Image generation apparatus and image generation method

An image generation apparatus is an image generation apparatus that generates an image based on measurement light from the semiconductor device, and the image generation apparatus includes an optical sensor that detects the measurement light, an optical sensor power supply that applies a constant voltage to the optical sensor to supply a current to the optical sensor, a current detector that generates a pattern signal according to magnitude of the current supplied to the optical sensor by the optical sensor power supply, and a control device that generates a pattern image based on the pattern signal.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an image generation apparatus and an image generation method.

Related Background Art

An optical probing technology called EOP (Electro Optical Probing) or EOFM (Electro-Optical Frequency Mapping) is known as a technology for testing a measurement target such as an integrated circuit (for example, see Patent Document 1). In the optical probing technology, the integrated circuit is irradiated with light emitted from a light source, measurement light (reflected light) from the integrated circuit is detected by an optical sensor, and a detection signal is acquired. Also, in the acquired detection signal, a desired frequency is selected, and amplitude energy of the signal is displayed over time. Or, image display is performed through two-dimensional mapping. Accordingly, it is possible to specify a position of a circuit operating at a desired frequency.

The optical probing technology described above can specify a failure place and a failure cause in a semiconductor device such as an integrated circuit. Here, in image display in the methods of Patent Document 1 described above, when an acquired detection signal of a photodetector is branched according to a desired frequency band to acquire a video image (pattern image) and a modulation image (EOFM image), an S/N ratio of their images may not be sufficiently high. Therefore, an object of the present invention is to provide an image generation apparatus and an image generation method in which improvement of an S/N ratio of an image is achieved.

SUMMARY OF THE INVENTION

An image generation apparatus according to an aspect of the present invention is an apparatus that generates an image based on light from the object, the image generation apparatus including: a photodetector that detects the light; a power supply unit that electrically couples the photodetector and applies a first constant voltage to the photodetector to supply a current to the photodetector; a signal generation unit that electrically couples the power supply unit and generates a first signal according to magnitude of the current supplied to the photodetector by the power supply unit; and an image processer that electrically couples the signal generation unit and generates a first image based on the first signal.

In this image generation apparatus, the constant voltage is applied and the current is supplied from the power supply unit to the photodetector. Thus, the current supplied from the power supply unit to the photodetector depends on the intensity of the light of the object. Also, since the first signal is generated based on the current and the first image is generated based on the first signal, the first image may depend on the intensity of the light of the object. Thus, since the image (the first image) according to the light of the object may be acquired without depending on the signal (detection signal) detected by the photodetector, for example, when two images according to the light of the object are desired to be acquired, one image can be acquired as the first image described above, and the other image can be acquired from the detection signal of the photodetector. For example, when the detection signal of the photodetector is branched according to a frequency band to acquire two images, an S/N ratio of the image may be degraded. In this regard, it is not necessary to branch the detection signal and it is possible to improve the S/N ratio of the image by acquiring the one image without depending on the detection signal of the photodetector, as in the image generation apparatus according to the present invention.

In the image generation apparatus according to the aspect of the present invention, the power supply unit may include a power supply that supplies a second voltage different from the first constant voltage; and a transformer that transforms the second voltage supplied from the power supply to the first constant voltage. By the predetermined voltage being transformed to the constant voltage in the power supply unit, it is possible to reliably generate the first signal and the first image according to the magnitude of the current supplied to the photodetector.

In the image generation apparatus according to the aspect of the present invention, the signal generation unit may measure the current flowing from the transformer to the photodetector to generate the first signal. Accordingly, it is possible to reliably measure the current supplied to the photodetector.

In the image generation apparatus according to the aspect of the present invention, the signal generation unit may include a first current detector that measures a current flowing through a wiring coupling the power supply to the transformer, and a second current detector that measures a current flowing through a wiring coupling the transformer to a ground potential line, and may measure a current supplied from the power supply to the photodetector to generate the first signal based on a difference between the current measured by the first current detector and the current measured by the second current detector. Since the difference between the current measured by the first current detector and the current measured by the second current detector and the current supplied from the power supply unit (more specifically, transformer) to the photodetector have a predetermined corresponding relationship, it is possible to reliably measure the current supplied from the power supply to the photodetector based on the above-described current difference.

In the image generation apparatus according to the aspect of the present invention, the transformer may be a DC/DC converter. Accordingly, it is possible to reliably perform transformation to a constant voltage.

In the image generation apparatus according to the aspect of the present invention, the object may be a semiconductor device. When the object is a semiconductor device, it is possible to effectively realize improvement of an S/N ratio of the image.

In the image generation apparatus according to the aspect of the present invention, a measurement unit that electrically couples the photodetector and measures at least one of a value indicating an in-phase component and a quadrature phase component, an amplitude, and a phase of a second signal output by the photodetector at a predetermined frequency or in a predetermined frequency band based on the second signal may be further included. Accordingly, it is possible to measure a parameter related to image generation from the second signal (detection signal) output by the photodetector.

In the image generation apparatus according to the aspect of the present invention, the image processer that generates a second image based on at least one of the value indicating an in-phase component and a quadrature phase component, the amplitude, and the phase of the second signal at the predetermined frequency or in the predetermined frequency band measured by the measurement unit may be further included. Accordingly, it is possible to generate a second image (for example, EOFM image) from the second signal. Therefore, it is possible to acquire the first image from the first signal and acquire the second image from the second signal.

In the image generation apparatus according to the aspect of the present invention, a display unit that displays a superimposed image that is superimposed the first image and the second image may be further included. Accordingly, for example, it is possible to acquire a superimposed image in which the first image is a pattern image and the second image is an EOFM image.

An image generation method according to an aspect of the present invention is an image generation method in which an image is generated based on light from the object, the image generation method including: applying a first constant voltage to a photodetector that detects the light, to supply a current to the photodetector; generating a first signal according to magnitude of the current supplied to the photodetector; and generating a first image based on the first signal.

In the image generation method according to the aspect of the present invention, the applying of the first constant voltage to supply the current may include supplying, by a power supply, a second voltage different from the first constant voltage; and transforming, by a transformer, the second voltage supplied from the power supply to the first constant voltage.

In the image generation method according to the aspect of the present invention, the generating of the first signal may include measuring the current flowing from the transformer to the photodetector to generate the first signal.

In the image generation method according to the aspect of the present invention, the generating of the first signal may include measuring, by a first current detector, a current flowing through a wiring coupling the power supply to the transformer; measuring, by a second current detector, a current flowing through a wiring coupling the transformer to a ground potential line, and measuring a current supplied from the power supply to the photodetector to generate the first signal based on a difference between the current measured by the first current detector and the current measured by the second current detector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described in detail with reference to the drawings. Further, the same portions or corresponding portions in the respective drawings are denoted with the reference numerals and repeated description will be omitted.

First Embodiment

An image generation apparatus1according a first embodiment is an apparatus for testing a semiconductor device2that is a measurement target and is a device under test (DUT), for example, specifying an abnormality occurrence place in the semiconductor device2, as illustrated inFIG. 1. The semiconductor device2includes an integrated circuit having a PN junction such as a transistor, for example, a small scale integration (SSI), a medium scale integration (MSI), a large scale integration (LSI), a very large scale integration (VLSI), an ultra large scale integration (VLSI), or a giga scale integration (GSI)), a MOS transistor and a bipolar transistor for high current/high voltage, or the like.

A tester unit17is electrically coupled to the semiconductor device2via a device control cable23. The tester unit17is operated by a power supply (not illustrated) and repeatedly applies a predetermined test signal (test pattern) to the semiconductor device2. Elements such as transistors formed in the semiconductor device2are driven by the test signal. Since various transistors are formed in the semiconductor device2, there is a plurality of driving frequencies according to a combination of ON/OFF of the respective transistors. Therefore, there is a plurality of modulation frequencies of measurement light (reflected light) from the semiconductor device2. The tester unit17may include a pulse generator. The tester unit17is electrically coupled to a spectrum analyzer16to be described below via a timing signal cable24.

The image generation apparatus1includes a laser light source3. The laser light source3is operated by a power supply (not illustrated) to generate and emit light with which the semiconductor device2is irradiated. The laser light source3is, for example, a lamp-based laser light source or a laser diode that generates laser light that is coherent light. The light emitted from the laser light source3is guided to a scan optical system6via a polarization preserving single-mode optical coupler4and a polarization preserving single-mode optical fiber5for probe light.

The scan optical system6includes a scan head7and a lens system8(for example, an objective lens) and is configured of, for example, a light scanning element such as a galvanometer mirror. The light guided to the scan head7is focused on the semiconductor device2by the lens system8. Accordingly, the light guided to the scan optical system6is imaged in a predetermined irradiation position of the semiconductor device2. The irradiation position of the light is two-dimensionally scanned with respect to the semiconductor device2by the scan optical system6. The irradiation position scanned by the scan optical system6is controlled by a laser scan controller9. The laser scan controller9is electrically coupled to the scan head7of the scan optical system6via the laser scan controller control cable19and to the laser light source3. The laser scan controller9designates, for example, the irradiation position with respect to the scan optical system6based on two-dimensional positional information indicated by a position (an x position and a y position) on orthogonal x and y axes. The laser scan controller9inputs the irradiation position indicated by the x position and the y position to a control unit10electrically coupled via a control cable22. Further, the respective components (scan head7and lens system8) of the scan optical system6, and the semiconductor device2are arranged in a dark box11.

Measurement light reflected by the semiconductor device2when the semiconductor device2is irradiated with the light emitted from the laser light source3is returned to the scan head7by the lens system8and guided to an optical sensor unit13via an optical fiber12for return light. The optical sensor unit13includes an optical sensor (photodetector)13athat detects the measurement light and outputs a detection signal (a second signal), and an optical sensor power supply (power supply unit)13bthat applies a constant voltage V2(a first constant voltage) to the optical sensor13ato supply a current I2, as illustrated inFIG. 2. The optical sensor13aand the optical sensor power supply13bare electrically coupled via an optical sensor power supply line13x. The optical sensor13aincludes, for example, a photodiode, an avalanche photodiode, a photomultiplier tube, an area image sensor, or the like.

The optical sensor power supply13bincludes a board power supply13c(power supply) that supplies a predetermined voltage (power), and a DC/DC converter13d(a transformation unit, a transformer) that receives the voltage supplied from the board power supply13c, as illustrated inFIG. 3. The board power supply13csupplies a predetermined voltage V1(a second voltage) to the DC/DC converter13d. For example, a switching regulator which is a voltage converter using a switching element, or a linear regulator which is a voltage comparator using a voltage current control element such as a transistor can be used as the DC/DC converter13d. The DC/DC converter13dconverts the voltage V1supplied from the board power supply13cto a constant voltage V2for the optical sensor13a, and applies the voltage V2to the optical sensor13ato supply the current I2to the optical sensor13a. Here, a driving state of the optical sensor13ais changed according to intensity of measurement light reflected by the semiconductor device2. Since the constant voltage V2is applied from the optical sensor power supply13bto the optical sensor13a, the current I2input to the optical sensor13ais changed according to the driving state of the optical sensor13a.

The DC/DC converter13dincludes, therein, a current detector (signal generation unit)50that measures the current I2supplied from the optical sensor power supply13bto the optical sensor13a. The current detector50electrically couples the optical sensor power supply13b. The current detector50measures the current I2supplied from the DC/DC converter13dto the optical sensor13aafter the transformation in the DC/DC converter13d. The current detector50generates a signal (a first signal) according to magnitude of the measured current I2. The signal is a signal used for generation of a pattern image in the control unit10(which may be hereinafter described as a pattern signal). Therefore, the current detector50converts magnitude of the measured current I2into the pattern signal. The pattern signal is, for example, a signal of a DC component or in a low frequency band. The pattern image is an image indicating a circuit pattern of the semiconductor device2and is an image indicating a scanning area in the scan optical system6(a scanning area image). Since a frequency of a change in the current is low, the pattern signal generated by the current detector50can be considered as being generated in a state in which a low pass filter is applied to the detection signal output from the optical sensor13a. The pattern signal generated by the current detector50is amplified by an amplifier81and output to the control unit10via a pattern signal line21. The current detector50includes a resistor, a Hall element, a current mirror circuit, a current transformer, or the like. Further, a wiring84via which the current I2is supplied from the DC/DC converter13dto the optical sensor13ais coupled to a ground potential line77via a capacitor83.

Referring back toFIG. 1, the detection signal output from the optical sensor unit13(more specifically, the optical sensor13a) is input to the spectrum analyzer16via an amplifier14and an AC (alternating current) amplifier15. The detection signal is used, for example, to generate an EOFM (electro optical frequency mapping) image, and is measured at a high frequency such as 10 kHz to 20 GHz. Further, the detection signal may be measured, for example, at a low frequency such as 10 KHz or lower. Further, the detection signal output from the optical sensor unit13is voltage-converted by a resistor13farranged at a subsequent stage of the optical sensor13a, amplified by an amplifier82, and output (seeFIG. 3).

The spectrum analyzer (measurement unit)16measures amplitude and a phase of the detection signal at a predetermined frequency or a predetermined frequency band based on the detection signal amplified by the AC amplifier15. More specifically, the spectrum analyzer16measures the amplitude and the phase of the detection signal for a reference frequency. The spectrum analyzer electrically couples the photodetector13a. Here, the reference frequency is a frequency of a reference signal that operates the spectrum analyzer16, and is a frequency of a synthesizer (a synthesizer built into the spectrum analyzer16) that becomes a time base of the spectrum analyzer16. That is, the spectrum analyzer16measures the phase of the detection signal for the frequency (reference frequency) of the built-in synthesizer. The reference frequency is set to a frequency (predetermined frequency) that is desired to be measured in the detection signal. Accordingly, the spectrum analyzer16can simultaneously measure the phase of the detection signal at the predetermined frequency and the amplitude of the detection signal at the predetermined frequency. Further, the spectrum analyzer16derives an IQ value at the predetermined frequency based on the phase and the amplitude of the detection signal at the predetermined frequency. I of the IQ value is “In-Phase” and indicates an in-phase component at the predetermined frequency. Further, “Q” is “Quadrature” and indicates a quadrature phase component at the predetermined frequency. An image obtained by mapping the in-phase component and the quadrature phase component of the detection signal to each irradiation position is an IQ image. Further, the spectrum analyzer16is electrically coupled to the tester unit17via a timing signal cable24. The spectrum analyzer16measures a phase of a test signal output from the tester unit17for the reference frequency, similarly to the detection signal described above. The spectrum analyzer16can obtain a phase difference between the detection signal and the test signal by synchronizing the reference frequency that is a reference at the time of the phase measurement of the detection signal described above with a reference frequency that is a reference at the time of the phase measurement of the test signal. The spectrum analyzer16outputs the phase, the amplitude and the IQ value to the control unit10at the predetermined frequency. Further, the optical sensor unit13and the amplifier14, the amplifier14and the AC amplifier15, the AC amplifier15and the spectrum analyzer16, and the spectrum analyzer16and the control unit10are electrically coupled to each other via a signal cable20. Further, such a spectrum analyzer is realized by a Cross Domain Analyzer (registered trademark), or a device that is a combination of two spectrum analyzers. Further, a device that measures the phase or the like of the detection signal is not limited to the spectrum analyzer such as the spectrum analyzer16, and various electrical measurement devices such as a lock-in amplifier or an oscilloscope may be used.

For example, the control unit10is a computer including at least a processor and a memory such as a PC. The control unit10controls each device of the image generation apparatus1. The control unit10including a processor functions as the first image generation unit (a image processer) that generates a pattern image at a predetermined frequency based on the pattern signal input by the current detector50. Further, the control unit10functions as a second image generation unit (the image processer) that generates an EOFM image based on at least one of the phase, the amplitude and the IQ value of the detection signal at the predetermined frequency input by the spectrum analyzer16. The EOFM image is an image of signal strength of a portion operating at a specific frequency. The control unit10generates a phase image at the predetermined frequency based on the irradiation position (x position and y position) of the scan optical system6input by the laser scan controller9and the phase of the detection signal at the predetermined frequency input by the spectrum analyzer16. Since the irradiation position is designated by the two-dimensional positional information as described above, it is possible to generate the phase image obtained by mapping the phase of the detection signal at the predetermined frequency to each irradiation position in a two-dimensional form. Similarly, the control unit10generates an amplitude image at the predetermined frequency through mapping to each irradiation position in the two-dimensional form based on the irradiation position (x position and y position) of the scan optical system6and the amplitude of the detection signal at the predetermined frequency. Similarly, the control unit10generates an IQ image at the predetermined frequency through mapping to each irradiation position in the two-dimensional form based on the irradiation position (x position and y position) of the scan optical system6and the IQ value of the detection signal at the predetermined frequency. The control unit10outputs the generated pattern image and the generated EOFM image to a display unit18electrically coupled via a display cable25. The display unit18displays a superimposed image in which the EOFM image and the pattern image input by the control unit10are superimposed.

Next, an operation and effects of the image generation apparatus1according to this embodiment will be described.

When failure analysis is conventionally performed by acquiring the EOFM image, the EOFM image is displayed to be superimposed on the pattern image of the semiconductor device instead of only the EOFM image being simply displayed, to thereby specifically specify a failure position. Since it is necessary for a superimposed image obtained by superimposing the images to be acquired without the EOFM image and the pattern image being misaligned, both the EOFM image and the pattern image are simultaneously acquired and generated from detection signals of the same optical sensors in order to prevent drift of a stage. In this case, the detection signal is branched in a frequency band by a branch circuit and, for example, a DC component (low frequency component) of the detection signal is used for generation of the pattern image, and an AC component (high frequency component) is used for generation of the EOFM image.

However, when the branch circuit is used, a change in the detection signal from the optical sensor is attenuated by the branch circuit, and when a change in the measurement light is small, an S/N ratio of the EOFM image may be degraded. Further, since a low frequency component and a high frequency component are separated by the branch circuit, low frequency sensitivity of the EOFM image generated based on an AC component (high frequency component) may be degraded. Further, the AC component may not be completely branched from a DC component (low frequency component) used for generation of the pattern image, and the AC component that is not branched may become a noise of the pattern image. Further, the branch circuit is a part in which the high frequency component is easily lost.

In this regard, in the image generation apparatus1according to this embodiment, the pattern signal used for generation of the pattern image is acquired without using the branch circuit as described above. Specifically, in the image generation apparatus1, the constant voltage V2is applied from the optical sensor power supply13bto the optical sensor13a, and the current I2is supplied to the optical sensor13a. Thus, the current I2supplied from the optical sensor power supply13bto the optical sensor13adepends on the intensity of the measurement light from the semiconductor device2. Also, since the pattern signal is generated based on the current I2and the pattern image is generated based on the pattern signal, the pattern image can depend on the intensity of the measurement light from the semiconductor device2. Thus, since the pattern image that is an image depending on the measurement light from the semiconductor device2can be acquired without depending on the detection signal of the optical sensor13a, for example, when the pattern image and the EOFM image are desired to be acquired as the images depending on the measurement light from the semiconductor device2, the pattern image can be acquired from the above-described pattern signal and the EOFM image can be acquired from the detection signal of the optical sensor13a. Thus, since the two images can be acquired without using the branch circuit, it is possible to improve the S/N ratio in comparison with a case in which the branch circuit is used. Further, there are no degradation of low frequency sensitivity of the EOFM image, generation of an AC component noise in the pattern image, and a loss of a high frequency component, which are problems when a frequency band is branched by the branch circuit to acquire the two images. Further, the configuration of the image generation apparatus is simplified by not using the branch circuit.

Further, the optical sensor power supply13bincludes the board power supply13cthat supplies the predetermined voltage V1, and the DC/DC converter13dthat transforms the predetermined voltage V1supplied from the board power supply13cinto the constant voltage V2. By the optical sensor power supply13btransforming the predetermined voltage V1into the constant voltage V2, it is possible to reliably generate the pattern signal and the pattern image according to the magnitude of the current I2supplied to the optical sensor13a.

Further, the current detector50measures the current I2supplied from the optical sensor power supply13bto the optical sensor13aand generates the pattern signal. Accordingly, it is possible to reliably measure the current supplied to the optical sensor13a.

Further, since the DC/DC converter13dis used as a transformation unit, it is possible to reliably perform transformation from the predetermined voltage V1to the constant voltage V2.

Further, since the measurement target is the semiconductor device2, it is possible to effectively achieve improvement of an S/N ratio of the image using the image generation apparatus1when the semiconductor device2is used.

Further, since the image generation apparatus1includes the spectrum analyzer16that measures at least one of the IQ value, the amplitude and the phase of the detection signal at the predetermined frequency or in the frequency band based on the detection signal output by the optical sensor13a, the image generation apparatus1can reliably measure a parameter related to the generation of the EOFM image from the detection signal output by the optical sensor13a.

Further, since the image generation apparatus1includes the control unit10that generates the EOFM image based on at least one of the IQ value, the amplitude, and the phase of the detection signal measured by the spectrum analyzer16, the image generation apparatus1can reliably generate the EOFM image from the detection signal.

Further, since the image generation apparatus1includes the display unit18that displays the pattern image and the EOFM image in a superimposing manner, the image generation apparatus1can acquire the superimposed image in which the pattern image and the EOFM image are superimposed.

Second Embodiment

Next, an image generation apparatus according to a second embodiment will be described with reference toFIG. 4. Further, a difference between the second embodiment and the first embodiment described above will be mainly described in a description according to the second embodiment.

FIG. 4is a diagram illustrating a current detector (signal generation unit)60and an optical sensor power supply33bin this embodiment. A difference between this embodiment and the first embodiment is that, in the first embodiment, the current detector50is arranged inside the DC/DC converter13dwhereas, in this embodiment, a current detector60is arranged outside a DC/DC converter33d(outside an optical sensor power supply33b) and a current I2flowing through a wiring65that couples the DC/DC converter33dto an optical sensor13ais measured, as illustrated inFIG. 4. The current detector60converts magnitude of the measured current I2into the pattern signal. With the current detector60arranged outside the DC/DC converter33din this way, the current supplied from the optical sensor power supply33bto the optical sensor13acan be reliably measured, similarly to the current detector50according to the first embodiment. Further, in the image generation apparatus according to this embodiment, a DC/DC converter (DC/DC converter33d) which does not include a current detector therein can be used.

Third Embodiment

Next, an image generation apparatus according to a third embodiment will be described with reference toFIG. 5. Further, a difference between the third embodiment and the first and second embodiments described above will be mainly described in the invention according to the third embodiment.

FIG. 5is a diagram illustrating a current detector (signal generation unit)70and an optical sensor power supply53bin this embodiment. The image generation apparatus according to this embodiment includes current detectors70aand70bas the current detector70, and a differential amplifier85, as illustrated inFIG. 5. The current detector (a first current detector)70ameasures a current I3flowing through a wiring75that couples the board power supply13cto the DC/DC converter33d. Further, the current detector (a second current detector)70bmeasures a current I4flowing through a wiring76that couples the DC/DC converter33dto the ground potential line77. The respective current detectors70aand70bare coupled to the differential amplifier85. A current I2is supplied from the DC/DC converter33dto the optical sensor13a, similarly to the first and second embodiments described above. Thus, the current I3flows to the DC/DC converter33d, and the current I4and the current I2flow from the DC/DC converter33d. Therefore, since a pattern signal corresponding to the current I3output from the current detector70aand a pattern signal corresponding to the current I4output from the current detector70bare input to the differential amplifier85, a pattern signal corresponding to the current I2flowing from the DC/DC converter33dto the optical sensor13a, which is obtained by subtracting the current I4from the current I3, is output. Further, a subtractor may be used in place of the differential amplifier85.

Thus, since a difference between the current I3flowing through the wiring75coupling the board power supply13cto the DC/DC converter33dand the current I4flowing through the wiring76coupling the DC/DC converter33dand the ground potential line77and the current I2flowing from the DC/DC converter33dto the optical sensor13ahave a predetermined corresponding relationship, it is possible to reliably measure the current I2flowing from the DC/DC converter33dto the optical sensor13abased on the current difference. The current detector70converts magnitude of the measured current I2into the pattern signal. Further, a DC/DC converter using a linear regulator is suitably used as the DC/DC converter33dof this embodiment.

While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the configuration that generates the light with which the semiconductor device is irradiated is not limited to the laser light source, and may be other light sources, such as an SLD (super luminescent diode), an ASE (amplified spontaneous emission), or an LED (light emitting diode) that generates incoherent light.

Further, while the detection signal output from the optical sensor unit has been described as being voltage-converted by a resistor, the configuration that voltage-converts the detection signal is not limited to the resistor and, for example, a transimpedance amplifier100as illustrated inFIG. 6may be used in place of the resistor. In the transimpedance amplifier100, a current I5input to an inverting input terminal103of an operational amplifier101is voltage-converted by a resistor105and output as a detection signal from an output terminal104of the operational amplifier101in a state in which a non-inverting input terminal102of the operational amplifier101is grounded.

Further, while the semiconductor device has been illustrated as the measurement target, the present invention is not limited thereto.