JP2005156416A - Method and apparatus for inspecting glass substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect flaws on the periphery of a glass substrate, using an easy method or a simple apparatus. <P>SOLUTION: A light-projecting system 10 projects strip-shaped inspection light with a cross section which is long in the Y-direction, obliquely on the periphery including edge sections of the glass substrate 1. A condenser lens 21 of a light-receiving system 20 condenses reflected light and scattered light from the rear face of the glass substrate 1, and a slit plate 22 blocks the scattered light and makes the reflected light to pass therethrough. An imaging lens 23 provides image of the light passing through the slit plate 22 onto a light receiving surface of a CCD line sensor 24, and the CCD line sensor 24 outputs a detection signal which corresponds to the intensity of the light received by the light-receiving surface, to a detection device 40. Although the intensity of the reflected light hardly varies, even when a foreign substance is attached to the rear face of the glass substrate 1, when a flaw exists in the rear face of the glass substrate 1, a portion of the light reaching the glass substrate 1 is scattered, and the intensity of the reflected light is lowered. The detection device 40 detects flaws in the rear face of the glass substrate 1, based on the position of a variation point in the detection signal from the CCD line sensor 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a glass substrate inspection method and inspection apparatus used for manufacturing display panels and the like, and more particularly to a glass substrate inspection method and inspection apparatus suitable for inspecting scratches on the periphery of a glass substrate.

  Manufacture of TFT (Thin Film Transistor) substrates, color filter substrates, plasma display panel substrates, organic EL (Electroluminescence) display panel substrates, etc. for liquid crystal display devices used as display panels on glass substrates using photolithography technology This is done by forming a pattern. At that time, if a defect such as a scratch or a foreign substance exists on the surface of the glass substrate, the pattern is not formed well, which causes a defect. For this reason, conventionally, inspection of defects such as scratches and foreign matters on the surface of the glass substrate has been performed using a defect inspection apparatus.

The defect inspection apparatus irradiates a glass substrate with inspection light such as a laser beam and receives reflected light or scattered light from the front or back surface of the glass substrate to detect defects such as scratches and foreign matter. A technique described in Patent Document 1 is known as a method for determining whether a detected defect is a scratch or a foreign substance in an inspection of a glass substrate using a defect inspection apparatus. Moreover, the technique of patent document 2 is known as a method of identifying whether the detected defect exists in the front surface or the back surface of a glass substrate.
Japanese Patent Laid-Open No. 9-257642 JP-A-9-258197

  In the peripheral part where the pattern of the glass substrate is not formed, the adhesion of foreign matters is not a problem. On the other hand, scratches such as chips are easily generated in the peripheral portion of the glass substrate, and if there is a scratch in the peripheral portion of the glass substrate, the glass substrate may be damaged when subjected to thermal shock or physical shock. For this reason, there is a demand to independently inspect only the scratches on the peripheral portion of the glass substrate, and such a demand has become stronger with the recent increase in size of the glass substrate.

  However, the conventional defect inspection apparatus cannot detect the scratches on the glass substrate separately from the foreign matter, and performs a process as described in Patent Document 1 in order to determine whether the detected defects are scratches. Had to be done. Therefore, there is a problem that the apparatus becomes complicated and the inspection takes time.

  The subject of this invention is detecting the damage | wound of a glass substrate, without detecting the foreign material adhering to the glass substrate. Moreover, the subject of this invention is test | inspecting the damage | wound of the peripheral part of a glass substrate with a simple method or apparatus.

  The glass substrate inspection method of the present invention obliquely irradiates the surface of the glass substrate with inspection light comprising a parallel light bundle, blocks scattered light from the back surface of the glass substrate, and reflects reflected light from the back surface of the glass substrate. The scratches on the back surface of the glass substrate are detected from the received light and the intensity of the received reflected light.

  The glass substrate inspection apparatus of the present invention includes a light source and a focusing unit that focuses the light generated by the light source into a parallel light bundle, and the inspection light focused by the focusing unit is obliquely directed to the surface of the glass substrate. A light receiving system having a light projecting system for irradiating, a light shielding means for blocking scattered light from the back surface of the glass substrate and allowing reflected light from the back surface of the glass substrate to pass, and a light receiving means for receiving the light passing through the light shielding means And detecting means for detecting a scratch on the back surface of the glass substrate from the intensity of light received by the light receiving means.

  Part of the inspection light irradiated obliquely onto the surface of the glass substrate is refracted into the glass substrate, reaches the back surface of the glass substrate, and is reflected by the back surface of the glass substrate. Even if foreign matter adheres to the back surface of the glass substrate, the intensity of the reflected light from the back surface of the glass substrate hardly changes. On the other hand, if there is a scratch on the back surface of the glass substrate, a part of the light reaching the back surface of the glass substrate is scattered, and the intensity of reflected light from the back surface of the glass substrate is reduced. The scattered light from the back surface of the glass substrate is blocked, the reflected light from the back surface of the glass substrate is received, and scratches on the back surface of the glass substrate are detected from the intensity of the received reflected light.

  Further, the glass substrate inspection method of the present invention irradiates the peripheral portion including the end portion of the glass substrate with inspection light having a strip-like cross section, and from the position of the intensity change point of the received reflected light, the peripheral portion of the glass substrate It is intended to detect flaws. Further, in the glass substrate inspection apparatus of the present invention, the focusing means focuses the light generated by the light source into a parallel light bundle having a cross section in the cross section, and the light projecting system includes a peripheral portion including the end of the glass substrate. The detection means detects scratches on the periphery of the glass substrate from the position of the change point of the intensity of the light received by the light receiving means.

  When the inspection light having a strip-like cross section is irradiated to the peripheral portion including the end portion of the glass substrate, since the reflection is not performed outside the glass substrate, the intensity of the reflected light changes at the position of the end portion of the glass substrate. If there is a scratch on the back surface of the glass substrate, a part of the light reaching the back surface of the glass substrate is scattered, and the changing point of the intensity of the reflected light moves. A scratch on the periphery of the glass substrate is detected from the position of the change point of the intensity of the reflected light.

  According to the present invention, the scattered light from the back surface of the glass substrate is blocked, and the reflected light from the back surface of the glass substrate is received, so that no foreign matter on the back surface of the glass substrate is detected. Scratches can be detected. Further, by irradiating the surface of the glass substrate with inspection light composed of parallel light beams obliquely, scattered light from the back surface of the glass substrate can be easily blocked using a light shielding means such as a slit plate.

  Furthermore, by using a strip-shaped inspection light and detecting scratches on the periphery of the glass substrate from the position of the reflected light intensity change point, the scratches on the periphery of the glass substrate are inspected with a simple method or apparatus. can do.

  FIG. 1 is a diagram showing a schematic configuration of a glass substrate inspection apparatus according to an embodiment of the present invention. The inspection device includes the chuck 2, the light projecting system 10, the light receiving system 20, the moving mechanism 30, and the detection device 40. FIG. 2 is a perspective view showing a light projecting system and a light receiving system of the glass substrate inspection apparatus according to the embodiment of the present invention. Note that the chuck 2, the moving mechanism 30, and the detection device 40 are omitted in FIG.

  The inspection by the inspection apparatus of this embodiment is performed separately from the inspection by the conventional defect inspection apparatus. When both are implemented, the inspection by the conventional defect inspection apparatus is performed on the central portion excluding the peripheral portion of the glass substrate while supporting the peripheral portion of the glass substrate. On the other hand, the inspection by the inspection apparatus of the present embodiment is performed on the peripheral portion including the end portion of the glass substrate 1 while supporting the central portion of the glass substrate.

  In FIG. 1, a chuck 2 fixes the central portion of a glass substrate 1 by vacuum suction or the like. A light projecting system 10 and a light receiving system 20 are arranged above the glass substrate 1 fixed to the chuck 2.

  The light projecting system 10 includes a laser light source 11 and a focusing lens 12. The laser light source 11 generates laser light serving as inspection light. The converging lens 12 condenses the laser light generated from the laser light source 11 into a strip-shaped parallel light beam having a long cross section in the Y direction. The light projecting system 10 irradiates the peripheral portion including the end portion of the glass substrate 1 obliquely at an angle α with a strip-shaped inspection light having a cross section emitted from the focusing lens 12 and extending in the Y direction.

  A part of the inspection light irradiated obliquely onto the surface of the glass substrate 1 is refracted into the glass substrate 1 to reach the back surface of the glass substrate 1 and reflected by the back surface of the glass substrate 1. The reflected light reflected by the back surface of the glass substrate 1 passes through the inside of the glass substrate 1 and is emitted obliquely from the surface of the glass substrate 1 to the outside at the same angle α as the incident angle. Moreover, when there is a scratch on the back surface of the glass substrate 1, a part of the light reaching the back surface of the glass substrate 1 is scattered, and scattered light is generated. The generated scattered light passes through the inside of the glass substrate 1 and is emitted from the surface of the glass substrate 1 to the outside at an arbitrary angle.

  The light receiving system 20 includes a condenser lens 21, a slit plate 22, an imaging lens 23, and a CCD line sensor 24. The condensing lens 21 condenses the reflected light and scattered light emitted from the surface of the glass substrate 1. The slit plate 22 has a strip-like slit that is long in the Y direction, and blocks the scattered light out of the reflected light and scattered light collected by the condenser lens 21 and allows the reflected light to pass. The imaging lens 23 forms an image of the light that has passed through the slit plate 22 on the light receiving surface of the CCD line sensor 24. The CCD line sensor 24 has a plurality of CCDs arranged in the Y direction of the light receiving surface, and outputs a detection signal corresponding to the intensity of light received by the light receiving surface to the detection device 40.

  The moving mechanism 30 includes an XY moving mechanism and a rotating mechanism, and moves or rotates both in the X direction or the Y direction while keeping the relative position of the light projecting system 10 and the light receiving system 20 constant. By moving the light projecting system 10 and the light receiving system 20 in the X direction, in FIG. 2, the inspection light irradiated from the light projecting system 10 moves in the X direction around the peripheral portion including the end 1a of the glass substrate 1, The peripheral part including the end part 1a of the glass substrate 1 is inspected. Subsequently, after the light projecting system 10 and the light receiving system 20 are moved stepwise in the Y direction, the light projecting system 10 and the light receiving system 20 are moved in the reverse direction in the X direction, thereby including the end 1c of the glass substrate 1. Peripheral inspection is performed. After rotating the light projecting system 10 and the light receiving system 20 by 90 degrees, the peripheral portion including the end portions 1b and 1d of the glass substrate 1 is inspected by switching the X direction and the Y direction and performing the same operation. .

  Instead of moving and rotating the light projecting system 10 and the light receiving system 20 using the moving mechanism 30, the glass substrate 1 may be moved and rotated using an XYθ stage on which the chuck 2 is mounted.

  The detection device 40 detects a scratch on the back surface of the glass substrate 1 from the detection signal of the CCD line sensor 24 as follows. FIG. 3A is a perspective view of a peripheral portion including an end portion of the glass substrate, FIG. 3B is a cross-sectional view thereof, and FIG. ) Is a diagram showing a detection signal. 4A is a perspective view of a peripheral portion including the end portion of the glass substrate, FIG. 4B is a cross-sectional view thereof, and FIG. FIG. 4 is a diagram showing detection signals.

  When the inspection light is irradiated as shown in FIG. 3A, the intensity of the reflected light from the back surface of the glass substrate 1 hardly changes even if the foreign material 3 adheres to the peripheral portion of the back surface of the glass substrate 1. Since reflection is not performed outside the glass substrate 1, the detection signal indicating the intensity of the reflected light changes at the end position of the glass substrate 1 as shown in FIGS. 3 (b) and 3 (c).

  On the other hand, when there is a chip 4 at the end of the back surface of the glass substrate 1, when the inspection light is irradiated as shown in FIG. 4A, a part of the inspection light reaching the back surface of the glass substrate 1 is chipped 4. It is scattered in the part. Therefore, as shown in FIGS. 4B and 4C, the detection signal indicating the intensity of the reflected light changes at the position of the chip 4 on the glass substrate 1. The detection device 40 detects the chip 4 at the end of the glass substrate 1 from the position of the change point of the detection signal of the CCD line sensor 24, that is, the position of the change point of the intensity of the reflected light.

  Furthermore, even when there are other scratches such as scratches on the back surface of the glass substrate 1, a part of the inspection light reaching the back surface of the glass substrate 1 is scattered by these scratches, so that the detection signal of the CCD line sensor 24 Other scratches on the back surface of the glass substrate 1 can be detected from the position of the change point.

  According to the embodiment described above, the scattered light from the back surface of the glass substrate is blocked, and the reflected light from the back surface of the glass substrate is received, so that the glass is not detected on the back surface of the glass substrate. Scratches on the back surface of the substrate can be detected. Moreover, by irradiating the surface of the glass substrate obliquely with the inspection light composed of parallel light beams, the scattered light from the back surface of the glass substrate can be easily blocked using the slit plate 22.

  In addition, by using a strip-shaped inspection light and detecting scratches on the periphery of the glass substrate from the position of the reflected light intensity change point, the scratches on the periphery of the glass substrate are inspected with a simple procedure or device. can do.

It is a figure which shows schematic structure of the inspection apparatus of the glass substrate by one embodiment of this invention. It is a perspective view which shows the light projection system and light reception system of the inspection apparatus of the glass substrate by one embodiment of this invention. FIG. 3A is a perspective view of a peripheral portion including an end portion of the glass substrate, FIG. 3B is a cross-sectional view thereof, and FIG. ) Is a diagram showing a detection signal. FIG. 4A is a perspective view of a peripheral portion including the end of the glass substrate, FIG. 4B is a cross-sectional view thereof, and FIG. It is a figure which shows a signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Chuck 10 Light projection system 11 Laser light source 12 Condensing lens 20 Light receiving system 21 Condensing lens 22 Slit plate 23 Imaging lens 24 CCD line sensor 30 Moving mechanism 40 Detection apparatus

Claims (4)

Irradiate the surface of the glass substrate obliquely with inspection light consisting of parallel light bundles,
Blocks scattered light from the back side of the glass substrate, receives reflected light from the back side of the glass substrate,
A method for inspecting a glass substrate, comprising detecting a scratch on the back surface of the glass substrate from the intensity of received reflected light. Irradiate the periphery including the edge of the glass substrate with a strip-shaped inspection light,
The method for inspecting a glass substrate according to claim 1, wherein a flaw on the periphery of the glass substrate is detected from the position of the change point of the intensity of the received reflected light. A light source and a light projecting system that obliquely irradiates the surface of the glass substrate with the inspection light focused by the focusing means, the light source and a focusing means for focusing the light generated by the light source into a parallel beam bundle;
A light receiving system having a light shielding means for blocking scattered light from the back surface of the glass substrate and allowing reflected light from the back surface of the glass substrate to pass through, and a light receiving means for receiving the light that has passed through the light shielding means;
An inspection apparatus for a glass substrate, comprising: detection means for detecting scratches on the back surface of the glass substrate from the intensity of light received by the light receiving means. The focusing means focuses the light generated by the light source into a parallel light beam having a strip-like cross section,
The light projecting system irradiates the peripheral part including the end of the glass substrate with inspection light,
The said detection means detects the damage | wound of the peripheral part of a glass substrate from the position of the change point of the intensity | strength of the light which the said light-receiving means received, The inspection apparatus of the glass substrate of Claim 3 characterized by the above-mentioned.

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