Apparatus and method for measuring sensitivity of light receiving element

Abstract

To provide a sensitivity measuring device and a sensitivity measuring method capable of measuring spectral sensitivity distribution of a light receiving element to be measured in a short time.SOLUTION: The sensitivity measurement device includes a light source, an optical system, a light collection mechanism, a position adjustment mechanism, a measurement unit, and an analysis unit. The optical system is configured to generate an interference wave by splitting light from a light source into two beams and causing the two beams to interfere with each other, and includes an optical path length difference changing mechanism configured to change an optical path length difference. The condensing mechanism condenses the interference wave at an irradiation position on the light receiving surface of the measured light receiving element. The position adjustment mechanism changes an irradiation position of the interference wave in a direction along the light receiving surface. The measurement unit controls the irradiation position and acquires a signal obtained by converting the interference wave from the light receiving element to be measured. The analysis unit calculates a component of the signal of each wavelength by Fourier transform of an interferogram obtained from the optical path length difference changed by the optical path length difference changing mechanism and the intensity of the signal measured by the measurement unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device and method for measuring the sensitivity of a light-receiving element. [Background technology]

[0002] There has been proposed a sensitivity measuring device that can measure both the spectral sensitivity distribution and the in-plane sensitivity distribution of a light-receiving element to be measured, such as a photodiode or a photocell. For example, the sensitivity measuring device described in Patent Document 1 includes an optical fiber that outputs light from a light source that outputs dispersed light toward the light-receiving element to be measured, and a mounting unit that movably mounts the light-receiving element to be measured. The sensitivity measuring device of Patent Document 1 controls the mounting unit and acquires a signal from the light-receiving element to be measured, thereby measuring not only the spectral sensitivity of the light-receiving element to be measured, but also the in-plane sensitivity distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-338857 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional light-receiving element spectral response measurement devices use a spectroscope to select the wavelength of light to irradiate the light-receiving element under test for light from a light source with a relatively wide wavelength range, such as a halogen lamp. Furthermore, a planar diffraction grating is used as the spectroscope, and the wavelength of light is changed by changing the angle at which this planar diffraction grating is positioned. Therefore, the time required to adjust the angle of the planar diffraction grating to switch the wavelength of light to be measured increases the measurement time, making this device unsuitable for measuring many samples.

[0005] Therefore, an object of the present invention, which has been made in view of these points, is to provide a sensitivity measuring apparatus and a sensitivity measuring method that can measure the spectral sensitivity distribution of a light-receiving element to be measured in a short time. [Means for solving the problem]

[0006] The present inventors have thoroughly investigated ways to solve the above-mentioned problems. They have concluded that the reason it takes so long to measure the spectral sensitivity distribution of a light-receiving element as described above is that the angle of the spectrometer must be physically changed every time the wavelength of the light to be measured is changed. Therefore, the present inventors have devised a spectral sensitivity measurement device for a light-receiving element that does not use a spectrometer. Specifically, the present inventors split light from a light source having a wavelength spread into two beams, change the optical path length difference between the two beams to cause interference, receive the interference waves with the light-receiving element to be measured, generate an interferogram, and perform a Fourier transform on this to calculate the signal intensity of each wavelength component. That is, the gist of the present invention is as follows:

[0007] (1) a light source; an optical system that divides an optical path through which light from the light source passes into a first optical path and a second optical path, and generates an interference wave by interfering the light from the light source that has passed through the first optical path and the second optical path, the optical system having an optical path length difference changing mechanism that changes an optical path length difference between the first optical path and the second optical path; a focusing mechanism for focusing the interference wave at an irradiation position on a light receiving surface of at least one light receiving element to be measured; a position adjustment mechanism that changes the irradiation position of the interference wave in a direction along the light-receiving surface of the at least one light-receiving element to be measured; a measurement unit that controls the irradiation position by the position adjustment mechanism and acquires a signal obtained by converting the interference wave received on the light-receiving surface from the at least one light-receiving element to be measured; an analysis unit that calculates the signal components of each wavelength by Fourier transform of an interferogram obtained from the optical path length difference between the first optical path and the second optical path changed by the optical path length difference change mechanism and the intensity of the signal measured by the measurement unit; and A device for measuring the sensitivity of a light receiving element.

[0008] (2) The sensitivity measuring device described in (1) above, wherein the at least one measured light receiving element is a plurality of light receiving elements provided on a wafer, and the position adjustment mechanism changes the irradiation position of the interference wave relative to the surface of the wafer.

[0009] (3) The position adjustment mechanism is further configured to change the focusing state of the interference wave on the light receiving surface of the at least one measured light receiving element, and the measurement unit is configured to control the focusing state in addition to the irradiation position using the position adjustment mechanism and to acquire the signal, in the sensitivity measurement device described in (1) or (2) above.

[0010] (4) A sensitivity measuring device described in any one of (1) to (3) above, wherein the position adjustment mechanism includes a mounting portion on which the measured light receiving element is mounted so as to be movable at least in a direction along the light receiving surface of the measured light receiving element.

[0011] (5) The sensitivity measuring device according to (3) above, wherein the position adjusting mechanism includes a focusing state adjusting mechanism that controls the focusing mechanism to change the focusing state of the interference wave.

[0012] (6) The sensitivity measuring device according to (5) above, wherein the focusing mechanism includes a lens, and the focusing state adjusting mechanism includes a lens position adjusting mechanism that moves the lens in a direction perpendicular to the light receiving surface.

[0013] (7) The sensitivity measuring device according to any one of (1) to (6) above, wherein the irradiation area of ​​the light receiving surface irradiated with the interference wave at the irradiation position is smaller than the area of ​​the light receiving surface.

[0014] (8) A sensitivity measuring device according to any one of (1) to (7) above, wherein the light receiving element to be measured has an optical filter on the light receiving surface, and the focusing mechanism irradiates the interference wave so that the maximum angle of incidence on the light receiving surface is 15 degrees or less.

[0015] (9) The sensitivity measuring device according to any one of (1) to (8) above, further comprising a camera for capturing an image of an area including the light receiving surface of the light receiving element to be measured.

[0016] (10) The sensitivity measuring device according to (9), wherein the measuring unit acquires an image from the camera and controls the irradiation position on the light receiving surface based on the image.

[0017] (11) The sensitivity measuring device according to (9) above, wherein the measuring unit acquires an image from the camera and controls the focusing mechanism based on the image so that the interference wave is focused at the irradiation position.

[0018] (12) The sensitivity measuring device described in (9) above, wherein the position adjustment mechanism includes a mounting section on which the measured light receiving element is movably mounted, and the measuring section acquires an image from the camera and, based on the image, controls the position of the mounting section in a direction perpendicular to the light receiving surface so that the interference wave is focused at the irradiation position.

[0019] (13) The sensitivity measuring device according to any one of (1) to (12) above, wherein the position adjustment mechanism has a tilt correction function for correcting the angle of incidence of the interference wave with respect to the light receiving surface at the irradiation position.

[0020] (14) The sensitivity measuring device described in (2) above, wherein the position adjustment mechanism includes a chuck that holds the wafer, and the chuck has a tilt correction function that corrects the angle of incidence of the interference wave with respect to the light receiving surface at the irradiation position.

[0021] (15) The sensitivity measuring device according to any one of (1) to (14) above, wherein the optical path length difference changing mechanism includes a movable mirror provided in the first optical path.

[0022] (16) Placing at least one light-receiving element to be measured on a mounting part that is movable in a direction along a light-receiving surface of the at least one light-receiving element to be measured; an optical system that splits light from a light source into a first optical path and a second optical path, and generates an interference wave by causing the light from the light source that has passed through the first optical path and the second optical path to interfere with each other, and that has an optical path length difference changing mechanism that changes the optical path length difference between the first optical path and the second optical path, and that focuses the light at an irradiation position on a light-receiving surface of the at least one light-receiving element to be measured via a focusing mechanism; controlling the irradiation position of the interference wave in a direction along the light receiving surface, and acquiring a signal obtained by converting the interference wave received on the light receiving surface from the at least one light receiving element to be measured; calculating the signal components of each wavelength by Fourier transform of an interferogram obtained from the optical path length difference between the first optical path and the second optical path changed by the optical path length difference changing mechanism and the intensity of the signal; A method for measuring the sensitivity of a light receiving element, comprising: [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a sensitivity measuring device and a sensitivity measuring method that can measure the spectral sensitivity distribution of a light-receiving element to be measured in a short time. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a block diagram showing a schematic configuration of a light-receiving element sensitivity measuring device according to an embodiment; [Figure 2] FIG. 2 is an enlarged view of the dashed line portion of FIG. 1. [Figure 3] 10 is a diagram showing an example of the relationship between the size of an irradiation area where an interference wave irradiates a light-receiving surface and the size of an area of ​​the light-receiving surface when the object of sensitivity measurement includes a light-receiving element array. FIG. [Figure 4] FIG. 2 is a block diagram showing a schematic configuration of an analysis unit in FIG. 1. [Figure 5] FIG. 2 is a diagram showing an example of an interferogram generated by the analysis unit of FIG. 1. [Figure 6] 2 is a graph of signal components of each wavelength calculated by Fourier transform in the analysis unit of FIG. 1. [Figure 7]10A and 10B are graphs showing signal components of each wavelength when the angle of incidence of an interference wave on a light receiving element is different. [Figure 8] 1 is a flowchart illustrating a method for measuring the sensitivity of a light receiving element according to an embodiment. [Figure 9] 10 is a diagram illustrating a position adjustment mechanism when the light-receiving element to be measured is a photodiode with a metal can package. FIG. [Figure 10] 10A and 10B are diagrams illustrating a position adjustment mechanism when the light receiving element to be measured is an array of a plurality of light receiving elements provided on a wafer before dicing. DETAILED DESCRIPTION OF THE INVENTION

[0025] In the past, when manufacturing photodetectors, it was sufficient to test the photosensitivity of the photodetector to monochromatic light, and there was little need to test the spectral sensitivity. However, in recent years, higher performance has been required of photodetectors, such as those equipped with optical filters. Accordingly, it has become necessary for the transmission characteristics of a specific wavelength range of the optical filter to match the wavelength range to be used in a sensor, etc., and there has been an increasing need to test the spectral sensitivity of the photodetector. The present invention provides a measurement device and a measurement method capable of measuring the spectral sensitivity of a large number of photodetectors or a wafer on which photodetectors are arranged continuously in a short period of time.

[0026] An embodiment of the present invention will be described below with reference to the drawings. Note that the embodiment described below is specifically described to allow a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[0027] [Overall configuration of the photodetector sensitivity measurement device] As shown in FIG. 1, a sensitivity measuring device 1 for a light receiving element according to one embodiment of the present invention includes a light source 11, an interference optical system 12, a lens 13, a mounting section 15 on which a light receiving element 14 to be measured is placed, a camera 16, a measuring section 17, and an analyzing section 18.

[0028] (light source) The light source 11 emits light having a continuous wavelength range. The light source 11 emits light in a wavelength range that includes the operating wavelength range of the light-receiving element 14 to be measured. The light source 11 may be selected depending on the operating wavelength range of the light-receiving element 14 to be measured. For example, a halogen lamp capable of emitting light in a wavelength range of approximately 350 nm to 3500 nm may be used as the light source 11. The light source 11 is not limited to a halogen lamp and may also be a tungsten lamp, an ASE (Amplified Spontaneous Emission) light source, an LED (Light Emitting Diode), a supercontinuum light source, or the like. The light source 11 may include a collimating lens and be configured to emit collimated light to the interference optical system 12. Note that in FIG. 1, the chief ray of the light emitted from the light source 11 and passing through the lens 13 is represented by an arrow.

[0029] (Interference optical system) In one embodiment, the interference optical system 12 has an optical system similar to that of a Michelson interferometer. The interference optical system 12 is an optical system including a half mirror 21, a movable mirror 22, and a fixed mirror 23. Each component of the interference optical system 12 will be described below.

[0030] The half mirror 21 is an optical element that splits incident light from the light source 11 into transmitted light and reflected light. The half mirror 21 is also called a beam splitter. In one embodiment, the half mirror 21 is positioned so that the angle of incidence of light 24 from the light source 11 is 45° and the intensities of the transmitted light and reflected light are approximately equal. The half mirror 21 splits the optical path along which the light 24 from the light source 11 travels into a first optical path 25 and a second optical path 26. For example, as shown in FIG. 1 , the first optical path 25 includes an optical path that transmits through the half mirror 21, is reflected by the movable mirror 22, and is then reflected by the half mirror 21. The second optical path 26 includes an optical path that is reflected by the half mirror 21, is reflected by the fixed mirror 23, and is then transmitted through the half mirror 21. The light that has traveled through the first optical path 25 and the light that has traveled through the second optical path 26 are combined by the half mirror 21 and interfere with each other to generate an interference wave 27.

[0031] The movable mirror 22 is a plane mirror disposed on the first optical path 25 so as to be movable in a direction along the first optical path 25. The movable mirror 22 functions as an optical path length difference changing mechanism that changes the optical path length difference between the first optical path 25 and the second optical path 26. The movable mirror 22 includes a movable mirror drive mechanism 22a for driving the movable mirror 22. The movable mirror drive mechanism 22a may include a stepping motor or the like that controls the position of the movable mirror 22 with high precision. The movable mirror drive mechanism 22a is connected to the analysis unit 18 by one or more signal lines. The movable mirror drive mechanism 22 may move the movable mirror 22 based on a signal from the analysis unit 18. The movable mirror drive mechanism 22 may also transmit position information of the movable mirror 22 to the analysis unit 18. The fixed mirror 23 is a plane mirror fixedly disposed on the second optical path 26. By moving the movable mirror 22, the optical path length difference between the first optical path 25 and the second optical path 26 changes. This also changes the intensity of the interference wave 27. Since the interference optical system 12 has the movable mirror 22, the difference in optical path length between the first optical path 25 and the second optical path 26 can be easily adjusted with a simple configuration.

[0032] 1 is merely an example. The first optical path 25 may be arranged on the side where the light 24 from the light source 11 is reflected by the half mirror 21, rather than on the side where the light 24 from the light source 11 is transmitted through the half mirror 21. The second optical path 26 may be arranged on the side where the light 24 from the light source 11 is transmitted through the half mirror 21, rather than on the side where the light 24 from the light source 11 is reflected by the half mirror 21. The half mirror 21 may be replaced with a cube-shaped beam splitter.

[0033] The movable mirror 22 is not limited to a plane mirror. The movable mirror 22 may be a retroreflector that reflects incident light in a direction parallel to and opposite to the incident direction. The movable mirror 22 is not limited to a mirror that can move in a direction along the first optical path 25 in order to adjust the optical path length difference. The movable mirror 22 may be movable in a movement direction that has a component along the first optical path 25. The first optical path 25 and the second optical path 26 may have movable mirrors that can move in both, rather than just one of them. The two movable mirrors may be configured to move in conjunction with each other.

[0034] The interference optical system 12 can have various configurations other than those described above. The interference optical system 12 may utilize various interferometer optical systems, such as a Fabry-Perot interferometer or a Fizeau interferometer. In either case, the interference optical system 12 divides the optical path through which light from the light source passes into a first optical path 25 and a second optical path 26. The first optical path 25 and the second optical path 26 do not necessarily need to be spatially separated, and some of the optical paths may be parallel and overlap. The interference optical system 12 may have any type of optical path length difference changing mechanism that changes the optical path length difference between the first optical path 25 and the second optical path 26.

[0035] (measurement system) Fig. 2 is an enlarged view of the portion of the measurement system indicated by the dashed line in Fig. 1. The measurement system includes a lens 13, a mounting unit 15 on which at least one light-receiving element 14 to be measured is placed, a camera 16, and a measurement unit 17.

[0036] <Light collection mechanism> The lens 13 constitutes a focusing mechanism that focuses the interference wave 27, which is incident as parallel light, at an irradiation position on the light-receiving surface 14a of the light-receiving element 14 to be measured. The lens 13 is, for example, a single convex lens. The lens 13 may also be a combination of multiple lenses. The focusing mechanism may also include, instead of the lens 13, a concave mirror or other optical element with a focusing function arranged on the optical path of the interference wave 27. The focusing mechanism may also be configured by combining multiple types of optical elements including mirrors and lenses. The focusing mechanism may further include a focusing state adjustment mechanism that adjusts the focusing state of the interference wave 27. The focusing state adjustment mechanism may control the position, attitude, shape, and / or optical characteristics of some or all of the optical elements that constitute the focusing mechanism.

[0037] In FIG. 2, when the area where the interference wave 27 irradiates the light-receiving surface 14a is assumed to be a circular area, its diameter is shown as the irradiation diameter φ. The smaller the irradiation diameter φ, the better. To narrow the irradiation diameter φ, the larger the numerical aperture of the lens 13. However, if the light-receiving element 14 to be measured has an optical filter on the light-receiving surface 14a, a deviation in the spectral sensitivity obtained from the measurement results will occur if the maximum incident angle θ of the interference wave 27 with respect to the light-receiving surface 14a becomes large. Therefore, the lens 13 is configured to irradiate the interference wave 27 so that the maximum incident angle θ with respect to the light-receiving surface 14a is 15 degrees or less. This is because if the maximum incident angle θ is within 15 degrees, there will be no significant deviation in the spectral sensitivity obtained from the measurement results. This point will be discussed further below.

[0038] <Photodetector under test> The light-receiving element 14 to be measured is a light-receiving element that is the object of measurement by the sensitivity measurement device 1. A single light-receiving element 14 to be measured may be placed on the mounting part 15, or a measurement object such as a wafer or semiconductor chip on which the light-receiving elements 14 to be measured are arranged in an array may be placed. An example of the structure of the light-receiving element 14 to be measured is shown in a cross-sectional view in Figure 2.

[0039] The light-receiving element 14 to be measured is a PIN-type photodiode including a light-receiving surface 14a, a first electrode 14b, and a second electrode 14c. When the first electrode 14b is connected to a p-type semiconductor layer, when light is irradiated onto the light-receiving surface 14a of the light-receiving element 14 to be measured, a current flows from the second electrode 14c to the first electrode 14b according to the principle of a PIN-type photodiode. The light-receiving element 14 to be measured may have various configurations other than those described above. For example, the light-receiving element 14 to be measured may be a PN-type photodiode or an avalanche-type photodiode. Furthermore, in addition to a top- and bottom-electrode structure, a two-electrode top-surface and two-electrode bottom-surface structure (i.e., a flip chip) may also be used.

[0040] The first electrode 14b and the second electrode 14c of the light-receiving element 14 under measurement are connected to the measuring unit 17 via a signal line. During measurement, the light-receiving element 14 under measurement may be reverse biased via the signal line, or may be in a state where no bias is applied (0 V). When a reverse bias is applied, a negative voltage is applied to the first electrode 14b on the p-type semiconductor layer side, and a positive voltage is applied to the second electrode 14c on the n-type semiconductor layer side. The light-receiving element 14 under measurement converts the interference wave 27 received through the light-receiving surface 14a into an electrical signal and outputs it to the measuring unit 17. In one embodiment, the electrical signal is a current. The measuring unit 17 measures the electrical signal obtained from the light-receiving element 14 under measurement. A circuit connected to a load resistor or a circuit connected to an operational amplifier may be used to measure the electrical signal.

[0041] Depending on the application, the measured light receiving element 14 may be provided with an optical filter that transmits light of a specific wavelength band on the incident side of the light receiving surface 14a of the interference wave 27. The optical filter can be a known filter depending on the application, such as a dielectric multilayer film. The optical filter is not limited to this, and may be, for example, an absorption filter that absorbs wavelengths outside the desired wavelength range. The dielectric multilayer film can be made of a low-refractive index / high-refractive index combination, such as SiO2 / α-Si (amorphous silicon), Al2O3 / α-Si, SiO2 / Si3N4, Si3N4 / α-Si, SiO2 / Ta2O5, or Ta2O5 / α-Si. The measured light receiving element 14 with an optical filter on the light receiving surface 14a side can be used in sensors for various applications. Examples of sensors that use the measured light receiving element 14 include a time-of-flight (TOF) sensor module, a CO2 sensor, or a CH4 sensor.

[0042] In this embodiment, the plane along the light receiving surface 14a is defined as the xy plane. The xy plane is a plane including two directions, the x direction and the y direction. The direction perpendicular to the light receiving surface 14a is defined as the z direction. The xy plane can be a plane parallel to the upper surface of the mounting portion 15. The z direction can be a direction parallel to the optical axis O of the interference wave 27. The xy plane can be a horizontal plane, but is not limited to this. The z direction can be a vertical direction, but is not limited to this.

[0043] <Mounting section (position adjustment mechanism)> The mounting portion 15 is, for example, a plate-like member having a circular or rectangular shape when viewed from above. The mounting portion 15 can mount a single light-receiving element 14 to be measured or a measurement object (e.g., a wafer or semiconductor chip) including a plurality of light-receiving elements 14 to be measured arranged in an array. The mounting portion 15 may include a fixing mechanism for fixing the single light-receiving element 14 to be measured or the measurement object including a plurality of light-receiving elements to be measured. The fixing mechanism may have a shape for accommodating the light-receiving element 14 to be measured or the measurement object, and a mechanical structure for fixing and holding them. By having the mounting portion 15, the light-receiving element 14 to be measured can be stably held in a predetermined position.

[0044] The mounting unit 15 includes a mounting unit position adjustment mechanism 15a. The mounting unit position adjustment mechanism 15a drives the mounting unit 15 in a direction along the xy plane to adjust the position of the light-receiving element 14 to be measured in the x and y directions. Therefore, the mounting unit 15 functions as a position adjustment mechanism that changes the irradiation position of the interference wave 27 in a direction along the light-receiving surface 14a of the light-receiving element 14 to be measured. The mounting unit position adjustment mechanism 15a is connected to the measurement unit 17 by one or more signal lines. The mounting unit position adjustment mechanism 15a may move the mounting unit 15 based on a signal from the measurement unit 17. The mounting unit position adjustment mechanism 15a moves the light-receiving element 14 to be measured while it is mounted on the mounting unit 15, thereby enabling stable and accurate adjustment of the position of the light-receiving element 14 to be measured.

[0045] The method for realizing the position adjustment mechanism is not limited to the method of moving the mounting unit 15 in the xy plane direction relative to the optical axis O of the interference wave 27. For example, the method for realizing the position adjustment mechanism may include moving the interference optical system 12 and the lens 13 together relative to the mounting unit 15, and / or providing an optical system on the optical path of the interference wave 27 that shifts the interference wave 27 in the xy plane direction.

[0046] The mount unit 15 may further have a tilt correction function that corrects the incident angle of the interference wave 27 relative to the light-receiving surface 14a at the irradiation position. The mount unit position adjustment mechanism 15a can adjust the tilt angle of the mount unit 15 so that the optical axis O of the interference wave 27 is perpendicular to the light-receiving surface 14a. Therefore, the mount unit position adjustment mechanism 15a may be capable of adjusting the angle around two axes included in the horizontal plane of the mount unit 15, for example, around the x-axis and the y-axis. The tilt adjustment function may be realized by a tilt adjustment mechanism different from the mount unit position adjustment mechanism 15a. The tilt correction function allows the central light ray of the interference wave 27 to be perpendicularly incident on the light-receiving surface 14a, thereby improving measurement accuracy. Furthermore, the tilt correction function eliminates or reduces the need to adjust the focusing position of the interference wave 27 in the z-direction each time the light-receiving element 14 to be measured is changed when measuring a measurement target having multiple light-receiving elements 14 to be measured. Therefore, by having the tilt correction function, it is possible to quickly measure a plurality of light-receiving elements 14 to be measured.

[0047] <Camera> Camera 16 has an imaging element and an imaging optical system. Camera 16 can capture light with a wavelength corresponding to the wavelength range of light source 11. For example, if light source 11 emits light with a wavelength in the visible light range, camera 16 can capture an image in the visible light wavelength range. If light source 11 emits light with a wavelength in the near-infrared region, camera 16 can capture an image in the near-infrared region wavelength range.

[0048] The camera 16 directs the optical axis of the imaging optical system toward the light-receiving surface 14a of the light-receiving element 14 to capture an image of the position where the interference wave 27 is irradiated on the light-receiving surface 14a. The imaging optical system of the camera 16 can magnify and capture the light-receiving surface. The camera 16 is capable of capturing images at high magnification, and when the subject includes an array of many fine light-receiving elements 14 to be measured, it can capture the light-receiving surface 14a of each of the light-receiving elements 14 to be measured. The camera 16 may be able to capture both the entire array of the light-receiving elements 14 to be measured and each individual light-receiving element 14 to be measured by changing the magnification of the imaging optical system.

[0049] Camera 16 is connected to measurement unit 17 via one or more signal lines. Camera 16 captures images by changing the imaging magnification based on signals from measurement unit 17. Camera 16 transmits the captured images to measurement unit 17 via the signal lines.

[0050] <Lens position adjustment mechanism (position adjustment mechanism)> The sensitivity measurement device 1 further includes a lens position adjustment mechanism 19 that moves the lens 13 in the z direction to change the focusing state of the interference wave 27 on the light-receiving surface 14a. The lens position adjustment mechanism 19 is included in the focusing state adjustment mechanism. For example, the lens 13 may be held by a holder, and the lens position adjustment mechanism 19 may include a motor that drives the holder in the z direction. By moving the lens 13 in the z direction, the focusing position of the interference wave 27 also moves in the z direction. By adjusting the position of the lens 13 in the z direction, the size of the irradiation area of ​​the interference wave 27 on the light-receiving surface 14a can be adjusted to be minimized. The lens position adjustment mechanism 19 moves the focusing position of the interference wave 27 on the light-receiving surface 14a of the light-receiving element 14 to change the focusing state, and is therefore included in the position adjustment mechanism. By controlling the focusing state of the interference wave 27 and focusing the interference wave 27 on the light-receiving surface 14a, the accuracy of the signal detected by the light-receiving element 14 to be measured is improved.

[0051] The lens position adjustment mechanism 19 is connected to the measurement unit 17 by one or more signal lines. The lens position adjustment mechanism 19 moves the position of the lens 13 in the z direction based on a signal from the measurement unit 17. The measurement unit 17 may control the lens position adjustment mechanism 19 based on an image acquired from the camera 16 so that the irradiation area of ​​the interference wave 27 on the light receiving surface 14a is minimized.

[0052] The focusing state of the interference wave 27 can also be changed by the mount position adjustment mechanism 15a moving the mount 15 in the z direction. That is, the mount position adjustment mechanism 15a may be able to move the mount 15 in the z direction in addition to moving it in the x and y directions. The measurement unit 17 may acquire an image from the camera 16 and, based on the image, control the position of the mount 15 in the z direction perpendicular to the light receiving surface 14a so that the interference wave 27 is focused at the irradiation position. In this case, the lens position adjustment mechanism 19 may not be provided.

[0053] <Measurement section> The measurement unit 17 includes at least one processor, at least one dedicated circuit, or a combination thereof. The processor may be a general-purpose processor such as a central processing unit (CPU) or a graphics processing unit (GPU), or a dedicated processor specialized for a specific process. The dedicated circuit may be, for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). The measurement unit 17 may include a memory unit including semiconductor memory including random access memory (RAM) and read-only memory (ROM), magnetic memory, and / or optical memory. The measurement unit 17 further includes an input / output interface for transmitting and receiving information to and from the light-receiving element 14, the mounting unit position adjustment mechanism 15a, the camera 16, and the lens position adjustment mechanism 19 via signal lines. The measurement unit 17 can measure the light-receiving element 14 according to a program stored in the memory unit.

[0054] For example, assume that the measurement target is a light-receiving element array 28 (see FIG. 3 ) including multiple light-receiving elements 14 to be measured. The measurement unit 17 sequentially measures each of the light-receiving elements 14 to be measured included in the light-receiving element array 28. To achieve this, the measurement unit 17 acquires an image of the light-receiving element array 28 mounted on the mounting unit 15 from the camera 16. After identifying the light-receiving element 14 to be measured, the measurement unit 17 drives the mounting unit position adjustment mechanism 15 a to position the light-receiving element 14 to be measured at the center of the image captured by the camera 16. The measurement unit 17 then increases the image magnification of the camera 16 to acquire an enlarged image of the identified light-receiving element 14 to be measured, as shown in the right diagram of FIG. 3 . The measurement unit 17 then drives the mounting unit position adjustment mechanism 15 a to align the light-receiving surface 14 a of the light-receiving element 14 to an irradiation area 29 of the interference wave 27. The irradiation area 29 is smaller than the area of ​​the light-receiving surface 14 a. This makes it easier to control the light-collecting state using the lens position adjustment mechanism 19. Also, because all interference waves 27 are incident on a single light-receiving element 14 under measurement, the spectral sensitivities of all light-receiving elements 14 under measurement can be compared under the same conditions. Furthermore, the measurement unit 17 controls the position of the lens 13 in the z direction using the lens position adjustment mechanism 19 to minimize the irradiation diameter φ of the irradiation area 29 of the interference wave 27 on the light-receiving element 14, thereby adjusting the interference wave 27 to be collected at the irradiation position on the light-receiving surface 14a. Note that although the light-receiving surface 14a of the light-receiving element 14 under measurement is shown as a square in FIG. 3, the shape of the light-receiving surface 14a is not limited to a square and may be any shape. Furthermore, the shape of the irradiation area 29 is not limited to a circle and may be any shape.

[0055] When the adjustment of the mounting portion position adjustment mechanism 15a and the lens position adjustment mechanism 19 is completed, the measurement unit 17 acquires an electrical signal obtained by converting the interference wave 27 received by the light-receiving surface 14a from the light-receiving element 14 to be measured. The measurement unit 17 and the analysis unit 18 are connected by one or more signal lines. The measurement unit 17 transmits information on the signal strength of the electrical signal acquired from the light-receiving element 14 to the analysis unit 18 via the signal line.

[0056] (Analysis Department) The analysis unit 18 controls the overall processing executed by the sensitivity measurement apparatus 1, and analyzes information obtained by measurement by the measurement unit 17 to calculate the spectral sensitivity of the light-receiving element 14 to be measured. The analysis unit 18 may be a general-purpose computer such as a PC (Personal Computer) or a workstation, or a computer dedicated to the sensitivity measurement apparatus 1. The analysis unit 18 and the measurement unit 17 may not be separate devices, but may be the same device. As shown in FIG. 4 , the analysis unit 18 includes a control unit 31, an acquisition unit 32, a calculation unit 33, a storage unit 34, an input unit 35, and an output unit 36.

[0057] Like the measurement unit 17, the control unit 31 includes at least one processor, at least one dedicated circuit, or a combination of these. The control unit 31 controls each unit of the analysis unit 18 and also controls the overall operation of the sensitivity measurement device 1. In particular, the control unit 31 can control the operation of the movable mirror drive mechanism 22a. For example, the control unit 31 may control the movable mirror drive mechanism 22a so that the movable mirror 22 repeatedly moves back and forth within a predetermined range.

[0058] The acquiring unit 32 sequentially acquires information on the intensity of the electrical signal of the interference wave 27 measured by the measuring unit 17. The acquiring unit 32 also acquires position information of the movable mirror 22 from the movable mirror drive mechanism 22a. Alternatively, the position information of the movable mirror 22 may be calculated within the control unit 31 from control information with which the control unit 31 operates the movable mirror drive mechanism 22a.

[0059] The calculation unit 33 includes at least one processor, at least one dedicated circuit, or a combination of these, similar to the control unit 31. The hardware of the calculation unit 33 may be common to the hardware of the control unit 31. Alternatively, the calculation unit 33 may have a dedicated processor or dedicated circuit specialized for a specific calculation.

[0060] The storage unit 34 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The semiconductor memory is, for example, a RAM or a ROM. The RAM includes, for example, a static random access memory (SRAM) or a dynamic random access memory (DRAM). The ROM includes, for example, an electrically erasable programmable read only memory (EEPROM). The storage unit 34 functions as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 34 stores programs and data used in the operation of the analysis unit 18, as well as data obtained by the operation of the analysis unit 18. The storage unit 34 may store in advance spectral distribution information of the light emitted from the light source 11.

[0061] The input unit 35 includes at least one input interface. The input interface may be, for example, a physical key such as a keyboard, a capacitance key, a pointing device, or a touch screen integrated with a display. The input interface may also be, for example, a microphone for receiving voice input, a camera for receiving image input, or the like. The input unit 35 receives instructions for the analysis unit 18 and operations for inputting data used in the operation of the analysis unit 18. For example, a user of the sensitivity measurement device 1 may adjust each component of the sensitivity measurement device 1 and instruct the start and end of measurement via the input unit 35. The input unit 35 may be connected to the analysis unit 18 as an external input device instead of being provided in the analysis unit 18.

[0062] The output unit 36 ​​includes at least one output interface. The output interface is, for example, a display that outputs information visually, or a speaker that outputs information audibly. The display is, for example, a liquid crystal display or an organic EL display. The output unit 36 ​​outputs data acquired from the measurement unit 17, data analyzed by the analysis unit 18, etc. The output unit 36 ​​may be connected to the analysis unit 18 as an external output device instead of being provided in the analysis unit 18.

[0063] Next, we will explain the processing content of the calculation unit 33. The calculation unit 33 can calculate the optical path length difference between the first optical path 25 and the second optical path 26 at each time point based on the position information of the movable mirror 22.

[0064] Furthermore, the calculation unit 33 generates an interferogram from the calculated optical path length difference at each time point and the signal intensity measured by the measurement unit 17. As shown in FIG. 5, the interferogram is expressed as a graph with the optical path length difference on the horizontal axis and the signal light intensity on the vertical axis. The interferogram shows a composite waveform resulting from the simultaneous interference of light of each wavelength component. When the optical path length difference is 0, the light of all wavelength components constructively interacts with each other, so the interferogram has a strong peak at the position where the optical path length difference is 0.

[0065] Next, the calculation unit 33 performs a Fourier transform on the generated interferogram to output the signal components of each wavelength. As an example, the output of the Fourier transform based on an assumed example is shown in FIG. 6. The calculation unit 33 can calculate the sensitivity of each wavelength of the measured light-receiving element 14, i.e., the spectral sensitivity distribution, from the output signal components of each wavelength and the intensity of each wavelength of the light emitted from the light source 11 (i.e., the spectral intensity distribution). The calculation unit 33 can output the calculated spectral sensitivity distribution of the measured light-receiving element 14 to the output unit 36.

[0066] FIG. 7 is a graph showing the sensitivity of each wavelength component when the incident angle of the interference wave 27 on the light-receiving surface 14a is changed for a light-receiving element 14 under test, which has an optical filter on the light-receiving surface 14a side. The symbols 0°, 5°, 10°, etc. indicate the graphs for incident angles of 0°, 5°, 10°, etc. The graphs for incident angles of 5°, 10°, and 15° almost overlap with the graph for an incident angle of 0°, showing no significant difference. However, for incident angles of 30° and 45°, the graphs are significantly shifted toward shorter wavelengths due to the characteristics of the optical filter. Therefore, when the incident angle of the interference wave 27 incident on the light-receiving surface 14a includes components exceeding 15°, the shape of the graph showing the sensitivity of each generated wavelength will be shifted from the graph showing the sensitivity of each wavelength when the incident angle is 0°. Therefore, it is preferable that the maximum incident angle θ at which the interference wave 27 is incident on the light-receiving surface 14a shown in FIG. 2 is 15° or less.

[0067] With the configuration as described above, the sensitivity measurement device 1 according to one embodiment can measure the spectral sensitivity of the light-receiving element 14 to be measured in a short time without changing the position of the spectrometer for a plurality of wavelengths and performing measurements for each wavelength. Furthermore, the sensitivity measurement device 1 is particularly effective in fields such as sensors that are provided with an optical filter on the light-receiving surface 14a and require that the wavelength band to be measured by the light-receiving element 14 and the transmission wavelength band of the optical filter match with high accuracy.

[0068] [Method for measuring the light receiving sensitivity of a photodetector] The flowchart in Fig. 8 shows the procedure for measuring the spectral sensitivity of the light-receiving element 14 to be measured using the sensitivity measurement device 1. The processing of the flowchart in Fig. 8 may be executed, for example, by the control unit 31 of the analysis unit 18 using each component of the sensitivity measurement device 1. A part or all of the flowchart in Fig. 8 may be executed by the control unit 31 in accordance with a program stored in the storage unit 34. The procedure for measuring the spectral sensitivity of the light-receiving element 14 to be measured will be described below with reference to Fig. 8.

[0069] A single light-receiving element 14 to be measured or a measurement object including one or more light-receiving elements 14 to be measured is placed on the mounting unit 15 (step S101). The procedure for placing the light-receiving element 14 to be measured or the measurement object on the mounting unit 15 may be mechanized and / or automated. For example, the light-receiving element 14 to be measured or the measurement object may be mounted on the mounting unit 15 from a storage space provided outside the sensitivity measurement device 1 using a dedicated handler. The handler is a device that transports the light-receiving element 14 to be measured or a measurement object including one or more light-receiving elements 14 to be measured to the mounting unit 15 and places or attaches or removes the light-receiving element 14 to be measured or moves it outside the sensitivity measurement device 1.

[0070] Next, the light source 11 is driven, and the light from the light source 11 is made to interfere with the light using the interference optical system 12, and the interference wave 27 is irradiated onto the light-receiving element 14 to be measured (step S102). The light source 11 may be activated upon receiving an activation signal from the measurement unit 17 or the analysis unit 18.

[0071] The measurement unit 17 acquires the irradiation position of the interference wave 27 on the light-receiving element 14 to be measured and the size of the irradiation area 29, i.e., the condensed state, from an image of the light-receiving surface 14a of the light-receiving element 14 to be measured taken by the camera 16. The measurement unit 17 operates the mounting part position adjustment mechanism 15a and the lens position adjustment mechanism 19 based on the irradiation position and condensed state of the interference wave 27, and controls the irradiation position of the interference wave 27 in the x and y directions and the condensed position in the z direction to be appropriate positions (step S103).

[0072] The measurement unit 17 performs a measurement start process for the single light-receiving element 14 under measurement (step S104). The measurement start process may include electrically connecting the first electrode 14b and the second electrode 14c to a measurement data input terminal of the measurement unit 17. For example, the sensitivity measurement device 1 may have a probe connected to the measurement unit 17 by a signal line, and may be configured to bring the tip of the probe into contact with the first electrode 14b at the start of measurement. The mounting unit 15 may have an electrode on its upper surface connected to the measurement unit 17 by a signal line, and may be configured such that the second electrode 14c is electrically connected to the measurement unit 17 when the light-receiving element 14 under measurement is placed on the mounting unit 15. Furthermore, the measurement start process may include applying a reverse bias voltage to the light-receiving element 14 under measurement. By applying the reverse bias voltage, the light-receiving element 14 under measurement has a faster response speed and generates an electrical signal proportional to the intensity of the interference wave 27 it receives.

[0073] The analyzing unit 18 controls the movable mirror driving mechanism 22a to start the operation of the movable mirror 22 (step S105). For example, the movable mirror 22 may move from a position where the optical path length of the first optical path 25 is equal to that of the second optical path 26 to a position where the optical path length of the first optical path 25 is longer than the optical path length of the second optical path 26 by a predetermined length. For example, the movable mirror 22 may make one or more reciprocating movements while measuring a single light-receiving element 14 to be measured. Note that step S105 may start at any time between steps S101 and S104, rather than after step S104, and the movable mirror 22 may move repeatedly thereafter.

[0074] The light-receiving element 14 to be measured converts the received interference wave 27 into an electrical signal. The measuring unit 17 acquires this electrical signal in time series from the light-receiving element 14 to be measured (step S106). The measuring unit 17 sequentially transmits information on the signal strength of the acquired electrical signal to the analyzing unit 18. The analyzing unit 18 may store the information on the signal strength together with time information in the storage unit 34.

[0075] When the analysis unit 18 acquires a series of signal intensity information for the light-receiving element 14 to be measured from the measurement unit 17, the analysis unit 18 associates time information at each measurement point with information on the optical path length difference between the first optical path 25 and the second optical path 26. The analysis unit 18 associates the optical path length difference between the first optical path 25 and the second optical path 26 with the intensity of the signal acquired from the measurement unit 17 to generate an interferogram (step S107). The analysis unit 18 may store the generated interferogram in the storage unit 34.

[0076] The analysis unit 18 calculates the signal intensity for each wavelength, i.e., the spectral intensity distribution, by Fourier transforming the interferogram generated in step S108 (step S108). The analysis unit 18 may store the calculated signal components for each wavelength in the storage unit 34.

[0077] The analysis unit 18 calculates the sensitivity of each wavelength of the light receiving element 14 to be measured, i.e., the spectral sensitivity distribution, using information on the signal intensity of each wavelength of light emitted from the light source 11 stored in the storage unit 34 (step S109). For example, the analysis unit 18 calculates the ratio of the signal intensity of each wavelength of the light receiving element 14 to the intensity of light of each wavelength emitted from the light source 11. The analysis unit 18 may store the calculated information on the sensitivity of each wavelength of the light receiving element 14 to be measured in the storage unit 34. If the light source 11 emits light with a substantially constant intensity in the wavelength range in which the light receiving element 14 to be measured operates, step S109 does not need to be executed. In this case, the signal component for each wavelength calculated in step S108 indicates the relative sensitivity of the light receiving element 14 to each wavelength.

[0078] When the measurement of a single light-receiving element 14 to be measured is completed, the measurement unit 17 performs a measurement termination process for the light-receiving element 14 to be measured (step S110). The measurement termination process includes, for example, stopping the light emission of the light source 11, stopping the application of the bias voltage, and disconnecting the first electrode 14b and the second electrode 14c from the measurement data input terminal of the measurement unit 17.

[0079] Next, the analysis unit 18 determines whether there is an unmeasured light-receiving element 14 to be measured on the mounting unit 15 (step S111). For example, if the measurement target is a semiconductor chip or wafer including an array of multiple light-receiving elements 14 to be measured, the analysis unit 18 sequentially measures each of the light-receiving elements 14 to be measured. If there is an unmeasured light-receiving element 14 to be measured (step S111: Yes), the process executed by the analysis unit 18 returns to step S102, and the next light-receiving element 14 to be measured is measured.

[0080] If there is no unmeasured light-receiving element 14 to be measured in step S111 (step S111: No), the light-receiving element 14 to be measured is released from the mounting section 15 (step S112). The light-receiving element 14 to be measured or the measurement object including an array of multiple light-receiving elements 14 to be measured is released from the mounting section 15 and moved by the handler to the outside of the sensitivity measurement device 1, and the measurement ends. Note that if there are multiple measurement objects mounted with the light-receiving element 14 to be measured and multiple light-receiving elements 14 to be measured, the processes from step S101 to S112 may be executed sequentially for each light-receiving element 14 to be measured or each measurement object.

[0081] In another embodiment, the processes from steps S107 to S109 executed by the analysis unit 18 do not have to be executed during measurement of the light-receiving element 14 to be measured, i.e., between steps S106 and S110. The processes from steps S107 to S109 may be executed after step S112. The processes from steps S107 to S109 may be executed collectively for multiple light-receiving elements 14 to be measured.

[0082] As described above, the sensitivity measurement apparatus 1 of the present invention has an interference optical system 12 that splits light 24 from a light source 11 into a first optical path 25 and a second optical path 26 and generates an interference wave by causing the light to interfere. The sensitivity measurement apparatus 1 generates an interferogram from the optical path length difference between the first optical path 25 and the second optical path 26 and the signal intensity obtained by converting the interference wave at the light-receiving element 14 to be measured. Furthermore, the sensitivity measurement apparatus 1 calculates the signal component of each wavelength by Fourier transforming the generated interferogram. Therefore, in the present invention, there is no need to perform measurements for each wavelength while sequentially moving the spectrometer, and measurements can be completed in a short time.

[0083] For example, when the present inventors measured the signal intensity distribution for each wavelength for a single light receiving element 14 using a conventional spectrometer, it took four minutes per light receiving element. When the present inventors measured the signal intensity distribution for each wavelength for the same light receiving element 14 using the sensitivity measurement device 1 of the present invention, they were able to complete the measurement in one to two seconds per light receiving element. Therefore, the present invention is expected to shorten the measurement time by two orders of magnitude.

[0084] [Example of a photodetector to be measured] In the present invention, the photodetector 14 to be measured includes a single photodiode, a photodetector included in a semiconductor chip on which a large number of photodetectors are arranged, and a photodetector on a wafer before dicing on which a large number of photodetectors are arranged on the surface.

[0085] FIG. 9 shows a method for mounting a photodiode 41 with a metal can package on the mounting section 15 when the light-receiving element 14 to be measured is a photodiode 41 with a metal can package. While FIG. 9 shows only some of the components, the sensitivity measurement device 1 includes other components similar to those in FIG. 1. Hereinafter, the photodiode 41 with a metal can package will be referred to simply as a photodiode 41. Each photodiode 41 has two pins 41a and 41b. A plurality of photodiodes 41 are stored in a storage space 42 for measurement. Each photodiode 41 is sequentially transported to the mounting section 15 by a handler 43 and undergoes sensitivity measurement. In FIG. 9, the handler 43 is simply indicated by a double-headed arrow.

[0086] The mounting section 15 may have a hole for accommodating the pins 41a and 41b of the photodiode 41. Signal lines connected to the measurement section 17 pass through the hole, and when the pins 41a and 41b are accommodated in the hole, the pins 41a and 41b come into contact with the signal lines, respectively. This enables measurement of the sensitivity of the photodiode 41. The mounting section 15 may be configured so that one or more photodiodes 41 can be mounted at a time. When the photodiode 41 is mounted on the mounting section 15, tilt may occur depending on the mounting state. For this reason, the mounting section 15 may have a tilt correction function.

[0087] 9, the sensitivity measurement device 1 also includes a position adjustment mechanism configured to change the irradiation position of the interference wave 27 on the light receiving surface 14a of the photodiode 41 by using the mounting part 15, and to control the focusing state of the interference wave on the surface of the mounting part 15. Specifically, the sensitivity measurement device 1 may include a mounting part position adjustment mechanism 15a that moves the mounting part 15 in the x and y directions, and a lens position adjustment mechanism 19 that adjusts the position in the z direction of the lens 13 that focuses the interference wave 27. This makes it possible to sequentially measure a plurality of photodiodes 41 using the sensitivity measurement device 1 of the present invention.

[0088] 10 shows a case where the light receiving element 14 to be measured is a plurality of light receiving elements provided on a wafer 45 before dicing. A plurality of wafers 45 are stored in a storage space 42 to be measured. Each wafer 45 is sequentially transferred by a handler 43 to a chuck 46, which is a mounting unit 15, and undergoes sensitivity measurement. Although FIG. 10 shows only some of the components, the sensitivity measurement device 1 includes other components similar to those in FIG. 1.

[0089] The chuck 46 secures and holds the wafer 45 on its upper portion. The chuck 46 has, for example, a vacuum mechanism 47 for suctioning the wafer. The vacuum mechanism 47 may include a number of holes for suctioning the wafer provided in the chuck 46. By vacuuming these holes and suctioning the wafer 45, even if the wafer 45 is warped or deflected, it can be measured in a flat state. The chuck 46 may have an inclination correction function to correct the angle of incidence of the interference wave 27 with respect to the wafer surface at the irradiation position. The wafer surface is equal to the light-receiving surface 14a of each light-receiving element 14 to be measured formed on the wafer 45. This allows the interference wave 27 to be incident perpendicularly to the surface of the wafer 45.

[0090] 10, the sensitivity measurement device 1 also includes a position adjustment mechanism configured to change the irradiation position of the interference wave 27 on the surface of the wafer 45 by using the chuck 46, and to control the focusing state of the interference wave 27 on the surface of the wafer 45. Specifically, the sensitivity measurement device 1 may include a mounting part position adjustment mechanism 15a that moves the chuck 46 in the x and y directions, and a lens position adjustment mechanism 19 that adjusts the position in the z direction of the lens 13 that focuses the interference wave 27.

[0091] The measurement unit 17 has a probe 48 connected to an input terminal of the measurement unit 17. The measurement unit 17 connects electrodes formed on the underside of the wafer 45 to other input terminals. The measurement unit 17 can acquire an output signal from the light-receiving element 14 to be measured by bringing the probe 48 into contact with an electrode of the light-receiving element 14 to be measured formed on the upper part of the wafer 45. This makes it possible to sequentially measure each light-receiving element 14 to be measured on the wafer 45 using the sensitivity measurement device 1 of the present invention.

[0092] In the above embodiment, information processing was performed by the measurement unit 17 and the analysis unit 18. The processing performed by the measurement unit 17 and the analysis unit 18 may be executed by a single piece of hardware, or may be executed by two or more pieces of hardware with arbitrary functional division.

[0093] In the above embodiment, the movable mirror drive mechanism 22a is controlled by the analysis unit 18. However, the movable mirror drive mechanism 22a may be controlled by the measurement unit 17. In this case, the measurement unit 17 performs processing during measurement of the light-receiving element 14 to be measured, and the analysis unit 18 performs processing to analyze the data acquired by the measurement unit 17 after the measurement is completed, so that the functions may be divided. In this case, the analysis unit 18 does not need to be located in the same place as the measurement unit 17 and other components of the sensitivity measurement device 1. The analysis unit 18 may be located in a remote location via a communication line. Furthermore, the functions of the analysis unit 18 may be executed in a distributed manner by multiple computers rather than by a single computer.

[0094] Although the embodiments of the present invention have been described based on the drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications and alterations based on the present invention. Therefore, it should be noted that these modifications and alterations are within the scope of the present invention. For example, functions included in each component or step can be rearranged so as not to be logically inconsistent, and multiple components or steps can be combined or divided into one. Although the embodiments of the present invention have been described mainly in terms of an apparatus, the embodiments of the present invention can also be realized as a method including steps executed by each component of the apparatus. The embodiments of the present invention can also be realized as a method, a program, or a storage medium having a program recorded thereon executed by a processor provided in the apparatus. It should be understood that these are also encompassed within the scope of the present invention.

[0095] In the present invention, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In the configurations distinguished by descriptions such as "first" and "second" in the present invention, the numbers in the configurations can be exchanged. For example, the first optical path can exchange the identifiers "first" and "second" with the second optical path. The exchange of identifiers is performed simultaneously. The configurations remain distinguished even after the identifier exchange. Identifiers may be deleted. A configuration from which an identifier has been deleted is distinguished by a symbol. The descriptions of identifiers such as "first" and "second" in the present invention should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a smaller number.

[0096] In the present invention, the x-direction, y-direction, and z-direction are provided for the convenience of explanation and may be interchanged. The configuration according to the present invention has been described using an orthogonal coordinate system formed by the x-direction, y-direction, and z-direction. The positional relationship between the components according to the present invention is not limited to an orthogonal relationship. [Industrial Applicability]

[0097] The present invention can be applied to a sensitivity measuring device and a sensitivity measuring method for a light receiving element. [Explanation of symbols]

[0098] 1 Sensitivity measurement device 11 Light source 12 Interference optical system (optical system) 13 Lens (light-collecting mechanism) 14. Light receiving element to be measured 14a Photosensitive surface 15 Mounting section (position adjustment mechanism) 15a Mounting part position adjustment mechanism 16 Camera 17 Measuring part 18 Analysis Department 19 Lens position adjustment mechanism (light focusing state adjustment mechanism, position adjustment mechanism) 21 Half Mirror 22 Moving mirror (optical path length difference change mechanism) 22a Moving mirror drive mechanism 23 Fixed mirror 24 Light from a source 25 1st optical path 26 Second optical path 27 Interference Waves 28 Photodetector array 29 Irradiation area 41 (Metal can packaged) Photodiode 42 storage space 43 Handler 45 Zipper 46 wafers 47 (for wafer suction) pressure reduction mechanism 48 probes

Claims

1. A light source and an optical system that divides an optical path through which light from the light source passes into a first optical path and a second optical path, and generates an interference wave by interfering the light from the light source that has passed through the first optical path and the second optical path, the optical system having an optical path length difference changing mechanism that changes an optical path length difference between the first optical path and the second optical path; a focusing mechanism for focusing the interference wave at an irradiation position on a light receiving surface of at least one light receiving element to be measured; a position adjustment mechanism that changes the irradiation position of the interference wave in a direction along the light-receiving surface of the at least one light-receiving element to be measured; a measurement unit that controls the irradiation position by the position adjustment mechanism and acquires a signal obtained by converting the interference wave received on the light-receiving surface from the at least one light-receiving element to be measured; an analysis unit that calculates the signal components of each wavelength by Fourier transform of an interferogram obtained from the optical path length difference between the first optical path and the second optical path changed by the optical path length difference change mechanism and the intensity of the signal measured by the measurement unit; and A device for measuring the sensitivity of a light receiving element.

2. 2. The sensitivity measuring device according to claim 1, wherein the at least one light receiving element to be measured is a plurality of light receiving elements provided on a wafer, and the position adjusting mechanism changes the irradiation position of the interference wave with respect to the surface of the wafer.

3. 2. The sensitivity measuring device of claim 1, wherein the position adjustment mechanism is further configured to change the focusing state of the interference wave on the light receiving surface of the at least one measured light receiving element, and the measurement unit is configured to control the focusing state in addition to the irradiation position using the position adjustment mechanism and to acquire the signal.

4. 2. The sensitivity measuring device according to claim 1, wherein the position adjusting mechanism includes a mounting portion on which the light receiving element to be measured is mounted so as to be movable at least in a direction along the light receiving surface of the light receiving element to be measured.

5. 4. The sensitivity measurement device according to claim 3, wherein the position adjustment mechanism includes a focusing state adjustment mechanism that controls the focusing mechanism to change the focusing state of the interference wave.

6. 6. The sensitivity measurement device according to claim 5, wherein the light-collecting mechanism includes a lens, and the light-collecting state adjusting mechanism includes a lens position adjusting mechanism that moves the lens in a direction perpendicular to the light-receiving surface.

7. 2. The sensitivity measuring device according to claim 1, wherein an irradiation area of ​​the light receiving surface irradiated with the interference wave at the irradiation position is smaller than an area of ​​the light receiving surface.

8. 2. The sensitivity measurement device according to claim 1, wherein the light receiving element to be measured has an optical filter on the light receiving surface, and the light collecting mechanism irradiates the interference wave so that the maximum incident angle with respect to the light receiving surface is 15 degrees or less.

9. 2. The sensitivity measuring device according to claim 1, further comprising a camera for capturing an image of an area including the light-receiving surface of the light-receiving element to be measured.

10. 10. The sensitivity measuring device according to claim 9, wherein the measuring section acquires an image from the camera and controls the irradiation position on the light receiving surface based on the image.

11. 10. The sensitivity measurement device according to claim 9, wherein the measurement unit acquires an image from the camera and controls the focusing mechanism based on the image so that the interference wave is focused at the irradiation position.

12. The sensitivity measuring device of claim 9, wherein the position adjustment mechanism includes a mounting section on which the measured light receiving element is movably mounted, and the measuring section acquires an image from the camera and, based on the image, controls the position of the mounting section in a direction perpendicular to the light receiving surface so that the interference wave is focused at the irradiation position.

13. 2. The sensitivity measuring device according to claim 1, wherein the position adjusting mechanism has a tilt correction function for correcting an incident angle of the interference wave with respect to the light receiving surface at the irradiation position.

14. 3. The sensitivity measuring device according to claim 2, wherein the position adjustment mechanism includes a chuck for holding the wafer, the chuck having a tilt correction function for correcting an incident angle of the interference wave with respect to the light receiving surface at the irradiation position.

15. 2. The sensitivity measuring device according to claim 1, wherein the optical path length difference changing mechanism includes a movable mirror provided in the first optical path.

16. placing at least one light-receiving element to be measured on a mounting portion that is movable in a direction along a light-receiving surface of the at least one light-receiving element to be measured; an optical system that splits light from a light source into a first optical path and a second optical path, and generates an interference wave by causing the light from the light source that has passed through the first optical path and the second optical path to interfere with each other, and that focuses the light at an irradiation position on a light-receiving surface of the at least one light-receiving element to be measured via an optical system having an optical path length difference changing mechanism that changes the optical path length difference between the first optical path and the second optical path, and a focusing mechanism; controlling the irradiation position of the interference wave in a direction along the light receiving surface, and acquiring a signal obtained by converting the interference wave received on the light receiving surface from the at least one light receiving element to be measured; calculating the signal components of each wavelength by Fourier transform of an interferogram obtained from the optical path length difference between the first optical path and the second optical path changed by the optical path length difference changing mechanism and the intensity of the signal; A method for measuring the sensitivity of a light receiving element, comprising:

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