Patent Publication Number: US-7222721-B2

Title: Transferring apparatus, carrying apparatus, and transferring method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional patent application of U.S. Ser. No. 10/798,975 filed Mar. 11, 2004 now U.S. Pat. No. 7,051,863, claiming priority to Japanese Patent Application No. 2003-067296 filed Mar. 12, 2003 and 2003-434184 filed Dec. 26, 2003 which are hereby expressly incorporated by reference herein in their entireties. 

   BACKGROUND 
   1. Technical Field of the Invention 
   The present invention relates to a transferring apparatus for transferring a carried product, a carrying apparatus, and a transferring method. 
   2. Description of the Related Art 
   Recently, as so-called IT industry has developed, various electronic devices such as semiconductor devices and liquid crystal display devices have been developed. For manufacturing the electronic devices, for example, the semiconductor devices, processing apparatuses for performing processes such as photolithography, film formation, etching and cleaning processes and carrying apparatuses for carrying substrates or substrate wafers between the processing apparatuses are used. 
   For the carrying apparatus, since it is necessary to prepare a facility capable of obtaining carrying amounts needed to efficiently produce the devices in the manufacturing facility capable of obtaining product amounts corresponding to demands for the devices, various types of carrying apparatuses capable of efficiently performing carrying have been developed. Recently, since the tendency of the production changes from limit-type mass production to wide-type small production, suitable carrying apparatuses have been contrived and methods of carrying the wafers one by one have been proposed. Specifically, the carrying apparatus comprises, for example, a conveyor between processing apparatuses for processing the semiconductor wafers and the length of the conveyor is predetermined to cope with the demands for the semiconductor devices (for example, see Japanese Unexamined Patent Application Publication No. 2001-233450 (see FIG. 1)). 
   When there arises a need to increase production according to the change of the demands forecast of the semiconductor devices, there is a need to add manufacturing apparatuses for ensuring the production and carrying apparatuses for carrying wafers or substrates between the added manufacturing apparatuses as well as between the existing and added carrying apparatuses. However, the conventional conveyor has a problem in that it cannot be easily added because it is impossible to transfer the semiconductor wafers between the existing and added conveyors. 
   Accordingly, an object of the present invention is to provide a transferring apparatus, a carrying apparatus, and a transferring method for solving the above problems and facilitating extension of carrying apparatuses. 
   SUMMARY 
   The object can be achieved by a first aspect of the present invention, which provides a transferring apparatus provided between a plurality of carrying apparatuses, each carrying apparatus comprising support means for supporting carried products, guide means for controlling the moving direction of the support means, the guide means being provided along a processing apparatus for processing the carried products, and moving means for moving the support means along the guide means, the transferring apparatus comprising: synchronization control means for synchronizing the moving means of one carrying apparatus with the moving means of another carrying apparatus; and at least one hand-over means for receiving the carried products from the support means of the one carrying apparatus and handing over the carried products to the support means of the other carrying apparatus. 
   According to the construction, when adding a new manufacturing apparatus, if the existing carrying apparatus has an insufficient carrying ability, and the new manufacturing apparatus can not be connected to the existing carrying apparatus, for example, a to-be-added carrying apparatus is installed and, the carried products are transferred by the transferring apparatus between the added and existing carrying apparatuses. Specifically, in the transferring apparatus, moving means of the one carrying apparatus is- synchronized with moving means of the other carrying apparatus and the carried products are received from the support means of the one carrying apparatus and handed over to the support means of the other carrying apparatus by the hand-over means. Accordingly, it suffices to consider a currently needed minimum ability of carrying the carried products when initially providing a carrying apparatus and it is possible to simply install additional carrying apparatuses if later needed. 
   A second aspect of the present invention provides a transferring apparatus according to the 1st aspect of the present invention, wherein the hand-over means receives some carried products selected among the plurality of carried products which are carried by the one carrying apparatus. 
   According to the construction, since the carried products which need to be carried only by the one carrying apparatus are not handed over to the other carrying apparatus by the hand-over means, the carried products can be efficiently carried. 
   A third aspect of the present invention provides a transferring apparatus according to the 1st aspect of the present invention, wherein the hand-over means receives all the carried products which are carried by the one carrying apparatus. 
   According to the construction, since the hand-over means receives all the carried products from the one carrying apparatus, it is not necessary for the hand-over means to determine whether there is a carried product to receive. As a result, it is possible to easily obtain the timing of handing over the carried products between the carrying apparatuses. For this reason, since the synchronization control means can be easily controlled, it is possible to implement an easily-controlled transferring apparatus. 
   A fourth aspect of the present invention provides a transferring apparatus according to one of the 1st to 3rd aspects of the present invention, further comprising at least one buffer means for temporarily storing the carried products between the one carrying apparatus and the other carrying apparatus. 
   According to the construction, even when the carried products received from the support means of the one carrying apparatus are not immediately handed over to the support means of the other carrying apparatus, the carried products can be temporarily stored. As a result, the carried products can be handed over according to the carrying state of the other carrying apparatus. 
   A fifth aspect of the present invention provides a transferring apparatus according to the fourth aspect of the present invention, wherein the transferring apparatus is integrated with each of the carrying apparatuses. 
   According to the construction, when adding a new carrying apparatus in order to increase the ability of carrying the carried products, the transferring apparatus that is originally or previously connected to be integrated with the to-be-added carrying apparatus may be connected to the existing carrying apparatus, or only the to-be-added carrying apparatus may be installed, with the transferring apparatus being originally or previously connected to be integrated with the existing carrying apparatus. That is, the transferring apparatus integrated with the carrying apparatuses can carry the carried products between the one and the other carrying apparatuses. 
   A sixth aspect of the present invention provides a transferring apparatus according to the fifth aspect of the present invention, wherein each of the carried products is a substrate wafer. 
   A seventh aspect of the present invention provides a transferring apparatus according to the sixth aspect of the present invention, wherein the substrate wafer is a semiconductor wafer. 
   An eighth aspect of the present invention provides a transferring apparatus according to the fifth aspect of the present invention, wherein each of the carried products is an electronic device manufacturing substrate. 
   A ninth aspect of the present invention provides a transferring apparatus according to the eighth aspect of the present invention, wherein the electronic device manufacturing substrate is a liquid crystal device substrate. 
   A tenth aspect of the present invention provides a transferring apparatus according to the eighth aspect of the present invention, wherein the electronic device manufacturing substrate is a quartz device substrate. 
   An eleventh aspect of the present invention provides a transferring apparatus according to the fourth aspect of the present invention, wherein each of the buffer means is provided in combination with each, of the hand-over means. 
   According to the construction, since the buffer means is provided for every hand-over means, the hand-over means can be easily controlled. 
   A twelfth aspect of the present invention provides a transferring apparatus according to the fourth aspect of the present invention, wherein the buffer means is shared by the plurality of the hand-over means. 
   According to the construction, since the number of buffer means is small, it is possible to provide an easily-controlled low-cost transferring apparatus. 
   A thirteenth aspect of the present invention provides a transferring apparatus according to the first, second, eleventh, or twelfth aspect of the present invention, wherein each of the carried products is a substrate wafer. 
   A fourteenth aspect of the present invention provides a transferring apparatus according to the thirteenth aspect of the present invention, wherein the substrate wafer is a semiconductor wafer. 
   A fifteenth aspect of the present invention provides a transferring apparatus according to the first, second, eleventh, or twelfth aspect of the present invention, wherein each of the carried products is an electronic device manufacturing substrate. 
   A sixteenth aspect of the present invention provides a transferring apparatus according to the fifteenth aspect of the present invention, wherein the electronic device manufacturing substrate is a liquid crystal device substrate. 
   A seventeenth aspect of the present invention provides a transferring apparatus according to the fifteenth aspect of the present invention, wherein the electronic device manufacturing substrate is a quartz device substrate. 
   An eighteenth aspect of the present invention provides a transferring apparatus according to the first, second, eleventh, or twelfth aspect of the present invention, wherein the transferring apparatus is integrated with each of the carrying apparatuses. 
   According to the construction, when adding a new carrying apparatus in order to increase the ability of carrying the carried products, the transferring apparatus that is originally or previously connected to be integrated with the to-be-added carrying apparatus may be connected to the existing carrying apparatus, or only the to-be-added carrying apparatus may be installed, with the transferring apparatus being originally or previously connected to be integrated with the existing carrying apparatus. That is, the transferring apparatus integrated with the carrying apparatuses can carry the carried products between the one and the other carrying apparatuses. 
   A nineteenth aspect of the present invention provides a transferring apparatus according to the eighteenth aspect of the present invention, wherein each of the carried products is a substrate wafer. 
   A twentieth aspect of the present invention provides a transferring apparatus according to the nineteenth aspect of the present invention, wherein the substrate wafer is a semiconductor wafer. 
   A twenty-first aspect of the present invention provides a transferring apparatus according to the eighteenth aspect of the present invention, wherein each of the carried products is an electronic device manufacturing substrate. 
   A twenty-second aspect of the present invention provides a transferring apparatus according to the twenty-first aspect of the present invention, wherein the electronic device manufacturing substrate is a liquid crystal device substrate. 
   A twenty-third aspect of the present invention provides a transferring apparatus according to the twenty-first aspect of the present invention, wherein the electronic device manufacturing substrate is a quartz device substrate. 
   The object can be achieved by a twenty-fourth aspect of the present invention, which provides a carrying apparatus comprising: a plurality of carrying means, each carrying means comprising support means for supporting carried products, guide means for controlling the moving direction of the support means, the guide means being provided along a processing apparatus for processing the carried products, and moving means for moving the support means along the guide means; and transferring means being provided between the plurality of carrying means, wherein the transferring means comprises: synchronization control means for synchronizing the moving means of one carrying means with the moving means of another carrying means; and at least one hand-over means for receiving the carried products from the support means of the one carrying means and handing over the carried products to the support means of the other carrying means. 
   According to the construction, when adding a new manufacturing apparatus, if the existing carrying means has an insufficient carrying ability, and the manufacturing apparatus can not be connected to the existing carrying means for example, it suffices that the to-be-added carrying apparatus is installed and, the carried products are transferred by the transferring apparatus between the added carrying means and the existing carrying means. Specifically, in the transferring apparatus, moving means of one carrying means is synchronized with moving means of another carrying means and the carried products are received from the support means of the one carrying apparatus and handed over to the support means of the other carrying means by the hand-over means. Accordingly, it is sufficient to consider a currently needed minimum ability of carrying the carried products at the time of initially providing carrying means and it is possible to simply install additional carrying means if later needed. 
   A twenty-fifth aspect of the present invention provides a carrying apparatus according to the twenty-fourth aspect of the present invention, wherein the hand-over means receives some carried products selected among the plurality of the carried products which are carried by the one carrying means. 
   According to the construction, since the carried products which need to be carried only by the one carrying means are not handed over to the other carrying means by the hand-over means, the carried products can be efficiently carried. 
   A twenty-sixth aspect of the present invention provides a carrying apparatus according to the twenty-fourth aspect of the present invention, wherein the hand-over means receives all the carried products which are carried by the one carrying means. 
   According to the construction, since the hand-over means receives all the carried products from-the one carrying means, it is not necessary for the hand-over means to determine whether there is a carried product to receive. As a result, it is possible to easily obtain the timing of handing over the carried products between the carrying means. For this reason, since the synchronization control means can be easily controlled, it is possible to implement an easily-controlled carrying apparatus. 
   A twenty-seventh aspect of the present invention provides a carrying apparatus according to one of the twenty-fourth to twenty-sixth aspects of the present invention, further comprising at least one buffer means for temporarily storing the carried products between the one carrying means and the other carrying means. 
   According to the construction, even when the carried products received from the support means of the one carrying means cannot be immediately handed over to the support means of the other carrying means, the carried products can be temporarily stored. As a result, the carried products can be handed over according to the carrying state of the other carrying means. 
   A twenty-eighth aspect of the present invention provides a carrying apparatus according to the twenty-seventh aspect of the present invention, wherein the transferring means is integrated with each of the carrying means. 
   According to the construction, when adding a new carrying means in order to increase the ability of carrying the carried products, the transferring apparatus that is originally or previously connected to be integrated with the to-be-added carrying means may be connected to the existing carrying means, or only the to-be-added carrying means may be installed, with the transferring apparatus being originally or previously connected to be integrated with the existing carrying means. That is, the transferring apparatus integrated with the carrying means can carry the carried products between the one and other carrying means. 
   A twenty-ninth aspect of the present invention provides a carrying apparatus according to the twenty-eighth aspect of the present invention, wherein each of the carried products is a substrate wafer. 
   A thirtieth aspect of the present invention provides a carrying apparatus according to the twenty-ninth aspect of the present invention, wherein the substrate wafer is a semiconductor wafer. 
   A thirty-first aspect of the present invention provides a carrying apparatus according to the twenty-eighth aspect of the present invention, wherein each of the carried products is an electronic device manufacturing substrate. 
   A thirty-second aspect of the present invention provides a carrying apparatus according to the thirty-first aspect of the present invention, wherein the electronic device manufacturing substrate is a liquid crystal device substrate. 
   The thirty-third aspect of the present invention provides a carrying apparatus according to the thirty-first aspect of the present invention, wherein the electronic device manufacturing substrate is a quartz device substrate. 
   A thirty-fourth aspect of the present invention provides a carrying apparatus according to the twenty-seventh aspect of the present invention, wherein each of the buffer means is provided in combination with each of the hand-over means. 
   According to the construction, since the buffer means is provided for every hand-over means, the hand-over means can be easily controlled. 
   A thirty-fifth aspect of the present invention provides a carrying apparatus according to the twenty-seventh aspect of the present invention, wherein the buffer means is shared by the plurality of the hand-over means. 
   According to the construction, since the number of buffer means is small, it is possible to provide an easily-controlled, low-cost transferring apparatus. 
   A thirty-sixth aspect of the present invention provides a carrying apparatus according to the twenty-fourth, twenty-fifth, thirty-fourth, or thirty-fifth aspect of the present invention, wherein each of the carried products is a substrate wafer. 
   A thirty-seventh aspect of the present invention provides a carrying apparatus according to the thirty-sixth aspect of the present invention, wherein the substrate wafer is a semiconductor wafer. 
   A thirty-eighth aspect of the present invention provides a carrying apparatus according to the twenty-fourth, twenty-fifth, thirty-fourth, or thirty-fifth aspect of the present invention, wherein each of the carried products is an electronic device manufacturing substrate. 
   A thirty-ninth aspect of the present invention provides a carrying apparatus according to the thirty-eighth aspect of the present invention, wherein the electronic device manufacturing substrate is a liquid crystal device substrate. 
   A fortieth aspect of the present invention provides a carrying apparatus according to the thirty-eighth aspect of the present invention, wherein the electronic device manufacturing substrate is a quartz device substrate. 
   A forty-first aspect of the present invention provides a carrying apparatus according to the twenty-fourth, twenty-fifth, thirty-fourth, or thirty-fifth aspect of the present invention, wherein the transferring means is integrated with each of the carrying means. 
   According to the construction, when adding a new carrying means in order to increase the ability of carrying the carried products, the transferring apparatus that is originally or previously connected to be integrated with the to-be-added carrying means may be connected to the existing carrying means, or only the to-be-added carrying means may be installed, with the transferring apparatus being originally or previously connected to be integrated with the existing carrying means. That is, the transferring apparatus integrated with the carrying means can carry the carried products between the one carrying means and the other carrying means. 
   A forty-second aspect of the present invention provides a carrying apparatus according to the forty-first aspect of the present invention, wherein each of the carried products is a substrate wafer. 
   A forty-third aspect of the present invention provides a carrying apparatus according to the forty-second aspect of the present invention, wherein the substrate wafer is a semiconductor wafer. 
   A forty-fourth aspect of the present invention provides a carrying apparatus according to the forty-first aspect of the present invention, wherein each of the carried products is an electronic device manufacturing substrate. 
   A forty-fifth aspect of the present invention provides a carrying apparatus according to the forty-fourth aspect of the present invention, wherein the electronic device manufacturing substrate is a liquid crystal device substrate. 
   A forty-sixth aspect of the present invention provides a carrying apparatus according to the forty-fourth aspect of the present invention, wherein the electronic device manufacturing substrate is a quartz device substrate. 
   The object can be achieved by a forty-seventh aspect of the present invention, which provides a transferring method being performed between a plurality of carrying apparatuses, each carrying apparatus comprising support means for supporting carried products, guide means for controlling the moving direction of the support means, the guide means being provided along processing apparatus for processing the carried products, and moving means for moving the support means along the guide means, wherein, while the moving means of one carrying apparatus is synchronized with the moving means of another carrying apparatus, the carried products are received from the support means of the one carrying apparatus and handed over to the support means of the other carrying apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view illustrating an example of an external view of a semiconductor manufacturing apparatus comprising a transferring unit. 
       FIG. 2  is a perspective view illustrating an example of a detailed construction including the transferring unit of  FIG. 1 . 
       FIG. 3  is a block diagram illustrating an example of an electrical construction of the transferring unit of  FIG. 2 . 
       FIG. 4  is a perspective view illustrating an example of an external view of a transferring robot of  FIG. 1  or  2 . 
       FIG. 5  is a perspective view illustrating an example of a state in which a wafer is scooped. 
       FIG. 6  is a perspective view illustrating an example of a state in which a single wafer carrying apparatus is added. 
       FIG. 7  is a perspective view illustrating an example of a construction of a transferring unit and the like. 
       FIG. 8  is a perspective view illustrating an example of a construction of a transferring unit and the like. 
       FIG. 9  is a perspective view illustrating an example of a construction of a transferring unit and the like. 
       FIG. 10  is a perspective view illustrating an example of a construction of a transferring unit and the like. 
       FIG. 11  is a perspective view illustrating an example of a construction of a transferring unit and the like. 
       FIG. 12  is a perspective view illustrating an example of a detailed construction of a transferring unit and the like. 
       FIG. 13  is a perspective view illustrating an example of a detailed construction of a transferring unit and the like. 
       FIG. 14  is a perspective view illustrating an example of a construction of a transferring hand portion. 
       FIG. 15  is a perspective view illustrating an example of an operational state of a transferring unit and the like. 
       FIG. 16  is a perspective view illustrating an example of an operational state of a transferring unit and the like. 
       FIG. 17  is a perspective view illustrating an example of an operational state of a transferring unit and the like. 
       FIG. 18  is a perspective view illustrating an example of an operational state of a transferring unit and the like. 
       FIG. 19  is a perspective view illustrating an example of an operational state of a transferring unit and the like. 
       FIG. 20  is a perspective view illustrating an example of an operational state of a transferring unit and the like. 
   

   DETAILED DESCRIPTION 
   Now, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. 
   Since the following described embodiments are only the exemplary of the present invention, the technically preferred limitation is added to the embodiments. However, the scope of the present invention is not limited thereto. 
   First Embodiment 
     FIG. 1  is a perspective view illustrating an example of an external view of a semiconductor manufacturing apparatus  100  including a transferring unit  1  to which a transferring apparatus as a first embodiment of the present invention is adapted. In  FIG. 1  and the following figures, a clean tunnel for increasing cleanliness around semiconductor wafers Wf is omitted. The semiconductor wafer is an example of products which are carried between processing apparatuses  23  and the like, and referred to as a wafer in the following embodiments. It is understood that the carried product is not limited to the wafer but may be, among others, a substrate wafer or an electronic device manufacturing substrate. 
   The semiconductor manufacturing apparatus  100  of  FIG. 1  comprises processing apparatuses  23  to  27  and a single wafer carrying apparatus  20  and has a construction capable of adding another single wafer carrying apparatus  120 . Each of the single wafer carrying apparatuses  20  and  120  comprises a cover and a cleaning device (not shown in the drawing), so that the ambient of a region through which the wafers Wf pass can be isolated from the external ambient and maintained to be clean. The construction of the single wafer carrying apparatus  120  is the same as that of the single wafer carrying apparatus  20 , and description thereof is omitted. 
   One of the characteristics of the embodiment is that the semiconductor manufacturing apparatus  100  uses transferring units  1  at the time of adding the single wafer carrying apparatus  120 . The transferring units  1  are provided, for example, near both sides of a connection portion of the single wafer carrying apparatuses  20  and  120 . It is noted that the transferring unit  1  may be provided on only one side rather than on both sides of the connection portion. 
   Since each transferring unit  1  comprises a cover and a cleaning device (not shown), the ambient of a region through which the wafers Wf pass can be isolated from the external ambient and maintained clean. In, addition, it is preferable that the transferring units  1  be connected to a to-be-added single wafer carrying apparatus  20 , for example, in advance. Each transferring unit  1  has a function of reading out an ID (Identification) provided for each wafer Wf in order to identify the wafer Wf. Each transferring unit  1  may be provided with an orientator for aligning a notch or mark of the wafer Wf. The transferring units  1  will be described in detail later. 
   Each of the processing apparatuses  23  to  27  processes the wafers Wf and forms circuits on the wafer Wf. The wafers Wf are carried, for example, wafer-by-wafer between the processing apparatuses  23  to  27  by the single wafer carrying apparatus.  20 . Hereinafter, the method of carrying the carried products such as wafers Wf wafer-by-wafer is referred to as a single wafer carrying method. By carrying the wafers Wf wafer-by-wafer by the single wafer carrying apparatus  20 , a process-waiting time hardly occurs in each of the processing apparatuses  23  to  27 , so that TAT (Turn Around Time) can be reduced. 
   The single wafer carrying apparatus  20  comprises a conveyor  57  for carrying the wafers Wf as the carried products in the R direction in the single wafer carrying manner. The conveyor  57  comprises wafer mounting parts  51 , a guide rail  53  and a driving unit  55 . The wafer mounting parts  51  are supporting means for supporting the wafers Wf. The guide rail  53  is provided along the processing apparatuses  23  to  27  for processing the wafers Wf, as guide means for controlling moving directions of the wafer mounting parts  51 . The driving unit  55  is means for moving the wafer mounting parts  51  along the guide rail  53 . 
     FIG. 2  is a perspective view illustrating an example of the detailed construction of the single wafer carrying apparatuses  20  and  120  and the transferring unit  1  of  FIG. 1 .  FIG. 3  is a block diagram illustrating an example of the electrical construction of the transferring unit  1  of  FIG. 2 . In  FIG. 2 , the processing apparatuses  23  to  27  of  FIG. 1  are omitted. 
   As shown in  FIG. 2 , the transferring unit  1  comprises a case  23  and transferring robots  21  provided on the top of the case  23 . At least one transferring robot  21  is provided. Each of the transferring robots is means for receiving a wafer Wf from the wafer mounting parts  51  of the one single wafer carrying apparatus  20  and handing over the wafer Wf to the wafer mounting parts  51  of the other single wafer carrying apparatus  120 . It is understood that the transferring unit  1  may be constructed to hand over the wafers Wf in the direction from the single wafer carrying apparatus  120  to the single wafer carrying apparatus  20  or in the bi-directions. The transferring unit  1  may be constructed to hand over all or some of the wafers Wf from the one carrying apparatus  20  to the other carrying apparatus  120  by the wafer mounting parts  51 . 
   In addition to the transferring robots  21 , the transferring unit  1  further comprises interfaces  43  and  45  and a synchronization control unit  41 , as shown  FIG. 3 . The interfaces  43  and  45  are means for being electrically connected to other interfaces (not shown) provided to the single wafer carrying apparatuses  20  and  120 , respectively. The interfaces  43  and  45  have a function of exchanging synchronization signals to be synchronized with the driving units  55  of the single wafer carrying apparatuses  20  and  120 , respectively. 
   The interfaces  43  and  45  are electrically connected to the synchronization unit  41 , respectively. The synchronization unit  41  is connected to the transferring robots  21 . The synchronization unit is synchronization control means for synchronizing the driving unit  55  of the one single wafer carrying apparatus  20  with the driving unit  55  of the other added single wafer carrying apparatus  120 . Specifically, the synchronization unit  41  applies driving control signals to the transferring robots  21  while synchronizing the single wafer carrying apparatuses  20  and  120 . 
     FIG. 4  is a perspective view illustrating an example of an external view of the transferring robots  21  of  FIG. 1  or  2 .  FIG. 5  is a perspective view illustrating a state in which the wafer Wf is scooped with a hand  303  shown in  FIG. 4 . 
   Each transferring robot  21  of  FIG. 4  comprises a main body  300 , a first arm  301 , a second arm  302 , and the hand  303 . The first arm  301  is rotatable around a central axis CL of the main body  300 . The second arm  302  is rotatable around a rotary axis CL 1  of the first arm  301 . The hand  303  is rotatable around a rotary axis CL 2  as well as a rotary axis CL 3 . 
   As shown in  FIG. 5 , the hand  303  has almost U-shaped arm portions  305  and  305 . The arm portions  305  and  305  have holding portions  306  for holding an outer circumferential edge surface of a wafer Wf. In addition, each of the transferring robots  21  of  FIG. 4  may have one hand  303  (a single hand), two hands  303  (double hands), or three or more hands  303 . 
   Up to now, the construction including the transferring unit  1  has been described. Next, an example of a state in which the wafers Wf are transferred in case of the single wafer carrying apparatus  120  being added to the single wafer carrying apparatus  20  will be described with reference to  FIGS. 1 to 4 . 
   Firstly, as shown in  FIG. 1 , the semiconductor manufacturing apparatus  100  comprises the single wafer carrying apparatus  20  between the processing apparatuses  23  and  24  and the processing apparatuses  26  and  27 . That is, the single wafer carrying apparatus  20  has a function of carrying the wafers Wf processed by the processing apparatuses  23  to  27  in the single wafer carrying manner in an R direction on the conveyor  57 . 
   The single wafer carrying apparatus  20  is typically an apparatus provided depending on demands for semiconductor devices, for example. In the below description, it is assumed that demands for the semiconductor devices are increased and new processing apparatuses (not shown) and the single wafer carrying apparatus  120  are to be added. Since the to-be-added single wafer carrying apparatus  120  and the existing single wafer carrying apparatus  20  independently have their own single wafer carrying functions, a simple connection therebetween cannot implement continuous single wafer carrying of wafers Wf. 
   Therefore, the transferring unit  1  is provided between the to-be-added single-wafer carrying apparatus  120  and the existing single wafer carrying apparatus  20 , as shown in  FIG. 2 . The transferring unit  1  electrically connects the existing single wafer carrying apparatus  20  and the to-be-added single wafer carrying apparatus  120 , as shown in  FIG. 3 . Accordingly, the transferring unit  1  can control the driving of the transferring robots  21  while synchronizing the single wafer carrying apparatuses  20  and  120  by the synchronization control unit  41 . 
   The transferring robots  21  are arranged, as shown in  FIG. 2 , to receive all the wafers Wf, for example, carried in the R direction by the conveyor  57  in the single wafer carrying apparatus  20  and to hand over all the wafers to the conveyor  57  in the single wafer carrying apparatus  120 . Specifically, as shown in  FIG. 2 , each transferring robot  21  receives the wafer Wf, which is held by the wafer mounting part  51  and carried in the R direction along the guide rail  53  in the single wafer carrying apparatus  20 , by a scooping operation of each hand  303 . 
   The wafers Wf that do not need to be transferred from the single wafer carrying apparatus  20  to the single wafer carrying apparatus  120  in  FIG. 2  may not be scooped by the transferring robots  21  but carried in the single carrying manner in the single wafer carrying apparatus  20 . That is, the transferring robot  21  is constructed to receive some wafers Wf selected among the plurality of wafers Wf carried in the single wafer carrying apparatus  20 . According to the construction, since the wafers Wf which need to be carried only in the single wafer carrying apparatus  20  can not be transferred to the single wafer carrying apparatus  120  by the transferring robots  21 , the wafers Wf can be efficiently carried. 
   Then, the transferring robots  21  hand over the wafers Wf received by the hands  303  to the wafer mounting parts  51  of the single wafer carrying apparatus  120 , while being synchronized with the single wafer carrying apparatus  120 . In the single wafer carrying apparatus  120 , the wafers Wf are held by the wafer mounting parts  51  and carried in the R direction along the guide rail  53  in the single wafer carrying manner by the wafer mounting parts  51 . 
   In addition, in a case where the transferring unit  1  comprises a plurality of transferring robots  21 , one transferring robot  21  may transfer the wafers Wf from the single wafer carrying apparatus  20  to the single wafer carrying apparatus  120  and another transferring robot  21  may transfer the wafers Wf from the single wafer carrying apparatus  120  to the single wafer carrying apparatus  20 . By the operation of the transferring robots  21 , the transferring unit  1  can transfer the wafers Wf between the single wafer carrying apparatuses  20  and  120 . 
   It should be noted that the transferring unit  1  may be provided between the single wafer carrying apparatuses  20  and  120  in place of being provided on at least one side of the connection portion of the single wafer carrying apparatuses  20  and  120 , as shown in  FIG. 6 . Even in the construction, in the transferring unit  1 , it is also possible to carry all or some of the wafers Wf between the single wafer carrying apparatuses  20  and  120  by the similar operation. 
   According to the first embodiment of the present invention, it is possible to easily add the new single wafer carrying apparatus  120  to the existing single wafer carrying apparatus  20 . By means of the transferring unit  1 , the conveyors of the existing single wafer carrying apparatus  20  and the added single wafer carrying apparatus  120  can be used as a single continuous conveyor. According to the first embodiment of the present invention, the single wafer carrying apparatus  120 , if needed, may be connected to the single wafer carrying apparatus  20  by means of the transferring unit  1 , so that there is no need to provide a long conveyor line in an initial stage in consideration of the future extension. Therefore, it is possible to suppress initial investment and remove unnecessary space in a workplace. In addition, at the time of extension, the needed length of conveyor can be extended at the needed time, so that it is possible to suppress investment. Since the conveying line can be constructed by combining the single wafer carrying apparatuses  20  and  120 , it is possible to obtain various layouts freely. 
   According to the first embodiment, since only the necessary wafers Wf are transferred between the single wafer carrying apparatuses  20  and  120 , it is possible to suppress unnecessary carrying between the single wafer carrying apparatuses  20  and  120  in comparison with the case of conveyor lines for the single wafer carrying apparatuses  20  and  120  being provided in advance. Therefore, TAT (Turn Around Time) is reduced, so that the wafers Wf can be efficiently carried. 
   According the first embodiment, at the time of transferring the wafers Wf between the existing single wafer carrying apparatus  20  and the to-be-added single wafer carrying apparatus  120 , one transferring robot  21  can perform the transferring operation while being synchronized with only one of the existing single wafer carrying apparatus  20  and the added single wafer carrying apparatus  120 , so that the control can be easily performed. It should be noted that the transferring unit  1  may be provided between the single wafer carrying apparatuses  20  and  120 , as shown in  FIG. 6 , in place of being provided at the side of the connection portion of the single wafer carrying apparatus  20  and  120 . 
   Second Embodiment 
     FIGS. 7 ,  8  and  9  are perspective views illustrating examples of constructions of a transferring unit  1   a  and the like to which a transferring apparatus of the second embodiment is adapted. 
   Since the same components of the transferring units  1   d ,  1   a  and  1   b  of the second embodiment as those of the transferring unit  1  of the first embodiment shown in  FIGS. 1 to 6  are indicated by the same reference numerals, description will be mainly made on the different points. 
   In order to extend the carrying distance of the wafers Wf, the single wafer carrying apparatus  120  is connected to the single wafer carrying apparatus  20  through the transferring units  1   d ,  1   a  and  1   b  as shown in  FIGS. 7 ,  8 , and  9 , respectively. As a result, the single wafer carrying apparatuses  20  and  120  constitute a substantially-straight continuous conveyor line. 
   In place of the transferring unit  1  shown in  FIG. 1 , the transferring units  1   d ,  1   a  and  1   b  are provided between the processing apparatuses  23  and  24  and the processing apparatuses  26  and  27  of the semiconductor manufacturing apparatus  100 . Characteristically, the transferring units  1   d ,  1   a , and  1   b  of  FIGS. 7 ,  8 , and.  9 , respectively, comprise buffers  61 , which are not provided in the transferring unit  1  of the first embodiment. The transferring unit  1   d  has the same construction as that of the transferring unit  1  of the first embodiment except for the buffer  61  being provided. The buffer  61  has a function of temporarily storing at least one wafer Wf between the existing single wafer carrying apparatus  20  and the newly added single wafer carrying apparatus  120 . 
   At least one buffer  61  may be provided corresponding to the transferring robots  21 , as shown in  FIG. 8 , or a plurality of buffers  61  as shown in  FIG. 9  may be provided so as to make pairs with the transferring robots  21 . By the construction, since the buffer  61  is provided for every transferring robot  21 , the transferring robots  21  can be easily controlled. Alternately, as shown in  FIG. 7 , a buffer  61  can be shared by a plurality of the transferring robots  21  ( 21   a ,  21   b ,  21   c ,  21   d ). By the construction, since the number of the buffers  61  is small, the transferring unit  1  d can be implemented at a low cost. 
   The constructions of the transferring units  1   d ,  1   a , and  1   b  have been described. Next, an example of a state in which the wafers Wf are transferred by the transferring unit  1   d  and the like will be described. Here, the description will be mainly made on the different points from the first embodiment. 
   As shown in  FIG. 7 , each transferring robot  21  receives the wafer Wf, which is held by the wafer mounting part  51  and carried in the R direction along the guide rail  53  in the single wafer carrying apparatus  20 , by the scooping operation of each hand  303 . The wafers Wf that do not need to be transferred from the single wafer carrying apparatus  20  to the single wafer carrying apparatus  120  may not be scooped by the transferring robots  21  but carried in the single carrying manner in the single wafer carrying apparatus  20 . 
   The transferring unit  1   d  of  FIG. 7  immediately stores the wafers Wf received by the transferring robots  21   a  in the buffer  61 . In a case the wafers. Wf is determined to be able to be transferred to the single wafer carrying apparatus  120 , the transferring robots  21   b  hands over the wafers Wf stored in the buffer  61  while being synchronized with the wafer mounting parts  51  of the single wafer carrying apparatus  120 . In the single wafer carrying apparatus  120 , the wafers Wf are held in the wafer mounting parts  51  and, the wafer mounting parts  51  are continuously transferred in the R direction along the guide rail  53 ., In addition, since the same operation is performed in the transferring unit  1   d  of the opposite side, the wafers Wf are handed over from the single wafer carrying apparatus  120  to the single wafer carrying apparatus  20  in the single wafer carrying manner. 
   In such a construction, since it suffices that the transferring robots  21   a  and  21   b  operate in synchronization with the single wafer carrying apparatuses  20  and  120 , respectively, the control can be easily performed. In addition, in such a construction, since the wafers Wf are handed over between the transferring robots  21  through the buffer  61 , the handing-over can be surely performed. 
   Next, examples of states in which the wafers Wf are transferred by the transferring units  1   a  and  1   b  of  FIGS. 8 and 9 , respectively, will be described. In addition, the description will be mainly made on the different points from the first embodiment. 
   As shown in  FIG. 8  or the like, each transferring robot  21  receives the wafer Wf, which is held by the wafer mounting part  51  and carried in the R direction along the guide rail  53  in the single wafer carrying apparatus  20 , by the scooping operation of each hand  303  of the transferring robot  21 . The wafers Wf that do not need to be transferred from the single wafer carrying apparatus  20  to the single wafer carrying apparatus  120  may not be scooped by the transferring robots  21  but carried in the single carrying manner in the single wafer carrying apparatus  20 . 
   The transferring unit  1   a  and the like determine whether the wafer Wf received by the transferring robot  21  can be immediately transferred, to the single wafer carrying apparatus  120 . In case of the wafer being able to be immediately transferred, the transferring robot  21  hands over the wafer Wf received by the hand  303  to the wafer mounting ports  51  of the single wafer carrying apparatus  120  while being synchronized therewith. In the single wafer carrying apparatus  120 , the wafers Wf are held in the wafer mounting parts  51 , and the wafer mounting parts  51  are continuously carried in the R direction along the guide rail  53  in the single wafer carrying manner. 
   In case of the wafers not being able to be immediately transferred, the following operations are performed. For example, in a case that there is no empty loading space in the wafer mounting parts  51  in the single wafer carrying apparatus  120 , the transferring unit  1   a  and the like store the wafer Wf in the buffers  61  which are provided for the transferring unit  1   a  and the like. The case where wafers Wf cannot be immediately transferred includes a case that the wafers Wf can be mounted on the wafer mounting parts  51  in the single wafer carrying apparatus  120  but cannot be received by the processing apparatuses  23  and the like which are disposed along the single wafer carrying apparatus  120  and to which the wafers Wf are directed. Also in this case, the wafers Wf are stored in the buffer  61 . 
   The transferring robot  21  hands over the wafers Wf stored in the buffer  61  while being synchronized with the wafer mounting parts  51  in the single wafer carrying apparatus  120 . In the single wafer carrying apparatus  120 , the wafers Wf are held in the wafer mounting parts  51 , and the wafer mounting parts  51  are carried in the R direction along the guide rail  53  in the single wafer carrying manner. 
   In addition, a plurality of buffers, for example, two buffers  61  as shown in  FIG. 8 , may be provided on the same plane or in a stacked construction. The buffers  61  may be provided at the outsides of the transferring robot  21  as shown in  FIG. 8  or between the two transferring robots  21  although not shown. In this construction, the two transferring robots  21  may share the buffer  61 . 
   According to the second embodiment of the present invention, in addition to obtaining almost the same effects of the first embodiment, since the single wafer carrying is available within the respective conveyors  57  of the single wafer carrying apparatuses  20  and  120  shown in  FIG. 7  and the like, it is possible to carry the wafers Wf to the suitable carrying distances. That is, according to the needed processes, when the wafers Wf need to be carried only by the single wafer carrying apparatus  20  in the single wafer carrying manner, the single wafer carrying can be performed only in the single wafer carrying apparatus  20  without handing over the wafers to the single wafer carrying apparatus  120 . Since the single wafer carrying apparatus  20  and the like can change the carrying distance according to the needed carrying ability, it is possible to suppress unnecessary carrying of the wafer Wf. As a result, the semiconductor manufacturing apparatus  100  can efficiently manufacture the wafers Wf by improving the TAT (Turn Around Time) in comparison with the conventional one. 
   Third Embodiment 
     FIGS. 10 and 11  are perspective views illustrating examples of constructions of a transferring unit  1   c  and the like to which a transferring apparatus of the third embodiment is adapted. 
   Since the same components of the transferring unit  1   c  of the third embodiment as those of the transferring units  1  ( 1   d ,  1   a  and  1   b ) of the first (second) embodiment shown in  FIGS. 1 to 4  ( FIGS. 7 to 9 ) are indicated by the same reference numerals, description will be mainly made on the different points. It should be noted that the transferring units  1   c  may not comprise the buffer  61  as in the first embodiment. 
   Instead of the transferring units  1  of  FIG. 1  or the like being provided, the transferring unit  1   c  is integrated with the end portion of the single wafer carrying apparatus  20 . Specifically, the transferring unit  1   c  is characterized in that the single wafer carrying apparatus  20  is provided with the transferring unit  1   c  corresponding to the transferring units  1  ( 1   d ,  1   a  and  1   b ) of the first (second) embodiment in advance. That is, a single wafer carrying apparatus  220  is constructed by integrating the transferring unit  1   c  to the single wafer carrying apparatus  20 . In addition, similarly, the transferring unit  1   c  may be also integrated with the single wafer carrying apparatus  120 . 
   The single wafer carrying apparatus  220  has the above construction. Next, an example of a state in which the wafers Wf are transferred by the transferring unit  1   c  will be described. Herein, the description will be mainly made on the different points from the first and second embodiments. 
   In order to extend the carrying distance of the wafers Wf, as shown in  FIG. 11 , the single wafer carrying apparatus  120  is connected to the transferring unit  1   c  provided at an end portion of the single wafer carrying apparatus  220 , as shown in  FIG. 10 . As a result, the single wafer carrying apparatuses  220  and  120  constitute a substantially-straight continuous conveyor line. 
   As shown in  FIG. 10 , each transferring robot  21  receives the wafer Wf, which is held by the wafer mounting part  51  and carried in the R direction along the guide rail  53  in the single wafer carrying apparatus  220 , by the scooping operation of each hand  303  of the transferring robot  21 . The wafers Wf that do not need to be transferred from the single wafer carrying apparatus  220  to the single wafer carrying apparatus  120  may not be scooped by the transferring robots  21  but carried in the single carrying manner in the single wafer carrying apparatus  220 . 
   The transferring unit  1   c  determines whether the wafers Wf received by the transferring robots  21  can be immediately transferred to the single wafer carrying apparatus  120 . In case of the wafers being able to be immediately transferred, the transferring robot  21  hands over the wafers Wf received by the hands  303  to the wafer mounting parts  51  of the single wafer carrying apparatus  120  while being synchronized therewith. In the single wafer carrying apparatus  120 , the wafers Wf are held in the wafer mounting parts  51 , and the wafer mounting parts  51  are continuously carried in the R direction along the guide rail  53  in the single wafer carrying manner. 
   In case of the wafers not being able to be immediately transferred, the following operations are performed. For example, in a case that there is no empty loading space in the wafer mounting parts  51  in the single wafer carrying apparatus  120 , the transferring unit  1   c  stores the wafers Wf in the buffers  61  which are provided for the transferring unit  1   a Another case of the wafers incapable of being transferred, for example, is the case that the wafers Wf can be mounted on the wafer mounting parts  51  in the single wafer carrying apparatus  120  but can not be received by the processing apparatuses  23  and the like which are disposed along the single wafer carrying apparatus  120  and to which the wafers Wf are directed. Also in this case, the wafers Wf are stored in the buffer  61 . 
   The transferring robot  21  hands over the wafers Wf stored in the buffer  61  to the wafer mounting parts  51  in the single wafer carrying apparatus  120  while being synchronized therewith. In the single wafer carrying apparatus  120 , the wafers Wf are held in the wafer mounting parts  51 , and the wafer mounting parts  51  are carried in the R direction along the guide rail  53  in the single wafer carrying manner. 
   It should be noted that a plurality of buffers, for example, the two buffers  61  as shown in  FIG. 8 , may be provided on the same plane or in a stacked construction. The buffers  61  may be provided at the outsides of the transferring robot  21  as shown in  FIG. 8  or between the two transferring robots  21  although not shown. In this construction, the two transferring robots  21  may share the buffer  61 . 
   According to the third embodiment of the present invention, in addition to obtaining almost the same effects of the first and second embodiments, it suffices that a new single wafer carrying apparatus  120  is newly added to the existing single wafer carrying apparatus  220  in case of adding the single wafer carrying apparatus  220  in order to increase the ability of carrying wafer Wf. That is, the single wafer carrying apparatus  220  is provided with the transferring unit  1   c  in advance, it suffices that the single wafer carrying apparatus  120  is installed so as to be connected to the single wafer carrying apparatus  220  through the transferring unit  1   c . As a result, the single wafer carrying apparatus  220  and the like can change the carrying distance according to the needed carrying ability, and it is possible to suppress unnecessary carrying of the wafer Wf. 
   Fourth Embodiment 
     FIG. 12  is a perspective view illustrating an example of the construction of the transferring unit  1   e  to which a transferring apparatus of the fourth embodiment is adapted. 
     FIG. 13  is a perspective illustrating an example of a state in which a cover  256  is removed from the transferring unit  1   e  of  FIG. 12  and the up-down moving mechanism thereof is exposed.  FIG. 14  is a perspective view illustrating an example of a detailed construction of the up-down moving mechanism of each transferring unit  1   e  of  FIG. 13 . 
   Since the same components of the transferring units  1   e  of the fourth embodiment shown in  FIG. 12  as those of the transferring units  1  of the first embodiment shown in  FIGS. 1 to 6  are indicated by the same reference numerals, description will be mainly made on the different points. 
   Instead of the transferring units  1  of  FIG. 1  or the like, the transferring unit  1   e  is provided near a connection portion of the single wafer carrying apparatus  20  and  120 , for example, on both sides of the connection portion. The transferring unit  1   e  of  FIG. 12  may be constructed to be separated from the single wafer carrying apparatus  20  or to be integrated with the single wafer carrying apparatus  20 . 
   Each of the single wafer carrying apparatuses  20  and  120  and the transferring units  1   e  comprises a cover and a cleaning device (not shown), so that the ambient of a region through which the wafers Wf pass can be isolated form the external ambient and maintained clean. 
   In order to extend the carrying distance of the wafers Wf, the single wafer carrying apparatus  20  is connected to the single wafer carrying apparatus  120  through the transferring unit  1   e , as shown in the figure. As a result, the single wafer carrying apparatuses  20  and  120  constitute a substantially-straight continuous conveyor line. 
   Each of the transferring units  1   e  comprises a transferring hand portion  400  having a plurality of transferring hands  401 ,  402 , and  403 . Although there are three hands in the embodiment, two or less hands or four or more hands are available. One wafer Wf can be mounted on the respective transferring hands  401 ,  402 , and  403 . 
   Each of the transferring hands  401 ,  402 , and  403  are adapted to move, for example, simultaneously in up-down directions Z 1  and Z 2  and horizontal directions X 1  and X 2 . The construction by which the transferring hands  401 ,  402 , and  403  are moved in the up-down directions Z 1  and Z 2  is as shown in  FIG. 13 .  FIG. 13  illustrates an example of the state in which the covers  256  provided in  FIG. 12  are removed from the transferring units  1   e.    
     FIG. 14  illustrates an enlarged view of the up-down moving mechanism and the horizontal moving mechanism shown in  FIG. 12 . Although all the transferring hands  401 ,  402 , and  403  are illustrated in  FIGS. 12 and 13 , only the transferring hand  401 , as an example, is illustrated in  FIG. 14  for simplification. The transferring hand portion  400  having one transferring hand  401  comprises a guide  267  and a cylinder  266  as the up-down moving mechanism and a shaft  269  and actuator  268  as the horizontal moving mechanism, as shown in the figure. 
   The actuator  268  has a function of rotating the shaft  269  the shaft  269  is a shaft extending along the horizontal directions X 1  and X 2  has a construction of moving the transferring hand portion  400  along the horizontal directions X 1  and X 2  by the operation of the actuator  268 . Incidentally, the, up-down moving mechanism may be a cam mechanism using a motor. In addition, in case of the plurality of the transferring hands  401 ,  402 , and  403  being provided, it is preferable that the up-down moving mechanism has a construction of moving the plurality of the transferring hands as a group in the horizontal directions, as shown in  FIGS. 12 and 13 . 
   The guide  267  of  FIG. 14  is a member being extended in the vertical directions Z 1  and Z 2 . The cylinder  266  has a construction of moving the transferring hand  401  in the vertical directions Z 1  and Z 2  along the guide portion  267  by the operation thereof. Incidentally, the up-down moving mechanism may be a cam mechanism using a motor. In addition, in case of the plurality of the transferring hands  401 ,  402 , and  403  being provided, it is preferable that the up-down moving mechanism has a construction of moving the plurality of the transferring hands as a group in the up-down directions, as shown in  FIGS. 12 and 13 . 
   By moving the transferring hand portion  400  in the up-down and horizontal directions with the aforementioned constructions in accordance with the moving of the single wafer carrying apparatuses  20  and  120 , the wafers Wf are transferred from the one single wafer carrying apparatus to the other single wafer carrying apparatus. In addition, in case that each transferring unit  1   e  comprises two or more hands, for example, it is necessary to provide (transferring hand number-1) of intermediate stages  404  and  405 , which are used to temporarily load the wafers Wf at the time of transferring. Herein, since there are three transferring hands  401 ,  402 , and  403 , two intermediate stages  404  and  405  are provided. 
   A detailed construction example of the transferring units  1   e  has been described. Next, an example of a state in which the wafers Wf is transferred will be described. 
   As shown in  FIG. 12 , the wafers Wf are held in the wafer mounting parts  51  which are carried in the R direction along the guide rail  53  in the single wafer carrying apparatus  20 . 
   Firstly, the transferring hand portion  400  of the transferring unit  1   e  stands by at a predetermined receiving position. At the same time that the wafer mounting part  51  is passing through the predetermined receiving position as shown in  FIG. 15 , the wafer Wf are scooped in the up direction Z 1  from the bottom and received by the transferring hand  401  in accordance with the moving the conveyor  57  of the single wafer carrying apparatus  20 , as shown in  FIG. 16 . At this time, the wafers Wf disposed on the intermediate stages  404  and  405  are also scooped by the transferring hands  402  and  403 , respectively. 
   In the state that each of the wafers Wf is scooped, as shown in  FIG. 17 , the transferring hand portion  400  moves in the horizontal direction X 2  as shown in  FIG. 16  to arrive at the predetermined hand-over position as shown in  FIG. 18 . At the time that the wafer mounting parts  51  on the single wafer carrying conveyor  120  are passing through the predetermined hand-over positions, the transferring hand portion  400  hands over the wafers Wf to the intermediate stage  404  as shown in  FIG. 19  in accordance with the moving of the conveyor  57  of the single wafer carrying apparatus  120 . 
   At the same time, if another transferring hand portion  400  holds a wafer Wf, the transferring hand portion  400  hands over the wafer Wf to the wafer mounting parts  51  on the conveyor  57 . Simultaneously, the wafer Wf on the intermediate stage  404 , the wafer Wf temporarily mounted on the intermediate stage  405 , and the wafer Wf scooped from the single wafer carrying apparatus  20  are transferred to the wafer mounting parts  51  on the single wafer carrying apparatus  120 , the intermediate stage  405 , and the intermediate stage  404 , respectively. 
   The transferring hand portion  400  having handed over the wafer Wf immediately moves along the horizontal direction X 1  to the receiving position and stands by. In the single wafer carrying apparatus  120 , the wafers Wf are held on the wafer mounting parts  51 , and the wafer mounting parts  51  are carried in the R direction along the guide rail  53  in a single wafer carrying manner. This is one cycle of the operation. This operation is performed irrespective of the presence or absence of a wafer on the wafer mounting parts  51  of the single wafer carrying apparatus  20 . 
   By the repetition of this operation, all the wafers Wf carried by the single wafer carrying apparatus  20  are transferred to the single wafer carrying apparatus  120 . The transferring unit  1   e  provided at the opposite of the single wafer carrying apparatus performs almost the same operation except that the carrying direction is reverse, and all the wafer Wf carried by the single wafer carrying apparatus  120  are transferred to the single wafer carrying apparatus  20 . 
   It should be noted that in the fourth embodiment, the transferring unit may have no intermediate stage similar to the transferring unit if shown in  FIG. 20 . The transferring unit  1   f  has almost the same construction as that of the aforementioned transferring units  1   e  except for the following points. The transferring unit if is different from the aforementioned transferring units  1   e  and the like in that the wafers Wf are carried between the wafer mounting parts  51  and  51  of the single wafer carrying apparatuses  20  and  120  by the only the transfer hand portions  400 , instead of the wafers Wf being carried through the intermediate stages by the transferring hand portions  400 . According to the construction, since the intermediate stages are not necessary, cost can be further suppressed in comparison with the transferring unit  1   e  having the construction as shown in  FIG. 12 . 
   As such, according to the fourth embodiment of the present invention, since the transferring hand portions  400  can transfer all the wafers, without changing the order, from the one single wafer carrying apparatus  20  to the other single wafer carrying apparatus  120 , and even in the state that the conveyors  57  are connected to each other, they can be used as if they were one single wafer carrying apparatus. 
   In addition, according to the fourth embodiment of the present invention, since the transferring unit  1   e  is used, the single wafer carrying apparatus can be provided in accordance with production ability. Therefore, suitable investment is available and freedom of layout is improved, so that almost the same effects as those of the first embodiment can be obtained. Furthermore, in the fourth embodiment, since all the wafers Wf are transferred, the timing for dispatching the wafers Wf between the single wafer carrying apparatuses  20  and  120  and the transferring hand portions  400  or the control of the empty states of the wafer mounting parts  51  on the single wafer carrying apparatuses  20  and  120  is not necessary in comparison with the first to third embodiments. Therefore, the control can be easily performed. 
   The present invention is not limited to the above embodiments, and various modifications may be made thereto without departing from the appended claims. For example, respective constructions of the above embodiments may be changed by arbitrarily omitting or combining some portion thereof unlike the above descriptions. In addition, in the above embodiments, the semiconductor wafer is used as an example of a substrate wafer as a carried product. However, the carried product is not so limited, and the embodiments can be adapted to other types of substrate wafers. In addition, instead of the substrate wafers, the above embodiments can be adapted to an electronic device manufacturing substrate as a carried product. The electronic device manufacturing substrate may include, for example, a substrate for manufacturing a liquid crystal display device or a quartz device.