JP2009214271A - Abrading tool for abrading apparatus, and grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that need of repair and process for a polishing material surface is caused due to too small or too large wear amount of an inner diameter of a polishing material, and a glass substrate cannot be polished to a target shape after the glass substrate is polished by a polishing tool having the disc shape polishing material with an inner diameter portion. <P>SOLUTION: In the polishing tool for the polishing apparatus which fixes the disk-shaped polishing material 15d where the inner diameter hole 15c is formed in the center on one face side of a tool retaining disc 15b, and polishes a surface of the polished member that is brought into contact with the polishing material 15d by rotating the tool retaining disc 15b by the polishing apparatus, an inner/outer diameter ratio that is a ratio of an outer diameter to the inner diameter of the inner diameter hole 15c of the disk-shaped polishing material 15d is set to 10% or more and 20% or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a disc-shaped polishing tool having a circular inner diameter hole in a central portion used in a polishing apparatus for polishing the surface of a plate-like workpiece such as a glass plate, and a polishing method using the polishing tool. .

  In manufacturing a liquid crystal display, for example, R, G, and B color filter patterns and a TFT array pattern are formed on a glass substrate by exposure to a photomask substrate. This photomask substrate has a mask formed on the surface of a quartz glass substrate (hereinafter referred to as a glass substrate), and the surface of the glass substrate is polished to a high degree of flatness by polishing.

  In addition, this glass substrate has a rectangular shape, and in its surface polishing process, it has been proposed to apply a bobbin-shaped polishing locus to an Oscar type polishing machine as a chemical mechanical polishing apparatus (Patent Document 1). .

  The Oscar-type polishing machine has a rotary shaft in the vertical direction, a lower surface plate that rotates about the rotation shaft, and swings (reciprocates) in the radial direction with respect to the lower surface plate, and a vertical rotation shaft And an upper surface plate that rotates around the upper surface plate, a glass substrate as a workpiece is held on the lower surface plate, and a polishing tool is attached to the upper surface plate. When the glass substrate has a flat rectangular shape, it is driven synchronously so that the upper surface plate reciprocates four times with one rotation of the lower surface plate, and a rectangular frame-shaped polishing locus (hereinafter referred to as rectangular polishing) on the surface of the glass substrate that is the workpiece. Form a trajectory).

  The polishing tool has an abrasive material that has a function as a rotating grindstone and is formed in a disc shape having an inner diameter hole opened in a circular shape at the center.

  Further, as a method of processing the surface of the glass substrate to a high flatness, a polishing (grinding) amount for obtaining the desired flatness is obtained based on the surface shape of the glass substrate measured in advance, and the obtained polishing amount There is a correction processing method in which the surface is processed into a desired shape.

And as a polishing tool for processing the surface of such a glass substrate with high flatness, a polishing tool provided with a disc-shaped polishing material having an inner diameter hole is used, and the polishing tool is a workpiece. The glass substrate rotates while reciprocating the polishing path from the outer periphery to the center, and is processed while applying a constant pressure to the glass substrate (constant pressure processing), or the polishing tool is lowered by a certain amount (incision processing). In this case, polishing is performed, and an abrasive is interposed between the tool surface, which is the lower surface of the polishing material of the polishing tool, and the glass substrate.
JP 2006-062055 A

  Conventionally, a double-side polishing machine has been used in polishing a glass substrate, and there is an advantage that a plurality of sheets can be processed at a time. However, as the size of glass substrates has increased in size in recent years, the size of the apparatus has become very large, making it difficult to manufacture the polishing apparatus itself. Therefore, an Oscar type polishing machine that requires a relatively small apparatus size is suitable for polishing large glass substrates. Can be said to be suitable.

  In an Oscar type polishing machine, a polishing tool provided with a disc-shaped polishing material having an inner diameter hole is formed on a polishing locus set in advance by rotation of a glass substrate which is a workpiece (member to be polished). The polishing tool and the glass substrate rotate while moving. At that time, the surface of the glass substrate is polished, and at the same time, the tool surface of the polishing tool is worn.

  The amount of polishing of the glass substrate that is the workpiece and the amount of wear on the tool surface of the polishing tool are proportional to the relative speed between the polishing tool and the glass substrate that is the workpiece, the applied pressure of the polishing tool to the workpiece, and the processing time. To do.

  In addition, the relative speed between the polishing tool and the glass substrate that is the workpiece is near the center of the rotating polishing tool, and the rotation speed is close to zero. Therefore, the diameter (inner diameter) of the inner diameter hole of the abrasive constituting the polishing tool is In the case of a polishing tool having a relatively small wear rate (for example, a cast iron polishing tool) without a small hole or an inner diameter hole, the surface of the abrasive material, which is the tool surface of the polishing tool, is an inner peripheral side and an outer peripheral side. Therefore, there is a difference in the amount of wear, and the shape of the tool surface of the polishing tool (the shape of the abrasive) is remarkably deformed. Therefore, the tool shape needs to be corrected, and the production efficiency may be reduced.

  Therefore, if the diameter of the inner diameter hole is increased, the difference between the outer periphery and the inner periphery is reduced, and the deformation of the tool shape of the polishing tool can be reduced. However, the width of the tool surface used for polishing is reduced and polishing can be performed at a time. The area becomes smaller. In particular, in order to shorten the polishing time when polishing the surface of a large glass substrate having a size of, for example, 1220 mm × 1400 mm or larger, the area of the tool surface of the polishing tool should be as large as possible. It is hoped to do.

  By the way, when a material to be polished such as a glass substrate is polished by a polishing tool having an inner diameter hole, a protrusion may be formed on a part of the surface of the material to be polished such as a glass substrate as shown in FIG. It was. FIG. 5 shows a processed surface shape indicated by a solid line obtained by polishing the surface of the glass substrate with a polishing tool, and a shape (hereinafter referred to as a reference shape) interpolated on the assumption that there is no protrusion indicated by a broken line. The x axis indicates the substrate surface direction, and the y axis indicates the substrate thickness direction.

  As a cause of the formation of the protruding portion, when a polishing substrate is swung, for example, to polish the glass substrate, a portion of the surface of the glass substrate where the inner diameter hole of the polishing tool passes is a portion where the inner diameter hole does not pass. As a result, the amount of polishing is reduced, and as a result, the shape of the substrate through which the inner diameter hole passes protrudes as compared with the periphery. The generation of such protrusions becomes more significant as the diameter (inner diameter) of the inner diameter hole of the polishing tool becomes larger, and in particular, the movement width L of the polishing tool shown in FIG. 2 is in a range narrower than the diameter of the inner diameter hole of the polishing tool. The case becomes noticeable.

  When the projection amount (the degree of change from the reference shape of an object to be polished such as a glass substrate) is a value obtained by standardizing the projection amount of the projection portion with the average polishing amount of the glass substrate after processing, the surface of the glass substrate is highly flat It is necessary to make the protrusion degree as small as possible in order to process at the same time. However, in order to simply reduce the protrusion degree, the diameter of the inner diameter hole may be reduced. In this case, however, the tool shape is deformed as described above.

  In addition, when drawing a circular polishing locus on the rotating glass substrate, it is not necessary to synchronize between the rotation of the glass substrate and the reciprocating drive of the tool, so the swing range of the tool is increased, for example, The rotation radius of the glass substrate may be set to a reciprocating swing range. However, when this is applied to a rectangular glass substrate, non-uniform polishing in which a difference in polishing amount occurs between the sides and corners of the substrate. In order to avoid this, it is necessary to perform the polishing process by drawing the above-described rectangular polishing locus.

  The object of the present invention is made in view of such a viewpoint, and can suppress the deformation (uneven wear) of the polishing tool accompanying the polishing process, and the object of the surface of the member to be polished such as a glass substrate to be processed. An object of the present invention is to provide a polishing tool for a polishing apparatus that can be polished into a shape.

  Another object of the present invention is to provide a polishing method capable of polishing the surface of a member to be polished without forming a protrusion with a polishing tool having an inner diameter hole.

  The structure of a polishing tool for a polishing apparatus that realizes the object of the present invention is to fix a disk-shaped abrasive having an inner diameter portion formed at the center to one side of a tool holding disk, and the tool holding disk is In a polishing tool for a polishing apparatus that rotates and polishes the surface of a member to be polished that is in contact with the polishing material, the disk-shaped polishing material is a ratio of the outer diameter of the polishing material to the inner diameter of the inner diameter portion. The diameter ratio is 10% or more and 20% or less.

  A polishing method that realizes the object of the present invention is a polishing method for processing a surface of a rectangular object to be polished flat. The polishing tool for a polishing apparatus described above traces a single polishing locus, or the diameter of an inner diameter hole. The member to be polished is polished while tracing a plurality of polishing trajectories with a narrower movement width.

  Further, in the above polishing method, the single polishing locus is characterized in that at least two opposite sides are curved inward and pointed toward the four corners of the rectangular member to be polished. .

  According to the polishing tool of the present invention, when polishing is performed while reciprocally swinging the polishing tool against the surface of a member to be polished such as a rotating glass substrate, the polishing tool has an overall shape on the surface of the polishing material. Wear in a balanced manner. For this reason, there is almost no need to correct the surface of the abrasive after polishing.

  Further, according to the polishing method of the present invention, the surface of a member to be polished such as a glass substrate can be processed into a target shape without forming a protrusion, and a polishing tool having an inner diameter hole, in particular, can be polished to a single surface. By polishing the member to be polished while tracing the trajectory, it is possible to polish to the target surface shape without forming the protruding portion.

  According to the invention of claim 3, when polishing the four corners of the member to be polished formed in a rectangular shape such as a glass substrate while tracing along the thread winding locus, Protruding portions due to the influence of the inner diameter hole do not occur, and the surface of the large rectangular glass substrate can be polished to the target shape as a whole.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
Embodiment 1
FIG. 1 is a view showing an embodiment of a polishing tool for a polishing apparatus according to the present invention, FIG. 2 is a view showing the relationship between the polishing tool of FIG. 1 and a glass substrate to be polished, and FIG. Embodiment of a grinding | polishing apparatus is shown, (a) is a schematic top view, (b) shows a schematic front view and a control block diagram.

  The polishing apparatus 10 shown in FIG. 3 has a work rotation drive mechanism 12 having a rotary shaft 11 in the vertical direction attached to a base (not shown).

  The work rotation drive mechanism 12 is composed of a drive motor 12a having a variable rotation speed, a speed reducer 12b, a rotary encoder 12c for detecting a rotation angle (angular velocity) of the motor, and the like, and a rotary shaft 11 is attached to the output side of the speed reducer 12b. A horizontal rotary table 13 is attached to the upper end of the rotary shaft 11.

  A work holding means 14 is installed on the horizontal rotary table 13, and the glass substrate 1 as a work is held on the work holding means 14 in a horizontal posture. In the present embodiment, the work holding means 14 uses a viscoelastic material such as polyurethane having a flat plate shape (hereinafter referred to as a backing pad).

  On the other hand, a polishing tool 15 having a rotary shaft 15 a in the vertical direction is disposed above the horizontal rotary table 13, and the polishing tool 15 is driven to rotate by a tool rotation drive mechanism 16. The tool rotation drive mechanism 16 is attached to a tool horizontal movement mechanism 18 via a tool lifting / lowering mechanism 17, and the tool horizontal movement mechanism 18 is supported and guided by a horizontal guide means 19 and can move in the horizontal direction.

  In this embodiment, as shown in FIG. 1, the polishing tool 15 is formed with a bottomed inner diameter hole 15c (inner diameter d1) in the center of a metal tool holding disk 15b fixed to the tip of the rotary shaft 15a. For example, a cast iron abrasive 15d (outer diameter d2) formed in a disk shape is fixed. Further, the polishing tool 15 has a tool holding plate 15b fixed at a right angle to the rotating shaft 15a. The work holding means 14 is not limited to a backing pad, and may be a steel holding table or the like in which a vacuum suction hole is formed. Further, the polishing tool 15 may have a configuration in which the abrasive can be freely swung with respect to the tool holding plate 15b, or a configuration in which the tool holding plate 15b can be freely swung with respect to the rotating shaft 15a.

  The tool rotation drive mechanism 16 makes the rotation speed variable by a tool rotation speed command from the control device 20 based on the control data received from the personal computer 19, and can detect the rotation speed of the polishing tool 15 by, for example, a rotary encoder.

  The tool elevating mechanism 17 can detect the elevating position of the tool 15 by a position sensor (not shown) and outputs a tool elevating command signal from the control device 20 to an actuator such as a pulse motor (not shown). The polishing tool 15 is moved up and down.

  The tool horizontal movement mechanism 18 causes the polishing tool 15 to reciprocate (swing) along the diameter line passing through the rotation center of the horizontal rotary table 13, and the horizontal direction of the polishing tool 15 by a position sensor (not shown). The position can be detected.

  By adjusting the relationship between the reciprocating amount of the tool 15 and the rotational speed of the horizontal rotary table 13, the tool 15 can polish the glass substrate 1 while drawing various polishing trajectories.

  In the present embodiment, the tool 15 is a tool whose inner / outer diameter ratio, which is the ratio between the inner diameter and outer shape of the tool, is 10% or more and 20% or less, for example, an outer diameter of 700 mm and a tool inner diameter of 100 mm.

  In this embodiment, when the polishing tool 15 polishes the rectangular flat glass substrate 1 by tracing the rectangular polishing trajectory tr shown in FIG. 2 (or a plurality of concentric rectangular polishing trajectories may be set). Since the rectangular polishing locus tr is a single polishing locus, the polishing tool 15 reciprocates in synchronization with the rotation of the glass substrate 1 in order to trace the rectangular polishing locus. In this case, by using the tool 15 having the above-described inner / outer diameter ratio, the formation of the protrusion due to the inner diameter hole of the tool 15 is not seen.

  For example, referring to FIG. 2, the tool 15 is used as long as the inner diameter hole 15 c of the polishing tool 15 does not protrude outward from the outer peripheral end of the glass substrate 1.

  In FIG. 2, a large number of rectangular polishing trajectories may actually be set, and one rectangular polishing trajectory tr is typically shown for easy explanation. This rectangular polishing locus tr has a shape in which four sides are curved inward and pointed toward the four corners of the glass substrate 1, and since this rectangular locus has a shape generally resembling a bobbin winding, Call. Since the polishing tool 15 approaches the four corners of the glass substrate 1 in this thread winding locus, the four corner portions of the glass substrate 1 can be polished in the same manner as other portions, and the surface of the glass substrate 1 can be uniformly polished as a whole. Here, when the substrate longitudinal direction from the center of the glass substrate 1 is set to 0 °, an interval L between the 0 ° position of the outermost track and the 0 ° position of the innermost track is referred to as a tool movement width.

  When the polishing tool 15 finishes tracing one rectangular polishing locus tr, for example, the polishing tool 15 is moved from the outer rectangular polishing locus toward the inner rectangular polishing locus by a predetermined amount, and the rectangular polishing locus tr is traced again. Then, the glass substrate is polished, this series of operations is repeated, and finally the tool movement width L is moved to complete the polishing of the glass substrate 1.

  The present invention is not limited to the bobbin winding locus in which four sides of the rectangular locus are curved inward, but may be a bobbin winding locus in which two opposite sides are curved inward and the other two opposite sides are linear. Alternatively, the trajectory may be a straight line with four sides, or a bobbin-shaped trajectory may be combined with a four-sided linear trajectory.

  In the above-described embodiment, the above-described rectangular trajectory is taken as an example of a single polishing trajectory that is a so-called one-stroke trajectory that is a closed trajectory, but the present invention can be drawn as a single polishing trajectory, Any closed locus can be used as long as it can be drawn by controlling the position of the polishing tool 15 in synchronization with the rotation of a member to be polished such as a rotating glass substrate, for example, a star shape, a pentagon or more polygon, The present invention can be applied to trajectories having various shapes such as an ellipse.

  Further, in the present embodiment, when performing the cutting process in which the tool 15 is lowered stepwise from the upper side to the lower side, the cutting timing (timing to lower the tool 15 by one step) is performed every predetermined machining time. However, it may be performed according to the number of rotations of the rotary table 13.

  In the above-described cutting process, the total amount of descent (target cutting amount) of the tool 15 is obtained from the measurement result of the substrate surface shape based on the correction processing amount required to obtain the target shape.

  The outer diameter of the tool was 700 mm, and the glass substrate was polished with each polishing tool having an inner diameter of 200 mm (Comparative Example 1), 100 mm (Example 1), 50 mm (Comparative Example 2), and 0 mm (Comparative Example 3). At this time, the bobbin trajectory (tr) shown in FIG. 2 was used. Spheroidal graphite cast iron was used as the material of the tool.

  The amount of protrusion and the degree of protrusion of the glass substrate after polishing were determined at two locations, the substrate 0 ° direction and the substrate 90 ° direction, from the substrate center. The results are shown in Table 1. FIG. 4 is a graph showing the relationship between the tool inner diameter and the degree of protrusion in the 0 ° direction of the substrate.

  As shown in Table 1, in a polishing tool having the same outer diameter, the degree of protrusion increases as the tool inner diameter increases in both the substrate 0 ° direction and the substrate 90 ° direction, but the recess depth value decreases. When the degree of protrusion is large, it is necessary to polish again to flatten the substrate, and when the depth of the recess is large, tool correction is required as shown below.

  FIG. 6A shows the relationship between the tool inner diameter and the processed tool shape in Example 1 and Comparative Examples 1 to 3, that is, the relationship between the tool radius and the tool shape (μm).

  In FIG. 6A, the tool shape (the shape of the abrasive 15d) on the outer periphery of Comparative Examples 1 to 3 and Example 1 is about 12 μm, and other tools except Comparative Example 1 have a radius of around 150 mm. The tool shape (the shape of the abrasive 15d) has a recess (Example 1: about 29 μm, Comparative Example 2: about 26 μm, Comparative Example 3: about 25 μm), and a substantially similar tool shape (polishing) from the outer periphery to this recess. The shape of the material 15d).

  FIG. 6B shows a straight line passing through the innermost circumference and the outermost circumference of the tool-shaped tool among the depths of the recesses of the first embodiment and the first to third comparative examples in FIG. 6A. The relationship between the tool radius and the depth of the concave shape was shown, and the maximum value is shown in Table 1 as the concave depth value.

  That is, in Example 1 and Comparative Examples 2 and 3, the middle circumference between the outer circumference and the inner circumference of the abrasive 15d is recessed.

  Here, since the tool (abrasive 15d) is an elastic body, it is considered that the concave portion in the middle of the tool is deformed by the applied pressure and becomes flat to some extent. The deformation at this time includes a deformation that flattens the shape of the entire tool (abrasive 15d) (a deformation that eliminates the difference between the inner periphery and the outer periphery of the tool) and a deformation that flattenes the concave portion of the tool inner periphery. Since the tool pressure is a pressure centered on the rotation axis 15a of the rotation center of the tool, the deformation of the tool inner periphery deviating from the rotation axis 15a is unlikely to occur. That is, the concave shape of the middle peripheral portion of the tool (abrasive 15d) is hardly flattened during the polishing process by the applied pressure of the tool.

  6A, the tool shape (the shape of the abrasive 15d) in the inner periphery of Comparative Example 1 (inner diameter radius: 100 mm) is as large as about 34 μm, and the inner periphery of Comparative Example 2 (inner diameter radius: 25 mm). The tool shape (the shape of the abrasive 15d) is about 13 μm, and the tool shape (the shape of the abrasive 15d) at the center of Comparative Example 3 is about 6 μm. Further, the tool shape (the shape of the abrasive 15d) on the inner periphery of Example 1 (inner diameter radius: 50 mm) is about 20 μm.

  That is, as the inner diameter of the tool becomes smaller, the inner diameter of the tool (the inner circumference of the abrasive 15d) tends not to be worn. As shown in Comparative Example 2, the tool has an inner diameter of less than 10% as shown in Comparative Example 2. The amount of wear on the inner circumference (the inner circumference of the abrasive 15d) becomes extremely small. Furthermore, in Comparative Example 3, since the wear on the inner diameter of the tool is further reduced, the tool shape becomes a top-down shape (the entire tool is a convex shape), and polishing using the entire tool becomes impossible.

  Thus, although the protrusion degree of the glass substrate grind | polished using the grinding | polishing tool of the comparative examples 2 and 3 is smaller than the case where the grinding | polishing tool of Example 1 is used, as mentioned above, the tool shape after processing (abrasive material) 15d) is significantly deformed, and the protrusion degree of the glass substrate polished with the polishing tool of Comparative Example 1 is much larger than that of Example 1, and it is difficult to improve the flatness efficiently.

  On the other hand, as in Example 1, when the outer diameter ratio is 10% or more and within 20%, the substrate projecting degree is as small as 5.17% in the substrate 90 ° direction (the projecting degree of Comparative Example 2 is not so different from 4.69%). It does not affect the polishing process with high flatness.

  That is, in a polishing tool having an inner diameter portion with a tool outer diameter of 700 mm and an inner diameter of around 100 mm (tool inner / outer diameter ratio is about 10% to 20%), the degree of protrusion of the glass substrate to be polished is small, and the wear shape of the tool Balanced. Therefore, the glass substrate can be polished with a high degree of flatness, and the polishing surface of the polishing tool is worn in a well-balanced manner, so that almost no modification of the polishing surface is required.

The figure which shows one Example of the polishing tool for polishing apparatuses by this invention. The figure which shows the relationship between the grinding | polishing tool of FIG. 1, and a glass substrate. The polishing apparatus which can implement this invention effectively is shown, (a) is a schematic top view, (b) shows a schematic front view and a control block diagram. The figure which shows the relationship between a tool internal diameter and the protrusion degree of a board | substrate 0 degree direction. The schematic diagram of a board | substrate protrusion part. (A) is a figure which shows the relationship between a tool internal diameter and the tool shape after a process, (b) is a figure which shows the recessed part depth of a tool inner periphery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 12 Work rotation drive mechanism 13 Horizontal rotation table 14 Work holding means 15 Polishing tool 16 Tool rotation drive mechanism 17 Tool raising / lowering mechanism 18 Tool horizontal movement mechanism 19 Horizontal guide means 20 Controller tr Polishing locus

Claims (3)

A disk-shaped abrasive having an inner diameter formed at the center is fixed to one side of the tool holding disk, and the tool holding disk is rotated by a polishing apparatus to polish the surface of the member to be polished that contacts the abrasive. In a polishing tool for a polishing apparatus,
The polishing tool for a polishing apparatus, wherein the disk-shaped abrasive has an inner / outer diameter ratio, which is a ratio of an outer diameter of the abrasive to an inner diameter of the inner diameter portion, of 10% or more and 20% or less.   In a polishing method for processing a surface of a rectangular member to be polished flat, a polishing tool for a polishing apparatus according to claim 1 is made to trace a single polishing locus, or a plurality of the polishing tools are narrower than the diameter of an inner diameter hole. A polishing method comprising polishing a member to be polished while tracing a polishing locus. 3. The polishing method according to claim 2, wherein the single polishing locus has a shape in which at least two opposite sides are curved inward and pointed toward the four corners of the rectangular member to be polished. .