Microelectromechanical sensor component and sensor with a microelectromechanical sensor component

Abstract

The invention relates to a microelectromechanical sensor component (1) for detecting a measured variable (M), wherein the sensor component (1) has a support structure (2) and a microsensing unit (3) arranged on the support structure (2) and having a sensing region (4), wherein the support structure (2) has an outer surface (6) facing an environment (5) of the sensor component (1), and wherein a heat-conducting element (7) for influencing a temperature gradient (G) of the sensor component (1) is arranged on the outer surface (6). The invention further relates to a sensor (20) having a microelectromechanical sensor component (1).

Description

The invention relates to a microelectromechanical sensor component and a sensor having a microelectromechanical sensor component.Prior ArtMicroelectromechanical sensor components, also known under the term MEMS sensor components, and sensors with microelectromechanical sensor components are known from the prior art.U.S. Pat. No. 11,485,630 B2 describes a micromechanical sensor having a substrate, a cap element, a seismic mass deflectable orthogonally with respect to the cap element, and a cavity having an internal pressure lowered with respect to the environment, the sensor having compensating means which are designed to provide a homogenization of a temperature gradient field in the cavity during operation of the micromechanical sensor.Disclosure of the InventionAccording to the features of independent claim 1, a microelectromechanical sensor component for detecting a measured variable is proposed, wherein the sensor component has a carrier structure and a microsensing unit, which is arranged on the carrier structure and has a sensing region, wherein the carrier structure has an outer surface facing a vicinity of the sensor component, and wherein a heat-conducting element for influencing a temperature gradient of the sensor component is arranged on the outer surface.A microelectromechanical sensor component according to the proposed features has the advantage of a temperature distribution over the sensor component that can be influenced in a targeted manner, for example homogeneously, by means of which the temperature gradient in the sensing region of the sensor component can also be advantageously influenced, in particular evened out, in a simple manner. In this case, the temperature gradient in the sensing region can be equalized indirectly via the influencing of the temperature gradient on the carrier structure of the sensor component, without, for example, suitable temperature control or compensating means having to be placed directly in the sensitive sensing region or, in a complicated manner, in a cavity of the microsensing unit. By means of the comparatively large outer surfaces of the carrier structure measured at the sensing region, an accelerated homogenization of the temperature distribution can additionally be achieved. Furthermore, the avoidance of nonlinear effects or effects of a higher order is supported, which can result from an interaction of the thermal gradient with different materials of the sensor component having different properties.With the microelectromechanical sensor component according to the proposed features, more precise measurement results of the measured variable are obtainable on the basis of the temperature gradient of the sensor component that can be specifically influenced. In particular, the thermal influence on measurement results is reduced, which may be caused, for example, by temperature-dependent non-linearities and / or interference effects in the sensor behavior. In particular, more accurate temperature compensation of the measurement results is made possible since location-dependent temperature changes within the sensor component and the sensing region are reduced. Furthermore, correspondingly more accurate test and calibration results can be achieved. A further advantage results from the increase of a service life of the sensor component by a more uniform thermal load, which can lead to reduced stress effects on different components of the sensor component.A microelectromechanical sensor component may be a component having mechanical and electrical microstructures, for example having microstructures having dimensions in the micro- and / or nanometer range. The sensor component can be produced, for example, in semiconductor technology, in particular on a silicon basis. In particular, the mechanical and electrical microstructures can consist of polycrystalline and / or doped silicon and / or silicon compounds. Due to their dimensioning, microelectromechanical sensor components can be used in miniaturized sensor modules and can be suitable for use in mobile terminals, for example.A measurement variable detectable by means of the microelectromechanical sensor component can be, for example, a physical measurement variable, in particular an environmental condition of the sensor component such as a pressure, an air humidity or a temperature. Further detectable measurement variables can relate, for example, to kinematic measurement variables, for example, an acceleration. The measurement variable can be detectable by a physical interaction of the microsensing unit with the environment of the sensor component.A support structure of the sensor component may form a mechanical base or a mechanical frame structure of the microsensing unit. The support structure can be configured to support or hold the microsensing unit in space. Furthermore, the carrier structure can form mechanical components of the microsensing unit, for example boundary surfaces of a cavity of the microsensing unit. The support structure furthermore enables a mechanical support and spacing of the microsensing unit with respect to adjacent components, for example with respect to a sensor housing or a signal processing unit of a sensor having the sensor component. In addition, the support structure assumes a protective function for the microsensing unit with respect to external influences. The carrier structure can additionally form a carrier for electrical connection structures of the sensor component, for example for conductor tracks or bond pads. Depending on the measuring principle of the sensor component, the support structure can have at least one interior cavity, which can be formed in particular adjacent to a micromembrane of the microsensing unit. According to one possible configuration of the microelectromechanical sensor component, the carrier structure can be produced from silicon, in particular monocrystalline silicon.A microsensing unit of the sensor component can be or have a microstructural measuring device, for example an elastically deflectable micromembrane or a displaceable microschweizing mass. A deflection or displacement of the measuring device can be detected, for example, capacitively, piezoelectrically or optically and converted into an electrical measurement signal. A sensing region of the microsensing unit can be a section of the microsensing unit that is sensitive to the measurement variable, for example a deflectable region of a micromembrane. Depending on the measuring principle of the sensor component, the sensing region can be in atmospheric communication with the surroundings of the sensor component, for example via a pressure access channel provided for this purpose, or can be arranged in a closed cavity, for example for the precise measurement of accelerations.A vicinity of the sensor member may be a space surrounding the sensor member. For example, a space of a sensor accommodating the sensor component, which space is delimited by a sensor housing, can already be understood as the environment of the sensor component. In the case of an exposed sensor component, the surroundings of the sensor component can be formed by the free atmosphere.An outer surface of the carrier structure facing the environment of the sensor component can be an outer surface of the carrier structure. Depending on the specific configuration of the sensor component and, if appropriate, on a present arrangement of the sensor component in a superordinate component system, surface sections of the outer surface can be exposed or covered by an adjoining component. For example, the sensor component can be connected via a part of its outer surface to a signal processing unit of a sensor, so that this part of the outer surface can be covered at least in sections. The heat-conducting element arranged on the outer surface according to the proposed features can be arranged on covered and / or on exposed parts of the outer surface. Depending on the geometric shape of the sensor component, the outer surface can be formed by a plurality of outer sides. For example, in the case of a cuboidal configuration of the sensor component, an upper side, an underside and side surfaces running between the upper side and the underside can form the outer surface of the sensor component. The microsensing unit of the sensor component can be arranged, for example, on an upper side of the carrier structure or, for example, in the case of a microsensing unit embedded in a depression of the carrier structure, closer to an upper side than to an underside of the carrier structure. The carrier structure or its outer surface can have a defined depth and form a volume body.A heat-conducting element can be an in particular passive structural element with a defined thermal conductivity, which can in particular be higher than the thermal conductivity of the carrier structure. In principle, it is not excluded to configure the heat-conducting element as an active structural element that can be supplied with current, for example, in order to enable a targeted local temperature control of the carrier structure by means of the heat-conducting element as required.A temperature gradient, also referred to as a thermal gradient, corresponds to a directed physical variable which describes the location dependence of the temperature. A temperature gradient can accordingly be understood to mean a spatial change in the temperature. A temperature gradient can be described, for example, in Kelvin per meter. In the present case, the temperature gradient can be regarded in a simplified manner as a temperature gradient within the sensor component from a warmer component region to a colder component region. The temperature gradient of the sensor component can be influenced by means of the heat-conducting element, in particular, in such a way that a more homogeneous temperature distribution is achieved. Accordingly, the use of the heat-conducting element aims in particular to equalize or reduce the temperature gradient over the extent of the sensor component.The heat-conducting element can be arranged on the outer surface of the support structure in particular in such a way that at least one outer side of the outer surface is at least partially covered by the heat-conducting element, for example to an extent of at least 20%, to an extent of at least 40% or to an extent of at least 80% of the outer side. According to advantageous embodiments, full-area coverings of at least one outer side of the outer surface can also be provided. By means of a skillful, individually coordinated design of the heat-conducting element with regard to its shape, thermal conductivity and positioning on the carrier structure, compensation of known heat sources in the environment of the sensor component or in predefined thermal situations can be optimized.According to one embodiment, the heat-conducting element can comprise a heat-conducting material having a specific heat conductivity of between 200 and 500 W / mK. In particular, the heat-conducting element can have a heat-conducting material with a specific thermal conductivity of between 250 and 450 W / mK, in particular between 300 and 400 W / mK. The specific thermal conductivity, also referred to as the thermal conductivity coefficient, can be understood to mean a material property that determines the heat flow through a material on the basis of thermal conduction. Compared to the aforementioned heat conductivity regions, silicon, which is a frequently used material for support structures of microelectromechanical sensor components, for example, has a thermal conductivity of approximately 150 W / mK and accordingly a lower thermal conductivity than the provided heat-conducting element. A specific thermal conductivity of the heat-conducting element in one of the aforementioned value ranges allows an effective influencing of the temperature gradient of the microelectromechanical sensor component via its outer surface and can be economically implemented using readily available materials.According to one embodiment, the heat conducting element can be made of a metal or of a metal alloy. Metals and metal alloys are well available materials with favorable thermal conduction properties. A heat conducting element made of a metal or a metal alloy can be produced easily and, for example, optionally produced using a classic metal processing method and applied to the carrier structure or produced directly on the carrier structure using a MEMS production method.According to a development of the embodiment described above, the heat-conducting element can be produced from gold or from an aluminum-copper alloy. Gold and an aluminum-copper alloy are a metal and a metal alloy with very good heat conducting properties, are easily processable and also have a high thermal and chemical resistance. Gold and aluminum-copper alloys can also be connected to further structural units on the sensor component by process technology or in the shape, for example to connection pads for bond wires, markings, signal lines or further sensor elements, which can enable, for example, an accompanying temperature measurement on the sensor component.According to one embodiment, the heat-conducting element can be designed as a heat-conducting plate. A heat-conducting plate represents a robust heat-conducting element which can be produced easily and which additionally increases a mechanical stability of the carrier structure. A heat-conducting plate can be a planar, coherent structural element which is placed on the outer surface of the carrier structure, in particular is connected to the latter mechanically or in a materially bonded manner. The heat conducting plate may be a substantially rigid mechanical structural element. The heat-conducting plate can rest flat on the outer surface. The heat-conducting plate can form a mechanical cover of the carrier structure. According to one possible embodiment, the heat-conducting plate can be designed as a thin metal sheet. A shape and dimensioning of the heat-conducting plate can advantageously correspond to the shape and dimensioning of the outer side of the outer surface to which the heat-conducting plate is applied, so that the outer side and the heat-conducting plate lie substantially congruently one on the other. According to one possible configuration, the heat-conducting plate can have an intermediate medium, such as a highly viscous heat-conducting paste or an adhesive layer. If the heat-conducting plate is arranged on an outer side having the microsensing unit, for example on the upper side, the heat-conducting plate can have a sensing opening which is substantially congruent with the sensing region of the microsensing unit, with the result that the sensing region is not covered or impaired by the heat-conducting plate.According to one embodiment, the heat-conducting element can be designed as a heat-conducting coating. A heat-conducting coating can be a heat-conducting element in the form of a materially bonded coating on the outer surface of the carrier structure. The heat-conducting coating can be formed, for example, as a continuous metallic coating or as a coating with a carrier substance and metallic particles distributed therein. A heat-conducting coating can advantageously be applied to the sensor component during the production of the latter within the scope of a sub-process of a MEMS production method. Depending on the outer side of the support structure to be coated, it is conceivable here that the sensor component is brought into different orientations at the processing location, for example rotated by 90° or 180°, so that for example a side surface or an underside of the support structure can also be coated. A heat-conducting coating on the support structure can be formed very thin, so that a material saving and an economic advantage can be obtained compared to rigid structural elements as heat-conducting elements. Furthermore, it is conceivable to connect a coating process for applying the heat-conducting coating to the carrier structure in a meaningful manner to further process steps such as plasma treatments, by means of which the surface or surface properties of the sensor component can be advantageously influenced.According to one embodiment, the heat-conducting element can be designed as a heat-conducting cap. A heat conducting cap can be a cover with a circumferential cap edge, by means of which a cap cover of the heat conducting cap can be spaced apart from the outer surface. The cap cover can extend, for example, parallel to the outer surface and differ in the spacing from a heat conducting plate contacting the outer surface in a planar manner. The cap cover and the cap rim of the heat conducting cap can enclose an inner volume with the outer surface. With a heat conducting element designed as a heat conducting cap, an improved heat distribution on the sensor component can be achieved, since heat from a warmer component region can be rapidly distributed over the entire sensor component via the heat conducting cap. Furthermore, heat convection and radiation at the sensor component can be reduced and an advantageous effect on the temperature gradient can thereby be achieved.According to a development of the embodiment described above, the heat-conducting cap can be arranged on an outer side of the carrier structure in such a way that the heat-conducting cap at least partially spans the sensing region of the microsensing unit. In other words, the heat conducting cap can cover the sensing region in a bridge-like manner. At least partial spanning implies that the heat conducting cap does not have to cover the sensing region over its entire width, for example, or that the heat conducting cap can also have a cap opening, for example a larger central cap opening or a plurality of smaller, decentral cap openings. Such cap openings can form, for example, a pressure access structure of the heat conducting cap in order to enable or improve an interaction of the sensing region with the environment. By means of a heat conducting cap which extends over the sensing region at least in sections, the temperature gradient can be advantageously influenced, in particular homogenized, close to the sensing region without mechanically or electrically impairing the sensing region. In addition, this increases mechanical protection of the sensing region and reduces the risk of contamination as a result of particles entering the sensing region. Furthermore, the heat conducting cap contributes to a reduction of convection in the sensing region, so that a homogenization of the temperature gradient is promoted.According to one embodiment, the sensor component can have a layer structure arranged on a substrate or in a material block, and at least one layer of the layer structure can be formed as a heat-conducting layer. The substrate can be, for example, a silicon wafer. The material block may be a silicon block, for example. The layer structure can be produced for producing mechanical and electrical microstructures of the sensor component, wherein, for example, at least some layer regions of the layer structure can be locally removed in order to form microstructures or cavities in the layer structure. A continuous metallic layer can be integrated into the layer structure as a heat conducting layer, for example. This allows an additional, improved heat conduction not only on the outer surface of the carrier component, but also via the inner structure of the sensor component. According to one possible configuration, the heat-conducting layer can be present in particular in addition to an existing heating element and be distinguishable therefrom, for example by spatial spacing and / or in that the heat-conducting layer does not have an electrical connection structure. By applying a heat-conducting layer within the scope of a MEMS production method of the sensor component to the substrate or to a layer of the layer structure or by introducing a heat-conducting layer within the scope of a MEMS production method of the sensor component into the material block, the production of the heat-conducting layer can be integrated in a simple manner into the production process of the sensor component.According to one embodiment, the sensor component can have at least two identical or different heat-conducting elements which are designed as a heat-conducting plate, as a heat-conducting coating, as a heat-conducting cap or as a heat-conducting layer. The terms "identical" and "different" refer here to the mentioned possible embodiments of the heat-conducting element. In other words, it is conceivable to combine the same and / or different embodiments of the heat-conducting elements on the sensor component in a meaningful manner in order to be able to achieve a particularly rapid and efficient influencing, in particular homogenization, of the temperature gradient via the sensor component.According to one embodiment, the sensor component can have an electrically controllable heating element. Accordingly, a heating structure arranged on or in the sensor component can be provided for the active temperature control of regions of the sensor component, in particular of the sensing region. The electrically actuatable heating element can be used for the active temperature control of component regions of the sensor component, in particular of the sensing region, in order, for example, to ensure defined measurement conditions or to enable measurements of specific temperature-dependent measurement variables such as, for example, moisture. The electrically actuatable heating element can furthermore be used for test and calibration functions in order to be able to achieve particularly precise test and calibration results on the sensor component. Especially for sensor components with an integrated heating function, the heating element of which can introduce thermal energy into the sensor component in a spatially limited manner, the heat-conducting element can advantageously contribute to the homogenization of a temperature gradient across the sensor component according to the proposed features.According to one embodiment, the sensor component can comprise a heat-conducting fluid and / or a heat-insulating fluid. A heat-conducting fluid can be a liquid, a gas or a liquid-gas mixture with a high specific thermal conductivity, which can be in particular higher than the specific thermal conductivity of the carrier structure. A thermal insulation fluid can be a liquid, a gas or a liquid-gas mixture with a low specific thermal conductivity, which can in particular be lower than the specific thermal conductivity of the carrier structure. The heat-conducting fluid and / or the heat-insulating fluid can be arranged, for example, in each case in a closed chamber in the sensor component and serve locally there for a targeted heat conduction or heat insulation, wherein the respective position of the chambers can be selected, for example, as a function of known heat sources or heat effects in the environment of the sensor component. To introduce the heat conducting fluid and / or the heat insulating fluid into such a chamber, an open chamber can be produced in each case during the production process of the sensor component, the chamber can be filled with the heat conducting fluid or heat insulating fluid and a liquid- or gas-tight closure of the chamber can subsequently be produced. Alternatively or additionally to a chamber accommodating the heat-conducting fluid or heat-insulating fluid, a sponge body can be formed in the sensor component and provided for concentrated accommodation of the heat-conducting fluid or the heat-insulating fluid. With a heat-conducting fluid and / or a heat-insulating fluid, a supplementary possibility arises for specifically influencing the temperature gradient via the sensor component.According to one embodiment, the sensor component can have a heat-conducting body arranged in particular within the carrier structure and / or a heat-insulating body arranged in particular within the carrier structure. The heat-conducting body and / or the heat insulation body can in particular comprise a semiconductor material, in particular silicon. The semiconductor material can differ in particular from the material of the carrier structure, for example with regard to crystallinity or composition. If the carrier structure is produced from a monocrystalline silicon, for example, the heat-conducting body and / or the heat insulation body can be produced from a polycrystalline silicon or from a silicon compound such as silicon dioxide or silicon nitride, for example. The heat-conducting body can have a higher specific thermal conductivity than the support structure. The thermal insulation body can have a lower specific thermal conductivity than the carrier structure. With a heat-conducting body and / or heat-insulating body, the influence on the thermal gradient of the sensor component can be further improved, for example in order to compensate for the influence of heat sources on the sensor component.The invention also relates to a sensor having a microelectromechanical sensor component according to one of the features described above, wherein the sensor has a signal processing unit, which is electrically connected to the sensor component, for applying and processing signals of the sensor component. The proposed sensor can also be used to achieve the advantages described above of a specifically influenceable, for example homogenousizable, temperature distribution over the sensor component and more accurate measurement, test and calibration results resulting therefrom, and an increased lifetime of the sensor component. The signal processing unit of the sensor provides further possibilities for amplifying the described positive effects, as will be explained in more detail below in connection with advantageous embodiments. In addition, the combination of the sensor component with an electrically connected signal processing unit results in an operational sensor unit with control and evaluation functions.A signal processing unit can be understood as a control circuit which can be designed in particular as an integrated circuit, for example as an ASIC (application specific integrated circuit). The signal processing unit can serve for the actuation of the sensor component and for the reception and optionally also for the evaluation of sensor signals of the sensor component. The signal processing unit can be electrically coupled to the sensor component by means of suitable electrical connection structures, for example by means of bonding wiring.According to one embodiment, the sensor component can be connected to the signal processing unit by a cohesive connection means having a heat-conducting structure. The material-bonded connection means can be an adhesive, for example. The heat-conducting structure of the connecting means can be formed, for example, by particles with good thermal conductivity, for example metal particles or graphite particles or, for example, metal fibers or graphite fibers, which are distributed in the connecting means. The cohesive connecting means having the heat-conducting structure can have a thermal conductivity which is higher than the thermal conductivity of the carrier structure of the sensor component. It can be provided in particular that the sensor component is connected to the signal processing unit in a materially integral manner over at least 20%, at least 40%, at least 80% or over the entire surface of an outer side of the sensor component facing the signal processing unit. Accordingly, a planar connection of the sensor component to the signal processing unit may be provided in delimiting from point-wise, for example soldered, connection points. With a connection of the sensor component to the signal processing unit by a cohesive connection means having a heat-conducting structure, a simple and economic possibility of an improved temperature distribution over the outer surface of the sensor component can be provided. By connecting the sensor component to the signal processing unit, a mechanical fixing of the otherwise potentially free-floating sensor component can be made possible. The connecting means in this case performs a plurality of functions with regard to the cohesive connection of the components to one another and to an improved heat conduction on the outer surface of the sensor component. In addition, the material-bonded connection means can serve for decoupling external stresses.According to an embodiment, the signal processing unit may comprise a heating unit. This makes it possible to provide a supplementary possibility for specifically influencing the temperature gradient on the sensor component. The heating unit can be a heating structure arranged on the signal processing unit for actively tempering a component region of the sensor component connected to the signal processing unit. The heating unit can be arranged in particular on an outer surface of the signal processing unit facing the sensor component. In the case of a connection of the sensor component to the signal processing unit by means of a materially bonded connecting means, the heating unit can be in a thermally conductive contact via the connecting means with the outer surface of the sensor component opposite the heating unit. Advantageously, the connecting means can have a heat-conducting structure as described above, so that the thermal energy transmitted by the heating unit can be distributed optimally over the materially bonded connection region. According to one possible embodiment, a plurality of heating units distributed over the outer surface of the signal processing unit facing the sensor component can be arranged on the signal processing unit in order to actively temperature control different regions of the sensor component and thus to be able to contribute to a targeted influencing of the temperature gradient in a plurality of component regions of the sensor component. The plurality of heating units can be individually controllable in particular in order to enable a temperature control of the sensor component that is precisely matched to the temperature gradient of the sensor component and coordinated with one another. According to a further possible embodiment, the heating unit can be arranged spaced apart from an electrical connection structure, for example a wire bond connection between the signal processing unit and the sensor component. As a result, a heat circuit can be formed by the sensor component between the heating unit and the connection structure, which is likewise advantageously thermally conductive because of its usually metallic structure, via the selected distance. The thermal circuit can help to equalize the temperature gradient by the sensor component.According to one embodiment, the signal processing unit can have a temperature sensor for regulating a heating power of the heating unit.This allows very precise active influencing of the temperature gradient. A local temperature value can be detected by the temperature sensor and a temperature gradient present in the sensor component can be deduced, which temperature gradient can be very finely influenced by means of the controllable heating power and monitored via the temperature sensor. According to one possible embodiment, a plurality of temperature sensors distributed spatially over the signal processing unit can be arranged on the signal processing unit in order to be able to detect and monitor the spatial temperature distribution in the region of the sensor component even more precisely. In this way, in particular in combination with a plurality of heating units, individual local temperature control of the sensor component can be made possible and accordingly a homogenization of the temperature gradient can be actively influenced, in particular in the form of a control circuit which uses temperature signals of the temperature sensors for controlling the heating units.According to one specific embodiment, the sensor may be designed as an environmental sensor. An environmental sensor may be configured to measure environmental conditions. According to one possible embodiment, the sensor can be designed as a pressure sensor. Environmental sensors, in particular environmental sensors with microelectromechanical sensor components, frequently exhibit a high temperature sensitivity. In particular, thermally induced deviations of the measurement signal may be possible even in the case of small location-dependent temperature changes. Against this background, the proposed heat conducting concept for influencing the temperature gradient at the sensor component of the sensor can be used in a meaningful manner and with a high advantageous effect in an environmental sensor.In the context of this application, the words "a / an", unless expressly defined otherwise, are not to be understood as a numerical word, but rather as an indeterminate article having the word sense of "at least one / one".The invention permits various embodiments and is explained in more detail below on the basis of exemplary embodiments with the accompanying drawings. They show in a schematic, simplified manner: FIG. 1 shows a sensor having a microelectromechanical sensor component and a signal processing unit according to a first embodiment in a perspective front view; FIG. 2 shows a sensor having a microelectromechanical sensor component and a signal processing unit according to a second embodiment in a perspective front view; FIG. 3 shows a sensor having a microelectromechanical sensor component and a signal processing unit according to a third embodiment in a perspective front view; FIG. 4 shows a sensor having a microelectromechanical sensor component and a signal processing unit according to a fourth embodiment in a perspective front view; FIG. 5 shows a sensor having a microelectromechanical sensor component and a signal processing unit according to a fifth embodiment in a perspective front view; FIG. 6 shows a sensor having a microelectromechanical sensor component and a signal processing unit according to a sixth embodiment in a perspective front view; FIG. 7 is a front view of the sensor according to the first embodiment with the sensor component and the signal processing unit in a state connected to one another; FIG. 8 shows a sensor according to a seventh embodiment with the sensor component and the signal processing unit in a state connected to one another in a front view; FIG. 9 is a front view of the sensor according to the fifth embodiment with the sensor component and the signal processing unit in a state connected to one another; and FIG. 10 shows an enlarged view of a microelectromechanical sensor component for a pressure sensor according to an exemplary embodiment in a schematic sectional illustration.FIGS. 1 to 10 show, on the basis of schematic schematic sketches, sensors 20 with microelectromechanical sensor components 1 and signal processing units 21 in different views. For ease of understanding and for improved clarity, the sensor components 1 and the signal processing units 21 are spaced apart from one another in FIGS. 1 to 6 and are illustrated in all figures with the exclusion of peripheral structures such as, for example, bonding wires, substrate or the sensor package.FIG. 1 schematically shows a sensor 20 having a microelectromechanical sensor component 1 and a signal processing unit 21 according to a first embodiment. The sensor component 1 serves for the detection of a measured variable M, as is illustrated by way of example in FIG. 10 as ambient pressure p. According to the exemplary embodiments shown in FIGS. 1 to 10, the sensor 20 is designed as an environmental sensor 20' and the sensor component 1 is configured to record a measured variable M of an environment 5 of the sensor component 1.The sensor component 1 has a carrier structure 2 and a microsensing unit 3 arranged on the carrier structure 2 and having a sensing region 4. The support structure 2 forms a mechanical base and frame structure of the microsensing unit 3 and supports it in space. Furthermore, the carrier structure 2 forms a carrier for electrical connection structures, not shown in detail, of the sensor component 1, via which the microsensing unit 3 is electrically connectable or connected to the signal processing unit 21. The carrier structure 2 can be made of a semiconductor material, in particular silicon. The microsensing unit 3 is a microstructural measuring device of the sensor component and can be designed, for example, as shown in FIG. 10, as an elastically deflectable micromembrane 14.The carrier structure 2 has an outer surface 6 facing the environment 5 of the sensor component 1, which forms an outer surface of the carrier structure 2. According to the exemplary embodiment shown, the support structure 2 is present as a rectangular solid body. The outer surface 6 of the support structure 2 is accordingly divided into a plurality of outer sides 6' which form an upper side 6a, a lower side 6b and side surfaces 6c of the support structure 2 connecting the upper side 6a to the lower side 6b. According to the exemplary embodiment shown, the microsensing unit 3 is arranged on the upper side 6 aof the carrier structure 2.A heat conducting element 7 for influencing a temperature gradient G of the sensor component 1 is arranged on the outer surface 6 of the carrier structure 2. According to the exemplary embodiment shown in FIG. 1, the heat-conducting element 7 is arranged on an exposed side surface 6 cof the carrier structure 2 and covers the latter substantially over the entire surface and substantially congruently. According to the exemplary embodiment shown in FIG. 1, the heat-conducting element 7 is designed as a heat-conducting plate 7 a. The heat-conducting plate 7 aconstitutes a planar mechanical structural element which, according to the exemplary embodiment, is applied to a side surface 6 cof the carrier structure 2 and rests planar on the outer surface 6. In this case, the heat-conducting plate 7 aconstitutes a cover of the support structure 2 on its side surface 6 c. According to one possible configuration, the heat-conducting plate 7 acan have a highly viscous heat-conducting paste or an adhesive layer for fastening.The heat-conducting element 7 can be considered a passive structural element with a defined thermal conductivity, wherein the specific thermal conductivity of the heat-conducting element 7 is in particular higher than the specific thermal conductivity of the carrier structure 2. For example, the heat-conducting element 7 can have a specific thermal conductivity of between 200 and 500 W / mK. For this purpose, the heat-conducting element 7 can be produced, for example, from a metal, for example gold, or from a metal alloy, for example an aluminum-copper alloy. According to alternative embodiments, the heat-conducting element 7 can also be designed as an active structural element that can be supplied with current in order to be able to implement a targeted active temperature control.By means of the heat conducting element 7, a temperature distribution over the sensor component 1 that can be specifically influenced, for example homogenized, can be achieved. As a result, a temperature profile in the temperature-sensitive sensing region 4 can also be equalized, as a result of which more precise measurement results can be achieved with the microsensing unit 3. By means of the heat conducting element 7 arranged on the outer surface 6 of the support structure 2, a rapid homogenization can be achieved and the sensing region 4 can be kept free of temperature control and compensating means. In addition, non-linear effects and effects of a higher order due to an interaction of the temperature gradient G with different materials of the sensor component 1 are avoided. By reducing location-dependent temperature changes at the sensor component 1, more precise temperature compensation can be effected and more precise test and calibration results can be obtained. As a result of a resulting more uniform thermal stress of the sensor component 1 with reduced stress effects, the durability and service life of the sensor component 1 can be increased.The sensor 20 includes a signal processing unit 21 in addition to the sensor component 1. The signal processing unit 21 is electrically connected to the sensor component 1 via electrical connection elements, not shown in detail, for example by means of bonding wiring, and is configured for applying and processing signals of the sensor component 1. The signal processing unit 21 can be designed, for example, as an ASIC. Contrary to the illustration shown, the sensor component 1 can be arranged directly on the signal processing unit 21 and be connected thereto mechanically or in a materially integral manner. According to a non-limiting example for illustrating sensor dimensions, for example, the signal processing unit 21 may have a height of approximately 160 μm, the sensor component may have a height of approximately 220 μm, and a layer height of a cohesive connection means 22 may be approximately 75 μm. The signal processing unit 21 has a heating unit 23, by means of which a simple possibility for targeted active influencing of the temperature gradient G on the sensor component 1 is provided. The heating unit 23 can be arranged on an outer surface 27 of the signal processing unit 21 facing the sensor component 1, as shown.FIG. 2 schematically shows a sensor 20 designed as an environmental sensor 20' with a microelectromechanical sensor component 1 and a signal processing unit 21 according to a second embodiment. The second embodiment is based essentially on the first embodiment with regard to the structure and the functioning of the sensor 20. In contrast to the first embodiment, a heat-conducting element 7 is arranged on the support structure 2 on its side surfaces 6 c, which heat-conducting element is designed as a heat-conducting coating 7 b. The heat-conducting coating 7 bmay be a cohesive coating on the outer surface 6 of the carrier structure 2. Depending on the embodiment, the heat-conducting coating 7 bmay be embodied, for example, as a continuous metallic coating or as a coating with a carrier substance and metallic particles distributed therein. The heat-conducting coating 7 bmay advantageously have been applied to the carrier structure 2 during the production of the sensor component 1 within the scope of a MEMS production method, wherein the coating could optionally also be used, for example, to carry out a plasma treatment of the outer surface 6 of the carrier structure 2 in order to optimize the surface properties of the sensor component 1.FIG. 3 schematically shows a sensor 20 designed as an environmental sensor 20' with a microelectromechanical sensor component 1 and a signal processing unit 21 according to a third embodiment. The third embodiment is based essentially on the first embodiment with regard to the structure and the functioning of the sensor 20. In contrast to the first embodiment, the heat-conducting element 7 embodied as a heat-conducting plate 7 ais not arranged on a side surface 6 cbut on the upper side 6 aof the carrier structure. This also allows a favorable influencing of the temperature gradient G to be achieved, wherein this takes place close to the microsensing unit 3, without, however, impairing this by compensating structures arranged directly in the sensing region 4. Due to its arrangement on the upper side 6 aof the carrier structure 2 having the microsensing unit 3, the heat-conducting plate 7 ahas a sensing opening 7 a- 1 congruent with the sensing region 4 of the microsensing unit 3, such that the sensing region 4 is not covered or impaired by the heat-conducting plate 7 a.FIG. 4 illustrates, on the basis of a fourth embodiment of the sensor 20, that, for example, the second and third embodiments can be combined with one another in a meaningful manner in accordance with the features described above. By means of a heat-conducting coating 7 barranged on the side surfaces 6 band a heat-conducting plate 7 aarranged on the upper side 6 a, the advantages of different heat-conducting elements 7 distributed onto the outer surface 6 of the support structure 2 can be combined and a more rapid homogenization of a temperature gradient G can be achieved. In principle, combinations of identical heat-conducting elements 7 can also be implemented, for example heat-conducting coatings 7 bon the top side 6 aand on the side surfaces 6 cor heat-conducting plates 7 aon the top side 6 aand on the side surfaces 6 c. Furthermore, the combinations can also include further embodiments of the heat-conducting element 7 described in more detail below.FIG. 5 schematically shows a sensor 20 designed as an environmental sensor 20' with a microelectromechanical sensor component 1 and a signal processing unit 21 according to a fifth embodiment. The fifth embodiment is based essentially on the first embodiment with regard to the structure and the functioning of the sensor 20. In contrast to the first embodiment, the heat-conducting element 7 is designed as a heat-conducting cap 7 c. The heat conducting cap 7 cis arranged here on an outer side 6', here on the upper side 6 aof the support structure 2, in such a way that the heat conducting cap 7 cextends over the sensing region 4 of the microsensing unit 3 at least in sections. The heat conducting cap 7 cherein comprises a cap opening 7 c- 1, via which an interaction between the sensing region 4 and the environment 5 of the sensor component 1 is made possible. As can be seen, for example, when viewing FIG. 5 in conjunction with the front view in FIG. 9, the heat-conducting cap 7 ccomprises a cap cover 7 c- 2 and a circumferential cap edge 7 c- 3, wherein the cap cover 7 c- 2 runs at a distance from the outer surface 6 by the cap edge 7 c- 3 and therefore differs from a heat-conducting plate 7 athat makes planar contact with the outer surface 6. As seen in FIG. 9, cap ceiling 7 c- 2, cap rim 7 c- 3, and outer surface 6 include an inner volume. With a heat conducting cap 7c, heat can be distributed very quickly and simultaneously gently over the sensor component 1, in particular over the sensing region 4. At the same time, heat convection and heat radiation at the sensor component 1 are reduced and an advantageous effect on the temperature gradient G is achieved as a result. In addition, mechanical protection of sensing region 4 is increased and a risk of contamination due to the entry of particles into sensing region 4 is reduced.Furthermore, it is illustrated on the sensor 20 according to the fifth embodiment that the heating unit 23 of the signal processing unit 21 is arranged spaced apart from an electrical connection structure 25 of the signal processing unit 21, for example a bonding surface for forming a wire bond connection to the sensor component 1. In this case, a thermal circuit 26 can be formed by the sensor component 1 between the heating unit 23 and the electrical connection structure 25 over a selected distance A between the heating unit 23 and the electrical connection structure 25, and a homogenization of the temperature gradient G by the sensor component 1 can thereby be additionally supported.FIG. 6 schematically shows a sensor 20 designed as an environmental sensor 20' with a microelectromechanical sensor component 1 and a signal processing unit 21 according to a sixth embodiment. The sixth embodiment is based essentially on the first embodiment with regard to the structure and the functioning of the sensor 20. In contrast to the first embodiment, the signal processing unit 21 according to the sixth embodiment has a plurality of heating units 23 distributed over the outer surface 27 of the signal processing unit 21 facing the sensor component 1, in order to be able to actively temperature control and selectively thermally influence different regions of the sensor component 1. The heating units 23 can be controlled individually, in particular, in order to enable a temperature control of the sensor component 1 that is precisely matched to the temperature gradient G of the sensor component 1 and coordinated with one another. Furthermore, the signal processing unit 21 has a plurality of temperature sensors 24, which are arranged on the outer surface 27 of the signal processing unit 21 facing the sensor component 1 and whose sensor data can be used for regulating the heating power of the individually controllable heating units 23. This makes it possible to influence the temperature gradient G in a very precise, demand-controlled manner. The spatial temperature distribution of the sensor component 1 can be reliably estimated with the temperature sensors 24 and the heating power of the heating units 23 can be matched to this. Advantageously, the temperature sensors 24 should be spaced apart from one another in order to be able to determine the temperature gradient G. Furthermore, it is not ruled out in principle that a heating unit 23 can also be controlled without feedback of a temperature value of a temperature sensor 24, for example by determining a relative heating on the basis of the heating power used independently of an absolute temperature value.FIGS. 7 to 9 show front views of the sensors 20 according to the first, seventh and fifth embodiments, wherein the sensor components 1 and the signal processing units 21 are each shown in a state connected to one another, wherein here, by way of example, a cohesive connection means 22 is shown in order to achieve the state connected to one another.FIG. 7 shows the sensor component 1 with the support structure 2, the microsensing unit 3 having the sensing region 4 and the heat-conducting plate 7 aapplied laterally to an outer surface 6 of the support structure 2. In addition to an electrical connection, not shown in detail, the sensor component 1 is connected to the signal processing unit 21 by a connecting means 22, for example an adhesive, which is shown oversized for illustration purposes, in a materially bonded manner.According to the seventh embodiment shown in FIG. 8, the cohesive connecting means 22 between the sensor component 1 and the signal processing unit 2 has a heat-conducting structure 7 ein the form of particles which are distributed in the connecting means 22 and are thermally highly conductive, for example metal particles or graphite particles. In this way, a heat-conducting element 7 can also be provided on the outer surface 6 of the sensor component 1, wherein this embodiment of the heat-conducting element 7 can be implemented cost-effectively and easily and nevertheless has a high effectiveness along the connecting surface of the sensor component 1.In FIG. 9, the sensor 20 according to the fifth embodiment is again shown in front view, wherein the heat conducting cap 7 cis shown in section in order to clarify the structure of the heat conducting cap 7 cwith the cap opening 7 c- 1, the cap cover 7 c- 2 and the cap edge 7 c- 3.FIG. 10 shows an enlarged view of a microelectromechanical sensor component 1 for a sensor 20 designed as a pressure sensor according to an exemplary embodiment in a schematic sectional illustration. FIG. 10 shows the support structure 2 and the microsensing unit 3 arranged on the support structure 2, which according to the exemplary embodiment shown has an elastically deflectable micromembrane 14. The elastically deflectable region of the micromembranous 14 forms the sensing region 4 of the microsensing unit 3. a deflection of the micromembranous 14 can be detected, as illustrated, for example, capacitively by means of an electrode 15 and a counter electrode 16 in a capacitor arrangement, wherein other electrode arrangements or other transducers such as piezoelectric or optical detection elements can also be provided. According to the exemplary embodiment shown, the sensor component 1 has an internal cavity 13 which is formed adjacent to the micromembrane 14 of the microsensing unit 3. The cavity 13 forms a reduced-pressure countervolume and enables the deflection of the micromembrane 14 under an ambient pressure p as a measured variable M of the sensor component 1, which can be embodied accordingly as an absolute pressure sensor component. Pressure sensors, in particular pressure sensors with microelectromechanical sensor components 1, can, like other types of environmental sensors 20', be subject to a high temperature sensitivity, which can lead to measurement signal deviations even in the case of small location-dependent temperature changes. This effect can be advantageously counteracted with the proposed design of the sensor component 1 and the sensor 20.FIG. 10 furthermore shows that the sensor component 1 has a layer structure 9 arranged in a material block 8 embodied as a silicon block, for example. The mechanical and electrical microstructures of the sensor component 1 can be produced by means of the layer structure 9 and, for example, the cavity 13 can be formed. As shown in FIG. 10, a heat-conducting layer 7 dmay be arranged in the layer structure 9, which can be embodied, for example, as a metallic layer. This allows additional heat conduction in the inner structure of the sensor component 1. Furthermore, the sensor component 1 can have an integrated, electrically actuatable heating element 10, by means of which an active temperature control of the sensor component 1 is possible, for example for test or calibration purposes or for creating controlled measurement conditions. The proposed heat conducting elements 7 on the sensor component 1 can advantageously support such a temperature control by improved heat conduction on the sensor component 1.Furthermore, it is shown in FIG. 10 that the sensor component 1 can have a heat-conducting fluid 11 with a high specific thermal conductivity and a heat-insulating fluid 12 with a low specific thermal conductivity for additionally influencing a temperature gradient G on the sensor component 1. The heat-conducting fluid 11 and the heat-insulating fluid 12 can be arranged in closed chambers and, like the further heat-conducting elements 7 described, can be placed advantageously in the environment 5 of the sensor component 1 taking account of known heat sources.Furthermore, FIG. 10 shows that the sensor component 1 has a heat-conducting body 17 arranged within the carrier structure 2 and a heat-insulating body 18 arranged within the carrier structure 2. The heat-conducting body 17 can have a higher specific thermal conductivity than the support structure 2. The thermal insulation body 18 can have a lower specific thermal conductivity than the carrier structure 2. The heat conducting body 17 and / or the heat insulating body 18 can be made of a material that differs from the material of the support structure 2, for example with regard to crystallinity or composition. For example, the heat conducting body 17 and / or the heat insulating body 18 can be made of a polycrystalline silicon or of a silicon compound such as silicon dioxide or silicon nitride.With the sensors 20 and sensor components 1 described above, an effective thermal influencing of the sensor components 1 can be made possible in a simple and economically implementable manner.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedU.S. Pat. No. 11,485,630 B2

[0003]

Claims

Microelectromechanical sensor component (1) for detecting a measurement variable (M), wherein the sensor component (1) has a carrier structure (2) and a microsensing unit (3) arranged on the carrier structure (2) and having a sensing region (4), wherein the carrier structure (2) has an outer surface (6) facing an environment (5) of the sensor component (1) and wherein a heat-conducting element (7) for influencing a temperature gradient (G) of the sensor component (1) is arranged on the outer surface (6).Sensor component (1) according to Claim 1, wherein the heat-conducting element (7) comprises a heat-conducting material having a specific heat conductivity of between 200 and 500 W / mK.Sensor component (1) according to Claim 1 or 2, wherein the heat-conducting element (7) is produced from a metal or from a metal alloy.Sensor component (1) according to Claim 3, wherein the heat-conducting element (7) is produced from gold or from an aluminium-copper alloy.Sensor component (1) according to one of the preceding claims, wherein the heat-conducting element (7) is designed as a heat-conducting plate (7a).Sensor component (1) according to one of the preceding claims, wherein the heat-conducting element (7) is designed as a heat-conducting coating (7b).Sensor component (1) according to one of the preceding claims, wherein the heat-conducting element (7) is designed as a heat-conducting cap (7c).Sensor component (1) according to Claim 7, wherein the heat-conducting cap (7c) is arranged on an outer side (6') of the carrier structure (2) in such a way that the heat-conducting cap (7c) spans the sensing region (4) of the microsensing unit (3) at least in sections.Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) has a layer structure (9) arranged on a substrate or in a material block (8), and at least one layer of the layer structure (9) is formed as a heat-conducting layer (7d).Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) has at least two identical or different heat-conducting elements (7) which are designed as a heat-conducting plate (7a), as a heat-conducting coating (7b), as a heat-conducting cap (7c) or as a heat-conducting layer (7d).Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) has an electrically controllable heating element (10).Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) has a heat-conducting fluid (11) and / or a heat-insulating fluid (12).Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) has a heat-conducting body (17) arranged in particular within the carrier structure (2) and / or a heat-insulating body (18) arranged in particular within the carrier structure (2).Sensor (20) having a microelectromechanical sensor component (1) according to one of the preceding claims, wherein the sensor (20) has a signal processing unit (21), which is electrically connected to the sensor component (1), for applying and processing signals of the sensor component (1).Sensor (20) according to Claim 14, wherein the sensor component (1) is connected to the signal processing unit (21) by a cohesive connection means (22) having a heat-conducting structure (7e).The sensor (20) according to claim 14 or 15, wherein the signal processing unit (21) comprises a heating unit (23).Sensor (20) according to Claim 16, wherein the signal processing unit (21) has a temperature sensor (24) for regulating a heating power of the heating unit (23).Sensor (20) according to one of Claims 14 to 17, wherein the sensor (20) is designed as an environmental sensor (20').

Images