JP2007017996A - Substrate bonding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate bonding device which does not cause a positional deviation between upper and lower substrates in a way of conveyance of a cell and permits a desired gap even near a UV-curing agent. <P>SOLUTION: The substrate bonding device is provide with a temporary fixing mechanism S4 in which two sheets of substrates disposed within a vacuum chamber 15 are bonded to each other by pressing in an evacuated state, thereafter, adhesives 53 for temporary fixation disposed on plural parts at least on either side of both substrates are irradiated with UV light and are cured. The temporary fixing mechanism S4 is configured such that a UV fiber 45 is vacuum-shielded and arranged in a hollow cylindrical compression bar 60, which can be vertically moved in a vacuum chamber 15 while maintaining the vacuum state in the vacuum chamber 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate bonding apparatus for bonding a pair of substrates as constituent members of a liquid crystal display panel under reduced pressure, and more particularly to a substrate bonding apparatus suitable for preventing the occurrence of defective products of a liquid crystal display panel.

  For manufacturing a liquid crystal display panel, for example, an adhesive (hereinafter also referred to as “sealant”) in which two glass substrates provided with a transparent electrode, a thin film transistor array and the like are provided in a mouth shape on the peripheral edge of the substrate is used. There is a process of bonding with extremely close intervals of about 2 μm (hereinafter, the substrate after the bonding is referred to as “cell”), and sealing the liquid crystal in a space formed by each substrate and an adhesive.

Conventionally, as a method of laminating a substrate when sealing the liquid crystal, the liquid crystal is dropped on one substrate drawn in a pattern (letter shape) in which a sealing agent is closed so as not to provide an injection port. Then, the following patent in which the other substrate is placed above one substrate in a vacuum chamber, and the upper and lower substrates are bonded together by applying pressure while reducing the distance between the other substrate and one substrate in a vacuum state. There is a method disclosed in Document 1. In addition, as a method of curing the adhesive (sealing agent) when the substrates are bonded together, the sealing agent applied to the substrate is temporarily cured by irradiation energy, and then a liquid crystal is dropped onto the substrate to drop two sheets. There is a method disclosed in Patent Document 2 below in which the substrates are bonded together and then the sealing material is cured with an irradiation energy different from the irradiation energy previously irradiated.
JP 2000-284295 A Japanese Patent Laid-Open No. 10-177178

  By the way, in recent years, an increase in the size of a liquid crystal display panel has progressed, and now a substrate having a side exceeding 1000 mm and a thickness of 0.7 mm has come out. Here, when holding and lifting both ends of such a large substrate, it has been confirmed by experiments and computer analysis that it bends about 80 to 100 mm by its own weight. For this reason, the cell on which the two large substrates are bonded also bends due to its own weight in the middle of its transportation. For example, a compressive force acts on the seal surface of the lower substrate and a tensile force acts on the seal surface of the upper substrate. As a result, there is a problem in that a deviation occurs between the upper and lower substrates, causing the seal portion to break and liquid crystal to flow out.

  Further, such a large substrate is provided with a plurality of cut patterns in which a plurality of continuous seal patterns are provided on the substrate, and a liquid crystal is sealed in each pattern to create a plurality of liquid crystal display panels. May be. In such a case, the two substrates are bonded together by, for example, pressing the two substrates under reduced pressure as in the method disclosed in Patent Document 1 above. The pressure is applied to the substrate when the inside of the vacuum chamber is returned to atmospheric pressure. However, such a large substrate has a disadvantage that it is not evenly pressurized when returning to the atmospheric pressure, and the distance between the substrates does not become an appropriate gap. In order to improve such an inconvenience, that is, to apply the applied pressure uniformly, a method of adding another round of dummy seal pattern in addition to the seal pattern for sealing liquid crystal made of a sealing agent is conceivable. There is also a method in which a temporary fixing UV (ultraviolet) curing agent is applied in the vicinity of the dummy seal pattern and temporarily fixed by irradiating UV light from outside the vacuum chamber to cure the UV curing agent.

  However, in the case of these improvement methods, when the cell bonded in a vacuum is returned to atmospheric pressure, a pressure difference occurs between the inside and the outside of the dummy seal, and the height of the UV curing agent applied to the spot does not collapse. It becomes higher than the sealant. As a result, a gap defect between the substrates in the vicinity of the UV curing agent occurs, which is one of the factors that cause a color unevenness defect after lighting.

  The present invention provides a substrate bonding apparatus that improves the inconveniences of the conventional example, does not cause the positional deviation of the upper and lower substrates during the transfer of the cell, and can obtain a desired gap even near the UV curing agent. The purpose of this is to prevent the generation of defective cells.

  In order to achieve the above object, according to the present invention, after two substrates arranged in a vacuum chamber are pressed and bonded in a vacuum state, a plurality of temporary substrates are provided on at least one of the substrates. In the substrate laminating apparatus provided with a temporary fixing mechanism for irradiating and curing the fixing adhesive with UV light, the temporary fixing mechanism is arranged in a hollow cylindrical pressure bar with the UV fiber cut off in vacuum. The first feature is that the hollow cylindrical pressure bar can be moved up and down in the vacuum chamber while maintaining a reduced pressure state in the vacuum chamber.

  Furthermore, the present invention is the substrate bonding apparatus according to the above feature, wherein the hollow cylindrical pressure bar is provided with a cylindrical constriction portion that holds glass inside and abuts against the glass, and the constriction portion In the substrate bonding apparatus of the first feature, a flange is attached to the vacuum chamber, and the hollow cylindrical pressure bar is vertically moved in the flange. The second feature is that it is configured to move.

  According to the present invention, a substrate bonding apparatus is provided in a vacuum chamber at a plurality of locations on at least one of the substrates after first pressurizing two substrates at a reduced interval in the vacuum chamber in a reduced pressure state. A temporary fixing mechanism is provided for curing the temporary fixing adhesive by irradiating it with UV light while being pressurized in a vacuum chamber in a reduced pressure state. For example, the temporary fixing mechanism is a structure in which a bundle of UV fiber elements is placed in a hollow cylindrical pressure bar while being vacuum-blocked with a material that allows UV light to pass through, and the vacuum chamber is kept in a reduced pressure state. It can move up and down in the vacuum chamber.

  In the present invention, after the primary pressing step, using the temporary fixing mechanism, temporary fixing is performed by irradiating UV light while curing the temporary fixing adhesive on each substrate that has undergone the primary pressing step. Perform the process. For example, in this temporary fixing step, the portion of the substrate where the adhesive for temporary fixing is provided at the tip of the hollow cylindrical pressure bar is pressed with a predetermined force, and the gap between the substrates in the pressurized portion is made the final gap. The temporary fixing adhesive sandwiched between the substrates is cured by UV irradiation. As a result, only the portion where the temporary fixing adhesive is provided becomes the final gap, and temporary fixing at this position is possible. In the present invention, after the temporary fixing step, a secondary pressurizing step is performed in which the inside of the vacuum chamber is returned to the atmospheric pressure to perform pressurization and bonding.

  According to the substrate bonding apparatus according to the present invention, the distance between the substrates in the portion where the temporary fixing adhesive is provided can be set to a desired gap under reduced pressure, and can be temporarily fixed at such a position, so that it is finally desired. The distance between the substrates can be maintained. In addition, even in a cell in which two large substrates are bonded as in the conventional example, the cell is finally fixed while maintaining a desired inter-substrate distance. Can be prevented. As a result, the generation of defective cells can be prevented.

[First embodiment]
1st Embodiment of the board | substrate bonding apparatus which concerns on this invention is described based on FIG. 5 from FIG.
[Configuration of substrate bonding equipment]
If this board | substrate bonding apparatus is divided roughly as shown in FIG. 1, two board | substrates 33 and 34 (henceforth the board | substrate 33 mounted and hold | maintained on the table 9 mentioned later is called "lower board | substrate 33" if it categorizes roughly. , A substrate 34 held on the pressure plate 16 to be described later is referred to as an “upper substrate 34”), an XYθ stage portion S1 for positioning, a substrate bonding portion S2 for performing bonding operations of the substrates 33 and 34, and a later-described. Each substrate 33, 34 is composed of a Z-axis moving stage portion S 3 that performs primary pressurization, and the respective portions S 1, S 2, S 3 are sequentially arranged on the gantry 1. Here, the XYθ stage unit S1 is placed and held on the gantry 1, and the substrate bonding unit S2 is supported by a first frame 2 provided with, for example, four support columns standing on the gantry 1, and a Z-axis moving stage. The part S3 is supported by the second frame 3 provided with, for example, four support columns provided on the gantry 1. Hereinafter, these parts S1, S2, and S3 will be described in detail.
[XYθ stage section]

  The XYθ stage unit S1 includes an X stage 4a disposed on the gantry 1, a Y stage 4b disposed on the X stage 4a, and a θ stage 4c disposed on the Y stage 4b. . The X stage 4a of the present embodiment is configured such that the drive motor 5 can move the Y stage 4b and the θ stage 4c in the left-right direction (X-axis direction in FIG. 1). The Y stage 4b is configured to be able to move the θ stage 4c in the front-rear direction (Y-axis direction in FIG. 1) by the drive motor 6. Furthermore, the θ stage 4 c is configured to rotate in the θ direction shown in FIG. 1 with respect to the Y stage 4 b by the drive motor 8 through the rotary bearing 7.

  Here, on the θ stage 4 c, a table 9 for mounting and holding the lower substrate 33 is fixed via a support column 10. Further, the Y stage 4 b is provided with an arm 11 that encloses the lower side of the support column 10 via a rotary bearing 13 and a vacuum seal 14, so that the arm 11 is moved along with the rotation of the support column 10. It is designed not to rotate. Furthermore, between the arm 11 and a vacuum bonding chamber 15 (to be described later) of the substrate bonding portion S2, one end is fixed on the arm 11 and the other end is fixed to the lower portion of the vacuum bonding chamber 15 and supported. A vacuum bellows 12 made of an accordion-like elastic body covering the column 10 is disposed, thereby maintaining a reduced pressure state in the vacuum bonding chamber 15 at the time of bonding.

In the present embodiment, one support column 10 is disposed at substantially the center of the table 9, but the present invention is not limited to this. For example, a predetermined amount of the table 9 by the θ stage 4c (described later). A plurality of support columns 10 may be provided as long as the rotation enough to correct the misalignment amount of the alignment mark is possible.
[Board bonding part]

  As shown in FIG. 1, the substrate bonding portion S2 is arranged in a vacuum bonding chamber (vacuum chamber) 15 for bonding two substrates 33 and 34 under reduced pressure, and in the vacuum bonding chamber 15. The table 9 is provided, and the pressure plate 16 is disposed in the vacuum bonding chamber 15 so as to be opposed to the upper side of the table 9. In this case, a lower substrate 33 provided with a dummy seal 54, a UV curing agent 53, an adhesive 37, and a liquid crystal 39, which will be described later, is placed and held on the table 9, and the pressure plate 16 is bonded to the lower substrate 33. The substrate 34 is held.

  A side opening of the vacuum bonding chamber 15 is provided with a first opening 15a for entering and exiting the substrates 33 and 34, and a gate valve 17 for closing the first opening 15a is provided. Yes. Here, the gate valve 17 is configured to be movable in the vertical direction (Z-axis direction in FIG. 1) by the cylinder 17A.

  Furthermore, the 1st and 2nd exhaust pipe 20a, 20b for evacuating the inside of the vacuum bonding chamber 15 is arrange | positioned in the lower part of the vacuum bonding chamber 15, These exhaust pipes 20a, 20b are respectively It is connected to a vacuum pump via a switching valve (not shown). Here, the first exhaust pipe 20a is thinner than the second exhaust pipe 20b. For example, in the case of an exhaust pipe having a substantially circular cross section, if the diameter of the first exhaust pipe 20a is 1, the larger one is used. The second exhaust pipe 20b has a diameter of about 10 to 100 times. In this case, the diameter of the first exhaust pipe 20a is such that when the inside of the vacuum bonding chamber 15 is evacuated from the first exhaust pipe 20a as will be described later, the substrates 33 and 34 are disturbed by the gas flow, and the lower substrate 33 The speed is set so that the liquid crystal does not scatter and water freezes due to reduced pressure. For example, when the diameter is set, the first exhaust pipe 20a having a diameter determined based on the experimental result is arranged in advance with piping having various diameters. Here, the pressure in the vacuum bonding chamber 15 at the time of bonding in the present embodiment is about 0.67 Pa (5 × 10 −3 Torr).

  In the present embodiment, the first and second exhaust pipes 20a and 20b having different thicknesses are switched by the switching valve to change the exhaust path, thereby controlling the exhaust speed. For example, as in the present embodiment, the two exhaust pipes 20a and 20b are not provided, but only one exhaust pipe is provided, a vacuum pump is connected to the exhaust pipe, and the vacuum pump is controlled. The exhaust speed may be controlled. In this case, it is desirable that the exhaust pipe has a larger diameter (that is, the diameter of the second exhaust pipe 20b of the present embodiment).

  Further, on the table 9 side in the vacuum bonding chamber 15, a plurality of lifting pins 35 used for receiving the lower substrate 33 from a transfer machine (not shown) or taking out a cell are provided upright. A cylinder 36 is disposed at one end (the lower end in FIG. 1) of the elevating pin 35, and the cylinder 36 is configured to be able to move in a vertical direction in a through hole formed in the table 9.

  Furthermore, a pipe 21 for returning the decompressed state in the vacuum bonding chamber 15 to atmospheric pressure is introduced into the upper portion of the vacuum bonding chamber 15 and gas (air) is introduced into or shut off from the vacuum bonding chamber 15. For this purpose, a valve 22 provided in the middle of the pipe 21 is provided. Here, a pressure source (for example, a pump) (not shown) is connected to the pipe 21, so that the gas introduction speed into the vacuum bonding chamber 15 can be controlled. Note that the pressure source is not necessarily provided.

  Further, a plate-like shape that closes the substantially circular second opening 15b formed in the vacuum bonding chamber 15 on the side surface of the vacuum bonding chamber 15 (the side opposite to the side on which the gate valve 17 is provided). An air release valve 23 made of a body and a cylinder 24 for separating the air release valve 23 from the second opening 15b are disposed. Thus, by providing the air release valve 23 and separating the air release valve 23 from the second opening 15b, the inside of the vacuum bonding chamber 15 can be rapidly returned to atmospheric pressure. Here, when the pipe 21 having a substantially circular cross section is used, if the diameter of the pipe 21 is 1, the diameter of the second opening 15b is desirably 5 or more.

  Further, a plurality of windows 25 for observing the alignment marks of the upper and lower substrates 33 and 34 through a mark recognition hole (not shown) formed in the pressure plate 16 are provided in the upper part of the vacuum bonding chamber 15. Here, the recognition camera 26 shown in FIG. 1 is used for observing the alignment mark, and the displacement of the alignment mark on each of the substrates 33 and 34 is measured by the recognition camera 26.

  Subsequently, the table 9 is provided with an electrostatic suction electrode (not shown) and a plurality of suction suction holes 9a for sucking the lower substrate 33 by static electricity or suction suction.

  In this embodiment, the electrostatic chucking electrode is a substantially rectangular flat plate electrode, and is fitted into two substantially rectangular recesses formed on both ends of the upper surface of the table 9. Further, the surface of the electrostatic attraction electrode (the upper surface side of the table 9) is covered with a dielectric, and the main surface of the dielectric is provided so as to be flush with the upper surface of the table 9. Thus, the electrostatic chucking electrodes arranged on the table 9 are respectively connected to positive and negative DC power sources via appropriate switches. Therefore, when a positive or negative voltage is applied to each electrostatic chucking electrode, a negative or positive charge is induced on the main surface of the dielectric. Then, the lower substrate 33 is electrostatically attracted to the table 9 by a Coulomb force generated between the transparent electrode film formed on the lower substrate 33 by the electric charge. Here, the voltage applied to each electrode for electrostatic attraction may be the same polarity, or may be different from each other.

  In addition, when the inside of the vacuum bonding chamber 15 is air | atmosphere, it is better to perform attraction | suction adsorption by the attraction | suction adsorption hole 9a mentioned above. The reason is that, when electrostatic adsorption is performed, if there is an air layer between the lower substrate 33 and the table 9, a discharge phenomenon due to static electricity occurs and the lower substrate 33 and the table 9 are damaged. For this reason, for example, when the lower substrate 33 is first tightly held on the table 9, the surroundings are in the atmosphere, so suction suction is performed first, and the pressure is reduced to such an extent that no discharge phenomenon occurs by reducing the pressure in the vacuum chamber. It is desirable to perform electrostatic adsorption.

  Next, each suction suction hole 9a is connected to a suction valve (not shown) disposed outside the vacuum bonding chamber 15 via a pipe 18, and is connected to a vacuum pump (not shown) via this suction valve. . In this case, a bypass pipe is provided in the middle of the pipe 18 for opening to the atmosphere via a suction / adsorption release valve, and the suction state is forcibly released by opening the suction / adsorption release valve to the atmosphere. It has been released. The table 9 configured in this manner is fixed on the θ stage 4c via the support column 10 as described above.

  The pressure plate 16 is provided with an electrostatic chucking electrode and a plurality of suction chucking holes 16 a for sucking the upper substrate 34, similar to the table 9. Here, as will be described later, if the pressure inside the vacuum bonding chamber 15 is reduced while the upper substrate 34 is sucked and sucked by the pressure plate 16, the suction force may be reduced and the upper substrate 34 may fall. is there. Therefore, a substrate holding claw (not shown) that receives the upper substrate 34 at a position slightly below the pressure plate 16 is provided in the vacuum bonding chamber 15. The substrate holding claws are disposed corresponding to, for example, two corners that are diagonal positions of the upper substrate 34, and are suspended and held by a shaft extending downward from the upper portion of the vacuum bonding chamber 15. The

  Specifically, although not shown, a shaft is inserted through a through hole formed in the upper portion of the vacuum bonding chamber 15, and this shaft is configured to rotate about its axis and move up and down. In this case, the shaft is covered with a vacuum seal so as not to cause a vacuum leak in the vacuum bonding chamber 15. The rotation is performed by a rotation actuator (not shown) connected to the end of the shaft, and the vertical movement is similarly performed by a lift actuator (not shown) connected to the end of the shaft. By rotating or vertically moving the shaft in this manner, the substrates 33 and 34 are bonded to each other, and the liquid crystal agent dropped on the lower substrate 33 is expanded in the spreading direction of the main surfaces of the substrates 33 and 34. The substrate holding claw can be retracted so as not to get in the way.

  Each of the suction suction holes 16a is connected to a suction valve (not shown) disposed outside the vacuum bonding chamber 15 via a pipe 19, and is connected to a vacuum pump (not shown) via the suction valve. In this case, a bypass pipe is provided in the middle of the pipe 19 for opening to the atmosphere via a suction suction release valve in the same manner as the table 9, and the suction is released by opening the suction suction release valve to the atmosphere. The state is forcibly released. The pressure plate 16 configured in this manner is suspended and fixed to a later-described moving base 29 of the Z-axis moving stage unit S3 via a plurality of support columns 27.

  Here, between the vacuum bonding chamber 15 and the moving base 29, one end is fixed on the vacuum bonding chamber 15 and the other end is fixed to the lower portion of the moving base 29, and the bellows is provided on the support column 27. A vacuum bellows 28 made of an elastic body is disposed, and this maintains a decompressed state in the vacuum bonding chamber 15 at the time of bonding.

  Further, as shown in FIG. 1, a pressure plate 16 is placed on the upper portion of the vacuum bonding chamber 15 after the primary pressurization described later (after the substrates 33 and 34 are pressed and bonded in a reduced pressure state). In the raised state, there is provided a temporary fixing mechanism portion S4 for irradiating and curing the UV light while pressurizing the UV fixing agent 53 for temporary fixing provided in advance on the lower substrate 33. Below, this temporary fixing mechanism part S4 is demonstrated using FIG.

  The temporary fixing mechanism portion S4 includes a glass holder 42 made of a cylindrical body that holds the glass 44 inside, and a screwed portion of the glass holder 42 from its tip portion (portion disposed in the vacuum bonding chamber 15). A hollow cylindrical pressure bar 60 comprising a cylindrical body to be worn, a UV fiber 45 for UV light irradiation disposed inside the hollow cylindrical pressure bar 60 and in the vicinity of the glass 44, and a vacuum bonding chamber 15. It has a flange 50 that is fixed to the upper surface via a vacuum interrupting O-ring 46 and that has a cylindrical body through which the hollow cylindrical pressure bar 60 is inserted, and a moving means that moves the hollow cylindrical pressure bar 60 in the vertical direction.

  The moving means of the present embodiment includes a cylinder 49 that urges the vertical movement of the hollow cylindrical pressure bar 60, a cylinder fixing bracket 52 for fixing the cylinder 49 disposed on the outer peripheral portion of the flange 50, and a hollow cylindrical pressure bar. The connecting member 48 is disposed at one end (the upper end in FIG. 2) of the bar 60 and is fixed to the operating portion (moving shaft) of the cylinder 49. A bearing 51 is provided in the flange 50 so that the hollow cylindrical pressure bar 60 can move up and down smoothly. Here, when the hollow cylindrical pressure bar 60 moves up and down, the UV fiber 45 also moves up and down together. Therefore, in order to prevent damage to the UV fiber 45 extending from one end of the hollow cylindrical pressure bar 60, The extended portion is fixed to the connecting metal 48 by the fixing metal 55. By fixing in this way, stress on the UV fiber 45 during vertical movement can be reduced, and for example, the tearing can be prevented.

  Here, at the tip of the glass holder 42, a cylindrical narrowed portion that abuts the lower surface of the glass 44 is provided. As a result, as will be described later, even if the constricted portion presses the substrate, the pressing surface is small, so that no pressure is simultaneously applied to the adjacent UV curing agent 53. Further, since the narrowed portion serves as a UV light irradiation port, the substrate is not directly irradiated with UV light through the glass 44.

  Further, a vacuum blocking O-ring 41 is provided at the joining end of the glass holder 42 and the hollow cylindrical pressure bar 60, and a vacuum blocking O-ring 43 is provided between the glass holder 42 and the glass 44 in the vacuum bonding chamber 15. A vacuum interrupting O-ring 46 is disposed between the upper surface and the lower surface of the flange 50, and a vacuum interrupting O-ring 47 is disposed between the inner periphery of the flange 50 and the outer periphery of the hollow cylindrical pressure bar 60. Thus, the reduced pressure state in the vacuum bonding chamber 15 can be maintained. That is, since the inside of the hollow cylindrical pressure bar 60 becomes atmospheric pressure, the UV fiber 45 is disposed at a position closest to the substrate (for example, in the vicinity of the glass 44) using this portion. Since the UV fiber 45 is disposed at such a position, the attenuation of the UV light applied to the substrate is small, and there is no need to provide a condensing lens having a large aperture. For this reason, the glass 44 having the best UV light transmittance, for example, quartz glass is suitable.

A plurality of temporary fixing mechanism portions S4 configured as described above may be provided by design and within a possible range by examining the effective bonding position. However, at least two temporary fixing mechanism portions S4 may be provided on each side of the substrate as shown in FIG. It is desirable to provide each location (above the UV curing agent 53 in FIG. 3). Further, if the reduced pressure state in the vacuum bonding chamber 15 can be maintained, a movement mechanism for moving the temporary fixing mechanism portion S4 in the horizontal direction on the substrate is added to the temporary fixing mechanism portion S4. You may comprise so that it may provide one place in a edge | side.
[Z-axis moving stage]

The Z-axis moving stage unit S3 includes a moving base 29 for suspending and holding the pressure plate 16, linear guides 30 disposed at both ends thereof, and a vertical direction that is engaged with the linear guide 30 and provided on the frame 3. The rail 3a (in the Z-axis direction shown in FIG. 1), the electric motor 32 having an output shaft in the Z-axis direction, one end engaged with the moving base 29 side, and the other end on the output shaft side of the electric motor 32 And a ball screw 31 to be engaged. By configuring the Z-axis moving stage unit S3 in this way, the moving base 29 can be moved in the vertical direction along the rail by the driven electric motor 32, and the pressure plate 16 can be moved up and down.
[Operation of substrate bonding equipment]

  Next, the operation of the substrate bonding apparatus according to this embodiment will be described. Here, a case where a substrate for a liquid crystal panel is used as the substrate to be bonded is illustrated.

  As shown in FIG. 3, a sealing agent for sealing a liquid crystal is used in order to confine and enclose the liquid crystal in a predetermined frame when the respective substrates are bonded together. (Adhesive) 37 is used to provide a seamless frame. Further, a frame (hereinafter referred to as “dummy seal”) 54 is also provided separately from the adhesive 37 so as to surround the frame. Further, a UV curing agent 53 is provided in the form of a dot or a line having a certain length near the substrate end portion side of the dummy seal 54. Then, a predetermined amount of liquid crystal 39 is dropped into a liquid crystal sealing frame made of an adhesive 37. In the present embodiment, the substrate on which the liquid crystal 39 or the like is dropped is referred to as the lower substrate 33. Here, the dummy seal 54 may not be provided. Even in such a case, the UV curing agent 53 is provided at substantially the same position.

  First, using the hand of a transfer machine (not shown) disposed outside the vacuum bonding chamber 15, the peripheral edge of the upper substrate 34 with the film surface facing downward is sucked and adsorbed from below. Then, the gate valve 17 provided in the first opening 15a of the vacuum bonding chamber 15 is opened, the hand of the transfer machine is inserted into the vacuum bonding chamber 15 from the first opening 15a, and the electric motor 32 is driven. Then, the pressure plate 16 lowered is pressed against the upper substrate 34. Thereafter, the suction suction of the hand is released, the vacuum pump is operated, and the upper substrate 34 is sucked and sucked to the pressure plate 16 through the suction suction holes 16a. When the suction of the upper substrate 34 is completed, the hand is retracted out of the vacuum bonding chamber 15.

  Subsequently, each lift pin 35 is raised by operating the cylinder 36 so that the tip of the lift pin 35 protrudes from the upper surface of the table 9. Then, the peripheral portion of the lower substrate 33 with the liquid crystal dripped surface is sucked and adsorbed from below by the hand of the transfer machine, and the hand is inserted into the vacuum bonding chamber 15 to move the lower substrate 33 up and down. Transfer on the pin 35. When the transfer of the lower substrate 33 is completed, the hand is retracted out of the vacuum bonding chamber 15 and the gate valve 17 is closed. Thereafter, the respective raising and lowering pins 35 are lowered to place the lower substrate 33 on the table 9, and the vacuum pump is operated to suck and suck the lower substrate 33 to the table 9 through the suction suction holes 9a.

  When the adsorption of the substrates 33 and 34 to the table 9 and the pressure plate 16 is completed as described above, the valve in the first exhaust pipe 20a side is opened, and the gas in the vacuum bonding chamber 15 is gradually exhausted. Specifically, in the present embodiment, the first and second exhaust pipes 20a and 20b are both closed by the switching valve in the initial state of the apparatus, and the respective substrates 33 and 34 are set. When the adsorption is completed, the switching valve is switched so that the first exhaust pipe 20a side is opened and the second exhaust pipe 20b side is closed, and the gas in the vacuum bonding chamber 15 is gradually exhausted. In this case, since the first exhaust pipe 20a having the diameter set as described above is exhausted at a low speed, the substrates 33 and 34 are disturbed by the gas flow, the liquid crystal is scattered on the lower substrate 33, and moisture is depressurized. Freezing can be prevented from occurring.

  Subsequently, when the inside of the vacuum bonding chamber 15 reaches a predetermined pressure by exhausting through the first exhaust pipe 20a, specifically, the air pressure in the vacuum bonding chamber 15 measured by a pressure gauge (not shown) is the exhaust speed. When the pressure is such that the substrate does not violate, the liquid crystal scatters, or the water freezes even when the pressure is raised (for example, when the upper substrate 34 adsorbed by the suction adsorption force is reduced to a pressure that does not separate from the pressure plate 16) Then, the valve of the first exhaust pipe 20a is closed.

  And the valve | bulb of the 2nd exhaust pipe 20b is open | released, and the inside of the vacuum bonding chamber 15 is rapidly pressure-reduced to the pressure (about 0.67 Pa in this embodiment) for bonding each board | substrate 33 and 34 together. Here, since the atmospheric pressure in the vacuum bonding chamber 15 is lower than the suction and adsorption force of the upper substrate 34 under the pressure, the upper substrate 34 is separated from the pressure plate 16. However, the above-described substrate holding claw is provided on the lower surface side of the pressure plate 16, and the upper substrate 34 is held by moving the substrate holding claw by the above-described rotary actuator or lifting actuator. It is not separated from the pressure plate 16.

  As described above, when the decompression in the vacuum bonding chamber 15 is finished, the electrostatic chucking electrodes of the table 9 and the pressure plate 16 are arranged so that the substrates 33 and 34 can be attracted to the table 9 and the pressure plate 16 even in a vacuum. A voltage is applied to electrostatically attract the substrates 33 and 34. Thereafter, the electric motor 32 is driven to lower the moving base 29, so that the upper substrate 34 approaches the lower substrate 33. Then, the alignment mark provided on each of the substrates 33 and 34 is observed using the recognition camera 26 to measure the positional deviation between the substrates 33 and 34, and the X stage 4a, the Y stage 4b, and θ are measured based on the measured values. By controlling the operation of the stage 4c, the table 9 is moved horizontally, and the lower substrate 33 and the upper substrate 34 are aligned with high accuracy.

  When the alignment is completed, the moving base 29 is further lowered to crush the UV curing agent 53, the dummy seal 54 and the adhesive 37 with the upper substrate 34, and the liquid crystal is sealed in the frame formed by the adhesive 37. To the state. In this way, primary pressurization is completed. After this primary pressurization, the voltage applied to the electrostatic adsorption electrode of the pressure plate 16 is cut, and the electric motor 32 is driven to raise the pressure plate 16.

  Here, the state of each of the substrates 33 and 34 after the primary pressurization is shown in FIG. In this case, the distance between the substrates 33 and 34 is about 15 μm, which is not yet a desired distance. For this reason, the amount of crushing of the adhesive 37 is small, and the contact area of the adhesive 37 with each of the substrates 33 and 34 is small (the length of the contact portion is short), so the bonding state is incomplete. Further, the liquid crystal 39 in the frame of the adhesive 37 does not spread, and a large vacuum space 40 is formed between the liquid crystals 39.

  Here, when the pressure in the vacuum bonding chamber 15 is changed from the reduced pressure state to the atmospheric pressure, the space portion between the substrates 33 and 34 (the vacuum space portion 40 described above) is in the reduced pressure state. A large pressure is applied to 34 from the outside substantially uniformly. For example, when the size of each of the substrates 33 and 34 is 1200 mm × 1000 mm, a force of 121.6 kN can be applied by applying atmospheric pressure when the space between the substrates 33 and 34 is in a reduced pressure state. For this reason, in the present embodiment, as will be described later, secondary pressurization is performed so that an appropriate substrate interval is 5 μm or less, preferably 4 μm or less.

  As described above, when the pressure in the vacuum bonding chamber 15 is changed from the reduced pressure state to the atmospheric pressure after the completion of the primary pressurization, the pressure can be applied to each of the substrates 33 and 34 substantially uniformly. However, when the pressure is suddenly returned to the atmospheric pressure, the adhesive 37 is not yet sufficiently crushed as described above, so the gas introduced into the vacuum bonding chamber 15 breaks the dummy seal 54 and the adhesive 37. It enters the vacuum space 40 and becomes a defective product as a liquid crystal substrate. Alternatively, in the middle of unloading after returning to atmospheric pressure, a compressive force is applied to the sealing surface of one substrate and a tensile force is applied to the sealing surface of the other substrate as in the conventional example described above, whereby the upper and lower substrates 33, Therefore, the seal portion (adhesive 37, dummy seal 54) breaks down and the liquid crystal 39 is washed away, resulting in a defective liquid crystal substrate.

  Therefore, in the present embodiment, after the primary pressurization is finished and before the secondary pressurization is started, the UV curing agent 53 provided separately from the adhesive 37 and the dummy seal 54 is provided with the final gap (appropriate, That is, the pressure is locally applied to a desired substrate interval), and then the UV curing agent 53 is irradiated with UV light to temporarily fix it. Below, this temporary fix | stop is explained in full detail using FIG.

  First, the cylinder 49 shown in FIG. 2 is driven to lower the hollow cylindrical pressure bar 60 from above the position of the UV curing agent 53 in each substrate 33, 34, and each substrate 33, 34 at the tip of the narrow portion of the glass holder 42. Is pressed with a predetermined force to make the substrate gap the final gap. In this state, UV light is irradiated from the UV fiber 45. Since the UV light passes through the vacuum-blocked glass 44 and is irradiated onto the UV curing agent 53, the UV curing agent 53 is cured and temporarily fixed. The pressure applied when pressing the glass holder 42 against the substrate is preferably about 0.1 MPa to 0.5 MPa although it depends on the UV curing agent 53.

  After the temporary fixing is performed as described above, the cylinder 24 is operated, and the atmosphere release valve 23 for rapidly returning the inside of the vacuum bonding chamber 15 to the atmospheric pressure is opened to apply pressure to the substrates 33 and 34. (Secondary pressurization). As a result, a pressure is applied to the substrates 33 and 34 as described above, and the substrates 33 and 34 are finally pressure-bonded.

  As described above, after the primary pressure is applied under a reduced pressure condition, the temporary fixing UV curing agent 53 provided at a place other than the seal portion (adhesive 37, dummy seal 54) is pressurized to a desired substrate interval and cured. Then, since the inside of the vacuum bonding chamber 15 is returned to atmospheric pressure and the substrates are subjected to main pressure bonding, even if the inside of the vacuum bonding chamber 15 is suddenly returned to atmospheric pressure, It is possible to prevent occurrence of leakage of the liquid crystal 39 and displacement of the substrates due to breakage.

  As described above, when the bonding is completed and the pressure in the vacuum bonding chamber 15 reaches atmospheric pressure, the gate valve 17 is opened. Then, the hollow cylindrical pressure bar 60 is raised, the voltage applied to the electrostatic suction electrode of the table 9 is cut off, and the suction in the suction suction hole 9a is released. Push up from above. Thereafter, the hand of the transfer machine is inserted into the lower part of the cell (between the cell and the table 9) through the first opening 15a, and the cell is transferred onto the hand and carried out of the vacuum bonding chamber 15.

  In addition, after the temporary fixing, the inside of the vacuum bonding chamber 15 may not be rapidly returned to the atmospheric pressure, but may be performed as follows. First, after temporarily fixing, the valve 22 of the thin pipe 21 is opened, and a gas pressurized from a pressure source connected to the pipe 21 is introduced into the vacuum bonding chamber 15 to gradually return to the atmospheric pressure. When the inside of the vacuum bonding chamber 15 is gradually returned to atmospheric pressure in this way, pressure is gradually applied to the substrates 33 and 34, and the seal portions (adhesive 37 and dummy seal 54) are gradually crushed. . As a result, the contact area between the seal portion and each of the substrates 33 and 34 also gradually increases. Thus, since the difference between the internal pressure of the vacuum space 40 and the pressure in the vacuum bonding chamber 15 is gradually increased, it is possible to more effectively prevent the introduced gas from entering the vacuum space 40. it can.

  For example, the distance between the substrates 33 and 34 in this state is about 10 μm. Here, as described above, when the gas is introduced into the vacuum bonding chamber 15, the adhesive 37 is crushed to flow, and the viscosity is reduced by thixotropy. And in the state which the viscosity fell, the air release valve 23 for returning the inside of the vacuum bonding chamber 15 to atmospheric pressure rapidly is open | released, and a pressurizing force is further applied to each board | substrate 33,34. Specifically, by detecting that the pressure gauge provided in the vacuum bonding chamber 15 exceeds a predetermined pressure, the valve 22 is closed, and the cylinder 24 is operated to open the atmosphere release valve 23, A pressure is applied to each of the substrates 33 and 34 to complete the bonding. For example, as the predetermined pressure, if the introduced gas breaks the adhesive 37 and does not enter the vacuum space 40, the pressure is detected in advance by experiments and the pressure is set. Good.

  By rapidly returning the inside of the vacuum bonding chamber 15 to the atmospheric pressure through the steps as described above, the contact area of the adhesive 37 spreads with respect to the substrates 33 and 34, and the sealing performance is improved. Intrusion of gas into the water can be prevented more effectively. In addition, since the viscosity of the adhesive 37 is reduced, the adhesive 37 is quickly crushed, and the liquid crystal 39 is also crushed and spread, so that the bonding time of the substrates 33 and 34 is shortened.

Further, after the primary pressurization, the gas may be introduced by the pipe 21 and the valve 22, and the temporary fixing described above may be performed after the predetermined pressure is reached. In such a case, after the temporary fixing, the main pressure bonding is performed by suddenly setting the inside of the vacuum bonding chamber 15 to atmospheric pressure.
[Second Embodiment]

Next, a second embodiment of the substrate bonding apparatus according to the present invention will be described with reference to FIG.
This substrate bonding apparatus is different from the apparatus of the first embodiment described above in the following points, and the other configuration is the same as that of the first embodiment. Specifically, a temporary fixing mechanism portion S4 having the same configuration as that of the first embodiment is disposed at the lower portion of the vacuum bonding chamber 15. And this temporary fixing mechanism part S4 is set as the structure which gave the function similar to the raising / lowering pin 35 of 1st embodiment. Accordingly, in this embodiment, it is possible to lift the substrate while temporarily fixing with UV light as in the first embodiment without providing the lifting pins 35, which can contribute to shortening the working time.

  As described above, the temporary fixing mechanism portion S4 is configured as in the present embodiment, thereby preventing liquid crystal leakage and substrate displacement caused by breakage of the seal portion when the inside of the vacuum bonding chamber 15 is suddenly returned to atmospheric pressure. In addition to the same effects as the first embodiment, it is possible to prevent a significant increase in the number of parts constituting the apparatus.

It is the schematic block diagram which looked at 1st embodiment of the board | substrate bonding apparatus of this invention from the side surface. It is sectional drawing which shows the structure of the temporary fixing mechanism part of this embodiment. It is a top view explaining the application | coating position of the UV hardening agent on the board | substrate in this embodiment, ie, the arrangement position of the temporary fixing mechanism part with respect to a board | substrate. It is a side view which shows an example of the state of a pair of board | substrate after the primary pressurization in this embodiment. It is a side view which shows an example of the state of a pair of board | substrate at the time of temporary fixing in this embodiment. It is the figure which looked at 2nd embodiment of the board | substrate bonding apparatus of this invention from the side surface, Comprising: It is explanatory drawing explaining the arrangement | positioning position of the temporary fixing mechanism part of this embodiment.

Explanation of symbols

9: Table, 15: Vacuum bonding chamber (vacuum chamber), 16: Pressure plate, 20a: First exhaust pipe 20b: Second exhaust pipe, 21: Piping, 22: Valve, 23: Atmospheric release valve, 33, 34 : Substrate, 37: adhesive, 39: liquid crystal, 40: vacuum space, 53: UV curing agent (adhesive for temporary fixing), 54: dummy seal, S4: temporary fixing mechanism.

Claims (3)

After the two substrates placed in the vacuum chamber are pressure bonded together in a vacuum state, UV light is irradiated to the temporary fixing adhesive provided at a plurality of positions on at least one of the substrates. In a substrate laminating apparatus equipped with a temporary fixing mechanism to be cured by
The temporary fixing mechanism is arranged by vacuum blocking the UV fiber in a hollow cylindrical pressure bar, and the hollow cylindrical pressure bar is moved up and down in the vacuum chamber while maintaining a reduced pressure state in the vacuum chamber. A substrate bonding apparatus characterized by being configured to be movable. In the board | substrate bonding apparatus of Claim 1,
A substrate laminating apparatus in which glass is held inside the hollow cylindrical pressure bar, and a cylindrical constriction is provided in contact with the glass, and pressure is applied to the substrate at the constriction. . In the board | substrate bonding apparatus of Claim 1,
A substrate bonding apparatus, wherein a flange is attached to the vacuum chamber, and the hollow cylindrical pressure bar moves up and down in the flange.

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