JPH02146400A - Cylinder cabinet - Google Patents

Abstract

PURPOSE:To increase safety by closing some sections, from which gas may be leaked, of gas cylinders and gas feed pipes housed in a cylinder cabinet and providing exhaust gas lines in the closed sections. CONSTITUTION:A cylinder 2a in a cylinder cabinet 1 is contains inert gas and cylinders 2b and 2c contain dangerous gas. These cylinders are stored in independent cylinder cabinets 3a, 3b and 3c, respectively and the cabinets 3b and 3c are separated into two upper and lower rooms by a partition. Cylinder valves and gas feed pipe devices from which gas may be leaked are housed in the upper closed rooms 4b and 4c. Also gas detectors 5b and 5c, gas intaking ports 6b and 6c, gas returning ports 7b and 7c, etc. are provided. If gas leakage occurs, exhaust dampers 8b and 8c are opened to exhaust the residual gas in the closed room to the outside of a clean room through exhaust gas lines 10b and 10c. Thus gas leakage can be discovered earlier and diffusion of gas to the other cabinets can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cylinder cabinet for accommodating raw material gas cylinders used in various thin film forming processes, fine pattern etching processes, etc. This relates to cylinder cabinets installed in commercial clean rooms.

[Prior Art] (Background of the Invention) As the degree of integration of semiconductor integrated circuits increases, the cleanliness of clean rooms in which these semiconductors are manufactured has also improved. As a result, the running costs of clean rooms are also rising.

This increase in clean room running costs is due to
In order to reduce product costs, it is necessary to suppress increases in clean room running costs, as this has a direct impact on increases in product costs. One way to reduce running costs is to operate clean rooms in an energy-efficient manner, but the current situation is far from being energy-saving.

Approximately 60% of the running cost of a clean room is said to be related to air conditioning and clean air transportation, but one way to improve cleanliness is to exhaust clean air in excess. This is a major cause of increasing lining costs.

An example of this is as follows.

As mentioned above, when operating a clean room, clean air is discharged in order to improve the cleanliness, but there are other purposes for discharging clean air as follows.

Many special gases are used to manufacture semiconductor integrated circuits, but most of these special gases are toxic,
It is a corrosive and flammable hazardous gas.Normally, at manufacturing sites, special gases are supplied to semiconductor manufacturing equipment from gas cylinders through gas supply piping. The air inside the cabinet is constantly exhausted to prevent disasters such as gas leaks. However, since such exhaust is performed while replenishing clean air from the clean room, clean air is constantly being exhausted.

In addition, new types of special gases are being used one after another for the purpose of forming high-quality thin films and high-quality etching in the production of semiconductor integrated circuits, but as mentioned above, they are toxic,
These are dangerous gases that are corrosive and flammable, and safety management is essential when storing these special gases.

If these special gases were to leak from a gas cylinder or gas supply pipe for some reason, it could cause disasters such as gas poisoning to the human body, material deterioration due to equipment corrosion, or fire or explosion. There is a risk that they may become connected.

Therefore, at present, gas leak detectors are used to detect gas leaks depending on the gas used, and the inside of the cylinder cabinet is constantly evacuated.

However, if the cabinet is constantly exhausted, even if a gas leak actually occurs, it may not be detected instantaneously because the gas inside the cabinet is thin.

In fact, corrosive gas leaks over a long period of time in areas that are not detected by gas leak detectors, resulting in deterioration such as rust formation on gas supply piping equipment in cylinder cabinets. What happens is common.

(Current Prior Art) Figures 1 and 6 are front views showing conventionally used cylinder cabinets.

Normally, one to six gas cylinders (some as many as ten) are housed in one cylinder cabinet, and these cylinder cabinets are used in semiconductor manufacturing factories to accommodate semiconductor manufacturing equipment. 100
~200 units have been installed.

The example shown in FIG. 16 is a gas cylinder 1 with an internal volume of 471.
It is a cylinder cabinet that houses books and two gas cylinders with an internal volume of 10 JI. As shown in Figure 13,
When the front cover (door) 15 of the cylinder cabinet 1 is opened, the interior of the cylinder cabinet 1 becomes one room, which can accommodate gas cylinders 2a, 2b, 2c, a piping vibrator, a balzo, a meter, and other gas supply piping equipment. It has become.

Many of the gas cylinders housed in the cylinder cabinet 1 contain dangerous gases such as toxic, corrosive, and flammable gases, and for some reason gas may escape from the gas cylinders, gas cylinder connections, or gas supply piping equipment. In the unlikely event that a leak occurs and the leaked gas spreads into the clean room of a manufacturing factory, it may cause serious physical effects on the workers inside the clean room, potentially leading to a major accident (disaster).

In addition, if the leaked gas is completely contained within the cylinder cabinet 1, the dangerous gas will remain in the cylinder cabinet 1 in a highly concentrated state, resulting in equipment deterioration (metallic materials such as stainless steel used). This may lead to rust on the parts and deterioration of the resin. Alternatively, if the front cover of the cylinder cabinet is opened without noticing a gas leak, the worker may instantly inhale highly concentrated gas, which could lead to gas poisoning or injury.

Therefore, in order to prevent disasters and increase safety, the inside of the cylinder cabinet is constantly vented to create a slightly negative pressure, so that even if gas leaks, it will be sucked into the exhaust side and will not spread to the clean room side. In some cases, gas leak detectors are installed to detect the leakage of potentially dangerous gases (in addition, fire sensors, heat-sensitive sensors, and smoke sensors to detect ignition of flammable gases, Some are equipped with detectors, etc.)

The exhaust inside the cylinder cabinet is normally performed through an exhaust duct with a diameter of 100 to 150 mm provided on the top plate of the cylinder cabinet, and the exhaust continues while the clean room is in operation. While exhausting the inside of the cylinder cabinet, clean air from the clean room is sucked in through the suction port provided on the front cover of the cylinder cabinet or the gap between the front cover and the cylinder cabinet body. Note that clean air is constantly replenished into the cylinder cabinet and discharged outside the clean room.

Many of the gases used in semiconductor manufacturing have a higher specific gravity than air, so if a gas leak were to occur,
The leaked gas will fall to the bottom of the cylinder cabinet. Therefore, when exhausting the inside of the cylinder cabinet, it is more effective to exhaust the air from the bottom of the cylinder cabinet than simply from the top plate of the cylinder cabinet. When the exhaust duct connection port is provided on the top plate of the cylinder cabinet, such as in a cylinder cabinet, it is difficult in manufacturing the cylinder cabinet to provide the exhaust intake port at the bottom so that the exhaust can be exhausted from the bottom of the cylinder cabinet. may be accompanied by

On the other hand, as a method for detecting gas leakage, it is common to use the aforementioned gas leakage detector.

There are two methods for detecting gas in gas leakage: forced suction type and diffusion type.
The street is heavily used. All of these systems have a mechanism in which gas leaking within the cylinder cabinet is moved by diffusion or suction, and comes into contact with a detector to detect gas leakage.

However, in conventional cylinder cabinets that house multiple gas cylinders, the interior is one room, and leaked gas is diffused and diluted while reaching the gas leak detector. Even if a leak occurs, it will be difficult to detect if the level of leak is extremely small.

Gas leak detectors have different minimum leak detection sensitivities depending on the gas being detected, but when gas leaks and the gas concentration reaches the preset gas leak detection concentration, Leakage will be detected. Furthermore, considering that each gas has its own permissible concentration, the time required to detect a gas leak varies. However, early detection of gas leaks is most important for safety management.
It is necessary to improve the ability to detect gas leaks (possible ways to increase gas leak detection ability include improving the detection sensitivity of gas leak detectors and devising cylinder cabinets).

[Problems to be solved by the invention] 1. At the semiconductor integrated circuit manufacturing site, there are cylinder cavities,
There are 100 to 200 nets, and if the displacement per cylinder cabinet is 1001/min, then 1
144oo~28800m' of clean air will be discharged per day.

In order to replenish the clean air discharged outside the clean room, outside air is newly taken in, conditioned, and then supplied to the clean room, but the air conditioning costs required here are enormous.

Therefore, by exhausting the inside of the cabinet only when necessary instead of constantly exhausting it, the amount of clean air exhausted outside the clean room is reduced, the energy required to replenish lean air is omitted, and air conditioning costs are reduced. There is a desire for a cylinder cabinet that can reduce the amount of damage, and an object of the present invention is to provide such a cylinder cabinet.

2. There are also the following problems regarding the detection of gas leaks from gas piping in gas cylinders and cylinder cabinets.

In other words, as mentioned above, in the conventional cylinder cabinet, multiple gas cylinders are housed in one cylinder cabinet, but as a result, the internal volume of the cylinder cabinet has increased to a considerable value (for example, when a 10J2 gas cylinder is Accommodates 5 bottles, width 1750m
The internal volume of a cylinder cabinet with m1 height of 1600 mm and depth of 400 mm is 1120 JZ).

In a cylinder cabinet with such internal volume,
Even if a gas leak occurs, it will diffuse into the cylinder cabinet and be diluted, so even if a gas leak detector is provided in the cylinder cabinet, there will be a time delay in detecting the gas leak.

Naturally, gas leak detectors have detection sensitivities depending on each gas, and each gas has its own permissible concentration. The situation is such that it is impossible to argue whether the detection sensitivity is good or bad.

However, if a very small amount of gas leaks in an area that is below the detection sensitivity of the gas leak detector, the gas will continue to leak for a long period of time, and the gas concentration in the cylinder cabinet will eventually reach the detection sensitivity of the gas leak detector. A gas leak will be detected only when the detection sensitivity of .

In reality, the inside of the cylinder cabinet is constantly evacuated and clean air is constantly drawn in, so the leaked gas is considerably diluted, and the gas leak goes undetected for a long period of time.

In this case, if the leaking gas is a corrosive gas, the leaked gas will spread throughout the cylinder cabinet, so the gas supply piping equipment such as the gas cylinder inside the cylinder cabinet, or The gas will come into contact with various detectors, causing rust and deterioration of the resin.

Once a gas leak occurs, it is difficult to locate the gas leak and repair it, so the gas supply piping inside the cylinder cabinet must be installed properly and with equipment that is unlikely to cause gas leaks. Even so, gas leaks due to earthquakes, equipment failures, operator errors, etc. cannot be avoided.

Therefore, there is a need for a cylinder cabinet that can promptly detect gas leaks even if they occur, and the present invention provides a cylinder cabinet that can improve the safety of semiconductor manufacturing sites by realizing this. The purpose is to provide.

[Means for solving the FJ problem] The gist of the present invention is to provide a cylinder cabinet for housing at least one gas cylinder and gas supply piping equipment, in which the gas contained in the cylinder cabinet is The parts of the cylinder and gas supply piping equipment where there is a risk of gas leakage are sealed off by isolating them from other parts with appropriate members,
The cylinder cabinet is further characterized in that an exhaust line is provided at an appropriate position in the sealed part for exhausting gas leaking from the sealed part.

[Function] In the present invention, instead of constantly discharging clean air to exhaust the inside of the cylinder cabinet, the clean air is discharged only when necessary, and normal exhaust is not performed. The amount of air discharged can be reduced, energy can be saved in clean room operation, and running costs can be reduced.

In addition, by nitriding the cylinder cabinet individually (one by one) @ closed nitriding, dangerous gas leaks can be detected in a short time. pollution,
It becomes possible to minimize disasters.

[Example] Implementation of the present invention (lσ is shown below.

FIG. 1(a) is a front view showing a cylinder cabinet according to an embodiment of the present invention with the door removed, and FIG. 1(b) is a conceptual circuit diagram.

Figure 1 (a) and (b) show three wooden gas cylinders 2a and 2b.
, 2c, one of the gas cylinders 2a, 2b, and 2c is inert gas, and the other two (2b, 2c) are poisonous, corrosive, and flammable. hazardous gases (GASA).

GASB).

The gas cylinder used in this example is a recently developed gas cylinder equipped with a cylinder valve that incorporates a main valve and a purge valve, but a gas cylinder equipped with a conventional main valve cylinder valve can also be used. .

Each gas cylinder is housed in an independent cylinder cabinet 3a, 3b, 3c, and this single cylinder cabinet 3a.

3b and 3c are combined to be used as a single cylinder cabinet 1.

In this example, cylinder cabinets 3b and 3c for gas cylinders 2b and 2c containing potentially dangerous gases are partitioned into two chambers, an upper and a lower chamber, by a partition plate 20. In particular, the upper room (the part surrounded by the thick line in the diagram)
Each sealed room 4b is made so that the inside of the room is sealed (hereinafter, the upper rooms are referred to as sealed rooms 4b and 4c),
The internal volume of 4c is approximately 105J2 (width 350mm 5 height 7
50 mm and depth 400 mm (see Fig. 1(a))).

In this example, the partition plate 20 is as shown in FIG. 2(a).
I used one that could be attached and detached independently.

In addition, in addition to this, for example, there is a device that is integrated with the insertion-type lower door and is detachable together with the lower door 15b (Fig. 2 (b)).
, one that is integrated with the insertion-type upper door 15a and can be attached and detached together with the upper door 15a (Fig. 2(C)), and one that is integrated with the opening-and-closable type upper door 15a and that can be attached and detached when the upper door 15a is opened and closed (Fig. 2(C)). (d)), it is also possible to integrate it with the lower door 15b of the opening/closing type and detach it when the lower door 15b is opened/closed (FIG. 2(e)).

On the other hand, in order to completely seal the sealed chambers 4a and 4b,
In this example, a rubber backing as shown in FIG. 3(a) is formed as a sealing material 25 at the end of the partition plate 20, and the cylinder and the partition plate 20 are sealed at the outer periphery of the body of the cylinder. . By forming such a sealing material 25, even if there is a dimensional difference between the cylinders, it is possible to easily and sufficiently seal the cylinders without changing the dimensions of the partition plates. The sealing material is not limited to rubber, but may be any material that is non-flammable (or flame-retardant) and flexible; for example, a bellows made of non-flammable or flame-retardant fiber or resin. (Fig. 3 (b)), and the part to be sealed is not limited to the outer periphery of the body of the cylinder, but may also be the outer periphery of the neck of the cylinder (Fig. 3 ((ri, (d)). , an adapter 26 may be provided at the neck of the cylinder (Fig. 3(e)).
, (f)).

The upper part of the gas cylinder, the cylinder valve, and gas supply piping equipment are housed in the sealed chambers 4b and 4c. As mentioned above, these may cause gas leakage for some reason.

Further, inside the sealed chambers 4b, 4c, there are gas detectors 5b, 5c for detecting gas leakage or forced suction type gas suction ports 6b, 6c, return lowers b, 7c, and for detecting ignition. It is also equipped with fire sensors.

These sealed rooms 4b and 4c are normally kept in a sealed state and are completely isolated from the clean room. However, in the unlikely event that a gas leak occurs, the exhaust dampers 8b and 8 installed in the sealed room will be installed at the time the gas leak is detected.
By opening c, the residual gas in the sealed chamber is removed from the exhaust line 1.
As shown in FIG. 4, the air can be exhausted to the outside of the clean room via 0b and 10c. In addition, exhaust line 1
The installation position is not limited to 0b and 10c, but may be installed at the bottom of the sealed part (Fig. 5), on the back or side (Fig. 6), or on the upper side (Fig. 7), etc. is possible. The damper used here has a gap around the outer periphery of the damper (blade) even if it is set to the fully closed position as conventionally used, and exhaust air is not performed from that gap, but when it is fully closed, It must be able to be completely closed and completely isolate the exhaust lines 10b, 10c from the sealed chambers 4b, 4c.

Further, when the sealed chambers 4b and 4c are evacuated, a purge gas supply valve (AVlB) is installed so that the sealed chambers can be purged with gas at the same time.

AV 26) is provided. The purge gas supply piping may be branched and supplied outside the cylinder cabinet (FIG. 8), branched and supplied in a sealed part of the cylinder cabinet (FIG. 9), or other cases. Closed room 4b.

The gas used for purging 4C is preferably N gas, which is abundantly stored in semiconductor manufacturing plants (some of the gases used here can ignite when they come into contact with air, so air is used as the purge gas). It is better not to do so).

As described above, by housing parts with a possibility of gas leakage in a sealed room and not exhausting the sealed room except when necessary, the discharge of clean air outside the clean room is minimized. It becomes possible to suppress the

Moreover, the cylinder cabinet 2a.

2b and 2c are independent for each gas cylinder, and the air in the sealed chambers 4b and 4c can be exhausted individually, so the amount of clean air discharged can be significantly reduced compared to conventional systems. It is possible.

Furthermore, since the sealed rooms 4b and 4c are isolated from the clean room and the exhaust lines 10b and 10c, even if a gas leak occurs in these rooms, the degree to which the leaked gas is diffused and diluted is within the cylinder cabinet. Compared to conventional systems, which have a room and are constantly evacuated, this can be dramatically reduced. This means that the ability to detect gas leaks is increased. In other words, the internal volume of the sealed chambers 4b and 4c is limited (as mentioned above, the internal volume of each sealed chamber is approximately 1.05
1) The time it takes for the leaked gas to reach the gas detectors 5b and 5c installed in the room, and the gas leak detector 5
The time it takes for the concentration of the leaked gas to rise to the detection sensitivity of b and 5c is different from that of a conventional cylinder cabinet (3 wood, the internal volume is approximately 675 JL (width 1050 mm). , height 1800, depth 400), gas leakage can be detected in about 1/6 the time.

The examples shown in FIGS. 1(a) and 1(b) use a forced suction type gas leak detector to detect gas concentration. The air in the sealed chambers 4b, 4c is sucked in and returned to the sealed chambers 4b, 4c through the detectors 5b, 5c, and the air in the sealed chambers 4b, 4c is constantly circulated. In addition, suction ports 6b, 6c, return lower b,
By providing 7c below the closed chambers 4b and 4c, leakage of gas having a higher specific gravity than air can be effectively detected.

In addition to the above, the cylinder cabinet is made independent for each gas cylinder, and the parts where there is a possibility of gas leakage are housed in a sealed room, so even if a gas leakage occurs, there will be no contamination from the leaked gas. For example, if the leaked gas is a corrosive gas, in a conventional cylinder cabinet, the contamination due to the gas leak can spread to all the pipes and equipment inside the cabinet. In extreme cases, all of the equipment and piping within the cabinet will be affected by rust and material deterioration, and all parts may have to be replaced.

Although it is possible to eliminate gas leaks by, for example, using gas cylinders, gas supply piping, and equipment with parts or installation methods that have less external leakage, it is still impossible to completely eliminate gas leaks. It is. In other words, it is not enough to just seal the cylinder cabinet; it is necessary to provide an exhaust line in the cylinder cabinet, as it is not possible to avoid the effects of earthquakes, gas leaks due to equipment lifespan or damage, or gas leaks due to incorrect operation. These functions are necessary for safety management and cannot be eliminated.Also, it is desirable to install a gas leak detector to detect gas leaks as soon as possible.

As a gas leak detector, either a diffusion type or a forced suction type can be used; in the former case, install it in a sealed area (Fig. 10); in the latter case, install it in a closed area (Figure 10); in the latter case, install it in a closed area The gas leak detector can be connected to the return port and the suction port.The gas leak detector can be installed at the bottom of the sealed part (Fig. 11) or on the side (Fig. 12). ) or on the top plate (Fig. 13).

(Modification 1) FIG. 14 shows a modification of the above embodiment.

In the above embodiment, individual cylinder cabinets corresponding to the number of gas cylinders were combined into a single cylinder cabinet, but in this modification, the cylinder cabinets are individualized. This is an example of an integrated cylinder cabinet in which the entire upper part of the cylinder head of a gas cylinder is sealed.

(Modification 2) FIG. 15 shows another modification.

In the above modification, an example was shown in which the entire upper part of the cylinder head of the gas cylinder was sealed, but in this modification, only the upper vicinity of the cylinder head of the gas cylinder is sealed. In this way, by limiting the area to be sealed only to areas where there is a risk of gas leakage, the volume of the sealed area becomes smaller, making it possible to further reduce the amount of clean air discharged, and also improving the ability to detect leaking gas. can be further enhanced.

[Effects of the Invention] The following effects can be obtained by providing individual sealed chambers in the cylinder cabinet and not exhausting air except when necessary.

1. Clean air emissions associated with exhaust can be reduced.

2. The ability to detect gas leaks is improved.

3. The spread of contamination due to gas leakage can be minimized.

[Brief explanation of the drawing]

FIG. 1(a) is a front view showing a cylinder cabinet according to an embodiment of the present invention, and FIG. 1(b) is a conceptual diagram of its circuit. FIGS. 2(a) to 2(e) are perspective views showing the partition plate. FIGS. 3(a) to 3(f) are a plan view and a sectional view showing the sealing material. FIG. 4 is a conceptual diagram showing the exhaust system. 5 to 7 are conceptual diagrams showing the wiring position of the exhaust line. FIGS. 8 and 9 are conceptual diagrams showing the wiring positions of the purge gas supply piping. Figure 10~
FIG. 13 is a conceptual diagram showing the installation position of the gas leak detector. FIGS. 14 and 15 are conceptual diagrams showing modified examples. FIG. 16 is a perspective view showing a conventional example. (Explanation of symbols) 1... Cylinder cabinet, 2a, 2b. 2C... Gas cylinder 3a, 3b, 3c... Individual cylinder cabinet, 4b, 4c... Sealed room,
5b, 5c... Gas detector, 6b, 6c... Suction port, 7b, 7c... Return port, 8b, 8c... Exhaust damper 10b, 10c''-Exhaust line, 15.15a,
15b...Cover (door, panel), 25...Sealing material, 26...Adapter No. ``Figure (0) b C Figure (e) Figure (d) Section 1 rotation Figure 1゜Figure Figure Figure Figure

Claims (1)

[Claims] In a cylinder cabinet for housing at least one or more gas cylinders and gas supply piping equipment, a portion where gas leakage may occur from the gas cylinder and gas supply piping equipment stored inside the cylinder cabinet. The part is hermetically sealed by isolating it from other parts with an appropriate member, and an exhaust line is provided at an appropriate position in the sealed part to exhaust leakage gas from the sealed part. A cylinder cabinet characterized by: