JP4585206B2 - Substrate bonding method and bonding apparatus - Google Patents

Description

  The present invention relates to a method for bonding substrates and a bonding apparatus for bonding two substrates such as a liquid crystal display panel.

  As is well known, in manufacturing a liquid crystal display panel, two transparent substrates are bonded together with a sealant, and a substrate is assembled by interposing a liquid crystal, which is a liquid material, between the substrates.

  Conventionally, in order to assemble two substrates, a step of applying a sealing agent made of a viscoelastic material to one substrate in a rectangular frame shape, a step of dropping a predetermined amount of liquid crystal on one or the other substrate, and the above 2 And a step of laminating a single substrate with the sealing agent under a reduced pressure atmosphere.

  In order to secure the interval between the two substrates to be bonded together in the order of μm, a spacer is provided at the interval. Examples of the spacer include a ball spacer that spreads a spherical resin having a particle diameter of several μm on the inner surface (surface to be bonded) of one substrate, and a photo spacer that has a protrusion having a height of several μm on the inner surface of one substrate. Are known.

  When two substrates are bonded together, first, the two substrates are imaged at a predetermined interval, and the substrates are roughly aligned based on the imaging result. Next, the two substrates are bonded together with the above-mentioned sealant, and two more substrates are imaged in that state, and one substrate is moved by a predetermined amount in a predetermined direction based on the imaging result, thereby the two substrates. The precise alignment is performed. In this case, the amount of movement of the substrate is equal to the amount of deviation obtained from the imaging result.

  In the case of precisely aligning two bonded substrates, when one substrate is moved, the spacer is interlocked with the movement of the substrate. When the spacer is a ball spacer, it rolls by the movement of the substrate, so that the frictional resistance acting between the substrates can be relatively small. However, when the spacer is a photo spacer, the frictional resistance increases because the spacer is in sliding contact with the substrate in a surface contact state.

  If the frictional resistance between the substrates is large, when the substrate on the moving side is moved by a predetermined amount, the frictional resistance acting on the substrate to be moved may be larger than the holding force that holds the substrate. In that case, even if the substrate holding means is moved by a movement amount equal to the displacement amount based on the imaging result, the actual movement amount of the substrate is smaller than the displacement amount, so that the two substrates are aligned with high accuracy. I can't.

  For this reason, in order to accurately align the two substrates within the allowable accuracy, the alignment operation described above must be performed many times, which may lead to a decrease in productivity.

  Moreover, if the amount of positional displacement between the two substrates based on the imaging result is small, even if the substrate is moved according to the small amount of positional displacement, the substrate is actually corrected in the direction in which the displacement is corrected by the frictional resistance. In such a case, it may be difficult to perform precise alignment because it may not move.

  It is an object of the present invention to provide a substrate bonding method and a bonding apparatus capable of quickly and precisely aligning two bonded substrates.

The present invention includes a step of contacting two substrates through a sealant or a liquid substance,
Determining the amount of positional deviation between the two substrates in contact;
Comprising a step of correcting the positional deviation of these two substrates by moving at least one of the two substrates in the correction movement amount obtained by multiplying the compensation coefficient to the positional deviation amount,
When correcting the positional deviation of the two substrates in contact with each other a plurality of times, the correction coefficient is K, the correction movement amount of the previous substrate is M, the previous deviation amount of the two substrates is δn, and at least one of them is corrected. If the current shift amount after the substrate is moved by the correction movement amount M is δm,
The correction coefficient K is K = M / (δn−δm) .

This invention is a bonding method in which a sealing agent for sealing a liquid substance is applied to either one of two substrates, and the two substrates are bonded together with the sealing agent,
A step of holding one substrate and the other substrate apart in the vertical direction;
Imaging two held substrates and determining the amount of positional deviation between the two substrates based on the imaging results;
Aligning the two substrates based on the amount of misalignment and then contacting the substrates via the sealant or liquid material;
Imaging the two substrates in contact and determining the amount of positional deviation between the two substrates;
Correction moving amount obtained by multiplying the compensation coefficient to the displacement amount of the contacted two substrates by moving at least one of said two substrates comprises a step of correcting the positional deviation of the substrate,
When correcting the positional deviation of the two substrates in contact with each other a plurality of times, the correction coefficient is K, the correction movement amount of the previous substrate is M, the previous deviation amount of the two substrates is δn, and at least one of them is corrected. If the current shift amount after the substrate is moved by the correction movement amount M is δm,
The correction coefficient K is K = M / (δn−δm) .

This invention is a bonding apparatus for applying a sealing agent for sealing a liquid substance to either one of two substrates, and bonding the two substrates with the sealing agent,
A holding device for holding one substrate and the other substrate apart from each other in the vertical direction, and driving the substrates relatively in the X, Y, Z, and θ directions to bond the two substrates;
An imaging device for imaging two substrates held by the holding device;
Then the positional displacement amounts of the two substrates on the basis of the imaging result of the imaging device, these substrates by moving at least one of the two substrates in the correction movement amount obtained by multiplying the compensation coefficient to the positional deviation amount Comprising a control device for correcting the positional deviation of
The control apparatus sets the correction coefficient to K, the correction movement amount of the previous substrate to M, the previous shift amount of the two substrates to δn, and the current movement after moving at least one of the substrates by the correction movement amount M. If the amount of deviation is δm,
In the substrate bonding apparatus, the correction coefficient K is calculated based on an equation of K = M / (δn−δm) .

  According to the present invention, one of the two substrates that are in contact with each other via the sealant or the liquid substance is moved by a correction movement amount obtained by multiplying the deviation amount from the other substrate by the correction coefficient. Therefore, even if a deviation occurs between one of the substrates and the holding device due to the frictional resistance between the other substrate, the amount of the deviation is compensated, so that the alignment of the two substrates can be performed quickly and precisely. Can be performed.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 to FIG. 6 show an embodiment of the present invention, and FIG. 1 is an explanatory view showing a schematic configuration of a liquid crystal display panel assembling apparatus 1. The assembling apparatus 1 includes a sealing agent application apparatus 2. The coating device 2 is supplied with a first substrate 3 which is one of the first and second substrates 3 and 4 constituting the liquid crystal display panel P shown in FIG.

  The coating apparatus 2 includes a table on which the first substrate 3 is supplied and placed, and a coating nozzle (both not shown) arranged above the table, and the coating nozzle is attached to the first substrate 3. By relatively driving in the X, Y, and Z directions, a sealing agent 5 (shown in FIG. 6) made of a viscoelastic material is applied to the inner surface of the first substrate 3 in a rectangular frame shape. .

  The first substrate 3 coated with the sealing agent 5 is supplied to the dropping device 7. The dropping device 7 has a table on which the first substrate 3 is placed and a dropping nozzle (both not shown) disposed above the table, and the dropping nozzle is disposed on the first substrate 3. Driven relatively in X, Y and Z directions. As a result, liquid droplets in the form of a liquid substance are dropped and supplied in a predetermined arrangement pattern, for example, in a matrix form, in a region surrounded by the sealing agent 5 on the inner surface of the first substrate 3.

  The first substrate 3 onto which the liquid crystal has been dropped is supplied to the bonding apparatus 11. The bonding apparatus 11 is supplied with the second substrate 4 together with the first substrate 3. Then, the first substrate 3 and the second substrate 4 are positioned and bonded as will be described later. Thereby, as shown in FIG. 6, the liquid crystal display panel P in which the liquid crystal 8 is filled between the pair of substrates 3 and 4 is assembled.

  The bonding apparatus 11 has a chamber 12 as shown in FIG. The inside of the chamber 12 is depressurized by a decompression pump 10 to a predetermined pressure, for example, about 1 Pa. A loading / unloading port 14 opened and closed by a shutter 13 is formed on one side of the chamber 12, and the first substrate 3 and the second substrate 4 are loaded / unloaded from the loading / unloading port 14.

  A first holding table 15 is provided in the chamber 12. The first holding table 15 is driven in the X, Y, and θ directions by the first drive source 16, and the sealant 5 is applied to the holding surface 15a (upper surface) and the liquid crystal 8 is applied. The first substrate 3 onto which the liquid crystal 8 has been dropped is supplied with the inner surface (the surface to be bonded) onto which the liquid crystal 8 has been dropped facing upward. As for the 1st board | substrate 3 supplied to the holding surface 15a, the outer surface (lower surface) is hold | maintained by the said holding surface 15a by predetermined | prescribed holding force by vacuum suction etc., for example.

  Above the first holding table 15, a second holding table 18 that is driven in the Z direction by the second driving source 17 to come in contact with and separate from the first holding table 15 is disposed. The second substrate 4 is held by the electrostatic force with the outer surface (upper surface) in contact with the holding surface 18a on the lower surface of the second holding table 18. The first holding table 15 and the second holding table 18 constitute a holding device.

  As will be described later, when the pressure inside the chamber 12 is reduced by the decompression pump 10, the holding force of the first substrate 3 by vacuum suction becomes smaller than the holding force of the second substrate 4 by static electricity. A spacer S is formed on the inner surface (lower surface) of the second substrate 4 as shown in FIG.

  The first substrate 3 held on the holding surface 15a of the first holding table 15 and the second substrate 4 held on the holding surface 18a of the second holding table 18 have four corners of the chamber 12 respectively. Images are picked up by four sets of imaging devices 21 (only two sets are shown) arranged below. Each imaging device 21 includes a first imaging camera 22 and a second imaging camera 23 having an imaging magnification higher than that of the first imaging camera 22.

  The first and second imaging cameras 22 and 23 of each imaging device 21 are driven in the X, Y, and Z directions by a positioning device 24 having X, Y, and Z tables. 24 is installed on a mounting plate 25 disposed below the chamber 12.

  At least a portion of the bottom wall of the chamber 12 facing the positioning devices 24 is formed in a transparent window 26. A portion corresponding to the transparent window 26 of the first holding table 15 disposed in the chamber 12 is formed in the cavity 27. The hollow portion 27 is formed on the four corners of the first substrate 3 held on the holding surface 15 a of the first holding table 15 and on the holding surface 18 a of the second holding table 18 via the first substrate 3. The four corners of the held second substrate 4 can be imaged by the first and second imaging cameras 22 and 23.

  Although not shown, coarse alignment marks and fine alignment marks are provided on the four corners of the first substrate 3 and the second substrate 4 outside the sealant 5, respectively. By matching the coarse alignment marks of each substrate 3, 4, the first substrate 3 and the second substrate 4 can be coarsely aligned, and by matching the fine alignment marks of each substrate, The pair of substrates 3 and 4 can be precisely aligned.

  In addition, in order to image the 1st, 2nd board | substrates 3 and 4, although the cavity part 27 was formed in the 1st holding table 15, the 1st holding table 15 whole is formed without forming the cavity part 27. May be formed of a light-transmitting material.

  As shown in FIG. 3, the imaging signals of the four sets of the first imaging camera 22 and the second imaging camera 23 (only one set is shown in FIG. 3) are input to the image processing unit 31 and converted into coordinate signals. The The coordinate signal converted by the image processing unit 31 is input to an arithmetic processing unit 33 provided in the control device 32. In the arithmetic processing unit 33, a pair of coarse alignment marks or precise positions at the four corners of the first and second substrates 3 and 4 captured by the four sets of the first imaging camera 22 and the second imaging camera 23. From the coordinates of the alignment marks, the relative displacement amounts of the substrates 3 and 4 in the X, Y and θ directions are calculated.

  When the amount of positional deviation between the pair of substrates 3 and 4 is calculated by the arithmetic processing unit 33, the amount of positional deviation is stored in the storage unit 34 and also output to the driving unit 35. Accordingly, the drive unit 35 outputs a drive signal to the first drive source 16 that drives the first holding table 15, and drives the first holding table 15 in the X direction, the Y direction, and the θ direction. The first substrate 3 and the second substrate 4 are aligned.

  The alignment between the first substrate 3 and the second substrate 4 is a rough alignment based on the imaging signal from the first imaging camera 22 and a precise alignment based on the imaging signal from the second imaging camera 23. Is done by.

  The coarse alignment is performed in a state where the second substrate 4 is separated from the first substrate 3 at a predetermined interval, and the fine alignment is performed on the first substrate 3 by the second substrate 4 by the sealant 5. Performed in contact. When precise alignment is performed, a spacer S protrudes from the inner surface of the second substrate 4.

  Therefore, the frictional resistance between the spacer S and the first substrate 3 becomes larger than the holding force of the first and second substrates 3 and 4, and the substrates 3 and 4 may be displaced. In this embodiment, since the first substrate 3 is vacuum-sucked to the holding surface 15a of the first holding table 15, when the pressure in the chamber 12 is reduced, the holding force of the first substrate 3 decreases. . Thereby, the first substrate 3 may be displaced on the holding surface 15a of the first holding table 15 due to the frictional resistance.

  Therefore, if the amount of positional deviation between the first substrate 3 and the second substrate 4 is obtained from the image pickup signal of the second image pickup camera 23, the correction for moving the first substrate 3 by the first holding table 15 is performed. Positioning is performed by setting the amount of movement to a value obtained by multiplying the amount of positional deviation by a correction coefficient K larger than 1, and positioning is performed in accordance with the displacement of the first substrate 3 with respect to the first holding table 15 due to frictional resistance. The loss of accuracy is compensated.

For example, when the amount of positional deviation between the first substrate 3 and the second substrate 4 obtained by the second imaging camera 23 is δn (μm), the first holding table 15 is moved based on the amount of positional deviation δn. After aligning the correction movement amount as M (μm), when the positional deviation amount is measured again by the second imaging camera 23, when the positional deviation amount is δm (μm), the correction coefficient K is
K = f (S) ... It is set as the equation (1). Note that S = M / (δn−δm).

  That is, the arithmetic processing unit 33 calculates a value obtained by multiplying the amount of positional deviation of the first and second substrates 3 and 4 obtained from the imaging signal of the second imaging camera 23 by the correction coefficient K. Based on the result, a drive signal is output from the drive unit 35 to the first drive source 16.

  When the precise alignment is performed a plurality of times, the positional deviation amounts of the pair of substrates 3 and 4 imaged by the second imaging camera 23 and calculated by the arithmetic processing unit 33 are stored in the storage unit 34.

Therefore, every time precise alignment is performed, the correction coefficient K based on the above equation (1) can be calculated using the previous positional deviation amount δn stored in the storage unit 34.
The drive unit 35 of the control device 32 also outputs a drive signal to the second drive source 17 and the positioning device 24.

  Next, a process of bonding the first substrate 3 and the second substrate 4 by the bonding apparatus 11 having the above configuration will be described with reference to the flowcharts of FIGS. 4 and 5.

  First, in S <b> 1, the first substrate 3 is supplied into the chamber 12 of the bonding apparatus 11 by a robot (not shown) and sucked and held on the holding surface 15 a of the first holding table 15. In S <b> 2, the second substrate 4 is supplied into the chamber 12 and is sucked and held on the holding surface 18 a of the second holding table 18. When the second holding table 18 holds the second substrate 4, the second holding table 18 is lowered to a predetermined height, and then the pressure reducing pump 10 is operated to reduce the pressure in the chamber 12. The shutter 13 is closed before the decompression pump 10 is operated.

  When the inside of the chamber 12 is depressurized to a predetermined pressure, the rough alignment marks provided at the four corners of the first substrate 3 and the second substrate 4 are imaged by the first imaging camera 22 in S3. The imaging signal of the first imaging camera 22 is converted into a digital signal by the image processing unit 31 and then input to the arithmetic processing unit 33. Thereby, the amount of positional deviation between the first substrate 3 and the second substrate 4 is calculated.

  In S4, a drive signal is output from the drive unit 35 to the first drive source 16 based on the amount of displacement calculated by the arithmetic processing unit 33, and the first holding table 15 is driven in the θ, X, and Y directions. Is done. Thereby, the first substrate 3 is roughly positioned with respect to the second substrate 4.

  In S <b> 5, following the rough positioning in S <b> 4, the second holding table 18 is driven in the descending direction (proximity direction), and the second substrate 4 is placed on the first substrate 3 held on the first holding table 15. Contact is made through the sealant 5. In S6, the fine alignment marks at the four corners of the first and second substrates 3 and 4 brought into contact with each other through the sealant 5 are imaged by the second imaging camera 23 with a high magnification. At this time, the second imaging camera 23 is positioned by the positioning device 24 at a position where the fine alignment mark can be imaged.

  In the control device 32, the positional deviation amount between the first substrate 3 and the second substrate 4 is obtained from the imaging signal of the second imaging camera 23, and the positional deviation amount obtained by the second imaging camera 23 in S7. The first substrate 3 is driven in a direction in which the positional deviation is eliminated with a correction movement amount according to the above. At that time, since the spacer S formed on the second substrate 4 is in sliding contact with the first substrate 3, the first substrate 3 having a lower holding force than the second substrate 4 due to the frictional force is the first substrate 3. The holding table 15 may be displaced on the holding surface 15 a in the direction opposite to the moving direction of the first holding table 15.

  Therefore, in S8, if the first precise positional deviation correction is performed, the second imaging camera 23 again captures the precise alignment marks on the first and second substrates 3 and 4, and these substrates 3 and 3 are imaged. 4 is measured.

  When the positional deviation amount is measured from the imaging signal obtained by the second imaging camera 23 in S8, a correction coefficient K is obtained based on the positional deviation amount in S9, and a new correction movement is performed based on the correction coefficient K. A quantity M is calculated.

For example, the positional deviation amount before correction (previous deviation amount) δn is 5 μm, the initial correction movement amount M is set to 5 μm, and the positional deviation amount of the first substrate 3 is corrected. If the amount of misalignment δm is 4 μm, the correction coefficient K is
K = 5 / (5-4) = 5
It becomes. Therefore, the next (second) correction movement amount M is a value obtained by multiplying the positional deviation amount measured after the first correction by the correction coefficient K.
M = 4 × 5 = 20 (μm)
It becomes.

  In S10, the second correction movement is performed. In the second correction movement, the first substrate 3 is moved based on the correction movement amount M calculated in S9. That is, at the time of the second precise alignment, the positional displacement amount between the first substrate 3 and the second substrate 4 is 4 μm, whereas the correction movement amount is 20 μm.

  Also at the time of the second precise alignment, the first substrate 3 is displaced on the first holding surface 15a by the frictional resistance with the spacer S formed on the second substrate 4. However, the correction movement amount M of the first substrate 3 is set to a value that compensates for the displacement amount that the first substrate 3 is displaced on the first holding surface 15a during the precise alignment. The substrate 3 can be positioned with high accuracy with respect to the second substrate 4.

  Theoretically, if the first substrate 3 is corrected and moved by the correction movement amount M obtained in S9, the first and second substrates 3 and 4 can be aligned with high accuracy. However, the alignment accuracy with respect to the second substrate 4 may not be sufficiently obtained only by performing the correction of the first substrate 3 twice under various conditions.

  Therefore, in S11, after the second alignment, the second imaging camera 23 captures the precise alignment marks on the first and second substrates 3 and 4 again, and positions them between these substrates 3 and 4. Measure whether there is a gap.

  If there is a positional deviation, the positional deviation amount δn at the time of the previous measurement (second measurement) stored in the storage unit 34 of the control device 32 in S12 and the positional deviation due to the current measurement (third time). The correction coefficient K is obtained again from the amount δm and the previous correction movement amount M, and the first substrate 3 is moved by the correction movement amount M1 obtained by multiplying the correction coefficient K by the positional deviation amount δm measured for the third time. Perform alignment.

For example, if the third positional deviation amount δm is 1 μm, the previous positional deviation amount δn is 4 μm and the previous corrected movement amount M is 20 μm.
K = 20 / (4-1) ≈6.67
It becomes. Therefore, the third correction movement amount M is
M = 1 × 6.67≈6.67 (μm)
It becomes.

  In S13, the first substrate 3 is moved based on the corrected movement amount M calculated in S12. Thereby, the first substrate 3 and the second substrate 4 can be precisely aligned.

  Moreover, in the third precise alignment, the amount of positional deviation to be adjusted is 1 μm, which is smaller than the amount of positional deviation of the second time 4 μm. However, since the correction movement amount M of the first holding table 15 at this time is about 6.67 times the displacement amount of 1 μm, even if the displacement amount of the first substrate 3 is small, One substrate 3 can be reliably moved in a predetermined direction.

  When it is desired to align the first substrate 3 and the second substrate 4 with higher accuracy, the above-described process may be repeated a plurality of times. Usually, the precise alignment is repeated twice. By doing so, it is possible to align with high accuracy. However, if it is performed three times, higher alignment accuracy can be obtained with higher accuracy.

  That is, since the positional deviation amount calculated by the arithmetic processing unit 33 is stored in the storage unit 34 of the control device 32, the correction coefficient K is calculated using the previous positional deviation amount δn stored in the storage unit 34. It is possible to calculate.

  Note that, even if the fine alignment is performed twice or more, whether or not there is a positional shift between the first substrate 3 and the second substrate 4 after the final fine alignment is performed is determined in the second imaging. A step of confirming with the camera 23 may be provided.

  The first substrate 3 and the second substrate 4 are in contact with each other via a sealant 5 made of a viscoelastic agent. For this reason, even if the first substrate 3 is shifted by a predetermined amount and positioned, the first substrate 3 may return in the direction opposite to the moving direction due to the restoring force of the sealant 5, which may cause a shift.

  For this reason, when there is a possibility that the return due to the elasticity of the sealing agent 5 may occur, the correction movement amount at the time of precise positioning is set to a value that compensates for the deviation amount caused by the return of the sealing agent 5. For example, when the correction coefficient is obtained by the above equation (1), if the current shift amount δm is set to a value obtained by adding the return amount due to the elasticity of the sealant 5, the first substrate 3 is sealed after the alignment. By returning with the elasticity of 5, the first substrate 3 and the second substrate 4 can be precisely aligned.

  When precise alignment is performed, the first substrate 3 may be displaced on the holding surface 15a of the first holding table 15 in the direction opposite to the moving direction of the first holding table 15 as described above. When the first substrate 3 is displaced, it is conceivable that the fine alignment mark formed on the first substrate 3 is out of the field of view of the second imaging camera 23.

  Therefore, when the first substrate 3 and the second substrate 4 are precisely aligned, the second imaging camera 23 is moved in the X and Y directions while moving the first holding table 15 by the predetermined correction movement amount M. The second imaging camera 23 is moved by the positioning device 24 supported so as to be movable in the Z direction so that the fine alignment mark of the second substrate 4 held on the holding table 18 is positioned at the center of the visual field. In this way, after the movement of the holding table 15 with the correction movement amount M is completed, at least imaging is performed around the fine alignment mark on the second substrate 4 within the visual field region of the second imaging camera 23. An area having a size half the visual field range of the camera 23 exists. Moreover, after the holding table 15 has completed the movement of the correction movement amount M, the relative distance between the precision alignment marks on the two substrates 3 and 4 is larger than that before the movement of the holding table 15 with the correction movement amount M. Therefore, the precision alignment marks of the two substrates 3 and 4 that were originally located within the field of view of the second imaging camera 23 deviate from the field of view after moving by the correction movement amount M. This can be prevented as much as possible.

  In the above embodiment, the correction coefficient for setting the correction movement amount of the first substrate is the same as the correction movement amount of the previous substrate, the previous positional deviation amount of the two substrates, and the previous correction movement amount. It is determined by the amount of positional deviation between the two substrates this time after moving one substrate.

  However, in the case where two substrates are bonded together under the same conditions, if the correction coefficient is set first, then the correction movement amount is determined by the same correction coefficient, and the alignment is performed. Also good. In other words, the correction coefficient may not be calculated each time as in the above embodiment, but may be a preset setting value. Whether the correction coefficient is calculated each time or the setting value is used depends on the quality of the substrate and the lot. It may be determined according to. For example, in the case of a substrate with a large variation in substrate thickness, the magnitude of the frictional force acting between the substrates may change each time due to the variation in substrate thickness, so the correction coefficient is calculated each time. On the other hand, in the case of a substrate of a type with little variation in substrate thickness, the magnitude of the frictional force acting between the substrates is considered to be almost constant contrary to the above, and the correction coefficient may be set as a set value. Therefore, these can be switched and used according to the type and lot of the substrate.

  As described above, according to the first embodiment of the present invention, one of the two substrates that are in contact with each other via the sealant or the liquid substance is moved in a correction amount that is larger than the amount of deviation from the other substrate. It was made to move with.

  Therefore, even if a deviation occurs between one of the substrates and the holding means due to the frictional resistance between the other substrate, the amount of the deviation is compensated, so that the alignment of the two substrates can be performed quickly and precisely. Can be performed.

  In the above embodiment, the obtained correction coefficient K is an example of multiplying the amount of positional deviation between the first and second substrates 3 and 4 as they are, but instead, the correction coefficient K has a lower limit value and an upper limit value, or When either one is set and the obtained correction coefficient K is smaller than the lower limit value or larger than the upper limit value, the correction coefficient K may be the lower limit value or the upper limit value.

  For example, when the lower limit value of the correction coefficient K is “3” and the upper limit value is “8”, if the calculated correction coefficient is K = 5, the correction coefficient K is between the upper limit value and the lower limit value. , K = 5 is used as it is. If the obtained correction coefficient is K = 2, K = 3 because the correction coefficient K is smaller than the lower limit value. If the obtained correction coefficient is K = 10, K = 8 since the correction coefficient K is larger than the upper limit value.

  By doing so, the correction coefficient K is too small, and the amount of displacement that the first substrate 3 moves on the holding surface 15a of the first holding stage 15 cannot be compensated at the time of precise alignment, or the correction is made on the contrary. The coefficient K is too large, and the first substrate 3 is moved with respect to the second substrate 4 more than the amount of deviation between the first substrate 3 and the holding surface 15a, and the first and second substrates are moved. It is possible to prevent the possibility of increasing the amount of misalignment between 3 and 4.

  Either a preset correction coefficient or a correction coefficient calculated using the above equation (1) can be selected in accordance with the magnitude of the positional deviation between the first and second substrates 3 and 4. .

  For example, if a threshold value is set and the amount of positional deviation is larger than the threshold value, a correction coefficient preset in the storage unit 34 is used, and the amount of positional deviation is less than the threshold value. If there is, the correction coefficient is calculated using the above formula (1).

  That is, as the correction movement amount of the first substrate 3 with respect to the second substrate 4 increases, the rate of increase in the amount of misalignment between the first substrate 3 and the holding surface 15a of the first holding table 15 decreases. It has been confirmed by experiment that there is a case of doing so.

  In such a case, for example, when the first substrate 3 is moved with a correction movement amount of 5 μm with respect to the second substrate 4, there is a positional deviation of 4 μm between the first substrate 3 and the holding surface 15 a. As a result, the first substrate 3 moves only about 1 μm relative to the second substrate 4. However, when the first substrate 3 is moved with a correction movement amount of 30 μm with respect to the second substrate 4, the positional deviation amount between the first substrate 3 and the holding surface 15 a is about 5 μm, One substrate 3 moves about 25 μm relative to the second substrate 4.

  Therefore, when the amount of misalignment between the first and second substrates 3 and 4 is about 30 μm, the correction coefficient K obtained using the above equation (1) is “3” or “4”. When the first substrate 3 is moved with respect to the second substrate 4 with the correction movement amount calculated using the correction coefficient K, the first substrate 3 is moved more than necessary with respect to the second substrate 4. Can cause consequences.

  Therefore, a threshold value (for example, 20 μm) is set for the positional deviation amount between the first and second substrates 3 and 4, and if the positional deviation amount exceeds the threshold value, the storage unit 34 is preliminarily stored. A correction movement amount is calculated using the set correction coefficient K (for example, K = 1.2).

  By doing in this way, even in the above-described case, it is possible to prevent the problem of moving the first substrate 3 with respect to the second substrate 4 more than necessary and to perform alignment quickly.

It should be noted that the amount of misalignment between the first and second substrates 3 and 4 is compared, the amount of misalignment is compared with a threshold value, the selection is made based on the comparison result, that is, the set correction coefficient is used. The selection of whether to use the correction coefficient according to the equation can be performed by the arithmetic processing unit 33 of the control device 32.

  Another example of how to obtain the correction coefficient K is the following method. That is, this is a method for obtaining the correction coefficient K based on a plurality of past data. The data may include a correction coefficient, a positional deviation between the first and second substrates 3 and 4, a correction movement amount for aligning the first substrate 3 with the second substrate 4, and the like.

  For example, when using data for the past five times, the same procedure as in the above-described embodiment is used until the number of alignments between the first and second substrates 3 and 4 is six, that is, the first time uses a correction coefficient. Do the alignment without. In the seventh and subsequent positioning, a new correction coefficient is obtained in the same manner as in the above embodiment every time the positional deviation between the first and second substrates 3 and 4 is measured. Then, the average value of the correction coefficients is calculated using the correction coefficients for the past five times before this time, and the correction movement amount is calculated using the calculated average value of the correction coefficients.

  In the first embodiment, the correction coefficient K has been described as an example using a numerical value larger than 1. However, a numerical value smaller than 1 may be used.

  That is, when the substrate is held on the holding table via the elastic member, the horizontal direction in which the elastic member is in the alignment direction due to the contact resistance between the substrate and the sealing agent or liquid crystal when the two substrates are aligned. May be elastically deformed. Then, a restoring force is generated in the deformed elastic member, and this restoring force acts during the alignment of both substrates.

  Therefore, when the alignment is repeated a plurality of times, the deformation of the elastic member is accumulated, and the correction movement amount between the two substrates becomes small, until one alignment is completed and the positional deviation between the substrates is detected again. In the meantime, it is also conceivable that both substrates move relative to each other due to the restoring force of the elastic member, and the substrates move relative to the correction movement amount. Then, when both the substrates are moved relative to each other by the correction movement amount as described above, the correction coefficient obtained by the above equation (1) can be a numerical value smaller than 1.

  In addition, considering the above, a threshold is set for the number of alignments between substrates and the amount of positional deviation between substrates, and when the number of alignments exceeds the threshold, or the positional deviation between substrates is less than the threshold. In such a case, a correction coefficient smaller than 1 preset in the storage unit or the like may be used.

  In the above-described embodiment, every time the alignment between the first and second substrates 3 and 4 is completed, it is measured whether there is a displacement between the substrates 3 and 4. Regardless of whether or not there is a positional deviation, it is measured whether or not the positional deviation between the substrates 3 and 4 deviates from a preset allowable value, and only when the positional deviation exceeds the allowable value, You may make it align.

  In the above description, the first substrate 3 is aligned with the second substrate 4, but the positioning of the first and second substrates 3 and 4 is relative. Therefore, the second substrate 4 may be aligned with the first substrate 3.

  In the above-described embodiment, the example of the positional deviation correction in the alignment performed in a state where the frictional force in the alignment direction by the spacer acts between the two substrates has been described. It can also be applied to alignment in a state where the two substrates are in contact with each other, and alignment in a state where the two substrates are in contact with and overlap both the liquid crystal and the sealant. In short, the present invention is applicable as long as the alignment is performed in a state where a frictional force in the alignment direction acts between the two substrates.

In the above embodiment, the liquid crystal is dropped in advance on the first substrate, and the first substrate and the second substrate are bonded together in a decompressed chamber. The present invention can be applied even when a liquid crystal display panel is manufactured by injecting liquid crystal into a gap between the substrates after bonding the substrates under atmospheric pressure.
Further, although the image processing unit is provided separately from the control device, it may be provided in the control device.

  In addition, the first substrate is held on the first holding table by vacuum suction, but may be held only by the frictional force between the holding surface of the first holding table and the first substrate. Good.

  Further, since the two substrates are bonded together in a chamber under vacuum decompression, the holding force of the first substrate vacuum-adsorbed at the time of bonding is lowered, and the first substrate is displaced on the first holding table. However, if the two substrates are held with electrostatic force and almost the same holding force, one of the substrates will be displaced at the time of alignment. Since the relative shift amounts are the same, if the correction movement amount is calculated based on the positional shift amount, it is possible to perform alignment with high accuracy as in the above embodiment.

  If the holding force of one of the substrates is made weaker than the holding force of the other substrate, it is possible to specify the substrate that shifts during alignment.

  In addition, the example in which the two substrates of the first substrate and the second substrate are bonded together has been described, but the present invention is not limited to this, and one or more other substrates are further added to the bonded two substrates. The present invention can also be applied to an adhesive that is bonded together with a liquid crystal sealed between them using a sealant.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows schematic structure of the assembly apparatus of the liquid crystal display panel which concerns on one embodiment of this invention. Sectional drawing of the bonding apparatus which bonds two board | substrates. The block diagram of a control system. The flowchart which shows a part of process when bonding two board | substrates together. The flowchart which shows the process of the continuation of FIG. The expanded sectional view which shows a part of liquid crystal display panel which formed the spacer with the resist pattern.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... 1st board | substrate, 4 ... 2nd board | substrate, 5 ... Sealing agent, 8 ... Liquid crystal, 11 ... Bonding apparatus, 15 ... 1st holding table (holding apparatus), 18 ... 2nd holding table (holding) Device), 21 ... imaging device, 22 ... first imaging camera, 23 ... second imaging camera, 31 ... image processing unit, 32 ... control device, 33 ... arithmetic processing unit, 34 ... storage unit, 35 ... drive unit .

Claims (9)

Contacting two substrates through a sealant or a liquid substance;
Determining the amount of positional deviation between the two substrates in contact;
Comprising a step of correcting the positional deviation of these two substrates by moving at least one of the two substrates in the correction movement amount obtained by multiplying the compensation coefficient to the positional deviation amount,
When correcting the positional deviation of the two substrates in contact with each other a plurality of times, the correction coefficient is K, the correction movement amount of the previous substrate is M, the previous deviation amount of the two substrates is δn, and at least one of them is corrected. If the current shift amount after the substrate is moved by the correction movement amount M is δm,
The method for bonding substrates, wherein the correction coefficient K is K = M / (δn−δm) . Applying a sealing agent for sealing a liquid substance to either one of two substrates, and bonding the two substrates together with this sealing agent,
A step of holding one substrate and the other substrate apart in the vertical direction;
Imaging two held substrates and determining the amount of positional deviation between the two substrates based on the imaging results;
Aligning the two substrates based on the amount of misalignment, and then contacting the substrates via the sealant or liquid material;
Imaging the two substrates in contact and determining the amount of positional deviation between the two substrates;
Correction moving amount obtained by multiplying the compensation coefficient to the displacement amount of the contacted two substrates by moving at least one of said two substrates comprises a step of correcting the positional deviation of the substrate,
When correcting the positional deviation of the two substrates in contact with each other a plurality of times, the correction coefficient is K, the correction movement amount of the previous substrate is M, the previous deviation amount of the two substrates is δn, and at least one of them is corrected. If the current shift amount after the substrate is moved by the correction movement amount M is δm,
The method for bonding substrates, wherein the correction coefficient K is K = M / (δn−δm) . 2. A measuring step for confirming whether or not the two substrates are displaced after at least one of the two substrates is moved to correct the positional displacement of the substrates. Or the bonding method of the board | substrate of Claim 2 .   The correction movement amount of the substrate when correcting the positional deviation of these substrates by moving at least one of the two substrates is the deviation if there is a deviation between the two substrates after the correction movement. 3. The method for bonding substrates according to claim 1, wherein the amount is a movement amount that cancels the amount.   An upper limit value and a lower limit value are set for the correction coefficient K, and when the correction coefficient K is smaller than the lower limit value or larger than the upper limit value, the lower limit value or the upper limit value is used as the correction coefficient K. The method for bonding substrates according to claim 1 or 2, characterized in that: When at least one of the substrates is held via an elastic member, when the number of alignments reaches a threshold value , a correction coefficient smaller than 1 set in advance is used instead of the correction coefficient K. The method for bonding substrates according to claim 1 or 2. A bonding apparatus that applies a sealing agent for sealing a liquid substance to one of two substrates, and bonds the two substrates with the sealing agent,
A holding device for holding one substrate and the other substrate apart from each other in the vertical direction, and driving the substrates relatively in the X, Y, Z, and θ directions to bond the two substrates;
An imaging device for imaging two substrates held by the holding device;
Then the positional displacement amounts of the two substrates on the basis of the imaging result of the imaging device, these substrates by moving at least one of the two substrates in the correction movement amount obtained by multiplying the compensation coefficient to the positional deviation amount Comprising a control device for correcting the positional deviation of
The control apparatus sets the correction coefficient to K, the correction movement amount of the previous substrate to M, the previous shift amount of the two substrates to δn, and the current movement after moving at least one of the substrates by the correction movement amount M. If the amount of deviation is δm,
A substrate bonding apparatus , wherein the correction coefficient K is calculated based on an equation of K = M / (δn−δm) .   An upper limit value and a lower limit value are set for the correction coefficient K, and when the correction coefficient K is smaller than the lower limit value or larger than the upper limit value, the lower limit value or the upper limit value is used as the correction coefficient K. 8. A substrate bonding apparatus according to claim 7, wherein:   When at least one of the substrates is held via an elastic member, when the number of alignments reaches a threshold value, a correction coefficient smaller than 1 set in advance is used instead of the correction coefficient K. The substrate bonding apparatus according to claim 7.

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