Capacitor measuring device and capacitor measuring method

Abstract

This capacitor measuring device includes a supporting platform, a load application unit, and a signal processing unit. The supporting platform is for placing a wiring board having a multilayer ceramic capacitor mounted thereon. The load application unit presses the wiring board placed on the supporting platform to apply a load to the wiring board. The signal processing unit detects the occurrence timing of a crack generated in the multilayer ceramic capacitor due to the pressing force applied to the wiring board, on the basis of an abrupt change in an electrical characteristic including either a current that flows as a result of the occurrence of the crack generated in the multilayer ceramic capacitor due to the pressing force, or a voltage having a correspondence relationship with the current flowing through the multilayer ceramic capacitor. The load application unit increases the amount by which the wiring board is pressed by a predetermined amount of increase. The signal processing unit detects the occurrence timing of the crack on the basis of an abrupt change in the electrical characteristic with respect to the increase in the pressing amount, as the change in the electrical characteristic.

Description

Capacitor measuring device and capacitor measuring method

[0001] The present disclosure relates to a capacitor measurement device and a capacitor measurement method.

[0002] Multilayer ceramic capacitors are used in many electronic devices. When mechanical stress is applied to a printed wiring board on which a multilayer ceramic capacitor is mounted, cracks may occur inside the multilayer ceramic capacitor. To find such internal cracks, for example, Patent Document 1 proposes a method of directly observing the inside of a multilayer ceramic capacitor with a microscope and a method of detecting cracks based on the results of measuring the electrostatic capacitance.

[0003] Japanese Patent Application Publication No. 7-161570

[0004] Cracks that occur inside multilayer ceramic capacitors reduce performance related to the capacitor's reliability, such as humidity load resistance and thermal cycle performance. Therefore, there is a need to accurately detect cracks that occur inside capacitors.

[0005] In order to solve the above-mentioned problems, the present disclosure provides a capacitor measuring device that accurately detects cracks that occur in a multilayer ceramic capacitor.

[0006] The capacitor measuring device according to the present disclosure includes a support base, a load application unit, and a signal processing unit. The support base is for placing a wiring board on which a multilayer ceramic capacitor is mounted. The load application unit applies a load to the wiring board by pressing the wiring board placed on the support base. The signal processing unit detects the timing of occurrence of a crack in the multilayer ceramic capacitor due to the pressing of the wiring board based on a current flowing due to the occurrence of a crack in the multilayer ceramic capacitor due to the pressing, or a sudden change in electrical characteristics including a voltage corresponding to the current flowing in the multilayer ceramic capacitor. The load application unit increases the pressing amount against the wiring board by a predetermined increment. The signal processing unit detects the timing of occurrence of the crack based on the sudden change in the electrical characteristics in response to an increase in the pressing amount.

[0007] According to the present disclosure, a capacitor measuring device is provided that accurately detects cracks that occur in a multilayer ceramic capacitor.

[0008] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0009] 1 is a diagram schematically illustrating the configuration of a capacitor measuring device according to a first embodiment; FIG. 2 is a block diagram illustrating the configuration of a capacitor measuring device; FIG. 3 is a top view illustrating the configuration of a wiring board on which a multilayer ceramic capacitor is mounted; FIG. 4 is a perspective view illustrating the configuration of a multilayer ceramic capacitor; FIG. 5 is a cross-sectional view illustrating the configuration of a multilayer ceramic capacitor; FIG. 6 is a flowchart illustrating a method for measuring a capacitor according to the first embodiment; FIG. 7 is a diagram schematically illustrating a state in which a load application unit is pressing a wiring board; FIG. 8 is a diagram illustrating the amount of pressing into the wiring board and the current flowing through the multilayer ceramic capacitor over time; FIG. 9 is a diagram illustrating the amount of pressing into the wiring board and the current flowing through the multilayer ceramic capacitor over time; FIG. 10 is a diagram illustrating the amount of pressing into the wiring board and the voltage generated in the multilayer ceramic capacitor over time; FIG. 11 is a diagram illustrating the amount of pressing into the wiring board and the voltage generated in the multilayer ceramic capacitor over time; FIG. 12 is a diagram illustrating the amount of pressing into the wiring board and the voltage generated in the multilayer ceramic capacitor over time;

[0010] <First Embodiment> Fig. 1 is a diagram schematically illustrating the configuration of a capacitor measuring device 101 in accordance with a first embodiment. Fig. 2 is a block diagram illustrating the configuration of the capacitor measuring device 101. The measuring device 101 is a device for detecting cracks occurring inside a multilayer ceramic capacitor 10. The measuring device 101 includes a support base 20, a DC power supply 30, a detection unit 40, a load application unit 50, and a signal processing unit 60.

[0011] The support base 20 is provided so that a wiring board 70 on which a multilayer ceramic capacitor 10 to be measured is mounted can be placed. The wiring board 70 includes a first main surface 70A on which the multilayer ceramic capacitor 10 is mounted and a second main surface 70B opposite the first main surface 70A. The wiring board 70 is, for example, a printed wiring board. FIG. 3 is a top view showing the configuration of the wiring board 70 on which the multilayer ceramic capacitor 10 is mounted. The wiring board 70 includes first copper wiring 71 and second copper wiring 72 on the first main surface 70A. The multilayer ceramic capacitor 10 includes a first external electrode 11A and a second external electrode 12A. The first external electrode 11A and the second external electrode 12A are provided on both ends of the multilayer ceramic capacitor 10 and form its outer surfaces. The first external electrode 11A and the second external electrode 12A of the multilayer ceramic capacitor 10 are respectively joined to the first copper wiring 71 and the second copper wiring 72 of the wiring board 70 by a joining material such as solder.

[0012] FIG. 4 is a perspective view showing the configuration of the multilayer ceramic capacitor 10. FIG. 5 is a cross-sectional view showing the configuration of the multilayer ceramic capacitor 10. FIG. 5 shows a cross section taken along the plane WXYZ shown in FIG. 4. The multilayer ceramic capacitor 10 includes a plurality of first internal electrodes 11B, a plurality of second internal electrodes 12B, and a ceramic body 13 therein. The first internal electrode 11B is structurally and electrically connected to the first external electrode 11A. The second internal electrode 12B is structurally and electrically connected to the second external electrode 12A. The first internal electrodes 11B and the second internal electrodes 12B are alternately arranged so as to face each other inside the multilayer ceramic capacitor 10. The ceramic body 13 fills the space between the first internal electrodes 11B and the second internal electrodes 12B. A parallel capacitance is formed between the plurality of first internal electrodes 11B and the plurality of second external electrodes 12A.

[0013] The DC power supply 30 is connected to the first external electrode 11A and the second external electrode 12A of the multilayer ceramic capacitor 10. The DC power supply 30 applies a voltage between the first external electrode 11A and the second external electrode 12A.

[0014] The detection unit 40 is provided on the wiring connecting the multilayer ceramic capacitor 10 and the DC power supply 30. The detection unit 40 in the first embodiment detects the current output from the multilayer ceramic capacitor 10 as an electrical characteristic of the multilayer ceramic capacitor 10. The detection unit 40 includes, for example, a clamp-type current probe.

[0015] The load application unit 50 applies a load to the wiring board 70 by pressing the wiring board 70 placed on the support base 20. The load application unit 50 includes a load application device main body 51 and a pusher 52. The pusher 52 corresponds to the pressing unit. The pusher 52 is connected to the load application device main body 51 and presses the second main surface 70B of the wiring board 70 placed on the support base 20. The load application unit 50 controls the pusher 52 so that the pusher 52 presses the second main surface 70B of the wiring board 70 until the amount of pressing against the wiring board 70 reaches a predetermined value. The load application unit 50 controls the pusher 52, for example, so that the amount of pressing against the wiring board 70 increases by a predetermined increment. For example, the load application unit 50 controls the pusher 52 so that the amount of pressing against the wiring board 70 increases at a constant rate. The amount of pressing corresponds to, for example, the pressing dimension. The load application unit 50 then controls the plunger 52 so that the plunger 52 stops.

[0016] The signal processing unit 60 detects the timing of occurrence of a crack in the multilayer ceramic capacitor 10 due to pressure applied to the wiring board 70, based on a change in the electrical characteristics of the multilayer ceramic capacitor 10 caused by the pressure. In the first embodiment, the electrical characteristics correspond to the current flowing through the multilayer ceramic capacitor 10. The signal processing unit 60 includes an amplifier 61 and a measuring unit 62. The functions of the signal processing unit 60 described above are realized by the amplifier 61 and the measuring unit 62.

[0017] The amplifier 61 is electrically connected to the detection unit 40 and the measurement unit 62. The amplifier 61 amplifies the current detected by the detection unit 40. Although the amplifier 61 is not an essential component, when the current flowing through the multilayer ceramic capacitor 10 is weak, the current is amplified by the amplifier 61. Therefore, the measurement unit 62 can measure even weak changes in the current.

[0018] The measuring unit 62 is electrically connected to the amplifier 61 and the load applying unit 50. The measuring unit 62 synchronously records the amount of pressing against the wiring board 70 and the current value detected by the detecting unit 40. When the multilayer ceramic capacitor 10 is broken by pressing, a current flows suddenly through the multilayer ceramic capacitor 10. The measuring unit 62 detects the timing of crack occurrence based on a sudden change in the current in response to an increase in the amount of pressing, as a change in the electrical characteristics. The measuring unit 62 may record the start time and end time of pressing by the load applying unit 50.

[0019] 6 is a flowchart showing a method for measuring a capacitor according to embodiment 1. This method is a method for accurately detecting cracks occurring in multilayer ceramic capacitor 10.

[0020] In step S1, the wiring board 70 on which the multilayer ceramic capacitor 10 is mounted is placed on the support base 20. As shown in FIG. 1 , the wiring board 70 is placed so that the first main surface 70A on which the multilayer ceramic capacitor 10 is mounted faces downward.

[0021] In step S2, the DC power supply 30 applies a voltage to the first external electrode 11A and the second external electrode 12A of the multilayer ceramic capacitor 10. Prior to this voltage application, various preparations are made. For example, the first copper wiring 71 and the second copper wiring 72 of the wiring board 70 are connected to the DC power supply 30 via wiring such as a cable. The detection unit 40 is disposed on the wiring connecting the multilayer ceramic capacitor 10 and the DC power supply 30. The gain of the amplifier 61 is adjusted to, for example, 10 dB or more and 1000 dB or less. In this state, a voltage is applied to the multilayer ceramic capacitor 10.

[0022] In step S3, the load application unit 50 presses the wiring board 70 placed on the support base 20 to apply a load to the wiring board 70. At this time, the presser 52 presses the second main surface 70B of the wiring board 70 opposite the first main surface 70A on which the multilayer ceramic capacitor 10 is mounted. The presser 52 presses from above to below a portion of the second main surface 70B that corresponds directly above the multilayer ceramic capacitor 10. The presser 52 increases the amount of pressing against the wiring board 70 by a predetermined increment.

[0023] 7 is a diagram showing a state in which load application unit 50 is pressing wiring board 70. Wiring board 70 is bent and deformed into a downwardly convex shape. Presser 52 presses wiring board 70 until the pressing force against wiring board 70 reaches a predetermined value.

[0024] In step S4, the detection unit 40 detects the electrical characteristics of the multilayer ceramic capacitor 10 on the wiring connecting the multilayer ceramic capacitor 10 and the DC power supply 30. The detection unit 40 of the first embodiment detects the current output from the multilayer ceramic capacitor 10 as the electrical characteristic.

[0025] In step S5, the signal processing unit 60 detects the timing of occurrence of a crack in the multilayer ceramic capacitor 10 due to the pressure applied to the wiring board 70, based on a change in the electrical characteristic of the multilayer ceramic capacitor 10 caused by the pressure. As described above, the electrical characteristic in the first embodiment is the current output from the multilayer ceramic capacitor 10. If the current is weak, the current is amplified by the amplifier 61. The measuring unit 62 synchronously records the amount of pressing against the wiring board 70 and the current value in the multilayer ceramic capacitor 10. The measuring unit 62 records the amount of pressing against the wiring board 70 and the current value from when the presser 52 starts pressing against the wiring board 70 until the amount of pressing reaches a predetermined value.

[0026] 8 and 9 are diagrams showing the amount of pressing into the wiring board 70 and the current flowing through the multilayer ceramic capacitor 10 over time. As the presser 52 presses against the wiring board 70, the wiring board 70 gradually bends. A strain corresponding to the amount of pressing is then applied to the multilayer ceramic capacitor 10. If the internal stress caused by the strain exceeds the limit strength of the multilayer ceramic capacitor 10, a crack will occur inside the multilayer ceramic capacitor 10.

[0027] As shown in FIG. 8, a steep increase in current is measured at time t1. This steep change in current corresponds to the timing when a crack occurs inside the multilayer ceramic capacitor 10. Therefore, the measurement unit 62 detects time t1 as the timing when a crack occurs. The steep increase in current occurs, for example, at a time of approximately 0.1 to 100 msec. On the other hand, if a crack does not occur, no steep change in current is measured, as shown in FIG. 9. In this way, the measurement unit 62 detects the timing when a crack occurs based on the steep change in current in response to an increase in the amount of depression.

[0028] To summarize the above, the capacitor measuring device 101 in the first embodiment includes a support base 20, a load application unit 50, and a signal processing unit 60. The support base 20 is used to place a wiring board 70 on which a multilayer ceramic capacitor 10 is mounted. The load application unit 50 applies a load to the wiring board 70 by pressing the wiring board 70 placed on the support base 20. The signal processing unit 60 detects the timing of occurrence of a crack that occurs in the multilayer ceramic capacitor 10 due to the pressure on the wiring board 70, based on a change in the electrical characteristic that occurs in the multilayer ceramic capacitor 10 due to the pressure. The electrical characteristic is the current flowing through the multilayer ceramic capacitor 10.

[0029] The capacitor measuring device 101 having such a configuration detects cracks occurring in the multilayer ceramic capacitor 10 with high accuracy.

[0030] In a crack detection method in which the inside of multilayer ceramic capacitor 10 is directly observed with a microscope, many steps and time are required to inspect a single capacitor, such as polishing the capacitor, cleaning the polished surface, and setting the capacitor under the microscope. On the other hand, the measurement method of embodiment 1 does not require steps such as polishing multilayer ceramic capacitor 10. Measuring device 101 makes it possible to detect cracks in a short time without directly observing the inside of the capacitor.

[0031] In a method for detecting cracks based on capacitance measurement results, minute cracks that cause the internal electrodes to remain in close contact without separating do not affect the capacitance or dissipation factor. Therefore, minute cracks are not detected. On the other hand, in the measurement method of embodiment 1, measurements are performed in a state in which the crack has expanded due to deformation caused by strain in the multilayer ceramic capacitor 10. Therefore, the measuring device 101 of embodiment 1 detects changes in current caused by the minute crack, even if the crack is minute. The measuring device 101 enables accurate detection of cracks in the multilayer ceramic capacitor 10.

[0032] When the multilayer ceramic capacitor 10 has a ferroelectric material as the ceramic body 13, a phenomenon called DC (direct current) bias characteristic occurs. The DC bias phenomenon occurs when a DC voltage is applied to a capacitor, and the capacitance decreases depending on the voltage and the duration of application of that voltage. It is difficult to determine whether a minute change in capacitance occurring in a capacitor is due to a crack or a DC bias characteristic. The measuring device 101 of the first embodiment detects not the change in capacitance itself caused by a crack, but the sudden change in discharge current resulting from that change in capacitance. Therefore, the measuring device 101 is capable of detecting the occurrence of a crack with high accuracy.

[0033] The sudden increase in current at the time when a crack occurs is thought to be caused by various factors. As one example, the sudden increase in current is thought to be caused by the piezoelectric phenomenon of the multilayer ceramic capacitor 10, which is made of a material having an electrostrictive effect. In the multilayer ceramic capacitor 10, a voltage proportional to the product of the stress generated within the multilayer ceramic capacitor 10 and the piezoelectric coefficient of the multilayer ceramic capacitor 10 is generated between the two external electrodes of the multilayer ceramic capacitor 10. When the pusher 52 presses the wiring board 70, stress is generated within the multilayer ceramic capacitor 10. However, at the moment when a crack occurs, the internal stress changes abruptly. Therefore, the voltage generated between the two external electrodes of the multilayer ceramic capacitor 10 due to the piezoelectric effect also changes abruptly. As a result, the current output from the multilayer ceramic capacitor 10 also changes at abrupt speed.

[0034] As another example, the sudden increase in current is thought to be caused by a change in capacitance due to the internal electrodes being electrically disconnected by a crack. When the internal electrodes are electrically disconnected by a crack, the capacitance formed in parallel inside the capacitor is instantly reduced due to the occurrence of the crack. Therefore, a sudden change in discharge current occurs due to the decrease in capacitance. As a result, the current output from the multilayer ceramic capacitor 10 also changes at a rapid rate.

[0035] The factors that cause the sudden change in electrical characteristics when a crack occurs are not limited to those described above. Even if the cause of the change is other factors, the signal processing unit 60 detects the timing of the crack occurrence based on the change in electrical characteristics caused by the pressure. Therefore, the capacitor measuring device 101 can accurately detect cracks that occur in the multilayer ceramic capacitor 10.

[0036] Second Embodiment In a second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0037] FIG. 10 is a diagram schematically illustrating the configuration of a capacitor measuring device 102 according to the second embodiment.

[0038] The detection unit 40 of the second embodiment includes a resistor 41. This resistor 41 is called a shunt resistor. The resistor 41 is connected in series to a wiring through which a current is output from the multilayer ceramic capacitor 10. The voltage across the resistor 41 corresponds to the product of the current flowing through the resistor 41 and the resistance value of the resistor 41. In other words, the voltage across the resistor 41 corresponds to the product of the current flowing through the multilayer ceramic capacitor 10 and the resistance value of the resistor 41.

[0039] As in the first embodiment, the signal processing unit 60 detects the timing of occurrence of a crack in the multilayer ceramic capacitor 10 due to pressure applied to the wiring board 70, based on a change in the electrical characteristics of the multilayer ceramic capacitor 10 caused by the pressure. The electrical characteristics in the second embodiment are voltages detected by the detection unit 40, and the voltages correspond to the currents flowing through the multilayer ceramic capacitor 10. If the voltage is weak, the voltage is amplified by the amplifier 61. The measurement unit 62 synchronously records the amount of pressure applied to the wiring board 70 and the voltage values ​​detected by the detection unit 40.

[0040] When the multilayer ceramic capacitor 10 is broken by the pressure applied by the plunger 52, a current flows suddenly through the multilayer ceramic capacitor 10. Therefore, the voltage detected by the detection unit 40 also changes suddenly.

[0041] 11 and 12 are diagrams showing the amount of pressing into the wiring board 70 and the voltage generated in the multilayer ceramic capacitor 10 over time.

[0042] As shown in Fig. 11, a steep increase in voltage is measured at time t2. This steep change in voltage corresponds to the timing when a crack occurs inside the multilayer ceramic capacitor 10. Therefore, the measuring unit 62 detects time t2 as the timing when a crack occurs. On the other hand, if no crack occurs, no steep change in voltage is measured, as shown in Fig. 12. In this way, the measuring unit 62 detects the timing when a crack occurs based on the steep change in voltage in response to an increase in the amount of depression.

[0043] As described above, the signal processing unit 60 of the second embodiment detects the timing of occurrence of a crack caused by pressure applied to the wiring board 70 based on the change in the electrical characteristic of the multilayer ceramic capacitor 10 caused by the pressure. In the second embodiment, the electrical characteristic is a voltage that has a corresponding relationship with the current flowing through the multilayer ceramic capacitor 10.

[0044] Third Embodiment In a third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0045] Fig. 13 is a diagram schematically showing the configuration of a capacitor measuring device 103 in embodiment 3. Fig. 14 is a block diagram showing the configuration of the capacitor measuring device 103.

[0046] The signal processing unit 60 includes a frequency filter 63 in addition to the configuration of the first embodiment. The frequency filter 63 removes low-frequency components, such as DC components, contained in changes in current. The frequency filter 63 in the third embodiment is provided between the amplifier 61 and the measurement unit 62. The cutoff frequency of the frequency filter 63 is set, for example, to a value not less than 0.1 Hz and not more than 100 kHz. The cutoff frequency of the frequency filter 63 is adjusted, for example, based on what is generally called the cutoff frequency, a frequency below which the gain of the circuit drops by 3 dB from its normal value.

[0047] The measuring unit 62 records only the change in the current from which the low frequency components have been removed by the frequency filter 63 .

[0048] As in the first embodiment, the pusher 52 presses the second main surface 70B opposite to the first main surface 70A of the wiring board 70 on which the multilayer ceramic capacitor 10 is mounted. The pusher 52 presses the second main surface 70B from above to below at a location directly above the multilayer ceramic capacitor 10. The wiring board 70 bends and deforms into a downwardly convex shape. When a crack occurs due to an increase in the amount of pressing, a current suddenly flows through the multilayer ceramic capacitor 10.

[0049] 15 and 16 are diagrams showing the amount of pressing into the wiring board 70 and the current flowing through the multilayer ceramic capacitor 10 over time.

[0050] As shown in Figure 15, a steep increase in current is measured at time t3. This steep change in current corresponds to the timing when a crack occurs inside the multilayer ceramic capacitor 10. Therefore, the measuring unit 62 detects time t3 as the timing when a crack occurs. On the other hand, if no crack occurs, no steep change in voltage is measured, as shown in Figure 16. In these results, changes in current other than time t3 when the crack occurs are removed by the frequency filter 63.

[0051] In this way, the measuring unit 62 of the third embodiment measures and records only the abrupt change in current when a crack occurs inside the multilayer ceramic capacitor 10. The signal processing unit 60 detects the timing of the crack occurrence based on the abrupt change in current. Since low-frequency components such as DC components are removed, the detection accuracy is improved.

[0052] Fourth Embodiment In a fourth embodiment, the same components as those in any of the first to third embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0053] The measuring unit 62 synchronously records the amount of indentation applied to the wiring board 70 and the current output from the multilayer ceramic capacitor 10. The measuring unit 62 of the fourth embodiment converts the amount of indentation into the amount of strain applied to the multilayer ceramic capacitor 10. This allows the amount of strain at the time of crack generation to be calculated.

[0054] For example, by performing measurements multiple times using this embodiment, the variation in the amount of strain when cracks occur can be measured. This allows the distribution of the amount of strain when cracks occur to be obtained. Figure 17 is a diagram showing the distribution of the amount of strain when cracks occur. The crack resistance against strain is measured as the actual distribution.

[0055] Although the present disclosure has been described in detail, the above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0056] In the present disclosure, the embodiments can be freely combined, and the embodiments can be modified or omitted as appropriate.

[0057] Various aspects of the present disclosure are summarized below as appendices.

[0058] (Supplementary Note 1) A capacitor measuring device comprising: a support base for placing a wiring board on which a multilayer ceramic capacitor is mounted; a load application unit that applies a load to the wiring board by pressing the wiring board placed on the support base; and a signal processing unit that detects the timing of occurrence of a crack that occurs in the multilayer ceramic capacitor due to the pressing against the wiring board, based on a current that flows due to the occurrence of a crack that occurs in the multilayer ceramic capacitor due to the pressing, or a sudden change in an electrical characteristic including a voltage that has a correspondence relationship with the current that flows in the multilayer ceramic capacitor, wherein the load application unit increases the amount of pressing against the wiring board by a predetermined increment, and the signal processing unit detects the timing of occurrence of the crack based on a sudden change in the electrical characteristic with respect to the increase in the amount of pressing, as the change in the electrical characteristic.

[0059] (Supplementary Note 2) The capacitor measuring device according to Supplementary Note 1 further comprises: a DC power supply that applies a voltage to external electrodes provided on the multilayer ceramic capacitor; and a detection unit that is provided on wiring connecting the multilayer ceramic capacitor and the DC power supply and detects the electrical characteristics of the multilayer ceramic capacitor, wherein the signal processing unit includes: an amplifier that amplifies the electrical characteristics detected by the detection unit; and a measurement unit that detects the occurrence timing of the crack based on the change in the electrical characteristics amplified by the amplifier.

[0060] (Supplementary Note 3) The capacitor measuring device according to Supplementary Note 1 or Supplementary Note 2, wherein the wiring board includes a first main surface on which the multilayer ceramic capacitor is mounted and a second main surface opposite to the first main surface, the load application unit includes a pressing unit that presses the second main surface of the wiring board, and the signal processing unit synchronously records the amount of pressing against the wiring board and the value of the electrical characteristic.

[0061] (Supplementary Note 4) The capacitor measuring device according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the signal processing unit further includes a frequency filter that removes low-frequency components in the change in the electrical characteristic.

[0062] (Appendix 5) A method for measuring a capacitor, comprising: a step of placing a wiring board on a support base, on which a multilayer ceramic capacitor is mounted; a step of pressing the wiring board placed on the support base to apply a load to the wiring board; and a step of detecting the timing of occurrence of a crack in the multilayer ceramic capacitor due to the pressing of the wiring board, based on a current flowing due to the occurrence of a crack in the multilayer ceramic capacitor due to the pressing, or a sudden change in an electrical characteristic including a voltage having a correspondence relationship with the current flowing in the multilayer ceramic capacitor, wherein the step of applying the load to the wiring board increases an amount of pressing on the wiring board by a predetermined increment, and the step of detecting the timing of occurrence of the crack detects the timing of occurrence of the crack based on a sudden change in the electrical characteristic with respect to the increase in the amount of pressing.

[0063] (Supplementary Note 6) The capacitor measurement method according to Supplementary Note 5, further comprising: a step of applying a voltage to external electrodes provided on the multilayer ceramic capacitor by a DC power supply; and a step of detecting the electrical characteristics of the multilayer ceramic capacitor on wiring connecting the multilayer ceramic capacitor and the DC power supply, wherein the step of detecting the timing of occurrence of the crack includes a step of amplifying the electrical characteristics by an amplifier; and a step of detecting the timing of occurrence of the crack based on the change in the electrical characteristics amplified by the amplifier.

[0064] (Supplementary Note 7) The method for measuring a capacitor according to Supplementary Note 5 or Supplementary Note 6, wherein the wiring board includes a first main surface on which the multilayer ceramic capacitor is mounted and a second main surface opposite to the first main surface, the step of pressing the wiring board includes pressing the second main surface of the wiring board, and the step of detecting the timing of occurrence of the crack includes synchronously recording the amount of pressing against the wiring board and the value of the electrical characteristic.

[0065] (Supplementary Note 8) The method for measuring a capacitor according to any one of Supplementary Note 5 to Supplementary Note 7, further comprising the step of removing low-frequency components in the change in the electrical characteristic by a frequency filter.

[0066] 10 Multilayer ceramic capacitor, 11A First external electrode, 11B First internal electrode, 12A Second external electrode, 12B Second internal electrode, 13 Ceramic body, 20 Support base, 30 DC power supply, 40 Detection unit, 41 Resistor, 50 Load application unit, 51 Load application device main body, 52 Pusher, 60 Signal processing unit, 61 Amplifier, 62 Measurement unit, 63 Frequency filter, 70 Wiring board, 70A First main surface, 70B Second main surface, 71 First copper wiring, 72 Second copper wiring, 101 to 103 Measurement device.

Claims

1. a support base for placing a wiring board on which the multilayer ceramic capacitor is mounted; a load applying unit that applies a load to the wiring board by pressing the wiring board placed on the support base; a signal processing unit that detects the timing of occurrence of a crack in the multilayer ceramic capacitor due to pressure applied to the wiring board based on a discharge current generated by a change in capacitance caused by the crack in the multilayer ceramic capacitor due to the pressure, or a sudden change in an electrical characteristic including a voltage having a corresponding relationship with the discharge current flowing through the multilayer ceramic capacitor, the load applying unit increases a pressing amount against the wiring board by a predetermined increment; The signal processing unit detects the timing of occurrence of the crack based on a steep change in the electrical characteristic in response to an increase in the amount of pressing, as the change in the electrical characteristic.

2. a DC power supply that applies a voltage to external electrodes provided on the multilayer ceramic capacitor; a detection unit that is provided on a wiring that connects the multilayer ceramic capacitor and the DC power supply and that detects the electrical characteristics of the multilayer ceramic capacitor, The signal processing unit an amplifier that amplifies the electrical characteristic detected by the detection unit; 2. The capacitor measuring device according to claim 1, further comprising: a measuring unit that detects the occurrence timing of the crack based on the change in the electrical characteristic amplified by the amplifier.

3. the wiring board includes a first main surface on which the multilayer ceramic capacitor is mounted and a second main surface opposite to the first main surface, the load application portion includes a pressing portion that presses the second main surface of the wiring board, 2. The capacitor measuring device according to claim 1, wherein the signal processing unit synchronously records the amount of pressing of the wiring board and the value of the electrical characteristic.

4. The capacitor measuring device according to claim 1 , wherein the signal processing unit further comprises a frequency filter that removes low-frequency components in the change in the electrical characteristic.

5. a step of placing the wiring board on which the multilayer ceramic capacitor is mounted on a support; a step of applying a load to the wiring board by pressing the wiring board placed on the support base; detecting timing of occurrence of cracks in the multilayer ceramic capacitor due to pressure applied to the wiring board based on a discharge current generated by a change in capacitance caused by the cracks in the multilayer ceramic capacitor due to the pressure, or a sudden change in electrical characteristics including a voltage having a corresponding relationship with the discharge current flowing through the multilayer ceramic capacitor, The step of applying the load to the wiring board includes increasing a pressing amount to the wiring board by a predetermined increment; A capacitor measurement method in which the step of detecting the timing of the crack occurrence detects the timing of the crack occurrence based on a steep change in the electrical characteristic in response to an increase in the amount of pressing, as the change in the electrical characteristic.

6. applying a voltage to external electrodes provided on the multilayer ceramic capacitor using a DC power supply; detecting the electrical characteristics of the multilayer ceramic capacitor on a wiring connecting the multilayer ceramic capacitor and the DC power supply, The step of detecting the occurrence timing of the crack includes: amplifying the electrical characteristic with an amplifier; 6. The method for measuring a capacitor according to claim 5, further comprising: detecting the occurrence timing of the crack based on the change in the electrical characteristic amplified by the amplifier.

7. the wiring board includes a first main surface on which the multilayer ceramic capacitor is mounted and a second main surface opposite to the first main surface, the step of pressing the wiring board includes pressing the second main surface of the wiring board; 6. The method for measuring a capacitor according to claim 5, wherein the step of detecting the timing of occurrence of the crack includes recording the amount of pressing into the wiring board and the value of the electrical characteristic in synchronization with each other.

8. 6. The method of claim 5, further comprising the step of removing low frequency components in the change in the electrical characteristic by a frequency filter.