JP4597236B2 - Circuit board inspection method and circuit board inspection apparatus - Google Patents

Description

The present invention relates to a circuit board inspection method and a circuit board inspection apparatus for inspecting the quality of a circuit board by conducting continuity inspection and insulation inspection on a plurality of conductor patterns on a circuit board to be inspected.

  In recent years, the density of conductor patterns on circuit boards has been increasing, and in order to automatically inspect such high-density circuit boards during mass production, it is necessary to absorb inspection data from non-defective circuit boards. For this reason, in the initial stage of mass production, it is necessary to select a good circuit board from a large number of circuit boards. At this time, conventionally, circuit boards are selected according to a conduction insulation inspection method described below.

In this conventional insulation continuity inspection method, first, the quality of the circuit board is inspected by a continuity inspection. In this case, as shown in FIG. 6, for example, when conductor patterns P1 to P5 (hereinafter referred to as “conductor pattern P” when not distinguished from each other) insulated from each other are formed on the circuit board PC, The conduction state between the terminal portions of each conductor pattern P is inspected. Specifically, for the conductor pattern P1, contact probes are brought into contact with the terminal portions P11 and P12, respectively, and the conduction resistance between both contact probes is measured. At this time, when the conduction resistance is less than the predetermined resistance value, it is determined that both terminal portions P11 and P12 are normally connected without disconnection, and when the resistance value is equal to or higher than the predetermined resistance value, there is a gap between both terminal portions P11 and P12. Judge that it is disconnected. In the same manner, the connection between all the two points (each between P11 and P13, between P11 and P14, between P12 and P13, between P12 and P14, and between P13 and P14) in each end portion P11 to P14 of the conductor pattern P1 is conducted. Perform inspection. Next, between the end portions P21 and P22 of the other conductor pattern P2, between the end portions P31 and P32 of the conductor pattern P3, between the end portions P41 to P44 of the conductor pattern P4, and between the end portions P51 and P52 of the conductor pattern P5. The above-described continuity test is executed. When it is determined that the conductor pattern P is normal in the continuity test for all the conductor patterns P, it is determined that the conductor pattern P is not disconnected. In this case, when the number of conductor patterns P is a value A and the number of terminal portions is a value B, the number of times of measurement N1 is expressed by the following equation (1).
N1 = (BA) (1) formula

Next, the quality of the circuit board is inspected by an insulation inspection. At this time, a contact-type probe is brought into contact with an arbitrary portion of each conductor pattern P, P, and the conduction resistance between both conductor patterns P is measured. At this time, when the conduction resistance is equal to or greater than the predetermined resistance value, it is determined that the two conductor patterns P are normally insulated without being short-circuited by a solder bridge or the like. It is determined that P and P are short-circuited. Combinations of all conductor patterns P and P (between P1 and P2, between P1 and P3, between P1 and P4, between P1 and P5, between P2 and P3, between P2 and P4, between P2 and P5, between P3 and P4 , P3-P5, P4-P5). When it is determined that the insulation inspection between all the conductor patterns P and P is normal and no disconnection occurs, the circuit board PC is determined to be a non-defective product. In this case, the number of times of measurement N2 is expressed by the following equation (2).
N2 = A (A-1) / 2 ... (2) formula

  However, at the start of mass production, the yield of high-density circuit board PC is extremely low, and there are many cases where, for example, 1000 non-defective circuit board PCs are provided. On the other hand, in the conventional circuit board inspection method, for example, 1000 independent conductor patterns P are formed on one circuit board PC, and three terminal portions are formed on each of the conductor patterns P on average. In this case, the total number of measurements N of the continuity test measurement number N1 and the insulation test measurement number N2 is an enormous number of about 500,000 times. Therefore, when about 0.1 second is required for the movement of the contact probe, the inspection time is about 13.9 hours. As a result, the conventional circuit board inspection method has a problem that the inspection time is prolonged.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a circuit board inspection method and a circuit board inspection apparatus capable of reducing the inspection time.

In order to achieve the above object, a circuit board inspection method according to claim 1 includes: each terminal portion of a conductor pattern formed on a circuit board to be inspected; and capacitance measuring means disposed at a predetermined position with respect to the circuit board. When the ratio of the measured capacitance for the other terminal portion to the measured capacity for any one terminal portion in the same conductor pattern is outside the predetermined allowable ratio range , The quality of the circuit board is inspected by conducting a continuity test based on a continuity state between the terminal portions.

Circuit board inspection method according to claim 2, wherein, in the circuit board inspection method according to claim 1 Symbol placement for between conductor patterns each other measured capacitance approximates, to perform the insulation test on the basis of the conductive state between the conductor patterns It is characterized by.

  The capacitance between the capacitance measuring means disposed at a predetermined position with respect to the circuit board and the conductor pattern is substantially proportional to the area of the conductor pattern. Therefore, in general, when the measured capacities of two conductor patterns insulated from each other approximate each other, it can be considered that the two conductor patterns may be short-circuited by a solder bridge or the like. In this circuit board inspection method, first, the capacitance between each conductor pattern and the capacitance measuring means is measured, and when there are conductor patterns whose measured capacitances are close to each other, an insulation inspection between the conductor patterns is performed. In this case, since the number of times of measuring the capacitance for each conductor pattern is equal to the number of conductor patterns, the measurement is completed in a short measurement time. Further, the operation for searching for conductor patterns whose measurement capacities are similar to each other can be performed instantaneously by using, for example, a personal computer. Therefore, it is possible to perform the insulation test in an extremely short time compared to the case of performing the insulation test between all the conductor patterns.

Circuit board inspection method according to claim 3, wherein, in the circuit board inspection method according to claim 2, wherein said determining a conductor pattern to be insulation test on the basis of the measured capacitance for the termination.

In the circuit board inspection method according to claims 1 to 3 , first, the capacitance between each terminal portion of the conductor pattern and the capacitance measuring means is measured. In this case, the measured capacities for the end portions in the same conductor pattern are substantially the same when no pattern disconnection occurs. Therefore, when the measured capacity of each terminal end in the same conductor pattern is outside the predetermined allowable range, it is determined that the conductor pattern is disconnected between any terminal ends, and the conductor pattern is electrically connected. Perform an inspection. In this case, the object of the insulation test can be determined using one of the plurality of measurement capacitors for each of the plurality of terminal portions in the same conductor pattern. In such a case, since the capacitance of each conductor pattern serving as a reference when determining the targets for the continuity test and the insulation test is measured in common, it is possible to reduce the time for measuring the capacitance.

5. The circuit board inspection apparatus according to claim 4 , wherein the circuit board inspection apparatus inspects the quality of the circuit board by performing a continuity test based on a continuity state between conductor patterns formed on the circuit board to be inspected. A capacitance measuring means for measuring the capacitance between each conductor pattern disposed at a predetermined position and a discriminating means, and the discriminating means for any one terminal portion in the same conductor pattern When the ratio of the measured capacity of the other terminal portion to the measured capacity is out of a predetermined allowable ratio range , the conductor pattern is determined to be a continuity test target.

The circuit board inspection apparatus according to claim 5 is the circuit board inspection apparatus according to claim 4, wherein the discrimination means performs an insulation inspection based on a conduction state between the conductor patterns with respect to each other between the conductor patterns whose measurement capacities are approximated. It is characterized by performing.

The circuit board inspection apparatus according to claim 6 is characterized in that, in the circuit board inspection apparatus according to claim 5 , the discriminating means determines a conductor pattern to be subjected to insulation inspection based on a measured capacity of the terminal portion. To do.

According to the circuit board inspection method according to claim 1 and the circuit board inspection apparatus according to claim 4 , the ratio of the measurement capacitance for the other termination portion to the measurement capacitance for any one termination portion in the same conductor pattern is When the conductor pattern is out of the predetermined allowable ratio range , the conduction inspection time can be shortened by performing the conduction inspection on the conductor pattern based on the conduction state between the terminal portions.

Further, when the ratio of the measured volume of the other end portion to measure capacitance for any one end portion in the same conductor pattern is out of the predetermined allowable ratio range, performs a continuity check on the conductor pattern As a result, the conductor pattern to be inspected for continuity can be accurately specified.

In addition, according to the circuit board inspection method according to claim 2 and the circuit board inspection apparatus according to claim 5 , the capacitance between each conductor pattern and the capacitance measuring means is measured, and the measured measurement capacitance approximates the conductor. By performing the insulation inspection between the patterns, the insulation inspection can be performed in a very short time compared to the case of performing the insulation inspection between all the conductor patterns.

Further, according to the circuit board inspection apparatus for circuit board inspection method and claim 6 according to claim 3, by determining the conductor pattern to be insulation test on the basis of the measured capacitance of the terminal end, the continuity test As a result, the capacitance of each conductor pattern serving as a reference when determining the object of the insulation inspection can be measured in common, so that the capacitance measurement time can be shortened.

  Preferred embodiments of a circuit board inspection method and a circuit board inspection apparatus according to the present invention will be described below with reference to the accompanying drawings.

  First, the configuration of the circuit board inspection apparatus 1 will be described with reference to the drawings.

  As shown in FIG. 1, the circuit board inspection apparatus 1 includes a control apparatus 2 that executes various controls in the circuit board inspection, and probes 3a and 3b for conducting continuity insulation inspection and capacitance measurement (hereinafter, when not distinguished from each other) XY moving mechanisms 4a and 4b (hereinafter referred to as "X-" when not distinguished from each other) that can move the "probe 3" in the XY direction and the vertical direction (Z direction) with respect to the circuit board PC to be inspected. Y movement mechanism 4 ”) and a capacitance measuring jig 5.

Control device 2, as shown in FIG. 1, a control section 11, ROM 12, P ROM 13, and RAM14 corresponding to determine by means that put the present invention. The control unit 11 performs conduction resistance measurement processing, capacitance measurement processing, movement control of the XY movement mechanism 4, various data processing and calculation processing for the measured capacitance, and pass / fail determination processing for the circuit board PC. Execute. The ROM 12 stores an operation program of the control unit 11 and the like, and the PROM 13 is configured by an EEPROM (Electrically Erasable PROM) and stores proximity information described later. The RAM 14 temporarily stores the calculation result of the control unit 11 and the like.

  The capacity measuring jig 5 includes a flat electrode 6 and a thin insulating plate 7 made of, for example, an insulating film and attached to the upper surface of the electrode 6. The circuit board PC can be fixed at the position.

  Next, an inspection process for the circuit board PC by the circuit board inspection apparatus 1 will be described with reference to FIG.

  In this circuit board inspection apparatus 1, for example, when selecting a non-defective circuit board PC at the start of mass production, any one circuit board PC of unknown quality among the mass-produced circuit board PCs is placed on the capacitance measuring jig 5. Secure to. At this time, the lower surface of the circuit board PC is brought into contact with the upper surface of the insulating plate 7 in the capacitance measuring jig 5 so that the circuit board PC and the electrode 6 are kept separated from each other by a predetermined distance.

  Next, as shown in FIG. 2, the capacitance of each conductor pattern P is measured (step 21). At this time, the controller 11 controls the driving of the XY moving mechanisms 4a and 4b, so that, for example, the probes 3a and 3b are arranged in the order of the terminal portions PA1, PA2 and PA3 of the conductor pattern PA shown in FIG. Touch alternately. In this case, the control unit 11 measures the capacitance between the conductor pattern PA and the electrode 6 when the probe 3 is brought into contact with the terminal end PA1, and stores the measured capacitance in the RAM 14 as measurement data DA1. Thus, the measured capacities when the probe 3 is brought into contact with the terminal portions PA2 and PA3 are stored in the RAM 14 as data DA2 and DA3, respectively. Subsequently, for the other conductor pattern PB, the control unit 11 similarly stores the measurement capacitance when the probe 3 is brought into contact with the terminal portions PB1, PB2, and PB3 in the RAM 14 as measurement data DB1, DB2, and DB3, respectively. Remember me. Thereafter, the control unit 11 similarly measures the capacitance between each terminal portion and the electrode 6 for all the other conductor patterns P, and stores the measurement data in the RAM 14. In this case, since the number of times of measurement of the capacitance is equal to the number of terminal portions, the measurement is completed in a short measurement time.

  Next, the control part 11 performs the disconnection determination process about each conductor pattern P based on the measurement data memorize | stored in RAM14 (step 22). This determination process is performed based on the principle described below. That is, the measured capacities at the end portions in the same conductor pattern P are substantially the same when the conductor pattern P is not disconnected. Therefore, for example, when the measured capacities of the terminal portions PA1 to PA3 in the conductor pattern PA deviate from a predetermined allowable range (for example, 95% to 100%) with respect to the maximum capacity, any of the conductor patterns PA It can be determined that there is a possibility of disconnection between the end portions.

  For this reason, specifically, the control unit 11 groups the measurement capacitances for each net number (conductor pattern number) corresponding to each conductor pattern P as shown in FIG. According to the sort program, the measurement capacities in the group are arranged in descending order. Next, it is determined whether or not the measurement capacitance corresponding to each terminal portion in the same conductor pattern P is within the allowable range described above. After performing these determination processes for all the conductor patterns P, it is determined whether or not there is a possibility of disconnection (step 23).

  When it is determined that there is a possibility of disconnection, the control unit 11 creates a data file for continuity inspection in the RAM 14 (step 24). At this time, the terminal number and net number outside the allowable range are written by the control unit 11 in the data file for continuity test. When the creation of the continuity test data file is completed, or when it is determined that there is no possibility of disconnection, insulation failure determination processing is executed (step 25). This determination process is performed based on the principle described below. That is, since the measured capacitance is substantially proportional to the area of the conductor pattern P, generally, when the measured capacitances of the two conductor patterns P, P insulated from each other approximate each other, both the conductor patterns P, P May be short-circuited by a solder bridge or the like. Therefore, for example, the maximum capacity among the measured capacities of the terminal portions PB1 to PB3 in the conductor pattern PB is predetermined with respect to the maximum capacity of the measured capacities of the terminal portions PA1 to PA3 in the conductor pattern PA. When it is within the range (for example, 70% to 100%), it can be determined that the conductor patterns PA and PB may be short-circuited with each other.

  Therefore, according to the sort program stored in the ROM 12, the control unit 11 arranges the maximum measured capacities for the already arranged conductor patterns P in descending order as shown in FIG. Next, the control unit 11 determines that the (n + 1) th largest measurement capacity is within a predetermined range with respect to the nth (n is an integer from the value 1 to a value one minute smaller than the number of conductor patterns P). Are determined one after another, and thereafter, it is determined whether or not there is a possibility of causing an insulation failure due to a short circuit or the like (step 26). At this time, the control unit 11 determines the conductor patterns P and P that cannot cause a short circuit among the conductor patterns P and P whose measured capacitance is within a predetermined range based on the proximity information stored in the PROM 13. About each other, it determines with the thing which has not produced the insulation defect, and excludes it from an insulation test object. As a result, the conductor pattern P to be subjected to insulation inspection can be narrowed down, so that the insulation inspection time performed thereafter can be shortened.

  When it is determined that there is a possibility that an insulation failure has occurred, the control unit 11 creates an insulation inspection data file in the RAM 14 (step 27). At this time, in the data file for insulation inspection, a pair of net numbers (for example, the net numbers of the pair of conductor patterns PA and PB in the above example) that may cause an insulation failure are stored in the control unit. 11 is written. In this case, when the control unit 11 determines that there is no possibility of pattern disconnection failure or insulation failure, the control unit 11 determines that the circuit board PC is a non-defective product and ends the inspection process. On the other hand, when it is determined that there is no possibility that the insulation inspection data file has been generated or that there is a possibility that an insulation failure has occurred, the continuity test is executed (step 28).

  At the time of the continuity test, the control unit 11 drives the XY movement mechanisms 4a and 4b according to the data content of the data file for continuity test, so that the probe 3a, 3b is contacted, and the conduction resistance between both end portions is measured. Similarly, the control part 11 measures all the conduction | electrical_connection resistance between each other 1 pair of termination | terminus parts shown by the data file for continuity inspection. Subsequently, the control part 11 discriminate | determines the presence or absence of a disconnection (step 29). At this time, the control unit 11 determines that no disconnection has occurred when all measured conduction resistances are less than the specified resistance value, and determines that no disconnection has occurred between the terminal portions where the conduction resistance exceeds the specified resistance value. It determines with it being a non-defective board | substrate (step 33), and complete | finishes this test | inspection process.

  On the other hand, when the continuity test data file has not been created or when it is determined that no disconnection has occurred (step 29) and the insulation test data file has been created, the insulation test is executed. (Step 30). In this insulation inspection, the control unit 11 drives the XY moving mechanisms 4a and 4b according to the data contents of the insulation inspection data file, thereby attaching the probes 3a and 3b to the conductor patterns P and P to be insulated. Contact is made and the conduction resistance between the two conductor patterns P and P is measured. Similarly, the control unit 11 measures all the conduction resistances between the other conductor patterns P and P shown in the data file for insulation inspection. Next, the control unit 11 determines whether there is an insulation failure (step 31). In this case, the control unit 11 determines that the substrate is a defective substrate when there is a conductor pattern P between which the conduction resistance is less than the specified resistance value (step 32), and ends the inspection process. On the other hand, when all the measured conduction resistances are equal to or greater than the specified resistance value, the control unit 11 determines that the circuit board PC is a good product because no insulation failure has occurred. As a result, a non-defective circuit board PC at the time of mass production is selected, and inspection data can be absorbed from the non-defective circuit board PC.

  Thus, according to this circuit board inspection apparatus 1, by measuring the capacitance prior to the continuity test and the insulation test, and specifying the continuity insulation test object based on the measured capacity, the continuity insulation test object As a result of narrowing down the conductor pattern P, the continuity test and the insulation test can be completed in a very short time. Specifically, the above example (1000 independent conductor patterns P are formed on one circuit board PC, and three terminal portions are formed on each of the conductor patterns P on average, respectively. In the case of ()), the number of times of capacitance measurement is approximately equal to the number of times of the conventional continuity test. On the other hand, when neither a continuity test object nor an insulation test object exists, the subsequent continuity test and insulation test become unnecessary. For this reason, in the conventional circuit board inspection method, even for a non-defective circuit board PC, an insulation inspection of an enormous number of times of about 500,000 times is always required. As a result, it is possible to sort out the non-defective circuit board PC very quickly as a result of eliminating the need for the insulation inspection itself. Further, even when there is a conductor pattern P determined to require continuity insulation inspection, the continuity insulation inspection time can be drastically reduced as a result of the drastic decrease in inspection targets of the continuity inspection and insulation inspection.

  The present invention is not limited to the configuration shown in the above-described embodiment of the invention. For example, in the embodiment of the present invention, in the continuity inspection (step 28) and the insulation inspection (step 31), the example in which the inspection process is terminated when disconnection or insulation failure has occurred even at one place has been described. Based on the measured conduction resistance between each pair of terminations, the control unit 11 is identified as to which of the terminations is broken, and the identified pair of termination numbers is specified as a failure. For example, the file can be written on a floppy disk. Similarly, based on the measured conduction resistance between each pair of conductor patterns P, P, the control unit 11 is specified which insulation pattern has occurred between which conductor patterns P, P, and The net number of the specified pair of conductor patterns P, P can be written as a failure specifying file, for example, on a floppy disk. In such a case, it is possible to quickly and easily identify the defective part by referring to the contents of the floppy disk.

  In the embodiment of the present invention, the example in which the flat electrode 6 is used as the capacity measuring means has been described. However, the capacity measuring means is not limited to this and is configured in a probe shape movable in the XYZ directions. You can also. Furthermore, in the embodiment of the present invention, the example in which the circuit board PC is formed on one surface side of the circuit board PC has been described. However, the conductor pattern P is formed on both surfaces of the circuit board PC, or through holes are formed. Of course, when the conductor patterns P, P on both sides are connected in common, the inspection process can be performed in the same manner by inverting the front and back of the circuit board PC.

It is a block diagram which shows the structure of the circuit board inspection apparatus 1 which concerns on embodiment of this invention. It is a flowchart of the test | inspection process in the circuit board test | inspection apparatus 1 which concerns on embodiment of this invention. It is a data block diagram which shows an example of the arranged measurement data for specifying the continuity test object produced in the circuit board test | inspection apparatus 1 which concerns on embodiment of this invention. It is a data block diagram which shows an example of the alignment measurement data for specifying the insulation test object produced in the circuit board inspection apparatus 1 which concerns on embodiment of this invention. It is a pattern diagram which shows the example of formation of the conductor pattern P on the circuit board PC for demonstrating the principle at the time of specifying the conduction insulation test object in the circuit board test | inspection apparatus 1 which concerns on embodiment of this invention. It is a pattern diagram which shows the example of formation of the conductor pattern P on the circuit board PC for demonstrating the conventional circuit board inspection method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board inspection apparatus 2 Control apparatus 5 Capacitance measuring jig 6 Electrode 7 Insulating plate 11 Control part 13 PROM
14 RAM

Claims (6)

The capacitance between each terminal portion of the conductor pattern formed on the circuit board to be inspected and the capacitance measuring means disposed at a predetermined position with respect to the circuit board is measured, and any one of the same conductor pattern is measured. When the ratio of the measured capacitance for the other termination portion to the measured capacitance for one termination portion is outside a predetermined allowable ratio range , the conductive pattern is based on the conduction state between the termination portions. A circuit board inspection method for inspecting the quality of the circuit board by conducting a continuity test. The conductor for the pattern between each other, the circuit board inspection method according to claim 1 Symbol placement and performing insulation test on the basis of the conductive state between the conductor patterns the measured capacitance approximates. The circuit board inspection method according to claim 2, wherein the conductor pattern to be subjected to the insulation inspection is determined based on the measured capacitance of the terminal portion. In a circuit board inspection apparatus that inspects the quality of the circuit board by conducting a continuity test based on the continuity state between conductor patterns formed on the circuit board to be inspected,
Capacitance measuring means for measuring the capacitance between each conductor pattern disposed at a predetermined position with respect to the circuit board, and a discriminating means,
When the ratio of the measured capacitance for the other end portion to the measured capacitance for any one end portion in the same conductor pattern is outside a predetermined allowable ratio range , the determining means Is determined to be a target of the continuity test. Said determining means, said relative to each other between the conductor patterns measured capacitance approximates claim 4 Symbol mounting of the circuit board inspection apparatus and performing insulation test on the basis of the conductive state between the conductor patterns. The circuit board inspection apparatus according to claim 5 , wherein the determination unit determines the conductor pattern to be subjected to the insulation inspection based on the measured capacitance of the terminal portion.

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