DE102024203031A1 - Device, holding device, arrangement, system and method for holding an optical element; lithography system - Google Patents

Abstract

The invention relates to a device (1) for holding an optical element (2), in particular an optical element of a lithography system, having a holding point (5) for connection to the optical element (2). The holding point (5) is connected to a carrier (3). According to the invention, the carrier (3) has at least two rod legs (3a) and a connecting piece (15), wherein the connecting piece (15) is arranged between the holding point (5) and an upper end (9a) of the rod legs (3a) and connects the rod legs (3a) to one another. The rod legs (3a) converge towards the holding point (5) at an acute angle (6), wherein a virtual intersection point (7) in the extension of the rod legs (3a) lies beyond the holding point (5).

Description

The invention relates to a device for holding an optical element, in particular an optical element of a lithography system.

The invention also relates to a holding device for holding an optical element, in particular an optical element of a lithography system, comprising at least a first and a second device according to the invention.

The invention also relates to an arrangement for holding an optical element, in particular an optical element of a lithography system, comprising at least six devices according to the invention or three holding devices according to the invention.

The invention further relates to a system comprising an optical element, in particular an optical element of a lithography system, and at least six devices according to the invention or three holding devices according to the invention for holding the optical element.

The invention also relates to a method for holding and in particular for positioning and/or aligning an optical element, in particular an optical element of a lithography system.

The invention further relates to a lithography system, in particular a projection exposure system for semiconductor lithography, comprising an illumination system with a radiation source and an optics which has at least one optical element.

Optical elements require a suitable holder to fix, hold or store them in an optical system and to be able to move and/or tilt them as needed. Even during installation, uneven mounting or contact surfaces, manufacturing tolerances, angular or positioning errors or thermal expansion differences between the optical element and its surroundings can affect the holder or the optical element. Thermal expansion differences between the optical element and its surroundings can also be caused by light absorption during operation. If positioning and/or alignment is necessary or desired, actuators are used which exert additional forces. During installation, in operation, as well as during positioning and/or alignment, unwanted forces and moments are transferred to the optical element, which lead to deformation of the optical element and/or an optical surface of the optical element. These deformations can impair the functionality of the optical element, especially when high precision in the beam path and/or beam profile is required, such as for the best possible imaging quality and the lowest possible aberrations in semiconductor lithography.

For many applications, particularly in high-performance optics, optical elements must be able to move at least translationally in lateral and axial directions and rotationally around the radial, tangential, and axial axes. Deformations of the optical elements or optical surfaces can occur in this process. Such deformations typically arise from parasitic forces and/or moments or parasitic loads that occur as an undesirable or passive side effect of the desired active positioning and/or alignment of the optical element. This is particularly due to the fact that positioning mechanisms for moving the optical elements are constructed from spring joints, which generate deformation forces and torques during their joint movement and thus during movement of the positioning mechanism. Such parasitic loads are at least partially absorbed or intercepted by the optical element and can therefore unintentionally change the shape of the optical element. Introduced radial moments and tangential moments are of particular importance in this case.

In addition to positioning and/or aligning the optical element, the mount also performs a fundamental holding function. In this regard, vibrations also play a crucial role, which are generally undesirable and should be minimized, just like deformations of the optical element, to achieve the best possible image quality and prevent optical artifacts.

Various devices for holding, storing, positioning and/or aligning optical elements are known from the prior art. Such devices are also known which are designed to partially reduce undesirable deformations of the optical element.

In a basic form, a device for holding, positioning and/or aligning optical elements may comprise a deformation decoupling device that mechanically decouples two parts of the holder.

For example, the EP 1 028 342 A1 A device for tilting an object about at least one axis, in particular an optical element such as a lens, wherein the object is supported by an inner ring and connected to a mount or an outer ring via at least three bearing points. Couplings, in particular support couplings, which can be designed as solid-state joints, are provided, which decouple the object or the inner ring from its mount or the outer ring in terms of deformation.

Similarly, in the WO 2006/000352 A1 a positioning unit for an optical element in a microlithographic projection exposure system with an inner ring and with an outer mount is shown, which has movable intermediate elements or intermediate parts, which are preferably designed as solid-state joints in the form of leaf spring-like levers or leaf springs.

From the US 5 986 827 A A known device for optics is one in which the optical element is supported at three points by a bending mechanism or bipod with two V-shaped supports or bending legs. The bending legs have joints or leaf bending joints at their ends to prevent excessive restriction and thus deformation of the mounted optics. Adjustability is ensured by separate levers.

The joints are intended to make the bending legs flexible against translation and tilting, so that the legs primarily transmit forces in their longitudinal direction to the optical element. This can partially prevent parasitic radial torques. However, deformations of the joints, due to coupling stiffnesses, are at least partially transmitted to the optical element, which then deforms unintentionally. The disadvantageous deformation mechanisms include, above all, but not exclusively, tangential torques during a transverse displacement of the support point perpendicular to the longitudinal axis. These disadvantages also apply to other solutions with state-of-the-art bipod mounts. Regarding the US 5 986 827 A In particular, the increased space requirement due to the additional levers for adjustment is a disadvantage.

The aforementioned solutions have in common that they feature two-part mounts with an inner and an outer ring. However, the weight, unfavorable natural frequencies, high resonance amplitudes, and the dual-mass oscillator structure with multiple inertial elements have proven to be particularly disadvantageous.

The DE 10 2018 200 181 A1 discloses a kinematics system for the guided movement of a component of a projection exposure system, wherein the optical element is mounted directly on the adjustment units or bipods to avoid the aforementioned vibration-dynamic problems. The influence of the parasitic forces and torques acting on the optical element during adjustment of the bipods is reduced by aligning the origin of the principal axis system of the stiffness matrix of the kinematics or bipods with the support points on the optical component. This is achieved by a crossed arrangement of bipod legs and reduces the parasitic loads on the mirror.

Although parasitic tangential torques and the resulting deformations are reduced by this solution, the kinematics of the DE 10 2018 200 181 A1 A comparatively large installation space requirement below, above, and to the sides of the support point, and projections on the optical element are required for connection to the kinematics. Furthermore, due to the indirect force transmission and the tortuous force flow, only a comparatively low level of rigidity can be achieved. This, along with the relatively soft connection, can lead to vibration dynamic problems.

The present invention is based on the object of creating a device for holding an optical element which is improved over the prior art and in particular minimizes unwanted deformations of the optical element.

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

The present invention is also based on the object of creating a holding device for holding an optical element which is improved over the prior art and in particular minimizes unwanted deformations of the optical element.

According to the invention, this object is achieved by a holding device having the features mentioned in claim 15.

The present invention is also based on the object of creating an arrangement for holding an optical element which is improved over the prior art and in particular minimizes unwanted deformations of the optical element.

According to the invention, this object is achieved by an arrangement having the features mentioned in claim 18.

The present invention is further based on the object of creating a system with an optical element which is improved over the prior art and in particular enables an improved mounting of the optical element or minimizes unwanted deformations of the optical element.

According to the invention, this object is achieved by a system having the features mentioned in claim 20.

The present invention is also based on the object of providing a method for holding and in particular for positioning and/or aligning an optical element which is improved over the prior art and in particular minimizes unwanted deformations of the optical element.

According to the invention, this object is achieved by a method having the features mentioned in claim 22.

The present invention is further based on the object of creating a lithography system which has optical elements which are held while avoiding the disadvantages of the prior art, in particular while minimizing unwanted deformations of the optical element.

According to the invention, this object is achieved by a lithography system having the features mentioned in claim 23.

The device according to the invention for holding or supporting an optical element, in particular an optical element of a lithography system, has a holding point for connection to the optical element. The holding point is connected to a carrier. According to the invention, the carrier has at least two rod legs and a connecting piece, wherein the connecting piece is arranged between the holding point and an upper end of the rod legs facing the holding point and connects the rod legs to one another. Furthermore, according to the invention, the rod legs converge towards one another at an acute angle in the direction of the holding point, wherein a virtual intersection point lies in the extension of the rod legs beyond the holding point.

The device according to the invention is advantageously suitable for holding or supporting optical elements under minimal parasitic loads. The internal mobility of the device can passively compensate for, for example, angular or positional errors, thermal expansion differences between the optical element and its surroundings or the holder. Compared to the prior art, hardly any deformation of the optical element occurs, in particular significantly less deformation due to tangential torques during a transverse displacement of the support point perpendicular to a longitudinal axis of the rod legs. Further advantages include direct force guidance, high rigidity and low compliance in the longitudinal direction, low coupling stiffness, and a low tendency toward vibrations and resonances. In the context of lithography systems, this leads to significantly improved image quality, since an optical element held or supported with such reduced deformation experiences little to no image errors caused by external influences. An additional advantage Compared to state-of-the-art solutions with a tendency towards poorer deformation reduction, the device according to the invention has a comparatively low installation space requirement.

The device can also be designed, in particular, to align and/or position the optical element, or to move it in a guided manner. For this purpose, the rod legs can, for example, be movable. Thus, the present invention can achieve the object of creating a device for positioning and/or aligning an optical element that minimizes unwanted deformation of the optical element.

The support point at least partially supports the optical element. The optical element is secured to the support point. The support point can be designed, in particular, as a holder or a holding device. The optical element and the device or carrier can be connected by the support point. The connection can, in particular, also be formed by additional elements between the carrier or the connecting piece and the support point.

The relative position of the rod legs, which are preferably coupled to one another by the connecting piece and whose position is therefore interdependent, can vary. Additional elements can be arranged between the rod legs and the connecting piece. In particular, the support can comprise additional elements.

Depending on the desired direction of action of the device, the plane of the acute angle between adjacent rod legs can be aligned, in particular, tangentially or radially to the optical element or to an optical surface or to an optical surface of the optical element. Within the scope of the invention, the optical surface can be, in particular, the center plane of a lens or the surface or mirror surface of a mirror. However, the plane of the acute angle can also be arbitrarily different or spatially oriented.

The phrase “beyond the holding point” refers to a position of the virtual intersection point on an opposite side of the optical element compared to the rod legs.

In particular, the rod legs converge toward the stop point on the optical element in such a way that at the stop point or at the level of the stop point, a distance remains between the rod legs or the virtual extensions of the rod legs, since, according to the invention, the virtual intersection point lies beyond the stop point. The stop point, in the sense of the invention, is not a point at which the rod legs converge or intersect; rather, the stop point has an extension such that the rod legs can converge toward the stop point and are preferably fixed thereto, but do not intersect at the stop point.

The virtual intersection point is also the instantaneous center of rotation of the rod legs or the connecting piece during a relative movement of the rod legs to each other.

The advantages of the device according to the invention arise primarily from the fact that the device, by arranging at least two rod legs which are movable relative to one another and do not run parallel, can compensate for parasitic forces and/or moments which would otherwise be absorbed by the optical element and deform it, by means of a rotation or counter-tilting or pivoting movement of the connecting piece around the virtual intersection point or instantaneous center of rotation.

Typically, several devices according to the invention are used together to hold the optical element. In particular, two devices according to the invention can together form a bipod or a holding device. The two devices can form the legs of the bipod. In contrast to the prior art, these are not formed from a compact and essentially immobile piece or from a single rod in a middle section of the legs, but are movable within themselves, as described above. Preferably, three such bipods or holding devices or even six individual devices are used for the positioning and/or alignment of an optical element. In particular, several holding points to which the optical element is fixed and which jointly support the optical element can be provided.

Such an embodiment of the invention has proven to be particularly suitable in which a head joint device is provided, wherein the head joint device is arranged between the connecting piece and the holding point.

The head joint device can connect the support or the connecting piece to the holding point.

Furthermore, the head joint device preferably provides tilting mobility of the device at the holding point.

The support may have a support foot, wherein the support foot is arranged at a lower end of the rod legs facing away from the holding point and connects the rod legs to one another.

The support foot supports the wearer at least partially.

The support foot preferably lies on a longitudinal axis of the device.

Additional elements can be arranged between the support base and the lower end of the rod legs.

Instead of the support base, the lower end of the rod legs or the elements attached to them can also be connected by a common support surface in the environment or directly to the fixed world.

Preferably, the carrier is movable by an actuator for targeted positioning and/or alignment of the optical element, wherein the rod legs of the carrier are movable jointly by the actuator, preferably at least along a longitudinal axis of the device.

As a result, the device is also advantageously suitable for positioning and/or aligning or moving optical elements in a guided manner under minimal parasitic loads.

It has proven advantageous if the rod legs can be moved in any direction, preferably at least along one longitudinal axis of the device. Further preferably, the rod legs can also be moved together in a second direction.

The carrier may optionally also have one actuator per rod leg, which are arranged and designed such that the rod legs can be moved synchronously or together.

When the actuator moves the rod legs or the entire support together, the rod legs of the device can move simultaneously in at least approximately the same direction. The relative position of the rod legs can change, as previously described.

For the positioning and/or alignment of the optical element with at least one actuator, the rod legs can in particular have a fixed length or a variable length.

The actuator can be connected or operatively connected to the support base and/or formed integrally with the support base.

In particular, the actuator can be designed to be non-positively, positively and/or materially connected to the support foot.

The actuator is preferably designed to move or displace the support base and/or the support. Furthermore, the actuator is preferably movable or displaceable in multiple spatial directions.

In a preferred embodiment of the invention, the carrier has a compensating element, wherein the compensating element is arranged and designed such that the position of the rod legs relative to one another can be changed in order to reduce deformations of the optical element by means of the interaction of the rod legs, the compensating element and the connecting piece in order to counteract a tilting of the holding point relative to the optical element.

The compensating element can be part of the support.

The head joint device, together with the rod legs, the compensating element and the connecting piece for reducing deformations of the optical element, can contribute to the tilting mobility of the device.

In particular, the kinematics consisting of the rod legs, the connecting piece, and the compensating element, or the rod kinematics, should be able to act or move perpendicular to a longitudinal axis of the device. The kinematics should preferably exhibit high rigidity along the longitudinal axis of the device.

The virtual intersection point or instantaneous center of rotation of the rod legs or the connecting piece is also the instantaneous center of rotation of the rod kinematics.

Deformations of the optical element can be reduced by at least partially compensating for forces and/or moments acting unintentionally on the support point. In particular, deformations of the optical element can be reduced by at least partially compensating for parasitic torques acting on the support point, which can be induced by forces exerted perpendicular to a longitudinal axis of the device for transverse displacement of the support point. In this case, tilting of the support point relative to the optical element is counteracted by the interaction of the rod legs, the compensating element, and the connecting piece. The head joint device can also contribute to this, particularly through its tilting mobility.

Preferably, the following equation (1), which describes the relationship between the stiffnesses of the rod legs, the compensating element and the head joint device, should be fulfilled as well as possible: $$\begin{array}{l}0=n_S{z}_B\{\left[C_{S,rot,n}{\text{ sin}}^2{\beta }_S+C_{S,rot,q}\left(1+{\text{cos}}^2{\beta }_S\right)\right]\left[C_{S,n}{\text{sin}}^2{\beta }_S+C_{S,q}\left(1+{\text{cos}}^2{\beta }_S\right)\right]+\\ \frac{{\text{sin}}^2{\beta }_S{\left(z_P-z_S\right)}^2}{{\text{cos}}^2{\beta }_S}\left[C_{S,n}{C}_{S,q}+C_{S,q}^2{\text{sin}}^2{\beta }_S\right]\}+2C_{B,rot,q}\left\{C_{S,n}{z}_P{\text{ sin}}^2{\beta }_S+C_{S,q}\left(2z_S-z_P{\text{ sin}}^2{\beta }_S\right)\right\}\end{array}$$

Here, z _B < 0 is the z-position of the head joint device, z _S < 0 is the z-position of the rod legs, in particular the point of the principal axis stiffness of a rod leg at which no coupling stiffness occurs and which, in the case of a completely symmetrically constructed rod leg, lies at the intersection point of the symmetry planes, z _P is the z-position of the virtual intersection point of the rod legs or the instantaneous center of rotation of the rod kinematics, n _S is the number of rod legs of the rod kinematics, β _S is the angle of the rod legs to the longitudinal axis of the rod kinematics, C _B,rot,q is the tilting stiffness of the head joint device, C _{S ,n} is the normal stiffness of a rod leg including any compensation element, C S,q is the transverse stiffness of a rod leg including any compensation element, C _S,rot,n is the torsional stiffness of a rod leg including any compensation element and C _S,rot,q is the tilting stiffness of a rod leg including any compensation element. Compensation element.

The angle of the rod legs to the longitudinal axis of the rod kinematics (β _S ) is preferably half the acute angle between the rod legs, so that the rod legs are arranged symmetrically around the longitudinal axis of the rod kinematics.

It may be advantageous if the compensating element is designed as an upper joint device which is arranged at the upper end of the rod legs and connects the rod legs in an articulated manner to the connecting piece, and/or the compensating element is designed as a lower joint device which is arranged at the lower end of the rod legs and connects the rod legs in an articulated manner to the support foot of the device and/or the actuator.

The rod legs are coupled to each other, preferably by the connecting piece, so that the position of the rod legs is dependent on each other.

In this case, a tilting of the support point relative to the optical element can be compensated by a counter-tilting of the rod kinematics, whereby the position of the rod legs relative to each other can also change. The upper joint device and/or the lower joint device are preferably designed to allow a compensating movement of the rod legs relative to each other. In particular, the upper joint device can cooperate with the connecting piece and/or the head joint device.

It should be noted that the articulated connection of the rod legs to the connecting piece is designed such that, according to the invention, the virtual intersection point in the extension of the rod legs lies beyond the stop point. In particular, a distance remains between the rod legs or the virtual extensions of the rod legs at the connecting piece or at the stop point. Furthermore, the distance between the rod legs at the lower end of the rod legs or at the support base is in particular greater than the distance at the upper end of the rod legs or at the connecting piece or at the stop point.

The upper joint device and/or the lower joint device can each have at least one joint.

Preferably, the at least one joint is a leaf spring or a leaf spring joint. The advantages of leaf spring joints include comparatively high rigidity in the rod direction or longitudinal direction of the device, the absence of bearing play, and negligible travel hysteresis in the range of elastic deformation. However, the joint can also be a wire joint or another joint. A wire joint can be advantageous for simultaneous bendability of the joint around multiple axes.

It may be advantageous if the rod legs are rigid, especially in the axial direction.

The rod legs are at least partially or partially rigid.

Especially in combination with an upper joint device, it has proven particularly suitable if the rod legs are stiff or rigid in the axial direction.

The rod legs can be made of steel, especially corrosion-resistant or stainless steel, other metals or ceramics.

It can also be advantageous if the rod legs are flexible, especially in the radial or transverse direction.

The rod legs are at least partially or sectionally flexible.

In particular, it may also be advantageous for the rod legs to be rigid in some sections and flexible in others. In particular, the flexible sections can provide mobility similar to that of the upper and/or lower joints.

It can be provided that the device has two, three or four rod legs, wherein the rod legs are arranged conically.

If necessary, more than two, in particular more than four, rod legs can be provided, whereby the design of the device such that exactly two, three or four rod legs are provided has proven to be particularly suitable.

Preferably, adjacent rod legs converge at an acute angle. The lower ends of the rod legs are preferably evenly distributed in a circle.

Preferably, all rod legs of the device meet at a common virtual intersection point in their extension. The virtual intersection point of the rod legs can be considered the tip of the cone formed by the rod legs.

However, it is also possible for only two of the rod legs, which are arranged mirror-symmetrically to the longitudinal axis of the device, to converge at a common virtual intersection point. Additional rod legs can be arranged, in particular, in a plane perpendicular to the plane spanned by the first two rod legs, mirror-symmetrically to the longitudinal axis of the device and converge at a second common virtual intersection point.

If the rod legs are provided with an upper and a lower joint device, it can be provided that the virtual intersection point is formed from the extensions of the connecting lines between the lower and upper joint devices, whereby the connecting elements between the lower and upper joint devices can deviate in orientation from this connecting line.

It may also be provided that the extension of the rod legs, by which the virtual intersection point is determined, in particular if the rod legs are not linear, is determined by a connecting straight line between the lower and the upper end of the rod legs.

It has also proven particularly suitable if the head joint device is arranged directly at the holding point.

In particular, the head joint device may preferably be arranged as close as possible to the holding point so that no other elements are in between.

It is particularly advantageous if the upper joint device and/or the lower joint device has a plurality of joints.

Furthermore, the head joint device can also have a plurality of joints.

If the upper joint device, the lower joint device and/or the head joint device has a plurality of joints, it is particularly advantageous if the joints are designed as leaf springs or leaf spring joints.

The joints can be arranged in different planes, viewed in the axial direction of the rod legs or along the longitudinal axis of the device. The joints can, in particular, be arranged and configured such that the joint or joints arranged in a first plane allow deflection in a first direction, and the joint or joints arranged in a second plane allow deflection in a second direction orthogonal thereto, wherein the two directions extend in one plane, and the plane or plane preferably extends orthogonally to the longitudinal axis of the device. Intermediate elements can be provided between the planes.

Preferably, first joints of the upper joint device are fixed to the connecting piece, which are each connected to the upper end of one of the rod legs or to an intermediate element of the upper joint device.

A plurality of first joints may be provided. In addition, a plurality of intermediate elements may also be provided if necessary. However, preferably, two or four first joints and, accordingly, two or four first intermediate elements are provided.

The first joints can be advantageously connected to the upper end of one of the rod legs, in particular when the device has exactly two rod legs.

The upper joint device preferably has two first joints. However, four first joints can also be provided, especially if the device has exactly four rod legs. It has proven particularly suitable to provide two or four intermediate elements.

Further preferably, second joints of the upper joint device are fixed to the intermediate elements, which are each connected to the upper end of one of the rod legs.

This embodiment of the invention is particularly suitable when the device has exactly four rod legs. The upper joint device preferably has four second joints.

Analogous to the previously described embodiments of the upper joint device for a device with exactly two rod legs, in particular having two first joints, or with exactly four rod legs, in particular having two or four first joints, two or four intermediate elements, and four second joints, upper joint devices for more than four rod legs can also be constructed. Furthermore, other numbers of first joints, intermediate elements, second joints, and rod legs can also be combined.

Furthermore, it has proven particularly suitable if, viewed in the axial direction of the rod legs, at least two adjacent joints of the upper joint device are oriented rotated by 90° to each other, wherein the joints are in particular the first joints and the second joints.

In this case, joints on the same level of the upper joint device, in particular the first joints to each other or the second joints to each other, are preferably equally oriented or not rotated relative to each other.

Analogously, it may be advantageous if the head joint device has at least two joints on different levels, which are oriented at 90° to each other.

It should be noted that in the aforementioned variants or combinations of the aforementioned variants, at least one joint of the head joint device can be oriented rotated by 90° relative to the first joints and/or to the second joints, but can also be oriented in the same way.

The lower joint device can be provided either in addition to or independently of the upper joint device.

The lower joint device can be constructed analogously to one of the previously described embodiments of the upper joint device.

Preferably, the joints of the lower joint device are designed as leaf springs or leaf spring joints.

In this case, first joints of the lower joint device can be fixed between the support foot or the actuator and the lower end of one of the rod legs or an intermediate element of the lower joint device, wherein second joints of the lower joint device can be fixed to the intermediate element of the lower joint device, which are each connected to the lower end of one of the rod legs.

The first joints of the lower joint device can preferably be oriented rotated by 90° to the second joints of the lower joint device.

The compensating element can be formed at least partially by the lower joint device.

Alternatively or in addition to the upper joint device and/or the lower joint device, the compensating element can be formed at least partially by the rod leg, wherein the rod leg can be made of a flexible material. In this context, the virtual intersection point can refer to the intersection point of straight lines through the respective upper and lower ends of the rod legs.

The head joint device, the connecting piece, the upper joint device, the rod legs, the lower joint device and/or the support foot can be at least partially monolithic.

It can be advantageous if the cross-section of the rod legs is square or rectangular.

This ensures optimal use of the fixture's cross-section, especially when the fixture has exactly four rod legs. Furthermore, it achieves high rigidity in the rod direction or in the longitudinal direction of the fixture, which has a beneficial effect on the fixture's holding properties.

It has proven advantageous if the acute angle between the rod legs is less than 30°, preferably less than 15°, more preferably less than 5°, particularly preferably less than 2°.

It can be particularly advantageous if the virtual intersection point in the extension of the rod legs is at least half as far, preferably at least twice as far, particularly preferably at least four times as far, beyond the stopping point as the rod legs are long.

In a preferred embodiment, the rod legs are between 50 mm and 300 mm long, particularly preferably between 100 mm and 150 mm long.

It should be noted that the size of the acute angle, the distance of the virtual intersection point to the holding point and the length of the rod legs depend on each other and are preferably chosen to match each other.

The present invention also relates to a holding device for holding an optical element, in particular an optical element of a lithography system, at least comprising a first device according to the invention and a second device according to the invention, wherein the first device and the second device converge towards one another in the direction of a common holding point on the optical element.

The holding device can in particular also be a bipod or be referred to as a bipod.

The first device and the second device are, in particular, devices with one or more features according to the preceding description. The advantages arise analogously to those already described.

The first device and the second device converge towards each other in a V-shape at an angle in the direction of the optical element.

At the level of the common support point, a gap can remain between the first device and the second device, or between virtual extensions of the first device and the second device. The common support point can, in particular, be designed as a common holder or holding device.

It can be advantageous if the first device and the second device form at least approximately a right angle to each other. This ensures the greatest possible stability of the holding device or bipod. Furthermore, the right angle prevents feedback between the devices during a movement, for example, during a displacement actively induced by an actuator, of at least one of the two devices.

In this case, an approximately right angle can in particular be an angle between 80° and 100°, preferably an angle between 85° and 95°, more preferably an angle between 88° and 92°, particularly preferably an angle of exactly 90°.

The plane of the holding device, formed by the V-shape of the first device and the second device, which converge at an angle, is preferably perpendicular to the optical element or the optical surface of the optical element. However, the plane of the holding device can also be oriented differently.

In an advantageous further development of the invention, it can be provided that an actuator of the first device for a targeted positioning and/or alignment of the optical element is arranged and designed in such a way to displace a first support foot of the first device, and/or an actuator of the second device for a targeted positioning and/or alignment of the optical element is arranged and designed in such a way to displace a second support foot of the second device, in each case preferably at least along a longitudinal axis of the first device or the second device, in particular on the plane defined by the longitudinal axes of the first device and the second device.

In this further development, at least one of the two devices has an actuator, so that the rod legs of the respective device can be moved together. In particular, the first device and/or the second device can have an actuator. Preferably, both the first support foot and the second support foot are movable.

It can be advantageous if the respective support foot can be moved in exactly two or exactly three spatial directions.

In particular, the actuator of the first device can be arranged and designed to displace the first support foot along the longitudinal axis of the first device and/or in the direction of the second support foot, and/or the actuator of the second device can be arranged and designed to displace the second support foot along the longitudinal axis of the second device and/or in the direction of the first support foot.

The expression “in the direction of the first or second support foot” includes both a displacement towards the first or second support foot and a displacement away from the first or second support foot.

The adjustment of the holding device or the bipod using at least one actuator can be carried out, for example, in accordance with the DE 10 2018 200 178 A1 the applicant.

The present invention also relates to an arrangement for holding an optical element, in particular an optical element of a lithography system, comprising at least six devices according to the invention or three holding devices according to the invention.

The arrangement according to the invention can also be suitable in particular for positioning and/or aligning the optical element.

The devices or holding devices are, in particular, devices or holding devices with one or more features according to the preceding description. The advantages arise analogously to those already described.

Preferably, the arrangement comprises exactly six devices according to the invention or exactly three holding devices according to the invention. As a rule, this sufficiently defines all degrees of freedom for positioning and/or aligning an optical element, if this is provided in addition to the holding function.

Mixtures of devices and holding devices are possible, in particular such that a total of preferably exactly six devices are present, wherein, if appropriate, two devices each can form a holding device.

According to the invention, it can also be provided, in particular, that the arrangement comprises, for example, four devices according to the invention and one holding device according to the invention, wherein the holding device comprises two of the total of six provided devices. Further combinations are analogously possible.

It should be noted that if there are more than six devices, more than three holding devices can be formed by the devices.

The combination of at least six fixtures or three holding devices ensures stable support of the optical element while simultaneously exploiting the degrees of freedom for optional positioning and/or alignment of the optical element. Combining exactly six fixtures or exactly three holding devices into a hexapod has proven particularly advantageous.

It may be advantageous if the devices and/or the holding devices are arranged at least approximately evenly distributed along an outer edge region of the optical element. This increases the stability of the arrangement.

In this case, the devices and/or the holding devices are to be regarded as being arranged at least approximately uniformly distributed on the outer edge region of the optical element, in particular if the respective position of the devices and/or the holding devices deviates by no more than 10%, preferably no more than 5%, more preferably no more than 2%, from their position in the case of a completely uniform distribution.

The holding devices can, in particular, be aligned such that the V-shaped plane formed by the first device and the second device, which converge at an angle to each other, is arranged tangentially to an edge of the optical element. However, the planes of the holding devices can also be aligned differently.

The present invention also relates to a system comprising an optical element, in particular an optical element of a lithography system, and at least six devices according to the invention or three holding devices according to the invention for holding the optical element.

In particular, the positioning and/or alignment of the optical element can also be provided.

The devices or holding devices are, in particular, devices or holding devices with one or more features according to the preceding description. The advantages arise analogously to those already described.

The number and arrangement of the device according to the invention or the holding device according to the invention within the system can preferably be selected as already described with regard to the arrangement according to the invention. It may be particularly suitable if the system according to the invention has six devices or three holding devices. If necessary, two devices can also form a holding device.

The optical element may be a mirror or a lens. In particular, it may be a mirror or a lens of a lithography system.

The present invention also relates to a method for holding and in particular for positioning and/or aligning an optical element, in particular an optical element of a lithography system, wherein the optical element is held and in particular positioned and/or aligned with at least one device according to the invention and/or a holding device according to the invention or an arrangement according to the invention.

The devices, holding devices, or arrangement are, in particular, devices, holding devices, or an arrangement with one or more features according to the preceding description. The advantages arise analogously to those already described.

The present invention further relates to a lithography system, in particular a projection exposure system for semiconductor lithography, comprising an illumination system with a radiation source and an optical system which has at least one optical element, wherein the optical element is held by at least one device according to the invention and/or a holding device according to the invention or an arrangement according to the invention.

The optical element can in particular also be positioned and/or aligned by at least one device according to the invention and/or a holding device according to the invention or an arrangement according to the invention.

The devices, holding devices, or arrangement are, in particular, devices, holding devices, or an arrangement with one or more features according to the preceding description. The advantages arise analogously to those already described.

Lithography systems can in particular be projection exposure systems for semiconductor lithography with EUV (extreme ultraviolet) light and/or with DUV (deep ultraviolet) light.

In these and related application areas, a stable and shake-free mount, as well as, if necessary, a stable and shake-free positioning and precise alignment of optical elements and the simultaneous avoidance of deformations of the optical elements are of particular importance in order to achieve high imaging quality without aberrations and thus to be able to produce high-quality structures, in particular semiconductor structures.

Features described in connection with one of the subject matters of the invention, namely the device according to the invention, the holding device according to the invention, the arrangement according to the invention, the system according to the invention, the method according to the invention, or the lithography system according to the invention, can also be advantageously implemented for the other subject matters of the invention. Likewise, advantages mentioned in connection with one of the subject matters of the invention can also be understood to relate to the other subject matters of the invention.

It should also be noted that terms such as "comprising," "having," or "with" do not exclude other features or steps. Furthermore, terms such as "a" or "the," which refer to a singular number of steps or features, do not exclude a plurality of features or steps—and vice versa.

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

It should be noted that terms such as “first” or “second” etc. are used primarily for reasons of distinguishing between respective device or process features and are not necessarily intended to indicate that features are mutually dependent or related to one another.

In the following, embodiments of the invention are described in more detail with reference to the drawing.

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

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

• 1 eine EUV-Projektionsbelichtungsanlage im Meridionalschnitt;
• 2 eine DUV-Projektionsbelichtungsanlage;
• 3 eine prinzipmäßige Ansicht einer Ausführungsform der erfindungsgemäßen Vorrichtung zur Halterung eines optischen Elements;
• 4 eine weitere prinzipmäßige Ansicht der in 3 gezeigten Ausführungsform der erfindungsgemäßen Vorrichtung zur Halterung eines optischen Elements;
• 5 eine prinzipmäßige Ansicht einer Ausführungsform der erfindungsgemäßen Halteeinrichtung zur Halterung eines optischen Elements;
• 6 eine prinzipmäßige Ansicht einer Ausführungsform der erfindungsgemäßen Anordnung sowie des erfindungsgemäßen Systems zur Halterung eines optischen Elements;
• 7 eine prinzipmäßige Ansicht einer weiteren Ausführungsform der erfindungsgemäßen Halteeinrichtung zur Halterung eines optischen Elements;
• 8 eine prinzipmäßige Ansicht einer weiteren Ausführungsform der erfindungsgemäßen Halteeinrichtung zur Halterung eines optischen Elements;
• 9 eine prinzipmäßige Ansicht einer weiteren Ausführungsform der erfindungsgemäßen Halteeinrichtung zur Halterung eines optischen Elements; und
• 10 eine prinzipmäßige Ansicht einer weiteren Ausführungsform der erfindungsgemäßen Halteeinrichtung zur Halterung eines optischen Elements.

They show:

• 1 an EUV projection exposure system in meridional section;
• 2 a DUV projection exposure system;
• 3 a schematic view of an embodiment of the device according to the invention for holding an optical element;
• 4 another principled view of the 3 shown embodiment of the device according to the invention for holding an optical element;
• 5 a schematic view of an embodiment of the holding device according to the invention for holding an optical element;
• 6 a schematic view of an embodiment of the arrangement according to the invention and of the system according to the invention for holding an optical element;
• 7 a schematic view of a further embodiment of the holding device according to the invention for holding an optical element;
• 8 a schematic view of a further embodiment of the holding device according to the invention for holding an optical element;
• 9 a schematic view of a further embodiment of the holding device according to the invention for holding an optical element; and
• 10 a schematic view of a further embodiment of the holding device according to the invention for holding an optical element.

In the following, with reference to 1 The essential components of an EUV projection exposure system 100 for microlithography are described as an example of a lithography system. The description of the basic structure of the EUV projection exposure system 100 and its components is not intended to be limiting.

An illumination system 101 of the EUV projection exposure system 100 comprises, in addition to a radiation source 102, an illumination optics 103 for illuminating an object field 104 in an object plane 105. 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, in particular in a scanning direction, via a reticle displacement drive 108.

In 1 For illustration purposes, a Cartesian xyz coordinate system is shown. The x-direction runs perpendicular to the plane of the drawing. The y-direction runs horizontally, and the z-direction runs vertically. The scanning direction is 1 along the y-direction. The z-direction runs perpendicular to the object plane 105.

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

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

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. The radiation source 102 can be a plasma source, for example, an LPP source (“Laser Produced Plasma”) or a DPP source (“Gas Discharged Produced Plasma”). 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 focused 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 be exposed to the illumination radiation 115 at grazing incidence (GI), i.e., at angles of incidence greater than 45°, or at normal incidence (NI), i.e., at angles of incidence less than 45°. 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 comprises a deflecting mirror 118 and, downstream of this in the beam path, a first facet mirror 119. The deflecting mirror 118 can be a flat deflecting mirror or, alternatively, a mirror with a beam-influencing effect beyond the pure deflection effect. Alternatively or additionally, the deflecting mirror 118 can be designed as a spectral filter that 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 that is optically conjugated to the object plane 105 as the field plane, it is also referred to as a field facet mirror. The first facet mirror 119 comprises a plurality of individual first facets 120, which are also referred to below as field facets. Of these facets 120, 1 only a few examples are shown.

The first facets 120 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or partially circular edge contour. The first facets 120 can be designed as flat facets or, alternatively, as convexly or concavely curved facets.

As for example from the DE 10 2008 009 600 A1 As is known, the first facets 120 themselves can also be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 119 can in particular be designed as a microelectromechanical system (MEMS system). For details, please refer to DE 10 2008 009 600 A1 referred to.

Between the collector 116 and the deflecting mirror 118, the illumination radiation 115 runs horizontally, i.e. along the y-direction.

In the beam path of the illumination optics 103, a second facet mirror 121 is arranged downstream of the first facet mirror 119. If the second facet mirror 121 is arranged in a pupil plane of the illumination optics 103, it 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 , the EP 1 614 008 B1 and the US$6,573,978 .

The second facet mirror 121 comprises 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 may also be macroscopic facets, which may, for example, be round, rectangular or hexagonal, or alternatively facets composed of micromirrors. In this regard, reference is also made to the DE 10 2008 009 600 A1 referred to.

The second facets 122 may have planar or alternatively convex or concave curved reflection surfaces.

The illumination optics 103 thus forms a double-faceted system. This basic principle is also referred to as a fly's-eye integrator.

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

With the help of the second facet mirror 121, the individual first facets 120 are imaged into the object field 104. 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 before the object field 104.

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

The illumination optics 103 has in the version shown in the 1 As shown, after the collector 116 there are exactly three mirrors, 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 after 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 a transmission optics into the object plane 105 is usually only an approximate imaging.

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

In the 1 In the example shown, the projection optics 109 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve, or a different number of mirrors M1 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 have an image-side numerical aperture that is greater than 0.5 and can also be greater than 0.6, for example, 0.7 or 0.75.

Reflection surfaces of the mirrors Mi can be designed as freeform surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one rotational symmetry axis of the reflection surface shape. The mirrors Mi, like the mirrors of the illumination optics 103, 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 be approximately as large as a z-distance between the object plane 105 and the image plane 111.

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

Each of the pupil facets 122 is assigned to exactly one of the field facets 120 to form a respective illumination channel for illuminating the object field 104. This can, in particular, result in illumination according to the Köhler principle. The far field is divided into a plurality of object fields 104 using the field facets 120. The field facets 120 generate a plurality of images of the intermediate focus on the pupil facets 122 assigned to them.

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

By arranging the pupil facets, the illumination of the entrance pupil of the projection optics 109 can be geometrically defined. By selecting the illumination channels, in particular the subset of the pupil facets that guide light, the intensity distribution in the entrance pupil of the projection optics 109 can be adjusted. This intensity distribution is also referred to as the 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 of 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 usually be precisely illuminated 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 at a single point. However, a surface can be found in which the pairwise determined spacing of the aperture rays is minimized. This surface represents the entrance pupil or a surface conjugate to it in spatial space. In particular, this surface exhibits a finite curvature.

It is possible that the projection optics 109 have different entrance pupil positions for the tangential and sagittal beam paths. 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 1 In the arrangement of the components of the illumination optics 103 shown, the pupil facet mirror 121 is arranged in a surface conjugated to the entrance pupil of the projection optics 109 net. The first field facet mirror 119 is arranged tilted relative to the object plane 105. The first facet mirror 119 is arranged tilted relative to an arrangement plane defined by the deflection mirror 118.

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

In 2 An exemplary DUV projection exposure system 200 is shown. 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, by means of which the subsequent 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 a projection optics system 206, with a plurality of optical elements, in particular lenses 207, which are held via mounts 208 in an objective housing 209 of the projection optics system 206.

Alternatively or in addition to the lenses 207 shown, various refractive, diffractive and/or reflective optical elements, including mirrors, prisms, end plates and the like, may 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 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 such that the projection beam 210 has the desired properties regarding diameter, polarization, wavefront shape, and the like when it strikes the reticle 203.

An image of the reticle 203 is generated by the projection beam 210 and transferred 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 regions of the reticle 203 are imaged onto corresponding regions 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 with a refractive index greater than 1.0. The liquid medium can be, for example, ultrapure water. Such a setup is also referred to as immersion lithography and features increased photolithographic resolution.

The use of the invention is not limited to use in projection exposure systems 100, 200, in particular not with the described structure. The invention is suitable for any lithography systems or microlithography systems, but in particular for projection exposure systems with the described structure. The invention is also suitable for EUV projection exposure systems which have a smaller image-side numerical aperture than that used in connection with 1 described, and do not have an obscured mirror M5 and/or M6. In particular, the invention is also suitable for EUV projection exposure systems that have an image-side numerical aperture of 0.25 to 0.5, preferably 0.3 to 0.4, particularly preferably 0.33. Furthermore, the invention and the following embodiments are not to be understood as being limited to a specific design.

The following figures represent the invention merely by way of example and in a highly schematic manner.

The 3 shows a schematic view of an embodiment of the device 1 according to the invention for holding an optical element 2, which in the 3 not shown. The device 1 has a holding point 5 for connection to the optical element 2, wherein the holding point 5 is connected to a carrier 3. Within the scope of the invention, it is provided that the carrier 3 has at least two rod legs 3a and a connecting piece 15, which is arranged between the holding point 5 and an upper end 9a of the rod legs 3a facing the holding point 5. The rod legs 3a converge towards each other at an acute angle 6 in the direction of the holding point 5, wherein a virtual intersection point 7 in the extension of the rod legs 3a lies beyond the holding point 5.

In the exemplary embodiments, the support 3 or the rod legs 3a of the device 1 are preferably connected to the holding point 5, as will be described in more detail below. The connection can be formed in particular by the connecting piece 15 of the rod legs 3a and, if necessary, further elements located therebetween.

At the level of the support point 5, which, when used as intended, at least partially supports the optical element 2, a distance remains between the virtual extensions (dashed lines) of the rod legs 3a. This means that the rod legs 3a or the virtual extensions of the rod legs 3a do not intersect at the support point 5 or do not have a common intersection point at the support point 5. The rod legs 3a also do not have a common intersection point at the level of the connecting piece 15.

It has proven advantageous to provide a head joint device 16, which is arranged between the connecting piece 15 and the holding point 5. This at least partially establishes the connection between the support 3 and the holding point 5. Furthermore, the head joint device 16 preferably enables tilting mobility of the device 1 relative to the holding point 5.

The support 3 can have a support foot 11, wherein the support foot 11 is arranged at a lower end 9b of the rod legs 3a facing away from the holding point 5 and connects the rod legs 3a to one another.

The carrier 3 can be moved by an actuator 4 for targeted positioning and/or alignment of the optical element 2, preferably at least along a longitudinal axis 14 of the device 1. The rod legs 3a of the carrier 3 can be moved jointly by the actuator 4, in particular simultaneously in at least approximately the same direction. In addition to the mounting, this also advantageously enables deformation-reduced positioning and/or alignment of the optical element 2 by the device 1.

The actuator 4 can be operatively connected to the support base 11. However, the actuator 4 can also be formed integrally with the support base 11.

The carrier 3 can have a compensating element 8a, 8b, which is arranged and configured such that the position of the rod legs 3a relative to one another can be adjusted. This allows deformations of the optical element 2, which can be caused, for example, by thermal expansion differences between the components and/or by movement of the rod legs 3a, to be reduced by the interaction of the rod legs 3a, the compensating element 8a, 8b, and the connecting piece 15, by counteracting tilting of the support point 5 relative to the optical element 2.

The kinematics comprising the rod legs 3a, the connecting piece 15, and the compensating element 8a, 8b, or the rod kinematics, can preferably act perpendicular to a longitudinal axis 14 of the device 1 or the rod kinematics, in particular by the rod kinematics being movable perpendicular to the longitudinal axis 14 or pivotable around the virtual intersection point 7. The head joint device 16 can also contribute to this, or this can be made possible at least partially by the tilting mobility of the head joint device 16.

Preferably, the rod kinematics can execute a compensating movement or counter-tilting to a parasitic torque around the instantaneous center of rotation or virtual intersection point 7. This allows a parasitic torque, which may be unintentionally caused, for example, by a transverse force exerted perpendicular to the longitudinal axis 14 on the support point 5 for an intended transverse displacement, to be at least partially compensated. Otherwise, the parasitic torque would be absorbed by the optical element 2, causing the support point 5 to tilt, and possibly leading to an unintentional deformation of the optical element 2.

In particular, the compensating element 8a, 8b of the rod kinematics, optionally supported by the connecting piece 15 and/or the head joint device 16, can tilt within the scope of the invention instead of the holding point 5. The relative position of the rod legs 3a depends on the tilting of the compensating element 8a, 8b, so that the relative position of the rod legs 3a shifts during the compensating movement. For further illustration, reference is also made to the 4 referred to.

The 3 also schematically indicates the z-positions of the head joint device 16 (z _B ), the rod legs 3a (z _S ) and the virtual intersection point 7 of the rod legs 3a or the instantaneous center of rotation of the rod kinematics (z _P ), as well as the angle of the rod legs 3a to the longitudinal axis 14 of the device 1 or the rod kinematics (β _S ) which should satisfy equation (1) together with other variables, including various stiffness values, as well as possible. The freely chosen origin of the coordinate system lies in the 3 so that it coincides with stop point 5.

The compensating element is preferably designed as an upper joint device 8a, which is arranged at the upper end 9a of the rod legs 3a. The upper joint device 8a connects the rod legs 3a in an articulated manner to the connecting piece 15, wherein the upper joint device 8a, together with the connecting piece 15, forms an effective connection between the rod legs 3a. Alternatively or additionally, the compensating element can also be designed as a lower joint device 8b, which is arranged at the lower end 9b of the rod legs 3a. The lower joint device 8b can connect the rod legs 3a in an articulated manner to the support base 11 of the device 1 and/or to the actuator 4.

The rod legs 3a can preferably be rigid, particularly in the axial direction. However, the rod legs 3a can also be flexible, particularly in the radial or transverse direction.

The 3 The embodiment of the device 1 shown has two rod legs 3a. The device 1 can preferably also have three or four rod legs 3a, wherein the rod legs 3a are conical to each other, in particular with acute angles 6 analogous to the 3 , are arranged.

The head joint device 16 is preferably arranged directly at the holding point 5.

The upper joint device 8a and/or the lower joint device 8b can have a plurality of joints. The head joint device 16 can also have a plurality of joints.

The joint or joints of the upper joint device 8a, the lower joint device 8b and/or the head joint device 16 can be wire joints or leaf spring joints, but also other types of joints.

The cross-section of the rod legs 3a may preferably be square, but may also be round or have another shape, in particular rectangular.

Preferably, the acute angle 6 between the rod legs 3a is less than 30°, preferably less than 15°, more preferably less than 5°, particularly preferably less than 2°. The angle 6 is in the 3 shown larger for clarity.

It is also preferred if the virtual intersection point 7 in the extension of the rod legs 3a is at least half as far, preferably at least twice as far, particularly preferably at least four times as far, beyond the holding point 5 as the rod legs 3a are long. 3 The distance between the virtual intersection point 7 and the stopping point 5 is shown smaller for clarity and to match the larger angle 6.

In the 4 is another principled view of the 3 shown embodiment of the device 1 according to the invention for holding an optical element 2. To clarify the functional principle, the device 1 is, in addition to the already shown in 3 shown positioning in the basic position (solid lines), even after a transverse displacement or deflection of the holding point 5 perpendicular to a longitudinal axis 14 of the device 1 (dashed lines).

In particular, the 4 that the holding point 5 does not tilt relative to the optical element 2 or in comparison to the basic position, since an unwanted or parasitic torque acting simultaneously with the transverse force is compensated by the joints of the upper joint device 8a, the lower joint device 8b and the head joint device 16, as well as the connecting piece 15 and the rod legs 3a, whose position relative to one another is changed after the deflection. As a result, deformations of the optical element 2, which is fixed at the holding point 5, can be reduced or prevented. This effect is primarily achieved by the position of the virtual intersection point 7 beyond the holding point 5 or the corresponding arrangement of at least two rod legs 3a coupled by the connecting piece 15 at an acute angle 6 to one another.

The 5 shows a schematic view of an embodiment of the holding device 10 according to the invention for holding an optical element 2. The holding device 10 has a first device 1a and a second device 1b, each with the features of a device 1 according to the invention. The first device 1a and the second device 1b move towards each other in the direction of a common stopping point 5 on the optical element 2.

It should be noted that the first device 1a and the second device 1b each correspond to a device 1 and are in principle interchangeable, since the designations "first" and "second" are used primarily for reasons of differentiation. In particular, the first device 1a and the second device 1b can be devices 1 according to the 3 and 4 represent.

The first device 1a and the second device 1b of the holding device 10 according to 5 Preferably, they form at least approximately a right angle to each other. However, they can also form a different angle to each other.

The acute angle 6 between the rod legs 3a of the first device 1a and the second device 1b can be spatially oriented in any desired manner relative to the optical element 2 and relative to the angle between the first device 1a and the second device 1b, depending on the desired direction of action of the device 1, 1a, 1b or the holding device 10.

An actuator 4 of the first device 1a can be arranged and designed to displace a first support foot 11a of the first device 1a for targeted positioning and/or alignment of the optical element 2. Alternatively or additionally, an actuator 4 of the second device 1b can be arranged and designed to displace a second support foot 11b of the second device 1b for targeted positioning and/or alignment of the optical element 2. The respective displacement by the actuator 4 of the first device 1a and/or the second device 1b can preferably take place at least along a longitudinal axis 14 of the first device 1a or the second device 1b, in particular on the plane defined by the longitudinal axes 14 of the first device 1a and the second device 1b.

In particular, in the 5 Also indicated by arrows is that the actuator 4 of the first device 1a can be arranged and configured to displace the first support foot 11a along the longitudinal axis 14 of the first device 1a and/or in the direction of the second support foot 11b. Alternatively or additionally, it can also be provided that the actuator 4 of the second device 1b is arranged and configured to displace the second support foot 11b along the longitudinal axis 14 of the second device 1b and/or in the direction of the first support foot 11a.

The 6 shows a schematic view of an embodiment of the arrangement 12 according to the invention and of the system 13 according to the invention for holding an optical element 2. The arrangement 12 has at least six devices 1 according to the invention, wherein preferably two devices 1 each can form a holding device 10 according to the invention, or has three holding devices 10 according to the invention. In particular, each of the holding devices 10 has two devices 1. Instead of the paired arrangement of devices 1 in the form of holding devices 10, the devices 1 could also be arranged individually.

Preferably, exactly six devices 1 are provided for the arrangement 12 according to the invention or the system 13 according to the invention. The devices 1 can be used individually or in pairs, each forming a holding device 10 for holding the optical element 2. Preferably, three holding devices 10 are provided.

The holding devices 10 are preferably designed as bipods. The two legs of a bipod can each be formed by a device 1 according to the invention, each of which has at least two rod legs 3a.

Preferably, the devices 1 and/or the holding devices 10 are arranged at least approximately uniformly distributed on an outer edge region of the optical element 2.

The V-shaped holding devices 10 can preferably be arranged tangentially to the edge of the optical element 2. The holding devices 10 are preferably oriented perpendicular to the optical element 2 or an optical surface 2a of the optical element 2. However, the holding devices 10 can also be arranged and/or oriented differently.

In a preferred embodiment of the invention, the holding devices 10 are also provided to position and/or align the optical element 2.

If the illustrated embodiment of the arrangement 12 of devices 1 or holding devices 10 is considered together with the optical element 2, a system 13 according to the invention is obtained. The system 13 thus comprises the optical element 2, at least six devices 1 according to the invention, wherein two devices 1 can each form a holding device 10 according to the invention, or comprises three holding devices 10 according to the invention for holding the optical element 2. The optical element 2 can, in particular, be a mirror or a lens.

The 7 to 9 each show a schematic view of a further embodiment of the holding device 10 according to the invention for holding an optical element 2. In contrast to the embodiment according to 5 The fixtures 1 and 1a, 1b each have four rod legs 3a with a square cross-section. This optimally utilizes the cross-section of the respective fixture 1 and 1a, 1b and achieves high rigidity in the rod direction.

The compensating element is preferably designed as an upper joint device 8a and/or as a lower joint device 8b analogous to the above description. The upper joint device 8a and/or the lower joint device 8b can in particular have a plurality of joints. The joints of the upper joint device 8a and/or the lower joint device 8b can be arranged in different planes, viewed in the axial direction of the rod legs 3a or along the longitudinal axis 14 of the device 1. The joints can in particular be arranged and designed such that the joint or joints arranged in a first plane enable deflection in a first direction and the joint or joints arranged in a second plane enable deflection in a second direction orthogonal thereto, wherein the two directions extend in one surface and the surface or plane preferably extends orthogonally to the longitudinal axis 14 of the device 1. Analogously, the head joint device 16 can also be formed by a plurality of joints, which can be arranged in different planes and are preferably deflectable in mutually orthogonal directions.

The 8 and 9 In particular, various arrangements of joints, which are preferably designed as leaf spring joints, for forming the compensating element or the upper joint device 8a and/or the lower joint device 8b are shown. In both exemplary embodiments, a head joint device 16 is fixed between the holding point 5 and the connecting piece 15, which can be formed by two joints oriented in different planes and rotated by 90° to each other.

First joints 8c of the upper joint device 8a are fixed to the connecting piece 15, which are each connected to an intermediate element 8d of the upper joint device 8a. In particular, the embodiment according to the 8 four first joints 8c and four intermediate elements 8d. The embodiment according to the 9 has two first joints 8c and two intermediate elements 8d.

Second joints 8e of the upper joint device 8a can be fixed to the intermediate elements 8d, which are each connected to the upper end 9a of one of the rod legs 3a. The embodiments according to the 8 and 9 have in particular four second joints 8e for the four rod legs 3a.

Alternatively, the first joints 8c can each be connected to the upper end 9a of one of the rod legs 3a, whereby no intermediate elements 8d and no second joints 8e are provided.

It may be advantageous if, viewed in the axial direction of the rod legs 3a, at least two adjacent joints of the upper joint device 8a and/or the lower joint device 8b are oriented rotated by 90° relative to each other, wherein the joints are in particular the first joints 8c and the second joints 8e. 8 and 9 This is shown as an example, with the first joints 8c being rotated by 90° relative to the second joints 8e.

The lower joint device 8b can be constructed analogously to the upper joint device 8a. In the embodiment according to the 8 In particular, four first joints, four intermediate elements and four second joints are provided for the lower joint device 8b, starting in the order from the support foot 11 or the actuator 4. In the embodiment according to the 9 Analogously, two first joints, two intermediate elements and four second joints are provided for the lower joint device 8b. the first joints are each fixed to the support foot 11 or the actuator 4 and the second joints are each connected to the lower end 9b of one of the rod legs 3a.

The actuators 4 in the embodiments according to the 7 to 9 can preferably be arranged and designed such that the associated support foot 11a or 11b is displaceable in the axial direction of the associated rod legs 3a or the longitudinal axis 14, which corresponds to the axial direction, and/or in the direction of the support foot 11a or 11b of the respective other device 1a, 1b.

The examples of implementation according to the 7 to 9 are also to be understood as the disclosure of only one device 1 according to the invention.

Not shown in the exemplary embodiment, but fundamentally possible, is that three devices 1 according to the invention are combined to form a common device, which converge at a common support point 5, with the rod legs 3a of the devices 1 also converging. Preferably, two such devices are then provided to hold an optical element 2.

The 10 shows a schematic view of a further embodiment of the holding device 10 according to the invention for holding an optical element 2. The basic arrangement of the components is similar to that according to the 5 , 7 , 8 and 9 . In the embodiment according to 10 The devices 1, 1a, 1b each have two rod legs 3a with a square cross-section. The respective joints of the head joint device 16, the upper joint device 8a, and/or the lower joint device 8b are preferably formed by leaf spring joints. The respective supports 3, in particular the head joint device 16, the connecting piece 15, the upper joint device 8a, the rod legs 3a, the lower joint device 8b, and/or the support base 11, 11a, 11b, can be at least partially monolithic.

In this embodiment, the devices 1, 1a, 1b or the rod kinematics act in particular in the radial direction of the optical element 2, when the holding device 10 is analogous to the 6 is arranged tangentially on the outer edge region or edge of the optical element 2. The embodiment of the 10 is preferably combined with the fact that the actuator 4 is arranged and designed such that the support foot 11a and/or 11b of the device 1a and/or 1b is displaceable in the direction of the respective other support foot 11b or 11a.

The 3 to 10 also serve to disclose a method according to the invention for holding and in particular for positioning and/or aligning an optical element 2, wherein the optical element 2 is held and in particular positioned and/or aligned with at least one device 1 according to the invention and/or a holding device 10 according to the invention or an arrangement 12 according to the invention.

The examples of implementation according to the 3 to 10 The device 1 according to the invention or the holding device 10 according to the invention or the arrangement 12 according to the invention or the system 13 according to the invention or the method according to the invention are particularly suitable for holding, and optionally for positioning and/or aligning, an optical element 2 of a lithography system. The optical element 2 can be, in particular, an optical element 116, 118, 119, 120, 121, 122, 111, 1207 of a projection exposure system 100, 200 for semiconductor lithography, with an illumination system 101, 201 with a radiation source 102 and an optics 103, 109, 206, according to the 1 and 2 According to the invention, at least one of the optical elements 116, 118, 119, 120, 121, 122, Mi, 207 is held, and optionally positioned and/or aligned, by at least one device 1 according to the invention and/or a holding device 10 according to the invention or an arrangement 12 according to the invention.

List of reference symbols

1

device

1a

First device

1b

Second device

2

Optical element

2a

Optical surface

3

carrier

3a

Rod leg

4

Actuator

5

stopping point

6

Acute angle

7

Virtual intersection

8a

Compensating element, upper joint device

8b

Compensating element, lower joint device

8c

First joint

8d

Intermediate element

8e

Second joint

9a

Upper end (of rod leg 3)

9b

Lower end (of rod leg 3)

10

Holding device

11

Support foot (of device 1)

11a

First support foot (of the first device 1a)

11b

Second support foot (of the second device 1b)

12

arrangement

13

system

14

Longitudinal axis (of device 1)

15

connecting piece

16

Head joint device

100

EUV projection exposure system

101

lighting system

102

Radiation source

103

Lighting optics

104

Object field

105

Object level

106

Reticle

107

Reticle holder

108

Reticle displacement drive

109

Projection optics

110

Image field

111

Image plane

112

wafers

113

Wafer holder

114

Wafer relocation drive

115

EUV / useful / illumination radiation

116

collector

117

Intermediate focal plane

118

Deflecting mirror

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 stages

203

Reticle

204

wafers

205

Wafer holder

206

Projection optics

207

lens

208

Version

209

lens housing

210

Projection beam

Wed

Mirror

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

• EP 1 028 342 A1 [0012]
• WO 2006/000352 A1 [0013]
• US 5 986 827 A [0014, 0015]
• DE 10 2018 200 181 A1 [0017, 0018]
• DE 10 2018 200 178 A1 [0132]
• DE 10 2008 009 600 A1 [0174, 0178]
• US 2006/0132747 A1 [0176]
• EP 1 614 008 B1 [0176]
• US 6,573,978 [0176]
• US 2018/0074303 A1 [0191]

Claims (28)

Device (1) for holding an optical element (2), in particular an optical element of a lithography system, with a holding point (5) for connection to the optical element (2), wherein the holding point (5) is connected to a carrier (3), characterized in that the carrier (3) has at least two rod legs (3a) and a connecting piece (15), wherein the connecting piece (15) is arranged between the holding point (5) and an upper end (9a) of the rod legs (3a) facing the holding point (5) and connects the rod legs (3a) to one another, wherein the rod legs (3a) converge towards one another at an acute angle (6) in the direction of the holding point (5), and wherein a virtual intersection point (7) in the extension of the rod legs (3a) lies beyond the holding point (5). Device (1) according to Claim 1 , characterized in that a head joint device (16) is provided, wherein the head joint device (16) is arranged between the connecting piece (15) and the holding point (5). Device (1) according to Claim 1 or 2 , characterized in that the support (3) has a support foot (11), wherein the support foot (11) is arranged at a lower end (9b) of the rod legs (3a) facing away from the holding point (5) and connects the rod legs (3a) to one another. Device (1) according to Claim 1 , 2 or 3 , characterized in that the carrier (3) can be moved by an actuator (4) for a targeted positioning and/or alignment of the optical element (2), wherein the rod legs (3a) of the carrier (3) can be moved jointly by the actuator (4), preferably at least along a longitudinal axis (14) of the device (1). Device (1) according to Claim 4 , characterized in that the actuator (4) is operatively connected to the support foot (11) and/or is formed integrally with the support foot (11). Device (1) according to one of the Claims 1 until 5 , characterized in that the carrier (3) has a compensating element (8a, 8b), wherein the compensating element (8a, 8b) is arranged and designed such that the position of the rod legs (3a) relative to one another can be changed in order to reduce deformations of the optical element (2) by means of cooperation of the rod legs (3a), the compensating element (8a, 8b) and the connecting piece (15) in order to counteract tilting of the holding point (5) relative to the optical element (2). Device (1) according to Claim 6 , characterized in that the compensating element is designed as an upper joint device (8a) which is arranged at the upper end (9a) of the rod legs (3a) and connects the rod legs (3a) in an articulated manner to the connecting piece (15), and/or the compensating element is designed as a lower joint device (8b) which is arranged at the lower end (9b) of the rod legs (3a) and connects the rod legs (3a) in an articulated manner to the support foot (11) of the device (1) and/or the actuator (4). Device according to one of the Claims 1 until 7 , characterized in that the rod legs (3a) are rigid, in particular in the axial direction. Device according to one of the Claims 1 until 7 , characterized in that the rod legs (3a) are flexible, in particular in the radial direction. Device (1) according to one of the Claims 1 until 9 , characterized in that the device has two, three or four rod legs (3a), wherein the rod legs (3a) are arranged conically. Device (1) according to one of the Claims 2 until 10 , characterized in that the head joint device (16) is arranged directly at the holding point (5). Device (1) according to one of the Claims 7 until 11 , characterized in that the upper joint device (8a) and/or the lower joint device (8b) has a plurality of joints. Device (1) according to one of the Claims 7 until 12 , characterized in that first joints (8c) of the upper joint device (8a) are fixed to the connecting piece (15), which are each connected to the upper end (9a) of one of the rod legs (3a) or to an intermediate element (8d) of the upper joint device (8a). Device according to Claim 13 , characterized in that second joints (8e) of the upper joint device (8a) are fixed to the intermediate elements (8d), which are each connected to the upper end (9a) of one of the rod legs (3a). Device (1) according to one of the Claims 12 until 14 , characterized in that , viewed in the axial direction of the rod legs (3a), at least two adjacent joints of the upper joint device (8a) are oriented rotated by 90° to one another, the joints being in particular the first joints (8c) and the second joints (8e). Device (1) according to one of the Claims 1 until 15 , characterized in that the cross-section of the rod legs (3a) is square or rectangular. Device (1) according to one of the Claims 1 until 16 , characterized in that the acute angle (6) between the rod legs (3a) is less than 30°, preferably less than 15°, more preferably less than 5°, particularly preferably less than 2°. Device (1) according to one of the Claims 1 until 17 , characterized in that the virtual intersection point (7) in the extension of the rod legs (3a) lies at least half as far, preferably at least twice as far, particularly preferably at least four times as far, beyond the holding point (5) as the rod legs (3a) are long. Holding device (10) for holding an optical element (2), in particular an optical element of a lithography system, at least comprising a first device (1a) and a second device (1b), each according to one of the Claims 1 until 18 , characterized in that the first device (1a) and the second device (1b) converge towards each other in the direction of a common holding point (5) on the optical element (2). Holding device (10) according to Claim 19 , characterized in that the first device (1a) and the second device (1b) form at least approximately a right angle to one another. Holding device (10) according to Claim 19 or 20 , characterized in that an actuator (4) of the first device (1a) for a targeted positioning and/or alignment of the optical element (2) is arranged and designed in such a way to displace a first support foot (11a) of the first device (1a), and/or an actuator (4) of the second device (1b) for a targeted positioning and/or alignment of the optical element (2) is arranged and designed in such a way to displace a second support foot (11b) of the second device (1b), in each case preferably at least along a longitudinal axis (14) of the first device (1a) or of the second device (1b), in particular on the plane defined by the longitudinal axes (14) of the first device (1a) and the second device (1b). Holding device (10) according to Claim 21 , characterized in that the actuator (4) of the first device (1a) is arranged and designed such that it moves the first support foot (11a) along the longitudinal axis (14) of the first device (1a) and/or in the direction of the second support foot (11b), and/or the actuator (4) of the second device (1b) is arranged and designed such that it moves the second support foot (11b) along the longitudinal axis (14) of the second device (1b) and/or in the direction of the first support foot (11a). Arrangement (12) for holding an optical element (2), in particular an optical element of a lithography system, comprising at least six devices (1) according to one of the Claims 1 until 18 or three holding devices (10) according to one of the Claims 19 until 22 . Arrangement (12) according to Claim 23 , characterized in that the devices (1) and/or the holding devices (10) are arranged at least approximately uniformly distributed on an outer edge region of the optical element (2). System (13) comprising an optical element (2), in particular an optical element of a lithography system, and at least six devices (1) according to one of the Claims 1 until 18 or three holding devices (10) according to one of the Claims 19 until 22 for holding the optical element (2). System (13) according to Claim 25 , characterized in that the optical element (2) is a mirror or a lens. Method for holding and in particular for positioning and/or aligning an optical element (2), in particular an optical element of a lithography system, characterized in that the optical element (2) is provided with at least one device (1) according to one of the Claims 1 until 18 and/or a holding device (10) according to one of the Claims 19 until 22 or an order (12) according to Claim 23 or 24 held and in particular positioned and/or aligned. Lithography system, in particular a projection exposure system (100, 200) for semiconductor lithography, with an illumination system (101, 201) with a radiation source (102) and an optics (103, 109, 206) which has at least one optical element (116, 118, 119, 120, 121, 122, Mi, 207), characterized in that the optical element (116, 118, 119, 120, 121, 122, Mi, 207) is illuminated by at least one device (1) according to one of the Claims 1 until 18 and/or a holding device (10) according to one of the Claims 19 until 22 or an order (12) according to Claim 23 or 24 is held.