Control method for ion-etching, and ion beam processing system

Abstract

The invention relates to an ion beam processing system (1) for ion-etching the surface (21) of a substrate (2), comprising an ion source (11) for generating an ion beam (111) for removing surface atoms and / or impurities on the substrate surface (21) by contacting same with the ion beam (111), a positioning device (13) for positioning the ion beam (111) relative to the substrate surface (21) in order to carry out an ion etching process at a point of incidence (211) of the ion beam (141) on the substrate surface (21), and a control unit (14) for generating a control signal (141), which can be transmitted to the ion source (11) and to the positioning device (13), for controlling the positioning device (13) and the ion source (11), wherein the ion beam device (1) has a substrate holder (12) for securing the substrate (2) on a substrate plane (21) and for generating operating points (511.51i) along a path (5, [501..50i]) of the point of incidence (211) of the ion beam (111) on the substrate surface (21), the path being parallel to a second translational movement direction (312).

Description

P1512PC00 Coating system for coating substrates and corresponding process Field of invention The present invention relates to a control method for ion etching of a substrate surface of a substrate with an ion source, wherein surface atoms and / or impurities on the substrate surface are removed by contact with an ion beam of the ion source, and to a corresponding ion beam processing system for ion etching of the substrate surface. Background of the invention: Ion beam systems are mainly used in the precision manufacturing of semiconductors, optics and microstructures for micro- and macro-processing of substrate surfaces to enable ablation, smoothing, modification or structuring of the substrate surface. In micromachining, ion beams are used for precise etching, for example of integrated circuits, the production of photomasks, and prototype manufacturing in microelectronics with resolutions below 0.1 m. Focused ion beams (FIBs) are also used for sample preparation in electron microscopy and the analysis of biological structures such as viruses. For macro surfaces, ion beams are suitable for planarizing large substrates (e.g. 300 mm), for smoothing X-ray mirrors or aspherical lenses. Additional applications include surface modification through ion implantation in semiconductors and metals, non-reflective coatings on solar cells, and UV lithography optics. These processes benefit from vacuum conditions for oxidation-sensitive substrate materials. Conventional ion beam processing systems comprise an ion source for generating an ion beam, a positioning device for positioning the ion beam relative to the substrate surface to be processed (where a point of impact of the ion beam is positioned relative to the substrate surface by the positioning device), and a control unit for generating a control signal that can be transmitted to the ion source and the positioning device to control the positioning device and regulate the ion source. The positioning device enables the processing of planar, spherical, and near-spherical substrate surfaces, for example, to correct geometric irregularities in order to optimize the surface properties of the substrate or to match a desired surface profile. To achieve optimal results, the ion beam must be positioned at a defined angle at the point of impact on the substrate surface during processing, for example, perpendicular to the substrate surface. To ensure this, a positioning device is provided for moving and positioning the ion source. It is known to use a multi-axis positioning device for processing substrates with ion beams, for example, a three-axis positioning device that enables movement along three translational axes, particularly those orthogonal to each other. Such a positioning device is easy to control; however, with three-axis positioning devices, it is not possible to process the substrate at a defined angle at the point where the ion beam strikes the substrate surface, which leads to inaccurate processing of the substrate surface. To a certain extent, it is possible to compensate for this inaccuracy by correcting the control signal. However, this restricts the geometry, more precisely, any potential curvature of the substrate to be processed. In addition, three-axis processing results in asymmetrical distributions of at least some geometric parameters, such as microroughness.Three-axis machining does not provide sufficient results when high accuracy is required or when machining relatively curved substrate surfaces. Using a five-axis positioning device enables more precise positioning. The more precise processing of the substrate surface by the ion beam at the point of impact on the substrate surface, however, requires a stable and highly accelerated design of all five axes of the positioning device and accordingly generates higher demands on the computing power of the control unit and a stable and efficient mechanical design of the positioning device and its actuators of the five axes. Conventional ion beam processing systems have the disadvantages that they either lead to inaccurate processing of the substrate surface or to a higher complexity of the control unit, increased costs and increased susceptibility to cumulative mechanical errors in five- or multi-axis positioning devices. Summary of the invention It is an object of the present invention to solve the disadvantages and technical problems known from the prior art. In particular, the present invention aims to provide a new device or control method for ion etching a substrate surface with an ion source, wherein the control of the positioning device and the ion source is optimized, thereby simplifying the design of the positioning device of the ion beam processing system. The more axes a positioning device comprises, the more time-consuming the calculations to be performed by the control device become, and conversely, increased costs and a greater susceptibility to cumulative mechanical errors result. According to the present invention, these objectives are achieved in particular by the elements of the characterizing part of the independent claims. Further advantageous embodiments are also apparent from the dependent claims, the drawings, and the description. In particular, these objectives are achieved by the invention through the control method according to the invention for ion etching of a substrate surface. of a substrate with an ion source by fixing the substrate to a substrate holder in a substrate plane, wherein the ion beam is positioned relative to the substrate surface along a first, second and third translational axis of motion by means of the positioning device, wherein the first and second translational axes of motion are orthogonal to each other and lie in a plane parallel to the substrate plane, and wherein the third translational axis of motion is orthogonal to the substrate plane, and wherein the ion beam is pivotable about a first and second axis of rotation perpendicular to the ion beam originating from the ion source as the point of rotation, wherein the first axis of rotation has a plane of rotation of the ion beam parallel to the first direction of motion and the second axis of rotation has a plane of rotation of the ion beam orthogonal to the first axis of rotation;Generating work points along a path parallel to the second translational direction of motion of the point of impact of the ion beam on the substrate surface; generating surface parameter values ​​for each of the generated work points based on a geometry of the substrate and / or a material of the substrate surface and / or a removal rate of the substrate surface and / or removal parameter values ​​of the ion beam and / or a material thickness to be removed relative to the third axis of motion at the respective work point; generating a first swivel angle at the point of impact for each of the work points along the path based on the generated surface parameters, wherein the first swivel angle is defined by the angle between the third axis of motion and the ion beam in the plane formed by the second and third axes of motion;Generating a second identical swivel angle at the point of entry for all work points along the path based on the generated surface parameters, wherein the second swivel angle is defined by the angle between the third axis of motion and the ion beam in the plane formed by the first and third axes of motion;and ion beam etching along the path, wherein the control signal is generated based on the path defined by the generated operating points, the generated surface parameters, and the generated first and second swivel angles, and wherein the positioning of the point of impact of the ion beam relative to the substrate surface is controlled by the positioning device in the first, second, and third translational axes of movement as well as around the first and second rotational axes by means of the control signal transmitted to the positioning device, such that the positioning device is five-axis, but only three axes are controlled; During ion beam etching, the positioning axes move along a path, while the two other axes of the five-axis kinematic positioning device serve only as feed axes. Since the feed axes and their actuators need to be less powerful, especially in terms of acceleration, they are correspondingly less prone to malfunctions. By controlling only three axes—the second axis of motion, the third axis of motion, and the first swivel angle—of the five-axis kinematic system simultaneously via the control unit during substrate surface machining along the path, the complexity of generating the control signal and processing the data is reduced, thus minimizing axis positioning errors. Furthermore, the feed axes can be designed with higher stiffness, resulting in reduced vibration and extended machine lifespan. Additionally, the feed axes can be configured with stiffer connections offering improved damping. Simultaneously, continuous processing of the substrate surface along the path is possible under a generated initial identical swivel angle. This results in more precise processing results because the alignment of the ion beam to the substrate surface at the point of impact is very precise, thus minimizing variations in the ablation rate that arise at oblique angles due to angle-dependent ablation rates. This enables precise positioning of the point of impact on the substrate surface in the nanometer range without creating new damage, and therefore precise ablation. The work points generated along the path define a straight line along which the positioning device positions the point of impact of the ion beam. In another embodiment, the work points are spaced a fraction of the ion beam's length apart from adjacent work points. In one implementation variant, a spherical surface is generated based on the operating points, whereby the generated spherical surface can exhibit a minimal deviation from the substrate surface. Furthermore, based on the generated spherical surface and the operating points, a function is applied to each of the A corresponding spherical work point is generated for each work point. Based on these corresponding spherical work points, a second identical swivel angle is generated at the point of impact for all work points along the path. This ensures that the first identical swivel angle for all work points on the path has an optimal alignment with the substrate surface being processed by the ion beam, even though the second swivel angle is identical for all work points along the path. The orthogonal positioning of the ion beam by the positioning device is easier and more precise to calculate at the generated spherical work point relative to the work points, with only a very small error resulting from the approximation of the spherical surface to the substrate surface.The geometry of the spherical surface can be modeled with small deviations from the substrate surface using a so-called "best-fit" method with known techniques, such as an oscillating sphere or least-squares calculation. In one embodiment of the present invention, a predefined specification of the spherical geometry is loaded into the control unit via an interface and acquired as surface parameter values ​​to generate the surface parameter values ​​and / or operating points. In another implementation variant, the spherical operating points are generated by the intersection of the spherical surface with the straight line running through the respective operating point orthogonal to the substrate surface at the operating point, so that the spherical points on the generated spherical surface run along a straight path, so that the generation of the first identical swivel angle at the point of entry is approximated with high accuracy for all operating points along the path. In one implementation variant, a residence time of the ion beam is generated for each operating point based on a target thickness and an actual thickness at the respective operating point, as well as the ablation rate of the substrate surface and / or the beam parameter values ​​of the ion beam. This allows the ablation rate to be generated by the ion beam for each operating point on the substrate surface to control the ion source based on the target thickness and the actual thickness, or a material thickness to be ablated at the respective operating point and beam parameters, in order to use the ion beam to remove the difference to remove material between the actual thickness and the target thickness at the operating point from the substrate surface using the ion beam. In another embodiment, the alignment position of at least two marker points arranged on the substrate surface relative to the ion beam is measured based on the axes of movement. This allows the control unit to precisely determine and control the position of the substrate surface for positioning the ion beam at the point of impact using the positioning device, based on the alignment position of the at least two marker points. For alignment purposes, cameras can be used, for example, to detect the fixed points on the substrate surface. In another embodiment, work points are generated along several paths parallel to the first translational direction of movement of the ion beam's point of impact on the substrate surface. These parallel paths are connected by connecting segments, forming a meandering process path. The work points generated along these spaced paths create a kind of three- or two-dimensional grid. This meandering design of the process path for positioning the ion beam on the substrate surface ensures efficient processing of the work points by means of the ion beam along the process path. In one embodiment, adjacent paths are spaced a fraction of the ion beam's diameter at its point of impact. In another embodiment, the control signal is generated based on the path defined by the generated operating points and the generated surface parameter values. The beam parameter values ​​are controlled by the ion beam source via an ion beam control system using the control signal transmitted to the ion source, so that the ion beam generated by the ion beam source precisely removes or etches a predefined material thickness at the point of impact. In a further embodiment, at least an ion beam velocity and / or a pulse rate of the ion beam and / or an etch rate of the ion beam are generated and, based on the The ion beam speed and / or etch rate and / or pulse rate of the ion beam generates the control signal through the control unit. In particular, the aforementioned objectives are achieved by the invention through the ion beam processing system according to the invention for ion etching a substrate surface of a substrate with an ion source for generating an ion beam for removing surface atoms and / or impurities from the substrate surface, characterized in that the ion beam processing system has a substrate holder for fixing the substrate in a substrate plane, wherein the positioning device has a first, second and third translational axis of movement for positioning the ion beam relative to the substrate surface, wherein the first and second translational axes of movement are orthogonal to each other and lie in a plane parallel to the substrate plane, and wherein the third translational axis of movement runs orthogonal to the substrate plane, wherein the positioning device has a first and second rotation axis perpendicular to the ion beam originating from the ion sourceas a rotation point for pivoting the ion beam, and the first axis of rotation is a plane of rotation of the ion beam parallel to the first direction of movement, and the second axis of rotation is a plane of rotation of the ion beam orthogonal to the first axis of rotation; wherein the control unit is configured to generate working points along a path of the point of impact of the ion beam on the substrate surface parallel to the first translational direction of movement; wherein surface parameter values ​​for each of the generated working points can be generated by means of the control unit based on a geometry of the substrate and / or a material of the substrate surface and / or a removal rate of the substrate surface and / or the steel parameter values ​​of the ion beam; wherein a first pivot angle at the point of impact can be generated for each working point along the path based on the surface parameter values ​​by means of the control unit, and theThe first swivel angle is defined by the angle between the third axis of motion and the ion beam in the plane formed by the second and third axes of motion; wherein, by means of the control unit, a second identical swivel angle of the point of entry can be generated for each of the working points along the path based on the surface parameter values, and the second swivel angle is defined by the angle between the third axis of motion and the ion beam in the plane formed by the first and third The plane formed by the axis of motion is defined; and wherein the control signal, based on the surface parameters generated by the path defined by the generated operating points, and the generated first and second swivel angles for positioning the point of impact of the ion beam relative to the substrate surface, can be generated by the positioning device in the first, second, and third translational axis of motion as well as around the first and second rotational axes, and can be transmitted from the control unit to the positioning device, so that precise ion beam etching is carried out by the five-axis positioning device, in particular the point of impact of the ion beam on the substrate surface is very precise and at a predefined angle at the point of impact, so that the ablation is very precise.Furthermore, the two delivery axes are less complex to design, as they do not need to be as mechanically stable and capable of high acceleration, unlike the positioning axes. In one embodiment, the surface parameters allow for the detection of a target thickness and / or actual thickness and / or residence time and / or a corresponding spherical point and / or a pulse rate of the ion beam and / or a material thickness to be removed at each operating point, so that the control signal generated by the control device for controlling the positioning device and the ion source ensures precise positioning of the ion beam at the point of impact on the substrate surface and precise control of the ion source for precise removal of the material thickness at the point of impact. In a further embodiment, the residence time at each operating point can be generated by the control unit based on the target thickness and the actual thickness at the respective operating point, as well as the ablation rate of the substrate surface and / or the beam parameter values ​​of the ion beam. This allows the ion beam to be positioned along the path with a constant power and diameter, thereby ensuring a stable ablation rate at the point of impact. The ablated material thickness can then be controlled by the residence time of the ion beam at the point of impact. In a further embodiment, the control unit is configured to generate a velocity profile of the ion beam along the path based on the residence times and the distances between the operating points. This generates the ion beam. As a result, the ion beam is not positioned at the point of impact for a generated dwell time, but rather guided along the path at a varying speed according to the velocity profile, thereby achieving a uniform removal of material along the path on the substrate surface. In one embodiment, the ion source comprises an ion beam generator for generating the ion beam and an ion beam control system, wherein the ion beam control system, based on the control signal received by the control unit, controls a beam current to regulate the penetration depth of the ion beam into the substrate surface at the point of impact and / or an acceleration voltage to regulate a diameter of the ion beam. It should be noted at this point that the present invention relates not only to the apparatus according to the invention but also to a method for realizing the apparatus according to the invention. Brief description of the characters The following describes various embodiments of the present invention by way of examples. These examples are illustrated by the following accompanying figures: Figure 1 illustrates by way of example a schematic representation of a top view of an ion beam processing system according to an embodiment of the invention. Figure 2 illustrates an example of a substrate with several paths running parallel along a substrate surface with a positionable ion source. Figure 3 schematically shows several arrangements of the parallel paths on the substrate surface. Figure 4 shows an exemplary ablation profile of an ion beam. Figure 5 schematically shows the substrate surface in a substrate plane with the paths. Figure 6 schematically shows the positioned ion source with a schematically represented positioning device and the substrate surface in a plane orthogonal to the substrate plane. Figure 7 schematically shows the positioned ion source with a projection of the ion beam in a plane formed by the first and third axes of motion. Figure 8 shows a velocity profile in the substrate plane. Figure 9 schematically illustrates a control unit of the ion beam processing system according to the invention. Detailed description of the invention Figure 1 shows an embodiment of an ion beam processing system 1 according to the invention for ion etching a substrate surface 21 of a substrate 2, comprising an ion source 11 for generating an ion beam 111 for removing surface atoms and / or impurities from the substrate surface 21 by contact with the ion beam 111. Furthermore, the ion beam processing system 1 includes a positioning device 13 for positioning the ion beam 111 relative to the substrate surface 21 for ion etching at an impact point 211 of the ion beam 141 on the substrate surface 21, and a control unit 14 for generating a control signal 141 that can be transmitted to the ion source 11 and the positioning device 13 for controlling the positioning device 13 and regulating the ion source 11. The ion beam device also includes 1 a substrate holder 12 for releasably fixing the substrate 2 in a substrate plane. The setup illustrated in Figure 1 is arranged in a vacuum. In other words, the surface 21 of the substrate 2 is processed by means of the ion beam 14 in a vacuum. Furthermore, the positioning device 13 has a five-axis axis system 3 with a first, second and third translational axis of motion 31 , 31 1 , 312, 313 for positioning the ion beam 1 1 1 relative to the substrate surface 21, wherein the first and second translational axis of motion 31 1 , 312 are orthogonal to each other and lie in a plane parallel to the substrate plane, and wherein the third translational axis of motion 313 runs orthogonal to the substrate plane, wherein the positioning device 13 also includes a first and second axis of rotation 32, 321 , 322 perpendicular to the ion beam 1 1 1 originating from the ion source 1 1 as a rotation point for pivoting the ion beam 1 1 1. The first axis of rotation 321 runs in a plane of rotation of the ion beam 1 1 1 parallel to the first direction of motion 31 1 and the second axis of rotation 322 runs in a plane of rotation of the ion beam 1 1 1 orthogonal to the first axis of rotation 321 . The substrate holder 12 has a flat stop surface 121 as a stop for the substrate 2 and for supporting the substrate surface 21 to be processed opposite the substrate surface, which defines the substrate plane, so that the substrate 2 in the ion beam processing system 1 can be fixed in a predefined position relative to the ion beam 1 by the substrate holder 12, in particular the stop surface 121, as illustrated in Figure 6. As shown in Figure 1, the first translational axis 311 is mounted on a base plate 131 of the positioning device 13. One to four parallel linear motors, controllable by the control signal 141, can be provided for movement along the first axis of motion 311. The second translational axis 312 runs perpendicular to the first axis of motion 312. One or more parallel linear motors, controllable by the control signal 141, can be provided for movement along the second translational axis of motion 312. The third translational axis of motion 313 runs perpendicular to both the first and second axis of motion. In the exemplary embodiment, a pivotable element is located on the third axis of motion 313, thereby realizing the rotational axis 321, which forms the fourth axis. The first rotational axis 321 runs parallel to the first axis of motion 311.For pivoting about the first rotational axis 321, one or two rotary motors controllable by the control signal 141 can be provided. The second rotational axis 322, which is the fifth, is located on the first rotational axis 321. The second axis of rotation 322 runs perpendicular to the first axis of rotation 321 and perpendicular to the first axis of movement 31. One or two rotary motors, controllable by the control signal 141, can be arranged to pivot about the second axis of rotation 322. As can be seen in particular from Figure 1, the first rotation axis 321 and the second rotation axis 323 and the ion beam 1 1 1 in the ion source 1 1 intersect at a point of intersection. The ion beam source 1 1 is rigidly coupled to the second axis of rotation 322, wherein the ion beam 1 1 1 is aligned by the positioning device 13 such that the ion beam 1 1 1 forms a fixed angle of incidence to the substrate surface 21 at the point of incidence 21 1. In the exemplary embodiment, the ion beam 1 1 1 strikes the substrate surface 21 orthogonally at the point of incidence 21 1. A first angle of incidence, defined by the angle between the third axis 313 and the ion beam 1 1 1 in the plane formed by the second and third axes of motion 312, 313, is adjustable by the first axis of rotation 321, and a second angle of incidence, defined by the angle between the third axis 313 and the ion beam 1 1 1 in the plane formed by the first and third axes of motion 31 1 , 313, is adjustable by the second axis of rotation 321. The processing of substrates 2 with ion beams 1 1 1 should be carried out at the point of impact 21 1 at an orthogonal (90°) angle to the substrate surface 21 to ensure a uniform etching rate and maximum material removal, since oblique angles of impact lead to directional dependence of the processing and cause uneven surface development. The orthogonal orientation minimizes variations in the removal rate generated by the ion beam 1 1 1 at the point of impact 21 1, which arise at oblique angles due to the cosine effect, and enables precise correction of surface defects in the nanometer range without causing new damage. The control unit 14 is for generating operating points 51 1..51 i along a path 5 parallel to the first translational direction of movement 31 1, [501 ,.50i] of the point of appearance 21 1 of the ion beam 1 1 1 on the substrate surface 21 trained. Whereby, by means of the control unit 14, surface parameter values ​​41 can be generated for each of the generated operating points 51 1 ..51 i, which are based on a geometry of the substrate 2 and / or a material of the substrate surface 21 and / or a removal rate of the substrate surface 21 and / or removal parameter values ​​of the ion beam 1 1 1. By means of the control unit 14, a first swivel angle 321 1 at the point of entry 21 1 can be generated for each operating point 51 1 ..51 i along the path 5, [501..50i] based on the surface parameter values ​​41, wherein the first swivel angle 321 1 is defined by the angle between the third axis of motion 313 and the ion beam 1 1 1 in the plane formed by the second and third axes of motion 321 , 323. Furthermore, by means of the control unit 14, a second identical swivel angle 3221 of the entry point 21 1 can be generated for each of the operating points 21 1 along the path 5, [501 ,.50i] based on the surface parameter values ​​41, wherein the second swivel angle 3221 is defined by the angle between the third axis of motion 313 and the ion beam 1 1 1 in the plane formed by the first and third axes of motion 322, 323. The control signal 141 is based on the path 5 defined by the generated operating points 21 1 and the generated surface parameters 41 and the generated first and second swivel angles 321 1 , 3221 for positioning the point of impact 21 1 of the ion beam 141 relative to the substrate surface 21 by means of the positioning device 13 in the first, second and third translational axis of movement 31 1 , 312 , 313 as well as about the first and second rotational axes 321 ,322 to the positioning device 13 and can be transmitted from the control unit 14 to the positioning device 13. The control unit 14 can receive input data and commands from various systems and components of the ion beam processing system 1 via an interface and generate the control signals 141 for controlling the components of the ion beam processing system 1 and send them to the components. The control unit 14 can be or contain a computing unit or a network of computing units that can be programmed to perform desired input / output functions. The control unit 14 can include a processor and memory. The processor The memory may comprise one or more processors known in the art. The memory may comprise one or more computer-readable media that provide program code or computer instructions for use by or in conjunction with a computer system or any command-execution system. For the purposes of this description, a computer-readable medium may be any device capable of containing, storing, communicating, distributing, or transporting the program for use by or in conjunction with the computer, command-execution system, device, or apparatus. The computer-readable medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or device or apparatus), or a transmission medium.Examples of computer-readable media include semiconductor or solid-state memory, magnetic tapes, removable storage media (floppy disks), random access memory (RAM), read-only memory (ROM), rigid magnetic disks, and optical disks. Current examples of optical disks are Compact Disc - Read Only Memory (CD-ROM), Compact Disc - Read / Write (CD-R / W), and Digital Video Disc (DVD).

[0023] The control unit 14 may also include other electronic circuits or components, such as application-specific integrated circuits, other hardwired or programmable electronic devices, discrete element circuits, etc. The control unit 14 may also include communication devices. A user interface system may include, among other things, devices such as touchscreens, keyboards, user pointing devices, displays, printers, etc., which allow a user to input commands and data and / or monitor the ion beam processing system 1 via the control unit 14. The surface parameter values ​​4, 41 are selectably stored in the memory of the control unit 14, whereby for each operating point 51 1 ..51 i a target thickness and / or an actual thickness and / or a residence time and / or a corresponding spherical point 521 ,.52i and / or a pulse rate of the ion beam 1 1 1 and / or a material thickness to be removed can be determined by the surface parameters 41 and / or. To generate the spherical points 521, 52i corresponding to the operating points 511...51i, a spherical surface 22 is generated based on the operating points 511...51i, wherein the generated spherical surface 22 has a minimal deviation from the substrate surface 2. Under a spherical surface 22 My understanding is an ideal spherical surface with radius R and a center M (xo, yo, zo), where each spherical point (x, y, z) satisfies the following equation: (x-xo) 2 + (yy o) 2 + (z-zo)2= R 2 The following applies to work points 511, 512, 513: Xi 2 +yi 2 +Zi 2 =2axi+2byi+2czi+D, where Xi, yi, Zi correspond to the coordinates of the i-th working point 51 i. A • c « f, where The solution is found using the following normal equation: c = Q4 r • ) 1 • A T f The radial deviation of each operating point 51 1 ..51 i to the corresponding spherical point 521 ,.52i corresponds to: Where (Xi, yi, Zi) represent the coordinates of the work points 51 1 ..51 i to the three axes of motion 31 , 31 1 , 312, 313. In another embodiment, there is a deviation between the spherical Surface 22 and the substrate surface 21 with a mean square The deviation (RMS) between the substrate surface 21 and the spherical surface 22 (ideal sphere surface) is quantified. In a further embodiment, based on the generated spherical surface 22 and the operating points 51 1 ..51 i, a corresponding spherical operating point 521 ,.52i is generated for each of the operating points 51 1 ..51 i, such that all operating points 51 1 ..51 i are available as corresponding spherical points 521 ,.52i with a minimal deviation from the substrate surface 21. The first identical swivel angle 321 1 at the point of impact 21 1 is generated for all operating points 51 1 ..51 i along the path 5, [501 ,.50i] based on the corresponding spherical operating points 521 ,.52i, so that the positioning of the ion beam 1 1 1 at the point of impact 21 1 on the substrate surface 21 along the path 5, 501 ,.50i with the first identical swivel angle 321 1 has only a small deviation from the fixed angle of impact, for example to the orthogonal at the point of impact 21 1 , on the substrate surface 21. To determine substrate parameter values, substrate 2 can be analyzed, for example optically. Alternatively, it is conceivable that at least some substrate data is specified, such as the basic shape of substrate 2, the presence of a coating, and / or the material of substrate 2. In the present embodiment, the aim is to achieve a defined geometry of the substrate surface 21 of the substrate 12 and / or a uniform microroughness of the substrate surface 21 by processing the substrate 2. For this purpose, target substrate parameter values ​​of the substrate surface 21 to be processed are defined, whereby the target substrate parameters capture an operating point 51 1 ,.51 i with the respective coordinates of the movement axes 31 1 , 312, 313. In a further embodiment of the invention, the target substrate parameters encompass a microroughness and / or a geometry of the substrate 2 with a target thickness for each operating point 51 1 ..51 i, a vibration behavior of a partial area on the substrate surface 21 of the substrate 2 and / or the thickness of a coating of the substrate 2. The microroughness of the target substrate parameter value is, for example, in the range of an RMS value of 0.1 nm to 10 micrometers. The target substrate parameter values ​​and substrate parameter values ​​for the substrate surface 21 of the substrate 2 can be received and sent via the control unit 14 through its interface. Furthermore, the control unit 14 is configured to record a basic shape of the substrate 2 and / or a surface geometry, each with an actual thickness for each operating point, a substrate material, a material removal rate of the substrate 2, and other parameters dependent on the substrate geometry, such as the reflectivity or scattering behavior of the substrate surface 21, the vibration behavior of the substrate 2, the presence of a coating, and the thickness of a coating, in the memory of the control unit 14. Using the control unit 14, the material thickness to be removed at the corresponding operating point 51 1 ..51 i can be generated based on the target thickness and the actual thickness at the respective operating point 51 1 ..51 i. Furthermore, using the control unit 14, a velocity profile, as illustrated in Figure 7, can be generated based on the surface parameter values ​​41 for moving the ion steel 141 in a direction of movement 51 on the substrate surface 21 by means of the positioning device along the path 5, [501 ...50i]. The ion source 14 comprises an ion beam generator for generating the ion beam 141 and an ion beam control, wherein the ion beam control, based on the control signal 141 receivable by the control unit 14, provides an acceleration voltage for controlling the ion energy to control the penetration depth into the substrate surface 21 and / or an acceleration voltage for controlling a diameter of the ion beam 141. In one embodiment of the present invention, the control unit 14 generates several parallel paths 5, [501 ... 50i] on the substrate surface 21, wherein adjacent loose ends are each connected by a connecting path. The entirety of the paths 5, 501, 50i and the connecting paths form a process path, as is shown in particular in Figure 3. The corresponding travel path ensures that all areas to be processed on the substrate surface 21 are accessed. Among other things, the residence time defines how much material is to be removed at a specific operating point 51 1 ..51 i. The higher the desired material removal, the longer the residence time can be, especially if the intensity of the ion beam 1 1 1 generated by the ion beam source 1 1 remains constant. Since the desired material removal usually varies across the substrate surface 21, the residence time can also vary. When processing the substrate surface 21 of the substrate 2, material removal typically occurs in the range of up to 10 m, in particular material removal of up to 1 pm. The surface profile 41 can be created before or during the ion beam etching of the substrate surface 21. The control unit 14 simultaneously controls the three axes of the positioning device 13 by means of the control signal 141 to move the ion beam 111 along the travel path 22 with a residence time or ion beam velocity corresponding to the surface profile 41 and the generated first and second swivel angles, and to remove material at the point of impact 211 with the ion beam 111. The velocity of the ion beam 111 for the working points 5111...51i can be generated by the control unit 14 based on the respective working point 5111...51i and at least one working point 5111...51i adjacent to the respective working point 5111...51i, as well as their residence time and distance. The angle of incidence of the ion beam 1 1 1 relative to the substrate surface 21 of the substrate 2 remains constant during a processing operation. The remaining two axes of the five-axis positioning device 13, in the exemplary embodiment the first translational axis of motion 311 and the second rotational axis 322, are controlled by the control unit 14 solely for moving the ion beam source 11 from one path 5, 501, 0.50i to an adjacent path 5, 501, 0.50i of the process path. During this movement via the moving axes, however, no material removal by the ion beam 111 takes place. In this respect, the delivery axes differ from the axes 31, 311, 312, 313, 321, 322 controlled in simultaneous operation, among other things, in that no ion beam 11 1 is present during a movement along at least one of the delivery axes, since only a delivery is taking place. Looking at the process path 54 shown in Figure 3, it is evident that the meandering travel path 54 begins at a starting point 55, has the parallel paths 5, 501, 50i, and connecting sections 53. The connecting sections 53 are also referred to as turning points. In the illustrated embodiment, the parallel paths 5, 501, 50i run on small circles of a spherical surface. While the ion beam source 11 is moved along the paths 5, 501, 50i, the processing of the substrate surface, in particular the ion etching, takes place. During the movement along these paths 5, 501, 50i, the control unit 14 simultaneously controls the three aforementioned axes of motion 312, 313, 321 of the positioning device 13. Furthermore, the ion beam source 11 is controlled by the control unit 14 by means of the control signal 141 so that the ion beam 111 is generated by the ion beam source 11, as will be explained in more detail below. By means of the process along the connecting sections 53, the ion beam source 1 1 1 is moved from one path 5, 501, .50i to the next path 5, 501, .50i. During the process along the connecting sections 53, the control unit 14 controls the two feed axes 31 1, 322 by means of the control signal 141. No processing takes place during the process along the connecting sections 53, as previously explained. It is also conceivable that the connecting sections 53 lie outside the substrate 2, in particular the substrate surface 21, as illustrated in Figure 3 for some process paths. In this case, the ion beam 1 1 1 does not need to be switched off during the process along the connecting sections 53. Whether a connecting section 53 lies on a substrate 2 or outside the substrate 2 depends on the type of substrate 2 and the position of the area to be processed, in particular on whether the entire substrate surface 21 of the substrate 2 is to be processed or only parts of it. However, depending on the application, it is not necessarily required to treat the entire substrate surface 21 of the substrate 12. It is also conceivable that only local areas of the substrate 2, more precisely individual circular areas on the substrate surface 21 of the substrate 2, are treated. These local areas can, in principle, have any shape. They can be circular, elliptical, rectangular, linear, or point-like. In particular, the partial areas are contiguous. In addition to the travel distance 54, the dwell time and the swivel angle 321 , 322 of the ion beam 1 1 1, the surface profile 41 can also detect further parameters 4, 42 relating to the ion beam 1 1 1. For example, the control unit 14 can control the ion beam 1 1 1 in such a way that the ion beam 1 1 1 pulses during processing in order to control the energy input or the material removal at the point of impact 21 1 of the ion beam 1 1 1 on the substrate surface 21. Furthermore, the control unit 14 can control the ion beam 1 1 1 in such a way that the cross-section of the ion beam 1 1 1 at the point of impact 21 1 on the substrate surface 21 is changed during a processing operation. The ion beam 1 1 1 is therefore focused, which means that the area being processed simultaneously at the point of impact 21 1 on the substrate surface 21, i.e., the area under irradiation, is variable. The cross-section of the ion beam 1 1 1 can be elliptical or circular. The intensity of the ion beam 1 1 1 can remain constant on average during a processing operation, especially if a different material removal is controlled via the residence time or the speed of the ion beam 1 1 1 relative to the substrate surface 21. Alternatively, the intensity of the ion beam 1 1 1 can also be varied on average during a processing operation, which can, for example, reduce dwell times. This allows for temporal process optimization. Figure 4 illustrates a material removal profile of the ion beam 1 1 1. The material removal profile defines how the ion beam 1 1 1 removes material from the substrate surface 21 of the substrate 2 during processing. The ablation profile of the ion beam 1 1 1 can be recorded as part of a calibration process before processing the substrate 2. This process is usually repeated at regular intervals, as the ablation profile can change over the lifetime of the ion beam source 1 1. The machining profile is created by the control unit 14, taking the material removal profile into account. In another embodiment, the operating points 51 1..5H are generated by a measuring device by measuring the operating points 51 1..5H on the substrate surface 21 of the substrate 2 and received via the interface of the control unit 14 and stored in the memory of the control unit 14 in a selectable manner. In a further embodiment, the ion beam machining system 1 includes the measuring device for measuring the substrate surface 21. Suitable optical measuring devices include, for example, an interferometer. Reference list 1 ion beam processing system 1 ion beam source 1 1 1 lon beam 12 Substrate holder 121 Stop surface 13 Positioning device 131 Base plate 14 Control unit 141 Control signal 2 Substrat 21 substrate surface to be processed 21 1 Performance Point 22 Spherical surface 3-axis system 31 translational axes of movement 31 1 first translational axis of motion / x-axis 312 second translational axis of motion / y-axis 313 third translational axis of motion / z-axis 32 axes of rotation 321 first axis of rotation 321 1 first swivel angle 322 second axis of rotation 3221 second swivel angle 4 parameters 41 surface parameters 42 beam parameters 5 paths 501..501 multiple paths 51 1 ..511 work points on the path 521 ..521 Spherical Points 53 Connecting section 54 Procedure 55 Starting point of a path

Claims

24 Claims 1. Control method for ion etching a substrate surface (21) of a substrate (2) with an ion source (11), wherein surface atoms and / or impurities on the substrate surface (21) are removed by contact with an ion beam (111) of the ion source (11) when the substrate surface (21) is exposed to the ion beam (111), wherein an impact point (211) of the ion beam (111) for ion etching is positioned relative to the substrate surface (21) by a positioning device (13), and wherein the positioning device (13) and the ion beam (111) are controlled by a control signal (141) generated by a control unit (14) and transmitted to the positioning device (13) and the ion source (11), characterized by, Fixing the substrate (2) to a substrate holder (12) in a substrate plane (31), wherein the ion beam (111) is positioned relative to the substrate surface (21) along a first, second, and third translational axis of motion (311, 312, 313) by means of the positioning device (13), wherein the first and second translational axis of motion (311, 312) are orthogonal to each other and lie in a plane parallel to the substrate plane, and wherein the third translational axis of motion (313) is orthogonal to the substrate plane, and wherein the ion beam (111) is pivotable about a first and second axis of rotation (321, 322) perpendicular to the ion beam (111) originating from the ion source (11) as a point of rotation, wherein the first axis of rotation (321) is a plane of rotation of the ion beam (111) parallel to the first direction of motion (311), and the second axis of rotation (322) is a The plane of rotation of the ion beam (111) is orthogonal to the first axis of rotation (321); Generating operating points (511..51 i) along a path (5, [501..50i]) parallel to the second translational direction of motion (312) of the point of appearance (211) of the ion beam (111) on the substrate surface (21); Generating surface parameter values ​​(41) for each of the generated operating points (511..51 i) based on a geometry of the substrate (2) and / or a material of the substrate surface (21) and / or a removal rate of the substrate surface (21) and / or beam parameter values ​​(42) of the ion beam (111); Generating a first swivel angle (321 1 ) at the entry point (21 1 ) for each of the working points (51 1 ..51 i) along the path (5, [501 ,.50i] ) based on the generated surface parameters (41), wherein the first swivel angle (321 1) is defined by the angle between the third axis of motion (313) and the ion beam (1 1 1 ) in the plane formed by the second and third axes of motion (312, 313); Generating a second identical swivel angle (3221) at the entry point (211) for all operating points (211) along the path (5, [501, 50ij]) based on the generated surface parameter (41), wherein the second swivel angle (3221) is defined by the angle between the third axis of motion (313) and the ion beam (111) in the plane formed by the first and third axes of motion (311, 313); ion beam etching along the path (5, [501..50i]), wherein the control signal (141) is based on the path (5, 511..51i) defined by the generated operating points (511..51i).51 i) and the generated surface parameters (41 ) and the generated first and second swivel angles (321 1 , 3221 ) are generated, and wherein the positioning of the point of impact (21 1 ) of the ion beam (141 ) relative to the substrate surface (21 ) is controlled by means of the positioning device (13) in the first, second and third translational axis of motion (31 1 , 312, 313) as well as about the first and second rotational axes (321 ,322) by means of the control signal (141 ) transmitted to the positioning device (13).

2. Control method for ion etching of a substrate surface (21 ) of a substrate (2) with an ion source (1 1 ), according to one of claims 1 , characterized by generating a spherical surface (22) based on the operating points (51 1 ..51 i ), wherein the generated spherical surface (22) has a minimal deviation from the substrate surface (2 ), Generating a spherical work point (521..52i) corresponding to each of the work points (51 1 ..51 i) based on the generated spherical surface (22) and the work points (51 1 ..51 i), and Generating the second identical swivel angle (3221 ) at the entry point (21 1 ) for all working points (51 1 ..51 i) along the path (5, [501 ,.50ij) based on the corresponding spherical working points (521..52i) .

3. Control method for ion etching of a substrate surface (21 ) of a substrate (2) with an ion source (1 1 ), according to claim 2, characterized by generating the spherical operating points ) 521 ,.52i) by the intersection of the spherical surface (22) with the straight line passing through the respective operating point (51 1 ..51 i) orthogonally to the substrate surface (21 ) at the operating point )51 1 ..51 i).

4. Control method for ion etching of a substrate surface (21 ) of a substrate (2) with an ion source (1 1 ), according to claims 1 to 3, characterized by generating a residence time of the ion beam (1 1 1 ) for each operating point (51 1 ..51 i) based on a target thickness and an actual thickness at the respective operating point (51 1 ..51 i) as well as the removal rate of the substrate surface (21 ) and / or the beam parameter values ​​(42) of the ion beam (1 1 1 ) .

5. Control method for ion etching of a substrate surface (21 ) of a substrate (2) with an ion source (1 1 ), according to one of claims 1 to 4, characterized by measuring an alignment position of at least two marking points arranged on the substrate surface (21 ) relative to the ion beam (1 1 1 ) based on the axes of movement (31 1 , 312, 313) .

6. Control method for ion etching of a substrate surface (21 ) of a substrate (2) with an ion source (1 1 ), according to one of claims 1 to 5, characterized by generating operating points (51 1 ..51 i) along several paths (5, [501..50i]) parallel to the second translational direction of movement (31 1 ) of the point of appearance (21 1 ) of the ion beam (1 1 1 ) on the substrate surface (21 ), wherein the parallel paths (5, [501..50i]) are connected by connecting sections (53), such that a meandering process path (54) is formed by the paths (5, [501..50i]) and the connecting sections (53).

7. Control method for ion etching of a substrate surface (21 ) of a substrate (2) with an ion source (1 1 ), according to one of claims 1 to 6, 27 characterized by generating the control signal (141 ) based on the path (5, 51 1 ..51 i) defined by the generated operating points (51 1 ..51 i) and the generated surface parameters (41 ), wherein the beam parameter values ​​(42) are controlled by means of an ion beam control of the ion beam source (14) by means of the control signal (141 ) transmitted to the ion source (14).

8. Ion beam processing system (1) for ion etching a substrate surface (21) of a substrate (2) comprising an ion source (11) for generating an ion beam (111) for removing surface atoms and / or impurities from the substrate surface (21) by contact with the ion beam (111), a positioning device (13) for positioning the ion beam (111) relative to the substrate surface (21) for ion etching at an impact point (211) of the ion beam (141) on the substrate surface (21), and a control unit (14) for generating a control signal (141) transmittable to the ion source (14) and the positioning device (13) for controlling the positioning device (13) and regulating the ion source (11), characterized in that The ion beam processing system (1) has a substrate holder (12) for fixing the substrate (2) in a substrate plane (31), wherein the positioning device (13) has a first,second and third translational axes of movement (31 1 , 312, 313) for positioning the ion beam (1 1 1 ) relative to the substrate surface (21 ), wherein the first and second translational axes of movement (31 1 , 312) are orthogonal to each other and lie in a plane parallel to the substrate plane (31 ), and wherein the third translational axis of movement (313) is orthogonal to the substrate plane, wherein the positioning device (13) has a first and second rotation axis (321 ,322) vertically to the ion beam (1 1 1 ) starting from the ion source (1 1 ) as a rotation point for pivoting the ion beam (1 1 1 ) and the first rotation axis (321 ) a rotation plane of the ion beam (1 1 1 ) parallel to the first direction of movement (31 1 ) and the second rotation axis (322) a rotation plane of the ion beam (1 1 1 ) orthogonal to the first rotation axis (321 ); wherein the control unit (14) for generating operating points (51 1..5Ü) along a parallel to the second translational direction of movement (312), 28 path (5, [501 ,.50i] ) of the point of impact (51 1 ..51 i) of the ion beam (1 1 1 ) on the substrate surface (21 ) is formed; wherein surface parameter values ​​(41 ) for each of the generated working points (21 1 ) can be generated by means of the control unit (14) based on a geometry of the substrate (2) and / or a material of the substrate surface (21 ) and / or a removal rate of the substrate surface (21 ) and / or the steel parameter values ​​(42) of the ion beam (1 1 1 ) ; wherein a first swivel angle (321 1 ) at the point of impact (51 1 ..51 i) for each working point (51 1 ..51 i) along the path (5, [501..50i]) based on the surface parameter values ​​(41) and the first swivel angle (321 1) is defined by the angle between the third axis of motion (313) and the ion beam (1 1 1) in the plane formed by the second and third axes of motion (312, 313); wherein, by means of the control unit (14), a second identical swivel angle (3221) of the point of entry (21 1) can be generated for each of the operating points (21 1) along the path (5) based on the surface parameter values ​​(41) and the second swivel angle (3221) is defined by the angle between the third axis of motion (313) and the ion beam (1 1 1) in the plane formed by the first and third axes of motion (31 1, 313); and wherein the control signal (141) is based on the operating points (51 1 ..) generated by the51 i) defined path (5) generated surface parameters (41 ), and the generated first and second swivel angles (321 1 , 3221 ) for positioning the point of impact (21 1 ) of the ion beam (141 ) relative to the substrate surface (21 ) by means of the positioning device (13) in the first, second and third translational axis of motion (31 1 , 312, 313) as well as about the first and second rotational axes (321 ,322) to the positioning device (13) can be generated and transferred from the control unit (14) to the positioning device (13).

9. Ion beam processing system (1) for ion etching a substrate surface (21) of a substrate (2), according to claim 8, characterized in that the surface parameters (41) define a target value for each operating point (51 1 "51 i) 19 Thickness and / or an actual thickness and / or a residence time and / or a corresponding spherical point (521 ,.52i) and / or a pulse rate of the ion beam (1 1 1 ) and / or a material thickness to be removed can be detected.

10. Ion beam processing system (1 ) for ion etching a substrate surface (21 ) of a substrate (2), according to claims 8 to 9, characterized in that for each of the operating points (51 1 ..51 i] based on the target thickness and the actual thickness at the respective operating point (51 1 ..51 i) as well as the ablation rate of the substrate surface (21 ) and / or the beam parameter values ​​(42) of the ion beam (1 1 1 ) the residence time at the operating point (51 1 ,.51 i) can be generated by the control unit (14).

11. Ion beam processing system (1 ) for ion etching a substrate surface (21 ) of a substrate (2), according to claims 8 to 10, characterized in that the ion source (14) comprises an ion beam generator for generating the ion beam (141 ) and an ion beam control, wherein the ion beam control, based on the control signal (141 ) receivable by the control unit (14) , controls a beam current to control the penetration depth of the ion beam (1 1 1 ) into the substrate surface (21 ) at the point of appearance (21 1 ) and / or an acceleration voltage to control a diameter of the ion beam (141 ).

12. Ion beam processing system (1 ) for ion etching a substrate surface (21 ) of a substrate (2), according to claims 8 to 1 1 , characterized in that a velocity profile for positioning the ion beam (141 ) by means of the control unit (14) based on the surface parameter values ​​(41 ) can be generated.

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