Retaining ring-free chemical mechanical polishing (CMP) process

Abstract

An exemplary carrier head for a chemical mechanical polishing device may include a carrier body. The carrier head may include a flexible diaphragm coupled with the carrier body. The flexible diaphragm may include a substrate receiving surface facing away from the carrier body. The substrate receiving surface may include a plurality of gripping elements protruding away from the substrate receiving surface. A maximum lateral dimension of each of the plurality of gripping elements may be no greater than 2 millimeters.

Description

Technical Field

[0001] This application claims benefits and priority to U.S. Patent Application No. 18 / 483,973, filed October 10, 2023, entitled “RETAINING-RING-LESS CMPPROCESS”, the entire contents of which are incorporated herein by reference.

[0002] This technology relates to semiconductor systems, processes, and devices. More specifically, this technology relates to polished films deposited on substrates. Background Technology

[0003] Integrated circuits are typically formed on a substrate by sequentially depositing conductive layers, semiconductor layers, and / or insulating layers on a silicon wafer. Various manufacturing processes planarize the layers on the substrate between processing steps. For example, in some applications, such as polishing metal layers to form vias, plugs, and / or lines in trenches of patterned layers, the overlay is planarized until the top surface of the patterned layer is exposed. In other applications, such as planarization of dielectric layers for lithography, the overlay is polished until the desired thickness is maintained on the underlying layers.

[0004] Chemical mechanical polishing (CMP) is a common planarization method. This planarization method typically requires mounting the substrate on a carrier or polishing head. The exposed surface of the substrate is usually placed on a rotating polishing pad. The carrier head applies a controlled load to the substrate, pushing it toward the polishing pad. An abrasive polishing slurry is typically applied to the surface of the polishing pad.

[0005] One issue with CMP is achieving uniform polishing across the entire surface of the substrate. Typically, due to the design of CMP systems, the polishing rate may be higher or lower in areas where the polishing pad is near the substrate edges, particularly near the leading and / or trailing edges. For example, as the substrate and polishing pad move relative to each other, the trailing edge of the substrate may come into contact with the inner retaining ring, potentially creating lateral loads on the substrate. These lateral loads may concentrate at the contact point at the trailing edge, which can result in higher polishing rates there. Consequently, film thickness may be non-uniform in one or more edge regions of the substrate. This film non-uniformity can cause problems in lithography and may lead to a decrease in the grain yield of a given substrate.

[0006] Therefore, there is a need to improve systems and methods for polishing substrates to produce a uniform film across the entire surface area of ​​the substrate. This technology meets these and other needs. Summary of the Invention

[0007] An exemplary carrier head for a chemical mechanical polishing apparatus may include a carrier body. The carrier head may include a flexible diaphragm coupled to the carrier body. The flexible diaphragm may include a substrate receiving surface facing away from the carrier body. The substrate receiving surface may include a plurality of gripping elements protruding away from the substrate receiving surface. The maximum lateral dimension of each of the plurality of gripping elements may not exceed 2 mm.

[0008] In some embodiments, each of the plurality of gripping elements may include a wide base that tapers toward a gripping surface. The gripping surface may be convex or concave. Each of the plurality of gripping elements may be generally mushroom-shaped. The carrier head may include a plurality of substrate holding members coupled to a carrier body. Each of the plurality of substrate holding members may be arranged at different angular positions around the periphery of the substrate receiving surface. The plurality of holding members may collectively extend less than approximately 20% of the periphery of the substrate receiving surface. An adhesive may be applied to the gripping surfaces of at least some of the plurality of gripping elements. Each of the plurality of gripping elements may have a maximum lateral dimension not exceeding 0.1 mm. Each of the plurality of gripping elements may be flexible in the lateral direction.

[0009] Some specific embodiments of this technology may include a flexible diaphragm for a chemical mechanical polishing apparatus. The flexible diaphragm may include a flexible diaphragm body having a substrate receiving surface. The substrate receiving surface may include a plurality of gripping elements protruding away from the substrate receiving surface. The maximum lateral dimension of each of the plurality of gripping elements may not exceed 2 mm.

[0010] In some embodiments, each of the plurality of gripping elements may include a wide base that tapers towards the gripping surface. The gripping surface may be convex or concave. The height of each of the plurality of gripping elements may not exceed 1 mm. The open area of ​​the substrate receiving surface may be less than 50%.

[0011] Some specific embodiments of this technology may include methods for polishing a substrate. These methods may include engaging a plurality of gripping elements on a substrate receiving surface of a flexible diaphragm of a carrier head. These methods may include flowing polishing slurry from a slurry source to a polishing pad. The methods may include moving the carrier head to polish the substrate on top of the polishing pad.

[0012] In some embodiments, the moving carrier head may include one or both steps of rotating the carrier head and laterally translating the carrier head relative to the polishing pad. The carrier head may include a plurality of substrate holding members arranged at different angular positions around the periphery of the substrate receiving surface. Each of the plurality of substrate holding members may include an inner portion that contacts the outer periphery of the substrate and terminates before reaching the polishing pad, and an outer region that contacts the polishing pad.

[0013] Compared to conventional systems and techniques, this type of technology offers numerous advantages. For example, the polishing head described herein helps prevent over-polishing in the edge regions of the substrate, particularly the trailing edge, during the polishing operation. This improves the uniformity of film thickness across the entire substrate surface, thereby increasing grain yield. These and other specific embodiments, along with their many advantages and features, will be described in more detail below in conjunction with the accompanying drawings. Attached Figure Description

[0014] The nature and advantages of the disclosed technology can be further understood by referring to the remainder of the specification and the accompanying drawings.

[0015] Figure 1 A schematic cross-sectional view of an exemplary polishing system according to some specific embodiments of the present technology is shown.

[0016] Figure 2 A schematic regional cross-sectional view of an exemplary carrier head according to some specific embodiments of the present technology is shown.

[0017] Figure 3 This diagram shows a regionally equidistant schematic of an exemplary flexible diaphragm according to some specific embodiments of the present technology.

[0018] Figure 3 A shows Figure 3 A schematic diagram of the equidistant regional cross-section of a substrate receiving surface of a flexible diaphragm.

[0019] Figure 4A A schematic side view of a cross-section of an exemplary gripping element according to some specific embodiments of the present technology is shown.

[0020] Figure 4B A schematic side view of a cross-section of an exemplary gripping element according to some specific embodiments of the present technology is shown.

[0021] Figure 4C A schematic side view of a cross-section of an exemplary gripping element according to some specific embodiments of the present technology is shown.

[0022] Figure 5 A regional schematic top plan view of an exemplary carrier head according to some specific embodiments of the present technology is shown.

[0023] Figure 5A Showing Figure 5 A schematic cross-sectional side view of the retaining member of the bearing head in the middle.

[0024] Figure 5B It shows Figure 5 A schematic cross-sectional side view of the bearing head retaining member.

[0025] Figure 6 This is a flowchart of an exemplary method for polishing a substrate according to some specific embodiments of the present technology.

[0026] Several of the illustrations are schematic. It should be understood that these illustrations are for reference only and should not be considered to be drawn to scale unless specifically stated otherwise. Furthermore, as illustrative, these illustrations are provided to aid understanding and may not include all aspects or information compared to realistic representations, and may include exaggerated material for illustrative purposes.

[0027] In the accompanying drawings, similar parts and / or features may have the same reference numerals. Furthermore, various parts of the same type may be distinguished by adding a letter after the reference numeral to differentiate them. If only the first reference numeral is used in the description, the description applies to any similar part having the same first reference numeral, regardless of the letter used. Detailed Implementation

[0028] In conventional chemical mechanical polishing (CMP) operations, it is often difficult to achieve uniform polishing of the substrate surface. Traditional CMP polishing involves placing the substrate face down on a polishing pad and securing it to a rotating pad using a carrier. As the substrate and polishing pad move relative to each other, the trailing edge of the substrate may be pushed against the inner surface of the inner retaining ring. In conventional CMP systems, this contact between the inner retaining ring and the substrate trailing edge creates a lateral load, increasing stress on the substrate near the trailing edge. This increased substrate stress relative to other parts of the substrate leads to increased polishing / material removal rates at and / or near the trailing edge. This can result in film inhomogeneity issues, thus reducing grain yield. Furthermore, the use of a retaining ring can cause slurry to accumulate on the inner surface of the retaining ring instead of reaching the substrate surface being polished, potentially leading to uneven polishing and / or slurry waste.

[0029] This technology overcomes the problems of traditional polishing systems by using a diaphragm that adheres to or otherwise holds the substrate instead of a retaining ring. The diaphragm may include several small gripping elements that increase the surface contact between the substrate and the diaphragm, thereby reducing or eliminating the need for a retaining ring. For example, several small retaining rings can be used instead of a retaining ring, positioned at different angular locations around the edge of the substrate. These holding members reduce the contact area with the substrate and reduce or eliminate any pad deformation effects caused by the use of a retaining ring. Furthermore, eliminating the retaining ring helps prevent slurry agglomeration, thus reducing slurry usage. These technologies can be used in conjunction with conventional CMP systems to produce substrates with better film thickness uniformity.

[0030] While the remainder of this disclosure routinely identifies specific film polishing processes utilizing the disclosed technology, it is readily understood that these systems and methods are equally applicable to a wide variety of other semiconductor processing operations and systems. Therefore, the technology should not be considered limited to the polishing systems or processes described herein. Before describing systems and methods or operations with exemplary process sequences according to some specific embodiments of the present technology, this disclosure will discuss one possible system that can be used with the present technology. It should be understood that the present technology is not limited to the described apparatus, and the discussed processes can be performed in any number of processing chambers and systems, with any number of modifications possible, some of which will be noted below.

[0031] Figure 1 A schematic cross-sectional view of an example polishing system 100 according to some specific embodiments of the present technology is shown. The polishing system 100 includes a platform assembly 102, which includes a lower platform 104 and an upper platform 106. The lower platform 104 may define an internal volume or cavity through which connections can be made, and may include endpoint detection devices or other sensors or devices, such as eddy current sensors, optical devices, or other components for monitoring polishing operations or parts. For example, as further described below, a fluid coupling may form a conduit extending through the lower platform 104 and may access the upper platform 106 through the back side of the upper platform. The platform assembly 102 may include a polishing pad 110 mounted on a first surface of the upper platform. A substrate carrier 108 or carrier head may be disposed above and facing the polishing pad 110. The platform assembly 102 is rotatable about axis A, while the substrate carrier 108 is rotatable about axis B. The substrate carrier can also be configured to sweep back and forth along the platform assembly from the inner radius to the outer radius, which can reduce uneven wear on the surface of the polishing pad 110 to some extent. The polishing system 100 may also include a fluid delivery arm 118 located above the polishing pad 110 for delivering polishing fluid (such as polishing slurry) onto the polishing pad 110. In addition, the pad adjustment assembly 120 may be disposed above the polishing pad 110 and may face the polishing pad 110.

[0032] In some specific embodiments of the chemical mechanical polishing process, a rotating and / or sweeping substrate carrier 108, shown in dashed lines, can apply a downward force to a substrate 112, which may be disposed within or coupled to the substrate carrier. As the polishing pad 110 rotates about the central axis of the platform assembly, the applied downward force can press the material surface of the substrate 112 against the polishing pad 110. The interaction between the substrate 112 and the polishing pad 110 can occur in the presence of one or more polishing slurries delivered by the fluid delivery arm 118. Typical polishing slurries may comprise slurries formed from aqueous solutions, in which suspended abrasive particles may be present. Typically, polishing slurries contain pH adjusters and other chemically active ingredients, such as oxidants, to achieve chemical mechanical polishing of the material surface of the substrate 112.

[0033] The pad adjustment assembly 120 is operable to attach a fixed grinding adjustment disc 122 to the surface of the polishing pad 110, which can be rotated as previously described. The adjustment disc can be used to operate the polishing pad before, after, or during the polishing of the substrate 112. Adjusting the polishing pad 110 with the adjustment disc 122 can revitalize the polished surface of the polishing pad 110 through grinding and remove polishing byproducts and other debris, thereby maintaining the polishing pad 110 in the desired state. The upper platform 106 can be disposed on the mounting surface of the lower platform 104 and can be coupled to the lower platform 104 using multiple fasteners 138, such as an annular flange extending through the lower platform 104.

[0034] The polishing platform assembly 102 (and the upper platform 106) is sized to fit any desired polishing system and can be used with substrates of any diameter, including 200 mm, 300 mm, 450 mm, or larger. For example, a polishing platform assembly configured for polishing a 300 mm diameter substrate may be characterized by a diameter greater than about 300 mm, such as between about 500 mm and about 1000 mm, or greater than about 500 mm. The diameter of the platform can be adjusted to accommodate substrates characterized by larger or smaller diameters, or, for polishing platform 106, its size may be suitable for polishing multiple substrates simultaneously. The thickness of the upper platform 106 may be between about 20 mm and about 150 mm, and may be characterized by a thickness less than or about 100 mm, such as less than or about 80 mm, less than or about 60 mm, less than or about 40 mm, or smaller. In some specific embodiments, the diameter-to-thickness ratio of the polishing platform 106 may be greater than or about 3:1, greater than or about 5:1, greater than or about 10:1, greater than or about 15:1, greater than or about 20:1, greater than or about 25:1, greater than or about 30:1, greater than or about 40:1, greater than or about 50:1, or more.

[0035] The upper and / or lower platforms may be formed of a suitable, hard, lightweight material resistant to the corrosive agents of the polishing slurry, such as aluminum, aluminum alloys, or stainless steel, and of course, any number of materials may be used. The polishing pad 110 may be formed of any number of materials, including polymeric materials such as polyurethane, polycarbonate, fluoropolymers, polytetrafluoroethylene polyphenylene sulfide, or any combination of these or other materials. Additional materials may be or include open-cell or closed-cell foamed polymers, synthetic rubber, felt, impregnated felt, plastics, or any other material that may be compatible with the processing chemicals. It should be understood that the inclusion of polishing system 100 is intended to provide appropriate reference to the components discussed below, which may be incorporated into system 100. Although the description of polishing system 100 is not intended to limit the technology in any way, specific embodiments of the technology may be incorporated into any number of polishing systems that may benefit from the components and / or functions further described below.

[0036] Figure 2 A schematic cross-sectional side view of an example carrier head 200 according to some specific embodiments of the present technology is shown. The carrier head 200 can show a regional view of the components under discussion, which can be integrated into a polishing system, similar to polishing system 100. The carrier head 200 can be used as a substrate carrier 108 in some specific embodiments. The carrier head 200 may include a housing 202, a base assembly 204 (the housing 202 and the base assembly 204 may be referred to as the carrier body), a universal joint mechanism 206 (which can be regarded as part of the base assembly 204), a loading chamber 208, an inner ring assembly including an inner ring 240 and a first flexible diaphragm 270, an outer ring 260 and a substrate backing assembly 210, the substrate backing assembly 210 may include a second flexible diaphragm 250, the shape of the first flexible diaphragm 270 providing an annular chamber 272, and the second flexible diaphragm 250 defining a plurality of pressurizable chambers.

[0037] The housing 202 may be generally circular and may be connected to a drive shaft to rotate with it during polishing. A channel (not shown) may extend through the housing 202 for pneumatic control of the carrier head 200. The base assembly 204 may be a vertically movable assembly located below the housing 202. A universal joint mechanism 206 may allow the base assembly 204 to perform universal joint movement relative to the housing 202 while preventing lateral movement of the base assembly 204 relative to the housing 202. A loading chamber 208 may be located between the housing 202 and the base assembly 204 to apply a load, i.e., downward pressure or weight, to the base assembly 204. The vertical position of the base assembly 204 relative to the polishing pad (such as polishing pad 110) may also be controlled by the loading chamber 208. The substrate backing assembly 210 may include a flexible diaphragm 250, the lower surface 252 of which may provide a mounting surface for the substrate 280.

[0038] The substrate 280 may be secured by an inner ring assembly, which may be clamped onto the base assembly 204. The inner ring assembly may consist of an inner ring 240 and a flexible diaphragm 250, its shape providing an annular chamber. The inner ring 240 may be positioned below and configured to be secured to the flexible diaphragm 250. While the inner ring 240 may be configured to secure the substrate 280 and provide active edge process control, the outer ring 260 may provide positioning or reference for the bearing head 200 to the surface of the polishing pad. Furthermore, the outer ring 260 may contact the inner ring 240 and provide lateral reference. The outer ring 260 may circumferentially surround the inner ring 240 and may include an inner surface abutting against the outer surface of the inner ring 240. Like the inner ring 240, the lower surface of the outer ring 260 may contact the polishing pad. The lower surface of the outer ring 260 may be a smooth, abrasion-resistant surface and may be selected as a surface that does not abrade the polishing pad. The upper surface of the outer ring 260 may be fixed to the base 204; for example, the outer ring 260 may not be vertically movable relative to the base 204. In some embodiments, the upper portion of the outer ring 260 may be formed of a material that is harder than the lower portion of the outer ring 260. For example, the lower portion may be a plastic, such as polyetheretherketone (PEEK), carbon-filled PEEK, Teflon®-filled PEEK, polyamide-imide (PAI), or a composite material, while the upper portion may be a metal, such as stainless steel, molybdenum, or aluminum, or a ceramic, such as alumina. The portion of the outer ring 260 including the lower surface may be formed of a material that is harder than the portion of the inner ring 240 including the second surface 246. This may result in a lower wear rate for the outer ring 260 compared to the inner ring 240. For example, the lower portion of the outer ring 260 may be a plastic with a higher hardness than the plastic of the inner ring 240.

[0039] The flexible diaphragm 250 can be configured to be clamped to the base assembly 204 from above and fixed to the inner ring 240 from below. Positioning the flexible diaphragm between the inner ring 240 and the carrier head 200 reduces or eliminates the effect of carrier deformation on the inner ring 240, which occurs when the ring 240 is directly fixed to the carrier head 200. Eliminating this carrier deformation reduces uneven wear on the inner ring 240, lowers processing variability at the substrate edges, allows for the use of lower polishing pressure, and extends the ring's lifespan. The flexible diaphragm 250 can be formed of a resilient material, allowing the diaphragm to bend under pressure. Resilient materials may include silicone and other example materials.

[0040] Figure 3 A regional schematic elevation view of an example flexible diaphragm 300 according to some specific embodiments of the present technology is shown. The diaphragm 300 can be used to perform substrate polishing operations. Figure 3A regional view of the components under discussion may be displayed, which may be incorporated into the chemical mechanical polishing system described herein, such as polishing system 100. Diaphragm 300 may be used as a flexible diaphragm 250 and may be used in carrier heads, such as carrier head 108 and / or carrier head 200, in some embodiments. Diaphragm 300 may be understood to include any features described for diaphragm 250. Diaphragm 300 may be used to grip or otherwise secure a substrate to a carrier head during polishing operations. Diaphragm 300 may include a diaphragm body 305, characterized by a first surface 310 (e.g., an upper surface) facing the carrier body and a second surface 315 (e.g., a lower surface) opposite the first surface 310. Diaphragm body 305 may be formed of a resilient material, allowing diaphragm body 305 to bend under pressure. Resilient materials may include rubber, silicone, polyurethane, polysiloxane, and other example materials such as polymeric materials. In some embodiments, diaphragm body 305 may be disc-shaped, for example having a circular or elliptical outer periphery.

[0041] The second surface 315 may form or define the substrate receiving surface 320, the size and shape of which may contact the back side of the substrate. For example... Figure 3In the best illustration of A, the substrate receiving surface 320 may define a plurality of gripping elements 325 protruding from the substrate receiving surface 320. The gripping elements 325 may include microhairs, microstructures, and / or other small, unique structures. Each gripping element 325 may be laterally flexible and may include a gripping surface 330 positioned to contact the back side of the substrate. As shown, each gripping surface 330 may be generally circular, although other shapes may be used in various embodiments. The gripping elements 325 may be distributed uniformly or non-uniformly around the substrate receiving surface 320. For example, as shown, adjacent gripping elements 325 are separated by gaps 335, and the gripping elements 325 are distributed at intervals to form a grid across the substrate receiving surface 320. The gripping elements 325 may be arranged in one or more columns, rows, rings, and / or other arrays. As shown in the figure, gripping elements 325 are arranged in several columns and rows, with the gripping elements 325 in adjacent columns and rows staggered, such that the central axis of the gripping element 325 in one column / row is aligned with the center of the gap 335 in the adjacent column / row. It is understood that this staggered arrangement of gripping elements 325 is merely an example, and many variations exist. In some specific embodiments, the open area of ​​the substrate receiving surface 320 (e.g., the area occupied by the gap 335) may be no greater than 50%, no greater than 45%, no greater than 40%, no greater than 35%, no greater than 30%, no greater than 25%, no greater than 20%, no greater than 15%, no greater than 10%, no greater than 5%, or less, while the remaining area of ​​the substrate receiving surface 320 is occupied by the gripping surfaces 330 of the gripping elements 325. The substrate receiving surface 320 may include any number of gripping elements 325. For example, the substrate receiving surface 320 may include at least 100 gripping elements, at least 200 gripping elements, at least 300 gripping elements, at least 400 gripping elements, at least 500 gripping elements, at least 1000 gripping elements, at least 5000 gripping elements, at least 10000 gripping elements, or more.

[0042] Each gripping element 325 may have a height (e.g., protrusion distance) substantially the same as the main surface of the substrate receiving surface 320 (e.g., with a deviation of less than 10%, less than 5%, less than 3%, less than 1%, or less). For example, each gripping element 325 may have a height not greater than 1 mm, not greater than 0.75 mm, not greater than 0.5 mm, not greater than 0.25 mm, not greater than 0.1 mm, not greater than 0.075 mm, not greater than 0.05 mm, not greater than 0.025 mm, not greater than 0.015 mm, or less. For example, the maximum height of each gripping element 325 may be between 0.015 mm and 1 mm. In some embodiments, the gripping elements 325 and / or gripping surfaces 330 may all have the same lateral dimensions and shape, while in other embodiments, some or all of the gripping elements 325 and / or gripping surfaces 330 may have different lateral shapes and / or dimensions. The maximum lateral dimension (e.g., diameter) of each gripping element 325 and / or gripping surface 330 shall not exceed 2 mm, 1.75 mm, 1.5 mm, 1.25 mm, 1 mm, 0.75 mm, 0.5 mm, 0.25 mm, 0.1 mm, 0.075 mm, 0.05 mm, 0.025 mm, 0.01 mm, or 0.005 mm or less. For example, the maximum lateral dimension of each gripping element 325 may be between 0.005 mm and 2 mm.

[0043] The gripping element 325 can be formed on the substrate receiving surface 320 using various techniques. For example, in some embodiments, the gripping element 325 can be microprinted and / or micromolded onto the substrate receiving surface 320. The gripping element 325 can be formed of the same or different material as the rest of the diaphragm body 305. For example, the gripping element 325 can be formed of rubber, silicone, and / or other elastomers and / or polymeric materials. In some embodiments, some or all of the gripping surface 330 can be formed and / or coated with adhesives and / or high-friction materials to better enhance the ability of each gripping surface 330 to grip the back side of the substrate. Suitable materials may include, but are not limited to, polymeric materials.

[0044] Figures 4A-4CThe illustration shows a cross-sectional side view of a gripping element 400 according to some specific embodiments of the present technology. The gripping element 400 may be disposed on a substrate receiving surface of a flexible diaphragm, such as flexible diaphragm 250 or flexible diaphragm 300. The gripping element 400 may serve as a gripping element 325 and may include any features associated with gripping element 325. Each gripping element 400 may include a base 405 at a first (e.g., bottom) end and a gripping surface 410 at a second (e.g., top) end. A rod 415 may extend between and couple to a base 405 and a gripping surface 410. In some embodiments, the base 405 may be wider than the rod 415, such that the gripping element 400 tapers from the wide base 405 to the gripping surface 310. The degree of taper may be constant along the length of the rod 415, such as... Figure 4A In the rod portion 415a, in other embodiments, the degree of taper can be variable (e.g., bending) along the length direction of the rod portion 415. Figure 4B The lever portion 415b is used in the gripping element 400. The use of a wider base and a narrower lever portion 415 (e.g., with a degree of taper) provides strength to the gripping element 400 while also providing a degree of lateral flexibility, helping the gripping element 400 maintain contact with the substrate when the substrate is subjected to lateral and / or rotational forces during polishing operations. In some embodiments, the base 405 and the lever portion 415 may have the same constant cross-section, for example... Figure 4C The rod part is 415c.

[0045] In some embodiments, the gripping surface 410 may be wider than the lever portion 415. In such embodiments, the transition between the lever portion 415 and the gripping surface 410 can take different forms. For example, as... Figure 4A As shown, the transition between the rod portion 415a and the gripping surface 410a can have a variable (e.g., curved) taper. Figure 4B As shown, the transition between the rod portion 415b and the gripping surface 410b can have a variable (e.g., curved) taper. Figure 4CAs shown, the transition between the lever 415c and the gripping surface 410c can be stepped. In some embodiments, the width of the base 405 can be the same as or different from the width of the gripping surface 410. For example, in various embodiments, the base 405 can be wider or narrower than the gripping surface 410. Because the width of the lever 415 and / or the base 405 is smaller than the width of the gripping surface 410, the gripping element 400 can be generally mushroom-shaped. In embodiments where the base 405 is smaller than the gripping surface 410, the gap between adjacent bases 405 may be larger than the gap between adjacent gripping surfaces, which may result in the diaphragm opening area of ​​the base 405 being larger than the opening area of ​​the gripping surface 410. Similarly, in embodiments where the base 405 is larger than the gripping surface 410, the gap between adjacent bases 405 may be smaller than the gap between adjacent gripping surfaces, which may result in the diaphragm opening area at the base 405 being smaller than the diaphragm opening area at the gripping surface 410.

[0046] The gripping surface 410 can take various forms to provide different gripping characteristics. For example, such as Figure 4A As shown, the gripping surface 410a can be concave. The concave gripping surface 410a can act as a suction cup, gripping the back side of the substrate. For example, when a carrier head having a flexible diaphragm including the gripping element 400 abuts against the back side of the substrate, the center of the concave region of the gripping surface 410a can be pushed towards the back side of the substrate. This forces any air within the concave gripping surface 410a to dislodge, creating a suction effect that allows the gripping surface 410a to firmly grip the back side of the substrate. Figure 4B As shown, the gripping surface 410b can be convex. Using a convex gripping surface 410b can help increase the contact area between the back side of the substrate and the gripping surface 410b. For example, since the gripping element 400 is formed of an elastomer and / or other deformable material, the compressive force generated by the engagement of the bearing head and the substrate with the polishing pad can compress the convex gripping surface 410b against the back side of the substrate. The compression of the convex gripping surface 410b can cause the peripheral area of ​​the gripping surface 410b to be pushed towards and contact the back side of the substrate. This will effectively increase the contact area between the gripping surface 410b and the back side of the substrate, and will result in an increase in the friction and gripping force between the two components. Figure 4C As shown, the gripping surface 410c can be substantially planar, which allows all or substantially all (e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 95% or more) of the surface area of ​​the gripping surface 410c to contact the back side of the substrate. The increased contact area can help increase the friction between the flexible diaphragm and the back side of the substrate, thereby enabling the diaphragm to grip the substrate better.

[0047] Although Figures 4A-4CThree gripping elements 400 with a specific configuration are shown, but it will be understood that many variations exist. For example, in various embodiments, any arrangement of the base, levers, gripping surface size, shape, and transition type can be used. Furthermore, the planarity (e.g., convex, concave, flat) of each gripping surface can be selected through any combination of the base, levers, gripping surface size, shape, and transition type. Additionally, gripping elements with features not explicitly described herein can be utilized. In some embodiments, each gripping element on the diaphragm may have the same structure, while in other embodiments, one or more gripping elements may be different. To cite just one example, gripping elements near the peripheral edge of the substrate receiving surface may take a different form than gripping elements provided in the central region of the substrate receiving surface.

[0048] Compared to conventional planar diaphragms, using diaphragms with the gripping elements described herein improves the contact and friction / grip effect between the diaphragm and the back side of the substrate. For example, due to manufacturing limitations, the flatness of conventional planar diaphragms may be non-uniform at the microscopic level, which can limit the contact area between the diaphragm and the back side of the substrate. Using numerous small gripping elements allows each gripping element to independently contact and / or deform against the back side of the substrate, thereby increasing the actual contact area between the diaphragm and the back side of the substrate. Furthermore, the ability of individual gripping elements to bend laterally and / or longitudinally better ensures that the diaphragm with gripping elements maintains secure contact with the back side of the substrate when the substrate is subjected to lateral and / or rotational forces during polishing operations. The enhanced gripping capability of such diaphragms allows for the removal and / or reduction in the size of the retaining ring of the carrier head, as the diaphragm can have sufficient contact force to prevent the substrate from slipping off the carrier head during processing operations.

[0049] As described above, the diaphragm and gripping elements described herein can reduce or diminish the need for a retaining ring (such as inner ring 240) within the carrier head. In some embodiments, to supplement the gripping capability of the diaphragm, the carrier head may include several retaining members positioned to prevent the substrate from slipping off the substrate receiving surface during polishing operations. Figure 5 A schematic top plan view of a support head 500 is shown, which includes several retaining members 505 positioned around a flexible diaphragm 510. The support head 500 may be similar to support head 108 and / or support head 200 and may include any features associated with support head 108 and / or support head 200. The diaphragm 510 may be similar to diaphragm 300 and may include any feature descriptions associated with diaphragm 300, including gripping elements 325 and 400.

[0050] The retaining member 505 may be formed of a material compatible with the polishing slurry, and the material has abrasion-resistant properties to prevent wear from the retaining member 505 due to sliding on the polishing pad. In some embodiments, the retaining member 505 may be formed of polyetheretherketone (PEEK), carbon-filled PEEK, Teflon®-filled PEEK, polyamide-imide (PAI), or a composite material, although other materials may also be used in various embodiments. The retaining member 505 may be positioned in a radial location in the carrier head 500 similar to the inner ring, such as the inner ring 240. For example, the retaining member 505 may be positioned radially outward of the diaphragm 510 such that at least a portion of the inner surface of each retaining member 505 is aligned with the peripheral edge of the substrate receiving surface of the diaphragm 510. Such positioning allows a portion of the inner surface of each retaining member 505 to contact the peripheral edge of the substrate positioned relative to the substrate receiving surface of the diaphragm 510, helping to keep the substrate at least substantially centered relative to the substrate receiving surface of the diaphragm 510. In some embodiments, the inner surface of each retaining member 505 may be arc-shaped, for example having a radius that matches the radius of the substrate receiving surface of the diaphragm 510, in order to provide a larger contact area between each retaining member 505 and the peripheral edge of the substrate.

[0051] Any number of retaining members 505 can be used to hold the substrate in the desired position. In some embodiments, two larger retaining members can be used to collectively hold a large portion (e.g., at least 25%) of the substrate's peripheral edge. In other embodiments, a larger number of retaining members 505 can be used. For example, the carrier head 500 may include three or more retaining members, four or more retaining members, five or more retaining members, six or more retaining members, nine or more retaining members, twelve or more retaining members, fifteen or more retaining members, or more. The retaining members 505 may position the diaphragm 510 around the periphery of the substrate receiving surface at regular and / or irregular intervals. The retaining members 505 may be the same or different in size. In some embodiments, the retaining members 505 may collectively extend along a distance less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, or less than the peripheral edge of the substrate receiving surface. Using smaller retaining members 505 at discrete locations can effectively hold the substrate within the bearing head 500 (e.g., due to the greater gripping force provided by the diaphragm 510) while providing sufficiently open edges to prevent polishing slurry from agglomerating with the inner surface of the retaining member 505, as is often seen in conventional retaining rings.

[0052] Figure 5A and 5BThe illustration shows a partial cross-sectional side view of the retaining member 505. In some embodiments, the inner wall 507a of the retaining member 505a may be vertical, such that substantially all of the inner wall 507a is in contact with the peripheral edge of the substrate 550, as shown below. Figure 5A As shown. In other embodiments, the inner wall 507b of the retaining member 505b may include at least one transition such that only a portion of the inner wall 507b contacts the peripheral edge of the substrate 550. For example, the upper portion 508b of the inner wall 507b may be radially inward of the lower portion 509b of the inner wall 507b, such that the upper portion 508b contacts the peripheral edge of the substrate 550, while the lower portion 509b is laterally spaced from the peripheral edge of the substrate 550. The transition between the upper portion 508b and the lower portion 509b may be stepped and / or tapered (e.g., having a linear and / or variable taper). Such a design allows the contact area between the retaining member 505 and the polishing pad to be moved radially outward from the substrate 550 and may help reduce or eliminate uneven polishing forces that may occur due to pad deformation and / or bounce, as seen in conventional retaining rings. In addition, using small, discontinuous retaining members 505 may help reduce the effects of pad deformation and / or bounce, because only a small area around the substrate 550 will be affected by the deformation of the retaining members 505, and any residual effects will be mitigated by the rotation of the substrate 550 relative to the polishing pad.

[0053] Figure 6 Exemplary operations in a method 600 for polishing a substrate according to some specific embodiments of the present technology are shown. Method 600 can be performed using carrier heads (e.g., carrier head 108, carrier head 200, or carrier head 500) and diaphragms (e.g., diaphragm 300 and diaphragm 510) as described herein. In some specific embodiments, method 600 may include operations prior to substrate polishing. For example, prior to polishing, the substrate may undergo one or more deposition and / or etching operations, as well as any planarization or other process operations. Method 600 may include numerous operations that can be performed automatically within the system to limit human interaction and provide greater efficiency and accuracy than manual operation. Method 600 may be performed as part of or in conjunction with conventional CMP polishing processes.

[0054] Method 600 may include engaging multiple gripping elements at operation 605 with a substrate receiving surface of a flexible diaphragm of a carrier head. For example, the substrate may be positioned against the substrate receiving surface of the diaphragm and pressed against a polishing pad. Method 600 may include, at operation 610, allowing polishing slurry to flow from a slurry source to the polishing pad. The substrate may be polished on top of the polishing pad at operation 615. For example, the carrier head may rotate and / or translate (or scan) the substrate around the surface of the polishing pad, thereby gradually removing material from the substrate surface by abrasive particles within the polishing slurry in a desired pattern and / or to achieve a desired film thickness distribution. In some embodiments, the polishing pad may also rotate and / or translate in addition to or instead of rotating and / or translating the carrier head. During the polishing operation, the back side of the substrate may be positioned against the flexible diaphragm, and pressure may be applied to the back side of the substrate. The substrate may be held in the desired position relative to the carrier head and the flexible diaphragm using the gripping force (e.g., adhesion, friction, etc.) of the gripping elements and / or using a plurality of holding members radially outwardly positioned at several discrete locations on the substrate.

[0055] In the foregoing description, numerous details have been listed for illustrative purposes to enable an understanding of various specific embodiments of the present technology. However, it will be apparent to those skilled in the art that some specific embodiments may omit some of these details or employ additional details.

[0056] Having disclosed several specific embodiments, those skilled in the art will recognize that various modifications, alternative structures, and equivalents can be used without departing from the spirit of the embodiments. Furthermore, to avoid unnecessarily obscuring the technology, some well-known processes and elements have not been described. Therefore, the above description should not be considered as a limitation on the scope of the technology.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same common or conventional meaning. The articles “a” and “an” as used herein refer to one or more (i.e., at least one) grammatical objects. For example, “an element” refers to one or more elements. The terms “approximately” and / or “about” as used herein, when referring to measurable values ​​such as quantities, durations of time, include variations of ±20% or ±10%, ±5% or +0.1% compared to a specified value, as such variations are appropriate in the context of the systems, apparatuses, circuits, methods, and other specific embodiments described herein. The term “substantially” as used herein refers to measurable values ​​such as quantities, durations of time, physical properties (such as frequency), and also includes variations of ±20% or ±10%, ±5% or +0.1% compared to a specified value, as such variations are appropriate in the systems, apparatuses, circuits, methods, and other specific embodiments described herein.

[0058] Where a numerical range is provided, unless the context explicitly specifies otherwise, it should be understood that each interval value between the upper and lower limits of the range, down to the smallest unit of the lower limit, is also specifically disclosed. Any narrower range between any specified value or unspecified intermediate value within the specified range and any other specified value or intermediate value within that specified range is also included. The upper and lower limits of these narrower ranges may be independently included or excluded from the range, and each range that includes one, two, or two limits is also included in the technique, but is subject to any explicitly excluded limits within the range. When the range includes one or two limits, the range that does not include one or two limits is also included.

[0059] The singular forms “a,” “an,” and “the” used herein and in the appended claims include the plural unless the context clearly requires otherwise. Thus, for example, “heater” includes a plurality of such heaters, “protrusion” includes one or more protrusions and their equivalents known to those skilled in the art, and so on.

[0060] In addition, the terms "comprising," "including," "having," "containing," "owning," and "encompassing" are used in this specification and the following claims to indicate the presence of the stated feature, integer, component, or operation, but do not exclude the presence or additional presence of one or more other features, integers, components, operations, behaviors, or groups.

Claims

1. A support head for a chemical mechanical polishing apparatus, the support head comprising: Vehicle body; A flexible diaphragm, coupled to the carrier body, includes a substrate receiving surface facing away from the carrier body, wherein: The substrate receiving surface includes a plurality of gripping elements, the plurality of gripping elements protruding away from the substrate receiving surface; and The maximum lateral dimension of each of the plurality of gripping elements is no greater than 2 mm.

2. The support head of the chemical mechanical polishing apparatus as described in claim 1, wherein: Each of the plurality of gripping elements includes a wide base that tapers toward the gripping surface.

3. The support head of the chemical mechanical polishing apparatus as described in claim 2, wherein: The gripping surface is convex.

4. The support head of the chemical mechanical polishing apparatus as described in claim 2, wherein: The gripping surface is concave.

5. The support head of the chemical mechanical polishing apparatus as described in claim 1, wherein: Each of the plurality of gripping elements is substantially mushroom-shaped.

6. The support head of the chemical mechanical polishing apparatus as claimed in claim 1, wherein the support head further comprises: A plurality of substrate holding members are coupled to the carrier body, wherein each of the plurality of substrate holding members is disposed at a different angular position around the periphery of the substrate receiving surface.

7. The support head of the chemical mechanical polishing apparatus as described in claim 6, wherein: The plurality of retaining members extend together along approximately 20% or less of the periphery of the receiving surface of the substrate.

8. The support head of the chemical mechanical polishing apparatus as claimed in claim 1, wherein the support head further comprises: An adhesive is applied to the gripping surface of at least some of the plurality of gripping elements.

9. The support head of the chemical mechanical polishing apparatus as described in claim 1, wherein: The maximum lateral dimension of each of the plurality of gripping elements is no greater than 0.1 mm.

10. The support head of the chemical mechanical polishing apparatus as described in claim 1, wherein: Each of the plurality of gripping elements is flexible in the lateral direction.

11. A flexible diaphragm for a chemical mechanical polishing apparatus, the flexible diaphragm comprising: The flexible diaphragm body has a substrate receiving surface, wherein: The substrate receiving surface includes a plurality of gripping elements, the plurality of gripping elements protruding away from the substrate receiving surface; and The maximum lateral dimension of each of the plurality of gripping elements is no greater than 2 mm.

12. The flexible diaphragm for a chemical mechanical polishing apparatus as described in claim 11, wherein: Each of the plurality of gripping elements includes a wide base that tapers toward the gripping surface.

13. The flexible diaphragm for a chemical mechanical polishing apparatus as described in claim 12, wherein: The gripping surface is convex.

14. The flexible diaphragm for a chemical mechanical polishing apparatus as described in claim 12, wherein: The gripping surface is concave.

15. The flexible diaphragm for a chemical mechanical polishing apparatus as described in claim 11, wherein: The height of each of the plurality of gripping elements is no greater than 1 mm.

16. The flexible diaphragm for a chemical mechanical polishing apparatus as described in claim 11, wherein: The open area of ​​the receiving surface of the substrate is less than 50%.

17. A method for polishing a substrate, the method comprising: Multiple gripping elements on the substrate receiving surface of the flexible diaphragm of the carrier head are engaged to the substrate. The polishing slurry flows from the slurry source to the polishing pad; and The carrier head is moved to polish the substrate on the top of the polishing pad.

18. The method for polishing a substrate as claimed in claim 17, wherein: Moving the carrier head includes: rotating the carrier head and laterally translating the carrier head relative to the polishing pad, or both of these actions.

19. The method for polishing a substrate as described in claim 17, wherein: The carrier head includes multiple substrate holding members, which are arranged at different angular positions around the periphery of the substrate receiving surface.

20. The method for polishing a substrate as claimed in claim 17, wherein: Each of the plurality of substrate holding members includes an inner portion and an outer region, the inner portion contacting the periphery of the substrate and terminating before reaching the polishing pad, and the outer region contacting the polishing pad.

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