Method for treating exhaust gas components, and exhaust gas treatment system

Abstract

The invention relates to a method (100) for treating components of an exhaust gas (1). The method (100) has the steps of: S2 generating surface-active dielectric barrier discharges (2), hereinafter referred to as S-DBD, S4 bringing the exhaust gas (1) into contact with the generated S-DBD 2, and S5 converting halogen-containing exhaust gas components into reaction products (3) by means of the S-DBD2. The invention further relates to an exhaust gas treatment system (6) for treating components of an exhaust gas (1), to a process installation (15), and to a method for producing an exhaust gas treatment system.

Description

[0001] Methods for treating exhaust gas components and exhaust gas treatment systems

[0002] The invention relates to a method for treating exhaust gas components, an exhaust gas treatment system, a process plant and a method for manufacturing an exhaust gas treatment system.

[0003] Various industrial processes generate exhaust gases contaminated with pollutants. Before being released into the environment, these pollutants must be largely removed to minimize environmental impact. Particularly in the semiconductor industry and related applications such as CVD (chemical vapor deposition) or plasma etching processes, exhaust gases are produced that are contaminated with environmentally relevant gaseous pollutants such as carbon hexafluoride (C₂F₆), tetrafluoromethane (CF₄), sulfur hexafluoride (SF₆), octafluoropropane (CsF₆), and others. Furthermore, the exhaust gases requiring treatment may contain all types of perfluorinated chemicals (PFCs).

[0004] The conversion of the aforementioned pollutants using burner scrubbers with combustion chambers is known from the prior art. These combustion chambers are generally operated with natural gas and oxygen or with DC (direct current) plasma torches (electric arcs). A wet scrubber is usually installed downstream to remove the reaction products of the introduced gases from behind the combustion chamber. Combustion occurs through the generation of a flame wall through which the pollutant-laden exhaust gases must pass. As the pollutant-laden exhaust gases pass through the flame wall, the pollutants are oxidized by the action of the oxygen and / or, depending on the type of gas, "cracked." Furthermore, a reaction with hydrogen atoms contained in the fuel gas can occur; for example, fluorine can react with the hydrogen atoms in the fuel gas to form HF.

[0005] An example of such an exhaust gas purification device is known from WO 96 / 23173. This device contains a combustion chamber with a burner to which fuel gas, such as hydrogen and oxygen or air, as well as the process exhaust gas to be decomposed, are supplied. Above the combustion chamber is a scrubbing chamber with a spray device for atomizing the sorbent. The combustion chamber is located within an outer tube and is bounded by an inner tube, the outer tube also enclosing the scrubbing chamber located above the combustion chamber.

[0006] The reaction products formed in the combustion chamber are routed between the inner and outer pipes into the wash chamber and from there into the ambient air via an extraction system.

[0007] Such an exhaust gas purification device can treat a wide variety of gases, such as SiH4, PH3, B2H6, TEOS (tetraethoxysilane) from CVD processes, C2F6, CF4, CH3F, Ch, BCI3 from dry etching and other processes, with very high efficiency. The prerequisite is that the parameters of the exhaust gas purification system are specifically tailored to the type and quantity of gases or vapors to be purified, ensuring that combustion or thermal decomposition occurs through the combustion of fuel gas and oxygen with excess oxygen.

[0008] The disadvantages of the known methods are the high energy consumption required to reach the necessary temperatures and the associated costs. Furthermore, the high temperatures promote the formation of nitrogen oxides, which are also pollutants and should be removed from the exhaust gas.

[0009] Against this background, the object of the invention is to provide a method and a device for exhaust gas treatment with which the aforementioned disadvantages can be at least partially eliminated. An increase in energy efficiency and a reduction in nitrogen oxide formation would be desirable.

[0010] This problem is solved by the subject matter of the independent claims. The dependent claims concern specific configurations.

[0011] A key concept of the invention is to treat components contained in exhaust gas, e.g., pollutants, by means of surface-active dielectric barrier discharges, also known as S-DBD (surface-dielectric barrier discharge). Such discharges can be generated and operated at near room temperature, thus reducing energy consumption compared to prior art exhaust gas treatment and purification methods. Furthermore, due to the lower temperature, fewer nitrogen oxides are formed, so that nitrogen oxide removal from the exhaust gas is less necessary or can even be eliminated entirely.

[0012] S-DBDs contain high-energy electrons that can break up exhaust gas components through electron impact processes. This process is called kinetic dissociation (by electron impact), in contrast to the thermal dissociation or decomposition mentioned above. Furthermore, highly reactive species, such as ozone, can form, which can be used for further oxidation and / or reduction, resulting in the formation of reaction products that are less harmful and / or absorbable. For example, CF4 can be broken down into CF2 and two fluorine atoms, with CF2 reacting further with ozone to form COF2. This can lead to the formation of CO2. If hydrogen is also available, HF can be formed, which, as mentioned above, can react with NaOH in the scrubber to form NaF, so that fluorine is bound as a salt and dissolved in the water.

[0013] A first aspect of the invention relates to a method for treating exhaust gas components, for example pollutants in an exhaust gas, in particular exhaust gases from process plants for semiconductor manufacturing, such as CVD, LP-CVD, plasma-CVD, plasma etching or similar process plants.

[0014] The term "exhaust gas" here generally refers to a gas or a mixture of gases that is generated, for example, during the aforementioned processes and / or used in these processes, e.g., as a carrier gas. The term "exhaust gas component" refers to components of the exhaust gas that are preferably in gaseous form. Exhaust gas components in this sense can be, in particular, pollutants, i.e., components of the exhaust gas that are, for example, environmentally harmful and / or toxic and must not or should not be released into the environment untreated. Exhaust gas components that are not pollutants in this sense can also be treated within the framework of the proposed process, for example, for the recovery of chemicals.

[0015] The proposed method involves generating surface-active dielectrically hindered discharges, hereinafter referred to as S-DBD. DBDs are alternating voltage gas discharges in which at least one of the electrodes is electrically isolated from the gas space by galvanic isolation using a dielectric. In contrast to V-DBD (Volume-Dielectric Barrier Discharge), where discharges form perpendicular to the dielectric barrier, the discharges and plasma in S-DBD, macroscopically speaking, propagate along the surface of the dielectric barrier and parallel to this surface. Microscopically, however, the plasma forms perpendicular to the surface of the dielectric barrier, creating characteristic vortices that "draw" the exhaust gas through the plasma.

[0016] S-DBD can be used to generate a cold plasma, a mixture of particles consisting of ions, free electrons, and possibly neutral atoms or molecules, whose temperature is not elevated, or only slightly elevated (e.g., by a few tens of Kelvin), compared to the ambient temperature. The cold plasma can, for example, have a temperature between 20 °C and 200 °C, or between 20 °C and 80 °C.

[0017] The exhaust gas to be treated is then brought into contact with the generated S-DBD, for example by passing the exhaust gas stream through an area where S-DBDs are formed.

[0018] Subsequently, halogen-containing exhaust gas components, e.g., fluorine- and / or chlorine-containing exhaust gas components (i.e., exhaust gas components with fluorine or chlorine atoms), are converted into reaction products using the S-DBD. The conversion can occur directly, i.e., through interaction of the S-DBD with the exhaust gas components, or indirectly, i.e., through the formation of a plasma and interaction of the plasma with the exhaust gas components. The inventors hypothesize that the reaction in the proposed process is initiated by fast electrons, i.e., that the dissociation energy is supplied to the exhaust gas components to be treated by fast electrons. The exhaust gas is introduced directly into the high-energy discharge zone via turbulence and comes into direct contact with the highly accelerated electrons, which can have energies exceeding 1 eV, corresponding to temperatures above 10,000 K.

[0019] In this context, "halogen" refers to elements of group 17 of the periodic table, specifically fluorine, chlorine, bromine, and iodine. Optionally, other, non-halogenated exhaust gas components can also be converted into reaction products. For example, the exhaust gas components to be treated can be selected from a group comprising Si H4, PH3, B2H6, TEOS, C2F6, C3F8, CF4, CH3F, Ch, BCh, SFe, and NF3, with at least one halogenated exhaust gas component being treated.

[0020] The reaction products obtained can be further processed, as will be explained below, or possibly released directly into the environment.

[0021] The inventors of the present invention have surprisingly discovered that not only can highly reactive exhaust gas components be converted into suitable reaction products using S-DBD, but that, contrary to prevailing opinions, S-DBD can also effect the conversion of weakly reactive exhaust gas components, such as halogenated and, in particular, fluorinated exhaust gas components, despite its low energy density. In other words, the actual electron density of S-DBD is too low for the conversion of halogenated exhaust gas components. However, the voltage pulses generate plasma vortices, thus enabling the conversion of the halogenated exhaust gas components contrary to expectations. The shorter the voltage pulses, the more efficient the formation of the vortices and the associated conversion of the exhaust gas components.

[0022] The steps of the proposed procedure can be carried out in the order mentioned, but depending on need and possibility, they can also be carried out simultaneously, overlapping in time or in a different order.

[0023] The use of S-DBDs for exhaust gas treatment offers the advantage of significantly lower energy consumption. For example, suitable S-DBDs can be generated with a power output of only 500 W, whereas generating a comparably effective DC plasma would require 15–20 kW. Furthermore, nitrogen oxide formation is considerably lower, potentially eliminating the need for subsequent nitrogen oxide treatment.

[0024] Depending on the design, the halogenated exhaust gas components may contain fluorine.

[0025] Due to the high electronegativity of fluorine, fluorine-containing exhaust gas components can often only be treated inadequately using conventional methods. The use of S-DBD, on the other hand, has proven advantageous in the treatment of fluorine-containing exhaust gas components, as it allows for the recovery of further processable reaction products.

[0026] According to further design variants, the halogenated exhaust gas components can be perhalogenated, e.g. perforated and / or perchlorinated, compounds.

[0027] The term "perhalogenated compound" refers to organic chemical compounds in which the hydrogen atoms on at least one carbon atom or heteroatom, e.g. nitrogen, sulfur or phosphorus atom, preferably on all carbon or heteroatoms, have been completely replaced by halogen atoms.

[0028] The perhalogenated compound can, for example, be selected from a group including carbon hexafluoride, tetrafluoromethane, sulfur hexafluoride, nitrogen trifluoride, and octafluoropropane. In other words, using the proposed method, one or more of the aforementioned compounds, in any combination, can be converted from halogenated exhaust gas components to reaction products via S-DBD.

[0029] Perforated compounds exhibit high persistence, partly due to the high reactivity of fluorine, and should therefore not be released into the environment. Furthermore, their low chemical reactivity makes them difficult to convert into suitable reaction products. The proposed method advantageously enables the treatment of perfluorinated compounds with high energy efficiency and low nitrogen oxide formation, as well as their conversion into chemical compounds such as HF, whose disposal or further use is simpler compared to the perforated compounds themselves.

[0030] According to further embodiments, the process can involve the addition of a hydrogen (H) and / or oxygen (O) donor.

[0031] For example, water (e.g., in the form of water vapor and / or gaseous water), hydrogen, oxygen, and / or ozone can be added to the exhaust gas as a hydrogen and / or oxygen donor. Of course, different hydrogen and / or oxygen donors can also be used.

[0032] The addition of the H and / or O donor to the exhaust gas can preferably take place after the exhaust gas has come into contact with the generated S-DBDs. This allows radicals generated during the reaction using S-DBDs to be oxidized or reduced, resulting in reaction products that are, for example, easier to process further, e.g., more readily absorbable.

[0033] Furthermore, the addition of the H and / or O donor can contribute to the suppression of reverse reactions of the dissociated halogenated exhaust gas components. A possible reaction mechanism, for example in the treatment of nitrogen trifluoride, can be as follows: e⁻ + NF₃ → NF₂ + F + e⁻

[0034] In a subsequent step, NF2 can then be broken down into NF and F. The resulting NF2 and NF radicals react preferentially in the presence of O donors (O / O2) to form NO and NO2 respectively, while free F atoms can be bound to HF via H donors (H2O / H2).

[0035] F + H2O —> HF + OH

[0036] H + F HF

[0037] Additionally, NF X -Species are further converted to NOx (NO, NO2) and HF via successive oxidation and hydrolysis steps. This plasma-induced cascade mechanism differs fundamentally from oxidation pathways of volatile organic compounds (VOCs), which are important, for example, in the treatment of paint fumes.

[0038] The use of a hydrogen donor, i.e., performing exhaust gas treatment under reductive conditions, is particularly advantageous because the exhaust gas components to be treated contain halogens, and in particular may also contain fluorine, and halogens, especially fluorine, have a high electronegativity. Therefore, while treatment under purely oxidative conditions, e.g., with O₂ or O₃, can form oxidation products such as COF₂ or CF₂O, the excess fluorine remains in the form of reactive fluorine radicals, which, without a bonding partner, can lead to the (re)formation of per- and / or polyfluorinated chemicals.

[0039] According to further embodiments, the process can be designed so that the conversion of the halogen-containing exhaust gas components is catalyzed. In other words, a catalyst material, e.g., a gold- and / or platinum-containing material, a material consisting of gold or platinum, or a catalyst based on CuO, ZnO, and / or Al₂O₃, can be used to accelerate the conversion of the halogen-containing exhaust gas components and / or to selectively form certain reaction products.

[0040] The catalyzed reaction can further improve the energy efficiency and / or the destruction and removal efficiency (DRE) of the exhaust gas treatment.

[0041] Preferably, a catalyst based on CuO, ZnO, and / or AhCh can be used. Particularly preferred is a doped or undoped AhCh-based catalyst. Such catalysts are characterized by high selectivity and high destruction and removal efficiency. Doping, understood here as the targeted introduction of foreign atoms to modify the properties of the catalyst material, can contribute to a longer lifetime or other improved properties compared to an undoped catalyst.

[0042] In particular, it can be provided that the catalysis takes place directly during the contact of the halogen-containing exhaust gas components with the S-DBD. For example, it can be provided that the substrate plate on which the plasma is ignited can itself serve as a catalyst or can be coated or doped with a catalyst. For example, it is possible not to coat the substrate completely with the catalyst, but only to provide it with the catalyst in certain areas or sections, preferably outside the conductive structure. For example, the substrate can be coated with a material, preferably with a material that has a high permittivity e. r exhibits, for example, barium titanate. This material can then be or become doped with the catalyst.

[0043] This allows the distance between the plasma and the catalyst to be reduced, which contributes to increased synergy between catalysis and plasma treatment and can thus improve the efficiency and / or effectiveness of exhaust gas treatment. Furthermore, this can broaden the selection of usable substrate materials, as substrate materials with lower material-dependent permittivity values ​​(e) can also be used. r can be used.

[0044] Since the reactive species generated in the plasma are often very short-lived, the direct presence of the catalyst in the plasma region increases the reactivity of such species. This creates synergistic effects that are lost with downstream catalysts because many radicals recombine before reaching the catalyst.

[0045] Additionally, the plasma can continuously regenerate the catalyst. Such regeneration can include, for example, the removal of impurities from catalyst surfaces. Furthermore, the plasma can excite the substrate surface in a way that may be beneficial to the desired reactions, such as by increasing the oxygen content.

[0046] Integrating the catalyst into the plasma can advantageously lead to a significant improvement in exhaust gas treatment results, particularly in exhaust gas purification. The dissociation of stable molecules from halogenated exhaust gas components is significantly enhanced by synergistic effects between the S-DBD and the catalytic surface, resulting in higher conversion rates and lower emissions.

[0047] Operating temperatures and improved selectivity towards stable end products, such as CO2, HF, can be achieved.

[0048] According to further embodiments, the process can involve the absorption of the reaction products.

[0049] For example, the reaction products formed can be completely or partially bound by an absorbent, e.g. water, sodium or potassium hydroxide solution, or iron oxide in dry form.

[0050] Absorption allows the reaction products formed to be easily removed from the exhaust gas stream and, if necessary, reused. The exhaust gas stream, now free of reaction products, can be released into the environment as exhaust air.

[0051] According to further embodiments, the process can include the introduction of exhaust gas from a process chamber. For example, the exhaust gas can be removed from a process chamber by means of a vacuum pump and then fed to the reactor for exhaust gas treatment. This means that the exhaust gas stream can be generated by the vacuum pump from a process chamber where low pressure prevails and then fed at a higher pressure, e.g., ambient pressure, to a reactor where the halogen-containing exhaust gas components are converted by S-DBD. Optionally, several vacuum pumps arranged in series and / or parallel with respect to the exhaust gas flow direction can be provided to remove the exhaust gases from one or more process chambers. The exhaust gases from several vacuum pumps can optionally be combined before the exhaust gas is brought into contact with the generated S-DBD.

[0052] The vacuum pump(s) allow for a uniform exhaust gas flow with an adjustable volume flow rate. This enables adaptation to the generated S-DBDs, thus facilitating efficient conversion of the exhaust gas components.

[0053] Another aspect of the invention relates to an exhaust gas treatment system for treating exhaust gas components. The exhaust gas treatment system comprises a reactor with a reactor chamber. A dielectrically insulated substrate is arranged in the reactor chamber, on which an electrically conductive structure for generating surface-active dielectrically hindered discharges is formed, e.g., printed.

[0054] The proposed exhaust gas treatment system can be used, for example, to carry out the exhaust gas treatment process described above. Therefore, the above explanations of the process also serve to describe the exhaust gas treatment system. The advantages of the process are thus directly linked to the exhaust gas treatment system.

[0055] "Dielectrically insulated" means that the substrate can be penetrated by an electrically insulated field, whereby only a current so small as to maintain the plasma can flow. Preferably, the dielectrically insulated substrate has a relative permittivity of at most 20, more preferably at most 10. The dielectrically insulated substrate can, for example, be a ceramic material, i.e., an inorganic non-metallic material, or consist of a ceramic material. For example, the substrate can consist of a material with at least 96% Al₂O₃.

[0056] The substrate can preferably be plate-shaped, more preferably as a flat plate. However, other substrate geometries are also possible, e.g., curved substrates, for example, in a cylindrical shape. Plate-shaped substrates have the advantage of simple manufacturing and the possibility of space-saving arrangement in the reactor. Furthermore, S-DBDs can be produced uniformly. A "plate" or "plate-shaped" substrate is understood to be one whose lateral dimensions, and thus, for example, the area of ​​the top and bottom surfaces, are significantly larger than its thickness, and whose thickness is essentially the same across the entire substrate. In the case of a flat plate, its top (front) and bottom (back) surfaces are planes.

[0057] The electrically conductive structure incorporates or consists of an electrically conductive material. The electrically conductive structure can be printed onto the substrate, for example, using a screen printing process. For instance, the electrically conductive material can have a MoMn layer with a thickness between 5 and 18 pm. The MoMn layer can be formed using the molybdenum-manganese process, in which a paste consisting of molybdenum and manganese powder and an organic binder is applied to the substrate, for example, using screen printing or a brush, and then treated with hydrogen at high temperature.

[0058] A nickel layer, e.g., with a thickness between 2 and 6 pm, can be applied to the MoMn layer to prevent oxidation of the underlying MoMn layer. MoMn and Ni layers have the advantage of being cost-effective and being deposited onto a substrate using printing processes.

[0059] In this context, "structure" means that the electrically conductive material is structured, i.e., formed on the substrate in a predefined arrangement. For example, the electrically conductive structure can have a square pattern and / or a honeycomb pattern, i.e., hexagons with each side in common.

[0060] The structure can be formed in particular by interconnected conductor tracks that are connected to contacts for electrical contacting.

[0061] The dielectrically insulated substrate and the electrically conductive structure formed on it serve to generate surface-active dielectrically hindered discharges. For this purpose, an alternating electrical voltage is applied to the conductive structure as the first electrode and to a second electrode, which is also arranged on or attached to the dielectrically insulated substrate, preferably on the opposite surface of the substrate.

[0062] The exhaust gas treatment system may also include an exhaust gas supply device designed to feed the exhaust gas to the reactor. Furthermore, an exhaust gas discharge device may be provided to remove the treated exhaust gas, along with the reaction products formed, from the reactor. The exhaust gas supply device and / or exhaust gas discharge device may, for example, be designed as pipelines.

[0063] According to various design variants, said electrically conductive structures can be formed on opposite surfaces of the dielectrically insulated substrate, for example on a top or front and a bottom or back of a plate-shaped substrate.

[0064] This has the advantage that S-DBDs can be formed on both sides of the substrate and a large quantity of exhaust gas components can be treated in a given volume.

[0065] According to various design variants, several of the aforementioned dielectrically insulated substrates can be arranged parallel to each other in the reactor.

[0066] This allows for the space-saving generation of S-DBDs within the reactor chamber, enabling the treatment of exhaust gas components in a small area. The space requirement of the exhaust gas treatment system is therefore minimal.

[0067] According to various design variants, several of the aforementioned dielectrically insulated substrates can be arranged in series in the reactor, preferably in series with respect to the flow direction of the exhaust gas.

[0068] This allows for adequate treatment of exhaust gas components even at high flow velocities, as a sufficiently long contact time with the S-DBDs is possible. Multiple substrates in series also offer the possibility of forming different S-DBDs or adapting the S-DBDs to the exhaust gas components being treated. For example, a first substrate can be optimized for treating a first exhaust gas component, while a second substrate, arranged in series behind the first, is optimized for treating a second exhaust gas component.

[0069] According to further embodiments, the exhaust gas treatment system can have a catalyst material arranged in spaces of the electrically conductive structure, e.g. a gold- and / or platinum-containing material or a material consisting of gold or platinum, or a catalyst based on CuO, ZnO and / or AhOs.

[0070] This enables a catalytic conversion of the exhaust gas components, which can further improve energy efficiency. Furthermore, catalysis can preferentially form certain reaction products.

[0071] By arranging the catalyst material in the spaces between the electrically conductive structures, the catalytic reaction can occur simultaneously with the S-DBD treatment. For the associated advantages, please refer to the explanations of the corresponding process above.

[0072] According to further design variants, the exhaust gas treatment system can have an absorber designed to absorb reaction products of the exhaust gas components treated by means of S-DBD.

[0073] The absorber can be designed, for example, as a scrubber with a liquid absorbent, such as water, or as a dry bed absorber. A scrubber is preferable when large quantities of reaction products are generated. Through absorption of the reaction products in the scrubber's absorbent, the products can be transformed, for example, into absorbable products that can be safely disposed of or reused.

[0074] A dry bed absorber is preferable when small quantities of reaction products are generated. In a dry bed absorber, the reaction products are continuously absorbed by a dry absorbent until the absorption capacity is exhausted and are then disposed of or further processed together with the absorbent.

[0075] Another aspect of the invention relates to a process plant with a process chamber and an exhaust gas treatment system as described above. In this respect, the above explanations of the exhaust gas treatment system also serve to describe the exhaust gas treatment system. The advantages of the exhaust gas treatment system are thus inherent in the process plant.

[0076] The process chamber of the process plant can be specifically designed for carrying out a CVD or plasma process, for example, in semiconductor manufacturing. The exhaust gas treatment system of the process plant allows for particularly efficient treatment of components of the exhaust gases generated during these processes. Naturally, multiple process chambers can also be present, enabling the exhaust gases from several chambers to be combined and treated.

[0077] The process plant may also include one or more vacuum pumps designed to remove exhaust gas from one or more process chambers.

[0078] Optionally, several vacuum pumps arranged in series and / or parallel with respect to the exhaust gas flow direction can be provided to remove the exhaust gases from one or more process chambers. The exhaust gases from several vacuum pumps can optionally be combined before being fed into the reactor.

[0079] The vacuum pump(s) allow for a uniform exhaust gas flow with an adjustable volume flow rate. This enables adaptation to the generated S-DBDs, thus facilitating efficient conversion of the exhaust gas components.

[0080] Another aspect of the invention relates to a method for manufacturing an exhaust gas treatment system according to the above description.

[0081] Therefore, the above explanations of the exhaust gas treatment system also serve to describe it. The advantages of the exhaust gas treatment system are correspondingly linked to the process plant.

[0082] The process involves forming an electrically conductive structure on a dielectrically insulated substrate and arranging the dielectrically insulated substrate in a reactor chamber of a reactor.

[0083] The electrically conductive structure can preferably be printed onto the substrate, for example, using screen printing. This has the advantage that the electrically conductive structure can be applied to the substrate quickly and cost-effectively, thus enabling high-volume production. Furthermore, printing allows for precise adjustment of the layer thickness of the electrically conductive structure. In addition, the shape of the structure, e.g., squares or a honeycomb pattern, can be easily varied by changing the print template.

[0084] Preferably, a catalyst material can be arranged in the spaces between the electrically conductive structure.

[0085] In summary, the invention, in its various embodiments, is characterized by the formation of a plasma over a dielectrically insulated plate, which is provided with a conductor structure on both sides. Due to the dielectric insulating plate between the conductor structures, the plasma can only form on the surface of the plate. The dielectric alters the shape of the electric field lines, leading to a locally enhanced electric field and a reduction in the breakdown voltage, thereby promoting discharges near the surface. Plasma vortices can form, drawing the exhaust gas to the substrate and pulling it through the high-energy zone.

[0086] The exhaust gas is passed by plates positioned parallel to each other in the reactor. The strong electric field accelerates the electrons, generating positive ions and fast electrons. When these fast electrons collide with molecules in the exhaust gas, ionization, excitation, and dissociation occur, producing further fast electrons and ions that maintain the plasma. The electric field is established and energy is fed into the system by individual, short voltage pulses, for example, pulses lasting from nanoseconds to a few microseconds. To further reduce and / or oxidize the resulting radicals, hydrogen (e.g., to form hydrogen atoms in the plasma), water vapor (e.g., to form OH radicals), and / or oxygen (e.g., to form oxygen atoms) can be added to the exhaust gas.Radicals have in common that they are much more reactive than the original parent molecules from which the radicals were formed, and can be efficiently generated in S-DBD plasma with low energy expenditure.

[0087] Optionally, the exhaust air streams from several vacuum processes can be combined and passed through a reactor, in which the exhaust gas components are converted as described and transformed into compounds that can be bound by the absorber. After passing through the reactor space or reactor chamber, the exhaust gas can be discharged into the environment via an absorber.

[0088] Further features, properties, and advantages of the present invention are explained in more detail below with reference to exemplary embodiments and the accompanying figures. It is understood that other embodiments can be used and structural or logical modifications can be made without deviating from the scope of protection of the present invention. The following description should therefore not be interpreted as restrictive. The figures show:

[0089] Fig. 1 shows a schematic representation of an exemplary dielectrically insulated substrate with electrically conductive structures;

[0090] Fig. 2 is a schematic representation of an exemplary reactor;

[0091] Fig. 3 shows a schematic representation of an exemplary process plant; and

[0092] Fig. 4 shows a flowchart of an exemplary process for treating exhaust gases.

[0093] Figure 1 shows a dielectrically insulated substrate 9 consisting essentially of Al₂O₃ in the form of a rectangular plate. The substrate 9 has a first surface 11 and a second surface opposite the first surface 11. The second surface is not visible in the representation of Figure 1, but is structured analogously to the first surface 11.

[0094] On the first surface 11, e.g., the front or top surface of the substrate 9, an electrically conductive structure 10 is formed. The electrically conductive structure 10 consists of two superimposed layers. A lower layer, i.e., the layer directly on the substrate 9, consists of MoMn and has a thickness in the range of 5 to 18 pm. Above this lower layer, an upper layer of nickel with a thickness in the range of 2 to 6 pm is deposited. The electrically conductive structure 10 is formed in the form of interconnected squares, i.e., it has a square pattern. When an alternating voltage is applied, S-DBDs form in the region of the electrically conductive structure 10, generating a cold surface-active plasma that can be used for exhaust gas treatment.Optionally, a catalyst material 13 can be arranged in the spaces 12 of the electrically conductive structure 10 to enable catalyzed exhaust gas treatment. Preferably, the catalyst material is based on A12O3.

[0095] Figure 2 shows an exemplary reactor 7 of an exhaust gas treatment system 6 for treating components of an exhaust gas 1, which has a reactor chamber 8 surrounded by housing walls 17. In the reactor chamber 8, five dielectrically insulated substrates 9 with electrically conductive structures 10 formed on them, e.g., as shown in Figure 1, are arranged parallel to one another. Of course, a different number of corresponding substrates 9 than five can also be provided.

[0096] Figure 3 shows a schematic representation of a process plant 15. The process plant 15 has a process chamber 4 in which, for example, a CVD process or an etching process can be carried out, producing exhaust gas 1. The exhaust gas 1 contains various exhaust gas components that require treatment, e.g., because they cannot be released into the environment untreated due to their toxicity.

[0097] The process plant 15 also includes an exhaust gas treatment system 6. The exhaust gas treatment system 6 comprises a reactor 7, which can be configured, for example, as shown in Figure 2, and in which the exhaust gas components are treated with s-DBD. Furthermore, the process plant 15 includes four vacuum pumps 5, although a different number is, of course, possible. The vacuum pumps 5 are fluidically connected to one or more process chambers 4, e.g., via pipelines, and are designed to remove exhaust gas 1 from the process chamber 4 by pumping. Exhaust gas flows from several process chambers 4, each with its own vacuum pump 5, can also be combined. For example, the number of vacuum pumps 5 can correspond to the number of process chambers 4.

[0098] The exhaust gas streams generated by the vacuum pumps 5 are combined downstream of the vacuum pumps 5 and fed via the exhaust gas feed device 18 to the exhaust gas treatment system 6, specifically to the reactor chamber 8 of the reactor 7. Optionally, a feed device for supplying water, hydrogen, and / or oxygen to the exhaust gas 1 can be provided upstream of the reactor 7 (not shown). In the reactor chamber 8, the exhaust gas components are treated by means of S-DBD, whereby reaction products 3 are formed and discharged from the reactor 7 by means of the exhaust gas discharge device 19.

[0099] The exhaust gas treatment system 6 also includes an absorber 14, which can be configured as a scrubber or a dry bed absorber. The reaction products 3 formed during the S-DBD treatment are directed into the absorber 14 via the exhaust gas discharge device 19, where they are partially or completely absorbed. The exhaust gas 1, now free of the reaction products 3, is then released into the environment as exhaust air 16 or used for other purposes.

[0100] Figure 4 shows an exemplary flow diagram of a process 100 for treating components of an exhaust gas 1. The process 100 can be carried out, for example, using the exhaust gas treatment system 1 described with reference to Figure 3.

[0101] In a first process step S1, the exhaust gas 1 from a process chamber 4 is fed to the exhaust gas treatment system 6. For example, the exhaust gas can first be removed from the process chamber 4 by means of a vacuum pump 5, creating an exhaust gas stream which is fed to the exhaust gas treatment system. As already mentioned, the exhaust gas streams from several vacuum pumps 5 can be combined.

[0102] In the second process step S2, surface-active dielectrically hindered discharges 2 are generated in the reactor chamber 8 by means of the dielectrically insulated substrate 9 and the electrically conductive structures 10 formed on it.

[0103] In the third process step S3, the exhaust gas 1 is brought into contact with the generated S-DBDs.

[0104] In the fourth process step S4, water, hydrogen and / or oxygen can optionally be added to the exhaust gas 1.

[0105] In the fifth process step S5, halogen-containing exhaust gas components are converted to particularly absorbable reaction products 3 using the S-DBD.

[0106] In the sixth process step S6, the reaction products 3 formed are absorbed in the absorber. The remaining exhaust gas 1 is released into the environment or can be used elsewhere. The term "and / or" used here, when used in a series of two or more elements, means that each of the listed elements can be used alone, or any combination of two or more of the listed elements can be used. For example, when describing a composition containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0107] Reference numerals: Exhaust gas, surface-active dielectrically hindered discharges, reaction product, process chamber, vacuum pump, exhaust gas treatment system, reactor, reactor chamber, dielectrically insulated substrate, electrically conductive structure, surface, gap, catalyst material, absorber, process plant, exhaust air, housing wall, exhaust gas supply device, exhaust gas discharge device. Method: Supplying the exhaust gas from a process chamber, generating surface-active dielectrically hindered discharges, contacting the exhaust gas with the generated S-DBDs, adding water, hydrogen and / or oxygen to the exhaust gas, converting halogenated exhaust gas components to reaction products using the S-DBDs, absorbing the reaction products.

Claims

Patent claims 1. Method (100) for treating components of an exhaust gas (1), comprising the method (100): (52) Generating surface-active dielectrically hindered discharges (2), hereinafter referred to as S-DBD, (53) Contacting the exhaust gas (1) with the generated S-DBD (2), and (S5) Conversion of halogenated exhaust gas components to reaction products (3) using the S-DBD (2).

2. Method (100) according to claim 1, wherein the halogen-containing exhaust gas components contain fluorine.

3. Method according to claim 1 or 2, wherein the halogen-containing exhaust gas components are perhalogenated compounds.

4. Method (100) according to claim 3, wherein the perhalogenated compounds are selected from a group comprising carbon hexafluoride, tetrafluoromethane, sulfur hexafluoride, nitrogen trifluoride and octafluoropropane.

5. Method (100) according to any one of the preceding claims, comprising: (54) Adding an H and / or O donor to the exhaust gas (1).

6. Method (100) according to claim 5, wherein the H and / or O donor is selected from the group comprising water, hydrogen, oxygen and ozone.

7. Method (100) according to one of the preceding claims, wherein the conversion of the halogen-containing exhaust gas components is catalyzed.

8. Exhaust gas treatment system (6) for treating components of an exhaust gas (1), the exhaust gas treatment system (6) comprising: a reactor (7) with a reactor chamber (8) and a dielectrically insulated substrate (9) arranged in the reactor chamber (8), wherein an electrically conductive structure (10) for generating surface-active dielectrically hindered discharges (2) is formed on the substrate (9).

9. Exhaust gas treatment system (6) according to claim 8, wherein said electrically conductive structures (10) are formed on opposing surfaces (11) of the dielectrically insulated substrate (9).

10. Exhaust gas treatment system (6) according to claim 8 or 9, wherein the substrate (9) is plate-shaped.

11. Exhaust gas treatment system (6) according to one of claims 8 to 10, wherein the electrically conductive structure (10) has a square pattern and / or a honeycomb pattern.

12. Exhaust gas treatment system (6) according to one of claims 8 to 11, wherein several of said dielectrically insulated substrates (9) are arranged parallel to each other in the reactor (7).

13. Exhaust gas treatment system (6) according to one of claims 8 to 12, wherein several of said dielectrically insulated substrates (9) are arranged in series in the reactor (7).

14. Exhaust gas treatment system (6) according to one of claims 8 to 13, comprising: a catalyst material (13) arranged in spaces (12) of the electrically conductive structure (10).

15. Process plant (15) comprising a process chamber (4) and an exhaust gas treatment system (6) according to one of claims 8 to 14.

16. Method for manufacturing an exhaust gas treatment system (6) according to any one of claims 8 to 14, comprising the method: Forming an electrically conductive structure (10) on a dielectrically insulated substrate (9) and Arranging the dielectrically insulated substrate (9) in a reactor chamber (8) of a reactor (7).

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