Patent Publication Number: US-2023160101-A1

Title: Apparatus and methods for reducing substrate cool down time

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 63/281,301, filed Nov. 19, 2021, the entirety of which is herein incorporated by reference. 
    
    
     BACKGROUND 
     Field 
     Embodiments of the present disclosure generally relate to apparatus and methods for processing a substrate. More specifically, the disclosure is directed towards apparatus and methods for improving throughput of a substrate during semiconductor manufacturing processes. 
     Description of the Related Art 
     Many applications in semiconductor manufacturing utilize the deposition of one or more epitaxy layers. Epitaxial deposition is a relatively slow process which challenges throughput. 
     As technology evolves, the power device process landscape for epitaxial deposition applications is changing. Current trends favor thinner epitaxial layers and running a substrate through multiple deposition operations between each substrate cleaning operation. 
     Reduced epitaxial layer thickness has been shown to shift the limiting time factor from the epitaxial deposition operation itself to the substrate loading and unloading operations. In some instances, one or more process chambers are left unused for prolonged periods of time due to delays in loading/unloading substrates. 
     Therefore, what is needed are improved loading/unloading mechanisms and methods for improving throughput. 
     SUMMARY 
     In one embodiment, a method of processing a substrate, suitable for use in semiconductor manufacturing, is described. The method includes removing a first substrate from a processing chamber using a transfer robot with two or more arms, moving the first substrate into a transfer chamber, moving the first substrate into a cool-down chamber, determining a wait time of the first substrate within the transfer chamber, determining a cool down factor dependent on the wait time, and determining an adjusted cool down time using the cool down factor and a determined original cool down time. 
     In another embodiment, a method of processing a substrate, suitable for use in semiconductor manufacturing, is described. The method includes process operations of (a) removing a first substrate from a processing chamber using a first arm of a transfer robot, (b) moving the first substrate into a transfer chamber, (c) moving a second substrate on a second arm of the transfer robot into the processing chamber, (d) moving the first substrate into a cool-down chamber, (e) determining a wait time of the first substrate on the first arm within the transfer chamber, (f) determining a cool down factor dependent on the wait time, and (g) determining an adjusted cool down time using the cool down factor and a determined original cool down time. 
     In another embodiment, a processing system, suitable for use during semiconductor processing, is described. The processing system includes a transfer chamber comprising a transfer robot having a first arm and a second arm, a plurality of processing chambers coupled to the transfer chamber, one or more cool-down chambers, and a controller storing instructions. The stored instructions within the controller enable process operations of: removing a first substrate from one of the plurality of processing chambers using a first arm of the transfer robot, moving the first substrate into the transfer chamber, moving the first substrate into the cool-down chamber, determining a wait time of the first substrate within the transfer chamber, determining a cool down factor dependent on the wait time, and determining an adjusted cool down time using the cool down factor and a determined original cool down time. 
    
    
     
       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, may admit to other equally effective embodiments. 
         FIG.  1    is a schematic plan view of a processing system, according to one or more embodiments. 
         FIG.  2    is a schematic cross-sectional view of a processing chamber that may be used to perform deposition processes, according to one or more embodiments. 
         FIG.  3    is a schematic cross-sectional view of a cool-down chamber, according to one or more embodiments. 
         FIGS.  4 A- 4 B  are schematic views of a transfer robot, according to one or more embodiments. 
         FIG.  5    illustrates a method of cooling a substrate, according to one or more embodiments. 
         FIG.  6    illustrates a graph of substrate cool-down times as related to wait times, according to one or more 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 
     The present disclosure is directed towards apparatus and methods for reducing backlog of substrates within a processing system. More specifically, the present disclosure is directed towards apparatus and methods for reducing substrate cool-down times within a cool-down chamber. As the amount of time the substrate is being processed within a process chamber has decreased, the amount of time to load and unload a substrate from the process chamber has become a limiting factor. The implementation of a transfer robot with two or more substrate handlers reduces the amount of loading and unloading time. As the loading and unloading time has decreased, the time a substrate is cooled within a cool down chamber has become a limiting factor in overall substrate throughput within the processing system. 
     In embodiments wherein the transfer robot is configured to hold two substrates, a first substrate is unloaded from a process chamber using a first handler arm, while a second substrate is held by a second handler arm. The first substrate is hot while being removed from the process chamber. Once the first substrate is unloaded from the process chamber, the second substrate is inserted into the process chamber. While the second substrate is being inserted into the process chamber, the first substrate is idle on the first arm. Once the second substrate has been loaded into the process chamber, the first substrate is then inserted into a cool-down chamber. The cool-down chamber performs a cooling process on the first substrate while the second substrate is processed within the process chamber. In some embodiments, the amount of time the second substrate is within the processing chamber is less than the amount of time the first substrate is within the cool-down chamber. Additional substrates are also processed in additional process chambers attached to the processing system. The cool-down chamber also serves as an exit path from the processing system. Therefore, as additional substrates are processed in each of the process chambers, the wait time for the substrates to be inserted into and cooled by the cool-down chamber causes a backlog within the processing system. 
     As discussed herein, cool down time within a processing system is regulated, such that each substrate is disposed within the cool-down chamber for a pre-determined time. The pre-determined time may be a minimum time which increases based off of temperature measurements within the cool-down chamber. The pre-determined time enables cooling of the substrate to below a pre-determined temperature before being unloaded from the cool-down chamber. The cool-down time may be a pre-set value time of about 60 seconds to about 80 seconds, such as about 65 seconds to about 75 seconds. Embodiments described herein provide methods for reducing the pre-determined time on an individualized substrate basis and improving the overall throughput of the processing system. 
     The cool-down time of substrates passing through the cool-down chamber may be reduced by accounting for the wait time of each substrate on the handler arm of the transfer robot. As the first substrate is held by the handler arm after being removed from the process chamber, the first substrate is cooled within the transfer chamber. The hot substrate dissipates heat into the transfer chamber volume, such that the temperature of the substrate is reduced while positioned in the transfer chamber. 
     The cooling of the substrate is a byproduct of the temperature and gas flow conditions within the transfer chamber volume of the transfer chamber. In some embodiments, the transfer chamber includes a constant nitrogen purge, such that the transfer chamber volume is filled with the nitrogen purge gas and the temperature of the nitrogen purge gas within the transfer chamber volume and surrounding the substrate is relatively constant. The amount of time the first substrate is held by the handler arm before being transferred into the cool-down chamber varies for each substrate processed within the processing system. The variability of the wait times on the handler arm varies depending on the processing sequences within other portions of the processing system. By tracking the amount of time each substrate waits on a handler arm of the transfer robot within the transfer chamber, the cool-down time for each substrate may be individually adjusted and reduced. 
     A controller within the processing system is configured to determine the wait time within the transfer chamber of each of the hot substrates after the substrates are extracted from the processing chamber. The wait times may also be estimated from historical processing data or process simulations. The wait time is utilized to reduce the overall cool-down time within each cool-down chamber. As described herein, the wait time determined by the controller is multiplied by a cooling variable, such as a safety factor, to determine a cool-down factor. The cooling variable may be about 0.5 to about 1.0, such as about 0.6 to about 0.8, such as about 0.6 to about 0.7. The cool-down factor is an estimated reduction in cool-down time. The cool-down factor is subtracted from the overall cool-down time within the cool-down chamber to form an adjusted cool-down process. The overall cool-down time may be the pre-determined cool down time. The adjusted cool-down process has a generally lower cool-down time per substrate compared to the overall cool-down time if the cool-down factor was not compensated for. The adjusted cool-down process has been shown to increase overall throughput of the processing system. In some embodiments, the throughput improvement caused by accounting for cooling within the transfer chamber improves the throughput of the processing system by up to 10%. Utilization of the methods described herein may therefore increase overall throughput while not increasing processing costs. 
       FIG.  1    is a schematic plan view diagram of an example of a semiconductor processing system  100  according to one or more embodiments. The processing system  100  generally includes a factory interface  102 , load lock chambers  104 ,  106 , a transfer chamber  116  with a transfer robot  118 , and processing chambers  124 ,  126 ,  128 ,  130 . As detailed herein, substrates in the processing system  100  can be processed in and transferred between the various chambers without being exposed to an ambient environment exterior to the processing system  100 . For example, substrates can be processed in and transferred between the various chambers in a low pressure (e.g., less than or equal to about 300 Torr) or vacuum environment without breaking the low pressure or vacuum environment between various processes performed on the substrates in the processing system  100 . Accordingly, the processing system  100  may provide for an integrated solution for some processing of substrates. 
     Examples of a processing system that may be suitably modified in accordance with the disclosure provided herein include the Endura®, Producer® or Centura® integrated processing systems or other suitable processing systems commercially available from Applied Materials, Inc., located in Santa Clara, Calif. It is contemplated that other processing systems (including those from other manufacturers) may be adapted to benefit from aspects described herein. 
     In the illustrated example of  FIG.  1   , the factory interface  102  includes a docking station  140  and factory interface robots  142  disposed within the docking station  140  to facilitate transfer of substrates. The docking station  140  is coupled to one or more front opening unified pods (FOUPs)  144 . In some examples, each factory interface robot  142  generally comprises a blade  148  disposed on one end of the respective factory interface robot  142  configured to transfer substrates from the factory interface  102  to the load lock chambers  104 ,  106 . 
     The load lock chambers  104 ,  106  have respective ports  150 ,  152  coupled to the factory interface  102  and respective ports  154 ,  156  coupled to the transfer chamber  116 . The transfer chamber  116  has respective ports  170 ,  172 ,  174 ,  176  coupled to processing chambers  124 ,  126 ,  128 ,  130 . The ports  154 ,  156 ,  170 ,  172 ,  174 ,  176  can be, for example, slit openings with slit valves for passing substrates therethrough by the transfer robot  118  and for providing a seal between respective chambers to prevent a gas from passing between the respective chambers. Generally, any port is open for transferring a substrate therethrough; otherwise, the port is closed. The transfer robot  118  may be a dual-handler robot, such that the transfer robot  118  is configured to handle two substrates simultaneously. 
     The load lock chambers  104 ,  106 , the transfer chamber  116 , and the processing chambers  124 ,  126 ,  128 ,  130  may be fluidly coupled to a gas and pressure control system. The gas and pressure control system can include one or more gas pumps (e.g., turbo pumps, cryo-pumps, roughing pumps, etc.), gas sources, various valves, and conduits fluidly coupled to the various chambers. In operation, a factory interface robot  142  transfers a substrate from a FOUP  144  through a port  150  or  152  to a load lock chamber  104  or  106 . The gas and pressure control system then pumps down the load lock chamber  104  or  106 . The gas and pressure control system further maintains the transfer chamber  116  with an interior low pressure or vacuum environment (which may include an inert gas). Hence, the pumping down of the load lock chamber  104  or  106  facilitates passing the substrate between e.g., the atmospheric environment of the factory interface  102  and the low pressure or vacuum environment of the transfer chamber  116 . 
     One or both of the load lock chambers  104 ,  106  are configured to cool a substrate. The load lock chambers  104 ,  106  may therefore be referred to as cool-down chambers or cooling chambers. The load lock chambers  104 ,  106  are configured to have a substrate pass therethrough. In examples described herein, a substrate may be inserted into the load lock chamber  104  after being processed within one of the processing chambers  124 ,  126 ,  128 ,  130 . The substrate is cooled within the load lock chamber  104  before being moved into the docking station  140 . 
     The processing chambers  124 ,  126 ,  128 ,  130  can be any appropriate chamber for processing a substrate. In some examples, additional transfer chambers and processing chambers are included within the processing system, such that at least one processing chamber is capable of performing a cleaning process and another processing chamber can be capable of performing an etch process. Each of the processing chambers  124 ,  126 ,  128 ,  130  can be capable of performing a deposition process, such as an epitaxial growth processes. The cleaning chamber may be a SiCoNi™ Preclean chamber available from Applied Materials of Santa Clara, Calif. The etching chamber may be a Selectra™ Etch chamber available from Applied Materials of Santa Clara, Calif. Other chambers, including those from other manufacturers, are also contemplated. In some embodiments, one of the processing chambers  124 ,  126 ,  128 ,  130  is a cooling chamber or cool-down chamber separate from the load lock chambers  104 ,  106 . 
     A system controller  190  is coupled to the processing system  100  for controlling the processing system  100  or components thereof. For example, the system controller  190  may control the operation of the processing system  100  using a direct control of the chambers  104 ,  106 ,  116 ,  124 ,  126 ,  128 ,  130  of the processing system  100  or by controlling controllers associated with the chambers  104 ,  106 ,  116 ,  124 ,  126 ,  128 ,  130 . In operation, the system controller  190  enables data collection and feedback from the respective chambers to coordinate performance of the processing system  100 . 
     The system controller  190  generally includes a central processing unit (CPU)  192 , memory  194 , and support circuits  196 . The CPU  192  may be one of any form of a general purpose processor that can be used in an industrial setting. The memory  194 , or non-transitory computer-readable medium, is accessible by the CPU  192  and may be one or more of memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The support circuits  196  are coupled to the CPU  192  and may comprise cache, clock circuits, input/output subsystems, power supplies, and the like. The various methods disclosed herein may generally be implemented under the control of the CPU  192  by the CPU  192  executing computer instruction code stored in the memory  194  (or in memory of a particular processing chamber) as, e.g., a software routine. When the computer instruction code is executed by the CPU  192 , the CPU  192  controls the chambers to perform processes in accordance with the various methods. Other processing systems can be in other configurations. For example, more or fewer processing chambers may be coupled to a transfer apparatus. 
       FIG.  2    is a schematic cross-sectional view of a process chamber  200  that may be used to perform deposition processes. The process chamber  200  may be used as any one of the processing chambers  124 ,  126 ,  128 ,  130 . The process chamber  200  is utilized to grow an epitaxial film on a substrate, such as the substrate  202 . The process chamber  200  creates a cross-flow of precursors across the top surface  250  of the substrate  202 . 
     The process chamber  200  includes an upper body  256 , a lower body  248  disposed below the upper body  256 , a flow module  212  disposed between the upper body  256  and the lower body  248 . The upper body  256 , the flow module  212 , and the lower body  248  form a chamber body. Disposed within the chamber body is a substrate support  206 , an upper dome  208 , a lower dome  210 , a plurality of upper lamps  241 , and a plurality of lower lamps  243 . As shown, the controller  190  is in communication with the process chamber  200  and is used to control processes, such as those described herein. The substrate support  206  is disposed between the upper dome  208  and the lower dome  210 . The plurality of upper lamps  241  are disposed between the upper dome  208  and a lid  254 . The lid  254  includes a plurality of sensors  253  disposed therein for measuring the temperature within the process chamber  200 . The plurality of lower lamps  243  are disposed between the lower dome  210  and a floor  252 . The plurality of lower lamps  243  form a lower lamp assembly  245 . 
     A processing volume  236  is formed between the upper dome  208  and the lower dome  210 . The processing volume  236  has the substrate support  206  disposed therein. The substrate support  206  includes a top surface on which the substrate  202  is disposed. The substrate support  206  is attached to a shaft  218 . The shaft  218  is connected to a motion assembly  221 . The motion assembly  221  includes one or more actuators and/or adjustment devices that provide movement and/or adjustment of the shaft  218  and/or the substrate support  206  within the processing volume  236 . The motion assembly  221  includes a rotary actuator  222  that rotates the shaft  218  and/or the substrate support  206  about a longitudinal axis A of the process chamber  200 . The motion assembly  221  further includes a vertical actuator  224  to lift and lower the substrate support  206  in the z-direction. The motion assembly includes a tilt adjustment device  226  that is used to adjust the planar orientation of the substrate support  206  and a lateral adjustment device  228  that is used to adjust the position of the shaft  218  and the substrate support  206  side to side within the processing volume  236 . 
     The substrate support  206  may include lift pin holes  207  disposed therein. The lift pin holes  207  are sized to accommodate a lift pin  232  for lifting of the substrate  202  from the substrate support  206  either before or after a deposition process is performed. The lift pins  232  may rest on lift pin stops  234  when the substrate support  206  is lowered from a processing position to a transfer position. 
     The flow module  212  includes a plurality of process gas inlets  214 , a plurality of purge gas inlets  264 , and one or more exhaust gas outlets  216 . The plurality of process gas inlets  214  and the plurality of purge gas inlets  264  are disposed on the opposite side of the flow module  212  from the one or more exhaust gas outlets  216 . One or more flow guides  246  are disposed below the plurality of process gas inlets  214  and the one or more exhaust gas outlets  216 . The flow guide  246  is disposed above the purge gas inlets  264 . A liner  263  is disposed on the inner surface of the flow module  212  and protects the flow module  212  from reactive gases used during deposition processes. The process gas inlets  214  and the purge gas inlets  264  are positioned to flow a gas parallel to the top surface  250  of a substrate  202  disposed within the processing volume  236 . The process gas inlets  214  are fluidly connected to a process gas source  251 . The purge gas inlets  264  are fluidly connected to a purge gas source  262 . The one or more exhaust gas outlets  216  are fluidly connected to an exhaust pump  257 . Each of the process gas source  251  and the purge gas source  262  may be configured to supply one or more precursors or process gases into the processing volume  236 . 
       FIG.  3    is a schematic cross-sectional view of a cool-down chamber  300 . The cool-down chamber  300  may be utilized as either or both of the load lock chambers  104 ,  106 . In some embodiments, the cool-down chamber  300  may be one of the processing chambers  124 ,  126 ,  128 ,  130 . The cool-down chamber  300  is configured to cool a substrate, such as the substrate  202 . The substrate  202  is positioned on a cooling pedestal  304 . The cooling pedestal  304  is configured to cool the substrate  202 . The cooling pedestal  304  is disposed within a chamber body  302 . The chamber body  302  forms a process volume  320 . The process volume  320  is maintained at a vacuum. 
     The cooling pedestal  304  is disposed within the process volume  320 . The cooling pedestal  304  includes a support plate  306 . The support plate  306  is a ring-shaped plate and is configured to support an outer edge of the substrate  202 . The outer edge of the substrate  202  rests on a support ledge  308  of the support plate  306 . The central portion of the support plate  306  is open. A plenum  314  is disposed within the opening and between a bottom surface  318  of the substrate  202  and a top surface  316  of the cooling pedestal  304 . The substrate  202  is not disposed directly on the top surface  316  of the cooling pedestal  304  to avoid rapid cooling of the bottom surface  318  of the substrate  202  relative to the top surface  250 . The separation of the substrate  202  from the cooling pedestal  304  further reduces contamination of the substrate  202  from the material of the cooling pedestal  304 . The cooling pedestal  304  is formed of a thermally conductive material, such as a metal or a metal alloy. 
     One or more cooling elements  310  are disposed through the cooling pedestal  304 . The cooling elements  310  assist in regulating the temperature of the cooling pedestal  304 . In some embodiments, the cooling elements  310  include one or more cooling channels. The one or more cooling channels may include a cooled liquid flowing therethrough, such as chilled water. The cooling liquid is provided from a coolant source  312 . The process volume  320  is also maintained at a relatively cool temperature. The temperatures of one or both of the cooling pedestal  304  and the process volume  320  are below about 200° C., such as below about 100° C., such as below about 75° C. 
       FIGS.  4 A- 4 B  are schematic views of the transfer robot  118 . As shown in  FIG.  4 A , the transfer robot  118  is disposed within the transfer chamber  116 . The transfer robot  118  includes a first arm  408  and a second arm  410 . The first arm  408  includes a first handler  412 . The second arm  410  includes a second handler  414 . Each of the first handler  412  and the second handler  414  are configured to hold a substrate, such as the substrate  202 . 
     The first arm  408  and the second arm  410  are attached to a robot actuation shaft  406 . The robot actuation shaft  406  is centered about an axis C. The axis C is the axis about which the first arm  408  and the second arm  410  are moved. The robot actuation shaft  406  is coupled to an actuator  404  either mechanically or magnetically. In some embodiments, the coupling of the first arm  408 , second arm  410 , and the robot actuation shaft  406  to the actuator  404  is through magnets, such that the actuator  404  is disposed outside of the vacuum environment of the transfer chamber  116  and leak tightness is improved. The actuator  404  is configures to rotated the robot actuation shaft  406  and move the first arm  408  and the second arm  410 . 
     The actuator  404  is disposed on top of and mechanically coupled to a robot support shaft  402 . The robot support shaft  402  is configured to support the transfer robot  118 . 
     As shown in  FIG.  4 B , each of the first arm  408  and the second arm  410  are disposed opposite one another, such that the first arm  408  and the second arm  410  are disposed on opposite sides of the robot actuation shaft  406 . Each of the first arm  408  and the second arm  410  may be either independently operated or dependently operated. Independent operation includes moving one of the first arm  408  or the second arm  410  without the other of the first arm  408  or the second arm  410  being moved simultaneously. Dependent operation includes both of the first arm  408  and the second arm  410  moving simultaneously, such that both the first arm  408  and the second arm  410  are actuated the same amount at the same time around the axis C. 
     Each of the first arm  408  and the second arm  410  include a substrate support surface  420 , a substrate stop  418 , and two or more gripping arms  416 . The two or more gripping arms  416  are configured to contact wither side of a substrate and hold the substrate in place on the substrate support surface  420 . The substrate stop  418  is disposed at the distal end of the first arm  408  and the second arm  410  furthest from the robot actuation shaft  406 . The substrate stop  418  is a lip or ledge extending upward from the substrate support surface  420  and configured to support an outward portion of a substrate disposed on the substrate support surface  420 . The substrate stop  418  prevents the substrate from falling off of the substrate support surface  420  while the first arm  408  and the second arm  410  rotate around the axis C. 
       FIG.  5    illustrates a method  500  of cooling a substrate, such as the substrate  202 . The method  500  is performed after a first substrate has been processed within a process chamber, such as the processing chambers  124 ,  126 ,  128 ,  130  of  FIG.  1   . The processing chambers  124 ,  126 ,  128 ,  130  may be deposition chambers, such as the process chamber  200  of  FIG.  2   . Once the first substrate has been processed in one or more of the processing chambers the first substrate is removed from the processing chamber by a transfer robot, such as the transfer robot  118 , and held in a transfer chamber, such as the transfer chamber  116 , during an operation  502 . The first substrate is removed from the processing chamber by a first arm of the transfer robot. The first substrate may sometimes be referred to as a hot substrate as the first substrate is at a temperature of greater than about 250° C., such as greater than about 300° C., such as greater than about 350° C., such as greater than about 400° C., such as greater than about 450° C. when first removed from one of the processing chambers after a deposition operation. 
     While the first substrate is being removed from the processing chamber, a second substrate is disposed on the second arm of the transfer robot, such that the second substrate is held by the transfer robot simultaneously with the first substrate. The second substrate is previously located in any of the other processing chambers or may have been in another load lock chamber, such as one of the load lock chambers  104 ,  106 . 
     Throughout the method  500 , the transfer chamber  116  is held at vacuum and is constantly purged using a purge gas. The purge gas may be an inert gas. The purge gas may be one or a combination of helium (He), neon (Ne), argon (Ar), krypton (Kr), or nitrogen (N 2 ) gas. The transfer chamber  116  is held at a temperature of less than about 50° C., such as less than about 45° C., such as less than about 40° C. In some embodiments the temperature is about 20° C. to about 50° C., such as about 25° C. to about 45° C. 
     Once the first substrate has been removed from the processing chamber and is positioned within the transfer chamber on the first arm, the second substrate is inserted into the processing chamber using the second arm of the transfer robot. Positioning the second substrate in the processing chamber is performed during an operation  504 . While inserting the second substrate into the processing chamber during operation  504 , the first substrate is held on the first arm of the transfer robot. While the first substrate is held on the first arm within the transfer chamber, the first substrate is passively cooled. Passive cooling of the first substrate is caused by heat loss within the cool inner volume of the transfer chamber  116 . 
     After the second substrate has been inserted into the processing chamber, the first substrate remains on the first arm of the transfer robot until a cool-down chamber is available. Once a cool-down chamber is available, the first substrate is inserted into the cool-down chamber during another operation  506 . Inserting the first substrate into the cool-down chamber includes using the first arm to move the substrate and place the first substrate onto a substrate support within the cool-down chamber. The cool-down chamber may be one of the load lock chambers  104 ,  106 . The cool-down chamber is configured to have a similar architecture to the cool-down chamber  300  of  FIG.  3   . 
     Either after or simultaneously to the placement of the first substrate into the cool-down chamber, a cool down factor of the first substrate is determined during an operation  508 . The cool down factor is an offset value for the total cool down time of the first substrate. To determine the cool down factor, a time the first substrate is held on the first arm of the transfer robot and within the transfer chamber is recorded by the controller  190 . The time the first substrate is held on the first arm includes all of the time during operation  502 , operation  504 , and operation  506  in which the first substrate is disposed on the first arm. The amount of time the first substrate is held on the first arm within the transfer chamber is multiplied by a cooling variable. The cooling variable may also be described as a safety factor. The cooling variable is a multiplier for the total idle time of the substrate within the transfer chamber. The multiple of the cooling variable and the idle time is the cool down factor. The cool down factor is a unit of time. The cool down factor is determined during another operation  508  either after the first substrate is moved into the cool-down chamber or simultaneously with moving the first substrate into the cool-down chamber. The cool down factor is utilized to represent an amount of time which may be subtracted from the time the first substrate spends in the cool-down chamber. The cooling variable may be a factor of less than or equal to 1, such as about 0.5 to about 1.0, such as about 0.6 to about 0.9, such as about 0.6 to about 0.7, such as about 0.7. The cooling variable is generally less than  1  as the rate of cooling of the first substrate within the transfer chamber is less than the rate of cooling of the first substrate within the cool-down chamber. 
     After determining the cool down factor during the operation  508 , the cooling process of the first substrate is adjusted during an operation  510 . Adjusting the cooling process during the operation  510  includes changing at least one cooling parameter, such as the time the first substrate is to be cooled within the cool-down chamber. The first substrate is originally configured to be cooled for a first amount of time before the cool down factor is taken into consideration. The first amount of time is pre-determined and similar for each substrate run through the cool-down chamber. Accounting for the cool down factor enables each substrate to be cooled for an adjusted cooling time during the adjusted cooling process. The adjusted cooling time for each substrate is independent and may vary between the individual substrates as each individual substrate is run through the cool-down chamber. Adjusting the cooling process includes subtracting the cool down factor from the original cool down time. In this embodiment, the adjusted cool down time is the original cool down time minus the cool down factor. The cool down factor is the wait time on the transfer robot within the transfer chamber multiplied by the cooling variable. 
     Once the original cooling time has been adjusted during the operation  510 , the first substrate is cooled in the cool-down chamber during an operation  512 . The cooling of the first substrate during the operation  512  is performed for the adjusted cool down time. The adjusted cool down time is less than or equal to the original cool down time. The first substrate is cooled to a reduced temperature during the operation  512 . The reduced temperature is less than about 50° C., such as less than about 45° C., such as less than about 40° C. In some embodiments the reduced temperature is about 20° C. to about 50° C., such as about 25° C. to about 45° C. The temperature of the first substrate is reduced before being moved to another process chamber or out into a docking station, such as the docking station  140 . 
       FIG.  6    illustrates an exemplary graph  600  of substrate cool-down times as related to wait times within the transfer chamber. The graph  600  includes an independent axis  602 , which illustrates the substrate number of each substrate passing through a cool-down chamber and completing the method  500 . As shown, data from cooling a set of ten substrates are considered. Each of the ten substrates are run in the order illustrated and immediately after each other. The dependent axis  604  illustrates time in minutes. The time illustrated includes two data sets. A first data set is the wait time the substrate spends on a handler or first arm of a transfer robot and within the transfer chamber. A second data set is the cool down time of the substrate within the cool-down chamber once the time the first substrate spends within the transfer chamber is accounted for using the method  500 . 
     The graph  600  utilizes a cooling variable of 0.7. The cooling variable is multiplied by the total wait time and subtracted from an original cool down time of 2 minutes. The original cool down time may be varied depending upon the beginning temperature of the substrate, the desired end temperature of the substrate, the desired temperature change across the substrate per unit time, and the conditions within the cool-down chamber. As illustrated in the graph  600 , a first substrate has a wait time of about 0.5 minutes. The 0.5 minutes is multiplied by the cooling variable of 0.7 and subtracted from the original cool down time of 2 minutes to obtain an adjusted cool down time of 1.65 minutes. A second substrate and a third substrate have a similar wait time and adjusted cool down time as the first substrate. A third substrate has a wait time of about 0 minutes and therefore maintains the total original cool down time of 2 minutes. A fifth substrate has a wait time of 2 minutes. The 2 minutes is multiplied by the cooling variable of 0.7 and subtracted from the original cool down time of 2 minutes to obtain an adjusted cool down time of 0.6 minutes. The sixth substrate, the seventh substrate, the eighth substrate, the ninth substrate, and the tenth substrate also show reduced cool down times using methods described herein. 
     By reducing the amount of cool down time for some of the substrates, the rate at which substrates are transferred into and out of the cool-down chamber is increased on average. As the cool-down time of the substrates had been found to be a limiting factor, the increased substrate transfer rate through the cool-down chamber increases the overall throughput of substrates through the overall processing system  100 . 
     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.