WO2022148698A1

WO2022148698A1 - Optical device and method for controlling an optical device

Info

Publication number: WO2022148698A1
Application number: PCT/EP2021/087781
Authority: WO
Inventors: Ralf AMELING
Original assignee: Carl Zeiss Smt Gmbh
Priority date: 2021-01-08
Filing date: 2021-12-29
Publication date: 2022-07-14
Also published as: EP4275095A1; JP2024502844A; DE102021200113A1

Abstract

The invention relates to an optical device (1) having a plurality of optically active surfaces (2), wherein each of the surfaces (2) can be tilted by means of its own, autonomously controlled manipulation device (3) associated with the surface (2). According to the invention, the manipulation device (3) is designed to position and/or bend the surface (2), and a total controller (4) is provided which controls the manipulation devices (3) such that at least two of the surfaces (2) produce a total surface (5) in a planned and coordinated interaction.

Description

Optical device and method for controlling an optical device

The present application claims the priority of German Patent Application No. 10 2021 200 113.0, the content of which is incorporated herein by reference in its entirety.

The invention relates to an optical device having a plurality of optically active surfaces, wherein the surfaces can each be tilted by means of a separate, autonomously controllable manipulation device assigned to the surface.

The invention also relates to a method for controlling an optical device which has a plurality of optically active surfaces, each surface being able to be controlled autonomously in order to tilt the surface.

In a known manner, optical elements influence the properties of light waves interacting with them. In particular, surfaces of optical elements make a significant contribution to this influence, since reflection and/or refraction can take place on the surfaces, for example. Examples of optical elements that can be mentioned are planar mirrors, concave mirrors, convex mirrors, facet mirrors, convex lenses, concave lenses, convex-concave lenses, plano-convex lenses and plano-concave lenses. In this case, surfaces of concave mirrors and convex mirrors have radii of curvature, as a result of which a focal point or focus can be formed, for example.

A multiplicity of segment-like, planar and/or curved individual mirrors are combined in a facet mirror. In this case, the segment-like individual mirrors can be tilted, so that each segment-like individual mirror can reflect light incident on the facet mirror in a different direction.

Projection exposure systems have a large number of optical elements. In particular when using the optical elements in a microlithographic DUV (Deep Ultra Violetj projection exposure system and very particularly when using them in a microlithographic EUV (Extreme Ultra Violetj) projection exposure system, dynamic adaptability of the optical elements, for example to implement different lighting modes, is special meaning.

In the illumination system of EUV lithography systems, field facets of a field facet mirror are assigned to differently positioned pupil facets. Due to the different angles and the different distances, no optimal spot size can be set. The known technical solutions all deviate more or less from an ideal picture, with external interference, such as thermal effects, also limiting the adjustability. This leads to losses in transmission and poorer imaging properties of the known systems. DE 10 2015 204 874 A1 discloses a displacement device for pivoting a mirror element with two pivoting degrees of freedom, which comprises an electrode structure with actuator electrodes, the actuator electrodes being designed as comb electrodes. In this case, all the actuator electrodes are arranged in a single plane and the actuator electrodes form a direct drive for pivoting the mirror element.

An optical element with an imaging error and position correction device is known from GB 2468557 A.

The disadvantage of macroscopic facet mirrors known from the prior art, in particular field facet mirrors, with fixed radii of curvature of the facets is the fact that when the segment-like individual mirrors are dynamically tilted, a position of a focus does not coincide with a new target segment, since a curvature of the individual mirror another target segment is optimized.

Furthermore, by tilting the individual mirrors, it is not possible to form a focal point, which is formed by the interaction of a number of individual mirrors.

The disadvantage of optical elements known from the prior art for projection exposure systems is that their focal point properties cannot be dynamically adjusted during operation of the projection exposure system.

A displacement device for pivoting a mirror element is known from the aforementioned DE 102015204874 A1, which is at least partially formed using so-called MEMS technology (microelectromechanical system technology).

Another disadvantage of optical elements known from the prior art is that they are constructed from a plurality of components, which can lead to an increased risk of malfunction and/or failure.

The present invention is based on the object of creating an optical device which avoids the disadvantages of the prior art, and in particular enables improved adjustability.

According to the invention, this object is achieved by a device having the features specified in claim 1.

According to the invention, this object is also achieved by a device having the features specified in claim 2 . The present invention is also based on the object of creating a method for controlling an optical device which avoids the disadvantages of the prior art and in particular enables improved adjustment.

According to the invention, this object is achieved by a method having the features specified in claim 13 .

The present invention is based on the object of creating a computer program product which avoids the disadvantages of the prior art and in particular enables improved adjustment.

The present invention is based on the object of creating a lithography system which avoids the disadvantages of the prior art, in particular having optical elements, in particular at least one field facet mirror, which enables improved imaging.

The optical device according to the invention according to claim 1 has a plurality of optically active surfaces, wherein the surfaces can each be tilted by means of a separate, autonomously controllable manipulation device assigned to the surface. According to the invention, the manipulation device is set up to position and warp the surface, with an overall control device being provided which controls the manipulation devices in such a way that at least two of the surfaces result in a total surface in a planned and coordinated interaction.

The optical device according to the invention according to claim 2 has a plurality of optically active surfaces, wherein the surfaces can each be tilted by means of a separate, autonomously controllable manipulation device assigned to the surface. According to the invention, it is provided that the manipulation device is set up to position and/or warp the surface, with an overall control device being provided which controls the manipulation devices in such a way that at least two of the surfaces result in a total surface in a planned and coordinated interaction, with each surface has its own control device, which is set up to control the tilting and the curvature and/or the positioning of the respective surface, and the overall control device controls all surfaces in such a way that, while maintaining a defined tilting of the individual surfaces, the surfaces are positioned overall in such a way and /or are warped, that gaps between adjacent, mutually tilted surfaces of the overall surface are reduced, preferably minimized.

Advantageous features and configurations of the two devices according to the invention are described below.

By combining the degree of freedom of tilting with at least one of the two degrees of freedom of curvature and/or positioning, the Total surface can be shaped almost freely. This has the advantage that a large number of different shaping and guiding effects can be exerted on a wave front incident on the optical device by means of a single optical device.

A well-planned and coordinated interaction can be understood in particular as an interaction of the surfaces that is coordinated with one another.

Furthermore, it can be provided that the total surface is formed by at least one group, preferably a majority, in particular over 90 percent of the surfaces.

The adjustability of the optical element is significantly improved by the additional degrees of freedom, such as the movement of the surface in a direction orthogonal to the surface and/or the change in the radius of curvature of the surface.

This also makes it possible to compensate for disruptive effects, such as the curvature of the surface due to thermal effects. Although the optical devices known from the prior art are suitable for tilting the surfaces in a desired manner, a height adjustment, i. H. an adjustment orthogonal to the surface of the mirrors, is possible or deformations of the surface can be compensated for, however, the known optical devices do not disclose a planned and coordinated control of the surfaces in such a way that an overall surface, i. H. an overall surface of any shape within the system limits, can be set.

It is of particular advantage if the individual surfaces can be controlled in such a way that, preferably simultaneously, a tilting of the respective surface, a height adjustment of the surface and a curvature or a deformation of the surface can be carried out or set.

Within the scope of the invention, the surfaces can in particular be surface segments.

The device according to the invention therefore makes it possible to simulate any optical surface even more precisely than in the prior art.

In an advantageous development of the optical device according to the invention, it can be provided that the overall control device is set up to control the manipulation devices in such a way that gaps between adjacent, mutually tilted surfaces are reduced by positioning and/or bending the surfaces.

The device according to the invention therefore enables a configuration through a tilting of individual surfaces in combination with their translational positioning and/or their curvature an area formed by the surfaces which has a reduced occurrence of gaps between the individual surfaces.

Within the scope of the invention, offsets between the individual surfaces can also be understood as gaps which are formed in the direction of the surface normal and not in the plane of the surfaces.

A surface designed in this way offers the advantage that interference with the radiation-shaping function of the surface due to gaps between surfaces is reduced.

Within the scope of the invention, it has been found that a combination of a tilting of the surfaces with their positioning and/or their curvature enables sufficiently good avoidance of gaps.

Adjacent surfaces can be understood to be tilted relative to one another if at least one of the surfaces is tilted from its initial orientation.

In an advantageous development of the optical device according to the invention, it can be provided that the overall control device controls the manipulation devices in such a way that gaps between adjacent surfaces that are tilted relative to one another are minimized by positioning and/or warping the surfaces.

A minimization of the latter, going beyond a mere reduction of the gaps, consequently makes it possible to minimize the disturbances in the radiation shaping function of the surface.

In an advantageous development of the optical device according to the invention, it can be provided that the manipulation device has a tilting device in order to tilt the surface relative to an initial alignment of a mean surface normal of the surface, and the manipulation device has a curvature device in order to curve the surface and/or a Positioning device has to raise or lower the surface plane-parallel to a starting position

A further development can also be advantageous in which it is provided that the tilting device and the bending device and/or the positioning device are designed as independent devices.

A combination of the two aforementioned developments can be particularly advantageous, it being possible for the manipulation device to have a tilting device in order to tilt the surface in relation to an initial alignment of a mean surface normal of the surface, and the manipulation device to have a curvature device in order to curve the surface. and/or has a positioning device in order to raise or lower the surface in a plane-parallel manner in relation to an initial position, the tilting device and the curving device and/or the positioning device being designed as independent devices.

If the manipulation device has a tilting device as well as a bending device and/or a positioning device in an at least two-part design, there is the advantage of a clear separation of the functional elements, which leads, for example, to a reduced susceptibility to errors in the manipulation device, since a failure of a single functional element, for example the tilting device , does not lead to a failure of the remaining functional element(s).

It is particularly advantageous if the manipulation device has a tilting device, a bending device and a positioning device, each of which is designed as an independent device.

In this case, the surface is tilted individually by the tilting device, preferably about two axes in each case, resulting in two degrees of freedom f _c and f _n .

Furthermore, the effect of the positioning device, which raises or lowers the surface in a plane-parallel manner in relation to an initial position, results in a further degree of freedom in the z-direction.

The curvature device provides a further degree of freedom for the shaping of the surface, preferably by forming at least two radii of curvature R _x and R _y .

The aforementioned degrees of freedom f _c and f _n , z, R _x , R _y are available for shaping each surface and allow a particularly efficient shaping of an overall surface composed of the surfaces, which has a particularly efficiently minimized formation of gaps.

It is advantageous if the manipulation device has a tilt control device for controlling the tilting device and a positioning control device for controlling the positioning device and/or a curvature control device for controlling the curvature device.

Insofar as the tilting device, the positioning device and the curvature device can be controlled by respective suitable control devices, each of the aforementioned degrees of freedom for shaping the surface can preferably be set, controlled and in particular regulated.

In particular, to enable regulation, it can be provided that the tilt control device and/or positioning control device and/or the curvature control device have sensors, which are set up to determine the tilting and/or the curvature and/or the positioning.

In particular, it can be provided that the curvature control device and/or the overall control device has piezoresistive sensors in order to measure a current mirror curvature and thus form a regulated system.

This can, for example, make it possible to compensate for thermal effects.

It is advantageous if the tilt control devices and the positioning control devices and the curvature control devices are designed independently and/or as part of the overall control device.

Furthermore, it can be provided, for example, that only some of the surfaces can be controlled individually, while the respective remainder can be controlled in that the relevant tilt control devices and positioning control devices and curvature control devices are part of the overall control device.

It is also of particular advantage if the overall control device and/or the respective tilt control devices and positioning control devices and curvature control devices each have at least one control device which regulates the expression of the aforementioned degrees of freedom f _c , f _n , z, R _x and R _y .

It is advantageous if the overall control device is set up to approximate a desired shape of the overall surface by means of the surfaces by controlling the tilting devices and/or the bending devices and/or the positioning devices.

It is particularly advantageous if the overall control device controls the tilting device and/or the bending devices and/or the positioning devices in such a way that the overall surface made up of the individual surfaces corresponds at least approximately to a desired overall shape.

To this end, it is particularly advantageous if the overall control device is set up to execute a computer program product that simulates such an approximation and/or implements it through mathematical modelling.

Furthermore, it can be advantageous if a sensor device is provided in order to measure a wavefront emanating from the overall surface and thus to check and evaluate the interaction of the surfaces and, if necessary, to regulate or adjust the alignment of the surfaces, preferably iteratively, using the overall control device. to readjust. It is advantageous if a feedback device is provided, for example as part of the overall control device, which approximates an actual state, determined by the sensor device, of the wavefronts emanating from the entire surface to a target state in that the overall control device causes or regulates that the surfaces tilted and/or positioned and/or curved.

It is advantageous if the surfaces adjoin one another at least approximately seamlessly.

If the surfaces join together at least approximately seamlessly, the occurrence of gaps is at least approximately completely eliminated.

As a result, the entire surface can fulfill the desired beam shaping function at least approximately without restrictions.

It is also advantageous if the overall surface is designed in such a way that the overall surface has a single focus point or a multiplicity of discrete focus points.

In an advantageous interaction, the individual surfaces can form a concave mirror, for example, which has a single focal point.

It can be of particular advantage if the overall surface has a large number of discrete focus points, for example in order to illuminate different and spatially separated target structures.

Such a desired shape of the overall surface can be advantageously, precisely and reliably approximated with the optical device according to the invention.

It is advantageous if the surfaces are designed to reflect light, in particular EUV light.

If the surfaces are designed to be light-reflecting and, in particular, EUV light-reflecting, the optical device can be used, for example, as a formable mirror and in particular, for example, as a field facet mirror of an EUV projection exposure system.

It is advantageous if at least some of the surfaces have a reflective layer system formed at least on part of the respective surface.

To increase the reflectivity of the respective surface, particularly in the wavelength range of an EUV light, a reflective layer system can be advantageous which is at least partially formed on the surface, since reflective layer systems reliably have high degrees of reflectivity in an EUV wavelength range. It is advantageous if the curvature device is set up so that the surface has a curvature of less than 20 1/m, preferably between 0.2 1/m and 20 1/m, preferably between 0.5 1/m and 4 1/m. m, in particular between 1 1/m and 2 1/m.

Limiting the degrees of freedom of the radii of curvature R _x and R _y has the advantage that mechanical stress on the surface, in particular on a reflection layer system that may be formed on the surface, is limited, which means that damage to the reflection layer system can be avoided.

As a result, advantageously long service lives of the respective surfaces and thus of the entire optical device can be achieved.

Limiting the curvature to less than 20 l/m, preferably less than 10 l/m, in particular to less than 2 l/m, has proven to be advantageous within the scope of the invention.

Furthermore, it has proven to be advantageous if the curvature device is set up to form a curvature of at least 0.2 1/m on the surface. The curving means should advantageously be set up to be able to achieve such a degree of curving of the surface as to bring about an advantageous reduction in the gaps between the individual surfaces.

It is advantageous if the curvature device is set up to form at least two curvatures on the surface.

The formation of two curves, in particular two curves whose curves of curvature run at right angles to one another, is of particular advantage, since two main curves are in principle sufficient to achieve any desired curved shape of a surface.

However, it can be advantageous if the curvature device is set up to form more than two curvatures on the surface, since this allows a desired curvature or shape of the surface to be set even more accurately and precisely, for example.

A development of the invention can consist in at least one stiffening element being arranged on the surface, which preferably improves a curvature of the surface in that certain areas of the surface are stiffened and thus act, for example, as a fixed point of a curved surface.

Furthermore, it can be provided that the manipulation device has several, preferably independent, bending devices and/or tilting devices and/or positioning devices. Provision can be made, for example, for two curving devices to be arranged one above the other in order to curve the surface in different directions.

It is advantageous if the surfaces and/or the manipulation devices are arranged on a common base body.

If the surfaces are arranged on a common base body, this results in a stable common basis for the respective surfaces and the associated manipulation devices. A common base body can therefore advantageously minimize a thermally and/or mechanically induced drift of the individual surfaces and of the manipulation devices associated with the surfaces relative to one another.

Furthermore, it is advantageous if the tilting device and/or the curvature device and/or the positioning device are arranged between the base body and the respective surface.

If the elements of the manipulation device, namely the tilting device and/or the bending device and/or the positioning device, are arranged between the base body and the respective surface, this results in the advantage that the mechanical effects of the respective devices use the respective base body as an abutment and stable base and in particular that the optical properties of the surface are not impaired or impaired by devices arranged next to or on the surface.

It is advantageous if the tilting device and/or the curvature device and/or the positioning device assigned to one of the surfaces are functionally and/or physically connected to the base body and the respective surface, and preferably to one another.

If the individual devices of the manipulation device, namely the tilting device, the bending device and the positioning device, are functionally and/or spatially connected to the base body and the respective surface, this results in the advantage of a reliable transmission of force, which is necessary for the deformation of the surface by the individual devices can.

Provision can be made for one of the devices to act on the respective others in order to tilt and/or deform and/or position the surface. For example, it can be provided that the positioning device moves both the tilting device and the curvature device and also the surface. To this end, it is of particular advantage if the individual devices are physically connected to one another in such a way that such positioning can take place reliably. Furthermore, if the devices are functionally and/or physically connected to one another, such an effect of the devices on one another can also take place reliably.

Of particular advantage is a monolithic construction of the manipulation device such that the tilting device and/or the bending device and/or the positioning device are monolithically connected to one another and to the base body and the respective surface.

A desired functional and/or physical connection can be achieved particularly reliably and in particular also in miniature form by means of a monolithic construction.

It is advantageous if the tilting device and/or the bending device and/or the positioning device are designed using MEMS technology (microelectromechanical system technology).

Designing the tilting device and/or the curving device and/or the positioning device using microelectromechanical system technology or MEMS technology offers the advantage of designing the aforementioned devices on very small scale ranges, with the devices being able to be controlled by means of electrical signals and with the Signals mechanical changes in the facilities, especially mechanical effects, can be triggered or achieved.

By using electrical signals, control can be carried out advantageously, efficiently and, in particular, in a miniaturized manner.

Forming the tilting device and/or the bending device and/or the positioning device using coating methods is of particular advantage here.

It can be advantageous if the positioning device is formed by a deflectable, preferably electrostatically actuable, membrane over a cavity.

Because the positioning device is formed by a deflectable membrane over a cavity, which can preferably be actuated electrostatically, devices arranged on the membrane can advantageously be easily displaced along the surface normal of the membrane to be deflected. It is particularly advantageous that such a positioning device has a certain technical similarity to so-called MEMS microphones, as a result of which such a conversion can be carried out particularly advantageously in a simple and reliable manner.

It can be advantageous here if the membrane is monolithically connected to elements of the positioning device that hold the membrane and/or are connected to the membrane. Furthermore, it can be advantageous if the curvature device is formed by at least one stretchable and/or contractible actuator element, preferably a piezoelectric element.

A realization of the curvature device in that at least one stretchable and/or contractible actuator element, preferably a piezoelectric element, is arranged in an operative connection with the surface has the advantage that a curvature of the surface is induced by a stretching and/or contraction of the at least one actuator element can be.

The use of piezoelectric elements as actuator elements has the advantage that they can be designed in a miniaturized form and, in particular, can be controlled by electrical signals.

The advantages of electrically controlling the curvature device have already been explained in connection with MEMS technology.

It is advantageous if the curvature device is formed by at least two, preferably at least four, actuator elements arranged along at least two axes.

At least two main curvatures can be induced on the surface by at least two, preferably at least four, actuator elements. In this way, at least approximately any curvature of the surface can be realized since, according to Euler's theorem, any curvature is formed as a linear combination of the respective main curvatures, which are induced by the actuator elements arranged along at least two axes.

It can be advantageous if the curvature device is arranged between the surface and the tilting device.

An arrangement of the curvature device between the surface and the tilting device has the advantage that the surface can be curved or influenced by the curvature device without the curvature device

Tilting device also has to bend.

As a result, the curvature device can advantageously be of simple design and, in particular, can be designed for a lower potential occurrence of force.

It is advantageous if the positioning device is arranged between the tilting device and the base body.

If the positioning device is arranged below the tilting device, starting from the surface, then the tilting device does not have to tilt the positioning device in addition to the bending device that may be arranged below the surface. Since the positioning device only serving one degree of freedom, it can be the least complex and therefore designed for a greater potential output of force.

It is therefore particularly advantageous if the positioning device and on this the tilting device and on this the curvature device and on this the surface are arranged on a base body, preferably the common base body of the surface.

In an advantageous development of the device according to the invention, it can be provided that the curvature device is set up to correct any undesired deformations of the surface assigned to it.

Such a correction can be of particular advantage when, in order to use the surface, only a small part of the surface has to be curved in order to correct the undesired deformation. In this case, it can be provided that only part of the bending device is put into an operating state.

This has the advantage, for example, that less heat is introduced into the optical device for this purpose, since only part of the curvature device is operated.

To this end, it can be advantageous if a plurality, preferably more than 10, of actuator elements are arranged on the surface base body.

In this way, even small-scale unwanted deformations of the surface can be corrected.

It is advantageous if the surface is formed on a surface base body, the surface base body having a thickness of 1 to 500 μm.

The surface as a potentially very thin area arranged on the mathematical and thus abstract surface can advantageously be arranged on a surface base body that imparts stability to the surface. For this purpose, the surface base body can advantageously have a thickness of 1 to 500 μm, which within the scope of the invention has turned out to be a suitable compromise between mechanical stability and, for example, low weight of the surface base body.

It is advantageous if the actuator elements are arranged in direct contact on the surface base body.

If the actuator elements are in direct contact with the surface base body, they can shape the surface base body and with it the surface arranged on the surface base body in a particularly simple manner. For example, by contracting two along one axis arranged actuator elements, which are spaced apart, in each case a region of the surface base body are contracted, causing it to deform, which leads to a curvature of the surface base body along the axis on which the actuator elements are arranged.

It is advantageous if the actuator elements are each arranged at a distance from the surface base body on the side of the surface base body facing away from the surface.

If the actuator elements are arranged in such a way that they are spaced apart from the surface base body, this can make it easier to warp the surface, for example, since the surface base body has the option of reaching into a cavity arranged between the actuator elements and the surface base body when it bends.

In particular, such an embodiment strengthens a possible lifting effect of the actuator elements in their effect on the surface base body and thus the surface.

At least one attachment element is preferably provided, which is preferably arranged on the outer edge of the surface base body and which is set up to transmit a force applied by the actuator element or actuator elements to the surface base body.

If the curvature device is implemented by forming layers, it can be advantageous if the actuator elements are arranged and/or formed in a layer which is spaced apart from the surface base body.

It is advantageous if the surface has a hexagonal or triangular or rectangular, preferably square, shape.

In order to achieve an overall surface with as few gaps as possible, it has turned out to be advantageous if the surface is hexagonal or triangular or rectangular, but preferably square.

With a hexagonal surface, it can be advantageous if, for example, six actuator elements are arranged symmetrically under the surface.

Geometric shapes of this type enable the entire surface to be formed or tessellated to cover the entire surface without the occurrence of defects. Defects would occur, for example, on round surfaces that cannot be joined together at least approximately seamlessly to form an overall surface.

It is advantageous if the surface has a surface area of between 0.5 mm ² and 10 mm ² , preferably between 0.9 mm ² and 2 mm ² , particularly preferably 1 mm ² . The aforementioned surface areas have proven to be particularly suitable for forming a typical overall surface, for example a facet mirror in an EUV projection exposure system.

In an advantageous development of the device according to the invention, it can be provided that each surface has its own control device, which is set up to control the tilting and the curvature and/or the positioning of the respective surface, and an overall control device is provided which controls all surfaces controlled in such a way that, while maintaining a defined tilting of the individual surfaces, the surfaces are positioned and/or curved overall in such a way that gaps between adjacent surfaces of the overall surface that are tilted relative to one another are reduced, preferably minimized.

In particular, provision can be made for the tilting and/or curvature and/or positioning to be carried out iteratively one after the other and optionally multiple times controlled by the overall control device such that the overall surface gradually assumes a shape desired by the overall control device.

The invention also relates to a method for controlling an optical device which has a plurality of optically active surfaces.

In the method according to the invention for controlling an optical device, which has a plurality of optically active surfaces, each surface being able to be controlled autonomously in order to tilt the surface, it is provided that the surfaces are tilted and/or positioned and/or curved in such a way that at least two of the surfaces result in a total surface in a planned and coordinated interaction.

With an overall surface achieved in this way, an incident wave front can be influenced over a large area, in a planned and coordinated manner.

In the method according to the invention, it is provided that the degree of freedom of the tilting of the surface can be used to form the overall surface. In addition to the degree of freedom of tilting, the degree of freedom of curvature of the surface and/or the degree of freedom of positioning the surface can also be used.

It should be noted here that the respective degrees of freedom do not have to be used. For the method according to the invention, however, they must be potentially usable in at least one of the three combinations of tilting plus bending and/or tilting plus positioning and/or tilting plus bending plus positioning. In particular, in the method according to the invention, one or more or even all of the usable degrees of freedom cannot be used for individual surfaces which are used to form the overall surface. In the method according to the invention, however, the unused degrees of freedom are potentially available.

In an advantageous development of the method according to the invention, it can be provided that the mutually tilted surfaces are positioned and/or curved relative to one another in such a way that gaps between adjacent surfaces tilted relative to one another are reduced, preferably minimized.

As a result, on an overall surface of the optical device, the reduction in the gaps results in areas at which incident light is only slightly disturbed by gaps. These areas can be formed by individual, a multiplicity or all of the plurality of optically active surfaces.

The reduction of gaps increases the optical performance of the overall surface formed as a result in a cumulative and orchestrated manner.

It is advantageous if the mutually tilted surfaces are positioned and/or curved relative to one another in such a way that gaps between adjacent mutually tilted surfaces are minimized.

If the gaps between adjacent surfaces that are tilted relative to one another are minimized by the method, this leads to further improved optical properties of the respective cumulative total surface.

Furthermore, it can be provided that at least some of the surfaces that form the overall surface are not tilted.

It is advantageous if the surfaces are tilted in such a way that the respective surface is tilted relative to an initial alignment of a mean surface normal of the surface, and the surfaces are curved in such a way that the respective surface is curved, and/or the surfaces are positioned takes place in such a way that the respective surface is raised or lowered plane-parallel with respect to an initial position.

A plane-parallel lowering or raising of the respective surface is understood to mean any translational movement of the surface that occurs along the initial alignment. It is advantageous if the tilting and/or the curvature and/or the positioning of a surface is carried out by independent devices that can be controlled independently of one another.

The resulting degrees of freedom can be set independently of one another by independently controlling the tilting, the bending and the positioning. In particular, in such an embodiment, the method can independently access the degrees of freedom opened up by the tilting and/or bending and/or positioning.

It can be advantageous if, while maintaining a defined tilting of the individual surfaces, the surfaces as a whole are positioned and/or curved in such a way that gaps between adjacent, mutually tilted surfaces of the overall surface are reduced, preferably minimized.

In this way, for example, a position of a focal point in space can be realized without changing a tilting of the controlled ensemble of surfaces.

In particular, provision can be made for the method steps of tilting and/or curvature and/or positioning to be carried out iteratively one after the other and, if necessary, multiple times in such a way that the overall surface gradually assumes a shape desired by the overall control device.

It is advantageous if the surfaces are each curved along at least two axes in such a way that at least two radii of curvature result for the respective surface.

A curvature of the surface along at least two axes such that there are at least two degrees of curvature on the surface has the advantage that any curvature on the surface can be represented at least approximately as a linear combination of the main curvatures by two main curvatures.

It is particularly advantageous here if the at least two axes do not coincide. Preferably, the two axes are perpendicular to each other.

If more than two axes are provided, it is advantageous if these are arranged symmetrically and preferably all run through the surface normal, which breaks through the surface at a centroid.

Furthermore, it can be advantageous if the surfaces are curved in that at least one actuator element arranged below the surface is stretched and/or contracted. A curvature caused by an actuator element has the advantage that the actuator element can be implemented in a space-saving, easily controllable manner and, in particular, by a piezoelectric element, for example.

MEMS technology as a sub-area of microsystems technology offers the possibility of realizing electrically controlled mechanical systems on very small scales, at the lower limit of the size scale down to a size of 1 pm. Such small structures can be realized, for example, by means of coating technology. For this purpose, the small-scale structures are applied to one another as layers and/or etched away.

It is therefore advantageous in the method according to the invention that the overall surface is formed from a plurality of surfaces which are tilted and/or curved and/or shifted in a coordinated manner.

By a coordinated and / or orchestrated combination of individual surfaces in such a way that they form the overall surface, and the surfaces are positioned in particular to each other, being tilted and / or bent and / or shifted in a coordinated manner, it can be achieved that the overall surface looks like one only optically active surface acts. As a result, the overall surface, which acts like a single optical element, can be formed by a large number of individual surfaces, which can be assigned to individual optical elements, for example, by forming a common surface of these individual surfaces.

For example, the surfaces may interact such that the overall surface acts like a parabolic mirror with a single focus. Such an effect of the entire surface of a facet mirror according to the prior art is not possible by simply tilting the surfaces, even if it is coordinated.

It is advantageous if the surfaces are tilted and/or curved and/or shifted in a coordinated manner in such a way that an at least approximately smooth overall surface is formed.

If an at least approximately smooth overall surface is formed, then aberrations which occur at sharp gaps and/or edges and/or offsets can be reduced.

It is also advantageous if the overall surface is shaped in such a way that one or more focal points are formed.

If the overall surface is shaped in such a way that one or more focal points are formed, then, for example, a large number of points on a pupil facet mirror can be irradiated with a particularly high, since focused, intensity. It is advantageous if the overall surface is shaped in such a way that the position and/or the number of the one or more focal points is changed during use of the device.

The change can preferably take place continuously and/or discontinuously.

A dynamic change in the overall surface has the advantage that it is possible to react to changing demands on the illuminance in different areas of a downstream optic. In particular, it is also advantageous if a dynamic reshaping of the overall surface can be used to react to possible fluctuations in the light radiating onto the overall surface and its intensity distribution.

Furthermore, a mixing of the light between the field facet mirror and the pupil facet mirror can also be changed during use by dynamically changing the overall surface.

An advantageous further development of the method according to the invention can consist in changing the shape of the overall surface while it is being used to form wave fronts.

In particular, it can be provided, for example, that more than 100 surfaces, preferably more than 1000 surfaces, which form a total surface, are all tilted and/or curved and/or positioned in less than 5 seconds, preferably in less than 2 seconds. In this case, other surfaces can also contribute to the formation of the overall surface, which are neither tilted nor bent nor positioned.

The invention also relates to a computer program product with program code means to carry out a method according to the invention according to the above and following explanations when the program is executed on a device, in particular an overall control unit of an optical device according to the invention according to the above and following explanations.

The device can be designed as a microprocessor. Instead of a microprocessor, any other device can also be provided for implementing the device, for example one or more arrangements of discrete electrical components on a printed circuit board, a programmable logic controller (PLC), an application-specific integrated circuit (ASIC) or another programmable circuit, for example also a field programmable gate array (FPGA), a programmable logic array (PLA), and/or a commercial computer.

Execution of the computer program product on a device which is provided for operation and for checking the functionality in a lithography system, in particular a projection exposure system, and is already implemented in this according to the prior art is particularly advantageous. The invention also relates to a lithography system, in particular a projection exposure system.

The lithography system according to the invention, in particular a projection exposure system for microlithography, has at least one optical element. According to the invention, it is provided that at least one of the optical elements, in particular a field facet mirror and/or a pupil facet mirror, is formed by an optical device according to the invention and/or is controlled by a method according to the invention and/or a computer program product with program code means is provided according to the invention for a method according to the invention to be carried out when the program is executed on a device, in particular an overall control device of an optical device according to the invention.

Features that have been described in connection with one of the objects of the invention, specifically given by the optical device according to the invention, the method according to the invention, the computer program product and the lithography system, can also be advantageously implemented for the other objects of the invention. Likewise, advantages that were mentioned in connection with one of the objects of the invention can also be understood in relation to the other objects of the invention.

In addition, it should be pointed out that terms such as "comprising", "having" or "with" do not exclude any other features or steps. Furthermore, terms such as "a" or "that" which indicate a singular number of steps or features do not exclude a plurality of features or steps - and vice versa.

In a puristic embodiment of the invention, however, it can also be provided that the features introduced in the invention with the terms “comprising”, “having” or “with” are listed exhaustively. Accordingly, one or more listings of features may be considered complete within the scope of the invention, e.g. considered for each claim. The invention can consist exclusively of the features mentioned in claim 1, for example.

It should be mentioned that designations such as "first" or "second" etc. are primarily used for reasons of distinguishing between respective device or method features and are not necessarily intended to indicate that features are mutually dependent or related to one another.

Exemplary embodiments of the invention are described in more detail below with reference to the drawing.

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

Elements with the same function are provided with the same reference symbols in the figures.

Show it:

FIG. 1 shows an EUV projection exposure system in meridional section;

FIG. 2 shows a DUV projection exposure system;

FIG. 3 shows a schematic representation of a device according to the invention in interaction with other optical elements;

FIG. 4 is a schematic representation of an optical device with mutually tilted surfaces in a preliminary stage in the embodiment of the invention;

FIG. 5 shows a schematic representation of an optical device with coordinated tilted and/or positioned surfaces for forming an overall surface according to the invention;

FIG. 6 shows a schematic representation of an optical device with coordinately tilted and/or positioned and/or curved surfaces for forming an overall surface according to the invention;

FIG. 7 shows a schematic sectional illustration of a manipulation device under one of the surfaces;

Figure 8 is a schematic sectional view of an embodiment of a curving means beneath one of the surfaces;

Figure 9 is a schematic sectional view of a further embodiment of a curving device under one of the surfaces;

Figure 10 is a schematic plan view of an embodiment of a curving device beneath one of the surfaces;

FIG. 11 shows a schematic sectional illustration of an embodiment of the positioning device; and Figure 12 is a block diagram representation of an embodiment of the present invention

procedure.

The essential components of an EU V projection exposure system 100 for microlithography are described below as an example of a lithography system, initially with reference to FIG. The description of the basic structure of the EUV projection exposure system 100 and its components should not be understood as limiting here.

In addition to a radiation source 102 , an illumination system 101 of the EUV projection exposure system 100 has illumination optics 103 for illuminating an object field 104 in an object plane 105 . In this case, a reticle 106 arranged in the object field 104 is exposed. The reticle 106 is held by a reticle holder 107 . The reticle holder 107 can be displaced via a reticle displacement drive 108, in particular in a scanning direction.

A Cartesian xyz coordinate system is shown in FIG. 1 for explanation. The x-direction runs perpendicularly into the plane of the drawing. The y-direction is horizontal and the z-direction is vertical. In FIG. 1, the scanning direction runs along the y-direction. The z-direction runs perpendicular to the object plane 105.

The EUV projection exposure system 100 includes projection optics 109. The projection optics 109 are used to image the object field 104 in an image field 110 in an image plane 111. The image plane 111 runs parallel to the object plane 105. Alternatively, there is also an angle other than 0° between the object plane 105 and the image plane 111 is possible.

A structure on the reticle 106 is imaged onto a light-sensitive layer of a wafer 112 arranged in the region of the image field 110 in the image plane 111. The wafer 112 is held by a wafer holder 113. The wafer holder 113 can be displaced via a wafer displacement drive 114, in particular along the y-direction. The displacement of the reticle 106 via the reticle displacement drive 108 on the one hand and the wafer 112 on the other hand via the wafer displacement drive 114 can be synchronized with one another.

The radiation source 102 is an EUV radiation source. The radiation source 102 emits in particular EUV radiation 115, which is also referred to below as useful radiation or illumination radiation. The useful radiation 115 has, in particular, a wavelength in the range between 5 nm and 30 nm a DPP ("Gas Discharged Produced Plasma") source. It can also be a synchrotron-based radiation source. The radiation source 102 can be a free-electron laser (FEL). The illumination radiation 115 emanating from the radiation source 102 is bundled by a collector 116 . The collector 116 can be a collector with one or more ellipsoidal and/or hyperboloidal reflection surfaces. The at least one reflection surface of the collector 116 can in grazing incidence ("Grazing Incidence", Gl), i.e. with angles of incidence greater than 45°, or in normal incidence ("Normal Incidence", NI), i.e. with angles of incidence smaller than 45°, with of the illumination radiation 115 are applied. The collector 116 can be structured and/or coated on the one hand to optimize its reflectivity for the useful radiation 115 and on the other hand to suppress stray light.

After the collector 116, the illumination radiation 115 propagates through an intermediate focus in an intermediate focal plane 117. The intermediate focal plane 117 can represent a separation between a radiation source module, comprising the radiation source 102 and the collector 116, and the illumination optics 103.

The illumination optics 103 includes a deflection mirror 118 and a first facet mirror 119 downstream of this in the beam path. The deflection mirror 118 can be a planar deflection mirror or alternatively a mirror with an effect that influences the bundle beyond the pure deflection effect. Alternatively or additionally, the deflection mirror 118 can be designed as a spectral filter, which separates a useful light wavelength of the illumination radiation 115 from stray light of a different wavelength. If the first facet mirror 119 is arranged in a plane of the illumination optics 103 which is optically conjugate to the object plane 105 as a field plane, it is also referred to as a field facet mirror. The first facet mirror 119 includes a multiplicity of individual first facets 120, which are also referred to below as field facets. A few of these facets 120 are shown in FIG. 1 only by way of example.

The first facets 120 can be embodied as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or part-circular edge contour. The first facets 120 can be embodied as planar facets or alternatively as convexly or concavely curved facets.

As is known, for example, from DE 10 2008 009 600 A1, the first facets 120 themselves can each also be composed of a multiplicity of individual mirrors, in particular a multiplicity of micromirrors. The first facet mirror 119 can be embodied in particular as a microelectromechanical system (MEMS system). Reference is made to DE 10 2008 009 600 A1 for details.

The illumination radiation 115 runs horizontally between the collector 116 and the deflection mirror 118, ie along the y-direction.

A second facet mirror 121 is arranged downstream of the first facet mirror 119 in the beam path of the illumination optics 103 . If the second facet mirror 121 in a pupil plane of Illumination optics 103 is arranged, this is also referred to as a pupil facet mirror. The second facet mirror 121 can also be arranged at a distance from a pupil plane of the illumination optics 103 . In this case, the combination of the first facet mirror 119 and the second facet mirror 121 is also referred to as a specular reflector. Specular reflectors are known from US 2006/0132747 A1, EP 1 614 008 B1 and US Pat. No. 6,573,978.

The second facet mirror 121 includes a plurality of second facets 122. In the case of a pupil facet mirror, the second facets 122 are also referred to as pupil facets.

The second facets 122 can also be macroscopic facets, which can have round, rectangular or hexagonal borders, for example, or alternatively facets composed of micromirrors. In this regard, reference is also made to DE 10 2008 009 600 A1.

The second facets 122 can have plane or alternatively convexly or concavely curved reflection surfaces.

The illumination optics 103 thus forms a double-faceted system. This basic principle is also called "Fly's Eye Integrator".

It can be advantageous not to arrange the second facet mirror 121 exactly in a plane which is optically conjugate to a pupil plane of the projection optics 109 .

The individual first facets 120 are imaged in the object field 104 with the aid of the second facet mirror 121 . The second facet mirror 121 is the last beam-forming mirror or actually the last mirror for the illumination radiation 115 in the beam path in front of the object field 104.

In a further embodiment of the illumination optics 103 that is not shown, transmission optics can be arranged in the beam path between the second facet mirror 121 and the object field 104 , which particularly contribute to the imaging of the first facets 120 in the object field 104 . The transmission optics can have exactly one mirror, but alternatively also have two or more mirrors, which are arranged one behind the other in the beam path of the illumination optics 103 . The transmission optics can in particular comprise one or two mirrors for normal incidence (NI mirror, "normal incidence" mirror) and/or one or two mirrors for grazing incidence (GI mirror, "gracing incidence" mirror).

In the embodiment shown in FIG. 1, the illumination optics 103 has exactly three mirrors after the collector 116, namely the deflection mirror 118, the field facet mirror 119 and the pupil facet mirror 121. In a further embodiment of the illumination optics 103, the deflection mirror 118 can also be omitted, so that the illumination optics 103 can then have exactly two mirrors downstream of the collector 116, namely the first facet mirror 119 and the second facet mirror 121.

The imaging of the first facets 120 by means of the second facets 122 or with the second facets 122 and transmission optics in the object plane 105 is generally only an approximate imaging.

The projection optics 109 includes a plurality of mirrors Mi, which are numbered consecutively according to their arrangement in the beam path of the EUV projection exposure system 100 .

In the example shown in FIG. 1, the projection optics 109 include six mirrors M1 to M6. Alternatives with four, eight, ten, twelve or another number of mirrors Mi are also possible. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation 115. The projection optics 109 are doubly obscured optics. The projection optics 109 has an image-side numerical aperture which is greater than 0.5 and which can also be greater than 0.6 and which can be 0.7 or 0.75, for example.

Reflection surfaces of the mirrors Mi can be designed as free-form surfaces without an axis of rotational symmetry. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflection surface shape. Just like the mirrors of the illumination optics 103, the mirrors Mi can have highly reflective coatings for the illumination radiation 115. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

The projection optics 109 has a large object-image offset in the y-direction between a y-coordinate of a center of the object field 104 and a y-coordinate of the center of the image field 110. This object-image offset in the y-direction can approximately as large as a z-distance between the object plane 105 and the image plane 111.

The projection optics 109 can in particular be anamorphic. In particular, it has different image scales βx, βy in the x and y directions. The two image scales βx, βy of the projection optics 109 are preferably at (βx, βy)=(+/−0.25, +/-0.125). A positive image scale ß means an image without image reversal. A negative sign for the imaging scale ß means imaging with image reversal.

The projection optics 109 thus leads to a reduction in the ratio 4:1 in the x-direction, ie in the direction perpendicular to the scanning direction.

The projection optics 109 lead to a reduction of 8:1 in the y-direction, ie in the scanning direction. Other imaging scales are also possible. Image scales with the same sign and absolutely the same in the x and y directions, for example with absolute values of 0.125 or 0.25, are also possible.

The number of intermediate image planes in the x-direction and in the y-direction in the beam path between the object field 104 and the image field 110 can be the same or, depending on the design of the projection optics 109, can be different. Examples of projection optics with different numbers of such intermediate images in the x and y direction are known from US 2018/0074303 A1.

In each case one of the pupil facets 122 is assigned to precisely one of the field facets 120 in order to form a respective illumination channel for illuminating the object field 104 . In this way, in particular, lighting can result according to Köhler's principle. The far field is broken down into a large number of object fields 104 with the aid of the field facets 120 . The field facets 120 generate a plurality of images of the intermediate focus on the pupil facets 122 respectively assigned to them.

The field facets 120 are each imaged onto the reticle 106 by an associated pupil facet 122 in a superimposed manner in order to illuminate the object field 104 . In particular, the illumination of the object field 104 is as homogeneous as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

The illumination of the entrance pupil of the projection optics 109 can be geometrically defined by an arrangement of the pupil facets. The intensity distribution in the entrance pupil of the projection optics 109 can be set by selecting the illumination channels, in particular the subset of the pupil facets that guide light. This intensity distribution is also referred to as an illumination setting.

A likewise preferred pupil uniformity in the area of defined illuminated sections of an illumination pupil of the illumination optics 103 can be achieved by redistributing the illumination channels.

Further aspects and details of the illumination of the object field 104 and in particular the entrance pupil of the projection optics 109 are described below.

The projection optics 109 can in particular have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

The entrance pupil of the projection optics 109 cannot regularly be illuminated exactly with the pupil facet mirror 121 . When imaging the projection optics 109, which telecentrically images the center of the pupil facet mirror 121 onto the wafer 112, the aperture rays often do not intersect in a single point. However, a surface can be found in which the distance between the aperture rays, which is determined in pairs, is minimal. This surface represents the entrance pupil or a surface conjugate to it in position space. In particular, this surface exhibits a finite curvature.

The projection optics 109 may have different positions of the entrance pupil for the tangential and for the sagittal beam path. In this case, an imaging element, in particular an optical component of the transmission optics, should be provided between the second facet mirror 121 and the reticle 106 . With the help of this optical component, the different positions of the tangential entrance pupil and the sagittal entrance pupil can be taken into account.

In the arrangement of the components of the illumination optics 103 shown in FIG. 1, the pupil facet mirror 121 is arranged in a surface conjugate to the entrance pupil of the projection optics 109 . The first field facet mirror 119 is arranged tilted to the object plane 105 . The first facet mirror 119 is tilted relative to an arrangement plane that is defined by the deflection mirror 118 .

The first facet mirror 119 is tilted relative to an arrangement plane that is defined by the second facet mirror 121 .

An exemplary DUV projection exposure system 200 is shown in FIG. The DUV projection exposure system 200 has an illumination system 201, a device called a reticle stage 202 for receiving and precisely positioning a reticle 203, through which the later structures on a wafer 204 are determined, a wafer holder 205 for holding, moving and precisely positioning the wafer 204 and an imaging device, namely projection optics 206, with a plurality of optical elements, in particular lenses 207, which are held in an objective housing 209 of the projection optics 206 via mounts 208.

As an alternative or in addition to the lenses 207 shown, various refractive, diffractive and/or reflective optical elements, including mirrors, prisms, end plates and the like, can be provided.

The basic functional principle of the DUV projection exposure system 200 provides that the structures introduced into the reticle 203 are imaged onto the wafer 204 .

The illumination system 201 provides a projection beam 210 in the form of electromagnetic radiation that is required for imaging the reticle 203 onto the wafer 204 . A laser, a plasma source or the like can be used as the source for this radiation. The radiation is shaped in the illumination system 201 via optical elements in such a way that the projection beam 210 has the desired properties in terms of diameter, polarization, shape of the wave front and the like when it strikes the reticle 203 . An image of the reticle 203 is generated by means of the projection beam 210 and transmitted to the wafer 204 in a correspondingly reduced size by the projection optics 206 . The reticle 203 and the wafer 204 can be moved synchronously, so that areas of the reticle 203 are imaged onto corresponding areas of the wafer 204 practically continuously during a so-called scanning process.

Optionally, an air gap between the last lens 207 and the wafer 204 can be replaced by a liquid medium which has a refractive index greater than 1.0. The liquid medium can be, for example, ultrapure water. Such a structure is also referred to as immersion lithography and has an increased photolithographic resolution.

The use of the invention is not limited to use in lithography systems and also not to use in projection exposure systems 100, 200, in particular also not with the structure described. The invention is nonetheless particularly suitable for lithography systems, in particular projection exposure systems, in particular with the structure described. Furthermore, the invention and the following exemplary embodiments are not to be understood as being restricted to a specific design. The following figures represent the invention only by way of example and in a highly schematic manner.

FIG. 3 shows a schematic representation of a device 1 according to the invention, which has a plurality of optically active surfaces 2, wherein the surfaces 2 can each be tilted by means of a separate, autonomously controllable manipulation device 3 assigned to the surface 2. Here, the manipulation device 3 is set up to also position and/or warp the surface 2, with an overall control device 4 being provided, which controls the manipulation devices 3 in such a way that at least two of the surfaces 2 result in an overall surface 5 in a planned and coordinated interaction.

In the exemplary embodiment illustrated in FIG. 3, the optical device 1 is designed as a facet mirror, preferably as a field facet mirror 119, which directs light emanating from a light source 6 onto at least one target location 7 on a target structure 8, for example a pupil facet 122 of a pupil facet mirror 121, reflected. In particular, it can be provided that a focal point of a surface 2 designed, for example, as a concave mirror should be positioned at the target location.

Furthermore, in the exemplary embodiment of the optical device 1 shown in Figure 3, the overall control device 4 is set up to preferably control the manipulation device 3 in such a way that gaps 9 between adjacent surfaces 2 are reduced by tilting and/or positioning and/or a curvature of the surfaces 2 are.

Furthermore, in the exemplary embodiment of the optical device 1 illustrated in FIG. 3, the overall control device 4 preferably controls the manipulation devices 3 in such a way that the gaps 9 between adjacent surfaces 2 are minimized. In the exemplary embodiment illustrated in FIG. 3, at least part of the surfaces 2 has a reflective layer system formed at least on part of the respective surface 2 .

The surfaces 2 also have a hexagonal or triangular or rectangular, preferably square, shape.

Furthermore, the surfaces 2 have an area of between 0.5 mm ² and 10 mm ² , preferably between 0.9 mm ² and 2 mm ² , particularly preferably 1 mm ² .

FIG. 4 shows a schematic representation of an optical device 1 in which the surfaces 2 are only tilted by the manipulation devices 3 .

FIG. 5 shows a schematic representation of an optical device 1 in which the surfaces 2 are tilted and positioned in a planned and coordinated manner by the manipulation devices 3 and thus result in an overall surface 5 .

In the embodiment of Figure 5, the gaps 9 between adjacent surfaces are reduced.

FIG. 6 shows a schematic representation of an optical device 1 in which the surfaces 2 are tilted and positioned and curved in a planned and coordinated manner by the manipulation devices 3 and thus result in an overall surface 5 .

The surfaces 2 of the optical device 1 can also be tilted and curved (not shown separately) in a planned and coordinated manner by the manipulation devices 3 in order to form an overall surface.

In the exemplary embodiments illustrated in FIGS. 4, 5 and 6, the surfaces 2 and the manipulation devices 3 are arranged on a common base body 17.

In the exemplary embodiment according to FIG. 6, the gaps 9 between adjacent surfaces are minimized, so that the surfaces 2 adjoin one another at least approximately seamlessly.

Figure 7 shows an exemplary embodiment of the surface 2 and the manipulation device 3 assigned to the surface 2.

In the exemplary embodiment illustrated in FIG. 7, the manipulation device 3 has a tilting device 10 in order to rotate the surface 2 relative to an initial alignment of a mean surface normal

11 of the surface 2 to tilt. Furthermore, the manipulation device 3 has a bending device

12 to curve the surface 2. Furthermore, the manipulation device 3 has a Positioning device 13 to raise or lower the surface 2 plane-parallel to a starting position, wherein the tilting device 10 and the curvature device 12 and / or the positioning device 13 are formed as independent devices.

In the exemplary embodiment illustrated in FIG.

In the exemplary embodiment illustrated in FIG. 7, the tilt control devices 14 and the positioning control devices 15 and the curvature control devices 16 are designed independently. In an exemplary embodiment that is not shown, it can be provided that the tilt control devices 14 and the positioning control devices 15 and the curvature control devices 16 are designed as part of the overall control device 4 .

Furthermore, in the exemplary embodiment illustrated in FIG. 7, the surface 2 is designed to reflect light, in particular EUV light.

The surface 2 is arranged on the base body 17 which serves as a common base body 17 for all surfaces 2 of the optical device 1 . Alternatively, the base body 17 can also serve as a basis for only part of the surfaces in order to arrange them.

In the exemplary embodiment of the optical device 1 illustrated in FIG.

In the present exemplary embodiment, the tilting devices 10 and the bending devices 12 and the positioning devices 13 are preferably designed in accordance with the exemplary embodiment of the manipulation device 3 illustrated in FIG.

In the exemplary embodiment illustrated in FIG. 7, the tilting device 10 and the curving device 12 and the positioning device 13 are arranged between the base body 17 and the respective surface 2 .

The curving device 12 is arranged between the surface 2 and the tilting device 10 .

Furthermore, the positioning device 13 is arranged between the tilting device 10 and the base body 17 . In the exemplary embodiment illustrated in FIG. 7, the tilting device 10 assigned to one of the surfaces 2 and the bending device 12 and the positioning device 13 are preferably functionally and/or physically connected to the base body 17 and the respective surface 2 and preferably to one another.

Furthermore, in the exemplary embodiment illustrated in FIG. 7, the tilting device 10 and the bending device 12 and the positioning device 13 are designed using MEMS technology (microelectromechanical system technology).

In the exemplary embodiment, the surface 2 is formed on a surface base body 18, the surface base body 18 preferably having a thickness of 1 to 500 μm.

Figures 8 and 9 show exemplary embodiments of the bending device 12.

The curvature device 12 is in this case formed by at least one stretchable and/or contractible actuator element 19, preferably as a piezoelectric element.

The curvature device 12 is preferably formed by at least two, preferably at least four, actuator elements 19 arranged along at least two axes.

FIG. 8 shows an exemplary embodiment of the curvature device 12, with the actuator elements 19 being arranged at a distance from the surface base body 18 on the side of the surface base body 18 facing away from the surface 2.

In this case, a stiffening element 19a is arranged between the actuator elements 19 and improves a curvature of the surface 2 around a central region of the surface 2 . In this way, for example, the surface 2 can assume the form of a concave mirror.

In particular, in the exemplary embodiment, the stiffening element 19a is used to arrange the bending device 12 on the tilting device 10.

In the exemplary embodiment illustrated in FIG. 8, two actuator elements 19 are arranged in a plane parallel to surface 2 along an axis. The actuator elements 19 and the surface base body 18 are separated from one another and spaced apart in such a way that, for example, a contraction of the actuator elements 19 can lead to a curvature of the surface base body 18 and thus of the surface 2 . Due to the distance, this can be done while largely avoiding a curvature of the actuator elements 19, as a result of which they are exposed to less wear, for example. FIG. 9 shows an exemplary embodiment of the curvature device 12, with the actuator elements 19 being arranged in direct contact on the surface base body 18 on the side of the surface base body 18 facing away from the surface 2.

In the exemplary embodiments of the curvature device 12 illustrated in FIGS. 8 and 9, this is set up in order to create a curvature on the surface 2 of less than 20 1/m, preferably between 0.2 1/m and 20 1/m, preferably between 0. 5 1/m and 4 1/m, in particular between 1 1/m and 2 1/m.

In the exemplary embodiments of the curvature device 12 illustrated in FIGS. 8 and 9, this is also set up to form at least two curvatures on the surface 2 .

Figure 10 shows a plan view of the side of the surface base body 18 facing away from the surface 2.

The four actuator elements 19 are arranged in direct contact on the surface base body 18 on the side of the surface base body 18 facing away from the surface 2 .

The surface base body 18 and the associated surface 2 have a square shape in the exemplary embodiment.

In the exemplary embodiment, the surface 2 is curved along two axes in such a way that at least two radii of curvature of the surface 2 result, with the two axes not coinciding. In the exemplary embodiment, the two axes preferably run at right angles to one another.

In the figures 8, 9 and 10 stretching and contraction directions of the actuator elements 19 are shown by double arrows.

FIG. 11 shows a schematic sectional illustration of an exemplary embodiment of the positioning device 13. In this case, the tilting device 10 is arranged on the positioning device 13 as an example, with the surface base body 18 and the surface 2 being arranged on the tilting device 10.

In the exemplary embodiment illustrated in FIG. 11, the positioning device 13 is formed by a membrane 20 that can be deflected, preferably electrostatically actuated, over a cavity 21 .

A deflection direction of the membrane 20 is shown in FIG. 11 by a double arrow.

The optical device 1 shown in Figures 3 to 11 is particularly suitable for carrying out a method for controlling the optical device 1, which has a plurality of optical has active surfaces 2, each surface 2 being controllable autonomously in order to tilt the surface 2. In the method, the surfaces 2 are tilted and/or positioned and/or curved in such a way that at least two of the surfaces 2 result in the total surface 5 in a planned and coordinated interaction.

The mutually tilted surfaces 2 are positioned and/or curved relative to one another in such a way that gaps 9 between adjacent surfaces 2 tilted relative to one another are reduced, preferably minimized.

In particular, the surfaces 2 that are tilted relative to one another are accordingly positioned and/or curved relative to one another in such a way that gaps 9 between adjacent surfaces 2 that are tilted relative to one another are minimized, as is illustrated in FIG.

Possible configurations of the tilting device 10, which can also be used in the optical device 1, are known from the general prior art. In this regard, reference is made in particular to DE 102015204 874 A1. This document discloses, for example in FIG. Further possible embodiments of tilting devices 10 are described in the publications US Pat. No. 9,013,676 B2 and US Pat. No. 7,538,471 B2.

FIG. 12 shows a block diagram representation of an exemplary embodiment of a method according to the invention.

In a coordination block 30, the tilting and/or the curvature and/or the positioning of those surfaces 2 are planned and coordinated, which should result in the overall surface 5. In a tilting block 31 , a warping block 32 and a positioning block 33 the respective surfaces 2 are tilted and/or curved and/or positioned to an extent specified in the coordination block 30 such that the surfaces 2 result in a total surface 5 in a result block 34 .

In the exemplary embodiment described, the tilting and/or the curvature and/or the positioning of a surface 2 takes place in each case by autonomous devices that can be controlled independently of one another.

Furthermore, each surface has its own control device in order to control the tilting and the curvature and/or the positioning of the respective surface 2 . The overall control device 4 is provided in order to control all surfaces 2 forming the overall surface 5 in such a way that, while maintaining a defined tilting of the individual surfaces 2, the surfaces 2 as a whole are positioned and/or curved in such a way that the gaps 9 between adjacent surfaces tilted relative to one another 2 of the total surface area 5 is reduced, preferably minimized. In the exemplary embodiment of the method described, the surfaces are curved in such a way that the surfaces 2 are each curved along at least two axes in such a way that at least two radii of curvature of the respective surface 2 result.

The method provides for the overall surface 5 to be formed from a plurality of surfaces 2 which are tilted and/or curved and/or shifted in a planned and coordinated manner.

The surfaces 2 are preferably also tilted and/or curved and/or shifted in a coordinated manner in such a way that an at least approximately smooth overall surface 5 is formed. In this case, an at least approximately smooth overall surface has no gaps or sharp edges and minimized gaps 9 between the surfaces 2 .

In the coordination block 30, the tilting and the curvatures and/or the positioning of the surfaces 2 are determined in such a way that in the result block 34 the entire surface 5 is formed in such a way that one or more focus points are formed.

Furthermore, it is provided that the overall surface 5 is shaped in such a way that the position and/or the number of the one or more focal points is changed during use of the device 1 .

To stabilize the optical properties of the overall surface 5, a sensor block 35 is also provided in the exemplary embodiment shown, in which, for example, a wave front originating from the overall surface 5 and/or the tilting and/or the curvature and/or the position is measured. The information recorded in the sensor block 35 is then forwarded to a feedback block 36 in which, based on the information, correction signals and/or setting signals are transmitted for the coordination block 30 and are transmitted to it. In the coordination block, updated commands for controlling blocks 31, 32 and 33 are then determined and forwarded.

The coordination block 30, the tilting block 31, the curvature block 32, the positioning block 33 and the feedback block 36 can therefore be considered as part of an overall control block 37 in which the individual blocks are implemented in a coordinated manner.

The overall control block 37 or individual blocks 30 , 31 , 32 , 33 , 36 of the overall control block can be implemented in the overall control device 4 . Reference List

1 Optical device

2 surface

3 manipulation device

4 overall controller

5 total surface

6 light source

7 destination

8 target structure

9 gap

10 tilting device

11 surface normals

12 curvature device

13 positioning device

14 tilt control device

15 positioning controller

16 curvature control device

17 body

18 surface primitives

19 actuator element

19a stiffening element

20 membrane

21 cavity

30 coordination block

31 tipping block

32 curvature block

33 positioning block

34 result block

35 sensor block

36 feedback block

37 overall control block

100 EUV projection exposure system

101 lighting system

102 radiation source

103 illumination optics

104 object field

105 object level

106 reticle

107 reticle holder 108 reticle displacement drive

109 projection optics

110 field of view

111 image plane

112 wafers

113 wafer holder

114 wafer displacement drive

115 EUV / useful / illumination radiation

116 collector

117 intermediate focal plane

118 deflection mirrors

119 first facet mirror / field facet mirror

120 first facets / field facets

121 second facet mirror / pupil facet mirror

122 second facets / pupil facets

200 DUV projection exposure system

201 lighting system

202 reticle days

203 reticle

204 wafers

205 wafer holder

206 projection optics

207 lens

208 version

209 lens body

210 projection beam

Wed mirror

Claims

Patent Claims:

1. Optical device (1) having a plurality of optically active surfaces (2), the surfaces (2) each being tiltable by means of its own autonomously controllable manipulation device (3) assigned to the surface (2), characterized in that the manipulation device (3) is set up to position and warp the surface (2), an overall control device (4) being provided which controls the manipulation devices (3) in such a way that at least two of the surfaces (2) interact in a planned and coordinated manner give a total surface (5).

2. Optical device (1) having a plurality of optically active surfaces (2), the surfaces (2) each being tiltable by means of its own autonomously controllable manipulation device (3) assigned to the surface (2), characterized in that the manipulation device (3) is set up to position and/or warp the surface (2), with an overall control device (4) being provided which controls the manipulation devices (3) in such a way that at least two of the surfaces (2) in a planned and coordinated interaction result in an overall surface (5), each surface (2) having its own control device (14,15,16) which is set up to tilt and warp and/or position the respective surface (2). control and wherein the overall control device (4) controls all surfaces (2) in such a way that while maintaining a defined tilting of the individual surfaces (2 ) the surfaces (2) are positioned and/or curved overall in such a way that gaps (9) between adjacent surfaces (2) tilted towards one another of the overall surface (5) are reduced, preferably minimized.

3. Optical device (1) according to claim 1 or 2, characterized in that the overall control device (4) controls the manipulation devices (3) such that columns (9) between adjacent, mutually tilted surfaces (2) by positioning and / or a curvature of the surfaces (2) are minimized.

4. Optical device (1) according to one of Claims 1 to 3, characterized in that the manipulation device (3) has a tilting device (10) in order to tilt the surface (2) with respect to an initial alignment of a mean surface normal (11) of the surface (2 ) to tilt, and the manipulation device (3) has a curvature device (12) in order to curve the surface, and/or a positioning device (13) in order to raise or lower the surface (2) in a plane-parallel manner in relation to an initial position, the tilting device ( 10) and the bending device (12) and/or the positioning device (13) are designed as independent devices.

5. Optical device (1) according to one of claims 1 to 4, characterized in that at least some of the surfaces (2) have a reflective layer system formed at least on a part of the respective surface (2).

6. Optical device (1) according to one of claims 4 or 5, characterized in that the curvature device (12) is set up to form at least two curvatures on the surface (2).

7. Optical device (1) according to one of claims 4 to 6, characterized in that the tilting device (10) and/or the bending device (12) and/or the positioning device (13) by means of MEMS technology (microelectromechanical system technology) are trained.

8. Optical device (1) according to one of claims 4 to 7, characterized in that the positioning device (13) is formed by a deflectable, preferably electrostatically actuable, membrane (20) over a cavity (21).

9. Optical device (1) according to one of claims 4 to 8, characterized in that the curvature device (12) is arranged between the surface (2) and the tilting device (10).

10. Optical device (1) according to one of claims 4 to 9, characterized in that the positioning device (13) is arranged on the side facing away from the surface (2) between the tilting device (10) and the base body (17).

11 . Optical device (1) according to one of Claims 1 to 10, characterized in that the surface (2) has a surface area of between 0.5 mm ² and 10 mm ² , preferably between 0.9 mm ² and 2 mm ² , particularly preferably 1 mm ² .

12. Optical device (1) according to claim 1, characterized in that each surface (2) has its own control device (14,15,16), which is set up to tilt and the curvature and / or the positioning of the respective to control the surface (2) and wherein the overall control device (4) controls all surfaces (2) in such a way that, while maintaining a defined tilting of the individual surfaces (2), the surfaces (2) are positioned and/or warped overall in such a way that columns ( 9) between adjacent, mutually tilted surfaces (2) of the overall surface (5) are reduced, preferably minimized.

13. A method for controlling an optical device (1) which has a plurality of optically active surfaces (2), each surface (2) being controllable autonomously in order to tilt the surface (2), characterized in that the surfaces ( 2) are tilted and/or positioned and/or curved in such a way that at least two of the surfaces (2) result in a total surface (5) in a planned and coordinated interaction.

14. The method according to claim 13, characterized in that the mutually tilted surfaces (2) are positioned and/or curved relative to one another in such a way that gaps (9) between adjacent surfaces (2) tilted relative to one another are reduced, preferably minimized.

15. The method according to claim 13 or 14, characterized in that the tilting and/or the curvature and/or the positioning of the respective surface (2) takes place in each case by independent devices that can be controlled independently of one another.

16. The method according to any one of claims 13 to 15, characterized in that while maintaining a defined tilting of the individual surfaces (2), the surfaces (2) are overall positioned and/or curved in such a way that gaps (9) between adjacent ones are tilted towards one another Surfaces (2) of the total surface (5) are reduced, preferably minimized.