JPH09153437A - Gas feed/exhaust system of portable closed container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the freedom of a placement in a clean room and the safety health of operators, who operate in the room, by a method wherein inert gas, which is evacuated from a gas substituting device, is changed into mixed gas, which does not exert an effect on the operators, and the mixed gas is exhausted in the clean room. SOLUTION: This system is provided with a portable closed container 2, which is housed with semiconductor wafers W and is closed, a gas substituting device 3 for substituting the air in the contaniner 2 for inert gas and a gas exhaust tube for evacuating exhaust gas, which is exhausted from the device 3 and contains the inert gas, outside of a clean room 1. At this time, a gas exhaust device 16 of a structure, wherein the exhaust gas, which is evacuated from the device 3, is mixed with oxygen gas and the concentration of the mixed gas subsequent to this mixing is set into a concentration in a prescribed concentration ragion (c) that does not exert an effect on the human body to exhaust the mixed gas in the room 1, is connected with the gas exhaust tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable container used for transferring semiconductor wafers in a clean room, and more particularly to a gas supply / exhaust system for replacing the inside of the portable container with an inert gas atmosphere.

[0002]

2. Description of the Related Art Semiconductors are manufactured in a clean room whose internal atmosphere has been cleaned. However, even during transportation between the respective steps in the clean room, a clean environment equal to or higher than that in the semiconductor processing apparatus is used. Thus, it has begun to be attempted to store the semiconductor wafers in a stepwise manner in a portable airtight container. Furthermore, when semiconductors are manufactured to the limit of microfabrication and the film thickness is thin and the conductor wires are extremely thin, ultra-thin oxide films due to natural oxidation of semiconductor wafers become a problem, and gas inside the portable airtight container becomes a problem. By supplying an inert gas (for example, nitrogen gas) with a replacement device, oxygen that causes natural oxide film growth on semiconductor wafers is released to the outside of a portable sealed container, and the internal atmosphere inside the container is replaced with an inert gas. doing.

As a gas supply / exhaust system for replacing the internal atmosphere of the portable airtight container with the inert gas as described above, the present inventor has proposed the one shown in FIG. 3 and will be described below. In FIG. 3, a gas supply / exhaust system for a portable closed container is composed of a gas replacement device 3 arranged in a clean room 1 and a gas exhaust pipe 4, and an inert gas (for example, an inert gas (eg, , Nitrogen gas), which is replaced by a portable airtight container 2 (hereinafter, simply, the airtight container 2
That. ) Is placed. This hermetic container 2 has a lid 2A that covers a wafer cassette 7 that houses a semiconductor wafer W therein.
It is placed on top and stored airtightly. Further, the gas replacement device 3 is provided with an elevating device 6 having an elevating table 5 therein, and the elevating table 5 has an upper opening 3A of the gas replacement device 3.
It is fitted inside to make the gas replacement device 3 airtight. Further, in the gas replacement device 3, an air supply pipe 8 that connects an inert gas supply device (not shown) to the upper opening 3A, and an exhaust pipe that exhausts the inert gas supplied from the inert gas supply device. 4 and 4 are connected to each other. The gas exhaust pipe 4 is composed of an exhaust pipe 9 that opens into the gas replacement device 3 and a main exhaust pipe 4A that is continuous with the exhaust pipe 9 and extends to the outside of the clean room 1. The main exhaust pipe 4A is arranged below the floor plate 15 (grating) with holes in the clean room 1 so as not to interfere with the operation of the semiconductor manufacturing equipment and the like (not shown) arranged in the clean room 1 and the transfer equipment. In addition, the exhaust gas from not only the gas replacement device 3 but also the semiconductor device or the like can be exhausted at once. Reference numeral 10 is an air supply valve arranged in the air supply pipe 8, 11 is an exhaust valve arranged in the exhaust pipe 9, and 12 is a main exhaust pipe 4A for sucking exhaust gas of each device and discharging it to the outside of the clean room. Suction fan, 13 is a suction fan 12
It is a filter that removes dust and dirt present in the exhaust gas and the like sucked in.

In order to replace the inside of the closed container 2 with an inert gas, the closed container 2 is placed on the gas replacement device 3 and the lift 5 of the lifting device 6 in a state of covering the opening 3A of the gas replacement device 3. After airtightly mounted over the airtight container, the lid 2A of the hermetically sealed container 2 is opened by coupling with the lifting table 5.
Then, the elevating table 5 is lowered together with the lid 2A and the wafer cassette 7 to bring the inside of the closed container 2 and the gas replacement device 3 into communication with each other, and then the air supply valve 10 and the exhaust valve 11 are opened and the suction fan 12 is opened. Operate. Thereby, the inert gas is supplied from the inert gas supply device to the gas replacement device 3,
After the oxygen gas or the like, which is supplied into the closed container 2 and causes the natural oxide film growth of the semiconductor wafer W, is sucked together with the inert gas as the exhaust gas by the suction fan 12 and passes through the exhaust pipe 6 and the main exhaust pipe 4A, When passing through the filter 13, the air in the clean room 1 is also sucked from the floor plate 15 with holes and released to the outside of the clean room 1. After that, when a predetermined time elapses and the purity of the inert gas in the gas replacement device 3 and the closed container 2 is increased and replaced, the air supply valve 10 and the exhaust valve 11 are closed and the gas replacement device 3 is operated. After the supply of the inert gas and the exhaust of the exhaust gas from the gas replacement device 3 are stopped, the lifting table 5 of the lifting device 6 is lifted together with the lid 2A and the wafer cassette 7 to hermetically seal the wafer in the hermetic container 2. Store the cassette 7.

By the way, in the gas supply / exhaust system of the portable closed container proposed by the inventor of the present invention, the traveling route of the semiconductor manufacturing device arranged in the clean room and the transport device traveling in the clean room is secured. Therefore, there is no guarantee that the gas replacement device will be installed near the main exhaust pipe of the gas exhaust pipe, and if it is placed away from this main exhaust pipe, the exhaust pipe will become longer and longer. It is assumed that the exhaust resistance of the exhaust gas passing through the exhaust pipe increases and the exhaust cannot be performed properly. As a result, there arises a problem that the replacement performance of the gas replacement device that replaces the internal atmosphere of the closed container with the inert gas deteriorates.

[0006]

In order to solve this problem, the exhaust gas exhausted from the gas replacement device is directly discharged into the clean room without passing through the main exhaust pipe. The length can be shortened, and the deterioration of the replacement performance of the gas replacement device due to the increase in the exhaust resistance of the exhaust pipe can be solved.
Further, the gas replacement device can be freely arranged in the clean room without noticing the installation position of the main exhaust pipe.

However, when the exhaust gas from the gas replacement device is released into the clean room, the concentration of the exhaust gas in the clean room increases, resulting in a lack of oxygen. As a result, workers in the clean room are more likely to develop an oxygen deficiency condition, and even if they do not immediately develop an oxygen deficiency condition, they are likely to fall into an oxygen deficiency condition at any time. Will be done. Further, since the exhaust gas from the gas replacement device is discharged into the clean room, there is a problem in that it is not preferable in hygiene.

The present invention has been made to solve this problem, and changes the inert gas exhausted from the gas replacement device into a mixed gas that does not affect the operator and discharges it into the clean room. Thus, a gas supply / exhaust system for a portable closed container is provided, which can achieve the degree of freedom of arrangement in the clean room and the safety and health of workers who work in the clean room.

[0009]

In order to solve the above problems, in a gas supply / exhaust system for a portable closed container according to the present invention, in claim 1, a portable closed container for accommodating and sealing a semiconductor wafer, A gas replacement device for replacing the inside of the portable closed container with an inert gas, and a gas exhaust pipe for discharging exhaust gas containing the inert gas exhausted from the gas replacement device to the outside of the clean room. In the gas supply / exhaust system for a portable closed container, the exhaust gas exhausted from the gas replacement device is mixed with oxygen gas in the gas exhaust pipe, and the concentration of the mixed gas after the mixing does not affect the human body. A gas exhaust device for discharging into the clean room as a predetermined concentration region is connected. As a result, oxygen gas is mixed with the exhaust gas of the gas replacement device, and the concentration of the mixed gas after mixing is set to a predetermined concentration that does not affect the worker working in the clean room, and the mixed gas is discharged into the clean room. You can

In the second aspect, in addition to the first aspect,
The gas exhaust device includes a gas mixing chamber for mixing the exhaust gas exhausted from the gas replacement device through the gas exhaust pipe and an oxygen gas supplied from the outside, and a mixed gas mixed in the gas mixing chamber. Gas concentration detection means for detecting the concentration of the inert gas or acidity gas, flow rate control means for changing the flow rate of the oxygen gas supplied into the gas mixing chamber, and a detection signal from the gas concentration detection means A controller for controlling the flow rate control means so that the concentration of the inert gas or oxygen gas in the mixed gas mixed in the gas mixing chamber is within a gas concentration setting region that does not affect the human body, A clean room for cleaning the mixed gas with a filter and discharging the mixed gas. As a result, the control device controls the flow rate control device based on the detection signal from the gas concentration detection device so that the flow rate of the oxygen gas supplied to the gas mixing chamber becomes the flow rate of the exhaust gas exhausted from the gas replacement device. Depending on the change, the control is made surely so that it is within the gas concentration setting area of the inert gas or oxygen gas in the gas mixture chamber so that it does not affect the workers working in the clean room. , Can be released into the clean room.

According to a third aspect, in addition to the second aspect,
The controller is connected to a concentration setter capable of changing the gas concentration setting region. Thereby, the gas concentration setting region of the inert gas or the oxygen gas in the mixed gas in the gas mixing chamber can be set according to the environment in the clean room.

According to a fourth aspect of the present invention, the gas replacement device and the gas exhaust device are integrally formed as in the first or second aspect. As a result, the gas supply / exhaust system becomes compact and can be easily transported.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A gas supply / exhaust system for a portable closed container according to an embodiment of the present invention will be described below. FIG. 1 is a schematic diagram showing a gas supply / exhaust system for a portable airtight container according to an embodiment of the present invention, and FIG. 2 is a gas replacement device constituting a gas supply / exhaust system for a portable airtight container according to an embodiment of the present invention. FIG. 3 is a vertical cross-sectional view in which a gas exhaust device is integrated. 1 and 2, the same reference numerals as those in FIG. 3, which is the system proposed by the inventor of the present application, indicate the same members, and thus the description thereof will be omitted.

In FIG. 1, a gas supply / exhaust system for a portable closed container according to an embodiment of the present invention is a system proposed by the inventor of the present invention. The exhaust gas [mixed gas of inert gas (for example, nitrogen gas) and oxygen gas (air)] exhausted from the gas replacement device 3 can be exhausted into the clean room 1 by connecting. This gas exhaust system 1
Reference numeral 6 denotes a gas mixing chamber 17, a flow rate control valve 18 serving as a flow rate control means for changing the flow rate of oxygen gas supplied into the gas mixing chamber 17, and a gas replacement device 3 supplied into the gas mixing chamber 17. A gas concentration sensor 19 which is a gas concentration detecting means for detecting the concentration of a mixed gas of exhaust gas and oxygen gas,
The control device 10 that controls the opening degree of the flow rate control valve 18 based on the output of the gas concentration sensor 19, and the clean room 21 that cleans the mixed gas from the mixing room 17 and discharges it into the clean room 1 are the main parts. It is configured.

The gas mixing chamber 17 communicates with the clean chamber 21 through the throttle tube 23. This clean room 21 has a throttle tube 23
The side opposite to the side wall 21a that is open is opened in the clean room 1, and the filter 13 is inserted from this open side to define the fluid radiation space A with the side wall 21a. Further, the throttle pipe 23 that connects the gas mixing chamber 17 and the clean chamber 21 has a smaller diameter than the chambers 17 and 23.
That is, as will be described later, a state in which a mixed gas of exhaust gas exhausted from the gas replacement device 3 into the gas mixing chamber 17 and oxygen gas supplied from an oxygen gas storage device (not shown) is squeezed from the gas mixing chamber 17. So as to radially flow out to the fluid radiating space A in the clean room 21 through the throttle pipe 23,
The diameter of the throttle tube 23 is smaller than that of each chamber 17, 21.

Further, an exhaust pipe 9 connected to the gas replacement device 3 is opened at a side wall 17a of the gas mixing chamber 17 opposite to the side wall at which the throttle pipe 23 is opened. A suction device 25 (for example, a pump, a fan, etc.) that sucks the exhaust gas exhausted from the displacement device 3 and supplies the exhaust gas into the gas mixing chamber 17 is arranged. Then, the flow direction a of the exhaust gas supplied from the exhaust pipe 9 into the gas mixing chamber 17
The oxygen gas supply pipe 22 for supplying the oxygen gas stored in the oxygen gas storage device (not shown) into the gas mixing chamber 17 from the direction orthogonal to the
It opens to 7b.

Further, in the oxygen gas supply pipe 22, a suction device 30 (for example, a pump) for sucking oxygen gas from the oxygen gas storage device in order from the oxygen gas storage device side toward the gas mixing chamber 17. , A fan, etc.) and the flow rate control valve 18 are arranged. The flow rate control valve 18 is connected to the control device 20 together with the suction devices 25 and 30 arranged in the exhaust pipe 9 and the oxygen gas supply pipe 22, respectively, and operates based on various commands of the control device 20. .

The gas concentration detecting means 19 comprises a gas mixing chamber 17
Is placed in a throttle tube 23 that connects the clean room 21 with the clean room 21,
Content rate of oxygen gas (oxygen gas concentration) in the mixed gas composed of exhaust gas and oxygen gas mixed in the gas mixing chamber 17
Which is an oxygen gas concentration detection sensor (hereinafter referred to as oxygen gas concentration detection sensor 19) for detecting the oxygen gas concentration detection signal b according to the oxygen gas concentration of the mixed gas passing through the throttle pipe 23. Send out. Here, the oxygen gas concentration detection sensor 19 uses, for example, a magnetic wind type or pressure detection type magnetic oximeter that utilizes the characteristics of oxygen gas known as paramagnetic gas that generates a small number of magnetic moments. To be

When the control device 20 receives the oxygen gas concentration detection signal b from the oxygen gas concentration detection sensor 19, the control device 20 does not affect the human body preset inside the oxygen gas concentration detection signal b or input by the concentration setting device 16. The oxygen gas concentration region data c (for example, the upper limit value of the oxygen concentration region data is set to 30% and the lower limit value is set to 18%) is compared with the oxygen gas concentration detection signal b, and the flow control valve is compared. The valve opening degree command d (voltage) that determines the valve opening degree of 18 is sent to the flow control valve 18, and the operation command e is sent to each of the suction devices 25 and 30.
Is sent.

The gas supply / exhaust system according to the embodiment of the present invention is configured as described above. Next, the operation of the gas supply / exhaust system will be described. For convenience of explanation,
The air supply valve 10 and the flow rate control valve 18 in the air supply pipe 8 are in a closed state, the suction devices 25 and 30 are not in operation, and the lift 5 is located above the gas replacement device 3. 3A
It is assumed that the inside of the gas replacement device 3 is fitted into the inside to make the inside of the gas replacement device airtight.

First, in order to replace the inside of the closed container 2 with an inert gas, the closed container 2 is covered with the gas replacement device 3 and the lifting table 5 of the lifting device 6 while covering the opening 3A of the gas replacement device 3. After air-tightly mounting, the elevating table 5 is raised to be connected to the lid 2A of the closed container 2 through the opening 3A and opened. Then, the elevating table 5 is lowered together with the lid 2A and the wafer cassette 7 to bring the inside of the portable container 2 into communication with the gas replacement device 3, and then the air supply valve 10 is opened to supply an inert gas supply device (not shown). An inert gas (for example, nitrogen gas) is supplied into the gas replacement device 3 and the closed container 2. At this time, the control device 20 sends an operation command e to the suction device 25 in the exhaust pipe 9 as an initial condition to operate the suction device 25. As a result, the suction device 25 sucks the exhaust gas from the gas replacement device 3 and flows through the exhaust pipe 9 into the gas mixing chamber 17 of the gas exhaust device 16.

At the same time as the operation of supplying the inert gas to the gas replacement device 3, the controller 20 controls the oxygen gas supply pipe 22.
An operation command e and a valve opening command d are sent to each of the suction device 30 and the flow rate control valve 18 therein. Thereby, the suction device 3
0 sucks oxygen gas from the oxygen gas storage device and flows out to the gas mixing chamber 17 of the gas exhaust device 16 through the oxygen gas supply pipe 22 and the flow rate control valve 18. The exhaust gas exhausted from the exhaust pipe 9 and the oxygen gas supplied from the oxygen gas supply pipe 22 flow into the gas mixing chamber 17 so that their flow directions are orthogonal to each other.
It will be well mixed in 7.

Then, the mixed gas of the exhaust gas and the oxygen gas mixed in the gas mixing chamber 17 passes through the throttle pipe 23 in a state of being throttled from the gas mixing chamber 17, and then becomes larger than the throttle pipe 23. It flows out radially into the fluid radiating space A in the clean room 21. As described above, when the mixed gas from the gas mixing chamber 17 passes through the throttle tube 23, the oxygen gas concentration detection sensor 19 detects the oxygen gas concentration of the mixed gas passing through the throttle tube 23, and the oxygen of the mixed gas is detected. An oxygen gas concentration detection signal b corresponding to the gas concentration is sent to the control device 20. Then, the control device 20, which has received the gas concentration detection signal b from the oxygen gas concentration detection sensor 19, receives the oxygen gas concentration region data c preset or input and set by the concentration setting device 26 and the gas concentration detection signal. For example, when the oxygen gas concentration of the mixed gas passing through the throttle pipe 23 is equal to or lower than the lower limit value of the oxygen gas concentration region data c that does not affect the human body, the open degree of the flow control valve 18 is set to the maximum. The valve opening command d is sent to the flow rate control valve 18, and the opening degree of the flow rate control valve 18 gradually increases as the oxygen gas concentration goes from the lower limit value to the upper limit value of the oxygen gas concentration region data c that does not affect the human body. A valve opening command d that makes the flow rate control valve 18 smaller is sent. Accordingly, the flow rate control valve 18 changes the degree of valve opening based on the degree of valve opening degree command d from the control device 10 to change the passage flow rate of the oxygen gas sucked by the suction device 30 from the oxygen gas storage device. It is controlled to change the flow rate of the oxygen gas flowing into the gas mixing chamber 17. As a result, the gas mixing chamber 17 is adjusted so that the oxygen gas concentration in the mixed gas discharged into the clean room 1 falls within the oxygen gas concentration region data c according to the amount of exhaust gas discharged from the gas replacement device 3. It is possible to change the flow rate of the oxygen gas from the oxygen gas storage device through the suction device 30 and the flow rate control valve 18 and allow the oxygen gas to flow out.

The mixed gas that has passed through the throttle tube 23 from the gas mixing chamber 18 radially flows out into the fluid radiating space A in the cleaning chamber 16 and is discharged from the entire surface of the filter 13 inserted in the cleaning chamber 16. Dust and dust existing in the mixed gas when flowing into the inside and passing through the filter 13 are removed and then released into the clean room 1 from the opening of the clean room 16, which is released. Since the mixed gas has an oxygen gas concentration that does not affect the human body, the worker who works in the clean room 1 does not fall into the oxygen deficiency condition, and can work safely and hygienically.

After that, when a predetermined time has elapsed and the purity of the inert gas in the gas replacement device 3 and the hermetically sealed container 2 is increased and replaced, the air supply valve 10 and the flow control valve 18 are closed, and at the same time, After stopping the suction devices 25 and 30 to stop the supply of the inert gas to the gas replacement device 3 and the exhaust of the exhaust gas from the gas replacement device 3, the lifting table 5 of the lifting device 6 is covered with the lid 2.
A, ascending together with the wafer cassette 7 to form a closed container 2
The wafer cassette 7 is hermetically housed therein, and the replacement of the closed container 2 with the inert gas is completed.

In the gas supply / exhaust system for the portable airtight container according to the embodiment of the present invention, the gas replacement device 3 and the gas exhaust device 16 are separately provided, but the present invention is not limited to this. Not as shown in Figure 2,
The gas replacement device 3 and the gas exhaust device 16 may be formed integrally in series. In this case, as shown in FIG. 2, the gas mixing chamber 17 is formed integrally with the lower side of the gas replacement device 3 continuously.
A clean room 21 is provided in the inside 7. In addition, the check valve 2 that blocks the flow of the mixed gas from the gas mixing chamber 17 is provided in the exhaust pipe 9 that connects the gas replacement device 3 and the gas mixing chamber 17.
7 are arranged. Then, in order to successfully mix the exhaust gas exhausted from the gas replacement device 3 and the oxygen gas supplied from the oxygen gas storage device in the gas mixing chamber 17, the oxygen gas supply pipe 22 is connected to the exhaust pipe 9 From the direction orthogonal to the flow direction “a” of the exhaust gas supplied into the gas mixing chamber 17 from the above, the inside of the gas mixing chamber 17 was opened, and the cleaning chamber 21 was provided directly below the oxygen gas supply pipe 22. The operation of the gas supply / exhaust system for the portable airtight container in FIG. 2 is performed in the same manner as the gas supply / exhaust system shown in FIG.
Further, in FIG. 2, the suction device 25 is not necessary because the inert gas is fed into the gas mixing chamber 17 by the flow rate of the inert gas because it is integrated in series.

In the portable airtight container gas supply / exhaust system shown in FIGS. 1 and 2, an oxygen gas concentration detecting sensor is used as the gas concentration detecting means 19. The present invention is not limited to this, and a nitrogen gas concentration detection sensor that detects the concentration of nitrogen gas that is an inert gas in the mixed gas mixed in the gas mixing chamber 17 may be used. In order to promote the mixing of the exhaust gas from the gas replacement device 3 and the oxygen gas from the oxygen gas storage chamber in the gas mixing chamber 17, as shown in FIG. A stirring device 24 may be provided.
Further, although the filter 13 may be conventionally used, it has a performance that the collection rate of fine particles is high and the pressure loss due to the filter itself is extremely low depending on the environment in the clean room 1. High-performance filter (HE
PA filter) or ultra high performance filter (HEPA
An ultra-high performance filter (ULPA filter) having a performance equal to or higher than that of a filter may be used. Further, in the gas supply / exhaust system of the portable closed container of FIGS. 1 and 2 according to the present invention, it has been described that the mixed gas mixed in the gas mixing chamber 17 is discharged into the clean room 1.
It may be released to the outside of the clean room 1. If it is known in advance that the amount of inert gas contained in the exhaust gas exhausted from the gas replacement device 3 is small, an air reservoir may be installed in place of the oxygen gas reservoir to supply air. . Further, in the clean room 1 where semiconductors are manufactured, air conditioning is usually performed to maintain the cleanliness. Therefore, in the gas supply / exhaust system of the portable closed container shown in FIGS. 1 and 2, the air in the clean room 1 is directly connected without connecting the oxygen gas storage or the air storage to the oxygen gas supply pipe 22. The oxygen gas supply pipe 22 may be sucked by the suction device 30 and supplied into the gas mixing chamber 17.

[0028]

As described above, according to the gas supply / exhaust system for a portable airtight container of the present invention, in the first aspect, the inert gas of the gas replacement device is mixed with the oxygen gas, and the mixed gas after mixing is mixed. The concentration can be set to a predetermined concentration that does not affect the worker who works in the clean room, and can be released into the clean room. As a result, the worker in the clean room can work safely and with peace of mind, and the degree of freedom of arrangement in the clean room increases.

In the second aspect, in addition to the effect of the first aspect, the control device controls the flow rate control means on the basis of the detection signal from the gas concentration detection means to supply the oxygen gas to the gas mixing chamber. By changing the flow rate of the gas according to the flow rate of the exhaust gas exhausted from the gas replacement device, an inert gas of the mixed gas in the gas mixing chamber or oxygen so as not to affect the worker working in the clean room. It is possible to surely control the gas so that it is within the gas concentration setting region and release it into the clean room. As a result, the worker in the clean room can work safely and with peace of mind, and the degree of freedom of arrangement in the clean room increases.

In the third aspect, in addition to the effect of the second aspect, the gas concentration setting region of the inert gas or the oxygen gas in the mixed gas in the gas mixing chamber can be set according to the environment in the clean room. .

According to claim 4, in addition to the effect of claim 1 or claim 2, the gas supply / exhaust system is made compact, the transportation can be performed easily, and the space in the clean room is used without waste. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a gas supply / exhaust system for a portable closed container according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view in which a gas purging station and a gas exhausting device that constitute a gas supply / exhaust system of a portable closed container according to an embodiment of the present invention are integrated.

FIG. 3 is a schematic diagram showing a gas supply / exhaust system for a portable closed container proposed by the inventor of the present application.

[Explanation of symbols]

 W semiconductor wafer 1 clean room 2 portable closed container 3 gas replacement device 4 gas exhaust pipe 13 filter 16 gas exhaust device 17 gas mixing chamber 18 flow control valve (flow control means) 19 oxygen gas concentration detection sensor (gas concentration detection means) 20 control device 21 clean room 26 concentration setting device b oxygen gas concentration detection signal c oxygen gas concentration region data

Claims (4)

[Claims] 1. A portable airtight container for housing and sealing a semiconductor wafer, a gas replacement device for replacing the inside of the portable airtight container with an inert gas, and the inert gas exhausted from the gas replacement device. In a gas supply / exhaust system for a portable closed container, which comprises a gas exhaust pipe for discharging exhaust gas containing the gas to the outside of the clean room, the gas exhaust pipe includes the exhaust gas exhausted from the gas replacement device as oxygen gas. A gas supply / exhaust system for a portable closed container, which is connected to a gas exhaust device for mixing the mixed gas and releasing the concentration of the mixed gas into the clean room as a predetermined concentration region that does not affect the human body. . 2. The gas exhaust device includes a gas mixing chamber for mixing the exhaust gas exhausted from the gas replacement device through the gas exhaust pipe with an oxygen gas supplied from the outside, and a gas mixing chamber for mixing in the gas mixing chamber. From the gas concentration detection means, a gas concentration detection means for detecting the concentration of the inert gas or the acidity gas of the mixed gas, a flow rate control means for changing the flow rate of the oxygen gas supplied into the gas mixing chamber, Based on the detection signal of, the flow rate control means is controlled so that the concentration of the inert gas or oxygen gas in the mixed gas mixed in the gas mixing chamber is within a gas concentration setting region that does not affect the human body. The gas supply / exhaust system for a portable closed container according to claim 1, further comprising a control device and a cleaning chamber for cleaning the mixed gas with a filter and discharging the mixed gas. 3. The gas supply / exhaust system for a portable airtight container according to claim 1, wherein the controller is connected to a concentration setter capable of changing the gas concentration setting region. 4. The gas supply / exhaust system for a portable closed container according to claim 1, wherein the gas replacement device and the gas exhaust device are integrally formed.