Light receiving element inspection device and light receiving element inspection method

Abstract

The light-receiving element inspection device disclosed herein is a light-receiving element inspection device (500) for inspecting a back-illuminated light-receiving element (110), and includes: a measurement stage (102) in which an area including at least an element mounting portion (111) for mounting the back-illuminated light-receiving element (110) is made of a material transparent to laser light; anti-reflection films (115a, 115b) formed on the surface of the element mounting portion (111) and on the surface of a portion facing the element mounting portion (111) on the back side of the measurement stage (102); a light source unit (300) that emits laser light and can select either CW light or pulsed light; and an optical fiber unit (125) having one end connected to the light source unit (300), guiding the laser light, and emitting the laser light from the other end toward the portion facing the element mounting portion (111).

Description

[Technical field]

[0001] The present disclosure relates to a light receiving element inspection device and a light receiving element inspection method. [Background technology]

[0002] As an example of an apparatus and method for inspecting a light-receiving element, the light-receiving element inspection apparatus described in Patent Document 1 measures the optical sensitivity of a photodiode by setting a semiconductor wafer on which multiple photodiodes are mounted on a wafer tester, irradiating a single photodiode with laser light from a laser head, and calculating an optical sensitivity value based on the output voltage at this time.

[0003] Furthermore, in a light receiving element inspection device different from that of Patent Document 1, inspection is performed on a back illuminated light receiving element that is flip-chip mounted on a submount. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-324588 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the light-receiving element inspection device described in Patent Document 1, measurements are performed on a semiconductor wafer basis, and therefore the influence of peripheral circuits of the light-receiving element is not taken into consideration during measurement.

[0006] In a photodetector inspection method in which a back-illuminated photodetector is inspected in a state where it is flip-chip mounted on a submount, it is necessary to first flip-chip mount the back-illuminated photodetector in order to measure the device characteristics of the back-illuminated photodetector. In other words, there was a problem in that the device characteristics could not be measured in the state of the back-illuminated photodetector alone before flip-chip mounting.

[0007] The present disclosure has been made to solve the problems described above, and aims to provide a photodetector inspection apparatus and a photodetector inspection method that are capable of accurately inspecting the element characteristics of a single back-illuminated photodetector. [Means for solving the problem]

[0008] The light receiving element inspection device according to the present disclosure comprises: A light receiving element inspection apparatus for inspecting a back-illuminated light receiving element that receives laser light incident from a back side, comprising: a measurement stage having an element mounting portion on which the light receiving surface of the back-illuminated light receiving element is placed in contact with the element mounting portion, the element mounting portion being made of a material transparent to the laser light; an anti-reflection film formed on a surface of the element mounting portion and on a surface of a portion of the back side of the measurement stage facing the element mounting portion, the anti-reflection film preventing reflection of the laser light; a light source unit that emits the laser light to a light receiving surface provided on the back side of the back illuminated type light receiving element and is capable of selecting either CW light or pulsed light of the laser light; an optical fiber section having one end connected to the light source section, guiding the laser light, and emitting the laser light from the other end toward a portion facing the element mounting portion; 、 the other end of the optical fiber portion is an obliquely polished surface that is inclined at a preset angle with respect to the optical axis; The portion of the back surface of the measurement stage facing the element placement portion has a lens shape. .

[0009] The light receiving element inspection method according to the present disclosure includes: 1. A method for inspecting a back-illuminated light-receiving element that receives laser light incident from a back surface side, comprising: a step of placing the back-illuminated light-receiving element in contact with an element mounting portion having an anti-reflection film formed on a front side and a back side of the element mounting portion, the anti-reflection film preventing reflection of the laser light, on a measurement stage made of a material transparent to the laser light; a step of emitting the laser light emitted from a light source unit toward a portion facing the element mounting portion on a rear surface side of the measurement stage through an optical fiber unit; and a step of contacting a probe with a front surface side of the back-illuminated light-receiving element to measure element characteristics of the back-illuminated light-receiving element. 、 The optical fiber portion, which is made of a polarization-maintaining optical fiber, is rotated about the optical axis direction to emit laser light whose polarization direction has been rotated, and the polarization dependence of the element characteristics of the back-illuminated light-receiving element is measured. . Effect of the Invention

[0010] The photodetector inspection apparatus and photodetector inspection method disclosed herein enable inspection of a back-illuminated photodetector alone and eliminates the need to assemble the back-illuminated photodetector before inspecting the element characteristics. This has the effect of enabling inspection under the same conditions as the final product before incorporating the back-illuminated photodetector in the final product. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic view of a light-receiving element inspection apparatus according to a first embodiment. [Diagram 2] 11 is a schematic view of a light-receiving element inspection apparatus according to a second embodiment. FIG. [Diagram 3] 11 is a schematic view of a light-receiving element inspection apparatus according to a third embodiment. FIG. [Figure 4] FIG. 13 is a general view of a light-receiving element inspection apparatus according to a fourth embodiment. [Diagram 5] FIG. 13 is a schematic view of a light-receiving element inspection device according to a fifth embodiment. [Figure 6] 13 is a general view of a light-receiving element inspection device according to a sixth embodiment. FIG. [Figure 7] 13 is a top view of a measurement stage of a light-receiving element inspection apparatus according to embodiment 6. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Embodiment 1 <Configuration of the Light-Receiving Element Inspection Apparatus According to the First Embodiment> 1 is a schematic diagram of a light-receiving element inspection apparatus 500 according to embodiment 1. The light-receiving element inspection apparatus 500 includes an inspection unit 100, a power supply unit 200, and a light source unit 300.

[0013] The light-receiving element inspection apparatus 500 is particularly suitable for measuring the back-illuminated light-receiving element 110, but can also measure light-receiving elements other than the back-illuminated light-receiving element 110.

[0014] <Testing Department Configuration> The inspection section 100 comprises a measurement stage 102, a measurement stage leg 102a consisting of multiple legs that support the measurement stage 102, a probe 105 that contacts the back-illuminated light receiving element 110 to pass a measurement current, an optical fiber section 125 that is installed on the back side of the measurement stage 102, guides laser light emitted from the light source section 300, and has a lens section 126 whose tip is machined into a lens shape, and an XYZ stage 130 that moves the optical fiber section 125 in three dimensions.

[0015] On the upper surface (hereinafter referred to as the front surface, and the surface opposite to the upper surface referred to as the back surface) of the measurement stage 102, at least an area including a portion (hereinafter referred to as element placement portion 111) on which the back-illuminated light-receiving element 110 is placed when measuring the back-illuminated light-receiving element 110 is made of a material (hereinafter referred to as a transparent material) that is transparent to the laser light emitted from the light source section 300. The entire measurement stage 102 may be made of a transparent material.

[0016] An antireflection film 115a is formed on the surface of the element placement portion 111 of the measurement stage 102. An antireflection film 115b is formed on the surface of a portion of the back side of the measurement stage 102 facing the element placement portion 111. The antireflection film 115a may be embedded in a transparent member constituting the measurement stage 102 so that the surface of the measurement stage 102 coincides with the surface of the antireflection film 115a. The antireflection film 115b may be embedded in a transparent member constituting the measurement stage 102 so that the back side of the measurement stage 102 coincides with the surface of the antireflection film 115b. The antireflection films 115a and 115b have the function of preventing reflection of laser light.

[0017] The lens section 126 provided at the tip of the optical fiber section 125 is provided to focus the laser light guided within the optical fiber section 125 onto the light receiving surface of the back-illuminated light receiving element 110 placed on the measurement stage 102. When focusing the laser light, the optical fiber section 125 is moved in three dimensional directions using the XYZ stage 130, thereby adjusting the focus of the lens section 126 so that it coincides with the light receiving surface (not shown) provided on the back side of the back-illuminated light receiving element 110.

[0018] In the light-receiving element inspection apparatus 500 according to the first embodiment, the back-illuminated light-receiving element 110 to be measured is placed on an element mounting portion 111 provided so as to be substantially flush with the measurement stage 102. Since the laser light emitted from the lens portion 126 is incident on the back surface of the back-illuminated light-receiving element 110 from a substantially perpendicular direction, a part of the laser light is reflected by the back surface of the back-illuminated light-receiving element 110, which may reduce the input of the laser light to the back-illuminated light-receiving element 110 or cause multiple reflections of the laser light. Therefore, an anti-reflection film 115a is formed on the element mounting portion 111 and an anti-reflection film 115b is formed on the surface of the portion facing the element mounting portion 111 on the back side of the measurement stage 102, thereby preventing reflection of the laser light by the back surface of the back-illuminated light-receiving element 110.

[0019] <Power supply configuration> The power supply unit 200 includes a power supply 201, a first electric switch 202 connected to an output terminal Vpd of the power supply 201, a variable resistor 203 arranged between point B1 and the electric wiring on the output side of the first electric switch 202, a variable capacitance bypass capacitor 204 connected to the ground terminal GND of the power supply 201, and a second electric switch 205 arranged between the output terminal Vpd and the ground terminal GND. The output terminal Vpd and the ground terminal GND are each connected to the probe 105.

[0020] The first electrical switch 202 can be connected to either point A1 or point B1 to select whether or not there is a variable resistor 203 connected in series to the output terminal Vpd. The second electrical switch 205 can be connected to either point A2 or point B2 to select whether or not there is a variable capacitance bypass capacitor 204 connected in series to the ground terminal GND.

[0021] <Light source configuration> The light source unit 300 includes a light source 304 configured by a DFB-LD and emitting laser light, a Peltier element 303 and a temperature controller 301 that control the temperature of the light source 304 to a constant value, a function generator 302 that controls the laser light emitted from the light source 304 to generate CW light or pulsed light, an optical switch 305 connected to the light source 304 by optical wiring, an optical attenuator 306 connected to the optical switch 305, and an optical switch 307 that selects the laser light from the optical switch 305 and the laser light from the optical attenuator 306.

[0022] The optical switch 305 selects whether the laser light passes through the optical attenuator 306 by selecting either the path C or the path D. The optical attenuator 306 monitors the power of the light output from the optical fiber unit 125 before measurement. Moreover, the optical attenuator 306 can set the input laser light to a desired attenuation amount.

[0023] The laser light emitted from the light source section 300 is input to the optical fiber section 125 of the inspection section 100 via an optical wiring.

[0024] <Photo-receiving element inspection method according to the first embodiment> The light receiving element inspection method according to the first embodiment will be described below. A back-illuminated light-receiving element 110 to be measured is placed on an element placement portion 111 of the measurement stage 102. When placing the element, the back side of the back-illuminated light-receiving element 110, i.e., the side on which the light-receiving surface is provided, is placed on the element placement portion 111.

[0025] A Peltier element 303 is driven by a temperature controller 301 to control a DFB-LD, which is a light source 304, to a desired constant temperature.

[0026] If path C is selected, the laser light emitted from the DFB-LD is emitted to the inspection unit 100 via optical switch 305 and optical switch 307, and if path D is selected, the laser light is emitted to the inspection unit 100 via optical switch 305, optical attenuator 306, and optical switch 307.

[0027] The laser light guided to the optical fiber section 125 is focused by the lens section 126 provided at the tip of the optical fiber section 125, and is focused on a light receiving surface provided on the back side of the back-illuminated light receiving element 110 placed on the element mounting portion 111 of the measurement stage 102.

[0028] When focusing the laser light, the optical fiber section 125 is moved in three dimensions using the XYZ stage 130, and adjustment is performed in advance before measurement so that the focal point of the lens section 126 is on the light receiving surface of the back-illuminated light receiving element 110.

[0029] A probe 105 is brought into contact with the front side of a back-illuminated light receiving element 110 on an element placement portion 111 of a measurement stage 102, and various element characteristics of the back-illuminated light receiving element 110 receiving laser light are measured.

[0030] In the power supply unit 200, the first electrical switch 202 selects point A1 and the second electrical switch 205 selects point A2, and in the light source unit 300, the optical switch 305 selects path C, thereby obtaining the basic element characteristics of the back-illuminated photodetector 110 using CW laser light and electrical wiring in the absence of the variable resistor 203 and the variable capacitance bypass capacitor 204.

[0031] In the power supply unit 200, the first electrical switch 202 selects point B1 and the second electrical switch 205 selects point B2, and in the light source unit 300, the optical switch 305 selects path D, whereby basic element characteristics of the back-illuminated light receiving element 110 are obtained using pulsed laser light and electrical wiring in the case where the variable resistor 203 and the variable capacitance bypass capacitor 204 are present. By appropriately adjusting the resistance value of the variable resistor 203 and the capacitance of the variable capacitance bypass capacitor 204, it is possible to obtain element characteristics that meet the customer's usage conditions.

[0032] An inspection may be performed taking into consideration the customer's usage conditions, such as a transient response at the time of optical input, by changing the defocus amount of the lens unit 126 in accordance with the customer's usage conditions and making the requested CW light or pulsed light incident on the back-illuminated photodetector 110. In addition, when performing an optical over-input resistance test of the back-illuminated photodetector 110, the optical switch 305 may select path C, and the back-illuminated photodetector 110 may be inspected using optical wiring that does not pass through the optical attenuator 306.

[0033] <Advantages of the First Embodiment> As described above, the light receiving element inspection device and the light receiving element inspection method according to the first embodiment have the effect that assembly before characteristic inspection of the back illuminated light receiving element is not necessary, and various element characteristics can be inspected for the back illuminated light receiving element alone. Therefore, it is possible to select the back illuminated light receiving element before incorporating it into the final product, and since the back illuminated light receiving element is measured alone, there is no influence of the parasitic capacitance of the submount, and it is possible to evaluate the element characteristics of the element alone. Furthermore, it has the effect that inspection under the same conditions as the final product is possible before incorporating it into the final product. In addition, the light receiving element inspection device and the light receiving element inspection method according to the first embodiment have the effect that the occurrence of return light caused by multiple reflections of laser light can be more efficiently prevented, since anti-reflection films are formed on the surface of the element mounting portion and on the surface of the portion facing the element mounting portion on the back side of the measurement stage.

[0034] Embodiment 2 2 is a schematic diagram of a light-receiving element inspection apparatus 500a according to embodiment 2. The light-receiving element inspection apparatus 500a includes an inspection section 100a, a power supply section 200, and a light source section 300.

[0035] The light-receiving element inspection apparatus 500a is particularly suitable for measuring the back-illuminated light-receiving element 110, but can also measure light-receiving elements other than the back-illuminated light-receiving element 110.

[0036] The power supply unit 200 and the light source unit 300 of the light-receiving element inspection apparatus 500a according to the second embodiment are the same as those of the light-receiving element inspection apparatus 500a according to the first embodiment, and only the inspection unit is different. Therefore, hereinafter, only the inspection unit 100a of the light-receiving element inspection apparatus 500a according to the second embodiment will be described.

[0037] <Testing Department Configuration> The inspection unit 100a includes a measurement stage 102, a measurement stage leg 102a consisting of multiple legs that support the measurement stage 102, a probe 105 that contacts the back-illuminated light receiving element 110 to pass a measurement current, an optical fiber unit 125 that is installed on the back side of the measurement stage 102, guides the laser light emitted from the light source unit 300, and has a lens unit 126 whose tip is machined into a lens shape, and an XYZ stage 130 that moves the optical fiber unit 125 in three dimensions.

[0038] In the measurement stage 102, at least a region including an element mounting portion 111a on which the back-illuminated light receiving element 110 is mounted when measuring the back-illuminated light receiving element 110 is made of a transparent material with respect to the laser light emitted from the light source section 300. The entire measurement stage 102 may be made of a transparent material.

[0039] The element placement portion 111a of the measurement stage 102 is provided with an inclined surface inclined at a preset angle with respect to the surface of the measurement stage 102. In other words, it can be said that the element placement portion 111a provided on the surface side of the measurement stage 102 is an inclined surface inclined at a preset angle with respect to the surface of the measurement stage 102. An antireflection film 115a is formed on this inclined surface. As shown in FIG. 2, one end of the antireflection film 115a is located at the same height as the surface of the measurement stage 102, and the other end of the antireflection film 115a is located inward from the surface of the measurement stage 102.

[0040] An antireflection film 115b is formed on the back surface side facing the element placement site 111a consisting of the inclined surface of the measurement stage 102. The antireflection film 115b may be embedded in a transparent member constituting the measurement stage 102 so that the back surface of the measurement stage 102 coincides with the surface of the antireflection film 115b.

[0041] In the photodetector inspection apparatus 500a according to the second embodiment, when the laser light emitted from the lens portion 126 provided at the tip of the optical fiber portion 125 is focused on the light receiving surface of the back-illuminated photodetector 110 placed on the measurement stage 102, it is possible to prevent multiple reflections of the laser light.

[0042] In the light-receiving element inspection apparatus 500 according to the first embodiment described above, multiple reflections of laser light by the back surface of the back-illuminated light-receiving element 110 are prevented by the antireflection film 115a formed on the element mounting portion 111 and the antireflection film 115b formed on a portion facing the element mounting portion 111 on the back side of the measurement stage 102, but there is a risk that the return light due to reflection cannot be completely prevented. Therefore, in the light-receiving element inspection apparatus 500a according to the second embodiment, by providing the element mounting portion 111a consisting of an inclined surface, it becomes possible to more efficiently prevent the occurrence of return light due to multiple reflections.

[0043] <Advantages of the second embodiment> As described above, according to the light-receiving element inspection device of embodiment 2, by providing an element mounting portion consisting of an inclined surface on the front surface side of the measurement stage, it is possible to more efficiently prevent the occurrence of return light caused by multiple reflections of laser light.

[0044] Embodiment 3 3 is a schematic view of a light-receiving element inspection apparatus 500b according to embodiment 3. The light-receiving element inspection apparatus 500b includes an inspection section 100b, a power supply section 200, and a light source section 300.

[0045] The light-receiving element inspection apparatus 500b is particularly suited for measuring the back-illuminated light-receiving element 110, but can also measure light-receiving elements other than the back-illuminated light-receiving element 110.

[0046] The power supply unit 200 and the light source unit 300 of the light-receiving element inspection apparatus 500b according to the third embodiment are the same as those of the light-receiving element inspection apparatus 500b according to the first embodiment, and only the inspection unit is different. Therefore, hereinafter, only the inspection unit 100b of the light-receiving element inspection apparatus 500b according to the third embodiment will be described.

[0047] <Testing Department Configuration> The inspection unit 100b includes a measurement stage 102, a measurement stage leg 102a consisting of multiple legs that support the measurement stage 102, a probe 105 that contacts the back-illuminated light receiving element 110 to pass a measurement current, an optical fiber unit 125a that is installed on the back side of the measurement stage 102, guides the laser light emitted from the light source unit 300, and has an obliquely polished portion 126a whose tip is polished obliquely with respect to the optical axis direction, and an XYZ stage 130 that moves the optical fiber unit 125a in three dimensions.

[0048] In the measurement stage 102, at least a region including an element mounting portion 111 on which the back-illuminated light-receiving element 110 is mounted when measuring the back-illuminated light-receiving element 110 is made of a transparent material with respect to the laser light emitted from the light source section 300. The entire measurement stage 102 may be made of a transparent material.

[0049] An anti-reflection film 115a is formed on the surface of the element mounting portion 111 of the measurement stage 102. A portion of the back side of the measurement stage 102 facing the element mounting portion 111 presents a lens spherical portion 102b. An anti-reflection film 115b is formed on the surface of the lens spherical portion 102b.

[0050] In the photodetector inspection apparatus 500b according to the third embodiment, the laser light emitted from the obliquely polished portion 126a provided at the tip of the optical fiber portion 125 is focused onto the light receiving surface of the back-illuminated photodetector 110 using the lens spherical portion 102b provided on the back side of the measurement stage 102.

[0051] In the light-receiving element inspection apparatus 500b according to the third embodiment, multiple reflections of laser light by the back surface of the back-illuminated light-receiving element 110 are prevented by the anti-reflection film 115a formed on the surface of the element mounting portion 111 and the anti-reflection film 115b formed on the surface of the lens spherical portion 102b provided at a portion facing the element mounting portion 111 on the back side of the measurement stage 102, so that it is possible to efficiently prevent the generation of return light due to multiple reflections of laser light.

[0052] <Advantages of the Third Embodiment> As described above, according to the light-receiving element inspection device of embodiment 3, a lens spherical portion is provided on the back side of the measurement stage, making it possible to efficiently focus laser light. In addition, the anti-reflection film formed on the front side of the measurement stage and the anti-reflection film formed on the surface of the lens spherical portion make it possible to efficiently prevent the generation of return light caused by multiple reflections of laser light.

[0053] Embodiment 4 4 is a schematic view of a light-receiving element inspection apparatus 500c according to embodiment 4. The light-receiving element inspection apparatus 500c includes an inspection section 100c, a power supply section 200, and a light source section 300.

[0054] The light-receiving element inspection apparatus 500c is particularly suitable for measuring the back-illuminated light-receiving element 110, but can also measure light-receiving elements other than the back-illuminated light-receiving element 110.

[0055] The power supply unit 200 and the light source unit 300 of the light-receiving element inspection apparatus 500c according to the fourth embodiment are the same as those of the light-receiving element inspection apparatus 500c according to the first embodiment, and only the inspection unit is different. Therefore, hereinafter, only the inspection unit 100c of the light-receiving element inspection apparatus 500c according to the fourth embodiment will be described.

[0056] <Testing Department Configuration> The inspection unit 100c includes a measurement stage 102, a measurement stage leg 102a consisting of multiple legs that support the measurement stage 102, a probe 105 that contacts the back-illuminated light receiving element 110 to pass a measurement current, an optical fiber unit 125b that is installed on the back side of the measurement stage 102, guides the laser light emitted from the light source unit 300, and has a lens unit 126 whose tip is machined into a lens shape, and an XYZ stage 130a that moves the optical fiber unit 125b in three dimensional directions and is equipped with a rotation mechanism that enables the optical fiber unit 125b to rotate around the optical axis direction.

[0057] The optical fiber constituting the optical fiber portion 125b is a polarization-maintaining optical fiber. By rotating the optical fiber portion 125b around the optical axis direction by the XYZ stage 130a, the laser light with the rotated polarization direction is made incident on the light receiving surface of the back-illuminated light receiving element 110.

[0058] In the photodetector inspection apparatus 500c according to the fourth embodiment, in addition to the element characteristics of the back-illuminated photodetector 110 that can be measured by the photodetector inspection apparatus 500 according to the first embodiment, it is possible to further measure the polarization dependency.

[0059] <Advantages of the Fourth Embodiment> As described above, the photodetector inspection device according to the fourth embodiment is provided with a rotation mechanism that rotates the polarization-maintaining optical fiber around the optical axis direction, which has the effect of making it possible to further measure the polarization dependence of the back-illuminated photodetector.

[0060] Embodiment 5. 5 is a schematic view of a light-receiving element inspection apparatus 500d according to the fifth embodiment. The light-receiving element inspection apparatus 500d includes an inspection section 100d, a power supply section 200, and a light source section 300.

[0061] The light-receiving element inspection apparatus 500d is particularly suitable for measuring the back-illuminated light-receiving element 110, but can also measure light-receiving elements other than the back-illuminated light-receiving element 110.

[0062] The power supply unit 200 and the light source unit 300 of the light-receiving element inspection apparatus 500d according to the fifth embodiment are the same as those of the light-receiving element inspection apparatus 500d according to the first embodiment, and only the inspection unit is different. Therefore, hereinafter, only the inspection unit 100d of the light-receiving element inspection apparatus 500d according to the fifth embodiment will be described.

[0063] <Testing Department Configuration> The inspection unit 100d includes a measurement stage 102, a measurement stage leg 102a consisting of multiple legs that support the measurement stage 102, a probe 105 that contacts the back-illuminated light receiving element 110 to pass a measurement current, an optical fiber unit 125 that is installed on the back side of the measurement stage 102 and guides the laser light emitted from the light source unit 300 and has a lens unit 126 whose tip is machined into a lens shape, and an XYZ stage 130b that moves the optical fiber unit 125 in three dimensional directions and has a rotation mechanism that supports a wave plate 140 that is arranged between the optical fiber unit 125 and the measurement stage 102 and enables rotational movement around the optical axis direction.

[0064] An example of the wave plate 140 is a λ / 2 plate. Here, λ is the wavelength of the laser light emitted from the light source unit 300.

[0065] The wavelength plate 140 is rotated around the optical axis direction by a rotation mechanism provided on the XYZ stage 130 b , so that the laser light with the rotated polarization direction is incident on the light receiving surface of the back-illuminated light receiving element 110 .

[0066] In the photodetector inspection apparatus 500d according to the fifth embodiment, in addition to the element characteristics of the back-illuminated photodetector 110 that can be measured by the photodetector inspection apparatus 500 according to the first embodiment, it is possible to further measure the polarization dependency.

[0067] <Advantages of the Fifth Embodiment> As described above, according to the photodetector inspection device of the fifth embodiment, the wave plate that can be rotated around the optical axis direction is disposed between the optical fiber section and the measurement stage, thereby making it possible to further measure the polarization dependence of the back-illuminated photodetector.

[0068] Embodiment 6 Fig. 6 is a schematic view of a light-receiving element inspection apparatus 500e according to embodiment 6. Fig. 7 is a top view of a measurement stage 102c of the light-receiving element inspection apparatus 500e according to embodiment 6. The light-receiving element inspection apparatus 500e includes an inspection unit 100e, a power supply unit 200, and a light source unit 300.

[0069] The light-receiving element inspection apparatus 500e is particularly suitable for measuring the back-illuminated light-receiving element 110, but can also measure light-receiving elements other than the back-illuminated light-receiving element 110.

[0070] The power supply unit 200 and the light source unit 300 of the light-receiving element inspection apparatus 500e according to the sixth embodiment are the same as those of the first embodiment, and only the inspection unit is different. Therefore, hereinafter, only the inspection unit 100e of the light-receiving element inspection apparatus 500e according to the sixth embodiment will be described.

[0071] <Testing Department Configuration> The inspection unit 100e includes a measurement stage 102c, a measurement stage leg 102a consisting of multiple legs that support the measurement stage 102c, a plurality of thermistors 160 embedded inside the measurement stage 102c, a plurality of Peltier elements 150 provided at a portion of the measurement stage leg 102a that contacts the measurement stage 102c, a plurality of temperature controllers 170 connected to the thermistors 160 and the Peltier elements 150, a probe 105 that contacts the back-illuminated light receiving element 110 and passes a measurement current, an optical fiber unit 125 that is installed on the back side of the measurement stage 102, guides laser light emitted from the light source unit 300, and has a lens unit 126 whose tip is machined into a lens shape, and an XYZ stage 130 that moves the optical fiber unit 125 in three dimensional directions.

[0072] FIG. 7 is a top view of a measurement stage 102c showing an example of the arrangement of four thermistors 160, four Peltier elements 150, and four temperature controllers 170 in a light-receiving element inspection apparatus 500e according to the sixth embodiment.

[0073] In the light-receiving element inspection apparatus 500e according to the sixth embodiment, the temperature of the back-illuminated light-receiving element 110 is controlled via the measurement stage 102c by using the above-mentioned Peltier element 150. The temperature controller 170 controls the Peltier element 150 while referring to the temperature value measured by the thermistor 160 embedded inside the measurement stage 102c, thereby controlling the temperature of the back-illuminated light-receiving element 110 to a desired temperature.

[0074] In the light-receiving element inspection apparatus 500e according to the sixth embodiment, the temperature control of the back-illuminated light-receiving element 110 by the Peltier element 150 can be used to further measure the temperature dependence of each element characteristic of the back-illuminated light-receiving element 110.

[0075] <Advantages of the Sixth Embodiment> As described above, according to the light-receiving element inspection apparatus and the light-receiving element inspection method of the sixth embodiment, the temperature of the back-illuminated light-receiving element is controlled by a Peltier element, which has the effect of making it possible to further measure the temperature dependence of the element characteristics of the back-illuminated light-receiving element.

[0076] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.

[0077] Therefore, countless modifications not illustrated are assumed within the scope of the technology of the present disclosure, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment. [Explanation of symbols]

[0078] 100, 100a, 100b, 100c, 100d, 100e inspection unit, 102, 102c measurement stage, 102a measurement stage leg, 102b lens spherical surface portion, 105 probe, 110 back-illuminated light receiving element, 111, 111a element mounting portion, 115a anti-reflection film, 115b anti-reflection film, 125, 125a, 125b optical fiber portion, 126 lens portion, 130, 130a, 130b XYZ stage, 150, 303 Peltier element, 160 thermistor, 200 power supply unit, 201 power supply, 202 first electric switch, 203 variable resistor, 204 capacitance variable bypass capacitor, 205 second electric switch, 300 light source unit, 170, 301 temperature controller, 302 Function generator, 304 light source, 305, 307 optical switch, 306 optical attenuator, 500, 500a, 500b, 500c, 500d, 500e light receiving element inspection device

Claims

1. A light-receiving element inspection apparatus for inspecting a back-surface incident type light-receiving element that receives laser light incident from the back surface side, a measurement stage composed of a member transparent to the laser light, in which a region including an element placement portion for placing the light-receiving surface side of the back-surface incident type light-receiving element in contact is provided; an antireflection film formed on the surface of the element placement portion and the surface of the portion facing the element placement portion on the back surface side of the measurement stage, respectively, for preventing reflection of the laser light; a light source unit that emits the laser light to a light-receiving surface provided on the back surface side of the back-surface incident type light-receiving element and can select either CW light or pulsed light of the laser light; an optical fiber unit having one end connected to the light source unit, guiding the laser light, and emitting the laser light from the other end toward a portion facing the element placement portion; A light-receiving element inspection apparatus comprising:

2. a probe for measuring the element characteristics of the back-surface incident type light-receiving element; a power supply unit for supplying current to the probe; The light-receiving element inspection apparatus according to claim 1, further comprising:

3. The light-receiving element inspection apparatus according to claim 1 or 2, wherein the other end of the optical fiber unit has a lens shape.

4. The light-receiving element inspection apparatus according to claim 1 or 2, wherein the element placement portion on the front surface side of the measurement stage is an inclined surface inclined at a preset angle with respect to the front surface of the measurement stage.

5. The other end of the optical fiber unit is an obliquely polished surface inclined at a preset angle with respect to the optical axis direction, The light-receiving element inspection apparatus according to claim 1 or 2, wherein the portion facing the element placement portion on the back surface side of the measurement stage has a lens shape.

6. The light-receiving element inspection apparatus according to claim 1 or 2, further comprising a rotation mechanism for rotating the optical fiber unit made of a polarization-maintaining type optical fiber about the optical axis direction.

7. The light-receiving element inspection apparatus according to claim 1 or 2, wherein a wavelength plate is provided between the portion facing the element placement portion on the back surface side of the measurement stage and the other end of the optical fiber unit.

8. The light-receiving element inspection apparatus according to claim 1 or 2, wherein a plurality of temperature control elements are provided in contact with the measurement stage.

9. The light-receiving element inspection apparatus according to claim 8, wherein the temperature control element is in contact with each of the portions at the vertices of a quadrilateral centered on the element placement portion of the measurement stage in a plan view.

10. The light-receiving element inspection apparatus according to claim 8, wherein the temperature control element is a Peltier element.

11. A light-receiving element inspection method for inspecting a back-incident type light-receiving element that receives laser light incident from the back side, comprising: a step of placing the light-receiving surface side of the back-incident type light-receiving element in contact with an element placement portion formed with an antireflection film for preventing reflection of the laser light on both the front surface side and the back surface side, on a measurement stage composed of a member transparent to the laser light; a step of emitting the laser light emitted from a light source unit through an optical fiber unit toward a portion facing the element placement portion on the back surface side of the measurement stage; a step of bringing a probe into contact with the front surface side of the back-incident type light-receiving element and measuring the element characteristics of the back-incident type light-receiving element; A light-receiving element inspection method comprising the above steps.

12. The light-receiving element inspection method according to claim 11, wherein the polarization dependence of the element characteristics of the back-incident type light-receiving element is measured by rotating the optical fiber unit made of a polarization-maintaining type optical fiber about the optical axis direction to emit laser light with a rotated polarization direction.

13. The light-receiving element inspection method according to claim 11, wherein the polarization dependence of the element characteristics of the back-incident type light-receiving element is measured by rotating a wavelength plate provided between a portion facing the element placement portion on the back surface side of the measurement stage and the other end of the optical fiber unit.

14. The light-receiving element inspection method according to any one of claims 11 to 13, wherein the temperature dependence of the element characteristics of the back-incident type light-receiving element is measured by controlling the temperature of the back-incident type light-receiving element placed on the element placement portion using a temperature control element provided on the measurement stage.

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