JP5503389B2 - Storage system and storage method - Google Patents

Description

  The present invention relates to storage objects (raw materials, parts, products, etc.) such as silicon wafers used as substrates for integrated circuits, pattern masks for integrated circuits, parts of liquid crystal display devices, etc. It is related with the storage system and the storage method for hold | maintaining in the state which avoided the contact with. More specifically, the present invention can store a storage object in a sealed manner, and allows gas movement from the inside to the outside and gas movement from the outside to the inside based on a pressure difference between inside and outside. The present invention relates to a storage system and a storage method including a storage container provided with a port and an inert gas supply means for supplying an inert gas to the storage container.

  As prior art document information related to this type of storage system, there is Patent Document 1 shown below. The storage system described in Patent Document 1 includes a FOUP (storage container) capable of sealingly storing a plurality of silicon wafers and having an inlet and a discharge port (gas control port) for purge gas, Each storage room is provided with a purge valve connected to an inert gas supply path for purging the inside of the FOUP. If the storage container is placed at the correct position in the storage chamber, the inlet of the storage container and the purge valve are connected in communication, and the inside of the storage container is purged by the inert gas introduced through the purge valve. That is, inconvenient oxygen gas or the like in the storage container is replaced with an inactive gas with little inconvenience.

  The purge valve includes a housing fixed to the floor surface of each storage chamber and an actuator provided above the housing. The actuator is provided so as to be movable up and down so as to function as an on-off valve that opens and closes a gas flow path formed inside the purge valve. The actuator is normally held by a spring in an upper closed position that does not allow the passage of gas, and is pushed down to a lower open position by a part of the lower surface of the storage container placed in the storage chamber, so that the inert gas Installation is performed. By using the purge valve having such a configuration, an automatic purge mechanism that does not require consumption of electric power or the like for switching the gas flow path is realized.

JP 2005-167168 A (paragraphs 0017-18, 0021-22, FIG. 1-3)

  However, in the storage system described in Patent Document 1, the moisture contained in the introduced inert gas has an adverse effect on the silicon wafer because the existing air is expelled into the FOUP by an inert gas such as nitrogen. There is a risk that the introduced inert gas causes dust in the FOUP to float and adhere to the silicon wafer.

  Furthermore, an expensive storage chamber having a high-accuracy purge valve that is automatically connected to the inlet of the storage container by storing the storage container is required. In addition, after the purge in the FOUP is completed, the inert gas with the same large flow rate as that at the beginning of the purge is continuously supplied. Since a large amount of inert gas is required, the running cost is high and the resources are wasted. There was also a problem such as easy connection.

An object of the present invention is to provide a storage system and a storage method capable of storing a storage object such as a silicon wafer under better conditions in view of the problems given by the storage system according to the prior art exemplified above.
Another object of the present invention is to provide a storage system and a storage method capable of reducing the consumption of inert gas in view of the problems given by the storage system according to the prior art exemplified above.

The first characteristic configuration of the storage system according to the present invention is:
A storage container having a gas control port that can store an object to be stored in a sealed manner and allows gas movement from the inside to the outside and gas movement from the outside to the inside based on a pressure difference between the inside and outside,
A sealed vacuum chamber for storing the storage container in a removable manner;
An exhaust path connecting the vacuum chamber and a vacuum decompressor;
An inert gas supply path for opening and closing the vacuum chamber and an inert gas supply means;
A vacuum storage mode in which the inside of the vacuum chamber is maintained at a predetermined vacuum level by the vacuum decompression device in a state where the inert gas supply path is closed, and the vacuum chamber and the storage container at the time of delivery of the selected storage container And an unloading preparation mode for switching the inert gas supply path corresponding to fill with the inert gas to an open state.

  In the storage system according to the first characteristic configuration of the present invention, the vacuum chamber is basically kept in a vacuum state until a delivery command is issued for the corresponding storage object, and the delivery command is issued. For the first time, an inert gas in an amount that fills the vacuum chamber and the internal storage container is supplied only to the applicable vacuum chamber, so the storage object such as a silicon wafer is adversely affected by moisture contained in the inert gas. The amount of inert gas consumed can be greatly reduced. In the vacuum storage mode, air in the storage container is exhausted through the gas control port, and in the delivery preparation mode, inert gas is injected into the storage container through the gas control port. There is no need to use expensive storage rooms. In addition, when supplying inert gas such as nitrogen to the vacuum chamber of the storage container for which a delivery instruction has been issued, the minimum amount required for the vacuum chamber and storage container in a vacuum state is not expelled from the air in the storage container. Since the inert gas may be sent at a small flow rate, the possibility that the introduced inert gas floats up dust in the storage container and adheres to a storage object such as a silicon wafer is reduced.

  Another feature of the present invention is that the plurality of vacuum chambers are connected to one vacuum decompression device via individual on-off valves, and the vacuum chambers are decompressed simultaneously in the vacuum storage mode. Is limited to a certain value or less.

  With this configuration, a large number of storage containers and storage objects stored in the same storage container can be stored at one time, and the number of vacuum chambers to be depressurized at the same time is limited to a certain value or less. Regardless of the number of vacuum chambers, each vacuum chamber can be quickly brought into a desired vacuum state even if a vacuum pump having a relatively small capacity is employed as a vacuum decompression device.

  According to another characteristic configuration of the present invention, a vacuum degree determination unit that determines the degree of vacuum in the vacuum chamber is provided. In the vacuum storage mode, the vacuum pressure reducing device is based on a determination result by the vacuum degree determination unit. The point is that pressure reduction is performed.

  Even if the degree of vacuum in the vacuum chamber and the storage container decreases due to moisture generated from a storage object such as a silicon wafer, a small amount of outgas, or due to insufficient air density of the vacuum chamber, this configuration The decrease in the degree of vacuum is detected by the degree-of-vacuum determination means, and the degree of vacuum in the vacuum chamber and the storage container is always maintained at a constant level by performing the pressure reduction by the vacuum pressure reducing device.

  Another feature of the present invention is that a check valve for restricting the flow of gas from the vacuum pressure reducing device side toward each vacuum chamber is provided.

  With this configuration, even if one exhaust path is opened without noticing that an abnormality has occurred in the capacity of the vacuum decompression device, the possibility that air or the like flows back into the vacuum chamber is suppressed.

  Another feature of the present invention is that in the vacuum storage mode, the inert gas supply path of the vacuum chamber, which has been decompressed to the predetermined vacuum level by the vacuum decompressor, is continuously decompressed by the vacuum decompressor. However, the gas remaining in the vacuum chamber and the storage container is purged with an inert gas.

In a state where the pressure is simply reduced to a vacuum level by a vacuum pressure reducing device, a slight amount of gas component remaining in the vacuum chamber or storage container is close to the air component and contains about 20% oxygen. If so, most of the residual gas is replaced by an inert gas such as nitrogen, so that a storage object such as a silicon wafer can be stored more safely.
Also, with this configuration, an air flow is created in the storage container by introducing fresh inert gas into the storage container whose pressure has been reduced once, so outgas generated from the silicon wafer and FOUP by this air flow Also, the effect that dust is expelled from the storage container via the gas control port can be obtained.

  According to another feature of the present invention, when the determination result by the degree-of-vacuum determination means does not fall below a predetermined value regardless of the pressure reduction by the vacuum pressure reduction device, a warning is issued and at the same time, the vacuum chamber, the storage container, In other words, the corresponding inert gas supply path is switched to an open state so as to be filled with the inert gas.

  If the determination result by the degree-of-vacuum determination means does not fall below a predetermined value regardless of the pressure reduction by the vacuum pressure reduction device, the airtightness of the vacuum chamber is low, or the degree of vacuum determination means is likely to be broken. Therefore, as in this configuration, the corresponding inert gas supply path is switched to the open state, and the vacuum chamber and the storage container are filled with the inert gas, so that the storage object is stored by the oxygen contained in the air entering the vacuum chamber. Can be minimized as much as possible. Further, based on the automatically issued warning, it is possible to prompt the operator to check the air density of the vacuum chamber and the degree of vacuum determination means.

  A characteristic configuration of the storage method according to the present invention is that a storage system according to any one of claims 1 to 5 is used.

  With the storage method according to this configuration, the vacuum chamber is basically kept in a vacuum state until a delivery command is issued for the object to be stored, and the vacuum is only applied to the corresponding vacuum chamber for the first time when the delivery command is issued. The amount of inert gas that fills the chamber and the internal storage container is supplied, so the chance that the storage object will be adversely affected by moisture contained in the inert gas can be significantly reduced, and the consumption of inert gas Can be greatly reduced. In addition, when supplying inert gas to the vacuum chamber of the storage container for which a delivery instruction has been issued, it is sufficient to send the minimum amount of inert gas to the vacuum chamber and storage container in a vacuum state at a low flow rate. The possibility that the active gas floats up dust in the storage container and adheres to the storage object is reduced.

It is a schematic block diagram which shows the storage system which concerns on this invention.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated, referring drawings.
(Overall configuration of storage system)
The storage system according to the present invention is intended to store various electronic components in a state avoiding contact with dust, gas (such as O ₂ ) and moisture which are inconvenient for the components. Here, a case where the silicon wafer 2 which is a semiconductor material is handled as an electronic component will be described as an example, but the present invention can also be applied to a reticle, a mask or the like used in an exposure apparatus.

The storage system according to the present invention is installed in a common storage area composed of a clean room adjacent to a process apparatus (not shown) for manufacturing and processing the silicon wafer 2 and is independent of each other as shown in FIG. A number of vacuum chambers C (C ₁ , C ₂ ... C _n ) are provided. Basically, the silicon wafer 2 is handled in a state where it is stored in a plurality of FOUPs 4 (an example of storage containers) that can store a large number of silicon wafers 2 in a sealed state.
The FOUP 4 is designed on the assumption that it is used in the vicinity of the atmospheric pressure, and since the pressure inside the FOUP 4 cannot be reduced directly by a pressure reducing device, the pressure is reduced through the vacuum chamber C in which the FOUP 4 is stored.
Here, a large number of vacuum chambers C are used at the same time, but it is also possible to carry out the configuration with a single vacuum chamber C.

(Structure of FOUP)
The FOUP 4 is generally composed of a rectangular parallelepiped housing, and generally has an open / close lid (not shown) capable of closing the inside in an airtight manner. The opening / closing lid is attached / detached by a dedicated opener (not shown) or manually. The bottom surface of the FOUP 4 has a discharge port 4a that allows gas movement from the inside to the outside of the FOUP 4 based on a pressure difference between inside and outside, and an introduction that allows gas movement from the outside to the inside based on a pressure difference between inside and outside. Port 4b is provided. A check valve (not shown) that allows only discharge of gas exceeding a predetermined pressure is interposed in the discharge port 4a, and a check valve (not shown) that allows only gas inflow exceeding a predetermined pressure is interposed in the introduction port 4b. Has been. The discharge port 4a and the introduction port 4b cooperate to constitute a gas control port. A breathing filter (not shown) that eliminates the pressure difference between the inside and outside of the FOUP 4 while preventing dust from entering the FOUP 4 may be disposed inside the check valves of the discharge port 4a and the introduction port 4b. Or you may implement in the form of the gas control port which abbreviate | omitted the check valve and provided only with the breathing filter.

(Structure of vacuum chamber)
One side surface or upper surface of each vacuum chamber C (C ₁ , C ₂ ... C _n ) is closed so as to be freely opened and closed by a lid member CL capable of closing the inside in a sealed manner. In a state where the cover member CL is opened, one or a plurality of FOUPs 4 can be taken in and out of the vacuum chamber C manually or by a robot hand (not shown).
Each vacuum chamber C is connected in parallel with vacuum decompression devices P and 5 described later, and at the same time, connected in parallel with an inert gas supply means 7 such as a nitrogen gas cylinder.

Each vacuum chamber C vacuum pressure reducing device P, 5 vacuum path is connected to the _{Rd (Rd 1, Rd 2 ···} Rd n) off valves Va (Va for the intermediate in the gas emissions (an example of an exhaust passage) _1, Va ₂ ··· Va _n) is interposed. Similarly, inert gas supply path _{Rp (Rp 1, Rp 2 ···} Rp n) middle also for gas supply on-off valve _{Vb (Vb 1, Vb 2 ···} Vb n) is interposed . These on-off valves Va and Vb can be opened and closed by signals from a control unit 10 described later.
Each vacuum chamber C is provided with a pressure sensor PS1 (PS1, PS1,... PSn) (an example of a degree of vacuum determination means) that detects the pressure (degree of vacuum) in the chamber.

(Configuration of vacuum decompression device)
The vacuum decompression device for decompressing the inside of the vacuum chamber C is connected to the decompression path Rd (Rd ₁ , Rd ₂ ... Rd _n ) of each vacuum chamber C via the main decompression path RdT (an example of an exhaust path). And the vacuum pump P that keeps the inside of the auxiliary vacuum chamber 5 at a predetermined degree of vacuum.
The auxiliary vacuum chamber 5 is also provided with a pressure sensor PSt that detects the pressure (degree of vacuum) in the chamber. A check valve CV having a high reaction speed is interposed between the auxiliary vacuum chamber 5 and the main decompression path RdT as a means for preventing the inflow of gas from the auxiliary vacuum chamber 5 toward each vacuum chamber C.
In a normal operation state of the storage system, when one vacuum chamber C in which the FOUP 4 is housed is communicated with the auxiliary vacuum chamber 5 by opening the corresponding pressure reducing on-off valve Va, the inside of the vacuum chamber C The gas is exhausted, and at the same time, the gas inside the FOUP 4 is also exhausted through the exhaust port 4a due to the pressure difference between the inside and outside, so that both the vacuum chamber C and the FOUP 4 reach a predetermined degree of vacuum.

(Configuration of inert gas supply means)
The inert gas supply means 7 is provided to supply an inert gas to the vacuum chamber C selected as necessary, and the inert gas supply path Rp of each vacuum chamber C via the main supply path RpT. A nitrogen gas cylinder connected to (Rp ₁ , Rp ₂ ... Rp _n ) can be used.

  In the normal operation state of the storage system, the inert gas supply means 7 is opened by opening the corresponding inert gas supply opening / closing valve Vb in one vacuum chamber C in which the FOUP 4 that needs to be prepared for delivery is stored. Inert gas is introduced into the vacuum chamber C through the on-off valve Vb. At the same time, the inert gas introduced into the vacuum chamber C is introduced into the FOUP 4 via the introduction port 4b due to the pressure difference between the inside and outside. Are both introduced, so that both the vacuum chamber C and the FOUP 4 are filled with an inert gas at a predetermined pressure (generally the same as the pressure in the storage area where the storage system is present).

(Configuration of control unit)
The control unit 10 that manages almost the entire storage system basically keeps all the inert gas supply paths Rp closed, and vacuums and decompresses the insides of all the vacuum chambers C in which the FOUPs 4 are stored. Maintain a vacuum storage system that maintains a predetermined vacuum level (vacuum storage mode) by P and 5 and inactivate FOUP 4 only when the selected FOUP 4 is released from the storage system (output preparation mode). Control is performed so that only the inert gas supply path Rp of the corresponding vacuum chamber C is opened to be filled with gas.

  Therefore, an input device 20 for manually setting and inputting any one of the vacuum storage mode, the shipping preparation mode, and the suspension mode for each vacuum chamber C is disposed in a part of the storage system. The pause mode is set for the vacuum chamber C that does not contain the FOUP 4, and the vacuum chamber C set to the pause mode is held in a closed state in both the decompression path Rd and the supply path Rp.

  As shown in FIG. 1, the control unit 10 includes a mode determination unit 12, a pressure determination unit 13, an operation control unit 14, a valve opening / closing operation unit 15, and the like. The mode determination unit 12 determines the mode for each vacuum chamber C set and input by the input device 20. The pressure determination unit 13 determines the pressure (degree of vacuum) in each vacuum chamber C detected by the pressure sensor PS (PS1, PS2,... PSn) by comparing it with a reference value. The operation control unit 14 switches the driving state of the vacuum pump P on and off according to the pressure in the auxiliary vacuum chamber 5 detected by the pressure sensor PSt. Based on the determination result of the mode determination unit 12 and the pressure (vacuum degree) in each vacuum chamber C, the valve opening / closing operation unit 15 is configured to open / close valves Va (Va1, Va2,... Van) and inert gas in the decompression path Rd. The on-off valve Vb (Vb1, Vb2,... Vbn) on the supply path Rp is opened / closed.

  As a means for limiting the number of vacuum chambers C simultaneously decompressed by the vacuum decompressors P, 5 to the control unit 10, the control unit 10 includes a plurality of on-off valves Va (Va1, Va2,... An interlock (not shown) is provided to prevent Van) from being simultaneously opened. However, depending on the capacity of the vacuum pump P and the auxiliary vacuum chamber 5 with respect to the scale of the vacuum chamber C, the upper limit number of vacuum chambers C that can be depressurized simultaneously may be set to 2 or more. If the opening / closing valves Va of the plurality of vacuum chambers C having different degrees of vacuum are opened at the same time, gas may flow from the vacuum chamber C having a low degree of vacuum to the vacuum chamber C having a high degree of vacuum. Therefore, in the case of carrying out a configuration in which a plurality of vacuum chambers C are simultaneously decompressed, in order to prevent such gas movement, on the downstream side (vacuum pump P side) of the open / close valve Va of each vacuum chamber C, etc. It is preferable to provide a check valve for restricting gas from entering the vacuum chamber C from the main decompression path RdT side.

(Operation method of storage system)
During the initial operation of the storage system, all the open / close valves Va (Va1, Va2... Van) in the decompression path Rd and all the open / close valves Vb (Vb1, Vb2... Vbn) in the inert gas supply path Rp are closed. , the internal pressure (vacuum) of the auxiliary vacuum chamber 5 drives the vacuum pump P to a predetermined lower reference value 5R _L. Thereafter, during operation of the storage system, the operation control unit 14 of the control unit 10 based on the determination result of the pressure determination unit 13, the internal pressure of the auxiliary vacuum chamber 5 (vacuum) is a predetermined upper reference value 5R _H If so, the vacuum pump P is driven. As a result, the inside of the auxiliary vacuum chamber 5 is always maintained within the range of from lower reference value 5R _L to the upper reference value 5R _H.

Next, when the operator sets all the vacuum chambers C in which the FOUP 4 is stored by the input device 20 to the vacuum storage mode, the valve opening / closing operation unit 15 of the control unit 10 selects only one of the set vacuum chambers C. Then, only the open / close valve Va corresponding to the vacuum chamber C is switched to the open state. When the internal pressure of the selected vacuum chamber C (vacuum) becomes a predetermined lower reference value CR _L, subsequently, to select the second vacuum chamber C, switched to only open close valve Va corresponding similarly in procedure of all of the vacuum chamber C in accommodating FOUP4 it is reduced below the reference value CR _L. Incidentally, the to apply the operation to reduce the pressure in the lower reference value CR _L from which the vacuum chamber C above, advance to create a LUT specifying the priority of the vacuum chamber C conveniently in advance, the control unit 10 is this The processing order can be determined based on the LUT.

(Vacuum storage mode)
Thereafter, during operation of the storage system has determined that any internal pressure in the vacuum chamber C in accommodating the pressure determination unit 13 is FOUP 4 (degree of vacuum) reaches a predetermined upper reference value CR _H, valve operation by part 15 opens the opening and closing valve Va corresponding return the internal pressure of the vacuum chamber C a (vacuum) to the lower reference value CR _L. As a result, the interior of all the vacuum chamber C is always maintained in the range from substantially lower reference value CR _L to the upper reference value CR _H.

(Outgoing preparation mode)
When the operator sets a certain vacuum chamber C as the delivery preparation mode by the input device 20, the corresponding on-off valve Va is switched to the open state regardless of the internal pressure (vacuum degree) of the vacuum chamber C. When the vacuum chamber C by switching to the open state of the opening and closing valve Va is reduced below the reference value CR _L, closed immediately off valves Va, subsequently, opens the opening and closing valve Vb to the appropriate inert gas supply path Rp As a result, an inert gas is introduced into the corresponding vacuum chamber C and FOUP 4. FIG. 1 shows a state where the third vacuum chamber C3 is set to the delivery preparation mode.

  For each vacuum chamber C, a pressure gauge suitable for determining the pressure near atmospheric pressure is provided separately from the pressure sensor PS, and the determination result of the pressure gauge is stored in the storage system. The on-off valve Vb may be closed when a pressure value substantially equal to the atmospheric pressure in the area is shown. Subsequently, if the lid member CL of the corresponding vacuum chamber C is opened, the FOUP 4 filled with the inert gas can be taken out smoothly.

(Flow when sealing is poor)
Incidentally, for the vacuum chamber C which is set in a vacuum storage mode, if the determination result by the pressure determination unit 13 irrespective of the reduced pressure by the aspirator P, 5 do not reach the lower reference value CR _L is as an emergency measure, The on-off valve Va of the corresponding decompression path Rd is closed to issue a warning such as “Need to check the degree of sealing” and at the same time, the corresponding inert gas supply path to fill the vacuum chamber C and FOUP 4 with the inert gas. The open / close valve Vb of Rp is switched to the open state.

  Table 1 shows the results of an experiment comparing how the atmosphere to which the object to be stored is exposed differs between the conventional N2 purge storage system and the vacuum storage system according to the present invention.

In the conventional N ₂ purge storage shown on the left side of the table, the internal air was purged by injecting N ₂ gas into the FOUP 4 from the introduction port 4b at a flow rate of 10 L / min without using a vacuum chamber. On the other hand, in the vacuum storage according to the present invention described on the right side of the table, the vacuum storage was performed by using the FOUP 4 housed in the vacuum chamber C and depressurizing by the method described in the above embodiment.

As shown in Table 1, the exposure atmosphere 5 minutes after the start of the N ₂ purge by the conventional storage system had an oxygen concentration of 4.15% and a humidity of 14.5%, whereas the vacuum of the present invention. The exposure atmosphere 5 minutes after the start of depressurization by storage resulted in an oxygen concentration of 0.074% and a humidity of 0.8%. In the vacuum storage system according to the present invention, it is very important for storage objects such as silicon wafer 2 It can be seen that an advantageous atmosphere can be obtained.
N The _purge or after 10 minutes from the start of evacuation, in accordance with N ₂ purge conventional storage system, the oxygen concentration of 0.732%, but the humidity is more clean atmosphere 8.3% have been obtained, the It can be seen that the results of the oxygen storage system according to the invention having an oxygen concentration of 0.074% and a humidity of 0.8% are not yet achieved.

[Another embodiment]
<1> The auxiliary vacuum chamber 5 may be omitted, and the decompression path Rd of each vacuum chamber C may be directly connected to the suction port of the vacuum pump P.

<2> In the vacuum storage mode, the pressure is not reduced by the vacuum pressure reduction devices P and 5 based on the determination result by the vacuum degree determination means provided in the vacuum chamber C, but is not related to the measured value of the pressure in the vacuum chamber C. In addition, it is also possible to implement with a configuration in which the depressurization by the vacuum depressurization devices P and 5 is performed every time a predetermined period set in advance.

<3> In the vacuum storage mode, the inert gas supply path Rp of the vacuum chamber C decompressed to a predetermined vacuum level by the vacuum decompressors P and 5 is opened while continuing the decompression by the vacuum decompressors P and 5. Thus, it is also possible to carry out a configuration in which the gas remaining in the vacuum chamber C and the storage container 4 is purged with an inert gas (residual gas purge) while maintaining a certain degree of vacuum. Further, the residual gas purge may be performed every time the reopening-off valve Va to return the internal pressure (vacuum) in the lower reference value CR _L in any of the vacuum chamber C. Alternatively, regardless of the internal pressure (degree of vacuum) of the vacuum chamber C, the residual gas purge may be performed repeatedly at regular intervals.

<4> are described in the above embodiment, and omit the step of reducing the pressure by switching to once open the on-off valve Va of the vacuum chamber C which is set in the unloading preparation mode to a lower reference value CR _L, corresponds immediately You may implement with the form which introduce | transduces an inert gas into the applicable vacuum chamber C and FOUP4 by opening the on-off valve Vb of the inert gas supply path | route Rp. However, the opening and closing valve Va of the vacuum chamber C which is set in the unloading preparation mode, when in the open as the operation of a vacuum storage mode in, wait for closing of the opening and closing valve Va to below the reference value CR _L is recovered, After the recovery, the on-off valve Va may be closed and the on-off valve Vb of the inert gas supply path Rp may be opened.

<5> As a gas control port provided in the FOUP 4, instead of providing the discharge port 4a and the introduction port 4b, the gas control port opens to the inside or outside based on the pressure difference between the inside and the outside. The structure provided with the valve hold | maintained may be sufficient.

  A storage container having a gas control port that can store an object to be stored in a hermetically sealed state and allows a gas movement from the inside to the outside and a gas movement from the outside to the inside based on a pressure difference between the inside and outside, and the storage A storage system and a storage method provided with an inert gas supply means for supplying an inert gas to the container can be used as a technique for improving.

2 Silicon wafer 4 FOUP (storage container)
4a discharge port 4b introduction port 5 auxiliary vacuum chamber (vacuum decompression device)
7 Inert gas supply means 10 Control unit 12 Mode determination unit (control unit: vacuum storage mode / ship preparation mode)
13 Pressure determination unit (control unit)
14 Operation control unit (control unit)
15 Valve opening / closing operation unit (control unit)
20 Input device C Vacuum chamber (C ₁ , C ₂ ... C _n )
CV check valve P vacuum pump (vacuum decompression device)
PS pressure sensor (PS1, PS2, ... PSn, vacuum degree determination means)
Rd decompression path (Rd1, Rd2 ... Rdn, exhaust path)
Rp inert gas supply path (Rp1, Rp2, ... Rpn)
Va Gas on / off valve (Va1, Va2 ... Van)
Vb Gas supply on / off valve (Vb1, Vb2 ... Vbn)

Claims (7)

A storage container having a gas control port that can store an object to be stored in a sealed manner and allows gas movement from the inside to the outside and gas movement from the outside to the inside based on a pressure difference between the inside and outside,
A sealed vacuum chamber for storing the storage container in a removable manner;
An exhaust path connecting the vacuum chamber and a vacuum decompressor;
An inert gas supply path for opening and closing the vacuum chamber and an inert gas supply means;
A vacuum storage mode in which the inside of the vacuum chamber is maintained at a predetermined vacuum level by the vacuum decompression device in a state where the inert gas supply path is closed, and the vacuum chamber and the storage container at the time of delivery of the selected storage container And a storage preparation mode for switching the corresponding inert gas supply path to an open state so as to be filled with the inert gas.   A plurality of the vacuum chambers are connected to one vacuum decompression device via individual on-off valves, and the number of the vacuum chambers to be decompressed simultaneously in the vacuum storage mode is limited to a certain value or less. The storage system according to claim 1.   The vacuum degree determination means for determining the degree of vacuum in the vacuum chamber is provided, and in the vacuum storage mode, pressure reduction by the vacuum pressure reducing device is performed based on a determination result by the vacuum degree determination means. Or the storage system according to 2.   The storage system according to any one of claims 1 to 3, further comprising a check valve that regulates a gas flow from the vacuum decompression device side toward each vacuum chamber.   In the vacuum storage mode, by opening the inert gas supply path of the vacuum chamber that has been decompressed to the predetermined vacuum level by the vacuum decompression device while continuing decompression by the vacuum decompression device, the vacuum chamber The storage system according to any one of claims 1 to 4, wherein the gas remaining in the storage container is purged with an inert gas.   If the determination result by the degree-of-vacuum determination means does not fall below a predetermined value regardless of the pressure reduction by the vacuum pressure reducing device, a warning is issued and at the same time, the vacuum chamber and the storage container are applicable to be filled with an inert gas. The storage system according to claim 3, wherein the inert gas supply path is switched to an open state.   A storage method using the storage system according to any one of claims 1 to 6.

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