WO2013035357A1

WO2013035357A1 - Continuity inspection apparatus and continuity inspection method

Info

Publication number: WO2013035357A1
Application number: PCT/JP2012/055068
Authority: WO
Inventors: 高野　祥司; 松田　文彦
Original assignee: 日本メクトロン株式会社
Priority date: 2011-09-08
Filing date: 2012-02-29
Publication date: 2013-03-14
Also published as: JP2013057597A; CN103097901B; JP5797502B2; CN103097901A

Abstract

[Problem] The purpose of the present invention is to provide a continuity inspection apparatus and a continuity inspection method whereby an occurrence of disconnection in a multiple wiring pattern can be reliably detected at low cost. [Solution] A continuity inspection apparatus (100) has a first terminal, a second terminal, and a plurality of wiring lines that electrically connect the first and the second terminals to each other, and performs continuity inspection of a multiple wiring pattern. The continuity inspection apparatus is provided with: an inductance measuring unit (110), which measures an inductance value between the first terminal and the second terminal; a continuity determining unit (120), which compares the inductance value and a predetermined continuity determining threshold value with each other, and on the basis of the results, which determines that disconnection occurred in the multiple wiring pattern if the inductance value is larger than the continuity determining threshold value, and determines that there is no disconnection occurred if the inductance value is not larger than the continuity determining threshold value; a storage unit (130) that stores the continuity determining threshold value; and a display unit (140) that displays results determined by means of the continuity determining unit (120).

Description

Continuity inspection device and continuity inspection method

The present invention relates to a continuity inspection apparatus and a continuity inspection method, and more particularly, to a continuity inspection apparatus and a continuity inspection method of a multiple wiring pattern provided on a printed wiring board.

It is known that there are mainly a pin contact method and a non-contact method as a method of continuity check of a wiring pattern provided on a printed wiring board (Patent Document 1).

In the pin contact method, probe pins are brought into direct contact with both ends of a wiring pattern of a printed wiring board to be inspected, and a current is supplied to one of the probe pins. Then, the continuity check of the wiring pattern is performed by obtaining the DC resistance value of the wiring pattern from the voltage value detected by the other probe pin (see paragraphs [0002] and [0003] of Patent Document 1).

On the other hand, in the non-contact method, the probe pin is brought into direct contact with one end of the wiring pattern of the printed wiring board to be inspected to apply an inspection signal including an AC component, and the other end is non-contact Conductivity inspection of the wiring pattern is performed by detecting a signal (see paragraph [0004] of Patent Document 1).

Patent No. 3311698 JP 2002-148290 A

However, it is difficult to conduct a continuity test of the multiple wiring pattern by using any of the above inspection methods. The multiple wiring pattern refers to a wiring pattern having a first terminal and a second terminal, and having a plurality of wirings electrically connecting the first and second terminals. The multiple wiring pattern is used, for example, for the purpose of reducing the impedance of a circuit, or for the purpose of dispersing a large current into a plurality of wires to reduce the current flowing through one wire.

FIG. 7 shows a configuration example of the multiple wiring pattern. FIG. 7A is a top view of the double-sided printed wiring board 51 provided with the multiple wiring pattern, and FIG. 7B is a cross-sectional view taken along the line A-A 'of FIG. 7A.

Conductor patterns

53A and 53B are formed on the front and back surfaces of the insulating substrate 52, respectively. As shown in FIG. 7A, the conductor pattern 53B is formed thicker than the conductor pattern 53A.

The conductor pattern 53A has a wire 54, and

terminals

55 and 56 at both ends of the wire 54. Similarly, the conductor pattern 53 </ b> B has a wire 57 and

terminals

58 and 59 at both ends of the wire 57. Then, as shown in FIG. 7B, the terminal 55 and the terminal 58 are electrically connected by the through via 60, and similarly, the terminal 56 and the terminal 59 are electrically connected by the through via 61. Thus, the double-sided printed wiring board 51 is provided with a multiplex wiring pattern having two wires.

That is, a first wiring and a second wiring which have a terminal 55 as a first terminal and a terminal 56 as a second terminal and which electrically connect the first terminal and the second terminal are used. Have. The first wiring is the wiring 54, and the second wiring is composed of the conductor pattern 53B, the through via 60, and the through via 61.

The resistance of the second wiring is larger than the resistance of the first wiring because the resistance due to the

through vias

60 and 61 is present in addition to the conductive pattern 53B being thinner than the conductive pattern 53A. For this reason, when the continuity test is performed by the pin contact method, it may not be possible to detect that the first wire having a resistance value lower than that of the second wire is broken due to the dimensional variation of each element constituting the wire. There is.

When the continuity test is performed by the non-contact method, when any one of the first wiring and the second wiring is broken, the inspection signal is detected from the wiring which is not broken. Therefore, in the non-contact method, it is impossible in principle to detect that any one of the first wiring and the second wiring is broken.

As described above, in the pin contact method and the non-contact method, it is not possible to reliably detect that a part of the plurality of wires constituting the multiple wiring pattern is broken.

In addition, as a method of detecting the disconnection of the multiple wiring pattern, a method using a TDR (time domain reflectometer) oscilloscope may be mentioned (see Patent Document 2). Using the TDR oscilloscope, in principle, it can also be detected that a part of the multiple wiring pattern is broken. However, since the TDR oscilloscope apparatus is expensive, there is a problem that the inspection cost increases.

The present invention has been made based on the above recognition, and it is an object of the present invention to provide a continuity inspection apparatus and a continuity inspection method capable of reliably and inexpensively detecting the occurrence of disconnection in a multiple wiring pattern. To aim.

According to one aspect of the present invention, a continuity test is performed on a multiple wiring pattern having a first terminal and a second terminal, and having a plurality of wires electrically connecting the first and second terminals. In the continuity inspection apparatus, an inductance measurement unit for measuring an inductance value between the first terminal and the second terminal is compared with the inductance value and a threshold for conduction determination, and the inductance value is determined as the conduction. And a continuity determining unit that determines that disconnection is occurring in the multiple wiring pattern if the threshold value is larger than the threshold value, and determines that no disconnection occurs otherwise. Provided.

According to another aspect of the present invention, a continuity test is performed on a multiple wiring pattern having a first terminal and a second terminal and having a plurality of wires electrically connecting the first and second terminals. In the continuity inspection method, an inductance value between the first terminal and the second terminal is measured, the inductance value is compared with a threshold for conduction determination, and the inductance value is higher than the threshold for conduction determination. If the value is larger, it is determined that the disconnection occurs in the multiple wiring pattern, and if not, it is determined that the disconnection does not occur.

According to the present invention, occurrence of disconnection in the multiple wiring pattern can be detected reliably and inexpensively.

FIG. 1 is a block diagram showing a schematic configuration of a continuity inspection device according to a first embodiment of the present invention. It is a figure which shows the structure of the inductance measurement part by a 4 terminal pair method. It is a graph which shows the range of the inductance value of a multiplex wiring pattern when the dimensional variation of wiring is considered. It is a figure which shows the measurement result of the inductance value of a multiple wiring pattern. It is a block diagram which shows schematic structure of the continuity test apparatus which concerns on the 2nd Embodiment of this invention. It is a flow chart which shows the continuity inspection method concerning a 2nd embodiment. (A) is a top view which shows the structural example of the multiple wiring pattern provided in the double-sided printed wiring board, (b) is sectional drawing which follows the A-A 'line | wire of (a).

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the component which has an equivalent function in each figure, and the detailed description of the component of the same code is not repeated.

First Embodiment
FIG. 1 is a block diagram showing a schematic configuration of the continuity inspection device 100 according to the first embodiment. The continuity inspection apparatus 100 includes an inductance measurement unit 110, a continuity determination unit 120, a storage unit 130, and a display unit 140.

The inductance measuring unit 110 measures an inductance value between the first terminal and the second terminal of the multiple wiring pattern. As a measuring method, a two-terminal method or a four-terminal method may be mentioned, but a four-terminal pair method capable of reducing the influence of the magnetic flux generated by the measuring current is preferable. The measurement of the inductance value by the four-terminal pair method will be described later with reference to FIG.

The conduction determination unit 120 compares the inductance value measured by the inductance measurement unit 110 with a predetermined determination threshold (threshold for conduction determination). As a result, if the inductance value is larger than the conduction determination threshold value, the conduction determination unit 120 determines that a disconnection occurs in the multiple wiring pattern, and otherwise determines that a disconnection does not occur.

The threshold value for conduction determination is smaller than the inductance value (disconnected inductance value) between the first terminal and the second terminal when disconnection occurs in the multiple wiring pattern, and when disconnection does not occur. A value larger than the inductance value (non-breaking inductance value) between the first terminal and the second terminal is used. Preferably, the disconnection inductance value is the lower limit of the range in which the inductance value at the time of disconnection can be taken due to the dimensional variation of the multiple wiring pattern, and the non-breaking inductance value is the inductance at the non-disconnection due to the dimensional variation of the multiple wiring pattern. This is the upper limit of the range of values that can be taken.

The storage unit 130 is, for example, a non-volatile memory such as a hard disk (HDD) or a flash memory, and stores the above-described threshold for conduction determination and the like. The conduction determination unit 120 reads the conduction determination threshold from the storage unit 130, and compares the inductance value measured by the inductance measurement unit 110 (or the resistance value measured by the resistance measurement unit 150 described later) with the conduction determination threshold. Do.

The display unit 140 is, for example, a liquid crystal display or a printer, and displays the determination result by the conduction determination unit 120.

Next, the configuration of the inductance measuring unit 110 in the case of adopting the four-terminal pair method will be described. FIG. 2 shows an inductance meter 16 constituting the inductance measurement unit 110, Kelvin probes 12 and 13, coaxial cables 21 to 24, and a double-sided printed wiring board 1 to be inspected.

First, the configuration of the double-sided printed wiring board 1 will be described.

Conductor patterns

3A and 3B are formed on the front and back surfaces of the insulating substrate 2, respectively. The conductor pattern 3A has a wire 4 and terminals 5 and 6 at both ends of the wire 4. Similarly, the conductor pattern 3B has a wire 7 and

terminals

8 and 9 at both ends of the wire 7.

As shown in FIG. 2, the terminals 5 and 8 are electrically connected by the through vias 10, and similarly, the terminals 6 and 9 are electrically connected by the through vias 11. Thus, the double-sided printed wiring board 1 has the terminal 5 as the first terminal and the terminal 6 as the second terminal, and electrically connects the first terminal and the second terminal. It has two wires (a first wire and a second wire). The first wiring is the wiring 4, and the second wiring is the wiring composed of the conductor pattern 3 B, the through via 10, and the through via 11.

The number of wires of the multiplex wiring pattern to be inspected in the present invention is not limited to two, and may be three or more. Further, the plurality of wires constituting the multiple wiring pattern may be branched not only in the case of branching in the vertical direction (thickness direction) of the printed wiring board as shown in FIG. 2, but may be branched in the horizontal direction It is optional.

Next, the inductance meter 16, the Kelvin probes 10 and 11, and the coaxial cables 21 to 24 constituting the inductance measurement unit 110 will be described.

The inductance meter 16 comprises an alternating current signal source 17 for passing an alternating current for measurement to the terminal 5 of the multiple wiring pattern, an alternating current ammeter 18 for measuring the alternating current flowing out from the terminal 6, and a voltage between the terminal 5 and the terminal 6 And an AC voltmeter 19 for measuring

As shown in FIG. 2, when measuring the inductance, the Kelvin probe 12 is brought into contact with the terminal 5 and the Kelvin probe 13 is brought into contact with the terminal 6.

The Kelvin probe 12 has probe pins 12a and 12b, and the Kelvin probe 13 has probe pins 13a and 13b.

Also, the inductance meter 16 has four terminals Hc, Hp, Lc and Lp. The Hc terminal is electrically connected to the terminal 5 via the coaxial cable 21 and the probe pin 12 a of the Kelvin probe 12. The Hp terminal is electrically connected to the terminal 5 via the coaxial cable 23 and the probe pin 12 b of the Kelvin probe 12. The Lc terminal is electrically connected to the terminal 6 via the coaxial cable 22 and the probe pin 13 b of the Kelvin probe 13. The Lp terminal is electrically connected to the terminal 6 via the coaxial cable 24 and the probe pin 13 a of the Kelvin probe 13.

As shown in FIG. 2, the outer conductors 21 b to 24 b of the coaxial cables 21 to 24 are electrically connected to each other by a conductor 25.

The coaxial cable 21 has a center conductor 21 a electrically connected to the output terminal of the AC signal source 17 and an outer conductor 21 b electrically connected to the input terminal of the AC signal source 17. The coaxial cable 22 has a center conductor 22 a electrically connected to the input terminal of the alternating current ammeter 18 and an outer conductor 22 b electrically connected to the output terminal of the alternating current ammeter 18. The coaxial cable 23 has a center conductor 23 a electrically connected to one terminal of the AC voltmeter 19 and an outer conductor 23 b electrically connected to the outer conductor 21 b of the coaxial cable 21. The coaxial cable 24 has a central conductor 24a electrically connected to the other terminal of the AC voltmeter 19, and an outer conductor 24b electrically connected to the outer conductor 22b of the coaxial cable 22 and the outer conductor 23b of the coaxial cable 23. And.

The probe pin 12 a is electrically connected to the center conductor 21 a of the coaxial cable 21. The probe pin 12 b is electrically connected to the central conductor 23 a of the coaxial cable 23. The probe pin 13 a is electrically connected to the center conductor 24 a of the coaxial cable 24. The probe pin 13 b is electrically connected to the central conductor 22 a of the coaxial cable 22.

The Hc terminal is connected to the AC signal source 17, and applies an AC signal to the terminal 5 through the probe pin 12a. The alternating current signal applied to the terminal 5 passes through the multiple wiring pattern, and is input to the alternating current ammeter 18 from the terminal 6 through the probe pin 13 b and the Lc terminal. The return current output from the AC ammeter 18 passes through the outer conductors (shield portions) 21b to 24b of the coaxial cables 21 to 24 and returns to the AC signal source 17.

Further, an AC voltmeter 19 is connected to the Hp terminal and the Lp terminal of the inductance meter 16 and measures the voltage between the terminal 5 and the terminal 6.

The above connection method is called four-terminal pair method. The alternating current output from the alternating current signal source 17 flows through the center conductors 21 a and 22 a of the

coaxial cables

21 and 22. On the other hand, the return current flows through the outer conductors 21b to 24b of the coaxial cables 21 to 24 and returns to the AC signal source 17. Since the measurement current and the return current flow in opposite directions in this manner, the magnetic fields generated by these currents are canceled out and no magnetic field is generated outside. Therefore, the self-inductance and the mutual inductance do not occur on the coaxial cables 21 to 24, and the inductance measuring unit 110 can measure a minute inductance. Therefore, it is possible to measure a slight difference between the inductance when one of the wiring 4 and the wiring 7 is broken and the inductance when both the wiring 4 and the wiring 7 are not broken.

The inductance measuring unit 110 obtains an inductance value between the terminal 5 and the terminal 6 by calculating a ratio of the AC voltage measured by the AC voltmeter 19 to the AC current measured by the AC ammeter 18.

The above inductance measurement method is also referred to as the IV method, and can be realized with an inexpensive configuration as compared with other measurement methods, and can stably perform measurement in a relatively low frequency band (for example, 1 kHz to 10 MHz) be able to.

The broken line in FIG. 2 indicates the path of the alternating current for measurement when no disconnection occurs. If a break occurs in the first wire, alternating current passes through the second wire. On the other hand, when disconnection occurs in the second wiring, alternating current passes through the first wiring.

The inductance of the first wiring is L1, and the inductance of the second wiring is L2. Then, let L1_2 be a combined inductance of the first wiring and the second wiring. When the first wiring and the second wiring are not disconnected, the combined inductance L1_2 is (L1 × L2) / (L1 + L2). On the other hand, when a break occurs in either one of the first wiring and the second wiring (that is, in the case of a one-sided break), the combined inductance is L1 or L2. When disconnection occurs in both the first wiring and the second wiring, the inductance value is zero.

The inductance L of the conductor pattern provided on the printed wiring board can be approximately calculated using equation (1) (http://www.zuken.co.jp/clubZ/z/analog/006/ See ana / ana_110120_1.html).

Here, l: wiring length (mm), W: wiring width (mm), T: wiring thickness (mm).

The inductance value (L1) of the first wiring and the inductance value (L2) of the second wiring are determined using Equation (1). Here, for the sake of simplicity, the sizes (length, width, thickness) of the conductor pattern 3A and the conductor pattern 3B are the same, and the through

vias

10 and 11 are ignored for the second wiring, and only the conductor pattern 3B is Consider.

Assuming that the wiring length l = 50 mm, the wiring width W = 100 μm, and the wiring thickness T = 30 μm, the values of the inductances L1 and L2 are 71.5 nH from the equation (1). The inductance value is a value when only one of the first wiring and the second wiring is disconnected. The combined inductance L1_2 is 35.7 nH when neither of the first wiring and the second wiring is disconnected.

As described above, when one-side disconnection occurs in the multiple wiring pattern, the mutual inductance disappears and only the self-inductance of the non-disconnected wiring becomes, so the inductance value becomes large. By utilizing this, it is possible to detect that one of the first wiring and the second wiring is broken. As described above, when disconnection occurs in both the first wiring and the second wiring, the inductance value between the first terminal and the second terminal is zero. Therefore, the measurement of the inductance value can also detect that both the first wiring and the second wiring are disconnected.

By the way, the wiring width W and the wiring thickness T of the actually manufactured wiring have a certain dimensional variation. Therefore, in order to conduct the continuity inspection of the multiple wiring pattern more reliably, it is desirable to consider the dimensional variation of the wiring. The variation of the wiring width W can be estimated to, for example, ± 10%, and in this case, the range of possible values of the wiring width W is 100 ± 10 μm. Further, the variation of the wiring thickness can be estimated to be, for example, ± 50%, and in this case, the range of possible values of the wiring thickness T is 30 μm ± 15 μm. The reason that the dimensional variation in the thickness direction is relatively larger than that in the width direction is because it is assumed that the

conductor patterns

3A and 3B are formed by copper plating.

The range of the inductance value in which the dimensional variation was taken into consideration was calculated using equation (1) for each of the one-sided and non-opened cases. FIG. 3 shows the calculation result, and the inductance value of the multiple wiring pattern at the time of non-breaking is 34.9 to 36.8 nH, and the inductance value of the multiple wiring pattern at the time of one-side disconnection is 69.7 to It is 73.6 nH.

Thus, even if the dimensional variation is taken into consideration, the difference Δ between the inductance value when one side is broken and the inductance value when not broken is 32.9 nH (= 69.7-36.8 nH) or more. One-end disconnection can be detected from the measured inductance value.

Next, it will be described that it is possible to determine whether or not one-side disconnection has occurred in the multiple wiring pattern even in consideration of variations (measurement errors) of measured values when the inductance is repeatedly measured.

The inductance value of the multiple wiring pattern was measured by the four-terminal pair method described with reference to FIG. 2 using the frequency of the alternating current output from the alternating signal source 17 as a parameter. The configuration of the measured multiple wiring pattern is different from the configuration of the multiple wiring pattern used in the calculation of FIG. The frequencies used for the measurement were five types of 1 kHz, 10 kHz, 100 kHz, 1 MHz and 10 MHz, and the inductance was measured three times for each frequency.

FIG. 4 (a) shows the measurement result, and FIG. 4 (b) shows the average value, the maximum value and the minimum value of the inductance calculated based on the measurement result. In addition, regarding the maximum value and the minimum value, the deviation from the average value is shown in parentheses as a change rate. As shown in FIG. 4 (b), the change rate of the inductance value obtained by the above measurement was 4% at maximum.

In the calculation example shown in FIG. 3, a case will be considered in which the average value (53.3 nH) of the lower limit value of the inductance at the time of one-side disconnection and the upper limit value of the inductance at the non-disconnection is used as the conduction determination threshold. At this time, the difference (Δ / 2) between the lower limit value of the inductance at the time of one-side disconnection and the threshold value for conduction determination and the difference (Δ / 2) between the upper limit value of the inductance and the threshold value for conduction determination at non-disconnection are either Also corresponds to a change rate of about 20% or more. Therefore, it can be said that the rate of change (maximum 4%) of the inductance value by repeated measurement is sufficiently lower than the difference Δ of the inductance value. Therefore, even if the measurement error is taken into consideration, it is possible to detect the one-side disconnection from the measured inductance value.

As described above, according to the present embodiment, it is possible to detect the disconnection of the multiple wiring pattern even at the measurement frequency of 1 kHz at which the change rate of the inductance value is the largest among the measurement frequencies of 1 kHz to 10 MHz. Since the inductance meter 16 tends to be more expensive as the measurement frequency is higher, the measurement at a relatively low frequency can reduce the cost of continuity check of multiple wiring patterns.

Next, a method of determining the threshold value for conduction determination will be specifically described.

First, the inductance value at the time of disconnection and the inductance value at the time of non-disconnection are measured for multiple wiring patterns of which dimensions are known (preferably, multiple wiring patterns fabricated according to the designed dimensions). In addition, you may use the calculated value obtained by electromagnetic field simulation etc. as these inductance values.

Next, as described above, the dimensional variation is added to the inductance value to obtain the possible range of the inductance value at the time of disconnection and the possible range of the inductance value at the time of non-disconnection. Then, a value smaller than the lower limit value of the inductance at the time of disconnection and larger than the upper limit value of the inductance at the time of non-disconnection is taken as a threshold value for conduction determination. The average value of the inductance value at the time of disconnection and the inductance value at the time of non-disconnection may be used as the threshold value for conduction determination without considering the dimensional variation.

Further, the present invention can be applied even if the number of wires forming the multiple wiring pattern is three or more. For example, it is assumed that the number of wires electrically connecting the first terminal and the second terminal is n, and the inductance value of each wire is the same (L). In this case, the combined inductance when all the wires are not disconnected is L / n, and the combined inductance when one wire is disconnected is L / (n-1). Therefore, a value larger than L / n and smaller than L / (n-1) may be used as the threshold for conduction determination. Preferably, the average value of these combined inductances, {(2 n -1) / 2 n (n-1)} L, is used as the threshold for conduction determination.

As described above, in the present embodiment, the inductance value of the multiple wiring pattern is measured using a four-terminal pair method at a measurement frequency of 1 kHz to 10 MHz, and the measured inductance value is compared with a predetermined conduction determination threshold. . As a result, disconnection of the multiple wiring pattern can be reliably detected even in consideration of variations in wiring width and thickness and measurement errors.

Also, the sensitivity to changes in wire length is generally higher for inductance than for DC resistance. For this reason, according to this embodiment, it is possible to detect the disconnection with high accuracy as compared with the pin contact method.

Furthermore, by using a relatively low measurement frequency as described above, the inductance measurement unit (inductance meter) can be manufactured at low cost compared to a TDR oscilloscope or the like. As a result, it is possible to reduce the cost of the continuity inspection of the multiple wiring pattern.

Second Embodiment
Next, a continuity inspection device 100A according to a second embodiment will be described using FIG. One of the differences between the second embodiment and the first embodiment is that the continuity inspection device 100A includes the resistance measurement unit 150. The differences from the first embodiment will be mainly described below.

In addition to the inductance measuring unit 110, the conduction determining unit 120, the storage unit 130, and the display unit 140, the continuity inspection apparatus 100A includes a resistance measuring unit 150 that measures a resistance value between the terminal 5 and the terminal 6.

More specifically, resistance measuring unit 150 includes a DC current source for causing DC current (I) to flow in a multiple wiring pattern, and a DC voltmeter for measuring a voltage (V) generated between terminals 5 and 6. By calculating the ratio of the current to the current (V / I), the DC resistance between terminals of the multiple wiring pattern can be obtained.

The conduction determination unit 120 compares the resistance value measured by the resistance measurement unit 150 with a predetermined determination threshold (the open determination threshold). The open determination threshold is set to a sufficiently large value of about several MΩ. As a result, if the resistance value is larger than the threshold value for open determination, it is determined that all the wires forming the multiple wiring pattern are disconnected. In this case, the continuity test using the inductance value described above is not performed, and the printed wiring board to be tested is determined to be a defective product. On the other hand, if the resistance value is smaller than the open determination threshold value, the continuity test using the inductance value described in the first embodiment is performed.

In addition to the determination of the presence or absence of the disconnection, the conduction determination unit 120 may determine the presence or absence of the short circuit. That is, the resistance value measured by the resistance measurement unit 150 is compared with a predetermined determination threshold (short determination threshold). The short determination threshold is set to a sufficiently small value of about several ohms. If the resistance value is smaller than the short determination threshold value, it may be determined that a short circuit has occurred in the multiple wiring pattern (such as a portion other than the first and second wires).

The continuity inspection method according to the second embodiment will be described with reference to the flowchart of FIG.

(1) First, the resistance measuring unit 150 measures the resistance value between the terminals 5 and 6 of the multiple wiring pattern as described above (step S11).

(2) The conduction determining unit 120 compares the resistance value with the threshold for open determination, and determines whether all the wires forming the multiple wiring pattern are disconnected (step S12). If it is determined that all the wirings are disconnected, it is determined that the printed wiring board to be inspected is a defective product (step S13). If not, the process proceeds to step S14.

(3) The inductance measuring unit 110 measures an inductance value between the terminals 5 and 6 of the multiple wiring pattern using the four-terminal pair method or the like (step S14).

(4) The continuity determining unit 120 compares the inductance value with the threshold for continuity determination, and determines whether or not a disconnection occurs in the multiple wiring pattern (step S15). If it is determined that disconnection does not occur in the multiple wiring pattern, the printed wiring board to be inspected is determined to be a normal product (step S16), and otherwise determined to be a defective product ( Step S13).

As described above, in the second embodiment, before conducting the continuity test based on the inductance value described in the first embodiment, the resistance value is measured, and it is determined whether or not all the wires forming the multiple wiring pattern are disconnected. Determine As a result, the number of times of inductance measurement that requires relatively high accuracy threshold setting can be reduced, and the continuity inspection of the multiple wiring pattern can be performed more efficiently.

In addition, since a test is performed on a plurality of multiple wiring patterns in the actual continuity test, the measurement of the resistance value and the measurement of the inductance value may be performed in parallel. For example, when it is determined that the resistance value is measured for a certain multiple wiring pattern and it is determined to be normal and the inductance value is measured, the resistance value of the other multiple wiring pattern is measured before the measurement of the inductance value is completed. You may go.

Although one skilled in the art may conceive of additional effects and various modifications of the present invention based on the above description, the aspects of the present invention are not limited to the individual embodiments described above. . Various additions, modifications and partial deletions are possible without departing from the conceptual idea and spirit of the present invention derived from the contents defined in the claims and the equivalents thereof.

1, 51 Double-sided Printed

Wiring Board

2, 52 Insulating

Substrates

3A, 3B, 53A,

53B Conductor Pattern

4, 7, 54, 57

Wiring

5, 6, 8, 9, 5, 55, 56, 59

Terminal

10, 11, 60 , 61 through

vias

12, 13 Kelvin probes 12a, 12b, 13a, 13b probe pins 16 inductance meters 17 AC signal sources 18 AC ammeters 19

AC voltmeters

21, 22, 23, 24

coaxial cables

21a, 22a, 23a,

24a Center conductor

21b, 22b, 23b, 24b External conductor (shield part)
25

Conductor

100, 100A Continuity inspection device 110 Inductance measurement unit 120 Conductivity determination unit 130 Storage unit 140 Display unit 150 Resistance measurement unit

Claims

A continuity inspection apparatus for conducting continuity inspection of a multiple wiring pattern having a first terminal and a second terminal and having a plurality of wirings electrically connecting the first and second terminals,
An inductance measurement unit that measures an inductance value between the first terminal and the second terminal;
The inductance value is compared with the threshold value for continuity determination, and if the inductance value is larger than the threshold value for continuity determination, it is determined that disconnection has occurred in the multiple wiring pattern, otherwise disconnection has occurred. A continuity determination unit that determines that there is no
A continuity inspection apparatus comprising:
The conduction determination threshold is
It is smaller than the disconnection inductance value which is an inductance value between the first terminal and the second terminal when disconnection occurs in the multiple wiring pattern, and no disconnection occurs in the multiple wiring pattern. The continuity inspection device according to claim 1, wherein the value is larger than a non-breaking inductance value which is an inductance value between the first terminal and the second terminal at the time.
The disconnection inductance value is a lower limit value of a range that can be taken by the inductance value at the time of disconnection due to the dimensional variation of the multiple wiring pattern, and the non-discontinuous inductance value is an inductance value at the time of non disconnection due to the dimensional variation of the multiple wiring pattern. The continuity inspection device according to claim 2, wherein the upper limit value of the range which can be taken is.
The continuity check device according to claim 2, wherein the threshold value for continuity determination is an average value of the open circuit inductance value and the non-open circuit inductance value.
The device further includes a resistance measurement unit that measures a resistance value between the first terminal and the second terminal,
The conduction determination unit compares the resistance value with the threshold value for open determination, and determines that all the plurality of wires are disconnected if the resistance value is larger than the threshold value for open determination, and the inductance value The continuity inspection device according to claim 2, wherein the continuity inspection using the above is not performed.
The conduction determination unit compares the resistance value with a short determination threshold, and determines that a short occurs in the multiple wiring pattern if the resistance value is smaller than the short determination threshold. The continuity inspection device according to claim 5.
The inductance measuring unit
An alternating current signal source that causes an alternating current for measurement to flow through the first terminal of the multiple wiring pattern;
An alternating current ammeter measuring the alternating current flowing out of the second terminal;
An alternating current voltmeter measuring a voltage between the first terminal and the second terminal;
With an inductance meter having
A first coaxial cable having a central conductor electrically connected to the output terminal of the alternating current signal source, and an external conductor electrically connected to the input terminal of the alternating current signal source;
A second coaxial cable having a central conductor electrically connected to the input terminal of the alternating current ammeter, and an external conductor electrically connected to the output terminal of the alternating current meter;
A third coaxial cable having a central conductor electrically connected to one terminal of the AC voltmeter, and an outer conductor electrically connected to an outer conductor of the first coaxial cable;
It has a center conductor electrically connected to the other terminal of the AC voltmeter, and an outer conductor electrically connected to the outer conductor of the second coaxial cable and the outer conductor of the third coaxial cable. A fourth coaxial cable,
A first probe pin electrically connected to the central conductor of the first coaxial cable and capable of being in contact with the first terminal;
A second probe pin electrically connected to the central conductor of the second coaxial cable and capable of being in contact with the second terminal;
A third probe pin electrically connected to the center conductor of the third coaxial cable and capable of being in contact with the first terminal;
A fourth probe pin electrically connected to the center conductor of the fourth coaxial cable and capable of being in contact with the second terminal;
The continuity inspection device according to claim 1, comprising:
The continuity inspection device according to claim 7, wherein the frequency of the alternating current is in the range of 1 kHz to 10 MHz.
The device further includes a resistance measurement unit that measures a resistance value between the first terminal and the second terminal,
The conduction determination unit compares the resistance value with the threshold value for open determination, and determines that all the plurality of wires are disconnected if the resistance value is larger than the threshold value for open determination, and the inductance value The continuity inspection apparatus according to claim 1, wherein the continuity inspection using the above is not performed.
The conduction determination unit compares the resistance value with a short determination threshold, and determines that a short occurs in the multiple wiring pattern if the resistance value is smaller than the short determination threshold. The continuity inspection device according to claim 9.
A continuity inspection method for conducting a continuity inspection of a multiple wiring pattern having a first terminal and a second terminal and having a plurality of wirings electrically connecting the first and second terminals,
Measuring an inductance value between the first terminal and the second terminal;
The inductance value is compared with the threshold value for continuity determination, and if the inductance value is larger than the threshold value for continuity determination, it is determined that disconnection has occurred in the multiple wiring pattern, otherwise disconnection has occurred. Determined not to,
A continuity inspection method characterized in that.
It is smaller than the disconnection inductance value which is an inductance value between the first terminal and the second terminal when disconnection occurs in the multiple wiring pattern, and no disconnection occurs in the multiple wiring pattern. The continuity inspection method according to claim 11, wherein a value larger than a non-breaking inductance value which is an inductance value between the first terminal and the second terminal at the time of use is used as the threshold value for the conduction determination. .
The lower limit value of the range which can be taken by the inductance value at the time of disconnection due to the dimensional variation of the multiple wiring pattern is used as the disconnection inductance value, and the inductance value at the time of non disconnection is used as the non-disconnection inductance value. The continuity inspection method according to claim 12, wherein an upper limit value of a range which can be taken is used.
The continuity inspection apparatus according to claim 12, wherein an average value of the disconnection inductance value and the non-interconnection inductance value is used as the conduction determination threshold value.
Before measuring the inductance value, the resistance value between the first terminal and the second terminal is measured, the resistance value is compared with the threshold value for open determination, and the resistance value is the threshold value for open determination. 13. The continuity test method according to claim 12, wherein if it is larger, it is determined that all of the plurality of wires are disconnected, and a continuity test using the inductance value is not performed.
The method according to claim 15, wherein the resistance value is compared with the short determination threshold, and if the resistance is smaller than the short determination threshold, it is determined that a short occurs in the multiple wiring pattern. Conduction inspection method described.
The continuity test method according to claim 11, wherein the measurement of the inductance value is performed by a four-terminal pair method.
The method according to claim 17, wherein the frequency of the alternating current used for measuring the inductance value is in the range of 1 kHz to 10 MHz.
Before measuring the inductance value, the resistance value between the first terminal and the second terminal is measured, the resistance value is compared with the threshold value for open determination, and the resistance value is the threshold value for open determination. 12. The continuity test method according to claim 11, wherein if it is larger, it is determined that all the plurality of wires are disconnected, and a continuity test using the inductance value is not performed.
20. The apparatus according to claim 19, wherein the resistance value is compared with the short determination threshold, and if the resistance is smaller than the short determination threshold, it is determined that a short occurs in the multiple wiring pattern. Conduction inspection method described.