WO2016170589A1

WO2016170589A1 - Surface current vector measurement system and failure diagnosis system using same

Info

Publication number: WO2016170589A1
Application number: PCT/JP2015/062028
Authority: WO
Inventors: 諭村岡; 久亮金井; 李　ウェン
Original assignee: 株式会社日立製作所
Priority date: 2015-04-21
Filing date: 2015-04-21
Publication date: 2016-10-27

Abstract

Provided is a failure diagnosis system for industrial and medical devices that has a low cost and is easy to install. This failure diagnosis system is configured so as to be provided with a surface current vector measurement system for measuring the strength of the magnetic field generated by the current flowing through a control board of a device to be diagnosed, memory for storing the surface current vector distribution data for the device to be diagnosed acquired by the surface current vector measurement system during normal operation, a comparison unit for comparing the saved data in the memory and the surface current vector distribution data acquired by the surface current vector measurement system, and a failure diagnosis unit for determining that there is a failure in the device to be diagnosed if the difference data per surface current vector compared by the comparison unit exceeds a prescribed threshold.

Description

Surface current vector measurement system and fault diagnosis system using the same

The present invention relates to a surface current vector measurement system and an electronic device failure diagnosis system using the same.

A scanning electron beam type semiconductor inspection and measurement device for inspecting and measuring the shape of a wiring pattern formed on a semiconductor wafer is installed in a vacuum housing, an acceleration electrode for accelerating an electron beam, an electron beam diameter A sample on the stage is irradiated with an electron beam through a plurality of electrodes, such as a plurality of diaphragm electrodes for focusing and a plurality of deflection electrodes for adjusting the irradiation position of the electron beam, and secondary electrons and reflected electrons from the sample are irradiated. Is detected, and the wiring pattern shape is inspected and measured. Also, in a scanning electron beam type drawing apparatus for forming a wiring pattern on a semiconductor wafer, similarly, by irradiating a resist laminated on the semiconductor wafer with an electron beam through a plurality of electrodes, A wiring pattern is formed. As described above, in the semiconductor manufacturing apparatus and the semiconductor inspection / measurement apparatus, electrodes for controlling a plurality of charged particle beams are provided, and a plurality of control boards for controlling each electrode are mounted.

If these control boards fail, the measurement accuracy and formation pattern accuracy are reduced, the semiconductor wafer is destroyed, and the opportunity is lost due to the stop of the production line. Therefore, it is required to identify the failure point and perform maintenance at an early stage.

There is a technique described in Japanese Patent No. 5461799 (Patent Document 1) as a method for detecting a failure location of a charged particle beam drawing apparatus.

On the other hand, as a method for measuring the current and the electromagnetic field generated therewith, the consumption described in Japanese Patent Application Laid-Open No. 2012-44001 (Patent Document 2) and “Measurement of Electromagnetic Field and Visualization thereof” (Non-Patent Document 1) There is a technique for detecting a change in electric current and an electromagnetic field associated therewith. When a circuit is opened due to a failure of a current consumption element or a connector is not properly fitted, or a circuit board wiring is short-circuited, a current different from that during normal operation flows in the power supply circuit. The occurrence of this abnormal current is observed to detect a faulty part of the device.

Japanese Patent No. 5461799 JP 2012-42401 A

When the electromagnetic field distribution measuring method described in Patent Document 1 is applied to a drawing apparatus equipped with a DAC amplifier unit that does not have a circuit diagnosis function, it is necessary to replace all the DAC amplifier units, resulting in high cost. It will take. Further, it is necessary to stop the apparatus in order to replace the DAC amplifier unit.

On the other hand, the electromagnetic field distribution measuring method described in Patent Document 2 measures an electromagnetic field of a substrate inside a device or a control unit, and an electromagnetic field corresponding to the electromagnetic field at a place where the electromagnetic field is measured. It realizes that a vector is grasped three-dimensionally. In this case, since the electromagnetic field around the internal substrate and the control device is measured, it is considered that the fluctuation of the electromagnetic field due to the current inside the apparatus can be monitored without stopping the apparatus.

However, the current fluctuation of the power supply circuit that occurs at the time of failure occurs not only in the substrate and power supply device inside the device but also in the device external casing connected to the external ground. There is a possibility that a system for detecting an abnormality can be provided by measuring the current flowing through the casing and comparing it with a current measurement value obtained under normal conditions.

The housing of the device has a structure with irregularities such as a cylindrical shape and a protruding portion of a cable connector in addition to a flat surface. The conventional electromagnetic field measurement has a problem that an error occurs in the magnetic field measurement value and the measurement coordinate depending on the attitude of the magnetic field probe.

Since the strength of the magnetic field generated by the current on the surface of the conductor is inversely proportional to the square of the distance, it is possible to measure a smaller magnetic field if the magnetic field sensor is close to the housing surface. If the magnetic field sensor is separated from the housing surface, it is necessary to calibrate the magnetic field measurement value by measuring the distance. In addition, when the coil cross section and the case surface vertical match, the magnetic flux interlinking with the coil cross section is maximized, the voltage generated at both ends of the coil is maximized, and when the coil cross section and the case surface are parallel, the voltage at both ends is minimized. Become. Thus, when the angle between the coil cross section in the magnetic field probe and the vertical axis of the housing surface is different, the magnetic field intensity to be measured is also different, and calibration of the magnetic field measurement is necessary. When the rotation angle about the vertical axis of the sensor housing surface changes, the magnetic flux linked to the coil cross section changes, so the magnetic field measurement value needs to be calibrated.

As described above, in order to measure the magnetic field generated by the current on the surface of the apparatus housing, the angle between the magnetic field probe and the vertical surface of the housing, the distance from the housing surface, and the vertical axis of the housing surface are used as axes. There is a problem of accurately grasping the rotation angle and calibrating magnetic field measurement values and measurement coordinates.

In view of the above problems, the present application enables measurement by avoiding obstacles such as large devices such as trains, curved housings, cables attached to the devices, and by inserting sensors in narrow places. A failure diagnosis system that can be applied to an existing apparatus without stopping the system is provided.

In order to solve the above problems, the present invention provides a surface current vector measurement system for measuring a magnetic field generated based on a surface current flowing through a measurement object, a coil for measuring the magnetic flux density of the magnetic field, and detecting the position and orientation of the probe. A surface current measurement probe comprising a position / posture sensor that performs amplification and an amplifier that amplifies the output signal of the coil, and a position of the probe and a position vector orientation information, and a measurement coil cross section vector and a measurement target housing surface vertical vector, And a surface current vector calculating unit that calculates the surface current vector from the corrected magnetic flux density by correcting the magnetic flux density by the angle θ.

In order to solve the above problem, in the present invention, in the surface current vector measurement system, the surface current vector calculation unit includes a case surface vertical vector based on position information of the probe and case surface information of the measurement target. The angle θ between the measurement coil cross-section vector and the measurement target case surface vertical vector is calculated from the posture information of the probe, and the magnetic field measurement data measured by the probe is corrected by the angle θ to obtain the magnetic flux density. And the surface current vector is calculated from the corrected magnetic flux density.

In order to solve the above problems, in the present invention, a failure diagnosis system is obtained by a surface current vector measurement system that measures the magnetic field intensity generated by a current flowing from a control board of a diagnosis target device, and the surface current vector measurement system. A memory for storing the distribution data of the surface current vector during normal operation of the device to be diagnosed, a comparison unit for comparing the storage data of the memory and the distribution data of the surface current vector obtained by the surface current vector measurement system; And a failure diagnosing unit that determines that the diagnosis target device is faulty when the difference data in units of surface current vectors compared by the comparing unit exceeds a predetermined threshold value.

In order to solve the above-mentioned problem, in the present invention, in the fault diagnosis system, a monitor is further connected via an external interface, and the fault diagnosis unit is a surface current measured by the surface current vector measurement system at the time of diagnosis. The surface current vector I at the probe position P on the scanning path on the surface of the case of the diagnosis target device displayed in three dimensions and on the surface of the case of the diagnosis target device displayed in a two-dimensional development view. (f) was configured to be displayed on the monitor.

According to the present invention, the error due to the position / orientation information of the magnetic field sensor is calibrated to provide a high-precision magnetic field measurement means, which is attached to a large apparatus such as a train, a casing having unevenness and a curved surface, and an apparatus. Therefore, it is possible to provide a fault diagnosis system that can be applied to an existing apparatus without stopping the apparatus. It can be realized at low cost, can be installed without stopping the device, and can detect a failure of the device or the control board.

It is a figure which shows the structure of the failure diagnosis system which is the 1st Embodiment of this invention. It is a figure which shows an example of a structure of the surface current measurement probe provided with the position and attitude | position detection function. It is a figure explaining the process of the surface current vector calculation part of a surface current vector measurement system. Is a diagram for explaining a method of calculating a housing surface perpendicular vector X in the probe position _{_{P (x 1, y 1,}} z 1). The distribution of the surface current vector on the housing surface of the diagnosis target device measured by the surface current vector measurement system is displayed in (A) three-dimensional display and (B) two-dimensional development view to identify and display abnormal vectors and fault locations. It is a figure explaining the function of a failure diagnosis system. It is a flowchart explaining the failure diagnosis process of the failure diagnosis system of 1st Embodiment. It is a figure which shows an example of a structure of the surface current measurement probe provided with the position and attitude | position detection function of 2nd Embodiment. It is a figure explaining the process of the surface current vector calculation part of the surface current vector measurement system of 2nd Embodiment. It is a figure explaining the scanning electron microscope to which a failure diagnosis system is applied. It is a figure explaining the vehicle to which a failure diagnosis system is applied.

The following embodiments have been described in sufficient detail for those skilled in the art to practice the present invention, but other implementations and forms are possible and depart from the scope and spirit of the technical idea of the present invention. It is possible to change the structure and structure and replace various elements.

FIG. 1 shows a configuration of a failure diagnosis system 100 according to the first embodiment of the present invention. The failure diagnosis system 100 includes, for example, a failure diagnosis device 120 configured on one substrate or a single device configuration and a monitor 108 connected to an external interface 109.

The failure diagnosis apparatus 120 includes a surface current vector measurement system 101 that measures a surface current flowing through a casing of a diagnosis target apparatus or a control board in the apparatus, and the surface current vector measurement system 101. Memory 103 for storing the distribution data 110 of the surface current vector acquired at the timing of setting the initial state to the initial state (the timing at which the device to be diagnosed can be regarded as operating normally), the storage data of the memory 103, and the A crest value comparison unit 104 that compares crest values with the distribution data 110 of the surface current vector acquired at an arbitrary timing for diagnosing the diagnosis target device acquired by the surface current vector measurement system 101, and a frequency characteristic that compares the frequency characteristics Comparison of angle of surface current vector with comparison unit 105 and comparison of surface current vector angle And 106, the comparison data outputted from the respective comparator unit is configured to include a fault diagnosis unit 107 for outputting a diagnostic result to determine the fault state of the control board of the diagnosis target device or the apparatus.

Further, the surface current vector measuring system 101 is connected to the surface current measuring probe 200 by, for example, a cable 111 and taken out to the surface of the casing of the target device for failure diagnosis or a control board in the device. It is configured to be able to scan the vicinity. The surface current measurement probe 200 detects a magnetic field generated due to the surface current flowing on the surface of the casing of the device to be diagnosed or a control board mounted in the device. The surface current vector distribution data 110 is calculated by the surface current vector calculation unit 102 based on the detected magnetic field measurement data.

Examples of the surface current measurement probe 200 include a method using a magnetic field measurement probe of a loop coil or a flux gate sensor. The loop coil is a method of measuring a magnetic field and a current from a voltage induced at both ends of a coil, which is composed of a conductive wire formed in a loop shape and changes with time in the magnetic flux interlinking with the loop.

The fluxgate sensor is composed of a magnetic core, an excitation coil wound around the magnetic core, and a detection coil. An AC magnetic field with a magnitude that causes the magnetic core to be magnetically saturated is applied by the excitation coil. This is a method of measuring a magnetic field and a current from a voltage induced in the.

Since the loop coil is a method of measuring a magnetic field from an induced voltage generated in proportion to a time change of the flux linkage, there is a possibility that the detection sensitivity to a low frequency magnetic field of several Hz to several tens Hz or less may be lowered. . Further, since the fluxgate sensor uses a magnetic material having a high magnetic permeability, the frequency characteristic of the magnetic material is a rate-determining condition, and the sensitivity is greatly reduced for a magnetic field of several tens of kHz or more.

A surface current vector measurement system using a magnetic field measurement probe of a loop coil or a fluxgate sensor can achieve the effect of the present invention. However, in order to improve the fault diagnosis accuracy of the control board, the surface current measurement probe is used in a wide band. It is very useful to increase the sensitivity.

FIG. 2 shows an example of the configuration of a surface current measurement probe 200 having a position / posture detection function. The probe includes a coil 201 in the current probe, an analog amplifier 211 that amplifies an output signal of the coil, and a position / posture sensor 206 that outputs probe position / posture information 210. The coil 201 includes, for example, a flux gate sensor, a loop coil, a Hall element, and other sensors that can detect a magnetic field according to the minimum frequency of measurement. Further, an A / D converter for converting the output signal of the amplifier 211 into a digital signal and a digital signal processing means 208 are provided.
The surface current measurement probe 200 outputs magnetic field measurement data 209 converted into a digital signal by an A / D converter and digital signal processing means 208, and probe position / posture information 210.

The surface current vector calculation unit 102 receives the output of the surface current measurement probe 200 and uses the position information (CAD data or the like) of the housing surface 202 of the diagnosis target device that is separately prepared, and uses the housing surface vertical vector 203. And a distance 204 between the housing surface and the surface current measurement probe, and a vector 205 of the cross section of the magnetic field measurement coil 201 in the current probe, and a magnetic field measurement coil cross section vector 205 in the current probe An angle θ207 formed with the casing surface vertical vector 203 is calculated. Subsequently, calibration calculation of the magnetic field measurement data 209 that is the output of the surface current measurement probe 200 is performed.

FIG. 3 illustrates the processing of the surface current vector calculation unit 102 of the surface current vector measurement system 101.

In step S101, it calculates the casing surface vertical vector 203 of the probe position output from the position and orientation sensor 206 coordinate P _{0 (previously} determined representative points P _R representing the position of the probe.).
First, as shown in FIG. 4, a probe position P (x ₁ , y ₁ , z ₁ ) 401 is obtained by mapping the probe position coordinates P ₀ onto the housing surface 402 by using a 3D CAD or a digital still camera. Is calculated. Next, with respect to the probe position P (x ₁ , y ₁ , z ₁ ), two points Q (x ₂ , y ₂ , z ₂ ) 404 and R located in the vicinity from the points on the surface of the housing. (x ₃ , y ₃ , z ₃ ) 405 is selected.
Since the vertical vector X403 on the housing surface at the probe position P (x ₁ , y ₁ , z ₁ ) is orthogonal to the vector PQ407 connecting the probe position P and the point Q and the vector PR406 connecting the probe position P and the point R, the inner product is Zero. therefore,
(Equation 1) X · PQ = 0
(Equation 2) X · PR = 0 holds.
Further, the case surface vertical vector X (x ₄ , y ₄ , z ₄ ) is a unit vector, and the mean square of (x ₄ , y ₄ , z ₄ ) coordinates is 1.
(Formula 3) x ₄ ^ 2 + y ₄ ^ 2 + z ₄ ^ 2 = 1 holds.
The equations (1), ( ₂ ), and (3) are solved to obtain a housing surface vertical vector X (x ₄ , y ₄ , z ₄ ).

In step S102, an angle θ207 formed by the measurement coil cross-section vector 205 of the magnetic field in the current probe and the housing surface vertical vector 203 is calculated.
First, the probe inclination angle (θ _x , θ _y , θ _z ) output from the position / orientation sensor 206 of the surface current measurement probe 200 is a unit vector C (x ₅ , y ₅ , z ₅ ) of the measurement coil cross section of the probe. )
(Equation 4) C (x ₅ , y ₅ , z ₅ ) = tan (Angle (θ _x , θ _y , θ _z ))
The angle θ formed by the unit vector C (x ₅ , y ₅ , z ₅ ) of the probe measurement coil cross section and the housing surface vertical vector X (x ₄ , y ₄ , z ₄ ) is
(Expression 5) Calculated from cos θ = C · X. (・ Represents inner product.)
In step S103, correction calculation of the magnetic field measurement data 209 measured by the surface current measurement probe 200 is performed.
The magnetic field measurement data Bm (f) of the magnetic flux density becomes maximum when the measurement probe is vertically contacted with the surface of the casing.
(Expression 6) Bm (f) = B (f) cosθ
From Equation 6, the magnetic flux density B (f) is calculated. f is a frequency, and the magnetic flux density is calculated for each frequency.

In step S104, the surface current is calculated from the magnetic flux density calculated in S103.
The surface current vector I (f) is given by the following equation according to Bio-Savart's law.
(Expression 7) I (f) = B (f) * 2πa / μ ₀
Here, a represents the distance between the surface current and the probe, and the distance t between the housing surface and the probe and the individual variation coefficient Kp of the probe,
(Equation 8) Calculate by a = Kp * t.
Here, μ ₀ is the Coulomb magnetic constant.

Returning to the description of the failure diagnosis system 100 in FIG. 1, the output of the surface current vector calculation unit 102 of the surface current vector measurement system 101 is the probe position P (x ₁ , y _{1) obtained} by mapping the probe position coordinates P ₀ onto the housing surface. , z ₁ ) and the surface current vector I (f) are output by the number of measurement points. That is, surface current vector distribution data 110 is output.

FIG. 6 is a flowchart for explaining failure diagnosis processing of the failure diagnosis system 100 according to the present embodiment.

In the present embodiment, the surface current measurement probe 200 is scanned manually or by mechanical means along the surface of the casing of the diagnosis target device or the surface of the control board in the diagnosis target device, for example, probe position information. Each time 210 changes by a predetermined scanning distance, the surface current is measured, and the surface current vector calculation unit 102 calculates and outputs the surface current vector.

In step S201, the failure diagnosis system 100 measures the surface current by scanning the surface of the casing of the diagnosis target device or the surface of the control board in the diagnosis target device at the first timing by the surface current vector measurement system 101 to be mounted. In step S 202, the measured surface current vector distribution data 110 is stored in the memory 103.

The “first timing” at which the surface current vector measurement system 101 measures the distribution of the surface current is a timing measured when it is confirmed that the diagnosis target device is operating normally prior to the failure diagnosis process. . The distribution data 110 of the surface current vector measured here is stored in the memory 103, and the stored data in the memory 103 is always read and used in subsequent failure diagnosis processing. If it is determined that there is no change in the surface current vector during normal operation, such as when the specification of the diagnosis target device is changed, the data stored in the memory is not updated. Normally, the processing up to storing the surface current vector distribution data in the memory in S202 is implemented as a program for registering surface current vector distribution data during normal operation, and the subsequent failure diagnosis processing is implemented as a separate program. However, in the flowchart of FIG. 6, the steps of both programs are described in succession.

Returning to the flowchart of FIG. 6, next, in step S <b> 203, the surface current vector measurement system 101 scans the surface of the casing of the diagnostic target device or the surface of the control board in the diagnostic target device at the second timing to scan the surface current. Measure. In step S204, the surface current vector distribution data 110 stored in the memory 103 is compared with the surface current vector distribution data 110 measured at the second timing.
The “second timing” means that when a failure diagnosis process of the diagnosis target device is started and a predetermined diagnosis cycle time provided in the failure diagnosis system 100 is reached, or an instruction to start diagnosis is input to the failure diagnosis system 100 It is the time.

The comparison process of the distribution data of the surface current vector in step S204 is executed by the peak value comparison unit 104, the frequency characteristic comparison unit 105, and the surface current vector angle comparison unit 106 of the failure diagnosis apparatus 120.

The surface current vector distribution data 110 cannot always accurately compare surface current vectors at the same position depending on the scanning method of the probe and the difference in the position where the data is captured. However, in the measurement of the surface current at the first and second timings, the probe scanning method and the data capturing position are operated as close as possible. In the comparison process of the distribution data 110 of the surface current vectors, the surface current vectors I (f) whose probe positions P (x ₁ , y ₁ , z ₁ ) are within the allowable error range are compared.

The peak value comparison unit 104 extracts the difference in current intensity of the surface current vector I (f) at the same frequency f. One or more frequencies f to be compared are set in advance.

In the frequency characteristic comparison unit 105, for example, when the difference in current intensity at a specific frequency f in the frequency spectrum of both surface current vectors I (f) to be compared is equal to or greater than an allowable error, the frequency characteristics do not match. Is determined. In the main frequency f (a frequency is designated in advance) in the frequency spectrum of the surface current vector I (f), a match / mismatch is similarly determined. The frequency characteristic comparison unit 105 executes the processing for comparing the above frequency characteristics. If the number of mismatches occurs at one or more locations, for example, the frequency spectra of both surface current vectors I (f) to be compared are determined to be mismatched.

The surface current vector angle comparison unit 106 extracts a difference between angles of both surface current vectors I (f) to be compared.

In step S205, it is determined whether or not the difference in surface current is within a predetermined threshold. That is, in the surface current vector distribution data 110 to be compared, step S204 is performed for all combinations of surface current vectors I (f) whose probe positions P (x ₁ , y ₁ , z ₁ ) are within an allowable error range. Then, the result of the comparison process is input to determine whether it is normal.

In the fault diagnosis unit 107, the output of the difference between the surface currents in the peak value comparison unit 104, the frequency characteristic comparison unit 105, and the surface current vector angle comparison unit 106 is compared with a preset threshold value. For example, the difference in current intensity of the surface current vector I (f) at the set frequency f is set to the first threshold value (a plurality of threshold values may be set for each frequency f) and the difference in frequency characteristics. Is compared with the second threshold value and the angle difference between the surface current vector I (f) and the third threshold value. judge. The comparison between the output of each of these comparison units and the threshold value may be determined by only the output of one of the comparison units, if necessary, or any combination or output of all the comparison units. It may be determined by comparing with a threshold value. If it is determined that any one or a combination of preset threshold values exceeds the threshold value, the surface current vector I (f) is determined to be abnormal. These determinations are made for all combinations of surface current vectors I (f). For example, if abnormality is determined in one or more surface current vectors I (f), the process proceeds to step S206. If all surface current vectors I (f) are determined to be normal, step S208 is performed. Migrate to

In step S206, the probe position P (x ₁ , y ₁ , z ₁ ) of the surface current vector I (f) determined to be abnormal is used as the surface current vector I (f) at the same frequency f that is, for example, a crest value comparison. Are arranged in descending order of current intensity difference. The difference value to be compared may be a difference in frequency characteristics or an angle difference between both surface current vectors I (f).

In step S207, the probe position P (x ₁ , y ₁ , z ₁ ) of the surface current vector I (f) having the maximum surface current difference compared in step S206 is determined as the failure location, An internal module or the like closest to the position is specified and displayed on the monitor 108.
In step S208, at the second timing, no abnormality is found in the surface current measured by scanning the surface of the casing of the diagnosis target device or the surface of the control board in the diagnosis target device, and the result determined to be normal is monitored. The failure diagnosis process is terminated.

5A and 5B, the surface current vector measurement system 101 of the present embodiment scans the surface of the cylindrical casing of the diagnostic target device, and the distribution data 110 of the surface current vector I (f) is obtained. An example is shown in which the distribution data 110 of the surface current vector I (f) as a measurement result is displayed on the monitor 108 by the fault diagnosis system 100 after measurement. Here, a measurement result at the second timing, for example, 3 result of scanning lines, the probe position P on the scanning path _{_{(x 1, y 1, z}} 1) by the surface current vector I (f ) Is displayed. 5A is an example in which a cylindrical housing surface 502 is displayed in a three-dimensional manner, and FIG. 5B is an example of a housing surface 503 in a two-dimensional development view.
The surface current vector I (f) 501 determined to be an abnormal surface current vector as a result of the failure diagnosis process in the failure diagnosis system 100 is displayed thickly or by changing its color. Further, in FIG. 5B, the fault location 504 causing the abnormal current is identified and displayed upstream of the abnormal surface current vector 501. Further, when the internal modules 505-1 to 505-4 of the structure inside the housing are displayed in accordance with the development view 503, the failed module can be specified.

Thus, by evaluating the temporal change of the surface current vector I (f) acquired by the surface current vector measurement system, it is possible to diagnose a failure of the diagnosis target device or the control board.
According to the present embodiment, even with a control board that does not have a fault diagnosis function, it is possible to perform fault diagnosis of the device or the control board without changing the control board, so that it can be realized at low cost and without stopping the apparatus. Since it can be installed, the impact on running costs is small.

FIG. 9 shows an embodiment in which this fault diagnosis system is applied to a scanning electron beam type semiconductor inspection / measurement apparatus. The scanning electron beam type semiconductor inspection / measurement apparatus includes an electron gun 901 that emits an electron beam, an acceleration electrode 912 that accelerates the electron beam, aperture electrodes 902-1 and 902-2 for reducing the electron beam diameter, Deflection electrodes 903-1 and 903-2 for adjusting the irradiation position of the electron beam, a stage 904 on which the sample 905 is set, a detector 906 for detecting secondary electrons emitted from the sample 905, and a detection signal are amplified. , A signal detection board 907 that performs signal processing by converting it into a digital signal, a monitor 908 that displays an image of the signal processed data, and control boards 911-1 and 911- for applying a control voltage or control current to each electrode. This is an electron microscope composed of 2,911-3 and 911-4. In this electron microscope, a fault diagnosis system composed of a surface current measuring probe 200 and a fault diagnosis device 120 includes a current that flows from the control board to the electrode, and a surface current that flows from the control board to the ground through the housing of the electron microscope. It is installed to scan the control board and the surface of the housing, measure the surface current, and perform fault diagnosis of the scanning electron beam semiconductor inspection / measurement device Yes.

FIG. 10 is a diagram showing a form in which the failure diagnosis system of the present embodiment is applied to an automobile. A plurality of

control units

1004 and 1005 for controlling an engine, a brake system, a navigation system, and the like are mounted in the automobile, and an inverter 1002 and a power supply unit 1003 for controlling the motor 1001 are mounted.
By scanning the fault diagnosis system including the surface current measurement probe 200 and the fault diagnosis device 120 along the vehicle body surface so that the surface current flowing from the

control units

1004 and 1005 and the inverter 1002 to the vehicle body surface can be detected. It becomes possible to detect a failure of the circuit and improve safety.

FIG. 7 shows an example of the configuration of a surface current measurement probe 700 having a position / attitude detection function used in the surface current vector measurement system 101 according to the second embodiment of the present invention. This probe includes a current-in-probe coil 701, an analog amplifier 711 that amplifies the output signal of the coil, and a position / posture sensor 706 that outputs probe position / posture information 710. The coil 701 includes, for example, a flux gate sensor, a loop coil, a Hall element, and other sensors that can detect a magnetic field according to the minimum frequency of measurement. Further, an A / D converter for converting the output signal of the amplifier 711 into a digital signal and a digital signal processing means 708 are provided.
The surface current measurement probe 700 outputs magnetic field measurement data 709 converted into a digital signal by an A / D converter and digital signal processing means 708, and probe position / posture information 710.

The surface current vector calculation unit 102 receives the output of the surface current measurement probe 700, and uses the position information (CAD data or the like) of the housing surface 702 of the diagnosis target device that is separately prepared, and uses the housing surface vertical vector 703. And a distance 704 between the housing surface 702 and the surface current measurement probe 700 is calculated, and further, a cross-sectional vector 705 of the magnetic field measurement coil 701 in the current probe is used to calculate the magnetic field measurement coil cross section in the current probe. An angle θ707 formed by the vector 705 and the casing surface vertical vector 703 is calculated. Further, the magnetic field measurement data 709 which is the output of the surface current measurement probe 700 is calibrated and calculated using the curvature θ ′ 712 of the housing surface.

FIG. 8 illustrates the processing of the surface current vector calculation unit 102 of the surface current vector measurement system 101.

In step S301, similarly to step S101, and calculates the casing surface vertical vector 703 of the probe position output from the position and orientation sensor 706 coordinate P _{0 (previously} determined representative points P _R representing the position of the probe.) .

In step S302, as in step S102, the angle θ707 formed by the measurement coil cross-section vector 705 of the magnetic field in the current probe and the casing surface vertical vector 703 is calculated.

In step S303, similarly to step S103, correction calculation of the magnetic field measurement data 709 measured by the surface current measurement probe 700 is performed.

In step S304, the surface current is calculated from the magnetic flux density B (f) calculated in S303.
The surface current vector I (f) is given by the following equation according to Bio-Savart's law.
(Expression 7) I (f) = B (f) * 2πa / μ ₀
Here, a represents the distance between the surface current and the probe, μ ₀ represents the magnetic constant of Coulomb, the distance t between the housing surface and the probe, the individual variation coefficient Kp of the probe, and the curvature θ ′ of the housing surface. By
(Equation 9) a = Kp * t * cos θ ′

Measurement of the surface current vector based on this flowchart makes it possible to measure the surface current vector on the surface of the housing with unevenness with high sensitivity.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

DESCRIPTION OF SYMBOLS 100 Fault diagnosis system 101 Surface current vector measurement system 102 Surface current vector calculation part 103 Memory 104 Peak value comparison part 105 Frequency characteristic comparison part 106 Surface current vector angle comparison part 107 Fault diagnosis part 108 Monitor 109 External interface 110 Surface current vector distribution Data 111 Cable 120 Failure diagnosis device 200 Surface current measurement probe 201 Coil in current probe (example: FG sensor, Hall element)
202 Case surface (partially displayed)
203 Case vertical vector 204 Distance between case surface and probe 205 Magnetic field measurement coil cross section vector 206 in current probe Position / attitude sensor 207 Magnetic field measurement coil cross section vector in current probe and case surface vertical vector The angle θ
208 A / D conversion, digital signal processing means 209 Magnetic field measurement data 210 Probe position / posture information 211 Amplifier 401 Probe position P (x ₁ , y ₁ , z ₁ )
402 Case surface (partially displayed)
403 Case surface vertical vector X
Point Q on the surface near 404 P
Point R on the surface near 405 P
406 Vector PR
407 Vector PQ
501 Abnormal surface current vector 502 Case surface (example of cylindrical shape)
503 Case surface (example of development)
504 Fault location display 505-1 to 505-4 Internal module 700 Surface current measurement probe 701 according to the second embodiment Coil in current probe (example: FG sensor, Hall element)
702 Housing surface (partially displayed)
703 Case surface vertical vector 704 Distance between case surface and probe 705 Magnetic coil measurement coil cross section vector 706 Position / attitude sensor 707 Current probe magnetic field measurement coil cross section vector and housing surface vertical vector The angle θ
708 A / D conversion, digital signal processing means 709 Magnetic field measurement data 710 Probe position and orientation information 711 Amplifier 712 Curvature θ ′ of housing surface
901 ... Electron guns 902-1, 902-2 ... Diaphragm electrodes 903-1, 903-2 ... Deflection electrodes 904 ... Stage 905 ... Sample 906 ... Detector 907 ... Signal detection board 908 ... Monitors 911-1, 911-2 911-3, 911-4 ... Control board 1001 Motor 1002 Inverter 1003

Power supply unit

1004, 1005 Control unit

Claims

A system for measuring a magnetic field generated based on a surface current flowing through a measurement object,
A surface current measuring probe comprising a coil for measuring the magnetic flux density of the magnetic field, a position / posture sensor for detecting the position and posture of the probe, and an amplifier for amplifying the output signal of the coil;
From the probe position and orientation information, the angle θ formed by the measurement coil cross-section vector and the measurement target housing surface vertical vector is calculated, the magnetic flux density is corrected by the angle θ, and the surface current is calculated from the corrected magnetic flux density. A surface current vector measuring system comprising a surface current vector calculating unit for calculating a vector.
The surface current vector calculation unit calculates a case surface vertical vector from the position information of the probe and the case surface information of the measurement target, and calculates a measurement coil cross-section vector and a measurement target case from the posture information of the probe. An angle θ formed with a surface vertical vector is calculated, magnetic field measurement data measured by a probe is corrected by the angle θ to calculate a magnetic flux density, and a surface current vector is calculated from the corrected magnetic flux density. Item 4. The surface current vector measurement system according to Item 1.
The surface current vector calculation unit calculates the surface current vector by correcting the corrected magnetic flux density by a distance between the measurement target casing surface and the probe and a curvature of the casing surface. Item 3. The surface current vector measurement system according to Item 2.
The coil for measuring the magnetic flux density of the magnetic field of the surface current measurement probe is appropriately selected from a fluxgate sensor, a loop coil, or a Hall element according to the minimum frequency of measurement. 2. The surface current vector measurement system according to 1.
A surface current vector measurement system for measuring the magnetic field intensity generated by the current flowing from the control board of the diagnostic target device;
A memory that stores distribution data of a surface current vector during normal operation of the diagnostic target device acquired by the surface current vector measurement system;
A comparison unit that compares the storage data of the memory and the distribution data of the surface current vector acquired by the surface current vector measurement system;
A failure diagnosis system comprising: a failure diagnosis unit that determines that the diagnosis target device has failed when difference data in units of surface current vectors compared by the comparison unit exceeds a predetermined threshold value.
In the memory, a distribution of surface current vectors measured on a scanning path obtained by scanning the surface current measuring probe of the surface current vector measuring system along the housing of the diagnostic target device or the control board during normal operation. 6. The failure diagnosis system according to claim 5, wherein data is recorded.
The comparison unit extracts a difference in current intensity of the surface current vector I (f) at the same frequency f;
A second comparison unit for determining whether the current intensity difference at a specific frequency f in the frequency spectrum of both surface current vectors I (f) to be compared matches or does not match;
The failure diagnosis system according to claim 5, further comprising a third comparison unit that extracts a difference between angles of both surface current vectors I (f) to be compared.
The failure diagnosis unit includes first to third threshold values corresponding to the outputs of the first to third comparison units, and any one of the comparison units as necessary. One or any combination of the outputs of the comparators is compared with the corresponding threshold value, and if all are within the threshold value, the normal surface current vector I (f) is determined. The failure diagnosis system according to claim 7.
In addition, a monitor is connected via an external interface,
The fault diagnosis unit includes a surface current vector distribution data measured by the surface current vector measurement system at the time of diagnosis on the surface of the case of the diagnosis target device displayed in a three-dimensional manner, and in the diagnosis target device displayed in a two-dimensional development view. 6. The fault diagnosis system according to claim 5, wherein a surface current vector I (f) is displayed on a monitor at a probe position P on the scanning path.
The fault diagnosis unit displays the surface current vector I (f) at the probe position P on the scanning path on the surface of the casing of the diagnosis target device displayed in a three-dimensional display and a two-dimensional development view on the monitor. Based on the diagnosis result of each surface current vector, the vector determined to be an abnormal surface current vector is displayed so that it can be distinguished from the normal vector, and the fault location determined to be the cause of the abnormal current The fault diagnosis system according to claim 9, wherein the fault diagnosis system is specified and displayed.
An electron gun that emits an electron beam;
An accelerating electrode that accelerates the electron beam;
A diaphragm electrode for narrowing the electron beam diameter;
A deflection electrode for adjusting the irradiation position of the electron beam;
A stage to place the sample,
A detector for detecting secondary electrons emitted from the sample;
A signal detection board that amplifies the detection signal, converts it into a digital signal, and performs signal processing;
A control board for applying a control voltage or a control current to each electrode;
A surface current measurement probe that is scanned in the vicinity of the control board or a current path flowing from the control board;
A surface current vector measurement system that calculates the distribution of the surface current vector from the magnetic field strength signal detected by the surface current measurement probe and the position and orientation information of the probe;
A scanning electron microscope comprising: a failure diagnosis system that determines a failure of the control board from the distribution data of the surface current vector.