JP4751115B2 - Double-side grinding apparatus and double-side grinding method for square substrate - Google Patents

Description

  The present invention provides a double-sided grinding apparatus and a double-sided surface of a square substrate that simultaneously grinds both sides of a square substrate such as a glass substrate, a quartz substrate, a sapphire substrate, a GaAs substrate, and a silicon substrate to flatten the substrate and reduce its thickness. The present invention relates to a planarization method. In particular, this double-sided grinding apparatus for a rectangular substrate is a glass plate for a liquid crystal display device in which liquid crystal is injected between glass plates, or a display in which an electrode is provided on the inner surface of a glass plate and liquid crystal is injected between the glass plates. Used when grinding both sides of a glass substrate for equipment.

  A glass plate for a liquid crystal display device in which liquid crystal is injected between glass plates, or a glass substrate for a display device in which an electrode is provided on the inner surface of the glass plate and liquid crystal is injected between the glass plates is known. Used on the board. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3.)

  Usually, the square glass plate used for this liquid crystal display panel is reduced in thickness by grinding or lapping the surface, and further, the ground surface or lapping surface is flattened by etching or double-side polishing. (For example, see Patent Document 4, Patent Document 5, Patent Document 6, Patent Document 7, and Patent Document 8.)

  When the glass plate for the liquid crystal display device is a liquid crystal display plate having a relatively small size of 1 to 6 inches such as a mobile phone, a portable liquid crystal television, a portable game machine, and a portable terminal, the fluctuation width of the thickness distribution is small. However, it was not a problem as much as the left, but as the size of 12 inch, 14 inch, 17 inch is large like the liquid crystal display plate of portable liquid crystal personal computer, desktop personal computer, digital television, the thickness of the glass plate is thinner and the thickness distribution The swing width is required to be 2 to 50 μm.

  Therefore, in order to obtain a laminated plate of a glass plate for a 12 to 17 inch liquid crystal display device having a thickness of about 1 mm, a glass plate for a liquid crystal display device of about 1.2 mm (thickness 0.6 mm glass plate / 5 μm liquid crystal layer / thickness). In order to grind both sides of a 0.6 mm glass plate laminate) by 0.1 mm, in a double-sided grinding apparatus using a cup wheel type grindstone described in Patent Document 6, a concave lens having a dent at the center and a thick corner It becomes a glass substrate for a display device having a thick thickness distribution, and cannot be practically used. In addition, since the grindstone pressure applied to the liquid crystal sandwiched between the glass plates is unevenly distributed, the liquid crystal streaks often remain on the ground glass plate for a liquid crystal display device.

  A glass plate for a liquid crystal display device is housed in a pocket portion provided at the center of a linearly moving stainless steel carrier belt described in Patent Document 4 and Patent Document 5, and the same belt belt is swung in the left-right direction while moving the same. In the method of performing both-side grinding by passing between flat grindstones rotating at the axis, a bulge remains in the central portion of the glass plate for a liquid crystal display device, and the fluctuation width of the thickness distribution is 75 to 100 μm, which is a non-standard product.

Furthermore, since the double-sided lapping described in Patent Document 7 becomes a glass substrate for a display device having four thick corners, it is necessary to perform edge grinding of the glass plate for a liquid crystal display device before lapping.
JP 2003-255291 A Japanese Patent Laid-Open No. 2004-21016 JP 2005-3845 A JP-A-11-123642 JP 2001-001241 A JP 2004-098198 A JP 2004-243469 A JP 2000-273443 A

  The present invention improves the drawbacks of the double-sided grinding apparatus described in Patent Document 4 and Patent Document 5 described above, in which a square substrate is held on a linearly moving carrier belt, and this square substrate is ground on both sides with a pair of rotating grindstones. An object of the present invention is to provide a double-side grinding apparatus for a square substrate that does not require pre-processing of edge processing. Another object of the present invention is to provide a glass plate for a 12 to 17 inch liquid crystal display device having a thickness fluctuation width of 50 μm or less and a thickness of about 1.0 to 1.26 mm.

The invention of claim 1
A linearly movable carrier belt provided with a substrate storage pocket in the center,
A lateral movement mechanism of the linearly movable carrier belt;
A pair of eccentric square grinding flat wheels with their rotational axes removed from the central axis of the grindstone, and a pair of eccentricity arranged such that the grinding surfaces of the pair of square grinding flat grinding wheels are parallel and rotate around different axes. Square grinding flat whetstone,
A lifting mechanism and a rotation drive mechanism of the eccentric angular grinding wheel, and a grinding fluid supply means for supplying a grinding fluid to a surface where the substrate accommodated in the substrate storage pocket and the eccentric angular grinding flat grindstone contact each other;
The double-sided grinding apparatus of a square-shaped board | substrate provided with this is provided.

  According to the second aspect of the present invention, a rectangular glass substrate is held on a linearly moving carrier belt, and the substrate is passed between a pair of eccentric angular grinding grindstones rotating in the opposite direction, so that both surfaces of the glass substrate are simultaneously formed. In the method for grinding a glass substrate to be ground, the pair of eccentric square-shaped grinding grindstones are arranged to rotate with different axes with the grinding surfaces parallel to each other, and the glass substrate is disposed between the eccentric square-shaped grinding grindstones. The glass substrate is ground for a certain period of time, and both sides of the glass substrate are ground by intermittently reciprocating left and right of the linearly moving carrier belt during grinding of the glass substrate. A method is provided.

  Since both surfaces of the square substrate are ground with eccentric square grinding flat grindstones that rotate in opposite directions while swinging the substrate in the left-right direction, the difference in thickness between the four corners of the ground substrate and the thickness at other locations Is a square substrate having a thickness distribution of 50 μm or less. In addition, since the axis of each other is not concentric and the rotation direction of the eccentric angular grinding flat grindstones of the spaced apart axes is opposite, the square substrate is removed from the pocket portion of the linearly moving carrier belt during grinding. Never jump out.

(Example)
Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a flow chart for flattening a square substrate using a double-side flattening device, FIG. 2 is a sectional view of the substrate double-side grinding device shown in FIG. FIG. 4 is a cross-sectional view in which a part of the double-side polishing apparatus shown in FIG. 1 is cut away, and FIG. 4 is a plan view showing the movement of the substrate and the eccentric angular grinding flat grindstone during grinding.

  In FIG. 1, a double-sided flattening apparatus 100 for a square substrate is roughly divided into a substrate having a substrate loading mechanism 200, an unloading mechanism 201, a rough grinding double-side grinding device 101, and a finish grinding double-side grinding device 102. Double-side grinding apparatus, substrate double-side polishing apparatus 103, cleaning mechanisms 300, 301, 302, substrate transport mechanism 400, grinding fluid supply means 500, abrasive supply mechanism 510, and diamond for dressing an eccentric square-shaped grinding flat grindstone The dresser 600 includes a dresser 601 for dressing a polishing cloth.

  1, 2, and 3, the double-sided flattening apparatus 100 for a square substrate has a concentric axis center for an eccentric angular grinding flat grindstone whose rotational axis is located 10 to 80 mm away from the center point of the flat grindstone. Substrate double-sided grinding apparatus 101 comprising a pair of eccentric square grinding flat grindstones 1 and 2 that are rotated by rotating shafts 1a and 2a so that the surfaces of the square grinding flat grindstones face each other 20 to 160 mm apart from each other. , 102 and a carrier belt 4 for transporting a substrate 3 having a square shape (rectangular shape), which is a workpiece, between these eccentric square grinding flat grindstones 1 and 2, and a substrate 3 before processing in a pocket of the carrier belt 4 A loading mechanism 200 to be held by the portion 4a, an unloading mechanism 201 for taking out the square substrate 3 after grinding from the carrier belt 4, a grinding fluid supply means 500, and cleaning means 300, 301, 30. It is equipped with a.

The eccentric square grinding flat grindstones 1 and 2 are arranged so that their grinding surfaces 1b and 2b are parallel to each other and are close to each other perpendicular to both surfaces of the carrier belt 4, and the prime mover M ₁ , pulley 12b, gear The rotary drive device 12 provided with 12a, 12c and the like can be rotated in opposite directions at a predetermined rotational speed, for example, 10 to 180 cm ⁻¹ .

The eccentric square grinding flat grindstones 1 and 2 can be raised and lowered at a predetermined speed by a lifting device 13 equipped with a prime mover M ₂ , a slider 13 a, a guide rail, etc., and a grinding allowance is set with a predetermined accuracy. It is configured to be able to. The interval (original position) between the eccentric square-shaped grinding grindstones 1 and 2 before processing is adjusted by the thickness of the glass substrate 3 to be processed. The size of the eccentric square-shaped grinding flat grindstones 1 and 2 is preferably 1.3 to 2.0 times similar to that of the square-shaped substrate that is the object to be ground.

Since the eccentric angle-shaped grinding flat grindstone 1 and the eccentric angle-shaped grinding flat grindstone 2 are rectangular shapes having the same dimensions, the eccentric angle-shaped grinding flat grindstone 1 will be described. As shown in FIG. 4, the eccentric square grinding flat grindstone 1 is fixed to the hollow spindle 21 via an inverted dish-shaped grindstone support washer 1 a so that the flat surface of the grindstone layer faces the substrate side. A space formed by the eccentric square-shaped grinding flat grindstone 1 and the inverted dish-shaped grindstone support washer portion 1a forms a grinding fluid storage chamber 1c. The eccentric angular grinding flat grindstone 1 is fixed to the hollow spindle 21 via an inverted dish-shaped grindstone support washer 1a so that the position 10 to 80 mm away from the diagonal intersection (center point) is the rotation axis. . The pair of eccentric square grinding flat grindstones 1 and 2 are installed so as to be point-symmetric with respect to the carrier belt 4 with their grinding surfaces parallel. Therefore, the distance between the rotation axes of the pair of eccentric square-shaped grinding flat grindstones 1 and 2 is 20 to 160 mm. The eccentric square-shaped grinding flat grindstones 1 and 2 rotate in opposite directions to each other at 10 to 180 min ⁻¹ .

  The eccentric square-shaped grinding flat grindstone 1 is provided with a plurality of through-holes 1d through which the grinding liquid is fed in the thickness direction. The grinding liquid in the storage tank 501 is supplied by the pump P to the pipe 504 provided in the hollow shaft of the hollow spindle through the pipe 502 and the rotary joint 503 and guided to the grinding liquid storage chamber 1c. The grinding fluid in the grinding fluid storage chamber 1c is guided between the substrate 3 and the eccentric angular grinding flat grindstone 1 through the through hole 1d.

  The grinding head H, the slider 13a, and the like are supported by the mounting frame 16, and a slider 17b provided at the lower portion of the mounting frame 16 moves on the guide rail 17a provided in the column 15 in the front-rear direction. The grinding head H can be moved forward and backward in a direction orthogonal to the left-right feed direction of the carrier belt 4. The grindstone dresser 600 is fixed to a rotating arm, and rubs the eccentric square grinding flat grindstones 1 and 2 and the surfaces 1b and 2b when the grinding head H slides on the guide rail 17a and retracts from the carrier belt. It is fixed. The grinding start point is set such that the distance between the square grinding flat grindstone 1 and the square grinding flat grindstone 2 is 0.05 mm to 0.1 mm larger than the thickness of the square substrate 3 conveyed by the carrier belt 4. Is preferred.

  In order to efficiently grind the glass substrate, it is preferable to perform multiple times of grinding such as rough grinding, finish grinding, or rough grinding, intermediate finish grinding, and finish grinding. The count, concentration, and bond hardness of the grindstone are selected depending on the type of substrate and the required surface roughness. For example, in the case of two-stage grinding as the eccentric angular grinding flat grindstone 1, a resinoid bond grindstone having diamond abrasive grains of # 100 to # 325 on a grindstone for rough grinding, and # 600 to a grindstone for finish grinding. A metal bond grindstone with # 2000 diamond abrasive grains or a resinoid bond grindstone with # 600 to # 1500 diamond abrasive grains is used. Alternatively, in the case of three-stage grinding, a resinoid bond grindstone provided with diamond abrasive grains of # 100 to # 325 is provided on a grindstone for rough grinding, and a diamond abrasive grain of # 600 to # 2000 is provided on a grindstone for intermediate finish grinding. The resinoid bond grindstone is a metal bond grindstone provided with # 4000 to # 8000 diamond abrasive grains on a grindstone for finishing grinding.

  In two-stage grinding, the grinding allowance in rough grinding should be 60 to 95% of the total grinding allowance to ensure the balance of grinding speed and to eliminate surface defects such as cracks on the glass surface. It is preferable to complete grinding in a short time as a whole without causing it to occur, and more preferably 75 to 85%. In the case of grinding in three stages, it is preferable that the distribution of the total grinding thickness is 60 to 85% for rough grinding, 35 to 13% for intermediate finish grinding, and 5 to 2% for precision grinding. When changing from a 0.5 mm thick glass plate to a 0.3 mm thick glass substrate (0.2 mm grinding allowance), in the case of two-stage grinding, it is set to 0.12 mm or more by rough grinding and three-stage grinding. Then, it is preferable to set it to 0.12-0.18 mm by group grinding, 0.026-0.07 mm by medium finish grinding, and 0.05 mm or less by finish grinding.

The substrate transport mechanism 400 includes an endless belt-like carrier (carrier belt) 4 formed of a belt-like belt material such as stainless steel and glass fiber reinforced resin, driving rolls 401 and 402, tension rolls 403 and 404, and an auxiliary roll 405. , 406, a prime mover M ₃ that rotates the drive rolls 401, 402 so that the carrier belt 4 can be stopped at a desired position and can travel at a desired speed, a brake control device (not shown), and the like. The endless carrier belt 4 is stretched around a drive roll, a tension roll, and an auxiliary roll, and travels in the right direction or the left direction by the rotation of the drive roll. And when conveying the glass substrate 3, the carrier belt 4 can be stopped at a desired position and can run at a desired speed.

The traveling speed of the carrier belt 4 that accommodates the square substrate 3 passing between the pair of rotating eccentric grinding flat grindstones 1 and 2 is the difference between the thickness of the glass substrate 3 to be used and the thickness of the square substrate to be obtained (grinding). (Thickness amount) and the required surface roughness after grinding. For example, to grind a 14-inch liquid crystal display glass laminate having a laminate thickness of about 0.6 mm to obtain a glass laminate substrate for a liquid crystal display having a thickness of about 0.4 mm, with the total grinding thickness amount on both sides being 0.2 mm. , a rectangular shape eccentric grinding flat grindstone 20 inch 100～180Min ^-1 in rough grinding device, by rotating the finishing grinding wheel at about 20～50Min ^-1, about the running speed at the time of swinging of the carrier belt 4 80～200Cm / Min, and the feed until loading or unloading is about 1 minute interval. The distance between the rotation axes of the pair of eccentric square-shaped grinding flat grindstones 1 and 2 is preferably 40 to 100 mm. Further, the cutting amount of the substrate of the eccentric square grinding flat grindstone 1 in the rough grinding device 101 is 2.5 to 5 μm / second, and the cutting amount of the eccentric square grinding flat grindstone 1 in the finishing rough grinding device 102 is 0.5. It may be about ˜2 μm / second.

  The carrier belt 4 is driven in the left-right direction with a predetermined amplitude (25 to 100 mm) and a predetermined cycle (2 to 20 times / min) centered on a predetermined position by forward and reverse driving of the drive rolls 401 and 402. Can swing forward and backward. In addition, the arrow has shown the traveling direction when the glass substrate 3 is conveyed. The carrier belt 4 is formed with a plurality of pocket portions 4a that are slightly larger than the outer shape of the rectangular substrate 3 at a central portion in the width direction and at a predetermined interval of 0.5 to 1 mm in the length direction. Note that the thickness of the substrate 3 is larger than the thickness of the carrier belt 4 so that when the substrate 3 is fitted into the pocket portion 4 a, both surfaces of the substrate 3 protrude from both surfaces of the carrier belt 4 beyond the grinding allowance. It is getting bigger.

  Since both surfaces of the square substrate 3 are ground with the grinding flat grindstones 1 and 2 rotating on the eccentric shaft while the carrier belt 4 is intermittently swung in this way, the grinding flat grindstones 1 and 2 are locally worn. As a result, the life of the grindstone can be improved, and the flat shape of the surface due to wear of the grindstone can be prevented from being deformed, so that the flatness of the substrate 3 and the uniformity of the thickness can be improved. When the substrate 3 is roughly ground to a desired thickness, the carrier belt 4 stops swinging, and the ground grindstones 1 and 2 are retracted from the surface of the square substrate 3 by about 0.05 mm to 0.1 mm, respectively. To do.

The cleaning mechanisms 300, 301, and 302 are used to remove fine particles attached to the surface of the substrate 3 between the rough grinding apparatus 101 and the finish grinding apparatus 102, between the finish grinding apparatus 102 and the polishing apparatus 103, and after the polishing apparatus 103. Installed respectively to remove glass powder and abrasive grains. As the cleaning mechanisms 300 and 301 after the substrate grinding process and the cleaning mechanism 302 after the polishing process, means such as a T-die for spraying a pressurized water flow onto the substrate 3 from both sides and a plurality of spray nozzles may be employed. Note that a mechanism for cleaning the substrate with a roll brush may be provided before the cleaning mechanism 302 after polishing the substrate.

The loading mechanism 200 and the unloading mechanism 201 include a stacker for storing the substrate 3 and an elevating mechanism for moving the stacker up and down. The loading mechanism 200 raises the glass substrate 3 with a stacker just before the upstream side of the carrier belt 4 with respect to the traveling direction of the carrier belt 4 with respect to the double-side grinding apparatus 101 for rough grinding, and fits it into the pocket portion 4 a of the carrier belt 4. The unloading mechanism 201 is provided on the downstream side with respect to the traveling direction of the carrier belt 4 after the cleaning mechanism 302 behind the polishing apparatus 103, and the square substrate 3 is lowered by a stacker and removed from the pocket portion 4a of the carrier belt 4. .

  As shown in FIG. 4, the polishing apparatus 103 arranges a pair of polishing surface plates 103a and 103b each having a polishing cloth affixed to the surface of a disk-like support body in a vertical direction with a carrier belt 4 sandwiched between concentric axes. The surface plates 103a and 103b are supported by hollow rotary shafts 103c and 103d. The abrasive is supplied to the pipe 604 provided in the hollow rotary shafts 103c and 103d via the pipe 602 and the rotary joint 603 by the pump P to wet the polishing cloth of the polishing surface plate. The polishing surface plate is supported by a mounting frame 160, and a slider 170b provided at the lower portion of the mounting frame 160 can move in the front-rear direction on a guide rail 170a provided in the column 150. The polishing surface plate can be moved forward and backward in a direction perpendicular to the left and right feed direction of the carrier belt 4. The polishing cloth dresser 610 is fixed to the rotary arm 611 and fixed to a position where the polishing surface plate rubs on the polishing cloth surface of the polishing surface plate when the polishing surface plate slides on the guide rail 170a and retreats from the carrier belt 4. Yes.

  As the abrasive, ceria, alumina, diamond, or silica-based abrasive slurry is used as the abrasive. The polishing agent varies depending on the type of substrate of the object to be polished, but the glass substrate is a ceria-based abrasive slurry, the silicon substrate is a colloidal silica-based slurry, the sapphire substrate is an alumina-based slurry and a diamond-based slurry. Is preferred.

The rotation axes of the pair of polishing surface plates 103a and 103b are preferably concentric. The rotation direction is preferably the reverse direction, and the rotation direction of the upper polishing surface plate 103a of the carrier belt 4 and the upper grinding flat grindstone 1 of the grinding device is the same rotation direction, and the lower polishing surface plate 103a and lower side The rotation direction with the grinding flat grindstone 2 is preferably the same rotation direction. The number of rotations of the polishing surface plate is preferably 50 to 300 min ⁻¹ , and the pressure applied to the substrate 3 of the polishing surface plate is preferably ²⁰ to 100 g / cm ² . When polishing the substrate, the carrier belt 4 is intermittently swung from side to side. The amplitude and cycle of the swing of the carrier belt 4 are the same as during grinding. The removal allowance for the substrate 3 is preferably 2 to 10 μm.

  The amount of polishing cut into the rectangular substrate 3 is adjusted by raising and lowering the air cylinder 180. The time required for the glass substrate 3 to remain between the polishing surface plates is about 10 seconds to 30 seconds for the substrate 3 to be polished to a desired thickness. Keep away. Since the polishing time is shorter than the time required for rough grinding, even if the polishing surface plate is moved away from the carrier belt 4, the rough grinding of the substrate by the rough grinding eccentric grindstones 1 and 2 is continued. After the substrate is polished, the substrate 3 is determined at the unloading position by the forward traveling of the carrier belt 4. The substrate 3 polished during the running is cleaned.

  At the unloading position, the rectangular substrate 3 is taken out from the pocket portion 4 a of the carrier belt 4 by lowering the stacker of the unloading mechanism 201.

  Thus, one cycle of the flattening operation of the square substrate 3 is completed.

  As the square substrate 3, glass substrates such as soda lime silica glass, borosilicate glass, aluminosilicate glass, aluminoborate glass, non-alkali low expansion glass, high strain point high expansion silicate glass, crystallized glass, etc. In addition, a rectangular substrate such as a quartz substrate, a sapphire substrate, a GaAs substrate, or a silicon substrate is a workpiece.

  Next, an example of planarization will be described by taking a liquid crystal display panel laminate as an example. The 14-inch liquid crystal display panel laminate 3 used had a thickness of 1.005 mm before processing (a laminate of glass plate 0.5 mm / liquid crystal film 0.005 mm / glass plate 0.5 mm), and the allowance was 0 on each side. .2 mm, 0.4 mm in total on both sides, and pass if the thickness fluctuation width after flat processing is 50 μm or less.

Example 1
When the liquid crystal display panel laminate 3 is carried into the eccentric grinding flat grindstones 1 and 2, the distance between the eccentric grinding flat grindstones 1 and 2 is 1.0 mm, and the distance from the center of the eccentric grinding flat grindstone to the spindle axis is 25 mm (spindle The distance between the shafts was 50 mm), the rocking width of the carrier belt 4 was 150 mm, the rocking frequency was 12 times / minute, and the rocking feed speed was 360 mm / second. When the substrate 3 is loaded into the eccentric grinding flat grindstones 1 and 2, the interval between the 20 inch eccentric grinding flat grindstones 1 and 2 is 1.0 mm, and the # 320 resinoid diamond eccentric grinding flat grindstone 1 for rough grinding is used. The rotational speed of No. 2 was 120 min ⁻¹ , and the rotational speed of the # 800 metal bond diamond eccentric grinding flat grindstones 1 and 2 for finish grinding was 50 min ⁻¹ . The rotation direction of the eccentric grinding flat grindstones 1 and 2 was the reverse direction. The rough grinding time was 50 seconds, and the finish grinding time was 30 seconds.

Further, the polishing surface plates 103a and 103b having a surface plate diameter of 450 mm are provided on concentric axes, the rotation speed is 100 min ⁻¹ , the rotation direction is the reverse direction, the applied pressure is 50 g / cm ² , and the polishing time is 25 seconds. And a ceria-based slurry was used.

In the obtained flattened substrate, the thickness of the laminate for liquid crystal display plate after finish grinding is about 0.609 mm, the maximum thickness fluctuation width is 23 μm, and the thickness of the laminate for liquid crystal display plate after polishing is , About 0.604 mm, and the maximum thickness fluctuation width was 16 μm. The thickness of the four corners of the flattened substrate was not particularly high compared to other parts.

Example 2
When the liquid crystal display panel laminate 3 is carried into the eccentric grinding flat grindstones 1 and 2, the distance between the eccentric grinding flat grindstones 1 and 2 is 1.0 mm, and the distance from the center of the eccentric grinding flat grindstone to the spindle axis is 35 mm (spindle The distance between the shafts was 70 mm), the rocking width of the carrier belt 4 was 150 mm, the rocking frequency was 12 times / minute, and the rocking feed speed was 360 mm / second. When the substrate 3 is loaded into the eccentric grinding flat grindstones 1 and 2, the interval between the 20 inch eccentric grinding flat grindstones 1 and 2 is 1.0 mm, and the # 320 resinoid diamond eccentric grinding flat grindstone 1 for rough grinding is used. The rotational speed of 2 is 120 min ⁻¹ , the rotational speed of # 600 resinoid diamond eccentric grinding flat grindstones 1 and 2 for medium finish grinding is 60 min ⁻¹ , and the # 2000 metal bond diamond eccentric grinding flat grindstone 1 for finishing grinding 1 The rotational speed of 2 was 30 min ⁻¹ . The rotation direction of the eccentric grinding flat grindstones 1 and 2 was the reverse direction. The rough grinding time was 45 seconds, the intermediate finish grinding time was 25 seconds, and the finish grinding time was 20 seconds.

Further, the number of rotations on the concentric axes of the polishing surface plates 103a and 103b having a surface plate diameter of 450 mm is 120 min ⁻¹ , the rotation direction is the reverse direction, the applied pressure is 80 g / cm ² , the polishing time is 20 seconds, and the ceria type A slurry was used.

The obtained flattened substrate has a thickness of the liquid crystal display plate laminate after finish grinding of about 0.607 mm, a maximum thickness fluctuation width of 12 μm, and the thickness of the liquid crystal display plate laminate after polishing is About 0.605 mm, the maximum thickness fluctuation width was 8 μm. The thickness of the four corners of the flattened substrate was not particularly high compared to other parts, and a flat laminate for a liquid crystal display panel was obtained.

  The method of carrying out double-side grinding while swinging the glass laminate for a liquid crystal display panel in the left-right direction using the pair of eccentric grinding flat grindstones of the present invention can provide a glass laminate for a liquid crystal display panel with a uniform thickness distribution. .

FIG. 5 is a flow chart for flattening a square substrate using a double-side flattening device. It is sectional drawing which notched a part of substrate double-sided grinding apparatus shown in FIG. It is a top view which shows a motion of the board | substrate and the eccentric angle-shaped grinding flat grindstone when carrying out double-side grinding of the board | substrate. It is sectional drawing which notched a part of double-side polish apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Eccentric grinding flat grindstone Triangular board | substrate 100 Double-sided surface flattening apparatus 101 Double-sided grinding apparatus for rough grinding 102 Double-sided grinding apparatus for finish grinding 103 Double-sided polishing apparatus 200 Substrate loading mechanism 201 Substrate unloading mechanism 300 Cleaning Mechanism 400 Substrate transport mechanism 4 Carrier belt 4a Pocket

Claims (2)

A linearly movable carrier belt provided with a substrate storage pocket in the center,
A lateral movement mechanism of the linearly movable carrier belt;
A pair of eccentric square grinding flat wheels with their rotational axes removed from the central axis of the grindstone, and a pair of eccentricity arranged such that the grinding surfaces of the pair of square grinding flat grinding wheels are parallel and rotate around different axes. Square grinding flat whetstone,
A lifting mechanism and a rotation drive mechanism of the eccentric angular grinding wheel, and a grinding fluid supply means for supplying a grinding fluid to a surface where the substrate accommodated in the substrate storage pocket and the eccentric angular grinding flat grindstone contact each other;
A double-sided grinding apparatus for a square substrate.   A glass substrate grinding method in which a square-shaped glass substrate is held on a linearly movable carrier belt, and the substrate is passed between a pair of eccentric square-shaped grinding grindstones rotating in the opposite direction to simultaneously grind both surfaces of the glass substrate. In the above, the pair of eccentric square grinding grindstones are arranged so that their grinding surfaces are parallel and rotate with different axes, and the glass substrate is kept between the eccentric square grinding grindstones for a certain period of time, A method for grinding a square glass substrate, wherein both sides of the glass substrate are ground by intermittently reciprocating left and right of the linearly moving carrier belt during grinding of the glass substrate.

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