TW202419385A - Microelectromechanical device - Google Patents

Abstract

Microelectromechanical device (110) comprising a carrier substrate (100) having a substrate surface (100a), and a plurality of MEMS modules (120), wherein each of the plurality of MEMS modules (120) comprises an ASIC layer (140) having an ASIC layer front side (140a) and an ASIC layer rear side (140b), a baseplate (160) having a baseplate front side (160a) and a baseplate rear side (160b), and a plurality of microelectromechanical components (130) having a component rear side (130b), wherein the baseplate (160) is arranged on the ASIC layer front side (140a) and the baseplate rear side (160b) is connected to the ASIC layer front side (140a) and the plurality of microelectromechanical components (130) are arranged on the baseplate front side (160a) and their component rear sides (130b) are connected to the baseplate front side (160a), wherein the ASIC layer (140) has an ASIC for controlling the plurality of microelectromechanical components (130), wherein the ASIC is connected to the microelectromechanical components (130) by way of electrical contacts (144), wherein the plurality of MEMS modules (120) are arranged on the substrate surface (100a) and the ASIC layer rear sides (140b) of the plurality of MEMS modules (120) are connected to the substrate surface (100a).

Description

MEMS devices

The present invention relates to the field of micro-electromechanical devices, in particular to micro-mirror arrays, and relates to a micro-electromechanical device; an illumination optical unit; an illumination system for projection exposure equipment; a corresponding projection exposure equipment and a method for manufacturing a micro-electromechanical device.

Devices comprising displaceable micromirrors arranged in a matrix, known as micromirror arrays or micromirror actuators, are used today in a variety of devices, such as smartphones, projectors, head-up displays, barcode readers, mask exposure units in semiconductor manufacturing, and microscopes. Corresponding micromirror arrays are known, for example, from DE 10 2013 208 446 A1, EP 0 877 272 A1 and WO 2010/049076 A2. Disclosures concerning suitable actuator units for displacing individual mirrors (i.e. micromirrors) in a micromirror array are described in detail, for example, in DE 10 2013 206 529 A1, DE 10 2013 206 531 A1 and DE 10 2015 204 874 A1.

According to the present invention, a micro-electromechanical device, an illumination optical unit including the micro-electromechanical device, an illumination system and a projection exposure device each having a corresponding illumination optical unit, and a method for manufacturing the micro-electromechanical device according to the present invention are provided.

According to a first aspect of the invention, a micro-electromechanical device is provided, comprising a carrier substrate having a substrate surface and a plurality of MEMS modules (MEMS: micro-electromechanical system). In this case, each of the plurality of MEMS modules comprises: an ASIC layer, preferably exactly one, having an ASIC layer front side and an ASIC layer rear side positioned opposite the ASIC layer front side, a base plate having a base plate front side and a base plate rear side opposite the base plate front side, and a plurality of micro-electromechanical components having component rear sides. The micro-electromechanical components do not need to be identical in their construction and/or function, although this may be the case. The base plate is arranged on the ASIC layer front side, and the base plate rear side is connected to the ASIC layer front side. Polymeric connections by welding or preferably sintering or eutectic bonding are particularly suitable for this, whereby electrical contacts are formed between the ASIC layer and the base plate. For example, a silver sintering paste can be used as a sintering material. A plurality of micro-electromechanical components are additionally arranged on the front side of the base plate, and their component rear sides are connected to the front side of the base plate. The ASIC layer of each of the MEMS modules has one or more ASICs (ASIC: Application Specific Integrated Circuit) for controlling a plurality of micro-electromechanical components, wherein the one or more ASICs are electrically connected to the micro-electromechanical components using at least a portion of the electrical contacts, wherein the electrical contacts are typically further led to the micro-electromechanical components in the base plate by electrical connections such as through holes. For example, in order to make electrical connections between further electronic components and micro-electromechanical components located on the carrier substrate, the ASIC layer may also optionally include an interposer and/or other components in addition to the ASIC. The ASIC layer of the MEMS module can be a continuous ASIC layer or a discontinuous ASIC layer. The term continuity of the ASIC layer means that all components of the ASIC layer are mechanically connected to each other through the layer itself. This mechanical connection through the ASIC layer between two components can be achieved by the components themselves and/or by other components of the layer, such as the ASIC, the interposer, suitable connecting elements, filling materials and/or bonding materials. In the case of a discontinuous ASIC layer, for example, this layer has components such as ASICs and/or interposers, which are not mechanically connected to each other through the layer itself. The ASIC layer thus has a gap. The electrical connection can be further guided by electrical contact points between the ASIC layer and the base plate. For example, a suitable interposer is in particular a silicon-based interposer with electrical connections, such as through-silicon vias (TSVs), such as copper-based through vias (Cu through vias). Multiple MEMS modules are arranged on the substrate surface of the carrier substrate, and the ASIC layers of the multiple MEMS modules are connected to the substrate surface on the back side. This connection is usually also implemented in a polymeric manner and is preferably implemented by sintering. Further electronic components on the carrier substrate can be, for example, further ASICs for controlling the entire electromechanical device, passive elements and/or connection elements (such as plugs, cables), for example for making electrical connections to external control devices such as computing units and for power supply purposes. The carrier substrate as a whole serves as a component carrier and may include electrical connections such as through-holes for guiding electrical signals from one surface of the carrier substrate to another surface of the carrier substrate. In this respect, it may be advantageous, for example, to arrange further electronic components on a substrate surface of the carrier substrate which is positioned relative to the substrate surface with the MEMS module. Furthermore, in order to enable a high fill factor, i.e. a close arrangement of the MEMS modules on the carrier substrate, the ASIC layer of the MEMS module may be shaped so that it does not protrude laterally beyond the base plate of the MEMS module. The ASIC layer of the MEMS module therefore preferably has the same or smaller dimensions than the base plate.

This microelectromechanical device therefore subdivides its multiple microelectromechanical components into individual groups, each group comprising multiple microelectromechanical components, which groups are referred to as MEMS modules in the context of the present invention. Multiple MEMS modules can each have, for example, exactly 2, 3, 4, 5, 6, 9, 12, 16, 20, 25, 30, 36, 42, 49, 56, 64, 72 or 81 multiple microelectromechanical components, and other numbers ≥ 2 are also conceivable. A plurality of MEMS components may be arranged, for example, in a rectangular grid consisting of rows and columns, for example, two rows and two columns, two rows and three columns, three rows and three columns, three rows and four columns, four rows and four columns, four rows and five columns, five rows and five columns, five rows and six columns, six rows and six columns, six rows and seven columns, seven rows and seven columns, seven rows and eight columns, eight rows and eight columns, eight rows and nine columns or nine rows and nine columns. Alternatively, for example, a hexagonal grid is conceivable. The electromechanical device according to the invention may include, for example, exactly 2, 3, 4, 5, 6, 9, 12, 16, 20, 25, 30, 36, 42, 49, 56, 64, 72 or 81 MEMS modules, other numbers ≥ 2 are also conceivable. The MEMS modules can also be arranged in a rectangular grid consisting of rows and columns, for example two rows and two columns, two rows and three columns, three rows and three columns, three rows and four columns, four rows and four columns, four rows and five columns, five rows and five columns, five rows and six columns, six rows and six columns, six rows and seven columns, seven rows and seven columns, seven rows and eight columns, eight rows and eight columns, eight rows and nine columns or nine rows and nine columns. Here, for example, a hexagonal grid is also conceivable as an alternative.

An advantageous aspect of subdividing a microelectromechanical device in this way is the reduction in structural complexity and susceptibility to failures achieved by the subdivision into MEMS modules. It has been established that a plurality of MEMS modules with a reduced number of microelectromechanical components are easier to handle in the manufacturing process than a single unit with the same total number of microelectromechanical components. In particular, the yield in the manufacturing process can be significantly increased by the method according to the invention, since MEMS modules which exclusively comprise fully functional microelectromechanical components can be selected in a targeted manner during manufacturing. Furthermore, it is conceivable to further connect a plurality of such microelectromechanical devices according to the invention to form a superordinate unit, for example in order to cover a larger area than is achievable with a single microelectromechanical device according to the invention.

A particularly important embodiment of the invention is the use of micromirrors as microelectromechanical components. The microelectromechanical device can thus be in particular a micromirror array. In this case, each of the plurality of microelectromechanical components comprises a mirror element having a reflective surface for reflecting light, and a displacement unit for displacing the mirror element of the respective microelectromechanical component, wherein one or more ASICs are configured to control the displacement unit. In this case, displacement means movement relative to at least one degree of freedom. The displacement can include linear movement and rotation. The mirror element can be or can in particular include a Bragg mirror. The displacement unit can be, for example, an electrostatic actuator, for example with comb electrodes. Suitable actuators are described, for example, in DE 10 2013 206 529 A1, DE 10 213 206 531 A1 and DE 10 2015 204 874 A1.

It is advantageous to subdivide the microelectromechanical device according to the invention into MEMS modules, in particular if the carrier substrate of the microelectromechanical device according to the invention consists essentially of a first material and the plurality of MEMS modules consists essentially of a second material, wherein the first material has a first thermal expansion coefficient α ₁ and the second material has a second thermal expansion coefficient α ₂ which is different from the first thermal expansion coefficient. Typically, the first material (i.e. the material of the carrier substrate) comprises a ceramic (e.g. an alumina-based ceramic) or is a ceramic (e.g. an alumina-based ceramic). The second material (i.e. the material of the MEMS modules) typically comprises a semiconductor material (in particular silicon, e.g. single-crystalline silicon and/or polycrystalline silicon) or is a semiconductor material (in particular silicon, e.g. single-crystalline silicon and/or polycrystalline silicon). The invention can be used very particularly advantageously if the first coefficient of thermal expansion α1 and the second coefficient of thermal expansion α2 have a relatively large difference _, i.e. for example have a ratio of α1 / α2 _{≥1.5 to} one another. In the context of the production process of microelectromechanical devices _, such as micromirror arrays, temperatures which occur, for example as a result of welding or sintering, are generally significantly higher than in the rest state or other operating states of the device. In the case of the production of such devices from different materials with different coefficients of thermal expansion, such as ceramics and silicon, mechanical stresses which are caused by the different coefficients of thermal expansion, which are also referred to as thermal stresses, can occur. Such thermal stresses are frozen during assembly (i.e. welding or sintering) and dissipated during the life of the device. This can lead to structural deformations and/or damage to the device, which can significantly impair its functionality. For example, in the case of a micromirror array, the position of the individual lenses can be altered in an undesirable manner. By subdividing the microelectromechanical components of a microelectromechanical device into spatially smaller MEMS modules consisting of a second material and applying them to a carrier substrate consisting of a first material, the thermal stresses caused by the use of different materials can be significantly reduced compared to corresponding microelectromechanical devices of the prior art.

In order to achieve a particularly high coverage of the available area by means of microelectromechanical components, it is advantageous if a plurality of MEMS modules have a substantially rectangular, preferably square, substrate surface and are arranged in a rectangular, preferably square grid. Alternatively, it is also advantageous if the MEMS modules have a substantially hexagonal substrate surface and are arranged in a hexagonal grid. A substantially rectangular or hexagonal substrate surface means in this context that slight deviations from a strictly rectangular or respectively hexagonal substrate surface are conceivable, for example due to rounded corners and/or concavities or convexities or other irregularities. In this case, it is particularly advantageous if each MEMS module is only at the minimum possible distance from its neighboring MEMS modules. For example, each of the plurality of MEMS modules may be at a distance of ≤50 μm, preferably ≤10 μm, and even more preferably ≤5 μm from at least one adjacent MEMS module, and preferably from all adjacent MEMS modules. In this case, a MEMS module adjacent to a MEMS module arranged in a grid is also arranged in the grid and directly adjacent to the MEMS module, in the sense that no other MEMS module is located between the MEMS module and the adjacent MEMS module in the grid. In the case where the MEMS modules are arranged in a rectangular grid, MEMS modules located on diagonals opposite to each other should also be understood as MEMS modules adjacent to each other. The base surface of the MEMS module is typically defined by the carrier substrate of the MEMS module.

It is therefore also particularly advantageous if each of the plurality of microelectromechanical components in each of the plurality of MEMS modules has a substantially rectangular, preferably square, base surface or a substantially hexagonal base surface. A substantially rectangular or hexagonal base surface means that slight deviations from a rectangular or respectively hexagonal base surface are conceivable, for example due to indentations and/or protrusions at the corners and/or edges of the base surface, such as rounding and/or chamfering of the base surface.

In order to be able to place (i.e., grasp, move and/or position) the MEMS module on the substrate surface by means of a suitable device (handling device) during the manufacturing process, the MEMS module must be able to be grasped without being damaged, and in particular particularly sensitive areas such as reflective surfaces are not touched. For this purpose, the MEMS modules can each include at least one, for example two, preferably at least three, particularly preferably four or more handling areas that are not covered by the plurality of microelectromechanical components of the MEMS module. In this case, a handling area is an area of the MEMS module that is suitable for use by a handling device in order to be able to grasp, move and/or position the MEMS module without damaging the MEMS module in the process. As an alternative or in addition to the processing area, the MEMS module can be provided with a frame at which a suitable processing device (for example by decompression) can grasp and subsequently move and/or position the MEMS module. The MEMS module can also be provided with a frame, which at least partially surrounds the MEMS module and is used during the decompression generated in the frame area in interaction with the corresponding decompression generating processing device. This frame can alternatively or additionally also be used to avoid or at least reduce the entry of dust into the MEMS module. For example, this frame can surround the microelectromechanical components of the MEMS module without the processing area. This frame can also be made thinner than a frame designed to enable the MEMS module to be grasped.

Each of the at least one processing area of the MEMS module can be formed, for example, by a chamfered or grooved (provided with grooves) lateral edge of one of the multiple microelectromechanical components of the MEMS module. In the context of the present invention, a groove is understood to mean a cut along an edge. The groove can have any desired shape, i.e., it can be circular or rectangular, for example. In the context of the present invention, a lateral edge of a MEMS module is understood to mean a vertically extending edge of the MEMS module. The lateral edge corresponds to the corner of the substrate surface of the MEMS module. A lateral cutout (cutout in the side surface) of any desired shape (e.g., semicircular or rectangular) of a microelectromechanical component can also be used as a processing area, wherein such a cutout in the side surface is preferably centrally arranged in the side surface. Based on their known position within the MEMS module, the processing areas can also be used to bring the MEMS module into a defined position relative to the substrate and in particular also relative to adjacent MEMS modules.

According to another preferred embodiment, the microelectromechanical device includes a plurality of flexible elements for reducing mechanical stresses between a plurality of MEMS modules, wherein each of the plurality of flexible elements is part of a MEMS module of the plurality of MEMS modules and is arranged at and/or in a side surface of the MEMS module. Such flexible elements are advantageous, in particular if the MEMS modules are positioned at no distance or only a small distance relative to each other during the manufacturing process, so as to achieve the highest possible proportion of the area of the carrier substrate occupied by the MEMS modules, i.e. a high fill factor. If mechanical stresses occur between the MEMS modules due to the small distances between the MEMS modules during or after the manufacturing process, the flexible elements counteract the mechanical stresses. The flexible element for reducing mechanical stresses between at least two of a plurality of MEMS modules thus corresponds to a spring whose restoring force counteracts the mechanical stresses. Mechanical stresses can occur in particular in the form of thermal stresses caused by different coefficients of thermal expansion of the materials used: if a first material (usually a ceramic, such as an alumina ceramic, for example) which substantially constitutes the carrier substrate has a greater coefficient of thermal expansion than a second material (usually a semiconductor material such as silicon) which substantially constitutes the MEMS module, both the carrier substrate and the MEMS module contract during cooling, for example after a high temperature step in the manufacturing method, such as bonding. However, due to the lower coefficient of thermal expansion of the second material, the MEMS module contracts less than the carrier substrate. Therefore, if two adjacent MEMS modules are arranged with no distance or only a small distance relative to each other, there is a risk that the two adjacent MEMS modules will press against each other. Thermal stresses thus arise between the MEMS modules and can lead to damage to the microelectromechanical device. Such thermal stresses can be counteracted by flexible elements. Overall, this therefore makes it possible to ensure mechanical stability and a high fill factor at the same time.

A particularly advantageous embodiment of a flexible element is provided by the fact that each of a plurality of flexible elements is arranged in a side surface of a MEMS module and comprises a web, wherein the web is part of the side surface of the MEMS module and is formed by a recess of the MEMS module and preferably has an external protrusion for making contact points to adjacent MEMS modules. In particular, this flexible element can be realized by means of a recess in a base plate of the MEMS module. This flexible element can be realized in a simple manner by means of a layered construction of this base plate during the manufacturing process.

Preferably, each of the plurality of MEMS modules has one or more flexible elements, wherein the plurality of MEMS modules are arranged so that the one or more flexible elements of each of the plurality of MEMS modules are arranged adjacent to other MEMS modules in the plurality of MEMS modules in various cases. A flexible element of a MEMS module is arranged adjacent to another MEMS module if the other MEMS module is arranged adjacent to the flexible element of the MEMS module and the flexible element faces the adjacent MEMS module.

A particularly preferred arrangement of the present invention is provided based on the following fact, wherein a first MEMS module among a plurality of MEMS modules comprises a first base plate having at least one first flexible element among a plurality of flexible elements and a second MEMS module among a plurality of MEMS modules comprises a second base plate having at least one second flexible element among a plurality of flexible elements, wherein the first MEMS module and the second MEMS module are arranged relative to each other such that at least one first flexible element is arranged adjacent to the second base plate and at least the second flexible element is arranged adjacent to the first base plate. In this case, the flexible element of one MEMS module is arranged adjacent to the base plate of the other MEMS module, and if the other MEMS module is arranged adjacent to the flexible element of the MEMS module, the flexible element is oriented towards the adjacent MEMS module and the flexible element is located at the level of the base plate of the other MEMS module. Preferably, the first flexible element and the second flexible element are arranged offset relative to each other in this case. In this case, it is conceivable that the flexible elements are offset horizontally relative to each other and/or vertically relative to each other, i.e., are not positioned relative to each other in direct mirror symmetry. Preferably, the flexible element comprises individual protrusions, which serve to produce contact points or contact areas when one MEMS module approaches an adjacent MEMS module, for example due to temperature changes. The flexible element is dimensioned and positioned so that, in this approaching situation, a protrusion of the flexible element of one MEMS module strikes a static area of an adjacent MEMS module. In this case, the static area is an area of the MEMS module, preferably an area of its base plate, which is not part of the flexible element of the MEMS module. Such an arrangement and positioning of the flexible element makes it possible to particularly effectively compensate for thermal stresses arising due to different expansion coefficients of the materials of the MEMS module and the carrier substrate without endangering the structural integrity of the microelectromechanical components of the MEMS module.

According to a second aspect of the invention, an illumination optical unit for a micro-electromechanical device for directing illumination radiation to an object field is proposed, the illumination optical unit comprising at least one micro-electromechanical device according to the invention, wherein each of a plurality of micro-electromechanical components comprises a mirror element with a reflective surface and a displacement unit for displacing the mirror element of the respective micro-electromechanical component, wherein one or more ASICs are configured to control the displacement unit. The illumination optical unit according to the invention thus uses the micro-electromechanical device according to the invention as a micro-mirror array. It may also in particular comprise a plurality of such micro-mirror arrays according to the invention, for example in order to achieve a larger overall micro-mirror array by means of the arrangement of such a plurality of micro-mirror arrays, which makes it possible to deflect an incident light beam having a larger beam diameter.

According to a third aspect, an illumination system for a projection exposure device is also proposed, which includes an illumination optical unit according to the present invention and a radiation source, in particular an EUV radiation source.

According to a fourth aspect, a lithography projection exposure device is proposed, which includes an illumination optical unit according to the present invention and a projection optical unit for projecting a magnification mask arranged in an object field into an image field.

The illumination optical unit according to the invention, the illumination system according to the invention and the projection exposure apparatus according to the invention can be part of an EUV lithography apparatus. For these, an adjustable optical path to the mask (also called a doubling mask) is advantageous, which can be realized by an array of micromirrors in the optical path as a microelectromechanical device according to the invention. The reflective surface of the mirror element can be provided with a Bragg coating, which provides particularly good reflection for the central wavelength of the light used for exposure.

For further details about the general settings of the corresponding projection exposure apparatus and the associated illumination optical unit and the associated illumination system, reference should be made to DE 10 2015 204 874 A1 and DE 10 2016 213 026 A1, which are hereby fully incorporated into the present application as part of it.

According to a fifth aspect of the present invention, a method for manufacturing a microelectromechanical device is provided, preferably a microelectromechanical device according to the first aspect of the present invention, which includes a carrier substrate and a plurality of MEMS modules. Each MEMS module includes preferably exactly one ASIC layer, which has one or more ASICs (and optionally also other components such as one or more interposers) and an ASIC layer front side and an ASIC layer back side, a base plate, which has a base plate front side and a base plate back side, and a plurality of microelectromechanical components, wherein the base plate is arranged on the ASIC layer front side and the base plate back side is connected to the ASIC layer front side. The ASIC layer of the MEMS module can be configured as a continuous ASIC layer or a discontinuous ASIC layer. The method according to the invention involves providing a MEMS substrate having a structure for a microelectromechanical component and a base plate for a plurality of MEMS modules. The provided MEMS substrate thus comprises a structure for a microelectromechanical component and a base plate for a plurality of MEMS modules. Such a substrate is usually in the form of a wafer (MEMS wafer) and can be manufactured by the method described, for example, in DE 10 2015 206 996 A1; this also involves providing an ASIC substrate having a structure for an ASIC layer of a microelectromechanical device, likewise usually in the form of a wafer (ASIC wafer). A coupling substrate, usually in the form of a coupling wafer, is manufactured from these two substrates by connection (in the case of wafers: wafer bonding), in particular by cohesive connections (for example soldering, sintering, for example using silver sintering paste, or eutectic bonding), wherein for each of the plurality of MEMS modules, a plurality of assigned electrical contacts are formed between the MEMS substrate and the ASIC substrate. This coupling substrate is then divided along predefined separation lines, for example along a lattice structure, in order to obtain a plurality of MEMS modules. Furthermore, a carrier substrate is provided, on which further electronic components may have been mounted, if appropriate. A plurality of MEMS modules are placed on the substrate surface of the carrier substrate. This is followed by polymerically connecting the ASIC layers of the plurality of MEMS modules to the substrate surface (e.g. by soldering or sintering, e.g. using a silver sintering paste) on their back sides. The method is preferably implemented for manufacturing a microelectromechanical device whose MEMS modules comprise processing areas for placing the MEMS modules on a substrate surface of a carrier substrate. This enables the MEMS modules to be simply placed on the substrate surface without limiting the fill factor. It is also preferred to test the microelectromechanical structures of the MEMS substrate and/or the ASIC structures of the ASIC substrate to ensure functionality before the manufacturing process of the coupling substrate. Preferably, to ensure functionality, it is also possible to perform testing of the MEMS module after manufacturing the coupling substrate and/or to perform testing of the entire completed micro-electromechanical device after back-side polymer bonding of the ASIC layers of multiple MEMS modules to the substrate surface.

Advantages of the present invention

The present invention provides a method for a microelectromechanical device, for example, a micromirror array, comprising a plurality of microelectromechanical components arranged on the same carrier substrate, if the thermal expansion coefficient of the carrier substrate is different from the thermal expansion coefficient of the microelectromechanical components. By means of the method according to the present invention, harmful thermal stresses due to the difference are counteracted. At the same time, by means of various embodiments of the present invention, it is possible to ensure a high fill factor by means of the microelectromechanical components.

By subdividing the microelectromechanical component into individual smaller units (MEMS modules) according to the invention, it is possible in particular to reduce thermal stresses that freeze during the manufacturing process. At the same time, by using processing areas and flexible elements between the microelectromechanical components, it is possible to achieve high fill factors with the MEMS modules and thus with the microelectromechanical components despite this separation. The microelectromechanical device according to the invention is therefore particularly suitable for applications in which high precision and high fill factors are simultaneously important, such as in the case of certain optical units for EUV lithography.

In the following description of the embodiments of the present invention, the same or similar elements are indicated by the same reference numerals, and repeated descriptions of these elements in individual cases are omitted. For the sake of clarity, in the case of a large number of identical or similar elements, if the same or similar aspects of these elements are revealed by the drawings and/or the description of the drawings, these elements are simply selected to provide reference numerals for exemplary purposes. The drawings only schematically illustrate the subject matter of the present invention.

FIG1 shows a schematic diagram of a portion of an exemplary microelectromechanical device 110 according to the present invention of a micromirror array in a side view. In the example shown, two MEMS modules 120 are arranged on a substrate surface 100a of a carrier substrate 100, each of which includes a plurality of microelectromechanical components 130, four of which are shown in various cases in FIG1. In the case shown, the microelectromechanical components 130 are micromirrors. These micromirrors each include a mirror element 134, which in turn has a reflective surface 136 for reflecting light. These mirror elements 134 can be moved by means of a displacement unit 132. An ASIC is used to control the displacement unit, which is arranged in the form of a die below the displacement unit in an ASIC layer 140 and is also part of each MEMS module 120. Further electronic components (eg also for controlling the displacement unit, eg in the form of other ASICs) may be arranged (not shown), for example, on the rear side 100 b of the carrier substrate 100 .

Within the MEMS module 120, the micro-electromechanical components 130 are arranged on the front side 160a of the base plate 160. In this case, the base plate front side 160a is connected to the back side 130b of the micro-electromechanical components 130. In the example shown, two base plates 160 are visible, with four respective micro-electromechanical components 130 shown being located on each base plate. The micro-electromechanical components 130 are connected to the ASICs of the respective ASIC layers 140 via electrical contacts 144. The ASICs of the ASIC layers 140 can in turn be connected to further electronic components (not shown) via electrical contacts 146, which can be arranged on the carrier substrate 100, for example. Furthermore, for example through-silicon vias (TSVs) 142 may be present in the ASIC layer 140 and may be used, for example, to make electrical connections between such further electronic components on the carrier substrate 100 and the micro-electromechanical component 130. Such vias 142 may be realized, for example, by an interposer, which may likewise be part of the ASIC layer 140, or by a die of the ASIC.

The MEMS modules 120 shown have respective flexible elements 150. In this case, the flexible element 150a of the left MEMS module 120a is arranged adjacent to the right MEMS module 120b, i.e. oriented towards the latter. The flexible element 150b of the right MEMS module 120b is oriented in such a way that it faces away from the first MEMS module 120a. In this case, the flexible element 150 is realized as part of the area of the base plate 160. More precisely, the flexible element 150 shown in each case extends over a part of the side surface of the base plate 160 of the MEMS module 120; the upper area 165 of the base plate 160 is not used for the flexible element 150.

Furthermore, in each case two processing areas 180 can be seen in FIG. 1 for each MEMS module 120, which are located in each case on two of the four micro-electromechanical components 130. In the case shown, the processing areas 180 are areas which can be realized, for example, by grooved transverse edges 190 of the micro-electromechanical components 130. If a suitable decompression-based processing device is used, it can be advantageous if the MEMS module 120 is at least partially delimited to the outside by means of a frame 170 in order to simplify the production of decompression in a bounded area. At the same time, this frame 170 can be used to protect the MEMS module 120 from dust particles. For illustration purposes, the direction of these edges 190 without grooves is shown in dashed lines. By means of these processed areas 180 , the MEMS module 120 can be placed on the carrier substrate 100 without the risk of damaging the MEMS module 120 and in particular the micro-electromechanical component 130 having the sensitive reflective surface 136 .

2A shows in plan view a schematic diagram of a portion of a second exemplary microelectromechanical device 210 according to the present invention, which comprises four mutually adjacent MEMS modules 220a, 220b, 220c, 220d with processing areas 280a, 280b, 280c, 280d. In this case, the four MEMS modules 220 each have 16 microelectromechanical components 230 and have four processing areas 280. These processing areas 280 are realized by groove-shaped transverse edges 290 of the MEMS modules 220. In this case, the transverse edges 290 correspond to the corners of the substrate surface of the MEMS module, and the dotted lines illustrate the direction of the square substrate surface in the area of the processing area. The microelectromechanical device 210 in FIG. 2A does not show any flexible areas, but the latter are conceivable. It is also conceivable that the processing area 280 has a shape different from the shape shown, such as an angular shape; for an example of this, please refer to FIG. 2B. Since the MEMS modules 280 intersect in the center, the four processing areas 280 located there form a circular cutout. A processing device with an operator that is set to a cylindrical shape according to the cutout can arrange all four MEMS modules relative to each other in a defined manner by means of such an operator. The processing device can therefore be constructed so that the MEMS modules are automatically arranged in a manner that appropriately matches adjacent MEMS modules during the placement of the MEMS modules by the processing device. Furthermore, the frame 270 (solid line) may in various cases protect the MEMS module 280 from dust particles and/or support them during decompression when the MEMS module is gripped by a corresponding decompression handling device.

FIG. 2B is a modification of FIG. 2A and shows other possibilities for realizing the processing area 280 based on four additional adjacent MEMS modules 220e, 220f, 220g, 220h. The processing area 280e of the MEMS module 220e is realized as a rectangular cutout (again, a groove is within the meaning of the invention) of the lateral edge 290. In contrast, the MEMS module 220f uses a chamfered lateral edge 290. Finally, the adjacent MEMS modules 220g and 220h use a centrally placed semicircular cutout on the lateral surface of the MEMS module. As shown, in the case of the MEMS modules 220g and 220h, the semicircular cutouts 280g, 280h at the adjacent lateral surfaces complement each other to form a circle. Thus, in a manner similar to the case of the processing areas 280a, 280b, 280c, 280d, 280e, 280f arranged in the corners, the lateral processing areas 280g, 280h make it possible for suitable processing devices to arrange the MEMS module 220 in a defined manner relative to each other. Other shapes such as rectangular cutouts are also conceivable as processing areas 280g, 280h instead of semicircular cutouts.

Finally, FIG3 shows in the upper sub-figure A a schematic diagram of a portion of a third exemplary micro-electromechanical device 310 according to the present invention with a flexible element 350 in a plan view, showing two adjacent MEMS modules 320. Furthermore, FIG3 shows in sub-figure B a schematic diagram of a portion 320s of a MEMS module 320a from the left side of sub-figure A in a side view. For greater clarity, the ASIC layer of the MEMS module 320a and the carrier substrate on whose surface the MEMS module 320a is arranged are not shown in sub-figure B.

In the illustrated MEMS device 310, the flexible element 350 is implemented by a recess 354 in a base plate 360 and is composed of a web having a vertically extending external protrusion 352, which is a portion of the side surface of the base plate 360 corresponding to the MEMS module 320. Each MEMS module 320 is composed of 16 MEMS components 330, and the position of the lower recess 354 in the upper sub-figure A is marked with a dotted line for illustration. As shown in sub-figure B, the flexible element 350 does not extend over the entire height of the side surface of each base plate 360; rather, a specific area 365 of the side surface of the base plate 360 is not occupied by the flexible element 350, so that all the micro-electromechanical components 330 can be stably arranged on the top side 360a of the base plate 360. In sub-figure B, the extension area of the flexible element 350 is also marked by a dotted line 356. In order to ensure sufficient mobility of the flexible element 350, as shown in the figure, the flexible element 350 can be at least partially separated from the area 365 (cutout 358).

The flexible elements 350 of the left MEMS module 320a and the adjacent right MEMS module 320b are shown arranged in respective base plates 360 of the two MEMS modules 320 so that they are arranged offset relative to each other. In this case, the flexible element on the right surface of the left MEMS module 320a and the flexible element on the left surface of the right MEMS module 320b are sized and positioned so that if the left MEMS module 320a approaches the right MEMS module 320b, such as may occur due to temperature changes, for example, the protrusion 352a of the flexible element on the right surface of the left MEMS module 320a hits the static area of the right MEMS module 320b. Conversely, the protrusion 352b of the flexible element on the left side surface of the right MEMS module 320b hits the static area of the left MEMS module 320a. In this case, the static area is considered to refer to the base plate 360 that is a part of the non-flexible element part. By the shown arrangement of the flexible elements 352a, 352b, the thermal stress caused by the different materials of the MEMS modules 320a, 320b and the carrier substrate is offset without endangering the micro-electromechanical component 330.

Finally, FIG. 4 schematically shows a flow chart of a method for manufacturing a micro-electromechanical device 110, 210, 310 according to the present invention, wherein the micro-electromechanical device 110, 210, 310 comprises a carrier substrate 100 and a plurality of MEMS modules 120, 220, 320, wherein each MEMS module 120, 220, 320 comprises: an ASIC layer 140, which comprises a front surface of the ASIC layer; The method comprises providing 410 a MEMS substrate having a structure of the substrate 160, 360 for the micro-electromechanical components 130, 230, 330 and the plurality of MEMS modules 120, 220, 320, and a substrate 160, 360 having a substrate front side 160a, 360a and a substrate back side 160b, and a plurality of micro-electromechanical components 130, 230, 330, wherein the substrate 160, 360 is arranged on the ASIC layer front side 140a, and the substrate back side 160b is connected to the ASIC layer front side 140a. This involves providing (step) 410 a MEMS substrate having a structure of the substrate 160, 360 for the micro-electromechanical components 130, 230, 330 and the plurality of MEMS modules 120, 220, 320. This also involves providing (step) 420 an ASIC substrate having a structure of an ASIC layer 140 for a plurality of MEMS modules 120, 220, 320. Thereby, a coupling substrate is produced (step) by polymer connection, such as soldering, sintering or eutectic bonding, wherein a plurality of assigned electrical contact points 144 are formed for each of the plurality of MEMS modules 120, 220, 320 between the MEMS substrate and the ASIC substrate. Subsequently, the coupling substrate is divided (step) along predefined separation lines, such as a lattice structure, to obtain a plurality of MEMS modules. Furthermore, a carrier substrate 100 is provided (step), on which further electronic components and/or other components can be mounted, if appropriate. The plurality of MEMS modules 120, 220, 320 are placed (step) on the substrate surface 100a of the carrier substrate 100. Finally, in step 470, the ASIC layer rear sides 140b of the plurality of MEMS modules 120, 220, 320 are polymer-connected to the substrate surface 100a.

The method is preferably implemented for manufacturing a microelectromechanical device 110, 210, 310, whose MEMS module 120, 220, 320 includes a processing area 180, 280 for placing the MEMS module 120, 220, 320 on the substrate surface 100a of the carrier substrate 100. This allows the MEMS module 120, 220, 320 to be simply placed on the substrate surface 100a without strictly limiting the fill factor relative to the MEMS module 120, 220, 320. Also preferably, the microelectromechanical structure of the MEMS substrate is tested (step) 415 and/or the ASIC structure of the ASIC substrate is tested (step) 425 to ensure functionality before the process of manufacturing the coupled substrate. Additionally or alternatively, to ensure functionality, testing (step) 445 of the MEMS modules 120, 220, 320 may be performed after manufacturing the coupling substrate and/or the entire completed micro-electromechanical device 110, 210, 310 may be tested (step) 475 after the ASIC layer back side 140b of multiple MEMS modules 120, 220, 320 are polymer-connected to the substrate surface 100a.

The present invention is not limited to the exemplary embodiments described herein and the aspects emphasized therein. On the contrary, within the scope set forth in the patent application, a large number of modifications within the capabilities of those skilled in the art are possible.

100: carrier substrate 110,210,310: micro-electromechanical device 100a: substrate surface 100b: rear side 120,220,220a,220b,220c,220d,220e,220f,220g,220h,280,320: MEMS module 120a,320a: left MEMS module, first MEMS module 120b,320b: right MEMS module, second MEMS module 130,230: micro-electromechanical component 130b: rear side of component 132: displacement unit 134: mirror element 136: reflective surface 140: ASIC layer 140a: front side of ASIC layer 140b: rear side of ASIC layer 142: through hole 144,146: electrical contact point 150,150a,150b,250,350: flexible element 160,360: bottom plate, first bottom plate 160a,360a: bottom plate front side, front side 160b: bottom plate rear side 165: upper area 170: frame 180,280,280a,280b,280c,280d,280e,280f: processing area 190: grooved transverse edge, edge 280g,280h: processing area, semicircular cutout, cutout 290: grooved transverse edge, transverse edge 320s: part 350a: at least one first flexible element 350b: at least one second flexible element 352,352a,352b: protrusion 354: recess 356: dashed line 358: cutout 360a: top side 365: specific area, area 410,415,420,425,430,440,445,450,460,470,475: steps A,B: sub-images

The embodiments of the present invention are explained in more detail with reference to the drawings and the following description. In the drawings:

[FIG. 1] is a schematic diagram showing a portion of an exemplary micro-electromechanical device according to the present invention in a side view;

[FIG. 2A] A schematic diagram showing in plan view a portion of a second exemplary micro-electromechanical device having a processing area according to the present invention;

[FIG. 2B] A schematic diagram showing in plan view a portion of a variation of a second exemplary micro-electromechanical device according to the present invention having other processing areas;

[FIG. 3] A schematic diagram showing a portion of a third exemplary micro-electromechanical device having a flexible element according to the present invention in side view and plan view; and

[FIG. 4] A flow chart schematically showing a method for manufacturing a micro-electromechanical device according to the present invention.

100: Carrier substrate

110:Micro-electromechanical devices

100a: Substrate surface

100b: rear side

120:MEMS module

120a: Left MEMS module, first MEMS module

120b: right MEMS module, second MEMS module

130:Micro-electromechanical components

130b: Rear side of assembly

132: Displacement unit

134:Mirror element

136:Reflective surface

140: ASIC layer

140a: ASIC layer front side

140b: Back side of ASIC layer

142:Through hole

144,146: Electrical contact points

150,150a,150b: Flexible element

160: Bottom plate, first bottom plate

160a: Front side of the base plate, front side

160b: rear side of the base plate

165: Upper area

170:Framework

180: Processing area

190: grooved transverse edge, edge

Claims (15)

A micro-electromechanical device (110, 210, 310) comprises a carrier substrate (100) having a substrate surface (100a) and a plurality of MEMS modules (120, 220, 320), wherein each of the plurality of MEMS modules (120, 220, 320) comprises an ASIC layer (140) having an ASIC layer front side (140a) and an ASIC layer rear side (140b), a base plate (160, 360) having a base plate front side (160a, 360a) and a base plate rear side (160b), and a plurality of micro-electromechanical components (130, 230, 330) having a component rear side (130b), wherein the base plate (160, 360) is arranged on the front side (140a) of the ASIC layer, and the back side (160b) of the base plate is connected to the front side (140a) of the ASIC layer, and the plurality of micro-electromechanical components (130, 230, 330) are arranged on the front side (160a, 360a) of the base plate, and their component back sides (130b) are connected to the front side (160a, 360a) of the base plate, wherein the ASIC layer (140) has one or more ASICs for controlling the plurality of micro-electromechanical components (130, 230, 330), wherein the one or more ASICs are connected to the micro-electromechanical components (130, 230) via electrical contacts (144), The multiple MEMS modules (120, 220, 320) are arranged on the substrate surface (100a), and the rear side (140b) of the ASIC layer of the multiple MEMS modules (120, 220, 320) is connected to the substrate surface (100a). A microelectromechanical device (110, 210, 310) as described in claim 1, wherein each of the plurality of microelectromechanical components (130, 230, 330) comprises a mirror element (134) having a reflective surface (136), and a displacement unit (132) for displacing the mirror element (134) of each microelectromechanical component (130, 230, 330), wherein the one or more ASICs are configured to control the displacement unit (132). A microelectromechanical device (110, 210, 310) as described in claim 1 or 2, wherein the carrier substrate (100) is substantially composed of a first material, preferably ceramic, and the plurality of MEMS modules (120, 220, 320) are substantially composed of a second material, preferably Si, wherein the first material has a first thermal expansion coefficient _α1 and the second material has a second thermal expansion coefficient _α2 different from the first thermal expansion coefficient _α1 , wherein the first thermal expansion coefficient _α1 and the second thermal expansion coefficient _α2 preferably have a ratio _α1 / _α2 ≥1.5 relative to each other. A microelectromechanical device (110, 210, 310) as described in claim 1, wherein the plurality of MEMS modules (120, 220, 320) have a substantially rectangular, preferably square, base surface and are arranged in a rectangular, preferably square grid or have a substantially hexagonal base surface and are arranged in a hexagonal grid, wherein preferably, each of the plurality of MEMS modules (120) is ≤50 μm, preferably ≤10 μm, and particularly ≤10 μm away from at least one adjacent MEMS module (120), and preferably from all adjacent MEMS modules (120). A micro-electromechanical device (110, 210, 310) as described in claim 4, wherein each of the multiple micro-electromechanical components (30, 230) in each of the multiple MEMS modules (120, 220) has a substantially rectangular, preferably square, or substantially hexagonal base surface. A microelectromechanical device (110, 210, 310) as described in claim 5, wherein the MEMS modules (120, 220, 320) each include at least one, preferably at least three, and particularly preferably four or more processing areas (180) not covered by the multiple microelectromechanical components (130, 230, 330) of the MEMS module (120, 220, 320), so as to place the MEMS module (120, 220, 320) on the substrate surface (100a). A microelectromechanical device (110, 210, 310) as described in claim 6, wherein each of the at least one processing area (180, 280) of each MEMS module (120, 220, 320) is formed by a chamfered or grooved lateral edge (190, 290) or a cutout (280h, 280g) of a side surface of one of the multiple microelectromechanical components (130, 230, 330) of the MEMS module (120, 220, 320). A microelectromechanical device (110, 210, 310) as described in claim 4, wherein the microelectromechanical device (110, 210, 310) includes a plurality of flexible elements (150, 350) for reducing mechanical stress between at least two of the plurality of MEMS modules (120, 220, 320), wherein each of the plurality of flexible elements (150, 350) is a part of one of the plurality of MEMS modules (120, 220, 320) and is arranged at and/or in a side surface of the MEMS module (120, 220, 320). A microelectromechanical device (110, 210, 310) as described in claim 8, wherein each of the plurality of flexible elements (150, 350) is arranged in a side surface of a MEMS module (120, 220, 320) and includes a web, wherein the web is a portion of the side surface of the MEMS module (120, 220, 320) and is formed by a recess (354) of the MEMS module (120, 220, 320), preferably by a base plate (160, 360) of the MEMS module (120, 220, 320), and preferably has an external protrusion (352). A microelectromechanical device as described in claim 8 or 9, wherein each of the multiple MEMS modules (120, 220, 320) has one or more of the multiple flexible elements (150, 350), and wherein the multiple MEMS modules (120, 220, 320) are arranged so that the one or more flexible elements (150, 350) of each of the multiple MEMS modules (120, 220, 320) are arranged in various cases to be adjacent to other MEMS modules (120, 220, 320) of the multiple MEMS modules (120, 220, 320). A microelectromechanical device (110, 210, 310) as described in claim 8, wherein a first MEMS module (120a, 320a) of the plurality of MEMS modules (120, 220, 320) comprises a first base plate (160, 360) having at least one first flexible element (350a) of the plurality of flexible elements (150, 250) and a second MEMS module (120b, 320b) of the plurality of MEMS modules (120, 220, 320) comprises a first base plate (160, 360) having at least one first flexible element (350a) of the plurality of flexible elements (150, 250) The invention relates to a second base plate (160, 360) of at least one second flexible element (350b) in the element (150, 250), wherein the first MEMS module (120a, 320a) and the second MEMS module (120b, 320b) are arranged relative to each other so that the at least one first flexible element (350a) is arranged adjacent to the second base plate (160, 360) and the at least second flexible element (350b) is arranged adjacent to the first base plate (160, 360) and they are preferably arranged offset relative to each other. An illumination optical unit for a projection exposure apparatus for directing illumination radiation to an object field comprises one or more micro-electromechanical devices (110, 210, 310) according to claim 2 and preferably according to any one of claims 3 to 11. An illumination system for a projection exposure device, comprising an illumination optical unit according to claim 12 and a radiation source, in particular an EUV radiation source. A lithography projection exposure device comprises an illumination optical unit according to claim 12 and a projection optical unit for projecting a magnification mask arranged in an object field into an image field. A method for manufacturing a microelectromechanical device (110, 210, 310) preferably according to any one of claims 1 to 11, comprising a carrier substrate (100) and a plurality of MEMS modules (120, 220, 320), wherein each of the MEMS modules (120, 220, 320) comprises an ASIC layer (140) having an ASIC layer front side (140a) and an ASIC layer back side ( 140b), a baseboard (160, 360) having a baseboard front side (160a, 360a) and a baseboard back side (160b), and a plurality of micro-electromechanical components (130, 230, 330), wherein the baseboard (160, 360) is arranged on the ASIC layer front side (140a) and the baseboard back side (160b) is connected to the ASIC layer front side (140a), comprising the following steps: a.   Providing (410) a MEMS substrate having a structure of the base plate (160, 360) for the microelectromechanical component (130, 230, 330) and the plurality of MEMS modules (120, 220, 320); b.   Providing (420) an ASIC substrate having a structure of the ASIC layer (140) for the plurality of MEMS modules (120, 220, 320); c.   Manufacturing (430) a coupling substrate by connecting the MEMS substrate to the ASIC substrate, wherein a plurality of assigned electrical contact points (144) are formed between the MEMS substrate and the ASIC substrate for each of the plurality of MEMS modules (120, 220, 320); d. To obtain the plurality of MEMS modules (120, 220, 320), the coupling substrate is divided (440) along a predefined dividing line; e.   Providing (450) the carrier substrate (100); f.   Placing (460) the plurality of MEMS modules (120, 220, 320) on the substrate surface (100a) of the carrier substrate (100); and g.   The rear sides (140b) of the ASIC layers of the plurality of MEMS modules (120, 220, 320) are connected (470) to the substrate surface (100a) in a polymeric manner.

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