| Apparatus and method for conditioning a polishing pad used for mechanical and/or chemical-mechanical planarization -> Monitor Keywords |
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  Apparatus and method for conditioning a polishing pad used for mechanical and/or chemical-mechanical planarizationRelated Patent Categories: Abrading, Precision Device Or Process - Or With Condition Responsive Control, Computer ControlledThe Patent Description & Claims data below is from USPTO Patent Application 20060199472. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] The present invention relates to an apparatus and method for conditioning a polishing pad used for mechanical and/or chemical-mechanical planarization of micro-device workpieces. BACKGROUND [0002] Mechanical and chemical-mechanical planarization processes (collectively "CMP") remove material from the surface of micro-device workpieces in the production of microelectronic devices and other products. FIG. 1 schematically illustrates a rotary CMP machine 10 with a platen 20, a carrier head 30, and a planarizing pad 40. The CMP machine 10 may also have an under-pad 25 between an upper surface 22 of the platen 20 and a lower surface of the planarizing pad 40. A drive assembly 26 rotates the platen 20 (indicated by arrow F) and/or reciprocates the platen 20 back and forth (indicated by arrow G). Since the planarizing pad 40 is attached to the under-pad 25, the planarizing pad 40 moves with the platen 20 during planarization. [0003] The carrier head 30 has a lower surface 32 to which a micro-device workpiece 12 may be attached, or the workpiece 12 may be attached to a resilient pad 34 under the lower surface 32. The carrier head 30 may be a weighted, free-floating wafer carrier, or an actuator assembly 36 may be attached to the carrier head 30 to impart rotational motion to the micro-device workpiece 12 (indicated by arrow J) and/or reciprocate the workpiece 12 back and forth (indicated by arrow 1). [0004] The planarizing pad 40 and a planarizing solution 44 define a planarizing medium that mechanically and/or chemically-mechanically removes material from the surface of the micro-device workpiece 12. The planarizing solution 44 may be a conventional CMP slurry with abrasive particles and chemicals that etch and/or oxidize the surface of the micro-device workpiece 12, or the planarizing solution 44 may be a "clean" nonabrasive planarizing solution without abrasive particles. In most CMP applications, abrasive slurries with abrasive particles are used on nonabrasive polishing pads, and clean nonabrasive solutions without abrasive particles are used on fixed-abrasive polishing pads. [0005] To planarize the micro-device workpiece 12 with the CMP machine 10, the carrier head 30 presses the workpiece 12 face-down against the planarizing pad 40. More specifically, the carrier head 30 generally presses the micro-device workpiece 12 against the planarizing solution 44 on a planarizing surface 42 of the planarizing pad 40, and the platen 20 and/or the carrier head 30 moves to rub the workpiece 12 against the planarizing surface 42. As the micro-device workpiece 12 rubs against the planarizing surface 42, the planarizing medium removes material from the face of the workpiece 12. [0006] The CMP process must consistently and accurately produce a uniformly planar surface on the micro-device workpiece 12 to enable precise fabrication of circuits and photo-patterns. One problem with conventional CMP methods is that the planarizing surface 42 of the planarizing pad 40 can wear unevenly or become glazed with accumulations of planarizing solution 44 and/or material removed from the micro-device workpiece 12 and/or planarizing pad 40. To restore the planarizing characteristics of the planarizing pad 40, the pad 40 is typically conditioned by removing the accumulations of waste matter with an abrasive conditioning disk 50. The conventional abrasive conditioning disk 50 is generally embedded with diamond particles and mounted to a separate actuator 55 that moves the conditioning disk 50 rotationally, laterally, and/or axially, as indicated by arrows A, B, and C, respectively. The typical conditioning disk 50 removes a thin layer of the planarizing pad material in addition to the waste matter to form a new, clean planarizing surface 42 on the planarizing pad 40. [0007] During the conditioning process, the conditioning disk 50 imparts texture to the planarizing pad 40. One problem with conventional conditioning methods is that even if the conditioning disk 50 uniformly removes the planarizing pad material, different textures are formed across the planarizing pad 40. Differences in texture across the planarizing pad 40 can cause the pad 40 to remove material at different rates across the micro-device workpiece 12 during the CMP process. Differences in texture can also produce defects on the micro-device workpiece 12. Consequently, the CMP process may not produce a uniformly planar surface on the micro-device workpiece 12. SUMMARY [0008] The present invention is directed toward conditioning apparatuses and methods for conditioning polishing pads used for mechanical and/or chemical-mechanical planarization of micro-device workpieces. In one embodiment, a method for conditioning a polishing pad includes determining surface condition in a first region of the polishing pad, determining surface condition in a second region of the polishing pad, and adjusting at least one of a relative velocity between the polishing pad and an end effector, an existing downforce on the polishing pad, and a sweep velocity of the end effector in response to the determined surface condition of the first region to provide a desired first surface texture in the first region. The method further includes adjusting at least one of the relative velocity between the polishing pad and the end effector, the existing downforce on the polishing pad, and the sweep velocity of the end effector in response to the determined surface condition of the second region to provide a desired second surface texture in the second region. In a further aspect of this embodiment, determining surface condition can include sensing surface texture, roughness, and/or asperities. In another aspect of this embodiment, determining surface condition can occur while the polishing pad is in-situ, rotating, and/or stationary. [0009] In another embodiment of the invention, a method for conditioning the polishing pad includes monitoring surface condition in the first region of the polishing pad and adjusting at least one of a rotational velocity of the polishing pad, the downforce on the polishing pad, and the sweep velocity of the end effector in response to the monitored surface condition to provide the desired texture in the first region. [0010] In another embodiment of the invention, an apparatus for conditioning the polishing pad includes an end effector, a monitoring device, and a controller operatively coupled to the end effector and the monitoring device. In one aspect of this embodiment, the controller has a computer-readable medium containing instructions to perform a method including determining surface condition in the first region of the polishing pad, determining surface condition in the second region of the polishing pad, and adjusting at least one of the relative velocity between the polishing pad and the end effector, the existing downforce on the polishing pad, and the sweep velocity of the end effector in response to the determined surface condition of the first region to provide the desired first surface texture in the first region. The method further includes adjusting at least one of the relative velocity between the polishing pad and the end effector, the existing downforce on the polishing pad, and the sweep velocity of the end effector in response to the determined surface condition of the second region to provide a desired second surface texture in the second region. [0011] In another aspect of this embodiment, the controller has a computer-readable medium containing instructions to perform a method including monitoring surface condition in the first region of the polishing pad, and adjusting at least one of the rotational velocity of the polishing pad, the downforce on the polishing pad, and the sweep velocity of the end effector in response to the monitored surface condition to provide the desired texture in the first region. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a schematic cross-sectional view of a portion of a rotary planarizing machine and an abrasive conditioning disk in accordance with the prior art. [0013] FIG. 2 is a schematic isometric view of a portion of a rotary planarizing machine and a conditioning system in accordance with one embodiment of the invention. [0014] FIG. 3 is a side schematic view of the planarizing pad before conditioning. [0015] FIG. 4 is a schematic view of a conditioning system with a monitoring device in accordance with another embodiment of the invention. DETAILED DESCRIPTION [0016] The present invention is directed to apparatuses and methods for conditioning polishing pads used for mechanical and/or chemical-mechanical planarization of micro-device workpieces. The term "micro-device workpiece" is used throughout to include substrates in and/or on which micro-electronic devices, micro-mechanical devices, data storage elements, and other features are fabricated. For example, micro-device workpieces can be semi-conductor wafers, glass substrates, insulated substrates, or many other types of substrates. Furthermore, the terms "planarization" and "planarizing" mean either forming a planar surface and/or forming a smooth surface (e.g., "polishing"). Several specific details of the invention are set forth in the following description and in FIGS. 2-4 to provide a thorough understanding of certain embodiments of the invention. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that other embodiments of the invention may be practiced without several of the specific features explained in the following description. [0017] FIG. 2 is a schematic isometric view of a conditioning system 100 in accordance with one embodiment of the invention. The conditioning system 100 can be coupled to a CMP machine 110 to refurbish a planarizing pad 140 or to bring a planarizing surface 142 of the planarizing pad 140 to a desired state for consistent planarizing. The CMP machine 110 can be similar to the CMP machine 10 discussed above. For example, the CMP machine 110 can include a carrier head 130 coupled to an actuator assembly 136 to move the workpiece (not shown) across the planarizing surface 142 of the planarizing pad 140. [0018] In the illustrated embodiment, the conditioning system 100 includes a monitoring device 160, a controller 170, and an end effector 180. The end effector 180 can include an arm 182 and a conditioning disk 150 coupled to the arm 182 to exert a downforce F.sub.D against the planarizing pad 140. The conditioning disk 150 is generally imbedded with diamond particles to remove waste matter and a thin layer of the planarizing pad 140. The conditioning disk 150 forms a new clean planarizing surface 142 on the planarizing pad 140. The conditioning disk 150 rotates (indicated by arrow A) with a rotational velocity .omega..sub.1 to abrade the planarizing pad 140 with the diamond particles. In the illustrated embodiment, the arm 182 can sweep the conditioning disk 150 across the planarizing surface 142 in a direction S with a sweep velocity S.sub.V. The sweep velocity S.sub.V can change as the conditioning disk 150 moves across the planarizing surface 142 so that the disk 150 contacts different areas on the planarizing surface 142 for different dwell times. In the illustrated embodiment, the conditioning disk 150 conditions the planarizing pad 140 in-situ and in real-time with the planarization process. In other embodiments, conditioning and planarization may not occur concurrently. [0019] The monitoring device 160 monitors the surface condition of the planarizing surface 142. For example, the monitoring device 160 can determine the surface texture, roughness, and/or asperities of the planarizing surface 142. The monitoring device 160 can be stationary or movable relative to the CMP machine 110 to monitor the entire planarizing surface 142 of the planarizing pad 140 when the pad 140 is stationary or while it rotates. In one embodiment, the monitoring device 160 can include an optical analyzer, such as an interferometer or a device that measures the scatter of light. In other embodiments, the monitoring device 160 can use contact methods, such as frictional forces, or profilometry to monitor the surface condition. In any of these embodiments, the monitoring device 160 can monitor a single region or a plurality of monitoring devices can monitor multiple regions on the planarizing pad 140 concurrently. For example, the planarizing surface 142 of the planarizing pad 140 can be analyzed by organizing the pad 140 into known regions, such as a first region R.sub.1, a second region R.sub.2, and a third region R.sub.3. The monitoring device 160 can monitor the surface condition in the first, second, and third regions R.sub.1, R.sub.2, and R.sub.3 simultaneously. In other embodiments, the monitoring device 160 may monitor only one region at a time. In still other embodiments, a single monitoring device could be movable to monitor more than one region. Continue reading... Full patent description for Apparatus and method for conditioning a polishing pad used for mechanical and/or chemical-mechanical planarization Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Apparatus and method for conditioning a polishing pad used for mechanical and/or chemical-mechanical planarization patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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