JP2005055207A - Inspection device having flattening function of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the end surface of a glass substrate for a display is warped or twisted because the glass substrate is heat-treated or a membrane of which the coefficient of expansion is different from that of a metal membrane is formed on the substrate heretofore and accurate inspection can not be performed. <P>SOLUTION: This inspection device having the function of flattening the glass substrate is equipped with a distance detecting sensor 26 for detecting the warp state of the glass substrate 7, a nozzle 22 for discharging the air from a compressor 27 and a control part 29 for opening and closing a valve 28 so as to discharge air from the nozzle 22 when the warpage of the glass substrate 7 is detected by the distance detecting sensor 26. The upward warped state (warp quantity) caused in the glass substrate 7 is grasped on the basis of a change in the distance data detected by the distance detecting sensor 26 and air is discharged from the nozzle 22 immediately before the leading end part of the warped glass substrate 7 reaches an imaging position to press the warpage of the glass substrate 7 to a substrate stage 9 by air pressure to flatten the glass substrate 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to improvements during inspection of large substrates, for example substrates for displays such as liquid crystal displays (LCDs) or plasma display panels (PDPs).
[0002]
[Prior art]
In general, flat panel displays (hereinafter simply referred to as displays) such as LCDs and PDPs, which achieve a reduction in size and weight and power consumption, are becoming popular in place of conventional display devices such as cathode ray tubes.
[0003]
These displays are often used in display units of televisions, personal computers, and the like, and there is a strong demand for large screens in televisions. With this demand, the size of the display substrate is increased, and the size of the display apparatus is also increased in the manufacturing apparatus.
[0004]
[Patent Document 1]
JP-A-8-274148
[Patent Document 2]
Japanese Patent Laid-Open No. 2000-21344
[Problems to be solved by the invention]
A glass substrate is mainly used as the display substrate as described above, and a large number of pixels, drive circuits, and the like are formed on the glass substrate through a plurality of manufacturing steps. These manufacturing processes include various inspection processes such as an appearance inspection and an electrical inspection in order to detect the presence or absence of a defective part.
[0007]
As this appearance inspection, there are a pattern inspection and a defect inspection in which a substrate surface is imaged using an image pickup device such as a CCD and an obtained image is observed. For such imaging, in order to obtain a high-resolution image using an optical system (barrel) equivalent to a microscope, the substrate surface must be accurately focused.
[0008]
Therefore, as the glass substrate becomes larger, it is important to flatten the glass substrate even during production. In other words, even if it is a flat glass substrate before manufacturing, heat treatment such as CVD during film formation or heat treatment such as annealing treatment has a significant effect on the glass substrate, and in particular, a metal film or the like is formed on the glass substrate. In such a case, even at room temperature, stress acts due to the difference in thermal expansion coefficient between the glass and the metal film, causing the glass substrate to be twisted or warped. Therefore, as the glass substrate becomes larger, warpage is more likely to occur, and the amount of warpage (warpage angle) becomes larger. In particular, the warp increases toward the end of the glass substrate.
[0009]
Usually, even if the glass substrate is enlarged, circuit elements and patterns are formed up to the vicinity of the end portion thereof, so even a warped portion must be inspected.
[0010]
For example, Patent Document 1 discloses a technique for pressing and fixing a substrate with a pressing member. Japanese Patent Application Laid-Open No. H10-228561 discloses a technique for fixing a substrate (wafer) by pressing it with a pressing pin.
[0011]
Both of these techniques have a structure in which the substrate is pressed down by mechanical parts to eliminate warping and twisting, and thus contact with the substrate, resulting in problems such as contamination. In addition, since the present invention targets a thin glass substrate as a substrate, when it is pressed with a protrusion or a pin as in References 1 and 2, stress is generated at that portion, and scratches and cracks are generated. There is a risk of damage. In particular, if a glass substrate is cracked, it is cracked during the manufacturing process. Therefore, the cracked glass substrate must be detected and disposed of at an early stage. Since this glass substrate is cracked from a small scratch, it is not preferable to fix it using a mechanical member.
[0012]
Accordingly, the present invention provides an inspection apparatus having a substrate flattening function capable of eliminating a lift due to warpage during substrate inspection and obtaining an appropriate inspection image when the substrate is lifted due to warping or twisting. The purpose is to provide.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention blows gas to the warped or twisted portion of the substrate existing in the inspection region, and corrects the warped or twisted portion of the substrate during the inspection period. An inspection apparatus having a function of planarizing a substrate to be performed is provided.
[0014]
In addition, a transport unit that transports the substrate, an imaging unit that is provided in the transport unit and captures the entire surface of the transported substrate and obtains an image to be used for inspection, along the imaging region of the image capturing unit, etc. A plurality of nozzles that are arranged at intervals and that discharge a gas and a warp detection unit that detects a warp state of the substrate from a change in the distance between the substrate and the transported substrate are conveyed by the warp detection unit. An inspection apparatus having a flattening function of a substrate for discharging the gas to the warped portion detected from the nozzle and flattening the warp when the warp of the substrate is detected.
[0015]
Furthermore, a transport unit that transports the substrate, an imaging unit that is provided in the transport unit and captures the entire surface of the transported substrate and obtains an image used for inspection, along the imaging region of the image capturing unit, etc. A plurality of nozzles that are arranged at intervals and discharge gas, a moving mechanism that can rotate the nozzle and move in parallel with the surface of the substrate, and a change in the distance between the substrate to be conveyed, A warp detection unit for detecting the warp state, a warp state of the warp portion detected by the warp detection unit, a material and a thickness of the substrate, a discharge pressure discharged from a nozzle for flattening the warp portion, and a discharge A reference table that stores an amount and a discharge direction in association with each other, and when the warp of the substrate conveyed by the warp detection unit is detected, the warp state is referred to the reference table to discharge gas. Pressure Calculates the discharge amount and discharge direction, and adjusting the nozzle to provide an inspection apparatus having a planarizing function of the substrate to flatten by ejecting a gas into the warp portion.
[0016]
The inspection apparatus having the flattening function of the substrate configured as described above sequentially detects the distance data to the substrate when the glass substrate adsorbed on the substrate stage is transported and passes under the distance detection sensor. And a control part grasps | ascertains the state (warp amount) of the curvature which arose in the glass substrate by the change of distance data. Immediately before the tip portion of the warped glass substrate reaches the imaging position of the inspection section, air is discharged, and the warped portion is pressed against the substrate stage by the pressure of the air to be flattened.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 shows an external configuration example of a substrate inspection apparatus according to the first embodiment of the present invention, and FIGS. 2 and 3 show an arrangement example and a configuration example of a substrate flattening unit in an inspection unit of the substrate inspection apparatus. FIG. Hereinafter, description will be given with reference to these drawings.
[0019]
This substrate inspection apparatus is roughly divided into a substrate carry-in unit 1, an apparatus main body (substrate transfer unit) 2, an inspection unit 3, a substrate carry-out unit 4, and substrate transfer robots 5 and 6.
[0020]
The substrate carry-in unit 1 receives the glass substrate 7 of the display held by suction on the transfer arm 8 of the substrate transfer robot 5 by the substrate stage 9. The upper surface (substrate mounting surface) of the substrate stage 9 is provided with a large number of air holes 10 and grooves 11 through which the transfer arm 8 enters during delivery. Further, suction pads 12 and 13 for sucking the glass substrate 7 are provided at both ends of the substrate stage 9 on the transport direction side.
[0021]
The substrate carry-in unit 1 holds the glass substrate 7 in a floating state by discharging compressed air from the air holes 10 on the substrate stage 9 while adsorbing the back end of the glass substrate 7 with the suction pads 12 and 13. Further, at both ends in front of the substrate stage 9, support portions 17 are provided that are movable along sliders 14 and 15 provided on both sides of the apparatus main body. The substrate carry-out unit 4 has the same configuration as the substrate carry-in unit 1, and the substrate transfer robot 6 has the same configuration as the substrate transfer robot 5.
[0022]
Further, the sliders 14 and 15 described above are provided on both sides of the apparatus main body 2, and two rails (grooves) 11 for moving the substrate stage 18 are provided on the inner side thereof, on the apparatus main body 2 (center in FIG. 1). Is provided with an inspection section 3. In the present embodiment, as the inspection unit 3, six imaging units 21a to 21f including an imaging unit including a lens barrel and an illuminating unit are arranged and fixed to the gate pole arm. An inspection image over the entire surface of the transported glass substrate 7 is captured. In these imaging units 21 (21a to 21f), the intersection (inspection area or imaging position) between the imaging optical axis and the illumination optical axis is adjusted so as to be positioned on the surface of the glass substrate 7 serving as a subject. The glass substrate is inspected (imaged) at the in-focus position of the intersection.
[0023]
In addition, a set of nozzles 22 (22a, 22b) are attached to the imaging units 21a to 21f by fixing brackets 23 so as to be equally spaced with respect to the imaging area of the glass substrate 7. These nozzles 22 discharge air (or gas) as will be described later. Among these, the nozzle 22a acts to flatten the warp and twist occurring on the front end side of the glass substrate 7, and the nozzle 22b is the warp and twist occurring on the rear end side of the glass substrate 7. Acts to flatten.
[0024]
In this embodiment, as shown in FIG. 3, the nozzles 22a and 22b are both at the surface (imaging surface) of the glass substrate or in the vicinity thereof, and are inclined at 30 ° back and forth with respect to the perpendicular perpendicular thereto. It is attached so as to discharge (air or gas). Of course, the attachment angle (discharge angle) is not limited and can be changed as appropriate, and the discharge is performed so as to efficiently suppress the warp, and preferably the direction perpendicular to the warp direction is desirable.
[0025]
In addition, a curved slit is formed in the fixing metal 23 and is fixed by at least two adjusting screws 24. When these adjustment screws 24 are loosened and moved along the slits of the fixture 23, the discharge direction of the nozzles 22a and 22b can be varied, and the discharge direction of the nozzles 22a and 22b can be adjusted in accordance with the thickness of the substrate. Can do.
[0026]
In the following description, air will be described as an example of gas. In addition, an inert gas such as nitrogen gas or argon gas is suitable as the gas. As a supply source, a compressor is used for air, and a cylinder or the like is used for gas. The nozzle 22 has an air passage formed in the nozzle body, and a discharge port narrower than the air passage is opened at the nozzle tip. Also, for example, a splitter similar to that used in a valve may be provided in the air passage, and the nozzle tip may be moved back and forth to vary the width of the passage and adjust the discharge amount to be discharged. . The discharge direction, the discharge pressure, and the discharge amount can be changed by the back and forth movement of the fixing bracket 23 and the nozzle tip.
[0027]
Each of the imaging units 21a to 21f is provided with a distance detection sensor 26 that detects the distance to the glass substrate 7 in a non-contact manner using a laser or the like. This distance detection sensor 26 functions as a warp detection unit that detects the warpage state of the glass substrate 7, that is, the amount of warpage (warpage angle) by continuously detecting the distance to the glass substrate 7 to be conveyed.
[0028]
FIG. 4 shows and describes the block configuration of the substrate flattening portion.
The substrate flattening unit includes a distance detection sensor 26 that detects a warped state of the glass substrate 7, a nozzle 22 (22a, 22b) that discharges air, a compressor 27 that compresses and sends air to the nozzle 22, and a nozzle And a control unit 29 that opens and closes the valve 28 so that air is discharged from the nozzle 22 when warpage is detected by the distance detection sensor 26. The
[0029]
The operation of the substrate flattening portion configured as described above will be described.
[0030]
As shown in FIG. 5A, when the glass substrate 7 that is air levitation-held on the substrate stage 18 is transported and passes below the distance detection sensor 26, the distance detection sensor 26 sequentially detects the distance data. To the control unit 29. The control unit 29 grasps the state of warping (the amount of warping and the warping direction) generated in the glass substrate 7 due to the change in the distance data.
[0031]
As shown in FIG. 5B, the valve 28 is opened by the control of the control unit 29 immediately before the tip of the glass substrate 7 where the warp has occurred reaches the intersection of the optical axes, that is, the imaging position. Air is discharged, and the warped portion is pressed against the substrate stage 9 by the pressure of the air to be flattened. After the imaging is finished, the air discharge is stopped. That is, the glass substrate may be flattened during the inspection period (during imaging). When air is discharged, air may be continuously discharged while the warped portion passes through the imaging position, or air is discharged only from the time immediately before the warped portion reaches the imaging position until imaging. May be. Therefore, if the imaging time is short, the air may not be ejected intermittently and may be intermittently ejected in pulses. In addition, when flattening the warp, the pressure of the air to be discharged and the discharge amount are obtained in advance so that the glass substrate 7 and the mounting surface of the substrate stage 9 do not come into contact with each other. Adjustment is performed based on the obtained numerical value.
[0032]
As described above, according to the present embodiment, it is possible to capture a focused inspection image by flattening the warpage generated in the glass substrate during the substrate inspection, and the obtained inspection image is more appropriate. Inspection judgment can be realized.
[0033]
Next, a second embodiment will be described.
In general, warpage and twist generated in a substrate used in a display, for example, a glass substrate, do not occur in a uniform warp state (twist condition). This differs depending on various forms, such as the material and thickness of the glass substrate, the glass substrate on which the metal thin film is formed, and the heat treatment. In the present embodiment, flattening is achieved by discharging air that is appropriate for the warped state generated in the glass substrate. In addition, the board | substrate planarization part in this embodiment is demonstrated as what is mounted in the board | substrate inspection apparatus demonstrated in 1st Embodiment.
[0034]
FIG. 6 is a diagram illustrating a configuration example of the substrate planarization unit in the second embodiment.
[0035]
This substrate flattening section has a moving mechanism 30 in which the nozzle 31 rotates and translates, and has the function of combining the nozzles 22a and 22b described above with one nozzle. The nozzle 31 is attached to a rotation gear 33 that is rotatably provided on the nozzle base portion 32. The nozzle base portion 32 is provided so as to be movable along a horizontal groove 34 formed in the main body of the imaging unit 21. Further, on the upper side of the nozzle base portion 32, a parallel movement gear portion 35 in which several gears are formed is provided.
[0036]
In order to rotate and translate the nozzle 31, a worm gear 37 that meshes with either the rotation gear 33 or the parallel movement gear portion 35, a motor 38 that rotates the worm gear 37, and the motor 38 are fixed. In addition, a drive mechanism configured with a motor base portion 40 movable along the vertical groove 39 is provided.
[0037]
In FIG. 6, when the motor base 40 is in the A position, the worm gear 37 and the rotating gear 33 are in mesh with each other, and the nozzle 31 can be rotated to change the discharge direction. Further, when the motor base portion 40 is in the B position, the worm gear 37 and the parallel movement gear portion 35 are engaged with each other, and the nozzle 31 can be translated. Switching between the A position and the B position in the motor base 40 can be moved using a magnet or the like (not shown).
[0038]
Further, when the nozzle base portion 32 is at the C position, the warp generated at the front end portion of the glass substrate 7 is flattened. When the nozzle base portion 32 is at the D position, it occurs at the rear end portion of the glass substrate 7. Plan to flatten against warping.
[0039]
FIG. 7 shows and describes the block configuration of the substrate planarization unit.
[0040]
Here, in the constituent parts of this embodiment, the same parts as those shown in FIG. 4 are given the same reference numerals.
[0041]
The substrate flattening unit includes a distance detection sensor 26 that detects a warped state of the glass substrate 7, a nozzle 31 that discharges air, a compressor 27 that compresses and sends air to the nozzle 31, and a nozzle 31 and a compressor 27. A variable valve 41 provided in the middle of the pipe and capable of adjusting the flow rate passing therethrough, a reference table 42 that stores data for flattening the warp in advance, and a warp state (warp amount) detected by the distance detection sensor 26. In comparison with the reference table 42, the pressure, discharge amount and discharge direction of the air to be discharged are obtained, the nozzle 31 is rotated and translated by the moving mechanism 30, and then air is discharged to the warped portion to achieve flattening. It is comprised with the control part 29. FIG.
[0042]
The reference data stored in the reference table 42 is empirically obtained and stored in advance. For example, the reference data is necessary for flattening the warped portion according to the material, thickness, and warpage state (warpage amount) of the substrate. The air pressure, the discharge amount, and the discharge direction are obtained and tabulated.
[0043]
The operation of the substrate flattening portion configured as described above will be described.
First, the nozzle base portion 32 is arranged on the C position side. When the glass substrate 7 held by air levitation is transferred to the substrate stage 9 and passes below the distance detection sensor 26, the distance detection sensor 26 sequentially detects the distance data and sends it to the control unit 29. The control unit 29 grasps the warped state (warpage amount) generated in the glass substrate 7 due to the change in the distance data.
[0044]
And the control part 29 reads the reference table 42 applicable from the reference table divided according to the presence or absence of the material of glass substrate, thickness, a metal film, etc. which were preset before the inspection, and the discharge pressure and the discharge amount in the warped state And determine the discharge direction. The control unit 29 drives the moving mechanism 30 based on these determination items to rotate and translate the nozzle 31. Immediately before the warped portion of the glass substrate 7 to be conveyed arrives at the imaging position, the control unit 29 controls to open the appropriate amount of the variable valve 41 and discharge the air to the warped portion for flattening, and then inspect by the imaging unit. An image is taken. In addition, when flattening the warpage, the glass substrate 7 and the mounting surface of the substrate stage 9 are discharged so as not to contact each other.
[0045]
Thereafter, the moving mechanism 30 is driven to translate the nozzle base portion 32 and rotate it in the same direction as the valve 22b shown in FIG. 2 to cope with the warp occurring at the rear end portion of the glass substrate 7. It can be so.
[0046]
According to the second embodiment described above, the warpage state of the glass substrate is detected, and the discharge pressure, the discharge amount, and the discharge direction in the air discharged from the nozzle can be obtained in correspondence with the warpage state. . Further, not only the material and thickness of the glass substrate but also the warp can be appropriately eliminated at the time of imaging even when a metal film is formed on the glass substrate. In the present embodiment, an example is described in which one movable nozzle is used. However, the nozzles 22a and 22b of the first embodiment described above may be replaced with movable nozzles.
[0047]
Next, a third embodiment will be described.
The nozzles of the first and second embodiments described above are in a state in which a plurality of points are arranged. However, in this embodiment, the nozzle is modified so as to discharge air in a slit shape.
[0048]
As shown in FIG. 8A, the outer shape of the nozzle 51 is arranged between the imaging units 21 in a skirt shape. As shown in FIGS. 8B and 8C, the nozzle 51 has a narrow inner width and forms a discharge port in a slit shape. By setting it as such a shape, a warp rise can be suppressed from the point by the linear force, and it can planarize.
[0049]
Next, a fourth embodiment will be described.
In the first and second embodiments described above, high-pressure air is discharged to the warped portion in order to flatten the warpage of the glass substrate by the nozzle. In some cases, vibration is generated in a warped portion where air is blown, and this vibration may be transmitted to the glass substrate 7 in a lifted state.
[0050]
Therefore, in the present embodiment, as shown in FIG. 9, in the substrate stage 9, the central portion of the substrate placement surface is lowered one step, and the suction groove 52 is formed in this portion. One or more suction ports 53 are provided at the bottom of the suction groove 52. The air holes 10 described above are formed in the substrate mounting surfaces on both sides of the suction groove 52, the compressed air is discharged from the air holes 10 to float the glass substrate 7, and the glass substrate 7 is centered by the suction groove 52. Adsorb part. Further, as in the above-described embodiment, the end portions of the glass substrate 7 are sucked by the suction pads 12 and 13.
[0051]
According to the fourth embodiment described above, the central portion of the glass substrate 7 is adsorbed and held floating, so that vibration generated by air blown to flatten the warpage is prevented. can do.
[0052]
【The invention's effect】
As described above in detail, according to the present invention, when the substrate is lifted due to warping or twisting, it is possible to eliminate the lifting due to warpage during substrate inspection and to obtain an appropriate inspection image. It is possible to provide an inspection apparatus having a function of making the data.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an external configuration example of a substrate inspection apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating an arrangement example of a substrate flattening unit in the inspection unit according to the first embodiment.
FIG. 3 is a diagram illustrating a configuration example of a substrate flattening unit in the inspection unit according to the first embodiment.
FIG. 4 is a diagram showing a block configuration of a substrate flattening unit in the inspection unit of the first embodiment.
FIG. 5 is a diagram for explaining the operation of the substrate planarization unit of the first embodiment.
FIG. 6 is a diagram illustrating a configuration example of a substrate flattening unit according to the second embodiment.
7 is a diagram illustrating a block configuration of a substrate flattening unit in an inspection unit according to a second embodiment. FIG. 8 is a diagram illustrating a shape of a nozzle according to a third embodiment.
FIG. 9 is a diagram illustrating a configuration example of a substrate stage of a substrate planarization unit according to a fourth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Substrate carrying-in part, 2 ... Apparatus main body (substrate conveyance part), 3 ... Inspection part, 4 ... Substrate carrying-out part, 5, 6 ... Substrate conveyance robot, 7 ... Glass substrate, 8 ... Conveyance arm, 9 ... Substrate stage, DESCRIPTION OF SYMBOLS 10 ... Air hole, 11 ... Groove (rail), 12, 13 ... Suction pad, 14, 15 ... Slider, 17 ... Support part, 21 (21a-21f) ... Imaging unit, 22 (22a, 22b) ... Nozzle, 23 …securing bracket.

Claims (7)

An inspection apparatus having a flattening function of a substrate for performing an inspection by blowing a gas to a warped portion or a twisted portion of a substrate existing in an inspection region and correcting the warped or twisted portion of the substrate during an inspection period. A transport unit for transporting the substrate;
An imaging unit that is provided in the transport unit and captures the entire surface of the substrate to be transported to obtain an image used for inspection;
A plurality of nozzles that are arranged at equal intervals along the imaging region of the imaging unit and discharge gas,
A warp detection unit for detecting a warp state of the substrate from a change in distance from the substrate to be transported;
An inspection apparatus having a substrate flattening function for discharging a gas to a warped portion detected from the nozzle and flattening the warp when the warp of the substrate conveyed by the warp detection unit is detected. The inspection apparatus having a substrate flattening function according to claim 2, wherein the nozzle discharges from a direction perpendicular to a direction of warpage generated in the substrate. The said nozzle is comprised with the 1st nozzle which planarizes the curvature of the front end of the said board | substrate conveyed, and the 2nd nozzle which planarizes the curvature of the rear end of the said board | substrate conveyed. An inspection apparatus having a flattening function of the substrate according to 1. The transport unit includes a substrate stage on which the substrate can be placed and moved,
On the substrate mounting surface of the substrate stage, a plurality of air holes for discharging gas,
A suction pad pair for sucking the substrate at both ends of the substrate stage in the transport direction;
The inspection apparatus having a substrate flattening function according to claim 2, wherein the substrate is held while floating. A suction groove provided with a suction port for sucking the gas discharged from the air hole at the center of the substrate placement surface of the substrate stage;
The substrate flattening function according to claim 2, wherein the substrate is lifted by the gas discharged from the air holes and sucked and held by a suction groove to prevent the gas discharged from the nozzle from vibrating to the substrate. Inspection device having A transport unit for transporting the substrate;
An imaging unit that is provided in the transport unit and captures the entire surface of the substrate to be transported to obtain an image used for inspection;
A plurality of nozzles that are arranged at equal intervals along the imaging region of the imaging unit and discharge gas,
A moving mechanism capable of rotating the nozzle and moving in parallel with the surface of the substrate;
From a change in distance from the substrate to be transported, a warp detection unit that detects a warp state of the substrate,
A reference for storing the warpage state of the warped portion detected by the warpage detecting unit, the material and thickness of the substrate, and the discharge pressure, discharge amount, and discharge direction discharged from the nozzle that flattens the warped portion. Table,
Comprising
When the warp of the substrate conveyed by the warp detection unit is detected, the warp state is referred to the reference table, the pressure of the gas to be discharged, the discharge amount and the discharge direction are calculated, and the nozzle is adjusted. And an inspection apparatus having a flattening function of the substrate for discharging and flattening the gas to the warped portion.

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