Patent Publication Number: US-2004043513-A1

Title: Method of transferring processed body and processing system for processed body

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Technical Field  
       [0002] The present invention relates generally to a transfer method and processing system for a processing object, such as a semiconductor wafer, to which a predetermined processing is carried out.  
       [0003] 2. Background Art  
       [0004] In a typical system for producing a semiconductor device, various processing devices are combined, and a transfer mechanism is provided for automatically delivering a wafer between these processing devices and between the processing devices and a cassette which houses therein a large number of semiconductor wafers. This transfer mechanism has a transfer arm portion which is capable of bending and stretching, swiveling and vertically moving. The transfer mechanism is designed to horizontally move the transfer arm portion to a transfer position to transfer the wafers to a predetermined position.  
       [0005] In this case, it is not only required to prevent the transfer arm from interfering or colliding with another member while the transfer arm portion is operated, but it is also required to appropriately hold a wafer, which is located at a certain place, to transfer the wafer to a target position to accurately deliver the wafer to an appropriate place within a dislocation quantity of, e.g. ±0.1 mm. Therefore, a so-called teaching operation is carried out for causing a control part, such as a computer, which controls the operation of the transfer arm portion, to store an important position, such as a place to which a wafer is transferred on a transfer path of the transfer arm portion. The teaching method of this type is disclosed in, e.g. Japanese Patent Laid-Open Nos. 7-193112, 9-252039 and 2000-127069.  
       [0006] Recently, a transfer mechanism having two transfer arm portions is often used so as to be capable of holding a plurality of, e.g. two, semiconductor wafers, at a time in order to enhance the efficiency of transfer of semiconductor wafers. The transfer mechanism of this type has two transfer arm portions which are capable of, e.g. bending and stretching and extending on the same horizontal plane in the opposite directions and swiveling and so forth. When a semiconductor wafer is transferred, the transfer mechanism is designed to cause a transfer arm portion, which is nearer to the wafer to be transferred, to hold and transfer the wafer, to shorten the time required to transfer the wafer, to improve throughput.  
       [0007] By the way, in the above described transfer mechanism, there are some cases where the whole transfer mechanism rotates while both of the transfer arm portions horizontally hold the wafer, respectively. Therefore, there is a problem in that the whole system for housing therein the whole transfer mechanism is very large in order to ensure a space required to carry out rotation and so forth. In particular, since a wafer which will be the main-current wafer in future has a diameter of 300 mm, it is required to provide a space having a diameter of about 1 m in order to rotate the transfer mechanism while the wafers are arranged on the same horizontal plane, so that it is not possible to avoid the enlargement of the size of the system.  
       [0008] Moreover, as described above, since the transferred position of the wafer must be accurately positioned when the wafer is transferred into a processing device, the transferred position must be taught to both transfer arms with a very high accuracy when a so-called teaching for teaching the transferred position to both transfer arm portions is carried out, so that there is a problem in that it is a lot of time to carry out the teaching.  
       DISCLOSURE OF THE INVENTION  
       [0009] The present invention has been made in order to effectively solve the above described problems. It is an object of the present invention to a method for transferring a processing object, which is miniaturized to have a small occupying area and which can carry out a teaching operation in a short time, and a system for processing a processing object, the system having a transfer mechanism.  
       [0010] According to a first aspect of the present invention, there is provided a method for transferring a processing object in a processing system for processing the processing object, the processing system comprising a positioning system for positioning the processing object, a processing device for carrying out a predetermined processing to the processing object, and a transfer mechanism having upper and lower transfer arms which are arranged in upper and lower stages and which are capable of being separately controlled to transfer the processing object to the processing device, wherein only the upper transfer arm is used when an unprocessed object positioned by the positioning system is transferred to the processing device, and only the lower transfer arm is used when a processed object in the processing device is transferred.  
       [0011] According to the present invention, only the upper transfer arm is used when the object positioned by the positioning system is transferred to the processing device, and only the lower transfer arm is used when the processed object in the processing device is transferred, so that it is possible to prevent particles, which are produced from the processed object held by the lower transfer arm, from adhering to the unprocessed object held by the upper transfer arm.  
       [0012] According to a second aspect of the present invention, there is provided a method for transferring a processing object in a processing system for processing the processing object, the processing system comprising a positioning system for positioning the processing object, a processing device for carrying out a predetermined processing to the processing object, and a transfer mechanism having upper and lower transfer arms which are arranged in upper and lower stages and which are capable of being separately controlled to transfer the processing object to the processing device, the method comprising the steps of: transferring an unprocessed object, which is positioned by the positioning system, to the processing device by means of the upper transfer arm of the transfer mechanism; and receiving a processed object, which is processed by the processing device, by means of the lower transfer arm, and delivering the unprocessed object, which is positioned to be held by the upper transfer arm, to the processing device.  
       [0013] According to the present invention, it is possible to transfer the object to the processing device without allowing particles, which are produced from the processed object, to adhere to the object positioned by the positioning system, and it is possible to effectively and smoothly receive the processed object from the processing device and deliver the positioned and unprocessed object to the processing device.  
       [0014] In the first and second aspects of the present invention, the method may comprise a step of previously holding an unprocessed object, which is not positioned, by the lower transfer arm when a positioned object, which is mounted on the positioning system, is replaced with the unprocessed object to be transferred, and transferring the unprocessed object, which is held by the lower transfer arm, to the positioning system after the positioned object is received by the upper transfer arm.  
       [0015] If the lower and upper transfer arms are thus used, it is possible to transfer the unprocessed object, which is not positioned, to the positioning system, and it is possible to receive the positioned object by the upper transfer arm to transfer the object to the processing device, so that it is possible to smoothly position the unprocessed object, which is not positioned, in the positioning system.  
       [0016] In the first and second aspects of the present invention, the transfer precision of the upper transfer arm may be more accurately adjusted than the transfer precision of the lower transfer arm when a predetermined motion of the transfer mechanism is taught.  
       [0017] Thus, the position precision may be low when the teaching operation for the lower transfer arm is carried out if the position is accurately adjusted when the teaching operation for the upper transfer arm is carried out, so that it is possible to rapidly and simply carry out the teaching operation.  
       [0018] According to a third aspect of the present invention, there is provided a method for transferring a processing object in a processing system for processing the processing object, the processing system comprising a processing device for carrying out a predetermined processing to the processing object, and a transfer mechanism having upper and lower transfer arms which are arranged in upper and lower stages and which are capable of being separately controlled to transfer the processing object to the processing device, wherein only the lower transfer arm is used when a processed object is received from the processing device, and only the upper transfer arm is used when an unprocessed object is delivered to the processing device.  
       [0019] According to the present invention, in the processing system regardless of the presence of a positioning system, only the upper transfer arm is used when the unprocessed object is transferred to the processing device, and only the lower transfer arm is used when the processed object in the processing device is transferred, so that it is possible to prevent particles, which are produced from the processed object held by the lower transfer arm, from adhering to the unprocessed object held by the upper transfer arm.  
       [0020] According to a fourth aspect of the present invention, there is provided a method for transferring a processing object in a processing system for processing the processing object, the processing system comprising a processing device for carrying out a predetermined processing to the processing object, and a transfer mechanism having upper and lower transfer arms which are arranged in upper and lower stages and which are capable of being separately controlled to transfer the processing object to the processing device, wherein only the lower transfer arm is used when a processed object is received from the processing device, and only the upper transfer arm is used when an unprocessed object is delivered to the processing device.  
       [0021] According to the present invention, the transfer arms of the transfer mechanism are arranged in the upper and lower two stages, so that the transfer mechanism itself can be miniaturized to greatly decrease the space occupied by the transfer mechanism. In addition, only the upper transfer arm is used when the object positioned by the positioning system is transferred to the processing device, and only the lower transfer arm is used when the processed object in the processing device is transferred, so that it is possible to prevent particles, which are produced from the processed object held by the lower transfer arm, from adhering to the unprocessed object held by the upper transfer arm.  
       [0022] The transfer precision of the upper transfer arm may be more accurately adjusted than the transfer precision of the lower transfer arm.  
       [0023] Thus, the position precision may be low when the teaching operation for the lower transfer arm is carried out if the position is accurately adjusted when the teaching operation for the upper transfer arm is carried out, so that it is possible to rapidly and simply carry out the teaching operation.  
       [0024] According to a fifth aspect of the present invention, there is provided a processing system comprising: a processing device for carrying out a predetermined processing to the processing object; and a transfer mechanism for transferring the processing object to the processing device, the transfer mechanism including: upper and lower transfer arms which are arranged in upper and lower stages and which are capable of being separately controlled to transfer the processing object, and a control part for causing only the lower transfer arm to be used when a processed object in the processing device is received, and for causing only the upper transfer arm to be used when an unprocessed object is delivered to the processing device.  
       [0025] According to the present invention, in the processing system regardless of the presence of a positioning system, the transfer arms of the transfer mechanism are arranged in the upper and lower two stages, so that the transfer mechanism itself can be miniaturized to greatly decrease the space occupied by the whole mechanism. In addition, only the upper transfer arm is used when the unprocessed object is transferred to the processing device, and only the lower transfer arm is used when the processed object in the processing device is transferred, so that it is possible to prevent particles, which are produced from the processed object held by the lower transfer arm, from adhering to the unprocessed object held by the upper transfer arm. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0026]FIG. 1 is a schematic diagram showing a processing system for processing a processing object according to the present invention;  
     [0027]FIG. 2 is a side view showing a positioning system;  
     [0028]FIG. 3 is a plan view showing a state that a transferring object is mounted on a positioning system;  
     [0029]FIG. 4 is a perspective view showing a transfer mechanism;  
     [0030]FIG. 5 is a flow chart showing a method for transferring a wafer which is a processing object when an actual process is carried out; and  
     [0031]FIG. 6 is a schematic diagram showing another example of a processing system for processing a processing object according to the present invention. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION  
     [0032] Referring to the accompanying drawings, a preferred embodiment of a system for processing a processing object and a method for transferring a processing object according to the present invention will be described below in detail.  
     [0033]FIG. 1 is a schematic diagram showing a processing system for processing a processing object according to the present invention, FIG. 2 is a side view showing a positioning system, FIG. 3 is a plan view showing a state that a transferring object is mounted on a positioning system, and FIG. 4 is a perspective view showing a transfer mechanism. A case where a semiconductor wafer is used as a processing object will be described below.  
     [0034] First, referring to FIG. 1, a processing system for processing a processing object will be described. This processing system  2  generally comprises a processing unit  4  for carrying out various processes, such as deposition and etching, to a semiconductor wafer W serving as a processing object, and a transfer unit  6  for carrying the wafer W in and out of the processing unit  4 . The transfer unit  6  has a common transfer chamber  8  shared when the wafer W is transferred.  
     [0035] The processing unit  4  has one or a plurality of, e.g. two, processing devices  12 A and  12 B in the shown embodiment, and load-lock chambers  10 A and  10 B which are communicated with the respective processing devices and which can be evacuated. The processing unit  4  is designed to carry out the same kind of processes or different kinds of processes to the wafer W in the respective processing devices  12 A and  12 B. In the processing devices  12 A and  12 B, supporting tables  14 A and  14 B for supporting thereon the wafer W are provided, respectively.  
     [0036] On the other hand, the common transfer chamber  8  of the transfer unit  6  comprise a laterally enlarged box in which an inert gas, such as N 2  gas, and clean air circulate. On one side of the laterally enlarged box, one or a plurality of, e.g. three, cassette tables  16 A,  16 B and  16 C for supporting thereon three cassette vessels are provided in the shown embodiment. On each of the cassette tables, the cassette vessels  18 A through  18 C can be mounted one by one. Each of the cassette vessels  18 A through  18 C can house therein, e.g. twenty five wafers W at the maximum, in multistage at regular intervals, and is filled with, e.g. N 2  gas, to be closed. The wafer can be carried in and out of the common transfer chamber  8  via gate valves  19 A through  19 C.  
     [0037] In the common transfer chamber  8 , there is provided a transfer mechanism  20  which transfers the wafer W in longitudinal directions and which is a feature of the present invention. The transfer mechanism  20  is slidably supported on a guide rail  22  which extends in longitudinal directions in the central portion of the common transfer chamber  8 . The guide rail  22  is provided with a moving mechanism, e.g. a ball screw  26 . This ball screw  26  engages a screw hole (not shown) of a base  28  of the transfer mechanism  20 . Therefore, if a drive motor  30  having the ball screw  26  at its end is rotated, the transfer mechanism  20  moves in X direction along the guide rail  22 . Furthermore, a linear motor serving as a moving mechanism may be used for moving the base  28  on the guide rail  20 .  
     [0038] The other end of the common transfer chamber  8  is provided with an orienter  32  serving as a positioning system for positioning the wafer. In the middle of the common transfer chamber  8  in longitudinal directions, the two load-lock chambers  10 A and  10 B capable of being evaluated for connecting the two processing devices  12 A and  12 B are provided via gate valves  34 A and  34 B, respectively. In each of the load-lock chambers  10 A and  10 B, there are provided a pair of buffer supporting tables  36 A,  36 B and  38 A,  38 B for temporarily supporting the wafer W to allow the wafer W to stand by. It is assumed that the buffer supporting tables  36 A and  38 A on the side of the common transfer chamber  8  are first buffer supporting tables, and the buffer supporting tables  36 B and  38 B on the opposite side are second buffer supporting tables. Between the buffer supporting tables  36 A and  36 B and between the buffer supporting tables  38 A and  38 B, there are provided separate transfer mechanisms  40 A and  40 B, each of which comprises an articulated arm capable of bending and stretching, swiveling and vertically moving. The tip ends of the separate transfer mechanisms  40 A and  40 B are provided with forks  41 A and  41 B at their tips for delivering the wafer W between the first and second buffer supporting tables  36 A,  36 B and  38 A,  38 B. The other ends of the load-lock chambers  10 A and  10 B are connected to the processing devices  12 A and  12 B via gate valves  42 A and  42 B capable of being open and closed, respectively. Furthermore, the wafer is carried in and out of the processing devices  12 A and  12 B by means of the separate transfer mechanisms  40 A and  40 B which are provided so as to correspond thereto, respectively.  
     [0039] Also as shown in FIGS. 2 and 3, the orienter  32  has a reference table  52  which is rotated by a drive motor  50 . The orienter  32  is designed to rotate while the wafer W is supported on the reference table  52 . On the outer periphery of the reference table  52 , an optical sensor  64  for detecting the peripheral portion of the wafer W is provided. The optical sensor  64  comprises a linear light emitting element  64 A having a predetermined length arranged so as to extend in radial directions, and a light receiving element  64 B arranged so as to correspond thereto via the peripheral portion of the wafer. The optical sensor  64  is designed to cause the end portion of the wafer to be irradiated with curtain-like laser light L to detect the variation therein. A detection operating part  66  can recognize an eccentric quantity and eccentric direction of the wafer W, and the rotational position, i.e. orientation, of a cut-out mark, e.g. a notch  68 , formed in the wafer W.  
     [0040] In FIG. 3, O 1  denotes the center (rotation center) of the reference table  52 , and O 2  denotes the center of the wafer W. Therefore, the eccentric quantity is Ar. Furthermore, the cut-out mark is the notch  68  in the case of a 300 mm wafer, and is a notch or orientation flat in the case of 8 inch or 6 inch wafer.  
     [0041] Also as shown in FIG. 4, the transfer mechanism  20  has two articulated transfer arms  70  and  72  which are arranged in upper and lower two stages. The tip ends of the transfer arms  70  and  72  are provided with two-way forks  70 A and  72 A, respectively. The forks  70 A and  72 A are designed to directly hold the wafer W, respectively. Therefore, each of the transfer arms  70  and  72  is designed to bend and stretch in R directions which are radial directions from its center. The bending and stretching motions of the transfer arms  70  and  72  are capable of being separately controlled.  
     [0042] The rotation shafts  74  and  76  of the transfer arms  70  and  72  are coaxially and rotatably connected to the base  28 , respectively, so as to be capable of integrally rotating in θ directions which are swivel directions with respect to, e.g. the base  28 . Moreover, the rotation shafts  74  and  76  are also capable of, e.g. integrally moving in vertical directions, i.e. Z directions, about the base  28 . Therefore, all of position coordinates are expressed as coordinates of X, Z, R and θ. Of course, the coordinates of the respective shafts can recognize a displacement quantity from a preset reference point by, e.g. an encoder.  
     [0043] The transfer mechanism  20  should not be limited to the structure shown in FIG. 4 if it can be provided with the transfer arms  70  and  72  in upper and lower two stages. Referring to FIG. 1 again, in order to control the operation of the whole processing system including the positioning operations of the transfer mechanism  20  and transfer mechanisms  40 A and  40 B, a control part  80  comprising, e.g. a microcomputer, is provided. The control part  80  stores therein position coordinates and so forth which are required during a positioning teaching operation which will be described later.  
     [0044] Also referring to FIG. 5, a transferring method according to the present invention carried out by the above described processing system  2  will be described below.  
     [0045]FIG. 5 is a flow chart showing a method for transferring a wafer W when an actual process is carried out.  
     [0046] First, before a semiconductor wafer W is actually processed, a teaching operation is carried out so that the transfer mechanism  20  can accurately transfer the wafer W to a correct position when the transfer mechanism  20  transfer the wafer W. In this case, according to the present invention, when the wafer W positioned by the orienter  32  is transferred to the load-lock chamber  10 A or  10 B, the upper-stage transfer arm  70  of the two transfer arms  70  and  72  is always used in order to prevent particles from adhering thereto, so that a teaching operation for accurately positioning only the upper-stage transfer arm  70  is previously carried out. As is well known, this teaching operation is carried out by accurately and manually arranging, e.g. the wafer W, on the fork  70 A of the transfer arm  70  at an appropriate position, accurately and manually arranging the transfer arm  70  on the first buffer supporting table  36 A of the load-lock chamber  10 A at an appropriate position, and causing the control part  80  to describe coordinates at this time. In fact, such an operation is repeated a plurality of times to take mean coordinates. Such a teaching operation with a high positional precision is also carried out with respect to the first buffer supporting table  38 A of the other load-lock chamber  10 B.  
     [0047] According to the present invention, such a teaching operation with a high positional precision may be carried out with respect to only the upper-stage transfer arm  70  without being carried out with respect to the lower-stage transfer arm  72  which does not transfer the wafer from the orienter  32 , and a teaching operation with a low positional precision may be simply carried out with respect to the lower-stage transfer arm  72  to such an extent that the wafer does not interfere with other members.  
     [0048] An actual transfer method, which is carried out when a semiconductor wafer is processed, will be described below.  
     [0049] It is assumed that the transferred semiconductor wafer has been positioned by the orienter  32  and also has been processed in the processing device.  
     [0050] First, an unprocessed semiconductor wafer W is picked up from a cassette vessel on one of the three cassette tables, e.g. the cassette vessel  18 C on the cassette table  16 C, and held by the fork  72 A by driving the lower-stage transfer arm  72  of the transfer mechanism  20  (S 1 ), and the wafer W is transferred to the orienter  32  by moving the transfer mechanism  20  in X direction (S 2 ).  
     [0051] Then, the unprocessed semiconductor wafer W on the rotating table  52 , which has been transferred and positioned by the orienter  32 , is picked up and held by the fork  70 A by driving the upper-stage empty transfer arm  70 , the transfer precision of which has been accurately adjusted (S 3 ). Thus, the rotating table  62  is emptied.  
     [0052] Then, the unprocessed wafer held by the fork  72 A of the transfer arm  72  is mounted on the empty rotating table  52  (S 4 ). Furthermore, this wafer is positioned before the next unprocessed wafer is transferred.  
     [0053] Then, the unprocessed wafer held by the upper-stage transfer arm  70  as described above is moved to a desired processing device of the two processing devices  12 A and  12 B, e.g. the load-lock chamber  10 A of the processing device  12 A, by moving the transfer mechanism  20  in X direction (S 5 )  
     [0054] The processed wafer, which was transferred and to which predetermined processes, e.g. deposition and etching, were carried out in the processing device  12 A, has been transferred to the first buffer supporting table  36 A in the load-lock chamber  10 A to stand by. At this time, if the gate valve  34 A is open, the pressure-regulated load-lock chamber  10 A is communicated with the common transfer chamber  8 . Then, first, the lower-stage empty transfer arm  72  is driven to pick up and hold the processed wafer W, which stands by on the first buffer supporting table  36 A, by the fork  72 A (S 6 ). Thus, since the first buffer supporting table  36 A is emptied, the upper-stage transfer arm  70  is driven to transfer the unprocessed wafer W, which is held by the fork  70 A, to the first buffer supporting table  36 A (S 7 ).  
     [0055] Thus, when the unprocessed wafer is replaced with the processed wafer, the transfer mechanism  20  simultaneously hold the unprocessed and processed wafers. However, since the unprocessed wafer is held by the upper-stage transfer arm  70  and the processed wafer is held by the lower-stage transfer arm  72  as described above, the processed wafer is positioned below the unprocessed wafer. Therefore, even if an undesired film produced during deposition is peeled off from the processed wafer or shavings produced during etching are peeled off to drop particles, it is possible to prevent the particles from adhering to the unprocessed wafer.  
     [0056] After the unprocessed wafer is thus held by the lower-stage transfer arm  72 , the transfer mechanism  20  is moved in X direction to a predetermined cassette vessel, e.g.  18 C (S 8 ). Then, the processed wafer W held by the lower-stage transfer arm  72  is transferred to a predetermined position in the cassette vessel  18 A (S 9 ). Furthermore, before this, the gate valve  34 A is closed in the load-lock chamber  10 A, and the unprocessed wafer on the first buffer supporting table  36 A is transferred to the supporting table  14 A in the processing device  12 A by means of the separate transfer mechanism  40 A. Then, a predetermined processing is carried out therein.  
     [0057] Since the upper-stage transfer arm  70  is thus always used when the unprocessed wafer W is transferred from the orienter  32  to the load-lock chamber  10 A or  10 B of one processing device  12 A or  12 B, the unprocessed wafer is always positioned above the processed wafer even if the processed wafer crosses the unprocessed wafer at vertical positions when the unprocessed wafer is replaced with the processed wafer. Therefore, it is possible to prevent particles from adhering to the unprocessed wafer.  
     [0058] Since the upper-stage transfer arm  70  is always used when the positioned wafer is transferred from the orienter  32 , the teaching operation with a high transfer precision is carried out with respect to only the upper-stage transfer arm  70  and is not required to be carried out with respect to the lower-stage transfer arm  72 , so that the teaching operation can be rapidly and simply carried out.  
     [0059] Since the two transfer arms  70  and  72  are arranged in the upper and lower two stages so as to overlap in vertical directions, the plane size thereof can be greatly decreased unlike conventional systems wherein two transfer arms are arranged on the same horizontal plane. In fact, in conventional systems, the width H1 of the common transfer chamber  8  in FIG. 1 must be about 100 cm in the case of a wafer having a size of 300 mm. However, in the processing system according to the present invention, the width H1 is only about 40 to 50 cm, so that the width H1 can be greatly decreased.  
     [0060] In this preferred embodiment, as shown by S 1  in FIG. 5, the lower-stage transfer arm  72  is used when the unprocessed wafer in the cassette vessel is picked up. However, when the orienter  32  is empty, any one of the transfer arms in the upper and lower stages may be used.  
     [0061] While the processing devices  12 A and  12 B having both of the load-lock chambers  10 A and  10 B has been described as an example since the vacuum processing has been carried out therein, it is not always required to provide the load-lock chambers in accordance with the form of a processing, e.g., in the case of a processing device for carrying out oxidation and diffusion at ordinary pressure.  
     [0062] While the processing system wherein the load-lock chambers  10 A and  10 B are connected to the elongated box-shaped common transfer chamber  8  via the processing devices  12 A and  12 B and wherein the transfer mechanism  20  is slidably provided in the common transfer  8 , has been described as an example, the present invention should not be limited thereto. For example, as shown in FIG. 6, the present invention can be applied to a so-called cluster tool type processing system wherein the same transfer mechanism  20  (without no slide in X directions) as that shown in FIG. 1 is provided at the center in a polygonal, e.g., hexagonal, common transfer chamber  8 , and, e.g. four processing devices  12 A through  12 D and two cassette chambers  16 A and  16 B are provided around the transfer mechanism  20 .  
     [0063] In this case, an orienter  32  comprising a reference table  52  and an optical sensor  64  is provided in a part of the hexagonal common transfer chamber  8 . In the same manner as that described above, the upper-stage transfer arm  70  of the transfer mechanism  20  is used when the semiconductor wafer W positioned by the orienter  32  is transferred to the respective processing devices  12 A through  12 D. Also in this case, the same advantageous effects as those described above can be obtained.  
     [0064] Thus, the present invention can be applied to all of processing systems including the orienter  32 . Therefore, of course, the present invention can be applied to a so-called cluster tool type processing system wherein a plurality of processing devices and an orienter are connected to the respective sides of a polygonal, e.g. rectangular or hexagonal, common transfer chamber, or a processing device wherein an orienter is included in the above described common transfer chamber.  
     [0065] While the semiconductor wafer W has been described as an example of a processing object, the present invention should not be limited thereto, but the present invention maybe applied to glass substrates and LCD substrates.  
     [0066] As described above, according to the present invention, since the transfer arms of the transfer mechanism are provided in upper and lower two stages, the transfer mechanism itself can be miniaturized to greatly decrease the space occupied by the whole system. In addition, since the lower-stage transfer arm is used when the processed object is held to be transferred, it is possible to prevent particles from adhering to the unprocessed object even if the unprocessed object is simultaneously held by, e.g. the upper-stage transfer arm.  
     [0067] In addition, the teaching operation can be rapidly and simply carried out since the positional precision is low when the teaching operation may be carried out with respect to the lower-stage transfer arm if the position adjustment is accurately carried out when the teaching operation is carried out with respect to the upper-stage transfer arm.