JP2012117991A - Circuit board inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board inspection device in which there is no need to separately set a via to be used as a part of a cancellation current path while cancelling induced electromotive force generated in a voltage detection path by using induced electromotive force derived from a cancellation current.SOLUTION: A circuit board inspection device comprises a pair of contact terminals 2e and 3e respectively provided correspondingly to probe units 2 and 3 and coming into contact with each other when probes 2a to 2d and probes 3a to 3d of the probe unites 2 and 3 are brought into contact with corresponding contact points TP1 to TP4; and a cancellation current supply part 5 connected to the pair of contact terminals 2e and 3e for outputting a cancellation current I2. In the circuit board inspection device, a processing part 8 controls the cancellation current supply part 5 for supplying the cancellation current I2 to a cancellation current path including the pair of contact terminals 2e and 3e, so as to generate cancellation electromotive force for cancelling induced electromotive force, which is generated in a voltage detection path including a target via 31 and the voltage detection probes 2b and 3b due to a measurement current I1 flowing through a measurement current path including the current supply probes 2a and 3a and the target via 31.

Description

  The present invention relates to a circuit board inspection apparatus that performs inspection by bringing a pair of probe units including a plurality of probes into contact with a circuit board from both sides of the circuit board.

  As this type of circuit board inspection apparatus, the present applicant has already proposed a circuit board inspection apparatus disclosed in Patent Document 1 below. The circuit board inspection apparatus includes a first probe unit disposed on one side of the circuit board, a second probe unit disposed on the other side of the circuit board, a measurement current supply unit, , A voltage measurement unit, an arbitrary one of the plurality of probes of the first probe unit, and an arbitrary one of the plurality of probes of the second probe unit are selected to measure current And electrically connecting to the supply unit, and any other one of the plurality of probes of the first probe unit and any other one of the plurality of probes of the second probe unit. A switching unit that selects a probe and is electrically connected to the voltage measurement unit, a cancellation current supply unit, and a processing unit that executes control of the switching unit and the cancellation current supply unit are provided.

  In this circuit board inspection apparatus, when an inspection object that penetrates from one surface of the circuit board to the other surface, such as a via formed in the circuit board, is connected to one end side of the via to be inspected. A circuit connected to one of the two probes that are in contact with the first contact point defined on the wiring pattern on the one surface side of the circuit board to be tested and the other end of the via to be inspected Supplying a measurement current to an object to be inspected by using one of two probes in contact with a second contact point defined on the wiring pattern on the other surface side of the substrate as a current supply probe, And the other of the two probes in contact with the first contact point and the other of the two probes in contact with the second contact point are used as voltage detection probes, respectively. Contact When measuring the point-to-point voltage generated between the point and the second contact point, the two probes that are in contact with the third contact point among the plurality of contact points on one surface side of the circuit board. One of the two probes that are in contact with the fourth contact point of the plurality of contact points on one side of the circuit board and the other surface side of the circuit board is used as a canceling current supply probe, respectively. Inspection due to the measurement current flowing in the measurement current path including the current supply probe and the via to be inspected by supplying the cancellation current to the cancellation current path including the via other than the supply probe and the via to be inspected A counter electromotive force is generated to cancel an induced electromotive force generated in a voltage detection path including a target via and a voltage detection probe.

  Therefore, according to this circuit board inspection apparatus, the canceling current path can be formed through the circuit board in the same manner as the measurement current path configured to penetrate through the circuit board, thereby approaching each path. Therefore, the induced electromotive force generated in the voltage detection path including the inspection target due to the measurement current flowing in the measurement current path including the via to be inspected can be attributed to the cancellation current flowing in the cancellation current path. The induced electromotive force generated by the As a result, according to this circuit board inspection apparatus, the voltage value of the point-to-point voltage generated in the via to be inspected can be measured with high accuracy. As a result, the inspection is performed based on the current value of the measurement current and the voltage value of the point-to-point voltage. Since the resistance value of the target via can be measured with high accuracy, the inspection accuracy of the inspection object performed based on the resistance value can be sufficiently improved.

JP 2009-2893 (page 8-9, FIG. 1)

  However, the circuit board inspection apparatus has the following problems to be solved. That is, in this circuit board inspection apparatus, a cancellation current path is configured using vias formed in the circuit board. For this reason, in this circuit board inspection apparatus, it is possible to make the relative current path close to the measurement current path as described above. However, this circuit board inspection apparatus is provided for each type of circuit board or the same type. In each circuit board, it is necessary to individually set a via to be used as a part of the cancellation current path for each via to be inspected, and there is a problem to be solved that this individual setting work is troublesome. Existing.

  The present invention has been made to solve such a problem, and is used as a part of a canceling current path while canceling the induced electromotive force generated in the voltage detection path with the induced electromotive force generated due to the canceling current. An object of the present invention is to provide a circuit board inspection apparatus that does not require individual setting of vias.

  In order to achieve the above object, a circuit board inspection apparatus according to claim 1 is provided with a plurality of probes and disposed on one surface side of the circuit board on a plurality of wiring patterns formed on the one surface. A first probe unit configured to be able to simultaneously contact two corresponding probes of the plurality of probes with each defined contact point, and a plurality of probes, and on the other surface side of the circuit board A second probe configured to be able to simultaneously contact two corresponding probes of the plurality of probes with each contact point defined on the plurality of wiring patterns formed on the other surface. A unit, a measurement current supply unit that outputs a measurement current, a voltage measurement unit, an arbitrary one of the plurality of probes of the first probe unit, and the second probe An arbitrary one of the plurality of probes of the first probe unit is selected and electrically connected to the measurement current supply unit, and another arbitrary one of the plurality of probes of the first probe unit is selected. A switching unit that selects one probe of the second probe unit and another arbitrary one of the plurality of probes of the second probe unit and electrically connects to the voltage measuring unit; a processing unit; And the processing unit moves the first and second probe units to bring the plurality of probes into contact with the corresponding contact points, and controls the switching unit in that state to control the circuit board. Before contacting the first contact point defined on the wiring pattern on the one surface side connected to one end side of the via to be inspected among the plurality of vias formed in One of the two probes and the two probes that are in contact with a second contact point defined on the wiring pattern on the other surface side connected to the other end side of the via Are connected to the measurement current supply unit as current supply probes, respectively, and contact the other of the two probes that are in contact with the first contact point and the second contact point. The other of the two probes is connected as a voltage detection probe to the voltage measurement unit, and the measurement current supply unit is controlled to the via to be inspected via the current supply probe. The measurement current is supplied, and the voltage measurement unit is controlled to measure the voltage between points generated between the first contact point and the second contact point. A circuit board inspection apparatus for measuring the resistance of the via to be inspected based on the measured current and the voltage between the points by a four-terminal method and inspecting the via based on the resistance, A pair of contact terminals respectively disposed on the first and second probe units and in direct contact with each other when the plurality of probes of the first and second probe units contact the corresponding contact points; A canceling current supply unit that is connected to the pair of contact terminals and outputs a canceling current, and the processing unit controls the canceling current supply unit to pass the canceling current path including the pair of contact terminals to the canceling current path. The counter current is supplied, and the measurement current flows through the measurement current path including the current supply probe and the via to be inspected. Generating an offset electromotive force to cancel the induced electromotive force generated in the voltage detection path comprising a via and said voltage detection probe.

  In the circuit board inspection apparatus according to claim 1, the contact terminal disposed in the first probe unit and the contact terminal disposed in the second probe unit are directly contacted to form a canceling current path. A cancellation current is supplied to the cancellation current path. Therefore, according to the circuit board inspection apparatus, even if the type of the circuit board is changed or the via to be inspected is changed in the same type of circuit board, the pair of contact terminals is always used to cancel the current path. Therefore, for each type of circuit board or for each via to be inspected even in the same type of circuit board, it takes time and effort to individually set a via to be used as a part of the cancellation current path Work (individual setting work) can be made unnecessary. In addition, according to this circuit board inspection device, by supplying a cancellation current to the cancellation current path, a measurement current flows in the measurement current path including the via to be inspected, and thus the voltage detection path including the via is generated. The induced electromotive force to be canceled can be reliably canceled by the induced electromotive force generated due to the canceling current flowing through the canceling current path. As a result, according to this circuit board inspection apparatus, the voltage measurement unit can measure the inter-point voltage generated between the contact points (voltage generated in the via to be inspected) with high accuracy. Since the resistance value of the via to be inspected can be measured with high accuracy based on the current value of the current and the voltage value between the points, the accuracy of via inspection performed based on the resistance value can be sufficiently improved. .

FIG. 2 is a configuration diagram of the circuit board inspection apparatus 1 in a retracted state (a state where the probe units 2 and 3 are located at a retracted position). It is a block diagram in the contact state (state in which the probe units 2 and 3 are located in a contact position) of the circuit board inspection apparatus 1.

  Hereinafter, embodiments of a circuit board inspection apparatus will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the circuit board inspection apparatus 1 includes a pair of probe units 2 and 3, a measurement current supply unit 4, a cancellation current supply unit 5, a voltage measurement unit 6, a switching unit 7, a processing unit 8, and a storage unit 9. And vias 31 and 32 to be inspected among a plurality of conductor parts (for example, wiring patterns 21, 22, 23, and 24 and vias 31 and 32) formed on the circuit board 11. It is configured to be able to perform an inspection on. 1, each of the vias 31 and 32 shows a state in which the circuit board 11 is a single-layer circuit board and is configured by a single via formed on the circuit board. Although not shown in the drawings, the via includes a configuration in which a single via formed in each layer is connected to each other when the circuit board 11 is a multilayer circuit board.

  In addition, contact points TP1 to TP4 for bringing a probe, which will be described later, into contact with each wiring pattern 21 to 24 of the circuit board 11, are defined in advance. Specifically, wiring patterns 21 and 22 are formed on one surface of the circuit board 11 (upper surface in the figure), and the wiring pattern 21 connected to one end side of the via 31 includes a via pattern. A contact point TP1 used when inspecting 31 is defined. The wiring pattern 22 connected to one end side of the via 32 defines a contact point TP2 used when the via 32 is inspected.

  On the other hand, wiring patterns 23 and 24 are formed on the other surface (the lower surface in the figure) of the circuit board 11, and the wiring pattern 23 connected to the other end side of the via 31 has a via 31. A contact point TP3 that is used when inspecting is defined. The wiring pattern 24 connected to the other end side of the via 32 defines a contact point TP4 used when the via 32 is inspected. In the following, when the contact points TP1 to TP4 are not particularly distinguished, they are also referred to as “contact points TP”.

  The probe unit 2 is a first probe unit, and a plurality (four in this example as an example) of probes 2a, 2b, 2c, 2d, and one formed of a conductive material (for example, a metal material) A contact terminal 2e formed of a conductive material (for example, a metal material) is provided, and on one surface side (upper side in FIG. 1) of the circuit board 11 placed at the inspection position, the inspection position (in FIGS. As shown, a retracted position (position shown in FIG. 1) that allows the circuit board 11 to be placed on the probe unit 2 and the intermediate position 3) and removed from the inspection position, and a contact position. (Position shown in FIG. 2) is configured to be movable by a moving mechanism (not shown). In addition, the probe unit 2 is configured such that when the probe unit 2 is moved to the contact position, two corresponding probes of the probes 2a to 2d are simultaneously in contact with the points TP1 and TP2 defined on the circuit board 11, respectively. ing. In this example, the probe unit 2 is configured such that the pair of probes 2a and 2b are simultaneously in contact with the contact point TP1, and the pair of probes 2c and 2d are simultaneously in contact with the contact point TP2.

  The probe unit 3 is a second probe unit, and a plurality of (four in this example as an example) probes 3a, 3b, 3c, 3d, and one formed of a conductive material (for example, a metal material) The circuit board 11 to the inspection position is provided on the other surface side (lower side in FIG. 1) of the circuit board 11 provided with a contact terminal 3e formed of a conductive material (for example, metal material) and placed at the inspection position. Can be moved by a moving mechanism (not shown) between a retracted position (position shown in FIG. 1) that enables the circuit board 11 to be taken out from the mounting and inspection position and a contact position (position shown in FIG. 2). It is configured. In addition, the probe unit 3 is configured such that when the probe unit 3 is moved to the contact position, two corresponding probes of the probes 3a to 3d are simultaneously in contact with the contact points TP3 and TP4 defined on the circuit board 11, respectively. Has been. In this example, the probe unit 3 is configured such that the pair of probes 3a and 3b are simultaneously in contact with the contact point TP3 and the pair of probes 3c and 3d are simultaneously in contact with the contact point TP4.

  Further, the pair of contact terminals 2e and 3e provided on the probe units 2 and 3 are provided at positions facing each other, and as shown in FIG. 2, both the probe units 2 and 3 are located at the contact positions. Only when the circuit board 11 is in contact with each other, the tip portions of the circuit board 11 are in direct contact with each other.

  The measurement current supply unit 4 is controlled by the processing unit 8 to output the measurement current I1 (DC constant current (current value Ix1) as an example) from a pair of output terminals (not shown) and supply the measurement current I1 to the switching unit 7. .

  The canceling current supply unit 5 is controlled by the processing unit 8 and outputs a canceling current I2 (DC constant current (current value Ix2) as an example) from a pair of output terminals (not shown). Further, the pair of output terminals of the canceling current supply unit 5 is connected to the pair of cables 12 (the cable introduced from the outside of the probe unit 2 to the contact terminal 2e and the probe unit 3 from the outside to the inside. The cable is connected to the contact terminals 2e and 3e via a cable leading to the terminal 3e. With this configuration, the canceling current supply unit 5 is controlled by the processing unit 8 when both the probe units 2 and 3 are located at the contact positions (when the contact terminals 2e and 3e are in contact), The cable 12, the contact terminal 3e, the contact terminal 2e, and the outside of the probe unit 2 that are introduced from the outside of the probe unit 3 to the inside of the probe unit 3 to reach the contact terminal 3e. Is output to the canceling current path that reaches the other output terminal via the cable 12 that is introduced from the inside to the contact terminal 2e, and thereby outputs the canceling current I2 (DC constant current (current value Ix2) as an example). The canceling current I2 is supplied between the contact terminal 2e disposed at 2 and the contact terminal 3e disposed at the probe unit 3. The current value Ix2 is set in advance to the same value as the current value Ix1.

  The voltage measuring unit 6 is controlled by the processing unit 8 to input the voltage V1 output from the switching unit 7 through a pair of input terminals, and measure and output the voltage value Vx1.

  The switching unit 7 is configured as a scanner by combining a plurality of changeover switches. Further, the switching unit 7 includes all the probes 2a to 2d and 3a to 3d of each probe unit 2 and 3, and individual cables 13 (cables that are introduced from the outside of the probe unit 2 to the inside to reach the probes 2a to 2d). , And a cable that is introduced from the outside to the inside of the probe unit 3 and reaches each of the probes 3a to 3d), and the measurement current supply unit 4 and the voltage measurement unit 6 are connected with individual cables (not shown). Connected through.

  Further, the switching unit 7 is controlled by the processing unit 8, and any one of the probes 2 a to 2 d of the probe unit 2 and any one of the probes 3 a to 3 d of the probe unit 3. The two probes are selected, and these two probes are connected as measurement current supply probes to a pair of output terminals of the measurement current supply unit 4 via the cable 13. Further, the switching unit 7 is controlled by the processing unit 8, and another arbitrary one of the probes 2 a to 2 d of the probe unit 2 (other probes excluding the probe connected to the measurement current supply unit 4). One of the probes) and any other one of the probes 3a to 3d of the probe unit 3 (one of the other probes excluding the probe connected to the measurement current supply unit 4) And the two probes are connected as voltage detection probes to the pair of input terminals of the voltage measuring unit 6 via the cable 13.

  The processing unit 8 includes a CPU and operates according to an operation program stored in advance in the storage unit 9 to execute a circuit board inspection process for the circuit board 11 placed at the inspection position. Control is performed for the moving mechanism that moves the probe units 2 and 3, the measurement current supply unit 4, the cancellation current supply unit 5, the voltage measurement unit 6, and the switching unit 7. The storage unit 9 is composed of a ROM and a RAM, and inspects an operation program for the processing unit 8, information on the wiring patterns 21 to 24 and the vias 31 and 32 formed on the circuit board 11, and an inspection target. List of probes for each test object used to measure the resistance value by the four probe method, the use of the probe (whether it is used as a measurement current supply probe or a voltage detection probe), and the test object A reference value (reference resistance value Rref) for determining whether the via is good or bad is stored in advance. The storage unit 9 stores current values Ix1 and Ix2 (= Ix1) of the measurement current I1 and the cancellation current I2. The output unit 10 is configured by a display device as an example, and displays the result of the inspection process output from the processing unit 8.

  Next, the operation of the circuit board inspection apparatus 1 will be described with reference to FIGS. It is assumed that the circuit board 11 is previously placed at the inspection position.

  In this state, in this circuit board inspection apparatus 1, the processing unit 8 operates according to the operation program and starts the circuit board inspection process. In this circuit board inspection process, the processing unit 8 first controls the moving mechanism to move the probe units 2 and 3 from the retracted position shown in FIG. Move to contact position. Accordingly, in the probe unit 2, the pair of probes 2a and 2b are in contact with the contact point TP1, and the pair of probes 2c and 2d are in contact with the contact point TP2. In the probe unit 3, the pair of probes 3a and 3b are in contact with the contact point TP3, and the pair of probes 3c and 3d are in contact with the contact point TP4. The contact terminals 2e and 3e of the probe units 2 and 3 are in contact with each other.

  Next, the processing unit 8 controls the switching unit 7 in this state to connect the measurement current supply unit 4 and the voltage measurement unit 6 to one of the vias to be inspected first. In this case, the processing unit 8 reads out one of the vias to be inspected from the storage unit 9 and stores information on the probe used when inspecting the one inspection target and the use of the probe. Read from unit 9. Further, the processing unit 8 controls the switching state of the switching unit 7 based on the read information, so that a pair of probes serving as measurement current supply probes can be connected to the output terminals of the measurement current supply unit 4 via the cable 13. And a pair of probes serving as voltage detection probes are connected to the voltage measuring unit 6 via the cable 13.

  As an example, when the processing unit 8 reads out the via 31 as the first inspection target from the storage unit 9, the probe used when inspecting the inspection target and information on the use of the probe are further stored from the storage unit 9. read out. In this case, the processing unit 8 uses the two contact points TP1 (first contact points) defined on the wiring pattern 21 connected to one end side of the via 31 as information on the probe to be used. Information about the probes 2a and 2b and the two probes 3a and 3b in contact with the contact point TP3 (second contact point) defined in the wiring pattern 23 connected to the other end of the via 31 read out.

  Further, the processing unit 8 uses one of the two probes 2a and 2b (probe 2a in this example) and one of the two probes 3a and 3b (in this example, the probe 3a) as information on the usage of the probe. ) As a measurement current supply probe, and the other of the two probes 2a and 2b (probe 2b in this example) and the other of the two probes 3a and 3b (probe 3b in this example) is a voltage. Read information about the detection probe. The processing unit 8 controls the switching unit 7 based on the read information about the probe to be used and its application, and connects the probes 2a and 3a as measurement current supply probes to the measurement current supply unit 4, Probes 2 b and 3 b serving as voltage detection probes are connected to the voltage measuring unit 6.

  Subsequently, the processing unit 8 performs a measurement process of the resistance value R for the via 31 to be inspected. In this measurement process, the processing unit 8 first controls the measurement current supply unit 4 and the cancellation current supply unit 5 to simultaneously start the output of the measurement current I1 and the cancellation current I2, and also controls the voltage measurement unit 6 to The measurement of the voltage V1 is started.

  As an example, the processing unit 8 is connected to the measurement current supply unit 4 via the switching unit 7 to the measurement current path (one cable 13 (the cable 13 on the probe unit 2 side), this one cable 13. The probe unit 2 is connected to the probe 2a, the wiring pattern 21, the via 31, the wiring pattern 23, the probe 3a, and another cable 13 connected to the probe 3a (the current path via the cable 13 on the probe unit 3 side). Is supplied with the measurement current I1 in the direction of the probe unit 3. As a result, due to the measurement current I1 flowing through the via 31, a voltage (voltage between points) V1 is generated between the contact points TP1 and TP3 defined in the wiring patterns 21 and 23. Therefore, the processing unit 8 is connected to the voltage measuring unit 6 with one cable 13 and switching unit 7 on the probe unit 2 side connected to the probe 2b, and 1 on the probe unit 3 side connected to the probe 3b. The voltage value Vx1 of the voltage V1 is measured through the cable 13 and the switching unit 7. Further, in this example, the processing unit 8 causes the cancellation current I2 to flow from the probe unit 3 toward the probe unit 2 so as to be opposite to the measurement current I1 with respect to the cancellation current supply unit 5. Is output to the above-described canceling current path.

  In this state, due to the measurement current I1 flowing through the measurement current path, the switching unit 7, one cable 13 connected to the probe 2b, the probe 2b, the wiring pattern 21, the via 31, the wiring pattern 23, The induced electromotive force is large in a predetermined period from the start of supply (application) of the measurement current I1 to the voltage detection path reaching the switching unit 7 via the probe 3b and one other cable 13 connected to the probe 3b. Occurs at the level. However, in this circuit board inspection apparatus 1, the cable 13 introduced from the outside of the probe unit 2 to the probe (2a or 2c) and the probe 13 (3a or 3c) introduced from the outside of the probe unit 3 to the inside. In the same way as the measurement current path configured to include the cable 13 leading to the circuit board 11, that is, the measurement current path configured to penetrate the circuit board 11, the cable that is introduced from the outside to the inside of the probe unit 2 and reaches the contact terminal 2e. 12 and a canceling current path including the cable 12 introduced from the outside to the inside of the probe unit 3 and reaching the contact terminal 3e, that is, a canceling current path penetrating a plane including the circuit board 11 in the vicinity of the circuit board 11, Counter current with the same current value as the measurement current I1 in the opposite direction to the measurement current I1 flowing in the measurement current path It is supplying the I2.

  Therefore, the induced electromotive force (first induced electromotive force) generated in the voltage detection path due to the supply of the measurement current I1 and the induced electromotive force (second electromotive force) generated in the voltage detection path due to the supply of the canceling current I2 The induced electromotive force) is substantially the same in magnitude and opposite in direction, so that the induced electromotive force (second induced electromotive force) generated in the voltage detection path cancels the induced electromotive force (first induced electromotive force). By acting, the induced electromotive force generated in the voltage detection path due to the measurement current I1 flowing in the measurement current path is greatly reduced. As a result, the waveform of the voltage V1 input to the voltage measurement unit 6 is a waveform that is extremely less affected by the induced electromotive force due to the flow of the measurement current I1.

  Next, the processing unit 8 inputs the voltage value Vx1 measured by the voltage measuring unit 6, and calculates the resistance value R of the via 31 by dividing by the current value Ix1 (= Ix2) read from the storage unit 9. And stored in the storage unit 9. This completes the measurement process of the resistance value R by the four-terminal method for the via 31 to be inspected.

  Subsequently, the processing unit 8 reads the resistance value R of the via 31 calculated in the above-described measurement process and the reference resistance value Rref of the via 31 and compares them, and the resistance value R is equal to or less than the reference resistance value Rref. When the resistance value R exceeds the reference resistance value Rref, it is determined that the via 31 is normal. Further, the processing unit 8 stores the inspection result in the storage unit 9 in association with the information (identification information) of the inspection target (via 31). Thereby, the inspection process for one inspection object is completed.

  Thereafter, the processing unit 8 determines whether or not there is an uninspected inspection target (via) among the inspection targets stored in the storage unit 9, and performs each of the above processes performed on the via 31. Are repeatedly executed to inspect all the vias to be inspected (the remaining vias 32 in this example).

  Next, after the inspection for all the vias (vias 31 and 32 in this example) is completed, the processing unit 8 reads the inspection results for all the vias from the storage unit 9 and displays them on the output unit 10. Finally, the moving mechanism is operated to move the probe units 2 and 3 from the contact position to the retracted position. Thereby, the circuit board inspection process is completed.

  As described above, in this circuit board inspection apparatus 1, the canceling current path using the contact terminal 2e disposed on the probe unit 2 and the contact terminal 3e disposed on the probe unit 3 and in direct contact with the contact terminal 2e. And a canceling current I2 is supplied to the canceling current path. Therefore, according to the circuit board inspection apparatus 1, even if the type of the circuit board is changed or even when the via to be inspected is changed in the same type of circuit board, the contact terminals 2e and 3e are always used to cancel each other. Since a current path can be formed, it is troublesome to individually set a via to be used as a part of a cancellation current path for each type of circuit board or for each via to be inspected even in the same type of circuit board. Such setting work (individual setting work) can be made unnecessary. Further, according to the circuit board inspection apparatus 1, voltage detection including a via is caused by supplying the cancellation current I2 to the cancellation current path and causing the measurement current I1 to flow through the measurement current path including the via to be inspected. The induced electromotive force generated in the path can be surely canceled by the induced electromotive force generated due to the canceling current I2 flowing through the canceling current path. As a result, according to the circuit board inspection apparatus 1, the voltage measuring unit 6 can measure the voltage value Vx1 of the voltage V1 generated in the via to be inspected with high accuracy. As a result, the processing unit 8 can measure the current value of the measured current I1. Since the resistance value R of the vias 31 and 32 to be inspected can be measured with high accuracy based on Ix1 and the voltage value Vx1, the inspection accuracy of the vias 31 and 32 performed based on the resistance value R is sufficiently improved. be able to.

  The circuit board inspection apparatus 1 employs a configuration in which the measurement current I1 is passed from the probe unit 2 side to the probe unit 3 side, and the canceling current I2 is passed from the probe unit 3 side to the probe unit 2 side. However, a configuration in which the measurement current I1 is allowed to flow from the probe unit 3 side to the probe unit 2 side and the offset current I2 is allowed to flow from the probe unit 2 side to the probe unit 3 side may be employed.

  Further, the wiring patterns 21 and 23 connected to the end portions of the via 31 together with the via 31 and the wiring patterns 22 and 24 connected to the end portions of the via 32 together with the via 32 are set as inspection targets including the vias. Of course, it is good.

DESCRIPTION OF SYMBOLS 1 Circuit board inspection apparatus 2,3 Probe unit 2a-2d, 3a-3d Probe 4 Measurement current supply part 5 Cancellation current supply part 6 Voltage measurement part 7 Switching part 8 Processing part 11 Circuit board 21-24 Wiring pattern 31, 32 Via I1 Measurement current I2 Cancellation current TP1 to TP4 Contact point V1 Voltage

Claims (1)

A plurality of probes are provided, and each of the contact points defined on the plurality of wiring patterns formed on the one surface side of the circuit board and corresponding to the two contact points of the plurality of probes is provided. A first probe unit configured to be able to contact two probes simultaneously;
A plurality of probes are provided, and two contact points corresponding to the contact points defined on the plurality of wiring patterns formed on the other surface side of the circuit board and corresponding to the other two of the plurality of probes are provided. A second probe unit configured to be able to contact two probes simultaneously;
A measurement current supply unit for outputting a measurement current;
A voltage measurement unit;
Supplying measurement current by selecting any one of the plurality of probes of the first probe unit and any one of the plurality of probes of the second probe unit. And any other one of the plurality of probes of the first probe unit and the other of the plurality of probes of the second probe unit. A switching unit that selects one probe and electrically connects to the voltage measuring unit;
A processing unit,
The processing unit is formed on the circuit board by moving the first and second probe units to bring the plurality of probes into contact with the corresponding contact points and controlling the switching unit in that state. Of the two probes in contact with the first contact point defined on the wiring pattern on the one surface side connected to one end side of the via to be inspected among the plurality of vias One of the two probes contacting the second contact point defined on the wiring pattern on the other surface side connected to the other end side of the via and the other side of the via Each of the probes is connected to the measurement current supply unit as a current supply probe, and is connected to the other of the two probes in contact with the first contact point and the second contact point. The other of the two probes is connected as a voltage detection probe to the voltage measurement unit, and the measurement current supply unit is controlled to connect to the via to be inspected via the current supply probe. And supplying the measurement current and controlling the voltage measurement unit to measure a voltage between points generated between the first contact point and the second contact point, and based on the measurement current and the voltage between the points. A circuit board inspection apparatus that measures the resistance of the via to be inspected by a four-terminal method and inspects the via based on the resistance,
A pair of contacts disposed on the first and second probe units, respectively, that directly contact each other when the plurality of probes of the first and second probe units contact the corresponding contact points. A terminal,
A canceling current supply unit connected to the pair of contact terminals and outputting a canceling current;
The processing unit controls the canceling current supply unit to supply the canceling current to the canceling current path including the pair of contact terminals, and the measurement current including the current supply probe and the via to be inspected A circuit board inspection apparatus that generates a counter electromotive force that cancels an induced electromotive force generated in a voltage detection path including the via and the voltage detection probe that are to be inspected due to the measurement current flowing in the path.

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