Abstract:
A method for transporting a substrate between a carrier, which holds the substrate, and a semiconductor manufacturing unit, which receives the substrate. The method includes steps of applying the carrier, which holds the substrate, to a chamber, which houses the semiconductor manufacturing unit, in which chamber the environment of the semiconductor manufacturing unit is controlled, rotatably removing, by an opener, a door of the carrier and a door of the chamber, as a unit, from the carrier and the chamber, and transferring the substrate from the carrier and to the carrier, when the door of the carrier and the door of the chamber have been rotatably removed as a unit by the opener in the removing step. Also disclosed are semiconductor manufacturing apparatus utilizing such a method.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method for automatically transporting tabular substrates such as photomasks and reticles (hereinafter, generally referred to as reticles), or wafers and glass plates (hereinafter, generally referred to as wafers), and for transporting cassettes and carriers receiving the same. The present invention also relates to semiconductor manufacturing apparatuses using the method for processes such as exposure, rinsing, and inspection. 
     2. Description of the Related Art 
     Hitherto, reticle transporting devices and wafer transporting devices have been provided in semiconductor manufacturing apparatuses used in manufacturing processes of semiconductors, and in particular, in the semiconductor exposure apparatuses used in an exposure process. The transporting devices have been used in view of transporting efficiency and dust-proofing in order to improve the throughput and output rate. 
     The reticles used in the exposure process are typically transported in carriers, which receive the reticles one by one or in units of a plurality of reticles, from a reticle storage to each exposure apparatus, either manually or by an automatic transporting apparatus such as an AGV (automated guided vehicle) and OHT (over-head transfer) device, and are stored in storage shelves (hereinafter referred to as a library) provided in the exposure apparatus or in the vicinity thereof. The reticles thus stored are required to be delivered to an exposure stage in the exposure apparatus at a very high speed and with high accuracy. Particularly, due to the trend of limited productions of a wide range of products, the quantity of reticles to be stored in the library has recently increased according to the increasing varieties of devices to be manufactured. 
     Semiconductors are generally manufactured in clean rooms with a very high level of cleanliness class (low class number). In a process in which dust particles are strictly controlled, such as an exposure process, an exposure apparatus is installed in a clean chamber provided in a clean room, the clean chamber being maintained at a cleanliness of class  1  of particle sizes ranging from 0.1 μm to 0.2 μm. 
     Recently, a mini-environment philosophy known as an SMIF (Standardized Mechanical Interface) has been proposed which is disclosed, for example, in U.S. Pat. No. 4,532,970. This philosophy has been proposed in view of the fact that the processing rooms need only be partially clean and because the operating costs of downflow clean rooms, in which entire rooms are cleaned, are high due to the fact that a higher level of dust particle control is required for next-generation gigabit devices and a higher production efficiency is required in view of a recent slowdown in the semiconductor industry. 
     FIGS. 11A to  11 D are side views of a known SMIF-type loading-port unit for reticles. An SMIF-type carrier unit  28 , receiving a plurality of reticles  1 , is set on a loading port  381 , as shown in FIG. 11A. A lock of a carrier door  282  is released by a lock releasing mechanism included in a loading-port door  383  (in FIG.  11 B). A reticle carrier library  283 , receiving the plurality of reticles  1 , is removed downwardly from a carrier  281 , while the carrier door  282  and the loading-port door  383  are supported as a unit (in FIG.  11 C). Thereafter, each of the reticles  1  is transferred by a transporting robot  42 , as shown in FIG.  11 D. 
     FIGS. 12A to  12 D are side views of an FOUP (Front-Opening Unified Pod) type loading-port unit, which is standardized according to the SEMI standard for handling 12-inch wafers (12 inches=300 mm). When an FOUP-type carrier unit  29  is set on a loading port unit  391 , as shown in FIG. 12A, the carrier unit  29  is positioned by kinematic coupling pins  392  and is applied to an outer wall of a chamber  6  by being pressed against the outer wall of the chamber  6  by an applying mechanism provided in the loading port unit  391 , as shown in FIG.  12 B. Then, the lock of a carrier door  292  is released by a lock releasing mechanism included in a chamber door  393 , and the carrier door  292  and the chamber door  393  are removed by an opener  394  from a carrier  291  and the chamber  6  at the front side of the carrier  291 , while the carrier door  292  and the chamber door  393  are held as a unit by a supporting mechanism included in the chamber door  393  (in FIG.  12 C). The carrier door  292  and the chamber door  393  are moved downwardly as a unit (in FIG.  12 D), thereby allowing transfer of the wafers  11  by a transporting robot  42 . 
     When a plurality of the loading port units is required, the SMIF-type loading port units must be disposed in a horizontal direction, because a large space in the vertical direction is occupied due to the configuration thereof, in which the reticle carrier library is removed downwardly and the reticles are transferred. That is, a disadvantage of the SMIF system is that the footprint of the units is increased. In the same way, when a plurality of units is required, the FOUP-type loading port units must be disposed in a horizontal direction, because a large space in the vertical direction is occupied due to the configuration thereof, in which the carrier doors are removed downwardly, thereby increasing the footprint of the units, which is a disadvantage of the FOUP system. 
     Another problem is that dust particles adhering to the substrates while they are transported between carriers and semiconductor manufacturing apparatuses are not considered in these known apparatuses. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a method for transporting substrates and a semiconductor manufacturing apparatus using the method, in which a plurality of loading ports are provided with a footprint thereof being minimized and, while being transported, the surfaces of substrates are kept clean by an air-blower mechanism, from the viewpoint of a mini-environment to be applied to semiconductor manufacturing facilities. 
     To these ends, in accordance with a first aspect of the present invention, a method for transporting a substrate between a carrier, which holds the substrate, and a semiconductor manufacturing unit, which receives the substrate, is provided, which comprises the steps of applying the carrier to a chamber, which houses the semiconductor manufacturing unit, in which chamber the environment of the semiconductor manufacturing unit is controlled, rotatably removing, by an opener, a door of the carrier and a door of the chamber, as a unit, from the carrier and the chamber, and transferring the substrate from the carrier and to the carrier when the door of the carrier and the door of the chamber have been rotatably removed as a unit by the opener. 
     The method for transporting a substrate may further comprise the step of releasing a lock of the door of the carrier by a lock releasing mechanism provided in the door of the chamber. 
     The method may still further comprise the step of supporting the door of the carrier and the door of the chamber as a unit by a supporting mechanism provided in the door of the chamber. 
     In the method for transporting a substrate, the door of the carrier and the door of the chamber may be horizontally removed as a unit from the carrier and the chamber by the opener, and then rotated around a rotation axis by the opener. 
     The rotation axis around which the door of the carrier and the door of the chamber rotate as a unit, while being removed, may be disposed on a plane extending from the interface between the chamber and the door thereof, which is sealed. 
     The door of the carrier and the door of the chamber may be rotated downwardly around the rotation axis as a unit by the opener. The opener may be provided on an inner wall of the chamber. 
     In the method, a plurality of the openers and a plurality of loading ports for receiving the carriers may be provided in the chamber. The loading ports may be provided overlapping each other in the vertical direction. 
     In the method, a library may be provided in the vicinity of the semiconductor manufacturing unit for storing a plurality of the substrates. 
     The carrier in the method may receive one of the substrates, and the substrate may be a reticle. 
     According to a second aspect of the present invention, a semiconductor manufacturing apparatus is provided, which comprises a semiconductor manufacturing unit housed in a chamber in which the environment of the semiconductor manufacturing unit is controlled, an applying mechanism for applying a carrier, which holds a substrate, to the chamber, an opener for rotatably removing a door of the carrier and a door of the chamber, as a unit, from the carrier and the chamber, and a transporting mechanism for transferring the substrate from the carrier and to the carrier when the door of the carrier and the door of the chamber have been rotatably removed as a unit, and for transporting the substrate between the carrier and the semiconductor manufacturing unit. 
     The door of the chamber may be provided with a lock releasing mechanism for releasing a lock of the door of the carrier. 
     The door of the chamber may be provided with a supporting mechanism for supporting the door of the carrier and the door of the chamber as a unit. 
     The door of the carrier and the door of the chamber may be horizontally removed as a unit from the carrier and the chamber by the opener, and then rotated around a rotation axis by the opener. 
     The rotation axis around which the door of the carrier and the door of the chamber rotate as a unit, while being removed, may be disposed on a plane extending from the interface between the chamber and the door thereof, which is sealed. 
     The door of the carrier and the door of the chamber may be rotated downwardly around the rotation axis as a unit by the opener. The opener may be provided on an inner wall of the chamber. 
     The semiconductor manufacturing apparatus may further comprise a plurality of the openers and a plurality of loading ports for receiving the carriers. 
     The loading ports may be provided overlapping each other in the vertical direction. 
     The semiconductor manufacturing apparatus may further comprise a library for storing a plurality of the substrates in the vicinity of the semiconductor manufacturing unit. 
     The carrier may receive one of the substrates, and in the semiconductor manufacturing apparatus, the substrate may be a reticle. 
     According to a third aspect of the present invention, a method for transporting a substrate between a carrier and a semiconductor manufacturing unit is provided, the method comprising the steps of applying the carrier, which holds the substrate, to a chamber in which the environment of the semiconductor manufacturing unit is controlled, removing a door of the carrier and a door of the chamber, as a unit, from the carrier and the chamber by an opener provided on a transporting robot for transporting the substrate, and transferring the substrate from the carrier and to the carrier by the transporting robot when the door of the carrier and the door of the chamber have been removed as a unit by the opener. 
     The method for transporting a substrate may further comprise the step of releasing a lock of the door of the carrier by a lock releasing mechanism provided on the door of the chamber. 
     The method may still further comprise the step of supporting the door of the carrier and the door of the chamber as a unit by a supporting mechanism provided on the door of the chamber. 
     In the method, a plurality of the openers and a plurality of loading ports for receiving the carriers may be provided in the chamber. The plurality of the loading ports may be provided overlapping each other in the vertical direction. The plurality of the openers may be disposed such that a distance therebetween is the same as a distance between each of the loading ports. 
     In the method, a library for storing a plurality of the substrates may be provided in the vicinity of the semiconductor manufacturing unit. 
     The carrier may receive one of the substrates, and in the method for transporting a substrate, the substrate may be a reticle. 
     According to a fourth aspect of the present invention, a semiconductor manufacturing apparatus comprises a semiconductor manufacturing unit provided in a chamber in which the environment of the semiconductor manufacturing unit is controlled, an applying mechanism for applying a carrier, which holds a substrate, to the chamber, an opener for removing a door of the carrier and a door of the chamber, as a unit, from the carrier and the chamber, and a transporting robot for transferring the substrate from the carrier and to the carrier when the door of the carrier and the door of the chamber have been removed as a unit by the opener. The opener is provided in the manufacturing apparatus on a side of the transporting robot. 
     In the semiconductor manufacturing apparatus, the door of the chamber may be provided with a lock releasing mechanism for releasing a lock of the door of the carrier. 
     The door of the chamber may be provided with a supporting mechanism for supporting the door of the carrier and the door of the chamber as a unit. 
     The semiconductor manufacturing apparatus may further comprise a plurality of loading ports for receiving the carriers, and a plurality of the openers. 
     The loading ports may be provided overlapping each other in the vertical direction. 
     The openers may be disposed such that a distance therebetween is the same as a distance between each of the loading ports. 
     The semiconductor manufacturing apparatus may further comprise a library for storing a plurality of the substrates in the vicinity of the semiconductor manufacturing unit. 
     The carrier may receive one of the substrates, and in the semiconductor manufacturing apparatus, the substrate may be a reticle. 
     According to a fifth aspect of the present invention, a method for transporting a substrate between a carrier and a semiconductor manufacturing unit is provided, the method comprising the steps of applying the carrier, which holds the substrate, to a chamber, which houses the semiconductor manufacturing unit, in which chamber the environment of the semiconductor manufacturing unit is controlled, removing a door of the carrier and a door of the chamber, as a unit, from the carrier and the chamber by an opener, transferring the substrate from the carrier and to the carrier by a transporting robot for transporting the substrate when the door of the carrier and the door of the chamber have been removed as a unit by the opener, and applying air to the substrate by an air-blower mechanism provided on the transporting robot when the transporting robot supports, at least when transporting, the substrate by a handling mechanism provided on the transporting robot. 
     The air applied by the air-blower mechanism may be temperature-controlled. 
     The transporting robot may include a cover for covering the substrate held by the handling mechanism of the transporting robot. 
     In the method, the air-blower mechanism may apply air to the substrate while the substrate is being transferred from the carrier. 
     The carrier may receive one of the substrates, and in the method for transporting a substrate, the substrate may be a reticle. 
     According to a sixth aspect of the present invention, a semiconductor manufacturing apparatus comprises a semiconductor manufacturing unit provided in a chamber in which the environment of the semiconductor manufacturing unit is controlled, an applying mechanism for applying a carrier, which holds a substrate, to the chamber, an opener for removing a door of the carrier and a door of the chamber as a unit from the carrier and the chamber, a transporting robot for transferring the substrate from the carrier and to the carrier when the door of the carrier and the door of the chamber have been removed as a unit by the opener, and an air-blower mechanism provided on the transporting robot, for applying air to the substrate when the transporting robot supports, at least when transporting, the substrate by a handling mechanism provided on the transporting robot. 
     The air applied by the air-blower mechanism may be temperature-controlled. 
     The transporting robot may include a cover for covering the substrate held by the handling mechanism. 
     The air-blower mechanism may apply air to the substrate while being transferred from the carrier. 
     The carrier may receive one of the substrates, and in the semiconductor manufacturing apparatus, the substrate may be a reticle. 
     Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     FIG.  1 A and FIG. 1B are side views showing an operation of a loading port unit according to a first embodiment of the present invention; 
     FIG.  2 A and FIG. 2B are top views showing the operation of the loading port unit according to the first embodiment of the invention; 
     FIG.  3 A and FIG. 3B are side views showing an operation of the loading port unit according to the first embodiment of the invention, further including a horizontal removing movement; 
     FIG. 4A, FIG. 4B, and FIG. 4C are top views showing the operation of the loading port unit according to the first embodiment of the invention, including the horizontal removing movement; 
     FIG. 5A, FIG. 5B, and FIG. 5C are side views showing an operation of the loading port unit according to a second embodiment of the present invention; 
     FIG. 6 is a side view of the loading port unit according to the second embodiment of the invention, in which two openers are provided such that a distance therebetween is the same as a distance between each loading port; 
     FIG.  7 A and FIG. 7B are side views showing an operation of the loading port unit according to the second embodiment of the invention, in which an FOUP system for wafers is applied; 
     FIG.  8 A and FIG. 8B are side views showing an operation of the loading port unit according to a third embodiment of the present invention; 
     FIG. 9 is a side view of the loading port unit according to the third embodiment of the invention, further including a cover; 
     FIG. 10 is an illustration of a semiconductor exposure apparatus; 
     FIG. 11A, FIG. 11B, FIG. 11C, and FIG. 11D are side views showing an operation of an SMIF-type loading port unit for reticles; and 
     FIG. 12A, FIG. 12B, FIG. 12C, and FIG. 12D are side views showing an operation of an FOUP-type loading port unit for wafers. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     &lt;First Embodiment&gt; 
     FIGS. 1A and 1B show a first embodiment of the present invention. FIGS. 1A and 1B are side views showing an operation of a loading port unit included in a semiconductor exposure apparatus shown in FIG.  10 . 
     An outline of the flow of reticles in the semiconductor exposure apparatus is described as follows in conjunction with FIG.  10 . The environment in the semiconductor exposure apparatus is separated from the environment of a clean room by forming a chamber  6  in the clean room, and the condition of the air in the chamber  6  is controlled. Reticles  1  are held in carrier units  2 , which are set in a plurality of loading ports  31  disposed vertically. The reticles  1  are transferred from the carrier units  2  by a reticle transporting mechanism  4  for loading and unloading reticles. Codes on the reticles are read by an identification reading unit  51  for registering and confirming reticle identifications. The reticles  1  are positioned to be aligned with a reticle stage  71  by an alignment station  54 , and then transferred onto the reticle stage  71  for exposure. 
     The semiconductor exposure apparatus shown in FIG. 10 includes an optical projection lens  73 , a wafer stage  72 , and an inspection unit  52  for inspecting surfaces of the reticles  1  to detect dust particles thereon. The semiconductor exposure apparatus also includes a library  53  for storing a plurality of the reticles  1 , provided adjacent to the reticle stage  71 . When the schedule of reticles to be used is known, the reticles  1  can be transported in advance, after the dust particle inspection, to be stored in the library  53 , whereby the time for reticle exchange can be reduced, thereby enabling efficient reticle management. 
     With reference to FIGS. 1A and 1B and FIGS. 2A and 2B, the loading port unit is described in detail as follows. Each reticle  1  is supported in the carrier unit  2  by a reticle supporting member  23 , the aperture of the carrier unit  2  being hermetically sealed by a carrier door  22 . The carrier unit  2  is transported manually or by an automatic transporting mechanism such as an AGV to be set on a loading port  31 . 
     The position of the transported carrier unit  2  on the loading port  31  is corrected by kinematic coupling pins  32 , which are standardized according to the SEMI standard, the carrier unit  2  being brought into contact with the kinematic coupling pins  32  by a clamping mechanism. Each carrier unit  2  is applied by an applying mechanism provided in the loading port  31  to the chamber  6  by translationally moving the kinematic coupling pins  32  and the clamping mechanism to be pushed against an outer wall of the chamber  6 . In this case, a carrier  21  of the carrier unit  2  and the chamber  6  are hermetically connected by a sealing member such as an O-ring provided on the outer wall of the chamber  6 , as shown in FIG.  2 A. 
     The aperture of the chamber  6  is sealed by a chamber door  62 , unless the carrier unit  2  is applied to the chamber  6 . The chamber door  62  includes a lock releasing mechanism  75  for releasing a lock of the carrier door  22  and a supporting mechanism  77 , such as a vacuum chuck for supporting the chamber door  62  together with the carrier door  22 . When the carrier unit  2  is applied to the chamber  6 , the lock of the carrier door  22  is released by the lock releasing mechanism, and the carrier door  22  and the chamber door  62  are supported as a unit by the supporting mechanism. The carrier door  22  and the chamber door  62  are supported so that dust particles of the external environment adhering to the outer sides of the two doors are trapped therebetween. 
     Each carrier door  22  and each chamber door  62 , which are supported as a unit, are removed, while rotating, from the carrier  21  and the chamber  6  by an opening arm  34  supported by an opener  33 , as shown in FIGS. 1A and 2B. Each reticle  1  in the carrier  21  is loaded and unloaded by a transfer handler  41 , as shown in FIG.  1 B. Rotating axes  39 , around which the doors rotate, are disposed on a plane extending from the interface, which is the sealed plane, between the chamber  6  and the chamber doors  62 , thereby enabling the carrier doors  22  and the chamber doors  62  to rotate while being removed smoothly with no sliding movement. 
     A transporting robot  42  is driven in the extending/drawing-back direction of a handling arm thereof and in the rotational direction of the transporting robot  42 . An elevator  43  is a mechanism for lifting the transporting robot  42 . The openers  33  and the opening arms  34  are provided at each loading port  31  so that each carrier unit  2  can independently be opened and closed. Therefore, each of the reticles  1  can be transferred, to be loaded, from the carrier unit  2  immediately after another reticle  1  is unloaded and transferred to another carrier unit  2  by opening the carrier units  2  in advance, whereby the time for transfer can be reduced. 
     In FIGS. 3A and 3B and FIGS. 4A,  4 B, and  4 C, the carrier door  22  and the chamber door  62  may be removed from the carrier  21  and the chamber  6  in the horizontal direction (in FIG.  4 B), and then rotated around a horizontal axis (in FIG.  4 C). With this arrangement, the space required for rotating the doors can be reduced, whereby the distance between the loading ports  31  and the transporting robot  42  can be reduced, thereby providing an advantage in that the footprint of the devices and the movement stroke of the transporting robot  42  can be reduced. 
     The carrier doors  22  and the chamber doors  62  may be rotated to be removed downwardly from the carriers  21  and the chamber  6  when there is a risk of not sufficiently trapping dust particles from the outside of the chamber  6  between the carrier doors  22  and the chamber doors  62 , instead of being rotated to be removed upwardly, according to this embodiment. 
     &lt;Second Embodiment&gt; 
     FIGS. 5A,  5 B, and  5 C, showing a second embodiment according to the present invention, are side views showing an operation of the loading port unit included in the semiconductor exposure apparatus shown in FIG.  10 . 
     Each of reticles  1  is supported by a reticle supporting member  23  in a carrier unit  2 . The aperture of each carrier  21  is hermetically sealed by a carrier door  22 . The carrier units  2  are transported either manually or by a transporting mechanism such as an AGV to be set onto loading ports  31 . 
     The position of each of the transported carrier units  2  on the loading ports  31  is corrected by kinematic coupling pins  32 , which are standardized according to the SEMI standard, the carrier unit  2  being brought into contact with the kinematic coupling pins  32  by a clamping mechanism. Each carrier unit  2  is applied by an applying mechanism provided in the loading port  31  to the chamber  6  by translationally moving the kinematic coupling pins  32  and the clamping mechanism to be pushed against an outer wall of the chamber  6 . In this case, the carrier  21  of the carrier unit  2  and the chamber  6  are hermetically connected by a sealing member such as an O-ring provided on the outer wall of the chamber  6 . 
     The apertures of the chamber  6  are sealed by chamber doors  62 , unless the carrier units  2  are applied to the chamber  6 . Each chamber door  62  includes therein a lock releasing mechanism for releasing a lock of the carrier door  22  and a supporting mechanism such as a vacuum chuck for supporting the chamber door  62  and the carrier door  22  as a unit. When the carrier units  2  are applied to the chamber  6 , the lock of each carrier door  22  is released by the carrier lock releasing mechanism, and the carrier door  22  and the chamber door  62  are supported as a unit by the supporting mechanism. The carrier door  22  and the chamber door  62  are supported so that any dust particles from the external environment adhering on the outer sides of the two doors are trapped therebetween. 
     An opener  35  and an opening arm  36  are provided at a transporting robot  42  side. The opener  35  and the opening arm  36  are vertically driven together with the transporting robot  42 . When the carrier units  2  are applied to the chamber  6 , the transporting robot  42  is lifted by an elevator  43  to the level of a door to be opened or closed, the opener  35  extends the opening arm  36  (in FIG.  5 A), and the opening arm  36  docks with the chamber door  62 . 
     The carrier door  22  and the chamber door  62 , while being supported as a unit, are removed from the carrier  21  and the chamber  6  by the opening arm  36  supported by the opener  35 , as shown in FIG. 5B, and are drawn toward the transporting robot  42  to be held thereby. Then, the transporting robot  42  is moved by the elevator  43  to the level at which the reticle  1  is transferred, and the reticle  1  is transferred from or to the carrier  22  by a transfer handler  41 , as shown in FIG.  5 C. 
     A plurality of the openers  35  and a plurality of the opening arms  36  may be provided at the transporting robot  42  side, whereby a plurality of the carriers  22  can be kept open simultaneously. With this arrangement, each reticle  1  can be transferred, to be loaded, from the carrier unit  2  immediately after another reticle  1  is unloaded and transferred to another carrier unit  2 , thereby reducing transfer time. A plurality of the opening arms  36  may be provided with the same distance therebetween as that between each loading port  31  so that a plurality of the carrier doors  22  and the chamber doors  62  can be opened or closed simultaneously, as shown in FIG.  6 . 
     In the same manner as in the first embodiment, when the schedule of reticles to be used is known, the reticles  1  may be transported in advance to be stored in the library  53 , whereby the time for reticle exchange can be reduced, thereby enabling efficient reticle management. 
     In FIGS. 7A and 7B, the loading port unit according to the second embodiment is applied to the FOUP system. The above-described FOUP-type carrier door  292  and the chamber door  393 , standardized according to the SEMI standard, while being supported as a unit, are removed from the carrier  291  and the chamber  6 , and then vertically moved together with the transporting robot  42 , while being supported at the transporting robot  42  side, for the transfer of substrates. With this arrangement, the loading ports  391  can be disposed to overlap each other, as shown in FIGS. 7A and 7B, because openers provided in known loading port units for downwardly moving doors are eliminated, thereby reducing the footprint of the apparatuses. 
     In the loading port unit according to the invention, the space occupied by the apparatuses can be reduced when a plurality of the loading ports must be horizontally disposed due to limited space in a vertical direction, because the height of the loading ports can be reduced. 
     &lt;Third Embodiment&gt; 
     FIGS. 8A and 8B, showing a third embodiment according to the present invention, are side views showing an operation of the loading port unit included in the semiconductor exposure apparatus shown in FIG.  10 . For the third embodiment, a description of the same parts as those described in the first embodiment is omitted. 
     The loading port unit includes an air-blower mechanism  44  for applying clean air or temperature-controlled clean air to the reticles  1  during transferring. The clean air starts to be applied to the reticles  1  when they are removed or after being removed from the carrier units  2 , and is continuously applied to the reticles  1  while the reticles being removed from the carrier units  2  or while being transferred, as shown in FIG. 8B, whereby the surfaces of the reticles  1  can be kept clean, thereby enabling very reliable dust-particle control. As shown in FIG. 9, the transporting robot  42  may be provided with a cover  45  for covering the reticle  1 , whereby indeterminate factors such as effects of dust particles produced by the moving parts in the chamber can be avoided, thereby enabling a more reliable dust-particle control. 
     According to the first embodiment of the present invention, a plurality of the loading ports can be provided in the vertical direction, and the carrier doors and the chamber doors can be rotatably removed as a unit by the opener, whereby an efficient substrate-transporting system is provided without increasing the footprint of the loading port units. 
     According to the second embodiment of the present invention, a low cost apparatus can be obtained by eliminating the openers provided on the loading ports. The embodiment is most preferably applied to a loading port unit having less than five carrier units, because the number of carriers which can be kept open simultaneously is limited. 
     On the other hand, the same efficient transportation as in the loading port unit having less than five carrier units can be provided in the loading port unit according to the first embodiment, when having more than five carrier units, because the carriers can independently be opened and closed by providing openers on all the loading ports, according to the first embodiment. 
     According to the third embodiment of the present invention, the substrates can be kept clean while being transported, thereby providing a substrate-transportation system having highly reliable dust-particle control. When the substrates to be transported are reticles, the invention contributes to improved exposure-accuracy performance by controlling temperature during the transportation, thereby providing efficient transportation of the reticles. 
     Except as otherwise disclosed herein, the various components shown in outline or in block form in the figures are individually well known and their internal construction and operation are not critical either to the making or using of this invention or to a description of the best mode of the invention. 
     While the present invention has been described with reference to what are presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.