Media sensor and method for producing media sensor

Abstract

The invention relates to a media sensor, comprising a sensor substrate having at least one sensor element arranged on a first surface of the sensor substrate and a cover substrate, the sensor substrate and the cover substrate being connected in a connection region, a cavity being formed between the cover substrate and the sensor substrate, the media sensor has at least one channel connecting the cavity to the environment, the channel extending substantially parallel to the first surface of the sensor substrate, the channel extending from a first opening outside the cavity to a second opening inside the cavity, the channel being arranged vertically at a distance from the connection region in the Z-direction, and / or the channel extending substantially parallel to the second surface of the sensor substrate. The channel is arranged in the connection region. The invention further relates to a method for producing a media sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to a medium sensor and to a method for producing a medium sensor. BACKGROUND

[0002] Medium sensors and methods for producing medium sensors are known from the prior art.

[0003] Medium sensors usually have a channel for transferring a medium to be measured into a cavity. It can happen when measuring a medium which can be ignited that the medium is ignited within the cavity. A flame which is ignited in the cavity can escape from the sensor through the channel and subsequently also ignite a medium outside the sensor.

[0004] A gas sensor for detecting combustible gases is known from DE 10 2005 020 131 B3. SUMMARY

[0005] It is therefore the task of the present application to provide an improved medium sensor and an improved method for producing a medium sensor. In particular, the task can be to provide an improved medium sensor with an improved flame barrier.

[0006] The task is solved by means of a medium sensor according to the application and a method for producing a medium sensor according to the application.

[0007] According to a first aspect of the application, a medium sensor is provided, which has a sensor substrate and a cover substrate. The sensor substrate has at least one sensor element. The sensor element is arranged on a first surface of the sensor substrate which faces the cavity. The sensor substrate and the cover substrate are connected in a connection region. A cavity is configured between the cover substrate and the sensor substrate. The medium sensor has at least one channel which connects the cavity with the environment. The channel extends essentially parallel to the first surface of the sensor substrate. The channel extends from a first opening outside the cavity to a second opening inside the cavity. Here, the channel is arranged spaced apart from the connection region in the Z direction and / or wherein the channel is arranged in the connection region.

[0008] Preferably, the terms such as essentially can be understood as a tolerance range of less than + / - 20° or percent, preferably less than + / - 10° or percent, and more strongly preferably less than + / - 5° or percent and especially less than + / - 1° or percent. The specification essentially always also discloses and includes the exactly mentioned values or curves of variation.

[0009] For example, the following technical advantage can be achieved thereby: An improved medium sensor is provided. In particular, the proposed medium sensor has an improved flame barrier. To this end, the medium sensor has a channel which extends substantially parallel to a first surface of the sensor substrate and which connects the environment to the cavity. The arrangement of the channel which extends substantially parallel to the first surface in particular provides the following advantage: The flame barrier can be improved structurally. Thus, the channel can be integrated into the medium sensor in different geometric embodiments, and the required flame barrier can additionally be implemented with greater design freedom. Furthermore, the channel which extends substantially parallel to the first sensor surface provides the following advantage: The channel can be integrated into the medium sensor lithographically and, if necessary, with the aid of thin layers and with high efficiency by means of planar technology. Thus, for example, a high density of very narrow channels can be produced.

[0010] In another embodiment, the channel has an extension length and a characteristic length dimension of the cross section which can be flowed through. Here, the ratio of the characteristic length dimension to the extension length of the channel is less than 1:30, and / or the characteristic length dimension is less than 10 pm, in particular less than 3 pm.

[0011] Here, the cross section which can be flowed through is in particular the cross section of the channel which extends substantially perpendicularly to the flow of the medium within the channel. The critical length of the cross section which can be flowed through can be regarded as the characteristic length dimension which significantly influences the volume flow in the channel. Thus, in the case of a circular cross section, the characteristic length dimension is the diameter. What can be regarded as the extension length is the length of the channel over which the cross section which can be flowed through extends in the medium sensor in an extended manner, or the path length which the medium needs to take in order to pass from the outer environment into the interior of the cavity.

[0012] For example, the following technical advantage can be achieved thereby: The medium sensor is subjected to a further improvement of the flame barrier. By arranging the channel parallel to the first surface of the sensor substrate, a ratio of the characteristic length dimension to the extension length of less than 1:30 can be achieved. Thus, a particularly effective flame barrier can be implemented for the medium sensor. Due to the significantly greater extension length compared to the characteristic length dimension, a high flow resistance can be set in terms of fluid mechanics and thus the propagation of a flame can be slowed down by means of a reduced volume flow in the channel. At the same time, the flame can be cooled along the channel wall. The simultaneous slowing down and cooling draw so much energy out of the flame that it is extinguished.

[0013] In another embodiment, the cross section which can be flowed through is substantially rectangular. The characteristic length dimension of the cross section which can be flowed through is a first side length of the rectangular cross section, wherein the first side length is less than a second side length.

[0014] For example, the following technical advantage can be achieved thereby: In addition to a good flame barrier effect, an improved heat dissipation can additionally be achieved in the channel. By virtue of the rectangular, flowable cross-sectional configuration, the volume flow can be reduced by means of the first edge length, and at the same time a large surface of the channel for the dissipation of heat in the channel can be achieved by means of the second edge length.

[0015] In another embodiment, the extension of the channel is arranged essentially in the XY plane and has a curved, in particular meandering or double helix-like course.

[0016] For example, the following technical advantage can be achieved thereby: In the case of a limited available installation space in the medium sensor, the extension can be significantly increased. By increasing the extension, the flame barrier effect of the sensor can be further improved.

[0017] In another embodiment, the channel is arranged in the sensor substrate, and the first opening of the channel is arranged on a first sensor substrate side and outside the cavity, and the second opening is arranged on the first sensor substrate side and inside the cavity. The channel extends essentially horizontally between the first opening and the second opening and extends vertically spaced apart from the connection region in the Z direction.

[0018] In another embodiment, the channel is arranged in the cover substrate, wherein the first opening of the channel is arranged on a first cover substrate side facing the sensor substrate and outside the cavity, wherein the second opening is arranged on the first cover substrate side and inside the cavity. Here, the channel extends essentially horizontally between the first opening and the second opening and is arranged vertically spaced apart from the connection region in the Z direction.

[0019] In another embodiment, the channel is arranged in the connection region, wherein the first opening of the channel is arranged on a first side of the connection region, wherein the channel extends essentially horizontally in the connection region up to the second opening into the cavity.

[0020] For example, the following technical advantage can be achieved thereby: The cover substrate and the sensor substrate do not undergo additional processing steps. Furthermore, the connection region provides a high degree of freedom in geometry for the configuration of the essentially horizontally extending channel.

[0021] In another embodiment, the sensor element is a heatable sensor element, and the heatable sensor element is configured for heating the medium in the cavity.

[0022] For example, the following technical advantage can be achieved thereby: The sensor response time is improved in terms of temporal dynamics or sensitivity.

[0023] In another embodiment, the sensor element has a pressure sensor element, and / or a thermal sensor element, and / or a speed sensor element, and / or a gas sensor element, and / or a thermal effect sensor element, and / or a heat conductivity probe, and / or an inductive sensor element, and / or a capacitive sensor element, and / or a resistive sensor element, and / or an optical sensor element, and / or a magnetic sensor element.

[0024] For example, it is possible to achieve the following technical advantage thereby: In the case of the use of a plurality of sensor elements, different properties of the medium can also be measured.

[0025] In another embodiment, the medium sensor has a housing and an exchange channel. The housing at least partially encloses the medium sensor, wherein the exchange channel is arranged in the housing. Here, the exchange channel is arranged in the housing in such a way that a fluid connection between the environment and the channel exists.

[0026] For example, it is possible to achieve the following technical advantage thereby: The medium sensor is particularly well protected from the outside environment. In addition to the cover substrate, the housing provides protection for the sensor substrate and the sensor elements. Here, the exchange channel in the housing ensures the fluid connection between the environment and the channel. Furthermore, it is also possible to provide the medium sensor with a further improvement of the flame barrier effect thereby.

[0027] According to a second aspect of the application, a method for producing a medium sensor is proposed. Here, the method comprises the following steps:

[0028] - providing a sensor substrate having at least one sensor element,

[0029] - providing a cover substrate,

[0030] - structuring a channel which extends essentially horizontally on the cover substrate and / or on the sensor substrate and / or in the connection region,

[0031] - connecting the sensor substrate with the cover substrate, wherein the sensor substrate and the cover substrate are connected in such a way that a cavity is structured between the sensor substrate and the cover substrate, wherein a first opening of the channel is arranged outside the cavity, wherein a second opening of the channel is arranged in the region of the cavity.

[0032] For example, it is possible to achieve the following technical advantage thereby: An improved method for producing a medium sensor is provided. The method is used in particular for producing a medium sensor having an improved flame barrier effect. The proposed method is a method which can be carried out by means of common semiconductor production steps and at the same time can provide an improved production of a medium sensor having an improved flame barrier effect.

[0033] In another embodiment, in an additional method step, a media sensor is embedded in a housing, and in another additional method step, an exchange channel is introduced into the housing.

[0034] For example, this can achieve the following technical advantages: providing a method for manufacturing a medium sensor with improved flame-blocking performance and simultaneously providing improved resistance or protection against external influences. Additionally, the flame-blocking performance can be further improved by means of an exchange channel. Attached Figure Description

[0035] The invention will now be described in more detail with reference to the exemplary drawings. Herein are shown:

[0036] - Figure 1 A simplified schematic diagram showing a side cross-sectional view of a medium sensor in an exemplary first embodiment is provided.

[0037] - Figure 2 A simplified schematic diagram showing a side cross-sectional view of a medium sensor in an exemplary second embodiment;

[0038] - Figure 3 Several simplified exemplary implementations of channels for a media sensor are shown in the top view;

[0039] - Figure 4 A further simplified schematic diagram showing a side cross-sectional view of the media sensor in the exemplary third embodiment;

[0040] - Figure 5 A top view showing an exemplary implementation variation of the channel used in the connecting area;

[0041] - Figure 6 A simplified schematic diagram showing a side cross-sectional view of the media sensor in an exemplary fourth embodiment;

[0042] - Figure 7 A simplified schematic diagram showing a side cross-sectional view of the media sensor in the exemplary fifth embodiment;

[0043] - Figure 8 A simplified schematic diagram showing a side cross-sectional view of the medium sensor in the exemplary sixth embodiment;

[0044] - Figure 9 A greatly simplified schematic flowchart is shown for a method of manufacturing a medium sensor. Detailed Implementation

[0045] Figure 1 A simplified schematic diagram of a side cross-sectional view of a medium sensor 1 in an exemplary first embodiment is shown.

[0046] In the subsequent figures reference is made to a rectangular coordinate system. This coordinate system has a Z-direction (axis), an X-direction (axis) and a Y-direction (axis).

[0047] The medium sensor 1 has a sensor substrate 10 and a cover substrate 20. Between the sensor substrate 10 and the cover substrate 20 a cavity 15 is configured. The sensor substrate 10 and the cover substrate 20 are functionally connected to each other in a connection region 30. The connection region 30 serves to mechanically firmly and relative to the environment sealingly connect the cover substrate 20 and the sensor substrate 10. To this end, the connection region 30 can be configured, for example, as a bonding frame made of sealing glass. On a first surface 12 of the sensor substrate 10 facing the cavity 15 a sensor element 11 is arranged. The sensor element 11 serves to measure a state variable of the medium in the cavity 15.

[0048] Preferably, there can also be a plurality of sensor elements 11 on the first surface 12 of the sensor substrate 10. Thus, for example, the sensor element can have a pressure sensor element, and / or a thermal sensor element, and / or a speed sensor element, and / or a gas sensor element, and / or a thermal effect sensor element, and / or a thermal conductivity probe, and / or an inductive sensor element, and / or a capacitive sensor element, and / or a resistive sensor element, and / or an optical sensor element, and / or a magnetic sensor element. Thus, the medium sensor 1 can be used to measure the state of different medium properties in the cavity 15. It is particularly preferred that a gas can be measured as a medium in the cavity 15. That is, the medium sensor can be configured as a gas sensor. To this end, the sensor element 11 can be a sensor element 11 that can be heated in order to heat the medium or gas in the cavity 15. Advantageously, the response time of the medium sensor 1 can thereby be improved.

[0049] In order to transfer a medium from the environment into the cavity 15, or in order to ensure an exchange of the surrounding medium with the cavity, the medium sensor 1 has a channel 40. The channel 40 can also be referred to as a diffusion channel. If the sensor element 11 is a sensor element that can be heated and the medium to be measured in the cavity 15 is a flammable gas, it can occur that an ignition of the gas takes place within the cavity 15. In order to prevent the flame from spreading from the cavity 15 into the environment, the channel 40 is arranged in the medium sensor in a special manner.

[0050] That is, the channel 40 serves, inter alia, to ensure a flame barrier. To this end, the channel 40 extends substantially parallel to the first surface 12 of the sensor substrate 10. The channel 40 extends from a first opening 41 outside the cavity 15 to a second opening 42 inside the cavity 15. In other words, the channel 40 connects the environment with the cavity 15 and extends horizontally in this sectional view. In this embodiment, the channel 40 is arranged vertically spaced apart from the connection region 30 in the Z direction 52. The channel 40 has an extension length 46 and a characteristic length dimension 47 of the cross section that can be flowed through. In this embodiment, the extension length 46 is unambiguously defined along the X direction 50 In this embodiment, the characteristic length dimension 47 is configured along the Z direction 52. The extension length 46 that can be considered is the extension of the cross section that can be flowed through or the path length that a medium needs to travel in order to get from the outside environment to the inside of the cavity 15. The characteristic length dimension 47 that can be considered is the length dimension of the channel 40, which is defined as a critical length for the volume flow in the channel. Thus, the characteristic length dimension 47 that can be considered is, for example, the diameter or, in the case of a rectangular channel, the first side length, wherein the first side length is the smaller side length than the second side length of the rectangular cross section.

[0051] In order to provide a particularly effective flame barrier for the medium sensor 1, the ratio of the characteristic length dimension 47 to the extension length 46 of the channel 40 is preferably less than 1:30 and / or at least one cross-sectional characteristic length dimension is less than 10 pm, in particular less than 3 pm. Thus, advantageously, in the case of a characteristic length dimension 47 of 10 pm, the extension length 46 can accordingly be at least 300 pm or more. In the case of a characteristic length dimension 47 of 3 pm, the extension length 46 can preferably accordingly be at least 90 pm or more.

[0052] In this embodiment, the channel 40 is arranged in the sensor substrate 10 and the first opening 41 of the channel 40 is arranged on the first sensor substrate side 13 and outside the cavity 15, wherein the second opening 42 is likewise arranged on the first sensor substrate side 13 and inside the cavity 15.

[0053] In another embodiment variant of the medium sensor 1, a plurality of channels 40 can also be provided in the sensor substrate. It can thus be considered that four, ten or more channels 40 are also provided in the medium sensor 1. By increasing the number of channels 40, the diffusion medium exchange rate of the cavity volume can be increased, which improves the response time. At the same time, it can be ensured by means of a large extension length 46 and a small characteristic length dimension 47 that there is sufficient flow resistance against the propagation of a flame.

[0054] Thus, by providing at least one channel 40 arranged substantially parallel to the first sensor surface 12, it is possible to provide the medium sensor 1 in a manner having an improved flame barrier effect.

[0055] Figure 2 A simplified schematic diagram showing a lateral sectional view of a medium sensor 1 in an exemplary second embodiment.

[0056] The construction of the medium sensor 1 is similar to that of the medium sensor 1 in Figure 1 The medium sensor 1 comprises a sensor substrate 10 and a cover substrate 20. The sensor substrate 10 and the cover substrate 20 are functionally connected to one another in a connection region 30. On a first surface 12 of the sensor substrate 10, in turn, a sensor element 11 is provided. The cover substrate 20 and the sensor substrate 10 are arranged such that a cavity 15 is configured. The cavity 15, in turn, serves to accommodate a medium, the state variable of which is detected by means of the sensor element 11. Exemplarily, the sensor element 11 is, in turn, a sensor element 11 that can be heated in order to ensure an improved response time of the medium sensor 1.

[0057] Unlike Figure 1 In this embodiment, in turn, the channel 40 is provided in the cover substrate 20. The channel 40, in turn, extends substantially parallel to the first surface 12 of the sensor element 10. Exemplarily, a first opening 41 of the channel 40 is arranged on a first cover substrate side 25 facing the cavity 15 and outside the cavity 15. A second opening 42 is likewise arranged on the first cover substrate side 25 and inside the cavity 15. Here, the channel 40 extends substantially parallel to the first surface 12 between the first opening 41 and the second opening 42 and is arranged vertically spaced apart from the connection region 30 in the Z direction 52. The channel 40, in turn, has a characteristic length dimension 47 and an extension length 46. Preferably, the ratio of the characteristic length dimension 47 to the extension length 46 is, in turn, less than 1:30 and / or the characteristic length dimension 47 is less than 10 pm, in particular less than 3 pm. Thereby, it is possible to provide the medium sensor 1 with a particularly efficient flame barrier effect. The first opening 41 of the channel 40 need not necessarily be provided on the first cover substrate side 25. For example, the first opening 41 can also be provided on the second cover substrate side 26. For example, the extension length 46 of the channel 40 extends completely in the X direction 50. The extension length 46 need not necessarily extend purely in the X direction 50. For example, it is also conceivable that the extension length extends in the XY plane in a curved manner. Various implementation variants are conceivable for the channel 40. The cross section of the channel 40 that can be flowed through can be configured in different variants.

[0058] Some of these possible and conceivable implementation variants for the channel 40 are explained in more detail in the following Figure 3 Some of these possible and conceivable implementation variants for the channel 40 are explained in more detail in the following

[0059] Figure 3 In a top view, a plurality of simplified exemplary embodiments of a channel 40 for a media sensor 1 are shown.

[0060] The media sensor 1 substantially corresponds to the media sensor in Figure 1 In a top view of the partial sectional view, a sensor substrate 10 with a sensor element 11 is shown. Exemplarily, the connection region 30 is shown as a smooth line course. A not shown cover substrate is connected to the sensor substrate 10 in the connection region 30. The connection region 30 delimits a cavity 15.

[0061] Exemplarily, in this embodiment, the media sensor 1 has three channels 40. Exemplarily, the channels 40 are provided in the sensor substrate 10. The channels 40 connect the environment with the cavity 15. It is exemplarily shown that the channels 40 can also have a meandering or curvilinear course in the XY plane. To this end, exemplarily, a second channel 8 and a third channel 9 are shown which have a meandering or curvilinear course in the XY plane. It is also conceivable that the first channel 7 extends, for example, linearly in the XY plane and only in the X direction 50. The meandering or curvilinear course of the channels 40 can serve to increase the extension length 46 of the cross section which can be flowed through.

[0062] On the right side of Figure 3 A-A, a sectional view of a channel 40 is schematically shown which has an exemplary flowable cross section 45. The channel 40 has a first side length 48 and a second side length 49. Exemplarily, the flowable cross section 45 of the channel 40 is shown substantially rectangularly. For the flowable cross section 45, the first side length 48 is decisive as characteristic length 47. Preferably, the first side length 48 is smaller than the second side length 49. Thereby, the following advantages can be achieved: By the smaller first side length 48, a high flow resistance is provided, and at the same time, by the larger second side length 49, the surface of the flowable cross section 45 is increased, and thus also a higher heat dissipation via the delimiting wall of the channel 40 can be achieved.

[0063] This embodiment serves only as an exemplary embodiment for the channel 40 or its course. Different structural measures for the channel 40 can be realized and can be considered. Thus, depending on the available construction space and construction conditions, the channel 40 can also be configured circularly, elliptically or quadrangularly.

[0064] Figure 4 A further simplified schematic of a lateral sectional view of a media sensor 1 in an exemplary third embodiment is shown.

[0065] The media sensor 1 has a sensor substrate 10 and a cover substrate 20. In this embodiment, the cover substrate 20 is configured as an ASIC evaluation unit 21. The ASIC evaluation unit 21 can have, for example, plated-through holes 22. Furthermore, solder balls 23 can be provided on the ASIC evaluation unit 21 for external electrical contacting.

[0066] The sensor substrate 10 has, in turn, a sensor element 11 on a first surface 12 facing the cavity. A cavity 15 is provided in turn between the sensor substrate 10 and the cover substrate 20. The cover substrate 20 or the ASIC evaluation unit 21 and the sensor substrate 10 are connected to one another in a connection region 30.

[0067] In this embodiment, a channel 40 is provided in the connection region 30. The channel 40 extends in turn substantially parallel to the first surface 12 of the sensor substrate 10. Furthermore, the channel 40 extends from a first opening 41 outside the cavity 15 to a second opening 42 inside the cavity 15. Here, the first opening 41 of the channel 40 is arranged on the first side 31 of the connection region 30, and the channel 40 extends substantially horizontally or in the XY plane through the connection region 30 to the second opening 42.

[0068] The channel 40 can extend through the connection region 30 in turn in different ways. Here, it is again preferred that the extension length of the conduit 40 is many times larger than the characteristic length dimension of the cross section of the channel 40 that can be flowed through. Here, the channel 40 can extend in the Z direction over a partial height or the entire height of the connection region. It is thus also ensured in this embodiment variant that the media sensor 1 has a high flame protection effect.

[0069] Exemplary embodiment variants for the course of the channel 40 within the connection region 30 are described in the following Figure 5 .

[0070] Figure 5 A top view is shown of an exemplary course form of the channel 40 through the connection region 30, which is shown here as a frame element.

[0071] The top view is shown in the XY plane. The media sensor 1 is shown in a partial cutaway view and in two different embodiments. The media sensor 1 has a sensor substrate 10 on which a sensor element 11 is arranged. Furthermore, a connection region 30 is shown. The connection region 30 encloses a cavity 15. In order to ensure the exchange of media of the environment with the cavity 15, a channel 40 is provided in the connection region 30.

[0072] In the first embodiment on the left side of the drawing, the first openings 41 of the channels 40 are arranged on the first side of the connection region 30 and the channels 40 extend substantially in the X direction 50 towards the second openings 42 in the cavity. It is shown exemplarily that in the connection region 30 three first openings 41 and three second openings 42 for three channels 40 can also be provided.

[0073] In the second embodiment on the right side of the drawing, the first openings 41 of the channels 40 are arranged on the first side of the connection region 30. In contrast to the embodiment on the left side of the drawing, in this embodiment the channels 40 extend in the XY plane through the entire connection region 30 and end at the second openings 42 in order to connect the cavity 15 with the environment. That is, the channels 40 have a curved course. The second openings 42 are provided on the opposite side of the first openings 41 in the connection region 30. Thereby, it is shown exemplarily that a large extension length 46 can be achieved in the connection region 30. The extension length 46 is shown exemplarily as a line within the channels 40. The large extension length 46 in turn serves to ensure a high heat dissipation within the channels 40 for the medium sensor 1.

[0074] Figure 6 A simplified schematic diagram of a lateral sectional view of the medium sensor 1 in an exemplary fourth embodiment is shown.

[0075] The medium sensor 1 substantially corresponds to the medium sensor 1 in Figure 1 which has a package in the form of an LGA (land grid array) housing or a QFN (quad flat no leads) housing. In order to avoid repetitions here, only the differences of the medium sensor 1 to the medium sensor 1 in Figure 1 are discussed. Of course, the implementation variants of the medium sensor 1 in the further figures can also be used in this embodiment.

[0076] In this embodiment, the medium sensor 1 additionally has a housing 2. The housing 2 at least partially surrounds the medium sensor 1. For example, the housing 2 can be a casting compound and consist of an organic binder with inorganic glass particles. Furthermore, the casting compound or the housing 2 has an exchange opening 3. The exchange opening 3 is fluidically connected to the channels 40. Through the exchange opening 3 it can be ensured that the medium sensor 1 can continue to detect the medium from the environment. The casting compound or the housing 2 can serve as an additional protection of the medium sensor 1 against environmental influences. The medium sensor 1 can be fastened together with the housing 2 or the casting compound on the circuit board substrate 4.

[0077] Figure 7 A simplified schematic diagram of a lateral sectional view of the medium sensor 1 in an exemplary fifth embodiment is shown.

[0078] The medium sensor 1 substantially corresponds again to the medium sensor in Figure 1 . In order to avoid repetitions, here only the differences of the medium sensor 1 to the medium sensor in Figure 1 are discussed. Of course, the implementation variants of the medium sensor 1 in the further figures can also be used in this implementation.

[0079] The medium sensor again has a housing 2. In this implementation variant, the housing 2 consists of a circuit board substrate 4 and a metal cover substrate 5. Here, the circuit board substrate is so constructed that again an exchange opening 3 is provided. In this case, the exchange opening 3 is not directly connected to the channel 40, but to a further channel 6 within the circuit board substrate. The further channel 6 and the channel 40 are fluidically connected within the circuit board substrate 4. Furthermore, within the circuit board substrate 4, ceramic particles can also be provided between the further channel 6 and the channel 40. In addition, the ceramic particles can reduce the propagation of a flame from the cavity 15 and prevent the intrusion of pollutants or undesired particles from the environment into the cavity 15.

[0080] That is, by providing the exchange opening 3, the further channel 6, the channel 40 and the additional ceramic particles within the housing 2, a particularly efficient medium sensor 1 can be provided. In addition, solder balls 23 or also solder pins can be provided on the circuit board substrate for contacting electrical contacts of an external unit.

[0081] Figure 8 A simplified schematic diagram showing a lateral sectional view of the medium sensor 1 in the exemplary sixth implementation.

[0082] The medium sensor 1 substantially corresponds again to the medium sensor in Figure 1 . In order to avoid repetitions, here only the differences of the medium sensor 1 to the medium sensor in Figure 1 are discussed. Of course, the implementation variants of the medium sensor 1 in the further figures can also be used in this implementation.

[0083] The medium sensor 1 has an ASIC evaluation unit 21 as a cap substrate 20. The medium sensor 1 is encapsulated in an eWLB (embedded Wafer level Ball Grid Array) housing 2. The housing 2 again at least partially encloses the medium sensor 1. In this implementation, a cast compound with a RDL (redistribution layer) cover is provided as the housing 2. Furthermore, in the housing 2 again an exchange opening 3 is provided for fluidically connecting the environment with the channel 40. On the RDL cover solder balls 23 can be provided for an external contact connection.

[0084] Figure 9 A highly simplified schematic flow chart illustrating a method 100 for manufacturing a media sensor.

[0085] The method 100 is used for manufacturing a media sensor and can be used, in particular, for manufacturing a media sensor having an improved flame guard barrier. Herein, the method 100 comprises the following steps.

[0086] In a first method step 110, a sensor substrate having at least one sensor element is provided.

[0087] In a second method step 120, a cover substrate is provided.

[0088] In a third method step 130, a channel extending essentially horizontally is structured on and / or in the cover substrate and / or on and / or in the sensor substrate and / or in the connection region.

[0089] In a fourth method step 140, the sensor substrate and the cover substrate are connected to each other such that a cavity is structured between the sensor substrate and the cover substrate. Herein, a first opening of the channel is arranged outside the cavity and a second opening of the channel is arranged in the region of the cavity.

[0090] In an optional fifth method step 150, the media sensor is embedded into a housing.

[0091] In a further additional and optional method step 160, an exchange channel is introduced into the housing.

[0092] That is, the method 100 is an efficient method for producing a media sensor which can have, in particular, an improved flame guard barrier. The method 100 can be performed by means of common semiconductor production processes.

[0093] Although the present application has been described in accordance with specific embodiments thereof, those skilled in the art will be able to devise numerous alternative embodiments without departing from the core of the application.

Claims

1. Medium sensor (1) having a sensor substrate (10) and a cover substrate (20), wherein the sensor substrate (10) having at least one sensor element (11), wherein the sensor element (11) is arranged on a first surface (12) of the sensor substrate (10), wherein the sensor substrate (10) and the cover substrate (20) are connected in a connection region (30), wherein a cavity (15) is configured between the cover substrate (20) and the sensor substrate (10), wherein the medium sensor (1) has at least one channel (40) connecting the cavity (15) with the environment, wherein the channel (40) extends essentially parallel to the first surface (12) of the sensor substrate (10), wherein the channel (40) extends from a first opening (41) outside the cavity (15) to a second opening (42) inside the cavity (15), wherein the channel (40) is arranged essentially vertically spaced apart from the connection region (30) in a Z direction (52), and / or wherein the channel (40) is arranged in the connection region (30).

2. The media sensor (1) according to claim 1, wherein The channel (40) has an extension length (46) and a characteristic length dimension (47) of a flowable cross section (45), wherein the ratio of the characteristic length dimension (47) to the extension length (46) is less than 1:30, and / or wherein the characteristic length dimension is less than 10 pm, in particular less than 3 pm.

3. The media sensor (1) according to claim 2, wherein The flowable cross section (45) is essentially rectangular, wherein the characteristic length dimension (47) of the flowable cross section (45) is a first side length (48) of the rectangular cross section, wherein the first side length (48) is smaller than a second side length (49).

4. The media sensor (1) according to any one of claims 2 or 3, wherein The extension length (41) of the channel (40) essentially extends in an XY plane and has a curved, in particular meandering, course.

5. Medium sensor (1) according to any one of the preceding claims, wherein The channel (40) is arranged in the sensor substrate (10), wherein the first opening (41) of the channel (40) is arranged on a first sensor substrate side (13) and outside the cavity (15), wherein the second opening (42) is arranged on the first sensor substrate side (13) and inside the cavity (15), wherein the channel (40) extends essentially horizontally between the first opening (41) and the second opening (42) and is arranged essentially vertically spaced apart from the connection region (30) in the Z direction (52).

6. The media sensor (1) according to any one of claims 1 to 4, wherein The channel (40) is arranged in the cover substrate (20), wherein the first opening (41) of the channel (40) is arranged on a first cover substrate side (25) and outside the cavity (15), wherein the second opening (42) is arranged on the first cover substrate side (25) and inside the cavity (15), wherein the channel (40) extends substantially horizontally between the first opening (41) and the second opening (42) and is arranged vertically spaced apart from the connection region (30) in the Z direction (52).

7. The media sensor (1) according to any one of claims 1 to 4, wherein The channel (40) is arranged in the connection region (30), wherein the first opening (41) of the channel (40) is arranged on a first side (31) of the connection region (30), wherein the channel (40) extends substantially horizontally through the connection region (30) up to a second opening (42) into the cavity (15).

8. Medium sensor (1) according to any one of the preceding claims, wherein The sensor element (11) is a heatable sensor element, wherein the heatable sensor element is configured for heating a medium in the cavity (15).

9. Medium sensor (1) according to any one of the preceding claims, wherein The sensor element (11) is a pressure sensor element, and / or a thermal sensor element, and / or a speed sensor element, and / or a gas sensor element, and / or a thermal effect sensor element, and / or a thermal conductivity probe, and / or an inductive sensor element, and / or a capacitive sensor element, and / or a resistive sensor element, and / or an optical sensor element, and / or a magnetic sensor element.

10. Medium sensor (1) according to any one of the preceding claims, wherein The medium sensor (1) has a housing (2) and an exchange channel (3), wherein the housing (2) at least partially encloses the medium sensor (1), wherein the exchange channel (3) is provided in the housing (2), wherein the exchange channel (3) is provided in the housing (2) in such a way that a fluid connection exists between the environment and the channel (40).

11. Method (100) for producing a medium sensor (1), the method comprising the following steps: - providing (110) a sensor substrate (10) having at least one sensor element (11), - providing (120) a cover substrate (20), - configuring (130) a channel (40) extending substantially horizontally on the cover substrate (20) and / or on the sensor substrate (10) and / or in a connection region (30), - connecting (140) the sensor substrate (10) with the cover substrate (20), wherein The sensor substrate (10) and the cover substrate (20) are connected in such a way that a cavity (15) is configured between the sensor substrate (10) and the cover substrate (20), wherein a first opening (41) of the channel (40) is arranged outside the cavity (15), wherein a second opening (42) of the channel (40) is arranged in a region of the cavity (15).

12. The method of claim 12, wherein, In a further method step (150), the medium sensor (1) is embedded in a housing (2), wherein, in an additional method step (160), an exchange channel (3) is introduced into the housing (2).

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