JP2000284295A - Method and apparatus for assembling substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bond substrates which are approximately the same to each other with high accuracy in a vacuum even if the substrate size increases and the thickness thereof is reduced. SOLUTION: Electrostatic attraction force is acted on an upper substrate 1b from a pressurizing plate 27 and the upper substrate 1b is held on the pressurizing plate 27 and is bonded thereto in the vacuum. Further, the upper substrate 1b is held on the pressurizing plate 27 by suction attraction force and the electrostatic attraction force is acted on the upper substrate 1b accepted in the position of the extent slight apart from the pressurizing plate 27 dropped when the suction attraction force disappears in the process of progressing the pressure reduction, by which the upper substrate 1b is again held on the pressurizing plate 27 and the bonding in the vacuum is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for assembling substrates to be bonded in a vacuum chamber while holding and opposing the substrates to be bonded to each other and narrowing the gap in a vacuum.

[0002]

2. Description of the Related Art In manufacturing a liquid crystal display panel, an adhesive (hereinafter, referred to as a glass substrate) having two glass substrates provided with a transparent electrode and a thin film transistor array at an extremely close interval of about several micrometers.
There is a step of bonding together (hereinafter, the substrate after bonding is called a cell) by sealing with a liquid crystal in a space formed by the bonding.

In order to seal the liquid crystal, the liquid crystal is dropped on one of the substrates in which a sealing agent is drawn in a closed pattern so that no injection port is provided, and the other substrate is disposed on the one of the substrates. A method proposed in Japanese Patent Application Laid-Open No. 62-165622, in which the upper and lower substrates are brought close together in a vacuum,
There is a method proposed in Japanese Patent Application Laid-Open No. Hei 10-26763 in which a pattern is drawn on a sealant so as to provide an injection port on one of the substrates, and the substrates are bonded in a vacuum and then injected from the injection port of the sealant.

[0004]

In the above prior art, both substrates are bonded in a vacuum regardless of before and after the pattern drawing of the sealant. In a vacuum, the substrate cannot be suction-adsorbed due to a pressure difference from the atmosphere as in the atmospheric state.

When the edge of a substrate located above (hereinafter referred to as an upper substrate) is mechanically held, the central portion of the substrate bends, and the deflection increases with the recent tendency of the substrate to become larger and thinner. ing.

Since the positioning is performed by using the alignment marks provided on the peripheral edges of the upper and lower substrates, the larger the deflection, the wider the distance between the ends of the two substrates and the more the alignment becomes impossible.

Further, the lower substrate (hereinafter, referred to as the lower substrate) has a central portion of the upper substrate which is bent before the peripheral portion due to the deflection of the upper substrate.
Therefore, the spacers scattered between the substrates move in order to keep the distance between the substrates constant, thereby damaging the alignment film and the like formed on the substrates.

Actually, since the upper and lower substrates to be bonded are the same size, the holding margin is hardly removed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for assembling a substrate capable of bonding substrates of the same degree with high precision in a vacuum even if the substrate size is increased and thinned. It is in.

[0010]

The feature of the present invention to achieve the above object is to apply an electrostatic attraction force from the pressing plate to the upper substrate to hold the upper substrate on the pressing plate and to adhere the substrate in a vacuum. The point is to make adjustments.

Further, the upper substrate is held on the pressure plate by suction attraction in the atmosphere, and the upper substrate which falls when the suction attraction disappears in the process of decompression is moved to a position slightly away from the pressure plate. Then, an electrostatic attraction force is applied to the upper substrate from the pressing plate, and the upper substrate is again held by the pressing plate to perform bonding in a vacuum.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

1 to 3, the substrate assembling apparatus according to the present invention comprises a liquid crystal dropping part S1 and a substrate bonding part S2, and these two parts are arranged adjacent to each other on the gantry 2. Above the gantry 2, there is a frame 3 that supports the substrate bonding portion S2. An XYθ stage T1 is provided on the upper surface of the gantry 2. The X stage 4a is driven by the drive motor 5 in the left and right X-axis directions on the drawing, that is, the liquid crystal dropping portion S1.
And the substrate bonding portion S2. Y
The stage 4b is on the X stage 4a, and can be moved by the drive motor 6 in the Y-axis direction orthogonal to the X stage. θ stage 4c is on Y stage 4b,
A table 9 on which a substrate is mounted is fixed on the θ stage 4c so as to be rotatable horizontally with respect to the Y stage 4b by a drive motor 8 via a rotary bearing 7. The lower chamber 10 is fixed to the Y stage 4b by a plate 13. stage 4c is connected to the lower chamber 10 via a rotary bearing 11 and a vacuum seal
Can be freely rotated about the center of rotation
Even if c rotates, the lower chamber 10 is suspended and does not rotate.

The liquid crystal dropping section S1 is provided with a dispenser 17 supported by a bracket 14 protruding from the frame 3 for dropping a desired amount of liquid crystal agent onto the lower substrate 1a held on the table 9, and for moving the dispenser 17 up and down. Z axis stage 1
5 and a motor 16 for driving the same. Lower substrate 1
XYθ stage T1 holding a mounted on table 9
Moves in the X and Y directions with respect to the nozzle 18 of the dispenser 17 for dropping the liquid crystal agent. Thereby, the lower substrate 1
A desired amount of liquid crystal agent is dropped at an arbitrary position on a.

X holding the lower substrate 1a after dropping the liquid crystal
The Yθ stage T1 is moved by the drive motor 5 below the substrate bonding portion S2.

The substrate bonding portion S2 has a structure in which the upper chamber 21 and the electrostatic attraction plate 28 therein can move up and down independently of each other. That is, the upper chamber 21 has a housing 30 containing a linear bush and a vacuum seal, and is moved in the vertical Z-axis direction by a cylinder 22 fixed to the frame 2 using the shaft 29 as a guide.

When the XYθ stage T1 is moved to the substrate bonding portion S2 and the upper chamber 21 is lowered, the lower chamber 1
O-ring 44 disposed around the upper chamber 21
Are brought into contact with each other and become integral with each other, and at this time, a state of functioning as a vacuum chamber is established.

The amount of collapse of the O-ring 44 depends on the upper chamber 2
The lowering stop position is adjusted so that the inside of the vacuum chamber can be kept at a vacuum and the maximum elasticity can be obtained.

The housing 30 has a built-in vacuum seal that can move up and down without causing a vacuum leak to the shaft 29 even if the upper chamber 21 forms a vacuum chamber with the lower chamber 10 and deforms. The deformation of the chamber can absorb the force applied to the shaft 29, and the deformation of the pressure plate 27 fixed to the shaft 29 and holding the electrostatic attraction plate 28 can be substantially prevented, and can be held at the electrostatic attraction plate 28 as described later. The bonded upper substrate 1b and the lower substrate 1a held on the table 9 can be bonded while maintaining the parallelism.

Reference numeral 23 denotes a vacuum valve, and reference numeral 24 denotes a piping hose connected to a vacuum source (not shown), and these are used when the vacuum chamber is depressurized and evacuated. Reference numeral 25 denotes a gas purge valve, and reference numeral 26 denotes a gas tube, which is connected to a pressure source such as N ₂ or clean dry air. These are used when returning the vacuum chamber to atmospheric pressure.

The upper substrate 1b is held in close contact with the lower surface of the electrostatic attraction plate 28. Under the atmosphere, the upper substrate 1b is held by the electrostatic attraction plate 28 by suction. That is,
Reference numeral 41 denotes a suction / suction joint, and reference numeral 42 denotes a suction tube, which is connected to a vacuum source (not shown). The surface of the electrostatic suction plate 28 has a plurality of suction holes connected thereto.

When the surrounding area is the atmosphere, electrostatic suction may be used together, or when the electrostatic suction force is large, the suction suction may not be necessary.

The electrostatic attraction plate 28 is attached to a pressure plate 27 supported by a shaft 29, and the shaft 29 is fixed to housings 31, 32. The housing 31 is attached to the frame 2 by a linear guide 34, and the electrostatic attraction plate 28 has a structure capable of moving up and down. The vertical drive is performed by a motor 40 fixed to a bracket 38 on a frame 35 connected to the frame 2. The transmission of the drive is executed by the ball screw 36 and the nut housing 37. The nut housing 37 is connected to the housing 32 via a load meter 33, and operates integrally with the electrostatic suction plate 28 below the nut 32.

Therefore, the shaft 29 is driven by the motor 40.
Is lowered, the electrostatic attraction plate 28 holding the upper substrate 1b is lowered, and the upper substrate 1b is brought into close contact with the lower substrate 1a on the table 9 to apply a pressing force. In this case, the load meter 33 functions as a pressing force sensor, and by sequentially controlling the motor 40 based on a signal fed back, a desired pressing force can be applied to the upper and lower substrates 1a and 1b.

Since the lower substrate 1a is mounted in the direction of gravity, FIG.
As shown in the figure, it is sufficient to fix the positioning by pressing the positioning member 81 provided on the table 9 in the horizontal direction by the pressing roller 82, but at the time of the minute positioning immediately before bonding, the upper substrate 1b is placed on the lower substrate 1a. There is a possibility that the lower substrate 1a may shift or lift due to the contact with the sealing agent or the liquid crystal agent. Since there is a possibility that the lower substrate 1a may escape and fluctuate, the table 9 may be provided with a function of electrostatic attraction. If the table 9 is provided with pins that can move in the vertical Z-axis direction and is grounded, it is possible to easily prevent the cells from being charged after the substrates are bonded and to remove the cells from the table 9 easily.

In FIG. 2, reference numeral 60 denotes a position slightly below the electrostatic attraction plate 28 when the upper substrate 1b falls when the vacuum chamber is depressurized and the suction attraction force disappears and the upper substrate 1b falls. The receiving claw is received at the position, and is supported by the shaft 59 extending downward at two diagonal positions of the upper substrate 1b. More specifically, as shown in FIG. 3, the shaft 59 is vacuum-sealed through the housing 58 of the upper chamber 21 so that it can rotate and move up and down. That is, the shaft 59 is provided with a lifting actuator 62 fixed to a bracket 63 provided on the shaft 29.
As a result, not only can the shaft 29 be moved up and down independently of the up and down movement, but also the shaft 29 can be rotated by the rotary actuator 61.

Next, the electrostatic attraction plate 28 for attracting a substrate will be described.

The electrostatic attraction plate 28 is an insulating plate and has two rectangular concave portions. The flat electrode built in each concave portion is covered with a dielectric, and the main surface of the dielectric is electrostatic. It is flush with the lower surface of the suction plate 28. Each buried plate electrode is connected to a positive / negative DC power supply via an appropriate switch.

Therefore, when a positive or negative voltage is applied to each plate electrode, a negative or positive charge is induced on the main surface of the dielectric which is flush with the lower surface of the electrostatic attraction plate 28, and The upper substrate 1b is electrostatically attracted by a Coulomb force generated between the upper substrate 1b and the transparent electrode film due to the electric charge.
The voltage applied to each plate electrode may be the same polarity or different bipolar electrodes.

Next, a step of bonding substrates by the present substrate assembling apparatus will be described.

First, the jig holding the upper substrate 1b is mounted on the table 9, and the XYθ stage T1 is moved by the drive motor 5 to the substrate bonding section S2. Then, the pressure plate 27 and the electrostatic attraction plate 28 are lowered by the motor 40 via the shaft 29, and the upper substrate 1b on the table 9 is sucked and adsorbed. I do.

The XYθ stage T1 returns to the liquid crystal dropping unit S1 and the empty jig is removed, and the lower substrate 1 is placed on the table 9.
a is mounted and fixedly held at a desired position as shown in FIG.

Although not shown in FIG. 1, there is a dispenser for discharging the sealant on the frame 3, and the sealant is discharged while moving the lower substrate 1a in the X and Y directions by the motors 5 and 6 of the XYθ stage T1. Then, the sealant can be drawn on the lower substrate 1a in a closed (closed) pattern.
Thereafter, a liquid crystal agent is dropped from the dispenser 17 onto the lower substrate 1a. In this case, the sealing agent does not function as a dam, and the dropped liquid crystal agent does not flow away.

Next, the XYθ stage T1 is connected to the substrate bonding portion S
Then, the upper chamber 21 is lowered by the cylinder 22, and the flange portion 21a is brought into contact with the O-ring 44 to form the lower chamber 10 and the vacuum chamber. And
The vacuum valve 23 is opened to reduce the pressure inside the vacuum chamber. At this time, since the upper substrate 1b is in a state of being suction-adsorbed by the electrostatic attraction plate 28, as the decompression proceeds and the vacuum is applied, the suction-adsorbing force acting on the upper substrate 1b disappears,
The upper substrate 1b falls under its own weight. This is received by the receiving claw 60 as shown in FIG. 2 and is held at a position slightly below the electrostatic attraction plate 28 as shown in FIG.

When the inside of the vacuum chamber becomes sufficiently vacuum, a voltage is applied to the electrostatic attraction plate 28 to hold the upper substrate 1b on the receiving claw 60 on the electrostatic attraction plate 28 by Coulomb force. In this case, since the vacuum has already been established, no air remains between the electrostatic attraction plate 28 and the upper substrate 1b, and the upper substrate 1b does not dance when the air escapes. More importantly, the upper substrate 1b is in close contact with the electrostatic attraction plate 28 without air. Therefore, no discharge is generated by the induced charge.

When a discharge is generated while leaving air, the air expands, and the upper substrate 1b may be peeled off from the electrostatic attraction plate 28 or the upper substrate 1b made of thin glass may be destroyed. Since no air is present, such abnormal accidents do not occur.

After that, the shaft 59 is lowered by the lifting actuator 62, and then the shaft 59 is rotated by the rotating actuator 61 so that the receiving claw 60 does not hinder the bonding of the upper and lower substrates. The pressure plate 27 is lowered at 40 and the motor 40 is controlled while measuring the pressing force with the load meter 33 to bond the upper and lower substrates 1a and 1b at a desired interval.

In this case, since the upper substrate 1b is in close contact with the electrostatic attraction plate 28 and its central portion does not hang down, it adversely affects the spacers in the liquid crystal agent and makes it impossible to align the substrates. Never be. Incidentally, the alignment is performed by reading the alignment marks provided on the upper and lower substrates 1a and 1b with an image recognition camera from a viewing window provided in the upper chamber 21 (not shown), and measuring the position by image processing, and the XYθ stage T1 Each of the stages 4a to 4c is slightly moved to perform high-accuracy positioning.

When the bonding is completed, the vacuum valve 23
, The gas purge valve 25 is opened, and N ₂ or clean dry air is supplied into the vacuum chamber. After returning to the atmospheric pressure, the gas purge valve 25 is closed, the upper chamber 21 is raised by the cylinder 22, and the XYθ stage T1 is Returning to the liquid crystal dropping section S1, the cell is removed from the table 9 and the next lamination is prepared. Here, since the cell after bonding may be charged, it is preferable to remove the cell from the table 9 after performing a charge removal treatment such as contacting with a grounded charge removal bar or blowing ion wind. The sealing agent is hardened in the cell removed from the table 9 by a UV light irradiation device or a heating device on the downstream side.

In the above embodiment, since the sealing agent is discharged, the liquid crystal is dropped, and the process immediately proceeds to bonding, the production yield can be improved since the substrate is less likely to receive dust. Also, XY
The θ stage T1 can be used to transfer the upper substrate 1b into the vacuum chamber, and the size of the apparatus is reduced.

The present invention is not limited to the embodiment described above.
You may implement as follows.

(1) For supplying the upper substrate 1b to the electrostatic attraction plate 28, a plurality of receiving claws (equivalent to the receiving claws 60 in FIG. 2) which can expand and contract in the vertical direction are provided on the XYθ stage T1. Here, when the XYθ stage T1 is at the liquid crystal dropping portion S1, the upper substrate 1b may be placed on the plurality of receiving claws, and the XYθ stage T1 may be moved to the substrate bonding portion S2.

(2) Further, the suction may be directly performed on the electrostatic suction plate 28 by the robot hand.

(3) The receiving claw provided on the XYθ stage T1 described in (1) above may receive the upper substrate 1b which falls as the pressure reduction proceeds.

(4) Further, the receiving claw 60 shown in FIG. 2 or the receiving claw provided on the XYθ stage T1 described in the above (1) is used to hold the upper substrate 1b before the upper substrate 1b falls. Alternatively, the pressure may be switched to the electrostatic attraction by advancing the pressure reduction from the state of being attracted and attracted to the electrostatic attraction plate 28 after being pressed against the electrostatic attraction plate 28. In this case, by preventing the upper substrate 1b from being physically in close contact with the electrostatic attraction plate 28,
The air between the upper substrate 1b and the electrostatic attraction plate 28 can be evacuated and reduced in pressure.

(5) Further, the upper substrate 1b is slightly separated from the electrostatic attraction plate 28 by the receiving claw 60 of FIG. 2 or the receiving claw provided on the XYθ stage T1 described in the above (1). And the electrostatic attraction may be performed during the decompression without suction and attraction.

(6) In FIG. 2, two corners (two corners forming a diagonal) of the upper substrate 1b are held by the receiving claws 60, but four corners of the upper substrate 1b are held. (Four corners) may be held, or four sides, two sides in the longitudinal direction, or two sides in the width direction of the upper substrate 1b may be held by appropriate means.

[0048]

As described above, according to the present invention, even if the size of the substrate is increased and the thickness of the substrate is reduced, it is possible to bond substrates of the same degree with high precision in a vacuum.

[Brief description of the drawings]

FIG. 1 is a schematic view of a substrate assembling apparatus showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a situation when upper and lower substrates are bonded together.

FIG. 3 is a cross-sectional view of a main part showing a state immediately before the upper and lower substrates are bonded by applying an electrostatic attraction force to an upper substrate.

[Explanation of symbols]

 S2 Substrate bonding portion 1a Lower substrate 1b Upper substrate 9 Table 10 Lower chamber 21 Upper chamber 23 Vacuum valve 27 Pressing plate 28 Electrostatic suction plate 59 Shaft 61 Rotating actuator 62 Elevating actuator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Saito 5-2-2 Koyodai, Ryugasaki-shi, Ibaraki Pref. Hitachi Techno Engineering Co., Ltd. (72) Inventor Yukihiro Kawasumi 5-2-2 Koyodai, Ryugasaki-shi, Ibaraki (72) Inventor Haruo Mika 5-5-2 Koyodai, Ryugasaki-shi, Ibaraki Pref. Hitachi-Techno Engineering Co., Ltd. (72) Inventor Akira Hirai 5 Koyodai, Ryugasaki-shi, Ibaraki F-term (reference) No. 2 in Hitachi R & D Co., Ltd. Development Laboratory 2H088 FA01 FA10 FA16 FA30 HA01 2H089 NA49 NA60 QA11 2H090 JC12 LA02 5C094 AA14 AA42 AA43 AA55 BA43 GB01

Claims (5)

[Claims] 1. A substrate to be bonded is held on the lower surface of a pressure plate, the other substrate to be bonded is held on a table and opposed to each other, and the gap is reduced in vacuum by an adhesive provided on any one of the substrates. What is claimed is: 1. A method for assembling substrates to be bonded, comprising: applying an electrostatic attraction force from a pressing plate to one of the substrates to hold one substrate on the pressing plate; 2. The substrate to be bonded is held on the lower surface of a pressure plate, the other substrate to be bonded is held on a table and opposed to each other, and the gap is reduced in vacuum by an adhesive provided on one of the substrates. In the method of assembling the substrates to be bonded, one substrate is held on the pressure plate by suction attraction in the air, and the suction attraction disappears in the process of decompression, and the other substrate that falls is slightly separated from the pressure plate. And applying the electrostatic attraction force to the one substrate from the pressing plate to hold the one substrate on the pressing plate for bonding. 3. The substrate to be bonded is held on the lower surface of the pressure plate, the other substrate to be bonded is held on a table and opposed to each other, and the gap is reduced in vacuum by an adhesive provided on one of the substrates. In the method of assembling the substrates to be bonded, one of the substrates is held against the pressure plate by suction attraction in the atmosphere and pressed against the other, and before and after the suction attraction disappears in the process of decompression, the pressure is applied to this one substrate from the pressure plate. A method of assembling a substrate, wherein one of the substrates is continuously held on a pressure plate by applying an electrostatic attraction force to perform bonding. 4. A substrate to be bonded is held on the lower surface of a pressure plate located above in a vacuum chamber, and the other substrate to be bonded is held on a table located below in a vacuum chamber to hold both substrates. In a substrate assembling apparatus in which the distance between both substrates is reduced in a vacuum with an adhesive provided on one of the substrates and the substrates are attached to each other, a means for holding one of the substrates with a suction force by a pressure plate and an electrostatic device Providing means for holding by suction force, means for receiving one substrate that falls when suction suction force disappears in the process of decompression in the vacuum chamber at a position slightly away from the pressure plate or one of the pressure plates A means for pressing the substrate is provided, and when one of the substrates is on the receiving means or the pressing means, at least an electrostatic attraction force is applied to hold the one substrate on the pressing plate. A substrate assembling apparatus, characterized in that the substrate assembling means is provided. 5. A substrate to be bonded is held on the lower surface of a pressure plate located above in a vacuum chamber, and the other substrate to be bonded is held on a table located below in a vacuum chamber to hold both substrates together. In a substrate assembling apparatus in which two substrates are attached to each other in a vacuum by using an adhesive provided on one of the substrates to reduce the distance between the two substrates in a vacuum, the table can be moved horizontally between inside and outside of a vacuum chamber. A means for drawing an adhesive on the other substrate on the table located outside the chamber in a closed pattern; and a means for dropping liquid crystal in the closed pattern of the adhesive on the other substrate on the table. The pressure plate is provided with means for holding one substrate with suction and suction force and means for holding it with electrostatic suction force. Means for receiving one of the substrates to be lowered at a position slightly away from the pressure plate or means for pressing one of the substrates against the pressure plate are provided. A substrate assembling apparatus, comprising: means for holding one substrate on a pressing plate by applying an attraction force.