JP2015196224A - Polishing method and retainer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing method which enables the occurrence of polishing unevenness to be suppressed.SOLUTION: The polishing method includes a polishing process in which a polishing object surface of a polishing object W held by a polishing head 14 of a retainer is polished by binging the polishing object surface of the polishing object W into such a state that the polishing object surface is in pressurized contact with an abrasive pad and by rotating the retainer and the abrasive pad while a polishing composition is fed. During the polishing process, the polishing object W held by the polishing head 14 of the retainer is rotated in such a way that a state in which the polishing object surface faces the abrasive pad side is maintained, so that an orientation of the polishing object W is changed.

Description

  According to the present invention, the polishing surface of the object to be polished held by the holding tool is brought into pressure contact with the polishing pad, and the polishing composition is supplied by rotating the holding tool and the polishing pad relatively while supplying the polishing composition. The present invention relates to a polishing method having a polishing step of polishing a polishing surface of an object, and a holder used in the polishing method.

  Conventionally, as a method of polishing an object to be polished, the polishing surface of the object to be polished held by the holder is pressed against the polishing pad, and the holder and the polishing pad are relatively rotated while supplying the polishing composition. A polishing method for polishing a polished surface of an object to be polished is known. This type of polishing method is carried out using a single-side polishing apparatus or a double-side polishing apparatus. For example, Patent Document 1 discloses a polishing method for polishing one side of a semiconductor wafer using a single-side polishing apparatus. Patent Document 2 discloses a polishing method in which a double-side polishing apparatus is used to simultaneously polish both sides of a computer disk substrate having magnetic films on both sides.

  Hereinafter, the configuration of a single-side polishing apparatus and a conventional polishing method using the single-side polishing apparatus will be described with reference to FIG. As shown in FIG. 12A, the single-side polishing apparatus 10 includes a surface plate 11 that rotates on a rotating shaft that extends in the vertical direction, and a polishing pad 12 is attached to the upper surface of the surface plate 11. On the polishing pad 12, a plurality of holders 13 each having a polishing head 14 that rotates on a rotation axis P1 extending in the vertical direction are arranged. As shown in FIG. 12B, a plurality (three) of the objects to be polished W are held on the lower surface of the polishing head 14 in the holder 13 with the polishing surface facing downward. Further, the respective polishing objects W are held so as to be arranged in the circumferential direction around the rotation axis P <b> 1 of the polishing head 14.

  As shown in FIG. 12 (a), the polishing composition 15 is placed on the polishing pad 12 with the polishing object W held on the lower surface of the polishing head 14 of the holder 13 being in pressure contact with the polishing pad 12. While being supplied, the surface plate 11 and the polishing head 14 of the holder 13 are each rotated at a predetermined rotational speed. Thereby, the polishing surface of the polishing object W held by the holder 13 is polished by the polishing pad 12 and the polishing composition 15.

JP 2011-253896 A Japanese Patent Laid-Open No. 7-156061

  By the way, when the conventional polishing method described above is used, polishing unevenness may occur on the polishing surface of the object to be polished. Specifically, as shown in FIG. 12 (b), the rotational axis P1 of the polishing head 14 corresponds to the polishing amount of the part B (the part located outside) on the side far from the rotational axis P1 of the polishing head 14. In some cases, the polishing amount of the portion A on the near side (portion located on the inner side) was reduced.

  The cause of this problem is considered to be in the polishing composition 15 supplied to the polishing surface of the polishing object W. That is, at the time of polishing, since the polishing head 14 rotates about the rotation axis P1, the polishing composition 15 supplied onto the polishing pad 12 is separated from the polishing object W from the outer peripheral side of the polishing head 14. It enters between the polishing pad 12 and flows toward the radially inner side of the polishing head 14. Therefore, in the polishing object W, the portion B located on the radially outer side of the polishing head 14 is polished using the fresh polishing composition 15, and the portion A located on the radially inner side is subjected to the diameter measurement. Polishing is performed using the polishing composition 15 that is used for polishing the portion B located on the outer side in the direction and in which abrasive grains and the like are consumed. Thus, it is considered that the difference in the degree of wear of the polishing composition 15 used for polishing each part of the polishing object W is one factor that makes the polishing amount different for each part. The above problem of uneven polishing occurs not only in a polishing method using a single-side polishing apparatus but also in a polishing method using a double-side polishing apparatus.

  This invention is made | formed in view of such a situation, The objective is to provide the grinding | polishing method and holder which can suppress generation | occurrence | production of grinding | polishing nonuniformity.

  In the polishing method for achieving the above object, the holding tool and the polishing pad are supplied while supplying the polishing composition in a state where the polishing surface of the object to be polished held by the holding tool is pressed against the polishing pad. Is a polishing method having a polishing step of polishing the polishing surface of the object to be polished, the polishing object held by the holder during the polishing step, the polishing surface of the polishing object Is rotated so as to maintain a state of facing the polishing pad, and the direction of the object to be polished is changed.

  In the polishing method, in the polishing step, the operation of polishing the polishing surface of the object to be polished is stopped, the direction of the polishing object is changed, and then the operation of polishing the polishing surface of the object to be polished is performed. It is preferable to resume.

In the polishing method, it is preferable that a plurality of objects to be polished are simultaneously held by the holder.
The polishing method is used for polishing a polishing object having a curved surface, and the polishing pad is deformed into a shape following the polishing surface having a curved surface by pressing the polishing object against the polishing pad. Polishing is preferred.

  The polishing method is used for polishing a polishing object having a plurality of surfaces, and the polishing pad is pressed into the polishing pad so that the polishing pad is shaped to follow the polishing surface including a plurality of surfaces. It is preferable to polish while deforming.

  In the polishing method, it is preferable that the polishing step is performed in a state where a spacer is disposed between the holder and the object to be polished and the polishing surface of the object to be polished protrudes toward the polishing pad.

  The holding tool for achieving the above object includes the holding tool and the polishing pad while supplying the polishing composition in a state where the polishing surface of the object to be polished held by the holding tool is in pressure contact with the polishing pad. Is a holder used in a polishing method for polishing the polishing surface of the polishing object by relatively rotating the polishing object, the polishing head holding the polishing object, and the polishing object held by the polishing head A rotating mechanism that rotates the object so that the polishing surface is maintained facing the polishing pad, and changes the direction of the object to be polished.

In the holder, it is preferable that the rotation mechanism includes a turntable on which the polishing object is fixed.
The holder preferably includes a spacer that is disposed between the turntable and the polishing object and protrudes the polishing surface of the polishing object toward the polishing pad.

In the holder, the turntable is preferably provided so as to protrude from the polishing head toward the polishing pad.
In the holder, the polishing head is preferably configured to be capable of holding a plurality of the polishing objects.

  According to the polishing method of the said structure, the direction of the grinding | polishing target object hold | maintained at the holder is changed during a grinding | polishing process. Moreover, according to the holder of the said structure, the direction of the grinding | polishing target object hold | maintained at the holder can be changed in a grinding | polishing process. Thus, during the polishing process, a specific portion of the polishing surface of the object to be polished is located at a position where the amount of polishing is relatively increased by supplying a fresh polishing composition (outside in the radial direction of the polishing head). It is suppressed to continue. Similarly, it is possible to prevent the worn polishing composition from being supplied and continue to be located at a position where the polishing amount becomes relatively small (in the radial direction of the polishing head). Therefore, the occurrence of uneven polishing such as an increase in the amount of polishing at a specific portion on the polishing surface of the object to be polished or a decrease in the amount of polishing is suppressed.

  According to the polishing method and the holder of the present invention, the occurrence of uneven polishing can be suppressed.

(A)-(c) is explanatory drawing of the grinding | polishing surface of a grinding | polishing target object. The side view and partial sectional view of a holder. Sectional drawing which shows the state which made the grinding | polishing target object press-contact with a polishing pad. (A)-(d) is a figure which shows direction of the grinding | polishing target object in a grinding | polishing process. Explanatory drawing of a holder provided with a rotation mechanism. Explanatory drawing of a holder provided with a rotation mechanism. Explanatory drawing of a holder and a spacer. Explanatory drawing of a holder provided with a rotation mechanism, and a spacer. Explanatory drawing of a holder provided with a rotation mechanism. (A)-(c) is explanatory drawing of the grinding | polishing surface of a grinding | polishing target object. (A), (b) is explanatory drawing of an Example. (A) is explanatory drawing of a grinding | polishing method and a single-side polish apparatus, (b) is a bottom view of a holder.

Hereinafter, an embodiment of the present invention will be described.
First, the polishing object W to be polished by the polishing method of this embodiment will be described.
As the polishing object W, a polishing object made of metal, synthetic resin, ceramic, or a composite product thereof can be used. Examples of the metal include magnesium, aluminum, titanium, iron, nickel, cobalt, copper, zinc, manganese, and alloys containing at least one of them as a main component. Examples of the synthetic resin include thermosetting resins such as phenol resin, epoxy resin, urethane resin, and polyimide, and thermoplastic resins such as polyethylene, polypropylene, and acrylic resin. Examples of the ceramic include ceramics, glass, fine ceramics, oxides such as silicon, aluminum, zirconium, calcium, and barium, carbides, nitrides, and borides.

The outer shape of the polishing object W is not particularly limited, and may be any shape such as a polygonal shape such as a triangle or a quadrangle, a circular shape, an elliptical shape, or an annular shape.
Further, the polishing object W includes a polishing surface on which polishing is performed as one surface. The shape of the polished surface is not particularly limited. Specifically, as shown in FIG. 1 (a), it may be a flat polishing surface W1 composed of one plane. Further, as shown in FIG. 1B, a part or the whole may be a polished surface W2 having a curved surface shape. In this case, the polished surface W2 may have a curved shape that protrudes outward, a curved shape that protrudes inward, or a combination thereof. Moreover, as shown in FIG.1 (c), the grinding | polishing surface W3 which consists of several surface W3a-W3c may be sufficient. In this case, the polishing surface W3 may have a polyhedral shape that is convex toward the outside, a polyhedral shape that is convex toward the inside, or a combination of these. Further, one or a plurality of surfaces constituting the polyhedral polishing surface W3 may be curved. Note that the number of surfaces constituting the polishing surface W3 may be two or more.

Next, a polishing apparatus used for the polishing method of this embodiment will be described.
A conventional single-side polishing apparatus 10 as shown in FIGS. 12A and 12B can be used for the polishing method of this embodiment. The single-side polishing apparatus 10 includes a surface plate 11 that rotates on a rotating shaft that extends in the vertical direction. The surface plate 11 is connected to a motor (not shown) and rotates when the motor is driven.

  A polishing pad 12 is affixed to the upper surface of the surface plate 11. As the polishing pad 12, an optimum one for polishing the polishing surface of the polishing object W can be arbitrarily used depending on the material of the polishing object W, the shape of the polishing surface of the polishing object W, and the like. The surface shape of the polishing pad 12 is preferably a shape that makes the contact uniform with respect to the entire polishing surface of the object to be polished W, and is appropriately combined with thickness, hardness, etc. in order to provide such a function. Is set.

  Specific examples of the material of the polishing pad 12 include, for example, a woven fabric, a nonwoven fabric, a resin processed product of a nonwoven fabric, a synthetic leather, a synthetic resin foam, and a composite product thereof. Moreover, the polishing pad 12 which consists only of 1 type in the said specific example may be sufficient, and the polishing pad 12 which combines multiple types may be sufficient.

  The hardness of the polishing pad 12 is not particularly limited, but when the polishing surface of the object to be polished W is a shape other than a planar shape, for example, a curved surface shape or a multi-surface shape including a plurality of surfaces, the polishing pad 12 is used. The hardness is preferably a Shore A hardness of 5 or more. The Shore A hardness of 5 or more means that the polishing pad 12 as a specimen whose hardness is measured is placed at room temperature for 60 minutes or more in a dry state with a humidity of 20 to 60%, and the hardness of the polishing pad 12 thereafter is determined. It is measured with a rubber hardness meter (A type) in accordance with JIS K6253 and the value is 5 or more.

  In the single-side polishing apparatus 10 shown in FIG. 12A, a plurality of holders 13 each including a polishing head 14 that rotates on a rotation axis P <b> 1 extending in the vertical direction are arranged above the polishing pad 12. The polishing head 14 is connected to a motor (not shown), and rotates when the motor is driven.

  As shown in FIG. 12B, a plurality of objects to be polished W are held on the lower surface side of the polishing head 14 with the polishing surface facing downward (outside). Although not shown in the figure, a lower surface of the polishing head 14 is provided with a concave portion into which the object to be polished W can be fitted, a holding part configured by a mechanism for vacuum-adsorbing the object to be polished W, and the like. Thus, the polishing object W is held by such a holding portion. Further, on the lower surface of the polishing head 14, each polishing object W is held so as to be aligned in the circumferential direction around the rotation axis P <b> 1 of the polishing head 14.

  Next, the polishing method of this embodiment will be described. Here, a description will be given of a case where the polishing object W having the polishing surface shown in FIG. 1B, specifically, a polishing object W having an outer shape of a square shape and a curved polishing surface W2 is polished. To do.

  As shown in FIGS. 2 and 12B, the three objects W are held on the lower surface of the polishing head 14 of the holder 13 so that the polishing surface W2 faces downward. Then, the holder 13 is lowered toward the polishing pad 12, and the polishing surface W <b> 2 of the object to be polished W held on the lower surface of the polishing head 14 is pressed against the polishing pad 12 to be in pressure contact therewith.

  At this time, as shown in FIG. 3, the polishing pad 12 is deformed into a shape following the polishing surface W2 by pressing the polishing surface W2 having a curved shape. Then, the entire polishing surface W2 is in contact with the polishing pad 12. In other words, the holder 13 is lowered to apply a load (polishing load) to a position where the polishing pad 12 is deformed into a shape following the polishing surface W2 and is in contact with the entire polishing surface W2. 2 and 3, the illustration of the surface plate 11 is omitted.

  Next, as shown in FIG. 12A, while supplying the polishing composition 15 onto the polishing pad 12, the surface plate 11 and the polishing head 14 of the holder 13 are each rotated at a predetermined number of rotations. Thereby, the polishing pad 12 affixed on the surface plate 11 and the polishing object W held by the polishing head 14 of the holder 13 are relatively rotated in a pressure contact state, so that the polishing surface of the polishing object W is polished. W2 is polished by the polishing pad 12 and the polishing composition 15 (polishing step).

  As the polishing composition 15, a known polishing composition, specifically, a processing liquid such as a polishing liquid, lapping liquid or cutting liquid mainly containing abrasive grains and water can be used. Examples of the abrasive grains include alumina, silica, ceria, diamond, and silicon carbide. Only one kind of the above-mentioned abrasive grains may be contained, or plural kinds may be contained. In addition, the polishing composition may contain other components such as a surfactant, a polymer material, a pH adjuster, a scattering inhibitor, a thickener, and a redox agent.

Various conditions in the polishing step are not particularly limited, and can be set as appropriate according to the material and shape of the polishing object W. For example, the flow rate of the polishing composition 15 supplied onto the polishing pad 12 is preferably 10 ml / min or more. The rotation speed of the polishing head 14 of the surface plate 11 and the holder 13 is preferably such that the linear velocity on the polishing surface of the object to be polished W is in the range of 10 m / min to 300 m / min. Further, the polishing load, in per unit area of the polishing surface of the polishing object W, it is preferable that ^{0.05kg / cm 2 ~10kg / cm 2} .

  Further, in the polishing method of the present embodiment, an operation of rotating the polishing object W and the polishing head 14 relative to each other while supplying the polishing composition 15 after a predetermined time has elapsed during the polishing process. (Polishing operation) is temporarily stopped, and an operation of changing the direction of the polishing object W held by the polishing head 14 of the holder 13 is performed.

  Specifically, as shown in FIGS. 4A and 4B, an axis P2 parallel to the rotation axis P1 of the holder 13 is set so that the state where the polishing surface W2 faces the polishing pad 12 side is maintained. Each polishing object W is rotated 90 degrees clockwise around the center. That is, the direction of each polishing object W is changed from the holding state shown in FIG. 4A to the holding state shown in FIG. In FIG. 4, in order to facilitate understanding, a mark (star) is attached to a portion of the polishing surface of the polishing object W that was initially located on the rotation axis P <b> 1 side of the holder 13. Yes. The operation of changing the direction of the polishing object W is performed by removing the polishing object W from the polishing head 14 of the holder 13 and holding it again on the polishing head 14.

  After the direction of the polishing object W is changed, the polishing operation for the predetermined time is performed in the holding state shown in FIG. Thereafter, in the same manner, the direction of the polishing object W is changed from the holding state shown in FIG. 4B to the holding state shown in FIG. 4C, and the predetermined state is changed in the holding state shown in FIG. Perform time polishing operation. Thereafter, the direction of the polishing object W is changed from the holding state shown in FIG. 4C to the holding state shown in FIG. 4D, and the polishing for the predetermined time is performed in the holding state shown in FIG. Perform the operation. Therefore, in this embodiment, the polishing object W is polished in each of four holding states in which the direction of the polishing object W is changed by 90 degrees.

Next, the operation of this embodiment will be described.
As shown in FIG. 4, in the polishing method of this embodiment, the direction of the polishing object W held by the polishing head 14 of the holder 13 is changed during the polishing process. The polishing operation is performed in each holding state in which the direction of the polishing object W is varied. Therefore, during the polishing process, a specific portion of the polishing surface of the object to be polished W is located at a position where the amount of polishing is relatively increased when the fresh polishing composition 15 is supplied (outside in the radial direction of the polishing head 14). It will not continue to be located. Similarly, the worn polishing composition 15 is not supplied and does not continue to be located at a position where the polishing amount becomes relatively small (inside in the radial direction of the polishing head 14). As a result, the occurrence of uneven polishing such as an increase in the amount of polishing at a specific portion of the polishing surface of the object to be polished W or a decrease in the amount of polishing is suppressed.

Next, the effect of this embodiment will be described.
(1) The polishing method is performed with the holding tool 13 and the polishing pad 12 being supplied while the polishing composition 15 is being supplied with the polishing surface of the polishing object W held by the holding tool 13 being in pressure contact with the polishing pad 12. A polishing step of polishing the polishing surface of the object to be polished W by rotating is provided. During the polishing process, the polishing object W held by the holder 13 is rotated so that the state in which the polishing surface W2 faces the polishing pad 12 is maintained, and the direction of the polishing object W is changed. .

According to the above configuration, the occurrence of uneven polishing such as an increase in the amount of polishing at a specific portion on the polishing surface of the object to be polished W or a decrease in the amount of polishing is suppressed.
(2) Each position on the polishing surface of the object to be polished W has a position where the polishing amount is relatively large (outside in the radial direction of the polishing head 14) and a position where the polishing amount is relatively small (the diameter of the polishing head 14). The direction of the polishing object W is changed by rotating the inner side of the direction) and the intermediate position thereof. In FIG. 4, taking as an example a site where the object to be polished W is marked, the position shown in FIG. 4A is a position where polishing is relatively difficult, and the position shown in FIG. The positions shown in FIGS. 4B and 4D are intermediate positions.

  According to the above configuration, when the object to be polished W is rotated 180 degrees, the direction is simply changed so that the position where the polishing amount becomes relatively small and the position where the polishing amount becomes relatively large are switched. In comparison, the entire polished surface is easily polished uniformly. As a result, the occurrence of uneven polishing is more effectively suppressed.

  (3) In the polishing step, after the operation of polishing the polishing surface of the polishing object W is stopped and the direction of the polishing object W is changed, the operation of polishing the polishing surface of the polishing object W is resumed. I have to.

According to the above configuration, the existing single-side polishing apparatus 10 can be used as it is.
(4) The polishing object W is a polishing object having a curved polishing surface W2, and the polishing pad 12 is pressed to the polishing pad 12 so as to follow the curved polishing surface W2. Polishing while deforming.

  In this case, the contact surface of the polishing pad 12 with respect to the polishing surface W2 becomes large, and the polishing pad 12 strongly adheres to the polishing surface W2. Therefore, during the polishing process, the polishing composition 15 that has entered between the polishing object W and the polishing pad 12 becomes difficult to flow between the polishing object W and the polishing pad 12, and the diameter of the polishing head 14 is reduced. It becomes difficult to be supplied inward. As a result, with respect to the polishing amount at the portion B (the outer side in the radial direction of the polishing head 14) on the side farther from the rotation axis P1 of the polishing head 14, the portion A (on the polishing head 14) near the rotation axis P1. The problem that the amount of polishing on the inner side in the radial direction is reduced is particularly noticeable (see FIG. 12B).

  Therefore, the effect of suppressing polishing unevenness by the polishing method of the present embodiment is particularly great when polishing is performed while deforming the polishing pad 12 into a shape that follows the polishing surface W2. The polishing object W is a polishing object W having a polishing surface W3 composed of a plurality of surfaces, and the polishing object W is pressed against the polishing pad 12 and polished into a shape following the polishing surface W3 composed of a plurality of surfaces. The same effect can be obtained when the pad 12 is polished while being deformed.

In addition, this embodiment can also be changed and embodied as follows.
-The number of the grinding | polishing objects W hold | maintained at each holder 13 is not specifically limited, Two or less may be sufficient and four or more may be sufficient. Further, the number of polishing objects W held for each holding tool 13 may be different.

  In the above embodiment, the holder 13 is rotated by driving the motor, but the method of rotating the holder 13 is not limited to this. For example, the holder 13 may be disposed on the polishing pad 12 and the polishing pad 12 may be rotated so that the polishing head 14 is allowed to rotate. In this case, the polishing head 14 of the holder 13 rotates (spins) as the polishing pad 12 rotates.

  In the above embodiment, both the holder 13 and the polishing pad 12 are rotated in the polishing step, but any structure may be used as long as the holder 13 and the polishing pad 12 are relatively rotated. That is, only the holding tool 13 may be rotated with the polishing pad 12 stopped, or only the polishing pad 12 may be rotated with the holding tool 13 stopped.

  Even when only the polishing pad 12 is rotated in a state where the holder 13 is stopped, there arises a problem of uneven polishing of the polishing object W due to a difference in the degree of wear of the polishing composition 15. That is, when only the polishing pad 12 is rotated, the polishing composition 15 supplied onto the polishing pad 12 is interposed between the polishing object W held by the holder 13 and the polishing pad 12. It flows in an arc shape along the rotation direction.

  Here, in the example shown in FIG. 12B, it is assumed that the polishing composition 15 flows in an arc shape from the upper side to the lower side of the drawing. At this time, the portion B of the polishing object W located on the upper side is polished using the fresh polishing composition 15, and the portion A is used for polishing the portion B and the abrasive grains are consumed. Polishing using the polished polishing composition 15 is performed.

  On the contrary, it is assumed that the polishing composition 15 flows in an arc shape from the lower side to the upper side of the drawing. At this time, the part A of the polishing object W located on the upper side is polished using the fresh polishing composition 15, and the part B is used for polishing the part A and the abrasive grains are consumed. Polishing using the polished polishing composition 15 is performed.

  Thus, even when only the polishing pad 12 is rotated in a state where the holder 13 is stopped, a difference occurs in the degree of consumption of the polishing composition 15 used for polishing each part of the polishing object W. . Due to this, polishing unevenness occurs in the polishing object W. The occurrence of unevenness of polishing caused when only the polishing pad 12 is rotated can be suppressed by performing an operation of changing the direction of the polishing object W during the polishing process.

  In the above embodiment, in the polishing process, as the operation of changing the direction of the polishing object W, the operation of changing the angle of the polishing object W by 90 degrees has been performed three times in total, but the polishing object in one operation The change angle of the direction of the object W and the number of operations are not limited to this. For example, the operation of changing the angle of the polishing object W by 120 degrees may be performed twice, or the operation of changing the angle of the polishing object W by 180 degrees may be performed once.

  The change angle S of the direction of the polishing object W and the number of operations T are preferably in a relationship satisfying “S (T + 1) = 360”. In this case, the occurrence of uneven polishing can be more effectively suppressed. Further, the change angle of the direction of the polishing object W may be varied for each operation of changing the direction of the polishing object W.

  In the above embodiment, the polishing object W is pressed against the polishing pad 12 to perform polishing while deforming the polishing pad 12 into a shape following the polishing surface. However, the polishing object is not deformed to the extent that the polishing pad 12 is not deformed. Polishing may be performed with W being in pressure contact with the polishing pad 12. For example, such a polishing method is suitable when the polishing surface of the object to be polished W is a flat polishing surface W1 as shown in FIG.

  In the above-described embodiment, the operation of changing the direction of the polishing object W is performed by removing the polishing object W from the polishing head 14 of the holder 13 and changing the direction of the polishing object W and holding it again. You may perform operation which changes direction of the grinding | polishing target object W with a method. For example, as shown in FIGS. 5 and 6, the orientation of the polishing object W is changed by operating the rotation mechanism using the holder 13 having the rotation mechanism that changes the direction of the polishing object W. May be.

  In the example shown in FIG. 5, an insertion hole 21 that penetrates up and down with respect to the polishing head 14 of the holder 13 is formed, and a circular shape centering on the opening of the insertion hole 21 with respect to the lower surface of the polishing head 14. The receiving recess 22 is formed. A rotation shaft 23 is inserted through the insertion hole 21. A disc-shaped rotary table 24 accommodated in the accommodating recess 22 is fixed to the lower end portion of the rotating shaft 23 protruding into the accommodating recess 22, and the upper end of the rotating shaft 23 protruding toward the upper surface side of the polishing head 14. An operation member 25 is fixed to the part. In the case of the above configuration, the rotation shaft 23, the turntable 24, and the operation member 25 constitute a rotation mechanism.

  In the above configuration, the polishing object W is held on the lower surface side of the turntable 24. Then, when changing the direction of the polishing object W, the operator turns the operation member 25. As a result, the rotating table 24 and the polishing object W held on the rotating table 24 rotate integrally through the rotating shaft 23, and the direction of the polishing object W is changed. According to the above configuration, when changing the direction of the polishing object W, it is not necessary to remove the polishing object W from the polishing head 14 of the holder 13, and the operation of changing the direction of the polishing object W is easily performed. be able to.

  In the example shown in FIG. 6, a circular accommodating recess 22 is formed on the lower surface of the polishing head 14, and a disc-shaped turntable 24 is accommodated in the accommodating recess 22. A rotating shaft of a motor 26 attached in the polishing head 14 is fixed to the turntable 24. The holder 13 is provided with a controller (not shown) that controls the rotation of the motor 26. In the case of the above configuration, the rotating base 24, the motor 26, and the control unit constitute a rotating mechanism.

  In the above configuration, the polishing object W is held on the lower surface side of the turntable 24. Then, when changing the direction of the polishing object W, the control unit rotates the motor 26. As a result, the rotating table 24 and the polishing object W held on the rotating table 24 rotate, and the direction of the polishing object W is changed.

  According to the above configuration, when changing the direction of the polishing object W, it is possible to change the direction of the polishing object W while performing a polishing operation. Therefore, it is not necessary to temporarily stop the polishing operation, and the time required for the polishing process can be shortened.

  As shown in FIG. 7, the spacer 30 is disposed between the polishing head 14 of the holder 13 and the polishing object W, that is, the polishing object 14 is held by the polishing head 14 via the spacer 30. As an example, a polishing operation may be performed. In this case, the presence of the spacer 30 causes the polishing object W to protrude greatly toward the polishing pad 12 side. Therefore, when polishing the polishing surface W3 composed of a plurality of surfaces and the polishing surface W2 having a curved surface (see FIG. 1), even if the thickness of the polishing object W is thin, Thus, it becomes easy to press the polishing object W, and it becomes easy to deform the polishing pad 12 into a shape following the polishing surface.

  The same applies to the case where the holder 13 having a rotating mechanism is used, and the polishing operation may be performed with the spacer 30 disposed between the rotating table 24 and the object to be polished W as shown in FIG. . In addition, as shown in FIG. 9, the same effect can be obtained by using the holder 13 attached to the position where the turntable 24 protrudes from the lower surface of the polishing head 14 instead of using the spacer 30. .

  In the double-side polishing method for polishing both surfaces of the polishing object W using a double-side polishing apparatus, an operation of changing the direction of the polishing object W during the polishing process may be performed as in the above embodiment.

  In this case, as the polishing object W, for example, a polishing object having a polishing surface on both sides as shown in FIG. 10 is used. FIG. 10A shows a polishing object W having a flat polishing surface W1 composed of one plane on both upper and lower surfaces. FIG. 10B shows a polishing object W having a polishing surface W2 having a curved surface partly or entirely on both upper and lower surfaces. FIG. 10C shows a polishing object W having a polishing surface W3 composed of a plurality of surfaces W3a to W3c on both upper and lower surfaces. In the example shown in FIG. 10, the upper and lower surfaces of the polishing object W have the same shape, but the shapes of the upper and lower surfaces may be different from each other.

  Moreover, as a double-side polishing apparatus, a well-known double-side polishing apparatus as disclosed in Patent Document 2 can be used. The double-side polishing apparatus includes a pair of polishing pads that are arranged to face each other in the vertical direction, and a holder that holds the object to be polished W between the polishing pads. The holding tool is, for example, a plate-like member having a holding hole having a shape corresponding to the outer shape of the polishing object W. The holding object W is inserted into the holding hole, and the inner peripheral surface of the holding hole and the polishing object W are inserted. By fitting the side surface Ws (see FIG. 10), the both polished surfaces of the object to be polished W are held in a state of protruding upward and downward.

  In the double-side polishing method, both the polishing surfaces of the polishing object W held by the holding tool are brought into pressure contact with the upper and lower polishing pads, and the holding tool and each polishing pad are relative to each other while supplying the polishing composition. A polishing step of polishing the polishing surface by rotating is performed. In the middle of this polishing process, the polishing object W is removed from the holding hole of the holder, and the polishing object W is inserted into the holding hole while changing the direction of the polishing object W, for example, as shown in FIG. The object to be polished W is held again on the holder. Then, the polishing operation is performed again. As described above, in the double-side polishing method, when an operation for changing the direction of the polishing object W is performed during the polishing process, occurrence of polishing unevenness occurs on both polishing surfaces of the polishing object W in the same manner as in the above embodiment. Can be suppressed.

Next, the present invention will be described more specifically with reference to examples and comparative examples.
(Example)
Using the single-side polishing apparatus shown in FIG. 12 (a), with the polishing surface of the object to be polished held by the holder being in pressure contact with the polishing pad, the holding composition and the polishing pad ( The polishing surface of the polishing object was polished by rotating the surface plate. Specific polishing conditions are as shown in Table 1 below.

In addition, as a grinding | polishing target object, the flat glass plate (length 56mm x width 60mm x thickness 0.86mm) which has a curved grinding | polishing surface as shown in FIG.1 (b) was used. The holding state of the object to be polished with respect to the holder is as shown in FIG. Further, the polishing object is pressed against the polishing pad with a polishing load that deforms the polishing pad into a shape that follows the polishing surface.

  When 6 minutes have elapsed from the start of the polishing operation, the rotation of the surface plate and the holder is stopped, the polishing object held by the holder is rotated 180 degrees, and the holding state shown in FIG. The direction of the polishing object was changed to the holding state shown in (b). Then, the polishing operation was resumed, and after another 6 minutes, the polishing operation was terminated.

  Then, the surface roughness of each part WA, WB, WC of the polishing surface of the polishing object shown in FIG. 11 was measured. The portion WA is a curved edge portion of the object to be polished W, and is located on the radially inner side of the holder during the first polishing operation, and is located on the radially outer side of the holder during the second polishing operation. It is a part. The part WB is a curved edge portion of the object to be polished W, and is located on the radially outer side of the holder during the first polishing operation, and is located on the radially inner side of the holder during the second polishing operation. It is a part. The portion WC is a curved central portion of the object to be polished W, and is a portion located at the center in the radial direction during the first polishing operation and the second polishing operation.

  Table 2 shows the measurement results of the surface roughness of each part. For reference, Table 2 also shows the surface roughness of each part before polishing. The surface roughness was measured using a surface roughness measuring device SURFCOM 1500DX (manufactured by Tokyo Seimitsu Co., Ltd., measurement conditions: Standard: JIS'94 / Filter Cut Off: 250 μm / Measurement Length: 1 mm).

(Comparative example)
The same polishing object as in the example was used, and the polishing operation was performed under the same polishing conditions as in the example. However, in the comparative example, the polishing operation was terminated when the polishing was performed for 10 minutes in the holding state illustrated in FIG. 11A without performing the operation of changing the direction of the object to be polished. Thereafter, the surface roughness of each part WA, WB, WC on the polished surface of the object to be polished was measured in the same manner as in the example. The results are shown in Table 2.

As shown in Table 2, in the comparative example in which the operation for changing the direction of the object to be polished is not performed, the portion WA (the portion of the holder) is compared with the portion WB (the portion positioned on the outer side in the radial direction of the holder). Polishing of the portion located on the inner side in the radial direction) did not proceed, and uneven polishing occurred between the portion WA and the portion WB. On the other hand, in the embodiment in which the operation of changing the direction of the polishing object is performed, the surface roughness of the part WA and the part WB is almost the same, and polishing unevenness occurs between the part WA and the part WB. Not.

  W: polishing object, W1 to W3: polishing surface, 10: single-side polishing apparatus, 11: surface plate, 12: polishing pad, 13: holder, 14 ... polishing head, 15 ... polishing composition, 23: rotating shaft , 24 ... rotary table, 25 ... operating member, 26 ... motor, 30 ... spacer.

Claims (11)

With the polishing surface of the polishing object held by the holder held in pressure contact with the polishing pad, the polishing object is rotated by relatively rotating the holding tool and the polishing pad while supplying the polishing composition. A polishing method comprising a polishing step of polishing the polishing surface of
During the polishing step, the polishing object held by the holder is rotated so that the state in which the polishing surface faces the polishing pad is maintained to change the direction of the polishing object. A polishing method characterized by the above. In the polishing step,
The operation of polishing the polishing surface of the object to be polished is resumed after stopping the operation of polishing the polishing surface of the object to be polished and changing the direction of the object to be polished. The polishing method according to 1.   The polishing method according to claim 1, wherein a plurality of objects to be polished are simultaneously held by the holder. Used for polishing objects to be polished with a curved polishing surface,
4. The polishing object according to claim 1, wherein the polishing object is pressed against the polishing pad and polished while deforming the polishing pad into a shape following a curved polishing surface. Polishing method. Used for polishing a polishing object having a plurality of polishing surfaces,
The polishing object is pressed against the polishing pad and polished while deforming the polishing pad into a shape following a polishing surface composed of a plurality of surfaces. Polishing method.   The spacer is disposed between the holder and the object to be polished, and the polishing step is performed with the polishing surface of the object to be polished protruding toward the polishing pad. The polishing method according to claim 5. With the polishing surface of the polishing object held by the holder held in pressure contact with the polishing pad, the polishing object is rotated by relatively rotating the holding tool and the polishing pad while supplying the polishing composition. A holding tool used in a polishing method for polishing the polishing surface of
A polishing head for holding the polishing object;
A rotation mechanism for rotating the polishing object held by the polishing head so that a state in which the polishing surface faces the polishing pad is maintained, and changing a direction of the polishing object. Feature holding tool.   The holder according to claim 7, wherein the rotation mechanism includes a turntable to which the object to be polished is fixed.   The holder according to claim 8, further comprising a spacer that is disposed between the turntable and the object to be polished and projects a polishing surface of the object to be polished toward the polishing pad.   The holder according to claim 8 or 9, wherein the turntable is provided so as to protrude from the polishing head toward the polishing pad.   The said grinding | polishing head is comprised so that the said some grinding | polishing target object can be hold | maintained, The holding tool as described in any one of Claims 7-10 characterized by the above-mentioned.