Method of fabricating a micromechanical structure out of two-dimensional elements and micromechanical device

In a method of fabricating a micromechanical structure, first, a deflectably supported two-dimensional structure is formed in a substrate and, then, is arranged in a package such that an integrated micromanipulator is arranged between the package and the two-dimensional structure so as to effect a deflection of the two-dimensional structure out of a plane of the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. 102008012826.0, which was filed on Mar. 6, 2008 and German Patent Application No. 102007015722.5, which was filed on Apr. 2, 2007, which are both incorporated herein in their entirety by reference.

TECHNICAL FIELD

The present invention relates to the fabrication of micromechanical three-dimensional (3D) structures by means of mechanical pre-deflection of two-dimensional (2D) structures out of a wafer plane or substrate plane and subsequent possible fixation in the deflected state.

BACKGROUND

Such three-dimensional structures are employed in micro and microsystem technology and are used for the fabrication of electrostatic three-dimensional drive structures, for example. Such drives may be of interest for a multitude of microsystems, and specifically for microscanners for image projection. Such 3D structures may, for example, be utilized to realize an electrostatic drive capable of generating forces and moments out of a wafer plane across a large translation and/or rotation range.

Several ways of deflecting structures out of a wafer plane are known. Known methods utilize material stresses of a substrate material or a substrate-layer combination for warping the substrate at defined locations. The warping may then be utilized for tilting or rotating the structures out of the substrate. The material stress may be intrinsic in material pairings or may be impressed by means of a so-called actor. However, the curvatures of the substrate achievable by means of material stress are slight. In addition, there will be extensive space necessitatements on the substrate in order to build up the material stress and realize significant angles of attack of structures with respect to the substrate. Same may be enlarged by means of local down-thinning of the substrate, which may, however, weaken the mechanical stressability of the structure to be deflected and result in low-frequency oscillation modes.

SUMMARY

According to an embodiment, a method of fabricating a micromechanical structure may have the steps of: forming a deflectably supported two-dimensional structure in a substrate; and arranging the deflectably supported two-dimensional structure in a package such that an integrated micromanipulator is arranged between the package and the two-dimensional structure so as to effect a deflection of the two-dimensional structure out of a plane of the substrate.

According to another embodiment, a micromechanical device may have: a package; a substrate; a two-dimensional structure arranged in the substrate; and a micromanipulator arranged between the package and the two-dimensional structure such that the two-dimensional structure is deflected out of a plane of the substrate.

Embodiments of the invention show that the micromanipulator may be embodied as a permanent component of the device package. During the packaging of the micromechanical device, the pre-deflection or deflection of the deflectably supported two-dimensional structure and therefore the realization of a three-dimensional structure may be effected by means of the micromanipulator. After the realization of the three-dimensional structure, the micromanipulator may remain in the micromechanical device so that the three-dimensional deflection of the structure may already be permanently defined by the geometry as well as by the form and force closure with the micromanipulator.

In force and/or moment initiation via the micromanipulator, the device may, according to its support, rotate, tilt or shift out of the wafer plane. The deflected member or the three-dimensional structure may now be fixed. A fixing may be effected in a form-fit, force-fit or material-fit manner. As a form-fit fixing method, e.g. mechanical hooks or latches may be used which block and/or arrest the two-dimensional method in the deflected state. As a material-fit fixing method, e.g. adhering, bonding, soldering or connecting by alloying may be performed. The deflected two-dimensional elements may be fixed in a force-fit manner by the acting of adhesion forces, clamping forces and friction forces, for example. Following that, the two-dimensional element of the structured wafer plane forms a three-dimensional element.

The micromanipulator may be embodied as a micromechanically or precision mechanically fabricated structure and may be a permanent component of the packaged device. The micromanipulator may be in permanent engagement with the two-dimensional structure to be pre-deflected.

DETAILED DESCRIPTION

Referring toFIG. 1, the method for the fabrication of three-dimensional micromechanical devices from two-dimensional elements is discussed by means of the flowchart. The method comprises the forming100of a deflectably supported two-dimensional structure in a substrate and the arranging102of the deflectably supported two-dimensional structure in a package or in parts of a package structure (packaging). The package comprises an integrated micromanipulator so that, by means of a force action of the micromanipulator on the two-dimensional structure, a deflection of the two-dimensional structure out of the substrate plane so as to form the three-dimensional structure is performed. The micromanipulator may be part of the package, e.g. of the package cap, so that same, in fitting the cap, contacts the two-dimensional structure and deflects same. Alternatively, the micromanipulator may be part of the two-dimensional structure so that, for example in sealing the package, a cap contacts the manipulator and effects a deflection of the two-dimensional structure. The micromanipulator may also be a separate member which, after the insertion of the two-dimensional structure into a package, is also arranged in the package so that, in fitting the cap, the two-dimensional structure is deflected by the micromanipulator.

The formation of the deflectably supported two-dimensional structures in a substrate may be effected in a wafer, for example. That is, the three-dimensional elements or structures are first microtechnically fabricated as two-dimensional structures in the substrate plane. This allows for good fabricability of the structures. The two-dimensional structures are fabricated such that they are deflectable but retained in the substrate plane by means of dedicated fixed bearings, for example. The fixed bearings determine the structures' degree of freedom for the deflection out of the plane. The structures may at a suitable location be provided with mechanical contact pads, via which then, by means of a mechanical structure such as a mandrel, a pin, a needle, a mesa structure or any other means, a force or a moment may be introduced into the two-dimensional device in a defined manner. In the following, these structures will be referred to as micromanipulators or microactuators. A mesa structure may be an elevated, plateau-like semiconductor structure, the environment of which having been etched off. By means of this, the 2D structure may be pre-deflected out of the substrate plane, thereby producing a 3D structure.

The micromanipulator may be integrated as a permanent component of the device package or with parts of the package and thus utilized to exert, in packaging the micromechanical device, a force or a moment on the two-dimensional device in a defined manner so as to thereby deflect the two-dimensional structure, thereby forming the three-dimensional structure. After the realization of the three-dimensional structure by means of the micromanipulator, which may be a permanent component of the package, the micromanipulator may remain in permanent use in the micromechanical device so that the three-dimensional deflection of the structure is permanently defined already by the geometry as well as the form and force closure with the micromanipulator. What is also conceivable is that the deflected two-dimensional structure is fixed in the deflected position by other means. This fixing may be effected in a form-fit, friction-fit or material-fit manner.

The packaging of the micromechanical device may be effected at wafer level, whereby the number of simultaneously packaged micromechanical devices may be increased, or else in individual steps. It is also conceivable that the micromechanical devices are first diced and then installed in external packages made of metal, plastic, glass or ceramic, for example.

The following embodiment illustrates a microtechnically two-dimensionally fabricated and rotatably supported electrode structure on a wafer or an already diced chip and the fabrication of a three-dimensional structure such as a three-dimensional drive electrode by means of erecting this two-dimensional structure by means of a micromanipulator permanently connected to the package or the packaged microtechnical device during the packaging process. The manner is shown in which these two-dimensional structures may be deflected out of a plane and permanently fixed there by means of mechanical structures—the micromanipulators or microactuators—during the packaging. It is to be noted that the different ways of deflecting and fixing the two-dimensional structure may be combined with one another in great variety of ways, which is why not all ways are illustrated herein. Therefore, the embodiments shown are in no way any limitation of the inventive method and of the micromechanical devices having an integrated micromanipulator and being fabricated by means of the inventive method.

FIG. 2shows a top-view representation of a micromechanical one-dimensional scanner mirror11prior to packaging, wherein movable10and stationary12drive or comb electrodes will be located in the same substrate plane14of a two-dimensionally structured wafer after the micromechanical fabrication. The movable drive electrodes10are mounted, together with the scanner mirror15, to a rotatorily supported torsion axis20. The stationary electrodes12are also rotatorily supported on a torsion axis21via torsion springs16. By means of force initiation at the contact pads18by means of a micromanipulator, the stationary electrodes12may be deflected out of the substrate plane14, whereby they create a three-dimensional structure. The two-dimensional structure may, for example, be fabricated in the so-called Silicon-On-Insulator (SOI) technology and may be supported via fixed bearings19which remain on the underlying oxide layer22after etching the silicon substrate14.

FIG. 3shows an embodiment of the present invention by means of a cross-sectional representation of an already packaged one-dimensional scanner mirror according toFIG. 2. The cross-sectional representation runs perpendicular to the torsion axis20of the scanner mirror. The two-dimensional structure is tilted out of the wafer plane by means of a mechanical structure, the micromanipulator24, which attacks at the contact pads18(seeFIG. 1) of the tiltably supported stationary electrode structure12. Here, the micromanipulator structure24, which is utilized for the three-dimensional deflection and is in the following referred to as an activation structure or microactuator structure, is permanently connected to the device package22. The micromanipulator24may be connected to the cap structure26of the device package22. After aligning the optical cover glass26, the stationary drive electrode12is deflected by means of pressing the planar connecting rib18of the counter-electrodes12downwards. I.e., next to hermetically sealing the package, the optical cover glass26may also serve as a support for the micromanipulator. The rotation of the stationary electrodes12is effected with force action on the rotation axis by means of torsion springs16.

After pressing the cover glass down, same may permanently be connected to the microdevice to be packaged, in a direct or immediate manner via a frame structure30a, which serves as a spacer and may be utilized for realizing a cavity structure. Here, the connection between the micromechanical device14, the spacer30, the glass cover26and the bottom substrate28may be effected by means of e.g. adhering, wafer bonding, anodic or silicon direct-bonding, soldering, connecting by alloying, by means of Solid Liquid Inter Diffusion (SLID) or any other form-fit connection. The deflection of the two-dimensional structure is fixedly defined by the geometry, the placement and well as the fabrication and alignment tolerances of the micromanipulator.

Therefore, packaging may also be regarded as an alignment of a cover glass relative to the microdevice and the pressing-down of the cover glass by means of the integrated micromanipulator for hermetically sealing the package and for deflecting the 2D structure, for example. It is, however, also conceivable that the package is not hermetically sealed and the micromanipulator is permanently connected only to parts of a package structure, which may comprise a frame structure, a cover structure or a bottom structure, for example.

The packaging of the micromechanical device, in this embodiment of the micromirror, as well as the simultaneous pre-deflection of the two-dimensional structure for the realization of three-dimensional structures, may advantageously be effected in the wafer matrix so as to obtain high parallelism in the packaging of the devices and therefore enable lower fabrication cost. However, all the embodiments described above and below equally apply to the packaging and simultaneous deflection of a single micromechanical device.

It is conceivable that the contact pads in direct mechanical contact during the deflection of the two-dimensional structure are coated with additional wear-resistant or ductile materials so as to reduce stress and avoid the formation of particles. Here, both the contact pads of the two-dimensional structures to be deflected and the micromanipulator contact pads may be coated with additional no-wear materials. These materials may be e.g. oxides, nitrides, silicon nitride, carbide layers, diamond layers and/or ductile layers such as metals like gold, aluminum, aluminum alloys, nickel and other metals. However, they may also be polymers such as photoresist, polyamides, Teflon or other polymer materials.

Moreover, the contact pads of the micromanipulators employed for the deflection of the two-dimensional structures may be geometrically designed such that they exhibit, for the deflection angle to be realized of the two-dimensional structures to be deflected, a maximum contact pad that is aligned in parallel to the deflected two-dimensional structure.

The contact pad of the two-dimensional structure to be deflected may be configured such, by means of supporting the surface of force attack of the micromanipulator by means of additional spring elements, that the contact pad of the deflected two-dimensional structure may on its own initiative align in parallel to the contact pad of the attacking micromanipulator. This serves to achieve a contact pad as large as possible between the deflected two-dimensional structure and the attacking micromanipulator.

Furthermore, the deflection of the two-dimensional structure by means of the micromanipulator having been accomplished, their common contact may be permanently fixed by the use of material-fit, such as adhering, bonding, soldering, SLID, connecting by alloying or form-fit, such as mechanical latching, or force-fit connections. Force-fit connections may be achieved by e.g. adhesion, friction or clamping forces. The two-dimensional structures to be deflected by means of micromanipulators may be movably supported via torsion support, via parallel guide by respective joints, such as a four-hinged joint or else support via flexion springs, for example.

InFIG. 3, the movable electrode10tilted via the torsion axis20and the stationary electrodes12(AVC counter-electrodes) deflected via the two micromanipulators24(Angular Vertical Comb (AVC) activation structures) and via the torsion springs16are illustrated. The frame structure14with the integrated device is arranged between the cap structure26, a frame structure30aand a bottom-substrate structure28with the associated spacer30b.

InFIG. 4, a packaged micromechanical device with tilted two-dimensional structures pre-deflected downwards by means of micromanipulator structures is illustrated. Here, the micromanipulator structures24are permanently connected to an optical cover substrate26which, in the relevant wavelength range of electromagnetic radiation interacting with the scanner mirror15, exhibits a high transmission degree. The cover glass26may be permanently connected to the micromechanical device after packaging. Here, the cover glass may be connected either directly or indirectly via a frame or a spacer structure30a, which in turn may be comprised of several individual components. Optionally, the micromechanical device may be permanently sealed on its back side by means of a bottom substrate28and a frame structure30b.

FIG. 5shows an embodiment of a packaged micromechanical device9having tilted two-dimensional structures pre-deflected downwards by means of micromanipulator structures24. Again, the structures may, for example, be the above-mentioned scanner mirror with the respective electrodes12and the respective torsion axis20and/or the torsion springs16. The micromanipulator structure24may be permanently or monolithically connected with a support structure32. The support structure32itself need not exhibit any optical function, for example, and therefore need not be transparent, but it may, in the area of the optically effective surface of the micromechanical device9, have an aperture34for unobstructed optical coupling and decoupling. For micromechanical devices without any optical function, no aperture34is necessitated in the support structure32.

After packaging, the support structure is permanently connected to the micromechanical device. The support structure is connected either directly or indirectly via a frame spacer structure30a. Optionally, the micromechanical device may again be hermetically sealed on its back side by means of a bottom substrate28and the frame structure30b.

As a further embodiment,FIG. 6again shows a cross-sectional representation of a micromechanical device9, which is configured in analogy to the embodiment ofFIG. 5, wherein the packaged micromechanical device9is on its top side and/or front side sealed by means of an optical cover glass26so as to enable hermetic sealing and protection for the device. The optical cover glass26is aligned in parallel with the micromechanical device and permanently connected to the support structure32of the microactuator structures24. In the area of the optically effective range of the packaged microdevice, the support structure has a free aperture for unobstructed optical coupling and decoupling.

In a further embodiment of the present invention, a device analogous toFIG. 5is represented inFIG. 7, but the packaged micromechanical device9is, however, on its top side sealed by means of an optical cover glass36, wherein the optical window is oriented in a tilted manner with respect to the packaged micromechanical device9and the support structure32. Here, the tilting of the optical cover glass36may be effected via a correspondingly formed window mount38, wherein the latter may be permanently connected to the support structure32.

InFIG. 8, a further embodiment of the present invention is represented. A micromechanical device9is shown in the form of a single device40packaged at chip level having tilted electrode structures12deflected downwards. The micromechanical device chip40is positioned in a cavity41of a package42, which may be comprised of a ceramic or metal, such as a metal-CAN package, plastic or glass, for example, and permanently connected thereto. The micromechanical device chip40may be connected to the external package42by e.g. adhering44, bonding or soldering or any other connecting means. The support structure32of the microactuator structures24may be connected to the external package by means of adhering, bonding, soldering or any other connecting means, for example. The support structure, including the micromanipulator structures or microactuator structures, is aligned relative to the micromechanical device40. The deflection or tilting of the two-dimensional structures is then effected in joining the support substrate32and the external package42. If the device is an optical one, such as in this embodiment, the support structure may exhibit a free optical aperture34for unobstructed optical coupling and decoupling in the area of the optically effective ranges of the microdevice. For hermetically sealing the package, the entire package42may be sealed by means of a cover glass26aligned in parallel with the support structure32and permanently connected thereto.

Alternatively, as shown in the embodiment ofFIG. 9, the micromechanical device9packaged at chip level as a single device40may, with its tilted structures12deflected downwards by means of micromanipulator structures24, comprise an optical window36tilted with respect to the micromechanical device9. The tilting of the optical window36may be achieved via a respectively formed window mount38, wherein the latter may be permanently connected to the support structure32. It may also be conceivable that the support substrate32itself serve as the window mount and for this purpose be correspondingly three-dimensionally structured, e.g. wedge-shaped, so that the optical window36is tilted with respect to the microdevice40. The fabrication of such a three-dimensional support substrate may be effected by means of mechanical micro precision machining, micro forming, micro injection molding or by means of the so-called LIGA (lithographic galvanic forming) technology.

FIG. 10shows a further embodiment of the present invention in a cross-sectional representation through a micromechanical device9comprising the above-described structures. However, in this embodiment, the deflected tilted two-dimensional structures, which may be comb electrodes of a scanner mirror, are deflected in the direction of the cap structure or the optical cover glass26. Concerning this, the microactuator structures24necessary for deflecting the two-dimensional structures may be located on the back and/or under side or on the bottom substrate of the micromechanical device9and be permanently connected thereto. The bottom substrate28may be aligned relative to the micromechanical device substrate14and permanently connected thereto such as by adhering, wafer bonding, soldering or by means of the SLID procedure. The deflection of the two-dimensional structures may be effected by means of the microactuator structures24in the joining or packaging of the bottom substrate28and the device substrate14. Again, there may optionally be an optical cover glass26on the top side of the micromechanical device9, which may serve as a window. The frame or frame structures30a,30bmay serve as spacers to the optical window and form a cavity41above the optically effective area of the microdevice.

FIG. 11shows a further embodiment of the present invention with the micromechanical device exhibiting two-dimensional structures deflected in the direction of the device top side, i.e. in the direction of the cover glass26. The microactuator structures necessitated for this purpose attack on the top side of the tiltable electrodes12. The microactuator structures24are permanently connected to an optional support substrate26or directly to the optical cover glass. The tilting or deflection of the two-dimensional structures in the direction of the top side of the micromechanical device9is in this example achieved by the force action and the application of a torque on the short side of the attacking lever arm which is formed between the torsion springs16and the location of the force action on the electrodes12. The cover glass26and/or the support structure may again be permanently connected to the microdevice substrate14via a spacer30a. In the embodiment, only the cover glass26is shown without the optional support structure32.

FIG. 12shows an embodiment with tilted two-dimensional structures12alternately deflected upwards and downwards. Again, the tiltable, stationary comb electrodes12of the one-dimensional scanner mirror already mentioned above may be concerned. The microactuator structures24used for deflecting the two-dimensional structure are located both on the top and the under side of the micromechanical device. The microactuator structures24are connected either to the bottom substrate28and/or the front-side support structure or directly to the window glass26. By means of the microactuator structures, the two-dimensional structures are deflected in the joining or packaging of the micromechanical device substrate14with the bottom substrate28and cover and/or window substrates26and the respective frame structures30aand30b.

In the embodiment inFIG. 13, with tilted two-dimensional structures12deflected alternately upwards and downwards, the microactuator structures24attack on the top side and/or front side of the structures12, i.e. from the top side of the device9. The micromanipulator structures24are permanently connected to an optional support substrate or directly to the optical cover glass26. The cover glass and/or the support structure is again permanently connected to the microdevice via a spacer of the frame structures30aand/or30b. In the embodiment shown, again only the cover glass is shown without the optional support structure.

The position of the contact pads18of the deflectable two-dimensional structures12for the force initiation of the micromanipulator structures is arranged such that the microactors alternately deflect or tilt the two-dimensional structures downwards and, alternately, upwards. A substantial advantage of the embodiment shown consists in the high robustness towards lateral alignment tolerances of microactuator structures and two-dimensional structures to be deflected, as lateral alignment tolerances also effect a tilting of the structures, with the result that the symmetry of the device is not disturbed.

FIG. 14shows an embodiment analogous toFIG. 13having two-dimensional structures alternately deflected in the directions of the top and under side of the micromechanical device. The microactuator structures24attack on the under side of the device, which is realized in the frame14. The microactuator structures may be permanently connected to the bottom substrate, which is, in turn, permanently connected to the microdevice. In analogy toFIG. 13, the embodiment shown has the advantage of high robustness towards lateral alignment tolerances of microactuator structures and two-dimensional structures to be deflected, as deflected two-dimensional structures may also be created with lateral alignment tolerances, with the result that the symmetry of the device is not disturbed.

FIG. 15shows a schematic embodiment of a packaged microdevice9having two-dimensional structures pre-deflected via microactuator structures24, wherein, for the reduction of assembly tolerances, a self-alignment of deflecting microactuator structures24and two-dimensional structures12to be tilted may be achieved by means of self-aligning assembly structures50. The auto-alignment structures50are present both in the micromechanical device40and in the support substrate26,30awith the microactuator structures24, which is to be joined thereto.

FIG. 16shows a further embodiment of a micromechanical device9, wherein two-dimensional structures may be deflected by means of micromanipulator structures during the device packaging process. In contrast to all the above embodiments having the two-dimensional structures to be deflected rotatorily supported by means of torsion springs16, the two-dimensional structures to be deflected inFIG. 16are supported via a parallel joint52. By means of supporting the deflectable two-dimensional structure, such as the electrode combs12, as a parallel joint, a parallel shift of the contact pad18guided in parallel to the force initiation is effected in the structure deflection by means of the microactuator structures24. In the embodiment shown inFIG. 16, the structure to be deflected, such as the stationary drive electrode12, is rigidly coupled to the rotatorily supported linkage of the parallel joint52so that the relevant two-dimensional structure12is tilted. The absolute tilt angle of the two-dimensional structure substantially only depends on the height of the parallel shift of the contact pad18as caused by the lowering of the microactuator structure24during packaging. In contrast to that, the lateral position of the force initiation within the contact pad18is of no importance, so that the resulting tilt angle of the two-dimensional structure is independent of the otherwise critical lateral alignment tolerances. Thereby, identical tilt angles with large reproducibility as well as better symmetry of the device may be realized for several two-dimensional structures to be simultaneously deflected.

In the embodiment shown inFIG. 16, the two-dimensional structures12to be deflected are both tilted downwards, wherein the microactuator structures24, which are permanently connected to the window substrate26and/or an optional support substrate, attack the contact pad18from the top side and shift same in the direction of the bottom substrate28in a defined and parallel manner so that the two-dimensional structure, such as the stationary drive electrode structure12, is symmetrically tilted.

FIG. 17shows an embodiment in analogy toFIG. 16, wherein the two-dimensional structures12to be deflected are tilted in the direction of the cap structure26. For this purpose, the deflecting micromanipulator structures24attack from the device back side and/or the bottom substrate28so as to, as a result of the support via a parallel joint52a-c, effect a parallel shift of the contact pads18as well as a symmetrical tilting of the two-dimensional structures in the direction of the cap structure26. The microactuator structures24may be permanently connected to the bottom substrate28.

FIG. 18shows a further embodiment similar toFIG. 17. In contrast toFIG. 16, the two-dimensional structure12to be deflected is permanently, i.e. rigidly, coupled to the contact pad18serving for the transmission of force. Hereby, in lowering the micromanipulator structures, i.e. in packaging, the two-dimensional structure12to be deflected is shifted upwards in parallel in a manner simultaneous to the contact pad18so that the two-dimensional structure12, in its deflected final state, is aligned in parallel, at a distance defined via the geometry and/or the height of the micromanipulator, and positioned above the device substrate14.

In analogy toFIG. 16,FIG. 19shows a further embodiment of a packaged micromechanical device, wherein the relevant two-dimensional structures12are deflected in parallel to the device frame substrate14. In contrast toFIG. 18, the deflection of the two-dimensional structures12is effected downwards and in the direction of the bottom substrate28, by means of the microactuator structures24attacking on the top side of the contact pads18, in analogy toFIG. 16.

FIG. 20shows the cross-sectional representation for dicing packaged microdevices9that do not comprise any optical window cover substrate. The two-dimensional deflected structures12are deflected by means of microactuator structures24, attacking via the back side, from the bottom substrate28.FIG. 20shows the state after the dicing of the devices in the wafer matrix by means of sawing. A spacer frame structure30a, which is adhered to a support foil54, the so-called blue tape, or any other auxiliary support structure during the dicing such as a sawing of the wafer, is located on the device front side and is permanently connected thereto.

The embodiment ofFIG. 21again shows the dicing of packaged microdevices9without an optical window cover substrate, comprising, however, two-dimensional structures12deflected via microactuator structures24attacking from the front side, i.e. from the support substrate32. The state after the dicing of the devices in the wafer matrix by means of sawing is shown. Located on the device front side and/or top side, there is a spacer frame structure30apermanently connected thereto, as well as the support substrate32of the microactuator structures24, which is permanently connected thereto. In dicing, e.g. wafer sawing, the wafer matrix may, with the front-side support substrate32, be adhered to a support foil54, such as a so-called “blue tape” or any other auxiliary support substrate.

As an embodiment of a micromechanical device9,FIG. 22shows a scanner mirror56formed in the device substrate14. The scanner device56is rotatorily supported in an external stationary frame60via additional torsion springs58arranged coaxially with respect to the actual torsion springs20. The entire micromechanical device56is then tilted together with the device substrate14during packaging.

Again, the scanner mirror56comprises a mirror plate15and torsion springs16, amongst others, for the deflection of the stationary electrodes12, which include a contact pad18.

FIG. 23shows the embodiment of a tilted microdevice substrate56equivalent toFIG. 22, which is permanently deflected via respective microactuator structures24, in the device packaging. During the device sealing, i.e. during the packaging, the entire micromechanical device56, such as a two-dimensional micro mirror is tilted via the microactuator structures24together with the substrate14, which, as described above, for this purpose is rotatorily supported in an external stationary frame60via torsion springs58. The meandering springs58either exhibit the same torsion axis20as the mirror plate15of the two-dimensional scanner56or a torsion axis coaxial or rotated thereto. The external stationary frame60may be permanently connected to the bottom substrate28and a spacer and window substrate26aligned in parallel thereto. The microdevice substrate14with the two-dimensional scanner mirror56may therefore be arranged in a manner tilted relative to the cap structure26.

This means that the method of generating 3D structures may be performed on a wafer such that same contains 2D structures manufactured in the wafer matrix, released and connected to the wafer via bearings which are designed for static anchorage outside the wafer plane. The 2D structures may be moved out of the wafer plane and be erected to form 3D structures by means of one or more micromanipulators. The deflection or tilting of the 2D structures for the realization of 3D structures may be effected during the packaging process of the micromechanical device. After their deflection out of the wafer plane, the 2D structures may be anchored in their position, wherein the micromanipulators are permanent components of the device.

In embodiments of the invention, the micromanipulator may also be a permanent component of the two-dimensional structure. I.e., the two-dimensional structure may itself comprise the micromanipulator. The micromanipulator integrated into the two-dimensional structure may then be deflected and arranged between the package and the two-dimensional structure such that the two-dimensional structure is deflected out of a plane of the substrate.

The micromechanical device with the two-dimensional structure may be a scanner mirror with drive and/or comb electrodes, for example, which may be deflected quasi-statically, resonantly or statically. In the following, the two-dimensional structure may also be referred to as a micromechanical functional structure. For the quasi-static or resonant operation of the micromechanical device according to a further embodiment of the present invention the micromechanical device may further comprise means for providing a varying voltage. These means may comprise conductive-trace lead-ins, contact pads and circuits suitable for applying the respective voltages to the comb electrodes. These means may also comprise a control apparatus, whereby periodic voltages having a frequency necessary for the proper operation of the micromechanical functional structure may be applied to the comb electrodes in the resonant case. The control apparatus may further comprise means for detecting the zero crossings of the two-dimensional micromechanical structure oscillating on a main axis. Furthermore, the micromechanical device may serve as a sensor and use the above means for detecting a movement of the micromechanical functional structure.

In a further embodiment of the present invention, rather than torsion springs, flexion springs may be used, for example, for the suspension of fixed combs of a scanner mirror.

Additional comb-electrode structures of a scanner mirror in another embodiment of the invention may be disposed on the micromechanical device such as the scanner plate. In contrast to the above embodiments, the micromechanical functional structure may be suspended rotatorily and two-dimensionally such that the micromechanical functional structure, such as a mirror plate, may be deflected in two directions and shifted translationarily. Similarly, such a structure may have the torsion axes mutually rotated by 90 degrees. The rotation axes may be mutually rotated by an arbitrary angle. As a special case, a rotatorily constructed two-dimensional structure may comprise collinear axes, for example, wherein, by means of the collinear axes, a larger deflection angle may specifically be achieved. The two-dimensional rotatorily deflectable structure may be configured such that one of the deflection movements is achieved by means of a different principle of effect, such as a magnetic, piezoelectric, thermal or acoustic principle of effect. The two ways of deflection in two dimensions may both be effected in a quasi-static or resonant manner, or one deflection may be effected in a quasi-static manner and the other in a resonant manner.

Furthermore, a micromechanical device comprising a two-dimensional rotatorily deflectable structure may be configured such that one of the deflections may be realized by means of an electrostatic in-plane drive (EP 11 23 526).

The micromechanical functional structure may be rotatorily deflectable in one or two dimensions, for example, wherein at least one deflection direction is operated by means of the tilted comb arrangement described in the embodiments, and may comprise additional diffractive elements on or in the micromechanical functional structure and/or additional highly reflective mirror platings. They may be diffractive optical elements (DOE), gratings, metallic mirror platings, dielectric mirror platings, coated metallic mirror platings and the like.

In embodiments, the comb electrodes (combs) of a scanner mirror may, by one or more mandrels, be deflected out of or under the chip plane given by the rest position of the mirror plate and the frame structure, in any direction, depending on the design and structuring of the micromechanical device. The deflection of the combs may specifically be effected such that all combs are deflected upwards, downwards, in symmetry with an axis through the device center or in point symmetry with the device center or completely asymmetrically.

The micromechanical device may comprise a control apparatus or may be driven by a control apparatus so that the creatable movement of the micromechanical functional structure follows a ramp with fast reverse motion. The control apparatus may be configured such that a linear translatory movement is caused by the electrostatic comb drive, which is functionally described by z(t)=C1×t, wherein the exact linear functional connection between the deflection z and the time t is given by a constant C1. In analogy, the electrostatic comb drive may be controlled such that a linear rotatory movement with an angle deflection φ(t)=C2×t is yielded. The deflection angle φ is therefore directly proportional to the deflection time t of the rotatory movement.

The two-dimensional structure, i.e. the scanner mirror, for example, may also exhibit a form of movement adapted to the application so that a linear movement of a laser spot deflected by a scanner mirror is effected on a view screen. The control for applying a respective voltage to the tilted electrode combs of the present invention may also be effected in that the back-and-forth course of a laser spot deflected by the scanner mirror is effected at different speeds or at the same speed, wherein the reversal points of the back-and-forth course are blanked out on the screen.

In a further embodiment, the tilted comb electrodes and the ways for translatory movement may also be used for an exact optical path-length modulation in optical appliances by means of a respective control apparatus. The optical path-length modulation may be effected both translatorily and rotatorily. The translatory movement by means of the tilted comb structure may also be used for extending the optical path length of an appliance. The two-dimensional structure may, for example, also be translatorily moved in one or two dimensions, wherein the movement in at least one direction is effected by means of the tilted comb arrangement, wherein additional diffractive elements are arranged in the micromechanical device. Examples are DOEs, gratings, metallic mirror platings, dielectric mirror platings, coated metallic mirror platings and the like.

The micromechanical device of the present invention may be used for the optical path-length modulation for confocal microscopes, for Fourier transform spectrometers and/or for adjusting the resonator length in lasers, as well as for selecting and/or varying the laser wavelength. An arrangement of a linear or two-dimensional array constructed of one- or two-dimensional, translatory or rotatory elements according to the present invention is also conceivable.

The micromechanical functional structure may be a mirror plate having both the front and the back side mirror-plated.

Micromechanical devices realizing a combination of the suggested approach with the tilted comb structures with other principles of effect, which are operated quasi-statically, resonantly, translatorily or rotatorily, are also conceivable.

In a further embodiment of the invention, for feeding further electrical potentials, the micromechanical devices may comprise multi-springs or metallic conductive traces via springs or highly doped areas in a weakly doped substrate. In the micromechanical device, fingers of an electrode comb may be attached to a torsion spring or a device area that is more rigid than a torsion spring, on which the micromechanical device may be rotated. The fixed comb structures with their fingers and the movable comb structures with their fingers may be formed in different substrate or frame layers. In addition, rather than torsion springs, flexion springs may be used, which comprise contact pads, which may be subjected to a force action for the deflection of the fixed combs, and/or which may be shifted in parallel via a four-hinged joint.

According to embodiments, the micromechanical device may be employed for image projection or for positioning a light or laser beam. The micromechanical device may, for example, be employed for deflecting or positioning a light or laser beam, which is operated in a continuous or pulsed manner.

The Micromechanical device may be formed in varying substrates such as silicon, gallium arsenide, indium phosphide, gallium nitride, silicon carbide or any other substrates. The actor layer may be poly- or mono-crystalline.