Patent Description:
In a device for film deposition as one of process steps when a semiconductor, a solar battery, a liquid crystal, or the like is manufactured, a process gas such as a silane (SiH<NUM>) gas is used in a vacuum chamber for generating a Si film.

A discharged gas (exhaust gas) after being used is exhausted to an outside of the vacuum chamber serving as a device for a semiconductor manufacturing process by a vacuum pump connected to the vacuum chamber. In most cases, such a discharged gas contains various toxic gases resulting from a film deposition step, such as the silane gas described above, tungsten hexafluoride (WF<NUM>), and dichlorosilane (SiH<NUM>Cl<NUM>). Accordingly, to an exhaust side of the vacuum pump, a detoxification device is connected to oxidize such a discharged gas and exhaust the discharged gas as a harmless gas.

This detoxification device comes in various types such as a combustion type and a plasma type. In the case of a combustion type detoxification device, for example, an oxidative reaction in which the discharged gas is burned to react with air (oxygen) is caused to change the toxic gas to a harmless gas.

<FIG> is a schematic diagram illustrating a configuration of each of an inlet nozzle <NUM> and a combustor (combustion furnace) <NUM> in an existing detoxification device <NUM>. Such a detoxification device is for example known from <CIT>.

As illustrated in the drawing, an insulator <NUM> serving as an insulating material is provided adjacent to the combustor <NUM>. An inlet nozzle <NUM> having a length corresponding to a thickness of the insulator <NUM> is provided in the insulator <NUM> to extend therethrough. The detoxification device <NUM> is configured such that an exhaust gas is transferred to the combustor <NUM> through the inlet nozzle <NUM>.

When an exhaust gas (hereinafter referred to as the metallic exhaust gas) containing a metal (e.g., titanium or tungsten hexafluoride) is transferred to the combustor <NUM> through the inlet nozzle <NUM>, under radiation of heat from the combustor <NUM>, a reductive reaction occurs at a tip portion (portion adjacent to the combustor <NUM>) of the inlet nozzle <NUM>. Consequently, the exhaust gas is precipitated as a metallic product to be gradually deposited as a metallic product X with time.

A phenomenon in which the metallic product is precipitated is caused by a high temperature and a supply of electrons (supply from the inlet nozzle <NUM> made of stainless steel).

The metallic product X has an extremely high hardness and, once the metallic product X is deposited, it is difficult to remove the metallic product X by using a scraper <NUM> (see <FIG>, a device for scraping off a deposit). Specifically, as illustrated in <FIG>, the metallic product X is so solidly fixed as to stop movement of the scraper <NUM>. When this state is left untreated, a flow path is gradually clogged.

As a result, a problem of a shorter maintenance (overhaul) cycle for the detoxification device <NUM> arises.

An object of the present invention is to provide an inlet nozzle capable of reducing an amount of a deposit of an adhering metallic product and elongating a maintenance cycle and a detoxification device including the inlet nozzle.

The invention provides a detoxification device according to claim <NUM>.

The invention claimed in claim <NUM> provides the detoxification device according to claim <NUM> wherein the inlet nozzle is formed of an insulating material.

According to the present invention, it is possible to provide the inlet nozzle using the metal precipitation inhibiting structure provided therein to reduce an amount of a deposit of the metallic product adhering to a tip portion of the inlet nozzle and elongate a maintenance cycle as well as a detoxification device including the inlet nozzle.

From each of inlet nozzles <NUM> according to the present embodiment, a portion adjacent to a combustor <NUM>, i.e., a portion to which a metallic product adheres to be deposited thereon is cut (removed) in advance. Consequently, in the portion, an insulator <NUM> made of a ceramic material is exposed (metal precipitation inhibiting structure). Since the ceramic material supplies a small number of electrons, even when the insulator <NUM> is exposed to heat from the combustor <NUM> to reach a high temperature, a reductive reaction is less likely to occur.

Accordingly, even when a metallic exhaust gas is allowed to flow, it is possible to inhibit the metallic exhaust gas from being precipitated as the metallic product and gradually deposited with time.

As a result, it is possible to reduce a deposit adhering to the portion adjacent to the combustor <NUM> and consequently elongate a maintenance cycle for a detoxification device <NUM>.

Referring to <FIG>, a detailed description will be given below of each of preferred embodiments of the present invention.

<FIG> is a schematic diagram illustrating a relationship between each of the inlet nozzles <NUM> and the combustor <NUM> in the detoxification device <NUM> according to the present embodiment.

From each of the inlet nozzles <NUM> according to the present embodiment, a portion close to the combustor (detoxification chamber) <NUM> of the inlet nozzle <NUM> is cut (removed) to shorten the inlet nozzle <NUM> by a given length. In other words, a portion of the inlet nozzle <NUM> on which, when the metallic exhaust gas is allowed to flow, the metallic exhaust gas is normally precipitated as the metallic product to be gradually deposited with time is removed in advance.

Consequently, a portion of the insulator <NUM> adjacent to the combustor <NUM> is exposed to a path for the exhaust gas (exposed portion W). The insulator <NUM>, which is made of a ceramic material, supplies a smaller number of electrons than that of electrons supplied from the inlet nozzle <NUM> made of a stainless steel. As a result, even when the metallic exhaust gas is allowed to flow, it is possible to prevent the metallic exhaust gas from being precipitated as the metallic product and solidly adhering to the place.

Due to this configuration, even when the exposed portion W of the insulator <NUM> is exposed to radiation of heat from the combustor <NUM>, a reductive reaction is less likely to occur in the exposed portion W of the insulator <NUM> to prevent the metallic exhaust gas from being precipitated as the metallic product and being gradually deposited with time.

As a result, it is possible to reduce the deposit adhering to the portion adjacent to the combustor <NUM> and consequently elongate a maintenance cycle for the detoxification device <NUM>.

<FIG> is a diagram illustrating an example of a schematic configuration for illustrating a system layout in which the detoxification device <NUM> including the inlet nozzles <NUM> according to the embodiment of the present invention is disposed.

In the embodiment, it is assumed by way of example that the detoxification device <NUM> in which the inlet nozzles <NUM> are disposed is a combustion type detoxification device. However, the detoxification device <NUM> in which the inlet nozzles <NUM> according to the embodiment of the present invention are disposed is not limited to the combustion type. Instead, the inlet nozzles <NUM> according to the present embodiment can also be disposed in, e.g., the detoxification device <NUM> of a heater type or a gasoline-engine type or the like.

A processing device (processing chamber) <NUM> disposed in a clean room <NUM>, such as a wafer deposition device, is connected to a dry pump <NUM> via a vacuum pipe <NUM>. The dry pump <NUM> is further connected to the detoxification device <NUM> via an exhaust pipe <NUM>.

A casing forming a housing of the detoxification device <NUM> has a substantially cylindrical shape and has an upper end configured to have an inlet head <NUM> (<FIG>) serving as a lid portion. The casing need not necessarily have the substantially cylindrical shape as long as the casing is configured to have an inner space isolated from an outside thereof.

<FIG> is a diagram illustrating an example of a schematic configuration of the detoxification device <NUM> in which the inlet nozzles <NUM> according to the embodiment of the present invention are disposed. Arrows G in the drawing represent flows of the exhaust gas containing a gas to be detoxified.

The exhaust gas containing a toxic gas exhausted from the processing device <NUM> passes through the vacuum pipe <NUM>, goes through the dry pump <NUM>, and passes through the exhaust pipe <NUM> to be delivered to the detoxification device <NUM>.

Then, an inlet three-way valve <NUM> divides the exhaust gas into an exhaust gas to be exhausted into a combustible exhaust duct and an exhaust gas to be transferred to the combustor (combustion furnace) <NUM>.

The exhaust gas passes through an inlet pipe <NUM> and then goes through the inlet head (gas inlet port) <NUM> to be delivered to the combustor <NUM>.

The combustor <NUM> is a space in which the gas to be detoxified containing the toxic gas is to be subjected to combustion processing, and a temperature in the combustor <NUM> is approximately around <NUM>. In the inlet head <NUM>, the insulator <NUM> is disposed for heat insulation and, in the insulator <NUM>, the inlet nozzles <NUM> are embedded.

The detoxification device <NUM> according to the present embodiment includes the combustor <NUM> serving as the combustion furnace and a quench <NUM> serving as an exhaust gas cooler.

Into the combustor <NUM>, a gas to be processed such as a combustible gas or a cleaning gas exhausted from a Chemical Vapor Deposition (CVD) device for a semiconductor manufacturing process, which is not shown, via the vacuum pump <NUM> such as the dry pump is introduced, via the inlet pipe <NUM>, from the inlet head <NUM> disposed at an upstream end of the combustor <NUM> and serving as the inlet port of the detoxification device <NUM>. The combustor <NUM> combusts and decomposes the introduced gas to be processed at a high temperature.

Examples of the combustible gas include a colorless toxic silane (SiH<NUM>) gas, a colorless (yellow) toxic highpressure tungsten hexafluoride (WF<NUM>) gas, and dichlorosilane (SiH<NUM>Cl<NUM>). Examples of the cleaning gas include ammonium (NH<NUM>).

In the present embodiment, the exhaust gas exhausted from the vacuum pump and introduced into the combustor <NUM> from the inlet head <NUM> is combusted and decomposed by the combustor <NUM>. By the combustion/decomposition, the toxic gas contained in the exhaust gas is detoxified.

An exhaust gas resulting from the combustion/decomposition is cooled from about <NUM> to about <NUM> by the quench <NUM> serving as the gas cooler. Note that, for the cooling of the exhaust gas, cooling water is used.

Then, the cooled exhaust gas and fine particle dust resulting from the combustion/decomposition are exhausted from an exhaust port (downstream end) of the combustor <NUM> to be introduced into a packed tower <NUM> serving as a wet detoxifier through a cyclone <NUM> serving as a powder remover. A water-soluble gas such as hydrogen fluoride (HF) or hydrogen chloride (HCl) is dissolved in this portion. Then, the exhaust gas is transferred to an acid exhaust duct to be exhausted.

Note that, in the present embodiment, each of the cyclone <NUM> and the packed tower <NUM> is formed of polypropylene.

<FIG> are diagrams for illustrating a periphery of the inlet head <NUM> in the detoxification device <NUM> including the inlet nozzles <NUM> according to the embodiment of the present invention.

<FIG> illustrates an overall view of a portion α (the inlet pipe <NUM>, the inlet head <NUM>, the combustor <NUM>, and a scraper <NUM> described later) in <FIG>, which is a cross-sectional view along an axial direction. <FIG> illustrates a view obtained by viewing the portion α (the inlet nozzles <NUM> and the inlet head <NUM>) in <FIG> from an upstream side in the flows of the exhaust gas.

In the present embodiment, by way of example, the inlet head <NUM> is configured to be include four inlet holes <NUM> in which the inlet nozzles <NUM> are disposed. However, the number of the inlet holes <NUM> can appropriately be changed to <NUM>, <NUM>, or the like as required.

Note that, by way of example, a material of the inlet head <NUM> according to the embodiment of the present invention is preferably stainless steel in terms of heat resistance and workability.

In each of the inlet nozzles <NUM>, the scraper <NUM> for removing a deposit adhering to a downstream end (closer to the combustor <NUM>) of the inlet nozzle <NUM> is deposited.

When the exhaust gas is allowed to flow, the deposit of the precipitated product is scraped off by the scraper <NUM> to be removed. However, the product derived from the metallic exhaust gas has an extremely high hardness and, once deposited, the product is extremely hard to remove.

Note that, in the present embodiment, the scraper <NUM> is configured in the form of an elastic body (spring), but the configuration of the scraper <NUM> is not limited thereto. For example, the scraper <NUM> may also be configured in the form of a rod, a blade, or a paddle.

<FIG> are diagrams for illustrating each of the inlet nozzles <NUM> according to the embodiment of the present invention.

<FIG> is a diagram illustrating a cross section of each of the inlet nozzles <NUM> along the axial direction. <FIG> is a diagram obtained by viewing the inlet head <NUM> in which the inlet nozzles <NUM> are disposed from below (from a downstream side when the exhaust gas flows). The inlet nozzle <NUM> has a lower end thereof adjacent to the combustor <NUM>.

As described above, the material of the inlet nozzles <NUM> according to the present embodiment is stainless steel. Instead, the material of the inlet nozzles <NUM> according to the present embodiment may also be Inconel (registered trademark), which is a nickel-base superalloy, or hastelloy (metal precipitation inhibiting structure).

Each of the inlet nozzles <NUM> according to the present embodiment is a component that provides communication between the inlet pipe <NUM> and the inlet head <NUM> in the detoxification device <NUM>, which is substantially a casing having an inner void and includes a flange portion <NUM>, a casing side portion <NUM>, a cut surface <NUM>, a (former bottom portion <NUM>), and the like.

The flange portion <NUM> is located in an upper half of the inlet nozzle <NUM> in the axial direction (i.e., on the upstream side of a flowing gas) to be fitted into the inlet pipe <NUM>.

The casing side portion <NUM> forms a side surface of the inlet nozzle <NUM>, which is a cylindrical casing in the present embodiment and fitted into any of the inlet holes <NUM> provided in the inlet head <NUM>.

By way of example, each of the inlet nozzles <NUM> according to the present embodiment is configured such that a length (before cutting) L1 of the entire inlet nozzle <NUM> in the axial direction is about <NUM> millimeters, a length L2 of a cut portion is <NUM> millimeters, and a length L4 of the flange portion <NUM> in the axial direction is <NUM> millimeters. Accordingly, a length L3 of the inlet nozzle <NUM> in the axial direction after cutting is <NUM> millimeters. The length (before cutting) L1 of the entire inlet nozzle <NUM> in the axial direction corresponds to a thickness of the insulator <NUM> in the axial direction in <FIG>. Consequently, the exposed portion W of the insulator in <FIG> has an axial length of <NUM> millimeters.

The length of the cut portion in the present embodiment corresponds to a portion on which, when the metallic exhaust gas is allowed to flow, the metallic exhaust gas is precipitated as the metallic product to be deposited. In other words, the portion of the inlet nozzle <NUM> close to the combustor <NUM> which receives a large amount of heat from the combustor <NUM> is cut in advance. The length of the cut portion is set appropriately depending on such conditions as a type of the metallic exhaust gas allowed to flow and a temperature of the combustor <NUM>.

However, cutting off fifty percent or more of the inlet nozzle <NUM> is not desirable because a function of the inlet nozzle <NUM> serving as a guide for the exhaust gas may be disturbed. In the present embodiment, the length of the cut portion preferably accounts for about <NUM>% to <NUM>%, or more preferably about <NUM>%±<NUM>-<NUM>% of the total pre-cutting length of the inlet nozzle <NUM>.

Note that, even when the inlet nozzle <NUM> is cut, a portion thereof close to the cut surface <NUM> still receives an amount of heat from the combustor <NUM>. However, since the portion close to the cut surface <NUM> is farther away from the combustor <NUM> than the former bottom portion <NUM> which used to be a bottom surface of the inlet nozzle <NUM>, the amount of the received heat decreases to be able to inhibit the generation of the metallic product.

By way of example, each of the inlet nozzles <NUM> according to the embodiment of the present invention is configured such that an outer diameter d1 of the flange portion <NUM> of the inlet nozzle <NUM> is <NUM> millimeters, an inner diameter (inner diameter of an upper portion of the casing of the inlet nozzle <NUM>) d2 of the flange portion <NUM> is <NUM> millimeters, and an outer diameter d3 of the casing side portion <NUM> is <NUM> millimeters.

Due to the configuration described above, in the detoxification device <NUM> in which the inlet nozzles <NUM> according to the present embodiment are disposed, the exhaust gas (metallic exhaust gas) introduced from the inlet pipe <NUM> passes through the inlet nozzles <NUM> to be transferred to the combustor <NUM>. In addition, since a lower end portion of each of the inlet nozzles <NUM> is shortened, the exhaust gas (metallic exhaust gas) is allowed to flow, while being kept in contact with the exposed portion W of the insulator <NUM>, to flow into the combustor <NUM>.

Note that an inner surface (portion in contact with the metallic exhaust gas) of the inlet nozzle <NUM> is preferably made of a material as smooth as possible or in a condition as smooth as possible. When the surface of the inlet nozzle <NUM> is smooth, the metallic product is less likely to adhere thereto or, even when the metallic product adheres to the surface of the inlet nozzle <NUM>, the metallic product easily peels away.

In a second embodiment, the inlet nozzles <NUM> made of an insulating material (metal precipitation inhibiting structure) are used. By producing the inlet nozzles <NUM> of the insulating material, electrons supplied therefrom are reduced, and the reductive reaction is less likely to occur in the metallic exhaust gas. As a result, it is possible to inhibit the metallic product from being deposited.

However, the tip portion of each of the inlet nozzles <NUM>, which is adjacent to the combustor <NUM>, is heated to a considerably high temperature, and therefore a material having a high heat resistance is desirable.

Accordingly, a material to be used preferably has an insulating property, a heat resistance, and a spreadability in consideration of workability.

Specific examples of the material include free-machining ceramics (machinable ceramics).

As required, the embodiments of the present invention may also be configured to be combined with each other.

Claim 1:
A detoxification device (<NUM>) comprising:
a detoxification chamber (<NUM>);
an insulator (<NUM>) provided adjacent to the detoxification chamber; and
an inlet nozzle (<NUM>) embedded in the insulator to guide an exhaust gas to be detoxified to the detoxification chamber,
wherein the inlet nozzle (<NUM>) defines an axial direction and the insulator (<NUM>) is made of a insulating material thickness (L1) in the axial direction;
characterised in that a portion of the inlet nozzle (<NUM>) adjacent to the detoxification chamber has a length (L3) in the axial direction set shorter by a predetermined length (L2) in the axial direction than the thickness (L1) of the insulating material to expose a portion (W) of the insulator (<NUM>), wherein the predetermined length (L2) corresponds to a portion of the inlet nozzle (<NUM>) on which a metallic product is deposited when the exhaust gas which is a metallic exhaust gas is allowed to flow in a state before the inlet nozzle is shortened.