DE102018207454A1 - Actuator assembly, projection exposure system and wafer inspection system for semiconductor lithography - Google Patents

Abstract

The invention relates to an actuator assembly (1) comprising an optical element (2) held by a retaining element (8), a supporting structure (6) and actuators (4) adapted to force the retaining element (8) and / or can exert moments, wherein the holding element (8) is arranged such that the forces exerted by the actuators (4) and / or moments cause deformation of the holding element (8) and thus deformations of the optical element (2). Furthermore, the invention relates to a projection exposure system and a wafer inspection system with an actuator assembly.

Description

The invention relates to an actuator arrangement for the deformation of optical elements and to a projection exposure apparatus equipped with the actuator arrangement for semiconductor lithography and a wafer inspection installation.

Actuator assemblies for deforming optical elements are known in the art. The actuator assemblies are used, for example, in projection exposure systems for the semiconductor industry and in systems for wafer and / or mask inspection, whereby the systems for wafer inspection and mask inspection can be operated automatically and not automatically. The optical components used for imaging for the applications described above, which may be in particular lenses and mirrors, must be positioned and / or deformed with the highest precision in order to be able to ensure the required imaging quality.

From the DE 193 27 603 A1 An actuator arrangement is known. The actuator arrangement has an optical element, which is held in a socket. The socket is connected at its periphery at two diametrically opposite locations fixed to a frame, wherein the connection is made stiff in the direction of the optical axis. Also disposed diametrically opposite are two actuators which are arranged to effect non-rotationally symmetric and non-radial forces and / or moments on the optical element to produce deflections substantially without changes in thickness. The disadvantage of this solution is that the optical element is held in position by the joints during deformation and thus can not be displaced in addition to the deformation in order to further increase the imaging quality. Systems of the latest generation, with fewer and fewer optical elements and ever higher imaging quality requirements, require actuator arrangements that both deform optical elements and permit solid state shifts of the optical element.

The object of the present invention is to provide an actuator arrangement which enables a deformation and a displacement and / or tilting of an optical element. Another object of the invention is to provide a projection exposure apparatus for semiconductor lithography and a wafer inspection system with improved possibilities for the correction of aberrations.

This object is achieved by a device having the features of independent claim 1. The subclaims relate to advantageous developments and variants of the invention.

The invention includes an actuator assembly comprising an optical element held by a retaining element. The actuator assembly further comprises actuators which are adapted to exert forces and / or torques on the retaining element, wherein the retaining element is set up such that the forces exerted by the actuators and / or moments deformations of the retaining element and thus deformations of the optical Element can effect. Such an actuator assembly is often referred to as a manipulator or manipulator unit. The optical element is often designed as a rotationally symmetrical component and is connected to the holding element, which may be designed in the form of a socket with several support points. However, the holding element and the optical element can also be embodied in one piece in order, for example, to avoid deformations due to different coefficients of thermal expansion of the optical element and socket. A one-piece design of optical element and holding element is preferably used in mirrors.

In particular, eight actuators can act on the mount, which can be arranged, for example, at equal angular intervals on the circumference of the mount and are supported on the support structure, which can form the outer mount of the actuator arrangement. The outer frame can also be connected to the outer sockets of other optical elements to form a lens. The outer sockets are in the prior art, especially in systems where predominantly lenses are installed, formed mainly circular, whereby the assembly of the twisting of the optical elements for correcting aberrations is simplified. All actuators can be constructed identically, which has an advantageous effect in the production and storage of the actuators.

In one embodiment of the invention, the actuators may be arranged so that tangential single-wave, two-wave, three-wave, four-wave and radial single-wave can be impressed in the optical element. Radial waviness in the present case is related to the number of moments that can be introduced into the optical element. By the arrangement of Actuators on the edge of the optical element can bring this only a carding moment at the edge of the optical element in the direction of the optical axis, wherein a positive moment can roll the edge of the optical element up and a negative moment the edge of the optical element down. In connection with the tangential ripples applies that at a zero crossing of the tangential ripple and the radial single ripple changes the sign, so a positive moment passes into a negative moment and vice versa. Tangential wavinesses are synonymous with translational solid state shifts, ie a displacement of the optical element along the optical axis or a tilting of the plane of the optical element about an axis perpendicular to the optical axis.

The optical axis is the axis of symmetry of a rotationally symmetric optical system, whereby the symmetry of the surfaces and not the symmetry of the border is decisive. Deformations and displacements of optical elements are usually related to the optical axis.

In optics and in the semiconductor industry, the ripples are also often described as Zernike, which corresponds to a numbering of the Zernike polynomials of different order. Zernike polynomials are orthogonal polynomials describing wavefronts composed of the product of a radius-dependent part, ie a radial component, and an angle-dependent part, ie a tangential component. For example, Z2 and Z3 are a tilt of the plane about two orthogonal axes. The number of required for the adjustment of the deformations actuators is given in the tangential ripples by the order of the ripple, the tangential ripples always have 2 orientations that are orthogonal to each other, such as Z5 and Z6 for the two-wave tangential ripple, with a Angle of 45 ° to each other are twisted. The number of actuators in the table below applies to a tangential ripple in one orientation, the number in the bracket is the number of actuators necessary to realize the tangential ripples in both orthogonal orientations.

In the case of radial waviness, FEM simulations have shown that a moment has to be introduced at least at eight points of attack in order to be able to set the radial single-ripples without significant tangential ripples. This is because for the initiation of moments 2 Actuators are required per point of attack, as will be explained in more detail below. A point of attack is the point on the circumference of the holding element, on which the actuator transmits the force to the holding element. Its position is not defined by a radius, but by an angle. The force of the actuators is transmitted at the connection point to the holding element and the support structure. In the case of moments are 2 Actuators arranged at a point of application, wherein the connection points have a radial offset. As a result, the two actuators can apply a moment about the tangent through the point which lies radially between the two connection points of the actuators.

The table shows the deformations in Zernike adjustable by the actuator arrangement described in the invention. Zernike number description Number of actuators Z2 / Z3 Tilt around two orthogonal axes (= tangential single-waviness) 3 Z4 Focus (= radial ripple) 16 Z5 / Z6 Astigmatism (= tangential two-waviness) 4 (8) Z7 / Z8 Coma (= combination of radial single-waviness and tangential single-waviness) 16 Z10 / Z11 Three-ripples (= tangential trinucleation, axes rotated by 30 ° with respect to each other) 6 (8) Z12 / Z13 Higher order astigmatism (= combination of radial single-ripples and tangential double-ripples) 16 Z17 (or Z18) Quadrature (= tangential quadrature, axes rotated by 22.5 °) 8th Z19 / Z20 Higher order tristimulus (= combination of radial single ripple and tangential tristimulus) 16

The actuators are advantageously arranged so that in each case an actuator is arranged on the minima and maxima of the respective tangential ripples. Experiments have shown that the ripples can be set even when the points of application of the actuators are not directly to the minima and maxima of the respective ripples, as is the case for example in the tangential tristimulus.

In a further embodiment, at least one actuator of the actuator arrangement in the middle of the bending line of the optical element can engage the holding element. Each offset of the force application point of the actuator to the center of the bending line of the optical element leads to moments and thereby shear and compressive stress in the optical material, which lead to unwanted optical effects, such as stress birefringence, and by the load of the optical material, the size of the possible Deformation of the optical element can reduce.

In one embodiment of the invention, an individual force can be set on each actuator. All manufactured components are subject to manufacturing and - material fluctuations that may affect the transmission of the forces from the actuator to the holding element and from the holding element further on the optical element. Actuators in which the force acting on the holding member is individually adjustable, have the advantage of being able to compensate for the above influences, for example, if a calibration of the deformations on the optical element in relation to the force supplied by the actuator is performed and this example in a Table is deposited.

In a further embodiment of the invention, a control unit may be present, which may comprise a measuring system for measuring the deformation of the optical element and a controller for calculating the actuator force and / or the Aktuatorverfahrweges and which may be connected to at least one actuator. The regulation and / or control can set the force and / or travel required on the actuator for a specific deformation of the optical element. Force actuators such as Lorentz motors can be used as well as a simple spindle drive, in which the path can be converted, for example via a spring in a force on the holding element, the spring may be configured for example as a compression spring. In addition to the combination of spindle drive and pressure spring, any other type of suitable actuators, such as piezo-hybrid drives, stepper motors, worm drives, piezo stacks or air or water bellows for the deformation of the holding element can be used.

In a further embodiment of the invention, at least one actuator can be controlled by the control unit in a semi-active operating mode. In a further embodiment of the invention, at least one actuator can be controlled by the control unit in an active operating mode. The optical system actuator assemblies described herein can correct the aberrations remaining in the mounted state of the optical system after fabrication and assembly of the system. Due to the different requirements on the duration of a correction of aberrations is distinguished between semi-active and active actuator arrangements, wherein a semi-active actuator assembly controlled by a predetermined target position or regulated anfährt and the control unit is then turned off again. A semi-active actuator arrangement therefore preferably has a self-locking drive or the force or the position of the actuator can be frozen after reaching the predetermined desired position, for example by a locking element. An active actuator assembly, however, controls their current setpoint position in a closed loop and is always active during operation, the actuators must have a corresponding design with respect to Verstellzyklen, which is given for example in piezo drives. During operation of the optical system in a lithography system, a wafer inspection system or another machine of semiconductor technology, changes in the optical system may occur, such as aging of the material, contamination of the optical elements or heating of the optical system by the useful radiation. The cycles in which the corrections described above are carried out have different lengths and therefore also take place at different times. The adjustment after the construction of the optical system becomes carried out once and has the duration of the setting only small time restrictions. Corrections that are necessary due to slow life-time aberrations only have to occur every few weeks, months, or years and can be scheduled as part of other machine maintenance, and therefore do not impose any high demands on the duration of the adjustment the actuators. Corrections for errors that occur during operation and directly and significantly negatively affect the image quality must often also be corrected during operation

In one embodiment of the invention, the control unit can be configured so that eigenmodes of the holding element and the optical element can be damped by controlling the actuators. By excitation from outside or other subsystems in the semiconductor technology machine in which the actuator assembly is installed, such as the wafer stages in a lithographic machine, the optical elements can be excited and oscillate in their own modes. By a suitable arrangement of the actuators and suitable measuring systems, the suggestions of the eigenmodes can be damped by the actuators.

In a further embodiment, a connecting element between the holding element and the support structure may be arranged. In addition to the actuators, the connecting element connects the retaining element to the supporting structure in order to advantageously stiffen the connection between the retaining element and the supporting structure.

In a further embodiment of the invention, at least one additional connecting element between the holding element and the support structure is designed as a leaf spring. The connection of the actuators is usually designed stiff only in the effective direction of the actuators. The leaf spring is stiff in its width and length, whereas it is soft perpendicular to the width and length and in rotation about the longitudinal or transverse axis of the leaf spring. If the leaf springs are arranged in the direction of their longitudinal extension perpendicular to the direction of action of the actuators, the holding element can be rigidly connected to the support structure in all six degrees of freedom, with the stiffnesses of the actuator and the leaf springs complementing each other.

In this context, soft is intended to mean that the rigidity of the connection and / or connection is designed as low as possible in the context of the design and the technical properties of the material used, such as, for example, yield strengths or bending fatigue strengths. In contrast, stiffness is to be understood as the greatest possible rigidity within the framework of the design and the technical properties of the material used.

The connection of the actuators may for example contain a universal joint, which may be performed, for example, in the form of two twisted by 90 ° to each other arranged leaf springs, which has the advantage that the universal joint works without play. The leaf springs can be detachably connected to the support structure and the holding element, such as by a screw, but also a one-piece solution of support structure, retaining element and leaf spring is conceivable.

In a further embodiment of the invention, the connecting elements and the actuators can be arranged in pairs circumferentially at the same points of attack of the holding element and the support structure. Due to the arrangement of the connecting elements and the actuators at the same point of the retaining element and the support structure of the power flow of the parasitic forces introduced by the actuators extends directly from the connection point of the actuators to the connection point of the connecting elements and not by the holding element, which parasitic deformations of the holding element and connected thereto optical element can be avoided.

In a further alternative embodiment of the invention, the connecting elements can be arranged circumferentially between the points of application of the actuator on the holding element and the support structure. In the case of a deformation of the holding element by the actuators, wherein the actuators are advantageously at the maxima and minima of the set ripple, the relative movement of the points of application of the actuators on the deformed holding element and the very stiff and therefore minimally deformed support structure is greatest. Due to the arrangement of the connecting elements between the points of application of the actuators, the connecting elements are not located at the location of the maximum deflection and are less heavily loaded, as in an arrangement at the point of application of the actuators. Which of the two arrangements is the best for the actuator assembly, is due to the required for the use ratio of deformation and displacement of the holding element.

In a further embodiment of the invention, the effective direction of the actuators can be aligned parallel to the optical axis. This arrangement has the advantage that the connection of the actuator to the holding element in the effective direction of the actuators and perpendicular thereto can be made very stiff, since no or only minimal parasitic movements occur perpendicular to the direction of movement of the actuators. As a result, can be dispensed with the connecting elements, whereby the structure is advantageously simplified.

In a further embodiment of the invention, the effective directions of the actuators can not be aligned parallel to the optical axis. Actuator arrangements for moving optical elements in the direction of the optical axis usually have their direction of action in the direction of the optical axis. In an exemplary arrangement of 8 actuators, which are arranged at equal intervals on the circumference of the holding element and the support structure, both of which can be performed in an annular manner around the optical element, and their direction of action parallel to the optical axis of the system and thus the lens act, a Displacement in the direction of the optical axis and a tilt about each axis perpendicular to the optical axis can be realized. If the degrees of freedom displacement with respect to the optical axis and rotation or tilting about the optical axis are to be controlled with a plurality of actuators, the effective direction of the actuators must also have components in these degrees of freedom in order to be able to carry out this control.

In a further embodiment, the directions of action of the actuators with respect to the support structure can be tilted in the tangential direction. The support structure of the actuator assembly, like the optical element and the holding element, can often be circular in shape and surrounds the optical element and the holding element in the form of a ring. The tilting of the direction of action of the actuators in the tangential direction of the support structure has the advantage that the actuator assembly in the radial direction of the support structure requires a minimum of space. As a result of the arrangement of the actuators in the tangential direction, the retaining element can additionally be displaced in a plane perpendicular to the optical axis and / or rotated about the optical axis.

In one embodiment of the invention, the effective directions of each two adjacent actuators can be tilted at the same angle to each other, which simplifies the control of the actuators, since the calculation of the movements is simplified by the symmetrical arrangement of the actuators.

In a further embodiment, the forces and / or moments of the actuator can be transmitted to the holding element via a lever. By the lever, which is connected to the support structure with a hinge, a translation of the force of the actuator can be realized and the actuator can be arranged radially outward, ie further away from the optical axis. This has the advantage that no installation space for a direct connection of the actuator to the holding element must be provided, which is often severely limited by adjacent holding elements and optical elements.

In one embodiment of the invention, the lever and the retaining element can be connected to one another via a wire. The wire can transmit movements and / or forces only along its longitudinal extent, so that parasitic movements and / or forces can not be transmitted from the lever or only in a greatly attenuated form to the holding element. Furthermore, the wire can be attached to the lever and the holding element either so that it can transmit compressive forces and tensile forces. If the wire is firmly connected only to the support structure or the holding element, the wire can only transmit compressive forces, since with tensile forces the wire would lift off at the location where it is not firmly connected to the support structure or the holding element. Advantageously, the wire is pressed by a force such as a spring against the non-fixed contact point to prevent lifting of the wire from the holding element in reducing the pressure force by the actuator.

In a further embodiment of the invention may be arranged between the actuator and the lever, a first spring, wherein the bias of the first spring may be adjustable. The arranged between the actuator and the lever spring on the one hand converts the path of the actuator into a force, on the other hand, by the first spring and a counterforce on the actuator exerted, for example, in a spindle drive, the backlash of the spindle largely minimize or completely avoided.

In a further embodiment, a second spring may be arranged between the holding element and the support structure, wherein the bias of the second spring may be adjustable. The second spring between the support member and the support structure compensates for the force of the bias of the actuator, so the force of the spring between the actuator and the lever to a deformation of the holding element and thus minimizing the optical element and thus a deformation-free position, hereinafter also referred to as zero position, to enable the actuator assembly. Due to the adjustability of the second spring, the force acting on the inner ring can be adjusted individually and so individually adjusted at each point of the retaining element. In addition, by the two springs between the actuator and the lever and between the holding element and support structure and possible differences in the stiffness and geometry of the inner ring and / or the springs themselves can be compensated.

In a further alternative embodiment of the invention may be present in the support structure, a fluid-filled cavity with chambers which are closed with a membrane. The chambers are arranged at the locations where a lever acts on the retaining element via a force transmission element and the membranes contact the retaining element on the side opposite the point of application of the force transmission element. The chambers may be interconnected via a connection channel and together with the connection channel form a fluid-filled cavity. The fluid may be a gas such as air or a liquid such as water or oil. The arrangement of the chambers replaces the springs between the support member and the support structure. In the zero position (no deformation of the retaining element) all actuators press with the same force on the retaining element on the membranes. When adjusting a deformation, such as a two-waviness, also referred to as astigmatism, the force is increased at two diametrically opposed actuators and reduced at two other diametrically opposed actuators and the actuators between the actuators with increased force and the actuators with reduced Force adjusted to values that support the astigmatism of the holding element. Increasing the force on a membrane of a chamber results in a reduction of the volume in that chamber, reducing the force on a membrane of a chamber increases the volume of the chamber. By the connection of the chambers with each other and the symmetrical distribution of force increase and force reduction in the chambers, the fluid from the chambers with a smaller volume in the chambers with increased volume flow and thus create a balance at the same pressure. An advantage of this solution is a higher rigidity due to smaller space in the holding element compared to the adjustable springs and by the pressurized fluid and a lower risk of displacement of the entire optical element along its optical axis by the compensation of the forces on the holding member by the fluid.

In another embodiment, the invention may include a semiconductor lithographic projection exposure apparatus having an actuator assembly according to any of the embodiments described above. In projection exposure systems, the operation itself and long-term effects in the optical material, such as compaction, cause aberrations in the wavefront, which have a decisive influence on the imaging of the reticle on the wafer. By using an actuator arrangement according to one of the embodiments described above, the aberrations can be corrected and thus advantageously improve the imaging of the reticle onto the wafer.

In a further embodiment, the invention may include a wafer inspection system for semiconductor lithography with an actuator assembly according to one of the embodiments described above. In wafer inspection systems, the operation itself and long-term effects in the optical material, such as compaction, cause aberrations in the wavefront, which have a decisive influence on the imaging of the wafer. By using an actuator assembly according to any of the embodiments described above, the aberrations can be corrected and thus advantageously improve the imaging of the wafer.

• 1a eine exemplarische Darstellung einer Aktuatoranordnung aus dem Stand der Technik,
• 1b eine exemplarische Darstellung einer Aktuatoranordnung aus dem Stand der Technik,
• 1c eine exemplarische Darstellung einer Aktuatoranordnung aus dem Stand der Technik,
• 2a eine schematische Darstellung einer Aktuatoranordnung aus der Erfindung,
• 2b eine weitere schematische Darstellung einer Aktuatoranordnung aus der Erfindung,
• 3a eine schematische Schnittdarstellung einer ersten Ausführungsform der Erfindung,
• 3b eine schematische Schnittdarstellung einer zweiten Ausführungsform der Erfindung,
• 3c eine schematische Schnittdarstellung einer dritten Ausführungsform der Erfindung,
• 4a eine schematische Schnittdarstellung einer vierten Ausführungsform der Erfindung,
• 4b eine schematische Detailansicht einer vierten Ausführungsform der Erfindung,
• 5 eine schematische Ansicht einer erfindungsgemäßen Anordnung,
• 6 eine Projektionsbelichtungsanlage für die Halbleiterlithographie, in der die Erfindung zur Anwendung kommen kann, und
• 7 eine Waferinspektionsanlage für die Halbleiterlithographie, in der die Erfindung zur Anwendung kommen kann.

Hereinafter, embodiments and variants of the invention will be explained in more detail with reference to the drawing. Show it

• 1a an exemplary representation of an actuator assembly of the prior art,
• 1b an exemplary representation of an actuator assembly of the prior art,
• 1c an exemplary representation of an actuator assembly of the prior art,
• 2a a schematic representation of an actuator assembly of the invention,
• 2 B a further schematic representation of an actuator assembly of the invention,
• 3a a schematic sectional view of a first embodiment of the invention,
• 3b a schematic sectional view of a second embodiment of the invention,
• 3c a schematic sectional view of a third embodiment of the invention,
• 4a a schematic sectional view of a fourth embodiment of the invention,
• 4b a schematic detail view of a fourth embodiment of the invention,
• 5 a schematic view of an arrangement according to the invention,
• 6 a projection exposure apparatus for semiconductor lithography, in which the invention can be used, and
• 7 a wafer inspection system for semiconductor lithography, in which the invention can be used.

1 shows an example of an actuator arrangement 1 from the prior art in a simplified schematic representation, being omitted for ease of understanding on a holding element and a support structure and only an optical element 2 , Bearings 3 and actuators 4 are shown. The bearings 3 of the optical element 2 are offset by 180 ° diametrically on the circumference of the optical element 2 arranged, so are opposite each other. The two bearings 3 define an axis, hereafter referred to as X -Axis is called. The actuators 3 lie to the bearings 3 each offset by 90 ° also on the circumference of the optical element 2 and also form an axis perpendicular to X -Axis lies and below as Y -Axis is called. The X Axis and the Y -Axis span an orthogonal coordinate system, wherein the Z -Axis is directed in the sheet plane and at the same time the optical axis of the optical element 2 represents. By controlling the two illustrated actuators 4 with a control unit, not shown, wherein the actuators 4 act in the same direction, for example in the direction of Z -Axis, becomes the optical element 2 Tangentially twisted two-wave, so assumes an astigmatic shape. A disadvantage of this solution is that the center of the optical element 2 through the fixed bearings 3 in the direction of Z -Axis is also displaced in addition to the deformation, which also leads to an optical effect of the optical element 2 leads. The above-mentioned control unit includes sensors for detecting the deformation of the optical element 2 and optional additional sensors that control the position of the actuators 4 can capture and is designed so that they are the deformation and solid state movements of the optical element 2 can control and regulate.

1b shows an actuator assembly 1 that are essentially identical to the one in 1a shown actuator assembly 1 is constructed, with the difference that the bearings 3 and the actuators 4 at 45 ° around the Z -Axis are arranged rotated. In the process of actuators 4 will be in the optical element 2 also form a tangential two-wave deformation.

1c shows a combination of the two in 1a and 1b shown actuator arrangements 1 on an optical element 2 , The bearings 3 lie in pairs opposite and rotated by 45 ° to each other and the actuators 4 rotated by 90 ° to the bearings 3 , With the in 1c shown actuator assembly 1 From the prior art, it is possible, any orientation of a tangential two-wave deformation in the optical element 2 inculcate, this always with a shift of the center of the optical element 2 in the direction of Z Axis goes along.

2a shows an example of an actuator assembly according to the invention 1 in a simplified schematic representation, was omitted for clarity on the representation of a retaining ring and a support structure and only an optical element 2 , Bearings 3 and actuators 4 are shown. In this exemplary illustration of the invention are eight actuators 4 at equal angular intervals on the circumference of the optical element 2 arranged, wherein the actuator assembly 1 has no bearings. Due to the symmetrical arrangement of the actuators 4 there are always two actuators 4 opposite and form an axis passing through the center of the optical element 2 goes. By the in 2a shown actuator assembly 1 can be adjusted by a control unit, not shown, a tangential two-wave, three-wave and four-wave deformation. The size of the deformations of the retaining element 8th can be between 100 nm and 500 μm. In a preferred embodiment, the size of the deformation of the retaining element 8th lie between 400 and 450 nm The four-wave deformation can be adjusted only in the orientation in which the attack points of the actuators 4 are at the maxima and minima of the four-wave deformation. The adjustable deformations correspond to the known in semiconductor lithography Zernikes Z5 and Z6 which represent an astigmatism, the Zernikes Z10 and Z11 , which denote a tangential tristimulus and Z17 , which denotes an orientation of the tangential quadrature. Besides the deformations it is due to the eight actuators 4 also possible, a tilt of the optical element 2 around each axis, perpendicular to the Z Axis stands and a shift along the Z To adjust the axis.

2 B shows a further embodiment of the invention in a likewise schematic representation, which is opposite to the actuator assembly 1 the 2a this differs in that next to each actuator 4 in radial from the Z -Axis remote location another actuator 4 ' is arranged so that at the points of application of the actuators 4 on the optical element 2 not just forces in the direction of Z -Axis can be introduced, but also moments around the tangent of the point of the actuator pair 5 on the optical element 2 , As a result, in addition to those with the actuator assembly 1 out 2a possible tangential deformations also adjust radial deformations, which in combination with the tangential deformations further Zernikes, such as Z4 which is also referred to as focus, Z7 / Z8 which is also called a coma Z12 / 13 and Z20 / 21 result. Compared to the state of the art, as in the 1a to 1c described, can with the in 2 B illustrated actuator assembly 1 a large number of tangential deformations, radial deformations and combinations of the radial and tangential deformations of the optical element 2 will be realized. In addition, the optical element 2 still in the direction of Z -Axis and moved to any Z -Axis vertical axis as a solid, so without deformation, be tilted.

3a shows in a sectional view an embodiment of the invention in which various tangential deformations in an optical element 2 can be embossed, wherein the optical element 2 the actuator assembly 1 in the embodiment shown by way of example as a lens 2 is executed. The deformation of the optical element 2 is due to the deformation of a holding element 8th through actuators 4 achieved, wherein the actuator 4 over a lever 11 with the holding element 8th connected is. The optical element 2 is via a decoupling element 9 with the holding element 8th connected. The decoupling element 9 takes the optical element 2 stress-free, so without deformation of the optical element 2 and decouples it against disturbances, such as, for example, stresses due to different thermal expansion coefficients between the optical element 2 and the holding element 8th , By the decoupling element 9 becomes the deformation of the holding element 8th with a fixed gear ratio to the optical element 2 transfer. The gear ratio can range from 1: 1 to 10: 1. In a preferred embodiment, the ratio is 3: 1. The decoupling element 9 also decouples tangential moments on the retaining element 8th leading to an unwanted very local deformation of the optical element 2 would lead. Alternatively, several decoupling elements 9 between holding element 8th and optical element 2 to be ordered. The actuator 4 is in the in 3a shown embodiment of the invention as a stepper motor 4 executed and in the support structure 6 attached. The actuator 4 acts in the direction of Z -Axis perpendicular to the optical surface of the optical element 2 stands, on a lever 11 , Between the lever 11 and the actuator 4 is a first compression spring 13 attached, indicating the movement of the actuator 4 converted into a force. The first compression spring 13 has in addition to the transformation of the movement of the actuator 4 in a force in addition the task, the backlash of the spindle of the actuator 4 by applying a force to the spindle of the actuator 4 to minimize. The lever 11 is about a joint 12 on the supporting structure 6 stored and allowed the lever 11 a rotation around the tangent of the joint 12 of the lever 11 on the supporting structure 6 , The lever 11 is stiff and transmits the force to a first side of a power transmission element 10 such as a wire 10 on its other side with the retaining element 8th connected is. The wire 10 transmits the force in its longitudinal extent and has in all other degrees of freedom a decoupling effect, so that almost no moments on the holding element 8th can be transmitted, leading to unwanted deformations of the retaining element 8th and the optical element 2 would lead. On the connection point of the wire 10 opposite side of the holding element 8th is a second compression spring 13 ' arranged, which is a counterforce to the first compression spring 13 between actuator 4 and levers 11 applies. Both compression springs 13 . 13 ' are each about a jack 14 . 14 ' , on the one hand a bore, which is the compression spring 13 . 13 ' receives and on the opposite side a geometry, such as two holes, for receiving a tool for adjusting the depth of engagement of the socket 14 . 14 ' and thus the bias of the compression spring 13 . 13 ' , having. The socket 14 ' for the second compression spring 13 ' is over an external thread in another ring 15 stored, in turn, with the support structure 6 is connected and as an abutment 15 for the compression spring 13 ' serves. The second compression spring 13 ' on the holding element 8th is via the socket 14 ' adjusted so that the retaining element 8th , like in the 3a shown, has no deformations. The holding element 8th is through the connection via the actuators 4 to the support structure 6 only in the direction of Z -Axis stiff and soft in all other directions. The holding element 8th is therefore additionally with leaf springs 7 to the support structure 6 tethered. The leaf springs bind the retaining element 8th in the XY Plane, ie the plane perpendicular to the optical axis of the optical element 2 , stiff, with deformations of the retaining element 8th in the direction of Z Axis are still possible. This is the retaining element 8th in the degrees of freedom that are not or only in a very small area to be adjusted stiff and connected with respect to the degrees of freedom to be adjusted and the deformations of the holding element soft tailed. In the in 3a illustrated embodiment, the support structure 6 , the retaining element 8th and the leaf springs 7 together monolithic, so one piece, executed, what a good orientation of the retaining element 8th and the support structure 6 to each other and by identical material properties a slight deviation in the mechanical properties of the leaf springs 7 entails. The leaf springs 7 are circumferentially at the same locations on the circumference of the support structure 6 and the holding element 8th Tailed like the actuators 4 to the flow of force from parasitic forces of the holding element 8th directly into the supporting structure 6 to conduct and thereby parasitic deformations of the retaining element 8th and thus the optical element 2 to minimize. In the in 3a illustrated actuator assembly 1 can be attached to any actuator 4 an individual force can be adjusted, whereby a power transmission to the holding element 8th with minimal parasitic disturbances can be ensured and so a deformation of the optical element 2 is achieved in the desired shape without further unwanted deformations in the optical element 2 memorize. Due to the pressure spring 13 induced conversion of the feed of the actuator 4 , So the distance covered, in a force, the introduced force and thus the deformation of the holding element 8th can be set advantageously in smaller increments. The compression spring 13 acts here as an additional translation element whose translation is dependent on the spring stiffness.

In the 3b shown second embodiment of the invention is identical in construction to that in the 3a shown first embodiment of the invention with the exception of in 3a shown compression springs 13 ' between holding element 8th and ring 15 , The compression springs 13 ' and the jacks 14 ' from Fig, 3a, each actuator 4 are assigned in 3b through chambers 18 that with a membrane 19 in the direction of the retaining element 8th are closed and where the membranes 19 with the holding element 8th in contact and via a connection channel 20 connected to each other, in turn, with a lid 21 is closed, replaced. The chambers 18 , the membranes 19 and the connection channel 20 with the lid 21 together form a cavity 17 in the counter bearing 15 which is a fluid filled closed system. In the neutral position of the actuator assembly 1 , ie in the position in which the holding element 8th is not deformed, the chambers are 18 all approximately the same size. Due to the deflection of the actuators 4 the volume is in a part of the chambers 18 over the membrane 19 reduced, whereas the volume in another part of the chambers 18 is enlarged. Through the connection channel 20 gets the fluid from the chambers 18 with reduced volume in the chambers 18 moved with increased volume. Due to the symmetrical deflection of the actuators 4 and the closed system keeps the volume in the cavity 17 always identical and will only be between the chambers 18 postponed. The fluid in the cavity 17 is under pressure to the for the neutral position of the holding element 8th necessary counterforce to the first compression springs 13 between actuator 4 and levers 11 to ensure. The incompressible fluid leads to an additional stiffness in the connection of the actuator 4 and the holding element 8th to the counter bearing 15 and thus also the actuator assembly 1 be made stiffer than in the 3a illustrated first embodiment of the invention.

In the 3c illustrated third embodiment of the invention has at least one additional second actuator 4 ' at a point of application of the retaining element 8th which extends radially outward from the in 3a and 3b illustrated actuator 4 on the supporting structure 6 is connected. The connection of the actuator 4 ' to the support structure 6 and the holding element 8th is identical to the one in 3a shown connection and will therefore not be described again at this point. The second actuator 4 ' is compared to the first actuator 4 rotated by 180 ° on the support structure 6 attached and the force application point of the wire 10 has a radial offset to the force application point of the first actuator 4 , by which a moment on the retaining element 8th can be initiated. The wire 10 of the second actuator 4 ' This is due to an opening in the counter bearing 15 guided. The wire 10 is fixed in the illustrated embodiment with the lever 11 and the holding element 8th connected and can thereby apply pressure and tensile forces. The compression spring 13 The task has the bias to avoid the backlash in the actuator 4 to provide and the compression spring 13 ' has the task of a deformation-free neutral position of the holding element 8th Adjust and adjust by the deflection of the actuator 4 generated restoring forces of the compression springs 13 . 13 ' only support the actuator.
In another embodiment, not shown, the connection of the wire 10 on the holding element 8th only via the contact pressure of the compression springs 13 .
13 'be made, so the wire 10 can only transmit compressive forces. In this embodiment of the invention, the compression springs have 13 . 13 ' the task of reducing the pressure force through the wire 10 on the holding element 8th make sure the wire 10 and the holding element 8th always stay in touch. The actuator arrangements 1 in the 3a - 3c are in connection with a control unit, not shown, particularly suitable for use as semi-active manipulators, since as actuators 4 used stepper motors 4 self-locking are formed.

• - Translation in X-, Y- und Z-Richtung, wobei die Z-Richtung die Hauptrichtung ist
• - Z5, Z6, Z10, Z11 und Z17

Die Translationen in X-Richtung und Y-Richtung können nur dann realisiert werden, wenn die Aktuatoren 4, wie in 4a dargestellt, mit einem Anstellwinkel 23 gegenüber der Z-Achse, also der optischen Achse des Spiegels 2 ausgerichtet sind, da nur dann die Wirkrichtung des Aktuators 4 eine Komponente in X- und Y-Richtung enthält. Die Aktuatoren 4 sind jeweils tangential zu ihren Anbindungspunkten in der Tragstruktur 6 angestellt und jeweils zwei Aktuatoren 4 sind zueinander gekippt. Die tangentiale Kippung der Aktuatoren 4 hat den Vorteil, dass der benötigte radiale Bauraum minimiert wird, wobei jede andere Kippung aus der Z-Achse heraus zu dem gleichen Resultat führt. Die Z-Richtung ist die Hauptrichtung, in der das in 4a dargestellte optische Element 2 verfahren werden soll, wodurch der Anstellwinkel 23 gegenüber der Z-Achse nur sehr klein ist. Dadurch ist die Komponente in der Z-Richtung der Aktuatorbewegung im Verhältnis zu den Komponenten in die X-Richtung und die Y-Richtung groß, also die Komponenten der Aktuatorbewegung in die X-Richtung und die Y-Richtung klein.The 4a shows the fourth embodiment of the invention, in which the optical element 2 as an example as a mirror 2 is executed. The basic structure of the actuator assembly 1 is identical to the one in 3a to 3c described embodiments of the invention. The mirror 2 is with a retaining element 8th connected via actuators 4 and leaf springs 7 on a supporting structure 6 is connected. In the in 4a described embodiment of the invention is the holding element 8th as a paragraph 8th running in the middle of the bend line of the mirror 2 is arranged, causing parasitic surface deformations due in addition to the mirror 2 introduced tensile and compressive stresses are avoided. Paragraph 8th and the mirror 2 are together as a part, so made in one piece to minimize material differences, such as thermal expansion coefficients and material inhomogeneities as possible causes of tension and to be able to produce the reference surfaces to each other by a production in a single clamping with the best possible accuracy. The actuators 4 are in this embodiment as piezo drives 4 trained and via a universal joint 22 with the attachment points to the support structure 6 and the paragraph 8th connected. The universal joint 22 is designed as a monolithic leaf spring assembly with two successively connected and rotated by 90 ° arranged leaf springs and is like the wire in the embodiments described above in the direction of the Z-axis stiff and soft in all other directions of movement and thus transmits only forces in the direction of leaf springs. The embodiment shown is for the displacement, tilting and deformation of the mirror 2 trained in the following Zernikes.

• - Translation in X - Y - and Z Direction, where the Z direction is the main direction
• - Z5 . Z6, Z10 . Z11 and Z17

The translations in X Direction and Y Direction can only be realized if the actuators 4 , as in 4a shown with an angle of attack 23 opposite the Z Axis, that is the optical axis of the mirror 2 are aligned, because only then the direction of action of the actuator 4 a component in X - and Y Direction. The actuators 4 are each tangent to their attachment points in the support structure 6 employed and two actuators each 4 are tilted to each other. The tangential tilt of the actuators 4 has the advantage that the required radial space is minimized, with any other tilt from the Z Lead out to the same result. The Z Direction is the main direction in which the in 4a illustrated optical element 2 should be moved, causing the angle of attack 23 opposite the Z -Axis is very small. This is the component in the Z Direction of the actuator movement relative to the components in the X Direction and the Y Direction big, so the components of the actuator movement in the X Direction and the Y Direction small.

The 4b shows a detailed view of the fourth embodiment of the invention, the arrangement of the leaf springs 7 shows. The leaf springs 7 are peripherally connected as in the embodiments described above at the locations where also the attachment points of the actuators 4 are arranged, but unlike the monolithic connection in the 3a - 3c , via screw connections with the supporting structure 6 and the paragraph 8th connected. This has the advantage that the leaf springs are mounted only when at a first assembly or adjustment of the mirror 2 to the support structure 6 the optical element 2 with the holding element 8th by the movement of the actuators in X Direction or Y Direction or by the rotation around the Z -Axis has been moved to an optimal position, the connection of the support structure 6 with the paragraph 8th through the leaf springs 7 the rigidity of the actuator assembly 1 in the XY Increase level.

In the 4a and 4b shown Aktuatoranbindung can by an extension with an additional actuator, which is arranged radially offset from the actuators shown, the Zernikes Z7 . Z8 . Z12 . Z13 . Z19 and Z20 adjusted, with the introduction of moments and radial ripples can be adjusted. In the 4a and 4b illustrated embodiment with the direct connection of the piezoelectric drives 4 designed actuators 4 to the support structure 6 and the paragraph 8th is suitable for active control and can be used in conjunction with a control unit, not shown, also to dampen vibrations in the eigen-modes of the mirror, which can be excited by external disturbances in the form of sound or vibration.

All embodiments shown can be with eight actuators 4 on a diameter or with eight pairs of actuators 5 be configured, wherein the actuator pairs 5 are designed so that the actuators 4 . 4 ' are arranged on two radii but in the same angular position and by the radial offset of the points of application of the actuators 4 . 4 ' a radial moment on the heel 8th and with it on the mirror 2 exercise.

In 5 is a schematic representation of an actuator assembly 1 shown, in addition to the actuator assembly 1 also a control unit 26 and a sensor unit 25 shows. The sensor unit 25 is in this embodiment of the invention on the abutment 15 attached and designed to hold data about the position and the deformation of the optical element 2 can capture. The sensor unit 25 is with the control unit 26 connected, in turn, with the actuator 4 connected is. The control unit 26 evaluates those of the sensor unit 25 recorded data of the position and the deformation of the optical element 2 off and puts on the control of the actuators 4 the desired position and the desired deformation of the optical element 2 on. The sensor unit 25 may also consist of various sensors, such as a sensor for measuring the solid state displacement of the optical element 2 and another sensor for measuring the deformation of the optical element 2 ,

In 6 is an exemplary projection exposure machine 31 represented, in which the invention can be used. The projection exposure machine 31 is used to illuminate structures on a substrate coated with photosensitive materials, which generally consists predominantly of silicon and as wafers 32 is referred to, for the production of semiconductor devices, such as computer chips.

The projection exposure machine 31 essentially comprises a lighting device 33 , a reticle stage 34 for receiving and exact positioning of a structured mask, a so-called reticle 35 through which the later structures on the wafer 32 be determined, a wafer day 36 for holding, moving and exact positioning of just this wafer 32 and an imaging device, namely a projection lens 37 , with several optical elements 38 that about versions 39 in a lens housing 40 of the projection lens 37 are held.

The basic principle of operation provides that in the reticle 35 introduced structures on the wafer 32 be imaged; the image is usually scaled down.

The lighting device 33 Represents one for the picture of the reticle 35 on the wafer 32 required projection beam 41 in the form of electromagnetic radiation ready. The source of this radiation may be a laser, a plasma source or the like. The radiation is in the lighting device 33 via optical elements shaped so that the projection beam 41 when hitting the reticle 35 has the desired properties in terms of diameter, polarization, wavefront shape and the like.

Over the projection beam 41 becomes an image of the reticle 35 generated and from the projection lens 37 correspondingly reduced to the wafer 32 transferred, as already explained above. This can be the reticle 35 and the wafer 32 be moved synchronously, so that practically continuously during a so-called scanning areas of the reticles 35 on corresponding areas of the wafer 32 be imaged. The projection lens 37 has a plurality of individual refractive, diffractive and / or reflective optical elements 38 , such as lenses, mirrors, prisms, end plates and the like, these optical elements 8th For example, can be actuated by one or more of the actuator arrangements described herein.

In 7 is one with the general reference numeral 110 provided Auflichtmikroskop for light and / or dark field microscopy for inspecting an object 112 in an object plane 114 shown. Such a reflected light microscope 110 is part of a wafer inspection system 111 , The reflected-light microscope 110 has a lens 116 and a light source 118 on, which generates light with a broadband spectrum. That from the light source 118 emitted light is in a lighting device 119 of reflected-light microscope 110 guided.

The spectrum of the light source here comprises at least one wavelength range which has the DUV wavelength range or the VUV wavelength range. That from the light source 118 emitted light is in the bright field mode of the incident light microscope 110 along a first illumination path 120 in the lens 116 guided. Inside the lens 116 is a first reflective element 122 , the present as a beam splitter 122a is formed, and a first optical assembly 124 The present invention is a catadioptric imaging lens 124a is. By the arrangement of the first reflective element 122 and the first optical assembly 124 inside the lens 116 becomes an optical axis 126 established.

In the lens 116 runs a beam path 127 moving along the optical axis 126 extends. Inside the lens 116 are between the first reflective element 122 and the first optical assembly 124 also a second 128 and third optical assembly 130 arranged. In the present case, the second optical assembly 128 and the third optical assembly 130 exclusively refractive optics. It is understood, however, that the second optical assembly 128 or the third optical assembly 130 can also have reflective optics.

The lighting device 119 also has a separate to the first illumination path 120 extending second illumination path 132 on, in the second illumination path 132 guided illumination light by means of a second reflective element 134 along the optical axis 126 between the second optical assembly 128 and the third optical assembly 130 in a pupil plane 136 arranged or can be arranged, in the beam path 127 of the lens 116 can be coupled. Through the second illumination path 132 in the present case, a dark field illumination of the object plane 114 causes, that of the light source 118 coming light for coupling into the beam path 127 of the lens 116 along a third 138 and a fourth reflective element 140 in the second illumination path 132 is guided.

The surface of the object 112 in the case of a wafer inspection system, the wafer 112 , gets through the first optical assembly 124 in the direction of the first reflective element 122 shown, in which case the object 112 backscattered or reflected light in an imaging path 142 is guided, the opposite of the first illumination path 120 runs. The picture path 142 is here by the first reflective element 122 in the direction of a detector 144 reflected and imaged on this.

The transmissivity and the reflectivity of the first reflective element 122 in the wavelength range of the light source 118 emitted light in the present case are each 50%. To image the object 112 coming light is also between the first reflective element 122 and the detector 144 another optical assembly 146 arranged. The further optical assembly 146 is shown here only schematically, which in principle may also have a plurality of refractive or reflective elements (not shown).

For coupling light into the first illumination path 120 is also the first reflective element 122 along the optical axis 126 upstream, a fifth reflective element 148 arranged, that of the light source 118 coming light in the direction of the first illumination path 120 reflected.

In brightfield mode of the reflected light microscope 110 (shown with broken lines) becomes the fourth reflective element 140 positioned so that it does not match that of the light source 18 emitted light interacts. The one from the light source 118 emitted light beam thus acts directly on the fifth reflective element 148 , The fifth reflective element 148 directs that from the light source 118 coming light in the direction of the first illumination path 120 around, creating a desired area of the object 112 in the object plane 114 illuminated in bright field mode.

In the darkfield mode of the reflected-light microscope 110 is the fourth reflective element 140 so in front of the light source 118 positioned that the light at least partially in the direction of the second illumination path 132 is reflected. Following is the light, through the third reflective element 138 in the direction of the second reflective element 134 deflected the light into the beam path 127 of the lens 116 couples, creating a desired area of the object 112 in the object plane 114 illuminated in dark field mode.

LIST OF REFERENCE NUMBERS

1

actuator

2

optical element

3

depository

4,4 '

actuator

5

of actuators

6

supporting structure

7

Connecting element, leaf spring

8th

retaining element

9

decoupling element

10

Power transmission element, wire

11

lever

12

joint

13.13 '

Spring, compression spring

14.14 '

Rifle

15

Counter bearing, ring

16

fluid

17

cavity

18

chamber

19

membrane

20

connecting channel

21

cover

22

universal joint

23

Angle of attack actuator

24

elastic line

25

sensor unit

26

control unit

31

Projection exposure system

32

wafer

33

lighting device

34

Reticle Stage

35

reticle

36

wafer stage

37

projection lens

38

Optical element

39

version

40

lens housing

41

projection beam

110

reflected light microscope

111

Wafer inspection system

112

Object, wafer

114

object level

116

lens

118

light source

119

lighting device

120

First lighting path

122, 122a

first reflective element

124, 124a

first optical assembly

126

optical axis

127

beam path

128

second optical assembly

130

third optical assembly

132

second illumination path

134

second reflective element

136

pupil plane

138

third reflective element

140

fourth reflective element

142

picture path

144

detector

146

additional optical module

148

Fifth reflective element

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19327603 A1 [0003]

Claims (24)

Actuator assembly (1) comprising - an optical element (2) held by a holding element (8), - a support structure (6), - actuators (4) adapted to force and / or force the holding element (8), or exert moments, characterized in that the holding element (8) is arranged such that the forces exerted by the actuators (4) and / or moments cause deformation of the holding element (8) and thus deformations of the optical element (2). Actuator assembly (1) according to Claim 1 , characterized in that at least 8 actuators (4) engage the retaining element (8). Actuator assembly (1) according to Claim 2 , characterized in that the actuators (8) are arranged so that in the optical element (2) tangential Einwelligkeiten, two ripples, three ripples, four ripples and a radial ripple can be impressed. Actuator assembly (1) according to one of the preceding claims, characterized in that at least one actuator (4) in the middle of the bending line (24) of the optical element (2) on the holding element (8) engages. Actuator assembly (1) according to one of the preceding claims, characterized in that an individual force is adjustable on each actuator (4). Actuator assembly (1) according to one of the preceding claims, characterized in that a control unit is present, which comprises a measuring system for measuring the deformation of the optical element (2) and a controller for calculating the Aktuator force and / or the Aktuatorverfahrweges and which at least one Actuator (4) is connected. Actuator assembly (1) according to Claim 6 , characterized in that at least one actuator (4) can be controlled by the control unit (26) in a semi-active operating mode. Actuator assembly (1) according to Claim 6 , characterized in that at least one actuator (4) can be controlled by the control unit (26) in an active operating mode. Actuator assembly (1) according to Claim 8 , characterized in that the control unit (26) is arranged so that eigenmodes of the holding element (8) and the optical element (2) are attenuated by driving the actuators (4). Actuator assembly (1) according to one of the preceding claims, characterized in that at least one connecting element (7) between the holding element (8) and the support structure (6) is arranged. Actuator assembly (1) according to Claim 10 , characterized in that at least one connecting element (7) between the holding element (8) and the support structure (6) is designed as a leaf spring (7). Actuator assembly (1) according to Claim 10 or 11 , characterized in that the connecting elements (7) and the actuators (4) are arranged in pairs circumferentially at the same points of attack of the holding element (8) and the support structure (6). Actuator assembly (1) according to Claim 10 or 11 , characterized in that the connecting elements (7) are arranged circumferentially between the points of engagement of the actuators (4) on the holding element (8) and the support structure (6). Actuator assembly (1) according to one of the preceding claims, characterized in that the effective directions of the actuators (4) are aligned parallel to the optical axis. Actuator assembly (1) according to Claim 1 to 13 , characterized in that the directions of action of the actuators (4) are not aligned parallel to the optical axis. Actuator assembly (1) according to Claim 15 , characterized in that the effective directions of the actuators (4) relative to the support structure (6) are tilted in the tangential direction. Actuator assembly (1) according to one of Claims 15 or 16 , characterized in that the effective directions of each two adjacent actuators (4) are tilted to each other. Actuator assembly (1) according to one of the preceding claims, characterized in that the forces and / or moments of the actuator (4) via a lever (11) are transmitted to the holding element (8). Actuator arrangement according to Claim 18 , characterized in that the lever (11) and the holding element (8) via a wire (10) are interconnected. Actuator assembly (1) according to Claim 18 or 19 , characterized in that between the actuator (4) and lever (11), a first spring (13) is arranged, wherein the bias of the spring (13) is adjustable. Actuator assembly (1) according to Claim 18 , 19 or 20, characterized in that between the holding element (8) and the support structure (6), a second spring (13 ') is arranged, wherein the bias of the second spring (13') is adjustable. Actuator assembly (1) according to Claim 18 . 19 or 20 characterized in that in the support structure (6) there is a fluid filled cavity (17) with chambers (18) closed with a membrane (19) and the chambers (18) are located at the points where Lever (11) on the holding element (8) engages and the membranes (19) contact the holding element (8) on the point of application of the lever (11) opposite side. A projection exposure apparatus for semiconductor lithography with an actuator arrangement according to one of the preceding claims. Wafer inspection system for semiconductor lithography with an actuator arrangement according to one of the preceding Claims 1 - 22 ,

Images