WO2018154690A1 - Dispositif de mesure térahertz, dispositif d'inspection, procédé de mesure térahertz et procédé d'inspection - Google Patents

Dispositif de mesure térahertz, dispositif d'inspection, procédé de mesure térahertz et procédé d'inspection Download PDF

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Publication number
WO2018154690A1
WO2018154690A1 PCT/JP2017/006930 JP2017006930W WO2018154690A1 WO 2018154690 A1 WO2018154690 A1 WO 2018154690A1 JP 2017006930 W JP2017006930 W JP 2017006930W WO 2018154690 A1 WO2018154690 A1 WO 2018154690A1
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terahertz
light
optical path
receiver
transmitter
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PCT/JP2017/006930
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English (en)
Japanese (ja)
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康弘 日高
田中　稔久
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株式会社ニコン
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Priority to PCT/JP2017/006930 priority Critical patent/WO2018154690A1/fr
Publication of WO2018154690A1 publication Critical patent/WO2018154690A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
    • G01N21/3586—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation by Terahertz time domain spectroscopy [THz-TDS]

Definitions

  • the present invention relates to a terahertz measurement device, an inspection device, a terahertz measurement method, and an inspection method.
  • a laser from a femtosecond laser is divided into a pump light and a probe light, and the terahertz wave generating element is irradiated with the pump light, while the probe light is branched into four by a beam splitter, each via a time delay stage.
  • a physical property measuring apparatus that performs time-division processing for synthesizing terahertz waveforms by irradiating a plurality of terahertz wave detection elements (for example, Patent Document 1).
  • Patent Document 1 a physical property measuring apparatus that performs time-division processing for synthesizing terahertz waveforms by irradiating a plurality of terahertz wave detection elements
  • the terahertz measuring device receives a terahertz transmitter that transmits terahertz light toward the object to be measured by receiving pulsed light, and a terahertz reception that receives the terahertz light from the object to be measured. And a terahertz light arrival time changing element that changes the time at which the terahertz light emitted from the terahertz transmitter reaches the terahertz receiver with respect to the time when the pulsed light is generated.
  • the terahertz light arrival time changing element is arranged on an optical path from the terahertz transmitter to the terahertz receiver, and the terahertz transmitter to the terahertz In the path through which the terahertz light propagates up to the receiver, it is preferable to change the optical path length for each path that passes through different positions of the object to be measured.
  • the terahertz light arrival time changing element includes at least a part of the light flux of the terahertz light emitted from the terahertz transmitter and another light flux.
  • the terahertz light arrival time changing element includes a converging optical system that converges the terahertz light from the terahertz transmitter. It is preferable that the optical system is disposed in the vicinity of the converging optical system.
  • the pulsed light source device that generates the pulsed light and the pulsed light generated by the pulsed light source device are each the terahertz transmitter.
  • a pulsed light delay time changing unit that changes a delay time for delaying the time to be transmitted, the terahertz transmitter transmits the terahertz light at a timing when the pulsed light is incident, and the terahertz receiver includes the terahertz receiver, The terahertz light is received at a timing when pulsed light is incident, and the pulsed light delay time changing unit is configured to transmit the pulse light.
  • the delay time is changed by changing the optical path length of the path through which the pulse light propagates from the light source device to the terahertz receiver, and the terahertz light arrival time changing element can be changed by the pulse light delay time changing unit It is preferable to change the arrival time of the terahertz light to the terahertz receiver within a range of a long delay time.
  • the irradiation is performed such that the position of the irradiation region irradiated with the terahertz light is changed relative to the object to be measured.
  • a position changing unit wherein the irradiation position changing unit changes a positional relationship between the irradiation region and the object to be measured in synchronization with a change in time when the terahertz light reaches the terahertz receiver; Is preferred.
  • the irradiation position changing unit synchronizes with the change in the optical path length by the pulse light delay time changing unit, It is preferable to change the position of the irradiation region irradiated with the terahertz light with respect to the object to be measured.
  • the pulsed light delay time changing unit is configured such that the pulsed light is incident on the terahertz transmitter within a period for acquiring the time waveform information of the terahertz light.
  • a plurality of times for detecting the amplitude of the terahertz light by the terahertz receiver with respect to the time to be transmitted, and the irradiation position changing unit is configured to acquire at least one of the irradiation regions within a period for acquiring the time waveform information of the terahertz light.
  • the positional relationship between the irradiation region and the object to be measured is changed so that the portion is irradiated with the terahertz light at different positions on the object to be measured.
  • at least a part of the light beam of the terahertz light and the other part, in which different optical path lengths are set by the terahertz light arrival time changing element It is preferable to further include an optical system for irradiating different positions of the object to be measured.
  • the terahertz light arrival time changing element acquires time waveform information of the terahertz light, so that the pulsed light is transmitted to the terahertz transmitter. It is preferable that the optical path length given to the terahertz light is sequentially switched within a period in which the time for detecting the amplitude of the terahertz light by the terahertz receiver with respect to the incident time is set.
  • the irradiation position changing unit is configured by a galvano mirror, and the terahertz light transmitted from the terahertz transmitter and reflected by the irradiation position changing unit is
  • the terahertz transmitter further comprising an objective optical system that condenses the terahertz light reflected on the object to be measured and is reflected by the object to be measured and reflected on the terahertz receiver by being reflected by the irradiation position changing unit.
  • the terahertz receiver are preferably arranged at positions decentered with respect to the optical path of the terahertz light propagating through the objective optical system.
  • the terahertz light transmitted from the terahertz transmitter and whose irradiation direction is changed by the irradiation position changing unit is condensed on the object to be measured, and
  • the terahertz measurement device receives the terahertz transmitter that transmits the terahertz light toward the object to be measured by receiving the pulse light, and the terahertz reception that receives the terahertz light from the object to be measured. And a terahertz receiver for obtaining time waveform information of the terahertz light, and disposed on an optical path of the pulsed light from the pulse light source device that emits the pulsed light to the terahertz transmitter.
  • the inspection device includes the terahertz measurement device according to any one of the first to thirteenth aspects and the detection result of the terahertz light from each position on the measurement object. And an inspection unit for inspecting foreign matters or defects on the measurement object.
  • the terahertz measurement method when pulsed light is supplied, the terahertz light is transmitted from the terahertz transmitter to the object to be measured, and the terahertz light from the object to be measured is received by the terahertz. And the time at which the terahertz light emitted from the terahertz transmitter reaches the terahertz receiver is changed with respect to the time when the pulsed light is generated by the terahertz light arrival time changing element.
  • the terahertz transmitter reaches the terahertz light by the terahertz light arrival time changing element disposed on the optical path from the terahertz transmitter to the terahertz receiver.
  • the optical path length In the path through which the terahertz light propagates up to the receiver, it is preferable to change the optical path length for each path that passes through different positions of the object to be measured.
  • at least part of the light flux of the terahertz light emitted from the terahertz transmitter by the terahertz light arrival time changing element is changed to another light flux.
  • the terahertz light disposed in the vicinity of the exit side of a converging optical system that converges the terahertz light from the terahertz transmitter. It is preferable to change the time by an arrival time changing element.
  • the pulsed light source device generates the pulsed light, and the pump optical system and the probe optical system provide the pulsed light source device.
  • the pulse light delay time changing unit disposed in the probe optical system causes the pulsed light to enter the terahertz transmitter.
  • the terahertz transmitter transmits the terahertz light at a timing when the pulsed light is incident
  • the terahertz receiver receives the terahertz light at a timing when the pulsed light is incident;
  • the pulse light delay time changing unit changes the delay time by changing the optical path length of the path through which the pulse light propagates from the pulse light source device to the terahertz receiver, and the terahertz light arrival time changing element
  • the arrival time of the terahertz light at the terahertz receiver is changed within a delay time range that can be changed by the pulse light delay time changing unit.
  • the position of the irradiation region irradiated with the terahertz light by the irradiation position changing unit is set with respect to the object to be measured.
  • the irradiation position changing unit further synchronizes with the change in the time when the terahertz light reaches the terahertz receiver, and the positional relationship between the irradiation region and the object to be measured is provided. It is preferable to change.
  • the irradiation position changing unit causes the terahertz light to synchronize with the change in the optical path length by the pulse light delay time changing unit. It is preferable to change the position of the irradiation area irradiated with the measurement object.
  • the pulsed light is incident on the terahertz transmitter within a period in which the pulse light delay time changing unit acquires time waveform information of the terahertz light.
  • the terahertz measurement method in the terahertz measurement method according to the twenty-second aspect, at least a part of the light beam of the terahertz light and another part, in which different optical path lengths are set by the optical system by the terahertz light arrival time changing element It is preferable to irradiate different positions of the object to be measured.
  • the terahertz light arrival time changing element since the terahertz light arrival time changing element acquires time waveform information of the terahertz light, the pulsed light is transmitted to the terahertz transmitter.
  • the optical path length given to the terahertz light is sequentially switched within a period in which the time for detecting the amplitude of the terahertz light by the terahertz receiver with respect to the incident time is set.
  • the irradiation position changing unit is configured by a galvanometer mirror, and is transmitted from the terahertz transmitter and reflected by the irradiation position changing unit by an objective optical system.
  • the terahertz light collected on the object to be measured, and the terahertz light reflected on the object to be measured is reflected by the irradiation position changing unit and condensed on the terahertz receiver.
  • the terahertz transmitter and the terahertz receiver are preferably arranged at positions decentered with respect to the objective optical system.
  • the objective optical system condenses the terahertz light transmitted from the terahertz transmitter and reflected by the irradiation position changing unit on the object to be measured.
  • the terahertz light reflected by the object to be measured is further reflected by the irradiation position changing unit and condensed on the terahertz receiver, and the irradiation position changing unit is a focal position of the objective optical system And an optical path that reaches the terahertz receiver from one of the plurality of reflection surfaces, and the terahertz from the other reflection surface. It is preferable that the terahertz light arrival time changing element is arranged so that an optical path length difference is generated between the optical path reaching the receiver.
  • pulsed light is supplied to transmit terahertz light from the terahertz transmitter toward the object to be measured, and terahertz light from the object to be measured is received by terahertz.
  • the time waveform information of the terahertz light is received by a terahertz light arrival time changing element disposed on the optical path of the pulsed light from the pulse light source device that emits the pulsed light to the terahertz transmitter.
  • an optical path length to be given to the pulsed light from the pulsed light source device to the terahertz transmitter is set within a period in which the time for detecting the amplitude of the terahertz light is set by the terahertz receiver. Sequentially switching to the optical path.
  • the inspection method is based on the terahertz measurement method according to any one of the fifteenth to twenty-seventh aspects and the detection result of the terahertz light from each position on the measurement object. And inspecting foreign matter or defects on the object to be measured.
  • FIG. 1 is a schematic diagram showing a main configuration of a terahertz measuring apparatus 100 according to the present embodiment.
  • the terahertz measurement apparatus 100 according to the present embodiment performs measurement by terahertz time domain spectroscopy (TDS). That is, the terahertz measurement apparatus 100 irradiates the measurement object S with terahertz pulse light, and detects a time change in the electric field amplitude of the terahertz pulse light transmitted through the measurement object S.
  • TDS terahertz time domain spectroscopy
  • the terahertz measurement device 100 generates a time waveform of terahertz pulse light based on the detected signal, and acquires amplitude information at each frequency by performing Fourier transform on the waveform.
  • various substances such as solid and liquid are provided.
  • the terahertz measurement device 100 mainly includes a laser light source 1, a measurement optical unit 51, an optical delay unit 10, a control device 20, and a scanning unit 40.
  • the measurement optical unit 51 includes an optical path length conversion unit 30, a first condensing optical system 61, a second condensing optical system 62, a first lens group 71, a second lens group 72, a transmitter 50, And a receiver 80.
  • the transmitter 50 generates terahertz pulse light that irradiates the measurement object S, and the terahertz pulse light that has passed through the measurement object S enters the receiver 80.
  • the transmitter 50 includes, for example, an optical switch element and a bias circuit.
  • the transmitter 50 is irradiated with the laser pulse light from the laser light source 1 as the pump pulse light through the optical path L2.
  • the receiver 80 includes, for example, an optical switch element and an IV conversion circuit.
  • the receiver 80 is irradiated with the laser pulse light from the laser light source 1 as the probe pulse light through the optical path L3.
  • the laser light source 1 generates laser pulse light in the near-infrared wavelength region having a pulse time width of several tens of femtoseconds, for example, and the repetition frequency of the generation is several hundreds of MHz, for example.
  • the laser pulse light output from the laser light source 1 propagates through the optical path L1, is branched by the beam splitter 2, and becomes the above-described pump pulse light and probe pulse light, respectively.
  • the pump pulse light that passes through the beam splitter 2 and propagates through the optical path L ⁇ b> 2 is reflected by the mirror 5 and enters the transmitter 50.
  • the terahertz pulse light is emitted from the transmitter 50 and propagates through the optical path L4.
  • the pulse width of the terahertz pulse light is very short, for example, 1 picosecond or less.
  • the terahertz pulse light propagated through the optical path L4 is collimated by the first condensing optical system 61, then passes through the optical path length conversion unit 30, is condensed by the first lens group 71, and irradiates the object S to be measured. Details of the optical path length conversion unit 30 will be described later.
  • the scanning unit 40 includes a scanning mechanism including a driving unit such as a motor, and is controlled by the control device 20 to be described later.
  • the scanning unit 40 moves the object to be measured S two-dimensionally on a plane intersecting the propagation direction of the terahertz pulse light, The relative positional relationship between the object S and the measurement optical unit 51 is changed.
  • the irradiation region where the terahertz pulse light irradiates the measurement object S is two-dimensionally scanned on the measurement object S.
  • the scanning unit 40 functions as an irradiation position changing unit that changes the position of the irradiation region irradiated with the terahertz pulse light relative to the measurement object S.
  • the scanning unit 40 may move the measurement optical unit 51 two-dimensionally along a plane that intersects the propagation direction of the terahertz pulse light while the position of the object S to be measured is fixed.
  • the scanning unit 40 may have a configuration in which the positional relationship between the measurement object S and the measurement optical unit 51 can be changed three-dimensionally. Further, as the scanning unit 40, the terahertz pulse light irradiates the object S to be measured with a drivable optical element that changes the propagation direction of the terahertz pulse light propagating through the optical path L 4, for example, a movable mirror such as a galvanometer mirror. The irradiation area may be configured to be two-dimensionally scanned. Further, the scanning unit 40 may combine the movement of the measurement object S, the movement of the measurement optical unit 51, and the change of the propagation direction of the terahertz pulse light depending on the size of the scanning range of the measurement object S. The terahertz pulse light transmitted through the device under test S propagates through the optical path L5, passes through the second lens group 72 and the second condensing optical system 62, and enters the receiver 80.
  • the probe pulse light branched by the beam splitter 2 propagates through the optical path L31, is reflected by the mirror 3, and reaches the optical delay unit 10.
  • a movable folding mirror 11 is mounted on the delay stage 12 of the optical delay unit 10, and the reached probe pulse light is folded by the folding mirror 11 and reflected by the mirror 4 to irradiate the optical switch element of the receiver 80.
  • the folding mirror 11 is moved on the delay stage 12 in the direction of the arrow Ar1 in the optical axis direction of the optical path L32 by a driving device such as a motor.
  • the position of the folding mirror 11 is precisely measured by a linear movement detector such as a linear encoder.
  • the movement of the folding mirror 11 is controlled by a delay time control unit 201 of the control device 20 described later.
  • the optical path length of the optical path L32 changes as the folding mirror 11 moves on the delay stage 12.
  • the timing at which the pump pulse light irradiates the transmitter 50 and the timing at which the probe pulse light irradiates the receiver 80 can be adjusted. That is, the timing at which the transmitter 50 emits terahertz pulse light and the timing at which the receiver 80 detects terahertz light can be adjusted. Thereby, the timing at which the receiver 80 detects the amplitude of the terahertz pulse light emitted from the transmitter 50 at a constant interval of the pulse interval T can be shifted each time the terahertz pulse light is emitted.
  • the delay time control unit 201 causes the folding mirror 11 of the optical delay unit 10 to shift the detection timing by the receiver 80 every time the terahertz pulse light is emitted. Control is performed so that the probe light reaches the receiver 80 at an appropriate timing. Thereby, the entire time waveform (time amplitude waveform) representing the amplitude of one terahertz pulse light can be obtained by detecting the terahertz pulse light a plurality of times and combining the detection results.
  • the electric field amplitude at each detection timing of the terahertz pulse light detected by the receiver 80 is sequentially output to the control device 20 as a voltage signal, and is converted into a voltage signal by the IV conversion circuit.
  • a time-series waveform (time amplitude waveform) E (t) of the electric field amplitude of the terahertz pulse light is obtained.
  • the voltage signal is converted into a digital signal by a measurement data generation unit 202 of the control device 20 described later.
  • the control device 20 includes a microprocessor, peripheral circuits, and the like.
  • the control device 20 reads and executes a control program stored in advance in a storage medium (not shown) (for example, a flash memory), thereby executing the control of the terahertz measurement device 100. Control each part.
  • the control device 20 includes a delay time control unit 201, a measurement data generation unit 202, a scanning control unit 203, and an inspection unit 210.
  • the delay time control unit 201 controls the movement of the folding mirror 11 in order to control the delay time in the optical delay unit 10.
  • the optical delay unit 10 synthesizes a time amplitude waveform, which will be described later, based on the amplitude information of the terahertz light received by the receiver 80, so that the probe pulse light with respect to the timing at which the pump pulse light irradiates the transmitter 50 is It functions as a pulsed light delay time changing unit that changes the delay time that is the timing of irradiation of the receiver 80.
  • the position of the folding mirror 11 is detected by, for example, a linear encoder or the like and input to the delay time control unit 201 and the measurement data generation unit 202.
  • the measurement data generation unit 202 generates a terahertz time amplitude waveform E (t) using the voltage signal (detection voltage) output from the receiver 80 and the delay time based on the position of the folding mirror 11.
  • the terahertz time amplitude waveform E (t) is displayed on a display device (not shown), for example.
  • the scanning control unit 203 controls the scanning unit 40 to change the relative positional relationship between the irradiation position of the terahertz pulse light on the measured object S and the measured object S.
  • the scanning unit 40 includes a galvanometer mirror
  • the scanning control unit 203 controls the driving of the reflection surface of the galvanometer mirror, thereby changing the position of the irradiation region where the terahertz pulse light irradiates the object S to be measured.
  • the inspection unit 210 inspects the foreign object and the defect of the measurement object S based on the terahertz time amplitude waveform E (t) generated by the measurement data generation unit 202.
  • the optical path length conversion unit 30 is formed of, for example, a fluororesin, and is disposed on the optical path L4 between the transmitter 50 and the receiver 80, and generates a plurality of different optical path lengths.
  • the optical path length conversion unit 30 will be described by taking an example in which three different optical path lengths are set. However, the number of different optical path lengths to be set is not limited to this and may be two. And four or more may be sufficient.
  • the optical path length conversion unit 30 is disposed in the optical path L4 between the first condensing optical system and the measurement object S.
  • the optical path length conversion unit 30 includes a first region 311, a second region 312, and a third region 313.
  • the thickness of each region 311 to 313 is along the propagation direction of the terahertz pulse light propagating through the optical path L4. Different from each other. In the example illustrated in FIG. 1, a case where the thickness increases in the order of the first region 311, the second region 312, and the third region 313 is illustrated. That is, the terahertz pulse light transmitted through the first region 311, the second region 312, and the third region 313 forms a plurality of optical paths L41, L42, and L43 having different optical path lengths.
  • the propagation speed of the terahertz pulse light transmitted through the optical paths L41, L42, and L43 having different optical path lengths varies depending on the optical path lengths of the optical paths L41, L42, and L43. For this reason, a deviation occurs in the timing at which the terahertz pulse light reaches the device under test S.
  • the optical path length conversion unit 30 functions as a terahertz light arrival time changing element that changes the timing at which the terahertz pulse light reaches the receiver 80.
  • the terahertz pulse light is temporally separated by being divided into optical paths L41, L42, and L43 having different optical path lengths and propagating.
  • the first lens group 71 is provided between the optical path length conversion unit 30 and the object S to be measured (the emission side of the optical path length conversion unit 30), and includes a first region 311, a second region 312, and the optical path length conversion unit 30.
  • a 1-1 lens unit 711, a 1-2 lens unit 712, and a 1-3 lens unit 713 are provided at positions corresponding to the third region 313, respectively.
  • the terahertz pulse light propagated through the optical path L41 corresponding to the first region 311 of the optical path length conversion unit 30 is condensed by the 1-1 lens unit 711 and irradiates the position P1 of the object S to be measured.
  • the terahertz pulse light propagated through the optical path L42 corresponding to the second region 312 of the optical path length conversion unit 30 is condensed by the first-second lens unit 712 and irradiates the position P2 of the object S to be measured.
  • the terahertz pulse light that has propagated through the optical path L43 corresponding to the third region 313 of the optical path length conversion unit 30 is condensed by the 1-3 lens unit 713 and irradiates the position P3 of the object S to be measured. That is, the terahertz pulse light propagating through the optical paths L41, L42, and L43 is temporally separated and reaches and passes through three different positions P1, P2, and P3 of the DUT S at different timings.
  • the terahertz pulse light transmitted through three different positions P1, P2, and P3 of the object S to be measured propagates through the optical paths L51, L52, and L53, respectively, and is received through the second lens group 72 and the second condensing optical system 62.
  • the second lens group 72 includes a 2-1 lens unit 721, a 2-2 lens unit 722, and a 2-3 lens unit 723.
  • the 2-1 lens portion 721 corresponds to the 1-1 lens portion 711
  • the 2-2 lens portion 722 corresponds to the 1-2 lens portion 712
  • the 2-3 lens portion 723 corresponds to the 1-3. They are arranged at positions corresponding to the lens portions 713, respectively.
  • the terahertz pulse light that has passed through the position P1 of the object to be measured S and propagated through the optical path L51 is condensed by the second condensing optical system 62 through the 2-1 lens unit 721 and enters the receiver 80.
  • the terahertz pulse light transmitted through the position P ⁇ b> 2 of the object to be measured S and propagated through the optical path L ⁇ b> 52 is condensed by the second condensing optical system 62 through the 2-2 lens unit 722 and enters the receiver 80.
  • the terahertz pulse light that has passed through the position P3 of the object to be measured S and propagated through the optical path L53 is condensed by the second condensing optical system 62 via the 2-3 lens unit 723 and is incident on the receiver 80.
  • corresponding terahertz pulse lights respectively transmitted through three different positions P1, P2, and P3 of the object to be measured S are sequentially incident on the receiver 80 at different timings.
  • the terahertz pulse light propagated through the optical path L51 reaches the receiver 80 earliest, then the terahertz pulse light propagated through the optical path L52 reaches the receiver 80, and then propagates through the optical path L53.
  • the terahertz pulse light reaches the receiver 80.
  • FIG. 2A and 2B schematically show the time amplitude waveform E (t) of the terahertz pulse light incident on the receiver 80.
  • FIG. FIG. 2A shows each time amplitude waveform E (t) of the terahertz pulse light sequentially incident on the receiver 80 at the pulse interval T.
  • FIG. FIG. 2B shows a time amplitude waveform E (t) of the terahertz pulse light obtained by combining by the control device 20 based on the detection result by the receiver 80.
  • the generation of the time amplitude waveform E (t) of the terahertz pulse light by the control device 20 will be described later.
  • the terahertz pulse light propagating in the optical path L4 is temporally separated into three terahertz pulse lights, and each transmits through different positions P1, P2, and P3 of the measurement object S at different timings.
  • These terahertz pulse lights sequentially enter the receiver 80 at different timings. Therefore, by emitting the pump pulse light once to the transmitter 50 and emitting the terahertz pulse light once, the receiver 80 has a plurality of terahertz pulses transmitted through the positions P1, P2, and P3 of the object S to be measured. Light enters sequentially.
  • each of the positions P1, P2, and P3 of the object S to be measured is obtained. There are three corresponding peaks Pu1, Pu2, Pu3.
  • the time intervals between the peaks Pu1, Pu2, and Pu3 depend on the thickness of the first region 311, the thickness of the second region 312 and the thickness of the third region 313 of the optical path length conversion unit 30. Therefore, the difference in thickness between the first region 311, the second region 312, and the third region 313 of the optical path length conversion unit 30 is that the detection time of each of the peaks Pu1, Pu2, and Pu3 is equal to the pulse interval T of the terahertz pulse light. Determined to fit.
  • the pulse interval T is, for example, 80 [ps].
  • the terahertz pulse light having the three peaks Pu1, Pu2, and Pu3 corresponding to the positions P1, P2, and P3 of the object to be measured S is incident on the receiver 80 within the pulse interval T.
  • the delay time control unit 201 operates the optical delay unit 10 so that the difference in timing at which the probe pulse light irradiates the receiver 80 is gradually increased with respect to the timing at which the pump pulse light irradiates the transmitter 50. Control.
  • a predetermined number of times (for example, 800 times) of terahertz pulse light while changing the time for detecting the amplitude of the terahertz pulse light received by the receiver 80 with respect to the emission time of the terahertz pulse light from the transmitter 50. Is emitted from the transmitter 50, and the terahertz pulse light transmitted through the object S to be measured is incident on the receiver 80.
  • the delay time control unit 201 moves the folding mirror 11 of the optical delay unit 10 on the delay stage 12 by an appropriate distance along the propagation path of the probe pulse light.
  • the receiver 80 detects the amplitude of the sampling position Po2. This situation is shown in the second graph from the left in FIG. The voltage signal corresponding to the detected amplitude is also output to the control device 20 as described above.
  • sampling positions Po3,... Pon of the time amplitude waveform E (T) of the terahertz pulse light at time t3,. are detected, and a voltage signal corresponding to these amplitudes is output to the control device 20.
  • the voltage signals corresponding to the amplitudes at the sampling positions Po1, Po2, Po3,... Pon output to the control device 20 are synthesized by the measurement data generation unit 202, and the terahertz pulse light as shown in FIG.
  • a time amplitude waveform E (t) is generated. In this way, the time amplitude waveform E (t) of the terahertz pulse light transmitted through the three different positions P1, P2, and P3 of the object to be measured S is obtained.
  • the inspection unit 210 peaks the time amplitude waveform E (t) of the terahertz pulse light transmitted through the three different positions P1, P2, and P3 of the measurement object S generated by the measurement data generation unit 202 in the time amplitude waveform.
  • the timing at which the waveform appears, the shape of the time amplitude waveform, the distribution and size values of the frequency components constituting the time amplitude waveform, and the like are obtained, and based on these, the presence or absence of a defect or a foreign object is measured. Further, relative position information of three positions P1, P2, and P3 may be considered.
  • the scanning unit 40 applies the terahertz pulse to the object to be measured. Change the position where light is irradiated. That is, when sampling from t1 to tn is completed for the terahertz pulse light, the delay time control unit 201 returns the folding mirror 11 of the optical delay unit 10 to the initial position, and the scanning unit 40 determines the irradiation target position of the object S to be measured. change.
  • the amount of change when changing the irradiation target position by the scanning unit 40 may be set so that the irradiation area of the measurement object S by the terahertz pulse light is completely different before and after the change, It may be set to irradiate a partially overlapping region.
  • the terahertz measurement apparatus 100 measures the terahertz pulse light after being transmitted through the measurement object discretely in the measurement object range of the measurement object S by repeating the same process as described above.
  • step S1 the terahertz pulse light is emitted from the transmitter 50 toward the object S to be measured, and the process proceeds to step S2.
  • step S2 the terahertz pulse light propagating through the optical paths having different optical path lengths generated by the optical path length converting unit 30 is transmitted at different positions P1, P2, and P3 of the object S to be measured and then incident on the receiver 80. Then, the process proceeds to step S3.
  • step S3 the measurement data generation unit 202 generates a time amplitude waveform E (t) of the terahertz pulse light and proceeds to step S4.
  • step S4 it is determined whether or not the generation of the time amplitude waveform E (t) of the terahertz pulse light corresponding to all the measurement target positions of the DUT S has been completed.
  • step S6 the inspection unit 210 inspects the foreign object or defect of the measurement object S and ends the process. If there is a measurement target position that has not been processed, a negative determination is made in step S4, and the process proceeds to step S5.
  • step S5 the control device 20 controls the scanning unit 40 to change the irradiation region so that the terahertz pulse light irradiates another measurement target position of the object S to be measured, and returns to step S1.
  • the terahertz measurement apparatus 100 includes an optical path length conversion unit 30 that changes the time at which at least a part of the terahertz pulse light emitted from the transmitter 50 reaches the receiver 80.
  • an optical path length conversion unit 30 that changes the time at which at least a part of the terahertz pulse light emitted from the transmitter 50 reaches the receiver 80.
  • the optical path length conversion unit 30 changes the optical path lengths of the optical paths L41, L42, and L43 for each path that passes through different positions P1, P2, and P3 of the DUT. Thereby, the terahertz pulse light emitted once from the transmitter 50 is irradiated to a plurality of measurement target positions of the measurement object S, which contributes to shortening the measurement time of the measurement object S.
  • the optical path length conversion unit 30 imparts an optical path length different from other light beams to at least a part of the light beams of the terahertz pulse light emitted from the transmitter 50.
  • the terahertz pulse light which irradiates the several measurement object position from which the to-be-measured object S differs from one terahertz pulse light can be produced
  • the terahertz pulse light emitted from the transmitter 50 is converged (collimated) by the first condensing optical system 61 and then transmitted through the optical path length conversion unit 30.
  • the temporal separation of the terahertz pulse light propagating in the optical paths L41, L42, and L43 can be favorably performed.
  • the terahertz pulse light propagating through the optical paths L41, L42, and L43 can be temporally separated from a single outgoing terahertz pulse light from the transmitter 50. Thereby, the measurement object S can be measured in a short time.
  • the scanning unit 40 acquires the entire time amplitude waveform E (t) of the set of terahertz pulse light that propagates through the optical paths L51, L52, and L53 and enters the receiver 80, and then The irradiation area of the terahertz pulse light is changed. Thereby, the terahertz pulse light can be made to reach a new position of the measurement object S, and the measurement target position of the measurement object S can be measured without omission.
  • the first lens group 71 transmits the terahertz pulse light propagating through each of the optical paths L41, L42, and L43 set with different optical path lengths by the optical path length conversion unit 30 to different positions P1, P2, and Irradiate P3.
  • the optical path length conversion unit 30 As a result, as shown in FIG. 2B, it is possible to generate a time amplitude waveform E (t) of the terahertz pulse light transmitted through different positions P1, P2, and P3 on the measurement object S.
  • FIG. 12A shows a time amplitude waveform E (t) in which the terahertz pulse light from the transmitter 50 is incident on the receiver 80 at the pulse interval T.
  • the receiver 80 detects the amplitude of the plurality of terahertz pulse lights incident at the pulse interval T while sequentially shifting the sampling position, and outputs a voltage signal corresponding to the amplitude to the control device 20. Since the amplitude detected here corresponds to the time amplitude waveform E (t) corresponding to one position of the device under test S, the sampling positions Po1, Po2, Po3, tn at times t1, t2,. ... The time amplitude waveform E (t) obtained by synthesizing the detected amplitude of Pon is also only related to one position of the object S to be measured.
  • FIG. 12B shows a time amplitude waveform E (t) of the terahertz pulse light generated by the control device 20. In this case, it is not possible to measure a plurality of measurement positions of the object S to be measured by one emission of the terahertz pulse light from the transmitter 50.
  • FIG. 4 is a diagram schematically showing the measurement optical unit 51 in the second embodiment.
  • FIG. 4 is a simplified schematic diagram mainly showing a measurement optical unit in which the measurement optical unit 51 is partially changed in the terahertz measurement apparatus 100 according to the first embodiment shown in FIG.
  • the measurement optical unit 51 in the second embodiment can apply the same configuration as the configuration of the first embodiment with respect to the configuration other than the measurement optical unit 51.
  • the optical path length conversion unit 30 is provided in the optical path between the first condensing optical system 61 and the second condensing optical system.
  • the object to be measured S is provided in the optical path between the second condensing optical system 62 and the third condensing optical system 63. Note that the terahertz measurement apparatus 100 according to the present embodiment does not include the first lens group 71 and the second lens group 72.
  • the optical path length conversion unit 30 sets three different optical path lengths will be described as an example.
  • the number of different optical path lengths to be set is It is not limited to this, 2 may be sufficient and 4 or more may be sufficient.
  • the terahertz pulse light emitted from the transmitter 50 propagates through the optical path L 4, is deflected in the propagation direction by the galvanometer mirror 44, and then enters the first condensing optical system 61.
  • the terahertz pulse light collimated by the first condensing optical system 61 enters the optical path length conversion unit 30.
  • the optical path length conversion unit 30 includes the first region 311, the second region 312, and the third region 313.
  • the regions 311 to 313 have different lengths along the propagation direction of the terahertz pulse light. (Thickness).
  • the terahertz pulse light that transmits the first region 311 and propagates the optical path L41 the terahertz pulse light that transmits the second region 312 and propagates the optical path L42, and the third region
  • the terahertz pulse light that transmits the second region 312 and propagates the optical path L42 the third region
  • the thickness increases in the order of the first region 311, the second region 312, and the third region 313.
  • the terahertz pulse light propagating through the optical path L4 reaches the object to be measured S earliest, then the terahertz pulse light propagated through the optical path L42 reaches the object to be measured S, and then the terahertz pulse propagated through the optical path L43 The light reaches the object S to be measured.
  • the scanning control unit 203 controls the scanning unit 40 to change the position where the object to be measured S is irradiated with the terahertz pulse light. That is, the scanning unit 40 changes the direction of the reflection surface of the galvanometer mirror 44 to change the angle of the optical path through which the terahertz pulse light propagates. Specifically, it is as follows. The scanning unit 40 sets the direction of the reflecting surface of the galvanometer mirror 44 to the initial position. In this state, the position at which the terahertz light propagating through the optical path L41 irradiates the measurement object S is P1.
  • the scanning unit 40 After the terahertz pulse light propagating in the optical path L41 passes through the position P1 of the object to be measured S, the scanning unit 40 is configured so that the terahertz pulse light propagating in the optical path L42 reaches the position P2 of the object to be measured S. Change the direction of the reflective surface. After the terahertz pulse light propagating in the optical path L42 passes through the position P2 of the object to be measured S, the scanning unit 40 is configured so that the terahertz pulse light propagating in the optical path L43 reaches the position P3 of the object to be measured S. Change the direction of the reflective surface.
  • the scanning unit 40 After the terahertz pulse light propagating through the optical path L43 passes through the position P3 of the object S to be measured, the scanning unit 40 returns the direction of the reflecting surface of the galvanometer mirror 44 to the initial position. Further, the scanning unit 40 moves the measurement object S in the direction of the arrow Ar2 so that the terahertz pulse light propagating through the optical path L41 reaches the new measurement position of the measurement object S. That is, the change in the direction of the reflection surface of the galvanometer mirror 44 by the scanning unit 40 is performed in synchronization with the change in the time for the terahertz pulse light to reach the object S to be measured. Thereafter, the above operation is repeated.
  • Terahertz pulse light transmitted through three different positions P1, P2, and P3 of the object to be measured S propagates through the optical paths L51, L52, and L53, respectively, and sequentially enters the receiver 80.
  • the time amplitude waveform E (t) of the terahertz pulse light incident on the receiver 80 is similar to the case of the first embodiment shown in FIG. , P3 has three peaks Pu1, Pu2, Pu3.
  • the delay time control unit 201 performs the timing at which the probe pulse light irradiates the receiver 80 with respect to the timing at which the pump pulse light irradiates the receiver 80.
  • the operation of the optical delay unit 10 is controlled so that the difference between the two increases little by little.
  • a predetermined number of times (for example, 800 times) of terahertz pulse light is emitted from the transmitter 50, and the terahertz pulse light that has passed through the measurement object S is incident on the receiver 80.
  • the detection of the terahertz pulse light by the receiver 80 and the generation of the time amplitude waveform E (t) of the terahertz pulse light are also performed as in the first embodiment. That is, based on the voltage signal corresponding to the amplitude at the sampling positions Po1, Po2, Po3,... Pon sequentially output from the receiver 80 to the control device 20, the measurement data generating unit 202 is as shown in FIG. A time amplitude waveform E (t) of a terahertz pulse light is generated.
  • step S1 the scanning control unit 203 controls the scanning unit 40 so that the terahertz pulse lights that are temporally separated and propagate through the optical paths L41, L42, and L43 are the positions P1 and P2 of the object S to be measured, respectively.
  • P3 is changed so that the relative positional relationship between the optical path of the terahertz pulsed light and the object S to be measured is changed.
  • the scanning unit 40 uses the galvanometer mirror 44 in order to change the position at which the terahertz pulse light is irradiated onto the object S to be measured.
  • the galvanometer mirror 44 it is also possible to realize a similar function to moving the measurement object S without using the galvanometer mirror 44. Specifically, it is as follows.
  • the scanning unit 40 is connected to the object to be measured S until the terahertz pulse light propagating in the optical path L42 reaches the object to be measured S.
  • the relative position with respect to the measurement optical unit 51 is changed. For example, the device under test S is moved in the direction of the arrow Ar2 so that the terahertz pulse light propagating through the optical path L42 reaches the position P2 of the device under test S.
  • the terahertz pulse light propagating through the optical path L42 passes through the position P2 of the object S to be measured, the terahertz pulse light propagating through the optical path L43 is received before the terahertz pulse light propagating through the optical path L43 reaches the object S to be measured.
  • the measured object S is moved in the direction of the arrow Ar2 so as to reach the position P3 of the measured object S.
  • the object to be measured S is moved to an arrow so that the terahertz pulse propagating in the optical path L41 reaches the new measurement position of the object to be measured S. Move in the direction of Ar2. Thereafter, the above operation is repeated.
  • the terahertz pulse light propagating through the optical path L41 is transmitted through the position P1 of the device under test S
  • the terahertz pulse light propagating through the optical path L42 is transmitted through the position P2 of the device under test S
  • the terahertz pulse propagates through the optical path L43. It has been described that light passes through the position P3 of the object S to be measured.
  • the combination of the optical path through which the terahertz pulse light propagates and the irradiation position of the object to be measured are not limited to the above.
  • the terahertz pulse light propagating through the optical path L41 passes through the position P2 of the object to be measured S
  • the terahertz pulse light propagating through the optical path L42 passes through the position P3 of the object to be measured S
  • the terahertz pulse light propagates through the optical path L43. May pass through the position P1 of the object S to be measured.
  • Other combinations may be used.
  • the scanning unit 40 transmits the optical path of the terahertz pulse light and the device under test S Is changed in synchronization with the time (timing) at which the terahertz pulse light propagated through different optical paths reaches the device under test S.
  • the terahertz pulse light propagating through the optical paths L41, L42, and L43 can be temporally separated from one outgoing terahertz pulse light from the transmitter 50. Thereby, the measurement object S can be measured in a short time.
  • the terahertz pulse light emitted from the transmitter 50 is converged (collimated) by the first condensing optical system 61 and then transmitted through the optical path length conversion unit 30.
  • the temporal separation of the terahertz pulse light propagating in the optical paths L41, L42, and L43 can be favorably performed.
  • a terahertz measuring device according to a third embodiment will be described with reference to the drawings.
  • the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the second embodiment.
  • the configuration of the optical path length conversion unit is different from that of the optical path length conversion unit 30 of the second embodiment.
  • FIG. 5 is a diagram schematically illustrating the measurement optical unit 51 in the third embodiment.
  • FIG. 5A is a simplified schematic diagram mainly showing the measurement optical unit 51 in the terahertz measurement apparatus 100, as in the case of FIG.
  • a galvanometer mirror 44 a first condensing optical system 61, a second condensing optical system 62, a third condensing optical system 63, and an optical path length conversion unit 33 are provided.
  • the optical path length conversion unit 33 is provided in the optical path between the first condensing optical system 61 and the second condensing optical system 62.
  • the optical path length conversion unit 33 sets three different optical path lengths will be described as an example.
  • the number of different optical path lengths to be set is not limited to this, but two However, it may be four or more.
  • the optical path length conversion unit 33 includes a first condensing optical system 61 and a second condensing optical system 62 between the transmitter 50 and the object S to be measured. Arranged between.
  • the optical path length conversion unit 33 includes an optical path length conversion plate 330 and a rotation unit 334 such as a motor that rotates the optical path length conversion plate 330.
  • the optical path length conversion plate 330 includes a first region 331, a second region 332, and a third region 333 having different thicknesses (lengths) along the propagation direction of the terahertz pulse light. Have. In the example shown in FIG.
  • the optical path length conversion plate 330 has a disk shape orthogonal to the propagation direction of the terahertz pulse light, and the first region 331 is formed every 120 ° with the center of the disk as the rotation axis. A second region 332 and a third region 333 are formed. The thickness along the propagation direction of the terahertz pulse light L4 increases in the order of the first region 331, the second region 332, and the third region 333.
  • the optical path length conversion plate 330 is configured to be rotatable by the rotation unit 334 with the center of the disc as the rotation axis.
  • the optical path length conversion plate 330 is arranged so that the rotation axis of the optical path length conversion plate 330 is positioned outside the optical path L4 of the terahertz pulse light. That is, the optical path length conversion plate 330 is arranged such that the first region 331, the second region 332, and the third region 333 are sequentially positioned on the optical path L4 of the terahertz pulse light by rotating.
  • the terahertz pulse light emitted from the transmitter 50 passes through any one of the first region 331, the second region 332, and the third region 333 of the optical path length conversion plate 330 and reaches the object S to be measured.
  • the optical path length conversion plate 330 is rotated at, for example, 1000 rotations / sec by the rotating unit 334 controlled by the control device 20. Thereby, the position where the terahertz pulse light emitted from the transmitter 50 at the pulse interval T passes through the optical path length conversion plate 330 can be sequentially switched to the first region 331, the second region 332, and the third region 333.
  • the optical path length conversion plate 330 is a rotatable disk, and the case where the thickness at the position of the optical path length conversion plate 330 through which the terahertz pulse light is transmitted is sequentially switched by rotation is exemplified. It is not limited to this.
  • the optical path length conversion plate 330 may be a rectangular flat plate having a first region 331, a second region 332, and a third region 333 having different thicknesses in the direction in which the terahertz pulse light propagates.
  • the optical path length conversion plate 330 can be sequentially switched in the thickness of the position of the optical path length conversion plate 330 through which the terahertz pulse light is transmitted by sliding in the direction intersecting the direction in which the terahertz pulse light propagates.
  • the optical path length through which the terahertz pulse light propagates when the terahertz pulse light is transmitted through the first region 331 of the optical path length conversion plate 330, when transmitted through the second region 332, and when transmitted through the third region 333. Therefore, there is a difference in the time (propagation time) from when the terahertz pulse light is emitted from the transmitter 50 until it reaches the receiver 80.
  • the distance along the propagation direction of the terahertz pulse light increases in the order of the first region 331, the second region 332, and the third region 333.
  • the propagation time of the terahertz pulse light transmitted through the first region 331 is the shortest
  • the propagation time of the terahertz pulse light transmitted through the second region 332 is the second shortest
  • the third region 333 is The propagation time of the transmitted terahertz pulse light is the longest.
  • the scanning control unit 203 controls the scanning unit 40 as follows.
  • the scanning unit 40 sets the direction of the reflecting surface of the galvanometer mirror 44 to the initial position, and controls so that the terahertz pulse light propagates through the optical path L41.
  • the center of the optical path L41 is indicated by a two-dot chain line in FIG.
  • only the outline of the optical path of the terahertz pulse light at that time is shown by a solid line in FIG.
  • the rotation of the optical path length conversion plate 330 is controlled so that the terahertz pulse light passes through the first region 331 of the optical path length conversion plate 330.
  • a position where the terahertz light irradiates the measurement object S is defined as P1.
  • the terahertz pulse light propagating in the optical path L42 passes through the position P1 of the object to be measured S
  • the terahertz pulse light propagating in the optical path L42 (only the center of the optical path is indicated by a one-dot chain line in FIG. 5A) is measured.
  • the scanning unit 40 changes the direction of the reflecting surface of the galvanometer mirror 44 so as to reach the position P2 of the object S.
  • the rotation of the optical path length conversion plate 330 is controlled so that the terahertz pulse light passes through the second region 332 of the optical path length conversion plate 330.
  • the scanning unit 40 changes the direction of the reflecting surface of the galvanometer mirror 44 so as to reach the position P3 of S.
  • the rotation of the optical path length conversion plate 330 is controlled so that the terahertz pulse light passes through the second region 332 of the optical path length conversion plate 330.
  • the scanning unit 40 moves the measurement object S in the direction of the arrow Ar3 so that the terahertz pulse propagating through the optical path L41 reaches the new measurement position of the measurement object S. That is, the change in the direction of the reflection surface of the galvanometer mirror 44 by the scanning unit 40 is performed in synchronization with the change in the time for the terahertz pulse light to reach the object S to be measured. Thereafter, the above operation is repeated.
  • FIG. 6 schematically shows time amplitude waveforms E1 (t), E2 (t), and E3 (t) of the terahertz pulse light that propagates through the optical paths L51, L52, and L53 and enters the receiver 80.
  • FIG. The time amplitude waveform E1 (t) of the tera health pulse light transmitted through the position P1 of the object S to be measured and propagated through the optical path L51 has a peak Pu1.
  • the time amplitude waveform E2 (t) of the terahealth pulsed light transmitted through the position P2 of the measurement object S and propagating through the optical path L52 has a peak Pu2.
  • the time amplitude waveform E3 (t) has a peak Pu3.
  • the delay time control unit 201 uses the probe pulse light to the receiver 80 with respect to the timing at which the pump pulse light irradiates the receiver 80.
  • the operation of the optical delay unit 10 is controlled so that the difference in irradiation timing gradually increases.
  • a predetermined number of times (for example, 800 times) of terahertz pulse light is emitted from the transmitter 50 for each of the peak Pu1, peak Pu2, and peak Pu3, and the terahertz pulse light transmitted through the object to be measured S is received by the receiver. 80 is incident.
  • the amplitudes of the delay times t2_1, t2_2,... T2_n are detected, and voltage signals corresponding to these amplitudes are output to the control device 20.
  • the amplitudes of the sampling positions Po2_1, Po2_2,... Po2_n of the time amplitude waveform E2 (t) of the terahertz pulse light at times t2_1, t2_2,..., T2_n are detected, and the voltage signal corresponding to these amplitudes is detected by the control device 20. Output to.
  • the amplitudes of the sampling positions Po3_1, Po3_2,... Po3_n of the time amplitude waveform E3 (t) of the terahertz pulse light at times t3_1, t3_2,... T3_n are detected, and voltage signals corresponding to these amplitudes are sent to the control device 20. Output.
  • the inspection unit 210 includes time amplitude waveforms E1 (t), E2 (t), and E3 (Terahertz pulse light transmitted through three different positions P1, P2, and P3 of the measurement object S generated by the measurement data generation unit 202.
  • E1 (t) time amplitude waveforms
  • E2 (t) Error-to-Fi
  • E3 Terhertz pulse light transmitted through three different positions P1, P2, and P3 of the measurement object S generated by the measurement data generation unit 202.
  • step S1 the control device 20 controls the rotating unit 334 to rotate the optical path length conversion plate 330, and the scanning control unit 203 determines the relative positional relationship between the optical path of the terahertz pulse light and the object S to be measured. change.
  • the terahertz pulse light that has propagated through the optical path L41 and transmitted through the first region 331 of the optical path length conversion plate 330 passes through the position P1 of the object S to be measured.
  • the terahertz pulse light that has propagated through the optical path L42 and transmitted through the second region 332 of the optical path length conversion plate 330 passes through the position P2 of the object S to be measured.
  • the terahertz pulse light that has propagated through the optical path L43 and transmitted through the third region 333 of the optical path length conversion plate 330 passes through the position P3 of the object S to be measured.
  • the terahertz pulse light that has propagated through the optical path L41 and transmitted through the first region 331 of the optical path length conversion plate 330 is transmitted through the position P1 of the object to be measured S, propagated through the optical path L42, and the second region of the optical path length conversion plate 330.
  • the terahertz pulse light that has passed through 332 passes through the position P2 of the object to be measured S, propagates through the optical path L43, and the terahertz pulse light that has passed through the third region 333 of the optical path length conversion plate 330 passes through the position P3 of the object to be measured S. Then explained.
  • the combination of the optical path through which the terahertz pulse light propagates, the transmission region of the optical path length conversion plate 330, and the irradiation position of the object to be measured is not limited to the above.
  • the terahertz pulse light that has propagated through the optical path L41 and transmitted through the second region 332 of the optical path length conversion plate 330 is transmitted through the position P3 of the measurement object S, propagated through the optical path L42, and the third region 333 of the optical path length conversion plate 330.
  • the terahertz pulse light that has passed through the first transmission point passes through the position P1 of the object to be measured S, propagates through the optical path L43, and passes through the first region 331 of the optical path length conversion plate 330. You may do it. Other combinations may be used.
  • the optical path length conversion unit 33 may be modified to be disposed between the laser light source 1 and the transmitter 50 instead of being disposed between the transmitter 50 and the object S to be measured. Such a configuration is shown in FIG.
  • the terahertz measurement device 100 includes a first condensing optical system 61, an optical path length conversion unit 33, and a second condensing optical system 62 in the optical path between the beam splitter 2 and the transmitter 50.
  • the optical path length conversion unit 33 includes an optical path length conversion plate 330 and a rotation unit 334.
  • the optical path length conversion plate 330 includes a first region 331, a second region 332, and a third region 333 (see FIG. 5B) having different thicknesses along the propagation direction of the pump pulse light.
  • the optical path length conversion plate 330 After collimating the pump pulse light branched by the beam splitter 2, the optical path length conversion plate 330 is rotated by the rotating unit 334 in synchronization with the timing at which the pump pulse light passes through the optical path length conversion plate 330. Accordingly, the pump pulse light sequentially passes through the first region 331, the second region 332, and the third region 333. As a result, a difference occurs in the timing at which the pump pulse light reaches the transmitter 50, and the pump pulse light sequentially reaches the transmitter 50 at three types of timing. As a result, the emission intervals of the terahertz pulse light emitted from the transmitter 50 are not equal, and the terahertz pulse light can reach the object to be measured at the same timing as in the third embodiment.
  • the optical path length conversion plate 330 sequentially switches the optical path length imparted to the terahertz pulse light. Thereby, the terahertz pulse light having a larger amplitude can be incident on the receiver 80.
  • the terahertz pulse light emitted from the transmitter 50 or the pump pulse light emitted from the laser light source 1 is converged (collimated) by the first condensing optical system 61 and then transmitted through the optical path length conversion plate 330. .
  • the timing of the terahertz pulse light or the pump pulse light can be changed favorably.
  • a terahertz measuring device according to a fourth embodiment will be described with reference to the drawings.
  • the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the first embodiment.
  • the terahertz measurement apparatus using the reflection measurement method that measures the reflected light of the terahertz pulse light irradiated to the object S to be measured is the terahertz using the transmission measurement method of the first embodiment. Different from the measuring device 100.
  • FIG. 7 is a diagram schematically illustrating a schematic configuration of the measurement optical unit 51 of the terahertz measurement apparatus 100 according to the fourth embodiment.
  • the measurement optical unit 51 of the terahertz measurement device 100 according to the present embodiment includes a beam splitter 41, a convex lens 42, an optical path length conversion unit 43, a galvano mirror 44, a first configuration as a configuration for performing measurement by a reflection measurement method.
  • a first condensing optical system 61 and a second condensing optical system 62 are provided.
  • the optical path length conversion unit 43 sets three different optical path lengths will be described as an example. However, the number of different optical path lengths to be set is not limited to this, and is two. However, it may be four or more.
  • a first condensing optical system 61 is disposed in the optical path between the transmitter 50 and the beam splitter 41.
  • the terahertz pulse light emitted from the transmitter 50 propagates through the optical path L4, is collimated by the first condensing optical system 61, passes through the optical path length conversion unit 43, is reflected by the beam splitter 41, and propagates to the galvanometer mirror 44. To do.
  • the terahertz pulse light that has been reflected by the galvanometer mirror 44 and whose propagation direction has been changed is condensed on the measurement object S by the convex lens 42 that is an objective optical system.
  • the terahertz pulse light reflected by the object to be measured S propagates in the optical path L5, is collimated by the convex lens 42, and then propagates to the galvanometer mirror 44.
  • the terahertz pulse light reflected by the galvanometer mirror 44 passes through the beam splitter 41, is collected by the second condensing optical system 62, and enters the receiver 80.
  • the galvanometer mirror 44 is controlled by the scanning control unit 203 of the control device 20 to change the angle of its reflection surface. Since the propagation direction of the reflected terahertz pulse light can be changed by changing the angle of the reflection surface of the galvanometer mirror 44, different measurement positions of the object to be measured S can be irradiated.
  • the optical path length conversion unit 43 includes a first region 431, a second region 432, and a second region 432 having different thicknesses along the propagation direction of the terahertz pulse light in the optical path L4.
  • a third region 433 is provided.
  • the first region 431, the second region 432, and the third region 434 are thicker in this order.
  • the terahertz pulse light emitted from the transmitter 50 has different optical path lengths depending on the transmission position of the optical path length conversion unit 43.
  • the terahertz pulse light transmitted through the first region 431 of the optical path length conversion unit 43 and propagating through the optical path L41 propagates through the optical path L51 and reaches the position P1 of the object S to be measured earliest.
  • the terahertz pulse light transmitted through the second region 432 of the optical path length conversion unit 43 and propagating through the optical path L42 propagates through the optical path L52 and reaches the position P2 of the object S to be measured second earlier.
  • the terahertz pulse light transmitted through the third region 433 of the optical path length conversion unit 43 and propagating through the optical path L433 propagates through the optical path L53 and finally reaches the position P3 of the object to be measured S.
  • the terahertz pulse light reflected by P1, P2, and P3 of the device under test S reaches the receiver 80 in this order.
  • the time amplitude waveform E (t) of the terahertz pulse light as shown in FIG. 2B is generated by the same procedure as in the second embodiment.
  • the amount of change in the angle of the reflecting surface of the galvanometer mirror 44 is set according to the measurement interval of the object S to be measured.
  • the operation performed by the terahertz measurement apparatus 100 according to the second embodiment can also be applied to the operation of the terahertz measurement apparatus 100 according to the present embodiment.
  • the optical path length conversion unit 43 is provided in the optical path between the first condensing optical system 61 and the beam splitter 41.
  • the optical path length conversion unit 43 is described as an example. May be provided in the optical path between the beam splitter 41 and the second condensing optical system 62.
  • the optical path length conversion unit 43 in the fourth embodiment has been described as having the same configuration as the optical path length conversion unit 30 similar to those in the first and second embodiments, but the third embodiment It is good also as a thing provided with the structure similar to the optical path length conversion part 33 (refer FIG. 5) in a form.
  • control of the galvanometer mirror 44 is performed in the same manner as in the third embodiment.
  • the same operational effects as those of the first to third embodiments can be obtained.
  • the terahertz measurement apparatus 100 can be configured without the measurement optical unit 51 having the beam splitter 41.
  • FIG. 8 schematically shows a measurement optical unit 51 having a configuration without the beam splitter 41. In FIG. 8, it is assumed that two different optical path lengths are set for the optical path of the terahertz pulse light for the sake of simplicity.
  • (A) is a side view of the measurement optical unit 51
  • (b) is an AA cross-sectional shape of the galvanometer mirror 45
  • (c) is a top view of the measurement object S
  • (d) is an optical path length conversion unit 43.
  • the transmitter 50 and the receiver 80 of the terahertz measuring device 100 are arrange
  • the center of the galvanometer mirror 45 is disposed on the opposite side of the object S to be measured away from the convex lens 42 at the focal length of the convex lens 42.
  • the galvanometer mirror 45 is formed so that its cross-sectional shape has two reflecting surfaces R1 and R2 bent at a predetermined angle at the center. That is, the galvanometer mirror 45 has two reflecting surfaces.
  • the terahertz pulse light emitted from the transmitter 50 propagates through the optical path L4 and is reflected by the lower region at (a) of the galvanometer mirror 45.
  • the galvanometer mirror 45 has the two reflecting surfaces R1 and R2
  • the terahertz pulse light is reflected and separated in two different directions by these reflecting surfaces R1 and R2, and the measured object S Positions P1 and P2 are reached, respectively.
  • the light is reflected by the reflecting surface R1, refracted in one region (right half region in FIG. 8) R3 of the convex lens 42, and reaches the object S to be measured.
  • the positions P1 and P2 of the object to be measured S are aligned in the direction perpendicular to the paper surface in (a).
  • the terahertz pulse light reflected at the positions P1 and P2 of the object to be measured S propagates through the optical path L5, is reflected by the reflecting surface R2 of the galvano mirror 45, and then passes through the optical path length conversion unit 43.
  • the optical path length conversion unit 43 has two regions having different thicknesses in the direction perpendicular to the paper surface in (a), and reflects the terahertz pulse light reflected at the position P1 and the position P2.
  • the terahertz pulse light is arranged so as to pass through a region having a different thickness.
  • the timing when the terahertz pulse light reflected at the position P1 and the terahertz pulse light reflected at the position P2 are transmitted through the optical path length conversion unit 43 and converged by the convex lens 42 and incident on the receiver 80 is different. That is, the terahertz pulse light reflected at the position P1 and the terahertz pulse light reflected at the position P2 are successively incident on the receiver 80.
  • the directions of the reflecting surfaces of the galvano mirror 45 are two surfaces R1 and R2, and the number of irradiation positions of the measurement positions irradiated by one terahertz pass is also P1. And 2 points of P2.
  • the number of reflection surfaces of the galvanometer mirror 45 it is possible to increase the number of irradiation positions of measurement positions irradiated by one terahertz pass.
  • FIG. 9A is a diagram schematically showing a part of the measurement optical unit 51 of the terahertz measurement apparatus 100 in the modification of the fourth embodiment
  • FIG. 9B is a diagram of the control apparatus 20 in this case. It is a block diagram which shows a structure.
  • a calibration member Ss is provided in the vicinity of the measurement object S.
  • the calibration member Ss is manufactured using a material having a known reflectance with respect to terahertz pulse light such as a resin material.
  • the control device 20 includes a storage unit 204 and a correction unit 205 as functions in addition to the delay time control unit 201, the measurement data generation unit 202, and the scanning control unit 203 illustrated in FIG.
  • a time amplitude waveform E (t) of the reflected terahertz pulse light of the terahertz pulse light irradiated on the calibration member Ss is stored in advance.
  • the correction unit 205 includes a time amplitude waveform E Albany (t) of the reflected terahertz pulse light of the calibration member Ss stored in the storage unit 204 and a time of the reflected terahertz pulse light of the terahertz pulse light actually irradiated on the measurement object S.
  • the amplitude waveform E (t) is compared to calculate a correction value for correcting an error associated with a variation in the terahertz pulse light amplitude.
  • the correction unit 205 corrects the time amplitude waveform E (t) of the reflected terahertz pulse light from the measurement object S using the calculated correction value. As a result, even when the time amplitude waveform E (t) of the reflected terahertz pulse light from the object S to be measured is affected by the variation factor during measurement, an accurate time amplitude waveform E (t) is obtained. Measurement accuracy can be maintained.
  • the terahertz measurement apparatus 100 according to the fourth embodiment is modified is described as an example.
  • the present invention is not limited to this, and the terahertz measurement apparatus 100 according to the first to third embodiments is used. Can be applied to.
  • optical path branching portions 81 and 82 constituted by, for example, MEMS type or mechanical type optical switches are arranged in the optical path between the beam splitter 2 and the transmitter 50.
  • the pump pulse light propagating from the beam splitter 2 along the optical path L ⁇ b> 2 is branched by the optical path branching unit 81, then propagates through the three optical paths L ⁇ b> 21, L ⁇ b> 22, and L ⁇ b> 23 having different optical path lengths.
  • the three optical paths have different optical path lengths.
  • one pump pulse light emitted from the laser light source 1 is temporally separated into three continuous pump pulse lights and sequentially radiates the transmitter 50.
  • the transmitter 50 is irradiated with the pump pulse light three times. Therefore, the transmitter 50 emits terahertz pulse light at shorter time intervals.
  • FIG. 13 schematically shows the main configuration of the terahertz measuring apparatus 100 in this case.
  • FIG. 13 schematically shows a case where a waveguide 47 is provided instead of the optical path length conversion unit 30 of the terahertz measurement apparatus 100 shown in FIG. 1.
  • Other structures are the same as those of the terahertz measuring apparatus 100 of FIG.
  • the waveguide 47 includes, for example, a first waveguide 411, a second waveguide 412, and a third waveguide 413.
  • Each of the waveguides 411, 412, and 413 can be configured by a core having a core formed of, for example, Teflon (registered trademark) or silicon.
  • Teflon registered trademark
  • the lengths of the waveguides 411 to 413 are different from each other along the propagation direction of the terahertz pulse light propagating through the optical path L4, and the first waveguide 411, the second waveguide 412, and the third waveguide are different. The length increases in the order of the waveguide 413.
  • the first lens group 71 is provided at the exit side (receiver 80 side) end of each waveguide 47, and the third lens group 73 is provided at the entrance side (transmitter 50 side) end.
  • the first lens group 71 includes the 1-1 lens unit 711, the 1-2 lens unit 712, and the 1-3 lens unit 713, and includes the first waveguide 411 and the second waveguide, respectively. It is provided at the exit end of the waveguide 412 and the third waveguide 413.
  • the third lens group 73 includes a 3-1 lens portion 731, a 3-2 lens portion 732, and a 3-3 lens portion 733, and the first waveguide 411, the second waveguide 412, and the third lens portion 733, respectively. Provided at the incident end of the waveguide 413.
  • the terahertz pulse light reaches the waveguide 47 from the first condensing optical system 61 via the third lens group 73 and transmits through the first waveguide 411, transmits through the second waveguide 412,
  • the optical paths L41, L42, and L43 having different optical path lengths from the case of transmitting through the three waveguides 413 are formed.
  • the terahertz pulse light propagating through the optical paths L41, L42, and L43 is temporally separated.
  • the light reaches and passes through three different positions P1, P2, and P3 of the object to be measured S at different timings. In the example illustrated in FIG.
  • the third lens group 73 is provided at the incident end of the waveguide 47 as an example, but the third lens group 73 may not be provided. In this case, it can be configured such that the incident end of the waveguide 47 is in close contact with the outgoing end of the transmitter 50.
  • the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

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Abstract

La présente invention concerne un dispositif de mesure térahertz comprenant : un émetteur térahertz transmettant une lumière térahertz vers un objet de mesure en raison de l'alimentation en lumière pulsée ; un récepteur térahertz recevant de la lumière térahertz provenant de l'objet de mesure ; et un élément de changement de temps d'arrivée de lumière térahertz changeant la durée pendant laquelle la lumière térahertz émise par l'émetteur térahertz atteint le récepteur térahertz, par rapport à la durée pendant laquelle la lumière pulsée est générée.
PCT/JP2017/006930 2017-02-23 2017-02-23 Dispositif de mesure térahertz, dispositif d'inspection, procédé de mesure térahertz et procédé d'inspection WO2018154690A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110108664A (zh) * 2019-04-16 2019-08-09 国网江苏省电力有限公司电力科学研究院 一种复合材料横担缺陷的无损检测方法
CN115290597A (zh) * 2022-10-08 2022-11-04 首都师范大学 基于太赫兹技术的涂层紧贴型无黏结缺陷检测方法及系统

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008076159A (ja) * 2006-09-20 2008-04-03 Aisin Seiki Co Ltd 内部欠陥検査方法及び内部欠陥検査装置
JP2008096200A (ja) * 2006-10-10 2008-04-24 Aisin Seiki Co Ltd 形状検査方法及び形状検査装置
JP2013044727A (ja) * 2011-08-26 2013-03-04 Fujitsu Ltd 電磁波イメージング装置
WO2013046249A1 (fr) * 2011-09-26 2013-04-04 パイオニア株式会社 Dispositif d'émission d'ondes électromagnétiques, dispositif de détection d'ondes électromagnétiques, et dispositif d'imagerie les comprenant

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008076159A (ja) * 2006-09-20 2008-04-03 Aisin Seiki Co Ltd 内部欠陥検査方法及び内部欠陥検査装置
JP2008096200A (ja) * 2006-10-10 2008-04-24 Aisin Seiki Co Ltd 形状検査方法及び形状検査装置
JP2013044727A (ja) * 2011-08-26 2013-03-04 Fujitsu Ltd 電磁波イメージング装置
WO2013046249A1 (fr) * 2011-09-26 2013-04-04 パイオニア株式会社 Dispositif d'émission d'ondes électromagnétiques, dispositif de détection d'ondes électromagnétiques, et dispositif d'imagerie les comprenant

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110108664A (zh) * 2019-04-16 2019-08-09 国网江苏省电力有限公司电力科学研究院 一种复合材料横担缺陷的无损检测方法
CN115290597A (zh) * 2022-10-08 2022-11-04 首都师范大学 基于太赫兹技术的涂层紧贴型无黏结缺陷检测方法及系统

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