JP2008076137A - Substrate inspection device and its inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate inspection device and its inspection method of high detection accuracy for flaw or foreign matter. <P>SOLUTION: In this substrate inspection device for inspecting with one surface of a translucent substrate as an inspection surface, a lighting system is disposed on a plane including the inspection surface while an imaging device is disposed in the direction of the normal of the inspection surface. This allows irradiation of only the inspection surface with illumination light substantially parallel to the inspection surface to allow detection of only foreign matter or flaw existing on the inspection surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate inspection apparatus and inspection method, and more particularly to a substrate inspection apparatus and inspection method for inspecting a surface of a light-transmitting substrate.

In a manufacturing process of an electro-optical device such as a liquid crystal panel formed of a light-transmitting substrate such as glass or quartz, an inspection device for inspecting the adhesion of foreign matters or the presence of scratches on the substrate surface is used. The inspection device is configured to include an imaging device and an illumination device, and recognizes the presence of a foreign object or a flaw by image processing by illuminating and imaging the substrate in a reflective or transmissive manner. This is disclosed in Japanese Patent No. 305503.
JP 2001-305503 A

  In general, in the case of inspecting the surface of a substrate having translucency, the illumination is on the same side as the imaging device with respect to the substrate, the transmitted illumination disposed at a position facing the imaging device across the substrate, In addition, coaxial epi-illumination disposed on the same axis as the optical axis of the imaging device is used.

  However, when transmission illumination or coaxial epi-illumination is used for illumination, since the substrate has translucency, foreign matter and scratches on the surface opposite to the surface to be inspected that the substrate is to be inspected are It will be reflected in the acquired image. In addition, for example, a collet that sucks and holds the substrate, a device existing in the background, or the like is reflected in the acquired image of the imaging device.

  In this way, if there is an unnecessary object in the acquired image, for example, a foreign object present on a surface that is not the surface to be inspected will be misrecognized as being present on the surface to be inspected, and the substrate should be a non-defective product. There is a problem that it will be judged as bad.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate inspection apparatus and inspection method with high detection accuracy of scratches or foreign matter.

  A substrate inspection apparatus according to the present invention is a substrate inspection device that inspects one surface of a light-transmitting substrate as a surface to be inspected, the imaging device disposed opposite to the surface to be inspected, and the object to be inspected. And an illuminating device disposed on a plane including the inspection surface.

  The substrate inspection method of the present invention is a substrate inspection method for inspecting one surface of a light-transmitting substrate as a surface to be inspected, wherein the light source is disposed on a plane including the surface to be inspected. The surface to be inspected is irradiated, and the surface to be inspected is imaged by an imaging device arranged to face the surface to be inspected.

  According to such a configuration of the present invention, the illumination light is incident substantially parallel to the surface to be inspected and is not irradiated on surfaces other than the surface to be inspected. Therefore, even if there are foreign objects or scratches on the surface other than the surface to be inspected, they do not appear in the image acquired by the imaging apparatus. Therefore, it is possible to recognize only foreign matter and scratches existing on the surface to be inspected of the light-transmitting substrate, and it is possible to eliminate erroneous detection and improve the detection accuracy of the scratches or foreign matter.

  Moreover, it is preferable that this invention comprises the light-shielding means which covers the surface except the said to-be-inspected surface of the said board | substrate.

  According to such a configuration, stray light generated in the illumination device and ambient environmental light do not enter the surface except the surface to be inspected. Therefore, the illumination light is more reliably irradiated only on the surface to be inspected, and it becomes possible to further improve the detection accuracy of a scratch or a foreign object.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the present invention is applied to a substrate inspection apparatus used in a manufacturing process of a transmissive liquid crystal display panel. In each drawing used for the following description, the scale is different for each member in order to make each member a size that can be recognized on the drawing. FIG. 1 is a perspective view showing a configuration of a liquid crystal display panel. FIG. 2 is a plan view for explaining the mother substrate. FIG. 3 is a schematic top view illustrating the configuration of the dustproof substrate sticking apparatus. FIG. 4 is a schematic configuration diagram illustrating the configuration of the substrate inspection apparatus. FIG. 5 is an explanatory diagram showing a method for detecting foreign matter and scratches.

  As shown in FIG. 1, a liquid crystal display panel 1 that is an electro-optical device includes a liquid crystal between a TFT array substrate 10 and a counter substrate 20 that are a pair of substrates each formed of a transparent material such as glass and quartz. It is a transmissive liquid crystal device configured by enclosing a layer. The liquid crystal display panel 1 is used as a light valve of a projection display device such as a projector. The liquid crystal display panel 1 transmits light by changing the orientation and order of the molecular assembly of the liquid crystal layer by changing the voltage level between the TFT array substrate 10 and the counter substrate 20 in the image display region 10a. Modulates light to enable gradation display. The TFT array substrate 10 and the counter substrate 20 have rectangular shapes of different sizes, and the counter substrate 20 is formed smaller than the TFT array substrate 10. An external circuit connection terminal (not shown) is provided in the vicinity of one side of the surface on the counter substrate 20 side of the TFT array substrate 10 of the liquid crystal display panel 1, and a flexible printed circuit board (on the external circuit connection terminal) Hereinafter, an FPC (referred to as “Flexible Printed Circuit”) 13 is mounted. The FPC 13 is parallel to the surface of the TFT array substrate 10 on the counter substrate 20 side, and extends outward from the side where the external circuit connection terminals are provided. For example, when the liquid crystal display panel 1 is used for a projection display device, the liquid crystal display panel 1 is connected to a control device of the projection display device via the FPC 13 and receives image signals and various drive signals transmitted from the control device. Based on this, an image is displayed. Further, dust-proof substrates 11 and 12 are attached to the surfaces of the TFT array substrate 10 and the counter substrate 20 constituting the liquid crystal display panel 1 on the opposite side to the liquid crystal layer, respectively. The dustproof substrates 11 and 12 are each made of translucent glass, quartz, or the like, and are fixed by a thermosetting adhesive.

  In the present embodiment, the liquid crystal display panel 1 is formed in a manufacturing process in a state where a plurality of liquid crystal display panels 1 are arranged on a single mother substrate 15 as shown in FIG. That is, after a laminated structure to be the TFT array substrate 10 is formed on the mother substrate 15, the counter substrate 20 is pasted to seal the liquid crystal, and the dustproof substrates 11 and 12 are pasted, and then the liquid crystal display panel 1 is cut into individual pieces.

  Below, the dust-proof board | substrate sticking process which is a manufacturing process in which the board | substrate inspection apparatus which concerns on this embodiment is used is demonstrated. In the dust-proof substrate attaching step described below, the dust-proof substrate 11 is attached to each of the plurality of counter substrates 20 attached on the mother substrate 15, and the dust-proof substrate shown in FIG. A substrate sticking device 30 is used.

  The dustproof substrate sticking device 30 is mainly composed of a mother substrate transport device 100 and a dustproof substrate sorting device 200.

  The dustproof substrate sorting apparatus 200 includes a transfer robot 201, a surface inspection apparatus 250, a carry-in apparatus 280, and an NG stocker 290.

  The carry-in device 280 is a device that carries the pallet 281 on which the plurality of dust-proof substrates 12 are placed into the dust-proof substrate sorting device 200.

  The transfer robot 201 is a horizontal articulated robot, a so-called SCARA robot, and is a device that holds and transports the dust-proof substrate 12 on the pallet 281 carried by the carry-in device 280 by the suction collet 210. As shown in FIG. 4, the adsorption collet 210 adsorbs the dust-proof substrate 12 by contacting the outer periphery of the dust-proof substrate 12 and setting the inside of the recess 211 provided at the tip to a negative pressure from the apparatus atmosphere. It is to hold. The suction collet 210 is connected via a negative pressure path 212 and 204 to a vacuum pump 203 which is a negative pressure generating source provided in the dustproof substrate sticking apparatus 30 or in a factory. The suction collet 210 can be moved linearly in the horizontal direction and the vertical direction and rotated around the vertical axis by the operation of the transfer robot 201.

  In this embodiment, the suction collet 210 is disposed in the transport robot 210 so that the tip which is the suction surface is horizontal and faces downward. That is, the sticking surface 12a of the dustproof substrate 12 held by the suction collet 210 is horizontal and downward.

  Further, around the suction collet 210 of the transfer robot 201, a light shielding plate 213 made of a plate-like member having a light shielding property is disposed at a position separated from the suction collet 210. The light shielding plate 213 has a box shape with an opening on one surface, and is arranged so that the opening faces the same direction as the tip of the collet 210. Further, the light shielding plate 213 is disposed so that the tip of the opening is located on the same plane as the adhesion surface 12 a of the dustproof substrate 12 held by the suction collet 210.

  That is, the suction collet 210 is covered with the light shielding plate 213 in the direction in which the suction surface at the tip faces, that is, the entire circumference except for the lower side.

  As will be described in detail later, the surface inspection device 250 is a device that inspects the presence or absence of foreign matter and scratches on the adhesion surface 12a, which is the surface to be inspected, of the dust-proof substrate 12 held by the transport robot 201. is there.

  The NG stocker 290 is a device that temporarily holds the defective dust-proof substrate 12 ng recognized by the surface inspection device 250 as having foreign matters attached thereto or presenting scratches, and carries it out of the dust-proof substrate sorting device 200.

  On the other hand, the mother substrate transfer device 100 includes a transfer robot 101, a carry-in device 110, a substrate holding device 120, a substrate carry-out device 130, and an adhesive application curing device 140.

  The transport robot 101 is a horizontal articulated robot, a so-called SCARA robot, and is a device that holds and transports the mother substrate 15 carried in by the carry-in device 110.

  The carry-in device 110 is a device that carries a stocker (not shown) holding a plurality of mother substrates 15 before the dust-proof substrate 12 is attached into the mother substrate transfer device 100.

  The substrate holding device 120 is a device that temporarily holds the mother substrate 15 carried in by the transfer robot 101.

  The substrate carry-out device 130 is a device that carries out the mother substrate 15 after the dust-proof substrate 12 is attached to the outside of the mother substrate transfer device 100.

  The adhesive application curing device 140 applies a thermosetting adhesive onto the mother substrate 15 held by the substrate holding device 120, and after the dustproof substrate 12 is placed on the counter substrate 20, the thermosetting adhesive. Is a device for curing.

  The dust-proof substrate sticking process performed in the dust-proof substrate sticking apparatus 30 having the above configuration will be described below.

  First, in the mother substrate transport apparatus 100, the mother substrate 15 carried in by the carry-in device 110 is transported by the transport robot 101 and positioned and held on the substrate holding device 120. A thermosetting adhesive is applied to each counter substrate 20 of the mother substrate 15 held on the substrate holding device 120 by the adhesive application curing device 140.

  While the above-described steps are performed, in the dustproof substrate sorting apparatus 200, the dustproof substrate 12 carried in by the carry-in device 280 is transported by the transport robot 201, and the surface inspection device 250 causes the dustproof substrate 12 to be placed on the bonding surface 12a. Inspected for foreign material adhesion or scratches.

  The dust-proof substrate 12 determined by the surface inspection apparatus 250 that foreign matter is attached or scratched is transported and placed on the NG pallet 291 of the NG stocker 290 as a defective dust-proof substrate 12 ng.

  The dust-proof substrate 12 that has been judged to be non-defective by the surface inspection device 250, that is, a non-defective product, is transported by the transport robot 201 and adhered to the mother substrate 15 held by the substrate holding device 120. It is placed on the counter substrate 20 in a state where the agent is applied.

  After the dust-proof substrate 12 is placed on all the counter substrates 20, the thermosetting adhesive is cured by the adhesive application curing device 140. Thereby, the dust-proof substrate 12 is stuck on the counter substrate 20.

  The mother substrate 15 after the thermosetting adhesive is cured is transported to the substrate carry-out device 130 by the transport robot 101 and is carried out of the mother substrate transport device 100. Thus, the mother substrate 15 in a state where the dust-proof substrate 12 is stuck on the counter substrate 20 is completed, and the dust-proof substrate sticking step is completed.

  Hereinafter, the surface inspection apparatus 250 of the dustproof substrate sorting apparatus 200 which is the substrate inspection apparatus of the present embodiment will be described in detail.

  As shown in FIG. 4, the surface inspection apparatus 250 includes a control device 202, an imaging device 251, an image processing device 252, an illumination device 260, and an illumination drive device 261.

  The imaging device 251 is an electronic camera using a CCD or the like, and acquires a black and white image in this embodiment. The imaging device 251 is electrically connected to the image processing device 252 and outputs the acquired image to the image processing device 252.

  The image processing device 252 is a device that performs image processing on an image acquired by the imaging device 251. The image processing device 252 is electrically connected to the control device 202, and outputs a recognition result obtained by image processing to the control device 202.

  The illuminating device 260 is an illuminating device having a light source such as an LED, a halogen, or a xenon. In the present embodiment, a plurality of white LEDs are used as the light source. The illuminating device 260 is a so-called ring-shaped illumination in which a plurality of LEDs are arranged on the circumference and the optical axis (exit axis) of the illumination light is directed toward the center of the circumference. Needless to say, the illumination device 260 is disposed at a position where the illumination light does not directly enter the imaging device 252. The lighting device 260 is electrically connected to the lighting driving device 261.

  The illumination driving device 261 is a device that supplies power for driving the light source of the illumination device 260, and controls the lighting timing of the illumination and the intensity of the illumination light. The illumination driving device 261 is electrically connected to the control device 202.

  In the surface inspection apparatus 250 of this embodiment, the imaging device 251 and the illumination device 260 are fixed on the base of the dustproof substrate sorting apparatus 200. As shown in FIG. 4, the imaging device 251 is arranged so that the optical axis is vertically upward, and the illumination device 260 has an emission direction of illumination light from the LED as the light source of the imaging device 251. They are arranged so as to be orthogonal to the optical axis. That is, the illumination light emission direction of the illumination device 260 is the horizontal direction.

  The control device 202 includes an arithmetic device, a storage device, an input / output device, and the like, and is a device that controls the operation of each device constituting the dustproof substrate sorting device 200.

  A method for inspecting the sticking surface 12a of the dustproof substrate 12 by the surface inspection apparatus 250 having the above-described configuration will be described below.

  At the time of inspection of the sticking surface 12 a of the dustproof substrate 12, the dustproof substrate 12 is transported into the field of view of the imaging device 251 by the transport robot 101 while being held by the collet 210 as shown in FIG. 4. Here, the dust-proof substrate 12 is held such that the sticking surface 12a, which is the surface to be inspected, substantially coincides with the surface including the optical axis of the illumination light of the illumination device 260.

  In other words, the illumination device 260 is disposed on substantially the same plane as the attachment surface 12a during the inspection of the attachment surface 12a of the dust-proof substrate 12, and at this time, the illumination light emitted by the illumination device 260 is transmitted. The optical axis is substantially parallel to the sticking surface 12a.

  In a state where the dustproof substrate 12 is held at the above-described position, the illumination device 260 is turned on by the illumination drive device 261, and an image is acquired by the imaging device 251. The image acquired by the imaging device 251 is subjected to binarized image processing based on a predetermined threshold by the image processing device 252 to recognize the presence / absence of a bright spot in the image. The recognition result is input to the control device 202, and the control device 202 determines the presence / absence of foreign matter and scratches on the adhesion surface 12a of the dustproof substrate 12 from the information on the presence / absence of the bright spot. Thus, the inspection of the sticking surface 12a of the dustproof substrate 12 is completed.

The operation and effect of the substrate inspection apparatus and substrate inspection method of this embodiment will be described below.
As schematically shown in FIG. 5, when inspecting the sticking surface 12 a of the dust-proof substrate 12, the lighting device 260 is positioned substantially on the same plane as the sticking surface 12 a and is emitted from the lighting device. As shown by the arrow L1 in FIG. 4, the illumination light is irradiated at a shallow angle substantially parallel to the sticking surface 12a.

  For this reason, the illumination light is totally reflected (arrow LR1) when the surface of the sticking surface 12a is mirror-like, that is, when there is no foreign matter or scratch (region P1 in FIG. 5). For this reason, the illumination light does not enter the imaging device 251 disposed in the normal direction of the sticking surface 12a. Therefore, an area where no foreign matter or scratch exists is shown as a dark area in the image acquired by the imaging device 251. That is, the image after binarization by the image processing device 252 is recognized as black.

  On the other hand, when there is a scratch on the surface of the sticking surface 12a (region P2 in FIG. 5) or when foreign matter is attached (region P3 in FIG. 5), the illumination light is not totally reflected, and the scratch or foreign matter (LR2 and LR3 in FIG. 5) and incident on the imaging device 251. Therefore, a region where a foreign object or a flaw is present appears as a bright region, for example, a white bright spot, in an image acquired by the imaging device 251. That is, the image after binarization by the image processing device 252 is recognized as white, and is determined as defective by the control device 202 accordingly.

  Moreover, since illumination light is irradiated in the direction substantially parallel to the sticking surface 12a, it is not irradiated to the back surface 12b side of the dustproof substrate 12. Therefore, even if foreign matter or scratches exist on the back surface 12 b of the dustproof substrate 12, they do not appear in the image acquired by the imaging device 251. The same applies to the suction collet 210 and the transfer robot 201 existing on the back surface 12b side of the dustproof substrate 12, and these also do not appear in the image acquired by the imaging device 251.

  Therefore, according to the present embodiment, it becomes possible to recognize only foreign matters and scratches present on the adhesion surface 12a, which is the surface to be inspected, of the dust-proof substrate 12, which is a light-transmitting substrate, and erroneous detection It is possible to improve the detection accuracy of scratches or foreign matter.

  In the present embodiment, the side surface portion 12c and the back surface 12b of the dust-proof substrate 12 are covered with the light-shielding plate 213 when the sticking surface 12a of the dust-proof substrate 12 is inspected. For this reason, stray light (arrow L2 in FIG. 5) generated by irregular reflection or the like in the illumination device 260 and directed to the side surface portion 12c of the dustproof substrate 12 does not enter the side surface portion 12c and the back surface 12b. Similarly, ambient light from lighting in the factory does not enter the side surface portion 12c and the back surface 12b.

  Therefore, by providing the light shielding plate 213, the illumination light can be more reliably irradiated only on the bonding surface 12a, which is the surface to be inspected, and the detection accuracy of scratches or foreign matters can be further improved. It becomes.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. An inspection apparatus and an inspection method are also included in the technical scope of the present invention.

  For example, in the above-described embodiment, ring-shaped illumination is adopted as one form of the illumination device. However, in the present invention, it is not necessary to irradiate the substrate surface from all directions, for example, so-called a plurality of LEDs arranged in series. There may be a form in which only one bar-shaped illumination is provided on the same plane as the surface to be inspected of the substrate.

  In addition, the positional relationship among the surface to be inspected, the illumination device, and the imaging device is relative, for example, the optical axis of the imaging device is in the horizontal direction and the surface to be inspected of the substrate is upright. May be.

  In addition, the present embodiment is an application of the present invention to the inspection of the surface of a dustproof substrate attached to a liquid crystal display panel, but the present invention is also applicable to, for example, the inspection of the surface of a counter substrate or a mother substrate. It is possible to apply.

  Needless to say, the substrate to be inspected in the present invention is not limited to the substrate used in the liquid crystal display panel.

It is a perspective view showing the composition of a liquid crystal display panel. It is a top view explaining a mother board. It is a schematic top view explaining the structure of the board | substrate sticking apparatus for dustproof. It is a schematic block diagram explaining the structure of a board | substrate inspection apparatus. It is explanatory drawing which shows the detection method of a foreign material and a damage | wound.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 Dust-proof board | substrate, 12a Adhesion surface (surface to be inspected), 201 Conveyance robot, 202 Control device, 203 Vacuum pump, 204 Vacuum path, 210 Adsorption collet, 213 Shading plate, 251 Imaging device, 252 Image processing device, 260 Illumination Device, 261 lighting drive device

Claims (3)

A substrate inspection apparatus for inspecting one surface of a light-transmitting substrate as a surface to be inspected,
An imaging device disposed to face the surface to be inspected;
And a lighting device disposed on a plane including the surface to be inspected.   The substrate inspection apparatus according to claim 1, further comprising a light shielding unit that covers a surface of the substrate excluding the surface to be inspected. A substrate inspection method for inspecting one surface of a light-transmitting substrate as an inspection surface,
Irradiating the surface to be inspected by a light source disposed on a plane including the surface to be inspected,
A method for inspecting a substrate, wherein the surface to be inspected is imaged by an imaging device arranged to face the surface to be inspected.

Images