WO2010137556A1

WO2010137556A1 - Atmosphere replacement device

Info

Publication number: WO2010137556A1
Application number: PCT/JP2010/058745
Authority: WO
Inventors: 勝則坂田; 英和奥津
Original assignee: ローツェ株式会社
Priority date: 2009-05-27
Filing date: 2010-05-24
Publication date: 2010-12-02
Also published as: TW201110259A; KR101668823B1; CN102449752A; KR20120027010A; JPWO2010137556A1; CN102449752B; JP5448000B2; TWI500104B

Abstract

An improved atmosphere replacement device configured to purge a FOUP type container by means of a purge gas. An atmosphere replacement device is provided with a non-nozzle type purge plate designed in such a manner that a laminar purge gas flow flows out of an outflow surface. The purge plate can be moved between a standby position and an operation position by a purge plate drive mechanism. During purging, the purge plate is placed at the operation position and, while facing the open surface, purges a FOUP type container by causing the laminar purge gas to flow out of the purge plate into the inside of the open surface of the FOUP type container.

Description

Atmosphere replacement device

The present invention provides an atmosphere that is isolated from the outside during processing between thin plate substrates such as semiconductor wafers, liquid crystal display panels, organic EL display panels, plasma display panels, and solar cell panels. The present invention relates to an atmosphere replacement device and an atmosphere replacement method for replacing an atmosphere inside a container with an atmosphere of an inert gas or the like with respect to a sealed container that stores thin plate substrates at a predetermined interval.

Conventionally, in a processing apparatus that performs various processes such as film formation and etching on a thin substrate such as a semiconductor wafer, an EFEM (Equipment Front End Module) that performs transfer, and a sorter that reads and sorts lot numbers, In order to prevent particles floating inside from adhering to the thin plate substrate, a highly purified micro space called a mini-environment system that keeps the internal atmosphere of the device exposed to the thin plate substrate highly clean Therefore, a device for maintaining high cleanliness at a relatively low cost has been made.

However, in recent years, the design rule of the semiconductor circuit line width has been miniaturized and the wafer diameter has been increased, and problems that cannot be solved only by high cleaning by the conventional mini-environment method have appeared. The surface of the thin plate substrate processed by the processing equipment and brought into the sealed container reacts with oxygen and moisture in the air, and a film that is undesirable in various processing steps such as a natural oxide film is generated. In addition to oxygen and moisture, the contaminants used in the processing equipment are brought into the sealed container while still attached to the thin plate substrate, and these contaminants reach other thin plate substrates in the sealed container. May contaminate and adversely affect the next processing step, leading to a decrease in yield.

As a method for solving such problems, the air and contaminants that have entered the sealed container are removed with an inert gas, and the inside of the sealed container is filled with the inert gas to oxidize the surface of the thin plate substrate contained inside. Various methods for preventing this have been considered.
In [Patent Document 1], a gas supply nozzle that is provided at a predetermined distance from a wafer placed on a FOUP (Front Opening Unified Pod) that is one of hermetically sealed containers and blows an inert purge gas in a vertical direction. A method of removing contaminants attached to the wafer surface by moving up and down is disclosed. However, in this method, it is possible to blow away contaminants attached to the surface of the wafer, which is a kind of thin plate substrate, from the wafer, but the blown contaminants are discharged into the mini-environment space. There is a possibility that inconvenience may occur such that dust adhered to the inside of the FOUP or the wafer surface is scattered in the FOUP to damage the wafer processing surface.

In [Patent Document 2], in addition to the nozzle for supplying the inert gas, an auxiliary nozzle for sucking the inert gas flowing along the inner periphery of the FOUP is provided, and the inert gas draws a circular trajectory in the FOUP. It creates a flow path that can do this. In addition, a method is disclosed in which purge is performed efficiently by providing a cover so as to cover the FOUP opening surface and the nozzle, thereby suppressing the outflow of purge gas to the outside.

However, even with this method, the purge gas flowing out from the nozzle becomes a turbulent flow, and the inconvenience of damaging the wafer processing surface by scattering dust adhering to the wafer surface into the FOUP is sufficiently eliminated. Absent. In addition, when the gas is blown from one vertical end of the container opening and discharged to the other vertical side, the inert gas swirls and mixes with air in the container, so that the replacement is slowed and required as a result. The amount of inert gas was increased, which was insufficient for efficient purge. In addition, there is a problem that the cost increases due to an increase in the number of components to be added, such as adding a sealed space forming portion or providing a nozzle for flowing purge gas in addition to a nozzle for flowing purge gas.

JP 2005-33118 A International Publication WO2005 / 124853

The present invention has been made in view of the above problems, and provides an atmosphere replacement device that can efficiently and effectively replace the internal atmosphere of a FOUP type container with a purge gas without using a nozzle. The main purpose is to provide.

According to one aspect of the present invention, an atmosphere replacement device for purging a FOUP type container with a purge gas is provided. Here, the FOUP type container is a storage container having an open surface on the front surface and the open surface can be sealed with a cover, and includes, for example, FOUP (Front Opening Unified Pod) used between semiconductor processes. Not. In contrast to the conventional nozzle-type purge gas ejection mechanism, this atmosphere replacement device uses a non-nozzle-type purge plate designed to flow a laminar purge gas from the outflow surface. This novel purge gas ejection mechanism (non-nozzle purge plate) has a standby position and an operating position. The purge plate can be moved between a standby position and an operating position by a purge plate driving mechanism (for example, an elevating mechanism). During the purge period, the purge plate is placed in this operating position, and in a posture facing the open surface of the FOUP type container, laminar purge gas flows out toward the inside of the open surface (preferably the center of the open surface). And operate to purge the vessel.

The purge plate is a key component of the present invention. Compared with the conventional nozzle type, this new purge gas ejection mechanism is (a) a uniform laminar flow in which the gas flow has a relatively large gas cross-sectional area (in terms of total pore area) by the plain outflow method. ) Because the gas flow is relatively slow (preferably in the range from 0.05 meter / second to 0.5 meter / second at a position 20 mm forward from the purge plate), in conventional nozzle type purge gas ejection mechanisms The "stirring phenomenon (with the phenomenon that residual air and supply gas are mixed in the FOUP type container)" that was encountered can be sufficiently suppressed, and as a result, effective and efficient gas replacement is possible. Become.

Despite the slow gas flow exiting the purge plate, it has the potential to perform purging in less time than the high speed gas flow obtained from conventional nozzle types. This is an unexpected effect. The gas flow exiting the purge plate is a slow laminar flow. Accordingly, the “dust generation phenomenon (a phenomenon in which dust rises in the FOUP type container)” encountered in the conventional nozzle type purge gas ejection mechanism can be sufficiently suppressed by this slow gas laminar flow. In a semiconductor manufacturing factory (FAB), dust (particles) contaminates semiconductor wafers and the like, resulting in a significant decrease in yield, and this dust generation suppression function based on the purge plate is very important.

The operation position of the purge plate will be described. In a preferred form, the operating position of the purge plate is located on the movement path of the FOUP type container. Therefore, when the purge plate is in the standby position, the FOUP type container can occupy the operating position of the purge plate. In this occupied state, the front surface of the FOUP type container may abut against the door. Note that, like the door of the conventional load port, the door is configured such that the manipulator of the transfer robot can pass when the door is open. In this abutting state, the door is removed from the FOUP type container (open the container) and attached to the door itself by the same mechanism as that of a conventional load port door, or vice versa. It is attached to the open surface of the removed FOUP type container (sealing the container). When the purge plate is in the operating position, the FOUP type container is in a position (purge gas receiving posture) where the open surface faces the purge plate and directly receives the purge gas flow from the purge plate. For this reason, the FOUP type container moves from the “occupied position” to the “purge gas receiving position” prior to purging. Thereby, the working space of the purge plate is secured.

The work space securing mechanism may be a FOUP type container moving mechanism that moves the FOUP type container along the movement path. This can be realized by, for example, a stage moving mechanism that moves a stage on which a FOUP type container is placed like a conventional load port. Alternatively or in combination, a door movement mechanism can be provided that moves the door away from the FOUP type container. By such a working space securing mechanism, the operation position of the purge plate is located between the FOUP type container (the open surface thereof) and the door.

In a preferred embodiment, the purge plate includes an ejection suppression element that suppresses or inhibits the ejection output of the purge gas. Preferably, the ejection suppressing element is made of a porous material such as an air filter material.

In a preferred form, the atmosphere replacement device is designed to be compatible with the load port.

The door of the atmosphere replacement device itself may be realized by a normal load port door. In a preferred embodiment, the atmosphere replacement device is provided with a door moving mechanism that moves the door in the X direction (for example, the horizontal direction) and the Y direction (for example, the direction orthogonal to the X direction, for example, the vertical direction).

In certain applications, the atmosphere replacement device is placed adjacent to the mini-environment space unit, as is a normal load port. That is, there is a mini-environment space beyond the door, and when the door is opened, the transfer robot accesses the FOUP-type container from the mini-environment space side using a manipulator (robot arm) (to perform wafer transfer work). . In this type of application, the atmosphere replacement device performs purging (atmosphere replacement) with the FOUP type container set in the opening (only the head of the FOUP type container including the open surface enters the opening). To do. The opening is defined by the inner wall of the atmosphere replacement device. Therefore, in general, there is a gap between the inner wall of the atmosphere replacement device and the door, and the inside of the opening is in limited communication with the high cleanliness air from the mini-environment space unit through this gap.

Therefore, in the state where the FOUP type container is set in the opening, the atmosphere replacement device is always exposed to the high cleanliness air through the gap in the opening. In general, the mini-environment space unit is placed under a higher atmospheric pressure (“positive pressure”) than the outside in order to avoid the entry of low clean air from the outside.

Another feature of the present invention relates to an improvement in the case where the atmosphere replacement device with a purge plate of the present invention is applied to the gap communication type atmosphere replacement device (purge port) as described above. Therefore, these features can also be applied "in principle" to nozzle-type atmosphere replacement devices. However, even if these features are incorporated into a nozzle-type atmosphere replacement device that cannot suppress the “stirring phenomenon” and “dust generation phenomenon” inherent to the nozzle-type purge gas ejection mechanism to an acceptable level, the basic performance is improved. Cannot be expected, so synergistic effects are not expected. In other words, it is effective when applied to an atmosphere replacement device having basic performance that suppresses the “stirring phenomenon” and “dust generation phenomenon” to an acceptable level.

In a preferred embodiment, a mechanism for effectively eliminating the gap is provided in the atmosphere replacement device. Specifically, an inner wall shield cover having a labyrinth structure is provided on the inner wall of the atmosphere replacement device. Furthermore, a door shield cover having a similar labyrinth structure is also provided on the door. And it arrange | positions and comprises so that the said clearance gap may be non-contact sealed by the said inner wall shield cover and the said door shield cover. This effectively eliminates the gap, so that the entry of high cleanliness air is reduced as much as possible. As a result, the time (purge time) required for the required purging can be shortened. Furthermore, because of the characteristics of the labyrinth seal structure, contact or collision between the inner wall and the door (here, contact or collision between the inner wall shield cover and the door shield cover) does not occur. Is effectively prevented.

In another preferred embodiment, a gap adjusting mechanism that makes the gap variable is provided in the atmosphere replacement device. Specifically, an inner wall shield cover having a labyrinth structure is provided on the inner wall of the atmosphere replacement device. Similarly, a door shield cover having a labyrinth structure is also provided on the door. Furthermore, a door drive mechanism for moving the door in the horizontal direction is provided. And it is designed so that the degree of the seal between the inner wall shield cover and the door shield cover can be adjusted (and therefore the gap can be adjusted) depending on the horizontal position of the door. Accordingly, the gap can be effectively adjusted to a desired size (an effective size corresponding to the “depth” of the shield), so that the purging time can be shortened. Moreover, the penetration of the high cleanliness air into the opening can be appropriately adjusted.

In the case where an atmosphere replacement device with a purge plate is placed next to the mini-environment space, the flow of high cleanliness air communicating through a gap (see the high cleanliness air passage 121 in FIG. 9) The inventor of the present application has found that, in the period during which the flow is supplied to the FOUP-type container FOUP-type container (purge period), the purging time is shortened as a result of being appropriately present (see the flow schematic diagram in FIG. 9). ). When the operation of the purge plate is stopped (the purge operation of the purge plate is completed), the purge gas stream disappears, so the purge gas curtain effect disappears, and the high cleanliness air enters under this mode (purge plate operation completion mode) ( Some will penetrate into the back of the FOUP type container), resulting in prolonged purge time.

In order to eliminate this delay factor, it is conceivable that the FOUP type container is covered with a cover immediately after the operation of the purge plate is completed (for example, on the order of milliseconds, for example, about 100 milliseconds). However, it is necessary to put the cover on a place other than the door in a standby state, which is not practical. In reality, when the purge plate no longer becomes an obstacle to the movement of the FOUP type container (for example, when the purge plate moves back to the standby position), the FOUP type container is moved to the door, the cover is removed from the door, and the FOUP type is removed. It will be attached to the container. The time from the completion of the purge plate operation to the sealing of the FOUP type container by this method can be realized in a relatively short time (for example, about one second).

Alternatively or in combination, a mechanism can be provided that effectively reduces the ingress of high clean air from the mini-environment unit under purge plate operation completion mode. Thereby, the required purging time can be further shortened.

In one configuration example, this mechanism is realized by being provided on the inner wall of the auxiliary nozzle that supplies the purge gas toward the FOUP type container. Preferably, the auxiliary nozzle is controlled to operate during the purge plate operation completion mode. Although this is a simple configuration, it has been found that it is sufficiently effective as a result (especially effective in terms of reducing the required purging time).

The depth-adjustable labyrinth mechanism (variable gap adjusting mechanism) can also be used for this purpose. Specifically, when the purge plate operation is completed (or starting from an appropriate timing preceding the completion point), the horizontal door drive mechanism moves the door toward the deepest seal position in the horizontal direction to operate the purge plate. During the stop, the door is controlled to be maintained at the deepest sealing position.

The depth adjustable labyrinth mechanism (variable gap adjustment mechanism) can control the size of the gap according to the internal / external differential pressure (positive pressure) of the mini-environment space unit used. It is. Thereby, the magnitude of the internal / external differential pressure (positive pressure) of the mini-environment space unit to be used (or the usage environment of the mini-environment space unit) is compensated.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description made with reference to the drawings. The drawings to be referred to are as follows.
It is a perspective view which shows the outline | summary of a general processing apparatus. It is sectional drawing of a processing apparatus. It is a perspective view which shows the structure of FOUP which is one of the wafer storage containers. It is a perspective view which shows the outline | summary of a load port. It is sectional drawing which shows the purge port (atmosphere substitution apparatus) which concerns on one Example of this invention. FIG. 6 is a perspective view showing the periphery of the FIMS door of FIG. It is a perspective view which shows the Example of a purge plate. It is a perspective view which shows another Example of a purge plate. FIG. 5 is a cross-sectional view schematically showing an air flow in the FOUP in order to explain how the FOUP is purged by the purge port based on the embodiment of the present invention. It is a perspective view of the door drive mechanism which drives a FIMS door horizontally based on the example of the present invention. It is sectional drawing which shows the operation | movement sequence of a purge port. It is a figure which shows the piping in a purge plate, and the system of signal input / output. It is a perspective view which shows the FIMS door drive mechanism periphery. It is the perspective view which showed

shield cover

67a, 67b attached to the FIMS door based on the Example of this invention. It is explanatory drawing which showed test environment. It is the graph which showed transition of the oxygen concentration by the difference in nitrogen gas (purge gas) flow volume and supply time when the internal / external pressure difference of the test mini-environment space unit is 3.5 Pa and 2.5 Pa. It is the graph which showed the relationship between the internal / external differential pressure when oxygen gas flow volume and supply time were made constant, and transition of oxygen concentration. It is the graph which showed transition of the oxygen concentration by the difference in nitrogen gas flow volume and supply time when internal / external differential pressure is made constant.

In the following, the invention will be described in detail with reference to specific embodiments shown in the drawings. FIG. 1 is a perspective view of the processing apparatus 1, and FIG. 2 is a sectional view thereof. The processing apparatus 1 is installed in a factory called a clean room, which is managed in a relatively clean atmosphere of class 100 with 0.5 μm dust. The processing apparatus 1 mainly includes a load port 2, a mini-environment space unit 3, a transfer robot 4, a fan filter unit 5, a vacuum chamber 6, and a process chamber 7. The mini-environment space unit 3 has a frame, a wall surface that is fixed to the frame and is separated from the external atmosphere, and cleans the air from the outside into highly purified air, and then flows into the mini-environment space unit 3 as a downflow. A fan filter unit 5 which is a high clean air introducing means to be introduced is provided. The fan filter unit 5 is installed on the ceiling of the mini-environment space unit 3 and sends the air downward toward the inside of the mini-environment space unit 3, and the dust and organic matter present in the sent air. The filter 9 which removes contaminants, such as these, is provided.

Further, the floor surface 10 (FIG. 2) of the mini-environment space unit 3 is made of a member capable of air circulation having a predetermined opening efficiency such as a punching plate. With these configurations, the clean air supplied to the inside by the fan filter unit 5 always flows downward in the mini-environment space unit 3 and is discharged from the floor surface 10 to the outside of the apparatus. The mini-environment space unit The inside of 3 is kept in a highly clean atmosphere. The transfer robot 4 transfers a wafer 15 (FIG. 3A), which is a kind of thin plate, between the container 13 called FOUP and the process chamber 7, and the arm movable part of the robot 4 is a magnetic fluid. By adopting a seal structure for preventing dust generation such as a seal, a contrivance has been made to minimize the adverse effect of dust generation on the wafer 15. With this configuration, the wafer 15 is transferred by the transfer robot 4 in a highly clean atmosphere. Further, the internal pressure of the mini-environment space unit 3 is a pressure “positive pressure” higher than the outside, and is typically maintained to have a differential pressure of about 1.5 Pa. In this way, by preventing the entry of contaminants and dust from the outside, the cleanliness inside the mini-environment space unit 3 can be maintained at a high cleanliness of class 1 or higher with 0.5 μm dust. It has become.

Next, the load port 2 will be described below with reference to FIGS. The load port 2 is fixed at a predetermined position of a frame 3a forming the mini-environment space unit 3, and supports a stage 14 on which a FOUP 13 which is a kind of a sealable container is placed at a predetermined position, and the stage 14 The stage drive mechanism 29 for moving the stage 14 forward and backward, the port opening 11 for the transfer robot 4 to unload and load the wafer 15 in the FOUP 13, and the port opening 11 with a certain gap therebetween. There is a FIMS door 12 integrated with a cover 17 for sealing the inside of the FOUP 13 at a closing position, and a FIMS door raising mechanism 19 for moving the FIMS door 12 up and down.

For opening and closing operations of the FIMS door 12, cover opening / closing means for reciprocating the FIMS door 12 integrated with the cover 17 to a position separated from the FOUP 13 is provided, or the stage driving mechanism 29 causes the FOUP 13 to move. This can be achieved by reciprocating the placed stage 14 to a position separated from the FIMS door 12 integrated with the cover 17. In this case, the stage drive mechanism 29 also serves as a cover opening / closing means. These mechanisms correspond to a FIMS (Front-opening Interface Mechanical Standard) system defined by the SEMI standard, which is a standard related to semiconductor manufacturing.

The stage drive mechanism 29 includes a motor 29a as a drive source and a feed screw 29b. The rotation of the motor 29a is transmitted to the feed screw 29b, and the stage 14 fixed to the feed screw 29b can be moved to an arbitrary position. It is possible. In place of the motor 29a and the feed screw 29b, a cylinder using fluid pressure such as air pressure or hydraulic pressure may be used. The FOUP 13 is accurately placed at a predetermined location on the stage 14 by a kinematic pin 30 as positioning means 30 disposed on the stage 14 and is engaged with the stage 14 by an engaging means (not shown). .

The FIMS door 12 is fitted to a registration pin 23a for performing integration by positioning and suction force with respect to the cover 17 of the FOUP 13, and a latch key hole 24 provided in the cover 17, and is rotated to latch the key hole. 24, and a latch key 23b that engages with the latch key hole 24 and switches between a locked state and an unlocked state. With these configurations, the cover 17 and the carrier 16 constituting the FOUP 13 are unlocked, and the cover 17 and the FIMS door 12 are integrated.

The FIMS door 12 is attached to the FIMS door lifting mechanism 19 via a bracket 31 so as to be movable up and down. With these configurations, the FIMS door 12 raised to a position where it can be integrated with the cover 17 of the FOUP 13 is integrated with the cover 17 as described above. For lowering, the FIMS door 12 can be lowered to an arbitrary position after releasing the lock mechanism 25 provided in the cover 17. In FIG. 4, the FIMS door lifting mechanism 19 can move the FIMS door 12 up and down to an arbitrary position by causing the motor 19a as a driving source to rotate the feed screw 19b in the normal direction or the reverse direction. However, instead of this, a cylinder using fluid pressure such as air pressure or hydraulic pressure may be used.

In addition to the above-described configuration, the load port 2 includes a mapping sensor 32 that detects which shelf 18 in the FOUP 13 has the wafer 15 mounted thereon or the number thereof.

In FIG. 4, the mapping sensor 32 uses a pair of transmission sensors having an optical axis parallel to the surface on which the wafer 15 is placed, and is spaced so as to surround the peripheral edge of the wafer 15 on the horizontal plane. It is mounted on a sensor mounting portion 33 having a substantially U shape. Both ends of the sensor attachment portion 33 are rotatably attached to the sensor drive mechanism 34. The drive source of the sensor drive mechanism 34 is a motor or a rotary actuator. When these drive sources rotate, the sensor mounting portion 33 rotates around the axis of the drive source, and the mapping sensor is attached to the upper part. 32 enters the inside of the carrier 16.

The sensor driving mechanism 34 is fixed to the bracket 31 and can be moved up and down in conjunction with the operation of the FIMS door lifting mechanism 19, thereby detecting the presence or absence of the wafer 15 in all the shelves 18 in the carrier 16. It becomes possible to do. Further, output signals to the respective drive mechanisms and input signals from sensors and the like are controlled by the control unit 37.

In addition to the above configuration, a wall surface 35 is provided in order to prevent dust generated from each drive source and movable part provided inside the load port 2 and dust from the outside from entering the mini-environment space unit 3. In order to prevent the entry of low clean air from the outside, the portion facing the outside can be covered with the cover 36. It is also possible to provide an exhaust fan 37 for discharging dust generated in the load port 2 to the outside. This not only prevents the dust from flowing into the mini-environment space unit 3, but also the downflow of highly purified air flowing through the mini-environment space unit 3 enters from the upper opening of the wall surface 35. Then, it passes through the opening provided in the bottom surface of the load port 2 and is discharged to the outside of the apparatus, and contaminants such as dust adhere to the cover 17 in the lowered position in an integrated state with the FIMS door 12. Can also be prevented.

Next, FOUP 13, which is a kind of container that can be sealed, will be described. The FOUP 13 is a sealable container for isolating the wafer 15 that is an object to be stored from a low-clean external atmosphere by maintaining the inside in a high-clean atmosphere, and carrying between the processes. FIG. 3 is a perspective view showing the structure of a FOUP 13 which is a kind of semiconductor wafer storage container. The FOUP 13 seals the inside of the carrier 16 by sealing the carrier 16 that accommodates the wafer 15 therein, the flange portion 26 having an open surface 161 provided on the front surface for loading and unloading the wafer 15 from the carrier 16, and the open surface 161. A cover 17 for sealing is provided. As shown in FIG. 3A, shelves 18 for mounting a plurality of wafers are provided on the inner wall surface of the carrier 16 at predetermined intervals in the vertical direction.

In addition, a top flange 20 that is an engaging portion with the FOUP transport robot when automatically transported by a FOUP transport robot represented by OHT (Overhead Hoist Transport) is provided on the upper part of the FOUP 13. Further, a handle 21 (FIG. 1) is provided on the side of the carrier 16 as a handle when the FOUP 13 is manually conveyed. As a result, the FOUP 13 is sealed with the wafer 15 accommodated therein, and can be transferred automatically or manually between the processing apparatuses. 3B is a diagram showing a surface of the cover 17 facing the FIMS door 12, and FIG. 3C is a diagram showing a surface of the cover 17 that contacts the carrier 16, and the cover 17 Is fitted with the carrier 16 on the open surface 161 of the carrier 16 to make the inside of the FOUP 13 a sealed space.

On the outer surface of the FOUP cover 17, that is, the surface facing the FIMS door 12, the cover 17 is attached to the carrier 16 by a positioning hole 22 for positioning the cover 17 with respect to the FIMS door 12 and a latch key 23 provided in the load port 2. A latch key hole 24 is provided for engagement / disengagement. A lock mechanism 25 is provided on the upper and lower edges of the cover 17 for engaging the cover 17 with a flange portion 26 provided on the periphery of the open surface 161 of the carrier 16. The lock mechanism 25 is interlocked with the latch key hole 24. By rotating the latch key hole 24 to the left and right with the latch key 23 provided on the FIMS door 12, the lock mechanism 25 can be operated in a locked state and an open state. Yes.

On the inner surface of the FOUP cover 17, that is, the surface in contact with the open surface of the carrier 16, the sealing material 27 for maintaining the hermeticity in the FOUP 13 and the edge of the wafer 15 accommodated in the FOUP 13 are horizontally arranged. A holding member 28 is provided for pressing and fixing. With this holding member 28, the wafer 15 inside the carrier 16 is fixed on the inner wall of the carrier 16 and the holding member 28 in a state of being placed on the shelf 18. Is suppressed. Information on these detailed dimensions and the like is defined by the SEMI standard, which is a standard related to semiconductor manufacturing.

According to an embodiment of the present invention, an atmosphere replacement device (“purge port”) that replaces the atmosphere of FOUP (internal gas) is designed to be incorporated into a load port (eg, load port 2 illustrated in FIG. 4). ing. Such a purge port is shown at 40 in the drawing. FIG. 5 is a cross-sectional view of the purge port 40 for purging the inside of the FOUP 13 with a purge gas (inert gas), and FIG. It is a perspective view about the FIMS door 12 periphery arrange | positioned in FIG.

According to the features of the embodiment of the present invention, the purge port 40 includes a purge plate 41 for supplying a purge gas (inert gas) to the FOUP 13. When not operating, the purge plate 41 is stored in a lower retracted position (the state shown in FIG. 5). For the purge operation, the purge plate 41 advances through the insertion hole 66 (FIG. 6) to the atmosphere replacement position above the retracted position. According to the feature of the embodiment of the present invention, in this advanced position, the purge plate 41 is integrated with the FIMS door 12 (which is pre-mounted with the cover 17 of the FOUP 13 as illustrated in FIG. 9). And the open surface 161 of the FOUP 13. Preferably, in this advanced position, the surface of the purge plate 41 (surface from which purge gas is ejected) is parallel or substantially parallel to the surface opening surface 161 of the purge plate 41 (which may be an inclination angle of plus or minus 20 degrees or less). 9) The purge plate 41 is placed in a posture (orientation) facing the inside of the open surface 161 (non-peripheral portion, preferably the central portion of the open surface 161). In this facing posture, the purge plate 41 performs a purge operation. That is, a substantially uniform, low-speed purge gas is ejected from the surface of the purge plate 41, forms a laminar flow (see the black arrow in FIG. 9), flows into the container 13, and the atmosphere of the container 13 is purged. Is done. The outflow surface of the purge plate 41 may have a shape corresponding to the inside (preferably the central portion) of the open surface 161 of the carrier 16. For example, in the illustrated embodiment, the purge plate 41 is substantially rectangular. The vertical and horizontal dimensions of the purge plate 41 are preferably smaller than the vertical and horizontal dimensions of the open surface 161 of the carrier 16 in consideration of fluid (purge gas) diffusion, and the inert gas from the purge plate 41 contains the carrier open surface 161. It is preferable to flow in as a laminar flow into the central part of (see FIG. 9).

Efficient atmospheric gas replacement is realized by the purge plate 14 having such a structure and arrangement. That is, the laminar inert gas (see the black arrow shown in the carrier 16 in FIG. 9) flowing out from the outflow surface of the purge plate 41 and flowing through the center of the carrier 16 is the air in the carrier (the carrier 16 in FIG. 9). (See the white arrow shown in the figure) is extruded in a laminar flow state between the peripheral edge of the purge plate 41 and the peripheral edge of the open surface 161 of the carrier 16, and mixing and stirring of the purge gas (inert gas) and air in the carrier 16 Can be reduced as much as possible. The purge gas (inert gas) here may include dry air in addition to nitrogen, argon, neon, and krypton.
Further, the purge port 40 advances the purge plate ascending mechanism 42 that moves the purge plate 41 back and forth (up and down movement) between the operating position (atmosphere replacement position) and the standby position (storage position), and the FIMS door 12. A FIMS door drive mechanism 43 that moves backward and a control unit 46 that controls each component of the purge port 40 are provided.

In the purge port 40 of the preferred embodiment, the purge port opening 44 provides a place where the purge plate 41 performs purging of the FOUP 13 (atmosphere replacement operation). The purge port opening 44 is also used as a place where the transfer robot 4 unloads / loads the wafer 15 in the FOUP 13. The purge port opening 44 has an opening area through which the flange portion 26 of the FOUP 13 placed on the stage 14 can pass, similarly to the port opening of a normal load port (for example, the load port 2 shown in FIG. 4). Have. In one operation step of the loading sequence, the FOUP 13 placed on the stage 14 passes through the inlet of the purge port opening 44, encounters the FIMS door 12 waiting at a predetermined position of the opening 44, and the position, cover 16 Is removed from the FOUP 13 and attached to the FIMS door 12 (ie, integrated into the FIMS door 12). Further, in order to prevent or suppress direct fluid communication between the adjacent mini-environment space unit 3 and the purge port opening 44, the mini-environment space includes upper and lower inner walls 45 ( The partition formed by 45a, 45b, 45c, and 45d shown in FIG. 6 is isolated from the internal space of the purge port 40 (that is, fluid communication is suppressed through a gap).

An insertion hole 66 having a sufficient area for the purge plate 41 to pass through is formed in the lower inner wall 45d of the purge port opening 44, and the purge plate 41 is moved to the operating position (atmosphere replacement) through the insertion hole 66. Position) and a standby position (storage position). In the illustrated embodiment (see FIGS. 5 and 6), the high clean air inside the mini-environment space unit 3 is located at the periphery of the FIMS door 12 (FIMS door 12 and

inner walls

45a, 45b, 45c) above the insertion hole 66. , 45d) and flows out to the outside. This flow of highly purified air becomes an “air curtain” or “air door”, and the low clean air outside the process apparatus reaches the purge plate 41 that is in the standby position (storage position) through the insertion hole 66. Therefore, it is not necessary to provide a lid member that covers the insertion hole 66, but if desired, a lid member that covers the insertion hole 66 so that it can be opened and closed is provided so that low clean air from the insertion hole 66 to the inside can be removed. Intrusion can be reliably prevented.

Also, if the gap between the

inner walls

45a, 45b, 45c and the peripheral edge portion of the FIMS door 12 is too large, a large amount of highly purified air in the mini-environment space unit 3 flows out through the gap, Since the internal pressure inside the environment space unit 3 does not increase and the cleanliness may not be maintained, a flange panel 65 is provided on the inner wall to limit the outflow of highly purified air to the outside of the mini environment space unit 3. Is provided. The flange panel 65 is provided on substantially the same plane as the FIMS door 12 facing the FOUP 13 (see FIG. 9), and the flange panels corresponding to the

inner walls

45a, 45b, 45c are in close contact with each other. In the specific examples of FIGS. 6 and 9, the FIMS door 12 and the flange panel 65 are arranged with a gap of about several mm, and a highly clean air outflow adjustment function is realized by this gap. That is, an appropriate amount of highly clean air inside the mini-environment space unit 3 flows out of the gap, and the internal pressure inside the mini-environment space unit 3 is maintained, and the low pressure from the outside is maintained. Infiltration of clean air is also effectively prevented.

Next, a specific example of the purge plate will be described in detail with reference to FIGS. The purge plate 41 is supported by a column 47 fixed to a bracket 52 (FIG. 5) attached to the moving element of the purge plate ascending mechanism 42, and can be moved up and down in conjunction with the raising and lowering operation of the purge plate ascending mechanism 42. It has become. The support 47 is in the form of a hollow pipe, and a piping path 39 through which an inert gas flows is inserted. This piping path 39 (FIG. 7) is connected to the internal piping 48 of the purge plate 41 so that the inert gas can be supplied to the purge plate 41.

The shape and size of the purge plate 41 are preferably designed based on the shape and size of the open surface 161 of the FOUP 13 that faces the purge plate 41. As a specific example, as shown in FIGS. 7 and 8, the purge plate 41 has a thin rectangular parallelepiped shape, and an inert gas introduced from one end is two-dimensionally arranged therein (for example, 2 A pipe 48 having a branching shape to be distributed to a large number of jet ends (in a dimensional matrix arrangement), and provided at each jet end (pipe outlet) of the pipe 48 to reduce the flow rate of the inert gas sent, In addition, it has a two-dimensional array of ejection suppression elements 49 that disperse the inert gas over a wide range. By making the pipe 48 into a number of branched shapes, the inert gas jet output introduced from one end of the pipe 48 is distributed to the branched jet ends, so that the inert gas jetted from the jet ends can be reduced. It works to reduce momentum.

Making the pipe 48 into a branched shape can be realized by various methods. For example, it may be branched to a tube material made of polyurethane, PTFE (polytetrafluoroethylene) resin or the like via a joint, or a branched shape may be formed by joining a pipe made of stainless steel material or the like. .

The ejection suppression element 49 attached to each ejection end of the pipe 48 can be realized by various materials having a required ejection suppression function for the purge gas to be used, and can be preferably configured by a porous material. For example, it can be realized by a PTFE fine particle bonded composite member, a sintered metal, sintered glass, open cell glass, a laminated filter medium, or an air filter member having a hollow fiber membrane as a filter medium. In the case of the porous ejection suppressing element 49, the flow rate of the inert gas is reduced by passing the inert gas through a narrow gap or a fine hole in the ejection suppressing element 49, and the ejection direction of the inert gas is widespread. The inert gas is uniformly supplied into the purge plate 41. Further, the porous ejection suppressing element 49 can remove dust mixed in the inert gas when flowing through the pipe. In the case of the porous jet suppression element 49, since the fine structure of porous is used for jet suppression, the jet suppression element having the required jet suppression capability can be realized in a compact manner.

Preferably, a rectifying plate 50 having a purge gas (inert gas) outflow surface is attached to a surface of the purge plate 41 facing the carrier opening. The rectifying plate 50 constitutes a protective cover for the purge plate 41, and a two-dimensional hole array or hole mesh in which a large number of openings or holes are arranged vertically and horizontally on the outflow surface in order to discharge the purge gas to the outside of the purge plate 41. Is formed. Each hole of the hole mesh has a rectifying function that regulates the flow direction of the purge gas. As a specific example, the current plate 50 can be formed of a punching plate in which punched holes are uniformly arranged two-dimensionally. The material of the purge plate 41, the support column 47, and the protective cover 50 is desirably a stainless material in terms of physical properties and cost, but a resin material such as a PTFE material may be used. With this configuration, the inert gas sent to the purge plate 41 is filled into the purge plate 41 by the ejection suppression element 49 and flows into the carrier 16 as a laminar flow widely and evenly through the hole mesh of the rectifying plate 50. Will be allowed to.

In addition to the air filter member described above, the ejection suppression element 49 is a porous material such as an open-cell foamed resin, a stainless wire mesh, a sintered metal, or a ceramic porous body. Materials that do not generate can be used. In FIG. 7, the ejection suppression element 49 is composed of a porous element that is individually attached to each ejection end of the pipe 48. As an alternative form, as shown in FIG. 8, it may be constituted by a flat plate-like porous ejection suppressing element 49 (that is, a porous sheet) mounted between the purge plate 41 and the rectifying plate 50 (protective cover) ( In this case, it is not necessary to provide an individual ejection suppressing element 49 at each ejection end of the pipe 48). In addition to the plate-like porous ejection suppressing element 49, the ejection direction of the inert gas ejected from the purge plate 41 is regulated (rectified) by the mesh-shaped pores, and flows into the carrier 16 as a laminar flow. If the reinforcing rectifying plate 79 is disposed between the ejection suppressing element 49 (porous sheet) and the purge plate 41, not only the rectification but also the effect of reinforcing the porous ejection suppressing element 49 is obtained.

Next, a purge plate raising mechanism 42 that moves the purge plate 41 up and down will be described with reference to FIG. The purge plate ascending mechanism 42 rotates in conjunction with the rotation of the motor 51 as a drive source, the feed screw 53 that moves the bracket 52 to which the support column 47 is attached, and the lifting / lowering operation of the bracket 52. The guide rail 54 which guides is provided. The feed screw 53 rotates in conjunction with the rotation of the motor 51, and the bracket 52 attached to the moving element of the feed screw 53 moves up and down by a predetermined amount according to the rotation angle of the motor 51.

Accordingly, the purge plate 41 can be reciprocated (lifted) between the operating position (atmosphere replacement position) and the standby position (storage position). In this embodiment, the motor 51 and the feed screw 53 are used as the elevating mechanism. Instead, any appropriate mechanical reciprocating mechanism such as an air cylinder, a hydraulic cylinder, or a cam link mechanism is used. Is possible. Further, in this embodiment, when the purge plate 41 is not in operation, the purge plate 41 is accommodated in the lower portion of the purge port opening 44 and is raised to the atmosphere replacement position during the purge operation so that the purge plate 41 is reciprocated up and down. Designing. This is a preferable form in that it can be realized in a space-saving manner, and it is easy to ensure compatibility with an existing load port. However, if desired, it can be replaced with an upper portion or a side portion of the purge port opening 44 instead. The purge plate 41 may be reciprocated between the advanced position and the retracted position by the drive mechanism.

The control unit 46 that performs the control necessary for the purge operation (including control of the reciprocating motion of each drive mechanism, the flow rate of inert gas, the supply time, and the supply timing) is a control BOX 70 (FIG. 12) inside the main body of the purge port 40. ) Is provided inside. As shown in FIG. 12, the inert gas is supplied from the outside of the purge port 40 into the control unit via the supply path, and is introduced into the purge plate 41.

The inert gas introduced into the purge plate 41 may be supplied from factory equipment in which the purge port 40 as an atmosphere replacement device is installed, or a container storing the inert gas in the purge port 40 may be provided. It can also be provided. A purge gas (inert gas) using factory equipment or a stored container as a supply source 69 is introduced into the control BOX 70 through a supply path, and a pressure regulator 71, a pressure sensor 72, and an electromagnetic valve 73 provided in the control BOX 70. After that, the structure is introduced into the purge plate 41. The pressure regulator 71 adjusts the pressure on the outlet side with respect to the fluctuating pressure of the supply source, and the pressure sensor 72 measures the pressure of the inert gas sent from the outlet side of the pressure regulator 71. The alarm signal is transmitted to the control unit 46 when a high pressure or a low pressure is set with respect to preset upper and lower thresholds.

The electromagnetic valve 73 opens and closes the valve through which the inert gas flows in response to an input signal sent from the control unit 46, and has a predetermined timing according to a procedure stored in advance in a storage device provided in the control unit 46. Thus, the inert gas can be supplied for a predetermined time. Each supply path from the electromagnetic valve 73 to the purge plate 41 is provided with a needle valve 74, and the flow rate of the inert gas can be adjusted accurately. With this configuration, the inert gas introduced into the control BOX 70 via the supply path is controlled to a predetermined pressure and flow rate, and then supplied to the purge plate 41 of the inert gas for a predetermined time at a predetermined timing.

The inert gas supply time may be determined in advance by determining a suitable time by a test, and the start and stop of supply may be controlled by a timer provided in the control unit 46 (timer method). As an alternative, a sensor for detecting the inert gas concentration may be installed at a suitable location of the purge port 40, and the supply may be stopped when the inert gas concentration in the FOUP 13 reaches a specified value (sensor method). . Further, the sensor may measure the concentration of the inert gas used as the purge gas. Alternatively, the same effect can be obtained by using a sensor that measures a relatively inexpensive oxygen concentration. . When an oxygen concentration sensor is used, control is performed to stop the supply of purge gas when the oxygen concentration in the FOUP 13 falls below a specified numerical value.

In the case of an atmosphere replacement device that supplies an inert gas directly into the carrier 16 from the pipe 48 in order to allow the inert gas to flow into the carrier 16, the inert gas flowing into the carrier 16 can be increased by increasing the flow rate of the inert gas. The amount of active gas also increased, and it was expected that the atmosphere could be replaced in a short time. However, in reality, the dust adhering to the back surface of the wafer 15 accommodated in the carrier 16 and the dust accumulated in the carrier 16 are blown off by the injecting force of the inert gas. The inventor of the present application has confirmed a phenomenon (stirring phenomenon) in which the particles collide with the processing surface of the wafer 15 and damage the processing surface.

Further, the inert gas flow having a high flow velocity collides with the wall surface in the carrier 16 and then flows out to the outside or entrains air from the outside, so that the inert gas concentration in the carrier 16 does not increase. There is also a possibility of causing a malfunction. Conversely, lowering the flow rate of inert gas reduces problems such as scattering of dust and outflow of inert gas, but it also reduces the flow rate, resulting in a great deal of time for atmosphere replacement. The inventors of the present invention have also confirmed that the oxidation of the surface of the wafer 16 progresses until the atmosphere replacement is completed, leading to a decrease in yield (oxidation phenomenon). Furthermore, the agitation phenomenon and the oxidation phenomenon described above are conspicuous in a conventional atmosphere replacement device in which an inert gas is blown into the carrier 16 using a nozzle that is a fluid element that blows out at a higher flow rate of the inert gas. Was confirmed. According to the present invention, a purge port (atmosphere replacement device) is provided with a non-nozzle type purge plate, and a slow purge gas flow is realized by this purge plate. The inventor of the present application has found that the agitation phenomenon and the oxidation phenomenon can be sufficiently suppressed according to such a novel atmosphere replacement device with a purge plate.

For example, in the purge plate 41 according to a preferred embodiment, the purge gas pipe 48 is composed of a number of branch pipes, and an inert gas introduced from one introduction end (pipe inlet) is connected to a plurality of ejection ends (pipe outlets). ). Then, a discrete porous ejection suppressing element 49 is provided at the tip of each ejection end (FIG. 7), or a sheet-like porous ejection suppressing element 49 that covers all the ejection ends is disposed (FIG. 8). . Furthermore, the inert gas is poured toward the open surface 161 of the carrier 16 through the current plate 50 in which the hole mesh is formed. In this way, the purge plate 41 prevents the stirring phenomenon and prevents the dust staying in the carrier 16 from scattering. In addition, a short period of purging (atmosphere replacement) is realized by supplying an inert gas in an amount necessary for atmosphere replacement within a predetermined time from the purge plate 41, which is a uniform planar laminar gas generation plate, into the carrier. The oxidation phenomenon of the substrate surface (wafer surface) is suppressed.

In the purging operation of the preferred embodiment, the inert gas diffused inside the purge plate 41 is rectified by the rectifying plate 50 having mesh holes or two-dimensional array holes, and is substantially uniform with respect to the opening surface 161 of the carrier 16. A laminar flow having a flow velocity is supplied into the carrier 16. The inert gas supplied to the inside of the carrier 16 gradually flows into the inside of the carrier 16 through a gap between the wafers 15 accommodated in the inside of the carrier 16, thereby filling the contaminants and the inside staying on the surface of the wafer 15. The clean air that has been discharged is discharged from the periphery of the flange portion 26 of the carrier 16 so as to be pushed out by the inert gas, and the atmosphere replacement inside the carrier 16 proceeds (see FIG. 9).

In the atmosphere replacement position, the purge plate 41 is disposed at the center with respect to the purge port opening 44 (therefore, the vertical center line of the open surface 161 of the carrier 16 coincides with the vertical center line of the purge plate 41). This is desirable because the clean air inside the carrier 16 pushed out by the inert gas is uniformly discharged from the periphery of the purge port opening 44 to the outside. However, even if the purge plate 41 is arranged at the non-central portion of the purge port opening 44, the stirring is similarly suppressed by adjusting the flow rate and flow velocity, and an inert gas pushing effect can be obtained.

As described above, in order to allow the inert gas to flow in a laminar flow from the purge plate 41 toward the open surface 161 of the carrier 16, the rectifying plate 50 that is a purge gas output plate is constant with respect to the open surface 161. It is preferable to have an inert gas outflow surface of a proportion of 7 shows an outflow surface due to a plate material (round hole punching plate) having a large number of circular holes, and FIG. 8 shows an outflow surface due to a net plate material (square hole punching plate). The area ratio of the outflow surface occupying the purge plate preferably has an appropriate size. When the horizontal dimension of the current plate 50 is A, the vertical dimension is B, the horizontal dimension of the outflow surface of the purge plate is a, and the vertical dimension is b, the ab / AB ratio (relative to the current plate area). The ratio of the outflow surface area) is preferably in the range of 50% to 100%. The area of the rectifying plate 50 is preferably 10% or more and 60% or less with respect to the area of the open surface 161 of the carrier 16, and the outflow surface area of the rectifying plate 50 is 5% with respect to the area of the carrier 16 opening surface. Above, 50% or less is preferable.

The FIMS door 12 is disposed at a position that effectively adjusts and inhibits the high clean air supplied from the fan filter unit 5 of the mini-environment space unit 3 from flowing into the inside of the carrier 16 when the atmosphere is replaced. It is preferable that the inert gas concentration in the carrier 16 by purging can be efficiently increased by the high clean air inflow adjustment / suppression function.

The purge port 40 can be configured such that highly purified air having a flow rate adjusted using the flange panel 65 flows out through the purge port 40 through the gap between the FIMS door 12 and the inner wall 45. FIG. 9 shows the flow of the inert gas, highly clean air, and air in the carrier 16 when the atmosphere is replaced in such an embodiment. FIG. 9A is a cross-sectional view seen from the side. (B) is a cross-sectional view seen from above. As shown in FIG. 9, the purge port 40 has a highly clean air passage 121. That is, in FIG. 9, an appropriate amount of highly purified air from the mini-environment space unit 3 (not shown) on the right side passes through the gap provided between the FIMS door 12 and the flange panel 65, and enters the outside of the apparatus. To leak. For this reason, the air inside the carrier 16 pushed out by the inflow of the inert gas is attracted or sucked by the high clean air flow in the high clean air passage 121 and exhausted outside the apparatus. Therefore, it is not necessary to add a dedicated device for sucking (exhausting) air remaining inside the carrier 16 during atmosphere replacement. Thus, the highly clean air passage 121 formed by the gap has a function of promoting the atmosphere replacement inside the carrier.

During this atmosphere replacement, a small amount of inert gas may flow out of the device together with highly clean air. However, highly purified air containing inert gas discharged outside the device is The flow will immediately flow out of the factory through the punching holes in the floor and will not adversely affect the human body or other equipment.

Further, the air flow rate adjusting function performed by the highly clean air passage 121 of the purge port 40 is such that the flange portion 26 of the carrier 16 and the periphery of the purge port opening 44 are brought close to each other with almost no gap when the wafer 15 is loaded / unloaded. It can also be applied to other load ports. That is, the carrier 16 mounted on the stage 14 is slightly retracted (moved by a predetermined distance in a direction away from the mini-environment space unit 3) to form a gap between the flange portion 26 and the purge port opening 44 periphery. It is only necessary to provide a mechanism (by which the highly clean air passage 121 is formed) and to let the air inside the carrier 16 flow out of the apparatus together with the highly clean air from the formed gap (see FIG. 9).

If desired, a suction mechanism for sucking the atmosphere inside the carrier 16 may be provided in addition to the purge plate 41 for supplying an inert gas. For example, the suction mechanism is arranged around the purge plate 41 in the center at a position facing the open surface 161 of the carrier 16 or at a position where the purge plate 41 faces the carrier 16 open surface 161 and is shifted from the center. Next, it may have the same shape as the purge plate 41, or may be a form in which suction is performed from the suction port provided in the bottom of the carrier 16 according to the SEMI standard.

Next, the operation of the purge port 40 will be described in detail with reference to FIG.
The wafer 15 that has been processed in the processing apparatus 1 is moved to the purge port 40 that also has the function of a load port by the transfer robot 4 provided in the mini-environment space unit 3 after the processing is completed. In other words, the transfer robot 4 carries it in a predetermined shelf 18 in the carrier 16 disposed in the purge port 40 (load port). Refer to FIG. In this wafer transfer mode, the purge plate 41 is in the retracted position (storage position), and the upper portion of the insertion hole 66 through which the purge plate 41 passes to move to the advanced position is occupied by the carrier 16 for wafer transfer. (Therefore, the purge plate 41 cannot be raised). In addition, an appropriate amount of high cleanliness is always passed through the gap between the purge port 40 (between the flange portion 26 and the flange panel 65) from the mini-environment space unit 3 of "positive pressure" (atmospheric pressure higher than the surroundings) to the outside of the apparatus 1. Since the air is flowing out, the inside of the device 1 and the inside of the carrier 16 are not contaminated by the low clean air outside the device 1. Note that, in the wafer transfer mode to the FOUP shown in FIG. 11A, the FIMS door 17 has an integrated form with the FOUP cover 17 attached, and is retracted to a position below the purge port opening 44 (retracted position). is doing.

When the wafer transfer by the transfer robot 4 is completed, the stage drive mechanism 29 slightly retracts the stage 14 on which the carrier 16 is placed in a direction away from the purge port opening 44 (that is, a direction away from the mini-environment space unit 3). . In conjunction with the backward movement of the stage 14, the FIMS door 12 (which is in an integrated state where the FOUP cover 17 is attached at this time) has a height corresponding to the open surface 161 of the carrier 16 by the FIMS door lifting mechanism 55. Ascend to (advance position). In this way, a space (operating area of the purge plate 41) is ensured between the open surface 161 of the carrier 16 and the FOUP cover 17 (mounted on the FIMS door 12). Refer to FIG. Note that the movement of the purge port 40 by the minute backward movement performed by the stage 14 also has the purpose of moving the carrier 16 to a position where the atmosphere replacement by the purge port 40 is efficiently performed.

Further, the stage 14 moves backward by a slight movement, but there is a gap of about 5 mm between the flange portion 26 provided on the periphery of the carrier 16 and the inner wall 45 provided on the periphery of the purge port opening 44. The high clean air inside the mini-environment space unit 3 flows out of the processing apparatus through the gap, thereby preventing the low clean air from flowing into the mini-environment space unit 3 from the outside of the apparatus.

Thereafter, the purge plate 41 is raised to a predetermined position (operating position) with respect to the open surface of the carrier 16 by the purge plate ascending mechanism 42, and the inert gas can be supplied into the carrier 16. Refer to FIG. In the operating position, the purge plate 41 is located between the FOUP carrier 16 and the FIMS door 12, and as described above (see FIG. 9), a laminar purge gas is generated and sent toward the FOUP carrier 16 in a slow manner. FOUP purging (atmosphere replacement operation) is performed.

When the FOUP purging at the operating position is completed (for example, when the inert gas is supplied into the carrier 16 for a predetermined time), the purge plate 41 is moved to the original standby position by the purge plate ascending mechanism 42. Refer to FIG. If the inert gas continues to be supplied while the purge plate 41 is lowered to the predetermined standby position (retracted position), the total time required for purging the FOUP 13 can be shortened. A decrease in the concentration of the inert gas can be suppressed, which is preferable. For this purpose, as an alternative or a combination, an auxiliary nozzle 68 (FIG. 5), which will be described later, may be used to replenish inert gas from there during this purge plate lowering mode.

When the purge plate 41 finishes descending, the stage 14 is advanced to a position where the carrier 16 on the stage 14 is docked with the FOUP cover 17. Refer to FIG. In this docking position, the FIMS door 12 removes the FOUP cover 17 that has been mounted, and the carrier 16 is locked with the cover 17 by means of a latch key 23b provided therein, so that the FOUP 13 is sealed. Thereafter, the stage 14 performs the backward movement to the transfer position with the FOUP transfer robot or the OHT, whereby all the operations (loading and purging sequences) of the purge port 40 are completed. Refer to FIG. *

Further, depending on the type of the processing apparatus 1 and the type of process, an attempt is made to increase the internal pressure of the mini-environment space unit 3 and increase the cleanliness by increasing the rotational speed of the fan 8 provided in the fan filter unit 5. Some will do. When the purge port 40 is used in the environment of such a processing apparatus, strong air (high speed) high clean air flows into the periphery of the purge plate 41 from the gap of the flange portion 26 at the end of the FIMS door 12 carrier 16 at the time of atmosphere replacement. Therefore, the laminar flow of the inert gas is disturbed by the flow of the highly clean air, and the atmosphere replacement may not be sufficiently performed. This can be prevented by providing a mechanism that adjusts the gap of the atmosphere replacement device to be small and adjusts the amount of highly purified air flowing from there to an appropriate amount. Alternatively, in place of the gap adjustment type high clean air amount adjusting mechanism, the following sealing mechanism with improved fluid shielding with the mini-environment space unit 3 can be used.

Specifically, a labyrinth seal structure formed so as to shield the gap between the FIMS door 12 and the flange panel 65 in a non-contact manner on the side of the periphery of the FIMS door 12 facing the mini-environment space unit 3. This is possible by attaching the shield cover 67a or the shield cover 67b. FIG. 14A is a perspective view showing a specific example in which the shield cover 67a is attached to the FIMS door 12, and is a partially cutaway view of the FIMS door 12 with the upper left portion viewed from the carrier 16 side.

The end of the shield cover 67a facing the carrier 16 forms a U-shaped labyrinth structure, and is fitted in a non-contact manner with the open surface side peripheral edge of the flange panel 65, so that the carrier 16 at the time of atmosphere replacement The entrance of highly clean air from inside the mini-environment space unit 3 is blocked. Further, in the configuration in which the mapping sensor 32 is attached to the periphery of the FIMS door 12, the sensor attachment portion 33 for moving forward and backward toward the inside of the carrier 16 is usually disposed, and therefore the shield cover 67 a is provided. In order to make the shape of the sensor mounting portion 33 not interfere with the operation of the sensor mounting portion 33, a sensor intrusion hole is provided in the 67a.

Further, since the FIMS door 12 to which the shield cover 67a is attached can be moved up and down in the vertical direction by the FIMS door lifting mechanism 55, the shield cover 67a attached to the FIMS door 12 and the flange cover 65 on the inner wall face each other. About a part, it is preferable to set it as the mutually non-contact labyrinth structure which makes one edge part a recessed part and makes the other corresponding edge part a convex part. Thereby, the FIMS door 12 and the shield cover 67a are operable. Further, by employing a labyrinth seal structure in which the concave portion and the convex portion are not in contact with each other, there is no possibility of dust generation, and the cleanliness inside the carrier 16 can be maintained.

Further, the FIMS door drive mechanism 43 guides the FIMS door 12 along the guide rail 62 and is movable with respect to the carrier 16 in a direction away from and within a prescribed range of the guide rail 62 (see FIG. 10), by providing a shield cover 67b as shown in FIG. 13 and FIG. 14B, the same effect as the specific example shown in FIG. 14A can be obtained.

Here, the FIMS door drive mechanism 43 will be described with reference to FIG. The FIMS door drive mechanism 43 is fixed to a moving element 57 of a feed screw mechanism 56 provided in the FIMS door lifting mechanism 55, and is moved up and down by the FIMS door lifting mechanism 55, and is attached to the base member 58. The motor 60 that is a driving source for moving the door 12 forward and backward, and the feed screw 61 that rotates in conjunction with the rotation of the motor 60 to move the FIMS door 12 fixed to the mover 63 forward and backward, guide the movement of the FIMS door 12. It consists of a guide rail 62.

Further, the guide rail 62 is attached to brackets 64 fixed to the left and right ends of the base member 58. In addition, the sensor attachment portion 33 is rotatably attached to the bracket 64, and the movement of the mapping sensor 32 into the carrier 16 is enabled by the operation of the sensor drive mechanism 34. In the specific example of FIG. 10, the motor 60 feed screw 61 is used as the FIMS door drive mechanism 43, but another type of drive mechanism such as an air cylinder, a hydraulic cylinder, or a cam link mechanism is used instead. It's also good.

13 is a perspective view of the periphery of the FIMS door 12 having a shield structure as viewed from the mini-environment space unit 3 side, and FIG. 14B is a perspective view showing the shield structure, and the carrier 16 side of the FIMS door 12 It is the partially cutaway figure which lacked the front view upper left part seen from the front. The shield cover 67b is fixed to brackets 64 provided at both ends of the FIMS door 12, and has a gate-shaped opening shape corresponding to the open surface of the flange panel 65. The inside of the open surface is the FIMS door 12. In addition, the wafer 15 transported by the wafer transport robot 4 has a sufficiently large area. In addition, a sensor mounting portion 33 is rotatably disposed on the bracket 64 so that the mapping sensor 32 attached to the sensor mounting portion 33 can move forward and backward toward the inside of the carrier 16 to perform wafer mapping. It has become. For this reason, it is considered that the shield cover 67b has an attachment position and shape that do not interfere with the rotation operation of the sensor attachment portion 33.

Further, since the bracket 64 for attaching the shield cover 67b can be moved up and down in the vertical direction by the FIMS door lifting mechanism 55, the shield cover 67a is provided at the opposite ends of the shield cover 67b and the flange cover 65. In the same manner as above, the bracket 64 and the shield cover 67b can be operated by adopting a labyrinth structure in which one end is a recess (a U-shape) and the corresponding other end is a protrusion. Further, by making the concave and convex portions non-contact with each other, no dust is generated, and the cleanliness inside the carrier 16 can be maintained.

Further, as shown in FIG. 13, the FIMS door 12 can be moved within the range guided by the guide rail 62 by the FIMS door drive mechanism 43, so that the FIMS door 12 is located at the position farthest from the carrier 16. When reaching, the peripheral edge of the FIMS door 12 and the end of the shield cover 67b are non-contact fitted, so that the gap between the FIMS door 12 and the shield cover 67b is shielded (in the deepest labyrinth seal state). Securing), a small amount of highly purified air in the positive-pressure mini-environment space unit 3 flows out of the apparatus, thereby preventing the entry of external air.

In addition, the opening amount of the gap between the FIMS door 12 and the shield cover 67b is changed (the depth of the labyrinth seal state is changed) by moving the FIMS door 12 within the operation range guided by the guide rail 62. Thus, depending on the position of the FIMS door 12, the inflow amount of highly clean air from the mini-environment space unit 3 can be adjusted.

FIG. 14B is a view showing a point in time when the FIMS door 12 integrated with the cover 17 is at an intermediate position on the guide rail 62, and will be described based on this figure. The highly purified air in the mini-environment space unit 3 maintained at a higher pressure than the outside air passes through the gap provided between the edge of the carrier 16 and the flange panel 65 from between the FIMS door 12 and the shield cover 67b. When flowing out, the highly clean air in the carrier 16 is also attracted and flows out, which has the effect of increasing the efficiency of atmosphere replacement. With this structure, even if the rotational speed of the fan filter unit 5 is changed due to the convenience of the processing apparatus 1 and the internal pressure in the mini-environment space unit 3 is changed, the optimal amount of high clean air can be easily discharged. Therefore, it is not necessary to make a modification in accordance with the change of the internal pressure, which has been conventionally performed.

Furthermore, by making the FIMS door 12 movable back and forth, the position of the purge plate 41 located between the carrier 16 and the FIMS door 12 can be set with respect to the carrier 16 opening surface, and the optimum inert gas supply amount is increased. And the purge plate position, and the optimum purge plate area and purge plate position can be searched.

Note that the SEMI standard, which is a standard for semiconductor manufacturing equipment in general, has a provision that the protruding portion from the wall surface forming the mini-environment space unit 3 is within 100 mm, but in this embodiment, the shield cover 67a and The amount of protrusion of the 67b toward the mini-environment space unit 3 is within 100 mm, and is compliant with the SEMI standard.

By the way, after the supply of the inert gas by the purge plate 41 is completed, the open surface 161 of the carrier 16 is sealed by the cover 17 to complete all the atmosphere replacement operations. After the supply is completed, the cover 17 closes the open surface of the carrier 16 and then the oxygen concentration in the carrier 16 increases (means that the inert gas concentration in the carrier 16 decreases). This is a transient purge gas concentration lowering phenomenon accompanying the disappearance of the purge gas flow from the purge plate 41. This is because after the atmosphere replacement is completed, the remaining air that has not flowed out of the apparatus has diffused throughout the carrier 16, resulting in a decrease in the inert gas concentration in the entire interior, and the completion of the atmosphere replacement. Thereafter, it is considered that the air around the carrier 16 enters the carrier 16 in a short time until the open surface of the carrier 16 is sealed. When the purging time by the purge plate 41 is too short, this transient purge gas concentration lowering phenomenon occurs after the sealing operation (although the average value of the inert gas concentration in the carrier 16 does not substantially fluctuate), The concentration of the inert gas in the center of the plate decreases to below a specified value before stabilizing.

In order to suppress such a decrease in purge gas concentration, an auxiliary nozzle 68 as shown in FIG. 5 can be added to the atmosphere replacement configuration of the above embodiment. The auxiliary nozzle 68 is provided on the inner wall 45 provided on the periphery of the purge port opening 44. Then, from the point in time when the purge plate 41 starts moving to a predetermined standby position (storage position) (at the start of lowering) until the carrier 16 is sealed by the cover 17, the carrier 16 and the cover 17 An inert gas is supplied toward The purge gas flow supply from the auxiliary nozzle 68 functions to compensate for the purge gas flow disappearance from the purge plate 41. The purge gas flow supply from the auxiliary nozzle 68 serves to shorten the total purging time necessary for the purge port 40 to achieve the required atmosphere replacement.

Thus, air can be prevented from entering the inside of the carrier 16 by filling the space surrounded by the carrier 16, the cover 17, and the

inner walls

45a, 45b, 45c with the inert gas. Further, by supplying the inert gas from the auxiliary nozzle 68, the inert gas concentration around the carrier 16 is ensured, and the phenomenon that the inert gas concentration inside the carrier 16 decreases below the reference value after the cover 17 is closed is suppressed. be able to.

The auxiliary nozzle 68 may be provided on any inner wall 45a-d on the periphery of the purge port opening 44. If the flow rate of the inert gas discharged from the auxiliary nozzle 68 is increased too much, the carrier 16 entrains the surrounding air, making it difficult to achieve a sufficient inert gas concentration. Therefore, it is preferable that the flow rate of the inert gas supplied from the auxiliary nozzle 68 is substantially equal to the flow rate of the inert gas supplied from the purge plate 41. Here, the shape of the inert gas outlet of the auxiliary nozzle 68 is preferably a slit having the same length as one side of the inner wall 45 of the purge port opening 44.

In addition to the above, the auxiliary nozzle 68 can also maintain the interior of the FOUP 13 in a highly clean atmosphere by supplying a dustless gas such as an inert gas or highly clean air when the cover 17 is opened. . That is, after the FOUP 13 is opened and until the forward movement by the stage drive mechanism 29 is completed, the FIMS door 12 is moved away from the carrier 16 by the FIMS door drive mechanism 43. As the door 12 moves away, the gap between the FIMS door 12 and the shield cover 67b gradually decreases, and the flow rate of highly clean air that flows out of the apparatus accordingly decreases.

As a result, low-clean air outside the apparatus may enter the inside of the carrier 16 through the gap between the flange portion 26 of the carrier 16 and the inner wall 45, and the inside of the carrier 16 may be contaminated with dust. Therefore, after the FOUP 13 is opened, the dust-free gas flows out from the auxiliary nozzle 68 between the carrier 16 opening surface and the cover 17 until the forward movement operation by the stage drive mechanism 29 is completed. Air is prevented from entering the inside of the carrier 16.

Next, the results of an atmosphere replacement test using the purge port 40 having the above-described embodiment will be disclosed. As shown in FIG. 15, the test is performed by installing a purge port 40 in a test clean booth (test mini-environment space unit 3) that forms the same mini-environment space unit 3 as the actual processing apparatus 1. The oxygen concentration inside the test FOUP 13 placed on the port 40 was measured. As the oxygen concentration meter 78, a zirconia oxygen concentration meter LC-450A manufactured by Toray Engineering Co., Ltd. was used. As the inert gas used for the atmosphere replacement, nitrogen gas having a purity of 99.99% or more generally used for the atmosphere replacement was introduced into the purge port 40 from the cylinder as the supply source 69 through the supply path.

The reason for measuring oxygen concentration instead of nitrogen concentration is that oxygen concentration measuring instruments are cheaper and easier to obtain than nitrogen concentration measuring instruments, and the inert gas used for atmosphere replacement is not limited to nitrogen. This is because it is possible to estimate the progress of the atmosphere replacement in the test FOUP 13 by measuring the oxygen concentration. Further, the present oxygen concentration measuring instrument LC-450A can also measure the humidity indicated by the dew point, and can be used even when dry air is used as an inert gas. The test FOUP 13 is composed of a carrier 16 and a cover 17 similar to a commonly used FOUP. The carrier 16 is provided with 25 shelves on which the wafer 15 is placed, but a tube 79 for collecting the internal atmosphere. An insertion hole for allowing insertion of the FOUP is different from a normal FOUP.

In the test, the wafers were placed on all the 25-stage shelves, and the oxygen concentration measurement position inside the test FOUP 13 was set near the 14th-stage shelf on the back side when viewed from the purge plate 41 during atmosphere replacement. As shown in FIG. 15, the oxygen concentration measuring device 78 sucks the atmosphere inside the test FOUP 13 through the tube 79 by the suction pump provided inside, and the oxygen in the sucked atmosphere by the detection means provided inside. Concentration was measured.

First, as a first test, an experiment was conducted to determine what is the preferable differential pressure between the inside of the test mini-environment space unit 3 and the external environment when performing atmosphere replacement. The internal pressure of the test mini-environment space unit 3 is adjusted by increasing / decreasing the number of rotations of the fan 8 provided in the fan filter unit 5 that feeds highly clean air. Since the inside of the mini-environment space unit 3 is generally kept at a positive pressure with respect to the external environment because the inside of the mini-environment space unit 3 is kept highly clean, the differential pressure with respect to the external environment is a negative pressure. Some cases are not tested. Further, the nitrogen gas is supplied only from the purge plate 41 and is not supplied from the auxiliary nozzle 68. The oxygen concentration inside the test FOUP 13 was set to 100 ppm (0.01%) or less from the viewpoint of preventing oxidation of the wafer surface placed inside.

In the test, the internal / external pressure difference of the test mini-environment space unit 3 was set to 3.5 Pa and 2.5 Pa, and when the nitrogen gas flow rate was supplied to each environment at 120 liters per minute for 110 seconds, The change in oxygen concentration when supplying for 80 seconds at 150 liters was examined.

FIG. 16 is a graph showing the test results. The vertical axis represents the oxygen concentration (ppm), the horizontal axis represents the elapsed time (seconds), and the time when the supply of nitrogen gas from the purge plate 41 to the inside of the carrier 16 is set to 0. Since it takes about 1 second until the internal atmosphere of the carrier 16 is completely sealed by the cover 17 after the supply of nitrogen gas is stopped, 81 seconds after the start of the supply, or 111 seconds or more are used for the sealed test. This represents the transition of the oxygen concentration inside the FOUP 13.

When nitrogen gas at a flow rate of 120 liters per minute is supplied for 110 seconds in an internal / external pressure difference of 3.5 Pa, the oxygen concentration at the time when the test FOUP 13 is sealed 111 seconds after the start of supply of nitrogen gas is up to 10 ppm. Although it has decreased and increased to 47.2 ppm 180 seconds after the start of supply (69 seconds after sealing), the target value is maintained below 100 ppm and is almost stable. In addition, when nitrogen gas having a flow rate of 150 liters / min was supplied for 80 seconds at an internal / external pressure difference of 80 Pa, the oxygen concentration dropped to 8.9 ppm 81 seconds after the start of supply, but 180 seconds had elapsed since the start of supply. It has risen to 262 ppm at the time. From this result, it is possible to increase the positive pressure of the internal / external differential pressure of 4 Pa by adjusting the flow rate of the inert gas and the supply time.

After the supply of the nitrogen gas is completed and the sealing of the test FOUP 13 is completed, the oxygen concentration increases under any conditions, but it can be seen that the higher the differential pressure, the larger the increase rate of the oxygen concentration. This is because when the purge plate 41 descends to the standby position after the supply of the nitrogen gas is completed, a part of the highly purified air flowing out from the test mini-environment space unit 3 flows into the carrier 16 from the upper part of the carrier 16. The cause is considered to be diffused throughout the test FOUP 13 even after the sealing is completed.

In addition, there is no significant difference in oxygen concentration immediately after the supply of nitrogen gas is stopped, and the target value is sufficiently satisfied at about 10 ppm in any differential pressure environment, but 150 liters per minute in an environment with a differential pressure of 3.5 Pa. In the test in which nitrogen gas was supplied for 80 seconds, the increase in oxygen concentration after sealing was large, 200 ppm at 150 seconds from the start of nitrogen gas supply (69 seconds after sealing), 180 seconds from the start of supply (99 seconds after sealing) At that time, it was 259 ppm. Further, in an environment where the internal / external differential pressure is 2.5 Pa, the oxygen concentrations at the time of 180 seconds elapse are 62.7 ppm and 30.8 ppm, and a result that sufficiently satisfies the target value is obtained.

Next, a test was performed to determine how much the pressure difference between the inside and outside of the test mini-environment space unit 3 affects the oxygen concentration after sealing the test FOUP 13 with the nitrogen gas flow rate and supply time constant. In the test, the internal / external differential pressure of the test mini-environment space unit 3 was set to 0 Pa, 1.0 Pa, 2.5 Pa, and 3.5 Pa, and for each internal / external differential pressure, nitrogen gas at a flow rate of 150 liters per minute was set to 110. After supplying for 2 seconds, the transition of the oxygen concentration inside the sealed test FOUP 13 was measured. The result is shown in FIG.

As a result of the test, it can be seen that the lower the internal / external differential pressure of the test mini-environment space unit 3, the lower the oxygen concentration inside the test FOUP 13 after sealing. The oxygen concentration value after 180 seconds from the start of supply is 152 ppm at 3.5 Pa, and it can be seen that the increase in oxygen concentration is suppressed compared to the above-described test at a flow rate of 120 liters. Further, the oxygen concentration at a lower differential pressure of 1.0 Pa is suppressed to 28.9 ppm after 180 seconds from the start of supply. The increase in oxygen concentration is less than one-fourth at a differential pressure of 2.5 Pa and less than one-tenth at a differential pressure of 1.0 Pa, compared to the numerical value of the test at 3.5 Pa described above. It became.

The graph of the differential pressure of 0 Pa in FIG. 17 is obtained when the fan filter unit 5 is stopped and the internal / external differential pressure of the test mini-environment space unit 3 is made zero. 110 seconds after the start of nitrogen gas supply, the oxygen concentration decreased to 4.6 ppm and maintained 9.1 ppm even after 180 seconds, and gradually increased but almost stabilized. Therefore, it was found that the minimum mini-environment internal / external differential pressure may be zero Pa.

However, in the case of an actual processing apparatus 1 operated in a semiconductor factory or the like, since the transfer robot 4 is transferring the wafer 15 inside the mini-environment space unit 3 and it is necessary to maintain the cleanliness, the fan filter unit 5 The supply of highly clean air from is necessary for this type of treatment device 1. As described above, the purge port 40 (atmosphere replacement device) of the specific embodiment shown in the drawing is in fluid (gas) communication with the outside through a gap. Therefore, when the purge port 40 (atmosphere replacement device) of the embodiment is applied to such an environment, the internal / external differential pressure of the mini-environment space unit 3 has a lower limit of 0.1 Pa, preferably a differential pressure of 1.0 Pa. From the vicinity, the upper limit is about 4 Pa. That is, when the purge port 40 of the gap fluid (gas) communication type is applied to the actual processing apparatus 1, it is possible to efficiently replace the atmosphere by the purge port 40 while maintaining a practically stable cleanliness in the processing apparatus 1. The differential pressure (internal / external differential pressure of the mini-environment space unit 3) is in this range. Desirably, the purge port 40 according to the illustrated specific example has an atmosphere replacement operation time of at most about 180 seconds or 180 seconds by operating in an environment where the differential pressure is 0.5 Pa or more and 2.5 pa or less. Thus, the oxygen concentration in the FOUP 13 of 100 ppm or less (a concentration target value that means that atmosphere substitution that can sufficiently suppress the oxidation of the wafer has been made) can be achieved.
As described above, the purge port 40 (atmosphere replacement device) according to the illustrated specific example has a limited amount of gas (high clean air, low clean air) through the gap with the external environment. There is a communication structure. In particular, the performance of the purge port 40 (atmosphere replacement device) according to the illustrated specific example depends on the state of the high cleanliness air unit 3 (for example, its positive pressure). However, it is clear that the high cleanliness air unit 3 does not constitute a component of the purge port 40 (atmosphere replacement device) according to the specific illustrated embodiment. Therefore, it should be understood that the high cleanliness air unit 3 itself does not form part of the present invention.

Next, the purge port 40 is applied to an environment in which the differential pressure inside the test mini-environment space unit 3 is maintained at a positive pressure of 2.5 Pa, and the conditions of the flow rate and the supply time of the nitrogen gas as the purging gas are changed. In this case, a test was conducted to see the time transition of the oxygen concentration in the FOUP 13 with respect to the purging operation. In this test, the flow rate of nitrogen gas was set to 120 liters per minute and 150 liters per minute, and for each flow rate, the change in oxygen concentration when the supply time was 80 seconds and 110 seconds, We decided to look at the relationship between flow rate and supply time. FIG. 18 is a graph of the results.

The total supply amount of nitrogen gas when supplying 120 liters of nitrogen gas per minute for 80 seconds is 160 liters, and the total supply amount of 110 liters when supplying nitrogen gas for 110 seconds is 220 liters. Further, the total supply amount of nitrogen gas when supplying 150 liters of nitrogen gas per minute for 80 seconds is 200 liters, and the total supply amount when supplying 110 seconds is 275 liters. When the total supply of nitrogen gas is 160 liters per minute and the flow rate of 120 liters per minute of nitrogen gas is supplied for 80 seconds, the oxygen concentration once reaches 100 ppm or less, but the target of 100 ppm or less is maintained. could not.

Moreover, the oxygen concentration when the nitrogen gas with the flow rate of 150 liters per minute, which is the largest flow rate, is supplied for 110 seconds, is temporarily reduced to 4.57 ppm, but the oxygen concentration after sealing is increased. As a result, the oxygen concentration was higher than the test result of supplying for 110 seconds at a flow rate of 120 liters per minute.

From the above results, it was proved that if nitrogen gas at a flow rate of 150 liters per minute was supplied for 80 seconds, the inside could be maintained at an oxygen concentration of 100 ppm or less even after the FOUP was sealed. The target value was achieved even when nitrogen gas at a flow rate of 120 liters per minute was supplied for 110 seconds, and the oxygen concentration was the lowest, but the total supply amount of nitrogen gas was 220 liters. Since the supply time takes 110 seconds and may affect the delay of the next process, care must be taken when determining the optimal supply conditions.

In addition, as the purge plate 41 for supplying nitrogen gas in the above test (a series of tests shown in FIGS. 16 to 18), the surface toward the FOUP opening surface is a protective cover 50, and the size is 260 mm in length and 80 mm in width. Then, a punching plate (aperture ratio 29.6%) having 1240 holes with a diameter of 2 mm on the nitrogen outflow surface of 194 mm in length and 68 mm in width in the upper part was used.

In the test shown in FIG. 17 described above, when the oxygen concentration was measured up to 180 seconds after starting the supply of nitrogen gas with the internal / external differential pressure set to 0 Pa, nitrogen was supplied from the outflow surface of the purge plate 41 at 150 liters per minute. When supplied, the supply time of nitrogen gas required to maintain the oxygen concentration 60 seconds after sealing of the test FOUP 13 at 100 ppm or less was 55 seconds, and the time for making it 10 ppm or less was 110 seconds. . From this, the differential pressure inside and outside the test mini-environment space unit 3 prevents dust from entering the carrier 16 until the test FOUP 13 is opened and the supply of nitrogen from the purge plate 41 into the carrier 16 is started. After that, it was found that the internal / external differential pressure of the test mini-environment space unit 3 may be zero. Since the volume of the test FOUP 13 is about 30 liters as in the normal FOUP 13, the nitrogen ventilation frequency (converted value) in the FOUP 13 at this time is 5 times / minute, and the nitrogen outflow rate is the center of the nitrogen outflow surface. It was 0.19 m / min at a position of 20 mm from the portion toward the inside of the carrier 16.

Next, after the supply of nitrogen gas is started, the fan filter unit 5 is stopped so that the differential pressure inside and outside the clean booth (test mini-environment space unit 3) becomes zero, and the minimum from the outflow surface of the protective cover 50 A test was conducted to determine the nitrogen supply rate. As a result, it was found that in order to reduce the oxygen concentration after 1 minute in the FOUP to 100 ppm or less, when supplying nitrogen gas at a flow rate of 48 liters per minute, 6 minutes are required until the sealing (Fig. (Omitted). If the nitrogen gas flow rate is less than this, it takes too much time to supply the nitrogen gas, and the amount of nitrogen gas consumption is large and impractical. At this time, the ventilation frequency in the FOUP by nitrogen gas is calculated as 1.6 times / min. The measurement result of the flow velocity at this time was 0.06 m / sec at a position of 20 mm from the center of the nitrogen outflow surface toward the FOUP.

In the present invention, an inert gas such as nitrogen is supplied in a laminar flow from the protective cover 50 of the purge plate 41 moved near the center of the FOUP opening surface 161, and the flow is distributed to the left and right and up and down on the back wall of the FOUP. The gas is discharged from between the periphery of the purge plate and the periphery of the FOUP opening surface 161. In the present invention, since the flow of the inert gas is required to be a laminar flow, the Reynolds number was calculated and verified. In general, it is said that when the Reynolds number exceeds 2000 to 4000 in a circular pipe fluid, the laminar flow changes to turbulent flow.

The Reynolds number can be obtained from the equation Re = UL / μρ.
Where U: Speed [m / s]
L: Distance [m], nitrogen outlet hole of purge plate 41 φ2 mm, wafer interval 10 mm
μ: Viscosity [Pa · sec], 20 ° C Nitrogen 1.8 × 10 ^-5 Pa · sec
ρ: density [kg / m ³ ], nitrogen at 20 ° C. and 1.165.
First, the nitrogen flowing out from each hole of the purge plate 41 is calculated.

The Reynolds number of the nitrogen gas flowing out from one of the 1240 φ2 mm holes opened in the protective cover 50 is Re = 61 when supplying 150 liters per minute from the purge plate 41 into the carrier 16. Re = 163 was calculated when supplying 400 liters. From this result, it can be said that the laminar flow is sufficiently maintained at any flow rate. At this time, the flow velocity at a position 20 mm from the nitrogen gas outflow surface of the protective cover 50 was 0.50 m / sec.

Next, the Reynolds number of the nitrogen gas flowing into the FOUP is calculated. The distance L between the wafers stored in the FOUP is L = 10 mm. When 400 liters of nitrogen gas is supplied here, the Reynolds number is as small as Re = 24, and it can be said that the flow is laminar. In addition, the ventilation frequency at this time is 13.3 times / minute. However, when the supply amount of nitrogen gas exceeds 400 liters per minute, the replacement speed does not decrease compared to the flow rate, and the total outflow amount of nitrogen gas increases. Inefficient and not preferable.

For the reasons described above, the wind speed of the inert gas (nitrogen) at a position 20 mm from the rectifying plate 50 (the gas outflow plate of the purge plate) is suitably between 0.05 m / sec and 0.5 m / sec. Preferably, it is 0.1 m / sec to 0.3 m / sec. In terms of the number of ventilations, 1.4 times / minute to 13.3 times / minute is appropriate, and preferably 2.6 times / minute to 7 times / minute. The physical numbers described here are applied on the assumption that the storage container FOUP 13 is a FOUP for storing 25 300 mm wafers with a capacity of 30 liters.

In the tests so far, it was proved by the above example that the atmosphere in the FOUP could be replaced with a predetermined inert gas concentration within a predetermined time. However, even if the atmosphere in the folding FOUP can be replaced, it does not make sense to cause dust to float inside the FOUP and deposit on the wafer surface. Therefore, in the next test, the wafer in the test FOUP 13 when the pressure difference between the inside and outside of the test mini-environment space unit 3 is 2.5 Pa and the flow rate of 120, 150 and 200 liters of nitrogen gas per minute is supplied for 110 seconds. The number of dust on the surface was measured.

The dust measurement test was performed by the PWP (Particles on Wafer per Pass) method. Specifically, five measurement wafers that had been previously measured for the number of dust adhering to the surface were placed on the first, seventh, thirteenth, nineteenth, and twenty-fifth shelf in the test FOUP 13, respectively. Thereafter, the operation of opening the test FOUP 13 with the purge port 40, replacing the atmosphere, and sealing is taken as one step, and this is repeated five times. After that, by measuring the number of dust adhering to the surface of the measuring wafer, an increase in the number of dust having a diameter of 0.12 micrometers or more adhering per measuring wafer in one step of the atmosphere replacement operation is obtained. This is a test method.

As a result, the average number of dust per wafer was 18.8 at the initial stage, and nitrogen gas was 18.3 per 120 liters per minute (ventilation rate 4 times / min, flow rate 0.15 m / sec). 19.1 liters at 150 liters per minute (5 ventilations / minute, flow rate 0.19 m / s), 200 liters per minute (6.7 ventilations / minute, flow rate 0.25 m / s) 22. There were six. From this test, the increase or decrease in the number of dust is within the measurement error range up to 150 liters per minute, but when the flow rate exceeds 200 liters per minute, the increase in the number of dusts begins. It was found that about 0.3 m / second or less is preferable. The cause of the increase in dust is generally that there is a lot of dust adhering to the back surface of the wafer, so it is considered that the dust on the back surface was blown off by a strong nitrogen stream and deposited on the wafer surface.

<Purging performance>
The purging performance of a specific example supported by the above test results is summarized. According to this specific embodiment, the air in a 30 liter container represented by FOUP can be replaced in a short time of usually 80 seconds, at most 180 seconds or less, and the amount of inert gas used can be reduced. The oxygen concentration after sealing could be kept at 10 ppm or less, at least 100 ppm or less. In the case where the inert gas ejection suppressing means is provided in the purge plate, the gas exiting the outflow surface of the purge plate can be maintained in a laminar flow, and the atmosphere can be replaced with a small amount of inert gas. In addition, a purge plate smaller than the FOUP opening surface is positioned at the center of the FOUP opening surface to allow the inert gas to flow out, so that the FOUP air can be discharged outside the periphery of the purge plate, which is also a small amount of inert gas. Contributes to atmosphere replacement with gas. Further, by providing the flange panel 65 and the shield cover 67 with a labyrinth structure, air intrusion into the FOUP could be minimized. Moreover, there was no adhesion of dust to the objects to be contained. The principle of this embodiment can be applied even if the volume of the container changes.

As described above, when the cover 17 and the carrier 16 are separated through the description of the above embodiment, the load using the moving mechanism that separates the carrier 16 by moving the carrier 16 backward with respect to the cover 17 while the cover 17 is stationary. An apparatus (purge port 40) and method for adding an atmosphere replacement function with an inert gas at a port have been disclosed. In addition, an atmosphere replacement device (purge port 40) and method compatible with this existing load port have been disclosed. However, the present invention is not limited to the above embodiments. For example, those skilled in the art will appreciate variations in the moving mechanism used in the purge port. For example, a mechanism that separates the carrier 16 and the cover 17 by moving only one of the FIMS doors 12 integrated with the cover 17 away from the carrier 16 in the horizontal direction, or both the carrier 16 and the cover 17 in the opposite horizontal direction. The atmosphere replacement device and method of the present invention can also be applied to a load port using a mechanism for moving to the position, and it is possible to achieve the same effects as in this embodiment. Alternatively, in a simple configuration, a mechanism for separating the carrier 16 and the cover 17 in the horizontal direction, and a purge plate 41 having a surface through which inert gas flows out into the carrier 16 at the center between the carrier 16 and the cover 17 are provided. If it is provided with the mechanism to insert and provided the ventilation frequency of the above-mentioned range, the atmosphere substitution apparatus of this invention can be comprised, and the method of this invention can be implemented using such an apparatus. As will be apparent to those skilled in the art, the purge port of the specific embodiment described in detail can be constructed independently of the load port and can be modified to be used independently within the scope of the present invention. It's just a trivial variant.

Further, through the description of the present embodiment, the silicon wafer FOUP defined by the SEMI standard and the load port adapted to the FOUP are disclosed, but the present invention is not limited to this, and the liquid crystal The present invention can also be applied to substrates that require fine processing, such as display substrates and solar cell panel substrates. In addition, a container that contains a substrate to be processed and is sealed from an external atmosphere, a transfer device that places or transfers the container, and a process that transfers a workpiece from the container and performs a predetermined process. As long as it is an apparatus, the atmosphere replacement apparatus and method of the present invention can be effectively applied to this kind of container of any kind of processing apparatus.

40: Purge port (atmosphere replacement device)
41: Purge plate 49: Ejection suppression element 50: Rectifying plate (outflow surface)
51-53: Purge plate lifting mechanism (purge plate drive mechanism)
13: FOUP (FOUP type container)
161: Open surface 15: Wafer (substrate)
2: Load port 3: Mini-environment space unit 4: Transfer robot 12: FIMS door (door)
43 & 56: Door drive mechanism 43: Horizontal door drive mechanism 56: Vertical door drive mechanism 45: Inner wall 44: Opening 121: High

cleanliness air passages

67a, 67b: Labyrinth shield cover 68: Auxiliary nozzle

Claims

In the atmosphere replacement device (40) for purging the FOUP type container (13) with a purge gas,
A non-nozzle purge plate (41) designed to flow laminar purge gas from the outflow surface (50);
A purge plate drive mechanism (51, 52, 53) for moving the purge plate (41) between a standby position and an operating position;
During the purge period, the purge plate (41) is in the operating position, facing the open surface (161) of the container (13), and laminar flow toward the inside of the open surface (161). Purging the vessel (13) by flowing a purge gas;
An atmosphere replacement device comprising:
The atmosphere replacement device according to claim 1, wherein in the operating position, the purge plate (41) is arranged such that a laminar purge gas flows out toward the center of the open surface (161).
The atmosphere replacement device according to claim 1, wherein the FOUP type container (13) is a container for storing a substrate (15).
The atmosphere replacement device according to claim 2, wherein the substrate (15) is a wafer (15).
The atmosphere replacement device according to claim 1, which is compatible with the load port (2).
The atmosphere replacement device according to claim 1, wherein the purge gas is nitrogen gas.
The atmosphere replacement device, wherein the purge plate (41) has an area smaller than the open surface (161) of the container (13).
The atmosphere replacement device according to claim 1, wherein the purge plate (41) includes an ejection suppression element (49) configured to suppress an ejection output of the purge gas.
The atmosphere replacement device according to claim 8, wherein the ejection suppressing element (49) is made of a porous material.
An openable and closable door (12) that enables access to the FOUP type container (13) by the transfer robot (4) when opened;
The atmosphere replacement device according to claim 1, further comprising a door drive mechanism (60-63, 56) for moving the door (12) in the X direction and the Y direction.
The atmosphere replacement device according to claim 10, wherein the X direction is a horizontal direction and the Y direction is a vertical direction.
An openable and closable door (12) that enables access to the FOUP type container (13) by the transfer robot (4) when opened;
The high cleanliness air passage (121) which passes the crevice formed between the inner wall (45) arranged at the perimeter of the door (12), and the door (12) and the inner wall (45). 2. The atmosphere replacement device according to 1.
An inner wall shield cover (67a, 67b) having a labyrinth structure provided on the inner wall (45);
A labyrinth structure door shield cover (67a, 67b) provided on the door;
The atmosphere replacement device according to claim 12, comprising the non-contact sealing of the gap by the inner wall shield cover (67a, 67b) and the door shield cover (67a, 67b).
An inner wall shield cover (67a, 67b) having a labyrinth structure provided on the inner wall (45);
A labyrinth structure door shield cover (67a, 67b) provided on the door;
A door drive mechanism (60-63) for moving the door in a horizontal direction;
Depending on the horizontal position of the door, the degree of sealing between the inner wall shield cover (67a, 67b) and the door seal, and therefore the gap can be adjusted,
The atmosphere substitution device according to claim 12 provided.
The atmosphere replacement device according to claim 1, which is arranged adjacent to the mini-environment space unit (3).
The atmosphere replacement device according to claim 15, which is configured so that high cleanliness air from the mini-environment space unit (3) communicates through a gap.
An opening (44) into which the FOUP type container (13) is docked;
An inner wall (45) defining the opening (44);
The gap is formed between the inner wall (45) and the periphery of the door (12);
An auxiliary nozzle (68) provided above the opening (44) and for discharging the purge gas toward the container (13);
The atmosphere substitution device according to claim 16 provided.
The purge gas amount per minute flowing out of the purge plate (41) during the purge period ranges from 1.4 to 13.3 times the volume of the vessel (13). Atmosphere replacement equipment.
The velocity of the purge gas flowing out of the purge plate (41) ranges from 0.05 meter / second to 0.5 meter / second at a position 20 mm forward from the purge plate. Atmosphere replacement device.
The atmosphere replacement device, wherein the area of the purge plate (41) ranges from 10% to 60% of the area of the open surface (161) of the container (13).