Micromechanical structure

Abstract

Micromechanical structure (1), in particular a gyroscope, comprising a substrate (2) having a principal extension plane (100), a first detection mass element (11) and a second detection mass element (21), wherein the first detection mass element (11) is provided to be excitable by a first drive element (10) to a first vibration (101) parallel to the principal extension plane (100), wherein the second detection mass element (21) is provided to be excitable by a second drive element (20) to a second vibration (201) antiparallel to the first vibration (101), wherein a first Coriolis deflection of the first detection mass element (11) along a third direction (Z) perpendicular to the principal extension plane (100) is detectable by a first detection means,wherein a second Coriolis deflection of the second detection mass element (21) along the third direction (2) is detectable by a second detection means and wherein the first and the second detection mass elements (11, 21) are coupled to each other by means of a first coupling element (3), characterized in that the first detection mass element (11) is designed as a first rocker structure (11') and the second detection element (21) as a second rocker structure (21'), wherein the first and second rocker structures (11' and 21') are attached to the first and second drive elements (10 and 20) by means of a first and second torsion spring (13 and 23, respectively), respectively, wherein the first and second torsion axis (13' and 23') of the first and second torsion spring (13, 23) are parallel to the first and second directions (X, 2, 3, 4, 5, 6, 7, 8, 9, 10 ...Y) is provided and the first or second rocker structure (11' or 21') has an asymmetric mass distribution with respect to the first or second torsion axis (13' or 23'), wherein the first and / or the second torsion spring (13, 23) are designed as a conductor spring, wherein the first and / or the second torsion spring (13, 23) are designed as a double conductor spring.

Description

State of the art

[0001] The invention relates to a gyroscope according to the preamble of claim 1.

[0002] Such micromechanical structures are generally known. For example, German patent DE 10 2006 047 135 A1 discloses a gyroscope with two identical structures, each structure having two drive mass elements connected to a substrate via four drive mass springs and each connected to a sensing mass element via eight sensing mass springs. The two sensing mass elements are coupled to each other via a coupling spring. The two drive mass elements are driven to vibrate along a first axis parallel to the surface of the substrate, while the sensing mass elements can be deflected along a second axis perpendicular to the surface under the influence of Coriolis forces.Furthermore, the gyroscope has detection devices below the detection mass elements, through which the deflections of the detection mass elements can be detected, so that the gyroscope is provided for detecting a gyroscope rate about a rotation axis perpendicular to the first and second directions.

[0003] The mass structures are typically designed with perforations to allow for the isolation of the moving structures (first and second sensing elements, first and second drive elements), particularly during etching processes such as gas-phase etching. The mass of the mass structures, therefore, depends on the width of the mass webs and the size of the perforations for a given layer thickness. Manufacturing-related variations in the trench widths of the spring and mass webs, referred to below as edge loss variations, unfortunately lead to frequency variations in the respective spring-mass system.Furthermore, a disadvantage of the prior art gyroscope is that the single-sided positioning of the detection device, in the form of electrodes below the detection mass elements, creates the risk that the detection mass elements will be pulled downwards towards the electrodes when a positive feedback voltage and a quadrature compensation voltage are applied. At very high voltage levels, this can even lead to electromechanical instability, the so-called "snapping," in which the detection mass elements are pulled completely onto the electrodes. In practice, the positive feedback voltage compensates for a frequency offset between the drive mode and the detection mode of the gyroscope, allowing the gyroscope to operate in full resonance. The set frequency offset serves to compensate for manufacturing tolerances; hereafter, the frequency offset is also referred to as frequency splitting.Furthermore, the quadrature compensation voltage suppresses mechanical and electrical crosstalk from the drive movement into the detection path. The vibration sensitivity of the gyroscope is proportional to the quadrature and frequency splitting, so that achieving the lowest possible vibration sensitivity requires the lowest possible quadrature and frequency splitting. However, in the gyroscope, the suspension springs used to attach the detection mass elements are primarily subjected to bending stress during deflection. The bending stiffness of the suspension springs increases proportionally to the cube of the functional layer thickness, while the mass increases only linearly with the functional layer thickness. Consequently, the detection frequency exhibits a strong dependence on the functional layer thickness, while the drive frequency does not vary, or only minimally, with the functional layer thickness.For fully resonant operation of the gyroscope, a comparatively large frequency split must therefore be set, which is disadvantageous in order to compensate for manufacturing tolerances in the production of the gyroscope. However, this also increases the vibration sensitivity described above.

[0004] Further micromechanical structures are known from publications DE 196 39 946 B4, DE 10 2008 012 825 A1, US 2004 / 0 206 176 A1 and DE 10 2007 054 505 A1. Disclosure of the invention

[0005] The micromechanical structures described here offer an advantage over the prior art in that interferences affecting the drive and / or detection frequency are significantly reduced, both due to manufacturing-related variations in the functional layer thickness perpendicular to the main extension plane and due to manufacturing-related variations in the width of trench structures parallel to the main extension plane. This is achieved by selecting a specific ratio between the width of the mass webs and the web width of the bending spring elements. Both the width of the mass webs and the web width of the bending spring elements each encompass the effective width, i.e., the width of the mass webs after processing the micromechanical structure (in particular, after undercutting with the seismic mass).The average width of the mass webs is between 20 and 50 percent, preferably between 25 and 40 percent, particularly preferably between 30 and 36 percent, and most preferably essentially at 33 percent of the web width of the bending spring elements. This significantly increases the absolute accuracy in setting the drive and / or detection frequency compared to the prior art. The micromechanical structure preferably comprises a micromechanical resonator or a micromechanical rotation rate sensor.

[0006] The present invention relates to a micromechanical structure, in particular a gyroscope, comprising a substrate having a principal extension plane, a first sensing mass element and a second sensing mass element, wherein the first sensing mass element is provided to be excitable by a first drive element to a first oscillation along a first direction X parallel to the principal extension plane, wherein the second sensing mass element is provided to be excitable by a second drive element to a second oscillation antiparallel to the first oscillation, wherein a first Coriolis deflection of the first sensing mass element along a third direction perpendicular to the principal extension plane is detectable by a first sensing means.wherein a second Coriolis deflection of the second detection mass element along the third direction is detectable by a second detection means, and wherein the first and second detection mass elements are coupled to each other by means of a first coupling element, and wherein the first detection mass element is designed as a first rocker structure and the second detection element as a second rocker structure. This micromechanical structure has the advantage over the prior art that the detection frequency of the micromechanical structure exhibits only a slight dependence on the thicknesses of the first or second detection mass elements perpendicular to the main extension plane (also referred to as functional layer thickness).This means that the detection frequency varies significantly less with fluctuations in the thicknesses of the first and second detection mass elements. Advantageously, this allows for a lower frequency split between the drive and detection modes, thereby massively improving the vibration resistance of the micromechanical structure compared to the prior art. The design of the first and second detection mass elements as first and second rocker structures means that their deflection results only in torsion of the suspension springs of the first and second detection mass elements. The detection frequency is therefore not, or only insignificantly, dependent on the thickness of the corresponding functional layer perpendicular to the principal extension plane (along the third direction Z).Since the detection frequency depends on the quotient of the spring stiffness of the corresponding torsional spring and the moment of inertia of the first or second rocker structure about the first or second torsional axis, and since both the spring stiffness at a comparatively large aspect ratio and the moment of inertia are approximately proportional to the functional layer thickness. A further advantage of the first and second rocker structures is their very high natural frequency for a parasitic z-translation mode (direction of motion perpendicular to the principal extension plane) compared to the torsional mode (useful mode). This means that when electrical voltages are applied to electrodes arranged perpendicular to the principal extension plane between the first or second detection mass element and the substrate,Essentially, no static deflection of the first or second detection mass element occurs, and the dynamic excitability of the z-translation mode is significantly lower. The micromechanical structure according to the invention is therefore considerably less sensitive to attraction of the detection mass elements towards the substrate and, in particular, to the aforementioned "snapping" effect. Furthermore, the comparatively low frequency splitting helps to keep the voltage levels required for full resonant positive feedback low and to prevent possible parasitic excitation of the z-translation mode. At the same time, the micromechanical structure according to the invention enables coupling of the first and second detection mass elements via the first coupling element, thus advantageously ensuring coupling of both the drive modes and the detection modes.

[0007] Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings.

[0008] According to the invention, the first and second rocker structure are attached to the first and second drive element, respectively, by means of a first and second torsion spring, respectively, wherein the first and second torsion axis of the first and second torsion spring is parallel to the first and second directions, respectively, and the first and second rocker structure has an asymmetric mass distribution with respect to the first and second torsion axis. Particularly advantageously, when a force acts on the first or second rocker structure perpendicular to the main plane of extension, especially due to a Coriolis force, the asymmetric mass distribution of the first and second rocker structure with respect to the first and second torsion axis generates a torque on the first and second sensing mass element about the first and second torsion axis, respectively. This torque generates a first and second deflection of the first and second sensing mass element.The second detection mass element is detectable by first and second detection devices in the form of electrodes. The detection device comprises, in particular, electrodes arranged perpendicular to the main extension plane between the first and second detection mass element and the substrate, and which, for differential evaluation of the first and second deflection, are preferably arranged parallel to the main extension plane on both sides of the first and second torsion axis.

[0009] According to the invention, the first and / or the second torsion spring is designed as a conductor spring, wherein the first and / or the second torsion spring is designed as a double conductor spring. In a preferred embodiment, the first and / or second torsion spring is designed as a multiple conductor spring. The conductor spring comprises, in particular, two parallel silicon beams which are connected to each other at regular intervals by transverse rungs. This particularly advantageously increases the ratio of the bending stiffness along the first direction X parallel to the main extension plane to the torsional stiffness.

[0010] According to a further preferred embodiment, the first and second detection mass elements are attached to the substrate by means of second coupling elements, wherein the first and / or the second coupling elements in particular comprise bending springs, which are preferably meander-shaped. The first and second detection elements are particularly advantageously stabilized by the connections to the substrate via the second coupling elements.

[0011] According to a further preferred embodiment, the first and second drive elements are attached to the substrate by means of third coupling elements, wherein the third coupling elements in particular comprise further bending springs, which are preferably meander-shaped. It is particularly advantageous that the first and second drive elements are attached to the substrate by the third coupling elements, wherein the drive mode exhibits no or only an insignificant dependence on the functional layer thickness, since the bending stiffness of the further bending springs along the first direction X and the total drive mass of the first or second drive element along the first direction X are each proportional to the functional layer thickness.The drive frequency is proportional to the quotient of bending stiffness and drive mass, from which the functional layer thickness consequently cancels out, so that the drive frequency along the first direction X advantageously depends not on the functional layer thickness or only insignificantly. The frequency splitting is also particularly advantageous because it is only relatively weakly dependent on the functional layer thickness, so that a comparatively small frequency split can be set.

[0012] According to a further preferred embodiment, the first and / or second coupling elements are more compliant with respect to deformation parallel to the first vibration and / or parallel to the third direction than with respect to deformation along a direction perpendicular to the first vibration and the third direction. This particularly advantageously suppresses vibration of the first and second detection elements along the second direction Y, while favoring antiparallel first and second vibrations.

[0013] According to a further preferred embodiment, the first drive element is designed to essentially completely surround the first detection mass element parallel to the main extension plane, and / or the second drive element is designed to essentially completely surround the second detection element parallel to the main extension plane, with the first and / or the second detection element each having only one opening for the first and / or the second coupling elements. This particularly advantageously enables a comparatively symmetrical design of the first drive element together with the first detection mass element and a comparatively symmetrical design of the second drive element together with the second detection mass element, thus reducing structural interferences on the drive and detection modes, for example, due to parasitic capacitances, on the part of the first and second drive elements.

[0014] According to a further preferred embodiment, the outer circumference of the first detection mass element and the outer circumference of the second detection mass element are symmetrical with respect to the first torsion axis. It is particularly advantageous to increase the symmetry of the first drive element together with the first detection mass element and of the second drive element together with the second detection mass element, so that structural disturbances affecting the drive and detection modes, for example, due to parasitic capacitances, are also reduced on the part of the first and second detection mass elements. In particular, an additional frame is attached to the shorter side of the first and second rocker structure, which is required to generate the mass asymmetry of the first and second rocker structure, respectively, so that the outer circumference of the first and second rocker structure is increased.The second rocker structure is essentially symmetrical with respect to the first and second torsion axes. Alternatively, an additional web is provided on the shorter side for the symmetrical attachment of the first coupling element.

[0015] According to a further preferred embodiment, the first and / or the second detection mass element comprises a second seismic mass with second mass webs, wherein the bending springs comprise second bending spring elements, and wherein the ratio between a second web width of the second mass webs and a further second web width of the second bending spring elements is equal to the ratio between the first web width and the further first web width. By appropriately selecting the second web width and the further second web width, the variations in the detection frequency due to edge loss variations can be advantageously minimized compared to the prior art, thus significantly increasing the absolute accuracy in setting the detection frequency.

[0016] Exemplary embodiments of the present invention are shown in the drawings and explained in more detail in the following description. Brief description of the drawings

[0017] They show Fig. 1 a micromechanical structure according to the state of the art and Fig. 2 a micromechanical structure according to a first embodiment, Fig. 3a and Fig. 3b a schematic representation of the frequency dispersion as a function of the edge loss in a micromechanical structure according to the prior art and in a micromechanical structure according to the first embodiment, Fig. 4a and Fig. 4b a schematic top view and a schematic side view of a micromechanical structure according to a second embodiment of the present invention, Fig. 5a and Fig. 5b a schematic top view and a schematic side view of a micromechanical structure according to a third embodiment of the present invention, Fig. 6 a schematic top view of a micromechanical structure according to a fourth embodiment of the present invention, Fig. 7a and Fig. 7b a schematic top view and a schematic side view of a micromechanical structure according to a fifth embodiment of the present invention, Fig. 8 a schematic top view of a micromechanical structure according to a sixth embodiment of the present invention, Fig. 9 a schematic top view of a micromechanical structure according to a seventh embodiment of the present invention, Fig. 10 a schematic top view of a micromechanical structure according to an eighth embodiment of the present invention, Fig. 11 a schematic top view of a micromechanical structure according to a ninth embodiment of the present invention, Fig. 12 a schematic view of the change in detection frequency as a function of the functional layer thickness of a micromechanical structure according to the second embodiment of the present invention and Fig. 13 a schematic view of the change in detection frequency as a function of edge loss of a micromechanical structure according to the second embodiment of the present invention. Embodiments of the invention

[0018] In the various figures, identical parts are always marked with the same reference symbols and are therefore usually only named or mentioned once.

[0019] In Fig. Figure 1 is a gyroscope in the form of a micromechanical structure 1 according to the prior art, wherein the gyroscope has a substrate 2 with a principal extension plane 100. Furthermore, the gyroscope comprises a drive element 10, which is attached to the substrate 2 by means of third coupling elements 4 in the form of further bending springs and which is excited to a first oscillation 101 along a first direction X parallel to the principal extension plane 100 by means of first comb drives 14. A first detection mass element 11 is movably connected to the drive element 10 by means of further coupling means 300. The gyroscope also comprises an identical second drive element 20 with a corresponding second detection element 21 and second comb drives 24.The first and second detection mass elements 11, 21 are coupled to each other by means of a first coupling element 3 and each connected to the substrate 2 by means of a second coupling element 5. The first oscillation 101 and the second oscillation 201 are antiphase to each other along the first direction X. If a rotation rate about an axis of rotation along a second direction Y, which is parallel to the principal plane 100 and perpendicular to the first direction X, is applied, a first and second Coriolis force parallel to a third direction Z, perpendicular to the principal plane 100, acts on the first and second detection elements 11, 21, respectively, with the first and second Coriolis forces being antiparallel to each other.This generates a first and second deflection of the first and second detection mass elements 11, 21 parallel to the third direction Z, which are detected by means of first and second detection devices in the form of electrodes on the substrate 2. These electrodes are arranged along the third direction Z between the substrate 2 and the first or second detection mass element 11, 21, respectively. The first and second detection mass elements 11, 21 are designed as perforated masses comprising a lattice structure of intersecting mass struts. The perforations serve, for example, as etching channels for the etching medium when under-etching the first and second mass elements 11, 21. Similarly, the first and second drive elements 10, 20 also comprise a lattice structure with further mass struts.

[0020] In Fig. 2 is a micromechanical structure 1 according to a first embodiment, wherein the micromechanical structure 1 comprises a substrate 2 and a first seismic mass 202, the substrate 2 comprising a principal extension plane 100. The first seismic mass 202 has a lattice structure of intersecting first mass webs 203, the mass webs 203 each having a first mass web width 205 parallel to the principal extension plane 100. The first seismic mass 202 is elastically attached to the substrate 2 by means of first bending spring elements 204, the bending spring elements 204 each having a further first web width 206 parallel to the principal extension plane 100. The first web width 205 is approximately 33 percent of the further first web width 206.

[0021] In Fig. 3a and Fig. Figure 3b is a schematic representation of the frequency dispersion as a function of edge loss for a micromechanical structure 1 according to the prior art and for a micromechanical structure according to the one described in Fig. The first embodiment is shown in Figure 2, with the edge loss plotted on the abscissas 210 and the relative frequency change in percent plotted on the ordinates 211. In the embodiment shown in Fig. In the illustrated curve 212 of the relative frequency change as a function of edge loss in a micromechanical structure 1 according to the prior art, an essentially linear relationship between the frequency change and the edge loss can be observed. In contrast, in the Fig. 2b illustrated course 213 of the relative frequency change as a function of edge loss in a micromechanical structure 1 according to the in Fig. In the first embodiment shown in 2, the frequency change is significantly less dependent on the edge loss.

[0022] In Fig. 4a and Fig. Figures 4b show a schematic top view and a schematic side view of a micromechanical structure 1 according to a second embodiment of the present invention, wherein the Fig. 2a first embodiment shown is essentially as shown in Fig. 1 according to the prior art, wherein the first detection mass element 11 is designed as a first rocker structure 11' and the second detection mass element 21 as a second rocker structure 21'. The first rocker structure 11' is attached to the first drive element 10 in the form of a ladder spring by means of a first torsion spring 13, wherein the first rocker structure 11' has an asymmetric mass distribution with respect to a first torsion axis 13' defined by the torsion spring 13 along the second direction Y, such that the first deflection by a first Coriolis force along the third direction Z causes a rotation of the first rocker structure 11' about the first torsion axis 13'. The ladder spring has, in particular, a high bending stiffness along the first and third directions X, Z in order to prevent undesired deflections of the first and second rocker structures 11', 21' relative to the first and second drive elements 10, 20 during the first and second oscillations, respectively.to prevent disturbances and accelerations along the third direction Z. The ratio between bending stiffness and torsional stiffness is increased by using comparatively short conductor springs. Between the first rocker structure 11' and the substrate 2, a first electrode 16 and a further first electrode 17 are arranged such that the first torsional axis 13' runs parallel to the main extension plane 100 between the first and the further first electrode 16, 17. The first deflection thus generates an opposite change in capacitance at the first and further first electrode 16, 17, so that the first deflection can be evaluated differentially. Similarly, a second and a further second electrode 26, 27 are arranged below the second rocker structure 21'. Fig. Figure 2b shows a section through the first and second seesaw structure 11', 21' along the in Fig. 2a shows line 100', illustrating a first deflection of the first seesaw structure 11' and a second deflection of the second seesaw structure 21' from their respective rest positions, which are parallel to the principal extension plane 100, due to a Coriolis force. The first and second deflections are in the same direction, since the geometry of the first and second seesaw structures 11', 21' with respect to the Fig. The mirror plane 100" shown in Figure 2a is designed to be mirror-symmetric to each other. To achieve coupling of the first and second rocker structures 11', 21' in both the drive and detection directions, the first and second rocker structures 11', 21' are connected to each other via a first coupling element 3, wherein the first coupling element 3 preferably has a well-defined stiffness along the first and third directions X, Z and is designed to be as stiff as possible along the second direction Y. In the Fig. In the first and second deflections shown in Figure 4b, the first coupling element 3 is loaded along the third direction Z. The first drive element 10 is further configured such that it essentially completely surrounds the first detection mass element 11 parallel to the main extension plane 100, with the first detection element 11 having only one opening 11" each for the first and second coupling elements 3, 5. The second drive element 20 is configured analogously. Furthermore, the first and second detection mass elements 11, 21 each comprise a second seismic mass (analogous to the one shown in Figure 4b). Fig. 2 in the first embodiment shown) with second mass webs, wherein the bending springs comprise second bending spring elements and wherein the ratio between a second web width of the second mass webs and a further second web width of the second bending spring elements is equal to the ratio between the first web width and the further first web width. Likewise, the first and the second drive elements 10, 20 each comprise a third seismic mass with third mass webs, wherein the further bending springs comprise third bending spring elements and wherein the ratio between a third web width of the third mass webs and a further third web width of the third bending spring elements is equal to the ratio between the first web width and the further first web width.This results in the minimization of the dependence of the frequency dispersion on the edge loss in all spring-mass systems, such as the first detection mass element 11 with second coupling means 5, the second detection element 21 with further second coupling means 5, the first drive element 10 with third coupling means 4, and the second drive element 20 with further third coupling means 4. Furthermore, the design of the first and second detection mass elements 11, 21 as first and second rocker structures 11', 21' reduces both the vibration sensitivity of the micromechanical structure and the dependence of the frequency dispersion on the functional layer thickness.

[0023] In Fig. 5a and Fig. Figure 5 shows a schematic top view and a schematic side view of a micromechanical structure 1 according to a third embodiment of the present invention, wherein the third embodiment is essentially identical to that shown in the Fig. 4a and Fig. The second embodiment illustrated in Figure 4b is characterized in that the outer circumference 15 of the first detection mass element 11 (parallel to the main extension plane 100 in the rest position) is symmetrical with respect to the first torsion axis 13, and the second outer circumference 25 of the second detection mass element 21 (parallel to the main extension plane 100 in the rest position) is symmetrical with respect to the second torsion axis 23. This is achieved in each case by a first and second auxiliary frame 18, 28, which are arranged on the shorter side of the first and second rocker structure 11', 21', respectively.

[0024] In Fig. Figure 6 shows a schematic top view of a micromechanical structure 1 according to a fourth embodiment of the present invention, wherein the fourth embodiment is essentially identical to that shown in the Fig. 4a and Fig. The third embodiment shown in Figure 4b is characterized by the arrangement of a first and second additional web 19', 29' instead of the first and second additional frames 18, 28. In the rest position of the first and second rocker structure 11', 21', the first and second additional web 19', 29' are aligned parallel to the first direction X. The first coupling element 3 is attached at one end to the first additional web 19' and at the other end to the second additional web 29'.

[0025] In Fig. 7a and Fig. Figure 7b shows a schematic top view and a schematic side view of a micromechanical structure 1 according to a fifth embodiment of the present invention, wherein the fifth embodiment corresponds to that described in the Fig. 5a and Fig. 5b illustrated third embodiment, wherein the first rocker structure 11' is rotated 180 degrees along the first torsion axis 13, so that the shorter side of the first rocker structure 11, together with the first additional frame 17, is not facing the second rocker structure 21', but rather away from it. This results in the first and second deflections being, as shown in Fig. As shown in Figure 7b, the rotation vectors are not aligned but rather opposite to each other. That is, the rotation vector of the first rocker structure 11' is antiparallel to the rotation vector of the second rocker structure 21'. In this case, when rotation rates occur, the inward-facing sides of the first and second rocker structures 11' and 21' will move in the same direction, resulting in a symmetric detection mode in which the first coupling element 3 is not significantly loaded along the third direction Z. However, when linear acceleration occurs, the first and second rocker structures 11' and 21' move antisymmetrically, and the first coupling element 3 is loaded. The overall stiffness, and therefore also the frequency, of the antisymmetric linear acceleration mode is thus higher than that of the symmetric detection mode.

[0026] In Fig. Figure 8 shows a schematic top view of a micromechanical structure 1 according to a sixth embodiment of the present invention, wherein the sixth embodiment is essentially the same as that described in the Fig. 7a and Fig. The fifth embodiment illustrated in Figure 7b is characterized in that the first and second rocker structures 11', 21' are each rotated by 90 degrees parallel to the main extension plane 100, such that the first and second torsion axes 13, 13' are arranged on a common line 100' along the first direction X, and the first and second drive elements 10, 20 are open on one side parallel to the line 100'. The first and second coupling elements 3, 5 are arranged on this open side. The rotation of the first and second rocker structures 11', 21' has the advantage that deflection of the first and second rocker structures 11', 21' relative to the first and second drive elements 10, 20 along the first direction X, in particular by the first and second oscillation, is prevented.

[0027] In Fig. Figure 9 shows a schematic top view of a micromechanical structure 1 according to a seventh embodiment of the present invention, wherein the seventh embodiment is essentially the one described in Figure 9. Fig. The sixth embodiment is identical to the sixth embodiment illustrated in Figure 8, except that, in contrast to the sixth embodiment, the first and second rocker structure 11', 21' are arranged symmetrically to each other along the mirror plane 100" (similar to the second embodiment).

[0028] In Fig. Figure 10 shows a schematic top view of a micromechanical structure 1 according to an eighth embodiment of the present invention, wherein the eighth embodiment is essentially identical to that described in the Fig. 5a and Fig. The third embodiment, as illustrated in Figure 5b, is characterized in that the first and second drive elements 10, 20 are open on their facing sides, and the first and second detection mass elements 11, 21 are not directly connected to the substrate 2 by means of second coupling elements 5. Furthermore, the direction of the first and second vibrations 101, 201 is rotated by 90 degrees compared to the third embodiment, so that the first and second vibrations 101, 201 are no longer excited parallel to the first direction X, but parallel to the second direction Y, which is perpendicular to the first and third directions X, Z. In this case, the first and second comb drives 14, 24 are connected to the first and second drive elements 10, 20 along the second direction Y. The first and second vibrations 101, 201 thus run antiparallel to each other along the second direction Y.

[0029] In Fig. Figure 11 shows a schematic top view of a micromechanical structure 1 according to a ninth embodiment of the present invention, wherein the ninth embodiment is essentially identical to the Fig. The eighth embodiment illustrated in Figure 10 is characterized by the first rocker structure 11' being rotated by 180 degrees along the first torsion axis 13, so that the shorter side of the first rocker structure 11' together with the first additional frame 17 is not facing the second rocker structure 21', but rather away from the second rocker structure 21'.

[0030] In Fig. Figure 12 shows a schematic view of the change in the detection frequency as a function of the functional layer thickness of a micromechanical structure 1 according to the second embodiment of the present invention, with the functional layer thickness indicated on the abscissa 41 of the diagram and the relative frequency change on the ordinate 42. Curve 40 describes the change in the detection frequency as a function of the functional layer thickness, wherein the functional layer thickness comprises the thickness of the first detection mass element 11 perpendicular to the principal extension plane 100. It can be seen that, due to the design of the first detection mass element as a first rocker structure 11', the change in the functional layer thickness results in a comparatively small relative frequency change of the detection frequency with the functional layer thickness.

[0031] In Fig.Figure 13 shows a schematic view of the change in the detection frequency as a function of the edge loss of a micromechanical structure 1 according to the second embodiment of the present invention, with the edge loss plotted on the abscissa 51 of the diagram and the relative frequency change on the ordinate 52. The curve 50 thus shows the relative frequency change of the detection frequency of the micromechanical structure 1 as a function of the edge loss. It can be seen that the dependence of the change in the detection frequency on the edge loss is comparatively small. This is achieved because the ratio between the bending spring web width and the mass web width is approximately 3.24.

Claims

[1] Micromechanical structure (1), in particular a gyroscope, comprising a substrate (2) having a principal extension plane (100), a first detection mass element (11) and a second detection mass element (21), wherein the first detection mass element (11) is provided to be excitable by a first drive element (10) to a first vibration (101) parallel to the principal extension plane (100), wherein the second detection mass element (21) is provided to be excitable by a second drive element (20) to a second vibration (201) antiparallel to the first vibration (101), wherein a first Coriolis deflection of the first detection mass element (11) along a third direction (Z) perpendicular to the principal extension plane (100) is detectable by a first detection means,wherein a second Coriolis deflection of the second detection mass element (21) along the third direction (2) is detectable by a second detection means and wherein the first and the second detection mass element (11, 21) are provided to be coupled to each other by means of a first coupling element (3), characterized by, that the first detection mass element (11) is designed as a first rocker structure (11') and the second detection element (21) as a second rocker structure (21'), wherein the first and second rocker structure (11' and 21', respectively) is attached to the first and second drive element (10 and 20, respectively) by means of a first and second torsion spring (13 and 23, respectively), wherein the first and second torsion axis (13' and 23', respectively) of the first and second torsion spring (13, 23, respectively) is provided to run parallel to the first and second direction (X, Y, respectively), and the first and second rocker structure (11' and 21', respectively) has an asymmetric mass distribution with respect to the first and second torsion axis (13' and 23', respectively), wherein the first and / or the second torsion spring (13, 23) is designed as a ladder spring, wherein the first and / or the second Torsion spring (13, 23) are designed as a double conductor spring. [2] Micromechanical structure (1) according to claim 1, characterized by, that the first and / or the second torsion spring (13, 23) are designed as a multiple conductor spring. [3] Micromechanical structure (1) according to one of claims 1 or 2, characterized by , that the first and the second detection mass element (11, 21) are attached to the substrate (2) by means of second coupling elements (5), wherein the first and / or the second coupling elements (3, 5) in particular comprise bending springs which are preferably meander-shaped. [4] Micromechanical structure (1) according to any one of the preceding claims, characterized by , that the first and second drive elements (10, 20) are attached to the substrate (2) by means of third coupling elements (4), wherein the third coupling elements (4) in particular comprise further bending springs, which are preferably designed in a meander shape. [5] Micromechanical structure (1) according to any one of the preceding claims, characterized by, that the first and / or the second coupling elements (3, 5) are more compliant with respect to a deformation parallel to the first vibration (101) and / or parallel to the third direction (X, Z) than with respect to a deformation along a direction perpendicular to the first vibration (101) and to the third direction (Z). [6] Micromechanical structure (1) according to any one of the preceding claims, characterized by , that the first drive element (10) is formed to substantially completely surround the first detection mass element (11) parallel to the main extension plane (100) and / or the second drive element (20) is formed to substantially completely surround the second detection element (21) parallel to the main extension plane (100), wherein the first and / or the second detection element (11, 21) each have only one opening (11", 21") for the first and / or the second coupling elements (3, 5). [7] Micromechanical structure (1) according to any one of the preceding claims, characterized by, that the outer circumference (15) of the first detection mass element (11) with respect to the first torsion axis (13) and the outer circumference (25) of the second detection mass element (21) with respect to the second torsion axis (23) are each symmetrical. [8] Micromechanical structure (1) according to any one of the preceding claims, characterized by , that the first and / or the second detection mass element (11, 21) comprises a second seismic mass with second mass webs, wherein the bending springs comprise second bending spring elements and wherein the ratio between a second web width of the second mass webs and a further second web width of the second bending spring elements is equal to the ratio between the first web width (205) and the further first web width (206).

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