JP5459491B2 - TFT array inspection apparatus and TFT array inspection method - Google Patents

Description

  The present invention relates to a TFT array inspection for inspecting an array of a TFT substrate such as a liquid crystal substrate, and more particularly to data processing with a detection intensity suitable for defect detection of a TFT array.

  In a liquid crystal array inspection apparatus, as a picked-up image obtained by picking up an image on a liquid crystal substrate, an optical pick-up image obtained by optical pick-up or a charged particle beam such as an electron beam or an ion beam is two-dimensionally displayed on the substrate. A scanned image obtained by scanning can be used.

  In the manufacturing process of the TFT array substrate used in the TFT display device, an inspection is performed to check whether the manufactured TFT array substrate is driven correctly (Patent Documents 1 and 2).

  For example, an inspection signal is applied to an array of substrates to be inspected to bring the array into a predetermined potential state, and the substrate is scanned by two-dimensional irradiation with a charged particle beam such as an electron beam or an ion beam. There is known an array inspection apparatus for inspecting an array of TFTs based on a scanning image obtained in (1). In the TFT array inspection, secondary electrons emitted by electron beam irradiation are detected by converting them into analog signals using a photomultiplier or the like, and an array defect is determined based on the signal intensity of the detection signals.

  The array and the pixel of the TFT substrate are formed correspondingly, and a specific pixel can be driven by applying a drive signal to the array. In TFT array inspection, generally, a drive signal of a predetermined pattern is applied to the array to drive each pixel of the panel formed in the substrate with a predetermined pattern, and these pixels are irradiated with an electron beam and emitted from the irradiation point. Secondary electrons detected. A detection signal is acquired from each pixel in the panel by performing this electron beam irradiation in the panel.

JP 2004-271516 A JP 2004-309488 A

  When scanning by irradiating an electron beam on a panel formed on a substrate, the scanning width (scanning width) when scanning the electron beam with respect to the panel is usually fixed to a constant width. This scan width determines the width of the detection range in which defect detection is performed in the panel. On the other hand, in the panel formed on the substrate, the panel size and the size of the pixel formed on each panel differ depending on the specifications of the panel and the pixel.

  Since the arrangement length Lp of the pixels in the scanning direction is approximately determined by a multiple of the width (pixel width) Wp of the pixels in the scanning direction, the arrangement length of the pixels arranged in the scanning direction depends on the pixel size of the panel to be inspected. There are cases where the scanning width of the electron beam does not match.

  FIG. 11 is a diagram for explaining the relationship between the scanning width Ws and the pixel arrangement length Lp, and FIG. 11A shows a case where the scanning width Ws and the pixel arrangement length Lp match. FIG. 11B shows a case where the scanning width Ws does not match the pixel arrangement length Lp.

  As shown in FIG. 11A, when the scanning width Ws matches the pixel arrangement length Lp, the width Wd of the detection range in which defect detection is performed matches the pixel arrangement length Lp. A signal required for defect detection can be acquired for all pixels arranged in the scanning width Ws. On the other hand, as shown in FIG. 11B, when the scanning width Ws and the pixel array length Lp do not match, the width Wd of the detection range in which defect detection is performed and the pixel array length Lp match. In other words, the pixels at both ends of the panel are displaced from the ends of the scanning width Ws, and a signal required for defect detection may not be acquired.

  Thus, when a signal required for defect detection cannot be acquired, there is a problem that a normal pixel is erroneously detected as a defective pixel, and the defect detection accuracy is lowered.

  When a signal for detecting a defect of a panel formed on a substrate is acquired by scanning, the scanning range is not covered by one scanning because the scanning width is limited. Therefore, a method is adopted in which the scanning range is divided into a plurality of scanning ranges in a strip shape with respect to the scanning direction, and scanning is performed while sequentially shifting each scanning range by moving the stage on which the substrate is placed. In addition, a plurality of electron guns are arranged in the scanning direction, and signals in a wide scanning range are acquired by combining signals obtained by scanning with each electron gun.

  FIG. 12 is a diagram for explaining the above-described scanning mode. The electron guns G1 and G2 scan the four scanning ranges of the pass P1 to the pass P4, respectively, thereby detecting panel defects in a wide scanning range. Detect the signal to be performed.

  The location where the problem of erroneous detection of defects due to the constant scanning width occurs is particularly likely to occur at the boundary portion of the adjacent path or the boundary portion of the adjacent electron gun.

  Therefore, the present invention aims to solve the above-mentioned problems, solve the problem of erroneous detection of defects caused by a constant scanning width, reduce the erroneous detection of defects, and improve the detection accuracy of defects. And

  According to the present invention, in a signal image of a scanning range acquired with a constant scanning width, defect detection is performed using only the signal image of the central portion, excluding the signal images of both end portions in the scanning direction, and thereby the scanning range and the pixels This solves the problem that a signal required for defect detection cannot be obtained due to the position shift, reduces false detection of defects, and improves defect detection accuracy.

  In addition, if only the signal image at the center part is used except the signal images at both ends in the scanning direction, the signal images at both ends in the scanning direction are not used for defect detection. It becomes a detection range, and defect detection cannot be performed for this part.

  Therefore, the present invention supplements the signal image in the undetected range in one scanning range with the signal image in the detected range in the other scanning range by scanning the adjacent portions in the adjacent scanning range overlapping each other. This prevents an undetected range from occurring in the scanning range of each other.

  This invention can be made into two aspects, the aspect of a TFT array inspection method, and the aspect of a TFT array inspection apparatus.

  In the TFT array inspection method of the present invention, an array is driven by applying an inspection signal of a predetermined voltage to a panel of a TFT substrate, and an electron beam is irradiated on pixels corresponding to the array on the panel. This is a TFT substrate array inspection method for detecting emitted secondary electrons and inspecting an array of TFT substrates based on a detection signal of the detected secondary electrons.

  The electron beam scans the scanning range on the TFT substrate with a constant scanning width regardless of the pixel size. A signal image in the scanning range is formed by a detection signal acquired by scanning with an electron beam, and the formed signal image is divided into a detection range in which pixel defect detection is performed and a non-detection range in which pixel defect detection is not performed.

  The non-detection range is both end portions in the scanning direction of the electron beam in the signal image obtained within the scanning range. The width of each end portion in the scanning direction can be determined according to the pixel size, and the signal image acquired in this non-detection range is not used as defect detection data.

  On the other hand, in the signal image acquired in the scanning range, a portion excluding the non-detection range is set as a detection range, and pixel defect detection is performed based on the signal intensity of the signal image in the detection range. An array corresponding to the defective pixel detected by this defect detection is detected as a defective array.

  While the scanning width is a fixed and fixed width, the arrangement length obtained by arranging the pixels in the scanning direction varies depending on the width of the pixels in the scanning direction.

  Here, the number of pixels is set so that the width in the scanning direction of the detection range used for defect detection is within the scanning width, and the amount of positional deviation at one end of the pixel array length and the scanning width is shorter than the width of the pixel in the scanning direction. Set. In this setting, if the width in the scanning direction of the non-detection range is set to the width in the scanning direction of the pixel, the amount of positional deviation between the scanning range and the pixel is within the width in the scanning direction of the pixel. The problem that the signal required for defect detection cannot be acquired due to the displacement can be solved, and the detection range can be effectively utilized with the deletion amount of the image signal due to the non-detection range being minimized.

  When the width of the non-detection range in the scanning direction is set to be greater than or equal to the width of the pixel in the scanning direction, the amount of positional deviation between the scanning range and the pixel can be accommodated within the width of the pixel in the scanning direction with a margin. Since the detection range is narrowed by increasing the non-detection range, the amount effectively used as the detection range is reduced.

  As described above, when only the signal image at the center part is used as the detection range except the signal image at both end parts in the scanning direction, the signal image at both end parts in the scanning direction becomes an undetected range, and defect detection of this part is detected. Can not do.

  Therefore, in the adjacent scanning range, the adjacent portions are scanned in an overlapping manner, and the signal image of the undetected range of one scanning range is supplemented with the signal image of the detected range in the other scanning range. An undetected range is prevented from occurring in the scanning range.

  In order to perform overlapping scanning, the scanning range is set so that overlapping ranges are formed in a plurality of scanning ranges adjacent in the scanning direction. When scanning each scanning range, by scanning the overlapping range, at least the non-detection range of the adjacent scanning range is scanned. In the adjacent scanning range, the signal image of one detection range in the overlapping range obtained by the overlapping scanning is set as the signal image of the other adjacent non-detection range. As a result, the non-detection range in each scanning range is supplemented by the detection range of the adjacent scanning range, so that the undetected range can be excluded from the scanning range.

  In the TFT array inspection apparatus according to the present invention, an array is driven by applying an inspection signal of a predetermined voltage to the panel of the TFT substrate, and an electron beam is irradiated on the pixel corresponding to the array on the panel. This is a TFT substrate array inspection apparatus that detects secondary electrons emitted by the, and inspects an array of TFT substrates based on a detection signal of the detected secondary electrons.

  The TFT substrate array inspection apparatus includes: an electron beam scanning control unit that scans an electron beam on the TFT substrate; a signal processing unit that calculates a signal intensity for determining a defect of the TFT substrate array based on the detection signal; A defect determination unit that performs array defect determination based on the signal intensity obtained by the processing unit.

  The electron beam scanning control unit scans a scanning range having a constant scanning width regardless of the pixel size.

  The signal processing unit forms a signal image in the scanning range from the detection signal acquired by scanning the electron beam, and divides the signal image into a detection range where pixel defect detection is performed and a non-detection range where pixel defect detection is not performed To do. The non-detection range is the both ends of the scanning direction of the electron beam in the signal image, and the width in the scanning direction of each portion of both ends is determined according to the pixel size.

  The defect determination unit performs pixel defect detection based on the signal intensity of the signal image in the detection range, and detects an array corresponding to the defective pixel detected by the defect detection as a defect array. The width of the non-detection range in the scanning direction can be the width of the pixel in the scanning direction.

  By setting the signal image of the both ends in the scanning direction to the undetected range, it is possible to prevent the acquisition of the signal required for defect detection due to the displacement of the scanning range and the pixel, but the defect detection of this part is performed There is a problem that can not be.

  In order to solve this problem, in a plurality of scanning ranges adjacent in the scanning direction as scanning ranges, two adjacent scanning ranges are set to have overlapping ranges that overlap each other.

  In the scanning of each scanning range, the electron beam scanning control unit scans at least the non-detection range of the adjacent scanning range by scanning the overlapping range. A signal processing part makes the signal image of one detection range in an overlapping range mutually the signal image of the other adjacent non-detection range.

  ADVANTAGE OF THE INVENTION According to this invention, the problem of the erroneous detection of a defect resulting from a scanning width being constant can be solved, the erroneous detection of a defect can be reduced, and the detection accuracy of a defect can be improved.

  According to the present invention, an overlapping range that overlaps two adjacent scanning ranges is provided, and a signal image in one detection range in the overlapping range is used as a signal image in the other non-detection range. By providing the non-detection range in the range, it is possible to solve the problem that a range in which the defect cannot be detected occurs.

It is a schematic block diagram for demonstrating the structural example of the TFT array test | inspection apparatus of this invention. It is a figure for demonstrating the non-detection range of the TFT array test | inspection of this invention. It is a figure for demonstrating the non-detection range and overlapping range of the TFT array test | inspection of this invention. It is a figure for demonstrating the duplication range by the TFT array test | inspection of this invention. It is a figure for demonstrating the duplication range by the TFT array test | inspection of this invention. It is a figure for demonstrating the duplication range by the TFT array test | inspection of this invention. It is the schematic for demonstrating the structure of the TFT array test | inspection apparatus of this invention. It is a figure of the structural example for demonstrating the outline of the operation | movement by the TFT array test | inspection apparatus of this invention. It is a flowchart for demonstrating the outline of the operation | movement by the TFT array test | inspection apparatus of this invention. It is a figure for demonstrating the outline of the operation | movement by the TFT array test | inspection apparatus of this invention. It is a figure for demonstrating the relationship between the scanning width Ws and the arrangement length Lp of a pixel. It is a figure for demonstrating the form of a scan.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, the non-detection range by the TFT array inspection of the present invention will be described with reference to FIGS. 1 and 2, and the non-detection range and the overlapping range by the TFT array inspection of the present invention will be described by using FIG. The overlapping range by the TFT array inspection of the present invention will be described using FIG. 7, the configuration of the TFT array inspection apparatus of the present invention will be described using FIG. 7, and the embodiment of the TFT array inspection will be described using FIGS. .

  First, the non-detection range of the TFT array inspection of the present invention will be described with reference to FIGS.

  FIG. 1 shows one panel 20 among a plurality of panels formed on a TFT substrate. Pixels formed on the panel by irradiating the electron gun and moving the electron beam in the scanning direction (lateral direction in the figure) with respect to the panel 20 and detecting secondary electrons emitted by the electron beam irradiation. Detect defects.

  The panel 20 is irradiated with an electron beam while moving in the x direction (horizontal direction in the figure) and the y direction (horizontal direction in the figure), and secondary electrons emitted from each pixel formed on the panel are irradiated. By detecting, a detection signal is detected for the scanning range 21 on the panel surface. The detection signal of the scanning range 21 can be acquired as an image signal.

  The movement of the electron beam in the x direction and the y direction with respect to the panel is performed by shaking the electron beam irradiated from the electron gun in the x and y directions with an electromagnetic coil or the like. It can also be performed by moving the stage to be placed.

  Here, the scanning direction of the panel 20 is scanned by combining the x direction with respect to the panel 20 as the scanning direction and combining the folding at both ends of the panel and the movement in the y direction in this scanning direction.

FIG. 1 shows a part of the panel. As shown in FIG. 12 , the entire surface of the panel is divided and scanned by a plurality of electron guns, and the range scanned by each electron gun is further divided into a plurality of paths. This is an example of scanning as a unit, and shows a scanning range 21 by one pass.

  In FIG. 1, the width of the scanning range 21 in the scanning direction (x direction) is defined as a scanning width Ws. The scanning width Ws is set by an irradiation mechanism that irradiates an electron beam, and is fixed at a constant regardless of the specification (size) of the panel or pixel of the inspection target substrate.

  When the width in the scanning direction of the pixels 30 formed on the panel 20 of the inspection target substrate is Wp, the length in the scanning direction of the pixels arranged corresponding to the scanning range 21 (pixel arrangement length) Lp is Wp. It depends on.

  As described in the section of the problem to be solved by the invention, the pixel array length Lp does not necessarily coincide with the scanning width Ws, and the detection signals of the pixels at both ends of the scanning range 21 are not effective for defect detection. May be appropriate.

  In the present invention, the signal image of the scanning range 21 is divided into a detection range 22 and a non-detection range 23, and the signal image of the non-detection range 23 is not used for defect detection, but only the signal image of the detection range 22 is used for defect detection. By doing so, problems at both ends of the scanning range 21 are eliminated.

  The non-detection range 23 is an end portion of the scanning range 21 and is a range having a predetermined width Wnd in the scanning direction. The predetermined width Wnd can be determined based on the width Wp of the pixel 30 in the scanning direction. For example, the predetermined width Wnd can be set to the width Wp of the pixel 30 in the scanning direction. In FIG. 1, the non-detection range 23 is shown with a ground pattern.

  On the other hand, the detection range 22 is a portion obtained by removing the non-detection range 23 from the scanning range 21, and is a range on the center side of the scanning range 21. Accordingly, the width Wd of the detection range 22 is a value represented by (Ws−2Wnd) obtained by subtracting the width Wnd of the non-detection ranges 23 on both sides from the width Ws of the scanning range.

  FIG. 2 shows a non-detection range 23 provided at both ends of the scanning range 21 and shows an example in which there is a positional deviation between the pixel array end and the scanning range.

  In FIG. 2, a rectangle indicates a pixel, a circle in the rectangle indicates an irradiation point of an electron beam, a circle in a broken line indicates an irradiation point corresponding to an image signal within the non-detection range, and a × mark indicates defect detection. A pixel that is not provided is shown, a vertical broken line indicates an end of the scanning range 21, and a thick vertical solid line indicates a boundary between the detection range 22 and the non-detection range 23.

  As shown in FIG. 2, the scanning range 21 is divided into a detection range 22 and a non-detection range 23, and a signal image obtained by a detection signal in the non-detection range 23 is not used for defect detection, but in the detection range 22. Defect detection is performed using only the signal image obtained from the detection signal. As a result, as shown in FIG. 2, even when the end of the pixel array does not coincide with the end of the scanning range 21, the shift in the correspondence between the signal image and the pixel caused by this positional shift is used for defect detection. The influence which it has can be prevented.

  Next, the non-detection range and the overlapping range will be described with reference to FIG. As described above, the scanning range is divided into the detection range and the non-detection range, and the signal image obtained by the detection signal in the detection range is not used for the defect detection for the signal image obtained by the detection signal in the non-detection range. By using only the defect detection, it is possible to prevent the influence on the defect detection due to a shift in the correspondence between the signal image and the pixel, but the signal image cannot be obtained in the non-detection range. If there is a defect in a pixel within the detection range, defect detection cannot be performed.

  Therefore, in the plurality of scanning ranges adjacent in the scanning direction, overlapping ranges are provided in two adjacent scanning ranges, and at least the non-detection range of the adjacent scanning ranges is determined by scanning the overlapping range in the scanning of each scanning range. By scanning, the signal image of one detection range in the overlapping range is made the signal image of the other non-detection range adjacent to each other, thereby complementing the signal image of the non-detection range, thereby enabling defect detection for the entire scanning range And

  FIG. 3 shows an example in which the scanning range of one electron gun is divided into four, each divided portion is set as one pass, and the positional relationship between the electron gun and the panel is moved in the scanning direction to scan four passes. Yes. The width of each pass in the scanning direction is set corresponding to the scanning width Ws. The number of passes is not limited to 4 passes.

  In the scanning of each pass, an overlapping range 24 that overlaps each other is provided in the adjacent scanning range. In FIG. 3, an example in which an overlapping range 24a is provided between the path P1 and the path P2, an overlapping range 24b is provided between the path P2 and the path P3, and an overlapping range 24c is provided between the path P3 and the path P4. Show.

  The signal image of the path P1 is overlapped on the path P2 side in the overlapping range 24a between the signal image of the detection range 22 obtained by removing the non-detection range 23 from the scanning range 21 of the path P1 and the adjacent path P2. It can be obtained by combining with a signal image of a range.

  The signal image of the path P2 is an overlap on the path P1 side in the overlapping range 24a between the signal image of the detection range 22 obtained by removing the non-detection range 23 from the scanning range 21 of the path P2 and the adjacent path P1. This can be obtained by combining the signal image in the range and the signal image in the overlapping range on the path P3 side in the overlapping range 24b between the adjacent paths P3.

  The signal image of the path P3 is overlapped on the path P2 side in the overlapping range 24b between the signal image of the detection range 22 obtained by removing the non-detection range 23 from the scanning range 21 of the path P3 and the adjacent path P2. This can be obtained by combining the signal image in the range and the signal image in the overlapping range on the path P4 side in the overlapping range 24c between the adjacent paths P4.

  The signal image of the path P4 is overlapped on the path P3 side in the overlapping range 24c between the signal image of the detection range 22 obtained by removing the non-detection range 23 from the scanning range 21 of the path P4 and the adjacent path P3. It can be obtained by combining with a signal image of a range.

  Further, when scanning is performed with a plurality of electron guns, a signal image lacks due to not using an image signal in the non-detection range even at the boundary between the electron guns. Also in this case, by providing overlapping ranges that overlap each other in the scanning range of adjacent electron guns, similarly, a signal image that compensates for the non-detection range can be acquired from the adjacent overlapping range.

  In the signal image of the path P1, since the adjacent path is only the path P2, and there is no adjacent path at the other end, a signal image that compensates for the non-detection range cannot be obtained from the adjacent overlapping range. In this case, a signal image is acquired by scanning the end portion.

  The overlapping range by the TFT array inspection of the present invention will be described with reference to FIGS. 4A to 4C show a case where one pixel corresponds to the non-detection range, and FIGS. 4D to 4F show a case where two pixels correspond to the non-detection range. Show.

  4A and 4D show the right end of the left pass in the scanning direction in two adjacent passes, and FIGS. 4B and 4E show the left end of the right pass in the scanning direction in the two adjacent passes. Shows the part. Here, the overlapping range is set so as to include each non-detection range.

  The detection range 22L in FIG. 4A is a range obtained by excluding the non-detection range 23L from the scanning range 21L. When defect detection is performed using the detection range 22L, the image signal of the non-detection range 23L is lacking. On the other hand, the detection range 22R in FIG. 4B is a range obtained by excluding the non-detection range 23R from the scanning range 21R. If defect detection is performed using the detection range 22R, the signal image of the non-detection range 23R is lacking. . Here, four signal images within one pixel are lacking.

  In order to compensate for the lack of signal images in the non-detection ranges 23L and 23R, image signals in the overlapping range 24 (24R and 24L) are used. FIG. 4C shows an example in which the signal image in the non-detection range 23 is supplemented with the signal image in the overlap range 24.

  The detection range 22L compensates for the lack of the signal image of the non-detection range 23L by the overlapping range 24R on the adjacent scanning range 21R side, and the detection range 22R is the signal range of the non-detection range 23R by the overlapping range 24L on the adjacent scanning range 21L side. Make up for the lack.

  4A to 4C, four signal images in one pixel in the non-detection range are supplemented from the signal images in the overlapping range.

  The detection range 22L in FIG. 4D is a range obtained by excluding the non-detection range 23L from the scanning range 21, and when defect detection is performed using the detection range 22L, the image signal of the non-detection range 23L is lacking. On the other hand, the detection range 22R in FIG. 4E is a range obtained by excluding the non-detection range 23R from the scanning range 21, and if defect detection is performed using the detection range 22R, the signal image of the non-detection range 23R is missing. . Here, two signal images within one pixel are lacking.

  In order to compensate for the lack of the signal images 23L and 23R in the non-detection range, the image signals in the overlapping range 24 (24R and 24L) are used. FIG. 4F shows an example in which the signal image in the non-detection range 23 is supplemented by the signal image in the overlap range 24.

  The detection range 22L compensates for the lack of the signal image of the non-detection range 23L by the overlapping range 24R on the adjacent scanning range 21R side, and the detection range 22R is the signal range of the non-detection range 23R by the overlapping range 24L on the adjacent scanning range 21L side. Make up for the lack.

  4D to 4F, the signal images at two points in one pixel in the non-detection range are supplemented from the signal images in the overlapping range.

  The overlapping range can be provided at the boundary of the scanning range scanned by the adjacent path and the boundary of the scanning range scanned by the adjacent electron gun.

  FIG. 5 shows an example in which the overlapping range is provided at the boundary of the scanning range scanned by the adjacent path. As shown in FIG. 5A, at the boundary between the pass P1 and the pass P2, an overlapping range is provided in which the scanning range of the pass P1 and the scanning range of the pass P2 overlap each other. In this overlapping range, the scanning ranges of adjacent paths each include a non-detection range and a detection range, and the other path side has a detection range corresponding to the non-detection range with respect to the non-detection range of one path. ing.

  In FIG. 5B, the detection range is A in the scanning range of pass P1, the non-detection range and the detection range in the overlapping range are a1 and a2, respectively, and the detection range is B in the scanning range of pass P2. If the non-detection range and the detection range in the overlapping range are expressed as b1 and b2, respectively, the image signal of the path P1 can be formed by the signal image of the detection range A and the signal image of the detection range b2 of the path P2. The image signal of P2 can be formed by the signal image of the detection range B and the signal image of the detection range a2 of the path P1.

  FIG. 6 shows an example in which the overlapping range is provided at the boundary of the scanning range scanned by the adjacent electron gun. As shown in FIG. 6 (a), at the boundary between the electron gun G1 and the electron gun G2, the overlapping scanning is performed so that the scanning range of the path P4 by the electron gun 1 and the scanning range of the path P1 by the electron gun 2 overlap each other. Set a range. In this overlapping range, the scanning range of the path by the adjacent electron gun includes a non-detection range and a detection range, respectively, and the non-detection range of the path by the other electron gun is non-detection with respect to the non-detection range of the path by one electron gun. It has a detection range corresponding to the range.

  In the scanning range of the path P4 by the electron gun G1, the detection range is D, the non-detection range and the detection range in the overlapping range are d1 and d2, respectively, and the detection range is A in the scanning range of the path P1 by the electron gun G2. When the non-detection range and the detection range in the overlapping range are expressed as a1 and a2, respectively, the image signal of the path P4 of the electron gun G1 is the signal image of the detection range D and the signal image of the detection range a2 of the path P1 of the electron gun G2. The image signal of the path P1 of the electron gun G2 can be formed by the signal image of the detection range A and the signal image of the detection range d2 of the path P4 of the electron gun G1.

[Configuration of TFT array inspection equipment]
FIG. 7 is a schematic view for explaining the configuration of the TFT array inspection apparatus of the present invention.

  FIG. 7 is a schematic block diagram for explaining a configuration example of the TFT array inspection apparatus of the present invention. In the example shown in FIG. 7, a TFT substrate such as a liquid crystal substrate is irradiated with an electron beam, secondary electrons emitted from the TFT substrate are detected, a signal image is formed from a detection signal of the secondary electrons, and the signal image is formed on the signal image. The example of a structure which performs defect detection based on this is shown.

  In FIG. 7, a TFT array inspection apparatus 1 includes a stage 2 on which a TFT substrate 100 such as a liquid crystal substrate is placed and can be conveyed in the X and Y directions, and an electron gun G3 disposed above the stage 2 and away from the stage 2. And a detector 4 for detecting secondary electrons emitted from a pixel (not shown) of the panel 101 of the TFT substrate 100. The figure shows a configuration example in which a plurality of electron guns and a plurality of detectors are arranged in the scanning direction.

  The stage drive control unit 6 controls driving of the stage 2, and the electron beam scanning control unit 5 controls the scanning direction of the electron beam on the TFT substrate 100 by controlling the irradiation direction of the electron beam irradiated by the electron gun 3. The signal processing unit 10 detects the detection signal of the secondary electrons detected by the detector 4 to form a signal image, and sends the signal intensity and detection position of the obtained signal image to the defect detection unit 11. The defect detection unit 11 detects a pixel defect based on the signal intensity of the signal image sent from the signal processing unit 10, and detects a defective pixel and a corresponding defect array based on the detection position.

  Since the pixels and the array are formed on the panel of the TFT substrate and each pixel is driven by applying a voltage to the array, the pixel defect detection corresponds to the array inspection for the pixel.

  The drive operation of each part of the electron beam scanning control unit 5, the stage drive control unit 6, the signal processing unit 10, and the defect detection unit 11 is controlled by the control unit 7. The control unit 7 has a function of performing control including the entire operation of the TFT array inspection apparatus 1, and can be configured by a CPU that performs these controls and a memory that stores a program that controls the CPU.

  The stage 2 mounts the TFT substrate 100 and is movable in the X-axis direction and the Y-axis direction by the stage drive control unit 6, and the electron beam irradiated from the electron gun G 3 is an electron beam scanning control unit 5. Can be swung in the X-axis direction or the Y-axis direction. The stage drive control unit 6 and the electron beam scanning control unit 5 can scan the electron beam on the TFT substrate 100 and irradiate each pixel on the panel 101 of the TFT substrate 100 by single or cooperative operation.

[Operation example of TFT array inspection device]
8 to 10 are a configuration example, a flowchart and an explanatory diagram for explaining the outline of the operation of the TFT array inspection apparatus of the present invention.

  FIG. 8 is a block diagram of a configuration example of the signal processing unit 10 of the TFT array inspection apparatus shown in FIG. Each block shown here represents each element of signal processing, and each processing can be configured by hardware or software. Further, in the case of configuring with hardware, it is not always necessary to provide hardware corresponding to the illustrated components. In the configuration by software, for example, it can be configured by a CPU and a memory for storing processing data and processing data for causing the CPU to execute processing operations.

  In FIG. 8, a signal processing unit 10 receives a detection signal from a detector to form a signal image, a signal image forming unit 10a, a storage unit 10b that stores a signal image formed by the signal image forming unit 10a, and a storage unit 10b. A readout unit 10c that reads out a signal image from the unit, a coupling unit 10d that couples the readout signal image, a pixel detection unit 10e that detects a lit pixel using the signal image of the panel coupled by the coupling unit 10d, and the coordinate position of the detected pixel A pixel coordinate calculation unit 10f for calculating and a pixel intensity calculation unit 10g for calculating the intensity of the detected pixel are provided.

  The storage unit 10b stores a signal image obtained by scanning each path in scanning with each electron gun. In the storage unit 10b, for example, a signal image is stored for each detector path. The signal image of each panel has an overlapping range that overlaps with an adjacent path in order to compensate for a lack of detection signal caused by a shift in pixel array length and scanning width.

  The combining unit 10d reads the signal images of the electron guns and the panels from the storage unit 10b and combines them to form a signal image of the entire panel. At this time, the signal image corresponding to the non-detection range in each signal image is supplemented by the corresponding portion of the signal image from the overlapping range of adjacent paths.

  The pixel detection unit 10e detects a lighting pixel or a non-lighting pixel that is in a lighting state in the panel, based on the signal image of the entire panel obtained by combining by the combining unit 10d. Here, the pixel is lit according to the drive pattern of the drive signal applied to the array. This drive pattern is a predetermined pattern for driving pixels in order to identify the defect type of the array. For example, the pixels are driven in a striped pattern or a grid pattern in the scanning direction or a direction orthogonal to the scanning direction. The pixels in the normal array are turned on according to the applied drive pattern, and the pixels in the defective array are turned on or off in a pattern different from the applied drive pattern. By detecting the lit or unlit state of this pixel, defective pixels and defective arrays can be detected.

  The pixel intensity calculation unit 10g calculates the pixel intensity based on the pixel detected by the pixel detection unit 10e. Since the intensity of a lit or non-lit pixel varies even in a normal state, it is not possible to detect the normality or defect of a pixel only by the presence or absence of lighting, so compare with a predetermined threshold value. The normality and defect of the pixel are detected. The pixel intensity calculation unit 10g calculates pixel intensity for this comparison process.

  In the flowchart of FIG. 9, first, the scanning width Ws and the pixel width Wp are acquired. Here, the scanning width Ws is a fixed constant value, and the pixel width Wp is a value determined according to the specifications of the substrate and panel to be inspected (S1).

  Based on the acquired scanning width Ws and pixel width Wp, the width Wd of the detection range and the width Wnd of the non-detection range of one panel are calculated and set. The width Wd of the detection range is, for example, a length that is an integral multiple of the pixel width Wp, and may be shorter than the scanning width Ws and close to the scanning width Ws. When the non-detection range is provided at both ends of the scanning range, the width Wnd of one non-detection range is set to ½ of the value obtained by subtracting the detection range width Wd from the scanning width Ws, and Wnd = (Ws− Wd) / 2 (S2).

  Next, the width Wo of the overlapping range is set based on the width Wnd of the non-detection range. The width Wop of the overlapping range between the paths can be determined based on the width Wnd of the non-detection range. Further, the width Woe of the overlapping range between the electron guns may be set to the same size as the width Wop of the overlapping range between the paths, or may be set to a different size (S3).

  Each electron gun scans for each pass, and acquires and stores signal images for all panels in units of passes. FIG. 10A schematically shows a signal image obtained when the electron gun G1 scans the paths P1 to P4. FIG. 10 shows an example in which pixels are driven in a grid pattern, and “x” marks in the figure indicate lit pixels (S4).

  The signal image of the detection range is read from the signal image of the scanning range acquired for each pass and combined to form the signal image of the scanning range. In the combination of the signal images, the signal image of the non-detection range is supplemented by using the signal image of the overlapping range of adjacent paths or the overlapping range of adjacent electron gun paths. FIG. 10B schematically shows a signal image formed by combining the signal images obtained in the paths P1 to P4 in FIG. 10A (S5).

  A lit pixel or a non-lit pixel is detected from the combined signal image. This pixel detection can be obtained based on, for example, a drive pattern. For example, when detecting a lighting pixel, it can be a pixel driven by a driving pattern applied to the panel (S6).

  The pixel intensity of the detected pixel is calculated from the signal intensity of the signal image (S7), and defect detection is performed by comparing the calculated signal intensity with a threshold value (S8).

  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 TFT array inspection apparatus 2 Stage 3 Electron gun 4 Detector 5 Electron beam scanning control part 6 Stage drive control part 7 Control part 10 Signal processing part 10a Signal image formation part 10b Storage part 10c Reading part 10d Coupling part 10e Pixel detection part 10f Pixel coordinate calculation unit 10g Pixel intensity calculation unit 11 Defect detection unit 20 Panel 21 Scan range 21L Scan range 21R Scan range 22 Detection range 22L Detection range 22R Detection range 23 Non-detection range 23L Non-detection range 23R Non-detection range 24 Overlapping range 24L Overlap Range 24R Overlapping range 24a Overlapping range 24b Overlapping range 24c Overlapping range 30 pixels 100 Substrate 101 Panel A Detection range B Detection range D Detection range Wd Detection range width Wnd Non-detection range width Wo Overlap range width Wp Pixel width Ws Scan width P1 P4 path G1-G The electron gun
a2 Detection range
b2 Detection range
d2 Detection range

Claims (6)

A test signal of a predetermined voltage is applied to the panel of the TFT substrate to drive the array, the pixel corresponding to the array is irradiated on the panel with an electron beam, and secondary electrons emitted by the electron beam irradiation are detected. In the TFT substrate array inspection method for inspecting the TFT substrate array based on the detection signal of the secondary electrons,
The electron beam scans a scanning range on the TFT substrate with a constant scanning width regardless of the size of the pixel,
A detection signal acquired by scanning the electron beam forms a signal image of the scanning range,
The signal image is divided into a detection range in which pixel defect detection is performed and a non-detection range in which pixel defect detection is not performed.
The non-detection range is both end portions in the scanning direction of the electron beam in the signal image, and the width in the scanning direction of each portion of the both end portions is determined based on the width in the scanning direction of the pixels,
A TFT substrate array inspection method comprising: detecting a defect of a pixel based on a signal intensity of a signal image in the detection range, and detecting an array corresponding to the defective pixel detected by the defect detection as a defect array.   2. The TFT substrate array inspection method according to claim 1, wherein a width of the non-detection range in the scanning direction is a width of the pixel in the scanning direction. The scanning range includes a plurality of scanning ranges adjacent in the scanning direction, and the two adjacent scanning ranges have overlapping ranges that overlap each other,
In the scanning of each scanning range, at least the non-detecting range of the adjacent scanning range is scanned by the scanning of the overlapping range,
3. The TFT substrate array inspection method according to claim 1, wherein a signal image in one detection range in the overlapping range is used as a signal image in the other non-detection range adjacent to each other. A test signal of a predetermined voltage is applied to the panel of the TFT substrate to drive the array, the pixel corresponding to the array is irradiated on the panel with an electron beam, and secondary electrons emitted by the electron beam irradiation are detected. In the TFT substrate array inspection apparatus for inspecting the array of TFT substrates based on the detection signal of the secondary electrons,
An electron beam scanning controller for scanning the electron beam on the TFT substrate;
A signal processing unit that calculates a signal intensity for performing defect determination of the TFT substrate array based on the detection signal;
A defect determination unit that performs an array defect determination based on the signal intensity obtained by the signal processing unit;
The electron beam scanning control unit scans a scanning range having a constant scanning width regardless of the size of the pixel,
The signal processing unit forms a signal image of the scanning range from a detection signal acquired by scanning of the electron beam, and the signal image is detected without detecting a defect of a pixel and a detection range of detecting a defect of the pixel. The non-detection range is an end portion of the signal image in the scanning direction of the electron beam, and the width in the scanning direction of each portion of the both end portions is the width in the scanning direction of the pixel. Based on
The defect determination unit detects a defect of a pixel based on a signal intensity of a signal image in the detection range, and detects an array corresponding to the defective pixel detected by the defect detection as a defect array. TFT substrate array inspection equipment.   5. The TFT substrate array inspection apparatus according to claim 4, wherein the width of the non-detection range in the scanning direction is a width of the pixel in the scanning direction. The scanning range includes a plurality of scanning ranges adjacent in the scanning direction, and the two adjacent scanning ranges have overlapping ranges that overlap each other,
The electron beam scanning control unit scans at least the non-detection range of the adjacent scanning range by scanning the overlapping range in the scanning of each scanning range,
6. The TFT substrate array according to claim 4, wherein the signal processing unit uses a signal image in one detection range in the overlapping range as a signal image in the other non-detection range adjacent to each other. Inspection device.