WO1998048215A1

WO1998048215A1 - Gas supply facility

Info

Publication number: WO1998048215A1
Application number: PCT/JP1998/001856
Authority: WO
Inventors: Kazuo Yokogi
Original assignee: Air Liquide Japan, Ltd.
Priority date: 1997-04-22
Filing date: 1998-04-22
Publication date: 1998-10-29
Also published as: AU7079598A; JP2002511133A

Abstract

It is intended to provide a gas supply facility which can cope with the manufacture of semiconductor-integrated devices having a higher degree of integration and can improve the working efficiency. According to the present invention, a gas supply facility which comprises: a gas container (7); a gas consumption unit (3) of consuming a gas stored in said gas container; a gas supply line (8) for supplying said gas from said gas container to said gas consumption unit; a purge gas supply source for supplying a purge gas to said gas supply line; and an exhaust gas treatment unit (10) connected to the upperstream portion of said gas supply line adjacent to said gas container, for treating an exhaust gas discharged from said upperstream portion of said gas supply line by the purge gas from said purge gas supply source, is characterized by further comprising: a feedback vent line (13) capable of being opened and closed, in which one end thereof is connected to the downstream portion of said gas supply line adjacent to said gas consumption unit and the other end thereof is connected to said exhaust gas treatment unit; and a valve (V1) provided on said gas supply line between said feedback vent line and said gas consumption unit.

Description

D E S C R I P T I O N

GAS SUPPLY FACILITY

Technical Field

The present invention relates to a gas supply facility for supplying a feed gas, for example, for use in the manufacture of semiconductor devices.

Background Art

In the recent years, the degree of integration of semiconductor integrated circuits such as IC develops a tendency of increasing more and more. It has become possible not only to manufacture semiconductor integrated circuits having a degree of integration of 4 Mbit ~ 64 Mbit, but also to manufacture semiconductor integrated circuits having a higher degree of integration of 256 Mbit. In order to manufacture semiconductor integrated circuits having such a higher degree of integration, it is required that a feed gas for use in the manufacture of semiconductor integrated circuits has a higher purity.

A gas supply facility for use in the manufacture of semiconductor integrated circuits is hitherto installed in a semiconductor-manufacturing factory, and comprises a gas container installed in a gas supply room in the semiconductor-manufacturing factory, which stores u feed gas, and a gas supply line extending from said gas container. The gas container is generally accommodated for use in a cylinder cabinet because a feed gas such as silane is dangerous. The gas supply line is connected to a semiconductor- manufacturing unit installed in a clean room which is at a place alienated from the gas supply room, so as to supply a feed gas from the gas container into the semiconductor-manufacturing unit in the manufacture of semiconductors.

In such a gas supply facility, a gas supply room has usually a plurality of cylinder cabinets and each of the cylinder cabinets accommodates a gas container. These gas containers store feed gases different in kind, respectively. After a certain kind of feed gas has been used, the same feed gas is therefore remaining in a gas supply line. In order that the purity of a feed gas for next use will be prevented from being lowered by this remaining feed gas, it is designed that a purge gas consisting of an inert gas such as nitrogen gas is introduced into the gas supply line. Furthermore, in order to treat an exhaust gas based on this purge gas, an exhaust gas treatment unit is usually installed in the gas supply room and in the clean room, respectively.

By the way, a purge gas is continuously introduced into the gas supply line also when completed semiconductor devices are taken out of a semiconductor-manufacturing unit. The reason for effecting this operation is that the continuous supply of the purge gas makes the inside of the semiconductor-manufacturing unit positive in pressure, thereby restraining particles in the open air from invading into the semiconductor-manufacturing unit which is opened. Also when parts such as flow rate regulators attached on the wall of the gas supply line in the clean room are exchanged, furthermore, a purge gas is introduced into the gas supply line and this purge gas is passed through the semiconductor-manufacturing unit and released to the atmosphere by way of the exhaust gas treatment unit in the clean room.

Further, it is not preferred that a poisonous feed gas is permitted to remain in the gas supply line, in a case where a semiconductor-manufacturing factory is not operated for a long period of time. For coping with such a state that the factory is not operated for a long period of time, therefore, the introduction of a purge gas in the gas supply line may be effected. In this case, it is necessary to substitute the feed gas with the purge gas throughout the whole of the gas supply line. Thus, the substituting work of the feed gas with a purge gas is effected by introducing the purge gas from the upperstream side of the gas supply line, causing this purge gas to pass through the semiconductor-manufacturing unit, and then releasing the purge gas to the atmosphere by way of the exhaust gas treatment unit on the side of the clean room.

In order that a semiconductor-manufacturing unit is not contaminated by the open air when parts such as flow rate regulators attached on the gas supply lino in the clean room are exchanged, in addition, it is also conceived that a purge gas is branched from the downstream side of the gas supply line and an exhaust gas is treated in another exhaust gas treatment unit installed inside the clean room by use of said purge gas. However, the aforementioned gas supply facility has such problems as described below, in a case where a purge gas is introduced in the gas supply line.

At the first, a portion of the gas supply line gets communicated with the open air when parts such as flow rate regulators in a clean room are exchanged, and hence there is such a possibility that even when a purge gas is caused to flow here, there is such a possibility that particles in the open air are mixed in the gas supply line so that the inside of a semiconductor-manufacturing unit positioned downstream of the flow rate regulators is contaminated therewith. In such case, the purity of the feed gas in the semiconductor-manufacturing unit may be lowered, with a fear that it is made difficult to manufacture semiconductor devices having a higher degree of integration of 256 Mbit ~ 4 Gbit which will be required in future.

When a purge gas is supplied to the gas supply line, for coping with such a state that a semiconductor-manufacturing factory is not operated for a long period of time, at the second, workers in the gas supply room and workers in the clean room must perform the works, with keeping in contact with each other, because the gas supply room and the clean room are at positions alienated from each other. Namely, it can not be always said that the working efficiency is good.

Furthermore, in a case where it is designed that when parts such as flow rate regulators attached on the gas supply line in the clean room are exchanged, a purge gas is branched from the downstream side of the gas supply line and an exhaust gas is treated in another exhaust gas treatment unit installed inside the clean room by use of said purge gas, there are caused such problems that not only a space in the clean room is occupied therewith, but also a considerable cost is required for installing more the exhaust gas treatment unit.

Due to consideration of the aforementioned facts, the present invention has been achieved and it is intended to provide a gas supply facility which can cope with the manufacture of semiconductor devices having a higher degree of integration and can improve the working efficiency.

Disclosure of Invention

In order to achieve the aforementioned purposes, an invention according to claim 1 resides in^ a gas supply facility comprising- a gas container", a gas consumption unit of consuming a gas stored in said gas container^*, a gas supply lino for supplying said gas from said gas container to said gas consumption unit; a purge gas supply source for supplying a purge gas', a purge gas introduction line, in which one end thereof is connected to said purge gas supply source and the other end thereof is connected to a predetermined position of said gas supply line', and an exhaust gas treatment unit connected to the upperstream portion of said gas supply line adjacent to said gas container, for treating an exhaust gas discharged from said upperstream portion of said gas supply line by the purge gas from said purge gas supply source, characterized by further comprising^" a feedback vent line capable of being opened and closed, in which one end thereof is connected to the downstream portion of said gas supply line adjacent to said gas consumption unit and the other end thereof is connected to said exhaust gas treatment unit! and a valve provided on said gas supply line between said feedback vent line and said gas consumption unit.

If a purge gas is introduced from a purge gas supply source to a gas supply line and a valve is caused to assume a closed stated, according to this gas supply facility, it will become possible that the purge gas is passed through a feedback vent line , not passed through a gas consumption unit such as a semiconductor-manufacturing unit, and treated in an exhaust gas treatment unit in the vicinity of a gas container. For instance, if parts such as flow rate regulators need to be exchanged have been provided upperstream of a point where the feedback vent line and the gas supply line are connected with each other, the purge gas is prevented from flowing into the gas consumption unit in exchange of the same parts.

If a purge gas is introduced from the upperstream side of the gas supply line by use of a purge gas supply source and a valve is closed when the purge gas is supplied to the gas supply line, for coping with such a state that a semiconductor-manufacturing factory is not operated for a long period of time, it will become possible that the substituting work of a feed gas with a purge gas throughout the whole of the gas supply line is carried out and at the same time the purge gas is caused to flow through the exhaust gas treatment unit through the feedback vent line. In this case, it is possible for workers to perform the work on the upperstream side of the gas supply line, or in the vicinity of the gas container and exhaust gas treatment unit.

If a valve is closed when the supply of a liquefied gas is stopped in a case where a liquefied gas is used as a feed gas, furthermore, it will become possible that the feed gas is expanded by the volume of a feedback vent line so that its pressure is reduced and the liquefied gas in a state of a saturation vapor pressure is transferred to a state of non-saturation vapor pressure. As a result, the liquefied gas which has been once evaporated becomes difficult to be liquefied again in the gas supply lino.

Further, an invention according to claim 2 resides in: a gas supply facility comprising: a gas container; a gas consumption unit of consuming a gas stored in said gas container; a gas supply line for supplying said gas from said gas container to said gas consumption unit; a purge gas supply source for supplying a purge gas! a purge gas introduction line, in which one end thereof is connected to said purge gas supply source and the other end thereof is connected to a predetermined position of said gas supply line! and an exhaust gas treatment unit connected to the upperstream portion of said gas supply line adjacent to said gas container, for treating an exhaust gas discharged from said upperstream portion of said gas supply line by the purge gas from said purge gas supply source, characterized by further comprising; a vent line capable of being opened and closed, in which one end thereof is connected to said purge gas introduction line and the other end is connected to said exhaust gas treatment unit; and a valve provided on said purge gas introduction line between said vent line and said purge gas supply source.

Also in this construction, it will become possible that a mixed gas consisting of a remaining gas in the gas supply line and a purge gas is treated in an exhaust gas treatment unit in the vicinity of the gas container.

Brief Description of Drawings

Fig. 1 is a rough view showing the first embodiment of the a9 supply facility according to the present invention; and

Fig. 2 is a rough view showing the second embodiment of the gas supply facility according to the present invention. Best Mode of Carrying Out the Invention

Now referring to the drawings, a preferred embodiment of the gas supply facility according to the present invention will be described in detail. In the drawings, in addition, the same reference numeral will be given to the same or corresponding part.

Fig. 1 is a rough view showing one embodiment of the gas supply facility according to the present invention which is applied to a semiconductor-manufacturing factory. As shown in the same drawing, a clean room 1, in which the cleanliness of air is enhanced, is provided in the semiconductor-manufacturing factory. Inside of the clean room

1 are installed a plurality of gas control boxes 2, (only three boxes are depicted in the illustrated embodiment). Each of the gas control boxes 2 is installed just near to or inside of a semiconductor- manufacturing unit (gas consumption facility) 3. These semiconductor- manufacturing units 3 are constructed such that workers can perform the taking-out of completed semiconductor devices or other operations. To each of the semiconductor-manufacturing units 3 is connected an exhaust gas treatment unit 4 for treating an exhaust gas cooing out of the same semiconductor-manufacturing unit 3. These exhaust gas treatment units 4 can also treat (render harmless) a residual feed gas which has been sent from respective cylinder cabinets 6A, 6B and 6C, described hereinafter, and used in the semiconductor-manufacturing units 3. A gas supply facility of this embodiment for supplying feed gases to such semiconductor-manufacturing units 3 has a¹ gas supply room 5. In this gas supply room 5, there are installed a plurality of cylinder cabinets 6A, 6B and 6C, (only three cabinets are depicted in the illustrated embodiment), for supplying feed gases necessary for manufacture of semiconductor devices to the semiconductor- manufacturing units 3. In the inside of each of the cylinder cabinets 6A, 6B and 6C, a cylinder (gas container) 7 is accommodated, where feed gases different In kind are stored in the respective cylinders 7. Harmful gas such as silane, phosphine or hydrogen bromide is used as the feed gas. In addition, the cylinder cabinets 6A, 6B and 6C have usually the same construction, and hence only the cylinder cabinet 6A will be described hereinafter.

From the cylinder 7 in the cylinder cabinet 6A is extended a main supply line 8a of a gas supply line 8, and to this main supply line 8a is connected a purge gas introduction line 9. Further, to this main supply line 8a is connected also another end of a vent line 11 in which one end thereof is connected to an exhaust gas treatment unit 10 disposed inside the gas supply room 5. If a proper valve operation is therefore carried out when a purge gas consisting of an inert gas such as nitrogen gas is introduced from a purge gas supply source (not shown) through the purge gas introduction line 9, a feed gas remaining in the main supply line 8a of the gas supply line 8 will be entrained with the purge gas so as to be sent into the exhaust gas treatment unit 10 through the vent line 11.

Further, the main supply line 8a of the gas supply line 8 is branched, in a branch box 12 installed outside the gas supply room 5, to three branch supply lines 8b in accordance with the number of the gas control boxes 2, where the end of the respective branch supply lines 8b runs through the clean room 1 and it is connected to each of the semiconductor-manufacturing units 3 via the three gas control boxes 2. Inside the branch box 12, furthermore, there is provided a purge gas introduction line 16 which is branched on its way to three lines. Each branch supply line 8b branched from the main supply line 8a has a valve V6 attached on its base. On the other hand, also each of the three branch introduction lines 16a branched from the purge gas introduction line 16 has a valve V6 attached on its fore end. It is enabled by properly operating these valves Y5 and V6 to introduce a purge gas from a purge gas supply source (not shown) outside the branch box 12 to the respective branch supply lines 8b through the purge gas introduction line 16.

At the end of the respective branch supply lines 8b, a feedback vent line 13 extends from a position upperstream of a valve Yl attached in the gas control box 2. From the standpoint of causing a purge gas to pass throughout the whole of the gas supply- line 8, it is preferred that a position where the feedback vent line 13 and the branch supply line 8b are connected with each other is determined near by the semiconductor-manufacturing unit as much as possible. At one end of each feedback vent line 13, valve V2 is attached in the vicinity of a position where the same one end of each feedback vent line 13 and each branch supply line 8b are connected with each other, and the other end of each feedback vent line 13 is connected to the exhaust gas treatment unit 10 in the gas supply room 5. The exhaust gas treatment unit 10 is being sucked by a vacuum evacuation apparatus 21. On each feedback vent line 13 in the gas supply room 5 is attached an analysis apparatus (not shown) capable of measuring the concentration of a feed gas in an order of ppt, and it is possible to monitor the substituting work of the feed gas with a purge gas, on the basis of a value of the feed gas concentration detected by this analysis apparatus. On each branch supply line 8b in each gas control box 2, a flow rate regulator 14 (for example a pressure reducing valve or mass flow meter) is attached upperstream of a position where the feedback vent line 13 is connected thereto, and a valve V3 is attached upperstream thereof. To a position between this valve V3 and the flow rate regulator 14 is connected each of three branch introduction lines 15a which are branched from the way of a purge gas introduction line 15, and on each branch introduction line 15a is attached a valve V4, It is enabled by properly operating these valves Y3 and Y4 to introduce a purge gas to the respective semiconductor-manufacturing units 3 through the purge gas introduction line 15.

Also in the other two cylinder cabinets 6B and 6C, although not illustrated in detail, there is provided a gas supply line which is branched on its way to three lines. Each branch supply line of the respective gas supply lines is connected to a semiconductor- manufacturing unit 3 via each gas control box 2 in the clean room 1.

If a purge gas is introduced into the branch supply line 8b of the gas supply line 8, as the valves Yl and V3 are caused to assume a closed state and the valves V2 and V4 are caused to assume an open state, in a case where parts such as flow rate regulator 14 are exchanged in the gas control boxes 2 in a gas supply facility having such a construction as mentioned above, it is destined that this purge gas is passed through the feedback vent line 13, not passed through the semiconductor-manufacturing unit 3, ant treated in the exhaust gas treatment unit 10 in the gas supply room 5. Accordingly, the semiconductor-manufacturing unit 3 is not contaminated by the open air when parts are exchanged, whereby the purity of a feed gas in the manufacture of semiconductors can be improved. Namely, this gas supply facility can cope with the manufacture of semiconductor devices having such a higher degree of integration that is required in future.

If a purge gas is introduced from the upperstream side bf the gas supply line 8 , this is from the side of the gas supply line 8 of the gas supply room 5, when the purge gas is supplied to the gas supply line 8, for coping with such a state that a semiconductor- manufacturing factory is not operated for a long period of time, it will become possible, only by causing the valves V2, V3 and V5 to assume an opened state and causing the valves VI, V4 and V6 to assume a closed state, that the substituting work of a feed gas with a purge gas throughout almost the whole of the gas supply line 8 is carried out and at the same time the purge gas is passed unidirectionally through each feedback vent line 13 so as to be vacuum-evacuated by the vacuum evacuation apparatus 21 in the gas supply room 5. Accordingly, it is possible for workers to perform the substituting work of a purge gas, based on an unidirectional flushing purge method having a highest purge efficiency, without operating the semiconductor-manufacturing unit 3, whereby the efficiency of the substituting work by a purge gas can be remarkably improved, the feed gas in the gas supply line 8 can be removed within a short period of time and it can be therefore designed to lower the cost. Since the gas supply facility is furthermore designed such that each exhaust gas treatment unit 10 in the gas supply room 5 can be effectively utilized, it is not expensive, as compared with a case where another new exhaust gas treatment unit is installed respectively for each gas control box 2 in the clean room 1. Further, it becomes unnecessary to install another new exhaust gas treatment unit respectively for each gas control box 2 in the clean room 1. Accordingly, a space in the clean room 1 can be saved.

By properly causing the valve V2 to assume an opened state when the supply of a feed gas is stopped, in a case where a liquefied gas such as boron trichloride (BCI3) or dichlorosilane

is used as the feed gas, the feed gas in the gas supply line 8 is expanded to each feedback vent line 13, whereby it is reduced in pressure and transferred from a state of a saturation vapor pressure to a state of non-saturation vapor pressure. Even if the gas supply line 8 is somewhat cooled down by the open air, accordingly, the feed gas becomes difficult to be liquefied, and as a result, the metal contamination caused by the liquefaction of the feed gas in the gas supply line can be prevented.

In addition, the present invention is not limited to the aforementioned embodiment. In the aforementioned embodiment, for example, the feedback vent line 13 is made to extend from the branch supply line 8b in the gas control box 2, and connected to the exhaust gas treatment unit 10 on the side of the cylinder cabinet 6. However, the feedback Yent line 13 may be made to extend from the branch supply line 8b which. is outside the gas control box 2. Furthermore, it is a matter of course that the gas supply facility according to the present invention is applicable to a semiconductor-manufacturing unit having no gas control box 2, and further applicable to a gas consumption unit other than the semiconductor-manufacturing unit, for example a unit of manufacturing micro devices such as plasma generators or liquid crystal devices

Fig. 2 shows a second embodiment of the gas supply facility according to the present invention. This embodiment has a construction that is substantially equal to that of the embodiment shown in Fig. 1, except that there is not provided the feedback vent line 13 and a vent line 20 is alternately provided in which one end thereof is connected to the way of the purge gas introduction line 16 and the other end thereof is connected to the exhaust gas treatment unit 10 in the gas supply room 5. In the construction of Fig. 2, furthermore, the purge gas introduction line 16 has a valve V7 provided at a proper position upperstream of a position where it is connected to the vent line 20. The vent line 20 has also a valve Y8.

For instance, in a case where a feed gas in the gas supply line 8b between the valve V5 and the valve VI is substituted with a purge gas, in such a construction as mentioned above, the valves Yl, V4, V5 and V8 are closed and the valves V3, V6 and V7 are opened. Then, the purge gas is introduced into the gas supply line 8b by way of the purge gas introduction line 16. If the valve Y7 is thereafter closed and the valve V8 is opened, a mixed gas consisting of the purge gas and feed gas in the gas supply line 8b is caused to flow back through the purge gas introduction line 16, and sent to the exhaust gas treatment unit 10 through the vent line 20. At that time, the exhaust gas treatment unit 10 is made negative in pressure at a value that is lower than the pressure of the gas supply line 8 by means of the vacuum evacuation apparatus 21, and hence the mixed gas in the gas supply line 8 is permitted to flow into the exhaust gas treatment unit 10 depending on a pressure difference. By repeating this work several times, the concentration of the feed gas in the gas supply line 8 gets lower than a desired value. Thus, the gas substituting work is completed.

Even if parts Buch as the flow rate regulators 14 are exchanged after the completion of this work, the semiconductor-manufacturing unit 3 is not opened to the open air. Accordingly, the inside of the semiconductor-manufacturing unit 3 is prevented from being contaminated, as in the prior art.

In this second embodiment, by the way, one vent line is provided for causing an exhaust gas to flow to the exhaust gas treatment unit 10. It should be therefore noticed that the second embodiment is, simplified in the facility construction, as compared with the embodiment shown in Fig. 1 where the feedback vent lines 13 are required in a number corresponding to the number of the semiconductor-manufacturing units 3.

Industrial Applicability In a case where a gas remaining in the gas supply line is expelled by a purge gas, according to the present invention, as described above, it becomes possible that the purge gas is caused to bypass a gas consumption unit such as a semiconductor-manufacturing unit, and treated in an exhaust gas treatment unit provided upperstream of the same gas consumption unit, while it is hitherto passed through the gas consumption unit.

Even when parts provided in the gas supply line are exchanged, a purge gas contacted with the open air is, therefore, no introduced into the gas consumption unit. This is effective especially in a case where the gas consumption unit is of a semiconductor-manufacturing unit which is apt to be easily contaminated by particles. Accordingly, the gas supply facility can cope with the manufacture of semiconductor devices having such a higher degree of integration that is required in future.

When a purge gas is introduced into the gas supply line, it becomes possible to perform the substituting work near the gas container or near the exhaust gas treatment unit in the vicinity thereof. Accordingly, the efficiency of the substituting work by a purge gas can be remarkably improved, the feed gas in the gas supply 19

line can be removed within a short period of time, and the cost can be therefore restrained.

When the supply of a liquefied gas is stopped in a case where the liquefied gas is used as a gas to be stored in a gas container, the said gas becomes difficult .to be liquefied even if the gas supply line is somewhat cooled down by the open air. As a result, the metal contamination caused by the liquefaction of said gas in the gas supply line can be prevented.

When the gas supply facility according to the present invention is built up, furthermore, the working days for the cleaning of the inside of units or the inside of pipes, which is necessary in starting up the operation of the same gas supply facility, can be remarkably shortened.

Claims

C L A I M S

1. A gas supply facility comprising: a gas container^", a gas consumption unit of consuming a gas stored in said gas container; a gas supply line for supplying said gas from said gas container to said gas consumption unit; a purge gas supply source for supplying a purge gas; a purge gas introduction line, in which one end thereof is connected to said purge gas supply source and the other end thereof is connected to a predetermined position of said gas supply line; and an exhaust gas treatment unit connected to the upperstream portion of said gas supply line adjacent to said gas container, for treating an exhaust gas discharged from said upperstream portion of said gas supply line by the purge gas from said purge gas supply source, characterized by further comprising: a feedback vent line capable of being opened and closed, in which one end thereof is connected to the downstream portion of said gas supply line adjacent to said gas consumption unit and the other end thereof is connected to said exhaust gas treatment unit; and a valve provided on said gas supply line between said feedback vent line and said gas consumption unit.

2. A gas supply facility comprising: a gas container", a gas consumption unit of consuming a gas stored in said gas container', a gas supply line for supplying said gas from said gas container to said gas consumption unit', a purge gas supply source for supplying a purge gasJ a purge gas introduction line, in which one end thereof is connected to said purge gas supply source and the other end thereof is connected to a predetermined position of said gas supply line', and an exhaust gas treatment unit connected to the upperstream portion of said gas supply line adjacent to said gas container, for treating an exhaust gas discharged from said upperstream portion of said gas supply line by the purge gas from said purge gas supply source, characterized by further comprising: a Y╬▓nt line capable of being opened and closed, in which one end thereof is connected to said purge gas introduction line and the other end is connected to said exhaust gas treatment unit", and a valve provided on said purge gas introduction line between said vent line and said purge gas supply source.

3. A gas supply facility according to claim 1 or 2, in which said gas consumption unit is a semiconductor-manufacturing unit.