Polishing pad

Abstract

The present application is a polishing pad having a polishing layer with a circular polishing surface, and having spiral grooves formed from the central region to the peripheral region of the polishing surface, or concentric circular grooves formed by a plurality of annular grooves arranged in concentric circles, and radial grooves formed by line segment grooves extending from the central region to the peripheral region. Furthermore, the line segment grooves have a first end portion in a region at a distance of 5 to 10% of the radius of the polishing surface from the center of the radial grooves, and a second end portion in a region at a distance of 35 to 70% of the radius of the polishing surface from the center of the radial grooves, and have an average length in proportion to the radius of the polishing surface of 30 to 65%. Furthermore, the cross-sectional area Sa (mm 2 ) of the line segment grooves and the cross-sectional area Sb (mm 2 ) of the spiral grooves or the concentric circular grooves satisfy 0.1 ≤ Sb / Sa < 1.0.

Description

Technical Field

[0001] This invention relates to polishing pads that are preferably used for chemical mechanical polishing (CMP). Background Technology

[0002] In the past, chemical mechanical polishing (CMP) was used to perform mirror finishing on substrate materials such as semiconductors and silicon wafers, glass used as materials for hard disks, liquid crystal displays, and lenses, or to flatten the unevenness formed by insulating films and metal films in the manufacturing process of semiconductor devices. This involved applying polishing slurry (hereinafter also referred to as slurry) to the polishing surface of a polishing pad while pressing the material to be polished onto the polishing pad and polishing it.

[0003] For polishing pads used in CMP, grooves such as spiral grooves, concentric grooves, grid grooves, and radial grooves are formed to ensure that the slurry is retained on the entire polishing surface without leakage, to remove polishing debris, and to prevent damage caused by the adsorption of the polished material.

[0004] For example, Patent Document 1 discloses a polishing pad for a semiconductor wafer, wherein a plurality of radial grooves are formed in the portion that contacts the central portion of the wafer during polishing, extending from the center outwards, and a plurality of circular grooves concentric with the polishing pad are formed in at least the portion that contacts the peripheral portion of the wafer. Furthermore, it discloses that the width of the portion in which the radial grooves are formed is approximately half the diameter of the wafer.

[0005] Additionally, for example, Patent Document 2 discloses a polishing pad in which radial grooves and concentric grooves open on the polishing side surface of the polishing layer in a manner that shares a common center and intersects with each other. When the intersection of the radial grooves and concentric grooves is a radial groove, the radial grooves and concentric grooves satisfy the following conditions: (A) the area (s1) of the radial grooves accounts for 8 to 17% of the sum of the areas (s1) of the radial grooves and the areas (s2) of the concentric grooves (s1+s2), and (B) the sum of the areas (s1) of the radial grooves and the areas (s2) of the concentric grooves (s1+s2) accounts for 18 to 25% of the area (S) of the polishing side surface.

[0006] Additionally, for example, Patent Document 3 discloses a polishing pad comprising a polishing layer and a plurality of supply grooves (δ) intersecting with a radius. The polishing layer includes a center, a periphery, a radius extending from the center to the periphery, and polishing tracks surrounding the center and intersecting with the radius. Between the supply grooves (δ) are raised areas for planarizing the material to be polished. Furthermore, the polishing pad includes: having an average supply cross-sectional area (δ) aThe polishing pad comprises multiple supply channels (δ) and at least one radial drainage channel (ρ) in a polishing layer intersecting the multiple supply channels (δ), the at least one radial drainage channel (ρ) being used to allow polishing fluid to flow from the multiple supply channels (δ) to the at least one radial drainage channel (ρ). Furthermore, for the polishing pad, it is disclosed that the radial drainage channel (ρ) has an average drainage cross-sectional area (ρa). a According to 2×δ a ≤ρ a ≤8×δ a (0.15)n f ×δ a ≤n r ×ρ a ≤(0.35)n f ×δ a (where, (n r (n) represents the number of radial grooves. f (indicates the number of supply channels), and the average drainage cross-sectional area (ρ) of the radial drainage channels. a ) greater than the average supply cross-sectional area (δ) a The radial drainage groove (ρ) extends through the polishing track, facilitating the removal of polishing debris from the periphery of the polishing pad under at least one of the semiconductor substrate, optical substrate, and magnetic substrate during the rotation of the polishing pad, passing through and over the polishing track.

[0007] Additionally, for example, Patent Document 4 discloses a polishing pad comprising: a central track having a rotation center at the center of a polishing layer and a center arranged at intervals from the rotation center; an annular groove having a plurality of annular grooves arranged with the center as a concentric circle; and a groove extending radially, wherein a plurality of intersections are provided in the central track.

[0008] Additionally, for example, Patent Document 5 discloses a polishing pad having: a first region having both radially extending grooves and annular grooves that do not extend to the center of the polishing layer, and a second region having only annular grooves, wherein the radius of the first region is 30 to 70% of the radius of the polishing pad.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2000-237950

[0012] Patent Document 2: Japanese Patent Application Publication No. 2011-177884

[0013] Patent Document 3: Japanese Patent Application Publication No. 2017-208530

[0014] Patent Document 4: TW M459065U1 Publication

[0015] Patent Document 5: TW I548484 Publication Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] In CMP (Chemical Polishing), polishing pads are required to achieve higher polishing speeds. The object of this invention is to provide a polishing pad for achieving high polishing speeds in CMP.

[0018] Problem Solving Methods

[0019] One aspect of the present invention is a polishing pad comprising a polishing layer having a circular polishing surface. The polishing surface has a central region extending from its center relative to a radius of 0-10%, and a peripheral region extending to a radius of 90-100%. The polishing layer has at least one spiral groove arranged from the central region to the peripheral region, or a concentric circular groove formed by a plurality of annular grooves arranged in a concentric circle, and further has radial grooves formed by at least two segmental grooves extending from the central region to the peripheral region. The center of the spiral groove, the center of the concentric circular groove, and the center of the radial groove are located in the central region. The segmental grooves have an average length proportional to a radius of 30-65% of the polishing surface, and have a first end in a region extending from the center of the radial groove at a distance of 5-10% of the radius of the polishing surface, and a second end in a region extending at a distance of 35-70%. Furthermore, the cross-sectional area Sa (mm²) 2 ) and cross-sectional area Sb (mm 2 The condition 0.1 ≤ Sb / Sa < 1.0 is satisfied, where Sa is the average cross-sectional area of ​​the segmental groove in the direction perpendicular to the length direction, and Sb is the average cross-sectional area of ​​the spiral groove or concentric circular groove in the direction perpendicular to the tangent direction.

[0020] Here, the polished surface refers to the surface of the polished layer that is in contact with the material being polished. Additionally, for example, see reference... Figure 7 The central region refers to the area represented by points ranging from 0% to 10% of the radius of the circular polished surface, i.e., the circular region R1. The peripheral region refers to the area ranging from 90% to 100% of the radius of the circular polished surface, specifically, the band-shaped region R2 represented by points along the perimeter of the circle with a radius of 90% to 100%.

[0021] In addition, a segmental groove refers to a linear groove that does not reach the periphery of the polished surface but has two ends within the polished surface. A spiral groove is at least one spiral groove with a spiral center in the central region of the polished surface. A concentric circular groove is formed by multiple annular grooves having a common center in the central region of the polished surface and arranged in a concentric circle. Furthermore, a spiral groove or concentric circular groove arranged from the central region to the peripheral region means that at least one spiral groove or multiple annular grooves arranged in a concentric circle are formed throughout the entire area from the central region to the peripheral region of the polished surface. Specifically, in the case of a concentric circular groove, the groove closest to the center passes through the central region, and the outermost groove passes through the peripheral region. In the case of a spiral groove, the starting point of the spiral groove is in the central region, and the ending point of the spiral groove is in the peripheral region. Finally, a polishing area refers to the area in the polished surface that contacts the polished surface of the material being polished, such as a silicon wafer, and polishes the material.

[0022] In such a polishing pad, multiple linear grooves prevent slurry dripping onto the polishing surface and accumulating near the central area from leaking out of the system from the periphery of the polishing surface, while moderately supplying slurry to spiral and concentric grooves formed from the central area to the periphery. As a result, a very high polishing speed can be achieved by efficiently supplying slurry to the polishing area.

[0023] In addition, considering the need for higher polishing speed and excellent polishing uniformity within the polished surface of the material, it is preferable that the polishing pad satisfies 0.25≤Sb / Sa≤0.85, and even more preferably 0.44≤Sb / Sa≤0.80.

[0024] Furthermore, for the polishing pad, it is preferable that the average width of the linear grooves, i.e., the groove width Wa (mm), and the average width of the spiral grooves or concentric circular grooves, i.e., the groove width Wb (mm), satisfy 0.1 ≤ Wb / Wa < 1.0. Under such conditions, the slurry can be maintained more thoroughly throughout the polishing area, thus achieving a higher polishing speed.

[0025] Furthermore, for polishing pads, it is preferable that the average width of the spiral or concentric grooves, i.e., the groove width Wb (mm), and the average groove spacing P (mm) of the spiral or concentric grooves satisfy 0.02 ≤ Wb / P ≤ 0.25. In this case, the area of ​​the boss region in contact with the material being polished can be sufficiently ensured, and a sufficient amount of slurry can be supplied to the boss region, thus achieving a higher polishing speed. It should be noted that, in the case of spiral grooves, the groove spacing P refers to the average of the sum of the interval between adjacent spiral grooves and the groove width; in the case of concentric grooves, the groove spacing P refers to the average of the sum of the interval between adjacent annular grooves and the groove width.

[0026] Furthermore, for polishing pads, the average width of the linear grooves (i.e., groove width Wa (mm), the average width of the spiral or concentric grooves (i.e., groove width Wb (mm), and the average groove spacing P (mm) of the spiral or concentric grooves preferably satisfy 0.2 ≤ {Wb} 2 / (P×Wa)}×100≤25. Under such circumstances, a higher polishing speed can be achieved by rapidly supplying the slurry to the polishing area and maintaining the slurry sufficiently between the polishing surface and the polished surface of the material being polished.

[0027] Furthermore, in the polishing pad, considering excellent low scratch resistance and ease of molding, it is preferable that the polishing layer comprises thermoplastic polyurethane. Additionally, considering excellent stability of polishing speed and ease of molding, it is preferable that the polishing layer is non-foamed.

[0028] The effects of the invention

[0029] According to the present invention, a high-speed polishing pad that can easily achieve the polishing speed of CMP can be obtained. Attached Figure Description

[0030] Figure 1 This is a plan view of the polishing surface side of the polishing layer 1 of the polishing pad 10 with spiral grooves according to the embodiment.

[0031] Figure 2 This is a plan view of the polishing surface side of the polishing layer 11 of the polishing pad 20 with concentric circular grooves in the embodiment.

[0032] Figure 3A It is a schematic diagram of a cross-section of a spiral groove or concentric circular groove in a direction perpendicular to the tangent direction.

[0033] Figure 3B This is a schematic diagram of a groove cross-section used to illustrate the angle of the bevel formed by chamfering the corners of the groove.

[0034] Figure 3C This is a schematic diagram of the cross-section of a groove used to illustrate the angle of the inclined surface of a groove with an inverted trapezoidal cross-section.

[0035] Figure 4 It is a schematic diagram of the cross-section of a segmental groove in a direction perpendicular to its length.

[0036] Figure 5 This is a partial cross-sectional schematic diagram of the thickness direction of polishing pad 10 or polishing pad 20.

[0037] Figure 6 This is an explanatory diagram used to illustrate CMP.

[0038] Figure 7 This is an explanatory diagram used to illustrate the central and peripheral areas of a polished surface.

[0039] Symbol Explanation

[0040] 1. Polishing layer 11

[0041] 10, 20 polishing pads

[0042] E1 First end

[0043] E2, second end

[0044] C1~C9 Annular grooves (concentric circular grooves)

[0045] S1~S8 Linear grooves (radial grooves)

[0046] H spiral groove

[0047] F Polished surface Detailed Implementation

[0048] The polishing pad of this embodiment will be described in detail with reference to the accompanying drawings.

[0049] Figure 1 This is a plan view of the polishing surface of a polishing pad 10, which is an example of a polishing pad in this embodiment. The polishing pad 10 includes a polishing layer 1 having a circular polishing surface. The polishing layer 1 has a spiral groove H formed from the central region to the peripheral region and a radial groove formed by eight line segment grooves S1 to S8 extending from the central region to the peripheral region.

[0050] in addition, Figure 2 This is a plan view of the polishing surface of a polishing pad 20, which is another example of a polishing pad in this embodiment. The polishing pad 20 includes a polishing layer 11 having a circular polishing surface. The polishing layer 11 has 11 annular grooves C1 to C11 arranged in a concentric circle from the central region to the peripheral region, and radial grooves formed by 8 line segment grooves S1 to S8 extending from the central region to the peripheral region.

[0051] Figure 7 This is an explanatory diagram used to illustrate the central region R1 and the peripheral region R2 of the polishing pad 10. Figure 7 In the polishing pad 10 shown, the circular area represented by points ranging from 0% to 10% of the radius from the center G of the circular polishing surface is called the central area R1, and the area ranging from 90% to 100% of the radius from the center of the polishing surface is called the peripheral area R2. More specifically, the area represented by points in a band along the periphery of the circle with a radius of 90% to 100% is called the peripheral area R2.

[0052] Figure 5 This is a partial cross-sectional schematic diagram in the thickness direction used to explain the layer composition of polishing pad 10 or polishing pad 20. Polishing pad 10 or polishing pad 20 has a laminated structure where a buffer layer 7 is sandwiched between an adhesive layer 6 and bonded to the polishing layers 1 and 11 on the side opposite to the polishing surface F. It should be noted that the polishing pad of this embodiment is not limited to polishing pads having such a laminated structure; it can be a single-layer polishing pad formed only of a polishing layer having a polishing surface.

[0053] Reference Figure 1 In the polishing pad 10, the polishing surface of the polishing layer 1 is circular. Furthermore, a spiral groove H is formed on this polishing surface, with the center G of the polishing surface included in the central region as its spiral center and extending from the central region to the peripheral region. Additionally, radial grooves are formed, comprising eight segmental grooves S1 to S8 extending from the central region to the peripheral region with the center G as its radial center. Thus, in the polishing pad 10, the spiral groove H and the radial grooves share a common center.

[0054] Additionally, refer to Figure 2 In the polishing pad 20, the polishing surface of the polishing layer 11 is circular. Furthermore, 11 concentric annular grooves C1 to C11 are formed on the polishing surface, arranged with the center G of the polishing surface included in the central region as a common center and extending from the central region to the peripheral region. Additionally, radial grooves are formed, each containing eight segmental grooves S1 to S8 extending from the central region to the peripheral region with the center G as the radial center. Thus, in the polishing pad 20, the annular grooves C1 to C11 and the radial grooves share a common center.

[0055] In polishing pads 10 and 20, the center G of the circular polishing surface that serves as the center of rotation, the center of the spiral groove or concentric circular groove, and the center of the radial groove are aligned. In this case, the flow of the slurry is more likely to be more uniform. It should be noted that the polishing pad of this embodiment may also have eccentric spiral grooves, concentric circular grooves, or radial grooves where the center of the polishing surface is not aligned with the center of the spiral groove, concentric circular groove, or radial groove. In the case of eccentric spiral grooves or concentric circular grooves, it is preferable from the viewpoint of easily suppressing the transfer of the shape of each groove to the polished surface of the polished material such as a wafer due to over-polishing along each groove.

[0056] The diameter of the circular polished surface is the same as that of a typical circular polishing pad used in CMP, preferably around 500 to 780 mm. Therefore, the radius of the circular polished surface is preferably around 250 to 390 mm.

[0057] In polishing pad 10 or polishing pad 20, the portions where the segmental grooves S1-S8 and the spiral grooves H or the concentric annular grooves C1-C11 are not formed become the boss areas that contact the polished surface of the material being polished and are polished. Polishing pad 10 and polishing pad 20 are the same polishing pads except for the spiral grooves H and the concentric annular grooves C1-C11. It should be noted that... Figure 1 The polishing pad 10 shown in the figure has spiral grooves H. Figure 2 The polishing pad 20 shown has concentric annular grooves C1 to C11. In the polishing pad of this embodiment, grooves that combine spiral grooves and concentric annular grooves can be formed.

[0058] Thus, the polishing pad of this embodiment has a spiral groove or concentric groove formed from the central region of the polishing surface to the peripheral region.

[0059] Thus, the spiral grooves or concentric grooves formed from the central region of the polished surface to the peripheral region are preferably formed from the center of the spiral or the center of the concentric circle to a region covering at least 5 to 90% of the radius of the polished surface, more preferably covering 4.5 to 95% of the region, and particularly preferably covering 4 to 100% of the region.

[0060] Reference Figure 1 In the polishing pad 10, a spiral groove H with a rotation number of 10 is formed, having a uniform groove spacing in a region extending at least 5 to 90% of the radius from the spiral center to the polishing surface. The spiral center coincides with the center G contained in the central region of the polishing surface of the polishing layer 1. It should be noted that a spiral with a uniform groove spacing is also called an Archimedean spiral. Furthermore, the grooves of the spiral groove H with rotation numbers of 1 to 6 intersect with the line segment grooves S1 to S8, forming 41 intersection points.

[0061] In a polishing layer with spiral grooves, the starting point is preferably located in a region of less than 5% of the radius from the center of the polished surface, more preferably less than 4.5% of the radius, and particularly preferably less than 4% of the radius. The ending point preferably reaches more than 90% of the radius, more preferably more than 95% of the radius, and particularly preferably 100% of the radius at the periphery. By forming spiral grooves over essentially the entire area from the central region to the periphery of the polished surface, the slurry can be distributed evenly throughout the entire polishing area.

[0062] The spiral groove can be a single spiral groove, or it can consist of two or more spiral grooves arranged in parallel. Specifically, the number of parallel spiral grooves is preferably 1 to 16, and more preferably 1 to 10.

[0063] Additionally, refer to Figure 2In the polishing pad 20, annular grooves C1 to C11 are formed, with equal groove spacing in a region extending at least 5 to 90% of the radius of the polishing surface from the center of the concentric circles. The center of the concentric circles coincides with the center G contained in the central region of the polishing surface of the polishing layer 11. Furthermore, in the annular grooves C1 to C11, annular grooves C2 to C6 intersect with line segment grooves S1 to S8, forming 40 intersections.

[0064] In a polished layer with concentric circular grooves, it is preferable to form concentric circular grooves in which the annular groove closest to the center of the polished surface passes through a region with a radius of less than 5%, further less than 4.5%, and particularly less than 4% of the radius from the center of the polished surface, and the outermost groove passes through a region with a radius of more than 90%, further more than 95% of the radius.

[0065] The spacing between adjacent spiral or concentric grooves, i.e., the groove spacing, is not particularly limited; refer to [reference needed]. Figure 3A The average spacing between adjacent grooves, i.e., the groove spacing P (mm), is preferably 1 to 15 mm, more preferably 2 to 12 mm, and particularly preferably 2 to 10 mm. If the groove spacing P of the spiral or concentric grooves is too large, the slurry supplied from the spiral or concentric grooves to the boss area may be insufficient. Conversely, if the groove spacing P is too small, the proportion of the boss area becomes too low, tending to reduce the polishing speed.

[0066] The cross-sectional shape of the spiral groove or concentric circular groove is not particularly limited. Specifically, the shape of the cross-section of the spiral groove or concentric circular groove in the direction perpendicular to the tangent direction is not limited, and rectangular, square, trapezoidal, inverted trapezoidal, triangular, semi-circular, semi-oblong, and other quadrilateral shapes can be used. Among these, a quadrilateral shape is preferred from the perspectives of excellent processability, slurry retention, and supply stability.

[0067] Furthermore, to suppress the formation of burrs during polishing, spiral grooves or concentric circular grooves preferably have a cross-section that is inclined in such a way that the grooves are oriented in an inverted conical shape toward the opening. Specifically, it is preferable to have a cross-section such as... Figure 3B As shown, it is a so-called Y-shaped conical portion having a chamfered corner at a given angle α, forming a groove with a quadrilateral shape on the polished surface, or as... Figure 3CAs shown, the cross-section is an inverted trapezoid formed by tilting the hypotenuse relative to the two corners forming the base angle at a given angle α. This tilt angle is not particularly limited, but is preferably 20 degrees or more and less than 90 degrees, more preferably 25 to 80 degrees, and particularly preferably 30 to 75 degrees. Especially when the angle is 30 to 80 degrees, it is easier to suppress the generation of burrs that easily form at the corners of the groove during polishing, thereby easily suppressing the decrease in polishing speed and the decrease in polishing uniformity.

[0068] Additionally, refer to Figure 3A Regarding the width of spiral or concentric circular grooves, considering particularly excellent polishing speed and uniformity, the average width of each groove, i.e., the groove width Wb (mm), is preferably 0.1 to 4 mm, and more preferably 0.2 to 2 mm. It should be noted that the width of the spiral or concentric circular groove is defined as follows in the cross-sectional shape when cut in a direction perpendicular to the tangent direction of the annular or spiral groove: In the case of a rectangular or square cross-section, it is defined as the width on the polished surface. In the case of a trapezoidal or inverted trapezoidal cross-section, it is defined as the average width of the lower base. In the case of a Y-shaped groove with a chamfered tapered portion, it is defined as the width of the groove cross-section on the polished surface assuming the tapered portion is not formed. In the case of triangular, semi-circular, or semi-oblong shapes, it is defined as the width at half the depth.

[0069] Furthermore, regarding the depth of the spiral or concentric grooves, considering both ensuring sufficient supply of slurry to the polishing area and stabilizing polishing performance by suppressing deformation of the polishing pad, the average depth of the deepest part of the spiral or concentric groove is preferably 0.3 to 3.0 mm, more preferably about 0.5 to 2.5 mm. If the spiral or concentric groove is too deep, its volume tends to increase, requiring more slurry to be supplied to ensure sufficient distribution of the polishing area during polishing, which is sometimes cost-inefficient. Conversely, if the spiral or concentric groove is too shallow, its volume tends to decrease, reducing the amount of slurry retained in the polishing area during polishing. This can lead to a decrease in the amount of slurry supplied to the boss areas of the polishing area, resulting in a lower polishing speed.

[0070] Furthermore, regarding the cross-sectional area of ​​spiral or concentric grooves, considering the need to adequately ensure the supply of slurry to the polishing area, such as... Figure 3A As shown, the average cross-sectional area of ​​the section perpendicular to the tangent direction, i.e., the cross-sectional area Sb (mm²) 2 The preferred diameter is 0.2–4.5 mm. 2 Further, the thickness is 0.3–4.0 mm. 2When the cross-sectional area Sb is too large, more slurry must be added to ensure sufficient coverage of the polishing area, which is sometimes not cost-effective. Conversely, when the cross-sectional area Sb is too small, there is a tendency for the amount of slurry supplied to the polishing area to decrease, leading to a reduction in polishing speed. It should be noted that the average cross-sectional area is also the average cross-sectional area of ​​each tank.

[0071] It should be noted that the groove spacing P, groove width Wb, depth, and cross-sectional area Sb of the spiral groove or concentric groove are based on the unused polishing pad before the running-in process.

[0072] Furthermore, as described above, the polishing pad of this embodiment includes radial grooves comprising at least two segmental grooves extending from the central region of the polishing surface to the peripheral region. Each segmental groove has a first end in a region extending 5 to 10% of the radius of the polishing surface from the center of the radial groove. It also has a second end in a region extending 35 to 70% of the radius of the polishing surface from the center of the radial groove. Here, the center of the radial groove refers to the position of the centroid of the first ends of all the segmental grooves. Moreover, the average length of the segmental groove is 30 to 65% of the length of the polishing surface relative to the radius of the polishing surface. These segmental grooves form intersections with spiral grooves or concentric circular grooves within the polishing surface.

[0073] It should be noted that a distance of 5% of the radius of the polished surface from the center of the radial groove refers to a distance of 5% of the length of the polished surface from the center of the radial groove. Similarly, a distance of 10% of the radius of the polished surface from the center of the radial groove refers to a distance of 10% of the length of the polished surface from the center of the radial groove.

[0074] Reference Figure 1 In the polishing pad 10, the segmental grooves S1 to S8 formed on the polishing surface have a first end E1 in a region extending 5 to 10% of the radius of the polishing surface from the center G of the radial grooves. The center G of the radial grooves coincides with the center of the spiral groove H. Furthermore, a second end E2 is formed in a region extending 35 to 70% of the radius of the polishing surface from the center G of the radial grooves. The center G of the radial grooves coincides with the center of the spiral groove H. Moreover, the segmental grooves S1 to S8 have an average length that is 30 to 65% of the radius of the polishing surface. Additionally, refer to... Figure 2In the polishing pad 20, the segmental grooves S1 to S8 formed on the polishing surface have a first end E1 in a region extending 5 to 10% of the radius of the polishing surface from the center G of the radial groove. The center G of the radial groove coincides with the center of the concentric annular grooves C1 to C11. Furthermore, a second end E2 is formed in a region extending 35 to 70% of the radius of the polishing surface from the center G of the radial groove. The center G of the radial groove also coincides with the center of the concentric annular groove. Moreover, the segmental grooves S1 to S8 have an average length that is 30 to 65% of the radius of the polishing surface.

[0075] That is, in the polishing pad 10 or polishing pad 20 of this embodiment, each of the eight segmental grooves S1 to S8 has a first end point E1 arranged along an imaginary circle K1 representing a position approximately 7% of the radius of the polishing surface from the center G of the radial groove, and a second end point E2 arranged along an imaginary circle K2 representing a position approximately 52.5% of the radius of the polishing surface from the center G of the radial groove. Furthermore, the eight segmental grooves S1 to S8 have an average length that is approximately 45.5% of the radius of the polishing surface.

[0076] When the first end of the segmental groove is located in a region 5 to 10% of the radius of the polishing surface from the center of the radial groove, the slurry dripped onto the polishing surface can penetrate the segmental groove at an appropriate time, making it easy to distribute the slurry evenly in the polishing area.

[0077] When the first end is located in a region less than 5% of the radius of the polishing surface from the center of the radial groove, the slurry accumulated near the central region of the polishing surface tends to preferentially enter the segmental groove compared to spiral or concentric grooves. This results in uneven slurry supply near the central region and a decrease in polishing speed. Furthermore, when the first end, which forms the starting point of the segmental groove, is located in a region exceeding 10% of the radius of the polishing surface from the center of the radial groove, the slurry accumulated near the central region has difficulty penetrating the segmental groove, thus easily reducing the slurry supply to the polishing area.

[0078] On the other hand, a second end, which becomes the endpoint of the segmental groove, is formed in a region existing at a distance of 35 to 70% of the radius from the center of the radial groove relative to the polishing surface. When the second end, which becomes the endpoint of the segmental groove, exists in a region at a distance of 35 to 70% of the radius from the center of the radial groove relative to the polishing surface, the slurry immersed in the segmental groove from near the central region is adequately delivered to the polishing area, but is not delivered to the vicinity of the peripheral region of the polishing surface. Therefore, the slurry is less likely to leak out of the system from the periphery of the polishing surface, and a sufficient amount of slurry is easily maintained in the polishing area. The second end of the segmental groove is further preferably located in a region at a distance of 40 to 65% of the radius from the center of the radial groove relative to the polishing surface.

[0079] When the second end of the segmented groove is located in a region less than 35% of the radius of the polishing surface from the center of the radial groove, the length of the segmented groove becomes too short. The slurry immersed in the segmented groove cannot adequately reach the polishing area, resulting in insufficient slurry supply and a reduced polishing speed. Conversely, when the second end of the segmented groove is located in a region exceeding 70% of the radius of the polishing surface from the center of the radial groove, excessive slurry is supplied to the periphery of the polishing surface. This causes slurry to easily leak out of the system from the periphery, resulting in waste. Consequently, the distribution of slurry in the polishing area becomes uneven, further reducing the polishing speed.

[0080] The average length of the segmented grooves constituting such radial grooves is 30-65%, preferably 35-60%, of the radius of the polishing surface. When the average length of the segmented grooves is less than 30% of the radius of the polishing surface, the slurry immersed in the segmented grooves cannot adequately reach the polishing area, resulting in insufficient slurry supply and reduced polishing speed. Conversely, when the average length of the segmented grooves exceeds 65% of the radius of the polishing surface, excessive slurry is supplied to the periphery of the polishing surface, causing slurry to easily leak out of the system and be wasted. It should be noted that the average length of the segmented grooves is also the average of the lengths of the individual segmented grooves.

[0081] The number of segmented grooves constituting the radial grooves can be two or more, with no particular limitation. However, to achieve a good balance between slurry supply and discharge, and considering the improvement of slurry retention in the polishing area, 4 to 24 grooves are preferred, and more preferably 5 to 16. If the number of segmented grooves is too small, the slurry supply to the polishing area may be insufficient. If the number is too large, the discharge to the polishing surface becomes too high, resulting in insufficient slurry supply per groove on average, and a tendency for uneven slurry supply to the polishing area.

[0082] The segmental groove can be straight or curved. From the perspective of easy control of the slurry supply or discharge, a straight groove is preferred.

[0083] The cross-sectional shape of the segmental groove is not particularly limited. Specifically, the shape of the cross-section of the segmental groove in the direction perpendicular to its length is not particularly limited, and it can use rectangular, square, trapezoidal, inverted trapezoidal, triangular, semi-circular, semi-oblong, etc. Among these, a quadrilateral shape is preferred from the perspectives of excellent processability, slurry retention, and supply stability.

[0084] Furthermore, to suppress the formation of burrs during polishing, the segmental groove preferably has a cross-section that is inclined in a way that the groove faces the opening in an inverted conical shape. Specifically, it is preferable to have a so-called Y-shaped conical portion with two corners of the groove forming a quadrilateral shape on the polishing surface being chamfered at a given angle β, or an inverted trapezoidal cross-section formed with the inclined side inclined relative to the two corners forming the base corner at a given angle β. The angle of such inclination is not particularly limited, but is preferably 20 degrees or more and less than 90 degrees, more preferably 25 to 80 degrees, and particularly preferably 30 to 75 degrees. Especially when the angle is 30 to 80 degrees, it is easy to suppress the formation of burrs that are prone to occur at the corners of the groove during polishing, thereby easily suppressing the reduction in polishing speed and the reduction in polishing uniformity.

[0085] Additionally, refer to Figure 4 Regarding the width of the segmental grooves, considering the good balance between the areas of the radial grooves and the boss areas, the average width of each segmental groove, i.e., the groove width Wa (mm), is preferably 0.1 to 10 mm, and more preferably 0.2 to 5 mm. It should be noted that, in the cross-sectional shape when cut in a direction perpendicular to the length direction, the width of the segmental groove is defined in the same way as the width of the spiral groove or concentric circular groove described above.

[0086] Furthermore, regarding the depth of the segmental groove, considering both ensuring sufficient supply of slurry to the polishing area and suppressing the deformation of the polishing pad to stabilize polishing performance, the depth is preferably 0.3 to 3.0 mm, more preferably 0.5 to 2.5 mm, based on the average depth of the deepest part of the segmental groove. If the segmental groove is too deep, its volume tends to increase, requiring more slurry to be added to the polishing area to ensure sufficient slurry distribution, which is sometimes cost-inefficient. Conversely, if the segmental groove is too shallow, its volume tends to decrease, causing slurry to overflow from the central raised area during polishing, making it difficult for the slurry to reach the polishing area adequately. Additionally, if the segmental groove is too shallow, it will become even shallower due to wear on the polishing surface with continuous use of the polishing pad, making it difficult to sustain the effect of increasing polishing speed.

[0087] In addition, such as Figure 4 As shown, the average cross-sectional area of ​​the section perpendicular to the length direction is set as the cross-sectional area Sa (mm). 2 In the case of ensuring the supply of slurry to the polishing area, the cross-sectional area of ​​the segmental groove is preferably 0.3 to 4.5 mm². 2 A further preferred size is 0.5–4.0 mm. 2 When the average cross-sectional area of ​​the segmental grooves is too large, more slurry must be added to the polishing surface to ensure sufficient coverage during polishing, which is sometimes cost-inefficient. Conversely, if the average cross-sectional area of ​​the segmental grooves is too small, the slurry may overflow from the central raised area before reaching the polishing surface, resulting in insufficient coverage of the polishing area. It should be noted that the average cross-sectional area of ​​the segmental grooves is also the average of the cross-sectional areas of all individual segmental grooves.

[0088] It should be noted that the depth, width Wa, and cross-sectional area Sa of the segmented groove are also based on the unused polishing pad before the break-in process.

[0089] In this embodiment, the polishing pad contains the intersection of segmental grooves and spiral grooves or concentric circular grooves in a region of 5 to 70% of the radius of the polishing surface starting from the center of the radial grooves.

[0090] Reference Figure 1In the polishing surface of the polishing layer 1 of the polishing pad 10, a spiral groove H with an equal groove spacing P and a rotation number of 10 is formed in a region of 4.5% to 100% of the radius of the polishing surface from the spiral center. Furthermore, the spiral grooves H with rotation numbers of 1 to 6 intersect with the line segment grooves S1 to S8, forming 41 intersections. These intersections exist within a region of approximately 7% to 52.5% of the radius surrounded by imaginary circles K1 and K2, where imaginary circle K1 represents a position approximately 7% of the radius of the polishing surface from the center of the spiral groove H, and imaginary circle K2 represents a position approximately 52.5% of the radius of the polishing surface from the center of the spiral groove H.

[0091] Additionally, refer to the same Figure 2 In the polishing surface of the polishing layer 21 of the polishing pad 20, concentric annular grooves C1 to C11 with equal groove spacing P are formed in an area extending at least 5 to 90% of the radius of the polishing surface from the center of the concentric circles. Furthermore, each of the segmental grooves S1 to S8 intersects with the annular grooves C2 to C6, forming 40 intersections. These intersections exist within a region surrounded by imaginary circles K1 and K2, and are located at a distance of approximately 7 to 52.5% of the radius of the polishing surface from the center. Imaginary circle K1 represents a position approximately 7% of the radius of the polishing surface from the center G of the concentric groove, and imaginary circle K2 represents a position approximately 52.5% of the radius of the polishing surface from the center of the spiral groove H.

[0092] Thus, by having intersecting sections of segmental grooves and spiral or concentric grooves within a region extending 5–70% of the radius from the center of the radial groove relative to the polishing surface, the slurry immersed in the segmental groove can be easily and rapidly supplied to and held in the polishing area. When the intersecting section exists in a region extending more than 70% of the radius from the center of the radial groove relative to the polishing surface, the slurry tends to over-spread to the periphery of the polishing surface during polishing, easily overflowing from the periphery of the polishing surface into the system. As a result, the amount of slurry held in the polishing area decreases, and the polishing speed decreases. Furthermore, when the intersecting section exists in a region extending less than 5% of the radius from the center of the radial groove relative to the polishing surface, the slurry dripped onto the polishing surface is directly dripped into the segmental groove, easily causing rebound, thus easily creating a deviation in the supply speed within the polishing surface.

[0093] Furthermore, for the polishing pad of this embodiment, the average cross-sectional area Sa (mm²) of the cross-section of the segmental groove in the direction perpendicular to the length direction is... 2 The average cross-sectional area Sb (mm²) is the cross-sectional area of ​​the sections perpendicular to the tangent direction of spiral grooves or concentric grooves. 2The condition is satisfied that 0.1 ≤ Sb / Sa < 1.0, and preferably 0.15 ≤ Sb / Sa ≤ 0.85. Figure 3A The figure shows the cross-sectional area Sb of a spiral groove or concentric circular groove in a direction perpendicular to the tangent direction. Figure 4 The figure shows the cross-sectional area Sa of the section of the linear groove in the direction perpendicular to its length.

[0094] When the ratio of the cross-sectional area Sb of the spiral or concentric grooves to the cross-sectional area Sa of the segmental grooves (Sb / Sa) is 1.0 or higher, the slurry tends to flow into the spiral or concentric grooves, thereby reducing the slurry supply to the polishing area and decreasing the polishing speed. Conversely, when Sb / Sa is less than 0.1, the slurry flows too preferentially into the segmental grooves, causing slurry to overflow from the protrusions near the central area of ​​the polished surface, resulting in a tendency for reduced slurry supply to the polishing area.

[0095] Furthermore, considering the need to achieve higher polishing speeds and thus better polishing uniformity on the polished surface of the material, Sb / Sa is preferably 0.25≤Sb / Sa≤0.85, and more preferably 0.44≤Sb / Sa≤0.80.

[0096] Furthermore, for the polishing pad of this embodiment, considering the tendency to improve the supply of slurry to the polishing area by rapidly allowing it to flow into the segmented grooves, it is preferable that the average width of the segmented grooves, i.e., the groove width Wa (mm), is greater than the average width of the spiral grooves or concentric grooves, i.e., the groove width Wb (mm). Specifically, it is preferable that 0.1 ≤ Wb / Wa < 1.0, more preferably 0.1 ≤ Wb / Wa ≤ 0.9, and particularly preferably 0.1 ≤ Wb / Wa ≤ 0.6. When the ratio of groove width Wb to groove width Wa, Wb / Wa, is too high, the slurry tends to flow into the spiral or concentric grooves, thus tending to reduce the supply of slurry to the polishing area. Conversely, when Wb / Wa is too low, the slurry flows too preferentially into the segmented grooves, thus causing the slurry to overflow into the protrusion area near the central region of the polished surface, further reducing the supply of slurry to the polishing area.

[0097] Furthermore, for the polishing pad of this embodiment, the average width of the spiral groove or concentric groove, i.e., the groove width Wb (mm), and the groove spacing P (mm) preferably satisfy 0.02 ≤ Wb / P ≤ 0.25, and more preferably 0.025 ≤ Wb / P ≤ 0.16. If the average width of the spiral groove or concentric groove is too large relative to the groove spacing P (mm), there is a tendency for the polishing surface in contact with the material being polished to become too small, thus reducing polishing efficiency. If it is too small, there is a tendency for insufficient slurry supplied through the grooves to reach the polishing surface.

[0098] Furthermore, for the polishing pad of this embodiment, the average width of the linear grooves, i.e., the groove width Wa (mm), the average width of the spiral grooves or concentric circular grooves, i.e., the groove width Wb (mm), and the average groove spacing P (mm) of the spiral grooves or concentric circular grooves preferably satisfy 0.20 ≤ {Wb} 2 / (P×Wa)}×100≤25, further optimization satisfies 0.25≤{Wb 2 / (P×Wa)}×100≤15, with a particularly preferred condition satisfying 0.25≤{Wb} 2 / (P×Wa)}×100≤10. In {Wb 2 When the value of / (P×Wa)}×100 is too large, the slurry tends to preferentially flow into the spiral or concentric grooves, thereby reducing the supply of slurry to the polishing area. Additionally, in {Wb 2 When / (P×Wa)}×100 is too small, the slurry preferentially penetrates the segmented groove, thereby causing the slurry to overflow in the protrusion area near the central region of the polished surface, resulting in a tendency for the supply of slurry to the polishing area to decrease.

[0099] The material used to form the polishing layer in the polishing pad of this embodiment is not particularly limited, and synthetic or natural polymeric materials conventionally used in the manufacture of polishing layers for polishing pads can be used. Specific examples of polymeric materials forming the polishing layer include: polyurethane, polyethylene, polypropylene, polybutadiene, ethylene-vinyl acetate copolymer, butyral resin, polystyrene, polyvinyl chloride, acrylic resin, epoxy resin, polyester, polyamide, etc. These can be used alone or in combination of two or more. Among these, polyurethane is particularly preferred as the main component, considering the need for a polishing layer with excellent planarity and resistance to scratches. Hereinafter, polyurethane used as the material forming the polishing layer will be described in detail with representative examples.

[0100] Polyurethane can be obtained by reacting a polyurethane raw material containing a polymeric diol, an organic diisocyanate, and a chain extender. Examples of polymeric diols, organic diisocyanates, and chain extenders used as polyurethane raw materials include, for example, the compounds described below.

[0101] Specific examples of high molecular weight diols include: polyethylene glycol, polytetramethylene glycol, and other polyether diols; poly(nonamethylene adipate) diol, poly(2-methyl-1,8-octamethylene adipate) diol, poly(3-methyl-1,5-pentamethylene adipate) diol, and other polyester diols; poly(hexamethylene carbonate) diol, poly(3-methyl-1,5-pentamethylene carbonate) diol, and other polycarbonate diols. They can be used alone or in combination of two or more.

[0102] Specific examples of organic diisocyanates include aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-bis(isocyanate methyl)cyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 1,5-naphthalene diisocyanate. These can be used alone or in combination of two or more. Among these, 4,4'-diphenylmethane diisocyanate is preferred due to its superior wear resistance of the resulting polished layer.

[0103] In addition, as chain extenders, examples include low-molecular-weight compounds with a molecular weight of 350 or less that have two or more active hydrogen atoms capable of reacting with isocyanate groups. Specific examples include: diethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-bis(β-hydroxyethoxy)benzene, 1,9-nonanediol, cis-2-buten-1,4-diol, spirodiol, and other diols; and diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, hydrazine, phenylenedimethyldiamine, isophoronediamine, and piperazine. These can be used alone or in combination of two or more. Particularly preferred is at least one selected from 1,4-butanediol, cis-2-buten-1,4-diol, 1,5-pentanediol, and 1,9-nonanediol.

[0104] The proportions of each component in the polyurethane raw material can be appropriately adjusted to consider the desired properties imparted to the polishing layer. For example, relative to 1 mole of active hydrogen atoms contained in the polymer glycol and chain extender, it is preferable to proportion the isocyanate groups in the organic diisocyanate to be 0.95 to 1.3 moles, more preferably 0.96 to 1.1 moles, and particularly preferably 0.97 to 1.05 moles. If the isocyanate groups in the organic diisocyanate are too few, the mechanical strength and wear resistance of the resulting polyurethane tend to decrease. Conversely, if the isocyanate groups in the organic diisocyanate are too many, the productivity of the polyurethane and the storage stability of the polyurethane raw material tend to decrease.

[0105] From the perspective of obtaining a polished layer with particularly excellent planarity and low scratch resistance, the proportion of nitrogen atoms from isocyanate groups in the polyurethane is preferably 4.8 to 7.5% by mass, more preferably 5.0 to 7.3% by mass, and particularly preferably 5.2 to 7.1% by mass. If the proportion of nitrogen atoms from isocyanate groups is too low, there is a tendency for the hardness of the resulting polished layer to decrease.

[0106] Furthermore, the polyurethane used as the material for forming the polishing layer is preferably thermoplastic polyurethane, considering the possibility of obtaining a polishing layer with high hardness and excellent planarization. It should be noted that thermoplasticity refers to the characteristic of being able to be melted and shaped through heating processes such as extrusion molding, injection molding, calendering, and 3D printing. Such thermoplastic polyurethane can be manufactured using polyurethane raw materials containing polymeric diols, organic diisocyanates, and chain extenders, and using known polyurethane manufacturing methods such as prepolymerization and one-step processes. From the perspective of excellent productivity, a method in which the polyurethane raw material is melt-blended and melt-polymerized under substantially solvent-free conditions is particularly preferred, and a method using a multi-screw extruder for continuous melt polymerization is even more preferred.

[0107] Furthermore, the polishing layer is preferably a non-foamed structure (non-porous). From the perspective of maintaining high hardness and exhibiting superior planarization, a non-foamed polishing layer is preferred. Additionally, since the surface of a non-foamed polishing layer does not expose pores, abrasive particles in the slurry do not agglomerate or aggregate within the pores, thus reducing the likelihood of scratches; this is also a preferred feature. Furthermore, compared to a foamed polishing layer, a non-foamed polishing layer has a lower wear rate and therefore a longer lifespan; this is also a preferred feature.

[0108] The manufacturing method of the polishing layer is not particularly limited. For example, a known sheet-forming method can be used to form a sheet from a polymeric material composition for the polishing layer, wherein conventionally used additives for polishing layers are incorporated into the polymeric material used to form the polishing layer as needed. Specifically, a method can be used to melt-extrude the polymeric material composition for the polishing layer into a sheet using an extruder such as a single-screw extruder or a twin-screw extruder equipped with a T-die. Alternatively, the sheet can be manufactured by molding the aforementioned material composition for the polishing layer into a block and then slicing the block. The composition of the polymeric material composition for the polishing layer is not particularly limited. Specifically, the polymeric material composition preferably contains 50% by mass or more of the polymeric material, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and especially preferably 99% by mass or more. That is, when the polymeric material composition contains additives, it is preferably 50% by mass or less, more preferably 20% by mass or less, particularly preferably 10% by mass or less, and especially preferably 1% by mass or less.

[0109] Then, the obtained sheet is adjusted to the desired thickness by grinding or the like, and shaped into a circle by cutting, punching, or slitting, thereby obtaining a polishing layer sheet. Then, one side of the circular polishing layer sheet is used as a polishing surface, and radial grooves, including at least two line segment grooves extending from the central region to the peripheral region of the polishing surface, and spiral grooves or concentric circular grooves formed from the central region to the peripheral region are provided as described above, thereby obtaining the polishing layer used in the polishing pad of this embodiment.

[0110] In the case of such a polished layer, for example, in the case of a polished layer comprising a non-foamed thermoplastic polyurethane, the preferred density is 1.0 g / cm³. 3 The above, and more preferably, is 1.1 g / cm³. 3 The above, and especially preferred, value is 1.2 g / cm³. 3 The above points are relevant. When the density of the polishing layer containing non-foamed thermoplastic polyurethane is too low, there is a tendency for the polishing layer to become too soft, thereby reducing the polishing speed and polishing uniformity.

[0111] In addition, when the D hardness of the polishing layer is 45-90, further 50-88, especially 55-87, and particularly 60-86, the planarization is high, resulting in excellent polishing uniformity. Moreover, it is also excellent in suppressing the formation of scratches on the surface of the polished material. From this point of view, it is preferred.

[0112] The method for forming the radial, spiral, or concentric grooves on the polished surface is not particularly limited. Specifically, examples include: forming grooves by cutting one side of the polishing layer sheet; forming grooves by pressing a heated mold and metal wire into one side of the polishing layer sheet and then melting or volatilizing the polymer; forming grooves by laser processing one side of the polishing layer sheet to decompose or volatilize the polymer; and forming a polishing layer sheet with a grooved polished surface using a mold with pre-formed protrusions for forming grooves. From the perspective of superior productivity, the cutting method or the transfer method is preferred, and particularly from the perspective of superior processing accuracy, the cutting method is preferred. The thickness of the polishing layer is preferably 0.4 to 5.0 mm, more preferably about 0.6 to 4.5 mm.

[0113] As explained above, a polishing layer comprising a polishing pad can be manufactured. For the polishing pad of this embodiment, the polishing layer thus manufactured can be used directly as a single-layer polishing pad, or it can be used as a polishing pad with a stacked structure of two or more layers, having buffer layers, support layers, or other layers stacked on the surface of the polishing layer opposite to the polishing surface.

[0114] Figure 5 This is a partial side view of polishing pad 10 and polishing pad 20. (Refer to...) Figure 5 In polishing pads 10 and 20, a buffer layer 7 is laminated between the anti-polishing surface of polishing layer 1 or polishing layer 11 (which is opposite to the polishing surface F) and an adhesive layer 6. This laminated structure with a buffer layer is particularly preferred from the perspective of easily improving the overall polishing uniformity within the surface. When the polishing pad has a laminated structure, the buffer layer and the support layer can be laminated on the opposite side of the polishing surface of the polishing layer via an adhesive or bonding agent.

[0115] The C-hardness of the cushioning layer is preferably 20 to 70. Furthermore, the raw material of the cushioning layer is not particularly limited; examples include sheets made by impregnating resin into nonwoven fabric, sheets of elastomers with non-foamed or foamed structures, etc. Specifically, examples include: composites made by impregnating polyurethane into nonwoven fabric; rubbers such as natural rubber, nitrile rubber, polybutadiene rubber, and silicone rubber; thermoplastic elastomers such as polyester thermoplastic elastomers, polyamide thermoplastic elastomers, and fluoropolymer thermoplastic elastomers; foamed plastics; sheets of polyurethane, etc. Among these, sheets of polyurethane with a foamed structure are particularly preferred from the perspective of easily obtaining preferred softness.

[0116] The polishing pad described above in this embodiment is preferably used in CMP. Next, an embodiment of a CMP using the polishing pad 10 of this embodiment will be described.

[0117] In CMP, for example, using features such as Figure 6 The CMP device 100 shown comprises a circular rotating platform 101, a slurry supply nozzle 102, a support plate 103, and a pad adjuster 104. A polishing pad 10 is attached to the surface of the rotating platform 101 using double-sided adhesive sheets or the like. The support plate 103 supports the material 50 to be polished.

[0118] In the CMP apparatus 100, the rotary platform 101 is rotated, for example, in the direction indicated by the arrow, by a motor (omitted in the figure). Additionally, the tray 103, while pressing the polished surface of the polished material 50 against the polishing surface of the polishing pad 10, is rotated, for example, in the direction indicated by the arrow, by a motor (omitted in the figure). The pad adjuster 104 rotates, for example, in the direction indicated by the arrow. When the diameter of the pad adjuster 104 is smaller than the diameter of the polished material 50, the pad adjuster 104 is oscillated radially in the rotary platform 101 to ensure that the entire area of ​​the polishing pad in contact with the polished material achieves a roughness suitable for polishing.

[0119] When using an unused polishing pad, a conditioning process called "run-in" is typically performed before polishing the material. This running-in process is used to finely roughen the polishing surface of the polishing pad to create a roughness suitable for polishing. Specifically, the surface of the polishing pad 10 is adjusted by pressing a pad conditioner 104 for CMP while water flows over the surface of the polishing pad 10, which is fixed to and rotated on a rotating platform 101. Examples of pad conditioners include those that fix diamond particles to the surface of a carrier by means of nickel electrodeposition.

[0120] Then, after the break-in period, polishing of the surface of the material to be polished begins. During polishing, slurry is supplied from the slurry supply nozzle to the surface of the rotating polishing pad. The slurry may contain, for example, liquid media such as water or oil; polishing agents such as silica, alumina, cerium oxide, zirconium oxide, and silicon carbide; and alkalis, acids, surfactants, oxidants, reducing agents, and chelating agents. Additionally, during CMP, lubricants and coolants may be used in combination with the slurry as needed. The material to be polished, fixed to the tray and rotating, is then pressed onto the polishing pad, which is thoroughly coated with slurry. Polishing continues until the desired flatness and polishing amount are achieved. The final finish quality can be affected by adjusting the pressing pressure applied during polishing and the relative speed of the rotating platform and the tray.

[0121] Polishing conditions are not particularly limited. For efficient polishing, the rotation speed of both the platform and the material being polished is preferably low, below 300 rpm. To avoid scratches after polishing, the pressure applied to the material being polished to press it against the polishing pad is preferably below 150 kPa. Furthermore, during polishing, it is preferable to continuously or intermittently supply slurry to the polishing pad in a manner that ensures the slurry is evenly distributed across the polishing surface.

[0122] After polishing, the material is thoroughly cleaned and then dried using a rotary dryer or similar device to remove any remaining water droplets. This results in a smooth surface after polishing.

[0123] This CMP embodiment is preferably used for polishing in the manufacturing processes of various semiconductor devices, MEMS (Micro ElectroMechanical Systems), etc. Examples of materials to be polished include: semiconductor substrates such as silicon, silicon carbide, gallium nitride, gallium arsenide, zinc oxide, sapphire, germanium, and diamond; insulating films such as silicon oxide films, silicon nitride films, and low-k films formed on wiring boards having given wiring; wiring materials such as copper, aluminum, and tungsten; glass, crystal, optical substrates, and hard disks. The polishing pad of this embodiment is particularly preferred for polishing insulating films and wiring materials formed on semiconductor substrates.

[0124] Example

[0125] The present invention will now be described in more detail through embodiments. It should be noted that the scope of the present invention is not limited to these embodiments.

[0126] [Manufacturing Example 1]

[0127] Polytetramethylene glycol (PTMG) with a number-average molecular weight of 850, polyethylene glycol (PEG) with a number-average molecular weight of 600, 1,4-butanediol (BD), and 4,4'-diphenylmethane diisocyanate (MDI) were blended in a mass ratio of PTMG:PEG:BD:MDI of 24.6:11.6:13.8:50.0 and continuously fed into a coaxially rotating twin-screw extruder via a metering pump for continuous melt polymerization of thermoplastic polyurethane. The polymerized molten thermoplastic polyurethane was then continuously extruded into water in a filament and cut into granules by a granulator. These granules were dehumidified and dried at 70°C for 20 hours before being fed into a single-screw extruder and extruded through a T-die to form sheets. The surface of the obtained sheet is then ground to form a uniform sheet with a thickness of 2.0 mm, which is then cut into a circular shape with a diameter of 740 mm, thus obtaining a polishing layer sheet as a non-foamed material. Based on JIS K 7311, the D hardness of the polishing layer sheet was measured to be 62 at a measurement temperature of 25°C.

[0128] [Manufacturing Example 2]

[0129] In Manufacturing Example 1, a polyurethane raw material formulated with polytetramethylene glycol (number average molecular weight 850), 3-methyl-1,5-pentanediol (MPD), 1,4-butanediol, and 4,4'-diphenylmethane diisocyanate in a mass ratio of PTMG:MPD:BD:MDI of 12.5:5.7:17.5:64.3 was used instead of a polyurethane raw material formulated in a mass ratio of PTMG:PEG:BD:MDI of 24.6:11.6:13.8:50.0. Otherwise, thermoplastic polyurethane particles were obtained in the same manner as in Manufacturing Example 1. Then, a polishing layer sheet as a non-foamed material was obtained in the same manner as in Manufacturing Example 1. Based on JIS K 7311, the D hardness of the polishing layer sheet, measured at a temperature of 25°C, was 86.

[0130] [Manufacturing Example 3]

[0131] In Manufacturing Example 1, a polyurethane raw material formulated with polytetramethylene glycol (number average molecular weight 850), polyethylene glycol (number average molecular weight 600), 1,9-nonanediol (number average molecular weight ND), and 4,4'-diphenylmethane diisocyanate in a mass ratio of PTMG:PEG:ND:MDI of 32.2:5.7:19.6:42.5 was used instead of a polyurethane raw material formulated with a mass ratio of PTMG:PEG:ND:MDI of 24.6:11.6:13.8:50.0. Otherwise, thermoplastic polyurethane particles were obtained in the same manner as in Manufacturing Example 1. Then, a polishing layer sheet as a non-foamed material was obtained in the same manner as in Manufacturing Example 1. Based on JIS K 7311, the D hardness of the polishing layer sheet, measured at a temperature of 25°C, was 56.

[0132] [Manufacturing Example 4]

[0133] In Manufacturing Example 1, a polyurethane raw material formulated with polytetramethylene glycol (number average molecular weight 850), polyethylene glycol (number average molecular weight 600), 3-methyl-1,5-pentanediol (MPD), 1,9-nonanediol, and 4,4'-diphenylmethane diisocyanate in a mass ratio of PTMG:PEG:MPD:ND:MDI of 36.1:6.4:1.3:15.7:40.5 was used instead of a polyurethane raw material formulated with a mass ratio of PTMG:PEG:BD:MDI of 24.6:11.6:13.8:50.0. Otherwise, thermoplastic polyurethane particles were obtained in the same manner as in Manufacturing Example 1. Then, a polishing layer sheet as a non-foamed material was obtained in the same manner as in Manufacturing Example 1. Based on JIS K 7311, the D hardness of the polishing layer sheet, measured at a temperature of 25°C, was 46.

[0134] [Examples 1-25 and Comparative Examples 1-13]

[0135] By machining, grooves with patterns having the shapes described in Tables 1 and 2 were formed on one side of the polished layer sheet with a D hardness of 62 obtained in Manufacturing Example 1.

[0136] It should be noted that in Examples 12 and 4, concentric grooves were formed with the center of the concentric circle offset from the center of the polished surface by 15 mm. In this case, the center of the concentric groove is located at a distance of approximately 4% of the radius from the center of the polished surface. Furthermore, the center of the radial groove in Example 13 coincides with the center of the concentric groove.

[0137] Furthermore, for the concentric circular grooves, spiral grooves, lattice grooves, and segmental grooves forming radial grooves in various embodiments, the inclined surfaces of the grooves are chamfered at an angle ranging from 35 to 80 degrees, as needed. Additionally, the inclined surfaces of the inverted trapezoidal grooves are also formed at an angle ranging from 35 to 80 degrees. By changing the angle of the inclined surfaces, the cross-sectional area changes.

[0138] Based on 200x scanning electron microscopy (SEM) images of cross-sections, the width and cross-sectional area of ​​each groove—concentric circular grooves, spiral grooves, lattice grooves, and segmental grooves forming radial grooves—were measured. Specifically, cross-sections of the grooves in each polished layer were photographed at 18 arbitrary locations, the width of the grooves in each image was measured, and the cross-sectional area was further measured through image processing to calculate their average value. Furthermore, for the average groove spacing P of the concentric circular grooves, spiral grooves, and lattice grooves, measurements were taken at 8 arbitrarily selected locations in the region of the polished surface in contact with the silicon wafer using a scale magnifying glass, and the average value was taken as the average groove spacing P. Additionally, the depth of each groove was determined by averaging the measured values ​​at 8 arbitrarily selected locations in the region of contact with the silicon wafer using a depth gauge "E-DP2J" manufactured by Nakamura Manufacturing Co., Ltd.

[0139] Then, a multi-layer polishing pad was fabricated by attaching the buffer layer to the back side of the polishing layer opposite to the polishing surface using a double-sided adhesive sheet. As the buffer layer, a 0.8 mm thick polyurethane foam sheet manufactured by Inoac Corporation, "PORON H48", was used. The polishing properties of the resulting polishing pad were then evaluated using the following evaluation method.

[0140] Polishing speed

[0141] The obtained polishing pad was installed in the polishing apparatus "FREX-300" manufactured by Ebara Manufacturing Co., Ltd. Then, a slurry "HS-8005" manufactured by Hitachi Chemical Co., Ltd. was prepared by diluting and adjusting it to 10 times. Under the conditions of platen speed of 100 rpm, polishing head speed of 99 rpm, and polishing pressure of 30.0 kPa, the slurry was fed to the polishing surface of the polishing pad at a rate of 200 mL / min, and a 12-inch diameter silicon wafer with a silicon oxide film with a thickness of 2000 nm on the surface was polished for 60 seconds.

[0142] Then, using a pad conditioner (Allied Material diamond dresser (diamond model #100 Blocky, base diameter 19cm)), the surface of the polishing pad was adjusted for 30 seconds while pure water was flowing through it at a rate of 150 mL / min, with the dresser speed at 70 rpm, the polishing pad speed at 100 rpm, and the dresser load at 20 N. Then, another silicon wafer was polished again, with further adjustment for 30 seconds. After 60 seconds of polishing, the polishing pad was adjusted for 30 seconds. Then, another silicon wafer was polished again, with further adjustment for 30 seconds. Ten silicon wafers were polished in this manner.

[0143] Then, the thickness of the silicon oxide film before and after polishing was measured at 49 points on the wafer surface of the 10th polished silicon wafer, and the polishing rate (nm / min) at each point was calculated. Specifically, the average polishing rate at the 49 points was taken as the polishing rate.

[0144] Then, using the polishing speed of 1050 nm / min achievable with the existing general groove shape as a benchmark, the improvement rate of polishing speed for each embodiment was calculated using the following formula.

[0145] Improvement rate of polishing speed (%) = Polishing speed ÷ 1050 × 100

[0146] The results are shown in Tables 1 and 2 below.

[0147]

[0148]

[0149] The polishing speeds of the polishing pads obtained in Examples 1 to 25 of the present invention, as shown in Table 1, are all high. On the other hand, the polishing speeds of the polishing pads obtained in Comparative Examples 1 to 13, as shown in Table 2, are all low. Furthermore, referring to Table 1, the following conditions are met: 0.25 ≤ Sb / Sa ≤ 0.85 and 0.2 ≤ {Wb}. 2 The polishing speed of the polishing pads obtained in Examples 1 to 21 with / (P×Wa)}×100≤21.0 is particularly high.

[0150] <The Influence of Sb / Sa on Polishing Uniformity>

[0151] Twelve polishing pads with different Sb / Sa ratios were selected. Multiple silicon wafers were then polished using the same method as for measuring polishing speed. The polishing uniformity of polishing pads polished to a depth 50% lower than the groove depth of the annular grooves of the unused polishing layer was then evaluated, as described below.

[0152] The thickness of the silicon oxide film before and after polishing was measured at 49 points within the wafer surface (3 mm in the ineffective edge region) when the depth of the annular groove in the polishing layer was reduced by 50%. The polishing rate (nm / min) at each point was determined. Then, the average value and standard deviation 1σ of the polishing rate at the 49 points were calculated, and the coefficient of variation (unit: %) was determined based on the average value and standard deviation 1σ. The smaller the coefficient of variation, the better the polishing uniformity. The evaluation results of Sb / Sa, polishing rate, and polishing uniformity are shown in Table 3 below.

[0153] Table 3

[0154]

[0155] As shown in Table 3, the polishing uniformity variation coefficients of Examples 4, 2, 10, 16, and 3, which satisfy 0.44≤Sb / Sa≤0.80, are as low as 3.3%, exhibiting particularly excellent polishing uniformity and high polishing speed.

[0156] [Examples 26-28]

[0157] Polishing layer sheets with a D hardness of 86 obtained in Manufacturing Example 2, polishing layer sheets with a D hardness of 56 obtained in Manufacturing Example 3, and polishing layer sheets with a D hardness of 49 obtained in Manufacturing Example 4 were used respectively. Otherwise, polishing pads were manufactured in the same manner as in Example 10 (Examples 26, 27, 28). Then, the effect of the D hardness of the polishing layer on the polishing uniformity was investigated.

[0158] The evaluation results of the effect of the D hardness of the polished layer on the polishing uniformity are shown in Table 3.

[0159] Table 4

[0160]

[0161] Referring to Table 4, it can be seen that the polishing pads using polishing layers from Examples 10, 26, and 27 (with JIS D hardness in the range of 56-86) exhibit significantly lower coefficients of variation in polishing uniformity compared to the polishing layer of Example 28 (with JIS D hardness of 46), demonstrating particularly superior polishing uniformity.

[0162] [Examples 29-39 and Comparative Examples 14-24]

[0163] A groove with the pattern described in Tables 5 and 6 was formed on one side of the polished layer sheet obtained in Manufacturing Example 1, i.e., the polished surface, by machining. It should be noted that in Examples 30 and 32, concentric circular grooves were formed with the center of the concentric circle offset from the center of the polished surface by 15 mm. In this case, the center of the concentric circular groove is located at a distance of approximately 4% of the radius from the center of the polished surface. Furthermore, the center of the radial groove coincides with the center of the concentric circular groove. Additionally, the grooves in each embodiment are Y-shaped, trapezoidal, or rectangular with chamfered corners. Then, the groove width, cross-sectional area, groove spacing, and depth of each groove were measured in the same manner as described above.

[0164] Then, a multi-layer polishing pad was fabricated by attaching the buffer layer to the back side of the polishing layer opposite to the polishing surface using a double-sided adhesive sheet. As the buffer layer, a 0.8 mm thick polyurethane foam sheet manufactured by Inoac Corporation, "PORON H48", was used. The polishing properties of the resulting polishing pad were then evaluated using the following evaluation method.

[0165] Polishing speed

[0166] The obtained polishing pad was installed in the polishing apparatus "FREX-300" manufactured by Ebara Manufacturing Co., Ltd. Then, a slurry "SEMI-SPERSE25" manufactured by Cabot Microelectronics was prepared by diluting and adjusting it to 2 times. Under the conditions of platen speed of 100 rpm, polishing head speed of 99 rpm, and polishing pressure of 20.0 kPa, the slurry was fed to the polishing surface of the polishing pad at a rate of 200 mL / min, and a 12-inch diameter silicon wafer with a silicon oxide film with a thickness of 2000 nm on the surface was polished for 60 seconds.

[0167] Then, using a pad conditioner (Allied Material diamond dresser (diamond model #100 Blocky, base diameter 19cm)), the surface of the polishing pad was adjusted for 30 seconds while pure water was flowing through it at a rate of 150 mL / min, with the dresser speed at 70 rpm, the polishing pad speed at 100 rpm, and the dresser load at 20 N. Then, another silicon wafer was polished again, with further adjustment for 30 seconds. After 60 seconds of polishing, the polishing pad was adjusted for 30 seconds. Then, another silicon wafer was polished again, with further adjustment for 30 seconds. Ten silicon wafers were polished in this manner.

[0168] Then, the thickness of the silicon oxide film before and after polishing was measured at 49 points on the wafer surface of the 10th polished silicon wafer, and the polishing rate at each point was determined. Specifically, the average polishing speed of the 49 points is taken as the polishing speed.

[0169] In addition, the polishing speed achievable using existing general groove shapes will be increased. As a benchmark, the improvement rate of polishing speed for each embodiment was calculated using the following formula.

[0170] Improvement rate of polishing speed (%) = Polishing speed ÷ 2400 × 100

[0171] The results are shown in Tables 5 and 6.

[0172]

[0173]

[0174] The polishing speeds of the polishing pads obtained in Examples 29-39 of the present invention, as shown in Table 5, are all high. On the other hand, the polishing speeds of the polishing pads obtained in Comparative Examples 14-24, as shown in Table 6, are all low. It should be noted that, referring to Table 5, the polishing speeds are those satisfying 0.1 ≤ Wb / Wa < 1.0 and 0.2 ≤ {Wb}. 2 The polishing speed of the polishing pads obtained in Examples 28 to 37 with / (P×Wa)}×100≤10 is particularly high.

Claims

1. A polishing pad comprising a polishing layer having a circular polishing surface, wherein, The polished surface has a central region extending from the center of the polished surface with a radius of 0 to 10%, and a peripheral region extending with a radius of 90 to 100%. The polished layer has at least one spiral groove extending from the central region to the peripheral region, or a concentric circular groove formed by a plurality of annular grooves arranged in a concentric circle, and also has radial grooves formed by at least two line segment grooves extending from the central region to the peripheral region. The center of the spiral groove, the center of the concentric circular groove, and the center of the radial groove are located in the central region. The linear groove has an average length that is 30-65% of the radius of the polished surface, and has a first end at a distance of 5-10% of the radius of the polished surface from the center of the radial groove, and a second end at a distance of 35-70%. Cross-sectional area Sa (mm 2 ) and cross-sectional area Sb (mm 2 The condition 0.1 ≤ Sb / Sa < 1.0 is satisfied, where Sa is the average cross-sectional area of ​​the segmental groove in the direction perpendicular to the length direction, and Sb is the average cross-sectional area of ​​the spiral groove or the concentric circular groove in the direction perpendicular to the tangent direction.

2. The polishing pad according to claim 1, wherein 0.25≤Sb / Sa≤0.

85.

3. The polishing pad according to claim 1, wherein 0.44≤Sb / Sa≤0.

80.

4. The polishing pad according to any one of claims 1 to 3, wherein, The groove width Wa (mm) and the groove width Wb (mm) satisfy 0.1≤Wb / Wa<1.0, the groove width Wa is the average value of the width of the linear groove, and the groove width Wb is the average value of the width of the spiral groove or the concentric circular groove.

5. The polishing pad according to any one of claims 1 to 3, wherein, The groove width Wb (mm) and the average groove spacing P (mm) of the spiral groove or the concentric circular groove satisfy 0.02≤Wb / P≤0.25, where the groove width Wb is the average width of the spiral groove or the concentric circular groove.

6. The polishing pad according to any one of claims 1 to 3, wherein, The groove width Wa (mm), the groove width Wb (mm), and the average groove spacing P (mm) of the spiral groove or the concentric circular groove satisfy 0.2 ≤ {Wb} 2 / (P×Wa)}×100≤25, where Wa is the average width of the line segment groove, and Wb is the average width of the spiral groove or the concentric circle groove.

7. The polishing pad according to any one of claims 1 to 3, wherein, The polished layer includes the spiral grooves.

8. The polishing pad according to any one of claims 1 to 3, wherein, The polished layer includes the concentric circular grooves.

9. The polishing pad according to any one of claims 1 to 3, wherein, The polishing layer comprises thermoplastic polyurethane.

10. The polishing pad according to any one of claims 1 to 3, wherein, The polishing layer is a non-foamed material.

11. The polishing pad according to any one of claims 1 to 3, wherein, The JIS D hardness of the polished layer is 45~90.

12. The polishing pad according to any one of claims 1 to 3, wherein, The density of the polished layer is 1.00~1.20 g / cm³. 3 .

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