JP2007253294A - Method for dressing polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for dressing a polishing pad, which efficiently dresses the polishing pad with a simple configuration. <P>SOLUTION: The method for dressing the polishing pads 12, 22 stuck on the surface of a polishing plate comprises steps of: blush-cleaning for cleaning the polishing pads by bringing brushes 34 into contact with the polishing pads; and high pressure water cleaning for cleaning the polishing pads by jetting high pressure water 46, 47 on the polishing pads. After the polishing steps have been finished for the required number of times, either one of the blush-cleaning step and the high pressure water cleaning step is carried out. After the polishing steps further have been finished for the required number of times, the other of the blush-cleaning step and the high pressure water cleaning step is carried out. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing pad dressing method for regenerating a polishing pad affixed to a surface of a surface plate of a polishing machine that performs polishing.

  Polishing is performed to finish the surfaces of various substrates such as glass materials, metal materials, semiconductor materials, and ceramic materials into smooth mirror surfaces. In recent years, with the miniaturization and high density of magnetic disks, glass disks having excellent surface smoothness and mechanical strength are frequently used as information recording medium disks. A glass disk for an information recording medium is lapped after lapping the front and back recording surfaces of the glass disk.

  A polishing pad made of polyester felt, porous polyurethane resin, or the like is attached to the surface of a surface plate of a polishing machine used for polishing. If polishing is continued while supplying a polishing liquid in which abrasive grains made of cerium oxide or the like are suspended in water, the polishing pad is clogged with abrasive grains or processing waste generated by polishing glass. Occurs.

  When clogging occurs in the polishing pad, the amount of polishing removal of the glass disk per hour is reduced and the polishing ability is lowered. Therefore, it is necessary to remove clogging in the polishing pad, that is, to perform dressing. Usually, the clogged polishing surface is rubbed with a brush such as nylon (for example, see Patent Document 1) and / or high pressure water is sprayed on the clogged polishing surface (for example, see Patent Document 2). For example, the polishing pad is dressed by sweeping away abrasive grains and work chips clogged on the polishing surface of the polishing pad.

Although dressing with a brush is effective for removing relatively large particles (machining debris) embedded in the surface layer of the polishing pad, it removes relatively small particles (polishing abrasive grains) entering the inner layer of the polishing pad. Is not very effective. Conversely, dressing with high-pressure water is effective in removing relatively small particles (abrasive grains) that have entered the inner layer of the polishing pad, but relatively large particles (processed) embedded in the surface layer of the polishing pad. It is not very effective in removing debris. An apparatus capable of performing both dressing with a brush and dressing with high-pressure water has been proposed (see, for example, Patent Document 3). The effect of the dressing is higher when both the dressing with the brush and the dressing with the high-pressure water are performed at the same time. Alternatively, there is a problem that the dressing apparatus becomes complicated and large.
Japanese Patent Laid-Open No. 7-9326 JP 2001-88009 A Japanese Patent Laid-Open No. 7-9340

  Therefore, a technical problem to be solved by the present invention is to provide a polishing pad dressing method capable of efficiently dressing a polishing pad with a simple configuration.

Means and actions / effects for solving the problem

  In order to solve the above technical problem, according to the present invention, the following dressing method for a polishing pad is provided.

That is, the polishing pad dressing method according to the present invention comprises:
A dressing method for a polishing pad affixed to the surface of a surface plate,
A brush cleaning step for cleaning the polishing pad by bringing the brush into contact with the polishing pad;
A high pressure water cleaning step for cleaning the polishing pad by spraying the high pressure water onto the polishing pad,
After finishing the predetermined number of polishing steps, perform either the brush cleaning step or the high pressure water cleaning step, and after finishing the predetermined number of polishing steps, either the brush cleaning step or the high pressure water cleaning step. It is characterized by performing.

  According to the above method, after a predetermined number of polishing steps, relatively large particles (processing waste) embedded in the surface layer portion of the polishing pad as a result of polishing in the polishing step are removed by dressing with a brush. Then, after a predetermined number of polishing steps, relatively small particles (polishing abrasive grains) that have entered the inner layer of the polishing pad as a result of polishing in the polishing step are removed by dressing with high-pressure water. When performing dressing with a brush on a certain polishing machine, it is possible to perform dressing with high-pressure water on another polishing machine, so that the total time required for the dressing process is shortened and the dressing device is There will be no loss of equipment operation.

  Preferably, the brush cleaning step is performed after the predetermined number of polishing steps are completed, and the high pressure water cleaning step is performed after the predetermined number of polishing steps are completed.

  According to the above method, the relatively large particles (processing waste) embedded in the surface layer portion of the polishing pad are removed by the brush cleaning step, and the high pressure water cleaning step is performed to enter the inner layer portion of the polishing pad. However, it is easy to remove relatively small particles (abrasive grains).

  Hereinafter, an embodiment of a dressing method for the polishing pads 12 and 22 according to the present invention will be described in detail with reference to FIG.

  FIG. 1 is a schematic diagram for explaining an embodiment of a dressing method for polishing pads 12 and 22 according to the present invention. (A) shows the dressing of the polishing pads 12, 22 by the brush carrier 30, and (B) shows the dressing of the polishing pads 12, 22 by the high-pressure water 46, 47.

  The double-side polishing machine 1 to which the dressing method according to the present invention is applied includes a substantially disk-shaped upper surface plate 10 that can rotate around a main shaft 5 that extends in the vertical direction, and a main shaft 5 that extends in the vertical direction. A polishing plate made of cerium oxide or the like disposed above the polishing pads 12 and 22, a substantially disk-shaped lower surface plate 20 that can rotate around the upper surface plate 10, a motor that rotationally drives the upper surface plate 10 and the lower surface plate 20. A cleaning liquid supply pipe for dropping a polishing liquid suspended in water or pure water as a cleaning liquid onto the polishing pads 12 and 22, and an upper surface plate 10 by positioning the upper surface plate 10 at a predetermined position. And a holding mechanism that keeps the distance from the lower surface plate 20 constant.

  On substantially the entire lower surface of the upper surface plate 10 and substantially the entire upper surface of the lower surface plate 20, for example, non-woven fabric such as polyurethane, polyester, polyvinyl alcohol, polyamide, cellulose fiber, felt, foam sheet, etc. Polishing pads 12 and 22 made of a material are attached. Needless to say, the present invention is also applicable to a single-side polishing machine that performs polishing with a substantially disk-shaped lower surface plate with a pressure head interposed therebetween.

  As shown in FIG. 1A, when performing dressing with the brush carrier 30, a plurality of substantially disc-shaped brush carriers 30 are interposed between the polishing pad 12 of the upper surface plate 10 and the polishing pad 22 of the lower surface plate 20. Are disposed in contact with each other. Each brush carrier 30 is configured to be rotatable about an axis that is spaced apart from the main shaft 5 in the radial direction of the surface plate and extends parallel to the main shaft 5. The brush carrier 30 includes a substantially disc-shaped brush base 32 and brushes 34 implanted on the upper and lower surfaces of the brush base 32.

  The brush 34 is made of a material such as nylon, polypropylene, polyester, or polyurethane. The brushes 34 can be arranged evenly over the entire surface of the brush base 32 or can be arranged in a hollow donut shape. In addition, the length of the hair feet of the brush 34 is preferably longer than the length of the hair feet of the polishing pads 12 and 22. The outer peripheral portion of the brush 34 preferably has a long bristle leg and a low elasticity as compared with the central portion. If it does in this way, it has an effect which prevents that a foreign material scatters when scraping out the embedded foreign material, and it can prevent that other places get dirty.

  As shown in FIG. 1B, a high-pressure water injection device 40 that injects high-pressure water 46 and 47 onto the polishing pads 12 and 22 is installed on the double-side polishing machine 1 described above.

  The high-pressure water jet device 40 includes a movable base, an upper arm 42 and a lower arm 43 that are attached to the movable base and extend in the horizontal direction, an arm moving mechanism that moves the arms 42 and 43, and an upper arm 42. An upward spray nozzle 44 attached to the lower arm 43, a downward spray nozzle 45 attached to the lower arm 43, a high-pressure water supply part for producing high-pressure water, and a water supply hose connecting each of the injection nozzles 44, 45 and the high-pressure water supply part And a cover that covers the periphery of each of the injection nozzles 44 and 45 and prevents the high-pressure water 46 and 47 from scattering, and the injection conditions of the high-pressure water 46 and 47 (injection pressure, amount of injection water, injection time, injection timing, etc.) And a control unit that controls the movement conditions of the arms 42 and 43, and the like.

  The movable base is provided with movable means such as wheels on the lower surface thereof so that the movable base can be moved and installed at the installation locations of the plurality of double-side polishing machines 1 described above.

  The upper arm 42 and the lower arm 43 are configured to be rotatable and extendable with respect to the movable base. By the arm moving mechanism, the upper arm 42 and the lower arm 43 perform a rotational motion and a telescopic motion while maintaining a certain distance from the upper surface plate 10 and the lower surface plate 20.

  Each of the injection nozzles 44 is arranged so that the upward injection nozzle 44 faces the polishing pad 12 of the upper surface plate 10 while being spaced apart and the downward injection nozzle 45 is opposed to the polishing pad 22 of the lower surface plate 20 with separation. , 45 are arranged.

  In order to confirm the effect of the dressing method for the polishing pads 12 and 22 according to the present invention, eight dressing machines 1, two dressing devices using the brush carrier 30, and one high-pressure water jet device 40. The following tests were conducted using

  Dressing using the brush carrier 30 was performed on the polishing machine 1 that had finished polishing the magnetic recording glass disk built in the hard disk drive four times. The used brush carrier 30 is a nylon brush 34, the thickness of the brush base 32 is about 20 mm, the thickness of the hair of the brush 34 is about 0.3 mm, and the protruding amount of the hair tip of the brush 34 is About 7.5 mm. Dressing with the brush carrier 30 is performed with pure water at a flow rate of about 1000 ml / min on the surface plate while the brush carrier 30 is sandwiched between the upper and lower surface plates 10 and 20 and a load of about 20 kg / carrier is applied. The upper and lower surface plates 10 and 20 and the brush carrier 30 were rotated while the polishing pad 12 and the polishing pad 12 and 22 were dressed for 3 minutes. In addition, the rotation speed of the upper and lower surface plates 10 and 20 was set to 80 rpm clockwise, and the rotation speed of the brush carrier 30 was set to 60 rpm clockwise.

  By such dressing by the brush carrier 30, relatively large particles (processing waste) embedded in the surface layer portions of the polishing pads 12 and 22 are scraped by the brush 34, and the surfaces of the polishing pads 12 and 22 are cleaned. It was. When the magnetic recording glass disk was polished using the polishing pads 12 and 22 after the dressing, a clean mirror surface was obtained.

  Next, after performing dressing with such a brush carrier 30, dressing with high-pressure water 46, 47 was performed on the polishing machine 1 that finished normal polishing four times. Using the arm moving mechanism, the upper arm 42 and the lower arm 43 are rotated and / or expanded / contracted with respect to the polishing pads 12 and 22 so that the high-pressure water 46 and 47 is uniformly sprayed onto the polishing pads 12 and 22. I was allowed to do. High-pressure water 46 and 47 having an injection pressure of about 7 MPa and a water volume of about 10 liters / minute was sprayed for 1 minute toward the polishing pads 12 and 22 of the upper and lower surface plates 10 and 20 rotating at 60 rpm in a clockwise direction.

  By dressing with such high-pressure water 46, 47, relatively small particles (polishing abrasive grains) that have entered the inner layers of the polishing pads 12, 22 have been removed, and the surfaces of the polishing pads 12, 22 have been cleaned. . When the magnetic recording glass disk was polished using the polishing pads 12 and 22 after the dressing, a clean mirror surface was obtained.

  In the above embodiment, as a preferred example, the brush cleaning step is performed after the four polishing steps are completed, and the high pressure water cleaning step is performed after the four polishing steps are completed. It is preferable to perform a high-pressure water cleaning step after the polishing step is completed, and to perform a brush cleaning step after the four polishing steps are completed. Further, the number of times of polishing before each cleaning step is not limited to the number of times described above, but is appropriately determined by judging the state in which the surfaces of the polishing pads 12 and 22 have deteriorated due to the polishing process.

It is a schematic diagram explaining one Embodiment of the dressing method of the polishing pad which concerns on this invention. (A) shows the dressing of the polishing pad with a brush carrier, and (B) shows the dressing of the polishing pad with high-pressure water.

Explanation of symbols

1: Polishing machine 5: Spindle 10: Upper surface plate 12: Polishing pad 20: Lower surface plate 22: Polishing pad 30: Brush carrier 32: Brush base 34: Brush 40: High pressure water jet device 42: Upper brush 43: Lower brush 44: Upward injection nozzle 45: Downward injection nozzle 46: Upward high pressure water 47: Downward high pressure water

Claims (2)

A dressing method for a polishing pad affixed to the surface of a surface plate,
A brush cleaning step for cleaning the polishing pad by bringing the brush into contact with the polishing pad;
A high pressure water cleaning step for cleaning the polishing pad by spraying the high pressure water onto the polishing pad,
After finishing the predetermined number of polishing steps, perform either the brush cleaning step or the high pressure water cleaning step, and after finishing the predetermined number of polishing steps, either the brush cleaning step or the high pressure water cleaning step. A method of dressing a polishing pad, comprising:   2. The polishing pad dressing method according to claim 1, wherein the brush cleaning step is performed after a predetermined number of polishing steps are completed, and the high pressure water cleaning step is further performed after the predetermined number of polishing steps are completed. .

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