US20160101500A1

US20160101500A1 - Chemical mechanical polishing pad with internal channels

Info

Publication number: US20160101500A1
Application number: US14/695,778
Authority: US
Inventors: Jason Garcheung Fung; Rajeev Bajaj; Kasiraman Krishnan; Mahendra C. Orilall; Fred C. Redeker; Russell Edward Perry; Gregory E. Menk; Daniel Redfield
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2014-10-09
Filing date: 2015-04-24
Publication date: 2016-04-14
Also published as: CN106716604A; KR20170068534A; WO2016057075A1

Abstract

A polishing pad for chemical mechanical polishing is provided. The polishing pad includes a base region having a supporting surface. The polishing pad further includes a plurality of polishing features forming a polishing surface, the polishing surface opposing the supporting surface. The polishing pad further includes one or more channels formed in an interior region of the polishing pad and extending at least partly around a center of the polishing pad, wherein each channel is fluidly coupled to at least one port.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional patent application Ser. No. 62/062,092, filed Oct. 9, 2014 and U.S. Provisional Patent Application Ser. No. 62/065,193, filed on Oct. 17, 2014. Each of the aforementioned patent applications is incorporated by reference.

BACKGROUND

1. Field
Embodiments disclosed herein generally relate to the manufacture of polishing articles utilized in chemical mechanical polishing (CMP) processes. More specifically, embodiments disclosed herein relate to polishing pads utilized in CMP processes and methods of fabricating polishing pads using additive manufacturing techniques.
2. Description of the Related Art
Chemical-mechanical polishing (CMP), also known as chemical mechanical planarization, is a process used in the semiconductor fabrication industry to provide flat surfaces on integrated circuit devices. Referring to FIG. 1, a side sectional view of a typical CMP system 100 is illustrated. CMP system 100 as illustrated shows a substrate 104 disposed in a polishing head 102. The polishing head 102 rotates and presses the substrate 104 against a polishing surface 152 of a polishing pad 150. The polishing pad 150 is supported on a platen 106, which rotates the polishing pad 150 relative to the substrate 104. A polishing fluid or slurry is delivered to the pad 150 from a slurry delivery source 110. The slurry affects removal of films or other materials from the substrate 104. Such polishing is often used to planarize insulating layers, such as silicon oxide and/or metal layers, such as tungsten, aluminum, or copper, that have been deposited on the substrate 104.
Environmental control of the conditions between the polishing pad and the substrate during processing, such as pressure, temperature, and chemistry effect obtaining consistent and uniform polishing results. Pressure during polishing is frequently controlled by varying the amount of downward pressure that the polishing head exerts on the substrate against the polishing pad. While this pressure can be varied, it is often challenging to vary the pressure on different parts of the substrate. Temperature during polishing is often controlled by controlling the temperature of the surrounding air or by supplying coolant through the platen in an attempt to cool the substrate being polished. These indirect methods are often inadequate for precise temperature control of the polished surface of the substrate. Chemicals, such as polishing slurries, are frequently supplied on top of the polishing pad as shown in FIG. 1. Grooves in the polishing pad can be used to transport the slurry to the underside of the substrate being polished. Although some of the slurry does reach the underside of the substrate, large amounts of slurry are typically wasted due to the amounts of slurry that never reach the underside of the substrate.
Therefore, there is a need for improved polishing pads to allow for more efficient and precise control of the temperature, pressure, and chemistry of the conditions between the polishing pad and the substrate being polished.

SUMMARY

In one embodiment, a polishing pad for chemical mechanical polishing is provided. The polishing pad includes a base region having a supporting surface. The polishing pad further includes a plurality of polishing features forming a polishing surface opposing the supporting surface. The polishing pad further includes one or more channels formed in an interior region of the polishing pad, the one or more channels extending at least partly around a center of the polishing pad, wherein each channel is fluidly coupled to at least one port
In another embodiment, a polishing pad for chemical mechanical polishing is provided. The polishing pad includes a base region having a supporting surface. The polishing pad further includes a plurality of polishing features forming a polishing surface opposing the supporting surface. The polishing pad further includes a plenum formed in an interior region of the polishing pad and fluidly coupled to at least one port.
In another embodiment, a polishing device for chemical mechanical polishing is provided. The polishing device includes a platen, a polishing pad, and a seal. The platen includes a shaft and a platen plate supported by the shaft. The platen plate includes a mounting surface for supporting a polishing pad. The platen further includes one or more conduits disposed through the shaft and the platen plate. The polishing pad includes a base region having a supporting surface for contacting the mounting surface of the platen. The polishing pad further includes a plurality of polishing features forming a polishing surface opposing the supporting surface. The polishing pad further includes one or more channels formed in an interior region of the polishing pad and extending at least 15 degrees around a center of the polishing pad. The seal creates a sealed connection between the one or more conduits of the platen and the one or more channels of the polishing pad.
Embodiment of the disclosure may further provide a polishing pad including a composite pad body. The composite pad body includes one or more first features formed from a first material or first composition of materials, and one or more second features formed from a second material or second composition of materials, wherein the one or more first features and the one or more second features are formed by depositing a plurality of layers comprising the first material or first composition of materials and second material or second composition of materials.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1 is a side sectional view of a CMP system.

FIG. 2 is a side sectional view of a polishing device, according to one embodiment.

FIG. 3A is a top plan view of a polishing pad, according to one embodiment.

FIG. 3B is a side sectional view of a polishing device including the polishing pad of FIG. 3A.

FIG. 4A is a top plan view of a polishing pad, according to one embodiment.

FIG. 4B is a side sectional view of the polishing pad of FIG. 4A.

FIG. 5A is a top plan view of a polishing pad, according to one embodiment.

FIG. 5B is a side sectional view of a polishing device including the polishing pad of FIG. 5A, according to one embodiment.

FIG. 6A is a top plan view illustrating a layout of interior channels of a polishing pad and associated equipment, according to one embodiment.

FIG. 6B is a side sectional view of a polishing device, according to one embodiment.

FIG. 7 is a side sectional view of a polishing pad, according to one embodiment.

FIG. 8A is a top plan view of a polishing pad, according to one embodiment.

FIG. 8B is side sectional view of the polishing pad of FIG. 8A.

FIGS. 9A-9H show top views and side views of polishing features that may be incorporated into different embodiments of polishing pads.

FIG. 10 is a process flow diagram, according to one embodiment.

FIG. 11 is an exemplary polishing pad formed using the process of FIG. 10.

FIG. 12A is a top sectional view of a polishing pad and associated equipment, according to one embodiment.

FIG. 12B is a side sectional view of the polishing pad of FIG. 12A.

To facilitate understanding, common words have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

The present disclosure relates generally to the manufacture of polishing articles utilized in chemical mechanical polishing (CMP) processes. More specifically, embodiments disclosed herein are related to polishing pads utilized in CMP processes and methods of fabricating polishing pads using additive manufacturing techniques, such as 3D printing. FIGS. 2-8B describe different embodiments of polishing pads that can be formed with a 3D printing process that is described in reference to FIGS. 10 and 11.
FIG. 2 is a side sectional view of a polishing device 200, according to one embodiment. The polishing device 200 includes a platen 210 and a polishing pad 250. The platen 210 includes a shaft 214 and a platen plate 216 supported by the shaft 214. The platen plate 216 includes a mounting surface 218 for supporting the polishing pad 250. The platen 210 further includes a first conduit 211 and a second conduit 212 for transporting fluid to and/or from the polishing pad 250. Each conduit 211, 212 is distributed through the shaft 214 and the platen plate 216. In some embodiments, one or more conduits can be distributed through the shaft and platen plate. The different conduits can transport the same fluid or different fluids, such as polishing slurries, surfactants, deionized water, solvents, mixtures, or other fluids. The conduits 211, 212 can be distributed through respective openings 221, 222 of a sealing surface 232 or another surface of the platen 210, such as another surface facing the polishing pad 250, such as the mounting surface 218.
The polishing pad 250 includes a base region 260 having a supporting surface 254 contacting the mounting surface 218 of the platen 210. The polishing pad 250 further includes a polishing region that includes a plurality of polishing features 271 forming a polishing surface 274. The polishing surface 274 opposes the supporting surface 254.
The polishing pad 250 as well as the other polishing pads discussed below can be formed of a polymer, such as polyurethane, polyurethane-acrylate, epoxy, acrylonitrile, butadiene styrene (ABS), polyetheramide, polyesters, nylons, polyphenylsulfones (PPS), polyetherketones (PEEK) polyvinylacohols, polyvinylacetate, polyvinyl chloride, polycarbonate, polyamide, or copolymers and blends thereof as well as photopolymer acrylate monomers and oligomers, such as polyurethane acrylate, polyester acrylate, and epoxy acetate. The base region 260 and the polishing region 270 can be formed of the same or different material. For example, in some embodiments, the base region 260 can be formed of polysilicon while the polishing region 270 can be formed of polyurethane. The polishing region can have a hardness of between about 40 on the Shore A scale and about 90 on the Shore D scale, such as about 50 on the Shore D scale. The polishing region 270 can have a thickness of between about 15 mils and about 80 mils, such as about 50 mils. The polishing features 271 can have dimensions in a plane parallel to the polishing surface between about 50 microns and about 5000 microns, such as about 150 microns. The polishing features can have a textured polishing surface with roughened features having dimensions of between about 1 microns and about 10 microns, such as about 2 microns. The polishing features 271 can cover between about 15% and about 90% of the total horizontal surface area of the polishing pad 250. A gap 277 between polishing features can be between about 2.5 mm down to about 100 microns, such as 300 microns. The height of the polishing features 271 can be between about 0.1 mm to about 1.5 mm, such as about 0.5 mm. The base region 260 can be softer or harder than the polishing region 270. The thickness of the base region 260 can be thicker, thinner or the same as the thickness of the polishing region 270. The dimensions and properties of the polishing pad 250 discussed in this paragraph apply to all of the polishing pads discussed below unless specified otherwise.
The polishing pad 250 further includes a first channel 251 and a second channel 252 formed in an interior region of the polishing pad 250. The first channel 251 and the second channel 252 can extend at least partly around a center 257 of the polishing pad 250. For example, in some embodiments, the first channel 251 and the second channel 252 can extend at least 15 degrees around the center 257 of the polishing pad 250. In some embodiments the first channel 251 and the second channel 252 can extend completely around the center 257 of the polishing pad 250 (i.e., 360 degrees). The channels 251, 252 terminate at respective ports 241, 242. The ports 241, 242 can be formed in the supporting surface 254 of the polishing pad 250 or another surface, such as another surface facing the platen 210. In some embodiments, the polishing pad can include one or more ports on a side of the polishing pad, such as a side that is perpendicular to the supporting surface 254.
In some embodiments, the polishing pad may contain one or more channels, such as 100 channels, formed in the interior region of the polishing pad, and the one or more channels can each extend at least partly around a center of the polishing pad. Each of the one or more channels can be fluidly coupled to at least one port.
The polishing device 200 further includes a seal 230 creating a sealed connection between the first conduit 211 and the first channel 251 and creating a sealed connection between the second conduit 212 and the second channel 252. The seal 230 can interface with respective openings 221, 222 on the platen 210 and the respective ports 241, 242 of the polishing pad 250. In some embodiments, the seal 230 can create a sealed connection between the one or more conduits of the platen and the one or more channels of the polishing pad.
The following embodiments provide examples of how polishing pads having interior channels can be used to improve the polishing process results, improve the cost of ownership, and reduce the polishing process consumable costs. The polishing pads having internal channels can be fabricated using additive manufacturing techniques, such as 3D printing. FIGS. 10 and 11 below describe a process of fabricating a polishing pad having internal channels using 3D printing.
FIG. 3A is a top plan view illustrating a layout of interior channels of a polishing pad 350, according to one embodiment. FIG. 3B is a side sectional view of a polishing device 300 including the polishing pad 350 of FIG. 3A. The polishing device 300 further includes a platen 310 and a seal 330. The polishing pad 350 includes a plenum 355, an inner channel 351, and an outer channel 352 that can each be connected to a different conduit formed in the platen 310, which is discussed in further detail below. These separate connections can be coupled to a high pressure source 380, such as a compressed air supply, to allow the pressures inside the plenum 355, the inner channel 351, and the outer channel 352 to be individually controlled.
The plenum 355 is formed in an interior region of the polishing pad 350. The plenum 355 is fluidly coupled to a port 345 allowing a fluid connection to a conduit 315 of the platen 310 through the seal 330. The inner channel 351 is fluidly coupled to a port 341 allowing a fluid connection to a conduit 311 of the platen 310 through the seal 330. The outer channel 352 is fluidly coupled to a port 342 allowing a fluid connection to a conduit 312 of the platen 310 through the seal 330. The plenum 355 is substantially surrounded by the inner channel 351. The inner channel 351 is substantially surrounded by the outer channel 352. In some embodiments, each channel 351, 352 can extend at least partly around (e.g., 15 degrees) a center 357 of the polishing pad 350. At least two of the channels 351, 352 are fluidly coupled to a separate port, such as ports 341, 342, respectively. At least two of the channels 351, 352 are fluidly coupled to a separate conduit of the conduits 311, 312. Although a narrow line is shown in FIG. 3A separating the channels 351, 352 and the plenum 355 from the channels 351, 352, the separation between the channels 351, 352 from each other and from the plenum 355 can be greater than the widths of the channels 351, 352 in some embodiments.
The plenum 355 can be disposed adjacent to plenum polishing features 375, such as beneath plenum polishing features 375. The inner channel 351 can be disposed adjacent to inner polishing features 371, such as beneath inner polishing features 371. The outer channel 352 can be disposed adjacent to outer polishing features 372, such as beneath outer polishing features 372. During operation, the plenum 355, the inner channel 351, and the outer channel 352 can be pressurized at different pressures, such as being pressurized with a different fluid pressure (e.g., air pressure). Applying more or less pressure to the plenum 355 and channels 351, 352 relative to each other can provide advantages, such as alleviating center to edge non-uniformities and adjusting the short and long range planarization of the polished surface of a substrate during a CMP process. In some configurations, the pressure and/or type of fluid provided to one or more of the plenums and channels can be used to adjust the dynamic properties of the polishing pad, and thus affect the polishing process results. Two common CMP pad dynamic properties that can be adjusted are the loss modulus and the storage modulus. In conventional applications a CMP pad's dynamic properties could only be modified by adjusting the material composition and/or pad formation process variables to alter a formed pad's material properties. The storage modulus property of a CMP pad represents the modulus of the elastic portion of the material. Hence, storage modulus is a measure of the energy stored in the material and recovered per cycle as the pad is passed beneath the substrate that is being polished. Conversely, the loss modulus relates to the viscous nature or property of the pad material, or in this case pad stack. The loss modulus is a measure of the energy dissipated as heat due to the cyclic deformation of the pad during polishing. The ratio of the loss to the storage modulus is defined as tan delta (δ) and represents the material's ability to dissipate energy. Adjusting the storage and loss modulus properties of a pad stack will affect the long and short range planarization of the polished surface of the substrate. As will be discussed further below, by adjusting the pressure and/or material disposed within the plenums and channels the dynamic properties and thus planarization ability of the polishing pad 350 can be adjusted.
Although three pressure zones are shown in FIGS. 3A-3B (i.e., plenum 355 and channels 351, 352), other embodiments can include two or more zones, such as ten zones. In some embodiments, the material surrounding the plenum 355 and channels 351, 352 can be a different material from the polishing region or base region of the polishing pad 350, such as a softer and/or more flexible material. For example, in some embodiments, the different parts of the polishing pad 350 can all be formed of polyurethane, but the material surrounding the plenum 355 and channels 351, 352 can be made of softer material than the material comprising the remainder of the polishing pad 350 to enable greater flexibility of the material surrounding the plenum 355 and the channels 351, 352 and/or for adjustment of the dynamic properties of the polishing pad stack. In other embodiments, all of the polishing pad 350 can be formed of the same material.
The polishing pad 350 may also include one or more sensors, such as one or more pressure sensors or temperature sensors. For example, the polishing pad 350 may include a plenum pressure sensor 365, an inner channel pressure sensor 361, and an outer channel pressure sensor 362. In one example, the pressure sensor may include a strain gauge type device that provides a signal that is used to determine the amount of applied pressure. The plenum pressure sensor 365 can have a sensing surface that is positioned in the plenum 355 to determine the pressure inside the plenum 355. The inner channel pressure sensor 361 can have a sensing surface that is positioned in the inner channel 351 to determine the pressure inside the inner channel 351. The outer channel pressure sensor 362 can have a sensing surface that is positioned in the outer channel 352 to determine the pressure inside the outer channel 352. Each of the pressure sensors 365, 361, 362 may communicate the determined pressure to a controller 25 through a wired or wireless connection. The controller 25 can be any controller capable of monitoring inputs and/or controlling outputs, such as any microprocessor, microcomputer, or programmable logic controller.
A pressure regulating device, such as control valve, may be placed between the high pressure source 380 and each of the plenum 355 and the channels 351, 352. A control valve 385 may be placed between the high pressure source 380 and the plenum 355. Control valves 381, 382 may be placed between the high pressure source 380 and the inner channel 351 and outer channel 352 respectively. The control valves 385, 381, 382 may be placed at a location remote from the platen 310. The controller 25 can control the pressures inside the plenum 355 and the channels 351, 352 by adjusting the position of the control valves. In one embodiment, the controller 25 executes an individual feedback loop, such as a PID loop, for each pair of the pressure sensors and control valves for the plenum 355 and the channels 351, 352. In some embodiments, additional pressure sensors may be placed at other locations in the polishing pad 350, such as positions closer to the seal 330, to provide further data of the pressure inside the polishing pad 350.
In some embodiments, the high pressure source 380 is a compressed air supply, but other fluids may also be used such as DI water or another useful fluid. For example, in some embodiments a compressed inert gas is used as the fluid of the high pressure source.
In other embodiments, a non-Newtonian fluid can be used as the fluid of the high pressure source. Examples of non-Newtonian fluids that may be used include polysaccharide solutions and polyethylene glycol solutions, either of which may also include ceramic particles. Filling the plenum 355 and the channels 351, 352 of the polishing pad 350 with a non-Newtonian fluid allows the elastic and damping characteristics of the polishing pad 350 to be adjusted. The elastic and damping characteristics of the polishing pad determine how the polishing pad responds to stresses during polishing. For example, an overly elastic polishing pad can cause “dishing” or areas that have too much material removed from the surface being polished. This unwanted dishing results in a non-planar polish and can result in poor performance of the device produced. A highly inelastic polishing pad can be too stiff to conform to the variations in the surface to be polished causing poor polishing results. In one example, smaller features formed on a surface of a semiconductor substrate, such as tightly spaced 32 nm line features versus much wider sized and spaced trenches, may have completely different polishing characteristics. Therefore, the damping characteristic of the non-Newtonian fluid will enable the supplied fluid to absorb energy and stresses during polishing, which prevents excessive vibrations between the polishing pad and the substrate. The stress and shear-thickening properties of the non-Newtonian fluid cause the fluid to harden in response to the stress and absorb the energy. On the other hand, Newtonian fluids do not have these stress and shear-thickening properties, which makes Newtonian fluids less effective at absorbing the energy and stresses generated during polishing.
The elasticity and damping characteristics of the polishing pad 350 (e.g., polishing pad's dynamic properties) can be adjusted by changing the fluid type, such as the non-Newtonian fluid, and fluid pressure supplied to the plenum 355 and the channels 351, 352. Previously, to achieve different elastic and damping characteristics, a different polishing pad would be used, but now one pad may be filled with different fluids to obtain different elastic and damping characteristics. Furthermore, in some embodiments, a different fluid, such as a different non-Newtonian may be supplied to one or more of the plenum 355 or the channels 351, 352, which enables the elastic and damping characteristics to be adjusted for different areas of the polishing pad, such as different radial areas of the polishing pad.
FIG. 4A is a top plan view illustrating a layout of interior channels of a polishing pad 450, according to one embodiment. FIG. 4B is a partial side sectional view of the polishing pad 450 of FIG. 4A. The polishing pad 450 includes a first polishing channel 451, a second polishing channel 452, and a third polishing channel 453. The channels 451-453 are each fluidly coupled to a supply channel 461. The channels 451-453 can extend substantially around a center 457 of the polishing pad 450, such as 360 degrees around the center 457 of the polishing pad 450.
The polishing pad 450 further includes a plurality of polishing features, which include adjustable polishing features 471 and fixed polishing features 472. The adjustable polishing features 471 can move relative to the fixed polishing features 472, so that when pressure, such as air pressure, is applied to channels 451-453, then the adjustable polishing features 471 can extend past the fixed polishing features 472 to polish the substrate. When the pressure is removed, then the adjustable polishing features 471 can return to a recessed position relative to the fixed polishing features 472, so that the fixed polishing features 472 can polish the substrate. The adjustable polishing features 471 can include a first polishing surface 481 and the fixed polishing features can include a second polishing surface 482. The first polishing surface 481 may have different properties than the second polishing surface 482, such as having a different hardness or texture. Each of the channels 451-453 can be disposed adjacent to at least some of the adjustable polishing features 471, such as beneath the adjustable polishing features 471. For example, the adjustable polishing features 471 can be disposed along concentric rings above the channels 451-453. The fixed polishing features 472 can be disposed along areas of the polishing pad not occupied by the concentric rings disposed above the channels 451-453.
The adjustable polishing features 471 can move in response to pressure changes in the channels 451-453, such as extending past the fixed polishing features 472 when the pressure in the channels 451-453 rises above a certain level. The adjustable polishing features 471 can have different properties than the fixed polishing features 472, such as a different shape, size, hardness, composition. The adjustable polishing features 471 can be recessed relative to the fixed polishing features 472 when the channels 451-453 are not pressurized. When the channels 451-453 are pressurized, the adjustable polishing features 471 can extend past the fixed polishing features 472. During operation, air pressure can be supplied from a source to the polishing pad 450, such as through a conduit of a platen (not shown), to pressurize supply channel 461 and channels 451-453 allowing the adjustable polishing features 471 to extend past the fixed polishing features 472.
Polishing pad 450 enables the use of one polishing pad to polish a substrate with different polishing features at different times. For example, if the fixed polishing features 472 are harder or have a rougher texture than the adjustable polishing features 471, then the fixed polishing features 472 can first be used for a rougher polish and then channels 451-453 can be pressurized to allow the adjustable polishing features 471 to be used for a finer polish. In one embodiment, the adjustable polishing features 471 can have a hardness between about 15 to about 25 on the Shore D scale (e.g., about 20 on the Shore D scale) and the fixed polishing features 472 can have a hardness between about 50 to about 70 on the Shore D scale (e.g., about 60 on the Shore D scale). Although only three channels 451-453 are shown extending around the center 457 of the polishing pad 450, two or more than three channels can be included. Although only one supply channel 461 is shown, some embodiments can include multiple supply channels to allow different channels of the polishing pad to receive different pressures, similar to how the channels 351, 352 of the polishing pad 350 can receive different pressures. Separate supply channels can also be used in embodiments having more than one set of adjustable polishing features. For example, a polishing pad may include a first set of adjustable polishing features for applying a medium polish and a second set of adjustable polishing features for applying a finer polish as well as fixed polishing features for applying a rougher polish. In some embodiments, the polishing pad 450 can include one or more pressure sensors (not shown), such as the pressure sensors included in the polishing pad 350. For example, the polishing pad may include a pressure sensor in or more of the channels 451-453.
In some embodiments, the supply channel 461 can lead to a plenum that can pressurize all of the adjustable polishing features instead of using separate channels, such as the channels 451-453. The plenum can be adjacent to substantially all of the adjustable polishing features 471 and the fixed polishing features 472. The polishing pad having the plenum can prevent the fixed features 472 from moving in response to air pressure changes by having additional or different material between the plenum and the fixed features 472 relative to the adjustable polishing features 471. For example, a more flexible material can be placed between the adjustable polishing features 471 and the plenum than between the fixed polishing features 472 and the plenum.
FIG. 5A is a top plan view illustrating a layout of interior channels of a polishing pad 550, according to one embodiment. FIG. 5B is a side sectional view of a polishing device 500 including the polishing pad 550 of FIG. 5A. The polishing device 500 includes the polishing pad 550, a platen 510, and a seal 530 providing a sealed connection between the polishing pad 550 to the platen 510. The platen 510 includes a supply conduit 511 and a return conduit 512. The supply conduit 511 and return conduit 512 can be used to flow a fluid through the polishing pad 550. For example, the conduits 511, 512 can be used to flow a heating or cooling fluid through the polishing pad 550 to adjust the temperature of the polishing process to adjust the activity of the slurry chemistry and/or adjust the dynamic properties of the polishing pad.
The polishing pad 550 includes a plurality of channels 551-556. Although a narrow line is shown in FIG. 5A separating the channels 551-556, the channels 551-556 can be separated by distances greater than the widths of the channels in some embodiments. Each channel 551-556 can substantially surround a center 557 of the polishing pad 550, such as about 360 degrees around the center 557 of the polishing pad 550. Each channel 551-556 is adjacent to polishing features 571 of the polishing pad 550. An outward facing surface of the polishing features 571 forms a polishing surface 574 of the polishing pad 550. Each of the channels 551-556 is fluidly coupled to a supply channel 561 and a supply port 541, and each of the channels 551-556 is also fluidly coupled to a return channel 562 and a return port 542. In some embodiments, an outer ring 559 that does not include a channel can be included in the polishing pad 550 to provide additional structural support for the polishing pad 550.
The supply channel 561 and the return channel 562 can extend substantially from the center 557 of the polishing pad 550 to an outer edge of the outermost channel 556. The supply channel 561 and the return channel 562 can be disposed adjacent to each other. The supply channel 561 and the return channel 562 can be disposed adjacent to the channels 551-556, such as coupling to the channels 551-56 from beneath the channels 551-556. Disposing the supply channel 561, the return channel 562 and the channels 551-556 in this arrangement allows fluid flowing through the channels 551-556 to form a substantially complete loop around the center 557 of the polishing pad 550. A barrier 591 can be used to ensure that fluid flows around the innermost channel 551 before exiting through the return channel 562.
The seal 530 provides a sealed connection between the supply conduit 511 and the supply channel 561 and couples the return conduit 512 to the return channel 562. The seal 530 can interface with respective openings 521, 522 on the platen 510 and the respective ports 541, 542 of the polishing pad 550. Each channel 551-556 is fluidly coupled to the two conduits 511, 512 of the platen 510 through the seal 530.
As noted above, during operation, a heating or cooling fluid, such as chilled water, can be flowed through the channels 551-556 to provide temperature control of the polishing pad 550 and the polishing surface 574. In some embodiments, a heating fluid is first circulated through the polishing pad to bring the polishing pad up to a specified temperature, and then during polishing a coolant may be circulated through the polishing pad. The flow rate or temperature of the coolant can be adjusted to provide more or less cooling.
Although six channels 551-556 are shown, more or less channels can be included. In some embodiments, additional structures, such as fin-shaped structures, may be placed in the channels 551-556 to provide additional surface area for heat transfer between the polishing pad 550 and the coolant. The fin-shaped structures can extend from one or more of the side walls of the channels 551-556. In some embodiments, other arrangements of channels may be used for heat transfer. For example, in one embodiment the channels can form one or more than one loops around the center of polishing pad spiraling toward or away from the center of the polishing pad. In other embodiments, the channels can form less than a complete loop around a center of the polishing pad.
Flowing the coolant directly through the polishing pad provides better temperature control of the polishing surface 574 than indirect methods, such as cooling the platen. The improved temperature control results in improved polishing, such as more uniform polishing and more consistent polishing rates.
FIG. 6A is a top plan view illustrating a layout of interior channels of a polishing pad 650 and associated equipment, according to one embodiment. FIG. 6B is a partial side sectional view of a polishing device 600 including the polishing pad 650 of FIG. 6A. The polishing device 600 includes a polishing pad 650 and a platen 610. The platen 610 can include one supply conduit (not visible in the cross section of FIG. 6B) and multiple return conduits 621-626. The supply conduit can be located directly beneath a main supply channel 641M shown in FIG. 6A. The supply conduit and return conduits 621-626 can be used to flow a fluid through the polishing pad 650. For example, the supply conduit and the return conduits 621-626 can be used to flow a heating or cooling fluid, such as cooling water, through the polishing pad 650. The multiple return conduits 621-626 allow for separate temperature control of different areas of the polishing pad 650.
The polishing pad 650 includes a plurality of channels 651-656. Although a narrow line is shown in FIG. 6A separating the channels 651-656, the channels 651-656 can be separated by distances greater than the widths of the channels in some embodiments. Each channel 651-656 can substantially surround a center 657 of the polishing pad 650, such as about 360 degrees around the center 657 of the polishing pad 650. Each channel 651-656 is adjacent to polishing features 671 of the polishing pad 650. An outward facing surface of the polishing features 671 forms a polishing surface 674 of the polishing pad 650. Each of the channels 651-656 is fluidly coupled to a common supply channel 641 and a respective individual return channel 651R-656R. The supply channel 641 is fluidly coupled to a main supply channel 641M and a port (not shown). The return channels 651R-656R are fluidly coupled to respective ports 651P-656P. Each channel 651-656 is fluidly coupled to a separate respective conduit 621-626 through the respective return channels 651R-656R, ports 651P-656P, and seals 631-636. In some embodiments, an outer ring 659 that does not include a channel can be included in the polishing pad 650 to provide additional structural support for the polishing pad 650.
The supply channel 641 and the array of the return channels 651R-656R can extend substantially from the center 657 of the polishing pad 650 to an outer edge of the outermost channel 656. The supply channel 641 and the return channels 651R-656R can be disposed adjacent to each other. The supply channel 641 and the array of return channels 651R-656R can be disposed adjacent to the channels 651-656, such as beneath the channels 651-656. Disposing the supply channel 641, the return channels 651R-656R, and the channels 651-656 in this arrangement allows fluid flowing through the channels 651-656 to form a substantially complete loop around the center 657 of the polishing pad 650. A barrier 691 can be used to ensure that fluid flows around the innermost channel 651 before exiting through the return channel 651R.
During operation, a coolant from a coolant supply 680 can be flowed through the channels 651-656 using one or more pumps (not shown) to provide temperature control of the polishing pad 650 and the polishing surface 674. Coupling the individual return channels 651R-656R to the individual return conduits 621-626 through the seals 631-636 allows separate temperature control of different areas of the polishing surface 674. For example, individual control valves 681-686 can be placed downstream of the respective return conduits 621-626 and remote from the platen 610 to enable the separate temperature control of each channel 651-656. The flow or temperature of the coolant can be adjusted to provide more or less cooling to each channel 651-656.
The polishing pad 650 may also include one or more sensors, such as one or more temperature sensors. For example, the polishing pad 650 may include a temperature sensor 661-666 positioned in each of the respective channels 651-656 to measure the temperature of that channel 651-656. In another example, one or more of the temperature sensors 661-666 may be positioned at or near the polishing surface of the polishing pad 350 (e.g., exposed surface of the pad), so that the temperature of the surface of polishing pad and substrate can be measured during the polishing process. The temperature sensors 661-666 may include a thermocouple, RTD or similar type of temperature measurement device. Each of the temperature sensors 661-666 may communicate the measured temperature to a controller, such as the controller 25 described above in reference to FIGS. 3A and 3B. The communication between the temperature sensors 661-666 and the controller 25 may be wired or wireless. The controller 25 can control the temperatures inside the channels 651-656 by adjusting the position of the control valves 681-686. In one embodiment, the controller 25 executes an individual feedback loop, such as a PID loop, for each pair of the temperature sensors and control valves for the different channels 651-656. In some embodiments, additional temperature sensors may be placed at other locations in the polishing pad 650, such as in the main supply channel 641M, to provide further data of the temperature inside the polishing pad 650.
A supply control valve 690 may also be placed between the coolant supply 680 and the main supply channel 641M to control the overall flow of coolant to the polishing pad. In some embodiments, each channel 651-656 has a separate supply conduit and separate return conduit, so that the adjustments made to a control valve coupled to, for example a first channel of the polishing pad do not affect the flow of heating or cooling fluid to one or more of the other channels of the polishing pad 650. Flowing the coolant directly through the polishing pad provides better temperature control of the polishing surface than indirect methods, such as cooling the platen. The improved temperature control results in improved polishing, such as more uniform polishing and more consistent polishing rates. Although not discussed above in reference to FIGS. 5A and 5B, the polishing pad 550 may also include one or more temperature sensors to enable temperature control of the polishing pad 550 in a similar fashion to the temperature control of the polishing pad 650.
In some embodiments, additional structures, such as fin-shaped structures, may be placed in the channels 651-656 to provide additional surface area for heat transfer between the polishing pad 650 and the coolant. The fin-shaped structures can extend from one or more of the side walls of the channels 651-656. In some embodiments, other arrangements of channels may be used for heat transfer. For example, in one embodiment the channels can form one or more loops around the center of polishing pad spiraling toward or away from the center of the polishing pad. In other embodiments, the channels may extend less than a complete loop around a center of the polishing pad.
FIG. 7 is a partial side sectional view of a polishing pad 750, according to one embodiment. The polishing pad 750 can have a generally circular shape similar to the other polishing pads discussed above. The polishing pad 750 includes a supply channel 761 and a plenum 765. The plenum 765 can be disposed adjacent to a polishing surface 774, such as beneath polishing surface 774. The polishing pad 750 further includes polishing features 771. Each polishing feature 771 can include a polishing feature channel 775. The polishing feature channel 775 can be used along with the supply channel 761 and plenum 765 to deliver fluids to an aperture 776 in the polishing surface 774.
Fluids delivered to the polishing surface 774 through the polishing feature channel 775 can include fluids, such as slurries, surfactants, deionized water and other fluids. The fluids can be delivered through one or more conduits of a platen (not shown). In some embodiments, a slurry can be delivered through the supply channel 761 and other fluids, such as surfactants and deionized water can be delivered through auxiliary channels (not shown). The supply channel 761 and the auxiliary channels can have ports on a surface of the polishing pad 750, such as a bottom surface of a polishing pad 750. Delivering fluids directly out of the polishing features ensures the fluid is provided between the substrate being polished and the polishing pad.
FIG. 8A is a top plan view illustrating a layout of interior channels of a polishing pad 850, according to one embodiment. FIG. 8B is a partial side sectional view of the polishing pad 850 of FIG. 8A. The polishing pad 850 includes a first polishing channel 851, a second polishing channel 852, and a third polishing channel 853. The channels 851-853 can extend substantially around a center 857 of the polishing pad 850, such as 360 degrees around the center 857 of the polishing pad 450. Channels 851-853 are each fluidly coupled to a common supply channel 861.
The polishing pad 850 further includes a plurality of polishing features, which include first polishing features 871 and second polishing features 872. Each first polishing feature 871 can include a polishing feature channel 875. Each polishing feature channel 875 can be used along with the supply channel 861 to deliver fluids to an aperture 876 at an end of the first polishing feature 871 through the polishing surface 874. The first polishing features 871 each have an aperture 876 through the polishing surface 874, and the second polishing features 872 each lack an aperture through the polishing surface 874. Each of the channels 851-853 can be disposed adjacent to at least some of the first polishing features 871, such as beneath the first polishing features 871. The second polishing features 872 can be disposed between the channels 851-853, so that a ring of the first polishing features 871 can surround a ring of the second polishing features 872.
The first polishing features 871 can be used to deliver fluids, such as slurry, surfactants, and deionized water, to the polishing surface 874. The fluids can be delivered through one or more conduits of a platen (not shown). In some embodiments, a slurry can be delivered through the supply channel 861 and other fluids, such as surfactants and deionized water can be delivered through auxiliary channels (not shown). The supply channel 861 and the auxiliary channels can have ports on a surface of the polishing pad 850, such as a bottom surface of a polishing pad 850.
Delivering fluids directly out of the polishing features ensures the fluid is provided between the substrate being polished and the polishing pad. Although the polishing pad 850 has alternating rings of first polishing features 871 that deliver fluids and second polishing features 872 that do not deliver fluids, other arrangements may be used. For example, there can more or less first polishing features 871 than second polishing features 872. There may also be first polishing features 871 and second polishing features 872 included in a same ring around the center 857 of the polishing pad 850. In some embodiments, different channels may be fluidly coupled to different conduits of a platen, so that different areas of the polishing pad can receive different amounts of fluids. For example, if a substrate is significantly smaller than the polishing pad, and the substrate is being polished near the edge of the polishing pad, then most or all of the fluids can be provided to the edge of the polishing pad 850 while less or none of the fluids can be provided to the center of the polishing pad. Such a design can save material costs by using less fluids, such as the slurries used during CMP.
FIGS. 9A-9H show top views and side views of some of the different shapes that the polishing features discussed above can have. In some embodiments, the polishing features discussed above can take the shape of a cylinder. FIG. 9A shows a top view of a polishing feature 910 having a cylindrical shape. FIG. 9B shows a side view of the polishing feature 910 having a first side 911 connected to the polishing pad (not shown) and second side 912 forming part of the polishing surface of the polishing pad. In other embodiments, the polishing features discussed above can take the shape of a prism having a cross section of any polygon, such as a triangle, square, rectangle, pentagon, hexagon, etc. FIG. 9C shows a top view of a polishing feature 920 having a shape of a rectangular prism. FIG. 9D shows a side view of the polishing feature 920 having a first side 921 connected to the polishing pad (not shown) and second side 922 forming part of the polishing surface of the polishing pad.
In still other embodiments, the polishing features discussed above can take the shape of a fin. In some of these embodiments, the fin can take the shape of a rectangular prism, where one dimension of the cross section is more than double the length of the other direction. In other embodiments, the fins can include other shapes, such as curved features allowing the fin to follow the curvature of a round polishing pad. FIG. 9E shows a top view of a polishing feature 930 having a shape of a fin in the form of a rectangular prism, where a first dimension 936 is more than double the length of a second dimension 937. FIG. 9F shows a side view of the polishing feature 930 having a first side 931 connected to the polishing pad (not shown) and second side 932 forming part of the polishing surface of the polishing pad.
In still other embodiments, the polishing features discussed above can take the shape of a cone or pyramid, such as a truncated cone or pyramid. FIG. 9G shows a top view of a polishing feature 940 having a shape of a truncated cone. FIG. 9H shows a side view of the polishing feature 940 having a first side 941 connected to the polishing pad (not shown) and second side 942 forming part of the polishing surface of the polishing pad.
Using a polishing surface formed of individual polishing features, such as the polishing features discussed in reference to FIGS. 9A-9H, provides numerous advantages. Polishing pads that do not use individual polishing features have typically used grooves, such as grooves forming concentric rings. These grooves have typically been formed by removing material from the surface of the polishing pad. While these grooves may allow for adequate fluid transfer within the grooves, the walls between the grooves inhibit the fluid transfer between the grooves. On the other hand, when individual polishing features are used, the fluid can flow around the individual features and there are no large structures, such as walls between grooves, to inhibit fluid transfer in any direction on the surface of the polishing pad. When fluids, such as slurries, cannot be adequately provided to areas of the polishing pad beneath the polishing head and substrate, fluids, such as slurry can be wasted. Wasting slurry can lower the efficiency of the polishing process and increase costs. Individual features can promote the transfer of fluids, such as slurry, to the areas of the polishing pad beneath the polishing head and substrate reducing waste and increasing efficiency.
Individual polishing features also allow for designs having multiple types of polishing features, where the different types of polishing features can perform different functions. For example, polishing pad 450 discussed above allows for polishing with either adjustable polishing features 471 or fixed polishing features 472 enabling two or more types of polishing results to be obtained with one polishing pad, such as a rough polish followed by a finer polish. The individual features can be formed using additive manufacturing techniques, such as 3D printing.
FIG. 10 is a process flow diagram summarizing a process 1000 for forming a polishing pad having one or more internal channels by using a 3D printer. FIG. 11 shows a 3D printer 50 that can be used to perform the process 1000 to form a polishing pad, such as the polishing pad 250 discussed above in reference to FIG. 2 and shown again in FIG. 11. Although the following describes the process 1000 by using the polishing pad 250 as an exemplary polishing pad that can be fabricated using the process 1000, any of the polishing pads discussed above in reference to FIGS. 2-8B as well as the polishing features of FIGS. 9A-9H can be formed using the process 1000.
The 3D printer 50 can use a jetted photopolymer process to deposit drops of photopolymer followed by a UV cure to form the structure of the polishing pad 250. The 3D printer 50 can print successive layers of the photopolymer material and one or more other materials to form the polishing pad 250. The 3D printer 50 can use one or more print-heads to deposit build material and support material. The build material to form the polishing pad 250 can be a photopolymer, such as an acrylic terminated polyurethane or any polymer such as polyesters, nylons, polyphenylsulfones (PPS), polyetherketones (PEEK) polyvinylacohols, polyvinylacetate polyvinyl chloride, polycarbonate, or polyamide as well as copolymers and blends thereof. The build material could also include photopolymer acrylate monomers and oligomers, such as polyurethane acrylate, polyester acrylate, and epoxy acrylate. Other materials that can be used to form the polishing pad 250 include polyurethane-acrylate, epoxy, acrylonitrile butadiene styrene (ABS), polyetherimide, or polyamide. The support material can also be a photopolymer, or the support material can be a different material, such as another polymer, a wax, or a water-soluble material. The support material is used to fill any voids and support any overhangs of the polishing pad 250 during the printing process. After the polishing pad 250 is formed, the support material can be selectively removed from the polishing pad 250 using processes, such as phase change, dissolution, chemical reaction, or mechanical processes. Although a jetted photopolymer 3D printing process is described for the process 1000, other 3D printing processes can be used, such as stereolithography (SLA), selective laser sintering (SLS), or fused filament fabrication (FFF).
At block 1002, a 3D model of the polishing pad 250 is loaded into the 3D printer 50 in a format to enable 3D-printing, such as STL. At block 1004, the 3D printer 50 begins printing by depositing an initial base layer 260 _ion a platform 70. The platform 70 can be a metallic, plastic, or ceramic material, such as aluminum, titanium, iron, stainless steel, alumina (Al2O3), silicon, silicon oxide, or silicon carbide. If the platform 70 is formed of a metallic material, then the metals may be plated or anodized to improve release properties. The platform 70 can be coated with a non-stick material, such as polytetrafluoroethylene. The initial base layer 260 _iincludes build material and support material. The 3D printer deposits the build material to form the structure of the polishing pad 250. The 3D printer 50 deposits the support material (not shown) to fill any voids or gaps between areas of the build material, such as the ports 241, 242. The support material may also be deposited around the perimeter of the polishing pad 250. The ports 241, 242 can be used fluidly couple the polishing pad 250 to fluid from the platen or another source. After or as the initial base layer 260 _iis deposited, the build material of the initial base layer 260 _iis cured using UV energy. The support material is also solidified through a curing, phase change or another process.
At block 1006, the 3D printer 50 deposits additional base layers over the initial base layer 260 _ito form the base region 260. The 3D printer deposits build material in the additional layers to form the structure of the polishing pad 250 and deposits support material to fill any voids or gaps in the polishing pad 250, such as channels 251, 252. Each layer of build material is cured with the UV energy before the next layer is deposited. The support material may also continue to be deposited around the perimeter of the polishing pad 250 to provide additional support. In some embodiments, the process 1000 may be paused during block 1006 for the installation of one or more sensors, such as the pressure and temperature sensors discussed above in reference to FIGS. 3A, 3B and FIGS. 6A, 6B. In some embodiments, the 3D printer 50 can form a recess in which the sensor is placed, and then the 3D printer 50 may form successive layers around the sensor to secure the sensor in place. In other embodiments, the 3D printer 50 can deposit build material, which will later be removed to form one or more ports from the outside of a polishing pad to one of the channels inside the polishing pad. For example, one or more ports may be formed on the side of the polishing pad that faces the platen during polishing. By using externally accessible ports to the channels of a polishing pad, sensors may more easily be removed from the polishing pad. Removal of a sensor may be useful if a sensor malfunctions and needs to be replaced as well as removal of a sensor for use in another polishing pad, for example when a polishing pad has reached the end of its useful life.
At block 1008, the 3D printer 50 deposits polishing layers over the base region 260 to form the polishing region 270. In some embodiments, the base region 260 and the polishing region 270 are formed of the same material, such as polyurethane. In other embodiments, the base region 260 and the polishing region 270 can be formed of different materials. The 3D printer 50 can form the polishing region 270 and the polishing features 271 of the build material. The 3D printer 50 can deposit support material (not shown) between the polishing features 271. For embodiments, such as polishing pad 750 or polishing pad 850, the 3D printer 50 can deposit support material to form the channels through the polishing features, such as polishing feature channels 775, 875.
At block 1010, the support material is removed from the polishing pad 250. Depending on the type of support material used, the support material can be removed through phase change, dissolution, chemical reaction, or other processes. For example, when a water soluble support material is used, the polishing pad 250 can be soaked in a bath of water to remove the support material.
In another embodiment the 3D printer 50 can be used to form a polishing pad having a composite pad body. The composite pad body includes discrete features formed from at last two different materials. The polishing pad may be produced by a three-dimensional (3D) printing process similar to the process 1000. For example, the composite pad body may be formed by successively depositing a plurality of layers, each layer including regions of different materials or different compositions of materials, by the 3D printer 50. The plurality of layers can then be solidified by curing. The discrete features in the composite pad body may be formed simultaneously from different materials or different compositions of materials. The depositing and curing process of 3D printing allow the discrete features to be securely joined together. The geometry of the discrete features may be easily controlled using the 3D printing process. By choosing different materials or different compositions of materials, the discrete features may have different mechanical, physical, chemical, and/or geometry properties to obtain specified pad properties. In one embodiment, the composite body may be formed from viscoelastic materials having different mechanical properties. For example the composite body may be formed from viscoelastic materials having different storage moduli and different loss moduli. As a result, the composite pad body may include some elastic features formed from a first material or a first composition of materials and some hard features formed from a second material or a second composition of materials that are stiffer than the first material or the first composition of materials.
Furthermore, different mechanical properties may be selected for the elastic features and the hard features to achieve uniform polishing. The changes in the mechanical properties may be achieved by selecting different materials and/or choosing different curing processes. In one embodiment, the elastic features may have a lower hardness value and a lower value Young's modulus, while the hard features may have a higher hardness value and a higher value Young's modulus. In another embodiment, dynamic mechanical properties, such as storage modulus and loss modulus, may be used to design the elastic features and the hard features.
The hard features may be formed from polymer materials. The hard features may be formed from a single polymer material or a mixture of two or more polymers to achieve target properties. In one embodiment, the hard features may be formed from one or more thermoplastic polymers, such as polyurethane, polypropylene, polystyrene, polyacrylonitrile, polymethyle methacrylate, polychlorotrifluoroethylene, polytetrafluoroethylene, polyoxymethylene, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, polyether sulfone, acrylonitrile butadiene styrene (ABS), polyetherimide, polyamides, melamines, polyesters, polysulfones, polyvinyl acetates, fluorinated hydrocarbons, and the like, and mixtures, copolymers and grafts thereof. In another embodiment, the hard features may include one or more thermosetting polymers, such as epoxies, phenolics, amines, polysters, urethanes, silicon, and mixtures, copolymers, and grafts thereof. Furthermore, in one embodiment, abrasive particles may be embedded in the hard features to enhance polishing. The material comprising the abrasive particles may be a metal oxide, such as ceria, alumina, silica, or a combination thereof, a polymer, an inter-metallic or ceramic.
The elastic features may be formed from one or more polymer materials. The elastic features may be formed from a single polymer material or a mixture of two more polymers to achieve target properties. In one embodiment, the elastic features may be formed one or more of thermoplastic polymers. For example, the elastic features may be formed from thermoplastic polymers, such as polyurethane, polypropylene, polystyrene, polyacrylonitrile, polymethyle methacrylate, polychlorotrifluoroethylene, polytetrafluoroethylene, polyoxymethylene, polycarbonate, polyimide, polyetheretherketone, polyphenylene sulfide, polyether sulfone, acrylonitrile butadiene styrene (ABS), polyetherimide, polyamides, melamines, polyesters, polysulfones, polyvinyl acetates, fluorinated hydrocarbons, and the like, and mixtures, copolymers and grafts thereof. The elastic features 206 may be formed from thermoplastic elastomers. In one embodiment, the elastic features may be formed from a rubber-like 3D printing material.
The hard features are generally harder and more rigid than the elastic features while the elastic features are softer and more flexible than the hard features. Materials, patterns, and relative amounts of the hard features and the elastic features may be selected to achieve a “tuned” bulk material of the polishing pad. The polishing pad formed with this “tuned” bulk material has various advantages, such as improved polishing results, reduced cost of manufacturing, elongated pad life. In one embodiment, the “tuned” bulk material or the polishing pad as a whole may have hardness between about 65 shore A to about 75 shore D. Tensile strength of the polishing pad may be between 5 MPa to about 75 MPa. The polishing pad may have about 5% to about 350% elongation to bread. The polishing pad may have shear strength above about 10 mPa. The polishing pad may have storage modulus between about 5 MPa to about 2000 MPa. The polishing pad may have stable storage modules over temperature range 25° C. to 90° C. such that storage modulus ratio at E30/E90 falls within the range between about 6 to about 30, wherein E30 is the storage modulus at 30° C. and E90 is the storage modulus at 90° C. The hard features and elastic features may be used throughout the body of the polishing pad and/or the polishing layer of the polishing pad. The polishing pad 450 described above is one example of a polishing pad that may incorporate the hard features and elastic features. For example, the adjustable polishing features 471 may elastic features can extend past the fixed polishing features 472, which are the hard features.
FIG. 12A is a top sectional view of a polishing pad 1250 and associated equipment, according to one embodiment. FIG. 12B is a side sectional view of the polishing pad 1250 taken along the line 12B of FIG. 12A. Referring to FIGS. 12A and 12B, the polishing pad 1250 is similar to the polishing pad 750 of FIG. 7 except that the polishing pad 1250 includes a plurality of sectors 1210 disposed around a center 1257 of the polishing pad 1250. The polishing pad 1250 is shown including four sectors 1210, but more or less sectors may be included. The polishing pad 1250 includes a plurality of dividers 1214 to separate adjacent sectors. The different sectors 1210 can be used to control fluid delivery through different angular regions about the center 1257 of the polishing pad 1250 in the X-Y plane. In some embodiments, the sectors 1210 are symmetrically disposed around the center 1257 of the polishing pad 1250. For example, polishing pad 1250 shows four symmetrical sectors 1210 each covering an angular area of about 90 degrees of the polishing pad 1250 in the X-Y plane.
In some embodiments, the polishing pad 1250 can have a generally circular shape similar to the other polishing pads discussed above. Each sector 1210 of the polishing pad 1250 includes a plenum 1215 (also referred to as a channel) and a supply line 1216. Each plenum 1215 can extend around most of the angular area of the sector, such as at least 75% or at least 90% of the angular area of the sector. Each plenum can be 1215 disposed adjacent to a polishing surface 1274 of a given sector 1210, such as beneath the polishing surface 1274 of the sector 1210. Each sector 1210 of the polishing pad 1250 further includes polishing features 1271. Each polishing feature 1271 can include a polishing feature channel 1275. The polishing feature channel 1275 can be used along with the supply channel 1261 and plenum 1265 to deliver fluids to an aperture 1276 through the polishing surface 1274.
The supply plenum 1215 connects the supply line 1216 of a given sector 1210 to the polishing feature channels 1275 of that sector 1210, so that fluid may be delivered to the polishing surface 1274 of that sector 1210. Fluids delivered to the polishing surface 1274 through the polishing feature channel 1275 can include fluids, such as slurries, surfactants, pad cleaning chemistries, deionized water and other fluids. The fluids can be delivered through one or more conduits of a platen (not shown). The supply lines 1216 can each be connected to different ports 1218 on a surface of the polishing pad 1250, such as a bottom surface of a polishing pad 1250. Delivering fluids directly out of the polishing channel features ensures the fluid is provided between the substrate being polished and the polishing pad.
The different sectors 1210 can be used to control fluid delivery through the different angular regions of the polishing surface 1274 of the polishing pad 1250. For example, the fluid, such as a slurry, may be pulsed through the different sectors 1210 as the polishing pad 1250 rotates during polishing, so that more fluid is delivered through a given sector 1210 when the substrate being polished is contacting the polishing features 1271 of that sector 1210. In one embodiment, each supply line 1216 is connected to a separate valve 1281-1284, where each valve 1281-1284 is connected to a slurry supply and one or more pumps as needed. A controller, such as the controller 25 described above, may be used to open and close the valves 1281-1284. The opening and closing of the valves 1281-1284 can be synchronized with the rotation of the polishing pad 1250 on the platen (not shown), so that the fluid, such as a slurry, is pulsed through a given sector when the substrate being polished is contacting the polishing features 1271 of that sector 1210. In some embodiments, there are times when at least two valves (e.g., valves 1281, 1282) for adjacent sectors 1210 are opened during polishing, so that the sector 1210 that will contact the substrate next already has fluid, such as slurry, being supplied to the polishing surface 1274 of that next sector 1210 before that next sector 1210 rotates beneath the substrate.
By synchronizing the delivery of the slurry or other fluids to the location of the substrate during polishing, large amounts of slurry or other fluids may be saved. These savings can reduce the cost of production of the devices that are made using chemical mechanical polishing.
Many of the different features of the polishing pads discussed above can be combined with the features of the other polishing pads to create polishing pads having greater functionality. For example, one polishing pad can include features, such as pressurizable channels (e.g., channels 451-453) temperature control channels (e.g., channels 651-656), and slurry delivery channels (e.g., channels 851-853 and 875). In some embodiments, one channel can serve dual purposes. For example, pressurized cooling water may be applied to control pressure and temperature in one channel.
In some embodiments, the designs discussed above can be modified to create more symmetrical designs to provide better balancing of forces as the polishing pads are rotated by the platens during polishing. For example, the channel 461 of polishing pad 450 as shown in FIG. 4A can extend radially in two or more directions to pressurize the channels 451-453 and make the polishing pad 450 more symmetrical.
Although the polishing pads and many of the features of the polishing pads, such as the internal channels (e.g., inner channel 351) are described having circular geometries, the polishing pads and the features of the polishing pads may take other shapes, such as polygons or irregular shapes. For example, a polishing pad may have a polygonal shape, such as a rectangular shape. As another example, the plenum 355, inner channel 351, and outer channel 352 may all be formed in a rectangular or other shape. As another example, the internal channels of some polishing pads could take a spiral shape. For example, the polishing pad 550 may redesigned so that one channel spirals from the center towards the edges of the polishing pad, so that the heating or cooling fluid enters at the center and exits around the edges of the polishing pad.
Furthermore, other sensors besides the pressure and temperature sensors described above may be installed in the polishing pads. In one embodiment, a differential pressure sensor arrangement may be included in one of the polishing pads used for fluid delivery, such as the polishing pad 850. The differential pressure may be measured between the common supply channel 861 and each of the channels 851-853. For example, a high differential pressure measurement may indicate that one of the channels 851-853 is clogged or needs to be cleaned.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A polishing pad for chemical mechanical polishing comprising:

a base region having a supporting surface;

a plurality of polishing features forming a polishing surface, the polishing surface opposing the supporting surface; and

one or more channels formed in an interior region of the polishing pad, the one or more channels extending at least partly around a center of the polishing pad, wherein each channel is fluidly coupled to at least one port.

2. The polishing pad of claim 1, wherein:

the one or more ports comprises two or more ports; and

the one or more channels comprises two or more channels, wherein at least two of the channels are fluidly coupled to a separate port.

3. The polishing pad of claim 2, wherein the two or more channels comprise at least an inner channel and an outer channel, wherein the outer channel substantially surrounds the inner channel.

4. The polishing pad of claim 3, further comprising a pressure sensor disposed in at least one of the inner channel and the outer channel.

5. The polishing pad of claim 1, wherein:

the plurality of polishing features comprises fixed polishing features and adjustable polishing features; and

the one or more channels comprises two or more channels, wherein each channel is disposed adjacent to at least some of the adjustable polishing features.

6. The polishing pad of claim 1, wherein each channel is fluidly coupled to two or more ports.

7. The polishing pad of claim 6, wherein at least two of the channels are fluidly coupled to separate ports.

8. The polishing pad of claim 6, wherein each channel is fluidly coupled to a supply port and a return port, and each channel extends about 360 degrees around the center of the polishing pad.

9. The polishing pad of claim 6, further comprising a temperature sensor disposed in each channel.

10. The polishing pad of claim 1, wherein at least some of the polishing features comprise a polishing feature channel coupling one of the one or more channels to an aperture through the polishing surface.

11. The polishing pad of claim 10, further comprising a plurality of sectors disposed around a center of the polishing pad, wherein each sector includes one of the one or more channels and each channel is coupled to a separate port of the polishing pad.

12. The polishing pad of claim 10, further comprising a ring of polishing features that each have an aperture through the polishing surface surrounding a ring of polishing features that each lack an aperture through the polishing surface.

13. A polishing pad for chemical mechanical polishing comprising:

a base region having a supporting surface;

one or more plenums formed in an interior region of the polishing pad, wherein each of the one or more plenums is fluidly coupled to a port.

14. The polishing pad of claim 13, wherein at least some of the polishing features comprise a polishing feature channel coupling the plenum to an aperture in the polishing surface.

15. The polishing pad of claim 13, further comprising an inner channel and an outer channel, wherein the outer channel substantially surrounds the inner channel and the inner channel substantially surrounds one of the one or more plenums.

16. The polishing pad of claim 15, further comprising a pressure sensor disposed in each of the plenum, the inner channel and the outer channel.

17. The polishing pad of claim 15, wherein the plenum, the inner channel, and the outer channel are each coupled to a supply port and a return port and a temperature sensor is disposed in at least one of the plenum, the inner channel, and the outer channel.

18. The polishing device of claim 15, wherein the plenum, the inner channel and the outer channel are filled with a non-Newtonian fluid.

19. A polishing device for chemical mechanical polishing comprising:

a platen comprising:

a shaft;

a platen plate supported by the shaft, the platen plate having a mounting surface; and

one or more conduits distributed through the shaft and the platen plate;

a polishing pad comprising:

a base region having a supporting surface for contacting the mounting surface of the platen;

a plurality of polishing features forming a polishing surface, the polishing surface opposing the supporting surface;

one or more channels formed in an interior of the polishing pad, the one or more channels extending at least 15 degrees around a center of the polishing pad; and

a seal providing a sealed connection between the one or more conduits of the platen and the one or more channels of the polishing pad.

20. The polishing device of claim 19, wherein:

the one or more channels comprise two or more channels, and

the one or more conduits comprise two or more conduits, wherein at least two of the channels are fluidly coupled to a separate conduit.