Patent Publication Number: US-2022223367-A1

Title: Reduced substrate process chamber cavity volume

Description:
BACKGROUND 
     Field 
     Embodiments of the present invention generally relate to a semiconductor processing chamber, and more particularly to semiconductor processing chambers having a small processing volume. 
     Description of the Related Art 
     Substrate processing chambers for processes such as with a reactive physical vapor deposition (PVD) process, an atomic layer deposition (ALD) process, a chemical vapor deposition (CVD) process, an etch process, a thermal process, a plasma ion implant process, reactive gas process, or other processes, conventionally have relatively large processing volumes. In addition to the volume of a processing space adjacent to a substrate being processed, the entirety of a conventional processing volume includes a volume beneath the substrate support, that typically includes ports for vacuum pumps and inlets for one or more gases used in processing and/or cleaning the chamber. Conventionally, such processing volumes may exceed 40 liters, most of which is not part of the processing space. 
     As a result of a relatively large processing volume, conventional processing chambers are expensive to operate. Sufficient amounts of gas that may be required for substrate processing fill not only the processing space but the processing volume, resulting in significant amounts of gas that are unused and discarded after a processing cycle. 
     Moreover, due to relatively large processing volumes, substrate processing time is increased as well. At scale, pumping times needed to fill a chamber with enough gas, and subsequent evacuation of that gas after processing may take 15 seconds or more for a full processing cycle for a substrate. Over thousands of substrates, the time needed to fill and evacuate a chamber is significant. 
     What is needed are systems and apparatus to overcome the deficiencies of conventional approaches. 
     SUMMARY 
     Certain embodiments generally related to an apparatus for processing a substrate are disclosed that include a shield, a process kit support, and a substrate support. These embodiments include a process volume defined by the shield and the process kit support having a volume of 20 liters or less, and an upper gas inlet positioned above the substrate support in fluid communication with a gas source. 
     Further embodiments disclose an apparatus for processing a substrate that include a target, and a substrate support positioned 40 mm or less from the target. These embodiments include a process volume containing the substrate support, the process volume defined by a shield and a process kit support of less than 20 liters, and a plurality of gas inlets, a first one of the plurality of gas inlets positioned adjacent to the target, and a second one of the plurality of gas inlets positioned adjacent to the substrate support. 
     In further embodiments an apparatus for processing a substrate is disclosed, that includes a shield, and a process kit support. Such embodiments further include a process volume defined by the shield and process kit support, and a pump coupled to the process volume, configured to cycle pressure of the process volume from a pre-process pressure to a process pressure and back to the pre-process pressure in less than 5 seconds. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, 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 exemplary embodiments and are therefore not to be considered limiting of its scope, and the disclosure may admit to other equally effective embodiments. 
         FIG. 1  is a plan view of a cluster tool assembly according to certain embodiments. 
         FIG. 2  is a plan view of a cluster tool assembly having a plurality of transfer chamber assemblies, according to certain embodiments. 
         FIG. 3  depicts a semiconductor processing assembly according to certain embodiments. 
     
    
    
     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 and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
     DETAILED DESCRIPTION 
     In the following, reference is made to embodiments of the disclosure. However, it should be understood that the disclosure is not limited to specifically described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the disclosure. Furthermore, although embodiments of the disclosure may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the disclosure. Thus, the following aspects, features, embodiments, and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, a reference to “the disclosure” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). 
     Aspects of the present disclosure relate to systems and apparatuses for a substrate processing assembly with a low processing volume. In disclosed embodiments, a processing volume may include a processing space adjacent to a substrate being processed on a substrate support as well as a volume of the processing chamber surrounding and below the substrate support. In some embodiments, the total processing volume is 15 liters or less in certain embodiments, resulting in lower gas usage and faster processing times than conventional approaches. In some embodiments, the distance between the substrate and a target, electrode, chamber lid, or showerhead face is 35 mm or less in certain embodiments. In certain embodiments, the processing chamber has a dedicated pump for pumping the chamber to a processing pressure as well as evacuating the chamber after processing of the substrate. 
     Embodiments of the present disclosure are directed towards apparatus for substrate processing and a cluster tool including a transfer chamber assembly and a plurality of processing assemblies. The transfer chamber assembly and processing assemblies may include processing platforms for ALD, CVD, PVD, etch, cleaning, implanting, heating, annealing, and/or polishing processes. Other processing platforms may also be used with the present disclosure. The present disclosure generally provides a substrate processing tool with increased process condition flexibility between process assemblies within the same cluster tool. 
     In conventional approaches, substrate processing assemblies have relatively large processing volumes, including a processing space adjacent to a substrate support, as well as a substantially lower volume beneath the substrate support. Conventionally, gas is provided to the processing space by injecting into the lower volume, and once full, the gas moves into the processing space. As conventional volumes may exceed 40 liters, a substantial amount of processing gas is required fill the processing volume with processing gas, most of which is not used. Moreover, evacuating the process volume and pumping the processing volume down to a processing pressure may take a substantial amount of time. The entire process to fill a substrate processing assembly with gas, evacuate the used gases, pump down, and refill may take 15 seconds or longer. 
     Conventionally, the primary way to control gas flow from the lower volume to the processing space is by moving the substrate support relative to an electrode, thereby changing an annular gap coupling the lower volume and the processing space. 
     According to systems and apparatuses disclosed herein, a reduced processing volume is provided, being 20 liters or less, and in some embodiments, 15 liters or less. One or more gases may be provided directly to a processing space by an upper gas inlet located between an upper shield and an electrode, as well as from a lower processing volume via an annular gap formed between a lower shield and a substrate holder. By enabling injection of gas directly to a processing space from the upper gas inlet, disclosed embodiments may adjust the height of the substrate support to any desired distance from the electrode. Moreover, a pumpdown pump dedicated to a single substrate processing assembly is provided. By providing a reduced processing volume and dedicated pumpdown, pump cycling time for processing a substrate according to disclosed embodiments may take less than 5 seconds in some embodiments and less than 3 seconds in certain embodiments. 
     By providing rapid pump cycling of the substrate processing assembly, certain embodiments further include the ability for the substrate processing assembly to perform self a self-cleaning process. In conventional approaches with 40 liter process volumes, self-cleaning would require too much time to exhaust the chamber, pump up to the required pressure, introduce reactive or non-reactive cleaning gases, and pump down to efficiently clean a chamber as part of a manufacturing process. By using embodiments disclosed herein, a cleaning process may be efficiently performed as pump cycling the substrate processing assembly may be done in under 15 seconds. 
     The present disclosure includes embodiments for substrate processing. A substrate and optionally a support chuck may be transported between processing assemblies within a transfer volume formed by a transfer chamber assembly. The processing assemblies include processing volumes in which the substrate is processed. The support chuck may optionally detach from a lift assembly while being transported between processing assemblies. When the substrate and the support chuck are disposed on the lift assembly, the lift assembly raises the substrate and support chuck to an upper processing position. While in the upper processing position, surfaces of the processing assembly and the support chuck seal against one another to form a fluidly isolated processing volume. The processing volume is fluidly isolated from the transfer volume formed by the transfer chamber assembly. 
     The isolation of the processing volume from the transfer volume by the movement of the lift assembly allows for each of the processing volumes to be adjusted to different pressures. This enables different substrate processing steps to be performed within each of the processing assemblies within the transfer chamber assembly, even when each processing step requires different pressures and temperatures. The use of the support chuck as the sealing member within the processing assembly also minimizes the volume of the processing volume. Minimizing the processing volume decreases the amount of process gases and purge gases required during each process. The sealing between each processing volume and the transfer volume additionally minimizes process gas leakage into the transfer chamber. The apparatus and method utilized to create the seal between the processing volumes and the transfer volume minimize particle contamination within the processing volumes and decrease downtime of the apparatus caused by part replacement and cleaning. 
       FIGS. 1 and 2  are plan views of cluster tool assemblies  100 ,  200  with transfer chamber assemblies  150  and substrate processing assemblies  160  as described herein. The cluster tool assembly  100  of  FIG. 1  includes a single transfer chamber assembly  150  and a plurality of front end robot chambers  180  between the transfer chamber assembly  150  and load lock chambers  130 . The cluster tool assembly  200  of  FIG. 2  includes multiple transfer chamber assemblies  150  and a buffer chamber  203  disposed between the transfer chamber assemblies  150  and load lock chambers  130 . 
     In  FIG. 1 , the cluster tool assembly  100  includes Front Opening Unified Pods (FOUPs)  110 , a Factory Interface (FI)  120  adjacent to and operably connected to the FOUPs  110 , load lock chambers  130  adjacent to and operably connected to the FI  120 , front end robot chambers  180  adjacent to and operatively connected to the load lock chambers  130 , prep chambers  190  adjacent to and operatively connected to the front end robot chambers  180 , and a transfer chamber assembly  150  connected to the front end robot chambers  180 . 
     The FOUPs  110  are utilized to safely secure and store substrates during movement thereof between different substrate processing equipment, as well as during the connection of the FOUPs to the substrate processing equipment while the substrates are disposed therein. The number of FOUPs  110  (four shown) may vary in quantity depending upon the processes run in the cluster tool assembly  100 . The throughput of the cluster tool assembly  100  also, at least in part, defines the number of docking stations on the FI  120  to which the FOUPs are connected for the unloading of substrates therefrom and the loading of substrates thereinto. The FI  120  is disposed between the FOUPs  110  and the load lock chambers  130 . The FI  120  creates an interface between a semiconductor fabrication facility (Fab) and the cluster tool assembly  100 . The FI  120  is connected to the load lock chambers  130 , such that substrates are transferred from the FI  120  to the load lock chambers  130  and from the load lock chambers  130  and into the FI  120 . 
     The front end robot chambers  180  are located on the same side of each of the load lock chambers  130 , such that the load lock chambers  130  are located between the FI  120  and the front end robot chambers  180 . The front end robot chambers  180  each include a transfer robot  185  therein. The transfer robot  185  is any robot suitable to transfer one or more substrates from one chamber to another, through or via the front end robot chamber  180 . In some embodiments, as shown in  FIG. 1 , the transfer robot  185  within each front end robot chamber  180  is configured to transport substrates from one of the load lock chambers  130  and into one of the prep chambers  190 . 
     The prep chambers  190  may be any one of a pre-clean chamber, an anneal chamber, or a cool down chamber, depending upon the desired process within the cluster tool assembly  100 . In some embodiments, the prep chambers  190  are plasma clean chambers. In yet other exemplary embodiments, the prep chambers  192  are Preclean II chambers available from Applied Materials, Inc., of Santa Clara, Calif. A vacuum pump  196  is positioned adjacent to each of the prep chambers  192 . The vacuum pumps  196  are configured to pump the prep chambers  190  to a predetermined pressure. In some embodiments, the vacuum pump  196  is configured to decrease the pressure of the prep chamber  192 , such as to create a vacuum within the prep chamber  192 . 
     As shown in  FIG. 1 , two load lock chambers  130 , two front end robot chambers  180 , and two prep chambers  190  are configured within the cluster tool assembly  100 . The two load lock chambers  130 , the two front end robot chambers  180 , and the two prep chambers  190 , when arranged as shown in  FIG. 1  and described above, may form two transport assemblies. The two transport assemblies may be spaced from each other and may form mirror images of one another, such that the prep chambers  190  are on opposite walls of their respective front end robot chambers  180 . 
     The transfer chamber assembly  150  is adjacent to, and operatively connected to, the front end robot chambers  180 , such that substrates are transferred between the transfer chamber assembly  150  and front end robot chambers  180 . The transfer chamber assembly  150  includes a central transfer device  145  and a plurality of substrate processing assemblies  160  therein. The plurality of substrate processing assemblies  160  is disposed around the central transfer device  145 , radially outward of a pivot or central axis of the central transfer device  145  in the transfer chamber assembly  150 . 
     A chamber pump  165  is disposed adjacent to, and in fluid communication with, each of the substrate processing assemblies  160 , such that there is a plurality of chamber pumps  165  disposed around the central transfer device  145 . The plurality of chamber pumps  165  are disposed radially outward of the central transfer device  145  in the transfer chamber assembly  150 . As shown in  FIG. 1 , one chamber pump  165  is fluidly coupled to each of the substrate processing assemblies  160 . 
     In some embodiments, there may be multiple chamber pumps  165  fluidly coupled to each substrate processing assembly. In yet other embodiments, one or more of the substrate processing assemblies  160  may not have a chamber pump  165  directly fluidly coupled thereto. In some embodiments, a varying number of chamber pumps  165  are fluidly coupled to each substrate processing assembly  160 , such that one or more substrate processing assemblies  160  may have a different number of chamber pumps  165  than one or more other substrate processing assemblies  160 . The chamber pumps  165  enable separate vacuum pumping of processing regions within each substrate processing assembly  160 , and thus the pressure within each of the processing assemblies may be maintained separately from one another and separately from the pressure present in the transfer chamber assembly  150 . 
       FIG. 1  depicts an embodiment having six substrate processing assemblies  160  within the transfer chamber assembly  150 . However, other embodiments may have a different number of substrate processing assemblies  160  within the transfer chamber  150 . For example, in some embodiments, two to twelve substrate processing assemblies  160  may be positioned within the transfer chamber assembly  150 , such as four to eight substrate processing assemblies  160 . In other embodiments, four substrate processing assemblies  160  may be positioned within the transfer chamber assembly  150 . The number of substrate processing assemblies  160  impacts the total footprint of the cluster tool  100 , the number of possible process steps capable of being performed by the cluster tool  100 , the total fabrication cost of the cluster tool  100 , and the throughput of the cluster tool  100 . 
     Each of the substrate processing assemblies  160  can be any one of PVD, CVD, ALD, etch, cleaning, heating, annealing, and/or polishing platforms. In some embodiments, the substrate processing assemblies  160  are all one type of processing platform. In other embodiments, the substrate processing assemblies  160  includes two or more different processing platforms. In one exemplary embodiment, all of the substrate processing assemblies  160  are PVD process chambers. In another exemplary embodiment, the substrate processing assemblies  160  includes both PVD and CVD process chambers. The plurality of substrate processing assemblies  160  can be altered to match the types of process chambers needed to complete a semiconductor fabrication process. 
     The central transfer device  145  is disposed at generally the center of the transfer chamber assembly  150 , such that a central axis  155  of the transfer chamber assembly  150  is disposed through the central transfer device  145 . The central transfer device  145  is any suitable transfer device configured to transport substrates between each of the substrate processing assemblies  160 . In one embodiment, the central transfer device  145  is a central robot having one or more blades configured to transport substrates between each substrate processing assembly  160 . In another embodiment, the central transfer device is a carousel system by which processing regions are moved along a circular orbital path centered on the central axis  155  of the transfer chamber assembly  150 . 
       FIG. 2  is a plan view of the cluster tool  200  with multiple transfer chamber assemblies  150  connected thereto. The FOUPs  110 , FI  120 , and load lock chambers  130  may be arranged similarly to the FOUPs  110 , FI  120 , and load lock chambers  130  described above in relation to  FIG. 1 . The cluster tool  200  of  FIG. 2  further includes an FI etch apparatus  115 , a buffer chamber  203 , and a plurality of transfer chamber assemblies  150 . 
     The FI etch apparatus  115  is positioned adjacent to the FI  120 , such that the FI etch apparatus  115  is disposed on a side wall of the FI  120 . The FI etch apparatus  115  may be positioned on a side wall of the FI  120  that is separate from the side walls of the FI that are connected to the FOUPs  110  and the load lock chambers  130 . The FI etch apparatus  115  may be an etch chamber. The FI etch apparatus  115  may be similar to the Centris® line of etch chambers available from Applied Materials, Inc. 
     The buffer chamber  203  is located between the load lock chambers  130  and the plurality of transfer chamber assemblies  150  and provides an isolatable volume through which substrates may be transferred among and between the load lock chambers  130  and the multiple transfer chamber assemblies  150 . The buffer chamber  203  is coupled to both the load lock chambers  130  and the plurality of transfer chamber assemblies  150 . As shown in  FIG. 2 , three transfer chamber assemblies  150  are disposed around and attached to the buffer chamber  203 . In other embodiments, there may be one, two, or more than three transfer chamber assemblies  150  disposed around the buffer chamber  203 . 
     The buffer chamber  203  includes at least one opening  209  along each wall of the buffer chamber  203  that is in contact with a transfer chamber assembly  150  or a load lock chamber  130 . Each of the openings  209  is sized to allow the passage of a substrate, a substrate chuck, or a substrate on a substrate chuck to and from the transfer chamber assemblies  150 . In some embodiments, there are two openings  209  along each wall of the buffer chamber  203  that is adjacent to the transfer chamber assemblies  150 . This allows for the passage of two substrates to the transfer chamber assemblies  150  from the buffer chamber  203  or from the transfer chamber assemblies  150  to the buffer chamber  203  simultaneously. 
     The buffer chamber  203  includes one or more buffer chamber transfer robots  206 . The buffer chamber transfer robots  206  move substrates, chucks, or both substrates and chucks between the transfer chamber assemblies  150  and the load lock chambers  130 . The buffer chamber transfer robots  206  may be any suitable substrate transfer robot. 
     To enable isolation of the buffer chamber  203  internal volume from process gases used in the process assemblies  160  of the transfer chamber assemblies  150 , access between each transfer chamber assembly  150 , and the openings  209  in the buffer chamber  203  are selectively sealed by a respective fluid isolation valve, such as a slit valve. The fluid isolation valves (not shown) are disposed within the wall of each of the transfer chamber assemblies  150 , the wall of the buffer chamber  203 , or as a separate assembly between the buffer chamber  203  and the transfer chamber assembly  150 . Additionally, the fluid isolation valves may include a plate and seal assembly which is pressed by a selectively operable ram to selectively cover and seal, or uncover, the respective opening  209 . The plate and seal assembly thereby selectively seals, or allows, fluid communication between the transfer chamber assembly  150  and the buffer chamber  203  and also allows, when retracted away from an opening  209 , a support blade or end effector on the buffer chamber transfer robot  206  in the buffer chamber  203  to transport a substrate through the opening  209 . 
     The transfer chamber assemblies  150  may be configured the same as the one described above in relation to  FIG. 1 . This includes the placement and structure of the central transfer devices  145 , the plurality of substrate processing assemblies  160 , and the chamber pumps  165  within each of the transfer chamber assemblies  150 . However, alternative embodiments of the transfer chamber assemblies  150  may be utilized. 
     Example Embodiments of a Reduced Volume Substrate Processing Assembly 
       FIG. 3  depicts a semiconductor processing assembly  300  according to certain embodiments. A processing volume  303  of the substrate processing assembly  300  includes a volume defined by a shield  306  and a process kit support  309 . In certain embodiments, the processing volume  303  may be further defined by a sealing plate  312  and/or a top plate of a bellows  315 . 
     The processing volume  303  includes a process space  318  located between a substrate support  321  and an opposing surface located opposite the substrate support  321  and a lower processing volume  359  below the substrate support  321  and shield  306 . In certain embodiments, the opposing surface may be a target  324 , while in other embodiments, the opposing surface may be an electrode  327 . In certain embodiments, substrate support  321  may include a cover ring  356 . Although the embodiment shown in  FIG. 3  depicts an embodiment utilizing an electrode and a target, it will be appreciated by one of skill in the art that the disclosure herein may be applicable to different types of semiconductor processing chambers. In this context, the opposing surface may be a showerhead (not shown), a chamber lid enclosing the process volume, or other components of a substrate processing assembly  300  providing an opposing surface opposite the substrate support  321 . Although a variety of opposing surfaces are contemplated herein, the target  324  will be discussed. In certain embodiments the processing volume  303  has a volume of 20 liters, and in some embodiments is 15 liters or less. 
     The processing volume  303  may be further defined by distances between various components of the substrate processing assembly  300 . In some embodiments, a distance between the substrate support  321  and the target  324  may be 150 mm or less, and in some embodiments, this distance may be 35 mm or less. The processing volume  303  may be further defined by a distance between a bottom surface of the shield  306  and one of the process kit support  309  and sealing plate  312 . In some embodiments, this distance may be 1 inch or less, while in other embodiments, this distance may be as low as 0.150 inches or less. In certain embodiments, the sealing plate  312  may be sealingly coupled to the process kit support  309  by an upper seal  350  and to the bellows  315  by a lower seal  353 . 
     The shield  306  includes an upper shield  330  and a lower shield  333 . The upper shield  330  is that portion of the shield  306  adjacent to the electrode  327  and target  324 . In some embodiments, one or both of the electrode  327  and target  324  may be replaced by a showerhead or other lid assembly of the substrate processing assembly  300 . A space between the upper shield  330  and one of the target  324  and electrode  327  defines an upper gas inlet  336  for providing one or more gases into the process space  318  of the processing volume. The upper gas inlet  336  is in fluid communication with the process space  318  as well as one or more gas sources  356  that provide one or more gases via the upper gas inlet  336 . The substrate processing assembly  300  further includes a dielectric ring  338 , disposed on the shield  306 , between the upper shield  330  and the electrode  327 . 
     The lower shield  333  extends from the upper shield  330 , forming an opening in which is positioned the substrate support  321 . Between the substrate support  321  and the lower shield  333  is an annular gap defining a lower gas inlet  341  through which one or more gases may be provided to the process space  318  from a gas inlet  344 . Both the lower gas inlet  341  and upper gas inlet  336  may provide a variety of gases to the processing volume  303 , including gases to be developed into a plasma in the processing volume  303  or remotely developed into a plasma and subsequently delivered to the processing volume  303 . The lower gas inlet  341  may further serve as a pathway for one or more gases to be exhausted from the process space  318 , via a pump down passage  347  coupled to a vacuum pump  354 , and coupled to a single substrate processing assembly, such as substrate processing assembly  300 . Pump down passage  347  may further serve to provide a low pressure environment to the processing volume  303 , such as 20 mTorr to as low as 10-{circumflex over ( )}8 Torr. 
     By providing a dedicated vacuum pump coupled to pump down passage  347 , which in certain embodiments is an 80 liter turbopump, the processing volume  303  is fully cycled (introduce processing gases, brought to a desired pressure, evacuated) in 5 seconds or less and in some embodiments in 3 seconds. In this context, dedicated indicates that the vacuum pump services a single substrate processing assembly and is not coupled to multiple substrate processing assemblies, according to certain embodiments. As substrate processing assembly  300  may be fully cycled in a short amount of time, a chamber cleaning process may be used in the substrate processing assembly  300 , fully cycling the pressure and introducing one or more reactive/non-reactive cleaning gases. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.