JP2014192444A - Inspection device and inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique of performing an inspection regarding generation, movement, and recombination of a photoexcited carrier in a portion where pulse light for inspection hardly reaches.SOLUTION: An inspection device 100 inspects a solar battery panel 90 that is one kind of photo device. The inspection device 100 includes: an irradiation part 12 for irradiating a light reception surface 9FS of the solar battery panel 90 with pulse light (pulse light LP11 for inspection) emitted from a femtosecond laser 121; a detection part 13 for detecting an electromagnetic wave pulse LT1 generated from the solar battery panel 90 in response to the irradiation with the pulse light LP11 for inspection; and a continuous light irradiation part 14 for irradiating a part of a back surface 9BS on an opposite side of the solar battery panel 90 with continuous light CW, the irradiated part of the back surface 9BS corresponding to a part of the light reception surface 9FS irradiated with the pulse light LP11 for inspection.

Description

  The present invention relates to a technique for inspecting a photo device in a non-contact manner.

  In a manufacturing process of a solar cell that is one type of photo device, an inspection apparatus that measures the electrical characteristics of the solar cell by applying a so-called four-terminal measurement method is used. More specifically, a current measuring probe pin and a voltage measuring probe pin are applied to the collecting electrodes provided on the light receiving surface and the back surface of the solar cell. In this state, the voltage applied to the solar cell is changed while the simulated sunlight is irradiated, and the relationship between the current and voltage is measured. Thereby, the IV characteristic of a solar cell is measured (for example, patent document 1).

  However, in the case of a conventional solar cell inspection apparatus, it is necessary to directly contact a probe pin for current measurement or voltage measurement with a collecting electrode. For this reason, there is a problem that the probe pin is rubbed off, for example, the plating of the probe pin is peeled off. Moreover, since the probe pin is brought into contact with the solar cell, the solar cell element may be damaged during the inspection.

  Therefore, the applicants of the present application have proposed an inspection method in which the probe pin is not brought into contact (Patent Document 2). Specifically, photoexcited carriers (free electrons and holes) are generated by irradiating a photo device with pulse light for inspection emitted from a femtosecond laser. This photoexcited carrier is accelerated by an internal electric field existing in a depletion layer or the like of the photo device, whereby a pulse current is generated and an electromagnetic wave is generated. Thus, by irradiating the irradiation photo device with pulsed light, an electromagnetic wave corresponding to the characteristics of the photoexcited carrier generation region is generated. Therefore, by analyzing the generated electromagnetic wave, it is possible to inspect the characteristics of the photo device (such as the depletion layer formation status).

JP 2010-182969 A JP2013-019861A

  By the way, photo devices such as solar cells are devices that use minority carriers. For example, in the case of a solar cell, it is important to efficiently extract electrons generated by light irradiation to the outside through an electrode. For example, in the case of a general crystalline silicon-based solar cell, most of the device is a p-type semiconductor layer. For this reason, it is important that not only the electrons near the n-type semiconductor layer on the light-receiving surface side or the depletion layer but also electrons generated in the p-type semiconductor layer reach the depletion layer without recombination by diffusion. It becomes. For this reason, a technique for inspecting the generation and recombination of electrons in the p-type semiconductor layer is required.

  However, as in Patent Document 2, it is usually difficult to make the pulsed light for inspection reach the opposite side only by irradiating the light-receiving surface with the pulsed light for inspection. That is, it is difficult to inspect the generation, movement, and recombination of photoexcited carriers in a portion where the pulse light for inspection hardly reaches (for example, the portion of the p-type semiconductor layer in the crystalline silicon solar cell). It was. Such a situation also holds true for photo devices other than solar cell panels.

  An object of the present invention is to provide a technique for inspecting the generation, movement, and recombination of photoexcited carriers in a portion of a photo device where pulse light for inspection hardly reaches.

  In order to solve the above-described problem, a first aspect is an inspection apparatus that inspects a photo device, and irradiates one light receiving surface of both surfaces of the photo device with pulsed light emitted from a femtosecond laser. An irradiation unit, a detection unit that detects an electromagnetic wave generated from the photo device in response to the irradiation of the pulsed light, and a portion of the light receiving surface that is irradiated with the pulsed light, opposite to the light receiving surface A continuous light irradiating unit that irradiates the back surface with continuous light.

  Moreover, the 2nd aspect is further provided with the irradiation condition change part which changes at least 1 among the irradiation diameter, intensity | strength, and wavelength of the said continuous light in the inspection apparatus which concerns on a 1st aspect.

  According to a third aspect, in the inspection apparatus according to the first or second aspect, the continuous light includes light having a plurality of different wavelengths.

  According to a fourth aspect, in the inspection apparatus according to the third aspect, the photo device is a solar cell, and the continuous light includes pseudo-sunlight.

  According to a fifth aspect, in the inspection apparatus according to the first or second aspect, the continuous light is a single-wavelength laser light.

  According to a sixth aspect, the inspection apparatus according to any one of the first to fifth aspects further includes a reverse bias voltage application unit that applies a voltage that causes the photo device to be in a reverse bias state.

  A seventh aspect is an inspection method for inspecting a photo device, wherein (a) a step of irradiating a light receiving surface of the photo device with pulsed light emitted from a femtosecond laser; and (b) the pulse A step of detecting electromagnetic waves generated from the photo device in response to light irradiation, and (c) the light receiving surface corresponding to a portion of the light receiving surface irradiated with the pulsed light in the step (a). And a step of irradiating the back surface portion on the opposite side with continuous light.

  According to the first to seventh aspects, photoexcited carriers can be generated in a portion where pulse light for inspection does not reach by being irradiated with continuous light. When the state of the internal electric field is changed by the generated photoexcited carrier, the electromagnetic wave generated by the inspection pulse light is changed. In other words, by detecting electromagnetic waves, it is possible to perform inspections related to generation, movement, and recombination of photoexcited carriers in a portion where pulsed light hardly reaches.

  According to the inspection apparatus which concerns on a 2nd aspect, the range which the electromotive force by continuous light generate | occur | produces can be changed by changing the irradiation diameter of continuous light. Further, the magnitude of the electromotive force generated can be arbitrarily changed by changing the light intensity. Moreover, the length by which continuous light enters the photo device can be changed by changing the wavelength.

  According to the 3rd aspect, a photo device can be test | inspected in the state exposed to the continuous light of a some wavelength.

  According to the 4th aspect, the solar cell in an actual use state can be test | inspected because a solar cell is irradiated with pseudo-sunlight.

  According to the fifth aspect, the characteristics depending on the wavelength of the photo device can be inspected.

  According to the sixth aspect, by setting the reverse bias state, an internal electric field such as a depletion layer is strengthened, so that the intensity of the generated electromagnetic wave can be strengthened. Thereby, the detection sensitivity of electromagnetic waves can be improved.

1 is a schematic configuration diagram of an inspection apparatus according to a first embodiment. It is a schematic block diagram of the irradiation part and detection part which concern on 1st Embodiment. It is a schematic sectional drawing of a solar cell panel. It is a top view when a solar cell panel is seen from the light-receiving surface side. It is a top view when a solar cell panel is seen from the back side. It is a flowchart of the 1st inspection. It is a top view which shows typically the part in which the continuous light is irradiated in a solar cell panel. It is a figure which shows the time waveform of the electromagnetic wave pulse decompress | restored by the time waveform decompression | restoration part. It is a figure which shows the spectrum distribution of an electromagnetic wave pulse. It is a figure which shows the time waveform of an electromagnetic wave pulse. It is a flowchart of the 2nd inspection. It is a figure which shows an example of an electric field strength distribution image. It is a schematic block diagram of the irradiation part and detection part of the inspection apparatus which concern on 2nd Embodiment. It is a schematic block diagram of the irradiation part and detection part of the inspection apparatus which concern on 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example embodying the present invention, and is not an example of limiting the technical scope of the present invention.

<1. First Embodiment>
<1.1. Configuration and Function>
FIG. 1 is a schematic configuration diagram of an inspection apparatus 100 according to the first embodiment. FIG. 2 is a schematic configuration diagram of the irradiation unit 12 and the detection unit 13 according to the first embodiment.

  As shown in FIG. 1, the inspection apparatus 100 includes a stage 11, an irradiation unit 12, a detection unit 13, a continuous light irradiation unit 14, a motor 15, a control unit 16, a monitor 17, and an operation input unit 18. The inspection apparatus 100 is configured to inspect a solar cell panel 90 that is a substrate on which a photo device is formed.

  When pulsed light emitted from a femtosecond laser is applied to a photo device such as the solar cell panel 90, an electromagnetic wave mainly including a terahertz wave (frequency is 0.1 to 30 THz) is generated from the photo device. This electromagnetic wave is considered to be generated based on the following principle. In other words, photoexcited carriers are generated in the photo device by irradiation with pulsed light having energy exceeding the band gap. The generated photoexcited carriers are accelerated by an internal electric field (built-in electric field) generated in a depletion layer or a metal semiconductor interface of the photo device, thereby generating a current. At this time, when the irradiation light is pulsed light, a time-varying pulsed current is generated, and therefore electromagnetic waves are generated according to Maxwell's equation.

  Here, the electromagnetic wave generated from the photo device is radiated according to the characteristics of the photoexcited carrier generation region such as a depletion layer. For this reason, the characteristics of the photoexcited carrier generation region can be inspected by detecting the emitted electromagnetic wave. Based on such a principle, the inspection apparatus 100 is configured to detect an electromagnetic wave pulse generated from the solar cell panel 90 in response to irradiation with pulse light having a predetermined wavelength.

  Note that the sample to be inspected by the inspection apparatus 100 is not limited to the solar cell panel 90, and any inspection target of the inspection apparatus 100 can be used as long as it includes a photo device that converts light including visible light into current. Can be a thing. Specific examples of the photo device other than the solar cell panel 90 include image sensors such as a CMOS sensor and a CCD sensor. Some image sensors are known in which a light receiving element is formed on the back side of a substrate on which a photo device is formed in use. Even if it is such a board | substrate, if it installs in the test | inspection apparatus 100 by making the main surface of the light-receiving side in a use condition into a light-receiving surface, electromagnetic waves can be detected favorably.

  The stage 11 fixes the solar cell panel 90 on the stage 11 by fixing means (not shown). As the fixing means, a sandwiching tool that sandwiches the solar cell panel 90, an adhesive sheet that adheres to the solar cell panel 90 and the stage 11, or a device that uses an adsorption hole formed on the surface of the stage 11 can be considered. Other fixing means may be employed. In the present embodiment, the stage 11 is arranged such that the irradiation unit 12 emits pulsed light to the light receiving surface 9FS side of the solar cell panel 90 and the detector 132 detects the electromagnetic wave pulse radiated to the light receiving surface side 9FS. The solar cell panel 90 is held. As shown in FIG. 2, in the inspection apparatus 100, continuous light CW is irradiated from the back surface 9 BS side of the solar cell panel 90. For this reason, the stage 11 is configured to transmit the continuous light CW. Specifically, an opening for transmitting the continuous light CW is formed in the stage 11. Alternatively, the stage 11 is made of a transparent material that does not shield the continuous light CW.

  As shown in FIG. 2, the irradiation unit 12 includes a femtosecond laser 121. The femtosecond laser 121 emits linearly polarized pulsed light having a wavelength of 360 nm (nanometers) to 1 μm (micrometers), a period of several kHz to several hundreds of MHz, and a pulse width of about 10 to 150 femtoseconds. Can be adopted.

  The pulsed light LP1 emitted from the femtosecond laser 121 is divided into two by the beam splitter B1. One of the divided pulse lights (hereinafter referred to as inspection pulse light LP11) is applied to the solar cell panel 90. At this time, the irradiation unit 12 performs irradiation of the inspection pulse light LP11 from the light receiving surface 9FS side. In addition, the inspection pulse light LP11 is applied to the solar cell panel 90 so that the optical axis of the inspection pulse light LP11 is obliquely incident on the light receiving surface 9FS of the solar cell panel 90. In the example shown in FIG. 2, the incident angle of the inspection pulse light LP11 is 45 degrees, but this incident angle can be appropriately changed within a range from 0 degrees to 90 degrees.

  FIG. 3 is a schematic cross-sectional view of the solar cell panel 90. FIG. 4 is a plan view of the solar cell panel 90 when viewed from the light receiving surface 9FS side. Furthermore, FIG. 5 is a plan view when the solar cell panel 90 is viewed from the back surface 9BS side. As shown in FIG. 3, the solar cell panel 90 has a laminated structure, and in order from the bottom, a grid-like back electrode 92 formed of aluminum or the like, a p-type silicon layer 93, and n-type silicon. The layer 94, the antireflection film 95, and a grid-shaped light receiving surface electrode 96 formed of aluminum or the like are included.

  The junction between the p-type silicon layer 93 and the n-type silicon layer 94 is a pn junction 97 where a depletion layer is formed. When this portion is irradiated with pulsed light, the generated photoexcited carriers are accelerated by the internal electric field, and as a result, electromagnetic waves are generated. The generated electromagnetic wave is radiated to the outside and is observed by the detector 132 as an electromagnetic wave pulse LT1.

  The solar cell panel 90 may be other than crystalline silicon (such as amorphous silicon). In general, the band gap (for example, 1.75 eV to 1.8 eV) of an amorphous silicon solar cell is larger than the band gap (for example, 1.2 eV) of a crystalline silicon solar cell. Therefore, in the case of an amorphous silicon solar cell, an electromagnetic wave including a terahertz wave can be generated satisfactorily from the amorphous silicon solar cell by setting the wavelength of the pulsed light emitted from the femtosecond laser to, for example, 700 μm or less. it can. In the same principle, other semiconductor solar cells (for example, compound systems (III-V group, CIGS system, CdTe system, etc.) and organic systems (such as dye-sensitized solar cells or organic thin film solar cells)) are also terahertz. It is possible to generate electromagnetic waves including waves satisfactorily.

  The antireflection film 95 is made of silicon oxide, silicon nitride, titanium oxide, or the like. In the solar cell panel 90, the main surface on which the light receiving surface electrode 96 is provided among the main surfaces on which the collecting electrodes (the light receiving surface electrode 96 and the back surface electrode 92) are provided is the light receiving surface 9FS. ing. That is, the solar cell panel 90 is designed to generate power by receiving light from the light receiving surface 9FS side. The light receiving surface electrode 96 may be a transparent electrode instead of an aluminum electrode in order to improve daylighting.

  The light receiving surface 9FS of the solar cell panel 90 has a required texture structure in order to suppress light reflection loss. Specifically, unevenness of several μm to several tens of μm formed by anisotropic etching or the like, or a V-shaped groove by a mechanical method is formed. Thus, the light receiving surface 9FS of the solar cell panel 90 is generally formed so as to be able to take light as efficiently as possible. Therefore, the light applied to the solar cell panel 90 is likely to reach the pn junction 97. In the case of the solar cell panel 90, light having a wavelength of 1 μm or less, which is a visible light wavelength region, can easily reach the pn junction 97.

  In addition, as will be described later, in this embodiment, continuous light CW is irradiated from the solar cell panel 9BS side. More specifically, the continuous light CW is irradiated to the portion irradiated with the inspection pulse light LP11 and the portion on the back surface 9BS side that overlaps in the front and back direction.

  Returning to FIG. 2, the other pulse light split by the beam splitter B <b> 1 enters the detector 132 through the delay unit 131 and the mirror as the detection pulse light LP <b> 12. Further, electromagnetic waves generated in response to the irradiation of the inspection pulse light LP11 that is pulsed light are collected by the parabolic mirrors M1 and M2 and enter the detector 132.

  The detector 132 is composed of a photoconductive switch or the like. When the detection pulsed light LP12 is irradiated to the detector 132 in a state where the electromagnetic wave generated from the solar cell panel 90 is incident on the detector 132, a current corresponding to the electric field strength of the electromagnetic wave pulse is instantaneously applied to the detector 132. Occurs. The current corresponding to the electric field strength is converted into a digital quantity via an I / V conversion circuit, an A / D conversion circuit, or the like. In this way, the detection unit 13 detects the electric field strength of the electromagnetic wave pulse generated from the solar cell panel 90 in response to the irradiation with the detection pulse light LP12. In this embodiment, a photoconductive switch is used for the detector 132, but other elements such as a nonlinear optical crystal may be used. It is also conceivable to detect electromagnetic waves using a Schottky barrier diode instead of a photoconductive switch.

  Note that by providing a polarizing element that polarizes the electromagnetic wave pulse LT1, an electromagnetic wave polarized in a specific direction of the emitted electromagnetic wave pulse LT1 may be detected by the detector 132. In this case, as the photoconductive switch, a spiral type photoconductive switch having a small polarization dependency is suitable as the detector 132.

  The delay unit 131 is an optical element for continuously changing the arrival time of the detection pulsed light LP12 from the beam splitter B1 to the detector 132. The delay unit 131 is fixed to a moving stage (not shown) that moves in the incident direction of the detection pulsed light LP12. The delay unit 131 includes a folding mirror 10M that folds the detection pulse light LP12 in the incident direction. The delay unit 131 drives the moving stage based on the control of the control unit 16, thereby moving the folding mirror 10M and precisely changing the optical path length of the detection pulsed light LP12. In this way, the delay unit 131 changes the time difference between the time when the electromagnetic wave pulse reaches the detection unit 13 and the time when the detection pulsed light LP12 reaches the detection unit 13. Timing for detecting the electric field intensity of the electromagnetic wave pulse LT1 in the detection unit 13 (detector 132) by changing the optical distance (optical path length) of the optical path (second optical path) of the detection pulse light LP12 by the delay unit 131. (Detection timing or sampling timing) can be advanced or delayed.

  In addition, it is also conceivable to change the time difference between the arrival times of the electromagnetic wave pulse LT1 and the detection pulse light LP12 to the detection unit 13 according to other modes. For example, a delay unit 131 may be provided on the optical path (first optical path) of the inspection pulse light LP11 so that the optical path length can be changed. Also in this case, the time for the electromagnetic wave pulse LT1 to reach the detector 132 and the time for the detection pulsed light LP12 to reach the detector 132 can be relatively shifted. Therefore, the detection timing of the electric field intensity of the electromagnetic wave pulse LT1 in the detector 132 can be delayed. It is also conceivable to use the electro-optic effect. That is, an electro-optic element whose refractive index changes by changing the applied voltage is used as the delay element. Specifically, an electro-optic element disclosed in Japanese Patent Application Laid-Open No. 2009-175127 can be used.

  As shown in FIG. 2, the solar cell panel 90 is connected with a reverse bias voltage application circuit 99 (reverse bias voltage application unit) that applies a reverse bias voltage between the back electrode 92 and the light receiving surface electrode 96 at the time of inspection. Has been. By applying a reverse bias voltage between the electrodes, the depletion layer formed at the pn junction 97 is enlarged, and the internal electric field is increased. Thereby, the mobility of the photoexcited carrier generated according to the irradiation of the inspection pulse light LP11 can be increased. Therefore, since the electric field strength of the electromagnetic wave pulse LT1 detected by the detector 132 can be increased, the detection sensitivity of the electromagnetic wave pulse LT1 in the detection unit 13 can be improved. Note that the reverse bias voltage application circuit 99 may be omitted.

  The continuous light irradiation unit 14 irradiates the solar cell panel 90 with the continuous light CW. The type of continuous light CW emitted from the continuous light irradiation unit 14 is appropriately selected according to the inspection purpose, and is not particularly limited. Specifically, it simulates sunlight or sunlight. Includes multiple wavelengths such as pseudo-sunlight, light with a relatively wide wavelength distribution such as incandescent lamps, and light with wavelengths corresponding to the three primary colors of RGB (400 nm, 600 nm, 800 nm, etc.) such as LED lighting and fluorescent lamps It is considered to be light. The continuous light CW may be, for example, light having a single wavelength selected from ultraviolet rays to near infrared rays.

  The continuous light irradiation part 14 is comprised according to the wavelength of the light used for a test | inspection. Specifically, the continuous light irradiation unit 14 is configured by, for example, a semiconductor laser, an LED, a halogen lamp, a xenon lamp, or a combination thereof. Further, a wavelength tunable laser may be used as the continuous light irradiation unit 14. As the wavelength tunable laser, for example, a distributed feedback (DFB) laser that can change the wavelength of the emitted laser beam substantially continuously (for example, every 2 nm) by temperature control can be used.

  The solar cell panel 90 is a device that handles minority carriers, and it is important how to efficiently extract electrons excited by light. In the case of a crystalline silicon solar cell, most of the device is composed of a p-type silicon layer 93 as shown in FIG. For this reason, it is important that not only electrons generated in the vicinity of the n-type silicon layer 94 or the pn junction 97 on the surface but also electrons generated in the p-type semiconductor reach the depletion layer without recombination. It is. Generally, the minority carrier diffusion length is reduced by improving the quality of the crystal by reducing the disorder of the arrangement of crystal atoms in the p-type silicon layer 93 or by reducing impurities as much as possible. The idea is to make it as long as possible.

  In this embodiment, in order to observe the dynamics from the generation of electrons to recombination in the p-type silicon layer 93, the back surface 9BS of the solar cell panel 90 is irradiated with continuous light CW. The continuous light CW enters the inside of the p-type silicon layer 93 by irradiating the continuous light CW not on the light receiving surface 9FS side of the solar cell panel 90 but on the back surface 9BS side. Thereby, electrons can be generated inside the p-type silicon layer 93.

  A light absorption coefficient α (cm−1) is known as a parameter that affects the performance of the solar cell. When light is irradiated on the solar cell, the light penetration length L when the light penetrates into the solar cell is expressed by the following equation using the light absorption coefficient α.

  L = 1 / α (Expression 1)

  For example, when the solar cell is crystalline silicon, the light penetration length L is about 100 μm (α = about 100 cm−1) when the wavelength of irradiated light is 1 μm, and the light penetration length L is about 10 μm when the wavelength is 800 nm. (Α = about 1000 cm −1) Further, in the case of 500 nm, the light penetration length L is about 1 μm (α = about 10000 cm −1).

  That is, in the case of crystalline silicon, visible light having a wavelength of 400 nm to 800 nm is absorbed within about 10 μm from the surface. Therefore, in this embodiment, when measuring a deeper portion of the solar cell panel 90 (that is, a portion closer to the light receiving surface 9BS), a continuous light CW having a wavelength of 1 μm or more may be used.

  In the inspection apparatus 100, a state in which photoexcited carriers are generated (a state in which an electromotive force is generated) can be created in the p-type silicon layer 93 by irradiating the continuous light CW from the back surface 9BS side. Then, due to the diffusion of the generated electrons, an electromotive force is generated, and the internal electric field of the depletion layer changes. The change in the internal electric field is detected as a change in the electromagnetic wave pulse LT1 emitted when the inspection pulse light LP11 is irradiated. That is, by observing the change of the electromagnetic wave pulse LT1, it is possible to inspect the diffusion characteristics of the photoexcited carriers in the portion opposite to the inspection pulse light LP11.

  For example, when the solar cell panel 90 is irradiated with pseudo-sunlight, a state of being exposed to sunlight outdoors can be reproduced. By analyzing the electromagnetic wave pulse LT1 generated in this state, it is possible to detect structural defects that may cause a problem when the solar cell panel 90 is used, or to evaluate the performance of the solar cell panel 90. Moreover, the characteristic of the solar cell panel 90 depending on the wavelength can be inspected by irradiating the continuous light CW limited to a specific wavelength.

  The continuous light irradiation unit 14 includes an irradiation condition changing unit 141. The irradiation condition changing unit 141 changes the spot diameter of the continuous light CW that is simultaneously irradiated to the solar cell panel 90. By changing the range in which the continuous light CW is irradiated at once by the irradiation condition changing unit 141, the range of the region where the electromotive force is generated can be arbitrarily changed.

  For example, when the beam diameter (irradiation diameter) of the inspection pulse light LP11 is 50 μm, if the beam diameter (irradiation diameter) of the continuous light CW is 50 μm or more, the peripheral portion of the region irradiated with the inspection pulse light LP11 Also, the state where an electromotive force is generated can be obtained. Here, the photoexcited carriers generated by the irradiation with the inspection pulse light LP11 are highly likely to be affected by the peripheral portion. Therefore, in order to inspect the solar cell panel 90 in a use state, it is desirable that the continuous light CW is irradiated also on the peripheral portion. Moreover, the continuous light CW does not necessarily have to be irradiated locally in a spot shape, and for example, the entire solar cell panel 90 may be irradiated simultaneously.

  Further, the irradiation condition changing unit 141 changes the light intensity of the continuous light CW. By changing the light intensity of the continuous light CW applied to the solar cell panel 90, the magnitude of the generated electromotive force can be arbitrarily changed. Thereby, the test | inspection of the solar cell panel 90 according to an electric power generation state is realizable. Note that, as a means for changing the intensity of the continuous light CW, for example, a light-shielding filter may be used, but is not limited thereto. Of course, the light intensity of the continuous light CW output from the continuous light irradiation unit 14 may be changed directly.

  Further, the irradiation condition changing unit 141 changes the function of changing the wavelength of the continuous light CW. Specifically, for example, when the irradiation condition changing unit 141 includes a filter, only a specific wavelength can be transmitted. Alternatively, a plurality of light sources that emit different wavelengths are prepared in advance, and the irradiation condition changing unit 141 guides the continuous light CW emitted from a specific light source among the plurality of light sources to the solar cell panel 90. Also good.

  The irradiation condition changing unit 141 is configured to change the irradiation diameter, the intensity, and the wavelength as described above, but may be configured to change at least one of these.

  The motor 15 drives an XY table (not shown) that moves the stage in a two-dimensional plane. The motor 15 drives the XY table to move the solar cell panel 90 held on the stage 11 relative to the irradiation unit 12. The inspection apparatus 100 can move the solar cell panel 90 to an arbitrary position within the two-dimensional plane by the motor 15. The inspection apparatus 100 can irradiate the continuous light CW and the inspection pulse light LP11 over a wide range of the solar cell panel 90 by the motor 15. Note that the operator may be able to manually move the stage 11. Moreover, you may provide the moving means which moves the irradiation part 12 and the continuous light irradiation part 14 within a two-dimensional plane while moving the solar cell panel 90 or moving the solar cell panel 90. Furthermore, the solar cell panel 90 may be scanned with the inspection pulse light LP11 by providing a galvanometer mirror, a polygon mirror, or the like that changes the optical path of the inspection pulse light LP11.

  The control unit 16 has a configuration as a general computer including a CPU, a RAM, an auxiliary storage device (for example, a hard disk) (not shown), and the like. As shown in FIG. 1, the control unit 16 is connected to the irradiation unit 12, the detection unit 13, the continuous light irradiation unit 14, and the motor 15, and controls these operations. Specifically, the control unit 16 receives data related to the electric field strength of the electromagnetic wave pulse LT1 from the detector 132. Further, the control unit 16 controls the movement of a moving stage (not shown) that moves the delay unit 131, or the delay unit 131 such as the moving distance of the folding mirror 10M from a linear scale or the like provided on the moving stage. Or receive data related to the location.

  The control unit 16 is connected to the time waveform restoration unit 21, the spectrum analysis unit 23, and the image generation unit 25, and causes these units to perform various arithmetic processes. The time waveform restoration unit 21, the spectrum analysis unit 23, and the image generation unit 25 may be realized in software by a CPU (not shown) operating according to a program, or some or all of these functions are dedicated circuits. May be implemented in hardware.

  The time waveform restoration unit 21 constructs a time waveform of the electromagnetic wave pulse LT1 based on the electric field strength detected by the detection unit 13 (detector 132) for the electromagnetic wave pulse LT1 generated in the solar cell panel 90. Specifically, by moving the delay unit 131, the electric field intensity of the electromagnetic wave pulse LT1 is detected at a plurality of mutually different detection timings, whereby the time waveform is restored. This restoration method will be described later.

  The spectrum analysis unit 23 performs spectrum analysis based on the time waveform of the electromagnetic wave pulse LT1. Specifically, the spectrum analysis unit 23 acquires an amplitude intensity spectrum related to the frequency by performing a Fourier transform on the time waveform of the electromagnetic wave pulse LT1.

  The image generation unit 25 generates an image visualizing the electric field intensity distribution of the generated electromagnetic wave pulse LT1 with respect to the inspection target region on the solar cell panel 90 (part or all of the solar cell panel 90). Specifically, with respect to the image representing the light receiving surface 9FS of the solar cell panel 90, a portion corresponding to each measurement point is painted with a color corresponding to the electric field strength of the actually measured electromagnetic wave pulse LT1. Thereby, an electric field strength distribution image is generated.

  As shown in FIG. 1, a monitor 17 and an operation input unit 18 are connected to the control unit 16. The monitor 17 is a display device such as a liquid crystal display, and presents various image information to the operator. On the monitor 17, an image of the light receiving surface 9FS of the solar battery panel 90 photographed by the camera, an electric field intensity distribution image generated by the image generation unit 25, and the like are displayed. In addition, a GUI screen for executing inspection condition settings (setting of an inspection area in the solar battery panel 90, setting of irradiation intensity or irradiation range of the continuous light CW, etc.) may be displayed on the monitor 17.

<1.2. Photo device inspection>
Next, the flow of inspection of the solar cell panel 90 that is a photo device will be described. The inspection apparatus 100 according to the present embodiment is configured to be able to perform two types of inspections (first inspection and second inspection).

  The first inspection is an inspection based on the time waveform of the electromagnetic wave pulse LT1. In the first inspection, a specific position (interesting position) to be inspected on the solar cell panel 90 is irradiated with the continuous light CW and the inspection pulse light LP11 that is pulsed light. Then, the time waveform of the electromagnetic wave pulse LT1 generated in response to the irradiation with the inspection pulse light LP11 is restored. Further, spectrum analysis is performed on the restored time waveform.

  The second inspection is an inspection for acquiring the electric field intensity distribution of the electromagnetic wave pulse LT1 generated in response to the irradiation with the inspection pulse light LP11. In the second inspection, the continuous light CW and the inspection pulse light LP11 are irradiated to each point on the solar cell panel 90. Then, the electric field strength of the electromagnetic wave pulse LT1 generated at each point is totaled. In the following, the first inspection will be described first, and then the second inspection will be described. In the following description, each operation of the inspection apparatus 100 is controlled by the control unit 16 unless otherwise specified.

<First inspection>
FIG. 6 is a flowchart of the first inspection. The flow of the first inspection shown in FIG. 6 is an example. Therefore, some processes may be executed in parallel, or the execution order of some processes may be appropriately changed.

  First, the solar cell panel 90 to be inspected is fixed to the stage 11 (FIG. 6: Step S10). Note that the solar cell panel 90 may be carried into the stage 11 by an operator, or the solar cell panel 90 may be carried into the stage 11 by a transfer device (not shown). At this time, as described above, the solar cell panel 90 is installed such that the inspection pulse light LP11 is irradiated toward the light receiving surface 9FS of the solar cell panel 90.

  When the solar cell panel 90 is fixed to the stage 11, the inspection apparatus 100 moves the solar cell panel 90 according to the position of interest (FIG. 6: step S11). This interest position is based on information that the operator inputs through the operation input unit 18 as data (coordinate data) related to the position on the solar cell panel 90 to be inspected in advance. Based on this coordinate data, the control unit 16 drives the motor 15 to move the stage 11 so that the position of interest is irradiated with the inspection pulse light LP11. The operator himself / herself may move the stage 11 manually to move the solar cell panel 90 in accordance with the position of interest.

  Next, the irradiation conditions for the continuous light CW are set (FIG. 6: Step S12). Specifically, the setting of the irradiation range of the continuous light CW, the intensity of the continuous light CW, and the like are set. Moreover, when the continuous light irradiation part 14 is comprised so that the continuous light CW of a different wavelength can be irradiated, the wavelength of the continuous light CW radiate | emitted at this step is set. Further, the irradiation condition changing unit 141 appropriately changes the light shielding region so that the irradiation diameter of the continuous light CW is set. Then, based on the set irradiation condition of the continuous light CW, the continuous light irradiation unit 14 starts the irradiation of the continuous light CW (FIG. 6: Step S13).

  Next, the inspection apparatus 100 irradiates the inspection pulse light LP11 toward the inspection position of the solar cell panel 90 (FIG. 6: Step S14). FIG. 7 is a plan view schematically showing a portion of the solar cell panel 90 that is irradiated with the continuous light CW. The continuous light CW corresponds to the portion of the back surface 9BS opposite to the light receiving surface 9FS corresponding to the portion of the light receiving surface 9FS (pulse light irradiated portion 83) irradiated with the inspection pulse light LP11 in the solar cell panel 90 (continuous). The light irradiation portion 81) is irradiated. Here, “continuous light irradiation portion 81” corresponds to “pulse light irradiation portion 83 pulse light irradiation portion 83”. As shown in FIG. 7, “continuous light irradiation portion 81” corresponds to solar cell panel 90. Means that it overlaps with the “pulsed light irradiation portion 83” in a direction perpendicular to the light receiving surface 9FS. In other words, when viewed from the back surface 9BS, the continuous light irradiation portion 81 and the pulsed light irradiation portion 83 overlap each other. Thus, by setting the continuous light irradiation portion 81, the electrons generated by the irradiation of the inspection pulse light LP11 are easily affected by the movement of the electrons generated by the irradiation of the continuous light CW. That is, the electromagnetic wave pulse LT1 that is affected by the electromotive force generated by the continuous light CW is easily generated. Therefore, it is possible to inspect generation and recombination of photoexcited carriers in a portion where the inspection pulse light LP11 cannot reach.

  Further, the inspection apparatus 100 detects the electric field strength of the electromagnetic wave pulse LT1 generated in response to the irradiation of the inspection pulse light LP11 (FIG. 6: Step S15). When the electric field strength of the electromagnetic wave pulse LT1 is detected in step S15, the control unit 16 controls the delay unit 131 to delay the timing at which the detection pulsed light LP12 arrives at the detector 132. Thereby, the electric field strength of the electromagnetic wave pulse LT1 is detected at a plurality of different detection timings. When the solar cell panel 90 is irradiated with the test pulse light LP11, the reverse bias voltage application circuit 99 may be driven to apply a reverse bias voltage between the electrodes of the solar cell panel 90.

  The inspection apparatus 100 restores the time waveform of the electromagnetic wave pulse LT1 based on the detection result of the electric field intensity acquired in step S15 (FIG. 6: step S16). Specifically, the time waveform restoration unit 21 restores the time waveform of the electromagnetic wave pulse LT1 by plotting the value of the electric field intensity detected in step S15 along the time axis.

  FIG. 8 is a diagram showing a time waveform of the electromagnetic wave pulse LT1 restored by the time waveform restoration unit 21. As shown in FIG. In FIG. 8, the horizontal axis indicates time, and the vertical axis indicates electric field strength. In the lower stage, a plurality of detection pulse lights LP12 having different timings (that is, detection timings) reaching the detector 132 by the delay unit 131 are conceptually shown.

  When the inspection pulse light LP11 is irradiated to the position of interest, the electromagnetic wave pulse LT1 having the time waveform 41 as shown in FIG. 8 repeatedly arrives at the detector 132 at a predetermined period. Here, for example, when the delay unit 131 is adjusted such that the probe light reaches the detector 132 at the detection timing t <b> 1, the electric field strength of the value E <b> 1 is detected in the detector 132. When the delay unit 131 is adjusted so that the detection timing is t2 to t8, the electric field strengths of values E2 to E8 are detected, respectively. The time waveform 41 of the electromagnetic wave pulse LT1 is restored by plotting the electric field strength values E1 to E8 acquired in this way in a graph along the time axis.

  By restoring the time waveform 41, the characteristics of the photoexcited carrier generation region at the position of interest can be inspected. For example, the formation failure of the photoexcited carrier generation region can be detected from the presence or absence of detection of the electromagnetic wave pulse LT1 or the amplitude of the electric field strength of the restored electromagnetic wave pulse LT1.

  Returning to FIG. 6, when the time waveform 41 of the electromagnetic wave pulse LT1 is restored, the inspection apparatus 100 performs spectrum analysis (FIG. 6: step S17). Specifically, based on the time waveform acquired in step S16, the spectrum analysis unit 23 performs Fourier transform. Thereby, the spectrum distribution of the electromagnetic wave pulse LT1 is acquired. Note that step S17 can be omitted.

  FIG. 9 is a diagram showing the spectrum distribution 51 of the electromagnetic wave pulse LT1. In FIG. 9, the vertical axis indicates the spectral intensity, and the horizontal axis indicates the frequency. As shown in the spectrum distribution 51, the electromagnetic wave pulse LT1 generated from the solar cell panel 90 has a relatively strong spectrum intensity over 0.1 THz to 1 THz.

  By acquiring such a spectrum distribution 51, various physical property information regarding the position of interest in the solar cell panel 90 can be acquired. For example, by comparing the spectrum distribution 51 shown in FIG. 9 with another spectrum distribution serving as a reference, it is possible to relatively evaluate the physical property information of the position of interest of the solar cell panel 90. In the spectrum distribution 51, as indicated by the arrows, absorption occurs with respect to electromagnetic waves having a specific frequency. From this, it is presumed that the impurity that absorbs the specific frequency is formed at the position of interest, and the type and concentration of the impurity are also estimated from the frequency of the absorbed electromagnetic wave.

  Returning to FIG. 6, when the spectrum analysis is completed, an image showing the inspection result is displayed on the monitor 17 (FIG. 6: step S18). Specifically, the time waveform 41 (see FIG. 8) of the electromagnetic wave pulse LT1 acquired in step S16, the spectrum distribution 51 (see FIG. 9) acquired in step S17, and the like are displayed on the monitor 17 as analysis results. .

  Next, the inspection apparatus 100 determines whether to perform additional inspection by changing the irradiation condition of the continuous light CW (FIG. 6: step S19). If additional inspection is necessary (YES in step S19), the inspection apparatus 100 returns to step S12 to set the irradiation condition of the continuous light CW. If no additional inspection is necessary (NO in step S19), the inspection apparatus 100 ends the operation relating to the first inspection.

  FIG. 10 is a diagram illustrating time waveforms 61 and 62 of the electromagnetic wave pulse LT1. The time waveform 61 corresponds to the electromagnetic wave pulse LT1 detected when the continuous light CW is not irradiated, and the time waveform 62 is the electromagnetic wave pulse LT1 detected when the continuous light CW is irradiated. It corresponds to.

  As shown in FIG. 10, when the time waveforms 61 and 62 are compared, the amplitude of the electromagnetic wave pulse LT1 is relatively reduced by irradiating the continuous light CW. This is considered to be due to the following reasons. That is, when the continuous light CW is irradiated, the photoexcited carriers excited by the continuous light CW are filled in the conduction band. For this reason, it is considered that the current change of the photoexcited carrier generated by the inspection pulse light LP11 is relatively weakened, and the electric field strength of the generated electromagnetic wave pulse LT1 is also weakened. However, the tendency of the change in the amplitude of the electromagnetic wave pulse LT1 due to the irradiation of the continuous light CW is not necessarily common in all points of the solar cell panel 90. That is, the tendency may differ depending on the formation state of the depletion layer or the like.

<Second inspection>
Next, the second inspection will be described. FIG. 11 is a flowchart of the second inspection. In the second inspection, first, the solar cell panel 90 is fixed to the stage 11 (FIG. 11: Step S21). This step is the same as step S11 of the first inspection shown in FIG. Next, a reverse bias voltage is applied between the back surface electrode 92 and the light receiving surface electrode 96 of the solar cell panel 90 (FIG. 11: Step S22). Note that it is not always necessary to apply the reverse bias voltage, and the second inspection may be performed in a non-bias state.

  Next, the irradiation condition of the continuous light CW is set (FIG. 11: Step S23). Further, the irradiation of the continuous light CW and the irradiation of the inspection pulse light LP11 based on the irradiation conditions set in step S23 are started (FIG. 11: step S24). Steps S23 and S24 are substantially the same as steps S12, S13 and S14 of the first inspection shown in FIG. That is, the inspection pulse light LP11 is applied to a predetermined position of the light receiving surface 9FS of the solar cell panel 90. This predetermined position is a position on the solar cell panel 90, which is selected to determine the detection timing in step S25, which will be described later, and a position where an electromagnetic wave pulse LT1 having a magnitude at which the electric field strength can be detected is generated. It is said. Then, the continuous light CW is irradiated to the portion on the back surface 9BS side corresponding to the portion irradiated with the inspection pulse light LP11.

  In addition, the inspection apparatus 100 adjusts the delay unit 131 so that the electric field intensity of the electromagnetic wave pulse LT1 detected by the detector 132 is maximized (FIG. 11: Step S25). Specifically, the position of the folding mirror 10M in the delay unit 131 is adjusted, and the timing at which the detection pulsed light LP12 reaches the detector 132 is changed.

  For example, in the case of the electromagnetic wave pulse LT1 such as the time waveform 41 shown in FIG. 8, if the electromagnetic wave pulse LT1 is detected at the detection timing t3, the maximum intensity of the electromagnetic wave pulse LT1 can be detected by the detector 132. it can. Accordingly, in this case, the inspection apparatus 100 moves the folding mirror 10M to a position corresponding to the detection timing t3.

  Thus, it becomes easy to detect the electromagnetic wave pulse LT1 by detecting the maximum intensity of the electromagnetic wave pulse LT1. For this reason, the detection sensitivity of electromagnetic wave pulse LT1 can be improved and the test | inspection of the solar cell panel 90 can be performed appropriately. The maximum intensity of the electromagnetic wave pulse LT1 does not necessarily need to be detected by the detector 132. That is, the detection timing can be arbitrarily set in the detector 132 as long as at least measurement is possible.

  In setting the detection timing in step S25, irradiation with continuous light CW is not necessarily required. For this reason, it is also possible to omit the continuous light CW irradiation by the continuous light irradiation unit 14 while step S25 is being executed.

  When the adjustment of the delay unit 131 is completed, the inspection apparatus 100 drives the motor 15 to move the solar cell panel 90 within the two-dimensional plane (FIG. 11: step S26). At this time, the continuous light CW and the inspection pulse light LP11 are irradiated toward the solar cell panel 90. The electric field intensity of the electromagnetic wave pulse LT1 generated in response to the irradiation of the inspection pulse light LP11 is detected by the detector 132. Thereby, the electric field strength of the electromagnetic wave pulse LT1 generated from each point of the inspection target region on the solar cell panel 90 is acquired.

  The inspection apparatus 100 generates an image showing the electric field strength distribution based on the acquired electric field strength, and displays the image on the monitor 17 (FIG. 11: Step S27). FIG. 12 is a diagram illustrating an example of the electric field intensity distribution image 71. The electric field intensity distribution image 71 is an image in which corresponding portions of an image representing the solar cell panel 90 are separately painted with a plurality of colors according to the magnitude of the electric field intensity of the observed electromagnetic wave pulse LT1. In FIG. 12, the difference in color is expressed by the difference in hatching. In the electric field intensity distribution image 71, the electric field intensity is divided into three levels (intensity 0 to 4, intensity 4 to 8, intensity 8 to 10), and colors are colored according to the respective areas. However, the magnitude of the electric field strength may be divided into two stages or four or more stages to perform painting separately.

  As shown in FIG. 12, in the electric field intensity distribution image 71, a relatively strong electromagnetic wave pulse LT1 is detected in the peripheral portion of the light receiving surface electrode 96, and the detected electric field strength decreases as the distance from the light receiving surface electrode 96 increases. ing. This is presumably because the electric field strength of the generated electromagnetic wave pulse LT1 is relatively strong because a relatively strong internal electric field acts in a portion close to the electrode such as the light receiving surface electrode 96.

  By generating such an electric field intensity distribution image 71, the formation status of the photoexcited carrier generation region can be grasped at once over a wide range of the solar cell panel 90. In particular, in the present embodiment, since continuous light CW irradiation is also performed, it is possible to efficiently detect structural defects that may cause problems during use or to evaluate the performance of each part of the solar cell panel 90. Can do.

  Further, in the second inspection, only the instantaneous electric field strength is detected in the electromagnetic wave pulse LT1, but for example, as described in the first inspection, the delay unit 131 is controlled so that each point is detected. In addition, the time waveform of the electromagnetic wave pulse LT1 may be restored. Based on the spectral distribution obtained by Fourier transform of the acquired time waveform, for example, an image in which the spectral intensity of a specific frequency is expressed by color shading may be generated.

<2. Second Embodiment>
FIG. 13 is a schematic configuration diagram of the irradiation unit 12A and the detection unit 13A of the inspection apparatus 100A according to the second embodiment. In the following description, elements having the same functions as those of the components of the inspection apparatus 100 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Also in the inspection apparatus 100A, the pulse light LP1 emitted from the femtosecond laser 121 is split into the inspection pulse light LP11 and the detection pulse light LP12 by the beam splitter B1. However, in the present embodiment, the divided inspection pulse light LP11 passes through the transparent conductive film substrate (ITO) 19 and enters the light receiving surface 9FS of the solar cell panel 90 perpendicularly. Further, the continuous light irradiation unit 14 irradiates the continuous light CW from the side of the back surface 9BS of the solar cell panel 90 at a required incident angle (in the illustrated example, an angle parallel to the normal direction of the back surface 9BS). Among the electromagnetic wave pulses LT1 generated in response to the irradiation of the inspection pulse light LP11, the electromagnetic wave pulse LT1 radiated to the light receiving surface 9FS side reflects from the transparent conductive substrate 19 and is detected via a lens or the like. Incident 132.

  Also in the inspection apparatus 100A including the irradiation unit 12A and the detection unit 13A, the electromagnetic wave pulse LT1 generated in response to the irradiation of the inspection pulse light LP11 can be detected. Therefore, 100 A of inspection apparatuses can test | inspect the solar cell panel 90 in a non-contact state similarly to the inspection apparatus 100 which concerns on 1st Embodiment.

<3. Third Embodiment>
FIG. 14 is a schematic configuration diagram of the irradiation unit 12B and the detection unit 13B of the inspection apparatus 100B according to the third embodiment. Also in the inspection apparatus 100B, the pulsed light LP1 emitted from the femtosecond laser 121 is split into the inspection pulsed light LP11 and the detection pulsed light LP12 by the beam splitter B1. In the present embodiment, the inspection pulse light LP11 is perpendicularly incident on the back surface 9BS of the solar cell panel 90. The continuous light irradiation unit 14 irradiates the light receiving surface 9FS of the solar cell panel 90 with continuous light CW so as to be incident obliquely. Of the electromagnetic wave pulse LT1 generated in response to the irradiation of the inspection pulse light LP11, the electromagnetic wave pulse LT1 emitted (transmitted) to the back side of the solar cell panel 90 is collected by the parabolic mirrors M1 and M2. And enters the detector 132.

  Also in such an inspection apparatus 100B, it is possible to detect the electromagnetic wave pulse LT1 generated in response to the irradiation of the inspection pulse light LP11. Therefore, the inspection apparatus 100B can inspect the solar cell panel 90 in a non-contact state, similarly to the inspection apparatus 100 according to the first embodiment.

<4. Modification>
Although the embodiment has been described above, the present invention is not limited to the above, and various modifications are possible.

  For example, in the said embodiment, as FIG. 3 shows, the solar cell panel 90 in which the pn junction part was formed is made into the example. However, a solar cell panel in which a so-called pin junction is formed in which an intrinsic semiconductor layer is sandwiched between a p-type semiconductor layer and an n-type semiconductor layer can also be an inspection object of the inspection apparatus 100.

  In the inspection apparatus 100 according to the above-described embodiment, the solar cell panel 90 to be inspected is configured as a so-called single-sided solar cell panel in which the light receiving surface is set only on one surface. However, a double-sided light-receiving solar cell panel in which both surfaces (that is, the front surface and the back surface) are set as light-receiving surfaces can be inspected in the same manner as the solar cell panel 90. That is, pulse light (inspection pulse light LP11) may be irradiated on one surface of the light receiving surfaces on both surfaces of the double-sided light receiving solar cell panel, and continuous light CW may be irradiated from the other back surface.

  In the above embodiment, the irradiation position of the inspection pulse light LP11 and the continuous light CW is changed by moving the stage 11. However, it is also conceivable to optically change the irradiation positions of the inspection pulse light LP11 and the continuous light CW by controlling an optical element included in the irradiation unit 12 or the continuous light irradiation unit 14, for example.

  Moreover, the back surface electrode 92 of the solar cell 90 that is the inspection object may be formed of a transparent electrode. In this case, the continuous light CW can be easily transmitted through the back electrode 92, which is advantageous in that the restriction on the shape of a grid or the like can be reduced.

  In addition, in the inspection apparatuses 100, 100A, and 100B according to the above-described embodiments, a solar cell panel in which the light receiving surface electrode 96 and the back surface electrode 92 are not formed can be an inspection target. In this case, the photoexcited carriers are moved toward the respective electrodes by bringing the electrodes having shapes that do not interfere with the irradiation of the inspection pulse light LP11 and the continuous light CW to the light receiving surface side and the back surface side of the solar cell, respectively. Can do. Of course, when either one of the light receiving surface electrode 96 and the back surface electrode 92 is not formed, the electrode may be brought into contact with the surface side where the light receiving surface electrode 96 and the back surface electrode 92 are not formed.

  In addition, the configurations described in the above embodiments and modifications can be appropriately combined or omitted as long as they do not contradict each other.

  Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

100, 100A, 100B inspection apparatus 11 stage 12, 12A, 12B irradiation unit 121 femtosecond laser 13, 13A, 13B detection unit 131 delay unit 132 detector 14 continuous light irradiation unit 141 irradiation condition change unit 16 control unit 21 time waveform recovery Unit 23 Spectrum analysis unit 25 Image generation unit 41, 61, 62 Time waveform 51 Spectrum distribution 71 Electric field intensity distribution image 81 Continuous light irradiation part 83 Pulse light irradiation part 90 Solar cell panel 9FS Light receiving surface 9BS Back surface 92 Back surface electrode 93 P-type silicon Layer 94 n-type silicon layer 96 light-receiving surface electrode 97 pn junction 99 reverse bias voltage application circuit CW continuous light LP11 inspection pulse light LP12 detection pulse light LT1 electromagnetic wave pulse

Claims (7)

An inspection apparatus for inspecting a photo device,
An irradiation unit that irradiates one light receiving surface of both sides of the photo device with pulsed light emitted from a femtosecond laser;
A detection unit for detecting electromagnetic waves generated from the photo device in response to the irradiation of the pulsed light;
A continuous light irradiating unit that irradiates continuous light to a portion of the back surface opposite to the light receiving surface, corresponding to the portion of the light receiving surface irradiated with the pulsed light,
An inspection device. The inspection apparatus according to claim 1,
An inspection apparatus further comprising: an irradiation condition changing unit that changes at least one of the irradiation diameter, intensity, and wavelength of the continuous light. The inspection apparatus according to claim 1 or 2,
The inspection apparatus, wherein the continuous light includes light having a plurality of different wavelengths. The inspection apparatus according to claim 3, wherein
The inspection apparatus, wherein the photo device is a solar cell and the continuous light includes pseudo-sunlight. The inspection apparatus according to claim 1 or 2,
The said continuous light is a test | inspection apparatus which is a laser beam of a single wavelength. In the inspection apparatus according to any one of claims 1 to 5,
A reverse bias voltage application unit for applying a voltage for setting the photo device in a reverse bias state;
An inspection device further comprising: An inspection method for inspecting a photo device,
(a) irradiating the light receiving surface of the photo device with pulsed light emitted from a femtosecond laser;
(b) detecting an electromagnetic wave generated from the photo device in response to the irradiation of the pulsed light;
(c) in the step (a), a step of irradiating continuous light to a portion of the back surface opposite to the light receiving surface corresponding to the portion of the light receiving surface irradiated with the pulsed light; ,
Having an inspection method.

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