JP5423664B2 - TFT array inspection equipment - Google Patents

Description

  The present invention relates to a TFT array inspection process performed in the manufacturing process of a liquid crystal substrate or the like, and more particularly to TFT array driving and defect type classification when performing 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 (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 thin film transistor (TFT) is disposed in the vicinity of the portion where the lines intersect, and a drive signal is supplied to the pixel (pixel electrode) through the TFT.

  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 a part of the gate line at a predetermined interval, and a driving signal for inspection is applied to all or a part of the source line. Is performed by applying. (For example, the prior art of patent document 1 and patent document 2.)

  The TFT array inspection apparatus can detect a defect by inputting a driving signal for inspection to the TFT array and detecting the voltage state at that time.

  In a TFT array inspection apparatus such as a liquid crystal array inspection apparatus, as a captured image obtained by imaging on a substrate such as a liquid crystal substrate, an optical captured image obtained by optical imaging, or charging such as an electron beam or an ion beam A scanned image obtained by two-dimensionally scanning the beam on the substrate can be used.

  For example, an inspection signal is applied to the TFT array of the substrate to be inspected to bring the TFT array into a predetermined potential state, and the substrate is scanned by two-dimensionally irradiating a charged beam such as an electron beam or an ion beam. The TFT array is inspected based on a scanned image obtained by scanning.

  In a TFT array inspection apparatus using an electron beam, a pixel (pixel electrode) is irradiated with an electron beam, and secondary electrons emitted by the electron beam irradiation are converted into an analog signal by a photomultiplier and detected. A scanning image is obtained by changing the voltage waveform applied to the pixel (pixel electrode) into a secondary electron waveform to obtain an image, thereby performing an electrical inspection of the TFT array and a defect inspection.

  The TFT array and the pixel of the substrate are formed corresponding to each other, and a specific pixel can be driven by applying a drive signal to the TFT array. The TFT array defect can be detected, for example, by comparing the signal intensity of the acquired scanned image with the signal intensity of the scanned image obtained from a normal TFT array when driven by a drive signal having a predetermined pattern.

JP 2004-271516 A JP 2004-309488 A

  Conventionally, the TFT array is driven by a TFT drive circuit provided outside the substrate. The TFT drive circuit is configured by a shift register including a gate circuit, for example. The shift register sequentially applies drive signals to the gate lines and sequentially drives TFT arrays arranged in an active area such as a panel.

  In recent years, for the purpose of reducing the cost of a panel or the like, a configuration has been proposed in which an external TFT drive circuit is incorporated on a substrate.

  Therefore, in order to improve the yield of the substrate and the panel, it is necessary to inspect and correct not only the defect of the TFT array formed in the active area on the substrate but also the defect of the TFT drive circuit formed outside the active area. It has become.

  Since the conventional TFT array inspection apparatus is configured by applying an inspection signal to the TFT array in the panel portion, which is the active area on the substrate, defects in the TFT drive circuit provided outside the active area on the substrate are eliminated. There is a problem that it cannot be detected.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and to detect a defect in a TFT drive circuit provided outside the active area together with the active area formed on the substrate.

  The present invention is a TFT array inspection apparatus for inspecting a TFT array formed on a substrate. An active area and a TFT drive circuit for driving the active area are provided on a substrate to be inspected by the TFT array inspection apparatus of the present invention, and both are formed of a TFT array.

  The TFT array inspection apparatus according to the present invention includes a TFT drive circuit driver unit that supplies an inspection signal to the TFT drive circuit, an active area, and an image output of the active area obtained by this scanning. A detection unit that detects a driving state of the active area.

  The TFT driver circuit driver of the present invention drives the TFT array of the TFT driver circuit by supplying an inspection signal to the TFT driver circuit provided on the substrate. By driving the TFT array of the TFT drive circuit, the TFT array formed in the active area on the substrate is driven.

  The detection unit of the present invention uses the scanned image of the active area to detect a non-driven part that is not driven on the active area. The non-driven part can be detected based on the signal intensity of the scanned image of the active area. For example, it can be detected by comparing the signal intensity of the scanned image of the active area with the signal intensity in a normally driven state.

  The detection unit detects the non-driving state of the active area and the non-driving state of the TFT drive circuit based on the detected appearance state of the non-driving part. In the detection of the non-driving state, the non-driving state of the TFT driving circuit is detected with priority over the non-driving state of the active area.

  The TFT drive circuit provided on the substrate to be inspected by the TFT array inspection apparatus of the present invention includes a gate circuit. This gate circuit is constituted by a shift register formed by a TFT array.

  The driver section for a TFT drive circuit according to the present invention sequentially drives the gate circuit of the shift register of the TFT drive circuit. The gate circuit sequentially drives the active area according to the driving order of the shift register. The TFT array on the active area is sequentially driven by the TFT drive circuit, and a voltage applied to the source line is applied to the pixel corresponding to the TFT array. The non-driving state of the TFT array can be detected based on the voltage state of the pixel, and it is possible to determine whether the driving circuit or the TFT array in the active area is in a normal state or an abnormal state.

  Since the drive signal of the TFT drive circuit is applied to the TFT array of the drive circuit first and then to the TFT array in the active area, the detection of the non-drive state of the TFT array is performed by detecting the non-drive state of the TFT drive circuit. Detection is prioritized over the non-driven state of the active area.

  Furthermore, the TFT array inspection apparatus of the present invention includes a defect type discriminating unit that discriminates the defect type of the TFT array formed on the substrate.

  The defect type discriminating unit according to the present invention determines that a defect in the active area is present when the non-driving site detected in the scanned image of the active area detected by the detecting unit is a mode that appears in areas separated from each other. However, if it is a form that appears in a continuous or intermittent region, it is determined that the TFT drive circuit is defective.

  Normally, defects in the TFT array that occur in the active area are independent of other TFT arrays, and therefore, non-drive sites that appear on the active area appear as regions separated from each other. Therefore, when the form in which the non-driving site detected in the scanned image of the active area detected by the detection unit appears in a region separated from each other, it is determined as a defect in the TFT array in the active area.

  On the other hand, the TFT array defect generated in the TFT drive circuit stops the drive signal applied to the active area through the gate circuit of the defective part on the shift register, so that the gate line applied through the gate circuit of this defective part is stopped. In addition to the area appearing as a non-driven part on the active area, the drive signal supply is also stopped for the gate circuit behind the defective part, so the area behind the gate line corresponding to the gate circuit of the defective part is also active. Appears as a non-driven part on the area. Therefore, in such a case, if the pattern appears in a continuous or intermittent region, it is determined as a defect in the TFT drive circuit.

  The defect type discriminating unit determines that the non-driven part is a point defect when the non-driven part is a point-like part in the form in which the non-driven part appears in a region separated from each other in the defect type discrimination of the active area. In the case of the shape portion, it is determined as a line defect, and the position of each driven portion is determined as the defect position of the TFT array on the active area.

  Further, the defect type discriminating unit determines that the non-driving part that appears in the continuous area is a planar area or the non-driving part that appears in the intermittent area is intermittent in the linear part in the defect type discrimination of the TFT drive circuit. In the case where the region appears as a result, in the above-described region on the active area, the position on the TFT drive circuit corresponding to the head in the drive order of the TFT drive circuit that drives the region is set in the TFT array of the TFT drive circuit. It is determined as a defect position.

  According to the present invention, the TFT drive circuit driver unit for supplying the inspection signal to the TFT drive circuit is provided, so that the active area and the TFT drive circuit for driving the active area are provided on the substrate to be inspected. Even when both are formed of TFT arrays, defect inspection can be performed not only on the TFT array of the active area but also on the TFT array of the TFT drive circuit.

  Further, according to the present invention, the active area is scanned, and based on the image output of the active area obtained by this scanning, the TFT drive circuit and the detection unit for detecting the drive state of the active area are provided. Based on the detected appearance state of the non-drive part, the non-drive state of the active area and the non-drive state of the TFT drive circuit can be distinguished and detected.

It is a figure for demonstrating the structural example of the board | substrate with which the TFT drive circuit was formed. It is a figure for demonstrating the structure of the TFT array test | inspection apparatus of this invention. It is a figure for demonstrating the structure of the prober frame which applies a drive signal to a board | substrate by the TFT array test | inspection apparatus of this invention. In the TFT array inspection apparatus of this invention, it is a figure for demonstrating the relationship between the TFT drive circuit on a board | substrate, and the driver part for TFT drive circuits. It is a flowchart for demonstrating operation | movement of the TFT array test | inspection apparatus of this invention. It is a figure for demonstrating the example of the scanning image of the active area obtained with the TFT array test | inspection apparatus of this invention in normal time. In the TFT array inspection apparatus of this invention, it is a figure for demonstrating the example of the scanning image of an active area when there exists a defect on an active area. In the TFT array inspection apparatus of this invention, it is a figure for demonstrating the example of the scanning image of an active area when a TFT drive circuit has a defect. In the TFT array inspection apparatus of this invention, it is a figure for demonstrating the example of a scanning image of an active area when there exists a defect on an active area and a TFT drive circuit. It is a flowchart for demonstrating the defect kind discrimination | determination process by the TFT array inspection apparatus of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a configuration example of a substrate on which a TFT drive circuit is formed will be described with reference to FIG. 1, a configuration of a TFT array inspection apparatus of the present invention will be described with reference to FIGS. 2 to 4, and flowcharts of FIGS. The operation of the TFT array inspection apparatus according to the present invention will be described with reference to FIGS. 6 to 9, and an example of a scanned image of the active area obtained with the TFT array inspection apparatus according to the present invention will be described.

  First, a configuration example of a substrate to be inspected by the array inspection apparatus of the present invention will be described with reference to FIG.

  In FIG. 1, a TFT drive circuit 102 for driving the TFT array in the active area 101 is formed on the substrate 100 to be inspected by the TFT array inspection apparatus 1 in addition to the active area 101 such as a panel. . A TFT array is formed in the active area 101 and the TFT drive circuit 102.

  The active area 101 can drive pixels corresponding to the TFT array by applying an inspection signal to the TFT array (not shown). Selection of the TFT array to be driven is performed by applying a signal to a gate line (not shown) via a gate circuit (not shown) of the TFT drive circuit 102. For the selected TFT array, By applying a voltage through a source line (not shown), a pixel (not shown) corresponding to the TFT array is set to a predetermined voltage.

  In the setting of the predetermined voltage, when the TFT array has a defect, the voltage of the pixel is in a voltage state different from the predetermined voltage. The voltage state that appears in the pixel due to the defect differs depending on the type of defect such as a short-circuit defect or a disconnection defect, and a voltage lower than the applied voltage may appear, or the voltage may appear in the state where no voltage is applied.

  The TFT drive circuit 102 is configured by a TFT array formed on the substrate 100 as in the active area 101. The TFT array forms, for example, a shift register including a plurality of gate circuits, and sequentially supplies gate signals to the gate lines of the active area 101.

  A plurality of active areas 101 are formed on the substrate 100, and a TFT drive circuit 102 is formed for each active area 101. The substrate 100 is provided with terminal pads 103 for inputting gate signals and scanning signals supplied to the gate lines and source lines from the outside. The terminal pad 103 and the TFT drive circuit 102 are connected by a wiring 104.

  The terminal pad 103 receives a signal from the outside by contacting a probe pin or the like provided on the prober frame, and inputs the signal to the TFT driving circuit 102 through the wiring 104.

  The configuration of the substrate 100 illustrated in FIG. 1 is an example, and is not limited to this configuration. For example, the arrangement position of the TFT drive circuit 102 and the terminal pad 103 with respect to the active area 101 is not limited to the x direction (horizontal direction in the drawing) of the active area 101 as shown in FIG. 1, but the y direction (vertical direction in the drawing). It is good.

  Next, a configuration example of the array inspection apparatus of the present invention will be described with reference to FIG. In the configuration example shown in FIG. 2, a TFT substrate such as a liquid crystal substrate is irradiated with an electron beam, secondary electrons emitted from the TFT substrate are detected, and a scanning image is formed from a detection signal of the secondary electrons. The example of a structure which performs defect detection based on this is shown. In the present invention, the substrate to be inspected is not limited to a liquid crystal substrate, and substrate scanning is not limited to an electron beam, and a charged beam such as an ion beam can be used. The detection signal depends on the charged beam to be irradiated and is not limited to secondary electrons.

  The TFT array inspection apparatus 1 includes a stage 22 on which a substrate 100 such as a liquid crystal substrate is placed and can be transported in the XY directions, and a TFT array (not shown) in an active area 101 such as a panel provided on the substrate 100. ), A prober frame 20 that applies an inspection signal, a detection unit 2 that scans the substrate 100 to acquire an image output of the active area 101, and a defect detection that detects a defect based on the image output acquired by the detection unit 2 A unit 9 and a defect type discriminating unit 10 for discriminating defect types are provided.

  The detection unit 2 is a detector that detects secondary electrons emitted from the electron gun 3 disposed above the stage 22 and away from the stage 22, and pixels (not shown) of the active area 101 of the substrate 100. 4. A plurality of sets of electron guns 3 and detectors 4 can be provided.

  The scan control unit 8 has functions of a stage drive control unit (not shown) and an electron beam scan control unit (not shown). The stage drive control unit controls the drive of the stage 22 and performs electron beam scan control. The unit controls the scanning direction of the electron beam on the substrate 100 by controlling the irradiation direction of the electron beam irradiated by the electron gun 3.

  Furthermore, the TFT array inspection apparatus 1 of the present invention includes a TFT drive circuit driver unit 7 for driving the TFT drive circuit 102 formed on the substrate 100. The TFT drive circuit driver section 7 receives the inspection signal generated by the inspection signal generation section 6 and supplies it to the TFT drive circuit 102 as a drive signal.

  The inspection signal generated by the inspection signal generation unit 6 generates a plurality of signal patterns in order to determine the type of defect in the active area. Examples of the type of defect in the active area include a short circuit defect and a disconnection defect. When the inspection signal is supplied as a drive signal to the substrate and there is a defect in the active area, a point defect site or a non-drive site of a line defect site appears in the scanned image obtained depending on the type of the defect.

  The signal processing unit 5 processes a detection signal of secondary electrons detected by the detector 4 to form a scanned image. The signal intensity and detection position of the scanned image obtained by the signal processing unit 5 are sent to the defect detection unit 9 and the defect type discrimination unit 10 to detect the defect position and determine the defect type. The defect detection unit 9 detects a non-driven part in the active area 101 based on the signal intensity of the scanned image sent from the signal processing unit 5.

  The non-driving part is a part that is not driven even when a driving signal is applied to the TFT array. For detection of non-driving parts, the signal intensity of the scanning image obtained in the normal state is set as a threshold value, and the signal intensity of the scanning image obtained when the driving signal is applied to the active area is set as this threshold value. This can be done by comparison. The magnitude relationship between the signal intensity at the time of the defect and the threshold value depends on the type of the defect, and the signal pattern of the inspection signal applied to the active area also differs depending on the defect type to be detected. Therefore, in the defect detection unit 9, the magnitude relationship between the threshold value used for defect detection and the signal intensity is set according to the defect type to be detected.

  The non-driving part that appears in the active area 101 includes a case where the TFT array in the active area 101 is not driven due to a defect and a case where the TFT drive circuit 102 is not driven due to a defect in the TFT array. Contains. A non-driving part generated due to a defect in the TFT array of the active area 101 and a non-driving part generated due to a defect in the TFT array of the TFT drive circuit 102 are formed when they appear on the active area 101. Appear differently.

  The TFT array inspection apparatus 1 of the present invention includes a defect type discriminating unit 10 that discriminates a defect type of a TFT array formed on a substrate 100 and is detected in a scanning image of an active area 101 detected by a defect detecting unit 9. Whether the defect is caused by the TFT array in the active area 101 or the TFT array in the TFT drive circuit 102 is determined based on the state in which the non-drive part appears.

  The defect type discriminating unit 10 according to the present invention has the active area 101 when the non-driving site detected in the scanned image of the active area detected by the defect detecting unit 9 appears in a region separated from each other. If the defect appears in a continuous or intermittent region, it is determined that the defect has occurred in the TFT drive circuit 102.

  When a defect occurs in the TFT array in the active area 101, it occurs independently from the other TFT arrays, and therefore appears on the active area 101 as areas separated from each other like a point defect or a line defect. The defect type discriminating unit 10 has a defect in the TFT array in the active area 101 when the non-drive parts detected in the scanning image of the active area 101 appear in areas separated from each other. Judge as.

  On the other hand, when a defect occurs in the TFT array in the TFT drive circuit 102, the drive signal applied to the active area 101 through the gate circuit where the defect has occurred on the ray shift register of the TFT drive circuit 102 is stopped. .

  In this case, the gate line region applied through the gate circuit of the defective part appears as a non-driven part, and the supply of the driving signal is also stopped for the gate circuit behind the defective part. Since the drive signal from the gate line of the circuit to the rear gate line is stopped, the entire area below the defective part is in the non-driven state, and the defect area where the line defect is intermittent or the line defect continues. A planar defect area appears.

  As described above, the defect type discriminating unit 10 is configured such that the non-driven part detected in the scanning image of the active area 101 is a defect region where a line defect is intermittent or a planar defect region where a line defect is continuous. In the case of appearing at, it is determined that a defect has occurred in the TFT array of the TFT drive circuit 102.

  In the defect type determination of the active area 101, the defect type determination unit 10 determines a point defect when the non-driven part is a point-like part when the non-driven part appears in the form of a region separated from each other. If the non-driven part is a linear part, it is determined as a line defect. Further, the defect position of the TFT array on the active area is determined from the position of the non-driven part appearing on the scanning image of the active area.

  In addition, the defect type determination unit 10 in the defect type determination of the TFT drive circuit 102, when a non-driving part has a defect region where the line defect is intermittent or a planar defect region where the line defect is continuous appears, It is determined that the TFT array of the TFT drive circuit 102 is defective, and the defect position of the TFT array on the TFT drive circuit 102 is determined from the position of the non-driven portion that appears on the scanning image of the active area. As for the defect position of the TFT array, the position of the TFT array on the TFT drive circuit 102 corresponding to the position corresponding to the head in the drive signal supply order in the region appearing on the scanning image of the active area is determined as the defect position.

  FIG. 3 is a diagram for explaining the configuration of the prober frame 20 that applies a drive signal to the substrate 100 by the TFT array inspection apparatus 1 of the present invention.

  The prober frame 20 includes probe pins 21 and is connected to the TFT drive circuit driver unit 7 through wiring. The probe pin 21 is brought into contact with the terminal pad 103 formed on the substrate 100, thereby supplying an inspection signal from the TFT drive circuit driver unit 7 to the TFT drive circuit 102 on the substrate 100 as a drive signal.

  FIG. 4 is a diagram for explaining the relationship between the TFT drive circuit 102 on the substrate 100 and the TFT drive circuit driver unit 7. The prober frame 20 shown in FIG. 3 is arranged on the substrate 100 shown in FIG. Shows the state.

  The inspection signal generated by the inspection signal generation unit 6 is sent from the TFT driver circuit driver unit 7 to the probe pin 21 through wiring arranged in the prober frame 20. The probe pins 21 are in contact with the terminal pads 103 provided on the substrate 100 and supplied to the TFT drive circuit 102 through the wiring 104. The supplied inspection signal operates as a drive signal for driving the TFT drive circuit 102, and passes through each of the TFTs through the gate line and the source line in the active area 101 via a shift register including a TFT array constituting the TFT drive circuit 102. A gate signal and a source signal are supplied to the array to drive the TFT array and to apply a predetermined voltage.

  Next, an operation example of defect detection by the TFT array inspection apparatus of the present invention will be described with reference to FIGS.

  The TFT array inspection apparatus supplies the inspection signal generated by the inspection signal generation unit 6 from the TFT drive circuit driver unit 7 to the TFT drive circuit 102 formed on the substrate 100, and the TFT drive circuit 102 causes the active area 101 to be generated. Each TFT array is driven, and the drive state is acquired as a scanned image (S1).

  The defect detection unit 9 determines the presence / absence of a defect using the scanned image acquired by the signal processing unit 5. Defect determination can be performed by comparing a scanned image with a scanned image obtained when an inspection signal is applied to a normal TFT array (S2).

  If it is determined in S2 that the defect is present, the defect type is determined. In addition to determining whether the defect is a TFT array in the active area or a TFT array in the TFT drive circuit, the defect type is determined if the defect is in the active area. Whether it is a short circuit or disconnection is determined. Whether a defect is a short circuit or disconnection can be determined by comparing it with a reference scanning image obtained when an inspection signal is applied to a normal TFT array. The one set in advance is used (S3).

  When it is determined that there is no defect in the defect determination of S2, it is determined that the active area formed on the substrate and the TFT array of the TFT drive circuit are normal. (S4).

  FIG. 6 schematically shows a scanned image when the active area and the TFT array of the TFT drive circuit are normal. In the example of the scanned image shown in the figure, it is assumed that the signal intensity in the active area is a uniform scanned image over the entire surface in a normal state. Depending on the type of scanning signal applied, the scanned image in the active area in the normal state may represent a lattice pattern.

  By comparing the pattern appearing in the scanned image obtained by detection with the scanned image obtained in the normal state, the presence / absence of a defect, defect type, defect position, etc. are determined.

  In FIG. 6, the TFT array in the active area 101 is driven by receiving a drive signal from a gate circuit of a shift register provided in the TFT drive circuit 102. The gate line of the active area 101 and the shift register of the TFT drive circuit 102 have a corresponding relationship, and each gate circuit of the shift register operates in sequence, so that a drive signal is applied to the gate line of the active area 101 in order. In the example shown in FIG. 6, the shift register of the TFT drive circuit 102 drives in order from the upper side to the lower side in the drawing, so that the drive signal is also applied to the gate line in the active area 101 from the upper side to the lower side in the drawing. Is applied, and the TFT array arranged on the gate line operates in sequence.

  FIGS. 7 to 9 show examples of scanned images when the TFT array of the active area or the TFT array of the TFT drive circuit is defective.

  FIG. 7 shows a case where the TFT array in the TFT drive circuit is defective. FIG. 7A shows an example of a scanned image when the TFT array (a in the figure) of the TFT drive circuit has a defect, and FIG. 7B shows the TFT array (b in the figure) in the TFT drive circuit. It is an example of a scanning image when there is a defect.

  7A and 7B, when the TFT array at the position a in the TFT drive circuit shift register has a defect, the gate circuit formed by the TFT array having the defect does not operate. Supply of the drive signal to the gate line of the active area 101 corresponding to this TFT array is stopped. Further, since the drive signal does not flow to the gate circuit arranged behind the defective TFT array gate circuit on the shift register, the gate line behind the gate line of the active area 101 is also applied. The drive signal supply stops.

  Therefore, in the example shown in FIG. 7A, for example, when the TFT array at the position a is defective in the shift register of the TFT drive circuit 102, the scanning image of the active area 101 includes the TFT array at the position a. The non-driving part which consists of the area | region A intermittent from the position La on the active area corresponding to to appears.

  Further, in the example shown in FIG. 7B, for example, when the TFT array at the position b is defective in the shift register of the TFT drive circuit 102, the scanned image of the active area 101 includes the TFT array at the position b. A non-driving part consisting of a continuous region B appears downward from the corresponding position Lb on the active area.

  Therefore, when an intermittent or continuous non-drive portion as shown in the region A or the region B appears in the scanned image of the active area 101, it is determined that the TFT array on the TFT drive circuit 102 is defective. In each region, it can be determined that the TFT array on the TFT drive circuit 102 corresponding to the head in the drive direction is defective.

  FIG. 8 shows a case where the TFT array in the active area is defective. FIG. 8A shows an example of a scanned image when a TFT array in the active area (position c and position d in the figure) has a defect, and FIG. 8B shows a TFT array in the active area (position e in the figure). , Position f) is an example of a scanned image when there is a defect.

  In FIG. 8A, when the TFT array at the positions c and d in the TFT array in the active area has a defect, the TFT array having the defect does not operate. Line defects C and D appear. Whether a line defect C or a line defect D appears depends on the type of defect in the TFT array and the pattern of the scanning signal to be applied.

  In FIG. 8B, when the TFT array at the position e and position f in the TFT array in the active area has a defect, the TFT array having this defect does not operate, so the scanned image of the active area 101 is scanned. Point defects E and F appear.

  Whether a line defect or a point defect appears, and whether the line defect is a vertical line defect but a horizontal line defect depends on the type of defect in the TFT array and the pattern of the scanning signal to be applied. To do.

  FIG. 9 shows an example of a scanned image obtained when a defect exists in both the TFT drive circuit 102 and the active area 101 TFT array.

  FIG. 9 shows an example of a scanned image obtained when the TFT array at position a is defective in the TFT drive circuit 102 and the TFT array at positions e and f is defective in the active area 101. In the scanned image, an intermittent line is shown. A defect area A and point defects E and F appear.

  Here, since the drive signals are first supplied to the TFT drive circuit 102 and then supplied to the active area 101, if there is a defect in the TFT array of the TFT drive circuit 102, the defect is detected from the TFT array having the defect. Since no driving signal is supplied to the TFT array of the shift register located behind, the region A appears as a non-driven portion regardless of whether the TFT array on the active area in the region A is normal or defective. Therefore, even if a point defect or a line defect exists in the active area in the area A, it does not appear in the scanned image. Therefore, in the scanned image on the active area, the defect of the TFT array of the TFT drive circuit appears in preference to the defect of the TFT array of the active area.

  Next, with reference to FIG. 10, an operation example for determining the defect type by the TFT array inspection apparatus of the present invention will be described.

  When a non-driven part is detected from the scanned image, it is determined from the form of the non-driven part whether it is a point defect part, a line defect part, or a defective part of the region. This form determination of the non-driven part is performed by, for example, forming a defect data string determined as a defect by comparing the signal intensity of the scanned image with the signal intensity of the scanned image obtained at normal time, and the continuity of the data string, etc. This can be done by determining.

  For example, when the number of continuous data strings is equal to or less than a predetermined number, it is determined as a point defect or a line defect, and when a continuous data string appears intermittently or continuously, it is determined as a region defect. The number of data and the number of data strings used for determination can be set in advance according to the type of defect to be formed (S31).

  In the determination of S31, if the form of the non-driven part is a point defect or a line defect, it is determined that there is a defective part in the active area (S32). The cause of the defect can be determined. The defect factor is determined according to the scanning pattern to be applied (S33).

  In the determination of S31, when the form of the non-driving part is a region part, it is determined that there is a defective part in the TFT drive circuit (S34).

  In the determination of S31, if the form of the non-driving portion includes a point defect or a line defect and also a region portion, it is determined that both the active area and the TFT driving circuit have a defective portion (S35). If there is a further need, the cause of the defect can be determined in the case of a point defect or a line defect as in S33 (S36).

  In the present invention, the TFT substrate can be a liquid crystal substrate or an organic EL, and can be applied to a film forming apparatus for forming various semiconductor substrates in addition to a film forming apparatus for forming a liquid crystal substrate or an organic EL.

DESCRIPTION OF SYMBOLS 1 Array inspection apparatus 2 Detection part 3 Electron gun 4 Detector 5 Signal processing part 6 Inspection signal generation part 7 Driver circuit driver part 8 Scan control part 9 Defect detection part 10 Defect detection part 20 Prober frame 21 Probe pin 22 Stage 100 Substrate 101 Active area 102 TFT drive circuit 103 Terminal pad 104 Wiring a, b, c, d, e, f Position A, B area C, D Line defect E, F Point defect

Claims (7)

In a TFT array inspection apparatus for inspecting a TFT array formed on a substrate,
The substrate includes an active area and a TFT drive circuit that drives the active area, and both are formed of a TFT array.
The TFT array inspection apparatus includes a TFT drive circuit driver unit that supplies an inspection signal to the TFT drive circuit,
Scanning the active area, and based on a scan image of the active area obtained by the scanning, a TFT drive circuit and a detection unit for detecting the drive state of the active area,
The TFT drive circuit driver unit drives the TFT array of the TFT drive circuit by supplying an inspection signal to the TFT drive circuit, and the TFT formed in the active area by driving the TFT array of the TFT drive circuit Drive the array,
The detection unit detects a non-driving part in the scanning image of the active area, and detects a non-driving state of the active area and a non-driving state of the TFT driving circuit based on the appearance state of the non-driving part. A TFT array inspection apparatus characterized by the above.   In the detection of the non-driving state of the active area and the non-driving state of the TFT driving circuit, the detection unit detects the non-driving state of the TFT driving circuit in preference to the non-driving state of the active area. The TFT array inspection apparatus according to claim 1. The TFT drive circuit includes a gate circuit configured by a shift register formed by a TFT array,
3. The TFT drive circuit driver unit sequentially drives the gate circuit of the shift register, and sequentially drives the active area according to the drive order of the shift register. TFT array inspection device. Provided with a defect type discriminating unit for discriminating the defect type of the TFT array formed on the substrate,
The defect type discriminating unit discriminates whether the defect is an active area defect or a TFT driving circuit defect based on a form in which a non-driving part detected in the scanning image of the active area detected by the detecting unit appears. The TFT array inspection apparatus according to any one of claims 1 to 3.   The defect type discriminating unit determines that the defect appears in the active area when the form in which the non-driving site detected in the scanned image of the active area detected by the detection unit appears in areas separated from each other. The TFT array inspection apparatus according to claim 4, wherein if it is a form that appears in a continuous or intermittent region, it is determined that the TFT drive circuit is defective.   In the defect type discrimination of the active area, the defect type discrimination unit is a form in which the non-driven sites appear in areas separated from each other, and determines that the non-driven site is a point defect when the non-driven site is a point-like site, 6. The TFT array inspection according to claim 5, wherein when the non-driven part is a linear part, it is determined as a line defect, and the position of the part is determined as a defect position of the TFT array on the active area. apparatus.   In the defect type determination unit of the TFT drive circuit, the non-drive part that appears in a continuous area is a planar area, or the non-drive part that appears in an intermittent area is intermittently a linear part. In the case of the appearing region, the position on the TFT driving circuit corresponding to the head in the driving order of the TFT driving circuit for driving the region in the region on the active area is defined as the defect position of the TFT array of the TFT driving circuit. The TFT array inspection apparatus according to claim 5, wherein determination is performed.