CMP polishing pad having a protruding structure with a designed opening void space

Abstract

To provide a polishing pad useful in chemical mechanical polishing.SOLUTION: The polishing pad comprises a base pad 12 having a top side, and a plurality of protruding structures 10 on the top side of the base pad, each of the protruding structures having a body. The body has (i) an exterior perimeter surface 14 defining an exterior shape of the protruding structure, (ii) an interior surface defining a central cavity, and (iii) a top surface defining an initial polishing surface area. The body further has openings 18 in it from the cavity to the exterior perimeter surface.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Field of the Invention The present invention generally relates to the field of polishing pads for chemical mechanical polishing. In particular, the present invention relates to a chemical mechanical polishing pad having a polishing structure useful for chemical mechanical polishing of magnetic, optical and semiconductor substrates, including front end of line (FEOL) or back end of line (BEOL) processing of memory and logic integrated circuit substrates.

Background Art

[0002] Background In the manufacture of integrated circuits and other electronic devices, multiple layers of conductive, semiconductor, and insulating materials are deposited on the surface of a semiconductor wafer and then partially or selectively removed therefrom. Thin layers of conductive, semiconductor, and insulating materials may be deposited using a number of deposition techniques. Common deposition techniques in current wafer processing include, among others, physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), and electrochemical plating (ECP). Common removal techniques include, among others, wet and dry etching; isotropic and anisotropic etching.

[0003] As layers of material are sequentially deposited and removed, the top surface of the wafer becomes non-flat. Since subsequent semiconductor processing (e.g., photolithography, metallization, etc.) requires the wafer to have a flat surface, it is necessary to planarize the wafer. Planarization is useful for removing undesirable surface topography and surface defects (such as rough surfaces, agglomerated materials, crystal lattice damage, scratches, and contaminated layers or substances). In addition, in a damascene process, material is deposited to fill the recessed regions created by patterned etching, but the filling process can be inaccurate and overfilling is preferred over underfilling of the recesses. Therefore, the material outside the recess needs to be removed.

[0004] Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize or polish a workpiece such as a semiconductor wafer and to remove excess material in a damascene process. In conventional CMP, a wafer carrier, or polishing head, is mounted on a carrier assembly. The polishing head holds the wafer and positions it in contact with the polishing surface of a polishing pad mounted on a table or platen within a CMP apparatus. The carrier assembly provides an adjustable pressure between the wafer and the polishing pad. At the same time, a slurry or other polishing medium is dispensed onto the polishing pad and drawn into the gap between the wafer and the polishing layer. To achieve polishing, the polishing pad and the wafer typically rotate relative to each other. When the polishing pad rotates beneath the wafer, the wafer typically traverses an annular polishing track, or polishing zone, where the surface of the wafer faces directly against the polishing layer. The wafer surface is polished and planarized by the chemical and mechanical action of the polishing surface and the polishing medium (e.g., slurry) thereon.

[0005] The interaction between the polishing layer, polishing medium, and wafer surface in CMP has been the subject of increasing research, analysis, and advanced numerical modeling in recent years, with the aim of optimizing polishing pad design. Most of the polishing pad development has been, in fact, experimental, involving trials of many different porous and non-porous polymeric materials and the mechanical properties of such materials since the inception of CMP as a semiconductor manufacturing process. Some approaches involve providing various protruding structures on the polishing pad that extend from the base of the pad. See, for example, U.S. Patent Nos. 6,817,925; 7,226,345; 7,517,277; 9,649,742; U.S. Patent Publication No. 2014 / 0273777; U.S. Patent No. 6,776,699. Other approaches use a lattice structure that can form a generally monolithic structure with voids. See, for example, U.S. Patent Nos. 7,828,634; 7,517,277; or 7,771,251. CN 20190627407 discloses a polishing structure having recessed portions and hollow protrusions (where the hollow region can be opened at the top by removal of the upper surface of the protrusion during polishing). The upper opening can allow for the collection of slurry particles and polishing debris that can cause polishing defects.

[0006] U.S. 2019 / 0009458 discloses the use of additive manufacturing (i.e., 3D printing) to create a composite single unitary structure such as one having (a) a body portion having a surface portion thereon; and (b) at least a first array of feature elements formed on the surface portion. Each of the feature elements includes: (i) a support structure coupled to and extending upwardly from the surface portion; and (ii) an upper segment coupled to the support structure, the upper structure and the support structure together defining an internal cavity formed therein. These structures are disclosed as being crushable under pressure and then returning to their previous configuration. The structures are disclosed as being useful for noise and vibration damping and skin-body contact applications. SUMMARY OF THE INVENTION

[0007] Disclosed herein is a polishing pad useful in chemical mechanical polishing, including a base pad and a plurality of protruding structures on the base pad, each of the protruding structures having a body, where the body has (i) an outer peripheral surface defining the outer shape of the protruding structure, (ii) an inner surface defining one or more central cavities, and (iii) an upper surface defining an initial polishing surface area, where the body further has an opening therein from the cavity to the outer peripheral surface.

[0008] Further disclosed is a method of polishing using such a polishing pad.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0010] Detailed Description of the Invention The polishing pads disclosed herein include a base pad having a plurality of protruding structures thereon. The protruding structures have at least one central cavity opening at the upper part of the structure and have an opening from the cavity of the protruding structure to the outer periphery (i.e., a side opening or a wall opening).

[0011] Such pads can provide certain advantages. Specifically, its design provides a relatively high surface polishing surface area (which is also referred to as the contact area as it is the part of the pad that contacts the surface to be polished), while at the same time, voids (e.g., cavities and / or openings) enable good management / transport of the typically used polishing fluid. This fluid management feature can be useful for controlling temperature, for example, during polishing, to reduce or limit the temperature rise caused by frictional heating. Lower polishing temperatures can help maintain the mechanical properties of the polishing pad and can help avoid irreversible thermally induced chemical reactions in the pad or the substrate being polished. Chemical reactions in the pad can increase the likelihood of defect generation during polishing.

[0012] Using the central cavity and the side openings (or wall openings) in the body of the protrusion, there can be efficient movement of fluid between the wafer and the protruding structure, thus reducing the time to contact between the pad and the substrate to be polished. This can increase the time the polishing surface is in contact with the wafer and can increase the number of polishing protrusions in contact, both of which can potentially result in a higher removal rate (higher asperity contact efficiency and reduced defectivity (reduced individual asperity contact pressure)). For example, this novel structure approaches the surface at a faster speed than their solid counterparts, as shown in Table 1 (which shows the speed of approach of its features to the substrate).

[0013]

Table 1

[0014] By using voids, pads having a harder or higher rate upper polishing surface while having a lower total compression rate can be applied to the substrate to be polished. The lower rate can improve the form of the pad with respect to the substrate to be polished. For example, the effective compression rate of the pad is at least 0.1%, at least 1%, at least 10%, at least 20% or at least 25% of the rate of a pad made using a solid protrusion having the same external dimensions and the same material as used in making the protrusion structures disclosed herein, up to 100%, up to 90%, up to 80%, up to 70%, up to 60%, up to 50% or up to 40%. The effective compression rate of the pad can be measured using a modified version of ASTM D3574. Since the specified thickness of 0.49 inches cannot be achieved, the rate is decelerated from the specified 0.5 inches / minute to 0.04 inches / minute by the deflection rate, and the cross-sectional area of compression is reduced from 1 square inch to 0.125 square inches to reduce the effects of sample thickness variation and curl. An additional capacitance sensor can be added to more accurately measure the strain at a given stress. The effective rate of the pad when measured according to this method can be at least 0.1 megapascal (MPa), at least 1 MPa, at least 5 MPa, at least 10 MPa, at least 20 MPa, at least 40 MPa, at least 50 MPa, at least 70 MPa, or at least 100 MPa, up to 5 gigapascals (GPa), or up to 1 GPa, or up to 700 MPa, up to 500 MPa, up to 300 MPa.

[0015] Protrusion structures having voids and side body openings (i.e., wall openings) can be mechanically more robust as they exhibit less deflection than solid protrusion structures of comparable diameter. The comparable diameter D is such that the comparable diameter D is as follows: D = 2 * [square root of {(initial polishing surface area) / π}] is calculated as calculated as follows. Thus, when the initial polished surface area for the protruding structure is 28.3, a cylindrical structure with a diameter of 3 will be a solid structure of equivalent diameter regardless of the diameter of the protruding structure with voids disclosed herein. The calculated deflection of the solid protruding structure compared to the protruding structure with cavities and openings disclosed herein is shown in FIG. 5. With respect to FIG. 5, the structure is cylindrical, the height is 0.125 inches (0.635 cm), and the applied pressure was 5 pounds per square inch (psi) or 34.5 kPa. This demonstrates that the structures disclosed herein have stronger mechanical properties for equivalent diameters than solid protruding structures. For solid protruding structures with diameters less than 0.5 millimeters (mm), the deflection was not calculated precisely, but it is thought to continue the upward trend shown for solid protruding structures of 0.5 mm and above.

[0016] A pad having a protruding structure with the void design enumerated herein can have a substantially consistent polishing area even if the protrusions wear down during use (when the size and orientation of the wall openings are selected to ensure such consistency).

[0017] Base pad The polishing pad disclosed herein includes a base pad having a protruding structure thereon.

[0018] The base pad or base layer can be a single layer or can include two or more layers. The upper surface of the base pad can define a plane in x-y Cartesian coordinates. The base can be provided on a sub-pad. For example, the base layer can be attached to the sub-pad via a mechanical fastener or by an adhesive. The sub-pad can be made of any suitable material, including, for example, materials useful in the base layer. The base layer in some embodiments can have a thickness of at least 0.5 mm, or at least 1 mm. The base layer in some embodiments can have a thickness of 5 mm or less, 3 mm or less, or 2 mm or less. The base layer can be provided in any shape, although it is conveniently circular or disc-shaped with a diameter in the range of at least 10 centimeters (cm), at least 20 cm, at least 30 cm, at least 40 cm, or at least 50 cm and up to 100 cm, up to 90 cm, or up to 80 cm.

[0019] The base pad or base layer may include any material known for use as a base layer for a polishing pad. For example, it may include polymers, composites of polymer materials and other materials, ceramics, glass, metals, stone, or wood. Polymers and polymer composites can be used as base pads, particularly for the upper layer when there are two or more layers, due to their compatibility with materials that can form protruding structures. Examples of such composites include polymers filled with carbon or inorganic fillers, and fibrous mats of, for example, glass or carbon fibers impregnated with polymers. The base of the pad can be made from a material having one or more of the following properties: a Young's modulus in the range of at least 2 MPa, at least 2.5 MPa, at least 5 MPa, at least 10 MPa, or at least 50 MPa up to 900 MPa, up to 700 MPa, up to 600 MPa, up to 500 MPa, up to 400 MPa, up to 300 MPa, or up to 200 MPa, as measured by, for example, ASTM D412 - 16. The pad having a base can be made from a material having a compression ratio according to ASTM D3574 in the range of at least 2 MPa, at least 2.5 MPa, at least 5 MPa, at least 10 MPa, or at least 50 MPa up to 900 MPa, up to 700 MPa, up to 600 MPa, up to 500 MPa, up to 400 MPa, up to 300 MPa, or up to 200 MPa. The pad having a base can have a Poisson's ratio in the range of at least 0.05, at least 0.08, or at least 0.1 up to 0.6 or up to 0.5, as measured by, for example, ASTM E1320 15; a density of at least 0.4 grams per cubic centimeter (g / cm 3 ) or at least 0.5 g / cm 3 and up to 1.7 g / cm 3 up to 1.5 g / cm 3 up to, or up to 1.3 g / cm 3 and can be made from a material having such a density.

[0020] Examples of such polymeric materials that can be used in the base pad include polycarbonate, polysulfone, nylon, epoxy resin, polyether, polyester, polystyrene, acrylic polymer, polymethyl methacrylate, polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, polybutadiene, polyethyleneimine, polyurethane, polyethersulfone, polyamide, polyetherimide, polyketone, epoxy, silicone, their copolymers (e.g., polyether - polyester copolymer), and combinations or blends thereof.

[0021] The polymer can be polyurethane. Polyurethane can be used alone or can be a matrix of carbon or inorganic fillers and fibrous mats such as glass or carbon fibers. For the purposes of this specification, "polyurethane" is a product derived from bifunctional or polyfunctional isocyanates, such as polyether urea, polyisocyanurate, polyurethane, polyurea, polyurethane urea, their copolymers and their mixtures. Accordingly, the CMP polishing pad may be made by a method that includes: providing an isocyanate - terminated urethane prepolymer; providing a treatment component separately; and combining the isocyanate - terminated urethane prepolymer and the treatment component to form a combination, and then reacting the combination to form a product. It is possible to form the base pad or base layer by grinding a cast polyurethane cake to a desired thickness. Optionally, preheating the cake mold using IR radiation, induction or DC when casting a porous polyurethane matrix can reduce product variability. Optionally, either a thermoplastic or a thermosetting polymer can be used. The polymer can be a cross - linked thermosetting polymer.

[0022] Protrusion structure The protruding structures are on the base pad and protrude from the base pad. They protrude in the z direction from the xy plane defined by the upper surface of the base pad. The protruding structures can be orthogonal (perpendicular) to the xy plane defined by the base pad, or they can be at an angle. They can be integral with the base pad or an upper layer of the base pad, or they can be separate and adhered to the base pad. They can be of the same material as the base pad or a different material from the base pad.

[0023] The protruding structures are characterized by an outer peripheral surface that defines the outer shape of the protruding structure, an inner surface that defines one or more central cavities, and an upper surface that defines an initial polishing surface area A ips and an upper surface that defines a subsequent polished surface having a subsequent polished surface area A. The protruding structures include openings from the outer periphery to the cavities. As the polishing pad is used, the protruding structures wear down, exposing a new upper surface that defines a subsequent polished surface having a subsequent polished surface area A sps This occurs continuously during polishing. The openings, also referred to as side holes or wall openings, can be positioned within the protruding structures such that as the protruding structures wear down during polishing, the surface available for polishing remains substantially unchanged - i.e., a "substantially constant contact area". For example, the substantially constant contact area can be within 25% or within 10% of the initial polishing surface area A ips of the defined subsequent polished surface area A sps at any point during polishing. Individual protruding structures can have a substantially constant contact area.

[0024] All the pads of its protruding structures can have a substantially constant contact area. For example, individual protruding structures on the pad can have a contact area (i.e., subsequent polished surface area) that changes by more than 25% from the initial polishing surface area if other protruding structures on the pad change in the opposite direction such that the pad as a whole has a substantially constant contact area (i.e., the cumulative subsequent polished surface area of all the protrusions on the pad at a given point in the polishing is different from the cumulative initial polishing surface area by no more than 25% or 10% based on the cumulative initial polishing surface area).

[0025] The contact area ratio is the cumulative surface contact area A b divided by the area A of the base cpsa or a plurality of protruding structures. The cumulative surface contact area can be calculated by adding the areas of all the upper surfaces 11 of the protruding structures. Since the pads are conventionally circular, for the conventional pad shape π(r b ) 2 with respect to, r b is the radius of the pad. For one embodiment, the ratio of A cpsa / A b is at least 0.1, at least 0.2, at least 0.3, or at least 0.4 and is 0.8 or less, 0.75 or less, 0.7 or less, 0.65 or less, or 0.6 or less.

[0026] Figures 1, 3, and 4 show examples of a substantially cylindrical type of protruding structure 10. Figures 3 and 4 show three such structures 10 on a pad 12 having a base. Figure 4 shows a partial view of a polishing pad 1 having a base pad 12 and protruding structures 10. The protruding structure 10 has an outer peripheral surface 14, an upper polishing surface 15, an inner surface 16 defining a cavity 17, and an opening 18. The openings are offset from each other in the vertical and horizontal directions to provide a substantially constant contact area.

[0027] Figure 2 shows an alternative configuration of a protruding structure 20 having an outer periphery with lobes defined by an outer periphery 24, offset openings 28, an inner surface 26, and a cavity 27.

[0028] The protruding structure can have a height of at least 0.05 mm or at least 0.1 mm from the upper surface of the base and up to 3 mm, up to 2.5 mm, up to 2 mm, or up to 1.5 mm. The protruding structure can be perpendicular or substantially perpendicular to its major axis of that height with respect to the surface of the base. Alternatively, the protruding structure can make an angle other than 90 degrees with respect to the surface of the base such that it is inclined or the base is slightly larger or slightly smaller than the initial upper surface.

[0029] The external shape of the protruding structure can be symmetric or asymmetric. Examples of regular shapes include cylindrical, oval, square, regular polygons (equilateral triangle, pentagon, hexagon, heptagon, octagon, etc.), and structures with symmetric lobes. Examples of asymmetric shapes include irregular polygons with sides of different sizes, structures with asymmetric lobes, etc.

[0030] The exterior can be completely convex or can include convex and concave portions. FIG. 1 shows an exterior perimeter that is convex, while FIG. 2 shows an exterior perimeter with convex and concave portions.

[0031] The exterior perimeter can have a maximum dimension (i.e., from a point on the exterior perimeter to the farthest point on the exterior perimeter) of at least 0.2 mm, at least 0.5 mm, at least 0.7 mm, or at least 1 mm, up to 50 mm, up to 20 mm, up to 10 mm, up to 5 mm, up to 3 mm, or up to 2 mm. For example, for a structure having an exterior perimeter with convex and concave portions as shown in FIG. 2, the exterior perimeter can also have a shortest dimension of the cross-section of the structure of at least 0.01 mm, at least 0.05 mm, at least 0.1 mm, or at least 0.5 mm, up to 5 mm, up to 3 mm, up to 2 mm, or up to 1 mm (e.g., the shortest distance that fluid would travel across the upper surface of the protruding structure, e.g., the distance across the upper surface from the exterior perimeter to the cavity).

[0032] The protruding structure includes one or more cavities. The cavity can be defined by the inner surface of the protruding structure. The cavity for each protruding structure can be a single cavity or two or more cavities. If there are two or more cavities for one protruding structure, they may be defined by the inner surface and support ribs, etc. The cavity (or cavities) can extend throughout the height of the protruding structure. The cavity can be open to the surrounding environment at the top of the protruding structure. If two or more adjacent cavities are used, each of the two or more cavities can be open to the surrounding environment at the top of the protruding structure. The cavity can be of any shape. For example, the cavity can be substantially the same shape as the outer perimeter or can be of a different shape. The cavity can be symmetric or asymmetric. Examples of regular shapes include cylindrical, oval, square, regular polygons (equilateral triangle, pentagon, hexagon, heptagon, octagon, etc.), structures with symmetric lobes. Examples of asymmetric shapes include irregular polygons with sides of different sizes, structures with asymmetric lobes, etc. The cavity can have a maximum dimension in the x-y plane (defined by the upper surface of the base pad and / or the upper polishing surface) that is from 20% or 30% to 90%, 80%, 70%, or 60% of the maximum dimension of the protruding structure in that plane. The distance from the outer perimeter to the cavity can be at least 0.05 mm, at least 0.1 mm, at least 0.3 mm, at least 0.5 mm, at least 0.7 mm, at least 1 mm, or at least 1.2 mm and within the range up to 8 mm, up to 7 mm, up to 6 mm, up to 5 mm, up to 4 mm, up to 3 mm, up to 2 mm, or up to 1.8 mm.

[0033] The protruding structure includes one or more openings extending from the outer periphery to the cavity (one or more). The side openings can be offset from each other in the direction of the x-y plane defined by the surface of the base pad. The side openings can be in alternating compartments perpendicular or in the z-direction to the surface of the base pad. FIG. 6 shows a plan view of a portion of the surface of the outer peripheral surface 14 (i.e., as if the outer periphery were spread out in a plane), where the rectangular openings 18 are spaced a distance w in the horizontal direction from each other, and in the vertical direction, one opening ends and the other begins. The side openings can be other shapes such as parallelograms, triangles, irregular shapes, etc., provided that there is sufficient firm support between the openings so as to provide mechanical integrity and a substantially constant contact area, and the side openings are arranged in a complementary manner. The side openings can overlap in the vertical direction as long as the polished surface area is a substantially constant contact area. At a given point in the z-direction, there can be from 0 to 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 80, or 100 openings between the cavity and the outer periphery. The height of the side openings can be from 5%, 10%, 20%, 30% to 90%, 80%, 70%, 60%, 50%, 40% of the total height of the protruding structure (from the upper surface of the base pad to the initial polished surface). The dimensions of the side openings on the outer periphery can be the same as the dimensions of the side openings in the cavity, but will generally be larger than those dimensions. The dimensions of the openings in the x-y plane defined by the surface of the pad having a base can be at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, up to 15 mm, 10 mm, 8 mm, 5 mm, 4 mm at the outer periphery. Inside the inner surface, the dimensions of the side openings (wall openings) in the x-y plane are only about as large as the dimensions of those openings at the outer periphery, and considering the smaller surface area on the inner surface than outside the body (a shorter distance around the cavity relative to the outer periphery of the body), will generally be smaller.Thus, the internal dimensions of the side opening at the internal surface can be from 10%, from 20%, from 30%, or from 40% to 100%, to 90%, to 80%, to 70% of the dimensions of that opening at the external perimeter.

[0034] The polished surface area (initial and / or subsequent) of the protruding structure is from 0.05 mm 2 to 0.1 mm 2 to, or 0.2 mm 2 to 30 mm 2 up to 25 mm 2 up to 20 mm 2 up to 15 mm 2 up to 10 mm 2 up to, or 5 mm 2 and can be within the range up to.

[0035] The void fraction for the protruding structure can be at least 0.1, at least 0.3, at least 0.5 and up to 0.96, up to 0.95, up to 0.90, up to 0.85, or up to 0.80, where the void fraction is calculated by the volume of the cavities and openings divided by the volume defined by the exterior of the protruding structure.

[0036] The protruding structures can be arranged in any configuration on the working surface. In one embodiment, they can be arranged in a hexagonal packing structure oriented in the same direction. In another embodiment, they can be arranged in a radial pattern oriented such that one lobe is aligned with the radiation. The protruding structures do not have to be oriented in any macroscopic orientation. The macroscopic orientation may be adjusted to achieve the desired removal rate, planarization effect, defect control, homogeneity control, and, if desired, the desired slurry volume.

[0037] The protruding structures can be separated from each other - that is, they do not come into direct contact with each other. The distance between adjacent protruding structures can be constant, but it does not have to be. This structure can be arranged at a pitch, which is the distance from the center of one protruding structure to the center of an adjacent protruding structure, from 1 times, 1.5 times, or 2 times to 50 times, 20 times, 10 times, 7 times, 5 times, or 4 times the longest dimension from one point to another on the outer periphery. The pitch (the distance from the center of one protruding structure to the center of an adjacent protruding structure) can be at least 0.7 mm, at least 1 mm, at least 5 mm, at least 10 mm, or at least 20 mm and up to 150 mm, up to 100 mm, up to 50 mm, or up to 30 mm. The distance from the outer periphery of one protruding structure to the closest outer periphery of an adjacent protruding structure can be at least 0.02 mm, at least 0.05 mm, at least 0.1 mm, at least 0.5 mm, or at least 1 mm and up to 100 mm, up to 50 mm, up to 20 mm, up to 10 mm, or up to 5 mm.

[0038] The protruding structure can be formed from any material known to be useful for polishing pads. The composition of the protruding structure may be the same as or different from the base composition. For example, the protruding structure may comprise or consist of a polymeric material. Examples of such polymeric materials include polycarbonate, polysulfone, nylon, polyether, epoxy resin, polyester, polystyrene, acrylic polymer, polymethyl methacrylate, polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, polybutadiene, polyethyleneimine, polyurethane, polyethersulfone, polyamide, polyetherimide, polyketone, epoxy, silicone, their copolymers (e.g., polyether-polyester copolymer), and combinations or blends thereof. The protruding structure may include a composite of a polymeric material and other materials. Examples of such composites include polymers filled with carbon or inorganic fillers. According to certain embodiments, the protruding structure(s) is made from a material having one or more of the following properties: a Young's modulus, as measured by, for example, ASTM D412-16, in the range of at least 2 MPa, at least 2.5 MPa, at least 5 MPa, at least 10 MPa, at least 20 MPa, at least 50 MPa, or at least 100 MPa up to 10 gigapascals (GPa), up to 5 GPa, or up to 1 GPa, or up to 900 MPa, up to 800 MPa, up to 700 MPa, up to 600 MPa, up to 500 MPa, up to 400 MPa, or up to 300 MPa; a density of from 0.4 or 0.5 g / cm 3 to 1.7 or 1.5 or 1.3 g / cm 3 The material of the protruding structure may have a compression ratio, as measured by ASTM D3574, in the range of at least 2 MPa, at least 2.5 MPa, at least 5 MPa, at least 10 MPa, at least 20 MPa, at least 50 MPa, or at least 100 MPa up to 10 gigapascals (GPa), up to 5 GPa, or up to 1 GPa, or up to 900 MPa, up to 800 MPa, up to 700 MPa, up to 600 MPa, up to 500 MPa, up to 400 MPa, or up to 300 MPa.

[0039] The pad may be made by any suitable process. For example, the pad may be made by additive manufacturing by known methods, and the protruding structure may be built on the provided base of the pad by such additive manufacturing, or the entire pad may be made by additive manufacturing.

[0040] When polyurethane is used in the base pad and / or the protruding structure, it can be a reaction product of a polyfunctional isocyanate and a polyol. For example, a urethane prepolymer terminated with polyisocyanate can be used. The polyfunctional isocyanate used in the formation of the polishing layer of the chemical mechanical polishing pad of the present invention can be selected from the group consisting of aliphatic polyfunctional isocyanates, aromatic polyfunctional isocyanates, and mixtures thereof. For example, the polyfunctional isocyanate used in the formation of the polishing layer of the chemical mechanical polishing pad of the present invention can be a diisocyanate selected from the group consisting of 2,4-toluene diisocyanate; 2,6-toluene diisocyanate; 4,4'-diphenylmethane diisocyanate; naphthalene-1,5-diisocyanate; tolidine diisocyanate; paraphenylene diisocyanate; xylylene diisocyanate; isophorone diisocyanate; hexamethylene diisocyanate; 4,4'-dicyclohexylmethane diisocyanate; cyclohexane diisocyanate; and mixtures thereof. The polyfunctional isocyanate can be an isocyanate-terminated urethane prepolymer formed by the reaction of a diisocyanate and a prepolymer polyol. The isocyanate-terminated urethane prepolymer can have unreacted isocyanate (NCO) groups of 2 to 12 wt%, 2 to 10 wt%, 4 to 8 wt%, or 5 to 7 wt%. The prepolymer polyol used to form the polyfunctional isocyanate-terminated urethane prepolymer can be selected from the group consisting of diols, polyols, polyol diols, their copolymers, and mixtures thereof.For example, the prepolymer polyol may be selected from the group consisting of polyether polyols (e.g., poly(oxytetramethylene) glycol, poly(oxypropylene) glycol, and mixtures thereof); polycarbonate polyols; polyester polyols; polycaprolactone polyols; mixtures thereof; and mixtures with one or more low molecular weight polyols selected from the group consisting of ethylene glycol; 1,2-propylene glycol; 1,3-propylene glycol; 1,2-butanediol; 1,3-butanediol; 2-methyl-1,3-propanediol; 1,4-butanediol; neopentyl glycol; 1,5-pentanediol; 3-methyl-1,5-pentanediol; 1,6-hexanediol; diethylene glycol; dipropylene glycol; and tripropylene glycol. For example, the prepolymer polyol may be selected from the group consisting of polytetramethylene ether glycol (PTMEG); ester-based polyols (e.g., ethylene adipate, butylene adipate); polypropylene ether glycol (PPG); polycaprolactone polyols; copolymers thereof; and mixtures thereof. For example, the prepolymer polyol may be selected from the group consisting of PTMEG and PPG. When the prepolymer polyol is PTMEG, the isocyanate-terminated urethane prepolymer may have an unreacted isocyanate (NCO) concentration of 2 to 10 wt% (more preferably 4 to 8 wt%; most preferably 6 to 7 wt%).Examples of commercially available PTMEG-based isocyanate-terminated urethane prepolymers include Imuthane® prepolymers (available from COIM USA, Inc., e.g., PET-80A, PET-85A, PET-90A, PET-93A, PET-95A, PET-60D, PET-70D, PET-75D); Adiprene® prepolymers (available from Chemtura, e.g., LF 800A, LF 900A, LF 910A, LF 930A, LF 931A, LF 939A, LF 950A, LF 952A, LF 600D, LF 601D, LF 650D, LF 667, LF 700D, LF750D, LF751D, LF752D, LF753D and L325); Andur® prepolymers (available from Anderson Development Company, e.g., 70APLF, 80APLF, 85APLF, 90APLF, 95APLF, 60DPLF, 70APLF, 75APLF). When the prepolymer polyol is PPG, the isocyanate-terminated urethane prepolymer can have an unreacted isocyanate (NCO) concentration of 3 to 9 wt% (more preferably 4 to 8 wt%, most preferably 5 to 6 wt%). Examples of commercially available PPG-based isocyanate-terminated urethane prepolymers include Imuthane® prepolymers (available from COIM USA, Inc., e.g., PPT-80A, PPT-90A, PPT-95A, PPT-65D, PPT-75D); Adiprene® prepolymers (available from Chemtura, e.g., LFG 963A, LFG 964A, LFG 740D); and, Andur® prepolymers (available from Anderson Development Company, e.g., 8000APLF, 9500APLF, 6500DPLF, 7501DPLF). The isocyanate-terminated urethane prepolymer can be a low free isocyanate-terminated urethane prepolymer having a free toluene diisocyanate (TDI) monomer content of less than 0.1 wt%. Non-TDI-based isocyanate-terminated urethane prepolymers can also be used.For example, isocyanate-terminated urethane prepolymers include those formed by the reaction of 4,4'-diphenylmethane diisocyanate (MDI) with a polyol such as polytetramethylene glycol (PTMEG), and any diol such as 1,4-butanediol (BDO) is acceptable. When such isocyanate-terminated urethane prepolymers are used, the concentration of unreacted isocyanate (NCO) is preferably 4 to 10 wt% (more preferably 4 to 10 wt%, most preferably 5 to 10 wt%). Examples of commercially available isocyanate-terminated urethane prepolymers in this category include Imuthane® prepolymers (e.g., 27-85A, 27-90A, 27-95A available from COIM USA, Inc.); Andur® prepolymers (e.g., IE75AP, IE80AP, IE 85AP, IE90AP, IE95AP, IE98AP available from Anderson Development Company); and Vibrathane® prepolymers (e.g., B625, B635, B821 available from Chemtura).

[0041] The pads with protrusions disclosed herein surprisingly can have an improved removal rate compared to pads with solid protrusions having the same outer perimeter, even though due to the cavities they would have a smaller polishing surface area. For example, two pads were used for polishing on a CETR brand 8-inch (20.3 cm) polisher using a 2-inch (5.1 cm) tetraethylortho silicate wafer. Klebosol® II1730, a colloidal silica slurry, was used as the polishing slurry. The removal rate was calculated by measuring the wafer thickness before and after polishing using standard polarized light analysis wafer measurement methods. The wafers were polished for 60 seconds, then washed and dried before measurement. The removal rate data is presented in FIG. 7. These data show that a pad having a plurality of cylindrical protrusions with an outer perimeter of 6.28 mm, a cavity size of 1 mm in diameter, and four openings (having an opening height of 0.2 mm and an angle of 22.5 degrees) at any height provides an improved removal rate response compared to a pad having solid cylindrical protrusions of the same outer perimeter and similar number and spacing of materials.

[0042] Method The polishing pads disclosed herein can be used to polish a substrate. For example, the polishing method can include providing a substrate to be polished and then polishing using the pad disclosed herein having protrusions that contact the substrate to be polished. The substrate can be any substrate for which polishing or planarization is desired. Examples of such substrates include magnetic, optical, and semiconductor substrates. The method can be part of a substrate process or a wiring process treatment for an integrated circuit. For example, this process can be used to remove undesirable surface topography and surface defects (such as rough surfaces, agglomerated substances, lattice damage, scratches, and contamination layers or substances). In addition, in a damascene process, material is deposited to fill recessed regions created by one or more of photolithography, patterned etching, and metallization steps. Some of these steps can be inaccurate - for example, the recesses can be overfilled. The method disclosed herein can be used to remove material outside the recesses. This process can be chemical mechanical planarization or chemical mechanical polishing, both of which can be referred to as CMP. A carrier can hold a substrate to be polished - for example, a semiconductor wafer (with or without layers formed by lithography and metallization) in contact with the polishing element of the polishing pad. A slurry or other polishing medium can be dispensed into the gap between the substrate and the polishing pad. The polishing pad and the substrate can be moved relative to each other, for example, rotated. The polishing pad is typically positioned below the substrate to be polished. The polishing pad can be rotated. The substrate to be polished can also be moved, for example, along a polishing track such as an annular shape. The relative movement brings the polishing pad into proximity to and contact with the surface of the substrate.

[0043] For example, the method may include providing a chemical mechanical polishing apparatus having a platen or a carrier assembly; providing at least one substrate to be polished; providing a chemical mechanical polishing pad as disclosed herein; mounting the chemical mechanical polishing pad on the platen; optionally, providing a polishing medium (e.g., slurry and / or abrasive-free reactive liquid composition) at the interface between the polishing portion of the chemical mechanical polishing pad and the substrate; creating a dynamic contact between the polishing portion of the polishing pad and the substrate, where at least some material is removed from the substrate. The carrier assembly may provide an adjustable pressure between the substrate being polished (e.g., a wafer) and the polishing pad. The polishing medium may be dispensed onto the polishing pad and drawn into the gap between the wafer and the polishing layer. The polishing medium may include water, a pH adjuster, and optionally, without limitation, one or more of the following: abrasive grains, oxidizing agents, inhibitors, biocides, soluble polymers, and salts. The abrasive grains may be oxides, metals, ceramics, or other suitable hard materials. Typical abrasive grains are colloidal silica, fumed silica, ceria, and alumina. The polishing pad and the substrate may rotate relative to each other. When the polishing pad rotates under the substrate, the substrate may typically sweep an annular polishing track, or a polishing section, where the surface of the wafer faces directly the polishing portion of the polishing pad. The wafer surface is polished and planarized by the chemical and mechanical action of the polishing layer and the polishing medium on the surface. Optionally, the polishing surface of the polishing pad may be conditioned using a polishing conditioner before starting the polishing. Optionally, in the method of the present invention, the provided chemical mechanical polishing apparatus further includes a light source and an optical sensor (preferably a multi-sensor spectral graph); and the provided chemical mechanical polishing pad further includes an endpoint detection window; and the method further includes determining the polishing endpoint by analyzing the light reflected from the surface of the substrate that has passed back through the endpoint detection window, which transmits light from the light source through the endpoint detection window and projects it onto the optical sensor. The substrate may have a metallic or metallized surface, such as one containing copper or tungsten.The substrate can be a magnetic substrate, an optical substrate, or a semiconductor substrate.

[0044] The present disclosure further includes the following aspects.

[0045] Aspect 1: A polishing pad useful in chemical mechanical polishing, including a base pad having an upper surface and a plurality of protruding structures on the upper surface of the base pad, wherein each of the protruding structures has a body, and here, the body has: (i) an outer peripheral surface defining the outer shape of the protruding structure, (ii) an inner surface defining one or more central cavities, and (iii) an upper surface defining an initial polishing surface area, and here, the body further has an opening from the cavity to the outer peripheral surface therein, the polishing pad.

[0046] Aspect 2: The polishing pad of Aspect 1, wherein the outer shape is cylindrical, elliptical, polygonal, or an irregular curved surface.

[0047] Aspect 3: The polishing pad of any one of Aspects 1 to 2, wherein the central cavity has a cylindrical, elliptical, polygonal, or irregular curved surface shape.

[0048] Aspect 4: The polishing pad of any one of Aspects 1 to 3, including two or more cavities.

[0049] Aspect 5: The polishing pad of Aspect 4, wherein two or more cavities are defined by the inner surface and one or more separating walls or ribs.

[0050] Aspect 6: The polishing pad of any one of Aspects 1 to 3, having one cavity.

[0051] Aspect 7: The polishing pad of any one of Aspects 1 to 6, wherein each opening has a height of at least 5%, preferably at least 10%, more preferably at least 20%, and most preferably at least 30% of the height of the protruding structure.

[0052] Aspect 8: Each of the openings has a height of 80% or less, preferably 70% or less, more preferably 60% or less, even more preferably 50% or less, and most preferably 40% or less of the height of the protruding structure, and is any one of the polishing pads of Aspects 1 to 7.

[0053] Aspect 9: The number of openings at a given height in the z direction from the surface of the base pad is 2 to 80, preferably 3 to 60, more preferably 4 to 50, and most preferably 5 to 50, and is any one of the polishing pads of Aspects 1 to 8.

[0054] Aspect 10: Having a total porosity within the range of 0.3 to 0.96, preferably 0.4 to 0.95, more preferably 0.5 to 0.90, and is any one of the polishing pads of Aspects 1 to 9.

[0055] Aspect 11: The base pad and the protruding structure are integrally formed with each other, and is any one of the polishing pads of Aspects 1 to 10.

[0056] Aspect 12: The upper surface of the protruding structure wears down during the polishing of the substrate, and exposes a new polishing surface having a subsequent polishing surface area of the protruding structure that is less than 25%, preferably less than 10%, more preferably less than 5% different from the initial polishing surface area of the protruding structure, and is any one of the polishing pads of Aspects 1 to 11.

[0057] Aspect 13: The protruding structures together have a total initial polishing surface area that is the sum of the initial polishing surface areas of all the protruding structures on the pad, and during polishing, a new total polishing surface area that is less than 25%, preferably less than 10% different from the total initial polishing surface area is exposed, and is any one of the polishing pads of Aspects 1 to 12.

[0058] Aspect 14: Each protruding structure has a maximum dimension in a direction parallel to the surface of the base pad of 0.2 to 10 mm, preferably 0.5 to 5 mm, more preferably 0.7 to 2 mm, and is any one of the polishing pads of Aspects 1 to 13.

[0059] Aspect 15: The outer peripheral surface of the protruding structure is at a distance of 0.02 to 40 mm, preferably 0.05 to 20 mm, more preferably 0.1 to 10 mm, and even more preferably 0.5 to 5 mm from the outer peripheral surface of the adjacent protruding structure, and is a polishing pad according to any one of Aspects 1 to 14.

[0060] Aspect 16: The height of the protruding structure is 0.05 to 3 mm, preferably 0.1 to 2 mm, more preferably 0.5 to 1.5 mm, and is a polishing pad according to any one of Aspects 1 to 15.

[0061] Aspect 17: The distance from the outer periphery to the cavity is 0.05 to 8 mm, preferably 0.1 to 7 mm, more preferably 0.3 to 6 mm, even more preferably 0.5 to 5 mm, still more preferably 0.7 to 4 mm, even more preferably 1 to 3 mm, and most preferably 0.8 to 2 mm, and is a polishing pad according to any one of Aspects 1 to 16.

[0062] Aspect 18: The effective compression rate is 1 to 700 MPa, preferably 5 to 500 MPa, more preferably 10 to 300 MPa, and is a polishing pad according to any one of Aspects 1 to 17.

[0063] Aspect 19: The protruding structure is made of a material having 2 MPa to 10 GPa, preferably 10 MPa to 5 GPa, more preferably 50 to 900 MPa, and even more preferably 100 to 700 MPa, and is a polishing pad according to any one of Aspects 1 to 18.

[0064] Aspect 20: The effective compression rate is 1 to 90% of the effective compression model of a pad having the same material and the same external dimensions but having no cavities and openings and having the same number and the same pattern of protruding structures, preferably 5 to 90%, more preferably 10 to 80%, and even more preferably 25 to 70%, and is a polishing pad according to any one of Aspects 1 to 19.

[0065] Aspect 21: The abrasive pad according to any one of Aspects 1 to 20, wherein the cavity has a dimension in a direction parallel to the surface of the base pad that is 20 to 90%, preferably 20 to 80%, more preferably 30 to 70% of the maximum dimension of the protruding structure in a direction parallel to the surface of the base pad.

[0066] Aspect 22: A method comprising providing a substrate and polishing the substrate using the abrasive pad according to any one of Aspects 1 to 21.

[0067] Aspect 23: A method comprising providing an abrasive medium at the interface between the substrate and the abrasive pad before or during polishing.

[0068] The compositions, methods, and articles may alternatively comprise, consist of, or consist essentially of any suitable materials, steps, or components disclosed herein. The compositions, methods, and articles may be devised to lack, or substantially not include, any materials (or types), steps, or components that are not necessary in another way for the achievement of the functions or purposes of the compositions, methods, and articles.

[0069] All ranges disclosed in this specification include the endpoints, and the endpoints can be combined independently of each other (e.g., the range "up to 25 wt.%, or more specifically 5 wt.% to 20 wt.%" includes the endpoints and all intermediate values of the range "5 wt.% to 25 wt.%", etc.). Further, the specified upper and lower limits can be combined to form a range (e.g., "at least 1 weight percent or at least 2 weight percent" and "up to 10 weight percent or up to 5 weight percent" can be combined as the range "1 to 10 weight percent", or "1 to 5 weight percent" or "2 to 10 weight percent" or "2 to 5 weight percent"). "Combination" includes blends, mixtures, alloys, reaction products, etc. The terms "first", "second", etc. do not indicate any order, amount, or importance, but rather are used to distinguish one element from another. The terms "a", "an", and "the" do not indicate a limitation of number and should be construed to include both singular and plural unless specifically stated otherwise herein or clearly contradicted by the context. "Or" means "and / or" unless specifically stated otherwise. References throughout the specification to "some embodiments", "embodiments", etc. mean that the elements described in connection with those embodiments are included in at least one embodiment described herein and may or may not be present in other embodiments. Additionally, it should be understood that the described elements may be combined in any suitable manner in various embodiments. "Their combinations" are open and include any combination that includes at least one of the recited components or characteristics, optionally together with other similar or equivalent components or characteristics that may not be recited.

[0070] Unless otherwise specified herein, all test criteria are the latest criteria implemented as of the filing date of this application or, if priority is claimed, as of the filing date of the earliest priority application in which the test criteria are published.

Claims

1. A base pad having an upper surface, A plurality of discrete protruding structures on the upper surface of the base pad, each of the protruding structures having a body, where the body has (i) an outer peripheral surface defining the outer shape of the protruding structure, (ii) an inner surface defining a central cavity, and (iii) an upper surface defining an initial polishing surface area, where the body further has a wall opening in it from the central cavity to the outer peripheral surface, the dimensions of the wall opening of the outer peripheral surface being larger than the dimensions of the opening of the central cavity, the wall openings being offset from each other in the vertical and horizontal directions, the vertical direction being in the z direction with respect to the surface of the base pad, the surface of the base pad being in the x-y plane of the horizontal direction, the protruding structure having a deflection smaller than that of a solid cylindrical structure of the same initial polishing surface area, the solid cylinder having a corresponding diameter D, where D = 2 * [square root of {(initial polishing surface area) / π}], the solid cylinder having the same material as the protruding structure, a polishing pad useful in chemical mechanical polishing including a plurality of discrete protruding structures.

2. The polishing pad according to claim 1, wherein the base pad and the protruding structure are integral with each other.

3. The polishing pad according to claim 1, wherein the Young's modulus of the protruding structure is higher than the Young's modulus of the base pad.

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