Method, control device, computer program, and storage medium

Abstract

According to various embodiments, a method (150) may include determining (101) an actual state of a result of a double-sided coating process in which a first layer stack is formed on a front side of a substrate and a second layer stack is formed on a back side of the substrate based on a model implementing an association between the result and a spectral response of the result, and an indication of the actual state of the spectral response, a difference between a first sub-process of the coating process in which the first layer stack is formed and a simultaneous second sub-process of the coating process in which the second layer stack is formed; and controlling (103) the coating process based on the actual state of the result.

Description

[Technical Field]

[0001] Various embodiments relate to methods, computer programs, controllers, and storage media. [Background technology]

[0002] In general, substrates, such as glass substrates, metal substrates, and / or polymer substrates, can be treated, for example, coated by a coating process, so that the chemical and / or physical (e.g., optical) properties of the substrate can be changed. A layer stack can be formed by the coating process (e.g., by chemical vapor deposition and / or physical vapor deposition) to specifically tailor the optical properties of the resulting product, such as its light spectrum. For example, using a vacuum coating system, one or more stacks of several layers (also referred to as layer stacks) can be deposited by the coating process, whose optical interaction with each other is intended to meet the requirements of reflection or transmission properties or color impression. One such application is the coating of optical components, such as lenses, prisms, or mirrors.

[0003] Generally, such coating processes can be controlled, for example, by optical measurements performed at regular intervals on the time-dependent actual state of the coating process outcome. However, the complexity of such control increases considerably with the number of interacting layers, and therefore computer-implemented models are used to supervise (also known as monitoring) the progress of the coating process based on optical measurements.

[0004] According to various embodiments, it is recognized that the feasibility of monitoring the coating process is limited in various applications, including when a substrate is to be coated on both sides, for example with layer stacks of similar structure, preferably simultaneously, and / or when the substrate is made of a transparent material. In particular, reflection measurements as optical measurements are more difficult for layer stacks made of transparent materials because the optical measurements capture both layer stacks, and the same is true for transmission measurements. For example, the greater the similarity between the layer stacks, the greater the risk that it will be difficult to distinguish them from each other using optical measurements, which can result in the coating process being inaccurately controlled and, as a result, high demands on the results being rarely met. For example, layer thicknesses determined by optical measurements may no longer be uniquely assigned to the respective stacks, which makes reliable control impossible.

[0005] In this context, it is illustratively recognized that this risk can be reduced if one or more differences between the layer stacks are taken into account (in addition to the optical measurements). This consideration illustratively improves the data basis for control (e.g., through additional boundary conditions). However, a particular challenge exists when these layer stacks have a uniform target structure and are both recorded by optical measurements and formed simultaneously (e.g., overlapping in time). In this case, it is recognized that usable differences between the layer stacks can be generated by differences in the time at which the optical measurements are performed or their actual state at each time. This can be achieved, for example, by forming the two layer stacks at different speeds or times. Such a procedure maximizes the overlap in time between the formation of the two layer stacks, resulting in a substrate coating that takes less time overall and is therefore more cost-effective. Summary of the Invention

[0006] According to various embodiments, methods, computer programs, controllers, and storage media are provided that enable one or more of the following: - Substrates can be coated on both sides, possibly simultaneously, which increases the throughput of the coating process and therefore its cost-effectiveness, without the need for tool changes; - High demands on results are no longer achieved only when the layer stack is deposited sequentially; - It follows, exemplarily, that a high calibration effort is avoided, since higher variations in the sub-processes, which in reality occur anyway, can be tolerated in order to stimulate this difference; - To improve the data base, additional sensor technology (e.g. for reflectometry) will not necessarily be required. [Brief explanation of the drawings]

[0007] [Figure 1] 1A and 1B show schematic side and cross-sectional views of processing apparatus according to various embodiments. [Figure 2A] 2A and 2B show schematic side and cross-sectional views, respectively, of processing apparatus according to different embodiments. [Figure 2B] 2A and 2B show schematic side and cross-sectional views, respectively, of processing apparatus according to different embodiments. [Figure 3A] 3A and 3B show, in schematic side and cross-sectional views, respectively, the results of a coating process according to different embodiments. [Figure 3B] 3A and 3B show, in schematic side and cross-sectional views, respectively, the results of a coating process according to different embodiments. [Figure 4A] 4A and 4B show schematic diagrams of spectral responses according to different embodiments. [Figure 4B] 4A and 4B show schematic diagrams of spectral responses according to different embodiments. [Figure 5A] 5A-5C show schematic diagrams of spectral responses according to different embodiments. [Figure 5B]5A-5C show schematic diagrams of spectral responses according to different embodiments. [Figure 5C] 5A-5C show schematic diagrams of spectral responses according to different embodiments. [Figure 6A] 6A and 6B each show a different schematic view of a coating process according to a different embodiment. [Figure 6B] 6A and 6B each show a different schematic view of a coating process according to a different embodiment. [Figure 7] 1A-1C show schematic top and cross-sectional views of a vacuum device according to various embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown, by way of example, specific embodiments in which the present invention may be practiced. In this regard, directional terms such as "top," "bottom," "front," "rear," "front," and "back" are used with reference to the orientation of the figures being described. Because components of the embodiments may be arranged in multiple different orientations, the directional terms are for illustrative purposes only and are not intended to be limiting in any way. It is understood that other embodiments may be used and structural or logical changes may be made without departing from the scope of protection of the present invention. It should be understood that the features of the various exemplary embodiments described herein can be combined with each other unless specifically stated otherwise. Therefore, the following detailed description should not be construed in a limiting sense, and the scope of protection of the present invention is defined by the appended claims.

[0009] In the context of this description, the terms "connected," "connected," and "coupled" are used to describe both direct and indirect connections (e.g., ohmic and / or conductive, e.g., conductive connections) and direct or indirect couplings. In the drawings, identical or similar elements are labeled with the same reference numerals where appropriate.

[0010] The actual state of an entity (e.g., a device, system, or operation, i.e., a process) can be understood as the actual or sensorily measurable state of the entity. The desired state of the entity, i.e., its specification, can be understood as the target state of the entity. Control can be understood as the intended influence on the current state of the entity (also referred to as the actual state). The current state can be changed according to the specification (also referred to as the target state), for example, by a manipulator, by modifying one or more operating parameters of the entity (in that case, also referred to as manipulated variables). Regulation can be understood as control in which state changes are also counteracted by disturbances. For this purpose, the actual state is compared with the target state, and the entity is influenced, for example, by a manipulator, in such a way that the deviation of the actual state from the target state is minimized. Thus, in contrast to pure forward sequential control, closed-loop control realizes the continuous influence of an output variable on an input variable, which is achieved by a so-called control loop (also referred to as feedback). In other words, this may be understood to mean that closed-loop control may be used instead of or in addition to open-loop control (or open-loop controlling), or that closed-loop control may be used instead of or in addition to closed-loop control.

[0011] The state of a controllable apparatus (e.g., a coating apparatus) or a controllable process (e.g., a coating process) can be defined as a point (also referred to as an operating point) in a space (also referred to as a state space) spanned by variable parameters (also referred to as operational parameters) of the apparatus or process. Thus, the state of the apparatus or process is a function of the respective values ​​of one or more operational parameters that represent the state of the apparatus or process. The actual state can be determined based on measurements (e.g., by a sensing component) of one or more operational parameters (also referred to as control variables). Examples of operational parameters of a process (e.g., a coating process or a sub-process thereof) include the time at which the process is started or restarted, the time at which the process is paused or terminated, the duration for which the process is paused or performed, the speed at which the process is performed, the temperature to which the process is exposed, and the pressure to which the process is exposed. For example, speed can be expressed as a rate (change per time), such as a coating rate (e.g., expressed as an increase in coating thickness on a substrate per time) and / or a release rate (e.g., measured as an increase in coating thickness on a rate sensor per time). With respect to sputtering devices, the ejection rate is also referred to as the atomization rate.

[0012] Thus, the state of the system can represent the state of each coating process in the system, and vice versa. The actual state of each process (e.g., a coating process or each sub-process thereof) can be sensed by a sensing unit (e.g., having one or more sensors). For each controlled variable, one or more sensors can be used that are configured to sense a variable (also called a measured variable) that represents or is the controlled variable.

[0013] A sensor (also referred to as a detector) may be understood as a transducer configured to sense a characteristic (e.g., qualitative or quantitative) of its environment that corresponds to the sensor type as a measurement variable, such as a physical, chemical, and / or material property. The measurand is a physical quantity (also referred to as a control variable) to which the measurement by the sensor applies. Depending on the complexity of the environment measured by the sensor, the sensor may be configured to distinguish between two or more separate states of the measurement variable (also referred to as a measurement switch) or to sense the measurement variable quantitatively. An example of a sensed measurement variable is, for example, a gas inflow (e.g., sensed as a flow rate), the actual state of which may be converted into a measurement value using a sensor.

[0014] Each sensor can be part of a measurement chain with a corresponding infrastructure (e.g., a processor, a storage medium, and / or a bus system). The measurement chain can be configured to control the corresponding sensor, process its recorded measurement variables as input variables, and based on this provide electrical signals representative of the recorded input variables as output variables. For example, the output variables can indicate measured values. The measurement chain can, for example, be or be implemented by a so-called control device.

[0015] In the following, reference will be made in particular to reactive processes in which a chemical reaction occurs. For example, one or more processes (e.g., a coating process or sub-processes thereof) may include a reactive sputtering process in which one or more reactive gases (e.g., m reactive gases) (e.g., m=1, m>1, or m>2) are supplied that form chemical bonds with a coating material (also referred to as a target material) to be deposited on a substrate (in which case, also referred to as a layer-forming material). It can be understood that a coating process does not necessarily have to be reactive. A quantity representing a material involved in a chemical reaction in a reactive coating process may represent a corresponding other material that does not participate in a chemical reaction in a non-reactive coating process. Thus, what is described for a reactive coating process can be applied to a non-reactive coating process as well, and vice versa.

[0016] According to various embodiments, reference is made to physical vapor deposition (PVD), with, for example, a sputtering process, as an exemplary coating process. It should be understood that what is described for PVD can equally be applied to chemical vapor deposition (CVD). In contrast to CVD, in PVD, a solid material is first converted into a gas phase (also known as a gas phase or vapor), which forms a layer. In PVD, the gas phase of the target material can optionally chemically react with a reactant gas to form a compound that is incorporated into or forms the layer. Thus, in a PVD chemical reaction, two or more materials combine to form a compound.

[0017] In chemical vapor deposition, a gaseous starting compound (also referred to as a precursor or reactant) is split into at least two reaction products, at least one of which is incorporated into the coating, and optionally one reaction product is removed (e.g., by pumping) from the coating process as excess. Optionally, CVD can be performed by a plasma in which the precursor splits.

[0018] Plasma can be formed by a so-called working gas (also known as a plasma-forming gas). According to various embodiments, the working gas can include a gaseous material that is inert, i.e., that participates little or no chemical reaction. For example, the working gas can be, be defined by, or be adapted to the target material used. For example, the working gas can be a gas or gas mixture that does not react with the target material to form a solid. The working gas can include, for example, a noble gas (e.g., helium, neon, argon, krypton, xenon, radon) or multiple noble gases. Plasma can be formed from the working gas, for example, by essentially atomizing the target material. If a reactive gas is used, it can have a higher chemical reactivity than the working gas, for example, with respect to the target material. In other words, the atomized target material can react faster (i.e., form more reaction products per time) with the reactive gas (if present) than with the working gas (e.g., if it were to completely chemically react with the working gas). The reactive gas and the working gas may be supplied together or separately as a process gas (eg, as a gas mixture), for example by a gas supply device.

[0019] The reactive gas can include a gaseous material that can react with the target material (e.g., atomized target material) and / or be incorporated into the deposition layer through a chemical reaction. For example, if a target material that can form a nitride (e.g., aluminum nitride) is used, or if a nitride of the target material is to be deposited, the reactive gas can contain or be formed from nitrogen. For example, if a target material that can form an oxide (e.g., aluminum oxide) is used, or if an oxide of the target material is to be deposited, the reactive gas can include or be formed from oxygen. The reactive gas can include or be formed from a gas mixture (reactive gas mixture) of several gases that react with the target material and / or the deposition layer, such as oxygen and nitrogen when an oxynitride (e.g., aluminum oxynitride) is to be deposited. The reactive gas mixture can include, for example, primarily (i.e., greater than 50%) oxygen, for example, to deposit an oxide or oxynitride. Examples of reactive gases include molecular oxygen, molecular nitrogen, nitric oxide, carbon oxide, hydrogen sulfide, methane, gaseous hydrocarbons, molecular fluorine, molecular chlorine, ozone, or other gaseous materials.

[0020] In one exemplary implementation, coating can involve vacuum-assisted coating (e.g., the formation of individual layers of a layer stack) with the aid of, for example, an electric discharge (also referred to as plasma). For this purpose, a plasma-forming (e.g., inert) gas can be ionized by a cathode, and the material to be deposited (also referred to as a target) can be atomized (also referred to as sputtering) by the plasma formed in the process. The atomized material can then be delivered to a substrate and deposited thereon to form a layer (also known as a coating). A variant of cathode sputtering is magnetron sputtering, known as magnetron sputtering, such as reactive magnetron sputtering or non-reactive magnetron sputtering. The formation of plasma can be assisted by a magnetic field, which can affect the ionization rate of the plasma-forming gas. The magnetic field can be generated by a magnet system, which forms a plasma channel in which the plasma can form. In the case of sputtering, the coating material can be positioned as a solid (also referred to as a target) between the plasma channel and the magnetic system, so that the target is penetrated by the magnetic field and a plasma channel can form on the target. A plasma-forming gas (e.g., argon), along with an optional reactive gas, can form the process gas in which sputtering occurs. The reactive gas can be used for reactive magnetron sputtering.

[0021] In the following, reference is made to methods comprising controlling a coating process, which may be performed, for example, by controlling one or more operating elements (also referred to as positioning). In this context, reference is also made to a control device or a code segment. A control device (also referred to as a control device) may be configured to perform one or more of the methods described herein. To this end, the control device may have a processor configured to perform the respective method. For example, the processor may be configured to issue corresponding instructions for controlling. Alternatively, or in addition, the processor may be configured to receive and process corresponding instructions and signals. The instructions received by the processor may be implemented, for example, by a code segment stored in a non-transitory data memory. For example, a code segment may have at least one instruction and / or one or more instructions that, when executed by the processor, cause the processor to perform one of the methods.

[0022] The term "controller" may be understood as any type of logic-implemented entity, and may include, for example, a processor (and, e.g., corresponding circuitry) capable of executing software stored in a storage medium, firmware, or a combination thereof, and issuing instructions based thereon. A controller may, for example, be constituted by code segments (e.g., software). A controller may, for example, include or be formed from a programmable logic controller (PLC).

[0023] According to various embodiments, the data storage device (also more generally referred to as a storage medium) may be a non-transitory data storage device. For example, the data memory may include or be formed from a hard disk and / or at least one semiconductor memory (e.g., read-only memory, random access memory, and / or flash memory, etc.). The read-only memory may be, for example, an erasable programmable read-only memory (EPROM). The random access memory may be a non-volatile random access memory (NVRAM—also referred to as “non-volatile random access memory”). For example, the data memory may store one or more of a code segment implementing a method, a model or at least its parameters, or one or more indications of differences between two sub-processes of a coating process.

[0024] The term "processor" may be understood as any type of entity that enables processing of data or signals. For example, data or signals may be manipulated according to at least one (i.e., one or more) specific functions performed by the processor. A processor may comprise or be formed from an analog circuit, a digital circuit, a mixed-signal circuit, a logic circuit, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a programmable gate array (FPGA), an integrated circuit, or any combination thereof. Any other type of implementation of the respective functions described in more detail below may also be understood as a processor or logic circuit, e.g., a virtual processor (or virtual machine) or multiple decentralized processors, which are interconnected, for example, by a network, spatially distributed in any desired manner, and / or have any desired share in the implementation of the respective functions (e.g., computing load distribution among processors). The same generally applies to differently implemented logic for performing the respective functions. It will be understood that one or more of the method steps described in detail herein may be performed (e.g., implemented) by a processor through one or more specific functions performed by the processor.

[0025] The term "actuator" (including, for example, actuator) may be understood as a transducer configured to affect a state, process (e.g., a coating process), or device in response to control of the actuator. An actuator may convert a control signal supplied thereto (by which control is performed) into mechanical movement or a change in a physical variable, such as pressure or temperature. An electromechanical actuator may, for example, be configured to convert electrical energy into mechanical energy (e.g., through movement) in response to control.

[0026] A manipulator may be configured to influence the actual state (also known as the operating point) of a process (e.g., its manipulated variables) delivered by that manipulator. The influence may be direct or indirect. For example, the manipulated variable and the controlled variable may be different from each other. In that case, the controlled variable (e.g., pressure) may be a function of one or more manipulated variables (e.g., gas flow rate).

[0027] For example, the operating unit can change the voltage by which the plasma is supplied as the operating variable, thereby changing the coating speed, spray rate, or layer thickness as the controlled variable. For example, the operating unit can change the gas inflow as the operating variable, thereby changing the pressure as the controlled variable. For example, the operating unit can change the working gas inflow as the operating variable, thereby changing the atomization speed or layer thickness as the controlled variable. For example, the operating unit can change the reactive gas inflow as the operating variable, thereby changing the chemical composition of the plasma or coating as the controlled variable.

[0028] With respect to the control of an operating element, reference is made in particular to the more easily understood control variable or its control value that is influenced by the operating element. What is said in this respect can equally be applied to the control variable or its control value that is supplied to the operating element for control, and vice versa. In other words, the operating element functions as a converter that converts a control signal into a control variable or its control value, such that the control value is a function of the control value.

[0029] According to various embodiments, the provided control and / or regulation can be used to stabilize optical product properties (color, transmittance, reflectance), for example by adjusting layer thickness. According to various embodiments, the or each substrate can comprise or be formed from a foil and / or a glass plate.

[0030] For example, one of the layer stacks can comprise or be formed from an optical anti-reflection multilayer system, which can comprise a plurality of transparent and / or dielectric materials with different refractive indices and a stack of a plurality of multilayer groups, optionally with different total layer thicknesses, each of which comprises a plurality of layers, a first of which comprises or consists of a first material of the plurality of materials and a second of which comprises or consists of a second material of the plurality of materials.

[0031] For example, the layer stack can include or be formed from an optically low-emission multilayer system. The low-emission multilayer system can include a dielectric base layer assembly (e.g., having one or more layers) and a dielectric cap layer assembly (e.g., having one or more layers), and a functional layer assembly (e.g., having one or more layers) including a metal functional layer disposed between the base layer assembly and the cap layer assembly, the cap layer assembly optionally including at least one protective layer. The protective layer can include, for example, a semimetal (e.g., silicon) and / or a nonmetal (e.g., nitrogen), their nitrides and / or their oxides. In some embodiments, the metal functional layer can be omitted.

[0032] According to various embodiments, an object (e.g., a substrate, a material, a layer stack, and / or any layer thereof) may be semi-transparent. In the context of this description, the term "semi-transparent" (e.g., transparent or at least semi-transparent) may be understood to mean that an object (e.g., a substrate or a layer or a material) has a transmittance such that a greater proportion of electromagnetic radiation (e.g., light) impinging on it passes through it than is absorbed and / or reflected by it, for example. A semi-transparent object can be, for example, semi-transparent (partially translucent). In other words, the transmittance within a transmissive region can be greater (e.g., at least 2, 3, 5, or 10 times greater) than the reflectance and / or the absorbance, for example, the sum of these.

[0033] Transmission coefficient (also referred to as transmittance) may represent the fraction of electromagnetic radiation (e.g., visible light) that passes through an object (e.g., a substrate). Reflectance (also referred to as reflection coefficient) may represent the fraction of incident electromagnetic radiation that is reflected (e.g., re-emitted) by an object. Reflectance may take into account directionally reflected radiation (reflected back), diffusely reflected radiation, and / or re-emitted radiation. Absorbance (also known as absorption coefficient) may represent the fraction of incident electromagnetic radiation that is absorbed (i.e., taken up and / or swallowed) by an object, for example, by converting it to heat.

[0034] A transparent object (e.g., a substrate, a material, a layer stack, and / or any layers thereof) can have a transmittance (transmission coefficient) greater than about 50%, such as greater than about 60%, such as greater than about 70%, such as greater than about 80%, such as greater than about 90%. For example, the transmittance can be in the range of about 70% to about 99%.

[0035] Generally, the transmittance can depend on the wavelength of the electromagnetic radiation, according to the optical properties of the object. For example, a layer stack can be transparent to one or more wavelength ranges while being opaque to, i.e., filtering out, one or more further wavelength ranges. The filtered-out wavelength ranges can be absorbed and / or reflected.

[0036] According to various embodiments, such information regarding optical properties (e.g., transmittance, reflectance, and / or absorptance) may relate to a particular wavelength range (also referred to as a transmission range) of electromagnetic radiation, such as the wavelength range of visible light (i.e., the wavelength range from about 380 nm to about 780 nm), or a cutoff wavelength, or 550 nm.

[0037] According to various embodiments, the dielectric object (e.g., material or structure, e.g., layer) may be, for example, 10 -6A dielectric object may be understood to be electrically insulating, such as having a conductivity lower than Siemens per meter. A dielectric object may, for example, comprise or be formed from an oxide and / or nitride ceramic (e.g., as a compound of a metal). Oxide may be understood to mean that the object comprises or is formed from an oxygen compound (e.g., a metal oxide). Nitride may be understood to mean that the object comprises or can be formed from a nitrogen compound (e.g., a metal nitride). A dielectric object may, for example, be transparent.

[0038] For purposes of this description, a metal (also referred to as a metallic material) may have (or be formed from) at least one metallic element (i.e., one or more metallic elements), such as 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), indium (In), calcium (Ca), hafnium (Hf), and / or samarium (Sm).

[0039] To perform double-sided coating, where the formation of the individual layers is controlled by an optical monitoring system, it may be necessary to deposit the individual layers (also called individual layers) one after the other, since the layer thickness of each layer cannot be uniquely determined, especially when the layer stacks formed on the front and back sides are the same. In this case, simultaneous coating is only possible in a time-controlled manner or by determining the rate using a vibrating crystal as a rate sensor. This is not sufficient for precision optical requirements.

[0040] According to various embodiments, it is possible to independently achieve nearly simultaneous coating of both sides of a coating system (also referred to as double-sided coating) controlled by optical monitoring. Simultaneous coating can be understood to mean that the percentage of the total duration of the coating process during which the substrate is coated on only one side is less than the percentage of the time during which the substrate is coated on both sides (or 50%, or 25%, or 10%). Thus, the total time for the double-sided coating process is shorter than if the same result were produced by single-sided coating.

[0041] By judiciously selecting the operating parameters of the coating process (also referred to as coating parameters), such as the start time of the coating process or its sub-processes, sufficient information is provided to determine the layer thickness and coating speed in situ (e.g., without breaking the vacuum) from the light spectrum, even when the same layer system (e.g., transparent layer) is deposited on the front and back, as will be explained in more detail below.

[0042] FIG. 1 shows a schematic side or cross-sectional view of a processing apparatus 100 according to various embodiments, which includes a control apparatus 102 and a vacuum apparatus 104.

[0043] The controller 102 may include at least one (e.g., one or more) processors configured to execute the method 150. For example, the controller 102 may be configured to execute code segments (e.g., implementing instructions) that cause the processor to execute the method 150. For example, the code segments may be stored locally by a computer-readable medium of the controller 102 or may be provided at least in part by a cloud. In this regard, it may be understood that what is described with respect to the controller 102 may equally apply to computerized implementations of other types of methods that do not necessarily require, for example, a controller 102 and / or a computer-readable medium.

[0044] The vacuum assembly 104 may include a vacuum chamber 802, a transport device 112 for transporting a substrate along a transport path within the vacuum chamber 802, a coating device 106 for performing a coating process adapted to coat a substrate on both sides (also referred to as a double-sided coating process), and a measurement unit 108.

[0045] An exemplary implementation of the transport device 112 includes a substrate carrier 110 (also referred to as a carrier) disposed within the vacuum chamber 802 and an operating portion 112g configured to be controlled in response to applying a mechanical force to the substrate carrier 110, thereby causing the substrate carrier 110 to move (e.g., rotate).

[0046] An exemplary implementation of the substrate support 110 includes one or more (e.g., plate-like) supports having one or more substrate support regions 110a, 110b, each of which is penetrated by a through opening and has a support surface extending into the through opening on which a substrate can be placed.

[0047] This or an alternative exemplary implementation of the substrate carrier 110 is rotatably mounted such that the transport path runs along a curved path (e.g., a closed path). For example, the substrate carrier 110 may undergo several rotations or several oscillatory motions during the coating process, e.g., for each layer of a layer stack.

[0048] The method includes, at 101, determining an actual state of a result of a double-sided coating process (also referred to as a coating result), at 103, driving the coating process based on the actual state of the coating result, optionally, at 105, driving a measurement unit 108 for sensing the actual state of the spectral response of the coating result, and optionally, at 107, initializing a model (e.g., based on process differences).

[0049] The coating process can be configured to form two layer stacks (also referred to as coatings), a first layer stack formed on a first side of the substrate by a first sub-process, and a second layer stack formed on a second side of the substrate opposite the first side by a second sub-process. In this regard, reference is made to a "front side" and a "back side" to facilitate distinction between the two sides of the substrate and corresponding terminology, although it will be understood that this is merely exemplary (e.g., no preference is intended) and may likewise be applied interchangeably.

[0050] The target state of the coating result (e.g., the result at the end of the coating process) comprises a substrate 250, a first layer stack 302 (also referred to as a front coating) on ​​a front side of the substrate 250, and a second layer stack 304 (also referred to as a back coating) on ​​a back side of the substrate 250. It is understood that the actual state of the coating result may differ from the target state of the coating result, for example, in one or more layers (e.g., per layer stack).

[0051] Here, and particularly below, reference will be made to the description of a single layer stack for ease of understanding, in which case it will be understood that what is described therein may equally apply to each of two layer stacks, for example, but not necessarily, if the two layer stacks should meet the same specifications. Examples of specifications that at least one (or each) of the two layer stacks may meet include the spatial sequence of layers of different chemical composition, the chemical composition of one or more layers, the number of layers of different chemical composition, the total thickness, and the spectral response.

[0052] The coating apparatus 106 includes at least one (one or more) coating material sources 106a, 106b configured to perform a subprocess for forming a layer stack, for example, for each layer stack of two layer stacks. A transport path may be disposed between the two coating material sources 106a, 106b. The at least one coating material source 106a, 106b may include, for example, one coating material source for each layer of the layer stack. Here, reference is made to two coating material sources per layer stack, i.e., two first coating material sources for forming the front coating and two second coating material sources for forming the back coating. It should be understood that what is described herein may also apply to any different number of coating material sources per layer stack. In general, the number of coating material sources per layer stack may depend on how many layers with different properties are formed per layer stack.

[0053] An exemplary implementation of the at least one coating material source 106a, 106b includes, for example, a sputtering device (and optionally an ion source) as the coating material source 106a, 106b for each layer of the layer stack.

[0054] An exemplary implementation of the sensing unit is configured to sense a transmission spectrum as the spectral response. To this end, the sensing unit comprises a source of optical radiation (e.g., a light source) and one or more sensors, with a transmission path running between them. It can be understood that what is described herein for a transmission spectrum can equally be applied to other types of spectra, such as a reflection spectrum and / or a spectrum determined by ellipsometry (i.e., by an ellipsometer).

[0055] The determination of the actual state 101 may be based on a model that performs a correlation between the coating result (e.g., its state, e.g., its target state or actual state) and the resulting spectral response (e.g., its estimate). For example, the model may have an algorithm by which the state and the spectral response of the coating result can be mapped to each other. An implementation of this can be found, for example, in so-called design software for optical coatings, such as the “OptiLayer” software from OptiLayer GmbH (as of January 2023). This offers, for example, the possibility to simulate the spectral response of a layer stack based on a model of the layer stack that takes into account the individual layers, their sequence, thickness, and optical density. Alternative or additional implementations are described in DE 102018101173 A1 and DE 102020124934 A1.

[0056] The actual state determination 101 may further be based on an indication of a difference (also referred to as a process difference) between a first sub-process of the coating process by which the front coating is formed (also referred to as a front process) and a concurrent second sub-process of the coating process by which the back coating is formed (also referred to as a back process). Process difference is described in more detail below.

[0057] In an exemplary implementation, the method 150 includes determining 101 an actual state of a structure of a multilayer system (as a result of a coating process) having a substrate, a first layer stack on a front surface of the substrate, and a second layer stack on a back surface of the substrate based on a model that performs a correlation between the structure of the multilayer system and the spectral response (e.g., transmission spectrum) of the multilayer system, an indication representing a difference between the actual state of the spectral response sensed by a sensor and an operating state of the spectral response (transmission spectrum) of the multilayer system, and an indication representing a difference between the actual state of the sensed spectral response and an operating point (e.g., at which they are started) between a first sub-process of the coating process in which a first layer stack is formed and a simultaneous second sub-process of the coating process in which a second layer stack is formed, and controlling 105 the first sub-process and / or the second sub-process based on the actual state of the multilayer system.

[0058] 2A and 2B show schematic side and cross-sectional views of a processing apparatus 100 according to various embodiments 200a and 200b, respectively, illustrating a substrate 250 and a transport path 111. Also shown is an exemplary implementation of a coating apparatus 106, which includes two first coating material sources 106a and 116a for forming a front-side coating and two second coating material sources 106b and 116b for forming a back-side coating. The coating material sources 106a and 106b, configured as silicon oxide sources, and the coating material sources 116a and 116b, configured as niobium oxide sources, are positioned above and below the transport path 111.

[0059] In the context of dielectric coating materials (e.g., oxides, nitrides, and / or oxynitrides), it can be understood that the coating material source can be configured to provide the dielectric coating material as a layer-forming material, or can be configured to emit a metal coating material that is later converted (e.g., by chemical reaction) into a dielectric layer-forming material, for example, after the metal coating material has been deposited on the substrate.

[0060] Additionally, the transport path 111 may extend through one or more measurement areas 282 of the processing equipment, each measurement area having a light source 202 and a sensor 212 of the measurement section 108 .

[0061] Also shown is a spectrometer 262 as an exemplary part of a measurement chain implemented, for example, by the controller.

[0062] 3A and 3B show schematic side and cross-sectional views, respectively, of the results of a coating process (also referred to as coating results) according to various embodiments 300a, 300b.

[0063] Each of the two layer stacks 302, 304, with the substrate 250 disposed therebetween, can have multiple layers, adjacent ones of which differ from one another in one or more of their layer thickness, their chemical composition, and / or their optical refractive index. Alternatively, or in addition, adjacent ones of the multiple layers may differ in that they are optically transmissive (e.g., transparent or translucent) and / or dielectric (i.e., made of a material having this property).

[0064] According to embodiment 300b, each of the layer stacks has one or more multilayer groups (e.g., stacks thereof), each multilayer group having a first layer and an adjacent second layer disposed between the first layer and the substrate 250, which differ from each other in one or more of their layer thicknesses 362 (referred to herein as d1, d2, ..., d4), their chemical compositions 364, and / or their optical refractive index.

[0065] In an exemplary embodiment, the first layer comprises silicon oxide and the second layer comprises niobium oxide, both of which are optically transparent and dielectric, although it can be understood that the first and second layers can each comprise any suitable material that meets the optical property requirements.

[0066] 4A and 4B show different spectral responses according to different embodiments 400a, 400b, respectively, in a schematic diagram showing transmission coefficient T versus wavelength λ (in nanometers). The illustrated spectral responses can be determined as actual conditions, for example, by sensor means (i.e., by a sensor), or can be determined as target conditions by a model, for example, where these serve as specifications for the optical properties of the resulting coating.

[0067] 5A-5C show schematic diagrams of spectral responses according to different embodiments 500a, 500b, 500c for different actual states of the coating result, here indicated at times t1, t2, and t3 over the course of a coating process. The illustrated spectral responses can be, for example, recorded by a sensor (i.e., by a sensor) as actual states, such as, for example, as the temporal evolution of the spectral response during the construction of a layer stack, or can be determined by a model as target states, for example, where these serve as specifications for the optical properties of the coating result in the form of target states.

[0068] The spectral response according to embodiment 500a corresponds substantially to that of the substrate, which may be the case when the coating process has just begun, the spectral response according to embodiment 500b corresponds to that of a partially completed coating stack, and the spectral response according to embodiment 500c corresponds to a completed layer stack.

[0069] 6A and 6B show various schematic diagrams 600a, 600b of a coating process according to various embodiments, where the coating process is plotted against time t and a comparison is shown between a front side process 601 and a back side process 603. The coating process may, for example, be performed according to a cycle Z including a first phase 615 (also referred to as a start phase), a second phase 611 (also referred to as a double side coating phase), and a third phase 613 (also referred to as an end phase), where, for example, the substrate is transported (e.g., uninterrupted).

[0070] Each cycle is associated with a layer of a layer stack that is formed from layer-forming material by the front side process 601 and the back side process 603 in that cycle. For example, the layer-forming material is provided in a transport path and / or in a coating area through which the substrate is moved along the transport path (e.g., by a pendulum or rotational movement of the substrate carrier). In general, immediately successive cycles may differ from each other in the layer-forming material that forms the layers of the layer stack assigned to them.

[0071] Hereinafter, reference will be made to the kth (1≦k, e.g., 2≦k, e.g., 3≦k) cycle, but what is described therein may equally apply to the (k+1)th cycle (if present) and / or the (k−1)th cycle (if present). The kth cycle may, for example, be configured to form the kth layer of the layer stack from a kth layer-forming material (e.g., niobium oxide) by a kth coating material source 106a of the coating apparatus. The kth coating material source 106a is adapted to provide the kth layer-forming material (e.g., niobium oxide) to the transport path and / or within the coating zone through which the substrate is moved along the transport path (e.g., by a reciprocating or rotating motion of the substrate carrier). For example, the kth layer-forming material may be different from the (k+1)th layer-forming material (e.g., silicon oxide), if present, and / or different from the (k−1)th layer-forming material (e.g., silicon oxide), if present, and / or identical to the (k+z)th layer-forming material (2=z or 3=z).

[0072] In the double-side coating phase 611 of the kth cycle, the front side process 601 and the back side process 603 can be performed (operation state=ON), for example, simultaneously and / or for the same duration, thereby providing the kth layer forming material.

[0073] For example, in the double-side coating step 611 and / or the termination step 613 of the kth cycle adjacent to the subsequent (k+1)th cycle, the front side process 601 may be interrupted (operation state=OFF) before the back side process 603 with a time delay, thereby completing the formation of the kth layer of the front side coating before the formation of the kth layer of the back side coating. For example, the front side process 601 may be interrupted by a time interval t2 (also referred to as an end time difference) before the back side process 603 is interrupted. The end time difference t2 may be, for example, the duration of the termination step 613.

[0074] For example, in the double-side coating step 611 and / or the start step 615 of the kth cycle adjacent to the preceding (k-1)th cycle, the backside process 603 may be started (e.g., resumed) after the frontside process 601 with a time delay (operation state=ON). For example, the start (e.g., resume) of the backside process 603 may occur a time interval Δt (also referred to as a reference time difference) before the start (e.g., resume) of the frontside process 601. The reference time difference Δt may be, for example, the duration of the start step 615.

[0075] For example, consecutive cycles may be consistent in the reference time difference Δt. Alternatively, or in addition, consecutive cycles may differ from one another in the layer formation material and / or the duration of the first phase 611.

[0076] Diagram 600b shows the layer thickness as a function of time t for the exemplary case where the layer formation rate r1 of the front side process 601 is equal to the layer formation rate r2 of the back side process 603, which is not necessarily the case. As shown, the actual layer thickness of the layer formed by the front side process 601 increases as a function of time t and the layer formation rate until it reaches the target layer thickness d1 at the end of the double side coating phase 611. This occurs in the back side process 603 at the end of the termination phase 613.

[0077] If the front process 601 and the back process 603 provide the same layer formation rate (also referred to as coating rate), the end time difference t2 can be, but is not necessarily, equal to the reference time difference Δt (in which case it is also referred to as the layer formation difference). If the layer formation rate r1 of the front process 601 is greater than the layer formation rate r2 of the back process 603, the end time difference t2 can be greater than the reference time difference Δt.

[0078] The difference in the end times may be based, for example, on the actual state of the coating result determined in 101, e.g., a comparison of this with a corresponding target state. For example, the backside process 603 may be further along than it should be and therefore be interrupted at the same time as the frontside process 601 (t U =0). For example, determining the actual state of the coating result 101 may reveal that the layer thickness of the layer formed by the front side process 601 is less than it should be and is therefore interrupted simultaneously with the back side process 603.

[0079] In exemplary implementation 1, the reference time difference Δt is used as a process difference that can be, for example, more than 1% (or more than 5% or more than 10%) of the duration of the double-side coating step and / or can be greater than about 1 second (s) and / or less than about 20 s, for example, in the range of about 5 s to about 10 s. Alternatively, or in addition, the reference time difference Δt can be greater than the time required for several rotations of the substrate carrier (e.g., more than 10, or more than 50, or more than 100).

[0080] In exemplary implementation 2, configured, for example, according to implementation 1, the end time difference is used as a process difference, which can be, for example, greater than 1% (or greater than 5% or greater than 10%) of the duration of the double-sided coating stage, and / or can be greater than about 1 second (s) and / or less than about 20 s, for example, in the range of about 5 s to about 10 s.

[0081] In exemplary implementation 3, configured, for example, according to implementation 1 or 2, the layer formation difference is used as a process difference that may have, for example, the layer formation rate r1 of the front process 601 and the layer formation rate r2 of the back process 603 differing by more than 1% (or 5% or 10%).

[0082] More generally, the process differential may provide a difference 620 (also referred to as a coating thickness differential) between the actual coating thickness of the coating formed by the front side process 601 and the actual coating thickness of the coating formed by the back side process 603. The layer thickness differential 620 may exist, for example, from cycle to cycle and / or at least during (e.g., at the end of) the double side coating stage 611. The coating thickness differential 620 is generally a function of the coating formation differential and the reference time difference Δt.

[0083] The greater the difference in coating thickness and / or the sooner the difference in coating thickness meets the criteria (e.g., exceeds a threshold) in the initiation stage 615, the better the model can be used to distinguish the actual conditions of the front and back coatings from each other.

[0084] For example, the difference in coating thickness (at least in the initial stage 615) may be greater than 2.5 nm, 5 nm, or 10 nm, and / or the criteria may be met if, for example, the difference in determined coating speed is <5%, <2%, or <1%.

[0085] In an exemplary implementation, the following is done (e.g., several times per cycle or at least per first stage): based on the actual state of the spectral response of the coating result, a time-dependent actual state of the coating result is determined by a model, the actual state of the coating result is compared with a (e.g., time-independent) target state of the coating result, and the coating process is controlled based on the results of the comparison.

[0086] 7 shows a schematic top view or cross-sectional view of the vacuum device 104 according to various embodiments 700, further comprising a reactor 702 (e.g., an ion source) configured to oxidize the coating material emitted from the coating material sources 106 a, 116 a into a layer-forming material. The components 106 a, 116 a, 702 shown here disposed above the transport path 111 may additionally be disposed below the transport path 111 as analogs of the same type.

[0087] Above and below the transport path 111 are arranged coating material sources 106a, 106b configured as silicon oxide sources, which are provided by a Si target (e.g., as part of a sputtering device) and a reactor 702. Above and below the transport path 111 are further arranged coating material sources 116a, 116b configured as niobium oxide sources, which are provided by a NbO xThe target (eg, as part of a sputtering device) and reactor 702 are provided.

[0088] It may further be understood that the model may be based on one or more of the following information: sensed emission rates of the front and / or back processes; sensed layer formation rates of the front and / or back processes; and operating points (e.g., operating conditions) of the front and / or back processes.

[0089] In general, the release rate and layering rate can be related to one another, for example, via system-specific and / or material-specific factors that can be predetermined. In rare cases, for example, when the release rate is measured at a location on the transport path, the release rate and layering rate can be equal.

[0090] For example, the determination of the actual state of the coating result (e.g., by a model) can be based on an indication of which sub-process of the coating process was interrupted. In that case, for example, the layer stack formed by this sub-process can be set as an invariant according to the actual state determined at the time the sub-process was interrupted. More generally, the model parameters of the layer stack can be set as variables if coating materials are also added to it.

[0091] It can be understood that, instead of or in addition to the operating conditions described above, any other operating parameters can be changed according to specifications to implement process differences. For example, the rate at which the layer-forming material is released (also referred to as the release rate) can be changed as an operating parameter according to specifications. For example, the shutter that blocks the layer-forming material (also referred to as the release rate) can be shifted as an operating parameter according to specifications.

[0092] In an exemplary implementation, a stratification difference (e.g., a sense) is determined, and a model is initialized based on the process difference with the reference time difference and the stratification difference. For example, the actual results determined by the model are based on the stratification rate and the reference time difference of each sub-process.

[0093] In an exemplary operating example, the coating of the front and back surfaces is initiated with a slight time delay, e.g., about 5 to 10 seconds, either front or back first. The coating parameters are selected as follows: The coating speed on the side where coating starts first is set to be equal to or greater than the coating speed on the other side. The time offset (reference time difference) is set so that the layer thickness of the front layer is greater than the layer thickness of the rear layer as far as it is sputtered. - During the coating process, the optical spectrum is continuously recorded with a broadband spectrometer and is given a timestamp of the recording. A model is used to fit the recorded spectrum to the current coating thickness at the time of recording (also referred to as the actual coating thickness). The following applies: In the first fitting (also referred to as equalization calculation), the thickness obtained from the expected coating speed and time is used as the starting point for the fitting. From the fitted thickness, the current coating speed (also known as the actual coating speed) is then calculated. This serves as the basis for further calculations and for determining the switch-off time; As long as the coating is applied on both sides, the two coating thicknesses are fitted simultaneously. The range of possible coating thicknesses is limited during fitting. The maximum allowable coating thickness on the back side is set smaller than the minimum allowable coating thickness on the front side; If the coating is applied on only one side, only this side is fitted. The final value determined is used for the coating thickness on the other side.

[0094] This means that double-sided coating is possible almost simultaneously, even when the front and back coating systems are identical, with control by an optical monitoring system. Even when the front and back coating components are perfectly symmetrically positioned, only one sensor is needed due to the broadband spectrum. As a result, system throughput can be increased. Simultaneous sputtering on the substrate also reduces substrate bending, since the same layer tension is generated on the front and back surfaces.

[0095] Below are described various examples related to those described above and shown in the figures.

[0096] Example 1 is a (e.g., computer-implemented) method comprising: determining an actual state (also referred to as actual result) of a result of a double-sided coating process in which a first layer stack is formed on the front side of a substrate and a second layer stack is formed on the back side of the substrate based on a model implementing a correlation (e.g., mapping) between the result (e.g., its state) and a spectral response (e.g., its state) of the result, and the actual state (also referred to as actual spectral response), an indicator of a difference between a first sub-process of the coating process in which the first layer stack is formed and a simultaneous second sub-process of the coating process in which the second layer stack is formed; and driving the coating process based on the actual state of the result.

[0097] Example 2 is a method according to Example 1, wherein the coating process is controlled according to a specification, preferably representing a target state of the result (also referred to as a target result), e.g., the control of the coating process is based on a comparison of the specification with the actual state of the result (e.g., a result of the comparison).

[0098] Example 3 is a process according to example 2, wherein the first layer stack and the second layer stack have a common structure according to the target state.

[0099] Example 4 is the method according to Example 2 or 3, wherein the first layer stack and the second layer stack according to the target state match in one or more of the following: spatial sequence of layers of different chemical composition, chemical composition of one or more layers, number of layers of different chemical composition, total thickness, and spectral response.

[0100] Example 5 is a method according to any one of Examples 1 to 4, further comprising driving a measurement unit to sense the actual state of the spectral response.

[0101] Example 6 is a method according to any one of Examples 1 to 5, wherein the difference between the first sub-process and the second sub-process results in a difference between the first layer stack and the second layer stack with respect to a rate at which the layer thickness changes (e.g., a layer formation rate) and / or a time at which the layer thickness reaches a target state (also referred to as a target layer thickness).

[0102] Example 7 is the method according to any one of Examples 1 to 6, wherein the difference between the first sub-process and the second sub-process comprises a difference in timing at which an operating point (e.g., operating state) is changed according to a predetermined determination, and / or a difference in the rate at which coating material is delivered (e.g., released, e.g., towards a substrate) (e.g., release rate).

[0103] Example 8 is the method according to any one of Examples 1 to 7, wherein the controlling comprises starting, suspending, resuming, and / or terminating the first sub-process and the second sub-process with a time offset relative to one another, the time offset preferably being based on the actual state of the result, and / or a difference between first sub-processes preferably being based on or including the time offset.

[0104] Example 9 is the method according to any one of Examples 1 to 8, wherein the controlling comprises controlling one or more operators configured to affect the coating process in response to being controlled, e.g., a first operator among the operators configured to affect the first sub-process in response to being controlled, and / or a second operator among the operators configured to affect the second sub-process in response to being controlled.

[0105] Example 10 is the method according to any one of Examples 1 to 9, wherein determining the actual state of the result comprises setting the model to be at least partially invariant for the first layer stack when the first coating process is interrupted and / or for the second layer stack when the second coating process is interrupted.

[0106] Example 11 is the method according to any one of Examples 1 to 10, wherein the spectral response comprises a transmission spectrum and / or the spectral response is determined by ellipsometry.

[0107] Example 12 is a method according to any one of Examples 1 to 11, wherein the model is initialized based on the specification.

[0108] Example 13 is a method according to any one of Examples 1 to 12, wherein the first layer stack and the second layer stack each comprise or at least comprise one or more dielectric and / or optically transmissive (e.g., transparent or translucent) materials (also referred to as layer-forming materials).

[0109] Example 14 is the method according to any one of Examples 1 to 13, wherein the first layer stack and the second layer stack each comprise or at least comprise one or more ceramics.

[0110] Example 15 is the method according to any one of Examples 1 to 14, wherein the controlling of the coating process is carried out according to a cycle, the cycle having a first stage in which the second sub-process is started (e.g., resumed) after the first sub-process with a time delay, a second stage in which the first sub-process and the second sub-process are carried out simultaneously, preferably simultaneously in the coating material provided thereby, a third stage in which the first sub-process is started (e.g., the second stage in which the first sub-process and the second sub-process are carried out simultaneously, preferably simultaneously in the coating material provided thereby), and a third stage in which the first sub-process is interrupted (e.g., terminated) before the second sub-process with a time delay, and the cycle includes varying the coating material provided by the first sub-process and the second sub-process.

[0111] Example 16 is a computer program product having instructions stored on a computer-readable medium, the computer program being configured, when executed by a processor, to cause the processor to perform a method according to any one of Examples 1 to 15.

[0112] Example 17 is a computer-readable medium storing instructions configured, when executed by a processor, to cause the processor to perform a method according to any one of Examples 1-15.

[0113] Example 18 is a control device having one or more processors configured to perform a method according to any one of Examples 1 to 15.

[0114] Example 15 is a processing apparatus comprising a control device according to Example 14, at least one (i.e., one or more) first coating material source configured to perform the first sub-process, and at least one (i.e., one or more) second coating material source adapted to perform the second sub-process, wherein the control device is adapted to drive the at least one first coating material source and the at least one second coating material source (to drive the coating process) based on the actual state of the result, and optionally further comprising a transport device for transporting the substrate along a transport path arranged between the at least one first coating material source and the at least one second coating material source, and / or a vacuum chamber in which the transport path is arranged.

Claims

1. The actual state resulting from a double-sided coating process in which a first layer stack is formed on the front side of a substrate and a second layer stack is formed on the back side of said substrate is represented by: a model that performs a correlation between the results and the spectral response of the results; and the actual state of said spectral response; an indication of a difference between a first sub-process of the coating process in which the first layer stack is formed and a simultaneous second sub-process of the coating process in which the second layer stack is formed; and controlling the coating process based on the actual state of the results; and A method having the following.

2. The method of claim 1 , wherein controlling the coating process is in accordance with a specification that represents a target state for the result.

3. The method of claim 2 , wherein the first layer stack and the second layer stack according to the target state have a common structure.

4. The first layer stack and the second layer stack according to the target state are spatial sequence of layers of different chemical composition, the chemical composition of one or more layers; the number of layers of different chemical composition, Total thickness, Spectral response, The method of claim 2 , wherein the match is in one or more of:

5. The difference between the first sub-process and the second sub-process is: the rate at which the layer thickness changes, and / or When the layer thickness reaches the target state, The method of claim 1 , wherein a difference between the first layer stack and the second layer stack is created with respect to:

6. The difference between the first sub-process and the second sub-process is: The time difference between when the operating parameters are changed according to the specifications, and / or the difference in the rate at which the coating material is fed; 2. The method of claim 1, comprising:

7. the controlling includes starting, suspending, resuming, and / or terminating the first sub-process and the second sub-process with a time offset relative to one another; the time offset is based on the actual state of the result; The method of claim 1.

8. The method of claim 1 , wherein the spectral response comprises a transmission spectrum or a reflection spectrum, and / or the spectral response is determined by ellipsometry.

9. The controlling of the coating process is performed according to a cycle, the cycle comprising: a first stage in which the second sub-process is initiated after the first sub-process with a time delay; the first sub-process and the second sub-process have a second stage carried out simultaneously on the coating material provided thereby; a third step in which the first sub-process is interrupted before the second sub-process with a time delay; The method of claim 1.

10. A computer program having instructions stored on a computer readable medium, the computer program being arranged, when executed by a processor, to cause the processor to carry out a method according to any one of claims 1 to 9.

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

12. A control device having one or more processors adapted to carry out the method of any one of claims 1 to 9.

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