Enclosure system including wire mesh and thin non-porous membrane panels

Abstract

An enclosure system may be formed of a lightweight panel with a thin non-porous membrane that enables the extraction and leak detection of hazardous gases from housing equipment such as vacuum pumps, valves, abatement equipment and the like. Additionally, the enclosure system includes a one or multiple layers of wire mesh which prevent projectiles with a high kinetic energy from escaping from the housing equipment thereby minimising the risk of an explosion causing parts or panels to be ejected from the enclosure system.

Claims

1. An enclosure for minimising egress of hazardous gases released from post process chamber equipment during operation thereof, the enclosure comprising: a structural frame describing an outer envelope of post process chamber equipment to be housed therein; an outlet configured to be connected to an extraction system; and a plurality of panels, each panel of the plurality of panels comprising a respective sub-frame to which is connected a respective mesh layer in combination with a respective non-porous membrane layer, the respective mesh and respective non-porous membrane layers of each panel being substantially co-planar with one another, wherein the plurality of panels are mounted to the structural frame in a contiguous manner such that, in use, a pressure internal to the enclosure, lower than that experienced external to the enclosure, can be maintained thereby inhibiting inadvertent egress of any hazardous gases present in the enclosure.

2. The enclosure according to claim 1, wherein one or more panels of the plurality of panels are removably mounted to the structural frame.

3. The enclosure according to claim 1, wherein the respective non-porous membrane layers comprise a rubber or a polymer.

4. The enclosure according to claim 1, wherein the respective non-porous membrane layers are configured to rupture upon catastrophic failure of equipment housed within the enclosure.

5. The enclosure according to claim 4, wherein the thickness of the respective non-porous membrane layers is in the range of 0.05 to 0.5 mm.

6. The enclosure according to claim 5, wherein the thickness of the respective non-porous membrane layers is in the range of 0.05 to 0.1 mm.

7. The enclosure according to claim 1, wherein the respective non-porous membrane layers are configured to flap out of plane upon catastrophic failure of equipment housed within the enclosure.

8. The enclosure according to claim 1, wherein the thickness of the respective non-porous membrane layers is in the range of 0.5 to 3 mm.

9. The enclosure according to claim 1, wherein the thickness of the respective non-porous membrane layers is in the range of 1 to 2 mm.

10. The enclosure according to claim 8, wherein the respective mesh layers are configured to contain projectiles formed upon catastrophic failure of equipment housed within the enclosure.

11. The enclosure according to claim 8, wherein the respective non-porous mesh layers each comprise two sheets of wire mesh.

12. The enclosure according to claim 1, wherein the respective non-porous membrane layers are each provided between the two sheets of wire mesh.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order that the present disclosure may be well understood, an embodiment thereof, which is given by way of example only, will now be described with reference to the accompanying drawing.

(2) FIG. 1 illustrates a schematic representation of an enclosure according to the present disclosure.

(3) FIG. 2 illustrates a first panel that may be used to form the enclosure of the present disclosure.

(4) FIG. 3 illustrates a second panel that may be used to form the enclosure of the present disclosure.

(5) FIG. 4 illustrates a third panel that may be used to form the enclosure of the present disclosure.

(6) FIG. 5 illustrates a fourth panel that may be used to form the enclosure of the present disclosure.

(7) FIG. 6 illustrates the side view of the fourth panel illustrated in FIG. 5.

DETAILED DESCRIPTION

(8) FIG. 1 illustrates an enclosure system 2 according to the present disclosure. The enclosure system 2 is configured to encompass one or more pieces of equipment. The equipment represents a collection of apparatus located downstream of a semiconductor processing chamber that, in operation, receives harsh process gases therefrom. The process gases include unused precursor gases and by-products formed during the processing within the chamber. In this example, the post-chamber equipment 4, comprises a vacuum pump 6 connected to an abatement unit 8 via a conduit 10. One or more valves (not shown) would also be incorporated into the equipment 4. The equipment is in fluid communication with a process chamber, for example an epitaxial chamber (not shown) via a further conduit or foreline (not shown).

(9) The enclosure system 2 comprises a metal frame 12 configured to describe an outer envelope of a working space surrounding the post-chamber equipment 4. A number of panels 14 are affixed to the frame 12 to form walls and a ceiling of the enclosure system 2. One or more of the panels 14 may be removably connected to the frame 12 or they may be configured to be connected using a hinge, or similar mechanism, to form doors. Thus, access points into the enclosure system 2, and therefore any equipment therein, by service personnel may be provided. Such access may be effected either by opening the doors and/or completely removing the, or each, respective panel from the enclosure.

(10) FIG. 2 illustrates one embodiment of a panel 14a which may be used to form the walls of the enclosure system 2. Panel 14a is a three-layer panel and comprises a thin, non-porous membrane 16a sandwiched in between two, similarly sized, wire mesh panels 18a and 18b. A first wire mesh panel 18a, a base panel, is provided with an external structural framework 20a extending around the perimeter of the mesh panel 18a, to provide structural integrity thereto. The mesh 18a may be secured to the framework 20a by conventional means for example by welding or bonding. When installed, the panels 14 are placed in a contiguous manner on the frame 12 of the enclosure 2. The panels 14 are then secured to the frame 12 to hold them in place. Each panel 14 may be secured to the frame 12 at each corner and/or along edges of the panel 14. Means for securing each panel 14 to the frame 12, may comprise permanent fixings such as bolts or hinges. If hinges are used, then the opposing side of the panel is secured using a latch or locking mechanism to retain the panel 14 in a closed configuration during operation of the vacuum and/or abatement system. Alternatively, impermanent fixings such as straps may be implemented.

(11) An alternatively configured panel 14b is illustrated in FIG. 3. In this embodiment, a mesh panel 18a is provided as the base panel, having an external structural framework 20a. A thin, non-porous membrane 16a is overlaid on the mesh panel 18a and secured thereto via the framework 20a, alternatively, the membrane 16a may be bonded directly to a mesh sheet of the mesh panel 18a.

(12) In a further alternative, as illustrated in FIG. 4, it may be that the membrane 16b of panel 14c is secured e.g. by bonding to the panel framework 20a to form a base panel and then a mesh panel 18b is secured thereto.

(13) Upon installation, panels 14b and 14c may be orientated such that the membrane 16 forms an internal surface of the enclosure 2 with the mesh 18 representing the external surface or the membrane 16 may be the external surface with the mesh 18 forming an internal surface.

(14) Each mesh panel 18 may comprise a single sheet of wire mesh or it may comprise a number of sheets of wire mesh in combination. Preferably, two wire mesh sheets are provided in each panel 14, either using the configuration illustrated in FIG. 2 or by providing two mesh sheets in the mesh panel 18a in the embodiment shown in FIG. 3 or in the mesh panel 18b in the embodiment shown in FIG. 4.

(15) The membrane material may comprise a rubber (for example from the group of neoprene, butyl and nitrile) or it may comprise a polymer (for example from the group of PVC, PET, PTFE, PE), however, any thin, frangible, non-porous material may be used. The membrane or film used in panels 14a, 14b, 14c would have a thickness in the range of 0.05 to 0.5 mm, more preferably in the range of 0.05 to 0.1 mm.

(16) An alternatively configured panel 14d is illustrated in FIGS. 5 and 6. A base panel 18c, in this instance formed of a mesh layer surrounded and supported by a structural framework 20b. Members of the structural framework 20b extend not only around the perimeter of panel 14d but also form intermediate cross bracing members 22 to sub-divide the panel into multiple sections. These members 22 allow for an alternate fixing locations to which the membrane/film can be connected. In this embodiment, a plurality of membrane sheets 26 can be provided, in contrast to the aforementioned single film 16 in earlier embodiments. As illustrated in FIG. 6, each membrane sheet 26 is fixed to the structural framework 20b along a single edge only, at a cross-bracing member 22. Each membrane sheet 26 may be secured to a respective member 22 by bonding or by clamping the sheet between the member and a securing bar or plate (not illustrated). The securing bar may be held in place by riveting or bolting through the bar to the bracing member 22. The remaining edges of the membrane sheet are left unsecured but do lie substantially co-planar to the mesh 18c of the panel 14d. As is readily apparent, the mesh 18c of this configuration may be provided in a single sheet across the width and height of framework 20b or it may, too, be provided in sections, secured at members 22. Upon installation, the panel 14d would be oriented such that the membrane sheets 26 are positioned on the outside of the enclosure 2 to represent the external surface thereof. The membrane sheets 26 differ from the earlier mentioned membranes 16a, 16b in that their thickness is somewhat increased to minimize distortion thereof such that coverage of the panel 14d is maintained. The thickness of membrane sheets 26 may be in the range of 0.5 to 3 mm, more preferably in the range of 1 mm to 2 mm.

(17) Returning to FIG. 1, the enclosure system 2 further comprises an outlet 30, through which the atmosphere within the enclosure may be drawn/extracted to replenish the air surrounding the vacuum and/or abatement system 4 during operation. Extraction means (not shown) are provided in fluid communication with the outlet 30. Said extraction means may comprise sensor means configured to detect any process fluids that ought not to be present in the atmosphere of the enclosure during operation of the vacuum and/or abatement system 4. If such process fluids are detected by sensor means within the extraction means, this is indicative of a leak in the vacuum and/or abatement system 4. Detection of such a leak results in an alert signal being created and, consequently, steps can be taken to mitigate the fault, either by immediately shutting down the apparatus or by scheduling maintenance at an appropriate time. The mitigation steps implemented are likely to be dependent on the perceived severity of the leak.

(18) Continuous extraction during operation is necessary as a safety precaution to prevent any leaked hazardous process fluids from contaminating the atmosphere outside the enclosure where personnel are located. The rate of extraction from the enclosure 2 is typically in the order of 4 to 5 air changes per minute.

(19) The configuration of the enclosure system 2 must be such to enable extraction to occur. In other words, whilst the panels 14 need not be hermetically sealed to one another via the frame 12, a sufficient level of sealing must be achieved to prevent/inhibit ingress of air so that a pressure differential (of a few, say 2 to 20 mbar) between the interior and the exterior of the enclosure can be maintained. Thereby the enclosure system 2 retains any hazardous gases in the vicinity of the vacuum and/or abatement system 4 and the volume of the enclosure is safely extracted via an extraction duct connected to outlet 30.

(20) If a failure event is experienced, whereby material deposited within the equipment 4 becomes explosive, two primary effects will be realised. Fragments of the body of the apparatus will be formed as the catastrophic failure occurs. These fragments will form high velocity projectiles, capable of wreaking serious damage upon proximate equipment. The second aspect of the explosive incident will be a significant high pressure disturbance which, if contained, can also cause a great deal of damage to structural components in the area. Indeed, in a conventional system, such a pressure wave can destroy the enclosure and turn the panels of the enclosure itself into further projectiles that are likely to contribute to the damage caused.

(21) In an enclosure of the type represented by the present disclosure, these catastrophic effects are somewhat mitigated. In the first instance, the thin membranes 16 would be ruptured by the overpressures created by the explosion. Consequently, rather than containing and reflecting the overpressure, the high pressure wave will be transmitted outside the enclosure and will rapidly be dissipated. Energy will be dispersed and hence, the panels 14 of the enclosure system 2 will not be dislodged simply by virtue of the overpressures experienced within the enclosure. In the alternative embodiment illustrated in FIGS. 5 and 6, the membrane sheets 26 will not be ruptured but, rather, will be forced away from the mesh panel 18c to release the gasses and thus dissipate the high pressures.

(22) The mesh sheets of the panels 18 absorb and disperse the impact energy of projectiles formed from the fragments of the apparatus generated during the explosive incident. As an example, each mesh sheet serves to prevent projectiles having kinetic energy of between 150 joules and 450 joules from escaping from the enclosure system. Additional energy from projectiles is absorbed by each successive mesh sheet of a panel 18 until all the energy is removed and the projectiles are eventually stopped or at least slowed significantly to minimize the damage caused thereby. It is preferred that two mesh sheets are provided in each panel as discussed above.

(23) As a result, providing an enclosure according to the present disclosure around a vacuum and/or abatement system, serves to protect personnel working in the vicinity from injury caused by projectiles generated as a result of an energetic reaction of process by-product of the pump, valve or abatement equipment.

(24) Whilst the embodiments described herein comprise panels according to the disclosure exclusively, it is envisaged that these panels can be provided in combination with more conventional metal plates for some sections of the enclosure but the effectiveness of the mitigating measures will, correspondingly be reduced and the plates may represent hazardous projectiles. Alternatively, the support structure 20 of some or each of the panels 14 may be formed integrally with the structural frame 12 of the enclosure 2. In this instance the enclosure will take longer to install and access into the enclosure would be less readily achieved. A combined approach is envisaged in this integral approach, whereby one or more sections of the enclosure comprise panels 14 of the type comprising an external structural framework 20 that can be removably mounted on and connected to the main enclosure frame 12.