TWI636264B - Non-contact substrate inspection device and inspection method - Google Patents

Abstract

The present invention relates to a non-contact substrate inspection device and an inspection method thereof, which include a gain adjustment section that amplifies detection signals of a reference sensor and a signal sensor that are all arranged in a non-contact manner on a wiring pattern having a divergent part A determination signal is generated by amplifying the difference between the detection signals whose gains have been adjusted by a differential amplifier, and the predetermined reference value is divided by the determination signal to obtain a change rate. The change rate is compared with a preset setting. The limit values are compared to make a bad judgment.

Description

Non-contact substrate inspection device and inspection method

The present invention relates to a non-contact type substrate inspection device that performs non-contact inspection of a wiring pattern having a branched portion in a non-contact manner.

Conventionally, there is known an inspection device that applies and detects an AC inspection signal to a plurality of wiring patterns formed on a substrate in a non-contact manner, that is, adjacent to and is capacitively coupled to the wiring patterns to check the breakage of the wiring patterns. Poor wiring or insulation. For example, Patent Document 1: Japanese Patent Laid-Open No. 2000-019213 discloses an inspection device that allows a probe to contact one end of a plurality of wirings provided on a substrate to be inspected, and selectively switches the inspection object as an inspection target. Wiring pattern, with a sine wave or pulse wave-shaped inspection signal applied on one side, and a capacitively coupled sensor placed above the other end to detect the transmitted inspection signal as a detection signal, and then based on this detection signal Size, perform disconnection inspection and insulation inspection.

The inspection device disclosed in the aforementioned Patent Document 1: Japanese Patent Laid-Open No. 2000-019213 is provided with a rod-shaped sensing electrode so as to be adjacent to a direction in which a plurality of wiring patterns traverse a substrate. The detection signal applied by the probe and transmitted to the wiring pattern of the inspection object is detected by capacitive coupling as a detection signal. In the case where the wiring pattern to be inspected is an independent wiring (independent network) without a divergent portion, a probe as a power supply electrode and a sensing electrode as a power receiving electrode may be arranged at both ends of the wiring as an inspection object, And based on whether there is a transmission check signal 定 itis bad.

On the other hand, in a wiring pattern (branching network) having a plurality of branched portions, even if one of the plurality of wiring patterns after the branching is in a state where the inspection signal is not transmitted due to a broken wire or the like Since the other wiring patterns after the divergence will still pass the inspection signal, the difference between the detected inspection signal and the signal level of the good product is small, and a correct bad judgment cannot be made.

Therefore, an object of the present invention is to provide a non-contact type substrate inspection device and an inspection method thereof. For a wiring pattern having a divergent portion as an inspection object, in addition to a signal sensor configured to detect a detection signal by capacitive coupling, At least one reference sensor that is capacitively coupled to the branched position is also configured, and the respective detection signals are compared to perform a bad determination.

A non-contact substrate inspection apparatus according to an embodiment of the present invention includes a power supply unit that supplies an inspection signal of an alternating current or a pulse to a wiring pattern formed on a substrate and having at least one branched portion in the middle; a reference A sensor, which is adjacent to and above the vicinity of the divergence of the wiring pattern, and is capacitively coupled in a non-contact manner; a signal sensor, which is adjacent to the vicinity of an end of the wiring pattern after the divergence of the wiring pattern And is capacitively coupled in a non-contact manner; the detection signal processing unit holds a first detection signal detected by the reference sensor from the wiring pattern supplied with the inspection signal, and the signal sensor detects from the wiring pattern The respective peaks of the second detection signals are uniformly determined at the same time, the difference between the first detection signal and the second detection signal is obtained, and the difference is amplified and output as a determination signal; and the defect determination unit, which uses Divide the determination signal by a predetermined reference value to obtain a rate of change, and compare the rate of change with a preset threshold Compare without proceeding Good judgment.

In addition, according to the substrate inspection method of the embodiment of the present invention, a reference sensor and a signal sensor are used which are arranged in a non-contact manner on a wiring pattern formed on a substrate and have at least one branched portion in the middle. Those who perform capacitive disconnection inspection for a broken wire, the substrate inspection method includes the following: adjusting the gain by outputting a detection signal with the same peak output from the reference sensor and the signal sensor to a normal wiring pattern, The reference sensor is arranged above the wiring pattern in the vicinity of the branched portion in a non-contact manner above the branch pattern to detect the first detection signal, and is arranged in a non-contact manner above the end of the wiring pattern after the branching in the branched region. The signal sensor detects the second detection signal, maintains the respective peak values of the first detection signal and the second detection signal, outputs the peak values at the same time, performs a difference operation on each of the peak values, and calculates the calculated voltage. Amplify the difference to generate a judgment signal, divide the judgment signal by a predetermined reference value to obtain a change rate, and change the change. The rate is compared with a pre-set threshold, and a bad judgment is made.

1‧‧‧Inspection device

2‧‧‧ reference sensor

3‧‧‧Signal Sensor

4‧‧‧ Detection Signal Processing Department

5‧‧‧Defect determination department

6‧‧‧Control Department

7‧‧‧ Operation Processing Unit (CPU)

8‧‧‧Power Supply Department

9‧‧‧ Inspection signal supply department

11, 12‧‧‧ detection signal

13‧‧‧Display

14‧‧‧ Probe

15‧‧‧ disconnection

20‧‧‧ Detection Signal Processing Department

21‧‧‧Peak hold circuit

22‧‧‧ Differential Amplifier

23‧‧‧A / D Conversion Department

24, 24a‧‧‧ Detection signal

25‧‧‧Gain adjustment section

26, 27‧‧‧ Judgment signals

30‧‧‧ Differential amplifier gain setting section

31, 32‧‧‧Gain Variable Amplifier (VGA)

100‧‧‧ substrate

101, 104‧‧‧wiring pattern (independent network)

102, 103‧‧‧wiring pattern (divergent network)

102a, 103a ‧‧‧ divergent parts

105‧‧‧wiring pattern (circuit pattern)

P11‧‧‧peak

P12‧‧‧peak

Vdiff‧‧‧ output signal

VR1, VR2‧‧‧ Variable resistor (digital potentiometer)

Vsig‧‧‧ detection signal

FIG. 1 is a diagram showing a conceptual configuration of a non-contact type substrate inspection apparatus of the present invention.

Fig. 2 is a diagram showing a configuration example of a detection signal processing unit according to the first embodiment.

FIG. 3 is a graph showing a relationship between an output voltage and a wiring pattern detected from a normal wiring pattern by a sensor.

FIG. 4 is a graph showing a relationship between an output voltage and a wiring pattern detected by a sensor from a wiring pattern having a bad disconnection.

FIG. 5 is a flowchart showing the steps of conceptually determining a bad decision.

FIG. 6 is a diagram showing a configuration example of a detection signal processing section of a non-contact type substrate inspection apparatus according to a second embodiment.

FIG. 7 is a diagram showing a specific configuration example of the gain adjustment section shown in FIG. 6.

FIG. 8 is a diagram showing a signal level of a sensor output after a gain is adjusted by a gain adjustment section.

FIG. 9A is a diagram showing an output of a differential amplifier in a case where a detection signal processing section is mounted.

FIG. 9B is a diagram showing an output of a differential amplifier in a case where a detection signal processing section is not installed.

FIG. 10 is a flowchart for explaining adjustment for performing non-contact inspection.

FIG. 11 is a flowchart for explaining the operation sequence of the non-contact inspection.

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

FIG. 1 is a diagram showing a conceptual configuration of a non-contact type substrate inspection apparatus of the present invention. This non-contact type substrate inspection apparatus 1 (hereinafter, referred to as an inspection apparatus) can be applied to a substrate (inspected workpiece) to be inspected, but is not limited to a printed circuit wiring substrate. For example, it can be applied to a flexible substrate or a multilayer wiring substrate. Inspection of various electrical wiring such as liquid crystal packaging substrates. In the following description, these are collectively referred to as "substrates". In addition, as shown in FIG. 1, the wiring patterns formed on the substrates 100 are mixed to form wiring patterns (as branch networks) 102, 103, which have branched portions on the way and branch from a plurality of wirings to one another Wiring patterns 105 (as independent networks) 101 and 104 without branching portions. In FIG. 1, as the wiring pattern, the four-divided branch network 102 and the two-divided branch network 103 are illustrated, but the number of branches is not limited.

The inspection device 1 includes a sensor section including a reference sensor 2 and a signal sensor 3, and a detection signal processing section 4 based on a detection signal 11 detected by the reference sensor 2 and the signal sensor 3. 12, generating a judgment signal 26 (27); an arithmetic processing unit (CPU) 7, which includes a defect judgment unit 5 for performing a good or bad judgment and a control unit 6 for the entire control device; and a display unit 13 which displays information related to the inspection Operation information or determination result; the power supply unit 8 that generates an inspection signal; and the inspection signal supply unit 9 that selectively applies an inspection signal to a wiring pattern of an inspection object. In addition, although not shown, the arithmetic processing unit 7 is equipped with a memory, and the memory system stores a program, a reference value, and a set value (gain, etc.) used for determination. In addition, in order to input and set various information, input devices such as a keyboard or a touch panel are also provided.

The reference sensor 2 and the signal sensor 3 are formed in the same rod shape with the same specifications, that is, using the same metal material, and the same electrode area, and have the same characteristics. Thereby, as long as the reference sensor 2 and the signal sensor 3 are opposed to the wiring pattern as the counter electrode at the same interval (distance between the electrodes), detection signals with the same peak value can be obtained. As shown in FIG. 1, the reference sensor 2 is configured to be capacitively coupled to one end of the branching networks 102 and 103 on the substrate 100 and adjacent to the wiring pattern branched from the branching portions 102 a and 103 a. In addition, the signal sensor 3 is arranged so as to be capacitively coupled to the wiring pattern adjacent to the other end side of the branch networks 102 and 103.

The power supply unit 8 generates an inspection signal of an AC wave or a pulse wave in a frequency band of about 20 KHz to 1 MHz, for example. In the present invention, since the detection of signals is performed by capacitive coupling, no DC inspection signal is used. The inspection signal supply unit 9 is provided with a plurality of probes 14, and the front ends of the probes 14 are in contact with the wiring patterns to be electrically connected within the entirety or the inspectable range. By following the instructions of the control section 6 The switching mechanism shown in the inspection signal supply section 9 selectively applies an inspection signal to an inspection object.

Next, a first embodiment will be described.

FIG. 2 shows a detailed configuration example of the detection signal processing section 4 of the first embodiment. The detection signal processing section 4 is composed of a peak hold circuit 21, a differential amplifier 22, and an A / D conversion section 23.

The peak hold circuit 21 is a well-known circuit structure for holding the peak value of the AC signal detection signal 11 output from the reference sensor 2 and the AC signal detection signal 12 output from the signal sensor 3 within a predetermined period. The differential amplifier 22 performs a difference operation to obtain a difference (voltage difference) between the detection signals respectively output by the reference sensor 2 and the signal sensor 3, amplifies the calculated difference, and outputs it as a detection signal 24. As long as this is the same detection signal, there will be no difference, so the differential amplifier outputs a detection signal of 0 (V). The A / D conversion section 23 is a known circuit that converts the analog waveform detection signal 24 output by the differential amplifier 22 into a digital signal.

FIG. 9A shows the characteristics of the output of the differential amplifier 22 when the detection signal processing unit 4 is mounted, and FIG. 9B shows the characteristics of the output of the differential amplifier 22 when the detection signal processing unit 4 is not mounted. The output value (1) of the differential amplifier is determined by the set gain.

Output value of differential amplifier = ((detection value of reference sensor)-(detection value of signal sensor)) × gain of differential amplifier (1)

If the detection signals 11 and 12 respectively output by the reference sensor 2 and the signal sensor 3 are directly input to the differential amplifier 22, the difference in time (phase) components of the signals is often amplified and output as detection signals. Therefore, if there is an offset at the time when the peaks are originally consistent, the difference will be amplified, and a detection signal 24 different from the desired result will be output. Therefore, for example, a peak hold circuit can be provided to obtain A case where a detection signal with time components removed is generated.

Specifically, as shown in FIG. 9A, when a pulse wave inspection signal is applied to the wiring pattern, a positive or negative peak value P11 is generated at the detection signal 11 of the reference sensor 2 by the effect of turning on or off, etc. , And the detection signal from the signal sensor 3 generates a positive and negative peak value P12.

In the case of a normal wiring pattern, although the peak value P11 and the peak value P12 are approximately the same value, a slight time difference may occur at the time of detection. Since the differential amplifier 22 amplifies the signal difference caused by the time difference, the output waveform becomes an unstable waveform with positive and negative peaks.

In contrast, as shown in FIG. 9B, when the peak hold circuit 21 is mounted, only the positive peaks P11 and P12 of the detection signals output from the reference sensor 2 and the signal sensor 3, respectively, are held. Therefore, when the input signal rises, although the output of the differential amplifier 22 will be generated in the time difference portion, it will become the same peak later, so the output of the differential amplifier 22 becomes 0 (V), so that the time component can be removed. If the detection result is obtained by using the period stabilized at 0 (V) as the data acquisition period T, the correct determination can be linked.

The defect determination unit 5 that performs the determination compares the change rate with a predetermined threshold value and determines whether the wiring pattern is good or bad. Specifically, a detection value detected using an adjustment wiring pattern or a good-quality wiring pattern is first set as a reference value. Next, the determination signal 26 output from the detection signal processing unit 4 is divided by the reference value to obtain a change rate [change rate = measured value / reference value]. Then, this change rate is compared with a preset threshold value, and a good or bad wiring pattern is determined according to a determination criterion (change rate> threshold value).

In addition, the threshold value is set based on the set reference value. As the center, there is a determination width having a width of an upper limit level and a lower limit level. Since the obtained detection signal is a small signal, there is an error when the noise from the outside overlaps or there is a difference in the distance between the reference sensor 2 and the signal sensor 3 and the wiring pattern. The threshold value is set to a value that takes the error into account.

Referring to the flowchart shown in FIG. 5, the determination of the good or bad of the wiring pattern in this embodiment will be described.

First, the reference sensor 2 and the signal sensor 3 that are capacitively coupled to the circuit pattern 105 as an inspection target detect the detection signal from an inspection signal of an AC or pulse wave flowing through the wiring pattern 105. These detection signals are transmitted to the detection signal processing section 4. Then, the determination signal 26 (measured value) output from the detection signal processing unit 4 is divided by the reference value to obtain a change rate (step S1).

For the wiring pattern to be inspected, the change rate is compared with a threshold value (change rate> threshold value) (step S2). If the change rate is less than or equal to the threshold value (No), the wiring pattern is judged to be good ( Step S3).

The defect determination unit 5 in the arithmetic processing unit 7 is in a normal state when the wiring pattern 105 shown in FIG. 1 is normal. As shown in FIG. 3, the reference sensor 2 and the signal sensor 3 output the same peak value and time. Consistent detection signals 11,12. Since the differential amplifier 22 has no voltage difference among the detection signals 11 and 12, it outputs 0V (detection signal 24). Therefore, the above-mentioned change rate is 0, and it is less than a predetermined threshold, and it is judged as a good product.

On the other hand, if the detection signal 24 is not 0V and the change rate is larger than the threshold value (Yes), it is determined that defective products such as disconnection are included (step S4). For example, when the wiring pattern 105 and one wiring pattern in the branch network 102 has a disconnection portion 15, as shown in FIG. 4, the detection signal of the reference sensor 2 decreases and a differential voltage is generated. Since the differential amplifier 22 amplifies this voltage difference and outputs it, the value of the detection signal detected from the independent networks 101, 104 and other branch networks 103 is 0V, and the detection signal obtained from the branch network 102 has a certain Voltage value. Therefore, the change rate obtained by dividing the detection signal by the reference value does not become zero. If this rate of change exceeds a threshold value, it is judged as bad. These determination results are displayed on the display unit 13 (step S5).

Furthermore, when detecting signals are obtained from the reference sensor 2 and the signal sensor 3, in order to prevent stray capacitance between wirings from being mixed into the inspection signal, it is preferable that an independent network or a branch network other than the inspection object is connected to the ground Potential.

In this embodiment, if the wiring pattern of the inspection object is normal, because there is no output difference between the reference sensor 2 and the signal sensor 3, a detection signal 24 of 0 is output from the differential amplifier 22, and the obtained change rate Since it is also 0, it can be judged as normal. On the other hand, if there is a disconnection part in the wiring pattern of the inspection object, the output difference between the reference sensor 2 and the signal sensor 3 increases, and the differential amplifier 22 amplifies the difference as a detection signal The output is obtained and a change rate other than 0 is obtained. As long as the change rate exceeds a predetermined threshold value, it can be judged as defective.

According to this embodiment, since the differential amplifier 22 only amplifies the voltage difference between the two detected signals, even if the gain is set to a large value, the output will not be saturated, even if the detection signal is output by a non-contact sensor. The difference is small, and bad detection can still be performed.

In addition, since the differential amplifier 22 is used, by the in-phase removal function of the difference operation, noise can be eliminated from the reference sensor 2 and the signal sensor 3 except for common overlap. In addition, because it has a peak hold circuit, it can simultaneously obtain the output of the reference sensor 2 and the signal sensor 3, and has anti-noise volume, reduce detection errors caused by external noise, and improve the detection signal obtained. Precision.

Next, a second embodiment will be described with reference to Figs. 1 and 6.

This embodiment is configured by a detection signal processing unit of the inspection device 1 and includes a gain adjustment unit and a differential amplifier gain setting unit that adjust the gain of the differential amplifier. In this embodiment, the configuration other than the detection signal processing unit is the same as the configuration of the first embodiment described above, and the same reference numerals are assigned, and detailed descriptions are omitted.

The detection signal processing section 20 shown in FIG. 6 includes a gain adjustment section 25, a peak hold circuit 21, a differential amplifier 22, a differential amplifier gain setting section 30, and an A / D conversion section 23.

The gain adjustment unit 25 is configured by a gain adjustment amplifier provided in each sensor. The gain adjustment amplifier of this embodiment uses, for example, two gain variable amplifiers (VGA) 31 and 32 to adjust the output of the reference sensor 2 and the signal sensor 3. The gain variable amplifiers 31 and 32 can obtain a gain proportional to the values of the variable resistors (digital potentiometers) VR1 and VR2 provided on the output side of the operational amplifier. The gain variable amplifiers 31 and 32 adjust the detection signals 11 and 12 detected by the reference sensor 2 and the signal sensor 3 so as to have the same output, so that the output of the differential amplifier 22 is minimized.

The gain detection amplifiers 31 and 32 amplify the detection signals output from the reference sensor 2 and the signal sensor 3, because in appearance, the sensitivity of the reference sensor 2 and the signal sensor 3 can be made. And the gain of the differential amplifier 22 is further increased, so that the result is equivalent to an increase in detection sensitivity. At this time, the differential amplifier gain setting unit 30 is switched and set by the control unit 6 so that the gain of the differential amplifier 22 matches the output values from the variable gain amplifiers 31 and 32.

The peak hold circuit 21 is controlled by an arithmetic processing section (control section) 7 At the same time, the detection signals 11 and 12 output from the gain adjustment unit 25 are output to the differential amplifier 22 while maintaining the peak value.

As shown in FIG. 8, in the case of a wiring pattern having no defects such as disconnection, the detection signals 11 and 12 output from each sensor have approximately the same peak value, but there are also noise or sensors. The detection signals 11 and 12 having different peaks due to the distance from the wiring pattern. For example, when the detection signal 12 is output low and a voltage difference is generated between the detection signal 11 and the output before the gain adjustment from the differential amplifier 22, the output has a voltage such as the detection signal 24a. value. However, by performing the gain adjustment described above, the detection signal 12 is amplified and amplified to the same peak value as the detection signal 11. If the adjusted detection signals 11 and 12 are input to the differential amplifier 22, a detection signal 24 of approximately 0 (V) is output.

Next, the gain adjustment performed before the inspection will be described with reference to FIGS. 1, 8, 9A, and 9B.

First, an inspection signal including an AC signal or a pulse wave is applied from the probe 14 to the adjustment wiring pattern for setting or the normal wiring pattern 105 (step S11).

Next, from the network 101, the detection signal Vsig detected by the signal sensor 3 is input to the variable gain amplifier 32. The gain variable amplifier 32 adjusts the gain with the variable resistor VR2 (step S12), and determines whether the amplified detection signal Vsig is within a predetermined reference value range (step S13). Moreover, the range of the reference value means the reference value ± the range of the reference value <the threshold value, and has a threshold value outside the reference value. Based on this determination, if it is within the range of the reference voltage (Yes), it is associated with the adjusted network 101, and the set gain and output voltage are stored in the memory provided in the arithmetic processing unit 7 (step S14).

Next, from the probe 14 toward the adjustment wiring pattern or The normal wiring pattern 105 applies an inspection signal including an AC signal or a pulse wave (step S15). Then, the detection signal detected by the reference sensor 2 is input from the network 101 to the variable gain amplifier 31. The variable gain amplifier 31 adjusts the variable resistor VR1 so that the value of the output signal (Vdiff) of the differential amplifier 22 becomes the smallest, so that the gain can be changed (step S16). Then, it is determined whether the value of the output signal (Vdiff) of the differential amplifier 22 is minimized by this adjustment (step S17). With this adjustment, if the output voltage (Vdiff) is the minimum value (Yes), it is associated with the adjusted network 101, and the minimum value of the set gain and the output voltage (Vdiff) is stored in the set in the arithmetic processing section 7. Memory (step S18).

This series of gain adjustment operations are performed on all the networks 101 to 104. After all the networks are finished (step S19), the adjustment operation is ended.

Next, the substrate inspection of the inspection device 1 after gain adjustment will be described with reference to the flowchart shown in FIG. 11.

A substrate 100 to be inspected is mounted on the inspection device 1, and the probe 14, the reference sensor 2, and the signal sensor 3 are arranged as described above. Then, the gain set during the adjustment is read from the memory, and the gain of the variable gain amplifier 32 is set (step S21), and the gain of the variable gain amplifier 31 is set (step S22).

After these settings, an inspection signal of an AC signal or a pulse wave is applied from the probe 14 to the wiring pattern 105 as an inspection target (step S23). Thereafter, the reference sensor 2 and the signal sensor 3 capacitively coupled to the circuit pattern are the same as the operation sequence shown in FIG. 5 described above, and the detection signals 11 and 12 are detected from the wiring pattern. These detection signals 11 and 12 are sent to a detection signal processing unit 20.

In the detection signal processing unit 20, after the gain is adjusted by the gain variable amplifiers 31 and 32 whose gain is adjusted, the peak hold circuit 21 is used to The time is unified, and the peaks of the detection signals 11 and 12 are input to the differential amplifier 22. The differential amplifier 22 amplifies the difference between the detection signal 11 and the detection signal 12 and outputs a detection signal 24. The detection signal (Vdiff) 24 of the analog signal is digitized by the A / D conversion section 23 and is output to the arithmetic processing section 7 as a determination signal 26. In addition, the detection signal Vsig output from the peak hold circuit 21 differs from the signal input to the differential amplifier 22, is directly digitized by the A / D conversion section 23, and is output to the arithmetic processing section as a determination signal 27. 7. This determination signal 27 is arranged side by side in the inspection of a substrate on which an independent network that is not divided is formed. Even if the reference sensor 2 is not used, only the signal sensor 3 can be used for inspection. In the actual product inspection, the judgment signal 26 and the judgment signal 27 can be switched and used according to the wiring pattern of the inspection.

Next, in the arithmetic processing unit 7, the determination signal 26 output from the detection signal processing unit 20 is divided by the reference value to obtain a change rate (step S24). Then, for the wiring pattern to be inspected, the change rate is compared with a threshold value (change rate> threshold value) (step S25). Based on this determination, if the rate of change is less than or equal to the threshold value (No), the wiring pattern is determined to be a good product (step S26). On the other hand, if the detection signal 24 is not 0V and the change rate is greater than the threshold value (Yes), it is determined that defective products such as disconnection are included (step S27).

This detection and determination is sequentially performed for each network, and is repeatedly performed until the inspection of all the networks is completed (step S28), and the inspection is terminated after the judgment of all the networks is completed.

According to this embodiment, a configuration can be adopted in which the gain setting is set in the differential amplifier 22 and the sensitivity can be adjusted. By using a detection circuit with a peak hold circuit, the time (phase) component of the signal can be removed. Increased on the input side of the differential amplifier 22 The benefit adjustment section is the same as the previous detection signal, so it can be used to determine the disconnection or short circuit using conventional methods.

In addition, according to this embodiment, even for a branch network having a branched portion where a wiring pattern is branched into a plurality of branched portions, a disconnection check can be performed on each branched wiring pattern.

In addition, the first and second embodiments have the following effects.

The two sensors of the reference sensor and the signal sensor are arranged above the wiring pattern after the object to be inspected is divided, and a difference amplifier is used to detect the difference between the outputs of the sensors. If the wiring of the inspected object is normal, it will not output from the differential amplifier because there is no output difference between the sensors. If there is a disconnection in the wiring of the inspected object, the output difference between the sensors will increase, so Will output from the differential amplifier.

In order to amplify and adjust the output of the sensor, by setting an amplifier at the back of the sensor to increase the gain of the differential amplifier, even if the output difference between the sensors is small, defective detection can still be performed. In addition, because of the use of a differential amplifier, it can use its in-phase removal function to eliminate noise that is superimposed on the detection signal of the sensor, and because it can simultaneously obtain the output of the two sensors, it has anti-noise. It can reduce the measurement error caused by noise, so it can improve the measurement accuracy.

Furthermore, in the first and second embodiments described above, an example in which a reference sensor is used and a wiring pattern is arranged adjacent to a branched portion shown in FIG. 1 has been described. The reference sensor can cope with the case where there are two or more divergent parts in one wiring pattern. In addition, although the reference sensor is arranged above the branched wiring pattern, in the wiring pattern, the defective wiring pattern from the position where the probe 14 contacts to the branched areas 102a and 103a becomes the reference sense. The detection signal of detector 2 is 0 (V) output, so Perform bad detection.

According to the present invention, it is possible to provide a non-contact type substrate inspection device and an inspection method thereof. For a wiring pattern having a divergent portion as an inspection object, in addition to a signal sensor configured to detect a detection signal by capacitive coupling, it is also provided. At least one reference sensor is capacitively coupled to the branched positions, and the respective detection signals are compared to perform a bad determination.

Claims (5)

A non-contact type substrate inspection device includes a power supply unit that selectively supplies an AC or pulse wave inspection signal to a plurality of wiring patterns formed on a substrate and having at least one or more divergent portions in the middle; At least one rod-shaped reference sensor, which is hung on a plurality of the above-mentioned wiring patterns, is fixed above the vicinity of the divergence and is fixed in the transverse direction, and is capacitively coupled in a non-contact manner; the same specifications as the above-mentioned reference sensor A signal sensor, which is hung on a plurality of the above wiring patterns, and after the division, is adjacent to the vicinity of the ends of the above wiring patterns and is fixed in a transverse direction, and is capacitively coupled in a non-contact manner; a detection signal processing unit It keeps the respective peak values of the first detection signal detected by the reference sensor from the wiring pattern supplied with the inspection signal and the second detection signal detected by the signal sensor from the wiring pattern, and is uniformly determined. At the same time, the difference between the first detection signal and the second detection signal is obtained, and the difference is amplified and input as a determination signal. And a defect determination unit that obtains a change rate by dividing the determination signal by a predetermined reference value, compares the change rate with a preset threshold, and performs a failure determination. The non-contact type substrate inspection apparatus according to claim 1, wherein in the defect determination section, the threshold value is a determination width having an upper limit level and a lower limit level centered on the reference value. For example, the non-contact type substrate inspection device of claim 1, wherein the reference sensor and the signal sensor have the same specifications and have the same characteristics, and are opposed to each other with the same distance between the electrodes with respect to the wiring pattern. For example, the non-contact type substrate inspection device of claim 1, wherein the detection signal processing section includes a gain adjustment section having two gain variable amplifiers, and before the defect determination, the first wiring section is replaced with a normal wiring pattern. The detection signal and the above-mentioned second detection signal are respectively amplified and adjusted so as to have the same peak value; a peak hold circuit that holds the respective peak values of the above-mentioned first detection signal and the above-mentioned second detection signal; a differential amplifier , Which performs a difference operation on each of the above peaks output from the peak holding circuit at the same time, and amplifies the calculated voltage difference; and an A / D conversion section, which converts the output of the differential amplifier into a digital signal and adds Output: Adjust the output values of the reference sensor and the signal sensor. A substrate inspection method is to use a wiring pattern including a wiring pattern formed on a substrate and having at least one branched portion on the way, separated from each other after the branching, and fixed in a direction across a plurality of wiring patterns, and all are arranged in a non-contact manner The reference sensor and the signal sensor of the same specifications that are rod-shaped and have a bad disconnection inspection by capacitive coupling, the substrate inspection method includes the following: outputting the above-mentioned reference sensor to a normal wiring pattern And the way that the output of the above-mentioned signal sensor is a detection signal with the same peak value, adjust the gain, and detect the first detection from the above-mentioned reference sensor arranged in a non-contact manner above the wiring pattern after the divergence of the divergent part. The signal is detected by the above-mentioned signal sensor which is arranged in a non-contact manner near the end of the wiring pattern after the branching, and detects the second detection signal, and maintains the respective peak values of the first detection signal and the second detection signal. , Output the peaks at the same time, perform a difference operation on each of the peaks, and amplify the calculated voltage difference to generate The determination signal is obtained by dividing the determination signal by a predetermined reference value to obtain a change rate, and setting the threshold value of the change rate to a predetermined threshold having a upper limit level and a lower limit level centered on the reference value. The comparison is performed to make a bad judgment.