Detector for measuring electromagnetic radiation reflected on a source surface, method for controlling a flux distribution of evaporated source material and system for thermal evaporation with electromagnetic radiation

Abstract

This invention relates to a detector (40) for measuring electromagnetic radiation (120) reflected onto a source surface (22), comprising a sensor element (50) having an absorber (52) including an absorbing surface (60) for absorbing at least a portion of the electromagnetic radiation (120), wherein the sensor element (50) further includes a thermal element (70) for measuring the temperature of the absorber (52) to detect the absolute temperature and / or temperature change caused by the electromagnetic radiation (120) absorbed by the absorber (52). Furthermore, this invention relates to a method for controlling the flux distribution (30) of an evaporation source material (20) in a system (10) using electromagnetic radiation (120) for thermal evaporation. The system (10) includes an electromagnetic radiation source (110) providing electromagnetic radiation (120), a vacuum chamber (12) containing a reaction environment (16), and a detector (40) for measuring the electromagnetic radiation (120). The source material (20) and the target material (18) to be vaporized are placed within the vacuum chamber (12), and the radiation source is positioned such that its electromagnetic radiation (120) strikes the source surface (22) of the source material (20) at an angle, so that the thermal evaporation and / or sublimation of the source material (20) is below the plasma threshold. The detector (40) for measuring the electromagnetic radiation (120) is positioned such that the electromagnetic radiation (120) reflected from the source surface (22) reaches the detector (40). Furthermore, this invention relates to a system (10) for thermal evaporation using electromagnetic radiation (120), which includes the detector (40) according to the invention and is applicable to the method according to the invention.

Description

[Technical Field]

[0001] The present invention relates to a detector for measuring electromagnetic radiation reflected from a source surface. The detector includes a sensing element having an absorber, the absorber including an absorbing surface capable of absorbing at least a portion of the electromagnetic radiation; wherein the sensing element further includes a thermal element for measuring the temperature of the absorber, for detecting absolute temperature and / or temperature changes originating from the electromagnetic radiation absorbed by the absorber.

[0002] Furthermore, the present invention relates to a method for controlling the flux distribution of an evaporation source material in a system for thermal evaporation using electromagnetic radiation. The system includes an electromagnetic radiation source that provides electromagnetic radiation, a vacuum chamber containing a reaction atmosphere, and a detector for measuring electromagnetic radiation. The source material and the target material to be vaporized are placed in the vacuum chamber, and the radiation source is positioned such that its electromagnetic radiation strikes the source surface of the source material at an angle, preferably 45 degrees, so that the thermal evaporation and / or sublimation of the source material is below the plasma threshold. The detector for measuring electromagnetic radiation is positioned so that the electromagnetic radiation reflected from the source surface reaches the location of the detector.

[0003] Furthermore, the present invention relates to a system for thermal evaporation using electromagnetic radiation, comprising an electromagnetic radiation source providing electromagnetic radiation, a vacuum chamber containing a reaction environment, and a detector for measuring electromagnetic radiation; wherein the source material and the target material to be vaporized are placed in the vacuum chamber, and the radiation source is positioned such that its electromagnetic radiation is at an angle, preferably 45 degrees, impacting the source surface of the source material, so that the thermal evaporation and / or sublimation of the source material is below the plasma threshold; and wherein the detector for measuring electromagnetic radiation is positioned such that the electromagnetic radiation reflected from the source surface reaches the location of the detector. [Previous Technology]

[0004] The use of electromagnetic radiation, particularly laser light with wavelengths in the visible, infrared, or ultraviolet range, for evaporating source materials is known. Such laser evaporation systems allow for the deposition of a thin film of a bulk source material by heating its center from the front using a continuous-wave laser at low pressure. For example, silicon is melted at the temperature necessary to achieve the desired flux for evaporation, forming a molten pool within the solid portion of the source material. This solid portion of the source material thus forms a crucible of liquid silicon, allowing for high heating and cooling rates due to thermal expansion mismatch between the source material and the crucible. This also avoids contamination of the source material by crucibles made of different materials. Alternatively, crucibles made of materials different from those to be evaporated can also be used.

[0005] However, as the source material is depleted by the impact of electromagnetic radiation, the source surface also deforms, for example, the molten pool develops concave surfaces and / or sublimation penetrates deeper into the source material. The flux distribution and evaporation rate of the evaporating material, which are directly affected by the shape of the source surface, are therefore inherently unstable.

[0006] Generally, two main cases can be distinguished. In the case of localized sublimation or evaporation at a recess, due to the attenuation of the radioactive intensity of the electromagnetic radiation beam and the thermal gradient away from the maximum intensity, the sublimation or evaporation rate of the electromagnetic radiation at the center of that point reaches its maximum value, thus forming a recess at that point or under the electromagnetic radiation. Moving outward from the deepest point of this recess, the surface element tilts inward toward the source symmetry axis, thereby contributing more to the center of the flux distribution. Such focusing of the flux distribution can even be advantageous, especially when small objects need to be deposited at a greater distance. However, once the recess of the source surface becomes too deep, the evaporation or sublimation from the sidewall surface element will tilt too much, and the flux distribution will become out of focus again. In addition, the overly tilted sidewall may block part of the pre-deposited mole, resulting in strong thickness inhomogeneity.

[0007] The second main case is a locally convex sublimation or evaporation surface. Here, the surface element away from the source axis of symmetry is tilted outward, which immediately results in more material flux distribution directly next to the sample compared to a flat surface. Such out-of-focus flux distribution may lead to a reduction in growth rate on the target substrate; thus, the amount of sublimated or evaporated source material that misses the target will be greater than in the case where the source surface is flat.

[0008] Generally, a known solution is to move the point of electromagnetic radiation on the source material in order to obtain a more uniform energy distribution and flux distribution of the evaporating source material. However, to have practical and active flux distribution control, it is necessary to reliably detect the surface curvature beneath the electromagnetic radiation point. Direct observation of the source surface using a camera is hindered by the rapid evaporation of any window on the source surface, thus hindering the observation of evaporation or sublimation flux.

[0009] Based on the above reasons, an object of the present invention is to provide an improved detector for measuring electromagnetic radiation reflected from a source surface, an improved method for controlling the flux distribution of an evaporation source material, and a system for thermal evaporation using electromagnetic radiation that does not suffer from the disadvantages of the prior art. In particular, an object of the present invention is to provide a detector, a method, and a system that allows for simple and cost-effective control of the flux distribution of an evaporation source material in a system for thermal evaporation using electromagnetic radiation, wherein, specifically in closed-loop control, the flux distribution is preferably adjustable in response to spatial variations in shape, size, and orientation, especially in closed-loop control. [Summary of the Invention]

[0010] The object of the present invention is achieved by the individual claims. Specifically, it is achieved by the detector according to claim 1, the method according to claim 18, and the system according to claim 29. The supplementary claims are used to describe preferred embodiments of the invention. Where technically reasonable, the details and advantages of the detector corresponding to the first aspect of the invention also relate to the method according to the second aspect of the invention and the system according to the third aspect of the invention, and vice versa.

[0011] According to a first aspect of the present invention, the object of the present invention is achieved by a detector for measuring electromagnetic radiation reflected from a source surface; the detector includes a sensing element having an absorber; the absorber includes an absorbing surface for absorbing at least a portion of the electromagnetic radiation; wherein the sensing element further includes a thermal element for measuring the temperature of the absorber to detect the absolute temperature and / or temperature change caused by the absorbed electromagnetic radiation in the absorber, wherein the thermal element includes a temperature sensor, particularly a thermocouple element, disposed in an inner hole in the absorber, wherein the inner hole terminates in the absorber and is preferably adjacent to the absorbing surface.

[0012] The detector according to the invention can be used in systems where electromagnetic radiation is used for thermal evaporation. Specifically, such a detector can be used to measure, for example, electromagnetic radiation reflected from the surface of a source material.

[0013] The electromagnetic radiation to be measured strikes the absorber, specifically the absorbing surface, and at least a portion of it is absorbed by the absorbing surface. In other words, at least a portion of the energy of the electromagnetic radiation is deposited into the absorber. Therefore, individually measuring and monitoring the temperature of the absorber allows determination of the energy deposited into the absorber and thus of the amount of electromagnetic radiation striking the absorbing surface.

[0014] At least a portion of the absorbing surface faces the source surface. Therefore, the absorbing surface is deposited with evaporated or sublimated source material. After a sufficiently long deposition period, the detector thus acquires the same characteristics as the source, meaning it has a constant absorptivity and reflectivity, just like the source.

[0015] The absorbing surface can, for example, be perpendicular to the assumed impact direction of the electromagnetic radiation to be measured. Since only a portion of the impact electromagnetic radiation will be absorbed, the remainder will be reflected back in the same direction. In a thermal evaporation system, the detector according to the invention is used to measure electromagnetic radiation reflected from a source surface, which is guided back to the source surface and can be used for a second thermal evaporation.

[0016] However, a subsequent second reflection on the source surface can guide the electromagnetic radiation back to the source and may cause interference. An embodiment with an absorbing surface having two flat blocks arranged adjacent to each other at an angle of slightly less than 90° (e.g., 89°) can solve this problem. The electromagnetic radiation can still be reflected back to the source surface, but in a less precise direction, thus missing the source. Furthermore, since the electromagnetic radiation impacting the double-absorbing surface is reflected twice, the absorption of the impacting electromagnetic radiation by the absorbing surface is doubled. Energy is deposited into the absorber, and therefore the accuracy of the measurement can be improved.

[0017] In order to measure and / or monitor the amount of energy deposited in the absorber by impact electromagnetic radiation, the absolute temperature and / or 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 an inner hole adjacent to the absorber surface within the absorber.

[0018] This inner aperture allows a temperature sensor to be arranged near the absorption surface, thereby improving the accuracy of temperature measurement. The actual temperature and / or temperature change of the absorber can be directly measured using the temperature sensor within the absorber. Therefore, the absolute value of the energy deposition caused by the electromagnetic radiation absorbed by the absorber can be determined. In particular, measurements based on the detector according to the invention, such as electromagnetic radiation reflected from the source surface, the measured distribution of electromagnetic radiation reflected from the source surface, and, hereinafter, the corresponding matching between the actual distribution of the evaporation source material and the intended distribution of the evaporation source material, can be derived and subsequently controlled.

[0019] Furthermore, the detector according to the invention is characterized by an absorbing surface that absorbs light with wavelengths between 100 nm and 1400 nm, particularly laser light. Light, particularly laser light, is suitable for a wide range of possible source materials through evaporation and / or sublimation. By providing an absorbing surface capable of absorbing light, the detector according to the invention can adapt to this particular electromagnetic radiation. Adaptation may, for example, include selecting a suitable material for the absorber having the absorbing surface. Additionally or alternatively, appropriate vapor deposition may be used for the absorbing surface to enhance light absorption.

[0020] According to another embodiment of the detector according to the invention, the absorber includes a cooling system for actively cooling the absorber, wherein the cooling system includes at least one cooling duct within the absorber for allowing a coolant (preferably water) to flow through the absorber. The cooling duct of the cooling system passes through the absorber and allows the coolant to flow through the absorber. The coolant may be a fluid, preferably water. The coolant cools the absorber by flowing through it. Preferably, the cooling system maintains the absorber at a constant temperature. Therefore, the absorber does not change its temperature and thus maintains its ability to detect impact electromagnetic radiation. Furthermore, the coolant flowing through the cooling duct in the absorber preferably absorbs any energy deposited within the absorber by impact electromagnetic radiation. The temperature of the coolant thus varies according to the amount of energy absorbed.

[0021] Therefore, the detector according to the present invention can be further improved by using a thermal element comprising a flow sensor and a temperature sensor. The flow sensor is used to measure the flow rate of coolant through the cooling pipes in the absorber, while the temperature sensor is used to measure the absolute temperature of the coolant and / or the temperature change of the coolant caused by 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 comprises two different types of sensors, namely a flow sensor and a temperature sensor. Specifically, the flow sensor measures the flow rate of coolant flowing through the cooling pipes. The temperature sensor measures the temperature of the coolant. Specifically, the temperature of the coolant is measured at at least one outlet of the cooling pipe, and even more preferably at the inlet of the cooling pipe. The outlet temperature allows for the detection of temperature changes over time, provided that coolant with a constant temperature is provided at the inlet. By additionally measuring the inlet temperature of the coolant, the measurement of relative temperature changes can be improved. In particular, by combining temperature measurement with the aforementioned flow measurement, the absolute value of energy deposition caused by the absorbed electromagnetic radiation can be determined.

[0022] This additional temperature measurement can be used to check the measurement of the temperature sensor arranged in the inner hole and / or improve the overall accuracy of the temperature measurement. In addition, if the temperature measurement based on the temperature sensor in the inner hole fails or is completely lost, the measurement of the temperature of the absorber and the measurement of the energy deposited in the absorber due to electromagnetic radiation are still possible.

[0023] Furthermore, the detector according to the invention preferably includes an absorber, which comprises, in particular, a metal, especially copper or aluminum. Using a metal as the absorber material offers several advantages. First, metals, especially copper and aluminum, have high thermal conductivity. The detector according to the invention is designed as a bolometer, which absorbs impact electromagnetic radiation and includes a sensing element to measure temperature and / or the temperature change caused by the absorption. Materials with high thermal conductivity are particularly suitable for such bolometers. Furthermore, metals are suitable materials for use under ultra-high vacuum conditions. Therefore, contamination of the ultra-high vacuum environment, which serves as the reaction environment, by the detector according to the invention can be avoided, and vice versa.

[0024] According to another preferred embodiment of the detector according to the invention, an absorption system surrounds one end of a hollow absorption volume, wherein the inner wall of the absorption volume forms an absorption surface, and wherein the absorption volume includes an absorption aperture, wherein the absorption aperture can be aligned with the assumed and / or determined impact direction of the electromagnetic radiation to be measured. As mentioned above, in most cases, the absorption surface also absorbs only a portion of the impacting electromagnetic radiation, at least a portion of the electromagnetic radiation that directly impacts the detector. In a preferred embodiment of the detector according to the invention, the absorption surface is the inner wall of a hollow absorption volume. Electromagnetic radiation impacting the detector enters the absorption volume through the absorption aperture. Within the absorption volume, the electromagnetic radiation impacts the absorption surface and is partially absorbed and partially reflected. Since this reflection occurs within an absorption volume that is preferably relatively larger than the absorption aperture, the reflected electromagnetic radiation is likely to miss the absorption aperture and impact the inner wall of the absorption volume again, in other words, impact another section of the absorption surface. Ideally, this process repeats itself until the impacting electromagnetic radiation is completely or at least substantially completely absorbed by the absorber. In this case, the energy deposited in the absorber represents the total energy of the impact's electromagnetic radiation. In particular, any vapor deposition system with an evaporation source material on the absorbing surface is therefore ineffective.

[0025] A further improved embodiment of the detector according to the present invention may include an absorbing surface partially shaped into a cone within an absorbing volume, the cone of the absorbing surface facing the absorbing aperture. The cone may be shaped as a protrusion and a recess, such that in the protrusion embodiment, the tip of the cone faces the absorbing aperture, and in the recess embodiment, the base of the cone faces the absorbing aperture. In other words, impact electromagnetic radiation passing through the absorbing aperture first impacts the cone-shaped portion of the absorbing surface. Since the cone faces the absorbing aperture, any electromagnetic radiation reflected from the side of the cone will be guided to some point in the absorbing volume and will certainly miss the absorbing aperture. Therefore, the aforementioned ideal situation of complete absorption of impact electromagnetic radiation within the absorbing volume can be achieved more easily.

[0026] Furthermore, the detector according to the present invention can be improved by having a portion of the absorption volume forming the edge of the absorption aperture tilted inward relative to the absorption volume. Similar to the aforementioned cone opposite the absorption aperture, the inwardly tilted edge around the absorption aperture also helps to ensure that electromagnetic radiation is reflected back to the absorption volume. Therefore, in this embodiment of the detector according to the present invention, the aforementioned ideal situation of complete absorption of impact electromagnetic radiation in the absorption volume can be achieved more easily.

[0027] Preferably, the detector according to the invention includes both a tapered block opposite to the absorption hole and an inclined edge surrounding the absorption hole.

[0028] Another embodiment of the detector according to the invention is characterized in that the detector includes an aperture having an aperture opening, wherein the aperture is arranged at the upper end relative to the sensing element along the assumed and / or determined impact direction of the electromagnetic radiation to be measured. Such an aperture helps to define 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, each aligned and stacked at the upper end along the assumed and / or determined impact direction. Preferably, the size and arrangement of the apertures make the source surface illuminated by the electromagnetic radiation source visible, for example from the angle of the detector, and thus electromagnetic radiation reflected from the source surface can reach the detector. Furthermore, electromagnetic radiation from other locations within the vacuum chamber is blocked by the aperture, thus improving the overall accuracy of the measurement by the detector according to the invention.

[0029] In a further improved embodiment of the detector according to the present invention, the size of the aperture opening is adapted to the absorber, particularly to the absorber aperture, such that electromagnetic radiation incident through the aperture opening strikes the absorbing surface, especially through the absorber aperture of the absorber. In this embodiment, the aforementioned limitation on the detector's field of view is further improved. Since the aperture opening and the absorber, particularly the absorber aperture, are configured to be mutually adapted, this ensures that the detector records all electromagnetic radiation passing through the aperture opening. This avoids or at least minimizes information loss.

[0030] To further restrict and optimize the field of view, multiple consecutive apertures can be used. This is particularly useful when strong sources that are close to each other need to be measured at a great distance from the source.

[0031] Furthermore, the detector according to the present invention can be improved by including 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, together with the aperture, forms a volume in front of the detector, allowing only electromagnetic radiation passing through the aperture opening to enter. Scattered electromagnetic radiation that completely misses the aperture but still impacts the absorber is blocked by the shielding element. The field of view of the detector can thus be defined with improved accuracy.

[0032] Furthermore, in another improved embodiment of the detector according to the invention, the shielding element extends further along the absorber along the assumed impact direction of the electromagnetic radiation. Nevertheless, electromagnetic radiation impacting the absorber away from the absorption surface can deposit energy into the absorber, thereby distorting the detector's measurement results. The shielding element, extending further along the absorber, covers the absorber and intercepts all incident electromagnetic radiation. Therefore, measurement distortion of the detector can be avoided or at least minimized.

[0033] In another preferred embodiment, the detector according to the invention is characterized in that the detector comprises two or more sensing elements, whereby the two or more sensing elements are adjacent to each other and thermally decoupled. As mentioned above, during the evaporation process, the source surface can change its spatial shape, in particular, the source surface can form a convex or concave shape. This spatial shape of the source surface also affects the measurement results of the detector, because some of the reflected electromagnetic radiation simply misses the main detector and / or other parts or even focuses in the direction of the detector. By providing a detector with two or more sensing elements, a more accurate distribution measurement of reflected electromagnetic radiation can be obtained. Specifically, even changes in the spatial shape and / or form of the source surface can be detected, because these changes result in detectable differences in the distribution of reflected electromagnetic radiation measured by the two or more sensing elements. By providing two or more thermally decoupled sensing elements, independent measurements can be provided for each sensing element. The adjacent arrangement of the sensing elements ensures that the gaps between the sensing elements that miss the detector are minimized.

[0034] Furthermore, the detector according to the invention can be improved by arranging two or more sensor elements in a rotationally symmetric pattern, either in rows or in a matrix, in a plane perpendicular to or at least substantially perpendicular to the assumed and / or determined impact direction of the impact electromagnetic radiation to be measured. Different patterns allow the detector to be adapted to different measurement purposes. For example, a rotationally symmetric pattern allows for the identification of focusing problems of electromagnetic radiation provided by an electromagnetic radiation source, and thus a row arrangement is particularly useful for seeing the misalignment between the electromagnetic radiation and the source surface. A matrix, especially when using a plurality of sensor elements, allows for even more detailed measurement of the distribution of electromagnetic radiation reflected from the source surface.

[0035] A further improved embodiment of the detector according to the present invention may include: in a plane perpendicular or at least substantially perpendicular to the assumed and / or determined impact direction of the electromagnetic radiation to be measured, two or more sensing elements comprising one of the following shapes:

[0035] - Rectangle

[0035] - Square

[0035] - Circle

[0035] - Circular ring

[0035] - Circular ring segment.

[0036] This list is not complete and can be further expanded to accommodate suitable shapes. In particular, for arrangement patterns with two or more of the above-mentioned sensor elements, the shape of the selected individual sensor elements for the current pattern can allow for a compact and continuous arrangement of the individual sensor elements, resulting in no unavoidable gaps between the separated sensor elements.

[0037] Furthermore, the detector according to the invention is characterized in that it includes a setting element for arranging the absorber in the vacuum lead. This particularly preferred embodiment of the detector according to the invention allows the detector to be directly arranged in and / or at the vacuum lead of the vacuum chamber. All connections, such as the inlet and outlet of the coolant channel and the electrical connections of the sensor element, can be made from outside the vacuum chamber. Within the vacuum chamber, essentially only the absorber is placed, and if present, aperture and / or shielding elements may also be present. These elements can be provided in embodiments capable of using ultra-high vacuum. Therefore, mutual damage between the components of the detector and the reaction environment within the vacuum chamber can be avoided.

[0038] In a further improved embodiment of the detector according to the present invention, the setting element includes a positioning element for changing the position of the absorber relative to the vacuum lead. Modifying the position of the absorber within the vacuum chamber can be used, for example, to replace the source material and / or the target material. This avoids interference from the detector, especially the absorber, with this replacement process. Specifically, after completing this procedure, the absorber can be rearranged near the source element to improve the measurement capability of the detector of the present invention by expanding the coverage solid angle.

[0039] According to a second aspect of the present invention, the object of the present invention is achieved by a method for controlling the flux distribution of the evaporation source material in a system for thermal evaporation using electromagnetic radiation, wherein the system includes an electromagnetic radiation source responsible for providing electromagnetic radiation, a vacuum chamber containing a reaction environment according to a first aspect of the present invention, and a detector for measuring electromagnetic radiation, wherein the source material and the target material to be vaporized are placed in the vacuum chamber, and the placement of the radiation source is such that its electromagnetic radiation is at an angle, preferably 45 degrees, striking the source surface of the source material so that the thermal evaporation and / or sublimation of the source material is below the plasma threshold, and wherein the detector for measuring electromagnetic radiation is arranged such that the electromagnetic radiation reflected from the source surface can reach the position of the detector.

[0040] The method according to the present invention includes the following steps:

[0040] a) Define a desired distribution of the flux of the source material evaporating from the source surface and a bombardment distribution of electromagnetic radiation required for this desired distribution.

[0040] b) Based on the expected distribution and impact distribution in step (a), determine the expected distribution of electromagnetic radiation reflected from the source surface.

[0040] c) Provide electromagnetic radiation with the desired impact distribution defined in step (a) by means of an electromagnetic radiation source.

[0040] d) Use a detector to measure the electromagnetic radiation reflected from the source surface.

[0040] e) Based on the measurement data in step (d), determine a measurement distribution of electromagnetic radiation reflected from the source surface.

[0040] f) Determine the difference between the expected distribution determined in step (b) and the measurement distribution determined in step (e).

[0040] g) Re-determine the impact distribution required for the electromagnetic radiation provided by the electromagnetic radiation source to minimize the difference determined in step (f), and

[0040] h) The electromagnetic radiation source provides electromagnetic radiation with the required impact distribution re-determined in step (g).

[0041] The invention according to the present invention can be used in systems that use electromagnetic radiation as a thermal evaporation source material, and can also be used by such systems. In the following text, the term "evaporation" also includes any sublimation process, even if not explicitly stated. The evaporated material can, preferably, be used to deposit a target material, for example, in the form of a thin film. Both the source material and the target material are placed in a vacuum chamber within the system, wherein the vacuum chamber contains a reaction environment suitable for depositing the target material. For example, the reaction environment can be a vacuum, or contain the necessary reaction gases such as oxygen and / or nitrogen.

[0042] During the evaporation process, electromagnetic radiation from the electromagnetic radiation source is introduced into the vacuum chamber and impacts the source surface of the source material. The energy deposit of this electromagnetic radiation evaporates or sublimates the source material. The key point in selecting the energy deposit is to avoid reaching the plasma threshold of the source material to provide pure thermal evaporation without plasma formation. By impacting at an angle, preferably 45 degrees, the path of the electromagnetic radiation can be avoided from interfering with other structures within the vacuum chamber, such as the source and / or target holding element.

[0043] Only a portion of the electromagnetic radiation impacting the source surface is absorbed by the source material and used in the evaporation process. The remaining portion of the electromagnetic radiation is reflected by the source material. In other words, the absorbed and reflected portions are directly related to each other. Specifically, the reflected portion of the electromagnetic radiation carries information about the shape and morphology of the surface; for example, flat, concave, and convex surfaces will reflect different electromagnetic radiation impacts. Thus, the shape and morphology of the surface leave a trace on the reflected electromagnetic radiation. Therefore, the actual shape and morphology of the source surface can be deduced by detecting the electromagnetic radiation reflected from the source surface. In the method of the present invention, a detector is used for detecting the reflected electromagnetic radiation, which is appropriately placed in the path of the reflected electromagnetic radiation within the vacuum chamber.

[0044] According to the present invention, in the method according to the second aspect of the present invention, the detector described in the first aspect of the present invention is used. Therefore, all the features and advantages described in detail with respect to the detector described in the first aspect of the present invention can also be provided by the method according to the second aspect of the present invention, the implementation of which includes using the detector described in the first aspect of the present invention.

[0045] As described above, the measured reflected electromagnetic radiation allows for the deduction of the actual shape and morphology of the source surface. Therefore, the actual flux distribution of evaporation or sublimation from the source surface can also be determined. Since the desired flux distribution is known, it is possible to determine how the impending electromagnetic radiation should be formed to produce the desired flux distribution upon impacting the current source surface.

[0046] The individual steps of the method according to the present invention will be described in detail below.

[0047] In the first step (a) of the method according to the invention, a desired flux distribution of the source material evaporated from the source surface is defined. In most cases, this desired flux distribution will be a flux distribution that enables uniform deposition onto the target. Nevertheless, it is also possible to provide deposition with different, particularly spatially related, desired flux distributions on the target so that the target has a location-dependent thickness.

[0048] Furthermore, step (a) also includes defining the impact distribution of the electromagnetic radiation. This impact distribution is defined on the premise that the desired flux distribution of the evaporation source material can be provided. In addition to the desired flux distribution, the initial morphology and shape of the source surface (in most cases, flat and / or circular) can also preferably be taken into consideration when defining the impact distribution of the electromagnetic radiation.

[0049] Based on the result of step (a), the expected distribution of electromagnetic radiation reflected from the source surface is determined in the next step (b) of the method of the present invention. Specifically, the anticipated distribution and the impact distribution are used to determine the expected distribution. Similar to step (a), the initial morphology and shape of the source surface can also be taken into consideration when determining the expected distribution of electromagnetic radiation.

[0050] In the next step (c) of the method according to the invention, electromagnetic radiation with the desired impact distribution defined in step (a) is provided by an electromagnetic radiation source. This electromagnetic radiation source may be directly attached to the vacuum chamber. Alternatively, the electromagnetic radiation source may be placed separately from the vacuum chamber, or even in a different room or building, and connected via a suitable guiding element, such as an optical fiber. As a result, the electromagnetic radiation impacts the source surface of the source material with the desired impact distribution, causing the thermal evaporation or sublimation of the source material below the plasma threshold.

[0051] At the same time, electromagnetic radiation that is not absorbed by the source material is reflected on the source surface. In the next step (d) of the method according to the invention, this reflected electromagnetic radiation is measured by a detector in the system. For this purpose, the detector is suitably placed in a vacuum chamber.

[0052] In the next step (e), the measurement data of step (d) in the method according to the present invention are analyzed. Specifically, the measurement of electromagnetic radiation distribution is determined based on the measurement results of step (d).

[0053] The measurement distribution information 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 measurement distribution determined in step (e). In other words, regardless of whether the expected distribution matches the actual measurement distribution, information will be generated after the execution of step (f). The greater the error between the two distributions, the greater the error between the actual flux distribution of the evaporation source material and the expected distribution defined in step (a) of the method according to the present invention.

[0054] Based on the findings in step (f), the required impact distribution is re-determined in step (g) of the subsequent method according to the invention. Specifically, the difference between the measured distribution and the expected distribution allows for information about the actual shape and morphology of the source material. Therefore, based on this improved determination of the required impact distribution of electromagnetic radiation, it is possible to achieve the desired flux distribution of the evaporation source material. Thus, the difference determined in step (f) should be automatically minimized.

[0055] In the final step (h) of the method according to the present invention, electromagnetic radiation with the desired impact distribution redefined in step (g) is provided by the electromagnetic radiation source. As a result, the electromagnetic radiation with the redefined desired impact distribution impacts the source surface of the source material, causing the thermal evaporation or sublimation of the source material below the plasma threshold. Since the actual shape and morphology of the source surface are taken into account, the match between the expected distribution of the flux of the evaporating source material and the current actual distribution is improved.

[0056] In summary, the method according to the present invention allows for the active adjustment of the flux distribution of the source material during evaporation or sublimation based on actual measurements during the operation of individual evaporation systems. Therefore, controlling the flux distribution is feasible. Consequently, the evaporation deposition of the target material can also be improved.

[0057] Furthermore, the method according to the invention may include a anticipated distribution defined in step (a) that includes a time dependence. The time dependence of the invention may, for example, be applied to a spatial shape and / or the orientation of the anticipated distribution. Alternatively or additionally, the intensity of the anticipated distribution may vary over time. As a result, the vapor deposition of the target material can be controlled in a specific manner, including, for example, variations in the spatial thickness of the vapor deposition of the target material. Preferably, since the anticipated distribution is time-dependent, the remaining steps in the method according to the invention are adjusted accordingly, i.e., for example, the required distribution and the anticipated distribution include an adjusted time dependence, and the respective measurements, comparisons, and re-determinations in steps (d), (f), and (g) are repeated following this time dependence.

[0058] Furthermore, the method according to the present invention is 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. The characteristics of step (b) of the method according to the present invention are numerous; specifically, different methods for determining the expected distribution can be applied, if feasible and technically significant. The calculation of the expected distribution is based on all accessible information, such as the anticipated distribution and the desired distribution. Empirical estimation is based on general assumptions, such as the assumed form or shape of the source material. A combination of calculation and estimation is preferred. Experimentally measuring the expected distribution provides a very accurate expected distribution. The disadvantage of this method is the additional time and effort required for experimental measurements.

[0059] The method according to the invention may preferably include repeating steps (d) to (h). The repetition rate may be robust, for example, continuously repeating steps (d) to (h) at a frequency of 10 Hz or even higher. The repetition rate may also be adjusted, thereby allowing manual triggering of corresponding repetitions and / or if parameters exceed or fall below a certain threshold, for example, a detector detects energy deposition from electromagnetic radiation reflected from the source surface. The repetition of steps (d) to (h) ensures that the extended time provides the possibility of a desired distribution. Specifically, the repetition allows for a closed-loop controlled supply flux of the evaporating or sublimating source material with a desired distribution.

[0060] Furthermore, the method according to the invention may include electromagnetic radiation light, particularly laser light in the range of 100 nm to 1400 nm. The light, particularly laser light, can be readily provided and supplied to the vacuum chamber from a source located remotely from the vacuum chamber. Specifically, the light can also be provided at a wide range of energy densities, and thus electromagnetic radiation below the plasma threshold of a particular source material for evaporation can be readily provided.

[0061] According to another embodiment, the method according to the invention is characterized in that the response function of the detector is considered in steps (e) and / or (f). The response function of the detector has an immediate effect on the measurement of reflected electromagnetic radiation. For example, the solid angle covered by the detector limits the measurement signal. The dead time of the detector and, for example, the energy correlation of the detector sensitivity also affect the actual measurement. Therefore, by considering the response function of steps (e) and / or (f), the influence of the detector setup on the measurement distribution can be considered at least partially, and preferably completely.

[0062] Additionally or alternatively, the method according to the 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 mentioned above, changes in the shape and / or morphology of the source surface affect the distribution of reflected electromagnetic radiation. Specifically, concave and convex portions of the source surface reflect impacted electromagnetic radiation, especially dispersed incident electromagnetic radiation, in different ways. The shape and morphology of the surface thus leave a trace on the reflected electromagnetic radiation. Therefore, by detecting the size and / or shape of the electromagnetic radiation reflected from the source surface, the shape and / or morphology information deeply imprinted on the reflected electromagnetic radiation by the source material can be detected particularly easily.

[0063] Furthermore, the method according to the invention is characterized in that the electromagnetic radiation source comprises two or more emitter sections, whereby in steps (c) and (h), each emitter section provides electromagnetic radiation impacting the source surface, and wherein the system respectively includes two or more detectors, each detector being arranged accordingly to measure the electromagnetic radiation provided by one of the emitters and reflected from the source surface. In other words, according to this embodiment, the source surface is illuminated by two separate beams, whereby each beam is monitored by a separate dedicated detector. Each pair of emitter sections and designated detectors can be implemented as both emitting and measuring elements according to the method of the invention. In summary, a more uniform distribution of electromagnetic radiation impacting the source surface can be provided, and active control of such a distribution as described above for an electromagnetic radiation source with a single emitter can also be provided hereinafter. This also improves the flatness of the desired distribution that can be provided.

[0064] Furthermore, the method of the present invention may include: for each of two or more additional detectors, using the detector for measuring electromagnetic radiation as described in the first aspect of the present invention. Therefore, all the features and advantages described in detail with respect to the detector according to the first aspect of the present invention may also be provided by the method according to the second aspect of the present invention, in which the detector according to the first aspect of the present invention is used as two or more additional detectors.

[0065] Furthermore, the method according to the present invention can be improved by having individual electromagnetic radiations provided by two or more transmitter portions impact the source surface in a radially symmetrical manner. In other words, the transmitter portions are evenly distributed on the source surface. As a result, if the impact distribution of the two or more transmitter portions is equal, it indicates that the combination of impact distributions is rotationally symmetrical. Specifically, this can prevent effects such as the molten source material being leached and / or tilted in the direction of the impact electromagnetic radiation.

[0066] A further embodiment of the method according to the invention is characterized in that two or more emitter sections provide electromagnetic radiation with adjustable power density and / or shape and / or size. As described above, in some cases, providing the desired distribution, including spatial distribution on the source surface, can be advantageous. This can be easily provided by two or more emitter sections, whereby each emitter section can radiate electromagnetic radiation whose individual power density, shape, and / or size can be modified separately. In summary, this allows the flux of source material evaporating from the source surface to be distributed in a manner that depends on its position on the source surface.

[0067] According to a third aspect of the present invention, the object of the present invention is achieved by an electromagnetic radiation thermal evaporation system, the system comprising an electromagnetic radiation source providing electromagnetic radiation, a vacuum chamber containing a reaction environment and a main detector for measuring electromagnetic radiation; wherein a source material and a target material to be vaporized are arranged in the vacuum chamber and the electromagnetic radiation source is arranged such that its electromagnetic radiation strikes the source surface of the source material at an angle preferably 45 degrees, so that the thermal evaporation and / or sublimation of the source material is below the plasma threshold, wherein the main detector for measuring electromagnetic radiation is arranged such that the electromagnetic radiation reflected from the source surface can reach the main detector; wherein the system according to the third aspect of the present invention is suitable for carrying out the method according to the second aspect of the present invention. Therefore, all the features and advantages described in detail in the method according to the second aspect of the present invention can also be provided by the system of the third aspect of the present invention, which is suitable for carrying out the method according to the second aspect.

[0068] According to the present invention, the system according to the present invention is characterized in that the detector of the system is constructed by means of the first state sample of the present invention. Therefore, all the features and advantages described in detail with respect to the detector of the first state sample of the present invention can also be provided by the system of the third state sample of the present invention, which includes at least one detector according to the first state sample of the present invention. In other words, during the execution of the method according to the second state sample of the present invention, at least the main detectors (preferably each detector for electromagnetic radiation) are constructed as detectors according to the first state sample of the present invention. [Simplified Explanation of the Diagram]

[0069] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings:

[0069] Figure 1 shows the system according to the present invention.

[0069] Figure 2 shows a first feasible embodiment of the detector according to the present invention.

[0069] Figure 3 shows an absorber with an absorption volume.

[0069] Figure 4 shows an embodiment of the detector according to the present invention, having two sensing elements.

[0069] Figure 5 shows the arrangement of the sensor elements.

[0069] Figure 6 shows the flux of the source material evaporating from the flat source surface.

[0069] Figure 7 shows the flux of the source material evaporating from the concave source surface.

[0069] Figure 8 shows the flux of the source material evaporating from the surface of the convex source.

[0069] Figure 9 shows the tilt of a drop of molten source material.

[0069] Figure 10 shows the electromagnetic radiation emitted by the molten droplet through two impacts.

[0069] Figure 11 shows the possible arrangements of the three radiation emitters.

[0069] Figure 12 shows the target being scanned by adjusting two impact electromagnetic radiation beams.

Implementation Method

[0070] Figure 1 shows the main components of a system 10 according to the invention, which uses electromagnetic radiation 120 to thermally evaporate the source material 20. The source material 20 is arranged inside a vacuum chamber 12, thereby limiting the range of the reaction environment 16. The vacuum chamber 12 itself is only shown next to the vacuum lead 14. An electromagnetic radiation source 110 is provided at one location on the vacuum lead 14, and a detector 40 according to the invention is provided at the other location.

[0071] During operation of system 10, electromagnetic radiation source 110 provides electromagnetic radiation 120 that is directed and impacts the source surface 22 of source material 20. Source material 20 absorbs a portion of the electromagnetic radiation 120, thus some of the source material 20 evaporates or sublimates, as shown by the circular dashed line in Figure 1. Target material 18 is arranged relative to source material 20. The evaporated source material 20 reaches target material 18 and forms a vapor deposition on the surface of target material 18.

[0072] The remaining portion of the electromagnetic radiation 120 is reflected from the source surface 22. Since the radiation direction of the electromagnetic radiation source 110 and the position and approximate orientation of the source surface 22 are known, the detector 40 can be positioned on the assumed and / or determined impact direction 122 of the reflected electromagnetic radiation 120. As described for the electromagnetic radiation source 110, the detector (especially its absorber 52) can also be positioned at the vacuum lead 14 of the vacuum chamber 12.

[0073] The detector 40 according to the invention functions as a thermal radiometer. Electromagnetic radiation 120 strikes the absorbing surface 60 of the absorber 52 and is at least partially absorbed. As depicted, the absorbing surface 60 faces the source surface 22 and is therefore also deposited with the evaporated source material 20, as shown in FIG1. ​​Thus, after a short settling time, the absorbing surface 60, like the source surface 22, has the same or at least similar absorption and reflection properties.

[0074] The aforementioned energy deposition within the absorber 52 results in a temperature change in the absorber 52 or at least an increase in cooling requirements. By measuring the temperature or its change, the evaporation rate and / or flux distribution of the source material 20 that evaporates or sublimates by impact electromagnetic radiation 120 can be determined.

[0075] FIG2 depicts a cross-section of a possible embodiment of the detector 40 according to the present invention. The detector 40 includes a single sensor element 50 having an absorber 52, which is preferably composed of a metal with high thermal conductivity, such as copper or aluminum. A setting element 42 allows the absorber 52 to be aligned at the vacuum lead 14 of the vacuum chamber 12 of the system 10 according to the present invention. Specifically, the setting element 42 includes a positioning element 44 to modify the actual position of the absorber 52 within the reaction environment 16 of the vacuum chamber 12. As shown in FIG1, modifications to other elements in the system 10 arranged in the vacuum chamber 12, for example, can thus provide source material 20 without any obstruction from the detector 40.

[0076] The detector 40 according to the present invention is based on the principle of a thermal radiometer. Electromagnetic radiation 120 strikes the absorbing 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.

[0077] To this end, in the detector 40 depicted according to the invention, two different measurement methods and separate thermal sensing elements 70 are implemented. Temperature or its changes can be measured using separate methods. However, higher accuracy can be provided by combining the two methods described below.

[0078] In the first method, the temperature sensor 74, preferably a thermocouple element 76, is arranged within the inner hole 54 of the absorber 52, particularly near the absorbing surface 60. As described above, the energy deposited by the electromagnetic radiation 120 striking the absorbing surface 60 causes the temperature of the absorber 52 to rise. The thermocouple 76 located within the absorber 52 near the absorbing surface 60 can measure this temperature rise in terms of absolute temperature or temperature change. Therefore, this measurement method also allows for accurate determination of the amount of energy deposited in the absorber 52.

[0079] In the second method, the absorber 52 includes a cooling system 80 for active cooling. Coolant 84 flows through the absorber 52 via cooling conduit 82, thereby absorbing energy deposited in the absorber 52 due to impact electromagnetic radiation 120. As depicted in FIG2, a flow sensor 72 and a temperature sensor 74 measure the flow rate and temperature of the coolant 84 at the inlet and outlet of the cooling conduit 82, respectively. In summary, the combination of these measurements allows for accurate determination of the amount of energy deposited in the absorber 52.

[0080] FIG3 shows a cross-section of a rotationally symmetric preferred embodiment of the detector 40 according to the present invention, particularly a cross-section of its absorbing surface 60. The absorber 52 of the sensor element 50 depicted according to this embodiment includes a hollow absorbing volume 56 at its end facing the impact direction 122 of the electromagnetic radiation 120 to be measured. This absorbing volume 56 includes a single opening, namely an absorption aperture 62, which allows the impact electromagnetic radiation 120 to enter the absorbing volume 56. The inner sidewall 58 of the absorbing volume 56 forms the absorbing surface 60. In other words, the electromagnetic radiation 120 enters the absorbing volume 56 and is reflected multiple times within the absorbing volume 56; as indicated by the arrows in FIG3, thus each time the impact electromagnetic radiation 120 is reflected, a portion of its energy is absorbed. Ideally, the electromagnetic radiation 120 is trapped in the absorbing volume 56 and thus completely absorbed by the absorbing surface 60. To improve the possibility of this ideal situation, the sidewall portion forming the edge 64 surrounding the absorption aperture 62 is inclined inward relative to the absorbing volume 56. This inwardly sloping surface provides the additional advantage of preventing electromagnetic radiation from impacting these surfaces from being reflected back in the direction of impact. Furthermore, the portion of the absorbing surface 60 opposite the absorbing hole 62 is conical with its tip pointing towards the absorbing hole 62.

[0081] Figure 4 shows a detector 40 having two sensing elements 50. The sensing elements 50 are arranged adjacent to each other and are thermally decoupled. Each sensing element 50 includes its own absorber 52 and absorbent surface 60. The remainder of the sensing elements 50 is not shown. In summary, providing two or more sensing elements 50 can provide more detailed information about the absorbed electromagnetic radiation 120, such as for determining the evaporation rate and / or the flux distribution of the evaporation source material 20 (not shown).

[0082] Furthermore, two stacked and aligned apertures 90 are arranged at the top of each of the sensor elements 50. The aperture openings 92 limit the solid angle received by each individual sensor element 50. Crosstalk between the sensor elements 50, indicated by the dashed arrow, can be avoided. Furthermore, shielding elements 94 are arranged between the apertures 90 and, even further along, each individual absorber 52. On the one hand, these shielding elements 94 further reduce the aforementioned crosstalk. On the other hand, electromagnetic radiation 120 striking the side surface of the absorber 52 is also blocked and will not distort the measurement results.

[0083] As mentioned in FIG. 4, the detector 40 according to the present invention may include two or more sensor elements 50. Some examples of the shape and arrangement of the sensor elements 50 and their absorption surfaces 60 are shown in FIG. 5. Obviously, a high-resolution pixel array similar to that of an electronic camera is possible to a certain extent. In summary, the most suitable measurement purpose of the detector 40 can be selected from different arrangement patterns, such as determining the evaporation rate and / or the flux distribution of the evaporation source material 20.

[0084] The upper left area of ​​Figure 5 shows a standard geometric figure with a simple circular active area.

[0085] The movement of the impact direction 122 of the electromagnetic radiation 120 can be detected in four quadrants, as shown in the upper right area. Here, the sensor elements 50 are square in shape and arranged such that movement mainly along their diagonals in the horizontal and vertical directions can be detected, while maintaining a small number of sensor elements 50.

[0086] The lower left area of ​​Figure 5 shows a third arrangement of the sensor elements 50 forming a ring with rotational symmetry. This pattern is most sensitive to the focusing or defocusing of the electromagnetic radiation 120 provided by the electromagnetic radiation source 110.

[0087] As shown in the lower right region of Figure 5, although in this case only in the vertical direction, position and defocus can be detected by means of the striped rectangular sensor element 50. This may be advantageous because the electromagnetic radiation 120 is reflected at an angle of approximately 45° on the impact direction 122 at the source surface 22, and is more strongly affected in the plane containing the incident and reflected beams than perpendicular to that plane.

[0088] The following three figures, Figures 6, 7, and 8, show how the shape and morphology of the source material, or the source surface 22, affects the flux distribution 30 of the evaporated source material 20 and the electromagnetic radiation 120 reflected from the source surface 22 into the measurement distribution 134 on the detector 40. Figures 6, 7, and 8 will be described together below, thereby highlighting the differences between the figures. Furthermore, the method according to the present invention will be described.

[0089] The electromagnetic radiation source 110 provides electromagnetic radiation 120 having an impact distribution 130. This provision of electromagnetic radiation 120 is accomplished in step (c) of the method according to the invention. According to step (a), the impact distribution 130 is defined such that the flux distribution 30 of the source material 20 evaporating from the source surface 22 also corresponds to the desired distribution 32 of the evaporating and / or sublimating source material 20 defined in step (a). This condition can be easily satisfied, particularly in the case shown in FIG. 6, which has a flat source surface 22. The target material 18 arranged in the reaction environment 16 relative to the source material 20 can be deposited as expected with the evaporating source material 20.

[0090] To allow control of the vapor deposition process, the detector 40 is arranged to measure the electromagnetic radiation 120 reflected from the source surface 22 in the impact direction 122, particularly in step (d) of the method according to the invention. As a result, 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 changes in the morphology and / or shape of the source surface 22 will leave their traces on the reflected electromagnetic radiation 120, this measurement distribution 134 can be used to detect any deviations from the assumed ideal situation.

[0091] To this end, in the second step (b) of the method according to the invention, the expected distribution 132 of the reflected electromagnetic radiation 120 is determined, for example, by calculation, empirical estimation, or experimental determination. The difference between the two distributions 132, 134 can be determined by comparing the measured distribution 134 of the electromagnetic radiation 120 reflected from the source surface 22 with the expected distribution 132 in step (f) of the method according to the invention.

[0092] Based on the discrepancies discovered in step (f) of the method according to the invention, step (g) includes redetermining the impact distribution 130 to eliminate the discrepancies. Finally, in the final step (h), the electromagnetic radiation source 110 provides electromagnetic radiation 120, for example, electromagnetic radiation with a wavelength between 100 nm and 1400 nm, having the new redetermined impact distribution 130. This allows for practical control of the flux distribution 30 of the evaporating source material 20.

[0093] Specifically, at least steps (d) to (h) of the method according to the invention can be repeated to provide active closed-loop control of evaporation. Alternatively or additionally, in step (a), the anticipated distribution 32 can already be defined as having a time dependence.

[0094] As described above, Figure 6 shows a source material 20 with a flat source surface 22. This is an ideal case and can be easily calculated. The actual flux distribution 30 is equal to the expected distribution 32.

[0095] After irradiation with electromagnetic radiation 120, a concave portion may form on the source surface 22, for example, due to the actual evaporation of the source material 20. Consequently, the flux distribution 30 and reflection of the electromagnetic radiation change. The flux distribution 30 is no longer equal to the expected distribution 32 (not shown). By comparing the new measured distribution 134 with the expected distribution 132, this situation can be identified and resolved by accordingly re-determining the impact distribution 130.

[0096] Figure 8 shows a situation similar to that of Figure 7. The only difference is the shape of the source surface 22, which is convex rather than concave. All descriptions of the solutions presented for distributions 30, 130, 132, 143 and above are the same as those for Figure 7, and are therefore mentioned here.

[0097] Figure 9 shows some specific characteristics of the source material 20. The depicted source material 20 is provided as a self-supporting rod, with the source surface 22 arranged at the top of the rod. By irradiating the source surface 22 with impact electromagnetic radiation 120, a droplet of molten source material 20 forms on the top of the rod composed of source material 20. When the electromagnetic radiation 120 impacts at an angle, for example 45°, the side of the rod closer to the electromagnetic radiation 120 absorbs more energy. Therefore, as a result, the molten droplet of source material 20 is skewed and / or tilted toward the direction of the electromagnetic radiation 120. Specifically, the flux distribution 30 also follows this spatial orientation.

[0098] Figure 10 illustrates a possible 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 flux distribution 30 is then no longer distorted and is once again equal to the desired distribution 32.

[0099] The number of beams of electromagnetic radiation 120 is not limited to two. Figure 11 illustrates an embodiment of the system 10 according to the invention, which has an electromagnetic radiation source 110 comprising three emitter portions 112. The emitter portions 112 are arranged rotationally symmetrically about a source surface 22 on a source material 20. For each beam of electromagnetic radiation 120, a dedicated detector 40 is provided. Therefore, the method described above according to the invention can be implemented individually and in combination with each pair of emitter portions 112 and detectors 40. Specifically, the emitter portions 112 can provide electromagnetic radiation 120 with adjustable power density and / or shape and / or size. Therefore, the actual impact distribution 130, as well as the flux distribution 30 and the anticipated distribution 32, can also provide spatial variations even on the source surface 22.

[0100] This situation is depicted in Figure 12. As shown by the arrows of different lengths, the impact distributions 130 of the two impacting electromagnetic radiation 120 beams are inconsistent. This difference, for example, is provided by the different power densities of the provided electromagnetic radiation 120 beams, resulting in a slight distortion in the flux distribution 30 of the source material 20 evaporating from the source surface 22. In this case, this is intentional and the flux distribution 30 is equal to the intended distribution 32. Obviously, the target material 18 cannot be uniformly deposited with this flux distribution 30 because the flux distribution 30 is directed to one side of the target material 18. By changing the individual impact distributions 130 of the electromagnetic radiation 120 beams, the direction of the flux distribution 30 can be changed. As a result, the intended deposition thickness or thickness variation, or the time-dependent scanning of the intended distribution 32 on the target material, can be achieved and tracked by the actual flux distribution 30.

Claims

1. A detector (40) for measuring electromagnetic radiation (120) reflected onto a source surface (22), comprising a sensor element (50) having an absorber (52) including an absorbing surface (60) for absorbing at least a portion of the electromagnetic radiation (120), wherein, The sensing element (50) further includes a thermal element (70) for measuring the temperature of the absorber (52) to detect the absolute temperature and / or temperature change caused by the electromagnetic radiation (120) absorbed by the absorber (52), wherein the thermal element (70) includes a temperature sensor (74) disposed in an inner hole (54) in the absorber (52), wherein the inner hole (54) terminates in the absorber (52), wherein the absorber (52) includes a cooling system (80) for actively cooling the absorber (52), wherein the cooling system (80) includes at least one cooling conduit within the absorber (52) through which a fluid of coolant (84) passes through the absorber (52).

2. The detector (40) as described in claim 1, wherein, The absorbing surface (60) absorbs light with wavelengths between 100 nm and 1400 nm.

3. The detector (40) as described in claim 1, wherein, The heat-sensing element (70) includes a flow sensor (72) for measuring the fluid of the coolant (84) passing through the cooling pipe of the absorber (52) and a temperature sensor (74) for measuring the absolute temperature of the coolant (84) and / or the temperature change of the coolant (84) caused by the flow through the cooling pipe in the absorber (52).

4. The detector (40) as described in claim 1 or claim 2, wherein, The absorber (52) comprises a metal.

5. The detector (40) as described in claim 1 or claim 2, wherein, The absorber (52) surrounds one end of a hollow absorption volume (56), whereby the inner wall (58) of the absorption volume (56) forms an absorption surface (60), and wherein the absorption volume (56) includes an absorption hole (62), whereby the absorption hole (62) is aligned with the assumed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured.

6. The detector (40) as described in claim 5, wherein, The absorption surface (60) is partially formed into a cone shape within the absorption volume (56), with the cone of the absorption surface (60) facing the absorption hole (62).

7. The detector (40) as described in claim 6, wherein, The portion of the absorption volume (56) of the edge (64) forming the absorption hole (62) is inclined inward relative to the absorption volume (56).

8. The detector (40) as described in claim 1 or claim 2, wherein, The detector (40) includes an aperture (90) having an aperture opening (92), wherein the aperture (90) is arranged at the upper end relative to the sensor element (50) along an assumed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured.

9. The detector (40) as described in claim 8, wherein, The size of the aperture opening (92) is suitable for the absorber (52) so that the electromagnetic radiation (120) is incident through the aperture opening (92) and impacts the absorbing surface (60) of the absorber (52).

10. The detector (40) as described in claim 8, wherein, The detector (40) includes a shielding element (94) that extends between the aperture (90) and the absorber (52) along the assumed and / or determined impact direction (122) of the electromagnetic radiation (120) to be measured.

11. The detector (40) as described in claim 10, wherein, The shielding element (94) extends further along the absorber (52) along the assumed impact direction (122) of the electromagnetic radiation (120).

12. The detector (40) as described in claim 1 or claim 2, wherein, The detector (40) includes two or more sensing elements (50) such that the two or more sensing elements (50) are adjacent to each other and thermally decoupled.

13. The detector (40) as described in claim 12, wherein, The two or more sensor elements (50) 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 (122) of the impact electromagnetic radiation (120) to be measured.

14. The detector (40) as described in claim 12, wherein, In a plane perpendicular 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: - rectangle - square - circle - circular ring - circular ring segment.

15. The detector (40) as described in claim 1 or claim 2, wherein, The detector (40) includes a setting element (42) for arranging the absorber (52) on the vacuum lead (14).

16. The detector (40) as described in claim 15, wherein, The setting element (42) includes a positioning element that modifies the position of the absorber (52) relative to the vacuum lead (14).

17. A method for controlling the flux distribution (30) of an evaporation source material (20) in a system (10) of thermal evaporation using electromagnetic radiation (120), wherein, The system (10) includes an electromagnetic radiation source (110) providing electromagnetic radiation (120), a vacuum chamber (12) containing a reaction environment (16), and a detector (40) as described in claim 1 for measuring the electromagnetic radiation (120), wherein the source material (20) to be coated and the target material (18) are arranged in the vacuum chamber (12) and the radiation source is arranged such that its electromagnetic radiation (120) impacts the source surface (22) of the source material (20) at an angle, so that the thermal evaporation and / or sublimation of the source material (20) is achieved. 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) can reach the position of the detector (40); the method includes the following steps: a) defining a desired distribution (32) of the flux of the source material (20) evaporating from the source surface (22) and the impact distribution (130) of the electromagnetic radiation (120) required for the desired distribution (32), b) based on the desired distribution (32) and the impact in step (a). c) Determine the expected distribution (132) of the electromagnetic radiation (120) reflected on the source surface (22) by the electromagnetic radiation source (110), d) Provide the electromagnetic radiation (120) with the desired impact distribution (130) defined in step (a) from the electromagnetic radiation source (110), e) Measure the electromagnetic radiation (120) reflected on the source surface (22) by the detector (40), and f) Based on the measurement data in step (d), determine the measurement of the electromagnetic radiation (120) reflected on the source surface (22). f) determine the difference between the expected distribution (132) determined in step (b) and the measured distribution (134) determined in step (e), g) redetermine the impact distribution (130) required for the electromagnetic radiation (120) provided by the electromagnetic radiation source (110) to minimize the difference determined in step (f), and h) provide the electromagnetic radiation (120) with the required impact distribution (130) redetermined in step (g) by the electromagnetic radiation source (110).

18. The method as described in claim 17, wherein, The anticipated distribution (32) defined in step (a) includes time correlation.

19. The method as described in claim 17 or claim 18, 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).

20. The method as described in claim 17 or claim 18, wherein, This involves repeating step (d) through step (h).

21. The method as described in claim 17 or claim 18, wherein, Light with wavelengths between 100 nm and 1400 nm is used as the electromagnetic radiation (120).

22. The method as described in claim 17 or claim 18, wherein, In step (e) and / or step (f), the response function of the detector (40) is taken into consideration.

23. The method as described in claim 17 or claim 18, wherein, In step (f), the size and / or shape of the expected distribution (132) and the measured distribution (134) are used to determine the difference.

24. The method as described in claim 17 or claim 18, wherein, The electromagnetic radiation source (110) includes two or more transmitter sections (112), whereby each transmitter section (112) in steps (c) and (h) provides electromagnetic radiation (120) that impacts the source surface (22), and wherein the system (10) includes each of the two or more detectors (40), each detector (40) being arranged accordingly to measure the electromagnetic radiation (120) provided by one of the transmitter sections (112) and reflected from the source surface (22).

25. The method as described in claim 24, wherein, For each of the two or more additional detectors (40), the detector (40) for measuring electromagnetic radiation (120) according to request item 1 is used.

26. The method as described in claim 24, wherein, The individual electromagnetic radiation (120) provided by the two or more transmitter sections (112) strikes the source surface (22) radially and symmetrically.

27. The method as described in claim 24, wherein, The two or more transmitter sections (112) provide the electromagnetic radiation (120) having adjustable power density and / or shape and / or size.

28. A system (10) for thermal evaporation using electromagnetic radiation (120), comprising an electromagnetic radiation source (110) providing the electromagnetic radiation (120), a vacuum chamber (12) containing a reaction environment (16), and a detector (40) for measuring the electromagnetic radiation (120), wherein, The source material (20) and target material (18) to be vaporized are arranged in the vacuum chamber (12) and the radiation source is arranged such that the electromagnetic radiation (120) is at an angle to strike the source surface (22) of the source material (20) so that the thermal evaporation and / or sublimation of the source material (20) is below the plasma threshold. The detector (40) for measuring the electromagnetic radiation (120) is located at the position where the electromagnetic radiation (120) reflected from the source surface (22) can reach the detector (40). The detector (40) is constructed according to claim 1. The system (10) is suitable for performing the method as claimed in claim 17.

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