JP7469735B2 - 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 increase the smoothness of the surface of an object to be polished, such as a glass plate, 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 contained in the polishing slurry.

JP 2003-145402 A

When the polishing pad is pressed against the workpiece, the tip surface of the protruding portion of the polishing pad is pressed against the workpiece, so the shape of the protruding portion has a significant impact on the efficiency of polishing. The shape of the protruding portion of conventional polishing pads still leaves room for improvement in terms of increasing the efficiency of polishing and extending the life of the polishing pad.

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

The polishing pad that solves the above problem comprises a base layer and a polishing layer laminated on the main surface of the base layer, and polishes the workpiece by rotating relative to the workpiece, the polishing layer having a plurality of protrusions and grooves arranged between the protrusions, and the bottom of the grooves is located in the base layer.

Conventionally, when a polishing pad rotates, the force caused by centrifugal force reduces the adhesion between the polished object and the polishing pad. As a result, the polished object may not be polished uniformly. By forming grooves all the way to the base layer as in this configuration, the polished object becomes more easily caught in the grooves, improving adhesion.

The base layer preferably comprises a hard layer and an elastic layer laminated on the surface of the hard layer, and the polishing layer is preferably laminated on the main surface of the elastic layer.

The above configuration prevents the workpiece from being damaged during polishing.

It is preferable that the bottom of the groove is disposed in the elastic layer.

The above configuration can prevent the workpiece from being scratched during polishing. In addition, because it has a hard layer, it is easier for the polishing pad to press the workpiece, improving polishing efficiency.

It is preferable that the protrusion has a recess that opens to the tip side, and an annular wall portion that is annular in shape surrounding the recess in a plan view and has a planar tip surface.

The workpiece is polished intensively near the corners on the front side in the relative rotation direction at the tips of the protrusions provided on the polishing layer of the polishing pad. As in the above configuration, in the protrusions having recesses opening to the tip side, in addition to the corners connected to the side surfaces facing forward in the relative rotation direction, some of the corners connected to the inner surfaces of the recesses facing forward in the relative rotation direction also become the corners on the front side in the relative rotation direction at the tips of the protrusions. By increasing the number of corners on the front side in the relative rotation direction, which is the part of the protrusions where strong polishing is performed, the polishing efficiency by the protrusions is improved.
In addition, the protrusion is provided with an annular wall portion that surrounds the recess and has a flat tip surface. This prevents the strength of the protrusion from being excessively reduced due to the formation of the recess, and prevents the protrusion from being broken early, for example, from losing its shape or peeling off from the polishing layer. This allows the protrusion to be used for a longer period of time than when the number of protrusions is increased to increase the number of corners.

It is preferable that the recess has an elongated shape that extends in a direction intersecting the relative rotation direction of the polishing pad in a plan view.

With the above configuration, the corners that connect to the inner side of the recess facing forward in the relative rotation direction of the polishing pad can be formed over a wide range in the direction that intersects with the relative rotation direction. This further improves the polishing efficiency of the protrusions.

It is preferable that the inner surface of the recess facing the front side in the relative rotation direction of the polishing pad is an inclined surface that slopes backward in the relative rotation direction from the base end toward the tip end.

According to the above configuration, when the polishing pad and the workpiece are rotated relative to each other, the vicinity of the corner connected to the inclined inner surface of the protrusion is pressed favorably against the workpiece, making the vicinity of the corner easily usable for polishing the workpiece.

It is preferable that multiple recesses are provided for one protrusion.

The above configuration improves the strength of the protrusion compared to when one large recess is formed. In addition, the polishing efficiency of the protrusion is improved by increasing the number of corners on the front side in the relative rotation direction, which is the area where polishing is more intense in the protrusion.

The polishing method that solves the above problem polishes the object by rotating the polishing pad and the object relative to each other.

The present invention improves polishing efficiency and enables longer-term use.

FIG. FIG. 2 is an enlarged view of part A in FIG. Cross-sectional view taken along line 3-3 in Figure 2. FIG. 2 is a schematic front view showing an example of a polishing pad in use; FIG. 4 is an explanatory diagram showing a protruding portion during polishing. FIG. FIG. FIG.

One embodiment of the polishing pad will be described below with reference to the drawings. Note that in the drawings, for the sake of convenience, some of the components may be exaggerated. Also, the dimensional ratios of each part may differ from the actual ones.

As shown in Figures 1 to 3, the polishing pad 11 has a circular inner peripheral edge 11a and a circular outer peripheral edge 11b. The polishing pad 11 has 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 by rotating relative to the object.

<Base layer>
As shown in Fig. 3, the base layer 12 of the polishing pad 11 has a two-layer structure including a hard layer 12a and an elastic layer 12b that is more easily deformed by compression than the polishing layer 13. The hard layer 12a is made of, for example, aluminum, stainless steel, etc. The elastic layer 12b is made of rubber or elastomer. The elastic layer 12b may be a non-foamed material or a foamed material. The elastic layer 12b has a lower hardness than the hard layer 12a. The hard layer 12a and the elastic layer 12b are bonded together via an adhesive layer (not shown).

<Polishing layer>
As shown in Fig. 3, the polishing layer 13 is laminated on the surface of the elastic layer 12b side of the base layer 12 to form the main surface of one side (upper side of the paper in Fig. 3) of the polishing pad 11. The polishing layer 13 includes a flat support portion 14 supported by the base layer 12 and a plurality of protrusions 15 protruding 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 formed from an elastic material such as urethane rubber. The polishing layer 13 and the base layer 12 are bonded together via an adhesive layer (not shown).

2 and 3, the protrusion 15 of the polishing layer 13 has a parallelogram-shaped tip surface 20, a first side surface 21 connected to the tip surface 20, a second side surface 22 which is the surface opposite to the first side surface 21, and a third side surface 23 and a fourth side surface 24 which connect the first side surface 21 and the second side surface 22. The tip surface 20 of the protrusion 15 is a flat surface parallel to the main surface PS of the base layer 12. The tip surface 20 may be inclined, for example, at an angle of about ±5° or less depending on the state of the main surface PS of the base layer 12 and the dimensional error of the polishing layer 13.

As shown in FIG. 1, the polishing layer 13 has multiple regions with different arrangements of the protrusions 15. The multiple regions are sectors 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 regions A1, A2, A3, A4, A5, and A6 in clockwise order in FIG. 1. Regions A1 and A4, regions A2 and A5, and regions A3 and A6 are arranged to face each other across the center in a plan view of the polishing pad 11.

As shown in Figs. 1 and 2, when the vertical direction in Fig. 1 is taken as the reference radial direction D1, each protrusion 15 in areas A1 and A4 is provided such that the first side 21 and the second side 22 extend along the radial direction D1. As shown in Fig. 1, in areas A1 and A4, multiple rows of multiple protrusions 15 spaced apart in the radial direction D1 are arranged in a direction perpendicular to the radial direction D1.

Each protrusion 15 in regions A2 and A5 is provided such that the first side 21 and the second side 22 extend along a radial direction D2 rotated 60° clockwise from the radial direction D1. In regions A2 and A5, a row of a plurality of protrusions 15 spaced apart in the radial direction D2 is arranged in a direction perpendicular to the radial direction D2.

Each protrusion 15 in regions A3 and A6 is provided such that the first side 21 and the second side 22 extend along a radial direction D3 rotated 120° clockwise from the radial direction D1. In regions A3 and A6, a row of a plurality of protrusions 15 spaced apart in the radial direction D3 is arranged 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, i.e., 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 is an inclined surface in which the first angle θ1, which is an angle with respect to the main surface PS of the base layer 12, is an acute angle. The first angle θ1 is, for example, preferably 80° or less, more preferably 70° or less, and even more preferably 60° or less. This first angle θ1 is preferably 10° or more, more preferably 20° or more, and even 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 layer 12, is not particularly limited, but is preferably larger than the first angle θ1 described above, and more preferably is larger than the first angle θ1 described above and is a right angle or an acute angle.

The first angle θ1 and the second angle θ2 described above indicate angles in a cross section perpendicular to the direction in which the first side surface 21 of each protrusion 15 extends. In addition, when the main surface PS of the base layer 12 has irregularities, a virtual plane perpendicular to the axial direction of the relative rotation between the polishing pad 11 and the workpiece to be polished corresponds to the main surface PS that is the basis for the angles.

As shown in Figures 2 and 3, each protrusion 15 has a recess 25 that opens into the tip surface 20, and an annular wall portion that surrounds the recess 25 in a plan view. The annular wall portion is made up of a wall portion 21a that forms the first side surface 21, a wall portion 22a that forms the second side surface 22, a wall portion 23a that forms the third side surface 23, and a wall portion 24a that forms the fourth side surface 24. The planar tip surface 20 of the protrusion 15 is formed by the tip surfaces of the walls 21a to 24a that make up the annular wall portion.

In a 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. In this embodiment, the elongated shape is an elliptical shape. That is, the length L1 of the recess 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 perpendicular to the same direction. For example, the length L1 is preferably 2 to 5 times the length L2. In addition, the length L1 is preferably 20 to 90% of the length in the direction along the first side surface 21 of the protrusion 15.

The depth L 3 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 tip 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 of the relative rotation direction RD, and the second inner surface 27 is an inner surface facing the front side of 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 layer 12, is not particularly limited, but is preferably larger than the first angle θ1 described above, and is more preferably larger than the first angle θ1 and is 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 layer 12, is a right angle.

<Grooves in polishing pads>
1, the groove 16 of the polishing pad 11 includes a main groove 16a that extends linearly from the inner peripheral end 11a to the outer peripheral end 11b of the polishing pad 11, and a branch groove 16b that linearly connects the main groove 16a and the outer peripheral end 11b of the polishing pad 11. The main groove 16a and the branch groove 16b form 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 the protrusion 15 and the adjacent protrusion 15. The groove 16 of the polishing pad 11 is composed of 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 layer 12. The second groove 16d is formed in a portion where the polishing layers 13 are spaced apart, and is a portion where the base layer 12 is exposed between the protrusion 15 and the adjacent protrusion 15. In other words, the polishing layer 13 is composed of a plurality of polishing layers 13 arranged at a distance on the base layer 12, and the polishing pad 11 has a second groove 16d configured with the base layer 12 as the inner bottom. In FIG. 1, the second groove 16d is shown with a matte pattern to distinguish it from the first groove 16c and the second groove 16d. The main surface PS of the base layer 12 at a position corresponding to the second groove 16d is recessed compared to other portions. This recessed portion becomes the bottom B of the second groove 16d. The bottom B of the second groove 16d is located in the elastic layer 12b.

<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, for example, in a plan view, is a length along the first side surface 21 of approximately 5 to 50 mm, a length in a direction perpendicular to the direction along the first side surface 21 of approximately 3 to 20 mm, and a height of approximately 5 to 30 mm based on the main surface PS.

The length L1 of the recess 25 of the protrusion 15 is, for example, about 3 to 15 mm, the length L2 of the recess 25 is, for example, about 1.5 to 5 mm, and the depth L3 of the recess 25 is, for example, 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. In addition, the width H1 of the walls 21a, 22a at the tip 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 form the recess 25 larger.

<Method of Use of Polishing Pad and Function of Polishing Pad>
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 the relative rotation of 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. In addition, a polishing slurry containing abrasive grains is used in such polishing.

Figure 4 shows an example of the usage state of the polishing pad 11. The polishing pad 11 is attached to the rotating shaft RS of the polishing machine. A glass plate GS as a polished object is fixed on a support table B. A 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 central through hole of the polishing pad 11. The polishing pad 11 is rotated in a direction proceeding against the glass plate GS with the first side surface 21 of each protrusion 15 in the polishing layer 13 at the front. This polishes the upper surface of the glass plate GS. At this time, the groove 16 of the polishing pad 11 becomes a flow path for the polishing slurry. In addition, since the bottom B of the second groove 16d is arranged in the base layer 12, the second groove 16d is deeper than the conventional one. Therefore, when the polishing pad 11 is pressed against the glass plate GS and rotated, the glass plate GS and the bottom B of the second groove 16d are likely to get caught. The adhesion between the glass plate GS and the polishing pad 11 can be prevented from decreasing due to the centrifugal force generated by the rotation of the polishing pad 11. In particular, since the bottom B of the second groove 16d is disposed on the elastic layer 12b, the occurrence of scratches caused by contact between the glass plate GS and the base layer 12 can be prevented. In addition, if the elastic layer 12b is made of a material that is easily compressed and deformed, the glass plate GS is more likely to bite into the elastic layer 12b, so that the glass plate GS is more likely to be caught and the decrease in adhesion can be further prevented. As a method for deepening the second groove 16d, it is possible to raise the polishing layer 13 and place the bottom of the second groove 16d on the polishing layer 13. However, in this case, it becomes difficult to discharge the polishing slurry SL.

Here, the glass sheet GS is strongly polished by the protruding portion 15 in the vicinity of the corner portion on the front side in the relative rotation direction RD at the tip of the protruding portion 15 .
5, each protrusion 15 in the polishing layer 13 of the polishing pad 11 of this embodiment has a recess 25 that opens to the tip surface 20. Therefore, at the tip of the protrusion 15, there are two corners on the front side in the relative rotation direction RD: a corner C1 that continues to the first side surface 21 and a corner C2 that continues to the second inner side surface 27, and strong polishing is performed near each of these two corners C1 and C2. By increasing the area of the protrusion 15 where strong polishing is performed, the polishing efficiency by the protrusion 15 is improved.

The recesses 25 of each protrusion 15 also function as slurry pockets that temporarily hold the polishing slurry SL. In other words, the polishing slurry SL supplied between the upper surface of the glass plate GS and the polishing layer 13 enters the recesses 25, and a portion of it is held within the recesses 25. This makes it easier to ensure that the polishing slurry SL is present between the glass plate GS and the vicinity of the corners C1 and C2 of the protrusion 15.

Two types of polishing pads were produced, the only difference being whether or not each protrusion 15 had a recess 25. The polishing efficiency of the two polishing pads was compared, and it was confirmed that providing each protrusion 15 with a recess 25 improved the polishing efficiency by approximately 8 to 9%.

In more detail, a glass plate was continuously conveyed at a constant speed and 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 with a recess 25 on each protrusion 15 and a polishing pad without a recess 25 on each protrusion 15, and the amount of reduction in the thickness of the glass plate due to polishing was measured. The average amount of reduction when a polishing pad without a recess 25 on each protrusion 15 was used was 9.02 μm, whereas the average amount of reduction when a polishing pad with a recess 25 on each protrusion 15 was used was 9.75 μm.

In FIG. 5, the change in shape of the polishing pad during polishing is not taken into consideration in order to depict the protruding portion 15 in a schematic manner. However, in reality, the polishing layer 13 deforms, and the bottom B of the second groove 16d comes into contact with the glass plate GS. The base layer 12 is more likely to transmit pressure to the glass plate GS than the protruding portion 15 of the polishing layer 13, so the glass plate GS is more likely to get caught in the second groove 16d. This improves the adhesion between the glass plate GS and the polishing pad 11. In addition, the bottom B of the second groove 16d is located on the elastic layer 12b, so the glass plate is less likely to be scratched and is easier to press. This improves the adhesion between the polishing pad 11 and the glass plate GS, which is the object to be polished, during polishing.

Next, the effects of this embodiment will be described.
(1) The polishing layer 13 has a plurality of protrusions 15 and second grooves 16d arranged between the protrusions 15, and the bottom B of the second grooves 16d is positioned in the elastic layer 12b of the base layer 12.

With the above configuration, the glass plate GS, which is the object to be polished, is more likely to be caught in the second groove 16d during polishing, improving adhesion between the polishing pad 11 and the glass plate GS.

(2) The base layer 12 comprises a hard layer 12a and an elastic layer 12b laminated on the surface of the hard layer 12a, and the polishing layer 13 is laminated on the main surface of the elastic layer 12b.

The above configuration prevents the glass plate GS from being damaged by contact with the base layer 12 of the polishing pad 11.

(3) It is preferable that the bottom B of the second groove 16d is disposed in the elastic layer 12b.

The above configuration can prevent the glass plate GS from being damaged by contact with the base layer 12 of the polishing pad 11. In addition, since the glass plate GS has the hard layer 12a, it becomes easier for the polishing pad 11 to press the glass plate GS, thereby improving the polishing efficiency.

(4) The polishing pad 11 has a polishing layer 13 having a protruding portion 15. The protruding portion 15 has a recessed portion 25 that opens to the tip side, and an annular wall portion that is annular in shape surrounding the recessed portion 25 in a plan view and has a planar tip surface 20.

According to the above-described configuration, the number of corners on the front side in the relative rotation direction RD, which are the portions of the protruding portion 15 that are strongly polished, is increased, thereby improving the polishing efficiency of the protruding portion 15.
In addition, an annular wall portion surrounding the recess 25 is provided for the protrusion 15. This prevents an excessive decrease in the strength of the protrusion 15 caused by the formation of the recess 25, and prevents the protrusion 15 from breaking early, for example, preventing the protrusion 15 from losing its shape or peeling off from the polishing layer 13. This allows for longer use than when the number of protrusions is increased to increase the number of corners.

(5) In a plan view, the recess 25 has a shape that extends in a direction that intersects with the relative rotation direction RD of the polishing pad 11.

With the above configuration, the corner portion C2 that connects to the second inner surface 27 of the protrusion 15 can be formed over a wide range in a direction intersecting the relative rotation direction RD. This further improves the polishing efficiency of the protrusion 15.

(6) The recess 25 has an elongated shape in a plan view, and its corners are rounded.

The above configuration makes it easier for the load acting on the protrusion 15 during polishing to be distributed throughout the entire annular wall. This further prevents the protrusion 15 from breaking prematurely.

(7) 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 a first side surface 21 that is connected to the tip surface 20 and has an inclined surface shape that forms an acute angle with respect to the main surface PS of the base layer 12. This first side surface 21 extends in a direction different from the relative rotation direction RD between the polishing pad 11 and the glass plate GS.

According to the above configuration, when the polishing pad 11 and the glass plate GS are rotated relative to each other, the vicinity of the corner C1 that connects to the inclined first side surface 21 of each protrusion 15 is suitably pressed against the glass plate GS. This makes it easier to use the vicinity of the corner C1 of the protrusion 15 for polishing the glass plate GS.

This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.
The shape of the recess 25 is not particularly limited, and various shapes such as the plan view shape and the cross-sectional shape may be changed as appropriate.

For example, as shown in FIG. 6, the second inner surface 27 of the recess 25 may be an inclined surface in which the fourth angle θ4, which is an angle with respect to the main surface PS of the base layer 12, is an acute angle. For example, the fourth angle θ4 is preferably 80° or less, more preferably 70° or less, and even more preferably 60° or less. Moreover, the fourth angle θ4 is preferably 10° or more, more preferably 20° or more, and even more preferably 30° or more. By setting the fourth angle θ4 to the above angle, the same effect as in (7) above can be obtained with respect to polishing in the vicinity of the corner C2 that is continuous with the second inner surface 27 of the protrusion 15.

In addition, in the above embodiment, the recess 25 has an elongated shape in a plan view that extends in a direction intersecting the relative rotation direction RD of the polishing pad 11, and the elongated shape is an elliptical shape. However, for example, the elongated shape may be a polygonal shape such as a rectangular shape that extends in a direction intersecting the relative rotation direction RD, or may be a shape other than a shape that extends in a direction intersecting the relative rotation direction RD, such as a circular shape or a square shape. Note that in this specification, a polygonal or elliptical ring shape also falls under the category of a ring.

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

Two or more recesses 25 may be provided for one protruding portion 15. When a plurality of recesses 25 are provided, the arrangement of the recesses 25 in the protruding portion 15 is not particularly limited.
For example, as shown in Fig. 7, the protruding portion 15 may have a plurality of recesses 25 aligned so as to overlap in the relative rotation direction RD, or as shown in Fig. 8, the protruding portion 15 may have a plurality of recesses 25 aligned so as not to overlap in the relative rotation direction RD. Also, the protruding portion 15 may have a plurality of recesses 25 aligned so as to overlap in the relative rotation direction RD, and a plurality of recesses 25 aligned so as not to overlap in the relative rotation direction RD.

Compared to providing one large recess 25 for the protrusion 15, providing multiple recesses 25 improves the strength of the protrusion 15 by forming walls that connect between the walls 21a to 24a that form each side of the protrusion 15.

In addition, as shown in FIG. 7, when multiple recesses 25 are provided on the protrusion 15 so as to overlap in the relative rotation direction RD, the number of corners on the front side of the protrusion 15 in the relative rotation direction RD, where polishing is performed strongly, further increases according to the number of recesses 25 formed. 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 planar 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 in which the first angle θ1, which is an acute angle relative to the main surface PS of the base layer 12, may be a vertical surface in which the first angle θ1 is a right angle.

All of the protrusions 15 may have the same shape, or some or all of them may have different shapes.
The base layer 12 of the polishing pad 11 may be such that the metal layer 12a or the elastic layer 12b is omitted.

- The polishing pad 11 is divided into areas A1 to A6 based on the direction in which each protrusion 15 extends, but is not limited to this, and the number and shape of the divided areas may be changed. Also, each protrusion 15 may extend radially from the center of the polishing pad without specifically setting areas on the polishing pad 11.

- The polishing pad 11 is rotated counterclockwise when viewed from the polishing layer 13 side in a plan view (Figure 1), but it may be changed to a polishing pad that is rotated clockwise.

By incorporating abrasive grains in each of the protrusions 15 of the polishing layer 13 of the polishing pad 11, the workpiece may be polished using water or the like as the polishing liquid instead of using a polishing slurry.
The object to be polished may be rotated to polish the object to be polished without rotating the polishing pad 11. The polishing pad 11 may be mounted on 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 layer, 13...polishing layer, 15...protrusion, 20...tip surface, 21...first side, 22...second side, 23...third side, 24...fourth side, 21a-24a...wall, 25...recess, 26...first inner surface, 27...second inner surface

Claims (6)

A polishing pad comprising a base layer and a polishing layer laminated on a main surface of the base layer, the polishing pad polishing an object to be polished by rotating relative to the object to be polished,
The polishing layer includes a plurality of protrusions and grooves disposed between the protrusions,
The protrusion includes a recess that opens to a tip end side, and an annular wall portion that is annular in shape surrounding the recess in a plan view and has a planar tip end surface,
the recess has an elongated shape extending in a direction intersecting a relative rotation direction of the polishing pad in a plan view,
The bottom of the groove is disposed on the base layer of the polishing pad. A polishing pad comprising a base layer and a polishing layer laminated on a main surface of the base layer, the polishing pad polishing an object to be polished by rotating relative to the object to be polished,
The polishing layer includes a plurality of protrusions and grooves disposed between the protrusions,
The protrusion includes a recess that opens to a tip end side, and an annular wall portion that is annular in shape surrounding the recess in a plan view and has a planar tip end surface,
an inner surface of the recess facing the front side in the relative rotation direction of the polishing pad is an inclined surface inclined toward the rear side in the relative rotation direction from the base end side toward the tip end side,
The bottom of the groove is disposed on the base layer of the polishing pad. A polishing pad comprising a base layer and a polishing layer laminated on a main surface of the base layer, the polishing pad polishing an object to be polished by rotating relative to the object to be polished,
The polishing layer includes a plurality of protrusions and grooves disposed between the protrusions,
The protrusion includes a recess that opens to a tip end side, and an annular wall portion that is annular in shape surrounding the recess in a plan view and has a planar tip end surface,
A plurality of the recesses are provided for one of the protrusions,
The bottom of the groove is disposed on the base layer of the polishing pad. The base layer includes a hard layer and an elastic layer laminated on a surface of the hard layer,
4. The polishing pad according to claim 1, wherein the polishing layer is laminated on a main surface of the elastic layer. 5. The polishing pad according to claim 4, wherein the bottom of the groove is disposed in the elastic layer. A polishing method for polishing an object by rotating the polishing pad according to any one of claims 1 to 5 relative to the object.