Vibration isolation system with magnetic actuator and magnetic actuator

Abstract

An active vibration isolation system includes a magnetic actuator. The magnetic actuator includes a coil carrier with at least one coil, which is engaged in the magnet carrier without contact, thereby forming the magnetic actuator in the form of a linear motor. The magnetic actuator includes a magnetic shield. The magnetic shield includes an opening through which the coil carrier extends into the magnet carrier.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to a vibration isolation system with a magnetic actuator, and in particular to a stationary vibration isolation system on which magnetically sensitive equipment, such as semiconductor processing equipment or high precision measurement tools such as electron microscopes, is positioned.

[0002] The present invention further relates to a magnetic actuator for a vibration isolation system.

[0003] Background of the Invention Active vibration isolation systems are known from practice, particularly in the semiconductor industry, where vibration isolation systems are used in which equipment for processing semiconductor elements, such as equipment for exposing or inspecting wafers, is supported on at least three vibration isolators.

[0004] Vibration isolation systems are also used for high-precision measuring instruments, such as electron microscopes or transmission electron microscopes ("TEM"), on which the instruments are positioned. Transmission electron microscopes enable direct imaging of objects with electron radiation. The operation of such microscopes places particularly high demands on the one hand with regard to possible vibrations to which the system is exposed, and on the other hand with regard to possible interfering magnetic fields.

[0005] The active vibration isolation system includes a sensor in the vibration-isolated, supported load and / or the floor, and vibrations are detected via the sensor. Based on the detected vibrations, an actuator is controlled by a controller. The actuator acts on the vibration-isolated, supported load to generate a reaction force to reduce vibrations in the vibration-isolated, supported load.

[0006] As actuators, in particular magnetic actuators are used, which are constructed according to the principle of linear motors and have the advantage that they generate relatively large forces over a wide frequency range in a small construction space.

[0007] However, a disadvantage of known magnetic actuators is the magnetic field generated by the permanent magnets and / or coils.

[0008] The magnetic field interferes with magnetically sensitive instruments such as scanning electron microscopes or transmission electron microscopes and is therefore often not possible to incorporate in the vicinity of the instruments.

[0009] This means that magnetically sensitive equipment, such as equipment for processing semiconductor elements or high-precision measuring instruments such as electron microscopes or especially transmission electron microscopes, cannot be operated in conjunction with stationary vibration isolation systems that are actuated by magnetic actuators, because the magnetic fields of the magnetic actuators would affect or even corrupt the measurement results.

[0010] This results in another drawback in that such high-precision measuring instruments often cannot be operated in the immediate vicinity of production facilities or other equipment that generates floor vibrations, since the above-mentioned stationary vibration isolation systems with magnetic actuators cannot be used based on interference caused by magnetic fields.

[0011] The inventors of the present application have made efforts to achieve this goal.

[0012] Problems to be Solved by the Invention In contrast, the object underlying the present invention is to at least reduce the above-mentioned disadvantages of the prior art.

[0013] In particular, the object of the present invention is to provide a stationary vibration isolation system with a magnetic actuator that can be used in connection with equipment for processing semiconductor elements or high-precision measuring instruments such as electron microscopes, or in particular transmission electron microscopes.

[0014] Therefore, the present invention desirably enables such equipment and tools to be operated in the vicinity of manufacturing facilities or other equipment that generates floor vibrations, without the operation of such equipment or tools being impaired by, for example, the magnetic fields of a vibration isolation system.

[0015] Summary of the Invention The object of the present invention is already achieved by a vibration isolation system and a magnetic actuator for a vibration isolation system according to one of the independent claims.

[0016] Preferred embodiments and refinements of the invention emerge from the subject matter of the dependent claims, the description and the drawings.

[0017] The present invention relates to a vibration isolation system including a vibration-isolated and supported load part, the vibration isolation system having at least one magnetic actuator controlled via a controller.

[0018] The invention particularly relates to a stationary vibration isolation system in which a plate is vibrationally isolated and supported on at least three vibration isolators, the vibration isolation system serving in particular to accommodate equipment for processing semiconductor elements, such as for example lithography equipment or wafer inspection equipment, and / or to accommodate high-precision measuring tools, such as electron microscopes, or in particular transmission electron microscopes.

[0019] Therefore, in another aspect, the present invention includes a high-precision measuring instrument or a high-precision imaging optical device, in particular a microscope, electron microscope or transmission electron microscope, which includes a vibration isolation system with at least three vibration isolators, preferably at least one vibration isolator including a magnetic actuator, and particularly preferably each of a plurality of vibration isolators including a magnetic actuator.

[0020] The vibration isolation system according to the present invention is therefore suitable for use in connection with an electron energy loss spectroscopy ("EELS" = Electron Energy Loss Spectroscopy) instrument or electron energy loss spectroscopy.

[0021] Such methods allow, for example, the stoichiometric and electronic characterization of inorganic or organic structures. Electron energy loss spectroscopy, often performed using a transmission electron microscope, first determines the energy loss spectrum of monoenergetic or monochromatic electrons upon interaction with a sample.

[0022] The concept of "monoenergetic" is understood to mean that the width of the energy distribution of the primary electrons is as small as possible relative to the width of the measured spectrum, since the width of the distribution presupposes the achievable spectral resolution of the method. The primary electrons interact with the charged particles of the sample (protons and electrons bound to neutrons in atomic nuclei) via their electric field. Since atomic nuclei have a much larger mass than individual electrons, the energy transfer from the primary electrons to the atomic nuclei is rather negligible. In contrast, when interacting with solid-state electrons, significant energy losses occur, which can be determined based on the characteristic probability distribution of the energy transfer.

[0023] In this case, it is important that there is as little or as little magnetic field interference as possible in the area of ​​the sample to be measured, and in particular that no magnetic field interference is formed by vibration insulators, so that high-precision measurements can be carried out without the superposition of such magnetic fields.

[0024] This region, which accommodates the sample during the measurement, is also referred to below as the measurement region. On the other hand, additional magnetic fields penetrating into the measurement region would deflect the primary electrons and thus corrupt the measurement results.

[0025] In one preferred embodiment, the measurement area of ​​the imaging optics is located as far away as possible from the vibration isolator, in particular from the at least one magnetic actuator, since this distance already allows a certain degree of damping of the magnetic field of the magnetic actuator.

[0026] For example, in an arrangement with three spaced apart vibration isolators, in particular with magnetic actuators, the measurement area can be particularly advantageously located in the area of ​​the circumscribed circle center point of the triangle formed by the three vibration isolators.

[0027] For example, in an arrangement with four spaced apart vibration isolators, in particular with magnetic actuators, the measurement area can be particularly advantageously located in the area of ​​the center point of the rectangle or square formed by the four vibration isolators.

[0028] Generally, it is advantageous if the measurement area has the same distance from all vibration isolators of the vibration isolation system, at least from the vibration isolator that includes the magnetic actuator. The measurement area can be understood, for example, as a spatial area that is usually in the form of a hexahedron or a rectangular parallelepiped and has a receptacle for the sample. The sample to be measured is positioned at least partially in this area, so that the measurement can be performed. When referring to the distance of the measurement area, this is understood to be the distance from the center of gravity of this spatial area, i.e., the center of gravity of a hexahedron, for example, or the distance from the center point of the receptacle for the sample.

[0029] The magnetic actuator acts on a vibration-isolated supported load part and generates a reaction force to reduce vibration in at least one spatial direction.

[0030] The magnetic actuator is particularly configured as a linear motor and comprises a coil carrier with at least one coil arranged in a U-shaped magnet carrier. This basic configuration of the magnetic actuator according to the invention makes it particularly advantageous to optimize the components in order to enable extremely high shielding, which is required in order to be able to carry out measurements without interfering magnetic fields.

[0031] In accordance with the present invention, the magnetic actuator includes a magnetic shield.

[0032] Therefore, the present invention provides for providing the magnetic actuator with a housing that acts as a magnetic shield.

[0033] The magnetic shield is made, in particular, of a soft metal.

[0034] By means of the magnetic shield, the magnetic field present or occurring inside the magnet actuator is deflected and bundled, so that the magnetic field is significantly weakened on the outside.

[0035] The magnetic shield has in particular a magnetic permeability μ greater than 1000, preferably greater than 10,000, particularly preferably greater than 50,000. r The material has a

[0036] In particular, the magnetic shield is made of mu-metal, a soft magnetic iron-nickel alloy with a magnetic permeability μ of typically 80,000 to 500,000. r It has the following characteristics.

[0037] The magnetic shield is formed as a casing with an opening in one wall, from which opening preferably the arm of the magnetic actuator, in particular the coil carrier, projects.

[0038] The opening is preferably dimensioned so that the coil carrier extends contactlessly into the magnet carrier, but the gap extending around the periphery of the coil carrier is kept as small as possible, in particular having a maximum width of less than 2 mm, preferably less than 1 mm.

[0039] The magnetic shield may be provided as a rectangularly formed casing with specially constructed walls, so that no permeability-decreasing deformations of the material need be carried out during the manufacture of the casing.

[0040] In another embodiment, the magnetic actuator includes a winding with a magnetic shield, which may in particular be made up of several layers, so that deformations that weaken the magnetic permeability remain small despite the presence of the winding.

[0041] It has been shown that extremely thin windings of mu metal, in particular multi-layer windings with a total thickness of less than 1 mm, preferably less than 0.5 mm, result in a significant reduction in the magnetic field generated by the magnetic actuator.

[0042] The magnetic shield may in particular have a thickness of 0.1 mm to 10 mm, preferably 0.2 mm to 1 mm.

[0043] According to one embodiment of the invention, the magnetic actuator is integrated into a vibration isolator, which includes a spring and serves to provide vibration-isolated support for the load part to be isolated.

[0044] The spring can be configured, for example, as a pneumatic spring, and the magnetic actuator according to the invention can be arranged in an insulator, for example in the working chamber of the pneumatic spring or in the housing of the pneumatic spring.

[0045] The present invention allows the magnetic actuator to be mounted in the vicinity of equipment for processing semiconductor devices. In particular, the magnetic actuator according to the present invention may be positioned at a distance of less than 50 cm from equipment for processing semiconductor devices, such as a scanning electron microscope.

[0046] Particularly advantageously, the magnetic actuator according to the invention enables, based on the shield, to be operated in or in connection with high-precision imaging optics, in particular microscopes, electron microscopes, transmission electron microscopes.

[0047] Thus, a high-precision imaging optical device can be provided with an arrangement of multiple vibration isolators, in particular magnetic actuators, in which, during operation, the magnetic field is less than 15 nT, preferably less than 10 nT, particularly preferably less than 9 nT, at a distance of less than 70 cm, less than 50 cm, preferably less than 45 cm, and particularly preferably less than 40 cm from at least one vibration isolator, in particular magnetic actuator.

[0048] This high degree of shielding can on the one hand provide an arrangement with more than three vibration isolators, in particular magnetic actuators, preferably with four or more vibration isolators. Such an arrangement of vibration isolators, in particular four magnetic actuators instead of three, allows for a significantly more stable configuration of the imaging optical device, and for example allows for better prevention of unintentional tipping of the device.

[0049] The shielding also makes it possible to operate the imaging optics in working environments or at times where vibrations are a consideration. The above-mentioned low magnetic fields in the measurement area could be achieved, for example, due to a vibration isolation system in a test environment with a total floor amplitude of 20 μm and 0.5 Hz.

[0050] The high degree of shielding of the magnetic actuator, on the other hand, allows for a relatively small construction, since the magnetic actuator can be arranged relatively close to the measurement area, and therefore the vibration isolation system and thus the imaging optics can be kept very compact.

[0051] In another preferred embodiment, the vibration isolation system includes at least two magnet actuators for generating compensation signals (compensation forces) in at least two spatial directions that are different from each other.

[0052] The invention further relates to a vibration isolation system, in particular a magnetic actuator for the vibration isolation system described above.

[0053] The magnetic actuator includes a magnet carrier with opposing magnets.

[0054] In particular, the magnet carrier is formed in a U-shape with two opposing legs, and the magnets are arranged in pairs facing each other, with the poles of the magnets also facing in opposite directions, i.e., with opposite poles facing each other.

[0055] A coil carrier with at least one coil is arranged between the magnets in a non-contact manner.

[0056] The magnetic actuator further includes a magnetic shield that includes an opening through which the coil carrier protrudes.

[0057] The magnetic actuator may in particular be configured as described above for the vibration isolation system, i.e. have the features described above for the magnetic actuator.

[0058] In particular, the shield has a magnetic permeability μ greater than 1000, preferably greater than 10,000, particularly preferably greater than 50,000. r The material may be made of a material having the formula:

[0059] For example, the magnetic shield is made of mu metal.

[0060] According to one embodiment, a magnetic shield surrounds the magnet carrier.

[0061] According to this embodiment of the invention, the magnetic shield is thus formed as an additional casing which extends around the magnetic actuator known from the prior art.

[0062] This embodiment of the invention has the advantage that the material of the magnetic shield only needs to be optimized for particularly good magnetic shielding.

[0063] According to another embodiment of the invention, the magnetic carrier itself forms part of the magnetic shield.

[0064] That is, according to this embodiment of the invention, the magnet carrier is manufactured from such a material and the legs of the coil carrier and the connecting plates for both legs are dimensioned so as to already form a shield.

[0065] Preferably, for this embodiment of the invention, ferromagnetic soft iron is used rather than mu-metal, as it is inexpensive and easily machined.

[0066] Therefore, the walls acting as a shield must be made thicker than mu-metal to achieve the same shielding.

[0067] The open side of the U-shaped magnet carrier is, according to an embodiment of the invention, provided with a wall that acts as a shield.

[0068] Preferably, the casing, which simultaneously serves as magnet carrier and shield, contains only one opening, into which the coil carrier projects without contact.

[0069] According to one preferred embodiment of the present invention, the magnetic actuator includes at least two opposing magnet pairs in order to generate as much force as possible, with the coil windings arranged between the magnet pairs.

[0070] Therefore, in a particularly advantageous arrangement, at least two opposing pairs of magnets are provided with corresponding windings of a coil arranged therebetween, and preferably two such windings of a coil are also provided.

[0071] In other words, a coil winding is disposed between each pair of opposing magnets, followed at a predetermined distance by another pair of opposing magnets also having a coil winding therebetween, which minimizes the magnetic field required during operation while at the same time allowing good force transmission.

[0072] Thus, a plurality of windings or winding assemblies of the coil are provided, which may be spaced apart from one another and are preferably arranged correspondingly to the opposing magnet pairs. More than two such opposing magnet pairs, each with a winding assembly, may be provided, for example, three magnet pairs with a winding assembly, with a predetermined spacing between these assemblies so that the magnetic field required during operation can be reduced to a minimum. The spacing between adjacent magnet pairs and / or adjacent winding assemblies may be in the range of 1 mm to 60 mm, preferably 2 mm to 20 mm.

[0073] In one particularly advantageous embodiment, the spacing between the coil windings and the magnet is also minimized, advantageously to less than 2 mm, preferably less than 1 mm, so as to likewise minimize the required drive energy.

[0074] In an equally advantageous embodiment, the coil carrier consists of or contains ferromagnetic soft iron for good magnetic permeability in order to promote magnetization in the region of the coil carrier.

[0075] In a further refinement of the invention, the coil carrier can be formed with an additional shield, which can be attached in particular to areas of the coil carrier located outside the shield, and areas or surfaces of the coil carrier between the winding assemblies can also be formed with the shield.

[0076] The subject matter of the invention will be explained in more detail below with reference to an embodiment shown diagrammatically in FIGS. 1 to 3 and with reference to the perspective views of an embodiment shown in FIGS. [Brief explanation of the drawings]

[0077] [Figure 1] 1 is a schematic cross-sectional view of a first embodiment of the present invention, in which a magnetic actuator has a housing made of a material with high magnetic permeability as a magnetic shield. [Figure 2] 1 is a schematic diagram illustrating an alternative embodiment of the present invention, in which the magnet carrier of the magnet actuator is at the same time part of the magnetic shield. [Figure 3] 1 is a schematic diagram of a vibration isolation system incorporating a magnetic actuator according to the present invention; [Figure 4] FIG. 1 is a perspective view of a vibration isolator equipped with two magnetic actuators. [Figure 5] FIG. 10 is a detailed view showing the inside of the magnetic actuator. [Figure 6] FIG. 1 is a top plan view of an experimental setup for determining the magnetic field at predefined intervals relative to a magnetic actuator. [Figure 7] 1A and 1B are perspective views schematically illustrating a magnetic actuator including a magnet and a carrier. [Figure 8]1 is a perspective view that schematically illustrates a magnetic actuator with an improved magnetic shield integrated within or on a carrier. FIG. [Figure 9] 10a and 10b are schematic diagrams illustrating the magnetic field difference based on a comparison of the magnetic fields for magnet pair and coil winding arrangements with increased spacing. [Figure 10] 10a and 10b are schematic diagrams illustrating the magnetic field difference based on a comparison of the magnetic fields for magnet pair and coil winding arrangements with smaller spacing.

[0078] Detailed Description of the Drawings 1 shows in schematic cross-section one embodiment of a magnetic actuator 1. The magnetic actuator 1 is configured for use in a vibration isolation system.

[0079] The magnet actuator 1 includes a magnet carrier 2 .

[0080] The magnet carrier 2 is U-shaped and includes two opposing legs 5a, 5b which are joined to each other on one side by a plate 6.

[0081] In this embodiment, two opposing magnet pairs 3a, 3b and 4a, 4b are attached to legs 5a, 5b, respectively.

[0082] The magnets 3a, 3b, 4a, 4b are attached, in particular glued, to the legs 5a, 5b.

[0083] The poles of the magnet pairs 3a, 3b and 4a, 4b are opposite to each other, so that a magnetic field extends from one leg 5a to the other leg 5b.

[0084] The magnets 3a, 3b, 4a, 4b are arranged in this embodiment such that the magnetic fields of both magnet pairs 3a, 3b and 4a, 4b are aligned in opposite directions.

[0085] A coil carrier 7, which in this embodiment is formed in the shape of a plate and includes a coil 8, extends contactlessly into the magnet carrier 2. The windings of the coil 8 extend between the magnet pairs 3a, 3b and 4a, 4b.

[0086] By applying a current to the coil 8 and the resulting magnetic field, the magnetic actuator 1 can generate forces in two directions (indicated by the arrows, depending on the direction of the current).

[0087] The coil carrier 7 can, for example, act on the load part to be isolated, but an inverted arrangement is equally possible, in which the magnet carrier 2 is arranged on a vibration-isolated supported load part and the coil carrier 7 acts on the base of the vibration isolation system.

[0088] According to the invention, the magnetic actuator 1 includes a magnetic shield 9 .

[0089] This magnetic shield 9 is formed in this embodiment as a housing for the magnet carrier 2 .

[0090] The magnetic shield 9 includes side walls 10 and a rear wall 11. The front wall is not visible in this cross-sectional view.

[0091] The magnetic shield 9 also extends along the lower surface 19 and the upper surface 20 of the casing formed by the magnetic shield 9 .

[0092] The magnetic shield 9 has only one opening 12 through which the coil carrier 7 extends contactlessly into the casing formed by the magnetic shield 9 and all the way into the magnet carrier 2.

[0093] The opening 12 is preferably shaped so as to leave only a narrow gap extending around the periphery of the coil carrier 7 .

[0094] The magnetic shield 9 is preferably made of mu metal in this embodiment.

[0095] In particular, the shield 9 may be a multi-layer winding of mu-metal.

[0096] FIG. 2 is a schematic diagram of an alternative embodiment of the present invention.

[0097] Unlike the embodiment shown in FIG. 1, the magnet carrier 2 simultaneously serves as a magnetic shield 9 .

[0098] The legs of the magnet carrier 2 are made thicker than in the embodiment shown in FIG. 1 and form the side walls 10 of the magnetic shield 9 .

[0099] A plate 6 connecting the legs 5a, 5b of the magnet carrier 2 serves as the base.

[0100] Unlike magnetic actuators known from the prior art, a rear wall 11 and a front wall (not shown) are provided. Only on the top surface of the casing formed by the magnetic shield 9 is an opening 12, corresponding to Fig. 1, through which the coil carrier 7 with the coils 8a and 8b extends contactlessly into the casing formed by the magnetic shield 9, so that the coil 8 extends along between the magnet pairs 3a, 3b and 4a, 4b.

[0101] Figure 3 is a schematic diagram of a vibration isolation system in which the magnetic actuator shown in Figure 1 or 2 is used.

[0102] The magnet isolation system 13 is configured as an active vibration isolation system and includes a plate 14. The plate 14 is vibration-isolated and supported on a vibration isolator 15, for example an air spring.

[0103] Plate 14 serves to house equipment (not shown) for processing semiconductor devices.

[0104] In this embodiment, the magnetic actuator 1 is integrated into the casing of a vibration isolator 15 for active vibration isolation.

[0105] The vibration isolation system is configured so that the magnetic field induced by the magnetic actuator during operation is always less than 10 nT at the center of the plate 14 .

[0106] The vibration isolation system includes at least one sensor 16 in the vibration-isolated supported load and / or in the floor 17 .

[0107] The signals of the one or more sensors 16, 17 are processed by a controller 18. The controller 18 controls the magnetic actuator 1 to actively damp vibrations, and thus acts to block the transmission of vibrations acting on the system from the outside.

[0108] Furthermore, it can also act to counteract vibrations caused by vibration-isolated and supported load parts, such as a movable stage (platform).

[0109] Due to the magnetic shield 9 of the magnetic actuator 1, the magnetic actuator 1 can also be placed in the vicinity of equipment that is sensitive to magnetic fields.

[0110] 4 shows a perspective view of one embodiment of vibration isolator 15. Vibration isolator 15 includes a lower portion 21. Lower portion 21 is coupled to the floor in an assembled state.

[0111] Furthermore, the vibration isolator 15 includes an upper portion 22. This upper portion 22 is connected to the vibration-isolated load part, in particular to the plate (reference numeral 14) shown in FIG.

[0112] Between the upper part 22 and the lower part 21 there is a pneumatic spring, which is obscured in this view by the magnetic actuators 1a, 1b.

[0113] The magnetic actuators 1a, 1b are attached in this example to the two corners of the vibration isolator, for example on the edge side.

[0114] The magnetic actuator 1a serves for horizontal vibration isolation.

[0115] The legs 5a can be seen.

[0116] The coil carrier 7 intervenes between the leg 5a and the opposing leg, which is not shown in this view.

[0117] On the edge side, the magnet carriers formed by the legs each have one side 23 arranged thereon, which hides the coil carrier formed by the legs 5a.

[0118] Figure 5 shows a detailed view of a vibration isolator with a partially hidden coil carrier, i.e. the front leg (5a shown in Figure 4) is hidden or removed in both magnet actuators 1a, 1b. The magnet actuator 1b provided for vertical isolation corresponds to the structure shown in Figure 1, in which two magnet pairs with opposite polarities are arranged vertically above each other in the magnet carrier.

[0119] From this viewpoint, the magnets 3a and 4a can be seen.

[0120] Therefore, a compensation force can be generated in the vertical direction based on the control of the coil 8, which is hidden in this line of sight.

[0121] In the magnetic actuator 1a for horizontal isolation, the magnet pairs are rotated by 90°.

[0122] The pair of magnets 3a and 4a visible are not arranged one above the other, but side by side.

[0123] The coil 8 is similarly formed so that its windings extend between the magnet pairs 3a, 3b, 4a, 4b.

[0124] By controlling the coil 8, a compensation force can be generated in the horizontal direction.

[0125] The coil 8, which is for example glued onto the coil carrier 7, has in this embodiment an approximately rectangular cross section in plan view with rounded corners.

[0126] According to the invention, the casing of the magnetic actuators 1a, 1b shown here further comprises a multi-layer cover made of mu metal (not shown), through which the magnetic field generated by the magnetic actuators 1a, 1b is significantly reduced.

[0127] The invention makes it possible in a very simple way to extend the range of use of magnetic actuators in vibration isolation systems.

[0128] 6 shows an experimental setup for determining the magnetic field at predefined intervals relative to a magnetic actuator. The illustrated setup has four vibration isolators 61, which are configured as magnetic actuators. Such an arrangement is particularly stable for accommodating corresponding instruments and devices, in particular for high-precision imaging optical devices such as microscopes, electron microscopes, or transmission electron microscopes.

[0129] In the experimental setup, four vibration isolators 61 are arranged in a uniform rectangular arrangement on a base plate 62, which is particularly suitable for stability reasons. At the center point of the rectangular setup, on the same side of the base plate 62, a magnetic field sensor or magnetometer 60 is mounted to measure the magnetic flux density. The magnetometer 60 measures the magnetic field present during operation of the vibration isolators 61.

[0130] The magnetometer 60 is therefore located in the measurement area relative to the vibration isolators 61, i.e., at the location where a sample is typically measured. In this position, the vibration isolators 61 are spaced from one another by 50 cm to 80 cm. It has been found that the magnetic field excited by the magnetic actuators 61 during operation is less than 10 nT, particularly preferably less than 9 nT. Even if the vibration isolators 61 are spaced even smaller from one another, and thus the distance between the magnetometer 60 and the vibration isolators 61 is even smaller, the strength of the magnetic field excited by the magnetic actuators 61 during operation increases only slightly, so that a distance of less than approximately 70 cm between the vibration isolator(s) 61 and the measurement area, for example a distance of 30 cm to 70 cm or a distance of 35 cm to 65 cm, can also be considered sufficient to enable, for example, the operation of an electron microscope, or in particular a transmission electron microscope.

[0131] The above values ​​for the magnetic field could be achieved for a vibration isolation system in a test environment with a total floor amplitude of 20 μm at 0.5 Hz.

[0132] Figures 7a and 7b show a magnetic actuator 70 with a magnet 72 and a carrier 71. The carrier 71 includes or is made of a single layer of nickel-plated steel. Figure 7b shows a shield 73 surrounding the sidewalls and end faces of the carrier 71. The magnetic shield 73 is made of mu-metal.

[0133] Figure 8 shows a magnet actuator 80 with an improved magnetic shield 83. The magnetic shield 83 is integrated into or to the carrier. In this embodiment, the carrier is made from nickel-plated soft iron, which has improved magnetic permeability over regular steel.

[0134] In this embodiment, the spacing between the coil windings and the magnet is further reduced to a minimum, at approximately 1 mm. The integrated embodiment of the shielding also offers the advantage that the wall thickness can be increased without simultaneously increasing the demand for structural space. In other words, the magnetic shielding is improved by an optimized configuration of the walls, because the walls can be made thicker or the magnetic shielding can work throughout the entire thickness.

[0135] Figures 9a, 9b, 10a and 10b show the comparative differences in the magnetic field for magnet pair and coil winding arrangements with increased spacing (Figures 9a, 9b) and smaller spacing (Figures 10a, 10b).

[0136] In the embodiment of the magnetic actuator 100 shown in Figures 10a and 10b, the spacing between the magnet 101 and the winding assembly 102, i.e., the windings of the coil, or relative to the coil carrier 103, is minimized, advantageously being less than 2 mm, preferably less than 1 mm, whereas this spacing is greater in the embodiment of the magnetic actuator 90 shown in Figures 9a and 9b.

[0137] The embodiment shown in Figures 10a and 10b shows a significantly improved magnetic field formation, thanks to the side shield 104, which has only a small opening 112 for the coil carrier 103 to pass through.

[0138] The present invention therefore makes it possible to provide a high-precision measuring instrument or a high-precision imaging optical device, in particular a microscope, electron microscope or transmission electron microscope, which includes a vibration isolation system with at least three vibration isolators, in particular four vibration isolators, preferably in which at least one vibration isolator includes a magnetic actuator, particularly preferably in which each of a plurality of vibration isolators includes a magnetic actuator.

[0139] The vibration isolation system of the present invention provides improved analysis for users and / or comprehensive usability, for example, in the vicinity of or even within a manufacturing environment, or at times when vibrations should be expected, e.g., on certain days and times.

[0140] This allows for a great deal of freedom in the use of such high-precision measuring instruments, such as electron microscopes or transmission electron microscopes. [Explanation of symbols]

[0141] 1. Magnetic Actuator 2 Magnet Carrier 3a,3b magnet 4a, 4b Magnet 5a,5b Legs 6 plates 7 Coil Carrier 8 coils 9 Magnetic Shield 10 Magnetic shield sidewall 11 Back wall of magnetic shield 12 Magnetic shield opening 13 Vibration isolation system 14 plates 15 Vibration insulators 16 Sensor (load) 17 Sensor (floor) 18 Controller 19 Bottom side 20 Top side 21 Lower part (base part) 22 Upper part 23 Side 60 Magnetic Field Sensor 61 Magnetic Actuator 62 base plate 70 Magnetic Actuator 71 Career 72 Magnet 73 Shield 80 Magnetic Actuator 83 Shield 90 Magnetic Actuator 91 Magnet 92 Winding Assembly 93 Coil Carrier 100 Magnetic Actuator 101 Magnet 102 Winding Assembly 103 Coil Carrier 104 Side Shield 112 Aperture

Claims

1. 1. A vibration isolation system including a vibration-isolated, supported load part, the vibration isolation system including at least one magnetic actuator controlled via a controller, the magnetic actuator acting on the vibration-isolated, supported load part to generate a reaction force to reduce vibrations, the magnetic actuator includes a magnetic shield, a magnet carrier with opposing magnets, and a coil carrier with at least one coil disposed between the magnets; the magnetic shield is formed as a casing having an opening in only one wall, through which the coil carrier protrudes; the magnetic actuator further includes at least two opposing magnet pairs, the at least two magnet pairs being spaced apart from each other, and the windings of the coil extending between the magnet pairs; 10. A vibration isolation system, wherein the poles of the at least two magnet pairs adjacent in the direction in which the windings of the coil extend are alternately opposite in orientation.

2. The vibration isolation system of claim 1 , wherein the windings or winding assemblies of the coil are spaced apart from one another and positioned in correspondence with the opposing magnet pairs.

3. The magnetic shield has a magnetic permeability μ greater than 1000 ｒ 3. The vibration isolation system of claim 1, wherein the material has a

4. 4. The vibration isolation system of claim 1, wherein the magnetic shield is made of mu-metal.

5. 5. A vibration isolation system according to claim 1, wherein an arm of the magnetic actuator projects from the opening.

6. 6. A vibration isolation system according to claim 1, wherein the coil carrier is formed from nickel-plated mild steel.

7. 7. The vibration isolation system according to claim 1, wherein the magnetic actuator is integrated into a vibration isolator.

8. 8. A vibration isolation system according to claim 1, wherein the vibration isolation system comprises at least two magnet actuators for generating compensation signals in at least two spatial directions different from each other.

9. 9. A vibration isolation system according to claim 1, comprising a plate housing equipment to be vibration-isolated and supported, supported on vibration isolators, the vibration isolators including at least one magnetic actuator, and in operation, a magnetic field induced by the magnetic actuator at the center of the plate is less than 15 nT at a distance of less than 70 cm from the at least one vibration isolator.

10. 10. A vibration isolation system according to claim 1, comprising a plate housing equipment to be vibration-isolated and supported, supported on a vibration isolator, the vibration isolator including at least one magnetic actuator, the magnetic field induced by the magnetic actuator at the center of the plate being less than 10 nT.

11. A vibration isolation system according to any one of claims 1 to 10, wherein the spacing between adjacent magnet pairs and / or the spacing between adjacent winding assemblies is in the range of 1 mm to 60 mm.

12. 12. A magnetic actuator for a vibration isolation system according to claim 1, comprising: a magnet carrier with opposing magnets; and a coil carrier with at least one coil arranged between the magnets; wherein the magnetic actuator comprises a magnetic shield, the magnetic shield being formed as a casing with an opening in only one wall, through which the coil carrier protrudes; and wherein the magnetic actuator further comprises at least two opposing magnet pairs, the at least two magnet pairs being spaced apart from each other, the coil windings extending between the magnet pairs, and the poles of the at least two magnet pairs adjacent in the direction in which the coil windings extend are alternately opposite in orientation.

13. The magnetic shield has a magnetic permeability μ greater than 1000 ｒ 13. The magnetic actuator of claim 12, comprising a material having

14. 14. The magnetic actuator of claim 12 or 13, wherein the magnetic shield surrounds the magnet carrier.

15. A magnetic actuator according to claim 12 or 13, wherein the magnet carrier forms part of the magnetic shield.

16. The magnetic actuator according to any one of claims 12 to 15, wherein the wall of the magnetic shield has a thickness of 0.1 mm to 10 mm.

17. 17. The magnetic actuator according to claim 12, wherein the poles of the opposing magnets are opposite to each other.

18. 18. The magnetic actuator according to any one of claims 12 to 17, wherein the magnet carrier is formed in a U-shape.

19. 19. An optical device comprising a vibration isolation system according to any one of claims 1 to 11 with at least one vibration isolator, the at least one vibration isolator comprising a magnetic actuator according to any one of claims 12 to 18.

20. 20. The optical device of claim 19, wherein the vibration isolation system includes a plate containing equipment to be vibration-isolated and supported, supported on vibration isolators, and wherein, during operation, the magnetic field induced by the magnetic actuator at the center of the plate is less than 15 nT at a distance of less than 70 cm from at least one vibration isolator.

21. 21. The optical device according to claim 19 or 20, wherein the optical device is configured as a microscope.

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