JP2007057813A - Positioning method of substrate, and sample stage using same, and dimension measuring device or substrate processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning method of a substrate or a positioning device therefor, with which an original point of the substrate is corrected without depending on a mechanical clamp mechanism. <P>SOLUTION: In two planes in a vertical (Y) direction and in a horizontal (X) direction to be reference planes of the substrate, which are references in an exposing device for pattern exposure, positions identical to places hit and pressed with a clamp pin of the mechanical clamp mechanism (end face positions of a substrate to be inspected) are detected with an image pickup device, and runs of a stage transferring along X and Y axes and linearity of the pattern in the substrate to be inspected are corrected based on information detected for both planes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention performs image processing such as dimension measurement or image processing for substrate processing such as pattern exposure by combining a microscope and an image sensor (for example, an area sensor such as a television camera) that captures an enlarged subject image by the microscope. Alignment (linearity) that corrects the linearity of the substrate surface by detecting the running or linearity of the stage that moves the subject (LCD substrate, etc.) mounted on the sample stage to the XY axis, and the end surface of the substrate that is the subject. ) About detection.

  Each substrate of the inspection substrate is mounted on a substrate mounted on a sample table such as an LCD substrate inspection device or pattern exposure substrate processing device by a mechanical clamp mechanism equipped with pressing pins on each surface of the sample table. There is a method in which positioning is performed by pressing a surface to correct the linearity of the pattern in the inspection substrate (see, for example, Patent Document 1).

JP 2004-186681 A

The material of the substrate is mainly glass, and the sample stage on which the inspection substrate is mounted is well known to be made of aluminum, glass, pins, or the like. For example, in the case of LCD substrates, until the third generation (550 mm x 650 mm), the LCD substrate was also small, and there was no problem with positioning the LCD substrate with the mechanical clamp mechanism. However, in the recent 7th generation, the substrate size has increased to 1950 mm × 2250 mm, and the LCD substrate and sample stage are stuck by static electricity, making it difficult to position the LCD substrate using the mechanical clamp mechanism. It is coming.
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to correct the origin of the substrate without using a mechanical clamp mechanism, a positioning method using the same, and a sample stage using the same And a dimension measuring device or a substrate processing device.

  In order to achieve the above object, the present invention provides a reference surface (two surfaces: longitudinal (Y) direction and lateral (X) direction) of a substrate when a pattern is exposed by an exposure apparatus, and a mechanical clamp mechanism. The same position (end surface position of the inspection board) as the location where the clamp pin is pressed is detected by the imaging device, and based on the information on both detected faces, the stage running along the XY axis and alignment of the pattern on the inspection board (Linearity) is corrected.

In other words, the positioning method of the present invention controls the whole of a microscope for enlarging a subject image, an imaging device for capturing the enlarged subject image as a video signal, an image processing device for recognizing a pattern in a substrate from the video signal. In a positioning method of a sample stage in which a subject equipped with a control PC is placed and moved to an arbitrary position, substrate positioning or substrate end face alignment (linearity) correction is performed in a non-contact manner.
Preferably, in the positioning method of the present invention, the video signal of the end face of the substrate is detected by image processing, and the positioning of the substrate or the alignment (linearity) of the end face of the substrate is corrected.

In other words, the sample stage of the present invention controls the whole of a microscope for enlarging a subject image, an imaging device for capturing the enlarged subject image as a video signal, an image processing device for recognizing a pattern in a substrate from the video signal. In a sample stage on which a subject equipped with a control PC is placed and moved to an arbitrary position, positioning of the substrate or alignment (nonlinearity) of the substrate end face is performed in a non-contact manner.
Preferably, the sample stage of the present invention detects a video signal on the end face of the substrate by image processing and corrects the positioning of the substrate or the alignment (linearity) of the end face of the substrate.
Also preferably, the sample stage of the present invention is equipped with a reflecting plate that reflects illumination on the opposite side of the imaging device that images the end face of the substrate.

That is, the dimension measuring apparatus or the substrate processing apparatus according to the present invention includes a microscope for enlarging a subject image, an imaging device for capturing the enlarged subject image as a video signal, an image processing device for recognizing a pattern in the substrate from the video signal, and a subject. This is a dimension measuring device or substrate processing device consisting of an XYZ stage unit that moves an arbitrary position and a control PC that controls the entire device, and is equipped with a function to perform alignment (linearity) of the substrate end face in a non-contact manner.
Preferably, the dimension measuring apparatus or the substrate processing apparatus of the present invention detects a video signal of the end face of the substrate by image processing and corrects the positioning of the substrate or the alignment (linearity) of the end face of the substrate.
Preferably, the dimension measuring apparatus or the substrate processing apparatus of the present invention is equipped with a reflecting plate that reflects illumination on the side opposite to the imaging apparatus that images the end face of the substrate.
Preferably, the dimension measuring apparatus or the substrate processing apparatus of the present invention is equipped with a correction function by detecting the alignment (linearity) of the in-substrate pattern from the alignment information of the substrate end face.

  According to the present invention, even if the inspection substrate to be inspected is enlarged, for example, the LCD substrate is the seventh generation and the substrate size is 1950 mm (vertical) × 2250 mm (horizontal)) If the transfer accuracy of the transfer robot is within the field of view of an image sensor such as a CCD camera for detecting the reference plane position, it is possible to always perform stable alignment correction of the XY stage and the pattern movement in the substrate. In addition, because of the non-contact method, the substrate end face is not damaged during clamping by the mechanical clamp mechanism.

  An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention. In this embodiment, the substrate to be inspected is described as an LCD substrate, and the image sensor is described as a CCD camera.

  The LCD substrate 2 is transferred to the sample stage 1 by the substrate transfer robot 13 and moved to the Y axis on which the measurement CCD camera 5, the X axis position detection optical system 6 and the Y axis position detection optical system 7 are mounted. The X-axis stage 3 that moves the main body of the Y-axis stage 4 and the Y-axis stage 4 to the X-axis is a mechanism that can move the position of the entire area of the LCD substrate 2.

  The sample stage 1 is equipped with a reflector 8. The reflecting mirror 8 is an optical for X-axis position detection on the Y position reference surface 9 of the LCD substrate 2 and the X position reference surface 10 of the LCD substrate, which is a reference in an exposure apparatus when forming a pattern on the two surfaces of the LCD substrate. The purpose is to reflect the illumination of the system 6 and the Y-axis position detection optical system 7 respectively, and two sets are provided for the Y position reference plane 9 and the X position reference plane 10.

  The image processing device 11 is used to measure the line width of the pattern formed on the LCD substrate 2 from the video signal imaged by the measurement CCD camera 5 and converted into an electric signal, and the X-axis position detection optical system 6 and the Y-axis. This is a processing device for detecting position information from the video signal of each reference plane of the LCD board that is captured by the position detection camera 14 equipped with the position detection optical system 7 and converted into an electrical signal. And the processing result is displayed on the monitor 12.

Next, details of the position detection optical system of the present invention will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a position detection optical system according to the position embodiment of the present invention.
The sample stage 1 is slightly smaller (for example, 3 mm) than the outer periphery of the LCD substrate 2, and the illumination of the X-axis position detection optical system 6 and the Y-axis position detection optical system 7 is reflected below the LCD substrate 2. Each reflector 8 is equipped.

  As the X-axis stage 4 and the Y-axis stage 5 move, the X-axis position detection optical system 6 and the Y-axis position detection optical system are placed above the end surfaces of the Y position reference surface 9 and the X position reference surface 10 of the LCD substrate. 7 is configured to be arranged. This position detection optical system (X-axis position detection optical system 6 and Y-axis position detection optical system 7) includes a lens 16 that determines the field of view to be imaged and a coaxial illumination unit 15 that illuminates the optical path system, Furthermore, it comprises a CCD camera 14 for position detection that captures an image magnified by the lens 16 and a power source 17 for illumination.

  The field of view of the lens 16 is determined by the reproducibility of the transfer position of the LCD substrate transfer robot that transfers the LCD substrate 2 to the sample table 1. For the seventh generation (1950 mm × 2250 mm), it is about ± 10 mm. Generally, the magnification is such that the CCD camera 14 for position detection can capture a field of view of approximately 34 mm × 25 mm (horizontal (X-axis direction) × vertical (Y-axis direction)).

Next, the details of the position reference planes 9 and 10 of the LCD substrate 2 and the relationship between the image captured by the position detecting CCD camera 14 and its luminance waveform will be described with reference to FIG. FIG. 3 is an enlarged view (FIG. 3A) of the reference surface portion of the inspection board of one embodiment of the present invention, an image obtained by imaging the reference surface (FIG. 3B), and luminance of the image obtained by imaging the reference surface. It is a figure which shows a waveform (FIG.3 (c)). Note that the LCD substrate 2 is actually still present on the right side of FIG. 3, but it is also complicated and is omitted for the sake of explanation.
Moreover, the solid line arrow is irradiation light, and the broken line arrow is reflected light.

In FIG. 3, the outer part A of the LCD substrate 2 (the portion without the LCD substrate 2 when the reflection plate 8 is viewed from the upper part of the apparatus) is the brightest because the illumination light is totally reflected by the reflection plate 8. In addition, since the tip of the LCD substrate 2 is rounded, the light irradiated to the B portion hardly reflects. This is the darkest.
Location C where LCD substrate 2 and reflector 8 overlap and location D of LCD substrate 2 on sample stage 1 may be interchanged depending on the material of sample stage 1. Medium brightness (brightness level).

  The detection of the position reference plane part (information of Y position reference plane 9 and information of X position reference plane 10) of LCD substrate 2 is the most from the left side of the detection area in the luminance waveform 19 of the video signal on the scanning line 18 of the CCD camera. This is possible by detecting a position corresponding to an arbitrary slice level, with the high level being 100% and the lowest level being 0%.

  The actual edge of the LCD substrate 2 may be missing. For this reason, detection accuracy is improved by detecting and averaging the end face positions at a plurality of arbitrary slice levels.

  Next, based on the detected information on the Y position reference plane 9 and the information on the X position reference plane 10, we will explain how to correct the linearity of the pattern formed on the LCD substrate 2 and the running of the stage that moves to the actual XY axes. 4 will be described. FIG. 4 is a diagram for explaining the principle of correcting the linearity of the present invention, and is a schematic view of the inspection board viewed from the upper side of the apparatus.

The straightness 21 of the X-axis stage movement and straightness 22 of the Y-axis stage movement depend on the performance of the XY stage, but it is generally about 5 μm, and the mechanical origin of the XY stage (SXO, SYO) 28 is all This is the reference origin of the position and is always the same position.
The position of the reference position (GXO, GYO) 27 on the LCD board 2 is shifted within a range of ± 10 mm depending on the transfer position of the board transfer robot 13, and the angle θ may also be reversed, so it always changes.

The positional relationship between the origin position (GXO, GYO) 27 of the LCD board 2 and the pattern origin position (PXO, PYO) 26 in the LCD board 2 depends on the accuracy of the exposure device that exposes the pattern on the LCD board 2, and is actually Is within the design value ± 1 μm.
The pattern origin position (PXO, PYO) 26 is a position used as a reference when a thin film (wiring, resist, etc.) is formed on the surface of the inspection target substrate such as the LCD substrate 2 by vapor deposition or the like.

The above information and Y position reference detection position (YALX, YALY) 23, Y position reference detection position (YARX, YARY) 24, X position reference detection position (XAX, XAY) 25, Y position reference detection position (YALX, YALY) To the design value (XAY-GYO) from the reference value (YALX-GXO) up to the reference origin (GXO) of the LCD board and the reference position (XAY) of the X position to the reference origin (GYO) of the LCD board.
The deviation angle θ between the X axis straight line 21 and the Y position reference plane (for example, the Y position reference detection positions 23 and 24) is obtained as follows.

θ = tan ^-1 ((YALY-YARY) / (YALX-YARX) Equation (1)
The reference origin (GYO) of LCD board 2 is
GYO = YALY + ((YALX-GXO) x tan θ) (2)
The reference origin (GXO) of LCD board 2 is
GXO = XAX + ((XAY-GYO) x tan θ) Equation (3)

Below, by adding the design values from the origin position (GXO, GYO) 27 of the LCD board 2 to the pattern origin position (PXO, PYO) 26 in the LCD board 2, the machine origin (SXO, SYO) 28 of the XY stage is added. It is possible to calculate the relative position from the position, and the linearity is corrected from the position data of the arbitrary pattern formation area in the LCD substrate 2 and θ.

  In the above-described embodiments, the inspection apparatus has been described. However, the present invention can be applied to any apparatus using image processing that uses a sample stage (stage) on which a substrate is placed, such as a substrate processing apparatus. It is also applicable to a device.

As described above, even if the substrate on which the inspection device or processing device is placed becomes large, if the transfer accuracy of the substrate transfer robot is within the field of view of the image sensor for detecting the reference plane position, the substrate can be easily positioned. it can. That is, it is possible to always perform stable alignment correction of the XY stage running and the in-substrate pattern running.
In addition, because of the non-contact method, the substrate end face is not damaged during clamping by the mechanical clamp mechanism.

1 is a block diagram showing the overall configuration of an embodiment of the present invention. Explanatory drawing which shows the optical system system for position detection of the position Example of this invention. The figure which shows the luminance waveform of the enlarged view of the reference plane part of the test | inspection board of one Example of this invention, the image which imaged the reference plane, and the image which imaged the reference plane. The figure for demonstrating the principle which correct | amends the linearity of this invention.

Explanation of symbols

  1: Sample stage, 2: LCD substrate, 3: X axis stage, 4: Y axis stage, 5: CCD camera for measurement, 6: Optical system for X axis position detection, 7: Optical system for Y axis position detection, 8 : Reflector, 9: Y position reference plane of LCD substrate, 10: X position reference plane of LCD substrate, 11: Image processing device, 12: Monitor, 13: Substrate transport robot, 14: CCD camera for position detection, 15: Coaxial illumination unit, 16: lens, 17: power supply for illumination, 18: CCD camera scanning line, 19: luminance waveform, 20: pattern formation area, 21: X axis straight, 22: Y axis straight, 23: Y position reference Detection position (YALX, YALY), 24: Y position reference detection position (YARX, YARY), 25: X position reference detection position (XAX, XAY), 26: Pattern origin position (PXO, PYO), 27: LCD board Reference origin (GXO, GYO), 28: XY stage mechanical origin (SXO, SYO).

Claims (9)

A subject comprising a microscope for enlarging a subject image, an imaging device for capturing the enlarged subject image as a video signal, an image processing device for recognizing a pattern on a substrate from the video signal, and a control PC for controlling the whole In the positioning method of the sample stage which is placed and moves to an arbitrary position, the positioning of the substrate or the alignment of the substrate end face is performed in a non-contact manner. 2. The positioning method according to claim 1, wherein a video signal of the end face of the substrate is detected by image processing, and the positioning of the substrate or the alignment of the end face of the substrate is corrected. A subject comprising a microscope for enlarging a subject image, an imaging device for capturing the enlarged subject image as a video signal, an image processing device for recognizing a pattern on a substrate from the video signal, and a control PC for controlling the whole In the sample stage which is placed and moves to an arbitrary position, the substrate is positioned or the substrate end face is aligned in a non-contact manner. 4. The sample stage according to claim 3, wherein a video signal of the end face of the substrate is detected by image processing, and the positioning of the substrate or the alignment of the end face of the substrate is corrected. 5. The sample stage according to claim 3, further comprising: a reflecting plate that reflects illumination on a side opposite to an imaging device that images the end face of the substrate. A microscope for enlarging the subject image, an imaging device for capturing the enlarged subject image as a video signal, an image processing device for recognizing a pattern on the substrate from the video signal, an XYZ stage unit for moving the subject at an arbitrary position, and the entire device are controlled. A dimension measuring apparatus or a substrate processing apparatus, characterized in that a dimension measuring apparatus or substrate processing apparatus comprising a control PC is equipped with a function for performing alignment of the substrate end face in a non-contact manner. 7. A dimension measuring apparatus or a substrate processing apparatus according to claim 6, wherein a video signal of the end face of the substrate is detected by image processing, and the positioning of the substrate or the alignment of the end face of the substrate is corrected. Substrate processing equipment. 8. A dimension measuring apparatus or a substrate processing apparatus according to claim 6, wherein a reflecting plate for reflecting illumination is provided on the side opposite to the imaging device for imaging the end face of the substrate. Equipment or substrate processing equipment. 9. The dimension measuring apparatus or the substrate processing apparatus according to claim 6, wherein the dimension measurement apparatus is equipped with a correction function by detecting the alignment of the pattern in the substrate from the alignment information of the substrate end face. Measuring device or substrate processing device.

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