WO2022163532A1

WO2022163532A1 - Measuring apparatus and measuring method

Info

Publication number: WO2022163532A1
Application number: PCT/JP2022/002230
Authority: WO
Inventors: 大樹山上; 行成野津; 康暉上原
Original assignee: 三菱電機株式会社
Priority date: 2021-02-01
Filing date: 2022-01-21
Publication date: 2022-08-04
Also published as: JPWO2022163532A1; JP7479522B2; TWI830131B; TW202234042A

Abstract

A measuring apparatus (1) is provided with a support stand (203) for mounting a printed wiring board (102), a load application device (201) for applying a load to the printed wiring board (102) mounted on the support stand, a presser (202) for pressing the printed wiring board (102) by means of the load applied from the load application device (201), and an acoustic emission (AE) sensor (301) for detecting a change that occurs in a ceramic electronic component (101) when the ceramic electronic component (101) is broken as a result of the printed wiring board (102) being pressed by the presser (202). The acoustic emission (AE) sensor (301) is configured so as to be attached to the surface of the printed wiring board (102) on which the ceramic electronic component (101) is packaged.

Description

Measuring device and method

The present disclosure relates to a measuring device and a measuring method.

In recent years, with the spread of mobile phones and smartphones and the digitization of automobile parts, the demand for ceramic electronic parts such as multilayer ceramic capacitors is on the rise in multiple industrial fields. Ceramic electronic components are indispensable for the stable operation of electronic equipment, so a stable supply is required.

By the way, ceramic electronic components have different internal structures and materials depending on the manufacturer or product type. Therefore, the resistance to bending of the printed board differs depending on the ceramic electronic component. Printed board bending resistance is the resistance of a ceramic electronic component to mechanical stress applied to a printed wiring board on which the ceramic electronic component is mounted. When the used ceramic electronic parts are replaced with other manufacturers or other types, printed wiring with solder-mounted ceramic electronic parts must be understood not only for the electrical characteristics of the ceramic electronic parts but also for the bending resistance of the printed board. Mechanical stress on the plate can cause cracks in ceramic electronic components. Cracks may develop into problems such as short circuits or changes in electrical characteristics. Examples of mechanical stress that occurs at the manufacturing site include mechanical stress that occurs when a printed wiring board is divided, when wiring is inserted into or removed from a connector mounted on the printed wiring board, and the like.

In order to use ceramic electronic components so that cracks do not occur in the ceramic electronic components, the printed board bending resistance of the ceramic electronic components to be used must be measured in advance, and the upper limit of the mechanical stress generated at the manufacturing site can be determined from the measurement results. It is important that the value is set and that the printed board bending resistance and mechanical stress are properly controlled.

Conventionally, evaluation of printed board bending resistance is performed by the method specified in JISC5101-22. In this method, failure is determined from changes in the electrical characteristics of the ceramic electronic component due to the bending of the printed wiring board. However, this method cannot detect microcracks whose electrical characteristics do not change. When a microcrack occurs, there is no noticeable abnormality in the appearance, and the electrical characteristics are often normal. However, microcracks generated inside degrade moisture resistance, causing migration, delamination, and the like, which may cause failures after many years have passed.

A detection method using the acoustic emission (AE) method has been proposed as a method for detecting microcracks. The acoustic emission (AE) method is described, for example, in Japanese Patent Laying-Open No. 2010-237197 (Patent Document 1). The measuring apparatus described in this publication includes a load applying device for applying a load to an object to be measured, a presser connected to the load applying device, and a support base for placing the object to be measured. ing. The device described in this publication has the function of measuring the load when the ceramic electronic component is destroyed from the reaction of an acoustic emission (AE) sensor built into the support base. However, this publication does not disclose measuring the breaking strength of a ceramic electronic component mounted on a printed wiring board.

JP 2010-237197 A

The above publication does not disclose evaluation of bending resistance of printed boards. Furthermore, it does not disclose how to evaluate the bending resistance of printed boards with high accuracy.

The present disclosure has been made in view of the above problems, and its purpose is to provide a measuring apparatus and a measuring method capable of evaluating the bending resistance of a printed board with high accuracy.

The measuring device of the present disclosure is a measuring device for measuring the printed board bending resistance of ceramic electronic components mounted on a printed wiring board. The measuring device is connected to a support base for mounting the printed wiring board, a load application device for applying a load to the printed wiring board mounted on the support base, and the load application device, A pusher for pressing the printed wiring board by the load applied from the load applying device, and the change that occurred in the ceramic electronic component when the printed wiring board was pressed by the pusher and the ceramic electronic component was destroyed. with an acoustic emission sensor for detection. Acoustic emission sensors are configured to be mounted on the surface of a printed wiring board on which ceramic electronic components are mounted.

According to the measuring device of the present disclosure, the acoustic emission sensor is configured to be attached to the surface of the printed wiring board on which ceramic electronic components are mounted. Therefore, the bending resistance of the printed board can be evaluated with high accuracy.

1 is a front view schematically showing the configuration of a measuring device according to Embodiment 1; FIG. 1 is a block diagram showing the configuration of a measuring device according to Embodiment 1; FIG. FIG. 2 is a bottom view schematically showing the configuration of the object to be measured according to Embodiment 1; 4 is a flow chart showing the operation of the measuring device according to Embodiment 1. FIG. FIG. 4 is a partial front view schematically showing how the pusher of the measuring device according to Embodiment 1 pushes the object to be measured. FIG. 4 is a bottom view of the object to be measured, schematically showing the contact position of the pusher on the object to be measured. FIG. 3 is a front view schematically showing the configuration of a modification of the measuring device according to Embodiment 1; 4 is a flow chart showing a measuring method according to Embodiment 1. FIG. 2 is a partial front view schematically showing the configuration of a measuring device of Comparative Example 1. FIG. FIG. 11 is a partial front view schematically showing the configuration of a measuring device of Comparative Example 2; 1 is a partial front view schematically showing the configuration of a measuring device according to Embodiment 1; FIG. FIG. 7 is a front view schematically showing the configuration of a measuring device according to Embodiment 2; 2 is a block diagram showing the configuration of a measuring device according to Embodiment 2; FIG. FIG. 10 is a partial front view schematically showing how the pusher of the measuring device according to Embodiment 2 pushes the object to be measured; FIG. 11 is a front view schematically showing the configuration of a measuring device according to Embodiment 3; FIG. 10 is a block diagram showing the configuration of a measuring device according to Embodiment 3; FIG. 11 is a perspective view schematically showing the structure of a fixing jig of a measuring device according to Embodiment 3; FIG. 11 is a perspective view schematically showing a state in which an acoustic emission sensor is fixed to a printed wiring board using a fixing jig of a measuring device according to Embodiment 3; 10 is a graph showing distributions of cumulative failure rates and strain amounts of laminated ceramic capacitors measured according to Embodiment 3, using a 3-parameter Weibull distribution. 10 is a graph showing cumulative failure rate distributions of laminated ceramic capacitors measured according to Embodiment 3, and comparing characteristics between manufacturers using a 3-parameter Weibull distribution. FIG. 11 is a front view schematically showing the configuration of a measuring device according to Embodiment 4; FIG. 11 is a block diagram showing the configuration of a measuring device according to Embodiment 4; FIG. 11 is a perspective view schematically showing a state in which an acoustic emission sensor is fixed to a printed wiring board using a fixing jig of a measuring device according to Embodiment 4;

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the present disclosure is not limited to the following description, and can be modified as appropriate without departing from the gist of the present disclosure. Further, in the present specification and drawings, constituent elements having substantially the same functions are denoted by the same reference numerals, thereby omitting redundant description. In the drawings, figures showing the configuration of the device and the shapes of the members only show the schematic configuration and shape of the device and the members. The relative size and relative position of each member illustrated in each drawing do not necessarily accurately represent the actual size relationship and positional relationship between the members.

Embodiment 1.
FIG. 1 is a front view schematically showing the configuration of a measuring apparatus 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method according to Embodiment 1 is applied. FIG. 2 is a block diagram showing the configuration of a measuring apparatus 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method according to Embodiment 1 is applied.

As shown in FIGS. 1 and 2, the measuring device 1 according to Embodiment 1 is for measuring a measurement target 100. FIG. A measurement target 100 includes a ceramic electronic component 101 and a printed wiring board 102 . A measuring apparatus 1 is for measuring the printed board bending resistance of a ceramic electronic component 101 mounted on a printed wiring board 102 .

The measuring device 1 includes a load applying section 200 , a crack occurrence detecting section 300 , a crack occurrence signal processing section 400 , and a load applying device stop processing section 500 . The load application unit 200 is configured to mount the object 100 to be measured. The load application unit 200 includes a load application device 201 , a pusher 202 and a support base 203 . The crack occurrence detector 300 is configured to be fixed to the object to be measured. A crack occurrence detection unit 300 includes an acoustic emission (AE) sensor 301 and an adhesive 304 . The crack occurrence detection section 300 is configured to be electrically connected to the crack occurrence signal processing section 400 . The crack generation signal processing section 400 includes a voltage measuring device 403 . The crack occurrence signal processing section 400 is configured to be electrically connected to the load applying device stop processing section 500 . The load application device stop processing unit 500 includes an electronic component having a voltage conversion function such as a DCDC converter. The load applying device stop processing section 500 is configured to be electrically connected to the load applying section 200 .

FIG. 3 is a bottom view schematically showing the configuration of the measurement object 100 according to Embodiment 1. FIG. As shown in FIGS. 2 and 3, ceramic electronic component 101 is mounted on printed wiring board 102 . Specifically, ceramic electronic component 101 is solder-mounted to copper pads 102 A of printed wiring board 102 using solder 103 . Reflow is applied for solder mounting. Also, flux cleaning is performed after reflow. This removes the flux between the ceramic electronic component 101 and the printed wiring board 102 . The specifications of the printed wiring board 102 conform to, for example, JISC5101-1. As the printed wiring board 102, for example, a glass cloth-based epoxy resin printed wiring board copper-clad laminate having a thickness of 1.6 mm±0.2 mm or 0.8 mm±0.1 mm is used.

As shown in FIG. 1, the pusher 202 and the support base 203 are fixed to the load application device 201 with screws. The specifications of the pusher 202 and the support base 203 conform to, for example, JISC5101-22. The radius of curvature of the tip of the pusher 202 is set to 5 mm.

The support table 203 is for placing the printed wiring board 102 thereon. The load application device 201 is for applying a load to the printed wiring board 102 placed on the support base 203 . The pusher 202 is connected to the load applying device 201 . The presser 202 presses the printed wiring board 102 with the load applied from the load applying device 201 .

The acoustic emission (AE) sensor is for detecting changes occurring in the ceramic electronic component 101 when the printed wiring board 102 is pressed against the pusher 202 and the ceramic electronic component 101 is destroyed. Acoustic emission sensor (AE) 301 is configured to be attached to surface S1 of printed wiring board 102 on which ceramic electronic component 101 is mounted. In this embodiment, acoustic emission sensor (AE) 301 is directly attached to surface S1 of printed wiring board 102 on which ceramic electronic component 101 is mounted. In this embodiment, acoustic emission (AE) sensor 301 is fixed directly to copper pad 102A of printed wiring board 102 (see FIG. 11). In this embodiment, acoustic emission sensor (AE) 301 is fixed using adhesive 304 to printed wiring board 102 on which ceramic electronic component 101 is solder-mounted. Adhesive 304 is a thermoplastic adhesive such as ethylene vinyl acetate. At the time of adhesion, the acoustic emission (AE) sensor 301 and the printed wiring board 102 are heated to 80° C. by a hot plate or the like, and the adhesive 304 is applied and adhered. The application amount of the adhesive 304 is, for example, 0.05 ml or more and 0.50 ml or less.

As shown in FIG. 3, the installation position IP of the acoustic emission (AE) sensor 301 is installed on the printed wiring board 102 closer to the ceramic electronic component 101 than the contact position CP of the support base 203 . The contact position CP of the support base 203 functions as a fulcrum. Preferably, the installation position IP of the acoustic emission (AE) sensor 301 is installed near the ceramic electronic component 101 . It should be noted that the acoustic emission (AE) sensor may be any size as long as it can be mounted on the printed wiring board 102 .

As shown in FIG. 1, the voltage measuring device 403 is for measuring the output signal of the acoustic emission (AE) sensor 301. By setting, for example, a single trigger to the voltage measuring device 403, it is possible to record the moment when a voltage exceeding a certain level is generated.

　It is necessary to change the single-trigger threshold voltage depending on the surrounding noise situation or device combination. The method of determining the threshold voltage is, for example, as follows. A bending test is performed in advance on the printed wiring board 102 on which the ceramic electronic component 101 is not mounted, and the maximum value of the voltage generated at that time is measured. Specifically, an acoustic emission (AE) sensor 301 is adhered with an adhesive 304 to a printed wiring board 102 on which no ceramic electronic component 101 is mounted. The printed wiring board 102 in this state is placed on the support table 203, and a load is applied by the load application device 201 up to the indentation dimension to be measured, and a bending test is performed. A voltage measuring device 403 acquires the maximum value of the voltage signal generated in the acoustic emission (AE) sensor 301, and a value higher than the maximum signal is taken as the trigger voltage. More preferably, the bending test is performed multiple times on printed wiring board 102 on which ceramic electronic component 101 is not mounted, and the standard deviation of the maximum voltage value is obtained. A trigger voltage is obtained by adding a value obtained by multiplying the standard deviation by 3, 2 or 1 to the average value of the maximum voltage values.

The load applying device stop processing unit 500 is for stopping the load applying device 201 based on the output signal measured by the voltage measuring device 403 when the ceramic electronic component 101 is destroyed. The load applying device stop processing unit 500 is connected to the voltage measuring device 403 using, for example, a coaxial cable. Further, the load applying device stop processing unit 500 is connected to the load applying device 201 using, for example, an interface connector.

Next, operation of the measuring device 1 according to the present embodiment will be described with reference to FIGS. 4 and 5. FIG.
FIG. 4 is a flow chart showing the operation of the measuring device 1 according to this embodiment. FIG. 5 is a partial front view schematically showing how the pusher 202 of the measuring device 1 according to this embodiment pushes the object 100 to be measured.

As shown in FIGS. 4 and 5, first, a printed wiring board 102 on which ceramic electronic components 101 are mounted is prepared (S1).

Next, an acoustic emission (AE) sensor 301 is attached to the measurement object 100 (S2). An acoustic emission (AE) sensor 301 is fixed to the measurement target 100 using an adhesive 304 .

The object 100 to be measured is placed on the support table 203 (S3). After the acoustic emission (AE) sensor is fixed to the measurement target 100 using an adhesive 304, the measurement target 100 is placed on the support base 203 so that the surface of the printed wiring board 102 on which the ceramic electronic component 101 is mounted faces downward. be placed.

In this state, the bending test is started using the load application device 201. In this state, the load applying device 201 applies a load to the object 100 to be measured. A pusher 202 connected to the load applying device 201 pushes the measurement object 100 (S4).

When a crack occurs in the ceramic electronic component 101, the acoustic emission (AE) sensor 301 captures the vibration. When the ceramic electronic component 101 cracks, an acoustic emission (AE) sensor 301 detects the vibration and produces a voltage signal. This results in a higher voltage than in the unbend-tested state. A voltage measuring device 403 captures the moment when this voltage signal is generated. This voltage signal is detected by the voltage measuring device 403, a signal is sent to the load applying device stop processor 500, a test stop command is sent to the load applying device 201, and the load applying device 201 is stopped. In this way, the load application device 201 stops at the moment a crack occurs. That is, the voltage measuring device 403 detects a change in the measurement object 100, and the load applying device 201 stops (S5).

The indentation dimension of the crack is measured from the stop position of the load applying device 201 . The indentation dimension of the load applying device 201 is recorded (S6). The indentation dimension of the load applying device 201 is recorded in a recording unit (not shown). The resistance to bending of the printed board of the measurement object 100 can be measured from the indentation dimension of the load applying device 201 . The measurement target 100 is removed from the load application device 201 (S7).

By measuring the calibration curve of the indentation dimension and the amount of strain, the indentation dimension can be converted into the amount of strain. A calibration curve of the indentation dimension and the amount of strain is measured using, for example, a strain gauge. The strain gauge is preferably one capable of measuring triaxial strain.

By converting the indentation dimension of the printed wiring board 102 when a crack occurs in the ceramic electronic component 101 into a strain amount and increasing the measurement by n, it is possible to measure the actual distribution of the bending resistance of the printed board. Note that "increase by n" means measurement in which the total number of samples to be measured is increased.

FIG. 6 is a bottom view of the measurement object 100 schematically showing the contact position PP of the pusher 202 on the measurement object 100. FIG. As shown in FIG. 6, when the pusher 202 is a two-point load, the installation position IP of the acoustic emission (AE) sensor 301 is set closer to the ceramic electronic component 101 than the contact position PP of the pusher 202. be. The contact position PP of the pusher 202 functions as a load point.

FIG. 7 is a front view schematically showing a modification of the measuring device 1 according to Embodiment 1. FIG. As shown in FIG. 7, the pusher 202 may be a single point load.

Next, a measurement method according to Embodiment 1 will be described with reference to FIGS. 1 and 8. FIG.
FIG. 8 is a flow chart showing a measuring method according to Embodiment 1. FIG. The measuring method according to the first embodiment is a measuring method for measuring the printed board bending resistance of ceramic electronic component 101 mounted on printed wiring board 102 . The measurement method includes the following steps. Printed wiring board 102 is placed on support base 203 (S10). The printed wiring board 102 placed on the support table 203 is pressed by the presser 202 connected to the load applying device 201 (S20). Acoustic emission (AE) sensor 301 detects changes occurring in ceramic electronic component 101 when printed wiring board 102 is pressed against pusher 202 and ceramic electronic component 101 is destroyed (S30). Acoustic emission (AE) sensor 301 is attached to surface S1 of printed wiring board 102 on which ceramic electronic component 101 is mounted.

Next, the effects of this embodiment will be described in comparison with a comparative example.
FIG. 9 is a partial front view schematically showing the measuring device 1 of Comparative Example 1. FIG. In the measurement device 1 of Comparative Example 1, the acoustic emission (AE) sensor 301 is incorporated inside the support base 203 . Ceramic electronic component 101 is attached to support base 203 . A pusher 202 is pushed into the ceramic electronic component 101 as indicated by the white arrow in FIG. The measurement apparatus 1 of Comparative Example 1 evaluates the occurrence of cracks CR generated starting from the point of contact between the ceramic electronic component 101 and the pusher 202 . On the other hand, the measuring apparatus 1 according to the present embodiment evaluates the crack CR that starts near the electrodes of the ceramic electronic component 101 . Therefore, the mode of the crack CR to be evaluated differs between the measuring apparatus 1 of Comparative Example 1 and the measuring apparatus 1 according to the present embodiment.

FIG. 10 is a partial front view schematically showing the measuring device 1 of Comparative Example 2. FIG. In measuring apparatus 1 of Comparative Example 2, acoustic emission (AE) sensor 301 is attached to printed wiring board 102 . Ceramic electronic component 101 is mounted on printed wiring board 102 . A pusher 202 is pushed into the printed wiring board 102 as indicated by the white arrow in FIG. In the measuring device 1 of Comparative Example 2, the vibration generated by the crack CR is transmitted through the ceramic electronic component 101, the solder 103, the copper pad 102A of the printed wiring board 102, the printed wiring board 102, the support base 203, and the AE sensor 301. . In this case, since many objects with different physical properties are passed through, the vibration caused by the crack CR is attenuated, and the vibration may not be detected. Evaluation is particularly difficult for small-sized parts.

FIG. 11 is a partial front view schematically showing the measuring device 1 according to this embodiment. According to measuring apparatus 1 of the present embodiment, acoustic emission (AE) sensor 301 is attached to surface S1 of printed wiring board 102 on which ceramic electronic component 101 is mounted. In this embodiment, acoustic emission (AE) sensor 301 is directly fixed to copper pad 102 A of printed wiring board 102 . The vibration generated by the crack CR is transmitted through the ceramic electronic component 101, the solder 103, the copper pad 102A of the printed wiring board 102, the AE sensor 301, and a shorter path than in Comparative Example 2. Therefore, the vibration caused by the crack can be detected more reliably. Therefore, the crack CR generated in the ceramic electronic component 101 can be detected with higher precision than in Comparative Examples 1 and 2. Therefore, the bending resistance of the printed board can be evaluated with high accuracy. In addition, it is possible to accurately evaluate the actual distribution of bending resistance of the printed board.

With the measuring device 1 according to the present embodiment, it is possible to measure the distribution data of the bending resistance of the printed board. It becomes possible to calculate an approximate curve of the failure rate from the distribution data. Since the distribution data follows the Weibull distribution, for example, it is possible to calculate the approximate curve by obtaining the coefficients of the Weibull line from the method of least squares. It becomes possible to calculate the value of the failure rate for an arbitrary amount of strain from the approximation curve. Therefore, it becomes possible to estimate the lower limit of the failure rate or distribution by numerical analysis.

According to the measuring device 1 according to this embodiment, the voltage measuring device 403 measures the output signal of the acoustic emission (AE) sensor 301 . The load applying device stop processor 500 stops the load applying device 201 based on the output signal measured by the voltage measuring device 403 when the ceramic electronic component 101 is destroyed. Therefore, the indentation dimension of the load applying device 201 can be measured. The bending resistance of the printed board can be measured from the indentation dimension of the load applying device 201 .

According to the measurement method according to the present embodiment, acoustic emission (AE) sensor 301 is attached to surface S1 of printed wiring board 102 on which ceramic electronic component 101 is mounted. Therefore, the bending resistance of the printed board can be evaluated with high accuracy. In addition, it is possible to accurately evaluate the actual distribution of bending resistance of the printed board.

Embodiment 2.
Unless otherwise specified, the measuring device according to Embodiment 2 has the same configuration, operation, and effects as those of the measuring device according to Embodiment 1. FIG.

FIG. 12 is a front view schematically showing the configuration of a measuring device 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method according to Embodiment 2 is applied. FIG. 13 is a block diagram showing the configuration of a measuring apparatus 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method is applied according to the second embodiment. FIG. 14 is a partial front view schematically showing how the pusher 202 of the measuring device 1 according to this embodiment pushes the object 100 to be measured.

As shown in FIGS. 12 to 14, in the measuring device 1 according to Embodiment 2, the crack occurrence signal processing section 400 includes an amplifier 401, a frequency filter 402, and a voltage measuring device 403. Amplifier 401 is for amplifying the output signal of acoustic emission (AE) sensor 301 . The frequency filter 402 is for narrowing down the frequency band of the output signal of the acoustic emission (AE) sensor 301 amplified by the amplifier 401 .

The acoustic emission (AE) sensor 301 and amplifier 401 are connected using, for example, a coaxial cable. The amplifier 401 and frequency filter 402 are also connected using, for example, a coaxial cable. The frequency filter 402 and voltage measuring device 403 are also connected using, for example, a coaxial cable. The gain of the amplifier 401 is adjusted to, for example, 10 dB or more and 1000 dB or less. Also, the frequency filter 402 is adjusted to a frequency band of, for example, 10 kHz or more and 1000 kHz or less. An oscilloscope, for example, is used as the voltage measuring device 403 . In the voltage measurement device 403, the voltage measurement range is set to, for example, -10 V to +10 V, and the trigger voltage is set to +1 mV or more or -1 mV or less.

The set value of the frequency filter 402 needs to be changed according to the environment to be measured or the object to be measured. A method for confirming the set value of the frequency filter 402 is, for example, as follows. A bending test is performed in advance on the printed wiring board 102 on which the ceramic electronic component 101 is not mounted, and the frequency filter 402 is determined from the frequency characteristics of the voltage generated at that time. Specifically, the AE sensor 301 is adhered with an adhesive 304 to the printed wiring board 102 on which the ceramic electronic component 101 is not yet mounted. The printed wiring board 102 in this state is placed on the support table 203, and a load is applied by the load application device 201 up to the indentation dimension to be measured, and a bending test is performed. For example, if the voltage measuring device 403 is set to a single trigger with a voltage equal to or higher than the maximum value of background noise, the vibration generated by the bending of the printed wiring board 102 on which the ceramic electronic component 101 is not mounted can be captured. There is A frequency peak is confirmed by FFT (Fast Fourier Transform) analysis of the obtained waveform. A high-pass filter, a low-pass filter, or a band-pass filter, for example, is set so that no identified frequency peaks are acquired.

The addition of the frequency filter 402 suppresses the influence of noise such as vibration due to disconnection of the fibers of the printed wiring board 102 or friction between the printed wiring board 102 and the support base 203 . Therefore, only vibration caused by cracks in the ceramic electronic component 101 can be detected. Further, by adding the amplifier 401, it becomes possible to measure a small-sized ceramic electronic component 101 which is difficult to detect. The small-size ceramic electronic component 101 is, for example, a ceramic electronic component 101 having a length of less than 3.2 mm, a width of less than 1.6 mm, and a thickness of less than 1.6 mm.

According to the measuring device 1 according to Embodiment 2, the amplifier 401 amplifies the output signal of the acoustic emission (AE) sensor 301 . Therefore, even small-sized ceramic electronic components 101 that are difficult to detect by the amplifier 401 can be measured. Further, the load applying device stop processing section 500 stops the load applying device 201 based on the output signal measured by the voltage measuring device 403 when the ceramic electronic component 101 is destroyed. Therefore, it is possible to suppress the influence of noise such as vibration due to disconnection of the fibers of the printed wiring board 102 or friction between the printed wiring board 102 and the support base 203 . In other words, it becomes possible to detect only the vibration caused by the crack CR generated in the ceramic electronic component 101 .

Embodiment 3.
Unless otherwise specified, the measurement device according to Embodiment 3 has the same configuration, operation, and effects as those of the measurement device according to Embodiment 2.

FIG. 15 is a front view schematically showing the configuration of a measuring device 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method according to Embodiment 3 is applied. FIG. 16 is a block diagram showing the configuration of a measuring apparatus 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method is applied according to the third embodiment.

As shown in FIGS. 15 and 16, in the measuring device 1 according to Embodiment 3, the crack occurrence detection section 300 includes an acoustic emission (AE) sensor 301, a fixture 302, and glycerin 303.

17 shows an example of connection between the rubber portion 302A and the metal portion 302B of the fixing jig 302. FIG. As shown in FIG. 17 , fixture 302 is for fixing acoustic emission (AE) sensor 301 to printed wiring board 102 . The fixing jig 302 includes a rubber portion 302A and a metal portion 302B. A knot K is provided at each end of the rubber portion 302A. The rubber portion 302A has two knots K. Holes H are provided at both ends of the metal portion 302B. The metal portion 302B has two holes H. The knots K of the rubber portion 302A are configured to be caught in the holes H of the metal portion 302B. Both ends of the rubber portion 302A are passed through the holes H, respectively. The rubber part 302A is not separated from the metal part 302B by forming a knot K at the tip of the hole H. The maximum dimension of the knot K is larger than the inner diameter of the hole H.

The material of the rubber portion 302A is, for example, natural rubber. The width of the rubber portion 302A is adjusted to be smaller than the diameter or width of the acoustic emission (AE) sensor 301. FIG. The length of the rubber portion 302A is such that when the rubber portion 302A is raised by the height of the acoustic emission (AE) sensor 301 with the metal portion 302B fixed, a tensile load of 1.0 N or more and 99.0 N or less is applied. adjusted to The material and thickness of the metal portion 302B may be any material and thickness that do not deform due to the tension of the rubber portion 302A. Since the rubber portion 302A deteriorates over time, it is renewed every other month, for example.

FIG. 18 is a perspective view schematically showing a state in which an acoustic emission (AE) sensor 301 is fixed using a fixing jig 302 to the printed wiring board 102 on which the ceramic electronic component 101 is mounted. As shown in FIG. 18, after glycerin 303 is applied to printed wiring board 102, acoustic emission (AE) sensor 301 is mounted on printed wiring board 102, and rubber portion 302A and metal portion 302B of fixture 302 are attached. It is fixed by sandwiching it between The fixing jig 302 is mounted on the printed wiring board so that the rubber portion 302A contacts the acoustic emission (AE) sensor 301 and the metal portion 302B contacts the surface S2 of the printed wiring board 102 on which the ceramic electronic component 101 is not mounted. 102 and an acoustic emission (AE) sensor 301 .

The fixed position of the acoustic emission (AE) sensor 301 is set on the printed wiring board 102 closer to the ceramic electronic component 101 than the fulcrum of the support base 203 . A fixed location for the acoustic emission (AE) sensor 301 is preferably located near the ceramic electronic component 101 . Incidentally, the acoustic emission (AE) sensor 301 may be of a size that can be placed on the printed wiring board 102 . The amount of glycerin 303 applied is adjusted to 0.01 ml or more and 1.00 ml or less.

Regarding the setting method of the frequency filter 402, for example, a bending test is performed in advance on the printed wiring board 102 on which the ceramic electronic component 101 is not mounted, and the frequency filter 402 is determined from the frequency characteristics of the voltage generated at that time. Specifically, after glycerin 303 is applied to printed wiring board 102 on which ceramic electronic component 101 is not yet mounted, acoustic emission (AE) sensor 301 is mounted, and rubber portion 302A of fixing jig 302 and metal are mounted. It is fixed so as to be sandwiched between portions 302B. The printed wiring board 102 in this state is placed on the support table 203, and a load is applied by the load application device 201 up to the indentation dimension to be measured, and a bending test is performed. If the voltage measuring device 403 is set to a single trigger, for example, a voltage higher than the maximum value of background noise, the vibration generated by the bending of the printed wiring board 102 on which the ceramic electronic component 101 is not mounted can be captured. There is A frequency peak is confirmed by FFT-analyzing the obtained waveform. A high-pass filter, a low-pass filter, or a band-pass filter, for example, is set so that no identified frequency peaks are acquired.

The set voltage of the single trigger is determined, for example, from the maximum value of the voltage generated at the bending test performed in advance on the printed wiring board 102 on which the ceramic electronic component 101 is not mounted. Specifically, after glycerin 303 is applied to printed wiring board 102 on which ceramic electronic component 101 is not yet mounted, acoustic emission (AE) sensor 301 is mounted, and rubber portion 302A of fixing jig 302 and metal are mounted. It is fixed so as to be sandwiched between portions 302B. The printed wiring board 102 in this state is placed on the support base 203, and a load is applied by the load applying device 201 to the indentation dimension to be measured, and the bending test is performed. A voltage measuring device 403 obtains the maximum value of the voltage signal generated in the acoustic emission (AE) sensor 301, and the value higher than the maximum signal is taken as the trigger voltage. More preferably, the bending test is performed multiple times on printed wiring board 102 on which ceramic electronic component 101 is not mounted, and the standard deviation of the maximum voltage value is obtained. A value obtained by adding a value obtained by multiplying the standard deviation by 3, 3 or 1 to the average value of the maximum voltage value is taken as the trigger voltage.

By fixing the acoustic emission (AE) sensor 301 to the printed wiring board 102 using the fixing jig 302, it becomes easier to attach and detach than when the adhesive 304 is used. Therefore, in n-increment evaluation, evaluation can be performed in a shorter time than when the adhesive 304 is used. It should be noted that n-added evaluation is evaluation of measurement in which the total number of samples to be measured is increased.

As a verification of the effect, the inventors of the present application measured the printed board bending resistance of a laminated ceramic capacitor having a length of 1.6 mm, a width of 0.8 mm, a thickness of 0.8 mm, a capacitance of 0.01 μF, and a withstand voltage of 50 V. . FIG. 19 is a graph showing distributions of the cumulative failure rate P% and the amount of strain (μST) of the multilayer ceramic capacitor measured by the measuring apparatus according to the present embodiment, using a 3-parameter Weibull distribution. Note that the n number is 22. That is, the total number of samples measured is 22. The number of plots in the graph is the number of samples judged to be faulty. The Y-axis spacing is about 5% (=1/22) and is related to the n number.

When comparing the data measured by this method with the comparison data of the failure rate of ceramic electronic components subjected to a load equivalent to 1 mm and 2 mm bending according to the bending resistance method of printed boards specified in JISC5101-22, the results are equivalent. It was confirmed that the results of In addition, the failure rate of the comparison data was determined by cross-sectional observation. Regarding the cross-sectional observation method, for example, the laminated ceramic capacitor is removed from the printed wiring board 102 and the single chip is embedded in resin. Next, the resin block in which the multilayer ceramic capacitor is embedded in the resin is polished so that the mounting surface and the vertical surface of the multilayer ceramic capacitor can be observed. Where the cross section of the multilayer ceramic capacitor can be seen, the cross section is observed. A sample in which a crack originating near the end of the external electrode reaches the internal electrode is determined to be faulty. More preferably, a plurality of cross sections are observed to confirm the presence or absence of cracks.

In addition, the inventors of the present application have found that, among multilayer ceramic capacitors having the characteristics of length 1.6 mm, width 0.8 mm, thickness 0.8 mm, capacitance of 3300 pF, and withstand voltage of 50 V, printed board-resistant products from different manufacturers Flexibility was measured. FIG. 20 is a graph showing cumulative failure rate distributions of laminated ceramic capacitors measured by the measuring apparatus according to the present embodiment, and comparing characteristics between manufacturers using a 3-parameter Weibull distribution. Incidentally, the number of n is 22. The number of plots in the graph is the number of samples judged to be faulty. The Y-axis spacing is about 5% (=1/22) and is related to the n number. A cumulative failure rate plot of the laminated ceramic capacitor of Company A and a cumulative failure rate plot of the laminated ceramic capacitor of Company B are shown. Data such as that shown in FIG. 20 is useful, for example, when comparing performance by manufacturer when adopting a product. In addition, data such as those shown in FIG. 20 are also useful for evaluation of variations in products depending on the time of manufacture even after adoption of the products.

As an alternative to the fixing jig 302, for example, vinyl tape may be used. When a vinyl tape is used, the voltage intensity or frequency peak of the vibration due to peeling of the vinyl tape is obtained in advance and classified as vibration due to cracks occurring in the ceramic electronic component 101 .

According to the measuring device 1 according to this embodiment, the fixing jig 302 fixes the acoustic emission (AE) sensor 301 to the printed wiring board 102 . Fixing the acoustic emission (AE) sensor 301 to the printed wiring board 102 using the fixing jig 302 makes attachment and detachment easier than when using the adhesive 304 . Therefore, in n-increment evaluation, evaluation can be performed in a shorter time than when the adhesive 304 is used.

Embodiment 4.
Unless otherwise specified, the measurement device according to Embodiment 4 has the same configuration, operation, and effects as those of the measurement device according to Embodiment 3.

FIG. 21 is a front view schematically showing the configuration of a measuring device 1 for measuring the bending resistance of a printed board to which the acoustic emission (AE) method according to Embodiment 4 is applied. FIG. 22 is a block diagram showing the configuration of a measuring apparatus 1 for measuring the bending resistance of printed boards to which the acoustic emission (AE) method is applied according to the fourth embodiment.

As shown in FIG. 22 , the measuring device 1 according to Embodiment 4 includes an adhesion confirmation section 600 for confirming adhesion between the crack generation detection section 300 and the printed wiring board 102 . The adhesion confirmation unit 600 includes an acoustic emission (AE) sensor (vibrating body) 601 for vibration. Further, the adhesion confirmation unit 600 includes an AC voltage output device 602 and glycerin 603 . A vibration acoustic emission (AE) sensor 601 is electrically connected to an AC voltage output device 602 .

The vibration acoustic emission (AE) sensor 601 has, for example, a diameter of φ5 [mm], a height of 3.2 [mm], and a weight of 0.2 g. A power supply capable of outputting a sine wave with an amplitude of up to 10 [Vp-p] at a frequency of 1 kHz or more and 1 MHz or less is used for the AC voltage output device 602, for example.

FIG. 23 is a perspective view schematically showing a state in which an acoustic emission (AE) sensor 301 is fixed using a fixing jig 302 to the printed wiring board 102 on which the ceramic electronic component 101 is mounted. As shown in FIG. 23, the metal portion 302B of the fixture 302 is provided with non-through holes NH. A vibration acoustic emission (AE) sensor 601 is embedded in the non-through hole NH. In the present embodiment, the vibration acoustic emission (AE) sensor 601 is embedded and fixed after applying glycerin 603 to the non-through hole NH provided in the metal portion 302B.

The frequency output by the AC voltage output device 602 is set at the resonance point of the acoustic emission (AE) sensor 601 for vibration and within the measurable range of the acoustic emission (AE) sensor 301 . The voltage output by the AC voltage output device 602 is obtained by installing the acoustic emission (AE) sensor 301 on the printed wiring board 102 and fixing it using the fixing jig 302, and then applying the voltage from the AC voltage output device 602. At that time, the voltage is adjusted so as to fall within the voltage measurement range of the voltage measurement device 403 .

The depth of the non-through hole NH of the metal portion 302B should be less than the thickness of the metal portion 302B. The depth of the non-through hole NH of the metal portion 302B is, for example, 1.2 mm when the thickness of the metal portion 302B is 1.6 mm. The hole diameter of the non-through hole NH of the metal part 302B has a fitting tolerance to such an extent that the vibration acoustic emission (AE) sensor 601 does not easily move after the vibration acoustic emission (AE) sensor 601 is embedded. All you have to do is The hole diameter of the non-through hole NH of the metal portion 302B is, for example, φ5.012 [mm] when using an acoustic emission (AE) sensor with a diameter of φ5 [mm].

The vibration acoustic emission (AE) sensor 601 may be fixed to the metal portion 302B using an adhesive.

With the acoustic emission (AE) sensor 301 fixed to the printed wiring board 102 by the fixing jig 302 , the printed wiring board 102 is placed on the support base 203 . After that, an AC voltage is applied from the AC voltage output device 602 to the vibration acoustic emission (AE) sensor 601 . A vibrating acoustic emission (AE) sensor 601 vibrates when an alternating voltage is applied. The generated vibration reaches the acoustic emission (AE) sensor 301 via the metal portion 302B, the printed wiring board 102, and the glycerin 303. FIG. When acoustic emission (AE) sensor 301 receives vibrations, the vibrations are converted into voltages and detected by voltage measuring device 403 .

When the adhesion between the acoustic emission (AE) sensor 301 and the printed wiring board 102 is high, the voltage Vp-p detected by the voltage measuring device 403 is printed such that the acoustic emission (AE) sensor 301 is lifted from the board. It is more than double that when the adhesion to the wiring board 102 is low.

When it is determined from the detected voltage that there is no problem with the adhesion, the output of the AC voltage output device 602 is stopped, and the bending resistance evaluation of the printed board described in Embodiment 3 is continued.

When it is judged that there is a problem with the adhesion from the detected voltage, the output of the AC voltage output device 602 is stopped, the printed wiring board 102 is removed from the support, and the acoustic emission (AE) sensor 301 is printed. It is removed from the wiring board 102 . After that, the process of attaching the acoustic emission (AE) sensor 301 to the printed wiring board 102 is restarted.

The measurement method according to the fourth embodiment is based on the detection sensitivity of the vibration generated by the vibration acoustic emission (AE) sensor (vibrating body) 601 detected by the acoustic emission (AE) sensor 301, and the acoustic emission (AE) sensor and the printed wiring. A step of evaluating adhesion with the plate 102 is further provided.

According to the fourth embodiment, by adding a step of evaluating the adhesion between the acoustic emission (AE) sensor 301 and the printed wiring board 102, the bending resistance of the printed board can be evaluated in a state where the adhesion is poor. can be avoided. Therefore, it is possible to reduce measurement errors due to poor adhesion. Therefore, evaluation with higher precision becomes possible.

The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the above description, and is intended to include all changes within the meaning and scope of equivalence to the scope of claims.

1 measuring device, 100 object to be measured, 101 ceramic electronic component, 102 printed wiring board, 102A copper pad, 103 solder, 200 load application unit, 201 load application device, 202 plunger, 203 support base, 300 crack detection unit, 301 Acoustic emission (AE) sensor, 302 fixing jig, 302A rubber part, 302B metal part, 303 glycerin, 304 adhesive, 400 crack generation signal processing part, 401 amplifier, 402 frequency filter, 403 voltage measuring device, 500 load applying device Stop processing part, 600 Adhesion confirmation part, 601 Acoustic emission (AE) sensor for vibration, 602 AC voltage output device, 603 Glycerin, H hole, K knot.

Claims

A measuring device for measuring the printed board bending resistance of a ceramic electronic component mounted on a printed wiring board,
a support for mounting the printed wiring board;
a load applying device for applying a load to the printed wiring board placed on the support;
a presser connected to the load applying device for pressing the printed wiring board with the load applied from the load applying device;
an acoustic emission sensor for detecting a change occurring in the ceramic electronic component when the ceramic electronic component is destroyed by the printed wiring board being pressed against the pusher;
The measurement device, wherein the acoustic emission sensor is configured to be attached to a surface of the printed wiring board on which the ceramic electronic component is mounted.
a voltage measuring device for measuring an output signal of the acoustic emission sensor;
2. The apparatus according to claim 1, further comprising a load applying device stop processing section for stopping said load applying device based on said output signal measured by said voltage measuring device when said ceramic electronic component is broken. Measurement device as described.
an amplifier for amplifying the output signal of the acoustic emission sensor;
3. The measuring apparatus according to claim 2, further comprising a frequency filter for narrowing down the frequency band of said output signal of said acoustic emission sensor amplified by said amplifier.
further comprising a fixture for fixing the acoustic emission sensor to the printed wiring board;
The fixing jig includes a rubber portion and a metal portion,
A knot is provided at each end of the rubber part,
Holes are provided at both ends of the metal part,
The knots of the rubber portion are configured to be caught in the holes of the metal portion, respectively,
The fixing jig is arranged so that the rubber portion contacts the acoustic emission sensor and the metal portion contacts the surface of the printed wiring board on which the ceramic electronic component is not mounted. 4. The measuring device according to any one of claims 1 to 3, which is configured to sandwich an emission sensor.
further comprising a vibrating body,
A non-through hole is provided in the metal portion of the fixing jig,
The measuring device according to claim 4, wherein the vibrator is embedded in the non-through hole.
A measuring method for measuring the printed board bending resistance of a ceramic electronic component mounted on a printed wiring board,
a step of placing the printed wiring board on a support;
a step of pressing the printed wiring board placed on the support base against a pusher connected to a load applying device;
an acoustic emission sensor detecting a change occurring in the ceramic electronic component when the ceramic electronic component is destroyed by the printed wiring board being pressed against the pusher;
The measuring method, wherein the acoustic emission sensor is attached to the surface of the printed wiring board on which the ceramic electronic component is mounted.
The measuring method according to claim 6, further comprising a step of evaluating the adhesion between the acoustic emission sensor and the printed wiring board based on the detection sensitivity of the acoustic emission sensor to the vibration generated by the vibrating body.