JP2007333598A - Substrate inspecting means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate inspecting means capable of shortening an inspection time, and having high efficiency of a circuit for inspection. <P>SOLUTION: This substrate inspecting device 21 includes a first and second current supply terminals 22, 23, a first and second voltage measuring terminals 24, 25, a current supply section 26, a voltage measurement section 27, and a voltage stabilizing means 28, and inspects a substrate provided with a plurality of wiring patterns 29. The stabilizing means 28 is electrically connected to the second voltage measuring terminal 25, and stabilizes the voltages of the second voltage measuring terminal 25 and the contact part of the wiring pattern 29 with the measuring pattern 25. More concretely, the stabilizing means 28 is provided with an operational amplifier 41. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate inspection apparatus that inspects electrical characteristics of a substrate having a plurality of wiring patterns.

  The present invention is not limited to a printed wiring board, but includes, for example, electrical wiring on various substrates such as flexible substrates, multilayer wiring substrates, electrode plates for liquid crystal displays and plasma displays, and package substrates and film carriers for semiconductor packages. In this specification, these various wiring boards are collectively referred to as “substrates”.

  As a conventional board inspection apparatus, there is an apparatus for inspecting a wiring pattern using a so-called four-terminal method in which two terminals, a current supply terminal and a voltage measurement terminal, are provided (for example, Patent Document 1). In this type of substrate inspection apparatus, as shown in FIG. 3, the positive and negative output portions 1 a and 1 b of the current supply portion 1 are connected to the first and second via the current supply conductive paths 2 and 3 on the positive and negative sides. Current supply terminals 4 and 5 are electrically connected. The current supply unit 1 supplies current to the wiring pattern 7 so as to flow from the first current supply terminal 4 side to the second current supply terminal 5 side. Further, the positive and negative voltage introducing sections 7a and 7b of the voltage measuring section 7 are electrically connected to the first and second voltage measuring terminals 11 and 12 via the positive and negative voltage measuring conductive paths 8 and 9, respectively. Has been. The voltage measuring unit 5 calculates the voltage between two points on the wiring pattern 4 via the first and second voltage measuring terminals 11 and 12 in a state where current is supplied to the wiring pattern 6 by the current supply unit 1. measure. Based on the current value of the current supplied by the current supply unit 1 and the voltage value measured by the voltage measurement unit 7, the conductive characteristics of the wiring pattern 6 are good (whether there is a short circuit or a disconnection, whether the resistance value is appropriate, etc.) ) Is determined.

  In such a four-terminal method, since the impedance of the voltage measuring unit 7 is substantially infinite, the voltage measuring terminals 11 and 12 are separated from the current supply terminals 4 and 5. The current flowing through the contact portion with the wiring pattern 6 is suppressed to a level that can be substantially ignored. As a result, the influence of the contact resistance between the voltage measuring terminals 11 and 12 and the wiring pattern 6 is substantially excluded, and the voltage between two points on the wiring pattern 6 where the voltage measuring terminals 11 and 12 are in contact is accurately measured. It can be done.

  In FIG. 3, the ammeter 13 inserted in the conductive path 3 does not directly contribute to the measurement of the resistance value or the like of the wiring pattern 6, but the current value of the current returning from the wiring pattern 6 to the current supply unit 1. This is used to confirm the above.

Further, the switching elements 14 to 17 inserted in the respective conductive paths 2, 3, 8, and 9 include circuit elements on the current supply unit 1 and voltage measurement unit 7 side and terminals 4, 5, 11, and 12 side. The circuit elements are connected in accordance with a preset order, and are configured by a multiplexer or the like. The number of circuit elements on the terminals 4, 5, 11, and 12 side is larger than the number of circuit elements on the current supply unit 1 and voltage measurement unit 7 side, and the current supply unit 1 and the switching elements 14 to 17 The circuit element on the voltage measuring unit 7 side is selectively connected to the circuit element on any of the terminals 4, 5, 11, 12 side.
JP 2004-184374 A

  However, in the above-described conventional substrate inspection apparatus, since the second current supply terminal 5 and the negative output portion 1b of the current supply unit 1 are simply connected by the conductive path 3, the conductive path 3 and the current path The current flowing to the wiring pattern 6 and the two points on the wiring pattern 6 after the current supply to the wiring pattern 6 is started due to the influence of the resistance component, the capacitance component, etc. of the conductive path in the connected current supply unit 1 It takes time until the voltage becomes stable and accurate voltage measurement can be performed, and there is a problem that inspection takes time.

  Further, since the fluctuation range of the contact resistance at the contact portion between the second current supply terminal 5 and the wiring pattern 6 is large, the time until the current value of the current flowing through the wiring pattern 6 is stabilized also varies greatly. Yes. For this reason, there is also a problem that it is necessary to set a long time from the start of current supply to voltage measurement with a margin.

  In addition, the resistance component of the conductive path 3 and the conductive path in the current supply unit 1 connected thereto may be significantly larger than the resistance value of the wiring pattern 6. In such a case, the ratio between the measured voltage value actually measured by the voltage measuring unit 7 and the output voltage value output from the current supply unit 1 for current supply is increased, and the efficiency of the circuit for inspection is increased. There is also the problem of being bad.

  Accordingly, a first problem to be solved by the present invention is to provide a substrate inspection apparatus capable of shortening the inspection time.

  A second problem to be solved by the present invention is to provide a substrate inspection apparatus having a high efficiency circuit for inspection.

  In order to solve the above-mentioned problem, in the invention of claim 1, there is provided a board inspection apparatus for inspecting electrical characteristics of a board having a plurality of wiring patterns, wherein the wiring pattern is one of the plurality of wiring patterns. First and second current supply terminals that are in contact with the wiring pattern at positions separated from each other, and a section sandwiched between the first current supply terminal and the second current supply terminal in any one of the wiring patterns The first and second voltage measurement terminals that are in contact with the wiring pattern at positions spaced apart from each other, and any one of the wiring patterns via the first current supply and the second current supply terminal. A current supply unit for passing current from the first current supply terminal side to the second current supply terminal side, the first voltage measurement terminal and the second voltage measurement terminal, A voltage measuring unit that measures a voltage between two points of any one of the wiring patterns with which the first voltage measuring terminal and the second voltage measuring terminal are in contact; and a voltage stabilizing unit; Of the measurement terminal and the second voltage measurement terminal, the second voltage measurement terminal is in contact with any one of the wiring patterns on the downstream side of the current, and the voltage stabilizing means is configured to It is electrically connected to the voltage measurement terminal, and stabilizes the voltage of the contact portion between the second voltage measurement terminal and any one of the wiring patterns with the second voltage measurement element.

  According to a second aspect of the present invention, in the substrate inspection apparatus according to the first aspect of the present invention, the voltage stabilizing means includes an operational amplifier.

  According to a third aspect of the present invention, in the substrate inspection apparatus according to the second aspect of the present invention, the positive and negative output sections for supplying current from the current supply section are for supplying positive and negative currents. The first current supply terminal and the second current supply terminal are electrically connected to each other through a conductive path, and the positive and negative voltage introduction sections for voltage measurement of the voltage measurement section are positive A first voltage measurement terminal and a second voltage measurement terminal are electrically connected to the first voltage measurement terminal and the second voltage measurement terminal through a voltage measurement conductive path on the side and the negative side, respectively, and the output terminal of the operational amplifier is the second current supply. It is connected to the terminal side, and the non-inverting input terminal is inserted into the negative-side current supply conductive path so as to be connected to the negative-side output unit side of the current supply unit, and the inverting input terminal is The second voltage measurement terminal is electrically connected.

  According to the first aspect of the present invention, the voltage stabilizing means stabilizes the voltage at the contact portion between the second voltage measuring terminal and the second voltage measuring element of the wiring pattern. Therefore, the first and second current supply terminals and the first and second current measurement terminals are brought into contact with the wiring pattern, and the first and second voltage measurements are performed immediately after the current supply by the current supply unit is started. The voltage between two points on the wiring pattern with which the terminal contacts is stabilized, and there is no variation in the time required for the voltage to stabilize. Therefore, the voltage between two points on the wiring pattern can be accurately measured immediately after the start of current supply, and the time from the start of current supply to voltage measurement and the time required for inspection can be greatly reduced.

  Further, since voltage fluctuations at the contact portion between the second voltage measurement terminal and the second voltage measurement element of the wiring pattern are suppressed, two points on the wiring pattern where the first and second voltage measurement terminals are in contact with each other. The difference between the voltage level between and the output voltage of the current supply unit can be reduced. As a result, the efficiency of the circuit for inspection can be improved.

  According to the second aspect of the present invention, since the operational amplifier is provided in the voltage stabilization means, the voltage at the contact portion between the second voltage measurement terminal and the second voltage measurement element of the wiring pattern is reliably stabilized. The inspection time can be shortened.

  According to the third aspect of the present invention, the voltage at the contact portion between the second voltage measurement terminal and the second voltage measurement element of the wiring pattern is a predetermined constant that is the voltage level of the negative-side current supply conductive path. It is substantially held at a potential (for example, a ground potential). For example, even when the voltage of the contact portion between the second voltage measurement terminal and the second voltage measurement element of the wiring pattern fluctuates at the start of voltage supply by the current supply unit, the voltage varies depending on the output voltage of the output terminal of the operational amplifier. Is instantaneously canceled, and the voltage at the second voltage measuring terminal or the like is held at a constant potential. Therefore, the first and second current supply terminals and the first and second voltage measurement terminals are brought into contact with the wiring pattern, and immediately after the current supply by the current supply unit is started, the first and second voltages are supplied. The voltage between two points on the wiring pattern with which the measurement terminal is brought into contact is stabilized, and there is no variation in the time required for the voltage to stabilize. Therefore, the voltage between two points on the wiring pattern can be accurately measured immediately after the current supply is started, and the time from the start of the current supply to the voltage measurement and the time required for the inspection can be greatly reduced.

  Further, since the voltage at the contact portion between the second voltage measurement terminal and the second voltage measurement element of the wiring pattern is substantially maintained at a predetermined constant potential, the first and second voltage measurement terminals are in contact with each other. A voltage difference substantially equal to the output voltage of the current supply unit is generated between the two points on the wiring pattern. As a result, the efficiency of the circuit for inspection can be improved.

  FIG. 1 is a diagram showing a configuration of a substrate inspection apparatus according to an embodiment of the present invention. As shown in FIG. 1, the substrate inspection apparatus 21 includes first and second current supply terminals 22 and 23, first and second voltage measurement terminals 24 and 25, a current supply unit 26, and voltage measurement. The unit 27 and the voltage stabilizing means 28 are provided, and a substrate (not shown) provided with a plurality of wiring patterns 29 is inspected.

  The current supply terminals 22 and 23 and the voltage measurement terminals 24 and 25 are a pair (terminal pair) of the current supply terminal and the voltage measurement terminal. By using two sets, the electrical characteristics of the desired wiring pattern 29 are measured. More specifically, two terminal pairs are brought into contact with two inspection points on the wiring pattern 29 to be inspected out of the plurality of wiring patterns 29 provided on the substrate, respectively, and the electrical connection between the inspection points is performed. By detecting the characteristics, it is determined whether or not the conductive characteristics of the wiring pattern 29 to be inspected are good (whether there is a short circuit or a disconnection, whether the resistance value is appropriate). For determining whether the electrical conductivity is good or bad, for example, the current value of the current supplied to the wiring pattern 29 by the current supply unit 26 and two points on the wiring pattern 29 measured by the voltage measuring unit 27 while the current is supplied. The resistance value between two points on the wiring pattern 29 (between inspection points) is obtained based on the voltage between them, and the quality of the conductive characteristics of the wiring pattern 29 is determined based on the resistance value. .

  At this time, the first and second current supply terminals 22 and 23 are in contact with the wiring pattern 29 at positions separated from each other on the arrangement path of the wiring pattern 29 to be inspected. The first and second voltage measurement terminals 24 and 25 are wired at positions separated from each other in a section sandwiched between the first and second current supply terminals 22 and 23 on the wiring pattern 29 to be inspected. The pattern 29 is touched. More specifically, the second voltage measurement terminal 24 is in contact with the wiring pattern 29 on the downstream side of the current from the first voltage measurement terminal 25.

  The positive and negative current output units 26a and 26b for supplying current from the current supply unit 26 have first and second current supply terminals via positive and negative current supply conductive paths 31 and 32, respectively. 22 and 23, respectively. Note that the negative-side current supply conductive path 32 includes a reference potential line held at a predetermined constant potential (for example, a ground line held at zero potential).

  Positive and negative voltage introduction units 27a and 27b for voltage measurement of the voltage measurement unit 27 are first and second voltage measurement terminals via positive and negative voltage measurement conductive paths 33 and 34, respectively. 24 and 25, respectively.

  Switching elements (for example, semiconductor switching elements) 35 to 38 are inserted in the conductive paths 31 to 34, respectively. The switching elements 35 to 38 are for switching the circuit elements on the current supply unit 26 and voltage measurement unit 27 side and the circuit elements on the terminals 22 to 25 side in accordance with a preset order. Etc. The number of circuit elements on the terminals 22 to 25 side is larger than the number of circuit elements on the current supply unit 26 and voltage measurement unit 27 side, and the current supply unit 26 and voltage measurement unit 27 are switched by the switching elements 35 to 38. The circuit element on the side is selectively connected to the circuit element on the side of any one of the terminals 22-25.

  The current supply unit 26 includes, for example, a power supply circuit (for example, a power supply circuit capable of adjusting the output voltage) and a current control circuit that controls the current value of the current output from the output units 26a and 26b. ing. For example, the current supply unit 26 outputs a current having a predetermined value via the output units 26a and 26b by the action of the current control circuit.

  As a result, when the first and second current supply terminals 22 and 23 are brought into contact with the wiring pattern 29, the current supply unit 26 causes a current to pass through the first and second current supply terminals 22 and 23, for example. The wiring pattern 29 is supplied with a preset current value. At this time, the direction of the current flowing through the wiring pattern 29 is the direction of flowing from the first current supply terminal 22 side to the second current supply terminal 23 side.

  The voltage measuring unit 27 measures the voltage between two points on the wiring pattern 29 with which the first and second voltage measuring terminals are in contact via the positive and negative voltage introducing units 27a and 27b.

  The voltage stabilization means 28 is electrically connected to the second voltage measurement terminal 25 and stabilizes the voltage of the second voltage measurement terminal 25. More specifically, the voltage stabilizing unit 28 includes an operational amplifier 41. Any device other than the operational amplifier 41 may be used as long as the voltage at the second voltage measurement terminal 25 can be stabilized.

  The voltage stabilizing means 28 stabilizes the potentials of the second current supply terminal 23 and the second voltage measurement terminal 25 at the same potential. This voltage stabilization means 28 stabilizes the potentials of the second current supply terminal 23 and the second voltage measurement terminal 25 at the same potential, so that the second current supply terminal 23 and the second current supply terminal 23 when performing substrate inspection The potential difference at the voltage measurement terminal 25 can be ignored.

  Further, preferably, the voltage stabilization means 28 stabilizes the potentials of the second current supply terminal 23 and the second voltage measurement terminal 25 to the ground potential. In this way, the voltage stabilization means 28 stabilizes the second current supply terminal 23 and the second voltage measurement terminal 25 to the ground potential, so that the charging time for measurement related to these terminals when performing substrate inspection can be reduced. It can be reduced.

  The operational amplifier 41 has an inverting input terminal 41 a, a non-inverting input terminal 41 b, and an output terminal 41 c, the output terminal 41 c faces the second current supply terminal 23, and the non-inverting input terminal 41 b is the negative side of the current supply unit 26. Is inserted into the negative-side current supply conductive path 32 so as to face the output portion 26b side. The inverting input terminal 41 a of the operational amplifier 41 is electrically connected to the second voltage measurement terminal 25. More specifically, the operational amplifier 41 is inserted in the conductive path 32 so as to be positioned closer to the current supply unit 26 than the switching element 36. The inverting input terminal 41 a of the operational amplifier 41 is electrically connected to the conductive path 34 at a position closer to the voltage measurement unit 27 than the switching element 38, and is electrically connected to the second voltage measurement terminal 25 through the conductive path 34. It is connected to the. That is, the non-inverting input terminal 41b of the operational amplifier 41 is electrically connected to a portion (ground line) on the current supply unit 26 side of the conductive path 32, and the inverting input terminal 41a and the output terminal 41c are connected to the terminal 23. , 25 are electrically connected to each other through the conductive paths 32, 34, the terminals 23, 25 and the wiring pattern 29.

  For this reason, when the terminals 23 and 25 are brought into contact with the wiring pattern 29, the operational amplifier 41 sets the voltage at the contact portion between the second voltage measuring terminal 25 and the second voltage measuring element 25 of the wiring pattern 29 to the ground potential ( (Zero potential). Therefore, even if the voltage at the contact portion between the second voltage measuring terminal 25 and the second voltage measuring element 25 of the wiring pattern 29 fluctuates when the current supply unit 26 starts to supply current to the wiring pattern 29, the operational amplifier The fluctuation of the voltage is instantaneously canceled by the output voltage of the output terminal 41c of 41, and the potential of the second voltage measuring terminal 25 and the like is held at the ground potential.

  As a result, the first and second current supply terminals 22 and 23 and the first and second voltage measurement terminals 24 and 25 are brought into contact with the wiring pattern 29 and immediately after the current supply by the current supply unit 26 is started. The voltage between the two points on the wiring pattern 29 with which the first and second voltage measuring terminals 24 and 25 are in contact with each other is stabilized, and there is no variation in time required for the voltage to stabilize. Therefore, the voltage between the two points on the wiring pattern 29 can be accurately measured immediately after the current supply is started, and the time from the start of the current supply to the voltage measurement and the time required for the inspection are greatly reduced. It can be done.

  In addition, since the voltage at the contact portion between the second voltage measurement terminal 25 and the wiring pattern 29 with the second voltage measurement element 25 is substantially held at the ground potential, the first and second voltage measurement terminals 24 are provided. 25, a voltage difference substantially equal to the output voltage of the current supply unit 26 is generated between the two points on the wiring pattern 29 with which they are in contact. As a result, the efficiency of the circuit for inspection can be improved.

  2 shows the first and second when the voltage between two points on the wiring patterns 6 and 29 is measured using the substrate inspection apparatus 21 of FIG. 1 and the conventional substrate inspection apparatus of FIG. 3 according to the present embodiment. 2 is a graph showing voltage transition of two voltage measurement terminals 11, 12, 24, 25. Lines L1 and L2 in FIG. 2 indicate voltage transitions in contact portions with the first and second voltage measurement terminals 24 and 25 of the wiring pattern 29 when voltage measurement is performed using the substrate inspection apparatus 21 in FIG. Is shown. Lines L3 and L4 indicate voltage transitions at the contact portions of the wiring pattern 6 with the first and second voltage measurement terminals 11 and 12 when voltage measurement is performed using the substrate inspection apparatus of FIG. Yes.

  From the lines L3 and L4 in FIG. 2, in the substrate inspection apparatus in FIG. 3, the first and second voltage measurement terminals 11 and 12 of the wiring pattern 6 are started after the current supply to the wiring pattern 6 is started at time Ta. It can be seen that it takes a considerable amount of time for the voltage at the contact portion to stabilize. Further, the current after the contact portion between the second current supply terminal 5 and the wiring pattern 6 is compared with the voltage difference between the two points of the wiring pattern 6 with which the first and second voltage measurement terminals 11 and 12 are in contact. It can be seen that the voltage applied to the path is much larger, and the efficiency of the circuit is worsening.

  On the other hand, when the current supply to the wiring pattern 6 is started at time Ta in the substrate inspection apparatus 1 of FIG. 1 from the lines L1 and L2 of FIG. 2, the first and second voltage measurements of the wiring pattern 6 are started. The voltage at the contact portion with the terminals 11 and 12 is instantaneously stabilized, and the voltage difference between two points of the wiring pattern 29 where the first and second voltage measurement terminals 24 and 25 are in contact immediately after the start of current supply can be measured. You can see that Further, since the voltage of the contact portion between the second voltage measurement terminal 25 and the second voltage measurement terminal 25 of the wiring pattern 29 is held at the ground potential, the first and second voltage measurement terminals 24 and 25 are It can be seen that the voltage difference between the two points of the wiring pattern 29 in contact is substantially equal to the output voltage of the current supply unit 26, and the efficiency of the circuit is good.

  As a modification of the configuration according to the above-described embodiment, if the terminal 23 and the terminal 25 can be stabilized at the same potential and a constant potential level, the potentials of these terminals 23 and 25 are set to other than the ground potential. It may be held at a predetermined reference potential. For example, a bias voltage may be applied to the wiring pattern 29 and the conductive path 32.

It is a figure showing composition of a substrate inspection device concerning one embodiment of the present invention. It is a graph which shows the voltage transition of the 1st and 2nd voltage measurement terminal when measuring the voltage between two points on a wiring pattern using the board | substrate inspection apparatus of FIG. 1, and the conventional board | substrate inspection apparatus. It is a figure which shows the structure of the conventional board | substrate inspection apparatus.

Explanation of symbols

  21 Board inspection device, 22 1st current supply terminal, 23 2nd current supply terminal, 24 1st voltage measurement terminal, 25 2nd voltage measurement terminal, 26 Current supply part, 26a, 26b Output part, 27 voltage Measurement unit, 27a, 27b Voltage introduction unit, 28 Voltage stabilization means, 29 Wiring pattern, 31, 32 Current supply conductive path, 33, 34 Voltage measurement conductive path, 35-38 Switching element, 41 Operational amplifier, 42 Ammeter.

Claims (3)

A board inspection apparatus for inspecting electrical characteristics of a board having a plurality of wiring patterns,
First and second current supply terminals that are in contact with the wiring patterns at positions separated from each other in any of the plurality of wiring patterns;
First and second voltage measurement terminals that are in contact with the wiring pattern at positions separated from each other in a section sandwiched between the first current supply terminal and the second current supply terminal in any one of the wiring patterns. When,
A current supply unit configured to flow a current from the first current supply terminal side to the second current supply terminal side to the one of the wiring patterns via the first current supply and the second current supply terminal; ,
A voltage between two points of any one of the wiring patterns with which the first voltage measurement terminal and the second voltage measurement terminal are brought into contact with each other via the first voltage measurement terminal and the second voltage measurement terminal. A voltage measurement unit to measure,
Voltage stabilization means;
With
Of the first voltage measurement terminal and the second voltage measurement terminal, the second voltage measurement terminal is in contact with any one of the wiring patterns on the downstream side of the current,
The voltage stabilization means is electrically connected to the second voltage measurement terminal, and stabilizes the voltage at the contact portion between the second voltage measurement terminal and the second voltage measurement element of any one of the wiring patterns. A substrate inspection apparatus characterized by being made to perform. The board inspection apparatus according to claim 1,
A substrate inspection apparatus, wherein the voltage stabilizing means includes an operational amplifier. The substrate inspection apparatus according to claim 2,
The positive-side and negative-side output units for supplying current from the current supply unit are connected to the first current supply terminal and the second current supply terminal via positive and negative current supply conductive paths. Each electrically connected,
The positive and negative voltage introduction sections for voltage measurement of the voltage measurement section are the first voltage measurement terminal and the second voltage measurement terminal via positive and negative voltage measurement conductive paths. And each is electrically connected,
The operational amplifier has an output terminal connected to the second current supply terminal side and a non-inverting input terminal connected to the negative output section side of the current supply section. A board inspection apparatus characterized by being inserted in a conductive path and having an inverting input terminal electrically connected to the second voltage measurement terminal.

Images