JP2009069408A - Tft array inspection method and tft array inspecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To specify a defective point on a short line defect, in a TFT array inspection. <P>SOLUTION: A TFT substrate inspection method inspects defects of a TFT array, by applying a voltage on the TFT array of a TFT substrate and detecting secondary electrons obtained by electron beam irradiation. The inspection method includes a line defect detection process for detecting the presence of line defects by applying a first inspection signal on the TFT substrate; a defective point detection process for detecting presence of a defective point, by applying a second inspection signal having a signal pattern different from the first inspection signal on the TFT substrate; a defective point extraction process for comparing the position of the line defect and the position of the defective point, and extracting the defective point on the line defect, as a defective point of the short-line defect. By changing the signal pattern of the inspection signal applied to the TFT substrate, line defect detection and defective point detection can be conducted through switching. It is determined whether the defect position detected by the defective point detection is located inside a detection position detected in the line defect detection by comparing positional coordinates. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a TFT array inspection performed in a manufacturing process of a liquid crystal substrate or the like, and more particularly, to a TFT array drive when performing a TFT array inspection.

  In the manufacturing process of 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 process is included in the manufacturing process, and a defect inspection of the TFT array is performed in this TFT array inspection process.

  The TFT array is used as a switching element for selecting a pixel electrode of a liquid crystal display device, for example. In a substrate including a TFT array, for example, a plurality of gate lines functioning as scanning lines are arranged in parallel, and a plurality of source lines described as signal lines are arranged orthogonal to the gate lines. A TFT (Thin Film Transistor) is disposed in the vicinity of a portion where the lines intersect, and a pixel electrode is connected to the TFT. The liquid crystal display device is configured by sandwiching a liquid crystal layer between a substrate provided with the TFT array described above and a counter substrate, and a pixel capacitor is formed between the counter electrode and the pixel electrode provided in the counter substrate.

  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.)

  The TFT array inspection device inputs a driving signal for inspection to the TFT array, detects the defect by detecting the voltage state at that time, and also detects the defect of the TFT array by observing the display state of the liquid crystal. Can also be done. When inspecting the TFT array by observing the display state of the liquid crystal, in addition to the inspection in the state of the liquid crystal display device in which the liquid crystal layer is sandwiched between the TFT array substrate and the counter electrode, the liquid crystal layer and the counter electrode are By attaching the provided inspection jig to the TFT array substrate, it is possible to inspect in the state of a semi-finished product that does not reach the liquid crystal display device.

Various defects can occur in a TFT array during its manufacturing process. As types of defects, for example, a short-circuit defect (S-Dshort) between the pixel and the source line, a short-circuit defect (G-Dshort) between the pixel and the gate line, and a short-circuit defect between the source line and the gate line. (S-Gshort), there is a disconnection (D-open) between the pixel 12 and the TFT 11. In addition to the above-described defects in each pixel, there is a so-called adjacent defect that occurs between adjacent pixels. As this adjacent defect, for example, a defect between adjacent pixels in the horizontal direction, a defect between adjacent pixels in the vertical direction, a short circuit between adjacent source lines, a short circuit between adjacent gate lines, and the like are known. Here, among these defects, a defect due to a short circuit between lines is referred to as a short line defect.
JP-A-5-307192

  A defect due to a short circuit between lines (hereinafter referred to as a short line defect) usually affects a plurality of pixels connected to the same line because the voltage state due to the defect affects not only the defective pixel but also the line. Are detected in a line along with other pixels connected to. Therefore, the defect detected in this way is detected as a line defect.

  Therefore, when a short line defect is detected, there is a problem that it is impossible to specify which point on the line is a defect point based only on the result of the short line defect.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above problems and to specify a defect point on a short line defect in a TFT array inspection.

  In the inspection of a TFT substrate, a voltage is applied to the TFT array of the TFT substrate, and secondary electrons obtained by electron beam irradiation are detected to inspect defects in the TFT array. According to the signal pattern of the inspection signal applied to the TFT array The detected defect type is different. The present invention makes use of this characteristic to detect line defects using inspection signals with different signal patterns, and then detect defect points using inspection signals with different signal patterns. A certain defect point is detected as a defect point of a short line defect.

  The inspection of the TFT substrate of the present invention includes a method aspect and an apparatus aspect.

  An aspect of the TFT substrate inspection method of the present invention is a TFT substrate inspection method in which a voltage is applied to the TFT array of the TFT substrate and secondary electrons obtained by electron beam irradiation are detected to inspect defects in the TFT array. A line defect detection step of detecting the presence or absence of a line defect by applying a first inspection signal to the TFT substrate and applying a second inspection signal having a signal pattern different from the first inspection signal to the TFT substrate. A defect point detecting step for detecting the presence or absence of a defect point, and a defect point extracting step for comparing the position of the line defect with the position of the defect point and extracting the defect point on the line defect as the defect point of the short line defect; Is provided.

  According to the aspect of the inspection method of the present invention, it is possible to switch between line defect detection and defect point detection by changing the signal pattern of the inspection signal applied to the TFT substrate, and the defect position detected by the defect point detection. However, it is possible to detect whether or not it is in the detected position by detecting the line defect, for example, by comparing the position coordinates.

  In one form of the signal pattern of the inspection signal applied to the TFT substrate, the first inspection signal is a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate, and the second inspection signal is the vertical direction of the TFT substrate or A signal pattern for applying a different voltage to the TFT array arranged in stripes in the horizontal direction is used.

  In another form of the signal pattern of the inspection signal applied to the TFT substrate, the first inspection signal is a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate, and the second inspection signal is applied to the TFT substrate. It is good also as a signal pattern which applies a different voltage with respect to TFT array arranged in a grid | lattice form in the vertical direction and a horizontal direction.

  As described above, the signal pattern of the second detection signal used to detect the defect point is limited to the signal pattern that forms a striped voltage distribution in the TFT array or the signal pattern that forms a grid-like voltage distribution. First, it can be selected according to the type of short line defect in the TFT array.

  Further, the aspect of the TFT substrate inspection apparatus of the present invention applies a voltage to the TFT array of the TFT substrate, detects a voltage state by the voltage application by secondary electrons obtained by electron beam irradiation, A TFT substrate inspection device for inspecting defects, an electron beam source for irradiating the TFT substrate with an electron beam, a detector for detecting secondary electrons emitted from the TFT substrate, and an inspection signal for the TFT array on the TFT substrate And an inspection signal generation unit that generates and applies the defect detection unit, and a defect detection unit that detects defects in the TFT array based on the detection signal of the detector.

  The inspection signal generation unit generates a first inspection signal and a second inspection signal having different signal patterns. The defect detection unit includes a line defect detection process for detecting presence / absence of a line defect based on a detection signal detected when the first inspection signal is applied, and a defect point based on the detection signal detected when the second inspection signal is applied. Each detection process of the defect point detection process for detecting the presence or absence of the defect and the defect point extraction process for comparing the position of the line defect with the position of the line defect and extracting the defect point of the short line defect from the line defect point is performed.

  In one form of the inspection signal generated by the inspection signal generator, an inspection signal having a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate is generated as the first inspection signal, while the vertical direction of the TFT substrate Alternatively, a signal pattern for applying different voltages to the TFT arrays arranged in a stripe pattern in the horizontal direction, or a signal pattern for applying different voltages to the TFT arrays arranged in a grid pattern in the vertical and horizontal directions of the TFT substrate is used. 2 as a test signal. The second inspection signal can be selected according to the type of short line defect in the TFT array.

  According to the present invention, a defect point on a short line defect can be specified in a TFT array inspection.

  According to the aspect of the present invention, when a line defect is detected by applying the first inspection signal, the signal pattern of the inspection signal applied to the TFT array, which is used as the second inspection signal, is simply changed. Thus, the defect point on the short line defect can be specified.

  According to the aspect of the present invention, when the defect type of the short line defect is different, the defect point can be detected by simply switching the signal pattern of the inspection signal applied to the TFT array.

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

  FIG. 1 is a schematic view of a TFT array inspection apparatus of the present invention.

  The TFT array inspection apparatus 1 includes an inspection signal generation unit 4 that generates an inspection signal for array inspection on the TFT substrate 10, a prober 8 that applies the inspection signal generated by the inspection signal generation unit 4 to the TFT substrate 10, and a TFT substrate. A mechanism (2, 3, 5) for detecting the voltage application state of the TFT and a defect detector 6 for detecting a defect of the TFT array based on the detection signal.

  The prober 8 includes a prober frame provided with probe pins (not shown). The prober 8 contacts the electrode formed on the TFT substrate 10 by placing the probe pin on the TFT substrate 10 and applies an inspection signal to the TFT array.

  The mechanism for detecting the voltage application state of the TFT substrate can have various configurations. The configuration shown in FIG. 1 is a detection configuration using an electron beam. An electron beam source 2 that irradiates an electron beam on the TFT substrate 10 and a secondary electron that detects secondary electrons emitted from the TFT substrate 10 by the irradiated electron beam. The secondary electron detector 3 and the secondary electron detector 3 are provided with a signal processing unit 5 that performs signal processing on detection signals from the secondary electron detector 3 and detects a potential state on the TFT substrate 10.

  Since the TFT array irradiated with the electron beam emits secondary electrons corresponding to the voltage of the applied inspection signal, the potential state of the TFT array can be detected by detecting the secondary electrons.

  The defect detection unit 6 detects defects in the TFT array by comparing with the potential state in the normal state based on the potential state of the TFT array acquired by the signal processing unit 5.

  Here, a configuration example is shown in which a TFT array defect is detected using a mechanism (2, 3, 5) that detects the voltage application state of the TFT substrate. However, the TFT substrate constitutes a liquid crystal display device. If there is a display, a liquid crystal is driven by the inspection signal to display a display pattern based on the inspection signal, and this display state is imaged by the image pickup device and image processing is performed on the acquired image to perform defect inspection. The image may be observed visually. In the case where the TFT substrate is provided with only the TFT array, a liquid crystal display device is temporarily formed by providing a liquid crystal layer and a counter electrode on a jig for applying an inspection signal, and a defect is generated as described above. An inspection may be performed.

  The inspection signal generation unit 4 generates an inspection signal inspection pattern for driving the TFT array formed on the TFT substrate 10. This inspection pattern will be described later.

  The scanning control unit 9 controls the stage 7 and the electron source 2 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 source 2 scans the irradiation position of the electron beam by shaking the electron beam irradiating the TFT substrate 10 in the XY direction. The scanning position becomes the detection position.

  The above-described configuration of the TFT array inspection apparatus is an example, and is not limited to this configuration.

  In a TFT array inspection apparatus using an electron beam, the pixel (ITO electrode) is irradiated with an electron beam, and secondary electrons emitted by this electron beam irradiation are detected and applied to the pixel (ITO electrode). The voltage waveform is changed to a secondary electron waveform and imaged by a signal, whereby the TFT array is electrically inspected.

  FIG. 2 is a diagram for explaining a defect generated in each element portion constituting the TFT array. In each part indicated by a broken line in FIG. 2, a short circuit defect (S-Gshort) shown between the source line 15o and the gate line 14e is an example of a short line defect. In addition to this short line defect, a short circuit between adjacent source lines (SSshort) and a short circuit between adjacent gate lines (GGshort) are known.

  In addition to the short line defect described above, FIG. 2 shows a short circuit defect (S-Dshort) between the pixel 12oe and the source line 15e, and a short circuit defect (G−) between the pixel 12eo and the gate line 14e. Dshort) and a disconnection (D-open) between the pixel 12ee and the TFT 11ee.

  In addition to the above-described defect in each pixel, there is an adjacent defect that occurs between adjacent pixels. As this adjacent defect, there are a defect between pixels adjacent in the horizontal direction and a defect between pixels adjacent in the vertical direction.

  In the TFT array inspection of the present invention, a short-circuit defect between the lines is detected among the defects of the TFT array described above.

  Hereinafter, the TFT array inspection procedure of the present invention will be described with reference to the block diagram of FIG. 1, the flowchart of FIG. 3, and the explanatory diagram of FIG.

  First, the inspection signal generation unit 4 generates a first inspection signal and applies it to the substrate 10 via the probe 8. The first inspection signal is a signal pattern in which the same voltage is applied to all pixels of all TFT arrays on the TFT substrate (S1). When a short line defect exists in the TFT array, the first inspection signal is applied to inspect the line where the short line defect exists as a line defect.

  The substrate 10 to which the first inspection signal is applied is irradiated with an electron beam from the electron source 2, and a secondary electron beam emitted from the substrate 10 by this electron beam irradiation is detected by the secondary electron detector 3. The signal processing unit 5 performs signal processing on the detection signal detected by the secondary electron detector 3 to obtain an image signal. The defect detection unit 6 detects a line defect based on the image signal acquired by the signal processing unit 5 (S2).

  When a line defect is detected in the line defect detection by the defect detection unit 6 (S3), the inspection signal generation unit 4 generates a second inspection signal and applies it to the substrate 10 via the probe 8. The second inspection signal is a signal pattern that has a signal pattern different from that of the first inspection signal and detects the presence or absence of a defect point (S4). When a defect point exists in the TFT array, the defect point is detected by applying the second inspection signal. The defect point inspected by the application of the second inspection signal is not limited to the defect point of the short line defect, and the defect point due to other factors is detected in the same manner.

  The substrate 10 to which the second inspection signal is applied is irradiated with an electron beam from the electron source 2, and a secondary electron beam emitted from the substrate 10 by this electron beam irradiation is detected by the secondary electron detector 3. The signal processing unit 5 performs signal processing on the detection signal detected by the secondary electron detector 3 to obtain an image signal. The defect detection unit 6 detects a defect point based on the image signal acquired by the signal processing unit 5 (S5).

  When a defect point is detected in the defect point detection by the defect detection unit 6 (S6), the defect detection unit 6 compares the line defect and the defect position of the defect point (S7), and the defect determined as the line defect If the coordinates of the defect position determined as the defect point exist in the position coordinates (S8), the defect point detected by this defect point detection is determined as the defect point of the short line defect (S9).

  In the above process, if no line defect is detected in step S3, or if no defect point is detected in step S6, it is determined that there is no short line defect. Further, in the step of S8, when the coordinates of the defect position determined as the defect point do not exist in the coordinates of the defect position determined as the line defect, this defect point is not caused by the short line defect, (S10).

  Therefore, the TFT array inspection of the present invention includes a line defect detection step by steps S1 to S3, a defect point detection step by steps S4 to S6, and a defect point extraction step by steps S7 to S9.

  FIG. 4 shows each image example obtained in the line defect detection process, defect point detection process, and defect point extraction process of the present invention.

  FIG. 4A shows the position of the defect point A of the short line defect on the TFT array. FIG. 4B schematically shows an image example obtained in the line defect detection step. In the line defect detection step, the short line defect is detected as a line defect L. Since this line defect is detected as a line L including a defect point A of a short line defect, the defect point A cannot be specified.

  FIG. 4C schematically shows an image example obtained in the defect point detection step. In the defect point detection step, defect points b and c due to other factors are also detected in addition to the defect point a acquired by detecting the defect point A of the short line defect. The defect point A of the short line defect cannot be selected only from the detection points a, b, and c detected by this defect point detection.

  4D and 4E schematically show examples of images obtained in the defect point extraction process. 4D schematically shows an image of the defect point A of the short line defect obtained in the defect point extraction process, and FIG. 4E) shows the defect points b and c other than the short line defect obtained in the defect point extraction process. An image is shown schematically.

  The defect point A in FIG. 4D is detected from the defect points A, B, and C by detecting the detection point shown in FIG. 4C existing on the line defect L shown in FIG. Can be extracted. The defect points b and c in FIG. 4E are defect points determined to be other than the defect point A of the short line defect by the defect point extraction process.

  Next, a first inspection signal example applied to the substrate in the line defect detection step will be described with reference to FIGS. 5 and 6, and a second inspection signal example applied to the substrate in the defect point detection step will be described with reference to FIGS. It explains using. FIG. 9A shows an example of pixel operation by the line defect detection process, and FIG. 9B shows an example of pixel operation by the defect point detection process.

  FIG. 5 is a first inspection signal example used in the line defect detection step. 5A and 5B show gate signals, and FIGS. 5C and 5D show source signals. A combination of the gate signals in FIGS. 5A and 5B and the source signals in FIGS. 5C and 5D causes a positive voltage (here 10V) and a negative voltage (here −−) to all pixels of the TFT array. 10v) is applied alternately.

  FIGS. 6A and 6B show the voltage state of the pixel (ITO) generated when the same voltage (here, 10 v and −10 V) is applied to all the pixels. FIG. 9A shows a case where −10 V is applied to all pixels.

  When the TFT array on the TFT substrate is subjected to the defect inspection by the signal pattern for uniformly driving as shown in FIG. 5, for example, when the short line defect shown in FIG. The voltage state of the pixel (ITO) connected to the line where the defect point A is present is different from the voltage state (for example, −10 V) that should be. This voltage state of the pixel (ITO) can detect the secondary electron beam emitted from the pixel.

  FIG. 7 is a second inspection signal example used in the defect point detection step. 7A and 7B show gate signals, and FIGS. 7C and 7D show source signals. By combining the gate signals of FIGS. 7A and 7B and the source signals of FIGS. 7C and 7D, a positive voltage (here, 10v) and a negative voltage are vertically striped with respect to the pixels of the TFT array. (Here, −10 v) is applied alternately.

  FIGS. 8A and 8B show the voltage state of the pixel (ITO) generated when the signal pattern of FIG. 7 is applied. For example, the positive voltage pixel (ITO) and the negative voltage on the TFT array. The pixels (ITO) form a vertical stripe pattern voltage distribution. In this vertical stripe pattern, the pixels in the vertical direction of the TFT array have the same voltage, and the adjacent pixel rows in the horizontal direction have different voltages. This voltage distribution is used for detection of laterally adjacent defects.

  In addition, a voltage is applied so that the voltage distribution formed by the positive voltage pixel (ITO) and the negative voltage pixel (ITO) on the TFT array is a horizontal stripe pattern, and the horizontal pixels of the TFT array have the same voltage. Adjacent vertical pixel columns may use different voltage distributions. This voltage distribution is used for detection of adjacent defects in the vertical direction.

  When a defect inspection is performed on the TFT array on the TFT substrate with a signal pattern that generates a striped voltage distribution as shown in FIG. 7, for example, when a short line defect shown in FIG. The voltage state of the pixel (ITO) at the defect point A of the short line defect is different from the voltage state (for example, −10 V) that should be originally. This voltage state of the pixel (ITO) can detect the secondary electron beam emitted from the pixel.

  Among pixels detected as line defects in FIG. 9A (hatched pixels in the drawing), pixels detected as defect points in FIG. 9B (hatched pixels in the drawing). The defect point of the short line defect is detected by extracting.

  Note that the second inspection signal used in the defect point detection step is as shown in FIGS. 10 and 11 in addition to the example of the striped voltage distribution shown in FIGS. 7, 8A, and 8B. An inspection signal indicating a grid-like voltage distribution may be used.

  10A and 10B show gate signals, and FIGS. 10C and 10D show source signals. 10A and 10B and the source signal shown in FIGS. 10C and 10D, a positive voltage (here, 10v) and a negative voltage in a grid pattern with respect to the pixels of the TFT array. (Here, −10 v) is applied alternately.

  FIGS. 11A and 11B show the voltage state of the pixel (ITO) generated when the signal pattern of FIG. 10 is applied. For example, the positive voltage pixel (ITO) and the negative voltage on the TFT array. The pixels (ITO) form a voltage distribution with a grid pattern.

  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 the schematic of the TFT array test | inspection apparatus of this invention. It is a figure for demonstrating the defect which arises in each element part which comprises a TFT array. It is a flowchart for demonstrating the procedure of the TFT array test | inspection of this invention. It is a figure which shows each image example obtained by the line defect detection process of this invention, a defect point detection process, and a defect point extraction process. It is a figure which shows the 1st test | inspection signal applied to a board | substrate in the line defect detection process of this invention. It is a figure which shows the voltage distribution of the board | substrate by the application of a 1st inspection signal in the line defect detection process of this invention. It is a figure which shows the 2nd inspection signal applied to a board | substrate in the defect point detection process of this invention. It is a figure which shows the voltage distribution of the board | substrate by application of the 2nd inspection signal in the defect point detection process of this invention. It is a figure which shows the operation example of the pixel by the line defect detection process and defect point detection process of this invention. It is a figure which shows the other example of the 2nd inspection signal applied to a board | substrate in the defect point detection process of this invention. It is a figure which shows the voltage distribution of the board | substrate by the application of the 2nd inspection signal of another example in the defect point detection process of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... TFT array inspection apparatus, 2 ... Electron source, 3 ... Secondary electron detector, 4 ... Inspection signal production | generation part, 5 ... Signal processing part, 6 ... Defect detection part, 7 ... Stage, 8 ... Probe, 9 ... Scanning Control unit, 10 ... TFT substrate, 11 ... TFT, 11A ... TFT area, 12 ... Pixel electrode, 13 ... Addition capacitor, 14 ... Gate line, 15 ... Source line.

Claims (6)

A method for inspecting a TFT substrate, in which a voltage is applied to the TFT array of the TFT substrate and secondary electrons obtained by electron beam irradiation are detected to inspect defects in the TFT array,
A line defect detection step of detecting the presence or absence of a line defect by applying a first inspection signal to the TFT substrate;
A defect point detection step of detecting the presence or absence of a defect point by applying a second inspection signal having a signal pattern different from that of the first inspection signal to the TFT substrate;
A defect point extracting step of comparing the position of the line defect with the position of the defect point and extracting a defect point on the line defect as a defect point of a short line defect, Method. The first inspection signal is a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate,
2. The TFT substrate inspection according to claim 1, wherein the second inspection signal is a signal pattern in which different voltages are applied to a TFT array arranged in stripes in a vertical direction or a horizontal direction of the TFT substrate. Method. The first inspection signal is a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate,
2. The TFT substrate inspection according to claim 1, wherein the second inspection signal is a signal pattern in which different voltages are applied to a TFT array arranged in a grid pattern in a vertical direction and a horizontal direction of the TFT substrate. Method. A TFT substrate inspection device that applies a voltage to a TFT array of a TFT substrate, detects a voltage state by the voltage application by secondary electrons obtained by electron beam irradiation, and inspects a defect of the TFT array,
An electron beam source for irradiating the TFT substrate with an electron beam;
A detector for detecting secondary electrons emitted from the TFT substrate;
An inspection signal generator for generating and applying an inspection signal to the TFT array on the TFT substrate;
A defect detection unit that detects a defect of the TFT array based on a detection signal of the detector;
The inspection signal generation unit generates a first inspection signal and a second inspection signal having different signal patterns,
The defect detection unit detects a presence or absence of a line defect based on a detection signal detected when applying the first inspection signal; and
A defect point detection process for detecting the presence or absence of a defect point based on a detection signal detected when the second inspection signal is applied;
A TFT characterized by performing each detection process of a defect point extraction process of comparing the position of the line defect and the position of the defect point and extracting a defect point on the line defect as a defect point of a short line defect Board inspection equipment. The first inspection signal is a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate,
5. The TFT substrate inspection according to claim 4, wherein the second inspection signal is a signal pattern for applying different voltages to the TFT array arranged in stripes in the vertical direction or the horizontal direction of the TFT substrate. apparatus. The first inspection signal is a signal pattern for applying the same voltage to all TFT arrays on the TFT substrate,
5. The TFT substrate inspection according to claim 4, wherein the second inspection signal is a signal pattern for applying different voltages to the TFT array arranged in a grid in the vertical direction and the horizontal direction of the TFT substrate. apparatus.

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