Abstract:
An improved wafer transfer apparatus is provided that allows the ambient atmosphere within a modified front open unified pod (“FOUP”) while the FOUP is positioned on a loading stage provided on an equipment front end module (“EFEM”). In particular, the wafer transfer apparatus includes both an injection assembly and an exhaust assembly that will be engaged when the door of the FOUP is docked to a door holder provided on the EFEM. The injection assembly may include a mass flow controller (“MFC”) for controlling the injection of purge gas(es) into the container. Similarly, the exhaust assembly may include a MFC for controlling the removal of fluid from the container. While the door is docked to the door holder, inert or less reactive gases may be introduced into the container, thereby reducing the likelihood of oxidation or contamination of the wafers therein.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This U.S. nonprovisional patent application claims priority under 35 U.S.C. § 119 from Korean Patent Application 2003-79859, which was filed on Nov. 12, 2003, the entire contents of which are hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to apparatus and method for transporting semiconductor substrates within a clean room and delivering wafers to and receiving wafers from automated process equipment and, more particularly, to an apparatus including a load port for opening/closing a door provided on a container in which semiconductor substrates are loaded and a method for filling the inside of the container with a selected gas or gas mixture to improve the ambient environment to which the wafers are exposed during transport and storage.  
         [0004]     2. Discussion of the Related Art  
         [0005]     Conventional semiconductor manufacturing processes are performed in large clean rooms and commonly use open wafer containers for storing and transferring wafers within the clean room. In recent years, in an effort to reduce the cost of maintaining a large clean room environment, manufacturing facilities have been developed in which a high degree of cleanliness is required only selected areas such as within the process equipment and associated wafer handling operations, while a somewhat lower degree of cleanliness is acceptable in the other parts of the facilities. Sealed wafer containers are typically used to shield the wafers from atmospheric foreign substances or chemical contamination when transferring wafers through those areas maintained at a low degree of cleanliness. A typical example of a sealed wafer container is a front open unified pod (hereinafter referred to as “FOUP”).  
         [0006]     As the diameter of the wafers continues to increase, such as from 200 mm to 300 mm, semiconductor chips are increasing manufactured using automated systems, in part simply due to the weight of the wafers and their container. In order to automate the semiconductor manufacturing process and operate in the clean room environment, an equipment front end module (hereinafter referred to as “EFEM”) is used. The EFEM is connected to a process apparatus for transferring wafers from a FOUP to the process apparatus or vice versa.  
         [0007]     A load port used in such a EFEM facility is disclosed in U.S. Pat. No. 6,473,996. When an FOUP is placed on a station on the load port, the FOUP door is opened by a door opener and wafers are removed from the FOUP for transfer to the process equipment. After the processing has been completed, the processed wafers are then returned to the FOUP, and the FOUP door is closed to seal the wafers within the FOUP before they are removed from the EFEM station and protect them from contamination in the outside environment. Although air flowing into the EFEM is filtered, it will still contain molecular and gaseous contaminants such as oxygen, water and ozone. Thus, these contaminants will be present in the sealed FOUP and may oxidize a wafer surface or bind to the wafer surface in a manner that can interfere with subsequent processing or otherwise lower the final yield of good semiconductor products.  
       SUMMARY OF THE INVENTION  
       [0008]     Exemplary embodiments of the present invention are directed to an apparatus and a method for suppressing formation of a native oxide layer or other defects on a wafer resulting from contaminants within the FOUP. In an exemplary embodiment, the apparatus includes a load port and a container for receiving semiconductor substrates. The container has a door in which at least one inflow hole or inlet port is formed. The load port has a station on which the container may be positioned and a door opener for opening/closing the door. The door opener includes a door holder that may be connected to the door when the container is opened and closed. An injection assembly is disposed on or within the door holder. The injection assembly injects gas through the inflow hole into the container to fill the inside of the container with the gas while the door is connected or docked to the door holder.  
         [0009]     The injection assembly includes an injection port formed and positioned to cooperate with the inflow hole when the door is docked or connected to the door holder. The injection assembly also includes a supply pipe connected to the injection port for supplying the gas to the injection port and may include a mass flow controller installed in the supply pipe. The injection port may also be configured to inject the gas or cause the gas to flow in a direction generally parallel to the semiconductor substrates loaded in the container.  
         [0010]     A filter for preventing or reducing the introduction of external particles into the container and an inflow hole open/close assembly for opening/closing the inflow hole may be inserted into the inflow hole. The inflow hole open/close assembly includes a fixture that is coupled to the flow hole and protrudes inwardly toward the inflow hole, an isolation plate for opening/closing a flow path through the fixture, and an elastic body connected to the isolation plate an arranged to apply force to the isolation plate tending to maintain a closed position. A passage for the gas may be provided at the center of the fixture. The isolation plate may be moved within the fixture by the pressure of the gas supplied from the injection part.  
         [0011]     An outflow hole is formed at the door, and an exhaust assembly is provided at the door holder to provide an exhaust path for fluid exiting the container. The gas in the container may be removed through the outflow hole and the exhaust assembly while the door is docked with the door holder. The exhaust assembly includes an exhaust port that is a hole formed at the door holder, an exhaust pipe connected to the exhaust port, and a pump or other vacuum source connected to the exhaust pipe.  
         [0012]     An outflow hole open/close assembly for opening/closing the outflow hole is provided adjacent the outflow hole. The outflow hole open/close assembly includes a protrusion plate that is connected to the outflow hole and protrudes inwardly toward the outflow hole, an isolation plate for opening/closing a moving plate of the protrusion plate, and an elastic body connected to the isolation plate for applying a force tending to maintain the isolation plate in a closed position. An air passage may be formed through the center of the protrusion plate when the isolation plate is separated from the protrusion plate by a vacuum applied by the pump or pressure within the container.  
         [0013]     The injection port may be formed at one side of the door holder and the exhaust port is formed in another region offset from the injection port. The injection port may comprise a plurality of injection ports disposed at different heights or in a first pattern. A door fixing part may be provided for fixing and maintaining the orientation of door and the door holder while the gas is injected into and/or evacuated from the container. The door fixing part may include vacuum holes formed on the face of the door and/or the door holder through which a vacuum may be applied to hold the relative position of the door and door holder.  
         [0014]     In an exemplary embodiment of the present invention, a substrate processing apparatus includes a container that receives semiconductor substrates and has a door and a handling system that allows the substrates to be transferred between the container and a processing apparatus and has a load port that includes a station on which the container may be positioned. At least one inflow hole and at least one outflow hole are formed through the container door. The load port includes a door holder that provides an injection port for injecting nitrogen gas and/or another inert gas into the container and an exhaust port for exhausting fluid from the container are engaged when the door holder is docked with the door. The nitrogen gas or inert gas injected from the injection port enters the container through the inflow hole of the door while fluid within the container is exhausted through the outflow hole of the door and the exhaust port.  
         [0015]     In an exemplary embodiment of the present invention, a substrate processing method includes docking the door of an empty container arranged on a load port with a door holder separating the door from the container, transferring substrates into the container, resetting the door on the container, and injecting gas into the container through the inflow hole(s) formed in the door to fill the container with a non-reactive gas.  
         [0016]     The step of filling the container with the gas may include both injecting the gas into the container from the injection port through the inflow hole and simultaneously exhausting fluid from the container through an outflow hole formed at the door and a second step of closing the outflow hole and injecting additional gas into the container from the injection part through the inflow hole to fill the inside of the container with the gas. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The features and advantages of the present invention are described with reference to exemplary embodiments in association with the attached drawings in which similar reference numerals are used to indicate like or corresponding elements and in which:  
         [0018]      FIG. 1  is a cross-sectional view of a substrate treating apparatus according to an exemplary embodiment of the present invention;  
         [0019]      FIG. 2  is a perspective view of an FOUP shown in  FIG. 1 ;  
         [0020]      FIG. 3  is a perspective view of a load port shown in  FIG. 1 ;  
         [0021]      FIG. 4  is a front view of an FOUP door;  
         [0022]      FIG. 5  is a schematic diagram of a door opener;  
         [0023]      FIG. 6  is a front view of a door holder at which a vacuum hole is formed;  
         [0024]      FIG. 7  is a cross-sectional view of a portion where an inflow hole is formed at the FOUP door;  
         [0025]      FIG. 8  and  FIG. 9  are cross-sectional views showing the states that the inflow hole of the FOUP door is opened and closed, respectively;  
         [0026]      FIG. 10  is a cross-sectional view of a portion where an outflow hole is formed at the FOUP door;  
         [0027]      FIG. 11  and  FIG. 12  are cross-sectional views showing a flow path of gas in the FOUP, respectively;  
         [0028]      FIG. 13  is a flowchart of a substrate treating method according to an exemplary embodiment of the present invention;  
         [0029]      FIG. 14  through  FIG. 16  are cross-sectional views showing the steps of filling the inside of the FOUP with gas; and  
         [0030]      FIG. 17  is a cross-sectional view showing an example that the substrate treating apparatus according to the present invention is connected to a cleaning facility. 
     
    
       [0031]     These drawings have been provided to assist in the understanding of the exemplary embodiments of the invention as described in more detail below and should not be construed as unduly limiting the invention. In particular, the relative spacing, positioning, sizing and dimensions of the various elements illustrated in the drawings are not drawn to scale and may have been exaggerated, reduced or otherwise modified for the purpose of improved clarity. Those of ordinary skill in the art will also appreciate that certain alternative fixtures and mechanisms that may be commonly utilized in the operation of FOUP and EFEM structures, have been omitted simply to improve the clarity and reduce the number of drawings.  
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0032]     As illustrated in  FIG. 1 , a substrate treating or processing device  1  includes a container  100 , a wafer handling system  20 , and a purge part ( 500  of FIG.  5 ). The container  100  is a receptacle configured for receiving semiconductor substrates such as silicon wafers and will typically be a front open unified pod (hereinafter referred to as “FOUP”). The FOUP is a sealable wafer carrier used for shielding wafers from atmospheric and/or chemical contamination while transferring wafers between processing equipment and or storage areas.  
         [0033]     As illustrated in  FIG. 2 , the FOUP  100  may include a front-opening body  120  and a door  140  for opening/closing the front of the body  120 . Parallel slots  160  are typically formed on the inner walls of the body  120  for supporting and separating wafers within the FOUP. The slots  160  may be substantially perpendicular to a plane defined by the door  140 .  
         [0034]     The wafer handling system  20  can be used to transfer wafers from the FOUP  100  to the process equipment or process apparatus  700  or vice versa. The wafer handling system  20  may include a housing  300 , a load port  200 , a cleaning part  600 , and one or more transfer robots  660 . The process apparatus  700  may be, for example, a chemical vapor deposition (CVD) apparatus, a dry etch apparatus, a thermal furnace, a developing apparatus or a cleaning apparatus. The housing  300  will typically include a carry-in or pass-through port  322  formed in a rear wall for transferring a wafer out of the housing and into and out of process apparatus  700  and another opening formed in the front wall  340  for transferring the wafers into and out of the FOUP  100 .  
         [0035]     The cleaning part  600  may be disposed in an upper portion in the housing  300  so as to maintain the inside of the housing  300  at the desired level of cleanliness. The cleaning part  600  may include a fan  640  and a filter  620 . The fan  640  will typically move air downwardly through the housing  300  in a laminar flow with the filter  620  removing particles from the air before it enters the housing. An exhaust port  360  for exhausting the air may be provided at a bottom of the housing  300 . The air may be naturally exhausted or forcibly exhausted using a pump or a blower (not shown). The transfer robot  660 , used for extracting wafers from and returning wafers to the FOUP  100  and moving the wafers into and out of to the process apparatus  700  and may be controlled by a controller  680 .  
         [0036]     As illustrated in  FIG. 3 , the load port  200  may include a substantially vertical frame  220 , a pedestal  240 , a station  260 , and a door opener ( 400  of  FIG. 1 ). The vertical frame  220  can be inserted into an opening provided in the front wall  340  to seal the inside of the housing  300  from the outside environment. The pedestal  240  is coupled to a lateral side of the vertical frame  220 . A through-hole ( 222  of  FIG. 1 ) may be positioned in the vertical frame  220  to accommodate the door  140  when a FOUP  100  is placed on the pedestal  240 . A station  260  is provided on the pedestal  240  for receiving the FOUP  100  and may include plurality of kinematic pins  262 . When the FOUP  100  is placed on the station  260 , the kinematic pins  262  are inserted into corresponding grooves or recesses (not shown) provided on the bottom of the FOUP  100  positioned on the station  260 .  
         [0037]     The door opener  400  can then be employed to open and close the door  140  of the FOUP  100  placed on the station  260 . As illustrated the door opener  400  may include a door holder  420 , an arm ( 440  of  FIG. 1 ), and a driving mechanism (not shown). The door holder  420  can have the same general configuration as the through-hole  222  and may be inserted into the through-hole. The arm  440  will typically be connected to a rear side of the door holder  420  and driven by means of a driving mechanism mounted in the pedestal  240 .  
         [0038]     Latch keys  422  and registration pins  424  are provided on the door holder  420 . The registration pins  424  aid in the precise positioning of the FOUP  100  to align the door  140  to the door holder  420  and the latch keys  422  that may be provided on both sides of the door holder  420 . Referring to  FIG. 4 , registration pin holes  144  and latch key holes  142  are formed on the door  140 . The registration pins  424  are inserted into the corresponding registration pin holes  144 , and the latch keys  422  are inserted into the corresponding latch key holes  142 .  
         [0039]     When a FOUP  100  is placed on the station  260  and moved toward the door holder  420  exposed in the through-hole of the vertical frame  220 , the registration pins  424  will slide into the registration pin holes  144  and determine the docking position between the door  140  and the door holder  420 . The latch keys  422 , which are simultaneously inserted into the corresponding latch key holes  142 , are then rotated to dock or secure the door  140  to the door holder  420 . The arm  440  will typically be connected to a rear side of the door holder  420  and may be moved in up-and-down and forward-and-backward directions by means of the driving part mounted in the pedestal  240 . When the door  140  is opened, i.e., removed, from the FOUP  100 , the arm  440  allows the door holder  420  to move backward a predetermined distance and then downward to a level typically below the level of the through-hole  222 , separating the door  140  from the body  120  of the FOUP  100  and allowing access to the interior of the container. When wafers have been placed into the FOUP  100  by the transfer robot  660 , the door holder  420  can reverse its movements and move upward and forward to connect or reset the door  140  on the body  120  of the FOUP.  
         [0040]     Before the door  140  is closed, air present in the housing  300  may and typically will enter the FOUP  100 . Although most particles may have been removed by the filter  620 , the air in the housing  300  may still contain molecular contaminants such as oxygen, water and ozone. If the FOUP  100  is sealed while such molecular contaminants remain in the container, a native oxide layer or other defects may be formed on wafers loaded in the FOUP.  
         [0041]     In order to prevent formation of the native oxide layer, the purge part  500  exhausts fluid from the FOUP  100  and fills the inside of the FOUP  100  with selected gas such as nitrogen, dry air, or an inert gas such as Ar or Xe. As illustrated in  FIG. 5 , the purge part  500  may include an injection part  520  for injecting nitrogen or other gas into the FOUP  100  and an exhaust part  540  for exhausting fluid from the FOUP. The injection part  520  and the exhaust part  540  are disposed at the door holder  420 . The injection part  520  can include an injection port  522  and a supply pipe  524  while the exhaust part  540  can include an exhaust port  542  and an exhaust pipe  544 .  
         [0042]     The injection port  522  may be a hole formed at one edge portion of the door holder  420  while the exhaust port  542  may be a hole provided in another edge portion offset from the injection port. The injection port  522  may include a plurality of injection ports that may be positioned at different heights. Similarly, the exhaust port  542  may include a plurality of exhaust ports, with the number of exhaust ports tending to equal to that of the number injection ports, and may be positioned at the same or different heights than the injection ports. The positions of the injection port(s)  522  and the exhaust port(s)  542  may be arranged to enable the nitrogen or other purge gas to flow into the FOUP  100  under conditions that will produce turbulent flow and/or laminar flow within the container.  
         [0043]     A supply pipe  524  may be connected between one or more nitrogen or other purge gas source  528  and the injection port  522  while an exhaust pipe  544  may be used to connect pump  548  to the exhaust port  542 . Both the supply pipe  524  and the exhaust pipe  544  may be made of stainless steel, plastic or other suitable material(s) such that the door holder  420  may be repositioned by the arm  440  while maintaining the gas connections. Mass flow controllers (MFCs)  526  and  546  may be provided on the supply pipe  524  and the exhaust pipe  544 , respectively. The MFC  526  may be used to control the amount of nitrogen or other gas(es) supplied to the injection port  522 , and the MFC  546  may be used to control the amount of gas removed from the container. Optionally, pipes may be inserted into the injection port  522  and/or the exhaust port  542 .  
         [0044]     When the FOUP door  140  is separated from the FOUP body  120 , the latch key  422  of the door holder  420  is inserted into the latch key hole  142  of the door  140 , thereby docking the door  140  to the door holder  420 . A door fixing part is provided to prevent the FOUP door  140  from swinging while the nitrogen or other purge gas is injected into the FOUP  100 . The door fixing part may fix the FOUP door  140  to the door holder  420  by means of vacuum. As illustrated in  FIG. 6 , one or more vacuum holes  426  may be formed on the face of the door holder  420 . A vacuum pipe (not shown) is connected to the vacuum hole  426 ( s ) to establish a connection to a vacuum pump (not shown) and allow a vacuum to be applied to the door  140  surface adjacent the vacuum holes.  
         [0045]     An inflow hole  146  may be provided through the door  140  to enable the nitrogen or other purge gas injected from the injection port  522  to flow into the FOUP  100 . The inflow hole  146  is positioned to align and cooperate with the injection port  522  when the door  140  is docked to the door holder  420 .  
         [0046]     As illustrated in  FIG. 7 , a filter  160  and an inflow hole close/open part  180  may be arranged within the respective inflow holes  146 . The filter  160  will tend to reduce or prevent particles from flowing into the FOUP  100  through the inflow hole  146 . The inflow hole close/open part  180  opens and closes a passage for the gas through the FOUP door  140 . The inflow hole open/close part  180  opens the inflow hole  146  while the gas is injected and closes the inflow hole  146  when the gas injection has been completed.  
         [0047]     The inflow hole  146  may be circular with a protrusion  147  formed at the rear end of the inflow hole  146 . The inflow hole open/close part  180  may include a fixture  184 , a protrusion plate  182 , an isolation plate  186  and an elastic body or spring element  188 . The protrusion plate  182  may be a circular plate having a central through-hole  189   b  arranged to cooperate with the protrusion  147 . The fixture  184  may be generally cylindrical and include a side plate  184   a  and an outer or upper plate  184   b . The side plate  184   a  will generally adhere and conform closely to a sidewall of the inflow hole  146  and extend from the edge of the protrusion plate  182  to the front end of the inflow hole  146 . The upper plate  184   b  has a through-hole  189   c  formed at its center. These through-holes  189   a ,  189   b  and  189   c  cooperate to provide a passage for the gas into the container and may have the same size general and shape.  
         [0048]     The isolation plate  186  will typically be configured to open/close the through-hole  189   c  and will typically be disposed in a space  183  within the fixture  184  and the protrusion plate  182 . The isolation plate  186  may be a circular plate that is both wider than the through-hole  189   c  and narrower than the internal space defined by the side plate  184   a . The elastic body or spring element  188  applies a force to the isolation plate  186  that will tend to force it against an inner surface of upper plate  184   b . One end of the elastic body  188  may be coupled to a fix pin or other retainer  187  installed on the rear surface of the isolation plate  186  with the other end being coupled to a fix pin or other retainer  185  provide on an inner surface of the protrusion plate  182 . Alternatively, the elastic body may be allowed to “float” within the space  183 . The elastic body  188  may include a series of springs disposed at regular intervals around the periphery of the isolation plate  186  or may be a single spring or elastomeric element. When the isolation plate  186  is seated against the upper plate  184   b  of the fixture  184 , the elastic body  188  should be in an equilibrium or slightly compressed state to maintain the closed position.  
         [0049]     The open and closed states of the inflow hole  146  of the door  140  are illustrated in  FIG. 8  and  FIG. 9 , respectively. As illustrated in  FIG. 8 , when the gas is supplied at a sufficient pressure above the pressure within the container from the injection port  522 , the elastic body  188  will be compressed and the isolation plate  186  will move backward from the upper plate  184   b  of the fixture  184 . The pressurized gas will then flow into the inflow hole  146  through the opening formed between the isolation plate  186  and the upper plate  184   b  of the fixture  184 . Afterwards, the gas will flow along the through-hole  189   b  of the protrusion plate  182 , the filter  160  and the through-hole  189   a  of the protrusion  147 . When the applied pressure of the gas is reduced, the isolation plate  186  will tend to move forward as a result of the force applied by the spring  188 . When the pressure differential drops below a certain level, the isolation plate will again be seated against the upper plate  184   b  to close the gas passage through the inflow hole  146 , as shown in  FIG. 9 .  
         [0050]     Before the atmosphere inside the FOUP  100  is converted to nitrogen or other purge gas, the fluid originally in the FOUP  100  (typically the air in the FOUP  100  and oxygen, water or other compound(s) carried by a wafer) must be removed. The fluid in the FOUP  100  may be removed through the exhaust part  540  provided in the door holder  420 . For this, an outflow hole  148  in formed at the door  140 . The outflow hole  148  is disposed to align with the exhaust port  424  when the door  140  is docked with the door holder  420 .  
         [0051]     A filter  170  and an outflow hole open/close part  190  may be inserted into the outflow hole  148 . The filter  170  prevents contaminants from flowing into the FOUP  100  through the exhaust part  540 . The outflow hole open/close part  190  opens and closes a passage through the outflow hole  148  through which the fluid remaining in the FOUP  100  may be exhausted or vented. The outflow hole open/close part  190  opens the outflow hole  148  while the fluid in the FOUP  100  is being exhausted, and then closes the outflow hole  148  to maintain the ambient of nitrogen or other purge gas(es) that were introduced into the FOUP  100  through the inflow hole.  
         [0052]     As illustrated in  FIG. 10 , the outflow hole  148  may have the same general configuration as the inflow hole  146 . The shape and position of the filter  170  inserted into the outflow hole  148  may be identical to those of the filter  160  inserted into the inflow hole  146 . Further, the outflow hole open/close part  190  may have the same shape of fixture  194 , protrusion plate  192 , isolation plate  196  and elastic body  198  as those described above for the inflow hole open/close part  180 . The connecting positions of the isolation plate  196  and the elastic body  198  will, however, be reversed from that of the isolation plate  186  and the elastic body  188 . The isolation plate  196  is disposed to face the protrusion plate  192 , as shown in  FIG. 9 . One end of the elastic body  198  may be connected to a fix pin or other retainer  195  installed at the front edge of the isolation plate  196 , with the other end being similarly connected to a fix pin or other retainer  195  installed at the upper plate  194   b  of the fixture  194 .  
         [0053]     When the pump  548  of the exhaust part  540  is activated and reduced the pressure applied to the backside of the isolation plate  196  below that of the interior of the container  120 , the isolation plate will tend to move backward as a result of this pressure differential and be spaced apart from the protrusion plate  192  as the elastic body  198  is compressed. The fluid in the FOUP  100  will then be exhausted, vented or otherwise removed through a space  193  made between the protrusion plate  192  and the isolation plate  196  and a through-hole  199   c  formed at the upper plate  194   b  of the fixture  194 . When the operation of the pump  548  is terminated, the isolation plate  196  will move forward as a result of the elastic force of the elastic body  198  to reseat against the protrusion plate  192  and close the fluid passage through the inflow hole  148 .  
         [0054]     As illustrated in  FIG. 11  and  FIG. 12 , the injection part  520  is disposed at the door holder  420 . The nitrogen or other purge gas injected from the injection part  520  may be injected into the FOUP  100  through the inflow hole  146  formed at the door  140  in a direction parallel with the primary wafer surfaces. Thus, water and oxygen attached to surfaces of wafers may be removed more rapidly and completely.  
         [0055]     According to an exemplary embodiment of the present invention, the interior of the FOUP  100  may be converted to a nitrogen-ambient almost immediately after loading the wafers into the FOUP. This is because a native oxide layer may be formed on a wafer when the atmosphere within the FOUP  100  is not converted to a nitrogen or other inert gas ambient while transporting or storing the FOUP before the next processing step.  
         [0056]      FIG. 13  is a flowchart of an exemplary substrate treating method according to an embodiment of the present invention, and  FIGS. 14-16  are cross-sectional views showing the steps of filling the inside of the FOUP with nitrogen or other purge gas. An empty FOUP  100  is placed on a stage  260  of a load port, and the door  140  is docked to a door holder  420  (step S 10 ). The door  140  is opened, and the door holder  420  and the door  140  are moved out of the way to allow access to the interior of the body  120  of the FOUP  100  (step S 20 ). Processed wafers are then loaded into the FOUP using a transfer robot  660  or other device (step S 30 ). When the wafers are loaded in the FOUP  100 , the door holder  420  is activated to return the door  140  to the FOUP  100  (step S 40 ). While the door  140  moves, nitrogen or another purge gas is injected and the pump  548  operates, as shown in  FIG. 14 . An inflow hole  146  formed at a door  140  is opened by an increased external gas pressure, and an outflow hole  148  formed at the door  140  is opened by a reduced external (vacuum) pressure. The nitrogen gas may be injected into the FOUP  100  in a direction parallel to the wafer surfaces to aid in removing attached particles and/or water. The fluid remaining in the FOUP  100  is exhausted through the outflow hole  148  and an exhaust pipe  540  (step S 54 ). When the door  140  is connected to the FOUP  100  to close the FOUP, the operation of the pump  548  may be stopped and the outflow hole  148  may be closed. Alternatively, after the door  140  is closed, additional nitrogen gas may be injected into the FOUP  100  and the fluid in the FOUP may be exhausted for a predetermined time. As shown in  FIG. 16 , the inside of the FOUP  100  is converted to a nitrogen or other generally inert gas ambient by gas supplied through injection port  522  (step S 54 ). After a predetermined period of time, the gas injection may be stopped and the inflow hole  146  formed at the door  140  may be closed.  
         [0057]     While the exemplary embodiment has been described with the nitrogen gas being injected while the door  140  moves toward the FOUP  100 , the nitrogen gas may be injected after the door  140  is connected to the FOUP  100 .  
         [0058]     In  FIG. 17 , a solid-line arrow indicates a transportation path of the FOUP  100 , and a dotted-line arrow indicates a transfer path of a wafer. In a clean apparatus, a cleaning process may be carried out in a series of baths  860  are disposed in a line. An EFEM  820  is disposed at one side of the respective baths  860 , and another EFEM  840  is disposed at the other side thereof. To make the inside of the FOUP  100  loading completely cleaned wafers therein nitrogen-ambient, the EFEM  840  disposed at the other side of the respective baths  860  may include the purge part  500  detailed above or an equivalent structure.  
         [0059]     After being carried into the cleaning apparatus  800 , the wafer-loading FOUP  100  is loaded to the load port  824  of the EFEM  820  disposed at the entry side of the baths  860  by means of a transfer part  882 . By means of a transfer robot, the wafers in the FOUP  100  are then transferred to the bath  860  and a vacant FOUP  100  is transported to the load port  844  of the EFEM  840  disposed at the exit side of the baths  860 . The wafers are cleaned in the baths  860 . The cleaned wafers are transferred into the FOUP  100  placed at the load port  844  of the EFEM  840 . When the wafers are loaded in the FOUP  100 , the nitrogen gas is injected to make the inside of the FOUP  100  nitrogen-ambient. The wafers are then carried out from the semiconductor manufacturing apparatus by means of a transfer part  866 .  
         [0060]     While exemplary embodiments of the present invention have been shown and described in detail, the foregoing description is illustrative only and should not be interpreted as unduly limiting the scope of the invention. It is therefore understood that various modifications and substitutes may be made without departing from the scope of the invention.