JP2008290190A - Polishing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing machine with a polishing sheet capable of removing only abnormal projections without damaging a film with normal thickness in the condition of the polishing sheet brought into contact with the surface of a glass substrate. <P>SOLUTION: In the polishing machine polishing the film of the surface of the glass substrate W with the polishing sheet 23 by moving the polishing plate 20 relative to the glass substrate W in a plane while pushing and pressing the polishing plate 20 constituted by affixing the polishing sheet 23 to a polishing platen face 20a onto the surface of the glass substrate W on which the film is formed, primary particle size of abrasive grains included in the polishing layer of the polishing sheet 23 is 10 to 50 nm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing machine for polishing a colored film formed on a glass substrate such as a color filter for a liquid crystal display device.

For example, Patent Document 1 has been proposed as a polishing machine for the colored layer of the color filter described above.
In this polishing machine, a rectangular polishing plate whose long side is longer than the short side of the glass substrate is placed on the surface of the stationary square glass substrate (color filter) on which the colored layer is formed. Placed parallel to the side, while pressing the glass substrate surface with the polishing plate, the polishing plate is rotated eccentrically around the vertical direction of the glass substrate to swing the polishing plate in the short side direction of the glass substrate and polish The color filter surface is polished by moving the plate in the long side direction of the glass substrate.
According to this polishing machine, an advantage that the entire surface of the glass substrate can be uniformly polished is obtained as compared with a conventional Oscar type polishing machine.

  Incidentally, as shown in FIG. 8, the color filter CF for a liquid crystal panel has a structure in which a black matrix BM is formed on the surface of a flat glass substrate W, and a colored film (RGB film) is formed thereon. If foreign matter is mixed into the colored film during the manufacturing process, abnormal projections 300 may occur on the RGB film. As shown in FIG. 8, the height S2 of the abnormal protrusion 300 is generally about 10 to 40 μm while the height of the RGB film thickness S1 including the normal protrusion is generally 1.5 to 2.0 μm. If such an abnormal projection 300 is generated, the panel is stuck in the manufacturing process, which causes a display defect.

  However, conventional polishing machines are not suitable for removing such abnormal protrusions. This is because a conventional polishing machine is for entire surface polishing, and even if only abnormal protrusions are to be polished, there is a risk that even a normal film thickness portion may be removed.

Therefore, in the previously filed Japanese Patent Application No. 2007-84946, the present applicant, when the polishing plate is pressed against the glass substrate against the polishing platen surface of the polishing plate, the surface of the glass substrate precedes the polishing sheet. There has been proposed a polishing machine that optimally holds the clear run between the surface of the glass substrate and the polishing sheet by providing a clearance adjustment pad made of an elastic body that abuts and deforms in response to the pressing force.
By providing this clearance adjustment pad, the polishing sheet can be brought into contact with only abnormal projections existing on the film on the surface of the glass substrate during polishing, and can be brought into non-contact with a film having a normal thickness. It is possible to polish and remove only abnormal protrusions without reducing the normal film thickness.
For polishing such abnormal protrusions, a fixed abrasive polishing sheet having excellent grinding force embedded with diamond abrasive grains or alumina abrasive grains is used.

However, the following problems remain in the polishing with the clearance adjustment pad.
That is, since the clearance adjustment pad is made of an elastic body, the amount of deformation is not constant for each polishing, and thus it is difficult to always keep the clearance between the surface of the polishing sheet and the abnormal protrusion constant, and Further, since the thickness of the clearance adjusting pad varies from lot to lot, it is necessary to set polishing conditions (for example, to secure an optimum clearance by adjusting the polishing pressure) every time the pad is replaced, and this is a problem that polishing reproducibility is low.
In particular, diamond abrasive grains have a high abrasive hardness and a large particle diameter. Therefore, if the clearance between the surface of the glass substrate and the polishing sheet becomes too small, the normal thickness of the glass substrate surface is reduced. Abrasive grains protruding from the surface of the polishing sheet come into contact with each other to cause polishing scratches.
JP 2004-195602 A

  The present invention has been made in view of the above circumstances, and is a polishing machine capable of polishing and removing only abnormal protrusions without damaging a film having a normal thickness in a state where a polishing sheet is in contact with the surface of a glass substrate. The purpose is to provide.

  That is, the polishing machine according to claim 1 is configured such that the polishing plate is pressed against the glass substrate while pressing the polishing plate with the polishing sheet attached to the surface of the polishing platen on the surface of the glass substrate on which the film is formed. In the polishing machine that polishes the film on the surface of the glass substrate with the polishing sheet by moving in-plane, the primary particle diameter of the abrasive grains contained in the polishing layer of the polishing sheet is 10 to 50 nm. Yes.

  The invention described in claim 2 is the polishing machine according to claim 1, wherein the primary particle diameter of the abrasive grains is 10 to 20 nm.

  The invention according to claim 3 is the polishing machine according to claim 1 or 2, wherein the abrasive grains are silica particles.

  According to a fourth aspect of the present invention, in the polishing machine according to any one of the first to third aspects, the polishing sheet is attached to the polishing platen surface of the polishing plate via an elastic sheet. It is characterized by having.

  Further, the invention according to claim 5 is the polishing machine according to any one of claims 1 to 4, wherein the glass is disposed below the conveyance path for conveying the glass substrate along the surface direction. A lower surface plate on which the substrate is placed is disposed, and a polishing head for polishing the upper surface of the conveyed glass substrate is provided above the lower surface plate, and the polishing sheet is placed below the main body of the polishing head. The polishing plate as an upper surface plate is provided so as to be movable in the vertical direction, and the polishing plate is pressed against the glass substrate between the main body of the polishing head and the polishing plate, and the pressing force is adjusted. And a drive mechanism for orbitally moving the polishing head so as to include at least a movement component in an in-plane direction orthogonal to the conveyance direction of the glass substrate. It is a symptom.

  The invention according to claim 6 is the polishing machine according to any one of claims 1 to 5, wherein the glass substrate is a color filter of a display panel, and the film is an RGB colored film. It is characterized by being.

  According to invention of Claim 1, 2, the primary particle diameter of the abrasive grain (abrasive material particle) contained in the polishing layer of the polishing sheet is 10 to 50 nm, preferably 10 to 20 nm. Since it does not contain coarse particles having a particle size of several μm, unlike grains, only abnormal protrusions can be efficiently polished and removed without damaging the film on the surface of the glass substrate during polishing. For example, even if the polishing sheet comes into contact with the film surface of the glass substrate during polishing, since the abrasive grain size of the polishing sheet is extremely fine as 10 to 50 nm, the film surface is only mirror polished and Such polishing scratches do not occur.

  Moreover, according to the invention of claim 3, since silica particles are used as abrasive grains, as described above, in addition to being ultrafine particles, silica particles are compared to diamond abrasive grains or alumina abrasive grains. Since the abrasive hardness is considerably low, the occurrence of polishing flaws can be prevented more reliably.

  According to the invention described in claim 4, since the elastic sheet is interposed between the polishing surface plate and the polishing sheet, the pressing force applied to the glass substrate is dispersed by the cushion of the elastic sheet, and is uniform. Since polishing is performed with this polishing pressure, polishing spots can be prevented.

  According to the invention described in claim 5, the polishing plate is provided on the polishing head so as to be movable in the vertical direction, and the polishing plate is pressed against the glass substrate by the press adjusting mechanism. The pressing force can be adjusted to a suitable pressing force that allows efficient polishing without scratching the surface.

  Furthermore, according to the sixth aspect of the present invention, it is possible to efficiently remove abnormal protrusions generated on the colored film of the color filter without damaging the surface of the color filter.

Hereinafter, an embodiment of a polishing machine of the present invention will be described with reference to FIGS.
The polishing machine of the present embodiment is for polishing a colored film (RGB film) of a color filter for a liquid crystal display device, and FIG. 1 is a schematic diagram of a production line for a glass substrate W equipped with the polishing machine of the present embodiment. FIG. 2 is a side view showing the main part configuration, FIG. 3 is a sectional view of the lower part of the polishing plate as viewed from the side in the transport direction of the glass substrate, and FIG. FIG. 5 is a cross-sectional view showing the structure of the polishing sheet, FIG. 6 is a view of the polishing plate as viewed from below, and FIG. 7 is a glass showing the structure of the polishing head. It is sectional drawing seen from the side of the conveyance direction of a board | substrate, (a) is a figure which shows the state before pressing a polishing plate against a glass substrate, (b) is a figure which shows the state which pressed the polishing plate against the glass substrate. It is.

  1 and 2, reference numeral 1 denotes a conveyance conveyor (conveyance path) that conveys a glass substrate W (in this embodiment, a color filter) in the direction of arrow A along the surface direction, and reference numeral 3 denotes a lower part of the conveyance conveyor 1. The lower surface plate on which the glass substrate W is placed during polishing, the reference numeral 10 is disposed above the lower surface plate 3, and a polishing head for polishing the upper surface of the conveyed glass substrate W, the reference numeral 20 is this A polishing plate serving as an upper surface plate provided in the main body 11 of the polishing head 10.

This polishing machine (portion represented by the polishing head 10) moves the polishing plate 20 in-plane with respect to the glass substrate W while pressing the polishing plate 20 against the surface of the glass substrate W on which the RGB film is formed. Thus, the colored film (RGB film) on the surface of the glass substrate W is polished.
The glass substrate W has a rectangular flat plate shape, and is conveyed from the upstream side to the lower side of the polishing head 10 with one short side at the front end in a posture in which the long side is parallel to the conveyance direction A. While being polished by the polishing head 10, it is conveyed to the downstream side with the same posture and speed.

  As shown in FIGS. 3 and 4, the lower surface 20a (polishing surface 20a) of the polishing plate 20 is fixed with a double-sided tape or the like through an elastic sheet (urethane rubber, urethane sheet, etc.) 21 having a thickness of about 0.9 mm. An abrasive polishing sheet 23 is affixed. Incidentally, the urethane sheet has a hardness of 10 to 20 °, a compression rate of 20 to 50%, and a compression modulus of 94 to 96%.

  In the present embodiment, when the fixed abrasive polishing sheet 23 is attached, the edge of the elastic sheet 21 is covered with the fixed abrasive polishing sheet 23 so that the corners of the elastic sheet 21 are rounded. As a result, when the glass substrate W is transported, the leading edge of the glass substrate W hits the edge of the fixed abrasive polishing sheet 23, and the edge of the crow substrate W is damaged or locally. The inconvenience of being polished can be avoided.

By the way, as shown in FIG. 5, the fixed abrasive polishing sheet 23 has a polishing layer 26 having a thickness of about 5 μm formed on one surface of a substrate 24 made of a plastic film such as polyester having a thickness of about 75 μm. The polishing layer 26 is formed by dissolving a binder and abrasive grains in an organic solvent and dispersing them to prepare a coating liquid, which is applied to the substrate 24 by a coating means and dried. Can do.
In the present embodiment, silica particles are used as the abrasive grains (abrasive particles) 27 that form the polishing layer 26, and epoxy resin is used as the binder.

In the fixed abrasive polishing sheet 23 of the present embodiment, fine particles having a particle diameter (primary particle diameter) of 10 to 50 nm are used as the abrasive grains 27 included in the polishing layer 26.
This is because if the particle size of the abrasive grains 27 is smaller than 10 nm, the polishing power decreases, the desired polishing effect cannot be obtained, and it becomes difficult to polish and remove abnormal protrusions. When the particle size is larger than 50 nm, This is because a polishing flaw may occur on the film surface of the glass substrate W during polishing. Therefore, in the present embodiment, the particle diameter of the abrasive grains 27 included in the polishing layer 26 is 10 to 50 nm, preferably 10 to 20 nm.

  Table 1 shows the specifications of each fixed abrasive polishing sheet using diamond abrasive, alumina abrasive, and silica abrasive.

The polishing head 10 is arranged with its own length direction in a direction orthogonal to the conveyance direction A of the glass substrate W, and the length of the polishing head 10 is conveyed on the conveyance path, or the conveyance direction. The length is set such that all of a plurality of (two in the illustrated example) glass substrates W conveyed in a state of being arranged in a direction perpendicular to each other can be polished at a time.
As shown in FIGS. 1 and 6, two fixed abrasive polishing sheets 23 are affixed to the lower surface 20 a of the polishing plate 20 in parallel in the transport direction of the glass substrate W and spaced apart from each other in parallel. In addition, the polishing plate 20 is provided between the two fixed abrasive polishing sheets 23 and is provided with a liquid supply port 13 for supplying pure water to a portion polished by the fixed abrasive polishing sheet 23. .

As shown in FIGS. 3 and 7, the polishing plate 20 is provided on the main body 11 of the polishing head 10 so as to be movable in the vertical direction with the fixed abrasive polishing sheet 23 facing downward.
As shown in FIG. 7, the main body 11 of the polishing head 10 is provided with a pressing chamber 14 having an opening 14 a on the lower surface, and the upper portion of the polishing plate 20 is accommodated inside the pressing chamber 14. The lower part of the polishing plate 20 protrudes downward from the opening 14a. The polishing platen surface 20a on the lower surface of the polishing plate 20 faces the upper surface of the glass substrate W being conveyed.

  Further, between the main body 11 of the polishing head 10 and the polishing plate 20, there are provided a pressurizing tube 18 and a reaction force tube 19 for pressing the polishing plate 20 against the glass substrate W and adjusting the pressing force. Yes.

The pressurizing tube 18 is expanded by introducing pressurized air (a gas other than air may be used) and presses the polishing plate 20 downward, and between the ceiling wall of the pressing chamber 14 and the upper end wall of the polishing plate 20. Is arranged.
The reaction force tube 19 expands by introducing pressurized air (or a gas other than air) and presses the polishing plate 20 upward against the pressure of the pressure tube 18. It is disposed between the flange 25 projecting left and right and the left and right flanges 15 of the opening 14 a on the main body 11 side of the polishing head 10.
FIG. 7B shows the relationship between the downward force P1 caused by the pressurizing tube 18 and the upward force P2 caused by the reaction tube 19. The pressurizing tube 18 and the reaction force tube 19 are disposed over almost the entire length of the polishing plate 20 in the length direction.

  A pressure adjusting means (not shown) is connected to a pressurized air supply / exhaust pipe (not shown) connected to the pressure tube 18 and the reaction force tube 19. The pressure adjusting means adjusts the pressure balance of the pressurized air introduced into the pressurizing tube 18 and the reaction force tube 19, and the pressure adjusting means, the pressurizing tube 18 and the reaction force tube 19 are used to adjust the glass substrate W. A pressing adjustment mechanism for adjusting the pressing force (that is, polishing pressure) of the polishing plate 20 with respect to is configured.

  In addition, the polishing machine of this embodiment includes at least a motion component in the in-plane direction orthogonal to the conveyance direction of the glass substrate W via the swing shaft 12 protruding from the upper end of the polishing head 10. A drive mechanism (not shown) for orbital movement is provided.

  Next, a method for polishing a film (RGB film) on the surface of the glass substrate W using the polishing machine having the above configuration will be described.

  When the glass substrate W is transported under the polishing head 10 by the transport conveyor 1, as shown in FIG. 7B, pressurized air is introduced into the pressurizing tube 18 and also applied to the reaction force tube 19. The compressed air is introduced, the polishing plate 20 is lowered, and the lower surface of the polishing plate 20 is pressed against the surface (RGB film surface) of the glass substrate W. At this time, by adjusting the pressure balance between the pressurizing tube 18 and the reaction force tube 19, the pressing force of the polishing plate 20 against the glass substrate W can be set to a suitable value.

  At this time, as shown in FIG. 4, the surface of the fixed abrasive polishing sheet 23 and the surface of the glass substrate W are different from conventional ones and are completely in contact with each other. Thus, the film on the surface of the glass substrate W is polished by the fixed abrasive polishing sheet 23.

  In this case, as shown in Table 1, the abrasive grains 27 included in the polishing layer 26 of the fixed abrasive polishing sheet 23 are composed of ultrafine particles having a particle diameter of 10 to 50 nm (preferably 10 to 20 nm), and diamond abrasive grains As shown in FIG. 8, since there are no coarse particles having a particle size of several μm order (3 to 8 μm), only the abnormal protrusion 300 (see FIG. 8) is efficiently polished without damaging the film on the surface of the glass substrate W during polishing. -Can be removed.

  For example, even if the abnormal protrusion 300 is gradually polished from the tip portion and the polishing layer 26 of the fixed abrasive polishing sheet 23 reaches the normal thickness film surface of the glass substrate W, as described above, the abrasive 27 Since the particle size of the film is extremely fine, 10-50 nm, the film surface is only mirror-polished (finish polishing), and there is no possibility of causing a polishing scratch that cannot be used. Thus, it is possible to efficiently polish and remove only the abnormal protrusion 300 without reducing the thickness of the film.

  Furthermore, since silica particles are used as the abrasive grains 27, since the silica particles are ultrafine particles, the abrasive hardness is considerably lower than diamond abrasive grains or alumina abrasive grains (see Table 1). The occurrence of scratches can be prevented more reliably.

  Thus, in the polishing machine of this embodiment, the conventional clearance adjustment pad is eliminated, and the entire polishing is performed by bringing the fixed abrasive polishing sheet 23 and the glass substrate W into contact with each other. Therefore, the polishing reproducibility is high, and The number of members used is small, and the cost can be reduced.

  Further, since the elastic sheet 21 is interposed between the polishing surface plate 20 and the fixed abrasive polishing sheet 23, the pressing force applied to the glass substrate W is dispersed by the cushioning action of the elastic sheet 21, and the glass substrate W Since the entire surface is polished with a uniform polishing pressure, the occurrence of polishing spots can be prevented.

  Further, by supplying pure water from the liquid supply port 13 to the polishing surface during polishing, polishing debris can be eliminated, so that generation of polishing flaws due to polishing debris can be prevented.

After the polishing is finished, as shown in FIG. 7A, the pressurized air from the pressure tube 18 is extracted, the pressurized air is introduced into the reaction tube 19, the polishing plate 20 is raised, and the next glass substrate. Prepare for W loading.
As described above, according to the present polishing machine, removal of abnormal protrusions on the surface of the glass substrate and finish polishing can be performed at the same time, so that it can greatly contribute to improvement of product yield and quality.

Here, in order to confirm the effect of the polishing machine of the present embodiment, the following polishing test was performed. The physical properties of the elastic sheet (urethane sheet) interposed between the polishing surface plate and the fixed abrasive polishing sheet are as follows: density: 0.25 gr / m ³ , compression ratio: 18-20%, elastic modulus: 96%, hardness : 20 to 21 °.

(1) Comparative Example An alumina sheet was used as the fixed abrasive polishing sheet, and abnormal protrusions on the color filter surface were polished by the above-described polishing method. Table 2 shows the polishing conditions and the results of the polishing test.

As shown in Table 2, in the polishing using an alumina sheet, abnormal protrusions can be ground, but a large number of contact scratches due to alumina abrasive grains are generated on the surface of the color filter film. there were. It should be noted that this contact scratch could not be alleviated / eliminated even after finishing polishing.
(2) Examples

  A silica sheet was used as the fixed abrasive polishing sheet, and abnormal protrusions on the color filter surface were polished. Table 3 shows the polishing conditions and the results of the polishing test at that time.

  As shown in Table 3, in the polishing using a silica sheet, abnormal protrusions could be ground to 3 to 5 μm without causing contact scratches due to abrasive grains.

  From the above results, by using silica particles having a particle diameter of 10 to 50 nm as the abrasive grains of the fixed abrasive polishing sheet, it is possible to efficiently polish only the abnormal protrusion 300 without reducing the thickness of the normal thickness film. It was confirmed that it could be removed.

The top view which shows the principal part structure of the manufacturing line of the glass substrate (color filter) equipped with the polisher by embodiment of this invention. The side view which shows the principal part structure of a manufacturing line. Sectional drawing seen from the side of the conveyance direction of the glass substrate which shows the lower part structure of a grinding | polishing plate. The principal part enlarged view which shows a state when pressing a grinding | polishing plate against a glass substrate. Sectional drawing which shows the structure of an abrasive sheet. The figure which looked at the polishing plate from the bottom. It is sectional drawing seen from the side of the conveyance direction of the glass substrate which shows the structure of a grinding | polishing head, (a) shows the state before pressing a polishing plate against a glass substrate, (b) presses a polishing plate against a glass substrate. Indicates the state of the Sectional drawing of the color filter for liquid crystal display devices.

Explanation of symbols

1 Transport route (transport conveyor)
3 Lower surface plate 10 Polishing head 20 Polishing plate 20a Polishing surface plate surface 21 Elastic sheet 23 Polishing sheet (fixed abrasive polishing sheet)
24 Base material 26 Polishing layer 27 Abrasive grain CF Color filter W Glass substrate

Claims (6)

The surface of the glass substrate is moved by moving the polishing plate in-plane with respect to the glass substrate while pressing the polishing plate having a polishing plate attached to the surface of the glass substrate on which the film is formed. In a polishing machine for polishing the film of the film with the polishing sheet,
A polishing machine, wherein a primary particle diameter of abrasive grains contained in a polishing layer of the polishing sheet is 10 to 50 nm. The polishing machine according to claim 1, wherein a primary particle diameter of the abrasive grains is 10 to 20 nm. The polishing machine according to claim 1 or 2, wherein the abrasive grains are silica particles. The polishing machine according to any one of claims 1 to 3, wherein the polishing sheet is attached to a polishing platen surface of the polishing plate via an elastic sheet. The lower surface plate on which the glass substrate is placed is disposed below the conveyance path for conveying the glass substrate along the surface direction,
A polishing head for polishing the upper surface of the glass substrate that has been conveyed is provided above the lower surface plate,
In the main body of this polishing head, with the polishing sheet facing downward, the polishing plate as an upper surface plate is provided movably in the vertical direction,
Between the main body of the polishing head and the polishing plate, a pressing adjustment mechanism for pressing the polishing plate against the glass substrate and adjusting the pressing force is provided,
5. The driving mechanism according to claim 1, further comprising an orbital movement that causes the polishing head to include at least a movement component in an in-plane direction orthogonal to a conveyance direction of the glass substrate. A polishing machine according to crab. The polishing machine according to any one of claims 1 to 5, wherein the glass substrate is a color filter of a display panel, and the film is an RGB colored film.

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