Operating method of a laser system, laser system, and evaporation system

Abstract

The present invention relates to an operating method of a laser system (10) that provides a laser beam (20) capable of heating and / or evaporating and / or sublimating a target (120) disposed within a reaction chamber (110) of an evaporation system (100). The laser system (10) includes a laser light source (12) for providing the laser beam (20) and beam adjustment means (40) for adjusting at least a cross-section (22) of the laser beam (20). The beam adjustment means (40) includes, along the laser beam (20), a first adjustment unit (42), a clipping aperture (70) having a clipping opening (72), and a second adjustment unit (44). Further, the present invention relates to a laser system (10) for heating and / or evaporating and / or sublimating a target (120) disposed within a reaction chamber (110) of an evaporation system (100). The laser system (10) includes a laser light source (12) for providing the laser beam (20), and the laser system (10) includes beam adjustment means (40) having, along the laser beam (20), a first adjustment unit (42), a clipping aperture (70) having a clipping opening (72), and a second adjustment unit (44). Further, the present invention relates to an evaporation system (100) for coating a substrate (126) with evaporated and / or sublimated material of a source (124), the evaporation system (100) including a reaction chamber (110) having a reaction volume (112) for disposing the source (124) and the substrate (126), a substrate laser system (10) for heating the substrate (126), and a source laser system (10) for evaporating and / or sublimating the material of the source (124).

Description

Technical Field

[0001] The present invention relates to a method for operating a laser system for providing a laser beam capable of heating and / or evaporating and / or sublimating a target disposed within a reaction chamber of an evaporation system. The laser system includes a laser light source for providing a laser beam and beam conditioning means for conditioning at least a cross-section of the laser beam. The beam conditioning means includes, along the laser beam, a first conditioning unit, a clipping aperture having a clipping opening, and a second conditioning unit. Further, the present invention relates to a laser system for heating and / or evaporating and / or sublimating a target disposed within a reaction chamber of an evaporation system. The laser system includes a laser light source for providing a laser beam, and the laser system includes beam conditioning means including, along the laser beam, a first conditioning unit, a clipping aperture having a clipping opening, and a second conditioning unit. Further, the present invention relates to an evaporation system for coating a substrate with evaporated and / or sublimated material of a source, the evaporation system including a reaction chamber having a reaction volume for disposing the source and the substrate, a substrate laser system for heating the substrate, and / or a source laser system for evaporating and / or sublimating the material of the source.

Background Art

[0002] In particular, in evaporation systems used for thermal laser epitaxy (TLE), the surface of either the substrate or the source is preferably heated by laser radiation. In the case of the source, the irradiation is usually performed at an angle with respect to the surface normal, and in the case of the substrate where the back surface of the wafer is heated, normal incidence is ideal.

[0003] In particular, in TLE, the output densities required to evaporate and / or sublime different materials can also vary extremely. For example, some source materials require 1 W, while others, when evaporated with the same laser of the same shape, exceed 500 W. In the case of substrate heating, substrates with very different sizes, such as diameters from 5 mm to 100 mm or side lengths, can be heated, and as a result, it is beneficial that the area increases by a factor of 400. Also, substrates with different materials may each require a factor exceeding 100 in laser output density (intensity per unit area) for the optimal process temperature.

[0004] Therefore, especially in TLE applications, it is desirable to be able to control the heating laser with a dynamic range of at least 1000 (if not more). However, lasers have a threshold, which means that they suddenly turn on at a certain magnitude of their maximum intensity, often about 3% or more. Therefore, it is not easy to achieve a dynamic range where the ratio between, for example, the minimum intensity and the maximum controllable intensity exceeds 30.

[0005] A known solution to this requirement is the pulsed operation of lasers that adjusts the time-averaged output by pulse width modulation. However, pulse width modulation is harmful because it generates strong time-varying signals and regularly causes excessive thermal distortion and substrate failure even at multi-kHz repetition frequencies. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0006] In view of the above, an object of the present invention is to provide an improved method for operating a laser system, an improved laser system, and an improved evaporation system that do not have the above-mentioned drawbacks of the prior art. In particular, an object of the present invention is to provide a laser system, an improved laser system, and an improved evaporation system that enable changing the output density of the laser light provided by a laser light source provided on the surface of a target, and in particular, to provide a dynamic range of 1000 or more in output density between the lowest achievable output density and the highest achievable output density. **Means for Solving the Problems**

[0007] This object is achieved by the respective independent patent claims. In particular, this object is achieved by a method of operating a laser system according to claim 1, a laser system according to claim 8, and an evaporation system according to claim 26. The dependent claims describe preferred embodiments of the present invention. The details and advantages described with respect to the method of operating a laser system according to the first aspect of the present invention are also applicable to the laser system according to the second aspect of the present invention and the evaporation system according to the third aspect of the present invention, and vice versa in terms of technical meaning.

[0008] According to a first aspect of the present invention, the object of the present invention is a laser system capable of providing a laser beam for heating and / or evaporating and / or sublimating a target disposed in a reaction chamber of an evaporation system, the laser system comprising a laser light source for providing the laser beam and beam adjusting means for adjusting at least a cross-section of the laser beam, and is achieved by a method of operating the laser system, the beam adjusting means comprising, along the laser beam, a first adjusting section, a clipping aperture having a clipping opening, and a second adjusting section.

[0009] The method of the present invention includes the following steps: a) determining a desired output of the laser beam provided on the surface of the target and a desired cross-section of the laser beam; b) setting a laser light source for providing a laser beam having an initial output and an initial cross-section; c) setting a first adjustment unit and / or a clipping aperture based on the initial output, the initial cross-section, and the desired output, and providing an intermediate output matched to the desired output for the laser beam after irradiation through the clipping aperture; d) setting a second adjustment unit for providing the laser beam with the desired output and the desired cross-section at the surface of the target; e) providing a laser beam by the laser light source set in step b), and subsequently adjusting the laser beam by the beam adjustment means set in steps c) and d) to provide the laser beam set on the surface of the target in step a) with the desired output and the desired cross-section respectively.

[0010] The method according to the invention enables the operation of a laser system, preferably an evaporation system, in particular a laser system used for TLE applications. The laser system provides a laser beam, which is also preferably used in the evaporation system in this case. The laser beam can be used to evaporate and / or sublime a target, for example the material of a source. Alternatively or additionally, the laser beam can also be used only to heat a target, for example a substrate coated with the evaporated and / or sublimed material of the source.

[0011] In addition to the laser light source, the laser system includes beam adjustment means for changing the characteristics of the laser beam, in particular for changing at least the cross-section of the laser beam. The beam adjustment means has three forcing parts, namely a first adjustment part, a clipping aperture, and a second adjustment part, respectively, particularly along the direction of the laser beam. The clipping aperture preferably includes a clipping opening at the center of the laser beam. The material of the clipping aperture is preferably opaque or at least essentially opaque to the laser beam. Thus, the clipping aperture can very effectively cut the laser beam.

[0012] The method according to the invention is intended to provide a laser beam having a wide range of possible output densities at the target. In particular, the method according to the invention can provide a laser beam having a desired output density at the target. The steps required for this task are described below.

[0013] In the first step a) of the method according to the invention, the desired output density required at the target is determined. The output density is composed of the irradiated output and the surface on which it is irradiated. In particular, the irradiated output divided by the irradiated surface is equal to the output density. Thus, in step a) of the method according to the invention, the desired output of the laser beam and the desired cross-section of the laser beam provided on the surface of the target are determined. In other words, after step a) is executed, information about which characteristics, in particular which output density, the laser beam should have at the position of the target is available.

[0014] The next step b) involves preparing the operation of the laser light source. In particular, the laser beam is set to provide a laser beam having an initial output and an initial cross-section. Here too, the initial output and the initial cross-section define an initial output density. The initial output or the initial cross-section, or both of them, can preferably be set based on the desired output and / or the desired cross-section determined in step a). This makes it possible to minimize the corrections and adjustments that need to be made due to the need for beam adjustment to provide the desired output and the desired cross-section in the target. Furthermore, setting the initial output and / or the initial cross-section to different values contributes to the range of variation of the output density that can be provided by a laser system operated by the method according to the invention.

[0015] In the third step c), an important part of the adjustment of the laser beam is prepared.

[0016] Within the adjustment means, the laser beam first passes through a first adjustment unit and then through a clipping aperture. The first adjustment unit can at least change the cross-section of the laser beam. In other words, since the total output of the laser beam remains essentially constant at the initial output set by the laser light source, the change in the cross-section of the laser beam provided by the first adjustment unit essentially sets the output density of the laser beam impinging on the clipping aperture. Thereby, the laser output impinging on the clipping aperture and being irradiated as a result can be adjusted.

[0017] Additionally or alternatively, the clipping aperture, in particular the clipping aperture itself, strongly influences the size of a part of the laser beam still available after the clipping aperture.

[0018] Thus, by both changing the size of the cross-section of the laser beam impinging on the clipping aperture and changing the size of the clipping aperture respectively, the amount of laser output still included by the laser beam after the clipping aperture can be adjusted.

[0019] In step c), the first adjustment part and / or the clipping aperture are set such that the output included in the laser beam after the clipping aperture is an intermediate output that matches the desired output determined in step a). In the context of the present invention, the intermediate output is selected such that the laser beam can ensure that it contains, at least preferably exactly, the desired output at the target. Thus, the intermediate output is preferably selected to be slightly larger than the desired output in order to compensate for the output loss between the clipping aperture and the target.

[0020] The next step d) relates to the second adjustment part. After the clipping aperture, the laser beam includes the intermediate output, and the cross-section of the laser beam is defined by the size and cross-section of the clipping aperture. Thus, the second adjustment part is mainly used to change the cross-section of the laser beam from the size of the clipping aperture to the desired cross-section of the laser beam at the target. As described above, the possible output loss of the laser beam between the clipping aperture and the target can already be addressed by setting the intermediate output accordingly.

[0021] In summary, after step d), in particular, a complete laser system including a laser light source, a first adjustment part, a clipping aperture, and a second adjustment part is easily set to provide a laser beam having a desired output, a desired cross-section, and thus a desired output density at the target.

[0022] Therefore, after the completion of the setting procedures for steps b), c), and d) respectively, in the final mandatory step e) of the method according to the present invention, the laser beam is actually provided to the target with both the desired output and the desired cross-section, and thus at the desired output density. In particular, due to the interaction between the variations in the laser output and cross-section already provided by the laser light source and the large potential variations in the laser output remaining after the clipping aperture, it is possible to easily provide a dynamic range of the output density of more than 1000 between the lowest achievable output density and the highest achievable output density. For example, for a circular cross-section and a clipping aperture, a change in the radius of the cross-section or aperture by a factor of 2 results in a change in the respective area and thus a change in the output density by a factor of 4. In particular, the above-mentioned variations in the laser output remaining after the clipping aperture are essentially limited only by the beam expansion ability of the first adjustment unit and the size limit of the clipping aperture due to the manufacturing accuracy and integral stability of the clipping aperture.

[0023] Furthermore, the method according to the present invention can be characterized in that the intermediate output of the laser beam provided after the clipping aperture corresponds to the sum of the desired output and the expected output loss in the second adjustment unit. As described above, the intermediate output is selected such that the laser beam contains at least the desired output when irradiating the target. By setting the intermediate output to the sum of the desired output in the second adjustment unit and the expected output loss, it is possible to accurately provide the output of the laser beam at the target with the desired output and avoid irradiating the target with excessive output.

[0024] In addition, the method according to the present invention can include setting the initial output in step b) to 10% - 100%, particularly 5% - 100%, preferably 3% - 100% of the maximum output achievable by the laser light source. Thereby, the laser light source can contribute more than 10 times, particularly more than 20 times, preferably more than 30 times to the range of achievable output density.

[0025] According to one embodiment of the method according to the invention, in step c), the first adjustment unit is set to expand the cross-section of the laser beam in order to reduce the proportion of the laser irradiated through the clipping aperture. The maximum value of the laser output irradiated through the clipping aperture of the clipping aperture can be achieved by providing a focused laser beam that is completely irradiated through the clipping aperture. By expanding the cross-section of the laser beam by the first adjustment unit, the total output of the laser beam spreads over a wider area. At the same time, the portion of the laser beam that impinges on the bulk of the clipping aperture and thereby lacks the clipping aperture increases with the size of the cross-section of the laser beam. Therefore, by changing the cross-section of the laser beam by the first adjustment unit, the final output given to the target can be easily adjusted.

[0026] Additionally or alternatively, the method can be characterized in that in step c), the clipping aperture is set to reduce the clipping aperture in order to reduce the proportion of the laser beam passing through the clipping aperture. As already mentioned above, the maximum value of the laser output irradiated through the clipping aperture of the clipping aperture can be achieved by providing a focused laser beam that is completely irradiated through the clipping aperture. By reducing the size of the clipping aperture, the proportion of the laser beam irradiated through the clipping aperture can be similarly reduced. Therefore, by changing the size of the clipping aperture, the final output provided at the target can be easily adjusted.

[0027] Preferably, the method according to the invention includes both of the above possibilities, namely, adjusting the cross-section of the laser beam impinging on the clipping aperture by the first adjustment unit and adjusting the size of the clipping aperture, respectively. The effects of both measurements on the final output that can be provided are summed, preferably multiplied.

[0028] In particular, the method according to the invention can be improved by the fact that the proportion of the laser beam irradiated through the clipping aperture is less than 100% to less than 3%, in particular less than 100% to less than 2%, preferably less than 100% to less than 1% of the laser beam impinging on the clipping aperture. As already explained, said proportion can be varied by adjusting the cross-section of the laser beam impinging on the clipping aperture and / or by adjusting the size of the clipping aperture. The beam adjustment means, in particular the first adjustment part and the clipping aperture, contribute to a range of available output densities that exceeds 30 times, in particular exceeds 50 times, preferably exceeds 100 times.

[0029] Considering that the laser light source can also contribute to a range of available output densities of 10 times, in particular 20 times, preferably 30 times, the entire range of available output densities exceeding 300 times to preferably exceeding 3000 times can be provided by operating the laser system by the method according to the invention.

[0030] In addition, the method can be further enhanced in that in an additional step f), the output and / or cross-section of the laser beam provided in step e) is monitored, compared with the desired output and / or the desired cross-section respectively, and the result of said comparison is used for feedback-based adjustment of the execution of step b) and / or step c) and / or step d). Said monitoring can be provided, for example, by direct or indirect temperature measurement of the target, preferably spatially resolved temperature measurement. Also, detecting the laser beam reflected on the target can be used for such monitoring of the characteristics of the laser beam impinging on the target. By performing feedback-based adjustment of the execution of step b) and / or step c) and / or step d) based on said monitoring, it is possible to ensure that a laser beam with a desired output and a desired cross-section is provided that is constant over time.

[0031] The output and / or cross-section of the laser beam provided in step e) are each monitored, compared with a desired output and / or a desired cross-section, and the result of this comparison is used for feedback-based adjustment of the execution of step b) and / or step c) and / or step d). Said monitoring can be provided, for example, by direct or indirect temperature measurement of the target, preferably spatially resolved temperature measurement. Also, detecting the laser beam reflected on the target can be used for such monitoring of the characteristics of the laser beam impinging on the target. By performing a feedback-based adjustment of the execution of step b) and / or step c) and / or step d) based on said monitoring, it is possible to ensure that a laser beam with a desired output and a desired cross-section that are constant over time is provided.

[0032] According to a second aspect of the invention, said object can be achieved by a laser system for heating and / or evaporating and / or sublimating a target arranged in a reaction chamber of an evaporation system, said laser system comprising a laser light source for providing a laser beam, said laser system comprising beam adjustment means along said laser beam, comprising a first adjustment unit, a clipping aperture having a clipping opening, and a second adjustment unit. The laser system according to the second aspect of the invention is characterized in that the laser system is configured to carry out the method according to the first aspect of the invention. Thus, the laser system according to the second aspect of the invention provides all the advantages described above with respect to the method according to the first aspect of the invention.

[0033] In particular, by implementing the method according to the invention, the laser system according to the invention can also provide the full range of available output densities on the surface of the target that exceeds 300 times, preferably exceeds 3000 times.

[0034] The laser system according to the invention can be used in an evaporation system, in particular for TLE applications. The laser system provides a laser beam, which is also preferably used in the evaporation system. The laser beam can be used to evaporate and / or sublime a target, for example a source material. Alternatively or additionally, the laser beam can also be used only to heat a substrate that is coated with the evaporated and / or sublimated material of the target, for example. The target is arranged in a reaction chamber, in particular in a reaction volume surrounded by the reaction chamber.

[0035] In addition to the laser light source, the laser system includes beam adjustment means for changing the characteristics of the laser beam, in particular for changing at least the cross-section of the laser beam. The beam adjustment means has three forcing parts, namely a first adjustment part, a clipping aperture, and a second adjustment part, respectively, particularly along the direction of the laser beam. The clipping aperture preferably includes a clipping opening at the center of the laser beam. The material of the clipping aperture is preferably opaque or at least essentially opaque to the laser beam. Thus, the clipping aperture can clip the laser beam very effectively.

[0036] In particular, the laser system according to the invention can include being configured to actively adjust the initial output and the initial cross-section of the laser beam provided by the laser light source. Thereby, a first contribution to the range of available output densities at the surface of the target can already be provided by the laser light source. The laser light source can include, for example, laser adjustment means for changing the initial output and / or built-in optical elements for changing the initial cross-section. The ability to actively adjust the initial output and the initial cross-section of the laser beam enables the use of the same laser light source to provide different initial outputs and initial cross-sections of the laser beam, respectively. Thereby, the need to replace the laser light source for changing the initial output and the initial cross-section can be avoided.

[0037] Further, the laser system according to the present invention can be characterized in that the first adjustment unit is configured to actively adjust the cross-section of the laser beam that collides with the clipping aperture. In this embodiment, the first adjustment unit contributes to the range of available output density on the surface of the target. The ability to actively adjust the cross-section of the laser beam that collides with the clipping aperture allows the same first adjustment unit to be used to provide different cross-sections of the laser beam in the clipping aperture. The active adjustment can be provided, for example, by an adjustable lens, mirror, or similar optical element. Implementation of a beam expander and / or a beam compressor is also possible. This can avoid the need to replace the first adjustment unit for changing the cross-section of the laser beam that collides with the clipping aperture.

[0038] Additionally or alternatively, the laser system according to the present invention can include an actuator for the clipping aperture to actively adjust the size of the clipping opening. In this embodiment, the clipping aperture itself contributes to the range of available output density on the surface of the target. The ability to actively adjust the size of the clipping opening by the actuator allows the same clipping aperture to be used to provide clipping openings of different sizes. The active adjustment can be provided, for example, by a iris diaphragm driven by an actuator. This can avoid the need to replace the clipping aperture for changing the size of the clipping opening.

[0039] According to a preferred embodiment, the laser system according to the present invention comprises at least two, particularly three, of the following actively adjustable elements: · An actively adjustable laser light source · An actively adjustable first adjustment unit · An actively adjustable clipping aperture By providing two, preferably three, of said adjustable elements, it is possible to combine and provide the features and advantages described above for each element.

[0040] Furthermore, the laser system according to the invention can include that the laser system comprises cooling means for cooling the clipping aperture. The clipping aperture is used to block a portion of the laser beam that impinges on the clipping aperture. Thus, the energy of the blocked portion of the laser beam can be at least partially absorbed by the bulk of the clipping aperture. By providing cooling means, most of the clipping aperture can be cooled, and the energy absorbed from the impinging laser beam can be carried away. Thereby, in the worst case, overheating of the clipping aperture, which could lead to a breach of the structural integrity of the clipping aperture, can be avoided.

[0041] In addition, the laser system according to the invention can be enhanced by the clipping aperture comprising and preferably consisting of copper and / or aluminum alloy. Copper and aluminum have relatively high thermal conductivities of up to ~400 W / mK (copper) and up to ~235 W / mK (aluminum alloy). Thus, the temperature rise of the clipping aperture is particularly well distributed throughout the clipping aperture, making it easier to provide effective cooling of the clipping aperture by the cooling means.

[0042] Furthermore, the laser system according to the present invention can include that an upstream surface of a clipping aperture facing a laser beam is provided with an absorption layer for absorbing the laser beam. By providing such an absorption layer, for example, by rough plasma spraying coating the upstream surface of the clipping aperture, the ability of the upstream surface of the clipping aperture to absorb the impinging laser beam can be dramatically enhanced. Thereby, it is possible to avoid uncontrolled and unintentional reflections of the laser beam on the surface of the clipping aperture, damage to the laser system, evaporation system, and / or the surroundings.

[0043] In addition, the laser system can be enhanced by the absorption layer having a thickness of 100 μm to 500 μm and / or including aluminum oxide, preferably consisting of aluminum oxide. The thickness of the absorption layer of 100 μm to 500 μm has been found to be very effective in absorbing the impinging laser beam. Furthermore, aluminum oxide provides good to excellent absorption ability, especially for laser beams having a wavelength of about 10 μm.

[0044] According to an alternative embodiment, the laser system according to the present invention can be characterized in that an upstream surface of a clipping aperture facing a laser beam is reflective with respect to the laser beam and / or is provided with a reflective layer that is reflective with respect to the laser beam. In contrast to the above-mentioned uncontrolled and unintentional reflections, the impinging laser beam can also be reflected onto the upstream surface of the clipping aperture in a controlled and intentional manner. For example, for very high laser energy and / or density, the absorption of the impinging laser beam by the clipping aperture may damage, and even melt, the bulk material of the clipping aperture. Therefore, by preferably controllably and intentionally reflecting the impinging laser beam, it is possible to avoid absorbing an excessive amount of laser energy, and thus reduce the risk of damage to the clipping aperture.

[0045] Furthermore, the laser system according to the present invention can be enhanced by arranging at least a part of the upstream surface, preferably the entire upstream surface, at an angle greater than 90°, preferably greater than 95°, with respect to the laser beam. The laser beam reflected back to the laser light source may cause serious damage to the laser light source. By providing an angle greater than 90°, preferably greater than 95°, it is possible to ensure that the laser beam reflected from the upstream surface is not reflected in the direction of the incident laser beam and thus not in the direction towards the laser light source. In addition, by providing the upstream surface at an angle with respect to the laser beam, it becomes possible to control, for example, the direction of the reflected laser beam towards a dedicated laser beam dump. Preferably, the upstream surface can be formed as a cone, particularly a truncated cone.

[0046] Alternatively or additionally, the laser system according to the present invention can be enhanced by arranging at least a part of the upstream surface, preferably the entire upstream surface, at an angle less than 90°, preferably less than 85°, with respect to the laser beam. As already pointed out above, the laser beam reflected back to the laser light source may cause serious damage to the laser light source. By providing an angle less than 90°, preferably less than 85°, it is possible to ensure that the laser beam reflected from the upstream surface is not reflected in the direction of the incident laser beam and thus not in the direction towards the laser light source. In addition, by providing the upstream surface at an angle with respect to the laser beam, it becomes possible to control, for example, the direction of the reflected laser beam towards a dedicated laser beam dump. Preferably, the upstream surface can be formed as a cone, particularly a truncated cone.

[0047] In another embodiment, the laser according to the present invention can include providing a laser beam in which the laser light source and / or the first adjustment unit are at least essentially parallel. Parallel laser beams can be beneficial, especially because the distance between optical elements can be varied without changing the characteristics of the laser beam. For example, the laser light source can be placed at a distance from the rest of the laser system that can be assembled in the reaction chamber of the evaporation system, especially in different rooms or different buildings. This can improve the flexibility with respect to the setting of the laser system according to the present invention.

[0048] Further, the laser system according to the present invention can be characterized in that the second adjustment unit includes a condenser lens that condenses the laser beam toward the surface of the target. The focusing lens, as part of the second adjustment unit after the clipping aperture, provides a focal point and images the laser beam on the working plane where the target is located, particularly regardless of the size of the clipping aperture. In the scope of the present invention, focusing the laser beam toward the surface of the target includes both directly focusing it on the target surface and focusing it between the target surface and the focusing lens. In the first case, the focal volume representing the minimum extent of the beam is located on the target surface or at least in its vicinity, and in the latter case, the focal volume is arranged somewhere between the focusing lens and the target surface. Thereby, the actual position of the focal volume can be selected according to the boundary conditions existing in each evaporation system.

[0049] In yet another embodiment, it can include that with the laser system according to the present invention being mounted, the beam adjustment means is at least partially arranged within the reaction chamber. Since the target is also arranged within the reaction chamber, in the ascending part or the whole of the second adjustment part, additionally a clipping aperture and further additionally a part or the whole of the first adjustment part are arranged within the reaction chamber. Generally speaking, since the reaction chamber requires a certain structural space anyway, arranging a part of the adjustment means within the reaction chamber helps to reduce the structural space required for the entire evaporation system.

[0050] In addition, the laser system according to the present invention comprises a shielding aperture having a shielding opening with the second adjustment part arranged within the reaction chamber, and the focal volume of the laser beam can be enhanced by being arranged at the shielding opening. In other words, the shielding aperture is arranged within the reaction chamber, between the coupling means within the chamber wall of the reaction chamber, for example, between the chamber window and the target. In particular, the focal volume of the laser beam, which preferably represents the minimum range of the laser beam along its path and is generated by a focusing lens as a part of the second adjustment part, is arranged at the shielding opening of the shielding aperture. Thereby, except for the shielding opening, the direct line of sight between the target surface and the coupling means is almost completely blocked. Therefore, most of the substance of the target evaporated and / or sublimated by the colliding laser beam collides with the shielding aperture, and the coupling means is protected from an unintended coating. Thereby, the service life of the coupling means can be significantly extended.

[0051] In yet another embodiment, the laser system can be characterized in that the beam adjustment means is arranged outside the reaction chamber along the laser beam at least up to the focusing lens. The focusing lens is a part of the second adjustment part. That is, the complete first adjustment part and the clipping aperture are arranged outside the reaction chamber, as set in step c) of the method according to the first aspect, which are two parts of the beam adjustment means used for clipping the laser beam and are thus easily accessible.

[0052] Furthermore, in most embodiments of the evaporation system, the focusing lens is located externally, yet it is positioned at a short distance from the coupling means of the reaction chamber. Immediately after the focusing lens, the cross-section of the laser beam is still relatively large, and thus the output density is low respectively. As a result, the heating of the coupling means is reduced and the operating time is lengthened.

[0053] Furthermore, the laser system according to the present invention can be provided with the first adjustment unit and / or the second adjustment unit comprising one or more of the following optical elements: · Focusing lens and / or mirror · Defocusing lens and / or mirror · Freeform mirror · Beam expander · Beam compressor · Focusing axicon · Defocusing axicon This list is not closed, and other optical elements as part of the first adjustment unit and / or the second adjustment unit are also possible. By implementing different optical elements, a wide range of possible parameters of the laser beam at the target surface can be provided, such as the overall shape or the spatially dependent intensity distribution.

[0054] According to another embodiment, the laser system can be characterized in that it comprises one or more additional secondary beam adjustment means arranged in series continuously along the laser beam after the beam adjustment means. Similar to the above-described beam adjustment means, each of the one or more additional secondary beam adjustment means also comprises a first adjustment unit, a clipping aperture, and a second adjustment unit respectively. Also, the functions of these components are the same as those of the components of the adjustment means described above. Therefore, each of the secondary adjustment means receives an incident laser beam having an initial output and an initial cross-section, and provides a laser beam having a desired output and a desired cross-section, whereby the initial output and the initial cross-section correspond to the desired output and the desired cross-section of the previous beam adjustment means along the laser beam. The last secondary beam adjustment means finally provides a laser beam having a desired output and a desired cross-section on the surface of the target. In summary, by arranging several beam adjustment means in series along the path of the laser beam, the entire output density range available for each of the beam adjustment means is doubled. For example, if a single secondary beam adjustment means having an available range of factors exceeding 250 times is used in series with a beam adjustment means having an available range of factors exceeding 500 times, a range of laser output with an available factor exceeding 125000 times can be provided as a whole.

[0055] According to a third aspect of the present invention, an evaporation system for coating a substrate with an evaporated and / or sublimated material of a source, comprising a reaction chamber having a reaction volume for arranging the source and the substrate, a substrate laser system for heating the substrate, and / or a source laser system for evaporating and / or sublimating the material of the source, can achieve the object. The evaporation system according to the third aspect of the present invention is characterized in that the substrate laser system and / or the light source laser system is the laser system according to the second aspect of the present invention. In other words, the substrate laser system and / or the source laser system can be used to execute the method according to the first aspect of the present invention. Therefore, the evaporation system according to the third aspect of the present invention provides all the advantages described above with respect to the laser system according to the second aspect of the present invention and also with respect to the method according to the first aspect of the present invention.

[0056] Hereinafter, the present invention will be specifically described with reference to embodiments and the drawings showing the embodiments.

Brief Description of the Drawings

[0057]

Figure 1

Figure 2

Figure 3

Figure 4

[0058] Figure 1 schematically shows a possible embodiment of an evaporation system 100 according to the present invention. The evaporation system 100 comprises a laser system 10 according to the present invention, which is used to heat a target 120, in particular a substrate 126 to be coated. Both the evaporation system 100 and the laser system 10 are each configured to execute a method according to the present invention. The target 120 is arranged within a reaction chamber 110, in particular within a reaction volume 112 surrounded by the reaction chamber 110.

[0059] In the illustrated embodiment, the laser system 10 is arranged completely outside the reaction chamber 110. The laser system 10 comprises at least a laser light source 12 and beam adjustment means 40, the latter comprising at least a first adjustment unit 42, a clipping aperture 70, and a second adjustment unit 44. The laser beam 20 irradiated by the laser system 10 is guided into the reaction chamber 110 via coupling means 114 arranged on the chamber wall 116 of the reaction chamber 110. The coupling means 114 is, for example, a chamber window.

[0060] The object of the present invention is to provide a laser beam 20 having a desired output 28 and a desired cross-section 30 on the surface 122 of the target 120. Hereinafter, the method according to the present invention will be described based on the embodiment of the evaporation system 100 shown in Figure 1. However, this description is merely illustrative and does not limit the content of the present invention.

[0061] In a first step a) of the method according to the present invention, the desired output 28 and the desired cross-section 30 are determined. The desired output 28 and the desired cross-section 30 are preferably selected suitable for the purpose of the laser beam 20, i.e., on the one hand for heating and on the other hand for evaporating and / or sublimating. Furthermore, when determining the desired output 28 and the desired cross-section 30, the material to be heated, evaporated or sublimated can be considered respectively. The determined values are then used to set the laser system 10 and thus the complete evaporation system 100.

[0062] First, in step b) of the method according to the present invention, the laser light source 12 of the laser system 10 is set to provide a laser beam 20 having an initial output 24 and an initial cross-section 26. Preferably, the initial output 24 is set to 10% - 100%, particularly 5% - 100%, preferably 3% - 100% of the maximum output that can be provided by the laser light source 12. Already, by setting the initial output 24, particularly the initial cross-section 26, it is possible to provide a change in the values of the desired output 28 and the desired cross-section 30 that can be provided by the laser system 10 according to the present invention. Preferably, the laser light source 12 is configured to actively adjust the initial output 24 and the initial cross-section 26, enabling the use of the same laser light source 12 to provide laser beams 20 having different initial characteristics.

[0063] Along the direction of the laser beam 20, the next element of the laser system 10 is the first adjustment unit 42. The first adjustment unit 42 can at least change the cross-section 22 of the laser beam 20, and in particular can expand the cross-section 22. By expanding the cross-section 22, the total output of the laser beam 20 is essentially not affected, and thus the output density of the laser beam 20 can be changed, in particular reduced. In other words, the proportion of the total output of the laser beam 20 that impinges on a specific area can be adjusted, in particular reduced.

[0064] Preferably, the adjustment of the cross-section 22 of the laser beam 20 described above can be actively performed by the first adjustment unit 42. The active adjustment can be provided, for example, by an adjustable lens, mirror, or similar optical element. By actively adjusting the laser beam 20 by the first adjustment unit 42, it becomes possible to use the laser system 10 according to the present invention for different desired outputs 28 and / or desired cross-sections 30 without the need to replace the first adjustment unit 42.

[0065] As shown, both the laser light source 12 and the first adjustment unit 42 each provide a laser beam 20 that is at least essentially parallel. Thus, the distances between the laser light source 12 and the first adjustment unit 42, and between the first adjustment unit 42 and the clipping aperture 70, do not affect or at least essentially do not affect the optical characteristics of the laser system 10.

[0066] Also in this case, after the first adjustment unit 42, a clipping aperture 70 is arranged along the path of the laser beam 20. The clipping aperture 70 includes a clipping opening 72. In most cases, the clipping opening 72 has a size smaller than that of the laser beam 20 after passing through the first adjustment unit 42. Thus, only a part of the colliding laser beam 20 passes through the clipping opening 72, and the remaining laser beam 20 collides with the upstream surface 74 of the bulk of the clipping aperture 70. As shown, the clipping aperture 70 can be provided with an actuator 80 for actively adjusting the size of the clipping opening 72. Thus, the aforementioned ratio of the laser beam 20 passing through the clipping aperture 70 can also be adjusted by the clipping aperture 70 itself.

[0067] In the illustrated embodiment, the upstream surface 74 is coated with an absorption layer 76 for absorbing the laser beam 20, for example, by rough plasma spraying the upstream surface 74 of the clipping aperture 70. Preferably, the absorption layer 76 has a thickness of 100 μm to 500 μm. Additionally or alternatively, the absorption layer 76 contains aluminum oxide and preferably consists of aluminum oxide. Absorbing the colliding laser beam 20 by the absorption layer 76 helps to avoid damage to the laser system 20, the evaporation system 100, and / or the surroundings due to uncontrolled and unintended reflection of the laser beam 20 on the upstream surface 74 of the clipping aperture 70.

[0068] Since the energy of the absorbed laser beam 20 heats the bulk volume of the clipping aperture 70, cooling means 82 for cooling the clipping aperture 70 is provided. For example, in the case of a laser beam 20 having a very high laser energy and / or density, the absorption of the impinging laser beam 20 by the clipping aperture 70 may damage the bulk material of the clipping aperture 70 and even melt it. By actively cooling the clipping aperture 70 by the cooling means 82, the said danger is prevented. The thermal conductivity of the clipping aperture 70 can be increased by a clipping aperture 70 containing copper and / or an aluminum alloy, preferably consisting of copper and / or an aluminum alloy.

[0069] As described above, the first adjustment unit 42 gives a constant output density to the laser beam 20. In addition, the size of the clipping aperture 72 defines the proportion of the impinging laser beam 20 passing through the clipping aperture 70. In summary, these two elements of the laser system 10 according to the invention define the proportion of the total output of the laser beam 20 still present after the clipping aperture 70. Preferably, the said proportion of the laser beam 20 irradiated through the clipping aperture 72 is provided at less than 100% to less than 3%, in particular less than 100% to less than 2%, preferably less than 100% to less than 1% of the laser beam 20 impinging on the clipping aperture 70. Considering that the laser light source 12 can also contribute to a range of output densities that can be provided by 10 times, in particular 20 times, preferably 30 times, the entire range of output densities that can be provided by more than 300 times, preferably more than 3000 times, can be provided by operating the laser system 10 according to the invention by the method according to the invention.

[0070] In particular, this remaining output of the laser beam 20 is provided in step c) of the method according to the invention by setting the said elements of the laser system 10 and by defining the interaction between the first adjustment unit 42 and the clipping aperture 70. In particular, the laser beam 20 comprises an intermediate output 32 which is selected such that the laser beam 20 can ensure that it contains at least, preferably exactly, the desired output 28 at the target. Preferably, the intermediate output 32 is selected such that the expected output loss of the laser beam 20 along its path between the clipping aperture 70 and the target 120 is compensated, in other words such that the intermediate output 32 is equal to the sum of the desired output 28 and the said expected output loss. The associated intermediate cross-section 34 of the laser beam 20 is defined by, and corresponds to, the size of the clipping aperture 72.

[0071] Basically, except for the above-mentioned output loss, the output of the laser beam 20 is set after the clipping aperture 70. Thus, the second adjustment unit 44 arranged along the laser beam 20 between the clipping aperture 70 and the target 120 generally serves to convert the intermediate cross-section 34 of the laser beam 20 into the desired cross-section 30 of the laser beam 20 at the target 120. The setting of the second adjustment unit 44 for the said conversion of the cross-section of the laser beam 20 is provided in step d) of the method according to the invention.

[0072] Finally, in the last essential step e) of the method according to the invention, the laser light source 12 is switched on and the laser beam 20 is actually provided to the target 120. Since all the above-mentioned settings are made, i.e. the respective settings of the first adjustment unit 42, the clipping aperture 70 and the second adjustment unit 44, the laser beam 20 is provided to the surface 122 of the target 120 which has both the desired output 28 and the desired cross-section 30, respectively.

[0073] Considering that, in addition to the adjustment means 40, the laser light source 12 can contribute to the range of output densities that can be provided, the entire range of output densities that can be provided at the target exceeding 300 times, preferably exceeding 3000 times, can be provided by operating the laser system 10 according to the invention by the method according to the invention.

[0074] In addition, the method according to the invention can also include an additional step f) in which the feedback-based adjustment of the above-described settings is carried out. The feedback can be monitored, for example, by direct or indirect temperature measurement of the target 120 or by detecting the laser beam reflected at the surface 122 of the target, and can be based on comparing the actual output and / or cross-section 22 of the laser beam 20 provided to the target 120 with the desired output 28 and / or the desired cross-section 30, respectively.

[0075] In FIG. 2, the interaction between the first adjustment unit 42 (see FIG. 1) and the clipping aperture 70 is shown for two examples. In the left panel A, the laser beam 20 has a relatively low intermediate output 32, and in the right panel B, it has a relatively high intermediate output 32. In both panels A and B, the laser beam 20 has the same initial output 24, and in addition, the clipping opening 72 has the same size.

[0076] However, both panels A and B differ, in particular, by the cross-section 22 of the laser beam 20 provided by the first adjustment unit 42. In panel A, the laser beam 20 includes a relatively large cross-section 22. In contrast, in panel B, the laser beam 20 includes a relatively small cross-section 22. Thus, only a very small portion of the laser beam 20 that impinges on panel A on the upstream surface 74 of the clipping aperture 70 can pass through the clipping opening 72. In contrast, in panel B, most of the incident laser beam 20 passes through the clipping opening 72 and remains available after the clipping aperture 70 as a laser beam having a high intermediate output 32 and an intermediate cross-section 34 defined by the size of the clipping opening 72.

[0077] In addition, in contrast to the embodiment of the clipping aperture 70 shown in FIG. 1, in both panels A and B of FIG. 2, the upstream surface 74 of the clipping aperture 70 includes a reflective layer 78 and is thus reflective with respect to the laser beam 20. Thereby, the laser beam 20 impinging on the upstream surface 74 can be intentionally reflected, and by absorbing the laser beam 20, the above-mentioned drawback of heating the bulk material of the clipping aperture 70 can be avoided. In the schematic view of FIG. 2, the upstream surface 74 is arranged essentially perpendicular to the laser beam 20. However, it is preferred to arrange the upstream surface 74 at an angle different from 90°, in particular at an angle of 5° or more, or greater than 90°, with respect to the laser beam 20.

[0078] FIG. 3 shows another embodiment of the evaporation system 100 according to the invention having the laser system 10 according to the invention. In particular, FIG. 3 focuses on the second adjustment unit 44 of the laser system 10.

[0079] For clarity, the second adjustment part 44, and thus the adjustment means 40, are partially disposed within the reaction chamber 110. Outside the coupling means 114, the focusing lens 50 is disposed in proximity. The focusing lens 50 is provided after the clipping aperture 70, and thus focuses the laser beam 20 including the intermediate output 32 and the intermediate cross-section 34 towards the surface 122 of the target 120. Also, since the clipping aperture 72 is smaller than the cross-section 22 of the laser beam 20 impinging on the upstream surface 74 of the clipping aperture 70, the clipping aperture 70 blocks a part of the incident laser beam 20 including the initial output.

[0080] In the illustrated embodiment, the target 120 forms a source 124. During the evaporation and / or sublimation of the material of the source 124 by the laser beam 20, the material also propagates towards the coupling means 114. To prevent an unintended coating on the coupling means 114, in particular one that shortens the operating time, as shown, the shielding aperture 60 can be disposed within the reaction chamber 110 between the coupling means 114 and the target 120. The focal volume 36 provided by the aforementioned focusing lens 50 is disposed to coincide with the shielding aperture 62 of the shielding aperture 60. Thereby, most of the material of the source 124 moving towards the coupling means 114 is blocked by the shielding aperture 60.

[0081] Panels A, B, and C of FIG. 4 show various embodiments of the laser system 10 according to the present invention, in particular the first adjustment part 42 of the adjustment means 40. Specifically, each of the illustrated embodiments comprises axicons 56, 58 for providing a laser beam 20 having a spatially dependent output distribution as depicted in FIG. 2. Additional elements are the focusing lens 50, the beam expander 52, or the beam compressor 54. The illustrated embodiments are examples and do not limit the possible internal structure of each first adjustment part 42 of the laser system 10 according to the present invention.

[0082] In particular, in the illustrated embodiment, each first adjustment part comprises the following optical elements: Embodiment "A": Focus lens 50, beam compressor 54, first focusing axicon 56, second focusing axicon 56 Embodiment "B": Focus lens 50, beam expander 52, defocusing axicon 58, focusing axicon 56 Embodiment "C": Focus lens 50, beam compressor 54, defocusing axicon 58, focusing axicon 56 The illustrated embodiments should be understood as examples only. For example, the focusing axicon 56 in Embodiments "A", "B", and "C" can alternatively be replaced by the focus lens 50 (not shown). Further, the beam compressor 54 can also be used as the beam expander 52 when arranged in reverse with respect to the path of the laser beam 12, and vice versa.

Description of Reference Numerals

[0083] 10 Laser system 12 Laser light source 20 Laser beam 22 Cross section 24 Initial output 26 Initial cross section 28 Desired output 30 Desired cross section 32 Intermediate output 34 Intermediate cross section 36 Focus volume 40 Beam adjustment means 42 First adjustment unit 44 Second adjustment unit 50 Focus lens 52 Beam expander 54 Beam compressor 56 Focusing axicon 58 Defocusing axicon 60 Masking aperture 62 Masking opening 70 Clipping aperture 72 Clipping opening 74 Upstream surface 76 Absorbing layer 78 Reflective layer 80 Actuator 82 Cooling means 100 Evaporation system 110 Reaction chamber 112 Reaction volume 114 Coupling means 116 Chamber wall 120 Target 122 Surface 124 Source 126 Substrate

Claims

1. A method of operating a laser system (10) for providing a laser beam (20) capable of heating and / or evaporating and / or sublimating a target (120) located within a reaction chamber (110) of an evaporation system (100), the laser system (10) comprising a laser light source (12) for providing the laser beam (20) and beam adjustment means (40) for adjusting at least a cross-section (22) of the laser beam (20), the beam adjustment means (40) comprising, along the laser beam (20), a first adjustment unit (42), a clipping aperture (70) having a clipping opening (72), and a second adjustment unit (44): a) determining a desired output (28) of the laser beam (20) provided on the surface (122) of the target (120) and a desired cross-section (30) of the laser beam (20); b) setting the laser light source (12) to provide a laser beam (20) having an initial output (24) and an initial cross-section (26); c) setting the first adjustment unit (42) and / or the clipping opening (72) based on the initial output (24), the initial cross-section (26), and the desired output (28), the step of providing an intermediate output (32) that matches the desired output (28) for the laser beam (20) after irradiation through the clipping opening (72); d) setting the second adjustment unit (44) to provide the desired output (28) and the desired cross-section (30) for the laser beam (20) at the surface (122) of the target (120); e) providing the laser beam (20) by the laser light source (12) set in step b), and subsequently adjusting the laser beam (20) by the beam adjustment means (40) set in steps c) and d) to provide each of the desired output (28) and the desired cross-section (30) for the laser beam (20) set on the surface (122) of the target (120) in step a). A method comprising the above steps.

2. The method according to claim 1, wherein the intermediate output (32) of the laser beam (20) provided after the clipping opening (72) corresponds to the sum of the desired output (28) in the second adjustment unit (44) and an expected output loss.

3. The method according to claim 1 or 2, wherein in step b), the initial output (24) is set to 10% to 100%, in particular 5% to 100%, preferably 3% to 100% of the maximum output that can be provided by the laser light source (12).

4. The method according to any one of claims 1 to 3, wherein in step c), the first adjusting unit (42) is set to expand the cross-section (22) of the laser beam (20) in order to reduce the proportion of the laser irradiated through the clipping aperture (72).

5. The method according to any one of claims 1 to 4, wherein in step c), the clipping aperture (70) is set to reduce the clipping aperture (72) in order to reduce the proportion of the laser beam (20) irradiated through the clipping aperture (72).

6. The method according to claim 4 or 5, wherein the proportion of the laser beam (20) irradiated through the clipping aperture (72) is provided at 100% to less than 3%, in particular 100% to less than 2%, preferably 100% to less than 1% of the laser beam (20) impinging on the clipping aperture (70).

7. In an additional step f), the output and / or cross-section (22) of the laser beam (20) provided in step e) is monitored, compared with a desired output (28) and / or a desired cross-section (30) respectively, and the result of the comparison is used for feedback-based adjustment of the execution of step b) and / or step c) and / or step d). The method according to any one of claims 1 to 6.

8. A laser system (10) for heating and / or evaporating and / or sublimating a target (120) disposed within a reaction chamber (110) of an evaporation system (100), The laser system (10) comprises a laser light source (12) for providing a laser beam (20), The laser system (10) comprises beam adjustment means (40) along the laser beam (20), the beam adjustment means (40) comprising a first adjusting unit (42), a clipping aperture (70) having a clipping aperture (72), and a second adjusting unit (44), The laser system (10) is configured to execute the method according to any one of claims 1 to 7. Laser system (10).

9. The laser system (10) according to claim 8, wherein the laser light source (12) is configured to actively adjust an initial output (24) and an initial cross-section (26) of the provided laser beam (20).

10. The laser system (10) according to claim 8 or 9, wherein the first adjustment unit (42) is configured to actively adjust a cross-section (22) of the laser beam (20) that collides with the clipping aperture (70).

11. The laser system (10) according to any one of claims 8 to 10, wherein the clipping aperture (70) includes an actuator (80) for actively adjusting a size of the clipping opening (72).

12. The laser system (10) according to any one of claims 8 to 11, wherein the laser system (10) includes a cooling means (82) for cooling the clipping aperture (70).

13. The laser system (10) according to claim 12, wherein the clipping aperture (70) includes copper and / or an aluminum alloy, preferably consisting of them.

14. The laser system (10) according to any one of claims 8 to 13, wherein an upstream surface (74) of the clipping aperture (70) facing the laser beam (20) includes an absorption layer (76) that absorbs the laser beam (20).

15. The laser system (10) according to claim 14, wherein the absorption layer (76) includes a thickness of 100 μm to 500 μm and / or includes aluminum oxide, preferably consisting of aluminum oxide.

16. The laser system (10) according to any one of claims 8 to 13, wherein an upstream surface (74) of the clipping aperture (70) facing the laser beam (20) is reflective with respect to the laser beam (20) and / or includes a reflective layer (78) that is reflective with respect to the laser beam (20).

17. The laser system (10) according to claim 16, wherein at least a part of the upstream surface (74), preferably the entire upstream surface (74), is arranged at an angle greater than 90 °, preferably greater than 95 °, with respect to the laser beam (20).

18. At least a part of the upstream surface (74), preferably the entire upstream surface (74), is arranged at an angle smaller than 90°, preferably smaller than 85°, with respect to the laser beam (20), for the laser system (10) according to claim 16 or 17.

19. The laser source (124) and / or the first adjustment unit (42) provides a laser beam (20) that is at least essentially parallel, for the laser system (10) according to any one of claims 8 to 18.

20. The second adjustment unit (44) comprises a focusing lens (50) that focuses the laser beam (20) towards the surface (122) of the target (120), for the laser system (10) according to any one of claims 8 to 19.

21. In the mounted state, the beam adjustment means (40) is at least partially arranged within the reaction chamber (110), for the laser system (10) according to any one of claims 8 to 20.

22. The second adjustment unit (44) comprises a shielding aperture (60) having a shielding opening (62) arranged within the reaction chamber (110), and the focal volume (36) of the laser beam (20) is arranged at the shielding opening (62), for the laser system (10) according to claim 21.

23. The beam adjustment means (40) is arranged outside the reaction chamber (110) along the laser beam (20) at least up to the focusing lens (50), for the laser system (10) according to any one of claims 20 and 22.

24. The first adjustment unit (42) and / or the second adjustment unit (44) comprises one or more of the following optical elements, for the laser system (10) according to any one of claims 8 to 23: · Focusing lens (50) and / or mirror · Defocusing lens and / or mirror · Freeform mirror · Beam expander (52) · Beam compressor (54) · Focusing axicon (56) · Defocusing axicon (58).

25. The laser system (10) includes one or more additional secondary beam adjustment means arranged continuously in series along the laser beam (20) after the beam adjustment means (40), for the laser system (10) according to any one of claims 8 to 24.

26. An evaporation system (100) for coating a substrate (126) with evaporated and / or sublimated material from a source (124), the evaporation system (100) comprising a reaction chamber (110) having a reaction volume (112) for disposing the source (124) and the substrate (126), and a substrate (126) laser system (10) for heating the substrate (126) and / or a source (124) laser system (10) for evaporating and / or sublimating the material of the source (124). The evaporation system (100), wherein the substrate (126) laser system (10) and / or the source (124) laser system (10) is the laser system (10) according to any one of claims 8 to 25.

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