Method for detecting inclusions in a micromechanical sensor filling medium and sensor system

Abstract

A method 100, 200 for detecting inclusions 340 in a filling medium 330 of a micromechanical sensor 305 and a sensor system 300 comprising the micromechanical sensor are presented. The method comprises the steps of providing 105, 205 a micromechanical sensor 305 having a sensor element 315 arranged in a housing 325 comprising a filling medium 330, which surrounds the sensor element and / or an adjoining heating structure 310; feeding thermal energy Q by means of the heating structure during a heating time t, wherein the filling medium acts as a thermal conductor for the sensor element in a first operating mode 301, and so detecting inclusions 340 in the filling medium: detecting a warming T of the micromechanical sensor based on said thermal energy, wherein the inclusions cause a change in the thermal capacity of the micromechanical sensor relative to the condition without inclusions in a second operating mode 302 of the filling medium.

Description

Technical Field

[0001] This invention relates to a method for detecting inclusions in a filling medium of a micromechanical sensor. The invention also relates to a sensor system including such a micromechanical sensor. Background Technology

[0002] Micromechanical sensors having a filling medium and a heating structure for heating are known from the published document DE 10 2005 029 841 A1, as well as a method for controlling and / or adjusting the heating power of the heating structure. Summary of the Invention

[0003] The objective of this invention is to describe an improved method for detecting inclusions in a filling medium of a micromechanical sensor and an optimized sensor system including such a micromechanical sensor.

[0004] This task is accomplished by the method according to the invention for detecting inclusions in the filling medium of a micromechanical sensor and the sensor system according to the invention. Other advantageous embodiments of the invention are described below.

[0005] A method for detecting inclusions in the filling medium of a micromechanical sensor and a sensor system are proposed. The sensor system includes a micromechanical sensor for detecting a measurable parameter, at least one electronic component for detecting heating of the micromechanical sensor, and an adjacent heating structure. The micromechanical sensor includes a sensor element and analysis processing circuitry for signal processing, and is particularly configured as a pressure sensor. The sensor element and analysis processing circuitry are arranged in a housing, wherein the housing includes a filling medium surrounding the sensor element and / or the analysis processing circuitry and / or the adjacent heating structure, and is particularly configured as a protective gel. The at least one electronic component may also be arranged in the housing. The heating structure is designed to feed thermal energy during a heating time, wherein the filling medium functions as a thermal conductor for the sensor element in a first operating mode. The analysis processing circuitry is designed to identify inclusions, particularly air inclusions, in the filling medium by detecting the heating of the micromechanical sensor based on the thermal energy fed during the heating time using at least one electronic component. In a second operating mode of the filling medium, the inclusion causes a change in the thermal capacity of the micromechanical sensor relative to the absence of inclusions.

[0006] The proposed method and sensor system enable cost-effective and simple implementations, particularly for cases where heating structures are already integrated into the micromechanical sensor, structures that have not yet been used to detect inclusions in the filling medium of the micromechanical sensor. Due to the flexibility in mounting the heating structure on the micromechanical sensor or within its housing, subsequent modifications or expansions of the heating structure can be achieved without significant overhead. The proposed method, along with the sensor system, can be used during the manufacturing process of the micromechanical sensor (e.g., in end-of-line control during production) and can be used to detect inclusions in the filling medium. Therefore, this invention provides an advantageous alternative to costly and time-consuming screening methods, such as those performed using X-ray analysis or acoustic scanning microscopy. Furthermore, the method can also be used to identify potential performance deviations when using micromechanical sensors in various customer-specific end devices. Without the proposed invention, this inspection is either impossible or extremely difficult to achieve.

[0007] Here, the proposed invention advantageously utilizes the fact that the materials of the analytical processing circuit, the sensor element, the filling medium, and other components that may be arranged within the micromechanical sensor housing each have a defined heat capacity when heated by means of a heating structure. Their sum, according to weight proportions, constitutes, for example, the heat capacity of the micromechanical sensor. With inclusions, such as air inclusions, in the filling medium, preferably configured as a protective gel, the heat capacity of the aforementioned components changes when heated by means of a heating structure. The change in heat capacity, or the deviation between the reference temperature and the actual temperature of the micromechanical sensor, can then be used specifically to determine the presence of inclusions. The micromechanical sensor can advantageously be constructed in the form of a pressure sensor, wherein the sensor element then corresponds to a pressure-sensitive membrane and the measured parameter to be sensed corresponds to the external pressure acting on the membrane. The membrane can be vacuum-sealed to close the cavity.

[0008] In another embodiment, the identification of inclusions in the filling medium by the analysis processing circuit includes comparing the heating of the micromechanical sensor with a reference heating detected by another sensor based on the heat energy supplied during the heating time. Furthermore, the identification of inclusions in the filling medium by the analysis processing circuit includes determining the presence of inclusions if a deviation occurs between the heating of the micromechanical sensor and the reference heating. Thus, advantageously, no additional components are required, because the analysis processing circuit, for example, can be implemented as an ASIC to take over signal processing and can identify such inclusions in the filling medium according to the aforementioned criteria. In particular, this improves the reliability of the proposed micromechanical sensor, or facilitates faster "error finding" in the case of sensors damaged due to inclusions. Here, the comparability of the heating of the micromechanical sensor and the reference heating can be obtained, for example, by selecting the same or similar conditions, such as heating power and measurement time, for different measurements.

[0009] In another embodiment, the determination of inclusions by the analysis processing circuitry further includes identifying the deviation between the heating of the micromechanical sensor and the reference heating by assigning a status report to the detected heating of the micromechanical sensor. The assigned status report may, for example, identify an erroneous value or an overall erroneous micromechanical sensor. For example, the measured value can be "geflagged," that is, identified as erroneous in the internal memory of the micromechanical sensor, which the analysis processing circuitry may include, for example, include. Consideration may be given to the possibility that if the analysis processing circuitry includes, for example, a microcontroller, the microcontroller can perform this marking or identification using the status report. Alternatively, identification can be performed via application software or an external data processing unit in a corresponding terminal device.

[0010] In another embodiment, calibration is performed based on multiple micromechanical sensors of the same type to detect a reference temperature. For this calibration, a reference temperature is determined for each of the multiple micromechanical sensors of the same type. The proposed invention provides high flexibility because calibration of the micromechanical sensor temperature can be performed in various ways during the heating process using a heating structure, wherein the heating is then configured as a reference temperature, and thus can be matched as well as possible to system and application requirements. In this configuration, calibration is performed by means of the collective behavior of multiple micromechanical sensors of the same type, wherein the sensors, for example, can all be configured as pressure sensors of the same model. This calibration can then be advantageously performed once, for example, based on a study of 1000 pressure sensors of the same model.

[0011] In another embodiment, calibration is performed based on a micromechanical sensor to detect a reference temperature. For this calibration, the reference temperature of the micromechanical sensor is determined at regular time intervals. The proposed invention offers high flexibility because calibration of the temperature of the micromechanical sensor can be performed in various ways during the heating process using a heating structure, wherein the heating is then configured as a reference temperature, and thus can be matched as well as possible to system and application requirements. In this configuration, calibration is performed using the individualized behavior of a single micromechanical sensor, which can be configured, for example, as a pressure sensor. This calibration can then advantageously be performed over a longer period, such as throughout the year, and the reference temperature of the micromechanical sensor can be detected at regular time intervals, such as daily. Alternative time intervals and calibration periods are also possible.

[0012] In another embodiment, the heating and reference heating of the micromechanical sensor are temperature parameters, respectively. The temperature parameter can be, for example, a directly measurable temperature, detected by at least one electronic component. Here, the at least one electronic component can also be integrated into the housing of the micromechanical sensor and effectively connected to the analysis and processing circuitry. Alternatively, the analysis and processing circuitry can also have at least one electronic component designed to detect the heating and reference heating of the micromechanical sensor. The at least one electronic component can be configured as a sensor, for example. Furthermore, the temperature parameter can also be an indirectly measured temperature, for example, via a voltage or current signal proportional to the heating, i.e., the sensor temperature, and can be detected by at least one electronic component, configured, for example, as a capacitor, resistor, and / or alternative components capable of achieving indirect temperature measurement.

[0013] In another embodiment, the heating structure is arranged on the surface of the analysis and processing circuitry of the micromechanical sensor, and the sensor element is arranged on the surface of the heating structure. Alternatively, the sensor element is arranged on the surface of the analysis and processing circuitry, and the heating structure is arranged on the surface of the sensor element. This achieves a compact construction of the micromechanical sensor overall, because the heating structure can be flexibly arranged and can be arranged not only within the housing, i.e., adjacent to the filling medium or in close proximity to the sensor element and / or analysis and processing circuitry, but also outside the housing. This variable placement capability of the heating structure can particularly advantageously affect the heating time and / or heating power used depending on the placement, and thus can, for example, reduce the required measurement time.

[0014] In another embodiment, the housing has at least one sidewall and a bottom region. A carrier element forms the bottom region, wherein the carrier element is particularly configured as a printed circuit board. The heating structure is at least partially adjacent to the sidewall and / or the carrier element. This generally achieves a compact construction of the micromechanical sensor because the heating structure can be flexibly arranged and can be arranged not only within the housing, i.e., adjacent to the filling medium or very close to the sensor element and / or analysis processing circuitry, and / or adjacent to the sidewall and / or carrier element within the housing, but also adjacent to the sidewall and / or carrier element outside the housing. Depending on the placement, this variable placement capability of the heating structure can particularly advantageously affect the heating time and / or heating power used, and thus can, for example, reduce the required measurement time.

[0015] The advantageous configurations and extensions of the invention set forth above and / or reproduced in advantageous embodiments may be used alone or in any combination thereof, except in cases where there is a unique and clear correlation or incompatible alternative. Attached Figure Description

[0016] The above-described features, characteristics, and advantages of the present invention, as well as the ways and methods of realizing these features, characteristics, and advantages, become clearer and more readily understood in conjunction with the following description of embodiments illustrated in more detail with reference to the schematic diagrams. The accompanying drawings show:

[0017] Figure 1a A schematic diagram of a method for detecting inclusions in a filling medium of a micromechanical sensor according to a first embodiment is shown.

[0018] Figure 1b Show Figure 1a A schematic diagram of a first extended scheme of a method for detecting inclusions in a filling medium for micromechanical sensors;

[0019] Figure 1c Show Figure 1a A schematic diagram of a second extended scheme of a method for detecting inclusions in a filling medium of a micromechanical sensor;

[0020] Figure 1d A schematic diagram of a method for detecting inclusions in a filling medium of a micromechanical sensor according to a second embodiment is shown;

[0021] Figure 1e Show Figure 1d A schematic diagram of a first extended scheme of a method for detecting inclusions in a filling medium for micromechanical sensors;

[0022] Figure 2a and 2bA schematic diagram of a sensor system is shown, which includes components for implementing the proposed... Figures 1a to 1d Micromechanical sensors using this method;

[0023] Figures 2c to 2d And 3 show Figure 2a and 2b Other schematic diagrams of the micromechanical sensors in the image.

[0024] It should be noted that these figures are schematic in nature and are not to scale. In this sense, parts and components shown in the figures may be depicted at an excessively large or reduced scale for better understanding. Furthermore, it should be noted that reference numerals in the figures are chosen to remain unchanged if identically constructed elements and / or parts are involved. Detailed Implementation

[0025] Figure 1a A schematic diagram of a method 100 for detecting inclusions 340 in a filling medium 330 of a micromechanical sensor 305 according to a first embodiment is shown. The method 100 includes: in a first step 105, providing a micromechanical sensor 305 having a sensor element 315, wherein the sensor element 315 is arranged in a housing 325 and the housing 325 includes a filling medium 330. The filling medium 330 surrounds the sensor element 315 and / or an adjacent heating structure 310. In a second step 110, the method 100 sets up a method to feed thermal energy Q by means of the heating structure 310 during a heating time t, wherein the filling medium 330 functions as a heat conductor for the sensor element 315 in a first operating mode 301. Additionally, an analysis processing circuit 320 may be arranged in the housing 325, which may be configured, for example, as an ASIC, wherein the filling medium 330 also functions as a heat conductor for the analysis processing circuit 320 and / or other components of the micromechanical sensor 305 within the housing 325 in the first operating mode 301. In the third step 115 of method 100, inclusions 340, particularly air inclusions, in the filling medium 330 are identified by detecting heating based on the heat energy Q fed during the heating time t by the micromechanical sensor 305.

[0026] The inclusion 340, in the second operating mode 302 of the filling medium 330, causes a change in the heat capacity of the micromechanical sensor 305 relative to the state without inclusion 340. Here, the heat capacity of the micromechanical sensor 305 can be calculated, for example, by adding the specific heat capacities of the materials used in the components of the micromechanical sensor 305. Subsequently, based on... Figures 2a to 2d as well as Figure 3 The components of the micromechanical sensor 305 are described.

[0027] Figure 1b It has been shown Figure 1aThe diagram shows a first extended embodiment of a method 100 for detecting inclusions 340 in a filling medium 330 of a micromechanical sensor 305. Figure 1a The third step 115 includes identifying inclusion 340, and now includes a first sub-step 120 and a second sub-step 125. The first sub-step 120 includes comparing the heating T of the micromechanical sensor 305 with a detected reference heating T0 based on the heat energy Q fed during the heating time t. The second sub-step 125 includes determining the presence of inclusion 340 if a deviation occurs between the heating T of the micromechanical sensor 305 and the reference heating T0.

[0028] Figure 1c Show Figure 1a A schematic diagram of a second extension of method 100 for detecting inclusions 340 in the filling medium 330 of a micromechanical sensor 305. Figure 1c In the second extension scheme, Figure 1b The second sub-step 125 includes a third sub-step 130. That is, the determination of the inclusion 340 further includes identifying the deviation between the heating T of the micromechanical sensor 305 and the reference heating T0 by assigning a status report to the detected heating T of the micromechanical sensor 305. The status report can, for example, be implemented as a so-called marker and integrated into the internal memory of the micromechanical sensor 305, and for example, identify the detected value of the heating T of the micromechanical sensor 305 as erroneous. Alternatively, it is also conceivable to apply the status report to the entire micromechanical sensor 305 and, for example, identify the micromechanical sensor 305 as erroneous.

[0029] The aforementioned identifiers can be implemented at the end user, for example, using application software, or alternatively, in the analysis and processing circuitry if it includes, for example, a microcontroller. The aforementioned heating T and reference heating T0 of the micromechanical sensor 305 are configured, for example, as temperature parameters, wherein the temperature parameters can be equivalent to a directly measured temperature or an indirectly measured temperature, such as a temperature measured by means of at least one electronic component via a voltage or current signal. Alternative configurations may also be considered.

[0030] Figure 1d A schematic diagram of a method 200 for detecting inclusions 340 in a filling medium 330 of a micromechanical sensor 305 according to a second embodiment is shown. The first step 205 can here be, for example, similar to... Figures 1a to 1c The first step 105 of method 100 is constructed accordingly. Similarly, the second step 210 can be constructed similarly or identically to the second step 110 of method 100; therefore, steps 205 and 210 are described above. Figures 1a to 1c Unlike the 100 methods shown therein, Figure 1d Method 200 may include a third step 215, i.e., calibration, which is performed to detect a reference temperature T0 for the micromechanical sensor 305. The calibration in the third step 215 may, for example, have been advantageously performed beforehand, so that only the calibration result can be used in the third step 215 of method 200.

[0031] Figure 1d The subsequent fourth step 220 in the middle can be, for example, equivalent to Figures 1a to 1c The third step 115 is to identify the inclusion 340. Figure 1d The first sub-step 225 and the second sub-step 230 can be, for example, similar to Figure 1b The first sub-step 120 and the second sub-step 125 are constructed in this way. That is, the heating T of the micromechanical sensor 305 can be compared with the reference heating T0 generated based on the heat energy Q fed during the heating time t detected in the third step 215, and if a deviation occurs between the heating T and the reference heating T0, it can be determined that there is a possible inclusion 340. Figure 1d Method 200 in the text is an exemplary selection and can also be used as described in other texts. Figures 1a to 1c Other method steps, or combinations thereof, as shown, may be included without prejudice to the invention.

[0032] Figure 1e Show Figure 1d A schematic diagram of a first extension of a method 200 for detecting inclusions 340 in a filling medium 330 of a micromechanical sensor 305. Here, the first extension relates to... Figure 1d The third step 215, namely, the calibration of the micromechanical sensor 305. The calibration performed for the reference temperature T0 used to detect the micromechanical sensor 305 can be performed, for example, in different ways. Therefore, in Figure 1e In branch 235, check whether calibration should be performed based on multiple micromechanical sensors 305 of the same type. If the check is affirmative, in Figure 1e The "y" branch indicates that, for calibration purposes, a reference temperature T0 is determined for each of the multiple micromechanical sensors 305 of the same type in the third sub-step 240. If the micromechanical sensor 305 is constructed, for example, as a pressure sensor, the reference temperature T0 can be determined for multiple pressure sensors of the same type and model, for example, 1000 sensors, using the proposed calibration. Therefore, it is possible to study the collective behavior of pressure sensors of the same type and use it for calibration, and advantageously perform it once.

[0033] In the case of a negative check result in branch 235, by Figure 1dThe "n" branch indicates that calibration is performed in the fourth sub-step 245 based on the obtained reference temperature T0 of the individual micromechanical sensor 305. For calibration, the reference temperature T0 of the individual micromechanical sensor 305 is therefore obtained at regular time intervals (e.g., daily) over a long period (e.g., a year). That is, in the fourth sub-step 245, the individualized behavior of the individual micromechanical sensor 305 is considered for calibration. Here, the micromechanical sensor 305 can be constructed as a pressure sensor as described above. Figure 1d and 1e Method 200 in [the original text] can be applied in the same way to [the following text] Figures 1a to 1c The method 100 shown is not limited to the exemplary illustration. For example, calibration can be performed under laboratory conditions, i.e., at a reference temperature of 25°C (room temperature) and a reference pressure of 980 mbar.

[0034] Figure 2a and 2b A schematic diagram of a sensor system 300 including a micromechanical sensor 305 is shown, which is suitable for implementation according to Figures 1a to 1d The method. The sensor system 300 includes a micromechanical sensor 305 and an adjacent heating structure 310, wherein, Figure 2a and 2b The heating structure 310 is integrated, for example, into the micromechanical sensor 305. The micromechanical sensor 305 includes a sensor element 315 for detecting a measured parameter to be sensed and an analysis and processing circuit 320, wherein the sensor element and the analysis and processing circuit are effectively interconnected. If the micromechanical sensor 305 is configured as a pressure sensor, the sensor element 315 includes, for example, a pressure-sensitive membrane for detecting external pressure. The pressure sensor element 315 configured as a pressure-sensitive membrane can, for example, have a vacuum-sealed cavity and is not shown in the figure illustrating a simplified schematic of the micromechanical sensor 305. The filling medium 330 is used here, in particular, to transfer pressure from the surrounding environment to the membrane of the sensor element 315.

[0035] Sensor element 315 and analysis processing circuitry 320, constructed, for example, in ASIC form, are arranged, for example, within housing 325 of micromechanical sensor 305. Housing 325 includes a filling medium 330, which is particularly configured as a protective gel and thereby protects micromechanical sensor 305 from environmental or mechanical influences such as moisture, particles, or chemicals. The filling medium 330 is used in micromechanical sensor 305, especially in areas directly exposed to the aforementioned environmental influences. Figure 2a and 2b In the illustration, the filling medium 330, for example, surrounds the sensor element 315, the analysis and processing circuitry 320, and the heating structure 310 adjacent to the sensor element 315. The sensor system 300 may, for example, have at least one... Figure 2aUsed for testing reference heating T0, or in other words Figure 2b The electronic component 335 used to detect the heating T is shown in these figures. At least one electronic component 335 is not arranged in the housing 325 of the micromechanical sensor 305, but is communicatively or effectively connected to the analysis and processing circuitry 320 and is configured, for example, as an external sensor.

[0036] However, alternatively, at least one electronic component 335 can be integrated into the housing 325 of the micromechanical sensor 305, so that the at least one electronic component 335 is also surrounded by the filling medium 330. In this alternative configuration, the at least one electronic component 335 can also be constructed as a sensor. Furthermore, the at least one electronic component 335 can be constructed, for example, as a capacitor, resistor, etc., and can be indirectly measured by a voltage or current signal proportional to heating, i.e., the temperature change of the micromechanical sensor 305. Furthermore, the analysis and processing circuit 320 can, for example, include at least one electronic component 335 in an integrated manner. The heating structure 310 is designed to feed thermal energy Q to the micromechanical sensor 305 during the heating time t, for example, to bring the micromechanical sensor 305 to an operating temperature different from, for example, room temperature of 25°C. Figure 2a The diagram shows a first operating mode 301 for the filling medium 330, in which the filling medium 330 functions as a thermal conductor for the sensor element 315 and the analysis and processing circuit 320. For example, in Figure 2a The reference temperature T0 detected by at least one electronic component 335 in the filling medium 330 of the micromechanical sensor 305 without inclusions can cause the micromechanical sensor 305 to experience a temperature rise of 20 Kelvin, or 20°C, by feeding heat energy Q through the heating structure 310 during the heating time t.

[0037] For example, the size of the heating structure 310 is approximately 0.1 mm. 2 Furthermore, with a heating time t of 10 seconds, the aforementioned temperature rise of 20 Kelvin, or 20°C, can be achieved. If the dimensions and / or position of the heating structure 310 deviate from this, other heating times t or other heating powers can be considered, thereby obtaining other values ​​for the temperature rise. Moreover, the corresponding heating time t is limited by the heating power used. The analysis and processing circuit 320 in... Figure 2bThe design is intended to identify inclusions 340, particularly air inclusions, within the filling medium 330, by means of at least one electronic component 335 detecting a temperature T in the micromechanical sensor 305 based on the thermal energy Q fed by the heating structure 310 during a heating time t. This can be done, for example, by recording a heating curve that illustrates the characteristic heating of the micromechanical sensor 305 for a given heating power.

[0038] Here, Figure 2b The inclusion 340 in the filling medium 330 operates in such a way that the heat capacity of the micromechanical sensor 305 is relative to Figure 2a The state of being free of inclusions is altered. Due to the change in heat capacity, the temperature characteristics of the micromechanical sensor 305 also change when heat energy Q is fed through the heating structure 310. If the sensor 305 is configured as a pressure sensor, the filling medium 330 exhibits particularly biased mechanical behavior under pressure and temperature changes in the second operating mode 302. This mechanical behavior, caused by the altered contact with the pressure-sensitive sensor element 315 due to inclusions 340, leads to errors in the detected pressure value of the pressure sensor.

[0039] Here, the analysis and processing circuit 320 is specifically designed to connect the heating T of the micromechanical sensor 305 with the temperature in the... Figure 2a The process compares the temperature T0 detected by at least one electronic component 335 with a reference temperature T0 (e.g., in the form of another detected heating curve) based on the heat energy Q fed during the heating time t (i.e., a comparison of two heating curves). If a deviation occurs between the temperature T of the micromechanical sensor 305 and the reference temperature T0, the analysis processing circuit 320 can determine the presence of an inclusion 340. For example, the deviation in the presence of inclusion 340 in the filling medium 330 can result in a twofold deviation in the operating temperature of the micromechanical sensor 305; that is, where a temperature rise of 20 Kelvin or 20°C could be detected previously, for example, in the absence of inclusion 340, this value now increases by two times in the presence of inclusion 340. Then, in the aforementioned example, the deviation will include 20 Kelvin or 20°C. If the temperature T or the reference temperature T0 is plotted as a heating curve, then, for example, in the presence of inclusion 340, the heating curve may deviate from the reference curve and describe a completely different curve trajectory. Alternatively, computer simulation can be considered, which can be used to determine the aforementioned deviation. For calibration with respect to the detected reference heating T0, it is possible to utilize... Figure 1e The variant shown is therefore described above.

[0040] Figure 2c and 2d as well as Figure 3 yes Figure 2a and 2b Other schematic diagrams of the micromechanical sensor 305 in the diagram. Figure 2c and 2d as well as Figure 3 The micromechanical sensor 305 in the image can also be constructed as a pressure sensor as described above. For example, in... Figure 2c , 2d Figures 3 and 4 show the second operating mode 302, which is characterized by the presence of inclusion 340, i.e., the filling medium 330. Unlike the previous figures, Figure 2c The heating structure 310 is arranged on the surface of the analysis and processing circuits 350 and 320 of the micromechanical sensor 305. For example, the heating structure 310 may cover approximately one-third of the surface of the analysis and processing circuits 350 and 320. The sensor element 315 is also arranged on the surface 355 of the heating structure 310. Additionally, in Figure 2c The bonding wire 345 used to electrically connect the sensor element 315 is shown in the figure. The bonding wire 345, or other bonding wires not shown, can also be used to connect the heating structure. Figure 2d Show Figure 2c The alternative configurations, in which, Figure 2d The sensor element 315 is arranged on the surface 350 of the analysis and processing circuit 320. The heating structure 310 is arranged on the surface 360 ​​of the sensor element 315.

[0041] and Figures 2a to 2d different, Figure 3 The micromechanical sensor 305 has multiple heating structures 310, the positions of which are deviated from the previous figures. Figure 3 The housing 325 has a first sidewall 365, a second sidewall 370, and a bottom region 375. It can be understood that the first sidewall 365 and the second sidewall 370 are not in... Figure 3 The micromechanical sensor 305 shown in the diagram has only surrounding walls forming its three-dimensional configuration. Therefore, the invention is not limited to... Figure 3 The diagram shows that the carrier element 377 forms the bottom region 375, and the carrier element 377 can be configured, for example, as a printed circuit board.

[0042] For example, the heating structure 380 can be dual-constructed, such that it is adjacent not only to the inner wall 385 of the first sidewall 365 but also to the outer wall 390 of the first sidewall 365. Furthermore, the heating structure 310 can, for example, be adjacent to the inner wall 392 of the second sidewall 370 of the housing 325. Additionally, the heating structure 310 can also be adjacent to the outer wall 394 of the bottom region 375. However, for the proposed invention, the heating structure 310 does not necessarily have to have... Figure 3 The structure shown is not limited to this; it can also be implemented with a configuration that deviates from it. Therefore, Figure 3This should only be illustrated schematically, showing which mounting possibilities are possible for the heating structure 310 on or within the micromechanical sensor 305. For example, the heating structure 310 adjacent to the outer sidewall 394 of the bottom region 375 could also be integrally constructed and have dimensional deviations from the heating structure 310 on the inner sidewall 392 of the second sidewall 370. These dimensional deviations could then result in different heating powers or heating times, so that the micromechanical sensor 305 is heated accordingly by feeding thermal energy Q. In particular, commonly used materials can be used for the micromechanical sensor 305, and the micromechanical sensor 305 itself can be fabricated using MEMS (Micro-Electro-Mechanical Systems) technology. The heating power mentioned for the heating structure 310 can be largely related to the corresponding application.

[0043] With the help of Figure 3 The structure of the heating structure 310 shown can also be considered to determine the location of inclusions 340 by selectively heating the heating structure 310. For example, if the heating structure 310 is installed at four different locations on or within the housing 325 of the micromechanical sensor 305, namely, on the side walls 365, 370 and in the bottom region 375, and then only one heating structure 310 at each determined location is operated. Subsequently, it can be gradually switched to operate the corresponding next heating structure 310 at different locations. Furthermore, if methods 100 and 200 are performed before the curing process of the filling medium 330, inclusions 340 may have already been identified and removed during the manufacturing process. It will no longer be possible to remove inclusions 340 later.

[0044] The invention has been described in detail through preferred embodiments. Other embodiments with different modifications or combinations of the described features may be considered instead of the described embodiments. For this reason, the invention is not limited to the disclosed examples, as other variations can be derived by those skilled in the art without departing from the scope of the invention.

[0045] List of reference numerals

[0046] 100 The method according to the first embodiment

[0047] 105 First Step

[0048] 110 Second Step

[0049] 115 Third Step

[0050] 120 First Sub-step

[0051] 125 Second Sub-step

[0052] 130 Third Sub-step

[0053] 135 Fourth Step

[0054] 200 Method according to the second embodiment

[0055] 205 First Step

[0056] 210 Second Step

[0057] 215 Third Step

[0058] 220 Fourth Step

[0059] 225 First Sub-step

[0060] 230 Second Sub-step

[0061] 235 branches

[0062] 240 Third Sub-step

[0063] 245 Fourth Sub-step

[0064] 300 sensor system

[0065] 301 First Working Mode

[0066] 302 Second Working Mode

[0067] 305 Micromachined Sensor

[0068] 310 Heating Structure

[0069] 315 Sensor Components

[0070] 320 Analysis and Processing Circuit

[0071] 325 housing

[0072] 330 Filling medium

[0073] 335 Electronic Components

[0074] 340 Mixed

[0075] 345 bond wire

[0076] 350 Surface of the analysis and processing circuit

[0077] Surface of 355 heating structure

[0078] Surface of 360 sensor element

[0079] 365 First sidewall

[0080] 370 Second sidewall

[0081] 375 Bottom Area

[0082] 377 Carrier Element

[0083] 380 Dual heating structure

[0084] 385 The inner sidewall of the first sidewall

[0085] 390 The outer wall of the first sidewall

[0086] 392 The inner sidewall of the second sidewall

[0087] 394 The outer wall of the bottom region

[0088] t Heating time

[0089] Q thermal energy

[0090] T heating

[0091] T0 Reference Heating

Claims

1. A method (100, 200) for detecting inclusions (340) in a filling medium (330) of a micromechanical sensor (305), the method comprising the steps of: A micromechanical sensor (305) with a sensor element (315) is provided (105, 205), wherein the sensor element (315) is arranged in a housing (325) and the housing (325) includes a filling medium (330) surrounding the sensor element (315) and / or an adjacent heating structure (310). During the heating time (t), thermal energy (Q) is fed by means of the heating structure (310), wherein the filling medium (330) functions as a thermal conductor (110, 210) for the sensor element in the first operating mode (301), wherein, in the first operating mode (301), a reference temperature (T0) is detected without inclusions in the filling medium (330) of the micromechanical sensor (305), and The inclusions (340) in the filling medium (330) are identified (115, 220) by detecting the heating (T) caused by the micromechanical sensor (305) based on the thermal energy (Q) fed during the heating time (t). In the second operating mode (302) of the filling medium (330), the inclusions (340) cause the heat capacity of the micromechanical sensor (305) to be changed relative to the state without inclusions.

2. The method (100, 200) according to claim 1. in, The identification (115, 220) of the inclusions (340) in the filling medium (330) further includes: Compare the heating (T) of the micromechanical sensor (305) (120, 225) with the reference heating (T0) detected based on the thermal energy (Q) fed during the heating time (t), and If a deviation occurs between the heating (T) of the micromechanical sensor (305) and the reference heating (T0), it is determined that there is an inclusion (340) at (135, 230).

3. The method (100, 200) according to claim 2. in, The determination of the inclusions (340) also includes: The deviation between the heating (T) of the micromechanical sensor (305) and the reference heating (T0) is identified by assigning a status report to the detected heating of the micromechanical sensor.

4. The method (100, 200) according to claim 2 or 3. in, To detect the reference heating (T0), calibration (235) is performed based on multiple micromechanical sensors of the same type. In order to perform the calibration, the reference heating of the micromechanical sensor (305) is determined for the multiple micromechanical sensors of the same type (240).

5. The method (100, 200) according to claim 2 or 3. in, To detect the reference heating (T0), calibration is performed based on the micromechanical sensor (305). In order to perform the calibration, the reference temperature (T0) of the micromechanical sensor (305) is determined at regular time intervals.

6. The method (100, 200) according to any one of claims 1 to 3. in, The heating (T) and the reference heating (T0) of the micromechanical sensor (305) are temperature parameters.

7. The method (100, 200) according to claim 1. in, The inclusion (340) is an air inclusion.

8. A sensor system (300), the sensor system comprising: - A micromechanical sensor (305) and an adjacent heating structure (310), wherein the micromechanical sensor (305) includes a sensor element (315) for detecting a measurement parameter to be sensed and an analysis and processing circuit (320). The sensor element (315) and the analysis and processing circuit (320) are arranged in a housing (325) and the housing (325) includes a filling medium (330) surrounding the sensor element (315) and / or the analysis and processing circuit (320) and / or the adjacent heating structure (310). - At least one electronic component (335) for detecting the heating (T) of the micromechanical sensor (305). The heating structure (310) is designed to feed thermal energy (Q) during the heating time (t), wherein the filling medium (330) functions as a thermal conductor for the sensor element (315) and / or the analysis and processing circuit (320) in the first operating mode (301), wherein in the first operating mode (301), a reference temperature (T0) is detected without inclusions in the filling medium (330) of the micromechanical sensor (305), and The analysis and processing circuit (320) is designed to identify inclusions (340) in the filling medium (330) by means of at least one electronic component (335) detecting the heating (T) of the micromechanical sensor (305) based on the thermal energy (Q) fed during the heating time (t). In the second operating mode (302) of the filling medium (330), the inclusions (340) cause the heat capacity of the micromechanical sensor (305) to be changed relative to the state without inclusions.

9. The sensor system (300) according to claim 8. in, The analysis and processing circuit (320) is also designed to compare the heating (T) of the micromechanical sensor (305) with a reference heating (T0) detected by the at least one electronic component (335) based on the thermal energy (Q) fed during the heating time (t), and The analysis and processing circuit (320) is designed to determine the presence of inclusions (340) if a deviation occurs between the heating (T) of the micromechanical sensor (305) and the reference heating (T0).

10. The sensor system (300) according to claim 8 or 9. in, The heating structure (310) is arranged on the surface (350) of the analysis and processing circuit of the micromechanical sensor (305), and The sensor element (315) is arranged on the surface (355) of the heating structure, or, The sensor element (315) is arranged on the surface (350) of the analysis and processing circuit, and The heating structure (310) is arranged on the surface (360) of the sensor element.

11. The sensor system (300) according to claim 8 or 9. in, The housing (325) has at least one sidewall (365, 370) and a bottom region (375). The carrier element (377) constitutes the bottom region (375), and The heating structure (310) is at least partially adjacent to the at least one sidewall (365, 370) and / or adjacent to the carrier element (377).

12. The sensor system (300) according to claim 8. in, The micromechanical sensor (305) is configured as a pressure sensor.

13. The sensor system (300) according to claim 8. in, The filling medium is constructed as a protective gel.

14. The sensor system (300) according to claim 8. in, The inclusion (340) is an air inclusion.

15. The sensor system (300) according to claim 11. in, The carrier element (377) is constructed as a printed circuit board.

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