Method for manufacturing a sensor and sensor

Abstract

The present disclosure relates to a method for manufacturing a sensor, wherein the sensor has a sensing element and a housing, wherein the housing has an interior space which is accessible through a housing opening, and wherein the sensing element is arranged in the interior space and is configured for detecting a property and / or a composition of an ambient medium of the sensor, the method comprising: filling a protective medium into the interior space through the housing opening, wherein the protective medium is configured for transmitting the property and / or the composition of the ambient medium to the sensing element, fixing a preferably flexible membrane on or in the housing opening, preferably for closing the housing opening, wherein the membrane has at least one membrane opening, and closing the at least one membrane opening. The present disclosure also relates to a sensor which is manufactured according to such a method.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a sensor, wherein the sensor has a sensing element and a housing, wherein the housing has an internal space accessible through an opening in the housing, and wherein the sensing element is arranged in the internal space and configured to detect the properties and / or composition of the surrounding environmental medium of the sensor.

[0002] The present invention also relates to a sensor. Background Technology

[0003] Although the invention can generally be applied to any sensor that can detect the properties and / or composition of the surrounding environmental medium, this disclosure is illustrated with reference to a pressure sensor.

[0004] Pressure sensors are widely used in consumer electronics, such as smartphones and smartwatches. Driven by new applications like indoor navigation and fitness tracking, the demand for higher measurement accuracy from pressure sensors is constantly increasing. Simultaneously, new generations of devices are constructed to be media-sealed and contamination-proof, necessitating high-precision and media-sealed pressure sensors. Similarly, pressure sensors need to become as dirt-prone as possible throughout their lifespan to ensure trouble-free functionality. Therefore, the surfaces of the sensing mechanism exposed to the surrounding environmental media should have the lowest possible tendency to contaminate.

[0005] To achieve high-precision and well-miniaturized sensors, it is known to construct the sensing element of the sensor as a MEMS (Micro-Electro-Mechanical System). This is for achieving media-sealed sensors. The sensing element can be embedded in a protective medium and thereby protected from direct contact with the surrounding environment. Known protective media are formed of gels or oils. Additionally, the protective medium has the function of transmitting the properties and / or composition of the surrounding environment to the sensing element, enabling the detection of these properties and / or composition. It is known to protect the surface of the protective medium that is in contact with the surrounding environment using a diaphragm. In the case of a fluid as the protective medium, the diaphragm additionally prevents the outflow of the protective medium.

[0006] When using a diaphragm, it is essential to ensure that there are as few air bubbles as possible remaining between the protective medium and the diaphragm. According to known solutions, the sensor housing has a filling opening and a suction opening. The protective medium is filled into the internal space through the filling opening, and excess air is suctioned out through the suction opening. After filling the internal space with the protective medium, the filling opening and suction opening are sealed, for example, with a plug. The disadvantage here is that the manufacturing of the sensor housing becomes more expensive due to the additional openings. Summary of the Invention

[0007] In one embodiment, the present invention provides a method for manufacturing a sensor, wherein the sensor has a sensing element and a housing, wherein the housing has an internal space accessible through an opening in the housing, and wherein the sensing element is arranged in the internal space and configured to detect the properties and / or composition of the surrounding environmental medium of the sensor, the method comprising: • A protective medium is filled into the internal space through the housing opening, wherein the protective medium is configured to transmit the properties and / or composition of the surrounding environmental medium to the sensing element. • A preferably flexible (nachgiebig) diaphragm is fixed to or into the housing opening, preferably to close the housing opening, wherein the diaphragm has at least one diaphragm opening, and • Close the at least one membrane opening.

[0008] In another embodiment, the present invention provides a sensor, preferably a pressure sensor, which is manufactured by means of the method according to the foregoing embodiments.

[0009] The sensor is provided as a "sensor blank" prior to the filling of the protective medium, the fixing of the diaphragm, and the closure of at least one diaphragm opening. The sensor includes a housing having an internal space and a housing opening. A sensing element is arranged within the internal space. The housing opening serves as an entrance to the internal space. This means, on the one hand, that the properties and / or composition of the surrounding environmental medium can reach the sensing element directly or indirectly from outside the sensor through the housing opening. On the other hand, this entrance allows the filling of the internal space with the protective medium.

[0010] Regarding the order of filling the protective medium and fixing the diaphragm, the following should be noted: In one embodiment, filling the protective medium can be performed before fixing the diaphragm. This allows for a particularly good inlet for filling the protective medium. In another embodiment, fixing the diaphragm is performed before filling the protective medium. At least one diaphragm opening is available for filling the protective medium.

[0011] The diaphragm can be formed from different materials. In one embodiment, the diaphragm is formed from metal. In another embodiment, the diaphragm is formed from plastic. Particularly suitable for pressure sensors is that the diaphragm is as flexible as possible. Here, the diaphragm can have a low elastic modulus, be thin (e.g., one to tens of micrometers thick), and / or be structured, for example, by a wavy profile.

[0012] The diaphragm already has "at least one diaphragm opening." This can mean that one or more diaphragm openings were created during the manufacture of the diaphragm. The number of diaphragm openings can depend on the intended application. If the protective medium is filled through a diaphragm opening via a thin sleeve (Kanüle), a single diaphragm opening may be suitable. If the protective medium is filled through a diaphragm opening via a thin sleeve, and gas, such as air, is extracted from the internal space through another diaphragm opening, two diaphragm openings may be suitable. If the sensor is degassed before sealing, for example by applying negative pressure, multiple diaphragm openings may be suitable. In general, the number of diaphragm openings can therefore depend on the specific application and / or be used for different purposes.

[0013] One or more diaphragm openings can be shaped differently, as long as they fulfill the functions required by this disclosure. The boundaries of the one or more diaphragm openings can, in principle, be arbitrarily shaped. In one embodiment, the one or more diaphragm openings have continuous boundaries. Such diaphragm openings can, for example, be constructed as circular or elliptical. In this way, the stability of the diaphragm is minimized.

[0014] The "fixing of the diaphragm to or within the housing opening" can be achieved in various ways. Here, a fixing region can be constructed on or within the housing opening, and the diaphragm can be fixed to said fixing region. How the fixing region is constructed depends particularly on the type of fixing and positioning of the fixing region relative to the housing opening. The diaphragm can be welded to the fixing region or otherwise material-locked (stoffschlüssig) connected, and / or can be clamped to the fixing region or held in other mechanical ways. Here, it may be suitable to establish a media-sealed connection between the diaphragm and the housing opening after fixing.

[0015] The closure of at least one diaphragm opening can be achieved in various ways. Preferably, the diaphragm opening is closed in such a way that the protective medium can no longer leave the internal space. The closed diaphragm opening can be constructed to be airtight and / or liquid-tight, or generally media-tight. Furthermore, a diaphragm opening closed by a filler can be constructed as stably as, or even more stably than, a diaphragm without one or more openings. The materials used for the filler for closure depend particularly on the material of the diaphragm. The specific steps of the closure process depend on the material used for the filler used to close at least one diaphragm opening. The filler for the diaphragm opening can be thin. In one embodiment, the thickness of the filler is between 5 and 50 micrometers, for example, 10 or 20 micrometers.

[0016] The "sensing element" can be implemented in various ways, as long as it can detect the properties and / or composition of the surrounding environmental medium. These properties and / or composition can be, for example, the pressure, temperature, concentration, and / or humidity of gases such as carbon dioxide or carbon monoxide, to name just a few conceivable implementations. The sensing element can be correspondingly diverse, and a sensor can have multiple different sensing elements. The sensing element can be constructed as a MEMS (microelectromechanical system), thereby enabling the realization of particularly compact sensors.

[0017] Other features, advantages and other embodiments of the invention are described below or will become apparent therefrom.

[0018] In one embodiment, the protective medium is degassed (Entgasen) before the closure of at least one membrane opening, wherein the degassed protective medium is preferably performed by applying a negative pressure to at least one membrane opening. In this way, air bubbles that may be generated during the filling of the internal space with the protective medium can be removed from the protective medium.

[0019] In one embodiment, the closure of the at least one membrane opening is performed by dispensing a preferred liquid monomer onto the membrane in a region of at least one membrane opening and then curing the monomer into a polymer. In one embodiment, the monomer dispensing, or output, is achieved using a thin sleeve. In another embodiment, the dispensing is performed by spray-coating, thereby enabling the formation of a thinner and more uniform layer. Curing can be performed under irradiation, such as ultraviolet light. Overall, this method can produce a thin and stable filler.

[0020] In one embodiment, the closure of at least one diaphragm opening is performed by dispensing a preferred liquid polymer onto a diaphragm in a region of at least one diaphragm opening and then curing the polymer. Different polymers, such as standard polymer adhesives, can be used. By using a polymer for closing at least one diaphragm opening, methods commonly used in semiconductor assembly can be considered. This simplifies sensor manufacturing.

[0021] In one embodiment, closure of at least one diaphragm opening is achieved in the presence of excess protective medium (Anwesenheit) on at least one diaphragm opening. In this way, it is not necessary to ensure that the diaphragm and / or diaphragm opening are free of excess protective medium. This simplifies the manufacturing process.

[0022] In one embodiment, excess protective medium present on the diaphragm is removed prior to the closure of at least one diaphragm opening. In this way, good adhesion of the sealing material and / or a wide variety of available sealing materials (palette) can be achieved.

[0023] In one embodiment, the diaphragm is fixed to an intermediate carrier, and when the diaphragm is fixed to or within a housing opening, the intermediate carrier is also fixed to or within the housing opening. This intermediate carrier (also called an insertion mechanism) simplifies the manufacturing of the sensor or the fixing of the diaphragm to or within the housing opening. For this purpose, the diaphragm is connected to the intermediate carrier in an upstream manufacturing step. Then, the intermediate carrier, together with the diaphragm, can be inserted into or fixed to the housing opening. This allows the manufacturing steps to be parallelized.

[0024] In one embodiment, the housing and the intermediate carrier and / or the intermediate carrier and the diaphragm are fixed to each other by a clamping connection and / or by mutual pressing. This allows for a particularly simple and stable fixation of the diaphragm within or on the housing opening and / or a media seal.

[0025] In one embodiment, the housing and intermediate carrier are fixed to each other by means of a material-locking connection process, preferably by welding. In this way, particularly high media sealing and / or particularly stable connection can be achieved.

[0026] In one embodiment, at least one diaphragm opening has an extension dimension of a few millimeters or less, preferably less than or equal to 1 millimeter, and particularly preferably less than or equal to 0.5 millimeters, wherein the at least one diaphragm opening has an extension dimension greater than 10 micrometers, preferably greater than or equal to 100 micrometers. A size of a few millimeters or less for one or more diaphragm openings allows for sufficiently large openings that have little or no impact on the stability of the diaphragm. A size of less than or equal to 0.5 millimeters for one or more diaphragm openings has less impact on the diaphragm, making it possible to simplify the manufacturing process up to closing the diaphragm opening. Such small diaphragm openings are particularly suitable when using multiple diaphragm openings. A size of more than 10 micrometers for one or more diaphragm openings allows for reliable handling during manufacturing. With a size greater than or equal to 100 micrometers, clogging of one or more diaphragm openings can be avoided, depending on the protective medium used.

[0027] In one embodiment, the protective medium is formed from an incompressible fluid, preferably oil. This allows for the provision of a protective medium in a simple manner.

[0028] Other important features and advantages of the present invention will become apparent from the description of preferred embodiments, the accompanying drawings, and the related drawings with reference to the figures. It will be understood that the features mentioned above and set forth below can be used not only in the combinations described separately, but also in other combinations or individually, without departing from the scope of the invention.

[0029] Preferred embodiments and implementations of the invention are shown in the accompanying drawings and described in detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components or elements. Attached Figure Description

[0030] This is shown here: Figure 1 A perspective view of an embodiment of the sensor according to this disclosure. Figure 2 according to Figure 1 Side view of the sensor. Figure 3 according to Figure 1 Top view of the sensor Figure 4 according to Figure 3 An oblique view of the cross section of the sensor along line A–A. Figure 5 according to Figure 3 A side view of the sensor along a section of line A–A. Figure 6 A flowchart illustrating an implementation of the method according to this disclosure. Detailed Implementation

[0031] Figures 1 to 5 Different views are shown illustrating embodiments of sensors manufactured according to the methods of this disclosure.

[0032] Figure 1 A perspective view of sensor 1 is shown. The housing 2 of sensor 1 is formed by a rewiring substrate 3 and a sleeve 4. A housing opening 5 is constructed in the upper region, into which an intermediate carrier 6 (also called an interposer) is pressed. The intermediate carrier 6 has an intermediate carrier opening 7 through which the filler 8 can be seen.

[0033] Figure 2 A side view of sensor 1 with a rewiring substrate 3 and a sleeve 4 is shown.

[0034] Figure 3 A top view of a sensor 1 having a redistribution substrate 3, a sleeve 4, an intermediate carrier 6, and a filler 8 is shown.

[0035] Figure 4 A perspective view showing a cross-section of sensor 1 is provided. An ASIC (Application Specific Integrated Circuit) 9 is disposed on a redistribution substrate 3, and a sensing element 10 is disposed on the ASIC 9. The sensing element 10 is disposed in an internal space 20 constructed within a housing 2. The internal space 20 is at least partially filled with a protective medium 11, which shields the sensing element 10 from the surrounding ambient medium 12 on one hand, and further transmits the characteristics and / or composition of the ambient medium to the sensing element 10 on the other hand, such as the pressure in the ambient ambient medium 12. An intermediate carrier 6 is disposed in a housing opening 5, and a diaphragm 13 is disposed on the underside of the intermediate carrier. The diaphragm 13 has a diaphragm opening 14, which has been closed by a filler 8. The intermediate carrier is pressed into a sleeve 4, thereby securing the diaphragm 13 in the housing opening 5.

[0036] exist Figure 5 These components can also be seen from slightly different angles.

[0037] Figure 6 A flowchart illustrating an embodiment of the method according to this disclosure is shown. In step S1, a sensor 1 having a sensing element 10 and a housing 2 is provided, wherein an internal space 20 is constructed in the housing 2, accessible through a housing opening 5, and the sensing element 10 is arranged within this internal space. Two alternatives are shown starting from step S1. In a first alternative, a protective medium 11 is first filled into the internal space 20 in step S2, and then a diaphragm 13 is fixed to or into the housing opening 5 in step S3. In a second alternative, the diaphragm 13 is first fixed in step S3, and then the protective medium 11 (e.g., through the diaphragm opening 14) is filled into the internal space 20 in step S2. The filling of the internal space 20 by means of the protective medium 11 can be achieved at atmospheric pressure. The diaphragm can be fixed by pressing an intermediate carrier into a sleeve 4 (by means of an optional material-locking connection); or by inserting an intermediate carrier 6, followed by a material-locking connection. The material-locking connection can here be performed by a welding process.

[0038] In an optional step S4, the protective medium 11 is degassed, for example, by applying negative pressure to the sensor. In another optional step S5, excess protective medium 11 located in the region of the diaphragm opening 14, particularly on the upper side of the diaphragm 13, is removed. In this way, a contact surface can be prepared for the filler 8 used to close the diaphragm opening 14. This excess protective medium 11 may be generated in both of the above-described sequences of steps S2 and S3. In step S6, the diaphragm opening is closed by the filler 8. In step S6, a liquid monomer can be applied to the region of the diaphragm opening and subsequently crosslinked (vernetzen) to form a polymer, for example, under ultraviolet light irradiation.

[0039] Although the invention has been described with reference to preferred embodiments, the invention is not limited thereto and can be modified in various ways.

Claims

1. A method for manufacturing a sensor, wherein, The sensor (1) has a sensing element (10) and a housing (2), wherein the housing (2) has an internal space (20) accessible through a housing opening (5), and wherein the sensing element (10) is arranged in the internal space (20) and configured to detect the properties and / or composition of the surrounding environmental medium (12) of the sensor (1), the method comprising: • A protective medium (11) is filled into the internal space (20) through the housing opening (5), wherein the protective medium (11) is configured to transmit the properties and / or composition of the surrounding environmental medium (12) to the sensing element (10). • The diaphragm (13) is fixed to or into the housing opening (5) to close the housing opening (5), wherein the diaphragm (13) has at least one diaphragm opening (14), and • Close at least one membrane opening (14).

2. The method according to claim 1, characterized in that, Before the closure of the at least one membrane opening (14), the protective medium (11) is degassed, wherein the degassed protective medium is performed by applying a negative pressure to the at least one membrane opening.

3. The method according to claim 1 or 2, characterized in that, The closure of the at least one membrane opening is performed by dispensing a monomer onto a membrane in the region of the at least one membrane opening, and then curing the monomer into a polymer.

4. The method according to claim 1 or 2, characterized in that, The closure of the at least one membrane opening (14) is performed by dispensing a polymer onto a membrane (13) in the region of the at least one membrane opening (14) and then curing the polymer.

5. The method according to claim 1 or 2, characterized in that, The at least one diaphragm opening (14) is closed in the presence of excess protective medium (11) present on the at least one diaphragm opening (14).

6. The method according to claim 1 or 2, characterized in that, Before the at least one membrane opening (14) is closed, excess protective medium (11) present on the membrane (13) is removed.

7. The method according to claim 1 or 2, characterized in that, The diaphragm (13) is fixed on the intermediate carrier (6), and the intermediate carrier (6) is fixed on the housing opening (5) or in the housing opening when the diaphragm (13) is fixed on the housing opening (5) or in the housing opening.

8. The method according to claim 7, characterized in that, The housing (2) and the intermediate carrier (6) and / or the intermediate carrier (6) and the diaphragm (13) are connected to each other by clamping and / or fixed to each other by mutual pressing.

9. The method according to claim 7, characterized in that, The shell (2) and the intermediate carrier (6) are fixed to each other by means of a material locking connection process.

10. The method according to claim 1, characterized in that, The diaphragm (13) is flexible.

11. The method according to claim 3, characterized in that, The monomer is in a liquid state.

12. The method according to claim 4, characterized in that, The polymer is liquid.

13. The method according to claim 9, wherein, The shell (2) and the intermediate carrier (6) are fixed together by welding.

14. A sensor manufactured by means of any one of claims 1 to 13.

15. The sensor according to claim 14, characterized in that, The at least one membrane opening (14) has an extension dimension of less than or equal to 1 mm, wherein the at least one membrane opening has an extension dimension of more than 10 micrometers.

16. The sensor according to claim 15, characterized in that, The at least one membrane opening has an extension dimension greater than or equal to 100 micrometers.

17. The sensor according to claim 15, characterized in that, The at least one diaphragm opening (14) has an extension dimension of less than or equal to 0.5 mm.

18. The sensor according to claim 14 or 17, characterized in that, The protective medium (11) is formed of an incompressible fluid.

19. The sensor according to claim 14, characterized in that, The sensor is a pressure sensor.

20. The sensor according to claim 18, characterized in that, The incompressible fluid is oil.

Images