Inspection equipment and inspection method

Abstract

This invention provides an inspection device and inspection method that are advantageous for accurately detecting abnormalities in capacitors. [Solution] The inspection device 13 includes a charging unit 51A that charges the capacitor W, a discharging unit 51B that discharges the capacitor W, a current measuring unit 52 that continuously measures the current of the capacitor W during discharge, and an abnormality detection unit 55 that detects abnormalities in the capacitor W based on a regression line relating to the discharge characteristics derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing within a judgment time range during discharge.

Description

Technical Field

[0001] The present disclosure relates to an inspection apparatus and an inspection method for detecting abnormalities in capacitors.

Background Art

[0002] Capacitors such as MLCCs (Multi-Layer Ceramic Capacitors) and electronic components equipped with capacitors are usually shipped after undergoing inspections for detecting defective products. In particular, in recent years, a large number of MLCCs have come to be used in devices such as automobiles and communication devices that require high levels of performance and safety, and it is desired to conduct inspections that guarantee the reliability of a large number of MLCCs at a higher level.

[0003] Regarding such inspections, for example, Patent Document 1 discloses a defect detection apparatus aimed at performing detection and screening of internal defects such as foreign matter contamination and pinholes in a multilayer ceramic capacitor in a short time. Further, Patent Document 2 discloses a pass / fail discrimination method aimed at discriminating the pass / fail of a capacitor in a short time.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a technique advantageous for accurately detecting abnormalities in capacitors.

Means for Solving the Problems

[0006] One aspect of the present disclosure relates to an inspection device comprising: a charging unit for charging a capacitor; a discharging unit for discharging a capacitor; a current measuring unit for continuously measuring the current of the capacitor during discharge; and an abnormality detection unit for detecting an abnormality in the capacitor based on a regression line relating to discharge characteristics derived from the logarithm of the measured current values ​​and the logarithm of the timing of the current measurement during a determination time range during discharge.

[0007] The current measurement unit continuously measures the current of the capacitor during charging, and the abnormality detection unit may detect an abnormality in the capacitor based on a regression line relating to the charging characteristics derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing within the judgment time range during charging.

[0008] The abnormality detection unit may detect an abnormality in the capacitor based on the degree of agreement between the logarithm of the measured current and the logarithm of the measurement timing with respect to the regression line.

[0009] The abnormality detection unit may detect an abnormality in the capacitor based on the logarithmic relationship of the measured current to at least one of the upper and lower limits of the current tolerance range, which is determined based on a regression line over the judgment time range.

[0010] The abnormality detection unit may detect a capacitor abnormality based on a first regression line derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing during a first judgment time range during discharge, and may also detect a capacitor abnormality based on a second regression line derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing during a second judgment time range during discharge.

[0011] After the charging unit applies a voltage to the capacitor with a first polarity to perform first polarity charging, the discharging unit performs first polarity discharge of the capacitor, and after the charging unit applies a voltage to the capacitor with a second polarity to perform second polarity charging, the discharging unit performs second polarity discharge of the capacitor, the current measuring unit measures the first polarity discharge current, which is the current of the capacitor during first polarity discharge, and measures the second polarity discharge current, which is the current of the capacitor during second polarity discharge, and the abnormality detection unit may detect an abnormality in the capacitor based on a first polarity regression line derived from the logarithm of the measured value of the first polarity discharge current in a first judgment time range during first polarity discharge and the logarithm of the measurement timing of the first polarity discharge current, and may also detect an abnormality in the capacitor based on a second polarity regression line derived from the logarithm of the measured value of the second polarity discharge current in a second judgment time range during second polarity discharge and the logarithm of the measurement timing of the second polarity discharge current.

[0012] Another aspect of this disclosure relates to an inspection method comprising the steps of: charging a capacitor; discharging a capacitor; continuously measuring the current of the capacitor during discharge; and detecting an abnormality in the capacitor based on a regression line derived from the logarithm of the measured current values ​​within a judgment time range during discharge and the logarithm of the timing of the current measurements. [Effects of the Invention]

[0013] According to this disclosure, it is advantageous for accurately detecting abnormalities in capacitors. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic perspective view of an example of an electronic component inspection system. [Figure 2] Figure 2 is a front view of the inspection system shown in Figure 1. [Figure 3] Figure 3 shows an example of the configuration of an inspection device. [Figure 4] Figure 4 is a circuit diagram showing an example of the charging and discharging sections (electrical circuits). [Figure 5]FIG. 5 is a graph (linear graph) showing an example of the measurement results of the leakage current of an electronic component (capacitor) during charging. [Figure 6] FIG. 6 is a graph (log-log graph) showing an example of the measurement results of the leakage current of an electronic component during charging, and is a graph for explaining the first charging abnormality detection method. [Figure 7] FIG. 7 is a graph (log-log graph) showing an example of the measurement results of the leakage current of an electronic component during charging, and is a graph for explaining the second charging abnormality detection method. [Figure 8] FIG. 8 is a graph (log-log graph) showing an example of the measurement results of the leakage current of an electronic component during discharging, and is a graph for explaining the first discharging abnormality detection method. [Figure 9] FIG. 9 is a graph (log-log graph) showing an example of the measurement results of the leakage current of an electronic component during discharging, and is a graph for explaining the second discharging abnormality detection method. [Figure 10] FIG. 10 is a log-log graph of "charging time - measured current" showing an example of the general electrical characteristics of a capacitor. [Figure 11] FIG. 11 is a log-log graph of "discharging time - measured current" showing an example of the general electrical characteristics of a capacitor. [Figure 12] FIG. 12 is a flowchart showing an example of an inspection method for detecting an abnormality in an electronic component (capacitor).

Embodiments for Carrying Out the Invention

[0015] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

[0016] In the following description, the electronic component W to be inspected may be the capacitor itself or an electronic component including the capacitor as a component. Also, the specific type of the capacitor to be inspected is not limited, and the following technology can be applied to MLCC, tantalum capacitors, or other general capacitors.

[0017] [Inspection System] Figure 1 is a schematic perspective view of an example of an electronic component inspection system 10. Figure 2 is a front view of the inspection system 10 shown in Figure 1. Note that in Figure 2, for ease of understanding, some of the components shown in Figure 1 (for example, the supply feeder 18, the electronic component supply unit 19, and the control unit 55) are omitted from the illustration.

[0018] The inspection system 10 shown in Figures 1 and 2 comprises a structure 10A, an index table 11 provided on the inclined surface 10a of the structure 10A, an inspection device 13, an electronic component discharge section 14, a discharge path 15, and a recovery device 16.

[0019] The index table 11 has a disc shape and is provided to rotate intermittently around a rotation axis 11a, and has a number of pockets 12 for accommodating electronic components to be inspected. The number of pockets 12 form multiple rows (e.g., 16 rows) in the radial direction of the index table 11, and in each row, the number of pockets 12 are arranged at equal angular intervals in the circumferential direction of the index table 11.

[0020] The index table 11 is covered from both the front and back sides by an index table cover 60. The front side index table cover 60 includes a first front cover 61, a second front cover 62, and a third front cover 63, which are arranged adjacent to each other with gaps in between. A number of electronic components to be inspected are supplied from the supply feeder 18 to the electronic component supply unit 19, and from the electronic component supply unit 19 to the pockets 12 via the index table cover 60 (the first front cover 61 in the example shown in Figures 1 and 2).

[0021] The inspection device 13 performs electrical testing of the electronic components housed in each pocket 12. While the inspection device 13 in this example can perform electrical testing in a normal temperature environment (e.g., 5°C to 35°C), it can also perform electrical testing while actively applying a thermal load (e.g., a thermal load of approximately 100°C to 170°C) to each electronic component, as described later. A specific configuration example of the inspection device 13 will be described later (see Figure 3).

[0022] The electronic component discharge unit 14 discharges electronic components that have undergone electrical inspection by the inspection device 13 to the recovery device 16 via the discharge path 15, for example, using compressed air. The recovery device 16 has multiple recovery boxes (six recovery boxes in the example shown in Figures 1 and 2). The electronic component discharge unit 14 sends each electronic component from the pocket 12 (index table 11) to the corresponding recovery box according to the result of the electrical inspection. The electronic component discharge unit 14 operates under the control of the control unit 55 so that electronic components determined to be normal and electronic components determined to have abnormalities are discharged to separate recovery boxes. The electronic component discharge unit 14 may also discharge electronic components to separate recovery boxes according to the type and degree of abnormality based on the result of the electrical inspection, or according to conditions other than the result of the electrical inspection.

[0023] According to the inspection system 10 described above, with the electronic components to be inspected stored in each pocket 12, the index table 11 is intermittently rotated in the clockwise direction as shown in Figures 1 and 2, so that the electronic components W in each pocket 12 are gradually transported downstream. The electronic components W in each pocket 12 are subjected to electrical inspection by the inspection device 13 at inspection positions along the transport path, and are sorted and collected by the electronic component discharge unit 14, discharge path 15, and recovery device 16 according to the results of the inspection.

[0024] The inspection system 10 shown in Figures 1 and 2 above can be realized based on known technology, and further specific explanation of the configuration of the inspection system 10 is omitted. The inspection system 10 of this embodiment may, for example, be configured similarly to the apparatus disclosed in Japanese Patent Application Publication No. 2023-5282.

[0025] [Inspection equipment] Figure 3 shows an example configuration of the inspection device 13. In Figure 3, some elements (for example, the probe holder 40 and the electrode unit 35) are shown in cross-section. Although the index table 11 (including the pockets 12) and other components are omitted from the illustration in Figure 3, each electronic component W shown in Figure 3 is housed in its corresponding pocket 12 and is intermittently stopped at inspection positions during transport by the index table 11.

[0026] The inspection device 13 shown in Figure 3 comprises multiple probe units 30, probe holders 40, and electrode units 35.

[0027] The number of probe units 30 is not limited, but a number of probe units 30 is provided that corresponds to the number of electronic components W to be inspected simultaneously (for example, the number of pockets 12 arranged radially on the index table 11). Each probe unit 30 has a probe 31, a compression spring 32, and a probe base 33. The probe 31, compression spring 32, and probe base 33 all contain an electrical conductor having high conductivity, and preferably have high thermal conductivity. The probe base 33 is electrically connected to the electrical circuit 50. The compression spring 32 is located between the probe 31 and the probe base 33 and is electrically connected to each of the probe 31 and the probe base 33. The probe 31 is supported by the probe holder 40 so as to partially protrude from the probe holder 40, allowing it to move back and forth while receiving an elastic force from the compression spring 32.

[0028] Each probe holder 40 supporting a probe unit 30 has a laminated structure including holder bodies 41a, 41b, 41c, and 41d, sheet materials 42a and 42b, and a probe heater 43. Sheet material 42a is provided between holder body 41a and holder body 41b, a probe heater 43 is provided between holder body 41b and holder body 41c, and sheet material 42b is provided between holder body 41c and holder body 41d.

[0029] The holder bodies 41a, 41b, 41c, and 41d are made of a material with relatively low thermal conductivity and electrical conductivity, such as photoveil material. On the other hand, the sheet materials 42a and 42b are made of a material with relatively high thermal conductivity and electrical conductivity, such as graphite material. The probe heater 43 is capable of generating heat under the control of the control unit 55 and is made of a rubber heater, for example. The heat from the probe heater 43 is efficiently transferred to each probe unit 30 (especially the probe 31) via the sheet materials 42a and 42b.

[0030] The electrode unit 35 has a laminated structure including an electrode 36, an electrode base 37, and an electrode heater 38. The electrode 36 is electrically connected to the electrical circuit 50. The electrode base 37 supports the electrode 36. The electrode heater 38 is provided so as to be covered by the electrode base 37 on both its front and back sides, and is capable of generating heat under the control of the control unit 55, and is composed of, for example, a rubber heater. Heat from the electrode heater 38 is transferred to the electrode 36 via the electrode base 37. From the viewpoint of efficiently heating the electrode 36 with the electrode heater 38, it is preferable that the electrode base 37 (particularly the portion located between the electrode heater 38 and the electrode 36) be made of a material with excellent heat conductivity.

[0031] The electrical circuit 50 is connected to each probe unit 30 (probe base 33 in the example shown in Figure 3) and electrode 36. While the probe 31 is away from the electronic component W to be inspected, the probe unit 30, electronic component W, electrode unit 35 (especially electrode 36), and electrical circuit 50 as a whole form an open circuit. On the other hand, when the electronic component W to be inspected is sandwiched between the probe 31 and electrode 36 and the probe 31 and electrode 36 come into contact with the electronic component W, a closed circuit is formed including the probe unit 30, electronic component W, electrode unit 35 (especially electrode 36), and electrical circuit 50.

[0032] In this example, the electrical circuit 50 functions as a charging unit 51A that applies voltage to charge the electronic component W (capacitor) under the control of the control unit 55, and a discharging unit 51B that discharges the electronic component W (capacitor). It also functions as a current measuring unit 52 that can continuously measure the current of the electronic component W (capacitor) during charging and discharging. In particular, the electrical circuit 50 (charging unit 51A), which is provided as part of the inspection system 10, is configured to apply a relatively large electrical load to the electronic component W under inspection. The magnitude of such an electrical load can be changed by the control unit 55 controlling the electrical circuit 50 (charging unit 51A), and for example, a DC voltage of several times the rated voltage of the electronic component W (e.g., 2.5 times) may be applied to the electronic component W.

[0033] The control unit 55 functions as an abnormality detection unit that detects abnormalities in each electronic component W (especially capacitors) based on the measurement results of the electrical circuit 50 (current measurement unit 52). Specific examples of methods for detecting abnormalities in each electronic component W by the control unit 55 will be described later.

[0034] According to the inspection device 13 described above, while the index table 11 is intermittently stopped, the electronic components W in each pocket 12 (see Figure 1) located at the inspection position are sandwiched between the electrode 36 and the corresponding probe 31. When the electronic components W are sandwiched between the electrode 36 and the probe 31, the electrode unit 35 and / or each probe unit 30 (and thus the probe holder 40) may be moved by a device (not shown) so that the electrode 36 and the probe 31 are brought closer to each other from a relatively separated state.

[0035] Then, an inspection voltage is applied to the electronic component W sandwiched between the electrode 36 and the probe 31 by the electrical circuit 50, which functions as a charging unit 51A, and the minute current (leakage current: charging current) flowing through the electronic component W is measured by the electrical circuit 50, which functions as a current measuring unit 52. In this way, the leakage current of the electronic component W while it is being charged is continuously measured, and the results of this measurement are sent from the electrical circuit 50 to the control unit 55.

[0036] After charging, the electronic component W, which is sandwiched between the electrode 36 and probe 31, is connected to a resistor by the electrical circuit 50, which functions as a discharge unit 51B, and discharged. The minute current (leakage current: discharge current) flowing through the electronic component W is measured by the electrical circuit 50, which functions as a current measuring unit 52. In this way, the leakage current of the electronic component W during discharge is continuously measured, and the results of this measurement are sent from the electrical circuit 50 to the control unit 55.

[0037] While continuous measurement of the leakage current of electronic component W can be performed at any time interval, from the viewpoint of improving the accuracy of determining whether or not there is an abnormality in electronic component W, it is preferable to continuously measure the leakage current of electronic component W at the shortest possible time intervals. With general measuring devices, the leakage current of electronic component W is usually measured at time intervals of about 10 ms to 100 ms. On the other hand, the inspection system 10 of this embodiment can also continuously measure the leakage current of electronic component W at time intervals shorter than 10 ms, and by continuously measuring the leakage current of electronic component W at time intervals of 5 ms or less (more preferably 1 ms or less), it is possible to accurately detect abnormalities in electronic component W that are difficult to detect with normal measurements using general measuring devices.

[0038] Furthermore, when measuring the electrical characteristics (leakage current characteristics) of an electronic component W under a thermal load, the electrode heater 38 and / or probe heater 43 are heated to a desired temperature under the control of the control unit 55. This heats the electrode 36 and / or probe 31, and while the electrode 36 and probe 31 are in contact with the electronic component W, the charging, discharging, and leakage current measurement of the electronic component W can be performed, along with heating the electronic component W (application of a thermal load).

[0039] The control unit 55 determines whether or not there is an abnormality in each electronic component W based on the measurement results of the leakage current of each electronic component W provided by the electrical circuit 50.

[0040] Figure 4 is a circuit diagram showing an example of the charging section 51A and the discharging section 51B (electrical circuit 50).

[0041] In the electrical circuit 50 shown in Figure 4, the power supply 70 is connected to the electronic component (capacitor) W and the resistor 71 via the charge / discharge selector switch 72.

[0042] The power supply 70 is a variable power supply with adjustable output (e.g., output voltage). Polarity selector switches 73 are provided on both the positive and negative sides of the power supply 70. These two polarity selector switches 73 work in conjunction with each other to switch the wiring so that when one charge / discharge selector switch 72 is connected to the positive side of the power supply 70, the other charge / discharge selector switch 72 is connected to the negative side of the power supply 70.

[0043] Each charge / discharge selector switch 72 is provided between the electronic component W and the resistor 71, and is capable of selectively connecting the electronic component W to either the resistor 71 or the polarity selector switch 73 (and consequently the power supply 70).

[0044] A current limiting circuit 74 is provided between each charge / discharge selector switch 72 and the electronic component W. The current limiting circuit 74 limits the current (especially the maximum current) flowing through the circuit, allowing the current to increase in proportion to the voltage up to a certain applied voltage (hereinafter also referred to as the "limiting voltage"), but basically only allows a constant current (a predetermined maximum current) for applied voltages above the limiting voltage. By providing the current limiting circuit 74, it is possible to prevent currents exceeding a specified maximum current value (for example, the maximum current value defined in standards such as JIS (Japanese Industrial Standards)) from flowing through the circuit.

[0045] The charge / discharge selector switch 72 and the polarity selector switch 73 are switched by the control unit 55 (see Figure 3). That is, under the control of the control unit 55, the connection target of the charge / discharge selector switch 72 is switched between the polarity selector switch 73 (and consequently the power supply 70) and the resistor 71, thereby switching the processing between charging and discharging of the electronic component W. Also, under the control of the control unit 55, the connection target of the polarity selector switch 73 is switched between one charge / discharge selector switch 72 and the other charge / discharge selector switch 72, thereby switching the polarity of the applied voltage applied to the electronic component (capacitor) W.

[0046] In this way, the control unit 55 can appropriately switch the charge / discharge switching switch 72 and the polarity switching switch 73 to switch between the charging abnormality detection process (see Figures 6 and 7 below) and the discharge abnormality detection process (see Figures 8 and 9 below), or to switch between the first polarity charging process and the second polarity charging process (see Figure 12 below).

[0047] [Testing Method] Figure 5 is a graph (real number graph) showing an example of the measurement results of the leakage current of an electronic component W (capacitor) during charging. The X axis of Figure 5 shows the charging time (milliseconds (ms)), which is the elapsed time from the start of measurement (origin (O)), and the Y axis shows the measured value of the leakage current of the electronic component W (amperes (A)).

[0048] Figure 5 shows the measurement results of the leakage current of a normal electronic component (i.e., a "good product") without any abnormalities and the measurement results of the leakage current of an electronic component with abnormalities (i.e., a "defective product") when an electronic component W (capacitor) is charged by applying a constant DC voltage to it.

[0049] The inventors of this case have conducted extensive research on the behavior of the electrical characteristics (particularly leakage current characteristics) of capacitors (e.g., MLCCs) during charging and discharging, and have newly discovered that capacitors may exhibit temporary abnormal behavior during charging and / or discharging (see "Ab" in Figure 5).

[0050] Such abnormal behavior can be detected by changes in the measured leakage current of the capacitor, but this is not always constant, and the amount of change may be small. Furthermore, the inventors of this case have newly discovered that there are capacitors that exhibit abnormal behavior for a certain period of time (e.g., tens of milliseconds to several seconds) before returning to normal behavior and behaving like a good product thereafter.

[0051] Conventional testing equipment that detects capacitor abnormalities based on the measured peak value of leakage current is suitable for detecting abnormalities where the leakage current suddenly increases, but is not necessarily suitable for detecting abnormalities where the leakage current decreases. Furthermore, conventional testing equipment is not always sufficient for capacitors that have an abnormality where the leakage current is unstable for some reason, even though the insulation of the capacitor has not deteriorated.

[0052] Furthermore, while the capacitance of MLCCs has been increasing in recent years, this has led to a tendency for the ceramic layer of MLCCs to become thinner, making it difficult to apply high voltages to MLCCs for screening. Therefore, there is a need for technology that can achieve highly reliable screening while keeping the applied voltage to MLCCs (capacitors) low.

[0053] For example, the device described in Patent Document 1 detects sharp, pulse-like abnormal currents (leakage currents) that occur in a capacitor during charging. While such a device as described in Patent Document 1 is effective when the leakage current during charging exhibits stable behavior, it is difficult to reliably detect abnormal currents when the leakage current changes relatively rapidly per unit time. Furthermore, the device described in Patent Document 1 cannot detect abnormalities where the leakage current of the capacitor decreases.

[0054] Furthermore, the apparatus described in Patent Document 2 determines the quality of a capacitor based on whether the evaluation function, determined from the measured current value and the standard selection current value of the capacitor, draws a curve that is convex in terms of the upper or lower end. However, as also described in Patent Document 2 (see paragraph 0012), the apparatus in Patent Document 2 treats temporary changes in the measured current value of the capacitor as noise and does not detect them as abnormalities. Also, the apparatus in Patent Document 1 cannot detect abnormalities such as a reduction in the leakage current of a capacitor.

[0055] Based on the above findings, the inventors have conducted further research and discovered a new technology that can effectively and accurately detect capacitor abnormalities that cannot be detected by conventional devices. Specifically, a new method has been discovered for accurately detecting capacitor abnormalities based on a regression line derived from the logarithm of the measured current (leakage current) of the electronic component W (capacitor) within a judgment time range during charging and / or discharging, and the logarithm of the measurement timing of said current. According to this method, abnormal behavior exhibited temporarily by an abnormal capacitor during charging and / or discharging can be detected with high accuracy. In particular, even if the amount of change in abnormal behavior is small, or even if the abnormal behavior lasts for only a limited time (e.g., tens of milliseconds to a few seconds), such abnormal behavior can be detected with high accuracy.

[0056] While various variations of such anomaly detection methods are conceivable, all of them are capable of detecting abnormal behavior of capacitors based on a regression line. Typical examples of such anomaly detection methods are shown below, but this disclosure also includes anomaly detection methods that utilize a regression line in a form different from the typical examples shown below.

[0057] First, we will explain the method for detecting abnormalities in the electronic component W (capacitor) during charging (see Figures 6-7), and then we will explain the method for detecting abnormalities in the electronic component W (capacitor) during discharge (Figures 8-9).

[0058] [First charging anomaly detection method] Figure 6 is a graph (log-log graph) showing an example of the measurement results of the leakage current of electronic component W during charging, and is a graph used to explain the first charging abnormality detection method. The X and Y axes in Figure 6 are based on logarithmic scales. The X axis of Figure 6 shows the charging time (milliseconds), which is the elapsed time from the start of measurement (origin (O)), on a logarithmic scale, and the Y axis shows the measured value (amperes) of the leakage current of electronic component W on a logarithmic scale.

[0059] Figure 6 shows the measurement results of the leakage current of a normal electronic component (i.e., a "good product") and an electronic component with an abnormality (i.e., a "defective product") when a constant DC voltage is applied to the electronic component W (capacitor) to charge it. Figure 6 also shows the "regression line Lr" obtained from the measurement results of the good and defective products based on the least squares method.

[0060] According to the inspection method based on the first charging abnormality detection method, the charging process, the current measurement process, and the abnormality detection process are performed under the control of the control unit 55.

[0061] In the charging process, the electronic component W (capacitor) is sandwiched between the probe 31 and electrode 36 shown in Figure 3, and a voltage is applied by the electrical circuit 50 (charging section 51A) to charge it. In the current measurement process, the current of the electronic component W (capacitor leakage current) during charging is continuously measured by the electrical circuit 50 (current measurement section 52). Thus, the current measurement process and the charging process are performed in parallel.

[0062] In the abnormality detection process, the control unit 55 (abnormality detection unit) detects abnormalities in the electronic component W (capacitor) based on a regression line Lr derived from the logarithm of the measured leakage current values ​​and the logarithm of the measurement timing of the leakage current during the determination time range Tv while charging. More specifically, the control unit 55 detects abnormalities in the electronic component W based on the degree of agreement between the logarithm of the measured leakage current values ​​and the logarithm of the measurement timing and the regression line Lr.

[0063] The "judgment time range Tv" referred to here is a time range suitable for determining whether or not there is an abnormality in the electronic component W. Specifically, it is set to a time range in which the degree of agreement between the measurement results of good products and the regression line Lr is high. The optimal judgment time range Tv is determined under the influence of the leakage current characteristics of the electronic component W and the voltage applied to the electronic component W. For example, it may be set to a time range of 200ms to 1500ms after the start of charging (see the origin "O" in Figure 6).

[0064] The degree of agreement between the logarithm of the leakage current measurement and the logarithm of the measurement timing and the regression line Lr is typically calculated as the coefficient of determination based on the least squares method. The specific method for calculating the coefficient of determination is not limited, and it is possible to calculate the coefficient of determination using known formulas.

[0065] For example, if the electronic component W is a good product, the "degree of agreement between the logarithm of the measured leakage current and the logarithm of the measurement timing and the regression line Lr" will be relatively high, and the value of the coefficient of determination (coefficient of determination) based on the least squares method will also be relatively large. If the coefficient of determination for the case where the logarithm of the measured leakage current and the logarithm of the measurement timing perfectly match the regression line Lr is expressed as "100%", then the coefficient of determination for a good electronic component W can be, for example, 95.0% or higher (99.0% or higher as an example).

[0066] On the other hand, if the electronic component W is defective, the "degree of agreement between the logarithm of the measured leakage current and the logarithm of the measurement timing and the regression line Lr" will be relatively low, and the value of the coefficient of determination will also be relatively small, for example, it may be less than 95.0% (for example, less than 99.0%).

[0067] As described above, the electronic component W being inspected can be classified as good or defective based on the coefficient of determination. However, the threshold of the coefficient of determination used as the classification criterion for good and defective products is set appropriately according to the actual tolerance for abnormalities. In other words, the closer the threshold is to "100%", the stricter the judgment of whether or not there is an abnormality becomes, and even minor abnormalities are not tolerated. As a result, the proportion of electronic components W that are judged as defective tends to increase.

[0068] Therefore, the higher the requirement for reliability regarding the electrical characteristics (leakage current characteristics) of the electronic component W, the closer the threshold of the coefficient of determination, which is used as the classification criterion for good and defective products, is set to a value close to "100%". In order to meet the high level of reliability required in recent advanced technologies, the threshold of the coefficient of determination may need to be set to a value of, for example, "99.0%" or higher.

[0069] Thus, the "degree of agreement between the logarithm of the measured leakage current and the logarithm of the measurement timing and the regression line Lr" represents the linearity of the logarithm of the measured leakage current and the logarithm of the measurement timing, and can be expressed as a coefficient of determination based on the least squares method. However, the "degree of agreement between the logarithm of the measured leakage current and the logarithm of the measurement timing and the regression line Lr" may also be determined based on any other method that can directly or indirectly evaluate the linearity on the log-log graph of "charging time - measured current".

[0070] For example, the control unit 55 (anomaly detection unit) may determine the "degree of inconsistency" between the logarithm of the measured leakage current and the logarithm of the measurement timing with respect to the regression line Lr using any method, and detect an anomaly in the electronic component W based on this degree of inconsistency. Alternatively, the control unit 55 (anomaly detection unit) may extract the measured leakage current data of the electronic component W under inspection only for a certain time range (judgment time range Tv) during the charging time. In this case, the control unit 55 may detect an anomaly in the electronic component W based on the regression line Lr derived from the logarithm of the extracted measured leakage current and the logarithm of the measurement timing of the leakage current.

[0071] The control unit 55 controls the electronic component discharge unit 14 based on the results of the inspection including the series of steps described above, and discharges the electronic components W that are determined to be abnormal and the electronic components W that are not determined to be abnormal to separate collection boxes of the collection device 16 via the discharge path 15.

[0072] [Second charging anomaly detection method] In the following explanation of the second charging anomaly detection method, a detailed explanation of the same process as the first charging anomaly detection method described above (see Figure 6) will be omitted.

[0073] Figure 7 is a graph (log-log graph) showing an example of the measurement results of the leakage current of electronic component W during charging, and is a graph used to explain the second charging abnormality detection method. The X and Y axes in Figure 7 are represented by logarithmic scales. The X axis of Figure 7 shows the charging time (milliseconds), which is the elapsed time from the start of measurement (origin (O)), on a logarithmic scale, and the Y axis shows the measured value (amperes) of the leakage current of electronic component W on a logarithmic scale.

[0074] Figure 7 shows the measurement results for good and defective electronic components, along with the regression line Lr obtained based on the measurement results for good and defective components. Furthermore, Figure 7 shows the upper limit B1 and lower limit B2 of the current tolerance range.

[0075] In the inspection method based on the second charging anomaly detection method, a charging process, a current measurement process, and an anomaly detection process are also performed, and in particular, the charging process and the current measurement process are performed in the same manner as in the inspection method based on the first charging anomaly detection method described above.

[0076] However, in the abnormality detection step based on the second charging abnormality detection method, the control unit 55 (abnormality detection unit) determines whether the logarithm of the measured leakage current of the electronic component W in the determination time range Tv falls within the current tolerance range determined with respect to the regression line Lr. That is, an abnormality in the electronic component W (capacitor) is detected based on the relationship between the logarithm of the measured leakage current and at least one of the upper limit B1 and lower limit B2 of the current tolerance range determined with respect to the regression line Lr over the determination time range Tv.

[0077] In the log-log graph of Figure 7, the region between the line indicated by the sign "B1" (upper limit) and the line indicated by the sign "B2" (lower limit) corresponds to the current tolerance range, and the regression line Lr lies within this region (current tolerance range) during the judgment time range Tv.

[0078] As described above, the electronic component W being inspected can be classified as good or defective based on the current tolerance range (upper limit B1 and lower limit B2). However, the upper limit B1 and lower limit B2 that define the current tolerance range correspond to thresholds that serve as the classification criteria for good and defective products, and are set appropriately according to the actual tolerance level for abnormalities. In other words, the closer the upper limit B1 and lower limit B2 of the current tolerance range are to the regression line Lr, the stricter the judgment of whether or not there is an abnormality becomes, and even minor abnormalities are no longer tolerated, and the proportion of electronic components W that are judged as defective tends to increase. Therefore, the higher the requirement for reliability of the normality of the electrical characteristics (leakage current characteristics) of the electronic component W, the closer the upper limit B1 and lower limit B2 of the current tolerance range that serve as the classification criteria for good and defective products should be set to values ​​closer to the regression line Lr.

[0079] There are no specific methods for determining the upper and lower limits B1 and B2 of the current tolerance range. For example, the difference between the regression line Lr and the measured current (see the Y-axis in Figure 7) may be the same or different between the upper and lower limits B1 and B2 of the current tolerance range. Also, the difference between the regression line Lr and the upper or lower limit B1 or B2 of the current tolerance range with respect to the measured current may be the same or different across the entire judgment time range Tv. Therefore, in the log-log graph of "charging time - measured current" (see Figure 7), the lines indicating the upper limit B1 and lower limit B2 of the current tolerance range may be parallel or disparallel to the regression line Lr.

[0080] Furthermore, the upper and lower limits B1 and B2 of the current tolerance range may be determined from the values ​​of the regression line Lr (the Y-axis value relating to the measured current) at multiple discrete time timings selected from the judgment time range Tv. For example, the upper and lower limits B1 and B2 of the current tolerance range may be determined based on the regression line Lr for two points, the "start time timing (start point)" and the "end time timing (end point)" of the judgment time range Tv. In this case, in the log-log graph of "charging time - measured current" (see Figure 7), the upper limit B1 of the current tolerance range over the entire judgment time range Tv may be determined by a line passing through these two points (start point and end point) relating to the upper limit B1 of the current tolerance range. Similarly, in the log-log graph of "charging time - measured current", the lower limit B2 of the current tolerance range over the entire judgment time range Tv may be determined by a line passing through these two points (start point and end point) relating to the lower limit B2 of the current tolerance range.

[0081] Furthermore, the control unit 55 (abnormality detection unit) may set only one of the upper limit B1 and lower limit B2 of the current tolerance range to a value different from the regression line Lr. In this case, the other of the upper limit B1 and lower limit B2 of the current tolerance range may be set to the same value as the regression line Lr.

[0082] In the abnormality detection step described above, the control unit 55 can determine that there is no abnormality in the electronic component W if the entire measured current of the electronic component W in the determination time range Tv is within the current tolerance range (for example, including the boundaries (upper limit B1 and lower limit B2)). On the other hand, if at least a portion of the measured current of the electronic component W in the determination time range Tv is outside the current tolerance range (for example, not including the boundaries (upper limit B1 and lower limit B2)), the control unit 55 can determine that there is an abnormality in the electronic component W.

[0083] The control unit 55 then controls the electronic component discharge unit 14 based on the results of the inspection, including the series of steps described above, and discharges the electronic component W that was determined to be abnormal and the electronic component W that was not determined to be abnormal into separate collection boxes of the collection device 16 via the discharge path 15.

[0084] Next, we will explain a method for detecting abnormalities in the electronic component W (capacitor) during discharge (Figures 8-9).

[0085] [First method for detecting discharge anomalies] In the following description of the first discharge anomaly detection method, detailed explanations of processes similar to those described above for the first charging anomaly detection method (see Figure 6) and the second charging anomaly detection method (see Figure 7) will be omitted.

[0086] Figure 8 is a graph (log-log graph) showing an example of the measurement results of the leakage current of electronic component W during discharge, and is a graph used to explain the first discharge abnormality detection method. The X and Y axes in Figure 8 are represented by logarithmic scales. The X axis of Figure 8 shows the discharge time (milliseconds), which is the elapsed time from the start of measurement (origin (O)), on a logarithmic scale, and the Y axis shows the measured value (amperes) of the leakage current of electronic component W on a logarithmic scale.

[0087] Figure 8 shows the measurement results of the leakage current of an abnormal electronic component (i.e., a "defective product") when a resistor is connected to the electronic component W (capacitor) and discharge is performed. Figure 8 also shows the "regression line Lr" obtained from the measurement results based on the least squares method.

[0088] The first discharge abnormality detection method applies the current measurement and abnormality detection performed in the first charging abnormality detection method described above to the discharge of electronic component W instead of the charging of electronic component W. In other words, according to the inspection method based on the first discharge abnormality detection method, the discharge process, the current measurement process, and the abnormality detection process are performed under the control of the control unit 55.

[0089] In the discharge process, the electronic component W (capacitor) is sandwiched between the probe 31 and electrode 36 shown in Figure 3, and connected to the resistor 71 (see Figure 4) by the electrical circuit 50 (discharge section 51B) to discharge. In the current measurement process, the current of the electronic component W during discharge (capacitor leakage current) is continuously measured by the electrical circuit 50 (current measurement section 52). Thus, the current measurement process and the discharge process are performed in parallel.

[0090] In the abnormality detection process, the control unit 55 (abnormality detection unit) detects abnormalities in the electronic component W (capacitor) based on a regression line Lr derived from the logarithm of the measured leakage current values ​​and the logarithm of the measurement timing of the leakage current during the judgment time range Tv while discharge. More specifically, the control unit 55 detects abnormalities in the electronic component W based on the degree of agreement between the logarithm of the measured leakage current values ​​and the logarithm of the measurement timing and the regression line Lr.

[0091] The "judgment time range Tv" is preferably set to a time range in which the degree of agreement between the measurement results of good products and the regression line Lr is high. For example, in the initial stage of discharge, the "judgment time range Tv" may be set to a time range of 20ms to 100ms after the start of discharge (see the origin "O" in Figure 8). Alternatively, when the discharge current has decreased to a certain extent, the "judgment time range Tv" may be set to a time range of 200ms to 1500ms after the start of discharge. However, these time ranges are merely examples of the "judgment time range Tv", and the "judgment time range Tv" may be set to any other time range, for example, within the range of 10ms to 20ms after the start of discharge.

[0092] The control unit 55 controls the electronic component discharge unit 14 based on the results of the inspection including the series of steps described above, and discharges the electronic components W that are determined to be abnormal and the electronic components W that are not determined to be abnormal to separate collection boxes of the collection device 16 via the discharge path 15.

[0093] [Second method for detecting discharge anomalies] In the following description of the second discharge anomaly detection method, detailed explanations of processes similar to those described above for the first charging anomaly detection method (see Figure 6), the second charging anomaly detection method (see Figure 7), and the first discharge anomaly detection method (see Figure 8) will be omitted.

[0094] Figure 9 is a graph (log-log graph) showing an example of the measurement results of the leakage current of electronic component W during discharge, and is a graph used to explain the second discharge abnormality detection method. The X and Y axes in Figure 9 are represented by logarithmic scales. The X axis of Figure 9 shows the discharge time (milliseconds), which is the elapsed time from the start of measurement (origin (O)), on a logarithmic scale, and the Y axis shows the measured value (amperes) of the leakage current of electronic component W on a logarithmic scale.

[0095] Figure 9 shows the measurement results for defective electronic components, along with the regression line Lr obtained based on the measurement results for both good and defective components. Furthermore, Figure 9 shows the upper limit B1 and lower limit B2 of the current tolerance range.

[0096] The second discharge anomaly detection method applies the current measurement and anomaly detection performed in the second charging anomaly detection method described above to the discharge of electronic component W instead of the charging of electronic component W. In other words, the inspection method based on the second discharge anomaly detection method also includes a discharge process, a current measurement process, and an anomaly detection process, and the discharge process and current measurement process in particular are performed in the same manner as in the inspection method based on the first discharge anomaly detection method described above.

[0097] However, in the abnormality detection step based on the second discharge abnormality detection method, the control unit 55 (abnormality detection unit) determines whether the logarithm of the measured leakage current of the electronic component W in the determination time range Tv falls within the current tolerance range determined with respect to the regression line Lr. That is, an abnormality in the electronic component W (capacitor) is detected based on the relationship between the logarithm of the measured leakage current and at least one of the upper limit B1 and lower limit B2 of the current tolerance range determined with respect to the regression line Lr over the determination time range Tv.

[0098] In the log-log graph of Figure 9, the region between the line indicated by the sign "B1" (upper limit) and the line indicated by the sign "B2" (lower limit) corresponds to the current tolerance range, and the regression line Lr lies within this region (current tolerance range) during the judgment time range Tv.

[0099] The upper limit B1 and lower limit B2 of the current tolerance range used in this discharge abnormality detection method are not limited in their specific determination method and may be determined in the same way as the upper limit B1 and lower limit B2 of the current tolerance range used in the second charging abnormality detection method described above (see Figure 7).

[0100] Therefore, the upper limit B1 and lower limit B2 of the current tolerance range may be determined from the values ​​of the regression line Lr (Y-axis values ​​related to the measured current) at multiple discrete time timings selected from the judgment time range Tv. Alternatively, the control unit 55 (abnormality detection unit) may set only one of the upper limit B1 and lower limit B2 of the current tolerance range to a value different from the regression line Lr. In this case, the other of the upper limit B1 and lower limit B2 of the current tolerance range may be set to the same value as the regression line Lr.

[0101] In the abnormality detection step described above, the control unit 55 can determine that there is no abnormality in the electronic component W if the entire measured current of the electronic component W in the determination time range Tv is within the current tolerance range (for example, including the boundaries (upper limit B1 and lower limit B2)). On the other hand, if at least a portion of the measured current of the electronic component W in the determination time range Tv is outside the current tolerance range (for example, not including the boundaries (upper limit B1 and lower limit B2)), the control unit 55 can determine that there is an abnormality in the electronic component W.

[0102] The control unit 55 then controls the electronic component discharge unit 14 based on the results of the inspection, including the series of steps described above, and discharges the electronic component W that was determined to be abnormal and the electronic component W that was not determined to be abnormal into separate collection boxes of the collection device 16 via the discharge path 15.

[0103] [Examples of Anomaly Detection Techniques] The first and second charging anomaly detection methods described above (see Figures 6 and 7), the first and second discharge anomaly detection methods (see Figures 8 and 9), or other charging anomaly detection methods or discharge anomaly detection methods based on the regression line Lr can be applied to the inspection method of the electronic component W as follows, thereby enabling accurate detection of anomalies in the electronic component W.

[0104] [Application Example 1] Figure 10 is a log-log graph of "charging time - measured current" showing an example of a typical electrical characteristic of a capacitor. Figure 11 is a log-log graph of "discharge time - measured current" showing an example of a typical electrical characteristic of a capacitor.

[0105] When a capacitor is charged by applying a constant DC voltage, the correlation between the logarithm of the charging time and the logarithm of the leakage current is not necessarily constant throughout the entire charging time. Instead, there are multiple stages (see "P1" to "P3" in Figure 10) that exhibit an inherent linearity (proportional relationship). In the example shown in Figure 10, there is a first stage P1 where the capacitor's leakage current is almost constant, a second stage P2 where the leakage current decreases sharply, and a third stage P3 where the leakage current decreases more sharply than in the first stage P1 but more gradually than in the second stage P2. In the log-log graph shown in Figure 10, "charging time - measured current" shows a proportional correlation in all stages from the first stage P1 to the third stage P3, but the rate of proportional correlation (i.e., the slope of linearity) of "charging time - measured current" differs among the stages from the first stage P1 to the third stage P3.

[0106] Similarly, when a resistor is connected to a capacitor and discharged, the correlation between the logarithm of the capacitor's discharge time and the logarithm of the leakage current is not necessarily constant throughout the entire discharge time, but rather there are multiple stages (see "P11" to "P13" in Figure 11) that show an inherent linearity (proportional relationship). In the example shown in Figure 11, there is a first stage P11 where the capacitor's leakage current is almost constant, a second stage P12 where the leakage current decreases sharply, and a third stage P13 where the leakage current decreases more sharply than in the first stage P11 but more gradually than in the second stage P12. In the log-log graph shown in Figure 11, "discharge time - measured current" shows a proportional correlation in all of the first to third stages P11 to P13, but the rate of proportional correlation (i.e., the slope of linearity) of "discharge time - measured current" differs among the first to third stages P11 to P13.

[0107] The control unit 55 (anomaly detection unit) can detect anomalies in the electronic component W (capacitor) at each stage by setting the judgment time range Tv and the regression line Lr for each stage.

[0108] For example, the control unit 55 can detect an abnormality in the electronic component W during the first determination time range based on a first regression line derived from the logarithm of the measured leakage current of the electronic component W during the first determination time range while charging and the logarithm of the measurement timing of the said leakage current. On the other hand, the control unit 55 can detect an abnormality in the electronic component W during the second determination time range based on a second regression line derived from the logarithm of the measured leakage current of the electronic component W during the second determination time range while charging and the logarithm of the measurement timing of the said leakage current.

[0109] By setting the "first judgment time range" and the "second judgment time range" to different stages (see the first stage P1, second stage P2, and third stage P3 in Figure 10), abnormalities in the electronic component W can be detected in each of the multiple stages. If there are three or more stages in the correlation between the capacitor charging time and leakage current, three or more judgment time ranges may be assigned to each stage.

[0110] For example, in the example shown in Figure 10, the first stage P1 may be set to "first judgment time range Tv1", the second stage P2 to "second judgment time range Tv2", and the third stage P3 to "third judgment time range Tv3". In this case, the first regression line Lr1 is determined based on the measurement results of the leakage current in the first judgment time range Tv1, the second regression line Lr2 is determined based on the measurement results of the leakage current in the second judgment time range Tv2, and the third regression line Lr3 is determined based on the measurement results of the leakage current in the third judgment time range Tv3. Then, using the anomaly detection method described above (see Figures 6 and 7), an anomaly in the electronic component W in the first judgment time range Tv1 can be detected based on the first regression line Lr1, an anomaly in the electronic component W in the second judgment time range Tv2 can be detected based on the second regression line Lr2, and an anomaly in the electronic component W in the third judgment time range Tv3 can be detected based on the third regression line Lr3.

[0111] Note that the "first judgment time range" and the "second judgment time range" may be set in a common stage. For example, the "first judgment time range" and the "second judgment time range" (and subsequent judgment time ranges) may be set in a single stage that occupies a relatively long time range (see stage 3 P3 in Figure 10).

[0112] Similarly, the control unit 55 can detect an abnormality in the electronic component W during the first determination time range based on a first regression line derived from the logarithm of the measured leakage current of the electronic component W during the first determination time range during discharge and the logarithm of the measurement timing of the said leakage current. On the other hand, the control unit 55 can detect an abnormality in the electronic component W during the second determination time range during discharge based on a second regression line derived from the logarithm of the measured leakage current of the electronic component W during the second determination time range during discharge and the logarithm of the measurement timing of the said leakage current.

[0113] By setting the "first judgment time range" and the "second judgment time range" to different stages (see the first stage P11, second stage P12, and third stage P13 in Figure 11), abnormalities in the electronic component W can be detected in each of the multiple stages. If there are three or more stages in the correlation between the capacitor discharge time and leakage current, three or more judgment time ranges may be assigned to each stage.

[0114] For example, in the example shown in Figure 11, the first stage P11 may be set to "first judgment time range Tv11", the second stage P12 to "second judgment time range Tv12", and the third stage P13 to "third judgment time range Tv13". In this case, the first regression line Lr11 is determined based on the measurement results of the leakage current in the first judgment time range Tv11, the second regression line Lr12 is determined based on the measurement results of the leakage current in the second judgment time range Tv12, and the third regression line Lr13 is determined based on the measurement results of the leakage current in the third judgment time range Tv13. Then, using the anomaly detection method described above (see Figures 8 and 9), anomalies in the electronic component W can be detected in the first judgment time range Tv11 based on the first regression line Lr11, anomalies in the electronic component W can be detected in the second judgment time range Tv12 based on the second regression line Lr12, and anomalies in the electronic component W can be detected in the third judgment time range Tv13 based on the third regression line Lr13.

[0115] Note that the "first judgment time range" and the "second judgment time range" may be set in a common stage. For example, the "first judgment time range" and the "second judgment time range" (and subsequent judgment time ranges) may be set in a single stage that occupies a relatively long time range (see stage 3, P13 in Figure 11).

[0116] [Application Example 2] The inspection device 13 may perform multiple electrical tests on each electronic component W. Such multiple electrical tests may include two electrical tests in which the polarity (direction of the positive and negative poles) of the current (DC current) applied to each electronic component W is different.

[0117] In other words, in the electrical circuit 50 (see Figure 3), the charging unit 51A may apply a voltage to the electronic component W (capacitor) with a first polarity to perform first polarity charging, and then the discharging unit 51B may connect the electronic component W to the resistor 71 (see Figure 4) to perform first polarity discharge. Alternatively, after the first polarity charging and first polarity discharge, the charging unit 51A may apply a voltage to the electronic component W with a second polarity, which is the opposite polarity to the first polarity, to perform second polarity charging, and then the discharging unit 51B may connect the electronic component W to the resistor 71 (see Figure 4) to perform second polarity discharge.

[0118] In this case, the electrical circuit 50 (current measuring unit 52) ​​measures the first polarity charging current, which is the leakage current of the electronic component W during first polarity charging; the first polarity discharge current, which is the leakage current of the electronic component W during first polarity discharge; the second polarity charging current, which is the leakage current of the electronic component W during second polarity charging; and the second polarity discharge current, which is the leakage current of the electronic component W during second polarity discharge.

[0119] The control unit 55 (abnormality detection unit) can detect abnormalities in the electronic component W (capacitor) based on a first polarity regression line derived from the logarithm of the measured value of the first polarity charging current in the first determination time range during first polarity charging and the logarithm of the measurement timing of the first polarity charging current. The control unit 55 can also detect abnormalities in the electronic component W (capacitor) based on a second polarity regression line derived from the logarithm of the measured value of the second polarity charging current in the second determination time range during second polarity charging and the logarithm of the measurement timing of the second polarity charging current. Note that if a negative voltage is applied to the electronic component W (for example, in the case of second polarity charging), the measured value of the leakage current of the electronic component W (for example, second polarity charging current) will also be a negative value, so the regression line may be derived from the logarithm of the absolute value of the measured leakage current.

[0120] Similarly, the control unit 55 (abnormality detection unit) can detect abnormalities in the electronic component W (capacitor) based on a first polarity regression line derived from the logarithm of the measured value of the first polarity discharge current in the first judgment time range during the first polarity discharge and the logarithm of the measurement timing of the first polarity discharge current. The control unit 55 can also detect abnormalities in the electronic component W (capacitor) based on a second polarity regression line derived from the logarithm of the measured value of the second polarity discharge current in the second judgment time range during the second polarity discharge and the logarithm of the measurement timing of the second polarity discharge current. Note that if discharge occurs immediately after a negative voltage is applied to the electronic component W (for example, in the case of second polarity discharge), the measured value of the leakage current of the electronic component W (for example, second polarity discharge current) will also be a negative value, so the regression line may be derived from the logarithm of the absolute value of the measured leakage current.

[0121] The capacitor of electronic component W may exhibit unique electrical characteristics depending on the polarity of the applied current, and may show abnormal leakage current behavior only when a voltage of the first polarity or a voltage of the second polarity is applied. Even if the electronic component W under inspection has such polarity, abnormalities in the electronic component W can be reliably detected by performing electrical tests for both the first and second polarities, as in this application example.

[0122] The phenomenon described above, that "the capacitor of electronic component W may exhibit unique electrical characteristics depending on its polarity," can occur not only as electrical characteristics during charging but also as electrical characteristics during discharge. Therefore, it is preferable that the discharge abnormality detection (first polarity discharge abnormality detection; see Figures 8 and 9) is performed after the first polarity charging abnormality detection (first polarity charging abnormality detection; see Figures 6 and 7) is performed. In other words, it is preferable that the current measurement unit 52 measures the first polarity charging current, which is the current of electronic component W during first polarity charging, and then measures the first polarity discharge current, which is the current of electronic component W during first polarity discharge.

[0123] Furthermore, it is preferable that, after the above-mentioned detection of a charging abnormality during second-polarity charging (detection of a second-polarity charging abnormality; see Figures 6 and 7), a discharge abnormality detection (detection of a second-polarity discharge abnormality; see Figures 8 and 9) is performed. In other words, it is preferable that the current measuring unit 52 first measures the second-polarity charging current, which is the current of the electronic component W during second-polarity charging, and then measures the second-polarity discharge current, which is the current of the electronic component W during second-polarity discharge.

[0124] Figure 12 is a flowchart showing an example of an inspection method for detecting abnormalities in an electronic component W (capacitor). The flowchart in Figure 12 shows an example of the inspection flow performed by the inspection device 13 in a single inspection process. If the inspection process by the inspection device 13 is performed repeatedly, the inspection flow shown in Figure 12 is repeated.

[0125] In the example inspection system 10 shown in Figures 1 and 2, the index table 11 is intermittently rotated and stopped so that the multiple electronic components W to be inspected are positioned in the inspection location where the inspection device 13 is to be performed (particularly the area covered by the second front cover 62 (see probe unit 30 shown in Figure 3)). While the index table 11 is intermittently stopped, the inspection flow shown in Figure 12 is performed to determine whether each of the multiple electronic components W to be inspected is classified as a good product or a defective product.

[0126] Specifically, first, the first polarity charging process is performed simultaneously on multiple electronic components W to be inspected, while the leakage current of each electronic component W is measured (S1 in Figure 12). Based on the results of this measurement, it is determined whether or not there is a charging abnormality in each electronic component W (first polarity charging abnormality detection process; S2).

[0127] Subsequently, the discharge process (first polarity discharge process) of multiple electronic components W to be inspected, which have been charged with the first polarity, is performed simultaneously while the leakage current of each electronic component W is measured (S3). Based on the results of this measurement, it is determined whether or not there is a discharge abnormality in each electronic component W (first polarity discharge abnormality detection process; S4).

[0128] Subsequently, the second polarity charging process is performed simultaneously on multiple electronic components W that are subject to inspection after the first polarity discharge process, and the leakage current of each electronic component W is measured (S5). Based on the results of this measurement, it is determined whether or not there is a charging abnormality in each electronic component W (second polarity charging abnormality detection process; S6).

[0129] Subsequently, the discharge process (second polarity discharge process) of multiple electronic components W under inspection, which have been charged with the second polarity, is performed simultaneously while the leakage current of each electronic component W is measured (S7). Based on the results of this measurement, it is determined whether or not there is a discharge abnormality in each electronic component W (second polarity discharge abnormality detection process; S8).

[0130] Electronic component W in which an abnormality is detected in at least one of the above-mentioned series of abnormality detection processes (S2, S4, S6, S8) is classified as a defective product (Y in S9, S10). On the other hand, electronic component W in which no abnormality is detected in any of the above-mentioned series of abnormality detection processes (S2, S4, S6, S8) is classified as a good product (N in S9, S11).

[0131] In the example shown in Figure 12, the various abnormality detection processes (S2, S4, S6, S8) described above are performed in separate steps immediately after the measurement of the corresponding leakage currents of the multiple electronic components W under inspection. However, they may also be performed together in a single step (for example, step S9 shown in Figure 12). In this case, the "first polarity charging process and leakage current measurement (S1)", "first polarity discharge process and leakage current measurement (S3)", "second polarity charging process and leakage current measurement (S5)", and "second polarity discharge process and leakage current measurement (S7)" can be performed consecutively.

[0132] Furthermore, the various abnormality detection processes (S2, S4, S6, S8) and good / bad classification processes (S9, S10, S11) described above do not necessarily need to be performed while the multiple electronic components W to be inspected are located at the inspection position (the area covered by the second front cover 62 (see Figures 1 and 2)). In other words, the various abnormality detection processes (S2, S4, S6, S8) and good / bad classification processes (S9, S10, S11) can be performed before the discharge process in which the multiple electronic components W to be inspected are discharged to the corresponding recovery device 16 via the discharge path 15 at the discharge position (particularly the area covered by the third front cover 63 (see Figures 1 and 2)). Therefore, the various abnormality detection processes (S2, S4, S6, S8) and good / bad classification processes (S9, S10, S11) can be performed while the multiple electronic components W to be inspected are moving from the inspection position to the discharge position.

[0133] As explained above, according to the inspection device 13 and inspection method described above, an abnormality in the electronic component W (capacitor) can be detected based on a regression line Lr derived from the logarithm of the measured leakage current of the electronic component W in each judgment time range Tv during charging and discharging, and the logarithm of the measurement timing of the said leakage current.

[0134] In particular, even if an abnormal electronic component W exhibits abnormal behavior only temporarily during charging or discharging, the inspection device 13 and inspection method described above can appropriately detect the abnormality of such electronic component W. Furthermore, even if the leakage current behavior of the electronic component W is inconsistent and the amount of change in the leakage current is small, the inspection device 13 and inspection method described above can appropriately detect the abnormality of such electronic component W.

[0135] Furthermore, according to the inspection device 13 and inspection method described above, it is possible to detect not only abnormalities where the leakage current of the electronic component W increases, but also abnormalities where the leakage current decreases. In addition, even if the inspection voltage applied to the electronic component W under inspection is low, abnormalities in the electronic component W can be detected reliably.

[0136] Furthermore, even under normal conditions, electronic components W whose leakage current per unit time fluctuates relatively drastically may be subject to inspection. However, according to the second charging abnormality detection method (see Figure 7) and / or the second discharge abnormality detection method (see Figure 9) described above, it is possible to accurately detect abnormalities in such electronic components W. In other words, by determining the upper limit B1 and / or lower limit B2 of the current tolerance range considering the magnitude of the fluctuation in the leakage current under normal conditions of electronic components W, it is possible to detect the true "abnormality" of electronic components W while preventing the fluctuation in the leakage current under normal conditions from being detected as an "abnormality." Moreover, according to the second charging abnormality detection method and / or the second discharge abnormality detection method described above, it is also possible to detect "abnormalities in which the leakage current is unstable for some reason, even though the insulation properties of electronic components W (capacitors) have not deteriorated."

[0137] Furthermore, according to the inspection system 10 and inspection method described above, abnormalities in electronic components W during both charging and discharging can be appropriately detected. In particular, during charging, the capacity (influence) of the charging power supply is inevitably reflected in the abnormality detection results, but during discharging, since there is basically no influence (noise) from the charging power supply, the individual characteristics of the electronic components (capacitors) W tend to be more strongly reflected in the abnormality detection results. Therefore, inspection based on the discharge abnormality detection results can appropriately detect even minor or sudden abnormalities in electronic components W that are difficult to detect with normal inspections.

[0138] In particular, since the discharge abnormality detection process is performed after the corresponding charge abnormality detection process, it can also detect abnormalities in the electronic component W caused by the corresponding charge abnormality detection process.

[0139] Furthermore, when electronic component W is charged for inspection, it is usually discharged after charging for safety reasons. In other words, regardless of whether or not discharge abnormality detection is performed (or whether it is necessary), the charging and discharging processes of electronic component W are usually performed continuously. Therefore, even if discharge abnormality detection is performed in addition to charging abnormality detection, it is possible to ensure that the total time required for the detection process does not increase substantially, or only increases slightly, compared to when only charging abnormality detection is performed.

[0140] In the example shown in Figure 12 above, the charging abnormality detection process and the discharging abnormality detection process are performed together, but it is also possible that the charging abnormality detection process is performed but the discharging abnormality detection process is not, or that the charging abnormality detection process is not performed but the discharging abnormality detection process is performed.

[0141] As described above, the inspection device 13 of this embodiment includes a charging unit 51A that charges the electronic component (capacitor) W, a discharging unit 51B that discharges the electronic component W, a current measuring unit 52 that continuously measures the current of the electronic component W during discharge, and a control unit (abnormality detection unit) 55 that detects abnormalities in the electronic component W based on a regression line Lr relating to discharge characteristics derived from the logarithm of the measured current values ​​in the judgment time range Tv during discharge and the logarithm of the current measurement timing.

[0142] Furthermore, the current measurement unit 52 continuously measures the current of the electronic component W during charging, and the control unit 55 can detect abnormalities in the electronic component W based on a regression line Lr relating to charging characteristics derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing within the judgment time range Tv during charging.

[0143] Furthermore, the control unit 55 can detect abnormalities in the electronic component W based on the degree of agreement between the logarithm of the measured current and the logarithm of the measurement timing with respect to the regression line Lr.

[0144] Furthermore, the control unit 55 can detect abnormalities in the electronic component W based on the logarithmic relationship of the measured current with respect to at least one of the upper limit B1 and lower limit B2 of the current tolerance range, which is determined based on the regression line Lr over the judgment time range Tv.

[0145] Furthermore, the control unit 55 can detect abnormalities in the electronic component W based on a first regression line Lr11 derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing during a first determination time range Tv11 while discharge, and can also detect abnormalities in the electronic component W based on a second regression line Lr12 derived from the logarithm of the measured current values ​​and the logarithm of the current measurement timing during a second determination time range Tv12 while discharge.

[0146] After the charging unit 51A applies a voltage to the electronic component W with a first polarity to perform first polarity charging, the discharging unit 51B performs first polarity discharge of the electronic component W, and after the charging unit 51A applies a voltage to the electronic component W with a second polarity to perform second polarity charging, the discharging unit 51B performs second polarity discharge of the electronic component W, the current measuring unit 52 measures the first polarity discharge current, which is the current of the electronic component W during first polarity discharge, and measures the second polarity discharge current, which is the current of the electronic component W during second polarity discharge, and the control unit 55, It is possible to detect abnormalities in electronic component W based on the first polarity regression line Lr derived from the logarithm of the measured value of the first polarity discharge current in the first judgment time range Tv11 during the first polarity discharge and the logarithm of the measurement timing of the first polarity discharge current, and to detect abnormalities in electronic component W based on the second polarity regression line Lr derived from the logarithm of the measured value of the second polarity discharge current in the second judgment time range Tv12 during the second polarity discharge and the logarithm of the measurement timing of the second polarity discharge current.

[0147] Furthermore, the inspection method of this embodiment includes the steps of: charging the electronic component W; discharging the electronic component W; continuously measuring the current of the electronic component W during discharge; and detecting an abnormality in the electronic component W based on a regression line Lr derived from the logarithm of the measured current values ​​in the judgment time range Tv during discharge and the logarithm of the current measurement timing.

[0148] It should be noted that the embodiments and modifications disclosed herein are illustrative in all respects and should not be construed restrictively. The embodiments and modifications described above may be omitted, substituted, and modified in various ways without departing from the scope and spirit of the appended claims. For example, the embodiments and modifications described above may be combined in whole or in part, and other embodiments may be combined with the embodiments or modifications described above. Furthermore, the effects described herein are illustrative, and other effects may result.

[0149] The technical categories that embody the above-described technical concept are not limited. For example, the above-described technical concept may be embodied by a computer program that causes a computer to execute one or more steps included in a method for manufacturing or using the above-described device. Alternatively, the above-described technical concept may be embodied by a computer-readable, non-transitory recording medium on which such a computer program is recorded. [Explanation of Symbols]

[0150] 10 Inspection system, 10A Structure, 10a Inclined surface, 11 Index table, 11a Rotating shaft, 12 Pocket, 13 Inspection device, 14 Electronic component discharge section, 15 Discharge path, 16 Recovery device, 18 Supply feeder, 19 Electronic component supply section, 30 Probe unit, 31 Probe, 33 Probe base, 35 Electrode unit, 36 Electrode, 37 Electrode base, 38 Electrode heater, 40 Probe holder, 41a Holder body, 41b Holder body, 41c Holder body, 41d Holder body, 42a Sheet material, 42b Sheet material, 43 Probe heater, 50 Electrical circuit, 51A Charging section, 51B Discharging section, 52 Current measurement section, 55 Control section, 60 Index table cover, 61 First front cover, 62 Second front cover, 63 Third front cover, 70 Power supply, 71 Resistor, 72 Charge / Discharge selector switch, 73 Polarity selector switch, 74 Current limiting circuit, B1 Upper limit of current tolerance range, B2 Lower limit of current tolerance range, Tv Judgment time range, W Electronic component

Claims

1. A charging section that charges the capacitor, A discharge section that discharges the capacitor, A current measuring unit that continuously measures the current of the capacitor during discharge, An abnormality detection unit detects an abnormality in the capacitor based on a regression line relating to the discharge characteristics derived from the logarithm of the measured current values ​​within the determination time range during discharge and the logarithm of the measurement timing of the current. An inspection device equipped with the following features.

2. The current measuring unit continuously measures the current of the capacitor while it is being charged. The inspection apparatus according to claim 1, wherein the abnormality detection unit detects an abnormality in the capacitor based on a regression line relating to charging characteristics derived from the logarithm of the measured value of the current during the determination time range during charging and the logarithm of the timing of the current measurement.

3. The inspection apparatus according to claim 1 or 2, wherein the abnormality detection unit detects an abnormality in the capacitor based on the degree of agreement between the logarithm of the measured current and the logarithm of the measurement timing with respect to the regression line.

4. The inspection apparatus according to claim 1 or 2, wherein the abnormality detection unit detects an abnormality in the capacitor based on the logarithmic relationship of the measured current to at least one of the upper and lower limits of the current tolerance range determined with respect to the regression line over the judgment time range.

5. The abnormality detection unit, An abnormality in the capacitor is detected based on a first regression line derived from the logarithm of the measured current values ​​during the first determination time range during the discharge and the logarithm of the measurement timing of the current. The inspection device according to claim 1 or 2, which detects an abnormality in the capacitor based on a second regression line derived from the logarithm of the measured value of the current in the second determination time range during the discharge and the logarithm of the measurement timing of the current.

6. After the charging unit applies a voltage to the capacitor with a first polarity to perform first polarity charging, the discharging unit performs first polarity discharge of the capacitor. After the charging unit applies a voltage to the capacitor with a second polarity to perform second polarity charging, the discharging unit performs second polarity discharge of the capacitor. The current measuring unit is, The first polarity discharge current, which is the current of the capacitor during the first polarity discharge, is measured. The second polarity discharge current, which is the current of the capacitor during the second polarity discharge, is measured. The abnormality detection unit, An abnormality in the capacitor is detected based on a first polarity regression line derived from the logarithm of the measured value of the first polarity discharge current during the first determination time range in the first polarity discharge and the logarithm of the measurement timing of the first polarity discharge current. The inspection device according to claim 1 or 2, which detects an abnormality in the capacitor based on a second polarity regression line derived from the logarithm of the measured value of the second polarity discharge current in a second determination time range during the second polarity discharge and the logarithm of the measurement timing of the second polarity discharge current.

7. The process of charging the capacitor, The process of discharging the capacitor, A step of continuously measuring the current of the capacitor during discharge, A step of detecting an abnormality in the capacitor based on a regression line derived from the logarithm of the measured current values ​​and the logarithm of the measurement timing of the current during the determination time range during discharge, Testing methods including those mentioned.

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