Abstract:
In one embodiment, a method for cleaning a surface of a polishing pad includes conditioning the polishing pad surface and rotating the conditioned polishing pad surface. The method also includes spraying the polishing pad surface to lift debris from the conditioned polishing pad surface. The method further includes vacuuming the debris from the polishing pad surface downstream from where the condition occurs, wherein downstream is defined by a rotational direction of the polishing pad. In another embodiment, a processing station including a rotatable platen, a substrate carrier head, a polishing fluid delivery system, a conditioner, a spray nozzle, and a vacuum system is provided. The conditioner is disposed between the substrate carrier head and the spray nozzle. The vacuum system is configured to vacuum the polishing pad surface. The vacuum system is downstream from the conditioner, defined by a rotation of the platen.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 61/792,653, filed on Mar. 15, 2013, which herein is incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention generally relate to an apparatus for cleaning a polishing pad with a vacuum apparatus, and methods of using the same. Additionally, embodiments of the present invention also relate to a chemical mechanical planarization system for use with the vacuum apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    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 planarization (CMP) procedures are useful in removing undesired surface topography and surface defects, such as rough surfaces, agglomerated materials, crystal lattice damage, and scratches. The procedures are also useful in forming features on a substrate by removing excess deposited material used to fill the features and to provide an even or level surface for subsequent deposition and processing. A CMP process generally includes pressing a substrate against a polishing surface of a polishing pad in the presence of a polishing media, such as a polishing fluid or slurry. Relative motion is provided between the substrate and polishing surface to planarize the surface of the substrate in contact with the pad through one or a combination of a chemical, mechanical or electrochemical process. 
         [0006]    During polishing processes, the polishing surface of the pad that is in contact with a feature side of the substrate becomes laden with used polishing fluid and by-products from the various processes performed on the substrate (i.e., processing debris). The debris may create an unevenness in the plane of the polishing surface, as well as clogging or blocking pores present on the polishing surface, whereby reducing the ability of the pad to properly and efficiently planarize the substrate. Periodic conditioning of the polishing surface is required to maintain a consistent roughness, porosity and/or generally flat profile across the polishing surface. However, many current conditioning methods are designed to only condition the polishing surface and do not effectively remove particles or debris generated during processing, and or the conditioning process. 
         [0007]    Therefore, there is a need for an improved method and apparatus for cleaning a polishing pad. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the present invention generally relate to an apparatus for cleaning a polishing pad surface with a vacuum system, and methods of using the same. In one embodiment, a method for cleaning a surface of a polishing pad is provided. The method includes conditioning the polishing pad surface and rotating the conditioned polishing pad surface. The method also includes spraying the polishing pad surface to lift debris from the conditioned polishing pad surface. The method further includes vacuuming the debris from the polishing pad surface downstream from where the condition occurs, wherein downstream is defined by a rotational direction of the polishing pad. 
         [0009]    In another embodiment, a method for processing a substrate is provided. The method includes delivering a polishing fluid through a polishing fluid delivery arm to a surface of a polishing pad and rotating a portion of the polishing pad surface having the polishing fluid thereon. The method also includes polishing the substrate against the polishing pad surface in the presence of the polishing fluid and conditioning the polishing pad surface. The method further includes high-pressure spraying the polishing pad surface to lift debris from the polishing pad surface and vacuuming the debris. The vacuuming occurs downstream from where the conditioning occurs, wherein downstream is defined by a rotational direction of the polishing pad. 
         [0010]    In yet another embodiment, a processing station is provided. The processing station includes a rotatable platen, a substrate carrier head, a polishing fluid delivery system, a conditioner, a spray nozzle, and a vacuum system. The substrate carrier head is configured to retain a substrate against a surface of a polishing pad disposed on the platen. The polishing fluid delivery system is configured to provide polishing fluid to the polishing pad surface. The conditioner is disposed adjacent the platen and adapted to condition the polishing pad surface. The spray nozzle is configured to provide a high-pressure water spray to the polishing pad surface. The conditioner is disposed between the substrate carrier head and the spray nozzle. The vacuum system is configured to vacuum the polishing pad surface. The vacuum system is downstream from the conditioner, defined by a rotation of the platen. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    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. 
           [0012]      FIG. 1  is a top plan view of one embodiment of a processing station; 
           [0013]      FIG. 2  is a partial side view of a vacuum assembly having a polishing pad disposed below the vacuum assembly; 
           [0014]      FIG. 3  is a top plan view of one embodiment of a processing station; and 
           [0015]      FIG. 4  is a flow diagram of a method of polishing a substrate. 
       
    
    
       [0016]    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. 
       DETAILED DESCRIPTION 
       [0017]      FIG. 1  is a top plan view of the processing station  100  that is configured to perform a polishing process, such as a CMP or electrochemical mechanical planarization (ECMP) process, while also being configured to clean a polishing surface  102  of a polishing pad  104 . The processing station  100  may be a stand-alone unit or part of a larger processing system. Examples of a larger processing system that the processing station  100  may be utilized with include REFLEXION®, REFLEXION GT™, REFLEXION LK™, REFLEXION LK ECMP™, and MIRRA MESA® polishing systems, all available from Applied Materials, Inc., located in Santa Clara, Calif. It is contemplated that other processing stations may be adapted to benefit from the invention, including those from other equipment manufacturers. 
         [0018]    The processing station  100  includes a substrate carrier head  106  (shown in phantom), a platen  108 , a conditioning module  110 , and a polishing fluid delivery assembly  112  (such as a slurry delivery assembly). The platen  108 , the conditioning module  110  and the slurry delivery assembly  112  may be mounted to a base  114  of the processing station  100 . 
         [0019]    The platen  108  supports the polishing pad  104 . The platen  108  is rotated by a motor (not show) so that the polishing pad  104  is rotated relative to a substrate  116  retained in the substrate carrier head  106  during processing. As such, terms such as upstream, downstream, in front, behind, before and after are generally to be interpreted relative to the motion or detection of the platen  108  and the polishing pad  104  supported thereon, as appropriate. 
         [0020]    The substrate carrier head  106  is configured to retain the substrate  116  and controllably urge the substrate  116  against the polishing surface  102  of the polishing pad  104  during processing. The substrate carrier head  106  may also rotate the substrate  116  during processing. 
         [0021]    The conditioning module  110  is configured to condition the polishing pad  104  by opening the pores of the polishing pad  104 . The conditioning module  110  includes a conditioning disk  118  and a conditioning head  120 . The conditioning disk  118  may be a brush having bristles made of a polymer material or may have an abrasive surface comprising abrasive particles. In one embodiment, the conditioning disk  118  is a circular disk that contains abrasive particles such as diamonds. The conditioning head  120  is configured to retain the conditioning disk  118  and controllably urge the conditioning disk  118  against the polishing surface  102  of the polishing pad  104  during conditioning. 
         [0022]    The slurry delivery assembly  112  is configured to deliver a polishing media, such as a fluid or slurry, to the polishing pad  104  while the substrate  116  is polished on the polishing surface  102 . As on skilled in the art would understand, the polishing pad  104  may include any features that would retain the polishing media, e.g. pores and/or polishing pad grooves found in the polishing pad  104 . The slurry delivery assembly  112  includes a slurry delivery arm  122  which may be located in front of or behind the substrate carrier head  106 . The slurry delivery arm  122  includes one or more slurry nozzles  124  and one or more spray nozzles  126 . In the embodiment shown in  FIG. 1 , the slurry delivery arm  122  also includes a vacuum assembly  128  disposed in the slurry delivery arm. The slurry nozzles  124  are coupled to a polishing fluid source  130  by a delivery line  132  and configured to deliver a polishing fluid, such as slurry, to the polishing surface  102 . The spray nozzles  126  are coupled to a water or deionized water source  134  by a delivery line  136  and configured to deliver high-pressure water spray to the polishing surface  102  to lift the debris off of the polishing surface  102 . In one embodiment, the slurry nozzles  124  and the spray nozzles  126  are disposed in the slurry delivery arm  122 . The debris may comprise by-products from the various processes performed on the substrate and the condition process. In one embodiment, the slurry delivery arm  122  having the slurry nozzle  124 , the spray nozzle  126  and the vacuum assembly  128  are located in the same angular position (as shown in  FIG. 1 ). 
         [0023]      FIG. 2  is a partial sectional view of the vacuum assembly  128 . Referring to  FIGS. 1 and 2 , the vacuum assembly  128  includes a vacuum port  200  coupled to a vacuum source  138  by a delivery line  140 . The vacuum port  200  is configured to vacuum the polishing surface  102 , at an adjustable distance  202  between the vacuum port  200  and the polishing surface  102 . The vacuum assembly  128  is configured to remove debris from the polishing surface  102 . 
         [0024]    Referring back to  FIG. 1 , the slurry delivery arm  122  is adapted to move the nozzles  124 ,  126  and the vacuum assembly  128  from an edge of the polishing pad  104  diameter to at least a portion of the radius of the polishing pad  104  in a linear, arcing or sweeping motion. The movement of the arm  122  may be configured such that the entire surface of the polishing pad is vacuumed. 
         [0025]    Additionally, the location of the processing station  100  elements provides a beneficial order for conditioning and cleaning the polishing surface  102 . The substrate carrier head  106  is located directly downstream of the slurry delivery arm  122  and directly upstream of the conditioning module  110 . The slurry nozzles  124  of the slurry delivery arm  122  are located adjacent the substrate carrier head  106  to provide polishing media to the polishing surface  102  just upstream of the substrate  116  prior to polishing. Similarly, the conditioning module  110  is beneficially located downstream of the substrate carrier head  106  to condition the polishing surface  102  immediately after the substrate has been polished on the polishing surface  102 , and located between the substrate carrier head  106  and the spray nozzles  126 . The spray nozzles  126  are located downstream of the conditioning module  110 , and located between the conditioning module  110  and the vacuum assembly  128 . The vacuum assembly  128  is located downstream of the spray nozzles  126 , and located between the slurry nozzles  124  and the spray nozzles  126 . The spray nozzles  126  provide a jet of high pressure water to the conditioned polishing surface  102  which lifts debris from the polishing surface  102  after the polishing pad  104  has been conditioned, and thus allows for the vacuum assembly  128  to immediately remove debris from the polishing pad  104  prior to delivery of additional polishing media thereto. Since the spray nozzles  126  are located between the conditioning module  110  and the vacuum assembly  128 , any abrasives coming loose from the conditioning module  110  and embedded into the polishing pad  104  may be loosened and dislodged from the pad  104  by the high pressure jets prior to vacuuming, thereby allowing the vacuum assembly  128  to make more efficient removal of debris from the pad  104 . In contrast, conventional system having vacuums proximate the conditioning module and upstream of any high pressure water sprays systems do not effectively remove hard to remove debris from the pad since the pad has been vacuumed prior to debris effectively being dislodged from the pad surface. 
         [0026]      FIG. 3  is a top plan view of another embodiment of the processing station  100  that is configured to perform a polishing process, such as a CMP or electrochemical mechanical planarization (ECMP) process. In the embodiment shown in  FIG. 3 , the processing station  100  includes a stand-alone vacuum assembly  300  configured to remove debris from the polishing surface  102 . The stand-alone vacuum assembly  300  includes a vacuum delivery head  302  and one or more spray nozzles  304 . The vacuum delivery head  302  includes the vacuum port  200  (shown in  FIG. 2 ) coupled to a vacuum source  306  by a delivery line  308 . The one or more spray nozzles  304  are coupled to a high-pressure water or deionized water source  310  by a delivery line  312 , and the spray nozzles  304  are configured to spray the polishing pad surface  102  to lift the debris off the polishing surface  102 . The conditioning module  110  is disposed between the substrate carrier head  106  and the vacuum assembly  300 . The vacuum assembly  300  is configured to remove the debris from the polishing surface  102  by vacuuming the polishing surface  102 . Additionally the vacuum assembly  300  is adapted to move the vacuum delivery head  302  and the nozzles  304  from an edge of the polishing pad  104  to at least a portion of the radius of the polishing pad  104  in a linear, arcing or sweeping motion, as discussed above 
         [0027]    As discussed above, the location of the processing station  100  elements provides a beneficial order for conditioning and cleaning the polishing surface  102 . Specifically, the vacuum delivery head  302  is advantageously located downstream of the spray nozzles  126 , which are downstream of the conditioning module  110 , thereby allow more efficient removal of debris from the polishing pad  104 . Locating the vacuum delivery head  302  within the slurry delivery arm  122  minimizes the number of modules present on the processing station  100 , thereby providing a cost effective solution to pad cleaning while preparing a cleaned polishing surface  102  for the next substrate to be polished. 
         [0028]      FIG. 4  is a flow diagram of a method  400  for polishing substrates. It should be noted that the sequence of the method discussed below is not intended to be limiting as to the scope of the invention described herein, since one or more elements of the sequence may be added, deleted and/or reordered without deviating from the basic scope of the invention. 
         [0029]    At block  402  the method may begin by providing polishing media, such as slurry, through the slurry nozzles  124  of the slurry delivery arm  122  to the polishing surface  102  at a location downstream of the vacuum assembly  128 , relative to the rotation of the polishing pad  104 . The location is defined a region between the vacuum assembly and the substrate carrier head  106 . At block  404 , the substrate carrier head  106  urges the substrate  116  towards the polishing surface  102  to be polished in the presence of the slurry. At block  406 , the conditioning module  110  then conditions the polishing surface  102  of the polishing pad  104  as discussed above, or by other suitable conditioning techniques. 
         [0030]    At block  408 , water is sprayed at a high-pressure to the polishing surface  102  through the spray nozzles  126  or spray nozzles  304 . In one embodiment, the water is sprayed at a location upstream of the vacuum assembly  128  or vacuum assembly  300 , relative to the rotation of the polishing pad  104 . The location is defined as a region between the conditioning module  110  and the substrate carrier head  106 , relative to the rotation of the polishing pad. Advantageously, the high-pressure water loosens and lifts the particles and debris present on the polishing surface. The polishing surface  102  is vacuumed through the vacuum assembly  128  or the vacuum assembly  300  to remove the recent water containing the lifted debris from the polishing surface  102 . The polishing surface  102  is vacuumed at a location downstream of the conditioning module  110  and the spray nozzles  126  or spray nozzles  304 , relative to the rotation of the polishing pad  104 . In one embodiment, the location is defined as a region between the spray nozzles  126  and the substrate carrier head  106 , the spray nozzles  304  and the substrate carrier head  106 . In another embodiment, the location is defined as a region between the slurry nozzles  124  and the spray nozzles  126 , or between the slurry nozzles  124  and the spray nozzles  304 . In one embodiment, the vacuuming may be performed prior to or after polishing the substrate  116 . However, in other embodiments, polishing and/or conditioning processes in the processing stations  100  or  300  are stopped or halted while the high-pressure water spray and the vacuum is applied to the polishing surface. Close proximity of the vacuum assembly  128 ,  300  to the spray nozzles  126  provides for quick and efficient and cleaning of the polishing surface  102 , and therefore reduces the associated polishing downtime. Additionally, the conditioning module is upstream of the high-pressure spray nozzles and the vacuum assemblies. This beneficially prevents costly slurry from being inadvertently treated as debris and vacuumed from the polishing surface  102 . 
         [0031]    Thus, the polishing surface  102  is advantageously removed of particles and debris from polishing processes and subsequent polishing of substrates is enhanced. While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.