TWI621863B - Substrate inspection apparatus and substrate inspection method - Google Patents

Abstract

A method for inspecting a substrate, in which an electrical characteristic value is measured by passing an electric current to a conductor pattern formed on a circuit substrate through an inspection probe, and whether or not the circuit substrate is good is determined based on the measurement value of the electrical characteristic value, and the measurement value is within an allowable range It is judged as good in the case, repeated measurement when it is not judged as good, and judged as bad when the number of measurement times reaches the upper limit, and when the first measurement value deviates from the allowable range, the inspection is changed. The second measurement is performed in the direction of the probe current. When the second measurement value deviates from the allowable range, the deviation between the first measurement value and the second measurement value is measured. The direction of the current at the time when the difference is small is measured for the third and subsequent measurements.

Description

Substrate inspection device and substrate inspection method

The invention relates to a substrate inspection device and a substrate inspection method for inspecting the electrical conduction state or insulation state of a conductor pattern of a circuit substrate.

When inspecting an electrically conductive state or an insulated state such as a disconnection or a short circuit of a conductor pattern of a circuit substrate such as a printed circuit board, the following steps are performed by making the inspection probes abut on the exposed portions of both ends of the conductor pattern Measure the electrical characteristics such as the resistance value between the inspection probes by applying a current between the inspection probes or applying a voltage between the two conductor patterns, and check the conduction or insulation state based on the measured values.

In this case, the contact state between the inspection probe and the conductor pattern may affect the measured value. In particular, in recent years, requirements for quality (small variation in resistance value) have become higher due to miniaturization, and the influence of the contact state on the measured value has become a problem.

In order to solve the effect of such a contact state, Patent Document 1 discloses the following: When measuring the resistance value of a conductor pattern, etc., repeatedly measure the parameters until the measurement is abnormally continuous due to poor contact of the inspection probe, etc. When L (L is a natural number of 2 or more) occurs, the number of measurements has reached M (M is a natural number of L or more), and consecutive N (N is a natural number of 2 or more and less than M) The measured value of the parameter measured abnormally falls within the allowable range Either of the conditions is earlier.

According to this method, it is described that when a measurement abnormality such as a disconnected state is not detected and there is little variation in the measurement value, the measurement process can be ended before the number of measurements reaches M times, thereby improving the measurement efficiency.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-151554

However, in the method described in Patent Document 1, it is described that the predetermined number of measurements is set to M times. When no measurement abnormality is detected and there is little change in the measured value, the measurement process can be terminated before reaching the M times. However, in this case, if the condition that the measurement value falls within the allowable range is not satisfied for N consecutive times, the measurement process cannot be completed.

The present invention has been made in view of the circumstances described above, and an object of the present invention is to reduce the influence of the contact state between the conductor pattern of the circuit board and the inspection probe and to perform the inspection quickly.

The substrate inspection method of the present invention measures an electrical characteristic value based on a current flowing to a conductor pattern formed on a circuit substrate through an inspection probe, and determines whether the circuit substrate is good or not based on the measured value of the electrical characteristic value. When the first measurement value deviates from the allowable range, change the direction of the current to the inspection probe and perform the second measurement. When the second measurement value deviates from the allowable range, determine the above. For the current direction when the difference between the first measurement value and the second measurement value that deviates from the allowable range is smaller, the third and subsequent measurements are performed.

The substrate inspection device of the present invention measures an electrical characteristic value based on a current flowing in a conductor pattern formed on a circuit substrate, and determines whether the circuit substrate is good or not based on the measured value of the electrical characteristic value, and includes: For the inspection probe, they are in contact with the conductor pattern; the switching mechanism is used to switch the direction of the current flowing between the inspection probes; and the inspection determination unit compares the measured value with a predetermined threshold value. When the above-mentioned measurement value is within the allowable range, the above-mentioned circuit board is judged to be good; and the current direction control unit, when the first measurement value is not judged to be good by the above-mentioned inspection and judgment unit, changes to The switching mechanism is controlled for the direction of the current of the inspection probe, and when the second measurement value is not judged to be good by the inspection determination unit, the first measurement value is measured. The direction of the current when the measured value is smaller than the second deviation from the above-mentioned allowable range in the direction of the current is input to the switching mechanism.行 控制。 Line control.

When the measured value deviates from the allowable range due to poor contact of the inspection probe, etc., it is also possible to perform accurate inspection by reducing the influence of the contact state by performing two or more measurements. When the measured value is within the allowable range, the circuit board is judged to be good.

In the case where a plurality of measurements are performed, if the direction of the current is changed and the first measurement and the second measurement are performed, a difference occurs in the measured values. The reason is considered to be that a conductor and an insulator (for example, a contact portion) are mixed in an electric path in a state where the inspection probe and the conductor pattern are in contact with each other, so that an electric current can easily flow in any direction. When the measurement is performed repeatedly, the measurement value gradually converges to a specific value as the number of measurements is increased. Therefore, if the measurement is performed while the direction of the current is alternately switched, the measurement value gradually converges to a specific value, but a larger measurement value and a smaller measurement value are alternately measured. This measurement is performed while switching alternately, and it takes time before the measured value enters the allowable range.

In the present invention, the first two measured values are compared and the deviation tolerance range is determined. The measurement of the direction of the current when the measurement value with a smaller range difference value is performed after the third measurement, thereby making the measurement under the measurement conditions with a smaller effect of the contact state, so that it can reach the allowable range more accurately and quickly. Accordingly, the inspection time can be shortened.

The substrate inspection method of the present invention can also be set as follows: when the measurement value is within the allowable range, it is judged to be good; when it is not judged to be good, the measurement is repeated, and the number of measurements has reached the upper limit. In this case, it was judged as bad.

The substrate inspection device of the present invention may further include: a condition setting unit that sets an upper limit of the number of measurement times; and a repetitive control unit that repeatedly measures up to the above-mentioned measurement times when it is not judged to be good by the inspection determination unit. When the upper limit is reached, and when the inspection determination unit does not determine that it is good and the number of measurements has reached the upper limit, it determines that it is defective.

According to the present invention, the influence of the contact state between the conductor pattern of the circuit board and the inspection probe can be reduced, and inspection can be performed quickly.

1‧‧‧circuit board

2‧‧‧ conductor pattern

11‧‧‧ substrate inspection device

11'‧‧‧ Substrate Inspection Device

12‧‧‧DC current source

12'‧‧‧DC voltage source

13‧‧‧ Inspection probe

14‧‧‧Switch (switching mechanism)

15‧‧‧Potential detection department

15'‧‧‧potential‧current detection section

16‧‧‧Control Department

17‧‧‧Display

23‧‧‧Condition Setting Department

24‧‧‧ Inspection and Judgment Department

25‧‧‧Repeat Control Department

26‧‧‧Current direction control unit

27‧‧‧ Ministry of Communications

R0‧‧‧Threshold

Ra‧‧‧Threshold

Rb‧‧‧Threshold

S1 ~ S16‧‧‧step

FIG. 1 is a flowchart showing a method for inspecting the continuity of a circuit board according to the first embodiment of the present invention.

Fig. 2 is a block diagram showing an inspection apparatus for a circuit board according to the first embodiment of the present invention.

FIGS. 3A and 3B show the number of measurements and measurements when the circuit board is inspected by the continuity inspection method according to the first embodiment, and when the current direction is alternately switched while the measurement is being performed, and the continuity inspection is performed on the circuit board. A graph of the relationship of values.

FIG. 4 is a graph showing the relationship between the number of measurements and the measured value in the case where the circuit board is continuously inspected with a current flowing in the same current direction.

FIG. 5 is a flowchart showing a method for inspecting the insulation of a circuit board according to a second embodiment of the present invention. Illustration.

Fig. 6 is a block diagram showing an inspection apparatus for a circuit board according to a second embodiment of the present invention.

FIG. 7A and FIG. 7B show the number of measurements and measurements when the circuit board is inspected by the insulation inspection method according to the second embodiment, and when the current direction is switched alternately when the measurement is performed, and when the insulation inspection is performed on the circuit board. A graph of the relationship of values.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Substrate inspection device]

The substrate inspection device 11 of the first embodiment is a person who conducts a conduction inspection of the conductor pattern 2 of the circuit substrate 1. As shown in FIG. 2, the substrate inspection device 11 includes a DC current source 12 that generates a specific DC current, and a pair of inspection probes 13, These are in contact with both ends of the conductor pattern 2 exposed on the circuit substrate 1; a switch (switching mechanism) 14 is provided between the inspection probe 13 and the DC current source 12; and a potential detecting section 15 for The detection unit 13 detects the potential between the inspection probes 13; the control unit 16 controls the energization of the inspection probes 13 and determines whether the circuit board 1 is good; and the display unit 17 displays the determination results.

As the inspection probe 13, for example, a two-terminal terminal is used, and each probe is brought into contact with the conductor pattern 2 for detection. The potential detection section 15 detects the potential between the inspection probes 13 when the two inspection probes 13 are in contact with both ends of the conductor pattern 2 of the circuit board 1 and a fixed current flows from the DC current source 12. The potential is subjected to A / D (Analog to Digital) conversion and transmitted to the control unit 16 as a digital signal.

The switch 14 has the following two functions: turning on (ON) and turning off (OFF) the connection between the DC current source 12 and the inspection probe 13 to start or stop the energization of the inspection probe 13; and When the DC current source 12 and the inspection probe 13 are connected, the two inspection probes 13 The direction of current flow is switched. However, in the present invention, these two functions may be provided separately.

The control unit 16 includes a CPU (Central Processing Unit, central processing unit), a memory, and the like, controls the DC current source 12 and the switch 14, and performs a good or bad operation on the circuit board 1 according to the detection potential of the potential detection unit 15. The judges are provided with a condition setting unit 23 for setting various conditions, a check judging unit 24 for judging whether the circuit board 1 is good, an iteration control unit 25 for controlling iteration of measurement, and a current for controlling the direction of current during measurement. A direction control unit 26 and a communication unit 27 that performs data communication with each unit.

The condition setting unit 23 may set a constant current value generated by the DC current source 12, a threshold value for determining whether the measurement value is a permissible range, an upper limit of the number of measurements, and the like in the inspection and determination unit 24. The constant current value, the threshold value, and the upper limit of the number of measurements are set to appropriate values according to the characteristics of the circuit board to be inspected.

The inspection and determination unit 24 extracts data (potential) sent from the potential detection unit 15, calculates a resistance value based on a relationship with a constant current value set in advance to the DC current source 12, and sets the resistance value and a threshold value. (The maximum allowable resistance value when the on-state is good) is compared, and whether or not the circuit board 1 is good is determined based on which of the smaller comparison results.

The repeated control unit 25 performs control in such a manner that, when it is not judged as being good by the inspection determination unit 24, measurement is repeated a specific number of times under specific conditions.

The current direction control unit 26 controls the direction of the current when the measurement is repeatedly performed by the control of the repeated control unit 25.

The details of the above control by the control unit 16 will be described in the following description of the substrate inspection method.

[Substrate inspection method]

A method for inspecting a substrate will be described with reference to the flowchart of FIG. 1.

When conducting the continuity inspection of the circuit board 1, the inspection probe 13 is brought into contact with both ends of the conductor pattern 2. First, the state of the current flowing to the conductor pattern 2 is set to either direction (S1: Current direction initial setting).

Next, the number of measurements i is set to 1 (S2), and the power is supplied to the inspection probes 13 by setting the changeover switch 14 to ON (S3). If a specific current flows to the conductor pattern 2 between the inspection probes 13, the potential between the inspection probes 13 is detected by the potential detection section 15 (S4), and the current is blocked after detecting the potential (S5) . Then, a resistance value is calculated based on the potential and a current value set in advance for the DC current source 12 (S6). Alternatively, in S6, a current detection mechanism may be separately prepared, and the resistance value may be calculated using the current value actually measured during energization.

A potential is detected by flowing a current through the conductor pattern 2 between the inspection probes 13, and a resistance value is calculated based on the potential, and the procedure until the resistance value is compared with the threshold R0 in the next step S7 is set to one measurement. , Set the resistance value calculated during this period as the measured value Ri (i = 1 ~ n).

It is judged whether the measured value Ri (i = 1 ~ n) is below the threshold R0 set in advance (S7), and it is judged as Ri In the case of R0, that is, when it is determined that the measured value Ri is within the allowable range, the circuit board 1 is determined as "good" (S8).

It is not determined in S7 that the measured value Ri is below the threshold R0 (Ri In the case of R0), it is judged whether the measurement is the n-th measurement (S9), and when it is judged as the n-th time, the circuit board is judged as "defective" (S10). The n-th value is set in advance by the condition setting unit 23. The n-th measurement means that the measured value Ri has not reached the threshold R0 or less during the period up to this time, and the circuit has not reached the threshold R0 even if the measured value Ri reaches the upper limit n times. The substrate 1 was determined to be defective.

When it is determined in S9 that the number of measurement times is not the nth time, it is determined whether the measurement is the nth time. In the first measurement (S11), when it is judged that it is the first time, the current direction control unit 26 operates the switch 14 to perform the current direction switching process (S12). When it is not determined that the measurement is the first time in S11, the process proceeds to the next step S13.

When it is not determined as the first measurement in S11, it is determined whether it is the second measurement (S13). When it is judged that it is the second measurement, the first measurement value (resistance value) R1 is compared with the second measurement value (resistance value) R2 to determine whether the first measurement value R1 is smaller than the second measurement value. The next measured value is R2 (S14). When it is not determined as the second measurement in S13, the process proceeds to the next step (S15).

When it is determined in S14 that the first measurement value R1 is smaller than the second measurement value R2, the current direction control unit 26 operates the switch 14 to complete the current direction switching process (S16). When it is not determined in S14 that the first measurement value R1 is smaller than the second measurement value R2, the process proceeds to the next step without switching the current direction (S15). That is, when the first measurement value is small (when the difference between the first measurement value and the threshold R0 is smaller than the difference between the second measurement value and the threshold R0), Select the direction of the current when the first measurement is performed, and when the second measurement is smaller than the first measurement (the difference between the second measurement and the threshold R0 is less than the first measurement and threshold In the case of the difference between the values R0), the current direction when the second measurement is performed is selected, and the conditions (current direction) when the inspection after the third time is performed are selected.

In S15, the measurement control unit 25 counts up the number of measurements i, and repeats the measurement from S3 again. During this period, the inspection probe 13 is kept in contact with the conductor pattern 2 of the inspection target, and only the changeover switch 14 is controlled.

In this series of processes, the inspection ends when the measured value Ri is determined to be less than the threshold R0 in S7 and is judged to be good in S8; and even if the measurement is repeated, the measured value Ri does not become the threshold. The value is below R0, so although the number of measurements has reached the upper limit n times in S9, It was also judged to be bad in S10. When the inspection is completed because it is judged to be good, for example, when the first measurement is judged to be good, the inspection is completed by one measurement, and at the time point when it is judged to be good without waiting for the number of measurements i to be n, the inspection is performed. End.

As for the direction of the current at the time of measurement, it is determined whether the first measurement value R1 is smaller than the second measurement value R2 at the time point when the second measurement is completed from the beginning (S14), and the first measurement is determined. When the value R1 is smaller than the second measurement value R2, the current direction is switched in order to use the current direction at the first measurement (S16). When it is not judged that the first measurement value R1 is small, Without changing the current direction, in other words, the subsequent measurement was performed while maintaining the current direction at the time of the second measurement. That is, the measurement after the third time is performed in the current direction at the time when the value of the difference from the allowable range in the two measured values is smaller. When the measurement is performed while alternately switching the direction of the current each time the measurement is performed, the measurement value gradually converges to a specific value, but the larger measurement value and the smaller measurement value are alternately measured. Therefore, it takes time before the measured value becomes the threshold value or less, but the measured value becomes the reference value R0 or less at an earlier time point by the inspection method of this embodiment.

FIG. 3A and FIG. 3B show the number of measurements n as 10, and the change of the measurement value generated by repeated measurement is shown in a graph. FIG. 3A shows a case where the first measured value is larger than the second measured value, and FIG. 3B shows a case where the second measured value is larger than the first measured value. In each figure, the dotted line indicates the case where the measurement is performed while the direction of the current is alternately changed every time the measurement is performed. The solid line indicates that, as in this embodiment, the current direction is switched during the first measurement and the second measurement, but after the third measurement, the comparison between the first and second measurements is performed. The measurement is performed in the direction of the current when a small measurement value, that is, a measurement value with a small difference from the allowable range. The upper part of each figure shows the change of the current direction when the current direction is checked while the current direction is switched alternately, and the lower part shows how the current The change of the direction of the current caused by the state inspection method.

In the inspection method of this embodiment, in the example shown in FIG. 3A, the second measurement value is smaller than the first measurement value. Therefore, the measurement is performed in the same current direction (-direction) as in the second measurement. Measurement after the third time. In the example shown in FIG. 3B, the first measurement value is smaller than the second measurement value. Therefore, the measurement after the third time is performed in the same current direction (+ direction) as the first measurement.

As shown in FIG. 3A and FIG. 3B, it can be seen that compared with the case where the measurement is performed while the current direction is alternately switched every time the measurement is performed (the case indicated by the dotted line), The earlier time point (the fifth measurement in the case of FIG. 3A and FIG. 3B) is lower than the threshold R0, that is, the measured values up to the first two are compared, and the tolerance range of the deviation from the measured value is determined by using the measurement The direction of the current when the difference is a small measured value, and then a current is passed in the direction of the current to check (in the case of a solid line).

Incidentally, FIG. 4 shows the change of the measured value when the current is passed in the same direction (+ direction in the example shown in FIG. 4) without changing the direction of the current at all, and the same conductor pattern is repeatedly measured. In this case, as the number of measurements increases, the measurement value decreases, but it takes time before it becomes less than the threshold R0.

By repeating the measurement during the continuity inspection of the circuit board, the influence of the contact state of the inspection probe 13 and the like can be reduced to accurately measure the resistance value of the conductor pattern 2. In this case, the first two switching currents The direction of the current is measured by measuring the current direction when the difference between the first and second measurement values is smaller than the allowable range (threshold value) after the third measurement. It can be set to a threshold value R0 or lower at an earlier point in time, thereby reducing the inspection time.

Furthermore, in the above embodiment, the substrate inspection method and substrate inspection of the present invention are used. The device is used for continuity inspection for inspecting the disconnection of a conductor pattern, etc. by contacting the inspection probe with both ends of the conductor pattern, but it can also be used to inspect the conductor pattern between the inspection probe and the individual conductor pattern. The present invention is applied to an insulation inspection for an insulation state inspection.

5 and 6 show a second embodiment in which the present invention is applied to insulation inspection. FIG. 5 is a flowchart of a substrate inspection method for insulation inspection, and FIG. 6 is a system block diagram of a substrate inspection apparatus.

In the substrate inspection apparatus 11 ′ of the second embodiment, a DC voltage source 12 ′ is provided instead of the DC current source 12 of the substrate inspection apparatus 11 of the first embodiment, and a potential and current detection unit 15 ′ is provided. Instead of the potential detection section 15. Further, it is configured as follows: the potential between the inspection probes 13 when a voltage is applied between the inspection probes 13 in contact with the two conductor patterns 2 by the potential and current detection unit 15 'from the DC voltage source 12', respectively And current. Regarding the other structures, the substrate inspection apparatus of the first embodiment is the same as that of the substrate inspection apparatus of the first embodiment except for the parts that are changed corresponding to the DC voltage source 12 'and the potential and current detection unit 15' (explained in the following insulation inspection method). 11 is the same, and common parts are denoted by the same reference numerals, and descriptions thereof are omitted.

In the case of using the substrate inspection apparatus 11 'to perform an insulation inspection of the circuit board 1, first, a voltage (and a direction of a current flowing through the application of a voltage) applied between the conductor patterns 2 by the switch 14 is set in advance ( S1 '). Next, the number of measurements i is set to 1 (S2), and a voltage (current) is applied between the inspection probes 13 by setting the changeover switch 14 to ON (S3 '). When a specific voltage is applied between the two conductor patterns 2 contacted by the inspection probe 13, the potential and current between the two conductor patterns 2 are detected by the potential · current detection unit 15 ′ (flow from the high potential side to the low level) Current on the potential side) (S4 '). After detecting the potential and current, stop applying voltage (S5'). Then, a resistance value (measured value Ri) is calculated based on the potential and the current (S6).

In the case of the insulation inspection, a measured value (resistance value) within a specific allowable range is obtained when the substrate is normal. If the lower limit value of the allowable range is set to Ra and the upper limit limit value is set to Rb, then when the substrate is normal, it becomes Ra. Ri Rb. Therefore, the threshold Ra of the lower limit and the threshold Rb of the upper limit are set in advance, and it is determined whether the measured value Ri is within the allowable range (S7 '), and it is determined as the allowable range (Ra Ri In the case of Rb), it is judged as good (S8).

Thereafter, steps S9 to S15 are the same as those in the first embodiment described above. In S15, the number of measurements i is incremented and the steps from S3 'are repeated again.

In this insulation inspection, the inspection probe 13 is brought into contact with the two conductor patterns 2 respectively, and a voltage is applied across the conductor patterns 2 to thereby inspect the insulation state between the conductor patterns 2. In addition, since a voltage is applied from the DC voltage source 12 ', in the step of switching the current direction of S12 and S16, the direction of the current flowing is switched by switching the direction of application of the voltage. That is, in this insulation inspection, a voltage is applied to measure the current flowing from the high potential side to the low potential side, and the inspection is performed by changing the direction of the current flowing by changing the application direction of the voltage.

At the time of the insulation inspection, the range between the threshold value Ra and the threshold value Rb (Ra Ri In the case of Rb), it is judged to be good. When it is not judged to fall into the allowable range, the measurement is performed by changing the direction of the voltage between the first measurement and the second measurement to determine any smaller measurement value. That is, the direction of the current flowing when the measured value with a small difference from the allowable range is measured in the direction of the subsequent measurement.

If the resistivity of the material dependent on the conductor patterns arranged side by side is set to ρ, the length of the conductor pattern (space) is set to L, and the side wall area of the conductor pattern between the conductor patterns is set to A, then the side by side The insulation resistance value Rx between the conductor patterns is represented by Rx = ρ‧L / A.

The threshold Ra of the lower limit and the threshold Rb of the upper limit may be determined in consideration of the deviations of L, A, and ρ. Alternatively, the measured values of the insulation inspection may be accumulated and determined based on statistical analysis.

FIG. 7A and FIG. 7B are graphs showing transitions of measured values of insulation inspection, and The insulation inspection method of the second embodiment inspects a circuit board, and compares it with the case where the current direction is alternately switched and the insulation inspection is performed on the circuit board each time a measurement is performed, and a curve showing the relationship between the number of measurements and the measurement value is shown. Illustration. In FIG. 7A and FIG. 7B, the second measurement value is less than the first measurement value, but due to the influence of contact resistance and the like, the resistance value is higher than the threshold (Ra, Rb). Furthermore, in FIG. 7A, the measurement is repeated by using the current direction of the second time when the measured value is small, that is, the current direction when the value of the difference from the allowable range is smaller than the value of the second time of the first measurement. Based on the measured value falling within the range of the upper limit threshold Rb and the lower limit threshold Ra, that is, within the allowable range, it is determined that the insulation state is good. When the measurement is performed while the current direction is alternately switched, as shown by the dotted line, it takes a period of time before reaching the allowable range.

On the other hand, FIG. 7B shows an example of performing an insulation inspection on a substrate having a short circuit between conductor patterns and having poor insulation. In the case of FIG. 7B, immediately after the barriers such as contact resistance are eliminated in the initial stage of the measurement, it becomes a short-circuit resistance value (resistance value lower than the lower limit threshold Ra), and it is determined that the insulation is poor.

The case of this insulation inspection is the same as the case of the continuity inspection. When the smaller measurement value between the first measurement value and the second measurement value is used, the difference between the measured value and the allowable range is determined. In the case of a small measurement value, the current direction is measured after the third time, so that it can be judged as good or not at an earlier stage.

In the case of the continuity check in the first embodiment described above, the allowable range of the measured value is determined using a threshold value, and within the allowable range means that the measured value is below the threshold value. On the other hand, in the case of insulation inspection in the second embodiment, the allowable range is the range between the upper limit threshold value and the lower limit threshold value. If the measured value is within the allowable range, the measured value becomes the upper limit. Within the threshold of the lower limit.

Furthermore, in the case of continuity inspection, a threshold value of the upper limit and a threshold value of the lower limit can also be set in advance. When the measured value is between the threshold value of the upper limit and the threshold value of the lower limit, it is judged as a good product. .

Furthermore, in any of the embodiments, the resistance value is calculated based on the potential and current between the inspection probes 13 and whether the circuit board is good or not based on the resistance value. However, in the first embodiment, for example, The value of the potential itself detected between the probes 13 is checked to determine whether it is good or not. In the present invention, the potential and resistance value are included as the electrical characteristic value.

Claims (4)

A substrate inspection method comprising measuring an electrical characteristic value based on a current flowing to a conductor pattern formed on a circuit substrate through an inspection probe, and determining whether or not the circuit substrate is good based on a measurement value of the electrical characteristic value. When the first measurement value deviates from the allowable range, change the direction of the current to the inspection probe to perform the second measurement. When the second measurement value deviates from the allowable range, determine The direction of the current when the value of the difference between the first measurement value and the second measurement value that deviates from the allowable range is smaller is the measurement direction of the third and subsequent measurements. For example, the substrate inspection method of claim 1, in which the case is judged to be good when the above-mentioned measurement value is within the allowable range, and it is repeatedly measured when it is not judged to be good, and when the number of measurement times reaches the upper limit, the judgment is bad. A substrate inspection device that measures an electrical characteristic value based on a current flowing in a conductor pattern formed on a circuit substrate and determines whether the circuit substrate is good or not based on the measured value of the electrical characteristic value, and includes: a pair of The inspection probes are in contact with the conductor pattern; the switching mechanism is used to switch the direction of the current flowing between the inspection probes; the inspection determination unit compares the measured value with a predetermined threshold value, When the measured value is within the allowable range, the circuit board is judged to be good; and when the current direction control unit is not judged to be good by the inspection and judgment unit at the first time, the circuit board is changed to The direction of the current direction of the inspection probe controls the switching mechanism, and when the second measurement value is not judged to be good by the inspection determination unit, it is assumed that the first measurement value and the In the second measurement value, the switching mechanism is configured to perform the direction of the current when the value of the difference from the allowable range is smaller than the measurement value. control. For example, the substrate inspection device of claim 3 includes: a condition setting unit that sets an upper limit of the number of measurement times; and a repetition control unit that repeatedly measures up to the above-mentioned measurement times when it is not judged to be good by the inspection determination unit. Until the upper limit is reached, and when the inspection determination unit does not determine that it is good and the number of measurement times reaches the upper limit, it determines that it is defective.