1. Field of the Invention
Embodiments of the present invention generally relate to polishing a substrate, such as a semiconductor wafer.
2. Description of the Related Art
In the fabrication of integrated circuits and other electronic devices on substrates, multiple layers of conductive, semiconductive, and dielectric materials are deposited on or removed from a feature side, i.e., a deposit receiving surface, of a substrate. As layers of materials are sequentially deposited and removed, the feature side of the substrate may become non-planar and require planarization and/or polishing. Planarization and polishing are procedures where previously deposited material is removed from the feature side of the substrate to form a generally even, planar or level surface.
Chemical mechanical polishing is one process commonly used in the manufacture of high-density integrated circuits to planarize or polish a layer of material deposited on a semiconductor wafer by moving the feature side of the substrate in contact with a polishing pad while in the presence of a polishing fluid. Material is removed from the feature side of the substrate that is in contact with the polishing surface through a combination of chemical and mechanical activity.
Periodic conditioning of the polishing surface is required to maintain a consistent roughness across the polishing surface to facilitate enhanced material removal. The conditioning is typically performed using a rotating conditioning disk that is urged against the polishing surface. The conditioning disk is coupled to a support member that moves the conditioning disk in a sweeping pattern relative to the polishing surface. Providing a specific and/or consistent sweep pattern across the polishing surfaces creates challenges during conditioning that may result non-uniform roughness of the polishing surface. The non-uniform roughness may decrease material removal, which results in decreased throughput.
Therefore, there is a need for a method and apparatus that facilitates selective and/or consistent conditioning of the polishing surface.
The present invention generally provides an apparatus and method for conditioning a polishing pad using linear motion. In one embodiment, an apparatus for conditioning a polishing pad is described. The apparatus includes a base coupled to a platform, a first arm member having a first end coupled to the base and an opposing second end, a second arm member having a first end pivotably coupled to a second end of the first arm member, and a conditioning disk coupled to a second end of the second arm member opposite the first end of the first arm member.
In another embodiment, a method of conditioning a polishing pad is described. The method includes rotating a polishing pad, urging a rotating conditioning disk against a polishing surface of the polishing pad, and moving the conditioning disk in a linear direction relative to the rotating polishing pad to perform a conditioning process.
In another embodiment, an apparatus for conditioning a polishing pad is described. The apparatus includes a base coupled to a platform, a first arm member coupled to the base, a second arm member coupled to the first arm member, a conditioning disk coupled to the second arm member opposite the base, and a joint member coupled between the first arm member and the second arm member, the joint member adapted to provide rotation of the first arm member relative to the second arm member.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, 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 invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals 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.
Embodiments of the present invention generally provide a method and apparatus for conditioning a polishing surface of a polishing pad. A conditioning device having a linearly extendable arm configuration is described for use on a polishing pad having a circular configuration. Although not shown, embodiments of the conditioning device may be used on polishing pads having other shapes, such as rectangular polishing pads or belt-type polishing pads.
The overhead track 128 allows each carriage 108 to be selectively positioned around the polishing module 106. The configuration of the overhead track 128 and carriages 108 facilitates positioning of the polishing heads 126 selectively over the polishing stations 124 and the load cups 122. In the embodiment depicted in
Referring now primarily to
Each polishing station 124 generally includes a polishing surface 130, a conditioning module 132 and a polishing fluid delivery module 134. The polishing surface 130 is supported on a platen assembly (not shown in
The polishing surface 130 is configured, in one embodiment, to accommodate polishing of at least two substrates simultaneously thereon. In such an embodiment, the polishing station 124 includes two conditioning modules 132 and two polishing fluid delivery modules 134 which condition and provide polishing fluid to the region of the polishing surface 130 just prior to interfacing with a respective substrate 170. Additionally, each of the polishing fluid delivery modules 134 are positioned to provide independently a predetermined distribution of polishing fluid on the polishing surface 130 so that a specific distribution of polishing fluid is respectively interfaced with each substrate during processing.
In one embodiment, the overhead track 128 is coupled to the frame member 204 while the polishing stations 124 are coupled to a polishing station platform 202. In this embodiment, each polishing station 124 can be provided as a stand-alone unit or a plurality of polishing stations 124 may be coupled together with the platform 202. In one embodiment, the polishing station platform 202 and frame member 204 are coupled to a floor 200 of the facility without being connected to each other. The decoupled polishing station platform 202 and frame member 204 allows vibrations associated with the movement of the carriages 108 to be substantially isolated from the polishing surface 130, thereby minimizing potential impact to polishing results. Moreover, utilization of the polishing station platform 202 without a machine platform provides significant cost savings over conventional designs.
The polishing head 126 is coupled to the carriage 108 by a shaft 232. A motor 234 is coupled to the carriage 108 and is arranged to controllably rotate the shaft 232, thereby rotating the polishing head 126 and a substrate 201 disposed therein during processing. At least one of the polishing head 126 or carriage 108 includes an actuator (not shown) for controlling the elevation of the polishing head 126 relative to the polishing surface 130. In one embodiment, the actuator allows the polishing head 126 to be pressed against the polishing surface 130 at about 6 psi or less, such as less than about 1.5 psi.
A platen assembly 200 supports a polishing pad 218 that may be made entirely of a dielectric material or include conductive material disposed in a dielectric material. The upper surface of the pad 218 forms the polishing surface 130. The platen assembly 200 is supported on the polishing station platform 202 by one or more bearings 214. The platen 216 is coupled by a shaft 206 to a motor 208 that is utilized to rotate the platen assembly 200. The motor 208 may be coupled by a bracket 210 to the polishing station platform 202. In one embodiment, the motor 208 is a direct drive motor. It is contemplated that other motors may be utilized to rotate the shaft 206. In the embodiment depicted in
During processing or when otherwise desired, the conditioning module 132 is activated to contact and condition the polishing surface 130. Additionally, polishing fluid is delivered through the polishing fluid delivery module 134 to the polishing surface 130 during processing and/or conditioning. The distribution of fluid provided by the polishing fluid delivery arm 132 may be selected to control the distribution of polishing fluid across the lateral surface of the polishing surface 130. It should be noted that only one polishing head 126, conditioning module 132 and polishing fluid delivery module 134 are depicted in
The conditioning arm assembly 304 includes at least two articulatable arms or links, such as a first arm member 330A and a second arm member 330B. The conditioning arm assembly 304 also includes at least one pivot point or joint 332 coupling the first and second arm member 330A, 330B providing relative movement between the arm members 330A, 330B. A second motor 320 is utilized to move the first arm member 330A relative to the second arm member 330B. The second motor 320 is coupled to a transmission system 325 that, in one embodiment, includes a shaft 322 (shown in phantom) which is coupled to a drive member 309, which in turn are coupled to one or more transmission members 326, which may be belts, wires, or cables. In one embodiment, the transmission members 326, such as belts are coupled to drive members 309 and the shaft 322 to facilitate movement of the first arm member 330A relative to the second arm member 330B such that angular changes are provided between the first arm member 330A and the second arm member 330B.
Each of the drive members 309 may be a pulley or gear adapted to transfer rotational or translation motion from one element to another. The term “gear” as used herein is intended to generally describe a component that is rotationally coupled to a transmission member 326, such as a belt, teeth, wires, cables, and is adapted to transmit motion from one element to another. In general, a gear, as used herein, may be a conventional gear type device or pulley type device, which may include but is not limited to components such as, a spur gear, bevel gear, rack and/or pinion, worm gear, a sheave, a timing pulley, and a v-belt pulley. The joint 332 may be a revolute joint, a screw joint, or other joint having one or more degrees of freedom.
In one embodiment, the elevation of the conditioning arm assembly 304 may be controlled by a vertical actuator 318. In one embodiment, the actuator 318 is coupled to a guide 314 that is coupled to the base 302. The guide 314 may be positioned along a rail 316 which is coupled to the polishing station platform 202 so that the actuator 318 may control the elevation of the conditioning arm assembly 304 and the conditioning head 306. A collar 324 is provided to prevent liquid from passing between the base 302 and an upper surface 310 of the polishing station platform 220.
In one aspect, the first transmission system 325 includes a transmission ratio (e.g., ratio of diameters, ratio of the number of gear teeth) of the first drive system 351A and second drive system 351B that is designed to achieve a desired shape and resolution of an actuation or extension path (e.g., element 450A and/or 450B in
In one embodiment, a second transmission system 360 is provided on the conditioning arm assembly 304 that may be utilized along with the first transmission system 325. In this embodiment, the second transmission system 360 is configured to rotate the conditioning head 306 about a center axis. The second transmission system 360 includes a first gear 362A coupled to a second motor 356B by a shaft 361. The first gear 362A is coupled to a second gear 362B and third gear 362C by a transmission member 363A. Rotational movement from the second motor 356B is transmitted to the second gear 362B and third gear 362C by the transmission member 363A. A second transmission member 363B is coupled between the third gear 362C and a fourth gear 362D and fifth gear 362E to transmit rotational movement from the second motor 356B to the fifth gear 362E. A sixth gear 362F is rotationally coupled to the fifth gear 362E by a third transmission member 363C. The sixth gear 362F is coupled to a shaft 364 that is coupled to the conditioning head 306. Thus, rotational movement of the second motor 356B is transmitted to the conditioning head 306 through the conditioning arm assembly 304. While not shown, bearings and/or seals for each of the gears and shafts may be provided. In one aspect, one or both of the first motor 356A and second motor 356B is a stepper motor or DC servomotor. A flexible sleeve or cover 350 may be coupled to the conditioning arm assembly 304 at the joint 332 to contain any particles that may be generated at the joint 332.
In
In
The first arm member 330A is movably coupled by first joint 532A to the base 302 to rotate the first arm member 330A relative to the base 302. The second joint 532B is configured to pivotally couple the first arm member 330A to the second arm member 330B. In one embodiment, the first joint 532A may be coupled to the first transmission system 325 of
The embodiments of the conditioning arm assemblies 304, 404 and 504 as described above provide a more accurate and controllable sweep pattern as compared to other conditioning apparatus. The configuration of the conditioning arm assemblies 304, 404 and 504 use less space on a polishing module 100 which allows additional space for polishing heads, fluid delivery modules and other hardware used in or on the polishing module 100. For example, the movement configurations of the first arm member 330A and the second arm member 330B may be varied based on allocated space on the polishing module 100. Factors such as height allowances, width allowances, and other dimensional constraints between other hardware disposed on the polishing module 100 may be considered and the conditioning arm assemblies 304, 404 and 504 may be configured accordingly.
Additionally, the configuration of the conditioning arm assemblies 304, 404 and 504 provides alternative sweep patterns to perform a conditioning process.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application claims benefit of U.S. provisional patent application Ser. No. 61/117,536, filed Nov. 24, 2008, which is herein incorporated by reference.
Number | Date | Country | |
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61117536 | Nov 2008 | US |