Microelectromechanical sensor and method for producing microelectromechanical sensor

Abstract

The invention relates to a microelectromechanical sensor (1) having a sensor substrate (2) with a sensor structure (3) and a cover substrate (4), between which a first cavity region (5) is formed at least in the region of the sensor structure (3), the cover substrate (4) having at least one channel (6), the at least one channel (6) extends from a first side (7) of the cover base (4) through the cover base (4) into a first cavity region (5), the cover base (4) has a region (8) on the first side (7) adjacent to the channel (6), and at least the region (8) is provided with a hydrophobic surface coating (9). The invention further comprises a method (100) for manufacturing a microelectromechanical sensor.

Description

Field of the Invention

[0001] The present invention relates to a microelectromechanical sensor and a method for manufacturing a microelectromechanical sensor. Background Art

[0002] Microelectromechanical sensors and methods for manufacturing microelectromechanical sensors are known from the prior art.

[0003] DE 10 2017 200 714 A1 discloses a method for manufacturing a microelectromechanical inertial sensor.

[0004] The measurement of state variables (such as pressure) can be performed with the aid of microelectromechanical sensors. These sensors offer the following advantages: they react very sensitively to changes in the state in the environment and can also detect small changes in the state. In order to protect the microelectromechanical sensor and especially the sensor structure of the sensor from damage caused, for example, by particles and / or the influence of harmful media, a cover is used, for example. However, at least one channel through the cover needs to be provided when measuring a pressure change. Since the at least one channel can be, for example, a liquid medium can enter the interior of the sensor and thereby may affect the sensor structure and / or the measurement signal obtained with the sensor structure. Summary of the Invention

[0005] Accordingly, it is an object of the present invention to provide an improved microelectromechanical sensor and an improved method for manufacturing a microelectromechanical sensor. The sensor in particular has the following task: to have improved resistance to the influence of harmful media.

[0006] This object is solved by a micromechanical sensor according to claim 1 and by a method according to claim 9. Advantageous configurations are the subject matter of the dependent claims.

[0007] According to one aspect of the present invention, there is provided a microelectromechanical sensor having a sensor substrate, a sensor structure, and a cover substrate. A first cavity region is formed at least in the region of the sensor structure between the cover substrate and the sensor substrate. The cover substrate further has at least one channel passing through the cover substrate. At least one channel extends from a first side of the cover substrate facing away from the first cavity region into the first cavity region. The cover substrate has a region adjacent to the channel on the first side, wherein at least the region adjacent to the channel is provided with a hydrophobic surface coating.

[0008] This embodiment offers the following advantages: Due to the hydrophobic effect of the surface coating, liquids, especially water, cannot adhere to and / or roll into this area. Thereby, an improvement is achieved to prevent liquids from entering the first cavity area. That is, it can be advantageously achieved, especially to prevent damage and / or impairment of the sensor structure and / or the measurement signal caused by water in the first cavity area of the sensor. In addition, this embodiment shows a compact structure of the sensor and can be effectively implemented with low production costs.

[0009] In another embodiment, the area with the hydrophobic surface coating is at least partially directly adjacent to the channel, and / or the area with the hydrophobic surface coating at least sectionally surrounds the channel, and / or the area with the hydrophobic surface coating annularly surrounds the channel, and / or the area with the hydrophobic surface coating is implemented at a distance from the channel. This embodiment offers the following advantages: In the area of the channel, the geometric configuration of the area with the hydrophobic surface coating can be advantageously implemented in terms of the liquid-repelling property.

[0010] In another embodiment, the channel has at least one wall surface, wherein at least one wall surface of the channel is at least partially provided with a hydrophobic surface coating.

[0011] In another embodiment, the wall of the first cavity area and / or the surface of the sensor structure implemented, for example, in a cantilevered manner, at least partially has a hydrophobic surface coating. This embodiment offers the following advantages: The surface coating can additionally protect the cantilevered sensor structure from adhering to the sensor substrate surrounding the sensor structure.

[0012] In another embodiment, the channel passing through the cover substrate extends in the longitudinal direction from the first side of the cover substrate and has a first section and a second section. The first section has a first cross-section, while the second section has a second cross-section, wherein the second cross-section is larger than the first cross-section of the first section, wherein the first section with the first cross-section leads to the second section with the second cross-section in a full-periphery manner, and wherein the first and second cross-sections preferably have a common median perpendicular. This embodiment offers the following advantages: By different cross-sections, the capillary effect in the channel can be reduced or completely prevented.

[0013] In another embodiment, at least one channel has an opening on the first side of the cover substrate, wherein the opening has a minimum geometric dimension in at least one direction parallel to the first side of the cover substrate, and the minimum geometric dimension is preferably less than 50 μm and especially greater than 0.1 μm. This embodiment offers the following advantages: By appropriately selecting the geometric shape and / or size of the opening, it is preferably completely prevented that liquids enter the first cavity area, and at the same time, the opening can be selected to be large enough so that changes in the state from the environment can be transmitted to the sensor structure without major restrictions.

[0014] In another embodiment, the hydrophobic surface coating is configured as an anti-sticking layer, wherein the anti-sticking layer is in particular an organic anti-sticking layer. This provides the following advantage: the anti-sticking layer can be at least partially removed again after application by radiation (for example by VUV radiation). Particularly advantageously, the anti-sticking layer is first applied to the sensor over a large area.

[0015] In another embodiment, the anti-sticking layer has a silicone layer and / or a fluorine-containing layer, and / or the anti-sticking layer has a layer thickness, wherein the layer thickness is less than 10 μm.

[0016] The invention also includes a method for manufacturing a microelectromechanical sensor, wherein the method comprises the following steps:

[0017] - Providing a sensor substrate having a sensor structure;

[0018] - Fastening a cover substrate to the sensor substrate, wherein between the sensor substrate and the cover substrate, a first cavity region is formed at least in the region of the sensor structure, and wherein at least one channel is formed through the cover substrate, which channel extends from a first side of the cover substrate into the first cavity region;

[0019] - Applying a hydrophobic surface coating to the first side of the cover substrate at least in the region of the channel.

[0020] By the proposed method, the sensor can be manufactured in a simple and efficient manner using common semiconductor process steps. According to an expansion scheme, then, the hydrophobic surface coating can be applied to the first side of the cover substrate at least in the region of at least one channel. This can be used to prevent liquid from entering into at least one channel and into the first cavity.

[0021] In another embodiment, the hydrophobic surface coating is applied to the first side of the cover substrate at least locally directly adjacent to at least one channel, and / or the hydrophobic surface coating is applied to the first side of the cover substrate at least sectionally in a region outside at least one channel, and / or the hydrophobic surface coating is applied annularly to the first side of the cover substrate in a region surrounding at least one channel, and / or the hydrophobic surface coating is applied to the first side of the cover substrate spaced apart from the channel.

[0022] In another embodiment, the hydrophobic surface coating is applied at least partially on at least one wall surface of the channel and / or at least partially on the wall of the cavity region and / or at least partially on the surface of the sensor structure.

[0023] In another embodiment, the surface coating is applied by means of a CVD or ALD method. This provides the following advantage: the surface coating can be applied uniformly and as a particularly thin layer.

[0024] In another embodiment, the surface coating is locally removed after application, wherein radiation and a mask, preferably a reticle, are used. The mask is provided with a radiation-impermeable mask layer at least in the region of at least one channel.

[0025] In another embodiment, the radiation is performed at a wavelength of less than 390 nm, preferably less than 180 nm, wherein a fused silica mask is used as the mask. A chromium layer is used as the mask layer on the fused silica mask. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be explained in more detail below with reference to the drawings. Shown herein are:

[0027] - Figure 1 A schematic cross-sectional view of a sensor in an exemplary embodiment;

[0028] - Figure 2 A top view of a cover substrate and an exemplary first embodiment for channels and regions;

[0029] - Figure 3 A top view of a cover substrate and an exemplary second embodiment for channels and regions;

[0030] - Figure 4 A schematic cross-sectional view of a sensor in another embodiment;

[0031] - Figure 5 A schematic cross-sectional view of a sensor in another embodiment;

[0032] - Figure 6 A schematic cross-sectional view of the sensor during a method step;

[0033] - Figure 7 Another schematic cross-sectional view of the sensor;

[0034] - Figure 8 A schematic illustration of a method for manufacturing a sensor. DETAILED DESCRIPTION

[0035] Figure 1 A simplified schematic cross-sectional view of the sensor 1 in the first embodiment is shown.

[0036] The sensor 1 has a sensor substrate 2 with a sensor structure 3 and a cover substrate 4. The sensor 1 is a micro-electromechanical sensor 1 (MEMS sensor for short) and can be implemented as a pressure sensor, for example. For this purpose, the sensor structure 3 can be exemplarily configured as a cantilevered sensor structure 3. The configuration of the sensor structure 3 can be achieved, for example, by applying layers in a layer system 19 and optionally structuring the layers. Exemplarily, the sensor structure 3 has a second cavity region 20, a sensor element 24 and a sensor membrane 21. The sensor substrate 2 or the layer system 19 is connected to the cover substrate 4 in a connection region 23. For the connection in the connection region 23, a bonding frame, for example, can be used.

[0037] A first cavity region 5 is provided between the sensor substrate 2 and the cover substrate 4, at least in the region of the sensor structure 3. Further, at least one channel 6 is provided through the cover substrate 4. The channel 6 extends from the first side 7 of the cover substrate 4 facing away from the first cavity region 5 to the second side 22 of the cover substrate facing the first cavity region 5 and leads into the first cavity region 5. It is also conceivable that a plurality of channels 6 are provided through the cover structure 4. At least one channel 6 has an opening 15 on the first side 7 of the cover substrate 4 and has at least one wall 10. The opening 15 of the channel 6 can have different shapes and can be implemented, for example, circularly, quadrilaterally, polygonally, triangularly, elliptically or star-shaped and optionally with rounded corners. If a plurality of channels 6 are provided through the cover substrate 4, their openings 15 can be implemented identically or can have different geometric shapes and / or different geometric dimensions. The channel 6 is preferably used to transmit a state change from the environment to the first cavity region 5. The state change from the environment can be, for example, a pressure change. The pressure change transmitted through the channel 6 into the first chamber region 5 can contribute to a change in the deflection of the sensor membrane 21 of the pressure-measuring sensor element 24 .

[0038] The cover substrate 4 is preferably used to protect the sensor structure 3 from external environmental influences. The cover substrate 4 can be used, for example, to protect the sensor structure 3 from coarse dirt and / or particles. An opening 15 of the channel 6 is provided on the first side 7 of the cover substrate 4. Further, the cover substrate 4 has a region 8 on the first side 7 adjacent to the channel 6 or the opening 15 of the channel 6. The region 8 can, for example, be directly adjacent to the channel 6. The region 8 can also surround the channel 6 sectionally. It is also conceivable that the region 8 surrounds the channel annularly. In addition, the region 8 can also be implemented at a distance from the channel 6. The region 8 is provided with a hydrophobic surface coating 9. The hydrophobic surface coating 9 is used to let the liquid roll from the surface of the cover substrate 4 into the region 8. Thereby, it is advantageously achieved that the liquid cannot enter the first cavity region 5 and / or reach the sensor structure 3. In addition, the opening 15 of at least one channel 6 has at least one minimum geometric dimension in a direction parallel to the first side 7 of the cover substrate 4, wherein the minimum geometric dimension is preferably less than 50 μm, particularly preferably less than 20 μm and especially greater than 0.1 μm. By the geometric configuration of the opening 15 of at least one channel 6, it is additionally possible to make it difficult for the liquid to enter the sensor interior.

[0039] The hydrophobic surface coating 9 can, for example, be configured as an anti-sticking layer and especially as an organic anti-sticking layer. It is conceivable that the anti-sticking layer has a silicone layer and / or a fluorine-containing layer. Preferably, the anti-sticking layer can be applied by CVD or ALD methods, wherein the anti-sticking layer preferably has a layer thickness 25 of less than 10 μm. As already mentioned, the opening 15 of the channel 6 and / or the region 8 having the hydrophobic surface coating 9 can have different geometric shapes on the first side 7 of the cover substrate 4. Some embodiments are described below in Figure 2 and Figure 3 Some embodiments are described below in

[0040] Figure 2 shows a top view of the cover substrate 4 and an exemplary first embodiment for the channel 6 and the region 8.

[0041] On a first side of the cover substrate 4, the channel 6 is provided with an opening 15, and the region 8 is provided with a hydrophobic surface coating 9. In this embodiment, the opening 15 of the channel 6 is exemplarily circularly arranged. It is also conceivable that the opening 15 of the channel 6 can have other geometric embodiments and can be implemented, for example, star-shaped, elliptical, quadrangular or polygonal and optionally with rounded corners. In this example, the region 8 with the hydrophobic surface coating 9 is implemented quadrangularly and spaced apart from the opening 15 of the channel 6 and exemplarily has two regions in which there is no hydrophobic surface coating 9 and which divide the region 8 into two halves. The region 8 can also be implemented as a completely closed surface. Similarly, the region 8 can have different geometric shapes. Further, it can also be implemented circularly, star-shaped, elliptical or polygonal and can optionally be implemented with rounded corners. Further, the region 8 can be implemented at least sectionally at a distance from the channel 6. However, the region 8 can also be directly adjacent to the channel 6 over its entire circumference. Alternatively, the opening 15 and / or the channel 6 and / or the region 8 can have the same or different geometric embodiments.

[0042] Figure 3 A top view of the cover substrate 4 and an exemplary second embodiment for the channel 6 and the region 8 are shown.

[0043] The cover substrate 4 again has a region 8 with a hydrophobic surface coating 9 and a channel 6 with an opening 15. In this embodiment, exemplarily, the opening 15 of the channel 6 is shown elliptically. In this embodiment, the region 8 is directly adjacent to the opening 15 of the channel 6. In addition, the region 8 is implemented circularly and over its entire area and completely surrounds the channel 6. As shown in this example and in the example from Figure 2 it can be seen that not only the channel 6 with its opening 15 but also the region 8 with the hydrophobic surface coating 9 can be implemented in very different geometric variants.

[0044] Figure 4 A schematic cross-sectional view of the sensor 1 in another embodiment is shown.

[0045] The sensor 1 is mostly similar to Figure 1The sensor 1 is constructed as a pressure sensor. Exemplarily, the sensor 1 can be implemented as a pressure sensor. Here, the sensor 1 has a cover substrate 4, a sensor substrate 2 and a sensor structure 3. The sensor structure 3 has a sensor element 24 and a sensor membrane 21. The sensor structure 3 is implemented as a cantilevered sensor structure 3. The sensor substrate 2 is connected to the cover substrate 4 in the connection area 23. The cover substrate 4 has a channel 6 passing through the cover substrate 4, which extends from the first side 7 of the cover substrate 4 away from the cavity area 5 to the second side 22 of the cover substrate 4 facing the cavity area 5 and leads to the first cavity area 5. On the first side 7, an area 8 is arranged. The area 8 is provided with a hydrophobic surface coating 9. In this embodiment, the channel 6 has a first section 11 and a second section 12 starting from the first side 7 of the cover substrate 4 in a direction perpendicular to the first side 7 of the cover substrate 4. The first section 11 has a first cross section 13, and the second section 12 has a second cross section 14, wherein the surface parallel to the first side 7 of the cover substrate can be regarded as a cross section. Preferably, the first cross section 13 is selected to be smaller than the second cross section 14, wherein the first section 11 with the first cross section 13 leads to the second section 12 with the second cross section 14 all around, wherein the first and second cross sections 13, 14 preferably have a common middle vertical line. Thus, it is possible to additionally make it difficult to form a capillary effect in the channel 6 and to allow the liquid to enter the first chamber area 5. In this embodiment, at least one wall 10 of the channel 6 is provided with a hydrophobic surface coating 9. It is also conceivable that at least one wall 10 is only partially provided with a hydrophobic surface coating 9. In this embodiment, the wall 27 of the first chamber area 5 and the surface 28 of the sensor structure 3 are at least partially provided with a hydrophobic surface coating 9. The hydrophobic surface coating 9 can, for example, be implemented as an anti-adhesive layer. The application of the anti-adhesive layer can be achieved by different methods. For example, the anti-adhesive layer can be applied by CVD or ALD methods, wherein the layer thickness of the anti-adhesive layer is preferably set less than 10 μm. In this embodiment, the anti-adhesive layer can also advantageously prevent the cantilevered sensor structure 3 from adhering to the sensor substrate 2 surrounding the sensor structure 3.

[0046] Figure 5 A schematic sectional view of a sensor 1 is shown in another embodiment.

[0047] The construction of sensor 1 is largely similar to that of Figure 4The sensor 1 described in the specification. The sensor 1 has a sensor substrate 2 with a sensor structure 3. For example, the sensor structure 3 is configured as a pressure sensor. The sensor 1 has a cover substrate 4 and a first cavity area 5. The cover substrate 4 has a channel 6 passing through the cover substrate 4. The channel 6 has a first section 11 and a second section 12. The channel 6 extends from a first side 7 of the cover substrate 4 facing away from the cavity area 5 into the first cavity area 5. An area 8 is arranged adjacent to the channel 6. In this embodiment, except for the area 8, the first side 7 of the cover substrate 4 and all surfaces of the sensor 1 that are freely accessible during the deposition of the surface coating 9 are completely provided with a hydrophobic surface coating 9. In addition, the walls of the first and second sections 11, 12 of the channel 6, the wall 27 of the first cavity area 5 and the surface 28 of the sensor structure 3 are at least partially provided with a hydrophobic surface coating 9. In addition, the hydrophobic surface coating 9 can be applied to the surface of the sensor substrate 2 in an opening through the cover substrate 4 outside the first cavity area 5. In order to improve the representability of the opening through the cover substrate 4 outside the first cavity area 5, in the attached Figure 1 , 4, 5, 6, 7. The interruption 29 is intended to be able to additionally indicate, for example, a bonding pad area 30 that is remote from the sensor structure 3. By way of example, here too, the sensor substrate 2 and the bonding pads 31 located thereon are provided with a hydrophobic surface coating 9. The sensor substrate 2 and the cover substrate 4 are connected at the connection area 23. The hydrophobic surface coating 9 can in turn be designed as an anti-adhesive layer and can be applied, for example, using a CVD or ALD method.

[0048] Figure 6 A schematic cross-sectional view of sensor 1 is shown during a method step.

[0049] The construction of sensor 1 is similar to that in Figure 5 After the hydrophobic surface coating 9 has been applied, it is advantageous to partially remove the hydrophobic surface coating 9, which can be done in this case by Figure 6The method steps shown in are implemented. Here, the sensor 1 is placed in a processing chamber in an oxygen-containing atmosphere and is placed under a mask 17 when the chamber pressure is limited. The mask 17 can be a quartz glass mask in particular. In an oxygen-containing atmosphere, the surface coating 9 can be removed by using radiation 16. The region 8 can be protected from radiation by means of a mask layer 18 that is impermeable to radiation. For example, a chromium layer can be used as the mask layer 18. The chromium layer is exemplarily arranged on the side of the quartz glass mask 17 facing the sensor 1 and covers at least the region 8. It is achieved that the region 8, the channel 6, the first cavity region 5 and the sensor structure 3 are protected from the radiation 16. For example, VUV radiation is used for the radiation 16. Preferably, the wavelength of the VUV radiation is selected so that it can destroy the CC bond (carbon bond) and generate oxygen free radicals and / or ozone. Preferably, the VUV radiation has a wavelength of less than 390nm, particularly preferably less than 180nm. Advantageously, by using the mask 17 and the masking layer 18 arranged therein, the hydrophobic surface coating 9 can be removed only at defined locations.

[0050] Figure 7 A further schematic sectional view of the sensor 1 is shown.

[0051] Sensor 1 is similar to the Figure 4 The sensor 1 is constructed in the manner of a sensor structure 1. The sensor 1 has a sensor substrate 2, a sensor element 3 and a cover substrate 4. The sensor 1 is exemplarily implemented as a pressure sensor. The cover substrate 4 is connected to the sensor substrate 2 in a connection area 23. A first cavity area 5 is constructed between the cover substrate 4 and the sensor substrate 2, at least in the area of ​​the sensor element 3. The cover substrate 4 has a channel 6 passing through the cover substrate 4. On a first side 7 of the cover substrate 4, an area 8 with a hydrophobic surface coating 9 is arranged adjacent to the channel 6. Further, the hydrophobic surface coating 9 is at least partially arranged on at least one wall 10 of the channel 6, on a wall 27 of the first cavity area 5 and on a surface 28 of the sensor structure 3. Further, a droplet 26, such as a water droplet, is shown in the area 8 on the first side 7 of the cover substrate 4 by way of example. Due to the hydrophobic effect of the surface coating 9, the water droplet has the characteristic of constructing a large contact angle or edge angle on the surface coating 9 and rolls onto the area 8 due to the small contact surface formed on the hydrophobic surface coating 9.

[0052] By reducing the wettability of the surface, the spreading of liquids (such as, for example, water) on the surface can be reduced and capillary effects in narrow channels (tubes) and / or gaps can be reduced or completely avoided. By providing a hydrophobic surface coating 9 at least in the region 8 and by appropriately selecting the geometry and / or geometric dimensions of the opening 15 of the channel 6 and / or the region 8 with the hydrophobic surface coating 9, it can be achieved that, for example, no water can pass through the channel 6 into the first chamber region 5.

[0053] Figure 8 A schematic view showing a method 100 for manufacturing a sensor is presented.

[0054] In method step 110, a sensor substrate having a sensor structure is provided.

[0055] In method step 120, a cover substrate is fastened to the sensor substrate, wherein a cavity region is formed at least in the region of the sensor structure between the sensor substrate and the cover substrate, and wherein the cover substrate has at least one channel that extends from a first side of the cover substrate through the cover substrate into the cavity region.

[0056] In method step 130, a hydrophobic surface coating is applied to the first side of the cover substrate and at least in the region of the channel. Additionally, the hydrophobic surface coating can be applied to the sensor substrate in the region of the bonding pad opening in the cover substrate. The hydrophobic surface coating can be applied at least locally directly adjacent to the channel and on the first side of the cover substrate, or the hydrophobic surface coating can be applied at least sectionally to the region around the channel, or the hydrophobic surface coating can be applied annularly around the channel and / or the hydrophobic surface coating can be applied spaced apart from the channel. It is also conceivable that the hydrophobic surface coating is applied at least partially to at least one wall surface of the channel. Additionally, the hydrophobic surface coating can also be applied at least locally to the wall of the first cavity region. There is also the possibility that the hydrophobic surface coating is applied at least locally to the surface of the sensor structure. The hydrophobic surface coating can be applied, for example, by means of CVD or ALD methods.

[0057] Furthermore, method 100 can include another method step 140. Method step 140 is optional. In step 140, the hydrophobic surface coating is locally removed again after application. For this purpose, for example, radiation and a mask can be used. The radiation is preferably performed in an oxygen-containing environment and preferably using a wavelength of less than 390 nm, particularly preferably less than 180 nm.

[0058] It should be understood that method steps 110, 120, 130 can be implemented in any order.

[0059] Although the present invention has been illustrated based on specific embodiments above, those skilled in the art can also implement unpublicized or only partially disclosed embodiments without departing from the core of the present invention.

Claims

1. A microelectromechanical sensor (1) comprising a sensor substrate (2) with a sensor structure (3) and a cover substrate (4), wherein: A first cavity region (5) is constructed between the cover substrate (4) and the sensor substrate (2), at least in the region of the sensor structure (3), wherein the cover substrate (4) has at least one channel (6), wherein the at least one channel (6) extends from a first side (7) of the cover substrate (4) through the cover substrate (4) into the first cavity region (5), wherein the cover substrate (4) has a region (8) on the first side (7) adjacent to the channel (6), wherein at least the region (8) is provided with a hydrophobic surface coating (9).

2. The sensor (1) according to claim 1, wherein: The region (8) having the hydrophobic surface coating (9) is at least partially directly adjacent to the channel (6), and / or, the region (8) having the hydrophobic surface coating (9) is arranged spaced apart from the channel (6), and / or, the region (8) having the hydrophobic surface coating (9) at least partially surrounds the channel (6), and / or, the region (8) having the hydrophobic surface coating (9) surrounds the channel (6) in an annular manner.

3. The sensor (1) according to any one of the preceding claims, wherein: The channel (6) has at least one wall surface (10), wherein the at least one wall surface (10) of the channel (6) is at least partially provided with a hydrophobic surface coating (9).

4. The sensor (1) according to any one of the preceding claims, wherein: The wall (27) of the first chamber region (5) and / or the surface (28) of the sensor structure (3) at least partially has a hydrophobic surface coating (9).

5. The sensor (1) according to any one of the preceding claims, wherein: The channel (6) passing through the cover substrate (4) extends in the longitudinal direction from the first side (7) of the cover substrate (4) and has a first section (11) and a second section (12), wherein the first section (11) has a first cross-section (13) and the second section (12) has a second cross-section (14), wherein the second cross-section (14) is larger than the first cross-section (13) of the first section (11), wherein the first section (11) having the first cross-section (13) leads to the second section (12) having the second cross-section (14) over the entire circumference, wherein the first cross-section (13) and the second cross-section (14) preferably have a common center vertical line.

6. The sensor (1) according to any one of the preceding claims, wherein: The channel (6) has an opening (15) on the first side (7) of the cover substrate (4), wherein the opening (15) preferably has at least one minimum geometric dimension in a direction parallel to the first side (7) of the cover substrate (4), which is smaller than 50 μm and in particular larger than 0.1 μm.

7. The sensor (1) according to any one of the preceding claims, wherein: The hydrophobic surface coating (9) is designed as an anti-adhesive layer, wherein the anti-adhesive layer is in particular an organic anti-adhesive layer.

8. The sensor (1) according to claim 7, wherein: The release layer comprises a silicone layer and / or a fluorine-containing layer, and / or wherein the release layer has a layer thickness, wherein the layer thickness is less than 10 μm.

9. A method (100) for manufacturing a micro-electromechanical sensor (1), the method comprising the following steps: - providing (110) a sensor substrate (2) having a sensor structure (3); - fastening (120) a cover substrate (4) to the sensor substrate (2), wherein: A first cavity region (5) is formed between the sensor substrate (2) and the cover substrate (4), at least in the region of the sensor structure (3), wherein the cover substrate (4) has at least one channel (6) which extends from a first side (7) of the cover substrate (4) through the cover substrate (4) into the first cavity region (5); A hydrophobic surface coating (9) is applied (130) to the first side (7) of the cover substrate (4), at least in the region (8) of the channel (6).

10. The method (100) according to claim 9, wherein: The hydrophobic surface coating (9) is applied to the first side (7) directly adjacent to the channel (6), and / or, the hydrophobic surface coating (9) is applied to the first side (7) at a distance from the channel (6), and / or, the hydrophobic surface coating (9) is applied at least in sections in a region surrounding the channel (6), and / or, the hydrophobic surface coating (9) is applied in an annular manner around the channel (6).

11. The method (100) according to any one of claims 9 or 10, wherein: The hydrophobic surface coating (9) is at least partially applied to at least one wall (10) of the channel (6), and / or, wherein the hydrophobic surface coating (9) is at least partially applied to a wall (27) of the first cavity area (5), and / or, wherein the hydrophobic surface coating (9) is at least partially applied to a surface (28) of the sensor structure (3).

12. The method (100) according to any one of claims 9 to 11, wherein: The surface coating (9) is applied by means of a CVD or ALD method.

13. The method (100) according to any one of claims 9 to 12, wherein: After application (130), the surface coating (9) is again locally removed, wherein radiation (16) and a mask (17) are used for the removal (140), wherein the mask (17) in the region (8) of the channel (6) is provided with a mask layer (18).

14. The method (100) according to claim 13, wherein: The irradiation (16) is carried out at a wavelength of less than 390 nm, preferably less than 180 nm, wherein a quartz glass mask is used as the mask (17), wherein a chromium layer is used as the mask layer (18) for the at least one channel (6).

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