Measurement apparatus, measurement method, and measurement program

Abstract

To provide a measurement apparatus capable of appropriately positioning an electromagnetic wave beam for measurement to a sample being a measuring object.SOLUTION: A measurement apparatus 1 includes: an irradiation part 2 configured to irradiate a sample S with a terahertz wave beam B; a detector 3 configured to detect the terahertz wave beam B from the sample S; an opening member 5 disposed between the irradiation part 2 and the detector 3, and equipped with an opening 51 allowing the terahertz wave beam B to pass; and a drive part 6 configured to integrally drive the opening member 5 and the sample S in a direction intersecting a direction of travel of the terahertz wave beam B so that a strength of the terahertz wave beam B to be detected by the detector 3 becomes higher.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a measuring device that uses electromagnetic waves such as terahertz waves. [Background technology]

[0002] Patent Document 1 describes Tera (10 12 ) An apparatus is disclosed for measuring the internal state of a sample using terahertz waves, which are electromagnetic waves having a frequency in the hertz range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6843397 Summary of the Invention [Problem to be solved by the invention]

[0004] Terahertz waves, which have intermediate properties between radio waves and light, have a long wavelength (or low frequency) compared to light, so there is no established method for visually checking or confirming the optical axis, as is the case with visible light and infrared light, which are commonly used in conventional optical measurements. This poses the issue of how difficult it is to accurately position the terahertz wave beam used for measurement relative to the sample to be measured.

[0005] The present disclosure has been made in consideration of these circumstances, and has an object to provide a measurement device etc. that can appropriately position a measurement electromagnetic wave beam with respect to a sample that is the object of measurement. [Means for solving the problem]

[0006] In order to solve the above problems, a measurement device of one aspect of the present disclosure includes an irradiation unit that irradiates an electromagnetic beam onto a sample, a detection unit that detects the electromagnetic beam from the sample, an aperture member provided between the irradiation unit and the detection unit and having an opening through which the electromagnetic beam can pass, and a drive unit that drives the aperture member together with the sample in a direction intersecting the propagation direction of the electromagnetic beam so that the intensity of the electromagnetic beam detected by the detection unit is increased.

[0007] In this aspect, the aperture member is driven integrally with the sample in a direction intersecting the traveling direction of the electromagnetic beam so that the intensity of the electromagnetic beam detected by the detection unit is increased, and therefore the sample is appropriately positioned with respect to the electromagnetic beam so that more of the electromagnetic beam passes through the opening in the aperture member and is detected by the detection unit.

[0008] Another aspect of the present disclosure is a measurement method, which includes the steps of: irradiating an electromagnetic beam onto a sample by an irradiation unit; detecting the electromagnetic beam from the sample by a detection unit; and driving an aperture member provided between the irradiation unit and the detection unit and having an opening through which the electromagnetic beam can pass, by a drive unit that drives the aperture member integrally with the sample in a direction intersecting the traveling direction of the electromagnetic beam so that the intensity of the electromagnetic beam detected by the detection unit increases.

[0009] Any combination of the above components, or any conversion of these components into a method, device, system, recording medium, computer program, or the like, is also encompassed by the present disclosure. Effect of the Invention

[0010] According to the present disclosure, a measurement electromagnetic beam can be appropriately positioned relative to a sample to be measured. [Brief description of the drawings]

[0011] [Figure 1] 1 shows a schematic configuration of a measuring device. [Diagram 2]11 is a flowchart showing an example of an xy alignment and measurement process by the measurement device. [Diagram 3] Schematic showing the diffraction of a terahertz beam by an aperture, which can be caused by small xy movements of the sample and aperture member. [Figure 4] 1 illustrates a schematic diagram of the distribution of frequency components in a broadband terahertz wave beam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following, a form for carrying out the present disclosure (hereinafter also referred to as an embodiment) will be described in detail with reference to the drawings. In the description and / or drawings, identical or equivalent components, members, processes, etc. will be given the same reference numerals, and duplicated descriptions will be omitted. The scale and shape of each part shown in the drawings are set for convenience in order to simplify the description, and are not to be interpreted as being limiting unless otherwise specified. The embodiment is an example, and does not limit the scope of the present disclosure in any way. All features and their combinations presented in the embodiment are not necessarily essential to the present disclosure. The embodiment is presented for convenience, decomposed into components for each function and / or each functional group that realizes it. However, one component in the embodiment may actually be realized by a combination of multiple components as separate entities, and multiple components in the embodiment may actually be realized by one component as an integrated entity.

[0013] 1 is a schematic diagram showing a configuration of a measuring device 1 according to an embodiment of the present disclosure. The measuring device 1 irradiates an arbitrary electromagnetic wave onto a sample S and / or an object (not shown) of the same type as the sample S (hereinafter, collectively referred to as the sample S, except when it is necessary to distinguish the sample S from the object), in order to inspect the characteristics and internal state of the sample S and / or the object. The specific measurement method and purpose by the measuring device 1 are arbitrary, but for example, by irradiating the sample S with an electromagnetic wave beam (electromagnetic wave beam) B, the refractive index anisotropy and / or the dielectric constant anisotropy of the sample S can be measured, and the internal state of the sample S, such as residual stress, distortion, orientation, and deterioration, can be evaluated.

[0014] In this embodiment, Tera (10 12 A beam of terahertz waves (terahertz wave beam) B, which are electromagnetic waves having a frequency in the 10 GHz (10 GHz) range, is irradiated onto a sample S. Terahertz waves have intermediate properties between low-frequency radio waves and high-frequency light, and can pass through polymeric materials that cannot be penetrated by ordinary light, for example, like radio waves. Terahertz waves are also subject to strong effects such as absorption due to the inherent vibrations of biomolecules and other polymeric materials. Due to these characteristics, terahertz waves are suitable for use in spectroscopic measurement (spectral measurement) of polymeric materials. However, the measurement device according to the present disclosure can also measure any light with a higher frequency than terahertz waves or any radio wave with a lower frequency than terahertz waves (for example, in the 10 GHz (10 GHz) range). 9 ) Gigahertz waves, which have frequencies in the hertz range, can be used instead of or in addition to terahertz waves.

[0015] According to the measurement device 1 using the terahertz wave beam B as an electromagnetic wave beam, various characteristics and internal states of the sample S can be measured through detection of the terahertz wave beam B irradiated to the sample S. For example, the refractive index anisotropy, dielectric constant anisotropy, absorbance, residual stress, distortion, orientation, internal structure, deterioration, and the like of the sample S can be measured by the measurement device 1. Note that, for example, in order to measure the refractive index anisotropy and dielectric constant anisotropy of the sample S, polarization measurement may be performed using a plurality of types of terahertz wave beams B having different polarizations (for example, horizontal polarization and vertical polarization). On the other hand, for example, in measuring the absorbance of the sample S, a single terahertz wave beam B may be used.

[0016] FIG. 1 shows a schematic configuration for a preliminary measurement performed by the measuring device 1 on a sample S (or, as described later, alignment of the terahertz wave beam B and the sample S performed before the preliminary measurement). Here, the preliminary measurement is a measurement performed preliminarily on the sample S in order to appropriately set various measurement parameters used in a main measurement on a typically large number of objects (not shown) of the same type as the sample S. In the main measurement on the object of the same type as the sample S, the measuring device 1 measures the terahertz wave beam B after it is irradiated on the object, based on various measurement parameters set through the preliminary measurement. Note that the configuration of FIG. 1 may be applied to a main measurement performed by the measuring device 1 on an object of the same type as the sample S (or alignment of the terahertz wave beam B and the object performed before the main measurement, as described later).

[0017] The sample S and the object are "same type" means that they are similar to the extent that a meaningful measurement can be performed using common measurement parameters in the measurement device 1. For example, when the sample S and the object are made of substantially the same material and formed to substantially the same shape and thickness (dimensions through which the terahertz wave beam B passes), the two can be said to be "same type". Similarly, when the sample S and the object are substantially the same product (e.g., resin molded product) manufactured by substantially the same manufacturing device (e.g., injection molding machine) and / or substantially the same manufacturing method, the two can be said to be "same type". In this way, the sample S and the object may belong to the same product group. Also, the sample S may be one or more small products extracted from the product group for preliminary measurement.

[0018] In FIG. 1, the measuring device 1 includes an irradiation unit 2, a detection unit 3, a support unit 4, an aperture member 5, a drive unit 6, and an aperture control unit 7. As long as the measuring device 1 can achieve at least some of the actions and / or effects described below, some of these components and / or functional blocks may be omitted. These components and / or functional blocks may be realized by the cooperation of hardware resources such as a central processing unit of a computer, a memory, an input device, an output device, and peripheral devices connected to the computer, and software executed using them. Regardless of the type of computer or the installation location, each of the above functional blocks may be realized by the hardware resources of a single computer, or may be realized by a combination of hardware resources distributed among multiple computers.

[0019] The irradiation unit 2 irradiates the sample S with a terahertz wave beam B as an electromagnetic wave beam. The terahertz wave beam B is irradiated to a predetermined measurement area A on the sample S. Here, as described later, the optical axis or central axis of the terahertz wave beam B, which is illustrated typically by a dotted line, and the measurement position P, which is the central position of the measurement area A, are aligned by the driving unit 6. Although not shown, the terahertz wave beam B spreads to a substantially constant beam diameter centered on the optical axis representing its path or traveling direction, and typically has a substantially circular cross section. The measurement area A on the sample S may be interpreted as an area on the sample S irradiated with the terahertz wave beam B thus spread in a planar or circular shape centered on the optical axis. As described later, an aperture member 5 may be placed in front of the sample S. However, when measuring the sample S, the aperture diameter in the aperture member 5 is set to be significantly larger than the beam diameter of the terahertz wave beam B, so that the aperture member 5 does not substantially affect the terahertz wave beam B and / or the measurement area A.

[0020] The detection unit 3 detects the terahertz wave beam B from the measurement position P and / or the measurement area A on the sample S. In the illustrated example, the detection unit 3 is provided on the opposite side of the sample S as the measurement target from the irradiation unit 2, and therefore detects the terahertz wave beam B that has passed through the sample S. However, the detection unit 3 may be provided on the same side of the sample S as the irradiation unit 2, and detect a terahertz wave beam or other electromagnetic beam reflected by the sample S. By detecting the terahertz wave beam B irradiated to the sample S by the irradiation unit 2 with the detection unit 3, the measurement device 1 can measure or estimate various characteristics and internal states of the sample S at the measurement position P and / or the measurement area A.

[0021] The support unit 4 integrally supports the sample S as a measurement target and the aperture member 5 described later. The support unit 4 includes an xy stage (xy drive unit) 41 that can drive the sample S and the aperture member 5 integrally in the x direction and / or y direction (hereinafter collectively referred to as the xy direction) in a three-dimensional orthogonal coordinate system (xyz coordinate system) shown in the figure by a drive unit 6 described later. Here, the xy direction is a direction intersecting or perpendicular to the z direction, which is the traveling direction of the terahertz wave beam B. In this way, the xy stage 41 can drive the sample S and the aperture member 5 integrally in the xy direction intersecting the traveling direction of the terahertz wave beam B. Note that one or both of the sample S and the aperture member 5 may be integrally or separately driven in the z direction by the xy stage 41 or another z drive unit (not shown).

[0022] At the top (+y side) of the xy stage 41, the sample S is held via the sample holder 42, and the aperture member 5 is held via the aperture member holder 43. As described later, an aperture 51 is provided in the aperture member 5, and the holding position by the sample holder 42 and / or the aperture member holder 43 is adjusted so that the center of the aperture 51 coincides with a measurement position P, which is the center position of the measurement area A on the sample S, when viewed in the z direction (when viewed in the xy plane). As described later, the sample S and / or the aperture member 5 is driven mainly in the xy direction by the driving unit 6, but the positional relationship in which the measurement position P on the sample S and the center of the aperture 51 on the aperture member 5 coincide with each other when viewed in the z direction is maintained in principle throughout the driving by the driving unit 6.

[0023] The aperture member 5 is provided between the irradiation unit 2 and the detection unit 3 in the same manner as the sample S, and has an aperture 51 through which the terahertz wave beam B can pass. The substantial size of the aperture 51 with respect to the terahertz wave beam B may be controlled by an aperture control unit 7 described later. For example, the diameter (aperture diameter) of the aperture 51 may be controlled by the aperture control unit 7. The aperture member 5 whose aperture diameter is controllable in this manner may be represented as an iris or a diaphragm mechanism. Alternatively, although not shown in the figure, the substantial size of the aperture 51 with respect to the terahertz wave beam B irradiated from the irradiation unit 2 may be controlled by relatively driving the aperture member 5 and / or the irradiation unit 2 in the z direction to control the z direction distance between them.

[0024] The shape of the aperture 51 is arbitrary, but is preferably similar to the xy cross-sectional shape of the terahertz wave beam B, and typically is more preferably approximately circular. In the following exemplary description, the shape of the aperture 51 and the xy cross-sectional shape of the terahertz wave beam B are both circular. For this reason, the shape (or aperture size) of the aperture 51 and the xy cross-sectional shape (or beam size) of the terahertz wave beam B are both uniquely determined by the diameter (also expressed as the aperture diameter for the aperture 51, and as the beam diameter for the terahertz wave beam B). Note that the beam size and / or beam diameter may vary depending on the z-direction position in the terahertz wave beam B, but hereinafter, unless otherwise specified, the beam size and / or beam diameter refers to the beam size and / or beam diameter at the same z-direction position as the aperture 51 for direct comparison with the aperture size and / or aperture diameter.

[0025] In the illustrated example, the aperture member 5 is provided between the irradiation unit 2 and the sample S (before or immediately before the sample S). However, the aperture member 5 may be provided between the sample S and the detection unit 3 (after or immediately after the sample S).

[0026] The driving unit 6 drives the aperture member 5 together with the sample S in a direction (xy direction) intersecting the traveling direction (z direction in FIG. 1) of the terahertz wave beam B. Specifically, the driving unit 6 drives the xy stage 41, which holds the sample S via the sample holder 42 and holds the aperture member 5 via the aperture member holder 43, in the xy direction as described above. At this time, the sample S and the aperture member 5 are driven together by the driving unit 6 while maintaining a positional relationship in which the measurement position P in the sample S and the center of the aperture 51 in the aperture member 5 coincide with each other as viewed in the z direction. Note that the xy stage 41 or another z driving unit (not shown) may drive one or both of the sample S (or the sample holder 42) and the aperture member 5 (or the aperture member holder 43) in the z direction either together or separately.

[0027] The driving unit 6 drives the sample S and the aperture member 5 in the xy directions (xy driving) together to appropriately position the terahertz wave beam B for measurement with respect to the sample S to be measured. For example, the xy driving by the driving unit 6 aligns the optical axis (dotted line) of the terahertz wave beam B with the measurement position P, which is the center position of the measurement area A on the sample S. As described above, the measurement position P on the sample S and the center of the aperture 51 in the aperture member 5 coincide with each other when viewed in the z direction, so that the xy driving by the driving unit 6 causes the optical axis of the terahertz wave beam B to coincide with the center of the aperture 51 in the aperture member 5. In other words, the xy alignment by the driving unit 6 aligns the measurement position P on the sample S and the center of the aperture 51 in the aperture member 5 on the optical axis (z axis) of the terahertz wave beam B.

[0028] The above-mentioned alignment is difficult for terahertz waves for which there is no established method for visually observing or confirming the optical axis. Therefore, in this embodiment, the aperture member 5 and the detection unit 3 are used in the xy alignment by the driving unit 6. A specific example will be described later, but the driving unit 6 drives the aperture member 5 together with the sample S in a direction (xy direction) intersecting the traveling direction (z direction) of the terahertz wave beam B so that the intensity of the terahertz wave beam B detected by the detection unit 3 becomes high.

[0029] The aperture control unit 7 controls the substantial size of the aperture 51 in the aperture member 5 with respect to the terahertz wave beam B during xy alignment through the drive unit 6. For example, the aperture control unit 7 controls the diameter (aperture diameter) of the aperture 51. Alternatively, the aperture control unit 7 may control the substantial size of the aperture 51 with respect to the terahertz wave beam B irradiated from the irradiation unit 2 by relatively driving the aperture member 5 and / or the irradiation unit 2 in the z direction by the xy stage 41 or another z drive unit (not shown) to control the z direction distance between them.

[0030] FIG. 2 is a flowchart showing an example of the process of xy alignment and measurement by the measuring device 1 according to this embodiment. In this figure, for convenience, xy alignment including the first alignment and the second alignment and measurement are shown as a series of processes in one flowchart. However, xy alignment and measurement may be performed as separate processes at separate dates and times. Also, xy alignment may include only either the first alignment or the second alignment. Note that if the result of xy alignment performed on the sample S can be applied as it is to an object (not shown) of the same type as the sample S, xy alignment on the object can be omitted. In this case, the object of the same type as the sample S is positioned with respect to the terahertz wave beam B using the result of xy alignment performed on the sample S. Then, the (main) measurement on the object is performed as it is.

[0031] In the illustrated flowchart, "S" denotes a step or process. S1 to S6 are first alignment processes (first alignment phase), S7 to S9 are second alignment processes (second alignment phase), and S10 to S11 are measurement processes (measurement phase) (preliminary measurement of sample S or main measurement of an object of the same type as sample S).

[0032] In S1 in the first alignment phase, the sample S and the aperture member 5 are aligned. Specifically, the sample S is attached to the upper surface or stage surface of the xy stage 41 via the sample holder 42, and the aperture member 5 is attached to the upper surface or stage surface of the xy stage 41 via the aperture member holder 43. At this time, as described above, the measurement position P of the sample S and the center of the aperture 51 in the aperture member 5 coincide with each other when viewed in the z direction. Such a positional relationship in the xy plane of the sample S and the aperture member 5 is maintained through the subsequent processes S2 to S11. In addition, the aligned sample S and the aperture member 5 are placed on the designed optical axis of the terahertz wave beam B. Since the actual optical axis of the terahertz wave beam B may deviate from the designed optical axis, a subsequent first alignment and / or a second alignment with respect to the actual optical axis is required.

[0033] In S2, the aperture control unit 7 sets the diameter (aperture diameter) of the aperture 51 in the aperture member 5 to a predetermined initial diameter or initial value. This initial diameter can be set arbitrarily, but is preferably equal to or smaller than the beam diameter of the terahertz wave beam B. In addition, it is expected that not only the designed optical axis of the terahertz wave beam B (which coincides with the center of the aperture 51) but also the actual optical axis is included within the aperture 51 determined by this initial diameter.

[0034] In S3, the driving unit 6 drives the xy stage 41 in the xy directions together with the sample S and the aperture member 5 aligned in S1. For example, the driving unit 6 drives or scans the xy stage 41 in the xy directions by Δd1 (in increments of Δd1) as a first driving unit. The first driving unit Δd1 can be set arbitrarily, but is preferably on the order of millimeters (for example, between 1 mm and 10 mm). In S3, it is preferable to scan an xy range corresponding to the circular range of the aperture 51 determined by the aperture diameter set in S2.

[0035] In S4, the driving unit 6 stops the xy stage 41 at the xy position where the intensity of the terahertz wave beam B detected by the detection unit 3 becomes maximum through the xy scanning in Δd1 increments in S3. In this way, it is highly likely that the actual optical axis of the terahertz wave beam B exists at the xy position where the detected beam intensity is maximum (the measurement position P in the sample S and / or the center of the aperture 51 in the aperture member 5).

[0036] In order to further improve the positional accuracy of the actual optical axis of the terahertz wave beam B estimated in S4, in S5 (when it is determined as "No" in S6 described later), the aperture control unit 7 reduces the diameter (aperture diameter) of the aperture 51 in the aperture member 5 by Δr from that set in S2. In this way, the aperture control unit 7 reduces the size of the aperture after the first driving (S3) of the aperture member 5 by the driving unit 6.

[0037] Then, returning to S3 and S4, the position of the actual optical axis of the terahertz wave beam B is further narrowed down for a smaller aperture range (aperture diameter). In this manner, the driver 6 performs the second drive (S3) of the aperture member 5 after the aperture control unit 7 reduces the aperture size (S5).

[0038] In S6, if the aperture diameter set in S2 or S5 is equal to or smaller than the predetermined end value ("Yes"), the first alignment ends. The first alignment obtains an estimation result that the actual optical axis of the terahertz wave beam B exists at the xy position where the xy stage 41 stopped in S4 immediately before that (the measurement position P in the sample S and / or the center of the aperture 51 in the aperture member 5). As described above, in the first alignment as the first positioning process, the first drive unit Δd1 (S3) on the order of millimeters, for example, is used, so the position accuracy of the actual optical axis of the terahertz wave beam B estimated in the final S4 is also on the order of millimeters, equivalent to the first drive unit Δd1.

[0039] In the first alignment as described above, in S3, the driver 6 drives the aperture member 5 together with the sample S in the xy directions so that the intensity of the terahertz wave beam B detected by the detector 3 in S4 increases. In the illustrated example, the position of the actual optical axis of the terahertz wave beam B is narrowed down while the aperture diameter is gradually reduced through S5, so that the possibility of erroneous estimation can be reduced. However, the estimation result in S4 under the initial diameter set in S2 may be the final estimation result of the first alignment (the gradual reduction process of the aperture diameter in S5 is omitted).

[0040] In S7 in the second alignment phase following the first alignment phase, the aperture control unit 7 sets the diameter (aperture diameter) of the aperture 51 in the aperture member 5 to be larger than the beam diameter of the terahertz wave beam B. Here, it is preferable that the aperture diameter is set slightly larger than the beam diameter. For example, the minute amount ε (i.e., aperture diameter = beam diameter + ε), which is the difference between the aperture diameter and the beam diameter, is smaller than the first drive unit Δd1 and the positional accuracy (for example, on the order of millimeters) in the first alignment as the first positioning process, and is preferably set on the order of micrometers. As will be described later, the order of this minute amount ε is equivalent to the order of the second drive unit Δd2 and the positional accuracy in the second alignment as the second positioning process.

[0041] In S8, the driving unit 6 drives the xy stage 41 in the xy directions together with the sample S and the aperture member 5 aligned in S1. For example, the driving unit 6 drives or scans the xy stage 41 in the xy directions by Δd2 (in increments of Δd2) as a second driving unit. The second driving unit Δd2 can be set arbitrarily, but is preferably smaller than the first driving unit Δd1 (for example, on the order of millimeters) and on the order of micrometers (for example, between 1 μm and 100 μm). In S8, it is preferable to scan an xy range corresponding to the circular range of the aperture 51 determined by the aperture diameter set in S7.

[0042] The reason why the aperture diameter is set to be slightly larger than the beam diameter in S7 is to effectively manifest the effect of diffraction of the terahertz wave beam B by the aperture 51 in the subsequent minute xy movement of the sample S and the aperture member 5 in S8. Fig. 3 shows a schematic diagram of the diffraction of the terahertz wave beam B by the aperture 51 that may occur by the minute xy movement of the sample S and the aperture member 5.

[0043] In the example of FIG. 3, the irradiation unit 2 and the detection unit 3 are configured by photoconductive antennas having substantially the same configuration. This photoconductive antenna is configured by, for example, a semiconductor substrate and a collimation lens, which is a hemispherical lens or a super hemispherical lens, provided on the semiconductor substrate. The terahertz wave beam B emitted by the photoconductive antenna as the irradiation unit 2 is collected and irradiated to the measurement area A and / or the measurement position P (not shown in FIG. 3) on the sample S through an appropriate optical system such as two parabolic mirrors 81 and 82 and an aperture 51 (not shown in FIG. 3) in the aperture member 5. In addition, the terahertz wave beam B transmitted through the sample S is irradiated to the photoconductive antenna as the detection unit 3 through an appropriate optical system such as two parabolic mirrors 83 and 84.

[0044] In the terahertz wave beam B' indicated by a solid line after transmitting through the sample S, the center of the opening 51 (iris) coincides with the optical axis of the terahertz wave beam B', and the terahertz wave beam B' does not substantially interfere with the edge of the opening 51, so that there is substantially no diffraction due to the edge of the opening 51. In this way, the spread of the terahertz wave beam B' irradiated to the detection unit 3 is suppressed, so that in the illustrated example, substantially the entire terahertz wave beam B' is detected by the detection unit 3.

[0045] In contrast, in the terahertz wave beam B″ indicated by a dotted line after passing through the sample S, the center of the opening 51 (iris) is slightly (for example, on the order of micrometers) misaligned with the optical axis of the terahertz wave beam B″, and the terahertz wave beam B″ substantially interferes with the edge of the opening 51, so that diffraction by the edge of the opening 51 substantially occurs. In this way, the diffracted terahertz wave beam B″ is irradiated to the detection unit 3 in a state wider than the terahertz wave beam B' not accompanied by diffraction. In the illustrated example, a part of the outer periphery of the terahertz wave beam B″ is not irradiated to the detection unit 3. As a result, the detection intensity of the terahertz wave beam B″ accompanied by diffraction due to insufficient alignment by the detection unit 3 is significantly lower than the detection intensity of the terahertz wave beam B' not accompanied by diffraction by the detection unit 3.

[0046] As described above, by utilizing the diffraction of the terahertz wave beam B caused by minute xy movement of the sample S and the aperture member 5, alignment on the order of the minute amount ε or the second movement unit Δd2, such as on the order of micrometers, can be achieved.

[0047] Specifically, in S9, the driver 6 stops the xy stage 41 at the xy position where the intensity of the terahertz wave beam B detected by the detector 3 becomes maximum through the xy scanning in Δd2 increments in S8. In this way, it can be said that the actual optical axis of the terahertz wave beam B exists at the xy position where the detected beam intensity is maximum (the measurement position P in the sample S and / or the center of the aperture 51 in the aperture member 5). In this S9, the second alignment ends. In the second alignment as described above, similarly to the first alignment described above, in S8, the driver 6 drives the aperture member 5 in the xy direction together with the sample S so that the intensity of the terahertz wave beam B detected by the detector 3 in S9 becomes high.

[0048] Terahertz waves have a longer wavelength than visible light and infrared light, and therefore tend to diffract easily. For this reason, the above-mentioned alignment method using diffraction is suitable for the terahertz beam B, and can achieve higher alignment accuracy. In addition, as shown in FIG. 4, in the broadband terahertz beam B, the lower frequency components tend to be distributed toward the outer periphery. For example, the low frequency components of "1-1.5 THz", which is the difference between the leftmost "1-3 THz" beam and the middle "1.5-3 THz" beam, are mainly distributed in the outermost circular region of the three regions of the leftmost "1-3 THz" beam. Here, since the low frequency components are long wavelength components, the long wavelength components that tend to diffract are present on the outer periphery of the terahertz beam B. For this reason, according to the method shown in FIG. 3, high-precision alignment can be achieved by utilizing the large diffraction of the long wavelength components on the outer periphery of the terahertz beam B.

[0049] In S10 in the measurement phase following the xy alignment phase (the first alignment phase and / or the second alignment phase), the aperture member 5 and the sample S are positioned relative to the terahertz wave beam B by the driver 6 in S4 and / or S9, and then the aperture controller 7 increases the size of the aperture 51 in the aperture member 5. This is to prevent the edge of the aperture 51 from interfering with the terahertz wave beam B measured in the following S11. Therefore, it is preferable that the size of the aperture 51 in S10 is as large as possible, for example, the aperture diameter is increased to a maximum value. Also, the size of the aperture 51 in S10 is set to the size of the terahertz wave beam B at the minimum. Since the aperture member 5 is not necessary in the measurement phase, the aperture member 5 may be removed from the aperture member holder 43 after the completion of the xy alignment phase.

[0050] In S11, the detection unit 3 detects the terahertz wave beam B in which the influence from the aperture 51, the size of which has been increased in S10, has been reduced.

[0051] In the present embodiment as described above, the aperture member 5 is driven integrally with the sample S in directions (xy directions) intersecting the traveling direction (z direction) of the terahertz wave beam B so that the intensity of the terahertz wave beam B detected by the detection unit 3 increases. Therefore, the sample S is appropriately positioned with respect to the terahertz wave beam B so that the terahertz wave beam B passing through the opening 51 in the aperture member 5 and detected by the detection unit 3 increases.

[0052] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0053] The configuration, action, and function of each device and method described in the embodiments can be realized by hardware resources or software resources, or by the cooperation of hardware resources and software resources. For example, a processor, ROM, RAM, and various integrated circuits can be used as hardware resources. For example, programs such as an operating system and applications can be used as software resources. [Explanation of symbols]

[0054] 1 measuring device, 2 irradiation unit, 3 detection unit, 5 aperture member, 6 drive unit, 7 aperture control unit, 41 xy stage, 51 aperture.

Claims

1. an irradiation unit that irradiates an electromagnetic wave beam onto a sample; a detection unit for detecting the electromagnetic beam from the sample; an aperture member provided between the irradiation unit and the detection unit and having an opening through which the electromagnetic wave beam can pass; a driving unit that drives the aperture member together with the sample in a direction intersecting a traveling direction of the electromagnetic wave beam so that an intensity of the electromagnetic wave beam detected by the detection unit is increased; A measuring device comprising:

2. The measurement device according to claim 1 , further comprising an aperture control unit that controls a substantial size of the aperture relative to the electromagnetic wave beam.

3. The measurement device according to claim 2 , wherein the aperture control unit controls a diameter of the aperture.

4. The opening control unit reduces a size of the opening after the first driving of the opening member by the driving unit, The drive unit performs a second drive of the opening member after the size of the opening is reduced by the opening control unit.

3. The measuring device according to claim 2.

5. the aperture control unit sets a size of the aperture larger than a size of the electromagnetic wave beam, When the opening member is driven by the driving unit, at least a part of the electromagnetic wave beam diffracted by the opening is not irradiated to the detection unit.

3. The measuring device according to claim 2.

6. In a first positioning process of the aperture member and the sample with respect to the electromagnetic wave beam by the driving unit, The opening control unit reduces a size of the opening after the first driving of the opening member by the driving unit, the drive unit performs a second drive of the opening member after the size of the opening is reduced by the opening control unit, a second positioning process of the aperture member and the sample relative to the electromagnetic wave beam by the driving unit, the second positioning process being executed after the first positioning process, the aperture control unit sets a size of the aperture larger than a size of the electromagnetic wave beam, When the opening member is driven by the driving unit, at least a part of the electromagnetic wave beam diffracted by the opening is not irradiated to the detection unit.

3. The measuring device according to claim 2.

7. 7. The measurement device of claim 2, wherein after the aperture member and the sample are positioned relative to the electromagnetic beam by the driving unit, the aperture control unit increases the size of the aperture, and the detection unit detects the electromagnetic beam with reduced influence from the aperture.

8. The measurement device according to claim 1 , wherein the aperture member is provided between the irradiation unit and the sample.

9. The measuring device according to claim 1 , wherein the electromagnetic wave is a terahertz wave.

10. Irradiating the sample with an electromagnetic wave beam by an irradiation unit; detecting the electromagnetic beam from the sample by a detection unit; a driving unit that drives an aperture member that is provided between the irradiation unit and the detection unit and has an opening through which the electromagnetic wave beam can pass, and drives the aperture member together with the sample in a direction intersecting a traveling direction of the electromagnetic wave beam so that an intensity of the electromagnetic wave beam detected by the detection unit becomes high; How to perform the measurement.

11. Irradiating the sample with an electromagnetic wave beam by an irradiation unit; detecting the electromagnetic beam from the sample by a detection unit; a driving unit that drives an aperture member that is provided between the irradiation unit and the detection unit and has an opening through which the electromagnetic wave beam can pass, and drives the aperture member together with the sample in a direction intersecting a traveling direction of the electromagnetic wave beam so that an intensity of the electromagnetic wave beam detected by the detection unit becomes high; A measurement program that causes a computer to execute the above.

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