JP2007107945A - Inspection device of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an inspection device of a substrate, which performs macro-inspection and micro-inspection continuously, from becoming large-scaled to enhance inspection efficiency. <P>SOLUTION: The inspection device 1 of the substrate is constituted so that a flotation stage 4 for floating the substrate W by air is laid on a base main body 3, and an automatic macro-inspection part 21 and an automatic micro-inspection part 22 are successively arranged to the area from one end part of the base main body 3 to the other end part thereof. The automatic macro-inspection part 21 has an illumination part 24 for irradiating the substrate W with linear illumination light and the reflected light of the illumination light is folded back by a reflecting part 25 to be thrown on an imaging part 26. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate inspection apparatus used for inspecting a substrate such as a flat panel display of a liquid crystal display.

  In a manufacturing process of a flat panel display (FPD) such as a liquid crystal display (LCD), a substrate inspection apparatus is used in a process of inspecting the appearance of the substrate. Some substrate inspection apparatuses include a defect detection unit and a defect review unit arranged along a uniaxial stage (see, for example, Patent Document 1). The defect detection unit includes a detection camera and transmitted illumination, and the defect review unit includes a color camera and transmitted illumination.

Further, the substrate inspection apparatus includes a substrate inspection apparatus that performs an appearance inspection using a macro inspection that macroscopically observes the entire substrate macroscopically and a micro inspection that inspects for the presence or absence of relatively small defects using a microscope. is there. Such an appearance inspection apparatus is arranged in a macro inspection unit, and a rocking holder for macro inspection that sets a glass substrate carried by a transfer robot at an angle suitable for visual observation, and a glass substrate from the rocking holder. It is known to have an XY stage that transfers to a receiving micro-inspection area, and is provided with a micro-inspection microscope at a position outside the macro illumination area of the macro-inspection section (see, for example, Patent Document 2).
JP 2000-9661 A JP 2001-305064 A

However, in the substrate inspection apparatus disclosed in Patent Document 1, when the glass substrate to be inspected is enlarged, visual inspection becomes difficult, and the burden on the inspector increases. Further, when the substrate is enlarged, when registering the position of a defect or the like, an operation unit such as a joystick is operated to move a pointer over the detected defect, so that the inspection time becomes longer. Furthermore, in order to swing a large substrate, it is necessary to provide a large space and a sturdy swing mechanism, which increases the size of the apparatus.
The present invention has been made in view of such circumstances, and an object of the present invention is to prevent an increase in the size of a substrate inspection apparatus that can perform macro inspection and micro inspection continuously, and to improve inspection efficiency.

  The present invention for solving the above problems is arranged on the upstream side of the stage, a stage for transporting the flat panel display substrate, transport means for holding one side of the substrate and transporting it in the transport direction of the stage, A light source for line illumination that emits line-shaped illumination light extending in a direction that intersects the transport direction, a micro inspection unit that has an imaging unit that captures an observation region irradiated by the line-shaped illumination light, and a transport direction of the stage A micro inspection unit having an objective lens that moves in a direction perpendicular to the transport direction, a defect coordinate calculation unit that calculates coordinates of defects detected by the micro inspection unit, and a defect coordinate calculation unit Based on the coordinate data of each defect, the substrate is moved to a position where the X coordinate of the defect coincides with the scanning line of the objective lens, and the substrate is stopped. And a control unit that moves the objective lens of the micro inspection unit to a position that coincides with the Y coordinate of the defect, and a precision that is arranged in the inspection region corresponding to the scanning line of the objective lens and that causes the substrate to float with high accuracy. A substrate inspection apparatus comprising a floating block, wherein the substrate is floated and the substrate is micro-inspected by the micro-inspection unit.

  In this substrate inspection apparatus, the macro inspection unit irradiates the substrate with linear illumination light, and acquires a macroscopic image (macro image) of the substrate surface from the reflected light. At this time, if the moving means acquires an image while moving the substrate, an image of the substrate surface is automatically obtained. The micro inspection unit acquires an enlarged image (micro image) at a predetermined position of the substrate by moving the substrate and the objective lens, respectively.

  According to the present invention, the macro inspection unit and the micro inspection unit are provided along the movement path of the substrate, and the macro inspection unit captures the reflected light from the substrate surface while moving the substrate, and automatically generates a macroscopic image. Since the enlarged image of the substrate is acquired by the micro inspection unit, the appearance inspection can be quickly performed regardless of the substrate size. If the presence or absence of a defect or the like is automatically detected from an image acquired by the macro inspection unit, a quicker and more accurate result can be obtained as compared with a case where inspection is performed manually. Further, if the position of the defect is registered and the micro inspection part is moved in accordance with this position, an enlarged image of a necessary place is obtained, and the inspection accuracy is improved.

The best mode for carrying out the present invention will be described below.
(First embodiment)
As shown in FIGS. 1 and 2, the board inspection apparatus 1 includes a base body 3 installed on a floor via a vibration isolation device 2, and air is blown out on the base body 3 as a board transfer means. A levitation stage 4 for levitation of the FPD glass substrate (glass substrate W) is laid. The levitation stage 4 has elongated levitation blocks (conveyance levitation blocks) 5 and 6 along a conveyance direction (longitudinal direction) of the glass substrate W from one end side in the longitudinal direction (X direction) of the base body 3. A plurality of intervals are provided, and the flying height of the glass substrate W can be controlled with high accuracy in the width direction (Y direction) perpendicular to the longitudinal direction of the flying blocks 5 and 6 in the middle of the flying stage 4. Precision levitation blocks (inspection levitation blocks) 7 and 9 are arranged with a predetermined gap 8 therebetween. These floating blocks 5 and 6 and precision floating blocks 7 and 9 are provided with a plurality of air blowing holes 10 (only part of which are shown in FIG. 1) opened at the upper surface thereof at equal intervals. . These air blowing holes 10 are connected to a fluid supply source 11 such as an air compressor.

  The precision levitation blocks 7 and 9 have air discharge holes 10 arranged more densely than the levitation blocks 5 and 6, or air discharge holes in addition to the air discharge holes 10, and air discharge force (positive pressure) Any method may be used as long as the flying height of the glass substrate W is controlled with high accuracy by the air suction force (negative pressure).

  Further, a guide rail 12 is laid in parallel with the levitation stage 4 on one side edge parallel to the longitudinal direction on the base body 3, and a substrate suction table 13 is movable on the guide rail 12. Is attached. In the substrate suction table 13, a suction portion 15 that sucks the glass substrate W is supported on a slide portion 14 such as a linear motor capable of self-running along the guide rail 12 so as to be movable up and down. A plurality of suction portions 15 are arranged at equal intervals along the longitudinal direction of the base body 3. A resinous suction pad is provided at the tip of each suction portion 15, and a through-hole penetrating vertically is formed in the suction pad. This through-hole is connected to a suction pump 17. Further, a plurality of reference pins 18 and pressing pins 19 that are positioning mechanisms are disposed in the carry-in area of the glass substrate W of the base body 3 so as to sandwich the glass substrate W. The reference pin 18 is movable up and down so that it can protrude and retract with respect to the upper surface of the levitation stage 4, and the pressing pin 19 is movable in the direction of the glass substrate. A substrate lift unit that lifts up the substrate W and allows the substrate to be replaced by the transfer robot is provided below the floating stage 4 in the glass substrate W loading area of the base body 3. A plurality of substrate lift portions are arranged so that the lift pins 20 that move up and down do not interfere with the robot hand of the transfer robot.

  Here, the base main body 3 includes an automatic macro inspection unit 21 that is a first inspection unit and a micro inspection unit 22 that is a second inspection unit, from one end to the other end. Arranged in order from the upstream side to the downstream side along the substrate transport direction of the levitation stage 4. The automatic macro inspection unit 21 has a portal frame 23 attached to the base body 3 so as to straddle the floating stage 4 in parallel with the Y direction, and illuminates along one side surface of the horizontal frame portion of the portal frame 23. The reflection part 25 and the imaging part 26 are attached to the upper surface of the horizontal frame part of the portal frame 23 at a position higher than the illumination part 24. The illumination unit 24 includes a line illumination light source 27 that emits elongated illumination light parallel to the Y direction toward the substrate surface. Examples of the line illumination light source 27 include a light source disposed on the end face of a rod-shaped rod lens. The reflection unit 25 is disposed on the optical path of the reflected light of the illumination light, and includes a mirror 28 that folds the reflected light toward the imaging unit 26. The imaging unit 26 includes a camera lens 29 and a line sensor camera 30 disposed on the other end side of the camera lens 29. The arrangement of the illumination unit 24, the reflection unit 25, and the imaging unit 26 is set so that the light reflected from the observation region of the substrate W is converged to form an image, and an interference image and diffraction on the surface of the substrate W are formed. In order to acquire an image, a line illumination light source 27 is rotatably provided so that an arbitrary incident angle can be set. Such an automatic macro inspection unit 21 is connected to a macro control unit 31. The macro control unit 31 performs light emission control of the line illumination light source 27 and capture of image data from the imaging unit 26, and performs image processing on the image data to create a macro image, which is registered in advance as the macro image. An image processing unit that performs pattern matching with a design pattern, a determination unit that determines the presence or absence of a defect according to the result of pattern matching, a defect coordinate calculation unit that calculates the position of the defect from the center of gravity of the defect, and a defect And a memory which is a registration means for registering the position.

  The micro inspection unit 22 includes a portal frame 40 attached to the base body 3 so as to straddle the floating stage 4 in parallel with the Y direction, and a guide laid along one side surface of the horizontal frame portion of the portal frame 40. It has a rail 41, a self-propelled inspection head stage 42 that is movable along the guide rail 41, and a microscope 43 supported by the inspection head stage 42. The microscope 43 is disposed above a gap 8 formed between the precision levitation blocks 7 and 9, and an illumination unit 45 that follows the movement of the microscope 43 along the guide rail 44 is disposed below the gap 8. Is provided. The microscope 43 includes an objective lens and a CCD (solid-state imaging device), and is provided at a position lower than the imaging unit 26 so as not to interfere with the imaging unit 26 of the automatic macro inspection unit 21. The output of the CCD of the microscope 43 is connected to the micro control unit 46. The micro control unit 46 is connected to the stage 42, the illumination unit 45, and the macro control unit 31.

The overall control of the substrate inspection apparatus 1 is controlled by the apparatus control unit 50. The apparatus control unit 50 is connected to the levitation stage 4, the substrate suction table 13, the pressing pin 19, the substrate lift unit, the macro control unit 31, and the micro control unit 46. In addition, a monitor 51 that displays an image and an operation unit 52 that receives an observer's operation are connected to the apparatus control unit 50.
Further, a flat substrate made of glass is used as the substrate W, and patterns such as wirings and filters are produced on the substrate W by using semiconductor technology. The defect of the substrate W means that the pattern is partially cut, the patterns are short-circuited, or a microscopic object with foreign matter attached, a filter film, or a temporary coating in the manufacturing process. Macroscopic patterns in which unevenness in the pattern itself such as a resist film is generated can be mentioned. Therefore, these patterns are inspection targets in this embodiment.

Next, the operation of this embodiment will be described.
First, air is blown upward from each air blowing hole 10 of the levitation stage 4, and the glass substrate W transferred by the transfer robot is transferred onto the levitation stage 4. Specifically, after each reference pin 18 is raised so as to protrude from the upper surface of the levitation stage 4, the glass substrate W is received from the transfer robot by the lift pins 20 with the substrate lift portion moved upward. The substrate lift is lifted down. As a result, the glass substrate W is levitated on the levitating stage 4 by air. In a state where the glass substrate W is floated, each pressing pin 19 is moved in the X direction or Y direction, the glass substrate W is applied to each reference pin 18 and positioning is performed, and then the suction pump 17 is driven. The glass substrate W is sucked and held by the suction pad 16 of the substrate suction table 13.

  After positioning and holding the substrate W, each reference pin 18 is lowered to a retracted position where it does not interfere with the substrate suction table 13 and the glass substrate W, and then the substrate suction table 13 is moved along the guide rail 12 to the other end (X Direction) at a constant speed. Line illumination light is irradiated onto the glass substrate W from the line illumination light source 27, and reflected light on the surface of the glass substrate W is imaged by the imaging unit 26. In this case, the substrate suction table 13 is moved back and forth in the macro inspection region, and the incident angle of the line illumination light source 27 is changed to an angle at which the diffracted light or interference light is imaged by the imaging unit 26 in the forward path and the backward path. The diffraction image and the interference image are captured.

  The macro control unit 31 performs pattern matching between the actual pattern formed by the image processing and the design pattern, and coordinates the center of gravity position of the defective portion that does not match the pattern with respect to the preset reference position of the substrate W. And is registered in the memory, and the defect coordinate data is transferred to the micro control unit 46. A macro image of the entire surface of the substrate W is formed by stacking data line by line in the image processing unit of the macro control unit 31 in synchronization with the timing at which the substrate W moves in the X direction. I do. As a result, when it is determined that there are a plurality of defects, all the determined defect coordinates are registered in order. Then, a macro image of the substrate W and a mark indicating a defect are output to the monitor 51. The inspector performs a micro inspection for each defect determined by the automatic macro inspection, and at this time, operates the operation unit 52 to designate the defect position. As a designation method, for example, a defect coordinate is acquired by clicking a mark on the screen with a mouse, or coordinates registered as a defect are read out in the order of registration or in order of distance.

  The micro inspection unit 22 acquires a micro image of the defect designated by the inspector. That is, the substrate suction table 13 is stopped at a position where the X coordinate of the defect to be inspected coincides with the scanning line (gap 8) of the objective lens of the microscope 43, and the microscope 43 and the illumination unit 45 are inspected. Align with the Y coordinate of the defect. At this time, the flying height of the glass substrate W is controlled with high precision by the precision flying blocks 7 and 9, and autofocus is executed in this state. Thereby, the illumination light emitted from the illumination unit 45 passes through the gap 8, passes through the substrate W and enters the microscope 43, and a micro image acquired by the microscope 43 is displayed on the monitor 51. Note that the micro inspection unit 22 may automatically acquire a micro image at a position determined as a defect by the automatic macro inspection unit 21 without waiting for the operation of the inspector.

  When the inspection is completed by transporting between the automatic macro inspection unit 21 and the micro inspection unit 22, the substrate suction table 13 is transported to the transfer position (the loading region of the glass substrate W) on one end of the levitation stage 4, After releasing the suction and holding of the substrate W, the substrate W is lifted up by the substrate lift unit. At this time, the suction pads of the suction portions 15 arranged on the substrate suction table 13 come into contact with the back surface of the glass substrate W, and the moving force of the glass substrate W floating on the air is regulated by the frictional force of the suction pads. Thereby, the glass substrate W is delivered to each lift pin 20 of a lift part in the positioned state. When inspecting another substrate W, the substrate W is replaced by the robot, and the same inspection is performed on the next substrate W.

According to this embodiment, since the diffracted light and the interference light are imaged by the imaging unit 26 while moving the substrate W in the X direction under line illumination light, the macro inspection for the entire substrate is automatically performed. Can do. Therefore, even a large substrate W can be inspected quickly and efficiently. Further, since it is not necessary to swing the substrate W to get up, it is not necessary to provide a large swing mechanism or a space for swinging. Furthermore, by performing defect determination automatically by pattern matching, it is possible to prevent variations in inspection by an inspector. When the pattern matching is performed, the coordinates of the portion determined to be a defect can be registered, so that the defect information can be easily used for other inspections.
Further, since the glass substrate W positioned by the same substrate suction table 13 can be transported between the automatic macro inspection unit 21 and the micro inspection unit 22 in the same apparatus, the substrates are replaced as in the past. In addition, it is not necessary to perform realignment, and the inspection time can be shortened. In addition, each defect extracted by the macro inspection unit 21 can be aligned with the micro inspection unit 22 with high accuracy. At this time, the movement of the substrate W in the X direction and the movement of the microscope 43 in the Y direction are performed on the basis of the coordinate information acquired from the automatic macro inspection unit 21. Micro inspection is possible.
Furthermore, since the position of both inspection parts 21 and 22 was made close by making the height of the imaging part 26 of the automatic macro inspection part 21 and the height of the microscope 43 of the micro inspection part 22 different, the board | substrate inspection apparatus 1 is changed. Can be downsized.

(Second Embodiment)
Other forms of the substrate inspection apparatus 1 include the following apparatus configuration.
In addition to the micro inspection unit 22, an automatic line width measurement unit may be provided as a second inspection unit that uses the inspection data of the automatic macro inspection unit 21. The automatic line width measurement unit obtains a micro image of a pattern registered in advance as an object for measuring the line width with the microscope 43, performs image processing on the micro image, and calculates the line width of the pattern.
Further, a spectroscopic measurement unit may be attached to the microscope 43 instead of or in addition to the CCD. The spectroscopic measurement unit is a spectroscope that splits visible light, and is attached mainly for measuring the spectral sensitivity of the color filter. The target for the spectroscopic measurement may be limited to positions registered in advance, or all color filters may be used.
By providing an automatic line width measurement unit and a spectroscopic measurement unit, in addition to macro inspection and micro inspection, line width measurement and spectral sensitivity measurement can be performed. Furthermore, if the line width threshold value for determining whether the pattern is good or bad and the spectral sensitivity are registered in the micro control unit 46 and compared with the measurement result, it is automatically set without passing through the inspector. An inspection can also be performed.

(Third embodiment)
As shown in the conceptual diagram of the automatic macro inspection unit 21 of the substrate inspection apparatus 1 shown in FIG. 3, the line illumination light source 27 is supported by the portal frame 23 (see FIG. 2) via the drive mechanism 60 so that the angle can be changed. In the imaging unit 26, an interference filter 61 is disposed in front of the lens 29 so as to be freely inserted into and removed from the optical path. In this substrate inspection apparatus 1, the substrate W is reciprocated according to the inspection conditions set by the automatic macro inspection unit 21, and for example, an interference image is acquired on the forward path and a diffraction image is acquired on the return path. When acquiring the interference image, the drive mechanism 60 is driven so that the incident angle θ1 of the illumination light to the substrate W is equal to the incident angle θ2 of the reflected light from the substrate W to the imaging unit 26. The illumination light source 27 is rotated with respect to the portal frame 22. Further, the interference filter 61 is inserted from the optical path immediately before the lens 29. Accordingly, as described above, image data is accumulated as the substrate W moves, and an interference image is acquired. Further, when acquiring the diffraction image, the angle of the line illumination light source 27 is set so that the incident angle θ1 becomes the diffraction angle of the nth-order light with respect to the incident angle θ2 to the image pickup unit 26, and the interference filter 61 is turned on. Evacuate from the street. As a result, as the substrate W moves, diffraction image data is accumulated and a diffraction image is acquired.

  In this embodiment, an interference image and a diffraction image can be acquired substantially simultaneously with the end of the reciprocation of the substrate W. After that, the micro inspection is performed or the substrate W is exchanged in accordance with preset conditions. When image processing is performed, the interference image processing is performed during the return path for acquiring the diffraction image, and the diffraction image processing is performed before the transition to the next step. According to this embodiment, it is possible to detect the presence or absence of film thickness unevenness from the interference image, and it is possible to detect abnormality of a fine pattern from the diffraction image, and even when performing macro inspection automatically, visual inspection An accuracy close to can be achieved.

The present invention is not limited to the above embodiments and can be widely applied.
For example, the substrate inspection apparatus 1 may include a known stage such as a free roller instead of the floating stage 4. Further, the substrate suction table 13 may be provided not only on one side edge portion but also on the other side edge portion to hold both side edges of the substrate W by suction.

It is a top view of the board | substrate inspection apparatus which concerns on embodiment of this invention. It is a side view of a board | substrate inspection apparatus. It is a conceptual diagram of an automatic macro inspection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board inspection apparatus 3 Base main body 4 Floating stage (stage, conveyance means)
5,6 Lifting block for transfer 7,9 Precision floating block 10 Air blowout hole 13 Substrate suction table (table, transfer means)
18 Reference Pin 19 Pressing Pin 21 Automatic Macro Inspection Unit 22 Micro Inspection Unit 24 Illumination Unit 26 Imaging Unit (Imaging Means)
27 Light Source for Line Illumination 31 Macro Control Unit 43 Microscope 45 Illumination Unit 46 Micro Control Unit 60 Drive Mechanism 61 Interference Filter W Glass Substrate (Flat Panel Display Substrate)
θ1, θ2 Incident angle

Claims (6)

A stage for carrying a flat panel display substrate;
Transport means for holding one side of the substrate and transporting the substrate in the transport direction of the stage;
A micro light source that is disposed upstream of the stage and that emits line illumination light that extends in a direction intersecting the transport direction, and an imaging unit that captures an observation region irradiated with the line illumination light. An inspection department;
A micro-inspection unit having an objective lens arranged in the transport direction of the stage and moving in a direction perpendicular to the transport direction;
A defect coordinate calculation unit that calculates the coordinates of the defect detected by the micro inspection unit;
Based on the coordinate data of each defect in the defect coordinate calculation unit, the substrate is moved to a position where the X coordinate of the defect coincides with the scanning line of the objective lens, and the micro inspection unit is in a state where the substrate is stopped. A control unit for moving the objective lens to a position coinciding with the Y coordinate of the defect;
A precision levitation block that is disposed in an inspection region corresponding to a scanning line of the objective lens and levitates the substrate with high accuracy;
A substrate inspection apparatus, wherein the substrate is micro-inspected by the micro-inspection unit in a state where the substrate is floated.   The substrate inspection apparatus according to claim 1, wherein the stage includes a plurality of elongate transfer floating blocks arranged at predetermined intervals along the transfer direction with the precision levitation stage interposed therebetween.   The precision floating block has an air blowing hole and an air discharge hole, and the flying height of the substrate is controlled with high accuracy by positive pressure and negative pressure. Board inspection equipment.   A substrate positioning mechanism including a plurality of reference pins and pressing pins is disposed in the substrate carry-in area of the stage so as to sandwich the four sides of the conveyed substrate, and the substrate is floated by the floating block for conveyance. The substrate inspection apparatus according to claim 2, wherein the substrate is positioned by pressing the substrate against the reference pin with the pressing pin.   The substrate inspection apparatus according to claim 1, wherein the line illumination light source can set an incident angle with respect to the substrate to an arbitrary angle at which an interference image or a diffraction image can be obtained by a line sensor camera. The line illumination light source is provided so as to be rotatable so that an incident angle with respect to the substrate can be arbitrarily set, and the transport means is provided so as to be able to reciprocate the substrate in a macro inspection region of the macro inspection unit, The control unit changes an incident angle of the light source for line illumination on the forward path or the return path of the substrate, and captures an interference image or a diffraction image on the forward path or the return path by a line camera sensor. The board | substrate inspection apparatus of description.

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