Polishing pads and polishing devices

Abstract

The present invention provides a polishing pad capable of stably polishing the center of the workpiece, and a polishing apparatus equipped with the polishing pad. [Solution] According to one aspect of the present invention, when the polishing surface 30A is viewed from the normal direction of the polishing surface 30A, in each polishing region R, the diameter of the first protrusion 32 is 100 μm or more and 500 μm or less, and the plurality of first protrusions 32 are arranged at predetermined intervals such that they are radial along a first direction DR1 of the polishing surface 30A centered on a reference point RF of the polishing surface 30A, and spiral along a second direction DR2 that gradually moves away from the reference point RF as it rotates around the reference point RF, and the distance D1 between the first centers is 2 to 4 times the diameter of the first protrusion 32, the distance D2 between the second centers of the first protrusions 32 is 2.5 to 5 times the diameter of the first protrusion 32, and the distance D3 is 1 / 4 to 1 time the diameter of the first protrusion 32.

Description

Technical Field

[0001] The present invention relates to a polishing pad and a polishing apparatus.

Background Art

[0002] Conventionally, for polishing a workpiece such as a semiconductor wafer, since very precise flatness is required, a chemical mechanical polishing method (CMP) using a slurry and a polishing pad has been used. CMP is a method of polishing the surface of a workpiece such as a semiconductor wafer while supplying a slurry to the polishing surface of a rotating polishing pad and pressing and rotating the workpiece.

[0003] The polishing pad used in CMP has a polishing layer formed of a synthetic resin such as polyurethane, and concentric or lattice-shaped grooves for supplying and discharging the polishing slurry during polishing are formed on the surface of the polishing layer.

[0004] In recent years, due to the miniaturization of wirings in semiconductor devices and the like, further precise polishing has been demanded, and the unevenness on the surface of the polishing layer has also been required to be further miniaturized. For this reason, a polishing pad (for example, see Patent Document 1) in which a predetermined convex pattern is formed on the surface using a gravure, and the change in diameter is small even when the convex portion wears as polishing progresses, and it is relatively easy to maintain the surface pressure of the polishing point, a polishing pad (for example, see Patent Document 2) in which a hexagonal or arcuate convex pattern is formed, and a polishing pad (for example, see Patent Document 3) in which a C-shaped or U-shaped convex pattern is formed have been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] However, when polishing an object using a polishing pad having a convex pattern as shown in Patent Documents 1 to 3, there is a problem in that the polishing rate at the center of the object is not stable.

[0007] This invention was made to solve the above problems. Specifically, the objective is to provide a polishing pad that can stably polish even the center of the workpiece, and a polishing apparatus equipped with the polishing pad. [Means for solving the problem]

[0008] [1] A polishing pad comprising a polishing layer having a polishing surface for polishing an object to be polished, wherein the polishing surface has a plurality of polishing regions divided concentrically around an arbitrary point on the polishing surface, and a plurality of first protrusions provided within each polishing region, and when the polishing surface is viewed in plan from the direction normal to the polishing surface, the diameter of each first protrusion in each polishing region is 100 μm or more and 500 μm or less, and the plurality of first protrusions are arranged at predetermined intervals so as a whole they are radial along a first direction which is the radial direction of the polishing surface, centered on the reference point of the polishing surface, and spiral along a second direction which gradually moves away from the reference point as the polishing surface rotates around the reference point, in the first direction A polishing pad wherein the distance between the first centers of two adjacent first protrusions is between 2 and 4 times the diameter of the first protrusion, the distance between the second centers of two adjacent first protrusions in the second direction is between 2.5 and 5 times the diameter of the first protrusion, and in two adjacent first protrusions in the second direction, when the first protrusion closer to the reference point on the polishing surface is designated as the first protrusion (A), and the first protrusion further from the reference point on the polishing surface than the first protrusion (A) is designated as the first protrusion (B), the distance from the intersection of a virtual circle centered on the reference point on the polishing surface and passing through the center of the first protrusion (A), and a virtual line connecting the reference point on the polishing surface and the center of the first protrusion (B), to the center of the first protrusion (B), is between 1 / 4 and 1 times the diameter of the first protrusion.

[0009] [2] The polishing pad according to [1] above, wherein the width of each polishing region is an integer multiple of the first intercenter distance.

[0010] [3] The polishing pad according to [1] or [2] above, wherein the width of the polishing region closer to the reference point than the outer periphery of the polishing surface is narrower than the width of the polishing region located on the outer periphery of the polishing surface.

[0011] [4] In two adjacent polishing regions, when the polishing region closer to the reference point of the polishing surface is defined as polishing region (R1) and the polishing region further from the reference point of the polishing surface than polishing region (R1) is defined as polishing region (R2), the polishing surface further has a second protrusion at the boundary between polishing region (R1) and polishing region (R2), the second protrusion having a diameter of 100 μm or more and 500 μm or less for adjusting the distance between the first protrusion located on the outermost side of polishing region (R1) and the first protrusion located on the innermost side of polishing region (R2), the polishing pad according to any one of the above [1] to [3].

[0012] [5] In two adjacent polishing regions, the polishing region closer to the reference point on the polishing surface is designated as polishing region (R1), and the polishing region further from the reference point on the polishing surface than polishing region (R1) is designated as polishing region (R2), and the plurality of first protrusions that form a radial pattern and are arranged in a line in the radial direction are designated as a linear first protrusion group, wherein the polishing region (R2) has more linear first protrusion groups than the polishing region (R1), the polishing pad according to any one of the above [1] to [4].

[0013] [6] The polishing pad according to any one of the above [1] to [5], wherein in each polishing region, the plurality of first protrusions are arranged to form a plurality of spirals in the second direction.

[0014] [7] A polishing device comprising a polishing pad as described in any one of the above items [1] through [6]. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a polishing pad that can stably polish even the central part of the workpiece, and a polishing apparatus equipped with the polishing pad. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram of the polishing pad according to the embodiment. [Figure 2] FIG. 2 is a schematic configuration diagram of another polishing pad according to an embodiment. [Figure 3] FIG. 3 is a plan view showing a polishing region of a polishing surface according to an embodiment. [Figure 4] FIG. 4 is a plan view showing an arrangement pattern of the first convex portions and the second convex portions in a partial polishing region of a polishing surface according to an embodiment. [Figure 5] FIG. 5 is a diagram showing center distances D1 and D2 of the first convex portions on a polishing surface according to an embodiment. [Figure 6] FIG. 6 is a diagram showing a distance D3 on a polishing surface according to an embodiment. [Figure 7] FIG. 7 is a diagram showing a linear first convex portion group and a spiral first convex portion group on a polishing surface according to an embodiment. [Figure 8] FIGS. 8A to 8C are diagrams showing a manufacturing process of a polishing layer according to an embodiment. [Figure 9] FIGS. 9A and 9B are diagrams showing a manufacturing process of a polishing layer according to an embodiment. [Figure 10] FIG. 10 is a schematic configuration diagram of a polishing apparatus including a polishing pad according to an embodiment. [Figure 11] FIG. 11 is a diagram showing the relationship between a workpiece to be polished and a polishing surface during polishing of the workpiece.

MODE FOR CARRYING OUT THE INVENTION

[0017] The polishing pad and polishing apparatus according to embodiments of the present invention will be described below. Figure 1 is a schematic configuration diagram of the polishing pad according to this embodiment, Figure 2 is a schematic configuration diagram of another polishing pad according to this embodiment, Figure 3 is a plan view showing the polishing area of ​​the polishing surface according to this embodiment, Figure 4 is a plan view showing the arrangement pattern of the first and second protrusions in a part of the polishing area of ​​the polishing surface according to this embodiment, Figure 5 is a diagram showing the distances D1 and D2 between the centers of the first protrusions on the polishing surface according to this embodiment, Figure 6 is a diagram showing the distance D3 on the polishing surface according to this embodiment, Figure 7 is a diagram showing the linear first protrusion group and the spiral first protrusion group on the polishing surface according to this embodiment, Figures 8A to 8C, Figure 9A and Figure 9B are diagrams showing the manufacturing process of the polishing layer according to this embodiment. Figure 10 is a schematic configuration diagram of a polishing apparatus equipped with the polishing pad according to this embodiment, and Figure 11 is a diagram showing the relationship between the workpiece and the polishing surface when polishing the workpiece.

[0018] <<<Polishing pad>>> As shown in Figure 1, the polishing pad 10 is, for example, circular in shape and comprises a base material 20, a polishing layer 30, a cushion layer 40, and an adhesive layer 50 for bonding the base material 20 and the cushion layer 40. The polishing layer 30 is provided on the base material 20. The polishing pad 10 comprises a base material 20, a cushion layer 40, and an adhesive layer 50, but it is sufficient to have the polishing layer 30, and it is not necessary to have the base material 20, cushion layer 40, and adhesive layer 50.

[0019] <<Base material>> The base material 20 is not particularly limited, but examples include resin-impregnated nonwoven fabric, sponge-like resin foam, and resin film. Examples of the resin include polyurethane resin, polyester resin, and polyolefin resin.

[0020] The base material 20 is not particularly limited as long as it is capable of forming the resin described later on its upper surface. Among these, resin-impregnated nonwoven fabrics and sponge-like resin foams are preferred from the viewpoint of chemical resistance, heat resistance, and cost-effectiveness.

[0021] <<Polishing layer>> The polishing layer 30 has a base portion 31, a plurality of first protrusions 32 provided on the base portion 31, and a plurality of second protrusions 33 provided on the base portion 31. The polishing layer 30 does not need to have a base portion 31 or second protrusions 33, as long as it has the first protrusions 32. For example, as shown in the polishing pad 60 in Figure 2, the polishing layer 30 may have a configuration in which the first protrusions 32 and second protrusions 33 are provided directly on the substrate 20 without the base portion 31.

[0022] As shown in Figures 1 and 2, the polishing layer 30 has a polishing surface 30A that comes into contact with the workpiece when polishing it. The polishing surface 30A constitutes the surface 10A of the polishing pad 10. As shown in Figure 3, the polishing surface 30A has multiple polishing regions R divided into concentric circles.

[0023] Within each polishing region R, multiple first protrusions 32 are provided, as shown in Figures 1 and 4. Additionally, some areas of the polishing region R have second protrusions. In Figure 4, for convenience, the first protrusions 32 are depicted in gray and the second protrusions 33 in black to clearly distinguish them from the second protrusions 33.

[0024] The portions of the polishing surface 30A that do not have the first protrusion 32 and the second protrusion 33, that is, the portions between the first protrusion 32 and between the first protrusion 32 and the second protrusion 33, may be grooves. The presence of such grooves makes it easier for slurry to be supplied to the polishing surface and for polishing debris to be discharged.

[0025] The polishing surface 30A shown in Figure 3 is circular, but the shape of the polishing surface 30A is not particularly limited. The size of the polishing surface 30A depends on the size of the workpiece to be polished, but the diameter of the polishing surface 30A may be between 50 mm and 2000 mm.

[0026] <Polishing area> Each polishing region R is divided concentrically around the center of the reference point RF (see Figure 3) on the polishing surface 30A, when an arbitrary point on the polishing surface 30A in a plan view from the normal direction of the polishing surface 30A is defined as the reference point RF. By dividing the polishing surface 30A into multiple polishing regions R in this way, the second intercenter distance D2, described later, can be made to be between 2.5 and 5 times the diameter of the first protrusion 32.

[0027] In the polished surface 30A shown in Figure 3, the reference point RF is at the center of the polished surface 30A, but the reference point RF does not have to be at the center of the polished surface 30A. In this specification, "polishing region" means the region of the polished surface that comes into contact with the workpiece during polishing. That is, the region of the polished surface that does not come into contact with the workpiece during polishing is not included in the polishing region. For example, the portion of the polished surface 30A shown in Figure 1 that is close to the reference point RF does not come into contact with the workpiece during polishing, and is therefore not included in the polishing region. The number of polishing regions R depends on the size of the polished surface 30A and the size of the workpiece, but may be, for example, 2 to 30, or 5 to 25, preferably 7 to 20.

[0028] It is preferable that the width of the polishing region R closer to the reference point RF is narrower than the width of the polishing region R located on the outer periphery of the polishing surface 30A. By narrowing the width of the polishing region R closer to the reference point RF compared to the width of the polishing region R located on the outer periphery, it becomes easier to set the second center distance D2, described later, to 2.5 times or more and 5 times or less the diameter of the first protrusion 32.

[0029] The width of each polishing region R is preferably an integer multiple of the first center-to-center distance D1 of the first protrusions 32, which will be described later. This prevents the distance between the first protrusion 32 located on the outermost side of polishing region R1 and the first protrusion 32 located on the innermost side of polishing region R2 from becoming too large when two adjacent polishing regions R1 and R2 are polishing region R1, and polishing region R located on the side further from the reference point RF of the polishing surface 30A than polishing region R1. The width of each polishing region R is more preferably 10 to 100 times, or 20 to 75 times, the first center-to-center distance D1 of the first protrusions 32.

[0030] The width of each polishing area R is not particularly limited, but is preferably 3 mm or more and 500 mm or less. If the width of each polishing area R is 3 mm or more, a sufficient number of first protrusions 32 can be placed within each polishing area R. If the width is 500 mm or less, the distance D2 between the second centers of two adjacent first protrusions 32 located near the inner boundary in each polishing area R will not become too narrow, and the distance D2 between the second centers of two adjacent first protrusions 32 located near the outer boundary in the second direction DR2 will not become too wide. The lower limit of the width of each polishing area R is more preferably 4 mm or more, 7 mm or more, or 10 mm or more, and the upper limit is more preferably 400 mm or less, 250 mm or less, or 100 mm or less. The width of each polishing area R may be, for example, 4 mm or more and 400 nm or less, 7 mm or more and 250 mm or less, or 10 mm or more and 100 mm or less.

[0031] <First protrusion> The shape of the first protrusion 32 can be a columnar shape such as a cylindrical shape, an elliptical columnar shape, or a polygonal columnar shape, or a frustoconical shape such as a frustoconical shape, an elliptical frustoconical shape, or a polygonal frustoconical shape. Among these, a cylindrical shape is preferred because the area of ​​the first protrusion 32 that contacts the workpiece does not change much even as the polishing of the workpiece progresses.

[0032] When the polished surface 30A is viewed from the normal direction of the polished surface 30A, the diameter of the first protrusion 32 in each polished region R is between 100 μm and 500 μm. By adjusting the diameter of the first protrusion 32 to the above range, the polishing rate and surface quality tend to improve. The upper limit of the diameter of the first protrusion 32 is preferably 125 μm or more, 150 μm or more, or 175 μm or more, and the lower limit is preferably 450 μm or less, 400 μm or less, or 350 μm or less. For example, the diameter of the first protrusion 32 may be between 125 μm and 450 μm, between 150 μm and 400 μm, or between 175 μm and 350 μm. It is preferable that the diameter of the first protrusion 32 is all approximately constant. Therefore, it is preferable that the standard deviation of the diameter of the first protrusion 32 is 50 μm or less.

[0033] When the polishing surface 30A is viewed from the normal direction of the polishing surface 30A, the multiple first protrusions 32 in each polishing region R are arranged at predetermined intervals so as a whole they are radial along the first direction DR1, which is the radial direction of the polishing surface 30A, centered on the reference point RF of the polishing surface, and spiral along the second direction DR2, which rotates around the reference point RF of the polishing surface 30A and gradually moves away from the reference point RF (see Figure 5). That is, in each polishing region R, the first protrusions 32 that form a radial pattern in the first direction DR1 also form a spiral pattern in the second direction DR2. The second direction DR2 may be either a clockwise or counterclockwise rotation.

[0034] When the polishing surface 30A is viewed from the normal direction of the polishing surface 30A, in each polishing region R, the distance D1 (see Figure 5) between the first centers of two adjacent first protrusions 32 in the first direction DR is between 2 and 4 times the diameter of the first protrusion 32. If the distance D1 between the first centers is 2 times or more the diameter of the first protrusion 32, the two adjacent first protrusions 32 in the first direction DR1 are not too close together, so it is possible to prevent the first protrusions 32 from becoming densely packed even in the part close to the reference point RF in each polishing region R. Also, if it is 4 times or less, the two adjacent first protrusions 32 in the first direction DR1 are not too far apart, so it is possible to keep the number of first protrusions 32 in contact with the workpiece to be polished relatively constant. The lower limit of the first center-to-center distance D1 may be 2.2 times or more, 2.4 times or more, or 2.6 times or more the diameter of the first protrusion 32, and the upper limit may be 3.8 times or less, 3.6 times or less, or 3.4 times or less the diameter of the first protrusion 32. For example, the first center-to-center distance D1 may be 2.2 times or more and 3.8 times or less, 2.4 times or more and 3.6 times or less, or 2.6 times or more and 3.4 times or less the diameter of the first protrusion 32. In this specification, "first center-to-center distance" means the shortest distance between the centers of two adjacent first protrusions when the polished surface is viewed in plan from the direction normal to the polished surface.

[0035] When the polishing surface 30A is viewed from the normal direction of the polishing surface 30A, in each polishing region R, the distance D2 between the second centers of two adjacent first protrusions 32 in the second direction DR2 (see Figure 5) is between 2.5 and 5 times the diameter of the first protrusion 32. If the distance D2 between the second centers is 2.5 times or more the diameter of the first protrusion 32, the two adjacent first protrusions 32 in the second direction DR2 are not too close together, so it is possible to prevent the first protrusions 32 from becoming densely packed even in the part close to the reference point RF in each polishing region R. Also, if it is 5 times or less, the two adjacent first protrusions 32 in the second direction DR2 are not too far apart, so it is possible to keep the number of first protrusions 32 in contact with the workpiece to be polished relatively constant. The lower limit of the second center distance D2 may be 2.8 times or more, 3.0 times or more, or 3.2 times or more the diameter of the first protrusion 32, and the upper limit may be 4.8 times or less, 4.6 times or less, or 4.4 times or less the diameter of the first protrusion 32. For example, the second center distance D2 may be 2.8 times or more and 4.8 times or less, 2.6 times or more and 4.6 times or less, or 2.8 times or more and 4.4 times or less the diameter of the first protrusion 32. In this specification, "second center distance" means the shortest distance between the centers of two adjacent first protrusions when the polished surface is viewed from the normal direction of the polished surface in a plan view.

[0036] Here, the first protrusions 32 are arranged at predetermined intervals so as a whole they radiate along the first direction DR1 and spiral in the second direction DR2. However, as the polishing surface 30A moves away from the reference point RF, the distance D2 between the second centers of the first protrusions widens, so there is a risk that this distance D2 will not be between 2.5 and 5 times the diameter of the first protrusions 32. For this reason, the polishing area R is divided into multiple polishing areas R, and the number of linear first protrusion groups 32C (see Figure 7), described later, within the polishing area R is increased as the distance from the reference point RF increases, thereby adjusting so that the distance D2 between the second centers falls within the above range for each polishing area R.

[0037] Furthermore, in the polishing region R close to the reference point RF of the polishing surface 30A, the number of linear first convex portions 32C that can be placed is less than in the polishing region R on the outer periphery. Therefore, as the distance from the reference point RF of the polishing surface 30A increases, the second center-to-center distance D2 may fall outside the above range. For this reason, the width of the polishing region R closer to the reference point RF than the outer periphery of the polishing surface 30A is made narrower than the width of the polishing region 3 located on the outer periphery of the polishing surface 30A, so that the second center-to-center distance D2 remains within the above range at any point within the polishing region R closer to the reference point RF than the outer periphery of the polishing surface 30A.

[0038] In the second direction DR2, when two adjacent first protrusions 32 are defined as follows: the first protrusion 32 closer to the reference point RF of the polished surface 30A is designated as the first protrusion 32A (first protrusion (A)), and the first protrusion 32 further from the reference point RF of the polished surface 30A than the first protrusion 32A is designated as the first protrusion 32B (first protrusion (B)), the distance D3 (see Figure 6) from the intersection point IP of the virtual circle VC passing through the center C1 of the first protrusion 32A, centered on the reference point RF of the polished surface 30A, and the virtual line VL connecting the reference point RF of the polished surface 30A and the center C2 of the first protrusion 32B, to the center C2 of the first protrusion 32B is between 1 / 4 and 1 times the diameter of the first protrusion 32. This means that if this distance D3 is too close or too far, the center of the workpiece does not come into contact with the first protrusion 32A during polishing, and therefore may not come into contact with the first protrusion 32B either. However, if the distance D3 is between 1 / 4 and 1 times the diameter of the first protrusion 32, then even if the center of the workpiece does not come into contact with the first protrusion 32A during polishing, it can still come into contact with the first protrusion 32B. Distance D3 represents the degree to which it deviates from the virtual circle VC. In other words, it indicates how far the first protrusions 32 are arranged in a spiral pattern from the reference point RF.

[0039] The lower limit of the distance D3 may be 1 / 3.5 times or more, 1 / 3 times or more, or 1 / 2.5 times or more the diameter of the first protrusion 32, and the upper limit may be 4 / 5 times or less, 3 / 4 times or less, or 2 / 3 times or less the diameter of the first protrusion. For example, the distance D3 may be 1 / 3.5 times or more and 4 / 5 times or less, 1 / 3 times or more and 3 / 4 times or less, or 1 / 2.5 times or more and 2 / 3 times or less the diameter of the first protrusion 32.

[0040] As shown in Figure 7, in two adjacent polishing regions R1 and R2 among a plurality of polishing regions R, the polishing region R closer to the reference point RF of the polishing surface 30A is designated as polishing region R1 (polishing region (R1)), and the polishing region R further from the reference point RF of the polishing surface 30A than polishing region R1 is designated as polishing region R2 (polishing region (R2)), forming a radial arrangement, and when a plurality of first protrusions 32 arranged in a line in the radial direction of the polishing surface 30A are designated as a linear first protrusion group 32C, it is preferable that the polishing region R2 has more linear first protrusion groups 32C than the polishing region R1. To ensure more stable polishing of the central part of the workpiece, it is essential that the distance D3 between adjacent linear first protrusions in the second direction DR2 within each polishing region R be between 1 / 4 and 1 times the diameter of the first protrusion 32. However, the distance D3 between adjacent first protrusions 32 in the second direction DR2 increases as the distance from the reference point RF of the polishing surface 30A increases. Therefore, if the distance between adjacent first protrusions 32 in the second direction DR2 falls outside the above range, it is preferable to add a group of linear first protrusions 32C between the first protrusions 32 in the second direction DR2 to bring it within the above range. As described above, the maximum distance between adjacent first protrusions 32 in the second direction DR2 increases as the distance from the reference point RF of the polishing surface 30A increases, so it is preferable that the polishing region R2, which is further from the reference point RF of the polishing surface than polishing region R1, has a larger number of linear first protrusions 32C. The number of linear first protrusions 32C in each polishing region R is not particularly limited, but is preferably between 10 and 5000.

[0041] As shown in Figure 7, in each polishing region R, when a plurality of first protrusions 32 arranged in a row to form a spiral in the second direction DR2 are called a spiral-shaped first protrusion group 32D, it is preferable that a plurality of spiral-shaped first protrusion groups 32D are arranged. The number of spiral-shaped first protrusion groups 32D in each polishing region R is not particularly limited, but for example, it is preferable that there are 10 or more and 5000 or less.

[0042] <Second protrusion> The second protrusion 33 is for adjusting the distance between the first protrusions 32. Specifically, since the polishing surface 30A is divided into multiple polishing regions R, the distance between the first protrusions 32 may become too large at the boundary between the inner polishing region R1, which is close to the reference point RF of the polishing surface 30A, and the outer polishing region R2, which is adjacent to this polishing region. For this reason, it is preferable to provide the second protrusion 33 to adjust the distance between the first protrusions 32 shown in Figures 4 and 7.

[0043] Specifically, in the two adjacent polishing regions R1 and R2 shown in Figure 7, the second protrusion 33 is positioned at the boundary between polishing region R1 and polishing region R2. By positioning the second protrusion 33, the distance between the first protrusion 32 located on the outermost side of polishing region R1 and the first protrusion 32 located on the innermost side of polishing region R2 can be adjusted.

[0044] The shape, diameter, and material of the second protrusion 33 are preferably the same as those of the first protrusion 32. This is because, when polishing the workpiece, not only the first protrusion 32 but also the second protrusion 33 comes into contact with the workpiece, thus preventing any difference in polishing between the first protrusion 32 and the second protrusion 33.

[0045] The Shore D hardness of the polishing layer 30 is not particularly limited, but is preferably between 20 and 80. If the Shore D hardness is 20 or higher, minor irregularities can be flattened, and if the Shore D hardness is 80 or lower, the occurrence of scratches on the workpiece can be reduced. The lower limit of the Shore D hardness of the polishing layer is more preferably 25 or higher, 30 or higher, or 35 or higher, and the upper limit is more preferably 75 or lower, 70 or lower, or 65 or lower. The Shore D hardness of the polishing layer shall be measured using a D-type hardness tester in accordance with Japanese Industrial Standards (JIS K 6253-1 and 6253-3:2012).

[0046] <Materials for the polished layer> The polishing layer 30 may be composed of a resin. For example, the polishing layer 30 may be a cured product of a thermosetting composition or a photocurable composition. The polishing layer 30 contains a resin and may contain other additives as needed.

[0047] The resin constituting the polishing layer 30 is not particularly limited, but examples include polyurethane resins such as polyurethane, polyurethane polyurea, polyurethane acrylate, and addition polymers of amide compounds and isocyanate compounds having ether or ester bonds in the molecule; epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, and cresol novolac type epoxy resin; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; unsaturated polyester resins; polyamide resins such as polyetheramide, polyether esteramide, and ammonium salt type tertiary nitrogen atom-containing polyamide; acrylic resins such as polyacrylate and polyacrylonitrile; vinyl resins such as polyvinyl chloride, polyvinyl acetate, and polyvinylidene fluoride; polysulfone resins such as polysulfone and polyethersulfone; acylated cellulose resins such as acetylated cellulose and butyrylated cellulose; and polystyrene resins. The resin constituting the polishing layer may be used alone or in combination of two or more types.

[0048] Among these, epoxy resins, unsaturated polyester resins, polyamide resins, and polyurethane resins are preferred. Using such resins tends to further improve the polishing rate.

[0049] Furthermore, when preparing polyurethane resins, the raw materials preferably contain polyisocyanate and polyol, and may also contain a urethane prepolymer formed by the reaction of polyisocyanate and polyol. Additionally, the raw materials may contain a curing agent as needed. This tends to further improve the polishing rate and surface quality.

[0050] The constituent units derived from polyisocyanates are not particularly limited, but examples include constituent units derived from alicyclic isocyanates, aliphatic isocyanates, and aromatic isocyanates. Among these, aromatic isocyanates are preferred, and diphenylmethane-4,4'-diisocyanate (MDI) is more preferred.

[0051] Alicyclic isocyanates are not particularly limited, but examples include 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, and isophorone diisocyanate.

[0052] Aliphatic isocyanates are not particularly limited, but examples include hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), tetramethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, trimethylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0053] Aromatic isocyanates are not particularly limited, but examples include phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), xylylene diisocyanate, naphthalene diisocyanate, and diphenylmethane-4,4'-diisocyanate (MDI).

[0054] The constituent units derived from polyols are not particularly limited, but examples include low molecular weight polyols with a molecular weight of less than 300 and high molecular weight polyols with a molecular weight of 300 or more. Among these, it is preferable to use at least low molecular weight polyols, and it is preferable to use low molecular weight polyols and high molecular weight polyols in combination.

[0055] Low molecular weight polyols are not particularly limited, but examples include low molecular weight polyols having two hydroxyl groups, such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 33-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 32,4-trimethyl-1,3-pentanediol, tricyclodecanedimethanol, and 1,4-cyclohexanedimethanol; and low molecular weight polyols having three or more hydroxyl groups, such as glycerin, hexanetriol, trimethylolpropane, isocyanuric acid, and erythritol. Low molecular weight polyols may be used individually or in combination of two or more.

[0056] Furthermore, while the polymer polyol is not particularly limited, examples include polyether polyols, polyester polyols, polycarbonate polyols, polyether polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. The polymer polyol may be used alone or in combination of two or more types.

[0057] The number-average molecular weight of the polymer polyol is preferably 300 to 1200, more preferably 400 to 950, and even more preferably 500 to 800. By using such a polymer polyol, it tends to be easier to adjust the dynamic viscoelastic properties and D hardness within the above range.

[0058] <<Manufacturing method for polishing pads>> The polishing pad can be manufactured as follows. The manufacturing method of the polishing pad according to this embodiment comprises a pouring step of pouring a curable composition into a mold having a plurality of recesses, and a curing step of curing the curable composition poured into the mold to obtain a polishing layer.

[0059] First, a metal mold 71 is prepared as shown in Figure 8A. By using a metal mold 71, the angle between the sides of the first protrusion 32 and the second protrusion 33 and the surface of the base 31 can be made approximately 90°. Alternatively, a resin mold may be used instead of the metal mold 71. The mold 71 has a shape with multiple uneven patterns that correspond to the shape of the polished surface 30A.

[0060] After preparing the mold 71, the curable composition 72 is poured into the uneven pattern of the mold 71. The method for bringing the curable composition into contact with the uneven pattern formed on the mold 71 is not particularly limited as long as the curable composition is filled (poured) into the recesses of the mold 71. Examples include gravity casting, in which the curable composition is poured into the recesses by its own weight at room temperature and pressure, and vacuum casting, in which the mold and resin are placed in a vacuum container, the pressure is reduced, and the composition is poured into the recesses at atmospheric pressure.

[0061] Furthermore, after bringing the uneven pattern formed on the mold 71 into contact with the curable composition 72, and before curing the curable composition 72, the process may further include a step of joining the base material 20 to the side of the curable composition 72 opposite to the side in contact with the mold. By using the base material 20, the curable composition 72 is cured while sandwiched between the base material 20 and the mold 71. This improves the uniformity of the thickness of the resulting cured product, and also tends to improve the flatness of the back surface (the side opposite to the side in contact with the mold 71) of the resulting cured product.

[0062] Furthermore, the positional relationship between the base material 20 and the mold 71 may be such that the base material 20 does not come into contact with the uneven pattern of the mold 71, as shown in Figure 8B, or it may be such that the base material 20 comes into contact with the uneven pattern of the mold 71, as shown in Figure 9A. If the base material 20 does not come into contact with the uneven pattern of the mold 71, the resulting polished layer 30 will have a first protrusion 32 and a second protrusion 33 that constitute the uneven pattern, and a base portion 31 for connecting the first protrusion 32 and the second protrusion 33. If the base material 20 comes into contact with the uneven pattern of the mold 71, the resulting polished layer 30 will have a first protrusion 32 and a second protrusion 33 that constitute the uneven pattern, and the first protrusion 32 and the second protrusion 33 will be formed directly on the base material 20.

[0063] After pouring the curable composition 72 into the mold 71, the curable composition 72 poured into the mold 71 is cured to obtain a polished layer 30. By curing the curable composition 72 in contact with the uneven pattern formed on the obtained mold 71, a polished layer 30, which is a cured product of the curable composition 72 with the uneven pattern transferred to it, can be obtained.

[0064] The curable composition 72 is not particularly limited, but examples include thermosetting resins; UV-curable resins; photocurable compositions containing a photopolymerization initiator and a polymerizable compound; thermosetting compositions containing a thermal polymerization initiator and a polymerizable compound; and curable compositions containing a two-component curable resin. The curable composition may also optionally contain a crosslinking agent having two or more polymerizable functional groups.

[0065] The polymerizable compounds mentioned above are not particularly limited, but examples include unsaturated carboxylic acids having polymerizable unsaturated groups such as (meth)acrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid; unsaturated carboxylic acid esters having polymerizable unsaturated groups such as (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate; polyesters having unsaturated groups; polyethers having polymerizable unsaturated groups; polyamides having polymerizable unsaturated groups; urethanes having polymerizable unsaturated groups; and aromatic compounds having polymerizable unsaturated groups such as styrene.

[0066] The above-mentioned photopolymerization initiators are not particularly limited, but examples include benzophenone compounds, acetophenone compounds, and thiothisanthone compounds. The thermal polymerization initiators are not particularly limited, but examples include azo compounds such as 32'-azobisbutyronitrile; and peroxides such as methyl ethyl ketone peroxide and benzoyl peroxide (BPO).

[0067] The thermosetting resin is not particularly limited, but examples include phenolic resins, epoxy resins, acrylic resins, urethane resins, and formaldehyde resins.

[0068] While not particularly limited, the UV-curable resin is preferably a prepolymer with a number-average molecular weight of approximately 1,000 to 10,000. Examples of materials include acrylic (methacrylic) ester resins, urethane-modified resins thereof, and thiocol resins. Reactive diluents and organic solvents can be used as appropriate depending on the application.

[0069] Furthermore, the two-component curing resin is not particularly limited, but for example, prepolymers with different physical properties can be used, such as epoxy resins, unsaturated polyester resins, and polyamide resins.

[0070] Among these, those that cure at room temperature are preferred, considering the heat resistance of the mold. Such curable compositions are not particularly limited, but examples include curable compositions containing polymerization initiators that act at room temperature, UV-curable resins and photocurable compositions that cure by light irradiation, and mixed-type curable compositions that cure by mixing two components.

[0071] The method for curing the curable composition is not particularly limited as long as it is suitable for each curable composition, but examples include photocuring methods using ultraviolet light, thermal curing methods using heat (including methods of leaving it at room temperature), or methods of mixing and leaving it, such as for two-component mixtures.

[0072] After forming the polishing layer 30, the hardened polishing layer 30 is peeled off the mold 71 as shown in Figures 8C and 9B to obtain the polishing layer 30. The obtained polishing layer 30 has an uneven pattern transferred from the mold 71, and this uneven pattern becomes the polishing surface 30A for polishing the workpiece. By this method, in this embodiment, a polishing pad with an uneven pattern of sufficient height can be manufactured at a lower cost and in a simpler manner without going through a cutting process.

[0073] <<<Polishing equipment>>> The polishing pad 10 is used by being incorporated into a polishing device. The polishing device 80 shown in Figure 10 is a chemical mechanical polishing device. The polishing device 80 comprises the polishing pad 10, a polishing platen 81 to which the polishing pad 10 is attached by double-sided tape (not shown) or the like provided on the cushion layer 40 of the polishing pad 10, a holding platen 82 for holding the workpiece 90, and a slurry supply unit 83 for supplying slurry when polishing the workpiece 90. The polishing pad 10 rotates together with the polishing platen 81 with the workpiece 90 pressed against the surface 10A (polishing surface 30A) of the polishing pad 10, polishing the workpiece 90. At that time, slurry is supplied between the polishing pad 10 and the workpiece 90 from the slurry supply unit 93. The slurry is a mixture (dispersion) of water and various chemical components and hard, fine abrasive particles, and the polishing effect is increased by the relative motion with the workpiece 90 as the chemical components and abrasive particles in the slurry flow through it. The slurry is supplied to the polishing surface 11A through grooves or holes (not shown) provided in the polishing layer 30 and then discharged.

[0074] The workpiece to be polished is not particularly limited, but examples include materials for semiconductor devices and electronic components, particularly Si substrates (silicon wafers), SiC (silicon carbide) substrates, GaAs (gallium arsenide) substrates, glass, and thin substrates (workpieces to be polished) such as hard disks and LCD (liquid crystal display) substrates. Among these, the method for manufacturing polished products of this embodiment can be suitably used as a method for manufacturing difficult-to-machine materials that are difficult to polish, such as sapphire, SiC, GaN, and diamond, which can be applied to power devices, LEDs, etc. Among these, semiconductor wafers are preferred from the viewpoint of making more effective use of the effects of the polishing pad of this embodiment, and SiC substrates, sapphire substrates, or GaN substrates are preferred. As for the material, difficult-to-machine materials such as SiC single crystals and GaN single crystals are preferred, but single crystals of sapphire, silicon nitride, or aluminum nitride may also be used.

[0075] When polishing an object with a polishing pad while rotating a polishing pad equipped with a polishing pad having a polishing layer with protrusions uniformly arranged vertically and horizontally on the object to be polished and the polishing surface, the central part of the object cannot be polished stably for the following reasons. First, as shown in Figure 11, parts of the object to be polished 90 other than the central part 90A (for example, the outer circumference of the object to be polished) move with the rotation of the object to be polished 90 and come into contact with various protrusions on the polishing surface 100A of the polishing layer 100. However, as shown in the trajectory 90B of the central part 90A of the object to be polished (see Figure 11), the central part 90A of the object to be polished moves only a small distance even with the rotation of the object to be polished 90. For this reason, the central part 90A of the object to be polished only comes into contact with specific protrusions, and for example, if there are protrusions on these specific protrusions that do not come into contact with the central part 90A, then parts of the central part 90A of the object to be polished will be left unpolished or insufficiently polished, resulting in an unstable polishing rate for the central part 90A. In contrast, according to this embodiment, when the polished surface 30A is viewed from the normal direction of the polished surface 30A, in each polished region R, the diameter of the first protrusion 32 is 100 μm or more and 500 μm or less, and the multiple first protrusions 32 as a whole are arranged radially along the first direction DR1 of the polished surface 30A centered on the reference point RF of the polished surface 30A, and spiral along the second direction DR2 which gradually moves away from the reference point RF as it rotates around the reference point RF. The protrusions are arranged at predetermined intervals to form a shape, and the distance D1 between the first centers is between 2 and 4 times the diameter of the first protrusion 32, the distance D2 between the second centers of the first protrusion 32 is between 2.5 and 5 times the diameter of the first protrusion 32, and the distance D3 is between 1 / 4 and 1 time the diameter of the first protrusion 32. As a result, even the central part 90A of the workpiece 90, which has little movement, can be brought into contact with various first protrusions 32 or the first protrusions 32 and the second protrusions 33. This ensures that the first protrusion 32 or the first protrusions 32 and the second protrusions 33 can always be brought into contact with the central part 90A of the workpiece 90, allowing for stable polishing not only in parts other than the central part 90A of the workpiece 90, but also in the central part 90A of the workpiece 90. [Examples]

[0076] To illustrate the present invention in detail, examples are given below, but the present invention is not limited to these examples.

[0077] <Example 1> A mold was prepared having a pattern of irregularities corresponding to the shapes of the first and second protrusions. A resin composition consisting of diphenylmethane-4,4'-diisocyanate (MDI), a polyester polyol composed of ethylene glycol and adipic acid ester, and trimethylolpropane was poured into this mold, mixed using a one-shot method, and cured to obtain the circular polished layer of Example 1. The one-shot method is a method in which the raw materials of the resin constituting the polished layer are added and reacted simultaneously. The D hardness of the polished layers in Example 1 and Comparative Examples 1 and 2 described later was 53, and the diameter of the polished layers was 740 mm in all cases.

[0078] The polishing layer of Example 1 had a plurality of polishing regions divided into 14 concentric circles around the center of the polishing layer on the polishing surface, a plurality of first protrusions with a diameter of 200 μm provided within each polishing region, and a plurality of second protrusions with a diameter of 200 μm provided at predetermined locations on the boundary of the polishing regions to adjust the distance from the first protrusions. When the polishing region closest to the center of the polishing surface was designated as the 1st polishing region and the polishing region furthest from the center as the 14th polishing region, the width of the 1st and 2nd polishing regions was 4.2 mm, the width of the 3rd to 5th polishing regions was 7.2 mm, the width of the 6th to 11th polishing regions was 30 mm, and the width of the 12th to 14th polishing regions was 60 mm. In other words, the width of the polishing region closer to the center of the polishing surface was narrower than the width of the polishing region located on the outer periphery of the polishing surface. In each polishing region, multiple first protrusions were arranged at predetermined intervals so as a whole they radiated radially along the first direction, which is the radial direction of the polishing surface, centered on the center of the polishing surface, and spiraled along the second direction, which gradually moves away from the center as it rotates around the center of the polishing surface. In two adjacent polishing regions, the number of linear first protrusions was greater in the outer polishing region than in the inner polishing region. In each polishing region, multiple first protrusions were arranged to form multiple spirals in the second direction. The first center-to-center distance D1, the second center-to-center distance D2, and the distance D3 are shown in Table 1. The width of each polishing region was an integer multiple of the first center-to-center distance D1.

[0079] <Comparative Example 1> In Comparative Example 1, the polished layer was obtained in the same manner as in Example 1, except that the polished surface was not divided, and the multiple first protrusions were arranged radially and concentrically around the center of the polished surface, along the first direction, such that the first inter-center distance D1 was 600 μm. In Comparative Example 1, the number of linear first protrusions was 360 (center angle 1°), but since the polished area was not divided into multiple polishing regions, the distance between adjacent first protrusions in the circumferential direction increased to 0.35 mm, 0.87 mm, and 2.62 mm as the outer circumference increased from the center of the polished surface at 20 mm, 50 mm, and 150 mm. The first inter-center distance D1 and distance D3 of the polished layer in Comparative Example 1 are shown in Table 1.

[0080] <Comparative Example 2> In Comparative Example 2, the polished surface was not divided, and multiple first protrusions were arranged in a spiral pattern along the second direction, such that the second center-to-center distance D2 was 600 μm, but they were not arranged radially along the first direction. A polished layer was obtained in the same manner as in Example 1. In Comparative Example 2, there were 100 spiral-shaped first protrusions, and the spiral-shaped first protrusions formed a continuous, curved spiral across the entire surface of the polished layer. The second center-to-center distances D2 and D3 of the polished layer in Comparative Example 2 are shown in Table 1.

[0081] [Table 1]

[0082] <Analysis of polishing rate stability> Using polishing pads with the polishing layers described in Example 1 and Comparative Examples 1 and 2, wafers were polished under the following polishing conditions, and the polishing rates for the center and the entire wafer were determined. The stability of the center polishing rate and the overall polishing rate were then evaluated. (polishing conditions) • Polishing machine used: F-REX300X (manufactured by Ebara Corporation) • Polishing pressure: 2.5 psi • Abrasive: Highly selective colloidal silica slurry (manufactured by Fujimi Incorporated Co., Ltd.), 10-fold dilution • Dresser: Dresser (made by KINIK) Pad break-in conditions: 20N x 5 minutes, dresser rotation speed 72 rpm, platen rotation speed 80 rpm, ultrapure water supply 1000 mL / min Conditioning: Ex-situ, 10N, 4 scans, 16 seconds Polishing: Plate rotation speed 90 rpm, polishing head rotation speed 81 rpm, polishing slurry flow rate 200 mL / min ·Polishing time: 60 seconds

[0083] Fifty wafers were polished under the above polishing conditions. The polishing rates for the center and the entire wafer were determined for wafers 5, 10, 15, 25, 35, and 50, and the polishing rate stability was evaluated using the following formula. A smaller value for polishing rate stability indicates higher stability. For center polishing rate stability, a value of less than 10% is preferable, and for overall polishing rate stability, a value of less than 20% is preferable. Center polishing rate stability (%) = {|Polishing rate at the center of the wafer - Average polishing rate of the entire wafer| / Average polishing rate of the entire wafer} × 100 Overall polishing rate stability (%) = {(Maximum overall wafer polishing rate - Minimum wafer polishing rate) / Average overall wafer polishing rate} × 100

[0084] The polishing rate (Å / min) was determined by dividing the polished thickness at each point by the polishing time, based on the thickness measurements taken at 149 locations on the TEOS film on the wafer before and after the polishing test. The thickness measurements were taken using the DBS mode of an optical film thickness and quality analyzer (KLA Tencor, model "ASET-F5x").

[0085] In the polishing of wafers using the polishing layer according to Comparative Example 1, although the overall polishing rate stability of the wafer was less than 20%, the polishing rate stability of the center was 10% or more, resulting in an undesirable profile at the center of the wafer. Similarly, in the polishing of wafers using the polishing layer according to Comparative Example 2, although the polishing rate stability of the center of the wafer was less than 10%, the overall polishing rate stability was 20% or more, resulting in an undesirable profile for the entire wafer, and the average polishing rate itself was lower compared to the polishing layers of Example 1 and Comparative Example 1. In contrast, in the polishing of wafers using the polishing layer according to Example 1, the polishing rate stability at the center of the wafer was less than 10%, and the overall polishing rate stability was also less than 20%. It is believed that the poor stability at the center of the wafer was due to variations in the protrusions that the wafer center contacted during polishing because the circumferential spacing of the first protrusions on the polishing pad of Comparative Example 1 widened towards the outer edge. Furthermore, in the case of the polishing pad in Comparative Example 2, the spiral-shaped first protrusions were arranged in a spiral across the entire polishing layer. Therefore, it is thought that the polishing rate increased when the trajectory of the wafer as it rotated during polishing largely overlapped with these vortices, and decreased when there was little overlap. This resulted in a large difference in the polishing rate depending on the location on the wafer, and the overall polishing rate stability was low. On the other hand, in the case of the polishing pad according to Example 1, the spacing of the first protrusions did not become too wide even on the outer circumference, and the spiral-shaped first protrusions were interrupted in the polishing area. As a result, it was confirmed that stable polishing was possible not only in parts other than the center of the wafer, but also across the entire wafer. [Explanation of Symbols]

[0086] 10… Polishing pad 10A…Surface 20...Base material 30...polishing layer 30A…Polished surface 31...Base 32, 32A, 32B... First convex section 32C...Linear first convex group 32D...Spiral-shaped first convex group 33...Second protrusion 90...Object to be polished 90A…Central Section D1… First intercenter distance D2…Second Intercenter Distance D3… Distance

Claims

1. A polishing pad comprising a polishing layer having a polishing surface for polishing an object to be polished, The polishing surface has a plurality of polishing regions divided concentrically around an arbitrary point on the polishing surface, and a plurality of first protrusions provided within each of the polishing regions. When the polished surface is viewed from the direction normal to the polished surface, in each of the polished regions, The diameter of each of the first protrusions is 100 μm or more and 500 μm or less. The multiple first protrusions are arranged at predetermined intervals so as a whole, they are radial along a first direction which is the radial direction of the polishing surface, centered on the reference point of the polishing surface, and spiral along a second direction which gradually moves away from the reference point as the polishing surface rotates around the reference point. The distance between the first centers of two adjacent first protrusions in the first direction is between 2 and 4 times the diameter of the first protrusion. The distance between the second centers of two adjacent first protrusions in the second direction is 2.5 times or more and 5 times or less the diameter of the first protrusion. A polishing pad in which, in two adjacent first protrusions in the second direction, the first protrusion closer to the reference point on the polishing surface is designated as the first protrusion (A), and the first protrusion further from the reference point on the polishing surface than the first protrusion (A) is designated as the first protrusion (B), the distance from the intersection of a virtual circle centered on the reference point on the polishing surface and passing through the center of the first protrusion (A) and a virtual line connecting the reference point on the polishing surface and the center of the first protrusion (B) to the center of the first protrusion (B) is between 1 / 4 and 1 times the diameter of the first protrusion.

2. The polishing pad according to claim 1, wherein the width of each polishing region is an integer multiple of the first center-to-center distance.

3. The polishing pad according to claim 1, wherein the width of the polishing region closer to the reference point than the outer periphery of the polishing surface is narrower than the width of the polishing region located on the outer periphery of the polishing surface.

4. The polishing pad according to claim 1, wherein, in two adjacent polishing regions, the polishing region closer to the reference point of the polishing surface is defined as polishing region (R1), and the polishing region further from the reference point of the polishing surface than polishing region (R1) is defined as polishing region (R2), and the polishing surface further has a second protrusion with a diameter of 100 μm or more and 500 μm or less at the boundary between polishing region (R1) and polishing region (R2) for adjusting the distance between the first protrusion located on the outermost side of polishing region (R1) and the first protrusion located on the innermost side of polishing region (R2).

5. The polishing pad according to claim 1, wherein in two adjacent polishing regions, the polishing region closer to the reference point on the polishing surface is designated as polishing region (R1), and the polishing region further from the reference point on the polishing surface than polishing region (R1) is designated as polishing region (R2), and when the plurality of first protrusions that form a radial pattern and are arranged in a line in the radial direction are designated as a linear first protrusion group, the polishing region (R2) has more linear first protrusion groups than the polishing region (R1).

6. The polishing pad according to claim 1, wherein in each of the polishing regions, the plurality of first protrusions are arranged to form a plurality of spirals in the second direction.

7. A polishing device comprising the polishing pad described in claim 1.

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