Abstract:
A substrate holding and transporting assembly is disclosed. The substrate holding and transporting assembly includes a base plate and a pair of clamps connected to the base plate in a spaced apart orientation, the spaced apart orientation of the pair of clamps enable support of a substrate with at least two independent points. The substrate holding and transporting assembly also includes an electrode assembly connected to the base plate at a location that is substantially between the pair of clamps. The electrode assembly defined to impart an electrical contact to the substrate when present and held by the pair of clamps.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is related to application Ser. No. 11/539,611, entitled, P ROXIMITY PROCESSING USING CONTROLLED BATCH VOLUME WITH AN INTEGRATED PROXIMITY HEAD , filed on Oct. 6, 2006, which is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to handling of substrates and more specifically, the simultaneous movement of substrates through process heads while applying an electrical contact. 
         [0004]    2. Description of the Related Art 
         [0005]    Semiconductor substrate processing may include various process operations including, but not limited to, etching, deposition, cleaning and polishing. One method to perform a deposition process is to use electroplating. The electroplating process requires electrical contact to be made with the substrate as it is exposed to an electroplating process fluid. Various methods can be used to perform electroplating however it can be difficult to achieve consistent plating over the entire substrate because the electrical contact can interfere with the plating process. For example, one method of electroplating submerges a substrate in a tank of electroplating fluid. Electrical contact can be made with the substrate using a plurality of electrical contacts submerged in the tank. However, irregularities in the deposition of plating material can occur wherever electrical contact is made with the substrate. 
         [0006]    In view of the forgoing, there is a need for improved substrate handling that can provide highly reliable electrical contact in an electroplating environment while minimizing irregularities in the deposition of plating material. 
       SUMMARY 
       [0007]    In one embodiment, a substrate holding and transporting assembly is disclosed. The substrate holding and transporting assembly includes a base plate and a pair of clamps connected to the base plate in a spaced apart orientation. The spaced apart orientation can be defined to enable support of a substrate with at least two independent points, the two independent points defined by the pair of clamps. The substrate holding and transporting assembly also includes an electrode assembly being connected to the base plate at a location that is substantially between the pair of clamps. The electrode assembly defined to impart an electrical contact to the substrate when present and held by the pair of clamps. 
         [0008]    In another embodiment, a method for clamping and applying an electrical contact to a substrate is disclosed. The method includes providing a clamping assembly having an integrated electrode assembly in a receiving position capable of being independently actuated into a closed position. The clamping assembly also has at least two substrate clamps in a receiving position, the substrate clamps capable of being independently actuated into a clamped position. In another operation, the method receives the substrate at the clamping assembly and actuates the substrate clamps into the clamped position. The clamped position placing the substrate clamps in contact with the substrate. In another operation, the electrode assembly is actuated into a closed positioned, the closed position of the electrode assembly placing a plurality of electrodes in contact with the substrate. Wherein the plurality of electrodes that are in contact with the substrate apply the electrical contact. 
         [0009]    In yet another embodiment, a substrate handling assembly is disclosed. The substrate handling assembly includes, a base plate and a first substrate clamp coupled to the base plate. The first substrate clamps has a clamping face configured to hold and accommodate a substrate, when provided. The first substrate clamp also has an open position and a closed position, the closed position being defined to secure the substrate. The substrate handling assembly also includes a second substrate clamp coupled to the base plate also having a clamping face configured to hold and accommodate a substrate, when provided. The second substrate clamp spaced apart by a clamping distance from the first substrate clamp along the base plate to define support for the substrate. The second substrate clamp having an open position and a closed position, the closed position being defined to secure the substrate. The substrate handling assembly also includes an electrode assembly connected to the base plate at a location that is substantially between the first and second substrate clamps. The electrode assembly having a plurality of electrodes that have an open position and a closed position. The closed position being defined to transition the plurality of electrodes toward the base plate and in contact with the substrate when present. 
         [0010]    Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings. 
           [0012]      FIG. 1  is a high level schematic of a process module  102  in accordance with one embodiment of the present invention. 
           [0013]      FIG. 2  is a overview schematic of a gripper assembly in relation to a process station and substrate, in accordance with one embodiment of the present invention. 
           [0014]      FIG. 3  is a schematic illustrating a close up view of a gripper assembly in accordance with one embodiment of the present invention. 
           [0015]      FIG. 4  is an exploded view of the gripper assembly in accordance with one embodiment of the present invention. 
           [0016]      FIG. 5  and  FIG. 6  are schematics of substrate clamps  402  and  404  in accordance with embodiments of the present invention. 
           [0017]      FIG. 7  is an illustration of a contact lever in accordance with one embodiment of the present invention. 
           [0018]      FIG. 8  is an illustration of the electrode manifold assembly in accordance with one embodiment of the present invention. 
           [0019]      FIG. 8A  is an illustration of the electrode manifold, in accordance with one embodiment of the present invention. 
           [0020]      FIG. 8B  is an illustration of an electrode arm  804  in accordance with one embodiment of the present invention. 
           [0021]      FIG. 8C  is an exemplary schematic of an electrode diffuser in accordance with one embodiment of the present invention. 
           [0022]      FIG. 9  is a schematic illustrating a side view of a substrate clamp assembly installed in a gripper assembly in accordance with one embodiment of the present invention. 
           [0023]      FIG. 10  is a schematic illustrating a side of an electrode assembly installed in a gripper assembly in accordance with one embodiment of the present invention. 
           [0024]      FIG. 11A  and  FIG. 11B  are schematics illustrating various clamping distances, and comparative deflections of the substrate, in accordance with embodiments of the present invention. 
           [0025]      FIG. 12A  and  FIG. 12B  are schematic illustrations of a transport system for moving the gripper assemblies in accordance with one embodiment of the present invention. 
           [0026]      FIG. 13  is a flow chart illustrating a procedure that transport a substrate through a processing assembly in accordance with one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    An invention is disclosed for holding and transporting a substrate. The holding and transporting of substrates can affect the rate and yield of a given semiconductor substrate process. The ability to hold and transport a substrate with minimal interference with a variety of processes applied using proximity heads can reduce potential sources of contamination thereby increasing yields. Furthermore, process rates can be increased by integrating multiple processes such as plating and cleaning within a single proximity head. However, it can be difficult to integrate a cleaning process if a substrate transport device is in constant contact with the substrate. 
         [0028]    One embodiment of a holding and transport system for a substrate uses two grippers to hold and move the substrate into a proximity head. Initially in this embodiment, a first gripper picks up the substrate in an exclusion zone along the edge of the substrate. The first gripper transports the substrate into the proximity head and only the substrate is exposed to the process chemistry. As the substrate emerges from the proximity head, a second gripper is in position to receive the now processed substrate. In one embodiment, a handoff of the substrate between the first gripper and second gripper occurs after the second gripper clamps down on the substrate. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention. 
         [0029]      FIG. 1  is a high level schematic of a process module  102  in accordance with one embodiment of the present invention. In this embodiment, the process module  102  is located in a clean room  108  and connected to computer  106 . Computer  106  can provide direct control and monitoring of the processes performed in process module  102 . Additionally, attaching computer  106  to a computer network can provide remote control and monitoring of the process module  102 . The clean room  108  can provide facilities  109  capable of supplying and removing process fluids from the process module  102 . Fluid controls  112  can store the process fluids supplied by the facilities  109 . Flow from process chemical or de-ionzied water storage  114  can be controlled using flow controllers  116  and valves  118 . 
         [0030]    Process module  102  can include ambient controls  110  that can include, but are not limited to, air filters, heaters, humidifying devices and dehumidifying devices. Also found in process module  102  are various process stations. Process module  102  includes process stations A, B, and C and is intended to be exemplary as it would be possible to have a processes module with fewer or additional process stations. Process station B includes gripper assembly  121  and gripper assembly  121   a , plating assembly  120  and substrate handlers  123 . In one embodiment, the gripper assembly  121  is positioned to clamp and move a substrate  150  from the substrate handler  123  into the plating assembly  120 . Note that alternate and additional processes other than plating can be performed. Also note that processes performed by a process station can performed by a single or multiple proximity process heads. 
         [0031]    As the substrate  150  emerges from the plating assembly  120 , the gripper assembly  121   a  is positioned to receive the substrate  150 . When an appropriate amount of the substrate  150  has emerged from the plating assembly  150 , the gripper assembly  121   a  can clamp onto the substrate  150  and pull the substrate  150  through the plating assembly. In one embodiment, gripper assembly  121  continues to push the substrate  150 . In order to pass the substrate  150  through the plating assembly  120 , the gripper  121  releases the substrate  150  and the gripper  121   a  continues to pull the substrate  150 . In other embodiments, process station B can include a variety of processing assemblies and proximity heads other than, and in addition to, the plating assembly  120 . Similarly, process stations A and C can accommodate and facilitate a variety of process assemblies. 
         [0032]      FIG. 2  is a overview schematic of a gripper assembly  121  in relation to a process station  204  and substrate  150 , in accordance with one embodiment of the present invention. As illustrated and described above, the gripper assembly  121  has released the substrate  150 . In this embodiment, the substrate  150  has emerged from the process station  204 , and for clarity, the second gripper that would be pulling the substrate is not shown. In a scenario where the process station  204  performed a electroplating operation, the gripper assembly  121  and the second gripper are configured to secure the substrate using substrate clamps and apply and electrical charge with an electrode assembly that is integrated into the gripper assembly. 
         [0033]      FIG. 3  is a schematic illustrating a close up view of a gripper assembly  121  in accordance with one embodiment of the present invention. For discussion purposes, the gripper assembly  121  can be broken down into the following three subassemblies: clamp assembly  300 , electrode assembly  302  and clamp assembly  304 . Other embodiments of the gripper assembly can include a single clamp assembly or additional clamp assemblies. Similarly, additional electrode assemblies can be included in alternate embodiments of the gripper assembly  121 . In the embodiment shown in  FIG. 3 , the clamp assemblies  300  and  304  are shown in a closed positioned even though a substrate is not present. Furthermore, the electrode assembly  302  is shown in an open position. In other embodiments, the clamp assemblies can be in an open position and the electrode assembly can be in a closed position when a substrate is not present. 
         [0034]    In one embodiment, the gripper assembly  121  approaches a stationary substrate with clamp assemblies  300  and  304  in a closed position and the electrode assembly  302  in an open position. As the gripper assembly  121  approaches the substrate, the clamp assemblies  300  and  304  can be actuated into an open position. When the gripper assembly  121  is properly positioned about the substrate, the clamp assemblies  300  and  304  can be closed on the appropriate areas of the substrate. In one embodiment, the appropriate areas of the substrate include an exclusion zone at the edge of the substrate. When actuated to close, the substrate clamp assemblies  300  and  304  secure the substrate to the gripper assembly  121 . In one embodiment, the clamp assemblies  300  can move independently from clamp assembly  304 . This can allow clamp assembly  300  to close on the substrate first, followed by clamp assembly  304 , or vice versa. In other embodiments, actuation of the independent clamp assemblies  300  and  304  occurs simultaneously. 
         [0035]    After the clamp assemblies  300  and  304  have secured the substrate, electrode assembly  302  can be actuated to a closed position placing electrodes in contact with the substrate. In one embodiment, the electrodes contact the substrate in the exclusion zone at the edge of the substrate. Note that the electrode assembly  302  can be selectively applied to the substrate. This can be beneficial as gripper assemblies  121  can transport substrates through process modules that do not require the application of electrodes. In other embodiments, the gripper assembly  121  can be fabricated as modular components permitting the rapid addition, removal or replacement of an electrode assembly  302 , or clamp assembly  300  or  304  as needed. Other embodiments can allows the electrode assembly to be swapped out for an additional clamp assembly. 
         [0036]      FIG. 4  is an exploded view of the gripper assembly  121  in accordance with one embodiment of the present invention. In one embodiment, the clamp assemblies  300  and  304  include an actuator  407 , a substrate clamp  404  or substrate clamp  402 , a compression module  408  and a stop block  412 . In one embodiment, the substrate clamps  404  and  402  are coupled to a base  410  at a coupling point. The coupling point allows the substrate clamps  402  and  404  to pivot to an open position and a closed position. Also coupled to the based  410  are the actuators  407  that are capable of pivoting the substrate clamps  402  and  404  into an open position about the coupling point. 
         [0037]    The substrate clamps  402  and  404  include a feature  414  to interface with the compression module  408 . In the embodiment shown in  FIG. 4 , the feature  414  is a counterbore region to accommodate the compression module  408 . Though compression module  408  is illustrated as a spring, this is intended to be exemplary as the compression module in other embodiments can be an actuator capable of providing a constant and repeatable force on the substrate clamps  402  and  404 . 
         [0038]    The stop block  412  is coupled to a top  416  and can provide an upper limit of movement for the substrate clamps  402  and  404  when moved into the open position by the actuators  407 . In other embodiments, the stop blocks  412  are not required as the actuators  407  can be configured to limit a maximum distance of travel. 
         [0039]    The electrode assembly  302  includes a contact lever  406 , electrode manifold assembly  400 , actuator  407 , and tension module  414  (not shown). In one embodiment, the electrode manifold assembly  400  is coupled to the contact lever  406  and the contact lever  406  is coupled to the base  410 . The contact lever  406  is coupled to the base at a coupling point that allows the contact lever  406  to pivot into an open position and a closed position. Additional exemplary details regarding the electrode manifold assembly  400  will be provided below in the discussion of  FIGS. 8-8C . In one embodiment, the tension module  414  is positioned between the base  410  and the electrode manifold assembly  400 . The tension module  414  can provide a constant force that pivots the electrode manifold assembly  400  into the open position. The actuator  407 , can be coupled to the top  416  and when actuated, can lower the electrode manifold assembly  400  into the closed position. In one exemplary embodiment, the actuator  407  can be operated pneumatically while other embodiments of the actuator  407  can be operated using a variety of alternate techniques. 
         [0040]      FIG. 5  and  FIG. 6  are schematics of substrate clamps  402  and  404  in accordance with embodiments of the present invention. The substrate clamps  402  and  404  have a bottom side that includes a clamping surface  500 . With a substrate present and the substrate clamps  402  and  404  in a closed position, the clamping surface  500  will be in contact the substrate. The substrate clamps  402  and  404  illustrated in  FIGS. 5 and 6  are configured to accommodate a circular substrate having a diameter of about 300 mm. As the clamping surface  500  is intended to contact as exclusion area of the substrate, the clamping surface  500  is partially defined by two radii, R 1  and R 2 . In one embodiment, R 1  is about 145 mm and R 2  is about 150 mm. Note that the listed values for R 1  and R 2  are exemplary for a substrate having a diameter of about 300 mm. One skilled in the art should recognize that the values of R 1  and R 2  could be modified in order to fabricate substrate clamps to accommodate substrates of alternate diameters. Furthermore, the use of circular substrates and the subsequent radii of the substrate clamp are not intended to be limiting. Other embodiments of substrate clamps  402  and  404  can be configured to accommodate non-circular substrates. 
         [0041]    In one embodiment, the substrate clamps  402  and  404  can have an overall length L, of about 66 mm, a width W, of about 20 mm, and a height H, of about 20 mm. Pivot hole  506  can traverse the width of the substrate clamp  402  or  404  and provide the coupling location between the substrate clamp and the base. 
         [0042]      FIG. 7  is an illustration of a contact lever  406  in accordance with one embodiment of the present invention. Thru hole  702  traverses the contact lever  406  and allows the tension module to be secured against a base and the electrode manifold assembly. Mounting holes  700   a  and  700   b  are defined to provide a coupling location between the electrode manifold assembly and the contact lever  406 . Pivot hole  704  can traverse the width of the contact lever  406  and provide a coupling point between the contact lever  406  and the base. 
         [0043]      FIG. 8  is an illustration of the electrode manifold assembly  300  in accordance with one embodiment of the present invention. In one embodiment, the electrode manifold assembly  300  includes a contact manifold  800 , electrode arms  804 , and electrode diffusers  802 . The individual components of the electrode manifold assembly  300  are discussed below. 
         [0044]      FIG. 8A  is an illustration of the electrode manifold  800 , in accordance with one embodiment of the present invention. Mounting holes  814  are positioned to provide a coupling location between the electrode manifold and the contact lever. Additionally, outlet holes  810  are positioned and sized to accommodate electrode tubes. The outlet holes  810  intersect a gas manifold  816 , the gas manifold having two openings at port  812  and port  818 . The gas manifold  816  allows pressurized gas that is input through either port  812  or port  818  to be distributed to the outlet holes  810 . 
         [0045]      FIG. 8B  is an illustration of an electrode arm  804  in accordance with one embodiment of the present invention. In one embodiment, the electrode arm  804  is a hollow cylinder formed from an electrically conductive material. The electrode arm  804  has an overall length of about 23 mm, an outer diameter of about 2 mm and an inner diameter of about 1 mm. The electrode arm  804  also has a manifold end  820  and an electrode end  822 . The manifold end  820  is configured to couple with the outlet hole  810  of the electrode manifold  800  while the electrode end  822  is configured to couple with the electrode diffuser  802 . As pressurized gas can be transited through the hollow of the electrode arm  804 , the couplings between the manifold end  820  and the electrode manifold  800  can be substantially airtight. Similarly, the coupling between the electrode end  822  and the electrode diffuser  802  can also be substantially airtight. The embodiments described above are exemplary and should not be considered limiting as the electrode arm  804  can be constructed from a variety of materials having a variety of cross-sectional profiles. For example, other embodiments of the electrode arm  804  can be constructed from tubing with a triangular, square, pentagonal, hexagonal, etc. cross-section. 
         [0046]      FIG. 8C  is an exemplary schematic of an electrode diffuser  802  in accordance with one embodiment of the present invention. The electrode diffuser  802  can be made from an electrically conductive material and be substantially cylindrical with the largest diameter D, measuring about 3 mm. In one embodiment, the electrode diffuser  802  has an overall length L, of about 3 mm. A first end of the electrode diffuser  802  has a coupling cavity  830  configured to mate with the electrode end of the electrode tube. On a second end, the end opposite from coupling cavity  830 , there are a plurality of holes  834  that traverse from the second end through to the coupling cavity. The holes  834  can act to diffuse compressed gas transited through the electrode arms toward the substrate. 
         [0047]    The electrode tip  835  is axially aligned with the electrode diffuser and extends from the second end of the electrode diffuser  802 . The electrode tip  835  can have a contact surface  832  that is substantially cylindrical with a diameter d, of about 0.8 mm. Furthermore, the contact surface  832  can be offset from the second end of the electrode diffuser  802  by about 1 mm. When the electrode assembly  400  placed in the closed position, an electrical charge can be applied to the electrode assembly  400 . The electrical charge can travels across the electrically conductive electrode arm  804  to the substrate via the electrode tip  802 . Concurrently with the application of electrical charge, compressed gas can be delivered through the hollow of the electrode arm  804  and applied to the substrate through the diffuser  802 . The application of compressed gas can disperse heat generated from the flow of electrical charge between the electrode tip and the substrate. 
         [0048]      FIG. 9  is a schematic illustrating a side view of a substrate clamp assembly installed in a gripper assembly in accordance with one embodiment of the present invention. In this embodiment, the compression module  408  is a spring that applies a constant force to the substrate clamp  404  resulting in the substrate clamp  404  defaulting to a closed position. To open the substrate clamp  404 , the actuator  407  pushes the substrate clamp  404  which pivots the substrate clamp  404  about the coupling point  506  and lifts the clamping surface  500 . 
         [0049]      FIG. 10  is a schematic illustrating a side of an electrode assembly installed in a gripper assembly in accordance with one embodiment of the present invention. In this embodiment, the tension module  414  is a spring that can apply a constant force to the electrode manifold  400  resulting in the electrode assembly defaulting to an open position. To place the electrode assembly in a closed position, the actuator  407  pushes down on the electrode assembly thereby lowering the electrode tips into contact with the substrate. Note that as the electrode tips come into contact with the substrate, the electrode arms  804  can flex providing a spring effect to facilitate a highly reliable electrical contact with the substrate. 
         [0050]      FIG. 11A  and  FIG. 11B  are schematics illustrating various clamping distances, and comparative deflections of the substrate  150 , in accordance with embodiments of the present invention. In one embodiment, a single gripper assembly initially holds a substrate  150  in two substrate clamps separated by a clamping distance. The clamping distance can be defined as a distance X from the edge of the substrate  150 . Alternately, the clamping distance can be defined as a distance Y between the clamping areas  500 . 
         [0051]    Regardless of the clamping distance, once held in place by the substrate clamps, the substrate  150  can act as a cantilevered member. As illustrated in  FIGS. 11   a  and  11   b , the mass of the substrate  150  can create a moment arm with a fulcrum located approximately where the substrate clamps are contacting the substrate  150 . This moment arm can result in the substrate  150  deflecting a distance d. Note that the deflection d illustrated in  FIGS. 11A and 11B  is exaggerated for illustrative purposes. Commensurate with deflection d, is the induction of stress and strain within the substrate  150 . Thus, the clamping distance, and the subsequent deflection of the substrate  150 , can be partially constrained by the sensitivity of the substrate  150  to stress and strain. Another possible constraint on the clamping distance is the width of a process assembly. A wide process assembly may necessitate a smaller clamping distance as a majority of the substrate may be contained within the process assembly. Conversely, a narrow process assembly may permit a larger clamping distance. 
         [0052]      FIG. 12A  and  FIG. 12B  are schematic illustrations of a transport system for moving the gripper assemblies in accordance with one embodiment of the present invention. Viewed from an end, gripper assembly  121  can be seen at the end of an arm  1202 . The Arm  1202  can be coupled to guide  1204   a  and guide  1204   b . The guides  1204   a  and  1204   b  can configure to restrict motion of the arm in a direction normal to a rail  1206 . In one embodiment, the rail  1206  is part of a linear actuator that allows the arm  1202  to move in the direction X, as shown in  FIG. 12B . 
         [0053]    A moment is developed on the arm  1202  based on the mass of the gripper assembly and addition of a substrate when present in the gripper. Thus, the material and shape of the arm  1202  can be chosen based on its ability to resist deflection. As potentially corrosive process fluids may be used in close proximity to the arm  1202 , an additional consideration is the chemical resistivity of a material for the arm  1202 . In one embodiment, the arm  1202  is fabricated using American Society for Testing and Materials (ASTM) stainless steel type  316 . In other embodiments, different materials such as plastic, non-ferrous metals, coated ferrous metals and alternate types of stainless steel may be used. 
         [0054]      FIG. 13  is a flow chart illustrating a procedure that transport a substrate through a processing assembly in accordance with one embodiment of the present invention. The procedure begins with operation  1302  where the substrate clamps and electrode assembly for a first gripper assembly are placed in an open position. Operation  1304  is next and the first gripper assembly is moved into a position to hold the substrate. Next, operation  1306  closes the substrate clamps on the substrate, which is followed by operation  1308  that closes the electrode assembly on the substrate. The procedure continues with operation  1310  that moves the substrate into a substrate processing assembly. This is followed by operation  1312  where the substrate clamps and electrode assembly of the second gripper assembly are placed in an open position. 
         [0055]    Operation  1814  is next and positions the second gripper assembly in a location to receive the substrate, as it emerges processed, from the process assembly. Once enough of the processed substrate has emerged from the process assembly, operation  1316  closes the substrate clamps of the second gripper assembly on the processed substrate. This is followed by operation  1318  where the electrodes assembly of the second gripper assembly is closed on the processed substrate. Operation  1320  continues the procedure as the first and second grippers continue to move the substrate through the process assembly. At a particular point, operation  1322  opens the electrode assembly of the first gripper assembly followed by operation  1324  that opens the substrate clamps of the first gripper assembly. 
         [0056]    Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.