JP7087365B2 - Polishing pad - Google Patents

Description

The present invention relates to a polishing pad.

The smoothness on the surface of an object to be polished such as flat glass is enhanced by polishing the surface of the object to be polished with a polishing pad. To polish the object to be polished using the 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 polishing material contained in the slurry for polishing. Such a polishing pad has a base material layer and a polishing layer that comes into contact with the object to be polished. Patent Document 1 discloses a configuration in which a groove or a gap is provided in a polishing layer (corresponding to the “polishing pad” of Patent Document 1) so as to suppress retention of the polishing slurry.

Japanese Unexamined Patent Publication No. 2003-145402

By the way, when the polishing pad is pressed against the object to be polished, the tip surface of the protruding portion of the polishing pad is pressed against the object to be polished. , It is possible to increase the efficiency of polishing. However, in this case, the problem that the tip surface of the protruding portion is caught by the object to be polished and the object to be polished is likely to fly is likely to occur. Therefore, there is still room for improvement in the shape of the protrusion of the polishing pad.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a polishing pad that can easily improve the efficiency of polishing.

The polishing pad that solves the above problems is a polishing pad that has a base material layer and a polishing layer laminated on the main surface of the base material layer, and polishes the object to be polished by relative rotation with the object to be polished. In the polishing layer, protrusions having a tip surface parallel to the main surface of the base material layer are arranged in a predetermined pattern, and the width of the protrusion gradually increases in a specific direction toward the tip side. It includes a tapered first protrusion that is shortened, and a second protrusion whose tip surface has a width in the specific direction longer than the first protrusion.

According to the above configuration, as the protrusions, a first protrusion and a second protrusion having different widths of the tip surfaces are provided. Therefore, even when the tip surface of the second protrusion is formed large in order to improve the efficiency of polishing, the contact area of the first protrusion with respect to the object to be polished is small, and the contact pressure is small due to the bending due to the tapered shape. Excessive catching on the object to be polished is suppressed by the presence of the portion. As a result, the problem of skipping the object to be polished, which occurs when the tip surface of the protruding portion is formed to be large, is suppressed, and the polishing pad can easily improve the efficiency of polishing.

In the polishing pad, the first protruding portion is arranged so that one side in the specific direction is located on the front side in the rotation direction, and the first protruding portion is inclined so that the angle with respect to the main surface of the base material layer is sharp on the front side in the rotation direction. The second projecting portion has a surface and a cross-sectional shape orthogonal to the inclined surface is trapezoidal, and the second protruding portion is arranged so that one side in the specific direction is located on the front side in the rotation direction, and the second protrusion is located on the front side in the rotation direction. It is preferable that the base material layer has a right-angled surface at a right angle to the main surface and the cross-sectional shape orthogonal to the right-angled surface is rectangular.

According to the above configuration, the effect of suppressing excessive catching on the object to be polished by the first protruding portion and the effect of improving the polishing efficiency by enlarging the tip surface of the second protruding portion are further improved.
In the polishing pad, it is preferable that the first protruding portion and the second protruding portion have a parallel quadrilateral shape in a plan view.

According to the above configuration, the polishing slurry easily flows between the first protruding portion and the second protruding portion, and the polishing efficiency is improved.
In the polishing pad, the polishing layer has an inner region located on the inner side in the radial direction and an outer region located on the outer side in the radial direction and having a contact area per unit area with respect to the object to be polished larger than the inner region. In the inner region, only the first protrusion is arranged in a predetermined pattern as the protrusion, and in the outer region, the first protrusion and the second protrusion are arranged in a predetermined pattern as the protrusion. It is preferable that it is arranged.

The second protruding portion formed with a long tip surface has high polishing efficiency, but is liable to be excessively caught on the object to be polished. By arranging such a second protrusion in combination with the first protrusion only in the outer region where the moving distance per rotation is long in the polishing layer, the effect of improving the polishing efficiency and the effect of suppressing excessive catching are at a high level. Can be compatible with.

In the polishing pad, the inner region preferably has a polygonal shape that is rotationally symmetric in a plan view.
According to the above configuration, when the polishing pad is rotated, it is suppressed that a portion where only the outer periphery of the inner region (the boundary portion between the inner region and the outer region) continues to pass is suppressed, and polishing unevenness is less likely to occur.

In the polishing pad, in the outer region, the first protrusion and the second protrusion are alternately arranged so that the first protrusion is located on the front side in the rotation direction of the second protrusion. It is preferable to have.

According to the above configuration, the effect of improving the polishing efficiency and the effect of suppressing excessive catching can be achieved at a high level.

According to the present invention, it becomes easy to increase the efficiency of polishing.

Top view showing the polishing pad. Enlarged view of area A1. FIG. 2 is a sectional view taken along line 3-3. FIG. 2 is a sectional view taken along line 4-4 of FIG. The schematic front view which shows an example of the use state of a polishing pad.

Hereinafter, an embodiment of the polishing pad will be described with reference to the drawings. In the drawings, a part of the configuration may be exaggerated for convenience of explanation. In addition, the dimensional ratio of each part may differ from the actual one.

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

<Base layer>
The base material layer 12 of the polishing pad 11 has a two-layer structure including a metal layer and an elastic layer that is more easily compressed and deformed than the polishing layer 13 (not shown). The metal layer is made of, for example, aluminum, stainless steel, or the like. The elastic layer is composed of rubber or elastomer. The elastic layer may be a non-foamed material or a foamed material. The metal layer and the elastic layer are adhered to each other via an adhesive layer.

<Abrasive layer>
As shown in FIG. 3, the polishing layer 13 of the polishing pad 11 is laminated on the surface of the base material layer 12 on the elastic layer side. The polishing layer 13 includes a flat plate-shaped support portion 14 supported by the base material layer 12, and a plurality of projecting portions 15 projecting from the support portion 14. The support portion 14 and the plurality of projecting portions 15 are integrally formed of an elastic material such as urethane rubber. The polishing layer 13 and the base material layer 12 are adhered to each other via an adhesive layer.

As shown in FIGS. 1 and 2, the protruding portion 15 of the polishing layer 13 is formed in a parallelogram shape in a plan view. The polishing pad 11 has a plurality of regions in which the arrangement pattern of the protrusions 15 is different. More specifically, the polishing pad 11 is a fan-shaped region divided into six equal parts with a central angle of 60 ° in a plan view of the polishing layer 13, and the regions A1, A2, A3, and A4 are in the clockwise order in FIG. , A5, A6. The regions A1 and A4, the regions A2 and A5, and the regions A3 and A6 are arranged so as to face each other in the plan view of the polishing pad 11.

The protruding portions 15 of the regions A1 and A4 are arranged side by side so as to be separated from each other in the radial direction D1 and the radial direction D1 when the vertical direction of the paper surface in FIG. 1 is set as the reference radial direction D1. The protruding portions 15 of the regions A2 and A5 are arranged side by side so as to be separated from each other in the radial direction D2 and the radial direction D2 when the direction rotated by 60 ° clockwise from the radial direction D1 is the radial direction D2. ing. The protruding portions 15 of the regions A3 and A6 are arranged side by side so as to be separated in the radial direction D3 and the direction orthogonal to the radial direction D3 when the direction rotated by 120 ° clockwise from the radial direction D1 is the radial direction D3. ing.

As shown in FIGS. 1 and 2, each of the regions A1 to A6 has an inner region Aa located on the inner side in the radial direction and an outer region Ab located on the outer side in the radial direction. The arrangement pattern of the protrusions 15 is different between the inner region Aa and the outer region Ab. As shown in FIG. 1, the shape of the entire inner region Aa including the inner regions Aa of the regions A1 to A6 is a star-shaped polygon (hexagram shape) which is a kind of rotationally symmetric polygon. Further, in a plan view, the ratio of the inner region Aa to the total area of the inner region Aa and the outer region Ab is, for example, 30 to 55%.

<Protruding part>
As shown in FIGS. 2 to 4, the protruding portion 15 includes a first protruding portion 16 and a second protruding portion 17 having different shapes. The first protrusion 16 is arranged in both the inner region Aa and the outer region Ab, and the second protrusion 17 is arranged only in the outer region Ab.

As shown in FIGS. 3 and 4, the first protruding portion 16 has a tip surface 16a parallel to the main surface PS of the base material layer 12, a first side surface 16b connected to the tip surface 16a, and a first side surface 16b thereof. It has a second side surface 16c, which is the opposite surface of the above. The first side surface 16b is an inclined surface having an acute angle of the first angle θ1 with respect to the main surface PS of the base material layer 12. The second side surface 16c is a right-angled surface at which the second angle θ2 with respect to the main surface PS of the base material layer 12 is a right angle. Therefore, the first protruding portion 16 has a trapezoidal cross-sectional shape orthogonal to the first side surface 16b, and the width (width in a specific direction) between the first side surface 16b and the second side surface 16c is the base end side. It has a tapered shape that shortens toward the tip side.

The first angle θ1 of the first side surface 16b of the first protrusion 16 is preferably 80 ° or less, more preferably 70 ° or less, still more preferably 60 ° or less. The first angle θ1 is preferably 10 ° or more, more preferably 20 ° or more, and further preferably 30 ° or more. Further, the first side surface 16b preferably has an area larger than the area of the tip surface 16a.

When the main surface PS of the base material layer 12 has irregularities with respect to the above angle, the virtual surface orthogonal to the axial direction of the relative rotation between the polishing pad 11 and the object to be polished becomes the main surface PS as the reference of the angle. Equivalent to. The tip surface 16a of the first protrusion 16 may be inclined at an angle of, for example, within ± 5 ° depending on the state of the main surface PS of the base material layer 12 and the dimensional error of the polishing layer 13. These points are the same for the second protruding portion 17, which will be described later.

The ratio of the width H2 (width in the specific direction) of the tip surface 16a to the width H1 (width in the specific direction) of the base end portion of the first protrusion 16 in the cross section orthogonal to the first side surface 16b of the first protrusion 16. H2 / H1) is, for example, 0.5 to 0.65.

The length L1 (length in the direction along the first side surface 16b) of the first protruding portion 16 shown in FIG. 2 is not particularly limited, but is, for example, the width of the base end portion of the first protruding portion 16. It is preferably the same as or higher than H1. The ratio (L1 / H1) of the length L1 to the width H1 of the base end portion of the first protrusion 16 is, for example, 1.0 to 1.3. In the present embodiment, the first protruding portion 16 arranged in the inner region Aa has a length L1 longer than the width H1, and the first protruding portion 16 arranged in the outer region Ab has a length L1. It is about the same as the width H1.

As shown in FIG. 4, the second protruding portion 17 has a tip surface 17a parallel to the main surface PS of the base material layer 12, a first side surface 17b connected to the tip surface 17a, and a side opposite to the first side surface 17b. It has a second side surface 17c, which is a surface of the above. The first side surface 17b is a right-angled surface at which the first angle θ3 with respect to the main surface PS of the base material layer 12 is a right angle. The second side surface 17c is a right-angled surface at which the second angle θ4 with respect to the main surface PS of the base material layer 12 is a right angle.

Therefore, the second protruding portion 17 has a rectangular cross-sectional shape orthogonal to the first side surface 17b, and the width (width in a specific direction) between the first side surface 17b and the second side surface 17c is the base end side. It is the same from to the tip side. The ratio of the width H4 (width in the specific direction) of the tip surface 17a to the width H3 (width in the specific direction) of the base end portion of the second protrusion 17 in the cross section orthogonal to the first side surface 17b of the second protrusion 17 (width in the specific direction). The width H4 / H3) is 1.

The length L2 (length in the direction along the first side surface 16b) of the second protruding portion 17 shown in FIG. 2 is not particularly limited, but is, for example, the width of the base end portion of the second protruding portion 17. It is preferably the same as or higher than H3. The ratio (L2 / H3) of the length L2 to the width H3 of the base end portion of the second protruding portion 17 is, for example, 1.0 to 1.3. In this embodiment, the length L2 of the second protruding portion 17 is about the same as the width H3.

The second protruding portion 17 is formed so that the width of the tip surface in a specific direction is longer than that of the first protruding portion 16. That is, the width H4 of the tip surface 17a of the second protrusion 17 is longer than the width H2 of the tip surface 16a of the first protrusion 16. The ratio (H4 / H2) of the width H4 of the tip surface 17a of the second protrusion 17 to the width H2 of the tip surface 16a of the first protrusion 16 is, for example, 1.3 to 1.7. Further, the ratio (H3 / H1) of the width H3 of the base end portion of the second protruding portion 17 to the width H1 of the base end portion of the first protruding portion 16 is, for example, 0.9 to 1.1.

As shown in FIGS. 2 and 3, in the inner region Aa, the first protruding portion 16 has a first side surface 16b on the front side in the rotation direction, which is one side of the relative rotation direction RD between the polishing pad 11 and the object to be polished. A plurality of pieces are arranged side by side in a direction along the first side surface 16b and in a direction orthogonal to the same direction so that the (tilted surface) is located.

As shown in FIGS. 2 and 4, in the outer region Ab, the first protruding portion 16 has a direction along the first side surface 16b so that the first side surface 16b (inclined surface) is located on the front side in the rotation direction. A plurality of them are arranged side by side in the direction along the length L1). A plurality of the second protrusions 17 are arranged side by side in the direction along the first side surface 17b (direction along the length L2) so that the first side surface 17b (right angle surface) is located on the front side in the rotation direction. .. Then, the row of the first protrusions 16 arranged in the direction along the first side surface 16b and the row along the first side surface 17b so that the first protrusion 16 is located on the front side in the rotation direction of the second protrusion 17. The rows of the second protrusions 17 arranged in the direction are alternately arranged in the direction orthogonal to the row.

The outer region Ab in which the first protrusion 16 and the second protrusion 17 are arranged has a tip surface of the protrusion 15 occupying a unit area in a plan view more than the inner region Aa in which only the first protrusion 16 is arranged. The ratio of (tip surfaces 16a, 17a) is large. That is, in the outer region Ab, the contact area per unit area with respect to the object to be polished is larger than that in the inner region Aa. The above ratio of the outer region Ab is, for example, 60 to 75%. The above ratio of the inner region Aa is, for example, 25 to 40%. The ratio of the outer region Ab is, for example, 1.5 to 3 times the ratio of the inner region Aa. The ratio of the inner region Aa and the outer region Ab can be adjusted by changing the arrangement pattern of the first protruding portion 16 and the second protruding portion 17 and the shapes of the first protruding portion 16 and the second protruding portion 17. ..

<Groove of polishing pad>
As shown in FIG. 1, the grooves 18 of the polishing pad 11 include a main trunk groove 18a extending linearly from the inner peripheral end 11a of the polishing pad 11 toward the outer peripheral end 11b, and the main trunk groove 18a and the outer peripheral end 11b of the polishing pad 11. It is provided with a branch groove 18b that linearly connects and. The main trunk groove 18a and the branch groove 18b form a continuous groove 18 between the inner peripheral end 11a and the outer peripheral end 11b of the polishing pad 11.

As shown in FIGS. 3 and 4, the groove 18 of the polishing pad 11 is formed between the protrusion 15 and the protrusion 15 adjacent thereto. The groove 18 of the polishing pad 11 is composed of a first groove 18c having an inner bottom made of a polishing layer 13 and a second groove 18d having an inner bottom made of a base material layer 12. The second groove 18d is a portion formed in a portion where the polishing layer 13 and the polishing layer 13 are separated from each other, and the base material layer 12 is exposed between the protruding portion 15 and the protruding portion 15 adjacent thereto. In other words, the polishing layer 13 is composed of a plurality of polishing layers 13 arranged apart from each other on the base material layer 12, and the polishing pad 11 is configured with the base material layer 12 as an inner bottom. It has a groove 18d. In FIG. 1, the second groove 18d is shown in a satin pattern in order to distinguish the first groove 18c from the second groove 18d.

Further, the distance between the second side surface 17c of the second protrusion 17 and the first side surface 16b of the first protrusion 16 in the outer region Ab is the same as the distance between the first protrusions 16 in the inner region Aa. The distance between the second side surface 16c of the first protrusion 16 and the first side surface 17b of the second protrusion 17 in the outer region Ab is the second side surface 17c and the first protrusion of the second protrusion 17 in the outer region Ab. It is shorter than the distance from the first side surface 16b of the portion 16.

<Dimensions of polishing pad>
The diameter of the polishing pad 11 is not particularly limited, but is, for example, about 10 to 1000 mm. The dimensions of each part of the polishing pad 11 are not particularly limited, but the width (H1, H3) of the base end portion of the protruding portion 15 is about 3 to 20 mm in a plan view, and the length of the protruding portion 15 (L1, L2). ) Is about 5 to 50 mm, and the width of the groove 18 is set to about 3 to 20 mm. Further, the height of the protruding portion 15 is set to about 5 to 30 mm.

<How to use the polishing pad>
The polishing pad 11 is attached to, for example, a well-known polishing machine equipped with a rotation driving device. The surface of the object to be polished is polished by the 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 a glass plate, a stainless plate, and an aluminum plate. In such polishing, a polishing slurry containing abrasive grains is used.

FIG. 5 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. The glass plate GS as the object to be polished is fixed on the 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 portion 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 16b (inclined surface) of the first protrusion 16 in the polishing layer 13 is at the head and advances with respect to the glass plate GS. As a result, the upper surface of the glass plate GS is polished. At this time, the groove 18 of the polishing pad 11 becomes a flow path for the polishing slurry and the polishing dust, and the polishing slurry and the polishing dust are discharged from the outer peripheral end 11b of the polishing pad 11.

Next, the operation and effect of this embodiment will be described.
(1) The polishing pad 11 has a base material layer 12 and a polishing layer 13 laminated on the main surface of the base material layer 12. In the polishing layer 13, protrusions 15 having a tip surface parallel to the main surface of the base material layer 12 are arranged in a predetermined pattern, and the width of the protrusion 15 in a specific direction is gradually shortened toward the tip side. It includes a first protruding portion 16 having a tapered shape, and a second protruding portion 17 having a width in a specific direction on the tip surface longer than that of the first protruding portion 16.

According to the above configuration, as the projecting portion 15, the first projecting portion 16 and the second projecting portion 17 having different widths of the tip surfaces are provided. Therefore, even when the tip surface of the second protruding portion 17 is formed large in order to improve the efficiency of polishing, the contact area of the first protruding portion 16 with respect to the object to be polished is small, and the contact pressure due to the bending due to the tapered shape. By the presence of a portion where the value becomes smaller, excessive catching on the object to be polished is suppressed. As a result, the problem of skipping the object to be polished, which occurs when the tip surface of the protruding portion is formed to be large, is suppressed, and the polishing pad can easily improve the efficiency of polishing.

(2) The first protrusion 16 is arranged so that one side in a specific direction is located on the front side in the rotation direction, and the first side surface 16b has an acute angle with respect to the main surface of the base material layer 12 on the front side in the rotation direction. It has a (sloping surface) and has a trapezoidal cross-sectional shape orthogonal to the first side surface 16b. The second protruding portion 17 is arranged so that one side in a specific direction is located on the front side in the rotation direction, and the first side surface 17b (rectangular surface) whose angle with respect to the main surface of the base material layer 12 is orthogonal to the front side in the rotation direction. ), And the cross-sectional shape orthogonal to the first side surface 17b is rectangular.

According to the above configuration, the effect of suppressing excessive catching of the object to be polished by the first protruding portion 16 and the effect of improving the polishing efficiency by enlarging the tip surface of the second protruding portion 17 are further improved.

(3) The first protruding portion 16 and the second protruding portion 17 have a parallel four-sided shape in a plan view.
According to the above configuration, the polishing slurry easily flows between the first protruding portion 16 and the second protruding portion 17, and the polishing efficiency is improved.

(4) The polishing layer 13 includes an inner region Aa located on the inner side in the radial direction and an outer region Ab located on the outer side in the radial direction and having a contact area per unit area with respect to the object to be polished larger than the inner region Aa. .. In the inner region Aa, only the first protrusion 16 is arranged in a predetermined pattern, and in the outer region Ab, the first protrusion 16 and the second protrusion 17 are arranged in a predetermined pattern.

The second protruding portion 17 having a long tip surface can obtain high polishing efficiency, but is liable to be excessively caught on the object to be polished. By arranging the second protruding portion 17 in combination with the first protruding portion 16 only in the outer region Ab in the polishing layer 13 where the moving distance per rotation is long, the effect of improving the polishing efficiency and the suppression of excessive catching are suppressed. The effect can be compatible at a high level.

(5) The inner region Aa is a polygonal shape that is rotationally symmetric in a plan view.
According to the above configuration, when the polishing pad 11 is rotated, it is suppressed that a portion where only the outer periphery of the inner region Aa (the boundary portion between the inner region Aa and the outer region Ab) continues to pass is suppressed, and polishing unevenness is less likely to occur. Become.

(6) In the outer region Ab, the first protruding portion 16 and the second protruding portion 17 are alternately arranged so that the second protruding portion 17 is located on the front side in the rotation direction of the first protruding portion 16.
According to the above configuration, the effect of improving the polishing efficiency and the effect of suppressing excessive catching can be achieved at a high level.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-The shape of the protrusion 15 may be changed. For example, the protruding portion 15 may have a rectangular or rhombic shape in a plan view. The first protruding portion 16 may have a cross-sectional trapezoidal shape in which both the first side surface 16b and the second side surface 16c are inclined surfaces. In this case, the second angle θ2 of the first protrusion 16 may be an acute angle or an obtuse angle. The second protruding portion 17 may have a cross-sectional trapezoidal shape in which at least one of the first side surface 17b and the second side surface 17c is an inclined surface. In this case, the first angle θ3 and the second angle θ4 of the second protrusion 17 may be an acute angle or an obtuse angle.

-The arrangement of the first protruding portion 16 and the second protruding portion 17 may be changed. For example, the first protrusion 16 may be provided in the inner region Aa. In the above embodiment, the regions A1 to A6 are divided, but the present invention is not limited to this, and the number and shape of the divided regions may be changed. Further, the protrusions 15 may be uniformly arranged so as to radiate from the center of the polishing pad without providing regions such as the regions A1 to A6 in which the protrusions 15 are arranged differently. A plurality of types of first protrusions 16 having different shapes and a plurality of types of second protrusions 17 having different shapes may be arranged in combination.

In the above embodiment, the first protruding portion 16 and the second protruding portion 17 are alternately arranged so that the second protruding portion 17 is located on the front side in the rotation direction of the first protruding portion 16 in the outer region. However, two or more first protrusions 16 may be arranged between the second protrusions 17. Further, the second protrusion 17 may not be located on the front side in the rotation direction of the first protrusion 16.

-The inner region Aa may be a rotationally symmetric polygon shape other than a star-shaped polygon (for example, a regular polygon such as a regular pentagon or a regular hexagon), or a shape other than a rotationally symmetric polygon (for example, a circle or an ellipse). Shape) may be used. Further, the configuration may be such that the inner region Aa and the outer region Ab are not provided.

The base material layer 12 of the polishing pad 11 may have an elastic layer omitted.
The polishing layer 13 of the polishing pad 11 is composed of a plurality of polishing layers 13 arranged apart from each other on the base material layer 12, but may be composed of a single polishing layer 13 integrated with the polishing layer 13.

The polishing pad 11 is used by being relatively rotated so as to be counterclockwise in a plan view (FIG. 1) seen from the polishing layer 13 side, but is used by being relatively rotated so as to be clockwise. May be changed.

By including the abrasive grains in the polishing layer 13 (each protruding portion 15) of the polishing pad 11, the object to be polished may be polished using water or the like as a polishing liquid without using the 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 mounted on a polishing machine in which a plurality of polishing pads are simultaneously rotated by a planetary gear mechanism.

11 ... polishing pad, 12 ... base material layer, 13 ... polishing layer, 15 ... protrusion, 16 ... first protrusion, 16a ... tip surface, 16b ... first side surface (inclined surface), 17 ... second protrusion, 17a ... tip surface, 17b ... first side surface (right angle surface), 18 ... groove, A1 to A6 ... region, Aa ... inner region, Ab ... outer region, GS ... glass plate, PS ... main surface, RD ... relative rotation direction.

Claims (4)

A polishing pad having a base material layer and a polishing layer laminated on the main surface of the base material layer, and polishing the object to be polished by relative rotation with the object to be polished.
The polishing layer is formed by arranging protrusions having a tip surface parallel to the main surface of the base material layer in a predetermined pattern.
As the protrusion,
A tapered first protrusion whose width in a specific direction gradually shortens toward the tip side,
A second protrusion having a width in the specific direction on the tip surface longer than the first protrusion is provided.
The first protrusion is arranged so that one side in the specific direction is located on the front side in the rotation direction, and has an inclined surface having an acute angle with respect to the main surface of the base material layer on the front side in the rotation direction. The cross-sectional shape orthogonal to the inclined surface is a trapezoidal shape.
The second protruding portion is arranged so that one side in the specific direction is located on the front side in the rotation direction, and has a right-angled surface having a right angle to the main surface of the base material layer on the front side in the rotation direction. The cross-sectional shape orthogonal to the right-angled plane is rectangular,
The polishing layer includes an inner region located on the inner side in the radial direction and an outer region located on the outer side in the radial direction and having a contact area per unit area with respect to the object to be polished larger than the inner region.
In the inner region, only the first protrusion is arranged as the protrusion in a predetermined pattern.
In the outer region, the first protrusion and the second protrusion are arranged as the protrusion in a predetermined pattern.
The polishing pad is an annular shape having an outer peripheral end which is an outer peripheral edge and an inner peripheral end which is an inner peripheral edge in a plan view.
A polishing pad formed between the first protruding portion and the second protruding portion in the outer region, and provided with a groove extending from the inner peripheral end to the outer peripheral end through the inner region. The polishing pad according to claim 1 , wherein the first protruding portion and the second protruding portion have a parallel quadrilateral shape in a plan view. The polishing pad according to claim 1 or 2 , wherein the inner region has a polygonal shape that is rotationally symmetric in a plan view. The outer region is characterized in that the first protrusion and the second protrusion are alternately arranged so that the first protrusion is located on the front side in the rotation direction of the second protrusion. The polishing pad according to any one of claims 1 to 3 .

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