Patent Publication Number: US-2002012581-A1

Title: Substrate processing apparatus and method for manufacturing a semiconductor device

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to a substrate processing apparatus and method for manufacturing a semiconductor device; and, more particularly, to a substrate processing apparatus and method effectively capable of performing a heat treatment process, e.g., an annealing process, an oxygen film formation process, a diffusion process, and/or a film formation process, on a semiconductor wafer or a substrate into which a semiconductor integrated circuit having a semiconductor unit is inserted.  
       BACKGROUND OF THE INVENTION  
       [0002] A batch of vertically arranged hot-wall type heat treatment apparatus has generally been used for performing the heat treatment such as annealing process, oxide film formation process, diffusion process and/or film formation process, on a wafer in accordance with a known method for manufacturing a semiconductor device.  
       [0003] Japanese Patent No. 2681055 discloses a conventional heat treatment apparatus operated as described above. In the heat treatment apparatus, a boat replacement apparatus is located between a substrate transfer device and the space under the process tube and a set of, i.e., two, boats are mounted on the rotation table of the boat replacement apparatus. If a set of boats is rotated by 180 degrees based on the rotation table, an unprocessed boat may be replaced with a completely processed boat. In other words, while one boat (a first boat) holding a plurality of wafers is processed in the processing room of the process tube, the other boat (a second boat) with a new wafer mounted thereon is conveyed by the substrate transfer device.  
       [0004] Since, however, in the heat treatment apparatus in which at least two boats are used, there may be inevitable differences between the two boats after an etching process and a cleaning process, the procedure for conveying the wafers to the boats by using the substrate transfer device results in an error at the conveying procedure.  
       SUMMARY OF THE INVENTION  
       [0005] It is, therefore, an object of the present invention to provide a substrate processing apparatus and method for manufacturing a semiconductor device capable of preventing errors in the conveying procedure due to differences between two boats.  
       [0006] It is another object of the present invention to provide a substrate processing apparatus and method for manufacturing a semiconductor device capable of identifying the location of each boat.  
       [0007] In accordance with a preferred embodiment of the present invention, there is provided a substrate processing apparatus comprising:  
       [0008] a process tube for providing a process room therein;  
       [0009] at least two boats for taking a plurality of substrates in and out of the process tube;  
       [0010] a substrate transfer device for transferring the plurality of substrates to and from each of said at least two boats outside of the process tube; and  
       [0011] a boat identification device for identifying each boat at a transferring location thereof to generate an identification signal, wherein the identification signal represents a type of said each boat and the plurality of substrates are transferred to the transferring location of said each boat by the substrate transfer device. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0012] The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:  
     [0013]FIG. 1 represents a horizontal cross-sectional view for illustrating a chemical vapor deposition (CVD) apparatus in accordance with an embodiment of the present invention;  
     [0014]FIG. 2 shows a perspective view of the CVD apparatus shown in FIG. 1;  
     [0015]FIG. 3 describes a perspective view for illustrating a completely processed boat under cooling process;  
     [0016]FIG. 4 provides a horizontal cross-sectional view of the CVD shown in FIG. 3;  
     [0017]FIG. 5 presents a vertical cross-sectional view for illustrating the heat treatment stage under processing;  
     [0018]FIG. 6 explains a vertical cross-sectional view for illustrating the heat treatment stage after boats are taken out;  
     [0019]FIG. 7 sets forth a perspective view for illustrating a boat conveying apparatus;  
     [0020]FIG. 8 describes a perspective view for illustrating a clean unit;  
     [0021]FIGS. 9A and 9B provide a side view for illustrating a substrate transfer device with itself curtailed and extended, respectively;  
     [0022]FIG. 10 represents a block diagram for illustrating a control system;  
     [0023]FIGS. 11A to  11 E present boat identification means, wherein FIG. 11A is a plan view of a waiting stage; FIG. 11B is a front cross-sectional view which is cut off along the b-b line; FIG. 11C is a cross-sectional view which is cut off along the c-c line; FIG. 11D is a bottom view of the base of a boat; and FIG. 11E a cross-sectional view which is cut off along the e-e line;  
     [0024]FIGS. 12A and 12B are diagrams for illustrating the operations of the boat identification means, wherein FIG. 12A is a cutaway front view; FIG. 12B is a horizontal view which is cut off along the b-b line; FIG. 12C is a cross-sectional view which is cut off along the c-c line; and FIG. 12D is a cross-sectional view which is cut off along the d-d line. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0025] In a preferred embodiment in accordance with the present invention, a substrate processing apparatus comprises a batch of vertically arranged hot-wall type diffusion CVD apparatus (hereinafter called as a CVD apparatus). In another preferred embodiment in accordance with the present invention, a substrate processing method for manufacturing a semiconductor device comprises a diffusion and CVD method (hereinafter called as a CVD method) used to perform on a wafer a diffusion and CVD process such as an annealing process, an oxide film formation process, a diffusion process and a film formation process.  
     [0026] As shown in FIG. 1, the CVD apparatus  1  by which the CVD method may be performed in accordance with the present invention includes a housing body  2  having a box shape of rectangular parallelepiped with rectangle planes thereon. There is installed a clean unit  3  at the rear of the left sidewall (the left/right and the front/rear is determined based on FIG. 1), wherein the clean unit  3  is used to provide a clean air into the housing body  2 . There is installed a heat treatment stage  4  around the central region of the rear within the housing body  2  and there are installed a waiting stage  5  for loading a vacant boat temporarily while waiting the heat treatment and a cooling stage  6  for loading a completely processed boat to be cooled temporally at the front/rear of the heat treatment stage  4 . There is installed a wafer loading stage  7  around the central region of the front within the housing body  2  and there in installed a pod stage  8  at the front of the wafer loading state  7 . There is installed a notch alignment device  9  at the left of the wafer loading stage  7 . The construction of each stage will be illustrated.  
     [0027] As shown in FIGS. 5 and 6, there is incorporated a process tube  11  vertically with the central line thereof to be vertical, wherein the process tube  11  with the lower part thereof opened is integrally made of quartz glass. The central cavity region of the process tube  11  forms a processing room  12  in which the boat is used to bring a plurality of wafers, the plurality of wafers being concentrically arranged, and the opening in the lower part of the process tube  11  constitutes a furnace inlet  13  for taking the wafers as the substrates to be processed in and out of. Accordingly, the internal diameter of the process tube  11  is set to be larger than the maximum external diameter of wafers to be processed.  
     [0028] The lower end of the process tube  11  is maintained to be contacted with the upper surface of a manifold  14  with a seal ring  15  inserted therebetween and the manifold  14  is supported by the housing body  2  so that the process tube  11  may be maintained to be supported vertically. An exhaust pipe  16  is connected to the processing room  12  through a portion of the sidewall of the manifold  14  and the other end of the exhaust pipe  16  is connected to a vacuum exhaust device (not shown) for exhausting the processing room  12  to a predetermined vacuum degree. A gas inlet pipe  17  is connected with the processing room  12  through the other portion of the sidewall of the manifold  14  and the other portion of the gas inlet pipe  17  is connected to a gas providing device (not shown) for providing gas, e.g., source gas or nitrogen gas.  
     [0029] A heater unit  18  is concentrically installed surrounding the process tube  11  outside the process tube  11  and there is installed the heater unit  18  supported vertically by the housing body  2 . The heater unit  18  has a structure for heating the processing room  12  uniformly.  
     [0030] At the heat treatment stage  4 , there is installed a cap  19  under the process tube  11 , wherein the cap  19  having the shape of a discus is concentrically arranged and the diameter of the cap  19  is substantially equal to the outer diameter of the process tube  11 . The cap  19  is controlled to be lift upwardly or downwardly by the elevator  20  having a conveying screw device. The cap  19  is used to support the boat  21  vertically along the central line.  
     [0031] Two boats  21  are loaded to the cap  19  to be supported one after the other and then taken in and out of the process tube  11 . Two boats have basically the same design and construction but they may have an individual difference due to for example the processing deviation, the fabrication deviation, the washing by an etching process. Since two boats  21  have basically the same design and construction, only one boat  21  will be illustrated on behalf of two boats  21  except two boats  21  are required to be distinguished.  
     [0032] As shown in FIGS. 5 and 6, the boat  21  has one set of end boards  22  and  23  and a plurality of holding members wafer  24  vertically installed between two end boards  22  and  23 , wherein  3  holding members are shown for illustration in the present embodiment. A number of holding grooves  25  are carved on each holding member  24  with the same pitch between two neighboring holding grooves in order that three corresponding holding grooves of three holding members  24  may be carved on the same plane. A wafer W may be inserted between three corresponding holding grooves  24  so that a plurality of wafers may be aligned in parallel and with the centers of the holding grooves  24  coincided with each other.  
     [0033] An adiabatic cap part  26  is formed under the lower end board  23  of the boat  21 ; and a backbone  27  is vertically projected downwards under the adiabatic cap part  26  as a column with a diameter smaller than the outer diameter of the adiabatic cap part  26 . A space in which an arm of the boat conveying apparatus is inserted as described hereinafter is formed under the lower surface of the backbone  27  under the lower surface of the adiabatic cap part  26 ; and a connection part  28  for connecting the arm with an outer neighboring part under the lower surface of the backbone  27  is also formed.  
     [0034] Referring to FIG. 1, a boat conveying apparatus  30  for conveying the boat  21  between the heat treatment stage  4  and the waiting stage  5  or the cooling stage  6  is installed between the waiting stage  5  and the cooling stage  6 . As shown in FIG. 7, the boat conveying apparatus  30  includes a selective compliance assembly robot arm (SCARA) so that it may contain a set of first arm  31  and second arm  32  which may be reciprocally rotated by about 90 degrees on a horizontal plane. Both the first arm  31  and the second arm  32  are formed on a circle and inserted into an outside of the backbone  27  of the boat  21  to be coupled with the connection part  28  of the adiabatic cap part  26  so that they may support all the boat  21  vertically.  
     [0035] As shown in FIGS. 1 and 7, a waiting die  33  for supporting the boat  21  vertically is installed on the waiting stage  5  and the first arm  31  is used to allow the boat  21  to be conveyed between the waiting plate  33  and the cap  19  of the heat treatment stage  4 . A cooling plate  34  is installed on the cooling stage  6  and the second arm  32  is used to allow the boat  21  to be conveyed between the cooling plate  34  and the cap  19  of the heat treatment stage  4 .  
     [0036] As shown in FIG. 1, the clean unit  3  for providing a clean air  35  into the housing body  2  is incorporated to inject the clean air  35  toward the waiting stage  5  and the cooling stage  6 . In other words, as shown in FIG. 8, the clean unit  3  includes an inhaling duct  36  for inhaling the clean air  35 ; and an inhaling pan  37  is installed under the lower end of the inhaling duct  36 . An exhaling duct  38  is extended long back and forth at the exhaling channel of the inhaling pan  37 . Two largely opened exhaling outlets  39  for exhaling the clean air  35  toward the waiting stage  5  and the cooling stage  6 , respectively, are installed along the back and forth side of the inhaling duct  36  within the inner surfaces of the housing body  2  of the exhaling duct  38 .  
     [0037] As shown in FIG. 1, an exhaust fan  40  is installed at a rear right corner within the housing body  2 , wherein the exhaust fan  40  is used to inhale the clean air  35  exhaled from the exhaling outlets  39  of the clean unit  3  and to exhale the clean air  35  toward the outside of the housing body  2 .  
     [0038] As shown in FIGS.  1  to  4 , a substrate transfer device  41  made by a SCARA-type robot is installed on the wafer loading stage  7 , wherein the substrate transfer device  41  allows the wafer W to be conveyed between the pod stage  8  and the waiting stage  5  so that the substrate transfer device  41  may allow the wafers mounted thereon to be conveyed between the pod and the boat  21 .  
     [0039] In other words, as shown in FIG. 9, the substrate transfer device  41  has a base  42  on which a rotary actuator  43  is installed. The rotary actuator  43  allows a first linear actuator  44  installed thereon to be rotated on the horizontal plane. The first linear actuator  44  allows a second linear actuator  45  installed thereon to be conveyed horizontally. The second linear actuator  45  allows a setup die  46  installed thereon to be conveyed horizontally. On the setup die  46 , a number of tweezers  47  (for example, 5 tweezers in the present embodiment) for supporting wafers W from the lower surface thereof are installed horizontally and arranged at a same interval. As shown in FIGS.  1  to  4 , the substrate transfer device  41  may be elevated by an elevator  48  having a conveying screw appliance.  
     [0040] Each pod stage  8  allows a front opening unified pod (FOUP: hereinafter called as a pod) to be mounted as a carrier (a wafer recipient case) for carrying the wafers. The pod  50  is formed with the shape of a substantially cubical box, wherein an opening is formed on a face of the substantially cubical box, and an attachable door  51  may be installed on the opening of the pod. When the pod is used as the carrier of the wafer, the wafer is carried in a sealed state. Accordingly, although there may be pollutants in the atmosphere, the cleanliness of the wafer can be maintained. Since, therefore, the cleanliness in the clean room in which the CVD apparatus is installed need not be high, the cost for the clean room can be reduced. Therefore, in the CVD apparatus in the present embodiment, the pod  50  may be used as a carrier for the wafers. Also, a door switch (not shown) may be installed in order to switch the door  51  of the pod  50  in the pod stage  8 .  
     [0041] Referring to FIG. 10, there is shown a block diagram for illustrating a control system of the CVD system. A control system  60  shown in FIG. 10 includes a main controller constructed by computer and a plurality of sub-controllers. The sub-controllers include a temperature sub-controller  61  for controlling temperature of the processing room, a pressure sub-controller  62  for controlling pressure of the processing room, a gas sub-controller  63  for controlling a gas flow rate of gases such as raw gas, carrier gas and/or purge gas and a machine sub-controller  64  for controlling machines such as elevators, boat conveying apparatuses and/or wafer transfer apparatuses, wherein the sub-controllers are connected by a control network  65  to a main controller  66 .  
     [0042] The main controller  66  is connected to a console (a control table)  67  which is used as display means and input means (a user interface); and a memory  68  for storing a plurality of recipes. The console  67  has at least one display, at least one keyboard and at least one mouse, wherein the display may be used to display the contents (item labels, control parameter values and so on) of the recipes and the keyboard and/or the mouse may be used to transfer the instructions of the operator.  
     [0043] As illustrated in the present embodiment of the present invention, a boat identification unit  71  of the boat identification means is constructed (programmed) within the main controller  66  and a detection apparatus (hereinafter called as a boat detection apparatus)  72  for detecting the boat is connected to the boat identification unit  71 . The boat identification unit  71  is used to identify each boat based on the detection result of the boat detection apparatus  72  and the main controller  66  is used to transmit to each sub-controller instructions corresponding to each boat based on the identification result of the boat identification unit  71 .  
     [0044] In the present embodiment, boat detection apparatuses  72  are installed on the waiting plate  33 , the cooling plate  34  and the cap  19 , respectively, and each of them is connected to its corresponding boat identification unit  71  of the main controller  66 . In the present embodiment, since boat detection apparatuses  72  respectively installed on the waiting plate  33 , the cooling plate  34  and the cap  19  have substantially same elements and constructions, the boat detection apparatus  72  installed on the waiting plate  33  shown in FIGS. 11 and 12 will be illustrated as a typical boat detection apparatus  72 .  
     [0045] As shown in FIGS. 11 and 12, the boat detection apparatus  72  is installed on the bottom of a location alignment groove caved in the upper surface of the waiting plate  33 . In other words, 3 number of location alignment grooves  81  caved in are located along the radial direction (forming the substantially Y shape) on the upper surface of the waiting plate  33  based on the center of the upper surface of the waiting plate  33 , wherein each location alignment groove  81  forms an inverse trapezoidal cross-sectional elongated groove and the boat detection apparatus  72  is located along the neighboring portion of the lower surface of one of the 3 location alignment grooves  81 . The 3 location alignment grooves  81  may be connected to 3 location alignment bosses  82  projected under the lower surface of the base  29  of the boat  21 , respectively. In other words, each of the 3 location alignment bosses  82  has shaped with a circular truncated cone which has a trapezoidal cross-section corresponding to an inverse trapezoidal cross-section of the location alignment groove  81  and has been located at a same angle interval, e.g., 120 degrees, along the circular direction in order to be inserted to the 3 the location alignment grooves  81  on a concentric circle based on the center of the lower surface of the base  29 . A location alignment ring unit  83  is projected downwards along the outer circle region of the lower surface of the base  29 , wherein the location alignment ring unit  83  has an arm taper-shaped unit  84  along the inner surface of the location alignment ring unit  83 . The arm taper-shaped unit  84  of the location alignment ring unit  83  is to be inserted to the outer circle surface of the waiting plate  33 .  
     [0046] As shown in FIGS. 11 and 12, the boat detection apparatus  72  includes a boat detection unit  73  for detecting whether there exists a boat  21  on the waiting plate  33  and a boat identifying detection unit  74  for identifying the boat  21  mounted on the waiting plate  33 , wherein the boat detection unit  73  and the boat identifying detection unit  74  have substantially same elements and constructions. In other words, both the boat detection unit  73  and the boat identifying detection unit  74  include a holding hole  75  formed on the bottom of the location alignment groove  81 , a plug  76  formed to be able to slide up and down along the holding hole  75 , a spring  77  for always pressing the plug  76  upwards and a limit switch  78  for detecting the up and down movement of the plug  76 , wherein the plug  76  detects a detected body  79  projected on the lower surface of the base  29  of the boat  21  so that the limit switch  78  may be switched. In addition, the plug  76  is formed of a material, e.g., fluorine resin, with heat resistance and abrasion resistance.  
     [0047] As shown in FIGS. 11E and 12D, the detected body  79  projected on the lower surface of the base  29  has a screw structure and may be adhered with an attachable structure to the lower surface of the base  29  formed by quartz or SiC. In the present embodiment, the detected body  79  corresponding to the boat identifying detection unit  74  is mounted on one boat (hereinafter called as a first boat)  21 A, but is not mounted on the other boat (hereinafter called as a second boat)  21 B. Therefore, if the boat identifying detection unit  74  detects the detected body  79 , the boat may be determined as the first boat  21 A and, if otherwise, the boat may be determined as the second boat  21 B.  
     [0048] Hereinafter, a CVD technique within the substrate processing method by using the CVD apparatus described above in accordance with the present invention will be described based on a handling method of a pair of boats.  
     [0049] The CVD method is performed by a control sequence for executing a recipe of a film forming processes determined beforehand, wherein the recipe is installed on the RAM of the main controller  66  from the memory  68  and is instructed to the sub-controllers  62  to  64  to be implemented.  
     [0050] First of all, the first boat  21 A is conveyed by the boat conveying apparatus  30  and mounted on the waiting plate  33  of the waiting stage  5 . The wafers W stacked into the pod  50  are conveyed by the substrate transfer device  41  and, then, mounted on the first boat  21 A. In other words, as shown in FIGS. 1 and 2, the first boat  21 A is conveyed by the boat conveying apparatus  30  and mounted on the waiting plate  33  of the waiting stage  5 . Meanwhile, as shown in FIG. 1, the pod  50  which has a plurality of wafers is provided to the pod stage  8  and, as shown in FIG. 2, door switching means allows a door  51  of the pod  50  provided to the pod stage  8  to be open.  
     [0051] Referring to FIGS. 9A and 9B, the second linear actuator  45  and the setup plate  46  are moved in the direction of the pod  50  so that the tweezers  47  may be inserted into the pod  50  and allowed to receive the wafers in the pod  50 . Then, the tweezers  47  return to the location shown in FIG. 9A. Then, the rotary actuator  43  is reversed so that the second linear actuator  45  and the setup plate  46  may move to the waiting stage  5  and the wafers W held by the tweezers  47  are replaced with those held by the holding grooves  25  of the first boat  21 A. After the substrate transfer device  41  conveys the wafers W to the first boat  21 A and mounts the wafers W on the first boat  21 A, it returns back and, then, reverses the second linear actuator  45  and the setup plate  46  so that the tweezers  47  may be disposed toward the pod  50  as shown in FIGS. 9A and 9B.  
     [0052] Since, as shown in FIG. 12A, both the boat detection unit  73  and the boat identifying detection unit  74  in the waiting plate  33  detect two detected bodies  79  of the base  29 , the boat identification unit  71  of the control system  60  determines the boat is the first boat  21 A and transmits the determining result to the main controller  66 . In other words, if two detection signals are transmitted from both the boat detection unit  73  and the boat identifying detection unit  74 , the boat identification unit  71  determines that the first boat  21 A presents on the waiting plate  33 . The main controller  66  informs the machine sub-controller  64  of the control condition corresponding to the first boat  21 A so that it may allow the substrate transfer device  41  to control the wafer transfer process. The control condition corresponding to the first boat  21 A includes a pitch of the holding groove  25  for holding the wafer and a center for defining 3 holding grooves  25  stretched into 3 directions.  
     [0053] If the first boat  21 A is mounted on the waiting plate  33 , since each of 3 location alignment bosses  82  projected on the base  29  of the first boat  21 A is inserted into its corresponding location alignment groove  81  which is caved in radially on the waiting plate  33 , the first boat  21 A is axially aligned with the waiting plate  33  and directs in the predetermined direction. In other words, the wafer insertion direction defined by 3 holding members  24  of the first boat  21 A is exactly consistent with the forwarding direction of tweezers  47  of the substrate transfer device  41 . Accordingly, the transfer process may be preferably performed by the substrate transfer device  41 .  
     [0054] If N number of wafers are loaded on the first boat  21 A, N being a positive integer determined by the waiting stage  5 , the first boat  21 A is conveyed from the waiting stage  5  to the heat treatment stage  4  by the first arm  31  of the boat conveying apparatus  30  as shown in FIG. 4 so that it may be conveyed to and mounted on the cap  19 . In other words, the first arm  31  is inserted along the outside of the backbone  27  of the first boat  21 A and connected with the connection part  28  of the adiabatic cap part  26  through the lower part of the first arm  31 . Then, the first arm  31  may be rotated by about 90 degrees with the first boat  21 A supported vertically so that the first boat  21 A may be conveyed from the waiting stage  5  to the heat treatment stage  4  and may be given to or taken from the cap  19 . After the first arm  31  allows the first boat  21 A to be conveyed to and mounted on the cap  19 , the first arm  31  returns to the waiting stage  5 .  
     [0055] Since the boat detection apparatus  72  and the location alignment groove  81  are also arranged on the cap  19  as arranged on the waiting plate  33 , the first boat  21 A conveyed to and mounted on the cap  19  will be exactly aligned and the boat identification unit  71  determines the presence of the first boat  21 A and, if any, identifies the type of the first boat  21 A. The main controller  66  informs the temperature sub-controller  61 , the pressure sub-controller  62  and the gas sub-controller  63  of the control conditions corresponding to the first boat  21 A. The control condition corresponding to the first boat  21 A may include a gas providing control corresponding to a pitch of the holding groove  25  for holding the wafer and a center for defining 3 holding grooves  25  stretched into 3 directions.  
     [0056] As shown in FIG. 5, the elevator  20  is used to lift the first boat  21 A vertically supported by the cap  19  so that the first boat  21 A is inputted into the processing room  12  of the process tube  11 . If the first boat  21 A arrives at the top, since the outer neighboring portion of the upper surface of the cap  19  and the lower surface of the manifold  14  are maintained with the seal ring  15  inserted therebetween so that the lower end opening of the manifold  14  is closed in a sealing state, so that the processing room  12  turns to be in a state of sealing state.  
     [0057] If the cap  19  is used to close the processing room  12  in the sealing state, the exhaust pipe  16  is used to produce a vacuum in the processing room  12  to a predetermined degree of vacuum and a heating unit  18  is used to heat the processing room  12  totally and uniformly to a predetermined processing temperature (e.g., 800 to 1000 degrees). If the temperature in the processing room  12  is stabilized, the processing gas is introduced to the processing room  12  through the gas inlet pipe  17  with a predetermined flow rate. Therefore, a predetermined film formation process may be performed.  
     [0058] While the film formation process is performed on the first boat  21 A, the boat conveying apparatus  30  is used to convey the second boat  21 B to the waiting plate  33 , mounted thereon, of the waiting stage  5  and the substrate transfer device  41  is used to charge the wafers W on the pod  50  to the second boat  21 B. Since each of 3 location alignment bosses  82  projected on the base  29  of the second boat  21 B is inserted into its corresponding location alignment groove  81  which is caved in radially on the waiting plate  33 , the second boat  21 B is axially aligned with the waiting plate  33  and directs in the predetermined direction. In other words, the transfer process on the second boat  21 B of the wafer W may be preferably performed by the substrate transfer device  41 .  
     [0059] Since the detected body  79  corresponding to the boat identifying detection unit  74  is not mounted on the base  29  of the second boat  21 B, the boat detection unit  73  in the boat detection apparatus  72  detects the detected body  79  while the boat identifying detection unit  74  has not detected the detected body  79 . So the boat identification unit  71  of the control system  60  determines the boat to be the second boat  21 B and transmits the determining result to the main controller  66 . In other words, if the detection signal is transmitted from only the boat detection unit  73 , the boat identification unit  71  determines the second boat  21 B presents on the waiting plate  33 . The main controller  66  informs the machine sub-controller  64  of the control condition corresponding to the second boat  21 B so that the main controller  66  allows the substrate transfer device  41  to control the wafer transfer (charging) process as described above.  
     [0060] In the meantime, if a predetermined processing time is elapsed for the first boat  21 A inserted in the process tube  11 , the cap  19  for holding the first boat  21 A is dropped by the elevator  20 , as shown in FIG. 6, so that the first boat  21 A may be taken out of the processing room  12  of the process tube  11 . While the first boat  21 A is taken out of the processing room  12  of the process tube  11 , the wafers held by the first boat  21 A continues to be in a high temperature state.  
     [0061] The first boat  21 A completely processed in the high temperature is taken out of the processing room  12  so that it may be immediately conveyed from the heat treatment stage  4  on the same axial line of the process tube  11  to the cooling stage  6  by the second arm  32  of the boat conveying apparatus  30  as shown in FIG. 3. The second arm  32  is inserted along the outside of the backbone  27  of the second boat  21 B completely processed so that it may be connected with the connection part  28  of the adiabatic cap part  26  through the lower part of the second arm  32 . Then, the second arm  32  may rotate the first boat  21 A completely processed by about 90 degrees while the first boat  21 A being supported vertically so that the first boat  21 A may be conveyed to and mounted on the cooling plate  34  of the cooling stage  6  from the cap  19  of the heat treatment stage  4 .  
     [0062] Since the boat detection apparatus  72  and the location alignment groove  81  are likely arranged in the cooling plate  34  as arranged in the waiting plate  33 , the first boat  21 A conveyed to and mounted on the cooling plate  34  is exactly aligned and both the detection of the existence of the first boat  21 A and the identification of the type thereof may be performed by the boat identification unit  71 .  
     [0063] Since, as shown in FIG. 4, the cooling stage  6  is located near to the clean air exhaling outlet  39  of the clean unit  3 , the high-temperature first boat  21 A conveyed to and mounted on the cooling plate  34  of the cooling stage  6  may be effectively cooled by the clean air  35  exhaled from the exhaling outlet  39  of the clean unit  3 .  
     [0064] After the first boat  21 A on the cooling plate  34  is cooled down to for example lower than 150° C., the first boat  21 A is conveyed by the boat conveying apparatus  30  through the heat treatment stage  4  to the waiting stage  5 . In other words, the second arm  32  of the boat conveying apparatus  30  is inserted along the outside of the backbone  27  of the first boat  21 A so that it may be connected with the connection part  28  of the adiabatic cap part  26  through the lower part of the first arm  31 . Then, the second arm  32  may be rotated by about 90 degrees with the first boat  21 A supported vertically so that the first boat  21 A may be conveyed from the cooling stage  6  to the heat treatment stage  4 . If the first boat  21 A is conveyed to the heat treatment stage  4 , the first arm  31  of the boat conveying apparatus  30  is rotated by about 90 degrees toward the heat treatment stage  4  so that it may receive the first boat  21 A of the heat treatment stage  4 . After the first boat  21 A is received, the first arm  31  is reversely rotated by 90 degrees to the original location so that the first boat  21 A may be conveyed from the heat treatment stage  4  to the waiting stage  5  and mounted on the waiting plate  33 . If the first boat  21 A is conveyed to and mounted on the waiting plate  33 , three holding members  24  of the first boat  21 A allow the substrate transfer device  41  to be open.  
     [0065] If the first boat  21 A returns to the waiting plate  33 , the substrate transfer device  41  receives the completely processed wafer W from the first boat  21 A of the waiting plate  33  so that the wafers are conveyed to and mounted on the pod  50  of the pod stage  8 . Since, as shown in FIG. 12A, both the boat detection unit  73  and the boat identifying detection unit  74  have detected both of the detected bodies  79  of the base  29 , the boat identification unit  71  of the control system  60  determines the boat as the first boat  21 A and transmits the determination result to the main controller  66 . The main controller  66  informs the machine subcontroller  64  of the control condition corresponding to the first boat  21 A so that it may allow the substrate transfer device  41  to control the wafer transfer process (discharging process) from the first boat  21 A to the pod  50 .  
     [0066] Since each of the 3 location alignment bosses  82  projected on the base  29  of the first boat  21 A is inserted into its corresponding location alignment groove  81  which is caved in radially on the waiting plate  33 , the first boat  21 A is axially aligned with the waiting plate  33  and directs in the predetermined direction. Accordingly, the process for discharging the wafer from the first boat  21 A to the pod  50  may be preferably performed by the substrate transfer device  41 .  
     [0067] If all the completely processed wafers return to the pod  50 , a new wafer W to be processed next is charged on, i.e., conveyed to and mounted on, the first boat  21 A of the waiting plate  33  by the substrate transfer device  41 .  
     [0068] The operation will be repeated between the first boat  21 A and the second boat  21 B so that a plurality of wafers may be processed by the CVD apparatus  1 .  
     [0069] In accordance with the present invention, the effects are obtained as follows.  
     [0070] (1) Since the boat identification unit  71  identifies either the first boat  21 A or the second boat  21 B based on the detection signal from the boat detection apparatus  72  of the boat identification means so that the main controller  66  may adequately instruct the control condition of the substrate transfer device  41  which corresponds exactly to either the first boat  21 A or the second boat  21 B, the transfer process of the substrate transfer device  41  may be prevented from failing due to a difference between the first boat  21 A and the second boat  21 B.  
     [0071] (2) Since the boat identification unit  71  identifies either the first boat  21 A or the second boat  21 B based on the detection signal from the boat detection apparatus  72  of the boat identification means so that the main controller  66  may adequately generates control conditions of the temperature sub-controller  61 , the pressure sub-controller  62  and gas sub-controller  63  which correspond to either the first boat  21 A or the second boat  21 B, the quality and credibility in the CVD method may be increased.  
     [0072] (3) Since the adjustment of the control conditions results in the change of the conditions for manufacturing a film on the wafer, a difference load set between the first boat  21 A and the second boat  21 B may be used and only one CVD apparatus  1  may be used to make a plurality of films.  
     [0073] (4) Three boat detection apparatuses  72  are arranged on the waiting plate  33 , the cooling plate  34  and the cap  19 , respectively, the current location of the first boat  21 A and the second boat  21 B may be detected. Since, for example, the locations of the first boat  21 A and the second boat  21 B are exactly detected at the beginning of the process for making the film after the lightout is recovered, the next processes on the first boat  21 A and the second boat  21 B may be exactly performed.  
     [0074] (5) If the moving history of the boat may be stored in a file based on the boat detection unit  73 , the location of the boat  21  may be identified. Since, however, the identification on the location of the boat  21  is no more than a prediction, it may result in a malfunction and an accident. Since, however, the detection of the first boat  21 A and the second boat  21 B as described in (4) eliminates the necessity of the prediction of the locations of the first boat  21 A and the second boat  21 B, the malfunction and the accident can be prevented in advance in accordance with the present invention.  
     [0075] (6) Since the detected body  79  may be attachable and detachable to the boat  21  so that the structure difference between the first boat  21 A and the second boat  21 B need not be set, the manufacturing cost may be prevented from increasing.  
     [0076] The present invention is not confined to the present embodiment and may be modified without deviating the essence of the present invention.  
     [0077] For example, three boat detection apparatus of the boat identification means are not confined to be arranged on the waiting stage, the cooling stage and the heat treatment stage, respectively. It is enough that one boat detection apparatus is arranged on at least one stage, e.g., the waiting stage in the above present embodiment, on which the wafer transfer process is performed.  
     [0078] If the boat detection apparatus of the boat identification means is also arranged on the arm of the boat conveying apparatus, the location of the boat may be detected while the boat is conveyed.  
     [0079] The detected body of the boat identification means is not confined to a screw structure but the structure in which the base may be attachable to the boat may be used.  
     [0080] The CVD apparatus may be used to perform all the CVD processes, such as, an annealing process, an oxide film formation process, a diffusion process and a film making process.  
     [0081] Although the embodiment has been confined to the case for processing the wafer, a hot mask, print wiring substrate, liquid crystal panel, compact disc and magnetic disc and so on may be used.  
     [0082] While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.