Closed container and lid opening/closing system therefor

In a pod used in an FIMS system, diffusion of dust particles or the like adhering on the lid of the pod to the interior of the system is reduced. An engaged portion is provided inside the outer surface of the lid of the pod, and a flange portion provided around a pod opening to which the lid can be fitted is provided with an insertion hole that allows access to the engaged portion from the exterior space. A latch mechanism is supported on the pod body side surface of the flange portion in such a way that the latch mechanism can slide along a direction parallel to the side wall of the flange. An engagement portion of the latch mechanism reaches the engaged portion through the insertion hole, and the state of the latch mechanism changes between an engaged state and a disengaged state with movement of the latch mechanism.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to what is called a FIMS (Front-Opening Interface Mechanical Standard) system that is used when wafers stored in the interior of a transfer container called a pod between semiconductor processing apparatuses in a semiconductor manufacturing process etc. More specifically, the present invention relates to a pod called a FOUP (Front-Opening Unified Pod) or a closed container for containing wafers and a lid opening/closing system as a FIMS system for opening/closing the lid of the pod to perform transfer of wafers into/out of the pod.

2. Related Background Art

In semiconductor manufacturing processes performed in recent years, only the interior of a processing apparatus, the interior of a pod (storage container for wafers) and a mini-environment through which transfer of substrates or wafers from the pod to the processing apparatus is performed are kept in a highly clean state, and the degree of cleanness of the other spaces is maintained at a certain level. The pod is composed of a substantially cubical body having shelves provided therein that can hold a plurality of wafers in a parallel and separated state and an opening provided on one side thereof through which wafers can be brought into/out of it, and a lid for closing the opening. Those pods which have an opening provided not on the bottom but on one lateral side thereof (i.e. the side to be directly opposed to the mini-environment) are collectively called FOUP.

A structure that defines the above mentioned mini-environment has a opening portion to be opposed to the opening of the pod, a door that closes the opening portion, another processing apparatus side opening portion provided on the semiconductor processing apparatus side of the structure, and a transferring robot that is adapted to reach into the interior of the pod through the opening portion to pick up a wafer and transfer it into the processing apparatus through the other opening portion on the processing apparatus side. The structure that defines the mini-environment further has a support table that supports the pod in such a way that the pod opening is placed just in front of the door. On the top surface of the support table are provided positioning pins to be fitted into positioning holes provided on the bottom surface of the pod to regulate the placement position of the pod and a clamp unit for engaging a clamped portion provided on the bottom surface of the pod to fix the pod to the support table. Typically, the support table is adapted to be movable toward and away from the door over a predetermined distance. When the wafers in a pod are to be transferred into the processing apparatus, the pod placed on the support table is moved until the lid of the pod abuts the door, and then after abutment, the lid is detached from the opening of the pod by the door. By these operations, the interior of the pod and the interior of the processing apparatus are bought into communication with each other through the mini-environment to allow wafer transferring operations that will be performed repeatedly. All of the support table, the door, the opening portion, a mechanism for opening and closing the door and a wall partly defining the mini-environment and having the opening collectively constitute what is called a FIMS system mentioned above.

The lid of a conventional pod is provided, for example, with tongues that are extendable/retractable outwardly beyond/into the outer periphery of the lid so that the pod body and the lid are brought into an engaging state and a disengaged state by extension and retraction of the tongues, as described in detail in Japanese Patent Application Laid-Open No. 2001-077177. Extension and retraction of the tongues are performed by fitting a so-called key member into an operated portion that is linked with the tongues and disposed at a certain position in the central area of the lid, from the outside of the front surface of the lid. Such contact, rotation and sliding etc. of this member generate dust that should be generally taken care of in the semiconductor manufacturing process. However, the dust is brought into the mini-environment in which downward air flow is present before diffused from the small gap between the surface of the lid and the surface of the door to the exterior of the gap. Therefore, the amount of dust diffused into the mini-environment or the pod is not so much that it is regarded as problem, and no countermeasure to such dust has been taken.

The pod is transferred in a space in which the degree of cleanness is relatively low. Therefore, dust adheres to the outer surface of the pod body and to the surface of the lid in that space, and substances, such as for example hydrocarbon, contained in the atmospheric air is adsorbed on these surface. It has been considered that such dust and substances are also favorably removed by the effect of downward air flow as with the above-described dust generated by the key member etc.

Improvement in the performance of semiconductor devices and reduction in the size of semiconductor devices have be progressively made. Accordingly, the width of wiring and design rules etc. used in devices have been narrowed, and it has become necessary to take care of smaller size dust particles that did not matter before. Such very small dust particles move in a space due to Brownian motion or influence of weak electrostatic forces. Such motions of very small dust particles are different from those of the dust particles for which countermeasures have conventionally been taken. More specifically, even if the above described downward air flow is supplied with a view to move such very small dust particles down in the mini-environment and to expels them to the exterior space, there is a possibility that dust particles are not simply moved by the air flow but float into the mini-environment. Japanese Patent No. 3417821 discloses a structure in which swing levers are provided outside the opening of the pod instead of tongues provided on the lid, and the lid is pressed down by the levers from the outer surface side of the lid in the state in which the opening is closed by the lid. In this structure, dust like that generated by the key member in the structure disclosed in Japanese Patent Application Laid-Open No. 2001-077177 is generated in the periphery of the opening, and diffusion of dust from the lid and the door that holds the lid may be reduced as compared to the structure disclosed in Japanese Patent Application Laid-Open No. 2001-077177. However, since it is necessary to operate the levers in advance before the operation of opening/closing the lid, and the structure for this operation is provided in the vicinity of the opening, there is a possibility that very small dust particles existing in the outer space are diffused into the mini-environment.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above described situations, and has as an object to provide a pod or a closed container in which influence of very small dust particles adhering to the surface of a lid that closes the opening of the pod is controlled and generation of dust by the operation of opening/closing the lid upon opening/closing the lid and diffusion of the dust thus generated into a mini-environment and the interior of the pod are controlled, and to provide a lid opening/closing system associated with such a closed container.

To achieve the above object, according to the present invention, there is provided a closed container comprising: a lid having a flat plate-like shape and having an engaged portion provided in the flat plate-like shape; a container body having an interior space in which an object can be stored, an opening that allows communication between the interior space and the external space and is to be closed by one side of the flat plate-like shape of the lid, a flange portion that extends from the periphery of the opening parallel to a surface on which the opening is formed and defines a receiving recess in which the lid is received in a state in which the opening is closed by the lid and an insertion hole that passes from an outer surface of the flange portion to the receiving recess and is provided at a position aligned with the engaged portion in a state in which the lid is received in the receiving recess; and a latch mechanism having a latch main body that is movable along an axis parallel to the surface on which the opening is formed and extends in the direction of the axis, a link portion that projects from the latch main body in a direction different from a direction along the axis and an engagement portion disposed at an end of the link portion, wherein at least the engagement portion reaches the receiving recess through the insertion hole, the engagement portion engages the engaged portion of the lid disposed in the receiving recess, and engagement of the engagement portion and the engaged portion and release of the engagement are achieved by movement of the latch main body along the axis.

In the closed container described above, it is preferred that the engaged portion have an L-shape including a first straight portion that extends along a direction in which the outer peripheral surface of the flat plate-like shape extends, and a second straight portion that extends along the thickness direction of the lid and has an open end on one side of the flat plate-like shape, and the engagement portion is capable of engaging an inner wall that defines the first straight portion of the L-shape, and the engagement is released when the engagement portion is moved into the second straight portion by movement of the latch main body along the axis. In this case, it is also preferred that the first straight portion and the second straight portion in the engaged portion constitute a recess that opens on an outer peripheral surface of the flat plate-like shape. It is also preferred that the inner wall have a shape of at least one of an undulated surface and an inclined surface that causes a biasing force that the engagement portion exerts on the inner wall to change as the engagement portion moves toward an end of the first straight portion that is different from an end at which the first straight portion joins with the second straight portion. It is also preferred that the engagement portion have a disk-like roller that can roll while in contact with the inner wall. Furthermore, it is preferred that the latch mechanism further comprise biasing means for exerting, to the engagement portion, a biasing force that retains the engagement portion stationary at a position at which the engagement portion engages the engaged portion. It is also preferred that the latch main body further comprise a slide rail that supports the latch mechanism in such a way that the latch mechanism is movable along the axis, and the slide rail be disposed on a surface of the flange portion on the container body side.

To achieve the above described object, according to the present invention, there is provided a lid opening and closing system that opens and closes the lid of a closed container according to claim1to allows the object to be brought into/out of the interior of the closed container, comprising: a mini-environment having an opening portion; a door that can move between a position at which it substantially closes the opening portion and a position at which it leaves the opening portion open; and a latch mechanism drive means that can operate the latch mechanism when the closed container is at a position at which opening and closing of the lid by the door is performed, the latch mechanism drive means being disposed in the vicinity of the opening portion. In this lid opening and closing system, it is preferred that the latch mechanism drive means comprise a rod that is disposed coaxially with the axis, which is an axis of movement of the latch main body, and capable of pushing the latch mechanism along the axis of movement, and an actuator that supports the rod in such a way as to be capable of extending and retracting the rod along the axis of movement. It is also preferred that the lid opening and closing system further comprise a container support table that moves the closed container toward or away from the opening portion in a state in which the closed container is placed thereon, wherein the latch mechanism drive means comprises a cam mechanism including a cam surface that is movable relative to the container support table with movement of the container support table and cam means that is disposed on the container support table and follows the cam surface, the cam mechanism exerting a pushing force on the latch mechanism in accordance with a change in the cam surface caused by movement of the container support table. Furthermore, it is also preferred that the lid opening and closing system further comprise a flange cover that covers an outer peripheral surface of the flange portion when the closed container is at a position at which the lid is opened and closed.

According to the present invention, in the state in which the lid is fixed on the pod, the surface of the lid is flat. In addition, the lid does not have a movable member that is to be accessed and operated from the outside. Therefore, generation of dust with operation of a so-called latch tongue on the front surface of the door, which conventional systems have, can be completely eliminated. In addition, the lid is a simple flat plate-like member that does not have structures provided in the interior thereof, unlike with conventional lids.

Therefore, dust or the like can easily be removed by cleaning. In addition, dust particles or the like do not adhere on the lid in a manner that removal thereof is difficult, and the degree of cleanness of the lid alone can be maintained high. Specifically, since the engaged recess provided on the lid has a simple groove shape, machining and cleaning of the lid is much easier than conventional lids. Change of the diameter of wafers used in semiconductor manufacturing process from 300 mm (the diameter of currently used wafers) to 450 mm have been considered. In pods that store such large-diameter wafers, it is required, with an increase in the size of the lid, to prevent deformation such as warpage and bending of the lid and to fix the lid reliably with adequate strength in fixation. The lid of the pod according to the present invention has a simple flat plate-like structure, and therefore the lid can easily be made light in weight, and the structure that adds rigidity of the lid while achieving a decrease in the weight can be used. Thus, such requirements can easily be met with reliability.

According to the present invention, it is also possible that the lid be adapted to be always biased in the direction for sealing the pod opening in the state in which the lid is fixed on the pod body. This enables improvement in the air tightness of the pod and reduction of possibility of dust generation due to vibration of the lid during transferring etc. Furthermore, since the surface of the lid can be made flat, a seal member may be provided on the lid or the surface of the door opposed thereto to isolate the space defined between the lid and the door from the surrounding space. Thus, diffusion of dust or air coming from the outer space that the lid has brought into the mini-environment is prevented with reliability. In addition, by reducing the pressure in the closed space formed between the lid and the door by the seal member, additional holding of the lid by the door can be provided besides holding of the lid by suction. Furthermore, means for opening and closing the lid is disposed and operates basically in the region outside the pod and the mini-environment. Therefore, if dust is generated from this means, frequency of diffusion of such dust into the pod or the mini-environment is greatly reduced as compared to conventional systems.

In the present invention, what is called a latch mechanism for fixing the lid to the pod may be adapted to be driven in the vertical direction and fixation of the lid is designed to be achieved at a lower position. In this case, fixation of the lid to the pod is achieved by the latch mechanism's own weight. Thus, even when an operation error occurs in the means for driving the latch mechanism upon opening or closing the lid, the latch mechanism can be kept in the position for fixing the lid. Thus, the lid can be kept closed, and the interior space of the pod can continue to be kept clean. In the structure disclosed in Japanese Patent Application Laid-Open No. 2001-077177, for example, in a situation in which the key member and the operated portion of the latch mechanism can hardly be separated due to, for example, erroneous engagement, it may be necessary, for example, to disassemble the lid in order to separate them. In the case of the container according to the present invention, access to the latch mechanism can be made from the external space outside the mini-environment (e.g. from the lateral side of the pod) to forcibly cause the latch mechanism to operate. Therefore, if the latch mechanism becomes inoperable by malfunction, it is possible to repair the trouble relating to the latch mechanism easily by performing the forcible operation. Furthermore, whether the latched state has been appropriately established or not can easily be checked from outside with eyes without providing additional means or operation.

In the present invention, in the drive mechanism for operating the latch mechanism, the size of an operation portion (i.e. drive contact surface that will be described later) for operating the latch mechanism may be arbitrarily designed. Therefore, the degree of accuracy in the position at which the pod is kept when the lid is opened by the door may be lower than in the case of conventional systems. In the case of conventional systems, detachment of the lid from the pod and establishment of communication between the interior space of the pod and the mini-environment cannot be performed unless a high degree of accuracy is achieved in all of the fixed position of the lid relative to the placement position, the fixed position of the pod relative to the opening portion and the position of contact of the door to the lid determined by the latch mechanism. According to the present invention, at least requirement for accuracy of the fixed position of the lid and pod determined by the latch mechanism is relaxed, which advantageously leads, for example, to a simplification of the operation program of the lid opening and closing apparatus and stability of operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, an embodiment of the present invention will be described with reference to the drawings.FIG. 1Ais a perspective view of a pod as an embodiment of the closed container according to the present invention and a FIMS in the form of a lid opening/closing system in a state in which the pod is placed at a position at which the lid is to be closed or opened.FIG. 1Bis an enlarged view of region1B inFIG. 1Ashowing the engagement of a roller portion of a latch mechanism, which will be described later, in the state as shown inFIG. 1A.FIG. 2is a schematic perspective view of the lid of the pod.FIG. 3is a schematic perspective view of the body of the pod.FIG. 4is a schematic perspective view of the latch mechanism fixed on the pod body.FIG. 5Ais a side view of a support table and a wall in which an opening portion of a mini-environment is provided.FIG. 5Bis a front view of them as seen from the side on which the pod is disposed.

The pod1as a closed container according to the present invention is composed of a pod body2as a main body of the container, a lid3and a latch mechanism5attached to the pod body2in a slidable manner. The pod body2is of a substantially cubical shape and has an interior space in which a plurality of contents such as wafers are stored one above another along the vertical direction. The pod body may have various shapes in which wafers can be stored. However, the basic shape of the pod is a cubical shape, and in this sense we describe it as a substantially cubical shape in this specification. The pod body2has an opening2aallowing communication with the storage space on one side face of the substantially cubical shape. The opening2aallows communication between the above described interior space and the exterior space. On the aforementioned lateral side is also provided a flange portion2cthat extends outwardly from the periphery of the opening2ain a plane parallel to an opening plane that contains the opening2ain such a way as to surround the periphery of the opening2a. The flange portion2chas a lateral end surface that is parallel to the aforementioned side face. The lateral end surface is to be opposed to a wall having an opening of a load port serving as a lid opening/closing system that will be described later. The flange portion2chas a thickness larger than the thickness of the lid3. The flange portion2chas a receiving recess2dinto which the lid3is to be fitted when the opening2ais closed by a flat surface (rear surface3athat will be described later) of the lid3having a flat plate-like shape. Thus, the lid3is received in the receiving recess2dwhen the opening2ais closed by it.

On the outer peripheral surface of the flange portion2c, namely on the outer side surfaces thereof in this embodiment, are provided roller portion insertion holes2ehaving rectangular shapes as insertion holes that pass from the exterior space to the receiving recess2d.The roller portion insertion holes2eare provided at two positions or upper and lower positions on each of the outer side surfaces of the flange portion2c. In this embodiment, slide rails2gon which the latch mechanism5is to be supported are also provided on the flange portion2c. The slide rail2gis disposed on the rear surface of the flange portion2c(the surface on the pod body side) or the surface that is opposite to the aforementioned lateral end surface in such a way as to be adjacent to the outer side surface and extend in the direction in which the outer side surface extends. Furthermore, the pod body2has a hold flange2hto be held by a pod transfer robot (not shown) provided on the top thereof and a fixation flange2iprovided on the bottom thereof and to be in actual contact with the support table and to be fixed thereon. The fixation flange2iis provided with an engaged portion etc. (not shown). The hold flange2hand the fixation flange2ihave nothing to do with the characterizing features of the pod according to the present invention, and they will not be described in further detail.

The lid3in this embodiment is a flat plate-like member having a rear surface3ato face the interior space when the opening2aof the pod body2is closed by the lid3and a front surface3bto face the exterior space. On a outer peripheral surface of the flat plate-shaped lid3, namely on the outer side surface in this embodiment, are provided a pair of engaged recesses3cat upper and lower positions corresponding to the positions of the above described roller portion insertion holes2eon the pod body2. The pair of engaged recesses3cinclude concave portions3d. The engaged recess3c, which serves as engaged portion, has an L-shape including a first straight portion3c1that extends in the direction in which the outer side surface of the lid3on which the engaged recess3cis provided extends and a second straight portion3c2that is in communication with the first straight portion and extends in a direction perpendicular to the direction in which the first straight portion extends. One end of the second straight portion3c2opens at the rear surface3aof the lid3. The length and the width of the first straight portion are equal respectively to the length and the width of the above described roller portion insertion holes2eprovided on the pod body2. In the first straight portion3c1, the inner wall3c3located closer to the rear surface3aof the lid3to constitute a part of the engagement recess serves as an engagement surface that engages with a roller portion5bthat will be described later. The front surface3bof the lid3has suction areas to be held by suction by suction pads provided on the door that will be described later. The surface of the suction area has been processed by surface polishing to enable effective suction holding. On the front surface3bof the lid3, there are dust particles or the like that adhered to it when the pod was being transferred in a space in which the degree of cleanness is low. In view of this, in order to provide a seal by the suction pads to prevent diffusion of the dust into the mini-environment, it is preferred that the suction areas be provided to cover nearly the entire area of the front surface3a.

The latch mechanism5has a latch main body5a, roller portions5bserving as engagement portions and link portions5clinking the latch main body5aand the roller portions5b. The latch main body5ais a rectangular column-like member extending in one direction. The latch main body5ais opposed to the rear surface and the side surface of the flange portion2cof the pod body2by a first opposed surface5dof the latch main body5aand a second opposed surface5fof the link portion5c. On the first opposed surface5dis provided a guide groove5gfor receiving the aforementioned slide rail2gin a slidable manner. The guide groove5gextends along the longitudinal direction of the latch main body5aon the first opposed surface5d. The link portions5cproject from the surface on which the first opposed surface is provided in the direction perpendicular to the longitudinal direction of the latch main body5a. There is a pair of such link portions5cdisposed at upper and lower positions corresponding to the aforementioned roller portion insertion holes2e. In this embodiment, the first opposed surface5dand the second opposed surface5fare configured to be opposed to the flange2cwith a small gap being left between them and the flange2cso that any contact or friction will not occur. The gap between the second opposed surfaces5fof the link portions5cand the flange2cmay be provided by including a recess2fin the flange portion2c, as best seen inFIG. 1B.

The roller portions5bprotrude into the lid receiving recess2dthrough the roller portion insertion holes2eprovided on the flange portion2cand abut to portions of the inner walls3c3of the aforementioned engaged recesses3c. The roller portion5bhas a disk-like shape and is rotatably supported on the link portion5cby a rotary shaft5ethat is perpendicular to the bottom surface. The rotary shaft5eextends in a direction perpendicular to both the longitudinal direction of the latch main body5aand the direction in which the link portion5cprojects. By this configuration, the roller portion5bis translated in a plane perpendicular to the rotary shaft5e. In other words, when the latch main body5aslides in the longitudinal direction, the roller portion5brolls about the rotary shaft5ewith its outer circumference (or the outer circumference of the circular disk) being kept in contact with the inner wall while changing the position of contact with the inner wall. In this embodiment, an elastic material such as rubber is attached on the outer circumference of the disk of the roller portion5bso that the disk has elasticity in the circumferential direction. Thus, when the roller portion5bmoves by rotation, the contact portion is prevented from sliding without rotation, whereby generation of dust can be prevented.

In this embodiment, the latch mechanism5is attached to the pod body2by the guide rail2gand the guide groove5g. This eliminates unnecessary contact of the latch mechanism5with the pod body2, whereby generation of dust by such contact can be prevented from occurring. Alternatively, in order to attach the latch mechanism5to the pod body2more steadily to reduce play in sliding, the latch mechanism5may be attached to the pod body2by holding a portion between the inner wall of the rectangular roller insertion hole2eand the guide rail2gby the guide groove5gand a portion of the outer circumference of the disk of the roller portion5b. In this case, the aforementioned addition of the elastic material on the outer circumferential surface of the disk of the roller portion5benables the roller portion5bto abut to both the inner wall of the rectangular roller insertion hole2eand the inner wall3c3of the engagement recess with an appropriate pressing force. Generation of a measure of dust in the contact portions between these members cannot be avoided. Therefore, abrasion resistant materials are used taking into account abrasion characteristics in these contact portions. Alternatively, a roller having a bearing that does not generate much dust may be used, whereby generation of dust due to operation of the latch mechanism5can be controlled.

In the following, a way of fixing the lid3to the pod body2by the latch mechanism5will be described. As shown inFIG. 1A, in the state in which the lid3is received in the receiving recess2dof the pod body2to close the opening2a, each roller portion5bis located at the lower position in the corresponding roller insertion hole2e, i.e. at the closed end portion of the first straight portion3c1of the L-shaped engaged recess3c.The latch mechanism5may be positioned at the closed end portion by the effect of its own weight. In this embodiment, the roller5bis elastic, and the roller portion5bis designed to bias the lid3at this position in such a direction as to bring the lid3into close contact with the pod body2, and the roller portion5bis retained stationary at the aforementioned position by a reaction force of the biasing force. As the latch mechanism5is caused to slide from the above described position upwardly inFIG. 1Ato a latch release position, each roller portion5bmoves to a position at which the first straight portion3c1and the second straight portion3c2of the L-shaped engaged recess3cmeet. With this movement, the roller5bis positioned in the second straight portion3c2that opens on the rear surface3aof the lid, where there is no inner wall3c3to which the roller portion5babuts. Therefore, restraint on the lid3by the roller5bno longer exists, and the lid3is movable in the longitudinal direction of the second straight portion3c2, i.e. in the direction in which the lid3is moved away from the pod opening2a.

In the above described embodiment, there are two latch mechanisms5that are disposed at the rear side edges of the respective flange portions2con both sides. In this embodiment, the latched state is achieved by the weight of the latch mechanisms5themselves. Therefore, there is no need to provide a particular mechanism to retain the latch mechanism5in position when the pod is stored. Thus, the structure of the pod can be made advantageously simple. Such a simple structure is also advantageous in facilitating cleaning for removing dust and in reducing possibility of adhesion of dust to the pod. In actual semiconductor manufacturing factories, semiconductor processing apparatuses arranged side by side are nearly in contact with each other. In the case of the apparatus having the above described structure, the projected area of the semiconductor processing apparatus on the floor on which it is installed does not change particularly even when a latch mechanism drive unit described later is additionally provided. However, the present invention is not limited to the above described mode. The latch mechanisms5may be attached on the upper and lower edges of the flange portion2c. Furthermore, in order to increase the force for securing the lid3to the pod body2, an additional roller(s)5bmay be provided on at least one of the upper and the lower edges. A plurality of roller portions may be provided for one engaged recess3cto increase the aforementioned securing force, and the number of engaged recesses may be decreased. In the above description of the embodiment, the portion that passes through the roller insertion portion2eis only the roller portion5b. However, the rotary shaft5emay also be considered to be a part of the link portion5c, and it is preferred that the portion that passes through the roller insertion portion2ebe the roller portion5bserving as the engagement portion and a part of the link portion5c,and at least the portion that passes through the roller insertion hole2ebe defined as an engagement portion.

In this embodiment, the engaged recess3cis in the form of a L-shaped recessed groove composed of the first straight portion3c1and the second straight portion3c2. More specifically, both the first straight portion3c1and the second straight portion3c2are simple grooves without change in the groove width. However, the first straight portion3C1may have a tapered portion in which the surface to be in contact with the roller portion5bor the inner wall3c3becomes closer to the rear surface of the lid3atoward the closed end. In this case, when, for example, the roller portion5bis at the closed end, the pressing force exerted on the roller portion5bby the inner wall3c3is relaxed and the shape of the contact portion thereof is restored nearly to the circular outer circumference shape of the body, whereby it can generate, in cooperation with the tapered surface, a force that prevents the roller portion5bfrom moving upward. As will be understood from the above, the engaged recess in the present invention is not limited to that in the above described embodiment, as long as it is configured in such a way as to include a non-engagement portion opening on the rear surface of the lid at one end thereof and extending in the thickness direction of the lid and an engagement portion that constitutes the inner wall3c3serving as an engagement surface parallel to the rear surface of the lid.

More specifically, the L-shape in the present invention includes any shape that includes a portion corresponding to the second straight portion that extends in the thickness direction to reach the rear surface and a portion corresponding to the first straight portion that extends in the direction in which the side surface extends (which is perpendicular to the thickness direction). For example, a mode in which a plurality of second straight portions are in communication with one first straight portion, a mode in which a first straight portion that is not in communication with a second straight portion is in communication with another groove at the other end to open on the front side of the lid, and various other modes may be adopted. Such continuous shapes of the groove are considered to be advantageous in facilitating ease of machining and cleaning. Instead of a simple tapered shape, for example, an additional recess may be provided on the surface to be in contact with the roller portion at the closed end in the first straight portion so that the roller portion is to be received in this recess to achieve a locked state. As above, it is preferred that a region including at least one of an undulated surface and an inclined surface be provided for the inner wall3c3to control a biasing force in engagement or a force for retaining the engagement state. By this feature, when the pod is stored, the closed state of the pod opening can be maintained more excellently, that is, more specifically, the closed state can be maintained for a longer time with higher sealing performance.

In this embodiment, elasticity of the circumferential surface of the disk of the roller portion5bserves as means for retaining the latch mechanism5in the latching position. However, the present invention is not limited by this. For example, an elastic member like a spring may be attached to the latch main body5ato always exert a biasing force on the latch mechanism. In this embodiment, the roller portion5bis used as an engaging member and the inner wall3c3of the engaged recess is used as an engaged portion. This greatly reduces the possibility of generation of dust from the engagement portions. However, generation of dust from the rotary roller may matter in some cases. In view of this, a cylindrical contact member having high abrasion resistance may be used instead of the roller member5bin this embodiment. In this case, the contact member may be made of a leaf spring or the like. In this embodiment, the slide rail2gis provided on the rear side of the flange portion2c, because in this configuration diffusion of dust toward the mini-environment is prevented by the flange portion2ceven if dust is generated from the slide rail2g.In this embodiment, the front projected area of the pod does not change, and therefore, no particular problems arise in placing the pod even in the case where it is used in a situation in which semiconductor manufacturing apparatuses arranged side by side are close to each other. However, in order to simplify the structure of the latch mechanism, the slide rail2gmay be provided on the outer side surface of the flange portion2c.

Furthermore, in this embodiment, in achieving the engagement state, the roller portion5bis adapted to make access to the engaged recess3cfrom the outer peripheral surface of the flange portion2c. This mode of access facilitates ease of machining and enables checking of actual engagement state with eyes, allows the slide rail2gand the roller insertion holes2eto be disposed separately from each other, and enables to make the size of the roller5blarge relative to the first straight portion3c1thereby advantageously increasing the engagement force. However, the access may be made, for example, only from the rear side of the flange portion2c. In this case, the engaged recess3cmay be provided in the form of a bore composed of a bore that extends along the thickness direction of the lid3to constitute the second straight portion and another bore that is in communication with and extending from the aforementioned bore toward a different direction to constitute the first straight portion, and it may be provided in the vicinity of the outer periphery of the rear surface3a.

In the above described pod1, the lid3is a flat plate member that is provided with only engaged recesses3con its outer peripheral surface. Therefore, even if it is left in a space in which dust or the like is not controlled, the possibility of adhesion of dust or the like and the possibility of deposition of dust in the interior of the lid is relatively low, because it has no holes for receiving latch keys that are provided in conventional lids. Furthermore, since most part of dust, if any, adhering on the lid will be on the flat front surface thereof, it can be easily removed by cleaning or by presence of downward air flow. In addition, since there is no need to provide conventional operation members for latch keys on the surface of the door, the structure of door can be made simple, and the degree of cleanness of the environment can be enhanced with this simplification.

In the following, a lid opening and closing system for a closed container suitable for use with the above described pod will be described.FIG. 1Ashows the above described pod1, a pod support portion121of the lid opening and closing mechanism101that will be described later, a docking plate123, a door115a, a first opening portion111, a cabinet wall105a, latch mechanism drive units131and a flange cover133. Characteristic features of this lid opening and closing system101include the latch mechanism drive units131serving as means for driving the latch mechanism and the flange cover133. In this embodiment, the latch mechanism drive unit131includes an actuator having a rod that can extend and retract along one axis. The latch mechanism drive unit131is disposed in such a way that when the lid3of the pod1is at the position at which it is held by suction by the door115a, the axes of the latch main bodies5aof the latch mechanisms and the axes of the rods of the corresponding actuators are aligned, and the rods are opposed to each other above and below the latch main bodies5a.

In other words, each latch mechanism drive unit131is composed of the rod that is disposed coaxially with the axis of movement of the corresponding latch main body5aand capable of pushing the latch mechanism5along the axis of movement and an actuator that supports the rod in such a way that the rod can extend and retract along the axis of movement. Thus, the latch mechanism drive unit131in this embodiment is disposed at a position aligned with the corresponding latch mechanism5of the pod1placed at the position at which the lid3is detached so that it can push to drive the latch mechanism5in the vertical direction. It is preferred that the center axis of the rod be aligned with the axis of movement of the latch mechanism5. The upper and lower end faces of the latch main body5aof the latch mechanism5serve as surface to be pressed or the aforementioned contact drive surfaces. Thus, the end of the rod presses this surface to be pressed to drive the latch mechanism5along the axial direction.

Here, the operation sequence of the latch mechanism drive unit131upon actually opening and closing the lid3will be described with reference toFIGS. 6A to 6D.FIGS. 6A to 6Dare perspective views showing only the pod1and the latch mechanism drive unit131.FIG. 6Ashows a state in which the pod1is placed at a position at which the lid3thereof is opened and closed by the door115a. In this state, the surfaces to be pressed of the latch mechanisms5are spaced apart from the rod ends of the corresponding latch mechanism drive units131. The latch mechanism drive units131disposed below start to operate from this state and extend their rods to press the lower end surfaces of the latch main bodies5ato move the latch mechanisms5upwardly as shown inFIG. 6B. By this operation, each roller portion5bis positioned in the second straight portion3c2in the engaged recess3c. In this position, engagement of the roller5band the engaged recess3chas been released, and the lid3can be detached from the pod body2. As described before, the roller portion5bhas an elastic material provided on the outer circumference of its disk, and the roller portion5bis always in contact with the inner wall of the engaged recess3cwith a biasing force generated by its elasticity.

After the above described state is achieved, the lid3is held by suction by the door (not shown inFIG. 6C) and the lid3is detached from the pod body2as the door moves. Thereafter, wafers stored in the interior of the pod body2are taken out through the opening2aof the pod body2thus opened, and wafers having been processed by the processing apparatus are brought into the interior of the pod body2. After transfer of all the wafers has been completed, the lid3is moved by the door back to the position shown inFIG. 6C, and then operation for closing the opening2awith the lid3is performed. Thereafter, as shown inFIG. 6D, the latch mechanism drive units131disposed below the pod1retract the rods, and the latch mechanism drive unit131disposed above the pod1start their operation to extend the rods, thereby pressing the upper end faces of the latch main bodies5a, whereby the latch mechanisms5are moved downwardly. Thus, each roller portion5bis located in the first straight portion3c1in the engaged recess3c. In this position, engagement of the roller portion5band the inner wall3c3is established, and the lid3is fixed to the pod2. After the engagement is achieved, the latch mechanism drive units131disposed above the pod1retract the rods. Thus, the state of the system returns to that shown inFIG. 6A. By the above described operations of the latch mechanism drive units131, a sequence from detaching to attaching of the lid3from/to the pod1is performed.

The lid opening and closing system according to the embodiment of the present invention is further provided with a flange cover133. The flange cover133is an annular structure having an inner peripheral surface that can be opposed to the entire outer peripheral surface of the flange portion2cof the pod2. The flange cover133is provided in such a way as to project perpendicularly from the cabinet wall105aon the side on which the pod1is placed (i.e. on the exterior space side). In the state in which the pod1is placed at a position at which the lid3is opened and closed by the door115a, the flange cover133covers the outer peripheral surface of the flange portion2cof the pod2to block passages that directly lead from the exterior space to the outer peripheral surface. In this embodiment, there are passages leading from the exterior space to the storage space2din the pod body2through the roller portion insertion holes2ewhether the latch mechanism5is at a position at which it engages the lid3or a position at which it does not engage the lid3. The interior of the pod is typically kept at a positive pressure in relation to the exterior space that is in communication therewith thanks to the effect of clean air supplied to the mini-environment. Therefore, in conventional systems, outward air flow is present in the roller portion insertion holes2e, and there are no problems in dust control. In this embodiment, the flange cover133is further provided, whereby passages leading from the storage space2dto the exterior space formed substantially through the roller portion insertion holes2ecan be made as small as possible. By this feature, it is possible to prevent very small dust particles from entering the storage space2dthrough the roller insertion holes2eby, for example, expansion of the region of molecular motion.

In the above described embodiment, two actuators or latch mechanism drive units131are disposed respectively above and below each latch mechanism5. By this arrangement, the structure of the latch mechanism5can be made simple, and the possibility of entrance of dust is advantageously reduced. However, the advantages of the present invention associated with disposition of the latch mechanism5can be achieved also by additionally providing biasing means for biasing the latch mechanism5in the axial direction and disposing a latch mechanism drive unit131either above or below the latch mechanism5. Furthermore, for example, a latch mechanism drive unit131may be constructed by providing a cam surface in the form of an inclined surface or slope that rises or falls relative to the docking plate123in a direction along the direction of movement of the docking plate123and cam means that is in contact with the cam surface to follow it so that a rod or the like moves upward or downward with operation of the cam means. In other words, a kind of cam mechanism may be provided between the pod support table (or a container support table) and the latch mechanism drive unit, and the latch mechanism drive unit may be driven by the cam mechanism. By this feature, a drive source for driving actuators or the like can be eliminated.

In this embodiment, the flange portion2cis fully covered with the flange cover133, whereby direct communication between the storage space2dand the exterior space through the roller portion insertion holes2eis prevented. This configuration is advantageous, for example, in facilitating ease of cleaning of the roller insertion holes2eand the roller portions5b. Alternatively, for example, the thickness of the link portion5cmay be made so small that the roller portion5band the link portion5ccan be received in the roller portion insertion hole2e,and the receiving portion may be covered with a cover. In this case, advantages of the present invention can be achieved without providing an additional member on the lid opening and closing system.

In the above described mode, the closed container according to the present invention can be used only by adding the latch mechanism drive units131and the flange cover133to a conventional lid opening and closing system. This additional features does not cause a particular change in the actual projected area of the semiconductor processing apparatus on the floor on which it is installed. Therefore, it is easy to modify an existing semiconductor manufacture line to enable use of the closed container according to the present invention. With the above described configuration of the lid opening and closing system, the closed container according to the present invention can be used, and the above described various advantages provided by the closed container can be enjoyed. Although it is preferred that the flange cover133be provided, it may be difficult to provide it in some cases due to, for example, a specific structure of the docking plate123. In such cases, if the semiconductor manufacturing process is compliant with conventional design rules, the flow rate of clean air supplied from the mini-environment into the pod may be increased to prevent entrance of dust particles having sizes that will matter.

Next, the lid opening and closing system adapted to the closed container according to the present invention will be described.FIG. 7is a cross sectional side view showing the general structure of the system.FIG. 8is an enlarged view showing a pod support portion, a door, a pod and a lid etc. in the system101in a similar manner.FIG. 9schematically shows the pod support portion and the door etc. in the state in which the opening of the pod is closed by the lid. The lid opening and closing system101has a cabinet105that defines a mini-environment103and a pod support portion121provided adjacent to the cabinet105. The cabinet105is provided with a fan107, a robot109, a first opening111, a second opening113and a door system115. The fan107is provided on the cabinet105in the upper portion of the mini-environment103to introduce the air in the space outside the cabinet105into the mini-environment. The fan107is equipped with a filter suitable for the degree of cleanness in the exterior space to remove contaminant such as dust from the air introduced from the exterior space. The bottom portion of the cabinet105has a structure that allows the air to flow to the exterior. Thus, dust particles or the like generated in the mini-environment103are brought by the air flow and discharged to the exterior space from the bottom of the cabinet105.

A robot arm109aof the robot109can extend to the exterior of the mini-environment trough the first opening111and the second opening113. The first opening111is closed, in a way, by the door115aof the door system115, where a gap is left between the outer periphery of the door115aand the inner peripheral surface of the first opening111. Thus, it should be said that the door115acan nearly close the first opening111. The second opening113leads to the interior of a wafer processing apparatus117. The details of the wager processing apparatus117will not be described in this specification, since they have no direct bearing on the present invention. The latch mechanism drive unit131and the flange cover133have been already described, and no further description will be made. In addition, to facilitate understanding, the flange cover133is not illustrated inFIGS. 7 to 9.

The pod support portion121has a docking plate123, a pod fixing system125and a docking plate drive system127. The upper surface of the docking plate123is substantially flat, and some portions of the pod fixing system125is provided thereon. The pod1according to the present invention is placed on the upper surface of the docking plate123, and the aforementioned portions (specifically, in the form of pins) of the pod fixing system125come into engagement with engaged portions (not shown) provided on the bottom surface of the pod1to fix the pod1at a prescribed position on the docking plate123. The docking plate123is configured in such a way that the opening2aof the body of the pod1is just opposed to the above described first opening111when the pod1is placed on the upper surface of the docking plate123. The docking plate drive system127drives the docking plate123and the pod1fixed at the prescribed position thereon toward/away from the first opening111using a guide rail127aand a drive cylinder127b.

One end of the drive cylinder127bis fixed to the body121aof the support table, and the other end or the end of an extendable/retractable cylinder is fixed to the docking plate123. The docking plate123is supported on the guide rail127ain a slidable manner so that it can slide on the guide rail127awith extension/retraction of the cylinder end of the drive cylinder127b. The docking plate123is located farthest from the mini-environment103when it is at a position that allows placement of the pod1onto it from the exterior (loading) or removal of the pod1from it (unloading), and closest to the mini-environment103when it is at a position that allows detachment of the lid3of the pod1.

On the surface of the door115aare provided suction pads115k. The suction pads115kare supplied with a negative pressure from a negative pressure source108(seeFIG. 10) through pipes (not shown) when they are in contact with the lid3, whereby the lid3is sucked by the suction pads115a. Thus, the lid3can be held by the door115a. The door system115includes a door arm115b, a door opening and closing actuator115cand a door elevator mechanism115d. The door arm115bis a rod-like member. The door arm115bsupports the door115aat one end and is connected to the door opening and closing actuator115cat the other end. The door arm115bis pivotally supported by a pivot shaft at an appropriate intermediate position so as to be able to swing about that position. The door arm115bis swung about the rotation center axis by the door opening and closing actuator115c, whereby the end of the door arm115band the door115asupported thereon are moved toward or away from the first opening111. The door elevator mechanism115dsupports the door opening and closing actuator115c and the pivot shaft of the door arm115band has a vertical movement actuator to move the actuator, the door arm115band the door115aalong the vertical direction along a guide extending in the vertical direction.

As shown inFIG. 9, a substantially annular seal member115mis provided in the periphery of the surface of the door115athat is opposed to the lid3so that the seal member115mcooperates with a seal surface provided on the front surface3bof the lid3. In the state in which the lid3is held by suction by the suction pads115kprovided on the surface of the door115a, the seal member115mis in close contact with the seal surface3c. Small dust particles or the like adhering on the front surface of the lid3are confined in a sealed space thus formed, whereby diffusion of dust particles to the environment is prevented. In this embodiment, the lid3is held only by the suction pads115k. However, an evacuation port for suction may further be provided on the front surface of the door to evacuate the space that is defined by the door115a, the lid3and the seal member115mand sealed by the seal member115m. In this case, small dust particles or the like can be removed positively, and the lid3can be held more firmly by the door115a.Alternatively, the suction pads115kmay be eliminated, and the seal member115mmay be used as a kind of suction pad.

FIG. 10is a block diagram showing the configuration of this FIMS system101. The above described fan107, robot109, door system115, pod fixing system125and docking plate drive system127are controlled by a control apparatus102having a timer102a. The door closing and opening actuator115cand the door elevator mechanism115din the door system115may be controlled independently from each other. However, in the actual operation, they are controlled in such a way that they operate according to a sequence time chart. The latch mechanism drive unit131is also controlled by the control apparatus102so as to operate in synchronization with the aforementioned operation sequence of the door system115. Supply of negative pressure to the suction pads115kfrom the negative pressure source108and shutting-off thereof (breaking of the negative pressure) are controlled by the control apparatus102.

The docking plate drive system127turns on and off the driving by the drive cylinder127b. It is necessary to detect, with reliability, two predetermined position of the docking plate123driven by the operation of the drive cylinder127, namely the load position that allows placement of the pod1and the dock position that allows transfer of wafers from/into the pod1. For this purpose, to the docking plate drive system127is connected a load sensor127dthat detects placement of the pod1on the docking plate123and presence of the docking plate123at the position allowing loading and unloading the docking plate123with the pod1. In addition, to the docking plate drive system127is also connected a dock sensor127cthat detects whether or not the docking plate123is present at the above described dock position. In the present invention, since the lid3has high stiffness and is hard to deform, and switching between engagement and disengagement of the latch mechanism5is achieved by operation along only one axis, the possibility of failure of engagement of the latch mechanism5is much lower than that in conventional structures. In view of this, in this embodiment, an on/off signal indicative of the extended/retracted state of the rod is generated and supplied to the latch mechanism drive unit131, and engagement and disengagement of the lid3and the pod body2are detected by this on/off signal. The present invention is not limited by this mode of detection. The engaged/disengaged state may be detected by directly sensing the operation of the latch mechanism5using, for example, an optical sensor.

In the following, the operation of the lid opening and closing system101in actual wafer processing operations will be described. In wafer processing operations, a pod1containing a predetermined number of wafers and filled with clean air is placed on the docking plate123. When the pod1is placed on the docking plate123, the pod fixing system125operates to achieve the prescribed position of the pod1on the docking plate123. Thereafter, the docking plate drive system127operates to move the pod1toward the first opening111. Specifically, the pod1that has been made integral with the docking plate123by the pod fixing system125is moved by driving the docking plate123by the drive cylinder127b. During this operation, the door115ais kept stationary at the position at which it substantially closes the first opening111. The driving operation is completed when the lid3of the pod1abuts the abutment surface of the door115a, and a prescribed positional relationship between the docking plate123and the first opening portion111is achieved. At this time, the latch mechanism drive units131and the latch mechanisms5are in the prescribed positional relationship as shown inFIG. 6Aand other drawings. In this state, the latch mechanisms drive unit131start to operate, and engagement of the pod body2and the lid3is released. Simultaneously, the suction pads115ksuck the lid3, whereby the lid3is held by the door115a. In addition, the space formed between the front surface of the lid3and the surface of the door115ais brought into a sealed state by the seal member115m.

In this state, the door opening and closing actuator115cstarts to operate. Thus, the door arm115bswings to move the door115athat is holding the lid3from the first opening111to the interior of the mini-environment103. When the door arm115bstops at a prescribed swing angle, the door elevator mechanism115dstarts to operate, whereby the door115ais moved downward with the door opening and closing actuator115c. By this operation, the first opening111is fully opened, and the mini-environment103is in communication with the interior of the pod body2via the first opening111. In this state, the robot109starts to operate, and transfers wafers4from the interior of the pod1to the wafer processing apparatus117through the second opening113, using the robot arm109a. Furthermore, while this state is maintained, the robot109also transfers wafers that have undergone a certain processing in the interior of the wafer processing apparatus117into the interior of the pod1. By reversing the above procedure basically, the lid3is attached to the pod, and the pod1can be detached from the lid opening and closing system101.

By using the above described pod and the FIMS system in the form of a lid opening and closing system suitable for the pod, influences of very small dust particles adhering on the surface of the lid that closes the pod opening can be reduced, and generation of dust upon operation of opening and closing the lid and diffusion of dust thus generated into the mini-environment and the pod can also be reduced. More specifically, fixation of the lid3to the pod body2and releasing of the fixation are performed from the outer lateral sides of the flange portion2cprovided on the pod body. For example, air flow directed from the vicinity of the outer periphery of the first opening111to the exterior space may be generated, which can further reduce the possibility of diffusion of small dust particles or the like into the pod or the mini-environment, which has already been reduced by their arrangement.

The above description of the embodiment has been directed mainly to an FIMS system for wafers. However, the applications of the invention are not limited to that system, but the present invention can also be applied to closed containers for storing display panels, optical disks or the like.