Patent Publication Number: US-2018040488-A1

Title: Substrate processing apparatus, recording medium, and fluid circulation mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2016-153823, filed on Aug. 4, 2016, and Japanese Patent Application No. 2017-116796, filed on Jun. 14, 2017, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a substrate processing apparatus, a recoding medium, and a fluid circulation mechanism. 
     BACKGROUND 
     In general, a vertical substrate processing apparatus has been used in a manufacturing process of a semiconductor. The vertical substrate processing apparatus may perform, in a transfer chamber (preparatory chamber) disposed on a lower side of a process chamber for processing wafers, the charging of unprocessed wafers to a substrate holder (boat) to be loaded into the process chamber (wafer charging) and the discharging of the processed wafers from the substrate holder unloaded from the interior of the process chamber (wafer discharging). In the transfer chamber, the high-temperature processed wafer unloaded from the process chamber is cooled to a predetermined temperature. In a related art, a cooling wall is provided in a preparatory chamber so as to surround a boat, and a coolant is circulated inside the cooling wall so as to cool the wafers. In another related art, a cooling wall and a cooling gas supply part provided at a position facing the cooling wall across a boat are provided in a preparatory chamber, and a cooling gas is supplied from the cooling gas supply part to the boat so as to cool the wafers. In a further related art, a clean unit for blowing the clean air into a transfer chamber and an exhaust unit disposed at a position facing the clean unit are provided so as to cool the wafers with an air flow formed by the clean unit and the exhaust unit. 
     SUMMARY 
     Some embodiments of the present disclosure provide a technique capable of shortening the time required for cooling a transfer chamber and substrates held by a boat. 
     According to one embodiment of the present disclosure, there is provided a configuration which includes a reaction furnace into which a substrate holder holding a plurality of substrates is loaded and unloaded from, a preparatory chamber provided below the reaction furnace, the substrate holder being disposed at a predetermined position in the preparatory chamber, an elevating mechanism configured to raise and lower the substrate holder between the reaction furnace and the preparatory chamber, a fluid circulation mechanism including a suction part configured to suck a fluid within the preparatory chamber, a pipe part constituting a flow path through which the fluid flows from the suction part to a supply part, and a cooling mechanism provided in the flow path and configured to cool the fluid, and a control part configured to control the fluid circulation mechanism and the elevating mechanism so as to lower the substrate holder from the reaction furnace to the predetermined position in the preparatory chamber, circulate the fluid sucked from the suction part through the flow path, and supply the fluid from the supply part to the preparatory chamber. The cooling mechanism is disposed adjacent to the suction part to cool the fluid introduced from the suction part with the cooling mechanism before circulating the fluid through the flow path. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an oblique perspective view of a substrate processing apparatus used in an embodiment of the present disclosure. 
         FIG. 2  is a schematic oblique perspective view of the interior of a substrate processing apparatus used in an embodiment of the present disclosure. 
         FIG. 3  is a schematic perspective view showing a fluid circulation mechanism of the transfer chamber shown in  FIG. 2 . 
         FIG. 4  is a schematic side view showing the fluid circulation mechanism shown in  FIG. 2 . 
         FIG. 5  is a schematic plan view showing an air flow in the transfer chamber shown in  FIG. 2 . 
         FIG. 6A  is a schematic view for explaining a structure of a cooling wall used in an embodiment of the present disclosure. 
         FIG. 6B  is a schematic view for explaining a structure of a cooling wall used in an embodiment of the present disclosure 
         FIG. 7  is a block diagram showing a schematic configuration of a controller of a substrate processing apparatus used in an embodiment of the present disclosure. 
         FIG. 8  is a schematic oblique perspective view of a substrate processing apparatus used in another embodiment of the present disclosure. 
         FIG. 9  is a schematic plan view showing an air flow in the transfer chamber shown in  FIG. 8 . 
         FIG. 10  is a schematic plan view of the interior of a transfer chamber of a substrate processing apparatus used in another embodiment of the present disclosure. 
         FIG. 11  is a schematic oblique perspective view of a transfer chamber door of a substrate processing apparatus used in another embodiment of the present disclosure. 
         FIG. 12  is a diagram for explaining the effect of the embodiment of the present disclosure. 
         FIG. 13  is a diagram for explaining the effect of the cooling wall of the embodiment of the present disclosure. 
         FIG. 14  is a view for explaining the effect of the cooling wall of the embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the Present Disclosure 
     Embodiments of the present disclosure will be now described in detail with reference to the drawings. Like or equivalent components, members, and processes illustrated in each drawing are given like reference numerals and a repeated description thereof will be properly omitted. Further, the embodiments are presented by way of example only, and are not intended to limit the present disclosure, and any feature or combination thereof described in the embodiments may not necessarily be essential to the present disclosure. 
     (1) Outline of Substrate Processing Apparatus 
     The substrate processing apparatus described in the present embodiment is used in a manufacturing process of a semiconductor device. The substrate processing apparatus processes substrates to be processed by heating the substrates with a heater in a state in which the substrates are accommodated in a process chamber. More specifically, the substrate processing apparatus is a vertical substrate processing apparatus that simultaneously processes a plurality of substrates stacked at predetermined intervals in the vertical direction. 
     Examples of the substrate to be processed by the substrate processing apparatus include a semiconductor wafer substrate (hereinafter simply referred to as “wafer”) in which a semiconductor device is built. Furthermore, examples of the process performed by the substrate processing apparatus include an oxidation process, a diffusion process, a reflow or annealing process for carrier activation and planarization after ion implantation, a film forming process by a thermal CVD (Chemical Vapor Deposition) reaction, and the like. 
     (2) Schematic Configuration of Substrate Processing Apparatus 
     Next, a schematic configuration example of a substrate processing apparatus preferably used in an embodiment of the present disclosure will be described. 
     (Apparatus as a Whole) 
     In the substrate processing apparatus  1 , the wafers  6  are accommodated in a cassette  2  as a substrate storage container and are loaded into or unloaded from the substrate processing apparatus  1 . The substrate processing apparatus  1  includes a housing  3 . On the front wall of the housing  3 , a cassette loading/unloading port  4  is provided so as to be opened and closed by a front shutter (not shown). Inside the housing  3 , a cassette stage  5  is provided adjacent to the cassette loading/unloading port  4 . 
     The cassette  2  is loaded onto the cassette stage  5  by an in-process transfer device (not shown) and is unloaded from the cassette stage  5 . The cassette stage  5  is arranged such that the wafers  6  in the cassette  2  are kept in a vertical posture by the in-process transfer device and the wafer gateway of the cassette  2  is oriented upward (in the + direction of the Z axis). The cassette stage  5  may be rotated so that the wafer gateway of the cassette  2  faces the rear side of the housing  3 . 
     Cassette shelves  7  are installed substantially at the center of the housing  3  in the front-rear direction (X-axis direction). The cassette shelves  7  are arranged in a plurality of stages and in a plurality of rows so that each of the cassette shelves  7  stores a plurality of cassettes  2 . The cassette shelves  7  are provided with a transfer shelf  9  which accommodates the cassette  2  to be transferred by a wafer transfer device  8 . A spare cassette shelf  11  is provided above the cassette stage  5  and is configured to preliminarily store the cassette  2 . 
     Between the cassette stage  5  and the cassette shelves  7 , a cassette transfer device  12  is installed. The cassette transfer device  12  is configured to transfer the cassette  2  between the cassette stage  5 , the cassette shelves  7  and the spare cassette shelf  11 . 
     A wafer transfer device  8  is installed on the rear side of the cassette shelves  7  (on the −direction side of the X axis). The wafer transfer device  8  includes a wafer transfer mechanism  8   a  capable of horizontally rotating or linearly moving the wafer  6 , an elevating mechanism  8   b  for moving the wafer transfer mechanism  8   a  up and down, and a tweezers  8   c  provided on the wafer transfer mechanism  8   a  and configured to pick up the wafer  6 . 
     On the rear side of the wafer transfer device  8 , a process furnace  14  as a reaction furnace for thermally treating the wafers  6  and a transfer chamber  15  as a preparatory chamber for temporarily accommodating the wafers  6  before and after the heat treatment are provided adjacent to each other in the vertical direction. In the transfer chamber  15 , a boat elevating (elevating mechanism)  16  is provided for raising and lowering a boat (substrate holder)  13  with respect to the process furnace  14 . The boat  13  is provided with a plurality of holding members and is configured to horizontally hold a plurality of wafers  6  (for example, about 50 to 150 wafers) aligned in the vertical direction with their centers aligned with each other. 
     The elevating mechanism  16  includes an elevating arm  17 . A seal cap  18  as a lid is horizontally provided on the elevating arm  17 . The seal cap  18  vertically supports the boat  13 . The seal cap  18  is configured to open and close the furnace opening portion of the process furnace  14 . 
     Above the cassette shelves  7 , a clean unit  19  is provided for supplying a clean air as a cleaned atmosphere. The clean unit  19  is configured to circulate the clean air inside the housing  3 . 
     (Transfer Chamber) 
     As shown in  FIGS. 2 to 5 , the substrate processing apparatus  1  includes a transfer chamber  15  in which a charging operation for causing unprocessed wafers  6  to be held in the boat  13  and a discharging operation for taking out processed wafers  6  from the boat  13  are performed. The transfer chamber  15  is formed in a quadrangular shape in a plan view by a ceiling wall  21   a , a floor  21   b , and side walls  21   c ,  21   d ,  21   e  and  21   f  surrounding four sides of the transfer chamber  15 . However, the shape of the transfer chamber  15  is not necessarily limited to the quadrangular shape in a plan view but may be a polygonal shape in a plan view (for example, a triangle shape in a plan view, a pentagonal shape in a plan view, or the like). Inside the ceiling wall  21   a , the floor  21   b  and the side walls  21   c ,  21   d ,  21   e  and  21   f , at least one reflection panel (transfer chamber panel), which are not shown, is provided. 
     In the side wall  21   d  on the front side (the + direction side of the X axis) of the transfer chamber  15 , a wafer loading/unloading port  22  as a substrate-container-side communication port is provided in order to transfer the wafers  6  between the wafer transfer device  8  and the boat  13  in the transfer chamber  15 . An opening  23  communicating with the interior of the process chamber  42  of the process furnace  14  is provided on the ceiling wall  21   a  of the transfer chamber  15  in such a shape and size that allows the boat  13  holding the wafers  6  to pass therethrough. A transfer chamber door (not shown) is provided in the side wall  21   f  on the rear side (the − direction side of the X axis) of the transfer chamber  15 . 
     In the transfer chamber  15 , a fluid circulation mechanism  25  and a cooling wall (cooling part)  27  are disposed in addition to the boat  13  and the elevating mechanism  16  for raising and lowering the boat  13 . The boat  13  is disposed closer to the side wall  21   f  on the more rear side than the center of the transfer chamber  15  and closer to the side wall  21   e  on the right side as viewed from the front side. The fluid circulation mechanism  25  sucks (e.g., removes), cools and cleans an atmosphere (air) as a fluid existing in the transfer chamber  15 , and supplies the same into the transfer chamber  15 . 
     (Fluid Circulation Mechanism) 
     The fluid circulation mechanism  25  includes a first duct  25   a  extending from the upper side to the lower side along the Z-axis direction, a second duct  25   b  extending on the floor along the Y-axis direction, a third duct  25   c  extending on the floor along the X-axis direction, and a fourth duct  25   d  extending on the floor along the Y axis direction. Each of the first duct  25   a , the second duct  25   b , the third duct  25   c  and the fourth duct  25   d  has a rectangular cross section. The first duct  25   a  is provided on the rear side (the − direction side of the X axis) of the transfer chamber  15 . For example, the first duct  25   a  is provided with a suction part  25   g  as a suction port at the uppermost part (upper end part) of the boat  13  (or the transfer chamber  15 ) and is configured to locally suck a high-temperature fluid in the transfer chamber  15 . Further, a suction part  25   h  as a suction port is arranged in the vicinity of the central portion (a middle portion in a vertical direction) of the boat  13  to prepare for the heat to release (or leak, flow, exchange) from the wafers  6 . The suction parts  25   g  and  25   h  are disposed in the vicinity of the wafers  6  mounted in the central portion) of the boat  13 . That is, by disposing the suction part  25   h  in a region where the heat releases from the processed wafers  6  is unlikely to occur, it is possible to reduce the temperature similarly to the wafers  6  mounted on the lower end portion of the boat  13 . As described above, in order to efficiently reduce the temperatures of the transfer chamber  15  and the wafers  6 , the suction parts  25   g  and  25   h  are disposed in a region of the transfer chamber  15  where the temperature becomes higher after boat loading or a region where the heat release from the wafer  6  is difficult to occur. The first duct  25   a  includes heat exchangers  25   i  and  25   j  as cooling mechanisms which are disposed adjacent to the downstream side of the suction parts  25   g  and  25   h  of the first duct  25   a  so as to immediately cool a gas as a kind of fluid entered from the suction parts  25   g  and  25   h . The first duct  25   a  is disposed in the vicinity of the side wall  21   e . The heat exchangers  25   i  and  25   j  are provided with pipes through which a coolant passes. As a high-temperature gas (for example, a high-temperature fluid introduced from the suction parts  25   g  and  25   h ) passes around the heat exchangers  25   i  and  25   j , the heat is transferred from the gas to the coolant. The heat is dissipated as the coolant (medium) is discharged to the outside of the transfer chamber  15  (substrate processing apparatus  1 ). By disposing the suction part  25   g  in the upper portion of the transfer chamber  15  and disposing the suction part  25   h  at a location such as the central portion of the wafer mounting region on the boat  13 , and by locally sucking the atmosphere from the suction parts  25   g  and  25   h , it is possible to quickly and efficiently send the high-temperature gas into the heat exchangers  25   i  and  25   j . The fourth duct  25   d  includes a circulation fan  25   k  installed therein. As described above, in the present embodiment, the fluid circulation mechanism  25  can efficiently cool the high-temperature gas because the suction parts  25   g  and  25   h  and the heat exchangers  25   i  and  25   j  are provided adjacent to each other. Furthermore, the fluid circulation mechanism  25  can cool the fluid introduced from the suction parts  25   g  and  25   h  by the heat exchangers  25   i  and  25   j  before circulating the fluid through the flow path. Since the fluid cooled by passing through the heat exchangers  25   i  and  25   j  circulates through the flow path, it is not possible for the fluid to hinder the temperature reduction of the atmosphere of the transfer chamber  15  due to the heat radiation. 
     The fluid circulation mechanism  25  further includes a fifth duct  25   e  connected to the fourth duct  25   d  and provided with a heat exchanger  251  as a cooling mechanism, and a sixth duct  25   f  connected to the fifth duct  25   e  and provided with a filter  25   m . The fifth duct  25   e  is disposed along the left side wall  21   c  as viewed from the front side in the transfer chamber  15 . The fifth duct  25   e  has a rectangular parallelepiped shape in which the side surface facing the side wall  21   c  is larger than the bottom surface, the top surface, the rear side surface and the front side surface. The heat exchanger  251  is provided with a pipe through which a coolant passes. Similar to the heat exchangers  25   i  and  25   j , the high-temperature gas (for example, the fluid introduced from the suction parts  25   g  and  25   h  and passed through the heat exchangers  25   i  and  25   j ) passes around the heat exchanger  251 . Thus, the heat is transferred from the gas to the coolant. The heat is dissipated as the coolant (medium) is discharged to the outside of the transfer chamber  15  (substrate processing apparatus  1 ). In this way, the fluid introduced from the suction parts  25   g  and  25   h  passes through the heat exchangers twice, whereby the more cooled fluid is circulated. The sixth duct  25   f  is disposed above the fifth duct  25   e  along the side wall  21   c  and is formed in a rectangular parallelepiped shape just like the fifth duct  25   e . The sixth duct  25   f  serving as a supply part includes a blowout port  25   n  for supplying a clean air passed through the filter  25   m  and functions as a clean unit for blowing out the clean air into the transfer chamber  15 . The first duct  25   a , the second duct  25   b , the third duct  25   c , the fourth duct  25   d , the fifth duct  25   e  and the sixth duct  25   f  are provided as pipe parts which constitute a flow path through which the fluid existing between the suction parts  25   g  and  25   h  and the sixth duct  25   f  flows. As used herein, the term “circulation duct” is a generic name of the first duct  25   a , the second duct  25   b , the third duct  25   c , the fourth duct  25   d , the fifth duct  25   e  and the sixth duct  25   f.    
     As shown in  FIGS. 4 and 5 , the air exhausted from the sixth duct  25   f  in the Y-axis direction passes between and around a plurality of wafers  6  mounted on the boat  13  and is sucked into the suction parts  25   g  and  25   h.    
     In the present embodiment, the transfer chamber  15  is not provided with a special air supply duct for supplying a cooling gas from the outside. The transfer chamber  15  is not cooled by the supply air (blow) using the air suction duct. The transfer chamber  15  is cooled by the suction of a high-temperature fluid. Accordingly, it is possible to suppress the swirling-up of the particles and the temperature bias (a state in which only a specific portion is not cooled and is heated to a high temperature) in the transfer chamber  15 . 
     In order to isolate the transfer chamber  15  from the outside, most of the atmosphere of the transfer chamber  15  circulates through the transfer chamber  15  via the fluid circulation mechanism  25 . Therefore, in order to maintain the temperature of the transfer chamber  15 , it is necessary to install a heat exchanger having a sufficient heat dissipation capability. Thus, in order to efficiently perform the heat exchange, as shown in  FIGS. 3 and 4 , the heat exchangers  25   i  and  25   j  are installed adjacent to the suction parts  25   g  and  25   h  of the first duct  25   a  on the downstream side of the suction parts  25   g  and  25   h  so as to immediately cool the fluid sucked by the suction parts  25   g  and  25   h , thereby reducing the heat which is accumulated in the apparatus from the surrounding members when the fluid passes through the circulation duct after the first duct  25   a . This eliminates the need for a heat exchanger of a very large size in the fifth duct  25   e . It is therefore possible to reduce the size of the heat exchanger  251 . Moreover, it is also possible not to include the heat exchanger  251 . 
     (Cooling Wall) 
     The cooling wall  27  is mainly used for the purpose of absorbing the radiant heat from the process chamber  42  (the interior of the process furnace  14 ). The cooling wall  27  is provided close to the side wall  21   f  on the rear side of the apparatus in the transfer chamber  15 . As shown in  FIGS. 6A and 6B , the cooling wall  27  is formed of a metal plate  27   x  made of a material having good heat conductivity, for example, aluminum. A flow path  27   y  through which a coolant (for example, water) flows is arranged in the metal plate  27   x . When the boat  13  is raised and lowered, the temperature rise of the transfer chamber panel due to the radiant heat from the interior of the process furnace  14  is reduced by installing the cooling wall  27 . This makes it possible to reduce the heat accumulated in the transfer chamber  15 . It is preferable that the surface of the metal plate  27   x  is made to have a surface color (for example, a black color) with a good heat absorption property by processing the surface of the metal plate  27   x  with black alumite or the like. By processing the surface of the cooling wall  27  with black alumite or the like, it is possible to improve the absorption efficiency of the radiant heat by the cooling wall  27 . This makes it possible to further improve the effect of shortening the cooling time of the wafers  6  and preventing the temperature rise inside the transfer chamber  15 . 
     In the present embodiment, by combining the fluid circulation mechanism  25  and the cooling wall  27 , it is possible to greatly reduce the temperature rise inside the transfer chamber  15  and to promote the heat dissipation from the wafers  6 . 
     Since the film formation time will be shortened and more strict control of an oxide film will be is required in the future, it is necessary to eliminate the heat accumulated in the apparatus a much as possible. 
     (Controller) 
     As shown in  FIG. 7 , the controller  121  as the control part (control means) is configured as a computer including a CPU (Central Processing Unit)  121   a , a RAM (Random Access Memory)  121   b , a memory device  121   c  and an I/O port  121   d . The RAM  121   b , the memory device  121   c  and the I/O port  121   d  are configured to exchange data with the CPU  121   a  via an internal bus  121   e . An input/output device  122  configured as, for example, a touch panel or the like is connected to the controller  121 . 
     The memory device  121   c  is composed of, for example, a flash memory, an HDD (Hard Disk Drive), or the like. A control program for controlling the operations of a substrate processing apparatus, a process recipe in which sequences and conditions of a substrate processing process such as a thin film forming process or the like to be described later are written, or the like is readably stored in the memory device  121   c . The process recipe functions as a program for causing the controller  121  to execute each sequence in a substrate processing process such as a thin film forming process or the like to be described later, so as to obtain a predetermined result. Hereinafter, the process recipe and the control program will be generally and simply referred to as “program.” 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  121   b  is configured as a memory area (work area) in which a program or data read by the CPU  121   a  is temporarily stored. 
     The I/O port  121   d  is connected to the MFC valve pressure sensor, the APC valve, the vacuum pump, the temperature sensor, the heater, the rotation mechanism, the elevating mechanism  16 , the fluid circulation mechanism  25 , and the like. 
     The CPU  121   a  reads the control program from the memory device  121   c  and executes the control program. The CPU  121   a  is configured to read the process recipe from the memory device  121   c  in response to the input of an operation command from the input/output device  122  or the like. The CPU  121   a  is configured to control, according to the contents of the process recipe thus read, the flow rate adjustment operation of various gases by the MFC, the opening/closing operation of the valves, the opening/closing operation of the APC valve, the pressure regulating operation by the APC valve based on the pressure sensor, the start and stop of the vacuum pump, the temperature adjustment operation of the heater based on the temperature sensor, the rotation and rotational speed adjustment operation of the boat  13  by the rotation mechanism, the elevating operation of the boat  13  by the elevating mechanism  16 , and the like. Furthermore, according to the present embodiment, the CPU  121   a  is configured to control the fluid circulation mechanism  25  so that after the boat  13  is lowered from the process furnace  14  to a predetermined position, the fluid in the transfer chamber  15  is sucked and delivered to the flow path from the suction parts  25   g  and  25   h  disposed in the vicinity of the boat  13 , the fluid is cooled by the heat exchangers  25   i  and  25   j  provided in the vicinity of the suction parts  25   g  and  25   h , and the cooled fluid is allow to flow through the flow path and is discharged from the sixth duct  25   f  to the transfer chamber  15 . The control of the cooling of the processed wafers  6  (or the adjustment of the temperature in the transfer chamber  15 ) is configured so as to be incorporated in the process recipe, but is not limited to the form incorporated in the process recipe. 
     The controller  121  is not limited to being configured as a dedicated computer but may be configured as a general-purpose computer. For example, the controller  121  according to the present disclosure may be configured by preparing an external memory device (for example, a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disk such as a CD or a DVD, a magneto-optical disk such as an MO, or a semiconductor memory such as a USB memory or a memory card)  123 , which stores the aforementioned program, and installing the program in a general-purpose computer using the external memory device  123 . Furthermore, the program may be supplied using a communication means such as the Internet or a dedicated line, instead of using the external memory device  123 . The memory device  121   c  or the external memory device  123  is configured as a non-transitory computer-readable recording medium. Hereinafter, the memory device  121   c  and the external memory device  123  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  121   c , a case of including only the external memory device  123 , or a case of including both the memory device  121   c  and the external memory device  123 . 
     (3) Substrate Processing Process 
     Next, a sequence example of a process of forming a film on a substrate (hereinafter also referred to as a film forming process) will be described as one of manufacturing processes of a semiconductor device using the substrate processing apparatus described above. Description will be made herein on an example in which a film is formed on the wafer  6  by alternately supplying a first process gas (precursor gas) and a second process gas (reaction gas) to the wafer  6  as a substrate. 
     Hereinafter, description will be made an example in which a silicon nitride film (Si 3 N 4  film) (hereinafter also referred to as SiN film) is formed on a substrate using a hexachlorodisilane (Si 2 Cl 6 , abbreviation: HCDS) gas as a precursor gas and using an ammonia (NH 3 ) gas as a reaction gas. In the following description, the operations of the respective parts constituting the substrate processing apparatus are controlled by the controller  121 . 
     In the film forming process of the present embodiment, a SiN film is formed on the wafer  6  by performing, a predetermined number of times (once or more), a cycle which non-simultaneously performs a step of supplying a HCDS gas to the wafer  6  in the process chamber  42 , a step of removing the HCDS gas (residual gas) from the process chamber, a step of supplying an NH 3  gas to the wafer  6  in the process chamber  42 , and a step of removing the NH 3  gas (residual gas) from the process chamber  42 . 
     The term “substrate” used herein is synonymous with the term “wafer.” 
     (Wafer Supply Step) 
     When processing the wafer  6  with the substrate processing apparatus  1 , first, the cassette  2  containing a plurality of wafers  6  is mounted on the cassette stage  5 . Then, the cassette  2  is transferred from the cassette stage  5  onto the cassette shelf  7  by the cassette transfer device  12 . 
     (Pre-Loading Transfer Step) 
     The wafer transfer mechanism  8   a  of the wafer transfer device  8  takes out the wafer  6  from the cassette  2 . Then, the unprocessed wafer  6  taken out from the cassette  2  is transferred to the boat  13  located in the transfer chamber  15 . That is, the wafer transfer device  8  performs a wafer charging operation of charging the unprocessed wafer  6  onto the boat  13  before the boat  13  is loaded into the process furnace  14 . As a result, the boat  13  holds the plurality of wafers  6  in a stacked state in which the wafers  6  are spaced apart from each other in the vertical direction. The number of wafers  6  held by the boat  13  and batch-processed is, for example, 25 to 100. This makes it possible to enhance the mass productivity. 
     (Loading Step) 
     After the wafer charging operation, the boat  13  holding a plurality of wafers  6  in an unprocessed state is loaded into the process furnace  14  by the elevating operation of the elevating mechanism  16  (boat loading). In other words, by operating the elevating mechanism  16 , the boat  13  holding the wafers  6  in an unprocessed state is loaded from the interior of the transfer chamber  15  into the process furnace  14 . At this time, the temperature rise of the transfer chamber panel due to the radiant heat from the interior of the process furnace  14  can be suppressed by the cooling wall  27 . This makes it possible to maintain the internal temperature of the transfer chamber  15  and to shorten the recovery time. 
     (Pressure Regulation and Temperature Adjustment) 
     Vacuum exhaust (reduced pressure exhaust) is performed so that the interior of the process furnace  14 , i.e., the space where the wafers  6  exists (hereinafter also referred to as process chamber) has a predetermined pressure (degree of vacuum). 
     In addition, the wafers  6  in the process chamber  42  are heated by the heater so that the wafers  6  have a predetermined temperature. At this time, the degree of power supply to the heater is feedback-controlled based on the temperature information detected by the temperature sensor so that the process chamber has a predetermined temperature distribution. The heating of the process chamber  42  by the heater is continued at least until the processing on the wafers  6  is completed. 
     Further, the rotation of the boat  13  and the wafers  6  by the rotation mechanism is started. As the boat  13  is rotated by the rotation mechanism, the wafers  6  are rotated. The rotation of the boat  13  and the wafers  6  by the rotation mechanism is continued at least until the processing on the wafers  6  is completed. 
     (Film Forming Process) 
     If the temperature of the process chamber is stabilized at a preset processing temperature, the following two steps, i.e., steps 1 and 2 are sequentially executed. 
     [Step 1] 
     In this step, an HCDS gas is supplied to the wafers  6  in the process chamber. 
     By supplying the HCDS gas to the wafers  6 , a silicon (Si)-containing layer as a first layer is formed on the outermost surface of the wafer  6 . 
     After the first layer is formed, the supply of the HCDS gas is stopped. At this time, the process chamber  42  is vacuum-exhausted by the vacuum pump so that the HCDS gas unreacted or contributed to the formation of the first layer, which remains in the process chamber  42 , is discharged from the process chamber  42 . At this time, the supply of an N 2  gas to the process chamber  42  is maintained. The N 2  gas acts as a purge gas, whereby the effect of discharging the gas remaining in the process chamber  42  from the process chamber  42  can be enhanced. 
     [Step 2] 
     After step 1 is finished, the NH 3  gas supplied to the wafer  6  reacts with at least a part of the first layer, i.e., the Si-containing layer formed on the wafer  6  in step 1. Thus, the first layer is thermally nitrided in a non-plasma manner and is changed (modified) to a second layer containing Si and N, i.e., a silicon nitride layer (SiN layer). After the second layer is formed, the supply of the NH 3  gas is stopped. Then, by the same processing procedure as in step 1, the NH 3  gas unreacted or contributed to the formation of the second layer and the reaction by-products, which remain in the process chamber, are discharged from the interior of the process chamber. 
     (Performing a Predetermined Number of Times) 
     A SiN film having a predetermined composition and a predetermined film thickness can be formed on the wafer  6  by performing, a predetermined number of times (n times), the cycle which non-simultaneously, i.e., asynchronously performs the two steps described above. Incidentally, it is preferable that the cycle described above is repeated a plurality of times. That is, it is preferable that the thickness of the second layer (SiN layer) formed when performing the above-described cycle once is set to be smaller than a predetermined film thickness, and the above-described cycle is repeated a plurality of times until the thickness of the SiN film formed by laminating the second layer (SiN layer) reaches a predetermined film thickness. 
     (Purging and Atmospheric Pressure Restoration) 
     After the film forming process is completed, the heating by the heater is stopped, and the temperature of the wafer  6  in the processed state is lowered to a predetermined temperature. Then, once the preset time elapses, an N 2  gas is supplied into the process chamber  42  and is exhausted from the exhaust pipe. The N 2  gas acts as a purge gas. As a result, the interior of the process chamber  42  is purged, and the gas and reaction by-products remaining in the process chamber  42  are removed from the process chamber  42  (purging). Thereafter, the atmosphere in the process chamber  42  is replaced with an inert gas (inert gas replacement), and the pressure in the process chamber  42  is restored to the atmospheric pressure (atmospheric pressure restoration). 
     (Unloading Process) 
     Thereafter, by the elevating operation of the elevating mechanism  16 , the seal cap  18  is lowered to open the lower end of the manifold, and the boat  13  holding the wafers  6  in the processed state is unloaded from the lower end of the manifold to the outside of the process chamber  42  (boat unloading). That is, the boat  13  holding the wafers  6  in the processed state is transferred from the process chamber  42  into the transfer chamber  15  by operating the elevating mechanism  16 . While the elevating mechanism  16  is moved down, the interior of the process chamber  42  and the transfer chamber  15  are not shielded. Therefore, the temperature rise of the panel of the transfer chamber  15  is suppressed by the cooling wall  27 , and the convection heat released from the boat  13  and the wafers  6  is efficiently dissipated to the outside of the apparatus by the heat exchangers  25   i  and  25   j  disposed in the vicinity of the suction parts  25   g  and  25   h  of the fluid circulation mechanism  25 . As a result, an unexpected uneven temperature distribution disappears and the highest temperature region in the transfer chamber  15  lies in the vicinity of the suction parts  25   g  and  25   h . Thus, by keeping the control member away from the suction parts  25   g  and  25   h  or by keeping the suction parts  25   g  and  25   h  away from the control member, it is possible to prevent the control member from being broken by heat. 
     Then, the boat  13  is allowed to wait at a predetermined position (a home position to be described later) until all the wafers  6  supported by the boat  13  are cooled down. In addition, while the boat  13  is being unloaded from the process chamber  42  by the elevating mechanism  16 , the valve (opening/closing valve) of the gas supply pipe may be opened to supply an N 2  gas (inert gas). 
     (Post-Loading Transfer Step) 
     After the wafers  6  of the boat  13  on standby are cooled down to a predetermined temperature (for example, a room temperature or so), the wafer transfer device  8  discharges the wafers  6  from the boat  13 . Then, the processed wafers  6  discharged from the boat  13  are transferred to and accommodated in the empty cassette  2  mounted on the cassette shelf  7 . That is, the wafer transfer device  8  performs a wafer discharging operation of taking out the processed wafers  6  held by the boat  13  from the boat  13  and transferring the processed wafers  6  to the cassette  2 . 
     Thereafter, the cassette  2  accommodating the processed wafers  6  is transferred from the cassette shelf  7  onto the cassette stage  5  by the cassette transfer device  12 . 
     In this way, a series of substrate processing processes performed by the substrate processing apparatus  1  according to the present embodiment are completed. 
     Other Embodiments of the Present Disclosure 
     Even if the shape of the fluid circulation mechanism is deformed, the same effect can be obtained by installing the heat exchangers near the suction ports. Even if the installation location or the shape of the cooling wall is changed, the same effect can be obtained. 
     The substrate processing apparatus shown in  FIG. 8  is the same as the substrate processing apparatus shown in  FIG. 2 , except for ducts  25   o  and  25   p  as take-in parts. As shown in  FIG. 8 , by attaching additional ducts  25   o  and  25   p  to the suction parts  25   g  and  25   h  and bringing take-in ports of the additional ducts  25   o  and  25   p  closer to the wafers  6 , it is possible to further promote the heat dissipation from the wafers  6  and to further improve the heat exchange efficiency. As shown in  FIG. 9 , the air flow is almost the same as in  FIG. 5 . There is almost no influence on the air flow. In the fluid circulation mechanism  25  shown in  FIGS. 8 and 9 , by bringing a take-in port close to the wafers  6 , it is possible to suck a gas having a higher temperature. By disposing the heat exchangers  25   i  and  25   j  immediately in the vicinity of the suction parts  25   g  and  25   h , it is possible to further improve the heat exchange efficiency. 
     As shown in  FIG. 10 , in order to increase the throughput, a so-called two-boat apparatus (boat changer)  29  for alternately loading or unloading two boats  13  into or from the process chamber is provided in the transfer chamber  15 . Even if the apparatus is provided with the boat changer  29 , it is possible to install the additional ducts  25   o  and  25   p  outside the boat movable range ROM and to avoid interference with the boat  13 . 
     As shown in  FIG. 11 , the transfer chamber  15  is provided with a transfer chamber door  30  on the rear side (the − direction side of the X axis) instead of the cooling wall  27 . Unlike the transfer chamber door of the substrate processing apparatus shown in  FIG. 3 , the transfer chamber door  30  includes a duct  31  extending from the transfer chamber  15  to the outside of the transfer chamber  15 , suction ports  32   a  and  32   b  extending from the transfer chamber  15 , heat exchangers  33   a  and  33   b  provided in the duct  31 , electric exhaust fans  34   a  and  34   b , and discharge ports  35   a  and  35   b.    
     As shown in  FIG. 11 , by adding the electric exhaust fans  34   a  and  34   b  to a portion which does not greatly affect the performance of the apparatus even if remodeling the transfer chamber door  30  or the like from the substrate processing apparatus shown in  FIG. 2 , it is possible to further promote the heat dissipation from the wafers  6  and to further improve the heat exchange efficiency. 
       FIG. 12  shows evaluation results obtained in a state in which 31 (thirty-one) wafers  6  are charged into the boat  13  in the form of the substrate processing apparatus shown in  FIG. 2 . The term “nearest radiator” refers to the heat exchangers  25   i  and  25   j  disposed in the vicinity of the suction parts  25   g  and  25   h . The term “water cooled plate” refers to the cooling wall  27 . The term “forced exhaust duct” means that a gas is exhausted to the outside of the transfer chamber  15  by the electric exhaust fans  34   a  and  34   b  of the transfer chamber door  30  shown in  FIG. 11 . The term “highest temperature in transfer chamber” refers to the instantaneously highest temperature in the transfer chamber  15 . The atmospheric temperature is measured at a fixed point where the temperature becomes highest. 
     No. 00 is the normal state (in which the heat exchangers  25   i  and  25   j  are removed from the fluid circulation mechanism  25 ). The time to reach 80 degrees C. (cooling time) is 11 minutes and 11 seconds. The highest temperature in the transfer chamber is 97.6 degrees C. 
     No. 01 is a case where the cooling wall  27  is added to the normal state of No. 00. The cooling time is shortened by 36 seconds from the normal state. The highest temperature in the transfer chamber is 5.3 degrees C. lower than in the normal state. 
     No. 03 is a case where the nearest radiator (the heat exchangers  25   i  and  25   j ) is added to the normal state of No. 00. The cooling time is shortened by 3 minutes and 3 seconds from the normal state. The highest temperature in the transfer chamber is 9.3 degrees C. lower than in the normal state. 
     No. 04 is a case where the cooling wall  27  and the nearest radiator (the heat exchangers  25   i  and  25   j ) are added to the normal state of No. 00. The cooling time is shortened by 2 minutes and 54 seconds from the normal state. The highest temperature in the transfer chamber is 23.9 degrees C. lower than in the normal state. It is more preferable to use a combination of the cooling plate and the nearest radiator rather than to use one of the cooling plate or the nearest radiator. 
     No. 02 is a case where the forced exhaust duct is added to the normal state of No. 00. The cooling time is shortened by half of that in the normal state, but the highest temperature in the transfer chamber is 11.1 degrees C. higher than in the normal state. However, the oxygen concentration in the transfer chamber is increased by 19.8%. By bringing the edges of the wafers  6  and the ducts (suction ports  32   a  and  32   b ) of the transfer chamber door  30  closer to 140 mm, the cooling time is halved. Therefore, it is effective to merely add the additional ducts  25   o  and  25   p  to the fluid circulation mechanism  25  as shown in  FIG. 8 . 
       FIG. 13  shows evaluation results obtained in a state in which 143 wafers  6  are charged into the boat  13  in the form of the substrate processing apparatus shown in  FIG. 2 .  FIG. 14  shows a change in the surface temperature of the cooling wall. 
     No. 00 is a normal state (in which the heat exchangers  25   i  and  25   j  are removed from the fluid circulation mechanism  25 ). The time to reach 80 degrees C. (cooling time) is 32 minutes and 43 seconds. The highest temperature in the transfer chamber is 129.4 degrees C. 
     No. 01 is a case where the cooling wall  27  is added to the normal state of No. 00. The cooling time is shortened by 2 minutes and 49 seconds from the normal state. The highest temperature in the transfer chamber is 5.3 degrees C. lower than in the normal state. 
     As shown in  FIG. 14 , during the period from “Unload” to “home” (the period in which the unloading of the boat  13  from the process furnace  14  (Unload) is started and the boat  13  is returned to the home position in the transfer chamber  15 ), the interior of the process furnace  14  and the transfer chamber  15  are in the same space. The reflective panel surface temperature RP increases at a maximum increasing rate of 60 degrees C./min. The cooling wall surface temperature CW also increases. This indicates that the reflection panel and the cooling wall  27  are receiving the radiant heat. 
     The boat  13  is returned to the home position as a predetermined position in the transfer chamber  15  and the interior of the process furnace  14  and the transfer chamber  15  are isolated from each other. Thus, the temperature rise is stopped. The reflection panel surface temperature RP is higher than the cooling wall surface temperature CW and the atmosphere temperature in the transfer chamber  15 . It is considered that after the interior of the process furnace  14  and the transfer chamber  15  are isolated, the reflection panel becomes a heat source that radiates heat. 
     Unlike the method in which the wafers  6  are cooled by blowing a cooling medium (air/N 2 ) onto the wafers  6  at a high blowing flow velocity of the cooling medium in order to increase the cooling rate, in the present embodiment, it is not necessary to increase the flow velocity of the cooling medium in order to perform cooling with the fluid circulation mechanism  25 . Thus, it is not possible for the particles around the wafers to swirl upward, the wafers  6  are vibrated to generate the particles, or the temperature distribution in the transfer chamber  15  is biased to damage the control parts. 
     In the present embodiment, the heat leakage due to the radiation to the transfer chamber  15  can be reduced by the cooling wall  27 . Therefore, even in the vertical apparatus in which a lot of time is taken to load (or unload) the wafers  6  into (or from) the interior of the process furnace  14  and in which the time during which the interior of the process furnace  14  and the transfer chamber  15  is in the same space becomes long, it is possible to reduce a bias in the temperature distribution in the transfer chamber  15 . 
     In the present embodiment, the heat exchangers  25   i  and  25   j  are provided in the vicinity of the suction ports (suction parts)  25   g  and  25   h . Therefore, heat moves to the duct itself (pipe) while the gas moves through the duct (flow path). It is possible to prevent the heat from diffusing into the transfer chamber  15  (including other members in the apparatus) until the gas passes through the heat exchangers  25   i  and  25   j.    
     According to the present embodiment, the air supply/exhaust ports are not provided near the wafers. Therefore, it is unlikely that the maintainability of the apparatus is deteriorated and the production capacity after the operation of the apparatus is lowered. That is, after processing the wafers  6 , the wafers  6  of the boat  13  can be quickly cooled down to a predetermined temperature (for example, about a room temperature). Thus, it is possible to immediately shift to the wafer discharging operation of taking out the processed wafers  6  from the boat  13  and transferring the processed wafers  6  from the boat  13  to the cassette  2 . 
     According to the present embodiment, heat can be efficiently dissipated to the outside of the apparatus. It is therefore possible to keep temperature of the transfer chamber  15  constant. Since the temperature of the transfer chamber  15  can be kept constant, it is possible to promote heat radiation from the wafers  6  and to shorten the cooling time. In addition, since the temperature of the transfer chamber  15  can be kept constant, it is possible to reduce the risk of a growth of a natural oxide film in the transfer chamber  15 . Moreover, since the risk of an occurrence of an unexpected bias in the temperature distribution of the transfer chamber  15  can be remarkably reduced, it is possible to prevent a breakage of the control member due to the heat. Furthermore, since the heat exchangers  25   i ,  25   j  and  25   l  are installed in the circulation ducts and the cooling wall  27  is installed in the transfer chamber door, it is possible to reduce the influence on the maintenance of the apparatus and the environment of the transfer chamber  15  (the air flow, the oxygen concentration, etc.). 
     The embodiments of the present disclosure have been specifically described above. However, the present disclosure is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present disclosure. 
     The present embodiment may be applied not only to a semiconductor manufacturing apparatus but also to an apparatus for processing a glass substrate such as an LCD device or the like. In the present embodiment, there has been described an example in which a film is deposited on a substrate. However, the present disclosure is not limited to such an embodiment. For example, the present disclosure may be suitably applied to a case of performing a process such as an oxidation process, a diffusion process, an annealing process or the like. 
     According to the present disclosure in some embodiments, it is possible to control the temperature of wafers and the temperature of an internal atmosphere of a 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.