Method for controlling the magnetic flux distribution of an evaporation source material, detector for measuring electromagnetic radiation reflected from the source surface, and system for thermal evaporation using electromagnetic radiation

Abstract

The present invention relates to a method for controlling the magnetic flux distribution (30) of evaporation source material (20) in a system (10) for thermal evaporation using electromagnetic radiation (120), wherein the system (10) comprises: an electromagnetic radiation source (110) for providing electromagnetic radiation (120); a vacuum chamber (12) containing a reactive atmosphere (16); and a detector (40) for measuring the electromagnetic radiation (120), wherein the source material (20) and the target material (18) to be coated are arranged in the vacuum chamber (12), and the radiation source is arranged such that its electromagnetic radiation (120) impinges on the source surface (22) of the source material (20) at an angle, preferably at an angle of 45°, so as to thermally evaporate and / or sublime the source material (20) below the plasma threshold, and wherein the detector (40) for measuring the electromagnetic radiation (120) is arranged such that the electromagnetic radiation (120) reflected on the source surface (22) reaches the detector (40). Furthermore, the present invention relates to a detector (40) for measuring the electromagnetic radiation (120), which detector (40) is preferably suitable for the method according to the present invention, and the present invention also relates to a system (10) for thermal evaporation using electromagnetic radiation (120), which system is suitable for the method according to the present invention.

Description

Technical Field

[0001] The present invention relates to a method for controlling the flux distribution of evaporation source material in a system for thermal evaporation using electromagnetic radiation, wherein the system comprises: an electromagnetic radiation source for providing electromagnetic radiation; a vacuum chamber containing a reactive atmosphere; and a detector for measuring the electromagnetic radiation, wherein the source material and the target material to be coated are arranged in the vacuum chamber, and the radiation source is arranged such that its electromagnetic radiation impinges on the source surface of the source material at an angle (preferably at an angle of 45°) so as to thermally evaporate and / or sublime the source material below the plasma threshold, and wherein the detector for measuring the electromagnetic radiation is arranged such that the electromagnetic radiation reflected on the source surface reaches the detector.

[0002] Furthermore, the present invention relates to a detector for measuring the electromagnetic radiation reflected on the source surface, comprising a sensor element having an absorber, the absorber comprising an absorption surface for at least partially absorbing the electromagnetic radiation, wherein the sensor element further comprises a heat sensing element for measuring the temperature of the absorber in order to detect the absolute temperature and / or temperature change caused in the absorber by the absorbed electromagnetic radiation.

[0003] In addition, the present invention relates to a system for thermal evaporation using electromagnetic radiation, comprising: an electromagnetic radiation source for providing electromagnetic radiation; a vacuum chamber containing a reactive atmosphere; and a detector for measuring the electromagnetic radiation, wherein the source material and the target material to be coated are arranged in the vacuum chamber, and the electromagnetic radiation source is arranged such that its electromagnetic radiation impinges on the source surface of the source material at an angle (preferably at an angle of 45°) so as to thermally evaporate and / or sublime the source material below the plasma threshold, wherein the detector for measuring the electromagnetic radiation is arranged such that the electromagnetic radiation reflected on the source surface reaches the main detector. Background Art

[0004] It is known to use electromagnetic radiation, in particular lasers having wavelengths in the visible, infrared or ultraviolet range, to evaporate source materials. Such laser evaporation systems allow the deposition of thin films of material at low pressure by heating the center of a source material block with a continuous wave laser from the front. For example, silicon melts at the temperature required to achieve the desired flux of the evaporated material, thereby forming a molten pool within the solid portion of the same source material. Thus, solid Si forms a crucible for the liquid Si, thereby allowing very high heating and cooling rates due to the absence of a thermal expansion mismatch between the source material and the crucible. At the same time, any contamination of the source material by different crucible materials is avoided. Alternatively, a crucible made of a material different from the material to be evaporated can also be used.

[0005] However, as the source material is depleted by the impinging electromagnetic radiation, the source surface changes its shape as the melt pool, for example, develops into a concave shape and / or the sublimation spots dig deeper and deeper into the source material. Thus, since the shape of the source surface directly affects the flux distribution and evaporation rate of the evaporated material, the aforementioned flux distribution and evaporation rate of the evaporated material are inherently unstable.

[0006] Generally, two main cases can be distinguished. In the case of local concave sublimation or evaporation, a depression is formed under the spot or electromagnetic radiation because the sublimation or evaporation rate is maximum at the center of the spot due to the radial intensity attenuation of the electromagnetic radiation within the beam and the thermal gradient away from the intensity maximum. Moving outwards from the deepest point of this depression, the surface elements are inclined inwards towards the symmetry axis of the source, thereby contributing more to the center of the flux distribution. This focusing of the flux distribution would even be advantageous, especially when coating a small sample at a relatively large distance. However, once the depression in the source surface becomes too deep, the evaporation or sublimation from the sidewall surface elements is inclined too much, and the flux distribution defocuses again. In addition, the steep sidewalls may shield some parts of the material to be coated, resulting in strong thickness non-uniformities.

[0007] A locally convex sublimation or evaporation surface is the second main case. Here, the surface elements away from the symmetry axis of the source are inclined outwards, directly resulting in a more diffused flux distribution, in which more material is directed beside the sample compared to the case of a flat surface. This defocused flux distribution can lead to a reduced growth rate on the target substrate, whereby the amount of source material that misses the target by sublimation or evaporation is greater than in the case of a flat source surface.

[0008] Generally, the known method to overcome this problem is to move the electromagnetic radiation spot over the source material to obtain a more uniform distribution of the energy deposition and thus a more uniform distribution of the flux distribution of the evaporated source material. However, for providing an actual active control of the flux distribution, a reliable detection of the surface curvature under the electromagnetic radiation spot is required. Direct observation of the source surface with a camera is hindered by any window facing the source surface due to the rapid coating and thus the evaporation or sublimation flux. Summary of the Invention

[0009] In view of the above, it is an object of the present invention to provide an improved method for controlling the flux distribution of an evaporating source material, an improved detector for measuring electromagnetic radiation reflected from the source surface, and an improved system for thermal evaporation using electromagnetic radiation that do not have the above-mentioned disadvantages of the prior art. In particular, it is an object of the present invention to provide a method, a detector, and a system that allow controlling the flux distribution of the evaporating source material in a system for thermal evaporation using electromagnetic radiation in a particularly easy and low-cost manner, wherein preferably, the flux distribution can be adjusted separately for spatial variations with respect to shape, size, and direction, especially in a closed-loop control.

[0010] This object is achieved by the corresponding independent patent claims. In particular, this object is achieved by the method according to claim 1, the detector according to claim 11, and the system according to claim 29. The dependent claims describe preferred embodiments of the invention. The details and advantages described with respect to the method according to the first aspect of the invention also relate to the detector according to the second aspect of the invention and the system according to the third aspect of the invention, and vice versa if of technical significance.

[0011] According to a first aspect of the invention, this object is achieved by a method for controlling the flux distribution of evaporation source material in a system for thermal evaporation using electromagnetic radiation, wherein the system comprises: an electromagnetic radiation source for providing electromagnetic radiation; a vacuum chamber containing a reactive atmosphere; and a detector for measuring the electromagnetic radiation, wherein the source material and the target material to be coated are arranged in the vacuum chamber, and the radiation source is arranged such that its electromagnetic radiation impinges on the source surface of the source material at an angle, preferably at an angle of 45°, to thermally evaporate and / or sublime the source material below the plasma threshold, and wherein the detector for measuring the electromagnetic radiation is arranged such that the electromagnetic radiation reflected on the source surface reaches the detector.

[0012] The method according to the invention comprises the following steps:

[0013] a) Defining a desired distribution of the flux of the source material evaporated from the source surface and an impingement distribution of the electromagnetic radiation required for the desired distribution;

[0014] b) Determining an expected distribution of the electromagnetic radiation reflected on the source surface based on the desired distribution and the impingement distribution of step a);

[0015] c) Providing electromagnetic radiation by the electromagnetic radiation source with the required impingement distribution defined in step a);

[0016] d) Measuring the electromagnetic radiation reflected on the source surface by the detector;

[0017] e) Determining a measured distribution of the electromagnetic radiation reflected on the source surface based on the measurement data of step d);

[0018] f) Determining the difference between the expected distribution determined in step b) and the measured distribution determined in step e);

[0019] g) Re - determining the required impingement distribution of the electromagnetic radiation provided by the electromagnetic radiation source to minimize the difference determined in step f); and

[0020] h) Providing electromagnetic radiation by the electromagnetic radiation source with the required impingement distribution re - determined in step g).

[0021] The method according to the invention can be used in or by a system for thermally evaporating a source material using electromagnetic radiation. Hereinafter, the term "evaporation" also includes any sublimation process, even if not explicitly mentioned. The evaporated source material can preferably be used to coat a target material, for example in the form of a thin film. The source material and the target material are placed in a vacuum chamber of the system, wherein the vacuum chamber contains a reaction atmosphere suitable for the desired coating of the target material. For example, the reaction atmosphere can be provided as a vacuum or contain the required reaction gases (such as oxygen and / or nitrogen).

[0022] For the evaporation process, an electromagnetic radiation source provides electromagnetic radiation which is introduced into the vacuum chamber and impinges on the source surface of the source material. The energy deposition of the electromagnetic radiation evaporates or sublimates the source material. The energy deposition is chosen such that the plasma threshold of the source material is not reached. Thus, a pure thermal evaporation of the source material can be provided, in particular without the formation of any plasma. By impinging at an angle, preferably at an angle of 45°, conflicts between the path of the electromagnetic radiation in the vacuum chamber and other structures in the vacuum chamber (such as source and / or target holding elements) can be avoided.

[0023] Only a part of the electromagnetic radiation impinging on the source surface is absorbed by the source material and used for the evaporation process. The remaining part of the electromagnetic radiation is reflected on the source surface. In other words, the absorbed part and the reflected part of the electromagnetic radiation are directly related to each other. In particular, the reflected part of the electromagnetic radiation carries information about the shape and form of the surface, since for example the flat, concave and convex parts of the surface reflect the impinging electromagnetic radiation differently. Thus, the shape and form of the surface are imprinted on the reflected electromagnetic radiation. Therefore, by detecting the electromagnetic radiation reflected on the source surface, the actual shape and form of the source surface can be inferred. For detecting the reflected electromagnetic radiation, a detector is used in the method according to the invention, which is appropriately positioned in the vacuum chamber in the path of the reflected electromagnetic radiation.

[0024] As described above, the measured reflected electromagnetic radiation allows the inference of the actual shape and form of the source surface. Thus, the actual distribution of the flux of the evaporated or sublimated source material can also be determined. Since the desired flux distribution is known, it can be determined how the impinging electromagnetic radiation must be formed when impinging on the actually existing source surface to produce the desired flux distribution.

[0025] Hereinafter, the individual steps of the method according to the invention are described in detail.

[0026] In a first step a) of the method according to the invention, the desired distribution of the flux of the source material evaporated from the source surface is defined. In most cases, the desired flux distribution will be such that a uniform coating of the target can be achieved. However, different, especially spatially related, desired flux distributions can also provide a coating on a target with a position-dependent thickness.

[0027] In addition, step a) further includes defining the impact distribution of the electromagnetic radiation. The impact distribution is defined such that a desired distribution of the magnetic flux of the evaporation source material can be provided. In addition to the desired magnetic flux distribution, during the definition of the impact distribution of the electromagnetic radiation, the initial form and shape of the source surface, which are mostly flat and / or circular, can preferably also be taken into account.

[0028] In the next step b) of the method according to the invention, based on the result of step a), the expected distribution of the electromagnetic radiation reflected on the source surface is determined. In particular, the desired distribution and the impact distribution are used to determine the expected distribution. Similar to step a), during the determination of the expected distribution of the electromagnetic radiation, the initial form and shape of the source surface can also be additionally taken into account.

[0029] In the subsequent step c) of the method according to the invention, electromagnetic radiation is provided by the electromagnetic radiation source with the required impact distribution defined in step a). The electromagnetic radiation source can be directly attached to the vacuum chamber. Alternatively, the electromagnetic radiation source can be positioned at a distance from the vacuum chamber, even in a different room or building, and the electromagnetic radiation can be guided to the vacuum chamber through a suitable guiding element (such as an optical fiber). Thus, the electromagnetic radiation impacts on the source surface of the source material with the required impact distribution and causes the source material to thermally evaporate or sublime below the plasma threshold.

[0030] At the same time, the part of the electromagnetic radiation not absorbed by the source material is reflected on the source surface. In the subsequent step d) of the method according to the invention, the reflected electromagnetic radiation is measured by a detector of the system. For this purpose, the detector is appropriately positioned inside the vacuum chamber.

[0031] In the subsequent step e), the measurement data obtained in step d) of the method according to the invention is analyzed. In particular, the measured distribution of the electromagnetic radiation is determined based on the measurement in step d).

[0032] The information about the measured distribution obtained in step e) is used in the next step f) to determine the difference between the expected distribution determined in step b) and the measured distribution determined in step e). In other words, after performing step f), information on whether the actual measured distribution meets the expected distribution is generated. The greater the difference between these two distributions, the greater the difference between the actual magnetic flux distribution of the evaporated source material and the desired distribution defined in step a) according to the invention.

[0033] Based on the findings in step f), in the subsequent step g) of the method according to the invention, the required impact distribution is re-determined. In particular, the measured distribution and its difference from the expected distribution allow obtaining information about the actual shape and form of the source surface. Therefore, based on this, the determination of the required impact distribution of the electromagnetic radiation can be improved to achieve the desired distribution of the magnetic flux of the evaporation source material. Thereby, the difference determined in step f) should be automatically minimized.

[0034] In the final step h) of the method according to the invention, electromagnetic radiation is provided by an electromagnetic radiation source with the required impact distribution re - determined in step g). Thus, the electromagnetic radiation impacts on the source surface of the source material with the re - determined required impact distribution, and causes the source material to thermally evaporate or sublime below the plasma threshold. Since the actual shape and form of the source surface are taken into account, the matching between the desired distribution and the actually existing distribution of the flux of the evaporating source material is improved.

[0035] In summary, the method according to the invention described above allows for the active adjustment of the flux distribution of the evaporating or subliming source material during the operation of the corresponding evaporation system based on actual measurements. Thus, the flux distribution can be controlled. Consequently, the coating of the target material can also be improved.

[0036] Furthermore, the method according to the invention may include that the desired distribution defined in step a) includes a time - dependence. The time - dependence of the present invention can be applied, for example, to the spatial shape and / or orientation of the desired distribution. Alternatively or additionally, the intensity of the desired distribution can also vary with time. Thus, the coating of the target can be controlled in a very specific manner, including, for example, the spatial thickness variation of the coating of the target material. Preferably, since the desired distribution is time - dependent, the remaining steps of the method according to the invention are adjusted accordingly, that is, for example, the required distribution and the expected distribution also include the adjusted time - dependence, and the measurements, comparisons, and re - determinations in steps d), f), and g) are respectively repeated to follow this time - dependence.

[0037] In addition, the method according to the invention may be characterized in that the expected distribution in step b) is determined by calculating the expected distribution and / or experimentally measuring the expected distribution and / or empirically estimating the expected distribution. This list is not exhaustive, and in particular, different methods for determining the expected distribution can also be applied if possible and have technical significance. Calculating the expected distribution is based on all accessible information, such as the desired distribution and the required distribution. Empirical estimation is based on general assumptions, such as the assumed form and shape of the source surface. Preferably, a combination of calculation and estimation is applied. By experimentally measuring the expected distribution, a very accurate expected distribution can be provided. The disadvantage of this method is that it requires time and effort for additional experimental measurements.

[0038] Preferably, the method according to the present invention may include: repeatedly performing steps d) to h). The repetition rate may be stable, such as 10 Hz or even higher, until the continuous repetition of steps d) to h). Moreover, an appropriate repetition rate may be adopted, whereby the corresponding repetition can be triggered manually and / or when the parameters of the system exceed or fall below a threshold, for example, by depositing energy into the detector by electromagnetic radiation reflected on the source surface. The repetition of steps d) to h) provides the possibility of ensuring the provision of a desired distribution over an extended period of time. In particular, the repetition allows for closed-loop control to provide a flux of evaporated or sublimated source material in a desired distribution.

[0039] Furthermore, the method according to the present invention may include: using electromagnetic radiation light, particularly a laser, having a wavelength between 100 nm and 1400 nm. The light, particularly the laser, is easy to provide, and in particular, it can be easily guided from a light source separated from the vacuum chamber to the vacuum chamber. In particular, the light can also have a wide range of energy densities, so it can be easily provided for the provision of electromagnetic radiation for evaporation below the plasma threshold of a specific source material.

[0040] According to another embodiment, the method according to the present invention may be characterized in that, in step e) and / or f), the response function of the detector is considered. The response function of the detector has a direct impact on the measurement of the reflected electromagnetic radiation. For example, the solid angle covered by the detector limits the measured signal. Moreover, the dead time of the detector and the energy correlation of, for example, the detector sensitivity can affect the actual measurement. Therefore, by considering the response function in step e) and / or step f), the influence of the detector settings on the measurement distribution can be considered at least partially, preferably completely.

[0041] Additionally or alternatively, the method according to the present invention may include: in step f), using the size and / or shape of the expected distribution and the measured distribution to determine the difference. As described above, changes in the shape and / or form of the source surface affect the distribution of the reflected electromagnetic radiation. In particular, the concave and convex portions of the source surface reflect the incident electromagnetic radiation differently, and in particular, they disperse the incident electromagnetic radiation. Thus, the shape and form of the surface are imprinted on the shape and form of the reflected electromagnetic radiation. Therefore, by detecting the size and / or shape of the electromagnetic radiation reflected on the source, the information on the shape and / or form of the source surface imprinted on the reflected electromagnetic radiation can be detected particularly easily.

[0042] Furthermore, the method according to the invention may be characterized in that the electromagnetic radiation source comprises two or more emitter parts, whereby, in steps c) and h), each emitter part provides electromagnetic radiation impinging on the source surface, and wherein the system accordingly comprises two or more detectors, each detector being arranged to measure the electromagnetic radiation provided by one emitter part and reflected on the source surface. In other words, according to this embodiment, the source surface is irradiated by two separate electromagnetic radiation beams, whereby each beam is monitored by a separate dedicated detector. Each pair of emitter part and the assigned detector can perform the emission and measurement elements of the method according to the invention. In summary, a more uniform distribution of the electromagnetic radiation impinging on the source surface can be provided, and subsequently also an active control of such a distribution for an electromagnetic radiation source with a single emitter as described above can be provided. This also improves the smoothness of the desired distribution that can be provided.

[0043] Additionally, the method according to the invention can be improved by the respective electromagnetic radiation provided by two or more emitter parts impinging radially symmetrically on the source surface. In other words, the emitter parts are evenly distributed around the source surface. Thus, if the impingement distributions of two or more emitter parts are equal, the combined impingement distribution is also rotationally symmetric. In particular, thus, effects such as the tilting and / or skewing of the molten source material in the direction of the impinging electromagnetic radiation can be prevented.

[0044] A further improved embodiment of the method according to the invention may be characterized in that two or more emitter parts provide electromagnetic radiation with an adjustable power density and / or shape and / or size. As described above, in some cases, it is advantageous to provide a desired distribution including a spatial distribution on the source surface. This can be easily set with two or more emitter parts, whereby each emitter part can emit electromagnetic radiation, the respective power density, shape and / or size of which can be individually changed. In summary, this allows a desired distribution of the source material flux evaporated from the source surface according to the position on the source surface.

[0045] According to a second aspect of the invention, this object is achieved by a detector for measuring electromagnetic radiation reflected on a source surface, the detector comprising a sensor element having an absorber, the absorber comprising an absorption surface for at least partially absorbing the electromagnetic radiation, wherein the sensor element further comprises a heat sensing element for measuring the temperature of the absorber in order to detect the absolute temperature and / or temperature change caused in the absorber by the absorbed electromagnetic radiation, wherein the heat sensing element comprises a temperature sensor arranged in a hole in the absorber, in particular a thermocouple element, wherein the hole terminates inside the absorber, preferably in the vicinity of the absorption surface.

[0046] The detector according to the invention can be used in a system for thermal evaporation using electromagnetic radiation. In particular, such a detector can be used to measure electromagnetic radiation, for example, electromagnetic radiation reflected on the source surface of the source material.

[0047] The electromagnetic radiation to be measured impinges on the absorber, in particular on the absorption surface, and is at least partially absorbed by the absorption surface. In other words, at least a part of the energy of the electromagnetic radiation is deposited in the absorber. Therefore, measuring and monitoring the temperature of the absorber respectively allows determining the energy deposited in the absorber, and thus determining the amount of electromagnetic radiation impinging on the absorption surface.

[0048] The absorption surface faces at least partially towards the source surface. Therefore, the absorption surface is coated with the evaporated or sublimated source material of the source. After a sufficient long deposition, the detector thus has the same (which also means constant) absorption rate and reflectivity as the source.

[0049] The absorption surface can be aligned, for example, perpendicular to the assumed impinging direction of the electromagnetic radiation to be measured. Since only a part of the impinging electromagnetic radiation will be absorbed, the remaining part will be reflected back in the same direction. In a system for thermal evaporation in which the detector according to the invention is used to measure the electromagnetic radiation reflected on the source surface, the electromagnetic radiation reflected on such an absorption surface is guided back onto the source surface and can be used for a second thermal evaporation.

[0050] However, the subsequent second reflection on the source surface guides the electromagnetic radiation back to the electromagnetic radiation source and can cause interference. An embodiment of the absorption surface having two flat portions arranged adjacent to each other at an angle slightly less than 90° (e.g., 89°) can solve this problem. The electromagnetic radiation can still be reflected back onto the source surface, but not exactly in the same direction, and thus misses the electromagnetic radiation source. Additionally, since the electromagnetic radiation impinging on the double absorption surface is reflected twice, the absorption of the absorption surface for the impinging electromagnetic radiation is also doubled. Thereby, the deposition of energy into the absorber can be increased and thus the measurement accuracy can be improved.

[0051] To measure and / or monitor the amount of energy deposited in the absorber by the impinging electromagnetic radiation, the absolute temperature and / or the temperature change of the absorber can be measured and / or monitored. In the detector according to the invention, this measurement is performed by using a temperature sensor arranged in a hole near the absorption surface within the absorber.

[0052] This hole allows the temperature sensor to be arranged near the absorption surface, thereby improving the accuracy of temperature measurement. With the temperature sensor within the absorber, the actual temperature of the absorber and / or the change in this temperature can be directly measured. Thus, the absolute value of the energy deposition into the absorber caused by the absorbed electromagnetic radiation can be determined. In particular, based on the measurement of, for example, the electromagnetic radiation reflected on the source surface by the detector according to the invention, the measurement distribution of the electromagnetic radiation reflected on the source surface can be inferred and subsequently controlled, and subsequently the corresponding matching of the actual distribution of the evaporation source material with the desired distribution of the evaporation source material can be inferred and subsequently controlled.

[0053] Preferably, the detector according to the invention comprises: The detector can be used in the method according to the first aspect of the invention. Thus, all the features and advantages described in detail with respect to the method according to the first aspect of the invention can also be provided by the detector according to the second aspect of the invention, which is used to carry out the method according to the first aspect of the invention.

[0054] Additionally, the detector according to the invention may be characterized in that the absorption surface absorbs light having a wavelength between 100 nm and 1400 nm, in particular laser light. As mentioned above, for the method according to the first aspect of the invention, light, in particular laser light, is suitable for the evaporation and / or sublimation of a wide range of viable source materials. By providing an absorption surface capable of absorbing light, the detector according to the invention can be adapted to this particular electromagnetic radiation. This adaptation may include, for example, a suitable material selected for the absorber on which the absorption surface is arranged. Additionally or alternatively, a coating for the adaptive selection of the absorption surface for enhancing light absorption may also be used.

[0055] In another embodiment of the detector according to the invention, the absorber comprises a cooling system for the active cooling of the absorber, whereby the cooling system comprises at least one cooling pipe within the absorber for allowing a coolant, preferably water, to flow through the absorber. The cooling pipes of the cooling system pass through the absorber and allow the coolant to flow through the absorber. The coolant may be a fluid, preferably water is used as the coolant. By flowing through the absorber, the coolant cools the absorber. Preferably, the cooling system maintains the absorber at a constant temperature. Thus, the absorber does not change its temperature and thus maintains its ability to detect the impinging electromagnetic radiation. Further, the coolant flowing through the cooling pipes in the absorber preferably absorbs any energy deposited into the absorber by the impinging electromagnetic radiation. Thus, the temperature of the coolant changes according to the amount of absorbed energy.

[0056] Thus, the detector according to the present invention can be further improved in the following manner: The thermal sensing element includes a flow sensor that measures the flow rate of the coolant through the cooling pipes in the absorber and a temperature sensor that measures the absolute temperature and / or temperature change of the coolant caused by the coolant flowing through the cooling pipes in the absorber. In order to measure the temperature and / or temperature change of the coolant and thus the temperature and / or temperature change of the absorber, the sensing element of the detector according to the present invention includes two different types of sensors, namely a flow sensor and a temperature sensor. In particular, the flow sensor measures the flow rate of the coolant flowing through the cooling pipes. The temperature sensor measures the temperature of the coolant. In particular, the temperature of the coolant is measured at least at the outlet of the cooling pipes, and preferably also at the inlet of the cooling pipes. The outlet temperature allows the detection of temperature changes over time, provided that the coolant is supplied at a constant temperature at the inlet. By additionally measuring the inlet temperature of the coolant, this measurement of the relative temperature change can be improved. In particular, by combining the temperature measurement with the above-mentioned flow measurement, the absolute value of the energy deposition into the absorber caused by the absorbed electromagnetic radiation can be determined.

[0057] The additionally measured temperature value can be used to check the measurement of the temperature sensor arranged in the hole and / or improve the overall accuracy of the temperature measurement. Additionally, if the temperature measurement based on the temperature sensor in the hole fails or is completely lost, the temperature of the absorber can still be measured and thus the energy deposited into the absorber by the electromagnetic radiation can be measured.

[0058] Furthermore, the detector according to the present invention can preferably include: The absorber includes a metal, in particular copper or aluminum, and is particularly composed of them. The metal as the absorber material offers several advantages. First, metals, in particular copper and aluminum, have high thermal conductivity. The detector according to the present invention is designed as a bolometer that absorbs the incident electromagnetic radiation and includes a sensor element that measures the temperature and / or temperature change caused by this absorption. Materials with high thermal conductivity are particularly suitable for such bolometers. Further, metals are materials that are compatible with use under ultra-high vacuum conditions. Thus, contamination of the ultra-high vacuum (such as a reactive atmosphere) caused by the detector according to the present invention can be avoided, and vice versa.

[0059] In a further preferred embodiment of the detector according to the invention, the absorber surrounds a hollow absorption volume at one end, whereby the inner wall of the absorption volume forms the absorption surface, and wherein the absorption volume includes an absorption aperture, whereby the absorption aperture can be aligned with the assumed and / or determined impact direction of the electromagnetic radiation to be measured. As described above, in most cases, the absorption surface also only absorbs a part of the impinging electromagnetic radiation, at least a part of the electromagnetic radiation impinging directly on the detector. In this preferred embodiment of the detector according to the invention, the absorption surface is provided as the inner wall of the hollow absorption volume. The electromagnetic radiation impinging on the detector enters the absorption volume through the absorption aperture. Inside the absorption volume, the electromagnetic radiation impinges on the absorption surface and is partially absorbed and partially reflected. Since this reflection occurs in an absorption volume which is preferably large relative to the absorption aperture, it is very likely that the reflected electromagnetic radiation misses the absorption aperture and impinges again on the inner wall of the absorption volume, in other words, on another part of the absorption surface. In an ideal case, this process itself is repeated until the impinging electromagnetic radiation is completely or at least substantially completely absorbed by the absorber. In this case, the energy deposition in the absorber represents the total energy of the impinging electromagnetic radiation. In particular, any coating of the absorption surface with evaporation source material is thus not affected.

[0060] A further improved embodiment of the detector according to the invention can comprise: the absorption surface is partially conical in the absorption volume, wherein the cone of the conical absorption surface faces the absorption aperture. The cone can be shaped as both a protrusion and a recess, whereby, in the protrusion embodiment, the tip of the cone faces the absorption aperture, and in the recess embodiment, the base of the cone faces the absorption aperture. In other words, the impinging electromagnetic radiation passing through the absorption aperture first impinges on the conical part of the absorption surface. When the cone faces the absorption aperture, any electromagnetic radiation reflected on the side of the cone is directed somewhere in the absorption volume and definitely misses the absorption aperture. Thus, the above ideal case of complete absorption of the impinging electromagnetic radiation in the absorption volume can be more easily achieved.

[0061] Furthermore, the detector according to the invention can be improved by inclining the part of the absorption volume forming the edge of the absorption aperture inwards relative to the absorption volume. Similar to the above-mentioned cone opposite the absorption aperture, the inwardly inclined edge surrounding the absorption aperture also helps to ensure that the electromagnetic radiation is reflected back into the absorption volume. Thus, also in this embodiment of the detector according to the invention, the above ideal case of complete absorption of the impinging electromagnetic radiation in the absorption volume can be more easily achieved.

[0062] Preferably, the detector according to the invention comprises a conical part opposite the absorption aperture and an inclined edge surrounding the absorption aperture.

[0063] Another embodiment of the detector according to the invention may be characterized in that the detector comprises an aperture having an aperture opening, wherein the aperture is arranged upstream of the sensor element along the assumed and / or determined impact direction of the electromagnetic radiation to be measured. Such an aperture can contribute to defining a solid angle that can be measured by the detector according to the invention. To enhance the definition of the solid angle, two or more apertures may also be used, which are aligned and stacked upstream along the assumed and / or determined impact direction, respectively. Preferably, the aperture is sized and arranged such that, for example, the source surface irradiated by the electromagnetic radiation source is visible from the viewpoint of the detector, and thus the electromagnetic radiation reflected on the source surface can reach the detector. Additionally, electromagnetic radiation originating from other locations within the vacuum chamber is blocked by the aperture, and thus the overall accuracy of the measurement by the detector according to the invention can be improved.

[0064] In a further improved embodiment of the detector according to the invention, the size of the aperture opening is adapted to the absorber, in particular to the absorption orifice, such that the electromagnetic radiation entering through the aperture opening impinges on the absorption surface of the absorber, in particular through the absorption orifice. In this embodiment, the limitation of the field of view of the aforementioned detector is further improved. Since the aperture opening and the absorber, in particular the absorption orifice, are configured to be adapted to each other, it can be ensured that all the electromagnetic radiation entering through the aperture opening can be recorded by the detector. Thereby, the loss of information can be avoided or at least minimized.

[0065] To further limit and optimize the field of view, a plurality of consecutive apertures may be used. This is particularly useful for strong sources that are close together and need to be measured at a large distance from the source.

[0066] Additionally, the detector according to the invention can be improved in that the detector comprises a shielding element, wherein the shielding element extends between the aperture and the absorber along the assumed impact direction of the electromagnetic radiation to be measured. The shielding element and the aperture together form a volume in front of the detector into which only the electromagnetic radiation entering through the aperture opening can enter. The scattered electromagnetic radiation that completely misses the aperture but would impinge on the absorber is blocked by the shielding element. Thereby, the field of view of the detector can be defined with improved accuracy.

[0067] Furthermore, in another improved embodiment of the detector according to the invention, the shielding element further extends along the absorber along the assumed impact direction of the electromagnetic radiation. However, the electromagnetic radiation impinging on the absorber away from the absorption surface can deposit energy into the absorber, thereby distorting the result measured by the detector. The shielding element that further extends along the absorber covers the absorber and intercepts all the incident electromagnetic radiation. Therefore, the measurement distortion of the detector can be avoided or at least minimized.

[0068] In another preferred embodiment, the detector according to the invention may be characterized in that the detector comprises two or more sensor elements, whereby the two or more sensor elements are adjacent to each other and thermally decoupled. As described above, during evaporation, the source surface may change its spatial shape, in particular the source surface may assume a convex or concave shape. This spatial shape of the source surface also affects the measurement results of the detector, since a part of the reflected electromagnetic radiation simply misses the main detector and / or other parts even focus in the direction of the detector. By providing a detector with two or more sensor elements, a more precise measurement of the distribution of the reflected electromagnetic radiation can be obtained. In particular, even changes in the spatial shape and / or form of the source surface can be detected, since these changes result in detectable differences in the distribution of the reflected electromagnetic radiation measured by the two or more sensor elements. By providing these two or more thermally decoupled sensor elements, independent measurements of the individual sensor elements can be provided. The arrangement of the sensor elements adjacent to each other ensures that the gap between the sensor elements is minimized, in which the reflected electromagnetic radiation escapes the detector.

[0069] Furthermore, the detector according to the invention can be improved in such a way that the two or more sensor elements are arranged in a rotationally symmetric pattern or in rows or matrices in a plane perpendicular to or at least substantially perpendicular to the assumed and / or determined impact direction of the electromagnetic radiation to be measured. The different patterns allow the detector to be adapted to different measurement purposes. For example, the rotationally symmetric pattern allows the identification of focusing problems on the electromagnetic radiation provided by the electromagnetic radiation source, whereby the row arrangement is particularly useful for the spot misalignment between the electromagnetic radiation and the source surface. Matrices, especially when using multiple sensor elements, allow for an even more detailed measurement of the distribution of the electromagnetic radiation reflected on the source surface.

[0070] A further improved embodiment of the detector according to the invention may comprise that, in a plane perpendicular to or at least substantially perpendicular to the assumed and / or determined impact direction of the electromagnetic radiation to be measured, the two or more sensor elements comprise one of the following shapes:

[0071] - rectangular;

[0072] - square;

[0073] - circular;

[0074] - circular ring;

[0075] - circular ring segment.

[0076] This list is not complete and can be extended by additional suitable shapes. In particular, using the above-described arrangement patterns of two or more sensor elements, the shape of the respective sensor elements adaptively selected for the currently applied mode allows for a compact and continuous arrangement of the respective sensor elements without avoiding gaps between the individual sensor elements.

[0077] Furthermore, the detector according to the invention may be characterized in that the detector comprises an arrangement element for arranging the absorber at the vacuum feedthrough. This particularly preferred embodiment of the detector according to the invention allows the detector to be arranged directly in and / or at the vacuum feedthrough of the vacuum chamber. All connections (such as the inlets and outlets of the coolant channels and the electrical connections of the sensor elements) can be accessed from the outside of the vacuum chamber. Inside the vacuum chamber, essentially only the absorber is located, if there are also aperture and / or shielding elements. These elements can be provided in embodiments that can be used for ultra-high vacuum. Thus, mutual damage between the parts of the detector and the reactive atmosphere inside the vacuum chamber can be avoided.

[0078] In a further improved embodiment of the detector according to the invention, the arrangement element comprises a positioning element for changing the position of the absorber relative to the vacuum feedthrough. The possibility of changing the position of the absorber inside the vacuum chamber can be used, for example, to exchange the source material and / or the target material. Thereby, it can be avoided that this exchange process is disturbed by the detector, in particular by the absorber. In particular, after completion of the process, the absorber can be rearranged near the source element to enhance the measuring ability of the detector according to the invention by enlarging the covered solid angle.

[0079] According to a third aspect of the invention, this object is achieved by a system for thermal evaporation using electromagnetic radiation, the system comprising: an electromagnetic radiation source for providing electromagnetic radiation; a vacuum chamber containing a reactive atmosphere; and a main detector for measuring the electromagnetic radiation, wherein the source material and the target material to be coated are arranged in the vacuum chamber, and the electromagnetic radiation source is arranged such that its electromagnetic radiation impinges on the source surface of the source material at an angle, preferably at an angle of 45°, so as to thermally evaporate and / or sublime the source material below the plasma threshold, wherein the main detector for measuring the electromagnetic radiation is arranged such that the electromagnetic radiation reflected on the source surface reaches the main detector, and wherein the system according to the third aspect of the invention is adapted to perform the method according to the first aspect of the invention. Thus, all features and advantages described in detail with respect to the method according to the first aspect of the invention can also be provided by the system according to the third aspect of the invention, which is adapted to perform the method according to the first aspect of the invention.

[0080] Preferably, the system according to the invention can be improved in such a way that at least the main detector is constructed according to the second aspect of the invention, preferably each detector for electromagnetic radiation. In this particular embodiment, all features and advantages described in detail with respect to the detector according to the second aspect of the invention can also be provided by the system according to the third aspect of the invention, which system comprises at least one detector according to the second aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The invention will be further described hereinafter with reference to the illustrated embodiments shown in the drawings. Shown are:

[0082] Figure 1 a system according to the invention;

[0083] Figure 2 a first feasible embodiment of a detector according to the invention;

[0084] Figure 3 an absorber having an absorption volume;

[0085] Figure 4 an embodiment of a detector according to the invention having two sensor elements;

[0086] Figure 5 an arrangement pattern of the sensor elements;

[0087] Figure 6 the magnetic flux of evaporation source material from a flat source surface;

[0088] Figure 7 the magnetic flux of evaporation source material from a recessed source surface;

[0089] Figure 8 the magnetic flux of evaporation source material from a convex source surface;

[0090] Figure 9 the inclination of a molten source material droplet;

[0091] Figure 10 the behavior of a molten droplet under two impinging electromagnetic radiations;

[0092] Figure 11 a feasible arrangement of three radiation emitters; and

[0093] Figure 12 scanning a target by adjusting two impinging electromagnetic radiation beams. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0094] In Figure 1FIG. 0 shows the main components of a system 10 for thermally evaporating a source material 20 using electromagnetic radiation 120 according to the present invention. The source material 20 is arranged within a vacuum chamber 12, whereby the vacuum chamber 12 defines a reaction atmosphere 16. The vacuum chamber 12 itself is only indicated as being adjacent to a vacuum feedthrough 14. According to the invention, an electromagnetic radiation source 110 is arranged at one vacuum feedthrough 14 and a detector 40 is arranged at another.

[0095] During operation of the system 10, the electromagnetic radiation source 110 provides electromagnetic radiation 120 that is directed towards and impinges on a source surface 22 of the source material 20. The source material 20 absorbs a portion of the electromagnetic radiation 120, and thus some of the source material 20 evaporates or sublimes, as Figure 1 indicated by the circular dashed line in FIG. Opposite the source material 20, a target material 18 is arranged. The evaporated source material 20 reaches the target material 18 and forms a coating on the surface of the target material 18.

[0096] The remaining portion of the electromagnetic radiation 120 is reflected from the source surface 20. Since the emission direction of the electromagnetic radiation source 110 and the position and overall orientation of the source surface 22 are known, the detector 40 can be arranged in the assumed and / or determined impact direction 122 of the reflected electromagnetic radiation 120. As has been described for the electromagnetic radiation source 110, the detector, in particular its absorber 52, can also be arranged at the vacuum feedthrough 14 of the vacuum chamber 12.

[0097] According to the invention, the detector 40 serves as a bolometer. The electromagnetic radiation 120 impinges on an absorption surface 60 of the absorber 52 and is at least partially absorbed. As depicted, the absorption surface 60 faces the source surface 22 and is thus also coated with the evaporated source material 20, as Figure 1 indicated in FIG. Thus, after a short build-up time, the absorption surface 60 includes absorption and reflection characteristics that are the same as or at least similar to those of the source surface 22.

[0098] The above-described energy deposition into the absorber 52 causes a temperature change in the absorber 52 or at least an increase in the cooling requirement. By measuring the temperature or its change behavior, the evaporation rate and / or the flux distribution of the source material 20 evaporated or sublimed by the impinging electromagnetic radiation 120 can be determined.

[0099] Figure 2Depicts a cross-section of a feasible embodiment of the detector 40 according to the present invention. The detector 40 includes a single sensor element 50 having an absorber 52, and the absorber 52 is preferably made of a metal with high thermal conductivity (such as copper or aluminum). The arrangement element 40 allows the absorber 52 to be arranged at the vacuum feedthrough 14 of the vacuum chamber 12 of the system 10 according to the present invention. In particular, the arrangement element 42 includes a positioning element 44 that changes the actual position of the absorber 52 within the reaction atmosphere 16 of the vacuum chamber 12. Thus, the movement of other elements (such as the source material 20) of the system 10 arranged in the vacuum chamber 12 can be provided, see Figure 1 , without any hindrance caused by the detector 40.

[0100] The detector 40 according to the present invention is based on the principle of a bolometer. Electromagnetic radiation 120 impinges on the absorption surface 60 of the absorber 52 and is at least partially absorbed. This energy deposition can be measured by measuring the absolute temperature or temperature change of the absorber 52.

[0101] For this purpose, in the detector 40 according to the present invention, two different measurement methods and corresponding sensing elements 70 are implemented. The corresponding methods can be used alone to measure the temperature or its change. However, higher accuracy can be provided by combining the two methods described below.

[0102] For the first method, a temperature sensor 74 (preferably a thermocouple element 76) is arranged in the hole 54 of the absorber 52, particularly near the absorption surface 60. As described above, the energy deposited by the electromagnetic radiation 120 impinging on the absorption surface 60 causes the temperature of the absorber 52 to rise. The thermocouple 76 located near the absorption surface 60 within the absorber 52 can measure it as an absolute temperature or a temperature change. Thus, this measurement method also allows the amount of energy deposited into the absorber 52 to be accurately determined.

[0103] For the second method, the absorber 52 includes a cooling system 80 for active cooling. A coolant 84 flows through the cooling pipe 82 and through the absorber 52, thereby absorbing the energy deposited into the absorber 80 by the impinging electromagnetic radiation 120. As Figure 2 depicted, at the inlet and outlet of the cooling pipe 82 respectively, a flow sensor 72 measures the flow rate of the coolant 84, and a temperature sensor 74 measures the temperature of the coolant 84. In summary, these combined measurements allow the amount of energy deposited into the absorber 52 to be accurately determined.

[0104] Figure 3Shows a cross-section of a rotationally symmetric preferred embodiment of the detector 40 according to the present invention, in particular a cross-section of its absorption surface 60. According to this embodiment, the absorber 52 of the described sensor element 50 includes a hollow absorption volume 56 at the end facing the impact direction 122 of the electromagnetic radiation 120 to be measured. This absorption volume 56 includes a single opening, namely the absorption orifice 62, which allows the impinging electromagnetic radiation 120 to enter the absorption volume 56. The inner sidewall 58 of the absorption volume 56 forms the absorption surface 60. In other words, the electromagnetic radiation 120 enters the absorption volume 120 and is reflected multiple times within the absorption volume 56, as Figure 3 indicated by the arrows, whereby, at each reflection, a portion of the energy of the impinging electromagnetic radiation 120 is absorbed. Ideally, the electromagnetic radiation 120 is trapped within the absorption volume 56 and is thus completely absorbed by the absorption surface 60. To increase the likelihood of this ideal situation, the sidewall portion forming the edge 64 around the absorption orifice 62 is inclined inwardly relative to the absorption volume 56. This inwardly inclined surface provides the additional advantage that electromagnetic radiation impinging on these surfaces can be prevented from being reflected back in the impact direction. Additionally, the portion of the absorption surface 60 arranged opposite to the absorption orifice 62 has a conical shape, with the cone tip pointing towards the absorption orifice 62.

[0105] In Figure 4 , a detector 40 with two sensor elements 50 is shown. The sensor elements 50 are arranged adjacent to each other and are thermally decoupled. Each sensor element 50 includes its own absorber 52 and absorption surface 60. The remaining parts of the sensor elements 50 are not shown. In summary, providing two or more sensor elements 50 can provide more detailed information about the absorbed electromagnetic radiation 120, for example, for determining the evaporation rate of the evaporation source material 20 and / or the magnetic flux distribution (not shown).

[0106] Additionally, upstream of each sensor element 50, two stacked and aligned apertures 90 are arranged. The aperture openings 92 limit the acceptance solid angle of the corresponding sensor element 50. Crosstalk between the sensor elements 50 indicated by the dashed arrows can be avoided. Further, between the apertures 90 and the absorbers 52, and even further along the respective absorbers 52, shielding elements 94 are arranged. On the one hand, these shielding elements 94 further reduce the above-mentioned crosstalk. On the other hand, electromagnetic radiation 120 impinging on the side surfaces of the absorbers 52 is also blocked and cannot distort the measurement results.

[0107] As mentioned with reference to Figure 4 , the detector 40 according to the present invention can include two or more sensor elements 50. Figure 5Several examples of the shape and arrangement pattern of the sensor element 50 and its absorption surface 60 are shown. Obviously, in one limitation, other arrangements similar to a high-resolution pixel array of an electronic camera are possible. In summary, the most suitable arrangement pattern can be selected from different arrangement patterns for the measurement purpose of the detector 40, such as determining the evaporation rate and / or the magnetic flux distribution of the evaporation source material 20.

[0108] A standard geometry with a simplified circular effective area is shown in Figure 5 the upper left part of.

[0109] The movement of the impact direction 122 of the electromagnetic radiation 120 can be detected using four quadrants as shown in the upper right part. Here, the sensor element 50 is shaped as a square and arranged such that movement mainly along its diagonals in the horizontal and vertical directions can be detected while keeping the number of sensor elements 50 small.

[0110] Figure 5 A third arrangement of the sensor element 50 with a rotationally symmetric pattern forming an annulus is shown in the lower left part of. This pattern is most sensitive to the focusing or defocusing of the electromagnetic radiation 120 provided by the electromagnetic radiation source 110.

[0111] Both the position and defocus (although only in the vertical direction in this case) can be detected by a striped arrangement of rectangular-shaped sensor elements 50, such as Figure 5 shown in the lower right part of. This would be advantageous because the electromagnetic radiation 120 reflected on the source surface 22 at an impact direction 122 of about 45° is more strongly affected in the plane containing the incident and reflected beams than perpendicular to the beam.

[0112] The following three Figure 6 、 7 and 8 show the influence of the shape and form of the source surface 22 of the source material on the magnetic flux distribution 30 of the evaporation source material 20 and the distribution of the electromagnetic radiation 120 reflected on the source surface 22 into the measurement distribution 134 on the detector 40. In the following, Figure 6 、 Figure 7 and Figure 8 will be described together, thereby highlighting the differences in the figures. Additionally, the method according to the invention will be described.

[0113] The electromagnetic radiation source 110 provides the electromagnetic radiation 120 with an impact distribution 130. This provision of the electromagnetic radiation 120 is completed in step c) of the method according to the invention. According to step a), the impact distribution 130 is defined such that the magnetic flux distribution 30 of the source material 20 evaporated from the source surface 22 also corresponds to the defined desired distribution 32 of the source material 20 evaporated and / or sublimated in step a). Especially in Figure 6In the case of the flat source surface 22 shown, this condition can be easily met. The target material 18 arranged opposite the source material 20 in the reaction atmosphere 16 can be coated with the evaporated source material 20 as expected.

[0114] To allow control of this coating process, the detector 40 is arranged such that the electromagnetic radiation 120 reflected on the source surface 22 in the impact direction 122 can be measured, particularly in step d) of the method according to the invention. Thus, preferably taking into account the response function of the detector 40, the detector 40 provides a measurement distribution 134 of the measured electromagnetic radiation 120. Since any change in the form and / or shape of the source surface 22 will imprint itself on the reflected electromagnetic radiation 120, this measurement distribution 134 can be used to detect any deviation from the assumed ideal situation.

[0115] For this purpose, in the second step b) of the method according to the invention, the expected distribution 132 of the reflected electromagnetic radiation 120 is determined (e.g., calculated, empirically estimated or experimentally determined). By comparing the measurement distribution 134 of the electromagnetic radiation 120 reflected on the source surface 22 with the expected distribution 132 in step f) of the method according to the invention, the difference between these two distributions 132, 134 can be determined.

[0116] Based on the differences found in step f) of the method according to the invention, step g) includes re - determining the impact distribution 130 in order to eliminate these differences. Finally, in the last step h), the electromagnetic radiation source 110 provides the electromagnetic radiation 120 with the newly re - determined impact distribution 130, for example a laser with a wavelength between 100 nm and 1400 nm. Thus, an actual control of the flux distribution 30 of the evaporated source material 20 can be provided.

[0117] In particular, steps d) to h) of the method according to the invention can be performed at least repeatedly to provide an active closed - loop control of the evaporation. Alternatively or additionally, in step a), the time correlation can already be used to limit the desired distribution 32.

[0118] As described above, in Figure 6 the source material 20 with a flat source surface 22 is shown. This is the ideal case and is easy to calculate. The actual flux distribution 30 is equal to the desired distribution 32.

[0119] After some irradiation of the electromagnetic radiation 120, for example due to the actual evaporation of the source material 20, the source surface 22 can form a recess. Thereby, the flux distribution 30 and the distribution of the reflected electromagnetic radiation change respectively. The flux distribution 30 is no longer equal to the desired distribution 32 (not shown). By comparing the newly measured distribution 134 with the expected distribution 132, this situation can be identified and resolved by correspondingly re - determining the impact distribution 130.

[0120] Figure 8 shows a situation similar to Figure 7 . The only difference lies in the shape of the source surface 22, which is not concave but convex. All descriptions regarding the distributions 30, 130, 132, 143 and the solution methods presented above are the same as those regarding Figure 7 described and are hereby incorporated by reference.

[0121] In Figure 9 , some special behavior of the source material 20 is shown. The source material 20 is provided as a self - supporting rod, whereby the source surface 22 is arranged at the upper end of the rod. By irradiating the source surface 22 with impinging electromagnetic radiation 120, droplets of the melted source material 20 are created at this upper end of the rod formed by the source material 20. When the electromagnetic radiation 120 impinges at an angle (e.g., 45°), the side of the rod closer to the electromagnetic radiation 120 absorbs more energy. As a result, the droplets of the melted source material 20 tilt and / or skew in the direction of the electromagnetic radiation 120. In particular, the magnetic flux distribution 30 also follows this spatial orientation.

[0122] Figure 10 shows a feasible solution to this problem. According to the method of the present invention, a second beam of electromagnetic radiation 120 can be used to balance the energy deposited into the source material 20. The magnetic flux distribution 30 is no longer distorted and again equals the desired distribution 32.

[0123] The number of beams of electromagnetic radiation 120 is not limited to two. Figure 11 shows an embodiment of a system 10 according to the present invention, which has an electromagnetic radiation source 110 including three emitter parts 112. The emitter parts 112 are arranged rotationally symmetrically around the source surface 22 on the source material 20. For each beam of electromagnetic radiation 120, a dedicated detector 40 is provided. Thus, the above - described method according to the present invention can be carried out separately and in combination using each pair of emitter parts 112 and detector 40. In particular, the emitter parts 112 can provide the electromagnetic radiation 120 with an adjustable power density and / or shape and / or size. Thus, the actual impinging distribution 130 and thus also the magnetic flux distribution 30 and the desired distribution 32 can provide a uniform spatial variation at the source surface 22.

[0124] This situation is in Figure 12is described. Two impinging electromagnetic radiation beams 120 are shown, whereby their impingement distributions 130 are different, as indicated by the different thicknesses of the arrows. Such a difference, provided for example by different power densities of the provided electromagnetic radiation beams 120, results in a slight distortion of the magnetic flux 30 of the source material 20 evaporated from the source surface 22. In this case, this is intentional and the magnetic flux distribution 30 equals the desired distribution 32. It is clearly visible that when the magnetic flux distribution 30 is directed to one side of the target material 18, the target material 18 will not be evenly coated by this magnetic flux distribution 30. By varying the individual impingement distributions 130 of the electromagnetic radiation beams 120, the direction of the magnetic flux distribution 30 can be changed. Thus, the desired deposition thickness or thickness variation or the time-dependent scanning of the desired distribution 32 on the target material 18 can be achieved and tracked by the actual magnetic flux distribution 30.

[0125] List of reference numerals

[0126] 10 System

[0127] 12 Vacuum chamber

[0128] 14 Vacuum feedthrough

[0129] 16 Reaction atmosphere

[0130] 18 Target material

[0131] 20 Source material

[0132] 22 Source surface

[0133] 30 Magnetic flux distribution

[0134] 32 Desired distribution

[0135] 40 Detector

[0136] 42 Arrangement element

[0137] 44 Positioning element

[0138] 50 Sensor element

[0139] 52 Absorber

[0140] 54 Hole

[0141] 56 Absorption volume

[0142] 58 Side wall

[0143] 60 Absorption surface

[0144] 62 Absorption orifice

[0145] 64 Edge

[0146] 70 Thermal sensing element

[0147] 72 Flow Sensor

[0148] 74 Temperature Sensor

[0149] 76 Thermocouple Element

[0150] 80 Cooling System

[0151] 82 Cooling Pipe

[0152] 84 Coolant

[0153] 90 Aperture Diameter

[0154] 92 Aperture Opening

[0155] 94 Shielding Element

[0156] 110 Electromagnetic Radiation Source

[0157] 112 Transmitter Section

[0158] 120 Electromagnetic Radiation

[0159] 122 Impact Direction

[0160] 130 Impact Distribution

[0161] 132 Expected Distribution

[0162] 134 Measured Distribution

Claims

1. A method for the magnetic flux distribution (30) of evaporation source material (20) in a control system (10), the system (10) being used for thermal evaporation using electromagnetic radiation (120), wherein, the system (10) includes: an electromagnetic radiation source (110) for providing electromagnetic radiation (120); a vacuum chamber (12) containing a reaction atmosphere (16); and a detector (40) for measuring electromagnetic radiation (120), wherein the source material (20) and the target material (18) to be coated are arranged in the vacuum chamber (12), and the radiation source is arranged such that its electromagnetic radiation (120) impinges on the source surface (22) of the source material (20) at an angle to thermally evaporate and / or sublime the source material (20) below the plasma threshold, and wherein the detector (40) for measuring electromagnetic radiation (120) is arranged such that the electromagnetic radiation (120) reflected on the source surface (22) reaches the detector (40), the method includes the following steps: a) Defining a desired distribution (32) of the magnetic flux of the source material evaporated from the source surface (22) and an impingement distribution (130) of the electromagnetic radiation (120) required for the desired distribution (32); b) Determining an expected distribution (132) of the electromagnetic radiation (120) reflected on the source surface (22) based on the desired distribution (32) and the impingement distribution (130) of step a); c) Providing electromagnetic radiation (120) through the electromagnetic radiation source (110) with the required impingement distribution (130) defined in step a); d) Measuring the electromagnetic radiation (120) reflected on the source surface (22) through the detector (40); e) Determining a measured distribution (134) of the electromagnetic radiation (120) reflected on the source surface (22) based on the measurement data of step d); f) Determining the difference between the expected distribution (132) determined in step b) and the measured distribution (134) determined in step e); g) Redetermining the required impingement distribution (130) of the electromagnetic radiation (120) provided by the electromagnetic radiation source (110) to minimize the difference determined in step f); and h) Providing electromagnetic radiation (120) through the electromagnetic radiation source (110) with the required impingement distribution (130) redetermined in step g).

2. The method according to claim 1, the radiation source is arranged such that its electromagnetic radiation (120) impinges on the source surface (22) of the source material (20) at an angle of 45°.

3. The method according to claim 1, wherein, the desired distribution (32) defined in step a) includes a time correlation.

4. The method according to claim 1, wherein, the expected distribution (132) in step b) is determined by calculating the expected distribution (132) and / or experimentally measuring the expected distribution (132) and / or empirically estimating the expected distribution (132).

5. The method according to claim 1, wherein, steps d) to h) are repeatedly executed.

6. The method according to claim 1, wherein, light having a wavelength between 100 nm and 1400 nm is used as the electromagnetic radiation (120).

7. The method according to claim 1, wherein, the light used as the electromagnetic radiation (120) is a laser.

8. The method according to claim 1, in step e) and / or step f), the response function of the detector (40) is taken into account.

9. The method according to claim 1, wherein, in step f), the dimensions and / or shape of the expected distribution (132) and the measured distribution (134) are used to determine the difference.

10. The method according to claim 1, wherein, the electromagnetic radiation source (110) includes two or more emitter portions (112), whereby, in steps c) and h), each emitter portion (112) provides electromagnetic radiation (120) that impinges on the source surface (22), and wherein the system (10) correspondingly includes two or more detectors (40), and each detector (40) is correspondingly arranged to measure electromagnetic radiation (120) provided by one of the emitter portions (112) and reflected on the source surface (22).

11. The method according to claim 10, wherein, the corresponding electromagnetic radiation (120) provided by the two or more emitter portions (112) impinges on the source surface (22) radially symmetrically.

12. The method according to claim 10, wherein, the two or more emitter portions (112) provide electromagnetic radiation (120) with an adjustable power density and / or shape and / or dimensions.

13. A system (10) for thermal evaporation using electromagnetic radiation (120), comprising: an electromagnetic radiation source (110) for providing electromagnetic radiation (120); a vacuum chamber (12) containing a reactive atmosphere (16); and a detector (40) for measuring electromagnetic radiation (120), wherein a source material (20) and a target material (18) to be coated are arranged in the vacuum chamber (12), and the radiation source is arranged such that its electromagnetic radiation (120) impinges on the source surface (22) of the source material (20) at an angle to thermally evaporate and / or sublime the source material (20) below the plasma threshold, wherein the detector (40) for measuring electromagnetic radiation (120) is arranged such that the electromagnetic radiation (120) reflected on the source surface (22) reaches the detector (40), wherein the system (10) is adapted to perform the method according to any one of claims 1 to 12.

14. The system (10) according to claim 13, wherein, The detector (40) is configured to measure electromagnetic radiation (120) reflected on a source surface (22), and includes a sensor element (50) having an absorber (52), the absorber (52) including an absorption surface (60) for at least partially absorbing the electromagnetic radiation (120), wherein the sensor element (50) further includes a thermal sensing element (70) for measuring the temperature of the absorber (52) to detect the absolute temperature and / or temperature change caused by the absorbed electromagnetic radiation (120) in the absorber (52). Wherein, the thermal sensing element (70) includes a temperature sensor (74) disposed in a hole (54) in the absorber (52), and the hole (54) terminates within the absorber (52).

15. The system (10) according to claim 14, wherein, the temperature sensor (74) is a thermocouple element (76).

16. The system (10) according to claim 14, the hole (54) terminates within the absorber (52) near the absorption surface (60).

17. The system (10) according to claim 14, wherein, the absorption surface (60) absorbs light having a wavelength between 100 nm and 1400 nm.

18. The system (10) according to claim 17, wherein, the absorption surface (60) absorbs a laser having a wavelength between 100 nm and 1400 nm.

19. The system (10) according to claim 14, wherein, the absorber (52) includes a cooling system (80) for active cooling of the absorber (52), and thereby, the cooling system (80) includes at least one cooling pipe within the absorber (52) for flowing a coolant (84) through the absorber (52).

20. The system (10) according to claim 19, wherein, the coolant (84) is water.

21. The system (10) according to claim 20, wherein, the thermal sensing element (70) includes a flow sensor (72) and a temperature sensor (74), the flow sensor (72) for measuring the flow rate of the coolant (84) through the cooling pipe in the absorber (52), the temperature sensor (74) for measuring the absolute temperature and / or temperature change of the coolant (84) caused by the coolant (84) flowing through the cooling pipe in the absorber (52).

22. The system (10) according to claim 14, wherein, the absorber (52) includes a metal.

23. The system (10) according to claim 22, wherein, the absorber (52) includes copper or aluminum.

24. The system (10) according to claim 22, wherein, the absorber (52) is made of metal.

25. The system (10) according to claim 22, wherein, the absorber (52) is made of copper or aluminum.

26. The system (10) according to claim 14, wherein, the absorber (52) surrounds a hollow absorption volume (56) at one end, whereby an inner wall (58) of the absorption volume (56) forms the absorption surface (60), and wherein the absorption volume (56) includes an absorption orifice (62), whereby the absorption orifice (62) can be aligned with a supposed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured.

27. The system (10) according to claim 26, wherein, the absorption surface (60) is partially conical within the absorption volume (56), wherein the cone of the conical absorption surface (60) faces the absorption orifice (62).

28. The system (10) according to claim 27, wherein, a part of the absorption volume (56) forming an edge (64) of the absorption orifice (62) is inclined inwards relative to the absorption volume (56).

29. The system (10) according to claim 26, wherein, the detector (40) includes an aperture (90) having an aperture opening (92), wherein the aperture (90) is arranged upstream of the sensor element (50) along a supposed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured.

30. The system (10) according to claim 29, wherein, the size of the aperture opening (92) is adapted to the absorber (52) such that the electromagnetic radiation (120) entering through the aperture opening (92) impinges on the absorption surface (60) of the absorber (52).

31. The system (10) according to claim 30, wherein, the size of the aperture opening (92) is adapted to the absorption orifice (62).

32. The system (10) according to claim 30, wherein, the size of the aperture opening (92) is adapted to the absorber (52) such that the electromagnetic radiation (120) entering through the aperture opening (92) impinges on the absorption surface (60) of the absorber (52) through the absorption orifice (62).

33. The system (10) according to claim 30, wherein, the size of the aperture opening (92) is adapted to the absorption orifice (62) such that the electromagnetic radiation (120) entering through the aperture opening (92) impinges on the absorption surface (60) of the absorber (52) through the absorption orifice (62).

34. The system (10) according to claim 29, wherein, the detector (40) includes a shielding element (94), wherein the shielding element (94) extends between the aperture (90) and the absorber (52) along the supposed and / or determined impact direction (122) of the electromagnetic radiation (120).

35. The system (10) according to claim 34, wherein, The shielding element (94) further extends along the absorber (52) in the assumed impact direction (122) of the electromagnetic radiation (120).

36. The system (10) according to claim 14, wherein, the detector (40) includes two or more sensor elements (50), whereby the two or more sensor elements (50) are adjacent to each other and are thermally decoupled.

37. The system (10) according to claim 36, wherein, the two or more sensor elements (50) are arranged in a rotationally symmetric pattern or in rows or a matrix in a plane perpendicular to or at least substantially perpendicular to the assumed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured.

38. The system (10) according to claim 36, wherein, in a plane perpendicular to or at least substantially perpendicular to the assumed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured, the two or more sensor elements (50) include one of the following shapes: - rectangular - square - circular - annular - annular segment.

39. The system (10) according to claim 14, wherein, the detector (40) includes: an arrangement element (42) for arranging the absorber (52) at the vacuum feedthrough (14).

40. The system (10) according to claim 39, wherein, the arrangement element (42) includes: a positioning element for changing the position of the absorber (52) relative to the vacuum feedthrough (14).

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