Abstract:
A multi-chamber system of an etching facility for manufacturing semiconductor devices occupies a minimum amount of floor space in a clean room by installing a plurality of processing chambers in multi-layers and in parallel along a transfer path situated between the processing chambers. The multi-layers number  2  to  5 , and the transfer path can be rectangular in shape and need only be slightly wider than the diameter of a wafer. The total width of the multi-chamber system is the sum of the width of one processing chamber plus the width of the transfer path.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. non-provisional application Ser. No. 11/167,175, filed Jun. 28, 2005, which is a continuation of U.S. non-provisional patent application Ser. No. 10/298,605, filed Nov. 19, 2002, and now U.S. Pat. No. 6,930,050, which is a divisional of U.S. non-provisional patent application Ser. No. 09/237,229, filed Jan. 26, 1999, and now U.S. Pat. No. 6,503,365. A claim of priority is also made to Korean patent application no. 1998-14228, filed Apr. 21, 1998. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a multi-chamber system of an etching facility for manufacturing semiconductor devices, and more particularly, to a multi-chamber system of an etching facility for manufacturing semiconductor devices which minimizes the space occupied by the facility by aligning a plurality of processing chambers with a transfer path in the center. 
         [0004]    2. Description of the Related Art 
         [0005]    The manufacturing of semiconductor devices involves many processes, including photolithography, etching, and thin film formation, which are repeatedly carried out during the manufacturing process. Generally, the etching process is carried out in a “focus-type” multi-chamber system which is capable of processing various process steps for wafers at the same time. 
         [0006]    In particular, the multi-chamber system for a dry-etching process using plasma is operated with a plurality of processing chambers in which a high-vacuum state environment for the generation of plasma is formed. The system includes an inner transfer device for transporting wafers from a central chamber under a low vacuum state to the plurality of high vacuum processing chambers. 
         [0007]      FIG. 1  illustrates a conventional focus-type multi-chamber system for a dry-etching process using plasma, which is constructed in such a manner that a hexagonal pillar-shaped central chamber  16  is located in its center; four processing chambers  15  are connected to four sides of the central chamber  16 , and between the central chamber  16  and each of the processing chambers  15 , there is formed a gate (not shown) for allowing the selective passage of wafers. An inner transfer device  14  inside the central chamber  16  is able to selectively load and unload the wafers into each processing chamber  15  through the gate. Note that the central chamber  16  can be formed as a square, pentagon, hexagon shape, etc., and  FIG. 1  shows the normal hexagonal shape of the central chamber  16 . Further, there is provided a vacuum pressure generator (not shown) in each of the processing chambers  15  and the central chamber  16 . 
         [0008]    Therefore, the inner transfer device  14  transports wafers to the processing chamber  15  under the vacuum pressure environment. In addition to the central chamber  16 , a load lock chamber  13 , serving as a stand-by area for the wafers under a low vacuum state, is located between the central chamber  16  and the wafers which are under atmospheric pressure in cassettes  11 . 
         [0009]    The load lock chamber  13  comprises an input load lock chamber for stacking wafers before processing, and an output load lock chamber for stacking wafers after processing. 
         [0010]    In addition to the two load lock chambers  13 , there is connected a cassette stage  12  having the cassettes  11  mounted thereon for easy transportation of wafers under atmospheric pressure. 
         [0011]    Therefore, in the conventional multi-chamber system, if the cassette  11  is mounted on the cassette stage  12 , an operator or the automatic transfer mechanism, etc., inside the load lock chamber  13  transfers the cassette  11  having wafers thereon to the load lock chamber  13 , and then, the load lock chamber  13  is sealed and placed under a low vacuum state. When the load lock chamber  13  reaches a certain level of vacuum, the gate of the load lock chamber  13  is opened, an inner transfer device  14  inside the central chamber  16  mounts wafers individually or in groups on a transfer arm (not shown) under a low vacuum state, and transfers them to a specific processing chamber  15  by rotating horizontally a certain angle, and proceeding toward the specific processing chamber  15 . 
         [0012]    In addition, after wafers are transported into the processing chamber  15 , the gate of the processing chamber  15  is shut, and a specific corresponding process is carried out. The processed wafers are removed from the processing chamber by the inner transfer device  14  of the central chamber  16 , and stacked on the cassette  11  inside the load lock chamber  13 . 
         [0013]    Here, while a specific process is carried out inside a specific processing chamber  15 , the inner transfer device  14  is capable of continuously loading and unloading wafers to another processing chamber  15 . Therefore, a plurality of wafers can be processed inside a plurality of processing chambers  15  at the same time. 
         [0014]    However, the conventional multi-chamber system, which is constructed as described above, i.e., the hexagonal pillar shaped central chamber  16 , four processing chambers  15  and two load lock chambers  13  surrounding the central chamber  16 , occupies a space of width “W” inside the fabrication line layout, requiring a large vacuum facility to maintain the central chamber  16  in a vacuum state and increasing the expenses for the facilities and their installation. 
         [0015]    In addition, the space taken up by the central chamber increases with the number of processing chambers. For instance, six processing chambers and two load lock chambers require an octagonal pillar shaped central chamber which takes up more space than the hexagonal pillar-shaped central chamber shown in  FIG. 1 . 
         [0016]    Therefore, if the number of processing chambers is increased, a different multi-chamber system is necessary, occupying additional cleanroom space and requiring additional expense. Various process gases and vacuum-related apparatus connected to the processing chamber or the load lock chamber must also be installed in duplicate. 
         [0017]    An attempt to increase the number of processing chambers of the focus-type multi-chamber system, as shown in  FIG. 2 , comprises two central chambers  16 , each connected to three processing chambers  15 . The two central chambers  16  are connected to each other by a connection load lock chamber  17  between them. Two of the conventional focus-type multi-chamber systems  10  are thereby connected. 
         [0018]    However, the installation of the six processing chambers  15  and one connection load lock chamber  17  as shown in  FIG. 2  costs more than the installation of an additional focus-type multi-chamber system  10  as shown in  FIG. 1 , and the seven-chamber set-up still occupies a lot of space in the cleanroom, and requires duplicate installation of various processing gases and vacuum-related apparatus. 
         [0019]    Furthermore, as shown in  FIG. 3 , the conventional focus-type multi-chamber system  10  is normally installed inside the cleanroom along with other facilities  20 , with the cassette stages on the other facilities all being disposed to one side. Therefore, it is necessary for an operator or an automatic cassette car to transport cassettes between facilities. 
         [0020]    In addition to the disadvantages of the focus-type multi-chamber system, the inner transfer device moves wafers under a vacuum state, and therefore, the wafers cannot be attached by vacuum-absorption, and are simply gravity-supported by the transfer arm. The wafers must therefore be moved at a low speed so as not to be displaced from the transfer arm, which results in a very slow wafer transfer operation. 
       SUMMARY OF THE INVENTION 
       [0021]    The present invention is directed to a multi-chamber system of an etching facility for manufacturing semiconductor devices for greatly reducing the space and the width occupied by the facilities by aligning a plurality of processing chambers in multi-layers and in parallel, which substantially overcomes one or more of the problems due to the limitations and the disadvantages of the related art. 
         [0022]    To achieve these and other advantages and in accordance with the purpose of the present invention, the multi-chamber system for manufacturing semiconductor devices comprises: a cassette stage for mounting a cassette having wafers stacked thereon; a transfer path adjacent to the cassette stage and having a width slightly larger than the diameter of the wafers, preferably with a rectangular-shape, for providing a space for the transportation of wafers; a plurality of processing chambers aligned with the transfer path; and a transfer mechanism installed in the transfer path for loading and unloading the wafers stacked on the cassette stage to the plurality of processing chambers. 
         [0023]    In addition, the processing chambers are disposed in multiple layers, and a load lock chamber may be connected to one side of the processing chamber to serve as a stand-by area for the wafers. 
         [0024]    The load lock chamber may comprise: a transfer arm for receiving the wafers from the transfer mechanism and transferring the wafers to the processing chamber; an inner transfer device for moving the transfer arm; and gates formed on the side of the transfer path and the side of the processing chamber, respectively, the gates being selectively opened and closed to allow passage of the wafers. 
         [0025]    Preferably, the transfer mechanism comprises: a transfer arm for selectively holding the wafers; a transfer robot for loading and unloading the wafers into the processing chamber by moving the transfer arm; a horizontal driving part for moving the transfer robot horizontally; and a controller for controlling the transfer robot and the horizontal driving part by applying control signals thereto. 
         [0026]    The transfer mechanism may further comprise a vertical driving part for moving the transfer robot vertically on receipt of a control signal from the controller. In addition, a vacuum line is preferably installed on the transfer arm so as to vacuum-absorb wafers. 
         [0027]    In addition, the transfer path may be extended and a plurality of transfer mechanisms installed such that wafers can be transferred from one transfer mechanism to another. 
         [0028]    Prior to processing, the wafers are stacked on a cassette mounted on a first cassette stage. The wafers are then transferred to the processing chambers; and the processed wafers are transferred to a second cassette stage which is located such that the wafers are easily transferred to a subsequent process. 
         [0029]    In another aspect of the present invention, a multi-chamber system for manufacturing semiconductor devices comprises: a cassette stage for mounting a cassette having wafers stacked thereon; a rectangular-shaped transfer path adjacent to the cassette stage for providing space for transportation of wafers; a plurality of processing chambers aligned in multi-layers parallel to and beside the transfer path; and a transfer mechanism capable of vertical/horizontal reciprocal movement installed in the transfer path for loading and unloading the wafers stacked on the cassette stage to the plurality of processing chambers. 
         [0030]    The transfer mechanism comprises: a transfer arm having a vacuum line installed thereto so as to selectively vacuum-absorb wafers; a transfer robot for loading and unloading the wafers into the processing chamber by moving the transfer arm; a vertical driving part for moving the transfer robot vertically; a horizontal driving part for moving the transfer robot horizontally; and a controller for controlling the transfer robot, the vertical driving part, and the horizontal driving part by applying control signals thereto. 
         [0031]    In another aspect of the present invention, a multi-chamber system for manufacturing semiconductor devices comprises: a first cassette stage for mounting a cassette having unprocessed wafers stacked thereon; a transfer path with a rectangular shape adjacent to the cassette stage for providing space for the transportation of wafers; a plurality of processing chambers arranged in multi-layers and aligned in parallel beside the transfer path; a transfer mechanism capable of vertical/horizontal reciprocal movement installed in the transfer path for loading and unloading the wafers stacked on the first cassette stage to the plurality of the processing chambers; and a second cassette stage placed opposite to the first cassette stage and mounting a cassette having processed wafers stacked thereon. 
         [0032]    The transfer mechanism comprises: a transfer arm having a vacuum line for selectively vacuum-absorbing wafers; a transfer robot for loading and unloading wafers to the processing chamber by moving the transfer arm; a vertical driving part for vertically moving the transfer robot; a horizontal driving part for horizontally moving the transfer robot; and a controller for controlling the transfer robot, the vertical driving part, and the horizontal driving part by applying control signals thereto. 
         [0033]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification illustrate embodiments of the invention, wherein like reference numerals refer to like elements throughout, in which: 
           [0035]      FIG. 1  is a plan view of a conventional multi-chamber system of an etching facility for manufacturing semiconductor devices; 
           [0036]      FIG. 2  is a plan view of two of the multi-chamber systems of  FIG. 1  connected to each other; 
           [0037]      FIG. 3  is a plan view of two of the multi-chamber systems of  FIG. 1  installed inside a semiconductor device fabrication line; 
           [0038]      FIG. 4  is a plan view of a multi-chamber system of an etching facility for manufacturing semiconductor devices according to one embodiment of the present invention; 
           [0039]      FIG. 5  is a perspective view of the multi-chamber system of  FIG. 4 ; 
           [0040]      FIG. 6  is a side view schematically showing the transportation state of the wafers of in the multi-chamber system of  FIG. 5 ; 
           [0041]      FIG. 7  is a plan view showing a multi-chamber system of an etching facility for manufacturing semiconductor devices according to a second embodiment of the present invention; 
           [0042]      FIG. 8  is a plan view of the multi-chamber system of  FIG. 7  installed inside a semiconductor device fabrication line; 
           [0043]      FIG. 9  is a plan view of an extended version of the embodiment of the present invention shown in  FIG. 7 ; and 
           [0044]      FIG. 10  is a plan view of a third embodiment of the multi-chamber system of an etching facility for manufacturing semiconductor devices of the present invention installed inside a semiconductor device fabrication line. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0045]    Reference will now be made in detail to preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
         [0046]      FIG. 4  is a plan view showing a multi-chamber system of an etching facility for manufacturing semiconductor devices according to one preferred embodiment of the present invention. Referring to  FIG. 4 , the multi-chamber system is constructed in such a manner that a cassette  41  having wafers stacked thereon is mounted on a cassette stage  42 , and eight processing chambers  45  for carrying out processes are displaced in parallel with multi-layers on both sides of a transfer path  100 , four of which are shown in the plan view of  FIG. 4 . The transfer path  100  has a shape having a narrow width, preferably a rectangular shape, and a transfer mechanism  52  is provided in the transfer path  100  in order to load and unload the wafers stacked on the cassette stage  42  into each of the eight processing chambers  45 . 
         [0047]    The cassette stage  42  includes a cassette elevator for moving the cassette up and down and can be moved horizontally so as to switch the locations of cassettes. 
         [0048]    The processing chambers  45  can be aligned in a single layer, but considering the efficiency of the space, a two-layer arrangement may be used as shown in  FIG. 5 , each layer having four processing chambers  45  aligned in parallel. With this arrangement, each layer comprises four processing chambers  45 , two load lock chambers  43  which are the same size as those in the conventional multi-chamber system  10  of  FIG. 1 , and one transfer path  100 . Therefore, the facility width “W” of the multi-chamber system  40  of the present invention is the sum of the widths of those of the two processing chambers  45  and the one transfer path  100 . This width “W” is minimized, because the width of the hexagonal pillar-shaped central chamber in the conventional system is replaced by that of the transfer path  100  in the multi-chamber system, and the transfer path  100  is only a little wider than the diameter of one wafer. 
         [0049]    In addition, the depth of the multi-chamber system is minimized, because the depth of the hexagonal pillar-shaped central chamber, each side of which is slightly larger than the diameter of a wafer, is replaced by that of the load lock chamber  43 . The shape of the load lock chamber  43  can be optimized as a regular rectangular pillar shape so as to be only slightly deeper than the diameter of one wafer, thereby decreasing the width and depth of the whole facility. 
         [0050]    Therefore, the area occupied by a single-layer structure (not shown) of the multi-chamber system according to the present invention is less than the area occupied by the conventional system; and the multi-layer structure as shown in  FIGS. 4 and 5  is even more compact. Furthermore, the multi-layer structure preferably has 2 to 5 layers. 
         [0051]    In addition, the space occupied by the load lock chamber  43  can be minimized, and the volume of the vacuum facility or supplementary apparatus can be reduced, thereby minimizing expenses for the facility and its installation. 
         [0052]    In addition, as described below, the transfer mechanism  52  allows wafers to be moved quickly by holding them using vacuum pressure so that it is not necessary to install a supplementary vacuum pressure generator. 
         [0053]    A vacuum is not formed in the transfer path  100 , unlike the case of the conventional central chamber, thereby allowing use of the multi-layer structure for the processing chambers. Since a vacuum is not formed in the transfer path  100 , the wafers may be vacuum absorbed to the transfer arm thus providing faster wafer transfers, in contrast to the conventional case, wherein the wafers inside the central chamber were merely gravity-supported by the transfer arm, and the wafers had to be moved slowly so as not to fall off the transfer arm. 
         [0054]    For those processing chambers requiring a relatively low vacuum state, such as a base oven process, an ashing process, a pre/post etching process, etc., a gate (not shown) is formed toward the transfer path  100  and is selectively opened and closed so as to allow for the passage of wafers. 
         [0055]    A vacuum pressure generator  45 ′ is installed inside the processing chamber  45  in order to form a vacuum pressure therein, with the processing chamber  45  carrying out the dry-etching process requiring a high-vacuum to form a plasma. 
         [0056]    Therefore, in order to minimize the time or the energy waste necessary to form a high-vacuum state in the processing chamber after being directly exposed to the atmospheric pressure environment, a load lock chamber  43  having a low-vacuum state is connected to one side of the processing chamber  45  and serves as a stand-by region for wafers, and a gate  46 ,  49  is formed on one side of the load lock chamber  43  facing the transfer path  100 . 
         [0057]    Each load lock chamber  43  comprises: a transfer arm  54  ( FIG. 6 ) for receiving wafers from the transfer mechanism  52  and transferring them to the processing chamber; an inner transfer device  44  for moving the transfer arm  54 ; a gate  46 ,  49  formed on one side of the transfer path  100  which is selectively opened and closed to allow the passage of wafers; and another gate  47 ,  48 ,  50 ,  51  provided on one side of the processing chamber  45  that is selectively opened and closed to allow the passage of wafers between the processing chamber  45  and the load lock chamber  43 . 
         [0058]    Here, the transfer arm  54  of the load lock chamber  43 , and the inner transfer device  44  inside the chamber can be provided in each of the two load lock chambers  43  so as to individually transfer two wafers into the two processing chambers  45  simultaneously. 
         [0059]    A vacuum pressure generator  43 ′ may be provided in the load lock chamber  43  so as to form a low-vacuum therein in order to prevent an abrupt vacuum pressure differential inside the processing chamber  45  when the wafers are transferred through the gate  47 , 48 ,  50 ,  51  between the high vacuum processing chamber  45  and the load lock chamber  43 . Such a vacuum pressure generator  43 ′ using a vacuum pump is well-known to those skilled in the art. 
         [0060]    In addition, as shown in  FIG. 4  and  FIG. 5 , two processing chambers  45  are placed on both sides, i.e., before and after the load lock chamber  43 , respectively, so as to have one load lock chamber  43  in common. In other embodiments, three or more processing chambers  45  may be oriented so as to share one common load lock chamber. 
         [0061]    Since the processing chambers  45  are connected to one another through the gates, wafers passing through one specific process are directly moved to another processing chamber, thereby allowing the transfer of wafers between processing chambers. 
         [0062]    As shown in  FIGS. 5 and 6 , the transfer mechanism  52  of the present invention installed on the transfer path  100  comprises: a transfer arm  53  for selectively holding the wafers; a transfer robot  52   a  for loading and unloading wafers to the processing chamber by moving the transfer arm  53 ; a horizontal driving part  52   b  for horizontally moving the transfer robot; a vertical driving part  52   c  for moving the transfer robot up and down; and a controller  52   d  for applying a control signal to the transfer robot  52   a , the horizontal driving part  52   b , and the vertical driving part  52   c . The transfer arm  53  further includes a vacuum line  52   e  in order to selectively vacuum-absorb wafers  1  placed thereon. The horizontal and vertical movement is indicated by the arrows in  FIGS. 5 and 6 . 
         [0063]    The transfer arm  53 , as shown in  FIG. 5 , can be constructed such that one wafer is transferred at a time, but can also be constructed as a 4-arm system, wherein four arms are connectably provided in two layers so as to individually transport four wafers at the same time to the load lock chambers. Such a 4-arm system for transferring four wafers individually at a time, or 2-arm system, 3-arm system, etc., which are employed so as to move 2 or 3 wafers at a time, are well-known to those skilled in the art. 
         [0064]    Also well-known to those skilled in the art are: the horizontal driving part  52   b , which horizontally moves along a rail or guide rod by using a motor or an air cylinder as a driving source, the vertical driving part  52   c , which moves up and down along a rail or guide rod; the transfer arm  53  and the transfer robot  52   a . Various modifications or alterations of these mechanisms are contemplated within the scope of the present invention. 
         [0065]    The multi-chamber system for manufacturing semiconductor devices as shown in  FIG. 6  is constructed in such a manner that a cassette  41  having a plurality of wafers  1  stacked therein is mounted on the cassette stage  42 , and the horizontal driving part  52   b  and the vertical driving part  52   c  of the transfer mechanism  52  are driven on receipt of the control signal from a controller  52   d  so as to control the movement of the transfer robot  52   a  toward the wafers  1  inside the cassette  41 . 
         [0066]    In operation, the transfer mechanism  52  accesses the wafer  1 , the transfer robot  52   a  receives the control signal from the controller  52   d , and then makes the transfer arm  53  contact the wafers  1 . The transfer arm  53  having the vacuum line  52   e  vacuum-absorbs the wafers  1  to one side of the transfer arm  53 . 
         [0067]    When the wafer  1  fixed on the transfer arm  53  is to be moved to a specific processing chamber  45  disposed in the first chamber layer, the wafer  1  is first moved to the load lock chamber  43  connected to the specific chamber  45  in the first chamber layer by the horizontal driving part  52   b  under control from the controller  52   d.    
         [0068]    At this time, the gate  46  of the load lock chamber  43  facing the transfer path  100  is opened, and the transfer arm  53  of the transfer mechanism  52  is inserted. Then the vacuum pressure of the vacuum line  52   e  is shut off, and the wafer  1  is mounted on the transfer arm  54  inside the load lock chamber  43 . 
         [0069]    The transfer arm  53  of the transfer mechanism  52  exits the load lock chamber  43 , and the gate  46  is then closed. Then, the vacuum pressure generator  43 ′ of the load lock chamber  43  is operated so as to place the inside of the load lock chamber  43  into a low vacuum state. 
         [0070]    After the load lock chamber  43  reaches a certain low vacuum level, the gate (e.g., gate  47 ) of the load lock chamber  43  facing the processing chamber  45  is opened, and the inner transfer device  44  of the load lock chamber  43  transfers the wafers mounted on the transfer arm  54  into the processing chamber  45 . 
         [0071]    While vacuum absorption of the wafer at this stage is difficult because of the low vacuum pressure state in the load lock chamber  43 , the small space within the load lock chamber  43  is not as wide as in the conventional one, so that it takes just a short time for the transfer arm  54  to mount the wafers in the processing chamber  45 , even at the low speed. 
         [0072]    Then the transfer arm  54  exits the processing chamber  45 , the gate  47  is closed, and the vacuum pressure generator  45 ′ in the processing chamber  45  is operated, thereby forming a high vacuum inside the processing chamber  45 , after which the etching process is carried out. 
         [0073]    Meanwhile, if the wafers  1  are to be moved to a specific processing chamber  45  on the second chamber layer, the controller  52   d  controls both the horizontal driving part  52   b  and the vertical driving part  52   c  so as to transfer the wafers  1  to the load lock chamber  43  connected to the specific processing chamber  45  on the second chamber layer. 
         [0074]    The wafers  1  are moved up while vacuum absorbed by the transfer arm  53  of the transfer robot  52   a , and are inserted into the load lock chamber  43 . The subsequent steps are the same as described above for a processing chamber on the first layer. 
         [0075]    When the wafers have been transferred and loaded into a plurality of processing chambers  45 , corresponding processes are carried out in the respective processing chambers, and the wafers are unloaded in order of process completion. Then, the wafers are transferred to the cassette stage  42  or transferred to a specific processing chamber on a specific layer upon receipt of a control signal from the controller  52   d.    
         [0076]    When a 4-arm system is installed on the transfer mechanism  52 , the transfer mechanism  52  picks up four wafers from the cassette and places two wafers into each of two load lock chambers  43  connected to specific processing chambers. When the inner transfer device  44  and the transfer arm  54  are constructed with a 2-arm system, two wafers are picked up and transferred, one each into two processing chambers. After processing, two or one wafer is transferred from the processing chamber to the transfer mechanism  52  so as to carry out a post-process step. 
         [0077]    In another aspect of the present invention as shown in  FIG. 7 , a multi-chamber system of an etching facility for manufacturing semiconductor devices comprises: a first cassette stage  60  for mounting a cassette containing unprocessed wafers; a second cassette stage  70  for mounting a cassette containing processed wafers; a plurality of processing chambers  45  aligned on both sides of a rectangular-shaped transfer path  100 , the processing chambers being arranged in parallel in a multi-layered path for wafers, and for carrying out processing of wafers; and a transfer mechanism  52  installed in the path allowing for vertical/horizontal reciprocal movement, and including a transfer robot for transferring wafers mounted on the first cassette stage  60  to the plurality of processing chambers  45 , and for transferring wafers into the second cassette stage  70  after processing. 
         [0078]    This embodiment is constructed such that the wafers passing through all of the processing detailed above in the description of the first embodiment are stacked on the second cassette stage  70 , and such that the multi-chamber system is easily connected to other processing facilities  20  as shown in  FIG. 8 . 
         [0079]    Referring to  FIG. 8 , wafers are supplied into the multi-chamber system through the first cassette stage  60  installed in the front of the facility, and pass through a plurality of processes in the plurality of processing chambers  45 , and are stacked on the second cassette stage  70  on the back side of the facility. Then, wafers are moved to another facility  20  by an automatic transfer part of the other facility  20 , pass through processing therein, are transferred into the side of a second facility  20 ′, pass through that facility  20 ′, and are stacked on the cassette stage of the second facility  20 ′ on the right side of the multi-chamber system. 
         [0080]    Therefore, unlike the conventional case, wherein all cassette stages are provided on the front sides of the facility, therefore requiring a supplementary cassette transfer car in order to transport the cassette between facilities, the necessity for a supplementary cassette transfer means for transporting cassettes between facilities is reduced according to the present invention. 
         [0081]    In addition, as shown in  FIG. 9 , the number of processing chambers  45  can be increased, and the transfer path  100  extended, so that more processing chambers  45  and load lock chambers  43  are aligned on both sides of the transfer path  100 . 
         [0082]    When the length of the transfer path  100  is extended, a first transfer mechanism  62  and a second transfer mechanism  72  can be installed, wherein the transfer from one to the other is possible. 
         [0083]    Therefore, unlike the conventional multi-chamber system, the number of processing chambers can be increased without changing the width of the facility. However, there are limitations in the length of the facility and the facility control, etc. 
         [0084]    According to a third embodiment of the present invention, as shown in  FIG. 10 , a multi-chamber system of an etching facility for manufacturing semiconductor devices comprises: a cassette stage  42  for mounting a cassette having wafers stacked thereon; a plurality of processing chambers  45  aligned along one side of a transfer path  100 , the processing chambers being arranged in multi-layers for carrying out wafer processing; and a transfer mechanism  52  provided in the transfer path  100  for loading and unloading wafers into the plurality of processing chambers using vertical and horizontal movement. The processing chambers  45  and the load lock chambers  43 , which are stand-by areas for wafers, are aligned on only one side of the transfer path  100 . 
         [0085]    As above, each load lock chamber  43  comprises: a transfer arm for transferring wafers from the transfer mechanism  52  to the processing chamber; an inner transfer device for transferring the transfer arm; a gate confronting the transfer path and another gate confronting the processing chamber, which are selectively opened and closed to allow passage of the wafers. 
         [0086]    The transfer mechanism  52  of the third embodiment of the present invention, unlike the first and the second embodiments of the present invention, loads the wafers on the first cassette stage  60  in only one direction after horizontally-rotating 90 degrees while vacuum-absorbing the wafers, because the processing chambers  45  and the load lock chambers  43  are aligned along only one side. 
         [0087]    The transfer mechanism  52  transports unprocessed wafers stacked on the cassette mounted on the first cassette stage  60  to the processing chamber  45 , and after processing, transports the wafers from the processing chamber to the second cassette stage  70 , which is located for easy transfer to subsequent processes. 
         [0088]    That is, as shown in  FIG. 10 , the second cassette stage  70  is displaced on the opposite side of the transfer path from the processing chambers  45  and the load lock chambers  43 , so that the wafers after one process are easily transported to subsequent processes. 
         [0089]    Therefore, according to the third embodiment of the present invention, the efficiency of space usage is increased by applying the multi-chamber system of the present invention to the rest of the space in the cleanroom after installing various facilities with various shapes and volumes. 
         [0090]    Accordingly, in the multi-chamber system of an etching facility for manufacturing semiconductor devices, a plurality of processing chambers are aligned in parallel and with multi-layers, thereby greatly reducing the space, width and volume of the facility. Further, the expenses for the facilities and installation can be minimized by reducing the space requiring a vacuum state, and the connection with other processing facilities is easy, such that the efficiency of space usage is improved thereby increasing the transportation speed of wafers. 
         [0091]    In the accompanying drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims. 
         [0092]    It will be apparent to those skilled in the art that various modifications and variations of the present invention can be made without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.