DE102017200055A1 - MEMS sensor device and method for manufacturing a MEMS sensor device - Google Patents

Abstract

The invention provides a MEMS sensor device and a method for manufacturing a MEMS sensor device. The MEMS sensor device (110) is formed with: a piezoelectric sensor structure (114); wherein the piezoelectric sensor structure (114) comprises a number of first portions (111) disposed within a first virtual plane or layer (E1), and wherein the piezoelectric sensor structure (114) has a number of second portions (112) within a second virtual plane or layer (E2) or crossing a second virtual plane or layer (E2); wherein the first virtual plane or layer (E1) and the second virtual plane or layer (E2) are different from each other and arranged parallel to each other.

Description

The present invention relates to a microelectromechanical sensor device (MEMS sensor device) and a method for manufacturing a MEMS sensor device. The MEMS sensor device may in particular be a microelectromechanical pressure sensor device, preferably a microelectromechanical microphone.

State of the art

Microelectromechanical (MEMS) sensor devices are needed for a variety of applications, such as microphones in mobile devices such as smartphones. Conventional micro-electro-mechanical microphones are either capacitive microphones or use piezoelectric structures. Piezoelectric structures are structures to which deformation, e.g. during an expansion or compression, an electrical voltage is created. Intrinsic deformations of a piezoelectric structure from a rest position, e.g. due to the clamping of the piezoelectric structure in the sensor device, can affect the accuracy of the sensor device.

Conventional piezoelectric structures have two or more piezoelectric layers bonded together. Thus, by applying pressure to such a piezoelectric structure, such as by sound, the differential deformation of the two or more interconnected piezoelectric layers can provide an effective, non-zero voltage to the piezoelectric structure which can act as a sensor signal.

In the US 2014/0339657 A1 is a MEMS microphone having a plurality of interconnected piezoelectric layers described.

Disclosure of the invention

The present invention discloses a micromechanical sensor device having the features of patent claim 1, a manufacturing method having the features of patent claim 10 and a manufacturing method having the features of patent claim 11.

Accordingly, a microelectromechanical sensor device having a piezoelectric sensor structure is provided. In particular, the piezoelectric sensor structure comprises a piezoelectric material or consists of a piezoelectric material. As piezoelectric materials, for example, piezoelectric ceramics and / or piezoelectric crystals come into question. The piezoelectric material may, for example, be or have in particular PZT (lead zirconium titanate) or AlN (aluminum nitride). The piezoelectric sensor structure is preferably formed in one piece and connected.

The piezoelectric sensor structure has a number of first portions which are within a first virtual, i. imaginary, level or layer are arranged. The piezoelectric sensor structure also has a number of second portions which are within a second virtual, i. imaginary, layer or layer are arranged or cross a second virtual layer or layer. The first virtual plane or layer and the second virtual plane or layer are different from each other and arranged parallel to each other. The first virtual plane or layer and the second virtual plane or layer may be spaced apart from each other by a non-fading pitch.

It should be understood that said arrangement of the first and second portions with respect to the first and second virtual plane or layer is related to a rest position of the sensor structure. In a proper use of the sensor device in which the sensor structure is subjected to deformations, deviations may occur. Although the sections of the sensor structure have a finite thickness, in the foregoing and in the following, some are also referred to as planes, in particular because the sections preferably have a small thickness compared to their lateral dimensions.

The number of first and / or second portions may be a number of one or a plurality, e.g. to act two, three or more first or second sections. A second section, in each case exactly one second section, is preferably arranged, directly or indirectly, between every two first sections. Also preferably, directly or indirectly, between each two second sections each have a first section, in particular each exactly a first section, respectively.

The first and second portions may be connected to each other, exclusively or partially, directly or directly, within the piezoelectric sensor structure. In other words, it can be provided that each of the first sections is directly connected to at least one of the second sections. But it can also be provided that each of the first sections, each with at least one of the second Sections indirectly, for example via a respective third section, is connected, wherein the respective third section may extend in particular between the first virtual layer or layer and the second virtual layer or layer.

Likewise, it may additionally or alternatively be provided that each of the second sections is directly connected to at least one of the first sections. However, it can also be provided that each of the second sections, each with at least one of the first sections indirectly, e.g. via a respective third section, wherein the respective third section may extend in particular between the first virtual plane or layer and the second virtual plane or layer.

Preferably, between each two first sections are each arranged, in this order, one of the third sections, one of the second sections, and another of the third sections. Also preferably, between each two second sections are each arranged, in this order, one of the third sections, one of the first sections, and another of the third sections.

In its cross section, the piezoelectric sensor structure of the function curve of a symmetric or asymmetric periodic rectangular function or the function curve of a periodic delta function same. By a symmetric periodic rectangular function is meant a rectangular function in which a respective portion of contiguous non-zero function values is as wide as a respective portion of contiguous function values equal to zero. By an asymmetric periodic rectangular function is meant a rectangular function in which a respective non-zero portion of contiguous function values has a different width than a respective portion of contiguous function values equal to zero, in particular narrower.

The virtual layer or layer may be a flat layer, i. a layer without curvature act. However, the layer can also, in particular due to manufacturing inaccuracies, have one or more curvatures.

In addition, a method for manufacturing a microelectromechanical sensor device is provided. The method comprises at least the steps: forming at least one depression and / or at least one elevation in or on a surface of a substrate; Depositing a sacrificial layer on the substrate and the at least one depression and / or at least one elevation; Forming a piezoelectric layer on the sacrificial layer at least in the region of the at least one depression and / or at least one elevation; and partially removing the substrate and sacrificial layer to partially expose the piezoelectric layer.

Advantages of the invention

One finding underlying the present invention is that a single piezoelectric structure - instead of a plurality of interconnected piezoelectric layers - may be sufficient for a sensor device if this piezoelectric structure is designed according to the invention.

By avoiding two or more piezoelectric layers bonded together, intrinsic deformations of the two or more layers due to their bonding can be avoided. Thus, a more precise sensor device can be provided.

Furthermore, by forming a single piezoelectric structure, a need for piezoelectric material can be reduced. For example, if instead of two piezoelectric layers only a single piezoelectric layer is used in the piezoelectric sensor structure, 50% of piezoelectric material can be saved with the same layer thickness. With the saving of material also results in a weight reduction of the MEMS sensor device, which can also be accompanied by an increased resonant frequency, which in turn can have an improved sensor performance of the sensor device result.

The targeted shaping of the first and second sections of the piezoelectric sensor structure makes the MEMS sensor device particularly versatile and adaptable for a wide variety of applications. The microelectromechanical sensor device can be optimized in particular with regard to a sensitivity or a stress gradient.

Advantageous embodiments and further developments emerge from the dependent claims and from the description with reference to the figures.

According to a preferred development, the first sections and the second sections are formed in a direction parallel to the first and / or the second virtual plane or layer having a same width. The sequence of the first and second sections can thus be periodic. Thus, a uniformly resilient and sensitive sensor structure can be provided.

According to a further preferred development, the first sections and the second sections are formed in a direction parallel to the first and / or the second virtual plane or layer having different widths. The sensor structure is thus versatile adaptable.

According to a further preferred development, adjacent first sections and second sections of the piezoelectric sensor structure partially overlap each other, in particular in a direction parallel to the first and the second virtual plane or layer. Thus, the piezoelectric sensor structure can be produced with little effort and designed to be particularly robust and space-saving.

According to a further preferred development, the microelectromechanical sensor device comprises a frame device on which the piezoelectric sensor structure is suspended. In some variants, the piezoelectric sensor structure may be suspended from the frame means at one end of the piezoelectric sensor structure. In this way, a mobility of the sensor structure and thus a sensitivity of the sensor device can be increased. In some other variants, the sensor structure may be suspended from the frame structure at two ends of the sensor structure. Thus, the sensor structure can be fastened particularly stable and robust. Under one end of the sensor structure, in particular, a lateral end, i. a conclusion of the sensor structure in a direction parallel to the first and the second plane or layer are understood. One, two, several, or all ends of the sensor structure may be formed by one of the first and / or one of the second sections.

According to a further preferred refinement, in each case a first electrode and a second electrode are arranged both at the first sections, and in each case a first electrode and a second electrode are arranged at the second sections. In some embodiments, the first electrodes are arranged on a first side of the sensor structure and the second electrodes on the second portions and on a second side of the sensor structure on the first portions the second electrodes and on the second portions of the first electrodes. In this way, e.g. upon complete deformation of the sensor structure, all first electrodes act as cathodes and all second electrodes act as anodes or vice versa.

In particular, two different halves of the space should be understood by the first and the second side, into which the three-dimensional space is subdivided by the first and / or second virtual plane or layer of the sensor structure.

In other embodiments, both the first electrodes and the second electrodes may be disposed only at the first portions.

According to a further preferred refinement, the sensor device comprises an evaluation device which is electrically connected to the first electrodes and the second electrodes and which is designed to generate a sensor signal based on one or more voltages between the first electrodes on the one hand and the second electrodes on the other hand to generate and output.

list of figures

• 1 eine schematische Querschnittsansicht durch eine mikroelektromechanische Sensorvorrichtung gemäß einer Ausführungsform der vorliegenden Erfindung;
• 2 eine schematische Querschnittsansicht durch eine mikroelektromechanische Sensorvorrichtung gemäß einer weiteren Ausführungsform der vorliegenden Erfindung;
• 3 eine schematische Querschnittsansicht durch eine mikroelektromechanische Sensorvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung;
• 4 eine schematische Querschnittsansicht durch eine mikroelektromechanische Sensorvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung;
• 5 eine schematische Querschnittsansicht durch eine mikroelektromechanische Sensorvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung;
• 6 ein schematisches Flussdiagramm zum Erläutern eines Verfahrens zum Herstellen einer mikroelektromechanischen Sensorvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung;
• 7 schematische Querschnittsansichten einer in der Herstellung befindlichen mikroelektromechanischen Sensorvorrichtung nach dem Verfahren gemäß 6;
• 8 ein schematisches Flussdiagramm zum Erläutern eines Verfahrens zum Herstellen einer mikroelektromechanischen Sensorvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung;
• 9 schematische Querschnittsansichten einer in der Herstellung befindlichen mikroelektromechanischen Sensorvorrichtung nach dem Verfahren gemäß 8; und
• 10 ein schematisches Flussdiagramm zum Erläutern eines Verfahrens zum Herstellen einer mikroelektromechanischen Sensorvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung.

The present invention will be explained in more detail with reference to the embodiments illustrated in the schematic figures of the drawings. Show it:

• 1 a schematic cross-sectional view through a microelectromechanical sensor device according to an embodiment of the present invention;
• 2 a schematic cross-sectional view through a microelectromechanical sensor device according to another embodiment of the present invention;
• 3 a schematic cross-sectional view through a microelectromechanical A sensor device according to still another embodiment of the present invention;
• 4 a schematic cross-sectional view through a microelectromechanical sensor device according to yet another embodiment of the present invention;
• 5 a schematic cross-sectional view through a microelectromechanical sensor device according to yet another embodiment of the present invention;
• 6 a schematic flowchart for explaining a method of manufacturing a microelectromechanical sensor device according to yet another embodiment of the present invention;
• 7 schematic cross-sectional views of a manufacturing microelectromechanical sensor device according to the method according to 6 ;
• 8th a schematic flowchart for explaining a method of manufacturing a microelectromechanical sensor device according to yet another embodiment of the present invention;
• 9 schematic cross-sectional views of a manufacturing microelectromechanical sensor device according to the method according to 8th ; and
• 10 a schematic flowchart for explaining a method of manufacturing a microelectromechanical sensor device according to yet another embodiment of the present invention.

In all figures, the same or functionally identical elements and devices - unless otherwise stated - provided with the same reference numerals. The numbering of method steps is for the sake of clarity and, in particular, should not, unless otherwise indicated, imply a particular chronological order. In particular, several method steps can be carried out simultaneously.

Description of the embodiments

1 shows a schematic cross-sectional view through a microelectromechanical sensor device 110 according to an embodiment of the present invention.

1 shows the sensor device 110 in a cross section in an xy plane, wherein a z-axis, which together with the x-axis and the y-axis forms an orthogonal tripod, emerges from the plane of the paper.

The sensor device 110 comprises at least one piezoelectric sensor structure 114 which is formed of a piezoelectric material, for example of PZT or of aluminum nitride. The piezoelectric sensor structure 114 is from first sections 111 , second sections 112 and third sections 113, which are thus each formed from the piezoelectric material.

In the sensor device 110 closes, in this order, to each of the first sections 111 the sensor structure 114 first one of the third sections 113 on, in turn, one of the second sections 112 , in turn, another of the third sections 113 , and in turn another of the first sections 111 and so on down to the ends of the sensor structure 114 ,

The first sections 111 the sensor structure 114 are all, in a rest position of the sensor structure 114 , arranged within a first virtual level or layer E1. The second sections 112 the sensor structure 114 are all, in the rest position of the sensor structure 114 , arranged within a second virtual level or layer E2.

The first virtual plane or layer E1 and the second virtual plane or layer E2 are different from each other and, in the rest position of the sensor structure 114 , arranged at a constant distance d1 from each other parallel to each other. The layer or virtual plane between the first virtual plane or layer E1 and the second virtual plane or layer E2 may also be referred to as intermediate layer or intermediate layer Z. A layer thickness of the intermediate plane or intermediate layer Z is thus equal to the distance d1.

The third sections 113 the sensor structure 114 all extend between the first virtual plane or layer E1 and the second virtual plane or layer E2, ie within the intermediate layer Z. The third sections 113 are preferably arranged perpendicular to the first and the second virtual plane or layer E1, E2, and in each case connect one of the first sections 111 to a respective one of the second sections 112 , which are thus in the range of the third sections 113 overlap.

The sensor structure 114 thus has a cross-section in the form of a periodic rectangular function, wherein the x-direction acts as abscissa and the y-direction as ordinate. In the positive and / or negative z-direction, the first, second and third sections extend 111 . 112 . 113 each further ahead and behind the paper level. The sensor structure 114 thus has a grooved or grooved three-dimensional structure which is comparable to a corrugated sheet, wherein the grooves or grooves extend with their longitudinal direction in the z-direction. The first and the second virtual plane or layer E1, E2 are arranged parallel to the xz plane, ie to the plane which is spanned by the x and z coordinate axes.

In the sensor structure 114 are all first sections 111 formed equal to each other, all second sections 112 formed equal to each other and all third sections 113 formed equal to each other, but this does not necessarily have to be so. Furthermore, in the sensor structure 114 the first and second sections 111 . 112 formed with the same dimensions, but this is not mandatory. Accordingly, in the sensor structure 114 a width B1 in the x-direction of each individual first section 111 equal to a width B2 in the x-direction of each individual second section 112 , The sensor structure 114 thus has a cross section in the form of a symmetric periodic rectangular function.

On a first side H1, eg in the negative y-direction, of the sensor structure 114 is at each of the first sections 111 a first electrode 121 attached as well as at each of the second sections 112 in each case a second electrode 122 appropriate. On a second side H2, eg in the positive y-direction, of the sensor structure 114 is at each of the first sections 111 a second electrode 122 is attached as well as at each of the second sections 112 in each case a first electrode 121 appropriate.

In an evaluation of the at the sensor structure 114 adjacent piezoelectric voltages can each voltages between the first electrodes 121 as the first pole on the one hand and the second electrodes on the other 122 On the other hand, the second pole is recorded and evaluated. The sensor device 110 with the sensor structure 114 is at the in 1 shown alignment, in particular for detecting bending of the sensor structure 114 usable around a bending axis, which is arranged parallel to the x-direction.

Except the sensor structure 114 can the sensor device 110 optionally comprise a frame device, on which the sensor structure 114 at one end of the sensor structure 114 or suspended from two or more ends of the sensor structure 114. Possible embodiments of a frame device are, for example, in the following 7d ) and 9d) are shown schematically. The sensor device 110 may alternatively be adapted to be connected at one or more ends to a frame means, ie to be suspended. For contacting the first and the second electrodes, vias may pass through the sensor structure 114 be formed, in particular the suspension of the sensor structure 114 adjacent to the frame device.

The sensor device 110 can also, or alternatively, have an evaluation, which electrically with the first electrode 121 and the second electrodes 122 is connected and which is adapted to a sensor signal based on a voltage, or voltages, between the first electrodes 121 and the second electrodes 122 to generate and output. The sensor device 110 may also be designed to be connected to an external evaluation device.

2 shows a schematic cross-sectional view through a microelectromechanical sensor device 210 with a sensor structure 214 according to another embodiment of the present invention. The sensor device 210 is a variant of the sensor device 110 and according to all with respect to the sensor device 110 customizable variants and modifications and vice versa.

The sensor structure 214 the sensor device 210 differs from the sensor structure 114 the sensor device 110 in that the sensor structure 214 has no third sections. In other words, the first portions 211 of the sensor structure 214 which otherwise may be formed as the first sections 111 the sensor structure 114 the sensor device 110 , directly with the second sections 212 the sensor structure 214 which may otherwise be formed as well as the second portions 112 of the sensor structure 114 the sensor device 110 , The first virtual plane or layer E1 is adjacent to the sensor device 210 directly to the second virtual layer or layer E2.

First and second electrodes (in 2 not shown) may also be on the first and second sections 211 . 212 be arranged and mounted, and evaluated, as with respect to the first and second electrodes 121 , 122 and the first and second sections 111 . 112 the sensor structure 114 the sensor device 110 described in the foregoing. Alternatively, the first and second electrodes may only be at the first portions 211 or only at the second sections 212 be arranged and mounted.

3 shows a schematic cross-sectional view through a microelectromechanical sensor device 310 with a sensor structure 314 according to yet another embodiment of the present invention.

The sensor device 310 is a variant of the sensor device 110 and according to all with respect to the sensor device 110 customizable variants and modifications and vice versa. The sensor device 310 differs from the sensor device 110 in particular, or exclusively, in that a width B2 'in the x-direction of the second sections 312 of the sensor structure 314 the sensor device 310 extending from a width B1 'in the x-direction of the first sections 311 the sensor structure 314 the sensor device 310 different, and that first electrodes 321 and second electrodes 322 only at the first sections 311 are arranged, but not at the second sections 312 ,

In particular, the width B2 'is each of the second sections 312 less than the width B1 'of each of the first sections 311 educated. The sensor structure 314 thus has a cross-section in the form of an asymmetric periodic rectangular function, wherein the x-direction as abscissa and the y-direction acts as ordinate.

As for the third sections 113 the sensor structure 114 in the preceding described, also extends to the sensor structure 314 between each a first section 311 in the first virtual layer or layer E1 and in each case a second section 312 in the second virtual plane or layer E2 of the sensor structure 314 exactly a third section 313 within the intermediate level or intermediate layer Z, ie between the first virtual level or layer E1 and the second virtual level or layer E2. Alternatively, the sensor structure 314 , as regards 2 described, without third sections 313 be formed, or the sensor structure 214 can second sections 212 with a smaller width than the first sections 211 as described with respect to the sensor structure 314.

4 shows a schematic cross-sectional view through a microelectromechanical sensor device 410 with a sensor structure 414 according to yet another embodiment of the present invention.

The sensor device 410 is a variant of the sensor device 310 and according to all with respect to the sensor device 310 customizable variants and modifications and vice versa. The sensor device 410 differs from the sensor device 310 in particular, or exclusively, in that between every two first sections 411 the sensor structure 414 within the first virtual level or layer E1 only exactly one second section 412 is formed, as in the sensor structure 314 the sensor device 310 , a sequence of two third sections 313 and a second section 312 ,

The second sections 412 the sensor structure 414 are formed as perpendicular to the first virtual plane or layer E1 tower structures passing through a second virtual plane or layer E2, which is from the first virtual plane or layer E1 by an intermediate layer Z, that is, by a non-disappearing distance d4, spaced. A width B2 "of the second sections 412 is less than a width B1 "of the first sections 411 , in particular less than half the width B1 "of the first sections 411 , preferably less than a quarter of the width B1 "of the first sections 411 ,

5 shows a schematic cross-sectional view through a microelectromechanical sensor device 610 according to yet another embodiment of the present invention. The sensor device 610 is a variant of the sensor device 110 and according to all with respect to the sensor device 110 customizable variants and modifications and vice versa.

The first, second and third sections 111 . 112 . 113 a sensor structure 614 of the sensor device 610 are designed as well as with respect to the sensor structure 114 the sensor device 110 described. The sensor device 610 differs from the sensor device 110 in that at the sensor structure 614 the first and second electrodes 121 . 122 , or a part of the first and second electrodes 121 . 122 , in pairs via electrical connections 623 connected in series, ie in series. The between each one first electrode 121 and a second electrode 122 adjacent (by deformation of the sensor structure 614 generated) voltages thus add up.

In this way, the voltages connected in series between the first and second electrodes 121 . 122 all advantageously on the first side H1 or on the second side H2 of the sensor structure 614 be tapped. Thus, elaborate plated-through holes through the sensor structure 614 be avoided.

Exemplary is in 5 shown that between the first electrode designated F1 121 and the second electrode designated F2 122 the serially connected voltages of four pairs of first and second electrodes 121, 122 can be tapped together, from the second side H2. All first and second electrodes are advantageous 121 . 122 connected in pairs in series.

6 shows a schematic flowchart for explaining a method for producing a microelectromechanical sensor device according to the invention according to yet another embodiment of the present invention. The method according to 6 is in particular for manufacturing one of the microelectromechanical sensor devices 110 ; 120 ; 310; 410 and is all according to the microelectromechanical sensor devices 110 ; 120 ; 310 ; 410 described modifications and developments adaptable and vice versa. The method according to 6 will be described below also by means of 7 be explained.

7 shows schematic cross-sectional views of an under construction according to the invention microelectromechanical sensor device according to the method according to 6 ,

In a step S01, at least one depression is made 502 in a surface 501 of a substrate 500 trained as in 7a ). Forming S01 of the at least one recess 502 can be done for example by one or more trench processes. In particular, an anisotropic etching process may be used For example, reactive deep ion etching (DRIE) or etching with potassium hydroxide, KOH.

As in 7a ), can have different width recesses 502 in the substrate 500 for example, to make first or second sections of different widths, as in the foregoing with respect to 1 to 4 was explained. Over a depth of the wells 502 For example, a later distance is adjustable between the first and second virtual planes or layers of the later completed microelectromechanical sensor device.

In a step S02 becomes a sacrificial layer 506 such on the substrate 500 , especially the surface 501 of the substrate 500 , that deposited the sacrificial layer 506 also the surfaces of the substrate 500 in the at least one recess 502 covered, as in 7b ) shown schematically. The sacrificial layer 506 may for example consist of silicon dioxide, SiO ₂ . Preferably, the sacrificial layer becomes 506 deposited in an isotropic process, for example by chemical vapor deposition (CVD) or a spin-on glass (SOG) process.

In a step S03, a piezoelectric layer is formed 514 applied to the sacrificial layer 506 such that the piezoelectric layer 514 at least in the - from the sacrificial layer 506 covered - at least one recess 502 is arranged as in 7c ) shown schematically. The application S03 of the piezoelectric layer 514 can be done in particular by an isotropic deposition. In this step, the electrodes can also be formed.

In a step S04, a partial removal of the substrate takes place 500 and the sacrificial layer 506 for partially exposing the piezoelectric layer 506 , ie for releasing the piezoelectric layer 514 such that the piezoelectric layer 514 as a sensor structure is suspended on the remaining substrate 500, which functions as a frame means. This can be a remainder of the sacrificial layer 506 maintained between the sensor structure and the frame device.

As in 7d ) can also be seen, forming on the sacrificial layer 506 away from the depressions 502 deposited regions of the piezoelectric layer 514 first sections 511 within a first virtual level or layer, as in the preceding with respect to the first sections 111 ; 211, 311; 411 described.

The on the sacrificial layer 506 in the area of the depressions 502 deposited regions of the piezoelectric layer 514 on the other hand, second portions 512-1, 512-2 arranged within or passing through a second virtual plane or layer form, as in the foregoing, with respect to the second portions 112 ; 212 ; 312 ; 412 described. Wells with small width, as in 7a ) to c) shown on the left, are suitable for this, second sections 512 - 1 which are formed as in the foregoing with respect to the second portions 412 the sensor structure 414 the sensor device 410 described. Recesses of greater width, as in 7a ) to c) each shown on the right are suitable for second sections 512 - 2 which are formed as in the foregoing with respect to the second portions 112 ; 212 ; 312 the sensor structures 114 ; 214 ; 314 the sensor devices 110 ; 210 ; 310 described.

The partial removal of the substrate can be done, for example, by trench processes. The partial removal of the sacrificial layer 506 can be done for example by appropriate etching processes. The sensor structure 514 can at the frame device, for example, behind and / or in front of the paper plane of 7 be hung up.

8th shows a schematic flowchart for explaining a method for producing a microelectromechanical sensor device according to the invention according to yet another embodiment of the present invention. The method according to 8th is in particular for manufacturing one of the microelectromechanical sensor devices 110 ; 120 ; 310; 410 and is all according to the microelectromechanical sensor devices 110 ; 120 ; 310 ; 410 described modifications and developments adaptable and vice versa. The method according to 8th will be described below also by means of 9 be explained.

9 shows schematic cross-sectional views of an under construction according to the invention microelectromechanical sensor device according to the method according to 8th ,

In a step S01 ', at least one increase 504 on a surface 501 of a substrate 500 trained as in 9a ). The formation S01 'of the at least one increase 504 can be done for example by depositing a first sacrificial layer and structuring the deposited first sacrificial layer. As a material for the first sacrificial layer, in particular oxides and / or nitrides are suitable, for example silicon dioxide. Also, a spin on glass method or polymer materials may be used.

As in 9a ), may have different width increases 504 on the substrate 500 for example, to make first or second sections of different widths, as in the foregoing with respect to 1 to 4 was explained. About a height of the raises 504 , ie in particular over a layer thickness of the deposited first sacrificial layer, a later distance between the first and the second virtual plane or layer of the later finished microelectromechanical sensor device is adjustable.

In a step S02 ', a second sacrificial layer is formed 506 deposited on the substrate 500 such that the second sacrificial layer 506 also the at least one increase 504 covered, as in 9b ) shown schematically. The second sacrificial layer 506 may for example consist of silicon dioxide, SiO ₂ . Preferably, the second sacrificial layer becomes 506 deposited in an isotropic process, for example by chemical vapor deposition (CVD) or spin-on glass (SOG). The first and second sacrificial layers are preferably formed of the same material.

In a step S03 ', a piezoelectric layer is formed 514 on the second sacrificial layer 506 applied such that the piezoelectric layer 514 at least on the - of the second sacrificial layer 506 covered - at least one increase 504 is arranged as in 9c ) shown schematically. The application S03 'of the piezoelectric layer 514 can be done in particular by an isotropic deposition. In this step, the electrodes can also be formed.

In a step S04 ', a partial removal of the substrate takes place 500 , the first sacrificial layer and the second sacrificial layer 506 for partially exposing the piezoelectric layer 514 , ie for releasing the piezoelectric layer 514 such that the piezoelectric layer 514 as a sensor structure on the remaining substrate 500 , which acts as a framework, is suspended. This can be a remainder of the sacrificial layer 506 maintained between the sensor structure and the frame device.

As in 9d 5) also form on the second sacrificial layer 506 away from the elevations 504 deposited regions of the piezoelectric layer 514 first sections 511 within a first virtual level or layer, as in the preceding with respect to the first sections 111 ; 211 . 311 ; 411 described.

The on the sacrificial layer 506 in the area of elevations 504 deposited regions of the piezoelectric layer 514 on the other hand, second portions 512-3, 512-4 arranged within or passing through a second virtual plane or layer form, as in the foregoing, with respect to the second portions 112 ; 212 ; 312 ; 412 described. The partial removal of the substrate can be done, for example, by trench processes. The partial removal of the first and / or the second sacrificial layer 506 can be done for example by appropriate etching processes. The sensor structure 514 can at the frame device, for example, behind and / or in front of the paper plane of 9 be hung up.

It is understood that the methods according to 6 and 8th can also be combined with each other, ie it can on one and the same substrate 500 both at least one depression 502 as well as at least one increase 504 be formed. In this case, for example, portions may be arranged in three spaced-apart, parallel virtual planes or layers, corresponding to an arrangement of piezoelectric material on the sacrificial layer in i) the depressions 502 , ii) on the surface 501 of the substrate 500 and iii) on the ridges 504 , Alternatively, first and second sections can only be on the elevations 504 and in the wells 502 be formed so that a particularly large distance between the first and the second virtual level or layer can be achieved.

10 shows a schematic flowchart for explaining a method for producing a microelectromechanical sensor device according to the invention according to yet another embodiment of the present invention. The method according to 10 is in particular for manufacturing one of the microelectromechanical sensor devices 110 ; 120 ; 310; 410 and is all according to the microelectromechanical sensor devices 110 ; 120 ; 310 ; 410 described modifications and developments adaptable and vice versa.

In a step S11, a sacrificial layer is deposited on a substrate. In a step S12, a piezoelectric layer is deposited on the sacrificial layer.

In a step S13, the piezoelectric layer is patterned. The piezoelectric layer is patterned such that a number of first portions of the piezoelectric layer are disposed within a first virtual plane or layer, and further such that a number of second portions of the piezoelectric layer are disposed within a second virtual plane or layer or a second virtual one Traversing level or layer, the first virtual level or Layer and the second virtual layer or layer are different from each other and arranged parallel to each other.

For example, the piezoelectric layer may be formed by spatially periodically removing spaced strips of piezoelectric material, such as the sensor structure 414 the sensor device 410 ,

In a step S14, partial removal of the substrate and the sacrificial layer to partially freeze the patterned piezoelectric layer, i. for releasing the piezoelectric layer such that the piezoelectric layer is suspended as a sensor structure on the remaining substrate which functions as a frame means.

Although the present invention has been described above with reference to preferred embodiments, it is not limited thereto, but modifiable in a variety of ways. In particular, the invention can be varied or modified in many ways without deviating from the gist of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2014/0339657 A1 [0004]

Claims (11)

Micromechanical sensor device (110; 210; 310; 410; 610), comprising: a piezoelectric sensor structure (114; 214; 314; 414; 614); wherein the piezoelectric sensor structure (114; 214; 314; 414; 614) comprises a number of first portions (111; 211; 311; 411; 511) disposed within a first virtual plane or layer (E1) and wherein the piezoelectric sensor structure (114; 214; 314; 414; 614) comprises a number of second portions (112; 212; 312; 412; 512-i) disposed within a second virtual plane or layer (E2) traverse the second virtual plane or layer (E2); wherein the first virtual plane or layer (E1) and the second virtual plane or layer (E2) are different from each other and arranged parallel to each other. Sensor device (110; 210; 610) Claim 1 wherein the first sections (111; 211) and the second sections (112; 212) are aligned in a direction (x) parallel to the first and / or the second virtual plane or layer (E1, E2) of equal width (B1, B1). B2) are formed. Sensor device according to (310; 410) Claim 1 wherein the first sections (311; 411) and the second sections (312; 412) are arranged in a direction (x) parallel to the first and / or the second virtual plane or layer (E1, E2) with different widths (B1 ', B2 ', B1 ", B2") are formed. Sensor device (110, 210, 610) according to one of Claims 1 to 3 wherein adjacent first portions (111; 211) and second portions (112; 212) of the piezoelectric sensor structure (114; 214) each partially overlap each other. Sensor device (110; 210; 310; 410; 610) according to one of Claims 1 to 4 , with a frame device; wherein the piezoelectric sensor structure (114; 214; 314; 414; 614) is suspended from the frame means at one end of the piezoelectric sensor structure (114; 214; 314; 414; 614) or at two ends of the piezoelectric sensor structure (114; 214; 414, 614) is suspended from the frame means. Sensor device (110, 210, 610) according to one of Claims 1 to 5 , wherein a first electrode (121) and a second electrode (122) are respectively arranged on the first sections (111; 211) and on the second sections (112; 212). Sensor device (110, 210) according to Claim 6 wherein on a first side (H1) of the sensor structure (114; 214) the first electrodes (121) are arranged on the first sections (111; 211) and the second electrodes (122) on the second sections (112; 212); and wherein on a second side (H2) of the sensor structure (114; 214) the second electrodes (122) are arranged on the first sections (111; 211) and the first electrodes (122) are arranged on the second sections (112; 212). Sensor device (310; 410) according to one of Claims 1 to 5 wherein first electrodes (321; 421) and second electrodes (322; 422) are disposed only at the first portions (311; 411). Sensor device (110; 210; 310; 410) according to one of Claims 6 to 8th sensor comprising an evaluation device electrically connected to the first electrodes (121; 221; 321; 421) and the second electrodes (122; 222; 322; 422) and adapted to generate a sensor signal based on at least one voltage between them first electrodes (121; 221; 321; 421) and the second electrodes (122; 222; 322; 422) to generate and output. A method of manufacturing a micromechanical sensor device (110; 210; 310; 410), comprising the steps of: Forming (S01; S01 ') at least one depression (502) and / or at least one elevation (504) in or on a surface (501) of a substrate (500); Depositing (S02; S02 ') a sacrificial layer (506) on the substrate (500) and the at least one depression (502) and / or at least one elevation (504); Forming (S03; S03 ') a piezoelectric layer (514) on the sacrificial layer (506) at least in the region of the at least one depression (502) and / or at least one elevation (504); and Partially removing (S04; S04 ') the substrate (500) and the sacrificial layer (506) to partially expose the piezoelectric layer (514). A method of manufacturing a micromechanical sensor device (110; 210; 310; 410), comprising the steps of: depositing (S11) a sacrificial layer on a substrate; Forming (S12) a piezoelectric layer on the sacrificial layer; Patterning (S13) the piezoelectric layer to produce a number of first portions of the piezoelectric layer disposed within a first virtual plane or layer (E1) and a number of second portions of the piezoelectric layer that are within a second virtual plane or layer (E2) are arranged or traverse a second virtual plane or layer (E2); wherein the first virtual plane or layer (E1) and the second virtual plane or layer (E2) are different from each other and arranged in parallel with each other; and partially removing (S14) the substrate and the sacrificial layer to partially expose the piezoelectric layer.

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