JP5000173B2 - Substrate bonding apparatus and substrate bonding method - Google Patents

Description

  In the present invention, the upper stage and the lower stage provided in the chamber are relatively moved in the vertical direction, and the upper substrate held on the upper stage and the lower substrate held on the lower stage are decompressed in the chamber. The present invention relates to a substrate bonding apparatus and a substrate bonding method.

In the manufacturing process of the liquid crystal display panel, a paste-like sealant is applied in a frame shape to the lower substrate among the upper substrate and the lower substrate made of rectangular transparent glass or resin, and within the region surrounded by the sealant A liquid crystal is dropped on the substrate, and the lower substrate and the upper substrate are bonded together under a reduced pressure atmosphere.

  As an apparatus for performing such substrate bonding, a substrate bonding apparatus described in Patent Document 1 is known.

  The operation of such a substrate bonding apparatus will be described with reference to FIG.

  (1) Of the upper and lower substrates 1 and 2, first, the upper substrate 1 is sucked and held on the arm 23 of the transfer robot, and is transferred from the loading / unloading port 21 of the chamber 11 to a position facing the lower surface of the upper stage 12.

  (2) The upper stage 12 is lowered, the upper substrate 1 is sucked and held by an upper substrate suction means (not shown) on the lower surface of the upper stage 12, and then the upper stage 12 is raised to its original height (FIG. 6). State shown in). Thereafter, the arm 23 of the transfer robot is retracted.

  (3) The lower substrate 2 is sucked and held on the arm 23 of the transfer robot, and is loaded from the loading / unloading port 21 of the chamber 11 to a position facing the upper surface of the upper stage 12. Place on the lift pins shown. Thereafter, the arm 23 is retracted. Next, the lift pin is lowered, and the lower substrate 2 is sucked and held on the upper surface of the lower stage 13 by a lower substrate sucking means (not shown).

  (4) The loading / unloading port 21 of the chamber 11 is closed by the shutter 22, and the inside of the chamber 11 is depressurized to a vacuum state necessary for bonding.

  (5) From the state when the upper substrate 1 and the lower substrate 2 are supplied onto the upper stage 12 and the lower stage 13, respectively, the upper substrate 1 is lowered and the upper substrate 1 is brought close to the lower substrate 2, and in this state The substrates 1 and 2 are positioned in the surface direction, and then the upper substrate 1 is further lowered to press the upper and lower substrates 1 and 2 and the upper and lower substrates 1 and 2 are bonded together with a sealant.

  (6) The inside of the vacuum chamber 11 is increased to atmospheric pressure by supplying nitrogen gas or dry air.

  Here, conventionally, when the two substrates 1 and 2 are held by the upper and lower stages 12 and 13 and the pressure in the chamber 11 is reduced, the interval between the opposing surfaces of the upper and lower stages 12 and 13 is shown in FIG. As described above, the distance D1 is set when the upper and lower substrates 1 and 2 are supplied from the loading / unloading port 21 of the chamber 11 to the upper and lower stages 12 and 13. The distance D1 between the opposing surfaces of the upper and lower stages 12 and 13 at this time was set to 100 mm or more in order to avoid interference with the arm 23.

  In recent years, with the increase in size of the substrate, there is a concern that the temperature change of the upper and lower substrates 1 and 2 that occurs during decompression affects the bonding accuracy of the substrates. That is, when the substrates 1 and 2 are respectively held on the upper and lower stages 12 and 13 and the inside of the chamber 11 is decompressed to a vacuum state, the temperature of the atmosphere in the chamber 11 is lowered due to the adiabatic expansion of the gas in the chamber 11. However, if the volume of the upper stage 12 is larger than that of the lower stage 13 (however, the material is the same), the upper stage 12 was at the same temperature before the start of decompression due to the difference in heat capacity between the upper and lower stages 12 and 13. And a lower stage 13, a temperature difference occurs between the upper and lower substrates 1 and 2 held in close contact with the upper and lower stages 12 and 13, and as shown in FIG. A difference in shrinkage occurs. As the temperature in the chamber 11 decreases, the upper and lower stages 12 and 13 start to dissipate heat, but the lower stage 13 having a smaller volume and a smaller heat capacity has a lower temperature than the upper stage 12 having a larger volume and a larger heat capacity. fast. Therefore, the temperature of the lower substrate 2 held on the lower stage 13 having a small heat capacity is lower than that of the upper substrate 1 held on the upper stage 12 having a large heat capacity. In the process of lowering, the length of the lower substrate 2 in the surface direction is shortened.

The difference in shrinkage between the upper and lower substrates 1 and 2 affects the bonding accuracy of the upper and lower substrates 1 and 2. When the length of one side becomes a 3m class substrate, if the temperature difference between the upper and lower substrates 1 and 2 is 1 ° C, the upper and lower substrates 1 and 2 may be displaced relative to each other in a plane direction of 10μm or more. This greatly exceeds the allowable value of 1 μm for the relative displacement between the upper and lower substrates 1 and 2. In addition, in the case of a liquid crystal display panel in which one of the upper and lower substrates 1 and 2 is a TFT substrate and the other is a color filter substrate, a relative positional shift occurs in the plane direction between the pixel electrode on the TFT substrate side and the color filter. Then, uneven color occurs.
JP2000-66163

  It is an object of the present invention to prevent a difference in expansion and contraction between the upper and lower substrates held on the upper and lower stages due to a temperature difference between the upper and lower stages when the chamber is decompressed to a vacuum state. Accordingly, it is an object of the present invention to provide a substrate bonding apparatus and a substrate bonding method capable of preventing a relative positional shift in the surface direction of the upper and lower substrates.

The present invention includes a vacuum chamber having a substrate loading / unloading port;
An upper stage and a lower stage provided in the vacuum chamber;
A moving device for relatively moving the upper stage and the lower stage in the vertical direction;
A decompression device for decompressing the inside of the vacuum chamber;
A gas supply source for supplying gas into the vacuum chamber;
And a control device for controlling said gas supply source and the mobile device and the decompression device,
The upper substrate supplied from the loading / unloading exit and held on the upper stage and the lower substrate held on the lower stage are bonded together in a state where the vacuum chamber is decompressed by the decompression device , and then In the substrate bonding apparatus in which the gas is supplied from the gas supply source into the vacuum chamber and the pressure is increased ,
When the controller controls the decompression device to decompress the inside of the vacuum chamber to a predetermined pressure, the control device controls the moving device to determine the interval between the opposing surfaces of the upper stage and the lower stage and the upper substrate. When the pressure is increased by supplying gas from the gas supply source into the vacuum chamber that is set to be smaller than the interval between the opposing surfaces when the lower substrate is supplied to the lower stage on the upper stage. The moving device is controlled so that the interval between the opposed surfaces of the upper stage and the lower stage is set to the same interval as that set when the inside of the vacuum chamber is depressurized .

The present invention relates to an upper substrate which is supplied from the carry-in / out port and held on the upper stage by relatively moving an upper stage and a lower stage provided in a vacuum chamber having a substrate carry-in / out port. And a lower substrate held on the lower stage, in a state of depressurizing the inside of the vacuum chamber, after that, in the substrate laminating method formed by increasing the pressure in the vacuum chamber,
When reducing the pressure within the vacuum chamber to a predetermined pressure, the distance between the opposing surfaces of the lower stage and the upper stage, the substrate on said stage, when supplying, respectively it the lower substrate to the lower stage When the pressure inside the vacuum chamber is increased, the distance between the opposing surfaces of the upper stage and the lower stage is set to the same interval as that set when the pressure in the vacuum chamber is reduced. in which it was to be set.

  According to the present invention, the interval between the opposing surfaces of the upper stage and the lower stage in the chamber is smaller than the interval between the opposing surfaces when the upper substrate and the lower substrate are supplied to the upper stage and the lower stage, respectively. Therefore, the radiant heat emitted from the upper and lower stages is transmitted to each other through the space between the upper and lower substrates, and the temperature difference generated between the upper and lower substrates can be suppressed. As a result, it is possible to prevent the occurrence of relative positional deviation in the surface direction of the upper and lower substrates due to the temperature difference, thereby improving the bonding accuracy of the substrates.

  FIG. 1 is a schematic diagram showing a substrate bonding apparatus at the time of decompression in the chamber, FIG. 2 is a schematic diagram for explaining the operation of the substrate bonding apparatus in FIG. 1, and FIG. FIG. 4 is a graph showing the temperature change of the upper and lower substrates in this example, and FIG. 5 is a schematic diagram showing the substrate bonding apparatus at the time of pressure increase in the chamber.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The configurations described in the background art using FIG. 7 are assigned the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIG. 1, the substrate bonding apparatus 10 includes a chamber 11 that is integrally formed in a box shape. The chamber 11 opens and closes a loading / unloading port 21 for loading and unloading a substrate, and opening / closing the loading / unloading port 21. A shutter 22 is provided on one side. From the loading / unloading exit 21 of the chamber 11, the substrates 1 and 2 held by suction on the arm 23 of the transfer robot are carried into and out of the chamber 11.

  The upper and lower stages 12 and 13 are each formed of a rectangular disk and are made of the same aluminum alloy. In this embodiment, the upper stage 12 is thicker and larger in volume than the lower stage 13. The substrates 1 and 2 are rectangular glass substrates.

  The substrate bonding apparatus 10 includes a vertical movement device 14 that moves the upper stage 12 in the vertical direction. The vertical movement device 14 is provided on the upper wall of the chamber 11 and is connected to the upper stage 12 via a connecting rod 14A. The connection rod 14A and the upper wall of the chamber 11 are kept airtight by an airtight member (not shown). The vertical movement device 14 moves the connecting rod 14A up and down by a ball screw mechanism driven by a drive source such as a motor. The upper stage 12 has an upper substrate suction means (not shown) such as an electrostatic suction board or a vacuum suction board made up of a plurality of suction holes connected to a vacuum source (not shown) on the lower surface.

  A lower substrate suction means (not shown) such as a vacuum suction disk composed of a plurality of suction holes connected to a vacuum source is provided on the upper surface of the lower stage 13, and the lower substrate 2 is placed on the upper surface of the lower stage 13 by the lower substrate suction means. Adsorb to.

In addition, a plurality of lift pins (not shown) are provided on the upper surface of the lower stage 13 so as to appear and retract.
The lower stage 13 is provided so as to be able to move horizontally and turn by a horizontal movement device 15 comprising an XY table (not shown) and a θ rotation mechanism.

  The substrate bonding apparatus 10 is connected to a decompression device 16 comprising a vacuum pump, a gas supply source 17 for supplying a gas such as nitrogen gas or dry air, and the decompression device 16 and the gas supply source 17 in the chamber 11. A conduit 35 and a switching valve 36 interposed in the conduit 35 are provided. The switching valve 36 is connected to the decompression device 16 side to evacuate the chamber 11, and the atmosphere inside the chamber 11 is decompressed to a vacuum state, and the chamber 11 is connected to the gas supply source 17 side to connect nitrogen gas. Alternatively, dry air or the like is introduced, and the atmosphere in the chamber 11 in a vacuum state is switched to a state where the pressure is increased to atmospheric pressure. 18 is an on-off valve.

  A vacuum sensor 24 for detecting the degree of vacuum in the chamber 11 is attached to the chamber 11.

  The substrate bonding apparatus 10 includes an imaging device 20 formed of a CCD camera, camera moving means 20A, and an image processing device (not shown) for processing an image captured by the imaging device 20. Position detection marks for positioning the upper and lower substrates 1 and 2 in the surface direction are attached to the four corner portions of the bonding surfaces of the upper and lower substrates 1 and 2 facing each other.

  The imaging device 20 comprising a CCD camera images these position detection marks, corresponding to the four corners of the upper substrate 1 attracted and held by the upper stage 12 and the lower substrate 2 attracted and held by the lower stage 13. , One at a time below the chamber 11. Corresponding to the imaging device 20, a viewing window 11 </ b> A is provided in the chamber 11, a through hole 32 is provided in the lower stage 13, and a through hole 33 is provided in the upper stage 12. The imaging device 20 images the position detection marks on the upper substrate 1 and the lower substrate 2 through the viewing window 11A and the through hole 32 of the lower stage 13. A light source 34 is provided above the through-hole 33 of the upper stage 12 so as to face the imaging device 20, and the position detection marks on the upper substrate 1 and the lower substrate 2 are respectively captured as silhouette images.

  The imaging device 20 is provided so as to be movable up and down by the camera moving means 20A in order to put the alignment marks attached to the four corners of the upper and lower substrates 1 and 2 within the depth of focus.

  The image processing apparatus processes the image captured by the imaging apparatus 20 and detects a positional deviation in the surface direction between the alignment mark on the upper substrate 1 and the alignment mark on the lower substrate by pattern matching processing. The control device drives the horizontal movement device 15 so as to eliminate this positional shift, moves the lower substrate 2 in the surface direction with respect to the upper substrate 1, and aligns the upper substrate 1 and the lower substrate 2.

  The substrate laminating device 10 is controlled by a control device 25 in a vertical movement device 14, a horizontal movement device 15, a switching valve 36, a decompression device 16, a gas supply source 17, an imaging device 20, a camera moving means 20A, and image processing. By controlling the apparatus and the like, the upper substrate 1 and the lower substrate 2 are bonded together as follows.

  (1) Of the upper and lower substrates 1 and 2, first, the upper substrate 1 is sucked and held on the arm 23 of the transfer robot, and is transferred from the loading / unloading port 21 of the chamber 11 to a position facing the lower surface of the upper stage 12.

  (2) The vertical movement device 14 is driven to lower the upper stage 12, and the upper substrate 1 is sucked and held by the upper substrate suction means on the lower surface of the upper stage 12. If the upper substrate 1 is held by suction, the upper stage 12 is raised to the original position. Thereafter, the arm 23 of the transfer robot is retracted from the chamber 11.

  (3) The lower substrate 2 is sucked and held on the arm 23 of the transfer robot, is loaded from the loading / unloading port 21 of the chamber 11 to a position facing the upper surface of the lower stage 13, and the arm 23 is lowered to protrude from the lower stage 13. Place on the lift pins. Thereafter, the arm 23 is retracted from the chamber 11. Next, the lift pins are lowered, and the lower substrate 2 is sucked and held on the upper surface of the lower stage 13 by the lower substrate sucking means.

  Here, the lower substrate 2 supplied to the lower stage 13 is coated with a sealing agent in a frame shape, and liquid crystal is dropped in a region surrounded by the sealing agent.

  The process up to the above step (3) is the same as that in the background art. However, in the case of the background art, in the step (4), the interval between the opposing surfaces of the upper stage 12 and the lower stage 13 in the chamber 11 is increased. The inside of the chamber 11 is depressurized while maintaining the distance D1 when the upper substrate 1 and the lower substrate 2 are supplied onto the stage 12 and the lower stage 13, but in this embodiment, this is performed as follows.

  (4) Before starting the decompression in the chamber 11, first, the vertical movement device 14 is driven, and the upper stage 12 is lowered from the state when the upper and lower substrates 1 and 2 are supplied to the upper and lower stages 12 and 13. The interval between the opposing surfaces of the upper stage 12 and the lower stage 13 in the chamber 11 is smaller than the interval D1 when the upper substrate 1 and the lower substrate 2 are supplied onto the upper stage 12 and the lower stage 13, respectively. D2 (hereinafter, simply referred to as “small interval D2”). In this embodiment, the distance between the opposed surfaces of the upper and lower stages 12 and 13 is set to about 5 mm.

  (5) Next, the shutter 22 of the chamber 11 is closed, the switching valve 36 of the pipe line 35 is connected to the decompression device 16 side, and the decompression device 16 is driven so that the inside of the chamber 11 is a predetermined pressure required for bonding, for example, , Start depressurization toward 1 Pa. In step (5), the switching valve 36 is positioned on the gas supply source 17 side and the on-off valve 18 is closed until the decompression of the chamber 11 is started.

  In step (5), the temperature of the upper and lower substrates 1 and 2 is assumed to be substantially the same as the atmospheric temperature at the atmospheric pressure when the pressure reduction in the chamber 11 is started.

  Here, the shutter 22 is provided until the supply of the upper and lower substrates 1 and 2 to the upper and lower stages 12 and 13 is completed and the arm 23 is retracted from the chamber 11 and then decompression in the chamber 11 is started. Therefore, it may be performed between step (3) and step (4) or in parallel with step (4). When the inside of the chamber 11 is depressurized to a vacuum state, the gas in the chamber 11 is cooled by adiabatic expansion, so that the ambient temperature in the chamber 11 decreases. As a result, the upper and lower stages 12 and 13 gradually start to dissipate heat, and the temperature of the upper and lower stages 12 and 13 opens the shutter 22 and supplies the upper substrate 1 and the lower substrate 2 on the upper stage 12 and the lower stage 13, respectively. It approaches the atmospheric temperature in the chamber 11 from the temperature at the time.

  The control device controls the vertical movement device 14, the switching valve 36, and the decompression device 16, and sets the distance between the opposing surfaces of the upper stage 12 and the lower stage 13 in the chamber 11, and sets the upper substrate 1 and the lower substrate 2 to the upper stage, respectively. Since the inside of the chamber 11 is depressurized at an interval D2 that is smaller than the interval D1 when it is supplied onto the upper stage 12 and the lower stage 13, the heat released from one of the upper and lower stages 12, 13 is The other stage is transmitted as radiant heat through the space between the stages 12 and 13 and affects each other. At this time, the material of the upper stage 12 and the lower stage 13 is the same, the volume of the upper stage 12 is larger than that of the lower stage 13, and the heat capacity of the upper stage 12 is larger than that of the lower stage 13. The heat energy is larger than the radiant heat of the stage 13.

  Thus, since the radiant heat emitted from one stage 12 (13) is transmitted to the other stage 13 (12), the temperatures of the upper stage 12 and the lower stage 13 are averaged, and the upper and lower stages 12, The occurrence of 13 temperature differences is suppressed. As a result, the occurrence of a temperature difference between the upper and lower substrates 1 and 2 held by suction on the upper and lower stages 12 and 13 is suppressed, and the upper and lower substrates 1 and 2 caused by the difference in shrinkage between the upper and lower substrates 1 and 2 are suppressed. Occurrence of relative displacement in the surface direction is prevented. The radiant heat of the upper and lower stages 12 and 13 is directly transmitted to the upper and lower substrates 1 and 2 facing each other through the space between the upper and lower stages 12 and 13.

  FIG. 4 is a graph in which a temperature sensor (not shown) is attached in the chamber 11 and the change in the atmospheric temperature in the chamber 11 during decompression is measured. The horizontal axis represents time, and the vertical axis represents temperature. In the figure, CH1 indicated by the broken line is 10 mm from the stage 12, 13 end, CH2 indicated by the alternate long and short dash line is the stage 12, 20 mm from the 13 end, and CH3 indicated by the solid line is the temperature attached at an interval of 30 mm from the stage 12, 13 end. It represents a change in the atmospheric temperature in the chamber 11 when measured by a sensor.

  Also, in the graph, the symbol a attached to the horizontal axis is the pressure reduction start time in the chamber 11, the symbol b is the time when the ambient temperature at the position 30 mm from the ends of the stages 12 and 13 reaches the minimum temperature, and the symbol c is the stage. When the atmospheric temperature at a position 10 mm from the ends of 12 and 13 reaches the minimum temperature, symbol d indicates when the supply of nitrogen or dry air into the decompressed chamber 11 is started, and symbol e indicates that the pressure in the chamber 11 is large. The point in time when the pressure returned to atmospheric pressure is shown.

  In the solid line CH3 when the temperature sensor is positioned at a distance of 30 mm farthest from the ends of the stages 12 and 13, the measured temperature of the temperature sensor is abruptly immediately after the start of pressure reduction a. It begins to drop and reaches a minimum temperature of about 13 ° C. at a subsequent time point b. The temperature measured by the temperature sensor at this time is lowered because the gas in the chamber 11 is cooled by adiabatic expansion of the gas in the chamber 11.

  Thereafter, in a state where the inside of the chamber 11 is maintained in a predetermined vacuum state until time point d, the measurement temperature of the temperature sensor rises gradually, and the measurement temperature rises from about 13 ° C. to about 19 ° C. The rise in the measured temperature at this time is due to the temperature sensor being warmed by the radiant heat emitted from the upper and lower stages 12 and 13.

  Next, in the broken line CH1 when measured at a distance of 10 mm closest from the ends of the stages 12 and 13, the measured temperature of the temperature sensor starts to decrease abruptly immediately after the pressure reduction start point a as in CH3. The curve becomes gentle from the middle of the decrease, and reaches a minimum temperature of about 15 ° C. at time point c. Accordingly, the temperature drop of the broken line CH1 is smaller and smaller than that of the solid line CH3. The temperature drop of the broken line CH1 is more gradual and smaller than the solid line CH3. The broken line CH1 is emitted from the stages 12 and 13 because the temperature sensor is mounted closer to the stages 12 and 13 than the solid line CH3. By being strongly affected by radiant heat.

Thereafter, as in the case of CH 3, the atmospheric temperature gradually rises in a state where the chamber 11 is maintained in a predetermined vacuum state, and rises to about 21 ° C. until time point d. In this case, the reason why the temperature rise is about 2 ° C. higher than that of CH 3 is that the influence of the radiant heat of the stages 12 and 13 is large because the distance from the ends of the stages 12 and 13 is short.
The alternate long and short dash line CH2 indicates a temperature change between the solid line CH3 and the broken line CH1.

  As described above, the graph of FIG. 4 shows that radiant heat is released from the upper and lower stages 12 and 13 during the temperature drop in the chamber 11 and in a state where the vacuum is maintained thereafter.

  Further, from the result of CH3, it is shown that the temperature sensor is warmed by radiant heat even when the temperature sensor is measured at the distance of 30 mm farthest from the ends of the stages 12 and 13 and the ambient temperature in the chamber 11 is measured. . Accordingly, it is preferable that the distance D2 between the opposing surfaces of the upper and lower stages 12, 13 is as small as possible, but the distance is not necessarily small. That is, when one of the upper and lower stages 12 and 13 applies radiant heat to the other stage, the occurrence of a temperature difference between the upper and lower stages 12 and 13 due to the reduced pressure in the chamber 11 is suppressed. Any spacing that can suppress the occurrence of relative positional deviation in the surface direction due to the difference in contraction between the upper and lower substrates 1 and 2 may be used.

  (6) If it is detected by the detection signal from the pressure detector 24 that the atmospheric pressure in the chamber 11 has reached a predetermined pressure, the vertical movement device 14 is driven to move the upper stage 12 to the chamber 11. From the position when the inside is reduced to a vacuum state, the upper and lower substrates 1 and 2 are further lowered to the position when the relative alignment is performed in the surface direction.

  Next, the alignment mark of the upper substrate 1 and the lower substrate 2 is imaged by the imaging device 20, the captured image is image-processed by an image processing device (not shown), and the surfaces of the upper substrate 1 and the lower substrate 2 are subjected to pattern matching processing. Detects the relative displacement state in the direction. Then, the horizontal movement device 15 is driven so as to eliminate this relative positional shift, the lower substrate 2 is moved in the surface direction, and the upper substrate 1 and the lower substrate 2 are aligned.

  (7) The vertical movement device 14 is driven to pressurize the upper and lower substrates 1 and 2 so that the upper substrate 1 and the lower substrate 2 are bonded together with a sealant, and as shown in FIG. A bonded substrate 40 having a sealed space between the sealing agent and the sealing agent is prepared. By bonding under reduced pressure by the decompression device 16, it is possible to avoid air from being mixed into the liquid crystal dripped onto the lower substrate 2.

  (8) As shown in FIG. 5, suction of the upper substrate 1 by the upper substrate suction means of the upper stage 12 is released, and the upper stage 12 is raised by driving the vertical movement device 14. Then, a gap C is provided between the upper surface of the upper substrate 1 and the lower surface of the upper stage 13 so that the upper stage 12 and the lower stage 13 in the chamber 11 face each other in the same manner as at the time of decompression in the step (4). The interval between the surfaces is defined as an interval D2 that is smaller than the interval D1 when the upper substrate 1 and the lower substrate 2 are supplied to the upper stage 12 and the lower stage 13, respectively.

  A gap C is provided between the upper surface of the upper substrate 1 and the lower surface of the upper stage 13 so that the distance between the opposing surfaces of the upper and lower stages 1 and 2 is set to a small distance D2. While connecting to the gas supply source 17 side and opening the on-off valve 18, nitrogen or dry air is introduced into the chamber 11 to increase the pressure to atmospheric pressure, and the upper and lower substrates 1, 2 are pressurized by atmospheric pressure to cause the upper and lower substrates 1, 2 to be pressurized. They are bonded together so that a predetermined gap is formed between them.

  Here, when the pressure inside the decompressed chamber 11 is increased to the atmospheric pressure, the atmospheric temperature in the chamber 11 is increased by the heat of the gas supplied into the chamber 11 as opposed to when the pressure inside the chamber 11 is decompressed. To do.

  In the graph of FIG. 4, dry air having a temperature of about 30 ° C. was supplied into the chamber 11 from the time point d to the time point e.

  According to the graph of FIG. 4, the temperature measured by the temperature sensor at any position begins to rise rapidly from the time point d at which dry air begins to be supplied into the chamber 11, and reaches a maximum during the time point e until the atmospheric pressure is reached. The temperature reaches the temperature, and at a timing slightly delayed from the time point e, the temperature returns to substantially the same as the temperature before the start of decompression. Further, the temperature change becomes gentler and smaller as the distance from the ends of the stages 12 and 13 is shorter. This indicates that the closer the distance from the ends of the stages 12 and 13 is, the easier the stages 12 and 13 are deprived of heat.

  Thus, the upper stage 12 was introduced between the lower surface of the upper stage 12 and the upper surface of the upper substrate 1 by setting the distance between the opposing surfaces of the upper stage 12 and the lower stage 13 to a small distance D2. Since the heat of the gas is taken away, the temperature rise of the upper surface of the upper substrate 1 is suppressed, and thereby the occurrence of the temperature difference between the upper and lower substrates 1 and 2 in the bonded substrate 40 is suppressed. As a result, the upper substrate 1 is prevented from stretching when the pressure in the chamber 11 is increased, and the occurrence of relative positional deviation in the plane direction of the upper and lower substrates 1 and 2 of the bonded substrate 40 is prevented. Thereby, the upper and lower substrates 1 and 2 can be bonded together with high accuracy.

  Further, when the interval D2 between the opposed surfaces of the upper stage 12 and the lower stage 13 is set to a small interval D2, it is better to set the interval D2 in the small state before starting the pressure increase in the chamber 11. When the pressure in the chamber 11 is increased in a state where the upper stage 12 is in contact with the upper substrate 1 of the bonded substrate 40, a vacuum space (in the pressurized chamber 11 is formed in a minute gap between the lower surface of the upper stage 12 and the upper surface of the upper substrate 1. This is because the upper substrate 1 is in close contact with the upper stage 12 due to the pressure difference between them.

  When the upper stage 12 is raised while the upper substrate 1 is in close contact with the upper stage 12, a force in the direction of separating from the lower substrate 2 held by the lower stage 13 acts on the upper substrate 1, and in step (7) A gap may be formed between the contacted upper substrate 1 and the sealant. When such a gap is generated, a gas enters the space surrounded by the upper and lower substrates 1 and 2 and the sealing agent, or the liquid crystal leaks out, causing a defect.

  As described above, the occurrence of such a defect can be prevented by separating the upper stage 12 from the upper substrate 1 before starting the pressure increase in the chamber 11.

  (9) The vertical movement device 14 is driven to raise the upper stage 12 to a position where the interstitial surface of the upper and lower stages 12 and 13 faces the distance D1. Next, suction of the lower substrate 2 by the lower substrate suction means of the lower stage 13 is released, and thereafter, lift pins (not shown) protrude from the lower stage 13 to lift the bonded substrate 40 from above the lower stage 13. Thereafter, the on-off valve 8 is closed, the shutter 22 of the chamber 11 is opened, the arm 23 of the transfer robot is advanced into the chamber 11, and the bonded substrate 40 placed on the lift pins of the lower stage 13 is viewed from below. It is sucked and held and carried out from the carry-in / out port 21 of the chamber 11.

  FIG. 5 is a graph in which the surface temperature of the upper and lower substrates 1 and 2 is measured with the distance D2 between the opposing surfaces of the upper and lower stages 12 and 13 set to about 5 mm. In the graph, the symbol a indicates the time point when the pressure reduction in the chamber 11 starts, and the symbol e indicates the time point when the pressure inside the reduced pressure chamber 11 returns to atmospheric pressure. As shown in the graph, the surface temperatures of the upper and lower substrates 1 and 2 are maintained at about 23 ° C. from the time point a to the time point e. can not see.

  Note that the shrinkage of the substrates 1 and 2 with respect to the temperature change (elongation at the time of pressurization) increases as the size of the substrates 1 and 2 increases with the same material. If the material of the substrates 1 and 2 is the same, the smaller distance D2 between the upper and lower stages 11 and 12 is preferably reduced as the size of the substrates 1 and 2 increases.

  In addition, the shrinkage and elongation of the substrates 1 and 2 with respect to the temperature change increase as the thermal expansion coefficient of the substrates 1 and 2 increases as long as the substrates 1 and 2 have the same size. In this case, the smaller distance D2 between the upper and lower stages 12, 13 is preferably smaller as the thermal expansion coefficient of the substrates 1, 2 is larger.

According to the present embodiment, the following operational effects can be obtained.
(a) When the pressure in the chamber 11 is reduced, the atmospheric temperature in the chamber 11 is lowered due to the adiabatic expansion of the gas in the chamber 11. At this time, if the upper and lower stages 12 and 13 formed of the same material have different volumes, the heat capacities of the upper and lower stages 12 and 13 are different. Therefore, they are held on the upper and lower stages 12 and 13 due to the difference in heat capacity. A temperature difference occurs between the substrates 1 and 2.

  According to the present embodiment, when the inside of the chamber 11 is depressurized, the distance between the opposing surfaces of the upper stage 12 and the lower stage 13 in the chamber 11 is changed to the upper stage 12 and the lower stage 13 respectively. Since the distance D2 is smaller than the distance D1 between the opposing surfaces when supplying, the radiant heat emitted from the upper and lower stages 12, 13 influence each other, and the temperatures of the upper and lower stages 12, 13 are averaged. Therefore, the generation of the temperature difference between the upper and lower stages 12 and 13 is suppressed, and the generation of the temperature difference between the upper and lower substrates 1 and 2 held on the upper and lower stages 12 and 13 can be suppressed. As a result, it is possible to prevent the occurrence of relative positional deviation in the surface direction of the upper and lower substrates 1 and 2 due to the temperature difference, thereby preventing the bonding accuracy of the substrates 1 and 2 from being lowered. Therefore, the quality of the manufactured liquid crystal display panel can be improved.

  (b) Although the decrease in the atmospheric temperature in the chamber 11 starts simultaneously with the pressure reduction, according to the present embodiment, the interval between the facing surfaces of the upper stage 12 and the lower stage 13 is made small before the pressure reduction in the chamber 11 is started. Since the state interval D2 is set, the upper and lower substrates 1 and 2 are affected by the radiant heat of the upper and lower stages 12 and 13 from the beginning when the atmospheric temperature in the chamber 11 starts to decrease. The occurrence of this temperature difference can be reliably suppressed. Thereby, the fall of the bonding precision of the upper board | substrate 1 and the lower board | substrate 2 can be prevented.

  (c) After the upper substrate 1 and the lower substrate 2 are bonded together in a state where the inside of the chamber 11 is depressurized to a vacuum state, when the pressure inside the chamber 11 is increased, the interval between the opposing surfaces of the upper stage 12 and the lower stage 13 is The interval D2 is smaller than the interval D1 when the upper substrate 1 and the lower substrate 2 are supplied to the upper stage 12 and the lower stage 13, respectively. As a result, the upper stage 12 deprives the heat of the gas that has entered between the upper stage 12 and the upper surface of the upper substrate 1, so that the temperature rise on the upper surface of the upper substrate 1 is suppressed. It is possible to prevent the occurrence of relative displacement in the surface direction of the upper and lower substrates 1 and 2 at 40.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, in the present embodiment, the case where the heat capacities of the upper and lower stages are different due to the difference in volume between the upper and lower stages has been described.However, in the present invention, one of the upper and lower stages has a heat source such as a motor, In general, the present invention can be applied even when the thermal environment of the upper and lower stages is different, such as when a temperature difference occurs between the upper and lower stages because the stage is provided closer to the heat source than the other stage.

  Further, in this embodiment, before starting the decompression in the chamber, the interval between the opposing surfaces of the upper and lower stages in the chamber is set to be smaller than the interval when the upper and lower substrates are supplied to the upper and lower stages, respectively. However, the interval between the opposing surfaces of the upper and lower stages in the middle of the decompression in the chamber may be smaller than the interval when each substrate is supplied.

  In this embodiment, the upper stage has a larger volume than the lower stage, but the lower stage may have a larger volume than the upper stage.

It is a schematic diagram which shows the board | substrate bonding apparatus at the time of pressure reduction in a chamber. It is a schematic diagram for demonstrating an effect | action of the board | substrate bonding apparatus of FIG. It is a graph showing the result of having measured the temperature change of the atmosphere in a chamber, changing the distance from a stage. It is a graph showing the temperature change of the upper and lower substrates in a present Example. It is a schematic diagram which shows the board | substrate bonding apparatus at the time of the pressure | voltage rise in a chamber. It is a schematic diagram which shows the board | substrate bonding apparatus at the time of the pressure reduction in the chamber in background art. It is a schematic diagram for demonstrating an effect | action of the board | substrate bonding apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper board | substrate 2 Lower board | substrate 10 Board | substrate bonding apparatus 11 Chamber 12 Upper stage 13 Lower stage 14 Vertical movement apparatus 16 Decompression apparatus 21 Opening and closing opening D1, D2 The space | interval of the opposing surface of an upper and lower stage

Claims (4)

A vacuum chamber having a substrate loading / unloading port;
An upper stage and a lower stage provided in the vacuum chamber;
A moving device for relatively moving the upper stage and the lower stage in the vertical direction;
A decompression device for decompressing the inside of the vacuum chamber;
A gas supply source for supplying gas into the vacuum chamber;
And a control device for controlling said gas supply source and the mobile device and the decompression device,
The upper substrate supplied from the loading / unloading exit and held on the upper stage and the lower substrate held on the lower stage are bonded together in a state where the vacuum chamber is decompressed by the decompression device , and then In the substrate bonding apparatus in which the gas is supplied from the gas supply source into the vacuum chamber and the pressure is increased ,
When the controller controls the decompression device to decompress the inside of the vacuum chamber to a predetermined pressure, the control device controls the moving device to determine the interval between the opposing surfaces of the upper stage and the lower stage and the upper substrate. When the pressure is increased by supplying gas from the gas supply source into the vacuum chamber that is set to be smaller than the interval between the opposing surfaces when the lower substrate is supplied to the lower stage on the upper stage. The substrate bonding apparatus , wherein the distance between the opposing surfaces of the upper stage and the lower stage is controlled to be the same as the distance set when the inside of the vacuum chamber is depressurized by controlling the moving device. 2. The substrate bonding apparatus according to claim 1, wherein the control device controls the moving device to reduce an interval between opposing surfaces of the upper stage and the lower stage before starting the pressure reduction in the vacuum chamber. . An upper stage and a lower stage, which are respectively supplied from the carry-in / out opening and held on the upper stage by relatively moving an upper stage and a lower stage provided in a vacuum chamber having a carry-in / out opening of the substrate In the substrate bonding method in which the lower substrate held in the vacuum chamber is bonded in a state where the vacuum chamber is decompressed, and then the pressure in the vacuum chamber is increased .
When the inside of the vacuum chamber is depressurized to a predetermined pressure, the interval between the opposing surfaces of the upper stage and the lower stage is set such that the upper substrate is supplied to the upper stage and the lower substrate is supplied to the lower stage. When the pressure inside the vacuum chamber is set to be smaller than the interval between the opposing surfaces, the interval between the opposing surfaces of the upper stage and the lower stage is set to the same interval as that set when the pressure in the vacuum chamber is reduced. A substrate bonding method characterized by that. The substrate bonding method according to claim 3 , wherein an interval between opposing surfaces of the upper stage and the lower stage is reduced before starting the pressure reduction in the vacuum chamber.

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