Gas excitation apparatus, vacuum arrangement, method, and use of a plasma source

Abstract

According to various embodiments, a gas excitation apparatus (100) comprises: a plasma zone (152); a gas-conducting system (110) designed to conduct a gas stream through the plasma zone (152); and an inductive plasma source (112) designed to excite the formation of plasma in the plasma zone (152).

Description

[0001] Description

[0002] Gas excitation device, vacuum arrangement, method and use of a plasma source

[0003] Various embodiments relate to a gas excitation device, a vacuum arrangement, a method and a use of a plasma source.

[0004] In general, strip substrates (e.g., metal strips, foils, or other flexible substrates) can be coated (and / or otherwise treated) in a coating system (e.g., in a continuous coating system or in a batch coating system). For example, a strip substrate can be transported through a coating area of ​​a coating chamber by means of a transport system. The transport system can, for example, be configured such that the strip substrate is processed from roll to roll, wherein the strip substrate is unwound from a first substrate winding roll, transported through the coating area, and, after coating, is rewound onto a second substrate winding roll. The coating chamber can be configured as a vacuum chamber so that the strip substrate can be coated in a vacuum. For example, the strip substrate can be coated by means of vapor deposition, e.g.,Chemical vapor deposition (CVD) or physical vapor deposition (PVD) can be applied. The strip substrate can be moved into and / or out of the vacuum chamber, for example, in a so-called air-to-air configuration using multiple locks (e.g., strip locks or roller locks). Alternatively, the two rollers for winding and unwinding the strip substrate can be moved into the vacuum chamber, so that the vacuum chamber must be ventilated cyclically to exchange the strip substrate.

[0005] In some applications, it is necessary to coat the substrate with a chemical compound that is difficult to convert to the gaseous state. In such cases, often only one component (e.g., the metal) of the chemical compound is converted to the gaseous state and then exposed (e.g., in the gaseous state or as a deposited layer) to a so-called reactive gas, with which it reacts to form the chemical compound. This chemical reaction can be promoted by activating the reactive gas.

[0006] Examples of activation are based on the coupling of microwaves into the mixture of reactive gas and metal using a horn antenna. For example, microwaves are coupled into an aluminum vapor-oxygen mixture via horn antennas serving as microwave guides near the crucible through quartz glass windows. The provision and conduction of the microwaves in a vacuum, as well as the transmission of the microwaves to the processing site, is complex and requires a great deal of installation space. The quartz glass windows, in particular, represent a weak point because they become impermeable to microwaves due to an electrically conductive coating. They then reflect the microwave power, which then has to be dissipated elsewhere. A shutter installed for this purpose and additional gas purges in front of the quartz glass window inhibit this process, but they make the system more complex and require additional installation space.Despite the measures mentioned, the system is susceptible to failures of individual modules, which promotes inhomogeneity of the layer properties.

[0007] Other examples of activation are based on a hollow cathode arc discharge. Hollow cathodes generate a very intense plasma, with various excitation processes taking place in the vapor or gas in front of the hollow cathode due to escaping electrons. However, the effect of the plasma is very strongly localized at the hollow cathode as the plasma source. Additional auxiliary anodes and / or magnetic fields can expand the plasma but not homogenize it. The inhomogeneity from source to source thus remains, so that very small distances between the sources are traditionally chosen, for example, from 0.2 m (meters) to 0.5 m, in order to achieve the most homogeneous effect possible during layer deposition.Installation is therefore associated with considerable expenditure, as each hollow cathode must be operated with currents of several hundred amperes, which often requires water-cooled copper power supplies with cross-sections of several square centimeters. This situation is further complicated by the fact that each hollow cathode requires an individual power supply. The large number of hollow cathodes combined with the technical challenges significantly increases the complexity and probability of failure of the overall system. In addition to the technical hurdles, the high currents supplying the hollow cathodes create magnetic fields, which, in the event of vapor generation by electron beams, lead to the deflection of the electron beam. This can only be prevented by spatially and magnetically decoupling the electron beam supply from the plasma generation by the hollow cathode using a magnetic trap.The latter significantly limits the technical possibilities of hollow cathode arc discharge, for example for use in strip coating.

[0008] According to various embodiments, it has been recognized that, particularly for a homogeneous coating of the widest possible strip substrate, no technically attractive device for providing activated process gas is available. This applies analogously to other types of PVD processes, in which it can be advantageous to be able to introduce activated process gas. For example, various properties of the layer formed on the substrate can be influenced, e.g., controlled and / or regulated, using the activated process gas. Examples of these properties of the layer formed on the substrate include: the chemical composition of the layer, the structural and / or crystalline growth of the layer, and the application-specific layer properties (e.g., transparency, conductivity, etc.).

[0009] According to various embodiments, a gas excitation device, a vacuum arrangement, a method, and a use of a plasma source are provided that address these aspects, in particular the need for a technically robust and efficient gas excitation device as an excitation source for a process gas (also referred to as a source of activated process gas), e.g., reactive gas, which requires a small installation space (e.g., near the coating zone), has a long service life, and can be adjusted with few operating actions. Various examples are described below that relate to what is described herein and illustrated in the figures.

[0010] Example 1 is a gas excitation device (e.g., for use as a source of activated process gas), comprising: a plasma region; a gas guidance system configured to guide a gas flow through the plasma region; an inductive plasma source configured to excite plasma formation in the plasma region (e.g., when the gas flow is guided through the plasma region); and preferably comprising a compensation element.

[0011] Example 2 is the gas excitation device according to Example 1, wherein the inductive plasma source is configured to couple an (e.g. time-varying) electromagnetic field (e.g. magnetic field and / or alternating field) into the plasma region, preferably the gas stream passed through it, in order to stimulate the plasma formation in the plasma region.

[0012] Example 3 is the gas excitation device according to example 1 or 2, wherein the gas guide system comprises: a gas supply which opens into the plasma region, for supplying the gas flow into the plasma region; wherein the gas supply preferably has a plurality of (e.g., coupled to one another) supply openings, each supply opening of which opens into the plasma region; wherein further preferably the gas supply has a gas connection which couples the plurality of supply openings to one another in a gas-conducting manner and / or is configured to be coupled to a gas supply (e.g., having a gas line and / or a gas reservoir).

[0013] Example 4 is the gas excitation device according to any one of Examples 1 to 3, wherein the gas guidance system comprises: a gas discharge, which opens into the plasma region, for discharging the gas flow out of the plasma region; wherein the gas discharge preferably comprises a plurality of gas outlet openings (e.g., provided by nozzles and / or coupled to one another), which are further preferably arranged in a row one behind the other and / or open into an environment of the gas excitation device.

[0014] Example 5 is the gas excitation device according to any one of examples 1 to 4, further comprising: a (e.g. electrically conductive) housing in which the plasma region (e.g. delimited on six sides by means of the housing) and / or the inductive plasma source is arranged and / or through which the gas flow is guided by means of the gas guide system; wherein the gas guide system is preferably at least partially integrated in the housing, e.g. having one or more than one opening (e.g. gas outlet opening and / or feed opening) which penetrates a wall of the housing (also referred to as the housing wall); and / or wherein the interior of the housing provides the plasma region.

[0015] Example 6 is the gas excitation device according to any one of examples 1 to 5, further comprising: an electrical connection coupled to the at least one inductive plasma source for supplying the at least one inductive plasma source with electrical power, e.g. by means of an electrical line coupled to the electrical connection, wherein the electrical line preferably has a supply line and a return line optionally surrounding the supply line.

[0016] Example 7 is the gas excitation device according to any one of examples 1 to 6, further comprising: the compensation element (also referred to as plasma homogenization element), which is preferably configured to compensate for a first spatial variation of the plasma formation, which is excited by means of a first section (e.g. having a plurality of coil turns) of the plasma source.

[0017] Example 8 is the gas excitation device according to Example 7, wherein the compensation element is configured to provide (e.g. along the coil axis) a second spatial variation (which is, for example, superimposed on the first variation) of one or more of the following: the plasma formation, which is excited by means of a second section (e.g. having several coil turns) of the plasma source; the gas flow, which is preferably excited by means of mixing of the gas flow and / or a pressure difference of the gas flow; a gas conductivity of the gas guide system; a path (e.g. its length) of the gas guide system along which the gas flow is guided away from the plasma region. For example, it can be exploited that the excitation of the gas flow decreases over time, which makes it possible to adapt the degree of excitation of the gas flow over the path length that the gas flow travels before reaching the coating material.

[0018] Example 9 is the gas excitation device according to any one of Examples 1 to 8, wherein the inductive plasma source (e.g., along the coil axis) exhibits a spatial variation (e.g., decrease or increase, e.g., along a path) in a contribution to its inductance; and / or wherein at least two sections (e.g., matching in the number of coil turns) of the plasma source differ from each other in their inductance.

[0019] Example 10 is the gas excitation device according to any one of Examples 1 to 9, wherein the inductive plasma source (e.g., each section thereof) comprises one or more than one electromagnetic coil (e.g., comprising multiple coil turns), which is preferably arranged in the plasma region; and / or wherein each section (e.g., comprising multiple coil turns) of the plasma source is adjacent to an electrical terminal by means of which the plasma source is supplied with electrical power, and to a potential equalization device.

[0020] Example 11 is the gas excitation device of Example 10, wherein the inductive plasma source has a spatial variation (e.g., along the coil axis) (e.g., decrease or increase, e.g., along a path, e.g., along the coil axis) of one or more than one of: a spatial density of immediately adjacent coil turns (also referred to as windings of a coil); a diameter of immediately adjacent coil turns; and / or an inductance of immediately adjacent coil turns.

[0021] Example 12 is the gas excitation device according to example 10 or 11, wherein the plasma source comprises a plurality of sections which differ from one another in one or more than one of the following: a winding sense, e.g., of their coils (which, e.g., reduces the impact effect of the magnetic field); a direction of variation in inductance; a position of a potential equalization device (e.g., grounding device) at which they adjoin one another, which preferably provides a reference potential (e.g., electrical ground), wherein preferably the potential equalization device is provided by means of the housing.

[0022] Example 13 is a vacuum arrangement comprising: a coating device configured to coat a substrate (e.g., a strip substrate) in a vacuum using a coating material to which the substrate is exposed; and the gas excitation device according to any one of Examples 1 to 12 configured to expose the coating material to the gas stream exiting the plasma region (or at least exiting the gas excitation device).

[0023] Example 14 is the vacuum arrangement according to Example 13, further comprising: a transport device (e.g. comprising a plurality of transport rollers) for transporting the substrate past the coating device and / or the gas excitation device, wherein the transport device is configured, for example, to transport a strip substrate.

[0024] Example 15 is the vacuum arrangement according to example 13 or 14, further comprising: a vacuum chamber in which the coating takes place, wherein preferably the coating device and / or the gas excitation device are arranged in the vacuum chamber.

[0025] Example 16 is a method (e.g., for operating any of Examples 1 to 15), comprising: passing a gas stream through a plasma region into a vacuum; inducing plasma formation in the plasma region through which the gas stream is passed by means of at least one inductive plasma source and / or by means of an alternating magnetic field; preferably coating a substrate by means of a coating material that is exposed to (and / or chemically reacts with) the gas stream emerging from the plasma region.

[0026] Example 17 is using an inductive plasma source to stimulate plasma formation in the plasma region through which a gas stream is passed, preferably exposed to (and / or chemically reacted with) a coating material by means of which a substrate is coated and / or the substrate is exposed.

[0027] Example 18 is configured according to any one of Examples 1 to 17, wherein the plasma region is a cavity.

[0028] Example 19 is configured according to any one of Examples 1 to 18, wherein the transport device is configured to transport the substrate at a speed of, for example, in a range of approximately 2 meters per second (m / s) to approximately 20 m / s (preferably 10 m / s), e.g., of, for example, in a range of approximately 5 m / s (preferably 10 m / s, more preferably 15 m / s) to approximately 20 m / s; and / or wherein the substrate is transported at the speed. Example 20 is configured according to any one of Examples 1 to 19, wherein the substrate is strip-shaped (also referred to as a strip substrate).

[0029] Example 21 is configured according to any one of Examples 1 to 20, wherein the coating device comprises an electron beam gun and / or a crucible; and / or wherein the coating is performed by means of thermal evaporation (e.g., of the coating material).

[0030] Example 22 is configured according to any one of Examples 1 to 21, wherein the coating material chemically reacts with the gas stream.

[0031] Example 23 is configured according to any one of Examples 1 to 22, wherein the gas stream emitted by the gas excitation device is at least partially in an excited state comprising, for example, free charge carriers (e.g., comprising electrons and / or ions) and / or radicals.

[0032] Example 24 is configured according to any one of examples 1 to 23, wherein the excitation of the plasma formation takes place by means of an alternating field (e.g. electromagnetic alternating field, e.g. magnetic alternating field) which is provided by means of the plasma source, and / or by means of an inductive plasma source (e.g. a coil).

[0033] Example 25 is configured according to any one of Examples 1 to 24, wherein the inductive plasma source comprises one or more than one electromagnetic coil, the interior of which (also referred to as coil interior) provides the plasma region (at least in sections).

[0034] Example 26 is configured according to any one of Examples 1 to 25, wherein the electromagnetic energy used (e.g. required) to excite the plasma is fed into the junction of two coil sections with opposite winding senses, while the ends of the coil sections are at return conductor and / or ground potential.

[0035] Example 27 is configured according to any one of Examples 1 to 26, wherein the electromagnetic energy used (e.g. required) to excite the plasma is fed into the connecting point of two coil sections with the same winding direction, while the ends of the coil sections are at return conductor and / or ground potential.

[0036] Example 28 is configured according to any one of examples 1 to 27, wherein the or each electromagnetic coil is cylindrical, eg tubular (eg configured as a tubular coil), wherein the or each electromagnetic coil is eg a cylindrical coil.

[0037] Example 29 is configured according to any one of Examples 1 to 28, wherein the or each electromagnetic coil has exactly one coil turn. Example 30 is configured according to any one of Examples 1 to 29, wherein the or each electromagnetic coil has exactly one or more coil turns.

[0038] Example 31 is configured according to any one of Examples 1 to 30, wherein the coil axis is arranged in the gas flow.

[0039] Example 32 is configured according to any one of Examples 1 to 31, wherein the gas guidance system is configured to guide a gas flow through the plasma region along a direction that is transverse to a coil axis of the plasma source (e.g., one or more than one coil thereof) and / or along which the gas outlet openings open into the plasma region.

[0040] Example 33 is configured according to any one of Examples 1 to 32, wherein the or each coil is penetrated along the coil axis by a through-opening in which at least a portion (also referred to as coil interior) of the plasma region is arranged.

[0041] Example 34 is configured according to any one of Examples 1 to 33, wherein the gas guidance system is configured to guide a gas flow through the plasma region along a direction along which the plasma source (e.g., one or more coils thereof) is penetrated by one or more gas guidance openings. The or each gas guidance opening may, for example, be formed by a gap formed between two coil turns.

[0042] Example 35 is configured according to any one of Examples 1 to 34, wherein the or each coil has a (eg, linear or curved) coil axis and (eg, exactly) a wall-shaped electrical line curved around the coil axis and providing exactly one coil turn.

[0043] Example 36 is configured according to any one of examples 1 to 35, wherein the plasma source comprises two electromagnetic coils arranged one behind the other along a coil axis, which differ from one another in their winding sense.

[0044] Example 37 is configured according to any one of Examples 1 to 36, wherein the plasma source comprises two first electromagnetic coils arranged one behind the other along a first coil axis, which optionally coincide in their winding sense, and wherein the plasma source comprises two second electromagnetic coils arranged one behind the other along a second coil axis, which optionally coincide in their winding sense. Preferably, the two first coils differ from the two second coils in their winding sense.

[0045] Example 38 is configured according to example 37, wherein the first coil axis and the second coil axis are arranged next to each other, e.g. parallel to each other.

[0046] Example 39 is configured according to any one of Examples 1 to 38, wherein the or each coil comprises or consists of aluminum. Example 40 is configured according to any one of Examples 1 to 39, wherein the or each coil is coated with a ceramic (e.g., oxide) that preferably comprises aluminum and / or magnesium.

[0047] Example 41 is configured according to any one of Examples 1 to 40, wherein the plasma source comprises one or more than one coil provided (e.g., a coil turn thereof) by means of a fluid conduit, preferably comprising a cavity for receiving a cooling fluid.

[0048] Example 42 is configured according to any one of Examples 1 to 41, wherein (e.g., more than 50%, e.g., 75%, e.g., 95% thereof) of the gas outlet openings (e.g., each of them) are arranged adjacent to a contour of the coil windings of the plasma source projected onto the wall of the housing (e.g., along the gas outlet direction, e.g., the flow direction), or at least only adjacent to those portions of the contour that are the closest distance from the coil windings. This inhibits disruptive plasma formation through the gas outlet openings.

[0049] Example 43 is configured according to any one of Examples 1 to 42, wherein each coil winding of the plasma source has a first distance from the housing wall through which the gas outlet openings pass (e.g., along the gas outlet direction), and a second distance from one of the gas outlet openings immediately adjacent to the coil winding, which second distance is greater than the first distance (e.g., 110% thereof, e.g., 120% thereof, e.g., 130% thereof, e.g., 150% thereof). This inhibits disruptive plasma formation through the gas outlet openings.

[0050] Example 44 is configured according to any one of Examples 1 to 43, wherein the gas outlet openings are arranged equidistant from one another.

[0051] Example 45 is configured according to any one of Examples 1 to 44, wherein the gas outlet openings are covered by a (gas-permeable and / or electrically conductive) protective wall, wherein the housing wall is arranged between the protective wall and the plasma source. For example, the protective wall may comprise a metallic grid or perforated sheet. For example, the protective wall may be penetrated by several openings per gas outlet opening of the gas outlet openings. For example, the protective wall may comprise several filaments between which the openings are formed.

[0052] Example 46 is configured according to any one of Examples 1 to 45, wherein each coil has at least one winding about a coil axis that is transverse to a direction of gas flow (also referred to as a flow direction).

[0053] Example 47 is configured according to any one of Examples 1 to 46, wherein the housing is electrically conductive (e.g., metallic). Example 48 is configured according to any one of Examples 1 to 47, further comprising: a voltage supply configured to apply a (e.g., pulsed) direct voltage to the housing. This promotes the transport of ions out of the housing. The direct voltage can be applied, for example, between the housing and the coating device and / or between the housing and a substrate holder configured to hold the substrate. The substrate holder can, for example, be configured as a transport system.

[0054] Example 49 is configured according to any one of Examples 1 to 48, wherein the one or more than one coil comprises at least one winding about a coil axis that is transverse to a direction of gas flow along which the gas flow is guided through the plasma region or out of the plasma region (e.g., by means of the gas exhaust).

[0055] Example 50 is configured according to any one of examples 1 to 49, wherein the alternating electromagnetic field is generated by means of one or more than one coil through which the gas flow is passed.

[0056] Example 51 is configured according to any one of Examples 1 to 50, wherein the plasma source is exposed to plasma formation or at least to the gas flow.

[0057] Example 52 is configured according to any one of Examples 1 to 51, wherein the more than one coil comprises two coils coupled to each other by means of an electrical terminal as a feed point arranged between the two coils.

[0058] Example 53 is configured according to any one of Examples 1 to 52, further comprising, e.g., per coil, a tube made of a dielectric arranged within the coil, wherein the tube is preferably penetrated by a plurality of gas passage openings. For example, the plurality of gas passage openings, e.g., per gas outlet opening, may comprise one or more than one gas passage opening directed towards the gas outlet opening. For example, each of the plurality of gas passage openings may be directed towards the coil axis and / or a wall of the housing (if present). For example, the plurality of gas passage openings, e.g., per supply openings, may comprise one or more than one gas passage opening directed towards the supply openings.

[0059] Example 54 is configured according to any one of Examples 1 to 53 and further according to any one of the appended claims.

[0060] It shows

[0061] Figure 1 shows a gas excitation device according to various embodiments in a schematic side view or cross-sectional view; Figure 2 shows the gas guidance system according to various embodiments in a schematic side view or cross-sectional view;

[0062] Figures 3A to F each show a gas excitation device according to various embodiments in a schematic diagram;

[0063] Figure 4 shows a gas excitation device according to various embodiments in a schematic semi-transparent perspective view;

[0064] Figure 5 shows a vacuum arrangement according to various embodiments in a schematic side view or cross-sectional view;

[0065] Figure 6 shows a method according to various embodiments in a schematic flow diagram; and

[0066] Figures 7 and 8 each show a gas excitation device according to different embodiments in different schematic views.

[0067] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top," "bottom," "front," "back," "fore," "rear," etc., will be used with reference to the orientation of the described figure(s). Since components of embodiments can be positioned in a number of different orientations, the directional terminology is for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention.It is understood that the features of the various exemplary embodiments described herein may be combined with one another unless specifically stated otherwise. The following detailed description is therefore not to be construed in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0068] Throughout this description, the terms "connected," "attached," and "coupled" are used to describe both a direct and an indirect connection (e.g., resistive and / or electrically conductive, e.g., an electrically conductive connection), a direct or indirect connection, and a direct or indirect coupling. In the figures, identical or similar elements are provided with identical reference numerals where appropriate.

[0069] According to various embodiments, the term "coupled" or "coupling" can be understood in the sense of a (e.g., mechanical, hydrostatic, thermal, and / or electrical), e.g., direct or indirect, connection and / or interaction. For example, several elements can be coupled to one another along an interaction chain, along which the interaction can be exchanged, e.g., a fluid (then also referred to as fluid-conductingly coupled). For example, two coupled elements can exchange an interaction with one another, e.g., a mechanical, hydrostatic, thermal, and / or electrical interaction. According to various embodiments, "coupled" can be understood in the sense of a mechanical (e.g., physical) coupling, e.g., by means of direct physical contact. A coupling can be configured to transmit a mechanical interaction (e.g., force, torque, etc.).

[0070] The term "inductive" in relation to a device can be understood as having an inductance, for example of more than approximately 200 nanohenries (nH), e.g. more than approximately 500 nH, e.g. more than approximately 1000 nH, e.g. more than approximately 2000 nH. The term "inductive" in relation to a process (e.g. excitation) can be understood as taking place by means of (e.g. mainly) a magnetic field, for example of more than approximately 60 microtesla (pT), e.g. as approximately 100 pT, e.g. as approximately 150 pT, e.g. as approximately 250 pT. For example, inductive excitation of plasma formation can have the ionization rate of the plasma formation brought about by means of the magnetic field being greater than the ionization rate of the plasma formation brought about by means of an electric field (if present).

[0071] A spatial variation in plasma formation can be understood as one or more properties of the plasma formation (e.g., its ionization rate, power consumption) and / or of the resulting plasma (e.g., its temperature, degree of ionization, and / or pressure) being a location-dependent function, e.g., dependent on a location on the coil axis. For example, this function may exhibit a gradient, e.g., in one direction (e.g., along the coil axis and / or toward the electrical connection). The direction of the gradient indicates the direction in which the function value increases.

[0072] The term “plasma source” can be understood as a device that is designed to generate a plasma. The term “plasma” refers to a fluid (e.g. a mixture of particles) that contains ions, free electrons and / or radicals and optionally neutrally charged particles (e.g. atoms or molecules). The plasma therefore contains free charge carriers (e.g. ions and / or electrons). The degree of ionization is understood to be the ratio of charge carriers to electrically neutral portions of the plasma. The plasma can be formed (also referred to as plasma formation) using a so-called process gas (also referred to as plasma-forming gas), for example by ionizing the process gas and / or such that the degree of ionization of the plasma is increased or at least maintained. The plasma can, for example, have a degree of ionization of more than approximately 0.5%, than approximately 1%, e.g. than approximately 2%, e.g. than approximately 3%.The rate at which the degree of ionization of a quantity of the process gas is changed can be expressed as the ionization rate, which describes the rate at which neutral particles of the process gas are converted into free charge carriers (also called ionization).

[0073] Plasma formation can be stimulated, for example, by means of a magnetic field (also referred to as inductive plasma excitation and inductive excitation for short). In an exemplary implementation, a (e.g., high-frequency) alternating current (also referred to as excitation current) through an electromagnetic coil (simply also referred to as coil or excitation coil) generates a magnetic field (also referred to as magnetic excitation field or simply as excitation field), to which the process gas and / or the plasma is exposed, so that a current flow is induced therein, which ionizes it (also referred to as plasma formation). The excitation field and / or the excitation current can, for example, have a frequency (also referred to as excitation frequency) in a range from approximately 10 megahertz (MHz) to approximately 100 MHz, e.g., 13.56 MHz or more, e.g.,

[0074] 27.12 MHz or more, e.g., 40.68 MHz or more. Herein, the term "magnetic field" refers to the magnetic component (also referred to as the magnetic field) of an electromagnetic field, and the term "electric field" refers to the electric component of the electromagnetic field. If the electromagnetic field (e.g., the magnetic field) varies over time, e.g., according to the excitation frequency, it is referred to as an alternating field.

[0075] Depending on the intended use, the process gas can comprise or consist of a working gas (e.g. inert gas) and / or a reactive gas. The working gas refers to a gaseous material which is inert (e.g. towards the coating material), in other words which participates in few or no chemical reactions (e.g. with the coating material). The working gas can, for example, comprise a noble gas (e.g. helium, neon, argon, krypton, xenon) or several noble gases. The reactive gas can have a higher chemical reactivity than the working gas, e.g. with regard to the coating material. The reactive gas can, for example, comprise or consist of (e.g. molecular) oxygen, (e.g. molecular) nitrogen and / or (e.g. molecular) hydrogen. For example, the process gas can comprise only one type of gas or a gas mixture which reacts with the coating material to form a solid or is inert towards it.The process gas can be guided (e.g. supplied and / or discharged) by means of a gas guidance system.

[0076] The term "gas guidance system" can be understood as a system of gas-conducting components (such as gas lines, cavities, valves or other actuators, etc.) which provides one or more paths (also referred to as flow paths) along which the propagation of a gas (e.g. the process gas) is guided, so that the gas spreads, e.g. flows, along the flow path. The resulting (e.g. directed) propagation of the gas (along the flow path) is also referred to as gas stream or gas flow. For example, the gas flows along the guide path through one or more regions and / or into one region.

[0077] An inductive plasma source can be understood as a device configured to generate the magnetic excitation field (e.g., alternating field) in such a way that plasma formation is stimulated in a plasma region exposed to the excitation field (e.g., penetrated by it). Plasma formation can involve ionizing a gas (e.g., process gas) arranged in the plasma region (and thus exposed to the excitation field). An exemplary implementation of the inductive plasma source comprises one or more electromagnetic coils, as will be described in more detail later.

[0078] An electromagnetic coil is a device that has a (e.g., linear or curved) coil axis and an electrical conductor (e.g., a cable) wound around the coil axis (also referred to as a coil winding, or simply as turns or windings). The winding sense, relative to a reference (e.g., spatial direction and / or pole direction), indicates the direction of the path along which the conductor is wound around the coil axis. If two coils differ in their winding sense, they generate opposing magnetic field directions at the coil axis if the pole direction is identical.

[0079] Optionally, the coil line can be a (e.g., tubular) hollow line. The hollow line allows for the inclusion of a cooling fluid, which can be used to cool the plasma source. For example, the cooling fluid can flow through the hollow line. If the hollow line is further coupled to a potential equalization device (e.g., grounded thereby), this simplifies the design, as a potential reduction path for the cooling fluid can be eliminated.

[0080] For example, the or each excitation coil may have a number of turns of more than 3, e.g., 5, e.g., 10, e.g., 20, e.g., 30. Alternatively or additionally, the or each excitation coil may have an inductance of more than about 150 (e.g., 200) nanohenry (nH), e.g., more than about 500 nH, e.g., more than about 1000 nH, e.g., more than about 2000 nH, and / or less than 5 millihenry.

[0081] The term "parallel" in the context of the electrical connection of two electrical objects (e.g. two components or two groups of components) can be understood as the existence of a closed current path which runs through each of the two objects.

[0082] The term "antiparallel" in the context of two electrical components (or, by analogy, groups of components) can be understood to mean that they are connected antiparallel to one another and / or are spatially aligned antiparallel to one another, for example with regard to the two poles of each of the components. For a component whose operation depends on its orientation (and thus the orientation of the poles), for example relative to the current flow along the current path through them, this orientation is usually specified as the orientation of the poles. In an "antiparallel" connection, the poles of the two components are aligned opposite to one another relative to the current path. In an "antiparallel" alignment, the two components are aligned opposite to one another relative to the same spatial direction.The orientation of the poles can, for example, be related to a direction along which a property of the component varies.

[0083] According to various embodiments, an electron beam can be understood as a directed (e.g. collinear and / or collimated) propagation of electrons. The power density introduced by means of the electron beam (power per area of ​​the electron beam) can fluctuate and / or decrease only insignificantly. If the electron beam is deflected, its power (i.e. the radiation flux) is clearly distributed in the swept space in a time-dependent manner, i.e. a spatially distributed power density is provided. The spatially distributed power density can generally be related to the deflection angle α and expressed by the direction-dependent radiation intensity (radiation flux per solid angle). According to various embodiments, the vacuum chamber can be or can be provided by means of a chamber housing in which one or more chambers can be or can be provided.The chamber housing can, for example, be coupled (e.g., gas-conducting) to a pump arrangement, e.g., a vacuum pump arrangement, for providing a negative pressure or a vacuum (vacuum chamber housing), and can be configured so stably that it can withstand the effects of air pressure in the pumped-out state. The pump arrangement (comprising at least one vacuum pump, e.g., a high-vacuum pump, e.g., a turbomolecular pump) can make it possible to pump out part of the gas from the interior of the processing chamber, e.g., from the processing space. Accordingly, one or more vacuum chambers can be provided in one chamber housing. In other words, the chamber housing can be configured as a vacuum chamber housing, or a coating chamber can be configured as a vacuum chamber.

[0084] According to various embodiments, a chamber housing, e.g. a vacuum chamber provided therein, may be configured such that a negative pressure (i.e. a pressure less than atmospheric pressure) may be provided therein, e.g. a vacuum (i.e. a pressure of less than 0.3 bar), e.g. a pressure in a range of approximately 10 mbar to approximately 1 mbar (in other words rough vacuum) or less, e.g. a pressure in a range of approximately 1 mbar to approximately 10' 3 mbar (in other words fine vacuum) or less, e.g. a pressure in a range of approximately 10 3 mbar to approximately 10 7 mbar (in other words high vacuum) or less, e.g. a pressure less than high vacuum, e.g. less than about 10 7 mbar. Atmospheric pressure (e.g., 1 bar) can be the pressure acting on the chamber housing from the outside.

[0085] A crucible can generally comprise a crucible pan which has a hollow space (the so-called crucible interior) in which the (e.g. solid and / or liquid) vaporization material, e.g. the coating material, can be accommodated. The upper opening of the crucible pan, which exposes the crucible interior, can also be referred to as the vapor outlet opening. The vaporization material vaporized in the crucible interior can flow out of the vapor outlet opening as vapor. Optionally, the crucible can have a shield surrounding the crucible pan, which inhibits the radiation of thermal energy from the crucible pan. Optionally, the crucible can have a lid (also referred to as crucible lid) which closes the vapor outlet opening, e.g. airtight (i.e. hermetically).

[0086] Fig. 1 illustrates a gas excitation device 100 (e.g., according to Example 1) according to various embodiments in a schematic side view or cross-sectional view, comprising the plasma region 152, the gas guidance system 110, and the inductive plasma source 112. Furthermore, an exemplary course of the flow path 110p is shown, along which the process gas is guided through the plasma region 152 (also referred to as gas flow). An exemplary implementation of the inductive plasma source according to Example 2 comprises one or more electromagnetic coils configured to generate the excitation field and to couple it into the plasma region, preferably the gas flow of the process gas guided through it. The electrical current thereby excited in the process gas can stimulate plasma formation.

[0087] An exemplary implementation of the gas excitation device 100 according to Example 6 further comprises an electrical terminal (not shown) coupled to one or more than one excitation coil 302a of the plasma source 112, e.g., coupling two excitation coils of the plasma source 110 together.

[0088] Fig.2 illustrates the gas guidance system 110 according to various embodiments 200 (e.g. according to Example 3) in a schematic side view or cross-sectional view.

[0089] An exemplary implementation of the gas supply 202 has one or more than one supply opening 202o, which opens into the plasma region 152. The supply openings 202o promote a homogeneous distribution of the process gas (then also referred to as a gas distributor) in the plasma region 152, for example, the more homogeneous the distribution, the more supply openings 202o are present. For example, one or more than one supply opening 202o of the gas supply 202 can be configured to generate a laminar gas flow of the process gas into the plasma region 152. Alternatively or additionally, one or more than one supply opening 202o of the gas supply 202 can be configured to generate a turbulent gas flow of the process gas into the plasma region 152, which promotes mixing of the plasma.

[0090] An exemplary implementation of the gas supply system 110 has a gas connection 202a to which a gas supply can be connected. The process gas can be supplied to the gas supply 202 via the gas supply, so that it exits as a gas stream from one or more supply openings 202o.

[0091] An exemplary implementation of the gas guidance system 110 according to Example 4 comprises a wall (e.g., a plate) as the gas discharge 204, which is penetrated by a plurality of through-openings 204o (also referred to as gas outlet openings) (also referred to as a perforated wall). Alternatively or additionally, each of the gas outlet openings 204o can be provided by means of a nozzle.

[0092] If the gas outlet openings 204o and the supply openings 202o are arranged on opposite sides of the plasma region 152, a directed gas flow of the process gas through the plasma region 152 can be promoted. However, it can be understood that these can also be arranged differently, for example, if at least some of the gas outlet openings 204o are arranged laterally of the plasma region 152.

[0093] An exemplary implementation of the gas guidance system 110 according to Example 5 comprises a housing in which the plasma region 152 is arranged and which has two housing walls, of which a first housing wall is penetrated by the supply openings 202o and a second housing wall (e.g., opposite the first housing wall) is penetrated by the gas outlet openings 204o. Optionally, the housing can be electrically conductive, which improves electromagnetic shielding. Optionally, the housing can be coupled to or provide a potential equalization device (e.g., grounded), which improves electromagnetic shielding and, if present, facilitates cooling of the plasma source 112.

[0094] The equipotential bonding device is clearly configured to provide a reference potential and to bring the point of the plasma source coupled to the equipotential bonding device to the reference potential or at least to couple it thereto. For example, the housing can be configured as an equipotential bonding device. Alternatively or additionally, the equipotential bonding device can be configured as a grounding device that is coupled to electrical ground as a reference potential (also referred to as grounded).

[0095] Fig. 3A to Fig. 3D each illustrate a gas excitation device 100 according to various embodiments 300a to 300d (e.g., according to Example 7 and / or 8) in a schematic circuit diagram and / or schematic positioning diagram. Direction 105 can, for example, be parallel to the direction of the gas flow through the plasma region 152 (then also referred to as flow direction 105).

[0096] In general, a spatial variation of the plasma formation in the plasma region 152 (also referred to as disturbance of the plasma formation) can occur, for example due to one or more than one influence (also referred to as disturbance variable), which is, for example, superimposed on the excitation field, interacts with the process gas and / or the plasma.

[0097] Examples of such disturbances, or at least causes thereof, include: asymmetric coupling of the excitation current into an excitation coil, capacitive interaction of the excitation coil and / or components electrically coupled thereto with the gas guide system 110 (also referred to as parasitic capacitance), a structural (e.g., geometric) property of the excitation coil, etc. For example, the excitation current can interact with the excitation field via the inductance of the excitation coil and interact with the electric field via the parasitic capacitance, both of which superimpose themselves to form an electromagnetic field to which the plasma region 152 is exposed (e.g., penetrated by it). It can be understood that what has been described for the parasitic capacitance can apply analogously to one or more disturbances occurring alternatively or in addition to it (e.g., interactions that disrupt plasma formation).

[0098] According to various embodiments, the gas excitation device 100 comprises a compensation element configured to compensate for the disturbance in plasma formation (e.g., to counteract it). The compensation element is configured, for example, to interact with and / or superimpose the excitation field. Various design features for implementing the compensation element are explained below. These are based on multiple excitation coils, each of which provides a portion of the plasma source and has multiple coil turns; a first excitation coil 102a causes a first spatial variation in plasma formation, and a second excitation coil 102b causes a second spatial variation in plasma formation, which counteracts the first spatial variation.

[0099] An exemplary implementation 300a (see Fig. 3a) according to Example 8 has two excitation coils 302a, 302b, which are arranged antiparallel to each other (e.g., connected and / or aligned). Optionally, the coil axes of the two excitation coils 302a, 302b can continue one another (e.g., along one direction). Optionally, the two excitation coils 302a, 302b can differ from each other in their winding sense, so that they are aligned antiparallel to each other. For example, the two excitation coils 302a, 302b can differ in their winding sense relative to direction 105. This reduces the impact effect of the magnetic field and thus simplifies the bearing and construction.

[0100] An alternative exemplary implementation 300b (see Fig. 3a) according to Example 8 has two excitation coils 302a, 302b whose coil axes are arranged side by side. For example, the coil axes of the two excitation coils 302a, 302b can run parallel to each other. Optionally, the two excitation coils 302a, 302b can differ from each other in their winding sense, but can also be connected antiparallel, so that their impulse effect is opposite to each other.

[0101] Below, various design features of an excitation coil are explained to implement the compensation element. These features provide a spatial variation in the inductance of individual coil turns of the excitation coil (then also referred to as a variable-frequency coil) to compensate for the parasitic capacitance (e.g., its location-dependent effects). It can be understood that one or more excitation coils of implementation 300a and / or implementation 300b can be configured as such a variable-frequency coil. The parasitic capacitance can, for example, be related to the capacitive components of an interaction.

[0102] Illustratively, the coil can interact capacitively with itself and / or with the housing, e.g., as a function of the electrical voltage, which can vary along the coil axis depending on the location (e.g., between ground and the feed point). This capacitive interaction can contribute to plasma formation that is superimposed on the contribution of the inductive plasma formation. The variable coil is designed to adjust the inductance relative to the spatial variation of the capacitive interaction in such a way that the sum of both values ​​is as spatially invariant as possible.

[0103] The exemplary implementations 300c (see Fig. 3c) and 300d (see Fig. 3d) according to Examples 9 and / or 11 comprise a plurality of coil turns 312a, 312b arranged one behind the other along the coil axis (e.g., along direction 105), each coil turn providing a portion of the plasma source 112, and which differ from one another in their inductance. For example, the inductance may decrease or increase in a direction away from the electrical connection. Alternatively or additionally, the inductance may decrease or increase along the coil axis.

[0104] According to implementation 300c, the distance of the electrical line 304, which provides the coil windings 312a, 312b, from the coil axis can vary locally. According to implementation 300c, the variable coil can be, for example, a conical coil. Alternatively or additionally, according to implementation 300d, the angle of the electrical line 304 relative to the coil axis can vary locally.

[0105] Other examples (not shown) for implementing a compensation element include adjusting one or more properties of the gas flow (e.g., spatial distribution, mixing, pressure difference, etc.) in such a way that this property counteracts the disruption of plasma formation. For example, a pressure gradient when admitting the process gas into the plasma region can be adjusted to counteract the disruption of plasma formation.

[0106] Other examples (not shown) for implementing a compensation element include mounting those components of the gas supply system (e.g., the housing) that capacitively interact with the plasma source in an electrically (e.g., galvanically) insulated manner, e.g., by electrically floating mounting. Alternatively or additionally, those components of the gas supply system (e.g., the housing) that capacitively interact with the plasma source can be dielectric.

[0107] Other examples (not shown) for implementing a compensation element include using a curved housing so that the path of the excited gas flow to the coating area is a function of the location of the plasma formation.

[0108] Fig. 4 illustrates a gas excitation device 100 according to various embodiments 400 (e.g., according to Examples 5, 7, and 10) in a schematic, semi-transparent perspective view. The gas excitation device 100 has two excitation coils 302a, 302b, each of which provides a portion of the plasma source 112 and which differ from one another in their winding sense. The two excitation coils 302a, 302b extend, for example, from the electrical connection 402 (also referred to as the feed point in this case) along the coil axis 477, at which the excitation frequency is coupled (e.g., by means of the excitation current).

[0109] In an exemplary implementation, the (e.g., electrically conductive) housing 404 is present. On the side of each of the excitation coils 302a, 302b opposite the electrical connection 402, the excitation coil 302a, 302b is coupled to electrical ground (also referred to as grounded) by means of the (e.g., electrically conductive) housing 404. It can be understood herein that any other reference potential can be used instead of electrical ground, and that what has been described for electrical ground applies analogously to the reference potential. Each of the two excitation coils 302a, 302b is optionally provided by means of a hollow conduit 304 through which a cooling fluid can flow during operation. In the case of grounding on both sides, a potential reduction path for the cooling fluid can be omitted.

[0110] As explained above, the gas supply 202 can be configured to distribute the process gas, which is supplied via a gas line 202g, and to supply it as a gas stream to the plasma region, which exits again through the gas outlet openings 204o. This gas stream through the plasma region 152 can be exposed to the excitation field during operation, so that it is ionized (i.e., has so-called activated gas).

[0111] An exemplary implementation according to Example 6 comprises that the electrical power to generate the excitation field is coupled into the terminal 402 by means of an electrical supply line 410 and an electrical return line 412, which distributes it to the two excitation coils 302a, 302b.

[0112] Fig.5 illustrates a vacuum arrangement 500 according to various embodiments (e.g., according to Example 13) in a schematic side view or cross-sectional view.

[0113] An exemplary implementation of the coating device is configured as a thermal evaporation device, e.g., an electron beam evaporation device. The evaporation device comprises a crucible 502 (also referred to as an evaporation crucible) and a heating device. In the case of the electron beam evaporation device, the heating device may comprise an electron beam gun 504 configured to generate an electron beam 504s and direct it onto the crucible 502. The coating material received in the crucible 502 can be converted into the gaseous state 506 by means of the heating device (e.g., the electron beam 504s), which propagates toward a transport device (e.g., to a transport surface 508 provided thereby).It can be understood that what is described for thermal evaporation devices can apply to any other coating device that is arranged to emit the coating material in the gaseous state towards the transport device (e.g. a transport roller thereof).

[0114] Alternative or additional examples of the coating device are configured to perform a PVD or CVD type coating process, such as cathode sputtering (also referred to as sputtering), arc evaporation, laser beam evaporation, or molecular beam epitaxy.

[0115] An exemplary implementation of the transport device is configured to transport a strip-shaped substrate (also referred to as a strip substrate) along the transport surface 508, e.g., from roll to roll. The transport surface 508 can, for example, be curved multiple times. For this purpose, the transport device has a plurality of transport rollers 510, by means of which the transport surface is deflected. Alternatively, the transport device is configured to transport a plate-shaped substrate.

[0116] One of the transport rollers 510, toward which the gaseous coating material spreads, can be configured, for example, as a cooling roller. The cooling roller can, for example, have a cooling device configured to extract thermal energy from the substrate.

[0117] The gas excitation device 100 can be configured to expose the gaseous coating material to the process gas 522 ionized by the plasma source. For this purpose, the gas outlet openings 204o can, for example, be directed toward the region along which the coating material propagates toward the transport device.

[0118] During operation, the vacuum arrangement 500 may include a power source 520 configured to supply the gas excitation device 100, e.g., its plasma source, with electrical power, e.g., by means of an alternating current. The power source 520 may, for example, include a high-frequency power supply and / or a matchbox (e.g., having a matching network).

[0119] Optionally, the vacuum assembly 500 may include one or more apertures 512 (e.g., a vapor aperture) that provide a passage through which the gaseous coating material 506 (also referred to as a vapor stream) is emitted toward the transport device. The aperture 512 may, for example, shield a portion of the transport device from the gaseous coating material.

[0120] In an exemplary implementation according to Example 16, the vacuum arrangement 500 comprises a vacuum chamber 802 in which the transport path 502 (at least in sections), the coating device and / or the gas excitation device are arranged.

[0121] Fig. 6 illustrates a method 600 configured according to various embodiments (e.g., according to Example 17) in a schematic flow diagram. The method 600 comprises, in 601, guiding a gas stream through a plasma region into a vacuum; in 603, inducing plasma formation in the plasma region through which the gas stream is guided, using at least one inductive plasma source; and preferably, in 603, coating a substrate using a coating material exposed to the gas stream guided out of the plasma region.

[0122] Analogously, according to various embodiments (e.g., according to Example 18), an inductive plasma source can be used to stimulate plasma formation in the plasma region through which a gas stream is passed, to which a coating material is preferably exposed, by means of which a substrate is coated. Additional implementations and uses according to various embodiments described herein are explained below.

[0123] An exemplary implementation of the gas excitation device comprises a primarily inductively coupled high-frequency plasma source for the excitation, dissociation, and ionization of reactive gas for a PVD process. The inductor of the plasma source is provided by a cylindrical coil arranged in a largely closed and electrically conductive housing (also referred to as a casing). The reactive gas is introduced into this housing, excited at elevated pressure by the inductor, and then emitted through openings in the housing toward the coating area on the substrate. Examples of the PVD process include: sputtering, vapor deposition, and metamode processes, as well as other processes in which, for example, the primary layer deposition and a secondary chemical reaction of the deposited layer occur sequentially.

[0124] To reduce the permeability of a polymer film as an exemplary substrate for gases (e.g., water vapor and / or oxygen), the polymer film can be vacuum-coated with one or more barrier layers. The coated polymer film can be used, for example, as optically transparent packaging for food or pharmaceuticals.

[0125] The coating process (by means of which, for example, the polymer film is coated) can be carried out in a vacuum (also referred to as a vacuum coating process). Variants of this that promote high productivity include evaporation processes, such as electron beam evaporation or boat evaporation. To deposit a barrier layer made of a chemical compound (e.g., oxide), such as aluminum oxide (also referred to as an aluminum oxide barrier layer), the vacuum coating process can be carried out reactively (also referred to as a reactive coating process).

[0126] An exemplary implementation of a reactive coating process involves evaporating metallic aluminum, for example, using an electron beam. Alternatively or additionally, oxygen can be added to the reactive coating process, which promotes the formation of an oxide layer on the substrate.

[0127] The process window of the reactive coating process for promoting high optical transparency and good barrier effect (e.g. with regard to the evaporation rate and / or oxygen flow) may be insufficiently narrow for stable production, resulting in the coating process being insufficiently robust. Outside the process window, the stoichiometry of the layer tends to deviate from the target value, so that the layer, for example, has metallic and thus low optical transparency or is too oxidic and thus too low a barrier effect. This process window can be extended by activating the reactive gas (e.g. oxygen), e.g. in such a way that stable production is promoted with reliable layer quality and / or over a long period of time, e.g. over the entire campaign duration or even over several consecutive campaign durations.

[0128] An exemplary implementation of the gas excitation device is elongated along the coil axis and has an internal cylindrical coil whose conductor is wound around the coil axis. The high-frequency power is fed in, for example, at a point on the coil located centrally in the longitudinal direction. The two coil halves that adjoin each other at this point can, for example, be wound in opposite directions, so that they differ in their winding direction. This promotes the generation of a collision-free magnetic field.

[0129] An exemplary implementation of the excitation frequency coupled to the plasma source may be in a range of approximately 10 megahertz (MHz) to approximately 100 MHz, e.g., 13.56 MHz or more, e.g., 27.12 MHz or more, e.g., 40.68 MHz or more.

[0130] In addition to the primarily effective, purely current-dependent and thus largely independent of the distance from the feed point, inductive excitation (e.g., plasma formation) can also occur in a weak form in some cases, for example, between the individual coil windings and between the coil windings and the electrically conductive housing (also known as the enclosure). The intensity of the latter depends on the electrical voltage on the respective coil element.

[0131] An exemplary implementation of the electrically conductive enclosure comprises or consists of a metal tube closed on both sides, which has, for example, an inner diameter of approximately 0.1 meter (m) or more, e.g., 0.2 m or more, and / or in a range of approximately 0.05 m (preferably 0.1 m) to approximately 0.5 m (preferably 0.25 m).

[0132] An exemplary implementation of the plasma source (e.g. its excitation coil) has a length along the coil axis of more than 1 m, e.g. 1.7 m or more, e.g. 2.5 m or more, e.g. 3.4 m or more. Alternatively or additionally, the exemplary implementation of the excitation coil has a pitch of the windings such that the spatial dependence of the capacitive coupling and the associated spatial dependence of the overall plasma excitation is compensated by the associated variation of the inductive component of the plasma excitation. This promotes very homogeneous plasma excitation even over a large overall distance of e.g. 1.7 m, 2.5 m or 3.4 m. Alternatively or additionally, a targeted spatial dependence of the plasma excitation can also be set in this way.

[0133] An exemplary implementation of the housing, for example, is electrically (e.g., ohmically) coupled to both ends of the plasma source (e.g., its excitation coil, e.g., in the form of a cylindrical coil). Any water cooling system for the plasma source (e.g., its excitation coil) can therefore be connected to ground potential on both sides, simplifying the design. A complex and technically vulnerable separate potential reduction system using insulating tubing in a vacuum is thus not necessarily required, saving material, installation space, and technical risk.

[0134] An exemplary implementation of the gas supply 202, which is configured to supply the process gas (e.g., a gas mixture) to the plasma region, e.g., into the housing, comprises a gas distribution pipe with multiple supply openings 202o (also referred to as outlet points) that open into the plasma region and / or are attached externally (e.g., in sections) to the electrically conductive housing at ground potential. Alternatively or additionally, the gas supply 202 can be integrated (e.g., in sections) into the housing or arranged therein, at least implemented by means of a distribution system.

[0135] An exemplary implementation of the gas discharge has several gas outlet openings arranged on a longitudinal side of the electrically conductive housing for the activated process gas in the direction of the transport device, or at least the condensation location of the coating material (also referred to as coating area) on the substrate.

[0136] Exemplary implementations of the gas outlet openings are provided in the form of bores, nozzles, slots, or in the form of a longitudinally continuous gap. The summed gas conductance of the gas discharge (e.g., its gas outlet openings) can be configured such that, at the desired process gas flow inside the enclosure, a desired pressure is provided that favors the ignition and operation of a plasma discharge. The desired pressure can, for example, be in a range of approximately 10 3 mbar to approximately 10 2mbar and / or greater than the pressure inside the vacuum chamber (or at least in the coating area).

[0137] An exemplary position and orientation of the gas excitation device near the coating area (the area, e.g., the transport surface, which is exposed to the gaseous coating material) is such that a direct vapor flow of the coating material toward the gas outlet is inhibited, e.g., blocked.

[0138] An exemplary implementation of the electrical connector is coupled to a supply line surrounded by a metallic return conductor, which connects the connector to the power source, for example. The return conductor can be installed between the electrically conductive environment and the matchbox. This minimizes the electromagnetic fields that are coupled into the vacuum chamber and / or the coating device during operation of the plasma source.

[0139] Various variations are explained below, for which the above description applies analogously.

[0140] Advantageously, in the case of a coating device in the form of an electron beam coating device, the gas excitation device (or at least its gas discharge) is arranged on a side of the crucible and / or the coating area opposite the electron beam source and / or the electron beam. This prevents the electron beam from being influenced.

[0141] Advantageously, the gas discharge 204 (e.g., its through-openings 204o) is configured to be adjustable, e.g., by means of an actuator configured to change the gas conductance of the gas discharge 204 (or at least the geometry of the through-openings 204o) and / or the direction in which the process material is discharged by means of the gas discharge 204. For example, the gas flow through the gas discharge 204 can be changed (e.g., inhibited or promoted), e.g., at least partially blocked, by means of the actuator, or at least a spatial distribution of the gas conductivity can be influenced. This facilitates adaptation of the gas discharge 204 to a change in the actual parameter of the coating process, such as, for example, a substrate width, a substrate position, and / or a flow of gaseous coating material.Alternatively or additionally, the direction in which the process material is discharged via the gas discharge 204 (or at least each of the gas outlet openings 204o) can be changed, so that the process gas (illustratively, the discharge flow of excited gas particles) is discharged according to a desired spatial distribution via the gas discharge 204 (e.g., each of the gas outlet openings 204o), e.g., directed toward a desired area of ​​the coating window. This makes it possible to promote or inhibit an inhomogeneity of the layer caused by the gas flow and / or the plasma excitation (e.g., a gradient in the layer composition).

[0142] In the following, properties of various embodiments are explained which address the aspects described above.

[0143] Providing a linear and / or easily scalable gas excitation device, e.g. scalable for a small (e.g. 0.5 m) or very large (e.g. 2.85 m) activation coating width.

[0144] Reduction of installation space and / or the number of electrical power sources across the entire width.

[0145] Efficient gas excitation by inductive plasma excitation (e.g. inductively coupled plasma) in a spatially separated plasma region (also called discharge region) in which an increased gas pressure can be provided.

[0146] Reduction of the effect of a plasma on the substrate and / or the layer formed thereon, which is particularly advantageous for forming a sensitive layer and / or coating a sensitive substrate.

[0147] Reduction of the emission of a high-frequency electromagnetic field into the vacuum chamber.

[0148] Robust design of the gas excitation device, for example, without wearing parts, which extends service life. Various working examples are described below, which relate to what is described herein and illustrated in the figures.

[0149] According to a working example 1, which is configured according to one of examples 1 to 54, the electromagnetic coil is degenerated into a tubular geometry (then also referred to as a tubular coil). The tubular coil is penetrated along the coil axis by a through-opening in which the plasma region is arranged. The through-opening is delimited by a tubular wall (also referred to as a tubular wall), which can be C-shaped, for example. The tubular coil has exactly one coil turn, which is formed by the tubular wall. For example, the tubular wall can be a C-shaped plate. C-shaped can be understood in this context as that two immediately adjacent end sections of the tubular wall, which face each other, are spatially separated from one another. For example, the tubular coil can be provided by means of a tube that is interrupted by a gap.The gap extends along the coil axis and can, for example, separate two immediately adjacent end sections of the tube wall that face each other.

[0150] Fig. 3E illustrates a gas excitation device 100 according to various embodiments 300e (e.g., according to Example 35) in a schematic circuit diagram and / or schematic positioning diagram. Direction 105 can, for example, be parallel to the direction of the gas flow through the plasma region 152. The electromagnetic coil configured as a tubular coil has a (e.g., linear or curved) coil axis and a wall-shaped electrical line 304 (e.g., tubular wall) curved around the coil axis and providing exactly one coil turn (see, for example, Fig. 3E). The electrical line 304 has two immediately adjacent end portions that face each other and are separated from each other by a gap 304s.

[0151] According to a working example 2, which is configured according to any one of examples 1 to 54, the plasma source has several counter-oriented coil-shaped inductors arranged side by side. This reduces the generated far field and can be advantageous if the tube shielding (induction - counter field) and a usable MU-metal sheath are insufficient. The reduced far field facilitates, for example, the use of the gas excitation device for a gas flow on target material generated by electron beam evaporation. Clearly, the reduced far field interferes with the electron beam less.

[0152] Fig. 3F illustrates a gas excitation device 100 according to various embodiments 300f (e.g., according to Example 37) in a schematic circuit diagram and / or schematic positioning diagram. Direction 105 can, for example, be parallel to the direction of the gas flow through the plasma region 152. Two first electromagnetic coils 302a, 302b arranged one behind the other along a first coil axis are coupled to one another by means of the feed point 402 and coincide in their winding sense. Next to these are two second electromagnetic coils 302c, 302d arranged one behind the other along a second coil axis, which are coupled to one another by means of the feed point 402 and coincide in their winding sense. For example, the first electromagnetic coils (e.g., their windings) 302a, 302b can continue one another. Alternatively or additionally, the second electromagnetic coils 302c, 302d (e.g.,their windings) continue each other.

[0153] An exemplary implementation of the windings of the two first electromagnetic coils 302a, 302b differ in their winding sense from the windings of the two second electromagnetic coils 302c, 302d.

[0154] According to a working example 3, which is configured according to any one of examples 1 to 54, the or each electromagnetic coil (e.g., its electrical conductor) comprises aluminum and / or is coated with an oxide (or other ceramic or dielectric). The oxide may be, for example, aluminum oxide or magnesium oxide. This increases the coil's resistance to material-erosive interaction with the plasma. In this regard, it is understood that the coil(s) may be coated with or consist of any other difficult-to-sputter material.

[0155] According to a working example 4, which is configured according to any one of examples 1 to 54 (e.g., according to example 41), the plasma source comprises one or more than one coil winding (or coil) provided by means of a tubular fluid conduit. The fluid conduit has a cavity for receiving a (e.g., liquid) cooling fluid (e.g., water). In this case, the plasma source may additionally comprise two fluid connections, which are fluidly coupled to one another by means of the fluid conduit. This facilitates the cooling of the plasma source. The fluid connections may, for example, be connected to a cooling device configured to extract thermal energy from the plasma source by means of the cooling fluid.

[0156] According to a working example 5, which is configured according to any one of examples 1 to 54 (e.g., according to example 42), a wall of the housing (also referred to as the gas outlet wall) is penetrated by the gas outlet openings, which are arranged offset from the coil windings such that the distance between each gas outlet opening and the coil windings is as large as possible. This inhibits disruptive plasma formation through the gas outlet openings. For example, each gas outlet opening can continue a region (which extends from the gas outlet opening toward the coil axis and / or along the flow direction) that is arranged between two coil windings. Alternatively or additionally, each gas outlet opening can be arranged outside a contour of the coil windings of the plasma source projected onto the gas outlet wall (e.g., along the flow direction 105).

[0157] Fig. 7 illustrates a gas excitation device 100 according to various embodiments 700 (e.g., according to Example 37) in a schematic projection view onto the gas outlet wall 704, which is penetrated by the gas outlet openings 204o along one direction (also referred to as the gas outlet direction) (e.g., flow direction 105). Line 702 represents the contour of the coil windings projected onto the gas outlet wall 704. The projection can be along the gas outlet direction, which can be, for example, the flow direction 105. In this regard, it can be understood that not every gas outlet opening 204o necessarily has to be arranged in this way, but the more gas outlet openings 204o are arranged in this way, the more favorable it is.

[0158] More generally, each coil winding may have a first distance 702d (also referred to as winding-to-wall distance 702d) from the gas outlet wall 704 and a second distance from the gas outlet opening 204o immediately adjacent thereto, wherein the second distance is at least 110% of the first distance 702d (e.g., at least 120% thereof, e.g., at least 130% thereof, e.g., at least 150% thereof).

[0159] According to a working example 6, which is configured according to any one of examples 1 to 54 (e.g., according to example 45), a wall of the housing (also referred to as gas outlet wall) is penetrated by the gas outlet openings and covered by a gas-permeable protective wall. The protective wall is further electrically conductive and / or grounded. This inhibits disruptive plasma formation through the gas outlet openings. The housing wall is arranged between the protective wall and the plasma source, for example, such that each gas outlet opening is directed toward multiple openings in the protective wall and / or toward a fixed portion of the protective wall. Exemplary implementations of the metallic protective wall include a mesh, a grid, a perforated plate, or a network of multiple filaments. The protective wall has multiple openings per gas outlet opening of the gas outlet openings.

[0160] According to a working example 7, which is configured according to any one of examples 1 to 54, a dielectric tube is present which is penetrated (e.g. along the flow direction) by a plurality of openings (also referred to as gas passage openings) and in which the plasma formation takes place. The tube can, for example, be arranged inside a coil or between two coils or in such a way that a coil axis runs inside the tube. The tube inhibits a material-removing interaction of the plasma with the coil. In the case of a plurality of coils arranged one behind the other along the coil axis, a plurality of tubes, e.g. one tube per coil, can also be present, which continue one another along the coil axis.

[0161] Fig. 8 illustrates a gas excitation device 100 according to various embodiments 800 (e.g., according to Example 53) in a schematic cross-sectional view along the coil axis 477. One or more electromagnetic coils 302a and, furthermore, e.g., per coil, the tube 802 made of a dielectric (also referred to as a dielectric tube) can be arranged in the housing 404. The distance between the tube and the housing can, for example, be smaller than the diameter of the coil 302a. The dielectric can, for example, be an oxide or another ceramic.

[0162] Furthermore, a plurality of gas passage openings may be present, each gas passage opening penetrating the tube along a direction toward the coil axis 477. The plurality of gas passage openings may, for example, have at least one gas passage opening 802a per gas outlet opening 204o, which is directed toward the gas outlet opening 204o. Furthermore, the plurality of gas passage openings may, for example, have at least one gas passage opening 802i per supply opening 202o, which is directed toward the supply openings 202o.

[0163] According to a working example 8, which is configured according to any one of examples 1 to 54, a cooling device is provided which is configured to extract thermal energy from the housing and / or the plasma source, e.g., by means of a cooling fluid. For this purpose, the housing and / or the plasma source, e.g., the coil(s) thereof, can have one or more fluid lines for receiving the cooling fluid.

[0164] According to a working example 9, which is configured according to any one of examples 1 to 54, the housing is electrically conductive (e.g., metallic) and is subjected to a (e.g., pulsed) direct voltage that differs from the ground potential of the coating device. This promotes the transport of ions out of the housing.

Claims

Patent claims 1. Gas excitation device (100), comprising: • a plasma region (152); • a gas guide system (110) which is arranged to guide a gas flow through the plasma region (152), • one or more than one electromagnetic coil as an inductive plasma source (112), which is arranged to stimulate plasma formation in the plasma region (152), each coil having at least one winding around a coil axis of the coil which is transverse to a direction of the gas flow.

2. Gas excitation device (100) according to claim 1, wherein the inductive plasma source (112) is configured to couple an alternating electromagnetic field into the plasma region (152), preferably the gas stream passed through it, in order to stimulate plasma formation in the plasma region (152).

3. Gas excitation device (100) according to claim 1 or 2, wherein the gas guide system is arranged to guide a gas flow through the plasma region along a direction (105) which is transverse to a coil axis of the coil.

4. Gas excitation device (100) according to one of claims 1 to 3, wherein the gas guide system (110) comprises: • a gas discharge opening into the plasma region (152) for discharging the gas flow out of the plasma region (152); • wherein the gas discharge preferably has a series of several gas outlet openings arranged one behind the other.

5. Gas excitation device (100) according to claim 4, further comprising: • a housing in which the plasma region (152) and the inductive plasma source (112) are arranged; • wherein a wall of the housing is penetrated along the direction of the gas outlet openings; • wherein each coil winding of the plasma source has a first distance from the wall and a second distance from a gas outlet opening of the gas outlet openings immediately adjacent to the coil winding, which second distance is greater than the first distance.

6. Gas excitation device (100) according to claim 5, further comprising a voltage supply which is arranged to apply a DC voltage, which is preferably pulsed, to the housing.

7. Gas excitation device (100) according to one of claims 1 to 6, further comprising: • a compensation element configured to compensate for a first spatial variation of the plasma formation excited by a first portion of the plasma source (112); wherein the compensation element is preferably implemented by a second spatial variation of one or more of the following: • the formation of plasma, which is stimulated by means of a second section of the plasma source (112); • a gas conductivity of the gas supply system (110); • a path of the gas guidance system (110) along which the gas flow is guided away from the plasma region (152).

8. Gas excitation device (100) according to one of claims 1 to 7, wherein the inductive plasma source (112) has a spatial variation along the coil axis of one or more than one of the following: • an inductance of immediately adjacent coil windings; • a winding direction of adjacent coil windings.

9. Gas excitation device (100) according to one of claims 1 to 8, wherein the coil axis is transverse to the direction of the gas flow in which the gas flow leaves the plasma region.

10. Gas excitation device (100) according to one of claims 1 to 9, wherein the coil is cylindrical.

11. Gas excitation device (100) according to one of claims 1 to 10, wherein the more than one coil comprises two coils which are coupled to one another by means of an electrical connection (402) as a feed point arranged between the two coils.

12. Gas excitation device (100) according to one of claims 1 to 11, wherein the coil is provided by means of a fluid conduit having a cavity for receiving a cooling fluid.

13. Vacuum arrangement (500), comprising: • a coating device which is arranged to coat a substrate in a vacuum by means of a coating material; • the gas excitation device (100) according to one of claims 1 to 7, which is arranged to expose the coating material to the gas stream emerging from the plasma region (152).

14. Method (600), comprising: • guiding (601) a gas stream through a plasma region (152) into a vacuum; • Excitation (603) of a plasma formation in the plasma region (152) through which the gas flow is passed, by means of an alternating electromagnetic field which is generated by means of the one or more than one electromagnetic coil as an inductive plasma source (112), each coil having at least one winding around a coil axis of the coil which is transverse to a direction of the gas flow.

15. Using one or more than one electromagnetic coil as an inductive plasma source (112) for stimulating plasma formation in a plasma region (152) through which a gas stream is passed, to which a coating material is preferably exposed, by means of which a substrate is coated, each coil having at least one winding around a coil axis of the coil which is transverse to a direction of the gas stream.

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