Methods for post-processing and for handling of MEMS chips

Abstract

The invention relates to a method for post-processing of MEMS chips (100) and to a method for handling of MEMS chips (100). In the method for post-processing of MEMS chips (100) comprising MEMS structures (102) arranged on a carrier material (104) and having at least one projection region of projecting material protruding laterally beyond the region of the MEMS chip (100) provided with MEMS structures (102), at least one projection region (105) is removed by separation of the projecting material from the carrier material (104) of the MEMS chip. For handling of MEMS chips (100) without regions (105) projecting beyond the MEMS structures (102) arranged on a carrier material (104), in particular after post-processing according to the invention has been carried out, at least one lateral depression (108) is provided in the carrier material (104) and the MEMS chips (100) are handled by way of a tool (600) engaging in the lateral depression(s).

Description

Methods for post-processing and handling of MEMS chips

[0001] This application claims priority from German patent application 10 2023 203 941 . 9 , filed on April 27, 2023 . The content of this German patent application is incorporated by reference into the present application text.

[0002] The invention relates to a method for post-processing MEMS chips and a method for handling MEMS chips.

[0003] Microelectromechanical systems (MEMS) are small components that combine micromechanical structures and electronic elements in a single chip. MEMS chips can be manufactured in a similar way to microchips with integrated circuits. A MEMS chip generally comprises a carrier material on which the actual MEMS structures are arranged.

[0004] Typically, several MEMS chips are manufactured on a single wafer—again similar to microchips with integrated circuits. After the MEMS structures have been fabricated, the wafer is appropriately divided to create individual MEMS chips, which can then be reused and, for example, integrated into larger assemblies.

[0005] It is known to provide MEMS chips with a protective cover in order to protect the MEMS structures from environmental influences and mechanical damage, in particular during further handling after the production of the MEMS chips.

[0006] A known and preferred option in the prior art is to apply a wafer provided with suitable recesses to the wafer provided with the MEMS structures in such a way that the applied wafer rests against the carrier material of the MEMS chips in the areas between the groups of MEMS structures, each of which is assigned to a MEMS chip, and is firmly connected to it. When dividing the wafers connected to one another in this way to form individual MEMS chips, each MEMS chip is then provided with a protective cover that extends over the MEMS structures of the MEMS chip and protects them from environmental influences and mechanical damage.

[0007] For certain MEMS chips, particularly those with optical functions, a protective cover can be provided during production to simplify handling of the MEMS chips during integration into larger assemblies, e.g. the arrangement of one or more MEMS chips on a base plate substrate ("package substrate"). However, the protective cover must be removed regularly after integration has been completed in order to ensure proper optical function of the MEMS chip.

[0008] One possibility to remove a protective cover from MEMS chips when necessary is described, for example, in the conference paper "Temporary protective packaging for optical MEMS" by L. Bogaerts et al. (44th International Symposium on Microelectronics, October 9-13, 2011, Long Beach, CA, USA). A thermally decomposable adhesive is used to create the strong connection between the wafer that ultimately forms the actual MEMS chips with the MEMS structures arranged on it and the wafer with recesses that ultimately forms the protective cover. As soon as the protective cover is to be removed, the adhesive thermally decomposed, and the protective cover can be removed. The MEMS structures are then freely accessible again.

[0009] An example of optical MEMS chips are MEMS mirror arrays, in which a large number of small mirror elements are mounted so that they can each be moved individually relative to a common base. At least one actuator is provided for each mirror element, with which the mirror element can be adjusted along a predetermined degree of freedom. Depending on the application, mirror elements can in particular be pivoted about two axes running perpendicular to one another and parallel to the base, with sufficient actuators then being provided to be able to pivot the mirror element about these axes independently of one another. Sensors can also be provided for the individual mirror elements, with which the position of the mirror element relative to the base can be determined in order to be able to monitor the alignment of the mirrors.A particularly advantageous embodiment for the mirrors of a MEMS mirror array is described in DE 10 2015 204 874 A1.

[0010] Corresponding MEMS mirror arrays can be used in the production of microstructured components, such as integrated circuits, by photolithography.

[0011] For photolithography in the production of microstructured components, a projection exposure system is used, which comprises an illumination system and a projection system. The image of a mask (also called reticle) illuminated by the illumination system is projected by means of the projection system onto a substrate coated with a light-sensitive layer and arranged in the image plane of the projection system, for example a Silicon wafer, projected in a reduced size to transfer the mask pattern onto the light-sensitive coating of the substrate.

[0012] In illumination systems, particularly projection exposure systems designed for the EUV range, i.e., for exposure wavelengths from 5 nm to 30 nm, especially 13.5 nm, two facet mirrors are generally arranged in the beam path between the actual exposure radiation source and the mask to be illuminated. These facet mirrors enable radiation to be homogenized, essentially similar to the principle of a honeycomb condenser. The facet mirror closest to the exposure radiation source in the beam path is often a so-called field facet mirror, and the other is a so-called pupil facet mirror.

[0013] In order to be able to produce different intensity and / or angle of incidence distributions when illuminating the mask, the facets of at least one of the two facet mirrors—in particular those of the field facet mirror—can be formed from a plurality of electromechanically individually pivotable micromirrors or correspondingly configured MEMS chips, in particular MEMS mirror arrays. A corresponding disclosure is disclosed, for example, in WO 2012 / 130768 A2.

[0014] In particular, at an exposure wavelength of 13.5 nm, protective covers from MEMS chips must be removed according to current standards, since no protective cover is currently known that is sufficiently transmissive for radiation of this wavelength.

[0015] It has been shown that even after removing the Protective cover a frame around the actual MEMS Mirror arrays remain, which means that an optimal fill factor cannot be achieved when assembling a facet mirror from multiple MEMS mirror arrays. The "fill factor" is a measure of the integration density and represents the proportion of the reflection surface formed by the individual mirrors of the MEMS mirror arrays in relation to the total area of ​​the facet mirror (the so-called "fill factor").

[0016] The reduced integration density described above using facet mirrors as an example may also be relevant for other application areas and other types of MEMS chips.

[0017] The object of the present invention is therefore to create methods with which MEMS chips can be post-processed and further processed in such a way that, in particular, the disadvantage of reduced integration density known from the prior art no longer occurs or only occurs to a reduced extent.

[0018] This object is achieved by methods according to claims 1 and 13. Advantageous further developments are the subject of the dependent claims.

[0019] Accordingly, the invention relates to a method for post-processing MEMS chips comprising MEMS structures arranged on a carrier material with at least one overhang region of projecting material extending laterally beyond the region of the MEMS chip provided with MEMS structures, wherein at least one overhang region is removed by separating the projecting material from the carrier material of the MEMS chip.

[0020] Furthermore, the invention relates to a method for handling MEMS chips without areas projecting beyond the MEMS structures arranged on a carrier material, in particular after post-processing according to the invention, wherein at least one lateral recess is provided in the carrier material and the handling of the MEMS chips is carried out by engagement of a tool in the lateral recess(es).

[0021] The invention has recognized that material which protrudes laterally beyond the actual MEMS chip and has no effect on the actual functionality of the MEMS chip can have a negative effect on the integration density, particularly when a number of MEMS chips are to be arranged as closely packed as possible next to one another. The protrusion areas in question, which generally only contain non-functional material, act as unwanted spacers. Such protrusion areas are regularly present in MEMS chips which are provided with a protective cover during production, which is then removed again before or during integration, although the areas to which the protective cover was originally attached remain as a protrusion over the actual MEMS chip.

[0022] If, for example, a facet mirror for an illumination system of a projection exposure system is assembled from MEMS mirror arrays, where protective covers must generally be removed before or during integration - in particular the arrangement of the MEMS mirror arrays on a base plate substrate ("package substrate") - especially in the case of EUV illumination, distances between the individual MEMS mirror arrays arise due to the overhangs between the respective adjacent mirrors of two adjacent MEMS mirror arrays, which are larger than the distances between the mirrors of a of the MEMS mirror arrays among each other. This not only has a negative impact on the fill factor of a mirror constructed in this way, e.g. a facet mirror, but can also contribute to the creation of unwanted stray light, which can arise due to reflection or scattering of incoming radiation on the material in the protrusion areas. Protrusion areas also regularly lead to the individually controllable mirrors of a facet mirror comprising a large number of MEMS mirror arrays not actually being arranged in a uniform grid, which complicates the configuration and control of such a facet mirror. Similar disadvantages can also arise in other applications of MEMS chips.

[0023] Based on this finding, the present invention not only relates to methods with which existing protrusion areas of MEMS chips can be subsequently removed, but also to methods for handling MEMS chips which do not have any protrusion areas - either because they have been post-processed according to the invention or because they have been fundamentally manufactured without any protrusion areas.

[0024] According to the invention, existing but undesired protrusion areas are removed by separating the protruding material from the carrier material of the MEMS chip. The protruding material is thus detached from the carrier material of the MEMS chip and can then be easily removed.

[0025] To remove at least one protrusion area, a continuous gap can be created between the protrusion area and the carrier material of the MEMS chip. By creating the continuous gap, the material in the protrusion area is immediately and completely removed from the carrier material of the MEMS chips are separated, whereby a clean edge of the carrier material can usually be achieved.

[0026] It is also possible to remove at least one protrusion area by creating a predetermined breaking point between the protrusion area and the carrier material of the MEMS chip and then breaking open the predetermined breaking point. This offers the advantage that the material in the protrusion area can be severed in a controlled manner—namely, in particular, by the tool or similar device used to apply the force required for breaking open—and then immediately removed. The predetermined breaking point can be achieved by weakening the structure in this area, either by partially removing material or by weakening the material itself.If a predetermined breaking point to be created in a protruding area is too large or designed in such a way that a clean separation of the entire predetermined breaking point at once is not ensured, then the protruding area can also be divided into individual sections which are separated from one another by creating gaps and / or predetermined breaking points so that the sections can be detached individually by breaking open the respective predetermined breaking points between the protruding material and the carrier material.

[0027] It is possible to combine the two aforementioned alternatives for removing excess material. For example, in a MEMS chip with multiple excess material areas, part of each area can be removed by creating a continuous gap, while another part can be removed by creating a predetermined breaking point and then breaking it off.

[0028] A combination of both described measures for a single overhang area is also conceivable: Creating a predetermined breaking point to separate a Overhanging areas can involve creating a continuous gap in other areas and maintaining thin material bridges only in small areas, which then function as predetermined breaking points.

[0029] To prevent collisions between the material separated by creating a continuous gap or by breaking a suitably designed predetermined breaking point and the substrate material, or in particular the MEMS structures on the substrate, which could be damaged as a result, suitable measures can be taken. For example, the material can be connected in the overhang area with a tool or similar device before being separated from the substrate. This tool ensures that it remains connected even after separation, allowing it to be guided away from the substrate in a controlled manner.

[0030] To create a continuous gap and / or a predetermined breaking point, sacrificial material arranged in the corresponding area and differing at least from the protruding material and generally also from the carrier material can be removed. The sacrificial material can have been introduced during production of the MEMS chips, so that after its removal in the course of the method according to the invention only material bridges intended to create a predetermined breaking point remain or any structural connection between the carrier material and the material in the protruding area is eliminated, thus creating a continuous gap. However, it is also possible for sacrificial material to be introduced by suitable structuring processes only after production of the MEMS chips and possibly even after at least partial integration of the MEMS chip in a larger structural unit or an arrangement on a base plate substrate.

[0031] The sacrificial material can preferably be removed by an etching process. In this embodiment, the sacrificial material is preferably selected such that it can be removed residue-free by an etching process which, in particular, does not attack the carrier material and the MEMS structures of the MEMS chip. With knowledge of the materials used for the carrier material and the MEMS structures, a specialist can generally determine a suitable sacrificial material without further effort. In particular, if a directional etching process is to be used exclusively starting from the side of the carrier material facing away from the MEMS structures, it is also possible to protect the carrier material, at least in the area of ​​the MEMS chip, from damage during the etching process by providing suitable protective layers.

[0032] Furthermore, it can be provided that the MEMS chip is temporarily placed in an etching encapsulation for the removal of sacrificial material by means of an etching process, with which the volume to be filled with a suitable etching medium - in particular etching gas or etching liquid - is spatially delimited. The etching encapsulation preferably has an inlet and an outlet in order to be able to create a flow of etching medium in the volume delimited by the etching encapsulation, which can accelerate the etching process. If a protective cover is provided and also spans the MEMS chip at the time of the intended etching process, etching medium can be introduced into the area encapsulated by the protective cover and then removed again through channels already introduced into the protective cover in advance or openings created therein only briefly. In this case, the protective cover itself serves as the etching encapsulation.

[0033] As an alternative to the etching process, it is possible for the sacrificial material to be thermally decomposable. To remove the sacrificial material, the MEMS chip must then be heated to a temperature sufficient to decompose the sacrificial material, thus creating a continuous gap and / or a predetermined breaking point.

[0034] To create a continuous gap and / or a predetermined breaking point, residue-free removal of material can also be carried out, preferably by high-energy radiation. For this purpose, a focused particle beam, in particular a focused ion beam (FIB), preferably a focused gallium ion beam, can be used for ablation or gas-assisted etching, or a high-energy laser can be used for laser ablation.

[0035] To create a predetermined breaking point, it may also be necessary to specifically weaken the material in the area of ​​the predetermined breaking point, preferably by irradiation. The weakening can be achieved by changing the crystal structure, in particular by dissolving an existing mono- and / or polycrystalline structure into an amorphous structure. A laser beam or an ion beam, for example, can be used for this purpose. By appropriately focusing a laser beam, for which the material is fundamentally transparent, it is also possible to achieve an internal weakening of the material by dissolving the structure.

[0036] At least a temporary weakening of the material in the area of ​​a predetermined breaking point can also be achieved by reducing the density through local heating of the material. The necessary heat input can be achieved, for example, by a suitable laser beam.

[0037] What all of the above methods comprising irradiation have in common is that the beam required for the irradiation, in particular a laser or particle beam, in particular an ion beam, is usually strongly focused on a point or a line. However, such focused radiation has a numerical aperture - even if it is usually very small - which usually prevents the creation of a continuous gap and / or a predetermined breaking point directly at the edge of the carrier material of the MEMS chip, at least if the radiation can only be introduced perpendicularly - i.e. with an angle of incidence of 0° - to the carrier material. In this case, there is otherwise a risk that parts of the MEMS structures located at the edge of the MEMS chip will be hit and damaged by the widening of the incident beam.This risk can be reduced or completely avoided by selecting the appropriate angle of incidence—if adjustable. Alternatively, it is possible to use a radiation source that emits a collimated beam (i.e., a beam with exclusively parallel rays), with the beam being limited to the desired point of impact by a shadow mask. Depending on the extent of the beam, a suitable design of the shadow mask can also irradiate a linear point of impact simultaneously.

[0038] Once a predetermined breaking point has been created, it can be broken open by applying shear stress and / or tensile stress, whereby the protruding material is separated from the substrate and can be removed. Tensile stress on the predetermined breaking point occurs in particular when the protruding material is pulled away from the substrate in the plane of the MEMS chip substrate; Shear stress occurs in particular when an opposing force is applied to the carrier material and the protruding material perpendicular to the plane of the carrier material, regardless of the direction in which the force acts on the carrier material. The force can act directly on the carrier material or the protruding material. However, it is also possible to apply the force to the protruding material indirectly by acting on a protective cover that is still present at the time. Suitable push or pull tools can be used for this purpose, with pull tools preferably being connected to the component to be pulled by suction.

[0039] It is also possible to break a predetermined breaking point by changing the temperature and / or by introducing a temperature gradient. Particularly if the predetermined breaking point was created by weakening the material in that area, the predetermined breaking point can be broken by changing the temperature appropriately. It is only necessary to ensure that the temperature change in the area of ​​the predetermined breaking point, adjacent to it, and / or throughout the MEMS chip does not damage the carrier substrate or the MEMS structures.

[0040] As already mentioned on several occasions, at least one protrusion area to be removed can originally be designed to connect a protective cover for the MEMS chip. The protective cover can already be removed before the material in a protrusion area is separated; however, it is also possible for the protective cover to be removed at the same time as the protrusion area. In other words, the protective cover should still be connected to the material to be separated at the time a continuous gap is created or a predetermined breaking point is broken open. This often makes handling the separated material easier, and in particular, avoiding damage to the MEMS structure due to collision.

[0041] The MEMS chip from which at least one protrusion region is removed is preferably a MEMS mirror array, more preferably a MEMS mirror array for photolithography, particularly preferably a MEMS mirror array for EUV photolithography. The latter is characterized in particular by mirror surfaces that reflect radiation with a wavelength of 13.5 nm.

[0042] Following the post-processing process described above, provided all existing protrusion areas are removed, MEMS chips are produced that are limited exclusively to the area of ​​the MEMS structure and the substrate material supporting it. Of course, it is also possible to at least partially eliminate such protrusion areas during the production of MEMS chips, so that at least the number of protrusion areas to be removed using the process described above can be reduced—possibly even to zero.

[0043] For example, it is conceivable that when dividing a wafer on which MEMS structures for several MEMS chips are applied, at least some of the cutting lines are guided along the MEMS structures in such a way that after the corresponding cut has been carried out along this cutting line, no protrusion areas occur at least on some of the adjacent MEMS chips.

[0044] Alternatively, it is possible to start during the Production of the MEMS structures, the carrier material of the wafer is to be structured in such a way that a usually late In this step of the manufacturing process, continuous gaps can be introduced into the substrate material, which directly divide the substrate into the individual MEMS chips, thereby at least reducing the number of protrusion areas. It is even possible to produce MEMS chips without any protrusion areas in this way.

[0045] Irrespective of whether any still existing protrusion areas are removed using the method according to the invention as explained above, the resulting MEMS chip without any protrusion areas requires handling of MEMS chips that is different from the prior art. As already mentioned, corresponding protrusion areas are regularly required for attaching protective covers, which in turn are used in the prior art for marking purposes, in particular as an orientation and alignment aid for a MEMS chip. Furthermore, the protrusion areas are regularly used as points of attack for handling, e.g. using tools. With the elimination of the protrusion areas, in particular as a result of the method according to the invention, alternative methods for handling MEMS chips without areas that protrude beyond the MEMS structures arranged on a carrier material are required.

[0046] The invention therefore relates to a method for handling MEMS chips without regions projecting beyond the MEMS structures arranged on a carrier material. A corresponding MEMS chip can be created by post-processing according to the invention; however, this is not required.

[0047] The handling of corresponding "frameless" MEMS chips is carried out according to the invention by the intervention of a suitable tool in one or more lateral recesses in the Carrier material. "Lateral recesses" refer to recesses on the end faces of the carrier material. In particular, the side of the carrier material on which the MEMS structures are arranged, as well as its opposite side, are free of the aforementioned recesses intended for the insertion of handling tools.

[0048] It is preferred if at least two lateral depressions are provided on two mutually adjacent sides of the carrier material. The carrier material or the MEMS chip can then be gripped and handled in such a way that the remaining sides of the carrier material are free, which enables small distances to neighboring MEMS chips during integration, since no distances are required between the MEMS chips in which a handling tool would have to be guided between the MEMS chips. In order to avoid relative movements between the MEMS chip and the handling tool, in particular tilting, it may be preferable to provide three lateral depressions, two of which can be provided on the same side of the carrier material.

[0049] If recesses are provided only on two adjacent sides of the carrier material, but at least one side of the carrier material is free of recesses, the orientation of the MEMS structures of the MEMS chip relative to the carrier material can be read from the arrangement of the recesses, which can ensure the correct alignment of the MEMS chip during its integration.

[0050] Alternatively or additionally, markings can be arranged on the side of the carrier material. In addition to reference markings, which serve to ensure the correct orientation of the MEMS chips during integration, markings, e.g. in the form of a barcode, can also be arranged on the side of the carrier material. The markings can also be designed as depressions or groups of depressions.

[0051] Both the lateral recesses for tool engagement and the markings—if intended as recesses—can be added subsequently after the production of a MEMS chip. However, it is also possible to provide the carrier material with sacrificial material in the areas intended as recesses. In particular, the carrier material can already be provided with sacrificial material inside the wafer, which is then exposed and subsequently removed by splitting the wafer into individual MEMS chips.

[0052] As an alternative to handling a MEMS chip by reaching into lateral recesses in the carrier material, depending on the design of the MEMS chip, handling can also be achieved by directly engaging the MEMS structures. If the MEMS chip is, for example, a mirror array, a suction plate with a number of suction openings corresponding to the number and arrangement of the individual mirrors can create a firm connection between each individual mirror of the mirror array and the suction plate. This allows handling simply by engaging the MEMS structures, provided the MEMS structures are sufficiently resilient.

[0053] It is also possible to use electrostatic grippers, van der Waals grippers, vacuum grippers, Bernoulli grippers, and ultrasonic grippers to handle MEMS chips by attacking the MEMS structures. With Bernoulli grippers, the distance below which the gas flow is switched on must be selected to ensure sufficient gripping force and, in the case of a MEMS Mirror arrays as MEMS chips - the vibration excitations of the mirrors by the air flow remain within an acceptable range.

[0054] The invention will now be described by way of example using advantageous embodiments with reference to the accompanying drawings. They show: Figure 1: a schematic representation of a projection exposure system for photolithography comprising MEMS mirror arrays manufactured according to the invention; Figure 2a-e: a schematic representation of inventive methods for post-processing MEMS chips; Figure 3a-d : a schematic representation of possible design variants of the separation areas from Figure 2 ; Figure 4a, b : a schematic representation of the introduction of high-energy radiation into a separation area according to Figure 2 ; Figure 5a-c: a schematic representation of the separation of separation areas designed as predetermined breaking points from Figure 2; Figure 6a-c : a schematic representation of tools for separating predetermined breaking points according to Figure 5 ; Figure 7a, b : a schematic representation for removing sacrificial material from separation areas according to Figure 2 ; Figure 8a-c: a schematic diagram for the production of MEMS chips with and without protrusion areas; and Figure 9a, b: a schematic diagram for handling MEMS chips without protrusion areas.

[0055] Figure 1 shows a schematic meridional section of a projection exposure system 1 for photolithography. The projection exposure system 1 comprises an illumination system 10 and a projection system 20.

[0056] With the help of the illumination system 10, an object field 11 in an object plane or reticle plane 12 is illuminated. The illumination system 10 comprises an exposure radiation source 13 which, in the illustrated embodiment, emits illumination radiation at least comprising useful light in the EUV range, i.e. in particular with a wavelength between 5 nm and 30 nm. The exposure radiation source 13 can be a plasma source, for example an LPP source (laser produced plasma, plasma generated with the aid of a laser) or a DPP source (gas discharge produced plasma, plasma generated by means of gas discharge). It can also be a synchrotron-based radiation source. The exposure radiation source 13 can also be a free-electron laser (FEL).

[0057] The illumination radiation emanating from the exposure radiation source 13 is first bundled in a collector 14. The collector 14 can be a collector with one or more ellipsoidal and / or hyperboloidal reflection surfaces. The at least one reflection surface of the collector 14 can be used in grazing incidence (Gl), i.e., with angles of incidence greater than 45°, or in normal incidence (NI), i.e., with The collector 14 can be structured and / or coated to optimize its reflectivity for the useful radiation and to suppress stray light.

[0058] After the collector 14, the illumination radiation propagates through an intermediate focus in an intermediate focal plane 15. If the illumination system 10 is constructed in a modular design, the intermediate focal plane 15 can in principle be used for the - also structural - separation of the illumination system 10 into a radiation source module, comprising the exposure radiation source 13 and the collector 14, and the illumination optics 16 described below. With such a separation, the radiation source module and illumination optics 16 then together form a modular illumination system 10.

[0059] The illumination optics 16 comprises a deflecting mirror 17. The deflecting mirror 17 can be a flat deflecting mirror or, alternatively, a mirror with a beam-influencing effect beyond the pure deflection effect. Alternatively or additionally, the deflecting mirror 17 can be designed as a spectral filter that separates a useful light wavelength of the illumination radiation from stray light of a different wavelength.

[0060] The deflecting mirror 17 deflects the radiation originating from the exposure radiation source 13 onto a first facet mirror 18. If the first facet mirror 18 is arranged—as in the present case—in a plane of the illumination optics 16 that is optically conjugated to the reticle plane 12 as a field plane, it is also referred to as a field facet mirror.

[0061] The first facet mirror 18 comprises a plurality of micromirrors 18', each of which can be individually pivoted about two mutually perpendicular axes, for the controllable formation of facets, each of which is preferably equipped with an orientation sensor (not shown) for determining the orientation of the micromirror 18'. The first facet mirror 18 is thus a microelectromechanical system (MEMS system), as described, for example, in DE 10 2008 009 600 A1.

[0062] In the beam path of the illumination optics 16, a second facet mirror 19 is arranged downstream of the first facet mirror 18, resulting in a double-faceted system, the basic principle of which is also referred to as a honeycomb condenser (fly's eye integrator). If the second facet mirror 19 - as in the illustrated embodiment - is arranged in a pupil plane of the illumination optics 16, it is also referred to as a pupil facet mirror. However, the second facet mirror 19 can also be arranged at a distance from a pupil plane of the illumination optics 16, whereby the combination of the first and the second facet mirror 18, 19 results in a specular reflector, as is the case, for example. in US 2006 / 0132747 A1, EP 1 614 008 B1 and US 6,573,978.

[0063] The second facet mirror 19 does not have to be constructed from pivotable micromirrors, but can rather comprise individual facets formed from one or a manageable number of mirrors that are significantly larger than micromirrors, which are either fixed or can only be tilted between two defined end positions. However, as shown, it is also possible for the second facet mirror 19 to be a microelectromechanical system with a plurality of individually pivotable mirrors that can each be tilted by two perpendicular to provide micromirrors 19' which can be pivoted about axes extending relative to one another, each preferably comprising an orientation sensor.

[0064] With the aid of the second facet mirror 19, the individual facets of the first facet mirror 18 are imaged into the object field 11, whereby this usually only involves an approximate image. The second facet mirror 19 can be the last beam-forming mirror or actually the last mirror for the illumination radiation in the beam path before the object field 11.

[0065] Each facet of the second facet mirror 19 is assigned to exactly one of the facets of the first facet mirror 18 to form an illumination channel for illuminating the object field 11. This can, in particular, result in illumination according to the Köhler principle.

[0066] The facets of the first facet mirror 18 are each imaged by an associated facet of the second facet mirror 19, superimposed on one another, to illuminate the object field 11. The illumination of the object field 11 is thereby as homogeneous as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0067] By selecting the illumination channels ultimately used, which is easily possible by suitable adjustment of the micromirrors 18' of the first facet mirror 18, the intensity distribution in the entrance pupil of the projection system 20 described below can also be adjusted. This intensity distribution is also referred to as illumination setting. In this case, It may be advantageous not to arrange the second facet mirror 19 exactly in a plane that is optically conjugated to a pupil plane of the projection system 20. In particular, the pupil facet mirror 19 can be arranged tilted relative to a pupil plane of the projection system 20, as described, for example, in DE 10 2017 220 586 A1.

[0068] In the arrangement of the components of the illumination optics 16 shown in Figure 1, the second facet mirror 19 is arranged in a surface conjugated to the entrance pupil of the projection system 20. Deflecting mirror 17 and the two facet mirrors 18, 19 are tilted both relative to the object plane 12 and relative to each other.

[0069] In an alternative, not shown embodiment of the illumination optics 16, a transmission optics comprising one or more mirrors can be provided in the beam path between the second facet mirror 19 and the object field 11. The transmission optics can in particular comprise one or two mirrors for normal incidence (NI mirrors, normal incidence mirrors) and / or one or two mirrors for grazing incidence (GI mirrors, gracing incidence mirrors). With an additional transmission optics, in particular, different positions of the entrance pupil for the tangential and for the sagittal beam path of the projection system 20 described below can be taken into account.

[0070] Alternatively, it is possible to dispense with the deflection mirror 17 shown in Figure 1, for which purpose the facet mirrors 18, 19 are then to be suitably arranged opposite the radiation source 13 and the collector 14.

[0071] With the help of the projection system 20, the object field 11 in the reticle plane 12 is transferred to the image field 21 in the image plane 22.

[0072] For this purpose, the projection system 20 comprises a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1.

[0073] In the example shown in Figure 1, the projection system 20 comprises six mirrors Mx to M6. Alternatives with four, eight, ten, twelve, or a different number of mirrors Mi are also possible. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation, thus making the projection system 20 shown a doubly obscured optics. The projection system 20 has an image-side numerical aperture that is greater than 0.3 and can also be greater than 0.6, for example, 0.7 or 0.75.

[0074] The reflection surfaces of the mirrors M ± can be designed as freeform surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors M ± but can also be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflection surface shape. The mirrors Mi, like the mirrors of the illumination optics 16, can have highly reflective coatings for the illumination radiation. These reflective coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0075] The projection system 20 has a large object-image offset in the y-direction between a y-coordinate of a center of the object field 11 and a y-coordinate of the center of the image field 21. This object-image offset in the y- Direction can be approximately as large as a z-distance between the object plane 12 and the image plane 22.

[0076] The projection system 20 can in particular be anamorphic, ie it has in particular different image scales ß x , ß y in the x- and y-direction. The two magnifications ß x , ß y of the projection system 20 are preferably (ß x , ß y ) = (+ / - 0.25, / + - 0.125). A magnification ß of 0.25 corresponds to a reduction in the ratio 4:1, while a magnification ß of 0.125 results in a reduction in the ratio 8:1. A positive sign for the magnification ß means an image without image inversion, a negative sign an image with image inversion.

[0077] Other magnifications are also possible, including identical and absolutely identical magnifications ß x , ß y in x and y directions are possible.

[0078] The number of intermediate image planes in the x- and y-directions in the beam path between the object field 11 and the image field 21 can be the same or different, depending on the design of the projection system 20. Examples of projection systems 20 with different numbers of such intermediate images in the x- and y-directions are known from US 2018 / 0074303 A1.

[0079] The projection system 20 can, in particular, have a homocentric entrance pupil. This can be accessible. But it can also be inaccessible.

[0080] A reticle 30 (also called a mask) arranged in the object field 11 is illuminated by the illumination system 10 and transferred to the image plane 21 by the projection system 20. The reticle 30 is held by a reticle holder 31. The Reticle holder 31 can be displaced, in particular, in a scanning direction via a reticle displacement drive 32. In the illustrated embodiment, the scanning direction runs in the y-direction.

[0081] A structure on the reticle 30 is imaged onto a light-sensitive layer of a wafer 35 arranged in the region of the image field 21 in the image plane 22. The wafer 35 is held by a wafer holder 36. The wafer holder 36 can be displaced, in particular along the y-direction, via a wafer displacement drive 37. The displacement of the reticle 30, on the one hand, via the reticle displacement drive 32, and the displacement of the wafer 35, on the other hand, via the wafer displacement drive 37, can be synchronized with one another.

[0082] The projection exposure system 1 shown in Figure 1 or its illumination system 10, the above description of which essentially reflects known prior art, is characterized in that the first and / or second facet mirrors 18, 19 comprise one or more MEMS chips 100 post-processed according to the invention (cf., among others, Figure 2), namely, in particular, MEMS mirror arrays 101. Each of the MEMS chips 100 has a plurality of individual mirrors 103, which can be adjusted independently by two degrees of rotational freedom each, as parts of a MEMS structure 102 and which are arranged in a two-dimensional grid. Each of the facet mirrors 18, 19 can be formed by a single one or more MEMS chips 100 or MEMS mirror arrays 101 arranged next to one another.

[0083] Corresponding MEMS mirror arrays 101 are known to be manufactured together with a plurality of other MEMS mirror arrays 100 or other MEMS chips 100 on a common wafer and to be connected to further, with suitable recesses provided wafer is covered, so that when the wafer is subsequently divided into individual MEMS mirror arrays 101 or MEMS chips 100, a protective cover 106 is retained for each individual MEMS mirror array 100.

[0084] Figure 2a shows two examples of MEMS chips 100 and MEMS mirror arrays 101 schematically in a sectional view, as they generally appear after a wafer has been divided. In the MEMS chips 100 and MEMS mirror arrays 101, the actual MEMS structure 102—that is, the individual mirrors 103 and all components required for systematic pivoting—is arranged on a carrier material 104.

[0085] The carrier material 104 extends laterally beyond the region in which the MEMS structures 102 are arranged, thus forming a protruding region 105 of protruding material. These protruding regions 105 serve to connect the protective cover 106, which extends over the MEMS structures 102. The protective cover 106 can, for example, be firmly connected to the protruding regions 105 using an adhesive. Other joining methods, such as an anodic bonding method, are also possible for connecting the protective cover 106 to the protruding regions 105.

[0086] In the embodiment shown on the left in Figure 2a, a separation region 200 is already formed between the carrier material 104 in the area provided with MEMS structures 102 and the overhang regions 105, which will be explained in more detail below in connection with Figure 3. In the embodiment shown on the right in Figure 2b, a corresponding separation region 200 is not (yet) provided.

[0087] Also shown in Figure 2a is a base plate substrate 150 (“package substrate”) on which the MEMS chip 100 or the MEMS mirror array 101 is to be or is arranged. The base plate substrate 150 can be adapted in its extent to the extent of the area of ​​the carrier material 104 provided with MEMS structures 102. However, it is also possible for the base plate substrate 150 to be significantly larger than the area in question, which is indicated in Figure 2 by the parts of the base plate substrate 150 shown in dashed lines.

[0088] Although shown in principle in Figure 2, the method according to the invention can also be carried out without providing a base plate substrate 150, i.e., solely with the actual MEMS chip 100. In this case, the step shown in Figure 2b is to be skipped, and the base plate substrate 150 is to be neglected in the subsequent figures.

[0089] Figure 2b shows that the MEMS chip 100 or the MEMS mirror array 101 is firmly connected to the base plate substrate 150. If the base plate substrate 150 extends beyond the area of ​​the carrier material 104 provided with MEMS structures 102, the overhang areas 105 and, if applicable, the separation area 200 should not be connected to the base plate substrate 150 if possible.

[0090] In a next step, the protective cover 106 can optionally be removed, which is why it is only shown in dashed lines in Figure 2c. To remove the protective cover 106, the adhesive bond between the protective cover 106 and the protruding area 105 can be released. If the adhesive used is a thermally decomposable adhesive, the temperature can, for example, be increased at least locally. Other separation methods are of course also possible. Whether the protective cover 106 actually has to be removed or not depends crucially on the design of the already existing separation region 200 (Figure 2c, left) or of the separation region 200 still to be created (Figure 2c, right). In this case, it is particularly relevant whether the separation region 200 has to be accessible from the areas covered by the protective cover 106, which will generally be the case in particular if the arrangement has already been made on a base plate substrate 150; if there is (as yet) no base plate substrate 150, the separation region 200 is accessible from the side of the carrier material 104 facing away from the MEMS structures 102, so that the protective cover 106 may not have to be removed in the step shown in Figure 2c.

[0091] If the separation region 200 has not yet been formed (Figure 2c, right), this must be done in the next step (Figure 2d, right). Possible configurations for the separation region 200 are described in more detail below in connection with Figure 3.

[0092] Finally, the protruding portions 105 are severed and removed at the separation portions 200 (Figure 2e). If the protective cover 106 was still firmly connected to the protruding portions 105, the protruding portions 105 and the protective cover 106 can be removed as a unit. Some possible methods for actually removing the protruding portions 105 and the protective cover 106 are discussed in connection with Figures 5 to 7.

[0093] If the MEMS chip 100 has not already been installed on a Base plate substrate 150 have been arranged, the MEMS chip 100 at the latest at this time on a Base plate substrate, which is further explained in connection with Figure 9.

[0094] Figure 3 shows various embodiments of separation regions 200 and methods for separating excess material in excess regions 105.

[0095] In Figure 3a, the separation area 200 in the initial state (Figure 3a, left) is not specially designed. Rather, the carrier material 104 extends over the separation area 200 into the overhang area 105. To separate the overhang area 105, a continuous column 201 between the overhang region 105 and the carrier material 104 of the MEMS chip 100 by removing the material present there in the initial state without leaving any residue (Figure 3a, right). The removal can be achieved, in particular, by high-energy radiation, such as ion radiation or laser radiation. Possible embodiments for this are described below with reference to Figure 4.

[0096] The high-energy radiation can be applied to the separation region 200 from the side of the carrier material 104 provided with MEMS structures 102 and / or the opposite side. Once the continuous gap 201 is completed, the overhang region 105 and any protective cover 106 still connected thereto are immediately separated from the carrier material 104 and can be removed directly.

[0097] Figure 3b shows an alternative procedure for creating a continuous gap 201 between the carrier material 104 and the overhanging area 105. Here, in the initial state (Figure 3b, left), a sacrificial material 202 is provided in the separation area 200, which is separated from both the carrier material 104 and the overhanging material in the Projection region 105 is distinguished. The sacrificial material 202 can be introduced into the carrier material 104, in particular during the production of the MEMS structures 102, or can have already been introduced at this time.

[0098] To create a continuous gap 201, only the sacrificial material 202 needs to be removed. The sacrificial material 202 can be removed, in particular, by an etching process, wherein a suitable selection of sacrificial material 202 and etching agents can ensure that neither the carrier material nor the MEMS structures 102 are damaged. Alternatively, the sacrificial material 202 can be thermally decomposable, and the continuous gap 201 can be created by sufficiently heating at least the sacrificial material 202. Of course, it is also possible to remove the sacrificial material 202 by suitable high-energy radiation.

[0099] After complete removal of the sacrificial material 202, the continuous gap 201 is created, whereby the overhanging region 105 and any protective cover 106 still connected thereto are directly separated from the carrier material 104. The overhanging region 105 and / or the protective cover 106 can then be removed immediately.

[0100] In the embodiment according to Figure 3c, no continuous gap 201 (cf. Figures 3a, b) is created, but rather a debit entry point 203, in which the material in the separation area 200 is reduced to a thin and easily breakable material bridge 204. The position and other configuration of the material bridge 204 within the separation area 200 can be chosen as desired, wherein an edge position relative to the carrier material 104, as shown by way of example in Figure 3c, center, is advantageous. is because it requires only one-sided machining of the MEMS chip 100 to create it.

[0101] To create the predetermined breaking point 203, the processes described in connection with Figures 3a and 3b can be used, namely the residue-free removal of material in the separation region 200 by high-energy radiation or by removing sacrificial material 202 previously introduced into this region. For an explanation of these processes, reference is made to the above explanations. The only essential point is that the material bridge 204 remains in the embodiment according to Figure 3c.

[0102] After creating the predetermined breaking point 203, the projecting area 105 and any protective cover 106 still connected thereto can be detached from the carrier material 104 by breaking the predetermined breaking point 203 and then removed. Variants for breaking the predetermined breaking point 203 will be explained with reference to Figures 5 to 7.

[0103] Figure 3d shows a further alternative for creating a predetermined breaking point 203. Starting from a separation region 200, over which the carrier material 104 extends into the overhang region 105 (Figure 3d, left), material in the region of the predetermined breaking point 203 to be created is specifically weakened. This is shown in Figure 3d, middle, by weakened regions 205. For example, by suitable radiation, the crystal structure of the carrier material 104 in the weakened regions 205 can be dissolved, i.e., transformed from a mono- and / or polycrystalline structure to an amorphous structure. Local heating can also lead to a reduction in the density in the weakened regions 205 and thus to a weakening of the material.

[0104] After weakening has taken place, the predetermined breaking point 203 thus created can be broken open, whereby the projecting area 105 and any protective cap 106 still connected thereto are separated from the carrier material 104 and can be removed.

[0105] In all processes described above with reference to Figure 3, in which high-energy radiation is used to create a continuous gap 201 or a predetermined breaking point 203, it should be noted that corresponding radiation 300 (cf. Figure 4a), even if it is highly focused, has a numerical aperture - albeit a generally very small one - which can make irradiation more difficult, in particular on the side of the carrier material 104 with the MEMS structure 102 arranged thereon. Due to the numerical aperture - at least when the angle of incidence for the radiation is set to 0 °, which is regularly the case - it is hardly possible to create a continuous gap 201 or a predetermined breaking point 203 immediately adjacent to the area of ​​the carrier material 104 actually provided with the MEMS structure 102 when irradiating the side of the carrier material 104 with the MEMS structure 102 arranged thereon.If such an approach were to be taken, the MEMS structure 102 would almost inevitably be hit by the focused radiation 300 and be damaged.

[0106] Alternatively, as outlined in Figure 4b, it is possible to use a collimated beam 301 (i.e., a beam with exclusively parallel rays), wherein the limitation of the beam 301 to the separation region 200 is achieved by a suitable shadow mask 302. In this case, the radiation incident in the separation region 200 has an angle of incidence of 0°, so that even when irradiated on the MEMS structures 102 provided side of the carrier material 104, the residue-free removal of material immediately adjacent to the area of ​​the carrier material 104 provided with MEMS structures 102 is possible.

[0107] If a predetermined breaking point 203 is created in the separation area 200 (see Figures 3c, d), three possible ways of breaking open such a predetermined breaking point 203 are outlined in Figure 5. In principle, the manner in which the predetermined breaking point 203 is created or designed is arbitrary.

[0108] According to Figure 5a, the predetermined breaking point 203 is separated by introducing a shear stress into the predetermined breaking point 203. Such a shear stress can be achieved by applying opposing forces to the carrier material 104 and the overhang region 105. This is indicated by the arrows 90 in Figure 5a, although the orientation of the arrows 90 can also be reversed.

[0109] Alternatively, as outlined in Figure 5a, a predetermined breaking point 203 can also be broken open by applying sufficient tensile stress thereto, which is indicated by the arrows 91.

[0110] When breaking the predetermined breaking point 203 according to Figure 5a, which is particularly relevant for the design variants of predetermined breaking points 203 in which the material in the separation region 200 is partially weakened (cf. Figure 3d), a temperature or a temperature gradient is introduced into the predetermined breaking point 203 (indicated by the heating element 92, although cooling may also be provided). Different thermal expansion of weakened regions 205 compared to the unchanged material can, for example, cause the predetermined breaking point to break open.

[0111] Figure 6 shows different variants or tools 400 shows how the shear stress already mentioned in Figure 5a can be introduced into a predetermined breaking point 203 .

[0112] In Figure 6a, it is assumed that the protective cover 106 is still firmly connected to the overhanging areas 105, which in turn - unlike the carrier material 104 in the area with MEMS structures 102 - is not connected to the base substrate plate 150.

[0113] In this case, the tool 400 for breaking open the predetermined breaking point 203 is a suction punch 401, which can be firmly connected to the protective cover 106 by creating a vacuum between the suction punch 401 and the latter. By pulling on the suction punch 401 in the direction away from the base substrate plate 150 while simultaneously fixing the latter, a shear stress is generated in the predetermined breaking point 203, which can result in its breaking open, whereupon the protective cover 106 and the protruding regions 105 firmly connected thereto can be removed from the MEMS chip 100 by the suction punch 401. As an alternative to a suction punch 401, a comparable tool 400 can also be firmly connected to the protective cover 106 by adhesive.

[0114] The tool 400 in Figure 6b is particularly suitable for use with MEMS chips 100 that are arranged on a base substrate plate 150 that does not extend beyond the area of ​​the carrier material 104 provided with MEMS structures 102. The tool 400 comprises movable jaws 402 that, as shown in Figure 6b, are positioned adjacent to the base substrate plate 150. By vertically moving the jaws 402, with the base substrate plate 150 held in place, the predetermined breaking points 203, via which the protrusion areas 105 lying against a jaw 402 can be the carrier material 104 are broken open, and the separated material can be removed. It is irrelevant whether a protective cover 106 is connected to the protruding areas 105 or not at the time of breaking open.

[0115] In Figure 6c, the tool 400 from Figure 6b is used again, but here the jaws 402 are positioned over the protrusion areas 105 in such a way that a vertical movement of the jaws 402 in the direction of the base substrate plate 150 breaks off the protrusion areas 105 in the direction of the base substrate plate 150 at the respective predetermined breaking point 203. The advantage of this embodiment is that there is no risk of collision between the severed material and the MEMS structure 102. However, with this embodiment, any protective cover 106 that may be present must be removed before the first predetermined breaking point 203 is broken open.

[0116] If a sacrificial material 202 is provided in the separation region 200 (cf. Figure 3b, c), which must be removed to create a continuous gap 201 or a predetermined breaking point 203, this can be done, for example, by an etching process with an etching medium, for example with etching gas.

[0117] In order to keep the volume to be supplied with etching medium as small as possible and to protect areas remote from the MEMS chip 100 from etching medium, inlet and outlet channels 107 can be introduced into a protective cover 106 still present at this time or can be introduced if necessary, through which an etching medium suitable for dissolving the sacrificial material 202 in the separation region 200 can be introduced and used etching medium etc. can also be removed again (cf. Figure 7a). The detachment of protective cover 106 and associated Overhang areas 105 after the sacrificial material 202 has been removed - regardless of whether this creates a continuous gap 201 or a predetermined breaking point 203 - can then be carried out, for example, as shown in Figure 6a.

[0118] Figure 7b shows a variant in which the MEMS chip 100, with or without protective cover 106 (therefore only shown in dashed lines), is accommodated in a separate etching chamber 450 which encloses the MEMS chip 100 together with any base substrate plate 150 that may be present or - as shown - lies sealingly against the base substrate plate 150, and through whose inlets and outlets 451 etching medium is introduced. In particular, this also makes it possible to remove sacrificial material 202 in the separation regions 200 that is accessible exclusively from the side facing away from the MEMS structures 102. For the final removal of the projecting regions 105 and / or the protective cover 106, possibly including breaking open a created predetermined breaking point, reference is made to the above explanations.

[0119] Even if existing protrusion areas 105 can be removed by the method for post-processing MEMS chips 100 described above, protrusion areas 105 can already be reduced or even completely avoided during the production of corresponding MEMS chips 100, whereby the effort for corresponding post-processing can also be reduced or completely eliminated.

[0120] Figure 8a shows a typical manufacturing process for MEMS chips 100: Several groups of MEMS structures 102 are created on a wafer 500, each group later forming the MEMS structures 102 of a single MEMS chip 100 (Figure 8a, left). Between the groups of MEMS structures 102, a free space 501 is provided, which - as can be seen from the known from the prior art - for example, it can be used to connect a wafer with recesses (not shown) to the wafer 500 shown, so that after the wafer 500 has been separated, protective covers 106 for the MEMS chips 100 can be created in the center through the free spaces. The situation after such a division of the wafer 500 is shown in Figure 8a, right. After the wafer 500 has been separated, each MEMS chip 100 has a circumferential overhang region 105, to which in particular individual protective covers 106 can be attached (cf. Figure 2).

[0121] In order to facilitate the removal of the protruding regions 105, it may be provided, when dividing the wafer 500 or at a later time, to subdivide the protruding regions 105 into individual sections by creating gaps or weakened regions 502, which in principle can also be removed individually.

[0122] In particular, if no protective cover 106 is required during further handling of the MEMS chips 100, the MEMS structures 102 can be arranged in pairs on the wafer 500, directly adjacent to one another in one direction (Figure 8b, left). After dividing the wafer 500, individual MEMS chips 100 are then produced, in which the protrusion regions 105 are no longer present all the way around (cf. Figure 8a, right), but only on two of the four sides of each MEMS chip 100 (Figure 8b, right). The effort required for post-processing, namely for removing the remaining protrusion regions 105, is correspondingly reduced. Here, too, the protrusion regions 105 can be suitably divided into sections that can be removed individually.

[0123] Alternatively, it is of course also possible to arrange the MEMS structures 102 entirely without free space 501 (cf. Figures 8a, b) on the wafer 500 (cf. Figure 8c, left), so that after dividing the wafer 500, MEMS chips 100 are immediately produced without any overhang areas 105. (Figure 8c, right). The division of the wafer 500 can be realized by any known processes. In particular, it is also possible for the division to be carried out by suitable removal of carrier material during the production of the MEMS structure. In this case, a process known from the production of MEMS structures for the selective removal of material - e.g. an etching process - can be applied directly to the carrier material in order to achieve the division. Such an etching process can be provided as a separate step during the production of the MEMS structures. However, it is also possible to "remove" material in a process step provided for the production of MEMS structures.

[0124] If MEMS chips 100 are present without any protrusion areas 105 - regardless of whether they have been freed from originally present protrusion areas 105 by a post-processing method according to the invention (cf. Figures 2 to 7) or have already been manufactured without protrusion areas 105 (cf. Figure 8c) - they can, if this has not already been done, be arranged with a very small distance from one another on a base substrate plate 150, as is sketched in Figure 9a.

[0125] For handling the MEMS chips 100, a tool 600 is provided, with which the individual MEMS chips 100 can be grasped on two adjacent sides of the carrier material 104, so that the MEMS chips 100 can be arranged with the other two sides of the carrier material 104 directly adjacent to MEMS chips 100 already arranged on the base substrate plate 150. The tool 600 and its interaction with a MEMS chip 100 is shown in Figure 9b in two plan views and two corresponding partial sections, wherein the right-hand views each show the tool 600 in engagement, while in the left-hand views the tool 600 is still separate from the MEMS chip 100.

[0126] In order for the MEMS chips 100 to be gripped securely and precisely by the tool 600, the MEMS chips 100 have lateral recesses 108 in the area of ​​the carrier material 104, into which corresponding projections 601 on the tool 600, which is otherwise designed like a pair of pliers, can engage in a form-fitting manner.

[0127] In addition to the two recesses 108, which also show the orientation of the MEMS structures of the MEMS chip relative to the carrier material.

[0128] If recesses for the engagement of a handling tool 600 are provided only on two adjacent sides of the carrier material, but at least one side of the carrier material is free of recesses, the orientation of the MEMS structures 102 of the MEMS chip 100 relative to the carrier material 104 can be read from the arrangement of the recesses, thus ensuring the correct alignment of each MEMS chip 100 during its integration. Further recesses in a shape and arrangement comparable to a barcode can be provided on the carrier material 100 as a marking 109, in which the batch or serial number of the respective MEMS chip 100 is stored.

[0129] The recesses 108 and the marking 109 can be integrated into the carrier material 104 during the manufacture of the MEMS chip 100. In particular, the areas in question, which are usually at least temporarily located inside, can initially be filled with sacrificial material corresponding to a sacrificial material 202 in the separation region 200, which can be removed during the removal of the sacrificial material 202 in the separation region 200.

Claims

Patent claims 1. Method for post-processing MEMS chips (100) comprising MEMS structures (102) arranged on a carrier material (104) with at least one region of the MEMS chip laterally provided with MEMS structures (102) (100) projecting region (105) of projecting material, characterized in that at least one projecting region (105) is removed by separating the projecting material from the carrier material (104) of the MEMS chip.

2. Method according to claim 1, characterized in that at least one protruding region (105) is removed by creating a continuous gap (201) between the protruding region (105) and the carrier material (104) of the MEMS chip (100).

3. Method according to one of the preceding claims, characterized in that at least one protruding region (105) is removed by creating a predetermined breaking point (203) between the protruding region (105) and the carrier material (104) of the MEMS chip (100) and subsequently breaking open the predetermined breaking point (203).

4. Method according to one of claims 2 or 3, characterized in that in order to create a continuous gap (201) and / or a predetermined breaking point, a sacrificial material (202) arranged in this region and different from the projecting material is removed.

5. The method according to claim 4, characterized in that the sacrificial material (202) is removed by an etching process.

6. Method according to one of claims 2 or 3, characterized in that in order to create a continuous gap (201) and / or a predetermined breaking point (203), material is removed without leaving any residue, preferably by means of high-energy radiation.

7. Method according to claim 3, characterized in that in order to create a predetermined breaking point (203), material in the region of the predetermined breaking point (203) to be created is deliberately weakened, preferably by high-energy radiation.

8. Method according to claim 6 or 7, characterized in that a shadow mask (302) is used for beam shaping of the high-energy radiation.

9. Method according to one of claims 3 to 8, characterized in that a created predetermined breaking point (203) is broken by introducing shear stress (90) and / or tensile stress (91).

10. Method according to one of claims 3 to 8, characterized in that a created predetermined breaking point (203) is broken open by changing the temperature and / or by introducing a temperature gradient.

11. Method according to one of the preceding claims, characterized in that at least one protruding region (105) is designed to connect a protective cover (106) for the MEMS chip (100) and the protective cover (106) is preferably removed at the same time as the protruding region (105).

12. Method according to one of the preceding claims, characterized in that the MEMS chip (100) is a MEMS mirror array (101), preferably for photolithography, more preferably for EUV photolithography.

13. Method for handling MEMS chips (100) without areas (105) projecting beyond the MEMS structures (102) arranged on a carrier material (104), in particular after post-processing according to one of claims 1 to 12, characterized in that at least one lateral recess (108) is provided in the carrier material (104) and the handling of the MEMS chips (100) takes place by engagement of a tool (600) in the lateral recess(es).

14. The method according to claim 13, characterized in that at least two lateral recesses (108) are provided on two mutually adjacent sides of the carrier material (104).

15. Method according to claim 13 or 14, characterized in that markings (109) are arranged laterally on the carrier material (104).

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