Micromechanical component and method for manufacturing a micromechanical component

A micromechanical component, whose diaphragm is supported and has support structures on its inner diaphragm side. Each of the support structures includes a first and second edge element structure, and at least one intermediate element structure positioned between the first and second edge element structures. For each of the support structures, a plane of symmetry is definable, with respect to which at least the first edge element structure of the respective support structure and the second edge element structure of the respective support structure are specularly symmetric. In each of support structures, a first maximum dimension of its first edge element structure perpendicular to its plane of symmetry and a second maximum dimension of its second edge element structure perpendicular to its plane of symmetry are greater than the maximum dimension of its intermediate element structure perpendicular to its plane of symmetry.

FIELD

The present invention relates to a micromechanical component and a capacitive pressure sensor device. The present invention relates to a method for manufacturing a micromechanical component, as well.

BACKGROUND INFORMATION

German Patent Application No. DE 10 2009 000 403 A1 describes a capacitive pressure sensor that includes a substrate and a diaphragm, which spans a cavity situated between the diaphragm and an upper surface of the substrate. The diaphragm is supported by at least a frame structure, so as to be set apart from the bottom side of the cavity.

SUMMARY

The present invention provides a micromechanical component, a capacitive pressure sensor device, and a method for manufacturing a micromechanical component.

An example embodiment of the present invention provides support structures on an inner diaphragm side of a diaphragm spanning a cavity; the support structures being formed in such a manner, that when the diaphragm is deflected into the cavity and/or bulges out of the cavity, the mechanical stresses occurring directly at the support structures in the diaphragm are spread over a wider area in comparison with the related art. Thus, compared to conventional structures formed on an inner diaphragm side, damage to the diaphragm, such as, in particular, rupturing of the diaphragm, is to be feared less often. Therefore, the present invention contributes towards providing micromechanical components and/or capacitive pressure sensor devices equipped with them, which have a longer service life and/or a higher maximum load than the related art.

In one advantageous specific embodiment of the micromechanical component in accordance with the present invention, the support structures extending from the inner diaphragm side to the bottom side of the cavity are each situated adjacent to a self-supporting region of the diaphragm in such a manner, that in each of the support structures, the adjacent, self-supporting region lies on a side of its first edge element structure pointed away from its at least one intermediate element structure. Due to the advantageous designs/layouts of the support structures extending from the inner diaphragm side to the bottom side of the cavity, in particular, on the basis of their first edge element structures, a high local intensity of mechanical stresses, which could result in damage to the diaphragm, is prevented from occurring in the case of such an orientation of the support structures in the specific boundary region between each of the support structures and the adjacent, self-supporting region.

In particular, at least one of the support structures extending from the inner diaphragm side to the bottom side of the cavity may be positioned adjacent to an outer region of the diaphragm in such a manner, that in the at least one support structure, the adjacent outer region lies on a side of its second edge element structure pointed away from its at least one intermediate element structure. In this case, the boundary region, which is between the at least one support structure positioned in such a manner and the adjacent outer region and is normally highly susceptible to mechanical stresses, is also protected more effectively from possible rupturing of the diaphragm.

Alternatively, or in addition, at least a first of the support structures extending from the inner diaphragm side to the measuring electrode and a second of the support structures extending from the inner diaphragm side to the measuring electrode may be placed in position relative to each other in such a manner, that their second edge element structures are pointed towards each other; a support wall structure extending from the bottom side of the cavity to the inner diaphragm side being formed between their second edge element structures. Consequently, the support structures extending from the inner diaphragm side to the measuring electrode may also be combined to form a comparatively large/large-area overhead suspension of the measuring electrode.

In one further advantageous specific embodiment of the micromechanical component in accordance with the present invention, in at least one of the support structures, its at least one intermediate element structure is connected to its first edge element structure and/or to its second edge element structure. Thus, the at least one intermediate element structure and at least one of the associated edge element structures may form a compact/one-piece overall structure. Alternatively, the at least one support structure and the two associated edge element structures may also be spatially separated from each other.

For example, in at least one of the support structures, its two intermediate element structures may be connected to its first edge element structure and to its second edge element structure in such a manner, that its two intermediate element structures, its first edge element structure, and its second edge element structure frame a hollow space extending from the bottom side of the cavity to the inner diaphragm side. Thus, an “overall circumference” of the hollow-space framing made up of the two intermediate element structures, the first frame element structure and the second frame element structure may be used as a surface of action of mechanical stresses, in order to prevent damage to/a rupture of the diaphragm.

The at least one support structure, whose two intermediate element structures, whose first edge element structure, and whose second edge element structure frame the respective hollow space, may optionally be designed to have at least two round outer edges. Consequently, a local occurrence of mechanical stresses at a sharp outer edge may be prevented.

The cavity is preferably sealed so air-tightly to have a reference pressure present in it, that the diaphragm may be deformed at least partially with the aid of a physical pressure unequal to the reference pressure, on an outer diaphragm side of the diaphragm pointed away from the cavity; a counter-electrode situated on the bottom side of the cavity, and the measuring electrode, being electrically contactable in such a manner, that a voltage applied between the counter-electrode and the measuring electrode may be tapped off. Therefore, the micromechanical component described here may be used advantageously for measuring the physical pressure prevailing, in each instance, on the outer diaphragm side, in that a measured value regarding the physical pressure is determined in view of the voltage tapped off between the counter-electrode and the measuring electrode.

The advantages of the micromechanical component described in the preceding paragraph are also provided in a capacitive pressure sensor device having such a micromechanical component, and in evaluation electronics, which are configured to determine and output a measured value regarding the physical pressure prevailing, in each instance, on the outer diaphragm side, in view of at least the voltage tapped off between the counter-electrode and the measuring electrode.

In addition, the execution of a corresponding method for manufacturing a micromechanical component in accordance with the present invention provides the advantages explained above. In particular, it is emphasized that the manufacturing method according to the specific embodiments of the micromechanical component explained above may be refined further.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG.1athrough1cshow schematic representations of a first specific embodiment of the micromechanical component, in accordance with the present invention.

The micromechanical component schematically represented inFIG.1athrough1cincludes a substrate10having an upper substrate surface10a. Substrate10is preferably a semiconductor substrate, such as, in particular, a silicon substrate. However, it should be pointed out that instead of, or in addition to, silicon, substrate10may also include at least one further semiconductor material, at least one metal, and/or at least one electrically insulating material.

The micromechanical component also includes a diaphragm12, which spans a cavity14lying between diaphragm12and upper substrate surface10a, so as to be set apart from a bottom side14aof cavity14pointed away from diaphragm12. However, the position of cavity14between diaphragm12and upper substrate surface10adoes not have to be understood to mean that bottom side14aof cavity14borders directly on upper substrate surface10a. Instead, at least one more layer16and18, such as at least one insulating layer16and18, which covers upper substrate surface10aat least partially, may be situated between bottom side14aof cavity14and upper substrate surface10aof substrate10. In particular, the at least one insulating layer16and18may be a silicon oxide layer and/or a (silicon-rich) silicon nitride layer.

The micromechanical component also includes a plurality of support structures20aand20b, which each extend from an inner diaphragm side12aof diaphragm12to bottom side14aof cavity14and/or from inner diaphragm side12ato a measuring electrode28suspended on diaphragm12. Inner diaphragm side12ais to be understood as a side of diaphragm12oriented towards substrate10. Support structures20aand20bmay gradually change, in particular, into diaphragm12, which means that inner diaphragm side12amay also be understood as a “virtual boundary plane,” which is situated at a distance from an outer diaphragm side12bpointed away from substrate10; the distance being equal to a minimum layer thickness dminof diaphragm12perpendicular to upper substrate surface10a. Diaphragm12is held apart from bottom side14aof cavity14with the aid of at least the first support structures20aextending from inner diaphragm side12aof diaphragm12to bottom side14aof cavity14. The second support structures20bextending from inner diaphragm side12ato measuring electrode28are used for “electrode suspension.” Each of support structures20aand20bis joined separately to diaphragm12. In the same way, each of first support structures20ais anchored separately to bottom side14aof cavity14, and each of second support structures20bis anchored separately to measuring electrode28.

In the specific embodiment ofFIG.1athrough1c, cavity14is sealed, for example, in an air-tight manner. To that end, for example, a frame structure22, which is not discussed here in further detail, may seal cavity14in such an air-tight manner, that a reference pressure p0is enclosed in cavity14. Therefore, as is apparent inFIG.1b, at least one self-supporting region24of diaphragm12is deformable with the aid of a physical pressure p on outer diaphragm side12bunequal to reference pressure p0. The deformation of at least self-supporting region24of diaphragm12due to the physical pressure p unequal to reference pressure p0acting upon it is detectable, by tapping off a voltage between a counter-electrode26situated on bottom side14aof cavity14, and measuring electrode28. To that end, counter-electrode26and measuring electrode28are electrically contactable in such a manner, that the voltage applied between counter-electrode26and measuring electrode28may be tapped off. Subsequently, a measured value regarding the physical pressure p prevailing, in each instance, on outer diaphragm side12bmay be determined in view of at least the tapped-off voltage. Consequently, the micromechanical component ofFIG.1athrough1cmay advantageously be used as at least part of a capacitive pressure sensor device. However, it is emphasized that the usefulness of the micromechanical components explained in light of the figures described here and subsequent figures is not limited to capacitive sensor devices.

As is apparent inFIG.1b, in response to deformation of at least self-supporting region24of diaphragm12, mechanical stresses occur in the specific “inner” boundary region30abetween each of first support structures20aand self-supporting region24. In the same way, in response to deformation of at least self-supporting region24of diaphragm12, mechanical stresses may also occur in the specific “outer” boundary region30bbetween each of first support structures20aand an outer region of diaphragm12, such as an edge of the diaphragm at frame structure22. In response to deformation of at least self-supporting region24of diaphragm12, mechanical stresses may also occur in the specific “outer” electrode-suspension boundary region31adjacent to each of second support structures20b. However, as explained in more detail below, the risk of damage to diaphragm12due to mechanical stresses, in particular, the risk of rupturing diaphragm12due to mechanical stresses, may be reduced significantly with the aid of an advantageous design of support structures20aand20b.

In the micromechanical component, each of the first and second support structures20aand20bis configured with, in each instance, a first edge element structure32, a second edge element structure34, and at least one intermediate element structure36situated between associated, first edge element structure32and associated second edge element structure34.FIG.1cshows an example of one of first support structures20a; the substructures32through36of each first support structure20aeach extending from inner diaphragm side12aof diaphragm12to bottom side14aof cavity14. However, it is emphasized here that second support structures20bmay also include the features described below; in this case, substructures32through36of each second support structure20beach extending from inner diaphragm side12aof diaphragm12to measuring electrode28.

In each instance, a plane of symmetry38, with respect to which at least first edge element structure32of respective support structure20aor20band second edge element structure34of respective support structure20aor20bare specularly (mirror) symmetric, may be defined for each of support structures20aand20b. As an option, the at least one intermediate element structure36may also be formed specularly symmetrically with respect to plane of symmetry38. Plane of symmetry38intersects bottom side14aof cavity14and inner diaphragm side12aof diaphragm12. In particular, plane of symmetry38may be oriented perpendicularly to upper substrate surface10aof substrate10.

In addition, in each of support structures20aand20b, a first maximum dimension a1of its first edge element structure32perpendicular to its plane of symmetry38and a second maximum dimension a2of its second edge element structure34perpendicular to its plane of symmetry38are each greater than the at least one respective maximum dimension a3of its at least one intermediate element structure36perpendicular to its plane of symmetry38. Therefore, in each of support structures20aand20b, a linear length of a boundary of its contact region/anchoring region with diaphragm12(on inner diaphragm side12a) is increased markedly in comparison with the related art, due to the design of the support structures20aand20bdescribed here. Thus, each of support structures20aand20bprovides markedly more “surface of action” to mechanical stresses, which occur in diaphragm12, adjacent to respective support structure20aor20b, which means that the mechanical stresses are reduced and consequently result less often in damage to diaphragm12, in particular, result less often in rupturing of diaphragm12. First maximum dimension a1of respective, first edge element structure32of each of support structures20aand20band/or second maximum dimension a2of respective, second edge element structure34of each of support structures20aand20bare preferably in a range of 2 μm (micrometers) to 20 μm (micrometers). Specific, maximum dimension a3of the at least one intermediate element structure36of each of support structures20aand20bmay be, e.g., in a range of 0.5 μm (micrometers) to 2 μm (micrometers).

First support structures20aare advantageously situated, in each instance, adjacent to self-supporting region24of diaphragm12in such a manner, that in each of first support structures20a, adjacent, self-supporting region24lies on a side of its first edge element structure32pointed away from its at least one intermediate element structure36. Thus, the comparatively large, first maximum dimension a1of first edge element structure32ensures a comparatively long face/end face of respective, first support structure20a, which is oriented towards self-supporting region24of diaphragm12. Consequently, the mechanical stresses occurring in specific “inner” boundary region30aare spread out over a comparatively large “surface of action,” which means that a local intensity of the mechanical stresses on the side of first edge element structure32pointed away from its at least one intermediate element structure36remains comparatively low.

In addition, at least one of the first support structures20ais situated adjacent to an outer region of diaphragm12, such as the diaphragm edge on frame structure22, in such a manner, that in the at least one first support structure20a, the adjacent outer region lies on a side of its second edge element structure34pointed away from its at least one intermediate element structure36. Thus, due to its comparatively large, second dimension a2perpendicular to plane of symmetry38, second edge element structure34also provides a comparatively large face/end face for a mechanical stress occurring in the “outer” boundary region30bbetween the outer region of diaphragm12and respective support element20a. Therefore, a local intensity of mechanical stresses in “outer” boundary region30bbetween the outer region of diaphragm12and the at least one support structure20aremains comparatively low.

An advantageous orientation of second support structures20bis discussed below in detail.

As is apparent inFIG.1c, in at least one of the first and second support structures20aand20b, its at least one intermediate element structure36may be connected to its first edge element structure32and/or to its second edge element structure34. In the specific embodiment ofFIG.1athrough1c, the (single) intermediate element structure36is connected to the two edge element structures32and34. Alternatively, however, the at least one intermediate element structure36and the two associated edge element structures32and34may also be separated/separate from one another (see, for example,FIG.2). In the specific embodiment ofFIG.1athrough1c, each first edge element structure32of support structures20aand20bis, in each instance, a right parallelepiped extending perpendicularly to plane of symmetry38with first maximum dimension a1. Accordingly, each second edge element structure34of support structures20aand20bis also, in each instance, a right parallelepiped extending perpendicularly to plane of symmetry38with second maximum dimension a2. In contrast, the (single) intermediate element structure36is a right parallelepiped, which extends along plane of symmetry38, is specularly symmetric with respect of plane of symmetry38, and whose maximum dimension a3perpendicular to plane of symmetry38is markedly less than its dimensions within plane of symmetry38. Consequently, support structures20aand20beach have a cross section in the shape of an “I” (capital letter I) in a plane oriented parallelly to upper substrate surface10aof substrate10.

FIG.2throughFIG.15show schematic representations of further specific embodiments of the micromechanical component.

The micromechanical components represented schematically with the aid ofFIG.2throughFIG.15include many of the features of the specific embodiment explained above. Therefore, in the following, only the differences between the micromechanical components ofFIG.2throughFIG.15and the specific embodiment ofFIG.1athrough1care discussed. If not described differently, the micromechanical components ofFIG.2throughFIG.15may also include the features of the specific embodiment explained above.

In the micromechanical component represented schematically with the aid ofFIG.2, support structures20aand20bdiffer from those of the specific embodiment described above only in that in each instance, there is a first gap40abetween the (single) intermediate element structure36and first edge element structure32of the same support structure20aor20b, and a second gap40bbetween the (single) intermediate element structure36and second edge element structure34of the same support structure20aor20b. Thus, the specific substructures32through36of each support structure20aand20bare separate/separated from each other.

On the micromechanical component represented schematically with the aid ofFIG.3, in the case of at least one of support structures20aand20b, its two intermediate element structures36aand36bare connected to its first edge element structure32and to its second edge element structure34in such a manner, that its two intermediate element structures36a,36b, its first edge element structure32, and its second edge element structure34frame a hollow space42extending from bottom side14aof cavity14to inner diaphragm side12a. The design of specific support structure20aor20bas hollow-space framing44bordering the respective hollow space42contributes to the increase in the linear length of the boundary of its contact region/anchoring region on diaphragm12. Accordingly, the support structure20aor20btaking the form of hollow-space framing44provides mechanical stresses even more “surface of action,” which means that a local intensity of the mechanical stresses occurring at the specific support structure20aor20bis reduced significantly. Hollow-space framing44is preferably specularly symmetric with respect to plane of symmetry38.

As is apparent inFIG.4, the at least one support structure20aor20b, whose two intermediate element structures36aand36b, whose first edge element structure32, and whose second edge element structure34frame respective hollow space42, may be designed to have at least two round outer edges46. In the micromechanical component ofFIG.4, for example, round outer edges46are formed on the side of its second edge element structure34pointing away from intermediate element structures34.

In contrast, the micromechanical component ofFIG.5includes at least one support structure20aand20b, which takes the form of hollow-space framing44, and in which round outer edges46are formed on the side of first edge element structure32pointed away from intermediate element structures36aand36b. The micromechanical component ofFIG.6includes at least one support structure20aand20bhaving four round outer edges46; in each instance, two round outer edges46being formed on the side of first edge element structure32pointed away from intermediate element structures36aand36b, and on the side of second edge element structure34pointed away from intermediate element structures36aand36b. Thus, in a plane oriented parallelly to upper substrate surface10aof substrate10, at least one of support structures20aand20bof the micromechanical component ofFIG.6has a cross section in the shape of a rounded-off rectangle.

The specific embodiments described in the following are advantageously suitable, in particular, as second support structures20b. In this case, second support structures20bare preferably oriented in such a manner, that the adjacent “outer” electrode suspension boundary region31is on a side of its first edge element structure32pointing away from its at least one intermediate element structure36. Due to its comparatively large, first dimension a1perpendicular to plane of symmetry38, first edge element structure32provides a comparatively large face/end face to a mechanical stress occurring in “outer” electrode suspension boundary region31. Therefore, a local intensity of mechanical stresses occurring in “outer” electrode suspension boundary region31also remains comparatively low.

In the micromechanical component schematically represented with the aid ofFIG.7, (at least) second support structures20beach take the form of hollow-space framing44. However, in a spatial direction oriented parallelly to upper substrate surface10a, within plane of symmetry38, intermediate element structures36aand36bhave a length L36, which is markedly greater than first maximum dimension a1of its first edge element structure32perpendicular to its plane of symmetry38and second maximum dimension a2of its second edge element structure34perpendicular to its plane of symmetry38. Length L36of intermediate element structures36aand36bin the spatial direction oriented parallelly to upper substrate surface10awithin plane of symmetry38may be, for example, greater than or equal to 5 μm (micrometers), in particular, greater than or equal to 10 μm (micrometers).

The support structure20bschematically represented inFIG.8only differs from that shown inFIG.7, in that a first intermediate element structure36aconnected to first edge element structure32is spaced apart from second edge element structure34by a first gap48a, while a second intermediate element structure36bconnected to second edge element structure34is spaced apart from first edge element structure32by a second gap48b.

In a plane oriented parallelly to substrate surface10aof substrate10, each of support structures20brepresented inFIGS.9and10also has a cross section in the shape of an “I” (capital letter I). In contrast to the specific embodiments ofFIGS.1cand2, in a spatial direction oriented parallelly to upper substrate surface10a, within plane of symmetry38, the (single) intermediate element structure36has a length L36, which is markedly greater than first maximum dimension a1of adjacent, first edge element structure32perpendicular to its plane of symmetry38, and markedly greater than second maximum dimension a2of adjacent second edge element structure34perpendicular to its plane of symmetry38. In contrast to the specific embodiment ofFIG.10,FIG.9shows a support structure20b, in which in each instance, a first gap40ais situated between the (single) intermediate element structure36and first edge element structure32of the same support structure20b, and a second gap40bis situated between the (single) intermediate element structure36and second edge element structure34of the same support structure20b.

As is shown inFIGS.11and12, first edge element structure32and second edge element structure34of each support structure20aand20bmay each be formed in the shape of a (right) prism, as well. In this case, a dimension of the specific (right) prism perpendicular to plane of symmetry38decreases in the direction of the (single) intermediate element structure36of respective support structure20aor20b. In this case, as well, a first gap50amay optionally be formed between first edge element structure32and the (single) intermediate element structure36of the same support structure20aor20b, and a second gap50bmay optionally be formed between second edge element structure34and the (single) intermediate element structure36of the same support structure20aor20b(seeFIG.12).

Support structure20brepresented schematically with the aid ofFIG.13includes a first edge element structure having a protuberance on its side pointing away from the (single) intermediate element structure36of same support structure20b. Therefore, first edge element structure32includes a right parallelepiped having a spherical segment formed on the side pointing away from the (single) intermediate element structure36of the same support structure20b. Therefore, first edge element structure32is formed in the “shape of a head of a nail.” This shape of first edge element structure32also contributes towards further increasing its “surface of action” for mechanical stress and consequently reduces the risk of a rupture of diaphragm12directly on respective support structure20aor20b. As an option, second edge element structure34of the same support structure20aor20bmay be formed in the “shape of the head of a nail,” in that second edge element structure34includes a right parallel piped having a spherical segment on the side pointed away from the (single) intermediate element structure36of the same support structure20aor20b. Edge element structures32and34may also be separated from the (single) intermediate element structure36of the same support structure20aor20b(by at least a gap).

In the micromechanical components schematically represented with the aid ofFIGS.14and15, at least one of the second support structures20band another of the second support structures20bare oriented with respect to each other in such a manner, that their second edge element structures34are aligned with each other; a support wall structure52extending from bottom side14aof cavity14to inner diaphragm side12abeing formed between their second edge element structures. In a direction oriented parallelly to upper substrate surface10a, within plane of symmetry38, support wall structure52preferably has a length L52, which is markedly greater than first maximum dimension a1and second maximum dimension a2. Length L52of support wall structure52in the spatial direction oriented parallelly to upper substrate surface10a, within plane of symmetry38, may be, for example, greater than or equal to 10 μm (micrometers), in particular, greater than or equal to 15 μm (micrometers). Support wall structure52may optionally be connected to at least one of adjacent support structures20b(FIG.14). Alternatively, a first gap54amay be situated between adjacent support structure20band support wall structure52, and a second gap54bmay be situated between further, adjacent support structure20band support wall structure52.

Regarding further characteristics and features of the micromechanical components schematically represented byFIG.2through15, reference is made to the specific embodiment ofFIG.1athrough1c.

The above-described shapes of support structures20aand20bmay also be “combined” with each other in such a manner, that a micromechanical component has different shapes of support structures20aand20b.

In comparison with the related art, all of the support structures20aand20bdescribed above provide an increase in their linear length of the boundary of their region of contact/anchoring with diaphragm12(on the inner diaphragm side12a). In other words, this may also be referred to as an increase in the linear length for contacting the diaphragm. By increasing the linear length for the contacting of the diaphragm by support elements20, a local intensity of the mechanical stresses at the boundary of their region of contact with/anchoring to diaphragm12is reduced. In this manner, a risk of forming a rupture in diaphragm12is reduced in comparison with the related art. Support structures20aand20bmay also include at least two intermediate element structures36,36aor36bpositioned in a row oriented along or parallelly to plane of symmetry38.

The micromechanical components described above may each be used in a capacitive pressure sensor device. In addition, the capacitive pressure sensor device preferably includes evaluation electronics, which are configured to determine and output a measured value regarding the physical pressure p prevailing, in each instance, on outer diaphragm side12b, in view of at least the voltage tapped off between counter-electrode26and measuring electrode28.

FIG.16shows a flow chart for explaining a specific embodiment of the method for manufacturing a micromechanical component.

The manufacturing method includes at least one method step S1, in which, on a substrate having an upper substrate surface, a diaphragm is stretched out in such a manner, that the diaphragm spans a cavity situated between the diaphragm and the upper substrate surface, so as to be spaced apart from a bottom side of the cavity pointing away from the diaphragm. In a method step S2, a plurality of support structures are formed, which each extend from an inner diaphragm side12aof the diaphragm to the bottom side of the cavity and/or from the inner diaphragm side to a measuring electrode suspended on the diaphragm. Method step S2may be executed simultaneously to, or temporally overlapping with, method step S1. Method step S2may also be executed before or after method step S1.

In addition, each of the support structures is formed to have, in each instance, a first edge element structure, a second edge element structure, and at least one intermediate element structure situated between the associated, first edge element structure and the associated, second edge element structure, so that for each of the support structures, in each instance, a plane of symmetry is definable, with respect to which at least the first edge element structure of the respective support structure and the second edge element structure of the respective support structure are specularly symmetric. In addition, in each instance, the substructures of each of the support structures are formed in such a manner, that in each of the support structures, a first maximum dimension of its first edge element structure perpendicular to its plane of symmetry and a second maximum dimension of its second edge element structure perpendicular to its plane of symmetry are greater than the at least one maximum dimension of its at least one intermediate element structure perpendicular to its plane of symmetry.