WO2013065143A1

WO2013065143A1 - Liquid crystal array inspection device, and method for acquiring images captured by liquid crystal array inspection device

Info

Publication number: WO2013065143A1
Application number: PCT/JP2011/075288
Authority: WO
Inventors: 正道永井
Original assignee: 株式会社島津製作所
Priority date: 2011-11-02
Filing date: 2011-11-02
Publication date: 2013-05-10
Also published as: JP5692669B2; JPWO2013065143A1; CN103907017B; CN103907017A

Abstract

In order to eliminate cumulative errors in an imaging range generated on the basis of the movement resolution of a moving stage, and improve the positional accuracy of defect detection in liquid crystal array inspections, this liquid crystal array inspection device applies a test signal of a prescribed voltage to a liquid crystal substrate to drive an array, captures images of the liquid crystal substrate on the basis of a signal, such as a secondary electron beam obtained by irradiating the liquid crystal substrate with charged particles, such as an electron beam, and inspects the liquid crystal substrate array on the basis of the captured images obtained by the abovementioned imaging operations. The liquid crystal array inspection device: detects movement variations in a moving part that moves the liquid crystal substrate, and corrects the movement speed of the moving part on the basis of the movement variations, and movement intervals when performing each imaging operation; and corrects a cumulative error produced by the accumulation of errors generated on the basis of movement resolutions associated with the correction of the movement intervals. In an imaging operation performed a plurality of times, the correction of a cumulative error involves carrying out only a movement resolution of the moving part for each prescribed number of imaging operations by correcting the movement interval.

Description

Liquid crystal array inspection apparatus and method for acquiring captured image of liquid crystal array inspection apparatus

The present invention relates to a liquid crystal array inspection apparatus that inspects a liquid crystal array using a captured image obtained by capturing an image on a liquid crystal substrate, and more particularly to acquisition of a captured image.

In a liquid crystal array inspection apparatus, a scanning image obtained by two-dimensionally scanning a charged particle beam such as an electron beam or an ion beam on a substrate can be used.

For example, in the manufacturing process of the TFT array substrate used in the TFT display device, an inspection is performed as to whether or not the manufactured TFT array substrate is driven correctly. In this TFT array substrate inspection, the TFT array substrate is scanned using, for example, an electron beam as a charged particle beam, and the inspection is performed based on a captured image obtained by scanning. (Patent Documents 1 and 2)

As an example of an array inspection apparatus, for example, an inspection signal is applied to an array of a liquid crystal substrate to be inspected, and a charged particle beam such as an electron beam or an ion beam is scanned two-dimensionally on the substrate, and a captured image obtained by beam scanning An array inspection apparatus that performs substrate inspection based on the above is known. In array inspection, secondary electrons emitted by electron beam irradiation are detected by converting them into analog signals using a photomultiplier or the like, and array defects are determined based on the signal intensity of the detection signals.

The array inspection is performed on the basis of the signal intensity of the captured image at the detected pixel position by detecting the pixel position on the captured image obtained by scanning. The pixel position is detected by performing image processing on the captured image to detect pixel coordinates, and arranging the detected pixel coordinates in accordance with the pixel arrangement set on the liquid crystal substrate.

When detecting the pixel position on the picked-up image, the pixel position on the picked-up image may be displaced due to the movement error of the stage on which the liquid crystal substrate is placed. When a pixel position is detected based on a captured image that has been displaced in this way, a deviation occurs between the pixel position set with respect to the substrate and the detected pixel position, and a different pixel is associated with the set pixel position. Inconvenience may occur. The displacement of the detected pixel position becomes a factor that decreases the accuracy of defect detection, and an erroneous determination that a defective pixel is determined to be normal or that a normal pixel is determined to be defective occurs.

Therefore, in order to eliminate such inconvenience and increase the accuracy of defect detection, high positional accuracy is required for the captured image.

JP 2004-271516 A JP 2004-309488 A

The captured image of the liquid crystal substrate is performed by scanning the liquid crystal substrate with charged particles while moving the moving stage on which the liquid crystal substrate is placed. In a case where a captured image of a liquid crystal substrate is acquired by scanning charged particles on the substrate, an imaging range acquired by an imaging operation by a single scan is limited.

Therefore, in order to acquire a captured image of the entire liquid crystal substrate, it is necessary to acquire a captured image of each imaging range by repeating the imaging operation and to connect these captured images.

In order to obtain a captured image of the entire liquid crystal substrate by connecting a plurality of captured images in this way, each captured image is required to have no positional deviation.

However, since mechanical operations such as stage operations generally include errors, positional errors occur in captured images due to these errors. As a cause of displacement due to mechanical operation, there is expansion of a driving mechanism such as a ball screw that drives the moving stage. In order to suppress the occurrence of such a displacement of the captured image, it is necessary to correct the displacement of the imaging operation.

In order to correct the positional deviation of this imaging operation, a mark is provided at a predetermined position on the moving stage, and this mark is recognized by an imaging means such as a camera fixed on the inspection apparatus side during the operation of the moving stage. It is conceivable to detect a positional deviation by comparing the mark position detected on the captured image with the reference position of the mark and correct the imaging operation based on the detected positional deviation.

As correction of this imaging operation, the actual moving distance of the moving stage is calculated based on the positional deviation obtained from the recognition of the mark, and the moving speed and imaging range of the moving stage are corrected using the calculated actual moving interval. Can be considered.

11 and 12 are diagrams for explaining misalignment correction by correcting the moving speed of the moving stage and the imaging range.

FIG. 11 shows an example when the moving stage is not displaced, and FIG. 12 shows an example when the moving stage is displaced.

In FIG. 11, when the moving stage is not displaced, the mark setting position (FIG. 11 (a)) and the mark position detected by photographing with a fixed camera (FIG. 11 (b)). There is no misalignment between them. In this case, the movement interval of the stage position for performing each imaging operation is a constant Lo (FIG. 11C). In the imaging operation, an imaging trigger is generated based on the constant movement interval Lo (FIG. 11D), and imaging is performed based on each imaging trigger. The imaging trigger can be generated when the moving amount of the moving stage is monitored and the moving amount becomes the moving interval Lo. The imaging range of each imaging is determined corresponding to the movement interval Lo of the moving stage (FIG. 11 (e)), and a captured image is acquired by imaging within this imaging range (FIG. 11 (f)).

When the moving stage is not misaligned, no misalignment occurs between the plurality of captured images, so that the entire captured image of the substrate can be acquired by connecting the captured images.

In FIG. 12, when the moving stage is displaced, the mark setting position (FIG. 12 (a)) and the mark position detected by photographing with a fixed camera (FIG. 12 (b)). In the meantime, a displacement Δl is detected. This positional deviation Δl indicates the amount of positional deviation that occurs during the distance from the reference position such as the end of the moving stage to the mark.

基づい Based on this positional deviation Δl, the moving speed of the moving stage is corrected and the imaging range is corrected. By correcting the imaging range, the movement interval of the stage position where each imaging operation is performed is corrected to Lc (FIG. 12C). In the imaging operation, an imaging trigger is generated based on the corrected correction movement interval Lc (FIG. 12D), and imaging is performed based on each imaging trigger. The imaging trigger can be generated when the moving amount of the moving stage is monitored and the moving amount reaches the correction moving interval Lc. The imaging range of each imaging is determined corresponding to the correction movement interval Lc of the moving stage (FIG. 12 (e)), and all the captured images are acquired by connecting the captured images obtained in each imaging range (FIG. 12). (F)).

As described above, the inventors of the present application may not be able to sufficiently correct the displacement of the moving stage by correcting the moving speed and imaging range of the moving stage. It has been found that there is a cumulative correction error caused by a deviation from the moving resolution of.

The position of the moving stage is corrected using the moving resolution as the minimum unit. Therefore, the correction amount can be accurately corrected if the positional deviation correction amount is an integral multiple of the movement resolution. However, if the positional deviation correction amount is not an integral multiple of the movement resolution, there is a correction error in each imaging range. As a result, the correction error of each imaging range is accumulated for the entire imaging range and an accumulated error occurs.

The accumulated error of the positional deviation caused by the moving resolution of the driving mechanism of the moving stage is a position error that is not corrected even if the moving speed of the moving stage and the imaging range are corrected.

13 and 14 are diagrams for explaining the accumulated error. FIG. 13 shows an example of a positive accumulated error, and FIG. 14 shows an example of a negative accumulated error.

13 and 14, the displacement of the moving stage is determined by setting the mark position (FIGS. 13A and 14A) and the mark position detected by photographing with a fixed camera (FIG. 13B). , FIG. 14 (b)) is detected by the positional deviation Δl. Based on this positional deviation Δl, the moving speed of the moving stage is corrected and the imaging range is corrected. In the correction of the imaging range, the correction amount of the movement interval that can be corrected by the moving stage is an integer multiple N of the moving resolution s of the moving stage.

An error of dL occurs based on the moving resolution in the moving distance of the actual moving stage with respect to the moving distance after correction obtained by calculation as Lc. FIG. 13C shows a case where the corrected moving interval Lc ⁺ of the actual moving stage is longer than the corrected moving interval Lc obtained in the calculation, and FIG. 14C shows the corrected moving interval of the actual moving stage. In this example, Lc ^- is a movement distance after correction obtained by calculation shorter than Lc.

In the imaging operation, an imaging trigger is generated based on the corrected correction movement intervals Lc ⁺ and Lc ⁻ (FIGS. 13D and 14D), and imaging is performed based on each imaging trigger. The imaging trigger can be generated when the moving amount of the moving stage is monitored and the moving amount becomes the correction moving interval Lc ⁺ , Lc ⁻ . The imaging range of each imaging is determined corresponding to the correction movement intervals Lc ⁺ and Lc ⁻ of the moving stage (FIGS. 13 (e) and 14 (e)), and the captured images obtained in each imaging range are joined together. All captured images are acquired (FIGS. 13 (f) and 14 (f)).

All the captured images obtained by joining the captured images have an accumulated error in which the error dl generated in each captured image is accumulated. In the case shown in FIG. The accumulated error is longer than the imaging range, and in the case shown in FIG. 14, the entire captured image is shorter than the target imaging range by the accumulated error.

FIG. 15 is a diagram for explaining the accumulated error. FIG. 15A shows a case where there is no cumulative error of the moving mechanism of the moving stage, FIG. 15B shows a case where a positive cumulative error occurs, and FIG. 15C shows a negative cumulative error. Shows the case.

When there is no expansion amount of the moving mechanism of the moving stage in FIG. 15A, the imaging range captured by each imaging trigger is Lo, and the entire imaging range is M · Lo. M represents the number of times of imaging for acquiring the entire imaging range.

When the positive accumulated error of FIG. 15B occurs, the error dl (= Lc ⁺ −Lc) generated in each imaging is accumulated to generate the accumulated error, and the negative error of FIG. When a cumulative error occurs, an error dl (= Lc−Lc ⁻ ) generated in each imaging is accumulated to generate a cumulative error.

As described above, when a difference in the length of the accumulated error occurs between the total captured image obtained by joining and the target imaging range, if the pixel position is determined based on the total captured image, A positional deviation occurs between the pixel value and an error occurs at the defective position when the defect inspection is performed based on the pixel position having the positional deviation.

Therefore, the present invention solves the above-described conventional problems, eliminates the accumulated error of the imaging range that occurs based on the moving resolution of the moving stage, and improves the position accuracy of defect detection in the liquid crystal array inspection.

The present invention applies an inspection signal of a predetermined voltage to a liquid crystal substrate to drive the array, and images the liquid crystal substrate based on a secondary electron signal obtained by irradiating the liquid crystal substrate with charged particles such as an electron beam. In a liquid crystal array inspection apparatus that inspects an array of liquid crystal substrates based on a captured image obtained by the imaging, a movement variation of a moving unit that moves the liquid crystal substrate is detected, and a moving speed of the moving unit is detected based on the movement variation. And the movement interval at the time of each imaging are corrected, and the accumulated error generated by accumulating errors generated based on the movement resolution accompanying the correction of the movement interval is corrected. The correction of the accumulated error is performed by correcting the movement interval by the moving resolution of the moving unit every predetermined number of times of imaging performed a plurality of times.

The movement interval is corrected by, for example, calculating the number of corrections by dividing the accumulated error occurring in the entire imaging range by the movement resolution, and correcting the movement interval by dividing the total number of imagings by the calculated number of corrections. The interval can be determined.

The present invention can be an aspect of a liquid crystal array inspection apparatus and an aspect of a liquid crystal array inspection method.

The aspect of the liquid crystal array inspection apparatus of the present invention drives the array by applying an inspection signal of a predetermined voltage to the liquid crystal substrate, images the liquid crystal substrate based on a signal obtained by irradiating the liquid crystal substrate with a charged particle beam, A liquid crystal array inspection apparatus that inspects an array of liquid crystal substrates based on a captured image obtained by the imaging includes a moving unit, an imaging unit, a captured image forming unit, a fluctuation detecting unit, and an imaging correction unit. The charged particles can be electron beams, and secondary electrons obtained at this time are detected as detection signals.

The moving unit is a component that moves the liquid crystal substrate, and can be, for example, a moving stage on which the liquid crystal substrate is placed and moved. The moving stage may be a stage mechanism that can move in the two-dimensional direction in the XY directions, or a stage mechanism that can move in the three-dimensional direction by adding movement in the Z direction to movement in the XY directions.

The imaging unit is a component that divides and images the liquid crystal substrate, and starts imaging whenever the liquid crystal substrate moves a distance corresponding to a predetermined movement interval as the liquid crystal substrate is moved by the moving unit. Every time imaging starts, the imaging unit performs imaging with the moving interval as an imaging range, and repeats the imaging operation with the moving interval as the imaging range in each imaging operation. A plurality of divided captured images are acquired by repeated imaging operations.

The captured image forming unit connects a plurality of divided captured images acquired by the imaging unit to form one combined captured image.

The fluctuation detector detects movement fluctuations of the moving part. The movement fluctuation includes fluctuation caused by expansion of the movement mechanism of the moving unit.

The imaging correction unit corrects imaging conditions when the imaging unit acquires a captured image based on the fluctuation range and fluctuation direction of the movement fluctuation of the moving unit detected by the fluctuation detection unit.

In one mode of the liquid crystal array inspection apparatus of the present invention, the moving unit has a moving stage on which the liquid crystal substrate is mounted and moved, and the imaging correction unit uses the moving interval that defines the imaging range as an imaging condition, and the moving unit moves Correct based on fluctuations.

The imaging correction unit includes a movement interval correction unit that corrects the movement interval, and a cumulative error correction unit that corrects an accumulated error caused by accumulating correction errors of the movement interval by the movement interval correction unit.

The movement interval correction unit calculates the corrected movement interval based on the fluctuation range and fluctuation direction of the movement fluctuation detected by the fluctuation detection unit. The cumulative error correction unit corrects the cumulative error by using the minimum resolution of the moving stage as a correction amount and increasing or decreasing the correction amount to the correction movement interval calculated by the movement interval correction unit.

The cumulative error correction unit increases or decreases the correction amount with respect to the correction movement interval for every predetermined number of times of imaging. The amount of increase / decrease in the correction amount and the number of times of increase / decrease are calculated based on the fluctuation range and direction of movement fluctuation.

One form of the fluctuation detection unit includes a photographing means fixed on the liquid crystal array inspection apparatus. The photographing unit photographs a mark provided on the moving stage, and detects a movement variation of the moving unit based on a positional deviation of the mark image in the photographed image.

The imaging correction unit can include a speed correction unit that corrects the moving speed of the moving stage in addition to the movement interval correction unit and the cumulative error correction unit. The speed correction unit calculates a correction speed based on the fluctuation range and fluctuation direction of the movement fluctuation detected by the fluctuation detection unit.

The liquid crystal array inspection apparatus of the present invention is characterized in that the imaging correction unit includes a cumulative error correction unit, and the correction amount is set to the correction movement interval calculated by the movement interval correction unit, with the minimum resolution of the moving stage as the correction amount. By increasing / decreasing the value, an error that occurs every time the movement interval correction unit performs correction when performing divided imaging correction corrects an accumulated error formed for all captured images.

Next, an aspect of the liquid crystal array inspection method of the present invention is a secondary electron obtained by applying an inspection signal of a predetermined voltage to the liquid crystal substrate to drive the array and irradiating the liquid crystal substrate with charged particles such as an electron beam. In a picked-up image acquisition method of a liquid crystal array inspection apparatus that picks up an image of a liquid crystal substrate based on the signal of the liquid crystal and inspects an array of the liquid crystal substrate based on a picked-up image obtained by the picking, And a variation detection step and an imaging correction step.

The moving process moves the liquid crystal substrate. The imaging process starts imaging every time the liquid crystal substrate moves by a predetermined movement interval in accordance with the movement of the liquid crystal substrate by the moving process. Each time imaging is started, the moving interval is imaged as an imaging range, and a one-division captured image is acquired. A plurality of divided captured images are acquired by repeating the imaging operation with the movement interval as the imaging range in each imaging operation.

In the captured image forming process, a plurality of divided captured images acquired in the imaging process are connected to form one combined captured image.

The fluctuation detection process detects movement fluctuation of the liquid crystal substrate that moves in the movement process.

The imaging correction process corrects imaging conditions when the imaging process acquires a captured image based on the fluctuation range and fluctuation direction of the movement fluctuation of the liquid crystal substrate in the movement process detected in the fluctuation detection process.

In one form of the liquid crystal array inspection method, the moving step moves the liquid crystal substrate placed on a moving stage, and the imaging correction step corrects the imaging operation using the moving interval that defines the imaging range as an imaging condition.

The imaging correction step includes a movement interval correction step that corrects the movement interval, and a cumulative error correction step that corrects a cumulative error caused by accumulating correction errors of the movement interval in the movement interval correction step.

In the movement interval correction step, the correction movement interval is calculated based on the fluctuation width and fluctuation direction of the movement fluctuation detected by the fluctuation detection step. In the cumulative error correction step, the magnitude of the minimum resolution of the moving stage is used as a correction amount, and this correction amount is increased or decreased to the correction movement interval calculated in the movement interval correction step to correct the cumulative error.

In the accumulated error correction step, the correction amount is increased or decreased with respect to the correction movement interval every predetermined number of times of imaging. The amount of increase / decrease in the correction amount and the number of times of increase / decrease can be calculated based on the fluctuation range and fluctuation direction of the movement fluctuation.

In the fluctuation detection process, a mark provided on the moving stage is photographed by photographing means fixed on the liquid crystal array inspection apparatus, and movement fluctuation in the movement process is detected based on the positional deviation of the mark image in the photographed image.

The imaging correction process can include a speed correction process for correcting the moving speed of the moving stage in addition to the movement interval correction process and the cumulative error correction process. In the speed correction step, a correction speed is calculated based on the fluctuation range and fluctuation direction of the movement fluctuation detected by the fluctuation detection step to perform speed correction.

According to the present invention, it is possible to eliminate the accumulated error of the imaging range that occurs based on the moving resolution of the moving stage and improve the position accuracy of the liquid crystal substrate defect detection.

FIG. 1 is a schematic block diagram for explaining a configuration example of a liquid crystal array inspection apparatus of the present invention. It is a flowchart for demonstrating the schematic process by the liquid crystal test | inspection apparatus of this invention. It is operation | movement explanatory drawing for demonstrating the schematic process by the liquid crystal test | inspection apparatus of this invention. It is a figure for demonstrating correction | amendment of a positive accumulation error. It is a figure for demonstrating correction | amendment of a negative accumulation error. It is a flowchart for demonstrating the 1st correction example of an accumulation error. It is a figure for demonstrating the 1st example of correction | amendment of an accumulation error. It is a flowchart for demonstrating the 2nd correction example of an accumulation error. It is a figure for demonstrating the 2nd correction example of an accumulation error. It is a figure for demonstrating the schematic structural example of the signal processing part of the liquid crystal test | inspection apparatus of this invention. It is a figure for demonstrating the position shift correction | amendment by correction | amending the moving speed and imaging range of a moving stage. It is a figure for demonstrating the position shift correction | amendment by correction | amending the moving speed and imaging range of a moving stage. It is a figure for demonstrating the position shift correction | amendment by correction | amending the moving speed and imaging range of a moving stage. It is a figure for demonstrating the position shift correction | amendment by correction | amending the moving speed and imaging range of a moving stage. It is a comparison figure for demonstrating an accumulation error.

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

Schematic configuration of the liquid crystal inspection apparatus of the present invention will be described with reference to the schematic explanatory diagram of FIG. 1, and schematic processing by the liquid crystal inspection apparatus of the present invention will be described with reference to the flowchart of FIG. 2 and the operation explanatory diagram of FIG.

FIG. 1 is a schematic block diagram for explaining a configuration example of a liquid crystal array inspection apparatus of the present invention. Note that the example shown in FIG. 1 shows a configuration example in which an electron beam is irradiated on the liquid crystal substrate, secondary electrons emitted from the liquid crystal substrate are detected, and a captured image is acquired from the detected intensity.

In FIG. 1, a liquid crystal array inspection apparatus 1 includes a moving stage 2 on which a liquid crystal substrate 100 is placed and can be conveyed in the X and Y directions, and an electron gun 3A disposed above the moving stage 2 and away from the moving stage 2. And a detector 3B that detects secondary electrons emitted from pixels (not shown) of the panel 101 of the liquid crystal substrate 100.

The movement of the moving stage 2 is controlled by the stage drive control unit 4, and the electron gun 3A is controlled by the imaging control unit 3C to irradiate an electron beam and scan on the liquid crystal substrate 100. The detection signal of the secondary electrons detected by the detector 3B is processed by the signal processing unit 10 and used for inspection such as pixel defect determination in the inspection unit 20. The electron gun 3A, the detector 3B, and the imaging control unit 3C constitute the imaging unit 3, and acquire a captured image of the liquid crystal substrate.

The drive operation of each part of the imaging control unit 3C, the stage drive control unit 4, the signal processing unit 10, and the inspection unit 20 is controlled by the control unit 9. The control unit 9 has a function of performing control including the entire operation of the liquid crystal 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 moving stage 2 mounts the liquid crystal substrate 100 and is movable in the X-axis direction and the Y-axis direction by the stage drive control unit 4. Further, the electron beam emitted from the electron gun 3A can be swung in the X-axis direction or the Y-axis direction by the imaging control unit 3C. The stage drive control unit 4 and the imaging control unit 3C independently or cooperatively scan the electron beam on the liquid crystal substrate 100 to obtain a captured image of the liquid crystal substrate 100. The fixed camera 5 images a mark provided on the moving stage 2.

FIGS. 2 and 3 are a flowchart and an explanatory diagram for explaining a procedure for calculating a correction amount for correcting a displacement of the moving stage in acquiring a captured image in the liquid crystal array inspection of the present invention.

In the procedure for calculating the correction amount, the displacement amount ΔL of the moving stage is obtained by the steps S1 to S4, and the moving speed of the moving stage is corrected based on the displacement ΔL obtained in the steps S1 to S4 by the step S5. The correction speed is calculated, the correction movement interval for correcting the movement interval L of the movement stage that determines the imaging interval by the steps S6 and S7, and the frequency of the correction operation for correcting the accumulated error are calculated.

In step S6, a corrected moving interval Lc for correcting the moving interval L of the moving stage that determines the imaging interval is calculated based on the positional deviation ΔL obtained in steps S1 to S4. In the step S7, when the movement interval is corrected by the correction movement interval Lc calculated in the step S6, the frequency of the correction operation performed to correct the accumulated error caused by the moving resolution of the moving stage is calculated.

Here, it is assumed that for the moving stage, vo is preset as the set stage speed, and Lo is preset as the moving distance of the moving stage that determines each imaging interval. As a result, the moving stage generates an imaging trigger every time the moving stage moves the moving distance Lo while moving at the set stage speed vo, and performs an imaging operation in response to the imaging trigger to perform imaging corresponding to the moving distance Lo. A captured image of the range is acquired. By repeating the movement of the moving stage, the generation of the imaging trigger, and the acquisition of the captured image by the imaging trigger, the captured image of the entire imaging range is acquired.

FIG. 3A is a diagram showing an outline of the imaging operation. The panel 101 on the substrate 100 is scanned and imaged while moving the moving stage 2, and the entire imaging range is obtained by a plurality of imaging operations. Are obtained by stitching together the captured images.

Therefore, when there is no fluctuation in the moving speed of the moving stage and there is no position shift in the moving stage, an imaging trigger is generated every time the moving stage moves by the moving distance Lo, and an imaging operation is performed. By acquiring and stitching together a plurality of captured images obtained by the operation, it is possible to obtain all captured images without having a positional shift in the pixels.

On the other hand, when there are error factors such as fluctuations in the moving speed of the moving stage and displacements of the moving stage, misalignment is included in the captured image obtained by each imaging operation due to these errors. A plurality of captured images having these positional shifts are acquired and connected to form a total captured image, and when the pixel position is specified based on the total captured image, a positional shift occurs in the pixel position, and an accurate pixel position is determined. I can't.

Therefore, in order to detect displacement of the moving stage, a mark for detecting displacement is provided at a predetermined position of the moving stage, and based on this mark, fluctuations in moving speed of the moving stage and displacement of the moving stage are detected. To detect.

After positioning the moving stage at a reference position such as the end position, the moving stage starts to move (S1). After starting to move the moving stage, the moving amount of the moving stage is monitored. The moving amount of the moving stage can be monitored based on, for example, the output of an encoder provided in the moving stage or the rotation amount of a motor that drives the moving mechanism of the moving stage.

When the monitored moving amount reaches the preset moving distance La (S2), the mark provided on the moving stage is photographed by the fixed camera. The set movement distance La can be set to a distance between the reference position and the mark, for example, and is set to a position where the mark can be imaged by the fixed camera. A mark provided on the moving stage is photographed by a fixed camera fixed on the liquid crystal array inspection apparatus side (S3), and a difference between the mark position on the photographed image and a preset mark position is obtained.

3A, the mark 102 provided on the moving stage 2 is photographed by the fixed camera 5. FIG. 3B shows an example of an image obtained by a fixed camera. In the image example, the mark position on the image is shifted from the predetermined mark position by a positional shift Δl.

When there is no deviation in the moving speed or position of the moving stage, the mark position on the captured image is the same as the preset mark position. On the other hand, when there is a shift in the moving speed or position of the moving stage, the mark position on the captured image is shifted from a preset mark position, and the shift amount depends on the moving speed and the position shift amount.

Since the positional deviation amount Δl between the mark position on the captured image and the preset mark position is a positional deviation amount with respect to the movement distance La from the reference position, the positional deviation amount ΔL with respect to the entire imaging range is calculated. This positional deviation amount ΔL can be obtained, for example, by adding the ratio of (length of entire imaging range / movement distance La) to the positional deviation amount Δl of the mark position.

When the ratio between the length of the entire imaging range and the movement distance La is known, the relationship between the positional deviation amount Δl of the mark position and the positional deviation amount ΔL with respect to the entire imaging range is expressed by an arithmetic expression or a data table. It can be obtained in advance by calculating and reading out the ratio as a parameter (S4).

In the step of calculating the correction amount of the speed of S5, the fluctuation speed v is
v = (Lo + Δl) / Δt = vo + Δv
It is expressed by the following formula. In the above equation, Lo is a predetermined moving distance of the moving stage, Δl is the amount of displacement of the mark position, Δt is a time required for the moving stage to move the predetermined moving distance Lo, vo is a set stage speed, and Δv is a speed. It is a fluctuation.

Since the speed correction of the moving stage can be performed by reducing the speed fluctuation Δv, the speed correction vc is
vc = -Δv
Can be expressed as

Next, in step S6, a corrected movement interval obtained by correcting the movement interval L is calculated. The positional deviation amount ΔL calculated in the step S4 is a positional deviation amount with respect to the entire imaging range. In order to correct this positional deviation amount ΔL by dispersing it in each captured image, the positional deviation amount ΔL is divided by M times to calculate a correction amount ΔL / M for each imaging, and the movement interval of each imaging is calculated as a correction amount ΔL. The correction movement interval Lc is calculated by correcting for / M. Here, M is the number of captured images.

Therefore, in order to acquire the imaging range of each captured image, the correction movement interval Lc at which the moving stage moves is Lc = Lo + ΔL / M
It is represented by

Here, ΔL / M represents a correction amount for correcting each imaging range. FIG. 3C shows the relationship among the set movement interval Lo, the correction movement interval Lc, and the correction amount ΔL / M.

The correction movement interval Lc can be corrected by shifting the imaging trigger for starting the imaging operation by the correction amount ΔL / M (S6).

Here, when the moving stage has a moving resolution capable of accurately moving the correction amount ΔL / M, the moving interval can be corrected without excess or deficiency. However, the moving stage is driven. Since the moving resolution of the drive mechanism is limited, if the correction amount ΔL / M is not an integral multiple of the moving resolution, a correction error occurs for each correction.

When the moving resolution of the moving stage is s, the correction amount that can be corrected by the moving stage is (n · s) that is an integer multiple of the resolution s. Therefore, the correction amount ΔL / M of the correction movement interval at which the moving stage moves is expressed by the following equation: ΔL / M = n · s + δ
It is represented by Here, δ (<s) represents a correction error.

Therefore, in each imaging range, every time correction is performed, a correction error that is less than the moving resolution s occurs at the maximum. Due to this correction error, an accumulated error corresponding to a maximum of M · s occurs in the entire imaging range.

Note that the cumulative error in the + direction and the cumulative error in the-direction have the same size with a half size of one imaging range as a boundary, so the maximum cumulative error is half the size of one imaging range.

∙ Eliminate the accumulated error by correcting the corrected movement interval calculated in S6. In this correction of the accumulated error, the imaging range is set by a corrected moving interval Lcc obtained by correcting the corrected moving interval Lc calculated in step S6 by the moving resolution s of the stage every predetermined number of times in a plurality of imaging operations. Do that.

The movement interval that determines each imaging range by correcting the correction movement interval is a combination of the correction movement interval Lc calculated in S6 and the correction movement interval Lcc. The frequency of changing to the corrected moving interval Lc and the corrected moving interval Lcc can be calculated from the magnitude of the accumulated error and the moving resolution. The accumulated error is eliminated by changing the corrected movement interval Lc to the corrected movement interval Lcc every predetermined number of times. FIG. 3D shows a state where the correction movement interval Lcc is introduced (S7).

Next, correction of the accumulated error will be described with reference to FIGS. FIG. 4 shows a case where a positive cumulative error is eliminated, and FIG. 5 shows a case where a negative cumulative error is eliminated.

When the cumulative error is a positive cumulative error in the + direction, the entire imaging range is longer than the imaging range when there is no cumulative error. This increase is corrected by setting the correction movement interval Lc to the correction movement interval Lcc (<Lc).

In FIG. 4C, a correction movement interval Lcc <Lc) is introduced after a predetermined number of correction movement intervals Lc, and an imaging trigger is generated based on the correction movement intervals Lc and Lcc (FIG. 4D). Imaging is performed for the imaging range (FIG. 4E). As a result, the entire imaging range in which the accumulated error is eliminated is acquired (FIG. 4 (f)).

When the cumulative error is a negative negative cumulative error, the entire imaging range is shorter than the imaging range when there is no cumulative error. This decrease is corrected by setting the correction movement interval Lc to the correction movement interval Lcc (> Lc).

FIG. 15D shows a case where the accumulated error is corrected. According to FIG. 15D, the accumulated error in FIGS. 15B and 15C is corrected, and the imaging range based on the captured image is the same as that without the accumulated error shown in FIG. 15A. ing.

In FIG. 5C, a correction movement interval Lcc (> Lc) is introduced after a predetermined number of correction movement intervals Lc, and an imaging trigger is generated based on the correction movement intervals Lc and Lcc (FIG. 5D). Then, imaging is performed for the imaging range (FIG. 5E). As a result, the entire imaging range in which the accumulated error is eliminated is acquired (FIG. 5 (f)).

Next, an example of correcting the accumulated error will be described using the flowcharts of FIGS. 6 and 8 and the explanatory diagrams of FIGS.

A first correction example of the accumulated error will be described with reference to FIGS.
In the first correction example, first, a correction error dL generated in one imaging is calculated.
This correction error dL is
dL = n · s-ΔL / M
It is represented by

Here, ΔL is a positional deviation amount with respect to the entire imaging range, and as shown in the step of S4, the positional deviation amount ΔL is set to the positional deviation amount Δl of the mark position (length of entire imaging range / movement distance La). It can obtain | require by integrating | accumulating the ratio of. M is the number of a plurality of captured images, and ΔL / M obtained by dividing the positional deviation amount ΔL by M represents a correction amount per imaging (FIG. 7A).

When this correction amount ΔL / M is corrected with the moving resolution s of the moving stage, the interval that can be corrected by the moving stage is (n · s), which is an integer n times the moving resolution s, so the correction error dL is ( n · s−ΔL / M) (FIG. 7B), (S6a).

Next, a cumulative error dLL that generates M times of imaging is calculated.
Since the correction error amount dL calculated in the process of S6a is a correction error amount generated in one imaging range, when a correction error amount dL occurs in each imaging range, the accumulated error amount dLL of the entire imaging range is
dLL = (dL ・ M)
(Fig. 7 (c, d)).

Next, the frequency of correcting the correction movement interval Lc is calculated. The cumulative error dLL is corrected by switching the correction movement interval Lc to the correction movement interval Lcc. Here, an example is shown in which switching to the corrected movement interval Lcc is performed uniformly with respect to all the movement intervals, and the corrected movement interval Lc is switched to the corrected movement interval Lcc every predetermined number of times.

The correction of one correction movement interval Lcc is performed by increasing or decreasing the movement resolution s by the correction movement interval Lc. Accordingly, by switching one correction movement interval Lc to the correction movement interval Lcc, the accumulated error dLL is corrected by the movement resolution s.

The accumulated error dLL can be corrected by switching dLL / s (= dL · M / s) correction movement intervals Lc among the M correction movement intervals Lc to the correction movement intervals Lcc.

Therefore, when switching the correction movement interval at equal intervals, the cumulative error dLL is corrected by switching the correction movement interval Lc to the correction movement interval Lcc every M / (dLL / s) = s / dL times. (FIG. 7 (e)), (S6c).

A second correction example of the accumulated error will be described with reference to FIGS.
In the second correction example, similarly to the first correction example, first, a correction error dL that occurs in one imaging is calculated.

This correction error dL is
dL = n · s-ΔL / M
It is represented by

Here, ΔL is a positional deviation amount with respect to the entire imaging range, and as shown in the step of S4, the positional deviation amount ΔL is set to the positional deviation amount Δl of the mark position (length of entire imaging range / movement distance La). It can obtain | require by integrating | accumulating the ratio of. M is the number of the plurality of captured images, and ΔL / M obtained by dividing the positional deviation amount ΔL by M represents the correction amount per image capture (FIG. 9A).

When this correction amount ΔL / M is corrected with the moving resolution s of the moving stage, the interval that can be corrected by the moving stage is (n · s), which is an integer n times the moving resolution s, so the correction error dl is ( n · s−ΔL / M) (FIG. 9B), (S8A).

Next, the number of times that the accumulated error dLL becomes the moving resolution s is calculated (S8B). Since the correction error generated by one imaging is dL, the accumulated error dLL becomes the moving resolution s by imaging of s / dL times, and is expressed by the following equation.
Cumulative error dLL = dL ・ (s / dL) = s

Therefore, the accumulated error can be corrected by switching the correction movement interval Lc to the correction movement interval Lcc for every s / dL times of imaging (FIGS. 9C to 9E) and (S8C).

A schematic configuration example of the signal processing unit 10 of the liquid crystal inspection apparatus of the present invention will be described with reference to FIG.
The signal processing unit 10 corrects the imaging condition when the imaging unit acquires a captured image based on the variation detection unit 10A that detects the movement variation of the moving stage and the movement variation of the moving stage detected by the variation detection unit 10A. The imaging correction unit 10B and a captured image forming unit 10C that joins a plurality of divided captured images to form one combined captured image.

The fluctuation detection unit 10A is configured so that the fixed camera that captures the photographing signal of the fixed camera 5 and forms a photographed image uses the forming unit 10a and the shift amount of the mark provided on the moving stage based on the photographed image. And a stage mark deviation amount detection unit 10b that detects the variation.

The imaging correction unit 10B includes a speed correction unit 10c, a movement interval correction unit 10d, an accumulated error correction unit 10e, and a correction data storage unit 10f. The imaging interval is set as an imaging condition with a moving stage speed and a movement interval forming an imaging trigger. These imaging conditions are corrected based on the amount of deviation formed by the variation detector 10A.

The speed correction unit 10c corrects the speed of the moving stage based on the deviation amount. The stage drive control unit 4 performs speed control based on the correction speed of the speed correction unit 10c.

The movement interval correction unit 10d corrects the movement interval based on the shift amount, corrects the timing of the imaging trigger for performing imaging, and corrects the imaging range. The imaging control unit 3C performs imaging control based on the corrected movement interval of the movement interval correction unit 10d.

In the corrected movement interval formed by the movement interval correction unit 10d, the cumulative error is corrected by the cumulative error correction unit 10e. The correction processing of the movement interval correction unit 10d and the cumulative error correction unit 10e can be performed using data stored in the correction data storage unit 10f.

The captured image forming unit 10C includes a detection signal acquisition unit 10g that receives a detection signal of the detection unit 3B and a captured image formation unit 10h that forms a captured image from the acquired detection signal. The captured image forming unit 10h performs an imaging operation based on the imaging trigger formed by the imaging control unit 3C.

The calculation process of the present invention can be applied not only to a liquid crystal array inspection apparatus but also to a semiconductor element substrate inspection.

DESCRIPTION OF SYMBOLS 1 Liquid crystal array inspection apparatus 2 Moving stage 3 Imaging part 3A Electron gun 3B Detection part 3C Imaging control part 4 Stage drive control part 5 Fixed camera 6 Stage drive control part 9 Control part 10 Signal processing part 10A Fluctuation detection part 10B Imaging correction part 10C Captured image forming unit 10a Fixed camera image forming unit 10b Stage mark deviation amount detection unit 10c Speed correction unit 10d Movement interval correction unit 10e Cumulative error correction unit 10f Correction data storage unit 10g Detection signal acquisition unit 10h Captured image formation unit 20 Inspection unit 100 LCD panel 101 Panel 102 Mark dL Correction error dLL Cumulative error L Movement interval La Set movement distance Lc Correction movement interval Lcc Correction movement interval Lo Movement interval s Movement resolution v Fluctuating speed vc Speed correction vo Setting stage speed

Claims

An inspection signal of a predetermined voltage is applied to the liquid crystal substrate to drive the array, the liquid crystal substrate is imaged based on a signal obtained by irradiating the liquid crystal substrate with charged particles, and the liquid crystal is based on the captured image obtained by the imaging A liquid crystal array inspection apparatus for inspecting an array of substrates,
A moving unit for moving the liquid crystal substrate;
Imaging is started each time the liquid crystal substrate moves by a predetermined movement interval as the liquid crystal substrate is moved by the moving unit, and a plurality of divisions are performed by repeating the imaging operation with the movement interval as the imaging range in each imaging operation. An imaging unit for acquiring a captured image;
A captured image forming unit that connects the plurality of divided captured images to form one combined captured image;
A fluctuation detecting unit for detecting movement fluctuations of the moving unit;
An imaging correction unit that corrects an imaging condition when the imaging unit acquires a captured image based on a movement variation of the moving unit detected by the variation detection unit;
The liquid crystal array inspection apparatus, wherein the imaging correction unit corrects the imaging condition based on a fluctuation range and a fluctuation direction of the movement fluctuation.
The moving unit has a moving stage on which a liquid crystal substrate is placed and moved,
The imaging correction unit uses the movement interval that defines the imaging range as an imaging condition,
A movement interval correction unit that corrects the movement interval; and a cumulative error correction unit that corrects a cumulative error caused by accumulating correction errors of the movement interval by the movement interval correction unit,
The movement interval correction unit calculates a correction movement interval based on a fluctuation range and a fluctuation direction of movement fluctuation detected by the fluctuation detection unit.
The cumulative error correction unit corrects the cumulative error by increasing or decreasing the correction amount to the correction movement interval calculated by the movement interval correction unit using the minimum resolution of the moving stage as a correction amount. The liquid crystal array inspection apparatus according to claim 1.
The cumulative error correction unit performs the increase / decrease of the correction amount with respect to the correction movement interval every predetermined number of times of imaging, and calculates the increase / decrease amount and the increase / decrease number of the correction amount based on the fluctuation width and fluctuation direction of the movement fluctuation. The liquid crystal array inspection apparatus according to claim 2, characterized in that:
The variation detection unit includes a photographing unit fixed on the liquid crystal array inspection apparatus,
4. The imaging device according to claim 1, wherein the imaging unit images a mark provided on the moving stage and detects a movement variation of the moving unit based on a positional deviation of the mark image in the captured image. The liquid crystal array inspection apparatus according to one.
The imaging correction unit includes a speed correction unit that corrects the moving speed of the moving stage,
The liquid crystal array inspection according to claim 1, wherein the speed correction unit calculates a correction speed based on a fluctuation range and a fluctuation direction of the movement fluctuation detected by the fluctuation detection unit. apparatus.
An inspection signal of a predetermined voltage is applied to the liquid crystal substrate to drive the array, the liquid crystal substrate is imaged based on a signal obtained by irradiating the liquid crystal substrate with charged particles, and the liquid crystal is based on the captured image obtained by the imaging A method for acquiring a captured image of a liquid crystal array inspection apparatus for inspecting an array of substrates,
A moving step of moving the liquid crystal substrate;
Imaging is started each time the liquid crystal substrate moves by a predetermined movement interval in accordance with the movement of the liquid crystal substrate in the moving step, and the imaging operation with the movement interval as the imaging range is repeated in each imaging operation to perform a plurality of divisions. An imaging process for acquiring a captured image;
A captured image forming step of connecting the plurality of divided captured images to form one combined captured image;
A fluctuation detecting step for detecting movement fluctuation in the moving step;
An imaging correction step of correcting an imaging condition when the imaging step acquires a captured image based on movement fluctuation of the movement step detected in the variation detection step;
The method for acquiring a captured image of a liquid crystal array inspection apparatus, wherein the imaging correction step corrects the imaging condition based on a fluctuation range and a fluctuation direction of the movement fluctuation.
In the moving step, the liquid crystal substrate is placed on a moving stage and moved,
In the imaging correction step, a moving interval that defines an imaging range is set as an imaging condition,
A movement interval correction step of correcting the movement interval; and a cumulative error correction step of correcting a cumulative error caused by accumulating correction errors of the movement interval by the movement interval correction step,
The movement interval correction step calculates a correction movement interval based on a fluctuation range and a fluctuation direction of the movement fluctuation detected by the fluctuation detection step.
The cumulative error correction step uses the magnitude of the minimum resolution of the moving stage as a correction amount, and corrects the cumulative error by increasing or decreasing the correction amount to the correction movement interval calculated in the movement interval correction step. A captured image acquisition method for a liquid crystal array inspection apparatus according to claim 6.
The cumulative error correction step performs the increase / decrease of the correction amount with respect to the correction movement interval every predetermined number of times of imaging, and calculates the increase / decrease amount of the correction amount and the number of increase / decreases based on the fluctuation width and fluctuation direction of the movement fluctuation. The captured image acquisition method of the liquid crystal array inspection apparatus according to claim 7,
In the variation detection step, a mark provided on the moving stage is photographed by photographing means fixed on a liquid crystal array inspection apparatus, and movement variation in the movement step is detected based on a positional deviation of the mark image in the photographed image. The captured image acquisition method of the liquid crystal array inspection apparatus according to any one of claims 6 to 8.
The imaging correction step includes a speed correction step of correcting the moving speed of the moving stage,
10. The liquid crystal array inspection according to claim 6, wherein the speed correction step calculates a correction speed based on a fluctuation range and a fluctuation direction of the movement fluctuation detected by the fluctuation detection step. A captured image acquisition method of an apparatus.