Patent Publication Number: US-2020291516-A1

Title: Substrate processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-047056, filed on Mar. 14, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a substrate processing apparatus that performs a process such as heat treatment on a substrate such as a semiconductor substrate. 
     BACKGROUND 
     In an IC-manufacturing process of a related art, for example, a vertical type processing apparatus which mounts a plurality of substrates on a boat and simultaneously performs batch processing on the plurality of substrates has been used in order to perform heat treatment such as forming an insulating film, a metal film, a semiconductor film or the like on the substrates, or diffusing an impurity. 
     This vertical type processing apparatus includes a process chamber in which the substrates mounted on the boat are processed, and a substrate transfer chamber for transferring the substrates to the boat before the processing. The substrate transfer chamber is filled with, for example, a nitrogen gas as an inert gas, so that the oxygen concentration in the substrate transfer chamber is lowered to block the substrates from oxygen so as to suppress formation of a natural oxide film on the substrates. 
     In the conventional vertical type processing apparatus, however, when the oxygen concentration in the substrate transfer chamber is to be reduced, the pressure control of the substrate transfer chamber becomes unstable, which is a problem in improving the throughput of the apparatus. 
     SUMMARY 
     The present disclosure provides some embodiments of a technique capable of reducing an oxygen concentration in a housing and realizing stable pressure control of a substrate transfer chamber. 
     According to one or more embodiments of the present disclosure, there is provided a technique that includes: a substrate transfer chamber; a pod transfer chamber; a plurality of reinforcement structures installed along a wall of a housing constituting the substrate transfer chamber and forming a plurality of first confinement spaces between the reinforcement structures and the wall; a communication hole installed at each of the plurality of reinforcement structures so that a space in the housing and each of the plurality of first confinement spaces communicate with each other; a collecting pipe having the plurality of reinforcement structures connected in the housing and including a second confinement space communicating with the plurality of first confinement spaces; and a pressure regulator connected to the collecting pipe, and configured to perform a regulation so that a relationship of pressure is satisfied. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure. 
         FIG. 1  is a perspective view of a substrate processing apparatus. 
         FIG. 2  is a vertical cross sectional view of the substrate processing apparatus. 
         FIG. 3  is a view illustrating a reinforcement structure. 
         FIG. 4  is a view illustrating a reinforcement structure. 
         FIG. 5  is a view illustrating a reinforcement structure and a pressure regulator. 
         FIG. 6  is a view illustrating a reinforcement structure and a pressure regulator. 
         FIG. 7  is a view illustrating a pressure regulator. 
         FIG. 8  is a view illustrating a process furnace. 
         FIG. 9  is a diagram illustrating a controller. 
         FIG. 10  is a view illustrating a pressure regulator. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. 
     First Embodiments 
     A substrate processing apparatus according to first embodiments of the present disclosure will be described with reference to the drawings. In the present embodiments, the substrate processing apparatus is configured as, for example, a semiconductor manufacturing apparatus that performs a process in a method of manufacturing a semiconductor device (integrated circuit: IC).  FIG. 1  is a perspective view of the processing apparatus.  FIG. 2  is a side perspective view of the processing apparatus illustrated in  FIG. 1 .  FIGS. 3 to 7  are explanatory views illustrating details of a reinforcement structure of a substrate transfer chamber.  FIG. 8  is an explanatory diagram illustrating a controller that controls the substrate processing apparatus.  FIG. 9  is an explanatory view illustrating details of a process furnace  202 . 
     A substrate processing apparatus  100  uses pods  110  as substrate carriers which store substrates  200  made of silicon or the like, and includes a housing  111 . A pod-loading/unloading port  112  is installed at a front wall  111   a  of the housing  111  so as to communicate between the inside and the outside of the housing  111 , and is opened and closed by a front shutter  113 . A load port  114  is installed at a front side of the pod-loading/unloading port  112 , in which the pods  110  are held on the load port  114 . The pods  110  are loaded onto the load port  114  by an in-process transfer device (not shown), and are unloaded from the load port  114 . 
     A rotary shelf  105  is installed above a substantially central portion of the housing  111  in a longitudinal direction, in which the rotary shelf  105  rotates about a post  116  and stores a plurality of pods  110  in a shelf board  117 . 
     A pod transfer device  118  is installed between the load port  114  and the rotary shelf  105  in the housing  111 . The pod transfer device  118  includes a pod elevator  118   a  which can move up and down while holding the pods  110  and a pod transfer mechanism  118   b  as a horizontal transfer mechanism, and transfers the pods  110  among the load port  114 , the rotary shelf  105 , and pod openers  121 . A room in which the pod transfer device  118  is disposed will be referred to as a pod transfer chamber  126 . 
     A clean air unit  131  is installed at the ceiling of the housing  111 . Clean air as a purified inert gas is supplied from the clean air unit  131  to suppress the diffusion of dust in the housing  111 . An exhaust part  132  is installed at the bottom of the housing  111 . The exhaust part  132  will also be referred to as a transfer chamber system exhaust part. The inert gas supplied from the clean air unit  131  and the atmosphere in a confinement space as described hereinbelow are exhausted. 
     A sub-housing  119  is established below a substantially central portion of the housing  111  in the longitudinal direction over its rear end. A pair of substrate-loading/unloading ports  120  for loading and unloading the substrates  200  into and from the sub-housing  119  are installed at a front wall  119   a  of the sub-housing  119  to be vertically arranged in upper and lower two stages, and a pair of pod openers  121  are respectively installed at the upper and lower substrate-loading/unloading ports  120 . 
     The pod openers  121  each include a mounting table  122  on which the pod  110  is held, and a cap-attaching/detaching mechanism  123  for attaching and detaching a cap (lid) of the pod  110 . The pod opener  121  is configured to open and close a substrate-loading/unloading port of the pod  110  by attaching and detaching the cap of the pod  110  held on the mounting table  122  by the cap-attaching/detaching mechanism  123 . The mounting table  122  is a transfer shelf on which a substrate accommodator is held when the substrates are transferred. 
     As illustrated in  FIG. 1 , the sub-housing  119  constitutes a substrate transfer chamber  124  isolated from the atmosphere in a space in which the pod transfer device  118  and the rotary shelf  105  are installed. A substrate transfer mechanism  125  which transfers the substrates stored in the pods  110  to a boat  217  as a substrate support is installed in a front region in the substrate transfer chamber  124 . The substrate transfer mechanism  125  constitutes a substrate transfer device as a substrate transfer means. The substrate transfer mechanism  125  includes a substrate transfer device  125   a  configured to rotate or linearly drive the substrates  200  in the horizontal direction by mounting them on tweezers  125   c,  and a substrate transfer device elevator  125   b  for moving the substrate transfer device  125   a  up and down. By the continuous operation of the substrate transfer device elevator  125   b  and the substrate transfer device  125   a,  the substrates  200  are charged and discharged on and from the boat  217 . 
     A clean unit  134  formed of a supply fan and a dustproof filter is installed in the substrate transfer chamber  124  so as to supply clean air  133  which is a cleaned inert gas. The clean unit  134  will also be referred to as an inert gas supply part or a substrate transfer chamber system inert gas supply part. 
     The clean unit  134  constitutes an inert gas supply part for supplying an inert gas to the substrate transfer chamber  124 . In addition, an exhaust part  127  configured to exhaust an internal atmosphere of the substrate transfer chamber  124  to the outside of the substrate transfer chamber  124  is installed at the substrate transfer chamber  124 . The exhaust part  127  is configured to return a portion of the atmosphere exhausted to the outside of the substrate transfer chamber  124  to the clean unit  134  for circulation, and to exhaust the remainder to the outside of the substrate processing apparatus  100 . The exhaust part  127  will also be referred to as a substrate transfer chamber system exhaust part. 
     As illustrated in  FIG. 2 , the process furnace  202  is installed above the boat  217 . The process furnace  202  includes a reaction tube  201  as described hereinbelow therein, and a heater  211  for heating the interior of the reaction tube  201  around the reaction tube  201 . The lower end of the process furnace  202  is opened and closed by a furnace-opening cap  147 . Details of the process furnace  202  will be described below. 
     As illustrated in  FIG. 1 , a boat elevator  115  for moving the boat  217  up and down is installed in the substrate transfer chamber  124 . The boat elevator  115  constitutes a substrate support (boat) transfer machine as a substrate support transfer means. A seal cap  219  is horizontally installed at an arm  128  connected to the boat elevator  115 , and is configured to vertically support the boat  217  and seal the lower end of the process furnace  202 . 
     The boat  217  includes a plurality of holding members, and is configured to support a plurality of substrates  200 , e.g., about 50 to 125 substrates, in a horizontal posture in such a state that the substrates  200  are arranged along the vertical direction with the centers of the substrates  200  aligned with one another. 
     In addition, the substrate processing apparatus  100  according to the present embodiments includes a controller  300  (which will be described below) as a control means. The controller  300  is configured to control the entire substrate processing apparatus  100 , such as the gas flow rate control to the process furnace  202 , the pressure control in the process furnace  202 , the heater temperature control of the process furnace  202 , the driving control of the boat elevator  115  and the substrate transfer mechanism  125 , and the like, in the substrate processing apparatus  100 . 
     Next, a reinforcement structure according to the present embodiments and its surrounding structure will be described with reference to  FIGS. 3 to 7 . Further, α and α′ in  FIGS. 3 to 6  indicate the direction of α and the direction of α′ in  FIG. 2 . 
     The sub-housing  119  constitutes the substrate transfer chamber  124  as described above. In the present embodiments, the substrate transfer chamber  124  is adjacent to the process furnace  202 . The substrate transfer chamber  124  is a substrate transfer chamber for transferring the substrates  200  between the boat  217  and the pods  110 , and is also a transfer chamber used for loading the boat  217  mounting the substrates  200  into and out of a process chamber. The substrate transfer chamber  124  has a sealed space for preventing formation of a natural oxide film on the substrates  200 , and has a structure filled with an inert gas, for example, a nitrogen (N 2 ) gas. Therefore, the sub-housing  119  is established to have an airtight structure which is kept at a positive pressure of about  50  Pa from the atmospheric pressure. 
     The substrate transfer chamber  124  has large volume for enclosing the boat  217 , the clean air unit  134 , the substrate transfer device  125   a,  and the like, but has a structure in which plates such as stainless steel or the like are combined to reduce its weight. Therefore, reinforcement structures  141  are installed at the wall of the substrate transfer chamber  124 . 
     The reinforcement structures  141  will be described with reference to  FIGS. 3, 4, 5, and 6 .  FIG. 3  is a cross sectional view taken along a dotted line α-α′ in  FIG. 2 . The configuration of the clean air unit  134  and the like will be omitted for convenience of description.  FIG. 4  is a view illustrating a cutting portion of  FIG. 3  as a perspective view.  FIGS. 5 and 6  are views illustrating an entire sidewall of the substrate transfer chamber  124  and its surrounding structure. 
     A plurality of reinforcement structures  141  are arranged along a wall  140  of the substrate transfer chamber  124 . The position and number of arrangements are appropriately adjusted according to the strength of other components to be arranged and the substrate transfer chamber  124 . In  FIGS. 3 and 4 , two reinforcement structures  141  are arranged along the wall  140  as an example. As illustrated in  FIG. 5 , the reinforcement structures  141  are arranged to extend in the vertical direction on the wall  140  at a lateral side of the substrate transfer chamber  124 . 
     As illustrated in  FIG. 6 , a collecting pipe  151  is further installed above the reinforcement structure  141  at the substrate transfer chamber  124 . The collecting pipe  151  is installed along an upper wall  140   a  in  FIG. 5 , and is arranged to extend in the horizontal direction. In  FIG. 6 , one reinforcement structure  141  is illustrated for convenience of description, but the collecting pipe  151  is also connected to the other reinforcement structure  141 . With this arrangement, the strength of the substrate transfer chamber  124  is improved. 
     The reinforcement structure  141  has a U-shaped main structure  142  (which includes, for example side portions and a connection portion that is interposed between the side portions and arranged to be perpendicular to the side portions) and a flange  143  to maintain the strength. The reinforcement structure  141  is fixed to the wall  140  by welding the flange  143  to the wall  140 . A confinement space  144  is formed between the main structure  142  and the wall  140 . The confinement space  144  will also be referred to as a first confinement space. A communication hole  145  is formed at the main structure  142  to communicate the confinement space  144  with the internal space of the substrate transfer chamber  124 . 
     The confinement space  144  communicates with a confinement space  153  in the collecting pipe  151 . The collecting pipe  151  has, for example, a tubular structure  152  having a cavity therein. The cavity in the tubular structure  152  will be referred to as the confinement space  153 , in which the confinement space  153  communicates with the confinement space  144 . The confinement space  153  will also be referred to as a second confinement space. Also, as the reinforcement structure, a reinforcement structure using the same main structure and flange as those of the reinforcement structure  141  may be used. 
     Meanwhile, it is necessary to remove the oxygen components in the substrate transfer chamber  124  as described above. For example, it is desirable that the oxygen concentrations in the substrate transfer chamber  124  be 3 ppm or lower. 
     Most of the oxygen components are removed by the clean air  133  supplied from the clean unit  134 . However, there is a problem that it is difficult to remove the oxygen components in the confinement spaces  144  and  153 . This is because the confinement space  144  is covered with the main structure  142  and the confinement space  153  is covered with the tubular structure  152  to make it difficult for the clean air  133  to reach each space. Therefore, much time is required to reduce the oxygen components to a desired concentration or lower. 
     Furthermore, as another method of reducing the oxygen concentration, it may also be considered that the space between the confinement space  144  and the substrate transfer chamber  124  and the space between the confinement space  153  and the substrate transfer chamber  124  are completely isolated from each other. However, since the flange  143  is only welded to the wall  140 , there is a problem that oxygen enters the substrate transfer chamber  124  from each confinement space via the welded portion, and as a result, the oxygen concentration in the substrate transfer chamber  124  is increased. Therefore, it is difficult to lower the oxygen concentration even if the isolation is attempted by welding. 
     In addition, a method of communicating the confinement space  144  with a pump may be considered as in the related art. However, although the oxygen component concentration may be early reduced to a desired value or lower, the internal atmosphere of the substrate transfer chamber  124  may also be quickly exhausted by the pump through the confinement space  144 , making it difficult to regulate the pressure of the substrate transfer chamber  124 . Furthermore, there is a problem that the clean air  133  may be discharged and unnecessarily wasted. 
     Therefore, in the present technique, as illustrated in  FIGS. 5 and 6 , a pressure regulator  160  for controlling the pressures of the confinement space  144  and the confinement space  153  is installed. Details thereof will be described below. 
     As illustrated in  FIGS. 5 and 6 , the communication hole  145  is formed at a lower side of the reinforcement structure  141 . The upper end of the reinforcement structure  141  is connected to the collecting pipe  151 , and the confinement space  144  and the confinement space  153  communicate with each other. As will be described below, the inert gas in the substrate transfer chamber  124  is moved from the substrate transfer chamber to the pod transfer chamber  126  via the reinforcement structure  141 , the collecting pipe  151 , and the pressure regulator  160 . That is, the communication hole  145  is formed at the upstream side of the inert gas flow in the reinforcement structure  141 . 
     The collecting pipe  151  extends toward the pod transfer chamber  126  along the upper wall  140   a.  The pressure regulator  160  is installed at the pod transfer chamber  126 , and the collecting pipe  151  is connected to the pressure regulator  160 . Thus, the confinement space  153  and a buffer space  161  in the pressure regulator  160  communicate with each other. A communication hole  162  is formed at the pressure regulator  160 . 
     As illustrated in  FIGS. 5 and 7 , a pressure regulation structure  163  is installed at the pressure regulator  160 . The pressure regulation structure  163  is a box-shaped structure having a space therein. The internal space of the pressure regulation structure  163  communicates with the buffer space  161  via the communication hole  162 . 
     A hole  165  is formed at the pressure regulation structure  163  to allow the internal space of the pressure regulation structure  163  to communicate with the atmosphere of the pod transfer chamber  126 . A slide type lid  166  is installed near the hole  165  so that the degree of opening of the hole  165  can be controlled. 
     By controlling the opening degree of the hole  165 , the pressure is regulated to gradually decrease toward the downstream, such as in the following way: “pressure of the substrate transfer chamber  124 &gt;pressure of the confinement space  144 &gt;pressure of the confinement space  153 &gt;pressure of the pod transfer chamber  126 .” Since it is configured to cope with without directly connecting a device for rapidly reducing the pressure, such as the pump, it is possible to realize a gentle pressure gradient. Therefore, the pressures of the first confinement space and the second confinement space can be kept at predetermined values. Thus, the pressure regulation of the substrate transfer chamber  124  communicating with them is facilitated. 
     In addition, since it is configured to communicate with the atmosphere of the pod transfer chamber  126 , the oxygen components in each confinement space are exhausted from the exhaust part  132 . That is, the exhaust process can be completed in the substrate processing apparatus  100 . Since the atmosphere of the substrate transfer chamber  124  is not exhausted to the outside of the substrate processing apparatus  100 , it is possible to more reliably secure the safety of a person staying around the substrate processing apparatus  100 . 
     (Process Furnace) 
     Next, details of the process furnace  202  described above will be described with reference to  FIG. 8 . 
       FIG. 8  is a vertical cross sectional view illustrating a configuration example of the process furnace used in the substrate processing apparatus. 
     The process furnace  202  includes a reaction tube  201 . The reaction tube  201  is made of a heat resistant non-metallic material such as, e.g., quartz (SiO 2 ) or silicon carbide (SiC), and has a cylindrical shape with its upper end closed and its lower end opened. The lower end thereof is supported by a manifold  205 . A space formed inside the reaction tube  201  and the manifold  205  will be referred to as a process space  203 . The reaction tube  201  and the manifold  205  will be generally referred to as the process chamber. 
     A furnace opening is formed at the manifold  205 . The furnace opening is an entrance through which the boat  217  passes when it is inserted into the process space  203 . The manifold, the furnace opening, and the like will be generally referred to as a furnace opening part. 
     It is configured so that the substrates  200  supported by the boat  217  in a horizontal posture are accommodated in the process space  203  to be arranged along a vertical direction and in multiple stages. The boat  217  accommodated in the process space  203  is configured to be rotatable by rotating a rotary shaft  206  by a rotation mechanism  204 , with the plurality of substrates  200  mounted thereon, while maintaining hermeticity in the process space  203 . 
     The manifold  205  is disposed below the reaction tube  201  in a concentric relationship with the reaction tube  201 . The manifold  205  is made of a metal material, e.g., stainless steel or the like, and has a cylindrical shape with its upper and lower ends opened. The reaction tube  201  is vertically supported by the manifold  205  from the lower end side. That is, the reaction tube  201  forming the process space  203  is vertically erected via the manifold  205  so as to constitute the process furnace  202 . 
     The furnace opening is configured to be hermetically sealed by the seal cap  219  when the boat elevator (not shown) is raised. A seal member  207  such as an O-ring or the like for hermetically sealing the interior of the process space  203  is installed between the lower end of the manifold  205  and the seal cap  219 . 
     Furthermore, a gas introduction pipe  208  for introducing a processing gas, a purge gas, or the like into the process space  203  and an exhaust part  210  for exhausting a gas in the process space  203  are connected to the manifold  205 . The exhaust part  210  includes an exhaust pipe  210   a  and an APC (auto pressure controller)  210   b.  The exhaust part  210  will also be referred to as a process chamber system exhaust part. 
     The gas introduction pipe  208  is a nozzle. A plurality of gas supply holes are formed at the downstream side of the gas introduction pipe  208 , and it is configured so that the interior of the gas introduction pipe  208  communicates with the reaction tube  201 . The processing gas or the like is supplied from the gas supply holes to the process space  203 . 
     For example, two gas introduction pipes  208  are installed. In this case, one of them is a first gas introduction pipe  208   a  for supplying a precursor gas, and the other pipe is a second gas introduction pipe  208   b  for supplying a reaction gas reacting with the precursor gas. Although the two supply pipes are described herein, the number of supply pipes is not limited thereto but may be three or more depending on the type of process. 
     The gas introduction pipes  208  are connected to a processing gas transfer pipe  209  at the upstream side. The processing gas transfer pipe  209  is configured to transfer a gas from a gas source or the like to the gas introduction pipes  208 . A first processing gas transfer pipe  209   a  is connected to the first gas introduction pipe  208   a,  and a second processing gas transfer pipe  209   b  is connected to the second gas introduction pipe  208   b.  The connection between the gas introduction pipe  208  and the processing gas transfer pipe  209  will be described below. 
     An inert gas transfer pipe  213  is connected to the processing gas transfer pipe  209 . The inert gas transfer pipe  213  is configured to supply an inert gas to the processing gas transfer pipe  209 . The inert gas is, for example, a nitrogen (N 2 ) gas, and acts as a carrier gas for the processing gas or as a purge gas for the reaction tube  201 , the gas introduction pipe  208 , and the processing gas transfer pipe  209 . 
     A first inert gas transfer pipe  213   a  is connected to the first processing gas transfer pipe  209   a,  and a second inert gas transfer pipe  213   b  is connected to the second processing gas transfer pipe  209   b.    
     A mass flow controller  231  for controlling the supply amount of the processing gas and a valve  232  are installed at the first processing gas transfer pipe  209 . A mass flow controller  231   a  and a valve  232   a  are installed at the first processing gas transfer pipe  209   a.  A mass flow controller  231   b  and a valve  232   b  are installed at the processing gas transfer pipe  209   b.  The processing gas transfer pipe  209 , the processing gas transfer pipe  209   b,  the mass flow controller  231 , and the valve  232  will be generally referred to as a processing gas supply part. 
     A mass flow controller  233  for controlling the supply amount of the inert gas and a valve  234  are installed at the inert gas transfer pipe  213 . A mass flow controller  233   a  and a valve  234   a  are installed at the first inert gas introduction pipe  213   a.  A mass flow controller  233   b  and a valve  234   b  are installed at the second inert gas introduction pipe  213   b.  The inert gas transfer pipe  213 , the mass flow controller  231 , and the valve  234  will be generally referred to as a process chamber system inert gas supply part. 
     The processing gas supply part and the process chamber system inert gas supply part will be generally referred to as a process chamber system gas supply part. 
     The heater  211  as a heating means (heating mechanism) is disposed at the outer periphery of the reaction tube  201  to be concentric with the reaction tube  201 . The heater  211  is configured to heat the internal atmosphere of the process space  203  such that the interior of the process space  203  has a uniform or predetermined temperature distribution over the whole. 
     Next, the controller  300  for controlling operations of the respective parts described above will be described with reference to  FIG. 9 . The controller  300  is configured to control the overall operation of the substrate processing apparatus  100 . For example, the respective components of the substrate processing apparatus such as the transfer chamber system inert gas supply part, the transfer chamber system exhaust part, the substrate transfer chamber system inert gas supply part, the substrate transfer chamber system exhaust part, the process chamber system gas supply part, the process chamber system exhaust part, and the like are controlled by the controller  300 . 
       FIG. 9  is a block diagram schematically illustrating a configuration example of the controller of the substrate processing apparatus. The controller  300  may be configured as a computer including a CPU (central processing unit)  301 , a RAM (random access memory)  302 , a memory device  303 , and an I/O port  304 . The RAM  302 , the memory device  303 , and the I/O port  304  are configured to exchange data with the CPU  301  via an internal bus  305 . An input/output device  313  formed of, e.g., a touch panel or the like, and an external memory device  314  are configured to be connected to the controller  300 . Information may be input to the controller  300  from the input/output device  313 . Furthermore, the input/output device  313  is configured to display and output information under the control of the controller  300 . In addition, a network  312  is configured to be connected to the controller  300  via a receiving part  311 . This means that the controller  300  can also be connected to a higher device  320  such as a host computer or the like existing on the network  312 . 
     The memory device  303  is configured by, for example, a flash memory, a HDD (hard disk drive), or the like. A control program for controlling operations of the substrate processing apparatus  100 , a process recipe for specifying sequences and conditions of substrate processing, operation data or processing data generated during a process for setting the process recipe used for processing the substrates  200  is set, or the like is readably stored in the memory device  303 . The process recipe functions as a program for causing the controller  300  to execute each sequence in the substrate-processing process to obtain a predetermined result. Hereinafter, the process recipe and the control program will be generally and simply referred to as a “program.” Furthermore, when the term “program” is used herein, it may indicate a case of including only the process recipe, a case of including only the control program, or a case of including both the process recipe and the control program. The RAM  302  is configured as a memory area (work area) in which a program, operation data, or processing data read by the CPU  301  is temporarily stored. 
     The CPU  301  as an operation part is configured to read the control program from the memory device  303  and execute the same. The CPU  121   a  is also configured to read the process recipe from the memory device  303  according to an input of an operation command from the input/output device  313 . The CPU  301  is also configured to calculate operation data by comparing and operating a set value input from the receiving part  311  and the process recipe or control data stored in the memory device  303 . Furthermore, the CPU  301  is configured to execute a process of determining corresponding processing data (process recipe) from the operation data, and the like. In addition, the CPU  301  is configured to control, according to the contents of the process recipe thus read, the operations of the respective parts of the substrate processing apparatus  100 . 
     The controller  300  is not limited to a case of being configured as a dedicated computer, but may be configured as a general-purpose computer. For example, the controller  300  according to the present embodiments may be configured by installing, on the general-purpose computer, the aforementioned program stored in the external memory device  314  (for example, a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disc such as a CD or DVD, a magneto-optical disc such as a MO, or a semiconductor memory such as a USB memory or a memory card). However, means for supplying the program to the computer is not limited to the case of supplying it via the external memory device  314 . For example, the program may be supplied to the computer using a communication means such as the network  312  (the Internet or a dedicated line), instead of using the external memory device  314 . The memory device  303  or the external memory device  314  is configured as a non-transitory computer-readable recording medium. Hereinafter, the memory device  303  and the external memory device  314  will be generally and simply referred to as a “recording medium.” When the term “recording medium” is used herein, it may indicate a case of including only the memory device  303 , a case of including only the external memory device  314 , or a case of including both the memory device  303  and the external memory device  314 . 
     Next, an operation of the substrate processing apparatus  100  according to the present embodiments will be described. This operation is mainly controlled by the controller  300 . 
     The pod  110  is held on the mounting table  122 . The substrate-loading/unloading port  120  of the pod opener  121  is closed by the cap-attaching/detaching mechanism  123 . 
     When the substrate transfer chamber  124  is in a clean air atmosphere in advance by adjusting the lid  166  to adjust the opening degree of the hole  165 , it is set such that the relationship of “pressure of the substrate transfer chamber  124 &gt;pressure of the confinement space  144 &gt;pressure of the confinement space  153 &gt;pressure of the pod transfer chamber  126 ” is satisfied. 
     First, the clean air unit  131  and the exhaust part  132  are activated to supply clean air from the clean air unit  134  in a state in which there is no substrate  200  mounted on the boat  217 . Subsequently, the substrate transfer chamber  124  is set to the atmosphere of the clean air  133  by supplying the clean air  133  from the clean air unit  134  into the substrate transfer chamber  124 . 
     At this time, the exhaust part  127  is stopped. By stopping the exhaust part  127 , it is possible to easily achieve the relationship of “pressure of the substrate transfer chamber  124 &gt;pressure of the confinement space  144 &gt;pressure of the confinement space  153 &gt;pressure of the pod transfer chamber  126 ”. 
     Therefore, the clean air supplied to the confinement space  144  is moved to the pod transfer chamber  126  via the substrate transfer chamber  124 , the reinforcement structure  141 , the collecting pipe  151 , and the pressure regulator  160 , as illustrated by an arrow  135  in  FIG. 6 . That is, the oxygen components in the confinement space  144  and the confinement space  153  are transferred to the pod transfer chamber  126 . In this manner, the residual oxygen in the confinement space  144  and the confinement space  153  is exhausted. 
     The oxygen components exhausted to the pod transfer chamber  126  are exhausted from the exhaust part  132  of the pod transfer chamber  126 . When the oxygen components are exhausted from the confinement space  144  and the confinement space  153  and reach a predetermined concentration, the exhaust part  127  is activated to adjust the pressure of the substrate transfer chamber  124 . 
     Since the opening degree of the hole  165  is continuously maintained at this time, the reinforcement structure  141  and the collecting pipe  151  are filled with the clean air so that the predetermined pressure is kept. Thus, it is possible to easily regulate the pressure of the substrate transfer chamber  124  in a short time. 
     However, if the exhaust part  127  is operated while the oxygen components are being removed, the following problem may occur. When the exhaust part  127  is operated, the substrate transfer chamber  124  has a low pressure, and the oxygen components in the pod transfer chamber  126  may be moved to the substrate transfer chamber  124 . They may diffuse into the substrate transfer chamber  124 , making it impossible to remove the oxygen components. Therefore, it is desirable to stop the exhaust part  127 . 
     However, the exhaust part  127  may be operated as long as the relationship of “pressure of the substrate transfer chamber  124 &gt;pressure of the confinement space  144 &gt;pressure of the confinement space  153 &gt;pressure of the pod transfer chamber  126 ” can be satisfied. When the exhaust part  127  is operated, there is an effect that the oxygen components in the substrate transfer chamber  124  can be early removed. 
     Furthermore, the exhaust part  127  may be stopped when some oxygen components are removed from the substrate transfer chamber  124  by operating the exhaust part  127  firstly. Specifically, the oxygen components in the substrate transfer chamber  124  are removed from the substrate transfer chamber exhaust part while operating the exhaust part  127 , and after lapse of a predetermined time, the exhaust part  127  is stopped, and the residual oxygen in each space is exhausted from the confinement space  144  and the confinement space  153  to the pod transfer chamber  126 . By doing so, it is possible to early remove the oxygen components, and also to reliably remove the oxygen components from the confinement space. 
     Next, as illustrated in  FIG. 2 , the cap of the pod  110  held on the mounting table  122  is separated by the cap-attaching/detaching mechanism  123 , and the substrate-loading/unloading port of the pod  110  is opened. Furthermore, the substrate  200  is picked up from the pod  110  by the substrate transfer device  125   a  and is transferred to the boat  217  to be charged thereon. The substrate transfer device  125   a,  which has transferred the substrate  200  to the boat  217 , is returned to the pod  110  and charges a next substrate  200  on the boat  217 . 
     During the charging operation of the substrate  200  on the boat  217  by the substrate transfer device  125   a  at the one (upper or lower) pod opener  121 , another pod  110  is transferred from the rotary shelf  105  and the load port  114  to the other (lower or upper) pod opener  121  by the pod transfer device  118 , and the opening operation of the pod  110  by the pod opener  121  is simultaneously performed. 
     When a predetermined number of substrates  200  are charged on the boat  217 , the lower end of the process furnace  202  is opened by the furnace-opening cap  147 . Subsequently, the seal cap  219  is raised by the boat elevator  115 , and the boat  217  supported by the seal cap  219  is loaded into the reaction tube  201  in the process furnace  202 . 
     After the boat loading, the substrate processing as described hereinbelow is performed on the substrates  200  in the reaction tube  201 . After the processing, the boat  217  is unloaded from the reaction tube  201  by the boat elevator  115 , and the substrates  200  and the pods  110  are subsequently discharged to the outside of the housing  111  in reverse order. 
     Next, the substrate processing performed in the process furnace  202  will be described. Furthermore, the substrate processing according to the present embodiments is a method of forming a film on the surface of each of the substrates  200  by using, for example, a CVD (chemical vapor deposition) method, and is performed as one of the processes for manufacturing a semiconductor device. 
     A substrate-loading step S 10  will be described. First, the boat  217  supporting the plurality of substrates  200  as described above is lifted up by the boat elevator  115  and is loaded into the process space  203  (boat loading). In this state, the seal cap  219  seals the lower end of the manifold  205  via the O-ring  207 . 
     Next, a pressure-dropping/pressure-rising step S 20  will be described. The internal atmosphere of the process space  203  is exhausted from the exhaust part  210  so that the interior of the process space  203  has a desired pressure (degree of vacuum). The exhaust part  210  will also be referred to as a process chamber exhaust part. In this operation, the internal pressure of the process space  203  is measured, and the degree of opening of the APC valve  210   b  installed at the exhaust part  210  is feedback-controlled based on the measured pressure. Furthermore, the interior of the process space  203  is heated by the heater  211  to a desired temperature. In this operation, a state of supplying electric power to the heater  211  is feedback-controlled based on temperature information detected by a temperature sensor such that the interior of the process space  203  has a desired temperature distribution. In addition, the substrates  200  are rotated by rotating the boat  217  by the rotation mechanism  204 . 
     Next, a film-forming step S 30  will be described. At the film-forming step, a desired film is formed on the substrates  200  by supplying a gas thereto. 
     In the present embodiments, an example in which a hexachlorodisilane (Si 2 Cl 6 , also referred to as HCDS) is used as a first processing gas supplied from the first gas introduction pipe  208   a,  and an ammonia (NH 3 ) gas is used as a second processing gas supplied from the second gas introduction pipe  208   b  will be described. 
     The HCDS gas is supplied to the process space  203  via the first processing gas transfer pipe  209   a  and the first gas introduction pipe  208   a.  Furthermore, the NH 3  gas is supplied to the process space  203  via the second processing gas transfer pipe  209   b  and the second gas introduction pipe  208   b.    
     The HCDS gas and the NH 3  gas supplied to the process space  203  react with each other to form a silicon nitride film on the substrate  200 . 
     Next, a pressure-rising step S 40  will be described. When the film-forming step S 30  is completed, a purge gas is supplied into the process space  203  until the internal pressure of the process space  203  reaches an atmospheric pressure by reducing the opening degree of the APC valve  210   b.  The purge gas is, e.g., a N 2  gas, and is supplied to the process space via the inert gas transfer pipes  213   a  and  213 . 
     Next, a substrate-unloading step S 50  will be described. The film-formed substrate  200  is unloaded from the process space  203  in reverse order of the substrate-loading step S 10 . 
     Second Embodiments 
     Next, second embodiments will be described. The second embodiments differ from the first embodiments in the structure of the pressure regulation structure. Other components are similar to those of the first embodiments. Differences will be mainly described below. 
     The pressure regulator  160  of the present embodiments will be described with reference to  FIG. 10 . The pressure regulator  160  of the present embodiments includes a lower buffer space  171  communicating with the collecting pipe  151 . An upper buffer space  172  is installed on the lower buffer space  171 . A hole  173  is formed between the lower buffer space  171  and the upper buffer space  172 , through which they communicate. Furthermore, a hole  174  is formed at the upper buffer space  172 . The upper buffer space communicates with the pod transfer chamber  126  via the hole  174 . 
     A pressure regulation device  175  is installed at the hole  173 . The pressure regulation device  175  includes a shaft  175   a,  a valve body  175   b,  and a weight  175   c.  It is configured so that the shaft  175   a  is slidably supported and the valve body  175   b  opens and closes the hole  173 . The weight of the valve body  175   b  may be increased or decreased by changing the number and weight of weights  175   c.  This pressure regulation device  175  can regulate the internal pressure of the lower buffer space  171  to a pressure corresponding to a weight preset in the valve body  175   b  by self-control (self-alignment). 
     Since the opening degree of the hole  173  can be adjusted by the pressure regulation device  175 , pressures can be set to the following way: “pressure of the substrate transfer chamber  124 &gt;pressure of the confinement space  144 &gt;pressure of the confinement space  153 &gt;pressure of the pod transfer chamber  126 ” and it can be adjusted so that the pressure is reduced stepwise toward the downstream. Since it is configured here to cope with without directly connecting a device for rapidly reducing the pressure, such as the pump, it is possible to realize a gentle pressure gradient. Therefore, it is possible to keep the internal pressures of the first confinement space and the second confinement space at predetermined values. Thus, the pressure regulation of the substrate transfer chamber  124  communicating with them is facilitated. 
     According to the present disclosure in some embodiments, it is possible to realize a reduction in oxygen concentration in a housing and stable pressure control of a substrate transfer chamber. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.