Abstract:
Protected magnets and magnet shielding for processing microfeature workpieces, and associated systems and methods are disclosed. A tool in accordance with one embodiment includes a process chamber having a process location for processing microfeature workpieces, a support positioned to carry a microfeature workpiece at the process location, a transfer device movable relative to the support to move the microfeature workpieces to and from the support, and a magnet positioned adjacent to the process chamber to magnetically orient materials applied to the microfeature workpieces. The tool can include other features, including an enclosure positioned around the magnet to chemically isolate the magnet from chemicals delivered to and carried in the process chamber, a shield positioned between the magnet and the motion path of the transfer device, magnetically conductive return paths positioned proximate to the magnet, and/or shields positioned around the motors carried by the tool.

Description:
TECHNICAL FIELD 
       [0001]    The present invention is related to protected magnets and magnet shielding for processing microfeature workpieces, and associated systems and methods. Systems in accordance with the invention include processing tools with magnets that are enclosed to protect them from the local chemical environment. Shielding is positioned between the magnets and other components of the system to protect the components from magnetic fields. 
       BACKGROUND 
       [0002]    Microelectronic devices are fabricated on and/or in microelectronic workpieces (e.g., wafers) using several different processing apparatuses or tools. Many such processing tools have a single processing station that performs one or more procedures on the workpieces. Other processing tools have a plurality of processing stations that perform a series of different procedures on individual workpieces or batches of workpieces. The workpieces are often handled by automatic handling equipment (e.g., robots or transfer devices) because microelectronic fabrication requires very precise positioning of the workpieces, and/or due to conditions that are not suitable for human access (e.g., vacuum environments, high temperature environments, chemical environments, clean environments, etc.). 
         [0003]    An increasingly important category of processing tool is a plating tool that plates metal and other materials onto workpieces. Existing plating tools use automatic handling equipment to handle the workpieces because the position, movement and cleanliness of the workpieces are important parameters for accurately plating materials onto the workpieces. The plating tools can be used to plate metals and other materials (e.g., ceramics or polymers) in the formation of contacts, interconnects and other components of microelectronic devices. For example, copper plating tools are used to form copper contacts and interconnects on semiconductor wafers, field emission displays, read/write heads and other types of microelectronic workpieces. A typical copper plating process involves depositing a copper seed layer onto the surface of the workpiece using chemical vapor deposition (CVD), physical vapor deposition (PVD), electroless plating processes, or other suitable methods. After forming the seed layer, copper is plated onto the workpiece by applying an appropriate electrical field between the seed layer and an anode in the presence of an electrochemical plating solution. The workpiece is then cleaned, etched and/or annealed in subsequent procedures before transferring the workpiece to another tool or apparatus. 
         [0004]    In at least some instances, it is desirable to expose the material being deposited on the workpiece to a magnetic field that orients the material in a particular direction relative to coordinates of the workpiece. For example, it is desirable to plate a ferromagnetic material on the workpiece with a uniform magnetic orientation when the workpiece is to be used for computer hard drive components. It is important in such cases to orient the ferromagnetic material properly with respect to the workpiece by placing a strong magnet proximate to the process chamber during the deposition process. However, one drawback with the foregoing approach is that the effects of the magnet on the other devices and components of the tool are typically unknown and/or potentially harmful to those devices. In addition, the environment in the tool may have potentially harmful effects on the magnet. 
         [0005]    In light of the foregoing, it is desirable to provide protected and/or shielded magnets for processing microfeature workpieces. It would also be desirable to incorporate such features into a processing tool without having a significant effect on other components of the tools, and without significantly increasing the size of the tool, as doing so will increase the footprint of the tool and therefore the amount of (expensive) clean room space occupied by the tool. 
       SUMMARY 
       [0006]    The present invention provides processing tools and associated methods directed to protecting a magnet used during microfeature workpiece processing, and/or protecting other components of the tool from the effects of the magnet. The magnet is positioned adjacent to a process chamber of the tool to magnetically orient materials applied to a microfeature workpiece. An enclosure is positioned around the magnet to isolate the magnet from chemicals delivered to and carried in the process chamber, thus protecting the magnet. In another arrangement, the tool includes a transfer device that moves workpieces to and from the chamber. A magnetically conductive shield is positioned between the magnet and the motion path of the transfer device to shield the transfer device from the magnetic field generated by the magnet. This arrangement protects the transfer device from interference by the magnet. The shield used to protect the transfer device doubles as (or can be supplemented with) a magnetically conductive return path that orients (e.g., straightens) the magnetic field within the process chamber to more consistently and reliably orient materials deposited on the workpiece at the chamber. Devices other than the transfer device may also be protected from the effects of the magnet. For example, motors used to drive an associated workpiece support (which carries the workpiece at the process chamber) are shielded, as is a motor that agitates the fluid within the process chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a top isometric view of a tool having one or more processing stations with magnets arranged in accordance with embodiments of the invention. 
           [0008]      FIG. 2  is a partially exploded illustration of a tool structure including decks configured to support tool components in accordance with an embodiment of the invention. 
           [0009]      FIG. 3  is a partially cut-away, top isometric view of the tool structure shown in  FIG. 2 , with a magnet assembly installed in accordance with an embodiment of the invention. 
           [0010]      FIG. 4  is a partially schematic, isometric illustration of the tool structure shown in  FIG. 3 , with the tool deck carrying a processing chamber and a support in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    The following description discloses the details and features of several embodiments of tools for processing microfeature workpieces in the presence of magnetic fields, and methods for making and using such devices. The terms “microfeature workpiece” and “workpiece” refer to substrates on and/or in which micro-devices are formed. Typically, micro-devices include microelectronic circuits or components, thin-film recording heads, data storage elements, micro-fluidic devices, and other products. Micro-machines and/or micromechanical devices are included within this definition because they are manufactured in much the same manner as integrated circuits. The substrates can be semiconductive pieces (e.g., silicon wafers or gallium arsenide wafers), non-conductive pieces (e.g., various substrates), or conductive pieces (e.g., doped wafers). It will be appreciated that several of the details set forth below are provided to describe the following embodiments in a manner sufficient to enable a person skilled in the art to make and use the disclosed embodiments. Several of the details and advantages described below, however, may not be necessary to practice certain embodiments of the invention. Additionally, the invention may also include other embodiments that are also within the scope of the claims, but are not described in detail with reference to  FIGS. 1-4 . 
         [0012]      FIG. 1  is a partially schematic, isometric illustration of a tool  100  that performs one or more wet chemical or other processes on microfeature workpieces W. The tool  100  includes a housing or cabinet (removed for purposes of illustration) that encloses a deck  110 . The deck  110  supports a plurality of processing stations  130  and a transport system  140 . The stations  130  can include rinse/dry chambers, cleaning capsules, etching capsules, electrochemical deposition chambers, annealing chambers, or other types of processing chambers. Individual processing stations  130  include a vessel, reactor, or chamber  131  and a workpiece support  132  (for example, a lift-rotate unit) for supporting an individual microfeature workpiece W during processing at the chamber  131 . The transport system  140  moves the workpiece W to and from the chamber  131 . Accordingly, the transport system  140  includes a transfer device  142  or robot that moves along a linear guide path  141  to transport individual workpieces W within the tool  100 . The tool  100  further includes a workpiece load/unload unit  101  having a plurality of containers for holding the workpieces W as they enter and exit the tool  100 . 
         [0013]    In operation, the transfer device  142  has a first carrier  143  with which it carries the workpieces W from the load/unload unit  101  to the processing stations  130  according to a predetermined workflow schedule within the tool  100 . Typically, each workpiece W is initially aligned at a pre-aligner station  130 a before it is moved sequentially to other processing stations  130 . At each processing station  130 , the transfer device  142  transfers the workpiece W from the first carrier  143  to a second carrier  133  located at the workpiece support  132 . The second carrier  133  then carries the workpiece W for processing at the corresponding process chamber  131 . A controller  102  receives inputs from an operator and, based on the inputs, automatically directs the operation of the transfer device  142 , the processing stations  130 , and the load/unload unit  101 . 
         [0014]      FIG. 2  is a partially exploded, isometric view of a portion of the underlying structure of the tool  100  shown in  FIG. 1 . The deck  110  of the tool  100  includes a first portion  111   a  having a first deck surface  113   a , and a second portion  111   b  having a second deck surface  113   b . The deck portions  111   a ,  111   b  are positioned on opposite sides of a transfer device “gulley”  112 . The transfer device gulley  112  supports the transfer device  142  ( FIG. 1 ) for motion along the guide path  141  so that the transfer device  142  can access processing stations carried by either the first deck surface  113 a or the second deck surface  113   b . In some instances, the deck surfaces  113   a ,  113   b  are at different elevations (e.g., with the second deck surface  113   b  higher than the first deck surface  113 a), and in such cases, the transfer device  142  ( FIG. 1 ) is configured to access processing stations at both elevations. 
         [0015]    The first and second deck surfaces  113   a ,  113   b  include chamber mounts  127  for carrying processing chamber components, and support mounts  126  for carrying workpiece support components. Each deck surface  113   a ,  113   b  also includes a chamber opening  125  that accommodates a chamber  131  ( FIG. 1 ) or a portion of the chamber  131  that extends below the corresponding deck surface. The deck surfaces  113   a ,  113   b  and the transfer device gulley  112  have registration features  116 , including first registration features  116   a , second registration features  116   b , and third registration features  116   c . The registration features  116  include precision mating elements (e.g., fixed alignment pegs and corresponding holes) that provide for precise alignment between the components of the tool  100 . Accordingly, transfer device components engaged with the third registration features  116   c  (in the transfer device gulley  112 ) will be in precise alignment with processing station components engaged with the first registration features  116   a  (at the first deck surface  113   a ), and with processing station components engaged with the second registration features  116   b  (at the second deck surface  113   b ). This arrangement reduces or eliminates misalignments between the transfer device  142  ( FIG. 1 ) and the processing stations  130  ( FIG. 1 ). 
         [0016]    The second portion  111   b  of the deck  110  includes an enclosure  120  carried by a subdeck surface  114 . Accordingly, the enclosure  120  includes fourth registration features  116 d that engage with fifth registration features  116 e carried by the subdeck surface  114 . This arrangement preserves the precise alignment between transfer device components in the transfer device gulley  112 , and processing station components carried at the second deck surface  113   b.    
         [0017]    In addition to maintaining the registration between transfer device components and processing station components, the enclosure  120  protects components housed within it from the chemical environment present in the tool  100 . These components include relatively large, powerful (and therefore heavy) magnets described in further detail below with reference to  FIGS. 3 and 4 . In the illustrated embodiment, the enclosure  120  includes a base  122 , a top  121  (the external surface of which also corresponds to the second deck surface  113   b ), opposing end walls  123 , and opposing side walls  124  (shown partially cut-away). The enclosure  120  is also defined by chamber opening walls  128  that surround the chamber opening  125 . This box-type arrangement forms a structurally stiff enclosure  120 , suitable for carrying heavy components, including the large magnets. In particular, the sidewalls  124 , end walls  123 , and/or chamber opening walls  128  provide a load path between the base  122  and the top  121 , allowing the top  121  to supplement the support provided by the base  122 . Furthermore, the base  122 , side walls  124 , end walls  123 , chamber opening walls  128 , and top  121  are connected to each other in such a manner as to form a chemical-tight (or at least chemically resistant) boundary around the magnets. In a particular arrangement, the components of the enclosure  120  are welded together and coated with a gas- and/or liquid-tight sealant. Suitable sealants include powder-coat polymer paints. This arrangement protects components within the enclosure  120  from the chemical environment outside the enclosure  120 . In particular, this arrangement protects the magnets, which are typically formed from magnetite or other materials that are otherwise very susceptible to corrosion, from chemicals outside the enclosure  120 . 
         [0018]      FIG. 3  is a top isometric view of the deck arrangement shown in  FIG. 2 , with the enclosure  120  mounted to the subdeck surface  114 , and with a portion of the second deck surface  113   b  cut away to expose components within the enclosure  120 . These components include a magnet assembly  150 , that in turn includes a first magnet  151 a positioned on one side of the chamber opening  125 , and a second magnet  151   b  positioned on the opposite side of the chamber opening  125 . Corresponding magnet supports  153   a  and  153   b  secure the first and second magnets  151   a ,  151   b  in position. 
         [0019]    The magnetic flux lines between the two magnets  151   a ,  151   b  tend to bulge outwardly and/or stray from the region between the two magnets, in the absence of measures taken to direct the flux lines. This can produce adverse effects, including (a) a skewed magnetic field in any process chamber located between the magnets  151   a ,  151   b , and/or (b) interference with motors and/or other electronic equipment carried by the tool. In at least some cases, the skewed magnetic field adversely affects the uniformity of the material deposited on a workpiece in the process chamber, and the interference adversely affects the rate and/or accuracy with which components in the tool operate. Aside from the magnets  151   a ,  151   b  and possibly the magnet supports  153   a ,  153   b , most, if not all of the components making up the deck  110  are generally non-magnetic. For example, the deck surfaces  113   a ,  113   b , the subdeck  114 , and the enclosure  120  are typically formed from stainless steel (e.g., a 300-series stainless steel, such as 304 stainless steel) or another corrosion-resistant non-magnetic material, and are generally relatively thin. Accordingly, they have little or no effect on the magnetic flux lines between the magnets  151   a ,  151   b.    
         [0020]    To address the foregoing, the illustrated magnet assembly  150  includes a first magnetic return path  152   a  positioned between the first and second magnets  151   a ,  151   b  on one side of the chamber opening  125 , and a second magnetic return path  152   b  positioned on the opposite side of the chamber opening  125 . The first and second magnetic return paths  152   a ,  152   b  align the magnetic flux lines between the first magnet  151   a  and the second magnet  151   b  to be generally parallel to the return paths  152   a ,  152   b  and generally transverse (e.g., perpendicular) to the first and second magnets  151   a ,  151   b , as indicated by magnetic flux lines B. One advantage of this arrangement is that the magnetic flux lines B will have a known and generally consistent orientation across the chamber opening  125  and accordingly throughout a process chamber  131  ( FIG. 1 ) installed in the chamber opening  125 . This feature is expected to produce more uniform deposition results for microfeature workpieces that are processed at the process chamber  131 . 
         [0021]    Another feature of the illustrated magnet assembly  150  is that the second magnetic return path  152   b , in addition to aligning the magnetic flux lines in the manner described above, acts as a shield between the magnets  151   a ,  151   b  and the transfer device gulley  112 . As discussed further with reference to  FIG. 4 , the shield can form part of an overall shielding arrangement that reduces the effects of the magnetic fields created by the magnets  151   a ,  151   b  on other components within the tool  100 . 
         [0022]    Still another feature of the illustrated magnet assembly  150  is that it is arranged to provide for long component life spans, ease of manufacturability, and ease of maintenance. For example, the first magnetic return path  152   a  is housed in the enclosure  120 . This component is typically formed from a ferromagnetic material and accordingly may be susceptible to corrosion without the protection of the enclosure  120 . In some embodiments, the second magnetic return path  152   b  is also placed in the enclosure  120  to provide similar protection. In the embodiment illustrated in  FIG. 3 , however, the second magnetic return path  152   b  is positioned exterior to the enclosure  120 , and out of contact with the first and second magnets  151   a ,  151   b . In this position, the second magnetic return path  152   b  can still direct the magnetic flux lines B in the desired manner, and can also enhance manufacturing and maintenance operations. For example, by not attaching the second magnetic return path  152   b  to the other components of the magnet assembly  150 , the magnet assembly  150  has an open-ended shape, formed by the two magnets  151   a ,  151   b , the magnet supports  153   a ,  153   b , and the first magnetic return path  152   a . This configuration can be easily installed into the enclosure  120  by sliding it toward the transfer device gully  112 , without disturbing the second deck surface  113   b . If necessary, this portion of the magnetic assembly  150  can be removed by sliding it away from the transfer device gully  112  and out of the enclosure  120 . The second magnetic return path  152   b  can be separately protected from the chemical environment within the tool  100  by coating it with an appropriate sealant/coating, as described above in the context of the enclosure  120 . If it becomes necessary to replace the second magnetic return path  152   b , the replacement operation is completed without disturbing the enclosure  120 . 
         [0023]      FIG. 4  illustrates the tool  100  with a process chamber  131  positioned at one of the chamber mounts  127  so as to extend into a corresponding chamber opening (hidden by the process chamber  131 ). A support  132  is positioned at a corresponding support mount  126 . The support  132  includes a second carrier  133  that carries a workpiece W in contact with processing liquid in the chamber  131 . In this particular arrangement, the process chamber  131  includes an agitator  134  that agitates the processing fluid adjacent to the workpiece. Accordingly, the station  130  includes an agitator drive motor  135  that drives the agitator  134 , and a carrier drive motor  136  that drives the second carrier  133 . In order to protect these motors from the potentially interfering effects of the magnet assembly  150 , the agitator drive motor  135  includes a magnetically conductive agitator motor shield  162 , and the carrier drive motor  136  includes a magnetically conductive carrier motor shield  137 . 
         [0024]    The illustrated tool  100  also includes a transfer device shield  161  positioned between the magnet assembly  150  and the transfer device gulley  112 . In this manner, the motors carried by the transfer device  142  are shielded from the effects of the magnet assembly  150 . In a particular arrangement, the same structure functions as both the transfer device shield  161  and the second magnetic return path  152   b . This configuration preserves the compact configuration of the tool  100  (by combining multiple functions in a single structure), thus reducing the amount of expensive clean-room floor space occupied by the tool  100 . In other embodiments, the transfer device shield  161  and the second magnetic return path  152   b  include separate structures. 
         [0025]    From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the invention. For example, the transfer device shield  161  which can double as the second magnetic return path  152   b  can be located inside the enclosure  120 , rather than outside the enclosure as is shown in  FIGS. 3 and 4 . Or, the second magnetic return path  152   b  can be located within the enclosure  120 , and the transfer device shield  161  can be located outside the enclosure  120 . The materials and compositions of the components described above may be different in other embodiments. For example, the enclosure  120  and/or other deck components may include plastics or other non-conductive, chemically resistant materials. The shields positioned around the support motor and/or the agitator motor can be located remote from the motors while still providing a shielding function. Shielding may be provided around components other than the motors identified above, for example, around a spin motor carried by the support to spin the workpiece during processing. Certain aspects of the invention described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, the tool  100  shown in the Figures may include more or fewer processing stations in other embodiments. Further, while advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.