Integrated sensor device

Abstract

The invention relates to an integrated sensor device. According to an embodiment, a sensor device includes a chip carrier, a semiconductor chip mounted on the chip carrier, and an electrical connection between a connection surface of the semiconductor chip and a corresponding connection surface of the chip carrier. The sensor device also includes a sensor chip having a sensor element arranged on the semiconductor chip. The sensor chip has a trench which mechanically decouples the sensor element from the remaining sensor chip. The chip housing forms a molding compound which at least partially encapsulates the semiconductor chip and the electrical connection and which has an opening in the region of the sensor element such that the sensor element can interact with a medium surrounding the sensor device. The molding compound covers the semiconductor chip up to the sensor chip.

Description

Technical Field

[0001] The present invention relates to the field of integrated sensors. Background Art

[0002] Nowadays, many sensor devices are designed as so-called system-in-package (SiP), i.e., they have one or more chips in a chip housing, in which sensor elements and further electronic circuits are integrated. Many integrated sensors are so-called smart sensors, which, in addition to the sensor element (which is sensitive to certain environmental parameters, such as pressure, temperature, carbon monoxide, etc.), also contain further electronic circuits, which, for example, process the sensor signal (e.g., amplify, digitize, filter, etc.) and can communicate with other electronic units if necessary.

[0003] Different concepts for producing integrated sensors are known per se. An example is a micromechanical structure integrated into silicon, a so-called MEMS (micro-electromechanical system). Other examples are sensor elements produced with the aid of SOI (silicon on insulator) or SOS (silicon on sapphire) technology, which contain, for example, piezoresistive elements. SiC (silicon carbide)-based SiCOI (SiC on insulator) technology is also known for producing integrated sensor elements for pressure measurement. In the following, a sensor element integrated into a chip is referred to as a sensor chip.

[0004] MEMS sensors can be designed, for example, for multiple sensor applications. There are MEMS sensors for measuring pressure (in a gas environment), measuring air quality, detecting different chemical elements, etc. The properties of the medium surrounding the sensor are then referred to as environmental parameters. In order to be able to measure environmental parameters, the sensor element must be in physical contact with the medium surrounding the sensor element. This means that the sensor chip cannot be completely encapsulated in a casting compound like other integrated circuits (ICs), but must contain openings that allow the sensor element to be in physical contact with the surrounding medium (usually gas). Therefore, the packaging of the integrated sensor device must meet different requirements from conventional semiconductor chip packaging. Especially in MEMS, there is a risk of introducing mechanical stress into the sensor chip, which may have a negative impact on the performance of the sensor chip. Summary of the invention

[0005] The object of the present invention is to improve the production, in particular the packaging, of integrated sensor arrangements.

[0006] The stated object is achieved by a sensor device according to claim 1 and a method according to claim 12. Various embodiments and developments are the subject matter of the dependent claims.

[0007] A sensor device and a method for manufacturing the same are subsequently described. According to an embodiment, the sensor device comprises a chip carrier, a semiconductor chip mounted on the chip carrier, and an electrical connection between a connection surface of the semiconductor chip and a corresponding connection surface of the chip carrier. The sensor device also comprises a sensor chip having a sensor element arranged on the semiconductor chip. The sensor chip has a groove that mechanically decouples the sensor element from the rest of the sensor chip. The chip housing forms a molding compound that at least partially encapsulates the semiconductor chip and the electrical connection and has an opening in the region of the sensor element so that the sensor element can interact with a medium surrounding the sensor device. The molding compound covers the semiconductor chip up to the sensor chip.

[0008] According to an embodiment, the method comprises providing a wafer with a plurality of semiconductor chips, and bonding a plurality of sensor chips to respective semiconductor chips, wherein the sensor chips each have a sensor element and a trench, which mechanically decouples the sensor element from the remaining sensor chips. The method further comprises singulating the semiconductor chips together with the sensor chips arranged thereon, mounting the semiconductor chips on respective chip carriers, and (subsequently) encapsulating the semiconductor chips with a molding compound, wherein openings in the molding compound remain free in the region of the sensor elements of the sensor chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Subsequently, the embodiments are explained in detail with the aid of the drawings. These illustrations are not necessarily to scale, and the embodiments are not limited only to the aspects shown. Instead, the focus is on illustrating the principles on which the embodiments are based. In the drawings:

[0010] Figure 1 An example of a conventional integrated sensor device is shown, in which a sensor chip is arranged on another semiconductor chip in a chip-on-chip manner.

[0011] Figure 2 An example of a novel sensor device is shown, in which a sensor chip is arranged on a further semiconductor chip as a chip-on-chip, wherein the two chips are electrically connected by means of conductor tracks (strip conductors) instead of bonding wires,

[0012] Figure 3 Figures (a) to (d) show Figure 2 The different intermediate steps in the manufacture of a chip-on-chip arrangement,

[0013] Figure 4 Figures (a) to (d) show Figure 3 The different intermediate steps of the packaging process of chip-on-chip placement,

[0014] Figure 5 and Figure 6 Shows Figure 2 Two alternative embodiments of the example,

[0015] Figures 7 to 9 Further alternative embodiments are shown. DETAILED DESCRIPTION

[0016] Figure 1 An example of a conventional integrated sensor device 1 is shown, wherein a sensor chip 20 is arranged on another chip 10 in a chip-on-chip (CoC). The chip 10 is, for example, a semiconductor chip based on silicon and is mounted on a chip carrier 30 in a known manner. A lead frame is usually used as a chip carrier. In a particular embodiment, the chip carrier 30 can also be a multilayer substrate. Other types of chip carriers can also be used depending on the application. Chip-on-chip technology is a technology known per se, with which one chip is directly mounted on another chip. Therefore, chip-on-chip technology differs from other concepts, such as two or more chips are mounted side by side on a lead frame.

[0017] The sensor chip 20 has a sensor element 21 on the chip surface on the upper side, and the sensor element is configured to interact with the medium (e.g., gas) surrounding the chip and thereby measure the properties of the medium (e.g., physical or chemical parameters). That is, the sensor element 21 shows a signal containing information about the searched properties. In many applications, the sensor element 21 can be a microelectromechanical system (MEMS). MEMS is known as a sensor element itself and is therefore not explained in detail here. With the help of MEMS, for example, parameters such as the (static) pressure of the surrounding medium can be measured. Other MEMS sensor elements can, for example, measure the presence or concentration of sound pressure or substances (such as ozone, carbon monoxide, nitrogen dioxide, ammonia, etc.). The surface of the lower side of the sensor chip 20 is fully fixedly connected to the chip 10 below (e.g., by welding or pasting). The electrical connection between the sensor chip 20 and the chip 10 below is provided by a bonding wire 22. The related concept is called chip-to-chip bonding. The bonding wire connects the corresponding contact surfaces (bonding pads) on the surface of the sensor chip 20 or the chip 10 below.

[0018] The semiconductor chip 10 is connected to the chip contacts (e.g., pins, solder balls, etc.) of the lead frame 30 by means of bonding wires 12. The chip 10 is encapsulated by means of a casting compound 31 (molding compound) during the molding process. After curing, the casting compound 31 forms a chip package, which, however, only partially surrounds the chip 10 for sensor applications. The casting compound 31 (chip package) has an opening (cavity) in the area where the sensor chip 20 is located. It should be noted in this case that in manufacturing, the chip 10 is first mounted on the lead frame 30 (by means of a relatively soft adhesive layer 12), and then an electrical connection (bonding wire 12) between the chip 10 and the lead frame is established by means of wire bonding, and then a chip package 31 with a cavity is manufactured. For example, the chip package is manufactured by means of film assisted molding (FAM). FAM and other suitable molding processes are known per se and are therefore not described in detail here.

[0019] Only after the chip housing is manufactured, the sensor chip 20 is mounted in the cavity on the semiconductor chip 10 below and electrically contacted by means of bonding wires 22. Depending on the application, the cavity can thus remain open or be filled with gel 32. For example, in a pressure sensor, the sensor element is usually covered with a soft casting material, such as gel (silicone). This soft casting material must be soft enough even after curing so that the ambient pressure can be transmitted to the sensor element 21. The purpose of filling the cavity with a soft casting material is to protect the chip below from (dirt) particles and corrosion. In a chemical sensor (gas sensor) that detects the presence of a specific gaseous substance (such as carbon monoxide), of course, the cavity cannot be covered. A suitable soft casting material is very different from a molding material (such as epoxy resin) that is used to manufacture a chip housing and is fully cured (on the contrary, a soft casting material, such as silicone, remains soft).

[0020] The manufacture of the sensor device 1 is relatively complex, and the chip-to-chip bonding (after the manufacture of the chip housing) and the individual wire bonding of the sensor chip in particular increase the overall cost of the sensor device. As explained below, Figure 2 The embodiment shown can be manufactured more simply and more efficiently. The mounting of the sensor chip 20 onto the underlying semiconductor chip 10 does not take place here at the end of the manufacturing process (after the molding process for producing the housing) as in the previous example, but rather already in advance by means of chip-to-wafer bonding before the wafer is singulated into a plurality of semiconductor chips 10. Before discussing the manufacturing process in more detail, the following will describe the mounting of the sensor chip 20 onto the underlying semiconductor chip 10. Figure 2 The resulting sensor device 2 is described.

[0021] according to Figure 2, the sensor device 2 comprises a semiconductor chip 10 and a sensor chip 20 mounted thereon. The lower side of the sensor chip 20 can be fully connected to the surface of the chip 10 (for example, by gluing, welding, etc.). Unlike the previous example, the upper side of the sensor chip 20 is not electrically connected to the chip 10 below by means of bonding wires but by means of conductor lines 23, which also extend over the edges and narrow sides of the sensor chip 20. These conductor lines 23 (also called strip lines) can be manufactured by means of printing methods or electrochemical deposition (electroplating technology). Suitable methods for manufacturing strip conductors on different surfaces are known per se and are therefore not described further here. As mentioned, the installation of the sensor chip 20 and the manufacture of the strip conductors 23 can be carried out on the wafer plane, that is, as long as the wafer is still in one piece and before the wafer is singulated into a plurality of semiconductor chips 10. After the installation and the manufacture of the strip conductors 23, these strip conductors and optionally also a part of the sensor chip 20 (or the entire sensor chip) can be covered by a protective layer 24.

[0022] For example, a gel (gel casting) can be applied as protective layer 24. However, other protective layers for protection against particles or other harmful environmental influences are also known. Depending on the application of protective layer 24, sensitive parts of the sensor element can be left free.

[0023] After singulation, the semiconductor chip 10 and the sensor chip 20 mounted thereon are mounted on a lead frame 30. The chip 10 is electrically connected to the chip contacts (e.g., pins, solder balls, etc.) of the lead frame 30 by means of bonding wires 12 in a conventional manner. Subsequently, the chip 10 (including the bonding wires 12 and a portion of the strip conductor) is encapsulated using a casting compound 31 (molding compound) that forms a chip housing. In this case, the housing 31 also has an opening / cavity so that the sensor element 21 on the surface of the sensor chip 20 can interact with the medium surrounding the device. In this example, the housing 31 can also be manufactured using a FAM process known per se.

[0024] By abandoning the bonding wire (in Figure 1 The integrated sensor can be constructed more compactly (indicated by 22 in FIG. 1 ). The opening can be arranged relative to the sensor chip 20, and the distance between the sensor chip 22 and the molding compound 31 can be very small, that is, the molding compound 31 can extend to the side edge of the sensor chip 20. The chip housing can also be designed more compactly in the vertical direction, because the strip lines require significantly less space compared to the pull of the bonding wires.

[0025] and Figure 1 Compared to the first example, Figure 2In the example in , no soft potting compound, such as silicone, is needed to protect the bonding wires. Instead, the dielectric protection layer 24 protects the strip lines 23 which can already be applied to the wafer before chip singulation (eg by means of a mask produced by photolithography).

[0026] The use of strip lines 23 instead of bonding wires and the replacement of the soft potting compound by a (significantly harder) dielectric protective layer 24 also leads to disadvantageous effects which at first glance appear to be Figure 2 The suitability of the concept shown for manufacturing integrated sensors appears to be questionable (if not impossible). Through processes performed after mounting the sensor chip 20 on a wafer (e.g. application of the layer 24, chip singulation, molding process, etc.), residual stresses are introduced into the sensor chip 20, which have a negative impact on the performance of the sensor chip 20. This applies in particular to MEMS sensors. In addition, in accordance with Figure 2 In the example of FIG. 1 , the sensor chip 20 can be fixedly mounted on the chip 10 in a conventional manner (by means of a standard process for chip-on-chip mounting), whereas in FIG. Figure 1 In the example of FIG. 4 , the sensor chip 20 is mounted on the underlying chip 10 using a relatively soft adhesive in order to avoid introducing the above-mentioned residual stress.

[0027] exist Figure 1 In the example of FIG. 1 , low-stress mounting of the sensor chip 20 is ensured by a soft adhesive 12 , the use of flexible bonding wires and embedding the sensor chip in relatively soft silicone. Figure 2 An alternative approach is to provide stress relief in the chip plane or wafer plane for the sensor. Figure 2 2 is shown in the detail view indicated by an "X" in FIG. In this detail view, it can be seen that the sensor element 21 contained in the sensor chip 20 is surrounded by so-called trenches 25. These trenches 25 lead to the greatest possible mechanical decoupling of the (eg MEMS) sensor element 21 and the rest of the sensor chip 20.

[0028] The stress decoupling grooves 25 firstly enable the proper application of the strip conductors 23 for contacting the sensor chip 20, using standard processes for chip-on-chip mounting, and removing the soft casting compound 32. By exposing the MEMS membrane directly to the environment (without the layer consisting of silicone / gel / soft casting compound), the performance of the sensor is improved overall. This is possible because corrosion resistance is ensured by using a strip conductor protected by a dielectric layer 24. The exposure of the membrane is achieved in a simple manner by a FAM molding process. As in Figure 1 A larger opening in the chip housing as in the example of is not necessary.

[0029] Figure 3 Figures (a) to (d) show the Figure 2 Different intermediate steps in the on-chip chip layout. Figure 3 The diagram (a) in FIG. 1 shows a wafer 100 (before singulation) having a plurality of semiconductor chips 10. These semiconductor chips each have a contact surface 101 (contact pad) for connecting the corresponding chip 10 to the sensor chip 20 and a contact surface 102 (see FIG. 1 ) for connecting the corresponding chip 10 to the lead frame. Figure 4 ). The semiconductor chip 10 may be, for example, an application specific integrated circuit (ASIC), which is specifically designed for use with a particular sensor chip. For example, the semiconductor chip may contain digital electronics for processing sensor signals provided by the corresponding sensor chip 20 and for digital communication with other circuits, control units, etc. The semiconductor chip 10 (in combination with the sensor chip 20) may be considered a system on a chip.

[0030] In a next step, a plurality of sensor chips 20 are bonded to the corresponding semiconductor chips 10 of the wafer 100. Suitable chip-to-wafer bonding techniques (also referred to as bare die bonding) are known per se. For example, the sensor chips 20 (bare die) can be bonded to the underlying semiconductor chip by gluing, soldering or thermosonic bonding. Figure 3 The result of the die bonding process is shown in Figure (b). Figure 3 , Graph (b) shows the contact surfaces 26 on the upper side (next to the sensor element 21) of the sensor chip 20. In the next step, these contact surfaces 26 are electrically connected to the corresponding contact surfaces 101 of the semiconductor chip 10. The above-mentioned stress decoupling trenches 25 next to the sensor element 21 (MEMS) of the sensor chip 20 are also shown.

[0031] Figure 3 1 shows the wafer and the sensor chips 20 arranged thereon after the production of conductor tracks 23 (strip lines) in order to contact the sensor chips 20 with the corresponding semiconductor chips 10 of the wafer 100, wherein the strip lines 23 extend over the edges of the sensor chips 20. In the example shown, the strip lines 23 extend from the contact surface 26 over the edge of the corresponding sensor chip 20 (and therefore also over the adjacent narrow side of the sensor chip) to the corresponding contact surface 101 of the underlying semiconductor chip 10.

[0032] After the strip lines 23 have been produced, they can be covered with a dielectric protective layer 24 in order to protect the strip lines 23 from harmful environmental influences. A dielectric layer can also be arranged between the sensor chip 20 and the strip lines 23 (outside the region of the contact surface 26) in order to avoid undesired short circuits. Different suitable materials for producing the dielectric layer 24 are known (e.g. polyimide, photoresist, other structured polymers, etc.). Figure 3Diagram (d) of FIG. 1 shows the semiconductor chips 10 and the sensor chips 20 mounted thereon after the wafer 100 is singulated.

[0033] Figure 4 Figures (a) to (d) show Figure 3 In a first step, a chip carrier 30 (see Figure 4 , diagram (a)). The chip carrier may be a lead frame, a printed circuit board (PCB), a multi-layer substrate or other suitable carrier material. In the depicted embodiment, a lead frame is used as the chip carrier 30.

[0034] The chip-on-chip system, which comprises a semiconductor chip 10 and a sensor chip 20 mounted thereon, is mounted on a chip carrier / lead frame 30. For this purpose, suitable die bonding techniques are known per se (e.g. soldering, gluing) and are therefore not discussed further here. The semiconductor chip 10 (i.e. its contact surface 102, see Figure 3 , Figure (d)) is electrically connected to the relevant chip contacts (such as pins, solder balls, etc.) of the lead frame 30 by means of bonding wires 12. A conventional wire bonding process can be used for this purpose. Figure 4 , The intermediate results are shown in Figure (b).

[0035] In its results Figure 4 In the next step shown in diagram (c), the chip housing (Chip Package, also referred to as encapsulation) is produced from a casting compound 31. Suitable processes are known, for example, as film-assisted molding (FAM). In this case, the area around the sensor element 21 (i.e., the active sensor surface) is left free on the upper side of the sensor chip 20, so that the chip housing 31 has an opening and the medium surrounding the sensor device 2 can interact with the sensor element 21. Figure 1 Unlike the example of FIG. 2 , the cavity (opening in the chip housing 21) does not extend to the semiconductor chip 10. The surface of the semiconductor chip 10 is not exposed but covered by the potting compound 31. The potting compound 21 extends to the edge of the sensor chip 20 or the layer 24 of the protective stripline 23 arranged thereon.

[0036] However, with Figure 1 Differently in the example, for example in Figure 1 In the example of FIG. 5 , a soft potting compound which can be used to cover the sensor element 21 is not necessary, since the strip lines 23 are already protected by a dielectric layer 24 (eg polyimide).

[0037] In the example shown, the lead frame 30 is designed such that it can accommodate a plurality of chips in order to produce a plurality of sensor devices in one step. After the molding process for producing the chip housing, the individual sensor devices 2 are singulated. Figure 4 The results are shown in Figure (d).

[0038] Figure 5 and Figure 6 Shows Figure 2 The two embodiments are alternative to the examples of FIG. The difference between these two embodiments and the above-mentioned examples is basically only in the way and method of how the sensor chip 20 is mounted on the underlying semiconductor chip 10 and how the two chips 10 , 20 are electrically connected.

[0039] exist Figure 5 In the example of FIG. 2 , the sensor chip 20 has plated through holes 28, so-called through silicon vias (TSVs). These plated through holes are used to electrically connect the sensor elements 21 on the upper side of the sensor chip 20 to the contact surfaces 26 ′ (contact pads) on the lower side of the sensor chip 20. In the case of die bonding (i.e. mounting the sensor chip 20 on the underlying chip 10), these contact surfaces 26 ′ are connected to corresponding contact surfaces of the semiconductor chip 10.

[0040] As in the previous examples, the chip housing 31 made of potting compound has an opening / cavity which enables the sensor element 21 on the upper side of the sensor chip 20 to interact with the medium surrounding the sensor device. As in the previous examples, the housing can be produced, for example, by means of FAM. Figure 5 As can be seen in FIG. 1 , no conductor lines / strip conductors are required in this example (see Figure 2 , strip conductor 23) to contact the sensor chip 20. Therefore, in this example, the opening / cavity in the chip housing 31 can also be designed to be larger than in Figure 2 In the example shown, potting compound 31 extends directly to the edge of sensor chip 20. As a result, the sensor device can be designed to be smaller overall.

[0041] Figure 6 An example is Figure 5 An alternative structure for the example of Figure 6, the sensor chip 20 is mounted on the semiconductor chip 10 below by means of flip-chip technology. That is, the contact surface 26 on the upper side of the sensor chip 20 is directly connected to the corresponding contact surface of the semiconductor chip 10 (for example, by welding or a conductive adhesive), wherein the sensor chip 20 is mounted on the semiconductor chip with its upper side facing the semiconductor chip 10 (upper side facing down). In order to enable the sensor element 21 facing the semiconductor chip 10 due to the flip-chip mounting in this example to interact with the surrounding medium, one or more openings 27 extending through the sensor chip 20 or at least extending to the sensor element 21 are provided in the sensor chip 20, and the medium can reach the sensor element 20 through the openings. In addition to the design and mounting technology of the sensor chip 20, Figure 6 Examples with Figure 5 The same as the previous example. In both examples ( Figure 5 and Figure 6 ), the opening in the chip housing can be designed to be very small, that is, the molding compound 31 forming the chip housing extends to the edge of the sensor chip 20, or even overlaps with the edge (contour) of the sensor chip 20.

[0042] Figures 7 to 9 Further alternative embodiments are shown. Figure 7 Examples with Figure 2 The example of FIG. 1 is substantially the same, except that an additional semiconductor chip 10' is arranged next to the semiconductor chip 10 on the lead frame 30. The additional semiconductor chip 10' is connected to the chip contacts (leads, solder balls) of the lead frame 30 and the semiconductor chip 10 via bonding wires 12. The additional semiconductor chip 10' and all bonding wires 12 are completely encapsulated by the casting material 31. In other respects, the above reference Figure 2 The description is applicable.

[0043] Figure 8 The example also matches Figure 2 The example is essentially the same as in the example of FIG. 1 , except that a further chip 20 ′ is arranged on the semiconductor chip 10 next to the sensor chip 20. In the example shown, the chip 20 ′ is mounted on the lower chip 10 in the same manner as the sensor chip 20. As in the sensor chip 20, the electrical contacting of the chip 20 ′ is also achieved by means of strip conductors 23 ′ extending over the edges of the chip 20 ′. The conductor tracks / strip conductors 23 and 23 ′ are as in FIG. Figure 2 The other chip 20' is not a sensor chip and can therefore be completely encapsulated by the casting material 31. Alternatively, the other chip 20' can also be designed as a sensor chip. In this case, the casting material (housing) has a further cavity. In another embodiment, the other chip 20 is connected to the chip 10 below by means of flip chip technology or through silicon vias.

[0044] Fig. 9 The example shows Figure 2 Another modification of the example of Figure 2 The only difference from the above-mentioned example is that the semiconductor chip 10 is not electrically connected to the corresponding chip contacts of the lead frame 30 via bonding wires 12, but via conductor tracks / strip conductors 23". These conductor tracks 23" (as well as strip conductors 23 and 23') can be produced by means of a printing method or electrochemical deposition (electroplating). This method is suitable for producing strip conductors on three-dimensional structures (and therefore over chip edges).

[0045] exist Figures 2 to 9 In the example of , the sensor chip 20 (and possibly the further chip 20 ′) is bonded to the wafer before it is cut into individual chips. This can be achieved in such a way that wire bonding technology is also abandoned for electrically contacting the sensor chip 20. The abandonment of bonding wires also enables a significant reduction in the size of the opening / cavity in the chip housing. As in Figure 2 , 5 As shown in FIG6 , the molding compound 31 forming the chip housing can reach the edge of the sensor chip 20 or even overlap the chip edge. The strip lines can (unlike the bonding wires) be protected by a relatively hard dielectric layer 24 (e.g. polyimide) and no soft casting compound, such as silicone, is required, which can additionally improve the performance of the sensor chip. The molding compound 31 does not have to protrude or does not have to protrude significantly beyond the upper side of the sensor chip (e.g. dielectric layer), i.e. the cavity can (in contrast to the bonding wires) be formed by the relatively hard dielectric layer 24 (e.g. polyimide). Figure 1 Additional protection of the sensor element 21 by a soft potting compound is an option, but is no longer absolutely necessary.

[0046] In MEMS sensors, in particular pressure sensors, the concepts described here can only be used reasonably if the residual stresses generated in the sensor chip are decoupled from the sensor element (MEMS) integrated therein (in particular the packaging of the semiconductor chip after chip-on-chip mounting of the sensor chip). Figures 2 to 9 ), which is facilitated by the grooves (see Figure 2 and Figure 3 , trench 35 ), which surrounds the sensor element and enables mechanical decoupling between the sensor element (MEMS) and the surrounding silicon.

Claims

1. A sensor device, comprising: Chip carrier (30); A semiconductor chip (10) mounted on the chip carrier (30); an electrical connection (12, 23") between a connection surface (102) of the semiconductor chip (10) and a corresponding connection surface of the chip carrier (30); a sensor chip (20) having a sensor element (21) arranged on the semiconductor chip (10); and a molding compound (31) forming a chip housing, which at least partially encapsulates the semiconductor chip (10) and the electrical connections (12, 23") and has an opening in the region of the sensor element (21) so that the sensor element can interact with a medium surrounding the sensor device, The molding compound (31) covers the semiconductor chip (10) up to the sensor chip (20), and The sensor chip (20) has a trench (25) which mechanically decouples the sensor element from the rest of the sensor chip (20).

2. The sensor device according to claim 1, wherein the semiconductor chip (10) and the sensor chip (20) have corresponding contact surfaces (101, 25), which are connected by means of conductor tracks (23) extending over an edge of the sensor chip (20). 3 . The sensor device as claimed in claim 2 , wherein the conductor track ( 23 ) is produced by means of electrochemical deposition or by means of a printing method.

4. The sensor device according to claim 2 or 3, wherein the molding compound (31) at least partially covers the conductor track (23). 5 . The sensor device according to claim 2 , wherein the conductor track ( 23 ) is covered by a dielectric layer ( 24 ).

6. The sensor device according to claim 1, The sensor chip (20) is mounted on the semiconductor chip (10) by means of flip chip technology, so that the sensor element (21) faces the semiconductor chip (10), and The sensor chip (20) has an opening (27) which establishes a connection between the sensor element (21) and the surroundings.

7. The sensor device according to claim 1, wherein the sensor element (21) is arranged on the upper side of the sensor chip (20), All contact surfaces (25') of the sensor chip which are connected to the semiconductor chip (10) are arranged on the underside of the sensor chip (20).

8. The sensor device according to claim 7, wherein the sensor chip (20) has a plated through-hole (28) which extends through the sensor chip (20) and electrically connects the sensor chip (20) to the semiconductor chip (10).

9. The sensor device according to claim 1 , wherein the electrical connection ( 12 , 23 ″) between the connection area ( 102 ) of the semiconductor chip ( 10 ) and the corresponding connection area of ​​the chip carrier ( 30 ) is formed by a bonding wire ( 12 ).

10. The sensor device according to any one of claims 1 to 9, The molding compound (31) has an opening with a contour which is approximately aligned with the contour of the sensor chip, and / or The side surface of the sensor chip (20) is in physical contact with the molding compound (31).

11. The sensor device according to any one of claims 1 to 10, wherein the sensor element (21) is a micro-electromechanical system (MEMS).

12. A method comprising: Providing a wafer (100) having a plurality of semiconductor chips (10); Bonding a plurality of sensor chips (20) to corresponding semiconductor chips (20), wherein the sensor chips (20) each have a sensor element (21) and a groove (25), wherein the groove mechanically decouples the sensor element (21) from the remaining sensor chips (20); Singulating the semiconductor chip (10) together with the sensor chip (10) arranged on the semiconductor chip; The semiconductor chip is mounted on a corresponding chip carrier (30); and the semiconductor chip is subsequently encapsulated with a molding compound, wherein an opening remains free in the molding compound in the region of the sensor element of the sensor chip.

13. The method according to claim 12, further comprising, before singulating the semiconductor chip: Conductive tracks are produced in order to make contact with the sensor chip and a corresponding semiconductor chip, wherein the conductive tracks extend over the edges of the sensor chip.

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