FIELD

The invention relates to an exhaust abatement apparatus and a method for abating reactive gasses.

BACKGROUND

An exhaust abatement apparatus, also called exhaust combustion apparatus, may be used to abate reactive gasses present in the exhaust gasses from a process chamber of semiconductor processing apparatus, e.g. a chemical vapor deposition (CVD) apparatus, an atomic layer deposition (ALD) apparatus, before releasing these oftentimes hazardous exhaust gasses to the environment. The exhaust gasses are injected into an abatement chamber in which the reactive gasses react with an oxidation gas which is present in said abatement chamber. Generally, oxygen is used as the oxidation gas. A nozzle is used to inject and disperse the exhaust gasses into the abatement chamber.

SUMMARY

In prior art exhaust abatement apparatus, clogging of the nozzle may occur due to the deposition of solids on the nozzle formed by the reaction of the exhaust gasses with the oxidizing gas.

The present invention has as an object to provide an exhaust abatement apparatus which is less complex, prevents or at least reduces clogging of the exhaust gas nozzle and prevents or at least reduces unwanted deposition on a wall of the abatement chamber near the nozzle.

To that end, the invention provides an exhaust abatement apparatus according to claim 1. More particularly, the invention provides an exhaust abatement apparatus comprising an abatement chamber housing having abatement chamber housing walls bounding an abatement chamber, an abatement chamber exhaust for exhausting gas from the abatement chamber, and a nozzle extending through one of the housing walls.

The nozzle includes a nozzle housing defining an outer channel extending along a central axis, and a central pipe at least partially extending in and being concentric with the outer channel and bounding an inner channel extending along the central axis. The central pipe has an inner channel inlet which is outside of the abatement chamber and an inner channel outlet which is inside the abatement chamber, the inner channel outlet being bounded by a distal end of the central pipe.

The outer channel is ring-shaped in cross section and has an outer channel inlet and an outer channel outlet which is inside the abatement chamber. The outer channel outlet is ring-shaped and is bounded by the distal end of the central pipe and a distal end of the nozzle housing.

The nozzle further comprises a drag flow interrupter at the distal end of the nozzle housing and having a transverse dimension which is substantially larger than an outer transverse dimension of the ring-shaped outer channel outlet, so as to be configured to interrupt a drag of flow of oxidation gas along the outer channel outlet.

In an embodiment, the nozzle housing may comprise an outer pipe in which the central pipe is concentrically mounted. The outer channel is formed between the outer pipe and the central pipe. Such a configuration is simple and robust. The drag flow interrupter may be embodied as a plate or disk extending perpendicular to the central axis and mounted at the distal end of the outer pipe at the outer channel outlet. The outer diameter of the disk or plate is substantially larger than the outer diameter of the outer pipe, e.g. 20% larger.

The invention also provides a method according to claim 13. In particular the invention provides a method for abating reactive gasses. The method comprises: providing an exhaust abatement apparatus according to the invention; providing an oxidation gas in the abatement chamber, supplying a reactive gas to the abatement chamber via the inner channel outlet; supplying a protective gas to the abatement chamber via the outer channel outlet simultaneously with supplying the reactive gas to the abatement chamber; and interrupting a drag of flow of oxidation gas along the outer channel outlet by means of the drag flow interrupter.

With the exhaust abatement apparatus and the method according to the invention, the inner channel outlet can be used to supply the reactive gas to the abatement chamber whilst at the same time the outer channel outlet can be used to supply a protective gas. The reactive gas may be part of an exhaust gas coming from a process chamber from e.g. semiconductor processing apparatus. The inner channel inlet may e.g. be fluidly connected to a process chamber exhaust of the process chamber, such that the exhaust gas can flow to and through the inner channel. The reactive gas may e.g. be trimethylaluminum (TMA) which was not completely used in an atomic layer deposition (ALD) apparatus. The protective gas may be an inert gas, i.e. inert to the reactive gas. It may, for example, be nitrogen (N2).

The cross section of the outer channel, as well as the outer channel outlet, is ring-shaped. Ring-shaped in this respect does not mean that the outer and inner circumferences of the ring-shaped outer channel need to be circular. In fact, the outer and inner circumferences of the ring-shaped outer channel may have any closed circumferential shape, e.g. circular, elliptic, rectangular, square, polygonic, etc.

Because of this shape of the outer channel, and the fact that the central pipe is inside the outer channel, the protective gas coming out of the outer channel outlet, completely surrounds the reactive gas coming out of the inner channel outlet. The reactive gas is thus shielded from the oxidation gas by the protective gas when entering the abatement chamber. This in turn means that the reactive gas does not oxidize or burn directly at the inner channel outlet of the nozzle.

After having left the nozzle and being moved into the abatement chamber over some distance, the reactive gas, the protective gas, and the oxidation gas start to mix so that the reactive gas only then can be oxidized by the oxidation gas. Thus, by supplying a protective gas via the outer channel outlet, the location where the oxidation of the reactive gas occurs is at a distance from the nozzle. This distance which is created by the flow of protective gas prevents clogging of the nozzle outlet. Also, because the oxidation is away from the nozzle, products of the oxidation process, e.g. solid particles of AI2O3 are not deposited on the wall though which the nozzle extends nor on the nozzle itself. Another advantage is that before the reactive gas mixes with oxidation gas, the reactive gas is diluted by the protective gas. Thus, the reaction of the diluted reactive gas with the oxidation gas will be more controlled resulting in a smaller particle size.

The drag flow interrupter ensures that any drag of oxidation gas along the nozzle by virtue of the outflowing reactive gas and protective gas is interrupted so that the distance from the inner channel outlet to the location where the reactive gas starts to mix with and thus react with the oxidation gas is increased. With the drag flow interrupter the distance between the inner channel outlet and the location where the first mixing occurs can be tailored such that this distance is large enough to prevent clogging of the nozzle by reaction products.

The present invention will be further elucidated with reference to figures of an example in which various embodiments of the invention are incorporated. The embodiments may be combined or may be applied separately from each other.

BRIEF DESCRIPTION OF THE FIGURES Fig. 1 shows an example of the exhaust abatement apparatus according to the description;

Fig. 2 shows an example of the nozzle according to the description;

Fig. 3 shows an example of the nozzle according to the description with a curved drag flow interrupter;

Fig. 4 shows an example of the nozzle according to the description with the outer channel inlet inside the abatement chamber.

DETAILED DESCRIPTION OF THE FIGURES

In this application similar or corresponding features are denoted by similar or corresponding reference signs. The description of the various embodiments is not limited to the examples shown in the figures and the reference numbers used in the detailed description and the claims are not intended to limit the description of the embodiments, but are included to elucidate the embodiments by referring to the example shown in the figures.

In the most general terms, the invention relates to an exhaust abatement apparatus 10 comprising an abatement chamber housing 12 having abatement chamber housing walls 14 bounding an abatement chamber 16. The abatement apparatus 10 comprises an abatement chamber exhaust 18 for exhausting gas from the abatement chamber 16, and a nozzle 20 extending through one of the housing walls 14.

As is visible in the examples shown in figures 2-4, the nozzle 20 includes a nozzle housing 22 defining an outer channel 24 extending along a central axis 26, and a central pipe 28 at least partially extending in and being concentric with the outer channel 24 and bounding an inner channel 30 extending along the central axis 26. The central pipe 28 has an inner channel inlet 32 which is outside of the abatement chamber 16 and an inner channel outlet 34 which is inside the abatement chamber 16. The inner channel outlet 34 is bounded by a distal end 28a of the central pipe 28. The outer channel 24 is ring-shaped in cross section and has an outer channel inlet 36 and an outer channel outlet 38 which is inside the abatement chamber 16. The outer channel outlet 40 is ring-shaped and is bounded by the distal end 28a of the central pipe 28 and a distal end 22a of the nozzle housing 22.

The nozzle 20 further comprises a drag flow interrupter 40 at the distal end 22a of the nozzle housing 22 and having a transverse dimension which is substantially larger than an outer transverse dimension of the ring-shaped outer channel outlet 38, so as to be configured to interrupt a drag of flow of oxidation gas along the outer channel outlet 38.

The effects and advantages of the exhaust abatement apparatus 10 have been described in the summary section and these effects and advantages are inserted here by reference.

In an embodiment, as shown in figures 2 and 3, the nozzle housing 22 comprises an outer pipe 42 extending along the central axis 26 through the wall 14 of the housing walls 14.

The outer pipe 42 and central pipe 28 may thus form two concentric pipes 28, 42, wherein the inner channel 30 is formed inside the central pipe 28, and the outer channel 24 is formed between the outer and central pipes 42, 28. Such a configuration is simple and robust. The nozzle 20 can protrude through the abatement chamber housing wall 14 as a single entity and therefore only one hole in the wall 14 is required (see Figs. 2 and 3) as opposed to embodiments in which the outer channel is formed entirely inside the abatement chamber 16 (see Fig. 4).

In an embodiment, as shown in figures 2 and 4, the drag flow interrupter 40 is embodied as a plate or disk extending perpendicular to the central axis 26.

The disk or a plate may have a flat surface, which, in this embodiment, is perpendicular to the central axis 26. Without the drag flow interrupter 40, gas inside the abatement chamber 16 which is radially adjacent to the nozzle housing 22, may be dragged along the nozzle housing 22 to the distal end 22a of said nozzle housing 22 by virtue of a flow of protective gas leaving the outer channel outlet 38. The flat surface of the drag flow interrupter 40 interrups this drag flow of oxidation gas and thus prevents that oxidation gas is mixed with reactive gas directly at the inner channel outlet 34 and the outer channel outlet 38. A circumference of the plate or disk does not have to be a circle, but may have any shape, as long as it sufficiently interrupts a drag flow along the nozzle housing 22 so as to prevent mixing of reactive gas and oxidation gas directly at the outlets 34, 38 of the nozzle 20.

In an alternative embodiment, as shown in figure 3, the drag flow interrupter 40 may, at a distal end thereof have a concave shape adjacent the outer channel outlet 38. This concave shape may promote a larger area of protective gas around the outflowing reactive gas thus resulting in an improved shielding of inner channel outlet 34 and outer channel outlet from oxidation gas.

In an embodiment, the transverse dimension of the drag flow interrupter 40 is at least 20% larger as the outer transverse dimension of the ring-shaped outer channel outlet 38.

A drag flow interrupter 40 with such outer dimensions effectively distances the location at which reactive gas and the oxidation gas start mixing from the inner channel outlet 34 and the outer channel outlet 38.

In an embodiment, the exhaust abatement apparatus 10 further comprises a protective gas source 44, which is fluidly connected to the outer channel inlet 36.

The protective gas source 44 may ensure a constant availability and delivery of the protective gas. The protective gas source 44 may e.g. be a vessel containing pressurized nitrogen (N2). Instead of a vessel, other protective gas sources 44 are possible as well, such a direct pipeline from a nitrogen producing apparatus. In an embodiment, the exhaust abatement apparatus 10 may further comprise a flammable gas source 46, and the central pipe 28 may further comprise an additional inner channel inlet 48, which is fluidly connected to the flammable gas source 46.

The flammable gas or fuel can be mixed with the exhaust gas before they are both supplied to the abatement chamber 16. Burning a flammable gas will heat up a non-flammable exhaust gas to thermally decompose a thermally-decomposable component contained therein. Harmful and other substances of an exhaust gas discharged from a semiconductor manufacturing process can produce dust particles which will be collected in the abatement box.

In an embodiment, of which an example is shown in figure 1, the abatement chamber 16 may comprise an abatement chamber gas inlet 50 for supplying oxidation gas to the abatement chamber 16. The exhaust abatement apparatus 10 may further comprise a gas pump 52 having a pump inlet 52a and a pump outlet 52b for promoting an upward gas flow in the abatement chamber 16. In the example shown in Fig. 1, the oxidation gas in the abatement chamber 16 may be air. The air may be supplied via the gas pump 52 of which the pump inlet 52a emanates in the environment containing the air and of which the pump outlet 52b is connected to a channel which is fluidly connected to the abatement chamber gas inlet 50. Alternatively, the gas pump 52 may be placed in the abatement chamber exhaust 18. In this alternative embodiment, the abatement chamber gas inlet may emanate in the environment so that air may be supplied to the abatement chamber 16, or, alternatively may be fluidly connected to an oxidation gas source, like a vessel containing oxidation gas.

The gas pump 52 in combination with an appropriately positioned abatement chamber exhaust 18 and abatement chamber gas inlet 50 may create a steady, preferably laminar gas flow in the abatement chamber 16 from the abatement chamber gas inlet 50 to the abatement chamber exhaust 18. The gas flow created by the gas pump 52 may ensure that sufficient oxidation gas is available for the reactive gas to be completely oxidized. Preferably, the flow speed of the gas in the abatement chamber 16 is low, so that any particles contained therein are not dragged along with the flow but have the chance to fall down so as to be collected on the bottom 12a of the abatement chamber housing 12.

In an embodiment, the abatement chamber exhaust 18 may be at a vertically higher level than the abatement chamber gas inlet 50. This creates a gas flow in the abatement chamber 16 in an upward direction. As a result of the oxidation or combustion of the reactive gas, solid particles 64 and product gasses may be formed, depending on the reactive gas and the oxidation gas in question. When the flow speed of the gas in the abatement chamber 16 is slow enough, the solid particles 64 will fall down and will accumulate at a bottom side 12a of the abatement chamber housing 12. In this way the solid particles 64 are separated from the gas flow and the solid particles 64 may be easily removed from the abatement chamber 16 and processed as waste.

In an embodiment, the abatement chamber 16 may have a height in the range of 0.5 m to 3 m and may has a cross section dimension in the range of 0.1 m to 1 m. With such dimensions, the gas flow speed in the abatement chamber 16 may be very low and the time which the particles have before they reach the abatement exhaust 18 may be so long that these particles are fallen due to gravity down before they have reached the abatement chamber exhaust 18. Additionally, the large dimensions of the abatement chamber 16 and the low gas flow speed prevailing therein reduces the occurrence of gas turbulence in the exhaust abatement chamber 16 so that gravity separation of solid reaction particles for the upward gas flow within the exhaust gas abatement chamber 16 is optimized. Even if particles are deposited on the housing walls 14, this has no influence on the gas flow speed in the abatement chamber 16. Further, due to the large volume of the abatement chamber 16, the exhaust abatement apparatus 10 allows to be operated for a long time without interruption for removing accumulated powder of collected particles.

The exhaust abatement apparatus 10 may further comprise a gas flow speed sensor 54 configured to detect a gas flow speed in the abatement chamber 16, and a controller 56 configured to control a speed of the gas pump 52 in dependence of the detected gas flow speed by the gas flow speed sensor 54.

By controlling the gas pump 52, the gas flow through the abatement chamber 16 may be kept sufficiently low to prevent undesired turbulence within the abatement chamber 16 while at the same time ensuring sufficient supply of air or, alternatively oxidation gas from the oxidation gas source so that there is always enough oxidation gas present to completely oxidize the reactive gas supplied via the inner channel outlet 38.

In an embodiment, the abatement chamber exhaust 18 may comprise a filter 58. The filter 58 may filter out any hazardous gas left in the gas mixture inside the abatement chamber 16 after oxidation of the reactive gas. Additionally or alternatively, the filter 58 may filter any solid particles which were able to reach the abatement chamber exhaust 18.

In an embodiment, the abatement chamber housing 12 may comprise a service opening 60 and a service panel 62 configured to selectively close off the service opening 60.

The service panel 62 facilitates access to the abatement chamber 16. The service panel 62 may have a closed position in which the service panel 62 closes off the service opening 60. The service panel 62 may also have an closed configuration, in which the service panel 62 is moved away from the service opening 60. Solid particles 64 formed by oxidation of the reactive gas may be accumulated at a bottom side 12a of the abatement chamber housing 12 by virtue of gravity separation. In the open configuration these solid particles 64 can be removed from the abatement chamber 16 via the service opening 60. Thus, it is preferable that the service opening 60 with the service panel 62 are adjacent the bottom side 12 of the abatement chamber housing 12.

The invention also relates to a method for abating reactive gasses. The method comprises: providing an exhaust abatement apparatus 10 according to the invention, providing an oxidation gas in the abatement chamber 16; supplying a reactive gas to the abatement chamber 16 via the inner channel outlet 34; supplying a protective gas to the abatement chamber 16 via the outer channel outlet 38 simultaneously with supplying the reactive gas to the abatement chamber 16; and interrupting a drag of flow of oxidation gas along the outer channel outlet 38 by means of the drag flow interrupter 40.

The effects and advantages of the method have been described in the summary section and these effects and advantages are inserted here by reference.

In an embodiment, the protective gas may be supplied parallel to the supplied reactive gas and the protective gas flow surround the reactive gas flow thus, at least initially shielding the reactive gas flow from the oxidation gas in the exhaust abatement chamber 16. The gasses supplied from the inner channel outlet 34 and the outer channel outlet 38 may be supplied substantially horizontal into the abatement chamber 16. Such parallel flows of the protective gas and the reactive gas minimize the initial mixing of the two gasses. Only after some travelling distance, the reactive gas and the protective gas start to mix with each other and even after that with the oxidation gas present in the abatement chamber 16. Thus, the formation of reaction products, which may be solid particles only takes place at a distance from the inner and outer channel outlets 34, 38 of the nozzle 20, thus preventing clogging of the nozzle outlets 34, 38. Additionally, because of the fact that the reaction gas is firstly diluted with the protective gas, the reaction between the reaction gas and the oxidation gas will be smooth resulting in a smaller particle size.

In an embodiment, the reactive gas may comprise a mixture of trimethylaluminum (TMA) and a carrier gas. Trimethylaluminum (TMA) is a well-known precursor in an atomic layer deposition (ALD) method.

In an embodiment, the protective gas may comprise nitrogen (N2). Nitrogen is a well-known inert gas, making it ideally suited as protective gas. Moreover, after use, nitrogen can be released into the atmosphere, because it occurs naturally. Approximately 80% of the air consists of nitrogen.

In an embodiment the oxidation gas comprises oxygen (O2). The oxidation gas may for example be air which may be withdrawn from the environment.

The various embodiments which are described above may be implemented independently from one another and may be combined with one another in various ways. The reference numbers used in the detailed description and the claims do not limit the description of the embodiments nor do they limit the claims. The reference numbers are solely used to clarify by referring to the non-limiting example in the figures.

- exhaust abatement apparatus - abatement chamber housing a - bottom side (of abatement chamber housing) - abatement chamber housing wall - abatement chamber - abatement chamber exhaust - nozzle - nozzle housing a - distal end (of nozzle housing) - outer channel - central axis - central pipe a - distal end (of central pipe) - inner channel - inner channel inlet - inner channel outlet - outer channel inlet - outer channel outlet - drag flow interrupter - outer pipe - protective gas source - flammable gas source - additional inner channel inlet - abatement chamber gas inlet - gas pump a - pump inlet b - pump outlet - air flow sensor - controller - air filter - service opening - service panel - solid particles