JP2011185643A - X-ray small angle scattering measuring instrument and measuring method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray small angle scattering measuring instrument for measuring the size of nanosize particles on a two-dimensional plane and also measuring the planar distribution of the nanosize particles on the two-dimensional plane. <P>SOLUTION: The X-ray small angle scattering measuring instrument includes: an X-ray source for radiating X rays; a monochromator for converting the X rays radiated from the X-ray source to monochromatized parallel light to emit the same; a slit for prescribing the emission region of X rays of the monochromator to irradiate a linear region with the emitted X rays; a conveying part for conveying a plane stage which can be loaded with a sample to a position where the sample is irradiated with X rays; and a two-dimensional type detector for detecting the X-ray scattering image scattered from the linear region of the sample irradiated with X rays and the conveying part feeds the plane stage in the direction crossing the linear region in the longitudinal direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an X-ray small angle scattering measuring apparatus and a method for measuring a sample using the apparatus.

  In recent years, light-emitting devices using nanoparticles, nanostructures, and the like have attracted attention. For example, attempts have been made to create a light-emitting device by using semiconductor nanoparticles as a phosphor and dispersing the semiconductor nanoparticles to form a planar body. II-VI group compound semiconductors such as CdSe and III-V group compound semiconductors such as InP have been studied as materials for this device (for example, see Non-Patent Documents 1 and 2), and these semiconductor nanoparticles are used as phosphors. In this case, it is known that the fluorescence wavelength of the phosphor becomes shorter as the size of the semiconductor nanoparticles becomes smaller (see, for example, Non-Patent Document 2). For this reason, in the case of a light emitting device formed by dispersing semiconductor nanoparticles, it is important to measure the distribution along with the measurement of the size of the nanoparticles as an evaluation of the light emission characteristics.

  As a method for measuring the size of the nanoparticles, an X-ray small angle scattering method using X-ray scattering generated according to the size and shape of the particles is known. For example, in order to obtain three-dimensional information such as the shape, distribution, and thickness of a sample such as a nanoparticle created on a substrate, the sample on the substrate is irradiated with X-rays at a minute angle, In a reflected X-ray small angle scattering measurement apparatus that measures scattered X-rays using a two-dimensional detector, an attenuation mechanism 7 for attenuating a part of the X-ray intensity measured on the detector 6 surface is provided. It is known to provide (for example, refer to Patent Document 1).

JP 2007-163260 A

Olga I.I. Micic, Calvin J. et al. Curtis, Kim M. et al. Jones, Julian R. Sprague, and Arthur J. et al. Nozik, Synthesis and Characterization of InP Quantum Dots, “The Journal of Physical Chemistry”, Vol. 98, no. 19, 1994, p. 4966-4969 C. B. Murray, D.M. J. et al. Norris, and M.M. G. Bawendi, Synthesis and Charactarization of Nearly Monodisperse CdE (E = S, Se, Te) Semiconductor Nanocrystallines, “Journal of the American 115. 8706-8715

  However, when measuring a planar body in which semiconductor nanoparticles are dispersed, the above reflected X-ray small angle scattering measuring apparatus uses a two-dimensional detector, but is an apparatus that measures scattered X-rays near incident X-rays. The measurement range may not be sufficient. For this reason, expansion of the measurement range is desired. An apparatus that measures the size of nano-sized particles dispersed in a two-dimensional plane (for example, a plane) and evaluates how the particles are distributed in the plane is desired.

  The present invention has been made in view of such circumstances, and provides an apparatus for measuring the size of nano-sized particles in a two-dimensional plane and measuring the planar distribution of the particles in the two-dimensional plane. To do.

  According to the present invention, an X-ray source that emits X-rays, a monochromator that emits X-rays emitted from the X-ray source as monochromatic parallel light, and the emitted X-rays are linear regions. A slit that defines the X-ray emission area of the monochromator, a transport unit that transports a flat stage on which the sample can be mounted to a position where the sample is irradiated with X-rays, and X-ray irradiation A two-dimensional detector that detects an X-ray scattered image formed by scattering from the linear region of the sample that has been received, and the plane of the plane in a direction that intersects the longitudinal direction of the linear region An X-ray small angle scattering measurement apparatus for conveying a stage is provided.

  According to the present invention, an X-ray source that emits X-rays, a monochromator that emits X-rays emitted from the X-ray source as monochromatic parallel light, and the emitted X-rays are linear regions. A slit that defines the X-ray emission area of the monochromator, a transport unit that transports a flat stage on which the sample can be mounted to a position where the sample is irradiated with X-rays, and X-ray irradiation A two-dimensional detector that detects an X-ray scattered image formed by scattering from the linear region of the sample that has been received, and the plane of the plane in a direction that intersects the longitudinal direction of the linear region Since the stage is transported, the X-ray scattering intensity distribution with respect to the scattering angle is obtained for each position of the sample in the linear region based on the X-ray intensity distribution in the X-ray scattering image detected by the two-dimensional detector. be able to. For this reason, the two-dimensional X-ray scattering intensity distribution in the sample can be obtained by moving the sample in the direction intersecting with the longitudinal direction of the linear region. Therefore, by measuring a sample in which nano-sized particles are dispersed, the size of the nano-sized particles at each position in the sample can be measured, and the two-dimensional distribution of the particles in the sample can be measured. .

It is a figure for demonstrating the optical system of the X-ray small angle scattering measuring apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the optical system of the X-ray small angle scattering measuring apparatus which concerns on embodiment of this invention. 1 is an external view of an X-ray small angle scattering measurement apparatus according to an embodiment of the present invention. 1 is an external view of an X-ray small angle scattering measurement apparatus according to an embodiment of the present invention. It is a block diagram of the control part of the X-ray small angle scattering measuring apparatus which concerns on embodiment of this invention. It is a figure which shows X-ray scattering intensity when the sample 1 is measured using a X-ray small angle scattering method. It is a figure which shows X-ray scattering intensity when the sample 2 is measured using a X-ray small angle scattering method.

  An X-ray small angle scattering measuring apparatus according to the present invention includes an X-ray source that emits X-rays, a monochromator that emits X-rays emitted from the X-ray source as monochromatic parallel light, and X-rays that are emitted. A slit that defines the X-ray emission region of the monochromator so that the line irradiates the linear region, a transport unit that transports a flat stage on which the sample can be mounted to a position where the sample is irradiated with the X-ray, A two-dimensional detector that detects an X-ray scattering image formed by scattering from a linear region of the sample that has been irradiated with X-rays, and the transport section intersects the longitudinal direction of the linear region The planar stage is transported in a direction to be moved.

  The X-ray small angle scattering measurement apparatus of the present invention is preferably used for measurement of structures including nano-sized particles and structures. This structure is particularly preferably a planar structure, and particles and structures having a size of 10 nm or less are preferable. Further, the X-ray small angle scattering measuring apparatus of the present invention may be used for measuring a structure in which particles or the like are dispersed in a liquid or solid. For example, you may use for the measurement of a semiconductor nanoparticle, and it is good also considering the thing by which the semiconductor nanoparticle was disperse | distributed in the liquid and solid (for example, a gel, a fluid).

  The X-ray small angle scattering measuring apparatus of the present invention employs the X-ray small angle scattering method, and can be used in a small angle region where the scattering angle appears at about 10 degrees or less. In the small-angle region, unlike the diffraction phenomenon at the medium angle that appears corresponding to the crystal structure, scattering appears depending on the size and shape of the particles. For example, if the electron density in the semiconductor nanoparticles diffused in the sample is known, the size of the particles and the spatial density of the nanoparticles can be known. Therefore, the X-ray small angle scattering method is optimal for device evaluation. It becomes a method.

  For example, the X-ray small angle scattering measuring apparatus of the present invention can be used for measuring a device composed of nanoparticles dispersed in a two-dimensional matrix (such as a light emitting element in which semiconductor nanoparticles are dispersed). In this case, since the size of the nanoparticles and the distribution in the plane (planar distribution in the device) can be measured, a light-emitting device with excellent reliability can be easily manufactured. Moreover, by using the X-ray small angle scattering measurement apparatus of the present invention, measurement can be performed without destroying the device, and measurement can be performed without affecting the structure of the semiconductor nanoparticles. That is, the X-ray small angle scattering measuring apparatus of the present invention is excellent as a nondestructive inspection. In the X-ray small angle scattering method, since there is a clear relationship between the angle corresponding to the peak of the scattering intensity and the size of the particle, the size of the particle contained in the sample can be determined by measuring the X-ray scattering intensity in the small angle region. Can be requested. Therefore, by measuring the size of the particles dispersed in the plane of the light emitting device and evaluating how the size of the particles are distributed in the plane, evaluation as a light emitting device (for example, , Evaluation of wavelength characteristics) becomes possible.

In addition, the X-ray small angle scattering measurement apparatus of the present invention may be an apparatus that is also used as a measurement method related to other X-ray reflection (or transmission). For example, an apparatus that is also used as an X-ray apparatus diffraction method may be used. However, the X-ray apparatus diffraction method is effective when it is assumed that there are a finite number of lattice planes having a plane interval corresponding to the Bragg angle without any disturbance. When there is distortion, there is a limit to the application of the following formula (1) relating to the X-ray apparatus diffraction method.
D = K · λ / B · cos θ (1)
(D is the size [nm] of the particles included in the measurement object, λ is the wavelength [nm] of the X-ray used for diffraction, θ is the Bragg angle [deg], and B is the half-width of the diffraction peak at the Bragg angle [deg]. K is a weighting coefficient, and assuming that the particles included in the measurement object have an ideal spherical shape, K is 0.94 when an average value is obtained by using D as a volume weighted average diameter. Value.)

  In general, since semiconductor nanoparticles have a higher proportion of atoms near the surface than general crystals, there is a possibility that the crystal structure is distorted near the surface due to the influence of an electrostatic potential different from that in the crystal. In that case, in Formula (1), both the reduction of the crystal size and the distortion of the crystal exist as the cause of the expansion of the full width at half maximum. Therefore, when the measurement object is semiconductor nanoparticles dispersed in the device, Limitations apply to the application of X-ray apparatus diffraction to nanoparticles. For this reason, in the measurement of semiconductor nanoparticles, the X-ray small angle scattering method is preferable as a method for measuring the particle size simply and quantitatively.

  In an embodiment of the present invention, the apparatus further includes a control unit that controls the transport unit and the two-dimensional detector, and the control unit is configured to maintain the X-ray incident angle on the sample at a constant angle. The flat stage may be transported by a transport unit, and the X-ray scattering image may be detected by the two-dimensional detector each time the transport unit moves a certain distance. According to this embodiment, the data for calculating the X-ray scattering intensity distribution with respect to the scattering angle for each position in the longitudinal direction in the linear region of the sample is automatically acquired every time the transport unit moves a certain distance. Can be provided. For this reason, the two-dimensional X-ray scattering intensity distribution in the sample can be obtained. Therefore, for example, the size of nano-sized particles in the sample can be measured, and the two-dimensional distribution of the particles in the sample can be measured.

  In the embodiment of the present invention, the certain distance may be greater than or equal to the slit width. According to this embodiment, the control unit causes the two-dimensional detector to detect the X-ray scattering image every time the transport unit moves a distance equal to or larger than the slit width. The position of the sample irradiated in the linear region by X-rays differs before and after. For this reason, the data of the X-ray-scattering image in which the position of a sample does not overlap can be acquired. Therefore, a more accurate two-dimensional X-ray scattering intensity distribution can be obtained. Further, according to this embodiment, it is possible to acquire data for calculating the X-ray scattering intensity distribution at least in the slit width unit.

  Here, the width of the slit is a width that defines the X-ray emission region, and includes a region where the slit emits X-rays. That is, it includes a region where X-rays pass through the material constituting the slit and is not defined by the physical slit width. For example, even if the slit includes a filter that attenuates X-rays, the width (short-side direction) of the region where the X-rays are emitted from the slit constitutes the width of the slit.

  The width of the slit may be the width when the slit is projected onto the sample by X-rays. In this case, the width of the slit projected onto the sample by the X-ray may be calculated from the positional relationship between the X-ray source and the monochromator and the sample on the stage, and the slit width may be obtained.

In an embodiment of the present invention, an X-ray scattering intensity distribution with respect to a scattering angle is calculated based on an X-ray intensity distribution of the X-ray scattering image and position information in the two-dimensional detector, and a linear region of the sample is obtained. You may provide the calculating part which calculates for every position of the longitudinal direction in.
Here, the position in the longitudinal direction of the linear region of the sample is the position of the sample in the longitudinal direction of the slit when the slit is projected onto the sample by X-rays, and is a one-dimensional position.
According to this embodiment, it is possible to provide an apparatus that automatically calculates the X-ray scattering intensity distribution with respect to the scattering angle indicated by each position in the longitudinal direction in the linear region of the sample.

  In the embodiment of the present invention, the X-ray scattering intensity with respect to the scattering angle based on the X-ray intensity distribution of the X-ray scattering image, the position information in the two-dimensional detector, and the position information transferred by the transfer unit. You may provide the calculating part which calculates distribution as planar distribution of the said sample. According to this embodiment, not only the X-ray scattering intensity distribution with respect to the scattering angle indicated by each position in the longitudinal direction in the linear region of the sample, but also the X-ray scattering intensity distribution of the sample in the distance unit transported by the transport unit for a certain distance. Can be provided.

  Further, according to an embodiment of the present invention, an X-ray scattering intensity distribution with respect to a scattering angle is calculated based on an X-ray intensity distribution of the X-ray scattering image and position information in the two-dimensional detector, and a linear region of the sample is obtained. Further, a calculation unit that calculates each position in the longitudinal direction of the sample and further calculates a planar distribution of the sample based on the position information transferred by the transfer unit may be used.

  In this embodiment, the control unit causes the two-dimensional detector to detect the intensity of background X-rays, and the calculation unit calculates the background X-rays based on the X-ray intensity of the X-ray scattered image. May be subtracted to calculate the X-ray scattering intensity distribution for the sample. According to this embodiment, a more accurate X-ray scattering intensity distribution can be obtained from the X-ray intensity of the X-ray scattering image detected by the two-dimensional detector.

  In this embodiment, the two-dimensional detector may be a CCD in which pixels are two-dimensionally arranged, or may be an imaging plate. The two-dimensional detector may be any device that can measure the X-ray intensity and has the detector arranged two-dimensionally.

Further, the measuring method for measuring the X-ray small angle scattering of the sample of the present invention uses the X-ray small angle scattering measuring apparatus of the present invention to carry out the conveyance so that the incident angle of the X-ray to the sample is kept constant. The flat stage is transported by a part, and the X-ray scattering image is detected by the two-dimensional detector each time the transport part moves a certain distance, and X-ray small angle scattering of the sample is measured. And
According to this invention, for each position in the longitudinal direction in the linear region of the sample, data for calculating an X-ray scattering intensity distribution with respect to a scattering angle is acquired every time the transport unit moves a certain distance. A two-dimensional X-ray scattering intensity distribution in the sample can be obtained. Therefore, for example, the size of nano-sized particles in the sample can be measured, and the two-dimensional distribution of the particles in the sample can be measured.

Further, the method for measuring the size of the particles contained in the sample of the present invention uses the X-ray small angle scattering measurement apparatus of the present invention to detect the X-ray scattering image by the two-dimensional detector, and Based on the X-ray intensity distribution of the ray-scattered image and the position information in the two-dimensional detector, the X-ray scattering intensity distribution with respect to the scattering angle is calculated for each longitudinal position in the linear region of the sample. Features.
According to this invention, based on the X-ray intensity distribution in the X-ray scattering image detected by the two-dimensional detector, the X-ray scattering intensity distribution with respect to the scattering angle is obtained for each position of the sample in the linear region. Thus, the size of the particles contained in the sample can be measured. For this reason, the sample can be analyzed by obtaining a two-dimensional X-ray scattering intensity distribution in the sample by moving the sample in the direction intersecting with the longitudinal direction of the linear region. Therefore, by measuring a sample in which nano-sized particles or the like are dispersed, the size of the nano-sized particles at each position in the sample can be analyzed, and the two-dimensional distribution of the particles in the sample can be analyzed. .

  In addition to the measurement method for measuring the X-ray small angle scattering of the sample of the present invention, the embodiment related to the analysis method for analyzing the sample of the present invention is an X-ray of the X-ray scattering image measured by the measurement method. Based on the intensity distribution, the position information in the two-dimensional detector and the position information transported by the transport unit, the X-ray scattering intensity distribution with respect to the scattering angle is calculated as a planar distribution of the sample, The size of the contained particles may be measured. According to this embodiment, the two-dimensional X-ray scattering intensity distribution indicated by the sample can be obtained.

  Hereinafter, the X-ray small angle scattering method will be described, and the present invention will be described in detail using embodiments shown in the drawings.

(Apparatus according to the embodiment)
An X-ray small angle scattering measurement apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 are conceptual diagrams for explaining the optical system of the X-ray small angle scattering measurement apparatus according to this embodiment. 3 and 4 are external views of the X-ray small angle scattering measuring apparatus according to this embodiment. FIG. 1 is a perspective view of the optical system of this apparatus, and FIG. 2 is an optical top view of this apparatus. FIG. 3 is a top view of the device, and FIG. 4 is a side view of the device.

  As shown in FIG. 1, the X-ray small angle scattering measurement apparatus according to this embodiment is configured by an optical system including an X-ray source 1, a monochromator 2, a slit 3, and a two-dimensional detector 6. Yes.

  The X-ray source 1 is an X-ray source with a line focus, and uses an X-ray tube. In this embodiment, since the X-rays irradiate the sample 5 in a linear region through the slit 3, a line-focused X-ray source may be used. For example, an X-ray tube having a line focal point that emits Kα rays that are characteristic X-rays of X-ray tube copper is used. Since the X-rays emitted from the X-ray source are converted into parallel light in the monochromator 2, an X-ray source having an appropriate divergence angle may be selected in consideration of the characteristics of the monochromator 2.

  Further, the monochromator 2 emits X-rays by making the X-rays radiated from the X-ray source monochromatic and making them parallel light. In this embodiment, a multilayer film type X-ray mirror is used as the monochromator 2. A commercially available monochromator 2 may be selected according to the wavelength characteristics of X-rays emitted from the X-ray source. For example, a monochromator such as a multilayer film mirror can be used.

The slit 3 defines an X-ray emission region so that X-rays emitted from the monochromator irradiate the linear region on the sample. This emission region is determined by the angle ω at which X-rays enter the sample 5 and the slit width d. That is, when the effective light beam width of the X-rays incident on the sample 5 is d _S , the light beam width d _S can be expressed by the following equation.
d _S = d / sin ω (Equation 2)
This light beam width determines the measurement area width in the A direction of each point in the sample (measurement width of the two-dimensional detector 6 when the angle ω is a certain value). For this reason, it is preferable that the ray width d of the X-rays can be adjusted by configuring the slit so that the width d (opening width) of the slit can be changed. For example, a device that can replace the slit 3 may be used, or a plate that slides so as to cover the opening of the slit 3 may be provided so that the beam width d of the X-ray can be adjusted.

The two-dimensional detector 6 uses a CCD in which pixels (pixels) are two-dimensionally arranged, and the pixels of the CCD are arranged in a matrix in the A and B directions in FIG. The two-dimensional detector 6 has a function of detecting the intensity of X-rays scattered from the sample 5 and detecting the intensity of background X-rays when the sample 5 is irradiated with X-rays. . Since the two-dimensional detector 6 outputs the X-ray intensity value detected by each pixel and the position information of each pixel, the apparatus according to this embodiment distributes the X-ray scattering intensity for both the positions A and B. It can be detected as matrix data as a function.
For the two-dimensional detector 6, for example, an imaging plate may be used.

  As shown in FIGS. 1 and 2, the two-dimensional detector 6 is arranged so that the direction in which pixels (pixels) are arranged (direction B in FIG. 1) is parallel to the longitudinal direction of the slit. With this arrangement, the X-rays detected by the two-dimensional detector 6 are X-rays scattered from the sample 5, and therefore the position of each pixel in the B direction in the two-dimensional detector 6 Will match the position. Further, the position of each pixel in the A direction in the two-dimensional detector 6 corresponds to the scattering angle 2θ. Therefore, the X-ray scattering intensity from each position in the Y direction on the sample can be easily calculated from the X-ray intensity detected by each pixel of the two-dimensional detector 6. That is, the X-ray scattering intensity distribution with respect to the scattering angle indicated by each position can be easily calculated.

  The two-dimensional detector 6 may introduce a solar slit for preventing vertical divergence between the stage 4 (or the sample 5). As a result, the scattering angle in the vertical direction from the sample is increased, and when the scattering from each point in the sample is mixed in the Y direction, an error in peak calculation due to mixing of X-ray scattering can be prevented. The position of the solar slit may be between the two-dimensional detector 6 and the stage 4 (or the sample 5), and may be a location after the sample has been subjected to X-ray scattering.

  Further, as shown in FIGS. 3 and 4, the apparatus according to this embodiment includes a stage 4 on which a sample can be mounted, and a transfer unit 70 that transfers the stage 4 to a position where the sample 5 is irradiated with X-rays. It has.

  The stage 4 is formed of a plate-like body, and is configured so that the sample 5 can be held on one surface thereof. In the embodiment shown in FIGS. 3 and 4, the sample 5 is configured to be held by a holder 41 on the surface (side surface in FIG. 3) of the plate-like body constituting the stage 4, and the stage 4 is configured to be a transport unit (X-axis slider). (Including) 70).

  The transport unit 70 includes an X-axis slider 70, a Y-axis slider 72, a rotation unit 74, a two-dimensional detection unit rotation unit 76, and a slider 78. The X-axis slider 70, the Y-axis slider 72, and the rotating unit 74 convey the stage 4, and the two-dimensional detection unit rotating unit 76 and the slider 78 convey the two-dimensional detector 6.

  Further, the X-axis slider 70 is configured to be driven by a motor 71 and transport the stage 4. Further, the X-axis slider 70 is installed on a Y-axis slider 72 that is driven (moved) by a motor 73. The X-axis slider 70 is provided to adjust the position so that the sample 5 mounted on the stage 4 is irradiated with X-rays, and the Y-axis slider 72 is connected to the sample 5 mounted on the stage 4 and the X-axis. It is provided to adjust the height position of the line unit 10 and the two-dimensional detector 6. By moving the X-axis slider 70 and the Y-axis slider 72, adjustment is performed so that a desired position of the sample 5 is irradiated with X-rays.

  The rotating unit 74 is configured to rotate by being driven by a motor 75, and is configured to be rotatable with respect to the X-ray unit 10 (unit storing the X-ray source 1) fixed to the apparatus main body 100. ing. The rotating unit 74 is provided to adjust the angle ω (the above formula (2)) at which X-rays enter the sample 5 mounted on the stage 4. Since the Y-axis slider 72 is installed on the rotating unit 74, X-rays emitted from the X-ray unit 10 through the stage 4, the X-axis slider 70, and the Y-axis slider 72 by rotating the rotating unit 74. Is adjusted to enter the sample 5 at a desired angle ω.

  The angle ω adjusted by the rotating unit 74 is configured to be able to rotate about 1 degree from the position where the X-axis slider 70 and the stage 4 and the X-ray radiated and emitted parallel by the monochromator 2 are parallel. Has been. Since the X-ray small angle scattering measurement method requires that the scattered X-rays reach the two-dimensional detector 6 without passing through the sample, the angle ω, that is, the angle ω at which the X-rays enter the sample 5 is 1. Be less than or equal to degrees. For this reason, for example, the X-axis slider 70 and the stage 4 are configured to be parallel to the X-rays irradiated from the X-ray unit 10 (the unit in which the X-ray source 1 is stored), and the rotating unit rotates about 1 degree. What is necessary is just to be comprised as possible.

  The two-dimensional detection unit rotation unit 76 is configured to rotate separately from the rotation unit 74 on which the stage 5 is installed, and the two-dimensional detector 6 is connected to the two-dimensional detection unit rotation unit 76 via the slider 78. It is provided above. The two-dimensional detection unit rotation unit 76 is driven and rotated by a rotation mechanism (including a motor) 751, and the position of the two-dimensional detector 6 can be adjusted by the rotation mechanism 751. The rotation of the two-dimensional detection unit rotation unit 76 is configured such that the rotation center rotates about the same point as the rotation unit 74 (the rotation center is shared), and the sample on the stage 4 is rotated by the rotation. 5 and the two-dimensional detector 6 are formed so as not to deviate from each other.

  The slider (conveyance unit) 78 is installed on the two-dimensional detector rotation unit 76, and the two-dimensional detector 6 is provided on the slider (conveyance unit) 78.

  When the X-ray scattering angle from the sample 5 is large and the X-ray scattering peak appears beyond the arrangement range of the pixels of the two-dimensional detector 6, the two-dimensional detection unit rotating unit 76 and the slider (conveying unit) 78 are X-rays. It is arranged to adjust the position of the two-dimensional detector 6 so that the scattering peak falls within this arrangement range. The two-dimensional detector rotating unit 76 and the slider (conveying unit) 78 are rotated or moved to adjust the two-dimensional detector 6 to a desired position.

  Here, the relationship between the conveyance part 70 (X-axis slider 70, Y-axis slider 72) and the slit 3 is demonstrated. Since the slit 3 defining the X-ray emission region is arranged so that its longitudinal direction is the S direction shown in FIG. 4 (a direction parallel to the movable direction of the Y-axis slider 72), X The long side direction (the S2 direction in FIG. 4) of the linear region (the projected image of the slit 3 by X-rays) where the line irradiates the sample 5 and the direction in which the X-axis slider 70 can move (the X direction in FIG. 4). Are orthogonal. The slit 3 is arranged so that the longitudinal direction (the S direction in FIG. 4) and the direction in which the pixels of the two-dimensional detector 6 are arranged (the B direction in FIG. 4) are parallel. Therefore, as described above, the Y direction of the sample and the B direction of the two-dimensional detector 6 have a corresponding relationship.

  The longitudinal direction of the slit defining the X-ray emission region does not have to coincide with the S direction shown in FIG. 4, but the linear region in which the X-ray irradiates the sample 5 (projection of the slit 3 by X-rays). The longitudinal direction of the slit or the movable direction of the X-axis slider 70 may be set so that the long side direction of the image) and the movable direction of the X-axis slider 70 intersect. By moving the X-axis slider 70, the X-ray intensity can be measured by scanning the sample 5 with the width in the longitudinal direction of the slit (the X-ray intensity scattered by the sample in a direction other than the longitudinal direction of the slit can be measured). ). In this case, since the X direction and the Y direction described above are not orthogonal to each other, the X-ray scattering intensity from each position in the Y direction on the sample is determined from the X-ray intensity detected by each pixel of the two-dimensional detector 6. Must be calculated in consideration of this angular relationship.

(Control unit and calculation unit)
As shown in FIG. 4, the apparatus according to this embodiment includes a control unit 8 in the apparatus main body 100. The control unit 8 is electrically connected to a CPU (calculation unit) 9 outside the apparatus. This apparatus is configured such that the control unit 8 and the CPU (calculation unit) 9 automatically perform the operation described above, calculate the X-ray scattering intensity distribution, and analyze the sample. FIG. 5 shows a connection relationship (block diagram) between the control unit 8 and the CPU (calculation unit) 9. FIG. 5 is a block diagram of a control unit of the X-ray small angle scattering measurement apparatus according to the embodiment.

  As shown in FIG. 5, the control unit 8 includes an X-axis motor 71, a Y-axis motor 73, a θ-axis motor 75, a two-dimensional detector motor 751, a two-dimensional detector 6, and an X-ray source unit 10 via wiring. It is connected to (X-ray source 1) and configured to control these operations. The control unit 8 is connected to the CPU 9 via wiring. The X-axis motor 71, Y-axis motor 73, θ-axis motor 75, and two-dimensional detector motor 751 are connected to the X-axis slider 70, Y-axis slider 72, θ-axis rotating unit 74, and two-dimensional detector rotating unit 76, respectively. These are configured to drive these.

  The control unit 8 causes the X-axis slider 70 to convey the stage so that the incident angle of the X-rays to the sample is kept constant. That is, the control unit 8 drives the X-axis motor 71 and moves the X-axis slider 70 while the θ-axis motor 75 is stopped and the rotation unit 74 is not rotated (fixed at a fixed angle). Further, the control unit 8 causes the two-dimensional detector 6 to detect the X-ray scattering image scattered from the sample 5 every time the X-axis slider 70 is moved by a certain distance. Thereby, the control unit 8 obtains X-ray intensity distribution data of an X-ray scattered image corresponding to the X-axis slider 70.

  The CPU (calculation unit) 9 receives the X-ray intensity distribution data of the X-ray scattered image from the two-dimensional detector, and receives positional information of the pixels (pixels) in the two-dimensional detector and the X-ray intensity of each pixel. From the value, the X-ray intensity at each position in the sample 5 in the longitudinal direction of the linear region irradiated with X-rays, that is, the X-ray scattering intensity distribution with respect to the scattering angle indicated by each position of the sample is calculated.

  When the control unit 8 moves the X-axis slider 70 and moves a certain distance, the CPU (calculation unit) 9 detects X-ray scattering from the two-dimensional detector. The X-ray intensity distribution data of the image is received, and the positional information such as the transport distance of the X-axis slider 70 is received from the control unit 8, and the positional information of the pixels in the two-dimensional detector and the X-ray intensity of each pixel are received. The X-ray scattering intensity distribution with respect to the scattering angle indicated by each position of the line direction of the linear region irradiated with the X-rays of the sample 5 and the direction in which the sample is conveyed is calculated from the value and the position information of the X-axis slider 70. (In other words, the X-ray scattering intensity distribution with respect to the scattering angle is calculated as a planar distribution of the sample).

In calculating the X-ray scattering intensity distribution, the X-ray small angle scattering measuring apparatus may be configured to calculate using the intensity of background X-rays (also referred to as background radiation). For example, the control unit 8 causes the two-dimensional detector 6 to detect the intensity of the background X-ray, and the CPU 9 determines the background X from the X-ray intensity of the X-ray scattered image detected by the two-dimensional detector 6. The X-ray scattering intensity distribution indicated by the sample may be calculated by subtracting the line intensity.
In this embodiment, the control unit 8 and the CPU 9 automatically operate and calculate the apparatus, but this operation and calculation may be performed manually. For example, the operation and usage of the apparatus described below may be performed manually.

(Operation and Usage Method of Apparatus According to Embodiment)
Next, with reference to FIG.3 and FIG.4, operation | movement and the usage method of the apparatus concerning this embodiment are demonstrated.

  First, the sample 5 is fixed to the stage 4 by the holder 41 (step 1).

  Next, the position of the sample 5 is adjusted by the X-axis slider 70 and the Y-axis slider 72 so that the sample 5 is irradiated with X-rays. Further, the rotating unit 74 is adjusted so that the X-ray enters the sample 5 at a small angle (step 2). At this time, the positions of the two-dimensional detection unit rotating unit 76 and the slider 78 are adjusted so that the two-dimensional detector 6 detects X-rays scattered by the sample 5. Up to step 2 is the preparation stage of this apparatus.

  Next, using the apparatus according to this embodiment, the X-axis slider (transport unit) 70 is transported so that the incident angle of the X-rays to the sample 5 is kept constant, and the X-axis slider (transport unit) 70 is transported. Is moved a certain distance (step 3). Here, the fixed distance for moving the X-axis slider (conveying unit) 70 is equal to or greater than the width of the slit. That is, the X-axis slider (conveying unit) 70 is moved in units of the slit width. In the case of this embodiment, the width of the slit means the width when the slit is projected onto the sample by X-rays.

  Next, the X-ray scattering image scattered from the sample 5 is detected by the two-dimensional detector 6 (step 4). Thereby, X-ray scattering intensity data for each position in the longitudinal direction (X direction in FIG. 1) in the linear region of the sample can be obtained in the width unit in which the sample is irradiated with X-rays by the slit. This data is data for calculating the X-ray scattering intensity distribution with respect to the scattering angle.

  Next, in the same manner as described above, the X-axis slider (conveyance unit) 70 is moved by a certain distance so that the incident angle of the X-rays to the sample is kept constant (step 5), and then the two-dimensional type The detector 6 detects the intensity of the X-rays scattered from the sample 5 (step 6). That is, the apparatus performs the same operation as in steps 3 and 4 above. Thereby, data for calculating the X-ray scattering intensity distribution with respect to the scattering angle at each position of the sample can be obtained at a position away from the position measured in steps 4 and 5 above by a certain distance.

  Next, the operations of steps 5 and 6 (that is, steps 3 and 4) are repeated until the moving distance of the X-axis slider exceeds the range to be measured (step 7). Thereby, data for calculating a planar X-ray scattering intensity distribution in the sample can be obtained. In step 3, the X-axis slider (conveyance unit) 70 is moved by a certain distance, but step 4 may be performed without performing step 3.

A sample is analyzed from the data obtained by the method of steps 1 to 7 above. That is, the angle at which X-rays are scattered depends on the region where the electron density of the sample is different (for example, the size of particles contained in the sample). calculate.
As described above, the apparatus according to this embodiment has a relationship in which the Y direction of the sample and the B direction of the two-dimensional detector 6 correspond to each other, and thus steps 4 and 5 (or steps 5 and 6). ), Based on the X-ray intensity distribution of the X-ray scattering image and the positional information in the two-dimensional detector, the X-ray scattering intensity distribution with respect to the scattering angle is converted into the longitudinal position in the linear region of the sample. The sample may be analyzed by calculation every time. In addition, when step 7 is completed, the X-ray intensity distribution of the X-ray scattered image, the positional information in the two-dimensional detector (for example, each pixel position), and the positional information ( The sample may be analyzed by calculating an X-ray scattering intensity distribution with respect to the scattering angle as a planar distribution of the sample based on a multiple of the above-mentioned constant distance and the position of the stage at each step.

(Application of small-angle X-ray scattering to semiconductor nanoparticles)
Next, a case where semiconductor nanoparticles are measured using the X-ray small angle scattering method according to this embodiment will be described.
In general, in the X-ray small angle scattering method, when particles having a size of about 1 to 10 nm dispersed in a uniform medium exist, X-ray scattering occurs due to the difference between the electron density of the particles and the electron density of the medium. It is a method of utilizing. Regarding this X-ray scattering, the angle at which X-rays are scattered depends on the region where there is a difference in electron density, that is, the size of particles in the medium. For this reason, the scattering angle decreases as the particle size increases. In applying this X-ray small angle scattering method, the particles and the medium are required to have uniform electron density in each region. For this reason, the X-ray small angle scattering method is not questioned depending on whether the particle / medium is crystalline or amorphous, or belongs to a solid or liquid phase, and the electron density is uniform. Then, particles having a size of about 1 to 10 nm can be measured.

  Therefore, even when measuring semiconductor nanoparticles, if there is a difference in electron density between the semiconductor nanoparticles and the medium, a scattering peak appears depending on the size of the semiconductor nanoparticles. If Kα ray, which is a characteristic X-ray of copper, is used as the X-ray source, the wavelength is 0.152 nm. Therefore, assuming that 2θ is measured at an angle of 1 to 10 degrees, it is approximately 1 to 10 nm. Can be measured by the X-ray small angle scattering method.

(Demonstration experiment)
FIG. 6 and FIG. 7 show examples in which the particle size of the semiconductor device is measured using the X-ray small angle scattering method. 6 and 7 are diagrams showing the X-ray scattering intensity when a sample in which InP nanoparticles are dispersed in a hexane solvent is measured using the X-ray small angle scattering method. FIGS. 6 and 7 are obtained by measuring Sample 1 and Sample 2, respectively, by the X-ray small angle scattering method. In these measurements, Kα rays were used as the X-rays among the characteristic X-rays of copper. The wavelength of this X-ray is 0.152 nm.
As shown in FIG. 6 and FIG. 7, it can be seen that there are large and wide peak values up to 3.2 degrees and 2.8 degrees, respectively, due to scattering from the semiconductor nanoparticles.
Table 1 shows the particle size (average value of the volume load distribution) obtained from the X-ray small angle scattering method of FIGS. 6 and 7 for these samples. The right column of the table is the fluorescence wavelength of these samples.

  As shown in Table 1, in InP, which is a representative group III-V compound, it can be understood that the fluorescence wavelength shifts from 530 nm to 620 nm when the particle size changes from 3.4 nm to 3.8 nm. It can be understood from Table 1 that the particle size measurement using the X-ray small angle scattering method can be used as a method for evaluating the light wavelength in advance.

  As described above, the X-ray small angle scattering measurement apparatus according to this embodiment irradiates a linear region with X-rays from the position information of the pixels in the two-dimensional detector and the X-ray intensity distribution detected by each pixel. X-ray scattering intensity distribution with respect to the scattering angle indicated by each position of the sample can be obtained. For example, by measuring a device in which InP nanoparticles are dispersed as a sample, the size of InP nanoparticles in a two-dimensional plane of the device can be measured, and the planar distribution of the particles is measured. be able to.

  While the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments. For example, although the monochromator and the slit have been described as the optical system, other optical systems (mirror, prism, vacuum space, etc.) may be included. In addition, various features shown in the embodiments can be combined with each other. When a plurality of features are included in one embodiment, one or more of the features can be appropriately extracted and used alone or In combination, it can be employed in the present invention.

DESCRIPTION OF SYMBOLS 1 X-ray source 10 X-ray source unit 2 Monochromator 3 Slit 4 Sample stage 5 Sample 6 Two-dimensional X-ray detector 7 Transport part 70, 72, 78 Slider (transport part)
74,76 Rotating part (conveying part)
71, 73, 75, 79 Motor (conveyance 8 control unit 9 CPU (calculation unit)
100 Device body

Claims (10)

An X-ray source emitting X-rays;
A monochromator that emits X-rays emitted from an X-ray source as monochromatic parallel light; and
A slit that defines the X-ray emission region of the monochromator so that the emitted X-rays illuminate the linear region;
A transport unit that transports a flat stage on which the sample can be mounted to a position where the sample is irradiated with X-rays;
A two-dimensional detector that detects an X-ray scattering image formed by scattering from a linear region of the sample that has been irradiated with X-rays;
With
The X-ray small angle scattering measurement apparatus, wherein the transport unit transports the planar stage in a direction intersecting with a longitudinal direction of the linear region. The apparatus further includes a control unit that controls the transport unit and the two-dimensional detector,
The plane stage is transported to the transport unit so that the incident angle of X-rays to the sample maintains a constant angle,
The X-ray small angle scattering measurement apparatus according to claim 1, wherein the X-ray scattering image is detected by the two-dimensional detector each time the transport unit moves a certain distance. The X-ray small angle scattering measurement apparatus according to claim 2, wherein the certain distance is equal to or larger than a width of the slit. Based on the X-ray intensity distribution of the X-ray scattering image and the positional information in the two-dimensional detector, the X-ray scattering intensity distribution with respect to the scattering angle is calculated for each longitudinal position in the linear region of the sample. The X-ray small angle scattering measurement apparatus according to claim 1, further comprising a calculation unit. Based on the X-ray intensity distribution of the X-ray scattering image, the positional information in the two-dimensional detector, and the positional information conveyed by the conveying unit, the X-ray scattered intensity distribution with respect to the scattering angle is obtained in a planar manner. The X-ray small angle scattering measurement apparatus according to claim 2, further comprising a calculation unit that calculates the distribution. The control unit causes the two-dimensional detector to detect the intensity of background X-rays,
The X-ray small angle scattering measurement according to claim 4 or 5, wherein the calculation unit subtracts the background X-ray intensity from the X-ray intensity of the X-ray scattering image to calculate an X-ray scattering intensity distribution for the sample. apparatus. The X-ray small angle scattering measurement apparatus according to claim 1, wherein the two-dimensional detector is a CCD or an imaging plate in which pixels are two-dimensionally arranged. Using the X-ray small angle scattering measuring apparatus according to claim 1, the plane stage is transported to the transport unit so that the incident angle of X-rays to the sample is kept constant, and the transport unit is at a constant distance. A measuring method in which the X-ray scattering image of the sample is measured by causing the two-dimensional detector to detect the X-ray scattering image each time it moves. The X-ray scattering image is detected by the two-dimensional detector using the X-ray small angle scattering measurement apparatus according to claim 1, and the X-ray intensity distribution of the X-ray scattering image and the two-dimensional detector are detected. The X-ray scattering intensity distribution with respect to the scattering angle is calculated for each longitudinal position in the linear region of the sample based on the position information, and the size of the particles contained in the sample is measured. An X with respect to a scattering angle based on the X-ray intensity distribution of the X-ray scattering image measured by the measurement method according to claim 8, the positional information in the two-dimensional detector, and the positional information transported by the transport unit. A method of measuring the size of particles contained in a sample by calculating a line scattering intensity distribution as a planar distribution of the sample.

Images