JP2007334262A - Method for detecting defect of tft array substrate, and defect detector of tft array substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a fine defect in a TFT array substrate. <P>SOLUTION: The method for detecting and classifying pixel defects of the TFT array substrate includes a signal acquiring step for acquiring a detection signal from a plurality of detection signal acquiring points in one pixel and a signal processing step for dividing one pixel into a plurality of regions and performing defect judgement in the pixel using the divided region as one unit by using the detection signal in the detection signal acquiring point existing in each divided division processing region. In the signal acquiring step, the pixel is virtually divided into a plurality of divided regions and the detection signal is acquired from at least one detection signal acquiring point in each divided region. Therefore, the detection signal is acquired using at least divided fine region in one pixel as a unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a manufacturing process and an inspection process of a TFT array substrate used for a liquid crystal substrate, an organic EL substrate, and the like, and more particularly to defect detection of a TFT array.

  In a process related to a semiconductor substrate on which a TFT array such as a liquid crystal substrate or an organic EL substrate is formed, a TFT array inspection is performed. The inspection of the TFT array substrate is provided as a TFT array substrate inspection process independently after the TFT array substrate manufacturing process, and may be incorporated in the manufacturing process. In this TFT array substrate inspection, the presence or absence, position, defect type, etc. of the TFT array generated on the TFT array substrate, such as short-circuiting, disconnection, and deposits, are determined and classified.

  The TFT array is used as a switching element for selecting a pixel electrode of a liquid crystal display device or an organic EL display device, for example.

  The defect detection of the TFT array can be performed by observing the display state of the liquid crystal or organic EL. However, when the TFT array is inspected by observing the display state, for example, in a liquid crystal panel, the TFT array substrate and Inspection is performed in a state of a liquid crystal display device in which a liquid crystal layer is sandwiched between the counter electrode. Further, inspecting a semi-finished product that does not reach a liquid crystal display device is performed by attaching an inspection jig having a liquid crystal layer and a counter electrode to the TFT array substrate.

  In defect detection of a TFT array, defect detection can be performed by inputting a drive signal for defect detection into the TFT array and detecting the voltage state at that time. In this TFT array, a scanning line (gate line) or a signal line (source line) is disconnected, a scanning line (gate line) and a signal line (source line) are short-circuited, or a pixel defect due to a characteristic defect of a TFT driving a pixel. In the defect inspection, for example, the counter electrode is grounded, a DC voltage of, for example, −15 V to +15 V is applied to all or part of the gate line at a predetermined interval, and an inspection signal is applied to all or part of the source line. By doing that. (For example, the prior art of patent document 1.)

  A device using an electron beam is known for detecting defects in a TFT array. In TFT array inspection using an electron beam, the pixel array (ITO electrode) is irradiated with an electron beam while driving the TFT array according to the inspection pattern, and secondary electrons emitted by this electron beam irradiation are detected. The voltage waveform applied to the pixel (ITO electrode) is changed to a secondary electron waveform to form an image based on a signal, thereby conducting electrical inspection of the TFT array.

  For example, the voltage state of a pixel is detected by a secondary electron detector, and a multiplier called a correlator determines the normal pixel and defective pixel by multiplying the detection waveform detected by the secondary electron detector with a mask signal. To do. Normal pixels and defective pixels can be distinguished and displayed by contrast on the image display. Here, for example, an ideal waveform obtained from a normal pixel is used as the mask signal.

In the field of flat panel display devices (FPD) using liquid crystal or organic EL, display devices for TVs and PCs are required to have a higher image display speed and a wider viewing angle. In a display device for mobile devices, a fine display is required. In order to realize the demands required for such FPD, in the TFT array substrate constituting the panel display device, high definition to reduce the pixel size, wide field of view by arranging a plurality of image electrodes in one pixel An IPS (In-Plane Switching) system that realizes a corner (for example, Patent Document 2), a pixel shape such as a non-rectangular shape such as a rhombus or a V shape as well as a rectangular shape. Various forms such as a division method by dividing have been proposed.
JP-A-5-307192 JP-A-10-260431

  As described above, various pixel forms such as high definition, IPS method, and pixel shape are applied to the TFT array substrate in order to realize the demands required for the FPD. However, there is a problem that the conventional TFT array inspection method cannot be dealt with by simply applying it.

  In order to detect a minute defect, it is difficult to detect a minute defect of a pixel only by increasing the number of points for obtaining a detection signal in the TFT array substrate. For example, in a defect inspection method in which a pixel is irradiated with an electron beam to detect secondary electrons, it is difficult to detect a minute defect in the pixel simply by increasing the number of irradiated electron beams.

  FIG. 10 is a diagram for explaining an example in which a defective pixel is determined by detecting an electron beam by irradiating the pixel with an electron beam. 10A irradiates eight electron beams in each pixel region of the four pixels 20a to 20d, and uses the detection signals acquired using the electron beam irradiation points 30 as detection signal acquisition points. The defect determination of the pixel 20 is performed.

  For example, in the pixel 20a, among the eight detection signals acquired from the eight electron beam irradiation points 30 in the pixel region, the detection signal acquired from the electron beam irradiation point 31 is determined to be “bad”, and the other When the seven detection signals acquired from the electron beam irradiation point 30 are determined to be “good”, the S / N is 1/8, and this pixel is determined to be “no defect”. Also, regarding the pixel 20c, when two of the eight electron beam irradiation points 30 are determined to be “bad”, the S / N is 2/8, and this pixel is also determined to be “no defect”. The

  On the other hand, when the pixel 20d is determined to be “defective” at 8 of the 8 electron beam irradiation points 30, the S / N is 8/8, and this pixel is “defective”. It is determined.

  In such a determination method, even if the number of electron beam irradiation points 30 is increased, the S / N used for pixel determination is the same, so that a minute defect of the pixel cannot be detected.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-described problems and detect minute defects in a TFT array substrate.

  The present invention improves detection accuracy of detection signal acquisition points for a TFT array by increasing the number of detection signal acquisition points in detection signal acquisition, and in signal processing for performing defect determination, pixels are virtually divided into a plurality of regions. A minute defect is detected by dividing and performing defect determination using the divided area as a unit.

  The present invention includes a TFT array substrate defect detection method, a TFT array substrate defect detection device, a TFT array substrate defect information management system, and a program for causing a computer to execute a program. And two processes of detection signal processing.

  The aspect of the TFT array substrate defect detection method of the present invention is a method for detecting and classifying pixel defects on the TFT array substrate. In this aspect, a signal acquisition step of acquiring a detection signal from a plurality of detection signal acquisition points in one pixel, and a detection signal acquisition point existing in each divided processing region obtained by dividing one pixel into a plurality of regions. And a signal processing step of determining a defect in the pixel by using the detection signal in units of divided regions.

  In the signal acquisition process of the present invention, the pixel is virtually divided into a plurality of divided regions, and a detection signal is acquired from at least one detection signal acquisition point in each divided region. As a result, a detection signal can be acquired in units of at least a divided micro area in one pixel.

  Further, the signal processing step of the present invention selects the detection signal acquisition point existing in the divided area based on the area information of the divided area for dividing the pixel and the position information of the detection signal acquisition point, and acquires the selected detection signal. Defect determination is performed for each divided region by comparing the point detection signal with the determination signal.

  As a result, it is possible to determine a defect in units of at least a divided micro area in one pixel.

  The signal acquisition process of the present invention includes a non-contact excitation process in which the TFT array substrate is excited by irradiating the excitation probe from the excitation source based on the position information of the detection signal acquisition point, and a non-contact excitation from the TFT array substrate. In addition to the configuration including a non-contact detection step for detecting a signal representing the driving state of the obtained TFT, the contact probe is brought into direct contact with the TFT array substrate based on the position information of the detection signal acquisition point, And a contact detection step of detecting a potential representing a driving state of the TFT of the TFT array substrate by this direct contact.

  The non-contact excitation process is an excitation process of either electron beam excitation using an electron beam as an excitation probe or laser light excitation using laser light of a femtosecond laser or a semiconductor wavelength tunable semiconductor laser as an excitation probe. The contact detection step is a detection step of either a step of detecting secondary electrons emitted from the TFT array substrate by electron beam excitation or a step of detecting light emitted from the TFT array substrate by laser light excitation.

  An aspect of a defect detection apparatus for a TFT array substrate according to the present invention is a defect detection apparatus that detects and classifies pixel defects on a TFT array substrate. In this aspect, a signal acquisition unit that acquires a detection signal from a plurality of detection signal acquisition points in one pixel, and a detection signal acquisition point that exists in each divided processing area is divided into a plurality of areas. And a signal processing unit that performs defect determination within the pixel using the detection signal in units of divided regions.

  The signal acquisition unit of the present invention sets the position of at least one detection signal acquisition point in the virtually set divided area in the pixel area, and acquires the detection signal of the set detection signal acquisition point.

  In addition, the signal processing unit of the present invention selects a detection signal acquisition point existing in the divided region based on the region information of the divided region that divides the pixel and the position information of the detection signal acquisition point, and acquires the selected detection signal. The defect determination of the divided area is performed by comparing the signal intensity of the point detection signal with the determination signal.

  The signal acquisition unit obtains from the TFT array substrate by the non-contact excitation unit that irradiates the TFT array substrate with the excitation probe from the excitation source based on the position information of the detection signal acquisition point and excites the TFT array substrate. Or a non-contact detection unit that detects a signal representing the driving state of the TFT, or based on the position information of the detection signal acquisition point, the contact probe is directly brought into contact with the TFT array substrate, and the TFT is brought about by this direct contact. One of the configurations including the detection unit that detects the potential representing the driving state of the TFT of the array substrate, or both configurations can be provided. When both signal acquisition units are provided, the defect determination is performed using the detection signal acquired by one of the signal acquisition units, and the defect determination is performed using the detection signal acquired by both the signal acquisition units. May be performed.

  Examples of the non-contact excitation unit used in the present invention include any one of an electron beam excitation unit using an electron beam as an excitation probe, and a laser beam excitation unit using a femtosecond laser or a semiconductor wavelength tunable semiconductor laser as an excitation probe. An excitation part or both excitation parts can be provided.

  The non-contact detection unit used in the present invention includes a secondary electron detection unit that detects secondary electrons emitted from the TFT array substrate by electron beam excitation, and a light detection unit that detects light emitted from the TFT array substrate by laser light excitation. Either one of the detection units or both of the detection units can be provided, and when both detection units are provided, the detection unit is selectively used, and a plurality of detection signals using both detection units. And the defect determination can be performed using these detection signals.

  In addition, a contact microprobe or the like can be applied to the contact detection unit used in the present invention, and the potential at the contact position can be directly measured by bringing the probe tip into contact with a pixel on the TFT array substrate. .

  Moreover, the defect detection apparatus of this invention can be set as the structure provided with the imaging means which acquires the optical image of at least 1 pixel. As this imaging means, for example, a micro CCD camera can be used, and an optical image of a pixel portion where a detection signal acquisition point exists can be acquired. The acquired optical image can be displayed on the display unit together with the result of the defect determination.

  The aspect of the defect information management system for a TFT array substrate of the present invention is an inspection information management system for managing inspection information of pixels of a TFT array substrate. In this aspect, one pixel is virtually divided into a plurality of divided regions, a signal acquisition unit that acquires a detection signal from at least one detection signal acquisition point in each divided region, and each divided processing region And a signal processing unit that performs defect determination within the pixel using the detection signal of the existing detection signal acquisition point as a unit.

  The system according to the present invention further includes an information management unit that manages pixel position information obtained by the signal acquisition unit and information related to the TFT driving state of the pixel in units of divided regions obtained by the signal processing unit in association with each other. Prepare.

  According to this system, it is possible to collectively manage pixel position information and information regarding the TFT driving state of a minute portion of the pixel in units of divided areas, and to evaluate the TFT array substrate. .

  The aspect of the inspection detection program for the TFT array substrate of the present invention is a program for causing a computer to detect pixel defects on the TFT array substrate. This program extracts at least one detection signal acquisition point existing in the divided region virtually set in the pixel based on the position information of the detection signal acquisition point, and extracts from the detection signal to be processed A signal acquisition process including a step of acquiring the detected signal, and dividing the pixel into a plurality of areas, and dividing the acquired detection signal based on the position information of each divided processing area and the position information of the detection signal acquisition point. A step of reading a detection signal of at least one detection signal acquisition point existing in the region, comparing the read detection signal with a signal for defect determination, and determining a defect in the pixel in units of the divided region based on the comparison result And causing the computer to execute each step of the signal processing step including the step of performing.

  According to the present invention, it is possible to detect a minute defect in a TFT array substrate.

  Further, according to the aspect of the present invention, the detection accuracy of the detection signal acquisition point with respect to the TFT array is improved by increasing the detection signal acquisition point, and a predetermined number of pixels from the TFT array with respect to the positional deviation of the detection signal acquisition point. Detection signals can be obtained.

  Further, according to the aspect of the present invention, it is possible to detect a minute defect by virtually dividing a pixel into a plurality of regions and performing defect determination using the divided regions as a unit.

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

  FIG. 1 is a diagram for explaining an outline of signal acquisition processing and signal processing performed by defect determination according to the present invention. Here, FIG. 1 schematically shows one pixel 20 formed on the TFT array substrate, a divided processing region 21 obtained by virtually dividing the pixel 20, and a detection signal acquisition point 30. Yes.

  The pixel 20 is represented by a solid rectangle, and the division processing area 21 is represented by a broken rectangle. The division processing area 21 is not a physical division of the pixel 20, but is a virtual area for defining a processing range when performing signal processing, and is not necessarily fixed and can be changed. . In addition, the number of divisions and the division shape of the division processing area 21 can be arbitrarily determined. For example, FIG. 1 shows divided processing areas 21A to 21D obtained by dividing the pixel 20 into four, but the number of divisions and the shape of the divided processing areas can be set as necessary. Each divided processing region 21 can be defined by coordinate information on the TFT array substrate, and can be specified together with pixels.

  The detection signal acquisition point 30 is a point for acquiring a detection signal indicating the driving state of the TFT of the portion by non-contact or contact on the TFT array substrate.

  For example, in the acquisition of the detection signal by non-contact, the detection signal acquisition point is excited by the non-contact excitation unit, and the detection signal obtained by the excitation is detected by the non-contact detection unit. As the non-contact excitation unit, for example, any one excitation unit of an electron beam excitation unit using an electron beam as an excitation probe, a laser beam excitation unit using a laser beam of a femtosecond laser or a semiconductor wavelength tunable semiconductor laser as an excitation probe, or Both excitation parts can be provided. The non-contact detection unit is either a secondary electron detection unit that detects secondary electrons emitted from the TFT array substrate by electron beam excitation, or a light detection unit that detects light emitted from the TFT array substrate by laser beam excitation. Or both detectors. When both detection units are provided, the detection unit is selectively used. In addition, a plurality of detection signals can be obtained using both detection units, and defect detection can be performed using these detection signals. it can.

  A contact microprobe can be applied as the contact detection unit. The contact microprobe can directly measure the potential at the contact position by bringing the probe tip into contact with a pixel on the TFT array substrate.

  The outline of defect determination according to the present invention will be described with reference to the flowchart of FIG. The defect determination of the present invention includes signal acquisition processing (S1) and signal processing (S2).

  First, the signal acquisition process will be described. In signal acquisition processing, detection signals are acquired at a plurality of detection signal acquisition points within one pixel, and detection signals are acquired at at least one detection signal acquisition point within a divided processing region in which the pixels are virtually divided. To do.

  In FIG. 1, for example, when a secondary electron obtained from an irradiation position is detected by irradiating a TFT array substrate with an electron beam, the detection signal acquisition point 30 is an electron beam irradiation position. This electron beam irradiation position is determined by irradiating the electron beam while moving the electron beam relative to the TFT array substrate, and the interval between adjacent electron beam irradiation positions is two-dimensional in the x and y directions. Depends on the pitch width of the movement.

  Here, an example in which a total of 16 electron beam irradiations of 4 points in the x direction and 4 points in the y direction are performed within one pixel, and detection signal acquisition points are obtained at 16 points within one pixel. .

  The electron beam is usually irradiated with a predetermined pitch width while scanning the electron beam from a reference point determined on a stage on which the TFT array substrate is placed. At this time, by performing alignment between the stage and the TFT array substrate, it is possible to irradiate the electron beam to a predetermined position of the TFT array substrate.

  However, due to the accuracy of the alignment performed between the stage and the TFT array substrate, the accuracy of scanning the electron beam, etc., there is a positional deviation between the preset point on the pixel and the point where the electron beam is actually irradiated. In some cases, the electron beam is irradiated to a position shifted from a preset point on the pixel, or when the shift amount is large, the pixel is irradiated outside the pixel.

  In the present invention, 16 detection signal acquisition points are defined in one pixel by performing electron beam irradiation at a total of 16 points, 4 points in the x direction and 4 points in the y direction. Accordingly, four detection signal acquisition points are determined in each of the divided processing areas 21A to 21D obtained by dividing one pixel into four.

  In this way, by determining four detection signal acquisition points in one divided processing region 21, even if the electron beam irradiation position is shifted, at least one of the electron beam irradiation positions is Since it is in the divided processing area 21, it is possible to acquire a detection signal from at least one detection signal acquisition point in the divided processing area 21, and avoid a situation in which a detection signal cannot be acquired in the divided processing area 21. it can.

  At this time, by setting the beam diameter of the electron beam, it is ensured that four detection signal acquisition points are obtained in the divided processing region 21 even when the irradiation position of the electron beam is displaced. Can be designed.

  Through the above-described signal acquisition process, a detection signal acquisition point can always be determined and a detection signal can be acquired within a divided processing region virtually divided into pixels.

  Next, signal processing, which will be described with respect to signal processing, divides one pixel and performs defect determination using detection signals of detection signal acquisition points existing in the divided processing regions in each divided processing region.

  In FIG. 1, in the signal processing of the detection signal, the pixel 20 is divided into four, and signal processing for defect determination is performed for each divided processing region, and a determination result is obtained for each divided processing region. This means that, in the defect determination of the pixel 20, the position of the defect can be obtained in a smaller minute range in units of divided processing areas, rather than in a large range in which the defect positions existing in the pixel are in units of pixels. I mean. Further, when the relationship between the test signal or the divided processing region and the defect type is known, the defect type can be specified from the divided processing region.

  By the signal processing described above, defect determination can be performed in a divided processing region virtually divided into pixels, and minute defects can be detected.

  Hereinafter, a configuration example of the TFT array defect detection device 1 of the present invention will be described with reference to FIG. FIG. 3 illustrates an example in which defect determination is performed by detecting secondary electrons obtained by irradiating an electron beam.

  In FIG. 3, the TFT array defect detection apparatus 1 generates an inspection signal for array inspection on the TFT substrate 10 and drives a TFT array, and a driving signal for inspection of the TFT array driving unit 8. A prober 9 to be applied to the TFT array of the TFT substrate 10, a mechanism for detecting the TFT array voltage application state (electron beam source 3, secondary electron detector 4), and for detecting defects in the TFT array based on the detection signal. The signal processing unit 11 that performs the signal processing and the display unit 12 that displays the defect determination result detected by the signal processing unit 11 are provided.

  The prober 9 includes a prober frame provided with probe pins. The prober 9 is placed on the TFT substrate 10 to bring the probe pins into contact with the electrodes formed on the TFT substrate 10 and apply an inspection signal to the TFT array.

  The mechanism for detecting the voltage application state of the TFT substrate can have various configurations. In the detection configuration using an electron beam, an electron beam source 3 that irradiates an electron beam onto the TFT substrate 10, and a secondary electron that detects secondary electrons emitted from each ITO electrode of the TFT array of the TFT substrate 10 by the irradiated electron beam. A signal processing unit 11 for detecting the potential state of each TFT array on the TFT substrate 10 by processing the detection signals of the electron detector 4 and the secondary electron detector 4 is provided.

  The ITO electrode of the TFT array irradiated with the electron beam emits secondary electrons in accordance with the voltage of the applied inspection signal, so that the potential state of the TFT array can be detected by detecting the secondary electrons. Can do. Based on the acquired potential state of the TFT array, the signal processing unit 11 detects a defect in the TFT array by comparing with the potential state in the normal state.

  The TFT array driving unit 8 generates an inspection pattern of an inspection signal for driving the TFT array formed on the TFT substrate 10. As this inspection pattern, for example, an inspection pattern for laterally adjacent defects or an inspection pattern for longitudinally adjacent defects can be used.

  The scanning control unit 6 controls the stage 7 and the electron beam source 3 in order to scan the inspection position of the TFT array on the TFT substrate 10. The stage 7 moves the TFT substrate 10 to be placed in the XY direction, and the electron beam source 3 scans the irradiation position of the electron beam by shaking the electron beam irradiating the TFT substrate 10 in the XY direction.

  The above description shows an example in which defect determination is performed using an electron beam as an excitation probe. However, contact determination is performed using a contact microprobe in addition to noncontact such as performing defect determination using laser light as an excitation probe. Can also be done.

  In a non-contact configuration, a laser beam excitation unit using a femtosecond laser or a semiconductor wavelength tunable semiconductor laser as an excitation probe may be provided in addition to the electron beam excitation unit using the electron beam as an excitation probe. .

  The non-contact detection unit for the non-contact excitation unit emits light emitted from the TFT array substrate by laser beam excitation in addition to the secondary electron detection unit for detecting secondary electrons emitted from the TFT array substrate by electron beam excitation. A light detection unit for detection can be used.

  The configuration including the electron beam excitation unit and the detection unit based on secondary electron detection and the configuration including the laser beam excitation unit and the light detection unit can be either one or both configurations. In addition to a usage pattern that is selectively used, a plurality of detection signals can be acquired using both configurations, and defect detection can be performed using these detection signals.

  A contact microprobe can be applied as the contact detection unit. The contact microprobe directly measures the potential at the contact position by bringing the probe tip into contact with a pixel on the TFT array substrate.

  Next, a configuration example and an operation example of the signal processing unit will be described with reference to the configuration diagram of FIG. 4, the flowchart of FIG. 5, and the data configuration diagram of FIG.

  FIG. 4 shows a configuration example of the signal processing unit. In FIG. 4, the signal processing unit 11 stores in a storage unit (detection signal storage unit 11a, pixel position coordinate storage unit 11b, determination result storage unit 11c, optical image storage unit 11d) for storing various information, and a storage unit. Reading means 11e, 11f for reading out the read data, pixel / divided area reading means 11g, defect determination means 11h, and control means 11i for controlling each means.

  The detection signal storage unit 11a receives and stores the detection signal detected by the signal acquisition unit 2 and the position information of the detection signal acquisition point of this detection signal. The position information of the detection signal acquisition point can be acquired from the scanning controller 6 that controls the stage 7 and the electron beam source 3 to control the irradiation position of the electron beam. FIG. 6A shows an example of data stored in the detection signal storage unit 11a.

  The pixel position coordinate storage unit 11b stores the position coordinates of a pixel and the position coordinates of a divided processing area formed by dividing the pixel. The position coordinates of the pixel and the divided processing area define an area range for specifying this area. FIG. 6B shows the first to fourth divided processing areas and the position information thereof when the pixel is divided into four. The position information of these divided processing areas can be determined by the coordinates of each position of the area, for example. According to the pixel position coordinate storage unit 11b, the coordinates for specifying the position can be read by specifying the pixel or the divided processing area of the pixel.

  The determination result storage unit 11c stores the defect determination result determined by the defect determination unit. FIG. 6C stores the determination result of the defect determination for each divided processing area that divides the pixel into four. The determination result storage unit 11c can store defect types in addition to the presence / absence of defects in each divided processing region, and also stores detection signals used for defect determination. be able to. Moreover, you may memorize | store the information linked with the detection signal stored in the detection signal storage means 11a instead of the detection signal itself.

  In addition, the optical image storage unit 11d stores optical image data picked up by the image pickup means 5 such as a micro CCD camera together with its position information as shown in FIG. 6D, for example.

  The reading unit 11e reads a detection signal corresponding to the position information of the pixel or the pixel division processing area from the detection signal storage unit 11a and sends the detection signal to the defect determination unit 11h. Here, in order to acquire the position information of the divided processing area for dividing the pixel, the pixel divided area reading unit 11g reads the position information of the divided processing area set for the pixel from the pixel position coordinate storage unit 11b. The read means 11e reads the detection signal stored in the detection signal storage means 11a using the position information of the divided processing area read from the pixel divided area reading means 11g.

  The defect determination unit 11h performs defect determination in units of divided processing regions using the detection signal read from the detection signal storage unit 11a by the reading unit 11h. Processing for defect determination is performed, for example, by comparing the read detection signal with a determination signal prepared in advance. The determination signal can be formed based on a detection signal obtained when there is no defect and a detection signal obtained for each defect type. Defect determination can be performed, for example, by extracting a determination signal having a correlation with the detection signal.

  The determination result obtained by the defect determination unit 11h is stored in the determination result storage unit 11c. The determination result stored in the determination result storage unit 11c can be displayed on the display unit 12 by the reading unit 11f.

  The reading unit 11f can read image data corresponding to the pixel related to the determination result from the optical image storage unit 11d. This image data is read out by acquiring position information corresponding to the pixel from the pixel position coordinate storage unit 11b, reading out the image data from the optical image storage unit 11d based on the acquired position information, and reading the read image data and the determination result. In addition, they are displayed on the display means 12.

  In the flowchart shown in FIG. 5, a detection signal is acquired by the acquisition signal unit 2 from the substrate to be inspected (S11). A pixel to be subjected to defect determination is selected (S12), and the selected pixel is selected from the divided processing areas for dividing the pixel (S13).

  With respect to the selected divided processing region, detection signal acquisition points existing in the divided processing region are extracted, and the detection signal of this detection signal acquisition point is read out. The detection signal acquisition point existing in the divided processing area is extracted by reading the position information from the pixel position coordinate storage means 11b by the pixel divided area reading means 11g and from the detection signal storage means 11a based on the position information by the reading means 11e. This can be done by reading (S14).

  The defect determination unit 11h performs defect determination in the divided processing area based on the read detection signal (S15).

  If it is determined that there is a defect in the defect determination, the divided processing area is set as a defective area (S17). If it is determined that there is no defect in the defect determination, the divided processing area is set as a normal area (S18). Remember. The determination result storage unit 11c stores image coordinates, division processing areas, TFT driving state information, and the like (S19).

  By repeating S13 to S19 for the divided processing areas included in the pixel, defect determination is performed for each divided processing area in the pixel (S20), and further, by repeating S12 to S20 for the pixels included in the TFT array substrate, the TFT Defect determination is performed for each pixel in the array substrate (S21).

  FIG. 7 is a diagram for explaining defect determination in a divided processing area in a pixel. FIG. 7A shows the relationship between pixels and divided processing areas and detection signal acquisition points, and FIG. 7B shows defect determination results in accordance with the pixels and divided processing areas.

  FIG. 7A shows four pixels 20a to 20d. Each of the pixels 20a to 20d (area represented by a solid line in the figure) is virtually divided into four division processing areas 21A to 21D (area represented by a broken line in the figure), Detection signals are acquired at four detection signal acquisition points in each of the divided processing regions 21A to 21D.

  For the sake of explanation, in the example shown in FIG. 7A, among the pixels 20a to 20d, the pixels 20a, 20c, and 20d contain defects at positions indicated by A, B, and C, respectively. And

  For example, in the defect determination of the pixel 20a, in the defect determination of the divided processing regions 21A to 21D, two of the four detection signal acquisition points in the divided processing region 21C (detection signal acquisition points indicated by the ground pattern in the drawing) ) Includes a defect (indicated by A in the figure), and the detection signal detected at the detection signal acquisition point in any of the other divided processing areas 21A, 21B, and 21D. Defects shall not be included.

  FIG. 8 is a diagram illustrating a defect example indicated by A in the pixel 20a in FIG. Here, an IPS TFT array substrate having the common electrode 22 and the pixel electrode 23 is shown. In FIG. 8, in the pixel 20a, it is assumed that there is a defect at a position (position A in FIG. 8) corresponding to the divided processing area 21C of the common electrode 22 among the divided processing areas 21A to 21D divided into four. In this case, as shown in FIGS. 7A and 7B, it is determined that “there is a defect” only in the divided processing area 21C of the pixel 20a, and “there is no defect” in the other divided processing areas 21A, 21B, and 21D. Is determined. As a result, in FIG. 7B, defect display is performed in the divided processing area 21C in each area into which the pixel 20a is divided into four.

  In the defect determination of the pixel 20c, in the defect determination of the divided processing areas 21A to 21D, two of the four detection signal acquisition points in the divided processing area 21D (detection signal acquisition points indicated by the ground pattern in the drawing). ) Includes a defect (indicated by B in the figure), and the detection signal detected at the detection signal acquisition point in any of the other divided processing areas 21A, 21B, and 21C. Defects shall not be included.

  FIG. 9 is a diagram illustrating a defect example indicated by B in the pixel 20c in FIG. In FIG. 9, it is assumed that the pixel 20c has a defect at a position (position B in FIG. 9) corresponding to the divided processing area 21D of the pixel electrode 23 among the divided processing areas 21A to 21D divided into four. In this case, as shown in FIGS. 7A and 7B, it is determined that “there is a defect” only in the divided processing region 21D of the pixel 20c, and “there is no defect” in the other divided processing regions 21A, 21B, and 21C. Is determined. Thereby, in FIG. 7B, defect display is performed in the divided processing area 21D in each area into which the pixel 20c is divided into four.

  Further, in the defect determination of the pixel 20d, in the defect determination of the divided processing areas 21A to 21D, the detection signal detected at the four detection signal acquisition points in all of the divided processing areas 21A to 21D (denoted by C in the drawing). ) Is included. As an example in which a defect is determined at all detection signal acquisition points in the divided processing region, for example, a TFT included in a pixel may include a defect.

  In such a case, as shown in FIGS. 7A and 7B, it is determined that “there is a defect” in all the divided processing areas 21A to 21D of the pixel 20d. Thereby, in FIG. 7B, defect display is performed on each of the divided processing areas 21A to 21D divided into four of the pixel 20d.

  According to the present invention, it is possible to perform defect determination on the position of a minute defect in a pixel in units of divided processing areas.

  In addition, according to the present invention, for example, the defect occurrence location and the defect type, such as whether the defect location is a pixel electrode or a common electrode, or whether the defect location is an electrode or a TFT, are classified and evaluated. Can do.

  Further, the defect type can also be determined by an inspection signal applied to the TFT array substrate, and according to the present invention, the defect type and the defect occurrence position are determined from the relationship between the inspection signal and the detection signal acquisition point. Can be determined.

  The present invention can be applied not only to a TFT array inspection process in a liquid crystal manufacturing apparatus but also to a defect inspection of a TFT array provided in an organic EL or various semiconductor substrates.

It is a figure for demonstrating the outline of the defect determination by this invention. It is a flowchart for demonstrating the outline of the defect determination by this invention. It is a figure for demonstrating the example of 1 structure of the TFT array defect detection apparatus of this invention. It is a block diagram for demonstrating the structural example of the signal processing part of this invention. It is a flowchart for demonstrating the operation example of the signal processing part of this invention. It is a data block diagram for demonstrating the operation example of the signal processing part of this invention. It is a figure explaining the defect determination in the division | segmentation process area in the pixel of this invention. It is a figure which shows the example of a defect of a pixel. It is a figure which shows the example of a defect of a pixel. It is a figure for demonstrating the example which irradiates an electron beam to a pixel and determines a defective pixel by secondary electron detection.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Defect detection apparatus, 2 ... Signal acquisition part, 3 ... Electron beam source, 4 ... Secondary electron detector, 5 ... Imaging device, 6 ... Scanning control part, 7 ... Stage, 8 ... TFT array drive part, 9 ... Prober, 10 ... TFT array substrate, 11 ... Signal processing unit, 12 ... Display unit, 20, 20a-20d ... Pixel, 21, 21A-21D ... Divided processing region, 22 ... Common electrode, 23 ... Pixel electrode, 30 ... Detection Signal acquisition point, 31... Electron beam irradiation point.

Claims (13)

A method of detecting and classifying pixel defects on a TFT array substrate,
A signal acquisition step of acquiring detection signals from a plurality of detection signal acquisition points in one pixel;
A signal processing step of dividing the one pixel into a plurality of regions, and using the detection signal of the detection signal acquisition point existing in each divided processing region to determine a defect in the pixel in units of the divided region; A defect detection method for a TFT array substrate, comprising:   2. The signal acquisition step according to claim 1, wherein the signal acquisition step virtually divides the pixel into a plurality of divided regions and acquires a detection signal from at least one detection signal acquisition point in each of the divided regions. TFT array substrate defect detection method. The signal processing step includes
Based on the area information of the divided area for dividing the pixel and the position information of the detection signal acquisition point, the detection signal acquisition point existing in the division area is selected, and the detection signal and the determination signal of the selected detection signal acquisition point are selected. The defect detection method for the TFT array substrate according to claim 1, wherein the defect determination of the divided region is performed by comparing the two. The signal acquisition step includes
A non-contact excitation process for irradiating the TFT array substrate with an excitation probe from an excitation source based on the positional information of the detection signal acquisition point; and
A signal acquisition step comprising: a non-contact detection step of detecting a signal representing a driving state of the TFT obtained from the TFT array substrate by this non-contact excitation;
Alternatively, a signal including a contact detection step of directly contacting a contact probe with the TFT array substrate based on position information of the detection signal acquisition point and detecting a potential representing a driving state of the TFT of the TFT array substrate by the direct contact. Acquisition process,
The defect detection method for a TFT array substrate according to claim 2, wherein the defect detection method is any one of the above. The non-contact excitation step is either electron beam excitation using an electron beam as an excitation probe, or laser beam excitation using a femtosecond laser or a laser light of a semiconductor wavelength tunable semiconductor laser as an excitation probe,
The non-contact detection step is one of a step of detecting secondary electrons emitted from the TFT array substrate by electron beam excitation or a step of detecting light emitted from the TFT array substrate by laser light excitation. The defect detection method for a TFT array substrate according to claim 4. A defect detection device for detecting and classifying pixel defects on a TFT array substrate,
A signal acquisition unit for acquiring detection signals from a plurality of detection signal acquisition points in one pixel;
A signal processing unit that divides the pixel into a plurality of regions and performs defect determination within the pixel using the detection signal of the detection signal acquisition point existing in each divided processing region as a unit. A defect detection apparatus for a TFT array substrate, comprising:   The signal acquisition unit sets the position of at least one detection signal acquisition point in a divided region virtually set in a pixel region, and acquires a detection signal of the set detection signal acquisition point. The defect detection apparatus for a TFT array substrate according to claim 6. The signal processing unit
Based on the area information of the divided area for dividing the pixel and the position information of the detection signal acquisition point, the detection signal acquisition point existing in the division area is selected, and the detection signal and the determination signal of the selected detection signal acquisition point are selected. The defect detection apparatus for a TFT array substrate according to claim 6 or 7, wherein the defect determination of the divided region is performed by comparing the two. The signal acquisition unit
Based on the position information of the detection signal acquisition point, a non-contact excitation unit that excites the TFT array substrate by irradiating the excitation probe from the excitation source;
A configuration comprising a non-contact detection unit for detecting a signal representing a driving state of the TFT obtained from the TFT array substrate by this non-contact excitation,
Or a contact detection unit that directly contacts the TFT array substrate based on the position information of the detection signal acquisition point and detects a potential representing the driving state of the TFT of the TFT array substrate by the direct contact. ,
The defect detection apparatus for a TFT array substrate according to claim 7, comprising one or both of the configurations. The non-contact excitation unit is an excitation of one or both of an electron beam excitation unit using an electron beam as an excitation probe and a laser beam excitation unit using a laser beam of a femtosecond laser or a semiconductor wavelength tunable semiconductor laser as an excitation probe. With splits,
The non-contact detection unit is one of a secondary electron detection unit that detects secondary electrons emitted from the TFT array substrate by electron beam excitation, and a light detection unit that detects light emitted from the TFT array substrate by laser light excitation. The defect detection apparatus for a TFT array substrate according to claim 9, further comprising a detection unit or both detection units.   The defect detection apparatus for a TFT array substrate according to any one of claims 6 to 10, further comprising imaging means for acquiring an optical image of the at least one pixel. An inspection information management system for managing inspection information of pixels of a TFT array substrate,
A signal acquisition unit that virtually divides one pixel into a plurality of divided regions and acquires a detection signal from at least one detection signal acquisition point in each divided region;
Using a detection signal of a detection signal acquisition point existing in each of the divided divided processing areas, and a signal processing unit that performs defect determination in the pixel in units of the divided areas,
An information management unit is provided that associates and manages pixel position information obtained by the signal acquisition unit and information on a TFT driving state of the pixel in units of divided regions obtained by the signal processing unit. , TFT array substrate inspection information management system. A program for causing a computer to detect pixel defects on a TFT array substrate,
A step of extracting at least one detection signal acquisition point existing in a divided region virtually set in the pixel based on position information of the detection signal acquisition point, and a detection signal extracted from the detection signal to be processed A signal acquisition process including a step of acquiring;
The pixel is divided into a plurality of regions, and from the acquired detection signal, acquisition of at least one detection signal existing in the divided region based on position information of each divided processing region and position information of detection signal acquisition points A signal processing step comprising: a step of reading a point detection signal; and a step of comparing the read detection signal with a defect determination signal and determining a defect in the pixel in units of the divided regions based on the comparison result; With
A program for causing a computer to execute defect detection on a TFT array substrate, wherein the computer executes each step.