JP4644745B2 - Circuit pattern inspection device - Google Patents

Description

  The present invention relates to a circuit pattern inspection apparatus capable of inspecting a defect of a conductive pattern formed on a substrate in a non-contact manner.

  In recent years, a liquid crystal display device using a liquid crystal on a glass substrate or a plasma display device using plasma has become mainstream as a display device. In the manufacturing process of these display devices, a defect inspection for the presence or absence of disconnection and short circuit is performed on the conductive pattern to be the circuit wiring formed on the glass substrate.

  As a conventional method for inspecting a conductive pattern, for example, as described in Patent Document 1, a pin tip of an inspection probe is brought into contact with both ends of a conductive pattern, and a DC inspection signal is sent from one inspection probe. A contact-type inspection method (pin contact method) is known in which a DC inspection signal is applied and propagated from the other inspection probe, and the presence or absence of a detection signal is inspected for disconnection or short circuit.

  As another inspection method, Patent Document 2 discloses that an AC inspection signal is transmitted from one inspection probe while moving at least two inspection probes close to the conductor pattern and capacitively coupling with the conductor pattern. The AC inspection signal that has been applied and propagated through the conductor pattern is detected by the other inspection probe. The presence or absence of disconnection and short circuit in the conductive pattern is inspected by the change in the waveform of the detection signal.

JP-A-62-269075 JP 2004-191381 A

  The above-described display device is required to have a large display screen, the screen size is further increased, and the display screen is required to be fine so that display pixels are miniaturized. For this reason, conductive patterns such as drive wirings and signal lines of the display pixels are lengthened and miniaturized.

  When inspecting a large number of conductive patterns, in the inspection probe that makes contact with the pin tip as proposed in Patent Document 1, as a first method, the inspection probe is arranged so as to cross over the arranged conductive patterns. Either slide and move to sequentially inspect, or as a second method, deploy the same number of inspection probes as the number of conductive patterns and contact the inspection probes in a batch, or as a third method, While moving the inspection probe up and down, the inspection probe is selectively moved to contact the conductive pattern.

  When the inspection probe is slid and moved, the pin tip moves while being in contact with the conductive pattern, so that damage due to peeling or scratching becomes a problem. Even when the inspection probe is brought into contact with the conductive pattern without sliding, damage such as scratches due to pressing of the conductive pattern due to contact of the pin tip becomes a problem. Further, when trying to automate the contact operation and movement of the inspection probe using a program or the like, the position control becomes not easy as the conductive pattern becomes thinner and the wiring interval becomes smaller.

  Further, in an inspection apparatus using an electrode capacitively coupled to a conductor pattern in a non-contact manner, the value of the detected inspection signal decreases as the surface area of the conductive pattern facing the electrode decreases. If the value of the inspection signal applied to the conductive pattern is increased, the detected inspection signal is also increased. However, as the conductive pattern is miniaturized, the allowable inspection signal value is also decreasing. Further, the detection signal is detected by including noise superimposed from the outside in addition to the inspection signal. For this reason, skill level is required to determine whether or not the inspection signal is noise, and it is difficult to set a reference value when performing computer determination.

  In addition, when the moved inspection is performed on the inspection target substrate using one sensor unit, one detection signal is obtained. When the determination is performed with only one detection signal, it is possible to determine the presence or absence of a defect from a slight signal change by setting a strict threshold, but at the same time for noise components that may be included in the detection signal Therefore, it cannot be determined whether or not the obtained determination result is only a true defect. Therefore, the second inspection is performed again under the same conditions, and the obtained second inspection result is compared with the first inspection result to determine the defect. Therefore, in order to obtain an accurate inspection result, it is necessary to perform at least two inspections on the same inspection object under the same inspection conditions. In this inspection method, it takes time to perform two inspections in order to obtain an accurate inspection result. Therefore, it is not easy to shorten the inspection time. In addition, if there is time between the first inspection and the second inspection, it is not easy to inspect under the same inspection conditions.

In order to achieve the above object, an embodiment according to the present invention targets a substrate on which a plurality of conductive patterns are formed in a row, and is opposed to the first conductive pattern of the conductive patterns. Both the first sensor pair including the first power supply electrode and the first sensor electrode, and the second conductive pattern separated by a predetermined number of patterns from the first conductive pattern, A second sensor pair having a second feeding electrode and a second sensor electrode facing each other, and holding the first sensor pair and the second sensor pair, and spaced apart by a certain distance above the conductive pattern Then, a moving part that moves the rows of the conductive patterns so as to cross each other, and the movement of the first sensor pair and the second sensor pair by the moving part, the first feeding electrode and the second 2 from the AC signal to the feed electrode An inspection signal supply unit that supplies the same inspection signal and sequentially applies the inspection signal to each conductive pattern in which the first power supply electrode and the second power supply electrode face each other and are capacitively coupled. A first detection signal and a second detection signal acquired in advance by the first sensor electrode and the second sensor electrode, which are capacitively coupled to the conductive pattern to which the signal is applied, respectively, are determined in advance. By comparing the determination reference values, defect candidates are selected, and the position of one of the detection signals is set so that the positions of the conductive patterns on the first detection signal and the second detection signal match. wherein the test signal processor and said first detection signal whose position is consistent of the conductive pattern and the second detection signal having a distance off-axis matching unit for performing distance axis matching that moved defect Comparing the complement each other, to provide a circuit pattern inspection anda determining the defect determination unit and true defect common to the conductive pattern defect candidate exists in the same pattern position.

  In order to achieve the above object, an embodiment according to the present invention targets a substrate on which a plurality of conductive patterns are formed in a row, and is opposed to the first conductive pattern of the conductive patterns. Both the first sensor pair including the first power supply electrode and the first sensor electrode, and the second conductive pattern separated by a predetermined number of patterns from the first conductive pattern, A second sensor pair having a second feeding electrode and a second sensor electrode facing each other, and holding the first sensor pair and the second sensor pair, and spaced apart by a certain distance above the conductive pattern Then, a moving part that moves the rows of the conductive patterns so as to cross each other, and the movement of the first sensor pair and the second sensor pair by the moving part, the first feeding electrode and the second 2 from the AC signal to the feed electrode An inspection signal supply unit that supplies the same inspection signal and sequentially applies the inspection signal to each conductive pattern in which the first power supply electrode and the second power supply electrode face each other and are capacitively coupled. The first detection signal and the second detection signal obtained by the first sensor electrode and the second sensor electrode are capacitively coupled to the conductive pattern to which the signal is applied, respectively. A defect candidate is selected by comparison with the determination reference value, and the position of one of the detection signals is moved so that the positions of the conductive patterns on the first detection signal and the second detection signal coincide with each other. An inspection signal processing unit that performs distance axis matching, and the defect candidates in the first detection signal and the second detection signal in which the positions of the conductive patterns are matched are compared, and the same pattern To provide a circuit pattern inspection apparatus having a true defect and determine the defect determination unit, a common said conductive pattern candidate defects that exist in the location.

  Further, a substrate on which a plurality of conductive patterns are formed in a row is to be inspected, and a predetermined number of patterns are arranged in parallel in a direction intersecting the row of the conductive patterns for detecting a conductive pattern having a defect. An inspection method for a circuit pattern inspection apparatus comprising an inspection unit composed of a pair of at least two sets of feeding electrodes and sensor electrodes, wherein the inspection unit is moved in a direction crossing the column, The same inspection signal composed of an AC signal from the feeding electrode is sequentially applied to different conductive patterns separated by capacitive coupling, and the inspection signals propagated through the respective conductive patterns to which the inspection signal is applied are respectively coupled by capacitive coupling. A first detection signal and a second detection signal are obtained from the sensor electrode, and a predetermined determination is made with respect to the first detection signal and the second detection signal. A defect candidate is selected by comparing the quasi-values, and the position of one of the detection signals is moved so that the positions of the conductive patterns on the first detection signal and the second detection signal coincide with each other. Axis matching is performed, and the defect candidates in the first detection signal and the second detection signal in which the positions of the conductive patterns are matched are compared with each other. Provided is an inspection method for a circuit pattern inspection apparatus for determining a true defect of a pattern.

  According to the present invention, each of the conductive patterns arranged on the substrate is detected a plurality of times using a plurality of sets of sensors in time series, and a determination signal obtained by multiplying those detection signals is generated. It is possible to provide a circuit pattern inspection apparatus that realizes appropriate determination of pattern quality.

FIG. 1 is a diagram showing a conceptual configuration of a dual inspection unit of a circuit pattern inspection apparatus according to the present invention. 2A and 2B are diagrams for explaining determination of the presence or absence of defects in the circuit pattern inspection apparatus. FIG. 3 is a block diagram showing the overall configuration of the circuit pattern inspection apparatus according to the present embodiment. FIG. 4 is a diagram showing a conceptual configuration of a dual inspection unit of the circuit pattern inspection apparatus. FIG. 5A is a diagram illustrating a detection signal by the dual channel electrode in the inspection signal processing unit, and FIG. 5B is a diagram illustrating a signal obtained by smoothing the detection signal. (c) is a figure which shows the detection signal which performed the distance axis matching process. FIG. 6A is a diagram illustrating a difference signal obtained by calculating a difference between detection signals subjected to the distance axis matching process, and FIG. 6B is a process of performing minute change emphasis processing by product operation on the difference signal. FIG. 6C is a diagram showing a signal obtained by smoothing spike noise in the product signal. FIG. 7 is a diagram for explaining measurement in the circuit pattern inspection apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The circuit pattern inspection apparatus according to the present invention is, for example, a substrate for detecting a defective pattern of disconnection or short circuit of a plurality of conductive patterns (wiring patterns) formed on a glass substrate in a manufacturing process. This is a separate inspection device. The conductive pattern to be inspected is, for example, a circuit wiring used for a liquid crystal display panel, a touch panel, and the like. It is a comb-like conductive pattern connected. Each conductive pattern formed on the substrate can be inspected even if it is not arranged at equal intervals as long as the position of the pattern can be determined. Furthermore, when the dual inspection section described later moves, if the power supply electrode and the sensor electrode can be opposed to each other on the same conductive pattern, the same inspection can be performed even if there is a bend or width change in the middle of the conductive pattern It is. In the following description, in order to facilitate understanding, a conductive pattern formed in a linear row at regular intervals will be described as an inspection target.

  FIG. 1 is a diagram showing a conceptual configuration of a dual inspection unit of a circuit pattern inspection apparatus according to the present invention. 2A and 2B are diagrams for explaining determination of the presence or absence of defects in the circuit pattern inspection apparatus.

  As shown in FIG. 1, a circuit pattern inspection apparatus 1 includes a dual inspection unit 2 provided at a predetermined distance above a plurality of rows of conductor patterns 101 formed on an insulating substrate 100 such as a glass substrate. An inspection signal supply unit 13 that supplies an inspection signal consisting of alternating current to the dual inspection unit 2, an inspection signal processing unit 5 that performs signal processing described later on the detection signal detected from the dual inspection unit 2, and a control unit described later A defect determination unit 20 provided in (the control unit 6 shown in FIG. 2) and a display unit 8 for displaying inspection information including inspection results are provided.

  The dual inspection unit 2 has two sets of inspection units each composed of a pair of power supply electrode and sensor electrode. Specifically, the dual inspection unit 2 is supplied to the inspection pattern supply unit 11 including the feeding electrodes 21 (21 a and 21 b) for supplying (applying) the inspection signal to the conductive pattern 101 and the conductive pattern 101. The sensor unit 12 includes sensor electrodes 22 and 23 that detect an inspection signal as a detection signal S0. In this example, both the first inspection part consisting of the feeding electrode 21a and the sensor electrode 22 located above the same conductor pattern, and the conductive pattern that is several distances away from the first inspection part. The power supply electrode 21b is positioned, and the second inspection unit including the sensor electrode 23 is included. The power supply electrode 21b and the sensor electrode 23 are also located above the same conductor pattern.

  The inspection signal supply unit 13 applies AC inspection signals having the same voltage value and the same frequency to the feeding electrode 21a and the feeding electrode 21b, respectively, at the same cycle timing. The power feeding electrodes 21a and 21b are capacitively coupled to the conductive patterns 101 facing each other and apply an AC inspection signal. These inspection signals propagate through the conductive pattern 101 and are acquired by the sensor electrodes 22 and 23 that are capacitively coupled to face each other. The inspection signal may be a signal that is propagated by capacitive coupling, and may be not only a sinusoidal alternating current but also a rectangular (pulse) wave signal.

  In these units 11 and 12, the moving mechanism 3 applies the inspection signal to the conductive pattern 101 from the power feeding electrodes 21a and 21b, and the sensor electrodes 22 and 23 detect the inspection signal from the conductive pattern 101. In the state where the same distance (measurement gap) is maintained above the pattern, it is moved so as to cross (cross) the row of the conductive pattern. Note that the inspection signal supply unit 11 and the sensor unit 12 are arranged apart from each other on the substrate to be inspected (for example, both ends of the conductive pattern) as long as the conductive pattern, the feeding electrode, and the sensor electrode face each other. Or, conversely, they may be arranged at close positions. This is because the dual inspection unit 2 detects a change in the detection signal by capacitive coupling, and thus the capacitance in the conductive pattern appears as a change in the detection signal due to disconnection, unlike the normal state.

  The first inspection unit and the second inspection unit configured as described above perform an inspection operation integrally over the substrate 100 to be inspected in a single scanning movement to form one conductive pattern 101. On the other hand, both are inspected once, and the detection signals S0a and S0b detected for each include the inspection results for the same conductive pattern. That is, when viewed from the inspection unit side, a result for two times can be obtained by one inspection, and when viewed from the conductive pattern side, the inspection is performed twice with a slight time difference.

  FIG. 2A shows a determination signal Sja from the first inspection unit (sensor electrode 22) and a determination signal Sjb from the second inspection unit (sensor electrode 23). It is a figure for demonstrating selection of a candidate. Here, the vertical axis can be a signal value, and the horizontal axis can be a time axis or a conductive pattern position.

  When the inspection signal supply unit 11 moves above the conductive pattern, the same AC alternating inspection signal is applied from the power supply electrode 21a and the power supply electrode 21b to different conductive patterns by capacitive coupling.

  The sensor electrodes 22 and 23 detect the inspection signals transmitted through the conductive pattern 101 while passing above the pattern as the detection signal S0a from the sensor electrode 22 and the detection signal S0b from the sensor electrode 23, respectively. Therefore, two inspection results can be obtained for one conductive pattern 101. Since the inspection results of these two inspection results are shifted by the distance between the sensors, the inspection positions are aligned by distance axis matching described later. Here, the distance axis matching means that the sensor electrode 22 and the sensor electrode 23 are arranged at a distance of several patterns, so that the two detection data (detection signals) are equivalent to the distance. Deviation has occurred. In order to compare these, one or both of the detection data are brought close to each other so as to eliminate the difference corresponding to the distance, and moved so that the same conductive pattern matches on the axis.

In FIG. 2B, the respective determination signals shown in FIG. 2A are moved in the horizontal axis direction so that the pattern positions on the vertical axis coincide with each other.
First, the detection signals S0a and S0b are sent to the inspection signal processing unit 5. The inspection signal processing unit 5 amplifies the detection signal and removes a noise component from the amplified detection signal as necessary, and generates determination signals Sja and Sjb from the inspection signals S0a and S0b. 20 is sent out.

  First, as shown in FIG. 2A, the defect determination unit 20 compares the same reference signal as a predetermined determination reference with each of the determination signals Sja and Sjb to obtain a peak value below the reference. On the other hand, defect candidates Pa1, Pa2 and Pb1, Pb2 are selected. In FIG. 2A, the peak signal below the reference (or below the reference) is set as the defect candidate, but in the signal detection method, the peak signal above the reference (or above the reference) is set. May be set as a defect candidate.

  As described above, the determination signals Sja and Sjb are arranged in the determination signal as shown in FIG. 2B because the sensor electrode 22 and the sensor electrode 23 are arranged at a distance of several patterns. The pattern positions are matched by distance axis matching so that the patterns are at the same position (same detection timing).

  Next, the defect candidates Pa1, Pa2 and Pb1, Pb2 in the determination signals Sja, Sjb shown in FIG. In this comparison, defect candidates Pa2 and Pb1 coincide on the vertical axis. For the other defect candidates Pa1 and Pb2, there is no defect candidate that coincides on the vertical axis. Based on this comparison result, the defect determination unit 20 determines the defect candidates Pa2 and Pb1 as true defects, and determines that the other defect candidates Pa1 and Pb2 are pseudo defect candidates, that is, noise or the like. That is, the defect in the conductive pattern is invariant, and even if the inspection is performed a plurality of times, a detection signal indicating the same defect can be obtained. On the other hand, noise or the like superimposed on the detection signal often occurs in a short time and in a single shot. Therefore, when the defect candidate included in the detection signal by the first first inspection unit is not included as a defect candidate in the detection signal by the second inspection unit after that, the defect candidate of the first inspection unit is It is determined that the defect is a pseudo defect caused by noise or the like.

  In the present embodiment, the inspection unit is configured by two pairs of power supply electrodes and sensor electrodes, but of course, it is not limited to two sets. If necessary, three or more power supply electrodes and sensor electrodes are used. A pair of may be used.

  From the above, according to the dual inspection unit of the present embodiment, when viewed from the inspection unit side, the first inspection unit and the second inspection unit are inspected by moving the inspection substrate 100 above once. Are inspected, and one conductive pattern 101 is inspected once, and detection signals S0a and S0b are obtained respectively. Both of these detection signals include the inspection result for the same conductive pattern, and two results can be obtained by one inspection. A defect candidate is selected from these detection signals, and the defect candidate existing at the same position is determined as a true defect in the detection signal obtained by performing pattern alignment.

Therefore, an accurate determination can be realized by the inspection signal obtained by one detection operation, and a quality result of the conductive pattern from which noise and the like are appropriately removed can be obtained.

Next, a circuit pattern inspection apparatus according to the second embodiment of the present invention will be described.
FIG. 3 is a block diagram showing the overall configuration of the circuit pattern inspection apparatus according to the second embodiment. FIG. 4 is a diagram illustrating a configuration of a dual inspection unit in the circuit pattern inspection apparatus. In addition, the same reference numerals are given to the parts equivalent to the constituent parts shown in FIG.

  The circuit pattern inspection apparatus 1 includes a dual inspection unit 2 that is set so as to be spaced a predetermined distance above the plurality of rows of conductor patterns 101 formed on the substrate 100 described above, and the dual inspection unit 2. A moving mechanism 3 that maintains a separated (non-contact) state and moves so as to cross over the conductor pattern 101, a drive control unit 4 that drives and controls the moving mechanism 3, and an inspection signal that is an AC signal to the dual inspection unit 2 Noise to generate a detection signal S0 (S0a, S0b) obtained by subtracting the noise signal from the noise electrodes 22b, 23b from the detection signal detected from the sensor electrodes 22a, 23a of the dual inspection unit 2 The removal units 24 and 25, the inspection signal processing unit 5 for performing signal processing to be described later on the detection signal S0 (S0a, S0b), the entire apparatus and the inspection signal processing. A control unit 6 that performs good / bad defect determination of the conductive pattern based on a defect determination signal Sj from the processing unit 5 and an input unit 7 that includes a keyboard, a switch panel, and the like for instructing the control unit 6 are input. And a display unit 8 for displaying inspection information including inspection instructions and inspection results.

  The dual inspection unit 2 includes an inspection signal supply unit 11 that supplies (applies) an inspection signal to the conductive pattern 101 and a sensor unit 12 that detects the inspection signal supplied to the conductive pattern 101. These units are moved by the moving mechanism 3 while maintaining the same separation distance (measurement gap) upward with respect to the conductive pattern 101. Although not shown, the moving mechanism 3 is provided with a distance sensor for measuring the distance from the conductive pattern 101 and a height adjusting mechanism, and conducts the inspection signal supply unit 11 and the sensor unit 12 during the inspection. The distance from the pattern is adjusted so as to be always constant.

  As shown in FIG. 3, the inspection signal supply unit 11 is provided with power supply electrodes 21 a and 21 b that are separated from each other by the same distance above the conductive pattern 101 that is separated by several patterns. An AC test signal having the same voltage value and the same frequency is applied from the test signal supply unit 13 to the power supply electrodes 21a and 21b at the same cycle timing. The electrode widths of the power supply electrodes 21a and 21b are set as appropriate, and may be equal to or smaller than the width of the conductive pattern 101 as long as the inspection signal can be properly supplied. If no signal is applied, the conductive pattern 101 may have a width or larger.

  In the present embodiment, the sensor unit 12 is provided with sensor pairs 22 and 23 each having a pair of two sensor electrodes.

  For example, in the sensor pair 22, one sensor electrode 22a is disposed so as to face the same conductive pattern as that of the power supply electrode 21a. The paired sensor electrodes 22b are arranged so as to face above the conductive pattern 101 that is several patterns away from the sensor electrode 22a. The sensor electrode 22b is arranged above the conductive pattern several patterns away from the conductive pattern to which the inspection signal is supplied, and is configured to detect noise. In the following description, the sensor electrode 22b is referred to as a noise electrode 22b.

  As in the present embodiment, in the case where measurement is performed using capacitive coupling by an inspection electrode that is not in contact with an inspection target (conductive pattern), an absolute reference potential (eg, GND: 0 V) as in a contact sensor. Does not exist. Accordingly, the noise electrode 22b having the same characteristics as the sensor electrode 22a is provided, and detection is performed on the conductive pattern to which no inspection signal is supplied, and a signal value in a no-signal state, for example, a noise signal is detected. An appropriate detection signal is obtained by comparing or subtracting the superimposed noise from the inspection signal detected by the sensor electrode 22a.

  The actual detection signal detected by the sensor unit 12 includes not only periodic noise caused by the wiring pitch in the conductor pattern, but also mechanical servo noise generated during movement, fluctuations in the separation distance, and devices arranged in the periphery The effects of common mode noise (noise propagating on the ground line) are also included.

  In the present embodiment, the noise electrode 22b is disposed at a position away from the sensor electrode 22a by a predetermined distance, for example, 2 mm. With this configuration, a detection output by the sensor electrode 22a and a detection output by the noise electrode 22b are sent to the inspection signal processing unit 5, and a virtual ground potential (GND) is created by subtracting the superimposed noise, and noise is also generated. Removal is in progress.

  In the present embodiment, FIG. 1 shows an example in which the inspection signal supply unit 11 and the sensor unit 12 are arranged at both ends of the conductive pattern 101. However, this arrangement is only shown as an example, May be provided close to each other. Also, the inspection location does not need to be on both ends of the conductive pattern 101. When the inspection signal supply unit 11 and the sensor unit 12 are arranged close to each other on the base plate as a single unit, they intersect at the center side or at either end as long as it is above the conductive pattern. If it is moved like this, the inspection can be carried out.

  In the present embodiment, the sensor electrodes 22a and 23a and the noise electrodes 22b and 23b have a width that is equal to or larger than the width of the conductive pattern 101 and that does not affect the adjacent conductive pattern in order to detect a signal value as large as possible. That is, it has a width equal to or less than the sum of the width of the conductive pattern 101 and the space between adjacent patterns (two spaces on both sides). Further, the direction along the conductive pattern is not limited, and the length of the electrode may be set as appropriate.

Next, the inspection signal processing unit 5 will be described.
The inspection signal processing unit 5 includes electronic circuits including a smoothing unit 14, a distance axis matching unit 15, a difference value calculating unit 16, a minute change emphasizing unit 17, and a spike noise smoothing unit 18. . Further, a defect determination unit 20 in the control unit 6 that performs defect determination on the conductive pattern 101 is used.

  The inspection signal processing unit 5 performs smoothing processing on the input inspection signals S0a and S0b, the above-described distance axis matching processing, difference value calculation processing, minute change enhancement processing, and spike noise. Smoothing processing is sequentially performed. The inspection signal is subjected to these processes, converted into a defect determination signal Sj (Sja, Sjb), and sent to the defect determination unit 20 that performs defect determination for all the conductive patterns 101. The defect determination unit 20 determines the presence or absence of a defect based on the determination signals Sja and Sjb, and displays the determination result on the screen of the display unit 8.

  The control unit 6 includes a CPU (central processing unit) 19 that controls each component of the entire apparatus, a defect determination unit 20, and a memory 9 that stores information about programs and data.

The memory 9 is a general memory, and stores, for example, a control program, various calculation programs, data (table), and the like using a ROM, a RAM, a flash memory, or the like.

Next, with reference to FIGS. 5A to 5C and FIGS. 6A to 6C, processing by each component of the inspection signal processing unit 5 will be described. FIG. 7 shows the measurement conditions.
FIG. 5A shows the detection signals S0 (S0a, S0b) of the sensor pairs 22 and 23, respectively. This detection signal S0 is obtained by taking the difference between the detection signals (noise signals) detected by the noise electrodes 22b and 23b from the detection signals detected by the sensor electrodes 22a and 23b, and removing the noise and generating a virtual ground potential (GND). It is.

  In the present embodiment, as described above, since the sensor pairs 22 and 23 are arranged at intervals of a plurality of conductive patterns, the sensor pairs 22 and 23 are moved above the conductive pattern 101 on the substrate 100 as shown in FIG. Thus, when inspections are performed in time series, a time difference occurs when passing over the same conductive pattern. For this reason, in the detected signals S0a and S0b, the same change occurs in the signal waveform with a time difference as shown by A1, A2 and A3 in FIG.

  In addition, when an inspection signal is applied to the conductive pattern, noise may enter separately from the outside, and the noise may be detected by being superimposed on the detection signal. Most of these noises are added instantaneously, and when two sensor electrodes are shifted in time and detected for the same conductive pattern, even if noise is detected with one sensor electrode, The noise is not detected in the other sensor electrode. Therefore, by providing this time difference, if the detection signals of the two electrodes are compared, it can be determined whether the detection signal is a change or noise.

  Next, if necessary, the detection signal is smoothed to slow down the amplitude and fluctuation of the detection signal. Here, fluctuation means that the value (voltage value) changes so that the entire signal (or the center of amplitude) undulates as shown in FIG. FIG. 5B shows the detection signal S1 (S1a, S1b) obtained by performing the smoothing process on the detection signal by the smoothing unit 14. Smoothing processing is performed using a general smoothing circuit to dull the amplitude of the detection signal.

  Since the smoothed detection signals S1a and S1b still have a time difference (phase difference), as shown in FIG. 5C, the distance axis matching unit 15 matches the phases of the two detection signals. A matching process is performed. By this matching processing, the detection signal S2 (S2a, S2b) is indicated by A1 shown in FIG. In this matching process, since the distance between the two sensor electrodes and the moving speed of the sensor electrode at the time of detection are known, the moving distance difference can be easily calculated. It is only necessary to move one detection signal by the movement distance difference.

  By this matching process, detection signals in the same conductive pattern are matched. This indicates that, for example, A1 that surrounds the same point of interest shown in FIG. 5A is inclined, but by executing the matching process, A1 becomes vertical and the inclination disappears and matches. ing.

  Further, the difference value calculation unit 16 calculates a difference between the coincident detection signals S2a and S2b. Specifically, the difference signal S3 (S3a, S3b) shown in FIG. 6A is the difference from the previous signal value when the detection signals S2a, S2b are signal values sampled at a certain interval. Is a signal plotted with the value of this difference. For this reason, the output voltage value on the vertical axis is two digits or more smaller than that in FIG. Further, by taking the difference between the signals, only the characteristics of the change of the two difference signals S3a and S3b can be extracted, and a coincident virtual ground potential (GND) can be created. Due to the virtual ground potential, fluctuation of the entire signal (up and down change of the reference value of the signal amplitude) is eliminated, and the signal has an amplitude at a constant reference value (0 V).

  FIG. 6B shows a product signal S4 obtained by performing enhancement processing on the difference signals S3a and S3b by the minute change emphasizing unit 17. In this enhancement process, an arithmetic process (hereinafter referred to as a product operation) based on the product of the difference signal S3a and the difference signal S3b is performed. In this product operation, if there is a defective portion in the same conductive pattern 101, both the difference signals S3a and S3b have a change in the signal value. The change is more emphasized than the value. Briefly, for example, if the signal value at normal time is 3 and the signal value at failure (with defects) is 5, the pass / fail judgment must be made based on the difference of 2.

However, if the signals detected twice from the same conductive pattern are multiplied as in this embodiment, 3 × 3 = 9 at normal time and 5 × 5 = 25 at failure, and 9 and 25 are compared. Based on the difference 16, it is possible to make a pass / fail judgment.
According to the measurement result using the measurement conditions according to FIG. 7 in the present embodiment, the detection signals at points A1, A2, and A3 shown in FIG. 6B are emphasized.

  Next, as shown in FIG. 6C, the spiked noise smoothing unit 18 using a general filter or the like is subjected to the spike noise smoothing process on the enhanced product signal S4. By this processing, the signal is slowed down against a steep change in a very short time to make the spike noise inconspicuous, thereby reducing the amplitude change signal as shown in FIG. 6C (defect determination signal Sj). ) Can be obtained.

  Next, the determination signal Sj is sent to the defect determination unit 20 provided in the control unit 6. In the defect determination unit 20, a determination threshold value as shown in FIG. 6C is set. This determination threshold is appropriately set based on the normal value of the determination signal Sj (range of the signals B1 and B2). In the present embodiment, as an example, the determination threshold is set to 0.00012 V, which is approximately twice the peak value at normal time. With respect to the conductive pattern 101 in which the signal values A1, A2, and A3 exceeding the determination threshold are detected, it is determined that the three conductive patterns 101 have a defect (disconnection). In addition, the conductive pattern 101 having a defect can be specified based on the moving distance shown on the horizontal axis of the graph.

  As described above, in the circuit pattern inspection apparatus according to the present embodiment, when the moved feeding electrode 21a faces the conductive pattern to be inspected, it is capacitively coupled in a non-contact manner and an AC inspection signal is generated. The first detection signal is detected from the sensor electrode 22a facing the conductive pattern. Further, when the power feeding electrode 21b to be moved is opposed to the same conductive pattern after a lapse of time, an AC inspection signal is applied in a non-contact capacitive manner, and at that time, from the sensor electrode 23a facing the conductive pattern. A second detection signal is detected.

Therefore, in the present embodiment, the same conductive pattern is detected twice by at least two pairs of sensors, and the presence or absence of a defect is determined by comparison with two synchronized detection signals.
Further, in the determination based on this comparison, if there is little change in the two detected signals, the product of the first detection signal and the second detection signal is taken to significantly change the signal at the defective portion. An enhanced defect determination signal is generated. In the defect determination signal, noise that is constantly superimposed on the detection signal is removed using the detection signal of the noise electrode.

  In the present embodiment, an example in which each conductive pattern is detected twice by two sensor pairs has been described, but of course, the present invention is not limited, and two or more sensor pairs are used. Two or more detections may be performed.

  In the above-described embodiment, the sensor electrode and the noise electrode are a pair of sensors. However, when the sensor electrode (first sensor electrode) faces a certain conductive pattern, it faces the adjacent conductive pattern. By providing the second sensor electrode adjacent to each other, it is possible to detect not only a disconnection defect but also a short-circuit defect. In this case, the second sensor electrode does not necessarily face the adjacent conductive pattern, and it is possible to detect the second sensor electrode only by being applied to a part of the conductive pattern. In the above-described example, the enhancement processing is performed by taking the product of two detection signals, but product calculation may be performed on two or more detection signals.

  Further, in the present embodiment, in order to improve the inspection time efficiency (inspection processing speed improvement), the dual inspection unit 2 is mounted and the moving mechanism 3 continuously inspects the moving state. . On the other hand, the inspection method of the present invention is also applied to an inspection apparatus in which an existing circuit pattern inspection apparatus mounts, for example, one sensor pair (sensor electrode and noise electrode) or one sensor (sensor electrode only). Is possible. That is, by performing step movement for stopping movement for each arranged conductive pattern and performing inspection at least twice at the time of stopping, an inspection result having a time difference can be obtained. By performing the above-described inspection signal product operation on these inspection results, a similar defect determination signal as shown in FIG. 6C can be obtained, and an equivalent inspection result can be obtained. .

  That is, as long as a plurality of detection signals having a time difference can be acquired for one inspection target, the present invention can be applied to any inspection apparatus, and an equivalent inspection result can be obtained. Although it is not possible in practice, as a mere theory, if the detection signal clearly has no noise superimposed on it, even if it is a product of one detection signal S (S × S), an equivalent inspection result is obtained. Obtainable. The product operation may be performed a plurality of times.

  In addition to this embodiment, even if the detection signal is multiplied by a certain coefficient, the difference between the detection signal of the normal conductive pattern and the detection signal of the conductive pattern having a defect can be increased to some extent. Since the detection coefficient of each conductive pattern is multiplied by the same coefficient, if the difference between the detection signals is small, the difference does not become so large, and it cannot be said that the determination is always easy, and the coefficient It is not adopted because it has no basis and deviates from the gist of the invention.

Next, a circuit pattern inspection apparatus equipped with a dual inspection unit according to the second embodiment shown in FIG. 7 will be described.
In this embodiment, the inspection signal processing unit 5 in the first embodiment is implemented using an electronic circuit. However, in this embodiment, the signal processing executed by the inspection signal processing unit 5 is performed by application software (high precision This is an example realized by a defect extraction algorithm).

In this embodiment, first, the detection signals obtained by the sensor pairs 22 and 23 are subjected to a smoothing process for slowing the amplitude and fluctuation of each detection signal [smoothing process step].
Next, when the detection signal obtained by the sensor pair 22 is fn, the detection signal obtained by the sensor pair 23 is gn, and ½ of the number of data points forming the waveform including the defect is i, The difference in the number of data of i

[Difference value calculation processing step].

Here, it is assumed that both detection signals include a distance offset (distance corresponding to several sequences of conductive patterns), and the number of conductive patterns therebetween is j. At this time, it is moved by j pieces corresponding to the number of conductive patterns, and matching is performed at the same timing [distance axis matching processing step]. That is, the distance axes of both detection signals are matched.
Next, the product of the detection signals f′n and g′n subjected to such difference and matching processing (Equation 1)

As described above, only a steep change indicating a defective portion is emphasized [small change emphasis].

Furthermore, hn is the sum of time series with 2i of the number of defect shape data.

Is calculated and the spike noise component is smoothed [spike noise smoothing step]. As a result of the processing as described above, finally, as shown in FIG. 6C, a defect determination signal including the conductive pattern signals A1, A2, and A3 having defects is generated.

  In the present embodiment, the obtained defect determination signal has a minimum level of 0.0001748 in the conductive pattern having a defect with respect to the measurement standard deviation 6σ = 0.00008254 in the normal conductive pattern. In other words, the minimum standard deviation in a normal conductive pattern having no defect is 6 times (6σ), and the difference in change of the defect portion is actually 1.96 times.

  Therefore, it is easy to provide an appropriate threshold value for performing defect determination. A defective conductive pattern in which a disconnection or the like has occurred can be easily detected. As a result of repeating such measurement about 30 times as the number of evaluations, the same measurement result was obtained and the stability was also confirmed.

  As described above, according to the circuit pattern inspection apparatus equipped with the dual inspection unit, the inspection signal processing unit is generated by generating the defect determination signal by the defect extraction processing for the detection signal using software (defect extraction algorithm). Even if it is not constituted by circuit elements, it is possible to obtain the same operational effects as those of the first embodiment described above. In this embodiment as well, the defect determination signal is generated by a product operation using two detection signals. However, even if there are two or more detection signals, it can be easily handled by rewriting the program.

  Further, in the processing of the application software described above, a known technique such as a smoothing differential method can be used for the smoothing process, and a smoothing method or a cumulative average can be used for the spike noise smoothing process. A known method such as a method can be used.

  Note that the inspection signal in each of the embodiments described above is not limited to an AC signal composed of a sine wave, and may be a pulse signal. The frequency is also arbitrary, and a suitable frequency may be set as appropriate according to the conductive pattern to be inspected.

  FIG. 7 shows an example in which nine display devices used for an image display device are arranged on a glass substrate as an inspection target.

  These display devices are in the middle of the manufacturing process and are in a state in which the conductive pattern 101 is formed on the substrate 100. The substrate 100 is placed on the inspection table 102 of the circuit pattern inspection apparatus 1 and is held by a suction mechanism (not shown) so as not to move during the inspection. In the following description, the inspection signal supply unit 11 and the sensor unit 12 are referred to as an inspection unit.

  The inspection part is provided in the arm part 103 of the moving mechanism 3, and these are provided so as to be individually slidable in the longitudinal direction of the arm part 103 of the moving mechanism 3. A linear motor or the like (not shown) is used as the sliding mechanism. Further, the moving mechanism 3 can reciprocate in the longitudinal direction of the guide member 104 by the guide members 104 arranged on both ends of the arm portion 103. FIG. 7 shows a state in which each member is in the initial position.

  In response to the inspection start instruction, the inspection unit waiting at the initial position D0 moves to the position D1 in the arm unit 103. Along with this movement, the arm portion 103 moves in the longitudinal direction of the guide member 104 toward the position D2. At this time, the inspection unit performs detection on the opposing conductive patterns. In this example, the three display devices are inspected before the inspection unit reaches the position D2.

  Next, the inspection unit moves on the arm unit 103 to the position D3. The arm part 103 moves to the position D4 in the direction different from the above. The inspection unit performs the inspection on the three display devices until the position D4 is reached. After reaching the position D4, the inspection unit moves to a position D5 in the arm unit 103. Thereafter, the arm portion 103 moves in the longitudinal direction of the guide member 104 and moves toward the position D6. During this movement, the inspection unit performs inspection on the three display devices until the position D6 is reached. When the arm portion 103 reaches the position D6, the detection operation for the conductive pattern of the display device on this substrate is completed. After completion of the inspection, the arm part 103 returns to the initial position, and the inspection part also returns to the position D0.

  In addition, in the pass / fail judgment of the conductive pattern, after acquiring the inspection signal or the like, determination processing is performed even when the arm unit 103 is moving, and with the end of the conductive pattern detection operation as seen from the calculation speed, The determination is also terminated.

  In this example, one dual inspection unit is mounted on the arm unit 103 and moved on the arm unit 103 to inspect a plurality of display devices arranged two-dimensionally (matrix). However, with this display device arrangement, for example, three dual inspection units may be provided in the arm unit 103 so that the inspection can be performed by one-pass movement of the arm unit 103.

  In the above-described embodiment, the sensor is configured by two electrodes as a sensor pair. However, the present invention is not limited to this, and one sensor may be configured by three or more electrodes. For example, a first sensor electrode (disconnection detection) facing the conductive pattern facing the power supply electrode, a second sensor electrode (short circuit detection) facing the conductive pattern adjacent to the conductive pattern facing the first sensor electrode, There is a configuration example of a sensor electrode (noise detection: noise electrode) facing a conductive pattern several patterns away from the conductive pattern.

The above-described embodiments include the following inventions.
(1) With respect to a plurality of conductive patterns arranged on a substrate, an inspection signal composed of the same AC signal is separated by capacitive coupling apart from above at least two conductive patterns separated by a predetermined number of patterns. First and second power supply electrodes to be continuously applied, and first and second capacitively coupled to the two conductive patterns to which the inspection signal is applied and spaced apart from each other to obtain the applied detection signal An inspection unit having a second sensor electrode;
A moving mechanism that moves in a direction crossing the extending direction of the conductive pattern while maintaining a separated state of the power supply electrode and the sensor electrode;
The detection signals acquired by the first and second sensor electrodes from the same conductive pattern are aligned so that there is no phase shift of the applied time difference, and a local signal exceeding a preset threshold value is detected. An inspection signal processing unit to perform,
A defect determination unit that determines a local signal detected from the first and second sensor electrodes by the inspection signal processing unit as an inspection result, and determines that the local signal detected by any one of the sensor electrodes is noise;
A circuit pattern inspection apparatus comprising:

(2) In the inspection unit,
The first power supply electrode and the first sensor electrode; the second power supply electrode and the second sensor electrode; and a second conductive material separated from the first conductive pattern by an arbitrary pattern row. A first noise electrode that is spaced apart above the pattern, and a first inspection unit,
A second power supply electrode and a second sensor that are spaced apart above a third conductive pattern that is separated from the first conductive pattern facing the first power supply electrode by an arbitrary pattern row distance A second inspection unit comprising: an electrode; and a second noise electrode that is disposed above the fourth conductive pattern that is separated from the third conductive pattern by a distance corresponding to an arbitrary pattern row;
The circuit pattern inspection apparatus according to (1), wherein the circuit pattern inspection apparatus is configured as a dual inspection unit.

(3) The first feeding electrode and the second feeding electrode apply the inspection signal by capacitive coupling in the separated non-contact state with respect to the first conductive pattern,
The first sensor electrode and the second sensor electrode acquire the inspection signal by capacitive coupling in the separated non-contact state with respect to the first conductive pattern, and generate the detection signal,
The first noise electrode and the second noise electrode detect noise superimposed on the potential of the second conductive pattern by capacitive coupling in a non-contact state spaced apart above the second conductive pattern. ,
The detection signal sent from the first inspection unit and the second inspection unit is a detection signal obtained by removing the noise from the detection signal detected by the first sensor electrode and the second sensor electrode. The circuit pattern inspection apparatus according to item (2), wherein

(4) In the inspection signal processing unit,
A smoothing unit for performing smoothing processing on at least two detection signals detected by the inspection unit and slowing down the amplitude and fluctuation of each of the detection signals;
A distance axis matching unit that aligns the smoothed detection signal so as to eliminate the time difference, and
A difference value calculation unit that extracts a signal value at an arbitrary interval from the detection signal and generates a respective difference signal according to a difference from the previous signal value in time series,
A small change emphasizing unit that multiplies the difference signals to generate a product signal in which a defect occurrence point where a change occurs in the signal value included in the difference signal is more emphasized;
A spike noise smoothing unit that smoothes and slows down spike noise included in the product signal to generate the defect determination signal;
The circuit pattern inspection apparatus according to item (1), further comprising:

(5) An inspection method for a circuit pattern inspection apparatus for detecting defects in a plurality of conductive patterns arranged on a substrate,
For each of the conductive patterns, an inspection signal consisting of an AC signal is applied at least twice with a time difference,
Detecting the inspection signal propagated through the conductive pattern by capacitive coupling, and obtaining each detection signal;
Aligning the detected signals so as to eliminate the time difference, performing a product operation that multiplies the detected signals, and generating a defect determination signal that emphasizes the defect location in the detected signal,
An inspection method for a circuit pattern inspection apparatus, wherein a conductive pattern having a defect is detected using a predetermined determination threshold for the defect determination signal.

(6) A substrate on which a plurality of conductive patterns are formed in a row is an inspection target,
A first sensor pair comprising a first power supply electrode and a first sensor electrode facing each other with respect to the first conductive pattern of the conductive patterns;
A second sensor pair comprising a second power supply electrode and a second sensor electrode facing each other with respect to a second conductive pattern spaced a predetermined number of patterns from the first conductive pattern; ,
A moving unit that holds the first sensor pair and the second sensor pair, moves the conductive pattern so as to cross the rows of the conductive patterns, spaced apart from each other by a certain distance above the conductive patterns;
During the movement of the first sensor pair and the second sensor pair by the moving unit, the same inspection signal consisting of an AC signal is supplied to the first feeding electrode and the second feeding electrode, An inspection signal supply unit that sequentially applies the inspection signal to the respective conductive patterns in which the first power supply electrode and the second power supply electrode are oppositely capacitively coupled;
On each signal of the first detection signal and the second detection signal obtained by the first sensor electrode and the second sensor electrode, which are capacitively coupled to the conductive pattern to which the inspection signal is applied, respectively. A distance axis matching unit that performs distance axis matching to move any detection signal by the distance so that the positions of the conductive patterns in
A difference value calculation unit that extracts a signal value at an arbitrary interval from the detection signal and generates a difference signal in each of the first and second detection signals based on a difference from the previous signal value in time series, and
A small change emphasizing unit that multiplies the difference signals to generate a product signal that further emphasizes local changes in the signals included in the difference signals;
A defect determination unit that compares the product signal with a predetermined determination reference value to determine the presence or absence of defects in the conductive pattern;
A circuit pattern inspection apparatus comprising:

  DESCRIPTION OF SYMBOLS 1 ... Circuit pattern inspection apparatus, 2 ... Dual inspection part, 3 ... Moving mechanism, 4 ... Drive control part, 5 ... Inspection signal processing part, 6 ... Control part, 7 ... Input part, 8 ... Display part, 9 ... Memory, DESCRIPTION OF SYMBOLS 11 ... Inspection signal supply unit, 12 ... Sensor unit, 13 ... Inspection signal supply part, 14 ... Smoothing part, 15 ... Distance axis matching part, 16 ... Difference value calculation part, 17 ... Minute change emphasis part, 18 ... Spike noise Smoothing unit, 19 ... CPU, 20 ... defect determination unit, 21a, 21b ... feed electrode, 22,23 ... sensor pair, 22a, 23a ... sensor electrode, 22b, 23b ... noise electrode (sensor electrode) 100 ... substrate, 101 ... conductive pattern, 103 ... arm portion, 104 ... guide member.

Claims (5)

The inspection target is a substrate on which a plurality of conductive patterns are formed in a row,
A first sensor pair comprising a first power supply electrode and a first sensor electrode facing each other with respect to the first conductive pattern of the conductive patterns;
A second sensor pair comprising a second power supply electrode and a second sensor electrode facing each other with respect to a second conductive pattern spaced a predetermined number of patterns from the first conductive pattern; ,
A moving unit that holds the first sensor pair and the second sensor pair, moves the conductive pattern so as to cross the rows of the conductive patterns, spaced apart from each other by a certain distance above the conductive patterns;
During the movement of the first sensor pair and the second sensor pair by the moving unit, the same inspection signal consisting of an AC signal is supplied to the first feeding electrode and the second feeding electrode, An inspection signal supply unit that sequentially applies the inspection signal to the respective conductive patterns in which the first power supply electrode and the second power supply electrode are oppositely capacitively coupled;
With respect to the first detection signal and the second detection signal acquired by the first sensor electrode and the second sensor electrode at the same time by capacitively coupling to the conductive pattern to which the inspection signal is applied, respectively. A defect candidate is selected by comparing a predetermined criterion value, and further, any of the detection signals is selected so that the positions of the conductive patterns on the first detection signal and the second detection signal coincide with each other. a test signal processor having a distance off-axis matching unit for performing distance axis matching moving the position,
The defect candidates in the first detection signal and the second detection signal in which the positions of the conductive patterns are matched are compared with each other, and the defect candidates that are commonly present in the same pattern position are determined as true defects in the conductive pattern. A defect determination unit that performs a first determination to determine:
A circuit pattern inspection apparatus comprising: The inspection signal processing unit
In addition to the distance axis matching unit,
A signal value is extracted at an arbitrary interval from the first detection signal that is matched with the distance axis, and is arbitrarily selected from the first difference signal based on the difference from the previous signal value in time series and the second detection signal. A difference value calculation unit that extracts a signal value at an interval of and generates a second difference signal based on a difference from the previous signal value in time series,
A product signal obtained by multiplying the first difference signal and the second difference signal and making the change in the signal value larger by the product of the defect candidates composed of the changed signal values included in these difference signals. A small change emphasis part to be generated;
With
2. The defect determination unit according to claim 1, wherein the defect determination unit determines, as a second determination, a defect candidate included in the product signal that exceeds a predetermined determination threshold as a true defect of the conductive pattern. Circuit pattern inspection device. In the circuit pattern inspection apparatus,
The first sensor pair has a first noise electrode that is spaced apart above a third conductive pattern that is separated from the first sensor electrode by an arbitrary number of patterns, and
The second sensor pair includes a second noise electrode that is spaced apart above a fourth conductive pattern that is separated from the second sensor electrode by an arbitrary number of patterns. The circuit pattern inspection apparatus according to 1. A substrate on which a plurality of conductive patterns are formed in a row is used as an inspection target, and is arranged in parallel with a predetermined number of patterns in a direction intersecting the row of conductive patterns for detecting a conductive pattern having a defect. An inspection method for a circuit pattern inspection apparatus comprising an inspection unit composed of at least two pairs of power supply electrodes and sensor electrodes,
The inspection unit is moved in a direction crossing the column, and the same inspection signal composed of an AC signal is sequentially applied from each of the feeding electrodes to different conductive patterns separated by capacitive coupling,
A first detection signal and a second detection signal are simultaneously obtained from the sensor electrodes by capacitive coupling of the inspection signals propagated through the respective conductive patterns to which the inspection signals are applied;
For the first detection signal and the second detection signal, a defect candidate is selected by comparison with a predetermined criterion value,
The distance axis matching is performed by moving the position of one of the detection signals so that the positions of the conductive patterns on the first detection signal and the second detection signal match.
The defect candidates in the first detection signal and the second detection signal in which the positions of the conductive patterns are matched are compared with each other, and the defect candidates that are commonly present in the same pattern position are determined as true defects in the conductive pattern. A method for inspecting a circuit pattern inspection apparatus, wherein the first determination is performed. In determining the true defect of the conductive pattern,
A signal value is extracted at an arbitrary interval from the first detection signal, both of which are aligned by the distance axis matching, and the first difference signal from the difference from the previous signal value in time series, and the second A signal value is extracted from the detection signal at an arbitrary interval, and a second difference signal is generated from the difference from the previous signal value in time series, respectively.
Multiplying the first difference signal and the second difference signal to generate a product signal in which the change in signal value is larger by the product of the changed signal values included in these difference signals,
5. The circuit pattern inspection apparatus inspection according to claim 4, wherein a second determination is made to determine a defect candidate included in the product signal exceeding a predetermined determination threshold as a true defect of the conductive pattern. Method.

Images