JP2005167168A - Purge valve and stocker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a purge valve and a stocker that can decrease a loss of a clean gas at the utmost that is sent to each storage chamber for keeping the cleanness of a stocker's respective chambers and decrease storage costs as well for semiconductor wafers and the like, and can also prevent a nitrogen gas leaking or flowing into a clean room. <P>SOLUTION: More than one independent storage chamber 15 is incorporated and housed in the stocker 14. In each of the storage chambers 15, a purge valve 1 is disposed at its bottom, and a support stand 17 is directly connected to an actuator right above the purge valve 1 so that vertical motion of the support stand 17 may, in turn, become that of the actuator. The support stand 17 is held by a spring 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a storage device that is purged with a clean gas and maintains an effective use of the clean gas in order to maintain the cleanliness in the storage box, and a purge valve for realizing such a storage device.

In the field of semiconductors, particularly in LSI (Large Scale Integration), pattern miniaturization has progressed as the degree of integration has improved, and the size of the pattern has reached submicron, for example, 0.1 μm. The cleanliness of the surrounding environment has been increasingly required.

  Therefore, it is necessary to always maintain and store the wafer carrier for storing the semiconductor wafer, or the FOUP (Front Opening Unified Pod) itself which is a storage box for the wafer itself, especially the FOUP. Therefore, storage containers such as FOUPs are stored in a storage device that is always kept clean, and the cleanliness is maintained.

  In addition, each storage chamber is stored in a separate storage device in order to avoid the influence of cross contamination between adjacent wafer carriers in a state where each storage container, for example, a wafer carrier is stored. In order to maintain the cleanliness of this separate and independent storage chamber containing the storage container, the storage chamber is constantly purged with a clean gas, such as nitrogen gas, through a filter.

  Since the FOUP has an opening hole for introducing a gas, this clean gas is directly introduced into the FOUP, and the inside of the FOUP is purged to maintain the cleanliness. The FOUP is installed on a shelf or the like for storing the storage container and purged with clean gas and stored.

On the other hand, Patent Document 1 discloses a method in which a plurality of wafers are placed in a storage container that can be filled with nitrogen gas, and nitrogen gas is uniformly flowed to maintain the cleanliness of the wafer.
JP2001-338971

  However, the nitrogen gas purged into each storage chamber of the storage device is expensive because it can be produced by vaporizing liquid nitrogen, and the conventional storage device is also purged with nitrogen in a storage chamber in which no wafer carrier or FOUP exists. Therefore, the loss of nitrogen gas is large, and these nitrogen purges have a great influence on the cost because they are performed all night after work as well as during daytime work. Further, if the occupation amount of nitrogen gas itself increases in the atmosphere, the human body may be adversely affected, and the working environment may also be a problem.

The FOUP has one introduction hole and one exhaust hole for purging clean gas at the bottom, and a check valve is attached to the introduction hole and the exhaust hole. The check valve is mounted in the reverse direction as shown in FIG. 4 to introduce and exhaust clean gas into the FOUP. The introduction-side check valve is opened by the gas supply pressure, clean gas enters the FOUP, and the exhaust-side check valve is opened and exhausted by the gas pressure in the FOUP, thereby purging with the clean gas in the FOUP.
However, since the storage device or the storage area is in a state where clean gas is supplied even in the absence of FOUP, the clean gas is sent to places where FOUP does not exist, and the clean gas is consumed wastefully. It was.

  Therefore, the present invention also reduces the storage cost of semiconductor wafers and the like by reducing the loss of clean gas flowing to each storage chamber necessary to maintain the cleanliness of each storage chamber of the storage device, and also in the clean room. The purpose is to suppress nitrogen gas leakage into the tank as much as possible.

  In order to solve the above problems, the present invention can purge clean gas only when it is necessary for purging stored items, for example, a wafer carrier or a wafer storage container FOUP, that is, only in a storage room where these wafer carriers exist. The storage container storage apparatus is configured to provide a purge valve that opens and purges clean gas only when the wafer storage container FOUP and the purge valve are connected, that is, when the presence of the storage container is detected.

  The present invention also provides a valve opening / closing actuator that causes the purge valve to open and close by the weight of a heavy object or a mechanical external force, a gas passage for introducing gas, and a gas introduction hole through which gas enters from a gas supply source when the purge valve is opened. A relay conduction hole for conducting the gas passage and the gas introduction hole through the conduction hole, a sealing material for shutting off the gas flow when the purge valve is closed, a piston rod that is vertically driven to open and close the valve, and a gas flow rate is adjusted. It is composed of an orifice and a spring that operates the actuator depending on the presence or absence of a heavy object. Here, the valve opening / closing actuator refers to an operation portion that opens and closes the valve by a weight or a mechanical external force including the flange (1) 13, the piston rod 8, and the spring (1) 11 in FIG.

The diameter of the orifice can be changed to an arbitrary size, and the amount of flowing gas can be selected arbitrarily. The spring can be changed to an arbitrary spring constant, and the weight of the load or the magnitude of the mechanical external force can be changed. It is characterized in that sensing can be arbitrarily selected.
The storage device has a plurality of separate and independent storage chambers, each of which is provided with a purge valve according to claim 1, and the purge valve is opened only when stored items exist in the storage chamber, and clean gas is stored. The purge valve is installed so as to flow into the room.
Further, according to the present invention, the purge valve and the check valve are connected to the wafer container FOUP having a gas introduction hole and a check valve attached to the gas introduction hole, the purge valve is opened, and the gas is passed through the wafer container FOUP. It is characterized by purging by.
As the clean gas, for example, nitrogen gas, dry air, or inert gas is used.

  Since the purge valve according to the present invention opens and closes depending on whether a weight or mechanical external force is applied to the purge valve operating portion, the valve can be opened and closed by checking the presence or absence of an object. The orifice diameter can be easily changed to an arbitrary size, and the amount of flowing gas can be selected arbitrarily. The spring can be changed to an arbitrary spring constant, and the weight of the load or the magnitude of the mechanical external force can be changed. Since the detection can be selected arbitrarily, the degree of freedom of use of the purge valve is increased, and any specification can be accommodated.

  In order to maintain the cleanliness of each storage room of the storage device, the loss of clean gas flowing to each storage room can be reduced as much as possible, the storage cost is also reduced, and when nitrogen gas is used as the clean gas, Nitrogen gas leakage into the gas can be suppressed as much as possible, and adverse effects on the human body due to nitrogen gas can be reduced.

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of the purge valve of the present invention. The purge valve 1 of the present invention is a valve that opens and closes by weight or mechanical force and controls gas purge by the valve opening and closing operation.
FIG. 1A shows a closed state because there is no heavy object, so that the weight is not applied to the actuator 2 of the purge valve, and FIG. 1B shows the weight of the heavy object on which the purge valve 1 of the present invention is placed. Shows a state in which it is engaged with the actuator 2 of the purge valve 1 and opened. The actuator 2 refers to an operating portion that opens and closes the valve by a weight or mechanical external force including the flange (1) 13, the piston rod 8, and the spring (1) 11.

  Next, the structure of the purge valve 1 of the present invention will be described. In FIG. 1A, a purge valve 1 is an actuator 2 that opens and closes mainly by the weight of a heavy object, a gas passage 23, a conduction hole 4, and a clean gas introduction hole through which clean gas enters from a clean gas supply source when the purge valve 1 is opened. 5. Relay conduction hole 6 for connecting the gas passage 23 and the clean gas introduction hole 5 through the conduction hole 4 when the purge valve 1 is opened, the sealing material (1) 7 for blocking the flow of clean gas when the purge valve 1 is closed, the valve The piston rod 8 that is driven up and down to open and close, the orifice 3 that adjusts the gas flow rate, the valve body housing 10, the sealing material (2) 9 that seals between the piston rod 8 and the valve body housing 10, and the actuator 2 depending on the presence or absence of heavy objects Connected spring (1) 11 to be operated, clean gas supply source and valve body housing 10 That the flange (1) 12 and a flange (2) 13 for connecting the clean gas introducing chamber (not shown) the actuator 2. Here, O-rings are used as the sealing material (1) 7 and the sealing material (2) 9. In FIG. 1B, the same reference numerals are the same as those in FIG.

  Next, the operation of the purge valve 1 of the present invention will be described. In FIG. 1A, a clean gas supply source 18 (not shown) and the valve body housing 10 are connected by a connection flange (1) 12, and an actuator 2 and a storage chamber (not shown) are connected by a flange (2) 13. ing.

  Since there is no heavy object, the actuator 2 remains pushed up by the spring (1) 11 and does not open. Therefore, the sealing material (1) 7 blocks the flow of clean gas when the valve is closed. Since the purge valve 1 is closed, clean gas does not enter the storage chamber.

  In FIG. 1B, since there is a heavy object, the actuator 2 moves downward by overcoming the repulsive force of the spring (1) 11. When the actuator 2 is operated, the piston rod 8 is also moved downward. When the valve is closed, the sealing material (1) 7 for blocking the flow of the clean gas is also moved downward. When the purge valve 1 is opened, the gas passage 23 and the gas introduction hole 5 are moved. Is opened by the relay conduction hole 6 which conducts through the conduction hole. The orifice 3 adjusts the flow rate of the gas flowing through the purge valve. The sliding portion of the piston rod 8 prevents gas leakage by a sealing material (2) 9 between the piston rod 8 and the valve body housing 10.

Accordingly, the clean gas supply source 18, the clean gas supply pipe 19, the clean gas introduction hole 5, the orifice 3, the relay conduction hole 6, the conduction hole 4, the gas passage 23, and the storage room are conducted to the storage room. The clean gas passage from the clean gas supply source 18 flows into the storage room along this route.
As described above, the opening / closing operation of the purge valve 1 according to the present invention is performed according to the presence / absence of a heavy object according to the above operation procedure. Further, the purge valve 1 according to the present invention can open the purge valve 1 by forcibly applying a force in the direction in which the heavy load is applied instead of the heavy load.

Next, a storage device 14 using the purge valve 1 of the present invention will be described with reference to FIGS.
FIG. 2 shows a front view of the storage device 14 of the present invention. The storage device 14 has a plurality of independent storage chambers 15 incorporated therein. In each storage chamber 15, the purge valve 1 is disposed at the bottom, and a support base 17 is directly connected to the actuator 2 and connected immediately above the purge valve 1, and the vertical movement of the support base 17 remains as it is. To be. The support base 17 is supported by a spring (2) 24.
Further, a clean gas supply pipe 19 is connected to the lower side of the purge valve 1, and the clean gas supply pipe 19 is connected to a clean gas supply source 18 so that clean gas can be always supplied. The clean gas to be supplied is, for example, clean nitrogen gas that has passed through a filter (not shown).

When there is nothing in the storage chamber 15 and the chamber is empty, the actuator 2 of the purge valve 1 directly connected to the support base 17 does not operate, and the purge valve 1 is closed and clean gas does not flow into the storage chamber 15.
On the other hand, the wafer carrier 20 containing the semiconductor wafer is opened on the storage device door 16 and placed on the support base 17 in the storage device 14. The actuator 2 is activated, the purge valve 1 is opened, and clean gas flows into the storage chamber 15 from the clean gas supply source 18 through the clean gas supply pipe 19.

  A case where the present invention is applied to a FOUP as a storage container will be described with reference to FIG. Two check valves 22 are provided at the bottom of the FOUP main body 21, and the directions of the check valves 22 are attached in reverse directions because of the difference in operation of introducing and exhausting clean gas. When the FOUP main body 21 is placed in the storage device or storage area, the clean gas is connected to the check valve 22 on the introduction side to the purge valve 1 of the present invention, the purge valve 1 is opened, and the clean gas enters the FOUP main body 21. The exhaust side check valve 22 is opened by the FOUP internal pressure, and the clean gas is exhausted and the interior of the FOUP main body 21 is purged from the clean gas.

  The storage device 14 according to the present invention, in combination with the purge valve 1 according to the present invention, is an amount necessary only when clean nitrogen gas is required, that is, when there is a stored item in the storage chamber 15 (the diameter of the orifice 3 is arbitrarily set). The amount of inflow gas can be controlled by selecting and exchanging appropriately.) The nitrogen gas can be sent into the storage chamber 15. Further, the weight (opening / closing) of the purge valve 1 or the mechanical external force can be arbitrarily set by selectively replacing the spring (1) 11 for operating the actuator 2 depending on the presence or absence of a heavy object with an appropriate spring constant. Also. In addition to nitrogen gas, clean gas includes dry gas or inert gas such as argon gas.

It is sectional drawing which shows the closed state of the purge valve by this invention. It is sectional drawing which shows the state which the purge valve by this invention opened. 1 shows a front view of a storage device according to the invention. FIG. 3 shows a cross-sectional view of an air introduction chamber of a storage device according to the present invention. It is the schematic which shows the attachment position of the check valve of FOUP.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Purge valve 2 Actuator 3 Orifice 4 Conduction hole 5 Gas introduction hole 6 Relay conduction hole 7 Sealing material (1)
8 Piston rod 9 Sealing material (2)
10 Valve body housing 11 Spring (1)
12 Flange (1)
13 Flange (2)
14 Storage device 15 Storage chamber 16 Storage device door 17 Support base 18 Clean gas supply source 19 Clean gas supply pipe 20 Wafer carrier 21 FOUP body 22 Check valve 23 Gas passage 24 Spring (2)

Claims (6)

A valve opening / closing actuator that opens and closes the valve by the weight of a heavy object or a mechanical external force, a gas passage for introducing gas, a gas introduction hole for introducing gas from a gas supply source when the valve is opened, and a gas passage and a gas introduction hole Relay through hole that conducts through the conduction hole, a sealing material that shuts off the gas flow when the valve is closed, a piston rod that moves up and down to open and close the valve, an orifice that adjusts the gas flow rate, and a heavy object or mechanical A purge valve composed of a spring that activates the actuator depending on the presence or absence of external force. The purge valve according to claim 1, wherein the orifice has a diameter exchanged to an arbitrary size, and an amount of flowing gas can be arbitrarily selected. 3. The purge valve according to claim 1, wherein the spring is replaced with one having an arbitrary spring constant, and the weight of the load or the sensing of a mechanical external force can be arbitrarily selected. A plurality of separate and independent storage chambers are provided, and the purge valves according to claim 1, 2, or 3 are provided in the storage chambers, and the purge valves are opened only when stored items exist in the storage chambers. The storage device is characterized in that the purge valve is installed so that gas flows into the storage chamber. The purge valve and the check valve are connected to a gas inlet hole and a wafer container FOUP having a check valve attached to the gas inlet hole, and the purge valve is opened to purge the wafer container FOUP with the gas. Feature storage device. 6. The storage device according to claim 4, wherein the gas is nitrogen gas, dry air, or inert gas.

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