ray diffraction measurement on the searched micro-crystal grain. By searching for a micro-crystal grain CP having a crystal plane SC aligned with the substrate surface SF, it is possible to find a micro-crystal grain CP that is stable with respect to the substrate surface SF, enabling stable X-ray diffraction measurement.

[0095] The X-ray diffraction measurement method according to the second aspect of the present invention is the same as that of the first aspect, and further includes a stability determination step of determining whether the detected microcrystal grains are stable with respect to the substrate surface, thereby making it possible to find microcrystal grains that are more stable with respect to the substrate surface.

[0096] In the X-ray diffraction measurement method according to the third aspect of the present invention, the microcrystal grains determined to be stable with respect to the substrate surface in the second aspect have crystal faces that are in close contact with the substrate surface, thereby making it possible to find microcrystal grains that are more stable with respect to the substrate surface.

[0097] In the X-ray diffraction measurement method according to a fourth aspect of the present invention, in any one of the first to third aspects, the search step includes a translation step of translating an X-ray focusing region relative to the substrate, and a plane determination step of determining whether at least one of one or more microcrystal grains in the translated focusing region has a crystal plane along the substrate surface, thereby enabling the search for microcrystal grains CP within the translation range of the substrate surface SF.

[0098] In the X-ray diffraction measurement method according to aspect 5 of the present invention, in the above aspect 4, the plane determination step includes a detection step of detecting the intensity of diffracted X-rays diffracted by the microcrystal grains by changing the incident angle (θ1) of X-rays on the substrate surface, and a determination step of determining whether the microcrystal grains have crystal planes along the substrate surface based on the correspondence between the incident angle and the intensity of the diffracted X-rays. Microcrystal grains can be searched for based on the correspondence between the incident angle of X-rays and the intensity of the diffracted X-rays.

[0099] A sixth aspect of the present invention relates to an X-ray diffraction measurement method according to the fifth aspect, in which the X-rays are emitted from an X-ray emitter (12) along an emission axis (A1) of the X-ray emitter onto the substrate surface, the diffracted X-rays are incident on an X-ray detector (13) along an incident axis (A2) of the X-ray detector and detected, and the incident angle of the X-rays is determined by a first angle (θ1) made by the emission axis with respect to the substrate surface. This allows microcrystal grains to be searched for by changing the first angle.

[0100] In the X-ray diffraction measurement method according to Aspect 7 of the present invention, in the detection step, the second angle (θ0) between the incident axis and the exit axis is maintained at 1.98 to 2.02 times the Bragg angle based on the spacing of crystal planes along the substrate surface. This allows microcrystal grains to be searched for without changing the angle between the exit axis A1 and the incident axis A2. Here, the second angle (θ0) in this case is preferably approximately twice the Bragg angle, that is, for example, 1.95 to 2.05 times, and more preferably, 1.98 to 2.02 times, as described above.

[0101] An X-ray diffraction measurement method according to an eighth aspect of the present invention is the same as that of the fifth aspect, in which the X-rays are emitted from an X-ray emitter (12) along an emission axis (A1) of the X-ray emitter toward the substrate surface, the diffracted X-rays are incident on an X-ray detector (13) along an incident axis (A2) of the X-ray detector and detected, and the incident angle of the X-rays is defined by a first angle (θ1) made by the emission axis with respect to a plane perpendicular to the substrate surface. This allows microcrystal grains to be searched for by changing the first angle.

[0102] A ninth aspect of the present invention relates to an X-ray diffraction measurement method according to the eighth aspect, wherein in the detection step, the second angle (θ0) between the incident axis and the exit axis is maintained at 1.98 to 2.02 times the Bragg angle, which is based on the spacing between the crystal planes along the substrate surface and the crystal planes intersecting the exit axis. This allows microcrystal grains to be searched for without changing the angle between the exit axis A1 and the incident axis A2. Here, the second angle (θ0) in this case is preferably approximately twice the Bragg angle, i.e., for example, 1.95 to 2.05 times, and more preferably, 1.98 to 2.02 times, as described above.

[0103] In the X-ray diffraction measurement method according to aspect 10 of the present invention, in the above aspect 7 or 9, the first angle is changed within a range of ±5° of the Bragg angle in the detection step, thereby making it possible to search for microcrystal grains while limiting the angle of the incident axis to a range of ±5°.

[0104] An X-ray diffraction measurement method according to an eleventh aspect of the present invention is the same as that of the sixth or eighth aspect, wherein in the detection step, the exit axis and the incident axis intersect with each other and are straight lines defining a predetermined plane (S0), and the substrate surface is maintained in an upright state relative to the predetermined plane (SS). This makes it possible to more reliably search for microcrystal grains having crystal planes along the substrate surface.

[0105] The X-ray diffraction measurement method according to a twelfth aspect of the present invention is the method according to any one of the first to eleventh aspects, wherein the grain size of the microcrystal grains is 100 nm or less. Even if the grain size is 100 nm or less, the microcrystal grains can be searched for.

[0106] A thirteenth aspect of the present invention relates to an X-ray diffraction measurement method in any one of the first to eleventh aspects, wherein the substrate surface is inclined with respect to a horizontal plane or is substantially parallel to a vertical line. Even if the substrate surface is not horizontal, stable microcrystal grains can be detected with respect to the substrate surface.

[0107] In the X-ray diffraction measurement method according to Aspect 14 of the present invention, in any one of Aspects 1 to 13, the substrate does not have a fixing agent for fixing the microcrystal grains on the substrate surface. Even if the microcrystal grains are not fixed on the substrate surface by a fixing agent, it is possible to find microcrystal grains that are stable relative to the substrate surface.

[0108] An X-ray diffraction measurement apparatus according to a fifteenth aspect of the present invention includes a holder (11) for holding a substrate having a substrate surface on which a plurality of microcrystal grains are arranged, an X-ray emitter (12) for emitting X-rays toward the microcrystal grains, an X-ray detector (13) for detecting diffracted X-rays diffracted by the microcrystal grains, a translation / rotation mechanism (14-17) for translating and rotating the holder relative to the X-ray emitter, and one or more processors (21). The processor controls the X-ray emitter, the X-ray detector, and the translation / rotation mechanism to perform a search step of searching for microcrystal grains having a crystal plane aligned with the substrate surface from among the plurality of microcrystal grains arranged on the substrate surface, and a measurement step of performing X-ray diffraction measurement on the searched microcrystal grains. Searching for microcrystal grains having a crystal plane aligned with the substrate surface enables the discovery of microcrystal grains stable with respect to the substrate surface, enabling stable X-ray diffraction measurement.

[0109] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0110] 10 X-ray diffractometer 11 Holder 12 X-ray emitter 13 X-ray detector 14, 15, 16 Translational scanning unit 17 Rotating scanning unit 20 Control Unit 21 processors 22 Memory

Claims

1. a searching step of searching for a micro-crystal grain having a crystal plane along the substrate surface from among a plurality of micro-crystal grains arranged on the substrate surface; a measuring step of performing X-ray diffraction measurement on the detected microcrystalline grains; The X-ray diffraction measurement method according to claim 1,

2. The searching step includes: a stability determination step of determining whether the detected microcrystal grains are stable with respect to the substrate surface; having The X-ray diffraction measurement method according to claim 1 .

3. The microcrystal grains determined to be stable with respect to the substrate surface have crystal faces that are in close contact with the substrate surface. The X-ray diffraction measurement method according to claim 2.

4. The searching step includes: a translation step of translating a focal region of the X-rays with respect to the substrate; a surface determination step of determining whether or not at least one of the one or more microcrystal grains in the translated light-collecting region has a crystal plane along the substrate surface; having The X-ray diffraction measurement method according to claim 1 .

5. The surface determination step includes: a detecting step of detecting the intensity of diffracted X-rays diffracted by the microcrystalline grains by changing the angle of incidence of X-rays on the substrate surface; a determining step of determining whether the microcrystal grains have a crystal plane along the substrate surface based on the correspondence relationship between the incident angle and the intensity of the diffracted X-rays; The X-ray diffraction measurement method according to claim 4, comprising:

6. the X-rays are emitted from the X-ray emitter along an emission axis of the X-ray emitter to the substrate surface; the diffracted X-rays are incident on the X-ray detector along an incident axis of the X-ray detector and detected; 6. The X-ray diffraction measurement method according to claim 5, wherein the incident angle of the X-rays is defined by a first angle formed by the emission axis with respect to the substrate surface.

7. 7. The X-ray diffraction measurement method according to claim 6, wherein in the detection step, a second angle formed by the incident axis with respect to the exit axis is maintained at 1.98 times or more and 2.02 times or less of a Bragg angle based on the spacing of crystal planes along the substrate surface.

8. the X-rays are emitted from the X-ray emitter along an emission axis of the X-ray emitter to the substrate surface; the diffracted X-rays are incident on the X-ray detector along an incident axis of the X-ray detector and detected; 6. The X-ray diffraction measurement method according to claim 5, wherein the incident angle of the X-rays is defined by a first angle that the emission axis makes with respect to a plane perpendicular to the substrate surface.

9. 9. The X-ray diffraction measurement method according to claim 8, wherein in the detection step, a second angle formed by the incident axis with respect to the exit axis is maintained at 1.98 times or more and 2.02 times or less of a Bragg angle based on the spacing between a crystal plane along the substrate surface and a crystal plane intersecting the crystal plane.

10. In the detecting step, the first angle is changed within a range of ±5° of the Bragg angle. The X-ray diffraction measurement method according to claim 7 or 9.

11. In the detection step, the emission axis and the incidence axis intersect with each other and are straight lines defining a predetermined plane, and the substrate surface is maintained in an upright state relative to the predetermined plane. The X-ray diffraction measurement method according to claim 6 or 8.

12. The particle size of the microcrystalline grains is 100 nm or less. The X-ray diffraction measurement method according to any one of claims 1 to 9.

13. The substrate surface is inclined relative to a horizontal plane or along a vertical line. The X-ray diffraction measurement method according to any one of claims 1 to 9.

14. The substrate does not have a fixing agent that fixes the microcrystalline grains on the substrate surface. The X-ray diffraction measurement method according to any one of claims 1 to 9.

15. a holder for holding a substrate having a substrate surface on which a plurality of microcrystalline grains are disposed; an X-ray emitter that emits X-rays toward the microcrystalline grains; an X-ray detector that detects diffracted X-rays diffracted by the microcrystalline grains; a translation / rotation mechanism that translates and rotates the holder relative to the X-ray emitter; one or more processors; Equipped with The processor controls the X-ray emitter, the X-ray detector, and the translation and rotation mechanism to a searching step of searching for a micro-crystal grain having a crystal plane along the substrate surface from among a plurality of micro-crystal grains arranged on the substrate surface; a measuring step of performing X-ray diffraction measurement on the detected microcrystalline grains; To execute X-ray diffraction measurement device.

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