MEMS sensor for measuring a surroundings variable of the sensor surroundings

Abstract

The invention relates to a MEMS sensor for measuring a surroundings variable of the sensor surroundings, comprising: a substrate and a layer system which has a plurality of electrically conductive and / or non-electrically conductive layers, the layer system being subdivided at least into an anchoring region, a sensing region, a frame structure surrounding the sensing region, and at least one spring structure designed to be movable between the anchoring region and the frame structure, wherein the anchoring region is at least partly situated on the substrate, the frame structure is elastically connected to the anchoring region via the at least one spring structure, and one or more electrically conductive and / or non-electrically conductive layers of the sensing region are connected to the frame structure, the sensing region comprising: a first membrane which can be deflected in a vertical direction on the basis of the surroundings variable, a second membrane which is situated at a distance from the first membrane in the vertical direction, is mechanically connected to the first membrane, and is deflected in the vertical direction on the basis of the surroundings variable such that a deflection of the first membrane is coupled to a deflection of the second membrane, and a central electrode structure which is situated between the first and the second membrane at a distance therefrom.

Description

[0001] R. 414485

[0002] Description

[0003] title

[0004] The invention relates to a MEMS sensor for measuring an environmental parameter of a sensor environment.

[0005] State of the art

[0006] The patent application DE 10 2017204 023 A1 discloses a MEMS device and a MEMS vacuum microphone.

[0007] The patent application DE 10 2020 134 171 A1 discloses a sound transducer.

[0008] German patent application DE 10 2021 133 848 A1 discloses a MEMS device with electrodes and a dielectric.

[0009] The patent application EP 3 754 325 A1 discloses a photoacoustic gas sensor and a pressure sensor.

[0010] The patent application DE 10 2015 103 236 A1 discloses a MEMS sensor structure for sensing pressure waves and changes in ambient pressure.

[0011] The patent application DE 10 2017212 613 A1 discloses a MEMS component and a manufacturing process for a MEMS component.

[0012] The patent application CN 107 285273 A discloses a MEMS device.

[0013] Disclosure of invention R. 414485

[0014] - 2 -

[0015] The object underlying the invention is to provide a MEMS sensor for measuring an environmental parameter of a sensor environment.

[0016] This problem is solved by means of the subject matter according to the independent claim. Advantageous embodiments of the invention are the subject of dependent claims.

[0017] According to one aspect, a MEMS sensor for measuring an environmental parameter of a sensor environment is provided, comprising: a substrate, a layer system having several layers, in particular electrically conductive and / or electrically non-conductive layers, wherein the layer system is divided into at least an anchoring region, a sensing region, a frame structure surrounding the sensing region, and at least one spring structure movably configured between the anchoring region and the frame structure, wherein the anchoring region is substantially at least partially arranged on the substrate, wherein the frame structure is elastically connected to the anchoring region via the at least one spring structure, and wherein one or more layers of the sensing region, in particular electrically conductive and / or electrically non-conductive layers, are connected to the frame structure.The sensing area comprises: a first membrane that can be deflected vertically depending on the ambient conditions; a second membrane arranged vertically spaced from the first membrane, mechanically connected to the first membrane and deflected vertically depending on the ambient conditions, such that a deflection of the first membrane is coupled to a deflection of the second membrane; and a central electrode structure arranged between the first and second membranes at a distance from them. R. 414485

[0018] - 3 -

[0019] The abbreviation “MEMS” stands for “Micro-Electro-Mechanical System”.

[0020] The fact that the anchoring area is at least partially located on the substrate means, for example, that the anchoring area is essentially located on the substrate. The anchoring area can, for example, extend into the area free of substrate and thus does not end, for example, directly at a substrate edge.

[0021] By elastically connecting the sensing area to the frame structure via at least one spring structure, which in turn is connected to the substrate via an anchoring area, the particular technical advantage is achieved that an influence on the sensor signal by stress coupling due to an AVT (assembly and connection technology) of the MEMS sensor on, for example, the substrate, which can be an ASIC substrate or a printed circuit board substrate, can be reduced or completely avoided.

[0022] According to the prior art described above, the sensing area of ​​a microphone sensor, consisting of movable membrane structures that are mechanically and / or electrically connected to each other in certain areas via support structures, as well as a fixed, penetrated central electrode located between the membrane structures and freely movable by the support structures, is typically attached directly to an anchoring area surrounding the sensing area. This anchoring area also circumferentially defines a cavity formed between the membrane structures.

[0023] If warping and / or torsion of the sensor chip occurs during the assembly of the known microphone sensor, this is transmitted via the anchoring area to the sensing area of ​​the sensor and thus influences the formation of the sensor signal characteristic curve. R. 414485

[0024] - 4 -

[0025] Due to the at least one spring structure provided according to the concept described here, which elastically connects the sensing area to the surrounding frame structure, the technical advantage is achieved, for example, that the sensing area for detecting the ambient quantity, e.g. sound pressures, is effectively decoupled from the surrounding layer system and / or the surrounding substrate in terms of stress, and influences on the sensor signal caused by the AVT (assembly and connection technology) of the MEMS sensor can be reduced / avoided.

[0026] A substrate, as described, is for example a silicon substrate. A substrate, as described, is for example an ASIC substrate. A substrate, as described, is for example a printed circuit board substrate. A substrate, as described, is for example a wafer, in particular a silicon wafer.

[0027] ASIC stands for "Application Specific Integrated Circuit", which can be translated into German as "anwendungsspezifische integrierte Schaltung".

[0028] The phrase “at least one” means “one or more”.

[0029] The first membrane and the second membrane can, for example, perform a relative movement with respect to the central electrode structure.

[0030] In one embodiment of the MEMS sensor, it is provided that a layer structure of the at least one spring structure essentially corresponds to the layer structure of the adjacent frame structure and the adjacent anchoring area.

[0031] This results, for example, in the technical advantage that the production of the MEMS sensor can be efficiently simplified.

[0032] In one embodiment of the MEMS sensor, it is provided that an electrical supply line for the center electrode structure is provided in a, in particular central, area of ​​the at least one spring structure, wherein R. 414485

[0033] - 5 - electrical supply line is electrically insulated from the layer(s) flanking and / or limiting at least one spring structure.

[0034] This results, for example, in the technical advantage that electrical short circuits can be efficiently avoided.

[0035] In one embodiment of the MEMS sensor, the layer system comprises at least one support structure arranged between the first membrane and the second membrane, connecting the first membrane and the second membrane.

[0036] This results, for example, in the technical advantage that the two membranes can be efficiently connected or coupled to each other. A support structure, as described, mechanically connects the first and second membranes, so that a deflection of the first membrane is coupled to a deflection of the second membrane.

[0037] For example, the support structure can be electrically conductive or electrically insulating. The support structure may, for example, have an electrically insulating area, such as an insulating layer, to connect or couple the first and second membranes in a non-conductive manner.

[0038] In one embodiment of the MEMS sensor, it is provided that one or more flanking and / or limiting layers of the at least one spring structure consist essentially of the same material composite or comprise such a composite as the material composite of the at least one support structure.

[0039] This results, for example, in the technical advantage that the MEMS sensor can be manufactured efficiently and in a simplified manner.

[0040] In one embodiment of the MEMS sensor, it is provided that one or more flanking and / or limiting layers of the at least one R. 414485

[0041] - 6 -

[0042] The spring structure is electrically isolated from each other to avoid an electrical short circuit between electrically conductive areas / layers / structures of the layer system forming the MEMS sensor.

[0043] This results, for example, in the technical advantage that an electrical short circuit, for example between the first membrane and the second membrane and between the first and / or second membrane and a center electrode structure, can be efficiently avoided.

[0044] In one embodiment of the MEMS sensor, it is provided that a free space between the anchoring area and / or the frame structure and / or the side wall or side walls facing the at least one spring structure are formed from the same layers and / or layer materials or comprise such layers and / or layer materials and / or have essentially the same material composition or consist of such a material as the at least one spring structure.

[0045] This results, for example, in the technical advantage that the MEMS sensor can be manufactured efficiently and in a simplified manner.

[0046] In one embodiment of the MEMS sensor, the layer system comprises an electrically insulating layer in a region of one or more side walls that separate a cavern area formed between the first membrane and the second membrane from the frame structure surrounding the cavern area, so that the center electrode structure is electrically insulated from the first membrane and the second membrane in the frame structure and extends from there, via the at least one spring structure, electrically insulated from the layers flanking and / or limiting the spring structure, into the anchoring area.

[0047] This results, for example, in the technical advantage that electrical short circuits can be efficiently avoided. R. 414485

[0048] - 7 - In one embodiment of the MEMS sensor, it is provided that the at least one spring structure is designed to be stiffer at least in a vertical direction or in a direction perpendicular to the main extension plane of the sensing area than a suspension of the sensing area on the frame structure.

[0049] This results, for example, in the technical advantage that the ambient quantity can be measured efficiently. According to this embodiment, the at least one spring structure, which provides stress decoupling, is preferably designed to be stiffer in the direction of an incoming sound wave than the suspension of the sensing area, in particular the two membranes, on the frame structure. When a sound wave arrives, the membrane, or the two membranes, within the sensing area of ​​the MEMS sensor essentially move relative to a central electrode structure.

[0050] In one embodiment of the MEMS sensor, it is provided that at least one of the spring structure and the frame structure each comprise a thickening formed by a substrate part formerly connected to the substrate.

[0051] This results, for example, in the technical advantage that the elasticity or stiffness of the spring structure or the frame structure can be efficiently adjusted.

[0052] In one embodiment of the MEMS sensor, the center electrode structure comprises a first center electrode and a second center electrode vertically opposite the first center electrode, wherein the first center electrode and the second center electrode are electrically isolated from each other.

[0053] This results, for example, in the technical advantage that two capacitor structures can be efficiently formed with the two membranes: a first capacitor structure is formed, for example, by the first center electrode and by the first membrane. A second capacitor structure R. 414485

[0054] - 8 - is formed, for example, by the second center electrode and the second membrane.

[0055] The fact that the two center electrodes are electrically isolated from each other results, for example, in the technical advantage that the two capacitor structures can be efficiently formed as a differential capacitor structure.

[0056] In one embodiment of the MEMS sensor, the at least one support structure is electrically conductive, so that the first membrane and the second membrane are electrically connected to each other via the at least one support structure.

[0057] This results, for example, in the technical advantage that the differential capacitor structure described above can be manufactured efficiently.

[0058] In one embodiment of the MEMS sensor, the sensing area is further comprised as layers: a first electrode, which is arranged between the first membrane and the center electrode structure at a vertical distance from these, such that a first capacitor structure is formed by the first electrode and the center electrode structure, and a second electrode, which is arranged between the second membrane and the center electrode structure at a vertical distance from these, such that a second capacitor structure is formed by the second electrode and the center electrode structure.

[0059] This results, for example, in the technical advantage that a differential capacitor structure can be formed efficiently.

[0060] In one embodiment of the MEMS sensor, the sensing area is connected to the frame structure, in particular only, via the first electrode and / or the second electrode, or via the layer(s) forming the first electrode and / or the second electrode. R. 414485

[0061] - 9 -

[0062] This results, for example, in the technical advantage of an efficient and flexible connection of the sensing area.

[0063] In one embodiment of the MEMS sensor, it is provided that one or more electrical leads to the first electrode and / or to the second electrode in the sensing area are electrically insulated from each other, electrically insulated from structure-bounding side walls, electrically insulated from the center electrode structure and its electrical lead(s), and electrically insulated from the first membrane and electrically insulated from the second membrane by running through the spring structure and through the frame structure.

[0064] This results, for example, in the technical advantage that electrical short circuits within the layer structure can be efficiently avoided.

[0065] In one embodiment of the MEMS sensor, it is provided that the sensing area is connected to the frame structure, in particular only via the first membrane and / or the layer forming the second membrane.

[0066] This results, for example, in the technical advantage that the sensing area can be connected more elastically to the surrounding frame structure.

[0067] In one embodiment of the MEMS sensor, it is provided that the first and / or the second electrode is elastically connected to the frame structure by means of at least one further spring structure.

[0068] The at least one additional spring structure advantageously serves as an elastically designed electrical contact / connection of the electrodes. If the two electrodes are made more massive, for example, to be used as counter electrodes for the adjacent membrane during an additional ambient pressure measurement, it is helpful to have an elastic electrical connection of the electrodes to prevent movement of the membrane. R. 414485

[0069] - 10 -

[0070] / to influence or reduce the flexibility of the electrode assembly as little as possible.

[0071] For example, it is provided that the electrodes in the sensing area are electrically contacted by means of at least one further elastic / flexible spring structure penetrating at least one side wall of the cavern area, electrically insulated from the surrounding layer system.

[0072] In one embodiment of the MEMS sensor, for example, exactly one center electrode is provided. This means that, for example, the center electrode structure comprises only a single center electrode.

[0073] In one embodiment of the MEMS sensor, for example, exactly two center electrodes, the first and the second center electrode, are provided. This means, for example, that the center electrode structure comprises exactly two center electrodes, the first center electrode and the second center electrode.

[0074] In one embodiment of the MEMS sensor, it is provided that it is a pressure sensor, a microphone, a combination of both, and / or is designed as a MEMS transducer.

[0075] This results, for example, in the technical advantage that particularly suitable MEMS sensors can be used.

[0076] A support structure as described above penetrates in particular the first electrode, and is freely movable through the center electrode structure, i.e., for example, the first center electrode and the second center electrode, and in particular the second electrode.

[0077] Electrode structure refers to the first electrode and the second electrode. The terms "center electrode structure" and "counter electrode structure" can be used synonymously. A membrane, as described, is a deformable membrane. The terms "membrane" and "membrane structure" R. 414485

[0078] - 11 - can be used synonymously. When the term "support structure" is used, the plural should always be implied, and vice versa. For example, several support structures are planned. Statements made in connection with one support structure apply analogously to multiple support structures, and vice versa.

[0079] When the term "spring structure" is used, the plural and vice versa should always be implied. For example, several (additional) spring structures are planned. Statements made in connection with one (additional) spring structure apply analogously to several (additional) spring structures and vice versa.

[0080] For the purposes of this description, a layer is, for example, an electrically conductive layer or an electrically non-conductive layer.

[0081] A layered system as described can, for example, have or comprise several electrically conductive and / or several electrically non-conductive layers.

[0082] A layer, as described, is therefore, for example, electrically conductive or electrically non-conductive.

[0083] In one embodiment of the MEMS sensor, it is provided that the two membranes each have a bead-shaped structure bridging a break in the layers forming the membranes.

[0084] This structure advantageously allows for an even softer / more flexible suspension / connection of the sensing area to the frame structure surrounding it. To better distinguish it from the electrode structure described below, this structure can be referred to as a first structure. This structure thus bridges a gap in the layers forming the membranes.

[0085] The two membranes thus each exhibit a break in the layers forming the membranes R. 414485

[0086] - 12 - bridging / covering rib-shaped or channel-shaped structure, which allows for an even softer / more flexible suspension / connection of the sensing area to the frame structure surrounding the sensing area.

[0087] The structure thus exhibits a corrugated or trough shape. In other words, each of the two membranes has a corrugated or trough shape: the structure. This structure is located, for example, within the sensing area, and specifically in the area, adjacent to, or near the frame structure, and is at least partially formed from layers of the layer system. The structure can be localized, for example, or it can be a self-contained structure that follows the contour of the sensing area.

[0088] In one embodiment of the MEMS sensor, it is provided that the two electrodes each have a bead-shaped structure bridging a break in the layers forming the electrodes.

[0089] This structure advantageously allows for an even softer / more flexible suspension / connection of the sensing area to the frame structure surrounding it. To better distinguish it from the membrane structure described above, this structure can be referred to as a second structure. This structure thus bridges a gap in the layers forming the electrodes.

[0090] For example, each of the two electrodes has a bead-shaped or channel-shaped structure bridging / covering a break in the electrode-forming layers, which allows for an even softer / more flexible suspension / connection of the sensing area to the frame structure surrounding the sensing area.

[0091] The structure therefore has a beaded or grooved shape. In other words, each of the two electrodes has a bead or groove: the structure. The structure is located, for example, within the R. 414485

[0092] - 13 -

[0093] The sensing area, for example, is located in or adjacent to the frame structure and is at least partially formed from layers of the layer system. The structure can be localized or, for example, a self-contained structure that follows the contour of the sensing area.

[0094] In one embodiment of the MEMS sensor, it is provided that the respective corrugated structure consists of or comprises a material of the membrane-forming layers and / or of a material of the electrode-forming layers and / or of a material of a layer forming a dielectric layer of the layer system and designed to be etch-resistant against a sacrificial etching medium.

[0095] The embodiments and examples described here can be combined in any way, even if this is not explicitly described.

[0096] The invention is explained in more detail below with reference to preferred embodiments. These include:

[0097] Fig. 1 shows a first MEMS sensor,

[0098] Fig. 2 shows a second MEMS sensor,

[0099] Fig. 3 shows a third MEMS sensor,

[0100] Fig. 4 shows a fourth MEMS sensor,

[0101] Fig. 5 shows a fifth MEMS sensor,

[0102] Fig. 6 shows a sixth MEMS sensor,

[0103] Fig. 7 shows a seventh MEMS sensor, R. 414485

[0104] - 14 -

[0105] Fig. 8 shows an eighth MEMS sensor,

[0106] Fig. 9 shows a ninth MEMS sensor,

[0107] Fig. 10 shows a tenth MEMS sensor,

[0108] Fig. 11 shows an eleventh MEMS sensor,

[0109] Fig. 12 shows a twelfth MEMS sensor and

[0110] Fig. 13 shows a thirteenth MEMS sensor.

[0111] The same reference symbols can be used for identical features in the following.

[0112] The views in Figs. 1 to 13 are cross-sectional views, where the corresponding MEMS sensor is shown only partially or only in part or in part.

[0113] Fig. 1 shows a first MEMS sensor 101 for measuring an environmental parameter of a sensor environment.

[0114] The first MEMS sensor 101 includes a substrate 103. The substrate 103 is, for example, a silicon substrate, such as a silicon wafer.

[0115] The first MEMS sensor 101 comprises a layer system 105, which has several layers, in particular electrically conductive and / or electrically non-conductive layers, several of which are designated by reference numeral 107. The layers of the layer system 105 are explained or defined in more detail below, at least in part.

[0116] The layer system 105 is subdivided into at least an anchoring area 109, a sensing area 111, a frame structure 113 surrounding the sensing area, and at least one spring structure 115 movably formed between the anchoring area 109 and the frame structure 113. R. 414485

[0117] - 15 -

[0118] The anchoring area 109 or the layers 107 of the anchoring area 109 are preferably or essentially, generally at least partially, arranged on the substrate 103.

[0119] The frame structure 113 is elastically connected to the anchoring area 109 via at least one spring structure 115.

[0120] One or more layers 107 of the sensing area 111 are connected to the frame structure 113 and / or are at least partially / are part of the frame structure 113.

[0121] The sensing area 111 comprises a first membrane 119, which is deflectable in a vertical direction, indicated by an arrow with reference numeral 117, depending on the ambient conditions. The sensing area 111 comprises a second membrane 121, which is arranged at a distance in the vertical direction 117 from the first membrane 119, is mechanically connected to the first membrane 119, and is deflectable in the vertical direction 117 depending on the ambient conditions. The sensing area 111 comprises a central electrode structure 123, which is arranged at a distance between the first and second membranes 119, 121 and with respect to which the first and second membranes 119, 121 can move relative.

[0122] In the embodiment shown in Fig. 1, the center electrode structure 123 comprises a single center electrode 125.

[0123] The two membranes 119, 121 are mechanically connected to each other via at least one support structure 127, such that a deflection of the first membrane 119 is coupled to a deflection of the second membrane 121. This coupling is symbolically indicated by a double arrow with the reference numeral 129.

[0124] Reference numeral 131 refers to dielectric layers or dielectric layer stacks of the layer system 105, which serve for electrical insulation at the corresponding locations. R. 414485

[0125] - 16 -

[0126] For example, at least one support structure 127 has a dielectric layer 131 to electrically isolate the first membrane 119 and the second membrane 121 from each other and to achieve / effect an electrically non-conductive coupling between the first and second membranes 119, 121. Accordingly, further electrically non-conductive layers or layer stacks 131 are provided, so that in total the two membranes 119, 121 are electrically isolated from each other.

[0127] Thus, a first capacitor structure is formed between the central electrode 125 and the first membrane 119. Thus, a second capacitor structure is formed between the central electrode 125 and the second membrane 121.

[0128] In the first MEMS sensor 101, it is intended that only the first membrane 119 and the second membrane 121 are used to connect the sensing area 111 to the frame structure 113.

[0129] In the first MEMS sensor 101, it is provided that the layers forming the first membrane 119, the second membrane 121, the center electrode 125 and the electrically non-conductive layer stack(s) are used to create a frame structure 113 completely surrounding the sensing area 111, to which the first and second membranes 119, 121 as well as the center electrode structure 125 are electrically insulated from each other.

[0130] Thus, Fig. 1 shows a MEMS sensor 101 in which a frame structure 113 is provided around the sensing area 111 of the MEMS sensor 101. This frame structure serves to support the membranes 119, 121 and to attach the center electrode structure 123. The frame structure 113 is formed from the layers and layer materials of the layer system 105 and is elastically connected via the at least one spring structure 115 to the anchoring area 109, which at least partially surrounds the frame structure 113 and is spatially separated from it. The at least one spring structure 115 is connected to the frame structure 113 at least at one point and to the R. 414485 at least at one point.

[0131] - 17 - surrounding anchoring area 109 and is otherwise freely movable between the frame area 113 and the anchoring area 109. This possibility can also be implemented in further embodiments or configurations as disclosed in the description.

[0132] Specifically, the upper surface of the spring structure 115, the frame structure 113 and the anchoring area 109, which faces away from a layer forming the central electrode structure 123, is preferably arranged in one plane.

[0133] The layer structure of the at least one spring structure 115 corresponds, for example, essentially to that of the adjacent frame structure 113 and the adjacent anchoring area 109. In a central area 135 of the at least one spring structure 115, an electrical supply line 145 for the central electrode 125 is provided, electrically insulated from the layers 131, 137, 139, 141, 143 flanking / bounding the spring structure 115. The corresponding electrical insulation is marked with reference numeral 147.

[0134] The layers 131, 137, 139, 141, 143 flanking or bounding the spring structure 115 consist, for example, essentially of the same material composite as the support structure 127 between the membranes 119, 121 within the sensing area 111 and thus, for example, of the material of the membrane 119, 121, for example, doped polysilicon, the material of the center electrode 125, for example, doped polysilicon, the material of the dielectric layer, for example, SiRiN (silicon rich silicon nitride) and / or SiCN (silicon carbonitride), and, for example, additionally of an electrically insulating material, the electrical insulation 147, such as SiO2 (silicon dioxide), with which an electrical short circuit between the layers 131, 137, 139, 141 flanking or bounding the spring structure 115 is prevented. , 143 can be avoided.

[0135] The space 149 between anchoring area 109 and / or a frame structure 113 and / or a spring structure 115 respectively facing R. 414485

[0136] - 18 - opposite side walls 151 of the anchoring area 109 and / or the frame structure 113 can, for example, consist of the same layers or layer materials as in the at least one spring structure 115 and can, for example, also have the same material composite.

[0137] In the area of ​​a further side wall 152, which separates a cavern area 153 between the membranes 119, 121 from the frame structure 113 surrounding the cavern area 153, a second electrically insulating and etch-resistant insulating layer 131 is provided, for example, in order to guide the central electrode 125 electrically insulated from the membrane 119, 121 into the frame structure 113 and from there via the spring structure 115 into the anchoring area 109 and into the layer system 105 surrounding the anchoring area 109, and to prevent an etching attack on sacrificial layer material in the frame structure 113, the spring structure 115 and the anchoring area 109 during the removal of sacrificial layer material from the cavern area 153. The sacrificial layer material can, for example, consist of SiO2 and preferably correspond to the material of the electrical insulation 147.

[0138] With the aid of such a spring structure 115, the sensing area 111 for detecting the ambient quantity, in particular for detecting sound pressures, can be effectively decoupled from the surrounding layer system 105 and / or the surrounding substrate 103 with respect to stress, and influences on the sensor signal caused by the AVT of the MEMS sensor 101 can be reduced or avoided. In the design of the at least one spring structure 115, it is provided, for example, that the at least one spring structure 115 for stress decoupling in the direction of an incoming sound wave is designed to be stiffer than the suspension of the membrane 119, 121 or the membrane assembly forming it on the frame structure 113.

[0139] Fig. 2 shows a second MEMS sensor 201 for measuring an environmental parameter of a sensor environment. R. 414485

[0140] - 19 -

[0141] In the second MEMS sensor 201, areas of the substrate 103 are provided for increasing the stiffness of the spring structure 115 and / or the frame structure 113 surrounding the sensing area 111. Thus, the spring structure 115 and the frame structure 113 each comprise a thickening 205 formed by a substrate part 203 formerly connected to the substrate 103. Optionally, at least in some areas of the thickening 205, an electrically non-conductive layer 107 can be provided / present between the substrate part 203 and the layer forming the second membrane 121.

[0142] Fig. 3 shows a third MEMS sensor 301 for measuring an environmental parameter of a sensor environment.

[0143] The center electrode structure 123 of the third MEMS sensor 301 comprises a first center electrode 303 and a second center electrode 305, which are electrically isolated from each other by a dielectric layer 307, provided at least in certain areas. The dielectric layer 307 can, for example, be a stress decoupling layer. The electrical separation of the two center electrodes 303 and 305 can thus be achieved by means of a dielectric layer 307, which is etch-resistant to the SiO2 sacrificial layer etching medium and is provided at least in certain areas. In this embodiment, side walls 151 of the corresponding structures 109, 115, 113, which flank the free space 149, i.e. a free area for stress decoupling of the sensing area 111, can consist entirely of polysilicon and electrically connect the membranes 119, 121 and the layers forming the membranes 119, 121 respectively.Despite the electrical separation of the center electrodes 303, 305 and the mechanically and electrically conductively connected membranes 119, 121, capacitor structures, the first capacitor structure and the second capacitor structure, can be generated, whose capacitances and / or changes in capacitance can be used to detect relative movement of the membrane assembly, i.e., the assembly of the first and second membranes 119, 121, with respect to the center electrodes 303, 305. R. 414485.

[0144] - 20 -

[0145] Fig. 4 shows a fourth MEMS sensor 401 for measuring an environmental parameter of a sensor environment.

[0146] In contrast to the first MEMS sensor in Fig. 1, where the opposing side walls 151 of the corresponding structures 109, 115, 113, which flank the exposed area 149 for stress decoupling of the sensing area 111 and / or side walls 152, which enclose the cavern area 153 and serve here as lateral etch stop structures, are at least partially made of, for example, a dielectric layer such as a SiRiN and / or a SiCN layer, the dielectric layers 131 comprise or consist of SiRiN and / or SiCN.

[0147] Fig. 5 shows a fifth MEMS sensor 501 for measuring an environmental parameter of a sensor environment.

[0148] The fifth MEMS sensor 501 is a variant of the second MEMS sensor 201 of Fig. 2, in which additional electrodes, a first electrode 503 and a second electrode 505, are provided, which are mechanically and electrically conductively connected via support structures 127 and support structure areas respectively to the respective corresponding / adjacent membranes 119, 121.

[0149] Thus, the fifth MEMS sensor 501 comprises a first electrode 503, which is arranged between the first membrane 119 and the center electrode structure 123 at a distance from these, so that a first capacitor structure is formed by the first electrode 503 and the center electrode structure 123, in this case the only center electrode 125.

[0150] Thus, the fifth MEMS sensor 501 comprises a second electrode 505, which is arranged between the second membrane 121 and the center electrode structure 123, in this case the single center electrode 125, at a distance from these, such that the second electrode 505 and the center electrode structure 123 form a second capacitor structure. R. 414485

[0151] - 21 -

[0152] The first electrode 503 is electrically connected to the first membrane 119 via the support structure 127. The second electrode 505 is electrically connected to the second membrane 121 via the support structure 127. The first and second electrodes 503, 505 are electrically non-conductively connected to each other via the support structure 127, which freely penetrates the central electrode 125. The support structure 127 comprises at least one dielectric layer 131 in the region between the first and second electrodes 503, 505, such that the two membranes 119, 121 and the two electrodes 503, 505 are electrically isolated from each other via the support structure 127. Furthermore, additional dielectric layers 131 are provided, as already explained in connection with Fig. 1, which connect / couple the two membranes 119, 121 and the two electrodes 503, 505 in an electrically non-conductive manner.

[0153] The layers for producing these electrodes 503, 505 can, for example, again consist of doped polysilicon and extend from the sensing area 111 at least partially or preferably completely over the frame structure 113 and the spring structure 115 to the anchoring area 109, and are used to increase the mechanical stability of the frame structure 113 and to increase the spring stiffness of the spring structure 115. Since the electrodes 503, 505 are electrically conductively connected to the corresponding membranes 119, 121, the layer structure around the central electrode structure 123 can be retained unchanged.Electrodes 503 and 505 can, for example, be used to reduce or eliminate additional influences on the sensor signal characteristic curve caused by ambient pressure and / or deflections / changes in deflection of the membranes 119 and 121 in the area between support structures 127 caused by changes in ambient pressure. Furthermore, the use of these electrodes 503 and 505 can linearize the determined sensor characteristic curve.

[0154] Fig. 6 shows a sixth MEMS sensor 601 for measuring an environmental parameter of a sensor environment.

[0155] Specifically, the sixth MEMS sensor 601 is a variant of the fifth MEMS sensor 501 of Fig. 5, in which the frame structure 113 and R. 414485

[0156] - 22 - of the spring structure 115 together with the SiCh sacrificial layers in the cavern area 153, the SiCh layers present between the layers forming the electrodes 503, 505 and the layers forming the corresponding respectively adjacent membranes 119, 121 were removed.

[0157] Fig. 7 shows a seventh MEMS sensor 701 for measuring an environmental parameter of a sensor environment.

[0158] In the seventh MEMS sensor 701, the layers forming the two electrodes 503 and 505 within the sensing area 111 are not connected to the frame structure 113. This offers the particular technical advantage that the connection of the membrane composite to the surrounding frame structure 113 can be made more elastic / flexible / softer.

[0159] Fig. 8 shows an eighth MEMS sensor 801 for measuring an environmental parameter of a sensor environment.

[0160] The eighth MEMS sensor 801 is a variant of the seventh MEMS sensor 701 of Fig. 7, in which the sensing area 111 is connected to the frame structure 113 only via the layers forming the two electrodes 503, 505. In this variant, the support structures 127 provided between the first membrane 119 and the first electrode 503 as well as between the second membrane 121 and the second electrode 505 are completely closed in the edge region of the membranes 119, 121, and a cavern area 153 is designed to be gas-tight.

[0161] Furthermore, for example, the additional side walls 152 of the frame structure 113 adjacent to the sensing area 111 are completely closed, at least between the layer forming the first membrane 119 and the layer forming the first electrode 503, and at least between the layer forming the second membrane 121 and the layer forming the second electrode 505, in order to prevent, for example, etching of sacrificial layer material in the area of ​​the frame structure during a sacrificial layer etching process. R. 414485

[0162] - 23 -

[0163] Fig. 9 shows a ninth MEMS sensor for measuring an environmental parameter.

[0164] The ninth MEMS sensor 901 is a variant of the eighth MEMS sensor 801 of Fig. 8, wherein the layer structure of the frame structure 113 and the spring structure 115 corresponds to that of the first MEMS sensor 101 of Fig. 1 and wherein the layers that effect an elastic / springy suspension of the sensing area 111 on the frame structure 113 as well as the layers that limit the frame structure 113 and the spring structure 115 in a vertical direction 117 consist of the material of the layers forming the electrodes 503, 505, for example doped silicon.

[0165] Fig. 10 shows a tenth MEMS sensor 1001 for measuring an environmental parameter of a sensor environment.

[0166] The tenth MEMS sensor 1001 is a variant of the fifth MEMS sensor 501 of Fig. 5, wherein the electrical leads to the two electrodes 503, 505 in the sensing area 111 are electrically insulated from each other starting from the anchoring area 109, electrically insulated from structure-limiting side walls 151, electrically insulated from the center electrode structure 125 and its electrical lead(s) and electrically insulated from the membranes 119, 121 respectively the layers forming the membranes 119, 121 through the at least one spring structure 115 and through the frame structure 113.

[0167] The electrical leads for the two electrodes 503, 505 are marked with reference numeral 1003 for the first electrode and with reference numeral 1005 for the second electrode.

[0168] If the center electrode structure 123 has two electrically isolated center electrodes, i.e., a first center electrode and a second center electrode, it is specifically provided that these leads 1003 and 1005 are also electrically insulated from the electrical leads for the two center electrodes 303, 305. R. 414485

[0169] - 24 -

[0170] Fig. 11 shows an eleventh MEMS sensor 1101 for measuring an environmental parameter. The eleventh MEMS sensor 1101 is a variant of the tenth MEMS sensor in Fig. 10, wherein the electrical connections between the frame structure 113 and the electrodes 503, 505 and / or the connections of the additional electrodes 503, 505 to the support structures 127 are made by providing an additional spring structure 1103, 1105, wherein these additional spring structures 1103, 1105 can, for example, consist of the layer or layer system of the additional electrodes 503, 505 and can, for example, be produced locally by at least partially removing the layer and / or layer system of the additional electrodes 503, 505. For example, it may be possible to generate the further spring structures 1103, 1105 by selectively or selectively completely removing the layer or layer system of the additional electrodes 503, 505.

[0171] Furthermore, for example, the connection of the center electrode structure 123, i.e., the single center electrode 125 or the two center electrodes 503, 505, to the frame structure 113 can be elastically formed, either additionally or optionally. Here, too, a corresponding elastic connection can be achieved, for example, by at least partially removing the layer or layer system of the center electrode structure, i.e., the single center electrode 125 or the two center electrodes 503, 505, and / or by partially or completely removing the layer or layer system of the center electrode structure 123.

[0172] For example, it may be provided that the electrical connection between the frame structure 113 and the electrodes 503, 505 and / or the center electrode(s) is made via at least one elastically or resiliently designed conductor track structure.

[0173] By providing at least one spring structure 115 between the frame structure 113 and the anchoring area 109, as described above, it is advantageous, for example, to further reduce the load on the R. 414485.

[0174] - 25 -

[0175] The channel structure penetrating the sensing area 111 can be omitted. Thus, for example, the MEMS sensor can be free of a channel structure penetrating the sensing area 111. Therefore, the sensing area preferably does not have a channel structure penetrating it. Fluidic coupling between an environmental area adjacent to the first membrane and an environmental area adjacent to the second membrane can be achieved, for example, via the free spaces 149 within the layer system 105, which are freed in the area around a spring structure 115.

[0176] Fig. 12 shows a twelfth MEMS sensor 1201 for measuring an environmental parameter. The twelfth MEMS sensor 1201 is a variant of the seventh MEMS sensor 701 shown in Fig. 7. One difference is that the two membranes 119 and 121 each have a bead-shaped or channel-shaped structure 1203 that bridges / covers a gap in the layers forming the membranes 119 and 121, respectively. This structure allows for an even softer / more flexible suspension / connection of the sensing area 111 to the frame structure 113 surrounding the sensing area 111.

[0177] Structure 1203 thus has a corrugated or trough shape. In other words, the two membranes 119 and 121 each have a corrugated or trough shape, respectively: structure 1203. Structure 1203 is located, for example, within the sensing area 111, and here, for example, in the area, adjacent to, or near the frame structure 113, and is, for example, at least partially formed from layers of the layer system 105. Structure 1203 can, for example, be local or be a self-contained structure that follows the contour of the sensing area 111.

[0178] Fig. 13 shows a thirteenth MEMS sensor 1301 for measuring an environmental parameter. The thirteenth MEMS sensor 1301 is a variant of the eighth MEMS sensor 801 shown in Fig. 8. One difference is that the two electrodes 503 and 505 each have a bead-shaped or channel-shaped structure 1303 bridging / covering a gap in the layers forming the electrodes 503 and 505, respectively. This structure is further described in R. 414485.

[0179] - 26 - enables a softer / more flexible suspension / connection of the sensing area 111 to the frame structure 113 surrounding the sensing area 111.

[0180] Structure 1303 thus has a bead or groove shape. In other words, both electrodes 503 and 505 each have a bead or groove: structure 1303. Structure 1303 is located, for example, within the sensing area 111, and here, for example, in the area, adjacent to, or near the frame structure 113, and is, for example, at least partially formed from layers of the layer system 105. Structure 1303 can, for example, be local or be a self-contained structure that follows the contour of the sensing area 111.

Claims

R. 414485 - 27 - Claims 1. MEMS sensor (101) for measuring an environmental parameter of a sensor environment, comprising: a substrate (103), a layer system (105) having several, in particular electrically conductive and / or electrically non-conductive, layers (107), wherein the layer system (105) is divided into at least an anchoring region (109), a sensing region (111), a frame structure (113) surrounding the sensing region (111), and at least one spring structure (115) movably formed between the anchoring region (109) and the frame structure (113), wherein the anchoring region (109) is at least partially arranged on the substrate (103), wherein the frame structure (113) is elastically connected to the anchoring region (109) via the at least one spring structure (115), and wherein one or more, in particular electrically conductive and / or electrically non-conductive, layers (107) of the sensing region (111) are connected to the frame structure (113) are connectedthe sensing area (111) comprising: a first membrane (119) which can be deflected in a vertical direction (117) depending on the ambient size, a second membrane (121) arranged at a distance in the vertical direction (117) from the first membrane (119), mechanically connected to the first membrane (119) and deflectable in the vertical direction (117) depending on the ambient size, such that a deflection of the first membrane (119) is coupled with a deflection of the second membrane (121), a central electrode structure (123) which is arranged between the first and the second membrane (121) at a distance from them. R. 414485 - 28 - 2. MEMS sensor (101) according to claim 1, wherein a layer structure of the at least one spring structure (115) substantially corresponds to the layer structure of the adjacent frame structure (113) and the adjacent anchoring area (109).

3. MEMS sensor (101) according to claim 1 or 2, wherein an electrical supply line for the center electrode structure (123) is provided in a, in particular central, area of ​​the at least one spring structure (115), wherein the electrical supply line is electrically insulated from the layer(s) (131 , 137, 139, 141, 143) flanking and / or limiting the at least one spring structure (115).

4. MEMS sensor (101) according to one of the preceding claims, wherein the layer system (105) comprises at least one support structure (127) arranged between the first membrane (119) and the second membrane (121), mechanically connecting or coupling the first membrane (119) and the second membrane (121) and at least partially penetrating the center electrode structure (123) in a freely movable manner.

5. MEMS sensor (101) according to claim 4, wherein one or more flanking and / or limiting layers of the at least one spring structure (115) consist essentially of the same material composite or comprise such a material composite as the material composite of the at least one support structure (127).

6. MEMS sensor (101) according to one of the preceding claims, wherein one or more flanking and / or limiting layers (131 , 137, 139, 141, 143) of the at least one spring structure (115) are electrically insulated from each other to avoid an electrical short circuit between the first membrane (119) and the second membrane (121).

7. MEMS sensor (101) according to one of the preceding claims, wherein a free space between the anchoring area (109) and / or the frame structure (113) and / or the side wall or side walls (151) facing the at least one spring structure (115) are formed from the same layers and / or layer materials or such layers R. 414485 - 29 - and / or layer materials and / or have essentially the same material composition or consist of such as the at least one spring structure (115).

8. MEMS sensor (101) according to one of the preceding claims, wherein the layer system (105) comprises an electrically insulating layer in a region of one or more side walls (152) which separate a cavern region (153) formed between the first membrane (119) and the second membrane (121) from the frame structure (113) surrounding the cavern region (153), such that the center electrode structure (123) is electrically insulated from the first membrane (119) and the second membrane (121) in the frame structure (113) and extends from there via the at least one spring structure (115) in the anchoring region (109).

9. MEMS sensor (101) according to one of the preceding claims, wherein the at least one spring structure (115) is designed to be stiffer than a suspension of the sensing area (111) on the frame structure (113).

10. MEMS sensor (101) according to one of the preceding claims, wherein at least one of the at least one spring structure (115) and the frame structure (113) each comprises a thickening (205) formed by a substrate part formerly connected with the substrate (203).

11. MEMS sensor (101) according to one of the preceding claims, wherein the center electrode structure (123) comprises a first center electrode (303) and a second center electrode (305) opposite the first center electrode (303) in the vertical direction (117), wherein the first center electrode (303) and the second center electrode (305) are electrically insulated from each other.

12. MEMS sensor (101) according to claim 11 as far as referenced to claim 4, wherein the at least one support structure (127) is electrically conductive, such that the first membrane (119) and the second membrane (121) are electrically conductively connected to each other via the at least one support structure (127). R. 414485 - 30 - 13. MEMS sensor (101) according to one of the preceding claims, the sensing area (111) further comprising as layers: a first electrode (503) which is arranged between the first membrane (119) and the center electrode structure (123) spaced apart from these, such that a first capacitor structure is formed by the first electrode (503) and the center electrode structure (123), and a second electrode (505) which is arranged between the second membrane (121) and the center electrode structure (123) spaced apart from these, such that a second capacitor structure is formed by the second electrode (505) and the center electrode structure (123).

14. MEMS sensor (101) according to claim 13, wherein the sensing area (111) is connected to the frame structure (113), in particular only via the first electrode (503) and / or the layer forming the second electrode (505).

15. MEMS sensor (101) according to claim 13 or 14, wherein one or more electrical leads (1003, 1005) to the first electrode (503) and / or to the second electrode (505) in the sensing area (111) extending from the anchoring area (109) are electrically insulated from each other, electrically insulated from structure-limiting side walls (151), electrically insulated from the layer(s) forming the center electrode structure (123), and electrically insulated from the first membrane (119) and electrically insulated from the second membrane (121) by the spring structure (115) and by the frame structure (113).

16. MEMS sensor (101) according to one of the preceding claims, wherein the sensing area (111) is connected to the frame structure (113), in particular only via the first membrane (119) and / or the layer forming the second membrane (121).

17. MEMS sensor (101) according to one of the preceding claims, insofar as it relates back to claim 13, wherein the electrodes (503, 505) in the sensing area (111) are electrically insulated from the at least one side wall of the cavern area by means of at least one further R. 414485 - 31 - surrounding layer system (105) elastically or flexibly designed spring structure (1103, 1105) are electrically contacted.

18. MEMS sensor (101) according to one of the preceding claims, wherein the two membranes (119, 121) each have a bead-shaped structure (1203) bridging a break in the layers forming the membranes (119, 121).

19. MEMS sensor (101) according to one of the preceding claims as far as referenced to claim 13, wherein the two electrodes (503, 505) each have a bead-shaped structure (1303) bridging a break in the layers forming the electrodes (503, 505).

20. MEMS sensor (101) according to claim 18 or 19, wherein the respective corrugated structure (1203, 1303) consists of or comprises a material of the layers forming the membranes (119, 121) and / or of a material of the layers forming the electrodes (503, 505) and / or of a material of a layer forming a dielectric layer (131) of the layer system (105) and designed to be etch-resistant to a sacrificial layer etching medium.

21. MEMS sensor (101) according to any of the preceding claims, wherein is a pressure sensor, a microphone, a combination of both, and / or is designed as a MEMS transducer.

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