Abatement apparatus for treating an effluent gas stream and method thereof

Abstract

The present invention provides an abatement apparatus for treating an effluent gas stream from a manufacturing processing tool. The abatement apparatus comprises a treatment chamber at least partially defined by a first porous wall, and comprising an inlet configured to enable an effluent gas stream from the manufacturing processing tool to enter the treatment chamber; a second porous wall generally surrounding the first porous wall and defining therebetween a second chamber, the second chamber being porous to allow gas flow therethrough; one or more heating elements are arranged within the second chamber and are configured to heat the gas flowing therethrough during use; a third porous wall generally surrounding the second chamber and defining therebetween a third chamber, the third chamber containing a relatively thermally insulating material, said third chamber being porous to allow gas flow; and a gas inlet. Wherein, the apparatus is configured such that, in use, a gas flow is conveyed from the gas inlet through the third chamber and the second chamber to the treatment chamber where it reacts with the effluent gas stream.

Description

[0001] ABATEMENT APPARATUS FOR TREATING AN EFFLUENT GAS STREAM AND METHOD THEREOF

[0002] Field

[0003] The present invention relates to an abatement apparatus for treating an effluent gas stream from a manufacturing processing tool. The present invention also relates to a method of abatement of an effluent gas stream from a manufacturing processing tool.

[0004] Background

[0005] Abatement apparatus are known and are typically used for treating an effluent gas stream from a manufacturing processing tool used in, for example, the semiconductor or flat panel display manufacturing industry. During use of the manufacturing processing tool, residual perfluorinated compounds (PFCs) and other compounds may be present in the effluent gas stream pumped from the process tool. PFCs are difficult to remove from the effluent gas and their release into the environment is undesirable because they are known to have relatively high greenhouse activity. Typically, abatement apparatus use combustion to remove the PFCs and other compounds from the effluent gas stream.

[0006] There is a desire to improve the efficiency of the abatement process, particularly there is a desire to reduce energy use during abatement. Thermal losses within the system are undesirable as the heating of the abatement apparatus housing can be dangerous, as well as making the apparatus more expensive to operate.

[0007] The present invention aims to solve, at least in part, these and other problems associated with the prior art.

[0008] Summary

[0009] In an aspect, the present invention provides an abatement apparatus for treating an effluent gas stream from a manufacturing processing tool. The abatement apparatus comprises a treatment chamber at least partially defined by a first porous wall. The treatment chamber comprises an inlet configured to enable an effluent gas stream from the manufacturing processing tool to enter the treatment chamber.

[0010] The abatement apparatus further comprises a second porous wall generally surrounding the first porous wall and defining therebetween a second chamber. The second chamber is porous to allow gas flow therethrough. One or more heating elements are arranged within the second chamber. The one or more heating elements are configured to heat gas flowing through the second chamber when the abatement apparatus is in use. As will be explained in further detail elsewhere herein, the heating of the gas by the heating elements may comprise both direct and indirect heating. The abatement apparatus further comprises a third porous wall generally surrounding the second porous wall and defining therebetween a third chamber. The third chamber contains a relatively thermally insulating material. The third chamber is porous to allow gas flow therethrough. The abatement apparatus further comprises a gas inlet.

[0011] The apparatus is configured such that, in use, a gas flow is conveyed from the gas inlet through the third chamber and the second chamber to the treatment chamber where it reacts with the effluent gas stream.

[0012] The manufacturing processing tool may be a tool used in, for example, the semiconductor or flat panel display manufacturing industry. The skilled person will appreciate that the abatement apparatus according to the present invention is not limited to abatement of gases from a particular manufacturing processing tool used in a specific industry. Rather, the abatement apparatus may be selected according to the composition and / or characteristics (e.g. temperature, flow rate) of the effluent gas stream.

[0013] The composition and characteristics of the effluent gas stream may depend on the manufacturing processing tool to which the abatement apparatus is connected when in use. Furthermore, the composition and / or the characteristics of said effluent gas stream may depend on the specific processing step occurring in the manufacturing processing tool. Typically, the effluent gas stream may comprise constituent components that are toxic and / or damaging to the atmosphere because of their high greenhouse activity. For example, residual perfluorinated compounds (PFC’s) and other compounds may be present in the effluent gas stream and should be removed in the abatement apparatus.

[0014] The treatment chamber may define the region of the abatement apparatus where the effluent gas stream may react with the gas flow to treat the effluent gas stream. The treatment chamber has an inlet that may be fluidly coupled to the processing tool. In use, the effluent gas stream may flow through the inlet into the treatment chamber. In some embodiments, the treatment chamber may comprise a plurality of inlets, wherein each inlet is fluidly coupled to the processing tool. The plurality of inlets may divide the flow of the effluent gas stream as it enters the treatment chamber and provide improved dispersion therein. Alternatively, in some embodiments, each inlet may be fluidly coupled to a different processing tool, and configured to enable an effluent gas stream from said processing tool to enter the treatment chamber. The treatment chamber may further comprise an outlet through which gases may exit the treatment chamber following treatment of the effluent gas stream.

[0015] The treatment chamber is at least partially defined by the first porous wall. The treatment chamber may be generally cylindrical, although the skilled person will appreciate that it is not limited to this shape. The inlet may be at a first end, and the outlet may be at a second end. The first porous wall may be a perforated wall, or a substantially regular openwork mesh. Preferably, the first porous wall may be a generally tubular wall. The first porous wall may enable gas to pass through during use of the abatement apparatus. The first porous wall may comprise a metallic material, for example, those sold under the trade names Inconel™ or Kanthal™. The material of the first porous wall may be selected such that it can survive contact with the effluent stream without significant degradation. Preferably, the first porous wall may comprise a metallic sheet with a plurality of perforations therethrough.

[0016] The second porous wall may be a perforated wall, or a substantially regular openwork mesh. Preferably, the second porous wall may be a generally tubular wall. The second porous wall may generally surround the first porous wall. The second porous wall may enable gas to pass through during use of the abatement apparatus. The second porous wall may comprise a metallic material, for example, a stainless steel alloy. This material may be selected such that it does not melt or degrade at the operating temperature of the abatement apparatus. Preferably, the second porous wall may comprise a metallic sheet with a plurality of perforations therethrough. In some embodiments, the first and second porous walls may comprise the same material.

[0017] Typically, the perforations through the first porous wall and / or the second porous wall may be generally circular. Preferably, the perforations may have a diameter of from about 0.5 mm to 2 mm, preferably about 1 mm. The size and density of the perforations may be selected according to the desired flow rate of gas when in use.

[0018] The second chamber is defined between the first generally tubular wall and the second generally tubular wall. Preferably, the second chamber may be generally tubular. In other words, the second chamber may be an annular cylinder. Preferably, the second chamber may be coaxial with first chamber. The second chamber may generally surround the treatment chamber.

[0019] The second chamber being porous may mean that the walls defining the second chamber are configured to allow gas to flow therethrough and to pass through the second chamber. In other words, during use, gas may flow through the second generally tubular wall into the second chamber, then through the first generally tubular wall into the treatment chamber.

[0020] The one or more heating elements may comprise, for example, resistive heating elements and / or infra-red (IR) heating elements. Preferably, the one or more heating elements may consist of resistive heating elements. Preferably, the one or more heating element(s) may not be in contact with the first porous wall or the second porous wall. Preferably, the heating element(s) may be arranged between the first porous wall and the second porous wall. Preferably, in use, the effluent gas stream does not come into contact with the heating element(s). Advantageously, such a configuration may reduce the likelihood of contamination and / or corrosion of the heating element(s).

[0021] Without wishing to be bound by theory, during operation, there may be both direct and indirect heat transfer between the heating element(s) and the gas flow. The direct heat transfer may comprise the one or more heating element(s) transferring heat to the gas flowing through the second chamber. The indirect heat transfer may comprise the heating element(s) transferring heat to the first porous wall and / or the second porous wall. Then, the first porous wall and / or the second porous wall may transfer heat to the gas flowing through the second chamber. In some embodiments, the one or more heating elements may be configured to transfer infrared radiation to the first and / or second porous walls. The first and / or second porous walls may then transfer heat to the gas flowing through.

[0022] In some embodiments, the second chamber may contain only the one or more heating elements. It will be appreciated that, during use, the gas flow may also pass through the second chamber.

[0023] Typically, the abatement apparatus may comprise a plurality of heating elements that are arranged within the second chamber. Typically, the one or more heating elements may be substantially evenly spaced about the second chamber. Advantageously, this may enable more uniform heating of the gas flow through the second chamber during use.

[0024] Typically, the abatement apparatus may be configured such that the effluent gas does not enter the second chamber during use. Advantageously, this may reduce the likelihood of degradation of the one or more heating elements.

[0025] The third porous wall may be a wall comprising perforations, or a substantially regular openwork mesh. Preferably, the third porous wall may be a generally tubular wall. The third porous wall may generally surround the second porous wall. The third porous wall may enable gas to pass through during use of the abatement apparatus. The third porous wall may comprise a metallic material, for example, a stainless steel alloy. Preferably, the third porous wall may comprise a metallic sheet with a plurality of perforations therethrough. The size and density of the perforations may be selected according to the desired flow rate of gas when in use.

[0026] The third chamber is defined between the second generally tubular wall and the third generally tubular wall. Preferably, the third chamber may be generally tubular. In other words, the third chamber may be an annular cylinder. Preferably, the third chamber may be coaxial with first chamber and the second chamber. Typically, the relatively thermally insulating material within the third chamber may be configured to allow the gas to flow through or across it during use of the abatement apparatus. The relatively thermally insulating material may be configured to allow gas flow through and / or across it, whilst reducing heat transfer through the third chamber. The relatively thermally insulating material may be selected such that it is unreactive with the gas flow, even at operational temperatures.

[0027] The third chamber may be substantially filled with the relatively insulating material. Preferably, at least 50% of the volume of the third chamber may be filled with the relatively insulating material, more preferably at least 75% of the volume of the third chamber, for example, at least 85% of the volume of the third chamber.

[0028] By way of non-limiting example, the relatively thermally insulating material may be an open- celled porous solid, or a plurality of porous or non-porous particles. For the avoidance of doubt, the thermally insulating material may be distinct and separate from the second porous wall, and / or third porous wall. The relatively thermally insulating material may be a solid material. The relatively thermally insulating material may comprise a monolithic structure, or a plurality of particulates.

[0029] The third chamber being porous may mean that it is configured to allow gas to flow therethrough and / or around and / or through the relatively thermally insulating material located therein. Preferably, the third chamber is optically opaque, whilst allowing a gas flow rate sufficient for treatment of the effluent gas flow in the treatment chamber. In other words, the third chamber may be arranged such that there is no linear path from the third porous wall to the second porous wall that is not blocked (i.e. intersected) by the relatively thermally insulating material.

[0030] In abatement apparatus of the prior art, the outer wall of the treatment chamber housing has been found to reach temperatures of about 200 °C. This is both inefficient and potentially dangerous. The running costs of such abatement apparatus are also increased by such thermal losses. Upon investigation, the present inventors have established that the heat is transferred to the outer wall of the treatment chamber housing from heating elements configured to heat the gas as it flows into the treatment chamber. Advantageously, the present inventors have established that by providing the third chamber containing relatively thermally insulating material, heat transfer outwards in the direction of a treatment chamber housing may be significantly reduced. The present invention may not require additional insulation sleeves and / or cooling devices arranged about the treatment chamber housing.

[0031] The gas inlet, in use, may be coupled to a gas source. The gas source may be configured to supply a thermally conductive gas to react with the effluent gas stream in the treatment chamber. The gas inlet may be arranged such that the flow path of gas from the gas inlet to the treatment chamber passes through the third porous wall into the second chamber, then through and / or across the relatively thermally insulating material, then through the second porous wall into the first chamber, then through and / or across the relatively thermally conductive material to increase the temperature of the gas, then through the first porous wall and into the treatment chamber, where it reacts with the effluent gas stream.

[0032] In the present invention, the abatement apparatus may be configured such that the effluent gas does not enter the second chamber or the third chamber. This may be achieved by ensuring a positive gas flow into the treatment chamber to react with the effluent gas flow. Additionally, or alternatively, the outlet of the treatment chamber may be connected to a partially evacuated duct to maintain the treatment chamber at a lower pressure than the second chamber or third chamber.

[0033] Advantageously, the present invention provides a more efficient abatement apparatus. The present invention also provides an abatement apparatus having reduced thermal losses through the outer wall defining the treatment chamber housing.

[0034] Typically, the abatement apparatus further comprises an outer wall generally surrounding the third porous wall, and defining therebetween a plenum. The outer wall may be the wall defining the treatment chamber housing. The plenum generally surrounds the third porous wall. The gas inlet may be arranged such that gas flow therethrough is conveyed into the plenum prior to entering the third chamber. Accordingly, the plenum may disperse the gas flow such that it enters the third chamber at multiple locations. Advantageously, this may improve the dispersion of the gas flow through the third and second chambers, increasing efficiency.

[0035] Typically, the relatively thermally insulating material may have a thermal conductivity less than about 10 Wm’1K’1, preferably less than about 1 Wnr1K’1, more preferably less than about 0.1 Wm’1K’1. The third chamber containing the relatively thermally insulating material may have a lower thermal conductivity than a comparative example in which the third chamber contains no solid material (i.e. in which the third chamber is empty). Without wishing to be bound by theory, when the third chamber is empty, heat can radiate to the relatively conductive walls of the third chamber and thereby be conducted to the third porous wall. The presence of the relatively thermally insulating material may reduce the heat transfer to the walls defining the third chamber, and thereby may reduce the temperature of the third porous wall.

[0036] The relatively thermally insulating material may be relatively insulating in comparison to the material of the one or more walls. The relatively thermally insulating material may be a solid. The relatively thermally insulating material may be configured to reduce the transfer of heat through the third chamber to the third porous wall. The relatively thermally insulating material may be configured to allow the gas flow to pass through and / or around it within the third chamber.

[0037] The relatively thermally insulating material within the third chamber may be configured to reduce the infra-red radiation transferring from the second porous wall to the third porous wall during use. As mentioned previously, during use, the first and second porous walls may be heated by the heating element(s), said walls being configured to transfer heat to the gas flowing through. Some heat may radiate from the second porous wall outward into the third chamber. However, the relatively thermally insulating material may be configured to reduce the heat radiated through the third chamber to the third porous wall.

[0038] Typically, the relatively thermally insulating material contained in the third chamber may be a relatively thermally insulating particulate matter. Preferably, the relatively thermally insulating material contained in the third chamber may be a packed bed of relatively thermally insulating particulate matter. Advantageously, the relatively thermally insulating particulate matter may allow gas flow, whilst reducing heat transfer through the third chamber. Thereby, heat transfer to the treatment chamber housing may be reduced. As the gas flow enters the third chamber, there may be a pressure drop due to the particulate matter. This may advantageously aid dispersion of the gas.

[0039] The abatement apparatus may be supplied with the relatively thermally insulating particulate matter packed within the third chamber. In some embodiments, the third chamber may be openable to enable replacement of the relatively thermally insulating particulate matter.

[0040] Typically, the relatively thermally insulating particulate matter comprises pumice and / or micafil vermiculite. Typically, the relatively thermally insulating particulate matter is the same (i.e. material and / or particle geometry) throughout the third chamber.

[0041] Typically, the one or more heating elements may be resistive heating elements and / or infrared heating elements. Preferably, there may be from about 1 to about 24 heating elements.

[0042] Typically, during use, the one or more heating elements are configured to heat to a temperature from about 500 °C to about 1200 °C. Preferably, the one or more heating elements are configured to heat to a temperature from about 700 °C to about 1000 °C. More preferably, the one or more heating elements are configured to heat to a temperature from about 900 °C to about 1000 °C. Most preferably, the one or more heating elements are configured to heat to a temperature from about 950 °C to about 980 °C. Advantageously, this may ensure that the gas flow into the treatment chamber is heated to a temperature to enable efficient reaction with the effluent gas. Typically, the gas flow conveyed through the gas inlet comprises dry air (e.g. compressed dry air) and / or nitrogen. Preferably, the gas flow is substantially free from fossil fuels (e.g. methane). Advantageously, this may be more environmentally friendly than prior art abatement solutions, as fossil fuels are not required in the reaction with the effluent gas flow.

[0043] In a further aspect, the present invention provides a method of abatement of an effluent gas stream from a manufacturing process tool. The method comprises the steps of: a) providing an abatement apparatus according to any embodiment of the preceding aspect; b) operating the one or more heating elements; c) conveying a gas flow from the gas inlet to the treatment chamber through the third chamber and the second chamber; d) abating the effluent gas stream with the gas flow in the treatment chamber; and e) conveying the abated gas stream through an outlet of the treatment chamber.

[0044] Advantageously, the method of present invention provides a more efficient method of operation of an abatement apparatus. Specifically, the gas flow is heated efficiently as it flows through the second chamber. Furthermore, the method of the present invention also provides an abatement apparatus having reduced thermal losses through the treatment chamber housing, due to the insulating effect of the relatively thermally insulating material contained within the third chamber.

[0045] Further features and advantages may be as described in any embodiment of the preceding aspect.

[0046] Typically, in step (b) the heating elements may heat to a temperature from about 500 °C to about 1200 °C, preferably from about 700 °C to about 1000 °C, more preferably from about 900 °C to about 1000 °C, most preferably from about 950 °C to about 980 °C. Advantageously, this may allow the gas flow passing through the second chamber to be heated prior to entering the treatment chamber. The heating of the gas flow passing through the second chamber may be, in part, from heat that is transferred from the heating element(s) to the first and / or second porous walls, which is then transferred from said first and / or second porous walls to the gas flow. This may enable effective abatement of the effluent gas stream in the treatment chamber.

[0047] Typically, the gas flow may comprise compressed dry air and / or nitrogen. Advantageously, the method of the present invention may enable abatement of the effluent gas stream without requiring fossil fuel (e.g. methane) to provide the heat to abate the process gases. For the avoidance of doubt, all aspects and embodiments described herein may be combined mutatis mutandis. It is also to be understood that this invention is not limited to the embodiments and aspects set forth in the following detailed description or illustrated in the drawings. The invention may be implemented in various other embodiments and is capable of being implemented in alternative ways not expressly disclosed herein.

[0048] Brief Description of Figures

[0049] Preferred features of the present invention will now be described, by way of example, with reference to the accompanying figures, in which:

[0050] Figure 1 illustrates a cross-sectional schematic of an abatement apparatus according to the present invention;

[0051] Figure 2 illustrates a flow diagram of a method of abating an effluent gas flow from a processing tool according to the present invention.

[0052] Detailed Description

[0053] Figure 1 shows a cross-sectional schematic of an abatement apparatus (1) according to the present invention.

[0054] The abatement apparatus (1) comprises a treatment chamber (2). The treatment chamber (2) defines the region of the abatement apparatus where, when in use, the effluent gas stream (Gi) reacts with the gas flow (G2) to treat the effluent gas stream (G1). The treatment chamber (2) comprises an inlet (3) at a first end. In other embodiments, the treatment chamber (2) may comprise a plurality of inlets. The inlet (3) is configured to enable the effluent gas stream (G1) from the manufacturing processing tool (not shown) to enter the treatment chamber (2). Specifically, the inlet (3) is configured to be fluidly coupled to one or more vacuum pumps (not shown), wherein the vacuum pump(s) evacuate effluent gas stream (G1) from the processing tool and convey it into the abatement apparatus (1).

[0055] The treatment chamber (2) comprises an outlet (4) at a second end, opposite the first end. The outlet (4) may be configured to allow the treated (e.g. combusted) effluent gas stream (G1) to exit the treatment chamber (2). The treatment chamber (2) is generally cylindrical. The treatment chamber (2) is partially defined by a first porous wall (5). The first porous wall (5) is generally tubular. The first porous wall (5) may be a metallic sheet with a plurality of perforations.

[0056] The abatement apparatus further comprises a second porous wall (7). The second porous wall (7) is generally tubular. The second porous wall (7) may be a metallic sheet with a plurality of perforations. The second porous wall (7) generally surrounds the first porous wall (5). The first porous wall (5) and second porous wall (7) define therebetween a second chamber (8). The second chamber (8) is porous and allows gas flow therethrough.

[0057] The second chamber (8) contains heating elements (6). The heating elements (6) are located between the first porous wall (5) and the second porous wall (7). The heating elements (6) may be arranged throughout the second chamber (8). In other words, the heating elements (6) may be arranged about the circumference of the second chamber (8). The heating elements may be substantially evenly spaced within the second chamber (8). The heating elements (6) may be arranged to provide substantially uniform heating of the gas flowing through the second chamber (8). Preferably, the heating elements (6) are resistive heating elements. The heating elements (6) may be spaced to enable gas to flow through the second chamber (8) during use.

[0058] In use, the heating elements (6) heat the gas flowing through the second chamber (8). The heating of the gas flow passing through the second chamber (8) may be, in part, from heat that is transferred from the heating element(s) (6) to the first (5) and / or second (7) porous walls, which is then transferred from said first (6) and / or second (7) porous walls to the gas flow. Preferably, the heating elements (6) heat to a temperature of from about 950 °C to about 980 °C.

[0059] A third porous wall (9) generally surrounds the second porous wall (7). The third porous wall

[0060] (9) and second porous wall (7) define therebetween a third chamber (10). The third chamber

[0061] (10) contains a relatively thermally insulating material (11).

[0062] In this embodiment, the relatively thermally insulating material (11) comprises relatively thermally insulating particles. The third chamber (10) contains a packed bed of relatively thermally insulating particles (11). The gaps between said particles enable gas to flow through the third chamber (10). The particles may be porous or substantially non-porous. The relatively thermally insulating particles (11) may reduce heat transfer through the third chamber (10).

[0063] The abatement apparatus (1) further comprises an outer wall (12) generally surrounding the third porous wall (9). The outer wall (12) is preferably a wall defining the treatment chamber housing. The outer wall (12) and third porous wall (9) define therebetween a plenum (13).

[0064] The abatement apparatus (1) further comprises a gas inlet (14). The gas inlet (14) is arranged such that, during use, gas flow may be conveyed through the gas inlet (14) into the plenum (13), and from the plenum (13) into the third chamber (10). This may increase dispersion of the gas flow through the third chamber (10) and second chamber (8).

[0065] The apparatus (1) is configured such that, in use, a gas flow (G2) is conveyed from the gas inlet (14) through the third chamber (10) and the second chamber (8) to the treatment chamber (2) where it reacts with the effluent gas stream (Gi). The treated gas stream may exit the apparatus through the outlet (4) of the treatment chamber (2).

[0066] Figure 2 shows a flow diagram of a method of abating an effluent gas flow from a processing tool according to the present invention.

[0067] The method comprises the steps of providing an abatement apparatus according to any embodiment described herein (15). For example, the abatement apparatus may be that described in relation to Figure 1. Next, the one or more heating elements are operated (16). Preferably, during this step, the effluent gas stream is not being conveyed through the abatement apparatus.

[0068] Once the one or more heating elements have been heated to the desired temperature, gas flow is conveyed from the gas inlet into the treatment chamber through the third chamber and the second chamber (17). Preferably, the gas flow comprises dry air (e.g. compressed dry air) and / or nitrogen. Typically, the one or more heating elements is / are heated to a temperature greater than about 500 °C, preferably greater than about 950 °C. Both via direct transfer of heat from the heating elements to the gas flow, and via indirect transfer of heat from the heating elements to the first porous wall and second porous wall then from said porous walls to the gas flow, this will heat the gas prior to it entering the treatment chamber.

[0069] Next, as the effluent gas stream is conveyed through the treatment chamber, it is abated by reaction with the gas flow (18). Finally, the abated gas stream is conveyed through the outlet of the treatment chamber (19).

[0070] For the avoidance of doubt, features of any aspects or embodiments recited herein may be combined mutatis mutandis. It will be appreciated that various modifications may be made to the embodiments shown without departing from the spirit and scope of the invention as defined by the accompanying claims as interpreted under patent law, including the doctrine of equivalents. Any reference to claim elements in the singular, for example, using the articles “a”, “an”, “the” or “said”, is not to be construed as limiting the element to the singular.

[0071] Reference Key

[0072] 1. Abatement apparatus

[0073] 2. Treatment chamber

[0074] 3. Inlet

[0075] 4. Outlet

[0076] 5. First porous wall

[0077] 6. Heating element

[0078] 7. Second porous wall

[0079] 8. Second chamber

[0080] 9. Third porous wall

[0081] 10. Third chamber

[0082] 11. Relatively thermally insulating material

[0083] 12. Outer wall

[0084] 13. Plenum

[0085] 14. Gas inlet

[0086] 15. Method step

[0087] 16. Method step

[0088] 17. Method step

[0089] 18. Method step

[0090] 19. Method step

Claims

Claims1 . An abatement apparatus for treating an effluent gas stream from a manufacturing processing tool, comprising: a treatment chamber at least partially defined by a first porous wall, and comprising an inlet configured to enable an effluent gas stream from the processing tool to enter the treatment chamber; a second porous wall generally surrounding the first porous wall and defining therebetween a second chamber, the second chamber being porous to allow gas flow therethrough; wherein one or more heating elements are arranged within the second chamber and are configured to heat gas flowing therethrough during use; a third porous wall generally surrounding the second chamber and defining therebetween a third chamber, the third chamber containing a relatively thermally insulating material, said third chamber being porous to allow gas flow therethrough; and a gas inlet; wherein the apparatus is configured such that, in use, a gas flow is conveyed from the gas inlet through the third chamber and the second chamber to the treatment chamber where it reacts with the effluent gas stream.

2. The abatement apparatus according to claim 1 , further comprising an outer wall generally surrounding the third porous wall, and defining therebetween a plenum.

3. The abatement apparatus according to claim 1 or 2, wherein a plurality of heating elements are arranged within the second chamber.

4. The abatement apparatus according to any preceding claim, configured such that the effluent gas does not enter the second chamber.

5. The abatement apparatus according to any preceding claim, wherein the one or more heating elements are substantially evenly spaced about the second chamber.

6. The abatement apparatus according to any preceding claim, wherein the relatively thermally insulating material has a thermal conductivity less than about 10 Wnr1K’1, preferably less than about 1 Wnr1K’1, more preferably less than about 0.1 Wnr1K’1.

7. The abatement apparatus according to any preceding claim, wherein the relatively thermally insulating material contained in the third chamber is a relatively thermally insulating particulate matter.

8. The abatement apparatus according to claim 7, wherein the relatively thermally insulating material contained in the third chamber is a packed bed of relatively thermally insulating particulate matter.

9. The abatement apparatus according to claim 8, wherein the relatively thermally insulating particulate matter comprises pumice and / or micafil vermiculite.

10. The abatement apparatus according to any preceding claim, wherein the one or more heating elements are resistive heating elements and / or infra-red heating elements.11 . The abatement apparatus according to any preceding claim, wherein the one or more heating elements are configured to heat to a temperature from about 500 °C to about 1200 °C, preferably from about 700 °C to about 1000 °C, more preferably from about 900 °C to about 1000 °C, most preferably from about 950 °C to about 980 °C.

12. The abatement apparatus according to any preceding claim, wherein the gas flow conveyed through the gas inlet comprises compressed dry air and / or nitrogen.

13. A method of abatement of an effluent gas stream from a manufacturing processing tool, comprising the steps of: a) providing an abatement apparatus according to any preceding claim; b) operating the one or more heating elements; c) conveying a gas flow from the gas inlet to the treatment chamber through the third chamber and the second chamber; d) abating the effluent gas stream with the gas flow in the treatment chamber; ande) conveying the abated gas stream through an outlet of the treatment chamber.

14. The method according to claim 13, wherein in step (b) the heating elements are heated to a temperature from about 500 °C to about 1200 °C, preferably from about 700 °C to about 1000 °C, more preferably from about 900 °C to about 1000 °C, most preferably from about 950 °C to about 980 °C.

15. The method according to claim 13 or 14, wherein the gas flow comprises compressed dry air and / or nitrogen.

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