DEVICE AND METHOD FOR OPTICAL PROCESSING OF AN OBJECT

Description

Field of the invention

[0001] The present invention lies in the field of optical 3D lithography and relates to a device and a method for optically processing an object. The device and method, in particular, enable the handling of immersion media and / or photoresists in three-dimensional direct-writing laser lithography of samples.

[0002] In direct-writing laser lithography processes, a focused laser beam can be moved through the volume of a liquid or solid photosensitive material, known as a "photoresist," to define a structure that can be exposed in a subsequent development step. To achieve high precision and resolution, the light used for patterning should be irradiated into the photoresist through an outer interface in such a way that no, or at most minimal, disturbances to the beam profile of the incident light occur. This generally requires a well-defined interface with optical quality in terms of smoothness and flatness, especially when high-resolution, three-dimensional structures are created using multiphoton polymerization.Focusing optics, preferably lens-based objectives with the highest possible numerical aperture (NA), are preferably used for exposure to achieve a very small focal volume. In combination with a pulsed laser beam, very high optical intensities can be achieved briefly in this focal volume, which can lead to multiphoton absorption in a limited spatial area and thus to the initiation of a polymerization reaction. To increase the NA and thus the achievable peak intensities, so-called immersion lithography processes are often used. In these processes, the light used for structuring is irradiated and focused into a single immersion medium or into an arrangement of multiple immersion media, each with a refractive index of n greater than 1.The high NA lenses used here usually have a short working distance, typically at most 10 mm, preferably at most 1 mm, particularly preferably at most 500 µm or less.

[0003] Analogous to high-resolution lithography, the high-resolution optical characterization of objects is also largely based on the fact that the light used for characterization can be coupled through a well-defined interface into a highly refractive immersion medium surrounding the structure to be imaged, without or with as little disturbance as possible. State of the art

[0004] J. Serbin et al., Fabrication of woodpile structures by two-photon polymerization and investigation of their optical properties, Optics Express 12 (21), pp. 5221-5228, 2004, describes the handling of immersion fluids and photoresists in 3D direct-writing laser lithography using a thin cover glass. The photoresist is first applied to a substrate surrounding the object and covered with the cover glass, which is immobile with respect to the substrate and in direct contact with the photoresist. The high NA objective used for lithography and / or imaging is then brought close to the top of the cover glass, and the gap between the cover glass and the objective is filled with refractive index-matched immersion oil. The disadvantage of this is that it does not allow for the writing of structures of any height, since the working distance of the objective and the thickness of the cover glass dictate the maximum height of the structures.For objectives with a high NA, the working distance is relatively short, often on the order of a few hundred micrometers. At the same time, the cover glasses used have a thickness of 100–200 µm to achieve sufficient rigidity for a well-defined interface of high optical quality. This limits possible structure heights to a few hundred micrometers. Furthermore, the fixed distances between the object and the cover glass can lead to geometric aberrations if writing is not uniform at a specific depth, for which the objective and the immersion fluid or photoresist used are designed.

[0005] K. Obata et al., High-aspect 3D two-photon polymerization structuring with widened objective working range (WOW-2PP), Light: Science & Applications 2, page e116, 2013, describes an arrangement in which the coverslip is attached directly to the objective, rather than to the specimen. This allows the objective and coverslip to be moved freely relative to the specimen. The distance between the objective and coverslip can be adjusted so that the focus of the light beam lies in the volume of the photoresist directly below the coverslip. Furthermore, an immersion oil with a refractive index matched to the refractive index can be placed between the coverslip and the objective. This allows structures of any height to be written. The disadvantage of this, however, is that when the objective is positioned, the coverslip attached to the objective moves relative to the specimen.This can generate forces in the photoresist that lead to opposing forces acting on the objective and / or the substrate and / or to a relative movement between the substrate and layers of the immersion medium adjacent to the substrate. This can make precise positioning of the substrate and objective difficult and, by introducing shear forces into the photoresist, can also lead to damage to structures already present on the substrate, particularly if these structures are particularly small and / or have high aspect ratios. Furthermore, automatically changing the objective during operation of the device is difficult: Since the cover glass is attached directly to the objective, changing the objective inevitably results in a disruption of physical contact between the cover glass and the photoresist adjacent to the object side.This can also generate forces in the photoresist that can damage previously fabricated optical structures or cause problems when re-establishing optical contact between the photoresist and a newly inserted lens. A further disadvantage is that this procedure is not suitable for the lithographic structuring of objects with a high surface topography: The distance between the lens and the cover glass is set such that the focal point of the light beam lies directly below the cover glass in the volume of the photoresist. For objects with a high surface topography, this can lead to a collision between the cover glass attached to the lens and parts of the object during the writing process, thus destroying parts of the object.Furthermore, the photoresist can bleed if the lens and its cover glass are moved too far away from the specimen. Another disadvantage is that changing the cover glass attached to the lens can exert forces on the lens, potentially causing misalignment of the optical system. Changing the cover glass may be necessary, for example, to avoid cross-contamination when consecutively exposing substrates.

[0006] US 2016 / 0299426 A1 describes a device that additionally comprises a transparent element attached to the lens and configured to protect the lens from contamination. This device is subject to essentially the same limitations as the approach described by K. Obata et al., supra. Furthermore, the volume of photoresist used cannot be adapted to the structure to be written, since the transparent element is fixedly attached to the lens and must always fill the entire space between the axially movable lens and the object. Furthermore, a precise adaptation of the refractive index of the photoresist to the lens used is required, since no further degrees of freedom are provided to compensate for monochromatic aberrations.This severely limits the range of usable photoresists and leads to disadvantages in the implementation of stable lithography processes in an industrial environment, for example due to temperature dependence or aging of the photoresist or due to fluctuations in the composition of the starting materials used to produce the photoresist.

[0007] WO 2011 / 141521 A1 and US 2012 / 0218535 A1 each describe a device and a method for 3D lithography using two-photon polymerization, in which the lens is immersed directly into the photoresist; a cover glass or other element located between the lens and the object is omitted. This also allows structures of any height to be created. However, moving the lens relative to the object can also exert forces on the lens or introduce them into the photoresist, which are associated with the disadvantages described above. Furthermore, with this approach, changing the lens during operation of the device inevitably leads to the physical contact between the lens and the photoresist adjacent to the object being removed.Furthermore, it is not possible to adapt the amount of photoresist to the structure to be written, as the entire space between the lens and the object must always be filled with the photoresist, which serves as a homogeneous immersion medium. Furthermore, there is a risk that the lens will become contaminated by contact with the photoresist, which serves as the immersion medium and is in direct contact with the object, or that cross-contamination of objects via photoresist residue adhering to the lens can occur. Furthermore, the lens itself is exposed to the effects of the photoresist, which, depending on the photoresist composition, can lead to long-term damage, for example, to seals or lens cements.Furthermore, unwanted polymerization of the liquid photoresist on the lens's exit window can occur, for example, as a result of short-wave light being intentionally or inadvertently irradiated into the lens, which can damage or destroy the lens. These aspects are particularly disadvantageous for an industrial process, since regular cleaning of the lens means a significant loss of time in production. A further disadvantage is that the refractive index must be precisely adapted to the lens. Furthermore, these concepts do not allow for the transfer of an object covered with photoresist to different functional units while protecting the photoresist from contamination, unwanted irradiation with short-wave light, or contact with oxygen or humidity.

[0008] US 2005 / 0158673 A1 discloses a device for 2D immersion lithography in which the immersion liquid is encapsulated in a balloon formed from a thin membrane. The balloon filled with immersion liquid is positioned between the objective and the object such that it touches both the objective and the object. This allows an immersion objective to be used for high-resolution 2D lithography and protects it from contamination. The method proposed here is further limited to solid photoresists, since liquid photoresists would be displaced from the object by the pressure of the liquid-filled balloon. With solid photoresists, the application is further limited to cases in which the photoresist has a very flat surface of optical quality.

[0009] US 7570343 B2 discloses a device and a method for projection lithography, with which 2D structures are created on essentially planar objects, which typically have maximum irregularities on the order of one or a few light wavelengths of the lithography radiation. It is proposed here to insert a closure element that is transparent to the projection light into the object-side light path of the system, whereby the closure element can also be used to separate two immersion liquids. The closure element can be either a solid plate with a macroscopic thickness or a thin membrane. The position of the closure element between the object and the objective can be adjusted by appropriate adjustment elements during system setup. Micrometer screws are proposed as adjustment elements, which are arranged in a space between an end surface of the objective and the object.Alternatively, the position of the membrane can be adjusted using the hydrostatic pressure of the adjacent immersion liquids. The closure element can also be used to correct aberrations of the lithography device through a suitable geometric shape. In the case of a flexible membrane, the geometric shape can also be achieved by varying the hydrostatic pressure of the adjacent immersion liquids on either side.

[0010] The position of the terminating element between the lens and the object is set once during setup of the lithography device, for example, manually using micrometer screws; changing this position during the writing process is not desired. Furthermore, patent US 7570343 B2 refers exclusively to the application of projection lithography on flat substrates, where no axial relative movement of the lens with respect to the object is required during the exposure process. This allows the use of large lenses with a large working distance and yet high NA, which are also heavy. Furthermore, the lithography device can be operated with a small safety distance between the terminating element and the object.The large working distance of the objective and the small safety distance make it possible to incorporate relatively large optical or mechanical assemblies into the space between the end face of the objective and the object, reducing the usable working distance of the arrangement to a fraction of the working distance of the objective. Thus, the closure elements proposed here are sometimes designed as solid plates of macroscopic thickness, which themselves fill a large part of the installation space between the end face of the objective and the object, or they have mechanical positioning elements that are also inserted between the end face of the objective and the object. As an alternative possibility for positioning a transparent closure element designed as a thin membrane, a variation of the hydrostatic pressure of the immersion liquid on at least one side of the membrane is described.However, with a flexible membrane, a change in pressure changes not only its position but also its curvature. This means that the position and refractive power of the membrane cannot be adjusted independently of each other by varying the pressure. Furthermore, adjusting the pressure requires a larger volume of immersion fluid, which, in the case of a photoresist serving as the immersion fluid, is disadvantageous in terms of minimizing the volume of photoresist. Furthermore, adjusting the position using hydrostatic pressure requires at least one hermetically sealed area, which encompasses either part of the objective, the entire objective, or the sample, which is impractical in many application situations.

[0011] WO 2004 / 077123 A2 discloses a microscopic system comprising a plurality of interchangeable objective lenses; an objective lens exchange element for holding each objective lens, the exchange element being configured to place a selected objective lens in an optical axis of the microscopic system, each objective lens being held by the exchange element such that each objective lens is movable coaxially with respect to the optical axis and with respect to the exchange system; and an actuator element for moving the selected objective lens coaxially with respect to the optical axis and with respect to the exchange system in order to focus the selected objective lens with respect to a sample.

[0012] US 2007 / 0024982 A1 discloses an imaging system of a microlithographic projection exposure device for achieving improvements in the projection of external optical surfaces against contamination. In an imaging system comprising a projection objective configured to project an image of a mask that can be placed in a position in an object plane onto a light-sensitive coating that can be placed in a position in an image plane, a membrane that is substantially transparent to an operating wavelength of the projection objective is arranged with respect to the external optical surface of the projection objective such that a gap is formed between the optical surface and the membrane, which gap is configured to receive a liquid or gaseous medium. T. Bückmann, N. Stenger, M. Kadic, J. Kaschke, A. Frölich, T. Kennerknecht, C. Eberl, M. Thiel, and M.Wegener, Tailored 3D Mechanical Metamaterials Made by Dip-in Direct-Laser-Writing Optical Lithography, Adv. Mater. 24, pp. 2710-14, 2012, describes the fabrication of three-dimensional metamaterials using direct laser writing. Object of the invention

[0013] Based on this, the object of the present invention is to provide a device and a method for optically processing an object which at least partially overcome the disadvantages and limitations of the prior art.

[0014] The device and method are intended, in particular, to enable the handling of immersion media and / or photoresists in 3D direct-writing laser lithography, which particularly meets the requirements of industrial applications in the field of high-throughput lithography processes. A common problem here is that the immersion medium used for lithography or imaging is in physical contact with the objective lens and the substrate. For this purpose, a liquid immersion medium is often used, which is applied to the substrate and simultaneously in direct contact with an exit window of the objective lens. The term "substrate" describes one or more interconnected solid bodies on which a target structure is to be created lithographically and / or an existing structure is to be optically characterized. In the following text, it is used synonymously with the term "object."An "exit window" is defined below as an optically transparent window integrated into the lens or connected to it by direct physical contact, through which light enters or is received from an immersion medium adjacent to the lens. An exit window can also be the lens cover of the lens or a glass plate, coating, or film protecting this lens cover. While the use of a continuous liquid immersion medium between the exit window and the substrate represents a simple and reliable method for achieving high optical resolutions in laboratory applications, it is less suitable for use in industrial optical characterization or 3D lithography processes and is associated with various limitations in practical handling, particularly for the following reasons.These limitations of the prior art described above concern in particular the following points: . Transfer of contamination between lens and substrate: In high-throughput characterization or 3D lithography processes, a single lens is used to process a large number of substrates within a short period of time, each of which comes into direct physical contact with the lens's immersion medium. Cleaning the lens by completely removing residues of the immersion medium adhering to the lens is not possible or practical between substrate changes. This can lead to cross-contamination, i.e., the transfer of contaminants from one substrate to one or more other substrates. Damage to the lens: In 3D direct-writing laser lithography processes, the photoresist can also serve as an immersion medium that is in direct physical contact with the lens's exit window.There is a risk of unwanted polymerization of the liquid photoresist on the lens's exit window, particularly as a result of short-wave light that is intentionally or unintentionally irradiated into the lens. This can destroy the lens. There is also a risk that the photoresist will chemically attack and destroy or age components of the lens, such as seals or cement. The same risk exists with photoresists that can only be removed from the lens using aggressive solvents, which have a damaging effect on parts of the lens. Use of lenses with a short working distance: In 3D direct-writing laser lithography, lenses with a very short working distance of just a few hundred micrometers are often used.Such a short working distance has the advantage that the lens can be designed compactly with a small diameter and low weight, even at high NA, thus enabling rapid movement of the lens during the writing process. However, lenses with a short working distance severely limit the space available between the lens and the substrate. Devices and methods for handling immersion media and / or photoresists in 3D lithography and imaging should therefore be designed to limit the usable working distance of the lens, i.e. the distance between the focal plane of the lens and the optical or mechanical component closest to the focal plane in the direction of the lens, as little as possible.Lithographic production of tall structures with lenses with a short working distance: For the lithographic production of functional components, it is often advantageous to be able to create structures whose height exceeds the working distance of the lens. Introduction of forces into the immersion medium and / or the lens: In high-throughput characterization or 3D lithography processes, the lens is often moved laterally or axially relative to the substrate. In this case, an axial relative movement usually serves to adjust the focal plane and thus, in particular, to address different depths of a 3D structure to be created or characterized. A lateral movement can be used, in particular, to create or capture structures whose lateral dimensions exceed the field of view or the writing field of the lens that can be addressed using a beam scanner.In both cases, a relative movement of the lens to the substrate can introduce forces into the immersion medium, which can lead to counterforces acting on the lens and / or the substrate and / or to a relative movement between the substrate and layers of the immersion medium adjacent to the substrate. The counterforces acting on the lens and / or the substrate can make it difficult to position the substrate and lens precisely. Furthermore, a relative movement between the substrate and the layers of the immersion medium adjacent to the substrate can damage structures on the substrate, especially when the structures are particularly small and / or have high aspect ratios and are therefore particularly susceptible to movement of the surrounding photoresist.Automatic lens change, stable optical system alignment, and rapid lens movement: To enable rapid axial and / or lateral lens movement, primarily to increase throughput, it is advantageous to keep the mass of the lens and its attached components as low as possible. This makes it possible to minimize the forces acting on the lens during device operation and / or process execution, which could potentially lead to gradual or sudden lens misalignment. Furthermore, it should be possible to change the lens as automatically as possible during operation, for example, using a lens revolver, without changing the position of the substrate or causing disturbances in the immersion medium or photoresist near the substrate.Such disturbances can be caused, for example, by a broken contact between the lens's exit window and the immersion medium or photoresist on the object side. Automated application of the immersion medium and transfer within production chains: In automated processes, it can often be advantageous to perform the application of the immersion medium, especially the immersion liquid, to the substrate on the one hand, and the lithographic processing or optical characterization of the substrate on the other, spatially separated in different functional units.It would be advantageous to transfer the substrates covered with the immersion medium between two different functional units under normal ambient conditions, if possible without impairment, in particular without the occurrence of contamination or undesired exposure, without having to observe special requirements with regard to cleanliness (e.g. clean room quality), exposure (e.g. yellow light environment) and / or atmosphere (e.g. low oxygen or low humidity environment) in a spatial area crossed during the transfer.This could make it possible during lithographic structuring, after the local application of a liquid photoresist serving as an immersion medium in a first functional unit ("dispenser"), to transfer the substrate to a second functional unit serving for structuring ("lithography unit"), without maintaining clean room conditions throughout the transfer and without ensuring that there is no exposure to daylight or other UV-containing radiation spectra. Furthermore, in many cases, it would be advantageous if contact of the photoresist with certain substances, such as oxygen or atmospheric moisture, could be at least largely avoided.Furthermore, high mechanical stability of a droplet formed by the photoresist after application to the substrate would be desirable. This droplet can tend to flow at certain surface energies between the substrate and the photoresist. Lithographic structuring using dry lenses: To avoid the disadvantages described above, it may be advisable to forgo the use of an immersion lens and instead use a so-called "dry lens" that is not in direct physical contact with the immersion medium. This is always possible if the NA required for the respective application is less than 1 and can therefore be achieved without an immersion lens.In this case, however, with liquid immersion media or photoresists, the challenge can arise of creating a well-defined interface with optical quality through which light can be coupled into and out of the immersion medium or photoresist without unforeseeable interference. However, the use of a glass plate, through which light can be irradiated from free space into a liquid medium and then out again, is often not feasible, as this further reduces the usable working range of the lens on the object side, which is often already limited by the short working distance.Creating a well-defined optical interface can also be problematic when solid immersion media or photoresists are used on substrates with high surface topographies or significant height variations, which are transferred to corresponding height variations on the photoresist surface when a solid photoresist is applied. Interference-free coupling of a light beam for high-resolution lithographic structuring in the volume of a solid photoresist with strong surface topography is not possible with an air lens. An example of an object to be lithographically processed with a strong surface topography is so-called optical "multi-chip modules", i.e. several individual chips of different thicknesses mounted on a common microscope slide, which can be combined, for example, using direct-write lithography processes to incorporate optical elements, e.g., microlenses or freeform waveguides (so-called "multi-chip modules").It would therefore be desirable to be able to use dry lenses for structuring or imaging liquid photoresist or solid photoresists with very uneven surface topography, while limiting the usable working distance of the lens as little as possible. Photoresist consumption in 3D direct-writing immersion lithography: In three-dimensional direct-writing immersion lithography, the photoresist itself is often used as the only immersion medium. This can lead to high photoresist consumption, as it usually fills the entire space between the lens and the substrate, while only a fraction of it is actually required to create a target structure.This can be particularly disadvantageous when producing small structures or with lenses with a long working distance, since the volume to be filled is particularly large in these cases. Therefore, it would be advantageous to minimize photoresist consumption and adjust the process quantity as optimally as possible, ideally also during device operation and / or the execution of the process. Adjusting the immersion medium to avoid aberrations: To achieve high resolutions, it is advantageous to adjust the refractive index of the immersion medium as precisely as possible to the refractive index of the lens in order to avoid or minimize aberrations. The term "aberrations" refers to deviations from the ideal optical image, which would lead to ideal, defect-free imaging or the smallest possible focus volume of the light beam used for optical characterization or lithographic processing.This includes both geometric or monochromatic aberrations, which arise from the geometric-optical beam paths and the refractive indices occurring along them and which already occur with monochromatic lithography or imaging light, as well as chromatic aberrations resulting from the wavelength dependence of the refractive indices of the materials present in the beam path. In direct-write lithography processes with a photoresist serving as the immersion medium, the compensation of aberrations may require precise adjustment of the refractive index of the photoresist, particularly through special, precisely adjusted mixtures of different starting materials. This is accompanied by a narrowing of usable process parameters and possible materials.It would be advantageous to be able to process different photoresists with at least small variations in refractive index and compensate for any aberrations that occur during operation. Once aberration compensation has been achieved, it should be possible to address the widest possible range of depths for imaging or lithographic patterning. Disclosure of the invention

[0015] This object is achieved by a device and a method for optically processing an object having the features of the independent patent claims. Advantageous further developments, which can be implemented individually or in any combination, are presented in the dependent claims.

[0016] In the following, the terms "have," "have," "comprise," or "include," or any grammatical variations thereof, are used non-exclusively. Accordingly, these terms can refer both to situations in which, besides the features introduced by these terms, no further features are present, or to situations in which one or more further features are present. For example, the expression "A has B," "A has B," "A comprises B," or "A includes B" can refer both to the situation in which, apart from B, no further element is present in A (i.e., a situation in which A consists exclusively of B), and to the situation in which, in addition to B, one or more further elements are present in A, for example, element C, elements C and D, or even further elements.

[0017] Furthermore, it should be noted that the terms "at least one" and "one or more," as well as grammatical variations of these terms, when used in connection with one or more elements or features and intended to express that the element or feature may be provided singly or multiple times, are generally used only once, for example, when the feature or element is first introduced. Upon subsequent re-mention of the feature or element, the corresponding term "at least one" or "one or more" is generally no longer used, without limiting the possibility that the feature or element may be provided singly or multiple times.

[0018] Furthermore, the terms "preferred," "preferably," "in particular," "for example," or similar terms are used below in connection with optional features, without limiting alternative embodiments. Thus, features introduced by these terms are optional features, and these features are not intended to limit the scope of the claims, and in particular the independent claims. Thus, as those skilled in the art will recognize, the invention can also be carried out using other embodiments. Similarly, features introduced by "in one embodiment of the invention" or "in an embodiment of the invention" are understood as optional features, without limiting alternative embodiments or the scope of the independent claims.Furthermore, these introductory expressions are intended to leave untouched all possibilities of combining the features introduced thereby with other features, whether optional or non-optional.

[0019] In a first aspect, the present invention relates to a device for optically processing an object. The term "object" or "substrate" refers to a single solid or at least two interconnected solids, wherein a target structure is to be lithographically generated on the at least one solid. The object can comprise a single solid or an arrangement of individual objects, which can be applied to a common carrier plate and, for example, form so-called "multi-chip modules." The object is applied to a slide, which can preferably be mounted on a stage supporting the slide. The term "slide" refers to an arrangement configured to receive the object.The term "object stage" is used here to describe a positioning stage designed to hold the object or slide, allowing the object and slide to be positioned as precisely as possible within the workspace of an optical characterization or processing unit described in more detail below. The slide can be designed as an object transport unit that protects the object or can be integrated into an object transport unit.

[0020] The term "optical characterization or optical processing" describes methods used for the three-dimensional (3D) spatially resolved manipulation of the material properties of an object or for the three-dimensional spatially resolved acquisition of information related to an object. In this case, the resolution relevant for the manipulation or acquisition in all three spatial directions can preferably be better than 20 µm, particularly preferably better than 5 µm, and especially better than 1 µm. The methods used here can preferably be so-called "direct-writing methods," in which the spatially resolved manipulation or acquisition of the object, in the simplest case, takes place in at least one volume area localized in all spatial directions, which can be moved through the entire area to be structured or acquired using a scanning method.The volume region can, for example, be generated in the form of at least one spatially highly localized focal point of light beams with a high numerical aperture (NA), in particular in two-photon lithography, in which highly focused laser beams are used, or in laser scanning microscopy (LSM). laser scanning microscopy,LSM (point scanner). In two-photon lithography, a femtosecond laser is preferably used to generate ultrashort pulses of laser beams. These ultrashort pulses result in a high peak intensity and thus a high probability of two-photon processes. The pulse duration is preferably at most 5 ps, particularly preferably at most 1 ps, in particular at most 250 fs. The wavelength of the laser beams is preferably from 200 nm to 2000 nm, particularly preferably from 400 nm to 1700 nm, in particular from 500 nm to 1070 nm.Further applications can involve the manipulation or capture of the object by generating a volume region that is essentially linear (1D) or planar (2D), within which a 1D or 2D spatially resolved manipulation or capture of the object is possible by optical irradiation or detection. This region is additionally moved by a suitable scanning process in one spatial direction or in two spatial directions through the three-dimensional area to be structured or captured (line or area scanner). Examples of this are the 3D spatially resolved capture of objects by taking a stack of images at different depths. z-stack ) ,preferably combined with a numerical reconstruction of the three-dimensional object. In these methods, the best possible spatial resolution in the z-direction is inextricably linked to the most precise axial movement of the lens relative to the object during the writing or recording process, as well as to a shallow depth of field, which is achieved by a high NA. These methods therefore differ in particular from methods for 2D lithography (e.g., projection lithography) and 2D imaging, which do not use spatially resolved structuring or information acquisition in the axial direction and can therefore manage without an axial movement of the lens relative to the object and do not necessarily require a shallow depth of field.

[0021] It is expressly pointed out that problems arising in direct-write lithography also apply in the same or similar way to imaging processes that utilize an immersion medium. However, these are not part of the present invention. All tasks and solutions described above and below for lithography processes are therefore transferable to analogous tasks and solutions related to optical characterization, even if this is not explicitly stated in the individual case.

[0022] The proposed device for optical processing of an object comprises at least a specimen slide for receiving an object; an optical processing unit comprising at least one device for generating or receiving light and an objective lens for illuminating the object using the light or for detecting the light from the object, wherein the objective lens has an end surface facing the specimen slide, wherein the end surface has a border, wherein the objective lens further defines an optical axis; at least one membrane inserted between the objective lens and the specimen slide, wherein the membrane has a partial region configured for the penetration of the light, wherein at least the partial region of the membrane is movable in the axial direction with respect to the optical axis, at least one membrane holder for holding the at least one membrane, and at least one immersion medium, which is inserted at least between the membrane and the specimen slide, wherein the membrane and the membrane holder are attached at a location outside the lens, and wherein the membrane is arranged on the membrane holder such that first contact points between the membrane and the membrane holder lie on or outside a lateral surface which is formed by a geometric extrusion of the edge of the end surface of the lens parallel to the optical axis, characterized in that the immersion medium which is introduced between the membrane and the slide is in the form of a liquid photoresist.

[0023] The proposed device thus comprises a membrane that is movable in the axial direction or at least a partial area of ​​the membrane that is movable in the axial direction and an immersion medium in the form of a liquid photoresist that is inserted between the lens and the object to be lithographically processed or optically characterized in such a way that it is in direct physical contact with the

[0024] object, but is delimited from the objective by the membrane. The term "membrane" here refers to an object which is formed by a flexible solid body which essentially has a two-dimensional extent and a thickness, wherein the extent exceeds the thickness by a factor of at least 10, preferably at least 50, in particular at least 100. In a preferred embodiment, the membrane is in the form of a thin, flexible film which can preferably have a thickness of 10 µm to 250 µm, particularly preferably 15 µm to 100 µm, in particular 25 µm to 50 µm. The thin, flexible film can preferably be automatically fed in and removed via an arrangement of rollers or sliding surfaces.This makes it possible, when changing the object, to remove a membrane area contaminated by, for example, adhering residues of a first immersion liquid or photoresist from an interaction area of ​​the object and replace it with a new membrane or a new membrane area without adhering substances. Alternative embodiments for the membrane include, for example, ultra-thin glass (engl. . ultra-thin glass) or thin plates made of other optically transparent and mechanically flexible substances. The membrane can in particular cause a delimitation of the first immersion medium, which is in direct physical contact with the object, in the direction of the objective. This makes it possible for the liquid photoresist to cover the object while an exit window or an end face of the objective is in air or is introduced into a second immersion medium, in particular a second immersion liquid. This can in particular prevent unwanted crosslinking of the photoresist on the exit window of the objective during direct-writing laser lithography or the deposit of contaminants from the photoresist on the objective. Furthermore, contamination of the objective or the second immersion medium in contact with it via the object can be avoided.Furthermore, the risk of cross-contamination can be avoided when changing the object.

[0025] In a preferred embodiment, the membrane can be selected so that it is impermeable to the media or components of these media in contact with it and that it is not chemically attacked by these substances even after prolonged or continuous exposure.

[0026] The term "axial mobility" of the partial region of the membrane penetrated by the light describes a configuration of the device in which the axial position of the partial region relative to the objective and / or the object can be adjusted. In a particular configuration, the axial position of the partial region of the membrane penetrated by the light relative to the object can be varied over a range that is preferably more than 20%, particularly preferably more than 40%, very particularly preferably more than 60% of the nominal working distance of the objective. In a further configuration, the axial position of the partial region of the membrane penetrated by the light relative to the objective can be varied over a range that is preferably more than 20%, particularly preferably more than 40%, very particularly preferably more than 60% of the nominal working distance of the objective.

[0027] Particularly in the context of the optical processing of the object, preferably in a lithography process, the term "immersion medium" refers to a solid or liquid substance or a gel-like mixture through which the light beam passes before a polymerization reaction is initiated, preferably near the focal point of the light beam. According to the present invention, a liquid photoresist itself can serve as the immersion medium, or layered arrangements can be used, which can comprise a solid photoresist applied to a substrate and one or more layers of immersion oils or transparent platelets, which, however, are not part of the present invention.

[0028] Analogously, particularly in the context of the optical characterization of an object, an "immersion medium" is understood to be a solid or liquid substance through which the light beam used for imaging passes on its path between the objective lens and the object. This can be a liquid substance, such as an immersion oil or a photoresist, or a solid substance, such as a glass, a polymer, or a mixture or combination of polymers. These materials can, for example, be present in the form of a plane-parallel layer or surround the object to be examined on the objective side. When combining optical processing with optical characterization of the object, the photoresist used for lithographic structuring can also serve as an immersion medium for imaging.The term "photoresist" refers to a photosensitive material, preferably a polymer belonging, for example, to the group of acrylates, methyl methacrylates, epoxides, or ormocers. For exposure, a wavelength of the electromagnetic spectrum is selected that matches the absorption properties of the selected photosensitive material, preferably in the visible, infrared, or ultraviolet spectral range. Exposure of the photoresist to the light beam can cause a change in a property of the photosensitive material, in particular a change in the solubility of exposed portions of the photosensitive material. Depending on the selected material, the solubility may decrease (so-called "negative-tone photoresist"). negative-tone photoresist) or increase (so-called "positive tone photoresist"). positive-tone photoresist ) .Depending on the type of change, the exposed partial areas of the light-sensitive material in the positive tone photoresist or the unexposed partial areas of the light-sensitive material in the negative tone photoresist can be removed in a development step following the at least one exposure step, whereby the desired structure on the object can be obtained.

[0029] Because the membrane is inserted between the lens and the object, it reduces the usable working distance on the object side, which is particularly disadvantageous during lithographic processing or the optical characterization of objects with strong surface topography, such as optical multi-chip modules. The term "usable working distance on the object side" or simply "usable working distance" d" is used below to refer to the distance between the focal plane of the lens and the optical or mechanical component closest to the focal plane in the direction of the lens, such as the membrane. The reduction in the usable working distance on the object side can be minimized by choosing a thin membrane.In a preferred embodiment, the thickness of the membrane can be selected to be thinner than one-third of the working distance, more preferably thinner than one-sixth of the working distance, in particular thinner than one-tenth of the working distance. For an exemplary objective having a working distance of 300 µm, the thickness of the membrane can thus preferably be selected to be at most 100 µm, more preferably at most 50 µm, in particular at most 30 µm. A loss of rigidity associated with a thinner membrane can be compensated for by introducing tensile forces acting in a lateral direction into the membrane, preferably by means of a tension ring or tension rollers that are integrated into the membrane holder or that form the membrane holder. This makes it possible to provide very flat optical interfaces, even with very thin membranes, whose effect on the phase fronts of the light penetrating them is very precisely known.

[0030] The light used for lithographic processing or for optical characterization of the object, which can in particular be a laser beam, can be coupled into or out of the immersion medium adjacent to the object through at least the transparent portion of the membrane. The term "transparent" refers to a property of at least the portion of the membrane that consists in low transmission attenuation across a wavelength range of the light used for processing or characterization, with the transmission attenuation preferably being less than 1 dB, particularly preferably less than 0.25 dB, and in particular less than 0.1 dB.The transparent portion of the membrane can either form a well-defined optical interface, the effect of which on the phase fronts of the light penetrating it is precisely known and can thus be compensated for by corresponding aberrations in adjacent spatial regions, or it can behave "optically neutral." The term "aberrations" refers to deviations from an ideal optical image, which would lead to ideal, error-free imaging or to the smallest possible focus volume of the light beam used for optical characterization or lithographic processing. On the one hand, these can be geometric or monochromatic aberrations, which result from the geometric-optical beam paths and the refractive indices occurring along these beam paths and which already occur in monochromatic lithography or lithographic processing.Imaging light, and chromatic aberrations resulting from a wavelength dependence of the refractive indices of the materials present in the beam path. The term "optically neutral" describes that the geometric aberrations caused by the transparent portion of the membrane are negligible. Optical neutrality can preferably be achieved by using a very thin membrane, at least in the transparent portion, which is in contact with an immersion medium on both sides, or by using a membrane that, in the transparent portion, does not differ, or differs only slightly, from the adjacent immersion media on either side in terms of refractive index in the wavelength range relevant for optical structuring or characterization.In the case of a transparent partial region of the membrane which is optically neutral in this sense, the disturbance of the phase fronts penetrating the partial region can preferably be equal to or less than λ / 4, particularly preferably less than λ / 10, in particular less than λ / 20, wherein the disturbances of the phase front are given as an equivalent path difference in fractions of a wavelength λ.

[0031] The membrane is attached to a membrane holder and has a partial area that is transparent to the light used to characterize or process the object, wherein in a preferred embodiment, its axial position relative to the objective can be adjusted by means of at least one positioning element, in particular during the writing process.In this case, both the membrane and the membrane holder are attached at a point outside the lens, which means that neither the membrane nor the membrane holder are attached to the lens itself, whereby the term "not attached to the lens" means that there is no direct, force-fitting, form-fitting and / or material-locking mechanical connection in all spatial directions between the membrane or the membrane holder and a component of the lens, in particular a mount, a housing or a transparent element of the lens, via which forces acting on the membrane are transferred completely or primarily to the lens.The proposed design of the membrane and the membrane holder prevents the forces exerted by the immersion medium or the photoresist on the preferably large-area membrane during a relative movement of the membrane and the object from being transferred directly and without attenuation to the lens, which could thus complicate highly precise dynamic positioning of the lens. Instead, the membrane holder can be attached to another part of the optical characterization or processing unit. Unlike the lens, this other part is not part of the optical beam path, in which the requirements for precision and dynamic positioning are lower, and this other part can absorb at least some of the forces acting on the membrane.A time-averaged amount of the forces transmitted from the membrane to the lens can preferably be less than 60%, particularly preferably less than 40%, and most preferably less than 30% of the corresponding averaged amounts of the total forces acting on the membrane. The further part of the optical characterization or processing unit can preferably be a positioning table with which the lens can be moved axially and / or laterally and which is also referred to below as the "lens table." Thus, the membrane and the membrane holder can be mounted immovably with respect to the lens without the membrane or the membrane holder exerting forces on the lens itself. Alternatively, the membrane holder can also be attached to another part of the optical characterization or processing unit that cannot be moved axially with the lens.This can, in particular, be the specimen slide or a stage supporting the specimen slide. Furthermore, it is also possible to attach the membrane holder to an object transport unit suitable for protecting and transporting the object, for example, designed as a closed container. This object transport unit can preferably comprise the specimen slide, the membrane holder, and the membrane.

[0032] A further advantage of a membrane that is not attached to the lens is that it allows the lens to be removed or replaced with another one without removing or modifying the membrane or the membrane holder. This is particularly advantageous in an optical characterization or processing unit that has an automatic lens change capability or is designed to accommodate different lenses, including lenses from different manufacturers. In this case, it is desirable to provide a mechanism for attaching the membrane holder that is independent of the mechanical design of the lens.A further advantage of a membrane that is not attached to the lens is that the membrane can be changed easily and automatically, preferably by pivoting or retracting it laterally, without exerting forces on the lens that could adversely affect beam alignment. In particular, it is possible to change the membrane without having to move the membrane or the associated membrane holder significantly in the axial direction towards the object, thereby risking damage to the object. Furthermore, the proposed attachment of the membrane prevents additional masses from being attached to the lens, which could generate forces and / or vibrations during rapid movement of the lens in the axial or lateral direction and thus impair the quality of the optical imaging or lithographic structuring.

[0033] However, lenses with a short working distance have the disadvantage that the use of the diaphragm and the associated diaphragm mount can severely restrict the available space between the lens and the object. The present device is therefore designed to limit the usable working distance of the lens as little as possible. It can therefore also be applied to lenses with a high numerical aperture (NA) and a short nominal working distance, which can be realized compactly with a comparatively small diameter and low weight, but for which the available space between the lens and the object is severely restricted. At the same time, the present device should make it possible to keep the usable working distance on the object side as large as possible.The "object-side usable working distance," the "usable working distance," or simply the "working distance" refers to the distance between the focal plane of the lens and the optical or mechanical component closest to the lens; the nominal working distance refers to the distance between the focal plane and the component of the lens closest to it, for example, the exit window. The NA of a lens used in the proposed device can preferably be more than 0.5, particularly preferably more than 0.7, more preferably more than 0.9, and especially more than 1.1. The nominal working distance of the lens can range from 50 µm to 10 mm, preferably from 80 µm to 2 mm, and especially from 100 µm to 1 mm.

[0034] The device is designed such that, apart from the membrane itself, no further mechanical elements are introduced into the space between an end face of the lens and the object. The term "lens" refers to a focusing element or an arrangement of at least two focusing elements configured to radiate light into the object space or to receive light from it. In general, the lens can have at least one end face, an edge of the end face, an exit window, and a mount, whereby further components can also be provided. According to the present invention, the term "lens" encompasses, in addition to the at least one focusing element, in particular a housing, which is configured, for example, for mechanically mounting the at least one focusing element.The lens and the associated optical system also have an optical axis, which results, for example, from the rotational symmetry of the optical surfaces within the lens. The design of the lens housing is not taken into account when determining the optical axis. The term "end face" refers to a surface of the lens facing the object, which includes an "exit window" of the lens in the form of a transparent portion, through which light can be emitted in the direction of the object or received from that direction. An "exit window" refers to an optically transparent window integrated into the lens or connected to it by direct physical contact, through which light can enter or be received from an immersion medium adjacent to the lens.The end surface can comprise a flat or curved surface of the exit window and a surface surrounding the exit window of a non-transparent mechanical mount, which has a ridge line. The term "mount" refers to a mechanical element that determines the outer geometric shape of the lens, which directly adjoins the exit window and can encompass the entire housing of the lens. However, for the present invention, only the part of the mount facing the object is relevant. The object-side part of the mount comprises all surface elements of the mount whose normal vector has an axial component pointing toward the object. A "ridge line" of the mount is understood to be a contour enclosing the optical axis, which is formed by the points parallel to the optical axis that protrude furthest toward the object.Using the ridge line of the mount, the term "end surface" can thus be defined as follows: The end surface comprises at least the exit window of the lens, whereby in the case of a mount adjoining the exit window, the end surface also comprises the area of ​​the mount enclosed by the ridge line as well as all points outside the ridge line which, in the case of a flat surface of the object aligned perpendicular to the optical axis, have a distance . d' to the object, which is preferably less than 5 mm, particularly preferably less than 1 mm, in particular less than 300 µm greater than the maximum distance of your point on the ridge line to the surface of the object. The end face of the lens thus forms a simply connected area that has a boundary. The points on the end face closest to the object do not necessarily have to lie on the ridge line of the mount. For example, in the case of a convexly curved exit window of the lens, the points closest to the object can lie on the exit window itself.

[0035] In order to enable stable support and axial positioning of the portion of the membrane penetrated by the light, even without mechanical elements between the end face of the lens and the object, the proposed device comprises a membrane holder connected to the membrane. According to the invention, the contact points between the membrane and the membrane holder are located on or outside a lateral surface, which is described by a geometric extrusion of the edge parallel to the optical axis, and wherein an arrangement of the contact points between the membrane and the membrane holder within this lateral surface is excluded. The term "lateral surface" here describes the surface formed by the geometric extrusion of the edge of the end face parallel to the optical axis.It can also be understood as the enveloping surface of a cylindrical body resulting from a geometric extrusion of the end face along the optical axis of the system. Depending on the contour of the boundary, it can assume any cross-section, particularly in the form of a circle, an ellipse, or an oval. However, other cross-sectional shapes are possible. The term "geometric extrusion" generally refers to an increase in the dimensions of an element—here the boundary or end face—through parallel displacement in space, here parallel to the optical axis. If the boundary of the lens's end face, representing a line or curve, is extruded by drawing the line or curve along a direction parallel to the optical axis, the desired enveloping surface can be obtained.This design of the present device makes it possible to advantageously use the installation space available on or outside the lateral surface in the axial direction for designing the membrane holder, without the usable working distance of the device being restricted by mechanical elements which, according to the prior art, would be introduced between the end surface of the objective and the object.

[0036] In a preferred embodiment, the diaphragm can be positioned very close to the lens, so that the reduction in the usable working distance of the device compared to the nominal working distance of the lens is essentially determined by the thickness of the diaphragm. In a further preferred embodiment, tensile forces can be introduced into the diaphragm by the diaphragm holder, which act in a plane perpendicular to the optical axis and which make it possible to tighten the diaphragm and thus achieve the most flat shape possible for the diaphragm even in the case of a very thin diaphragm. The diaphragm holder can be annular and introduce tensile forces into the diaphragm that are directed radially away from the optical axis, or arrangements can be used that introduce tensile forces into the diaphragm that are directed essentially parallel.The term "radial" refers to a direction perpendicular to the optical axis; a direction parallel to the optical axis is described by the term "axial." The membrane mount can have rollers and / or sliding surfaces, thus enabling lateral movement of the membrane between the end face of the objective and the specimen. This can be advantageous for easier changing of the portion of the membrane surface in contact with the immersion medium.

[0037] In a particularly preferred embodiment, the proposed device has a device for adjusting the axial position of the partial area of ​​the membrane penetrated by the light relative to the object during the characterization or processing process. For this purpose, a single- or multi-part positioning element is used, which can be brought into contact with the membrane. The term "during the characterization or processing process" refers to a change in the axial positioning of the partial area of ​​the membrane penetrated by the light beam relative to the object, which occurs automatically during lithographic structuring or three-dimensional optical characterization or during a brief interruption of these processes, without requiring the object to be removed from the working space of the lens, for example, to perform a calibration.The axial mobility of the portion of the membrane penetrated by the light beam relative to the object results in the advantage of direct-writing laser lithography processes: even lenses with a limited nominal working distance or devices with a limited usable working distance can be used to create structures of any height by moving the lens and the membrane together away from the object during the layer-by-layer construction of the structure. Furthermore, the axial positioning of the portion of the membrane penetrated by the light beam can result in a further advantage of an additional degree of freedom for compensating for optical aberrations compared to lithography processes in which the lens is in direct contact with a homogeneous photoresist to be patterned.For this purpose, immersion media of different photosensitivity and / or refractive indices and / or viscosities can preferably be used. These immersion media are introduced into spatial regions adjacent to the membrane sections penetrated by the light on the object side and / or the objective side. In this case, an axial displacement of the membrane section penetrated by the light beam makes it possible to specifically generate or compensate for aberrations. Multiphoton luminescence radiation, which is generated in the volume of the immersion medium by the light beam used to characterize or process the object and which can be detected by a detection device present in the lithography unit, can serve as an indication of the presence of a favorable axial position of the membrane.In the case of multiphoton luminescence, the intensity of the generated luminescence radiation depends nonlinearly on the excitation intensity and can be described by a characteristic curve of positive curvature. Since a high maximum intensity is achieved in the object space with small aberrations, the luminescence is also maximum at minimal aberration. By maximizing the detected luminescence power, the aberration can be minimized. By moving the membrane and simultaneously observing the luminescence, an optimal position for the membrane can be found by maximizing the luminescence. To detect the luminescence radiation, the lithography unit can be supplemented with a luminescence detection device.In a preferred embodiment, the power of the light used to excite the multiphoton luminescence is selected such that no crosslinking reactions or only very weak crosslinking reactions are triggered upon excitation. A "crosslinking reaction" in this context is understood to be a chemical reaction in which permanently stable covalent bonds are formed between reactants contained in the immersion medium. The resulting reaction products preferably have at least one higher molar mass than each of the reactants involved in the reaction. Thus, the photoresist remains unchanged during the membrane position adjustment process, or the photoresist changes only to a negligible extent compared to the subsequent patterning.

[0038] In a further preferred embodiment of the device, a collision between two elements of the device can be detected via a sensor, for example a force sensor or a contact sensor based on electrical currents. The detection of such a collision, which can occur in particular between the membrane holder or membrane and the object, slide, or stage, allows appropriate protective mechanisms to prevent a collision and resulting damage to the lens or other sensitive components.

[0039] A further advantage of using a portion of the membrane through which the light beam passes and is movable in the axial direction relative to the object is the reduced consumption of photoresist material in 3D direct-writing immersion lithography. By axially positioning the portion through which the light passes as close as possible to the object, the volume of photoresist serving as the immersion medium between the membrane and the object can be reduced to a minimum, while on the side of the membrane facing the objective, another immersion medium, e.g., an index oil, can be used that can be reused multiple times. By adjusting the axial position of the portion of the membrane through which the light beam passes during operation, the volume of photoresist can be flexibly adapted to the structure to be created.Additionally or independently, lateral localization of the photoresist can be achieved through interaction between the membrane and the photoresist serving as the immersion medium. For example, a membrane with adapted wetting properties, especially with small volumes of photoresist, can prevent a drop of photoresist from "flowing" laterally by holding the photoresist between the membrane and the object through surface forces. Lateral structuring on the membrane can also contribute to this, as it can change the membrane's wetting properties, particularly in a spatially resolved manner. The lateral structuring can be applied both on the side of the membrane facing the object and on the side facing the objective and can be used for the spatially resolved application of immersion media.In addition or alternatively, for lenses with a large nominal working distance, additional guide elements can be used to prevent the lateral flow of immersion fluids. In a special design, these guide elements can also be formed by the positioning elements.

[0040] The use of two immersion media separated from each other by the axially movable, transparent portion of the membrane can also result in additional degrees of freedom with regard to the photosensitivity and / or the refractive index and / or the viscosity of the immersion fluid in direct contact with the object. Immersion objectives are typically optimized to a specific refractive index that either homogeneously fills the object-side beam path or surrounds a cover glass with specified thicknesses and optical properties in order to achieve minimal geometric aberrations and thus the greatest possible spatial concentration of the optical power at the focal point. When using such objectives in direct-writing, high-resolution laser lithography, it is therefore important to precisely match the refractive index of the photoresist serving as the immersion fluid to the objective used.This requires adjusting the refractive index, typically with an accuracy of 10 -3 or better. This not only severely limits the range of usable photoresists, but can also cause problems when implementing stable lithography processes in an industrial environment. For example, fluctuations in the refractive index of the magnitude mentioned can be caused by temperature dependence or aging of the photoresist, or by fluctuations in the composition of the starting materials used to produce the photoresist. Furthermore, lenses can also have manufacturer-specific tolerances that necessitate the use of lens-specific immersion media, especially photoresists, which is difficult to implement in an industrial context. These problems can be solved by the locally axially movable, transparent membrane proposed here.By separating the volumes of immersion media between the objective and the object, the area facing the object can be wetted with a photoresist, serving as the first immersion fluid, whose refractive index is not optimally matched to the objective. The resulting aberrations can be compensated for by a suitable choice of the second immersion medium, which is used on the side of the membrane facing the objective and whose refractive index is selected for this purpose.In addition to the selection of the refractive index of the second immersion medium, which can differ from the refractive index of the first immersion medium, in particular by a difference of at least 0.005, preferably by at least 0.01, the proposed option of axially positioning the portion of the membrane penetrated by the light beam between the objective and the object can also be used to adjust all aberrations occurring along the beam path as precisely as possible. This allows not only geometric aberrations but also chromatic aberrations to be compensated by selecting a second immersion medium with a suitable wavelength dependence of the refractive index or a suitable Abbe number.Similarly, a suitable choice of the second immersion medium allows for compensation of a temperature dependence of the refractive index of the first immersion medium and thus the resulting geometric aberrations. Alternatively or additionally, the viscosities of the first immersion medium and the second immersion medium can preferably differ from each other. To create additional degrees of freedom in compensating for aberrations or temperature dependencies, it is possible to provide at least one additional membrane, adjustable in axial position, between the object and the objective, between which additional immersion media of different refractive indices and Abbe numbers can be inserted.

[0041] The at least one positioning element used for the axial positioning of the portion of the membrane penetrated by the light can act either on the entire membrane or only on the portion penetrated by the light. For this purpose, the at least one positioning element can be in permanent mechanical contact with the membrane. Alternatively, this contact can be established before the start of the optical structuring or characterization process, for example, during a mutual approach of the lens and object.In the event that the at least one positioning element acts only on the partial area penetrated by the light beam, the second contact points between the at least one positioning element and the membrane can preferably lie within a contour that can be described by the above-described first contact points of the membrane with the membrane holder or by a polygon formed by the first contact points with non-overlapping side lines. The at least one positioning element can furthermore be designed such that it does not interfere with the light beam used to structure or characterize the object as far as possible. For this purpose, the second contact points between the membrane and the at least one positioning element can preferably lie outside the partial area penetrated by the light beam.In a preferred embodiment, the at least one positioning element is designed such that the second contact points between the membrane and the positioning element lie on or outside the lateral surface, which is described by the geometric extrusion of the edge of the end face of the lens parallel to the optical axis of the system. This also makes it possible here to use the installation space available on or outside the lateral surface in the axial direction to design the at least one positioning element, without restricting the usable working distance of the arrangement by mechanical elements between the end face of the lens and the object. The contact points between the membrane and the at least one positioning element can be discrete individual points or a set of points, which can preferably form a single-part or multi-part contour enclosing the optical axis.In a preferred embodiment, it is possible to adjust the axial position of the partial area of ​​the membrane penetrated by the light beam over a wide range by means of the at least one positioning element, so that the membrane can be brought as close as desired to the end surface of the objective as well as as close as desired to the surface of the object.

[0042] In a particular embodiment, the at least one positioning element can be designed such that it has no positive, non-positive, and / or material-locking connection to the membrane at the contact points in the lateral direction and can thus absorb predominantly axially acting forces from the membrane. For this purpose, the at least one positioning element can in particular be designed such that it can be moved laterally over the membrane, whereby an optimal axial position of the partial area of ​​the membrane penetrated by the light beam with respect to the lens or the object can be achieved at least temporarily, preferably continuously. For this purpose, the at least one positioning element can be designed such that it can slide or roll laterally over the membrane without great force being exerted as a result of friction and without great wear on the membrane or on the at least one positioning element itself.Alternatively or additionally, the rollers and / or sliding surfaces of the at least one positioning element can also serve to enable a lateral movement of the membrane and thus a simple change of the part of the surface of the membrane in contact with the immersion medium, for example in order to prevent contamination.

[0043] To position the partial area penetrated by the light, a movement of the contact points or of the at least one positioning element in the axial direction relative to the object is possible, which is effected either by specially provided actuators or by an arrangement in which the at least one positioning element is attached to another part of the lithography unit and can be moved together with it by existing actuators. To enable an axial movement of the partial area of ​​the membrane penetrated by the light beam by means of the forces introduced by the at least one positioning element, the membrane holder can have mechanical degrees of freedom, which preferably allow axial sliding of an element firmly connected to the membrane relative to a stop point of the membrane holder.Alternatively or additionally, the axial mobility of the part of the membrane penetrated by the light beam can also be based on an elastic or partially elastic deformation of the membrane and / or the membrane holder.

[0044] The at least one positioning element or an associated actuator used for the axial positioning of the partial area penetrated by the light beam can be attached to a part of the lithography unit or integrated into the object transport unit, which is preferably designed as a closed container and is provided for the protection and transport of the object. In a particular embodiment, the at least one positioning element can be attached to the objective lens or the objective stage. In this case, the at least one positioning element can have actuators configured to displace the partial area of ​​the membrane penetrated by the light beam in the axial direction relative to the objective lens or the objective stage.Alternatively, the at least one positioning element can be rigidly connected to the lens or to the lens stage and positioned in the axial direction together with the lens or to the lens stage in a synchronized movement effected by the same actuator. In this case, an adjustment of an axial position of the partial area of ​​the membrane penetrated by the light beam between the lens and the object, which is favorable for characterizing or processing the object, can take place during a mutual approach and a highly precise relative positioning of the lens and object. In a simple embodiment, a part of the lens itself can also assume the role of the at least one positioning element, for example by pressing a lens with a flat or concave end surface onto a laterally tensioned membrane in order to slightly deform and / or displace it in the axial direction.The part of the lens acting as the positioning element can be, for example, the ridge line or the edge of the lens end face, or a portion of the lens end face located between the ridge line and the edge of the lens. Furthermore, a lens with a flat exit window or one that is convexly curved toward the object can be used to position the portion of the diaphragm through which the light passes, provided the exit window is closer to the object than the lens mount. In the case of a flexible diaphragm, the diaphragm can conform to the exit window, which, in the case of a thin, optically neutral diaphragm, does not lead to any relevant additional aberrations.If the at least one positioning element is attached to the lens as described above, it is advantageous if the forces acting on the lens from a large-area membrane can be at least partially diverted via a membrane holder that is not attached to the lens instead of being completely transferred from the positioning elements to the lens. This can be made possible on the one hand by the positioning elements not having a positive, force-fitting and / or material-locking connection to the membrane in the lateral direction and can therefore primarily absorb axially acting forces from the membrane. These axially acting forces can be minimized by tightening the membrane by forces introduced by means of a lateral, robustly designed membrane holder and by the positioning elements attached to the lens being pressed onto the membrane with small forces in the axial direction.This makes it possible, in particular, to design the at least one positioning element compactly and thus keep the additional masses attached to the lens as low as possible with a view to rapid and precise movement of the lens. In an alternative embodiment, the at least one positioning element can be attached to the specimen slide, the specimen stage, or other parts of the lithography unit. They can preferably have actuators with which the portion of the membrane penetrated by the light can be displaced in the axial direction relative to the lens.

[0045] In a particular embodiment, it is possible to ensure that no forces are transferred from the membrane to the lens by avoiding direct contact between the lens and the membrane and by not attaching the at least one positioning element to the lens. This use of a membrane holder not attached to the lens in combination with one or more positioning elements structurally separate from the membrane holder for axially moving the portion of the membrane penetrated by the light makes it possible, in particular, to avoid or at least reduce forces acting on the lens by dissipating a portion of these forces via the membrane holder into another part of the optical processing or characterization unit that is less sensitive to the effects of force.This design is advantageous in that it allows the diaphragm mount to be designed to be massive, allowing for the introduction of large clamping forces into a large-area diaphragm, without increasing the masses and inertial forces directly attached to the lens. The positioning elements, on the other hand, can only allow a small axial deflection of the diaphragm; this requires only small axial forces, which can be applied by the lens and transferred to the diaphragm by relatively small positioning elements. Even if the positioning elements are not attached to the lens itself, the separation of the diaphragm mount or positioning elements is still advantageous, particularly with regard to the possibility of easily replacing the diaphragm or changing the lens without removing or modifying the diaphragm or the diaphragm mount.Nevertheless, embodiments are also conceivable in which the membrane holder itself serves as a positioning element and is preferably attached to the objective stage, to the object carrier, to another part of the optical processing or characterization unit or to the object transport unit suitable for protecting and transporting the object, preferably designed as a closed container.

[0046] As already mentioned, in a preferred embodiment the membrane can be a thin, flexible film that can be tightened by lateral forces and elastically deformed for the axial positioning of the portion of the membrane penetrated by the light beam. The axially acting forces required for deformation can be introduced by appropriate positioning elements, as described above. The use of a membrane tightened by lateral forces and locally positioned by axial forces is particularly advantageous when very large objects are to be processed, the lateral extent of which can be more than 100 or 1000 times the working distance of the objective and for which it would only be possible with considerable mechanical effort to position a large-area membrane at the correct height and with sufficient parallelism to the focal plane of the objective.In a preferred embodiment, the positioning elements used for the local axial positioning of the portion of the membrane penetrated by the light beam are designed such that they can be moved laterally across the membrane, continuously achieving an optimal axial position of the portion of the membrane penetrated by the light beam relative to the objective. For this purpose, the positioning elements can be designed such that they can slide or roll laterally across the membrane without exerting significant force due to friction and without significant wear on the membrane or the positioning elements.

[0047] In a particularly preferred embodiment, the large-area flexible membrane can comprise an elastic film made of a material that is resistant to the immersion media or photoresists used and that allows for stretching. Suitable materials include a polymer, particularly polyethylene (PE) or polyimide (PI), nylon (polyamide), or very thin, flexible glass films. Ultra Thin Glass), as described, for example, by F. He et al., Towards Flexible Glass: Ultra-Thin Glass with Tight Dimensional Tolerance and High Strength Achieved by Ion Exchange, SID Symposium Digest of Technical Papers, 2017, page 48. The membrane holder can preferably be designed as a clamping ring, which allows for a wrinkle-free membrane path. Alternatively, an arrangement of rollers and / or sliding surfaces can be provided, particularly for the automatic removal of contaminated areas and the introduction of clean areas of the membrane.

[0048] In a preferred embodiment for multiphoton lithography applications, the membrane can comprise a material that is transparent in the wavelength range of a short-pulse laser used for lithographic processing, but opaque in the wavelength range to which the photosensitive material or photoresist is sensitive due to linear (single-photon) absorption. The membrane can thus offer protection against unwanted exposure of the photoresist to ambient light, while still allowing processing by multiphoton polymerization with the short-pulse laser. Integrating the membrane into an object transport unit makes it possible to transport the object transport unit through areas where there is no so-called yellow light; i.e., where the UV components of the ambient light are not filtered out.A corresponding spectrally selective transmission of the membrane can be provided, for example, by the inherent material properties of the membrane, or it can be achieved, for example, by adding appropriate materials or by suitable coatings, for example vapor-deposited or applied in the liquid phase, which can at least partially reflect and / or at least partially absorb UV components of the light.

[0049] In a preferred embodiment, the membrane can be mounted laterally immobile with respect to the object, while the axial mobility of the membrane or at least of the portion of the membrane penetrated by the light beam is not impaired.

[0050] This configuration is particularly advantageous when structures are to be lithographically generated or optically characterized whose lateral dimensions are larger than a field of view or a write field of the lens addressable by a beam scanner, which requires lateral movement of the lens relative to the object. A fixed lateral position of the membrane relative to the object prevents shear forces from being introduced into the immersion medium or photoresist in contact with the object during lateral movement, which could lead to relative movement of the object and the layers of the immersion medium adjacent to the object, thus damaging structures on the object.Instead, the shear forces can be introduced into the immersion medium located between the membrane and the objective lens. This medium is not in contact with the object and thus cannot cause damage to the object or any structures on it. The immersion medium can also have a low viscosity to minimize the forces acting on the objective lens during lateral movement. Alternatively, no immersion medium can be provided if the objective lens is a dry objective. In this case, the membrane can help create a well-defined, optical-quality interface through which the light beam can be coupled into or out of the immersion medium or photoresist without interference.Advantageously, a laterally immobile mounting of the membrane relative to the specimen can be achieved, preferably by fixing the membrane holder to the specimen slide or stage or by integrating it into an object transport unit. The axial mobility of the portion of the membrane penetrated by the light beam can preferably be achieved by elastic deformability of the membrane itself or the membrane holder.

[0051] In a further embodiment, which is not part of the present invention, a lithographic patterning can be performed using an air lens in a solid photoresist whose surface may have a strong topography and therefore cannot serve as a defined optical interface. The solid photoresist may be materials such as polymethyl methacrylate (PMMA), SU-8, Ormocere, or substances related to these materials. For further details regarding the material "SU-8," reference is made, for example, to the description in http: / / www.microchem.com / pdf / SU8 50-100.pdf(accessed on December 7, 2018). For this purpose, a first immersion liquid can be applied to the solid photoresist, whose refractive index is matched to the photoresist. This first immersion liquid is delimited in the direction of the objective lens by the membrane with a defined optical surface, thus enabling low-interference coupling of the light used for lithographic structuring and emitted by the dry objective lens into the solid photoresist – even in the case where the photoresist has a strong surface topography.

[0052] Similarly, this arrangement also allows high-resolution imaging of structures buried in the photoresist. Alternatively, a second immersion fluid can be used between the membrane and the objective lens. This second immersion fluid may have a different refractive index and / or viscosity than the first immersion fluid and thus also than the solid photoresist. In this case, the refractive index and / or viscosity of the second immersion fluid, as well as the position of the interface defined by the membrane, can preferably be selected such that the beam path between the objective lens and the object exhibits minimal geometric aberrations, thus achieving the greatest possible spatial concentration of the optical power at the focal point.

[0053] For further details regarding the proposed device, reference is made to the embodiments below.

[0054] In a further aspect, the present invention relates to a method for optically processing an object, which can be carried out in particular by means of the device for optically processing an object also described herein. The method comprises the steps a) to f) described in more detail below, wherein each individual step can also be performed multiple times and at least successive steps can also be carried out at least partially simultaneously: a) positioning at least one object on a slide; b) applying an immersion medium to at least a portion of the object, wherein the immersion medium is in the form of a liquid photoresist; c) bringing a membrane closer to the portion of the object covered with the immersion medium, wherein the membrane has a transparent portion provided for the penetration of light; d) positioning an objective lens defining an optical axis relative to the portion of the object covered with the immersion medium; e) setting an axial position for the portion of the membrane with respect to the optical axis; and f) optically processing the object using the light.

[0055] According to step a), at least one object is first placed on a slide.

[0056] As described above or below, the object can be a single object or an object that includes several sub-objects.

[0057] According to step b), an immersion medium is applied to a portion of the object to be optically characterized or processed. This can be done manually or by means of a technical device, in particular a dispensing unit. The dispensing unit can be located directly in the optical characterization or processing unit or be provided as a standalone device from which the object coated with the immersion fluid can be transferred to the optical characterization or processing unit. The immersion medium is a liquid photoresist.

[0058] According to step c), a membrane is brought closer to the part of the object covered with the immersion medium. For this purpose, the membrane can in particular be attached to a membrane holder. The membrane has a partial area that is transparent to the light used to characterize or process the object and serves to delimit the immersion liquid in contact with the object in the direction of the objective. The partial area of ​​the membrane penetrated by the light is designed to be movable in the axial direction relative to the object. As described further, both the membrane and the membrane holder are attached to a location outside the objective; such that neither the membrane nor the membrane holder are attached to the objective itself.Furthermore, first contact points between the membrane and the membrane holder are located on or outside a lateral surface, which is formed by a geometric extrusion of the edge of the end face of the lens parallel to the optical axis. Depending on the embodiment, the membrane can approach the portion of the object covered with the immersion liquid either in the optical characterization or processing unit itself, in a dispenser unit suitable for applying the photoresist, or in another functional unit suitable for applying the membrane. When the object coated with the immersion liquid is transferred to the optical processing unit, the membrane, in conjunction with an appropriately designed object transport unit, can thus assume the protective function described above and below to prevent contamination or contact with oxygen or air humidity.

[0059] According to step d), a lens, which defines an optical axis in the present optical system, is positioned relative to the part of the object covered with the immersion medium.

[0060] According to step e), an axial position for the partial area of ​​the diaphragm is adjusted as favorably as possible, whereby the term "axial" refers to the optical axis defined by the lens. Positioning elements, as described above or below, can be used for this purpose. The diaphragm is positioned in the working space of the lens, and the portion of the axially movable diaphragm through which the light passes is brought into a desired axial position between the lens and the object.In a particular embodiment, it is possible to perform the axial positioning of the portion of the membrane penetrated by the light beam together with the positioning of the objective relative to the object in a synchronized movement effected by the same actuator. In addition, the axial approach of the membrane to the part of the object covered with the immersion liquid, as performed in step c), can also take place simultaneously. For this purpose, the membrane and the membrane holder can preferably be attached to the objective stage and moved toward the object together with the objective.

[0061] Finally, according to step f), the object is optically processed using the light beam.

[0062] In a preferred embodiment of the present method, steps a) to c) can be carried out in a dispenser unit configured to apply the immersion medium used between the membrane and the object. Following this, an object transport unit, which, in addition to the membrane and the membrane holder, comprises at least the object slide or is configured as a object slide, can be transferred to an optical characterization or processing unit. Steps d) to f) can then be carried out in the optical processing unit, also referred to below as the "lithography unit." In this way, the automated application of the immersion medium to the object, the transfer of the object provided with the immersion medium, and the optical processing can take place within a production chain in separate functional units specially designed for the respective function.This advantageously enables the application of a liquid photoresist in a separate functional unit and subsequent transfer within a production chain, particularly for transport between different functional units, using the membrane as part of a container enclosing the object. Especially for transport between functional units, it can be particularly advantageous if the membrane is transparent to light at the wavelength used for processing and / or characterization, but not at shorter wavelengths, so that, as described above, ambient light cannot trigger inadvertent polymerization of the photoresist, particularly when using multiphoton lithography.

[0063] A further aspect, which is not part of the present invention, relates to an object transport unit comprising a slide for receiving an object, at least one membrane inserted between an objective and the slide, wherein the membrane has a partial area designed for the penetration of light, wherein at least the partial area of ​​the membrane is movable in the axial direction with respect to the optical axis, and at least one membrane holder for holding the at least one membrane, wherein the object transport unit is transferable at least between a handling unit for immersion media and a device for the optical characterization or processing of an object, in particular a device for the optical processing of an object as described herein, wherein the handling unit is configured at least for applying an immersion medium used between the membrane and an object to be characterized or processed, and wherein the optical characterization or processing unit comprises at least one device for generating or receiving the light and the lens for exposing the object by means of the light or for detecting the light from the object.

[0064] Here, the term "handling unit" refers to a device configured to provide, store, transport, and dispense at least one immersion medium. For this purpose, the handling unit can, in particular, have a dispensing unit with which the immersion medium is applied to the object. The handling unit can further be configured to surround the object provided with the immersion medium with the object transport unit, which is preferably designed to be liquid-tight, in particular as a closed container. Transport of the object or the object transport unit from the handling unit to the optical characterization or processing unit can preferably be carried out by means of a conveyor system under normal ambient conditions.The term "normal ambient conditions" means that in the space crossed there are no requirements with regard to cleanliness, in particular no clean room class; to lighting, in particular no yellow light environment; to atmospheric conditions, in particular no regulated air humidity and / or to electrostatic discharge, in particular no protection against electrostatic discharge (ESD). electrostatic discharge, ESD) are required.

[0065] For further details regarding the present method and the object transport unit, reference is made to the description of the device and to the embodiments.

[0066] The present device and method have a number of advantageous differences compared to US 2005 / 0158673 A1, which discloses a device for 2D immersion lithography in which the immersion liquid is encapsulated in a balloon formed from a thin membrane. The balloon filled with immersion liquid is positioned between the objective and the object in such a way that it touches both the objective and the object. This allows an immersion objective to be used for high-resolution 2D lithography and protected from contamination. However, applying this disclosure to direct-writing 3D lithography would be associated with far-reaching limitations.The use of a liquid photoresist is ruled out, as it would be displaced from the object by the pressure of the liquid-filled balloon. Even with a solid photoresist, its application is limited to cases where the photoresist has a very flat surface of optical quality, allowing a smooth transition of light from the balloon into the photoresist. This inherently limits the height of the structures that can be produced. Furthermore, the filled balloon exerts forces on the lens that complicate fast and precise relative positioning between the object and the lens, potentially limiting precision and / or writing speed. Furthermore, it cannot compensate for aberrations during structuring at different depths.

[0067] Furthermore, the present device and method have advantageous differences compared to US 7570343 B2. US 7570343 B2 discloses a device and a method for projection lithography in which 2D structures are created on essentially planar objects, which typically have maximum irregularities on the order of one or a few light wavelengths of the lithography radiation. There, it is proposed to insert a closure element that is transparent to the projection light into the object-side light path of the system, wherein the closure element can also serve to separate two immersion liquids. The closure element can be either a solid plate with a macroscopic thickness or a thin membrane, wherein the position of the closure element between the object and the projection lens can be adjusted by appropriate adjustment elements during system setup.The only adjustment elements mentioned are micrometer screws, which can be located in a gap between an end face of the lens and the object. Alternatively, the position of the membrane can be adjusted using the hydrostatic pressure of the adjacent immersion liquids. The closure element can also be used to correct aberrations of the lithography device through a suitable geometric shape. In the case of a flexible membrane, the geometric shape can also be achieved by varying the hydrostatic pressure of the adjacent immersion liquids on either side. However, there is no axial relative movement of the lens to the object during the writing process, as is required in optical 3D processing and characterization to build up or capture a 3D structure layer by layer along the optical axis.This means that it is sufficient to adjust the axial position of the closure element between the lens and the object once during setup of the lithography device, preferably manually using micrometer screws. Changing this position during the writing process by moving the closure element in the axial direction relative to the optical axis defined by the lens is not desired, whereas this is absolutely necessary for direct-writing 3D lithography. This allows the use of large lenses with a long working distance and yet high NA, which have a large mass and are therefore difficult to move quickly and precisely in the axial direction in direct-writing 3D lithography.Since neither the objects nor the substrates nor the structures lithographically produced on them have a three-dimensional topography, it is possible to operate the lithography device with a very small safety distance between the transparent end element and the object, i.e. to reduce the distance between the end element and the surface of the planar substrate coated with a solid photoresist to a very small value, just sufficient to avoid mechanical collisions. Due to the very large working distance of the lens and the very small safety distance necessary for 2D lithographic structuring, it is possible to introduce comparatively large optical and / or mechanical assemblies into the space between the end surface of the lens and the object, which can reduce the usable working distance of the arrangement to a fraction of the nominal working distance of the lens.Another possibility for positioning a transparent closure element designed as a thin membrane is described therein: varying the hydrostatic pressure of the immersion liquid on at least one side of the membrane. However, applying this possibility to 3D direct-writing lithography processes would be subject to significant limitations: On the one hand, it would be necessary to close off the volume of the immersion liquid in such a way that a controlled pressure could be built up and maintained, which would be very complex and difficult to implement in an industrial manufacturing process with short cycle times. Furthermore, the pressure change in the flexible membrane would change not only its position but also its curvature, so that the position and refractive power of the membrane could not be adjusted independently of one another by varying the pressure, which is disadvantageous.Furthermore, a larger volume of immersion fluid would have to be maintained to compensate for the pressure, which, when photoresist is used as the immersion fluid, is disadvantageous in terms of minimizing the photoresist volume. In this case, the photoresist is a solid, thin layer applied to the object, the maximum thickness of which is on the order of one or a few wavelengths of lithography radiation and would therefore be insufficient for producing functional 3D structures. The use of a liquid photoresist as an immersion medium is not planned.Accordingly, there is no risk of unwanted polymerization of the liquid photoresist occurring on the exit window of the lens or of damage to the object or structures created on it due to relative movement between the object and the layers of the liquid immersion medium adjacent to the object. Short description of the characters

[0068] Further details and features of the present invention will become apparent from the following description of preferred embodiments, particularly in conjunction with the dependent claims. The respective features can be implemented individually or in combination with one another. The invention is not limited to the embodiments.

[0069] The exemplary embodiments are illustrated schematically in the following figures. Identical reference numerals in the figures denote identical or functionally identical elements, or elements that correspond to one another in terms of their functions.

[0070] In detail: Figure 1 shows a schematic representation of a preferred embodiment of the device according to the invention; Figure 2 shows a schematic representation of particularly preferred embodiments of an objective for the device according to the invention; Figure 3 shows a schematic representation of an object comprising several sub-objects; Figure 4 shows a schematic representation of several embodiments of membrane holders and positioning elements; Figure 5 shows a schematic representation of a device comprising several devices with separate functions and an object transport unit; Figure 6 shows results of a simulation of the imaging quality of the device according to the invention; Figure 7 shows a schematic representation of a further preferred embodiment of the device according to the invention, which has a second membrane;Figure 8 shows a schematic representation of a further preferred embodiment of the device according to the invention, in which forces for deforming and axially positioning the membrane or its transparent portion are introduced by a positioning element attached to the lens table or to the lens; Figure 9 shows a schematic representation of a further preferred embodiment of the device according to the invention, in which the membrane holder is attached to the lens table; Figure 10 shows a schematic representation of a further preferred embodiment of the device according to the invention, in which the membrane holder is also connected to the lens table; Figure 11 shows a schematic representation of an embodiment not part of the present invention, comprising a solid photoresist covering the object;Figure 12 shows a schematic representation of a further preferred embodiment of the device according to the invention, wherein the membrane has a lateral structure; Figure 13 shows a schematic representation of a preferred embodiment of an arrangement for membrane support and positioning; and Figure 14 shows a schematic representation of an embodiment not part of the present invention, in the form of an object transport unit prior to assembly, in plan view (; Fig. 14a ) and after assembly in top view ( Fig. 14b ) and as a cross-section ( Fig. 14c ). Description of the embodiments

[0071] Figure 1 shows a schematic representation of a preferred embodiment of the device 10 according to the invention for optically processing an object 60. The exemplary in Figure 1The device 10 shown comprises a specimen slide 50 for receiving the specimen 60, an optical unit 15 having a device for generating light, which is provided here, for example, in the form of at least one light beam 140 and can therefore also be referred to as a "lithography unit," and an objective lens 40 for illuminating the specimen 60 by means of the light beam 140, a membrane 100 inserted between the objective lens 40 and the specimen 60, a membrane holder 80 for holding the membrane 100, and an immersion medium 160 inserted between the membrane 100 and the specimen 60. The membrane 100 has a partial region 120 configured for penetration by the light beam 140 used for imaging or processing, wherein at least the partial region 120 of the membrane 100 is arranged to be movable in the axial direction with respect to an optical axis 502, which is defined by the objective lens 40.For this purpose, at least one positioning element 90 can preferably be used in order to be able to move the partial region 120 of the membrane 100 in the axial direction during the processing operation. The objective 40 has an end surface 46 facing the specimen slide 50, wherein the end surface 46 has a border 47. According to the invention, it is proposed to attach the membrane 100 to the membrane holder 80 in such a way that first contact points 81 between the membrane 100 and the membrane holder 80 lie on or outside a lateral surface 510, which is formed by a geometric extrusion of the border 47 of the end surface 46 of the objective 40 parallel to the optical axis 502. The geometric extrusion of the edge 47 of the end surface 46 of the lens 40 parallel to the optical axis 502 refers to a dimensional increase of the edge 47 of the end surface 46 of the lens 40 by parallel displacement in space parallel to the optical axis 502.In this way, the edge 47 of the end face 46 of the lens 40, representing a line or curve, is drawn along a direction parallel to the optical axis 502 such that the desired lateral surface 510 is obtained. The lateral surface 510 thus describes the surface formed by the geometric extrusion of the edge 47 of the end face 46 of the lens 40 parallel to the optical axis 502. This lateral surface 510 can also be understood as the enveloping surface of a cylindrical body which results from a geometric extrusion of the end face 46 along the optical axis 502 and which, depending on the course of the edge 47, can assume any cross-section, in particular in the form of a circle, an ellipse, or an oval. However, other cross-sectional shapes are possible.

[0072] This inventive design of the present device 10 thus makes it possible to use the installation space available on or outside the lateral surface 510 in the axial direction for the design of the membrane holder 80, without the usable working distance of the device 10 being advantageously restricted by mechanical elements which, according to the prior art, would be introduced between the end surface 46 of the objective 40 and the object 60.

[0073] Figure 2 shows a schematic representation of particularly preferred embodiments of the objective 40, which is intended for use in the device 10 according to the invention.

[0074] In Figure 2aFor this purpose, a cross-section through the lens 40 is shown, showing the end surface 46, the edge 47 of the end surface 46, an exit window 48, and a mount 49 of the lens 40. The part of the mount 49 of the lens 40 facing the object 60 forms a ridge line 500, which defines a contour enclosing the optical axis 502, which is formed by the points parallel to the optical axis 502 that protrude furthest in the direction of the object 60. Preferably, the ridge line 500 of the mount 49 of the lens 40 can be constructed as follows: First, cutting surfaces of the mount 49 are determined with a multiplicity of half-planes 503, which begin at the optical axis 502 and extend in the radial direction. The term "radial" is understood here to mean a direction that is perpendicular to the optical axis 502 and which Fig. 2b with the coordinate r or the local unit vector e r is referred to; the axial direction is parallel to the optical axis 502 and is defined by the coordinate z and the local unit vector easy The term "azimuthal", the corresponding parameter φ and the corresponding local unit vector e φ are used according to the known definitions of polar coordinates to denote a direction oriented locally perpendicular to the radial and azimuthal axes, where the direction results from the right-handedness of the coordinate system ( er , e φ , ez). Combinations of radial and azimuthal directions are also referred to as "lateral" directions. Each of the intersection surfaces of the mount 49 with a half-plane 503 has a contour 504, from which the ridge point 501 corresponding to the respective radial direction can be determined. For this purpose, assuming an object 60 with a flat surface 69 perpendicular to the optical axis 502, the point 501 of the contour 504 that is closest to the surface 69 of the object 60 is determined. A set of ridge points 501 corresponding to the various radial directions ultimately forms the ridge line 500. The ridge line 500 of the mount can also be used to define the term end surface 46: The end surface 46 includes at least the exit window 48 of the objective 40.In the case of a mount 49 adjoining this exit window 48, the end surface 46 additionally comprises the area of ​​the mount 49 enclosed by the ridge line 500 as well as all points outside the ridge line 500 which, in the case of a flat surface 69 of the object 60 aligned perpendicular to the optical axis 502, have a distance d' from the object which is preferably less than 5 mm, particularly preferably less than 1 mm, in particular less than 300 µm, greater than the maximum distance d of a point on the ridge line 500 from the surface 69 of the object 60. The end surface 46 of the objective 40 forms a simply connected area which is delimited by the edge 47. According to this definition, the points of the end surface 46 which are closest to the object 60 therefore do not necessarily lie on the ridge line 500 of the mount 49. A corresponding case is shown in . Figure 2d outlined. Figure 2dshows a schematic representation of a particularly preferred embodiment of the device 10, in which the objective 40 has a convexly curved exit window 48, while the exit window 48 in Fig. 2a to 2c is flat. In the case of the convexly curved exit window 48 of the lens 40, the points closest to the object 60 can lie on the exit window 48 itself. However, the above-described definition of the end surface 46 of the lens 48 remains unaffected by this configuration.

[0075] In Figure 2b A top view of the end face 46 of the lens 40 parallel to the optical axis 502 is shown. The ridge line 500, the end face 46, the edge 47, the exit window 48, and the mount 49 of the lens 40 are visible.

[0076] Figure 2c shows a schematic representation of a particularly preferred embodiment of the device 10, which the lens 40 from the Figures 2a and 2b Here, a working distance d between the exit surface 48 of the objective 40 and the surface of the object 60 is divided by the membrane 100 into a usable working distance d " between the side of the membrane 100 facing the object 60 and the object 60.

[0077] Figure 3 shows a schematic representation of an object in the form of a multi-chip module 61, which comprises several sub-objects 65, 66, 67, wherein the sub-objects 65, 66, 67 are applied to a common carrier plate 68, wherein, as in Figure 3 As shown, the support plate 68 can be placed on the specimen slide 50. Alternatively, the support plate 68 itself can form the specimen slide 50 (not shown).

[0078] Figure 4a schematic representation of a plurality of embodiments for the membrane holder 80 and the positioning elements 90. In addition, further embodiments according to the invention are conceivable, which include further possible combinations of membrane holders 80, membrane fastenings and positioning elements 90.

[0079] In the embodiment according to Figure 4a The membrane holder 80 is attached to the specimen slide 50. The membrane holder 80 can be movably mounted via an actuator 180 such that, in this embodiment, the membrane holder 80 can simultaneously serve as the positioning element 90, with which the partial region 120 of the membrane 100 penetrated by the light beam 140 can be axially moved. In an alternative embodiment, the membrane holder 80 can be attached to the specimen stage 51.

[0080] In the embodiment according to Figure 4bThe diaphragm holder 80 is attached to the lens stage 20. The diaphragm holder 80 can be movably mounted via an actuator 180 such that, in this embodiment, the diaphragm holder 80 can simultaneously serve as the positioning element 90 to axially move the portion 120 of the diaphragm 100 penetrated by the light beam 140.

[0081] In the embodiment according to Figure 4c), the membrane holder 80 is fastened to a further part of the lithography device 16. In this case, the membrane holder 80 can be movably mounted via an actuator 180 such that the membrane holder 80, in this embodiment, can simultaneously serve as the positioning element 90, with which the partial region 120 of the membrane 100 penetrated by the light beam 140 can be moved axially. In contrast to the objective 40, the further part of the lithography device 16 is not part of the optical beam path and is therefore subject to lower requirements in terms of precision and dynamic positioning than, for example, the objective, wherein the further part of the lithography device 16 used for fastening can absorb at least some of the forces acting on the membrane 100.

[0082] In the embodiment according to Figure 4d), the membrane holder 80 is attached to the lens table 20. The positioning elements 90 are also attached to the lens table 20 and thus allow the light-penetrating portion 120 of the membrane 100 to be moved axially synchronously with the movement of the lens table 20. The membrane holder 80 can preferably be attached to the lens table 20 by means of actuators 180 and / or one or more rigid fastening elements.

[0083] In the embodiment according to Figure 4e ), the membrane holder 80 is attached to the lens table 20 by means of one or more fastening elements 181. The positioning elements 90 are also attached to the lens table 20 by means of actuators 91, with the aid of which the partial area 120 of the membrane 100 penetrated by the light can be moved axially.

[0084] In the embodiment according to Figure 4f), the membrane holder 80 is attached to the lens stage 20. The positioning elements 90 are attached to the lens 40 and allow the light-penetrating portion 120 of the membrane 100 to be moved axially in synchronization with the movement of the lens 40. The membrane holder 80 can preferably be attached to the lens stage 20 by means of actuators 180 and / or one or more rigid fastening elements.

[0085] In the embodiment according to Figure 4g ), the membrane holder 80 is attached to the lens stage 20 by means of one or more fastening elements 181. The positioning elements 90 are attached to the lens 40 by means of additional actuators 91 and can move the light-penetrating portion 120 of the membrane 100 axially relative to the lens 40 via the actuators 91.

[0086] In the embodiment according to Figure 4h), the diaphragm holder 80 is attached to the lens stage 20 by means of one or more fastening elements 181. The lens 40 or a part of the lens 40 serves as the positioning element 90, which can axially move the portion 120 of the diaphragm 100 through which the light passes. Second contact points 96 between the diaphragm 100 and the lens 40 can be formed by the edge 47 of the end surface 46 of the lens 40, by the ridge line 500 of the end surface 46 of the lens 40, or by other components of the lens 40.

[0087] In the embodiment according to Figure 4i), the membrane holder 80 is fastened to the lens table 20 by means of one or more fastening elements 181. The lens 40 or a part of the lens 40 serves as the positioning element 90 for the axial movement of the partial area 120 of the membrane 100 penetrated by the light. If the lens 40 has a flat exit window 48 or one that is convexly curved in the direction of the object 60, the exit window 48 can, as well as Figure 2d can be seen, have a smaller distance from the object 60 than the mount 49 of the lens 40. In the case of a flexible membrane 100, this can cling to the exit window 48.

[0088] In the embodiment according to Figure 4j), the membrane holder 80 is attached to the slide 50 by means of one or more fastening elements 181. The positioning elements 90 are also attached to the slide 50 by means of their own actuators 91 and can axially move the portion 120 of the membrane 100 penetrated by the light via these actuators 91.

[0089] In the embodiment according to Figure 4k ), the membrane holder 80 is fastened to the slide 50 by means of one or more fastening elements 181. The positioning elements 90 are fastened to the objective stage 20 and allow the light-penetrated portion 120 of the membrane 100 to be moved axially in synchronism with the movement of the objective stage 20. Analogous to this embodiment, similar to the embodiment according to Figure 4e ) further designs are conceivable in which the positioning elements 90 are fastened to the lens table 20 with their own actuators 91.

[0090] In the embodiment according to Figure 4l), the membrane holder 80 is fastened to the slide 50 by means of one or more fastening elements 181. The positioning elements 90 are fastened to the objective 40 and allow the partial area 120 of the membrane 100 penetrated by the light to be moved axially synchronously with the movement of the objective 40. Analogous to this embodiment, similar to the embodiment according to Figure 4g ) further designs are conceivable in which the positioning elements 90 are attached to the lens 40 with dedicated actuators 91.

[0091] In the embodiment according to Figure 4m), the membrane holder 80 is attached to the slide 50 by means of one or more fastening elements 181. The objective 40 or a part of the objective 40 serves as the positioning element 90, which can axially move the partial area 120 of the membrane 100 through which the light passes. The contact points 96 between the membrane 100 and the objective 40 are formed by the edge 47 of the end surface 46 of the objective 40, by the ridge line 500 of the end surface 46 of the objective 40, or by another component of the objective 40. Analogous to the embodiment according to Figure 4i ), the exit window 48 can have a smaller distance from the object 60 than the mount 49 of the lens 40. In the case of a flexible membrane 100, this can also adapt to the exit window 48.

[0092] In the embodiment according to Figure 4n), the membrane holder 80 is attached to the specimen slide 50 by means of one or more fastening elements 181. The positioning elements 90 are attached to another part of the lithography device 16 by means of actuators 91 and can axially move the light-penetrating portion 120 of the membrane 100 with the actuators 91. Analogous to this embodiment, designs are also conceivable in which the membrane holder 80 can be attached to the lens stage 20, the specimen stage 51, or another part of the lithography device 16.

[0093] In the embodiment according to Figure 4o), the membrane holder 80 is attached to another part of the lithography device 16. The positioning elements 90 are attached to the lens stage 20 and allow the light-penetrating portion 120 of the membrane 100 to be moved axially synchronously with the movement of the lens stage 20. The membrane holder 80 can be attached by means of actuators 180 and / or one or more rigid fastening elements.

[0094] In the embodiment according to Figure 4p ), the membrane holder 80 is attached to another part of the lithography device 16. The positioning elements 90 have actuators 91, which are attached to the lens stage 20 and which enable the light-penetrating portion 120 of the membrane 100 to be moved axially relative to the lens 40.

[0095] In the embodiment according to Figure 4q), the membrane holder 80 is attached to another part of the lithography device 16. The positioning elements 90 are attached to the lens 40 and allow the light-penetrating portion 120 of the membrane 100 to be moved axially synchronously with the movement of the lens 40. The membrane holder 80 can preferably be attached by means of actuators 180 and / or one or more rigid fastening elements.

[0096] In the embodiment according to Figure 4r ), the membrane holder 80 is attached to another part of the lithography device 16. The positioning elements 90 have actuators 91, which are attached to the lens 40 and which allow the partial area 120 of the membrane 100 penetrated by the light to be moved axially relative to the lens 40. In the embodiment according to Figure 4s), the membrane holder 80 is attached to another part of the lithography device 16. The positioning elements 90 have actuators 91, which are attached to the object carrier 50 and enable the partial area 120 of the membrane 100 penetrated by the light to be moved axially.

[0097] In the embodiment according to Figure 4t ), the membrane holder 80 is attached to another part of the lithography device 16. The positioning elements 90 have actuators 91, which are attached to the same part of the lithography device 16 or to another part of the lithography device 17, and enable the partial area 120 of the membrane 100 penetrated by the light to be moved axially.

[0098] Figure 5shows a schematic representation of a device which comprises a plurality of devices 10, each of which can perform a selected function. In a first device 200, designed as a handling unit for immersion media, the immersion medium, in the form of a liquid photoresist 160, can be applied to the object 60 by means of a dispensing unit 35. The handling unit 200 for immersion media can further be configured to surround the object provided with the immersion liquid 160 with an object transport unit 55, preferably designed as a closed container, which has, for example, a membrane holder 80, a membrane 100, a specimen slide 50 and a fastening element 181, wherein alternatively or additionally a movable element or actuator 180 can be used to fasten the membrane holder 80 to the specimen slide 50. Transport of the object 60 orThe object transport unit 55 can be transferred from the handling unit 200 to the lithography unit 220 by means of a conveyor system 210 under normal ambient conditions. In the lithography unit 220, an additional indexing fluid 170 can optionally be applied between the membrane 100 and the lens 40 by means of a dispenser unit 30 before processing of the object 60 and / or optical characterization of the object 60 is carried out. In the case of lithographic processing, the object 60 or the object transport unit 55 can be transferred to a separate developer unit 230 in a further step with the aid of an additional conveyor system 210. In the developer unit 230, the object transport unit 55 can be opened again in order to remove unpolymerized parts of the photoresist from the object 60 by means of a rinsing unit 235.Other designs of the device comprising several devices 10 and their respective functions are possible.

[0099] The Figure 5The schematically illustrated device outlines a special case of an application of the device 10 according to the invention and a technical implementation of the method according to the invention, wherein the development steps downstream of the lithographic processing do not necessarily have to be included. Since a particular advantage of the membrane 100 used according to the invention lies in sealing off the volume of the immersion liquid 160 from the objective 40, the membrane 100 can simultaneously serve as protection for the immersion liquid 160 and the object 60. Thus, the membrane 100 can assume the function of a cover that can protect the object 60 and the immersion liquid in contact with it, preferably from contamination, from contact with oxygen or air humidity, or from unintentional exposure to short-wave ambient light.In particular, the membrane can also be electrically conductive and protect the components from electrostatic discharge (ESD). electrostatic discharge, ESD). To protect the object 60 and the immersion liquid 160 in contact with it, these can be placed in an object transport unit 55, which is designed to form a container that is as tightly sealed as possible by applying the membrane 100 and / or the membrane holder 80. Figure 5The schematically illustrated exemplary container comprises the specimen slide 50, the fastening element 181 integrated into or forming a side wall 52 of the specimen slide 50, the membrane holder 80, and the membrane 100, wherein the container is configured to receive the specimen 60 and the immersion liquid 160. A free space remaining in the container can optionally be filled with a protective gas to prevent contact of the immersion liquid 160 with oxygen or moisture present in the ambient atmosphere.By using the object transport unit 55 with protective function, the individual steps for the optical characterization or processing of the object 60 can be carried out in spatially separated functional units, wherein the object 60 can preferably be transferred together with the immersion liquid 160 between the functional units under normal ambient conditions, so that, as mentioned above, no special requirements with regard to cleanliness (e.g. clean room classes), exposure (e.g. so-called yellow light environment), atmospheric boundary conditions (e.g. regulated air humidity) and / or ESD protection are necessary in the spatial area traversed.The transfer of the object 60 protected by the membrane 100 between the various functional units is particularly advantageous with regard to the design of industrial manufacturing systems, since a specialized device can be used for each step and since it becomes possible, in particular, to separate the optical lithography processes from wet chemical processes.

[0100] Figure 6shows the results of a simulation of the imaging quality of the device 10 according to the invention. The device 10 comprises the objective lens 40 and the membrane 100, which separates two different immersion liquids, the liquid photoresist 160 and an immersion liquid 170. Within the scope of the simulation, a focusing of the light 140 was simulated on the object side using beam optics and displayed in a so-called "spot diagram." The spot diagram shows the position of various rays of a beam bundle in the focal plane of the objective lens 40. The area within the solid circle indicates the diffraction limit. In the simulation according to Figure 6a ), the refractive index 1.52 of both immersion liquids 160, 170 is well adapted to the objective 40, so that a nearly diffraction-limited focus is achieved. In the simulation according to Figure 6b) an intentional or unintentional change in the refractive index of the immersion liquid 160 to 1.53 occurs, for example due to aging or the use of a different substance with a slightly different composition. With the same position of the membrane 100, the focus has now become significantly larger and is no longer diffraction-limited. By moving the membrane 100 according to the simulation according to Figure 6c ), however, a diffraction-limited focus can be achieved again, and the change in the refractive index to 1.53 can thus be compensated. An optimal adjustment of the axial position of the membrane 100 thus allows for the compensation of aberrations that arise in lithography, for example, from slight variations in the refractive index of the photoresist used as the immersion medium.

[0101] Figure 7shows a schematic representation of another preferred embodiment of the device 10 according to the invention, which has a second membrane 105 attached to a second membrane holder 85. In addition to the immersion liquid 170 or the combination of the photoresist 160 and the immersion liquid 170, a further immersion liquid 175 is used here. The immersion liquids 170, 175 and the photoresist 160 can have different refractive indices, dispersion characteristics, and / or viscosities, thereby enabling additional degrees of freedom in compensating for aberrations. At least one of the membranes 100, 105 can be positioned in the axial direction by the at least one positioning element 90.

[0102] Figure 8shows a schematic representation of a further preferred embodiment of the device 10 according to the invention, in which forces for deforming and axially positioning the membrane 100 or the light-penetrating portion 120 of the membrane 100 are introduced by a positioning element 95 connected to the lens stage 20 or to the lens 40. Rollers or sliding surfaces at the contact points 96 between the positioning element 95 and the membrane 100 can ensure low friction during a lateral movement of the membrane 100 relative to the positioning elements 95.

[0103] Figure 9shows a schematic representation of a further preferred embodiment of the device 10 according to the invention, in which the membrane holder 80 is fastened to the lens table 20. The membrane holder 80 comprises an arrangement of rollers and / or sliding surfaces 85, which are attached to the lens table 20 by fastening elements 185 and which enable automatic removal and supply of further areas, in particular clean areas, of the membrane 110. The axial positioning of the light-penetrated partial area 120 of the membrane 100 can be achieved here via a mechanism in the membrane holder 80, for example by tensioning the rollers 85. Alternatively or additionally, positioning elements 90 can be used to adjust the axial position of the light-penetrated partial area 120 of the membrane.

[0104] Figure 10shows a schematic representation of a further preferred embodiment of the device 10 according to the invention, in which the membrane holder 80 is also fastened to the lens stage 20. This can preferably enable the use of different lenses 40, 41, 42, which can be exchanged, for example, by means of a revolver mechanism 45, without changing the position of the membrane 100. The positioning of the light-penetrated portion 120 of the membrane 100 can be achieved via movable elements 180 or actuators. An additional immersion liquid 170, optionally used between the membrane 100 and the respective lens 40, 41, or 42 in use, can be supplied after a change of the lens 40, 41, or 42 by a dispenser unit (not shown) integrated into the lithography unit 220.

[0105] Figure 11shows a schematic representation of an embodiment not forming part of the present invention, wherein the device 10 comprises a solid photoresist 161 covering the object 60. From Figure 11a ) shows that a first index liquid 160, which is adapted to the refractive index of the solid photoresist, together with the membrane 100 represents a defined optical interface, so that the light 140 can be coupled in via a dry lens. According to Figure 11b ) An additional immersion fluid 170 can be used between the membrane and the objective 40 to achieve a high NA and / or to compensate for aberrations due to a mismatch in the refractive index. Alternatively or additionally, the additional immersion fluid 170 can also have a viscosity different from that of the first index fluid 160.

[0106] Figure 12shows a schematic representation of another preferred embodiment of the device 10 according to the invention, in which the membrane 100 has a lateral structure 110. The lateral structures 110 of the membrane 100 can be used to optimize the wetting properties of the membrane 100 with respect to one or more immersion liquids 160, 170. In a further embodiment, one or more guide elements 115 can be used to limit the lateral spread of the immersion liquid 170.

[0107] Figure 13 shows a schematic representation of a preferred embodiment of an arrangement for a preferred membrane holder 300 and its positioning. The embodiment according to Figure 3 is based on the embodiment according to Figure 4b, wherein rigid fastening elements 181 are used here instead of the actuators 180. A membrane 100, which is preferably provided in the form of a thin film (not shown here), is placed over an inner ring 330. An outer ring 340 is pushed over the inner ring 330 to fix the membrane 100. The conical surfaces 345 in the inner ring 330 and on the outer ring 340 allow films of different thicknesses to be tensioned. The fixation of the outer ring 340 to the inner ring 330 is carried out here, for example, by means of clamping or by screwing in corresponding threaded holes 350. A further clamping device 310 can serve to fasten the membrane holder 300 to the lens stage 20. Fixed struts 320 can connect the clamping device 310 to the inner ring 330 of the membrane holder 300.The clamping device 310, which is open on one side, allows the holder 300 and the diaphragm 100 to be changed without having to remove the lens 40. The diaphragm holder 300 can be easily slid over the lens stage 20 to position the diaphragm 100 under the lens 40. The diaphragm holder 300 is formed by the rings 330, 340, while the struts 320 represent the rigid fastening elements 181. The axial positioning of the light-penetrating portion 120 of the diaphragm 100 is achieved here either solely by the diaphragm holder 300 or by the edge 47 or the ridge lines 500 of the lens 40.

[0108] The embodiment according to Figure 13can be expanded such that one of the fastening elements 181 or the lens stage 20 is provided with a sensor (not shown) with which any collisions of the membrane holder 300 or the membrane 100 with the object 60 or the object carrier 50 can be detected before the significantly more sensitive objective 40 is touched or damaged. An unwanted contact or collision between two components can be detected, for example, by a mechanical sensor or by an electrical sensor, which can preferably detect an electrical resistance between the two components and recognize a contact or collision by a reduction in the electrical resistance. For this purpose, it may be advisable to use a membrane 100 with sufficient electrical conductivity, which enables detection of a contact or collision between the membrane and another subcomponent of the device 10.

[0109] Figure 14 shows a schematic representation of a further embodiment that is not part of the present invention. Here, the object 60 is located on a slide 50, which can be covered with a membrane 100 that is stretched in a ring holder 420. The top view according to Figure 14a ) shows this version before assembly. In the top view according to Figure 14b ) the membrane 100 together with the object carrier 50 forms an object transport unit 55 designed as a closed container, which can protect the object 60 and the immersion liquid 160 previously applied to the object 60 from environmental influences. Figure 14c) shows a cross-section through the device 10 according to the invention, in which the at least one positioning element 90 can adjust an optimal working distance between the object 60, the objective 40, and the 100 membrane by elastic deformation of the membrane 100. In an alternative embodiment (not shown), the axial positioning of the light-penetrated portion 120 of the membrane 100 can also be achieved by the edge 47 or the ridge lines 500 of the objective 40, so that additional positioning elements 90 attached to the objective 40 can be dispensed with.

[0110] Based on the presentation in Figure 14An exemplary embodiment for the use of the method according to the invention in 3D lithography can be outlined. The object 60 is attached to the object carrier 50 according to step a). According to step b), a photoresist is applied to the object 60 as the immersion medium 160 for two-photon polymerization in a first functional unit. This is done manually or by means of a separate dispenser 35, which can additionally provide an inert gas atmosphere. After the application of the immersion liquid, the membrane 100, which is attached to a ring holder 420, is applied to the object carrier 50 according to step c) in such a way that the latter is preferably sealed airtight. This results in a process analogous to the exemplary embodiment according to Figure 5An object transport unit 55 is provided that can protect the object 60 from the ambient atmosphere. When using a membrane 100 that is not transparent in the UV range, the object 60 can also be transported through areas in which no pure yellow light illumination is provided. When using a membrane 100 that is electrically conductive, the object 60 can also be transported through areas that are not ESD-protected; the object transport unit 55 should be designed accordingly for this purpose. Subsequently, the object carrier 50 with the membrane 100 is transferred to a further functional unit designed as a lithography unit 220, in which the lithographic processing and / or optical characterization takes place.The object transport unit 55 remains closed in this functional unit, and a second immersion liquid 170 is optionally applied between the membrane 100 and the objective 40. The objective 40 is then brought closer to the membrane 100 according to step d). Since the ring holder 420 has a larger diameter than the objective 40, the positioning elements 90, which are attached to the objective 40 here, can bring the light-penetrating portion 120 of the membrane 100 into a favorable position between the object 60 and the objective 40 in synchronism with the axial movement of the objective 40. Once the desired axial position between the objective 40 and the object 60 has been achieved according to step e), the processing and / or characterization of the object 60 can now take place according to step f), wherein the processing can in particular comprise 3D structuring by means of 3D lithography.Substeps e) and f), which include positioning the membrane 100 and structuring the object 60, can be performed once or multiple times, for example, at different locations on the object 60 and thus on the membrane 100. After the 3D lithography according to step f), the object transport unit 55 remains closed and is transferred to another functional unit designed as a developer unit 230. In this functional unit, the membrane 100 can be removed with the ring holder 420, and the unpolymerized photoresist can be removed in a development process. Reference symbol list

[0111] 10Device 15Optical characterization or processing unit (lithography unit) 16, 17Further part of the lithography unit 20Objective stage 30Dispenser unit 40, 41, 42Objective 45Turret mechanism 46End surface 47Edge 48Exit window 49Mount 50Slide 51Slide stage 52Side wall of the slide 55Slide transport unit 60Slide 61Multi-chip module 65, 66, 67Sub-slide 68Carrier plate 69Surface of the slide 80, 85Membrane holder 81First contact point 85Rollers and / or sliding surfaces 90, 95Positioning element 91Actuator 96Second contact point 100, 105Membrane 110Lateral structures 115Guide element 120Light-penetrated part 130Part of the object 140(Laser) light 160, 170, 175Immersion medium (immersion liquid, photoresist) 161Solid photoresist 180Moving element (actuator) 181,185Fastening element 200Dispenser 210Conveyor system 220Lithography unit 230Developer unit 235Rinsing unit 300Membrane holder 310Clamping device 320Strut 330Inner ring 340Outer ring 345Conical surfaces 350Threaded hole 400Further preferred embodiment 420Ring holder 500Bridge line 501Bridge point 502Optical axis 503Half plane 504Contour 510Surface,

Claims

1. Apparatus (10) for optically processing an object (60), comprising - an object carrier (50) for receiving an object (60); - an optical processing unit (15), comprising at least one device for producing or receiving light (140) and an objective (40) for exposing the object (60) by using the light (140) or for capturing the light (140) from the object (60), wherein the objective (40) has an end face (46) facing the object carrier (50), wherein the end face (46) has an edge (47), wherein the objective (40) further defines an optical axis (502); - at least one membrane (100) introduced between the objective (40) and the object carrier (50), wherein the membrane (100) has a portion (120) configured for penetration by the light (140), wherein at least the portion (120) of the membrane (100) is movable in the axial direction with respect to the optical axis (502), - at least one membrane holder (80) for holding the at least one membrane (100), and - at least one immersion medium (160) which is at least introduced between the membrane (100) and the object carrier (50), wherein the membrane (100) and the membrane holder (80) are fastened at a point outside of the objective, and the membrane (100) is arranged at the membrane holder (80) in such a manner that first contact points (81) between the membrane (100) and the membrane holder (80) are located on or outside a lateral surface (510) which is formed by a geometric extrusion of the edge (47) of the objective (40) parallel to the optical axis (502), characterized in that the immersion medium (160) is present in the form of a liquid photoresist.

2. Apparatus (10) according to the preceding claim, wherein the membrane holder (80) is connected to an objective stage (20) that is formed to receive the objective (40), or to an object stage (51) that is formed to receive the object carrier (50), or to the object carrier (50), or to a further part (16, 17) of the optical processing unit (15).

3. Apparatus (10) according to either one of the preceding claims, wherein the objective (40) is configured in an exchangeable manner such that the objective (40) is able to be exchanged while the membrane holder (80) and the membrane (100) remain at the apparatus (10).

4. Apparatus (10) according to any one of the preceding claims, further comprising at least one positioning element (90, 91), wherein the positioning element (90, 91) is configured to move the membrane (100) in the axial direction with respect to the optical axis (502), wherein the positioning element (90, 91) is preferably arranged in such a manner that second contact points (96) between the membrane (100) and the positioning element (90, 91) are located on or outside of the lateral surface (510) which is formed by the geometric extrusion of the edge (47) of the objective (40).

5. Apparatus (10) according to the preceding claim, wherein the membrane holder (80) or a part of the objective (40) is simultaneously embodied as the positioning element (90, 91).

6. Apparatus (10) according to either of the two preceding claims, wherein the positioning element (90, 91) is connected to the objective stage (20) or to the object stage (51) or to the object carrier (50) or to the further part (16, 17) of the optical processing unit (15).

7. Apparatus (10) according to any one of the three preceding claims, wherein the membrane holder (80) and / or the positioning element (90, 91) comprise(s) fastening elements (185) which are configured to move the membrane (100) in the lateral direction between the objective (40) and the object (60) by manner of rollers and / or sliding surfaces (85).

8. Apparatus (10) according to any one of the preceding claims, wherein the membrane (100) or the membrane holder (105) is elastically or plastically deformable in such a manner that, as a result, the portion (120) of the membrane (100) is movable in the axial direction.

9. Apparatus (10) according to any one of the preceding claims, wherein a working distance d of no more than 5 mm has been configured between the end face (46) of the objective (40) and a surface of the object (60).

10. Apparatus (10) according to any one of the preceding claims, wherein the membrane (100) separates the immersion medium (160) and a further immersion medium (170) from one another, wherein the further immersion medium (170) has preferably been introduced between the membrane (100) and the objective (40).

11. Apparatus (10) according to the preceding claim, wherein a refractive index of the further immersion medium (170) differs from the refractive index of the immersion medium (160) and / or wherein a viscosity of the further immersion medium (170) differs from the viscosity of the immersion medium (160).

12. Apparatus (10) according to either of the two preceding claims, wherein the further immersion medium (170) is a liquid photoresist.

13. Apparatus (10) according to any one of the preceding claims, further comprising at least one sensor for detecting contact or a collision between two subcomponents of the apparatus (10).

14. Method for optical processing of an object (60) by using an apparatus (10) for optically processing an object (60), comprising the following steps: a) positioning at least one object (60) on an object carrier (50); b) applying an immersion medium (160) to at least part of the object (60); c) approaching a membrane (100) towards the part of the object (60) covered with the immersion medium (160), wherein the membrane (100) has a transparent portion (120) provided for light (140) to penetrate; d) positioning an objective (40), which defines an optical axis (502), relative to the part of the object (60) covered by the immersion medium (160); e) setting an axial position for the portion (120) of the membrane (100) with respect to the optical axis (502); and f) optically processing the object (60) by using the light (140), characterized in that the immersion medium (160) is present in the form of a liquid photoresist.

15. Method according to the preceding claim, wherein axial positioning of the portion (120) of the membrane (100) penetrated by the light (140) is implemented together with the positioning of the objective (40) in a synchronized movement.

16. Method according to either of the preceding method claims, wherein luminescence radiation excited by the light (140) in the immersion medium (160) is captured in order to set an axial position of the membrane (100).