JP2016038200A - Checkup device, checkup method, checkup program, and capacity measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a checkup device, a checkup method and a checkup program that can automate checkup of plate-shaped products in a simple system configuration, and a capacity measuring device to be built into such a checkup device.SOLUTION: A checkup device is equipped with a flat first electrode, a second electrode so positioned as to sandwich a plate-shaped measurement object arranged along the first electrode between itself and the first electrode and smaller in size than the first electrode, a shifter that shifts the second electrode along the surface of the measurement object, a measuring circuit that measures the capacity occurring between the first electrode and the second electrode in each position along the surface of the measurement object, and a determining unit that determines any faulty part in the measurement object on the basis of the capacity in each position measured by the measuring circuit.SELECTED DRAWING: Figure 4

Description

The present invention relates to an inspection apparatus, an inspection method, an inspection program, and a capacity measurement apparatus.

Conventionally, ceramic substrates are used in power electronics and other fields. The ceramic substrate is becoming thinner due to demands for downsizing of the apparatus, and as a result, it is indispensable to inspect after generation of the substrate for cracks.
At present, there is no low-cost detection device, and the mainstream inspection method is to inspect the entire ceramic substrate with a stereomicroscope by labor-intensive visual inspection.
For such a current situation, for example, Patent Document 1 discloses an inspection apparatus using image processing.

JP 2011-220738 A

  However, in any method such as image inspection, ultrasonic inspection, X-ray inspection, etc., there is currently no inspection method suitable for human sea tactical visual inspection in terms of cost performance.

  For example, in the case of inspection by image processing, since the crack size of the ceramic substrate to be detected is a very fine size of several microns width, the recognition of the crack by the image can be recognized only after being expanded several tens of times. This is thought to be a cause of cost increase. That is, since it is necessary to collect a large number of images for inspecting the entire substrate and inspect each image for cracks, it takes time. As a system, human cost performance will be overwhelmingly superior.

  On the other hand, labor-intensive visual inspection by humans cannot avoid the possibility of fatigue or lack of concentration due to work, and requires careful operation to prevent missing defects.

  The same situation exists not only for ceramic substrates but also for plate-like products that can cause fine defects.

  In view of the above circumstances, an object of the present invention is to provide an inspection device, an inspection method, an inspection program, and a capacity measuring device incorporated in such an inspection device that can automate the inspection of a plate-like product with a simple system configuration. And

  An inspection apparatus according to the present invention that achieves the above object is provided by sandwiching a flat plate-like first electrode and a plate-like measurement object disposed along the first electrode between the first electrode and the first electrode. A second electrode smaller than one electrode, a mover for moving the second electrode along the surface of the measurement object, and the first electrode and the second electrode for each position along the surface of the measurement object And a determination circuit for determining a defective portion of the measurement object based on the capacitance at each position measured by the measurement circuit.

  According to such an inspection apparatus of the present invention, inspection of a plate-like measurement object can be automated using capacitance measurement that can be realized with a simple circuit. In addition, since the inspection apparatus of the present invention uses capacity measurement, it can detect even a defective portion hidden inside the measurement object.

  In such an inspection apparatus, it is preferable that the second electrode includes a plurality of second electrodes that do not overlap in the moving direction. With such a plurality of second electrodes, it is possible to perform measurement at a plurality of locations at a time, thereby shortening the measurement time.

  Moreover, the said measurement circuit is the charging / discharging circuit which charges / discharges in multiple times between the said 1st electrode and the said 2nd electrode in each position along the surface of the said measuring object, The said produced by the said charging / discharging circuit An integration circuit that integrates a charge / discharge waveform between the first electrode and the second electrode, and a voltage measurement circuit that measures a voltage value of the charge / discharge waveform integrated by the integration circuit are provided. It is also suitable.

  Such a suitable inspection apparatus can obtain the same result as the averaging of a plurality of measurements by integrating the charge / discharge waveform, and the accuracy of the measurement value is improved.

  In this preferable inspection apparatus, it is further preferable that the integration circuit is a CR integration circuit. The circuit is simplified by using the CR integration circuit.

  It is also preferable that the voltage measurement circuit is a differential amplifier using a voltage value of an integrated charge / discharge waveform in a normal measurement object as a reference voltage. A minute voltage value change caused by a minute capacitance change due to a minute defect can be easily measured by a differential amplifier.

  In addition, the inspection method of the present invention that achieves the above-mentioned object is located between a first electrode and a plate-like measurement object arranged along the first electrode, which is arranged along the plate-like first electrode. A measurement process for measuring a capacitance generated between the first electrode and the second electrode at each position along the surface of the measurement object, and a moving process of moving the small second electrode along the surface of the measurement object And a determination process for determining a defective portion of the measurement object based on the capacity at each position measured in the measurement process.

  The inspection program of the present invention that achieves the above-mentioned object is located on a computer with a plate-like measurement object arranged along a plate-like first electrode sandwiched between the first electrode and the first electrode. A moving process of moving a second electrode smaller than the electrode along the surface of the measurement object, and a capacitance generated between the first electrode and the second electrode for each position along the surface of the measurement object. A measurement process for measurement and a determination process for determining a defective portion of the measurement object based on the capacity at each position measured in the measurement process are performed.

  Furthermore, the capacity measuring device of the present invention that achieves the above object is provided by sandwiching a plate-shaped first electrode and a plate-shaped measuring object disposed along the first electrode between the first electrode and the first electrode. A second electrode smaller than the first electrode, a mover that moves the second electrode along the surface of the measurement object, and the first electrode and the position for each position along the surface of the measurement object A measurement circuit that measures a capacitance generated between the first electrode and the second electrode, and the measurement circuit performs a plurality of times between the first electrode and the second electrode at each position along the surface of the measurement target. A charge / discharge circuit for charging / discharging, an integration circuit for integrating a charge / discharge waveform between the first electrode and the second electrode generated by the charge / discharge circuit, and a charge / discharge waveform integrated by the integration circuit A voltage measuring circuit for measuring the voltage value of And wherein the door.

  According to the present invention, inspection of plate products can be automated with a simple system configuration.

It is a figure which shows roughly the structure of the crack which arose in the ceramic substrate. It is a figure which shows the detection principle of a crack. It is a figure which shows the structure of an inspection apparatus generally. It is a figure which shows the structure of a measuring rod. It is a figure which shows a charging / discharging waveform. It is a figure which shows notionally the hardware constitutions of a measurement control apparatus. It is a block block diagram which shows the function structure of a measurement control apparatus. It is a flowchart showing operation | movement of a measurement control apparatus.

Specific embodiments of the present invention will be described below with reference to the drawings.
First, the structure of a crack that is a typical detection target in the inspection apparatus will be described.

  FIG. 1 is a diagram schematically showing the structure of cracks generated in a ceramic substrate.

  FIG. 1 shows a state in which a 1 mm square region is cut out of a ceramic substrate 1 having a thickness of 0.65 mm as an example.

  The crack 2 is exposed on the surface of the ceramic substrate 1 with a width of about 1 μm, and the crack 2 continues deeply inside the ceramic substrate 1, but does not necessarily penetrate the front and back surfaces of the ceramic substrate 1. There are cases where the crack 2 is exposed only on one side of the front and back of the ceramic substrate 1, and there are rare cases where the crack 2 is hidden inside the ceramic substrate 1 like a cavity. The crack 2 hidden inside the ceramic substrate 1 cannot be found by conventional visual inspection or inspection by image processing.

  The crack 2 of the ceramic substrate 1 shown here is a typical example of a detection target in the detection device of the present invention. In the detection device of the present invention, a plate-like measurement object other than the ceramic substrate (for example, a resin substrate) It is also possible to deal with defects other than cracks (for example, burial of foreign matter). However, below, for convenience of explanation, the description will be continued with a crack of the ceramic substrate as a typical example as a detection target. Such a crack of the ceramic substrate is a typical detection target, but is not an easy detection target. Rather, it is a detection target that requires detection with the highest degree of difficulty among defects that can be handled by the present invention.

  Next, the principle of detecting such a detection target will be described.

  FIG. 2 is a diagram illustrating the principle of detection of cracks.

  In the present invention, the capacitance generated between the flat plate-like back electrode 10 and the rod-shaped measurement electrode 20 is measured by the measurement circuit 30 in order to detect the detection target described above. The back electrode 10 corresponds to an example of the first electrode referred to in the present invention. The measurement electrode 20 corresponds to an example of the second electrode according to the present invention, and the measurement circuit 30 corresponds to an example of the measurement circuit according to the present invention.

  The back electrode 10 extends over the entire back surface of the ceramic substrate 1, and the measurement electrode 20 is in contact with the surface of the ceramic substrate 1 at a 1 mm square tip. The measurement electrode 20 does not need to be in contact with the surface of the ceramic substrate 1 for the purpose of measuring the capacitance, and the measurement electrode 20 is away from the surface of the ceramic substrate 1 and is kept at a certain distance from the back electrode 10. You may be in the state.

  When the measurement electrode 20 is moved along the surface of the ceramic substrate 1, the capacitance is lowered because the ceramic material that is a dielectric is less in the portion where the crack 2 is generated than in other portions. When the amount of reduction is estimated, since the crack 2 has a width of about 1 micron as described above with respect to the measuring electrode 20 of 1 mm square, the capacitance changes about 1/1000. This change of about 1/1000 is the order of Atofarad as an order of measurement, and a defective portion of the ceramic substrate 1 is detected by detecting such a change in capacitance. In addition, in the case of defects other than cracks, such as burial of foreign matter, the size of the foreign matter is often in the order of sub millimeters, and the capacity change in that case is expected to be larger than the capacity change due to cracks. It is easier to detect than a crack. In addition, even if cracks are not exposed on the surface of the substrate, the capacitance changes. Therefore, according to the inspection method of the present invention using capacitance measurement, it can be detected by conventional visual inspection or inspection by image processing. It is possible to detect a defect that has not occurred. This means that if there is an inhomogeneous part that changes the electrostatic capacitance in a part of the plate-like inspection object that should be homogeneous (desirably homogeneous), it is detected as a defective part.

  Next, an embodiment of a specific inspection apparatus using such a detection principle will be described.

  FIG. 3 is a diagram schematically showing the configuration of the inspection apparatus.

  FIG. 3 shows an inspection apparatus 100 that is an embodiment of the present invention.

  The inspection apparatus 100 includes a measuring unit 110 provided with a large number of measuring rods 40 (3 × 6 = 18 as an example here) incorporating the measuring electrode 20 and the measuring circuit 30 shown in FIG. A back electrode 10 on which the target ceramic substrate 1 is placed is also provided.

  Further, in this inspection apparatus 100, a driving mechanism 120 that moves the measuring unit 110 in the scanning direction indicated by an arrow in the drawing by driving the measuring unit 110 along the guide rail 50 with a stepping motor (not shown). Is provided. As the measurement unit 110 is driven by the drive mechanism 120 in this way, each measurement electrode 20 provided in the measurement unit 110 moves in the scanning direction along the surface of the ceramic substrate 1. The drive mechanism 120 corresponds to an example of a moving device according to the present invention.

  A large number of measurement bars 40 (and each measurement electrode 20) arranged in the measurement unit 110 are not arranged in the scanning direction but move on different scanning lines whose positions are shifted from each other. Of the measuring rods 40 arranged as 3 × 6 shown as an example in FIG. 3, six measuring rods 40 arranged in a row are arranged at intervals shown in the drawing in a direction orthogonal to the scanning direction. . Further, the three measuring bars 40 arranged in a row are arranged in a direction slightly inclined with respect to the scanning direction. When viewed from the scanning direction, they are shifted from each other by about the width of the measuring electrode 20 (ie, about 1 mm). Yes. With the 3 × 6 = 18 measuring rods 40 arranged in this way, the entire width of 18 mm is scanned and inspected all at once. Thus, by providing a plurality of measurement electrodes that move on different scanning lines (that is, do not overlap with each other in the moving direction), the efficiency of inspection is improved.

  The inspection apparatus 100 shown in FIG. 3 is also provided with a measurement control device 130 that is connected to each measurement rod 40 and the drive mechanism 120 of the measurement unit 110 and controls measurement by the measurement unit 110 and drive by the drive mechanism 120. The measurement control device 130 is a device having a function as an example of a determination device according to the present invention. And the part except this measurement control apparatus 130 among the inspection apparatuses 100 shown in FIG. 3 is equivalent to one Embodiment of the capacity | capacitance measuring apparatus of this invention.

  Next, details of the measurement circuit 30 incorporated in each measurement rod 40 will be described.

  FIG. 4 is a view showing the structure of the measuring rod 40.

  As described above, the measurement circuit 30 and the measurement electrode 20 are incorporated in each measurement rod 40. Although not shown in FIG. 3, the measurement unit 110 includes an oscillator 60 that generates a rectangular wave having a constant period. It has been. One oscillator 60 is shared by many measuring bars 40.

  The measurement circuit 30 includes a charge / discharge circuit 31 that connects the measurement electrode 20 and the oscillator 60. The charging / discharging circuit 31 repeats periodic application and release of a voltage to the measurement electrode 20 by the action of the rectangular wave generated from the oscillator 60 and the diode switch. Charging and discharging are repeated for the capacity generated between them. The charge / discharge circuit 31 shown in FIG. 4 corresponds to an example of the charge / discharge circuit according to the present invention.

  FIG. 5 is a diagram illustrating a charge / discharge waveform.

  The horizontal axis in FIG. 5 represents time, and the vertical axis represents the potential of the measurement electrode 20.

  The charging / discharging waveform 70 as shown in FIG. 5 is generated by the repeated charging and discharging by the charging / discharging circuit 31. The charging period and the discharging period are repeated in the same period as the period of the rectangular wave from the oscillator 60, the potential rises in the charging period, and instantaneously becomes zero with the start of the discharging period. Since the period of the rectangular wave generated by the oscillator 60 is sufficiently short, the potential increase during the charging period shows a linear increase. The angle of the potential rise depends on the size of the capacitance generated between the back electrode 10 and the measurement electrode 20, and therefore the potential rise angle changes when the capacitance changes, and the potential immediately before the discharge (that is, charge / discharge) The wave height of the waveform 70 also changes.

  Such repetition of charging and discharging in the charging / discharging waveform 70 is equivalent to repeating many measurements, and therefore, charging and discharging are repeated as many times as possible (that is, the period of the rectangular wave generated by the oscillator 60). Is as short as possible).

  Returning to FIG. 4, the description will be continued.

  The measurement circuit 30 includes a CR integration circuit 32 connected to the measurement electrode 20, and the charge / discharge waveform described above is integrated by the CR integration circuit 32. As a result, the CR integration circuit 32 outputs a constant voltage value representing the magnitude of the capacitance generated between the back electrode 10 and the measurement electrode 20. The CR integration circuit 32 corresponds to a preferred example of the integration circuit referred to in the present invention. As shown in FIG. 4, when the CR integration circuit 32 is provided as an integration circuit, the circuit structure is simplified and can be easily incorporated into a small structure such as the measuring rod 40.

  Furthermore, the measurement circuit 30 is provided with a differential amplifier 33 connected to the output side of the CR integration circuit 32.

  The differential amplifier 33 is supplied with a voltage value output from the CR integration circuit 32 on a normal ceramic substrate 1 without cracks 2 as a reference voltage. This reference voltage may be applied to the differential amplifier 33 from some storage means, or obtained from the measurement rod 40 located at the end of the many measurement rods 40 provided in the measurement unit 110. A voltage value may be given. The differential amplifier 33 corresponds to a preferred example of the voltage measuring circuit referred to in the present invention.

  The differential amplifier 33 has a function of measuring an integrated voltage value output from the CR integration circuit 32 (that is, a voltage value reflecting a capacitance generated between the back electrode 10 and the measurement electrode 20). Since the difference from the reference voltage is amplified at the time of measurement, a voltage change representing a minute capacity change caused by the crack 2 is enlarged and measured. As a result, the measurement of the order of atfarad as described above is realized.

  As described above, in the present invention, cracks are detected based on the detection principle using capacitance measurement, and therefore, an inspection can be realized by a simple measurement circuit as shown as an example in FIG. In addition, since the measurement circuit is simple as described above, it is possible to simultaneously perform measurement at a large number of locations with the configuration as shown in FIG. 3 to improve the inspection efficiency.

  The output of the differential amplifier 33 is the output of the measurement circuit 30, and the voltage value of this output is the measurement value at each measurement rod 40. This measurement value is taken in for each measurement position by the measurement control device 130 shown in FIG.

  Details of the measurement control device 130 will be described below.

  FIG. 6 is a diagram conceptually illustrating the hardware configuration of the measurement control apparatus.

  The measurement control device 130 uses a so-called personal computer as hardware, and includes a CPU 81, a RAM 82, a ROM 83, an HDD 84, an input / output (I / O) interface 85, an input device 86, and a display device 87. These elements are interconnected via a bus 88.

  The HDD 84 stores an embodiment of the measurement control program of the present invention that causes a personal computer to operate as the measurement control device 130. The measurement control program is read by the CPU 81 and executed.

  The RAM 82 is a memory used for a work area of the measurement control program and the like, and the measurement values taken from each measurement rod 40 are also temporarily stored. This measured value is finally stored in the HDD 84 as a data file.

  The I / O interface 85 exchanges control signals and measurement values with each measuring rod 40 and the drive mechanism 120.

  The input device 86 is specifically a mouse or a keyboard, and is operated when the inspection apparatus 100 instructs the start, end, setting, etc. of the inspection.

  The display device 87 is specifically a display or a printer, and displays the progress of the examination and presents it to the user.

  FIG. 7 is a block configuration diagram illustrating a functional configuration of the measurement control apparatus.

  When viewed as a functional configuration, the measurement control apparatus 130 includes a drive control unit 91, a measurement value acquisition unit 92, a crack determination unit 93, and a result output unit 94. These functions are functions constructed on the personal computer by executing the above-described measurement control program, and the functional configuration shown in FIG. 7 is also considered as the configuration of the measurement control program.

  The drive control unit 91 controls movement of the measurement unit 110 in the scanning direction by sending a control signal to the drive mechanism 120 shown in FIG. By controlling the drive mechanism 120 in this way, the drive control unit 91 recognizes the measurement position in the scanning direction, and information on the measurement position is sent to the result output unit 94.

  The measurement value acquisition unit 92 acquires a measurement value from each measurement rod 40, and controls the timing for taking in the measurement value from each measurement rod 40, thereby controlling the measurement timing of the voltage value by each measurement circuit 30. It is virtually controlled. Further, by recognizing from which measuring bar 40 the measurement value is taken in, the measurement position in the direction orthogonal to the scanning direction is recognized. Information on the recognized measurement position is also sent to the result output unit 94.

  The crack determination unit 93 determines whether or not each measurement value taken in by the measurement value acquisition unit 92 is a measurement value indicating the presence of a crack or the like. In the case of the present embodiment, the difference from the normal measurement value without cracks is taken in by the measurement value acquisition unit 92 by the differential amplifier 33 incorporated in each measurement rod 40. If the absolute value of the captured measurement value exceeds a predetermined threshold value, it is determined that some defect such as a crack or a foreign object has occurred. Such a determination is a simple determination and can be performed at high speed. The function of the crack determination unit 93 corresponds to a function as an example of a determination device according to the present invention.

  The result output unit 94 associates the determination result by the crack determination unit 93 with the information on the measurement position, displays the result on a display or the like, and records the data on the HDD as a data file.

  FIG. 8 is a flowchart showing the operation of the measurement control apparatus.

  When the control operation by the measurement control device 130 is started, first, in step S101, a control signal is sent from the drive control unit 91 to the drive mechanism 120 to control the movement of the measurement unit 110 in the scanning direction. As a specific control example, for example, after the measurement unit 110 is moved in the scanning direction by the width of the measurement electrode 20 (that is, 1 mm), the time required for measurement is stopped at that position, and then the measurement unit is further moved by 1 mm. Control that repeats the operation of moving 110 in the scanning direction is conceivable. The operation in step S101 corresponds to an example of the movement process referred to in the present invention.

  Next, in step S <b> 102, a measurement value is acquired by the measurement value acquisition unit 92. The measurement value acquisition timing by the measurement value acquisition unit 92 is, for example, the timing at which the measurement value is stationary at the measurement position by the drive control exemplified above. In the case of the present embodiment, such acquisition timing is synonymous with measurement timing, and thus step S102 corresponds to an example of a measurement process according to the present invention.

  Thus, based on the measurement value obtained in step S102, in step S103, the crack determination unit 93 determines whether the measurement value indicates the presence of a crack or the like as described above.

  In step S104, the result output unit 94 outputs the determination result in association with the position information, and then the control operation ends.

  Such a control operation efficiently and automatically inspects the ceramic substrate for cracks.

  In the above description, an inspection apparatus having a large number of measurement electrodes is illustrated as an embodiment. However, the detection apparatus and the capacitance measurement apparatus of the present invention may have only one measurement electrode (that is, the second electrode). good.

  Even in the case where a plurality of measurement electrodes are provided, in the detection device and the capacitance measurement device of the present invention, it is not essential that all the measurement electrodes move on different scanning lines. Are allowed to move on the same scanning line. Alternatively, for the purpose of increasing the number of times of measurement on one scanning line, all the measurement electrodes are allowed to move on the same scanning line.

DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2 Crack 10 Back electrode 20 Measuring electrode 30 Measuring circuit 31 Charging / discharging circuit 32 CR integration circuit 33 Differential amplifier 40 Measuring rod 60 Oscillator 100 Inspection apparatus 110 Measuring part 120 Drive mechanism 130 Measurement control apparatus 91 Drive control part 92 Measurement Value acquisition unit 93 Crack determination unit 94 Result output unit

Claims (8)

A flat first electrode;
A second electrode that is located between the first electrode and a plate-like measurement object disposed along the first electrode, and is smaller than the first electrode;
A mover for moving the second electrode along the surface of the measurement object;
A measurement circuit for measuring a capacitance generated between the first electrode and the second electrode for each position along the surface of the measurement object;
A determinator for determining a defective portion of the measurement object based on a capacity of each position measured by the measurement circuit;
An inspection apparatus comprising:   The inspection apparatus according to claim 1, further comprising a plurality of second electrodes that do not overlap in the moving direction as the second electrodes. The measurement circuit is
A charge / discharge circuit that performs charge / discharge a plurality of times between the first electrode and the second electrode at each position along the surface of the measurement object;
An integration circuit for integrating a charge / discharge waveform between the first electrode and the second electrode generated by the charge / discharge circuit;
A voltage measurement circuit for measuring a voltage value of a charge / discharge waveform integrated by the integration circuit;
The inspection apparatus according to claim 1, further comprising:   4. The inspection apparatus according to claim 3, wherein the integration circuit is a CR integration circuit.   The inspection apparatus according to claim 3, wherein the voltage measurement circuit is a differential amplifier that uses a voltage value of an integrated charge / discharge waveform in a normal measurement object as a reference voltage. A plate-like measurement object arranged along the flat plate-like first electrode is located between the first electrode and a second electrode smaller than the first electrode is moved along the surface of the measurement object. Moving process,
A measurement process for measuring a capacitance generated between the first electrode and the second electrode for each position along the surface of the measurement object;
A determination process for determining a defective portion of the measurement object based on the capacity of each position measured in the measurement process;
Inspection method characterized by passing through. On the computer,
A plate-like measurement object arranged along the flat plate-like first electrode is located between the first electrode and a second electrode smaller than the first electrode is moved along the surface of the measurement object. Moving process,
A measurement process for measuring a capacitance generated between the first electrode and the second electrode for each position along the surface of the measurement object;
A determination process for determining a defective portion of the measurement object based on the capacity of each position measured in the measurement process;
An inspection program characterized in that A flat first electrode;
A second electrode that is located between the first electrode and a plate-like measurement object disposed along the first electrode, and is smaller than the first electrode;
A mover for moving the second electrode along the surface of the measurement object;
A measurement circuit for measuring a capacitance generated between the first electrode and the second electrode for each position along the surface of the measurement object,
The measurement circuit is
A charge / discharge circuit that performs charge / discharge a plurality of times between the first electrode and the second electrode at each position along the surface of the measurement object;
An integration circuit for integrating a charge / discharge waveform between the first electrode and the second electrode generated by the charge / discharge circuit;
A voltage measurement circuit for measuring a voltage value of a charge / discharge waveform integrated by the integration circuit;
A capacity measuring device comprising:

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