JP2003014807A - Measuring method for capacitance as well as method and apparatus for inspection of circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method in which the capacitance of a pattern is measured in a short time and with satisfactory efficiency. SOLUTION: In the method in which a probe is brought into contact with each pattern so as to measure an interelectrode capacitance across each pattern and an electrode, a process (Step 30) in which the disconnection of the pattern is inspected is executed, a process (Step 32) in which a first interelectrode capacitance is measured regarding each pattern whose disconnection is not detected in a state that the probe is separated, a process (Step 33) in which the probe is brought into contact with the pattern so as to measure a second interelectrode capacitance and a process (Step 34) in which the difference capacitance between both interelectrode capacitances is stored as interelectrode capacitances with reference to the pattern are executed, a process (Step 36) wherein a group of patterns to which the stored interelectrode capacitances are brought close is detected, and a process (Step 37) in which a short circuit across the patterns belonging to the group is inspected are executed. The interelectrode capacitance stored by excluding the interelectrode capacitance of the patterns whose short circuit is detected is regarded as a normal interelectrode capacitance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance measuring method for measuring the capacitance between counter electrodes between a plurality of conductor patterns and a reference electrode on a circuit board to be measured, and the measured capacitance between counter electrodes. The present invention relates to a circuit board inspection method and a circuit board inspection device for inspecting a circuit board based on a capacity.

[0002]

2. Description of the Related Art FIG.
A capacitance measuring method for measuring the capacitance according to the procedure shown in FIG. This capacitance measuring method is carried out, for example, in a circuit board inspection process by the circuit board inspection device 41 shown in FIG. In this case, the circuit board inspection device 41
Is an electrode portion 2 having an electrode 2b to which an insulating film 2a is attached, inspection probes 3 and 4, moving mechanisms 5a and 5b,
The control unit 46, the RAM 7 and the ROM 8 are provided. On the other hand, as shown in FIG. 3, the circuit board P to be inspected has a plurality of conductor patterns CP1, CP2, ... On the surface of the glass epoxy base material (hereinafter, also referred to as “conductor pattern CP” unless otherwise distinguished). ) Is formed and configured. Further, as shown in the figure, lands are formed at each end point of each conductor pattern CP, and these lands are referred to as measurement points TP1, TP2 ,. Say)
Function as.

Next, the operation of the circuit board inspection device 41 will be described with reference to FIGS. First, the circuit board P is placed on the electrode 2b in the electrode portion 2 with the surface on which the conductor pattern CP is formed facing upward. Next, the controller 46 controls the moving mechanisms 5a and 5b to control the probe fixtures 3a and 4a.
The test probes 3 and 4 attached to the measurement points TP1 and TP on the conductor pattern CP1 of the circuit board P.
2 are contacted with each other (step 50). Then, the control unit 46 sequentially outputs the AC voltage as the inspection signal, so that the inter-electrode capacitance CTC1 between the conductor pattern CP1 and the electrode 2b at the measurement point TP1 and the conductor pattern CP1 at the measurement point TP2. Electrostatic capacitance CTC2 between the counter electrode and the electrode 2b is provisionally measured by autoranging. In this case, in order to accurately measure the capacitance between the counter electrodes, it is necessary to select a measurement range suitable for the measured capacitance between the counter electrodes. That is, for example, it is difficult to accurately measure the capacitance between the counter electrodes which reaches near the upper limit value or the lower limit value of the measurement range in the measurement range. Therefore, a measurement range suitable for each tentatively measured capacitance between counter electrodes CTC1 and CTC2 (hereinafter, also referred to as "counterelectrode capacitance CTC" when no distinction is made) is selected and set (step 51). . More specifically,
For example, set the capacitance between counter electrodes CTC1 to full scale 20p.
When 3pF is obtained by tentative measurement in the F measurement range, 3p
Full scale 10p most suitable for measuring F accurately
Select and set the F measurement range.

Next, the control unit 46 controls the moving mechanisms 5a and 5b.
Control unit to move the inspection probes 3 and 4 upward to separate them slightly from the measurement points TP1 and TP2, and sequentially output an AC voltage as a test signal in this state, thereby stray capacitance CS1 at the measurement point TP1. , And the stray capacitance CS2 at the measurement point TP2 are measured in the set measurement ranges and stored in the RAM 7 (step 52).
By the measurement process in step 52, the stray capacitance caused by the inspection probes 3 and 4 and the probe fixtures 3a and 4a is measured. Next, the control unit 46 causes the moving mechanism 5a,
5b is controlled to bring the inspection probes 3 and 4 into contact with the measurement points TP1 and TP2 again, and the alternating voltage as the inspection signal is sequentially output, so that between the conductor pattern CP1 and the electrode 2b at the measurement point TP1. The inter-electrode capacitance CPR1 and the inter-electrode capacitance CPR2 between the conductor pattern CP1 and the electrode 2b at the measurement point TP2 (hereinafter, also referred to as “inter-electrode capacitance CPR” when not distinguished) are respectively set. The measurement is performed in the measurement range set in step 51 (step 53). Then
The control unit 46 controls the measured measurement points TP1 and TP2.
From the electrostatic capacitances CPR1 and CPR2 between the counter electrodes to the stray capacitances CS1 and CS2 at the measurement points TP1 and TP2, respectively.
(Hereinafter, when no distinction is made, it is also referred to as "stray capacitance CS"), and this differential capacitance is stored in the RAM7 as the regular interelectrode capacitances CTP1 and CTP2 at the respective measurement points TP1 and TP2 that eliminate the influence of the stray capacitance. It is stored (step 54). The control unit 46 uses the conductor pattern CP.
The above steps 50 to 54 are carried out for the remaining measurement point TP3 in 1 as well, and the capacitance between counter electrodes CTP3
Is calculated and stored in the RAM 7.

The control unit 46 controls all the measurement points TP.
It is determined whether or not the capacitance CTP between the counter electrodes has been measured (step 55), and when there is an unmeasured measurement point, the above steps 50 to 54 are repeated to define another conductor pattern CP. The measured capacitance CTP between the counter electrodes at each measured point TP is sequentially measured and RAM
Store in 7. Next, the control unit 46, in step 55, the capacitance C between the counter electrodes of all the measurement points TP.
When it is determined that TP has been measured, each conductor pattern C is calculated based on the capacitance CTP between the counter electrodes stored in the RAM 7.
For each P, each measurement point TP in the conductor pattern CP
The electrostatic capacitances CTP and CTP between the counter electrodes are compared with each other, and it is determined whether or not there are conductor patterns CP having different electrostatic capacitances CTP between the counter electrodes (step 56). In this case,
When there is no disconnection point like the conductor pattern CP2 shown in FIG. 3, the capacitances CTP4 to CTP6 between the counter electrodes at the measurement points TP4 to TP6 have the same or similar capacitance values. On the other hand, when the disconnection point B exists like the conductor pattern CP1, the measurement point TP2
The electrostatic capacitance CTP2 between the counter electrodes at is different from the electrostatic capacitances CTP1 and CTP3 between the counter electrodes at the other measurement points TP1 and TP3, which should have essentially the same capacitance. Therefore, the control unit 46, in step 56,
When the capacitance CTP between the counter electrodes at each measurement point TP in the same conductor pattern CP is different from each other, a disconnection inspection is performed on this conductor pattern CP to identify the disconnection point (step 57). Specifically, the moving mechanisms 5a and 5b are controlled to bring one of the inspection probes 3 into contact with a measurement point TP whose electrostatic capacitance CTP between its counter electrodes is different from that of the other electrostatic capacitance CTP between its counter electrodes, and By measuring the resistance value between the inspection probes 3 and 4 while sequentially contacting the inspection probe 4 with the remaining measurement points TP, the disconnection point is specified and the disconnection point information is stored in the RAM 7.

Next, in step 56, when there is no conductor pattern CP having a different inter-electrode capacitance CTP, and when the disconnection inspection in step 57 is completed, the control unit 46 causes each counter electrode stored in the RAM 7 to be stored. Based on the inter-electrode capacitance CTP, the presence / absence of a group of conductor patterns CP whose inter-electrode capacitances CTP are similar to each other is detected (step 58). At this time, when a group of conductor patterns CP whose counter electrode electrostatic capacitances CTP are close to each other is detected, there is a possibility that a short circuit portion A as shown in FIG. 3 exists between the conductor patterns CP and CP. . Therefore, the control unit 46
Performs a short-circuit inspection between the conductor patterns CP and CP in which the electrostatic capacitances CTP between the counter electrodes are close to each other (step 5).
9). Specifically, by controlling the moving mechanisms 5a and 5b, the inspection probes 3 and 4 are respectively brought into contact with the pair of conductor patterns CP and CP whose electrostatic capacitances CTP between the counter electrodes are close to each other, and both conductor patterns CP and CP are The presence or absence of a short-circuit point is specified by measuring the resistance value between them. Next, when there is a short-circuited portion, the short-circuited portion information (information regarding the presence or absence of a short-circuit) is stored in the RAM 7. On the other hand, in step 58, when the group of the conductor patterns CP having the electrostatic capacitances CTP between the counter electrodes that are close to each other is not detected, the electrostatic capacitance measuring process is ended.

According to the capacitance measuring method by the circuit board inspecting device 41, the broken conductor pattern CP and the broken portion of the broken conductor pattern CP are detected and short-circuited to another conductor pattern CP. Conductor pattern C
While detecting P, it is possible to measure and store the capacitance CTP between the counter electrodes for the normal conductor pattern CP.

[0008]

However, the conventional capacitance measuring method has the following problems. That is, in the conventional capacitance measuring method, all measurement points TP
In order to select an appropriate measurement range, the inter-electrode capacitance CTC is measured, then the stray capacitance CS is measured, and then the inter-electrode capacitance CPR is further measured to determine the normal inter-electrode capacitance. It is necessary to calculate the electrostatic capacitance CTP. Therefore, at each measurement point TP, it is necessary to move the inspection probe 3 (or 4) toward and away from the measurement point TP (up and down movement) at least twice. In this case, the vertical movement of the inspection probe 3 (or 4) requires a somewhat long tact time in order to control the acceleration and the brake of the inspection probe 3. Therefore, all measurement points TP on all conductor patterns CP
There is a problem that it takes an enormous amount of time to measure the capacitance C TP between the counter electrodes of the above. Further, when the conductor pattern CP has a disconnection, the measurement of the capacitance CTP between the counter electrodes for each measurement point TP on the conductor pattern CP becomes useless. Therefore, there is a problem that the measurement efficiency is lowered.

The present invention has been made in view of the above problems, and its main object is to provide a capacitance measuring method capable of efficiently measuring the capacitance of a conductor pattern in a short time. Another object is to provide a circuit board inspecting method and a circuit board inspecting apparatus capable of efficiently inspecting a circuit board in a short time.

[0010]

In order to achieve the above object, the capacitance measuring method according to claim 1 is such that a contact type probe is brought into contact with a plurality of conductor patterns on a circuit board to be measured one after another. A capacitance measuring method for measuring a capacitance between counter electrodes between a pattern and a reference electrode, wherein after performing a disconnection inspection process for inspecting a disconnection of each of the conductor patterns, a disconnection occurs in the disconnection inspection process. A first inter-electrode capacitance between the probe and the reference electrode is measured by arranging the probe in a state of being separated from the conductor pattern for each of the conductor patterns not detected. And a second inter-electrode electrostatic capacitance between the conductor pattern and the reference electrode by contacting one measurement point on the conductor pattern from a state where the probe is separated. A second capacitance measuring process for measuring an amount, and a difference capacitance between the measured second capacitance between the counter electrodes and the first capacitance between the counter electrodes is measured between the counter electrodes corresponding to the conductor pattern. A detection process of executing a measurement result saving process of saving as electrostatic capacitance, and detecting a group of the conductor patterns in which the stored inter-electrode capacitances are close to each other, and the conductor pattern belonging to the detected group A short-circuit inspection process for inspecting a short circuit between the electrodes is performed, and the stored inter-electrode capacitance is excluded except the inter-electrode capacitance for the conductor pattern in which a short circuit is detected by the short-circuit inspection process. It is characterized in that it is a normal capacitance between the counter electrodes.

According to a second aspect of the present invention, there is provided a circuit board inspecting method, in which a contact-type probe is arranged for each conductor pattern on a circuit board to be inspected so as to be spaced from the conductor pattern, and the probe and the reference electrode. A first capacitance measuring process for measuring a first inter-electrode capacitance between the conductor pattern and the reference by bringing the probe into contact with one measurement point on the conductor pattern from a separated state. A second measuring capacitance between a second counter electrode and the electrode;
And the difference capacitance between the measured second capacitance between the counter electrodes and the first capacitance between the counter electrodes is stored as the capacitance between the counter electrodes corresponding to the conductor pattern. A measurement result storage process is executed, and the stored pairs of the circuit board to be inspected are used with the respective regular inter-electrode capacitances measured by the capacitance measurement method according to claim 1 as reference data. When the inter-electrode capacitance is within a predetermined range with respect to the corresponding reference data, it is determined that the conductor pattern is not broken or short-circuited.

According to a third aspect of the present invention, there is provided a circuit board inspecting apparatus which comprises a contact-type probe and each conductor pattern and a reference electrode in a state where the probe is in contact with each of a plurality of conductor patterns on a circuit board to be measured. A circuit board inspection apparatus comprising: a control unit that measures an inter-counter electrode electrostatic capacitance between and a control unit that inspects a circuit board to be inspected based on the measured inter-electrode electrostatic capacitance, wherein the control unit is After performing the disconnection inspection process for inspecting the disconnection of each of the conductor patterns,
For each of the conductor patterns for which no disconnection was detected in the disconnection inspection process, the probe is arranged in a state of being separated from the conductor pattern, and the first counter electrode between the probe and the reference electrode is arranged. A first capacitance measurement process for measuring capacitance, and a second counter electrode between the conductor pattern and the reference electrode by bringing the probe into contact with one measurement point on the conductor pattern from a separated state. A second capacitance measuring process for measuring an inter-electrode capacitance, and a difference capacitance between the measured second inter-electrode capacitance and the first inter-electrode capacitance, which corresponds to the conductor pattern. A detection process of performing a measurement result storage process of storing the capacitance between the counter electrodes and detecting a group of the conductor patterns in which the stored capacitances between the counter electrodes are close to each other, and the detected group. Belongs to Performing a short-circuit inspection process for inspecting a short circuit between the conductor patterns, and between the stored counter electrodes except for the inter-electrode capacitance of the conductor pattern in which a short circuit is detected by the short-circuit inspection process. It is characterized in that the electrostatic capacitance is a normal electrostatic capacitance between the counter electrodes.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a capacitance measuring method, a circuit board inspecting method and a circuit board inspecting apparatus according to the present invention will be described below with reference to the accompanying drawings. The same components as those of the conventional circuit board inspecting device 41 and the circuit board P to be inspected are designated by the same reference numerals, and a duplicate description will be omitted.

First, the structure of the circuit board inspection apparatus 1 to which the present invention is applied will be described with reference to FIG.

As shown in FIG. 1, the circuit board inspection apparatus 1
Is an electrode unit 2, inspection probes 3 and 4, a moving mechanism 5a,
5b, a control unit 6, a RAM 7 and a ROM 8 are provided. The electrode part 2 has an insulating film 2a on its surface.
It has a flat plate-shaped electrode 2b to which is attached so that a circuit board P to be inspected can be placed. Inspection probe 3,
4 is a contact type probe, which is a probe fixture 3a,
It is arranged above the electrode unit 2 in a state of being attached to the moving mechanisms 5a and 5b via the 4a. The control unit 6 includes a circuit board P using the electrode unit 2 and the inspection probes 3 and 4.
And the drive control of the moving mechanisms 5a and 5b. The RAM 7 stores the position data of the measurement point TP for each conductor pattern CP, the measured stray capacitance CS, the measured capacitance between counter electrodes CTP, the information on the detected disconnection point and short-circuited point, the calculation result of the control unit 6, and the like. Store temporarily. The ROM 8 stores the operation program of the control unit 6.

Next, the operation of the circuit board inspection apparatus 1 will be described with reference to FIG. In addition, about the same operation | movement as the circuit board inspection apparatus 41, that effect is described and the overlapping description is abbreviate | omitted.

First, the circuit board P is placed on the electrode portion 2 with the surface on which the conductor patterns CP1 and CP2 are formed facing upward.

Next, the control section 6 starts the capacitance measuring process shown in FIG. In this process, the control unit 6 controls the moving mechanisms 5a and 5b to move the inspection probes 3 and 4 attached to the probe fixtures 3a and 4a to above the conductor pattern CP1 of the circuit board P, and Pattern C
A disconnection inspection is performed on P1 (step 30: disconnection inspection processing). Specifically, the control unit 6 brings the inspection probe 3 into contact with the measurement point TP1 shown in FIG. 3, and simultaneously brings the inspection probe 4 into contact with the measurement point TP2 and the measurement point TP3 in order to make the measurement point TP1,
By outputting an AC voltage (or DC voltage) as a test signal between TP2 and between measurement points TP1 and TP3, the resistance value between each measurement point TP and TP is measured to inspect the conductor pattern CP1 for disconnection.

When it is determined in step 30 that the disconnection point B as shown in FIG. 3 does not exist in the conductor pattern CP1, the control section 6 controls the moving mechanisms 5a and 5b to determine which of the inspection probes 3 and 4 is to be used. One of the inspection probes (as an example, the inspection probe 4) is moved upward, and one measurement point TP (as an example, the measurement point TP1) is maintained in contact with the other inspection probe (as an example, the inspection probe 3). Then, by outputting an AC voltage as an inspection signal through the inspection probe 3, the provisional inter-electrode capacitance CTC1 between the conductor pattern CP1 and the electrode 2b is provisionally measured. Subsequently, the control unit 6 determines the conductor pattern C based on the measured capacitance CTC1 between the counter electrodes.
A measurement range suitable for the capacitance measurement at the measurement point TP of P1 is selected and set (step 31). Next, the control unit 6 controls the moving mechanism 5a to move the inspection probe 3 slightly away (upward) from the measurement point TP1, and in this state, outputs an AC voltage as the inspection signal, so that the measurement point TP1. The stray capacitance (corresponding to the first capacitance between the counter electrodes in the present invention) CS1 is measured and stored in the RAM 7 (step 32: first capacitance measurement process). Thereby, the stray capacitance due to the inspection probe 3 and the probe fixture 3a at that position is measured.

Next, the control section 46 controls the moving mechanism 5a to bring the inspection probe 3 into contact with the measurement point TP1 again, and outputs an AC voltage as an inspection signal, thereby the conductor pattern at the measurement point TP1. The capacitance between counter electrodes between CP1 and the electrode 2b (corresponding to the second capacitance between counter electrodes in the present invention) CPR1 is measured using the measurement range set in step 31 (step 3).
3: Second capacity measurement process). Next, the control unit 46 subtracts the stray capacitance CS1 from the inter-electrode electrostatic capacitance CPR1 and subtracts the difference (CPR1-CS1) from the regular inter-electrode electrostatic capacitance C for the conductor pattern CP1 in which the influence of the stray capacitance is eliminated.
It is stored (saved) in RAM 7 as CP1 (step 3)
4: measurement result storage process). After that, the control unit 46 controls the inter-counterelectrode capacitance CCP for all the conductor patterns CP.
1, CCP2 ··· (hereinafter, when no distinction is made, also referred to as “counter electrode capacitance CCP”) is determined (step 35), and the above steps are performed for other conductor patterns CP as well. 30 to 34 are carried out to sequentially measure the electrostatic capacitance CCp between the counter electrodes and store it in the RAM 7. In this case, in the disconnection inspection in step 30, when it is determined that the disconnection point exists in the conductor pattern CP, the control unit 6
Stores the disconnection location information in the RAM 7 and does not perform steps 31 to 34 for this conductor pattern CP,
Go to step 35. When there is at least one conductor pattern CP that is determined to have a disconnection point in the disconnection inspection of step 30, all the measurement processing for that circuit board P is completed and this electrostatic discharge is performed on another circuit board P. The capacity measurement process may be executed.

Next, when the control section 6 determines in step 35 that the inter-electrode capacitances CCP of all the conductor patterns CP have been measured, the control section 6 is based on the inter-electrode capacitances CCP stored in the RAM 7. , The presence / absence of a group of conductor patterns CP, CP, ... whose electrostatic capacitances CCP between counter electrodes are similar to each other is detected (step 36: detection processing). In this process, when a group of conductor patterns CP in which the capacitances CCp between the counter electrodes are close to each other is detected, between the conductor patterns CP, CP (or three or more conductor patterns C).
For example, there is a possibility that a short circuit portion A as shown in FIG. 3 exists between (P, CP, CP). Therefore, the control unit 6
Inspects a short circuit between the conductor patterns CP belonging to the detected group, CP (step 37: short circuit inspection process). Specifically, by controlling the moving mechanisms 5a and 5b, the inspection probes 3 and 4 are brought into contact with the conductor patterns CP and CP having electrostatic capacitances CCP close to each other, and the resistance value between the conductor patterns is measured. By doing so, the presence or absence of the short-circuited portion is determined, and when the short-circuited portion exists, the portion is specified and the short-circuited portion information is stored in the RAM 7. on the other hand,
In step 36, when the group of the conductor patterns CP whose capacitances CCP between the counter electrodes are similar to each other is not detected, this capacitance measurement process is ended. By performing the above processing, the measurement of the inter-electrode capacitance CCP of the normal conductor pattern CP of the circuit board P is completed, and the circuit board inspection regarding the presence or absence of the disconnection point or the short circuit point on the circuit board is completed. Is completed.

Next, when inspecting the same type of circuit board P, the circuit board P to be inspected is first subjected to the conductor pattern CP1.
, CP2 is placed on the electrode portion 2 with the formation surface facing upward. Next, the control unit 6 measures the inter-electrode capacitance CPR in the capacitance measurement process shown in FIG. 1 (step 33), and measures the inter-electrode capacitance CPR measured in this step 33. Stray capacitance C for each conductor pattern CP that has been measured in advance by the above-described capacitance measurement process.
The calculation process of the inter-electrode capacitance CCP based on S (step 34) is repeatedly executed for each conductor pattern CP.
In this case, in the measurement process of the capacitance CPR between the counter electrodes (step 33), the capacitance CPR between the counter electrodes is measured in the same measurement range as that used in the capacitance measurement process. Further, for each of all the conductor patterns CP on the circuit board P, step 3 of the above-described capacitance measurement process.
The same measurement point TP as the measurement point TP measured in 3
The inter-electrode electrostatic capacitance CCP of is measured and stored in the RAM 7. Next, the control section 6 uses the inter-electrode capacitance CCCP already stored in the RAM 7 as reference data and stores the inter-electrode capacitance C stored for the circuit board P to be inspected.
When CP is within a predetermined range (for example, within ± 10%) with respect to the corresponding reference data, it is determined that the conductor pattern CP has no disconnection or short circuit (determination process).
By performing this determination process for all the conductor patterns CP, the circuit board inspection process for the circuit board P to be inspected is completed.

As described above, according to this capacitance measuring method, between the counter electrodes for selecting a measurement range suitable for measuring the capacitance between counter electrodes CCP for one conductor pattern CP. Capacitance between counter electrodes CCP can be measured only once by measuring capacitance CTC, measurement of stray capacitance CS, remeasurement of capacitance between counter electrodes CTP, and calculation of capacitance between counter electrodes CCP. Can be measured. Therefore, as compared with the conventional capacitance measuring method that requires performing each of the above processes once for each of the measurement points TP, all the capacitances between the counter electrodes CCP are extremely short. Can be measured. Specifically, ignoring the time required for the disconnection inspection process (step 30) that is completed in a relatively short time, and assuming that there are an average of four measurement points TP in one conductor pattern CP, the capacitance between the counter electrodes is The measurement time for CCP can be shortened to 1/4. Further, by performing a disconnection inspection process (step 30) on each conductor pattern CP prior to the measurement of the inter-electrode electrostatic capacitance CCP, the inter-electrode electrostatic capacitance for the conductor pattern CP in which the disconnection point exists. Useless measurement of CCP can be avoided. Therefore, the measurement efficiency can be improved accordingly. Furthermore, as a result of being able to measure the capacitance CCP between the counter electrodes in a short time, the circuit board P can be inspected in a short time, and thus the inspection cost for the circuit board P can be reduced.

The present invention is not limited to the configuration shown in the above-mentioned embodiment of the present invention. For example, in the embodiment of the present invention, the example in which the capacitance measuring method according to the present invention is applied to the inspection process of the circuit board inspecting device has been described, but it is applied to the capacitance measuring device that simply measures the capacitance. You can also do it. Further, in the embodiment of the present invention, an example of capacitance measurement using the electrode 2b of the electrode portion 2 as the reference electrode has been described. However, for example, a ground pattern or a power source having a large area in the circuit board P to be inspected. A pattern or the like can also be used as the reference electrode. Furthermore, the disconnection inspection process (step 30) for all the conductor patterns CP can be collectively performed prior to the measurement of the capacitance CCP between the counter electrodes (steps 31 to 34). Further, in the embodiment of the present invention, an example in which a measurement range suitable for measurement is selectively set in order to improve the measurement accuracy of the capacitance between counter electrodes CCP has been described, but the present invention is not limited to this. That is, the provisional measurement process of the capacitance CTC between the counter electrodes for selecting and setting the measurement range suitable for the measurement is omitted, and the measurement process on the measurement point TP described above (step 32:
The stray capacitance (first inter-electrode capacitance in the present invention) CS measured by the first capacitance measurement process and the inter-electrode capacitance measurement process between the conductor pattern CP and the electrode 2b thereof (step 33) : The counter electrode capacitance C based on the counter electrode capacitance (second counter electrode capacitance in the present invention) CPR measured by the second capacitance measurement process).
Of course, CP can be measured.

[0025]

As described above, according to the capacitance measuring method of the first aspect, the disconnection inspection of the conductor pattern is performed prior to the capacitance measurement at the measurement point on each conductor pattern. For one conductor pattern,
For example, the measurement process of the capacitance between the counter electrodes for selecting a measurement range suitable for measuring the capacitance between the counter electrodes,
The capacitance between the counter electrodes can be measured by performing the first measurement process, the second measurement process, and the measurement result storage process only once each. Therefore, compared to the conventional capacitance measurement method, which requires performing each of the above processes once for each measurement point, all capacitances between counter electrodes can be measured in an extremely short time. can do. Further, by performing a disconnection inspection process on each conductor pattern prior to measuring the capacitance between the counter electrodes, it is possible to avoid wasteful measurement of the capacitance between the counter electrodes for the conductor pattern having the disconnection point. Because you can,
The measurement efficiency can be improved.

According to the circuit board inspection method of the second aspect and the circuit board inspection apparatus of the third aspect, the capacitance between the counter electrodes can be measured in a short time, and as a result, the circuit board inspection for the circuit board can be performed in a short time. Therefore, the inspection cost for the circuit board can be sufficiently reduced.

[Brief description of drawings]

FIG. 1 is a circuit board inspection apparatus 1 according to an embodiment of the present invention.
5 is a flowchart showing a capacitance measurement process by the.

FIG. 2 is a configuration diagram showing configurations of a circuit board inspection device 1 and a conventional circuit board inspection device 41.

FIG. 3 is a top view of a circuit board P which is an example of an inspection target.

FIG. 4 is a flowchart showing a capacitance measurement process by a conventional circuit board inspection device 41.

[Explanation of symbols]

1 Circuit board inspection device 2 electrodes 3,4 Inspection probe 5a, 5b moving mechanism 6 control unit 7 RAM CP1, CP2 conductor pattern P circuit board TP1 to TP6 measurement points

Claims (3)

[Claims] 1. A capacitance measuring method in which a contact-type probe is sequentially brought into contact with a plurality of conductor patterns on a circuit board to be measured to measure an inter-electrode capacitance between each conductor pattern and a reference electrode. That is, after performing the disconnection inspection process for inspecting the disconnection of each of the conductor patterns, for each of the conductor patterns in which no disconnection was detected in the disconnection inspection process, the probe was separated from the conductor pattern. A first capacitance measuring process for arranging the probe in a state and measuring a first inter-electrode capacitance between the probe and the reference electrode; and one measurement on the conductor pattern from a state where the probe is separated. A second capacitance measurement process of contacting a point to measure a second inter-electrode capacitance between the conductor pattern and the reference electrode; and the measured second inter-electrode capacitance. And a measurement result storage process of storing a difference capacitance between the first and second counter-electrode capacitances as the counter-electrode capacitance corresponding to the conductor pattern, and storing the stored counter-electrode capacitances. A detection process of detecting a group of the conductor patterns that are close to each other and a short circuit inspection process of inspecting a short circuit between the conductor patterns belonging to the detected group are executed, and a short circuit is detected by the short circuit inspection process. The electrostatic capacitance measuring method, wherein the stored inter-electrode capacitance excluding the inter-electrode capacitance of the conductor pattern is set as the normal inter-electrode capacitance. 2. A first counter electrode between the probe and the reference electrode, wherein a contact-type probe is arranged in a state of being separated from the conductor pattern for each conductor pattern on a circuit board to be inspected. A first capacitance measuring process for measuring the electrostatic capacitance between the conductor pattern and the second pair between the conductor pattern and the reference electrode by bringing the probe into contact with one measurement point on the conductor pattern from a separated state. A second capacitance measuring process for measuring an inter-electrode capacitance and a differential capacitance between the measured second inter-electrode capacitance and the first inter-electrode capacitance correspond to the conductor pattern. The measurement result storage process of storing the capacitance between the counter electrodes is executed, and the inspection is performed by using the respective regular capacitance between the counter electrodes measured by the capacitance measuring method according to claim 1 as reference data. Target circuit board The circuit board inspection method is characterized in that when the stored capacitance between the counter electrodes is within a predetermined range with respect to the corresponding reference data, the conductor pattern is not broken or short-circuited. . 3. A contact-type probe and a counter electrode capacitance between each conductor pattern and a reference electrode in a state where the probe is in contact with each of a plurality of conductor patterns on a circuit board to be measured. A circuit board inspecting device comprising: a control unit that inspects a circuit board to be inspected based on the measured capacitance between the counter electrodes, and the control unit inspects a break in each of the conductor patterns. After performing the disconnection inspection process, for each of the conductor patterns for which no disconnection was detected in the disconnection inspection process, the probe and the reference electrode are arranged in a state of being separated from the conductor pattern. And a first capacitance measuring process for measuring the capacitance between the first counter electrodes between the two electrodes, and bringing the probe into contact with one measurement point on the conductor pattern from a separated state. Second capacitance measurement processing for measuring a second inter-electrode capacitance between the conductor pattern and the reference electrode, the measured second inter-electrode capacitance and the first counter electrode A measurement result storing process of storing a difference capacitance between the inter-electrode capacitance as the inter-electrode capacitance corresponding to the conductor pattern, and the stored inter-electrode capacitance is close to each other. A detection process for detecting a group of conductor patterns and a short circuit inspection process for inspecting a short circuit between the conductor patterns belonging to the detected group are executed, and the short circuit is detected by the short circuit inspection process. The circuit board inspecting device, wherein the stored inter-electrode capacitance excluding the inter-electrode capacitance is set as the normal inter-electrode capacitance.