JP7351170B2 - Polishing pad and polishing method - Google Patents

Description

The present invention relates to a polishing pad and a polishing method.

As disclosed in Patent Document 1, in order to improve the smoothness of the surface of an object to be polished, such as a plate glass, the surface of the object to be polished is polished using a polishing pad. To polish an object to be polished using a polishing pad, the rotating polishing pad is brought into contact with the surface of the object to be polished. At this time, a polishing slurry is supplied between the polishing pad and the object to be polished, and the surface of the object to be polished is polished by the abrasive material contained in the polishing slurry.

Japanese Patent Application Publication No. 2003-145402

When the polishing pad is pressed against the object to be polished, the tip end surface of the protrusion of the polishing pad is pressed against the object to be polished, so the shape of the protrusion has a great influence on the efficiency of polishing. There is still room for improvement in the shape of the protrusion of conventional polishing pads from the viewpoint of increasing polishing efficiency and extending the life of the polishing pad.

The present invention has been made in view of these circumstances, and its purpose is to provide a polishing pad that increases polishing efficiency and can be used for a long period of time.

A polishing pad that solves the above problems is a polishing pad that polishes an object to be polished by relative rotation with the object, and includes a polishing layer having a protrusion, and the protrusion has a recess that opens toward the tip side. and an annular wall portion surrounding the recessed portion in plan view and having a planar tip end surface.

The object to be polished is intensively polished near the front corner in the relative rotation direction at the tip of the protrusion provided on the polishing layer of the polishing pad. As in the above configuration, the protrusion having the recess opening on the tip side has a corner connected to the side surface facing forward in the direction of relative rotation, as well as a corner connected to the inner surface facing forward in the direction of relative rotation in the recess. A part of the portion also becomes a corner portion on the front side in the relative rotation direction at the tip of the protruding portion. The polishing efficiency of the protrusion is improved by increasing the front corner in the relative rotation direction, which is a portion where the protrusion is strongly polished.

Further, an annular wall portion surrounding the recessed portion and having a planar tip end surface is provided for the protruding portion. This suppresses an excessive decrease in the strength of the protruding part due to the formation of the recess, and prevents the protruding part from breaking early, for example, the shape of the protruding part collapses, or the protruding part peels off from the polishing layer. can be suppressed. Therefore, it can be used for a longer period of time compared to the case where the number of protrusions is increased to increase the number of corners.

The recess preferably has an elongated shape extending in a direction intersecting the relative rotation direction of the polishing pad in plan view.
According to the above configuration, the corner portion that is connected to the inner surface of the concave portion facing the front side in the relative rotation direction of the polishing pad can be formed in a wide range in the direction intersecting the relative rotation direction with respect to the protrusion portion. This further improves the polishing efficiency of the protrusions.

The inner surface of the recess facing forward in the relative rotation direction of the polishing pad is preferably an inclined surface that slopes from the proximal end toward the distal end toward the rear in the relative rotation direction.
According to the above configuration, when the polishing pad and the object to be polished are rotated relative to each other, the vicinity of the corner connected to the inclined inner surface of the protrusion is suitably pressed against the object to be polished, and the corner The area around the area becomes easier to use for polishing the object to be polished.

Preferably, a plurality of the recesses are provided for one protrusion.
According to the above configuration, the strength of the protrusion is improved compared to the case where one large recess is formed. In addition, the polishing efficiency of the protrusion is improved by increasing the front corner in the relative rotation direction, which is a portion where the protrusion is strongly polished.

A polishing method for solving the above problem polishes the object to be polished by relatively rotating the polishing pad and the object to be polished.

According to the present invention, polishing efficiency can be increased and use for a longer period of time becomes possible.

FIG. 2 is a plan view showing a polishing pad. An enlarged view of part A in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 2 is a schematic front view showing an example of a polishing pad in use. An explanatory diagram showing a protrusion during polishing. FIG. 4 is a cross-sectional view of a protrusion in a modified example. FIG. 7 is a plan view of a protrusion in a modified example. FIG. 7 is a plan view of a protrusion in a modified example.

Hereinafter, one embodiment of a polishing pad will be described with reference to the drawings. Note that in the drawings, a part of the configuration may be shown in an exaggerated manner for convenience of explanation. Furthermore, the dimensional ratio of each part may also differ from the actual size.

As shown in FIGS. 1 to 3, the polishing pad 11 has a circular inner peripheral end 11a and a circular outer peripheral end 11b. The polishing pad 11 includes a base layer 12 and a polishing layer 13 laminated on the main surface PS of the base layer 12. The polishing pad 11 is used to polish an object to be polished by rotating relative to the object.

<Base material layer>
As shown in FIG. 3, the base layer 12 of the polishing pad 11 has a two-layer structure including a metal layer 12a and an elastic layer 12b that is more easily compressed and deformed than the polishing layer 13. The metal layer 12a is made of, for example, aluminum, stainless steel, or the like. The elastic layer 12b is made of rubber or elastomer. The elastic layer may be a non-foamed material or a foamed material. The metal layer 12a and the elastic layer 12b are bonded together via an adhesive layer.

<Polishing layer>
As shown in FIG. 3, the polishing layer 13 is laminated on the surface of the base layer 12 on the elastic layer side to form the main surface on one side (the upper side of the paper in FIG. 3) of the polishing pad 11. As shown in FIG. The polishing layer 13 includes a flat support portion 14 supported by the base layer 12 and a plurality of protrusions 15 that protrude from the support portion 14 toward one main surface of the polishing pad 11 . The support portion 14 and the plurality of protrusions 15 are integrally made of an elastic material such as urethane rubber. The polishing layer 13 and the base material layer 12 are bonded together via an adhesive layer.

As shown in FIGS. 2 and 3, the protrusion 15 of the polishing layer 13 has a parallelogram-shaped tip surface 20, a first side surface 21 continuous to the tip surface 20, and a surface opposite to the first side surface 21. It has a quadrangular prism shape having a certain second side surface 22, and a third side surface 23 and a fourth side surface 24 that connect the first side surface 21 and the second side surface 22. The tip surface 20 of the protrusion 15 has a planar shape parallel to the main surface PS of the base layer 12. Note that the tip surface 20 may be inclined at an angle within ±5°, for example, depending on the state of the main surface PS of the base material layer 12 and the dimensional error of the polishing layer 13.

As shown in FIG. 1, the polishing layer 13 has a plurality of regions in which the protrusions 15 are arranged differently. The plurality of regions are fan-shaped regions that are divided into six equal parts with a central angle of 60° in a plan view of the polishing layer 13, and the polishing pad 11 is divided into six areas in clockwise order in FIG. It is divided into A3, A4, A5, and A6. Area A1 and area A4, area A2 and area A5, and area A3 and area A6 are arranged so as to face each other with the center in between, when the polishing pad 11 is viewed from above.

As shown in FIGS. 1 and 2, when the vertical direction in FIG. 1 is the reference radial direction D1, each of the protrusions 15 in areas A1 and A4 has a first side surface 21 and a second side surface 22 in the radial direction D1. It is provided so as to extend along the line. As shown in FIG. 1, in areas A1 and A4, a plurality of rows of protrusions 15 are arranged spaced apart in the radial direction D1. There is.

Each of the protrusions 15 in the areas A2 and A5 is provided such that the first side surface 21 and the second side surface 22 extend along the radial direction D2 rotated by 60 degrees clockwise from the radial direction D1. In areas A2 and A5, a plurality of rows of protrusions 15 are arranged spaced apart in a direction perpendicular to the radial direction D2.

Each of the protrusions 15 in the regions A3 and A6 is provided such that the first side surface 21 and the second side surface 22 extend along the radial direction D3 rotated by 120 degrees clockwise from the radial direction D1. In areas A3 and A6, a plurality of rows of protrusions 15 are arranged spaced apart in a direction perpendicular to the radial direction D3.

As described above, the first side surface 21 and the second side surface 22 of each protrusion 15 extend in one of the radial directions D1, D2, and D3. Therefore, the first side surface 21 and the second side surface 22 of each protrusion 15 extend in a direction different from the relative rotation direction RD indicated by the arrow in FIG. 1, that is, in a direction intersecting the relative rotation direction RD. In this embodiment, the relative rotation direction RD coincides with the circumferential direction of the polishing pad 11.

<Protrusion>
As shown in FIG. 3, the first side surface 21 of each protrusion 15 is a side surface facing the front side in the relative rotation direction RD, and the first angle θ1, which is the angle with respect to the main surface PS of the base material layer 12, is an acute angle. It is an inclined surface. The first angle θ1 is, for example, preferably 80° or less, more preferably 70° or less, and still more preferably 60° or less. This first angle θ1 is preferably 10° or more, more preferably 20° or more, and still more preferably 30° or more.

In each protrusion 15, the second angle θ2, which is the angle of the second side surface 22 with respect to the main surface PS of the base material layer 12, is not particularly limited, but is preferably larger than the first angle θ1, and the second angle θ2 is preferably larger than the first angle θ1. It is more preferable that the angle is larger than the angle θ1 and is a right angle or an acute angle.

Note that the above-described first angle θ1 and second angle θ2 indicate angles in a cross section perpendicular to the direction in which the first side surface 21 of each protrusion 15 extends. Further, when the main surface PS of the base material layer 12 has unevenness, a virtual plane perpendicular to the axial direction of relative rotation between the polishing pad 11 and the object to be polished corresponds to the main surface PS serving as the reference for the angle. .

As shown in FIGS. 2 and 3, each protrusion 15 includes a recess 25 opening in the distal end surface 20 and an annular wall surrounding the recess 25 in plan view. The annular wall portion includes a wall portion 21a forming the first side surface 21, a wall portion 22a forming the second side surface 22, a wall portion 23a forming the third side surface 23, and a wall portion forming the fourth side surface 24. 24a. The planar tip surface 20 of the protrusion 15 is formed by the tip surfaces of the walls 21a to 24a forming the annular wall.

In plan view, the recess 25 is formed in an elongated shape extending in the direction in which the first side surface 21 and the second side surface 22 of the protrusion 15 extend. Note that in this embodiment, the elongated shape is an ellipse. That is, the length L1 of the recessed portion 25 in the direction in which the first side surface 21 and the second side surface 22 extend is longer than the length L2 in the direction orthogonal to the same direction. For example, the length L1 is preferably 2 to 5 times the length L2. Further, the length L1 is preferably 20 to 90% of the length of the protrusion 15 in the direction along the first side surface 21.

The depth L3 of the recess 25 is preferably 50 to 100% of the length from the main surface of the support portion 14, which is the base end of the protrusion 15, to the distal end surface 20.
The recess 25 has a first inner surface 26 located on the first side surface 21 side of the protrusion 15 and a second inner surface 27 located on the second side surface 22 side of the protrusion 15 . The first inner surface 26 is an inner surface facing the rear side in the relative rotation direction RD, and the second inner surface 27 is an inner surface facing the front side in the relative rotation direction RD. The third angle θ3, which is the angle of the first inner surface 26 with respect to the main surface PS of the base material layer 12, is not particularly limited, but is preferably larger than the first angle θ1, and is preferably larger than the first angle θ1. More preferably, it is large and has a right angle or an acute angle. The fourth angle θ4, which is the angle of the second inner surface 27 with respect to the main surface PS of the base material layer 12, is a right angle.

<Groove of polishing pad>
As shown in FIG. 1, the grooves 16 of the polishing pad 11 include a main groove 16a extending linearly from an inner circumferential end 11a to an outer circumferential end 11b of the polishing pad 11, and a main groove 16a and an outer circumferential end 11b of the polishing pad 11. and a branch groove 16b that linearly connects the two. The main groove 16a and the branch groove 16b constitute a continuous groove 16 between the inner peripheral end 11a and the outer peripheral end 11b of the polishing pad 11.

As shown in FIG. 3, the groove 16 of the polishing pad 11 is formed between one protrusion 15 and an adjacent protrusion 15. As shown in FIG. The groove 16 of the polishing pad 11 includes a first groove 16c having an inner bottom made of the polishing layer 13 and a second groove 16d having an inner bottom made of the base material layer 12. The second groove 16d is formed in a portion where the polishing layers 13 are separated from each other, and is a portion where the base material layer 12 is exposed between the protrusion 15 and the protrusion 15 adjacent thereto. In other words, the polishing layer 13 is composed of a plurality of polishing layers 13 spaced apart from each other on the base layer 12, and the polishing pad 11 has a second polishing layer 13 configured with the base layer 12 as an inner bottom. It has a groove 16d. In addition, in FIG. 1, the second groove 16d is shown in a matte pattern to distinguish it from the first groove 16c and the second groove 16d.

<Dimensions of polishing pad>
The dimensions of the polishing pad 11 and each part of the polishing pad 11 are not limited, but may be, for example, the dimensions described below.

The diameter of the polishing pad 11 is, for example, about 10 to 1000 mm.
The size of the protrusion 15 is, for example, in a plan view, the length in the direction along the first side surface 21 is about 5 to 50 mm, and the length in the direction perpendicular to the direction along the first side surface 21 is about 3 to 20 mm. The height is about 5 to 30 mm.

The length L1 of the recess 25 of the protrusion 15 is, for example, approximately 3 to 15 mm, the length L2 of the recess 25 is, for example, approximately 1.5 to 5 mm, and the depth L3 of the recess 25 is, for example, approximately 3 to 15 mm. It is about 3 to 8 mm.

The width H1 of the walls 21a, 22a at the tip surface 20 of the protrusion 15 is, for example, 3 mm or more, and the width H2 of the walls 23a, 24a is, for example, 1.5 mm or more. In this case, it is easy to ensure the strength of the protrusion 15. Further, the width H1 of the walls 21a and 22a at the tip end surface 20 of the protrusion 15 is, for example, 8 mm or less, and the width H2 of the walls 23a, 24a is, for example, 3 mm or less. In this case, it is easy to make the recess 25 larger.

<How to use the polishing pad and its function>
The polishing pad 11 is attached to, for example, a known polishing machine equipped with a rotary drive device. The surface of the object to be polished is polished by relative rotation between the polishing pad 11 and the object to be polished. Examples of the object to be polished include plate materials such as glass plates, stainless steel plates, and aluminum plates. Note that in such polishing, a polishing slurry containing abrasive grains is used.

FIG. 4 shows an example of how the polishing pad 11 is used. The polishing pad 11 is attached to the rotating shaft RS of the polishing machine. A glass plate GS as an object to be polished is fixed on a support base B. The polishing slurry SL is supplied between the upper surface of the glass plate GS and the polishing layer 13 through the hollow part of the rotating shaft RS and the through hole in the center of the polishing pad 11. The polishing pad 11 is rotated in a direction in which the first side surface 21 of each protrusion 15 in the polishing layer 13 is at the front and advances relative to the glass plate GS. As a result, the upper surface of the glass plate GS is polished. At this time, the grooves 16 of the polishing pad 11 serve as flow paths for the polishing slurry.

Here, the glass plate GS is strongly polished by the protrusion 15 near the front corner of the tip of the protrusion 15 in the relative rotation direction RD.
As shown in FIG. 5, each protrusion 15 in the polishing layer 13 of the polishing pad 11 of this embodiment has a recess 25 opening to the tip surface 20. As shown in FIG. Therefore, at the tip of the protrusion 15, there are two corners as front corners in the relative rotation direction RD: a corner C1 connected to the first side surface 21 and a corner C2 connected to the second inner side surface 27. As a result, strong polishing is performed in the vicinity of these two corner portions C1 and C2. By increasing the portion of the protrusion 15 that is subjected to strong polishing, the polishing efficiency of the protrusion 15 is improved.

Further, the recess 25 of each protrusion 15 also functions as a slurry pocket that temporarily holds the polishing slurry SL. That is, the polishing slurry SL supplied between the upper surface of the glass plate GS and the polishing layer 13 enters the recess 25 and a portion thereof is retained within the recess 25 . This makes it easier to ensure that the polishing slurry SL exists between the vicinity of the corners C1 and C2 of the protrusion 15 and the glass plate GS.

In addition, when two types of polishing pads were prepared that differed only in whether or not each protrusion 15 was provided with a recess 25, and the polishing efficiency of both polishing pads was compared, it was found that each protrusion 15 was provided with a recess 25. As a result, it was confirmed that the polishing efficiency was improved by about 8 to 9%.

Specifically, a glass plate that was continuously conveyed at a constant speed was polished for 8 hours using a polishing machine equipped with a polishing pad. The above operation was performed 21 times each using a polishing pad in which each protrusion 15 was provided with a recess 25 and a polishing pad in which each protrusion 15 was not provided with a recess 25. The amount of decrease in thickness was measured. The average value of the reduction amount when using a polishing pad in which each protrusion 15 is not provided with a recess 25 is 9.02 μm, whereas in the case where each protrusion 15 is provided with a recess 25 The average value of the reduction amount when using a polishing pad was 9.75 μm.

Next, the effects of this embodiment will be described.
(1) The polishing pad 11 includes a polishing layer 13 having a protrusion 15. The protrusion 15 includes a recess 25 that opens toward the distal end, and an annular wall that surrounds the recess 25 in plan view and has a planar end surface.

According to the above configuration, the corner portion on the front side in the relative rotation direction RD, which is a portion of the protrusion 15 that is strongly polished, increases. This improves the polishing efficiency of the protrusion 15.
Furthermore, an annular wall surrounding the recess 25 is provided for the protrusion 15 . This suppresses an excessive decrease in the strength of the protrusion 15 due to the formation of the recess 25, and prevents the protrusion 15 from breaking early, for example, the shape of the protrusion 15 collapses, or the protrusion 15 is removed from the polishing layer. It is possible to suppress peeling off from 13. Therefore, compared to the case where the number of protruding parts is increased to increase the number of corner parts, it is possible to use the product for a longer period of time.

(2) The recess 25 has a shape extending in a direction intersecting the relative rotation direction RD of the polishing pad 11 when viewed from above.
According to the above configuration, the corner C2 of the protrusion 15 that is continuous with the second inner surface 27 can be formed over a wide range in the direction intersecting the relative rotation direction RD. This further improves the polishing efficiency of the protrusion 15.

(3) The recess 25 has an elongated shape in plan view, and its corners are rounded.
According to the above configuration, the load acting on the protrusion 15 during polishing is easily dispersed over the entire annular wall. Thereby, it is possible to further suppress the protrusion 15 from breaking at an early stage.

(4) Each protrusion 15 in the polishing layer 13 of the polishing pad 11 has a tip surface 20 that is parallel to the main surface PS of the base layer 12, and is connected to the tip surface 20 and at an angle with respect to the main surface PS of the base layer 12. The first side surface 21 has an inclined surface shape and has an acute angle. This first side surface 21 extends in a direction different from the relative rotation direction RD between the polishing pad 11 and the object to be polished.

According to the above configuration, when the polishing pad 11 and the object to be polished are rotated relative to each other, the vicinity of the corner C1 continuous to the inclined first side surface 21 of each protrusion 15 is suitably pressed against the object to be polished. be done. This makes it easier to use the vicinity of the corner C1 of the protrusion 15 for polishing the object to be polished.

Note that this embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- The shape of the recessed portion 25 is not particularly limited, and various shapes such as its plan view shape and cross-sectional shape may be changed as appropriate.

For example, as shown in FIG. 6, the second inner side surface 27 of the recess 25 may be an inclined surface where the fourth angle θ4, which is the angle with respect to the main surface PS of the base material layer 12, is an acute angle. The fourth angle θ4 is, for example, preferably 80° or less, more preferably 70° or less, and even more preferably 60° or less. Further, the fourth angle θ4 is preferably 10° or more, more preferably 20° or more, and still more preferably 30° or more. By setting the fourth angle θ4 to the above-mentioned angle, the same effect as in (4) above can be obtained regarding polishing in the vicinity of the corner C2 of the protrusion 15 that is connected to the second inner surface 27.

Further, the recess 25 in the above embodiment has an elongated shape extending in a direction intersecting the relative rotation direction RD of the polishing pad 11 in plan view, and the elongated shape is an oval shape. It may be a polygonal shape such as a rectangular shape extending in a direction intersecting the rotational direction RD, or a shape other than a shape extending in a direction intersecting the relative rotational direction RD, such as a perfect circular shape or a square shape. In addition, in this specification, a polygonal shape or an elliptical shape also corresponds to a ring shape.

- The recess 25 may be a through hole that penetrates the polishing layer 13 and reaches the base layer 12.
- The recesses 25 provided in each protrusion 15 may all have the same shape, or may have partially or entirely different shapes.

- Two or more recesses 25 may be provided for one protrusion 15. When providing a plurality of recesses 25, the arrangement of each recess 25 in the protrusion 15 is not particularly limited.
For example, as shown in FIG. 7, the protrusion 15 may have a plurality of recesses 25 arranged so as to overlap in the relative rotation direction RD, or as shown in FIG. The protrusion 15 may have a recess 25 . Further, the protrusion 15 may have a plurality of recesses 25 lined up so as to overlap in the relative rotation direction RD and a plurality of recesses 25 lined up so as not to overlap in the relative rotation direction RD.

Compared to the case where one large recess 25 is provided for the protrusion 15, when a plurality of recesses 25 are provided, the walls 21a to 24a forming each side surface of the protrusion 15 are connected. The strength of the protruding portion 15 is improved by forming the wall portion.

Further, as shown in FIG. 7, when a plurality of recesses 25 are provided in the protrusion 15 so as to overlap in the relative rotation direction RD, polishing in the protrusion 15 is performed depending on the number of recesses 25 formed. The corner portion on the front side in the relative rotation direction RD, which is a portion where the rotation is strongly performed, further increases. This further improves the polishing efficiency of the protrusion 15.

- The shape of the protrusion 15 is not particularly limited, and various shapes such as its plan view shape and cross-sectional shape may be changed as appropriate. For example, the first side surface 21 of the protrusion in the above embodiment is an inclined surface where the first angle θ1, which is the angle with respect to the main surface PS of the base material layer 12, is an acute angle, but the first angle θ1 is a right angle. It may be a vertical plane.

- All the protrusions 15 may have the same shape, or some or all of them may have different shapes.
- The base material layer 12 of the polishing pad 11 may be one in which the elastic layer 12b is omitted.

- Although the polishing layer 13 of the polishing pad 11 is composed of a plurality of polishing layers 13 spaced apart from each other on the base material layer 12, it may be composed of a single polishing layer 13 that is integrated.
- Although the polishing pad 11 is divided into regions A1 to A6 based on the extending direction of each protrusion 15, the present invention is not limited to this, and the number and shape of the divided regions may be changed. Alternatively, each protrusion 15 may extend radially from the center of the polishing pad without specifically setting a region on the polishing pad 11.

- The polishing pad 11 is used by being relatively rotated counterclockwise when viewed from the polishing layer 13 side (FIG. 1); May be changed.

- By containing abrasive grains in each protrusion 15 of the polishing layer 13 of the polishing pad 11, the object to be polished may be polished using water or the like as a polishing liquid without using a polishing slurry.
- The object to be polished may be polished by rotating the object to be polished without rotating the polishing pad 11. Further, the polishing pad 11 may be used by being attached to a polishing machine that uses a planetary gear mechanism to simultaneously rotate a plurality of polishing pads.

GS... Glass plate, PS... Main surface, RD... Relative rotation direction, 11... Polishing pad, 12... Base material layer, 13... Polishing layer, 15... Projection, 20... Tip surface, 21... First side surface, 22... Second side surface, 23... Third side surface, 24... Fourth side surface, 21a to 24a... Wall portion, 25... Recessed portion, 26... First inner surface, 27... Second inner surface.

Claims (4)

A polishing pad that polishes an object to be polished by relative rotation with the object to be polished,
A polishing layer having a plurality of protrusions and grooves formed between the adjacent protrusions ,
The protrusion has a rectangular prism shape having a tip surface and a first side surface that is continuous with the tip surface and extends in a direction intersecting the relative rotation direction of the polishing pad,
The protrusion includes a recess opening in the tip surface , and an annular wall portion surrounding the recess in a plan view, and the tip surface is planar .
The polishing pad is characterized in that the recess has an elongated shape extending in the direction in which the first side surface extends in plan view . The polishing according to claim 1 , wherein the inner surface of the recess facing forward in the relative rotation direction of the polishing pad is an inclined surface that slopes from the proximal end toward the distal end toward the rear in the relative rotation direction. pad. The polishing pad according to claim 1 or 2, wherein a plurality of said recesses are provided for one said protrusion. A polishing method for polishing the object to be polished by relatively rotating the polishing pad according to any one of claims 1 to 3 and the object to be polished.