CN110325920B

CN110325920B - Plunger coil actuator

Info

Publication number: CN110325920B
Application number: CN201780086778.0A
Authority: CN
Inventors: J.韦塞林
Original assignee: Carl Zeiss SMT GmbH
Current assignee: Carl Zeiss SMT GmbH
Priority date: 2016-12-21
Filing date: 2017-11-23
Publication date: 2021-07-13
Anticipated expiration: 2037-11-23
Also published as: CN110325920A; WO2018114210A1; KR102510772B1; DE102016225900A1; KR20190097170A

Abstract

The invention relates to a plunger coil actuator (1) comprising at least one first coil (15) and one second coil (16) and a magnet arrangement (10), wherein the coils (15, 16) interact with the magnet arrangement (10) such that the magnet arrangement (10) can be deflected within a movement region (17). A central axis (M) of the magnet arrangement (10) if the magnet arrangement (10) is in a rest position not deflected by the coils (15, 16)₃) The pole (X) of the polar coordinate system passing through the moving region (17) extends. The first coil (15) is arranged and configured such that the pole (X) of the polar coordinate system is located inside the circumference (18) of the first coil (15) and the first coil (15) applies an outwardly directed radial force to the magnet arrangement (10), wherein the second coil (16) is arranged and configured to apply a tangential force to the magnet arrangement (10).

Description

Plunger coil actuator

The present application claims priority from german patent application DE 102016225900.8, the contents of which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates to a plunger coil actuator comprising at least a first and a second coil and a magnet arrangement.

The invention also relates to a projection exposure apparatus for semiconductor lithography having an illumination system with a radiation source and an optical unit having at least one optical element.

Background

Plunger-coil actuators, also known as voice coil actuators and voice coil actuators, are based on the known physical phenomenon of lorentz forces and are used for a number of actuator-based tasks in the prior art. As is known, a conductor through which a current flows under the influence of a permanent magnetic field experiences a corresponding force, depending on the current direction and the current strength in the current conductor, which may lead to a deflection of the conductor or the magnet. According to this principle, a rotational movement or a linear (translational) movement can be performed.

Plunger coil actuators are used in particular in projection exposure apparatuses for semiconductor lithography, in order to mechanically influence or manipulate or deform optical elements in their illumination system, for example in order to control the beam path of a radiation source.

DE 102012223034 a1 discloses an illumination system of a microlithographic EUV ("extreme ultraviolet") projection exposure apparatus. In particular, mirror facet flexures for facet mirrors included in illumination systems and their actuation are described herein. Each of the mirror facets may in this case be tiltable about two orthogonal axes by means of an actuator. For this purpose, an actuating element (transducer) which can be moved linearly in two dimensions in the form of a magnet can be controlled mechanically by electromagnetic interaction with a statically mounted coil which influences the transducer. In this case the translator is connected via a flexure to an optical element, for example a mirror facet, so that the movement performed can be transmitted and the mirror can be tilted.

In practice, the plunger coil actuator is usually designed as a DC current linear motor. For this purpose, it is known to arrange two or more ring coils offset from each other at a common height level, the ring coils being able to deflect permanent magnets arranged above or below the coils in the x-direction and in the y-direction of a cartesian coordinate system. In this case, a constant current is required in both coils in order to approach the xy position and also in order to maintain the position.

In the known solutions, it is therefore disadvantageous that, in the event of a deflection of the translator or of the rotor from its undeflected rest position, current must flow into one or more coils of the plunger coil actuator from time to time, so that the translator does not move back into the rest position.

Finally, the waste heat must be dissipated from the coil(s) to the surrounding assembly through a good thermal connection or bypass and kept at acceptable limits for safe use. Especially in the interior of projection exposure apparatus, the heating of components can have a severe adverse effect on the accuracy of the lithographic process, for example if optical components are deformed unevenly by the input of heat.

In particular, since a large number of optical elements, such as, for example, mirror facets, often have to be handled in a projection exposure apparatus, a large number of actuators are required in a closed installation space — the packing density of the projection exposure apparatus is very high, as is known. It is therefore desirable to reduce the size of known actuators or to simplify their construction.

Disclosure of Invention

The invention is based on the object of providing a plunger coil actuator with a compact structure which exhibits only a low current consumption and which can be controlled precisely.

The invention is also based on the object of providing a projection exposure apparatus for semiconductor lithography which comprises a plunger coil actuator with a compact structure and low current consumption for adjusting or operating or deforming an optical element.

For a plunger coil actuator, this object is achieved by the features presented below. For a projection exposure apparatus, this object is achieved by the features presented below. The embodiments and features described below relate to advantageous embodiments and variants of the invention.

The plunger coil actuator comprises at least a first coil and a second coil and a magnet arrangement, wherein the coils interact with the magnet arrangement such that the magnet arrangement is deflectable within a movement region.

A first coil and a second coil are preferably provided. However, even more coils may be provided, for example a third coil and possibly a fourth coil.

The currents in the coils can be individually controlled or adjusted in order to generate a corresponding defined magnetic field. In this case it is also possible to influence the current direction.

The magnet arrangement may be any desired arrangement which generates a magnetic field by which magnetic interaction with the coil is possible. The magnet arrangement may thus be, for example, one or more coils, one or more permanent magnets and/or one or more permanent magnets.

The movement region is a defined movement region in which the plunger coil actuator is able to deflect the magnet arrangement. The magnet arrangement is preferably a transducer or rotor of a plunger coil actuator. The first and second coils may be coupled to a fixed housing part and in this case may be considered part of a stator unit of the plunger coil actuator.

The magnet arrangement of the plunger coil actuator can advantageously be coupled to further elements, so that a relative movement of the magnet arrangement with respect to the one or more coils results in a deflection of the actuating rod of the plunger coil actuator, for example wherein the actuating rod can transmit a movement-translatory direction or directly-for example to a component to be adjusted by the actuator, for example a mirror facet of a facet mirror of a projection exposure apparatus.

There is provision that the central axis of the magnet arrangement extends through the pole of the polar coordinate system of the movement region when the magnet arrangement is situated in the rest position without being deflected by the coil.

The central axis of the magnet arrangement preferably extends orthogonally to the movement region. The magnet arrangement may have any desired geometry and is preferably designed so as to be cylindrical, which then extends along the central axis.

A polar coordinate system (also referred to as a circular coordinate system) is a two-dimensional coordinate system in which each point is defined as a distance and an angle from an origin (pole). The distance from a pole is also referred to as the radius or radial coordinate and the angle is also referred to as the angular coordinate, polar angle or azimuth angle.

The origin of the polar coordinate system, that is to say the pole of the polar coordinate system, is situated according to the invention within the movement region and defines the rest position of the system, such that the system is situated in the rest position when the central axis of the magnet arrangement extends through the pole.

The movement region is preferably designed as a circular region. The pole of the polar coordinate system is very particularly preferably located in the center of the movement region, that is to say for example in the center point of a circle.

According to the invention, it is provided that the first coil is arranged and designed such that the poles of the polar coordinate system lie within the circumference of the first coil.

This allows a particularly suitable deflection of the magnet arrangement in comparison with the prior art, wherein provision is made for the origin of the coordinate system to be located between two ring coils arranged parallel to one another and to have a uniform structure.

According to the invention, it is provided that the first coil applies a radial force directed (radially) outward to the magnet arrangement. This may occur due to the arrangement according to the invention at each relative position of the first coil and the magnet arrangement to each other.

There may be provision for the first coil to magnetically repel the magnet arrangement. Although preference is given to a radial repulsive force, there may also be provision that the first coil applies a radial attractive force to the magnet arrangement. The outwardly oriented radial force may thus have any desired sign.

According to the invention, it is also provided that the second coil arrangement is designed to apply a tangential force to the magnet arrangement. This may occur in any relative position where the magnet arrangement is located relative to the second coil.

It should be noted, however, that there may be one or more relative positions where the arrangement is located at a dead centre where the magnetic balance is dominant due to symmetry, and therefore may not be directly deflectable from that position. This will be explained in more detail below.

By means of the described structure, it is possible to provide a plunger coil actuator which can be used in an optimal manner in a system, the movement of which can advantageously be defined by means of a polar coordinate system. It is particularly advantageous if the relationship between two points can be more easily described in terms of angle and distance than the conventional x-and y-coordinates of a cartesian coordinate system.

The invention can be used very particularly advantageously if deflection along one of the coordinates of the polar coordinate system (for example along the angular coordinate) requires only a current pulse in order to change the position, and no continuous current is required to maintain the coordinates. In this case, the current requirement in at least one of the coils can be significantly reduced, whereas in the prior art current has to flow continuously through both coils in order to be deflected into the xy position.

Especially in case the system needs to adjust the transducer within a movement area in two dimensions, and it is very especially preferred if the movement area has a circular geometry, that the plunger coil actuator according to the invention can be used more efficiently than a conventional two-dimensional actuator or plunger coil actuator.

Many systems of this type are known from robotics. The invention can, however, very particularly preferably be used for adjusting optical elements of a projection exposure apparatus. The invention should in principle not be considered as being limited to a particular application and is therefore suitable for use in all actuator systems or driver technologies.

The invention can be further extended by the skilled person from a two-dimensional actuator to a three-dimensional actuator by using a spatial or cylindrical coordinate system instead of a polar coordinate system, wherein the height of the pole is increased as an additional coordinate which may be able to be influenced e.g. by a third coil.

By virtue of the construction according to the invention consisting of only a small number of coils, preferably a first coil and a second coil, the plunger coil actuator has a relatively simple construction. The invention can therefore be used very advantageously if a high packing density of many such actuators is required, for example in a projection exposure apparatus.

In a development of the invention, provision is made for the central axis of the first coil to extend through a pole or to extend adjacent to a pole of a polar coordinate system of the displacement region.

The central axis of the first coil extends in this case preferably orthogonally to the region of movement.

Especially with reference to a compact and balanced structure, it may be advantageous that the central axis of the first coil extends close to the pole of the polar coordinate system, or preferably extends through the pole. For example, provision may be made for the central axis of the first coil to extend offset relative to the pole by less than a quarter of the diameter of the first coil, preferably by less than an eighth of the diameter of the first coil relative to the pole, and very particularly preferably through the pole of the polar coordinate system.

A slight offset of the contour of the central axis of the first coil with respect to the poles of the polar coordinate system may be advantageous in order to ensure, without further measures, that the first coil is able to deflect the magnet arrangement away from a rest position in which the central axis of the first coil extends through the poles.

In a development, provision may also be made for the first coil to be designed and/or arranged such that, when the magnet arrangement is deflected by the first coil, the central axis of the magnet arrangement extends within the circumference of the first coil or is arranged within the circumference of the first coil. The magnet arrangement can thus be deflected by the first coil in each position within the provided movement region in a particularly simple, efficient and reliable manner, and the position of the magnet arrangement can be influenced by the first coil.

The movement area preferably lies completely within the circumference of the first coil.

The plunger coil actuator therefore has a particularly good efficiency, since the magnetic interaction decreases with the distance between the coil and the magnet arrangement. The design also allows for a compact structure.

In one development of the invention, provision may be made for the coil and the magnet arrangement to be arranged and/or designed such that a radial force exerted by the first coil on the magnet arrangement brings about a movement of the magnet arrangement along a radial coordinate of the polar coordinate system, and a tangential force exerted by the second coil on the magnet arrangement brings about a movement of the magnet arrangement along an angular coordinate of the polar coordinate system.

For example, provision may be made that, in the arrangement of the coil and the magnet arrangement, the magnet arrangement is mounted in the rest position with a spring, so that the spring returns the magnet arrangement to the rest position if the coil is not energized. The outwardly directed radial force on the magnet arrangement from the first coil (in the energized state) can thus deflect the magnet arrangement along the radial coordinate of the polar coordinate system within the movement region. By means of the tangential force applied to the magnet arrangement by the second coil, a circular path can then be imposed to the magnet arrangement along the angular coordinate of the polar coordinate system.

The above-described design and arrangement of the coils (such that they exert a radial or tangential force) facilitates the deflection of the magnet arrangement irrespective of how the magnet arrangement reaches the rest position or whether a return force actually occurs in the rest position.

In a development of the invention, it can also be provided that the first coil is designed as a spiral-shaped flat coil and/or the second coil is designed as a loop coil.

The spiral flat coil is also referred to as a "flat coil". This is a coil, the winding of which is usually wound in a spiral shape over one height. Such a coil can be used particularly advantageously for applying a radial force acting radially outwards or inwards to the magnet arrangement.

The toroidal coil is also referred to as a circular toroidal coil, a toroidal coil or a toroidal core coil. The annular coil may have, for example, a circular geometry or an angular geometry. Preferably providing a circular geometry. The use of such coils enables an efficient application of tangential forces to the magnet arrangement.

In a development, provision can also be made for the magnet arrangement to have a magnetization direction which extends orthogonally to the region of movement.

In a particularly preferred development, the first coil may be arranged closer to the magnet than the second coil.

The arrangement described above is particularly relevant for the rest state and the operating state.

Since in practice it is often provided in particular that the movable parts of the plunger coil actuator, that is to say also the magnet arrangement, are mounted, which mounting usually causes a return force to the rest position, the inventors have recognized that the efficiency of the magnetic interaction between the first coil and the magnet arrangement, which leads to a radial deflection, is greater than the efficiency of the magnetic interaction between the second coil and the magnet arrangement. In particular, if the installation space is limited, it may therefore be advantageous to configure the first coil to be arranged closer to the magnet than the second coil. Thus, the current consumption within the first coil can be reduced in order to deflect the magnet arrangement radially, so that the current consumption and thus the efficiency of the entire plunger coil actuator can be improved.

In an advantageous development of the invention, provision may be made for the central axis of the first coil and the central axis of the second coil and/or the central axis of the magnet arrangement to extend coaxially.

The central axis of the second coil preferably extends orthogonally to the movement area.

A particularly efficient and space-saving construction can thereby be achieved. The first coil, second coil and magnet arrangement are preferably arranged in a stacked manner. As an example, an arrangement may be provided wherein the first coil is provided directly under the magnet arrangement and the second coil is provided under the first coil. A configuration may also be advantageous in which the first coil is arranged above the magnet arrangement and the second coil is arranged below the magnet arrangement.

Within the scope of the invention, in principle any desired arrangement of the magnet arrangement and of the coil relative to one another is possible.

In a particularly preferred development, the first coil is situated between the second coil and the magnet arrangement.

In one development of the invention, provision is made for at least one core, which concentrates the magnetic flux, to be arranged in the first coil and/or in the second coil.

The efficiency of the magnetic interaction can be improved by the iron core within the coil. It should be noted here, however, that the iron core can cause an additional return force of the magnet arrangement into the undeflected rest position by means of a magnetic attraction force between the magnet arrangement and the iron core.

In particular, if the second coil is designed as a toroidal coil, an iron core can advantageously be provided within the second coil. The toroidal coil may then be wound around a core, such as a toroidal core.

In a development, provision may be made for a control and/or regulating unit to be provided in order to control or regulate the deflection of the magnet arrangement.

Further means, in particular a sensor system for detecting the position of the magnet arrangement with respect to the coil, may also be provided in order to control or adjust the magnet arrangement.

A current sensor, such as an eddy current sensor, may preferably be used to detect the position of the magnet arrangement within the movement area. The radial position of the magnet arrangement may also be determined by the current consumption of the first coil. Any desired sensor can in principle be used for detecting the position of the magnet arranged within the movement area, for example an optical sensor, a capacitive sensor or a magnetic sensor.

In an advantageous development of the invention, electrical and/or magnetic means may be provided in order to avoid that the first coil and the magnet arrangement adopt a relative position with respect to each other that results in a magnetic force balance such that the first coil cannot apply any outwardly oriented radial force to the magnet arrangement.

In the theoretical case of force balance, the following may be the case: despite the energization of the first coil and/or the second coil, the magnet arrangement can no longer be deflected from this so-called "dead point". This can be a problem, in particular in the case of a symmetrical construction of the plunger-coil actuator, which is advantageous in principle.

The spring force may be set, for example, by a suitable suspension or by mounting a magnet arrangement, which avoids such a relative position. Alternatively or additionally, dead spots may be avoided by a suitable electric drive system, which excludes deflections which would lead to dead spots.

Electrical and/or mechanical means may also be provided to deflect the magnet arrangement away from such relative position where the magnetic balance prevails.

As an example, a high current pulse in one or both coils may in practice cause the magnet arrangement to move out of the dead center or to swing out, so that the plunger coil actuator can then be used normally.

According to a particularly preferred development, the magnet arrangement has at least one permanent magnet. The magnet arrangement very particularly preferably has exactly one permanent magnet or is designed as a permanent magnet.

By virtue of the fact that at least one permanent magnet is provided within the magnet arrangement or that the magnet arrangement is designed as a permanent magnet, the plunger coil actuator can be designed more efficiently, more compactly and with more current-saving properties. The at least one permanent magnet does not require any additional power supply means or any current to be applied during operation of the magnetic interaction of the first coil and the second coil, as compared to the coil or to the permanent magnet.

In a development of the invention, provision may also be made for at least one permanent magnet to have a magnetization such that the pole boundary between the two poles of the permanent magnet has a curved contour.

The pole boundaries typically extend in a straight line between the two poles and thus separate the poles of the permanent magnet. When manufacturing permanent magnets, however, it is also possible to set the magnetization resulting in a non-linear profile of the pole boundaries.

As an example, the magnetic circuit may be simulated or calculated beforehand, by means of which the optimum magnetization of the magnet arrangement may be determined. Magnetic circuit is considered to mean an interaction, in particular a magnetic coupling of magnetic components or basic components (in particular coil and magnet arrangements) of a plunger coil actuator.

By means of a specified magnetization of the magnet arrangement, the situation can be achieved in that the power consumption of the plunger coil actuator is independent of the radial coordinate and the angular coordinate. This may thus result in a uniform heat dissipation of the plunger coil actuator independent of the deflection position of the magnet arrangement with respect to the coil. The thermal behavior of the system can thus be better calculated and more uniform. The motor constant of the plunger coil actuator can thus be designed to be constant, that is to say independent of the deflection of the transducer (or rotor) of the magnet arrangement.

Alternatively or additionally, the first coil and/or the second coil may be designed or oriented such that a constant current consumption is achieved within the movement region irrespective of the position of the magnet arrangement with respect to the deflection of the coils.

The invention also relates to a projection exposure apparatus for semiconductor lithography having an illumination system with a radiation source and an optical unit with at least one optical element which can be adjusted and/or manipulated and/or deformed by a plunger coil actuator as claimed above.

The features and advantages which have already been described in connection with the above-described plunger coil actuator according to the invention can also be used in any desired combination in the case of a plunger coil actuator of a projection exposure apparatus.

In a development of the projection exposure apparatus, at least one of the optical elements can be designed as a facet mirror, wherein the facet mirror has a carrier structure and a plurality of individually adjustable mirror facets carried thereby, wherein each mirror facet is connected to the carrier structure via a flexure such that the mirror facet can be tilted with respect to two axes which are orthogonal to one another, wherein the mirror facet is rigidly connected to an actuating rod, and wherein the actuating rod can be deflected by a plunger coil actuator in order to tilt the mirror facet with respect to at least one of the two axes.

In such an arrangement, as described in detail in, for example, DE 102012223034 a1 (the disclosure of which is incorporated herein by reference), the deflection of the actuating rod may be particularly advantageous when connecting the actuating rod to a magnet arrangement, in particular in the case of driving based on a polar coordinate system.

Drawings

Exemplary embodiments of the present invention are explained in more detail below with reference to the accompanying drawings.

The figures each show a preferred exemplary embodiment in which individual features of the invention are explained in combination with one another. Features of the exemplary embodiments can also be implemented independently of other features of the same exemplary embodiments and can therefore be combined with features of other exemplary features by a person skilled in the art to form further advantageous combinations and sub-combinations.

In the figures, elements that are functionally identical are provided with the same reference numerals.

Schematically, in the drawings:

figure 1 shows an EUV projection exposure apparatus;

fig. 2 shows a further projection exposure apparatus;

FIG. 3 shows a top view of a facet mirror;

FIG. 4 shows an isometric view of a mirror facet and an isometric view of a flexure with an actuating rod;

figure 5 shows a cross-sectional view of a plunger coil actuator according to the present invention in a first configuration;

FIG. 6 shows a substantially top view of a plunger coil actuator according to the present invention;

FIG. 7 shows exemplary current curves for a first coil and a second coil;

figure 8 shows a cross-sectional view of a plunger coil actuator according to the present invention in a second configuration;

FIG. 9 illustrates an exemplary toroidal coil;

FIG. 10 illustrates an exemplary spiral-shaped flat coil;

figure 11 shows a cross-sectional view of a plunger coil actuator according to the invention in a third configuration; and

fig. 12 shows a cross-sectional view of a magnet arrangement consisting of a plurality of permanent magnets.

Detailed Description

Fig. 1 shows, by way of example, the basic structure of an EUV projection exposure apparatus 400 for semiconductor lithography, to which the invention can be applied. In addition to the radiation source 402, the illumination system 401 of the projection exposure apparatus 400 comprises an optical unit 403 which illuminates an object field 404 in an object plane 405. A reticle 406 arranged in the object field 404 is illuminated, which reticle is held by a schematically illustrated reticle holder 407. The projection optical unit 408, which is only schematically illustrated, is used for imaging the object field 404 into an image field 409 within an image plane 410. The structures on the reticle 406 are imaged onto a photosensitive layer of a wafer 411 arranged in the region of an image field 409 in an image plane 410, which wafer is held by a wafer holder 412, which is likewise partially illustrated. The radiation source 402 may emit EUV radiation 413, in particular in the range between 5 nm and 30 nm. Optically differently designed and mechanically adjustable

optical elements

415, 416, 418, 419, 420 are used to control the radiation path of the EUV radiation 413. In the case of the EUV projection exposure apparatus 400 illustrated in fig. 1, the optical elements are designed in suitable embodiments as adjustable mirrors, which are mentioned below merely as examples.

EUV radiation 413 generated by the radiation source 402 is collimated by a collector integrated in the light source 402 such that the EUV radiation passes through an intermediate focus in the region of the intermediate focal plane 414, and the EUV radiation 413 is then incident on the field facet mirror 415. Downstream of the field facet mirror 415, the EUV radiation 413 is reflected by a pupil facet mirror 416. The field facet of the field facet mirror 415 is imaged into the object field 404 by means of a pupil facet mirror 416 and an optical assembly 417 with

mirrors

418, 419, 420.

Fig. 2 shows a further projection exposure apparatus 100, for example a DUV ("deep ultraviolet") projection exposure apparatus. The projection exposure apparatus 100 comprises an illumination system 103, a device known as a reticle stage 104 which receives and precisely positions a reticle 105 from which subsequent structures on the wafer 102 are determined, a facility 106 which holds, moves and precisely positions the wafer 102, and in particular an imaging facility of a projection lens 107 having a plurality of optical elements 108, which optical elements 108 are held in a lens housing 140 of the projection lens 107 by means of a mount 109.

The optical element 108 may be designed as a separate refractive, diffractive and/or reflective optical element 108, such as a lens element, a mirror, a prism, a stop plate, etc.

The basic functional principle of the projection exposure apparatus 100 is to image structures introduced into the reticle 105 onto the wafer 102.

The illumination system 103 provides a projection beam 111 in the form of electromagnetic radiation, which is required for imaging the reticle 105 on the wafer 102. A laser, a plasma source, or the like may be used as a source of the radiation. The optical elements in the illumination system 103 serve to shape the radiation such that the projection beam 111 has the desired properties with respect to the diameter, polarization, shape, etc. of the wavefront when the radiation is incident on the reticle 105.

An image of the reticle 105 is produced by projecting a light beam 111 and is transferred from the projection lens 107 onto the wafer 102 in a suitably reduced form. In this case, the reticle 105 and the wafer 102 can be moved synchronously, so that during a so-called scanning operation, in practice, regions of the reticle 105 are imaged successively onto corresponding regions of the wafer 102.

Fig. 2 shows the arrangement of the manipulator 200 in the region between the reticle stage 104 and the first optical element 108 of the projection lens 107. The manipulator 200 is used for correcting image aberrations, the optical elements contained therein being mechanically deformed by the actuator system.

The use of actuators of various designs is known for adjusting and/or manipulating the

optical elements

415, 416, 418, 419, 420, 108 of the

projection exposure apparatus

400, 100 illustrated in fig. 1 and 2, and for adjusting and/or manipulating the

wafers

411, 102.

Fig. 5, 6, 8 and 11 show a plunger-coil actuator 1 according to the invention in various embodiments.

The plunger coil actuator according to the invention is particularly suitable for orienting or for tilting individual mirror facets 2 of a field facet mirror 415 of a projection exposure apparatus 400 (see fig. 3 and 4). Of course, the invention is also well suited for orienting or tilting any other desired optical element of any desired projection exposure apparatus. The plunger coil actuator 1 according to the invention can also be used to influence the manipulator 200.

The use of the invention is not restricted to use in the

projection exposure apparatus

100, 400, in particular also not to the described structure.

The present invention and the following exemplary embodiments should also be considered as not being limited to the specified designs.

Fig. 3 shows a facet mirror, for example a field facet mirror 415, in a plan view. A carrier plate 3 can be seen, the surface 4 thereof facing the viewer preferably being largely covered by the mirror facet 2. The contours of the mirror facets 2 in this case preferably each have the shape of a ring segment. The mirror facets 2 can thus be arranged in a closely grouped row. The coverage of the surface 4 with the mirror facets 2 is preferably in the range of more than 80%, so that only a small amount of EUV radiation 413 from the radiation source 402 impinges between adjacent mirror facets 2.

For example, 300 or more mirror facets 2 can be provided on the carrier plate 3. The diameter of the field facet mirror 415 may be, for example, 80 cm.

Each mirror facet 2 may be individually adjustable such that the impinging EUV radiation 413 can be directed onto different target points (e.g. pupil facet mirror 416).

Fig. 4 shows an isometric view of how the mirror facet 2 is connected via a flexure 5 to a fixed sleeve 6 having an annular cross-section. The fixing sleeve 6 forms, together with the carrier plate 3 shown in fig. 3, a carrier structure of the mirror facets 2, relative to which the mirror facets 2 can be tilted. For the sake of simplicity, fig. 4 does not show the carrier plate 3. The fixing sleeve 6 can be fixed to the carrier plate 3 by a fixing sleeve 6 extending through the carrier plate 3.

In the exemplary embodiment illustrated, the mirror facets 2 are preferably eccentrically carried by a carrying element 7 having the shape of a circular disc. An actuating rod 8 extending through the fixing sleeve 6 is arranged centrally on the underside of the carrier element 7. End pieces 9 are arranged at opposite ends of the actuating rod 8, on which end pieces the plunger coil actuator 1 according to the invention (not shown in fig. 4) can act in order to tilt the mirror facets 2. The end piece 9 may in particular be a transducer of the plunger coil actuator 1 or a magnet arrangement 10 as described below. As an alternative, the end piece 9 may be fixed to the transducer or to the magnet arrangement.

The flexure 5 connects the actuating rod 8 to the fixed sleeve 6. To this end, the flexure comprises three engagement brackets 11 arranged around the actuating rod 8 and fixed at one end to the inner surface of the fixing sleeve 6 and at the other end to the carrying element 7. Here, the angles between adjacent engagement brackets 11 are preferably each 120 °. If the joining brackets 11, as shown by the broken lines in fig. 4, actually extend beyond the carrier element 7, the joining brackets 11 will meet at an oblique point 12 at least approximately on the reflective coating of the mirror facet 2.

In the undeflected state, the end piece 9 or the magnet arrangement 10 is seated in a defined rest position.

If the actuating rod 8 is deflected by means of the plunger coil actuator 1, as shown in fig. 4 by the arrow 13, the mirror facet 2 pivots about the tilting point 12 in the event of a bending of the engagement leg 11. The bending stiffness of the engagement legs 11 thus defines a bending resistance that has to be overcome by the plunger coil actuator 1 in order to tilt the mirror facets 2. Due to the uniform distribution of the joint supports 11 in the vicinity of the actuating rods 8, the bending resistance of the flexures 5 is approximately isotropic, so that the flexures 5 exhibit approximately the same bending resistance in opposition to the tilting of the mirror facets 2 about each of the two orthogonal tilt axes.

The result of this construction is also that the plunger coil actuator 1 (in particular in the case of radial deflection of the end piece 9 or the magnet arrangement 10) has to counteract the return force of the flexure 5. In contrast, the end piece 9 or the magnet arrangement 10 can move along a circular path around the rest position with a constant radial deflection, without the flexure 5 significantly counteracting the circular movement.

Furthermore, a bellows 14 extends between the carrier element 7 and the fixed sleeve 6, said bellows preferably closing off an intermediate space between the mirror facet 2 and the fixed sleeve 6 in a gas-tight manner with respect to an external space. The bellows 14 prevents, firstly, small particles separated by parts of the flexure 5 due to mechanical or thermal loads from passing into the external space and from adversely affecting the function of the lighting system 401 due to, for example, deposits on the mirror surfaces. The bellows 14 additionally ensures that the mirror facets 2 do not rotate about the longitudinal axis of the bellows 14, that is to say about an axis perpendicular to the surface.

Fig. 5 depicts a cross-sectional view of a plunger coil actuator according to the invention in a first embodiment. The plunger coil actuator 1 comprises a first coil 15 and a second coil 16 and the already mentioned magnet arrangement 10, the

coils

15, 16 magnetically interacting with the magnet arrangement 10. The magnet arrangement 10 can in this case be deflected within the movement region 17. The magnet arrangement 10 is in this case and preferably simultaneously the end piece 9 of the actuating rod 8 of fig. 4.

In the exemplary embodiment, the first coil 15 is designed as a spiral-shaped flat coil and the second coil 16 is designed as a ring coil.

The magnet arrangement 10 preferably has permanent magnets. In the exemplary embodiment, the magnet arrangement 10 is preferably designed as a permanent magnet 22. In an exemplary embodiment, the permanent magnet 22 has a magnetization direction that extends orthogonally (indicated by the arrow in the figure) to the moving region 17. The permanent magnet 22 has two

poles

22b, 22c separated by a pole boundary 22 a.

The diameter of the magnet arrangement 10 or the permanent magnet 22 may be, for example, 10 mm.

The movement area 17 is limited in its extent, as shown in fig. 5 by way of example in the form of a dashed line. In the exemplary embodiment, provision is made for the displacement region 17 to extend completely within the circumference 18 of the first coil 15 and the second coil 16, that is to say not to protrude beyond the region of the

coils

15, 16 as seen in top view.

In the exemplary embodiment there is also provision for the central axis M of the first coil 15 to be when the magnet arrangement 10 is situated in a rest position (as illustrated in fig. 5) which is not deflected by the

coils

15, 16₁And the central axis M of the second coil 16₂And a central axis M of the magnet arrangement 10₃Extending coaxially. In the rest position, the central axis M of the magnet arrangement 10₃But also extends through the pole X of the polar coordinate system. The moving region 17 spans within the polar coordinate system. The origin X of the coordinate system, that is to say the pole X, thus defines the rest position of the translator (magnet arrangement 10 or permanent magnet 22) of the plunger coil actuator 1 (as illustrated in fig. 6).

There is provision to arrange and design the first coil 15 such that the pole X of the polar coordinate system is located within the circumference 18 of the first coil 15 and the first coil 15 applies an outwardly oriented radial force to the magnet arrangement 10. Furthermore, the second coil 16 is arranged and designed so as to apply a tangential force to the magnet arrangement 10.

In an exemplary embodiment there is also provision that the first coil 15 is arranged closer to the magnet arrangement 10 than the second coil 16. The

coils

15, 16 and the magnet arrangement 10 are preferably arranged in relation to each other in a stacked manner. In this case, the first coil 15 is arranged between the magnet arrangement 10 and the second coil 16. A separation region 19, on which the magnet arrangement 10 can move, is also situated between the first coil 15 and the magnet arrangement 10. There may be provision for the separation zone 19 to separate vacuum from air. Preferably, the flexure 5, the magnet arrangement 10 and the mirror facet 2 are arranged in a vacuum and the

coils

15, 16 are arranged in air. This is particularly advantageous if the invention is used in an EUV projection exposure apparatus 400, since the optical unit 403 can be arranged completely in a vacuum, while the thermally critical components of the plunger coil actuator 1 (in particular the coils 15, 16), which may be cooled, are arranged outside the vacuum.

Fig. 6 illustrates a basic top view of a plunger coil actuator 1 according to the invention. The deflection of the magnet arrangement 10 in a polar coordinate system is intended to be explained in particular here.

An exemplary offset position of the magnet arrangement 10 within the polar coordinate system and within the movement region 17 is illustrated here. Further the subsequent position 20 is depicted in dashed line form.

In the exemplary embodiment, the magnet arrangement 10 is preferably designed cylindrically. The circumference 18 of the first coil 15 preferably corresponds to the circumference of the second coil 16. As an example, fig. 6 illustrates in dashed line form the circumference 18 of the

coils

15, 16 below the separation region 19. In the exemplary embodiment, provision is made in particular for the displacement region 17 to lie completely within the circumference 18 of the

coils

15, 16. However, the first coil 15 may in principle be sufficiently designed and/or arranged such that the central axis M of the magnet arrangement 10 is deflected by the first coil 15 when the magnet arrangement 10 is deflected₃Extending within the circumference 18 of the first coil 15. The displacement area 17 may thus have a larger circumference than the circumference 18 of the first coil 15.

For example, there may be provision that the diameter of the displacement region 17 is 3 mm. The magnet arrangement 10 can thus be adjusted in one direction by up to 3 mm.

In fig. 6, the magnet arrangement 10 is illustrated along a radial coordinate r of a polar coordinate system₁Offset from the pole X of the polar coordinate system. Magnet arrangement 10 also has an angular coordinate along a polar coordinate system

And (4) deflecting. Each point within the movement area 17 can thus be represented by the radial coordinate r and the coordinate of the polar coordinate system

To be mapped.

Due to the specific design of the flexure 5 as shown in fig. 4, the deflection of the magnet arrangement 10 and the subsequent maintenance of this position requires a constant current through the first coil 15, since the magnet arrangement 10 experiences a constant current due to the engagement of the support 11The return force. In contrast, in an ideal case, the magnet arrangement 10 can follow the angular coordinates of a polar coordinate system

Move without force. Only the second coil 16 must be energized to follow the angular coordinate

Changing the position of the magnet arrangement 10 or accelerating the magnet arrangement 10. It is not necessary to energise the second coil 16 to maintain position.

Fig. 7 illustrates, by way of example, the current curve I of the drive coils 15, 16_r(t)、

In this case, the current curve I of the first coil 15_r(t) shows the case where the magnet arrangement 10 is intended to be deflected from an undeflected rest position (time t 0) to a particular radial coordinate r₁I.e. starting from the pole X to a certain radial coordinate r₁(see fig. 6). This results in principle in the current coil I_rAnd radial distance r from pole X, the current demand of the first coil 15 increases as the radial distance r increases due to the return force of the flexure 5. Current curve I of the first coil 15_r(t) thus shows the current I_rAt a time interval T₁Rises internally and then at a time interval T₂And is kept constant. This corresponds to the time interval T₁Inner approximate radial position r₁And then at a time interval T₂Maintaining the radial position r₁. Can in principle be based on the coil current I_rThe corresponding radial distance r of the pole X is intentionally predefined or detected.

Current curve of the second coil 16

It is shown that the magnet arrangement 10 can be driven to change between two angular coordinates of a polar coordinate system. As already described, in the ideal case, the magnet arrangement 10 is angularly oriented with the same radial deflection rCan occur without force. In order to relate to the angular position of the magnet arrangement 10

A change of position is made to a subsequent position 20, for example as illustrated in fig. 6, the second coil 16 first being in the time interval T₃May have a current pulse applied to it, the magnet arrangement 10 is thus forced to move rotationally about the central axis X or about the pole X, because the second coil 16 applies a tangential force to the magnet arrangement 10 and converts the tangential force into a rotational movement due to the mounting of the flexure 5. The magnet arrangement 10 is then at a time interval T₄During which it is rotated further until it is at a time interval T₅To its desired final position (e.g., position 20 in fig. 6). To stop the magnet arrangement 10, the second coil 16 may then have a reverse current pulse applied thereto.

A control and/or adjustment unit 24, illustrated in dashed lines, may be provided in order to control or adjust the deflection r, of the magnet arrangement 10,

Such control or regulation can in particular be of diagonal coordinates

Is advantageous. A sensor unit may be provided here in order to detect the current angular position of the magnet arrangement 10

And/or the radial coordinate r and used for adjustment or control.

Fig. 8 shows a second embodiment of a plunger coil actuator 1 which essentially corresponds to the first embodiment of fig. 5, so that the features already described above will not be discussed again. The second coil 16, which is preferably a toroidal coil, has a core 21 that concentrates the magnetic flux, as compared to the first embodiment. The efficiency of the second coil 16 can thereby be improved, which may be advantageous in terms of the efficiency of the plunger coil actuator 1, in particular because the second coil 16 is further from the magnet arrangement 10 than the first coil 15.

Since the first coil is arranged closer to the magnet arrangement 10, an effective construction of the plunger coil actuator 1 can in principle be ensured, since, as already mentioned, a constant current I through the first coil 15_rIs necessary in order to continuously deflect the magnet arrangement 10 with respect to the radial coordinate r. It is therefore advantageous that the current I through the first coil 15 must be reduced as much as possible for this purpose_rAnd the magnetic interaction between the first coil 15 and the magnet arrangement 10 is designed to be as efficient as possible.

Fig. 8 shows the magnet arrangement 10 deflection radius r for ease of illustration₁The state of (1).

Fig. 9 illustrates a top view of the second coil 16 as a circular coil having a core 21 in the embodiment. For clarity, only a small number of windings are shown.

Fig. 10 illustrates the first coil 15 as a spiral-shaped flat coil in an embodiment in a top view.

Fig. 11 also shows a third exemplary embodiment of a plunger-coil actuator 1, which is likewise designed in principle so as to be similar to the first exemplary embodiment of fig. 5. Unlike in fig. 5, the magnet arrangement 10 or the permanent magnet 22 has a magnetization such that the pole boundary 22a between the two

poles

22b, 22c of the permanent magnet 22 has a curved contour. Therefore, the current consumption I of the first coil 15_rCan be independent or largely independent of the radial coordinate r.

Without further measures, the motor constant of the plunger coil actuator 1 (e.g. the plunger coil actuator 1 of the exemplary embodiment) is not constant during the deflection of the magnet arrangement 10 over the movement region 17.

In the case of a deflection of the magnet arrangement 10 starting from the rest position X, the efficiency of the plunger coil actuator 1 constantly increases, since the magnetic flux increases when the magnet arrangement 10 passes in the outer region of the

coils

15, 16. At the same time, however, the mechanical return force from the flexure 5 also increases outwards. The person skilled in the art then designs the plunger coil actuator 1 within the overall system, for example with regard to the

coils

15, 16 and the magnet arrangement 10 relative to one another or other designs and arrangements based on the magnetization of the magnet arrangement 10, such that the power consumption of the

coils

15, 16 is constant or at least approximately constant in the optimum case when the magnet arrangement 10 is moved over the movement region 17, so that the current output or the heat output of the plunger coil actuator 1 can be handled well and in particular it is not possible to have an inhomogeneous heat input from a plurality of plunger coil actuators 1 of the projection exposure apparatus 400. Suitable geometries of the coil(s) or magnet arrangement or arrangements of the coil(s) or magnet arrangement may be derived from simulations, calculations and/or experiments.

Fig. 12 shows, by way of example and in abstract form, a cross-sectional view of a magnet arrangement 10 made up of a plurality of permanent magnet elements 23. The permanent magnet elements 23 are in this case designed as ring magnets and are oriented relative to one another such that a curved magnetization occurs, similar to the magnetization of the permanent magnet 22 illustrated in fig. 11 with the pole border 22 a. In this way, it is likewise possible to set a constant or as constant as possible current consumption or power consumption of the plunger coil actuator 1, irrespective of the deflection of the magnet arrangement 10.

At the center of the arrangement (e.g. in pole X), that is to say in the case of an undeflected rest position, the magnet arrangement 10 theoretically sits at a dead point from which it can no longer deflect, since at this point the magnetic force balance prevails. In practice, however, it should not be assumed that a complete force balance actually occurs in the rest position. Accordingly, it should be expected that the magnet arrangement 10 can be deflected again from the dead point by a strong current pulse in one or both

coils

15, 16, and the plunger coil actuator 1 can then be used normally. As an alternative, however, it is also possible to provide electrical and/or magnetic means (not shown) in order to avoid that the first coil 15 and the magnet arrangement 10 adopt a relative position with respect to each other which results in a magnetic force balance. As an alternative or in addition, the component can also be designed such that the magnet arrangement 10 can thus be deflected from the dead point.

Claims

1. A plunger coil actuator (1) comprising at least a first coil (15) and a second coil (16) and a magnet arrangement (10), wherein the coils (15, 16) interact with the magnet arrangement (10)For enabling deflection of the magnet arrangement (10) within a movement region (17), wherein a central axis (M) of the magnet arrangement (10) is located when the magnet arrangement (10) is in a rest position not deflected by the coils (15, 16)₃) -a pole (X) of a polar coordinate system passing through a moving area (17), characterized in that the first coil (15) is arranged and designed such that the pole (X) of the polar coordinate system is located within a circumference (18) of the first coil (15) and the first coil (15) exerts an outwardly oriented radial force on the magnet arrangement (10), and wherein the second coil (16) is arranged and designed such that a tangential force is exerted on the magnet arrangement (10).

2. Plunger coil actuator (1) according to claim 1, characterized in that the central axis (M) of the first coil (15)₁) The pole (X) of the polar coordinate system passing through the moving region (17) extends or is adjacent to the pole (X) of the polar coordinate system of the moving region (17).

3. Plunger coil actuator (1) according to claim 1 or 2, characterized in that the first coil (15) is designed and/or arranged such that a central axis (M) of the magnet arrangement (10) is deflected by the first coil (15) when the magnet arrangement (10) is deflected by the first coil (15)₃) Extends within the circumference (18) of the first coil (15).

4. Plunger coil actuator (1) according to claim 1, 2 or 3, characterized in that the coils (15, 16) and the magnet arrangement (10) are arranged and/or designed such that the radial force applied by the first coil (15) to the magnet arrangement (10) results in a movement of the magnet arrangement (10) along a radial coordinate (r) of the polar coordinate system, and in that the tangential force applied by the second coil (16) to the magnet arrangement (10) results in an angular coordinate of the magnet arrangement (10) along the polar coordinate system

Is moved.

5. Plunger coil actuator (1) according to one of claims 1 to 4, characterized in that the first coil (15) is designed as a spiral-shaped flat coil and/or the second coil (16) is designed as a ring coil.

6. Plunger coil actuator (1) according to any of claims 1 to 5, characterized in that the magnet arrangement (10) has a magnetization direction extending orthogonally to the movement region (17).

7. Plunger coil actuator (1) according to any of claims 1 to 6, characterized in that the first coil (15) is arranged closer to the magnet arrangement (10) than the second coil (16).

8. Plunger coil actuator (1) according to any of claims 1 to 7, characterized in that the central axis (M) of the first coil (15)₁) And a central axis (M) of the second coil (16)₂) And/or a central axis (M) of the magnet arrangement (10)₃) Extending coaxially.

9. Plunger coil actuator (1) according to any of claims 1 to 8, characterized in that at least one iron core (21) concentrating the magnetic flux is arranged in the first coil (15) and/or in the second coil (16).

10. Plunger coil actuator (1) according to one of claims 1 to 9, characterized in that a control and/or adjustment unit (24) is provided in order to control or adjust the deflection of the magnet arrangement (10).

11. Plunger coil actuator (1) according to any of claims 1 to 10, characterized in that an electrical and/or magnetic member is provided in order to avoid that the first coil (15) and the magnet arrangement (10) adopt a relative position with respect to each other that results in a magnetic force balance such that the first coil (15) cannot apply any outwardly oriented radial force to the magnet arrangement (10) and/or in order to deflect the magnet arrangement (10) from such a relative position.

12. Plunger coil actuator (1) according to any of claims 1 to 11, characterized in that the magnet arrangement (10) has at least one permanent magnet (22).

13. Plunger coil actuator (1) according to claim 12, characterized in that the at least one permanent magnet (22) has a magnetization such that a pole boundary (22a) between two poles (22b, 22c) of the permanent magnet (22) has a curved profile.

14. Projection exposure apparatus (100, 400) for semiconductor lithography, having an illumination system (103, 401) with a radiation source (402) and an optical unit (107, 403) having at least one optical element (415, 416, 418, 419, 420, 108) which can be adjusted and/or manipulated and/or deformed by a plunger coil actuator (1) according to one of claims 1 to 13.

15. The projection exposure apparatus (100, 400) according to claim 14, at least one of the optical elements (415, 416, 418, 419, 420, 108) is designed as a facet mirror (415), wherein the facet mirror (415) has a carrier structure and a plurality of individually adjustable mirror facets (2) carried thereby, wherein each mirror facet (2) is connected to the carrying structure via a flexure (5), so that the mirror facets (2) can be tilted about two axes orthogonal to each other, wherein the mirror facet (2) is rigidly connected to an actuating rod (8), and wherein the actuating rod (8) is deflectable by a plunger coil actuator (1) according to one of claims 1 to 13, so as to tilt the mirror facet (2) about at least one of the two axes.