Glass monolithic membranes, double vertical membrane assemblies, micromachined spring structures and corresponding fabrication methods

Abstract

In order to broaden the application possibilities of micromachined bending structures 2 in glass, it is proposed to monolithically form vertical membranes 1 on the glass substrate 3, extending transversely to the substrate plane 5 of the glass substrate 3, by creating blind holes 8 by laser-induced modification of the glass substrate 3 and subsequent wet-chemical etching. This not only makes it possible to arrange the bending structure 2 inside the body 40 of the glass substrate 3, but also to form the spring structures 19 and solid joints 35 monolithically, in particular within the depth of the glass substrate 3. This also enables new actuation concepts in glass.

Description

[Technical Field]

[0001] The present invention relates to monolithic glass membranes. Such glass membranes may be configured, for example, as one- or two-sided suspended vertical membranes, or may be used as one- or two-sided suspended micromachined bending structures or, for example, one- or two-sided suspended displaceable spring beams. However, in addition to these micromachining applications, such monolithic glass vertical membranes can also be used for other applications, such as the assembly of sensors or actuators or microfluidic applications.

[0002] The present invention further relates to a double vertical membrane assembly having at least two opposing vertical membranes and a glass meander-shaped micromachined spring structure based thereon.

[0003] The invention also relates to the specific use of a monolithic membrane made of glass as described above.Finally, the invention further relates to a method for producing such a monolithic membrane from a glass substrate. [Background technology]

[0004] The reproducible production of extremely thin (less than 5 μm) membranes or bending elements is a major challenge with conventional methods and is associated with a lot of process engineering effort. Micromachined glass membranes as described at the beginning can be used in many applications, for example in the production of electronic components (for example high-performance capacitors), sensor technology (chemistry, biology or micromachining) or for example in microfluidics.

[0005] Furthermore, straight vertically oriented bent structures are often a robust and space-saving alternative to structures that can be displaced horizontally within the substrate plane in micromachining-type applications. However, fabricating truly vertical bent structures is often difficult with planar techniques (e.g., by conventional photolithography).

[0006] In the prior art, corrugated membranes, ie membranes with variable thickness, are already used in many products, in particular loudspeakers, to increase mechanical flexibility.

[0007] Furthermore, thin membranes or spring / bending elements are among the most important "building blocks" of microsystems technology. For example, in the field of MEMS (microelectromechanical systems), there are a range of approaches to reinforce membranes, often by deposited materials, which allow precise tuning of their bending properties. Summary of the Invention [Problem to be solved by the invention]

[0008] Against this background, the object of the present invention is to enable improved fabrication of glass micromachined membranes, which should further open up new application possibilities for glass membranes. [Means for solving the problem]

[0009] To achieve this object, the present invention provides a monolithic membrane made of glass with the features of claim 1. In particular, the present invention therefore provides for the object to be achieved by providing a monolithic membrane of the type described in the introduction, in which the membrane is exposed from the glass substrate by laser-induced modification of the glass substrate and subsequent wet-chemical etching, and the membrane is configured as a vertical membrane, whereby the plane of the vertical membrane extends transversely, i.e. in particular obliquely, to the substrate plane of the glass substrate.

[0010] In other words, the present invention proposes to monolithically form vertical films on a glass substrate using the so-called LIDE (laser induced deep etching) method. If the horizontal direction extends in the substrate plane of the glass substrate (which in the case of a typical glass wafer can be, for example, its surface), the vertical films pre-extend in the vertical direction, i.e., in particular obliquely to the substrate plane. The vertical films therefore extend towards (more or less deeply into) the depth of the glass substrate.

[0011] Although the LIDE method can relatively easily fabricate horizontal membranes, i.e., membranes whose membrane plane coincides with the substrate plane and whose main displacement direction is perpendicular to the substrate plane, such membranes often have relatively high non-uniformity with respect to their mechanical properties and are therefore difficult to control with respect to the reproducibility of membrane vibration or membrane displacement. Furthermore, horizontal membranes often require a large substrate area, which adversely affects the "footprint" of the microsystems thus fabricated. A further problem is that horizontal membranes are typically on or within the substrate surface and are therefore susceptible to external mechanical influences.

[0012] The approach according to the invention allows vertical membranes to be reproducibly produced with thicknesses (in the plane of the substrate) of less than 5 μm and thickness tolerances of less than 1 μm, and for various thicknesses of the glass substrates used (between approximately 50 μm and 1000 μm). This also allows the mechanical properties of the vertical membranes to be reproducibly adjusted, which allows them to be used, in particular, as micromachined bending elements. Furthermore, the bending structures realized by the vertical membranes according to the invention exhibit extremely high flexibility and fracture strength and can therefore withstand large displacements. Furthermore, some of the above-mentioned disadvantages of horizontal membranes are avoided.

[0013] The vertical membranes proposed herein are of great interest for micromachining-type applications and are therefore understood to be configurable with minute dimensions, where the thickness of the glass substrate may be, for example, between 50 μm and more than 1 mm, where the dimensions of the vertical membrane transverse to its longitudinal axis may be a few mm, more than 1 cm, or even a few cm, depending on the case.

[0014] The LIDE method belongs to the prior art and is known, for example, from the patent document EP 2 964 417. To date, this method has frequently been used to etch structures into glass substrates that form the housing of sensors, for example. The present invention therefore also addresses how the application of the LIDE method can be extended.

[0015] In the LIDE method, a material change (modification) is introduced into the bulk glass, typically by a single laser pulse across the entire thickness of the glass substrate, which allows a subsequent wet-chemical etching step to anisotropically etch such optically laser-prepared / exposed structures into the glass substrate, although the etching solution actually exhibits isotropic etching properties in the glass substrate. This technique allows, for example, to produce high-quality continuous vias in glass, which are interesting for hermetic assembly and connection technologies (AVT or hermetic packaging).

[0016] Furthermore, the LIDE method uses a pulsed laser, and with each laser shot (one laser pulse), the glass is modified along the z-direction (=optical axis / surface normal of the glass substrate). In this case, typically, no changes in the beam profile are applied. Therefore, in the LIDE method, individual small volumes (voxels) within the glass volume are not processed differently by the laser, as in other laser-based (e.g., ablation) glass processing methods.

[0017] According to the invention, this problem can also be solved by further advantageous embodiments according to the dependent claims.

[0018] For example, it is conceivable that at least one surface of the vertical film (which surface may extend in particular transversely to the main displacement direction of the vertical film) is defined by a blind hole produced by laser-induced modification of the glass substrate and subsequent wet-chemical etching. In this case, the blind hole may preferably have a non-circular cross section. That is, it is conceivable, for example, that the blind hole is longer transversely to the main displacement direction of the vertical film than it is deeper in the direction normal to the surface of the glass substrate.

[0019] The vertical membrane according to the present invention may preferably be defined by two blind holes laterally offset from one another, in particular facing opposite directions. In this case, both blind holes may form monolithic hole bases connected to the vertical membrane, in particular to the upper and lower ends of the vertical membrane, respectively. In this case, these and all blind holes described below may be / have been produced using the same wet chemical process as the vertical membrane, i.e., the LIDE method. Therefore, it is preferred if both blind holes are produced in the glass substrate by laser-induced modification of the glass substrate, in particular from two sides, followed by a common wet chemical etching.

[0020] The aforementioned two blind holes may have respective hole depths that differ from each other by, for example, less than 5%. Therefore, in this case, the blind holes are substantially the same depth. In such a case, the geometric center of gravity of the vertical film can be positioned approximately on the central plane of the glass substrate. This is advantageous, for example, for centering the solid joint, which will be described more precisely, on the glass substrate.

[0021] On the other hand, if it is desired that such a solid joint be positioned eccentrically relative to the central plane, the blind holes may have respective hole depths that differ significantly from each other, i.e., by more than 20%, particularly more than 50%, from each other. In other words, in such a case, the geometric center of gravity of the vertical film may be positioned eccentrically relative to the central plane of the glass substrate. Therefore, by changing the respective hole depths, the position of the vertical film along the surface normal of the glass substrate can be precisely adjusted. For example, the first vertical film may be positioned near the upper surface of the glass substrate, while the second vertical film may be positioned near the lower surface of the glass substrate.

[0022] When blind holes are used, it is also conceivable that two opposite surfaces of the vertical film are each bounded by a corresponding blind hole, preferably extending parallel to the longitudinal axis of the vertical film and / or at the same taper angle relative to the surface normal of the glass substrate, and here too it is conceivable that both blind holes are configured with opposite extension directions.

[0023] The blind hole or the plurality of blind holes may each have at least one hole wall extending at a taper angle relative to the surface normal of the glass substrate. In this case, the taper angle may be, in particular, greater than 1.0° or even greater than 1.5°. This allows the vertical film to extend obliquely relative to the substrate plane. This, in particular, allows the length of the vertical film to be geometrically increased, which is advantageous for achieving large displacements. The LIDE method also allows the cross-sectional area of ​​each blind hole in a vertical plane transverse to the substrate plane of the glass substrate to decrease toward the corresponding hole bottom. Such a configuration is particularly advantageous for enabling large displacements of a rotating body monolithically connected to the vertical film.

[0024] As will be further apparent from the drawings, the bottom of the blind hole may be defined by an outer surface of the glass substrate, that is, in particular by the top or bottom surface of the glass substrate.

[0025] The longitudinal axis of the vertical film may extend transversely, i.e., inclined, relative to the substrate plane of the glass substrate. This longitudinal axis may be visible, for example, in an x-z ​​cross section, penetrating the film when the x-y plane is taken as the substrate plane. In this case, the longitudinal axis may extend at a predetermined taper angle relative to the surface normal of the glass substrate (=normal to the substrate plane). In this case, the taper angle can be determined by the anisotropy of wet-chemical etching of the laser-induced modified region of the glass substrate. In this case, the hole walls of both blind holes may each form a taper angle relative to the surface normal. In other words, both blind holes may be formed with the same cross-sectional shape.

[0026] At least one of the bottoms of each blind hole, but preferably all of them, may exhibit a rounding at the center of the corresponding blind hole, which is obtained by wet-chemical isotropic etching. This is advantageous for avoiding peaks in mechanical stress in the region of the bottom of the hole, thereby improving the mechanical load-bearing capacity of the vertical membrane. In this case, in particular, the radius of curvature of the rounding can be predetermined by the etching radius of the isotropic etching. In this case, to form the rounding, the hole depth of each blind hole is preferably extended by wet-chemical over-etching beyond the modification depth of the modified region (laser-induced modification before etching) corresponding to the blind hole, so that the hole depth is greater than the modification depth of the corresponding modified region.

[0027] The main displacement direction of the vertical membrane may extend transversely, i.e., in particular parallel to, the substrate plane, i.e., the vertical membrane may have its greatest deflection transversely, in particular parallel to, the substrate plane.

[0028] According to one embodiment, it is provided that at least one lateral edge of the vertical membrane is made freestanding, so that it can be made to vibrate upon corresponding mechanical excitation.

[0029] To achieve this, a double vertical membrane assembly is also proposed, which has at least two opposing vertical membranes, each configured as described above or according to any one of the claims directed to a vertical membrane. In this case, both vertical membranes are connected to each other via a free-standing bridge monolithically defined or formed in the glass substrate by a (particularly central) blind hole. In this case, the (central) blind hole preferably defines one inner surface of each of both vertical membranes. In this case, each outer surface of both vertical membranes may be defined by one outer blind hole. In this case, the central blind hole preferably extends opposite both outer blind holes. In this case, both inner surfaces of both directly opposing vertical membranes may be directly opposite each other, so that only one cavity of the central blind hole exists between both vertical membranes. Furthermore, at least one of the outer blind holes may be defined on one side by the (unprocessed) bulk of the glass substrate.

[0030] In such double vertical membrane assemblies, as will become clear from the examples, this advantageously allows the implementation of high-precision micromachined actuator technology, in particular by means of one or more such double vertical membrane assemblies monolithic spring elements, bending and torsion elements and solid joints, in particular rotary joints.

[0031] A double vertical membrane assembly may, for example, have a number of vertical membranes aligned longitudinally, each facing the other. This allows for the creation of a monolithic spring structure. In this case, the spring structure may be reversibly deformable along the longitudinal direction and / or torsionally deformable about the longitudinal direction, depending on the design and / or number of the vertical membranes. That is, the spring structure may function as a linear spring and / or a torsion spring.

[0032] Therefore, in particular, a glass vertical membrane as described or claimed above is proposed, in particular as part of the double vertical membrane assembly just described, and in particular as part of the glass linear or torsion spring described above.

[0033] In such a double vertical membrane assembly, it is also conceivable according to the invention that both vertical membranes are configured symmetrically about a central axis, which preferably coincides with the surface normal of the glass substrate. This may be, for example, such that the free-standing bridge connecting both vertical membranes to one another is displaceable parallel to the substrate plane, despite the longitudinal axes of both bending structures forming an angle with respect to one another.

[0034] Furthermore, the double vertical membrane assembly may be monolithically connected to the glass substrate on both sides (ie, left and right sides) via the hole bottoms of each of the outer blind holes.

[0035] As shown in a further example, a configuration is also possible in which two continuous vertical membranes are connected by hole bottoms defined above and below each blind hole.

[0036] To this end, an alternative configuration is envisaged in which the double vertical membrane assembly is monolithically connected to the glass substrate only on one side via the bottom of the outer blind hole. This may be advantageous, for example, to form a free-standing end of the assembly, which may be displaceable out of the substrate plane and / or in the longitudinal direction of the double vertical membrane assembly and / or in rotation about the longitudinal direction.

[0037] A versatile glass meander-shaped micromachined spring structure can be obtained by using at least three mutually connected vertical membranes according to the invention (the vertical membranes may be configured as described above or as claimed herein) and / or by using at least two mutually connected double vertical membrane assemblies as described above. In this case, it is conceivable that at least one central vertical membrane of the spring structure is monolithically connected on the left and right sides to the free-standing bridges of each of the at least two double vertical membrane assemblies. Furthermore, the outer vertical membranes on the right and / or left sides can be monolithically connected to the hole bottoms of outer blind holes defined on one side by the bulk of the glass substrate (respectively). This opens up numerous possibilities for using the vertical membranes according to the invention in microactuator and microsensor technology.

[0038] To solve the problem, a specific use of a vertical glass membrane is also proposed, where the vertical membrane is configured as described above or according to one of the claims directed to the glass membrane. In this case, this use envisages using the vertical membrane to form a monolithic solid joint made of glass. For the same purpose, a double vertical membrane assembly according to the invention, as described above, can also be used.

[0039] Such a monolithic solid joint made of glass may be configured to allow rotation about a rotation axis oriented transversely to the longitudinal axis of the vertical membrane (and thus transversely to the surface normal of the glass substrate). This enables entirely new types of applications, and the monolithic design of the solid joint allows for highly reliable rotational movement. In particular, no play, as is often the case when using bearings, occurs. Furthermore, the monolithic realization allows for extreme miniaturization, as is known from conventional planar MEMS approaches, with the difference that the solid joint can be fabricated within the depth of the substrate. Thus, such a solid joint according to the invention can be characterized, for example, by its rotation axis extending through a depth of the glass substrate that is at least 10%, 20%, or even 30% of the thickness of the glass substrate. For better understanding, it is reiterated that the aforementioned rotation axis of the solid joint may extend parallel to the substrate plane but away from the upper and / or lower surface of the glass substrate.

[0040] In such a use, the two aforementioned solid joints can also be monolithically formed on the glass substrate by the vertical film according to the present invention. By arranging the two solid joints inside the glass substrate in this manner, it is possible to rotate the suspended rotating body at both solid joints relative to the glass substrate and out of the substrate plane of the glass substrate. In this case, the suspension of the rotating body is preferably realized monolithically, i.e., the rotating body itself can also be fabricated from the glass substrate by the LIDE method. However, it is also possible to form the rotating body separately and then connect it (at least indirectly) to the monolithically formed solid joint by a suitable connection technique (e.g., gluing or bonding) and thus mechanically suspend it therefrom.

[0041] For this reason, in the above-described use of two solid joints according to the present invention, the rotation axes of the solid joints may be configured to be parallel, since this allows a purely rotational movement of the rotating body without any other twisting. Furthermore, it is conceivable that the connecting line connecting both rotation axes (and preferably perpendicular to each rotation axis) forms an angle with respect to the substrate plane of the glass substrate. This is the case, for example, when both solid joints, or more precisely their rotation axes, are formed at different depths in the glass substrate (for example, relative to the upper surface of the glass substrate).

[0042] In a further attractive application of the proposed invention, that is, one that can be realized by the vertical membrane according to the invention, it is envisaged that the translator is or is suspended on the left and right sides of the glass substrate by two such solid joints, respectively. This approach makes it possible to convert a movement of the glass substrate in the substrate plane (caused, for example, by compression of the glass substrate, in particular by pressure on the substrate edges, or by decompression / expansion of the glass substrate, in particular by tension at the substrate edges) into a uniform, preferably rotation-free, up-and-down movement of the translator along the surface normal of the glass substrate by means of four solid joints (which create a connection to the translator). This makes it possible, in particular, to move the translator linearly out of the substrate plane, in particular with a stepless / uniform / continuous translation. Such a use is possible in particular if the translation bodies are each connected to the glass substrate via the respective rotation bodies (as described above), which connections may preferably likewise be constructed monolithically, i.e. both the translation bodies and the rotation bodies are each monolithically manufactured from the glass substrate by the LIDE method.

[0043] Furthermore, the present invention provides the features of the independent method claims to solve the problem described above. Therefore, in particular, to solve the problem of the method described above, the present invention proposes that at least one blind hole is created in the glass substrate by laser-induced modification of the glass substrate and subsequent wet-chemical etching, preferably highly anisotropic etching, to expose the vertical film, so that the at least one blind hole forms a monolithic hole bottom. In such an approach, it is advantageous if the at least one blind hole defines a surface of the vertical film, which surface extends, for example, transversely to the substrate plane of the glass substrate and / or transversely to the main displacement direction of the vertical film and / or predetermines the longitudinal direction of the vertical film.

[0044] However, instead of or in addition to the aforementioned features, the method for solving the problem described at the beginning can also be envisaged in which two oppositely oriented and laterally offset blind holes are created in the glass substrate by laser-induced modification of the glass substrate and subsequent wet-chemical etching to expose the vertical film. Such an approach can result in, in particular, the longitudinal axis of the vertical film extending in the direction of the hole wall of each of both blind holes. Furthermore, in this case, the hole walls can extend at respective, preferably identical, taper angles relative to the surface normal of the glass substrate, so that the vertical film exhibits a constant thickness.

[0045] Furthermore, the above-described method can be envisioned in which at least one blind hole is created in the glass substrate by wet-chemical anisotropic etching of the corresponding modified region. In this case, it is preferable to subsequently perform isotropic etching of the unmodified region to form a rounded center at the bottom of each blind hole. For example, over-etching can be performed to extend the hole depth of each blind hole beyond the modification depth of the corresponding modified region that was laser-induced modified before etching. As a result, the radius of curvature of the rounded center can correspond to the etching radius of the isotropic etching.

[0046] Furthermore, depending on the process sequence, it is conceivable to expose the vertical film by wet-chemical etching from both sides of the glass substrate. This is advantageous for enabling efficient production. In this case, it is preferable to modify the glass substrate before wet-chemical etching with laser pulses introduced into the glass substrate from two sides, i.e., in opposite directions. In this case, the same laser profile and / or the same Z-focus position (of the laser) can be used. Furthermore, it is preferable to use the same laser source and rotate the glass substrate between the two exposure steps. In this case, to enable accurate alignment of the blind holes with respect to each other, the second introduction of laser pulses from the lower side of the glass substrate (= second exposure step) can be performed based on at least one alignment structure previously created by the first introduction of laser pulses from the upper side of the glass substrate (= first exposure step). Here, the terms upper side and lower side are understood to be interchangeable, since they can be defined differently.

[0047] That is, to form vertical films, at least two opposing blind holes in the glass substrate can be created as a laser-induced modification in the glass substrate. This can be done by exposing the glass substrate to a laser from two sides, i.e., in particular, by a two-stage exposure process. The blind holes can then be etched in a common wet-chemical etching step. [Brief explanation of the drawings]

[0048] [Figure 1] 1 is a first example of a vertical membrane that is part of a double vertical membrane assembly constructed in accordance with the present invention. [Figure 2] 1 shows a meander-shaped micromachined glass spring structure monolithically suspended on both sides, obtained by juxtaposing multiple vertical membranes constructed according to the invention. [Figure 3]10A-10C are further examples of double vertical membrane assemblies and glass micromachined spring structures with multiple vertical membranes. [Figure 4] 1 is a micromachined glass spring structure exposed on one side based on a vertical membrane according to the present invention. [Figure 5] 1 is a further example of a micromachined spring structure using a vertical membrane according to the present invention. [Figure 6] 1 is a further example of a micromachined spring structure using a vertical membrane according to the present invention. [Figure 7] 1 is a further example of a micromachined spring structure using a vertical membrane according to the present invention. [Figure 8] A further example of how vertical membranes can be fabricated in a glass substrate to define multiple bending structures 2 in the form of spring beams. [Figure 9] A further example of how vertical membranes can be fabricated in a glass substrate to define multiple bending structures 2 in the form of spring beams. [Figure 10] A further example of how vertical membranes can be fabricated in a glass substrate to define multiple bending structures 2 in the form of spring beams. [Figure 11] 2 is a cross section of a meander-shaped micromachined spring structure based on a vertical membrane according to the present invention (corresponding to that of FIG. 1). [Figure 12] A spring structure similar to that of Figure 11, where the hole depth of the blind hole is reduced. [Figure 13] 10 is a further micromachined spring structure with vertical membranes exhibiting a relatively large spacing in the x-direction. [Figure 14] A spring structure similar to that of Figure 13, where the spatial frequency of the vertical membrane is increased by narrowing the width of the blind hole. [Figure 15] 1 illustrates the use of a vertical membrane according to the present invention to form two solid joints, thereby enabling rotation of a rotating body. [Figure 16]Assembly according to the invention from several vertical membranes making it possible to convert a movement in the plane of a glass substrate into a translational movement out of the plane of the substrate. [Figure 17] 1 illustrates various etching stages during wet chemical etching of blind holes by laser induced etching; [Figure 18] 4 is a further possible configuration of a spring structure according to the invention using a plurality of vertical membranes according to the invention. [Figure 19] 1 is an example of a spring structure according to the present invention that is embedded and disposed inside a glass substrate. [Figure 20] 1 is a scanning electron microscope image of a monolithic glass vertical membrane constructed in accordance with the present invention. [Figure 21] 1 is a scanning electron microscope image of a monolithic glass vertical membrane constructed in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0049] 1 shows a cross section of a glass substrate 3 along the x-z plane, with its top surface 17 defining the substrate plane 5 (x-y plane). Each laser pulse 27 was used to introduce a material change (modification) into the glass body 40 of the glass substrate 3, as indicated by the hatched area showing the modified region 22 within the glass substrate 3. To this end, the glass substrate 3 was exposed to a laser from both the top surface 17 and subsequently from the bottom surface 18 in a two-step exposure process. Thus, as illustrated by the block arrows in FIG. 1 , laser pulses 27 were introduced into the glass substrate 3 in opposite directions to introduce each laser-induced modification into the glass substrate 3.

[0050] As can also be seen from FIG. 1 , each modified region 22 was thereby produced by each laser pulse 27 to a modification depth 26 measured from each outer surface 10 of the glass substrate 3. The modified regions 22 were then exposed in a common wet-chemical etching process, which initially resulted in blind holes 8 a, 8 b, and 8 c. Due to the introduced modifications, the wet-chemical (actually isotropic) etching of the modified regions 22 proceeded significantly faster than in the unmodified regions 23 of the glass substrate 3, resulting in highly anisotropic etching. This laser-induced etching method can be summarized under the term LIDE (=laser-induced deep etching).

[0051] 1, a strong overetching was performed to form a respective radius 25 at the center of each hole bottom 9 of each blind hole 8a, 8b, 8c, thereby isotropically etching the unmodified region 23 of the glass substrate 3. This can be seen, for example, in FIG. 1, from the fact that the width of each of the blind holes 8 at the bottom end is greater than the width of the corresponding modified region 22, measured in the x-direction.

[0052] In this case, the individual stages during laser-induced etching are illustrated in Figure 17: (a) laser-modified area 22; (b) wet-chemical etching; (c) etching to modification depth 26; (d) slight over-etching (etching depth exceeds modification depth 26); (e) strong over-etching (thus forming a rounding 25 similar to that schematically suggested in Figure 1).

[0053] This over-etching therefore results in, in particular, each hole depth 24 of each blind hole 8 being greater than the corresponding modified depth 26 (see FIG. 1). The result of the over-etching can also be clearly seen in the left-hand detail of FIG. 8, where it can be seen that the radius of curvature of the rounding 25 corresponds to the etching radius 37 of the isotropic etching.

[0054] As a result, in the example of FIG. 1 , two films 1 were exposed from the illustrated glass substrate 3 by laser-induced modification of the illustrated glass substrate 3 followed by wet-chemical etching. The plane of each film 1 extends transversely to the substrate plane 5 of the glass substrate 3, thus forming a monolithic vertical film 1 on the glass substrate 3. As indicated by the horizontal block arrow in FIG. 1 , the main displacement direction 6 of the vertical film 1 extends transversely to the surface normal 13 of the glass substrate 3. In this case, both surfaces 7 a and 7 b defining or defining the left vertical film 1 and extending transversely to the main displacement direction 6 are delimited by blind holes 8 a and 8 b, respectively. More precisely, both the left vertical film 1 and the right vertical film 1 are delimited by two laterally offset, oppositely oriented blind holes 8 (left side: 8 a and 8 b, right side: 8 b and 8 c).

[0055] Thus, the main displacement direction 6 of the vertical film 1 extends parallel to the substrate plane 5 (or perpendicular to the taper angle 15) and not laterally relative to the substrate plane 5, as in the case of a typical horizontally extending film. The vertical film 1 has its largest displacement laterally relative to the substrate plane 5 because the vertical film 1 is significantly more extended in the y and z directions than in the x direction. In the example of FIG. 1 , both vertical films 1 have respective thicknesses in the x direction of less than 30 μm, which may even be, for example, less than 10 μm. In contrast, the dimension of each vertical film 1 in the y direction may be several hundred μm or even greater than 1 mm, for example, up to 1 cm or even up to several cm. As can be seen from FIG. 1 , in the z direction, the length of the vertical film 1 may be on the same order of magnitude as the thickness of the glass substrate 3.

[0056] In this case, each of the blind holes 8a, 8b, and 8c shown in FIG. 1 forms a monolithic hole bottom 9 connected to the respective vertical film 1. For example, the right-side film 1, whose right side is defined by the blind hole 8c, is monolithically connected at its upper end to the glass substrate 3 via the hole bottom 9. In this case, each hole bottom 9 is defined by the outer surface 10 of the upper or lower part of the glass substrate 3. However, this does not necessarily have to be the case. For example, it would be possible to make the hole depth 26 of each blind hole 8 only half the substrate thickness and simultaneously create a further blind hole 8 from the opposite side at the same position (i.e., with no or only a slight lateral offset in the x and y directions). In this case, the resulting hole bottom 9 would be located within the depth of the glass substrate 3 and therefore would not be defined by the outer surface 10 of the glass substrate, as shown in FIG. 18. Therefore, by creating modified regions 22 above and below the defined hole bottom 9 of each blind hole 8, the hole bottom 9 can be positioned within the depth of the glass substrate 3, as also shown in the example of Figure 19.

[0057] In the example of Fig. 1, the three blind holes 8a, 8b, and 8c are each configured with the same hole depth 24 (measured from each outer surface 10), except for slight process variations. As a result, the geometric center of gravity 32 of each vertical film 1 is approximately in the central plane 33 of the glass substrate 3, as shown in Fig. 11 for a similar case. However, this also applies to, for example, the four vertical films 1 in the example of Fig. 19. In contrast, the example of Fig. 18 shows that a configuration is also possible in which the geometric center of gravity 32 of each vertical film 1 is positioned offset (upward or downward) with respect to the central plane 33 of the glass substrate 3.

[0058] 15 shows an example of a vertical film 1 according to the present invention, defined by two oppositely extending blind holes 8a and 8b, each having a respective hole depth 24 that differs by more than 50%. Because the lower blind hole 8a is kept very short, the left vertical film 1 is positioned relatively close to the lower surface 18 of the glass substrate 3, so that the geometric center of gravity 32 of this vertical film 1 is positioned eccentrically relative to the central plane 33 shown. In this case, the center of gravity 32 of the vertical film 1 has a distance to the lower surface 18 that is less than 25% of the substrate thickness (i.e., the center of gravity 32 is in the lower quarter of the glass substrate 3).

[0059] 1 also clearly shows that both opposing surfaces 7a and 7b of the left vertical film 1 extend axially parallel, i.e., along the illustrated longitudinal axis 4a of the left vertical film 1. In this case, both surfaces 7a and 7b each form a taper angle 15 with respect to the surface normal 13 of the glass substrate 3.

[0060] When viewed from a different viewing angle, each of the blind holes 8a, 8b, and 8c shown in FIG. 1 has at least one hole wall 12 (see, for example, hole walls 12a and 12b) that extends at a taper angle 15 relative to a surface normal 13. In this case, the taper angle is greater than 1.5° in the example of FIG. 1. Furthermore, it is clearly visible that the cross-sectional area of ​​each of the blind holes 8 in the illustrated x-z vertical plane (i.e., transverse to the substrate plane 5) decreases in the direction toward each corresponding hole bottom 9. For example, in central blind hole 8b, the hole walls 12 defined by surfaces 7b and 7c converge toward each other, thereby confirming that the width of blind hole 8b in the x-direction decreases with increasing z-depth. In this case, as will become even more apparent in the examples below, each blind hole 8 (e.g., all blind holes in Figure 1) can be configured to be longer transversely to the main displacement direction 6, i.e., in the y direction in Figure 1, than the depth of each blind hole 8 in the direction of the surface normal 13 (i.e., in the z direction in Figure 1). That is, when looking at the xy plane 5 from above, it will be seen that the blind holes 8b have a non-circular cross section transversely to their z longitudinal direction.

[0061] 1 also clearly shows that the longitudinal axis 4 of the vertical film 1 extends obliquely, i.e. transversely, to the xy substrate plane 5, and that the longitudinal axis 4 forms a taper angle 15 with respect to the surface normal 13. In this case, the taper angle 15 results from the fact that, due to the laser-induced modification, wet-chemical etching proceeds highly anisotropically in the modified region 22, whereby etching proceeds there significantly faster in the z direction than in the x and y directions.

[0062] 1 further confirms that the three blind holes 8a, 8b, and 8c are each configured with the same cross-sectional shape with respect to the xz plane, and that in this case, all of these blind holes 8 were previously produced by a common wet-chemical etching process using uniform laser pulses 27, so that each hole wall 12 always forms a taper angle 15 with respect to the surface normal 13.

[0063] Furthermore, all of the hole bottoms 9 shown in FIG. 1 exhibit a uniform rounding 25 in the center of each blind hole 8, which rounding 25 was achieved by wet chemical isotropic overetching (i.e., beyond the modification depth 26 of the modified region 22) as previously described.

[0064] The configuration shown in FIG. 1 can also be interpreted as a double vertical membrane assembly 16, since the opposing vertical membranes 1, each extending axially symmetrically about the illustrated central axis 14, are connected to one another via a freestanding (monolithic) bridge 11. This bridge 11 is formed by the hole base 9 of the central blind hole 8b, which is therefore monolithically formed in the glass substrate 3 and is defined by the central blind hole 8b. In this case, the central blind hole 8b defines both the right surface 7B of the left membrane 1 and the left surface 7c of the right membrane 1. Furthermore, the central blind hole 8b extends opposite both outer blind holes 8a and 8c, which are in turn defined on one side by the body 40 of the glass substrate 3.

[0065] In this case, as can be seen in FIG. 1, the illustrated central axis 14 exactly coincides with the surface normal 13 of the glass substrate 3. Therefore, although the illustrated longitudinal axes 4a and 4b of both vertical membranes 1 form an angle with each other (this angle corresponds to exactly twice the taper angle 15), the bridge 11 also extends parallel to the substrate plane 5 and is therefore displaceable in the substrate plane 5. Therefore, both vertical membranes 1 shown in FIG. 1 can be functionally utilized as bending elements 2 to enable a translational shift of the bridge 11 in the z-direction or a rotational movement in the xz-plane. When observed from another viewing angle, the double vertical membrane assembly 16 can be compressed in the x-direction, and the right side of the glass substrate 3 moves toward the left side of the glass substrate 3 in the opposite direction to the x-direction.

[0066] 2 shows a further example of a similar double vertical membrane assembly 16 wet-chemically defined on a glass substrate 3 by the LIDE method, the assembly 16 comprising a number of opposing vertical membranes 1. In this case, the vertical membranes 1 are aligned along the illustrated longitudinal direction 31, thereby realizing a monolithic spring structure 19 that is reversibly deformable (compressible and expandable) along the longitudinal direction 31 (i.e., the x-direction in FIG. 2). In this case, the longitudinal direction 31 coincides with the main displacement direction 6 of each vertical membrane 1 of the assembly 16, respectively. However, the illustrated monolithic spring structure 19 can also be configured, for example, by dimensioning it accordingly, so that the spring structure 19 can be used as a torsion spring, and the spring structure 19 can be rotated about the y-axis or the x-axis.

[0067] In this case, in the example of FIG. 2, the first left-hand hole bottom 9 a is defined by the lower surface 18 of the glass substrate 3 , and the last right-hand hole bottom 9 b is defined by the upper surface 17 .

[0068] However, a configuration is also possible in which the left outer hole bottom 9 and the right outer hole bottom 9 are each defined by the same outer surface 10 of the glass substrate 3, as shown in FIG.

[0069] 2 and 3, the double vertical membrane assembly 16 is therefore monolithically connected to the glass substrate 3 on both sides via the bottom 9 of each of the outer blind holes 8. In contrast, in the example of FIG. 4, a laser pulse 27 is applied to the outer right edge of the assembly 16, resulting in a complete through-etching 30 of the glass substrate 3. As a result, the double vertical membrane assembly 16 is monolithically connected to the glass substrate 3 only on one side via the leftmost bottom 9, and therefore has a free-standing end 29 on the right side. This end 29 can be displaced both in the longitudinal direction 31 and out of the substrate plane 5.

[0070] The meander-like shape of each micromachined spring structure 19 shown in the examples of Figures 2-4 is achieved by the continuation of at least three vertical membranes 1 shown in Figure 1. Furthermore, in the illustrated examples, at least two double vertical membrane assemblies 16 are always contiguous with each other, as exemplarily shown in Figure 1, with bridges 11 alternately arranged on the upper and lower surfaces 17 and 18. Thus, in these examples, there is at least one central vertical membrane 20, which is connected to each of the freestanding bridges 11 on the left and right sides. For example, in Figure 2, it can be clearly seen that the outer vertical membrane 21 on the left side is monolithically connected by the hole bottom 9a of the outer blind hole 8a, which is defined on the left side, i.e., on one side, by the main body 40 of the glass substrate 3.

[0071] 5-7 illustrate various views of a further example of a micromachined spring structure 19 constructed in accordance with the present invention, which is monolithically constructed on a glass substrate 3 by juxtaposing a plurality of vertical membranes 1 according to the present invention. As can be seen in the top view of FIG. 6, each vertical membrane 1 has freely movable lateral ends 28 on the left and right sides, respectively.

[0072] If the right-hand portion of the glass substrate 3, designated by the reference number 38 in FIG. 7, is moved in the positive x-direction, the spring structure 19 will be compressed in the x-direction. Similarly, it is easy to imagine that if a load is applied to this rotating body 38 in the z-direction, the rotating body 38 can be rotated out of the xy-plane 5 (rotation about the y-axis). Therefore, the illustrated spring structure 19 can be used in particular as a monolithic solid joint 35. In this case, the rotation axis 36 shown in FIG. 7, which extends along the y-axis, indicates that the rotating body 38 can be rotated (approximately) about the y-axis by this solid joint 35. In this case, this rotation axis 36 is oriented transversely to the longitudinal axis 4 of the vertical membrane 1 (see FIG. 1) and also transversely to the surface normal 13 of the glass substrate 3. That is, if the rear end of the spring structure 19 is compressed somewhat more in the x-direction than the front end, a somewhat smaller rotation about the z-axis is also possible. By dimensioning the vertical membrane 1 accordingly, these rotational degrees of freedom can be adjusted.

[0073] 8-10 show a further example of how vertical films 1 according to the present invention can be fabricated on a glass substrate 3 by the LIDE method. Here, as in FIG. 1, the laser-modified regions 22 can be seen. Similarly, due to the translational movement, which also involves the wet-chemically produced rounding 25 of each hole bottom 9, the hole depth 24 of each blind hole 8 is somewhat deeper than the depth 26 of each modified region 22. This drawing should be understood as being schematic and not to scale. Furthermore, unlike the example of FIG. 6, FIG. 9 shows that the lateral edges 28 of each vertical film 1 are not freestanding but are each monolithically connected to the body 40 of the glass substrate 3. However, in this case, each vertical film 1 can still deform relative to the surrounding body 40 of the glass substrate 3, which can be utilized for various applications. For example, the hole bottom 9 shown in FIG. 10 can be displaced in the X direction (especially in the center).

[0074] 11-14 show further examples of how vertical films 1 can be configured according to the present invention. In this case, comparing FIGS. 11 and 12, for example, it can be seen that the spatial frequency of the vertical film 1 in the x-direction can be adjusted not only by adjusting the x-width of each blind hole 8 but also by adjusting the x-width of the hole bottom 9. Similarly, it can be seen that the expansion of each vertical film 1 in the z-direction can be varied by appropriately selecting the hole depth 24 of each blind hole 8. Such parameters can be controlled by the depth (modification depth 26) and / or width of the modified region 22, as well as by the etching time (see FIGS. 11 and 12). In both the configurations of FIGS. 11 and 12, each vertical film 1, or more precisely its geometric center of gravity 32, is located in the center of the glass substrate 3, i.e., on the central plane 33 shown in the figure.

[0075] Furthermore, by varying the anisotropy of the wet chemical etching process used to expose each vertical film 1, the taper angle 15 can also be adjusted, which can be clearly seen, for example, in a comparison of Figures 13 and 14. Here, it is again clearly seen that the spring structure 19 of Figure 14 has a significantly higher spatial frequency in the x-direction than the spring structure 19 of Figure 13. A further design parameter that can be varied is the ratio of the x-width of the blind hole 8 compared to the x-width of the corresponding hole bottom 9. This ratio substantially determines the thickness of each vertical film 1 in the x-direction.

[0076] FIG. 15 shows a further example in which a pair of vertical membranes 1 monolithically formed on a glass substrate 3 by the method according to the present invention defines two solid joints 35a, 35b within the depth of the glass substrate 3, from which a monolithic rotating body 38 is suspended. If the illustrated glass substrate 3 is stretched, for example, in the x-direction, the rotating body 38 rotates clockwise around the y-axis in the illustrated assembly, as indicated by the dashed arrow. To this end, both solid joints 35a and 35b, or more precisely, both geometric centers of gravity 32 of each vertical membrane 1, are arranged so that their respective rotation axes 36a and 36b (which in this example extend parallel to the y-direction) can be connected by a connecting line 37 that is angled with respect to the xy substrate plane 5. In the configuration of FIG. 15, this connecting line 37 also extends through the center of the glass substrate 3 in the z-dimension, i.e., through the center of the rotating body 38 in the x-position. Furthermore, based on the different hole depths 24 of both blind holes 8a and 8b in FIG. 15, it can be seen that the x-width of each hole bottom 9 also changes accordingly.

[0077] FIG. 16 illustrates a further example according to the present invention, in which a total of four vertical membranes 1 constructed according to the present invention (each monolithically fabricated on a glass substrate 3 by the LIDE method) are used to realize four solid joints 35a, 35b, 35c, and 35d. These solid joints 35a, 35b, 35c, and 35d allow the movement of the glass substrate 3 in the substrate plane 5 to be converted into a continuous up-and-down movement of a centrally located monolithic translator 39 in the direction of the surface normal 13, i.e., the z-direction in FIG. 16. For example, if the glass substrate 3 is stretched by a tensile load at the left and right ends, the central translator 39 shown can be moved linearly (in the z-direction shown) out of the substrate plane 5. As can be seen, for this purpose, the translator 39 is monolithically connected to the glass substrate 3 via respective rotators 38a and 38b. In this case, the rotating bodies 38a and 38b have opposite directions of rotation, which is achieved by constructing the solid joint 35 axially symmetrically about the illustrated central axis 14 (located in the center of the translating body 39).

[0078] As illustrated by the dashed circles in Figures 16 and 12, each solid joint 35 shown in Figure 16 could also be constructed by using multiple vertical membranes 1, i.e., micromachined spring structures 19 as shown in Figure 12 in particular.

[0079] The spring structure 19 of FIG. 18 differs from the spring structures of FIGS. 11-14 in that the individual hole bottoms 9 are not defined by the outer surface 10 of the glass substrate 3, but by blind holes 8 that face opposite each other. In other words, in the spring structure 19 of FIG. 18, two continuous vertical membranes 1 are connected by hole bottoms 9 defined above and below each blind hole 8. As can be seen from the three laser pulses 27 introduced from the bottom surface 18, this spring structure 19 is made possible in particular by the fact that the vertical membranes 1 of the illustrated double vertical membrane assembly 6 are defined by blind holes 8 that extend in the same direction, merge with each other, and have different hole depths 24. In this case, in the illustrated example, at least one combination of three blind holes extending in the same direction and merging with each other was introduced into the glass substrate 3 from the bottom surface 18 and the top surface 17 by LIDE.

[0080] The spring structure 19 of FIG. 19 is advantageously characterized in that each bridge 11 is located at a distance from the outer surface 10 of the glass substrate 3, i.e., within the depth of the glass substrate 3. This provides better protection for the spring structure 19 from mechanical influences. It should also be noted that the vertical films 1 are inclined significantly more strongly with respect to the surface normal 13 / z-axis (the taper angle 15 is greater than 10° in FIG. 19) than in the previous examples. This is achieved by using a wet-chemical etching solution with significantly lower anisotropy during etching of the vertical films 1 (for which the glass material must be selected accordingly), which allows etching to proceed more widely and increases the taper angle 15 and thus the inclination of each vertical film 1 with respect to the z-axis.

[0081] 20 and 21 show images of micromachined spring structures 19, taken with a scanning electron microscope, defined on the basis of vertical membranes 1 according to the invention by the LIDE method. On the one hand, it can be seen that each membrane 1 extends perpendicularly to the substrate plane 5 and has a thickness of several micrometers, while, for example, the hole bottoms 9 have a width of about 50 μm.

[0082] In summary, to broaden the application possibilities of micromachined bending structures 2 in glass, it is proposed to monolithically form vertical membranes 1 on a glass substrate 3, extending transversely to the substrate plane 5 of the glass substrate 3, by creating blind holes 8 by laser-induced modification of the glass substrate 3 and subsequent wet-chemical etching. This allows not only the bending structure 2 to be arranged inside the body 40 of the glass substrate 3, but also the spring structure 19 and the solid joints 35. This also enables novel actuation concepts in glass (see FIG. 5). [Explanation of symbols]

[0083] 1 Vertical membrane 2. Bending structures, especially spring beams 3. Glass substrate 4 (1) longitudinal axis 5. Substrate plane (3 flat surfaces) 6 (1) Principal Displacement Direction 7 (1) Surface 8 blind hole 9 (8) Bottom of the hole 10 (3) exterior 11 Bridge 12 (8) Hole Wall 13 (3) Surface Normals 14 Center axis 15 Taper angle 16 Double Vertical Membrane Assembly 17 (3) Top 18 (3) bottom 19 Spring structure 20 (of 19) central vertical membranes 21 (19) outer vertical membrane 22 (of 3) modified region (where modification in 3 is induced by laser / by adjusting the laser pulses, and this modification significantly enhances the wet chemical etching rate compared to other unmodified regions of 3) 23 (of 3) unmodified area (this area is located outside the introduced laser radiation) 24 (8 in z-direction) hole depth 25 (8 / 9 center) rounded 26 modification depth (= 22 depth in z direction of 3) 27 Laser Pulse 28 (1) Lateral end 29 (16 / 19) Freestanding forward end 30 Through etching 31 (16 / 19) longitudinal direction 32 (of 1) geometric center of gravity 33 (3) central plane 34 Linear spring 35 Solid Joint 36 (35) rotation axis 37 Etching Radius 38 Rotating Body 39 Translation field 40 3 body (English: bulk)

Claims

1. A monolithic membrane (1) made of glass, -especially, - as a vertical membrane (1) suspended on one or both sides, and / or - as a micromachined bending structure (2) suspended on one or both sides, in particular as a displaceable spring beam suspended on one or both sides The membrane (1) is configured as follows: - said membrane (1) is exposed from the glass substrate (3) by laser-induced modification of said glass substrate (3) followed by wet-chemical etching, - the film (1) is configured as a vertical film (1), whereby the plane of the vertical film (1) extends transversely to the substrate plane (5) of the glass substrate (3); A membrane (1).

2. At least one surface (7) of the vertical membrane (1), in particular extending transversely to the main displacement direction (6) of the vertical membrane (1), is defined by blind holes (8) produced by laser-induced modification of the glass substrate (3) and subsequent wet-chemical etching, - preferably, said blind hole (8) has a non-circular cross section, and / or the blind holes (8) are configured to be longer transversely to the main displacement direction (6) of the vertical membrane (1) than they are deeper in the direction of the surface normal (13) of the glass substrate (3); A vertical membrane (1) according to claim 1.

3. the vertical membrane (1) is defined by two blind holes (8a, 8b) laterally offset from one another, in particular facing oppositely, In particular, both of the blind holes (8a, 8b) form monolithic hole bottoms (9) connected to the vertical membrane (1), in particular to the upper and lower ends of the vertical membrane (1), respectively; Preferably, both blind holes (8a, 8b) are made in the glass substrate (3) by laser-induced modification of the glass substrate (3), in particular from two sides (17, 18), followed by a common wet-chemical etching; A vertical membrane (1) according to claim 1 or 2.

4. the blind holes (8a, 8b) have respective hole depths (24) that differ from each other by less than 5% and / or the geometric center of gravity (32) of the vertical film (1) is located approximately in the central plane (33) of the glass substrate (3), or the two blind holes (8a, 8b) have respective hole depths (24) that differ from each other by more than 20%, in particular by more than 50%, and / or the geometric center of gravity (32) of the vertical film (1) is arranged eccentrically with respect to the central plane (33) of the glass substrate (3), A vertical membrane (1) according to claim 3.

5. Preferably, two opposing surfaces (7a, 7b) of the vertical film (1), each extending parallel to the longitudinal axis (4) of the vertical film (1) and / or at the same taper angle (15) relative to the surface normal (13) of the glass substrate (3), are each bounded by a corresponding blind hole (8), - Preferably, both said blind holes (8) are configured with opposite directions of extension; A vertical membrane (1) according to any one of claims 1 to 4.

6. The blind hole (8) or the plurality of blind holes (8) each have at least one hole wall (12a, 12b) extending at a tapered angle (15) with respect to a surface normal (13) of the glass substrate (3); in particular, said taper angle (15) is greater than 1.0°, in particular greater than 1.5°, and / or the cross-sectional area of ​​each of the blind holes (8) in a vertical plane transverse to the substrate plane (5) of the glass substrate (3) decreases in the direction of each corresponding hole bottom (9); A vertical membrane (1) according to any one of claims 1 to 5.

7. The bottom (9) of each of the blind holes (8) is defined by the outer surface (10) of the glass substrate (3), in particular by the upper surface (17) or the lower surface (18) of the glass substrate (3). A vertical membrane (1) according to any one of claims 2 to 6.

8. the longitudinal axis (4) of the vertical film (1) extends transversely, in particular obliquely, to the substrate plane (5) of the glass substrate (3), - preferably, said longitudinal axis (4) extends at a predetermined taper angle (15) relative to the surface normal (13) of said glass substrate (3); In particular, the taper angle (15) is determined by the anisotropy of the wet-chemical etching of the laser-induced modified area (22) of the glass substrate (3), and / or the hole walls (12a, 12b) of each of the two blind holes (8a, 8b) respectively form the taper angle (15) with respect to the surface normal (13), in particular so that both blind holes (8a, 8b) are formed with the same cross-sectional shape; A vertical membrane (1) according to any one of claims 1 to 7.

9. at least one of said hole bottoms (9), but preferably all of said hole bottoms (9), exhibits a rounding (25) at the center of the corresponding blind hole (8), obtained by wet-chemical isotropic etching; in particular, the radius of curvature of said rounding is predetermined by the etching radius (37) of said isotropic etching, Preferably, for this purpose, the hole depth (24) of each of the blind holes (8) is extended by wet-chemical over-etching beyond the modification depth (26) of the modified area (22) corresponding to the blind hole (8) which has been laser-induced modified before said etching, so that the hole depth (24) is greater than the modification depth (26) of the corresponding modified area (22). A vertical membrane (1) according to any one of claims 1 to 8.

10. the main displacement direction (6) of the vertical membrane (1) extends transversely, in particular parallel to, the substrate plane (5), and / or - the vertical membrane (1) has its greatest deflection laterally, in particular parallel to the substrate plane (5); A vertical membrane (1) according to any one of claims 1 to 9.

11. At least one lateral edge (28) of the vertical membrane (1) is made free-standing, In particular, this allows the end (28) to vibrate upon corresponding mechanical excitation; A vertical membrane (1) according to any one of claims 1 to 10.

12. A double vertical membrane assembly (16) having at least two opposing vertical membranes (1), each constructed according to any one of claims 1 to 11, - both said vertical membranes (1) are connected to each other via a free-standing bridge (11) that is monolithically defined in the glass substrate (3) in particular by a central blind hole (8b), - preferably, said central blind hole (8b) defines one respective inner surface (7b, 7c) of each of said two vertical membranes (1); in particular, the outer surfaces (7a, 7d) of each of said two vertical membranes (1) are bounded by one outer blind hole (8a, 8b), - preferably, said central blind hole (8b) extends opposite both said outer blind holes (8a, 8c), and / or at least one of said outer blind holes (8a, 8b) is bounded on one side by the body (40) of said glass substrate (3); In particular, the double vertical membrane assembly (16) comprises a number of opposing vertical membranes (1) arranged along a longitudinal direction (31), preferably constituting a monolithic spring structure (19) that is reversibly deformable along the longitudinal direction (31); Dual vertical membrane assembly (16).

13. Both vertical membranes (1) are symmetrically arranged about a central axis (14), - preferably, said central axis (14) coincides with the surface normal (13) of said glass substrate (3); - in particular, the bridge (11) is displaceable parallel to the substrate plane (5), despite the longitudinal axes (4a, 4b) of both vertical membranes (1) forming an angle with respect to one another, and / or - two mutually continuous vertical membranes (1) connected by hole bottoms (9) defined above and below each blind hole (8); The dual vertical membrane assembly (16) of claim 12.

14. - the double vertical membrane assembly (16) is monolithically connected to the glass substrate (3) on both sides via the respective hole bottoms (9a, 9b) of the respective outer blind holes (8a, 8c), or - said double vertical membrane assembly (16) is monolithically connected to said glass substrate (3) only on one side via the hole bottoms (9) of the outer blind holes (8a, 8c), in particular thus forming a free-standing edge (29); In particular, said free-standing end (29) is displaceable out of the plane of the substrate (5) and / or in the longitudinal direction (31) of said double vertical membrane assembly (16); A double vertical membrane assembly (16) according to claim 12 or 13.

15. A meander-shaped micromachined spring structure (19) made of glass, said spring structure (19) comprising: - at least three mutually adjacent vertical membranes (1) according to any one of claims 1 to 11, and / or - at least two mutually adjacent double vertical membrane assemblies (16) according to any one of claims 12 to 14; It has - preferably, at least one central vertical membrane (1, 20) of said spring structure (19) is monolithically connected, on the left and right sides, respectively, to a free-standing bridge (11) of each of said at least two double vertical membrane assemblies (16); in particular, the right and / or left outer vertical membranes (1, 21) are monolithically connected to the hole bottoms (9) of the outer blind holes (8a, 8c) defined on one side by the body (40) of said glass substrate (3); Spring structure (19).

16. Use of a glass vertical membrane (1) according to any one of claims 1 to 11 or a double vertical membrane assembly (16) according to any one of claims 12 to 14 for forming a monolithic solid joint (35) made of glass, comprising: Preferably, said solid joint (35) allows rotation about a rotation axis (36) directed transversely to the longitudinal axis (4) of said vertical membrane (1) and transversely to the surface normal (13) of said glass substrate (3); use.

17. two such solid joints (35a, 35b) are each formed monolithically on the glass substrate (3) by at least one vertical membrane (1), so that in both said solid joints (35a, 35b) a rotating body (38), preferably monolithically suspended, can be rotated relative to said glass substrate (3) and out of the substrate plane (5) of said glass substrate (3); In particular, for this purpose, the rotation axes (36a, 36b) of each of the solid joints (35a, 35b) are configured parallel to each other, and / or - for this purpose, the connecting line (37) connecting both rotation axes (35a, 35b) is angled with respect to the substrate plane (5); 17. The use according to claim 16.

18. a translator (39) is suspended or suspended on the left and right sides of the glass substrate (3) by two such solid joints (35a, 35b and 35c, 35d), respectively, and a movement of the glass substrate (3) in the substrate plane (5) is converted by four of the solid joints (35a, 35b and 35c, 35d) into a uniform, preferably rotation-free, vertical movement of the translator (39) along the surface normal (13) of the glass substrate (3), - in particular by moving said translator (39) in a linear translational movement out of said substrate plane (5), and / or the translators (39) are connected, preferably monolithically, to the glass substrate (3) via respective rotators (38a, 38b); 18. Use according to claim 16 or 17.

19. A method for producing a monolithic vertical membrane (1), in particular a vertical membrane (1) according to any one of claims 1 to 11, from a glass substrate (3), comprising: - creating at least one blind hole (8a, 8b, 8c) in the glass substrate (3) by laser-induced modification of the glass substrate (3) followed by wet-chemical etching, preferably highly anisotropic etching, to expose the vertical membrane (1), whereby the at least one blind hole (8a, 8b, 8c) forms a monolithic hole bottom (9); Preferably, said at least one blind hole (8a, 8b, 8c) defines a surface (7a, 7b, 7c, 7d) of said vertical membrane (1), said surface (7a, 7b, 7c, 7d) being: - extending transversely to the substrate plane (5) of said glass substrate (3), and / or - extending transversely to the main displacement direction (6) of said vertical membrane (1), and / or - Predetermining the longitudinal direction (4) of the vertical membrane (2) A method characterized by:

20. - two oppositely oriented and laterally offset blind holes (8a, 8b) are created in the glass substrate (3) by laser-induced modification of the glass substrate (3) followed by wet-chemical etching, exposing the vertical membrane (1); in particular, such that the longitudinal axis (4) of said vertical membrane (1) extends in the direction of the hole walls (12a, 12b) of each of said two blind holes (8a, 8b); In particular, the hole walls (12a, 12b) extend at respective, preferably the same, taper angles (15) relative to the surface normal (13) of the glass substrate (3), so that the vertical film (1) exhibits a constant thickness.

20. The method according to the preamble of claim 19, in particular according to claim 19.

21. said at least one blind hole (8a, 8b, 8c) being produced in said glass substrate (3) by wet-chemical anisotropic etching of the corresponding modified area (22); - preferably followed by isotropic etching of the unmodified area (23) in order to form a central radius (25) at the bottom (9) of each of said at least one blind hole (8a, 8b, 8c); In particular, for this purpose, an over-etching is carried out, whereby the hole depth (24) of each of said blind holes (8) is extended beyond the modification depth (26) of the corresponding modified area (22) which has been laser-induced modified before said etching, and / or - the radius of curvature of said rounding (25) corresponds to the etching radius (37) of said isotropic etching; 21. The method of claim 19 or 20.

22. exposing the vertical film (1) by wet chemical etching from both sides (17, 18) of the glass substrate (3); - modifying the glass substrate (3) before the wet-chemical etching by means of laser pulses (27) which are preferably introduced into the glass substrate (3) starting from two sides (17, 18), i.e. in opposite directions, - in particular using the same laser profile and / or the same z-focus position, Particularly preferably, for this purpose, the same laser source is used and the glass substrate (3) is rotated between the two exposure steps, - a second introduction of a laser pulse (27) from the lower surface (18) of the glass substrate (3) based on at least one alignment structure previously created by a first introduction of a laser pulse (27) from the upper surface (17) of the glass substrate (3), 22. The method according to any one of claims 19 to 21.

23. At least two opposing blind holes (8a, 8b) in the glass substrate (3) for defining the vertical membrane (1), - producing in said glass substrate (3) as a laser-induced modification by exposing said glass substrate (3) from two sides by a laser, in particular by a two-stage exposure process, - then etched in a common wet chemical etching process, 23. The method according to any one of claims 19 to 22.

Images