Patent Publication Number: US-2022238359-A1

Title: Controlling method and substrate transport module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-010067, filed on Jan. 26, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a controlling method and a substrate transport module. 
     BACKGROUND 
     In an EFEM including a first chamber provided with an inlet into which a replacement gas is introduced and a second chamber provided with a transport robot, a technique for forming a predetermined pressure difference between the first chamber and the second chamber such that the pressure of the first chamber is higher than the pressure of the second chamber is known (see, for example, Patent Document 1). 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: Japanese Laid-Open Patent Publication No. 2018-160543 
       
    
     SUMMARY 
     A controlling method in accordance with an aspect of the present disclosure is a method of controlling a substrate transport module that includes a first chamber provided with a fan, a second chamber to which a replacement gas is sent from the first chamber by the fan and which includes a transporter configured to transport a substrate, a circulation line configured to communicate the first chamber and the second chamber with each other and circulate the replacement gas, and a valve provided in the circulation line. The method includes replacing an inside of the first chamber and an inside of the second chamber with the replacement gas by turning off the fan and closing the valve, and circulating the replacement gas through the circulation line by turning on the fan and opening the valve. The replacing includes controlling the fan to be turned on and the valve to be opened for a predetermined period of time. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure. 
         FIG. 1  is a view illustrating an example of a processing system according to an embodiment. 
         FIG. 2  is a view illustrating an example of a hardware configuration of a controller. 
         FIG. 3  is a view illustrating an example of a loader module. 
         FIG. 4  is a view illustrating another example of the loader module. 
         FIG. 5  is a diagram illustrating an example of a controlling method of an embodiment. 
         FIG. 6  is a view illustrating an example of operations of a valve and a circulation fan in the controlling method of  FIG. 5 . 
         FIG. 7  is a view illustrating another example of operations of the valve and the circulation fan in the controlling method of  FIG. 5 . 
         FIG. 8  is a diagram illustrating another example of the controlling method of the embodiment. 
     
    
    
     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. 
     Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all of the accompanying drawings, the same or corresponding members or components will be denoted by the same or corresponding reference numerals, and redundant explanations will be omitted. 
     [Processing System] 
     An example of a processing system of an embodiment will be described with reference to  FIGS. 1 and 2 .  FIG. 1  is a view illustrating an example of a processing system according to an embodiment.  FIG. 2  is a view illustrating an example of a hardware configuration of a controller. 
     A processing system  1  includes a transfer module  10 , four process modules  20 , a loader module  30 , two load-lock modules  40 , and a controller  100 . 
     The transfer module  10  has a substantially hexagonal shape in a plan view. The transfer module  10  is configured with a vacuum chamber and includes a transporter  11  arranged therein. The transporter  11  is formed by an articulated arm configured to be bent or stretched, raised or lowered, and swiveled at a position where the process modules  20  and the load-lock module  40  can be accessed. The transporter  11  includes two picks  12  that can be independently bent or stretched in opposite directions to transport two wafers W at a time. A wafer W is an example of a substrate. The transporter  11  is not limited to the configuration illustrated in  FIG. 1  as long as wafers W can be transported between the process modules  20  and the load-lock module  40 . 
     The process modules  20  are arranged radially around the transfer module  10  and are connected to the transfer module  10 . Each process module  20  is configured with a processing chamber and includes therein a columnar stage  21  on which a wafer W is placed. In the process module  20 , a predetermined process such as a film forming process is performed on the wafer W placed on the stage  21 . The transfer module  10  and the process modules  20  are partitioned by gate valves  22  that can be opened or closed. 
     The loader module  30  is an example of a substrate transport module, and is arranged to face the transfer module  10 . The loader module  30  has a rectangular parallelepiped shape and is a transport chamber in which oxygen concentration and humidity are controlled. A transporter  31  is arranged in the loader module  30 . The transporter  31  is slidably supported on a guide rail  32  that is provided in a central portion to extend within the loader module  30  along the longitudinal direction. A linear motor (not illustrated) including, for example, an encoder is built in the guide rail  32 , and thus the transporter  31  moves along the guide rail  32  by driving the linear motor. 
     The transporter  31  includes two articulated arms  33  arranged vertically in two levels as transport arms. A bifurcated pick  34  is installed at the tip end of each articulated arm  33 . A wafer W is held on each pick  34 . Each articulated arm  33  is configured to be bent or stretched and raised or lowered in the radial direction from the center. In addition, the bending and stretching motions of each articulated arm  33  can be individually controlled. Respective rotation shafts of the articulated arms  33  are coaxially and rotatably connected to a base  35  so that the rotation shafts can be rotated integrally, for example, in a swivel direction relative to the base  35 . The guide rail  32  and the articulated arms  33  function as drive mechanisms for moving the picks  34 . The transporter  31  transports wafers W among load-lock modules  40 , transport containers  51 , and an aligner  60 , which will be described later. The transporter  31  is not limited to the configuration illustrated in  FIG. 1  as long as wafers W can be transported among the load-lock modules  40 , the transport containers  51 , and the aligner  60 . 
     The aligner  60  is arranged in the loader module  30 . The aligner  60  performs alignment of a wafer W. The aligner  60  includes a rotation stage  61  configured to be rotated by a drive motor (not illustrated), and thus rotates in a state in which a wafer W is placed on the rotation stage  61 . An optical sensor (not illustrated) for detecting the peripheral edge of a wafer W is provided at outer periphery of the rotary stage  61 . The aligner  60  detects the center position of the wafer W and the direction of a notch with respect to the center of the wafer W by the optical sensor and adjusts the position for transporting the wafer W such that the center position of the wafer W and the direction of the notch in the load-lock module  40  are at a predetermined position and direction. 
     Two load-lock modules  40  are connected to one side surface of the loader module  30  in the longitudinal direction. Meanwhile, on the other side surface of the loader module  30  in the longitudinal direction, one or more carry-in ports  36  for introducing wafers W are provided. In the illustrated example, three carry-in ports  36  are provided. Each carry-in port  36  is provided with an opening or closing door  37  configured to be opened or closed. In addition, a load port  50  is provided to correspond to each carry-in port  36 . A transport container  51  for accommodating and transporting wafers W is placed on the load port  50 . The transport container  51  may be a front-opening unified pod (FOUP) in which a plurality of (e.g.,  25 ) wafers W are placed and accommodated in multiple levels at predetermined intervals. 
     A circulation part  330 , which will be described later, is provided on one side surface of the loader module  30  in the transverse direction. 
     Each load-lock module  40  is arranged between the transfer module  10  and the loader module  30 . The load-lock module  40  includes an internal pressure-variable chamber, the inside of which can be switched between vacuum and atmospheric pressure. Within each load-lock module  40 , a columnar stage  41  on which a wafer W is placed is provided. When the wafer W is carried from the loader module  30  into the transfer module  10 , the inside of the load-lock module  40  is maintained at atmospheric pressure to receive the wafer W from the loader module  30 , and is then decompressed to carry the wafer W into the transfer module  10 . When the wafer W is carried out from the transfer module  10  into the loader module  30 , the inside is maintained at vacuum to receive the wafer W from the transfer module  10 , and then the inside is boosted to atmospheric pressure to carry the wafer W into the loader module  30 . The load-lock module  40  and the transfer module  10  are partitioned by a gate valve  42  that can be opened or closed. The load-lock module  40  and the loader module  30  are partitioned by a gate valve  43  that can be opened or closed. 
     The controller  100  controls an operation of each component of the processing system  1 . As illustrated in  FIG. 2 , the controller  100  is a computer including a driver  101 , an auxiliary storage  102 , a memory  103 , a CPU  104 , an interface  105 , a display  106 , and the like, which are each connected to a bus  108  so as to be mutually connected. A program that implements a process in the controller  100  is provided by a recording medium  107  such as a CD-ROM. When the recording medium  107  storing the program is set in the driver  101 , the program is installed in the auxiliary storage  102  from the recording medium  107  via the driver  101 . However, the program does not necessarily have to be installed from the recording medium  107 , and may be downloaded from another computer via a network. The auxiliary storage  102  stores necessary information such as an installed program and a recipe. When there is a command to start the program, the memory  103  reads the program from the auxiliary storage  102  and stores the program. The CPU  104  executes a function related to the processing system  1  according to the program stored in the memory  103 . The interface  105  is used as an interface for connecting to a network. The display  106  displays various pieces of information and also functions as an operation device that accepts operations by an operator. 
     [Loader Module] 
     An example of a loader module  30  of an embodiment will be described with reference to  FIG. 3 .  FIG. 3  is a view illustrating an example of the loader module  30 . 
     The loader module  30  is, for example, an equipment front end module (EFEM) and forms a space having a higher degree of cleanliness than the environment in the factory in which the processing system  1  is provided. The space may be, for example, a mini-environment (Mini-E). The loader module  30  includes a first chamber  310 , a second chamber  320 , a circulation part  330 , a gas introduction part  340 , an exhaust part  350 , and a controller  390 . 
     The first chamber  310  is connected to an upper portion of the second chamber  320 . The pressure within the first chamber  310  is set to be lower than the pressure within the second chamber  320 . The first chamber  310  includes an inlet port  311 , a first pressure gauge  312 , and an airflow generator  313 . 
     The inlet port  311  is a port through which a replacement gas is introduced from the circulation part  330 , and the replacement gas is introduced into the first chamber  310  from the circulation part  330  through the inlet port  311 . In the present embodiment, the inlet port  311  is formed in one side wall of the first chamber  310 , but the inlet port  311 , for example, may be formed in each of two opposite side walls of the first chamber  310  or may be formed in the ceiling of the first chamber  310 . The replacement gas may be, for example, an inert gas, such as nitrogen (N 2 ) or argon (Ar), or clean dry air (CDA). 
     The first pressure gauge  312  measures the pressure within the first chamber  310  and transmits the measured value to the controller  390 . 
     The airflow generator  313  includes a circulation fan  314  and a filter  315 . The circulation fan  314  is provided within the first chamber  310 , and the replacement gas is sent from the inside of the first chamber  310  into the inside of the second chamber  320 . The filter  315  is provided below the circulation fan  314 , purifies the replacement gas sent by the circulation fan  314  by filtering the replacement gas, and supplies the purified replacement gas into the second chamber  320 . The filter  315  includes, for example, an ultra-low penetration air (ULPA) filter and a chemical filter. By driving the circulation fan  314 , the airflow generator  313  generates a downward flow of the purified gas from the first chamber  310  to the second chamber  320 . The airflow generator  313  may be a fan filter unit (FFU) in which the circulation fan  314  and the filter  315  are integrated. 
     The second chamber  320  is connected to the bottom side of the first chamber  310 , and the above-mentioned transporter  31  is disposed inside the second chamber  320 . The second chamber  320  includes a circulation port  321 , an exhaust port  322 , a second pressure gauge  323 , a thermometer  324 , a dew point meter  325 , and an oxygen concentration meter  326 . 
     The circulation port  321  is a port for causing the replacement gas to flow out from the inside of the second chamber  320  to the circulation line  331 , and the replacement gas flows out from the inside of the second chamber  320  to the circulation part  330  through the circulation port  321 . In the present embodiment, the circulation port  321  is formed in one side wall of the second chamber  320 , but the circulation port  321 , for example, may be formed in each of two opposite side walls of the second chamber  320 , and may be formed in the bottom portion. 
     The exhaust port  322  is a port for exhausting a gas from the inside of the second chamber  320  to the exterior, and the gas is exhausted from the inside of the second chamber  320  through the exhaust port  322 . In the present embodiment, the exhaust port  322  is formed in one side wall of the second chamber  320 , but the exhaust port  322 , for example, may be formed in each of two opposite side walls of the second chamber  320 , or may be formed in the bottom portion. In addition, the exhaust port  322 , for example, may be formed in the circulation line  331 . 
     The second pressure gauge  323 , the thermometer  324 , the dew point meter  325 , and the oxygen concentration meter  326  measure the pressure, temperature, dew point temperature, and oxygen concentration in the second chamber  320 , respectively, and transmit the measured values to the controller  390 . 
     The circulation part  330  circulates the replacement gas from the inside of the second chamber  320  to the inside of the first chamber  310 . The circulation part  330  includes a circulation line  331  and a circulation valve  332 . 
     One end of the circulation line  331  is connected to the inlet port  311  and the other end is connected to the circulation port  321  to allow an inside of the first chamber  310  and an inside of the second chamber  320  to communicate with each other such that the replacement gas is circulated from the inside of the second chamber  320  to the inside of the first chamber  310 . 
     The circulation valve  332  is provided to enable opening or closing of the circulation port  321  to control the communication state between the inside of the second chamber  320  and the inside of the circulation line  331 . When the circulation valve  332  is closed, the communication between the second chamber  320  and the circulation line  331  is cut off, and the circulation of the replacement gas from the second chamber  320  to the first chamber  310  is stopped. On the other hand, when the circulation valve  332  is opened, the inside of the second chamber  320  and the inside of the circulation line  331  communicate with each other, and the replacement gas circulates from the inside of the second chamber  320  to the inside of the first chamber  310 . In addition, the circulation valve  332  may be provided in the circulation line  331 . 
     The gas introduction part  340  introduces an inert gas and clean dry air, which are replacement gases, into the circulation line  331 . The gas introduction part  340  includes an inert gas source  341 , an inert gas supply pipe  342 , a valve  343 , a flow rate controller  344 , a CDA source  345 , a CDA supply pipe  346 , a flow rate adjusting valve  347 , and a valve  348 . 
     The inert gas source  341  supplies the inert gas into the circulation line  331  via the inert gas supply pipe  342 . The inert gas may be, for example, N 2  or Ar. The valve  343  is provided in the inert gas supply pipe  342  to open or close the flow path in the inert gas supply pipe  342 . The flow rate controller  344  is provided in the inert gas supply pipe  342  to control the flow rate of the inert gas flowing in the inert gas supply pipe  342 . The flow rate controller  344  may be, for example, a mass flow controller (MFC). 
     The CDA source  345  supplies clean dry air (CDA) into the circulation line  331  via the CDA supply pipe  346 . The flow rate adjusting valve  347  is provided in the CDA supply pipe  346  to adjust the flow rate of the clean dry air flowing in the CDA supply pipe  346 . The valve  348  is provided in the CDA supply pipe  346  to open or close the flow path in the CDA supply pipe  346 . 
     The gas introduction part  340  supplies at least one of the inert gas, the flow rate of which is controlled by the flow rate controller  344 , and the clean dry air, the flow rate of which is controlled by the flow rate adjusting valve  347 , into the circulation line  331 . 
     The exhaust part  350  exhausts the gas in the second chamber  320 . The exhaust part  350  includes an exhaust pipe  351  and an exhaust flow rate adjuster  352 . The exhaust pipe  351  is connected to the exhaust port  322  of the second chamber  320 . The exhaust flow rate adjuster  352  is provided in the exhaust pipe  351  to adjust the exhaust flow rate of the gas from the inside of the second chamber  320 . For example, the exhaust flow rate adjuster  352  includes two or more exhaust flow paths having different exhaust conductance, and is configured to adjust the exhaust flow rate by switching an exhaust flow path communicating with the exhaust pipe  351 . Further, the exhaust flow rate adjuster  352 , for example, may include an opening degree control valve and may be configured to adjust the exhaust flow rate by controlling the opening degree of the opening degree control valve. The exhaust part  350  evacuates the inside of the second chamber  320  through the exhaust pipe  351  by the exhaust flow rate adjuster  352  such that the inside of the second chamber  320  has a predetermined pressure. 
     The controller  390  controls at least one of the airflow generator  313 , the gas introduction part  340 , and the exhaust part  350  based on at least one measured value of the first pressure gauge  312 , the second pressure gauge  323 , the thermometer  324 , the dew point meter  325 , and the oxygen concentration meter  326 . 
     For example, when a wafer W is transported by the transporter  31 , the controller  390  operates the circulation fan  314  and opens the circulation valve  332  to circulate the replacement gas between the inside of the first chamber  310  and the inside of the second chamber  320  through the circulation line  331 . The controller  390  adjusts at least one of the gas introduction part  340  and the exhaust part  350  such that the inside of the first chamber  310  is in a positive pressure state. For example, the controller  390  adjusts the inside of the first chamber  310  to a positive pressure state by controlling the exhaust flow rate adjuster  352  of the exhaust part  350  to reduce the exhaust flow rate of evacuating the inside of the second chamber  320 . In addition, the controller  390 , for example, adjusts the inside of the first chamber  310  to a positive pressure state by opening the valve  348  of the gas introduction part  340  and increasing the opening degree of the flow rate adjusting valve  347  to increase the amount of clean dry air supplied into the first chamber  310  via the circulation line  331 . Further, the controller  390 , for example, adjusts the inside of the first chamber  310  to a positive pressure state by opening the valve  343  of the gas introduction part  340  by adjusting the flow rate controller  344  to increase the amount of the inert gas supplied to the inside of the first chamber  310  via the circulation line  331 . The controller  390  may perform these operations in combination. 
     Another example of the loader module  30  of the embodiment will be described with reference to  FIG. 4 . The loader module  30 A illustrated in  FIG. 4  is different from the loader module  30  illustrated in  FIG. 3  in that the gas introduction part  340  introduces the inert gas and the clean dry air as replacement gases into the first chamber  310 . The other configurations may be the same as those of the loader module  30  illustrated in  FIG. 3 . Hereinafter, a configuration different from that of the loader module  30  illustrated in  FIG. 3  will be mainly described. 
     The first chamber  310  includes a second inlet port  316  in addition to the configuration illustrated in  FIG. 3 . The second inlet port  316  is a port through which the replacement gas is introduced from the gas introduction part  340 , and the replacement gas is introduced from the gas introduction part  340  into the first chamber  310  via the second inlet port  316 . In the present embodiment, among the side walls of the first chamber  310 , the second inlet port  316  is formed in the same side wall as the side wall in which the inlet port  311  is formed, but the second inlet port  316 , for example, may be formed in a side wall different from the side wall in which the inlet port  311  is formed. For example, the second inlet port  316  may be formed in the ceiling. In addition, the second inlet ports  316 , for example, may be formed in multiple portions of the side walls and the ceiling of the first chamber  310 . 
     The gas introduction part  340  introduces the inert gas and clean dry air, which are replacement gases, into the first chamber  310 . The gas introduction part  340  includes an inert gas source  341 , an inert gas supply pipe  342 , a valve  343 , a flow rate controller  344 , a CDA source  345 , a CDA supply pipe  346 , a flow rate adjusting valve  347 , and a valve  348 . The gas introduction part  340  supplies at least one of the inert gas, the flow rate of which is controlled by the flow rate controller  344 , and the clean dry air, the flow rate of which is controlled by the flow rate adjusting valve  347 , into the first chamber  310 . 
     [Controlling Method] 
     An example of a controlling method of an embodiment will be described with reference to  FIGS. 5 to 7 .  FIG. 5  is a diagram illustrating an example of a controlling method of an embodiment.  FIG. 6  is a view illustrating an example of operations of a valve and a circulation fan in the controlling method of  FIG. 5 .  FIG. 7  is a view illustrating another example of operations of the valve and the circulation fan in the controlling method of  FIG. 5 . 
     The controlling method illustrated in  FIG. 5  is implemented, for example, when the loader module  30  is started or when the loader module  30  is returned after maintenance. In addition, the loader module  30  will be described assuming that at the start of the controlling method illustrated in  FIG. 5 , the inside of the second chamber  320  has an air atmosphere. 
     First, in step S 11 , the controller  390  operates the loader module  30  in a gas replacement mode. In the present embodiment, the controller  390  closes the circulation valve  332  and stops (turns off) the circulation fan  314 . In addition, the controller  390  opens the valve  343 , sets the flow rate of the flow rate controller  344  for setting to a maximum value (e.g., 1000 L/min), and controls the exhaust flow rate adjuster  352  to increase the exhaust flow rate. As a result, a large flow rate of an inert gas is introduced from the inert gas source  341  into the second chamber  320 , and the air in the second chamber  320  is pushed out by the large flow rate of the inert gas, so that the air is exhausted from the inside of the second chamber  320  at a high speed. As a result, the air atmosphere inside the second chamber  320  is replaced with the inert gas atmosphere in a short period of time. 
     Next, in step S 12 , the controller  390  determines whether or not humidity in the second chamber  320  is equal to or lower than a first value. In the present embodiment, the controller  390  calculates the humidity in the second chamber  320  based on the measured value of the thermometer  324  and the measured value of the dew point meter  325 , and determines whether or not the calculated humidity is equal to or lower than the first value. The first value is, for example, a value predetermined depending on a volume of the second chamber  320  or the like, and may be, for example, 50 ppm to 500 ppm. When it is determined in step S 12  that the humidity in the second chamber  320  is equal to or lower than the first value, the controller  390  advances the process to step S 13 . When it is determined in step S 12  that the humidity in the second chamber  320  is higher than the first value, the controller  390  returns the process to step S 11 . That is, the controller  390  operates the loader module  30  in the gas replacement mode until the humidity in the second chamber  320  becomes equal to or lower than the first value. 
     Next, in step S 13 , the controller  390  operates the loader module  30  in an airflow stirring mode. In the present embodiment, the controller  390  drives (turns on) the circulation fan  314  and opens the circulation valve  332  in a state in which the introduction of the inert gas into the second chamber  320  from the inert gas source  341  and evacuation of the inside of the second chamber  320  are continued. As a result, the airflow in the second chamber  320  is stirred, and the air (humidity), which remains in the corner inside the second chamber  320  and is difficult to be replaced in the gas replacement mode, is exhausted to the exterior of the second chamber  320 . In step S 13 , the controller  390  drives, for example, the circulation fan  314  at a low speed. 
     Next, in step S 14 , the controller  390  determines whether or not a predetermined period of time has elapsed since the loader module  30  was operated in the airflow stirring mode. The predetermined period of time is, for example, a length of time predetermined depending on the volume of the second chamber  320  or the like. When it is determined in step S 14  that a predetermined period of time has elapsed since the loader module  30  was operated in the air flow stirring mode, the controller  390  advances the process to step S 15 . When it is determined in step S 14  that a predetermined period of time has not elapsed since the loader module  30  was operated in the airflow stirring mode, the controller  390  returns the process to step S 13 . That is, the controller  390  operates the loader module  30  in the airflow stirring mode until the predetermined period of time elapses. 
     Next, in step S 15 , the controller  390  operates the loader module  30  in the gas replacement mode. In the present embodiment, the controller  390  closes the circulation valve  332  and stops the circulation fan  314  in a state in which the introduction of the inert gas into the second chamber  320  from the inert gas source  341  and evacuation of the inside of the second chamber  320  are continued. As a result, the air in the second chamber  320  is pushed out by the large flow rate of the inert gas introduced into the second chamber  320  from the inert gas source  341 , so that the air is exhausted from the inside of the second chamber at a high speed. As a result, the air atmosphere inside the second chamber  320  is replaced with the inert gas atmosphere in a short period of time. 
     Next, in step S 16 , the controller  390  determines whether or not the humidity in the second chamber  320  is equal to or lower than a second value. In the present embodiment, the controller  390  calculates the humidity in the second chamber  320  based on the measured value of the thermometer  324  and the measured value of the dew point meter  325 , and determines whether or not the calculated humidity is equal to or lower than the second value. The second value is predetermined depending on, for example, the volume of the second chamber  320  or the like, and is smaller than the first value. The second value may be, for example, 10 ppm to 200 ppm. When it is determined in step S 16  that the humidity in the second chamber  320  is equal to or lower than the second value, the controller  390  advances the process to step S 17 . When it is determined in step S 16  that the humidity in the second chamber  320  is higher than the second value, the controller  390  returns the process to step S 15 . That is, the controller  390  operates the loader module  30  in the gas replacement mode until the humidity in the second chamber  320  becomes equal to or lower than the second value. 
     Next, in step S 17 , the controller  390  operates the loader module  30  in a circulation transition mode. In the present embodiment, the controller  390  controls the exhaust flow rate adjuster  352  to reduce the exhaust flow rate and to reduce the flow rate of the flow rate controller  344  for setting. Further, the controller  390  drives the circulation fan  314  and opens the circulation valve  332 . As a result, the introduced amount of the inert gas is reduced, and the inert gas circulates between the inside of the first chamber  310  and the inside of the second chamber  320 . In step S 17 , as shown in  FIG. 6 , the controller  390  preferably increases a rotation speed of the circulation fan  314  in a stepwise manner from a low speed to a high speed. As a result, it is possible to suppress an increase in humidity at the time of transition from the gas replacement mode to the circulation mode. Further, as illustrated in  FIG. 7 , the controller  390  may continuously increase the rotation speed of the circulation fan  314  from a low speed to a high speed. 
     Next, in step S 18 , the controller  390  operates the loader module  30  in the circulation mode and then terminates the process. In the present embodiment, in the state in which the circulation valve  332  is opened and a small amount of the inert gas is introduced into the second chamber  320  from the inert gas source  341  so that the inside of the second chamber  320  is evacuated at a small exhaust flow rate, the controller  390  drives the circulation fan  314  at a predetermined speed (a low speed). Then, the controller  390  terminates the process in this state. In the state in which the loader module  30  is operating in the circulation mode, transport of a wafer W is performed within the second chamber  320  by the transporter  31 . 
     In step S 18 , in some embodiments, the controller  390  may adjust at least one of the gas introduction part  340  and the exhaust part  350  such that the inside of the first chamber  310  is in a positive pressure state. In the present embodiment, the controller  390  controls the exhaust flow rate adjuster  352  to reduce the exhaust flow rate for evacuating the inside of the second chamber  320 , opens the valve  343 , and adjusts the flow rate controller  344  to increase the amount of the inert gas supplied to the inside of the first chamber  310  through the circulation line  331 . As a result, the inside of the first chamber  310  is set to a positive pressure state. However, the controller  390  may set the inside of the first chamber  310  to a positive pressure state, for example, only by controlling the exhaust flow rate adjuster  352  to reduce the exhaust flow rate of evacuating the inside of the second chamber  320 . In addition, the controller  390  may set the inside of the first chamber  310  to a positive pressure state, for example, only by opening the valve  343  and adjusting the flow rate controller  344  to increase the amount of the inert gas supplied to the inside of the first chamber  310  through the circulation line  331 . In addition, the controller  390  may set the inside of the first chamber  310  to a positive pressure state, for example, only by opening the valve  348  and increasing the degree of opening of the flow rate adjusting valve  347  to increase the amount of the clean dry air supplied into the first chamber  310  through the circulation line  331 . Further, the controller  390  may set the inside of the first chamber to a positive pressure state by performing, for example, at least two or more of control of the exhaust flow rate adjuster  352 , opening or closing of the valve  343 , adjustment of the flow rate controller  344 , adjustment of the flow rate adjusting valve  347 , and opening or closing of the valve  348  in combination. 
     In this way, in step S 18 , the controller  390  adjusts at least one of the gas introduction part  340  and the exhaust part  350  such that the inside of the first chamber  310  is in a positive pressure state. As a result, it is possible to prevent air from being mixed into the inside of the first chamber  310  from the exterior of the loader module  30 . Therefore, even when the circulation fan  314  is driven in a state in which the replacement gas is circulated between the inside of the first chamber  310  and the inside of the second chamber  320  to send the replacement gas from the inside of the first chamber  310  into the inside of the second chamber  320 , it is possible to suppress the mixing of air into the inside of the second chamber  320 . As a result, it is possible to maintain a low humidity environment with low replacement gas consumption. 
     As described above, according to the controlling method of the embodiment, the controller  390  executes a step of evacuating the inside of the second chamber  320  at a high speed while introducing a large flow rate of an inert gas into the inside of second chamber  320  without circulating the replacement gas between the inside of the first chamber  310  and the inside of the second chamber  320 . As a result, the humidity in the second chamber  320  can be reduced in a short period of time. In other words, the time required to start the loader module  30  can be reduced. 
     According to the controlling method of the embodiment, the controller  390  controls the circulation fan  314  to be driven and the circulation valve  332  to be opened for a predetermined period of time between steps S 11  and S 15 , that is, while the loader module  30  is operating in the gas replacement mode. As a result, the airflow in the second chamber  320  is stirred, and the air (humidity), which remains in the corner inside the second chamber  320  and is difficult to be replaced in the gas replacement mode, is exhausted to the exterior of the second chamber  320 . As a result, the transition time from an air atmosphere to a low humidity environment can be reduced. 
     Further, according to the controlling method of the embodiment, when the operation of the loader module  30  transitions from the gas replacement mode to the circulation mode, the controller  390  operates the loader module  30  in the circulation transition mode. That is, when the operation of the loader module  30  transitions from the gas replacement mode to the circulation mode, the controller  390  increases the rotation speed of the circulation fan  314  from a low speed to a high speed. As a result, it is possible to suppress an increase in humidity when transitioning from the gas replacement mode to the circulation mode. 
     In the controlling method of the embodiment, a case of introducing, in step S 18 , a small flow rate of the inert gas from the inert gas source  341  into the second chamber  320  to evacuate the inside of the second chamber  320  with the small exhaust flow rate has been described, but the present disclosure is not limited thereto. For example, the controller  390  may close the valve  343  and control the exhaust flow rate adjuster  352  to stop the exhaust. However, in step S 18 , it is preferable to introduce a small flow rate of the inert gas from the inert gas source  341  into the second chamber  320  and to evacuate the inside of the second chamber  320  with a small exhaust flow rate. This makes it possible to maintain a low humidity environment even if water is mixed from the inside of the transport container  51  when the opening or closing door  37  that opens or closes the carry-in port  36  provided in the side surface of the loader module  30  is opened and a wafer W is transported to and from the transport container  51  placed on the load port  50 . 
     In the controlling method of the embodiment, a case of determining whether or not the humidity in the second chamber  320  is equal to or lower than the first value and equal to or lower than the second value in each of step S 12  and step S 16  has been described, but the object of the determination is not limited to humidity. For example, the object of determination may be oxygen concentration, or both humidity and oxygen concentration. 
     Another example of the controlling method of the embodiment will be described with reference to  FIG. 8 .  FIG. 8  is a diagram illustrating another example of the controlling method of the embodiment. 
     The controlling method illustrated in  FIG. 8  is different from the controlling method illustrated in  FIG. 7  in that, when the humidity in the second chamber  320  is higher than a third value after a predetermined period of time has elapsed since the loader module  30  was operated in the airflow stirring mode, the loader module  30  is operated in the airflow stirring mode. The other points may be the same as the controlling method illustrated in  FIG. 7 . 
     Step S 21  is performed when it is determined in step S 14  that a predetermined period of time has elapsed since the loader module  30  was operated in the air flow stirring mode. In step S 21 , the controller  390  determines whether or not the humidity in the second chamber  320  is equal to or lower than the third value. In the present embodiment, the controller  390  calculates the humidity in the second chamber  320  based on the measured value of the thermometer  324  and the measured value of the dew point meter  325 , and determines whether or not the calculated humidity is equal to or lower than the third value. The third value is, for example, a value predetermined depending on the volume of the second chamber  320  or the like, and may be the same as, for example, the first value. When it is determined in the step S 21  that the humidity in the second chamber  320  is equal to or lower than the third value, the controller  390  advances the process to step S 15 . When it is determined in step S 21  that the humidity in the second chamber  320  is higher than the third value, the controller  390  returns the process to step S 13 . That is, the controller  390  operates the loader module  30  in the airflow stirring mode until the humidity in the second chamber  320  becomes equal to or lower than the third value. 
     As described above, according to the controlling method of the embodiment illustrated in  FIG. 8 , the same operational effect as the controlling method of the embodiment illustrated in  FIG. 7  can be obtained. According to the controlling method of the embodiment illustrated in  FIG. 8 , by setting the predetermined period of time in step S 14  to be short, the time for operating the loader module  30  in the airflow stirring mode can be minimized, and thus the time required to start up the loader module  30  can be reduced. 
     In the controlling method of the embodiment illustrated in  FIG. 8 , a case of determining, in steps S 12 , S 16  and S 21 , whether or not the humidity in the second chamber  320  is equal to or lower than the first value, equal to or lower than the second value, and equal to or lower than the third value, respectively, has been described, but the object of determination is not limited to humidity. For example, the object of determination may be oxygen concentration, or both humidity and oxygen concentration. 
     According to the present disclosure, the transition time from an air atmosphere to a low humidity environment can be reduced. 
     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.