A method for controlling the evaporation rate of a source material, a detector for measuring electromagnetic radiation reflected from the source surface, and a system for thermal evaporation by electromagnetic radiation.

Abstract

The present invention relates to a method for controlling the evaporation rate of a source material (20) in a system (10) for thermal evaporation by electromagnetic radiation (120), the system (10) comprising an electromagnetic radiation source (110) providing the electromagnetic radiation (120), a vacuum chamber (12) containing a reaction atmosphere (16), and a main detector (40, 100) measuring the electromagnetic radiation (120), the source material (20) and a target material (18) to be coated being disposed within the vacuum chamber (12), the electromagnetic radiation source (110) controlling the rate of evaporation of the source material (20) on a source surface (22) of the source material (20) for thermal evaporation and / or sublimation of the source material (20) below a plasma threshold. The electromagnetic radiation (120) is incident on the source surface (22) at a predetermined angle, preferably 45°, and the main detector (40, 100) for measuring the electromagnetic radiation (120) is configured so that the electromagnetic radiation (120) reflected from the source surface (22) reaches the main detector (40, 100), and the source material (20) is provided by a source element (24), and the source surface (22) is arranged at the source element (24) in a state accessible to the electromagnetic radiation (120), whereby the source element (24) is arranged within a holding structure (28) and is movable by the holding structure (28) perpendicular to the source surface (22). The present invention also relates to a detector (40) for measuring the electromagnetic radiation (120), preferably a detector (40) suitable for the method of the present invention, and also to a system (10) for thermal evaporation having electromagnetic radiation (120) suitable for the method of the present invention.

Description

Technical Field

[0001] The present invention relates to a method for controlling the evaporation rate of a source material in a system for thermal evaporation by electromagnetic radiation. The system has an electromagnetic radiation source that provides electromagnetic radiation, a vacuum chamber that houses a reaction atmosphere, and a main detector that measures the electromagnetic radiation. The source material and the target material to be coated are arranged in the vacuum chamber. The electromagnetic radiation source is configured such that its electromagnetic radiation is incident at a predetermined angle, preferably at an angle of 45°, on the source surface of the source material for thermal evaporation and / or sublimation of the source material below the plasma threshold. The main detector for measuring the electromagnetic radiation is configured such that the electromagnetic radiation reflected on the source surface reaches the main detector. Furthermore, the source material is provided by a source element, and the source surface is arranged in a state accessible to the electromagnetic radiation in the source element. Thus, the source element is arranged in a holding structure and is movable by the holding structure.

[0002] Furthermore, the present invention relates to a detector for measuring the electromagnetic radiation reflected on the source surface, which has a sensor element with an absorption body. The absorption body has an absorption surface that at least partially absorbs the electromagnetic radiation. The sensor element further has a thermosensing element that measures the temperature of the absorption body to detect the absolute temperature and / or temperature change generated in the absorption body by the absorbed electromagnetic radiation.

[0003] In addition, the present invention relates to a system for thermal evaporation by electromagnetic radiation, comprising an electromagnetic radiation source that provides electromagnetic radiation, a vacuum chamber that contains a reaction atmosphere, and a main detector that measures electromagnetic radiation, wherein the source material and the target material to be coated are arranged in the vacuum chamber, the electromagnetic radiation source is configured such that its electromagnetic radiation is incident on the surface of the source material at a predetermined angle, preferably 45°, for thermal evaporation and / or sublimation of the source material below a plasma threshold, and the main detector that measures electromagnetic radiation is configured such that the electromagnetic radiation reflected from the source surface reaches the main detector. [Background technology]

[0004] The use of electromagnetic radiation, particularly lasers with wavelengths in the visible, infrared, or ultraviolet range, for the evaporation of source materials is commonly known. Such laser evaporation systems allow for the deposition of thin films of material at low pressure by heating the center of a block of source material from the front with a continuous-wave laser. For example, silicon achieves the desired flow of evaporated material, thereby melting at the temperature required to form a molten pool inside the solid portion of the same source material. Thus, solid Si forms a crucible for liquid Si, allowing for very large heating and cooling rates due to the absence of 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, crucibles made of materials different from the material to be evaporated are also used.

[0005] However, as the source material is consumed by the incident electromagnetic radiation, the source surface changes shape, for example, by forming a recessed shape in the molten pool and / or by carving increasingly deeper sublimation spots into the source material. Consequently, since the shape of the source surface directly affects the evaporation rate and the flow distribution of the evaporated material, the evaporation rate and flow distribution of the evaporated source material are inherently unstable.

[0006] A known method for overcoming this problem is to move a spot of electromagnetic radiation on the source material to obtain a relatively uniform distribution of energy storage and, consequently, of the evaporated source material. Furthermore, since the support points for the source material are almost always located on its outer edge close to the evaporation surface, evaporation or sublimation from the entire surface of the source is not practical. In addition, since the evaporation surface still does not strictly have a constant shape and / or orientation, at least in time, the motion of the source itself also introduces fluctuations. [Overview of the project] [Problems that the invention aims to solve]

[0007] In view of the above, the object of the present invention is to provide an improved method for controlling the evaporation rate of a source material that does not have the aforementioned drawbacks of the prior art in this field, an improved detector for measuring electromagnetic radiation reflected from the source surface, and an improved system for thermal evaporation by electromagnetic radiation. Specifically, the object of the present invention is to provide a method, detector, and system that allow control of the evaporation rate of a source material in a system for thermal evaporation by electromagnetic radiation in a particularly simple and cost-effective manner, preferably the evaporation rate can be adjusted to both large and small values, particularly in closed-loop control. [Means for solving the problem]

[0008] This objective is satisfied by the individual independent patent claims. Specifically, this objective is satisfied by the method described in claim 1, by the detector described in claim 12, and by the system described in claim 29. Dependent claims describe preferred embodiments of the present invention. Details and advantages described in relation to the method according to the first aspect of the present invention also refer to the detector according to the second aspect of the present invention and the system according to the third aspect of the present invention, and vice versa, where there is technical significance.

[0009] According to a first aspect of the present invention, the objective is satisfied by a method for controlling the evaporation rate of a source material in a system for thermal evaporation by electromagnetic radiation, the system comprising an electromagnetic radiation source that provides electromagnetic radiation, a vacuum chamber containing a reaction atmosphere, and a main detector for measuring electromagnetic radiation, wherein the source material and the target material to be coated are arranged in the vacuum chamber, the electromagnetic radiation source is configured such that its electromagnetic radiation is incident on the source surface of the source material at a predetermined angle, preferably 45°, for thermal evaporation and / or sublimation of the source material below a plasma threshold, the main detector for measuring electromagnetic radiation is configured such that the electromagnetic radiation reflected from the source surface reaches the main detector, and furthermore, the source material is provided by a source element, the source surface is arranged in a state accessible to electromagnetic radiation on the source element, thereby the source element is arranged within a holding structure and is movable by the holding.

[0010] The method according to the present invention is a) A step of providing electromagnetic radiation by an electromagnetic radiation source, b) The main detector measures the electromagnetic radiation reflected from the source surface, c) A step of analyzing the measurement data obtained in step b), d) Adjusting the evaporation rate based on the results of the analysis in step c) by moving the source element in relation to electromagnetic radiation and / or adjusting the power of the electromagnetic radiation and / or adjusting the size and / or shape of the cross-section of the electromagnetic radiation, Includes.

[0011] The method according to the present invention can be used in and in a system for the thermal evaporation of a source material by electromagnetic radiation. The evaporated source material can be used to coat a target material, preferably, for example, in the form of a thin film. The source material and target material are arranged in a vacuum chamber of the system, which 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 it can contain any required reaction gases such as oxygen and / or nitrogen.

[0012] In the case of an evaporation process, an electromagnetic radiation source provides electromagnetic radiation, which is guided into a vacuum chamber and incident on the source surface of the source material. The energy accumulation of the electromagnetic radiation causes the source material to evaporate or sublimate. The energy accumulation is selected so as not to reach the plasma threshold of the source material. Thus, it is possible to provide purely thermal evaporation of the source material without the formation of any plasma. By incident at a predetermined angle, preferably at an angle of 45°, collisions of the path of electromagnetic radiation within the vacuum chamber with other structures in the vacuum chamber, such as the source and / or target holding elements, can be avoided.

[0013] Only a portion of the electromagnetic radiation incident on the source surface is absorbed by the source material and used for the evaporation process. The remaining portion of the electromagnetic radiation is reflected on the source surface. In other words, the absorbed and reflected portions of the electromagnetic radiation are directly linked to each other. By detecting the reflected portion, the amount of electromagnetic radiation absorbed by the source material can be estimated. For the detection of reflected electromagnetic radiation, the method according to the present invention uses a main detector appropriately positioned within a vacuum chamber in the path of the reflected electromagnetic radiation.

[0014] As described above, the measured reflected electromagnetic radiation allows for an estimation of energy storage within the source material and, therefore, the evaporation rate of the source material. Since the desired evaporation rate is known, it is possible to determine whether the actual evaporation rate is excessive or underestimated.

[0015] Specifically, the system for the method according to the present invention has a holding structure for a source element, which can move the source element in relation to electromagnetic radiation. Therefore, the relative position of the source surface and the incident electromagnetic radiation can be changed based on the measured reflected electromagnetic radiation and the estimated actual evaporation rate in order to change the actual evaporation rate and to approximate a desired evaporation rate by the actual evaporation rate.

[0016] The individual steps of the method according to the present invention will be described in detail below.

[0017] In the first step a) of the method according to the present invention, electromagnetic radiation is provided by an electromagnetic radiation source. The electromagnetic radiation source can be directly mounted in a vacuum chamber. Alternatively, the electromagnetic radiation source can be positioned at a distance from the vacuum chamber, possibly in a different room or building. The electromagnetic radiation can be guided into the vacuum chamber by a suitable guide element, such as an optical fiber. As a result, the electromagnetic radiation is incident on the source surface of the source material, causing the source material to thermally evaporate or sublimate below the plasma threshold.

[0018] Simultaneously, portions of electromagnetic radiation not absorbed by the source material are reflected on the source surface. In a subsequent step b) of the method according to the present invention, this reflected electromagnetic radiation is measured by the system's main detector. For this purpose, the main detector is appropriately positioned within a vacuum chamber.

[0019] The measurement data obtained in step b) of the method according to the present invention is analyzed in the subsequent step c). Since the detector response function, the properties of the incident electromagnetic radiation, and the desired evaporation rate are known, the remaining required absorbed electromagnetic radiation, and therefore, the reflected portion of the electromagnetic radiation, can be determined. By comparing the measurement of the main detector in step b) with the prediction in relation to the reflected electromagnetic radiation, it is possible to estimate whether the desired evaporation rate is satisfied.

[0020] If the actual evaporation rate estimated in step c) differs from the desired evaporation rate, the evaporation rate can be adjusted in the final step d) of the method according to the present invention to satisfy the specifications. This adjustment can be provided by various means.

[0021] For example, by moving the source element, the illumination of the source surface by incident electromagnetic radiation can be changed. As a result, the evaporation rate will increase or decrease, respectively.

[0022] Alternatively, or in addition to this, the power, particularly the power density, and / or the size and / or shape of the cross-section of the electromagnetic radiation can be adjusted. The power of the electromagnetic radiation directly affects the evaporation rate, as relatively high power results in relatively high energy storage. By changing the size and / or shape of the cross-section of the electromagnetic radiation, the fit of the incident electromagnetic radiation to the size and / or shape of the source surface can be changed, particularly improved. Furthermore, relatively good, preferably complete, illumination of the source surface by electromagnetic radiation will result in an increase in the evaporation rate.

[0023] In short, the method according to the present invention described above allows for the active adjustment of the evaporation rate during the operation of individual evaporation systems based on actual measurements. Therefore, the evaporation rate can be controlled. As a result, the coating of the target material can be further improved by the method according to the present invention.

[0024] Furthermore, the method according to the invention can have, in step d), the source element moving in a state perpendicular and / or parallel to the source surface. The movement of the source element in a state perpendicular to the source surface will shift the source surface either towards or away from the center of the incident electromagnetic radiation. By moving the source element parallel to the source surface, it is possible to maximize the portion of the radiation that is reflected, which corresponds to maximum absorption, and this often coincides with the centering of the beam on the source surface.

[0025] In addition to this, the method according to the invention can be characterized in that the source element is provided as a self - supporting structure, especially as a rod, having, in particular composed of, a source material having a source surface arranged at the upper end of the source element, especially of the rod. In this embodiment, the source element is in a self - supporting state, i.e., no further crucible is required to provide the source material within the vacuum chamber. Thus, contamination of the source material due to reaction with the crucible material can be avoided. Specifically, the self - supporting source element carries the source surface on its upper end. For example, a holding structure such as some appropriately configured wheel or pulley can be arranged at a distance from the source surface. This can be particularly easily provided in the embodiment of the source element as a rod. The source element, especially the rod, can be raised and lowered in step d) of the method according to the invention in order to adjust the illumination of the source surface on its upper end by electromagnetic radiation, and thus functions similarly to a candle, with the radiation occupying the position of the wick of the candle, and an appropriate relative adjustment of the wick and the diameter of the candle resulting in a static consumption of the wax without dripping at the edges or formation of walls.

[0026] In a further improved embodiment of the method according to the invention, the rod is provided with at least a substantially circular rod cross-section, and the electromagnetic radiation is provided with an elliptical beam cross-section, whereby the rod cross-section and the beam cross-section are selected in a mutually adapted state. As the electromagnetic radiation is incident on the source surface at a predetermined angle, preferably at an angle of 45°, an elliptical cross-section is projected onto the source surface. Preferably, the adaptation of the cross-section of the electromagnetic radiation to the circular cross-section of the source surface can be selected such that the above-mentioned projection of the electromagnetic radiation on the source surface also becomes circular. In other words, it is possible to provide complete illumination of the source surface, and in addition, it is possible to prevent the outshining of the source surface by the electromagnetic radiation. In addition, the adaptation of the elliptical cross-section of the electromagnetic radiation will provide a particularly uniform and adapted illumination of the source surface.

[0027] According to an alternative embodiment of the method according to the invention, the source element has a crucible for containing the source material, whereby the crucible is transparent or at least partially transparent to electromagnetic radiation in a state where the source surface is arranged within the crucible. This embodiment is particularly suitable for source materials that cannot be provided as self-supporting source elements. In particular, the crucible is selected to be transparent to electromagnetic radiation, for example, by using a crucible having or composed of sapphire. Therefore, the evaporation of the source material is not hindered by the crucible, for example, when the source surface is arranged within the crucible after some evaporation of the source material. Also, in this embodiment, the crucible can be raised and lowered so as to provide a movement of the source material perpendicular to the source surface. Therefore, in this special embodiment having a further and separate crucible, it is also possible to provide the advantages of the above-mentioned method, specifically, the adjustment of the evaporation rate based on the measurement of the electromagnetic radiation reflected on the source surface.

[0028] Furthermore, the method according to the present invention may utilize, in particular, laser light having a wavelength of 100 nm to 1400 nm as electromagnetic radiation. Light, especially laser light, is easy to provide and, in particular, can be easily guided from a light source far from the vacuum chamber to the vacuum chamber. More specifically, the light can provide a wide range of energy densities and thus can easily provide electromagnetic radiation for evaporation below the plasma threshold of a particular source material.

[0029] Specifically, the method according to the present invention can be improved in step b) by using a main detector having two or more sensor elements, wherein the two or more sensor elements are adjacent to each other and thermally discoupled. During evaporation, the source surface may change its spatial shape, and in particular, the source surface may establish a convex or concave shape. Furthermore, this spatial shape of the source surface causes focusing and defocusing effects, and affects the measurement results of the main detector because a portion of the reflected electromagnetic radiation simply escapes the main detector. By providing a main detector having two or more sensor elements, relatively accurate measurements of the reflected electromagnetic radiation can be obtained. Specifically, it is possible to detect changes in the spatial shape of the source surface because these changes result in a detectable difference in the reflected electromagnetic radiation measured by the two or more sensor elements. By providing these two or more sensor elements that are thermally discoupled, independent measurements of each sensor element can be provided. The configuration of the sensor elements being adjacent to each other ensures the minimization of the gap between the sensor elements in which the reflected electromagnetic radiation escapes the main detector within itself.

[0030] Furthermore, the method according to the present invention can be characterized in that, in step b), a first additional detector is used to measure electromagnetic radiation reflected on a side surface of the source element, distinct from the source surface, particularly perpendicular to the source surface, thereby the data measured by the first additional detector is used in steps c) and d). At a perfectly aligned position, electromagnetic radiation is incident on the source surface by its entire cross-section. As a result, the power of the incoming electromagnetic radiation is absorbed by the source material or reflected in the direction of the main detector. However, if the source surface is located above this ideal position described above, a portion of the incident electromagnetic radiation will be reflected on the front surface of the source element, for example, a self-supporting rod or otherwise a suitable provided portion of a transparent crucible. In this case, the intensity of the electromagnetic radiation reflected on the source surface and subsequently measured by the main detector is reduced by the amount of incoming electromagnetic radiation reflected on the source element. However, by providing a first additional detector, it is possible to measure this portion of the incoming electromagnetic radiation reflected on the side surface of the source element, which can be taken into consideration later by determining the necessary adjustments provided in step d) of the method according to the present invention. This allows for improved control of the evaporation rate.

[0031] In addition, the method according to the present invention can be further improved by providing the side surface of the source element in a flat state. The flat surface will reflect the incoming electromagnetic radiation in a particularly predictable manner. Specifically, it is possible to avoid the dispersion of reflected electromagnetic radiation that occurs due to reflection on an arc-shaped surface. Thus, the analysis of the first further detector measurement performed in step c) of the method according to the present invention can be simplified.

[0032] According to a further embodiment of the method according to the present invention, the flat side surface is oriented perpendicular to a plane covered by the direction of electromagnetic radiation incident on the source surface and reflected thereby. In other words, the electromagnetic radiation is reflected on the side surface within the same plane as the electromagnetic radiation reflected on the source surface. Cross-sectional distortion of the electromagnetic radiation reflected on the flat side surface, which may occur due to glazing reflection, can be avoided, and the individual cross-sections remain particularly small and undistorted.

[0033] Alternatively, or preferably in addition thereto, the method according to the present invention may have, in step b), a second additional detector used to measure electromagnetic radiation that has escaped the source surface of the source element, thereby the data measured by the second additional detector being used in steps c) and d). As already noted above, at a perfectly aligned position, electromagnetic radiation, by its entire cross-section, is incident on the source surface, and the power of the incoming electromagnetic radiation is absorbed by the source material or reflected in the direction of the main detector. However, if the source surface is located below this ideal position described above, a portion of the incident electromagnetic radiation will escape the source surface, in particular the entire source element. In this case, the intensity of the electromagnetic radiation reflected on the source surface and subsequently measured by the main detector will be reduced by the amount of incoming electromagnetic radiation that escaped the source element. However, by providing a second additional detector, it is possible to measure this portion of the incoming electromagnetic radiation that escaped the source element, and this can be taken into account later by determining the necessary adjustments provided in step d) of the method according to the present invention. This allows for improved control of the evaporation rate.

[0034] As described above, a first additional detector can be used to identify the position of a source element above the ideal position, and a second additional detector can be used to identify the position of a source element below the ideal position. As a result, it is particularly preferable to provide both a first and a second additional detector. The measured intensity in the first additional detector increases with increasing upward deviation of the source element, and the intensity in the second additional detector increases with increasing downward deviation of the source element. By combining both signals, reliable and precise position control of the source element can be implemented. By relating the relative intensities of the detectors, changes in incoming electromagnetic radiation can be detected as proportional changes in the signals of the pair of detectors or all three. This allows for variation and control of the magnitude of all electromagnetic radiation without triggering corrective motion of the source element, and thereby independent control and optimization of both quantities. Similarly, focusing or defocusing of electromagnetic radiation results in inversely proportional intensity fluctuations between the main detector and additional detectors, thereby allowing for the discrimination and independent control of the positions of the electromagnetic radiation's focal and source elements.

[0035] In addition, in the case of non-constant incident laser intensity, for example, the detector intensity required for flow variation and control depends not only on the position of the source element but also on the incident laser intensity. However, the equation system can be uniquely determined by three measurements: two unknowns, namely the position and initial intensity of the electromagnetic radiation source, and a clear determination of both the incident laser intensity and the position of the source element. However, in the case of relatively inaccurate operation, or generally for further verification, the primary intensity of electromagnetic radiation provided and measured by the electromagnetic radiation source itself, which is being measured, can also be used, although this will be affected by possible variable losses within the entrance window due to its covering.

[0036] Furthermore, even in the case of an ideal cross-section setup, incident electromagnetic radiation that outshines the source surface by default can be used. In this case, the first and second additional detectors always detect some electromagnetic radiation. Also in this embodiment, the amount of electromagnetic radiation detected in all three implemented detectors can be used to adjust the position of the source element and thus control the evaporation rate. When operating with a typical Gaussian-shaped beam, the portion outshines the source is significantly less intense than that at the center of the beam, thus allowing this preferred mode of operation without significant power loss and associated efficiency reductions.

[0037] According to a second aspect of the present invention, the object is satisfied by a detector for measuring electromagnetic radiation reflected on a source surface, having a sensor element having an absorbent body, wherein the absorbent body has an absorbent surface that at least partially absorbs electromagnetic radiation, and the sensor element further has a thermal sensing element for measuring the temperature of the absorbent body to detect the absolute temperature and / or temperature change generated within the absorbent body by the absorbed electromagnetic radiation, wherein the absorbent body has a cooling system for active cooling of the absorbent body, wherein the cooling system has at least one cooling duct within the absorbent body for the flow of coolant, preferably water, through the absorbent body, and the thermal sensing element has a flow sensor for measuring the flow of coolant through the cooling duct within the absorbent body, and a temperature sensor for measuring the absolute temperature and / or temperature change of the coolant induced by flowing through the cooling duct within the absorbent body.

[0038] The detector according to the present invention can be used in a system for thermal evaporation by electromagnetic radiation. Specifically, such a detector can be used to measure electromagnetic radiation, for example, electromagnetic radiation reflected from the source surface of a source material.

[0039] The electromagnetic radiation being measured is incident on the absorption body, particularly on the absorption surface, and is at least partially absorbed by the absorption surface. In other words, at least a portion of the energy of the electromagnetic radiation is stored within the absorption body. Therefore, the measurement and monitoring of the temperature of the absorption body allow for the determination of energy storage within the absorption body, and thereby the determination of the amount of electromagnetic radiation incident on the absorption surface.

[0040] The absorption surface is at least partially opposite the source surface. Therefore, the absorption surface becomes covered with source material evaporated or sublimated from the source. Consequently, after a sufficiently long accumulation, the detector has the same absorptive and reflective properties as the source, which also means that these properties remain constant.

[0041] The absorption surface can be aligned, for example, perpendicular to the assumed incident direction of the electromagnetic radiation being measured. As only a portion of the incident electromagnetic radiation is absorbed, the remainder is reflected back in the same direction. In a thermal evaporation system in which the detector according to the present invention is used to measure electromagnetic radiation reflected off a source surface, the electromagnetic radiation reflected off such an absorption surface is guided back to the source surface and can be used for a second thermal evaporation.

[0042] However, a subsequent second reflection on the source surface can guide the electromagnetic radiation back to the electromagnetic radiation source, creating confusion. For example, one embodiment of an absorption surface having two flat sections adjacent to each other at an angle slightly less than 90°, such as 89°, can solve this problem. The electromagnetic radiation can still be reflected back onto the source surface, but not in exactly the same direction, thus causing the electromagnetic radiation source to miss its target. In addition, since the electromagnetic radiation incident on a two-fold absorption surface is reflected twice, the absorption of the incident electromagnetic radiation by the absorption surface is also doubled. This can improve energy storage within the absorption body and, therefore, the accuracy of the measurement.

[0043] To measure and / or monitor the amount of energy accumulated within the absorption body by incident electromagnetic radiation, the absolute temperature and / or temperature changes of the absorption body can be measured and / or monitored. In the detector according to the present invention, this measurement is performed by using the detector's cooling system.

[0044] The cooling ducts of the cooling system extend through an absorption body, allowing the flow of coolant through the absorption body. The coolant can be a fluid, and preferably water is used as the coolant. By flowing through the absorption body, the coolant cools the absorption body. Preferably, the cooling system maintains the supply at a constant temperature. In other words, the coolant flowing through the cooling ducts in the absorption body preferably absorbs any energy accumulated in the absorption body by incident electromagnetic radiation. As a result, the temperature of the coolant changes according to the amount of energy absorbed.

[0045] To measure the temperature and / or temperature changes of the coolant, the sensing element of the detector according to the present invention comprises two different types of sensors: a flow sensor and a temperature sensor. Specifically, the flow sensor measures the flow rate of the coolant flowing through the cooling duct. The temperature sensor measures the temperature of the coolant. Specifically, the temperature of the coolant is measured at least at the outlet of the cooling duct, and preferably also at the inlet of the cooling duct. The outlet temperature allows for the detection of temperature changes over time, assuming that the coolant is supplied at the inlet at a constant temperature. Measuring the inlet temperature of the coolant in addition can improve the measurement of this relative temperature change. In particular, by combining temperature measurement with the flow measurement described above, it is possible to determine the absolute value of energy storage generated by absorbed electromagnetic radiation into the absorption body. In particular, for example, based on the measurement of electromagnetic radiation reflected on the source surface by the detector according to the present invention, it is possible to estimate and subsequently control the evaporation rate of the source material.

[0046] Preferably, the detector according to the present invention has the capability that one or more detectors can be used in a method according to a first aspect of the present invention as a main detector and / or as a first further detector and / or as a second further detector. Accordingly, all the features and advantages detailed in relation to a method according to a first aspect of the present invention can also be provided by a detector according to a second aspect of the present invention used as a main detector, a first further detector, or a second further detector.

[0047] In addition, the detector according to the present invention can be characterized by the fact that the absorbing surface absorbs light having wavelengths of 100 nm to 1400 nm, particularly laser light. As described above in relation to the method according to the first aspect of the present invention, the light, particularly laser light, is suitable for the evaporation and / or sublimation of various possible source materials. By providing an absorbing surface having the ability to absorb light, the detector according to the present invention can be adapted to this particular electromagnetic radiation. The adaptation may include, for example, a suitable material selected for the absorbing body, on which the absorbing surface is formed. Alternatively, or in addition to this, a coating selected in an adaptable state of the absorbing surface for improving light absorption may also be used.

[0048] According to another embodiment of the detector according to the present invention, the thermal sensing element has a temperature sensor, particularly a thermocouple element, disposed in a bore within the absorption body, the bore terminating within the absorption body, preferably near the absorption surface. The bore allows for the placement of the temperature sensor near the absorption surface and thus improves the accuracy of temperature measurement. The temperature sensor within the absorption body allows for the direct measurement of the actual temperature of the absorption body and / or changes in this temperature. This additionally measured temperature value can be used to check the measurement of the coolant temperature and / or to improve the overall accuracy of temperature measurement. In addition, even if the temperature measurement based on the coolant fails or is completely absent, it is still possible to measure the temperature of the absorption body and, therefore, the energy deposited within the absorption body by electromagnetic radiation.

[0049] Furthermore, the detector according to the present invention may preferably have an absorption body that is made of or particularly composed of a metal, especially copper or aluminum. Metals as materials for the absorption body offer several advantages. Firstly, metals, especially copper or aluminum, have high thermal conductivity. The detector according to the present invention is designed as a bolometer, which has a sensor element for absorbing incident electromagnetic radiation and measuring the temperature and / or temperature change produced by this absorption. Materials with high thermal conductivity are particularly suitable for such bolometers. Moreover, metals are suitable materials for use under ultra-high vacuum conditions. Thus, contamination of such ultra-high vacuum as a reaction atmosphere by the detector according to the present invention can be avoided, and vice versa.

[0050] In a further preferred embodiment of the detector according to the present invention, the absorption body encloses a hollow absorption volume at one end, so that the inner sidewall of the absorption volume forms an absorption surface, the absorption volume having an absorption orifice, so that the absorption orifice can be aligned with the assumed and / or determined incident direction of the electromagnetic radiation being measured. Also, as described above, in most cases the absorption surface absorbs only a portion of the incident electromagnetic radiation, at least the electromagnetic radiation that is directly incident on the detector. In this preferred embodiment of the detector according to the present invention, the absorption surface is provided as the inner sidewall of a hollow absorption volume. Electromagnetic radiation incident on the detector enters the absorption volume through the absorption orifice. Within the absorption volume, the electromagnetic radiation is incident on the absorption surface, partially absorbed and partially reflected. As this reflection, which is preferably large in relation to the absorption orifice, occurs within the absorption volume, there is a large probability that the reflected electromagnetic radiation will miss the absorption orifice and hit the inner sidewall of the absorption volume, in other words, another section of the absorption surface. In the ideal case, this procedure is repeated until the incident electromagnetic radiation is completely, or at least essentially completely, absorbed by the absorbing body. In this case, the energy stored within the absorbing body represents the total energy of the incident electromagnetic radiation. In particular, this results in the creation of any coating on the absorbing surface with evaporated source material without any effect.

[0051] A further improved embodiment of the detector according to the present invention may have a partially conical shape within the absorption volume, such that the cone of the conically shaped absorption surface faces the absorption orifice. The cone can be shaped as both a projection and a recess, so that in the projection embodiment, the tip of the cone faces the absorption orifice, and in the recessed embodiment, the base of the cone faces the absorption orifice. In other words, electromagnetic radiation incident across the absorption orifice first enters the conically shaped portion of the absorption surface. Since the cone faces the absorption orifice, any electromagnetic radiation reflected from the side of the cone is directed into the interior of the absorption volume and will undoubtedly miss the absorption orifice. Thus, the above-mentioned ideal case of complete absorption of incident electromagnetic radiation within the absorption volume can be achieved relatively easily.

[0052] In addition, the detector according to the present invention can be improved by inclining a portion of the absorption volume forming the edge of the absorption orifice inward in relation to the absorption volume. Furthermore, similar to the cone described above which is the opposite of the absorption orifice, the inwardly inclined edge around the absorption orifice also helps ensure that the reflected electromagnetic radiation returns reliably to the absorption volume. Thus, in this embodiment of the detector according to the present invention, the ideal case described above, of complete absorption of incident electromagnetic radiation within the absorption volume, can be achieved relatively easily.

[0053] Preferably, the detector according to the present invention has both a cone-shaped section opposite the absorption orifice and an inclined edge surrounding the absorption orifice.

[0054] Another embodiment of the detector according to the present invention can be characterized in that the detector has an aperture having an aperture opening, the aperture positioned upstream in relation to the sensor element along the assumed and / or determined incident direction of the electromagnetic radiation to be measured. Such an aperture can help define the solid angle that can be measured by the detector according to the present invention. Furthermore, to improve the definition of the solid angle, two or more apertures can be used, each aligned and stacked upstream along the assumed and / or determined incident direction. Preferably, the aperture is sized and configured such, for example, that the source surface illuminated by the electromagnetic radiation source is visible from the viewpoint of the detector, and therefore, the electromagnetic radiation reflected on the source surface can reach the detector. In addition, electromagnetic radiation originating from other locations in the vacuum chamber can be blocked by the aperture, thus improving the overall accuracy of the measurement of the detector according to the present invention.

[0055] According to a further improved embodiment of the detector according to the present invention, the size of the aperture opening is adapted to the absorbing body, and particularly to the absorbing orifice, such that electromagnetic radiation arriving through the aperture opening is incident on the absorbing surface of the absorbing body, particularly through the absorbing orifice. In this embodiment, the aforementioned limitations on the field of view of the detector are further improved. Since the aperture opening and the absorbing body, particularly the absorbing orifice, are constructed in a mutually adapted state, it can be ensured that all electromagnetic radiation arriving through the aperture orifice can be recorded by the detector. This makes it possible to avoid, or at least minimize, the loss of information.

[0056] Multiple consecutive apertures can be used to further restrict and optimize the field of view. This is particularly useful in the case of powerful sources located close together that need to be measured at a large distance from the source.

[0057] In addition, the detector according to the present invention can be improved by having a shielding element, which extends along the assumed incidence direction of the electromagnetic radiation to be measured between the aperture and the absorption body. Together with the aperture, the shielding element forms a volume in front of the detector that is accessible only in the case of electromagnetic radiation arriving through the aperture orifice. Scattered electromagnetic radiation that completely misses the aperture and nevertheless occurs on the absorption body is blocked by the shielding element. This allows the field of view of the detector to be defined with improved accuracy.

[0058] Furthermore, in another improved embodiment of the detector according to the present invention, the shielding element extends further along the assumed incident direction of electromagnetic radiation along the absorption body. However, electromagnetic radiation incident on the absorption body away from the absorption surface can accumulate energy within the absorption body, which can distort the results measured by the detector. The shielding element extending further along the absorption body covers the absorption body and blocks all incoming electromagnetic radiation. Thus, distortion of the detector's measurements can be avoided, or at least minimized.

[0059] In another preferred embodiment, the detector according to the present invention can be characterized in that the detector has two or more sensor elements, thereby being adjacent to each other and thermally discoupled. As already mentioned above, during evaporation, the source surface may change its spatial shape, and in particular, the source surface may establish a convex or concave shape. Furthermore, this spatial shape of the source surface will affect the measurement results of the detector, as some of the reflected electromagnetic radiation will simply miss the main detector and / or other parts may be focused in the direction of the detector. By providing two or more sensor elements in the detector, a relatively accurate measurement of the distribution of reflected electromagnetic radiation can be obtained. Specifically, it is possible to detect even changes in the spatial shape and / or morphology of the source surface, because these changes will result in a detectable difference in the distribution of reflected electromagnetic radiation measured by the two or more sensor elements. By providing these two or more thermally discoupled sensor elements, independent measurements of each sensor element can be provided. The configuration of adjacent sensor elements ensures that the gap between sensor elements through which reflected electromagnetic radiation escapes the detector is minimized.

[0060] In addition, the detector according to the present invention can be improved by configuring two or more sensor elements in a rotationally symmetric pattern, as rows, or as a matrix, within a plane that is perpendicular, or at least fundamentally perpendicular, to the assumed and / or determined incident direction of the electromagnetic radiation being measured. Various patterns allow for the adaptation of the detector to different measurement purposes. For example, a rotationally symmetric pattern allows for the identification of focusing issues in the electromagnetic radiation provided by an electromagnetic radiation source, and thus, a configuration in rows is particularly useful for detecting misalignment between this electromagnetic radiation and the source surface. A matrix, in particular when multiple sensor elements are used, allows for more detailed measurement of the distribution of electromagnetic radiation reflected on the source surface.

[0061] A further improved embodiment of the detector according to the present invention provides a plane in which two or more sensor elements are perpendicular to, or at least fundamentally perpendicular to, the assumed and / or determined incident direction of the electromagnetic radiation being measured, and have the following shape Rectangle, Square, Circle, Circular Ring, Circular Ring Array Having one of these, or being able to have one.

[0062] This list is not exhaustive and can be expanded by further suitable shapes. Specifically, according to the configuration patterns of two or more sensor elements described above, the shapes of individual sensor elements selected in a state that conforms to the current applied pattern allow for a compact and continuous configuration of individual sensor elements without avoidable gaps between separate sensor elements.

[0063] Furthermore, the detector according to the present invention can be characterized in that the detector has components for forming an absorption body in a vacuum feedthrough. This particularly preferred embodiment of the detector according to the present invention allows the detector to be placed directly in and / or inside the vacuum feedthrough of a vacuum chamber. For example, all connections, such as the coolant channels of the sensor element and the inlet and outlet ports of the electrical connections, are accessible from outside the vacuum chamber. Within the vacuum chamber, basically only the absorption body is arranged, and if present, apertures and / or shielding elements. These elements can be provided in embodiments having the capability for extremely high vacuum. Thus, mutual degradation of parts of the detector and the reaction atmosphere in the vacuum chamber can be avoided.

[0064] According to a further improved embodiment of the detector according to the present invention, the components include a positioning element for changing the position of the absorbent body in relation to the vacuum feedthrough. The possibility of changing the position of the absorbent body within the vacuum chamber can be used, for example, to replace the source material and / or target material. This makes it possible to avoid interference by the detector, particularly by the absorbent body, with such replacement procedures. Specifically, after the completion of the procedure, the absorbent body can be reconfigured near the source element to improve the measurement capability of the detector according to the present invention by expanding the covered solid angle.

[0065] According to a third aspect of the present invention, the objective is satisfied by a system for thermal evaporation by electromagnetic radiation, comprising an electromagnetic radiation source providing electromagnetic radiation, a vacuum chamber containing a reaction atmosphere, and a main detector for measuring electromagnetic radiation, wherein the source material and the target material to be coated are arranged within the vacuum chamber, the electromagnetic radiation source is configured such that its electromagnetic radiation is incident on the source surface of the source material at a predetermined angle, preferably 45°, for thermal evaporation and / or sublimation of the source material below a plasma threshold, and the main detector for measuring electromagnetic radiation is configured such that the electromagnetic radiation reflected from the source surface reaches the main detector, and the system according to the third aspect of the present invention is adapted to perform the method according to the first aspect of the present invention. Accordingly, all the features and advantages detailed in relation to the method according to the first aspect of the present invention can also be provided by the system according to the third aspect of the invention adapted to perform the method according to the first aspect of the present invention.

[0066] Preferably, the system according to the present invention can be improved by constructing at least the main detector, preferably all detectors for electromagnetic radiation, according to a second aspect of the invention. In this particular embodiment, all the features and advantages detailed in relation to the detectors according to the second aspect of the invention can also be provided by a system according to a third aspect of the invention having at least one detector according to the second aspect of the invention.

[0067] The present invention will be further described below with reference to the embodiments shown in the attached drawings. The following drawings are shown. [Brief explanation of the drawing]

[0068] [Figure 1] This is a system according to the present invention. [Figure 2] This is a first possible embodiment of the detector according to the present invention. [Figure 3] It is an absorbent body with an absorption volume. [Figure 4] This is one embodiment of a detector according to the present invention having two sensor elements. [Figure 5] This is a configuration pattern for sensor elements. [Figure 6] It is a kinetic source element. [Figure 7] This is a cross-section of electromagnetic radiation adapted to the cross-section of the source surface. [Figure 8] This is a system according to the present invention having a first state of incident electromagnetic radiation. [Figure 9] This is a system according to the present invention that has a second state of incident electromagnetic radiation. [Figure 10] This is a system according to the present invention that has a third state of incident electromagnetic radiation. [Figure 11] This is a system according to the present invention having a fourth state of incident electromagnetic radiation. [Figure 12] This is a source element provided as a rod. [Modes for carrying out the invention]

[0069] Figure 1 shows the main components of a system 10 for the thermal evaporation of a source material 20 by electromagnetic radiation 120 according to the present invention. The source material 20 is placed in a vacuum chamber 12, which in turn confines the reaction atmosphere 16. The vacuum chamber 12 itself is shown only in its adjacent state to a vacuum feedthrough 14. An electromagnetic radiation source 110 is located in one side of the vacuum feedthrough 14, and a detector 40 according to the present invention is located in the other side.

[0070] During the operation of system 10, the electromagnetic radiation source 110 provides electromagnetic radiation 120 that is guided and incident on the source surface 22 of the source material 20. The source material 20 absorbs a portion of the electromagnetic radiation 120, and therefore a portion of the source material 20 evaporates or sublimes, as shown by the dashed circular line in Figure 1. On the opposite side of the source material 20 is the target material 18. The evaporated source material 20 reaches the target material 18 and forms a coating on the surface of the target material 18.

[0071] The remaining portion of the electromagnetic radiation 120 is reflected on 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, it is possible to position the detector 40 in the assumed and / or determined incident direction 122 of the reflected electromagnetic radiation 120. Also, as described above for the electromagnetic radiation source 110, the detector, in particular its absorption body 52, can be positioned in the vacuum feedthrough 14 of the vacuum chamber 12.

[0072] The detector 40 according to the present invention functions as a bolometer. Electromagnetic radiation 120 is incident on the absorbing surface 60 of the absorbing body 52 and will be at least partially absorbed. As depicted, the absorbing surface 60 faces the source surface 22 and is therefore also covered by the evaporated source material 20, as depicted in Figure 1. Thus, after a short accumulation time, the absorbing surface 60 will have the same or at least similar absorption and reflection properties as the source surface 22.

[0073] The aforementioned energy storage within the absorption body 52 will result in a change in the temperature of the absorption body 52 or at least an increased need for cooling. By measuring the temperature or its changing behavior, the evaporation rate and / or flow distribution of the source material 20 that evaporates or sublimes due to the incident electromagnetic radiation 120 can be determined.

[0074] Figure 2 shows a cross-section of a possible embodiment of the detector 40 according to the present invention. The detector 40 can be used, for example, as the main detector 100, a first further detector 102, and / or a second further detector 104 in both the method and system 10 according to the present invention (see Figures 8 to 11).

[0075] The detector 40 has a single sensor element 50 having an absorbent body 52 made of a metal having high thermal conductivity, preferably copper or aluminum. The component 40 allows the absorbent body 52 to be located in the vacuum feedthrough 14 of the vacuum chamber 12 of the system 10 according to the present invention. Specifically, the component 42 has a positioning element 44 for changing the actual position of the absorbent body 52 in the reaction atmosphere 16 of the vacuum chamber 12. Thus, it is possible to provide, for example, the motion of other elements of the system 10 arranged in the vacuum chamber 12 as a source material 20 without any interference generated by the detector 40, see Figure 1 for this.

[0076] The detector 40 according to the present invention is based on the principle of a bolometer. Electromagnetic radiation 120 is incident on the absorption surface 60 of the absorption body 52 and is at least partially absorbed. This energy storage can be measured by measuring the absolute temperature of the absorption body or the change in its temperature.

[0077] To this end, the illustrated detector 40 according to the present invention implements two different measurement methods and individual sensing elements 70. Each method can be used separately to measure temperature and its changes. However, by combining the two methods described below, relatively high accuracy can be provided.

[0078] In the first method, the absorption body 52 has a cooling system 80 for active cooling. Coolant 84 flows through a cooling duct 82 through the absorption body 52, thereby absorbing the energy accumulated in the absorption body 80 by the incident electromagnetic radiation 120. As shown in Figure 2, a flow sensor 72 measures the flow rate of the coolant 84 and a temperature sensor 74 measures the temperature of the coolant 84 at both the inlet and outlet ports of the cooling duct 82, respectively. In short, these combined measurements allow for an accurate determination of the amount of energy accumulated in the absorption body 52.

[0079] In the second method, a temperature sensor 74, preferably a thermocouple element 74, is positioned within the bore 54 of the absorption body 52, particularly in the vicinity of the absorption surface 60. As described above, the energy deposited by the electromagnetic radiation 120 incident on the absorption surface 60 generates a temperature rise in the absorption body 52. ​​The thermocouple 76 positioned within the absorption body 52 in the vicinity of the absorption surface 60 can be measured as an absolute temperature or as a temperature change. Thus, this measurement method also allows for the accurate determination of the amount of energy accumulated within the absorption body 52.

[0080] Figure 3 shows a cross-section of a preferred, rotationally symmetric embodiment of the detector 40 according to the present invention, particularly of its absorption surface 60. According to this embodiment, the absorption body 52 of the illustrated sensor element 50 has a hollow absorption volume 56 at its end facing the incident direction 122 of the electromagnetic radiation 120 to be measured. This absorption volume 56 has a single opening, i.e., an absorption orifice 62, which allows the incident electromagnetic radiation 120 to enter the absorption volume 56. The inner side wall 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 shown by the arrows in Figure 3, thereby absorbing a portion of the energy of the incident electromagnetic radiation 120 at each reflection. Ideally, the electromagnetic radiation 120 is captured within the absorption volume 56 and consequently completely absorbed by the absorption surface 60. To improve the probability of this ideal case, a portion of the sidewall forming the edge 64 surrounding the absorption orifice 62 is inclined inward in relation to the absorption volume 56. This inwardly inclined surface offers the further advantage of avoiding reflections that return electromagnetic radiation incident on these surfaces back to the direction of incidence. In addition, a portion of the absorption surface 60 located on the opposite side of the absorption orifice 62 is shaped conically, with the tip of the cone pointing towards the absorption orifice 62.

[0081] Figure 4 shows a detector 40 having two sensor elements 50. The sensor elements 50 are positioned adjacent to each other and are thermally uncoupled. Each sensor element 50 has its own absorption body 52 and absorption surface 60. The rest of the sensor elements 50 are not shown. If required, providing two or more sensor elements 50 can provide relatively detailed information about the absorbed electromagnetic radiation 120, for example, to determine the evaporation rate and / or flow distribution of the evaporated source material 20 (not shown).

[0082] In addition, two stacked and aligned apertures 90 are positioned upstream of each individual sensor element 50. The aperture openings 92 contain a solid angle for receiving the individual sensor elements 50. Crosstalk between the sensor elements 50, indicated by the dashed arrows, can be avoided. Furthermore, shielding elements 94 are positioned between the apertures 90 and the absorption bodies 52, and optionally along the individual aperture bodies 52. These shielding elements 94 further reduce the aforementioned crosstalk. On the other hand, electromagnetic radiation 120 incident on the side surfaces of the absorption bodies 52 is blocked, preventing distortion of the measurement results.

[0083] As mentioned in relation to Figure 4, the detector 40 according to the present invention may have two or more sensor elements 50. Figure 5 shows some examples of the shape and configuration patterns of the sensor elements 50 and their absorption surfaces 60. In one limitation, it is clear that other configurations are possible, such as a high-resolution pixel array similar to that of an electronic camera. If necessary, the most suitable of the different configuration patterns can be selected in relation to the measurement objectives of the detector 40, such as determining the evaporation rate and / or flow distribution of the evaporated source material 20.

[0084] The upper left panel of Figure 5 shows a standard shape with a simple circular active surface.

[0085] The motion of the electromagnetic radiation 120 in the incident direction 122 can be detected by four quadrants, as shown in the upper right panel. Here, the sensor element 50 is shaped as a square and is configured so that motion in the horizontal and vertical directions can be detected mainly along its diagonal while keeping the number of sensor elements 50 small.

[0086] In the lower left panel of Figure 5, a third configuration is shown, which has a sensor element 50 forming a rotationally symmetrical pattern of a circular ring. This pattern is most sensitive to the focusing or defocusing of electromagnetic radiation 120 provided by the electromagnetic radiation source 110.

[0087] Both position and defocus, although only in the vertical direction in this case, can be detected by a stripe configuration of rectangularly shaped sensor elements 50, such as those shown in the lower right panel of Figure 5. This may be preferable because electromagnetic radiation 120 reflected on the source surface 22 at an incident direction 122 of approximately 45° is relatively more strongly affected in the plane containing the incident and reflected beams than radiation perpendicular to itself.

[0088] Figure 6 shows the basic elements of the system 10 according to the present invention, namely the electromagnetic radiation source 110, the source material 20, and the detector 40, in particular the main detector 100. As the electromagnetic radiation 120 light, laser light with a wavelength of 100 nm to 1400 nm is used. The method according to the present invention will be described below.

[0089] In the first step a) of the method according to the present invention, electromagnetic radiation 120 is provided by an electromagnetic radiation source 110. The electromagnetic radiation 120 is incident on the source surface 22 of the source material 20, preferably at an angle of 45°, and thermally evaporates or sublimes the source material 20 below the plasma threshold.

[0090] In a subsequent step b) of the method according to the present invention, the electromagnetic radiation 120 reflected from the source surface 22 is measured by the main detector 100 of the system 10. For this purpose, the main detector is appropriately positioned within a vacuum chamber 12 (not shown).

[0091] In the subsequent step c), the measurement data obtained in step b) of the method according to the present invention is analyzed. As the response function of the detector 40, the properties of the incident electromagnetic radiation 120 and the desired evaporation rate, and therefore the required absorbed electromagnetic radiation 120 are known, so the remaining reflected portion of the electromagnetic radiation 120 can also be determined. By comparing the measurement of the main detector 100 in step b) with the prediction in relation to the reflected electromagnetic radiation 120, it is possible to estimate whether the desired evaporation rate is satisfied.

[0092] If the actual evaporation rate estimated in step c) differs from the desired evaporation rate, the evaporation rate can be adjusted in the final step d) of the method according to the present invention to satisfy the specifications. This adjustment can be provided by various means.

[0093] As shown in Figure 6, by moving the source element 20 perpendicular and / or parallel to the source surface 22, the illumination of the source surface 22 by the incident electromagnetic radiation 120 can be altered, in particular, shifted, enlarged, and scaled down, respectively. As a result, the evaporation rate will increase and decrease, respectively. For this purpose, the source material 20 is preferably provided as a self-supporting source element 24, such as a rod 30. A holding structure 28 can be used to provide the aforementioned motion of the source surface 22.

[0094] Alternatively, or in addition to this, and as shown in Figure 7, the size and / or shape of the cross-section of the electromagnetic radiation 120 provided by the electromagnetic radiation source 110 can also be adjusted. By changing the size and / or shape of the cross-section of the electromagnetic radiation 120, the fit of the incident electromagnetic radiation 120 to the size and / or shape of the source surface 22 can be changed, in particular, improved. Also, relatively good, preferably complete, illumination of the source surface 22 by the electromagnetic radiation 120 results in an increased evaporation rate. As depicted, the electromagnetic radiation 120 can be provided with, for example, an elliptical cross-section to match the circular cross-section of the source surface 22 provided as a molten pool of the source material 20 confined in the crucible 32, thereby making the crucible 32 at least partially transparent to the electromagnetic radiation 120.

[0095] Furthermore, the power of electromagnetic radiation 120, particularly its power density, can be adjusted. Since relatively high power results in relatively large energy storage, the power of electromagnetic radiation 120 directly affects the evaporation rate.

[0096] In short, the method according to the present invention described above allows for active adjustment of the evaporation rate during the operation of individual evaporation systems 10 based on actual measurements. Thus, the evaporation rate can be controlled. Consequently, the coating of the target material 18 having the source material 20 can also be improved.

[0097] Figures 8 to 11, which follow, show one embodiment of the system 10 according to the present invention, which has three detectors 40, namely a main detector 100, a first further detector 102, and a second further detector 104. As described above, the main detector 100 is configured to measure electromagnetic radiation 120 reflected on the source surface 22 in the incident direction 122. The first further detector 104 is configured to detect electromagnetic radiation 120 reflected on the side surface 26 of the source element 24, and finally, the second further detector 104 detects electromagnetic radiation 120 that has missed the source element 24, in particular the source surface 22. Various situations that occur during the operation of the illustrated system 10 will be described below.

[0098] Figure 8 shows an ideal case of the operation of system 10. The electromagnetic radiation 120 illuminates the source surface 22 and is partially reflected in the incident direction 122 to the main detector 100. The electromagnetic radiation 120 does not reach the remaining first and second further detectors 102, 104. No action is required on the holding structure 28.

[0099] Figure 9 shows the different states that occur when a portion of the incoming electromagnetic radiation 120 misses the source element 24 and reaches the second additional detector 104. Based on the measurement signal of the second additional detector 104 in combination with the reduced sensor output of the main detector 100, it can be estimated that the source surface 22 is excessively low or excessively shifted to the left in relation to the incoming electromagnetic radiation 120. This, in turn, triggers the activation of the holding structure 28, causing the source element 24 to move upward or to the right as indicated by the arrows in the figure.

[0100] Figure 10 illustrates the opposite situation, where a portion of the incoming electromagnetic radiation 120 is reflected off the side surface 26 of the source element 24 and reaches the first additional detector 102. Similarly, based on the measurement signal of the first additional detector 102 in combination with the reduced sensor output of the main detector 100, it can be estimated that the source surface 22 is excessively high or excessively to the right in relation to the incoming electromagnetic radiation 120. This would trigger the activation of the holding structure 28, causing the source element 24 to move downward or to the left as indicated by the arrows in the figure.

[0101] Figure 11 shows another possible static state during the operation of the system 10 according to the present invention. In this state, the incoming electromagnetic radiation 120 is outshining the source surface 22. In other words, the cross-section of the incoming electromagnetic radiation 120 is greater than the cross-section of the source surface 22. In this case, the electromagnetic radiation 120 reaches all three detectors 40, namely the main detector 100 and both additional detectors 102 and 104. As long as both additional detectors 102 and 104 are detecting a predetermined or at least a certain amount of electromagnetic radiation 120, full illumination of the source surface 22 can be assumed. If one of the additional detectors 102 and 104 ceases detecting the electromagnetic radiation 120, the position of the source element 24 can be changed accordingly by triggering the holding structure 28 as described above.

[0102] By relating the relative intensities of the detectors, changes in incoming electromagnetic radiation can be detected as proportional changes in the signals of the pair of detectors or all three. This allows for fluctuations and control of the overall magnitude of electromagnetic radiation without triggering corrective motion of the source element 24, and thereby independent control and optimization of both quantities.

[0103] Similarly, the focusing and defocusing of electromagnetic radiation result in non-proportional intensity fluctuations between the main detector 100 and the additional detectors 102 and 104, thereby discriminating the positions of the focal and source elements 24 of the electromagnetic radiation 120, and thus enabling independent control.

[0104] As the first additional detector 102 detects the electromagnetic radiation 120 reflected on the side surface 26 of the source element 24, this side surface 26 is preferably provided in a flat state. This is depicted in Figure 11. The illustrated source element 24 is provided as a self-supporting rod 30 composed of source material 20. Preferably, the flat side surface 26 is oriented perpendicular to both the source surface 22 and the incoming electromagnetic radiation 120 provided by the electromagnetic radiation source 110 (not shown). [Explanation of Symbols]

[0105] 10 Systems 12 Vacuum Chamber 14. Vacuum feedthrough 16 Reaction atmosphere 18 Target materials 20 Sauce Ingredients 22 Source surface 24 Source Elements 26 Side surface 28 Retention structure 30 rods 32 crucibles 40 detectors 42 Components 44 Positioning elements 50 sensor elements 52 Absorbent Body 54 Bore 56 Absorption capacity 58 Side wall 60 Absorption surface 62 Absorption orifice 64 rim 70 Thermal sensing elements 72 Flow Sensor 74 Temperature Sensor 76 Thermocouple elements 80 Cooling System 82 Cooling duct 84 Coolant 90 Aperture 92 Aperture opening 94 Shield elements 100 Main detectors 102 First further detector 104 A second further detector 110 Electromagnetic radiation sources 120 Electromagnetic radiation 122 Incident direction

Claims

1. A method for controlling the evaporation rate of a source material (20) in a system (10) for thermal evaporation by electromagnetic radiation (120), The system (10) includes an electromagnetic radiation source (110) that provides electromagnetic radiation (120), a vacuum chamber (12) that houses a reaction atmosphere (16), and main detectors (40, 100) that measure the electromagnetic radiation (120). The source material (20) and the target material (18) to be coated are arranged inside the vacuum chamber (12). The electromagnetic radiation source (110) is configured such that its electromagnetic radiation (120) is incident at a predetermined angle on the source surface (22) of the source material (20) for thermal evaporation and / or sublimation of the source material (20) below the plasma threshold. The main detectors (40, 100) for measuring electromagnetic radiation (120) are configured such that the electromagnetic radiation (120) reflected from the source surface (22) reaches the main detectors (40, 100), and further, The aforementioned source material (20) is provided by the source element (24), The source surface (22) is positioned on the source element (24) in a manner that allows access to the electromagnetic radiation (120), the source element (24) is positioned within a holding structure (28) and is movable by the holding structure (28) perpendicular to the source surface (22), The aforementioned method, a) The step of providing the electromagnetic radiation (120) by the electromagnetic radiation source (110), b) A step of measuring the electromagnetic radiation (120) reflected on the source surface (22) by the main detector (40, 100), c) A step of analyzing the measured data obtained in step b), d) Adjusting the evaporation rate based on the results of the analysis in step c) by moving the source element (24) in relation to the electromagnetic radiation (120), and / or adjusting the power of the electromagnetic radiation (120), and / or adjusting the size and / or shape of the cross-section of the electromagnetic radiation (120), A method in which, in step b), the main detector (40, 100) having two or more sensor elements (50) is used, the two or more sensor elements (50) are adjacent to each other and thermally discoupled.

2. The method according to claim 1, wherein in step d), the source element (24) is moving perpendicular and / or parallel to the source surface (22).

3. The method according to claim 1 or 2, wherein the source element (24) is provided as a self-supporting structure having a source material (20) including the source surface (22) disposed at the upper end of the source element (24).

4. The source element (24) is provided as a rod (30), The rod (30) is provided with a circular or at least fundamentally circular rod (30) cross-section. The electromagnetic radiation (120) is provided with an elliptical beam cross-section. The method according to claim 3, wherein the cross section of the rod (30) and the cross section of the beam are selected in a mutually compatible state.

5. The source element (24) has a crucible (34) containing the source material (20), The method according to claim 1 or 2, wherein the crucible (34) is transparent or at least partially transparent with respect to the electromagnetic radiation (120) when the source surface (22) is positioned within the crucible (34).

6. The method according to any one of claims 1 to 5, wherein the electromagnetic radiation (120) light used is laser light having a wavelength of 100 nm to 1400 nm.

7. The method according to any one of claims 1 to 6, wherein in step b), a first further detector (40, 102) is used to measure electromagnetic radiation (120) reflected on a side surface (26) of the source element (24) that is different from the source surface (22), so that the data measured by the first further detector (40, 102) is used in steps c) and d).

8. The method according to claim 7, wherein the side surface (26) of the source element (24) is provided in a flat state.

9. The method according to claim 8, wherein the flat side surface (26) is oriented perpendicular to a plane covered by the direction of the electromagnetic radiation (120) incident on and reflected from the source surface (22).

10. The method according to any one of claims 1 to 9, wherein in step b), a second additional detector (40, 104) is used to measure electromagnetic radiation (120) that has escaped the source surface (22) of the source element (24), and the data measured by the second additional detector (40, 104) is used in steps c) and d).

11. A detector (40) for measuring electromagnetic radiation (120) reflected from a source surface (22), having a sensor element (50) having an absorption body (52), The absorbing body (52) has an absorbing surface (60) that absorbs the electromagnetic radiation (120) at least partially, The sensor element (50) further includes a thermal sensing element (70) that measures the temperature of the absorption body (52) in order to detect the absolute temperature and / or temperature change generated within the absorption body (52) due to the absorbed electromagnetic radiation (120). The absorbent body (52) has a cooling system (80) for active cooling of the absorbent body (52), The cooling system (80) has at least one cooling duct (82) within the absorption body (52) for the flow of coolant (84) through the absorption body (52), The heat sensing element (70) includes a flow sensor (72) for measuring the flow of the coolant (84) through the cooling duct (82) in the absorption body (52), and a temperature sensor (74) for measuring the absolute temperature of the coolant (84) and / or the temperature change of the coolant (84) induced by the flow through the cooling duct (82) in the absorption body (52). The detector has two or more of the sensor elements (50), A detector (40) in which two or more of the aforementioned sensor elements (50) are adjacent to each other and thermally discoupled.

12. The detector (40) according to claim 11, wherein one or more detectors can be used in the method of any one of claims 1 to 10 as a main detector (40, 100) and / or as a first further detector (40, 102) and / or as a second further detector (40, 104).

13. The detector (40) according to claim 11 or 12, wherein the absorbing surface (60) absorbs light having a wavelength of 100 nm to 1400 nm.

14. The heat sensing element (70) has a temperature sensor (74) positioned within the bore (54) of the absorption body (52), The detector (40) according to any one of claims 11 to 13, wherein the bore (54) is terminated within the absorption body (52).

15. The detector (40) according to any one of claims 11 to 14, wherein the absorption body (52) is made of metal.

16. The absorbent body (52) has a hollow absorbent volume (56) sealed inside at one end, and as a result, the inner side wall (58) of the absorbent volume (56) forms the absorbent surface (60). The detector (40) according to any one of claims 11 to 15, wherein the absorption volume (56) has an absorption orifice (62), thereby allowing the absorption orifice (62) to be aligned with the assumed and / or determined incident direction (122) of the electromagnetic radiation (120) to be measured.

17. The absorption surface (60) is partially formed into a conical shape within the absorption volume (56). The detector (40) according to claim 16, wherein the cone of the conically shaped absorption surface (60) faces the absorption orifice (62).

18. The detector (40) according to claim 16 or 17, wherein the portion of the absorption volume (56) forming the edge (64) of the absorption orifice (62) is inclined inward in relation to the absorption volume (56).

19. The detector has an aperture (90) having an aperture opening (92), The detector (40) according to any one of claims 11 to 18, wherein the aperture (90) is positioned upstream of the sensor element (50) in relation to the assumed and / or determined incident direction (122) of the electromagnetic radiation (120) to be measured.

20. The detector (40) according to claim 19, wherein the size of the aperture opening (92) is adapted to the absorbing body (52) such that electromagnetic radiation (120) arriving through the aperture opening (92) is incident on the absorbing surface (60) of the absorbing body (52).

21. The detector has a shielding element (94), The detector (40) according to claim 19 or 20, wherein the shielding element (94) extends between the aperture (90) and the absorbing body (52) along the assumed incident direction (122) of the electromagnetic radiation (120) to be measured.

22. The detector (40) according to claim 21, wherein the shielding element (94) further extends along the absorbing body (52) along the assumed incident direction (122) of the electromagnetic radiation (120).

23. The detector (40) according to any one of claims 11 to 22, wherein the two or more sensor elements (50) are arranged in a rotationally symmetric pattern, in rows, or in a matrix within a plane perpendicular to or at least fundamentally perpendicular to the assumed and / or determined incident direction (122) of the electromagnetic radiation (120) to be measured.

24. The detector (40) according to any one of claims 11 to 23, wherein the two or more sensor elements (50) have one of the shapes of a rectangle, a square, a circle, a circular ring, or a circular ring segment, in a plane perpendicular or at least fundamentally perpendicular to the assumed and / or determined incident direction (122) of the electromagnetic radiation (120) to be measured.

25. The detector (40) according to any one of claims 11 to 15, wherein the detector has a component (42) for forming the absorption body (52) in a vacuum feedthrough (14).

26. The detector (40) according to claim 25, wherein the component (42) has a positioning element (44) for changing the position of the absorption body (52) in relation to the vacuum feedthrough (14).

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