Patent Publication Number: US-2023142890-A1

Title: Method of Manufacturing Semiconductor Device, Cleaning Method, and Non-transitory Computer-readable Recording Medium

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This non-provisional U.S. patent application is a continuation of U.S. patent application Ser. No. 17/669,339, filed Feb. 10, 2022. This non-provisional U.S. patent application claims priority under 35 U.S.C. § 119(a)-(d) of Japanese Patent Application No. 2021-142399, filed on Sep. 1, 2021, in the Japanese Patent Office, the entire contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a method of manufacturing a semiconductor device. 
     BACKGROUND 
     According to some related arts, as a part of a manufacturing process of a semiconductor device, a process gas is supplied to a substrate in a process vessel to process a film on the substrate (that is, to perform a film process). 
     When the film process is performed using a substrate processing apparatus according to some related arts, deposits may adhere to an inside of the process vessel of the substrate processing apparatus. Therefore, after the film process, a cleaning process may be performed in which a cleaning gas is supplied into the process vessel to remove the deposits adhering to the inside of the process vessel. 
     However, when the cleaning process is performed at a high temperature after the film process is performed at a high temperature, defects may occur in some locations. Therefore, it is preferable to lower an inner temperature of the process vessel to a desired temperature before performing the cleaning process after the film process. However, in such a case, a downtime of the substrate processing apparatus may increase and an operating rate of the substrate processing apparatus may be affected. 
     SUMMARY 
     According to the present disclosure, there is provided a technique capable of shortening a downtime of a substrate processing apparatus and improving an operating rate of the substrate processing apparatus. 
     According to one or more embodiments of the present disclosure, there is provided a technique related to a method of manufacturing a semiconductor device, including: (a) heating a substrate to a first temperature while supplying a process gas into a process vessel accommodating a substrate support; (b) lowering a temperature of a low temperature structure provided in the process vessel to a second temperature lower than the first temperature by supplying a coolant to a coolant flow path provided in the process vessel for a predetermined time after (a), wherein a defect occurs when a cleaning gas is supplied to the low temperature structure at the first temperature; and (c) cleaning the low temperature structure by supplying the cleaning gas into the process vessel after (b), wherein the low temperature structure comprises at least one selected from the group consisting of: a material provided with a coating capable of preventing corrosion due to the process gas is applied; a structure located in vicinity of a viewport where through an inside of the process vessel is visually recognizable from an outside of the process vessel; and a seal provided around the coolant flow path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram schematically illustrating an exemplary configuration of a substrate processing apparatus according to one or more embodiments of the present disclosure. 
         FIG.  2    is a diagram schematically illustrating an exemplary configuration of a process vessel of the substrate processing apparatus according to the embodiments of the present disclosure. 
         FIG.  3    is a block diagram schematically illustrating a configuration of a controller and related components of the substrate processing apparatus according to the embodiments of the present disclosure. 
         FIG.  4    is a flowchart schematically illustrating a substrate processing according to the embodiments of the present disclosure. 
         FIG.  5    is a flowchart schematically illustrating a film-forming step of the substrate processing according to the embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments 
     Hereinafter, one or more embodiments (also simply referred to as “embodiments”) according to the technique of the present disclosure will be described with reference to the drawings. Like reference numerals represent like components in the drawings, and redundant descriptions related thereto will be omitted. In the drawings, for the sake of convenience of the descriptions, features such as width, thickness and shape of each component may be schematically illustrated as compared with actual structures. However, the drawings are merely examples of the embodiments, and the embodiments according to the technique of the present disclosure are not limited thereto. 
     (1) Configuration of Substrate Processing Apparatus 
       FIG.  1    is a diagram schematically illustrating a cross-section of a single wafer type substrate processing apparatus (hereinafter, also simply referred to as a “substrate processing apparatus”)  10  of performing a method of manufacturing a semiconductor device when viewed from above. A transfer device of the substrate processing apparatus  10  of a cluster type according to the present embodiments is divided into a vacuum side and an atmospheric side. In addition, in the substrate processing apparatus  10 , a FOUP (Front Opening Unified Pod, hereinafter, also referred to as a “pod”)  100  is used as a carrier for transferring a wafer  200  serving as a substrate. 
     &lt;Configuration of Vacuum Side&gt; 
     As shown in  FIG.  1   , the substrate processing apparatus  10  includes a first transfer chamber  103  capable of withstanding a pressure (negative pressure) below the atmospheric pressure such as a pressure in a vacuum state. For example, a housing  101  of the first transfer chamber  103  is pentagonal when viewed from above. The housing  101  is of a box shape with closed upper and lower ends. 
     In the first transfer chamber  103 , a first substrate transfer device  112  configured to transfer the wafer  200  is installed. 
     Auxiliary chambers (which are load lock chambers)  122  and  123  are connected to a side wall among five sidewalls of the housing  101  that is located on a front side (lower side in  FIG.  1   ) of the housing  101  via gate valves  126  and  127 , respectively. The auxiliary chambers  122  and  123  are capable of withstanding the negative pressure. The wafer  200  can be transferred (loaded) into or transferred (unloaded) out of the auxiliary chambers  122  and  123 . 
     A process vessel  202   a  serving as a part of a process module PM 1 , a process vessel  202   b  serving as a part of a process module PM 2 , a process vessel  202   c  serving as a part of a process module PM 3  and a process vessel  202   d  serving as a part of a process module PM 4 , which are configured to perform a desired (predetermined) processing on the wafer  200 , are connected adjacently to the four sidewalls (among the five sidewalls) of the housing  101  that are located on a rear side (back side) (upper side in  FIG.  1   ) of the housing  101  of the first transfer chamber  103  with a gate valve  70   a , a gate valve  70   b , a gate valve  70   c  and a gate valve  70   d  interposed therebetween, respectively. 
     &lt;Configuration of Atmospheric Side&gt; 
     A second transfer chamber  121  wherein the wafer  200  can be transferred under the atmospheric pressure is connected to front sides of the auxiliary chambers  122  and  123  via a gate valve  128  and a gate valve  129 . In the second transfer chamber  121 , a second substrate transfer device  124  configured to transfer the wafer  200  is installed. 
     A notch aligner  106  is installed on a left side of the second transfer chamber  121 . The notch aligner  106  may be an orientation flat aligner. 
     A substrate loading/unloading port  134  and a pod opener  108  are installed at a front side of a housing  125  of the second transfer chamber  121  to load the wafer  200  into or unload the wafer  200  out of the second transfer chamber  121 . A loading port structure (which is an I/O stage)  105  is installed opposite to the pod opener  108  with the substrate loading/unloading port  134  interposed therebetween. That is, the loading port structure  105  is installed outside the housing  125 . The pod opener  108  is configured to open and close a cap  100   a  of the pod  100 . The pod opener  108  includes a closure (not shown) capable of opening and closing the substrate loading/unloading port  134 . When the cap  100   a  of the pod  100  placed on the loading port structure  105  is opened or closed, the wafer  200  may be loaded into the pod  100  or unloaded out of the pod  100 . In addition, the pod  100  is loaded onto or unloaded out of the loading port structure  105  by an in-step transfer device (not shown) such as an OHT (Overhead Hoist Transfer). 
     (2) Configuration of Process Module 
     Subsequently, configurations of the process vessels  202   a  through  202   d  of the process modules PM 1  through PM 4  will be described. 
     Each of the process modules PM 1  through PM 4  functions as a part of the single wafer type substrate processing apparatus. The process modules PM 1  through PM 4  are provided with the process vessels  202   a  through  202   d , respectively. Since the configurations of the process vessels  202   a  through  202   d  are substantially the same for the process modules PM 1  through PM 4 , a process vessel  202  among the process vessels  202   a  through  202   d  will be described in detail below. That is, the process vessels  202   a  through  202   d  may be individually referred to as the process vessel  202 . 
       FIG.  2    is a diagram schematically illustrating an exemplary configuration of the process vessel  202  of the substrate processing apparatus  10 . 
     &lt;Process Vessel&gt; 
     For example, the process vessel  202  is constituted by a flat and sealed vessel whose horizontal cross-section is circular. The process vessel  202  is constituted by an upper vessel  2021  made of a non-metallic material such as quartz and ceramics and a lower vessel  2022  made of a metal material such as aluminum (Al) and stainless steel (SUS). A process space (also referred to as a “process chamber”)  201  in which the wafer  200  is processed is provided in an upper region (that is, a space above a substrate mounting table  212  described later) of the process vessel  202 , and a transfer space  203  is provided below the process space  201  in a space surrounded by the lower vessel  2022 . 
     Lift pins  207  are provided at a bottom of the lower vessel  2022 . 
     A substrate loading/unloading port  206  is provided on a side surface (side wall) of the lower vessel  2022  (which is a part of the process vessel  202 ) adjacent to a gate valve  205  (which corresponds to one of the gate valves  70   a  through  70   d  described above). The wafer  200  can be transferred into or out of the transfer space  203  through the substrate loading/unloading port  206 . An O-ring  209   a  serving as a seal is provided around the gate valve  205 . The gate valve  205  is constituted by a valve body  205   a  capable of opening and closing the substrate loading/unloading port  206  and a shaft  205   b  capable of supporting the valve body  205   a . In other words, the gate valve  205  constituted by the valve body  205   a  and the shaft  205   b  is provided adjacent to the substrate loading/unloading port  206 . By elevating or lowering the shaft  205   b  and the valve body  205   a , it is possible to open or close the substrate loading/unloading port  206 . 
     In addition, a viewport  300  is provided on a side surface (side wall) of the upper vessel  2021  (which is a part of the process vessel  202 ). The viewport  300  is configured such that the process space  201  (which is an inner space of the process vessel  202 ) can be visually recognized from an outside of the process vessel  202  through the viewport  300 . An O-ring  209   b  serving as a seal is provided around the viewport  300 . Alternatively, as long as the process space  201  can be visually recognized through the viewport  300 , the viewport  300  may be provided on another wall such as an upper wall of the upper vessel  2021 . 
     &lt;Substrate Support&gt; 
     A substrate support (also referred to as a “susceptor”)  210  configured to support the wafer  200  is provided in the process space  201 . The substrate support  210  is constituted mainly by: the substrate mounting table  212  provided with a substrate placing surface  211  on which the wafer  200  is placed; and a heater  213  serving as a heating structure embedded in the substrate mounting table  212 . Through-holes  214  through which the lift pins  207  penetrate are provided at positions of the substrate mounting table  212  corresponding to the lift pins  207 . 
     The substrate mounting table  212  is supported by a shaft  217 . The shaft  217  penetrates the bottom of the lower vessel  2022 , and is connected to an elevator  218  at the outside of the process vessel  202 . 
     The wafer  200  placed on the substrate placing surface  211  of the substrate mounting table  212  can be elevated or lowered by operating the elevator  218  to elevate or lower the shaft  217  and the substrate mounting table  212 . In addition, a bellows  219  covers a periphery of a lower end portion of the shaft  217  to maintain the process space  201  airtight. 
     When the wafer  200  is transferred, the substrate mounting table  212  is lowered until the substrate placing surface  211  faces the substrate loading/unloading port  206  (that is, until a wafer transfer position is reached). When the wafer  200  is processed, the wafer  200  is elevated until the wafer  200  reaches a processing position (also referred to as a “wafer processing position”) in the process space  201 . 
     Specifically, when the substrate mounting table  212  is lowered to the wafer transfer position, upper ends of the lift pins  207  protrude from an upper surface of the substrate placing surface  211 , and the lift pins  207  support the wafer  200  from thereunder. In addition, when the substrate mounting table  212  is elevated to the wafer processing position, the lift pins  207  are buried from the upper surface of the substrate placing surface  211  and the substrate placing surface  211  supports the wafer  200  from thereunder. 
     &lt;Shower Head&gt; 
     A shower head  230  serving as a gas dispersion structure is provided at an upper portion of the process space  201  (that is, provided at an upstream side of the process space  201  in a gas supply direction). For example, the shower head  230  is inserted into a hole  2021   a  provided in the upper vessel  2021 . 
     A lid  231  of the shower head  230  is made of, for example, an electrically conductive and thermally conductive metal. A block  233  is provided between the lid  231  and the upper vessel  2021 . The block  233  electrically and thermally insulates the lid  231  from the upper vessel  2021 . Further, an O-ring  209   c  serving as a seal is provided between the lid  231  and the block  233 . 
     In addition, a through-hole  231   a  into which a gas supply pipe  241  serving as a first dispersion structure is inserted is provided in the lid  231  of the shower head  230 . The gas supply pipe  241  inserted in the through-hole  231   a  is configured to disperse a gas supplied into a shower head buffer chamber  232  (which is a space provided in the shower head  230 ). For example, the gas supply pipe  241  is constituted by a front end structure  241   a  inserted into the shower head  230  and a flange  241   b  fixed to the lid  231 . For example, the front end structure  241   a  is of a cylindrical shape, and a dispersion hole (or dispersion holes: not shown) is provided on a side surface of the front end structure  241   a . Then, a gas supplied through a gas supplier (which is a gas supply system or a gas supply structure) described later is supplied into the shower head buffer chamber  232  through the dispersion hole provided in the front end structure  241   a.    
     In addition, the shower head  230  is provided with a dispersion plate  234  serving as a second dispersion structure configured to disperse the gas supplied through the gas supplier (gas supply system) described later. An upstream side of the dispersion plate  234  is referred to as the shower head buffer chamber  232 , and a downstream side of the dispersion plate  234  is referred to as the process space  201 . The dispersion plate  234  is provided with a plurality of through-holes  234   a . The dispersion plate  234  is arranged above the substrate placing surface  211  so as to face the substrate placing surface  211 . Therefore, the shower head buffer chamber  232  communicates with the process space  201  via the plurality of through-holes  234   a  provided in the dispersion plate  234 . Further, an O-ring  209   d  serving as a seal is provided between the lid  231  and the dispersion plate  234 . 
     The through-hole  231   a  into which the gas supply pipe  241  is inserted is provided in the shower head buffer chamber  232 . 
     &lt;Gas Supplier&gt; 
     A common gas supply pipe  242  is connected to the gas supply pipe  241  inserted into the through-hole  231   a  provided in the lid  231  of the shower head  230 . The gas supply pipe  241  and the common gas supply pipe  242  communicate with each other through their inner structures. Further, a gas supplied through the common gas supply pipe  242  is supplied into the shower head  230  through the gas supply pipe  241  and the through-hole  231   a.    
     A first gas supply pipe  243   a , a second gas supply pipe  244   a  and a third gas supply pipe  245   a  are connected to the common gas supply pipe  242 . The second gas supply pipe  244   a  may be connected to the common gas supply pipe  242  via a remote plasma structure (also referred to as a “remote plasma unit” or simply referred to as an “RPU”)  244   e . Although the second gas supply pipe  244   a  is connected to the common gas supply pipe  242  via the remote plasma structure  244   e  as shown in  FIG.  2   , in case the remote plasma structure  244   e  is not provided, the second gas supply pipe  244   a  can be directly connected to the common gas supply pipe  242 . 
     A first element-containing gas is mainly supplied through a first gas supplier (which is a first gas supply system or a first gas supply structure)  243  including the first gas supply pipe  243   a , and a second element-containing gas is mainly supplied through a second gas supplier (which is a second gas supply system or a second gas supply structure)  244  including the second gas supply pipe  244   a . When processing the wafer  200 , an inert gas is mainly supplied through a third gas supplier (which is a third gas supply system or a third gas supply structure)  245  including the third gas supply pipe  245   a , and when cleaning a component such as an inner space of the shower head  230  and the process space  201 , a cleaning gas is mainly supplied through the third gas supplier  245 . 
     &lt;First Gas Supplier&gt; 
     A first gas supply source  243   b , a mass flow controller (MFC)  243   c  serving as a flow rate controller (flow rate control structure) and a valve  243   d  serving as an opening/closing valve are sequentially provided in this order at the first gas supply pipe  243   a  from an upstream side toward a downstream side of the first gas supply pipe  243   a . A gas containing a first element (hereinafter, also referred to as the “first element-containing gas”) is supplied into the shower head  230  from the first gas supply source  243   b  through the first gas supply pipe  243   a  provided with the MFC  243   c  and the valve  243   d  and the common gas supply pipe  242 . 
     The first element-containing gas serves as a source gas, which is one of process gases. According to the present embodiments, for example, the first element is silicon (Si). That is, for example, the first element-containing gas includes a silicon-containing gas. A source material of the first element-containing gas may be in a solid state, a liquid state or a gaseous state under the normal temperature and the normal pressure. When the source material of the first element-containing gas is in a liquid state under the normal temperature and the normal pressure, a vaporizer (not shown) may be provided between the first gas supply source  243   b  and the MFC  243   c . Hereinafter, the present embodiments will be described in detail by way of an example in which the source material of the first element-containing gas is in a gaseous state under the normal temperature and the normal pressure. 
     A downstream end of a first inert gas supply pipe  246   a  is connected to the first gas supply pipe  243   a  downstream of the valve  243   d  provided at the first gas supply pipe  243   a . An inert gas supply source  246   b , a mass flow controller (MFC)  246   c  serving as a flow rate controller (flow rate control structure) and a valve  246   d  serving as an opening/closing valve are sequentially provided in this order at the first inert gas supply pipe  246   a  from an upstream side toward a downstream side of the first inert gas supply pipe  246   a . The inert gas is supplied into the shower head  230  from the inert gas supply source  246   b  through the first inert gas supply pipe  246   a  provided with the MFC  246   c  and the valve  246   d , the first gas supply pipe  243   a  and the common gas supply pipe  242 . 
     According to the present embodiments, the inert gas acts as a carrier gas of the first element-containing gas. It is preferable that a gas that does not react with the first element is used as the inert gas. Specifically, for example, nitrogen (N2) gas may be used as the inert gas. Alternatively, instead of the N2 gas, a rare gas such as helium (He) gas, neon (Ne) gas and argon (Ar) gas may be used as the inert gas. 
     The first gas supplier (also referred to as a “silicon-containing gas supplier”, a “silicon-containing gas supply system”, or a “silicon-containing gas supply structure”)  243  is constituted mainly by the first gas supply pipe  243   a , the MFC  243   c  and the valve  243   d . A first inert gas supplier (which is a first inert gas supply system or a first inert gas supply structure) is constituted mainly by the first inert gas supply pipe  246   a , the MFC  246   c  and the valve  246   d . The first gas supplier  243  may further include the first gas supply source  243   b  and the first inert gas supplier. In addition, the first inert gas supplier may further include the inert gas supply source  246   b  and the first gas supply pipe  243   a . Since the first gas supplier  243  is configured to supply the source gas which is one of the process gases, the first gas supplier  243  is a part of a process gas supplier (also referred to as a “process gas supply system” or a “process gas supply structure”). 
     &lt;Second Gas Supplier&gt; 
     The remote plasma structure  244   e  is provided downstream of the second gas supply pipe  244   a . A second gas supply source  244   b , a mass flow controller (MFC)  244   c  serving as a flow rate controller (flow rate control structure) and a valve  244   d  serving as an opening/closing valve are sequentially provided in this order at the second gas supply pipe  244   a  from an upstream side toward a downstream side of the second gas supply pipe  244   a . A gas containing a second element (hereinafter, also referred to as the “second element-containing gas”) is supplied into the shower head  230  from the second gas supply source  244   b  through the second gas supply pipe  244   a  provided with the MFC  244   c  and the valve  244   d , the remote plasma structure  244   e  and the common gas supply pipe  242 . 
     When the second element-containing gas is supplied onto the wafer  200  in a plasma state, the remote plasma structure  244   e  is operated to convert the second element-containing gas into the plasma state. 
     The second element-containing gas serves as a reactive gas or a modifying gas, which is one of process gases. According to the present embodiments, for example, the second element-containing gas contains the second element different from the first element described above. For example, the second element is one of oxygen (O), nitrogen (N) and carbon (C). According to the present embodiments, for example, a nitrogen-containing gas may be used as the second element-containing gas. Specifically, for example, ammonia (NH3) gas may be used as the nitrogen-containing gas. 
     A downstream end of a second inert gas supply pipe  247   a  is connected to the second gas supply pipe  244   a  downstream of the valve  244   d  provided at the second gas supply pipe  244   a . An inert gas supply source  247   b , a mass flow controller (MFC)  247   c  serving as a flow rate controller (flow rate control structure) and a valve  247   d  serving as an opening/closing valve are sequentially provided in this order at the second inert gas supply pipe  247   a  from an upstream side toward a downstream side of the second inert gas supply pipe  247   a . The inert gas is supplied into the shower head  230  from the inert gas supply source  247   b  through the second inert gas supply pipe  247   a  provided with the MFC  247   c  and the valve  247   d , the second gas supply pipe  244   a  and the common gas supply pipe  242 . 
     According to the present embodiments, the inert gas acts as a carrier gas of the second element-containing gas or a dilution gas of the second element-containing gas in a substrate processing described later. Specifically, for example, the N2 gas may be used as the inert gas. Alternatively, instead of the N2 gas, a rare gas such as helium (He) gas, neon (Ne) gas and argon (Ar) gas may be used as the inert gas. 
     The second gas supplier (also referred to as a “nitrogen-containing gas supplier”, a “nitrogen-containing gas supply system”, or a “nitrogen-containing gas supply structure”)  244  is constituted mainly by the second gas supply pipe  244   a , the MFC  244   c  and the valve  244   d . A second inert gas supplier (which is a second inert gas supply system or a second inert gas supply structure) is constituted mainly by the second inert gas supply pipe  247   a , the MFC  247   c  and the valve  247   d . The second gas supplier  244  may further include the second gas supply source  244   b , the remote plasma structure  244   e  and the second inert gas supplier. In addition, the second inert gas supplier may further include the inert gas supply source  247   b , the second gas supply pipe  244   a  and the remote plasma structure  244   e . Since the second gas supplier  244  is configured to supply the reactive gas or the modifying gas, which is one of the process gases, the second gas supplier  244  is a part of the process gas supplier (also referred to as the process gas supply system or the process gas supply structure). 
     &lt;Third Gas Supplier&gt; 
     A third gas supply source  245   b , a mass flow controller (MFC)  245   c  serving as a flow rate controller (flow rate control structure) and a valve  245   d  serving as an opening/closing valve are sequentially provided in this order at the third gas supply pipe  245   a  from an upstream side toward a downstream side of the third gas supply pipe  245   a . The cleaning gas is supplied into the shower head  230  from the third gas supply source  245   b  through the third gas supply pipe  245   a  provided with the MFC  245   c  and the valve  245   d  and the common gas supply pipe  242 . 
     A downstream end of a third inert gas supply pipe  248   a  is connected to the third gas supply pipe  245   a  downstream of the valve  245   d  provided at the third gas supply pipe  245   a . An inert gas supply source  248   b , a mass flow controller (MFC)  248   c  serving as a flow rate controller (flow rate control structure) and a valve  248   d  serving as an opening/closing valve are sequentially provided in this order at the third inert gas supply pipe  248   a  from an upstream side toward a downstream side of the third inert gas supply pipe  248   a . The inert gas is supplied into the shower head  230  from the inert gas supply source  248   b  through the third inert gas supply pipe  248   a  provided with the MFC  248   c  and the valve  248   d , the third gas supply pipe  245   a  and the common gas supply pipe  242 . 
     In a film-forming step described later, the inert gas is supplied into the shower head  230  from the inert gas supply source  248   b  through the third inert gas supply pipe  248   a  provided with the MFC  248   c  and the valve  248   d , the third gas supply pipe  245   a  and the common gas supply pipe  242 . The inert gas supplied into the shower head  230  in the film-forming step acts as a purge gas of purging a gas remaining in the process vessel  202  or in the shower head  230 . Specifically, for example, the N2 gas may be used as the inert gas. Alternatively, instead of the N2 gas, a rare gas such as helium (He) gas, neon (Ne) gas and argon (Ar) gas may be used as the inert gas. 
     In a cleaning step described later, the cleaning gas is supplied into the shower head  230  from the third gas supply source  245   b  through the third gas supply pipe  245   a  provided with the MFC  245   c  and the valve  245   d  and the common gas supply pipe  242 . The cleaning gas supplied into the shower head  230  in the cleaning step acts as a gas of cleaning deposits remaining in the process vessel  202  or in the shower head  230 . Specifically, for example, nitrogen trifluoride (NF3) gas or chlorine trifluoride (ClF3) gas may be used as the cleaning gas. 
     The third gas supplier (also referred to as a “cleaning gas supplier”, a “cleaning gas supply system”, or a “cleaning gas supply structure”)  245  is constituted mainly by the third gas supply pipe  245   a , the MFC  245   c  and the valve  245   d . The third gas supplier  245  may further include the third gas supply source  245   b . A third inert gas supplier (which is a third inert gas supply system or a third inert gas supply structure) is constituted mainly by the third inert gas supply pipe  248   a , the MFC  248   c  and the valve  248   d . The third inert gas supplier may further include the inert gas supply source  248   b  and the third gas supply pipe  245   a . The third gas supplier  245  may further include the third inert gas supplier. 
     &lt;Gas Exhauster&gt; 
     A gas exhauster (which is a gas exhaust system or a gas exhaust structure) through which an inner atmosphere of the process vessel  202  is exhausted includes an exhaust pipe  263  connected to the process vessel  202 . Specifically, the gas exhauster includes the exhaust pipe  263  connected to the process space  201 . 
     The exhaust pipe  263  is connected to the process space  201  at a side portion of the process space  201 . An APC (Automatic Pressure Controller)  276  serving as a pressure controller configured to adjust (control) an inner pressure of the process space  201  to a predetermined pressure is provided at the exhaust pipe  263 . The APC  276  includes a valve body (not shown) capable of adjusting an opening degree thereof. The APC  276  is configured to adjust a conductance of the exhaust pipe  263  in accordance with an instruction from a controller  500  described later. In addition, a valve  275  serving as an opening/closing valve is provided at the exhaust pipe  263  upstream of the APC  276 , and a valve  277  serving as an opening/closing valve is provided at the exhaust pipe  263  downstream of the APC  276 . 
     In addition, a vacuum pump  278  is provided at the exhaust pipe  263  downstream of the valve  277 . The vacuum pump  278  is configured to exhaust the inner atmosphere of the process space  201  through the exhaust pipe  263 . 
     (3) Configuration of Cooling Structure 
     Subsequently, a cooling structure provided in the process vessel  202  will be described in detail. 
     First, the reason for providing the cooling structure will be described. In the film-forming step of forming a film on the wafer  200 , it is preferable to maintain the wafer  200  in a high temperature state. This is because, by maintaining the wafer  200  in the high temperature state, the energy of the gas supplied into the process space  201  and a reaction state on the wafer  200  may be higher than those in a low temperature (for example, room temperature) state. On the other hand, in the cleaning step, it is preferable that an inner temperature of the process vessel  202  is lower than that of the process vessel  202  in the film-forming step. 
     Specifically, as a measure against corrosion, for example, a coating such as a nickel fluoride coating may be formed on a component (such as the shaft  217  configured to support the shower head  230  and the substrate mounting table  212 ) made of a metal material such as stainless steel (SUS). In addition, as the measure against corrosion, for example, the coating such as the nickel fluoride coating may also be formed on a component such as the substrate loading/unloading port  206  and the gate valve  205 . When the cleaning gas such as the NF3 gas and the ClF3 gas is supplied to the component coated with the nickel fluoride coating in a high temperature state, the cleaning gas may react with the nickel fluoride coating and thus the nickel fluoride coating may be peeled off. Thereby, particles may be generated due to a reaction between the cleaning gas and the nickel fluoride coating, and thus the film may be contaminated. 
     In addition, when the shower head  230  also serves as an electrode for generating a plasma, if the coating is peeled off and becomes non-uniform, there occurs a difference in a plasma generation state between a portion with the coating and a portion without the coating, which leads to a non-uniform plasma generation. As a result, it may not be possible to form the film uniformly on the wafer  200 . In addition, an electric power may be concentrated on a portion with no coating where the coating is peeled off, and as a result, an abnormal discharge may occur. In addition, the process gases may corrode the metal material to thereby further generate the particles. Further, when the coating is non-uniform on a surface of the component parallel to the wafer  200 , an amount of the plasma may become non-uniform on a surface of the wafer  200 . Further, when the coating is non-uniform in the plurality of through-holes  234   a  of the shower head  230  along the vertical direction, the amount of plasma differs in each of the plurality of through-holes  234   a.    
     For the above reasons, after the film-forming step is performed in the high temperature state and before the cleaning step is performed, it is preferable that a location (or component) where defects occur when the cleaning gas is supplied in the high temperature state is cooled and maintain in the low temperature state. Hereinafter, the location where the defects occur when the cleaning gas is supplied in the high temperature state may also be referred to as a “low temperature structure”. 
     Therefore, as for such regions made of a material susceptible to corrosion by the process gases and being in contact with the process gases, a temperature lowering step is performed to cool the low temperature structure such as the shower head  230  and the shaft  217  where a corrosion prevention coating is performed. 
     Subsequently, a configuration of the cooling structure configured to cool the low temperature structure such as the shower head  230  and the shaft  217  will be described in detail with reference to  FIG.  2   . 
     A piping structure  316  is embedded around the lid  231  of the shower head  230  and in the vicinity of the O-rings  209   c  and  209   d . Specifically, the piping structure  316  is provided between a heater  416  described later and the O-ring  209   c  and between the heater  416  and the O-ring  209   d . In addition, a piping structure  317  is embedded around the substrate mounting table  212  and on an outer periphery of the heater  213 . Further, a piping structure  318  extending in an axial direction is embedded inside the shaft  217  configured to support the substrate mounting table  212 . 
     The piping structure  318  includes an outward path and a return path, each of which is connected to the piping structure  317 . A coolant supply pipe similar to a supply pipe  310  described later is connected to the outward path such that a coolant can be supplied to the outward path. Further, a coolant discharge pipe similar to a discharge pipe  311  described later is connected to the return path. The coolant supplied through the coolant supply pipe is supplied to the outward path of the piping structure  318  and the piping structure  317 , and is discharged through the coolant discharge pipe via the return path of the piping structure  318 . 
     Further, a piping structure  322  is embedded on the side surface (side wall) of the lower vessel  2022  above a periphery of the substrate loading/unloading port  206  between the O-ring  209   a  and a heater  422  described later. In addition, a piping structure  319  is embedded below the periphery of the substrate loading/unloading port  206  between the O-ring  209   a  and a heater  419  described later. That is, the piping structures  319  and  322  are arranged in a circumferential direction on the side surface (side wall) of the lower vessel  2022 , and the heaters  419  and  422  are arranged at inner peripheral regions of the piping structures  319  and  322 , respectively. Further, a piping structure  321  extending in the axial direction is embedded inside the shaft  205   b  configured to support the valve body  205   a  of the gate valve  205 . In addition, a piping structure  320  is embedded around the viewport  300  between the O-ring  209   b  and a heater  420  described later. 
     The coolant (cooling medium) is supplied to each of the piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322 . That is, each of the piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322  is used as a coolant flow path. Each of the piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322  is made of a metal piping material with a high thermal conductivity such as aluminum (Al). 
     In the present specification, the coolant is a medium capable of maintaining a property of cooling even at a first temperature described later. For example, the coolant may be a gaseous coolant such as an inert gas or air. Therefore, it is possible to immediately cool the housing after processing the wafer  200  at the first temperature. As a comparative example, for example, a liquid coolant (for example, Galden) may be used. However, when the liquid coolant is used, the liquid coolant may boil at the first temperature (for example, 800° C.) described later and a cooling effect may deteriorate. On the other hand, when the gaseous coolant such as the inert gas or the air is used, the cooling effect can be maintained even at the first temperature. Therefore, it is possible to cool the housing in the high temperature state, and as a result, it is possible to reduce the downtime. 
     The heater  416  serving as a heating structure is provided around the lid  231  and located radially more inward than the piping structure  316 . That is, the heater  416  is provided closer to a center of the process space  201  than the piping structure  316 . Further, the heater  213  is located radially more inward than the piping structure  317 . That is, the heater  213  is provided closer to the center of the process space  201  than the piping structure  317 . In addition, the heater  419  serving as a heating structure is provided below the periphery of the substrate loading/unloading port  206  and located radially more inward than the piping structure  319  (at an inner side of the process vessel  202 ). That is, the heater  419  is provided closer to the center of the process space  201  than the piping structure  319 . Further, the heater  422  serving as a heating structure is provided above the periphery of the substrate loading/unloading port  206  and located radially more inward than the piping structure  322  (at the inner side of the process vessel  202 ). That is, the heater  422  is provided closer to the center of the process space  201  than the piping structure  322 . In addition, the heater  420  serving as a heating structure is provided around the viewport  300  and located radially more inward than the piping structure  320  (at the inner side of the process vessel  202 ). That is, the heater  420  is provided closer to the center of the process space  201  than the piping structure  320 . 
     The piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322  are connected to one another via separate pipes. The supply pipe  310  through which the coolant is supplied is connected to an upstream end of the piping structure  319 , and the discharge pipe  311  through which the coolant is discharged is connected to a downstream end of the piping structure  322 . That is, the piping structures  316 ,  319 ,  320 ,  321  and  322  communicate with the supply pipe  310  and the discharge pipe  311 . That is, the supply pipe  310  through which the coolant is supplied is connected to an upstream end of the coolant flow path configured by connecting the piping structures  316 ,  319 ,  320 ,  321  and  322 , and the discharge pipe  311  through which the coolant is discharged to the outside of the process vessel  202  is connected to a downstream end of the coolant flow path. By combining the supply pipe and the discharge pipe as described above, it is possible to reduce the number of components for supplying and discharging the coolant, and it is also possible to reduce a cost of providing the components for supplying and discharging the coolant. Alternatively, the supply pipe  310  and the discharge pipe  311  may be connected to other piping structures, respectively. Further, the supply pipe  310  through which the coolant is supplied may be connected to an upstream end of a coolant flow path configured by connecting the piping structures  316  through  322 , and the discharge pipe  311  through which the coolant is discharged to the outside of the process vessel  202  may be connected to a downstream end of the coolant flow path configured by connecting the piping structures  316  through  322 . 
     A coolant gas supplier (which is a coolant gas supply system or a coolant gas supply structure)  310   a  and a valve  310   b  serving as an opening/closing valve are sequentially provided in this order at the supply pipe  310  from an upstream side toward a downstream side of the supply pipe  310 . The coolant gas supplier  310   a  is configured such that the coolant is supplied to the coolant flow path through the coolant gas supplier  310   a . That is, the supply pipe  310  is used as a supply pipe through which the coolant is supplied to the coolant flow path. Further, a valve  311   b  serving as an opening/closing valve is provided at the discharge pipe  311 , and a vacuum pump  311   c  is connected to the discharge pipe  311  at a downstream end of the discharge pipe  311 . That is, the vacuum pump  311   c  is connected to the coolant flow path. In addition, a pipe  312  serving as a branch path is connected to the discharge pipe  311  upstream of the valve  311   b . A valve  312   b  is provided at the pipe  312 . That is, the discharge pipe  311  is used as an exhaust pipe through which the coolant in the coolant flow path is discharged (or exhausted) to the outside of the process vessel  202 . 
     By cooling the low temperature structure such as the shower head  230  and the shaft  217  to a predetermined temperature or lower as described above, it is possible to reduce a thermal effect on the low temperature structure where the defects occur when being supplied with the cleaning gas at the first temperature (which is a film-forming temperature). 
     By supplying the coolant to the coolant flow path provided at locations such as a wall surface of the process vessel  202 , the shower head  230 , the substrate mounting table  212  and the shafts  217  and  205   b  in the temperature lowering step and vacuum-exhausting the coolant flow path in a temperature elevating step and by using the heaters  416 ,  419 ,  420  and  422  located radially more inward than the coolant flow path, it is possible to shorten a temperature lowering time and a temperature elevating time, and as a result, it is also possible to improve an operating rate of the substrate processing apparatus  10 . 
     Further, by arranging the coolant flow path in the vicinity of the O-rings  209   a  through  209   d  in a manner similar to that described above, it is possible to prevent (or suppress) the O-rings  209   a  through  209   d  from deteriorating. Therefore, the O-rings  209   a  through  209   d  may also be referred to as the low temperature structure. In addition, the wall surface of the process vessel  202  in the vicinity of the substrate loading/unloading port  206  or in the vicinity of the viewport  300  may also be referred to as the low temperature structure. 
     Further, temperature sensors  516 ,  517 ,  518 ,  519 ,  520  and  521  (which are configured to detect temperatures in the vicinity of the piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322 , respectively) are provided in the vicinity of the piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322 , respectively. 
     (4) Configuration of Controller 
     Subsequently, a configuration of the controller  500  serving as a control apparatus (control structure) will be described. 
     The controller  500  controls the above-described components of the substrate processing apparatus  10  to perform the substrate processing described later. 
     As shown in  FIG.  3   , the controller  500  is constituted by a computer including a CPU (Central Processing Unit)  500   a , a RAM (Random Access Memory)  500   b , a memory  500   c  and an I/O port  500   d . The RAM  500   b , the memory  500   c  and the I/O port  500   d  may exchange data with the CPU  500   a  through an internal bus  500   e . For example, an input/output device  501  such as a touch panel and a display device  472  such as a display are connected to the controller  500 . 
     The memory  500   c  is configured by a component such as a flash memory and a hard disk drive (HDD). For example, a control program configured to control the operation of the substrate processing apparatus  10  or a process recipe containing information on the sequences and conditions of the substrate processing described later may be readably stored in the memory  500   c . The process recipe is obtained by combining steps of the substrate processing described later such that the controller  500  can execute the steps to acquire a predetermined result, and functions as a program. Hereafter, the process recipe and the control program may be collectively or individually referred to as a “program”. In the present specification, the term “program” may refer to the process recipe alone, may refer to the control program alone, or may refer to both of the process recipe and the control program. The RAM  500   b  functions as a memory area (work area) where a program or data read by the CPU  500   a  is temporarily stored. 
     The I/O port  500   d  is connected to the above-described components such as the heaters  213 ,  416 ,  419 ,  420  and  422 , the MFCs  243   c ,  244   c ,  245   c ,  246   c ,  247   c  and  248   c , the valves  243   d ,  244   d ,  245   d ,  246   d ,  247   d ,  248   d ,  275 ,  277 ,  310   b ,  311   b  and  312   b , the APC  276 , the vacuum pumps  278  and  311   c , the gate valve  205 , the elevator  218 , the first substrate transfer device  112 , the second substrate transfer device  124  and the temperature sensors  516 ,  517 ,  518 ,  519 ,  520  and  521 . 
     The CPU  500   a  is configured to read the control program from the memory  500   c  and execute the read control program. In addition, the CPU  500   a  is configured to read the recipe from the memory  500   c  in accordance with an operation command inputted from the input/output device  501 . According to the contents of the read recipe, the CPU  500   a  may be configured to be capable of controlling various operations such as heating and cooling operations for the wafer  200  by the heater  213 , a pressure adjusting operation by the APC  276 , flow rate adjusting operations for the process gases by the MFCs  243   c ,  244   c ,  245   c ,  246   c ,  247   c  and  248   c  and the valves  243   d ,  244   d ,  245   d ,  246   d ,  247   d  and  248   d , an elevating and rotating operation for the substrate support  210  by the elevator  218 , a supplying and discharging operation and a vacuum-exhausting operation for the coolant to the coolant flow path by the temperature sensors  516 ,  517 ,  518 ,  519 ,  520  and  521 , the valves  310   b ,  311   b  and  312   b  and the vacuum pump  311   c , and a temperature elevating and lowering operation for the process vessel  202  by the heaters  416 ,  419 ,  420  and  422 . 
     The controller  500  is not limited to a dedicated computer, and may be embodied by a general-purpose computer. For example, the controller  500  may be embodied by preparing an external memory  473  (for example, a magnetic tape, a magnetic disk such as a flexible disk and a hard disk, an optical disk such as a CD and a DVD, a magneto-optical disk such as an MO, a semiconductor memory such as a USB memory and a memory card) where the above-described program is stored and installing the program onto the general-purpose computer using the external memory  473 . A method of providing the program to the computer is not limited to using the external memory  473 . For example, the program may be supplied to the computer (general-purpose computer) using communication means such as the Internet and a dedicated line instead of the external memory  473 . Further, the memory  500   c  or the external memory  473  may be embodied by a non-transitory computer readable recording medium. Hereafter, the memory  500   c  and the external memory  473  may be collectively or individually referred to as a “recording medium”. In the present specification, the term “recording medium” may refer to the memory  500   c  alone, may refer to the external memory  473  alone or may refer to both of the memory  500   c  and the external memory  473 . 
     (5) Substrate Processing 
     Hereinafter, as a part of a manufacturing process of a semiconductor device, a process (that is, the substrate processing) of forming a film on the wafer  200  using the process vessel  202  will be described. In the following description, the operations of the components constituting the substrate processing apparatus  10  are controlled by the controller  500 . 
     In the following description, an example of forming a silicon nitride film (also simply referred to as an “SiN film”) serving as the film on the wafer  200  by alternately supplying the first element-containing gas (first process gas) and the second element-containing gas (second process gas) to the wafer  200  will be described. For example, a silicon-containing gas obtained by vaporizing hexachlorodisilane (Si2Cl6, abbreviated as HCDS) gas is used as the first element-containing gas, and the NH3 gas is used as the second element-containing gas. 
       FIG.  4    is a flowchart schematically illustrating the substrate processing according to the embodiments of the present disclosure. 
     &lt;Temperature Elevating Step: S 10 &gt; 
     In the temperature elevating step S 10 , the inner temperature of the process vessel  202  is elevated while the wafer  200  is not supported by the substrate support  210 . 
     In the temperature elevating step S 10 , it is preferable to safely prevent the outside of the process vessel  202  from entering the high temperature state. Therefore, in the temperature elevating step S 10 , the controller  500  turns on the power of each of the heaters  416 ,  419 ,  420 ,  422  and  213  while maintaining insides of the piping structures  316 ,  319 ,  320 ,  321  and  322  in a vacuum state. Further, with the valves  310   b  and  312   b  closed and the valve  311   b  open, the vacuum pump  311   c  is operated to vacuum-exhaust (evacuate) the insides of the piping structures  316 ,  319 ,  320 ,  321  and  322 . That is, the coolant flow path is vacuum-exhausted to perform the temperature elevating step S 10 . Therefore, the coolant flow path is used as a vacuum heat insulator such that it is possible to prevent the heat inside the process vessel  202  from being released to the outside of the process vessel  202 . It is also possible to shorten an amount of time taken to elevate a temperature up to the first temperature (which is the film-forming temperature). In addition, since the coolant flow path is provided between the heater and each 0-ring, it is possible to reduce the heat conduction from each heater to the coolant flow path, and as a result, it is possible to prevent (or suppress) the O-ring from deteriorating. 
     For example, a distance between the substrate placing surface  211  and the shower head  230  in the temperature elevating step S 10  is set to be greater than the distance between the substrate placing surface  211  and the shower head  230  in the film-forming step S 12  described later. Thereby, it is possible to reduce an influence of the heater  213  provided at the substrate support  210 , and as a result, it is also possible to suppress a temperature elevation of the shower head  230  due to the heat generated by the heater  213 . 
     &lt;Substrate Loading, Placing and Heating Step: S 11 &gt; 
     In the substrate loading, placing and heating step S 11 , first, the substrate mounting table  212  in the process vessel  202  is lowered to the wafer transfer position such that the lift pins  207  penetrate the through-holes  214  of the substrate mounting table  212 . As a result, the lift pins  207  protrude from a surface of the substrate mounting table  212  by a predetermined height. Subsequently, the gate valve  205  is opened such that the transfer space  203  communicates with the first transfer chamber  103 . Then, the wafer  200  is transferred (loaded) into the transfer space  203  using the first substrate transfer device  112  provided in the first transfer chamber  103  such that the wafer  200  is placed onto the lift pins  207 . As a result, the wafer  200  is supported in a horizontal orientation on the lift pins  207  protruding from the surface of the substrate mounting table  212 . 
     After the wafer  200  is loaded into the process vessel  202  (that is, into the first transfer chamber  103 ), the first substrate transfer device  112  is retracted to the outside of the process vessel  202 , and the gate valve  205  is closed to seal (close) the inside of the process vessel  202  hermetically. Thereafter, by elevating the substrate mounting table  212 , the wafer  200  is placed on the substrate placing surface  211  of the substrate mounting table  212 . By further elevating the substrate mounting table  212 , the wafer  200  is elevated to the processing position (wafer processing position) in the process space  201  described above. 
     After the wafer  200  is loaded into the transfer space  203  and elevated to wafer the processing position in the process space  201 , the valve  277  and the valve  275  are opened to communicate the process space  201  with the APC  276  and the APC  276  with the vacuum pump  278 . 
     By adjusting the conductance of the exhaust pipe  263 , the APC  276  controls (adjusts) an exhaust flow rate of the process space  201  by the vacuum pump  278 , and maintains the inner pressure of the process space  201  at a predetermined pressure (for example, a high vacuum of 10-5 Pa to 10-1 Pa). 
     In the substrate loading, placing and heating step S 11 , the inner pressure of the process space  201  is adjusted to the predetermined pressure, and the heater  213  is controlled such that a surface temperature of the wafer  200  is adjusted to a temperature at which the wafer  200  is processed (that is, the first temperature). For example, the first temperature is set to a temperature within a range from 700° C. to 1,000° C., specifically 800° C. to 900° C. According to the present embodiments, the first temperature refers to a temperature at which the film such as the SiN film can be formed in the film-forming step S 12  described later. In addition, in the present specification, for example, a numerical range such as “700° C. to 1,000° C.” refers to a range that a lower limit and an upper limit are included in the numerical range. Therefore, for example, the numerical range “700° C. to 1,000° C.” means a range equal to or more than 700° C. and equal to or less than 1,000° C. The same also applies to other numerical ranges described herein. 
     &lt;Film-forming Step: S 12 &gt; 
     Subsequently, the film-forming step S 12  is performed. Hereinafter, the film-forming step S 12  will be described in detail with reference to  FIG.  5   . As the film-forming step S 12 , a cyclic process may be performed by repeating alternately supplying different process gases (that is, by repeatedly and alternately performing a first process gas supply step S 20  and a second process gas supply step S 22  described later). 
     Further, in the film-forming step S 12 , the wafer  200  is heated to the first temperature while the wafer  200  is supported by the substrate support  210 , and the process gases are supplied into the process vessel  202  accommodating the substrate support  210 . Therefore, the film-forming step S 12  may also be referred to as a “process gas supply step”. In addition, the process gases may also be collectively or individually referred to as the “process gas”. 
     Further, the film-forming step S 12  is performed in a state in which the corrosion prevention coating is performed on a region of the shower head  230  (which is made of a material susceptible to corrosion by the process gases) in contact with the process gases. In addition, similar to the shower head  230 , the film-forming step S 12  is performed in a state in which the low temperature structure such as the shaft  217  is coated by the corrosion prevention coating. 
     According to the present embodiments, in the film-forming step S 12 , the controller  500  operates the vacuum pump  311   c  with the valves  310   b  and  312   b  closed and the valve  311   b  open so as to vacuum-exhaust (evacuate) the insides of the piping structures  316 ,  319 ,  320 ,  321  and  322 . That is, the coolant flow path is vacuum-exhausted to perform the film-forming step S 12 . Therefore, the coolant flow path is used as the vacuum heat insulator such that it is possible to prevent the heat inside the process vessel  202  from being released to the outside of the process vessel  202 . In addition, in the film-forming step S 12 , as long as the temperature of the wafer  200  can be maintained at the first temperature, the power of each of the heaters  416 ,  419 ,  420  and  422  may be turned off. 
     &lt;First Process Gas Supply Step: S 20 &gt; 
     In the film-forming step S 12 , the first process gas supply step S 20  is performed first. When the silicon-containing gas serving as the first process gas (first element-containing gas) is supplied in the first process gas supply step S 20 , with the valve  243   d  open, the MFC  243   c  is controlled such that a flow rate of the silicon-containing gas is adjusted to a predetermined flow rate. As a result, a supply of the silicon-containing gas into the process space  201  is started. In addition, for example, a supply flow rate of the silicon-containing gas may be equal to or more than 100 sccm and equal to or less than 5,000 sccm. When supplying the silicon-containing gas, with the valve  248   d  of the third gas supplier  245  open, the N2 gas is supplied through the third gas supply pipe  245   a . In addition, the N2 gas may be flown through the first inert gas supplier. Further, prior to the film-forming step S 12 , a supply of N2 gas through the third gas supply pipe  245   a  may be started. 
     The silicon-containing gas supplied into the process space  201  is then supplied onto the wafer  200 . By the silicon-containing gas contacting the surface of the wafer  200 , a silicon-containing layer serving as a first element-containing layer is formed on the surface of the wafer  200 . 
     For example, the silicon-containing layer of a predetermined thickness and a predetermined distribution is formed according to the conditions such as an inner pressure of the process vessel  202  (that is, the inner pressure of the process space  201 ), the flow rate of the silicon-containing gas, a temperature of the substrate support (susceptor)  210  and a time taken for the silicon-containing gas to pass through the process space  201 . A predetermined film may be formed on the wafer  200  in advance. Further, a predetermined pattern may be formed in advance on the wafer  200  or the predetermined film. 
     After a predetermined time has elapsed from the start of the supply of the silicon-containing gas, the valve  243   d  is closed to stop the supply of the silicon-containing gas. For example, a supply time (time duration) of supplying the silicon-containing gas may be equal to or more than 2 seconds and equal to or less than 20 seconds. 
     In the first process gas supply step S 20 , with the valve  275  and the valve  277  open, the inner pressure of the process space  201  is controlled (adjusted) by the APC  276  to a predetermined pressure. 
     &lt;Purge Step: S 21 &gt; 
     After the supply of the silicon-containing gas is stopped, the N2 gas is supplied through the third gas supply pipe  245   a  to purge the process space  201 . In the purge step S 21 , with the valve  275  and the valve  277  open, the inner pressure of the process space  201  is controlled (adjusted) by the APC  276  to a predetermined pressure. As a result, the silicon-containing gas that could not be bonded to the wafer  200  in the first process gas supply step S 20  is removed from the process space  201  by the vacuum pump  278  through the exhaust pipe  263 . 
     In the purge step S 21 , a large amount of the purge gas may be supplied to improve an exhaust efficiency in order to remove the silicon-containing gas remaining in the wafer  200 , the process space  201  and the shower head buffer chamber  232 . 
     After the process space  201  is sufficiently purged, the pressure control by the APC  276  is resumed with the valve  275  and the valve  277  open. Further, the N2 gas may be continuously supplied through the third gas supply pipe  245   a  to purge the shower head  230  and the process space  201 . 
     &lt;Second Process Gas Supply Step: S 22 &gt; 
     After the shower head buffer chamber  232  and the process space  201  are purged, the second process gas supply step S 22  is subsequently performed. In the second process gas supply step S 22 , with the valve  244   d  open, a supply of the NH3 gas serving as the second process gas (second element-containing gas) into the process space  201  through the shower head  230  is started. In the second process gas supply step S 22 , the MFC  244   c  is controlled such that a flow rate of the NH3 gas is adjusted to a predetermined flow rate. For example, a supply flow rate of the NH3 gas may be equal to or more than 1,000 sccm and equal to or less than 10,000 sccm. In addition, in the second process gas supply step S 22 , with the valve  248   d  of the third gas supplier  245  open, the N2 gas is supplied through the third gas supply pipe  245   a . By supplying the N2 gas through the third gas supply pipe  245   a , it is possible to prevent the NH3 gas from entering the third gas supplier  245 . 
     The NH3 gas is supplied into the process space  201  through the shower head  230 . The NH3 gas supplied into the process space  201  reacts with the silicon-containing layer on the wafer  200 . Thereby, the silicon-containing layer formed on the wafer  200  is modified by the NH3 gas. As a result, for example, a silicon nitride layer (also simply referred to as an “SiN layer”) containing silicon (Si) and nitrogen (N) is formed on the wafer  200 . 
     After a predetermined time has elapsed from the start of the supply of the NH3 gas, the valve  244   d  is closed to stop the supply of the NH3 gas. For example, a supply time (time duration) of supplying the NH3 gas may be equal to or more than 2 seconds and equal to or less than 20 seconds. 
     In the second process gas supply step S 22 , similar to the first process gas supply step S 20 , the inner pressure of the process space  201  is controlled (adjusted) by the APC  276  to become a predetermined pressure with the valve  275  and the valve  277  open. 
     &lt;Purge Step S 23 &gt; 
     After the supply of the NH3 gas is stopped, the purge step S 23  similar to the purge step S 21  described above is performed. The operations of the components of the substrate processing apparatus  10  in the purge step S 23  is similar to those of the components in the purge step S 21 . Therefore, the detailed descriptions of the purge step S 23  are omitted. 
     &lt;Determination Step: S 24 &gt; 
     In the determination step S 24 , the controller  500  determines whether a cycle including the first process gas supply step S 20 , the purge step S 21 , the second process gas supply step S 22  and the purge step S 23  has been performed a predetermined number of times (n times). By performing the cycle the predetermined number of times, the SiN layer of a desired thickness is formed on the wafer  200 . 
     After the film-forming step S 12  constituted by the first process gas supply step S 20 , the purge step S 21 , the second process gas supply step S 22  and the purge step S 23  is performed the predetermined number of times (n times), a substrate unloading step S 13  is performed. 
     &lt;Substrate Unloading Step: S 13 &gt; 
     In the substrate unloading step S 13 , the processed wafer  200  is transferred (unloaded) out of the process vessel  202  in the order reverse to that of the substrate loading, placing and heating step S 11 . 
     &lt;Determination Step: S 14 &gt; 
     In the determination step S 14 , the controller  500  determines whether a cycle including the substrate loading, placing and heating step S 11 , the film-forming step S 12  and the substrate unloading step S 13  has been performed a predetermined number of times (m times). When it is determined, in the determination step S 14 , that the cycle has not been performed the predetermined number of times (m times) (“NO” in  FIG.  4   ), the substrate loading, placing and heating step S 11 , the film-forming step S 12  and the substrate unloading step S 13  are performed again to process a next wafer (unprocessed wafer)  200 . When it is determined, in the determination step S 14 , that the cycle has been performed the predetermined number of times (m times) (“YES” in  FIG.  4   ), a temperature lowering step S 15  is subsequently performed. By performing the cycle the predetermined number of times (m times), the SiN film of a desired thickness is formed on the wafer  200  and the locations such as the wall surface of the process vessel  202 . 
     &lt;Temperature Lowering Step: S 15 &gt; 
     In the temperature lowering step S 15 , while the wafer  200  is not supported by the substrate support  210 , the coolant is supplied into the piping structures  316 ,  317 ,  318 ,  319 ,  320 ,  321  and  322  for a predetermined time. That is, by supplying the coolant to the coolant flow path for the predetermined time, a temperature of the low temperature structure such as the shower head  230  and the shaft  217  and the inner temperature of the process vessel  202  are lowered to a predetermined temperature. 
     That is, in the temperature lowering step S 15 , the coolant is supplied to the coolant flow path provided in the process vessel  202  for the predetermined time after the film forming step S 12 . As a result, the temperature of the low temperature structure such as the shower head  230  and the shaft  217  is lowered to a second temperature lower than the first temperature and at which the coating does not deteriorate. 
     In the temperature lowering step S 15 , with the power of each of the heaters  213 ,  416 ,  419 ,  420  and  422  turned off, the valves  310   b  and  312   b  open and the valve  311   b  closed, the controller  500  controls the coolant gas supplier  310   a  to supply the coolant to the coolant flow path. The coolant supplied through the coolant gas supplier  310   a  is discharged to an outside of the substrate processing apparatus  10  through the supply pipe  310 , the valve  310   b , the piping structures  319 ,  316 ,  320 ,  321 , and  322 , the discharge pipe  311 , the pipe  312  and the valve  312   b . That is, in the temperature lowering step S 15 , the coolant is supplied to the coolant flow path through the coolant gas supplier  310   a  to cool the vicinities of the piping structures  319 ,  316 ,  317 ,  318 ,  320 ,  321  and  322 . In the temperature lowering step S 15 , when the inner temperature of the process vessel  202  is lowered to the second temperature based on the temperature information detected by the temperature sensors  516  through  521 , the valves  310   b  and  312   b  are closed to stop the supplying and discharging operation of the coolant to the coolant flow path. As a result, it is possible to shorten an amount of time taken to lower a temperature down to the second temperature (which is a cleaning temperature). 
     For example, the distance between the substrate placing surface  211  and the shower head  230  in the temperature lowering step S 15  may be set to be greater than the distance between the substrate placing surface  211  and the shower head  230  in the film-forming step S 12  described above. Thereby, it is possible to reduce the influence of the heater  213  provided at the substrate support  210 , and as a result, it is also possible to suppress the temperature elevation of the shower head  230  due to the heat generated by the heater  213  or accumulated in the substrate mounting table  212 . 
     &lt;Cleaning Step: S 16 &gt; 
     In the cleaning step S 16 , the cleaning gas is supplied into the process vessel  202 . That is, while the wafer  200  is not supported by the substrate support  210 , the cleaning gas is supplied into the process vessel  202  to clean the process vessel  202 . In the cleaning step S 16 , for example, the inner temperature of the process space  201  (that is the inner temperature of the process vessel  202 ) is set to a temperature within a range from 100° C. to 500° C., specifically 300° C. to 500° C. 
     Specifically, the cleaning gas is supplied through the third gas supply pipe  245   a  to clean an inside of the shower head  230  or the inside of the process vessel  202 . That is, in the cleaning step S 16 , with the valve  245   d  open, the MFC  245   c  is controlled such that a flow rate of the cleaning gas becomes a predetermined flow rate. As a result, a supply of the cleaning gas into the process space  201  is started. When supplying the cleaning gas, with the valve  275  and the valve  277  open, the inner pressure of the process space  201  is controlled (adjusted) by the APC  276  to a predetermined pressure. As a result, the deposits remaining in locations such as the inside of the shower head  230 , the substrate support  210  and an inner wall of the process vessel  202  are removed from the process space  201  by the vacuum pump  278  through the exhaust pipe  263 . 
     That is, after the temperature lowering step S 15 , while the wafer  200  is not supported by the substrate support  210 , the cleaning gas is supplied into the process vessel  202  in the cleaning step S 16  to clean the locations such as the inside of the shower head  230 , the shaft  217  and the inner wall of the process vessel  202 . 
     According to the present embodiments, in the cleaning step S 16 , the controller  500  operates the vacuum pump  311   c  with the power of each of the heaters  416 ,  419 ,  420  and  422  turned off, the valves  310   b  and  312   b  closed and the valve  311   b  open so as to vacuum-exhaust (evacuate) the insides of the piping structures  316 ,  319 ,  320 ,  321  and  322 . That is, the coolant flow path is vacuum-exhausted to perform the cleaning step S 16 . Therefore, the coolant flow path is used as the vacuum heat insulator. 
     &lt;Determination Step: S 17 &gt; 
     After the cleaning step S 16 , the determination step S 17  is performed. In the determination step S 17 , when a next wafer  200  to be processed exists (“YES” in  FIG.  4   ), the temperature elevating step S 10  through the cleaning step S 16  are performed again, and when the next wafer  200  to be processed does not exist (“NO” in  FIG.  4   ), the substrate processing is terminated. 
     OTHER EMBODIMENTS 
     While the technique of the present disclosure is described in detail by way of the above-described embodiments, the technique of the present disclosure is not limited thereto. The technique of the present disclosure may be modified in various ways without departing from the scope thereof. 
     For example, the above-described embodiments are described by way of an example in which the SiN film is formed on the wafer  200  by alternately supplying, in the film-forming step S 12  performed by the substrate processing apparatus  10 , the silicon-containing gas serving as the first element-containing gas (first process gas) and the NH3 gas serving as the second element-containing gas (second process gas). However, the technique of the present disclosure is not limited thereto. For example, the process gases used in the film-forming step are not limited to the silicon-containing gas and the NH3 gas. That is, the technique of the present disclosure may also be applied to other film-forming steps wherein other gases are used to form different films, or three or more different process gases are non-simultaneously supplied to form a film. Specifically, instead of silicon, for example, an element such as titanium (Ti), zirconium (Zr) and hafnium (Hf) may be used as the first element. In addition, instead of nitrogen (N), for example, an element such as oxygen (O) may be used as the second element. 
     In addition, the above-described embodiments are described by way of an example in which the supply pipe  310  through which the coolant is supplied is connected to the upstream end of the coolant flow path configured by connecting the piping structures  316 ,  319 ,  320 ,  321  and  322 , and the discharge pipe  311  through which the coolant is discharged to the outside of the process vessel  202  is connected to the downstream end of the coolant flow path configured by connecting the piping structures  316 ,  319 ,  320 ,  321  and  322 . However, the technique of the present disclosure is not limited thereto. For example, the supply pipe  310  through which the coolant is supplied is connected to each upstream end of the piping structures  316  through  322 , and the discharge pipe  311  through which the coolant is discharged to the outside of the process vessel  202  is connected to each downstream end of the piping structures  316  through  322 . Thereby, it possible to shorten a cooling time, and it is also possible to control the cooling and the heating in the vicinity of each coolant flow path configured by each piping structures  316  through  322 . 
     In addition, the above-described embodiments are described by way of the example in which the supply pipe  310  through which the coolant is supplied is connected to the upstream end of the coolant flow path configured by connecting the piping structures  316 ,  319 ,  320 ,  321  and  322 , and the discharge pipe  311  through which the coolant is discharged to the outside of the process vessel  202  is connected to the downstream end of the coolant flow path configured by connecting the piping structures  316 ,  319 ,  320 ,  321  and  322 . However, the technique of the present disclosure is not limited thereto. For example, a cooling apparatus (cooler) may be provided in the coolant flow path such that the coolant can be circulated while being cooled and without being discharged to the outside of the process vessel  202 . 
     In addition, the above-described embodiments are described by way of an example in which the film-forming step S 12  is performed while the power of each of the heaters  416 ,  419 ,  420  and  422  is turned off. However, the technique of the present disclosure is not limited thereto. For example, the film-forming step S 12  may be performed while the power of each of the heaters  416 ,  419 ,  420  and  422  is turned on. As a result, it is possible to heat the inside of the process vessel  202  from around the substrate support  210 . 
     In addition, the above-described embodiments are described by way of an example in which the coolant flow path is vacuum-exhausted (evacuated) in the film-forming step S 12  such that the coolant flow path is used as the vacuum heat insulator. However, the technique of the present disclosure is not limited thereto. For example, in the film-forming step S 12 , the coolant may be supplied to the coolant flow path provided in the shaft  205   b  of the gate valve  205  to cool the shaft  205   b.    
     According to some embodiments of the present disclosure, it is possible to shorten the downtime of the substrate processing apparatus and to improve the operating rate of the substrate processing apparatus.