Apparatus, control device, and method for laser-induced arc evaporation

Abstract

Apparatus, control devices, and methods for laser-induced arc evaporation are provided. According to various embodiments, the method may include controlling a laser source (110) and a power supply (118) according to an operating sequence, the operating sequence comprising several phases, in each phase, the laser source generates an excitation pulse directed at a target (112) to excite an arc discharge at the target, the power supply (118) generates a first power pulse (120) to power the arc discharge, and / or the power supply (118) generates a second power pulse (122) generated by the power supply (118). The material flow (116) emitted from the target by arc discharge is accelerated away from the target, and the plurality of phases include one or more first phases, each first phase in which a first power pulse (120) and / or a second power pulse (122) is generated for each excitation pulse, and a second phase in which two excitation pulses (114) and / or two first power pulses (120) are generated for each second power pulse (122).

Description

Technical Field

[0001] Various embodiments relate to apparatuses such as vacuum assemblies, control apparatuses, and methods for laser-induced arc evaporation.

Background Art

[0002] Generally, a substrate (e.g., a workpiece) can be coated such that the chemical and / or physical properties of the substrate can be changed. The coating of the substrate may be performed in a vacuum, and one or more layers are deposited on the substrate by physical vapor deposition. An economical and technically attractive method for physical vapor deposition is known as arc evaporation, in which the material is evaporated by an arc discharge. However, currently, there are very few materials and layer structures suitable for arc evaporation, which is why the potential of arc evaporation cannot usually be fully utilized. This also applies to other types of evaporation using plasma, and here, arc evaporation is referred to as an example.

[0003] [[ID=*16]]The problems arising from this background are solved by the various embodiments provided herein and the aspects described herein.

Summary of the Invention

Means for Solving the Problems

[0004] According to various embodiments, it has been recognized that arc evaporation provides additional leeway in the selection of the operating point in order to affect the properties of the resulting coating, especially when there are additional opposing requirements. These include, for example, requirements due to temperature-sensitive substrates, requirements for the properties of the coating, and / or requirements for productivity.

[0005] Various embodiments relate to apparatuses such as vacuum devices, control devices, and methods (e.g., for laser-induced arc evaporation) that broaden the range for selecting the operating point (OP) of arc evaporation.

[0006] This makes it easier to reduce the effects of arc evaporation, such as high evaporation rates and / or a high degree of excitation and / or ionization of the resulting material vapor. This makes it easier to reduce the energy input to the substrate (e.g., a bipolar plate) when coating the substrate (e.g., with carbon), thereby suppressing excessive heating of the substrate and minimizing associated losses in layer properties and / or productivity.

[0007] Various examples related to those described and shown in this specification are listed below.

[0008] For ease of understanding, we refer to laser-excited arc discharge (also known as laser-induced arc discharge) as an example of pulsed-excited plasma discharge in which an arc discharge is excited by a laser pulse. The description provided herein may be understood to be analogous to any other type of pulsed-excited plasma discharge, such as pulsed sputtering, which does not necessarily have to be an arc discharge and / or does not necessarily have to be excited by a laser pulse (see Examples 53 and 54 below).

[0009] Example 1 is a method (for example, for performing laser-induced arc evaporation) comprising the steps of controlling an excitation source (e.g., a laser source) according to an operating sequence (e.g., carried out by a stored code segment), and controlling a power supply according to the operating sequence, wherein the operating sequence preferably comprises several phases, in each of which preferably an excitation pulse (e.g., a laser pulse) directed toward a target is generated by the excitation source (e.g., a laser source) to excite a plasma discharge (e.g., an arc discharge) in the target, a first power pulse is generated by the power supply to electrically supply the plasma discharge (e.g., an arc discharge) by the target, and / or a second power pulse is generated by the power supply to move a material flow emitted from the target by the plasma discharge (e.g., an arc discharge) away from the target and / or toward a substrate holder (e.g., by which, for example, a bipolar plate is held) (e.g., an ionization portion).

[0010] Here, the operating sequence is understood to be a specification in which one or more operating members configured to influence the generation of a plasma discharge (e.g., an arc discharge) are controlled. The operating sequence may specify one or more setpoint parameters that generate the first and / or second power pulses and / or excitation pulses (e.g., laser pulses). Examples of such parameters include frequency, total power, pulse shape, pulse duration, and pulse (temporal) delay (e.g., time offset).

[0011] Example 2 is configured according to Example 1, wherein a first power pulse is transmitted by the target and / or an anode associated with the target, and / or a second power pulse is transmitted by the substrate holder to which the material flow is directed and / or an anode associated with the substrate holder. For example, a reference potential such as electrical ground (also called ground potential) may be applied to the anode.

[0012] Example 3 is configured according to Example 1 or 2, wherein the plurality of phases comprises one or more first phases (also called first type phases) in which, in each first phase, a first power pulse and / or a second power pulse is generated for each excitation pulse (e.g., a laser pulse), and the plurality of phases comprises a second phase (also called second type phase) in which at least two (i.e., two or more) excitation pulses (e.g., laser pulses) and / or at least two (i.e., two or more) first power pulses are generated for each second power pulse.

[0013] Example 4 is configured according to Example 3, where each of the multiple phases in the second phase includes at least two or three of the first phases.

[0014] Example 5 is configured according to one of Examples 1 to 4, and the first power pulse is generated according to a target pulse length in the range of about 30 μs to about 600 μs, preferably in the range of about 150 μs to about 350 μs.

[0015] Example 6 is constructed according to one of Examples 1 to 5, and the first power pulse is generated according to a target pulse length in the range of approximately 250 μs to approximately 350 μs.

[0016] Example 7 is constructed according to one of Examples 1 to 6, where a first power pulse is generated according to a target current pulse (e.g., amplitude, duration, gradient, etc.), and / or a second power pulse is generated according to a target voltage pulse (e.g., amplitude, duration, gradient, etc.).

[0017] Example 8 is configured according to one of Examples 1 to 7, wherein each phase of the operating sequence is configured such that a first power pulse is generated according to a target pulse frequency, and the ratio of the target pulse frequency to the actual length of the target is in the range of about 400 Hz / m (e.g., 750 Hz / m) to about 2500 Hz / m (e.g., 2000 Hz / m), preferably in the range of about 1200 Hz / m to about 2000 Hz / m, and more preferably in the range of about 1200 Hz / m to about 1600 Hz / m.

[0018] Example 9 is configured according to one of Examples 1 to 8, wherein the second power pulse includes a target peak value in the range of about 300V to about 1500V (e.g., 1000V), preferably in the range of about 500V to about 1000V, and more preferably in the range of about 700V to about 900V.

[0019] Example 10 is constructed according to one of Examples 1 to 9, wherein the first power pulse is generated according to a target pulse shape (as a target time dependence of power), which includes, for example, a sinusoidal pulse shape, a square pulse shape, or a triangular pulse shape (see also Figure 3), and / or an asymmetrical pulse shape.

[0020] For example, the peak value of an asymmetric triangular pulse shape may be reached approximately 65% ​​of the pulse duration. Alternatively or additionally, the falling edge of an asymmetric pulse shape may be as short as possible.

[0021] The contribution of the falling edge to the integrated current of an asymmetric pulse (also called the current pulse integral) may be smaller than, for example, the contribution of the rising edge to the current pulse integral (e.g., about 50%). The contribution of the falling edge to the integrated power of an asymmetric pulse (also called the power pulse integral) may be smaller than, for example, the contribution of the rising edge to the power pulse integral (e.g., about 25%).

[0022] A triangular pulse shape is understood as the time dependence of a pulse where the rising and / or falling edges of the pulse have a constant slope (e.g., the same slope). The peak value may, but may not necessarily, be reached after half the pulse duration.

[0023] The sinusoidal pulse shape is understood to be the time dependence of the pulse, which can be essentially described by a sinusoidal function. For example, the rising and / or falling edges in the direction of the peak value may have a decreasing slope that approaches zero towards the peak value.

[0024] Example 11 is configured according to Example 10, and the power supply includes an output filter configured to be controlled in response to a desired pulse shape in order to affect the time dependence of the power pulse.

[0025] Example 12 is constructed according to one of Examples 1 to 11, and the first power pulse is generated according to a desired time dependency including a gradient ranging from about 5 MA / s (megaamperes per second) to about 150 MA / s, for example from 5 MA / s to about 70 MA / s, for example from 10 MA / s to about 24 MA / s.

[0026] Example 13 is constructed according to one of Examples 1 through 12, and the target contains or consists of carbon.

[0027] Example 14 is constructed according to one of Examples 1 to 13, wherein a first power pulse and a second power pulse are generated in at least one of the multiple phases (e.g., each) phase, and these pulses overlap only partially (in time).

[0028] Example 15 is configured according to Example 14, wherein in at least one of the multiple phases (e.g., each) phase, the second power pulse is generated with a time offset (also called a target time offset and / or target time delay) relative to the first power pulse, and / or, in at least one of the multiple phases (e.g., each) phase, the first power pulse is generated according to a first target time difference (also called a first target time delay) (e.g., first target time delay = 0) from the start of at least one phase, and the second power pulse is generated according to a second target time difference (also called a second target time delay) (e.g., second target time delay > 0, e.g., max 500 μs, e.g., max 100 μs) from the start of at least one phase, where the second target time difference is greater than the first target time difference. Alternatively or additionally, the target interval may correspond to twice the duration of the first power pulse.

[0029] For example, a second power pulse in at least one phase may begin before or after the first power pulse.

[0030] Example 16 is configured according to Example 14 or 15, wherein the second power pulse is generated at least one phase after the first power pulse (for example, according to the target time offset).

[0031] Example 17 is constructed according to one of Examples 14 to 16, where a first power pulse is generated according to a first target pulse duration, and a second power pulse is generated according to a second target pulse duration such that the second power pulse ends (temporarily) before the first power pulse.

[0032] Example 18 is configured according to one of Examples 14 to 17, wherein a first power pulse and a second power pulse are generated such that the second power pulse starts after the first power pulse and / or ends before the first power pulse.

[0033] Example 19 is a computer program that, when executed by a processor, is configured to cause the processor to perform any of the methods relating to Examples 1 through 18.

[0034] Example 20 is a computer-readable medium that, when executed by the processor, stores instructions for the processor to perform any of the methods relating to Examples 1 through 18.

[0035] Example 21 is a control device comprising one or more processors configured to perform the method according to any one of Examples 1 to 18.

[0036] Example 22 is an apparatus (e.g., a vacuum assembly) comprising the control device described in Example 21, a power supply, an excitation source (e.g., a laser source), and a target holder for holding a target, wherein the target holder is electrically coupled to the power supply and is configured to optionally provide a rotation axis and rotate the target around the rotation axis.

[0037] Example 23 is configured according to Example 22 and further comprises a vacuum chamber coupled to an excitation source (e.g., a laser source) and a power supply, in which a target holder is placed.

[0038] Example 24 is configured according to Example 22 or 23 and further comprises a substrate holder that is coupled to a power supply and optionally placed inside a vacuum chamber.

[0039] Example 25 is configured according to Example 24, and the distance between the rotation axis (or target held in the target holder) and the substrate holder is in the range of approximately 200 mm (e.g., 410 mm) to approximately 750 mm or less.

[0040] Example 26 is configured according to one of Examples 22 to 25 and further comprises a transport device for transporting a substrate along a transport path that passes through a target holder.

[0041] Example 27 is configured according to one of Examples 22 to 26 and further comprises a particle filter positioned between a target holder and a substrate holder, configured to filter the flow of material emitted from the target by a plasma discharge (e.g., an arc discharge).

[0042] Example 28 is configured according to one of Examples 22 to 27 and further comprises an anode coupled to a power supply.

[0043] Example 29 is configured according to one of Examples 22 to 28, wherein the target holder is configured to drive rotational motion (for example, the target holder includes a drive device, e.g., an electric motor, configured to apply torque to the target).

[0044] Example 30 is configured according to Example 29, and the (e.g., target) frequency of the rotational motion is in the range of about 10 revolutions per minute to about 40 revolutions per minute, preferably in the range of about 20 revolutions per minute to about 30 revolutions per minute.

[0045] Example 31 is a method comprising the steps of: placing (e.g., transporting) a bipolar plate (e.g., made of metal) in a vacuum; and performing pulse-induced (e.g., laser-induced) arc evaporation (e.g., as a plasma discharge) in a vacuum, as configured according to Example 13, by controlling an excitation source (e.g., a laser source) and a power supply according to a method according to one of Examples 1 to 18 (e.g., by an apparatus according to one of Examples 22 to 30), wherein the material flow emitted by the plasma discharge (e.g., arc discharge) includes carbon emitted toward the bipolar plate.

[0046] Bipolar plates (also called electrode plates) are used, for example, in fuel cells. In fuel cells, several membrane electrode assemblies may be configured in a stacked configuration. A bipolar plate may be configured between two adjacent membrane electrode assemblies. This can help separate gases between two adjacent membrane electrode assemblies. A bipolar plate may have, for example, one or more (e.g., meandering) channels (e.g., in the form of trenches) (e.g., in the form of flow profiles) through which the reaction gases, oxygen and hydrogen, can be supplied to their respective membrane electrode units. Multiple channels may function to uniformly distribute the reaction gases. Furthermore, water produced during the reaction can be removed (e.g., as water vapor) through channels in the bipolar plate. These channels may be milled or pressed on both sides of the bipolar plate, for example.

[0047] The metal bipolar plate may be conductive and therefore may function as a conductive connection between the anode of one adjacent film electrode assembly and the cathode of the other adjacent film electrode assembly. (e.g., metal) The high conductivity of the bipolar plate (e.g., 10 5To achieve a density greater than S / m, these may be coated with a carbon layer as described herein. Such bipolar plates can be used, for example, in proton exchange membrane fuel cells (PEM fuel cells). For example, the metal bipolar plates may contain or consist of steel (e.g., 316L and / or 304L type) and / or titanium. Alternatively or additionally, the metal bipolar plates (e.g., steel) may be coated with titanium, or may be made to be coated with titanium. The native oxide layer may be removed, for example, before coating.

[0048] Optionally, the proton exchange membrane of the bipolar plate may be coated with a catalyst such as platinum or palladium, or may be made to be coated. Optionally, the bipolar plate may have a mounting structure (e.g., having one or more through-holes) in its edge region to which the bipolar plate can be attached.

[0049] Example 32 is constructed according to Example 31, and the carbon layer is formed on the bipolar plate by material flow.

[0050] Example 33 is configured according to Example 31 or 32, and the vacuum is provided by a vacuum chamber comprising, for example, two substrate transport openings through which a bipolar plate is transported, with a coating region between which a material flow is released.

[0051] Example 34 is configured according to Example 33, and the control and transport are configured in relation to each other such that the (e.g., dynamic) rate at which the carbon layer is formed on the bipolar plate (i.e., amount of material / time) (also called the carbon layer coating rate) is 50 nm m / min or more.

[0052] Example 35 is configured according to Example 34 and further includes the step of performing an additional pulse-induced (e.g., laser-induced) plasma evaporation (e.g., arc evaporation) in a vacuum by additionally controlling an additional excitation source (e.g., laser source) and an additional power supply according to one of Examples 1 to 34, configured according to the method of claim 13, such that an additional carbon layer is formed between the carbon layer and the bipolar plate, the additional control and transport are configured relative to each other such that the additional rate (amount of material / time) (also called the coating rate of the additional carbon layer) at which the additional carbon layer is formed is less than 50 nm m / min and / or less than the coating rate of the carbon layer.

[0053] Example 36 is configured according to one of Examples 31 to 35, wherein a bipolar plate is coated with a titanium layer when pulse-induced (e.g., laser-induced) plasma evaporation (e.g., arc evaporation) is performed, and the titanium layer is optionally formed in a vacuum by, for example, physical deposition (e.g., sputtering process) before pulse-induced (e.g., laser-induced) plasma evaporation (e.g., arc evaporation) is performed.

[0054] Example 37 is constructed according to Example 36, and a coating process is performed to form a titanium layer on a bipolar plate before plasma evaporation, e.g., arc evaporation (e.g., before forming the carbon layer).

[0055] Example 38 is constructed according to Example 36 or 37, and the titanium layer is formed by magnetron sputtering, plasma evaporation (e.g., arc evaporation), or high-pulse magnetron sputtering.

[0056] Example 39 is constructed according to one of Examples 36 to 38, and the titanium layer has a thickness in the range of about 20 nm to about 400 nm, preferably in the range of about 50 nm to about 150 nm.

[0057] Example 40 is constructed according to one of Examples 36 to 39 and further includes plasma etching the surface of the bipolar plate on which the titanium layer will be formed, before forming the titanium layer.

[0058] Example 41 is constructed according to one of Examples 31 to 40, wherein the bipolar plate has a surface roughness having an arithmetic mean height of 0.3 μm or less, preferably 0.2 μm or less, and / or a maximum height of 4.0 μm or less, preferably 2.5 μm or less.

[0059] Example 42 is a bipolar plate having a carbon layer and / or an additional carbon layer formed according to one of the methods from Examples 31 to 41.

[0060] Example 43 is constructed according to one of Examples 1 to 42, wherein the carbon layers, carbon layers, and / or additional carbon layers (formed, for example, by material flow) have a layer thickness in the range of about 10 nm to about 150 nm, preferably in the range of about 20 nm (e.g., 30 nm) to about 90 nm.

[0061] Example 44 is constructed according to one of Examples 1 to 43, with a carbon layer (formed, for example, by material flow) and / or an additional carbon layer of 10 mΩ·cm 2 Preferably, 1 mΩ·cm 2 Preferably, 0.5 mΩ·cm 2 (For example, 0.3 mΩ·cm) 2 ), and / or 0.1 mΩ·cm 2 Includes ultra-high surface contact resistance.

[0062] Example 45 is constructed according to one of Examples 1 to 44, wherein the carbon content of the carbon layer (e.g., formed by material flow) and / or additional carbon layer is greater than about 90%, preferably greater than about 95%, and more preferably greater than about 99%.

[0063] Example 46 is constructed according to one of Examples 1 to 45, wherein the carbon layer (formed, for example, by material flow) and / or the additional carbon layer has at least 60%, preferably at least 80%, and more preferably at least 95% of the carbon as sp 2 They are mixed together.

[0064] Example 47 is constructed according to one of Examples 1 to 46, wherein the carbon layer (formed, for example, by material flow) and / or additional carbon layer has a resistivity of 1 Ω·cm or less, preferably 0.1 Ω·cm or less.

[0065] Example 48 is constructed according to one of Examples 1 to 47, wherein the carbon layer (formed, for example, by material flow) and / or additional carbon layer have a contact angle to water of 60° or more, preferably 85° or more, and more preferably 100° or more.

[0066] Example 49 is constructed according to one of Examples 1 to 48, wherein the carbon layer (e.g., formed by a material flow) and / or the additional carbon layer (e.g., formed by a material flow) has a refractive index in the range of about 2.0 to about 3.5, preferably in the range of about 2.5 to about 3.0, at a wavelength of about 0.5 μm.

[0067] Example 50 is constructed according to one of Examples 1 to 49, wherein the carbon layer (e.g., formed by a material flow) and / or additional carbon layer has a refractive index in the range of about 2.0 to about 5.0, preferably in the range of about 2.5 to about 3.5, at a wavelength of about 1 μm.

[0068] Example 51 is constructed according to one of Examples 1 to 50, wherein the carbon layer (formed, for example, by a material flow) and / or additional carbon layer has an average reflectance of 0.5 μm or less, preferably 0.3 μm or less, at a wavelength of about 0.5 μm.

[0069] Example 52 is constructed according to one of Examples 1 to 51, wherein the carbon layer (formed, for example, by material flow) and / or additional carbon layer have a nanohardness in the range of about 10 GPa to about 80 GPa, preferably in the range of about 20 GPa to about 70 GPa, and more preferably in the range of about 30 GPa to about 50 GPa.

[0070] Example 53 is one of Examples 1 to 52, wherein the excitation source includes a laser source configured to generate a laser pulse (e.g., directed towards a target) as an excitation pulse, and / or the plasma discharge includes an arc discharge, and / or the plasma evaporation includes an arc evaporation.

[0071] Example 54 is one of Examples 1 to 52, wherein the excitation source includes a power supply configured to generate a power pulse (e.g., directed towards a target) as an excitation pulse, and / or the plasma discharge includes a glow discharge, and / or the plasma evaporation includes sputtering (i.e., atomization by plasma), e.g., pulsed magnetron sputtering, e.g., high-energy pulsed magnetron sputtering (HiPIMS). In the context of glow discharge, for example, a discharge pulse including an excitation pulse and a first power pulse may be provided, which, for example, merge with each other. The excitation pulse may excite a voltage breakdown that merges with the plasma discharge supplied by the first power pulse, for example.

[0072] Example 55: A method (for example, according to one of Examples 1 to 54) comprising the steps of controlling an excitation source according to an operating sequence and controlling a power supply according to an operating sequence, wherein the operating sequence comprises several phases, in each phase, an excitation pulse (114) directed toward a target (112) is generated by an excitation source (110) to excite a plasma discharge at the target (112), a first power pulse (120) is generated by a power supply (118) to power the plasma discharge through the target (112), and / or a second power pulse (122) is generated by the plasma discharge away from the target (112) and / or toward the substrate holder (104). A method comprising: controlling a power supply generated by a power supply (118) to accelerate a material flow (116) emitted from a target (112); and updating an operating sequence based on the results of a plasma discharge, wherein the operating sequence is updated to include a plurality of phases comprising one or more first phases in which a first power pulse (120) and / or a second power pulse (122) is generated for each excitation pulse (114); a second phase in which two excitation pulses (114) and / or two first power pulses (120) are generated for each second power pulse (122); and / or generating first and second power pulses that partially overlap each other.

[0073] Example 56 is one of Examples 1 to 55 and further includes determining an operating sequence (e.g., forming and / or updating) based on the results of a plasma discharge, for example, based on the results of a coating process performed by the plasma discharge, wherein determining the operating sequence preferably includes determining one or more first phases (e.g., forming and / or updating) and / or determining one or more second phases (e.g., forming and / or updating). Determining the operating sequence may include, for example, determining the ratio of the first phases (e.g., the number of the first phases) to the second phases (e.g., the number of the second phases). Determining the operating sequence may include, for example, determining the ratio (e.g., the number, duty cycle, and / or power) of the excitation pulse (e.g., the number, duty cycle, and / or power) to the power pulses (e.g., the first power pulse and / or the second power pulse) for each second phase. Determining the operating sequence may include, for example, determining the overlap between the first power pulse and the second power pulse (e.g., expressed as overlap time and / or overlap integral). Determining the operating sequence may also include, for example, determining the state (e.g., power, time distribution, e.g., duration and / or start time, amplitude, etc.) of one or more power pulses (e.g., the first power pulse and / or the second power pulse).

[0074] Example 57 is one of Examples 1 to 56, in which the determination of the operating sequence is based on the result of a coating process performed by plasma discharge (e.g., as a result of plasma discharge) and / or the determination of the operating sequence is based on the state of the substrate exposed to plasma discharge (e.g., as a result of plasma discharge). This state may be, for example, the temperature of the substrate (e.g., its change) and / or its properties (e.g., its change).

[0075] Example 58 is one of Examples 1 to 57, configured according to one of the appended claims (e.g., 1 to 16), and / or one of the appended claims (e.g., 1 to 16), further configured according to one of Examples 1 to 57. [Brief explanation of the drawing]

[0076] [Figure 1] A schematic top or side view shows a vacuum chamber apparatus for coating by laser-induced arc evaporation according to various embodiments. [Figure 2A] This paper describes the relationship between temperature and velocity during laser-induced arc evaporation in coatings, and various characteristics related to the resulting properties. [Figure 2B] This paper describes the relationship between temperature and velocity during laser-induced arc evaporation in coatings, and various characteristics related to the resulting properties. [Figure 2C] This paper describes the relationship between temperature and velocity during laser-induced arc evaporation in coatings, and various characteristics related to the resulting properties. [Figure 3] Various pulse shapes of power pulses according to various embodiments are shown. [Figure 4] A schematic top view or side view shows a vacuum chamber apparatus for coating by laser-induced arc evaporation in a continuous system according to various embodiments. [Figure 5A] An exemplary continuous flow system having multiple coating devices for laser-induced arc evaporation according to various embodiments is shown in a schematic top view. [Figure 5B] An exemplary continuous flow system having multiple coating devices for laser-induced arc evaporation according to various embodiments is shown in a schematic top view. [Figure 6] The operation sequences according to various embodiments are shown in schematic diagrams. [Figure 7] The operation sequence is shown using schematic timing diagrams for different embodiments. [Figure 8] The operation sequence is shown using schematic timing diagrams for different embodiments. [Figure 9A] Exemplary power pulses in various embodiments are shown. [Figure 9B] Diagrams illustrating various embodiments are shown. [Modes for carrying out the invention]

[0077] The following detailed description refers with reference to the accompanying drawings, which constitute part of this specification and illustrate specific embodiments in which the invention may be carried out. In this regard, directional terms such as “top,” “bottom,” “front,” “rear,” “forward,” and “backward” are used with reference to the orientation of the figures described. Since the components of the embodiments may be arranged in several different orientations, the directional terms are for illustrative purposes only and not to limit them in any way. It is understood that other embodiments may be used without departing from the scope of the invention and that structural or logical modifications may be made. It is understood that the features of the various exemplary embodiments described herein may be combined with each other unless otherwise specified. Accordingly, the following detailed description should not be construed as restrictive, and the scope of protection of the invention is defined by the appended claims.

[0078] In this specification, the terms “connected,” “joined,” and “coupled” are used to describe both direct and indirect connections (e.g., ohmic connections, and / or conductive connections, e.g., conductive connections), direct or indirect connections, and direct or indirect coupling. In the drawings, identical or similar elements are denoted by the same reference numerals where appropriate.

[0079] In various embodiments, the terms “coupled” or “joined” can be understood to mean a direct or indirect connection and / or interaction (e.g., mechanical, hydrostatic, thermal, and / or electrical). For example, some elements may be coupled together along an interaction chain, e.g., a fluid, in which interactions can be exchanged (in which case it is also called a fluid conduction coupling). For example, two coupled elements may exchange interactions with each other, e.g., mechanical, hydrostatic, thermal, and / or electrical interactions. The coupling of some vacuum components (e.g., valves, pumps, chambers, etc.) may mean that they are fluidly coupled to each other. In various embodiments, “coupled” can be understood to mean a mechanical (e.g., physical) coupling by direct physical contact. The coupling may be configured to transmit mechanical interactions (e.g., force, torque, etc.).

[0080] In relation to vacuum components (e.g., pumps, chambers, lines, valves, etc.), the terms “coupled” or “connected” can be understood as meaning connection to a common vacuum system. Components of a vacuum system may be configured to exchange gases with each other through couplings, thereby separating the couplings from the outside of the vacuum system.

[0081] The actual state of an entity (e.g., a device, system, or process) can be understood as the actual state of the entity or a state that can be detected by a sensor. The target state of an entity can be understood as the desired state, i.e., the specification. Control can be understood as an intentional influence on the current state of an entity (also called the actual state). The current state can be changed according to the specification (also called the target state) by, for example, an operating member, by changing one or more operating parameters of the entity (and therefore also called operating variables). Control may also be understood as steering, where changes in state due to disturbances are further offset. For this purpose, the actual state is compared to the target state, and the entity is influenced, for example, by an operating member, so that the deviation of the actual state from the target state is minimized. In contrast to pure forward-sequence control, adjustment realizes a continuous influence of output variables on input variables, which is brought about by a so-called control loop (also called feedback). In other words, this can be understood as meaning that control can be used as an alternative to or in addition to steering (or control), or that adjustment can be performed as an alternative to or in addition to steering.

[0082] The state of a controllable device (e.g., a structured device) or a controllable process (e.g., structuring) can be specified as a point (also called an operating point or working point) in a space (also called a state space) spanned by the variable parameters (also called operating parameters) of the device or process. Thus, the state of the device or process is a function of the values ​​of one or more operating parameters that represent the state of the device or process. The actual state can be determined based on measurements (e.g., by measuring elements) of one or more operating parameters (also called sensing variables).

[0083] The term "control device" can be understood as any type of logic implementation entity that may have, for example, a circuit and / or processor capable of executing software stored in a storage medium, firmware, or a combination thereof, and issuing instructions thereon. A control device may be configured, for example, by code segments (e.g., software) to control the operation of a system (e.g., its operating point), such as a machine or plant, such as at least its kinematic chain.

[0084] Control can be understood as an intentional influence on a system. The current state of the system (also called the actual state) can be changed according to a specification (also called the target state). The parameters of the target state described herein (also called target parameters) may be implemented, for example, by a code segment, or stored in a storage medium in some other way. Control can also be understood as adjustment, thereby further offsetting changes in the system state due to disturbances. Exemplaryly, a control system may have a forward control path and, therefore exemplary, implement sequence control that translates input variables (e.g., specifications) into output variables. However, the control path may be part of a control loop so that the control system is performed. For control, corresponding operating members of the system that affect the actual state of the system can be controlled. Examples of operating members include drives (e.g., to provide torque), valves (e.g., to control pressure), and switches (e.g., to close a discharge path). Drives may include, for example, a linear drive (e.g., a reciprocating piston) or an electric motor.

[0085] The term “operating member” (including, for example, an actuator) can be understood as a transducer configured to affect a state, process (e.g., a coating process), or apparatus in response to being controlled. An operating member can convert a control signal supplied to it (by which control is performed) into mechanical motion or a change in a physical quantity such as pressure or temperature. An electromechanical (also called electric) operating member may be configured, for example, to convert electric power into mechanical force (e.g., through motion) in response to control. An electric thermal operating member may be configured, for example, to convert electric power into thermal output in response to control. An electric thermal operating member may be configured, for example, to convert electric power into thermal output in response to a control signal. An electrical operating member may be configured, for example, to convert electrical energy (e.g., of a specific voltage, current, and / or power) in response to a control signal.

[0086] An operating member may be configured to influence the actual state (also called the operating point) of a process supplied by the operating member (e.g., its operating variable). The influence may be direct or indirect. The operating variable and the sensing variable may be different from each other, for example. A control variable (e.g., pressure) may be a function of one or more operating variables (e.g., voltage).

[0087] For example, the operating member can change the voltage supplying the arc discharge as an operating variable, resulting in a change in the coating rate or layer thickness as a control variable. For example, the operating member may change the gas flow rate as an operating variable, resulting in a change in the pressure as a control variable. For example, the operating member can change the characteristics of the power pulse (e.g., frequency, total power, pulse shape, pulse duration, etc.), resulting in a change in the coating rate or characteristics of the carbon layer (e.g., layer thickness, conductivity, and / or carbon modification) as a control variable. For example, the operating member may change the frequency at which the excitation pulse (e.g., laser pulse) is generated, resulting in a change in the coating rate or characteristics of the carbon layer.

[0088] Examples of components of the operating member include a power supply (if any), valves (e.g., of a pumping device and / or a gas supply device), motors (e.g., of a valve or pump), and circuits (e.g., for controlling an excitation source (e.g., a laser source)). The power supply may be configured, for example, to generate one or more voltages (and / or their time dependence), one or more currents (and / or their time dependence), and / or power (and / or their time dependence) according to control and supply them to the coating process. The pumping device may be configured, for example, to pump out one or more gases according to control and thus remove them from the coating process. The gas supply device may be configured, for example, to supply one or more gases to the coating process according to control (also called gas supply). The supplied gas may have a gas flow rate (i.e., gas flow per unit time). The gas flow may be, for example, a standard volumetric flow rate supplied to the coating process.

[0089] With regard to the control of operating members, in particular, a more easily understandable operating variable or its operating value that is affected by the operating member is referred to. The above description may similarly apply to control variables or their operating values ​​supplied to the operating member for control, and vice versa. The operating member functions as a converter that translates a control signal into an operating variable or its operating value, and as a result, the operating value is a function of the control value. Modern operating members are provided, for example, as a complex assembly comprising the operating member and a separate control device (also called an operating member control device). The operating member control device may be configured to receive a set value as input via a control signal and to control the operating member according to the set value. The operating variable is then given to the operating member by the generation and transmission of the control variable within the operating member. In simpler operating members, the control variable is simply treated as a control signal, and as a result, the control variable is given to them for control purposes.

[0090] More generally, the operating member may be controlled by a control signal, which may represent an operating variable or its operating value, and / or a control variable or its control value. Alternatively or additionally, the control signal may include instructions specifying how the operating variable or its operating value is changed (e.g., its relative change).

[0091] A “pulse” (e.g., power, also called a power pulse) related to a physical quantity can be understood as a temporal change in a quantity such that its value (e.g., starting from an initial value such as zero) increases, exceeds a maximum value (also called a peak value), and then decreases again (e.g., back to the initial value). The properties of a pulse are a function of the time dependence of the change in the quantity on time. In a pulse, the value of the quantity may change over time from an initial value (e.g., a base value) to a peak value (also called the rising edge of the pulse), and then change over time from the peak value back to the initial value (also called the falling edge of the pulse). Examples of pulse properties include the pulse frequency (specified as frequency), the pulse start time (e.g., defined by a time delay relative to a reference time), the pulse length (also called the pulse duration), the peak value (e.g., amplitude), the pulse shape, and / or the slopes of the rising and / or falling edges. The temporal duration of a pulse (also called pulse duration) is, in some embodiments herein, specified as the readily understandable width of the pulse's time-dependent value curve (e.g., the full width at half maximum or twice the full width at half maximum), although it may be specified differently by analogy. The full width at half maximum corresponds to the temporal width of the signal at half the peak value. In some embodiments, pulse duration is specified as the target duration for which the pulse is generated by a control device (e.g., by controlling an operating member). The pulse shape describes, exemplarily, the geometric shape of a curve whose magnitude is described as a function of time, and the geometric shape may be specified as, for example, a rectangle (and thus also called a rectangular function), a sine, a triangle, etc. For example, if the pulse is described as a rectangular function, then half the width of the rectangular function may be the width of the rectangular function.

[0092] When generating a pulse here, it may be generated according to a target pulse that exemplarily shows the target state of the generated pulse. The target pulse can be specified, for example, as the target time dependence of the generated pulse or as at least its characteristics (e.g., target start time, and / or target time delay, target pulse duration, target frequency, target peak value, target pulse shape, and / or target gradient of the rising edge and / or falling edge).

[0093] A "power pulse" (abbreviated as power pulse) may be understood as a pulse according to time-dependent power and may be generated according to a target power pulse. When the target power pulse defines the time dependence of the current (e.g., current peak value, current gradient, etc.), the power pulse may be implemented, for example, by a current pulse, and accordingly, the power pulse may be controlled and / or adjusted, for example, (e.g., by using it as a reference variable). Alternatively or additionally, when the target power pulse defines the time dependence of the voltage (e.g., voltage peak value, voltage gradient, etc.), the power pulse may be implemented by a voltage pulse, and accordingly, the power pulse may be controlled and / or adjusted, for example, (e.g., by using this as a reference variable).

[0094] An exemplary power pulse (e.g., as a current pulse or a voltage pulse) is shown in FIG. 3. Here, the current or voltage can increase from an initial value to a peak value V max or I max over time t along the rising edge 302 and then return to the initial value along the falling edge 304. The target power pulse can have, for example, a target pulse shape. This may be, for example, a triangle (300a) or a sine wave (300b).

[0095] Arc evaporation, or evaporation by arc discharge, belongs to the classification of thermal evaporation processes, all of which share the common characteristic that the material to be evaporated (hereinafter also simply called the coating material) is heated to transition to a gaseous state (for example, by absorbing latent heat). As a result, melting of the material may occur as an intermediate step (but not necessarily). For example, it may evaporate from the molten material or sublimate directly. Arc discharge is a form of gas discharge in which the formed plasma is contracted into a tube (or, more precisely, a thin thread known as an arc). Inside the plasma tube thus formed, high gas temperatures (e.g., in the range of about 5000 Kelvin to about 50000 Kelvin), current intensity (e.g., in the range of about 2000 amperes or more), and gas pressure are generated, which converts the coating material into a gas phase (also called evaporation). Arc discharge, and therefore plasma formation, can be short in duration, and as a result, it occurs in pulses. Arc evaporation should be distinguished from the cathode sputtering process in which the plasma is generated by a glow discharge (e.g., continuous or pulsed). In cathode sputtering, instead of thermal evaporation, the material is primarily mechanically atomized by large-area ion bombardments from the plasma, thereby the plasma is supplied by a continuous glow discharge (e.g., at a voltage of less than 1000 volts). Pressure is also increased in cathode sputtering.

[0096] An excitation source (e.g., a laser source) is a device configured to generate an excitation pulse, such as an emission pulse, a power pulse (e.g., transmitted as a current pulse or voltage pulse), or the same. An excitation source is generally configured to excite (e.g., trigger) a plasma discharge (e.g., plasma formation and / or charge transfer by plasma) by the excitation pulse. For example, a voltage pulse can be used as the excitation pulse to trigger a plasma discharge. A laser source is a device configured to generate a laser beam. A laser beam is understood to be, for example, the directional (e.g., collinear and / or collimated) propagation of an induced and / or coherent electromagnetic wave. A laser source may, for example, comprise an electromagnetic resonator that performs stimulated emission of the laser beam. In contrast to a continuous-wave laser, a pulsed laser source generates pulsed laser radiation (also called a laser pulse). A laser pulse can be generated by pulse excitation or, for example, by a quality switch of the laser itself. Examples of laser sources include gas lasers (e.g., carbon dioxide lasers) and solid-state lasers (e.g., semiconductor lasers).

[0097] In uncontrolled arc evaporation (also known as arc evaporation), the location of the arc discharge is left to chance. However, depending on the material, this can cause localized "burning" of the cathode, and as a result, the arc discharge is increasingly affected by its own effect. However, this feedback follows interactions that are difficult to control, leading to results that are difficult to reproduce.

[0098] In particular, in carbon arc evaporation (also known as ARC evaporation), lasers have traditionally been used in modifying arc evaporation to control the ignition of the arc discharge, thereby locally inducing plasma formation (also known as laser-induced or laser-assisted arc discharge). In this process, the laser generates a very short pulse of plasma between the anode and cathode in the plasma chamber (to ignite the initial plasma). This initial plasma, lasting from tens of nanoseconds to 100 ns, is then amplified in pulse length and power by arc discharge using a power source (e.g., a pulse power supply and / or a pulse current source). The plasma thus formed reduces the impedance between the cathode and anode, and as a result, the voltage U applied between the cathode and anode is reduced. arc The arc voltage (also called the pulsed arc discharge) generates a discharge current through the plasma. In other words, pulsed arc discharges can be excited by a laser.

[0099] First, various embodiments will be described below according to different models.

[0100] The time course (also called the pulsed current curve) of the current pulse of such an arc discharge (also called a cathode discharge) at this ignition point is, for example, the pulse shape of the current pulse (e.g., triangle, rectangle, semisine, etc.) and the amplitude I K and / or pulse length t p This can be adjusted by a pulsed current source.

[0101] The laser is guided onto the cathode by a mirror system, allowing for specific modification of the arc discharge position. The laser influences the ignition position on the cathode, thus ensuring uniform, non-contact ablation of the target material.

[0102] For example, the frequency of position changes and / or the pulse frequency of the current pulse can be set using the laser clock frequency f.

[0103] These parameters, for example, are related to the so-called source power P according to the following relationship: Q It can be converted to [this].

number

[0104] Source power serves as a measure of the power converted by the arc discharge to which the substrate is exposed. Source power P is thus determined. Q This is the coating speed Rnm / min (nanometers / min).

[0105] According to various embodiments, the arc generated by the laser-induced arc discharge has a relatively high coating speed R(P Q This enables (i.e., the amount of material evaporated per unit time). In a continuous flow system, the coating rate (the rate at which the substrate is coated as it is being transported) and / or the thickness of the layer are often normalized with respect to the transport rate v of the substrate, and are called, for example, the dynamic deposition rate (e.g., nm m / min).

[0106] In continuous systems, the rate at which the transported substrate is coated (also called the coating rate) is often specified as the dynamic deposition rate (e.g., nm m / min), which is a function of the product of the thickness of the layer produced by the coating and the transport rate at which the substrate is transported, providing a more equitable value of the deposition rate for different scenarios.

[0107] The dynamic coating speed is the speed R(P Q In this case, for example, DDR represents the length l coated onto the substrate every time t (e.g., in minutes), and l can be expressed, for example, according to the following relationship: I = vt (e.g., in minutes). Therefore, DDR is a function of the transport speed v as the substrate is transported through the coating source.

[0108] In a continuous flow system (for example, in-line), the substrate (such as a bipolar plate) may be transported by a transport device along a transport path, passing through the cathode of the coating source, resulting in the material evaporated by the arc discharge (also called material flow) colliding with the substrate, and thus forming a material layer, such as a carbon layer, (according to one or more specifications, such as a target layer thickness).

[0109] Examples of parameters for which specifications exist include layer thickness (also called target layer thickness), coating properties (also called target layer properties), and / or throughput (also called productivity), where throughput can be expressed, for example, as the length of substrate coated per unit time and / or in relation to the entire system (in which case also called plant throughput).

[0110] This is because the layer thickness is a function of the coating speed and the transport speed, and therefore a function of the source power.

[0111] Coating a substrate (also known as depositing layers onto a substrate) according to one or more specifications (e.g., target layer thickness and / or target transport speed) can be performed using source power as an operational variable. For example, as a first approximation, if the target layer thickness is constant, the source power is proportional to the target transport speed, thereby allowing for scaling of plant throughput. However, the energy input to the substrate (e.g., normalized with respect to the substrate area) is a function of the target layer thickness and therefore a function of the dynamic velocity DDR.

[0112] In various embodiments, it is addressed that the substrate is heated by the energy input of the coating plasma, and its temperature can rise relatively rapidly. The properties of some substrates (e.g., their materials and / or coatings) may degrade when the critical material temperature is exceeded (at least). The analysis of the colorimetric properties of the substrates (e.g., substrate materials) described below as an example provides insight into this context, particularly for evaluating the feasibility of coating processes using laser-induced arc evaporation on an industrial scale.

[0113] For example, the heat capacity C of a substrate, such as stainless steel foil (e.g., used in the manufacture of bipolar plates), decreases as the substrate thins, and can range from 1 to 10 mJ / K (millijoules / Kelvin) normalized to 1 square centimeter (also called surface heat capacity) of the substrate exposed to plasma (e.g., in millijoules per square centimeter and per Kelvin). A thickness t made of a material (such as stainless steel or titanium) with density ρ and specific heat capacity c... D The surface heat capacity of a metal foil is given by C = cρt D It is expressed as follows: Energy input E of the coating source (e.g., J / cm²). 2 This raises the substrate temperature by ΔT = E / C. At the same time, the substrate can release some of the heat (e.g., through radiation or thermal conduction), which suppresses the temperature rise of the substrate. However, in a vacuum, this contribution is so small that it can be ignored as a first approximation in the coating dynamics, at least on short time scales of energy input.

[0114] In industrial plants, the process of extracting thermal energy from substrates can be difficult to implement (compared to, for example, laboratory plants). Furthermore, industrial plants often have higher requirements regarding robustness to disturbance variables (compared to, for example, laboratory plants).

[0115] In this context, one example of this is recognized as a carbon layer that can be formed on a substrate (e.g., a bipolar plate). Such carbon layers may be subject to high requirements regarding properties (also called layer properties), such as surface contact resistance, corrosion resistance, and adhesion, in order to ensure high quality.

[0116] These characteristics (e.g., quality) are related to the voltage applied to the substrate (substrate bias voltage (U B It can also be affected by the substrate bias voltage (U), which accelerates ions in the plasma in addition to their initial energy. High-energy ions can affect, for example, the layer morphology, but also increase the energy input to the substrate. Depending on the plasma transmittance in the coating chamber, a portion η of the arc current integral generated on the cathode is supplied to the substrate as an ion current with a time delay related to the time of flight. B The additional power input P that arises as a function of ) B The bias power (also called bias power) can be expressed by the following first approximation:

number

[0117] If a minimum energy level exists for high-energy ions to promote the formation of the target layer morphology, this can result in a lower limit for the substrate bias voltage, for example, in the range of 800V or higher.

[0118] Therefore, the energy input to the substrate being transported through the plasma at the actual transport speed (for example, an invariant one) is from two power sources (P Q and P B These can be understood as functions of the operating point of the plasma source and the substrate. This relationship is shown in Figure 900b (see Figure 9B), where the energy density 911 input to the substrate is plotted schematically against the bias power 913 and the source power 915 (au).

[0119] The specification specifies that the maximum temperature T that the substrate must not exceed during coating is specified. max Based on this, the maximum energy input E introduced into the substrate during coating. max This can be determined as a specification, for example, according to the following relation: E max =(T max (-T0). Optionally, upstream processes to which the substrate is exposed and which affect the substrate's starting temperature T0 can also be taken into consideration.

[0120] In exemplary embodiments, the maximum temperature (as the critical material temperature) can be around 600°C, and beyond this point (e.g., formed by laser-induced arc evaporation), growth tends to deviate more strongly from the target (e.g., substantially amorphous carbon transformation or substantially crystalline carbon transformation without crystallographic texture), and therefore no longer meets the property requirements.

[0121] In various embodiments, it is recognized that, in addition to the parameters described above, there are additional operational variables (see embodiments) that can be used to influence (e.g., reduce) the energy input to the substrate (and the resulting power input), while simultaneously enabling the formation of a high-quality carbon layer. This is based, in particular, on the understanding that only a subset of high-energy ions are sufficient to promote the formation of the desired layer properties.

[0122] In exemplary embodiments, the source of the substrate bias voltage (also called a bias pulse current source) is provided (e.g., controlled) so that only a portion of the ionization plasma is post-accelerated by the substrate bias voltage, thereby reducing the energy input to the substrate. For this purpose, pulse overlapping and / or pulse omission are implemented according to various embodiments. For example, the period during which the substrate bias voltage is applied to the substrate may be provided such that only a percentage PO(%) of the substrate power pulse is effective. For example, it is recognized that the value of PO can be reduced to 25% without significantly affecting the layer characteristics.

[0123] In an exemplary embodiment, an operating point (AP, e.g., AP1, AP2, AP3, AP4 are shown) can be determined as follows (see FIG. 9). According to one or more specifications, for example, based on specifications of layer thickness and / or system throughput, a target coating rate R (also called target speed) R = R1 can be determined. In the example of material A, R = R1 results in an energy input at operating point AP1 that exceeds the maximum energy input as threshold 917 (black line). Based on this, the target speed can be reduced to R = R2 < R1 (see Var. 1), sacrificing layer thickness and reducing the possible operating point AP2. In the case of forming a carbon layer, the critical material temperature as threshold 917 can limit the dynamic coating rate (e.g., per cathode) to less than, for example, 50 nm m / min. When the conveyance speed is constant, the range for selecting an operating point (also called selection range) increases with the operating variable of bias power 913. Conventionally, the bias power has always been specified due to existing boundary conditions. In contrast, according to various embodiments, the bias power 913 can be used as an operating variable that can be changed instead of or in addition to the operating variables of source power and conveyance speed.

[0124] Alternatively or additionally, various embodiments enable reducing the energy input to operating point AP3 by pulse repetition and / or pulse omission without necessarily changing the target speed (see Var. 2). For example, in the case of a more thermally sensitive material B, the target speed is R = R2 < R1 (which results in a lower layer thickness), and pulse repetition and / or pulse omission can be changed to facilitate coating of the substrate at operating point AP4 according to the coating quality requirements. For example, if R2 represents a value at which a minimum layer thickness is generated on the substrate, an AP (see AP4) that was previously inaccessible is opened for material B.

[0125] FIG. 1 shows a vacuum chamber apparatus 100 for coating by laser-induced arc evaporation according to various embodiments in a schematic top view (or schematic side view). The pulse signal is indicated by "^".

[0126] The vacuum apparatus 100 may include a vacuum chamber 102. The vacuum chamber 102 may be provided, for example, by a chamber housing that can house one or more vacuum chambers. The chamber housing may be coupled, for example, to a pumping device for providing negative pressure or vacuum, such as a vacuum pumping device (vacuum chamber housing), and may be configured to be stable so as to withstand the effects of pneumatic pressure in a pump-down state. The pumping device (including at least one vacuum pump, such as a high vacuum pump, such as a turbomolecular pump) can enable pumping out a portion of the gas from inside the vacuum chamber 102. The vacuum chamber 102 may optionally have a chamber cover that vacuum-seals the inside of the vacuum chamber 102. Thus, the plasma of the arc discharge may have negative pressure (e.g., vacuum).

[0127] The chamber housing, for example, the vacuum chamber 102 provided therein, is at a negative pressure (i.e., a pressure below atmospheric pressure), for example, a vacuum (i.e., a pressure below 0.3 bar), for example, a pressure in the range of about 10 mbar to about 1 mbar (in other words, a crude vacuum), for example, about 1 mbar to about 10 -3 Below a pressure in the range of mbar (in other words, a very low vacuum), for example, about 10 -3 mbar -7 Below the pressure range of mbar (in other words, below high vacuum), for example, below high vacuum, for example, about 10 -7 It may be configured so that a pressure of less than mbar can be supplied within it. Atmospheric pressure (e.g., 1 bar) may be the pressure acting on the chamber housing from the outside.

[0128] The vacuum assembly 100 may include a coating apparatus 108. The coating apparatus 108 may be configured to coat using a laser-induced arc discharge.

[0129] The gas pressure used to operate the coating apparatus 108 (also called the operating pressure), and / or the gas or gas mixture supplied to the coating apparatus 108 (also called the operating gas), can be highly application-dependent. For example, the operating pressure may be approximately 10 -4 From mbar (millibar) to approximately 5 x 10 -4 The range may be in the mbar range. For example, the working gas may include one or more of the following gases: oxygen (e.g., molecular oxygen, i.e., O2), nitrogen (e.g., molecular nitrogen, i.e., N2), hydrogen (e.g., molecular hydrogen, i.e., H2), one or more hydrocarbon compounds, or a mixture thereof. The working gas may include a working gas (e.g., an inert gas) and / or a reactive gas. The reactive gas may include, for example, hydrogen.

[0130] The coating apparatus 108 may include a target holder (not shown) for holding the target 112. The target holder may provide a pivot axis and be configured to rotate the target 112 (if held in the target holder) around the pivot axis.

[0131] The coating apparatus 108 may include a laser source 110. The laser source 110 may be configured to generate laser pulses 114 (i.e., pulsed laser beams) toward a target holder (for example, toward a target 112 held in the target holder).

[0132] During the operation of the vacuum assembly 100, the target 112 may be held within a target holder. The laser source 110 may be configured to generate a laser pulse 114 directed at the target 112. This laser pulse 114 can excite (e.g., induce) an arc discharge in the target 112. In this case, the target 112 can be made to act as a cathode. Therefore, the target holder may also be called a cathode end block.

[0133] A cathode end block (hereinafter also referred to as an end block for simplicity) can be defined as a device configured to hold a cathode and supply, for example, torque, electrical energy, and optionally a cooling fluid to the cathode for rotation. To provide torque, the end block may have a drive device (e.g., a motor), or at least be coupled to such a device. The end block may be mounted inside a vacuum chamber, for example, in a through-hole in the chamber wall (also called a supply opening). Electrical energy and / or cooling fluid (and optionally torque) may be supplied to the end block through the supply opening. Optionally, one or more additional media may be supplied to the end block, which serve to supply data to the cathode, for example, for controlling and / or reading a sensor.

[0134] The target 112 generally has, or may be composed of, a coating material that is converted into a gaseous state.

[0135] The target 112 may generally be tubular (a so-called tubular cathode). The target 112 may have, for example, a tubular carrier (a so-called carrier tube) to which a coating material (e.g., brittle and / or fragile) can be attached. For example, the target 112 may have a transport tube for transporting the coating material. For clarity, the coating material may surround the target base tube in the form of a jacket. Alternatively, the target 112 may have, or be formed from, a tubular coating material (a so-called target tube) (e.g., a tube made of the coating material). The diameter of the tubular target may range, for example, from about 10 cm to about 50 cm, for example, about 20 cm or more.

[0136] The vacuum assembly 100 may include a power supply 118 (also called a power supply unit). The power supply 118 may be configured to provide, for example, a pulsed operating voltage (e.g., a DC voltage). For this purpose, the power supply 118 may include, for example, a pulsed current source, or be formed from a pulsed current source.

[0137] The operating voltage may be applied between the anode and the target holder. The applied operating voltage may be set so that current can discharge between the anode and cathode, but spontaneous ignition (the initiation of an uncontrolled discharge) does not occur. For this purpose, the operating voltage may be lower than the ignition voltage (i.e., the voltage at which the arc discharge is ignited) and higher than the combustion voltage (i.e., the voltage at which the arc discharge occurs). For example, the anode potential at the anode may be in the range of about 10 to about 20 V. The cathode potential at the cathode may be negative, for example (e.g., relative to electrical ground), and / or its magnitude may be in the range of about 240 V to about 350 V.

[0138] The power supply 118 may be configured to generate a first power pulse 120. The first power pulse 120 may be applied to the target 112. The first power pulse 120 may be configured to electrically supply an arc discharge (induced by the laser pulse 114) (e.g., by the target 112). For this purpose, the target holder may be electrically coupled to the power supply 118.

[0139] The vacuum apparatus 100 may include a control device 124. The control device 124 may be configured to control the laser source 110. For example, the control device 124 may control the laser source 110 to generate a laser pulse 114, thereby initiating a laser-induced arc discharge. The control device 124 may be configured to control a power supply 118. For example, the control device 124 may control the power supply 118 to generate a first power pulse 120. In this case, the control device 124 may control the power supply 118 to generate the first power pulse 120 according to a (first) target power pulse (e.g., a target current pulse). The first power pulse 120 may be transmitted by a current pulse generated (or controlled) by the power supply 118.

[0140] The power supply 118 may have an output filter configured to be controlled in response to a target power pulse in order to influence the time dependence of the power pulse.

[0141] The (first) target power pulse (e.g., target current pulse) can define the time dependence of the power (e.g., current). According to various embodiments, the (first) target power pulse is approximately 10 × 10 6 A / s to approximately 24 x 10 6 The target current pulse may also be a time-dependent target current pulse with a gradient in the range of A / s (see, for example, the rising edge 302 and falling edge 304 shown in Figure 3).

[0142] Consecutive pulses may be generated, for example, according to a target frequency, with a time offset between them. This frequency is also called the pulse frequency. The target pulse frequency of the (first) target power pulse may be, for example, as described in Example 9.

[0143] Where a target parameter (e.g., a target power pulse, a target time delay, and / or a target frequency) is referred to herein, it may be implemented by a code segment that can be stored in a data memory associated with the control device 124. The code segment may be stored in the data storage device in an appropriate manner, for example, as a list (e.g., a table), a set of values, an algorithm, etc. The data storage device (also commonly called a storage medium) may be, for example, a non-temporary data storage device. The data storage device may include, for example, a hard disk and / or at least one semiconductor memory (read-only memory, direct-access memory, and / or flash memory, etc.), or may be formed from them. The read-only memory may be, for example, an erasable programmable read-only memory (also called an EPROM). The random-access memory may be a non-volatile random-access memory (also called an NVRAM).

[0144] Control by the control device 124 may be performed according to an operation sequence. This operation sequence may be stored in data memory in an appropriate manner, for example, as an algorithm, or by code segments in another manner.

[0145] The target holder may be configured to induce rotational motion of the target 112 around a rotation axis. For example, the target holder may have a drive device (e.g., an electric motor) configured to apply torque to the target for this purpose. The control device 124 may be configured to control the drive of the target holder in order to control the rotational motion (e.g., rotation frequency). The rotation frequency may be, for example, as defined in Example 25.

[0146] An electric arc can convert a target material (e.g., a solid) at least partially (e.g., at the discharge point on target 112) into an aggregate of gaseous material (also simply called a gaseous state or vapor). This conversion may also be simply called evaporation, but may generally include sublimation (i.e., a direct transition of the target material from a solid state to a gaseous state). The material released from target 112 by the arc discharge (e.g., evaporated from target 112) may form a material flow 116 away from target 112.

[0147] During the operation of the vacuum assembly 100, one (or more) substrates 106 may be coated by the material flow 116. For this purpose, the vacuum assembly 100 may have a substrate holder 104 configured to hold one or more substrates. The substrate holder 104 may be located inside the vacuum chamber 102. In various embodiments, the distance between the rotation axis and the substrate holder may be in the range of about 410 mm to about 750 mm.

[0148] The substrate or each substrate may generally include a workpiece, such as a semi-finished product (e.g., a rod, sleeve, or plate), or a component of a more complex device. Examples of substrates include piston rings, bearing components, tools, chains, drive chains, obtuse angles, knives, or components sensitive to sliding friction. The substrate or each substrate may be, for example, cylindrical, plate-shaped, or have other shapes.

[0149] The substrate, or each substrate, comprises or may be formed from at least one of the following: ceramic, glass, semiconductor (e.g., amorphous, polycrystalline, or monocrystalline semiconductors such as silicon), metal, and / or polymer (e.g., plastic). The ceramic may include, for example, metal oxides, nitrides, and / or carbides.

[0150] Within the scope of this specification, a metal (also called a metallic material) may comprise (or be formed from) at least one metallic element (i.e., one or more metallic elements), for example, at least one element from the following group of elements: copper (Cu), iron (Fe), titanium (Ti), nickel (Ni), silver (Ag), chromium (Cr), platinum (Pt), gold (Au), magnesium (Mg), aluminum (Al), zirconium (Zr), tantalum (Ta), molybdenum (Mo), tungsten (W), vanadium (V), barium (Ba), hafnium (Hf), samarium (Sm), silver (Ag), and / or lithium (Li). For example, a metal may comprise (or be formed from) a metallic compound (e.g., an intermetallic compound or alloy), or a compound of at least one metallic element (e.g., from the group of elements) and at least one nonmetallic element (e.g., carbon), for example, steel.

[0151] In a clear example, the substrate 104 may be a bipolar plate (e.g., a metal), and the target 112 may contain or consist of carbon, and as a result, a carbon layer may be formed on the bipolar plate by a material flow 116 generated by a laser-induced arc discharge. The carbon layer may contain or be formed from, for example, tetrahedral amorphous carbon in which hydrogen is optionally stored. However, the carbon may exist in other carbon transformations.

[0152] The carbon in the carbon layer may exist in one of the following carbon transformations, for example: graphite; amorphous carbon; tetrahedral carbon; diamond-like carbon; fullerene; diamond; carbon nanotube; amorphous tetrahedral carbon; and / or nanocrystalline carbon, e.g., nanocrystalline graphite. Optionally, hydrogen can be incorporated into the carbon (i.e., hydrogen-doped carbon configuration).

[0153] In various embodiments, the power supply 118 may be configured to generate a second power pulse 122. The second power pulse 122 may be configured to accelerate a material flow 116 (e.g., the ionized portion of the material flow) away from the target 112 toward the substrate holder 104. For this purpose, the substrate holder 104 may be electrically coupled to the power supply 118. The second power pulse 122 can increase the kinetic energy of the material in the material flow 116 as it collides with the substrate 106. This can result in, for example, the formation of a more compact layer. In some applications, this second power pulse 122 can even facilitate the achievement of desired properties (e.g., minimum surface contact resistance or minimum corrosion resistance in the case of a carbon-coated bipolar plate). The control device 124 may control the power supply 118 to generate the second power pulse 122 according to a second target power pulse (e.g., a target voltage pulse). The second power pulse 122 may be transmitted by a voltage pulse generated (or controlled) by the power supply 118.

[0154] The maximum pulse current of the arc discharge may be limited to, or become limited to, a maximum pulse current in the range of, for example, about 1000A to about 5000A, preferably in the range of about 1600A to about 3000A, and more preferably in the range of about 2000A to about 2500A (by, for example, by the operating sequence).

[0155] In various embodiments, the laser pulse 114, the first power pulse 120, and optionally the second power pulse 122 can also be coordinated, i.e., synchronized (e.g., by an operating sequence) so that they overlap in time. For this purpose, the control device 124 may have, for example, a clock generator, thereby synchronizing the laser pulse 114, the first power pulse 120, and optionally the second power pulse 122 with each other. Each clock pulse of the clock generator can define a reference time, e.g., exactly one reference time for each phase, and / or a reference time at which the phase begins. For clarity, the reference time may be the start of a transfer. Optionally, there may be time offsets (e.g., in the μs range) between the laser pulse 114 and the first power pulse 120, and / or between the laser pulse 114 and the first power pulse 120, and / or between the first power pulse 120 and the second power pulse 122, etc. A time offset (e.g., in the μs range) may exist, which may take into account, for example, the time between the generation of the laser pulse 114 and its effect on the target 112, and / or the time between the generation of the material flow 116 and its effect on the substrate 106. For example, a second power pulse 122 (if generated in a clock cycle and / or phase) may be generated at a (second) target time difference (also called a target time delay) from a reference time (e.g., the start of each phase). Exemplary, the second power pulse 122 may start later than the first power pulse 120 (if the first power pulse 120 is generated without a target time delay, or with a smaller target time delay than the second power pulse 122).

[0156] In various embodiments, the substrate 106 can be coated by repeatedly generating arc discharges (according to a target frequency) having associated material flows 116. Here, repeated means of repeatedly exciting the arc discharge with one or more pulses, for example, a laser pulse 114 and a first power pulse 120. With each repeated, a laser pulse 114, a first power pulse 120, and optionally a second power pulse 122 may be generated.

[0157] For example, the operating sequence may have one or more phases of a first type in which a laser pulse 114, a first power pulse 120, and a second power pulse 122 are generated in each iteration. For example, the operating sequence may have one or more phases of a second type (e.g., including a duration twice that of the first phase) in which two (or more) iterations are performed, in which the laser pulse 114 and the first power pulse 120 are generated in each iteration, but the second power pulse 122 is generated in only one of the two (or more) iterations. For example, the operating sequence may include at least one phase in which the laser pulse 114, the first power pulse 120, and the second power pulse 122 are generated, and the first power pulse 120 and the second power pulse 122 overlap only partially (in time).

[0158] Although a single power supply 118 is described herein, it is understood that the vacuum assembly 100 may also include multiple power supplies, each of which may generate a power pulse as described herein, for example, a first power supply may generate a first power pulse, a second power supply may generate a second power pulse, and so on.

[0159] Optionally, the vacuum assembly 100 may include a particle filter positioned between the target holder and the substrate holder 104 and configured to filter the material flow 116 discharged from the target 112 by the arc discharge. Filtering the material flow may be understood as separating the material flow into a first portion and a second portion, the first portion being supplied to the substrate 106 and the second portion not being supplied. For example, the second portion of the material flow may be collected before reaching the substrate 106.

[0160] Figures 2A and 2C show, schematically, different characteristics of coatings produced by laser-induced arc evaporation, relating to the relationship between temperature and velocity, and their respective effects on the surface contact resistance (ICR) of the generated layer.

[0161] The term "surface contact resistance" refers to the surface's contribution to the system's total resistance, which, in contrast to intrinsic resistance, can be due to the contact area between the conductor and the connection.

[0162] Surface contact resistance is an exemplary material property and is used here for illustrative purposes only. Therefore, it is understood that the principles described herein may be similarly applicable to other properties.

[0163] As shown by the velocity-temperature curve 204 in Figure 200a of Figure 2A, a higher (e.g., dynamic) coating rate R results in a higher material temperature of the layer due to the energy input to the formed layer. Figures 200b and 200c show that the surface contact resistance ICR can increase with increasing temperature or rate.

[0164] For example, target contact resistance ICR * If a layer with the following surface contact resistance is produced, this means that the temperature the material can reach during coating is the critical temperature T. c The coating speed is limited to the critical coating speed R, since temperature depends on the coating speed. c It is limited to the critical temperature T. c This can be accompanied by a critical change in the properties of the layers (for example, due to delamination between layers).

[0165] The second power pulse 122 described herein (for example, as a voltage pulse, also called a bias voltage pulse) is used to make the surface contact resistance the target contact resistance ICR * (and / or other desired properties such as desired corrosion resistance) can be achieved or reduced. For example, in the case of carbon coatings, the use of a second power pulse 122 can result in a carbon stalk structure, or at least promote its formation, which is the target contact resistance ICR. * , and / or properties such as corrosion resistance can be improved. For example, as the peak value of the second power pulse 122 increases, the sp of the carbon bond 2The hybridized portion may increase. For example, stem-like structures may be formed starting at a peak value of approximately 700 V. In this case, the stem diameter may be 50 nm or less, preferably 25 nm or less.

[0166] Figures 200a, 200b, and 200c shown in Figure 2A illustrate the respective progressions when a second power pulse 122 is generated with each arc discharge (i.e., in each iteration).

[0167] If this second power pulse 122 is omitted in some iterations that generate the arc discharge, the layer temperature T can be reduced without significantly affecting the contact resistance, and as a result, for example, the target contact resistance ICR * It is still recognized that undershoot can occur simultaneously. In this case, a phase may occur in which multiple arc discharges are excited with each second power pulse 122.

[0168] Figure 202a in Figure 2B shows a schematic velocity-temperature curve 206 when the second power pulse 122 is omitted in some iterations. Figures 202a, 202b, and 202c show the R for velocity-temperature curve 204 at the same critical temperature Tc. c1 The critical velocity is R in the case of velocity-temperature curve 206. c2 This indicates an increase in the rate of application. As a result, this enables the use of higher (e.g., dynamic) coating speeds. According to various embodiments, by omitting the second power pulse 122 every 10 iterations, dynamic coating speeds of 50 nm / min or 1 cm / min or more are already possible. By omitting the second power pulse 122 every 5 iterations, dynamic coating speeds of 300 nm / min or more can be achieved, for example, when coating a bipolar plate with carbon.

[0169] The control device 124 may be configured to implement the omission of the second power pulse 122, for example, by an operating sequence. For this purpose, the control device 124 may have, for example, a counter that counts the generation of the first and / or second power pulses and / or laser pulses. However, omitting too many second power pulses 122 may result in certain target characteristics no longer being achieved. Therefore, the omission of the second power pulse 122 may be limited to a maximum of every n iterations, where n is any natural number greater than or equal to 2 (e.g., 3 or more, e.g., 4 or more, e.g., 5 or more). This may depend on the desired characteristics, materials, etc., of the layer being manufactured. For example, when coating a bipolar plate with carbon, the omission of the second power pulse 122 may be limited to a maximum of every 5 iterations, resulting in the target contact resistance ICR * This is still achieved. For example, an operation sequence may have one phase of the second type for every several (e.g., two, three, or four) phases of the first type.

[0170] The coating process may have several phases, each of which may have one or more iterations that generate an arc discharge. If the second power pulse 122 is not omitted in one or more iterations of the first phase, then in this first phase, exactly one first power pulse 120 and exactly one second power pulse 122 are generated for each laser pulse. If the second power pulse 122 is omitted in one of the two iterations of the second phase, then in these two iterations of the second phase, two laser pulses 114 and two first power pulses 120 are generated for each second power pulse 122.

[0171] An exemplary operation sequence 600 relating to this point is shown in Figure 6.

[0172] It is also recognized that if the second power pulse 122 and the first power pulse 120 only partially overlap in time (when they are generated in one phase and / or one clock cycle), the layer temperature T can be additionally or alternatively reduced. This temporal overlap is also called pulse coverage. When the first and second pulses start simultaneously (e.g., at the reference time of the clock cycle) and the first and second pulses end simultaneously (e.g., because they have the same target pulse duration), there is full temporal overlap. In this case, the pulse overlap is equal to 1 (i.e., 100%). When one pulse starts after another pulse (e.g., due to a target time delay relative to the clock reference time), and / or when one pulse ends before another pulse (e.g., due to different target pulse durations), these pulses only partially overlap. In this case, the pulse coverage is less than 1 (i.e., less than 100%).

[0173] To clarify, the layer temperature T can be reduced, either additionally or alternatively, by reducing pulse overlap.

[0174] Figure 7 shows an exemplary operation sequence 700 with schematic timing diagrams of the first power pulse 120 and the second power pulse 122, illustrating the generation of power pulses over time t.

[0175] The operation sequence 700 may have several phases 701. In each phase 701, a first power pulse 120 and a second power pulse 122 may be generated.

[0176] Each power pulse may be generated (for example, according to a target time delay and a target pulse duration) such that it includes a start time t0 and an end time t1, with the interval between them specified as the pulse duration.

[0177] In various embodiments, a first power pulse 120 (for example, according to a first target time delay and a first target pulse duration) and a second power pulse 122 (for example, according to a second target time delay and a second target pulse duration) may be generated in phase 701 such that they overlap each other only partially.

[0178] As described herein, they are, for example, different starting times t0 (i.e., t 0,120 ≠t 0,122 ) starts at and / or a different end time t1 (i.e., t 1,120 ≠t 1,122 If it ends at ), it only partially overlaps. In this case, the pulse overlap is less than 1. The pulse overlap duration is equal to the overlap start time t. 0,pulse overlap And, overlapping end time t 1,pulse overlap It could be a period between those two dates.

number

number

[0179] As described herein, the reference point of a phase may be the start of the phase. The target time delay described herein may, exemplarily, be the target time difference from the reference point of the phase (e.g., the start of the phase).

[0180] In the example operation sequence 700 shown in Figure 7, the first power pulse 120 in each phase 701 is generated at a reference time of the clock generator (i.e., according to a first target time delay = 0), and the second power pulse 122 in each phase 701 is generated according to a (second) target time delay after the reference time of the clock generator (i.e., according to a second target time delay > 0). Furthermore, in this exemplary operation sequence 700, the first power pulse 120 is generated according to a first target pulse duration, and the second power pulse 122 is generated according to a second target pulse duration that is smaller than the first target pulse duration (and smaller than the difference between the first target pulse duration and the second target time delay, such that the second power pulse 122 terminates before the first power pulse 120). Thus, the second target time delay may be larger than the first target time delay, and the second target pulse duration (= t 1,122 -t 0,122 ) is the first target pulse duration (=t 1,120 -t 0,120 It can be smaller than ).

[0181] In various embodiments, the critical coating rate can be significantly increased by combining the omission of individual second power pulses 122 with the reduction of pulse overlap between the first power pulse 120 and the second power pulse 122. In this case, the increase in the approximate rate-temperature curve 206 (see Figure 2B) is significantly reduced, and as a result, the critical temperature T c This is due to an extremely high critical velocity R c2 It is reached by [this method].

[0182] Figure 8 shows an exemplary operating sequence 800 having a schematic time diagram of a first power pulse 120 and a second power pulse 122, where the first power pulse 120 and the second power pulse 122 are generated in phase 701, and the first power pulse 120 is generated, but the second power pulse 122 is not generated in phase 801 (i.e., omitted).

[0183] When a power pulse is measured, the start time t0 and end time t1 of the power pulse can be determined, for example, based on a threshold. Figure 9 shows the peak voltage value V. max and the peak value of the current I max The voltage and current time curves of an exemplary power pulse 900a having a threshold (V) are shown. th or I th ) is the peak value V max or I max It may be a predetermined percentage (for example, 10% or less, for example, 5% or less). In this case, the pulse width is the time difference between two points in time t0 and t1 where the time curve reaches a threshold.

[0184] The target pulse length of the power pulse (for example, the first) may generally be in the range of about 30 μs to about 600 μs. In this regard, it is recognized that when this target pulse length l(p) (and therefore essentially the pulse length of the first power pulse 120) is in the range of about 250 μs to about 350 μs, the surface contact resistance ICR of the formed layer (for example, in the case of a carbon layer) is reduced. This is schematically shown in Figure 208a of Figure 2C. Using a target pulse length of the first power pulse 120 in the range of about 250 μs to about 350 μs can result in the formation of both monovalent and divalent carbon ions in the case of carbon arc evaporation. In this regard, it is recognized that this can promote layer formation and thus result in a reduction of the surface contact resistance ICR. Since the pulse length depends on the slope of the rising and falling edges of the pulse, it is understood that the target slope can also represent the target pulse length.

[0185] In Figure 208b, curve 210 points to the layer produced using a target pulse length of the first power pulse 120 in the range of approximately 250 μs to approximately 350 μs. The decrease in surface contact resistance ICR is due to a higher critical temperature T c2 Target contact resistance ICR that can only be reached (or exceeded) * This is illustrated by example. Therefore, in this case as well, the coating rate (e.g., dynamic) can be increased with little risk of damage to the carbon layer.

[0186] Depending on the configuration, omitting individual second power pulses 122 and / or reducing pulse overlap may be combined with selecting a target pulse length for the first power pulse 120 from a range of about 250 μs to about 350 μs in order to further increase the critical coating speed.

[0187] Generally, the coating speed can be increased by increasing the pulse frequency and / or pulse length of the first power pulse 120. If the pulse length of the first power pulse 120 is selected from the above range, the coating speed can be increased by increasing the pulse frequency of the first power pulse 120.

[0188] In various embodiments, omitting individual second power pulses 122 and / or selecting a target pulse length for the first power pulse 120 from a range of about 250 μs to about 350 μs can facilitate the formation of a carbon layer on a substrate that includes one or more of the characteristics specified in Examples 38 to 47.

[0189] As described herein, laser-induced arc evaporation can be used to coat substrates in a continuous flow system. Figure 4 shows an exemplary vacuum chamber assembly 400 for coating by laser-induced arc evaporation in a continuous flow system according to various embodiments in a schematic top view or schematic side view. The vacuum chamber assembly 400 may include a transport device 402. The transport device 402 may be configured to transport the substrate 106 along a transport path (e.g., in the transport direction 101) through the coating device 108. Optionally, the vacuum chamber assembly 400 may include a cooling element 404 (e.g., a cooling plate) for cooling the substrate 106. Cooling the substrate 106 with the cooling element is, for example, to achieve a critical coating rate R c This could be increased even further.

[0190] In this case, the transport device 402 and the vacuum device 100 may be controlled so that the coating rate at which a layer (for example, a carbon layer on a bipolar plate) is formed on the substrate 106 is 50 nm m / min or more.

[0191] Figures 5A and 5B show schematic top views of exemplary continuous flow systems 500 having multiple coating devices 108 according to various embodiments.

[0192] As shown in Figure 5A, in the continuous flow system 500, at least one substrate 106 can pass through a plurality of coating devices 108(k,m) and then be transported by the transport device 402. The coating devices 108(k,m) can be located on both sides of the transport path (for example, on the left side when k=1 and on the right side when k=2 with respect to the transport direction 101). For example, M coating devices 108 may be located on each side of the transport path, where M is any integer greater than or equal to 1. Thus, the coating devices 108(k,m) can be specified by integers k and m (1≦m≦M).

[0193] For example, at least one substrate 106 may be configured in a carrier that can be transported along a transport path by a transport device 402. In some embodiments, the second power pulse 122 described herein may be applied to this carrier.

[0194] According to various embodiments, one of the multiple coating apparatuses 108(k * ,m * ) may have a first (e.g., dynamic) coating speed, and another coating apparatus 108(k) among the plurality of coating apparatuses. * ,m / m *The coating apparatus may have a second coating rate different from the first coating rate. For example, the first carbon layer may be formed on the substrate 106 using the first coating apparatus 108(1,1) at a coating rate of less than 50 nm m / min, and then the second carbon layer may be formed on the first carbon layer using the second coating apparatus 108(1,2) at a coating rate of 50 nm m / min or more, and then used to form the second carbon layer on the first carbon layer at a coating rate of 50 nm m / min or more. For example, in this case, the first carbon layer may function as a nucleation layer for the second carbon layer. Optionally, in relation to the last coating apparatus 108(k,3), a second power pulse 122 with a higher peak power (e.g., peak voltage) (compared to other coating apparatuses 108(k,m / 3)) may be used. This may function to break the material peaks of the formed layer in order to smooth the layer.

[0195] Generally, the continuous flow system 500 may have two substrate transfer openings through which (at least one) substrate 106 may be transported in and out of the continuous flow system 500. Several processing areas may be formed between these two substrate transfer openings. For example, one or more processing areas may each have one or more coating devices 108. Thus, the coating device 108(k,m) shown in Figure 5A may form, for example, three processing areas (the substrate 106 may be coated on both sides in each processing area).

[0196] Figure 5B shows an exemplary configuration of a continuous flow system 500 having several processing areas between a first substrate transfer opening 502 for sending at least one substrate 106 (e.g., a bipolar plate) into the continuous flow system 500 and a second substrate transfer opening 502 for guiding at least one substrate 106 out of the continuous flow system 500. A vacuum may be present within the continuous flow system 500.

[0197] The flow-through system 500 may have at least one plasma source 506(k) for plasma etching the surface of the substrate 106 (e.g., a bipolar plate). For example, the throughput system 500 may include a first plasma source 506(1) and a second plasma source 506(1) for plasma etching both sides of the substrate 106. Plasma etching may be performed, for example, using argon ion bombardment (e.g., by magnetron sputter etching, by reverse etching, or by processing with an argon ion source).

[0198] Optionally, the substrate 106 (e.g., a bipolar plate) may be heated (e.g., warmed) after plasma etching and then cooled.

[0199] Optionally, the continuous flow system 500 may have one or more coating sources 508(k,o) in addition to the coating device 108(k,m). These may be arranged on both sides in the transport direction 101.

[0200] The coating source 508(k,o) may be, for example, a coating source for magnetron sputtering, arc evaporation, or high-pulse magnetron sputtering.

[0201] In an exemplary process, the bipolar plate may be coated on both sides as a substrate in a continuous production line 500. The bipolar plate may have a surface roughness having, for example, an arithmetic mean height of 0.3 μm or less, preferably 0.2 μm or less, and / or a maximum height of 4.0 μm or less, preferably 2.5 μm or less. In an exemplary method, the surface of the bipolar plate may be cleaned on both sides using a first plasma source 506(1) and a second plasma source 506(1).

[0202] Next, one or more metal layers can be formed on the cleaned surface of the bipolar plate using a plurality of coating sources 508(k,o). The metal layers may be, for example, titanium layers. For example, a first metal layer may be formed on the bipolar plate using a first pair of coating sources 508(k,1), and a second metal layer may be formed on the first metal layer using a second pair of coating sources 508(k,2). (k,1) may be used to form the first metal layer on the bipolar plate, the second pair of coating sources 508(k,2) may be used to form the second metal layer on the first metal layer, and the third pair of coating sources 508(k,3) may be used to form the third metal layer on the second metal layer.

[0203] In one example, the first, second, and third metal layers may each be titanium layers, or a common titanium layer may be formed. The common titanium layer may have a thickness in the range of about 20 nm to about 400 nm, preferably in the range of about 50 nm to about 150 nm. The three metal layers are illustrative, and it is understood that fewer metal layers (e.g., one or two) or more than three metal layers may be formed (the continuous flow system 500 may have corresponding coating sources). The (common) titanium layer can, for example, improve the corrosion resistance of the bipolar plate.

[0204] Subsequently, the layers described herein (for example, as a carbon layer) can be formed on the (common) titanium layer by a coating apparatus 108(k,m). It should also be understood that the number of coating apparatuses shown is illustrative, and the continuous flow system 500 may have more or fewer coating apparatuses 108(k,m). For example, in some embodiments, one-sided processing of the substrate may be performed (resulting in k=1). As described herein, a carbon layer can be formed having one or more of the characteristics specified in Examples 38 to 47, for example (by omitting individual second power pulses 122 and / or by selecting a target pulse length for the first power pulse 120 from a range of about 250 μs to about 350 μs).

[0205] Optionally, the continuous flow system 500 may have one or more cooling regions (e.g., between two consecutive processing regions) to lower the temperature of the substrate (and thus the already formed layer). The cooling regions may include, for example, a cooling plate or another suitable type of cooling.

[0206] The layers (e.g., carbon layers) are produced in the continuous processing system 500 according to the principles described herein, but it is understood that the layers may also be produced in other systems, such as drum coater systems.

[0207] Figure 6 shows a schematic diagram of an exemplary operation sequence 600, where power P is represented as an exemplary time-dependent variable of the pulse over time t.

[0208] The operation sequence 600 includes several phases 601, 603, in which each phase generates at least one laser pulse 114, at least one first power pulse 120, and at most one second power pulse 122. Multiple phases 601, 603 include multiple (e.g., two, three, or four) directly consecutive series of phases 601 (also called phase series) of the first type. In each phase 601 of the first type, exactly one laser pulse 114, exactly one first power pulse 120, and exactly one second power pulse 122 are generated. Multiple phases 601, 603 have one or more phases 603 of the second type, which are placed between two directly consecutive phase series and generate exactly two laser pulses 114, exactly two first power pulses 120, and exactly one second power pulse 122. It should be understood that the number of pulses is illustrative.

Claims

1. A step of controlling the excitation source according to the operating sequence, A step of controlling the power supply according to the aforementioned operation sequence, Includes, The aforementioned operation sequence includes multiple phases, In each of those phases, The excitation source generates an excitation pulse directed towards the target to excite a plasma discharge in the target. In order to electrically supply the plasma discharge from the target, the power supply generates a first power pulse, and / or In order to accelerate the material flow emitted from the target by the plasma discharge away from the target and / or toward the substrate holder, the power supply generates a second power pulse. The aforementioned multiple phases The system comprises one or more first phases, in which the first power pulse and / or the second power pulse are generated for each excitation pulse. Including the second phase, For each second power pulse, two excitation pulses and / or two first power pulses are generated, and / or A method for generating a first power pulse and a second power pulse that partially overlap each other.

2. The first power pulse is transmitted by the target and / or an anode associated with the target, and / or The second power pulse is transmitted by the substrate holder to which the material flow is directed, and / or by an anode associated with the substrate holder. The method according to claim 1.

3. Each of the aforementioned second phases comprises at least two or three first phases. The method according to claim 1 or 2.

4. The first power pulse is generated according to a target pulse length in the range of approximately 250 μs to approximately 350 μs. The method according to any one of claims 1 to 3.

5. The first power pulse is generated according to the target current pulse, and / or The second power pulse is generated according to the target voltage pulse. The method according to any one of claims 1 to 4.

6. The target contains or is made of carbon. The method according to any one of claims 1 to 5.

7. In each of the first and / or second phases, The first power pulse is generated according to a first target time difference from the start of the phase, and the second power pulse is generated according to a second target time difference from the start of the phase, wherein the second target time difference is greater than the first target time difference, and / or The first power pulse is generated according to a first target pulse duration, and the second power pulse is generated according to a second target pulse duration, wherein the second target pulse duration is less than the first target pulse duration. The method according to any one of claims 1 to 6.

8. A computer program configured to cause a processor to perform the method according to any one of claims 1 to 7 when executed by the processor.

9. A computer-readable medium for storing instructions configured to cause a processor to perform the method according to any one of claims 1 to 7 when executed by the processor.

10. A control device comprising one or more processors configured to perform the method according to any one of claims 1 to 7.

11. The control device according to claim 10, The aforementioned power supply, The excitation source and, A target holder for holding the target, comprising a target holder electrically coupled to the power supply, Equipped with, An apparatus wherein the target holder is configured to optionally provide a rotation axis and to rotate the target around the rotation axis.

12. The step of placing the bipolar plate in a vacuum, A step of performing laser-induced arc evaporation in a vacuum by controlling an excitation source and a power supply according to the method of any one of claims 1 to 7, wherein the material flow emitted by the plasma discharge contains carbon and is emitted toward the bipolar plate; A method that includes this.

13. The vacuum is provided by a vacuum chamber, which preferably includes two substrate transfer openings, through which the bipolar plate is transported, a coating region is positioned between the two substrate transfer openings, and a material flow is released into the coating region. Preferably, the control and transport are further configured such that the rate at which the carbon layer is formed on the bipolar plate is 50 nm m / min or more. The method according to claim 12.

14. A step of controlling the excitation source according to the aforementioned operation sequence, In the step of controlling the power supply according to the aforementioned operation sequence, The aforementioned operation sequence includes multiple phases, In each of those phases, An excitation pulse directed towards the target is generated by the excitation source to excite a plasma discharge in the target. In order to electrically supply the plasma discharge from the target, the power supply generates a first power pulse, and / or A step of controlling the power supply, wherein the power supply generates a second power pulse to accelerate the material flow emitted from the target by the plasma discharge away from the target and / or toward the substrate holder. A step in which the operation sequence is updated based on the results of the plasma discharge, thereby the plurality of phases The system comprises one or more first phases, in which the first power pulse and / or the second power pulse are generated for each excitation pulse. Including the second phase, For each second power pulse, two excitation pulses and / or two first power pulses are generated, and / or An update step in which a first power pulse and a second power pulse are generated that partially overlap each other, Methods that include...

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