Abstract:
With the miniaturization of semiconductors and the increase in the diameter of wafers, the wafer size increases. Therefore, a supply gas flow rate also increases as compared with a process of a conventional wafer size. Thus, it is difficult to perform an exhaust pressure control in the same manner as a conventional processing process. ON/OFF valves provided in a plurality of exhaust pipes communicating with a processing chamber and a vacuum pump, and a controller configured to control the ON/OFF valves are provided, and it is possible to cope with the increase in the diameter of the wafer by performing a valve on/off and pressure control operation in a process event.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a substrate processing apparatus, a method of manufacturing a semiconductor device, and a substrate processing method. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    With the miniaturization of semiconductors and the increase in the diameter of wafers, the volume of a semiconductor device housing has become large. Therefore, a supply gas flow rate increases as compared with a conventional processing process. Thus, it is difficult to perform an exhaust pressure control in the same manner as a conventional processing process. In order to avoid this, it is essential to increase an amount of exhaust. In order to increase the amount of exhaust, it is necessary to make an exhaust pipe thick and reduce conductance. A main valve is disposed near a reaction chamber so as to shorten a pipe as much as possible. However, if a valve or a pipe is simply made thick, a pipe is laid out in an outer side than a width of a substrate processing apparatus, thus increasing a footprint of the apparatus. 
         [0003]      FIG. 7  illustrates a conventional exhaust system. Pipes  704   a  and  704   b  are connected to a pump  703  through a main valve (pressure control valve: APC)  702  disposed at a position closest to a reaction chamber  701 . In a conventional processing process, a supply gas flow rate and a pressure control are possible in this system. However, due to an increase in a diameter of a wafer, a flow rate in a process of processing a semiconductor device is increased about 1.5 times as compared with a conventional processing process. Therefore, in order to perform a pressure control, it is necessary to increase a diameter of a pipe (see  FIG. 8 ). A layout of a conventional apparatus is illustrated in  FIG. 8 . A reaction chamber  701  and an APC  702  are connected through a pipe  704  and are laid out not to come out from a lateral width of the substrate processing apparatus. However, if the diameter of the pipe  704  or the APC  702  increases, the pipe  704  or the APC  702  is disposed to greatly come out from the lateral width of the substrate processing apparatus as illustrated in the layout of  FIG. 8 . Therefore, there is a problem that the footprint increases. 
       SUMMARY OF THE INVENTION 
     Technical Problem 
       [0004]    The present invention is directed to provide a substrate processing apparatus, a method of manufacturing a semiconductor device, and a substrate processing method, which solve a problem that it is difficult to perform the same exhaust pressure control as the conventional art when a supply gas flow rate is increased by an increase in a volume of a reaction tube due to an increase in a diameter of a substrate to be processed. 
       Solution to Problem 
       [0005]    In order to achieve the above object, a substrate processing apparatus according to the present invention is a substrate processing apparatus, including: a reaction tube configured to process substrates by carrying in a substrate holder holding a plurality of substrates; a gas supply unit configured to supply a processing gas into the reaction tube; an exhaust unit including at least two exhaust pipes configured to exhaust gas supplied by the gas supply unit, and valves provided in the at least two exhaust pipes to control exhaust amount of the at least two exhaust pipes; and a control unit configured to control the valves provided in the exhaust unit at a predetermined timing. 
         [0006]    Furthermore, a method of manufacturing a semiconductor device includes: carrying in a substrate holder holding a plurality of substrates into a reaction tube; supplying a processing gas from a gas supply unit into the reaction tube; after the process of supplying the processing gas, exhausting the processing gas by an exhaust unit, the exhaust unit including at least two exhaust pipes and at least two valves provided in the at least two exhaust pipes so as to control exhaust amount of the at least two exhaust pipes; and controlling the at least two valves provided in the exhaust unit at a predetermined timing. 
         [0007]    Furthermore, a substrate processing method includes: carrying in a substrate holder holding a plurality of substrates into a reaction tube; supplying a processing gas from a gas supply unit into the reaction tube; and after the process of supplying the processing gas, controlling at least two exhaust pipes and at least two valves so as to adjust exhaust amount of the exhaust pipes. 
       Advantageous Effects of Invention 
       [0008]    According to the present invention, it is possible to provide a substrate processing apparatus, a method of manufacturing a semiconductor device, and a substrate processing method, which are capable of performing an exhaust pressure control of a processing gas through a simple configuration in association with an increase in a diameter of a substrate to be processed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a substrate processing apparatus that is applied to the present invention. 
           [0010]      FIG. 2  is a side perspective view of the substrate processing apparatus that is applied to the present invention. 
           [0011]      FIG. 3  is a diagram illustrating a configuration of a controller of the substrate processing apparatus to which the present invention is applied. 
           [0012]      FIG. 4  is a schematic longitudinal sectional view of a substrate processing apparatus according to an embodiment of the present invention. 
           [0013]      FIG. 5  is a schematic horizontal sectional view of a substrate processing apparatus according to an embodiment of the present invention. 
           [0014]      FIG. 6  is a diagram illustrating an example of a process event according to an embodiment of the present invention. 
           [0015]      FIG. 7  is a schematic longitudinal sectional view of a substrate processing apparatus according to the related art. 
           [0016]      FIG. 8  is a schematic horizontal sectional view of a substrate processing apparatus, so as to describe the related art. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    First, a vertical heat treatment apparatus, which uses an example of the present invention, will be described with reference to  FIGS. 1 and 2 . A substrate processing apparatus of  FIGS. 1 and 2  is diagrams for describing a configuration of a semiconductor manufacturing apparatus that performs a processing process in a method of manufacturing a semiconductor device (IC). As a substrate processing apparatus, a case where a vertical heat treatment apparatus (hereinafter, simply referred to as a processing apparatus) performing oxidation, a diffusion process, a CVD process, or the like on a substrate is applied will be described below.  FIG. 1  is a perspective view of a processing apparatus that is applied to the present invention. Also,  FIG. 2  is a side perspective view of the processing apparatus illustrated in  FIG. 1 . 
         [0018]    As illustrated in  FIGS. 1 and 2 , the processing apparatus  101  of the present invention includes a housing  111  as a substrate processing apparatus body, which uses a FOUP (also called a cassette or a pod, and hereinafter referred to as a pod)  110  as a wafer carrier that accommodates a plurality of wafers (substrates)  200  made of silicon or the like and is used as a storage container. The wafers  200  are transferred in a state of being charged and sealed in the pod  110 . 
         [0019]    As a port disposed to be maintenance-possible, a front maintenance port  103  is disposed in a front anterior portion of a front wall  111   a  of the housing  111 . A front maintenance door  104  is provided so as to open and close the front maintenance port  103 . In the maintenance door  104 , a pod carrying-in/carrying-out port  112  is disposed to communicate with the inside and the outside of the housing  111 . The pod carrying-in/carrying-out port  112  is opened and closed by a front shutter  113 . In a front anterior side of the pod carrying-in/carrying-out port  112 , a load port  114  used as a carrying-in/carrying-out portion is provided. The load port  114  is configured such that the pod  110  is placed and aligned. The pod  110  is carried in to the load port  114  and is carried out from the load port  114  by an in-process transfer device (not illustrated). 
         [0020]    In an upper portion of a substantially central part of the housing  111  in a front-back direction, a pod shelf (housing shelf)  105  is provided. The pod shelf  105  is configured to store a plurality of pods  110  at multiple stages along multiple rows. The pod shelf  105  includes a support portion  116  which is vertically erected, and multi-stage placement portions  117  which are held to be independently movable in a vertical direction at each position of the upper, middle, and lower stages with respect to the support portion  116 . The pod shelf  105  is configured to hold a plurality of pods  110  in a state of being placed in the multi-stage placement portions  117 . That is, the pod shelf  105  accommodates a plurality of pods  110  at multiple stages in a vertical direction, for example, by placing two pods  110  to face the same direction on a straight line. 
         [0021]    A pod transfer device (accommodation container transfer mechanism)  118  is installed between the load port  114  and the pod shelf  105  in the housing  111 . The pod transfer device  118  includes a pod elevator  118   a  as an a shaft portion which is vertically movable while holding the pods  110 , and a pod transfer portion  118   b  as a transfer portion which transfers the pods  110  placed thereon in a horizontal direction. The pod transfer device  118  is configured to transfer the pods  110  among the load port  114 , the pod shelf  105 , and a pod opener  121  by a continuous operation of the pod elevator  118   a  and the pod transfer portion  118   b.    
         [0022]    In a lower portion of the substantially central part of the housing  111  in a front-back direction, a sub-housing  119  is built up over a rear end. A pair of wafer carrying-in/carrying-out ports  120  for carrying in and out the wafer  200  with respect to the sub-housing  119  is provided to be opened in a two-upper/lower-stage alignment in a vertical direction in a front wall  119   a  of the sub-housing  119 , and a pair of pod openers  121  and  121  is provided at two-upper/lower-stage wafer carrying-in/carrying-out ports  120  and  120 . The pod opener  121  includes placement tables  122  and  122  on which the pod  110  is placed, and cap attaching/detaching mechanisms  123  and  123  which attach and detach a cap of the pod  110  that is used as a sealing member. The pod opener  121  is configured to open and close a wafer loading/unloading port of the pod  110  by attaching and detaching the cap of the pod  110  placed on the placement table  122  by the cap attaching/detaching mechanism  123 . 
         [0023]    The sub-housing  119  constitutes a transfer chamber  124  that is fluidically isolated from an installation space of the pod transfer device  118  or the pod shelf  105 . In a front region of the transfer chamber  124 , a wafer transfer mechanism  125  is installed. The wafer transfer mechanism  125  includes a wafer transfer device  125   a  which can rotate or linearly move the wafer  200  in a horizontal direction, and a wafer transfer device elevator  125   b  which elevates the wafer transfer device  125   a . As schematically illustrated in  FIG. 1 , the wafer transfer device elevator (not illustrated) is installed between a right end portion of a pressure-resistant housing  111  and a right end portion of the front region of the transfer chamber  124  of the sub-housing  119 . Due to a continuous operation of the wafer transfer device elevator  125   b  and the wafer transfer device  125   a , tweezers (substrate holder)  125   c  of the wafer transfer device  125   a  are configured as a placement portion of the wafer  200  such that the wafer  200  is charged and discharged with respect to a boat (substrate holding tool)  217 . 
         [0024]    In a rear region of the transfer chamber  124 , a standby portion  126  is configured to accommodate the boat  217  and make the boat  217  stand by. Above the standby portion  126 , a processing furnace  202  used as a processing chamber is provided. A lower end portion of the processing furnace  202  is configured to be opened and closed by a furnace port shutter  147 . 
         [0025]    As schematically illustrated in  FIG. 1 , a boat elevator  115  for elevating the boat  217  is installed between the right end portion of the pressure-resistant housing  111  and the right end portion of the standby portion  126  of the sub-housing  119 . A seal cap  219  as a lid is configured to be horizontally mounted in an arm  128  as a connecting tool connected to an elevation table of the boat elevator  115 , and the seal cap  219  is configured to vertically support the boat  217  and close the lower end portion of the processing furnace  202 . 
         [0026]    The boat  217  includes a plurality of holding members and is configured to horizontally hold a plurality of wafers  200  (for examples, 50 to 125 wafers) in a state of being arranged in a vertical direction, with the centers of the wafers  200  being aligned. 
         [0027]    As schematically illustrated in  FIG. 1 , a clean unit  134  is provided in the left end portion being an opposite side of the boat elevator  115  side and the wafer transfer device elevator  125   b  side of the transfer chamber  124 . The clean unit  134  includes a supply fan and a dust-proof filter and supplies clean air  133  that is a cleaned atmosphere or inert gas. Although not illustrated, a notch alignment device is installed between the wafer transfer device  125   a  and the clean unit  134  as a substrate alignment device which aligns positions of the wafers in a circumferential direction. The clean air  133  blown from the clean unit  134  circulates through the notch alignment device  135 , the wafer transfer device  125   a , and the boat  217  of the standby portion  126 , is suctioned by a duct (not illustrated), and is exhausted to the outside of the housing  111 , or circulates to a primary side (supply side) being a suction side of the clean unit  134  and is blown into the transfer chamber  124  again by the clean unit  134 . 
         [0028]    Next, the operation of the substrate processing apparatus  100  will be described with reference to  FIGS. 1 to 3 . In the following description, the operations of the respective components constituting the substrate processing apparatus  100  are controlled by a controller  240 . The configuration of the controller  240  is illustrated in  FIG. 3 . The controller  240  controls the pod transfer device  118 , the pod shelf  105 , the wafer transfer mechanism  125 , the boat elevator  115 , and the like through an input/output device  241 . As illustrated in  FIGS. 1 and 2 , when the pod  110  is supplied to the load port  114 , the pod carrying-in/carrying-out port  112  is opened by the front shutter  113 , and the pod  110  on the load port  114  is carried in from the pod carrying-in/carrying-out port  112  to the inside of the housing  111  by the pod transfer device  118 . The carried-in pod  110  is automatically transferred and delivered to the designated placement portion  117  of the pod shelf  105  by the pod transfer device  118  and is temporarily stored. Then, the pod  110  is transferred and delivered from the pod shelf  105  to one pod opener  121  and is temporarily stored. Then, the pod  110  is transferred from the pod shelf  105  to one pod opener  121  and is delivered on the placement table  122 , or is directly transferred to the pod opener  121  and is delivered on the placement table  122 . At this time, the wafer carrying-in/carrying-out port  120  of the pod opener  121  is closed by the cap attaching/detaching mechanism  123 , and the clean air  133  is circulated and filled in the transfer chamber  124 . For example, the transfer chamber  124  is filled with a nitrogen gas as the clean air  133 , and an oxygen concentration is 20 ppm or less, which is much lower than an oxygen concentration of the inside of the housing  111  (ambient atmosphere). 
         [0029]    An opening-side end surface of the pod  110  placed on the placement table  122  is pressed against an opening edge portion of the wafer carrying-in/carrying-out port  120  in the front wall  119   a  of the sub-housing  119 , and the cap of the pod  110  is detached by the cap attaching/detaching mechanism  123  to open the wafer loading/unloading port. When the pod  110  is opened by the pod opener  121 , the wafer  200  is picked up from the pod  110  through the wafer loading/unloading port by the tweezers  125   c  of the wafer transfer device  125   a . After the wafer  200  is aligned by the notch alignment device  135 , the wafer is carried in to the standby portion  126  in the rear side of the transfer chamber  124  and is charged in the boat  217 . The wafer transfer device  125   a  which has delivered the wafer  200  to the boat  217  is returned to the pod  110  and charges a next wafer  200  in the boat  217 . 
         [0030]    During the operation of charging the wafer to the boat  217  by the wafer transfer mechanism  125  in one pod opener  121  (upper stage or lower stage), another pod  110  is transferred and delivered by the pod transfer device  118  from the pod shelf  105  to the other pod opener  121  (lower stage or upper stage). The operation of opening the pod  110  by the pod opener  121  is simultaneously performed. 
         [0031]    When a previously designated number of wafers  200  are charged into the boat  217 , the lower end portion of the processing furnace  202 , which has been closed by the furnace port shutter  147 , is opened by the furnace port shutter  147 . Subsequently, the boat  217  holding a group of the wafers  200  is carried in (loaded) to the inside of the processing furnace  202  when the seal cap  219  moves upward by the boat elevator  115 . 
         [0032]    After the loading, any processing is performed on the wafer  200  in the processing furnace  202 . After the processing, except for a wafer matching process in the notch alignment device  135  (not illustrated), the wafer  200  and the pod  110  are delivered in an order reverse to the above description. 
         [0033]    Next, an exhaust system according to the present invention will be described with reference to  FIGS. 4 to 6 .  FIG. 4  is a schematic longitudinal sectional view of the substrate processing apparatus according to the embodiment of the present invention, and  FIG. 5  is a schematic horizontal sectional view of the substrate processing apparatus according to the embodiment of the present invention. 
         [0034]    In the embodiment illustrated in  FIG. 4 , a film-forming gas or a doping gas, a processing gas such as an etching gas, a purge gas such as an inert gas, or a mixed gas thereof is supplied into the reaction tube  202  from a gas supply unit  401  passing through the reaction tube  202  (or a support member such as a manifold (not illustrated) which supports the reaction tube). In the embodiment of the present invention, an exhaust pipe is connected to the reaction tube  202  (or the support member such as a manifold (not illustrated) which supports the reaction tube), and the exhaust pipe is configured to become two systems in the same conductance (exhaust amount) at a downstream side of the connection portion with the reaction tube  202 . A variable valve (for example, APC valve or the like, and hereinafter described as APC valve being used)  303  which can control a valve opening degree so as to adjust the exhaust amount by the controller  240  is provided in one exhaust pipe. A fixed valve (hereinafter described as ON/OFF valve)  304  which can control only the ON/OFF switching is provided in parallel in the other exhaust pipe. In this way, the exhaust amount in the processing furnace  202  is controlled. In the embodiment of the present invention, the exhaust pipes which are divided into two systems are merged in the downstream and are connected to an exhaust pump  305 . As illustrated in  FIG. 5 , this configuration makes it possible to increase the exhaust amount without greatly increasing the footprint. 
         [0035]    Here, in the embodiment of the present invention, the exhaust system, that is, the exhaust line (exhaust part), is configured by the exhaust pipe, the APC valve  303 , the ON/OFF valve  304 , a pressure sensor (not illustrated), and the like. When necessary, the exhaust pump  305 , a trap device (not illustrated) or a damage prevention device (not illustrated) may be included in the exhaust system. 
         [0036]    Next, an exhaust control method performed using the substrate processing apparatus according to the embodiment of the present invention will be described in detail with reference to  FIG. 6 .  FIG. 6  is a diagram illustrating an example of a process event according to an embodiment of the present invention. 
         [0037]    In  FIG. 6 , a vertical direction represents a pressure inside the reaction tube, and a horizontal direction represents the elapse of time. In the embodiment of the present invention, a process of forming a film by using two types of processing gas with different processing pressures during a deposition process for depositing a desired film will be described. 
         [0038]    As described above, when the boat  217  carrying the wafer  200  is loaded into the processing furnace  202 , it is necessary to reduce a pressure from the atmospheric pressure to a desired pressure by evacuating the processing furnace  202 . At this time, when a large amount of exhaust is rapidly performed by fully opening the APC valve  303  and the ON/OFF valve  304  being the exhaust valves, a load may be applied to the valves or the exhaust pump  305  and each component may be damaged. Therefore, during a predetermined period, the controller  240  performs control such that the APC valve  303  is opened to a predetermined opening degree while the ON/OFF valve is closed. Due to such a control, the processing furnace is slowly exhausted (slow exhaust) (S 1 ). 
         [0039]    After the slow exhaust is performed for the previously determined time, or after the pressure is reduced to a desired slow exhaust pressure, the exhaust is performed at a maximum exhaust amount by opening the ON/OFF valve  304  while fully opening the valve opening degree of the APC valve  303  until a desired vacuum exhaust pressure is achieved (S 2 ). At this time, as illustrated in  FIG. 6 , the control may be performed such that when the pressure becomes the desired vacuum exhaust pressure, that pressure is maintained (S 2 ). 
         [0040]    When the processing furnace has the desired vacuum exhaust pressure, a furnace purge is performed by supplying an inert gas such as N 2  so as to clean the furnace (S 3 ). At this time, in order to maintain a furnace purge pressure, the pressure control is performed by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303  through the controller  240 . 
         [0041]    After the furnace purge is performed for the previously determined time, the purge gas is completely exhausted (S 4 ), and then, a processing gas A is supplied (S 5 ). In order to maintain the processing pressure P 1  during the supply of the processing gas A, the pressure control is performed by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303  through the controller  240 . At this time, as illustrated in  FIG. 6 , the control may be performed such that when the pressure becomes the desired vacuum exhaust pressure, that pressure is maintained (S 4 ). 
         [0042]    When the processing process using the processing gas A is completed, a processing process using a processing gas B is performed. 
         [0043]    After the supply of the processing gas A, in order to exhaust the processing gas A, the exhaust is performed at a maximum exhaust amount by opening the ON/OFF valve  304  while fully opening the valve opening degree of the APC valve  303  until a desired vacuum exhaust pressure is achieved (S 2 ′). 
         [0044]    When the processing furnace has a predetermined vacuum exhaust pressure, a furnace purge is performed by supplying an inert gas such as N 2  so as to clean the furnace (S 3 ′). At this time, in order to maintain a furnace purge pressure, the pressure control is performed by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303  through the controller  240 . 
         [0045]    After the furnace purge is performed for the previously determined time, the purge gas is completely exhausted (S 4 ′), and then, a processing gas B is supplied (S 5 ′). In order to maintain the processing pressure P 2  during the supply of the processing gas B, the pressure control is performed by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303  through the controller  240 . By performing these operations S 2  to S 5 ′ once or more, it is possible to form a film or a stacked film such as a laminated structure having a desired thickness. 
         [0046]    Hereinafter, the sequence of the present embodiment will be described in detail. Here, when assuming that the processing gas A is a titanium (Ti)-containing gas and the processing gas B is a nitrogen-containing gas, a processing process of forming a titanium nitride film (TiN film) by using these gas will be described as an example. 
         [0047]    As the titanium-containing gas, for example, titanium tetrachloride (TiCl 4 ) or tetrakis dimethyl amino titanium (Ti[N(CH 3 ) 2 ] 4 , abbreviation: TDMAT) may be used. As the nitrogen-containing gas, gas obtained by exciting an N 2  gas, an NF 3  gas, and an N 3 H 8  gas by plasma or heat as well as gas obtained by exciting an NH 3  gas by plasma or heat may be used. Gas obtained by diluting these gas with a rare gas such as argon (Ar), helium (He), neon (Ne), or xenon (Xe) gas may be excited by plasma or heat and used. 
         [0048]    When the plurality of wafers  200  is charged into the boat  217  (wafer charging), as illustrated in  FIG. 1 , the boat  217  supporting the plurality of wafers  200  is lifted by the boat elevator  115  and is loaded into the processing chamber (reaction chamber) of the reaction tube  202  (boat loading). In this state, the seal cap  219  is in a state of sealing the lower end portion of the reaction tube  202  through an O-ring  220 . 
         [0049]    The processing furnace is evacuated by the vacuum pump  305  such that the inside of the processing furnace has a desired pressure (vacuum degree). At this time, the pressure inside the processing furnace is measured by a pressure sensor (not illustrated). The processing furnace is slowly exhausted by a feedback control performed by the controller  240  such that the ON/OFF valve  304  is in an OFF state for a predetermined time and the APC valve  303  is opened to a predetermined opening degree, based on the measured pressure (S 2 ). 
         [0050]    When it is detected by the pressure sensor that the pressure inside the processing furnace is reduced to the desired pressure by the slow exhaust, the controller  240  controls the APC valve  303  and the ON/OFF valve  304  such that the opening degree of the APC valve  303  is fully opened to the maximum exhaust amount and the ON/OFF valve  304  is opened. 
         [0051]    (Furnace Purge Process S 3 ) 
         [0052]    When the processing furnace has the desired pressure (vacuum exhaust pressure), the furnace purge is performed by supplying an inert gas such as N 2  gas, which is a purge gas for cleaning the furnace (S 3 ). At this time, the controller  240  performs the pressure control by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303 , so that the pressure inside the furnace becomes the purge pressure. 
         [0053]    (Processing Gas A Supply Process S 5 ) 
         [0054]    After the furnace purge is performed for the previously determined time, the controller  240  stops supplying the inert gas and controls the opening degree of the APC valve  303  to completely exhaust the insert gas supplied to the processing furnace (S 4 ). After that, the titanium-containing gas, which is the processing gas A, is supplied (S 5 ). At this time, the inside of the processing chamber  201  is heated by a heater (not illustrated) to be a desired temperature. At this time, the energization state of the heater is feedback-controlled based on temperature information detected by a temperature sensor (not illustrated), such that the inside of the processing chamber  201  has a desired temperature distribution (temperature adjustment). The wafer  200  is rotated by the rotation of the boat  217  by a rotation mechanism (not illustrated) (wafer rotation). 
         [0055]    In the processing furnace  202 , the titanium-containing gas is supplied to the wafer  200  for a predetermined time. The controller  240  controls the APC valve  303  and the ON/OFF valve  304  such that the processing furnace  202  has a predetermined processing pressure P 1  (for example, the controller  240  performs control such that both of the APC valve  303  and the ON/OFF valve  304  are closed, or only the APC valve  303  is opened to a predetermined opening degree). By supplying the titanium-containing gas, the titanium-containing gas contacts the surface of the wafer  200  to form a titanium-containing layer as a “first element-containing layer” on the surface of the wafer  200 . The titanium-containing layer is formed to have a predetermined thickness and a predetermined distribution according to, for example, the pressure inside the processing furnace  202 , the flow rate of the titanium-containing gas, and the processing time in the processing furnace  202 . After the elapse of a predetermined time, the controller  240  stops supplying the titanium-containing gas. 
         [0056]    (Processing Gas A Exhaust Process S 2 ′) 
         [0057]    After the supply of the titanium-containing gas is stopped, the controller  240  performs control such that the titanium-containing gas existing within the processing furnace  202  is exhausted by fully opening the APC valve  303  and opening the ON/OFF valve  304 , and the processing furnace  202  has a desired pressure (vacuum exhaust pressure) (S 2 ′). 
         [0058]    (Furnace Purge Process S 3 ′) 
         [0059]    When the processing furnace has the desired pressure (vacuum exhaust pressure), the furnace purge is performed by supplying an inert gas such as N 2  gas, which is a purge gas for cleaning the furnace (S 3 ′). At this time, the controller  240  performs the pressure control by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303 , so that the pressure inside the furnace becomes the purge pressure. 
         [0060]    (Processing Gas B Supply Process S 5 ′) 
         [0061]    After the furnace purge is performed for the previously determined time, the controller  240  stops supplying the inert gas and controls the opening degree of the APC valve  303  to completely exhaust the insert gas supplied to the processing furnace (S 4 ′). After that, the nitrogen-containing gas, which is the processing gas B, is supplied (S 5 ′). 
         [0062]    In the processing furnace  202 , the nitrogen-containing gas excited by plasma or heat is supplied on the wafer  200  for a predetermined time. The titanium-containing layer already formed on the wafer  200  is modified by the excited nitrogen-containing gas, thereby forming a TiN layer containing the titanium element and the nitrogen element on the wafer  200 . 
         [0063]    The modified layer containing the titanium element and the nitrogen element is formed to have a predetermined thickness, a predetermined distribution, and a penetration depth of a predetermined nitrogen component with respect to the titanium-containing layer, for example, according to the pressure inside the processing furnace  202 , the flow rate of the excited nitrogen-containing gas, or the like. After the elapse of a predetermined time, the controller  240  stops supplying the nitrogen-containing gas. 
         [0064]    (Processing Gas B Exhaust Process) 
         [0065]    After the supply of the nitrogen-containing gas is stopped, the controller  240  performs control such that the nitrogen-containing gas existing within the processing furnace  202  is exhausted by fully opening the APC valve  303  and opening the ON/OFF valve  304 , and the processing furnace  202  has a desired pressure (vacuum exhaust pressure). 
         [0066]    By performing these operations S 2  to S 5 ′ once or more, it is possible to form a TiN film having a desired thickness. 
         [0067]    As described above, according to the present invention, since it is unnecessary to increase the diameter of the exhaust pipe or increase the size of the exhaust valve, it is possible to achieve the effect that can perform the same pressure control as the related art while suppressing an increase in the footprint. 
         [0068]    In addition, as described above, the embodiment of the present invention has been specifically described, but the present invention is not limited to the above-described embodiment. Various modifications can be made without departing from the scope of the present invention and the effects can also be achieved according to the modifications. 
         [0069]    For example, in the above-described embodiment of the present invention, in the furnace purge processes S 3  and S 3 ′ and the processing gas A and processing gas B supply processes S 5  and S 5 ′, the pressure inside the furnace is controlled by closing the ON/OFF valve  304  and controlling the opening degree of the APC valve  303 , but the present invention is not limited thereto. The control may be performed to maintain the pressure inside the furnace by closing both the APC valve  303  and the ON/OFF valve  304 . In addition, when the control of the pressure inside the furnace, for a cleaning process or the like other than above-described processes, is required, the pressure control may be performed using the APC valve  303 . Furthermore, when an exhaust, in which the control of the pressure inside the furnace is unnecessary, for a vacuum exhaust process or the like other than the above-described processes, is required, the ON/OFF valve  304  may be used. 
         [0070]    In addition, in the above-described embodiment of the present invention, it has been described that one of at least two valves provided in the exhaust pipe is the APC valve, and the other valve is the valve that can control only the ON-OFF switching, but the present invention is not limited thereto. Both valves may use the APC valves that can control the valve opening degree. Furthermore, the type of the valve is not limited to the APC valve. Any variable valve may be used as long as the valve opening degree of the valve can be controlled by the controller and the valve can change the conductance. 
         [0071]    In addition, in the above-described embodiment of the present invention, it has been described that the exhaust amount when the opening degree of the APC valve is maximum and the exhaust amount when the ON-OFF valve is opened are provided to be equal to each other, but the present invention is not limited thereto. The exhaust amount when the opening degree of the APC valve is maximum and the exhaust amount when the ON-OFF valve is opened may be different from each other. For example, the exhaust amount when the ON-OFF valve is opened may be larger than the exhaust amount when the opening degree of the APC valve is maximum. The exhaust amount when the ON-OFF valve is opened may be smaller than the exhaust amount when the opening degree of the APC valve is maximum. 
         [0072]    In addition, in the above-described embodiment of the present invention, the process of forming the titanium nitride film (TiN film) by using the titanium (Ti)-containing gas as the processing gas A and the nitrogen-containing gas as the processing gas B. However, a silicon nitride film (SiN film) may be formed by using silicon (Si)-containing gas as the processing gas A and a nitrogen-containing gas as the processing gas B. A silicon oxide film (SiO film) may be formed by using silicon-containing gas as the processing gas A and an oxygen-containing gas as the processing gas B. An aluminum nitride film (AlN film) may be formed by using aluminum (Al)-containing gas as the processing gas A and a nitrogen-containing gas as the processing gas B. An aluminum oxide film (AlO film) may be formed by using aluminum (Al)-containing gas as the processing gas A and an oxygen-containing gas as the processing gas B. In this case, as the silicon-containing gas, for example, organic raw materials, such as aminosilane-based tetrakis dimethyl amino silane (Si(N(CH 3 ) 2 )) 4 , abbreviation: 4DMAS) gas, trisdimethylaminosilane (Si(N(CH 3 ) 2 )) 3 H, abbreviation: 3DMAS) gas, bis diethylaminosilane (Si(N(C 2 H 5 ) 2 ) 2 H 2 , abbreviation: 2DEAS) gas, bis-tertiary-butyl-amino-silane (SiH 2 (NH(C 4 H 9 )) 2 , abbreviation: BTBAS) gas, as well as inorganic raw materials, such as dichlorosilane (SiH 2 Cl 2 , abbreviation: DCS) gas, tetrachlorosilane (SiCl 4 , abbreviation: TCS) gas, hexachlorodisilane (Si 2 Cl 6 , abbreviation: HCD) gas, and monosilane (SiH 4 ) gas can be used. As the oxygen-containing gas, for example, oxygen (O 2 ) gas, ozone (O 3 ) gas, nitric oxide (NO) gas, nitrous oxide (N 2 O) gas, and water vapor (H 2 O) can be used. As the aluminum-containing gas, for example, trimethylaluminum (Al(CH 3 ) 3 , abbreviated: TMA) can be used. 
         [0073]    In addition, in the above-described embodiment of the present invention, the processing process using the processing gas A and the processing gas B has been described, but the present invention is not limited thereto. The processing processes S 2  to S 5  using only the processing gas A may be repeatedly performed. 
         [0074]    As the substrate processing apparatus  101 , the semiconductor manufacturing apparatus is configured to perform the method of manufacturing the semiconductor device (IC), but the present invention can also be applied to an apparatus for processing a glass substrate, such as an LCD device, as well as the semiconductor manufacturing apparatus. 
         [0075]    Examples of the film-forming process performed by the substrate processing apparatus  101  include a CVD, a PVD, an ALD, an Epi, a process of forming an oxide film or a nitride film, and a process of forming a metal-containing film. Furthermore, the film-forming process may include an annealing processing, an oxidation process, a diffusion process, and the like. 
         [0076]    In addition, in the present embodiment, the substrate processing apparatus is described as the vertical processing apparatus  101 , but the present invention can be equally applied to a single-wafer type device. Furthermore, the present invention can be equally applied to an etching apparatus, an exposure apparatus, a lithography apparatus, a deposition apparatus, a molding apparatus, a development apparatus, a dicing apparatus, a wire bonding apparatus, an inspection apparatus, and the like. 
         [0077]    &lt;Preferred Aspects of Present Invention&gt; 
         [0078]    Hereinafter, preferred aspects of the present invention will be additionally described. 
         [0079]    (Supplementary Note 1) 
         [0080]    A substrate processing apparatus including: a reaction tube configured to process substrates by carrying in a substrate holder holding a plurality of substrates; a gas supply unit configured to supply a processing gas into the reaction tube; an exhaust unit including at least two exhaust pipes configured to exhaust gas supplied by the gas supply unit, and valves provided in the at least two exhaust pipes to control exhaust amount of the at least two exhaust pipes; and a control unit configured to control the valves provided in the exhaust unit at a predetermined timing. 
         [0081]    (Supplementary Note 2) 
         [0082]    The substrate processing apparatus as described in Supplementary Note 1, in which the valves include at least one variable valve configured to adjust exhaust amount according to the control of the control unit. 
         [0083]    (Supplementary Note 3) 
         [0084]    The substrate processing apparatus as described in Supplementary Note 2, in which the control unit adjusts the pressure inside the reaction tube to a second pressure by controlling the at least one variable valve and closing the other valves until the pressure inside the reaction tube changes from an atmospheric pressure to a first pressure and opening all of the other closed valves and the variable valves when the pressure inside the reaction tube reaches the first pressure; adjusts the pressure inside the reaction tube to a third pressure by controlling the at least one variable valve and closing the other valves during the process of cleaning the reaction tube; adjusts the pressure inside the reaction tube to the second pressure by opening all of the at least one variable valve and the other valves after the cleaning process; and controls the gas supply unit to supply the processing gas to the reaction tube after the pressure inside the reaction tube reaches the second pressure. 
         [0085]    (Supplementary Note 4) 
         [0086]    A method of manufacturing a semiconductor device including: carrying in a substrate holder holding a substrate into a reaction tube; supplying a processing gas from a gas supply unit into the reaction tube; after the process of supplying the processing gas, exhausting the processing gas by an exhaust unit, the exhaust unit including at least two exhaust pipes and at least two valves provided in the at least two exhaust pipes so as to control exhaust amount of the at least two exhaust pipes; and controlling the at least two valves provided in the exhaust unit at a predetermined timing. 
         [0087]    (Supplementary Note 5) 
         [0088]    A method of manufacturing a semiconductor device including: carrying in a substrate holder holding a of substrate into a reaction tube; at least two exhaust pipes connected to the reaction tube to exhaust an atmosphere in the reaction tube and valves connected to the exhaust pipe, at least one of which is a variable valve capable of changing an exhaust amount being provided, exhausting the reaction tube from an atmospheric pressure to a first pressure by controlling the variable valve; after the pressure inside the reaction tube is exhausted from the atmospheric pressure to the first pressure, exhausting the reaction tube to a second pressure by opening all of the variable valve and the other valves; after the process of exhausting to the second pressure, purging the inside of the reaction tube by supplying a purge gas by a gas supply unit provided in the reaction tube; after the supply of the purge gas, exhausting the reaction tube again to the second pressure by opening all of the variable valve and the other valves; and after the pressure inside the reaction tube reaches the second pressure again, forming a desired film by supplying the processing gas by the gas supply unit. 
         [0089]    (Supplementary Note 6) 
         [0090]    The substrate processing method including: carrying in a substrate holder holding a substrate into a reaction tube; supplying a processing gas from a gas supply unit into the reaction tube; and after the process of supplying the processing gas, controlling at least two exhaust pipes and at least two valves for adjusting exhaust amount of the exhaust pipes at a predetermined timing. 
         [0091]    (Supplementary Note 7) 
         [0092]    A substrate processing method including: carrying in a substrate holder holding a substrate into a reaction tube; supplying a processing gas from a gas supply unit into the reaction tube; at least two exhaust pipes connected to the reaction tube to exhaust an atmosphere in the reaction tube and valves connected to the exhaust pipe, at least one of which is a variable valve capable of changing an exhaust amount being provided, exhausting the reaction tube from an atmospheric pressure to a first pressure by controlling the variable valve; after the pressure inside the reaction tube is exhausted from the atmospheric pressure to the first pressure, exhausting the reaction tube to a second pressure by opening all of the variable valve and the other valves; after the process of exhausting to the second pressure, purging the reaction tube by supplying a purge gas by a gas supply unit provided in the reaction tube; after the supply of the purge gas, exhausting the reaction tube again to the second pressure by opening all of the variable valve and the other valves; and after the pressure inside the reaction tube reaches the second pressure again, forming a desired film by supplying the processing gas by the gas supply unit. 
       INDUSTRIAL APPLICABILITY 
       [0093]    As described above, the present invention can be used in a substrate processing apparatus, a method of manufacturing a semiconductor device, and a substrate processing method, which are capable of performing an exhaust pressure control of processing gas in association with an increase in the diameter of a substrate to be processed by a simple configuration. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           101  substrate processing apparatus 
           110  pod 
           124  transfer chamber 
           200  wafer (substrate) 
           202  reaction tube 
           217  boat 
           240  controller 
           303  APC valve (variable valve) 
           304  valve (ON/OFF valve) 
           401  gas supply unit