Micro-electromechanical sensor component, and sensor comprising a micro-electromechanical sensor component

Abstract

The invention relates to a micro-electromechanical sensor component (1) for detecting a measurement variable (M), wherein the sensor component (1) has a support structure (2) and a micro-sensing unit (3) which is provided on the support structure (2) and which comprises a sensing region (4). The support structure (2) has an outer surface (6) which faces the surroundings (5) of the sensor component (1), and the outer surface (6) is equipped with a heat-conducting element (7) in order to influence the temperature gradient (G) of the sensor component (1). The invention additionally relates to a sensor (20) comprising a micro-electromechanical sensor component (1).

Description

[0001] Description

[0002] title

[0003] Microelectromechanical sensor component and sensor with a microelectromechanical sensor component

[0004] The invention relates to a microelectromechanical sensor component and a sensor with a microelectromechanical sensor component.

[0005] State of the art

[0006] Microelectromechanical sensor components, also known as MEMS sensor components, as well as sensors with microelectromechanical sensor components are known from the state of the art.

[0007] US 11,485,630 B2 describes a micromechanical sensor with a substrate, a cap element, a seismic mass that can be deflected orthogonally to the cap element and a cavity with an internal pressure that is lower than the ambient pressure, wherein the sensor has compensation means that are designed to provide an equalization of a temperature gradient field in the cavity during operation of the micromechanical sensor.

[0008] Disclosure of the invention

[0009] According to the features of independent claim 1, a microelectromechanical sensor component for detecting a measured variable is proposed, wherein the sensor component has a support structure and a microsensing unit arranged on the support structure with a sensing region, wherein the support structure has an outer surface facing an environment 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.

[0010] A microelectromechanical sensor component according to the proposed features has the advantage of a temperature distribution across the sensor component that can be specifically influenced, for example, homogenized, allowing the temperature gradient in the sensing area of ​​the sensor component to be advantageously influenced, in particular, evened out in a simple manner. The evening out of the temperature gradient in the sensing area can be achieved indirectly by influencing the temperature gradient on the support structure of the sensor component, without, for example, the need to place suitable temperature control or compensation means directly in the sensitive sensing area or laboriously in a cavity of the microsensing unit. Furthermore, an accelerated homogenization of the temperature distribution can be achieved via the comparatively large outer surfaces of the support structure compared to the sensing area.Furthermore, it supports the avoidance of non-linear or higher-order effects that may result from an interaction of the thermal gradient with different materials of the sensor component that have different properties.

[0011] With the microelectromechanical sensor component according to the proposed features, more accurate measurement results of the measured variable are obtainable due to the specifically controllable temperature gradient of the sensor component. In particular, the thermal influence on measurement results, which can be caused, for example, by temperature-dependent nonlinearities and / or interference effects in the sensor behavior, is reduced. In particular, more accurate temperature compensation of the measurement results is enabled because location-dependent temperature changes within the sensor component and the sensing area are reduced. Furthermore, correspondingly more accurate test and calibration results can be achieved. A further advantage arises from the increased service life of the sensor component due to more uniform thermal loading, which can lead to reduced stress effects on various components of the sensor component.A microelectromechanical sensor component can be a component with mechanical and electrical microstructures, for example, with microstructures with dimensions in the micrometer and / or nanometer range. The sensor component can be produced, for example, using semiconductor technology, in particular silicon-based. In particular, the mechanical and electrical microstructures can consist of polycrystalline and / or doped silicon and / or silicon compounds. Due to their dimensions, microelectromechanical sensor components can be used in miniaturized sensor modules and are suitable, for example, for use in mobile devices.

[0012] A measured variable that can be detected by the microelectromechanical sensor component can, for example, be a physical measured variable, in particular an environmental condition of the sensor component, such as pressure, humidity, or temperature. Other measurable measured variables can, for example, be kinematic measured variables, such as acceleration. The measured variable can be detected through a physical interaction between the microsensing unit and the environment of the sensor component.

[0013] A support structure of the sensor component can form a mechanical base or a mechanical frame structure of the microsensing unit. The support structure can be configured to support the microsensing unit or to hold it in space. Furthermore, the support structure can form mechanical components of the microsensing unit, for example, boundary surfaces of a cavity of the microsensing unit. The support structure further enables mechanical support and spacing of the microsensing unit from adjacent components, for example, from a sensor housing or a signal processing unit of a sensor having the sensor component. In addition, the support structure provides a protective function for the microsensing unit against external influences. The support structure can additionally form a support 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 internal cavity, which can in particular be formed adjacent to a micromembrane of the microsensing unit. According to one possible design of the microelectromechanical sensor component, the support structure can be made of silicon, in particular monocrystalline silicon.

[0014] A microsensing unit of the sensor component can be or comprise a microstructural measuring device, for example, an elastically deflectable micromembrane or a displaceable micro-flywheel. 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 sensitive to the measured 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 contact with the environment 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.

[0015] An environment of the sensor component can be a space surrounding the sensor component. For example, a space delimited by a sensor housing of a sensor accommodating the sensor component can already be considered the environment of the sensor component. In the case of an exposed sensor component, the environment of the sensor component can be formed by the free atmosphere.

[0016] An outer surface of the support structure facing the environment of the sensor component can be an outer surface of the support structure. Depending on the specific design of the sensor component and, if applicable, an existing arrangement of the sensor component in a higher-level component system, surface sections of the outer surface can be exposed or covered by an adjacent component. For example, the sensor component can be connected to a signal processing unit of a sensor via part of its outer surface, 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 exposed parts of the outer surface. Depending on the geometric shape of the sensor component, the outer surface can be formed by multiple outer sides.For example, in a cuboid-shaped design of the sensor component, a top side, a bottom side, and side surfaces extending between the top side and the bottom side can form the outer surface of the sensor component. The microsensing unit of the sensor component can be arranged, for example, on a top side of the support structure or, for example, in the case of a microsensing unit embedded in a recess in the support structure, closer to a top side than to a bottom side of the support structure. The support structure or its outer surface can have a defined depth and form a solid body.

[0017] A heat-conducting element can be a particularly passive structural element with a defined thermal conductivity, which can in particular be higher than the thermal conductivity of the support structure. In principle, it is not excluded to design the heat-conducting element as, for example, an energizable active structural element, in order to enable targeted local temperature control of the support structure using the heat-conducting element, if required.

[0018] A temperature gradient, also known as a thermal gradient, corresponds to a directed physical quantity that describes the spatial dependence of temperature. A temperature gradient can therefore be understood as a spatial change in temperature. A temperature gradient can be described, for example, in Kelvin per meter. In this case, the temperature gradient can be viewed simply as a temperature drop within the sensor component from a warmer component area to a colder component area. The temperature gradient of the sensor component can be influenced by the heat-conducting element, in particular, to achieve a more homogeneous temperature distribution. Accordingly, the use of the heat-conducting element is intended, in particular, to equalize or reduce the temperature drop across the sensor component.

[0019] The heat-conducting element can be arranged on the outer surface of the support structure 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, at least 20%, at least 40%, or at least 80% of the outer side. According to advantageous embodiments, full-surface coverage of at least one outer side of the outer surface can also be provided. Through a clever, individually coordinated design of the heat-conducting element with regard to its shape, thermal conductivity, and positioning on the support structure, compensation for known heat sources in the vicinity of the sensor component or in predefined thermal situations can be optimized.

[0020] According to one embodiment, the heat-conducting element can comprise a heat-conducting material with a specific thermal conductivity between 200 and 500 W / mK. In particular, the heat-conducting element can comprise a heat-conducting material with a specific thermal conductivity between 250 and 450 W / mK, in particular between 300 and 400 W / mK. Specific thermal conductivity, also called thermal conductivity number or thermal conductivity coefficient, can be understood as a material property that determines the heat flow through a material due to thermal conduction. Compared to the thermal conductivity ranges mentioned, silicon, for example, which is a frequently used material for support structures of microelectromechanical sensor components, has a thermal conductivity of approximately 150 W / mK and thus a lower thermal conductivity than the intended heat-conducting element.A specific thermal conductivity of the heat-conducting element in one of the mentioned value ranges enables an effective influence of the temperature gradient of the microelectromechanical sensor component across its outer surface and can be implemented economically using readily available materials.

[0021] According to one embodiment, the heat-conducting element can be made of a metal or a metal alloy. Metals and metal alloys are readily available materials with favorable thermal conduction properties. A heat-conducting element made of a metal or a metal alloy can be easily produced and, for example, either created using a conventional metal processing method and applied to the support structure or created directly on the support structure using a MEMS manufacturing method. According to a further development of the above-described embodiment, the heat-conducting element can be made of gold or an aluminum-copper alloy. Gold and an aluminum-copper alloy represent a metal and a metal alloy with very good thermal conduction properties, are easy to process, and also exhibit high thermal and chemical resistance.Gold and aluminum-copper alloys can also be connected to other structural units on the sensor component through process technology or during molding, for example with connection pads for bond wires, markings, signal lines or other sensor elements that can, for example, enable accompanying temperature measurement on the sensor component.

[0022] According to one embodiment, the heat-conducting element can be designed as a heat-conducting plate. A heat-conducting plate represents a robust and easily manufactured heat-conducting element that also increases the mechanical stability of the support structure. A heat-conducting plate can be a flat, continuous structural element that is placed on the outer surface of the support structure, in particular is mechanically or materially connected to it. The heat-conducting plate can be a substantially rigid mechanical structural element. The heat-conducting plate can rest flatly on the outer surface. The heat-conducting plate can form a mechanical cover for the support structure. According to one possible embodiment, the heat-conducting plate can be designed as a thin metal sheet.The shape and dimensions of the heat-conducting plate can advantageously correspond to the shape and dimensions 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 essentially congruently on one another. According to one possible embodiment, the heat-conducting plate can have an intermediate medium such as a highly viscous thermal paste or an adhesive layer. If the heat-conducting plate is arranged on an outer side containing the microsensing unit, for example on the upper side, the heat-conducting plate can have a sensing opening that is essentially congruent with the sensing region of the microsensing unit, so 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 thermally conductive coating can be a thermally conductive element in the form of a material-bonded coating on the outer surface of the support structure. The thermally conductive coating can be designed, for example, as a continuous metallic coating or as a coating with a carrier substance and metallic particles distributed therein. A thermally conductive coating can advantageously be applied to the sensor component as part of a sub-process of a MEMS manufacturing process during its production. Depending on the outer surface of the support structure to be coated, it is conceivable for the sensor component to be placed in different orientations at the processing site, 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 thermally conductive coating on the support structure can be applied very thinly, resulting in material savings and an economic advantage compared to rigid structural elements used as thermally conductive elements. Furthermore, it is conceivable to combine a coating process for applying the thermally conductive coating to the support structure with additional process steps such as plasma treatments, which can advantageously influence the surface or surface properties of the sensor component.

[0023] 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 from the outer surface. The cap cover can, for example, run parallel to the outer surface and differ in its spacing from a heat-conducting plate that is in surface contact with the outer surface. The cap cover and the cap edge of the heat-conducting cap can enclose an internal volume with the outer surface. With a heat-conducting element designed as a heat-conducting cap, improved heat distribution on the sensor component can be achieved, since heat from a warmer component area can be quickly distributed across the entire sensor component via the heat-conducting cap. Furthermore, heat convection and radiation on the sensor component can be reduced, thereby achieving a beneficial effect on the temperature gradient.

[0024] According to a further development of the above-described embodiment, the heat-conducting cap can be arranged on an outer side of the support structure such that the heat-conducting cap spans the sensing region of the micro-sensing unit at least in sections. In other words, the heat-conducting cap can cover the sensing region in a bridge-like manner. Spanning at least in sections implies that the heat-conducting cap does not have to cover the sensing region across 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 several smaller, decentralized cap openings. Such cap openings can, for example, form a pressure access structure of the heat-conducting cap in order to enable or improve interaction of the sensing region with the environment.By using a heat-conducting cap that spans at least part of the sensing area, the temperature gradient can be advantageously influenced, particularly homogenized, close to the sensing area without mechanically or electrically impairing the sensing area. This also increases mechanical protection of the sensing area and reduces the risk of contamination from particles entering the sensing area. Furthermore, the heat-conducting cap contributes to reducing convection in the sensing area, thus promoting a more uniform temperature gradient.

[0025] 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 designed as a thermally conductive layer. The substrate can be, for example, a silicon wafer. The material block can be, for example, a silicon block. The layer structure can be produced to manufacture 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. For example, a continuous metallic layer can be integrated into the layer structure as a thermally conductive layer. This can enable additional, improved heat conduction not only on the outer surface of the carrier component, but also via the internal structure of the sensor component.According to one possible embodiment, the thermally conductive layer can be present in addition to an existing heating element and can be distinguished from it, for example, by spatial spacing and / or by the thermally conductive layer not having an electrical connection structure. By applying a thermally conductive layer to the substrate or to a layer of the layered structure as part of a MEMS manufacturing process for the sensor component, or by introducing a thermally conductive layer into the material block as part of a MEMS manufacturing process for the sensor component, the creation of the thermally conductive layer can be easily integrated into the manufacturing process of the sensor component.

[0026] 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, a heat-conducting coating, a heat-conducting cap, or a heat-conducting layer. The terms "identical" and "different" refer to the aforementioned possible embodiments of the heat-conducting element. In other words, it is conceivable to combine identical and / or different embodiments of the heat-conducting elements on the sensor component in a meaningful way in order to achieve particularly rapid and efficient influencing, in particular homogenization, of the temperature gradient across the sensor component.

[0027] 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 actively controlling the temperature of regions of the sensor component, in particular the sensing region. The electrically controllable heating element can be used for actively controlling the temperature of component regions of the sensor component, in particular the sensing region, for example, to ensure defined measurement conditions or to enable measurements of certain temperature-dependent measurands such as humidity. The electrically controllable heating element can also be used for test and calibration functions in order to achieve particularly precise test and calibration results on the sensor component.Especially for sensor components with an integrated heating function, whose heating element can introduce thermal energy into the sensor component in a spatially limited manner, the heat-conducting element according to the proposed features can advantageously contribute to the homogenization of a temperature gradient across the sensor component.

[0028] According to one embodiment, the sensor component can comprise a thermally conductive fluid and / or a thermally insulating fluid. A thermally conductive fluid can be a liquid, a gas, or a liquid-gas mixture with a high specific thermal conductivity, which can in particular be higher than the specific thermal conductivity of the support structure. A thermally insulating 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 support structure. The thermally conductive fluid and / or the thermally insulating fluid can, for example, each be arranged in a closed chamber in the sensor component and serve there locally for targeted heat conduction or thermal insulation. The respective position of the chambers can be selected, for example, depending on known heat sources or thermal effects in the environment of the sensor component.To introduce the thermally conductive fluid and / or the thermally insulating fluid into such a chamber, an open chamber can be created in the manufacturing process of the sensor component, the chamber can be filled with the thermally conductive fluid or thermally insulating fluid, and then a liquid-tight or gas-tight closure of the chamber can be created.

[0029] Alternatively or in addition to a chamber accommodating the thermally conductive or thermally insulating fluid, a sponge body can be formed in the sensor component and provided for the concentrated absorption of the thermally conductive or thermally insulating fluid. A thermally conductive and / or thermally insulating fluid provides an additional option for the targeted influencing of the temperature gradient across the sensor component.

[0030] According to one embodiment, the sensor component can have a heat-conducting body, in particular arranged within the support structure, and / or a heat-insulating body, in particular arranged within the support structure. The heat-conducting body and / or the heat-insulating body can in particular comprise a semiconductor material, in particular silicon. The semiconductor material can in particular differ from the material of the support structure, for example with regard to crystallinity or composition. If the support structure is made of monocrystalline silicon, for example, the heat-conducting body and / or the heat-insulating body can be made of polycrystalline silicon or of a silicon compound such as silicon dioxide or silicon nitride. 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 support structure. A thermally conductive body and / or thermal insulation body can further improve the influence of the thermal gradient of the sensor component, for example, to compensate for the influence of heat sources on the sensor component.

[0031] The invention also relates to a sensor with a microelectromechanical sensor component according to one of the above-described features, wherein the sensor has a signal processing unit electrically connected to the sensor component for applying and processing signals from the sensor component. The proposed sensor also achieves the above-described advantages of a specifically controllable, for example, homogenizable temperature distribution across the sensor component, as well as resulting more precise measurement, test, and calibration results, as well as an increased service life of the sensor component. The sensor's signal processing unit provides further possibilities for enhancing the described positive effects, as 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.

[0032] A signal processing unit can be understood as a control circuit, which can be implemented in particular as an integrated circuit, for example, as an ASIC (application-specific integrated circuit). The signal processing unit can be used to control the sensor component and receive and optionally also evaluate sensor signals from 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 bond wiring.

[0033] According to one embodiment, the sensor component can be connected to the signal processing unit by a material-to-material connecting means having a heat-conducting structure. The material-to-material connecting 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 material-to-material connecting means having the heat-conducting structure can have a thermal conductivity that is higher than the thermal conductivity of the support structure of the sensor component.In particular, it can be provided that the sensor component is integrally connected to the signal processing unit 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 can be provided, as opposed to point-like, for example, soldered connection points. By connecting the sensor component to the signal processing unit using a material-to-material connecting means having a heat-conducting structure, a simple and economical way of improving temperature distribution across the outer surface of the sensor component can be provided. By connecting the sensor component to the signal processing unit, a mechanical fixation of the sensor component, which would otherwise potentially be free-floating, can be enabled.The connecting means fulfills several functions with regard to the material-to-material connection of the components to one another and to improved heat conduction on the outer surface of the sensor component. Furthermore, the material-to-material connecting means can serve to decouple external stresses. According to one embodiment, the signal processing unit can have a heating unit. This can provide an additional option 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 controlling the temperature of a component region of the sensor component connected to the signal processing unit. The heating unit can in particular be arranged on an outer surface of the signal processing unit facing the sensor component.When the sensor component is connected to the signal processing unit by means of a material-to-material connection means, the heating unit can be in thermally conductive contact with the outer surface of the sensor component opposite the heating unit via the connection means. Advantageously, the connection means can have a thermally conductive structure as described above, so that the thermal energy transmitted by the heating unit can be optimally distributed across the material-to-material connection area. According to one possible embodiment, several heating units distributed across the outer surface of the signal processing unit facing the sensor component can be arranged on the signal processing unit in order to actively control the temperature of different areas of the sensor component and thus contribute to a targeted influence on the temperature gradient in several component areas of the sensor component.The multiple heating units can, in particular, be individually controllable to enable temperature control of the sensor component that is precisely matched to the temperature gradient of the sensor component and coordinated with each other. According to a further embodiment, the heating unit can be arranged at a distance from an electrical connection structure, for example a wire bond connection between the signal processing unit and the sensor component. This allows a thermal circuit to be formed across the selected distance through the sensor component between the heating unit and the connection structure, which, due to its typically metallic structure, is also advantageously thermally conductive. The thermal circuit can support a homogenization of the temperature gradient through the sensor component.

[0034] According to one embodiment, the signal processing unit can have a temperature sensor for regulating the heating power of the heating unit. This enables very precise, active influencing of the temperature gradient. The temperature sensor can detect a local temperature value and infer a temperature gradient present in the sensor component, which can be finely influenced using the controllable heating power and monitored via the temperature sensor. According to one possible embodiment, several temperature sensors spatially distributed across 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.This makes it possible, particularly in combination with several heating units, to enable individual local temperature control of the sensor component and accordingly to actively influence the homogenization of the temperature gradient, particularly in the form of a control loop that uses temperature signals from the temperature sensors to control the heating units.

[0035] According to one embodiment, the sensor can be designed as an environmental sensor. An environmental sensor can be configured to measure environmental conditions. According to one possible configuration, the sensor can be designed as a pressure sensor. Environmental sensors, in particular environmental sensors with microelectromechanical sensor components, often exhibit high temperature sensitivity. In particular, even small, location-dependent temperature changes can result in thermally induced deviations in the measurement signal. Against this background, the proposed thermal conduction concept for influencing the temperature gradient at the sensor component of the sensor can be used effectively and with significant advantages in an environmental sensor.

[0036] In general, in the context of this application, the words "a / an," unless expressly defined otherwise, are not to be understood as a number, but as an indefinite article with the literal meaning of "at least one / an." The invention permits various embodiments and is explained in more detail below using exemplary embodiments with the accompanying drawings. They show, in a simplified schematic manner:

[0037] Fig. 1 - a sensor with a microelectromechanical sensor component and a signal processing unit according to a first embodiment in a perspective front view;

[0038] Fig. 2 - a sensor with a microelectromechanical sensor component and a signal processing unit according to a second embodiment in a perspective front view;

[0039] Fig. 3 - a sensor with a microelectromechanical sensor component and a signal processing unit according to a third embodiment in a perspective front view;

[0040] Fig. 4 - a sensor with a microelectromechanical sensor component and a signal processing unit according to a fourth embodiment in a perspective front view;

[0041] Fig. 5 - a sensor with a microelectromechanical sensor component and a signal processing unit according to a fifth embodiment in a perspective front view;

[0042] Fig. 6 - a sensor with a microelectromechanical sensor component and a signal processing unit according to a sixth embodiment in a perspective front view;

[0043] Fig. 7 - the sensor according to the first embodiment with the sensor component and the signal processing unit in a connected state in a front view;

[0044] Fig. 8 - a sensor according to a seventh embodiment with the sensor component and the signal processing unit in a connected state in a front view;

[0045] Fig. 9 - the sensor according to the fifth embodiment with the sensor component and the signal processing unit in a connected state in a front view; and

[0046] Fig. 10 - 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, based on schematic principle sketches, sensors 20 with microelectromechanical sensor components 1 and signal processing units 21 in various views. To facilitate understanding and improve clarity, the sensor components 1 and the signal processing units 21 are spaced apart from one another in Figs. 1 to 6 and are shown in all figures with peripheral structures such as bond wires, substrate, or the sensor package omitted.

[0047] Fig. 1 schematically shows a sensor 20 with a microelectromechanical sensor component 1 and a signal processing unit 21 according to a first embodiment. The sensor component 1 serves to detect a measured variable M, as shown by way of example in Fig. 10 as ambient pressure p. According to the exemplary embodiments shown in Figures 1 to 10, the sensor 20 is designed as an ambient sensor 20', and the sensor component 1 is configured to detect a measured variable M of an environment 5 of the sensor component 1.

[0048] The sensor component 1 has a support structure 2 and a microsensing unit 3 arranged on the support structure 2 with 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 support structure 2 forms a support for electrical connection structures of the sensor component 1 (not shown in detail), via which the microsensing unit 3 is or can be electrically connected to the signal processing unit 21. The support 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, for example, be designed as an elastically deflectable micromembrane 14, as shown in Fig. 10.

[0049] The support structure 2 has an outer surface 6 facing the environment 5 of the sensor component 1, which forms an outer surface of the support structure 2. According to the exemplary embodiment shown, the support structure 2 is a cuboid-shaped solid. The outer surface 6 of the support structure 2 is therefore divided into several outer sides 6', which form an upper side 6a, a lower side 6b, and side surfaces 6c of the support structure 2 that connect 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 6a of the support structure 2.

[0050] 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 support structure 2. According to the exemplary embodiment shown in Fig. 1, the heat-conducting element 7 is arranged on an exposed side surface 6c of the support structure 2 and covers this essentially over its entire surface and essentially congruently. According to the exemplary embodiment shown in Fig. 1, the heat-conducting element 7 is designed as a heat-conducting plate 7a. The heat-conducting plate 7a forms a flat mechanical structural element which, according to the exemplary embodiment, is applied to a side surface 6c of the support structure 2 and rests flatly on the outer surface 6. The heat-conducting plate 7a forms a cover of the support structure 2 on its side surface 6c. According to one possible embodiment, the heat-conducting plate 7a can have a highly viscous thermal paste or an adhesive layer for attachment.

[0051] 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 support structure 2. For example, the heat-conducting element 7 can have a specific thermal conductivity between 200 and 500 W / mK. For this purpose, the heat-conducting element 7 can be made of a metal, for example, gold, or of a metal alloy, for example, an aluminum-copper alloy. According to alternative embodiments, the heat-conducting element 7 can also be designed as an energizable active structural element in order to be able to implement targeted active temperature control.

[0052] By means of the heat-conducting element 7, a temperature distribution can be specifically influenced, for example, homogenized, across the sensor component 1. This also makes it possible to even out the temperature profile in the temperature-sensitive sensing area 4, enabling more accurate measurement results with the micro-sensing unit 3. The heat-conducting element 7 arranged on the outer surface 6 of the support structure 2 enables rapid homogenization and keeps the sensing area 4 free of temperature control and compensation media. Furthermore, non-linear and higher-order effects due to interactions of the temperature gradient G with various materials of the sensor component 1 are avoided. By reducing location-dependent temperature changes on the sensor component 1, more accurate temperature compensation can be achieved, and more precise test and calibration results can be obtained.The resulting more uniform thermal load on the sensor component 1 with reduced stress effects can increase the durability and service life of the sensor component 1.

[0053] In addition to the sensor component 1, the sensor 20 has a signal processing unit 21. 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, and is configured to apply and process signals from 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 connected to it mechanically or by a material bond. According to a non-limiting example to illustrate sensor dimensions, the signal processing unit 21 can have a height of approximately 160 pm, the sensor component can have a height of approximately 220 pm, and a layer height of a material bonding means 22 can be approximately 75 pm.The signal processing unit 21 has a heating unit 23, which provides a simple possibility for a targeted, active influence on the temperature gradient G on the sensor component 1. The heating unit 23 can be arranged, as shown, on an outer surface 27 of the signal processing unit 21 facing the sensor component 1.

[0054] 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 essentially based on the first embodiment with regard to the structure and mode of operation of the sensor 20. In contrast to the first embodiment, a heat-conducting element 7, which is designed as a heat-conducting coating 7b, is arranged on the side surfaces 6c of the carrier structure 2. The heat-conducting coating 7b can be a material-to-material coating on the outer surface 6 of the carrier structure 2. Depending on the embodiment, the heat-conducting coating 7b can be designed, for example, as a continuous metallic coating or as a coating with a carrier substance and metallic particles distributed therein.The thermally conductive coating 7b can advantageously have been applied to the carrier structure 2 as part of a MEMS manufacturing process during the production of the sensor component 1, wherein the coating could, for example, optionally also be used to plasma-treat the outer surface 6 of the carrier structure 2 in order to optimize the surface properties of the sensor component 1.

[0055] 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 essentially based on the first embodiment with regard to the structure and operation of the sensor 20. In contrast to the first embodiment, the heat-conducting element 7, designed as a heat-conducting plate 7a, is not arranged on a side surface 6c, but on the top side 6a of the support structure. This also allows a favorable influence on the temperature gradient G to be achieved, whereby this takes place close to the microsensing unit 3, but without impairing it through compensating structures arranged directly in the sensing area 4.Due to its arrangement on the upper side 6a of the support structure 2, which has the microsensing unit 3, the heat-conducting plate 7a has a sensing opening 7a-1 congruent with the sensing area 4 of the microsensing unit 3, so that the sensing area 4 is not covered or impaired by the heat-conducting plate 7a.

[0056] Fig. 4 shows, using a fourth embodiment of the sensor 20, that, for example, the second and third embodiments can be meaningfully combined with one another according to the features described above. By means of a heat-conducting coating 7b arranged on the side surfaces 6b and a heat-conducting plate 7a arranged on the top side 6a, the advantages of different heat-conducting elements 7 distributed over the outer surface 6 of the support structure 2 can be combined and a faster homogenization of a temperature gradient G can be achieved. In principle, combinations of identical heat-conducting elements 7 are also feasible, for example heat-conducting coatings 7b on the top side 6a and on the side surfaces 6c or heat-conducting plates 7a on the top side 6a and on the side surfaces 6c. Furthermore, the combinations can also include other embodiments of the heat-conducting element 7, which are described in more detail below.

[0057] 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 functioning of the sensor 20. In contrast to the first embodiment, the heat-conducting element 7 is designed as a heat-conducting cap 7c. The heat-conducting cap 7c is arranged on an outer side 6', here on the upper side 6a of the support structure 2, such that the heat-conducting cap 7c spans the sensing region 4 of the micro-sensing unit 3 at least in sections. The heat-conducting cap 7c has a cap opening 7c-1, via which an interaction between the sensing region 4 and the environment 5 of the sensor component 1 is enabled. As can be seen, for example, when considering Fig. 5 in conjunction with the front view in Fig.As can be seen in Fig. 9, the heat-conducting cap 7c has a cap cover 7c-2 and a circumferential cap edge 7c-3, wherein the cap cover 7c-2 runs at a distance from the outer surface 6 by the cap edge 7c-3 and therefore differs from a heat-conducting plate 7a that is in surface contact with the outer surface 6. As can be seen in Fig. 9, the cap cover 7c-2, the cap edge 7c-3 and the outer surface 6 enclose an internal volume. With a heat-conducting cap 7c, heat can be distributed very quickly and at the same time gently across the sensor component 1, in particular across the sensing area 4. At the same time, heat convection and heat radiation at the sensor component 1 are reduced, thereby achieving a beneficial effect on the temperature gradient G. In addition, mechanical protection of the sensing area 4 is increased and the risk of contamination due to particles entering the sensing area 4 is reduced.

[0058] Furthermore, the sensor 20 according to the fifth embodiment illustrates that the heating unit 23 of the signal processing unit 21 is arranged at a distance 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. A selected distance A between the heating unit 23 and the electrical connection structure 25 can thereby form a heat circuit 26 through the sensor component 1 between the heating unit 23 and the electrical connection structure 25, thereby additionally supporting the homogenization of the temperature gradient G by the sensor component 1.

[0059] 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 essentially based on the first embodiment with regard to the structure and 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 specifically thermally influence different areas of the sensor component 1. The heating units 23 can be controlled individually in particular in order to enable 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 to regulate the heating output of the individually controllable heating units 23. This enables very precise, demand-controlled influencing of the temperature gradient G. The spatial temperature distribution of the sensor component 1 can be reliably estimated using the temperature sensors 24, and the heating output of the heating units 23 can be adjusted accordingly. The temperature sensors 24 should advantageously be spaced apart from one another in order to be able to determine the temperature gradient G.Furthermore, it is fundamentally not excluded to control a heating unit 23 without feedback of a temperature value from a temperature sensor 24, for example by determining a relative heating based on the applied heating power independently of an absolute temperature value.

[0060] 7 to 9 show front views of the sensors 20 according to the first, a seventh and the fifth embodiment, wherein the sensor components 1 and the signal processing units 21 are each shown in a connected state, wherein here, by way of example, a material-to-material connecting means 22 is shown in order to achieve the connected state.

[0061] Fig. 7 shows the sensor component 1 with the support structure 2, the microsensing unit 3 having the sensing area 4, and the heat-conducting plate 7a applied 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 integrally connected to the signal processing unit 21 via a connecting means 22, for example, an adhesive, which is shown oversized for illustrative purposes.

[0062] According to the seventh embodiment shown in Fig. 8, the material-to-material connecting means 22 between the sensor component 1 and the signal processing unit 2 has a heat-conducting structure 7e in the form of highly thermally conductive particles, for example, metal particles or graphite particles, distributed in the connecting means 22. 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 is cost-effective and easy to implement, while still being highly effective along the connecting surface of the sensor component 1. Fig. 9 shows the sensor 20 according to the fifth embodiment again in a front view, with the heat-conducting cap 7c shown in section to illustrate the structure of the heat-conducting cap 7c with the cap opening 7c-1, the cap cover 7c-2, and the cap edge 7c-3.

[0063] 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 view. 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 micromembrane 14 forms the sensing region 4 of the microsensing unit 3. A deflection of the micromembrane 14 can, as shown, be detected capacitively, for example, by means of an electrode 15 and a counterelectrode 16 in a capacitor arrangement. Other electrode arrangements or other transducers, such as piezoelectric or optical sensing elements, can also be provided.According to the illustrated embodiment, 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 pressure-reduced counter-volume and enables the deflection of the micromembrane 14 under an ambient pressure p as the measured variable M of the sensor component 1, which can accordingly be designed as an absolute pressure sensor component. Pressure sensors, in particular pressure sensors with microelectromechanical sensor components 1, like other types of ambient sensors 20', can be subject to high temperature sensitivity, which can lead to measurement signal deviations even with small location-dependent temperature changes. This effect can be advantageously counteracted with the proposed design of the sensor component 1 and the sensor 20.

[0064] Fig. 10 further shows that the sensor component 1 has a layer structure 9 arranged in a material block 8, for example, designed as a silicon block. The mechanical and electrical microstructures of the sensor component 1 can be created 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 7d can be arranged in the layer structure 9, which can be designed, for example, as a metallic layer. This can enable additional heat conduction in the internal structure of the sensor component 1. Furthermore, the sensor component 1 can have an integrated, electrically controllable heating element 10, by means of which active temperature control of the sensor component 1 is possible, for example for testing or calibration purposes or to create controlled measuring conditions.The proposed heat conducting elements 7 on the sensor component 1 can advantageously support such temperature control by improved heat conduction on the sensor component 1.

[0065] Furthermore, Fig. 10 shows that the sensor component 1 is a thermally conductive fluid

[0066] 11 with a high specific thermal conductivity and a thermal insulation fluid

[0067] 12 with a low specific thermal conductivity for additionally influencing a temperature gradient G on the sensor component 1. The thermally conductive fluid 11 and the thermally insulating fluid 12 can be arranged in closed chambers and, like the other described thermally conductive elements 7, can advantageously be placed in the environment 5 of the sensor component 1, taking into account known heat sources.

[0068] Furthermore, Fig. 10 shows that the sensor component 1 has a heat-conducting body 17 arranged within the support structure 2 and a heat-insulating body 18 arranged within the support structure 2. The heat-conducting body 17 can have a higher specific thermal conductivity than the support structure 2. The heat-insulating body 18 can have a lower specific thermal conductivity than the support 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 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 influence on the sensor components 1 can be achieved in a simple and economically feasible manner.

Claims

Claims 1. 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).

2. Sensor component (1) according to claim 1, wherein the heat-conducting element (7) comprises a heat-conducting material with a specific thermal conductivity between 200 and 500 W / mK.

3. Sensor component (1) according to claim 1 or 2, wherein the heat-conducting element (7) is made of a metal or a metal alloy.

4. Sensor component (1) according to claim 3, wherein the heat-conducting element (7) is made of gold or of an aluminum-copper alloy.

5. Sensor component (1) according to one of the preceding claims, wherein the heat-conducting element (7) is designed as a heat-conducting plate (7a).

6. Sensor component (1) according to one of the preceding claims, wherein the heat-conducting element (7) is designed as a heat-conducting coating (7b).

7. Sensor component (1) according to one of the preceding claims, wherein the heat-conducting element (7) is designed as a heat-conducting cap (7c).

8. Sensor component (1) according to claim 7, wherein the heat-conducting cap (7c) is arranged on an outer side (6') of the support structure (2) in such a way that the Heat-conducting cap (7c) spans the sensing area (4) of the micro-sensing unit (3) at least in sections.

9. 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 designed as a heat-conducting layer (7d).

10. 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).

11. Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) has an electrically controllable heating element (10).

12. Sensor component (1) according to one of the preceding claims, wherein the sensor component (1) comprises a thermally conductive fluid (11) and / or a thermally insulating fluid (12).

13. 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 support structure (2) and / or a heat-insulating body (18) arranged in particular within the support structure (2).

14. Sensor (20) with a microelectromechanical sensor component (1) according to one of the preceding claims, wherein the sensor (20) has a signal processing unit (21) electrically connected to the sensor component (1) for applying and processing signals from the sensor component (1).

15. Sensor (20) according to claim 14, wherein the sensor component (1) is formed by a material-fit joint having a heat-conducting structure (7e). Connecting means (22) is connected to the signal processing unit (21).

16. Sensor (20) according to claim 14 or 15, wherein the signal processing unit (21) comprises a heating unit (23).

17. Sensor (20) according to claim 16, wherein the signal processing unit (21) has a temperature sensor (24) for controlling a heating power of the heating unit (23).

18. Sensor (20) according to one of claims 14 to 17, wherein the sensor (20) is designed as an environmental sensor (20').

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