WO2022049979A1 - Inspection device and inspection method - Google Patents

Inspection device and inspection method Download PDF

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Publication number
WO2022049979A1
WO2022049979A1 PCT/JP2021/028987 JP2021028987W WO2022049979A1 WO 2022049979 A1 WO2022049979 A1 WO 2022049979A1 JP 2021028987 W JP2021028987 W JP 2021028987W WO 2022049979 A1 WO2022049979 A1 WO 2022049979A1
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data
inspection
odpl
mapping data
omnidirectional
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PCT/JP2021/028987
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French (fr)
Japanese (ja)
Inventor
賢一郎 池村
一信 小島
重英 秩父
和也 井口
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浜松ホトニクス株式会社
国立大学法人東北大学
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Priority to JP2022546180A priority Critical patent/JPWO2022049979A1/ja
Publication of WO2022049979A1 publication Critical patent/WO2022049979A1/en

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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
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • 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
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence
    • 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
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination

Definitions

  • This disclosure relates to inspection equipment and inspection methods.
  • Luminescence measurement is a method of irradiating an object to be inspected with a beam and measuring the light generated when the excited electrons return to the ground state.
  • PL measurement light is used as a beam
  • cathode luminescence measurement an electron beam is used as a beam.
  • ODPL measurement omnidirectional photoluminescence measurement
  • the ODPL measurement is a method of measuring the number of photons of excitation light absorbed by an object to be inspected and the number of emitted photons in all directions using an integrating sphere.
  • the emission quantum efficiency of band-end emission affected by non-radiation recombination including structural defects can be calculated, so that defects can be quantified.
  • Devices for measuring luminescence are widely used in general.
  • the inspection function of the device is to be expanded for the purpose of quantifying defects and improving reproducibility, it is necessary to newly introduce another device such as a device for performing ODPL measurement.
  • the measurement accuracy due to the system may vary, such as the position shift of the beam with respect to the inspection object and the difference in the beam characteristics between the devices. Therefore, a technique capable of easily expanding the inspection function without causing such a problem has been desired.
  • the present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide an inspection device and a measurement method capable of easily expanding the inspection function.
  • the inspection apparatus detects a stage on which an inspection object is placed, a beam source that generates a beam to irradiate the inspection object, and light generated by the inspection object by the beam irradiation.
  • the optical system that guides the beam to the inspection object on the stage and guides the light generated by the inspection object to the photodetector, and the omnidirectional data on the omnidirectional light generated from the inspection object. It also includes a processing unit that converts one-sided data regarding one-sided light among the lights detected by the photodetector.
  • This inspection device detects the light generated in the inspection object, and the one-sided data regarding the one-sided light among the detected lights is based on the omnidirectional data regarding the omnidirectional light generated from the inspection object. Convert. In this way, by converting the one-sided data using the omnidirectional data, it is possible to acquire data different from the one-sided data without newly introducing a device different from the device for measuring the one-sided data. .. Therefore, it is possible to easily expand the inspection function while avoiding the problem of system-derived measurement accuracy variation such as increased cost burden, beam misalignment with respect to the inspection object between devices, and difference in beam characteristics. It will be possible.
  • the processing unit may generate the first mapping data regarding the one-sided data. As a result, the distribution of the one-sided data in the inspection target can be obtained, and the inspection of the inspection target can be suitably performed.
  • the processing unit may generate a second mapping data regarding the omnidirectional data from the first mapping data based on the omnidirectional data.
  • the distribution of omnidirectional data in the inspection target can be acquired, and the inspection of the inspection target can be suitably performed.
  • by combining the first mapping data and the omnidirectional data it is possible to increase the resolution of the omnidirectional data.
  • Omnidirectional data about the inspection target may be stored in advance in the processing unit. In this case, the time required for the inspection can be shortened.
  • the optical system has a first optical system for acquiring one-sided data, a second optical system for acquiring omnidirectional data, and a switching unit for switching between the first optical system and the second optical system. You may be doing it. In this case, both the one-sided data and the omnidirectional data can be acquired without newly introducing a device different from the device for measuring the one-sided data.
  • the beam source may generate an excitation beam that excites the object to be inspected.
  • the inspection function can be sufficiently expanded based on the measurement of the excitation beam absorbed by the inspection object and the measurement of the light generated in the inspection object by the irradiation of the excitation beam.
  • the inspection method is one of an irradiation step of irradiating an inspection object with a beam, a light detection step of detecting light generated in the inspection object, and light detected in the light detection step. It includes an acquisition step of acquiring one-sided data regarding directional light, and a processing step of converting one-sided data based on omnidirectional data related to omnidirectional light generated from an inspection object.
  • the light generated in the inspection object is detected, and the one-sided data regarding the one-sided light among the detected lights is based on the omnidirectional data regarding the omnidirectional light generated from the inspection object. Convert. In this way, by converting the one-sided data using the omnidirectional data, it is possible to acquire data different from the one-sided data without newly introducing a device different from the device for measuring the one-sided data. .. Therefore, it is possible to easily expand the inspection function while avoiding the problem of system-derived measurement accuracy variation such as increased cost burden, beam misalignment with respect to the inspection object between devices, and difference in beam characteristics. It will be possible.
  • the first mapping data regarding the one-sided data may be generated.
  • the distribution of the one-sided data in the inspection target can be acquired, and the inspection of the inspection target can be suitably performed.
  • the second mapping data related to the omnidirectional data may be generated from the first mapping data based on the omnidirectional data.
  • the distribution of omnidirectional data in the inspection target can be acquired, and the inspection of the inspection target can be suitably performed.
  • the first mapping data and the omnidirectional data it is possible to increase the resolution of the omnidirectional data.
  • omnidirectional data about the inspection target acquired in advance may be used. In this case, the time required for the inspection can be shortened.
  • the first optical system for acquiring unidirectional data and the second optical system for acquiring omnidirectional data may be switched, and in the acquisition step, unidirectional data and omnidirectional data may be acquired. ..
  • both the one-sided data and the omnidirectional data can be acquired without newly introducing a device different from the device for measuring the one-sided data.
  • an excitation beam that excites the object to be inspected may be irradiated.
  • the inspection function can be sufficiently expanded based on the measurement of the excitation beam absorbed by the inspection object and the measurement of the light generated in the inspection object by the irradiation of the excitation beam.
  • the inspection function can be easily expanded.
  • FIG. 1 It is a schematic diagram which shows the state after the optical system switching in the inspection apparatus shown in FIG. It is a block diagram which shows the structure of the processing part of the inspection apparatus shown in FIG. It is a flowchart which shows an example of PL mapping data generation processing in the inspection apparatus shown in FIG. It is a flowchart which shows an example of the ODPL mapping data generation processing in the inspection apparatus shown in FIG. It is a schematic diagram which shows the modification of the 2nd optical system.
  • FIG. 1 is a schematic diagram showing the configuration of the inspection device according to the first embodiment of the present disclosure.
  • the inspection device 1A shown in the figure is a device for performing non-destructive inspection of the inspection object S.
  • a compound semiconductor wafer is exemplified as the inspection object S.
  • the inspection object S is a gallium nitride (GaN) semiconductor wafer.
  • GaN semiconductors are expected to be applied to high-frequency devices and power devices as well as visible / ultraviolet light emitting devices. It is known that the characteristics of devices using GaN semiconductors are greatly affected by structural defects such as through dislocations, point defects, and contamination with trace impurities.
  • the inspection device 1A is configured as a device for inspecting both the distribution of structural defects and the quantification of defects of a GaN semiconductor wafer in order to improve the yield of the device and promote mass production.
  • the one-sided data regarding the one-sided light generated from the inspection object S and all the one-sided data generated from the inspection object S are inspected.
  • the one-sided data is data based on luminescence measurement such as photoluminescence measurement (hereinafter referred to as PL measurement).
  • the omnidirectional data is data based on omnidirectional photoluminescence measurement (hereinafter referred to as ODPL measurement).
  • Luminescence measurement is a method of irradiating an object to be inspected with a beam and measuring the light generated when the electrons excited by the beam return to the ground state.
  • PL measurement light is used as a beam
  • cathode luminescence measurement an electron beam is used as a beam. While it is possible to detect the distribution of structural defects in the inspection object in the light emission measurement, from the viewpoint of quality assurance of the semiconductor wafer, it is required to quantify the defects and improve the reproducibility.
  • ODPL measurement is a method of measuring the number of photons of excitation light absorbed by an object to be inspected and the number of emitted photons in all directions using an integrating sphere.
  • the emission quantum efficiency (internal quantum efficiency (IQE) or external quantum efficiency (EQE)) of band-end emission affected by non-radiative recombination including structural defects can be calculated, so defects can be quantified.
  • Internal quantum efficiency (IQE) is the ratio of the number of emitted photons generated in the inspection object to the number of photons in the excitation light absorbed by the inspection object.
  • External quantum efficiency (EQE) is the ratio of the number of emitted photons emitted to the outside of the inspection object to the number of photons of the excitation light absorbed by the inspection object.
  • the spatial resolution of PL measurement when using an objective lens is about several ⁇ m to several sub ⁇ m.
  • the spatial resolution of the ODPL measurement is about several hundred ⁇ m to several tens of ⁇ m, which is about one to two orders of magnitude lower than the spatial resolution of the PL measurement.
  • the inspection device 1A can acquire high-resolution ODPL data by converting the one-sided data (PL data) based on the omnidirectional data (ODPL data).
  • the inspection function of the inspection device 1A can be easily expanded, and both the distribution of structural defects and the quantification of defects of the GaN semiconductor wafer can be inspected with high accuracy in one device. Can be done.
  • the inspection device 1A includes a stage 2, a beam source 3, a photodetector 4, and an optical system 5. Further, as shown in FIG. 2, the inspection device 1A includes a processing unit 21 and a display unit 26.
  • the stage 2 has a sample stage 6 on which an object to be inspected is placed, an X stage 7 capable of scanning the sample stage 6 in the X direction, and a Y stage 8 capable of scanning the sample stage 6 in the Y direction.
  • the X direction is one direction in the in-plane direction of the inspection object S
  • the Y direction is a direction orthogonal to the Y direction in the in-plane direction of the inspection object S.
  • the Z direction is a direction orthogonal to the X direction and the Y direction, and corresponds to the thickness direction of the inspection object S.
  • the sample stage 6, the X stage 7, and the Y stage 8 are all installed on the base plate 9.
  • the beam source 3 is a portion that generates a beam L to irradiate the inspection object S.
  • the emission surface of the beam L in the beam source 3 is arranged so as to face the X direction, for example, and is optically connected to the optical system 5.
  • an excitation light source 11 that outputs excitation light L1 for exciting the inspection object S can be used.
  • the excitation light source 11 may be, for example, either a coherent light source or an incoherent light source.
  • the coherent light source examples include an excima laser (wavelength 193 nm), a YAG laser second harmonic (wavelength 532 nm), a YAG laser fourth harmonic (wavelength 266 nm), a semiconductor laser (for example, an InGaN semiconductor laser (wavelength 375 nm to 530 nm), red). (Semiconductor laser, infrared semiconductor laser) and the like can be used.
  • a mercury lamp wavelength 365 nm
  • an LED light source or the like can be used.
  • the excitation light L1 output from the excitation light source 11 may be either pulse light or CW light.
  • the photodetector 4 is a portion that detects the light L2 generated in the inspection object S by the irradiation of the beam L.
  • the detection surface of the photodetector 4 is arranged so as to face the stage 2 side in the Z direction, for example, and is optically connected to the optical system 5.
  • the photodetector 4 detects the light L2 generated when the electrons excited by the inspection object S by the irradiation of the excitation light L1 return to the ground state.
  • the photodetector 4 outputs a signal indicating the detection result to the processing unit 21 (see FIG. 2).
  • the photodetector 4 for example, CMOS, CCD, EM-CDCD, photomultiplier tube, SiPM (MPPC), APD (SPAD), photodiode (including array-shaped one) and the like can be used.
  • the optical system 5 is a portion that guides the beam L from the beam source 3 to the inspection object S on the stage 2 and guides the light L2 generated by the inspection object S to the photodetector 4. More specifically, the optical system 5 includes an objective lens 12 and a filter holder 13. The objective lens 12 is provided on the Z stage 14 that can scan in the Z direction.
  • the filter holder 13 includes a first filter 15 and a second filter 16. The filter holder 13 is slidably provided in the X direction, and one of the first filter 15 and the second filter 16 is arranged in the optical path of the optical system 5.
  • the first filter 15 is a filter used for PL measurement.
  • the first filter 15 transmits at least a part of the light L2 generated in the inspection object S by the irradiation of the excitation light L1 and guides the light to the photodetector 4.
  • the second filter 16 is a filter used for reflection measurement.
  • the reflection measurement is a measurement for extracting an abnormal point by examining the reflected state of the excited light L1 on the surface of the inspection object S.
  • the second filter 16 is arranged in the optical path of the optical system 5, at least a part of the excitation light L1 from the excitation light source 11 is reflected and guided to the inspection object S through the objective lens 12.
  • the second filter 16 transmits at least a part of the excitation light L1 reflected by the inspection object S and guides the light to the photodetector 4.
  • the numerical aperture NA of the objective lens 12 is, for example, about 0.5.
  • a dichroic mirror, a bandpass filter, or the like is used as the second filter 16 for example.
  • the processing unit 21 is a unit that performs data processing based on the detection signal output from the photodetector 4.
  • the processing unit 21 is physically a computer including a memory such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, and a storage unit such as a hard disk. Examples of such a computer include a personal computer, a cloud server, a smart device (smartphone, tablet terminal, etc.) and the like.
  • the processing unit 21 serves as the PL mapping data generation unit 22, the reflection mapping data generation unit 23, and the high-resolution ODPL mapping data generation unit 24, as shown in FIG. Function.
  • the processing unit 21 has an ODPL mapping data storage unit 25.
  • the processing unit 21 is connected to a display unit 26 such as a monitor so that information can be communicated.
  • the PL mapping data generation unit 22 is a part that generates PL mapping data (first mapping data) related to PL data (one-sided data).
  • the PL mapping data generation unit 22 generates PL mapping data for the inspection object S based on the detection signal of the photodetector 4 at the time of PL measurement and the measurement coordinates thereof.
  • the PL mapping data generation unit 22 outputs the generated PL mapping data to the high-resolution ODPL mapping data generation unit 24.
  • the reflection mapping data generation unit 23 is a part that generates mapping data related to the reflection data.
  • the reflection mapping data generation unit 23 generates reflection mapping data for the inspection object S based on the detection signal of the photodetector 4 at the time of reflection measurement and the measurement coordinates thereof.
  • the reflection mapping data generation unit 23 outputs the generated reflection mapping data to the high-resolution ODPL mapping data generation unit 24.
  • the high-resolution ODPL mapping data generation unit 24 is a portion that generates high-resolution ODPL mapping data (second mapping data) from PL mapping data (first mapping data) based on ODPL data (omnidirectional data). ..
  • the ODPL mapping data for the inspection object S is stored in advance in the ODPL mapping data storage unit 25.
  • the high-resolution ODPL mapping data generation unit 24 When the high-resolution ODPL mapping data generation unit 24 receives the PL mapping data from the PL mapping data generation unit 22, the high-resolution ODPL mapping data generation unit 24 refers to the ODPL mapping data stored in the ODPL mapping data storage unit 25, and uses the ODPL mapping data to PL. Convert the mapping data to high resolution ODPL mapping data.
  • the high-resolution ODPL mapping data generation unit 24 outputs an inspection result image based on the generated high-resolution ODPL mapping data to the display unit 26.
  • the high-resolution ODPL mapping data generation unit 24 may output an image in which the generated high-resolution ODPL mapping data and the PL mapping data are superimposed to the display unit 26 as an inspection result image.
  • the ODPL mapping data stored in advance in the ODPL mapping data storage unit 25 is, for example, data obtained by prior ODPL measurement. This data is acquired when the inspection target S is a GaN semiconductor wafer, for example, by performing ODPL measurement in advance on a cutting sample of a GaN semiconductor wafer that is assumed to have the same doping concentration and defects in the same lot. can do.
  • the following equations (1) to (3) can be used for the conversion of the PL mapping data.
  • the ⁇ ODPL (x 0 , y 0 ) is the emission quantum efficiency (internal quantum efficiency (internal quantum efficiency (internal quantum efficiency (internal quantum efficiency)) obtained by the ODPL measurement at the coordinates (x 0 , y 0 ) of the inspection object S.
  • IQE internal quantum efficiency
  • EQE external quantum efficiency
  • PN emPL (x, y) is the number of luminescent photons obtained by PL measurement at the coordinates (x, y) of the inspection object S.
  • StartWL is the minimum wavelength in the target emission region of the inspection target S.
  • EndWL is the maximum wavelength in the target emission region of the inspection target S.
  • I ( ⁇ , x, y) is the emission intensity obtained by PL measurement at the coordinates (x, y) of the inspection object S.
  • WL ( ⁇ ) is the wavelength in the light emitting region, and ⁇ is the conversion coefficient.
  • the above equations (1) to (3) obtain a division value obtained by dividing the emission quantum efficiency at each coordinate of the inspection object S at the time of ODPL measurement by the number of emission photons at each coordinate of the inspection object S at the time of PL measurement. It is a thing.
  • IQE internal quantum efficiency
  • EQE external quantum efficiency
  • the irradiation condition of the excitation light L1 to the inspection object S it is necessary that the wavelength or the spot size of the excitation light L1 can be confirmed and the irradiance of the excitation light L1 is constant. Further, it is necessary that the angle of incidence of the excitation light L1 on the inspection object S is constant.
  • the conversion from the PL mapping data to the high-resolution ODPL mapping data is preferably applied to a region where the absorption amount of the excitation light L1 in the inspection object S is constant.
  • the determination of the absorption amount of the excitation light L1 is performed by confirming that the polished state of the surface of the inspection object S is constant, or confirming that the reflection amount of the excitation light L1 at the time of PL measurement is constant.
  • the absorption amount of the excitation light L1 is determined by measuring the reflection amount of the excitation light L1 at the time of the latter PL measurement. That is, when the high-resolution ODPL mapping data generation unit 24 receives the reflection mapping data from the reflection mapping data generation unit 23, the high-resolution ODPL mapping data generation unit 24 compares the reflection amount at each coordinate of the inspection object S with a predetermined threshold value based on the reflection mapping data. .. The high-resolution ODPL mapping data generation unit 24 can extract coordinates whose reflection amount exceeds the threshold value or coordinates below the threshold value as abnormal points, and can exclude data about those coordinates from the inspection result image.
  • FIG. 3 is a diagram showing an example of ODPL mapping data.
  • a GaN semiconductor wafer having a diameter of 2 inches was used as an inspection target.
  • the spot diameter of the excitation light was ⁇ 100 ⁇ m, and the measurement interval was 2 mm pitch.
  • the EQE values at each coordinate of the GaN semiconductor wafer are mapped by color coding by scale.
  • FIG. 4 is PL mapping data for the same sample, and the inside of the broken line frame A in FIG. 3 is enlarged and shown.
  • the black spot portion in FIG. 4 is considered to be a portion where the emission intensity is reduced due to the through dislocation of the GaN semiconductor wafer.
  • the EQE in the dashed line frame A is estimated to be 0.3%. Therefore, by converting the PL mapping data using the above equations (1) to (3), high-resolution ODPL mapping data can be acquired as shown in FIG. According to the high-resolution ODPL mapping data shown in FIG. 5, defects can be quantified by ODPL measurement (EQE), and the distribution of structural defects can be confirmed by PL measurement.
  • the inspection device 1A the PL mapping data generation process and the high-resolution ODPL mapping data generation process are executed in this order when inspecting the inspection object S.
  • FIG. 6 is a flowchart showing an example of PL mapping data generation processing.
  • the number n of measurement coordinates (x, y) is set according to the size of the inspection object S (step S01).
  • the stage 2 is driven, and the irradiation position of the excitation light L1 moves to the measurement point i in the inspection object S (step S02).
  • the first filter 15 is arranged on the optical path of the optical system 5.
  • the excitation light L1 is irradiated to the inspection object S, and the PL measurement at the measurement point i is executed (step S03).
  • the filter is switched (step S04). That is, the filter holder 13 slides in the X direction, and the second filter 16 is arranged on the optical path of the optical system 5. Then, the excitation light L1 is irradiated to the inspection object S, and the reflection measurement at the measurement point i is executed (step S05). After finishing the PL measurement and the reflection measurement, it is determined whether or not the measurement point i has reached n (step S06). When it is determined that the measurement point i has reached n, PL mapping data based on the PL measurement result at each coordinate and reflection mapping data based on the reflection measurement result at each coordinate are generated, and the PL mapping data generation process is performed. finish.
  • step S02 If it is determined that the measurement point i has not reached n, the process returns to step S02, the irradiation position of the excitation light L1 is moved to the measurement point (i + 1), and then the processes of steps S03 to S06 are repeatedly executed. ..
  • FIG. 7 is a flowchart showing an example of high resolution ODPL mapping data generation processing.
  • the PL mapping data generated in the PL mapping data generation process is referred to (step S11).
  • the PL mapping data generated in the PL mapping data generation process is referenced (step S12). Either step S11 or step S12 may be executed first.
  • the reflection amount of the excitation light L1 is compared with the threshold value, and the coordinates where the reflection amount is out of the threshold value are extracted as abnormal points (step S13).
  • step S14 After extracting the abnormal points, the ODPL mapping data stored in the ODPL mapping data storage unit 25 is referred to (step S14). Based on this ODPL mapping data, conversion of PL mapping data using the above equations (1) to (3) is performed (step S15). As a result, high-resolution ODPL mapping data is generated (step S16), and the high-resolution ODPL mapping data generation process is completed.
  • the inspection device 1A detects the light L2 generated in the inspection target object S, and collects PL data (one-sided data) related to the one-order light of the detected light L2 in the inspection target object S. Converts based on ODPL data (omnidirectional data) related to omnidirectional light generated from. In this way, by converting the PL data using the ODPL data, data different from the PL data can be acquired and the inspection object S can be obtained without newly introducing an ODPL measuring device different from the PL measuring device. Can be inspected. Therefore, the inspection function can be easily expanded while avoiding the problems of system-derived measurement accuracy variation such as an increase in cost burden, a positional deviation of the beam L with respect to the inspection object S between the devices, and a difference in beam characteristics. be able to.
  • the processing unit 21 In the inspection device 1A, the processing unit 21 generates PL mapping data (first mapping data) related to PL data. As a result, the distribution of PL data in the inspection target S can be acquired, and the inspection of the inspection target S can be suitably performed.
  • the processing unit 21 In the inspection device 1A, the processing unit 21 generates high-resolution ODPL mapping data (second mapping data) related to omnidirectional data from the PL mapping data based on the ODPL data. As a result, the distribution of ODPL data in the inspection target S can be acquired, and the inspection of the inspection target S can be suitably performed. Further, by combining the PL mapping data and the ODPL data, it is possible to increase the resolution of the ODPL data.
  • the ODPL data for the inspection target S is stored in advance in the processing unit 21. As a result, it is possible to save the trouble of acquiring ODPL data for each inspection target object S, and it is possible to shorten the time required for inspection.
  • the beam source 3 generates the excitation light L1 that excites the inspection object S. This makes it possible to sufficiently expand the inspection function based on the measurement of the excitation light L2 absorbed by the inspection object S and the measurement of the light generated in the inspection object S by the irradiation of the excitation light L2. .. [Second Embodiment]
  • FIG. 8 is a schematic diagram showing the configuration of the inspection device according to the second embodiment of the present disclosure.
  • the optical system 5 has the first optical system 5A (see FIG. 8) for acquiring PL data (one-sided data) and the ODPL data (all).
  • the first embodiment is performed in that it has a second optical system 5B (see FIG. 9) for acquiring (orientation data) and a switching unit 31 for switching between the first optical system 5A and the second optical system 5B. It is different from the morphology.
  • the first optical system 5A has the same configuration as the optical system 5 of the inspection device 1A of the first embodiment.
  • the second optical system 5B differs from the first optical system 5A in that the integrating sphere 33 is arranged on the optical path instead of the objective lens 12.
  • the switching unit 31 is configured by an XZ stage 32 that can scan in the X direction.
  • the objective lens 12 and the integrating sphere 33 are provided on the lower surface side of the XZ stage 32 so as to be separated from each other in the X direction.
  • the XZ stage 32 scans in the X direction, one of the objective lens 12 and the integrating sphere 33 is arranged in the optical path of the optical system 5. As shown in FIG.
  • the integrating sphere 33 is optically connected to the spectroscope 34.
  • the processing unit 21 has the PL mapping data generation unit 22 described above and the ODPL mapping data generation unit 35.
  • the light L2 generated in the inspection object S by the irradiation of the excitation light L1 is spatially integrated by repeating diffuse reflection in the integrating sphere 33, and then guided to the spectroscope 34 via the optical fiber F.
  • the spectroscope 34 outputs a result signal based on the detection result to the ODPL mapping data generation unit 35.
  • the ODPL mapping data generation unit 35 is a part that generates ODPL mapping data related to ODPL data (omnidirectional data).
  • the ODPL mapping data generation unit 35 generates ODPL mapping data for the inspection object S based on the detection signal of the spectroscope 34 at the time of ODPL measurement and the measurement coordinates thereof.
  • the ODPL mapping data generation unit 35 outputs the generated ODPL mapping data to the display unit 26.
  • the inspection device 1B the PL mapping data generation process and the ODPL mapping data generation process are selectively executed in the inspection of the inspection object S.
  • FIG. 11 is a flowchart showing an example of PL mapping data generation processing.
  • the number n of measurement coordinates (x, y) is set according to the size of the inspection object S (step S21).
  • the XZ stage 32 is driven, and the objective lens 12 is arranged in the optical path of the optical system 5.
  • the first optical system 5A for acquiring PL data is set (step S22).
  • the stage 2 is driven and the irradiation position of the excitation light L1 moves to the measurement point i in the inspection object S (step S23).
  • the first filter 15 is arranged on the optical path of the first optical system 5A.
  • the excitation light L1 is irradiated to the inspection object S, and the PL measurement at the measurement point i is executed (step S24).
  • step S25 After completing the PL measurement at the measurement point i, it is determined whether or not the measurement point i has reached n (step S25). When it is determined that the measurement point i has reached n, PL mapping data based on the PL measurement result at each coordinate is generated, and the PL mapping data generation process ends. If it is determined that the measurement point i has not reached n, the process returns to step S23, the irradiation position of the excitation light L1 is moved to the measurement point (i + 1), and then the processes of steps S23 to S25 are repeatedly executed. ..
  • FIG. 12 is a flowchart showing an example of the ODPL mapping data generation process.
  • the number n of measurement coordinates (x, y) is set according to the size of the inspection object S (step S31).
  • the XZ stage 32 is driven, and the integrating sphere 33 is arranged in the optical path of the optical system 5.
  • the second optical system 5B for acquiring ODPL data is set (step S32).
  • the stage 2 is driven and the irradiation position of the excitation light L1 moves to the measurement point i in the inspection object S (step S33).
  • the first filter 15 is arranged on the optical path of the second optical system 5B.
  • the excitation light L1 is irradiated to the inspection object S, and the ODPL measurement at the measurement point i is executed (step S34).
  • step S35 After finishing the ODPL measurement at the measurement point i, it is determined whether or not the measurement point i has reached n (step S35). When it is determined that the measurement point i has reached n, ODPL mapping data based on the ODPL measurement result at each coordinate is generated, and the ODPL mapping data generation process ends. If it is determined that the measurement point i has not reached n, the process returns to step S33, the irradiation position of the excitation light L1 is moved to the measurement point (i + 1), and then the processes of steps S33 to S35 are repeatedly executed. ..
  • the optical system 5 has a first optical system 5A for acquiring PL data (one-sided data), a second optical system 5B for acquiring ODPL data (omnidirectional data), and the like. It has a switching unit 31 for switching between the first optical system 5A and the second optical system 5B.
  • both PL data and ODPL data can be acquired without newly introducing a device different from the device for measuring PL data.
  • Having both PL data and ODPL data acquisition functions in the same device can solve cost problems, and is derived from the system such as the position shift of the beam L with respect to the inspection object S and the difference in beam characteristics between the devices. It is also possible to avoid variations in the measurement accuracy of.
  • the distance between the integrating sphere 33 and the inspection object S is 0.
  • the distance between the integrating sphere 33 and the inspection object S is too large, the radiation angle of the light L2 from the inspection object S (that is, the efficiency of taking the light L2 into the integrating sphere 33) becomes the inspection object S.
  • the inspection object S is a GaN semiconductor, for example, the alignment mark is not attached to the GaN semiconductor wafer before the semiconductor process, and it is difficult to guarantee the reproducibility of the position.
  • the focus map can be acquired together with the acquisition of PL data. By doing so, it is possible to use the focus map when acquiring the ODPL data and keep the distance between the integrating sphere 33 and the inspection object S constant at each coordinate.
  • the integrating sphere 33 is arranged in the X direction on the lower surface side of the XZ stage 32 in the switching unit 31. This makes it possible to arrange the integrating sphere 33 directly above the inspection object S when acquiring the ODPL data.
  • the ODPL data can be acquired without being restricted by the size of the inspection object S, unlike the 2 ⁇ arrangement in which the inspection object S is arranged inside the integrating sphere 33.
  • the processing unit 21 may have a high-resolution ODPL mapping data generation unit 24, as in the first embodiment.
  • the high-resolution ODPL mapping data generation unit 24 refers to the PL mapping data received from the PL mapping data generation unit 22 and the ODPL mapping data received from the ODPL mapping data generation unit 35, and the above equations (1) to High-resolution ODPL mapping data is generated by converting the PL mapping data using (3).
  • the inspection device 1B may include a beam source 36 for acquiring ODPL data in addition to the beam source 3 for acquiring PL data.
  • the emission surface of the beam L in the beam source 36 is arranged so as to face the X direction, for example, and is optically connected to the optical system 5.
  • the excitation light L3 emitted from the excitation light source 37 is guided to the integrating sphere 33 via an optical element 38 such as a mirror.
  • the excitation light source 37 may be, for example, either a coherent light source or an incoherent light source, similarly to the excitation light source 11.
  • the coherent light source examples include an excima laser (wavelength 193 nm), a YAG laser second harmonic (wavelength 532 nm), a YAG laser fourth harmonic (wavelength 266 nm), a semiconductor laser (for example, an InGaN semiconductor laser (wavelength 375 nm to 530 nm), red). (Semiconductor laser, infrared semiconductor laser) and the like can be used.
  • a mercury lamp wavelength 365 nm
  • an LED light source or the like can be used.
  • the excitation light L3 output from the excitation light source 37 may be either pulsed light or CW light.
  • a GaN semiconductor wafer is exemplified as the inspection object S, and the distribution of structural defects and the quantitative inspection of defects of the GaN semiconductor wafer by PL measurement and ODPL measurement are exemplified.
  • the conversion of can also be applied to multiphoton excitation PL measurements, time-resolved photoluminescence (TRPL) measurements.
  • the beam sources 3 and 36 are not limited to the excitation light sources 11 and 37, and may emit X-rays or electron beams. In this case, it can be applied to reflection measurement, transmission measurement, phase difference measurement, differential interference measurement, emission measurement (cathode luminescence measurement, etc.) by irradiating a beam including X-rays and electron beams, and ODPL with the same configuration. Correlation with mapping can be obtained.

Abstract

An inspection device 1A comprises: a stage 2 on which an inspection subject S is placed; a beam source 3 that generates a beam L applied to the inspection subject S; a photodetector 4 that detects light L2 generated at the inspection subject S by application of the beam L; an optical system 5 that guides the beam L to the inspection subject S on the stage 2 and also guides the light L2 generated at the inspection subject S to the photodetector 5; and a processing unit 21 that transforms unidirectional data regarding unidirectional light of the light L2 detected by the photodetector 4, on the basis of omnidirectional data regarding omnidirectional light generated from the inspection subject S.

Description

検査装置及び検査方法Inspection equipment and inspection method
　本開示は、検査装置及び検査方法に関する。 This disclosure relates to inspection equipment and inspection methods.
　例えば半導体ウェハなどの検査対象物に対する検査方法として、検査対象物から発生する一方位の光を測定する技術がある。当該技術としては、例えばフォトルミネッセンス測定（以下、ＰＬ測定）等の発光測定が知られている。発光測定は、検査対象物にビームを照射し、励起された電子が基底状態に戻る際に発生する光を測定する手法である。ＰＬ測定では、ビームとして光が用いられ、カソードルミネッセンス測定では、ビームとして電子線が用いられる。発光測定では、構造欠陥の分布を検出可能である一方、半導体ウェハの品質担保の観点からは、欠陥の定量化や再現性の向上が求められている。 For example, as an inspection method for an inspection object such as a semiconductor wafer, there is a technique for measuring one-sided light generated from the inspection object. As the technique, for example, luminescence measurement such as photoluminescence measurement (hereinafter referred to as PL measurement) is known. Luminescence measurement is a method of irradiating an object to be inspected with a beam and measuring the light generated when the excited electrons return to the ground state. In PL measurement, light is used as a beam, and in cathode luminescence measurement, an electron beam is used as a beam. While the distribution of structural defects can be detected by emission measurement, from the viewpoint of quality assurance of semiconductor wafers, it is required to quantify defects and improve reproducibility.
　検査対象物に対する別の検査方法として、検査対象物から発生する全方位の光を測定する技術がある。当該技術としては、全方位フォトルミネッセンス測定（以下、ＯＤＰＬ測定）が知られている（例えば非特許文献１参照）。ＯＤＰＬ測定は、積分球を用いて検査対象物に吸収された励起光のフォトン数及び全方位への発光フォトン数を測定する手法である。ＯＤＰＬ測定では、構造欠陥等を含む非輻射再結合に影響されるバンド端発光の発光量子効率を算出できるため、欠陥の定量化が可能となっている。 As another inspection method for the inspection target, there is a technique for measuring the omnidirectional light generated from the inspection target. As the technique, omnidirectional photoluminescence measurement (hereinafter referred to as ODPL measurement) is known (see, for example, Non-Patent Document 1). The ODPL measurement is a method of measuring the number of photons of excitation light absorbed by an object to be inspected and the number of emitted photons in all directions using an integrating sphere. In the ODPL measurement, the emission quantum efficiency of band-end emission affected by non-radiation recombination including structural defects can be calculated, so that defects can be quantified.
　発光測定を行う装置は、一般に広く普及している。しかしながら、欠陥の定量化や再現性の向上を目的として装置の検査機能を拡張しようとする場合、ＯＤＰＬ測定を行う装置のような別の装置を新規に導入する必要がある。この場合、コスト面の問題が生じるほか、装置間での検査対象物に対するビームの位置ずれやビーム特性の相違といったシステム由来の測定精度のばらつきが生じることが考えられる。そのため、このような問題を生じさせることなく、検査機能を簡便に拡張することが可能な技術が望まれていた。 Devices for measuring luminescence are widely used in general. However, if the inspection function of the device is to be expanded for the purpose of quantifying defects and improving reproducibility, it is necessary to newly introduce another device such as a device for performing ODPL measurement. In this case, in addition to the problem of cost, it is conceivable that the measurement accuracy due to the system may vary, such as the position shift of the beam with respect to the inspection object and the difference in the beam characteristics between the devices. Therefore, a technique capable of easily expanding the inspection function without causing such a problem has been desired.
　本開示は、上記課題の解決のためになされたものであり、検査機能を簡便に拡張することが可能な検査装置及び測定方法を提供することを目的とする。 The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide an inspection device and a measurement method capable of easily expanding the inspection function.
　本開示の一側面に係る検査装置は、検査対象物が載置されるステージと、検査対象物に照射するビームを生成するビーム源と、ビームの照射により検査対象物で発生する光を検出する光検出器と、ステージ上の検査対象物にビームを導くと共に、検査対象物で発生した光を光検出器に導く光学系と、検査対象物から発生する全方位の光に関する全方位データに基づいて、光検出器で検出された光のうちの一方位の光に関する一方位データの変換を行う処理部と、を備える。 The inspection apparatus according to one aspect of the present disclosure detects a stage on which an inspection object is placed, a beam source that generates a beam to irradiate the inspection object, and light generated by the inspection object by the beam irradiation. Based on the photodetector, the optical system that guides the beam to the inspection object on the stage and guides the light generated by the inspection object to the photodetector, and the omnidirectional data on the omnidirectional light generated from the inspection object. It also includes a processing unit that converts one-sided data regarding one-sided light among the lights detected by the photodetector.
　この検査装置では、検査対象物で発生した光を検出し、検出された光のうちの一方位の光に関する一方位データを、検査対象物から発生する全方位の光に関する全方位データに基づいて変換する。このように、全方位データを用いて一方位データを変換することで、一方位データを測定する装置とは別の装置を新規に導入することなく、一方位データとは別のデータを取得できる。したがって、コスト面の負担増や、装置間での検査対象物に対するビームの位置ずれやビーム特性の相違といったシステム由来の測定精度のばらつきの問題を回避しつつ、検査機能を簡便に拡張することが可能となる。 This inspection device detects the light generated in the inspection object, and the one-sided data regarding the one-sided light among the detected lights is based on the omnidirectional data regarding the omnidirectional light generated from the inspection object. Convert. In this way, by converting the one-sided data using the omnidirectional data, it is possible to acquire data different from the one-sided data without newly introducing a device different from the device for measuring the one-sided data. .. Therefore, it is possible to easily expand the inspection function while avoiding the problem of system-derived measurement accuracy variation such as increased cost burden, beam misalignment with respect to the inspection object between devices, and difference in beam characteristics. It will be possible.
　処理部は、一方位データに関する第１のマッピングデータを生成してもよい。これにより、検査対象物における一方位データの分布を取得でき、検査対象物の検査を好適に実施できる。 The processing unit may generate the first mapping data regarding the one-sided data. As a result, the distribution of the one-sided data in the inspection target can be obtained, and the inspection of the inspection target can be suitably performed.
　処理部は、全方位データに基づいて、第１のマッピングデータから全方位データに関する第２のマッピングデータを生成してもよい。これにより、検査対象物における全方位データの分布を取得でき、検査対象物の検査を好適に実施できる。また、第１のマッピングデータと全方位データとを組み合わせることで、全方位データの高分解能化が可能となる。 The processing unit may generate a second mapping data regarding the omnidirectional data from the first mapping data based on the omnidirectional data. As a result, the distribution of omnidirectional data in the inspection target can be acquired, and the inspection of the inspection target can be suitably performed. Further, by combining the first mapping data and the omnidirectional data, it is possible to increase the resolution of the omnidirectional data.
　処理部には、検査対象物についての全方位データが予め格納されていてもよい。この場合、検査に要する時間の短縮化が図られる。 Omnidirectional data about the inspection target may be stored in advance in the processing unit. In this case, the time required for the inspection can be shortened.
　光学系は、一方位データを取得する第１の光学系と、全方位データを取得する第２の光学系と、第１の光学系と第２の光学系とを切り替える切替部と、を有していてもよい。この場合、一方位データを測定する装置とは別の装置を新規に導入することなく、一方位データ及び全方位データの双方を取得できる。 The optical system has a first optical system for acquiring one-sided data, a second optical system for acquiring omnidirectional data, and a switching unit for switching between the first optical system and the second optical system. You may be doing it. In this case, both the one-sided data and the omnidirectional data can be acquired without newly introducing a device different from the device for measuring the one-sided data.
　ビーム源は、検査対象物を励起する励起ビームを生成してもよい。この場合、検査対象物に吸収された励起ビームの測定や、励起ビームの照射によって検査対象物で発生した光の測定に基づいて、検査機能を十分に拡張することが可能となる。 The beam source may generate an excitation beam that excites the object to be inspected. In this case, the inspection function can be sufficiently expanded based on the measurement of the excitation beam absorbed by the inspection object and the measurement of the light generated in the inspection object by the irradiation of the excitation beam.
　本開示の一側面に係る検査方法は、検査対象物にビームを照射する照射ステップと、検査対象物で発生する光を検出する光検出ステップと、光検出ステップで検出された光のうちの一方位の光に関する一方位データを取得する取得ステップと、検査対象物から発生する全方位の光に関する全方位データに基づいて、一方位データの変換を行う処理ステップと、を備える。 The inspection method according to one aspect of the present disclosure is one of an irradiation step of irradiating an inspection object with a beam, a light detection step of detecting light generated in the inspection object, and light detected in the light detection step. It includes an acquisition step of acquiring one-sided data regarding directional light, and a processing step of converting one-sided data based on omnidirectional data related to omnidirectional light generated from an inspection object.
　この検査方法では、検査対象物で発生した光を検出し、検出された光のうちの一方位の光に関する一方位データを、検査対象物から発生する全方位の光に関する全方位データに基づいて変換する。このように、全方位データを用いて一方位データを変換することで、一方位データを測定する装置とは別の装置を新規に導入することなく、一方位データとは別のデータを取得できる。したがって、コスト面の負担増や、装置間での検査対象物に対するビームの位置ずれやビーム特性の相違といったシステム由来の測定精度のばらつきの問題を回避しつつ、検査機能を簡便に拡張することが可能となる。 In this inspection method, the light generated in the inspection object is detected, and the one-sided data regarding the one-sided light among the detected lights is based on the omnidirectional data regarding the omnidirectional light generated from the inspection object. Convert. In this way, by converting the one-sided data using the omnidirectional data, it is possible to acquire data different from the one-sided data without newly introducing a device different from the device for measuring the one-sided data. .. Therefore, it is possible to easily expand the inspection function while avoiding the problem of system-derived measurement accuracy variation such as increased cost burden, beam misalignment with respect to the inspection object between devices, and difference in beam characteristics. It will be possible.
　処理ステップでは、一方位データに関する第１のマッピングデータを生成してもよい。これにより、検査対象物における一方位データの分布を取得でき、検査対象物の検査を好適に実施できる。 In the processing step, the first mapping data regarding the one-sided data may be generated. As a result, the distribution of the one-sided data in the inspection target can be acquired, and the inspection of the inspection target can be suitably performed.
　処理ステップでは、全方位データに基づいて、第１のマッピングデータから全方位データに関する第２のマッピングデータを生成してもよい。これにより、検査対象物における全方位データの分布を取得でき、検査対象物の検査を好適に実施できる。また、第１のマッピングデータと全方位データとを組み合わせることで、全方位データの高分解能化が可能となる。 In the processing step, the second mapping data related to the omnidirectional data may be generated from the first mapping data based on the omnidirectional data. As a result, the distribution of omnidirectional data in the inspection target can be acquired, and the inspection of the inspection target can be suitably performed. Further, by combining the first mapping data and the omnidirectional data, it is possible to increase the resolution of the omnidirectional data.
　処理ステップでは、予め取得した検査対象物についての全方位データを用いてもよい。この場合、検査に要する時間の短縮化が図られる。 In the processing step, omnidirectional data about the inspection target acquired in advance may be used. In this case, the time required for the inspection can be shortened.
　光検出ステップでは、一方位データを取得する第１の光学系と、全方位データを取得する第２の光学系とを切り替え、取得ステップでは、一方位データ及び全方位データを取得してもよい。この場合、一方位データを測定する装置とは別の装置を新規に導入することなく、一方位データ及び全方位データの双方を取得できる。 In the light detection step, the first optical system for acquiring unidirectional data and the second optical system for acquiring omnidirectional data may be switched, and in the acquisition step, unidirectional data and omnidirectional data may be acquired. .. In this case, both the one-sided data and the omnidirectional data can be acquired without newly introducing a device different from the device for measuring the one-sided data.
　照射ステップでは、検査対象物を励起する励起ビームを照射してもよい。この場合、検査対象物に吸収された励起ビームの測定や、励起ビームの照射によって検査対象物で発生した光の測定に基づいて、検査機能を十分に拡張することが可能となる。 In the irradiation step, an excitation beam that excites the object to be inspected may be irradiated. In this case, the inspection function can be sufficiently expanded based on the measurement of the excitation beam absorbed by the inspection object and the measurement of the light generated in the inspection object by the irradiation of the excitation beam.
　本開示によれば、検査機能を簡便に拡張することが可能となる。 According to the present disclosure, the inspection function can be easily expanded.
本開示の第１実施形態に係る検査装置の構成を示す概略図である。It is a schematic diagram which shows the structure of the inspection apparatus which concerns on 1st Embodiment of this disclosure. 図１に示した検査装置の処理部の構成を示すブロック図である。It is a block diagram which shows the structure of the processing part of the inspection apparatus shown in FIG. ＯＤＰＬマッピングデータの一例を示す図である。It is a figure which shows an example of ODPL mapping data. ＰＬマッピングデータの一例を示す図である。It is a figure which shows an example of PL mapping data. 高分解能ＯＤＰＬマッピングデータの一例を示す図である。It is a figure which shows an example of high-resolution ODPL mapping data. 図１に示した検査装置におけるＰＬマッピングデータ生成処理の一例を示すフローチャートである。It is a flowchart which shows an example of PL mapping data generation processing in the inspection apparatus shown in FIG. 図１に示した検査装置における高分解能ＯＤＰＬマッピングデータ生成処理の一例を示すフローチャートである。It is a flowchart which shows an example of the high-resolution ODPL mapping data generation processing in the inspection apparatus shown in FIG. 本開示の第２実施形態に係る検査装置の構成を示す概略図である。It is a schematic diagram which shows the structure of the inspection apparatus which concerns on 2nd Embodiment of this disclosure. 図８に示した検査装置における光学系切り替え後の状態を示す概略図である。It is a schematic diagram which shows the state after the optical system switching in the inspection apparatus shown in FIG. 図８に示した検査装置の処理部の構成を示すブロック図である。It is a block diagram which shows the structure of the processing part of the inspection apparatus shown in FIG. 図８に示した検査装置におけるＰＬマッピングデータ生成処理の一例を示すフローチャートである。It is a flowchart which shows an example of PL mapping data generation processing in the inspection apparatus shown in FIG. 図８に示した検査装置におけるＯＤＰＬマッピングデータ生成処理の一例を示すフローチャートである。It is a flowchart which shows an example of the ODPL mapping data generation processing in the inspection apparatus shown in FIG. 第２の光学系の変形例を示す概略図である。It is a schematic diagram which shows the modification of the 2nd optical system.
　以下、図面を参照しながら、本開示の一側面に係る検査装置及び検査方法の好適な実施形態について詳細に説明する。
［第１実施形態］ Hereinafter, preferred embodiments of the inspection apparatus and inspection method according to one aspect of the present disclosure will be described in detail with reference to the drawings.
[First Embodiment]
　図１は、本開示の第１実施形態に係る検査装置の構成を示す概略図である。同図に示す検査装置１Ａは、検査対象物Ｓの非破壊検査を行う装置である。本実施形態では、検査対象物Ｓとして、化合物半導体ウェハを例示する。より具体的には、検査対象物Ｓは、窒化ガリウム（ＧａＮ）半導体ウェハである。ＧａＮ半導体は、可視／紫外の発光デバイスのほか、高周波デバイス、パワーデバイスへの応用が期待される材料である。ＧａＮ半導体を用いたデバイスの特性は、貫通転位のような構造欠陥、点欠陥、微量不純物の混入によって大きく影響を受けることが知られている。検査装置１Ａは、デバイスの歩留まりを改善し、量産化を推進すべく、ＧａＮ半導体ウェハの構造欠陥の分布及び欠陥の定量性の双方を検査する装置として構成されている。 FIG. 1 is a schematic diagram showing the configuration of the inspection device according to the first embodiment of the present disclosure. The inspection device 1A shown in the figure is a device for performing non-destructive inspection of the inspection object S. In this embodiment, a compound semiconductor wafer is exemplified as the inspection object S. More specifically, the inspection object S is a gallium nitride (GaN) semiconductor wafer. GaN semiconductors are expected to be applied to high-frequency devices and power devices as well as visible / ultraviolet light emitting devices. It is known that the characteristics of devices using GaN semiconductors are greatly affected by structural defects such as through dislocations, point defects, and contamination with trace impurities. The inspection device 1A is configured as a device for inspecting both the distribution of structural defects and the quantification of defects of a GaN semiconductor wafer in order to improve the yield of the device and promote mass production.
　検査装置１Ａでは、ＧａＮ半導体ウェハの構造欠陥の分布及び欠陥の定量性の双方を検査するにあたり、検査対象物Ｓから発生する一方位の光に関する一方位データ、及び検査対象物Ｓから発生する全方位の光に関する全方位データを取得する。一方位データは、例えばフォトルミネッセンス測定（以下、ＰＬ測定）等の発光測定に基づくデータである。全方位データは、全方位フォトルミネッセンス測定（以下、ＯＤＰＬ測定）に基づくデータである。 In the inspection device 1A, when inspecting both the distribution of structural defects and the quantification of defects of the GaN semiconductor wafer, the one-sided data regarding the one-sided light generated from the inspection object S and all the one-sided data generated from the inspection object S are inspected. Get omnidirectional data about directional light. The one-sided data is data based on luminescence measurement such as photoluminescence measurement (hereinafter referred to as PL measurement). The omnidirectional data is data based on omnidirectional photoluminescence measurement (hereinafter referred to as ODPL measurement).
　発光測定は、検査対象物にビームを照射し、ビームによって励起された電子が基底状態に戻る際に発生する光を測定する手法である。ＰＬ測定では、ビームとして光が用いられ、カソードルミネッセンス測定では、ビームとして電子線が用いられる。発光測定では、検査対象物の構造欠陥の分布を検出可能である一方、半導体ウェハの品質担保の観点からは、欠陥の定量化や再現性の向上が求められている。 Luminescence measurement is a method of irradiating an object to be inspected with a beam and measuring the light generated when the electrons excited by the beam return to the ground state. In PL measurement, light is used as a beam, and in cathode luminescence measurement, an electron beam is used as a beam. While it is possible to detect the distribution of structural defects in the inspection object in the light emission measurement, from the viewpoint of quality assurance of the semiconductor wafer, it is required to quantify the defects and improve the reproducibility.
　ＯＤＰＬ測定は、積分球を用いて検査対象物に吸収された励起光のフォトン数及び全方位への発光フォトン数を測定する手法である。ＯＤＰＬ測定では、構造欠陥等を含む非輻射再結合に影響されるバンド端発光の発光量子効率（内部量子効率（ＩＱＥ）又は外部量子効率（ＥＱＥ））を算出できるため、欠陥の定量化が可能となる。内部量子効率（ＩＱＥ）は、検査対象物で発生した発光フォトン数と、検査対象物で吸収された励起光のフォトン数との割合である。外部量子効率（ＥＱＥ）は、検査対象物の外部に放出された発光フォトン数と、検査対象物で吸収された励起光のフォトン数との割合である。 ODPL measurement is a method of measuring the number of photons of excitation light absorbed by an object to be inspected and the number of emitted photons in all directions using an integrating sphere. In ODPL measurement, the emission quantum efficiency (internal quantum efficiency (IQE) or external quantum efficiency (EQE)) of band-end emission affected by non-radiative recombination including structural defects can be calculated, so defects can be quantified. Will be. Internal quantum efficiency (IQE) is the ratio of the number of emitted photons generated in the inspection object to the number of photons in the excitation light absorbed by the inspection object. External quantum efficiency (EQE) is the ratio of the number of emitted photons emitted to the outside of the inspection object to the number of photons of the excitation light absorbed by the inspection object.
　対物レンズを用いた場合のＰＬ測定の空間分解能は、数μｍ～数サブμｍ程度である。これに対し、ＯＤＰＬ測定の空間分解能は、数百μｍ～数十μｍ程度であり、ＰＬ測定の空間分解能に対して１桁～２桁程度低いものとなっている。これは、ＯＤＰＬ測定では、検査対象物に向かうビームを積分球に通す必要があり、焦点距離の長いレンズを要する結果、ビームサイズの小径化に光学的な制約が生じることに起因している。そこで、検査装置１Ａでは、全方位データ（ＯＤＰＬデータ）に基づいて一方位データ（ＰＬデータ）の変換を行うことにより、高分解能ＯＤＰＬデータを取得できるようになっている。これにより、検査装置１Ａでは、検査機能を簡便に拡張することが可能となっており、ＧａＮ半導体ウェハの構造欠陥の分布及び欠陥の定量性の双方を一つの装置内で高精度に検査することができる。 The spatial resolution of PL measurement when using an objective lens is about several μm to several sub μm. On the other hand, the spatial resolution of the ODPL measurement is about several hundred μm to several tens of μm, which is about one to two orders of magnitude lower than the spatial resolution of the PL measurement. This is because in the ODPL measurement, it is necessary to pass the beam toward the inspection object through the integrating sphere, which requires a lens having a long focal length, and as a result, there is an optical limitation in reducing the diameter of the beam size. Therefore, the inspection device 1A can acquire high-resolution ODPL data by converting the one-sided data (PL data) based on the omnidirectional data (ODPL data). As a result, the inspection function of the inspection device 1A can be easily expanded, and both the distribution of structural defects and the quantification of defects of the GaN semiconductor wafer can be inspected with high accuracy in one device. Can be done.
　検査装置１Ａは、図１に示すように、ステージ２と、ビーム源３と、光検出器４と、光学系５とを備えている。また、検査装置１Ａは、図２に示すように、処理部２１と、表示部２６とを備えている。 As shown in FIG. 1, the inspection device 1A includes a stage 2, a beam source 3, a photodetector 4, and an optical system 5. Further, as shown in FIG. 2, the inspection device 1A includes a processing unit 21 and a display unit 26.
　ステージ２は、検査対象物が載置されるサンプルステージ６と、サンプルステージ６をＸ方向に走査可能なＸステージ７と、サンプルステージ６をＹ方向に走査可能なＹステージ８とを有している。ここでは、Ｘ方向は、検査対象物Ｓの面内方向の一方向であり、Ｙ方向は、検査対象物Ｓの面内方向においてＹ方向に直交する方向である。Ｚ方向は、Ｘ方向及びＹ方向に直交する方向であり、検査対象物Ｓの厚さ方向に対応する。サンプルステージ６、Ｘステージ７、及びＹステージ８は、いずれもベースプレート９上に設置されている。 The stage 2 has a sample stage 6 on which an object to be inspected is placed, an X stage 7 capable of scanning the sample stage 6 in the X direction, and a Y stage 8 capable of scanning the sample stage 6 in the Y direction. There is. Here, the X direction is one direction in the in-plane direction of the inspection object S, and the Y direction is a direction orthogonal to the Y direction in the in-plane direction of the inspection object S. The Z direction is a direction orthogonal to the X direction and the Y direction, and corresponds to the thickness direction of the inspection object S. The sample stage 6, the X stage 7, and the Y stage 8 are all installed on the base plate 9.
　ビーム源３は、検査対象物Ｓに照射するビームＬを生成する部分である。ビーム源３におけるビームＬの出射面は、例えばＸ方向を向くように配置され、光学系５に対して光学的に接続されている。ビーム源３としては、例えば検査対象物Ｓを励起するための励起光Ｌ１を出力する励起光源１１を用いることができる。励起光源１１は、例えばコヒーレント光源及びインコヒーレント光源のいずれであってもよい。コヒーレント光源としては、例えばエキシマレーザ（波長１９３ｎｍ）、ＹＡＧレーザ第２高調波（波長５３２ｎｍ）、ＹＡＧレーザ第４高調波（波長２６６ｎｍ）、半導体レーザ（例えばＩｎＧａＮ半導体レーザ（波長３７５ｎｍ～５３０ｎｍ）、赤色半導体レーザ、赤外半導体レーザ）などを用いることができる。インコヒーレント光源としては、例えば水銀ランプ（波長３６５ｎｍ）、ＬＥＤ光源などを用いることができる。励起光源１１から出力される励起光Ｌ１は、パルス光及びＣＷ光のいずれであってもよい。 The beam source 3 is a portion that generates a beam L to irradiate the inspection object S. The emission surface of the beam L in the beam source 3 is arranged so as to face the X direction, for example, and is optically connected to the optical system 5. As the beam source 3, for example, an excitation light source 11 that outputs excitation light L1 for exciting the inspection object S can be used. The excitation light source 11 may be, for example, either a coherent light source or an incoherent light source. Examples of the coherent light source include an excima laser (wavelength 193 nm), a YAG laser second harmonic (wavelength 532 nm), a YAG laser fourth harmonic (wavelength 266 nm), a semiconductor laser (for example, an InGaN semiconductor laser (wavelength 375 nm to 530 nm), red). (Semiconductor laser, infrared semiconductor laser) and the like can be used. As the incoherent light source, for example, a mercury lamp (wavelength 365 nm), an LED light source, or the like can be used. The excitation light L1 output from the excitation light source 11 may be either pulse light or CW light.
　光検出器４は、ビームＬの照射により検査対象物Ｓで発生する光Ｌ２を検出する部分である。光検出器４の検出面は、例えばＺ方向においてステージ２側を向くように配置され、光学系５に対して光学的に接続されている。ここでは、光検出器４は、励起光Ｌ１の照射によって検査対象物Ｓで励起された電子が基底状態に戻る際に発生する光Ｌ２を検出する。光検出器４は、検出結果を示す信号を処理部２１（図２参照）に出力する。光検出器４としては、例えばＣＭＯＳ、ＣＣＤ、ＥＭ－ＣＣＤ、光電子増倍管、ＳｉＰＭ（ＭＰＰＣ）、ＡＰＤ（ＳＰＡＤ）、フォトダイオード（アレイ状のものも含む）などを用いることができる。 The photodetector 4 is a portion that detects the light L2 generated in the inspection object S by the irradiation of the beam L. The detection surface of the photodetector 4 is arranged so as to face the stage 2 side in the Z direction, for example, and is optically connected to the optical system 5. Here, the photodetector 4 detects the light L2 generated when the electrons excited by the inspection object S by the irradiation of the excitation light L1 return to the ground state. The photodetector 4 outputs a signal indicating the detection result to the processing unit 21 (see FIG. 2). As the photodetector 4, for example, CMOS, CCD, EM-CDCD, photomultiplier tube, SiPM (MPPC), APD (SPAD), photodiode (including array-shaped one) and the like can be used.
　光学系５は、ステージ２上の検査対象物Ｓにビーム源３からのビームＬを導くと共に、検査対象物Ｓで発生した光Ｌ２を光検出器４に導く部分である。より具体的には、光学系５は、対物レンズ１２と、フィルタホルダ１３とを含んで構成されている。対物レンズ１２は、Ｚ方向に走査可能なＺステージ１４に設けられている。フィルタホルダ１３は、第１のフィルタ１５と第２のフィルタ１６とを備えている。フィルタホルダ１３は、Ｘ方向にスライド自在に設けられており、第１のフィルタ１５及び第２のフィルタ１６の一方が光学系５の光路に配置される。 The optical system 5 is a portion that guides the beam L from the beam source 3 to the inspection object S on the stage 2 and guides the light L2 generated by the inspection object S to the photodetector 4. More specifically, the optical system 5 includes an objective lens 12 and a filter holder 13. The objective lens 12 is provided on the Z stage 14 that can scan in the Z direction. The filter holder 13 includes a first filter 15 and a second filter 16. The filter holder 13 is slidably provided in the X direction, and one of the first filter 15 and the second filter 16 is arranged in the optical path of the optical system 5.
　第１のフィルタ１５は、ＰＬ測定の際に用いられるフィルタである。第１のフィルタ１５が光学系５の光路に配置される場合、励起光源１１からの励起光Ｌ１の少なくとも一部を反射し、対物レンズ１２を通して検査対象物Ｓに導光する。第１のフィルタ１５は、励起光Ｌ１の照射によって検査対象物Ｓで発生する光Ｌ２の少なくとも一部を透過させ、光検出器４に導光する。 The first filter 15 is a filter used for PL measurement. When the first filter 15 is arranged in the optical path of the optical system 5, at least a part of the excitation light L1 from the excitation light source 11 is reflected and guided to the inspection object S through the objective lens 12. The first filter 15 transmits at least a part of the light L2 generated in the inspection object S by the irradiation of the excitation light L1 and guides the light to the photodetector 4.
　第２のフィルタ１６は、反射測定の際に用いられるフィルタである。反射測定は、検査対象物Ｓの表面における励起光Ｌ１の反射状態を調べることにより、異常点の抽出する測定である。第２のフィルタ１６が光学系５の光路に配置される場合、励起光源１１からの励起光Ｌ１の少なくとも一部を反射し、対物レンズ１２を通して検査対象物Ｓに導光する。第２のフィルタ１６は、検査対象物Ｓで反射した励起光Ｌ１の少なくとも一部を透過させ、光検出器４に導光する。対物レンズ１２の開口数ＮＡは、例えば０．５程度となっている。第２のフィルタ１６としては、例えばダイクロイックミラー、バンドパスフィルタ等が用いられる。 The second filter 16 is a filter used for reflection measurement. The reflection measurement is a measurement for extracting an abnormal point by examining the reflected state of the excited light L1 on the surface of the inspection object S. When the second filter 16 is arranged in the optical path of the optical system 5, at least a part of the excitation light L1 from the excitation light source 11 is reflected and guided to the inspection object S through the objective lens 12. The second filter 16 transmits at least a part of the excitation light L1 reflected by the inspection object S and guides the light to the photodetector 4. The numerical aperture NA of the objective lens 12 is, for example, about 0.5. As the second filter 16, for example, a dichroic mirror, a bandpass filter, or the like is used.
　処理部２１は、光検出器４から出力される検出信号に基づき、データ処理を行う部分である。処理部２１は、物理的には、ＲＡＭ、ＲＯＭ等のメモリ、及びＣＰＵ等のプロセッサ（演算回路）、通信インターフェイス、ハードディスク等の格納部を備えたコンピュータである。かかるコンピュータとしては、例えばパーソナルコンピュータ、クラウドサーバ、スマートデバイス（スマートフォン、タブレット端末など）などが挙げられる。処理部２１は、メモリに格納されるプログラムをＣＰＵで実行することにより、図２に示すように、ＰＬマッピングデータ生成部２２、反射マッピングデータ生成部２３、及び高分解能ＯＤＰＬマッピングデータ生成部２４として機能する。処理部２１は、ＯＤＰＬマッピングデータ格納部２５を有している。処理部２１は、モニタ等の表示部２６と情報通信可能に接続されている。 The processing unit 21 is a unit that performs data processing based on the detection signal output from the photodetector 4. The processing unit 21 is physically a computer including a memory such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, and a storage unit such as a hard disk. Examples of such a computer include a personal computer, a cloud server, a smart device (smartphone, tablet terminal, etc.) and the like. By executing the program stored in the memory on the CPU, the processing unit 21 serves as the PL mapping data generation unit 22, the reflection mapping data generation unit 23, and the high-resolution ODPL mapping data generation unit 24, as shown in FIG. Function. The processing unit 21 has an ODPL mapping data storage unit 25. The processing unit 21 is connected to a display unit 26 such as a monitor so that information can be communicated.
　ＰＬマッピングデータ生成部２２は、ＰＬデータ（一方位データ）に関するＰＬマッピングデータ（第１のマッピングデータ）を生成する部分である。ＰＬマッピングデータ生成部２２は、ＰＬ測定時における光検出器４の検出信号と、その測定座標とに基づいて、検査対象物ＳについてのＰＬマッピングデータを生成する。ＰＬマッピングデータ生成部２２は、生成したＰＬマッピングデータを高分解能ＯＤＰＬマッピングデータ生成部２４に出力する。 The PL mapping data generation unit 22 is a part that generates PL mapping data (first mapping data) related to PL data (one-sided data). The PL mapping data generation unit 22 generates PL mapping data for the inspection object S based on the detection signal of the photodetector 4 at the time of PL measurement and the measurement coordinates thereof. The PL mapping data generation unit 22 outputs the generated PL mapping data to the high-resolution ODPL mapping data generation unit 24.
　反射マッピングデータ生成部２３は、反射データに関するマッピングデータを生成する部分である。反射マッピングデータ生成部２３は、反射測定時における光検出器４の検出信号と、その測定座標とに基づいて、検査対象物Ｓについての反射マッピングデータを生成する。反射マッピングデータ生成部２３は、生成した反射マッピングデータを高分解能ＯＤＰＬマッピングデータ生成部２４に出力する。 The reflection mapping data generation unit 23 is a part that generates mapping data related to the reflection data. The reflection mapping data generation unit 23 generates reflection mapping data for the inspection object S based on the detection signal of the photodetector 4 at the time of reflection measurement and the measurement coordinates thereof. The reflection mapping data generation unit 23 outputs the generated reflection mapping data to the high-resolution ODPL mapping data generation unit 24.
　高分解能ＯＤＰＬマッピングデータ生成部２４は、ＯＤＰＬデータ（全方位データ）に基づいて、ＰＬマッピングデータ（第１のマッピングデータ）から高分解能ＯＤＰＬマッピングデータ（第２のマッピングデータ）を生成する部分である。本実施形態では、検査対象物ＳについてのＯＤＰＬマッピングデータがＯＤＰＬマッピングデータ格納部２５に予め格納されている。 The high-resolution ODPL mapping data generation unit 24 is a portion that generates high-resolution ODPL mapping data (second mapping data) from PL mapping data (first mapping data) based on ODPL data (omnidirectional data). .. In the present embodiment, the ODPL mapping data for the inspection object S is stored in advance in the ODPL mapping data storage unit 25.
　高分解能ＯＤＰＬマッピングデータ生成部２４は、ＰＬマッピングデータ生成部２２からＰＬマッピングデータを受け取ると、ＯＤＰＬマッピングデータ格納部２５に格納されているＯＤＰＬマッピングデータを参照し、当該ＯＤＰＬマッピングデータを用いてＰＬマッピングデータを高分解能ＯＤＰＬマッピングデータに変換する。高分解能ＯＤＰＬマッピングデータ生成部２４は、生成した高分解能ＯＤＰＬマッピングデータに基づく検査結果画像を表示部２６に出力する。高分解能ＯＤＰＬマッピングデータ生成部２４は、生成した高分解能ＯＤＰＬマッピングデータとＰＬマッピングデータとを重畳した画像を検査結果画像として表示部２６に出力してもよい。 When the high-resolution ODPL mapping data generation unit 24 receives the PL mapping data from the PL mapping data generation unit 22, the high-resolution ODPL mapping data generation unit 24 refers to the ODPL mapping data stored in the ODPL mapping data storage unit 25, and uses the ODPL mapping data to PL. Convert the mapping data to high resolution ODPL mapping data. The high-resolution ODPL mapping data generation unit 24 outputs an inspection result image based on the generated high-resolution ODPL mapping data to the display unit 26. The high-resolution ODPL mapping data generation unit 24 may output an image in which the generated high-resolution ODPL mapping data and the PL mapping data are superimposed to the display unit 26 as an inspection result image.
　ＯＤＰＬマッピングデータ格納部２５に予め格納されているＯＤＰＬマッピングデータは、例えば事前のＯＤＰＬ測定で得られたデータである。このデータは、検査対象物ＳがＧａＮ半導体ウェハである場合、例えば同一ロット内でドープ濃度や欠陥が同一であると想定されるＧａＮ半導体ウェハのカッティングサンプルに対して予めＯＤＰＬ測定を行うことによって取得することができる。 The ODPL mapping data stored in advance in the ODPL mapping data storage unit 25 is, for example, data obtained by prior ODPL measurement. This data is acquired when the inspection target S is a GaN semiconductor wafer, for example, by performing ODPL measurement in advance on a cutting sample of a GaN semiconductor wafer that is assumed to have the same doping concentration and defects in the same lot. can do.
　ＰＬマッピングデータの変換には、下記式（１）～（３）を用いることができる。下記式（１）～（３）において、ηＯＤＰＬ（ｘ０，ｙ０）は、検査対象物Ｓの座標（ｘ０，ｙ０）においてＯＤＰＬ測定で得られた発光量子効率（内部量子効率（ＩＱＥ）又は外部量子効率（ＥＱＥ））である。ＰＮｅｍＰＬ（ｘ，ｙ）は、検査対象物Ｓの座標（ｘ，ｙ）においてＰＬ測定で得られた発光フォトン数である。ＳｔａｒｔＷＬは、検査対象物Ｓの対象発光領域における最小波長である。ＥｎｄＷＬは、検査対象物Ｓの対象発光領域における最大波長である。Ｉ（λ，ｘ，ｙ）は、検査対象物Ｓの座標（ｘ，ｙ）においてＰＬ測定で得られた発光強度である。ＷＬ（λ）は、発光領域における波長であり、αは変換係数である。
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
 The following equations (1) to (3) can be used for the conversion of the PL mapping data. In the following equations (1) to (3), the η ODPL (x 0 , y 0 ) is the emission quantum efficiency (internal quantum efficiency (internal quantum efficiency (internal quantum efficiency (internal quantum efficiency)) obtained by the ODPL measurement at the coordinates (x 0 , y 0 ) of the inspection object S. IQE) or external quantum efficiency (EQE)). PN emPL (x, y) is the number of luminescent photons obtained by PL measurement at the coordinates (x, y) of the inspection object S. StartWL is the minimum wavelength in the target emission region of the inspection target S. EndWL is the maximum wavelength in the target emission region of the inspection target S. I (λ, x, y) is the emission intensity obtained by PL measurement at the coordinates (x, y) of the inspection object S. WL (λ) is the wavelength in the light emitting region, and α is the conversion coefficient.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
　上記式（１）～（３）は、ＯＤＰＬ測定時の検査対象物Ｓの各座標における発光量子効率をＰＬ測定時の検査対象物Ｓの各座標での発光フォトン数で除算した除算値を求めるものである。上記式（１）～（３）を用いることにより、検査対象物Ｓの各座標における内部量子効率（ＩＱＥ）又は外部量子効率（ＥＱＥ）の相対的な評価が可能となる。上記式（１）～（３）で求めた除算値では、ＰＬ測定時の分解能が維持されるため、ＯＤＰＬマッピングデータに対して高分解能化された高分解能ＯＤＰＬマッピングデータを生成することが可能となる。 The above equations (1) to (3) obtain a division value obtained by dividing the emission quantum efficiency at each coordinate of the inspection object S at the time of ODPL measurement by the number of emission photons at each coordinate of the inspection object S at the time of PL measurement. It is a thing. By using the above equations (1) to (3), it is possible to relatively evaluate the internal quantum efficiency (IQE) or the external quantum efficiency (EQE) at each coordinate of the inspection object S. Since the resolution at the time of PL measurement is maintained by the division values obtained by the above equations (1) to (3), it is possible to generate high-resolution ODPL mapping data with higher resolution than the ODPL mapping data. Become.
　検査対象物Ｓへの励起光Ｌ１の照射条件として、励起光Ｌ１の波長又はスポットサイズを確認でき、且つ励起光Ｌ１の放射照度が一定であることが必要となる。また、検査対象物Ｓへの励起光Ｌ１の入射角が一定であることが必要となる。ＰＬマッピングデータから高分解能ＯＤＰＬマッピングデータへの変換は、検査対象物Ｓでの励起光Ｌ１の吸収量が一定である領域に適用することが好ましい。励起光Ｌ１の吸収量の判断は、検査対象物Ｓの表面の研磨状態が一定であることの確認、若しくはＰＬ測定時の励起光Ｌ１の反射量が一定であることの確認よって行われる。 As the irradiation condition of the excitation light L1 to the inspection object S, it is necessary that the wavelength or the spot size of the excitation light L1 can be confirmed and the irradiance of the excitation light L1 is constant. Further, it is necessary that the angle of incidence of the excitation light L1 on the inspection object S is constant. The conversion from the PL mapping data to the high-resolution ODPL mapping data is preferably applied to a region where the absorption amount of the excitation light L1 in the inspection object S is constant. The determination of the absorption amount of the excitation light L1 is performed by confirming that the polished state of the surface of the inspection object S is constant, or confirming that the reflection amount of the excitation light L1 at the time of PL measurement is constant.
　本実施形態では、励起光Ｌ１の吸収量の判断は、後者のＰＬ測定時の励起光Ｌ１の反射量の測定によって行われる。すなわち、高分解能ＯＤＰＬマッピングデータ生成部２４は、反射マッピングデータ生成部２３から反射マッピングデータを受け取ると、当該反射マッピングデータに基づいて検査対象物Ｓの各座標における反射量を所定の閾値と比較する。高分解能ＯＤＰＬマッピングデータ生成部２４は、反射量が閾値を超えている座標若しくは閾値に満たない座標を異常点として抽出し、その座標についてのデータを検査結果画像から除外することができる。 In the present embodiment, the absorption amount of the excitation light L1 is determined by measuring the reflection amount of the excitation light L1 at the time of the latter PL measurement. That is, when the high-resolution ODPL mapping data generation unit 24 receives the reflection mapping data from the reflection mapping data generation unit 23, the high-resolution ODPL mapping data generation unit 24 compares the reflection amount at each coordinate of the inspection object S with a predetermined threshold value based on the reflection mapping data. .. The high-resolution ODPL mapping data generation unit 24 can extract coordinates whose reflection amount exceeds the threshold value or coordinates below the threshold value as abnormal points, and can exclude data about those coordinates from the inspection result image.
　以下、各マッピングデータについて例示する。図３は、ＯＤＰＬマッピングデータの一例を示す図である。ここでは、直径２インチのＧａＮ半導体ウェハを検査対象物とした。励起光のスポット径はφ１００μｍ、測定間隔は２ｍｍピッチとした。図３の例では、ＧａＮ半導体ウェハの各座標におけるＥＱＥの値がスケールによる色分けにてマッピングされている。図４は、同一サンプルに対するＰＬマッピングデータであり、図３における破線枠Ａ内を拡大して示している。 The following is an example of each mapping data. FIG. 3 is a diagram showing an example of ODPL mapping data. Here, a GaN semiconductor wafer having a diameter of 2 inches was used as an inspection target. The spot diameter of the excitation light was φ100 μm, and the measurement interval was 2 mm pitch. In the example of FIG. 3, the EQE values at each coordinate of the GaN semiconductor wafer are mapped by color coding by scale. FIG. 4 is PL mapping data for the same sample, and the inside of the broken line frame A in FIG. 3 is enlarged and shown.
　図４中の黒点部分は、ＧａＮ半導体ウェハの貫通転位に起因する発光強度の減少箇所であると考えられる。図３に示したＯＤＰＬマッピングデータを参照すると、破線枠Ａ内のＥＱＥは、０．３％と見積もられる。したがって、上記式（１）～（３）を用いてＰＬマッピングデータの変換を行うことにより、図５に示すように、高分解能ＯＤＰＬマッピングデータを取得することができる。図５に示す高分解能ＯＤＰＬマッピングデータによれば、ＯＤＰＬ測定（ＥＱＥ）による欠陥の定量化が可能となると共に、ＰＬ測定による構造欠陥の分布を確認することができる。 The black spot portion in FIG. 4 is considered to be a portion where the emission intensity is reduced due to the through dislocation of the GaN semiconductor wafer. With reference to the ODPL mapping data shown in FIG. 3, the EQE in the dashed line frame A is estimated to be 0.3%. Therefore, by converting the PL mapping data using the above equations (1) to (3), high-resolution ODPL mapping data can be acquired as shown in FIG. According to the high-resolution ODPL mapping data shown in FIG. 5, defects can be quantified by ODPL measurement (EQE), and the distribution of structural defects can be confirmed by PL measurement.
　次に、検査装置１Ａの動作について説明する。この検査装置１Ａでは、検査対象物Ｓの検査にあたり、ＰＬマッピングデータ生成処理及び高分解能ＯＤＰＬマッピングデータ生成処理がこの順に実行される。 Next, the operation of the inspection device 1A will be described. In the inspection device 1A, the PL mapping data generation process and the high-resolution ODPL mapping data generation process are executed in this order when inspecting the inspection object S.
　図６は、ＰＬマッピングデータ生成処理の一例を示すフローチャートである。同図に示すように、ＰＬマッピングデータ生成処理では、まず、検査対象物Ｓのサイズに合わせて測定座標（ｘ，ｙ）数ｎの設定がなされる（ステップＳ０１）。次に、ステージ２が駆動し、励起光Ｌ１の照射位置が検査対象物Ｓにおける測定点ｉに移動する（ステップＳ０２）。この際、光学系５の光路上には、第１のフィルタ１５が配置される。そして、検査対象物Ｓに励起光Ｌ１が照射され、測定点ｉにおけるＰＬ測定が実行される（ステップＳ０３）。 FIG. 6 is a flowchart showing an example of PL mapping data generation processing. As shown in the figure, in the PL mapping data generation process, first, the number n of measurement coordinates (x, y) is set according to the size of the inspection object S (step S01). Next, the stage 2 is driven, and the irradiation position of the excitation light L1 moves to the measurement point i in the inspection object S (step S02). At this time, the first filter 15 is arranged on the optical path of the optical system 5. Then, the excitation light L1 is irradiated to the inspection object S, and the PL measurement at the measurement point i is executed (step S03).
　測定点ｉでのＰＬ測定の実行後、フィルタの切り替えが行われる（ステップＳ０４）。すなわち、フィルタホルダ１３がＸ方向にスライドし、光学系５の光路上に第２のフィルタ１６が配置される。そして、検査対象物Ｓに励起光Ｌ１が照射され、測定点ｉにおける反射測定が実行される（ステップＳ０５）。ＰＬ測定及び反射測定を終えた後、測定点ｉがｎに達したか否かが判断される（ステップＳ０６）。測定点ｉがｎに達したと判断された場合、各座標でのＰＬ測定結果に基づくＰＬマッピングデータ、及び各座標での反射測定結果に基づく反射マッピングデータが生成され、ＰＬマッピングデータ生成処理が終了する。測定点ｉがｎに達していないと判断された場合、ステップＳ０２に戻り、励起光Ｌ１の照射位置を測定点（ｉ＋１）に移動させた後、ステップＳ０３～ステップＳ０６の処理が繰り返し実行される。 After executing the PL measurement at the measurement point i, the filter is switched (step S04). That is, the filter holder 13 slides in the X direction, and the second filter 16 is arranged on the optical path of the optical system 5. Then, the excitation light L1 is irradiated to the inspection object S, and the reflection measurement at the measurement point i is executed (step S05). After finishing the PL measurement and the reflection measurement, it is determined whether or not the measurement point i has reached n (step S06). When it is determined that the measurement point i has reached n, PL mapping data based on the PL measurement result at each coordinate and reflection mapping data based on the reflection measurement result at each coordinate are generated, and the PL mapping data generation process is performed. finish. If it is determined that the measurement point i has not reached n, the process returns to step S02, the irradiation position of the excitation light L1 is moved to the measurement point (i + 1), and then the processes of steps S03 to S06 are repeatedly executed. ..
　図７は、高分解能ＯＤＰＬマッピングデータ生成処理の一例を示すフローチャートである。同図に示すように、高分解能ＯＤＰＬマッピングデータ生成処理では、まず、ＰＬマッピングデータ生成処理で生成されたＰＬマッピングデータの参照が行われる（ステップＳ１１）。また、ＰＬマッピングデータ生成処理で生成されたＰＬマッピングデータの参照が行われる（ステップＳ１２）。ステップＳ１１及びステップＳ１２は、いずれを先に実行してもよい。次に、反射マッピングデータに基づいて、励起光Ｌ１の反射量と閾値との比較がなされ、反射量が閾値を外れた座標が異常点として抽出される（ステップＳ１３）。 FIG. 7 is a flowchart showing an example of high resolution ODPL mapping data generation processing. As shown in the figure, in the high-resolution ODPL mapping data generation process, first, the PL mapping data generated in the PL mapping data generation process is referred to (step S11). In addition, the PL mapping data generated in the PL mapping data generation process is referenced (step S12). Either step S11 or step S12 may be executed first. Next, based on the reflection mapping data, the reflection amount of the excitation light L1 is compared with the threshold value, and the coordinates where the reflection amount is out of the threshold value are extracted as abnormal points (step S13).
　異常点の抽出の後、ＯＤＰＬマッピングデータ格納部２５に格納されているＯＤＰＬマッピングデータの参照が行われる（ステップＳ１４）。このＯＤＰＬマッピングデータに基づいて、上記式（１）～（３）を用いたＰＬマッピングデータの変換が行われる（ステップＳ１５）。これにより、高分解能ＯＤＰＬマッピングデータが生成され（ステップＳ１６）、高分解能ＯＤＰＬマッピングデータ生成処理が終了する。 After extracting the abnormal points, the ODPL mapping data stored in the ODPL mapping data storage unit 25 is referred to (step S14). Based on this ODPL mapping data, conversion of PL mapping data using the above equations (1) to (3) is performed (step S15). As a result, high-resolution ODPL mapping data is generated (step S16), and the high-resolution ODPL mapping data generation process is completed.
　以上説明したように、検査装置１Ａでは、検査対象物Ｓで発生した光Ｌ２を検出し、検出された光Ｌ２のうちの一方位の光に関するＰＬデータ（一方位データ）を、検査対象物Ｓから発生する全方位の光に関するＯＤＰＬデータ（全方位データ）に基づいて変換する。このように、ＯＤＰＬデータを用いてＰＬデータを変換することで、ＰＬ測定装置とは別のＯＤＰＬ測定装置を新規に導入することなく、ＰＬデータとは別のデータを取得して検査対象物Ｓの検査を実施できる。したがって、コスト面の負担増や、装置間での検査対象物Ｓに対するビームＬの位置ずれやビーム特性の相違といったシステム由来の測定精度のばらつきの問題を回避しつつ、検査機能を簡便に拡張することができる。 As described above, the inspection device 1A detects the light L2 generated in the inspection target object S, and collects PL data (one-sided data) related to the one-order light of the detected light L2 in the inspection target object S. Converts based on ODPL data (omnidirectional data) related to omnidirectional light generated from. In this way, by converting the PL data using the ODPL data, data different from the PL data can be acquired and the inspection object S can be obtained without newly introducing an ODPL measuring device different from the PL measuring device. Can be inspected. Therefore, the inspection function can be easily expanded while avoiding the problems of system-derived measurement accuracy variation such as an increase in cost burden, a positional deviation of the beam L with respect to the inspection object S between the devices, and a difference in beam characteristics. be able to.
　検査装置１Ａでは、処理部２１は、ＰＬデータに関するＰＬマッピングデータ（第１のマッピングデータ）を生成する。これにより、検査対象物ＳにおけるＰＬデータの分布を取得でき、検査対象物Ｓの検査を好適に実施できる。 In the inspection device 1A, the processing unit 21 generates PL mapping data (first mapping data) related to PL data. As a result, the distribution of PL data in the inspection target S can be acquired, and the inspection of the inspection target S can be suitably performed.
　検査装置１Ａでは、処理部２１は、ＯＤＰＬデータに基づいて、ＰＬマッピングデータから全方位データに関する高分解能ＯＤＰＬマッピングデータ（第２のマッピングデータ）を生成する。これにより、検査対象物ＳにおけるＯＤＰＬデータの分布を取得でき、検査対象物Ｓの検査を好適に実施できる。また、ＰＬマッピングデータとＯＤＰＬデータとを組み合わせることで、ＯＤＰＬデータの高分解能化が可能となる。 In the inspection device 1A, the processing unit 21 generates high-resolution ODPL mapping data (second mapping data) related to omnidirectional data from the PL mapping data based on the ODPL data. As a result, the distribution of ODPL data in the inspection target S can be acquired, and the inspection of the inspection target S can be suitably performed. Further, by combining the PL mapping data and the ODPL data, it is possible to increase the resolution of the ODPL data.
　検査装置１Ａでは、処理部２１において、検査対象物ＳについてのＯＤＰＬデータが予め格納されている。これにより、検査対象物Ｓ毎にＯＤＰＬデータを取得する手間を省くことができ、検査に要する時間の短縮化が図られる。 In the inspection device 1A, the ODPL data for the inspection target S is stored in advance in the processing unit 21. As a result, it is possible to save the trouble of acquiring ODPL data for each inspection target object S, and it is possible to shorten the time required for inspection.
　検査装置１Ａでは、ビーム源３が検査対象物Ｓを励起する励起光Ｌ１を生成する。これにより、検査対象物Ｓに吸収された励起光Ｌ２の測定や、励起光Ｌ２の照射によって検査対象物Ｓで発生した光の測定に基づいて、検査機能を十分に拡張することが可能となる。
［第２実施形態］ In the inspection device 1A, the beam source 3 generates the excitation light L1 that excites the inspection object S. This makes it possible to sufficiently expand the inspection function based on the measurement of the excitation light L2 absorbed by the inspection object S and the measurement of the light generated in the inspection object S by the irradiation of the excitation light L2. ..
[Second Embodiment]
　図８は、本開示の第２実施形態に係る検査装置の構成を示す概略図である。同図に示すように、第２実施形態に係る検査装置１Ｂは、光学系５が、ＰＬデータ（一方位データ）を取得する第１の光学系５Ａ（図８参照）と、ＯＤＰＬデータ（全方位データ）を取得する第２の光学系５Ｂ（図９参照）と、第１の光学系５Ａと第２の光学系５Ｂとを切り替える切替部３１とを有している点で、第１実施形態と異なっている。 FIG. 8 is a schematic diagram showing the configuration of the inspection device according to the second embodiment of the present disclosure. As shown in the figure, in the inspection device 1B according to the second embodiment, the optical system 5 has the first optical system 5A (see FIG. 8) for acquiring PL data (one-sided data) and the ODPL data (all). The first embodiment is performed in that it has a second optical system 5B (see FIG. 9) for acquiring (orientation data) and a switching unit 31 for switching between the first optical system 5A and the second optical system 5B. It is different from the morphology.
　第１の光学系５Ａは、第１実施形態の検査装置１Ａの光学系５と同等の構成を有している。第２の光学系５Ｂは、対物レンズ１２に代えて積分球３３が光路上に配置される点で第１の光学系５Ａと相違している。本実施形態では、切替部３１は、Ｘ方向に走査可能なＸＺステージ３２によって構成されている。対物レンズ１２及び積分球３３は、ＸＺステージ３２の下面側にＸ方向に離間して設けられている。ＸＺステージ３２がＸ方向に走査することにより、対物レンズ１２及び積分球３３の一方が光学系５の光路に配置される。図８に示すように、対物レンズ１２が光学系５の光路に配置される場合、ＰＬデータを取得する第１の光学系５Ａが構成される。一方、図９に示すように、積分球３３が光学系５の光路に配置される場合、ＯＤＰＬデータを取得する第２の光学系５Ｂが構成される。 The first optical system 5A has the same configuration as the optical system 5 of the inspection device 1A of the first embodiment. The second optical system 5B differs from the first optical system 5A in that the integrating sphere 33 is arranged on the optical path instead of the objective lens 12. In the present embodiment, the switching unit 31 is configured by an XZ stage 32 that can scan in the X direction. The objective lens 12 and the integrating sphere 33 are provided on the lower surface side of the XZ stage 32 so as to be separated from each other in the X direction. As the XZ stage 32 scans in the X direction, one of the objective lens 12 and the integrating sphere 33 is arranged in the optical path of the optical system 5. As shown in FIG. 8, when the objective lens 12 is arranged in the optical path of the optical system 5, the first optical system 5A for acquiring PL data is configured. On the other hand, as shown in FIG. 9, when the integrating sphere 33 is arranged in the optical path of the optical system 5, a second optical system 5B for acquiring ODPL data is configured.
　図１０に示すように、積分球３３は、分光器３４に光学的に接続されている。また、処理部２１は、上述したＰＬマッピングデータ生成部２２と、ＯＤＰＬマッピングデータ生成部３５とを有している。励起光Ｌ１の照射によって検査対象物Ｓで生じた光Ｌ２は、積分球３３内で拡散反射を繰り返して空間的に積分された後、光ファイバＦを介して分光器３４に導光される。分光器３４は、検出結果に基づく結果信号をＯＤＰＬマッピングデータ生成部３５に出力する。 As shown in FIG. 10, the integrating sphere 33 is optically connected to the spectroscope 34. Further, the processing unit 21 has the PL mapping data generation unit 22 described above and the ODPL mapping data generation unit 35. The light L2 generated in the inspection object S by the irradiation of the excitation light L1 is spatially integrated by repeating diffuse reflection in the integrating sphere 33, and then guided to the spectroscope 34 via the optical fiber F. The spectroscope 34 outputs a result signal based on the detection result to the ODPL mapping data generation unit 35.
　ＯＤＰＬマッピングデータ生成部３５は、ＯＤＰＬデータ（全方位データ）に関するＯＤＰＬマッピングデータを生成する部分である。ＯＤＰＬマッピングデータ生成部３５は、ＯＤＰＬ測定時における分光器３４の検出信号と、その測定座標とに基づいて、検査対象物ＳについてのＯＤＰＬマッピングデータを生成する。ＯＤＰＬマッピングデータ生成部３５は、生成したＯＤＰＬマッピングデータを表示部２６に出力する。 The ODPL mapping data generation unit 35 is a part that generates ODPL mapping data related to ODPL data (omnidirectional data). The ODPL mapping data generation unit 35 generates ODPL mapping data for the inspection object S based on the detection signal of the spectroscope 34 at the time of ODPL measurement and the measurement coordinates thereof. The ODPL mapping data generation unit 35 outputs the generated ODPL mapping data to the display unit 26.
　次に、検査装置１Ｂの動作について説明する。検査装置１Ｂでは、検査対象物Ｓの検査にあたり、ＰＬマッピングデータ生成処理及びＯＤＰＬマッピングデータ生成処理が選択的に実行される。 Next, the operation of the inspection device 1B will be described. In the inspection device 1B, the PL mapping data generation process and the ODPL mapping data generation process are selectively executed in the inspection of the inspection object S.
　図１１は、ＰＬマッピングデータ生成処理の一例を示すフローチャートである。同図に示すように、ＰＬマッピングデータ生成処理では、まず、検査対象物Ｓのサイズに合わせて測定座標（ｘ，ｙ）数ｎの設定がなされる（ステップＳ２１）。次に、ＸＺステージ３２が駆動し、対物レンズ１２が光学系５の光路に配置される。これにより、ＰＬデータを取得するための第１の光学系５Ａがセットされる（ステップＳ２２）。第１の光学系５Ａのセットの後、ステージ２が駆動し、励起光Ｌ１の照射位置が検査対象物Ｓにおける測定点ｉに移動する（ステップＳ２３）。この際、第１の光学系５Ａの光路上には、第１のフィルタ１５が配置される。そして、検査対象物Ｓに励起光Ｌ１が照射され、測定点ｉにおけるＰＬ測定が実行される（ステップＳ２４）。 FIG. 11 is a flowchart showing an example of PL mapping data generation processing. As shown in the figure, in the PL mapping data generation process, first, the number n of measurement coordinates (x, y) is set according to the size of the inspection object S (step S21). Next, the XZ stage 32 is driven, and the objective lens 12 is arranged in the optical path of the optical system 5. As a result, the first optical system 5A for acquiring PL data is set (step S22). After setting the first optical system 5A, the stage 2 is driven and the irradiation position of the excitation light L1 moves to the measurement point i in the inspection object S (step S23). At this time, the first filter 15 is arranged on the optical path of the first optical system 5A. Then, the excitation light L1 is irradiated to the inspection object S, and the PL measurement at the measurement point i is executed (step S24).
　測定点ｉでのＰＬ測定を終えた後、測定点ｉがｎに達したか否かが判断される（ステップＳ２５）。測定点ｉがｎに達したと判断された場合、各座標でのＰＬ測定結果に基づくＰＬマッピングデータが生成され、ＰＬマッピングデータ生成処理が終了する。測定点ｉがｎに達していないと判断された場合、ステップＳ２３に戻り、励起光Ｌ１の照射位置を測定点（ｉ＋１）に移動させた後、ステップＳ２３～ステップＳ２５の処理が繰り返し実行される。 After completing the PL measurement at the measurement point i, it is determined whether or not the measurement point i has reached n (step S25). When it is determined that the measurement point i has reached n, PL mapping data based on the PL measurement result at each coordinate is generated, and the PL mapping data generation process ends. If it is determined that the measurement point i has not reached n, the process returns to step S23, the irradiation position of the excitation light L1 is moved to the measurement point (i + 1), and then the processes of steps S23 to S25 are repeatedly executed. ..
　図１２は、ＯＤＰＬマッピングデータ生成処理の一例を示すフローチャートである。同図に示すように、ＯＤＰＬマッピングデータ生成処理では、まず、検査対象物Ｓのサイズに合わせて測定座標（ｘ，ｙ）数ｎの設定がなされる（ステップＳ３１）。次に、ＸＺステージ３２が駆動し、積分球３３が光学系５の光路に配置される。これにより、ＯＤＰＬデータを取得するための第２の光学系５Ｂがセットされる（ステップＳ３２）。第２の光学系５Ｂのセットの後、ステージ２が駆動し、励起光Ｌ１の照射位置が検査対象物Ｓにおける測定点ｉに移動する（ステップＳ３３）。この際、第２の光学系５Ｂの光路上には、第１のフィルタ１５が配置される。そして、検査対象物Ｓに励起光Ｌ１が照射され、測定点ｉにおけるＯＤＰＬ測定が実行される（ステップＳ３４）。 FIG. 12 is a flowchart showing an example of the ODPL mapping data generation process. As shown in the figure, in the ODPL mapping data generation process, first, the number n of measurement coordinates (x, y) is set according to the size of the inspection object S (step S31). Next, the XZ stage 32 is driven, and the integrating sphere 33 is arranged in the optical path of the optical system 5. As a result, the second optical system 5B for acquiring ODPL data is set (step S32). After setting the second optical system 5B, the stage 2 is driven and the irradiation position of the excitation light L1 moves to the measurement point i in the inspection object S (step S33). At this time, the first filter 15 is arranged on the optical path of the second optical system 5B. Then, the excitation light L1 is irradiated to the inspection object S, and the ODPL measurement at the measurement point i is executed (step S34).
　測定点ｉでのＯＤＰＬ測定を終えた後、測定点ｉがｎに達したか否かが判断される（ステップＳ３５）。測定点ｉがｎに達したと判断された場合、各座標でのＯＤＰＬ測定結果に基づくＯＤＰＬマッピングデータが生成され、ＯＤＰＬマッピングデータ生成処理が終了する。測定点ｉがｎに達していないと判断された場合、ステップＳ３３に戻り、励起光Ｌ１の照射位置を測定点（ｉ＋１）に移動させた後、ステップＳ３３～ステップＳ３５の処理が繰り返し実行される。 After finishing the ODPL measurement at the measurement point i, it is determined whether or not the measurement point i has reached n (step S35). When it is determined that the measurement point i has reached n, ODPL mapping data based on the ODPL measurement result at each coordinate is generated, and the ODPL mapping data generation process ends. If it is determined that the measurement point i has not reached n, the process returns to step S33, the irradiation position of the excitation light L1 is moved to the measurement point (i + 1), and then the processes of steps S33 to S35 are repeatedly executed. ..
　以上のような検査装置１Ｂでは、光学系５が、ＰＬデータ（一方位データ）を取得する第１の光学系５Ａと、ＯＤＰＬデータ（全方位データ）を取得する第２の光学系５Ｂと、第１の光学系５Ａと第２の光学系５Ｂとを切り替える切替部３１とを有している。これにより、ＰＬデータを測定する装置とは別の装置を新規に導入することなく、ＰＬデータ及びＯＤＰＬデータの双方を取得できる。同一装置内でＰＬデータ及びＯＤＰＬデータの双方の取得機能を有することで、コスト面の問題を解消できるほか、装置間での検査対象物Ｓに対するビームＬの位置ずれやビーム特性の相違といったシステム由来の測定精度のばらつきが生じることも回避できる。 In the inspection device 1B as described above, the optical system 5 has a first optical system 5A for acquiring PL data (one-sided data), a second optical system 5B for acquiring ODPL data (omnidirectional data), and the like. It has a switching unit 31 for switching between the first optical system 5A and the second optical system 5B. As a result, both PL data and ODPL data can be acquired without newly introducing a device different from the device for measuring PL data. Having both PL data and ODPL data acquisition functions in the same device can solve cost problems, and is derived from the system such as the position shift of the beam L with respect to the inspection object S and the difference in beam characteristics between the devices. It is also possible to avoid variations in the measurement accuracy of.
　ＯＤＰＬ測定では、積分球３３と検査対象物Ｓとの間の距離が０になることが理想である。しかしながら、当該距離を０にすると、第２の光学系５Ｂをセットする際に検査対象物Ｓに積分球３３が接触し、検査対象物Ｓを傷付けてしまうことが考えられる。一方、積分球３３と検査対象物Ｓとの距離が離れすぎてしまうと、検査対象物Ｓからの光Ｌ２の放射角度（すなわち、積分球３３への光Ｌ２の取り込み効率）が検査対象物Ｓの位置によって不均一になってしまうおそれがある。検査対象物ＳがＧａＮ半導体である場合、例えば半導体プロセス前のＧａＮ半導体ウェハにはアライメントマークが付されておらず、位置の再現性の担保が難しいという事情もある。 In ODPL measurement, it is ideal that the distance between the integrating sphere 33 and the inspection object S is 0. However, when the distance is set to 0, it is conceivable that the integrating sphere 33 comes into contact with the inspection object S when the second optical system 5B is set, and the inspection object S is damaged. On the other hand, if the distance between the integrating sphere 33 and the inspection object S is too large, the radiation angle of the light L2 from the inspection object S (that is, the efficiency of taking the light L2 into the integrating sphere 33) becomes the inspection object S. There is a risk of unevenness depending on the position of. When the inspection object S is a GaN semiconductor, for example, the alignment mark is not attached to the GaN semiconductor wafer before the semiconductor process, and it is difficult to guarantee the reproducibility of the position.
　これに対し、同一装置内でＰＬデータ及びＯＤＰＬデータの双方の取得機能を有する場合、ＰＬデータの取得時にフォーカスマップを合わせて取得しておくことができる。こうすると、ＯＤＰＬデータの取得時にフォーカスマップを利用し、積分球３３と検査対象物Ｓとの間の距離を各座標において一定に保つことが可能となる。 On the other hand, if both PL data and ODPL data acquisition functions are provided in the same device, the focus map can be acquired together with the acquisition of PL data. By doing so, it is possible to use the focus map when acquiring the ODPL data and keep the distance between the integrating sphere 33 and the inspection object S constant at each coordinate.
　また、検査装置１Ｂでは、切替部３１において、ＸＺステージ３２の下面側にＸ方向に積分球３３が配置されている。これにより、ＯＤＰＬデータ取得の際、積分球３３を検査対象物Ｓの直上に配置するφ配置が可能となっている。φ配置の採用により、積分球３３の内部に検査対象物Ｓを配置する２π配置とは異なり、検査対象物Ｓのサイズの制限を受けることなくＯＤＰＬデータの取得を実施できる。 Further, in the inspection device 1B, the integrating sphere 33 is arranged in the X direction on the lower surface side of the XZ stage 32 in the switching unit 31. This makes it possible to arrange the integrating sphere 33 directly above the inspection object S when acquiring the ODPL data. By adopting the φ arrangement, the ODPL data can be acquired without being restricted by the size of the inspection object S, unlike the 2π arrangement in which the inspection object S is arranged inside the integrating sphere 33.
　検査装置１Ｂは、第１実施形態と同様に、処理部２１が高分解能ＯＤＰＬマッピングデータ生成部２４を有していてもよい。この場合、高分解能ＯＤＰＬマッピングデータ生成部２４は、ＰＬマッピングデータ生成部２２から受け取ったＰＬマッピングデータと、ＯＤＰＬマッピングデータ生成部３５から受け取ったＯＤＰＬマッピングデータとを参照し、上記式（１）～（３）を用いてＰＬマッピングデータを変換することにより高分解能ＯＤＰＬマッピングデータを生成する。 In the inspection device 1B, the processing unit 21 may have a high-resolution ODPL mapping data generation unit 24, as in the first embodiment. In this case, the high-resolution ODPL mapping data generation unit 24 refers to the PL mapping data received from the PL mapping data generation unit 22 and the ODPL mapping data received from the ODPL mapping data generation unit 35, and the above equations (1) to High-resolution ODPL mapping data is generated by converting the PL mapping data using (3).
　検査装置１Ｂは、図１３に示すように、ＰＬデータの取得のためのビーム源３とは別に、ＯＤＰＬデータの取得のためのビーム源３６を備えていてもよい。ビーム源３６におけるビームＬの出射面は、例えばＸ方向を向くように配置され、光学系５に対して光学的に接続されている。励起光源３７から出射した励起光Ｌ３は、ミラー等の光学素子３８を介して積分球３３に導光される。励起光源３７は、励起光源１１と同様に、例えばコヒーレント光源及びインコヒーレント光源のいずれであってもよい。コヒーレント光源としては、例えばエキシマレーザ（波長１９３ｎｍ）、ＹＡＧレーザ第２高調波（波長５３２ｎｍ）、ＹＡＧレーザ第４高調波（波長２６６ｎｍ）、半導体レーザ（例えばＩｎＧａＮ半導体レーザ（波長３７５ｎｍ～５３０ｎｍ）、赤色半導体レーザ、赤外半導体レーザ）などを用いることができる。インコヒーレント光源としては、例えば水銀ランプ（波長３６５ｎｍ）、ＬＥＤ光源などを用いることができる。励起光源３７から出力される励起光Ｌ３は、パルス光及びＣＷ光のいずれであってもよい。 As shown in FIG. 13, the inspection device 1B may include a beam source 36 for acquiring ODPL data in addition to the beam source 3 for acquiring PL data. The emission surface of the beam L in the beam source 36 is arranged so as to face the X direction, for example, and is optically connected to the optical system 5. The excitation light L3 emitted from the excitation light source 37 is guided to the integrating sphere 33 via an optical element 38 such as a mirror. The excitation light source 37 may be, for example, either a coherent light source or an incoherent light source, similarly to the excitation light source 11. Examples of the coherent light source include an excima laser (wavelength 193 nm), a YAG laser second harmonic (wavelength 532 nm), a YAG laser fourth harmonic (wavelength 266 nm), a semiconductor laser (for example, an InGaN semiconductor laser (wavelength 375 nm to 530 nm), red). (Semiconductor laser, infrared semiconductor laser) and the like can be used. As the incoherent light source, for example, a mercury lamp (wavelength 365 nm), an LED light source, or the like can be used. The excitation light L3 output from the excitation light source 37 may be either pulsed light or CW light.
　このようなビーム源３６を採用する場合、ＯＤＰＬデータの取得時の励起光Ｌ３のスポットサイズの調整や励起光源３７の選択が容易なものとなる。また、測定座標をオフセットすることで、切替部３１による第１の光学系５Ａ及び第２の光学系５Ｂの切り替えを行うことなく、ＰＬデータの取得及びＯＤＰＬデータの取得を行うことができる。
［変形例］ When such a beam source 36 is adopted, it becomes easy to adjust the spot size of the excitation light L3 and select the excitation light source 37 at the time of acquiring the ODPL data. Further, by offsetting the measurement coordinates, it is possible to acquire PL data and ODPL data without switching between the first optical system 5A and the second optical system 5B by the switching unit 31.
[Modification example]
　本開示は、上記実施形態に限られるものではない。例えば上記実施形態では、検査対象物ＳとしてＧａＮ半導体ウェハを例示し、ＰＬ測定及びＯＤＰＬ測定によるＧａＮ半導体ウェハの構造欠陥の分布及び欠陥の定量性の検査を例示したが、本開示における一方位データの変換は、多光子励起ＰＬ測定、時間分解フォトルミネセンス（ＴＲＰＬ）測定に適用することもできる。 The present disclosure is not limited to the above embodiment. For example, in the above embodiment, a GaN semiconductor wafer is exemplified as the inspection object S, and the distribution of structural defects and the quantitative inspection of defects of the GaN semiconductor wafer by PL measurement and ODPL measurement are exemplified. The conversion of can also be applied to multiphoton excitation PL measurements, time-resolved photoluminescence (TRPL) measurements.
　ビーム源３，３６は、励起光源１１，３７に限られず、Ｘ線や電子線を出射するものであってもよい。この場合、Ｘ線や電子線も含めたビームの照射による反射測定、透過測定、位相差測定、微分干渉測定、発光測定（カソードルミネッセンス測定等）への適用も可能となり、同様の構成にてＯＤＰＬマッピングとの相関を得ることができる。 The beam sources 3 and 36 are not limited to the excitation light sources 11 and 37, and may emit X-rays or electron beams. In this case, it can be applied to reflection measurement, transmission measurement, phase difference measurement, differential interference measurement, emission measurement (cathode luminescence measurement, etc.) by irradiating a beam including X-rays and electron beams, and ODPL with the same configuration. Correlation with mapping can be obtained.
　１Ａ，１Ｂ…検査装置、２…ステージ、３…ビーム源、４…光検出器、５…光学系、５Ａ…第１の光学系、５Ｂ…第２の光学系、２１…処理部、３１…切替部、Ｌ…ビーム、Ｌ２…光、Ｓ…検査対象物。 1A, 1B ... Inspection device, 2 ... Stage, 3 ... Beam source, 4 ... Photodetector, 5 ... Optical system, 5A ... First optical system, 5B ... Second optical system, 21 ... Processing unit, 31 ... Switching unit, L ... beam, L2 ... light, S ... inspection target.

Claims (12)

  1. 　検査対象物が載置されるステージと、
    　前記検査対象物に照射するビームを生成するビーム源と、
    　前記ビームの照射により前記検査対象物で発生する光を検出する光検出器と、
    　前記ステージ上の前記検査対象物に前記ビームを導くと共に、前記検査対象物で発生した前記光を前記光検出器に導く光学系と、
    　前記検査対象物から発生する全方位の光に関する全方位データに基づいて、前記光検出器で検出された前記光のうちの一方位の光に関する一方位データの変換を行う処理部と、を備える検査装置。     The stage on which the object to be inspected is placed and
    A beam source that generates a beam to irradiate the object to be inspected,
    A photodetector that detects the light generated by the inspection object by irradiating the beam, and
    An optical system that guides the beam to the inspection object on the stage and guides the light generated by the inspection object to the photodetector.
    A processing unit that converts one-sided data regarding one-sided light among the said light detected by the photodetector based on omnidirectional data related to omnidirectional light generated from the inspection object. Inspection device.
  2. 　前記処理部は、前記一方位データに関する第１のマッピングデータを生成する請求項１記載の検査装置。 The inspection device according to claim 1, wherein the processing unit generates a first mapping data relating to the one-sided data.
  3. 　前記処理部は、前記全方位データに基づいて、前記第１のマッピングデータから前記全方位データに関する第２のマッピングデータを生成する請求項２記載の検査装置。 The inspection device according to claim 2, wherein the processing unit generates a second mapping data related to the omnidirectional data from the first mapping data based on the omnidirectional data.
  4. 　前記処理部には、前記検査対象物についての前記全方位データが予め格納されている請求項１～３のいずれか一項記載の検査装置。 The inspection device according to any one of claims 1 to 3, wherein the processing unit stores the omnidirectional data for the inspection object in advance.
  5. 　前記光学系は、前記一方位データを取得する第１の光学系と、前記全方位データを取得する第２の光学系と、前記第１の光学系と前記第２の光学系とを切り替える切替部と、を有している請求項１～３のいずれか一項記載の検査装置。 The optical system switches between a first optical system for acquiring the one-sided data, a second optical system for acquiring the omnidirectional data, and the first optical system and the second optical system. The inspection device according to any one of claims 1 to 3, which has a unit and a unit.
  6. 　前記ビーム源は、前記検査対象物を励起する励起ビームを生成する請求項１～５のいずれか一項記載の検査装置。 The inspection device according to any one of claims 1 to 5, wherein the beam source generates an excitation beam that excites the inspection object.
  7. 　検査対象物にビームを照射する照射ステップと、
    　前記検査対象物で発生する光を検出する光検出ステップと、
    　前記光検出ステップで検出された前記光のうちの一方位の光に関する一方位データを取得する取得ステップと、
    　前記検査対象物から発生する全方位の光に関する全方位データに基づいて、前記一方位データの変換を行う処理ステップと、を備える検査方法。     The irradiation step of irradiating the inspection object with a beam and
    A photodetection step that detects the light generated by the inspection object,
    The acquisition step of acquiring the one-sided data regarding the one-sided light of the said light detected in the light detection step, and the acquisition step.
    An inspection method comprising a processing step of converting the one-sided data based on omnidirectional data relating to omnidirectional light generated from the inspection object.
  8. 　前記処理ステップでは、前記一方位データに関する第１のマッピングデータを生成する請求項７記載の検査方法。 The inspection method according to claim 7, wherein in the processing step, the first mapping data relating to the one-sided data is generated.
  9. 　前記処理ステップでは、前記全方位データに基づいて、前記第１のマッピングデータから前記全方位データに関する第２のマッピングデータを生成する請求項８記載の検査方法。 The inspection method according to claim 8, wherein in the processing step, a second mapping data relating to the omnidirectional data is generated from the first mapping data based on the omnidirectional data.
  10. 　前記処理ステップでは、予め取得した前記検査対象物についての前記全方位データを用いる請求項７～９のいずれか一項記載の検査方法。 The inspection method according to any one of claims 7 to 9, which uses the omnidirectional data for the inspection target acquired in advance in the processing step.
  11. 　前記光検出ステップでは、前記一方位データを取得する第１の光学系と、前記全方位データを取得する第２の光学系とを切り替え、
    　前記取得ステップでは、前記一方位データ及び前記全方位データを取得する請求項７～９のいずれか一項記載の検査方法。     In the light detection step, the first optical system for acquiring the one-sided data and the second optical system for acquiring the omnidirectional data are switched.
    The inspection method according to any one of claims 7 to 9, wherein in the acquisition step, the one-sided data and the omnidirectional data are acquired.
  12. 　前記照射ステップでは、検査対象物を励起する励起ビームを照射する請求項７～１１のいずれか一項記載の検査方法。 The inspection method according to any one of claims 7 to 11, wherein in the irradiation step, an excitation beam that excites an inspection object is irradiated.
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