KR101276970B1 - Circuit pattern inspection device and method thereof - Google Patents

Abstract

An object of the present invention is that in a circuit pattern inspection apparatus using an electrode capacitively coupled to a conductor pattern in a non-contact manner, as the conduction pattern of the inspection target becomes finer, the inspection signal value obtained becomes smaller and the defect determination becomes difficult.
The circuit pattern inspection apparatus moves an inspection section having two pairs of sensor pairs spaced apart from each other, applying an inspection signal composed of an alternating current signal to each conductive pattern by capacitive coupling, and further inspecting the inspection signal propagating the conductive pattern. Detected by capacitive coupling, the inspection signal is detected from each conductive pattern by inspection by one movement, the defect candidates are selected by comparing these detection signals with the determination reference value, and the conductive pattern in each inspection signal. By matching the positions of, the defect candidates are compared with each other, and a conductive pattern having a defect candidate in common at the same pattern position is determined as defective.

Description

Circuit pattern inspection device and inspection method {CIRCUIT PATTERN INSPECTION DEVICE AND METHOD THEREOF}

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

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

As a conventional method of inspecting a conductive pattern, for example, as described in Patent Literature 1, the pinchers of the inspection probes are brought into contact with both ends of the conductive pattern to apply a DC test signal from one inspection probe, and the other. A contact type inspection method (pin contact method) is known which detects a DC test signal propagated from a test probe of and detects the presence of disconnection and short circuit by the presence or absence of the detection signal.

As another inspection method, Patent Document 2 applies an AC inspection signal from one inspection probe while moving at least two inspection probes close to the conductor pattern and moving in a state of capacitive coupling with the conductor pattern in a non-contact manner. The inspection probe detects an alternating current inspection signal propagating the conductor pattern. Due to the change in the waveform of the detection signal, the presence or absence of disconnection and short circuit in the conductive pattern is examined.

[Patent Document 1] Japanese Patent Application Laid-Open No. 62-269075 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-191381

The display device described above is required to have a larger screen size, a larger screen size, a more compact display screen, and a smaller display pixel. For this reason, conductive patterns, such as a drive wiring and a signal line, of a display pixel become long and refine | miniaturize at the same time.

In the case of inspecting a plurality of conductive patterns, in the inspection probe contacting the pincher proposed in Patent Document 1, as the first method, the inspection probe is slid so as to cross the arranged conductive pattern, and the inspection is performed sequentially. Alternatively, as the second method, the same number of test probes as the number of conductive patterns can be arranged to contact the test probes at once, or as the third method, the test probes can be selectively contacted with the test probes while moving up and down. Is moving.

When the inspection probe is slid, the pin tip moves in contact with the conductive pattern, so that damage due to peeling or damage becomes a problem. In addition, even when the inspection probe is brought into contact with the conductive pattern without sliding, damage such as damage caused by pressure applied to the conductive pattern is caused by the contact of the pin tip. In addition, in the case where the contact operation and movement of the inspection probe are to be automated by using a program or the like, the position control becomes less easy as the conduction pattern becomes thinner and the wiring interval becomes smaller.

In addition, in the inspection apparatus using an electrode which is capacitively coupled to a conductive pattern in a non-contact manner, as the surface area of the conductive pattern facing the electrode is reduced, the value of the detected inspection signal is also reduced. If the value of the test signal applied to the conductive pattern is increased, the test signal to be detected is also increased, but with the miniaturization of the conductive pattern, the allowable test signal value is also reduced. The detection signal includes a noise superimposed from the outside in addition to the inspection signal and is detected. For this reason, skill level is required to determine whether the test signal is noise, or setting of the reference value becomes difficult when performing computer judgment.

In addition, when the inspection which moved to one inspection part board | substrate is performed with respect to the test | inspection board | substrate, one detection signal is obtained. In the case where the determination is made with only one detection signal, the threshold value is strictly set so that the presence or absence of a defect can be determined from the slight signal change, but at the same time, the noise component that may be included in the detection signal is also determined. It is not possible to determine whether the obtained judgment result is only true defects. Therefore, the 2nd test | inspection is performed again on the same conditions, and the obtained 2nd test result is compared with the 1st test result, and the defect is confirmed. For this reason, in order to obtain an accurate test result, the test object must be tested at least twice under the same test conditions. In this inspection method, in order to obtain an accurate inspection result, time for performing two times of inspection is consumed, and therefore, it is not easy to shorten the inspection time. In addition, when time becomes empty between the 1st test and the 2nd test, it is not easy to test on the same test condition.

Therefore, according to the present invention, each conductive pattern arranged on a substrate is detected multiple times using a plurality of sets of sensors in time series, and a determination signal multiplying the detected signals is generated, and appropriateness of good and poor of the conductive pattern is obtained. An object of the present invention is to provide a circuit pattern inspection apparatus that realizes the determination.

In order to achieve the said objective, embodiment which concerns on this invention makes the board | substrate with which the some conductive pattern formed in the column shape to be a test object, and the 1st feed electrode which opposes all with respect to the 1st conductive pattern in the said conductive pattern And an opposing second feed electrode and a second sensor electrode with respect to the first sensor pair including the first sensor electrode and the second conductive pattern in which the distance of the predetermined pattern moisture is dropped from the first conductive pattern. A moving part for holding a second sensor pair provided, the first sensor pair and the second sensor pair, spaced apart at a predetermined distance above the conductive pattern, and moving to cross the columns of the conductive pattern; During the movement of the first sensor pair and the second sensor pair by the moving unit, the same test signal composed of an AC signal is supplied to the first feed electrode and the second feed electrode, and the first feed An inspection signal supply unit for sequentially applying the inspection signal to each conductive pattern having a pole coupled to the second feed electrode, and the first sensor capacitively coupled to each of the conductive patterns to which the inspection signal is applied; A defect candidate is selected for the first detection signal and the second detection signal acquired by the electrode and the second sensor electrode in comparison with a predetermined determination reference value, and further, on the first detection signal and the second detection signal. An inspection signal processing unit for performing distance axis matching for shifting the position of any one of the detection signals so that the positions of the conductive patterns on the image coincide with each other, and the first and second detection signals in which the positions of the conductive patterns match. Comparing the defect candidates of each other, and determining a defect candidate commonly present at the same pattern position as a true defect of the conductive pattern; Provided is a circuit pattern inspection apparatus including a defect determination unit that performs one determination.

In addition, at least two sets of power feeds arranged at a distance of a predetermined number of patterns in a direction intersecting a column of the conductive pattern for detecting a conductive pattern having a defect as a test target for a substrate having a plurality of conductive patterns formed in a column shape. An inspection method of a circuit pattern inspection device having an inspection portion composed of a pair of electrodes and a sensor electrode, the inspection method comprising: moving the inspection portion in a direction intersecting the column to separate the same inspection signal composed of an AC signal from each of the feed electrodes; The first detection signal and the second detection signal from the sensor electrode are respectively applied by the capacitive coupling to the conductive pattern sequentially and the capacitive coupling of the inspection signal propagating the respective conductive patterns to which the inspection signal is applied. Is determined, and a predetermined determiner for the first detection signal and the second detection signal Compare the values to select a defect candidate, move the position of any one of the detection signals so as to match the position of the conductive pattern on the first detection signal and the second detection signal, and perform distance axis matching, Circuit pattern inspection for comparing the defect candidates in the first detection signal and the second detection signal in which the position of the pattern is matched and determining the defect candidates commonly present in the same pattern position as true defects in the conductive pattern. Provides a method of inspection of the device.

According to the present invention, for each conductive pattern arranged on a substrate, a plurality of sets of sensors are detected in time series, and a determination signal multiplying the detected signals is generated to generate an appropriate defect of good and poor of the conductive pattern. A circuit pattern inspection apparatus for realizing the determination can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the conceptual structure of the dual inspection part of the circuit pattern inspection apparatus which concerns on this invention.
2 (a) and 2 (b) are diagrams for explaining the determination of the presence or absence of a defect in the circuit pattern inspection device.
3 is a block diagram showing an overall configuration of a circuit pattern inspection apparatus according to the present embodiment.
4 is a diagram illustrating a conceptual configuration of a dual inspection unit of a circuit pattern inspection apparatus.
FIG. 5A is a diagram showing a detection signal by the dual channel electrode in the inspection signal processing unit, and FIG. 5B is a diagram showing a signal subjected to smoothing processing to the detection signal, and FIG. 5C. Is a diagram showing a detection signal subjected to a distance axis matching process.
FIG. 6A is a diagram showing a difference signal obtained by taking a difference between the detection signals subjected to distance axis matching, and FIG. 6B is a multiplication signal obtained by emphasizing a small change by multiplication with respect to the difference signal. Fig. 6C is a diagram showing a signal obtained by smoothing spike noise in a product signal.
7 is a diagram for explaining measurement in a circuit pattern inspection apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings.

The circuit pattern inspection apparatus which concerns on this invention is a member separate from the board | substrate for detecting the disconnection of a plurality of rows of conductive patterns (wiring pattern), or the defect pattern of a short circuit in the manufacturing process, for example on the board | substrate made of glass. Inspection device. The conductive pattern to be inspected is, for example, circuit wiring used in a liquid crystal display panel, a touch panel, or the like, and conductive patterns arranged in parallel in a plurality of columns, and one end side of all conductive patterns are connected by short-circuit bars. It is a conductive pattern of a comb shape. In addition, as long as the position of a pattern can be determined, each electrically conductive pattern formed on a board | substrate can be examined even if it is not arrange | positioned at equal intervals. Moreover, when the dual inspection part mentioned later moves, if it is a pattern which can oppose a feed electrode and a sensor electrode on the same conductive pattern, even if there exists curvature and a change of width in the middle of a conductive pattern, it can examine equally. In addition, in the following description, in order to make it easy to understand, the conductive pattern formed in linear column shape at regular intervals is demonstrated as an inspection object.

1 is a diagram illustrating a conceptual configuration of a dual inspection unit of a circuit pattern inspection apparatus according to the present invention. FIG.2 (a), (b) is a figure for demonstrating the determination of the presence or absence of the defect in a circuit pattern inspection apparatus.

As shown in FIG. 1, the circuit pattern inspection apparatus 1 is a dual inspection unit formed at a predetermined distance apart from a plurality of rows of conductor patterns 101 formed on a substrate 100 having insulation such as a glass substrate. (2), an inspection signal supply section 13 for supplying an inspection signal composed of alternating current to the dual inspection section 2, and an inspection signal processing section 5 for performing signal processing described later on detection signals detected from the dual inspection section 2; ), A defect determination unit 20 provided in a control unit (control unit 6 shown in FIG. 2) to be described later, and a display unit 8 for displaying inspection information including inspection results.

The dual inspection part 2 has two test | inspection parts which consist of a pair of a feed electrode and a sensor electrode. Specifically, the dual inspection unit 2 includes an inspection signal supply unit 11 having a power supply electrode 21 (21a, 21b) for supplying (applying) the inspection signal to the conductive pattern 101, and a conductive pattern. It consists of the sensor unit 12 provided with the sensor electrodes 22 and 23 which detect the test | inspection signal supplied to 101 as detection signal SO. In this example, the power supply positioned in both the first inspection section made up of the feed electrode 21a and the sensor electrode 22 located above the same conductor pattern and the conductive pattern located above the distance of several patterns from the first inspection section. It consists of a 2nd test | inspection part which consists of the electrode 21b and the sensor electrode 23. As shown in FIG. The feed electrode 21b and the sensor electrode 23 are also located above the same conductor pattern.

The test signal supply unit 13 is applied to the power supply electrode 21a and the power supply electrode 21b at each of the test signals of AC having the same voltage value and the same frequency at the same cycle timing. The feed electrodes 21a and 21b are capacitively coupled to the conductive patterns 101 facing each other, and apply an alternating inspection signal. These inspection signals are acquired by the sensor electrodes 22 and 23 which propagate the conductive pattern 101 and are capacitively coupled to each other. The test signal may be a signal propagated by capacitive coupling, and may be a signal of a square (pulse) wave as well as an alternating current of a sine wave.

These units 11 and 12 are in the state of applying the test signal to the conductive pattern 101 from the feed electrodes 21a and 21b by the moving mechanism 3, and from the conductive pattern 101 to the sensor electrode. In the state where (22, 23) detects the inspection signal, it is moved so as to intersect (cross) the rows of the conductive patterns while maintaining the same separation distance (measurement gap) above the pattern. In addition, the inspection signal supply unit 11 and the sensor unit 12 may be disposed apart from each other (for example, at both ends of the conductive pattern) on the substrate to be inspected as long as the conductive pattern and the feed electrode and the sensor electrode face each other. Conversely, you may arrange | position to the position which adjoins. This is because since the dual inspection unit 2 detects a change in the detection signal by capacitive coupling, the capacitance in the conductive pattern appears as a change in the detection signal due to disconnection, unlike when normal.

The 1st inspection part and the 2nd inspection part comprised in this way test | inspect each of the board | substrate 100 used as an inspection object integrally by one scanning movement, respectively, and it is 1 for every one conductive pattern 101. The test is performed once, and each of the detected signals S0a and S0b includes the test results for the same conductive pattern. In other words, when viewed from the inspection unit side, two results can be obtained by one inspection, and when viewed from the conductive pattern side, two inspections are performed with a slight time difference.

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

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

The sensor electrodes 22 and 23 pass the pattern upwards, and the inspection signal propagated to the conductive pattern 101 is detected as the detection signal S0a from the sensor electrode 22 and the detection signal S0b from the sensor electrode 23. Is detected. Therefore, two inspection results can be obtained for one conductive pattern 101. Since these inspection results are shifted only by the distance between sensors, these inspection results are matched by the distance axis matching mentioned later. The distance axis matching here means that the distance between the sensor electrode 22 and the sensor electrode 23 is separated by several patterns. Therefore, in the two detection data (detection signals), A misalignment is occurring. To compare them, one or both of the detection data are brought close to each other so as to eliminate the difference in distance, and the same conductive pattern is moved on the axis so as to match.

In FIG. 2 (b), each determination signal shown in FIG. 2 (a) is moved in the horizontal axis direction to match the pattern position on the vertical axis.

First, detection signals S0a and S0b are sent to the inspection signal processing unit 5. In the test signal processing unit 5, noise components are removed from the amplified and amplified detection signals of the detection signal as needed, and determination signals Sja and Sjb are generated from the test signals S0a and S0b, and the defect determination unit 20 is performed. Is sent out.

As shown in Fig. 2A, the defect determination unit 20 first compares the same reference signal serving as a predetermined determination criterion with respective determination signals Sja and Sjb, and the peak value below the reference. Are selected as defect candidates Pa1, Pa2, and Pb1, Pb2. In Fig. 2A, the peak signal below the reference (or not satisfying the reference) is set as a defect candidate, but in the signal detection method, the peak signal above the reference (or exceeding the reference) is detected. May be set as a defect candidate.

As described above, these determination signals Sja and Sjb are arranged so that the distance between the sensor electrode 22 and the sensor electrode 23 is a few patterns apart, as shown in FIG. The pattern position is matched by distance axis matching so that the pattern in the determination signal is at the same position (same detection timing).

Next, the defect candidates Pa1, Pa2 and Pb1, pb2 in the determination signals Sja and Sjb shown in Fig. 2B are compared. In this comparison, the defect candidates Pa2 and Pb1 coincide on the vertical axis. The other defect candidates Pa1 and Pb2 do not have any defect candidates coincident 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 ("first determination"). "). That is, the defect in a conductive pattern is invariant, and even if it examines multiple times, the detection signal which shows the same defect is obtained. On the other hand, noise and the like superimposed on the detection signal are often generated in a short time and in a single time. 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, the defect candidate of the first inspection unit is caused by noise or the like. Judging by the fault of the doctor.

In this embodiment, although it is a test | inspection part comprised by two pairs of a feed electrode and a sensor electrode, it is not limited to two sets of course, You may use a pair of three or more sets of feed electrodes and a sensor electrode if necessary.

In view of the above, according to the dual inspection unit of the present embodiment, the first inspection unit and the second inspection unit inspect each of the first inspection unit and the second inspection unit by an inspection in which the upper side of the inspection target substrate 100 is moved once as viewed from the inspection unit side. Each of the conductive patterns 101 is inspected once, and detection signals S0a and S0b are obtained, respectively. All of these detection signals include the test results for the same conductive pattern, and two results can be obtained by one test. A defect candidate is selected from these detection signals, and the defect candidate which exists in the same position is judged as a true defect in the detection signal which carried out the position alignment of the pattern.

Therefore, by the inspection signal obtained by the one-time detection operation, accurate determination can be realized, and it is possible to obtain a result of the conduction of the conductive pattern from which noise and the like are appropriately removed.

Next, a circuit pattern inspection apparatus according to a second embodiment of the present invention will be described.

3 is a block diagram showing an overall configuration of a circuit pattern inspection device according to a second embodiment. 4 is a diagram illustrating a configuration of a dual inspection unit in the circuit pattern inspection apparatus. In addition, the same code | symbol is attached | subjected to the site | part equivalent to the structural part shown in FIG.

The circuit pattern inspection apparatus 1 includes, at the time of inspection, a dual inspection unit 2 and a dual inspection unit 2 which are set to be spaced apart a predetermined distance above a plurality of rows of conductor patterns 101 formed on the substrate 100 described above. The moving mechanism 3 which maintains the space | interval (non-contacting) state of 2), and moves so that it may cross | intersect above the conductor pattern 101, the drive control part 4 which drive-controls the moving mechanism 3, and the dual inspection part ( 2) the noise signal by the noise electrodes 22b and 23b from the detection signal detected by the inspection signal supply part 13 which supplies the inspection signal which consists of alternating current, and the sensor electrodes 22a and 23a of the dual inspection part 2; Noise canceling units 24 and 25 for generating subtracted detection signals S0 (S0a and S0b), Inspection signal processing unit 5 for performing signal processing to be described later on detection signals S0 (S0a and S0b), and apparatus To control the entirety of and based on the determination signal Sj of the defect from the inspection signal processing section 5 Inspection information including a control unit 6 for performing defect determination of good or bad of a conductive pattern, an input unit 7 including a keyboard, a switch panel, etc. for instructing the control unit 6, and an input instruction or inspection result. It is comprised by the display part 8 which displays.

The dual inspection unit 2 is an inspection signal supply unit 11 for supplying (applying) an inspection signal to the conductive pattern 101, and a sensor unit 12 for detecting the inspection signal supplied to the conductive pattern 101. It is composed. These units are moved by the movement mechanism 3 in the state which kept the same separation distance (measurement gap) upward with respect to the conductive pattern 101. FIG. Although not shown, the moving mechanism 3 is provided with a distance sensor and a height adjusting mechanism for measuring the distance to the conductive pattern 101, and the inspection signal supply unit 11 and the sensor unit 12 during inspection. ), The distance from the conductive pattern is always adjusted to be constant.

As shown in FIG. 3, the test signal supply unit 11 is provided with power feeding electrodes 21a and 21b spaced apart from each other by the same distance above the conductive pattern 101 from which the distance of the pattern sequence is separated. The test signals of the same voltage value and the same frequency are applied to the power supply electrodes 21a and 21b at the same cycle timing, respectively. The electrode width of these power feeding electrodes 21a and 21b is set suitably, and if the test signal can be supplied appropriately, the width of the conductive pattern 101 may be below, and the test signal is applied to an adjacent conductive pattern. Otherwise, it may have more than the width of the conductive pattern 101.

In this embodiment, the sensor unit 12 is provided with sensor pairs 22 and 23 in which two sensor electrodes are paired, respectively.

For example, in the sensor pair 22, one sensor electrode 22a is arrange | positioned so that it may oppose the same conductive pattern upper direction as the power supply electrode 21a. Moreover, the pair of sensor electrodes 22b are arrange | positioned so as to oppose the conductive pattern 101 upper side apart from several patterns from the sensor electrode 22a. This sensor electrode 22b is arrange | positioned above the conductive pattern spaced apart several patterns from the conductive pattern to which the test signal is supplied, and is comprised so that a noise may be detected. In the following description, this sensor electrode 22b is referred to as a noise electrode 22b.

As in the present embodiment, when measuring by capacitive coupling by a non-contact inspection electrode to the inspection object (conductive pattern), there is no absolute reference potential (for example, GND: 0 V) similar to that of a contact sensor. not. Therefore, a noise electrode 22b having the same characteristics as that of the sensor electrode 22a is provided to detect the conductive pattern to which the test signal is not supplied, thereby detecting a signal value in the no signal state, for example, a noise signal. do. By comparing or subtracting the superposed noise from the inspection signal detected by the sensor electrode 22a, an appropriate detection signal is obtained.

The actual detection signal detected by the sensor unit 12 includes not only the periodic noise caused by the wiring pitch in the conductor pattern, but also the mechanism servo noise and the variation of the separation distance generated at the time of movement and the device arranged in the vicinity. Effects such as the influence of the common mode noise (the noise propagating on the ground line) from the circuit are also included.

In the present embodiment, the noise electrode 22b is disposed at a predetermined distance, for example, 2 mm away from the sensor electrode 22a. By this structure, the detection output by the sensor electrode 22a and the detection output by the noise electrode 22b are sent to the test signal processing part 5, and the superimposed noise is subtracted, and the virtual ground potential GND is removed. And noise reduction are performed.

In addition, in this embodiment, although the example which arrange | positioned the test | inspection signal supply unit 11 and the sensor unit 12 at the both ends of the conductive pattern 101 is shown, this arrangement is only shown as an example, In practice, it may be approached and installed. In addition, it is not necessary to exist also at the both ends of the conductive pattern 101 also in an inspection point. In the case where the test signal supply unit 11 and the sensor unit 12 are arranged in close proximity to the base plate as one unit, the test signal supply unit 11 and the sensor unit 12 move upward to cross the conductive pattern above either the center side or either end side. Can be carried out.

In the present embodiment, since the sensor electrodes 22a and 23a and the noise electrodes 22b and 23b detect signal values as large as possible, the sensor electrodes 22a and 23a detect a signal value as large as possible. Have That is, it has the width below the sum (two spaces on both sides) of the width of the conductive pattern 101 and the space of the adjacent pattern. The direction along the conductive pattern is not limited, and the length of the electrode may be appropriately set.

Next, the test signal processing unit 5 will be described.

The test signal processing unit 5 includes a smoothing unit 14, a distance axis matching unit 15, a difference value calculating unit 16, a small change emphasis unit 17, and a spike noise smoothing unit 18. And each electronic circuit. Moreover, the defect determination part 20 in the control part 6 which performs the defect determination with respect to the conductive pattern 101 is used.

The inspection signal processing unit 5 performs a smoothing process for smoothing the input inspection signals S0a and S0b, the above-described distance axis matching process, a difference value calculation process, a small change emphasis process, and a spike noise smoothing process. Are performed sequentially. The inspection signals are subjected to these processes, converted into defect determination signals Sj (Sja, Sjb), and sent to the defect determination unit 20 which performs defect determination on all the conductive patterns 100. The defect determination unit 20 determines the presence or absence of a defect based on the respective determination signals Sja and Sjb, and displays the determination result on the screen of the display unit 8.

The control part 6 is comprised from the CPU (central processing unit) 19 which controls each component of the whole apparatus, the defect determination part 20, and the memory 9 which stores the information regarding a program or data. .

The memory 9 is a general memory and stores, for example, a control program, various arithmetic programs, data (tables), 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, the processing by the respective constituent parts of the test signal processing unit 5 will be described. 7 shows measurement conditions.

FIG. 5A shows the detection signals S0 (S0a, S0b) of the sensor pairs 22, 23, respectively. This detection signal S0 takes the difference of the detection signal (noise signal) by the noise electrodes 22b and 23b from the detection signal by the sensor electrodes 22a and 23a mentioned above, and removes noise and virtual ground potential GND. Is the signal that is made.

In the present embodiment, as described above, since the sensor pairs 22 and 23 are arranged at intervals of a plurality of conductive patterns, as shown in FIG. 4, the conductive patterns 101 on the substrate 100 are formed. In the case where the inspection is conducted in time series by moving upward, a time difference occurs when passing through the same conductive pattern image. For this reason, in detected detection signals S0a and S0b, as shown to A1, A2, A3 of FIG.

When the test signal is applied to the conductive pattern, noise may be introduced separately from the outside, and the noise may be detected by being superimposed on the detection signal. Most of these noises are often applied instantaneously, and if the time difference between two sensor electrodes is detected and the same conductive pattern is detected, the other sensor electrode may be detected even if noise is detected from one sensor electrode. The noise is not detected. Therefore, by setting this time difference, it is possible to confirm whether the detection signal is a change or noise by comparing the detection signals of the two electrodes.

Next, if necessary, a smoothing process is performed on the detection signal to smooth the amplitude and fluctuation of the detection signal. Here, the fluctuation means that the value (voltage value) changes as the whole signal (or center of amplitude) is waved as shown in Fig. 5A. FIG. 5B shows detection signals S1 (S1a, S1b) that have been smoothed by the smoothing unit 14 with respect to the detection signals. A smoothing process is performed using a general smoothing circuit to make the amplitude of the detection signal dull.

Since the smoothed detection signals S1a and S1b still have a time difference (phase difference), as shown in Fig. 5C, the matching processing is performed by matching the phases of the two detection signals by the distance axis matching unit 15. Is carried out. By this matching process, detection signal S2 (S2a, S2b) is shown by A1 shown to Fig.5 (a). In this matching process, since the distance between two sensor electrodes and the moving speed of the sensor electrode at the time of detection are already known, the moving distance difference can be calculated easily. Only one detection signal may be moved by the movement distance difference.

By this matching process, detection signals in the same conductive pattern match. This indicates, for example, that A1 tying the same point of interest shown in Fig. 5A is inclined, but by performing the matching process, A1 is in the vertical direction, indicating that the inclination is lost and coincided.

In addition, the difference value calculating section 16 makes a difference with respect to the matched detection signals S2a and S2b, respectively. Specifically, the difference signal S3 (first difference signal S3a and second difference signal S3b) shown in FIG. 6A is a case where detection signals S2a and S2b are signal values sampled at regular intervals. Is a signal obtained by taking the difference from the previous signal value and plotted with the difference value. For this reason, the output voltage value of a vertical axis | shaft is made smaller than 2 digits compared with FIG. 5C. In addition, by taking the difference of these signals, only the characteristic of the change of the two difference signals S3a and S3b can be extracted, and a matching virtual ground potential GND can be produced. The virtual ground potential eliminates the fluctuation (up and down change of the reference value of the amplitude of the signal) of the entire signal, resulting in a signal of amplitude at a constant reference value (0V).

FIG. 6B shows a multiplication signal S4 in which the small change emphasis unit 17 performs emphasis processing on the difference signals S3a and S3b. This emphasis processing is performed by arithmetic processing (hereinafter referred to as multiplication) by multiplying the difference signal S3a and the difference signal S3b. In the multiplication operation, if there are defective points in the same conductive pattern 101, the difference signals S3a and S3b all change in signal values. Therefore, the multiplication is multiplied (multiplied) so that the change is greater than the unprocessed calculated value. More emphasis will be given. Briefly, for example, if the signal value at the time of normality is 3 and the signal value at the time of a faulty (defective) is 5, it is necessary to perform a satisfactory determination by 2 of the difference.

However, multiplying the signals detected twice from the same conductive pattern as in the present embodiment results in 3x3 = 9 at normal and 5x5 = 25 at failure, which is a comparison between 9 and 25. Due to the difference 16, it is possible to make a determination of acceptance.

According to the measurement result using the measurement conditions by FIG. 7 in this embodiment, the detection signal of the location of A1, A2, A3 shown to FIG. 6B is emphasized.

Next, as shown in Fig. 6C, the spike noise smoothing unit 18 using a general filter or the like performs the smoothing process of the spike noise on the multiplied signal S4. This process slows the steep change in the extreme time and makes the spike noise inconspicuous, so that the change in amplitude as shown in Fig. 6C is smoothed (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 value is appropriately set based on the normal value (range of signals B1 and B2) of determination signal Sj. In this embodiment, as an example, the determination threshold value is set to 0.00012 V which is approximately twice the peak value at the normal time. With respect to the conductive pattern 101 in which signal values A1, A2, and A3 exceeding this determination threshold value are detected, it is determined that three conductive patterns 101 have a defect (disruption) ("second determination"). In addition, the conductive pattern 101 which has a defect can be specified based on the movement distance shown on the horizontal axis of a graph.

As described above, in the circuit pattern inspecting apparatus of the present embodiment, when the feeding electrode 21a to be moved is opposed to the conductive pattern to be inspected, it is capacitively coupled in a non-contact manner, and an alternating inspection signal is applied. At this time, the first detection signal is detected from the sensor electrode 22a opposite to the conductive pattern. In addition, when the feeding electrode 21b to be moved is opposed to the same conductive pattern after lapse of time, it is capacitively coupled in a non-contact manner, and an alternating inspection signal is applied, and at that time, from the sensor electrode 23a facing the conductive pattern. The second detection signal is detected.

Therefore, in the present embodiment, the same conductive pattern is detected twice by at least two pairs of sensor pairs, and the presence or absence of a defect is determined by comparison with the two detection signals that are synchronized.

In addition, in the determination by this comparison, when there are few changes in the detected two detection signals, the product of these first detection signals and the second detection signals is multiplied to significantly emphasize the signal change at the defect point. Generate a decision signal. In the defect determination signal, noise superimposed on the detection signal is removed using the detection signal of the noise electrode.

In addition, in this embodiment, although the example which detected twice with each pair of sensor pairs about each conductive pattern was demonstrated, it is not limited, of course, It detects twice or more times using two or more pairs of sensor pairs. May be performed.

In addition, in the above-mentioned embodiment, although it was a pair of sensor of a sensor electrode and a noise electrode, when a sensor electrode (1st sensor electrode) opposes any conductive pattern, it adjoins a 2nd sensor electrode so that it may oppose an adjacent conductive pattern. By installing in this manner, it is possible to detect not only disconnection defects but also short circuit defects. In this case, the second sensor electrode is not necessarily faced to the adjacent conductive pattern in front, and can be detected only by being caught by a part of the conductive pattern. In addition, in the above-mentioned example, although the emphasis process which took the product of two detection signals is performed, the multiplication operation in two or more detection signals may be sufficient.

In addition, in this embodiment, it is the example which carried out the test | inspection continuously in the state which moved by the moving mechanism 3 by mounting the dual test part 2, in order to improve the test time efficiency (improvement of the test processing speed). . In contrast, it is possible to apply the inspection method of the present invention to an inspection apparatus in which an existing circuit pattern inspection apparatus is equipped with, for example, one sensor pair (sensor electrode and noise electrode) or one sensor (sensor electrode only). Do. That is, the inspection result with time difference can be obtained by performing the step movement which stops a movement for every arranged conductive pattern, and performing an inspection at least 2 times at the time of stopping. By multiplying the inspection signals described above with respect to these inspection results, the same defect determination signal as shown in Fig. 6C can be obtained, and equivalent inspection results can be obtained.

That is, as long as it is possible to acquire a plurality of detection signals with a time difference on one inspection object, it is possible to apply to any inspection device, and equivalent inspection results can be obtained. In addition, although it is not practical, as a simple theory, even if the detection signal does not overlap noise clearly, even if it is the product (SxS) of one detection signal S, the equivalent test result can be obtained. In the multiplication operation, a plurality of times may be performed.

Unlike the present embodiment, even if any coefficient is multiplied with the detection signal, 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 signal of the pattern is multiplied by the same coefficient, when the difference between the detection signals is small, the difference is not very large, and it cannot be said that the determination is easy, and there is no basis in the coefficient. As we deviate, we do not adopt.

Next, the circuit pattern inspection apparatus which mounts the dual inspection part which concerns on 2nd Embodiment shown in FIG. 7 is demonstrated.

Although it was the example implemented using the electronic circuit for the test signal processing part 5 in 1st Embodiment mentioned above, this embodiment implements the signal processing which the test signal processing part 5 performs is application software (high precision defect extraction algorithm). This is an example to realize.

In the present embodiment, first, a smoothing process for smoothing the amplitude and fluctuation of the detection signal obtained by the sensor pairs 22 and 23 is performed (smoothing processing step).

Next, the detection signal obtained by the sensor pair 22 is set to fn, the detection signal obtained by the sensor pair 23 is set to gn, and half of the data scores forming a waveform containing a defect are set to i. In this case, the difference in the number of data of i

[Difference value calculation processing process].

Here, it is assumed that both detection signals include a distance offset (distance of the sequence of conductive patterns) and the number of conductive patterns therebetween is j. At this time, j number of conductive patterns is moved, matching is performed, and the same timing is performed (matching process of distance axis). In other words, the distance axes of both detection signals coincide.

Next, the product of the detection signals f'n and g'n subjected to such a difference and matching process [equation (1)]

As described above, only the steep change indicating a defect point is emphasized (emphasis on small change).

In addition, hn is the sum of time series with the number of data of defect shape 2i,

The spike noise component is smoothed (spike noise smoothing step). In this manner, finally, as shown in Fig. 6C, a defect determination signal including a conductive pattern signal A1, A2, A3 having a defect 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, it becomes 6 times (6σ) of the lowest standard deviation in the normal conductive pattern without a defect, and in practice, the difference in change of the defect portion is 1.96 times.

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

As described above, according to the circuit pattern inspection apparatus equipped with the dual inspection portion, the inspection signal processing portion is constituted by a circuit element by generating a defect determination signal by the defect extraction processing on the detection signal using software (defect extraction algorithm). Even if it does not, the equivalent effect in 1st Embodiment mentioned above can be acquired. Also in the present embodiment, the defect determination signal is generated by the multiplication using two detection signals. However, even if there are two or more detection signals, it is possible to easily cope by rewriting the program.

In the processing of the application software described above, for the smoothing process, for example, a known method such as a smoothing differential method can be used, and a known method such as a smoothing method or an integrated average method can be used for the spike noise smoothing process. have.

In addition, the test signal in each embodiment mentioned above is not limited to the AC signal which consists of a sine wave, but may be a pulse signal. Alternatively, the frequency may be arbitrary, and the desired frequency may be appropriately set in accordance with 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 object.

These display devices are in the middle of a manufacturing process, and the conductive pattern 101 is formed on the board | substrate 100. FIG. The board | substrate 100 is mounted on the test table 102 of the circuit pattern test apparatus 1, and is hold | maintained by the adsorption mechanism not shown so that it may not move during an inspection. In the following description, the test signal supply unit 11 and the sensor unit 12 are called test units.

The inspection part is provided in the arm part 103 of the moving mechanism 3, and these are provided so that sliding is possible with respect to the longitudinal direction of the arm part 103 of the moving mechanism 3, respectively. As a sliding mechanism, the linear motor etc. which are not shown in figure are used. In addition, the movement mechanism 3 is capable of reciprocating in the longitudinal direction of the guide member 104 by the guide members 104 disposed on both end sides of the arm portion 103. 7 shows a state in which each member is in the position of the initial state.

By the instruction | indication of test | inspection start, the test | inspection part waiting by the initial position D0 moves to the position D1 in the arm part 103. With this movement, the arm portion 103 moves in the longitudinal direction of the guide member 104 and faces the position D2. At this time, the inspection unit detects the opposing conductive pattern. In this example, three display devices are inspected until the inspection part 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 of a direction unlike before. The inspection unit inspects the three display devices until the position D4 is reached. After the position D4 is reached, the inspection portion moves to the position D5 in the arm portion 103. Thereafter, the arm portion 103 moves in the longitudinal direction of the guide member 104 to face the position D6. In this movement, the inspection unit inspects three display devices until the position D6 is reached. When the arm part 103 reaches the position D6, the detection operation | movement with respect to the conductive pattern of the display device in this board | substrate is complete | finished. After completion of the inspection, the arm section 103 returns to the initial position, and the inspection section also returns to the position D0.

In addition, in the pass / fail decision of the conductive pattern, the determination process is performed even if the arm unit 103 is moving after acquiring the inspection signal or the like, and the determination is terminated at the same time as the completion of the detection operation of the conductive pattern in view of the calculation speed.

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

In addition, in this embodiment mentioned above, although the sensor is comprised by two electrodes as a sensor pair, it is not limited to this, You may comprise one sensor by three or more electrodes. For example, a 1st sensor electrode (disconnection detection) which opposes the conductive pattern which a feed electrode opposes, a 2nd sensor electrode (short detection) which opposes the conduction pattern adjacent to the conductive pattern which a 1st sensor electrode opposes, and There is an example of the configuration of a sensor electrode (noise detection: noise electrode) facing a conductive pattern spaced apart from this by a few patterns.

Embodiment mentioned above includes the following invention.

(1) A plurality of conductive patterns arranged on a substrate are continuously spaced above at least two of the conductive patterns having a predetermined number of patterns, and capacitively coupled to continuously apply a test signal made of the same alternating current signal. An inspection unit having first and second feed electrodes, first and second sensor electrodes spaced apart from each other above the two conductive patterns to which the inspection signal is applied, and first and second sensor electrodes acquiring the applied detection signal;

A moving mechanism which maintains a spaced state of the feeding electrode and the sensor electrode and moves in a direction crossing the stretching direction of the conductive pattern;

The respective detection signals acquired by the first and second sensor electrodes from the same conductive pattern are matched so that the phase shift of the applied time difference is eliminated so as to detect local signals exceeding a preset threshold value. Inspection signal processing unit,

The defect determination part which judges that the local signal detected by both the sensor electrodes is noise by the said test signal processing part as a test result, and detected the local signal detected from the said 1st and 2nd sensor electrode.

Circuit pattern inspection apparatus comprising a.

(2) in the inspection section,

The first feed electrode and the first sensor electrode,

A first inspection unit having the second feed electrode and the second sensor electrode and a first noise electrode spaced apart from the first conductive pattern above the second conductive pattern in which a distance of an arbitrary pattern heat is separated from the first conductive pattern;

A second feed electrode and a second sensor electrode disposed to be spaced apart above the third conductive pattern in which a distance of an arbitrary pattern heat is separated from the first conductive pattern to which the first feed electrode is opposed; and the third conductive pattern 2nd inspection part which has a 2nd noise electrode arrange | positioned spaced apart above the 4th conductive pattern which dropped the distance of arbitrary pattern heat from the

It is comprised by the dual inspection part provided with the circuit pattern inspection apparatus of said (1) characterized by the above-mentioned.

(3) The first feed electrode and the second feed electrode apply the inspection signal by capacitive coupling to the spaced 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 spaced non-contact state with respect to the first conductive pattern, and generate the detection signal,

The first noise electrode and the second noise electrode are spaced above the second conductive pattern to detect noise overlapping the potential of the second conductive pattern by capacitive coupling in a non-contact state,

The detection signal transmitted from the first inspection unit and the second inspection unit is a detection signal from which the noise is removed from the detection signal detected by the first sensor electrode and the second sensor electrode. The circuit pattern inspection apparatus described in the above section.

(4) in the test signal processing section,

A smoothing unit for performing a smoothing process on at least two detection signals detected by the inspection unit, and for smoothing the amplitude and fluctuation of each of the detection signals;

A distance axis matching unit for matching the smoothed detection signal to eliminate the time difference;

A difference value calculating section for extracting signal values from the detected signals at arbitrary intervals and generating respective difference signals by a difference from the previous signal value in time series;

A small change emphasis unit that multiplies the difference signal and generates a product signal in which a defect occurrence point at which a change occurs with a signal value included in the difference signal is further emphasized;

A spike noise smoothing unit which smoothes and smoothes the spike noise included in the product signal to generate the defect determination signal.

The circuit pattern test | inspection apparatus as described in said (1) characterized by the above-mentioned.

(5) An inspection method of a circuit pattern inspection device for detecting defects of a plurality of conductive patterns arranged on a substrate,

For each of the conductive patterns, a test signal composed of an AC signal is applied at least twice with a time difference set therein,

The detection signal propagating the conductive pattern is detected by capacitive coupling to obtain respective detection signals,

The detected detection signals are matched so as to eliminate the time difference, multiplication is performed by multiplying the detection signals, and a defect determination signal which emphasizes a defect point in the detection signal is generated.

The conductive pattern having a defect is detected with respect to the defect determination signal using a predetermined determination threshold value.

(6) As a test | inspection object, the board | substrate with which the some conductive pattern was formed in columnar form,

A first sensor pair including all of the first feeding electrodes and the first sensor electrodes facing each other with respect to the first conductive pattern in the conductive pattern;

2nd sensor pair which has a 2nd feed electrode and a 2nd sensor electrode which oppose all the 2nd conductive patterns which dropped the distance of predetermined pattern moisture from the said 1st conductive pattern,

A moving part for holding the first sensor pair and the second sensor pair, moving the spacers apart from each other at a constant distance above the conductive pattern to cross the rows of the conductive pattern;

During the movement of the first sensor pair and the second sensor pair by the moving unit, the same test signal composed of an AC signal is supplied to the first feed electrode and the second feed electrode, and the first feed electrode and An inspection signal supply unit for sequentially applying the inspection signal to each conductive pattern to which the second feed electrode is capacitively coupled to each other;

The position of the conductive pattern on each signal of the first detection signal and the second detection signal acquired by the first sensor electrode and the second sensor electrode by capacitive coupling to each of the conductive patterns to which the test signal is applied is A distance axis matching section for performing distance axis matching to move any one detection signal by the distance so as to coincide;

A difference value calculating section for extracting signal values from the detection signals at arbitrary intervals and generating difference signals in the first and second detection signals, respectively, by a difference from the previous signal values in time series;

A micro change emphasis unit for multiplying the difference signal and generating a multiplication signal for further emphasizing a local change of the signal included in the difference signal;

The defect determination part which judges the presence or absence of the defect of a conductive pattern by comparing the said product signal with the predetermined determination reference value.

Circuit pattern inspection apparatus comprising a.

1: circuit pattern inspection device
2: dual inspection unit
3: moving mechanism
4: driving control unit
5: test signal processing unit
6:
7: input unit
8: display unit
9: memory
11: test signal supply unit
12: sensor unit
13: test signal supply unit
14: smoothing unit
15: distance axis matching unit
16: difference value calculation unit
17: smile change emphasis
18: spike noise smoothing unit
19: CPU
20: defect determination unit
21a, 21b: feeding electrode
22, 23: sensor pair
22a, 23a: sensor electrode
22b, 23b: noise electrode (sensor electrode)
100: substrate
101: challenge pattern
103: arm part
104: guide member

Claims (6)

As a test | inspection object, the board | substrate with which the some conductive pattern was formed in columnar form,
A first sensor pair including all of the first feeding electrodes and the first sensor electrodes facing each other with respect to the first conductive pattern in the conductive pattern;
2nd sensor pair which has a 2nd feed electrode and a 2nd sensor electrode which oppose all the 2nd conductive patterns which dropped the distance of predetermined pattern moisture from the said 1st conductive pattern,
A moving part for holding the first sensor pair and the second sensor pair, moving the spacers apart from each other at a constant distance above the conductive pattern to cross the rows of the conductive pattern;
During the movement of the first sensor pair and the second sensor pair by the moving unit, the same test signal composed of an AC signal is supplied to the first feed electrode and the second feed electrode, and the first feed electrode and An inspection signal supply unit for sequentially applying the inspection signal to each conductive pattern to which the second feed electrode is capacitively coupled to each other;
By capacitively coupling the conductive pattern to which the inspection signal is applied, the predetermined determination reference value is compared with respect to the first detection signal and the second detection signal simultaneously acquired by the first sensor electrode and the second sensor electrode. And a distance axis matching unit configured to select a defect candidate and perform distance axis matching to move the position of any one detection signal so that the positions of the conductive patterns on the first detection signal and the second detection signal coincide. Inspection signal processing unit,
Comparing the defect candidates in the first detection signal and the second detection signal in which the position of the conductive pattern is matched, and determining a defect candidate commonly present in the same pattern position as a true defect of the conductive pattern; 1 defect determination unit that determines
Circuit pattern inspection apparatus comprising a. The method of claim 1,
The test signal processing unit,
In addition to the distance axis matching unit,
A first difference signal obtained by taking a signal value at an arbitrary interval from the first detection signal matched with the distance axis, and a difference from a previous signal value in time series, and a signal at an arbitrary interval from the second detection signal; A difference value calculating unit for extracting a value and generating a second difference signal based on a difference from a previous signal value in time series;
The small change emphasis which multiplies the said first difference signal and the said second difference signal, and produces | generates the multiplication signal which made the change of a signal value larger by multiplying the said defect candidates which consist of the changed signal values contained in these difference signals. With wealth,
And the defect determination unit determines a defect candidate included in the product signal exceeding a predetermined threshold determined as a second determination as a true defect of the conductive pattern. The method of claim 1,
In the circuit pattern inspection device,
The first sensor pair has a first noise electrode disposed to be spaced apart above the third conductive pattern in which the arbitrary number of patterns is dropped from the first sensor electrode, and
The said 2nd sensor pair has a 2nd noise electrode arrange | positioned spaced apart above the 4th conductive pattern which dropped arbitrary number of patterns from the said 2nd sensor electrode, The circuit pattern inspection apparatus characterized by the above-mentioned. At least two sets of feeding electrodes arranged side by side with a predetermined number of patterns in a direction intersecting a column of the conductive patterns for detecting a conductive pattern having a defect, the substrate having a plurality of conductive patterns formed in a column shape for inspection; An inspection method of a circuit pattern inspection device having an inspection portion composed of a pair of sensor electrodes,
Move the inspection unit in a direction crossing the column, and sequentially apply the same inspection signal from the respective feed electrodes to another conductive pattern spaced apart from each other by capacitive coupling;
Capacitively coupling the inspection signal propagating the respective conductive patterns to which the inspection signal is applied, respectively, to simultaneously acquire a first detection signal and a second detection signal from the sensor electrode;
A defect candidate is selected by comparing a predetermined determination reference value with respect to the first detection signal and the second detection signal,
The distance axis matching is performed by shifting the position of any one of the detection signals so that the positions of the conductive patterns on the first and second detection signals coincide.
Comparing the defect candidates in the first detection signal and the second detection signal in which the position of the conductive pattern is matched, and determining a defect candidate commonly present in the same pattern position as a true defect of the conductive pattern; 1 The judgment method of the circuit pattern inspection apparatus characterized by the above-mentioned. 5. The method of claim 4,
In determining the true defect of the conductive pattern,
The first difference signal and the second detection signal are extracted from the difference with the signal value immediately preceding the signal value at a predetermined interval from the first detection signal, which is commonly aligned by the distance axis matching. Extract the signal values at random intervals from each other, and generate a second difference signal from the difference from the previous signal value in time series,
Multiplying the first difference signal and the second difference signal, and generating a product signal having a larger change in signal value by multiplying the changed signal values included in these difference signals,
And a second determination for determining a defect candidate included in the product signal exceeding a predetermined determination threshold value as a true defect of the conductive pattern. delete

Images