Abstract:
A method and apparatus for a modular processing system is described. The apparatus includes a transfer chamber as the foundation for the system and includes sidewalls adapted to receive at least three 200 mm and/or 300 mm process chambers. The transfer chamber includes a robot capable of withstanding high temperatures and is configured to transfer 200 mm and 300 mm substrates. The modularity of the transfer chamber is highly transportable and provides a research and development platform at a low cost of ownership and may be modularly built into a production system as additional chambers and peripheral hardware is added.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to semiconductor processing equipment. More particularly, the invention relates to a semiconductor processing system having modular capabilities and a small footprint. 
         [0003]    2. Description of the Related Art 
         [0004]    The semiconductor fabricating field is a highly dynamic industry that continues to meet evolving consumer demands while overcoming tremendous engineering obstacles. While there is a constant drive to make electronic devices smaller than the state of the art, the majority of device manufacturers rely on proven production tools to produce proven and marketable state of the art devices to meet consumer demand at a reasonable profit. 
         [0005]    One commonly utilized production tool is a cluster-type tool, which generally includes a plurality of process chambers coupled to a central transfer chamber. Another type of conventional production tool is an in-line system, which generally includes a plurality of linearly arranged process chambers and a transfer device utilized to transfer substrates between the various process chambers. The typical production tool has many large and heavy components, is time consuming to assemble, and generally requires a permanent or semi-permanent space in a clean room as it cannot be moved easily. These tools are typically highly efficient, enabling high throughput and good process repeatability, and this typically results in higher profitability for the manufacturer. The typical production tool also requires a significant capital outlay and any profitability is highly dependent on the tool remaining on-line, with little or no process interruption other than required or scheduled maintenance. 
         [0006]    In the quest for smaller device sizes and more efficient manufacturing parameters, a manufacturer may develop a new process or fabrication recipe that will need to be tested prior to release for production. To perform this test, the tool must be taken off-line to test the process sequence or recipe. The tool must be calibrated to test the recipe, process at least one wafer, and be re-calibrated to bring the tool back on-line with normal production. Due to this interruptive testing, which results in extensive downtime and may endure one day or longer, a manufacturer may not be able to absorb the cost of research and development (R&amp;D) with the typical production tool used in this manner. Further, start-ups or other interested parties may be prohibited from R&amp;D due to the high initial capital outlay for the production tool and its required clean room space. Also, a manufacturer may desire to reconfigure the tool, which may be difficult due to the platform arrangement of the typical production tool. 
         [0007]    What is needed is a modular tool designed for R&amp;D and start-ups with production potential that requires minimal clean room space and may be easily built or reconfigured according to user desires. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments disclosed herein describe a small footprint modular transfer chamber for transferring substrates, such as semiconductor wafers. The transfer chamber is capable of coupling with a plurality of process chambers that may be a combination of 200 mm and 300 mm process chambers. 
         [0009]    In one embodiment, a small footprint transfer chamber is described. The transfer chamber includes a body including an interior volume bounded by at least four sidewalls, a substrate transfer port formed through each of the sidewalls, and a transfer robot positioned within the interior volume, the transfer robot configured to withstand temperatures in excess of 100 degrees C. 
         [0010]    In another embodiment, a small footprint transfer chamber is described, which includes at least three sidewalls adapted to couple to a plurality of 200 mm and/or 300 mm process chambers, and a robot having an end effector suitable for transferring 200 mm and 300 mm substrates, wherein the transfer chamber defines a plan area less than about 1000 square inches. 
         [0011]    In another embodiment, a small footprint transfer chamber is described, which includes a body including an interior volume bounded by at least three sidewalls adapted to couple to a plurality of 200 mm and/or 300 mm process chambers, a substrate transfer port formed through each of the sidewalls, and a transfer robot positioned within the interior volume, the transfer robot configured to withstand temperatures in excess of  100  degrees C, wherein the robot includes an end effector suitable for transferring 200 mm and 300 mm substrates. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    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. 
           [0013]      FIG. 1A  is a top view of one embodiment of a transfer chamber. 
           [0014]      FIG. 1B  is a side view of the transfer chamber of  FIG. 1A . 
           [0015]      FIG. 1C  is a schematic top view of one embodiment of a robot. 
           [0016]      FIG. 1D  is a schematic top view of another embodiment of the robot shown in  FIG. 1C . 
           [0017]      FIG. 2  is an exploded isometric view of another embodiment of a transfer chamber. 
           [0018]      FIG. 3  is a schematic view of one embodiment of a modular processing system. 
           [0019]      FIG. 4  is a schematic view of another embodiment of a modular processing system. 
           [0020]      FIG. 5  is an isometric view of another embodiment of a processing system. 
       
    
    
       [0021]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is also contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
       DETAILED DESCRIPTION 
       [0022]    Embodiments of the invention provide a transfer chamber that allows users, such as manufacturers or researchers, among others, to build a processing system that is highly modular, thus allowing the manufacturer or researcher to purchase processing equipment on an as-needed basis to build a production system without a significant capital expenditure. The transfer chamber and the modularity of the processing system also allows users to build the system to any desired configuration or reconfigure the processing system as the need arises. 
         [0023]      FIG. 1A  is a top view of one embodiment of a transfer chamber  100  that, in one embodiment, forms the foundation of a modular processing system. The transfer chamber  100  includes a body  2  bounded by sidewalls  3 . A transfer robot  5  is disposed in an interior volume  4  of the body  2 . The transfer robot  5  is located at substantially a center-line of the transfer chamber  100 . The transfer robot  5  includes at least one end effector  7  configured to support and transport a substrate  8 , which may be a 200 mm or 300 mm semiconductor wafer, into and out of substrate transfer ports  10  formed in the sidewalls  3  of the chamber  100 . 
         [0024]    In one embodiment, the transfer chamber  100  is rectangular and each sidewall  3  includes a substrate transfer port  10  having an opening sized to allow passage of a 300 mm substrate. Each substrate transfer port  10  includes valves  14  that are adapted to maintain negative pressure within the transfer chamber  100 . The valves  14  may be coupled to the chamber  100  within the interior volume  4  as shown, or may be coupled to the chamber  100  on the exterior of the sidewalls  3 . The valves  14  are configured to selectively seal the interior volume  4  of the transfer chamber  100  and allow coupling of a process chamber (not shown) with the transfer chamber  100 . The transfer chamber  100  may further include a port  15  for coupling to a source of negative pressure, such as a vacuum pump (not shown). The port  15  may be coupled to the bottom of the transfer chamber  100  as shown, or may be coupled to another portion of the body  2 , such as a sidewall  3  as shown in  FIG. 2 . 
         [0025]      FIG. 1B  is a side view of the transfer chamber  100  shown in  FIG. 1A . A lid  9  is shown covering an upper surface of the transfer chamber  100 , and a main frame  11  supports the chamber from the bottom. The lid  9  is removable to provide access to the robot  5  and other portions of the interior volume  4  of the transfer chamber  100  for maintenance and inspection. The lid  9  and body  2  are sealed by an O-ring or gasket disposed between the lid and the upper surface of the transfer chamber  100 . The transfer chamber  100  may be fabricated from process resistant materials such as metals, for example aluminum, stainless steel, or alloys thereof. The transfer chamber  100  may also be made of process resistant plastics or ceramic materials having the structural integrity to withstand and maintain negative pressure within the transfer chamber  100 . The transfer chamber  100  may be formed from a solid piece of material by machining, or formed from a plurality of machined pieces and joined, such as by welding. 
         [0026]    In one embodiment, the robot  5  is adapted for high heat operation within the interior volume  4 . For example, the transfer robot  5  is configured to withstand temperatures greater than about 80 degrees C., for example, greater than about 100 degrees C., such as between about 120 degrees C. to about 150 degrees C. The high temperature capability is provided by temperature resistant parts, such as metal belts  5 B, which control the articulation of the robots arms and/or end effector. The metal belts  5 B replace traditional belt material used in conventional designs to facilitate high-heat operation. 
         [0027]    In this embodiment, the transfer chamber  100  may further include a heat source  12 , such as a resistive heater, lamps, fluid conduits, and/or heating tape, coupled thereto or formed within the sidewalls  3  or other portions of the chamber  100  to preheat or post-heat the substrate within the interior volume  4  of the transfer chamber  100 . 
         [0028]    The transfer robot  5  is configured to facilitate transfer of the substrate  8  into, out of, and within the interior volume  4 . In one embodiment, the transfer robot  5  is adapted to transfer both 200 mm and 300 mm substrates without significant adjustments to the configuration and movement paradigms of the transfer robot  5 . For example, the end effectors  7  may be designed to support 200 mm and 300 mm substrates without the need to replace the end effectors or adjust the end effector length. The inventors adapted the arm  5 A and end effector  7  of the transfer robot  5  to extend through the substrate transfer ports  10  and the valves  14  to allow additional extension of the robot  5 . For example, the length of the end effector  7  is such that additional extension is realized. Also, the thickness of the arm  5 A has been adjusted to provide additional extension of the robot  5 , wherein the arm  5 A is configured to extend at least partially through the substrate transfer ports  10 . In this manner, the robot has a sufficient extended length to transfer 200 mm substrates, as well as 300 mm substrates with only a differing position of the substrate on the end effector. For example, a 300 mm substrate may occupy one area of the end effector, and a 200 mm substrate will occupy a lesser area of the end effector. To facilitate the dual dimensions, the end effector  7  may include arcuate recesses at one or both ends of the end effector, and these recesses are adapted for each substrate diameter. 
         [0029]    The transfer chamber  100  is configured to occupy a small foot print, is lightweight, and is proportioned to facilitate mobility throughout a clean room without the use of heavy lifting equipment such as cranes, jacks, skates, fork lifts, and the like, which are typically needed to move conventional transfer chambers. As an example of size, the transfer chamber  100  and  200  of  FIGS. 1A and 2 , has a width of about 25 inches (63.5 cm), which allows the transfer chamber to be easily moved into a manufacturing facility, and through personnel doors throughout a clean room. The transfer chamber  100 , as well as other components, may be delivered to the facility in a clean room package and brought into the facility through personnel pass-throughs, such as air showers and other standard personnel doors, in the facility. In one embodiment, the transfer chambers  100 ,  200  have a plan area, defined by the area or dimensions, such as width and length of the body  2 , as viewed from above, wherein the plan area has at least one dimension that is less than the width of a standard personnel door in a manufacturing facility. Conventional personnel pass-throughs may typically be between about 36 inches (91.44 cm) wide, and the width of the transfer chambers are sized to easily pass therethrough. This is beneficial as conventional transfer chambers have a short side dimension greater than 36 inches (91.44 cm), and thereby cannot enter the clean room through personnel doors. Depending on the facility, this larger size may require entry into the facility through equipment doors, which may result in a significant disruption of the facility along with the time and personnel required to move the equipment through the doors into the clean room. 
         [0030]    The transfer chamber  100  is also lightweight when compared to conventional transfer chambers. As an example, the transfer chamber  100 , made of an aluminum material, weighs less than about 100 lbs (45.4 kg), such as less than about 90 lbs (40.8 kg), without the robot  5  and other peripheral equipment. This light weight promotes mobility by allowing a user to transport the transfer chamber in and around the facility by hand or by using light-duty moving equipment. This is beneficial as the clean room typically includes light-duty moving equipment within the clean room, such as dollies. As a comparison, a typical conventional transfer chamber may weigh no less than between about 250 lbs (113.4) and 600 lbs (272.1 kg), such as about 200 lbs (90.1 kg), thus requiring medium to heavy duty lifting equipment that may not be readily available to the clean room. In this case, the heavier duty equipment must be wiped-down prior to entering the clean room. This results in disruptions in production due to the reduced mobility of the medium to heavy-duty lifting equipment. 
         [0031]    The transfer chamber  100  is also configured to provide a minimal foot print, thus conserving valuable square footage or facilitating use of unused square footage within the facility. For example, the transfer chamber has a plan area less than about 1200 square inches (30.48 square meters), for example about 1000 square inches (25.4 square meters) to about 600 square inches (15.2 square meters), such as about 625 square inches (15.8 square meters) for the transfer chamber  100  shown in  FIG. 1A , while the transfer chamber  200  shown in  FIG. 2  has an area of about 925 square inches (23.5 square meters). To facilitate this small area, the inventors designed the robot  5  to transfer the substrate in the interior volume  4  in a minimal sweep diameter when retracted. 
         [0032]      FIG. 1C  is a schematic top view of one embodiment of a robot  5 . The robot includes an end effector  7  having a substrate  8  thereon, which in this example is a 300 mm semiconductor wafer. The robot  5  is in a retracted position and comprises a first transfer dimension  18 A in this retracted position. In this embodiment, the first transfer dimension is a sweep area, shown as a circle, which is less than about 20 inches (50.8 cm), such as about 19 inches (48.3 cm). The robot  5  is adapted to rotate about an axis wherein no portion of the robot  5  or substrate  8  is outside of the first transfer dimension. The interior volume  4  of the chamber  100  is minimally proportioned to house the robot  5  and allow unimpeded access through each of the substrate transfer ports  10 , and facilitate unimpeded movement of the substrate  8  within the interior volume  4 . This small area of the interior volume  4 , in turn, facilitates the small footprint of the transfer chamber  100 . 
         [0033]      FIG. 1D  is a schematic top view of another embodiment of the robot  5  shown in  FIG. 1C . The robot  5  also includes a second transfer dimension  18 B, which is an extended position. In this embodiment, the extended position (center of rotational axis of robot to center of 300 mm substrate) is between about 700 mm to about 760 mm, for example about 720 mm. In this embodiment, the robot  5  has a minimal first transfer dimension to enable the small footprint for transfer within the transfer chamber  100 , and a second transfer dimension to facilitate transfer of substrates  8  into, out of, the transfer chamber  100 . 
         [0034]    The transfer chamber  100  is configured to form the center of a processing system by providing access and/or a mating connection for a plurality of 200 mm and/or 300 mm process chambers, such as chemical vapor deposition (CVD) chambers, physical vapor deposition (PVD) chambers, plating chambers, atomic layer deposition (ALD) chambers, etch chambers, heat treating chambers, and the like (not shown). The transfer chamber  100  is also configured to couple to peripheral front end modules, such as a load lock chamber, a load/unload module, a wafer cassette assembly, a transfer module, and the like (also not shown). In one embodiment, at least one sidewall  3  is not coupled to a process chamber or front end module so that its substrate transfer port  10  may allow manual loading and unloading of a single substrate  8  directly from a user in the clean room. 
         [0035]    To facilitate coupling to the process chambers and the front end modules, each of the sidewalls  3  may include an interface  6  that accommodates mating of the individual chamber or module to the transfer chamber  100 . The interface  6  may include at least one of a plurality of holes, clamps, a plurality of threaded holes, or a plurality of studs or bolts, or locating pins, adjacent each substrate transfer port  10 . In one embodiment, the interface  6  includes a plurality of indexing pins and a bolt pattern of threaded holes to receive one of a process chamber or a front end module to facilitate coupling to the transfer chamber  100 . In another embodiment, the interface  6  may include an adapter plate  22  ( FIG. 2 ) configured couple to the sidewall  3  and the respective interface  6 . The adapter plate  22  includes an aperture  24  sized to allow transfer of a 200 mm substrate and provides a smaller interface suitable for coupling a 200 mm chamber or module to the transfer chamber  100 . As described above, the arm  5 A ( FIG. 1A ) and end effector  7  of the transfer robot  5  is adapted to extend through the substrate transfer ports  10 , the valves  14 , and the adapter plate  22  to allow additional extension of the robot  5 . The various chambers and modules are sealed with the transfer chamber  100  by O-rings or any other sealing method to prevent vacuum leakage. 
         [0036]      FIG. 2  is an exploded isometric view of another embodiment of a transfer chamber  200 . The transfer chamber  200  is similar to the transfer chamber  100  shown in  FIGS. 1A ,  1 B, and like reference numerals are included to denote similar elements. The transfer chamber  200  in this embodiment includes a depression  19  formed in a lower surface  16  of the transfer chamber  200 . The depression  19  is configured to receive an elevator assembly  21  adapted to facilitate transfer of substrates. In one embodiment, the depression  19  is a recess formed in the lower surface  16  sized to receive the elevator assembly  21 . In another embodiment, the depression  19  is an opening formed through the lower surface  16  sized to receive the elevator assembly  21 , wherein a portion of the elevator assembly  21  is adapted to seal the depression  19 . The elevator assembly  21  is a removable assembly configured to support a plurality of substrates. In one embodiment, the elevator assembly  21  comprises a wafer cassette, and a vertical drive is coupled to the cassette in a manner that the cassettes&#39; elevation within the transfer chamber is controlled. The vertical drive is configured to move the cassette in a vertical direction, thus selectively aligning each substrate disposed in the cassette with respect to the transfer plane of the robot  5 . In this manner, a substrate may be provided by the elevator assembly  21  and returned to the elevator assembly after processing. When the substrate has been returned to the elevator assembly  21 , the elevator assembly may be actuated upward or downward to align the next substrate in the queue with the robot  5 , and the queued substrate may be processed similarly and returned to the elevator assembly  21 . 
         [0037]    The lid  9  includes a cover  23  sized to house an upper portion of the elevator assembly  21  and in one embodiment, includes at least one view port  25  to monitor the interior volume  4 . In this embodiment, a vacuum pump  17  is shown coupled to the port  15  and the mainframe  11 . A tray  13  is coupled to the mainframe  11  below the transfer chamber  200  and may be used to support system controllers that control transfer sequences, a pneumatic device, such as a pneumatic controller, and a compressed air supply used by the transfer chamber  200  or other modules coupled thereto. The transfer chamber  200  also includes at least one external valve  26  to facilitate substrate transfer into the chamber  200  or elevator assembly  21  from the exterior of the chamber  200 . 
         [0038]      FIG. 3  is a schematic view of one embodiment of a modular processing system  30 . The modular processing system  30  includes a transfer chamber  1 , which may be the transfer chamber  100  or  200  as described above, or other suitable transfer chamber, having a plurality of process chambers  29  coupled to the sidewalls  3  of the transfer chamber  1 . At least one of the sidewalls  3  is adapted to couple to a front end module  27  such as a load lock chamber, a load/unload module, a wafer cassette assembly, a transfer module, and the like. The process chambers  29  may be an assortment of process chambers available from Applied Materials, Inc. of Santa Clara, Calif. Some examples of process chambers  29  may be ALD chambers, CVD chambers, PVD chambers, and the like. Examples of front end modules  27  include single wafer load lock chambers and dual single wafer load lock chambers available from Applied Materials, Inc. It is also contemplated that the transfer chamber  1  may be configured to couple to process chambers and front end modules from other manufacturers. 
         [0039]      FIG. 4  is a schematic view of another embodiment of a modular processing system  40 . The modular processing system  40  includes a first transfer chamber  1 A having a front end module  27  coupled to sidewall  41  to provide substrates (not shown) to the transfer chamber  1 A. A substrate may be transferred to process chambers  29  coupled to sidewalls  42  and  44  or may be transferred to a transfer module  31  coupled to sidewall  43 . The transfer module  31  is coupled to sidewall  45  of a second transfer chamber  1  B which facilitates transfer between the transfer chambers  1 A and  1 B. The transfer module  31  includes a substrate support and/or lift pins suitable for facilitating handoff between robots in the adjacent transfer chambers  1 A,  1 B. 
         [0040]    In the embodiment depicted in  FIG. 4 , the transfer module  31  includes a substrate support (not shown) having a plurality of pins extending upward. The plurality of pins define a substantially planar and horizontal support surface for supporting a substrate and are spaced to allow the end effector of the robot to be inserted between the pins. Once the substrate has been transferred to the transfer module  31 , the substrate may be transferred to a plurality of process chambers  29  coupled to sidewalls  46 - 48 . The substrate may be processed in this travel route in one or a plurality of chambers  29  coupled to the first and second transfer chambers  1 A and  1 B, and return to the front end module  27  through the transfer module  31 . Alternatively, any one of the plurality of process chambers  29  coupled to the second transfer chamber  1 B may be replaced with a front end module  27  (not shown). 
         [0041]    In one embodiment, the transfer module  31  is configured to enable a staged vacuum between transfer chambers  1 A and  1 B. For example, transfer chamber  1 A may be pumped down to a pressure of about 10 −5  Torr (133.3 mPa) and the transfer chamber  1 B may be pumped to a pressure of about 10 −8  Torr (1.33 pPa). 
         [0042]    As has been shown, the transfer chambers  100  and  200  and the processing chamber configurations shown in  FIGS. 3 and 4 , provide adaptation for many different system layouts as determined by the geometry of the clean room or by user preference. The compact, lightweight design and modularity provided by the transfer chambers described herein provide unlimited portability of a processing system. Once a space or site within the facility has been chosen, plumbing, electrical, and the like, may be provided to the site from central facility sources (if needed), and the transfer chamber may be brought into the facility without the use of heavy lifting devices as described above. The robot, and other peripheral parts, may be brought into the facility and assembled at the site and coupled to the plumbing and electrical. One or more process chambers, and/or a front end device, may be brought into the facility and coupled to the transfer chamber and plumbing to define a processing system having one or more processing chambers. The resulting processing system described above requires minimal capital outlay and minimal to no disruption of the facility. The processing system may then be calibrated, and a process may then be run in the system without the need to take a production tool off-line. 
         [0043]    As an example, a user may build a small R&amp;D processing system in an unused corner of a clean room by purchasing the transfer chamber and at least one process chamber  29 , and after plumbing, the user may begin running processes using hand loaded substrates placed on the end effector  7  by the user. The user may then want to expand by purchasing another one or more process chambers  29 , which may require a second or third transfer chamber. The R&amp;D system may now be a full production tool within the corner of the clean room defining a straight line as shown in  FIG. 4  (with two transfer chambers  1 A,  1 B), or the geometry of the clean room may require a 90 degree turn to make an L shaped processing system in the case of more than two transfer chambers (not shown). In this example, process chamber  29  on sidewall  45  or sidewall  48  may be replaced with a transfer module  31  to facilitate transfer between transfer chamber  1 B and the third transfer chamber (not shown). Additionally, the user may combine additional transfer modules  31  and additional transfer chambers for adding more process chambers  29 . 
         [0044]      FIG. 5  is an isometric view of another embodiment of a processing system  50  above a clean room floor  52 . The processing system  50  includes a transfer chamber  1 , which is transfer chamber  200  as shown in  FIG. 2 . The transfer chamber  1 , supported by the mainframe  11 , is shown coupled to three process chambers  29 . System boxes  54 , if necessary or preferred for the process chambers  29 , may be positioned below the respective process chamber  29  in order to make the processing system more compact. The system boxes  54  may include process controllers such as pneumatic devices, and gas valving and controls for a process chamber. Dedicated gas boxes  56 , for supplying processing materials such as gasses and chemicals, may be dollied and positioned adjacent the transfer chamber  1  if processing materials are not supplied and plumbed from central facility sources through the clean room floor  52 . Power to run the processing system  50  may be provided by any power supply available, such as a remote power box  58 . Each process chamber  29  may receive temperature controlled water from a dedicated heat exchanger  60 . Exhaust may be individually plumbed to specific abatement systems and the roughing is provided by exhaust pumps  62 . High level control of the transfer chamber  1  and the processing system is provided by a computer  64  having a touch screen monitor adjacent the transfer chamber  1 . 
         [0045]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.