Polishing platen and method of manufacturing the polishing platen

Abstract

Embodiments of the present disclosure generally relate to a method for manufacturing a polishing platen for use in a chemical mechanical polishing (CMP) system, and a polishing platen formed therefrom. The method for manufacturing a polishing platen includes placing a polishing platen on a support of the manufacturing system. The manufacturing system includes the support and a cutting tool opposing the support. Here, the polishing platen includes a cylindrical metal body having a polymer layer disposed thereon, the polymer layer having a thickness of about 100 μm or greater. The method further includes removing at least a portion of the polymer layer using the cutting tool to form a polishing pad mounting surface. Advantageously, the method can be used to form a pad mounting surface having a desired flatness or shape, such as a concave or convex shape.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION

[0001] Embodiments described herein relate generally to polishing platens used in chemical mechanical polishing (CMP) systems and related methods of manufacturing polishing platens. [Background technology]

[0002] Chemical-mechanical polishing (CMP) is commonly used in the manufacture of high-density integrated circuits to planarize or polish layers of material deposited on a substrate. In a typical CMP process, a substrate is held in a carrier head. The carrier head presses the backside of the substrate against a rotating polishing pad in the presence of a polishing slurry. Material is removed across the surface of the material layer of the substrate in contact with the polishing pad by a combination of chemical and mechanical forces, provided by the polishing slurry and the relative motion between the substrate and the polishing pad.

[0003] Typically, a polishing pad is placed on a disk-shaped polishing platen having a surface. The surface is formed to have a desired flatness. The polishing pad is fixed to the surface of the platen using a pressure-sensitive adhesive layer interposed therebetween. Polishing pads generally have a limited useful life. Therefore, to prevent deterioration of CMP substrate processing results, polishing pads must be replaced periodically. Replacing a polishing pad generally involves manually pulling the polishing pad from the surface of the polishing platen with enough force to overcome the tensile strength of the adhesive interposed therebetween. The typical force required to remove a used polishing pad from the surface of the polishing platen is substantial. This force may lead to personal injury, damage to the polishing system, including damage to the polishing platen, or both.

[0004] Treating the surface of a polishing platen, such as by applying a coating of a low-adhesion material, e.g., a "non-stick" polymer coating, to the polishing platen can desirably reduce the force required to remove a used polishing pad therefrom. The treated surface can also desirably prevent corrosion of the polishing platen due to exposure to CMP polishing chemicals during normal processing. Unfortunately, the relatively high temperature processes that can be used to apply the low-adhesion material can undesirably deform, e.g., warp, a disk-shaped polishing platen, thereby reducing its surface flatness. Furthermore, the thickness of a typical conventional polymer coating is large enough to significantly deform under compressive loads applied to the polishing pad and polishing platen by the substrate and parts of the polishing head (e.g., the substrate holder) during the CMP process. The amount of local and global deformation of the polishing platen is generally inconsistent from one coated platen to another, contributing to inconsistent substrate polishing results between polishing platens in a multi-platen polishing system and / or between polishing platens in a single-platen and a multi-platen polishing system.

[0005]

[0005] Therefore, there is a need in the art for a method of manufacturing a polishing platen, and polishing platens formed therefrom, that addresses the above-mentioned problems. Summary of the Invention

[0006]

[0006] Embodiments of the present disclosure generally relate to methods of manufacturing polishing platens for use in chemical mechanical polishing (CMP) systems, polishing platens formed therefrom, and polishing methods using the polishing platens.

[0007] In one embodiment, a method for manufacturing a polishing platen is provided. The method includes placing a polishing platen on a support of a manufacturing system. The manufacturing system includes the support and a cutting tool opposing the support. The polishing platen includes a cylindrical metal body having a polymer layer disposed thereon, the polymer layer having a thickness of about 100 μm or greater. The method further includes removing at least a portion of the polymer layer using the cutting tool to form a polishing pad mounting surface. Advantageously, the method can be used to form a pad mounting surface having a desired flatness or shape (e.g., a concave or convex shape).

[0008] In another embodiment, a polishing platen is provided. The polishing platen includes a cylindrical metal body and a polymer coating layer disposed on the metal body to form a circular pad mounting surface. The pad mounting surface has a first surface height at a first radius and a second surface height at a second radius. The second radius is disposed radially inward of the first radius. The first and second surface heights are measured as distances from a reference plane parallel to the pad mounting surface at the first radius. The difference between the first surface height and the second surface height is about 25 μm or greater. In some embodiments, the first and second surface heights are averaged from multiple distance measurements taken at corresponding multiple equidistant positions along each radius.

[0009] In another embodiment, a polishing platen includes a cylindrical metal body and a polymer coating layer disposed on the metal body to form a circular pad mounting surface, the thickness of the polymer coating layer varying from a first radius of the pad mounting surface to a second radius disposed radially inward from the first radius. In some embodiments, the thickness at the second radius is averaged from multiple thickness measurements taken at corresponding multiple equidistant locations along the second radius, and the difference between the thickness at the first radius and the thickness at the second radius is about 25 μm or greater.

[0010]

[0010] In another embodiment, a method for polishing a substrate is provided. The method includes pressing a substrate against a surface of a polishing pad in the presence of a polishing fluid, wherein the polishing pad is disposed on a pad mounting surface of a polishing platen. The polishing platen includes a cylindrical metal body and a coating layer disposed on the surface of the metal body to form the polishing pad mounting surface. The average thickness of the coating layer across the pad mounting surface is less than about 250 μm, and the variation in thickness of the coating layer across the diameter of the pad mounting surface varies by about 25 μm or more. The pad mounting surface may have a flatness of about 25 μm or less and may have a concave or convex shape.

[0011]

[0011] In order that the above-mentioned features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly summarized above can be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure, and therefore should not be considered as limiting the scope of the present disclosure, since the present disclosure may admit of other equally effective embodiments. [Brief explanation of the drawings]

[0012] [Figure 1A]

[0012] A schematic side view of an exemplary polishing system according to one embodiment configured to use a polishing platen formed according to the methods described herein. [Figure 1B]

[0013] 1B is a schematic cross-sectional view of the platen assembly of FIG. 1A, according to one embodiment. [Figure 1C]

[0014] FIG. 1C is an enlarged view of a portion of FIG. 1B. [Figure 2]

[0015] 1A-1C illustrate a method for manufacturing a polishing platen according to one embodiment. [Figure 3]

[0016] 3 is a schematic side view of a manufacturing system that can be used to implement the method described in FIG. 2, according to one embodiment. [Figure 4]

[0017] 1 is a graph depicting the surface profile of a portion of a polishing platen formed in accordance with embodiments described herein. [Figure 5A]

[0018] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5B] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5C] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5D] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5E] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5F] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5G] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 5H] 1A-1C are schematic cross-sectional views illustrating various polishing platen surface profiles that may be formed in accordance with embodiments described herein. [Figure 6]

[0019] 1A-1C illustrate a method of polishing a substrate using a polishing platen formed in accordance with embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0013]

[0020] For ease of understanding, wherever possible, the same reference numerals have been used to designate identical elements common to the figures, and it is believed that elements disclosed in one embodiment can be beneficially utilized in other embodiments without specific mention.

[0014]

[0021]

[0002] Embodiments of the present disclosure generally relate to methods of manufacturing polishing platens for use in chemical mechanical polishing (CMP) systems, and polishing platens formed therefrom. Polishing platens formed according to embodiments herein generally include a structural component, such as a cylindrical platen body formed of metal, and a low-adhesion material layer disposed on the surface of the platen body to provide a polishing pad mounting surface. The low-adhesion material layer desirably reduces the amount of force required to remove the polishing pad from the polishing pad mounting surface after the polishing pad has reached the end of its useful life, and also protects the metal of the platen body from corrosion caused by polishing fluids.

[0015]

[0022] In many cases, the processes required to form and bond the low-adhesion material to the surface of the platen body require heating and maintaining the platen body at temperatures exceeding 300°C, e.g., 350°C or higher, during the material deposition process. Typically, the high-temperature processes used to form the low-adhesion material layer deform the cylindrical platen body, undesirably reducing the flatness of its pad mounting surface. For example, in some embodiments, the pad mounting surface of the platen body is machined to have a flatness deviation from a least-squares datum of about 25 μm or less before the low-adhesion material layer is formed thereon. After a coating layer is formed on the platen body, the pad mounting surface may lack flatness. For example, the pad mounting surface may have a deviation from a datum of about 25 μm or more, e.g., between about 25 μm and about 150 μm, even when the low-adhesion material coating layer has a thickness uniformity standard deviation of about 3 μm or less.

[0016]

[0023] Generally, distortion of the polishing platen's shape after a low-adhesion material coating process is unpredictable. Therefore, the low-adhesion material coating process can result in different surface profiles in different polishing platens formed using the same material coating process. For example, two different disk-shaped polishing platens formed using the same generally low-adhesion material coating process can each have different resulting surface shapes, including different hyperbolic paraboloid shapes or different randomly undulating surface shapes, with varying degrees of deviation from their least-squares reference planes. Unfortunately, variations in the surface shapes of different polishing platens formed using the same surface coating method can undesirably result in non-uniform substrate processing results from polishing platen to polishing platen within a multi-platen CMP system and / or across multiple single-platen or multi-platen CMP systems. Accordingly, embodiments herein provide a method for controlling the flatness and / or surface shape of a polishing platen during its manufacture, and a polishing platen formed using the method. In one embodiment, a method includes forming a relatively thick, low-adhesion layer of material on a disk-shaped platen body and then removing portions of the material layer therefrom to provide a polishing platen having a desired surface flatness and / or surface shape.

[0017]

[0024] Figure 1A is a schematic side view of an exemplary polishing system 100 including a platen assembly 102 formed using the methods described herein. Figure 1B is a schematic cross-sectional view of the platen assembly 102 of Figure 1A, where the platen assembly 102 includes a lower platen 104 and a polishing platen 106 disposed on and coupled to the lower platen 102. Figure 1C is an enlarged view of a portion of the polishing platen 106 shown in Figure 1B.

[0018]

[0025] The exemplary polishing system 100 includes a platen assembly 102 having a polishing pad 110 mounted thereon and a substrate carrier 108 positioned above the polishing pad 110, facing the polishing pad 110. The platen assembly 102 is rotatable about axis A, and the substrate carrier 108 is rotatable about axis B and configured to sweep back and forth from the inner diameter to the outer diameter of the platen assembly, in part to reduce uneven wear on the surface of the polishing pad 110. The polishing system 100 further includes a fluid supply arm 118 positioned above the polishing pad 110, which can be used to supply a polishing fluid to the polishing pad 110, and a pad conditioning assembly 120 positioned above the polishing pad 110, facing the polishing pad 110.

[0019]

[0026] In a typical CMP process, a rotating and / or swept substrate carrier 108 exerts a downforce on a substrate 112 (shown in phantom) disposed therein, pressing the material surface of the substrate 112 against the polishing pad 110 as the polishing pad 110 rotates beneath the substrate carrier 108. The substrate 112 is pressed against the polishing pad 110 in the presence of one or more polishing fluids supplied by a fluid supply arm 118. Typical polishing fluids include aqueous slurries with abrasive particles suspended therein. Often, the polishing fluids contain pH adjusters and other chemically active components, such as oxidizers, to enable chemical-mechanical polishing of the material surface of the substrate 112.

[0020]

[0027] A pad conditioning assembly 120 is used to press a fixed polishing conditioning disk 122 against the surface of a polishing pad 110 that rotates below the pad conditioning assembly 120 before, after, or during polishing of a substrate 112. Conditioning the polishing pad 110 with the conditioning disk 122 maintains the polishing pad 110 in a desired condition by abrading, activating, and removing polishing by-products and other debris from the polishing surface of the polishing pad 110.

[0021]

[0028] In some embodiments, the polishing system 100 further includes a process endpoint detection system 125. The process endpoint detection system 125 is used to monitor the thickness of a material layer or the removal of a material layer from the field surface of the substrate 112 during the polishing process. The process endpoint detection system 125 includes one or more sensors, such as eddy current sensors or optical sensors, housed within a cavity 130 (FIG. 1B) of the platen assembly 102.

[0022]

[0029] The platen assembly 102 (FIGS. 1A-1C) includes a lower platen 104 and a polishing platen 106 disposed on and coupled to the lower platen 104. Here, the lower platen 104 has a top-down circular shape, an annular polishing platen mounting surface 126, and one or more concave surfaces 146 disposed radially inward from the polishing platen mounting surface 126. The one or more concave surfaces 146, together with the polishing platen 106, define a cavity 130. The polishing platen 106 is disposed on the polishing platen mounting surface 126 and secured thereto using a plurality of fasteners 138, where the plurality of fasteners are disposed through corresponding openings formed in an annular flange-shaped portion 140 of the lower platen 104.

[0023]

[0030] The polishing platen 106 is formed of a cylindrically shaped platen body 142 and includes a low-adhesion material coating layer 144 formed on one or more surfaces of the platen body 142. For example, here, the platen body 142 has a first surface (platen body surface 132), a second surface 134 opposite and generally parallel to the platen body surface 132, and a radially outward circumferential surface 136 connecting the platen body surface 132 to the second surface 134. The material coating layer 144 is formed on the platen body surface 132 to provide a low-adhesion pad mounting surface 148 and is further formed on the circumferential surface 136 to protect the platen body 142 from corrosion caused by the polishing fluid. In some embodiments, the polishing platen 106 includes an aperture 124, such as a window, formed therethrough. An endpoint detection system 125 can be used to monitor the substrate undergoing the polishing process using one or more sensors positioned proximate to the apertures 124 .

[0024]

[0031] The polishing platen assembly 102, and thus the polishing platen 106, can be appropriately sized for any desired polishing system. For example, here, a size for a multi-platen polishing system configured to polish a 300 mm diameter substrate has a diameter greater than about 300 mm, such as between about 500 mm and about 1000 mm, or greater than about 500 mm. Typically, the polishing platen 106 is relatively thin, having a thickness between about 20 mm and about 150 mm, or about 100 mm or less, e.g., about 80 mm or less, about 60 mm or less, or about 40 mm or less. Appropriate adjustments to the size of the polishing platen 106 can be made for polishing systems configured to polish substrates of different sizes, such as 200 mm or 450 mm diameter substrates, or for polishing platens 106 sized to polish multiple substrates simultaneously. In some embodiments, the ratio of diameter to thickness of the polishing platen 106 is about 3:1 or greater, about 5:1 or greater, about 10:1 or greater, about 15:1 or greater, about 20:1 or greater, about 25:1 or greater, about 30:1 or greater, about 40:1 or greater, or, for example, about 50:1 or greater.

[0025]

[0032] The platen body 142 is formed of a suitably hard, lightweight, and abrasive fluid-corrosion-resistant material, such as aluminum, an aluminum alloy (e.g., 6061 aluminum), or stainless steel. The coating layer 144 typically comprises a polymeric material made from one or more fluorine-containing polymer precursors or melt-processable fluoropolymers, such as perfluoroalkoxy polymers (PFAs), fluorinated ethylene-propylene (FEP), monofluoroalkyl polymers (MFAs), tetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVF), and copolymers made from combinations of two or more of these polymer precursors. In some embodiments, the coating layer 144 is formed from a perfluoroalkoxyalkane (PFA), for example, a copolymer of tetrafluoroethylene and one or more perfluoroethers (C2F3ORf, where Rf is a perfluorinated group such as trifluoromethyl (CF3)). In other embodiments, material coating layer 144 may be formed from polyphenylene sulfide (PPS), polyetheretherketone (PEEK), thermoplastic polyimide (TPI), polyetherimide (PEI), polyamideimide (PAI), liquid crystal polymer (LCP), combinations thereof, and / or one or more fluorine-containing polymers.

[0026]

[0033] Herein, material coating layer 144 is formed by forming a first polymer layer 150 (shown in phantom in FIG. 1C ) on the surface of platen body 142, and then removing portions of first polymer layer 150 to provide pad mounting surface 148 with a desired flatness or shape. Examples of suitable methods that may be used to form first polymer layer 150 include dipping, spraying, e.g., plasma spray coating or thermal spray coating, and electrostatic deposition of a liquid or powdered polymer precursor. In some embodiments, forming first polymer layer 150 includes heating platen body 142 and the polymer or polymer precursor deposited thereon to a temperature greater than about 250° C., e.g., greater than about 300° C., or greater than about 350° C.

[0027]

[0034] In some embodiments, the first polymer layer 150 has a thickness t of about 100 μm or more, such as about 120 μm or more, about 140 μm or more, about 160 μm or more, about 180 μm or more, e.g., about 200 μm or more. i Here, the first polymer layer 150 is formed to have a thickness t i is substantially uniform across the platen body surface 132 disposed thereunder. For example, in one embodiment, the thickness t of the first polymer layer 150 obtained in uniform increments across the diameter of the platen body surface 132 is i The standard deviation σ of multiple measurements of is less than about 10 μm, such as less than about 9 μm, less than about 8 μm, less than about 7 μm, less than about 6 μm, or such as less than about 5 μm.

[0028]

[0035] In some embodiments, the platen body surface 132, and therefore the surface of the first polymer layer 150, suffers from a lack of flatness, where at least some portions of the surface of the first polymer layer 150 deviate from a reference plane, such as a least-squares reference plane, by about 50 μm or more, about 75 μm or more, about 100 μm or more, about 150 μm or more, about 175 μm or more, about 200 μm or more, or about 25 μm or more, such as between about 25 μm and about 200 μm. Thus, in some embodiments, after the first polymer layer 150 is formed on the platen body 142, at least a portion of it is removed to form the second polymer layer, herein material coating layer 144. Removing at least a portion of the first polymer layer 150 forms a polishing platen 106 having a pad mounting surface 148 with a desired flatness or surface topography. A method for removing at least a portion of the first polymer layer 150 to form a polishing platen 106 having a desired flatness or surface topography is illustrated in FIG.

[0029]

[0036] Figure 2 illustrates a method 200 for forming a desired shape on a pad mounting surface of a polishing platen, according to one embodiment. Figure 3 illustrates a manufacturing system 300, according to one embodiment, that can be used to implement method 200.

[0030]

[0037] In operation 202, the method 200 includes placing a polishing platen 310 on a production support of a manufacturing system 300, such as a lathe or milling machine, used to shape metal or other rigid materials. Here, the manufacturing system 300 is a vertical turning lathe. The vertical turning lathe includes a support spindle 302 rotatable about a spindle axis 304, a fixture 306 secured to the support spindle 302, and a cutting tool 308 positioned above and facing the support spindle 302. Here, the fixture 306 is substantially similar to or identical to the lower platen 104 described above in FIGS. 1A-1B. The polishing platen 310 is secured to the fixture 306 using a plurality of fasteners 312. The plurality of fasteners 312 are adjustable in the Z direction to pull or push the outer radius of the fixture 306, and therefore the polishing platen 310, toward or away from the support spindle 302. In some embodiments, the manufacturing system 300 further includes a surface profiler 314, such as a dial gauge, coupled to the cutting tool 308. The surface profiler 314 can be used to measure the flatness of the polishing platen 310 before, during, and after modifying the surface profile of the polishing platen 310.

[0031]

[0038] In operation 204, the method 200 includes removing at least a portion of the first polymer layer 150 using a cutting tool 308 to provide the pad mounting surface 148 with a desired flatness or surface topography. Here, removing at least a portion of the coating layer includes moving one or both of the cutting tool 308 and the polishing platen 310 while maintaining a desired distance in the Z direction between them to control the depth of material removal. Here, the cutting tool 308 is configured to move radially inward from the outer diameter of the polishing platen 310 to at least its center (or vice versa) while rotating the polishing platen 310 underneath. Thus, the relative movement of the polishing platen 310 and the cutting tool 308 results in a spiral-shaped cutting path from the surface of the polishing platen 310. In this case, the spiral pattern extends from a central region (e.g., a central axis) of the polishing platen 310 to the outer edge of the polishing platen 310. In other embodiments, such as those in which the machine tool is a mill including an XY translation stage, the milling cutting tool and polishing platen 310 may produce a raster-shaped cutting path from the surface of the polishing platen.

[0032]

[0039] The method 200 can be used to modify the profile of the pad mounting surface 148 of the polishing platen 106 to any desired shape (such as substantially planar, convex, or concave).

[0033]

[0040] In some embodiments, method 200 can be used to form a substantially planar pad mounting surface 148, where the standard deviation of multiple measurements taken at regular intervals across the pad mounting surface 148 from a least-squares reference plane of the pad mounting surface 148 is about 25 μm or less. In these embodiments, removing portions of the first polymer layer 150 to provide the substantially planar pad mounting surface 148 results in a variation in thickness of the coating layer 144 across the diameter of the polishing platen 106. For example, the platen body surface 132 of the portion of the polishing platen 106 shown in FIG. 1C has a concave surface profile, and the first polymer layer 150 disposed on the platen body surface 132 has a uniform thickness t i 1C, the surface of the material coating layer 144 has a concave surface profile, and the surface of the material coating layer 144 has a substantially planar profile. In FIG. 1C, the non-uniform thickness (t 2- t1). Thus, in some embodiments, the variation in thickness of the material coating layer 144 across the diameter of the pad mounting surface 148 is non-zero. For example, in some embodiments, the variation in thickness of the coating layer 144 across the pad mounting surface 148 is about 10 μm or more, such as about 20 μm or more, about 30 μm or more, about 40 μm or more, or about 50 μm or more. Typically, the coating layer 144 has a minimum thickness of about 25 μm or more, such as about 50 μm or more, and a maximum thickness of about 250 μm or less.

[0034]

[0041] In some embodiments, the method 200 can be used to form a pad mounting surface 148 having a concave or convex shape, such as the substantially concave shape shown in FIG.

[0035]

[0042] In some embodiments, the method 200 further includes forming a desired shape on the platen body surface 132 before forming the first polymer layer 150 on the platen body surface 132. For example, in some embodiments, the method 200 may include machining the platen body 142 to form a concave or convex shape on the platen body surface 132 before forming the first polymer layer 150 on the platen body surface 132, as shown in Figures 5D-5E.

[0036]

[0043] FIG. 4 is a graph 400 depicting the profile of a pad mounting surface of a polishing platen formed according to method 200. The polishing platen in FIG. 4 is sized for use in a multi-platen system, with each platen sized to polish a single 300 mm diameter substrate. The polishing platen is formed with a polishing pad mounting surface 405 having a radius of approximately 380 mm and including a substantially concave shape with a height difference between the center of the pad mounting surface 405 and the edge of the pad mounting surface of approximately 76 μm. Here, measurements taken along the radius of the pad mounting surface 405 deviate from a circular convex curve 410 having a radius R1 by approximately 5 μm or less. Beneficially, method 200 herein can be used to form pad mounting surfaces having substantially concave or substantially convex shapes, where multiple measurements taken at equal intervals across the radius of the pad mounting surface have an average deviation of approximately 20 μm or less, such as approximately 15 μm or less, approximately 10 μm or less, or approximately 5 μm or less, from the desired shape's radius of curvature R1.

[0037]

[0044] 5A is a schematic cross-sectional view of a polishing platen 500a including a platen body 502a having a first polymer layer 504a formed thereon. The platen body 502a and first polymer layer 504a may be the same as or substantially similar to the platen body 142 and first polymer layer 504a described above in FIGS. 1A-1C. For example, in FIG. 5A, the first polymer layer 504a has the same uniformity and thickness t as the first polymer layer 150 described above in FIG. 1C. i having a substantially uniform thickness t iAs shown, the surface 506 of the platen body 502a is substantially planar, i.e., flat, and therefore the surface 508a of the polymer layer 504a is also substantially flat. However, embodiments herein contemplate that the surface of the platen body 502a may include any one or combination of shapes, such as a hyperbolic parabolic shape (sometimes referred to as a saddle shape or potato chip shape), or a randomly undulating surface shape. In examples of a hyperbolic parabolic shape or a randomly undulating surface shape, a cross-sectional view of the platen body 502a may have both a concave and a convex profile (depending on where the cross-sectional line is taken).

[0038]

[0045] 5B-5C are schematic cross-sectional views of polishing platens 500b-c, respectively, formed by removing at least a portion of first polymer layer 504a using method 200. In FIG. 5B, a portion of first polymer layer 504a (shown in phantom) has been removed to form coating layer 504b, which provides pad mounting surface 508b. Pad mounting surface 508b is formed to have a substantially radially symmetric convex shape having a radius of curvature R1 across the diameter of polishing platen 500b. In this embodiment, the height h, measured from the center C of concave pad mounting surface 508b to a location disposed proximate to the periphery E of pad mounting surface 508b, is about 10 μm or greater, e.g., about 20 μm or greater, about 30 μm or greater, about 40 μm or greater, about 50 μm or greater, about 60 μm or greater, or, for example, about 70 μm or greater. Here, center C of pad mounting surface 508b is coplanar with reference plane P. The pad mounting surface 508b is spaced from the reference plane P by a distance Z2 around a radius proximate the periphery of the pad mounting surface 508b, where the distance Z2 is substantially the same around that radius such that the reference plane P is parallel to the pad mounting surface 508b around that radius proximate the periphery. In this embodiment, the distance Z2 is the same as the height h.

[0039]

[0046] where the thickness t of the coating layer 504b at the center C of the polishing platen 502b or at a first radius adjacent thereto isc is the thickness t of the coating layer 504b at or adjacent the periphery E of the polishing platen 502b. e In some embodiments, the thickness t c and thickness t e is about 10 μm or more, for example, about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, about 70 μm or more, about 80 μm or more, or about 90 μm or more.

[0040]

[0047] 5C, portions of the first polymer layer 504a (shown in phantom) are removed to form a coating layer 504c. The coating layer 504c provides a pad mounting surface 508c having a substantially radially symmetric concave shape with a radius of curvature R1 across the diameter of the polishing platen 500c, where the difference in height h of the pad mounting surface 508c measured from the center C to the periphery E of the polishing platen 500c is about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, or, for example, about 70 μm or more. Here, the thickness t of the coating layer 504c at the center C of the polishing platen 500c is c is the thickness t of the coating layer 504c at or near the periphery E of the polishing platen 500c. e In some embodiments, the thickness t c and thickness t e is about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, about 70 μm or more, about 80 μm or more, or about 90 μm or more. In this embodiment, the center C of the pad mounting surface 508c is spaced from the plane P by a distance Z1, which is equal to the height h. The pad mounting surface 508c is coplanar with the plane P at a radius proximate the periphery E of the pad mounting surface 508c.

[0041]

[0048] Typically, R1 is expressed by the formula R 12= (R1 - h)2 + r2, where r is the radius of the polishing platen. In one example, the radius of curvature R1 is approximately 952 mm for a 381 mm platen (radius) with either a substantially concave or convex pad mounting surface 508b,c and a height h of approximately 76 μm.

[0042]

[0049] 5D-5E are schematic cross-sectional views of polishing platens 500d-e, respectively, formed by removing at least a portion of first polymer layer 504a (shown in phantom) using method 200. FIGS. 5D-5E illustrate that the desired shape for polishing pad mounting surfaces 508d-e can be formed independently of the shape of surface 506 of platen body 502b disposed thereunder. In FIG. 5D, polishing platen 500d includes platen body 502b having surface 506 including a convex shape with radius of curvature R2. Here, coating layer 504d is formed by removing a portion of first polymer layer 504a. Coating layer 504d includes pad mounting surface 508d having a radially symmetric convex shape as described in FIG. 5B. Radius of curvature R2 may be the same as, greater than, or smaller than radius of curvature R1. In FIG. 5E, a polishing platen 500e includes a platen body 502b, and a portion of a first polymer layer 504a is removed to form a coating layer 504e and a pad mounting surface 508e having a radially symmetric concave shape as described in FIG. 5C.

[0043]

[0050] In some embodiments, the polishing platens 500d-e are formed to have a desired radially symmetric convex shape (as shown) or a desired radially symmetric concave shape (not shown) by machining the surface 506 of the platen body 502b before forming the first polymer layer 504a on the platen body 502b. By machining the surface 506 of the platen body 502b to obtain the desired radially symmetric shape before forming the first polymer layer 504a, the thickness of the first polymer layer 504a required to form the desired concave or convex pad mounting surfaces 508d, e is beneficially reduced. For example, as shown in FIG. 5E, if a concave pad mounting surface 508e is desired, the platen body 502b may be machined to have a substantially concave surface (not shown) before forming the first polymer layer 504a. By machining the pad mounting surfaces 508d, e before forming the first polymer layer 504a on the surface 506 of the platen body 502b, the possibility of mismatch of the desired shape between the pad mounting surface 508e and the surface 506 of the platen body 502b is reduced, as shown in, for example, FIG. 5E.

[0044]

[0051] 5E, the surface 506 of the platen body 502b has a surface shape that may result from deformation of the platen body 502b during the relatively high temperature process used to form the first polymer layer 504a on the surface 506. As a result, the initial thickness t of the first polymer layer 504a required to form the desired concave pad mounting surface 508e is reduced. iis greater than what may be required if the underlying surface 506 of the platen body 502b has a generally concave shape. Thus, in embodiments in which a convex or concave pad mounting surface 508e is desired, forming a generally radially symmetric convex or concave shape on the surface 506 of the platen body 502b reduces the likelihood of an inconsistent surface shape after formation of the first polymer layer 504a. By reducing the likelihood of an inconsistent surface shape after the relatively high temperature formation process of the first polymer layer 504a, beneficially, the initial thickness t required for the first polymer layer 504a to achieve the desired shape of the pad mounting surface 508e is reduced. i is reduced.

[0045]

[0052] 5F-5H are schematic cross-sectional views of respective polishing platens 500f-h illustrating alternative shapes of the pad mounting surfaces 508f-h that can be formed in the respective coating layers 504f-h using the methods described herein. In FIGS. 5F-5H, the shapes of the pad mounting surfaces 508f-h are formed by removing at least a portion of the first polymer layer 504a (shown in FIG. 5A) using the methods described herein. In other embodiments, the shapes of the pad mounting surfaces 508f-h can be formed by machining the surface 506 of the platen body 502a to have the desired shape before forming the first polymer layer 504a on the surface 506 of the platen body 502a. In some embodiments, the desired shape of the pad mounting surfaces 508f-h is formed by both machining the surface 506 and removing at least a portion of the formed first polymer layer 504a on the surface 506. In some embodiments, the profile of surfaces 508f-h measured relative to reference plane P includes one or more radially symmetric features, desirably formed by machining surface 506 and / or removing at least a portion of first polymer layer 504a formed on surface 506. As shown in Figures 5F-5H, surfaces 508f-h can include at least one of a radially symmetric depression D (Figure 5F) and a radially symmetric peak PK (Figure 5G) disposed between the center C and edge E of platen 500g. The radially symmetric depression and the radially symmetric peak thus form an annular feature symmetric about the central axis C of the platen.

[0046]

[0053] In FIG. 5F, pad mounting surface 508f is located at platen radius r p and the reference plane P has a radius r p or radius r pand is coplanar with the pad mounting surface 508f. The center C of the pad mounting surface 508f is disposed below the plane P and is spaced from the plane P by a distance Z1 of about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, or e.g., about 70 μm or more. In other embodiments, the center C of the pad mounting surface 508f extends above the plane P by a distance of about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, or e.g., about 70 μm or more. In other embodiments, the center C of the pad mounting surface 508f is substantially coplanar with the plane P.

[0047]

[0054] Here, the pad mounting surface 508f includes an annular portion (at radius r1) disposed between a center C or a radius proximate thereto of the pad mounting surface 508f and a periphery E or a radius proximate thereto. The annular portion is spaced from the plane P by a distance Z3 greater than distance Z1, i.e., the annular portion of the pad mounting surface 508f at radius r1 is lower than both the center C or a first radius proximate thereto of the pad mounting surface 508f and the periphery E or a radius proximate thereto. Here, distance Z3 is about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, or, for example, about 70 μm or more. In some embodiments, the low point of the annular portion, here at radius r1, is disposed between about one-third and about two-thirds of the radial distance from the center C to the periphery E.

[0048]

[0055] In some embodiments, for example, when the pad mounting surface 508f is formed by removing at least a portion of the polymer layer 504a (FIG. 5A) formed on the platen body 502a, the thickness t3 at the third radius is less than the thickness t c and t e In some embodiments, the thickness t3 and the thickness t c and thickness t eis about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, about 70 μm or more, about 80 μm or more, or about 90 μm or more.

[0049]

[0056] Here, the center C of the pad mounting surface 508f is disposed below the plane P and is spaced from the plane P by a distance Z1 of about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, e.g., about 70 μm or more. In other embodiments, the center C of the pad mounting surface 508f extends above the plane P by a distance of about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, or e.g., about 70 μm or more. In other embodiments, the center C of the pad mounting surface 508f is substantially coplanar with the plane P.

[0050]

[0057] The location of the reference plane P relative to the top surfaces of the pad mounting surfaces 508b-h described herein is not particularly limiting, and descriptions of surface heights above or below the reference plane P may be modified to that definition. For example, in an alternative description of Figure 5F, a reference plane (not shown) may be defined as being coplanar with the pad mounting surface 508f at radius r1, and therefore the surface heights of both the center C and periphery E of the pad mounting surface 508f may be above the reference plane.

[0051]

[0058] 5G , the pad mounting surface 508g includes an annular portion (at a third radius r1) disposed between a first radius at or adjacent to the center C of the pad mounting surface 508 and a second radius at or adjacent to the periphery E of the pad mounting surface 508. The annular portion is coplanar with the reference plane P. The pad mounting surface 508g at the first radius at or adjacent to the center C is disposed below the reference plane P and is spaced apart from the reference plane P by a distance Z1. The pad mounting surface 508g at a radius at or adjacent to the periphery E of the pad mounting surface is disposed below the reference plane P and is spaced apart from the reference plane P by a distance Z2, which may be the same or different from the distance Z1. Thus, the annular portion of the pad mounting surface 508g at the third radius r1 is higher than both the center C of the pad mounting surface 508g or the first radius at or adjacent to the center C and the second radius at or adjacent to the periphery E of the pad mounting surface 508g. Here, the distance Z1 is about 10 μm or more, e.g., about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, or for example, about 70 μm or more. In some embodiments, the annular portion at the third radius r1 is disposed between about 1 / 3 and about 2 / 3 of the radial distance from the center C to the circumferential edge E.

[0052]

[0059] In some embodiments, for example, when the pad mounting surface 508g is formed by removing at least a portion of the polymer layer 504a (FIG. 5A) formed on the platen body 502a, the thickness t3 at the third radius is equal to the thickness t c and t e In some embodiments, the thickness t3 and the thickness t c and thickness t e is about 10 μm or more, for example, about 20 μm or more, about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, about 70 μm or more, about 80 μm or more, or about 90 μm or more.

[0053]

[0060] In Figure 5H, at least a portion of the pad mounting surface 508h slopes upward from a first radius at the periphery E to a second radius r1 located at or adjacent to the center C. The reference plane P is aligned along the radius of the pad mounting surface 508h, e.g., at the radius r p , parallel to the surface of the pad mounting surface 508h, where the pad mounting surface 508h has a generally conical shape when viewed in cross section, whereby the circular portion of the pad mounting surface 508h is concentrically disposed about a center C, and the circular portion of the pad mounting surface 508h having a radius r1 is coplanar with the reference plane P. Here, the thickness t c and t e and distance Z2 may be in the same range as any one or more combinations of the other embodiments described herein.

[0054]

[0061] In some embodiments, the thicknesses of the coating layer at various radial locations from the center C of the pad mounting surface described herein are averaged from multiple thickness measurements taken at corresponding multiple equidistant locations along each radius. For example, the thicknesses described herein may be averaged from three or more thickness measurements (e.g., measurements from four or more equidistant locations, or from five or more equidistant locations, etc.) taken at locations that are equidistant from each other when measured along each radius.

[0055]

[0062] In some embodiments, distances Z1, Z2, and Z3 of pad mounting surfaces 508b-h from plane P at various radial locations from center C are averaged from multiple measurements taken at corresponding multiple equidistant locations along each radius. For example, distances Z1, Z2, and Z3 may each be averaged from three or more measurements (e.g., measurements from four or more equidistant locations, or from five or more equidistant locations, etc.) taken at equidistant locations measured along each radius.

[0056]

[0063] FIG. 6 illustrates a method of polishing a substrate using a polishing platen formed according to embodiments described herein. In operation 602, method 600 includes pressing a substrate against a polishing pad in the presence of a polishing fluid, where the polishing pad is disposed on the polishing platen. The polishing platen may be formed according to any one or combination of embodiments described herein. The polishing platen includes a cylindrical metal body having a low-adhesion material coating layer formed thereon. The coating layer is disposed on the surface of the metal body to form a polishing pad mounting surface, where the height difference between the center of the pad mounting surface and a position along a radial direction outward from the center is about 25 μm or greater. The coating layer may be formed to provide a pad mounting surface having any of the shapes and / or characteristics described above.

[0057]

[0064] Embodiments herein provide for the manufacture of polishing platens having low-adhesion material surfaces with controlled and repeatable flatness profiles and / or other desired surface topography. Advantageously, the polishing platens herein can be formed with convex or concave shapes that can be used to fine-tune the polishing performance of one or more individual polishing systems for a particular substrate polishing process.

[0058]

[0065] While the forgoing description is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is defined by the claims that follow.

Claims

1. a cylindrical metal body having an upper platen surface and a center, the cylindrical metal body configured to rotate about the center; and a polymeric coating layer disposed on the upper platen surface of the cylindrical metal body to form a circular pad mounting surface having a first surface height at a first radius, a second surface height at a second radius, and a third surface height at the center; the polymer coating layer comprises a fluoropolymer; both the first radius and the second radius are disposed outward from the center, and the second radius is disposed radially outward from the first radius; the first surface height and the second surface height are measured as distances from a reference plane that is a plane passing through the top of the pad attachment surface, and the distance between the first surface height and the second surface height is 25 μm or more; the pad mounting surface has a convex portion at the center and the second radius and a concave portion at the first radius; The polishing platen, wherein the polymer coating layer is further disposed on a radially outward circumferential surface of the cylindrical metal body to form a continuous polymer coating layer.

2. the second surface height is coplanar with the reference surface; The polishing platen of claim 1 , wherein the first surface elevation and the third surface elevation are both located below the reference surface.

3. a cylindrical metal body having an upper platen surface and a center, the cylindrical metal body configured to rotate about the center; and a polymeric coating layer disposed on the upper platen surface of the cylindrical metal body to form a circular pad mounting surface having a first surface height at a first radius, a second surface height at a second radius, and a third surface height at the center; the polymer coating layer comprises a fluoropolymer; both the first radius and the second radius are disposed outward from the center, and the second radius is disposed radially outward from the first radius; the first surface height and the second surface height are measured as distances from a reference plane which is a plane passing through the top of the pad attachment surface, and the distance between the first surface height and the second surface height is 25 μm or more; the pad mounting surface has a concave shape at the center and the second radius and a convex shape at the first radius; The polishing platen, wherein the polymer coating layer is further disposed on a radially outward circumferential surface of the cylindrical metal body to form a continuous polymer coating layer.

4. The polishing platen of claim 3 , wherein the first surface elevation is coplanar with the reference surface, and the second surface elevation and the third surface elevation are both located below the reference surface.

5. the polymer coating layer has a first thickness at the first radius and a second thickness at the second radius; The polishing platen of claim 1 , wherein the difference between the first thickness and the second thickness is 25 μm or greater.

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