Polishing Pad

Abstract

This polishing pad has a polishing layer having a circular polishing surface, and is also provided with a spiral groove or concentric circular grooves consisting of a plurality of annular grooves arranged in concentric circles and formed spanning from a central region of the polishing surface to a circumferential edge region, and radiating grooves consisting of line segment grooves extending from the central region toward the circumferential edge region. The line segment grooves have first end sections in a region at a distance 5-10% of the radius of the polishing surface from the center of the radiating grooves and have second end sections in a region at a distance 35-70% of the radius of the polishing surface from the center of the radiating grooves. The line segment grooves have an average length that is a 30-65% proportion of the radius of the polishing surface. A cross-sectional area Sa (mm2) of the line segment grooves and a cross-sectional area Sb (mm2) of the spiral groove or concentric circular grooves satisfy the formula 0.1 ≤ Sb / Sa < 1.0.

Description

[Technical field]

[0001] The present invention relates to a polishing pad preferably used for chemical mechanical polishing (CMP). [Background technology]

[0002] Conventionally, chemical mechanical polishing (CMP) has been used to polish substrate materials such as semiconductors and silicon wafers, and glass, which is the material for hard disks, liquid crystal displays, and lenses, to a mirror finish, and to smooth out irregularities caused by insulating and metal films in the manufacturing process of semiconductor devices. In this method, a polishing material is pressed against a polishing pad while a polishing slurry (hereinafter simply referred to as slurry) is dropped onto the polishing surface of the polishing pad.

[0003] Polishing pads for CMP have grooves such as spiral grooves, concentric grooves, lattice grooves, radial grooves, etc. formed on them for the purposes of retaining slurry evenly on the polishing surface, discharging polishing debris, and preventing damage due to adhesion of the material to be polished.

[0004] For example, the following Patent Document 1 discloses a polishing pad for semiconductor wafers in which a plurality of radial grooves extending from the center to the periphery are formed in the portion where the central portion of the wafer comes into contact during polishing, and a plurality of circular grooves concentric with the polishing pad are formed in at least the portion where the peripheral portion of the wafer comes into contact, and discloses that the width of the portion where the radial grooves are formed is approximately 1 / 2 the diameter of the wafer.

[0005] Furthermore, for example, Patent Document 2 below discloses a polishing pad in which radial grooves and concentric grooves are open on the polishing side surface of the polishing layer so as to share a common center and intersect with each other, and where the intersections between the radial grooves and the concentric grooves belong to the radial grooves, and the radial grooves and the concentric grooves satisfy condition (A) that the proportion of the area (s1) of the radial groove to the sum (s1+s2) of the area (s1) of the radial grooves is 8 to 17%, and condition (B) that the proportion of the sum (s1+s2) of the area (s1) of the radial grooves to the area (S) of the polishing side surface is 18 to 25%.

[0006] For example, the following Patent Document 3 discloses a polishing pad having a polishing layer including a center, a periphery, a radius extending from the center to the periphery, and a polishing track surrounding the center and intersecting the radius, and a plurality of supply grooves (δ) intersecting the radius, with land areas between the supply grooves (δ) for planarizing the polished material. The polishing pad has an average supply cross-sectional area (δ a ), and at least one radial drainage groove (ρ) in the polishing layer intersecting the plurality of supply grooves (δ) for allowing polishing fluid to flow from the plurality of supply grooves (δ) to the at least one radial drainage groove (ρ). The polishing pad has a radial drainage groove (ρ) having an average drainage cross-sectional area (ρ a ) and the average cross-sectional area of ​​the radial drainage grooves (ρ a ) is 2×δ a ≦ρ a ≦8×δ a , (0.15)n f ×δ a ≦n r ×ρ a ≦(0.35)n f ×δ a (In the formula, (n r ) represents the number of radial grooves, (n f ) represents the number of supply grooves) according to the average supply cross-sectional area (δ a ), with radial drainage grooves (ρ) extending through the polishing track to facilitate removal of polishing debris under at least one of a semiconductor substrate, an optical substrate, and a magnetic substrate, through the polishing track, and over the polishing track to the periphery of the polishing pad during rotation of the polishing pad.

[0007] Also, for example, Patent Document 4 listed below discloses a polishing pad having a polishing layer with a central rotation center and a central track having a center of arrangement spaced from the rotation center; annular grooves in which a plurality of annular grooves are arranged with the center as a concentric center; and grooves extending in radial directions, with a plurality of cross points provided on the central track.

[0008] Also, for example, Patent Document 5 below discloses a polishing pad which has a first region in which radially extending grooves and annular grooves that do not extend to the center of the polishing layer exist together, and a second region in which only the annular groove exists, and the radius of the first region is 30 to 70% of the radius of the polishing pad. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2000-237950 A [Patent Document 2] JP 2011-177884 A [Patent Document 3] JP 2017-208530 A [Patent Document 4] TW M459065U1 publication [Patent Document 5] TW I548484 publication Summary of the Invention [Problem to be solved by the invention]

[0010] In CMP, there is a demand for a polishing pad that can realize a higher removal rate. An object of the present invention is to provide a polishing pad for realizing a high removal rate in CMP. [Means for solving the problem]

[0011] One aspect of the present invention is a polishing pad including a polishing layer having a circular polishing surface. The polishing surface has a central region that is in the range of 0-10% of the radius from the center of the polishing surface, and a peripheral region that is in the range of 90-100%. The polishing layer has at least one spiral groove or a concentric groove consisting of a plurality of annular grooves arranged concentrically, which are arranged from the central region to the peripheral region, and further has a radial groove consisting of at least two linear grooves extending from the central region to the peripheral region. The center of the spiral groove, the center of the concentric groove, and the center of the radial groove are present in the central region, and the linear groove has an average length that is 30-65% of the radius of the polishing surface, and has a first end in an area that is 5-10% of the radius of the polishing surface from the center of the radial groove, and a second end in an area that is 35-70% of the radius of the polishing surface. The average cross-sectional area Sa (mm 2 ) and the cross-sectional area Sb (mm 2 ) and the polishing pad satisfies 0.1≦Sb / Sa<1.0.

[0012] Here, the polishing surface means the surface of the polishing layer that contacts the material to be polished. Also, the central region means, for example, a circular region R1 indicated by dots ranging from 0 to 10% of the radius from the center G of the circular polishing surface, as shown in FIG. 7. Also, the peripheral region means a region ranging from 90 to 100% of the radius from the center of the circular polishing surface, more specifically, a band-like region R2 indicated by dots along the periphery of the circle ranging from 90 to 100% of the radius.

[0013] Moreover, the term "linear groove" means that the linear groove does not reach the periphery of the polishing surface, and has both ends within the polishing surface. Moreover, the term "spiral groove" means at least one spiral groove having a spiral center in the central region of the polishing surface. Moreover, the term "concentric groove" means a groove consisting of a plurality of annular grooves arranged concentrically, with a common center in the central region of the polishing surface. Moreover, the term "a spiral groove or a concentric groove is arranged from the central region to the peripheral region" means that at least one spiral groove or a plurality of annular grooves arranged concentrically are formed evenly from the central region to the peripheral region of the polishing surface. Specifically, in the case of a concentric groove, it means that the groove closest to the center passes through the central region, and the groove at the outermost periphery passes through the peripheral region. Moreover, in the case of a spiral groove, it means that the start point of the spiral groove is in the central region, and the end point of the spiral groove is in the peripheral region. The polishing region means the region of the polishing surface that comes into contact with the surface of the workpiece, such as a silicon wafer, and polishes the workpiece.

[0014] In such a polishing pad, the linear grooves prevent the slurry that is dropped onto the polishing surface and accumulated near the central region from leaking out of the system from the peripheral edge of the polishing surface, while supplying the slurry appropriately to the spiral grooves and concentric grooves formed from the central region to the peripheral region. As a result, the slurry is efficiently supplied to the polishing region, thereby achieving a high polishing rate.

[0015] In addition, it is preferable for the polishing pad to satisfy 0.25≦Sb / Sa≦0.85, and further preferably 0.44≦Sb / Sa≦0.80, since a higher polishing rate can be obtained and excellent polishing uniformity can be achieved within the polished surface of the material to be polished.

[0016] In addition, it is preferable that the groove width Wa (mm), which is the average width of the linear grooves, and the groove width Wb (mm), which is the average width of the spiral grooves or concentric grooves, of the polishing pad satisfy 0.1≦Wb / Wa<1.0. In such a case, the slurry is evenly held in the polishing area, thereby realizing a higher polishing rate.

[0017] In addition, it is preferable that the groove width Wb (mm), which is the average width of the spiral groove or the concentric groove, and the average groove pitch P (mm) of the spiral groove or the concentric groove satisfy 0.02≦Wb / P≦0.25. In such a case, the area of ​​the land area that contacts the polished material can be sufficiently secured, and a sufficient amount of slurry can be supplied to the land area, thereby realizing a higher polishing speed. Note that the groove pitch P means the average of the sum of the groove interval and groove width in each adjacent spiral revolution in the case of a spiral groove, or in each adjacent annular groove in the case of a concentric groove.

[0018] The polishing pad has a groove width Wa (mm) which is the average width of the linear grooves, a groove width Wb (mm) which is the average width of the spiral grooves or concentric grooves, and an average groove pitch P (mm) of the spiral grooves or concentric grooves which are within the range of 0.2≦{Wb 2 It is preferable that the relationship of {P×Wa / (P×Wa)}×100≦25 is satisfied. In such a case, the slurry is quickly supplied to the polishing region and the slurry is sufficiently held between the polishing surface and the polished surface of the workpiece, thereby realizing a higher polishing rate.

[0019] In addition, in the polishing pad, it is preferable that the polishing layer contains a thermoplastic polyurethane, which is excellent in terms of low scratch resistance and easy molding, and it is preferable that the polishing layer is a non-foamed material, which is excellent in terms of stability of the polishing rate and easy molding. Effect of the Invention

[0020] According to the present invention, a polishing pad that can easily realize an increase in the polishing rate of CMP is obtained. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic plan view of the polishing surface side of a polishing layer 1 of a polishing pad 10 having a spiral groove according to an embodiment. [Diagram 2] FIG. 2 is a schematic plan view of the polishing surface side of a polishing layer 11 of a polishing pad 20 having concentric grooves according to an embodiment. [Figure 3A]FIG. 3A is a schematic diagram of a cross section of a spiral groove or a concentric groove taken in a direction perpendicular to the tangential direction. [Figure 3B] FIG. 3B is a schematic diagram of a cross section of a groove for explaining the angle of a slope formed by chamfering the corner portion of the groove. [Figure 3C] FIG. 3C is a schematic diagram of a cross section of a groove for explaining the angle of the slope of the groove having an inverted trapezoidal cross section. [Figure 4] FIG. 4 is a schematic diagram of a cross section of a linear groove taken in a direction perpendicular to the length direction. [Diagram 5] FIG. 5 is a partial schematic cross-sectional view of the polishing pad 10 or polishing pad 20 in the thickness direction. [Figure 6] FIG. 6 is an explanatory diagram for explaining CMP. [Figure 7] FIG. 7 is an explanatory diagram for explaining the central region and the peripheral region of the polishing surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The polishing pad of this embodiment will be described in detail with reference to the drawings.

[0023] FIG. 1 is a schematic plan view of the polishing surface of a polishing pad 10, which is an example of the polishing pad of this embodiment, including a polishing layer 1 having a circular polishing surface with one spiral groove H formed from the central region to the peripheral region and radial grooves consisting of eight linear grooves S1 to S8 extending from the central region toward the peripheral region.

[0024] Moreover, Figure 2 is a schematic plan view of the polishing surface of polishing pad 20, which is another example of the polishing pad of this embodiment, including a polishing layer 11 having a circular polishing surface with eleven annular grooves C1 to C11 arranged concentrically from the central region to the peripheral region, and radial grooves consisting of eight linear grooves S1 to S8 extending from the central region toward the peripheral region.

[0025] Fig. 7 is an explanatory diagram for explaining a central region R1 and a peripheral region R2 in a polishing pad 10. In the polishing pad 10 shown in Fig. 7, the circular region indicated by dots within a range of 0 to 10% of the radius from the center G of the circular polishing surface is the central region R1, and the region indicated by band-shaped dots along the periphery of the circle within a range of 90 to 100% of the radius from the center of the polishing surface, more specifically, 90 to 100% of the radius, is the peripheral region R2.

[0026] 5 is a partial cross-sectional schematic diagram in the thickness direction for explaining the layer structure of the polishing pad 10 or polishing pad 20. The polishing pad 10 or polishing pad 20 has a laminated structure in which a cushion layer 7 is bonded via an adhesive layer 6 to the surface opposite to the polishing surface F of the polishing layer 1, 11. The polishing pad of this embodiment is not limited to a polishing pad having such a laminated structure, and may be a single-layer polishing pad consisting of only a polishing layer having a polishing surface.

[0027] 1, in the polishing pad 10, the polishing surface of the polishing layer 1 is circular. The polishing surface is formed with one spiral groove H arranged from the central region to the peripheral region, with the center G of the polishing surface included in the central region as the spiral center. In addition, radial grooves consisting of eight linear grooves S1 to S8 extending from the central region toward the peripheral region with the center G as the radial center are formed. Thus, in the polishing pad 10, the spiral groove H and the radial groove share a common center.

[0028] 2, the polishing surface of the polishing layer 11 of the polishing pad 20 is circular. Eleven concentric annular grooves C1-C11 are formed on the polishing surface, with the center G of the polishing surface included in the central region as the common center, and are arranged from the central region to the peripheral region. Radial grooves are formed, each consisting of eight linear grooves S1-S8, which extend from the central region toward the peripheral region with the center G as the radial center. Thus, in the polishing pad 20, the annular grooves C1-C11 and the radial grooves share a common center.

[0029] In the polishing pad 10 and the polishing pad 20, the center G of the circular polishing surface, which is the center of rotation, the center of the spiral groove or the concentric groove, and the center of the radial groove are aligned. In such a case, the slurry flows more uniformly. The polishing pad of this embodiment may have an eccentric spiral groove, a concentric groove, or a radial groove, in which the center of the polishing surface and the center of the spiral groove or the concentric groove or the center of the radial groove are not aligned. In the case of having an eccentric spiral groove or a concentric groove, it is preferable because it is easy to suppress the transfer of the shape of each groove to the polished surface of the polished material such as a wafer, which is caused by excessive polishing along each groove.

[0030] The diameter of the circular polishing surface is the diameter of a polishing surface of a general circular polishing pad used in CMP, and is preferably about 500 to 780 mm, for example. Accordingly, the radius of the circular polishing surface is preferably about 250 to 390 mm, for example.

[0031] In the polishing pad 10 or 20, the linear grooves S1 to S8 and the portions where the spiral groove H or the concentric annular grooves C1 to C11 are not formed become land areas that come into contact with the polished surface of the workpiece and perform polishing. The polishing pad 10 and the polishing pad 20 are similar polishing pads, except for the spiral groove H and the concentric annular grooves C1 to C11. The polishing pad 10 shown in FIG. 1 has a spiral groove H formed therein, and the polishing pad shown in FIG. 2 has a spiral groove H formed therein. Do 20 The polishing pad of this embodiment may have a groove formed thereon that is a combination of a spiral groove and a concentric annular groove.

[0032] As described above, the polishing pad of this embodiment has spiral grooves or concentric grooves formed from the central region to the peripheral region of the polishing surface.

[0033] In this way, the spiral groove or concentric groove formed from the central region to the peripheral region of the polishing surface is preferably formed over an area of ​​at least 5 to 90% of the radius of the polishing surface from the center of the spiral or the center of the concentric circle, more preferably over an area of ​​4.5 to 95%, and particularly preferably over an area of ​​4 to 100%.

[0034] 1, in the polishing pad 10, a spiral groove H with 10 turns having a uniform groove pitch is formed in an area extending from a spiral center coinciding with a center G included in the central area of ​​the polishing surface of the polishing layer 1 to at least 5-90% of the radius of the polishing surface. A spiral with a uniform groove pitch is also called an Archimedean spiral. The spiral groove H with turns 1 to 6 intersects with the linear grooves S1 to S8 to form 41 intersections.

[0035] In the polishing layer with the spiral groove formed in this way, the starting point is preferably in an area of ​​5% radius or less, more preferably 4.5% radius or less, particularly preferably 4% radius or less from the center of the polishing surface, and the end point is preferably in an area of ​​90% radius or more, more preferably 95% radius or more, particularly preferably 100% radius, reaching the periphery. Since the spiral groove is formed in almost the entire area from the center area to the periphery area of ​​the polishing surface in this way, the slurry can be evenly distributed in the polishing area.

[0036] The spiral groove may be one spiral groove, or may be two or more spiral grooves arranged in parallel. Specifically, the number of parallel grooves in the spiral groove is preferably 1 to 16, and more preferably 1 to 10.

[0037] 2, in polishing pad 20, concentric annular grooves C1-C11 having a uniform groove pitch are formed in an area extending over at least 5-90% of the radius of the polishing surface from the center of a concentric circle coinciding with center G included in the central region of the polishing surface of polishing layer 11. Among the annular grooves C1-C11, annular grooves C2-C6 intersect with linear grooves S1-S8 to form 40 intersections.

[0038] In the polishing layer having such concentric grooves, it is preferable that the concentric grooves are formed so that the annular groove closest to the center of the polishing surface passes through an area having a radius of 5% or less, preferably a radius of 4.5% or less, and particularly a radius of 4% or less, and the outermost groove passes through an area having a radius of 90% or more, and even more preferably a radius of 95% or more.

[0039] The groove pitch, which is the distance between adjacent grooves of the spiral groove or the concentric groove, is not particularly limited, but referring to FIG. 3A, the groove pitch P (mm), which is the average distance between adjacent grooves, is preferably 1 to 15 mm, more preferably 2 to 12 mm, and particularly preferably 2 to 10 mm. If the groove pitch P of the spiral groove or the concentric groove is too large, the amount of slurry supplied from the spiral groove or the concentric groove to the land area tends to be insufficient. On the other hand, if the groove pitch P is too small, the proportion of the land area tends to be too low, and the polishing speed tends to be low.

[0040] The cross-sectional shape of the spiral groove or the concentric groove is not particularly limited. Specifically, the cross-sectional shape of the spiral groove or the concentric groove in the direction perpendicular to the tangent direction may be a quadrangular shape such as a rectangle, a square, a trapezoid, an inverted trapezoid, a triangular shape, a semicircular shape, a semi-elliptical shape, or the like, without any particular limitation. Among these, a quadrangular shape is preferred because it is excellent in processability, slurry retention, and supply stability.

[0041] In addition, in order to suppress the generation of burrs during polishing, the spiral groove or the concentric groove preferably has a cross section inclined so that the groove is inversely tapered toward the opening. Specifically, as shown in FIG. 3B, the groove is preferably so-called Y-shaped, having a tapered portion in which two corners forming a rectangular groove located on the polishing surface are chamfered so as to be inclined at a predetermined angle α, or as shown in FIG. 3C, the groove is preferably an inverted trapezoidal cross section formed so that the oblique side is inclined at a predetermined angle α with respect to the two corners forming the base angle. The angle of such inclination is not particularly limited, but is preferably 20 degrees to less than 90 degrees, further 25 to 80 degrees, and particularly 30 to 75 degrees. In particular, when the angle is 30 to 80 degrees, the generation of burrs that tend to occur at the corners of the groove during polishing is easily suppressed, and thus the decrease in polishing speed and the decrease in polishing uniformity are easily suppressed.

[0042] Also, referring to FIG. 3A, the width of the spiral groove or the concentric groove is preferably 0.1 to 4 mm, more preferably 0.2 to 2 mm, in terms of particularly excellent polishing speed and polishing uniformity, in terms of the average width Wb (mm) of each groove. The width of the spiral groove or the concentric groove is defined as follows in the cross-sectional shape when cut in a direction perpendicular to the tangent direction of the annular groove or the spiral groove. When the cross-sectional shape is rectangular or square, it is defined as the width at the polishing surface. When the cross-sectional shape is trapezoidal or inverted trapezoidal, it is defined as the average width of the lower base. When a chamfered tapered portion is formed, such as a Y-shape, it is defined as the width of the groove cross section on the polishing surface when it is assumed that the tapered portion is not formed. When the shape is triangular, semicircular, or semi-elliptical, it is defined as the width at 1 / 2 the depth.

[0043] In addition, the depth of the spiral groove or the concentric groove is preferably about 0.3 to 3.0 mm, more preferably about 0.5 to 2.5 mm, in order to ensure the supply of slurry to the polishing area sufficiently, and to suppress the deformation of the polishing pad and stabilize the polishing performance.If the spiral groove or the concentric groove is too deep, the volume of the spiral groove or the concentric groove is likely to be large, and it is necessary to supply more slurry to the polishing area during polishing, which may be undesirable in terms of cost.If the spiral groove or the concentric groove is too shallow, the volume of the spiral groove or the concentric groove is likely to be small, and the amount of slurry held in the polishing area during polishing is reduced, and the amount of slurry supplied to the land area of ​​the polishing area is reduced, which tends to reduce the polishing speed.

[0044] The cross-sectional area of ​​the spiral groove or the concentric groove is the average cross-sectional area Sb (mm 2 ) is 0.2 to 4.5 mm 2 , and even 0.3 to 4.0 mm 2 It is preferable that the cross-sectional area Sb is too large because it can ensure a sufficient supply of slurry to the polishing area. If the cross-sectional area Sb is too large, it is necessary to drip more slurry to ensure that the slurry is sufficiently distributed in the polishing area, which may be undesirable in terms of cost. If the cross-sectional area Sb is too small, the amount of slurry supplied to the polishing area tends to decrease, and the polishing speed tends to decrease. The average cross-sectional area is also the average cross-sectional area of ​​each groove.

[0045] The groove pitch P, groove width Wb, depth, and cross-sectional area Sb of the spiral grooves or concentric grooves are based on an unused polishing pad before break-in processing.

[0046] As described above, the polishing pad of this embodiment includes radial grooves consisting of at least two linear grooves extending from the central region of the polishing surface toward the peripheral region. Each linear groove has a first end in a region that is 5 to 10% of the radius of the polishing surface from the center of the radial groove. Also, a second end is in a region that is 35 to 70% of the radius of the polishing surface from the center of the radial groove. Here, the center of the radial groove means the position of the center of gravity of the first end of all the linear grooves. The linear grooves have an average length that is 30 to 65% of the radius of the polishing surface. Such linear grooves form an intersection with a spiral groove or a concentric groove in the polishing surface.

[0047] The distance from the center of the radial groove to the radius of the polished surface is 5% of the distance from the center of the radial groove to the radius of the polished surface. Similarly, the distance from the center of the radial groove to the radius of the polished surface is 10% of the distance from the center of the radial groove to the radius of the polished surface.

[0048] Referring to FIG. 1, in the polishing pad 10, the linear grooves S1 to S8 formed on the polishing surface have a first end E1 in a region of 5 to 10% of the radius of the polishing surface from the center G of the radial groove that coincides with the center of the spiral groove H. Also, they have a second end E2 in a region of 35 to 70% of the radius of the polishing surface from the center G of the radial groove that coincides with the center of the spiral groove H. And, the linear grooves S1 to S8 have an average length of 30 to 65% of the radius of the polishing surface. Also, referring to FIG. 2, in the polishing pad 20, the linear grooves S1 to S8 formed on the polishing surface have a first end E1 in a region of 5 to 10% of the radius of the polishing surface from the center G of the radial groove that coincides with the center of the concentric annular grooves C1 to C11. Also, they have a second end E2 in a region of 35 to 70% of the radius of the polishing surface from the center G of the radial groove that coincides with the center of the concentric groove. The linear grooves S1 to S8 have an average length that is 30 to 65% of the radius of the polishing surface.

[0049] That is, in the polishing pad 10 or 20 of this embodiment, the first end E1 of each of the eight linear grooves S1 to S8 is arranged along an imaginary circle K1 indicating a position at about 7% of the radius of the polishing surface from the center G of the radial groove, and the second end E2 is arranged along an imaginary circle K2 indicating a position at about 52.5% of the radius of the polishing surface from the center G of the radial groove. The eight linear grooves S1 to S8 have an average length that is about 45.5% of the radius of the polishing surface.

[0050] In this manner, by positioning the first end portion, which is the starting point of the linear groove, in an area that is 5 to 10% of the radius of the polishing surface from the center of the radial groove, the slurry dropped onto the polishing surface penetrates into the linear groove at an appropriate time, making it easier to distribute the slurry evenly over the polishing area.

[0051] When the first end is present in an area that is less than 5% of the radius of the polishing surface from the center of the radial groove, the slurry that has accumulated near the central area of ​​the polishing surface tends to preferentially enter the linear grooves rather than the spiral grooves or the concentric grooves, and the amount of slurry supplied near the central area becomes non-uniform, resulting in a decrease in the polishing rate. Also, when the first end, which is the starting point of the linear grooves, is present in an area that is more than 10% of the radius of the polishing surface from the center of the radial groove, the slurry that has accumulated near the central area tends to have difficulty entering the linear grooves, resulting in a decrease in the amount of slurry supplied to the polishing area.

[0052] On the other hand, the second end of the linear groove is formed to be present in a region that is 35 to 70% of the radius of the polishing surface from the center of the radial groove. By having the second end of the linear groove present in a region that is 35 to 70% of the radius of the polishing surface from the center of the radial groove, the slurry that has entered the linear groove from the vicinity of the central region is appropriately sent to the polishing region, while not being sent 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 peripheral region of the polishing surface, and a sufficient amount of slurry is easily retained in the polishing region. It is further preferable that the second end of the linear groove is located in a region that is 40 to 65% of the radius of the polishing surface from the center of the radial groove.

[0053] When the second end of the linear groove is located in an area that is less than 35% of the radius of the polishing surface from the center of the radial groove, the length of the linear groove becomes too short, making it difficult for the slurry that has infiltrated into the linear groove to reach the polishing area sufficiently, resulting in a shortage of slurry supply in the polishing area and a decrease in the polishing rate. When the second end of the linear groove is located in an area that is more than 70% of the radius of the polishing surface from the center of the radial groove, too much slurry is supplied near the peripheral area of ​​the polishing surface, causing the slurry to leak out of the system from the periphery and to be wasted. As a result, the distribution of the slurry in the polishing area becomes non-uniform, resulting in a decrease in the polishing rate.

[0054] The length ratio of the linear grooves constituting such radial grooves is 30 to 65% of the radius of the polishing surface, preferably 35 to 60% of the average length. If the average length ratio of the linear grooves is less than 30% of the radius of the polishing surface, the slurry that has infiltrated into the linear grooves does not reach the polishing area sufficiently, resulting in a shortage of slurry supply in the polishing area and a decrease in polishing speed. If the average length ratio of the linear grooves exceeds 65% of the radius of the polishing surface, the slurry is supplied too much near the peripheral area of ​​the polishing surface, so that the slurry leaks out of the system from the peripheral area and is easily wasted. The average length of the linear grooves is also the average of the lengths of the linear grooves.

[0055] The number of linear grooves constituting the radial groove is not particularly limited as long as it is 2 or more, but 4 to 24, and more preferably 5 to 16, are preferable because they have a good balance between the supplyability and dischargeability of slurry, and therefore improve the slurry retention in the polishing area.If the number of linear grooves is too small, the supply of slurry to the polishing area is likely to be insufficient, and if the number is too large, the dischargeability to the polishing surface increases, the amount of slurry that each groove supplies is insufficient, and the supplyability of slurry to the polishing area tends to be uneven.

[0056] The linear grooves may be straight or curved, but are preferably straight in that the amount of slurry supplied or discharged can be easily controlled.

[0057] The cross-sectional shape of the linear groove is not particularly limited. Specifically, the cross-sectional shape of the linear groove in the direction perpendicular to the longitudinal direction is not particularly limited, and may be a quadrangular shape such as a rectangle, a square, a trapezoid, or an inverted trapezoid, a triangular shape, a semicircular shape, a semi-elliptical shape, or the like. Among these, a quadrangular shape is preferred because it is excellent in processability, slurry retention, and supply stability.

[0058] In addition, the linear groove also preferably has a cross section inclined so that the groove is inversely tapered toward the opening in order to suppress the generation of burrs during polishing. Specifically, it is preferable that the groove has a so-called Y-shape having a tapered portion in which two corners forming a rectangular groove located on the polishing surface are chamfered so as to be inclined at a predetermined angle β, or that the cross section is an inverted trapezoid formed so that the oblique side is inclined at a predetermined angle β with respect to the two corners forming the base angle. The angle of such inclination is not particularly limited, but is preferably 20 degrees to less than 90 degrees, further 25 to 80 degrees, and particularly 30 to 75 degrees. In particular, when the angle is 30 to 80 degrees, the generation of burrs that tend to occur at the corners of the groove during polishing is easily suppressed, and thus the decrease in polishing speed and the decrease in polishing uniformity are easily suppressed.

[0059] 4, the width of the linear groove is preferably 0.1 to 10 mm, more preferably 0.2 to 5 mm, in terms of a good balance between the areas of the radial grooves and the land area, as the average width Wa (mm) of the linear grooves is the width of the linear grooves. The width of the linear groove is defined in the same manner as the width of the spiral groove or concentric groove described above, in the cross-sectional shape when cut in a direction perpendicular to the length direction.

[0060] In addition, the depth of the linear groove is preferably about 0.3 to 3.0 mm, or more preferably about 0.5 to 2.5 mm, as the average depth of the deepest part of the linear groove, in order to ensure sufficient supply of the slurry to the polishing area and to stabilize the polishing performance by suppressing the deformability of the polishing pad. If the linear groove is too deep, the volume of the linear groove is likely to be large, and it is necessary to drip more slurry into the polishing area in order to sufficiently spread the slurry to the polishing area during polishing, which may be undesirable in terms of cost. If the linear groove is too shallow, the volume of the linear groove is likely to be small, and the slurry overflows from the land area of ​​the central area during polishing, making it difficult for the slurry to reach the polishing area sufficiently. If the linear groove is too shallow, the linear groove becomes even shallower due to wear of the polishing surface when the polishing pad is used continuously, and the effect of increasing the polishing speed tends to be difficult to maintain.

[0061] The cross-sectional area of ​​the linear groove is the average cross-sectional area of ​​the cross section perpendicular to the length direction, as shown in FIG. 2 ), 0.3 to 4.5 mm 2 , and even 0.5 to 4.0 mm 2 It is preferable that the average cross-sectional area of ​​the linear groove is too large in order to ensure that the slurry is sufficiently distributed over the polishing area of ​​the polishing surface during polishing, which may be undesirable in terms of cost. Also, if the average cross-sectional area of ​​the linear groove is too small, the slurry tends to overflow the land area of ​​the central region before being distributed over the polishing area during polishing, which makes it difficult to sufficiently distribute the slurry over the polishing area of ​​the polishing surface. The average cross-sectional area of ​​the linear groove is also the average cross-sectional area of ​​each linear groove.

[0062] The depth, groove width Wa, and cross-sectional area Sa of the linear grooves are also based on an unused polishing pad before break-in processing.

[0063] In the polishing pad of this embodiment, an intersection between a linear groove and a spiral groove or a concentric groove exists within a region of 5 to 70% of the radius of the polishing surface from the center of the radial groove.

[0064] 1, on the polishing surface of the polishing layer 1 of the polishing pad 10, a spiral groove H with 10 turns is formed in an area of ​​4.5 to 100% radius of the polishing surface from the spiral center with a uniform groove pitch P. The spiral groove H with turns 1 to 6 intersects with the linear grooves S1 to S8 to form 41 intersections. These intersections exist within an area of ​​about 7 to 52.5% radius, surrounded by a virtual circle K1 indicating a position of about 7% radius of the polishing surface from the center of the spiral groove H, and a virtual circle K2 indicating a position of about 52.5% radius of the polishing surface from the center of the spiral groove H.

[0065] 2, concentric annular grooves C1-C11 are formed at a uniform groove pitch P on the polishing surface of the polishing layer 21 of the polishing pad 20 over an area of ​​at least 5-90% of the radius of the polishing surface from the center of the concentric circle. Each of the linear grooves S1-S8 intersects with the annular grooves C2-C6 to form 40 intersections. These intersections are located within an area of ​​about 7-52.5% of the radius of the polishing surface from the center, surrounded by a virtual circle K1 indicating a position at a distance of about 7% of the radius of the polishing surface from the center G of the concentric grooves and a virtual circle K2 indicating a position at a distance of about 52.5% of the radius of the polishing surface from the center of the spiral groove H.

[0066] In this way, by having the intersection of the linear groove and the spiral groove or the concentric groove in the region of 5-70% of the radius of the polishing surface from the center of the radial groove, the slurry that has entered the linear groove can be quickly supplied to the polishing region and easily retained. If the intersection is in a region of more than 70% of the radius of the polishing surface from the center of the radial groove, the slurry will spread too far to the peripheral region of the polishing surface during polishing, and the slurry will easily leak out of the system from the peripheral edge of the polishing surface, resulting in a decrease in the amount of slurry retained in the polishing region and a decrease in the polishing rate. In addition, if the intersection is in a region of less than 5% of the radius of the polishing surface from the center of the radial groove, the slurry dropped on the polishing surface will be dropped directly on the linear groove and will easily bounce back, which will easily cause variations in the supply speed within the polishing surface.

[0067] The polishing pad of this embodiment has a cross-sectional area Sa (mm 2 ) and the cross-sectional area Sb (mm 2 ) satisfies 0.1≦Sb / Sa<1.0, and preferably satisfies 0.15≦Sb / Sa≦0.85. Fig. 3A shows the cross-sectional area Sb of a spiral groove or a concentric groove in a direction perpendicular to the tangential direction, and Fig. 4 shows the cross-sectional area Sa of a line segment groove in a direction perpendicular to the length direction.

[0068] When the ratio Sb / Sa, which is the cross-sectional area Sb of the spiral groove or the concentric groove to the cross-sectional area Sa of the linear groove, is 1.0 or more, the slurry flows easily into the spiral groove or the concentric groove, so that the supply of the slurry to the polishing area is reduced, and the polishing speed is reduced.In addition, when Sb / Sa is less than 0.1, the slurry flows preferentially too much into the linear groove, so that the slurry overflows into the land area near the central area of ​​the polishing surface, and the supply of the slurry to the polishing area tends to be reduced.

[0069] Furthermore, it is preferable that Sb / Sa is 0.25≦Sb / Sa≦0.85, and further preferably 0.44≦Sb / Sa≦0.80, since a higher polishing rate can be obtained and excellent polishing uniformity can be obtained within the polished surface of the material to be polished.

[0070] In addition, in the polishing pad of this embodiment, the groove width Wa (mm), which is the average width of the linear groove, is larger than the groove width Wb (mm), which is the average width of the spiral groove or the concentric groove, specifically, 0.1≦Wb / Wa<1.0, further 0.1≦Wb / Wa≦0.9, and particularly 0.1≦Wb / Wa≦0.6, since the slurry flows quickly into the linear groove, and the supplyability to the polishing area tends to improve. If the ratio Wb / Wa of the groove width Wb to the groove width Wa is too high, the slurry tends to flow easily into the spiral or concentric groove, and the supplyability of the slurry to the polishing area tends to decrease. If Wb / Wa is too low, the slurry flows preferentially too much into the linear groove, and the slurry overflows into the land area near the central area of ​​the polishing surface, and the supplyability of the slurry to the polishing area tends to decrease.

[0071] In addition, in the polishing pad of this embodiment, the groove width Wb (mm), which is the average width of the spiral groove or the concentric groove, and the groove pitch P (mm) preferably satisfy 0.02≦Wb / P≦0.25, and further 0.025≦Wb / P≦0.16. If the average width of the spiral groove or the concentric groove is too large relative to the groove pitch P (mm), the polishing surface that contacts the polished material tends to become too small, decreasing the polishing efficiency, and if it is too small, the slurry supplied through the grooves tends to be insufficient on the polishing surface.

[0072] In addition, the polishing pad of this embodiment has a groove width Wa (mm) which is the average width of the linear grooves, a groove width Wb (mm) which is the average width of the spiral grooves or concentric grooves, and an average groove pitch P (mm) of the spiral grooves or concentric grooves, which are within the range of 0.20≦{Wb 2 / (P×Wa)}×100≦25, and further, 0.25≦{Wb 2 / (P×Wa)}×100≦15, especially 0.25≦{Wb2 It is preferable that {Wb / (P×Wa)}×100≦10 is satisfied. 2 When {Wb / (P×Wa)}×100 is too large, the slurry tends to flow preferentially into the spiral grooves or the concentric grooves, and the supply of the slurry to the polishing area is reduced. 2 If {P×Wa / (P×Wa)×100} is too small, the slurry will preferentially penetrate into the linear grooves, causing the slurry to overflow into the land area near the central region of the polishing surface, which tends to reduce the supply of slurry to the polishing region.

[0073] The material forming the polishing layer contained in the polishing pad of this embodiment is a synthetic or natural polymeric material that has been used in the manufacture of the polishing layer of a polishing pad in the past, and is not particularly limited. Specific examples of the polymeric material 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 may be used alone or in combination of two or more. Among these, it is particularly preferable to use polyurethane as the main component, since it provides a polishing layer that is excellent in planarization and is less susceptible to scratches. The polyurethane used as the material forming the polishing layer will be described in detail below as a representative example.

[0074] Polyurethane is obtained by reacting polyurethane raw materials including a polymeric diol, an organic diisocyanate, and a chain extender. Examples of the polyurethane raw materials, that is, the polymeric diol, the organic diisocyanate, and the chain extender, include the following compounds.

[0075] Specific examples of polymer diols include polyether diols such as polyethylene glycol and polytetramethylene glycol, polyester diols such as poly(nonamethylene adipate) diol, poly(2-methyl-1,8-octamethylene adipate) diol and poly(3-methyl-1,5-pentamethylene adipate) diol, and polycarbonate diols such as poly(hexamethylene carbonate) diol and poly(3-methyl-1,5-pentamethylene carbonate) diol, etc. These may be used alone or in combination of two or more.

[0076] Specific examples of organic diisocyanates include aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-bis(isocyanatomethyl)cyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 1,5-naphthylene diisocyanate. These may be used alone or in combination of two or more. Among these, 4,4'-diphenylmethane diisocyanate is preferred because the polishing layer obtained has excellent abrasion resistance.

[0077] The chain extender may be a low molecular weight compound having two or more active hydrogen atoms in the molecule that can react with an isocyanate group and a molecular weight of 350 or less. Specific examples of the chain extender include diols such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-bis(β-hydroxyethoxy)benzene, 1,9-nonanediol, cis-2-butene-1,4-diol, and spiroglycol; and diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, hydrazine, xylylenediamine, isophoronediamine, and piperazine. These may be used alone or in combination of two or more. Among these, it is particularly preferable to include at least one selected from 1,4-butanediol, cis-2-butene-1,4-diol, 1,5-pentanediol, and 1,9-nonanediol.

[0078] The mixing ratio of each component of the polyurethane raw material is appropriately adjusted in consideration of the properties to be imparted to the polishing layer, and for example, it is preferable to mix each component in such a ratio that the isocyanate group contained in the organic diisocyanate is 0.95 to 1.3 mol, more preferably 0.96 to 1.1 mol, and particularly preferably 0.97 to 1.05 mol, per mol of active hydrogen atom contained in the polymer diol and chain extender. If the isocyanate group contained in the organic diisocyanate is too small, the mechanical strength and abrasion resistance of the obtained polyurethane tend to decrease. In addition, if the isocyanate group contained in the organic diisocyanate is too large, the productivity of polyurethane and the storage stability of the polyurethane raw material tend to decrease.

[0079] The proportion of nitrogen atoms derived from the isocyanate groups of the organic polyisocyanate in the polyurethane is preferably 4.8 to 7.5 mass%, more preferably 5.0 to 7.3 mass%, and particularly preferably 5.2 to 7.1 mass%, in order to obtain a polishing layer that is particularly excellent in flattening properties and scratch resistance. If the proportion of nitrogen atoms derived from the isocyanate groups is too low, the hardness of the obtained polishing layer tends to be low.

[0080] In addition, the polyurethane used as the material for forming the polishing layer is preferably a thermoplastic polyurethane, since a polishing layer having high hardness and excellent flattening properties can be obtained. The term "thermoplastic" means a property that can be melted and molded by a heating process such as extrusion molding, injection molding, calendar molding, 3D printer molding, etc. Such a thermoplastic polyurethane is produced by using a polyurethane raw material containing a polymer diol, an organic diisocyanate, and a chain extender, and by using a known polyurethane production method such as a prepolymer method or a one-shot method. In particular, a method of melt-kneading and melt-polymerizing a polyurethane raw material in the substantial absence of a solvent, and further a method of continuously melt-polymerizing using a multi-screw type extruder are preferable in terms of excellent productivity.

[0081] In addition, the polishing layer is preferably of a non-foamed structure (non-porous). A polishing layer of a non-foamed structure is preferable because it can maintain high hardness and exhibits better flattening properties. In addition, a polishing layer of a non-foamed structure is preferable because pores are not exposed on its surface, and the abrasive grains in the slurry do not aggregate or adhere in the pores, so scratches are unlikely to occur. In addition, a polishing layer of a non-foamed structure is preferable because the wear rate of the polishing layer is lower than that of a polishing layer of a foamed structure, so the life span is longer.

[0082] The method of manufacturing the polishing layer is not particularly limited, but for example, the polymeric material composition for the polishing layer, which is prepared by blending the above-mentioned polymeric material forming the polishing layer with additives for the polishing layer that have been conventionally used, as necessary, is formed into a sheet using a known sheeting method. Specifically, for example, the polymeric material composition for the polishing layer is melt-extruded by an extruder such as a single-screw extruder or a twin-screw extruder equipped with a T-die to form a sheet. The sheet may also be produced by molding the above-mentioned material composition for the polishing layer into a block shape and slicing the block-shaped molded body. 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, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and especially preferably 99% by mass or more of the polymeric material. 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.

[0083] The obtained sheet is adjusted to a desired thickness by grinding or the like, and formed into a circular shape by cutting, punching, cutting, etc., to obtain a sheet for a polishing layer. The polishing layer used in the polishing pad of this embodiment is obtained by forming one surface of the circular sheet for a polishing layer as a polishing surface, and providing radial grooves including at least two linear grooves extending from the central region to the peripheral region of the polishing surface, as described above, and a spiral groove or a concentric groove formed from the central region to the peripheral region.

[0084] For example, in the case of a polishing layer containing thermoplastic polyurethane having a non-foamed structure, the density of the polishing layer is 1.0 g / cm 3 More than 1.1g / cm 3 Above, especially 1.2g / cm 3 If the density of the polishing layer containing the thermoplastic polyurethane with a non-foamed structure is too low, the polishing layer becomes too soft, and the polishing rate and polishing uniformity tend to decrease.

[0085] In addition, the D hardness of the polishing layer is preferably 45 to 90, more preferably 50 to 88, particularly preferably 55 to 87, and even more preferably 60 to 86, since this provides excellent polishing uniformity due to high planarization and is also effective in suppressing the occurrence of scratches on the surface of the material to be polished.

[0086] The method of forming the radial grooves, spiral grooves, or concentric grooves on the polishing surface is not particularly limited. Specifically, for example, a method of forming each groove by cutting one side of the sheet for polishing layer; a method of forming grooves by melting or volatilizing a polymer by stamping and contacting a heated mold or metal wire on one side of the sheet for polishing layer; a method of forming grooves by decomposing or volatilizing a polymer by laser processing one side of the sheet for polishing layer; a method of molding a sheet for polishing layer with a polishing surface having grooves using a mold in which a convex portion for forming grooves is previously formed; etc. are included. Among these, the cutting method or the transfer processing method is preferred from the viewpoint of excellent productivity, and the cutting method is particularly preferred from the viewpoint of excellent processing accuracy. The thickness of the polishing layer is preferably about 0.4 to 5.0 mm, more preferably about 0.6 to 4.5 mm.

[0087] As described above, the polishing layer included in the polishing pad is manufactured. The polishing pad of the present embodiment may be used as a single-layer polishing pad with the polishing layer manufactured in this way, or may be used as a polishing pad having a laminated structure of two or more layers by laminating other layers such as a cushion layer or a support layer on the opposite side of the polishing surface of the polishing layer.

[0088] Fig. 5 is a partial schematic side view of the polishing pad 10 and the polishing pad 20. Referring to Fig. 5, in the polishing pad 10 and the polishing pad 20, a cushion layer 7 is laminated via an adhesive layer 6 on the counter-polishing surface, which is the surface opposite to the polishing surface F of the polishing layer 1 or the polishing layer 11. A laminated structure in which cushion layers are laminated is particularly preferable because it is easy to improve polishing uniformity over the entire surface. When the polishing pad has a laminated structure, a cushion layer or a support layer is laminated via an adhesive or a bonding agent on the surface opposite to the polishing surface of the polishing layer.

[0089] The C hardness of the cushion layer is preferably 20 to 70. The material of the cushion layer is not particularly limited, but examples thereof include a sheet made of nonwoven fabric impregnated with resin, and a sheet of elastomer having a non-foamed structure or a foamed structure. Specific examples include composites made of nonwoven fabric impregnated with polyurethane; rubbers such as natural rubber, nitrile rubber, polybutadiene rubber, and silicone rubber; thermoplastic elastomers such as polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and fluorine-based thermoplastic elastomers; foamed plastics; and sheets of polyurethane. Among these, a sheet of polyurethane having a foamed structure is particularly preferred because it is easy to obtain a desired flexibility.

[0090] The polishing pad of this embodiment described above is preferably used for CMP. Next, an embodiment of CMP using the polishing pad 10 of this embodiment will be described.

[0091] In CMP, for example, a CMP apparatus 100 including a circular rotating platen 101, a slurry supply nozzle 102, a carrier 103, and a pad conditioner 104 as shown in Fig. 6 is used. A polishing pad 10 is attached to the surface of the rotating platen 101 by a double-sided adhesive sheet or the like. In addition, the carrier 103 supports a workpiece 50 to be polished.

[0092] In the CMP apparatus 100, the rotating platen 101 is rotated, for example, in the direction indicated by the arrow, by a motor (not shown). The carrier 103 is rotated, for example, in the direction indicated by the arrow, by a motor (not shown) while pressing the surface to be polished of the workpiece 50 against the polishing surface of the polishing pad 10. The pad conditioner 104 is rotated, for example, in the direction indicated by the arrow. When the diameter of the pad conditioner 104 is smaller than the diameter of the workpiece 50, the pad conditioner 104 is oscillated in the radial direction of the rotating platen 101 in order to make the entire area of ​​the polishing pad in contact with the workpiece roughness suitable for polishing.

[0093] When an unused polishing pad is used, a conditioning called break-in is usually performed before polishing a workpiece, in order to finely roughen the polishing surface of the polishing pad to form a roughness suitable for polishing. Specifically, the surface of the polishing pad 10, which is fixed to a rotating platen 101 and rotated, is conditioned by pressing a pad conditioner 104 for CMP against the surface of the polishing pad 10 while running water over the surface. As the pad conditioner, for example, a pad conditioner in which diamond particles are fixed to the carrier surface by nickel electrodeposition or the like is used.

[0094] After the break-in is completed, the polishing of the surface of the workpiece is started. In the polishing, a slurry is supplied from a slurry supply nozzle to the surface of the rotating polishing pad. The slurry contains, for example, a liquid medium such as water or oil; an abrasive such as silica, alumina, cerium oxide, zirconium oxide, silicon carbide; a base, an acid, a surfactant, an oxidizing agent, a reducing agent, a chelating agent, etc. In addition, when performing CMP, a lubricating oil, a coolant, etc. may be used together with the slurry as necessary. Then, the workpiece fixed to the carrier and rotating is pressed against the polishing pad with the slurry evenly spread over the polishing surface. Then, the polishing process is continued until a predetermined flatness and polishing amount are obtained. The finishing quality is affected by adjusting the pressing force applied during polishing and the speed of the relative movement between the rotating platen and the carrier.

[0095] The polishing conditions are not particularly limited, but in order to perform polishing efficiently, the rotation speed of each of the platen and the workpiece is preferably low, 300 rpm or less, and the pressure applied to the workpiece to press it against the polishing pad is preferably 150 kPa or less from the viewpoint of preventing scratches after polishing. In addition, during polishing, it is preferable to continuously or discontinuously supply slurry to the polishing pad so that the slurry is evenly distributed over the polishing surface.

[0096] After polishing, the workpiece is thoroughly washed and then dried using a spin dryer or the like to remove any water droplets adhering to the workpiece, resulting in a smooth polished surface.

[0097] The CMP of this embodiment is preferably used for polishing in the manufacturing process of various semiconductor devices, MEMS (Micro Electro Mechanical 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 predetermined wiring, and wiring materials such as copper, aluminum, and tungsten; glass, quartz, optical substrates, and hard disks. The polishing pad of this embodiment is particularly preferably used for polishing insulating films and wiring materials formed on semiconductor substrates. EXAMPLES

[0098] The present invention will be described in more detail below with reference to examples, although the scope of the present invention is not limited to these examples in any way.

[0099] [Production Example 1] Polytetramethylene glycol having a number average molecular weight of 850 [abbreviation: PTMG], polyethylene glycol having a number average molecular weight of 600 [abbreviation: PEG], 1,4-butanediol [abbreviation: BD], and 4,4'-diphenylmethane diisocyanate [abbreviation: MDI] were blended in such a ratio that the mass ratio of PTMG:PEG:BD:MDI was 24.6:11.6:13.8:50.0, and the mixture was continuously fed to a twin-screw extruder rotating coaxially by a metering pump to continuously melt-polymerize thermoplastic polyurethane. The polymerized thermoplastic polyurethane melt was then continuously extruded into water in the form of a strand, and then chopped into pellets by a pelletizer. The pellets were dehumidified and dried at 70°C for 20 hours, and then fed to a single-screw extruder and extruded from a T-die to form a sheet. The surface of the obtained sheet was ground to obtain a uniform sheet with a thickness of 2.0 mm, and then cut into a circular shape with a diameter of 740 mm to obtain a non-foamed sheet for abrasive layer. The D hardness of the sheet for abrasive layer measured at a measurement temperature of 25°C according to JIS K 7311 was 62.

[0100] [Production Example 2] In Production Example 1, instead of using the polyurethane raw material blended in such a ratio that the mass ratio of PTMG:PEG:BD:MDI was 24.6:11.6:13.8:50.0, a polyurethane raw material blended in such a ratio that the mass ratio of PTMG:MPD:BD:MDI was 12.5:5.7:17.5:64.3 was used, polytetramethylene glycol having a number average molecular weight of 850, 3-methyl-1,5-pentanediol [abbreviation: MPD], 1,4-butanediol, and 4,4'-diphenylmethane diisocyanate was 850. Then, a sheet for polishing layer, which is a non-foamed body, was obtained in the same manner as in Production Example 1. The D hardness of the sheet for polishing layer measured at a measurement temperature of 25°C according to JIS K 7311 was 86.

[0101] [Production Example 3] In Production Example 1, instead of using the polyurethane raw material blended in such a ratio that the mass ratio of PTMG:PEG:BD:MDI was 24.6:11.6:13.8:50.0, a polyurethane raw material blended in such a ratio that the mass ratio of PTMG:PEG:ND:MDI was 32.2:5.7:19.6:42.5 was used, in which polytetramethylene glycol having a number average molecular weight of 850, polyethylene glycol having a number average molecular weight of 600 [abbreviation: PEG], 1,9-nonanediol [abbreviation: ND], and 4,4'-diphenylmethane diisocyanate were blended, in which the mass ratio of PTMG:PEG:ND:MDI was 32.2:5.7:19.6:42.5, was used. Thermoplastic polyurethane pellets were obtained in the same manner as in Production Example 1. Then, a sheet for polishing layer, which is a non-foamed body, was obtained in the same manner as in Production Example 1. The D hardness of the sheet for polishing layer measured at a measurement temperature of 25°C according to JIS K 7311 was 56.

[0102] [Production Example 4] In Production Example 1, instead of using the polyurethane raw material blended in such a ratio that the mass ratio of PTMG:PEG:BD:MDI was 24.6:11.6:13.8:50.0, a polyurethane raw material blended in such a ratio that the mass ratio of PTMG:PEG:MPD:ND:MDI was 36.1:6.4:1.3:15.7:40.5 was used, and thermoplastic polyurethane pellets were obtained in the same manner as in Production Example 1. Then, a sheet for abrasive layer, which is a non-foamed body, was obtained in the same manner as in Production Example 1. The D hardness of the sheet for abrasive layer measured at a measurement temperature of 25°C according to JIS K 7311 was 46.

[0103] [Examples 1 to 25 and Comparative Examples 1 to 13] On one polishing surface of the sheet for polishing layer having a D hardness of 62 obtained in Production Example 1, grooves having the patterns shown in Tables 1 and 2 were formed by cutting.

[0104] In Example 12 and Comparative Example 4, concentric grooves were formed with the center of the concentric circle offset by 15 mm from the center of the polished surface. In this case, the center of the concentric groove was located at a distance of about 4% of the radius from the center of the polished surface. In Example 13, the center of the radial groove coincided with the center of the concentric groove.

[0105] In addition, the linear grooves forming the concentric grooves, spiral grooves, lattice grooves, and radial grooves in each embodiment were chamfered as necessary so that the slope of the groove was inclined at an angle in the range of 35 to 80 degrees. The slope of the inverted trapezoid groove was also formed so as to be inclined at an angle in the range of 35 to 80 degrees. The cross-sectional area changes as the angle of the slope changes.

[0106] The groove width and cross-sectional area of ​​each of the linear grooves forming the concentric grooves, spiral grooves, lattice grooves, and radial grooves were measured based on a scanning electron microscope (SEM) image at 200 times the cross section. Specifically, the cut surface of the grooves of each polishing layer was photographed evenly at 18 points, the groove width of each image was measured, and the cross-sectional area was measured by image processing, and the average value was calculated. In addition, the average groove pitch P of the concentric grooves, spiral grooves, and lattice grooves was measured at 8 points evenly selected from the area of ​​the polishing surface that contacts the silicon wafer using a scale loupe, and the average was taken as the average groove pitch P. In addition, the depth of each groove was measured at 8 points evenly selected from the area that contacts the silicon wafer using a depth gauge "E-DP2J" manufactured by Nakamura Seisakusho Co., Ltd., and the measured values ​​were averaged.

[0107] A cushion layer was attached to the back side of the polishing layer with a double-sided adhesive sheet to prepare a multi-layer polishing pad. The cushion layer was made of a 0.8 mm thick polyurethane foam sheet, "Poron H48" manufactured by Inoac Corporation. The polishing properties of the obtained polishing pad were evaluated by the following evaluation method. <Polishing speed> The obtained polishing pad was attached to a polishing device "FREX-300" manufactured by Ebara Corporation. A slurry was prepared by diluting "HS-8005" manufactured by Hitachi Chemical Co., Ltd. by 10 times to prepare a slurry, and a 12-inch diameter silicon wafer having a silicon oxide film on its surface with a thickness of 2000 nm was polished for 60 seconds while supplying the slurry to the polishing surface of the polishing pad at a rate of 200 mL / min under the conditions of a platen rotation speed of 100 rpm, a head rotation speed of 99 rpm, and a polishing pressure of 30.0 kPa.

[0108] Then, using a pad conditioner (A.L.M.T.'s diamond dresser (diamond grit #100 blocky, base metal diameter 19 cm)), the surface of the polishing pad was conditioned for 30 seconds while running pure water at a rate of 150 mL / min under the conditions of a dresser rotation speed of 70 rpm, a polishing pad rotation speed of 100 rpm, and a dresser load of 20 N. Then, another silicon wafer was polished again, and conditioning was performed for another 30 seconds. Then, after polishing for 60 seconds, conditioning of the polishing pad was performed for 30 seconds. Then, another silicon wafer was polished again, and conditioning was performed for another 30 seconds. In this manner, 10 silicon wafers were polished.

[0109] The thickness of the silicon oxide film on the 10th polished silicon wafer was measured at 49 points on the wafer before and after polishing, and the polishing rate (nm / min) at each point was calculated. Specifically, the average of the polishing rates at the 49 points was defined as the polishing rate.

[0110] The improvement rate of the polishing rate for each Example was calculated by the following formula, based on the polishing rate of 1050 nm / min that was achievable with a conventional general groove shape. Improvement rate of polishing speed (%) = polishing speed ÷ 1050 × 100

[0111] The results are shown in Tables 1 and 2 below.

[0112] [Table 1]

[0113]

Table 2

[0114] The polishing pads obtained in Examples 1 to 25 according to the present invention shown in Table 1 all had a high polishing rate. On the other hand, the polishing pads obtained in Comparative Examples 1 to 13 shown in Table 2 all had a low polishing rate. Further, referring to Table 1, the polishing pads obtained in Examples 1 to 21 that satisfy 0.25 ≦ Sb / Sa ≦ 0.85 and 0.2 ≦ {Wb 2 / (P × Wa)} × 100 ≦ 21.0 had particularly high polishing rates.

[0115] <Effect of Sb / Sa on polishing uniformity> Twelve polishing pads of examples with different Sb / Sa were selected. Then, in the same manner as the measurement method of 〈polishing rate〉, a plurality of silicon wafers were polished. And the polishing uniformity of the polishing pad polished until the groove depth of the annular groove of the unused polishing layer decreased by 50% was evaluated as follows.

[0116] When the groove depth of the annular groove of the polishing layer decreased by 50%, the film thicknesses of the silicon oxide films before and after polishing of the silicon wafers were measured at 49 points within the wafer surface (excluding 3 mm at the edge), and the polishing rate (nm / min) at each point was obtained. Then, the average value and the standard deviation 1σ of the polishing rates at 49 points were calculated, and the coefficient of variation (unit: %) was obtained from the average value and the 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.

[0117]

Table 3

[0118] Referring to Table 3, Examples 4, 2, 10, 16, and 3 that satisfy 0.44 ≦ Sb / Sa ≦ 0.80 have a coefficient of variation of polishing uniformity 3.3%It is clear that the polishing uniformity is particularly excellent and the polishing rate is also high.

[0119] [Examples 26 to 28] Except for using the polishing layer sheet having a D hardness of 86 obtained in Production Example 2, the polishing layer sheet having a D hardness of 56 obtained in Production Example 3, or the polishing layer sheet having a D hardness of 49 obtained in Production Example 4, polishing pads were prepared in the same manner as in Example 10 (Examples 26, 27, and 28). Then, the effect of the D hardness of the polishing layer on the polishing uniformity was examined. Table 3 shows the evaluation results of the effect of the D hardness of the polishing layer on the polishing uniformity.

[0120] [Table 4]

[0121] Referring to Table 4, it can be seen that the polishing pads using the polishing layers of Examples 10 or 26 and 27, which have a JIS D hardness in the range of 56 to 86, have a significantly lower coefficient of variation in polishing uniformity and are particularly excellent in polishing uniformity compared to the polishing layer of Example 28, which has a JIS D hardness of 46.

[0122] [Examples 29 to 39 and Comparative Examples 14 to 24] On the polishing surface, which is one surface of the sheet for polishing layer obtained in Production Example 1, grooves having a pattern shown in Tables 5 and 6 were formed by cutting. In Examples 30 and 32, concentric grooves were formed with the center of the concentric circle being 15 mm off center from the center of the polishing surface. At this time, the center of the concentric groove was located at a distance of about 4% of the radius from the center of the polishing surface. In addition, the center of the radial groove coincided with the center of the concentric groove. In each Example, the groove was Y-shaped, inverted trapezoidal, or rectangular with the corners of the rectangular cross section chamfered. Then, the groove width, cross-sectional area, groove pitch, and depth of each groove were measured in the same manner as described above.

[0123] A cushion layer was attached to the back side of the polishing layer with a double-sided adhesive sheet to prepare a multi-layer polishing pad. The cushion layer was made of a 0.8 mm thick polyurethane foam sheet, "Poron H48" manufactured by Inoac Corporation. The polishing properties of the obtained polishing pad were evaluated by the following evaluation method.

[0124] <Polishing speed> The obtained polishing pad was attached to a polishing machine "FREX-300" manufactured by Ebara Corporation. A slurry was prepared by diluting "SEMI-SPERSE25" manufactured by Cabot Microelectronics by a factor of two to prepare a slurry, and a 12-inch diameter silicon wafer having a silicon oxide film on its surface with a thickness of 2000 nm was polished for 60 seconds while supplying the slurry to the polishing surface of the polishing pad at a rate of 200 mL / min under the conditions of a platen rotation speed of 100 rpm, a head rotation speed of 99 rpm, and a polishing pressure of 20.0 kPa.

[0125] Then, using a pad conditioner (A.L.M.T.'s diamond dresser (diamond grit #100 blocky, base metal diameter 19 cm)), the surface of the polishing pad was conditioned for 30 seconds while running pure water at a rate of 150 mL / min under the conditions of a dresser rotation speed of 70 rpm, a polishing pad rotation speed of 100 rpm, and a dresser load of 20 N. Then, another silicon wafer was polished again, and conditioning was performed for another 30 seconds. Then, after polishing for 60 seconds, conditioning of the polishing pad was performed for 30 seconds. Then, another silicon wafer was polished again, and conditioning was performed for another 30 seconds. In this manner, 10 silicon wafers were polished.

[0126] The thickness of the silicon oxide film on the 10th polished silicon wafer was measured at 49 points on the wafer before and after polishing, and the polishing rate (Å / min) at each point was calculated. Specifically, the average of the polishing rates at the 49 points was used as the polishing rate.

[0127] In addition, the improvement rate of the polishing rate in each Example was calculated by the following formula, based on the polishing rate of 2400 Å / min that was achievable with a conventional general groove shape. Improvement rate of polishing speed (%) = polishing speed ÷ 2400 × 100 The results are shown in Tables 5 and 6.

[0128] [Table 5]

[0129] [Table 6]

[0130] The polishing pads obtained in Examples 29 to 39 according to the present invention shown in Table 5 all had high removal rates. On the other hand, the polishing pads obtained in Comparative Examples 14 to 24 shown in Table 6 all had low removal rates. With reference to Table 5, the polishing pads satisfy 0.1≦Wb / Wa<1.0 and 0.2≦{Wb 2 The polishing pads obtained in Examples 28 to 37, which satisfied the condition {P×Wa}×100≦10, had a particularly high removal rate. [Explanation of symbols]

[0131] 1,11 Polishing layer 10,20 Polishing pad E1 First end E2 Second end C1~ C11 Annular groove (concentric groove) S1~S8 Linear grooves (radial grooves) H spiral groove F Polished surface

Claims

1. 1. A polishing pad comprising a polishing layer having a circular polishing surface, the polishing surface has a central region that is in the range of 0 to 10% of the radius from the center of the polishing surface, and a peripheral region that is in the range of 90 to 100% of the radius, The polishing layer is The present invention provides a method for manufacturing a vehicle having a vehicle body having a plurality of concentric circular grooves arranged from the central region to the peripheral region, the method comprising: providing at least one spiral groove or a plurality of concentric circular grooves arranged from the central region to the peripheral region; and providing at least two radial grooves extending from the central region to the peripheral region. a center of the spiral groove, a center of the concentric groove, and a center of the radial groove are present in the central region; the linear groove has an average length that is 30 to 65% of the radius of the polishing surface, and has a first end in a region that is 5 to 10% of the radius of the polishing surface from the center of the radial groove, and a second end in a region that is 35 to 70% of the radius of the polishing surface; The average cross-sectional area Sa (mm 2 ) and a cross-sectional area Sb (mm 2 ) satisfies 0.1≦Sb / Sa<1.

0.

2. 2. The polishing pad according to claim 1, wherein 0.25≦Sb / Sa≦0.85 is satisfied.

3. 2. The polishing pad according to claim 1, wherein 0.44≦Sb / Sa≦0.80 is satisfied.

4. The polishing pad according to any one of claims 1 to 3, wherein a groove width Wa (mm) which is an average width of the linear grooves and a groove width Wb (mm) which is an average width of the spiral grooves or the concentric grooves satisfy 0.1≦Wb / Wa<1.

0.

5. The polishing pad according to any one of claims 1 to 3, wherein a groove width Wb (mm) which is an average of the widths of the spiral grooves or the concentric grooves, and an average groove pitch P (mm) of the spiral grooves or the concentric grooves satisfy 0.02≦Wb / P≦0.

25.

6. A groove width Wa (mm) which is an average width of the linear grooves, a groove width Wb (mm) which is an average width of the spiral grooves or the concentric grooves, and an average groove pitch P (mm) of the spiral grooves or the concentric grooves are within the range of 0.2≦{Wb 2 4. The polishing pad according to claim 1, wherein the polishing pad satisfies the relationship: P×Wa×100≦25.

7. 4. The polishing pad according to claim 1, comprising the spiral groove.

8. 4. The polishing pad according to claim 1, comprising said concentric grooves.

9. 4. The polishing pad according to claim 1, wherein the polishing layer comprises a thermoplastic polyurethane.

10. 4. The polishing pad according to claim 1, wherein the polishing layer is a non-foamed material.

11. 4. The polishing pad according to claim 1, wherein the polishing layer has a JIS D hardness of 45 to 90.

12. The polishing layer has a density of 1.00 to 1.20 g / cm 3 4. The polishing pad according to claim 1, wherein

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