Electronic device and method for manufacturing an electronic device

Abstract

Electronic device (100), comprising: - a carrier board (1) with a top surface (11), - an electronic chip (2) mounted on the upper surface (11) of the carrier board (1), the electronic chip (2) having a mounting side (21) facing the upper surface (11) of the carrier board (1), and - a flexible mounting layer (3) arranged between the upper surface (11) of the carrier board (1) and the mounting side (21) of the electronic chip (2) and which secures the electronic chip (2) to the carrier board (1), where - the fastening side (21) has at least a first area (22) and a second area (23), - the electronic chip (2) has at least one chip contact element (24) in the first area (22), - a connecting element (4) on which at least one first area (22) is arranged and which connects at least one chip contact element (24) to the upper surface (11) of the carrier board (1), - the flexible fastening layer (3) separates the second area (23) from the connecting element (4), - the carrier board (1) has at least one carrier contact element (14) which is connected to the at least one chip contact element (24) by means of the connecting element (4), - the at least one chip contact element (24) and / or the at least one carrier contact element (14) comprises a stud bump and / or a column-shaped structure and is designed to be immersed in a connecting material (40) of the connecting element (4), and - the electronic chip (2) is attached and fixed to the carrier board (1) only or at least substantially by means of the mounting layer (3) and the at least one connecting element (4) and the electronic device (100) is free of a backing material.

Description

[0001] Embodiments of the present invention relate to an electronic device, in particular an electronic device comprising a substrate and an electronic chip mounted on the substrate, and a method for manufacturing the electronic device. The electronic device can, for example, be a sensor device. In particular, the electronic device can comprise a MEMS chip (MEMS: microelectromechanical system). The electronic device can, for example, be a MEMS microphone.

[0002] MEMS microphones utilize microstructured, primarily silicon-based acoustoelectric transducers. These highly sensitive sensor chips feature thin, movable diaphragms, which, combined with their placement in a protective housing and the mismatch of different thermal expansion coefficients among the materials, makes them highly susceptible to mechanical stress. The most common way to keep such stress to a minimum is to use a conventional die mounting with a soft, thick bond line. In this case, the diaphragm, and thus the electrical contacts, are positioned vertically from the substrate, and the internal electrical connections to the housing and / or a complementary ASIC (application-specific integrated circuit) are made via wire bonding.This leads to two significant disadvantages: In the case of the dominant bottom-port configuration, the internal MEMS cavity cannot contribute to the useful acoustic rear volume but adds to the parasitic front volume, both of which degrade the microphone's performance. Furthermore, the bond wires require considerable lateral space, for example for the substrate landings, and clearance, for example for the wire loop and a safety distance to the cap, both of which increase the component's dimensions, hindering overall miniaturization efforts.

[0003] A flip-chip arrangement on solder mounds could provide a solution to both problems. However, in this case, the sensor chip is rigidly coupled to the package substrate, making it susceptible to static arrangement stress, offset from solder remelting, temperature-induced stress due to a CTE discrepancy between the sensor and package materials, and dynamic stress from external influences.

[0004] German patent application DE 10 2012 107 403 A1 discloses a method for manufacturing a chip package module comprising a chip with an input area, for example, with a MEMS structure, and connection pads on a first chip side. A buffer layer is applied to the first chip side, designed to be thicker than the connection pads and to insulate the input area from the connection pads. The chip with the buffer layer can be mounted on a substrate that has openings in the areas of the connection pads, allowing the connection pads to be electrically connected to the substrate via wires. A molding process can be used to form a molding compound around the chip, filling the openings in the substrate and the buffer layer while leaving the input area 224 uncovered.

[0005] US Patent 6,140,144 A discloses a method for mounting a sensor chip with a sensor element onto a substrate, wherein the sensor chip is first electrically connected to the substrate via bond pads using solder or a conductive polymer. Subsequently, a backing material is applied to encapsulate the bond pads. The backing material can be either a material such as an epoxy resin or another material compatible with specific processing requirements such as curing temperature or coefficient of thermal expansion.

[0006] Documents DE 10 2018 104 279 A1 and US 2009 / 0 243 006 A1 also describe MEMS chips mounted on carriers.

[0007] One objective of at least certain embodiments is to provide an electronic device that avoids or at least reduces the problems mentioned above. Another objective of at least certain embodiments is to provide a method for manufacturing the electronic device.

[0008] These tasks are achieved, among other things, by an electronic device and a method for manufacturing an electronic device according to the independent claims. Further embodiments and configurations are the subject of the dependent claims.

[0009] According to at least one embodiment, an electronic device comprises a substrate with an upper surface. An electronic chip, which may hereinafter also be referred to as a "chip", is attached to the upper surface of the substrate. The electronic chip can, for example, be a sensor chip. In a preferred embodiment, the electronic chip is a MEMS chip.

[0010] According to at least one further embodiment, the carrier board and the electronic chip are provided in a method for manufacturing the electronic device. In particular, the electronic chip is provided for mounting on the carrier board. The embodiments and features described above and below apply to the electronic device and to the method for manufacturing the electronic device.

[0011] According to another embodiment, the carrier board provides electrical connections for connecting to the electronic chip. In particular, the carrier board can be a laminated multilayer board based on HTCC (high-temperature co-fired ceramic), LTCC (low-temperature co-fired ceramic), organic materials such as polymers, and / or glass. Conductive traces and / or vias can provide electrical connections between the elements mounted on the carrier board and external solder pads.

[0012] The electronic chip has a mounting side that faces the top surface of the substrate when mounted on the substrate. Furthermore, the electronic chip may have a top surface facing away from the top surface of the substrate and side walls connecting the mounting side to the top surface. The mounting side comprises at least one first region and a second region. In particular, the chip has at least one chip contact element in the first region, wherein the chip contact element is configured for electrically connecting the chip to the top surface of the substrate. Preferably, the chip has multiple first regions, with at least one chip contact element in each first region. Accordingly, the electronic chip preferably comprises multiple chip contact elements and multiple first regions, with at least one chip contact element located in each first region.

[0013] Furthermore, each of the one or more contact elements of the electronic chip comprises, or is configured as, a contact pad and / or stud bump. A contact pad can, for example, be an electrode pad of the electronic chip. A stud bump can be located, for example, on an electrode pad or another surface conductor element of the electronic chip. To create a stud bump, a metal sphere, comprising or consisting of, for example, gold, is formed using a standard wire bonding process. After the sphere is bonded to the electrode pad, wire clamps are closed and the bonding head is moved to cut the wire. If the direction of movement is substantially perpendicular to the bonding side, a tail may be left on the solder bump.Depending on the movement parameters, the width and length of the extension, and thus the size and shape of the stud bump, can be adjusted.

[0014] Furthermore, the carrier board has at least one carrier contact element, wherein the at least one carrier contact element preferably comprises a contact pad and / or a stud bump. In particular, the carrier board can include a dedicated carrier contact element for each of the chip contact elements. In addition, the carrier board can include carrier contact elements for the electrical connection of additional electronic components, such as an ASIC.

[0015] Furthermore, the electronic device comprises at least one connecting element that connects the at least one chip contact element to the upper surface of the carrier board. Accordingly, the at least one connecting element is arranged on the at least one first region of the mounting surface of the electronic chip. Preferably, the at least one connecting element connects the at least one chip contact element to the at least one carrier contact element. In particular, each of the chip contact elements is connected to a carrier contact element by means of a connecting element. The at least one connecting element is preferably electrically conductive. For the manufacture of the electronic device, a connecting material is preferably arranged on the upper surface of the carrier board or on the at least one first region of the electronic chip. For example, the connecting material comprises an electrically conductive adhesive.In particular, the bonding material can be cured and the bonding element can be formed, which then preferably comprises or is made from a cured electrically conductive adhesive.

[0016] Preferably, the at least one connecting element is made of a material with a modulus of elasticity of 300 MPa or less, and preferably 100 MPa or less. In particular, the at least one connecting element can be made of a material with this modulus of elasticity for a temperature range of at least -20°C to 100°C, including the limit values, and preferably between at least -40°C and 120°C, including the limit values. The at least one connecting element can comprise or be a flexible adhesive, for example, silicone, filled with conductive particles, for example, silver particles or carbon black particles, and / or an intrinsically conductive polymer.

[0017] The electronic device further comprises a flexible mounting layer. The flexible mounting layer is arranged between the upper surface of the carrier board and the mounting side of the electronic chip. The feature "flexible" refers to mechanical properties specified below. In particular, the mounting layer secures the electronic chip to the carrier board. This preferably means that the electronic chip, and especially a portion of the mounting side, is attached to a portion of the upper surface of the carrier board. The mounting layer can preferably be in direct contact with a portion of the mounting side or with a portion of the upper surface of the carrier board, or, more preferably, with both.

[0018] According to a further embodiment, to manufacture the electronic device, a mounting material is applied to at least a portion of the upper surface of the substrate or at least a portion of the mounting side of the electronic chip. The mounting material is applied in a structured manner to form the flexible mounting layer. For example, the mounting material can be applied as a continuous layer to the entire upper surface of the substrate or to a portion thereof, or to the entire mounting side of the electronic chip or a portion thereof. Subsequently, the mounting material can be selectively removed and thus structured to obtain the desired structure. The structuring can be carried out, for example, using laser ablation and / or photolithography and / or cutting and / or peeling.The binder material can also be deposited as a curable, viscous material using additive structuring, such as 3D printing, or subtractive structuring, such as lithography. Depending on the binder material, the structured binder material can be partially or fully cured to form the binder layer, or the structured binder material can already form the binder layer without an additional curing step. Curing, if required, can be performed before or, preferably, after the chip is mounted on the substrate. It may also be possible to produce and, in particular, structure the binder layer separately from the chip and the substrate, and to apply the binder layer in a pre-structured form.

[0019] After the mounting material or mounting layer has been placed on the electronic chip or on the substrate, the electronic chip is positioned on the substrate such that the mounting side of the electronic chip faces the top surface of the substrate. The mounting layer can secure the electronic chip to the substrate, so that the electronic chip is fixed to the substrate at least partially or preferably substantially by means of the mounting layer.

[0020] According to a further embodiment, the bonding layer adheres to the mounting side of the electronic chip or to the upper surface of the substrate, or preferably to both. For example, the bonding layer has intrinsic bonding capabilities, meaning that the bonding material, and in particular the bonding layer in the finished electronic device, can bond directly to the adjacent material of the electronic chip and / or the substrate. This can mean that the bonding layer has at least surface bonding capabilities by means of an adhesive surface. Alternatively, the bonding layer can comprise an adhesive layer on one of the surfaces adjacent to the chip and the substrate, or on both surfaces.

[0021] According to a further embodiment, the bonding layer comprises a polymer material. Preferably, the bonding layer is made of a material with a modulus of elasticity equal to or greater than 0.5 MPa and equal to or less than 100 MPa, and preferably equal to or greater than 3 MPa and equal to or less than 30 MPa. Particularly preferably, the bonding layer is made of a material with this modulus of elasticity in a temperature range of at least -20°C to 100°C, including the limits, and preferably between at least -40°C and 120°C, including the limits. Furthermore, the bonding layer can have a thickness of equal to or greater than 10 µm and equal to or less than 500 µm. It may be particularly preferred if the bonding layer has the aforementioned flexibility and is simultaneously adhesive and inherently stable.The bonding layer comprises, for example, a silicone-based polymer, such as an ultra-low stress silicone polymer, or a soft B-stage epoxy material, or is made from such a material, with the B-stage epoxy material being in a cured state in the finished electronic device, sometimes referred to as C-stage.

[0022] According to a further embodiment, the flexible mounting layer separates the second region of the mounting side of the electronic chip from the connecting element on the at least one first region. In particular, the material of the mounting layer can be arranged between the at least one first region and the second region, thereby acting as a barrier or dam and preventing the connecting element material from the at least one first region from overflowing, being squeezed out, smeared, or bleeding from the second region of the mounting side during manufacturing and in the finished electronic device. Most preferably, the second region can be surrounded by the mounting layer. In other words, the mounting layer can have an opening in the form of a through-hole through which the second region is accessible.Furthermore, each of the at least one connecting element can be arranged in an opening, for example a through-hole, in the fastening layer. Accordingly, the fastening side in the second area is preferably free of the at least one connecting element and of the fastening layer.

[0023] According to a further embodiment, the mounting surface of the electronic chip is spaced apart from the upper surface of the substrate, thereby defining a gap between the second region of the mounting surface and the upper surface. The height of the gap can be essentially determined by the thickness of the mounting layer. In particular, the gap is free of any backing material. In other words, the electronic chip can be mounted and fixed to the substrate solely, or at least substantially, by means of the mounting layer and the at least one connecting element, thus avoiding any further backing material, such as adhesive materials, which are commonly applied between a chip and a substrate.

[0024] For example, the electronic chip has an active sensor element in the second area. If the electronic chip is a microphone chip, the chip can include at least one diaphragm and / or a backplate in the second area.

[0025] Due to the structured mounting layer, the chip is attached to the substrate, while the diaphragm is simultaneously held free from the at least one connecting element. The substrate may have an opening, forming, for example, an acoustic port, facing the second area. Furthermore, the flexible mounting layer can provide an acoustic seal between the mounting surface and the top of the electronic chip.

[0026] Further features, advantages and expediencies will become apparent from the following description of exemplary embodiments in conjunction with the figures. Fig. Figures 1 to 13 show schematic representations of process steps of a method for manufacturing an electronic device and of an electronic device according to several embodiments. Fig. 14A and Fig. Figure 14D shows schematic representations of features of a mounting layer for an electronic device according to further embodiments, and Fig. Figure 15 shows a schematic representation of an electronic device according to a further embodiment.

[0027] In the figures, elements of the same design and / or function are identified by the same reference symbols. It is understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

[0028] The Fig. Figures 1 to 13 show process steps of a method for manufacturing an electronic device 100 according to several exemplary embodiments. As, for example, in Fig. As can be seen in Figure 7, the electronic device 100 comprises a carrier board 1 on which an electronic chip 2 is mounted. The electronic chip 2 can, for example, be a sensor chip and preferably a MEMS chip such as a MEMS microphone. Although the following description relates to such an application, the present invention is not limited to MEMS microphones, but can also be useful for other types of voltage-sensitive sensors as well as electronic components in general.

[0029] Although the figures and the general section above describe the various embodiments of the electronic device and the method for manufacturing the electronic device in connection with a single electronic device, the method for manufacturing the electronic device can be panel-based, so that a large number, typically several hundred, of individual electronic devices can be manufactured on an integral carrier board substrate, which, for example, in one of the last process steps is separated into individual electronic devices, each having an electronic chip on a carrier board.

[0030] As in Fig. As shown in Figure 1, a laminated multilayer circuit board, for example based on HTCC, LTCC, polymer, or glass, is provided as the carrier board 1 and thus as a housing substrate. The carrier board 1 comprises an upper surface 11 and a lower surface 12 facing away from the upper surface 11. Furthermore, the carrier board 1 has an opening 13 extending from the upper surface 11 to the lower surface 12, which acts as a sound port opening in the completed electronic device. For applications other than microphone applications, the opening 13 can also be omitted. On the upper and lower surfaces 11, 12, the carrier board 1 has carrier contact elements 14, which can be configured as contact pads. Conductors and vias provide electrical connections between the carrier contact elements 14.Ground planes (not shown) can improve electromagnetic shielding in combination with a cap, preferably a metal cap, attached to the carrier board 1 by means of a suitable bonding material, for example a solder or a conductive adhesive, as shown in . Fig. 15 is shown.

[0031] In a further procedural step, as in Fig. As shown in Figure 2, a fastening material 30 is applied to the upper surface 11 of the carrier board 1 to produce a flexible fastening layer 3, which is in Fig. 3 can be seen. As shown, the mounting material 30 can be applied as a partial layer in this region of the upper surface 11, where the electronic chip is subsequently mounted. The mounting material 30 is preferably applied directly to the upper surface 11, i.e., in direct contact with the upper surface 11 of the substrate 1. In particular, the mounting material 30 is a polymer material. The mounting material 30, and especially the mounting layer 3, preferably has a thickness of 10 µm or greater and 500 µm or less.

[0032] The polymer material used as the binder material 30, and thus for the binder layer 3, preferably has a modulus of elasticity of 0.5 MPa or greater than 0.5 MPa and 100 MPa or less, and preferably 3 MPa or greater than 30 MPa or less, over a wide temperature range, thereby providing sufficient flexibility. In particular, the binder layer 3 preferably exhibits said modulus of elasticity in a temperature range of at least -20°C to 100°C, including the limit values, and preferably between at least -40°C and 120°C, including the limit values. The polymer material, and thus the binder layer, comprises, for example, a silicone-based polymer, such as an extremely low-stress silicone polymer, or a soft B-stage epoxy material or a C-stage epoxy material, or is made from such materials.The fastening material 30, and in particular the fastening layer 3, may exhibit surface and / or intrinsic bonding capabilities and thus adhere to the upper surface 11 of the carrier board 1. It is also possible that the fastening layer 3 comprises an adhesive layer on the surface facing the carrier board 1 and / or on the surface facing away from the carrier board 1.

[0033] As in Fig. As shown in Figure 3, the fastening material is structured in such a way that the opening 13 and the carrier contact elements 14 of the carrier board 1 are exposed by forming openings 31, 32 by selectively removing fastening material. Fig. Figure 4 shows a corresponding top view of the upper surface 11 of the carrier board 1. The structuring can be carried out using, for example, photolithography or laser ablation, or any other method suitable for the selective removal of binder material. Depending on the polymer material, the binder layer 3 can be finished after structuring, as shown in Fig. 3 is shown. Alternatively, it may be possible to partially or fully cure the fastening material to form the fastening layer 3, with the curing being carried out immediately after the structuring step or after one of the later process steps described below.

[0034] It is also possible to attach the fastening material 30 to the entire upper surface 11 of the carrier board 1, followed by a more extensive removal. As in Fig. As illustrated in Figure 5, this can be done, for example, in combination with cutting and peeling. The layer can also be deposited as a curable, viscous polymer material using additive structuring, such as 3D printing, or subtractive structuring, such as lithography. Another possibility is to structure the attachment layer 3 separately from the substrate 1 and to apply the attachment layer 3 in a pre-structured form.

[0035] In a subsequent procedural step, as in Fig. As shown in Figure 6, the electronic chip 2 is provided for mounting on the carrier board 1 using the mounting layer 3 as a flexible mounting frame. The electronic chip 2 has a mounting side 21 facing the upper surface 11 of the carrier board 1. Furthermore, the electronic chip 2 has a top surface facing away from the upper surface 11 and side walls connecting the mounting side 21 to the top surface. The mounting side 21 of the chip 2 has at least one first region 22 and a second region 23. As shown, the chip 2 can have at least one chip contact element 24 in the at least one first region 21, wherein the chip contact element 24 is configured for electrically connecting the chip 2 to the upper surface 11 of the carrier board 1, in particular by means of a connecting material.Preferably, the chip 2 has several first regions 22, each of which contains at least one chip contact element 24. In the second region 23, the chip 2, which, as explained above, is configured as a MEMS microphone chip in the illustrated embodiments, has a diaphragm and a backplate. The electronic chip 2 is provided such that it is mounted on the carrier board 1 such that the diaphragm and the backplate of the chip 2 in the second region 23 face the opening 13 in the carrier board 1 and thus the opening 31 in the mounting layer 3.

[0036] As in the exemplary embodiment of the Fig. As shown in Figure 6, the openings 32, i.e., the open contact holes, in the bonding layer 3 can serve as molds for an electrically conductive bonding material 40, which is inserted into the holes. The bonding material 40 can preferably comprise or be a flexible adhesive filled with conductive particles, for example, silver particles or carbon black particles, or an intrinsically conductive polymer. In particular, a relatively low modulus of elasticity of 300 MPa or less, and preferably 100 MPa or less, is preferred. For example, the bonding material can be based on a silicone polymer.

[0037] Fig. Figure 6 shows the openings 32 with a partial filling of the bonding material 40, the filling being carried out, for example, by dispensing, jetting, or pin transfer. The partial filling level is particularly advantageous because, while a level that is too low can prevent a conductive connection with the chip contact elements 24, a level that is too high can prevent proper inclusion within the openings 32. Therefore, in the illustrated embodiment, the chip contact elements 24 comprise stud bumps designed to be immersed in the bonding material 40, which allows for a certain level tolerance.Alternatively, other conductive column structures can be used for the chip contact elements 24, where it is very advantageous if the outer diameter of the column structures is significantly smaller than the inner diameter of the openings 32, so that the level of the connecting material 40 increases at a lower rate compared to the depth to which such a column structure is sunk.

[0038] As in Fig. As shown in Figure 7, the electronic chip 2 is arranged on the carrier board 1 such that the mounting side 21 of the electronic chip 2 faces the upper surface 11 of the carrier board 1, and the mounting layer 3 secures the electronic chip 2 to the carrier board 1. In particular, a portion of the mounting side 21 of the chip 2 is in direct contact with the mounting layer 3, so that the mounting layer 3 adheres to the mounting side 21. The bonding material 40 can be cured so that the bonding elements 4 are formed on the first areas 22.

[0039] As in Fig. As can be seen in Figure 7, the flexible mounting layer 3 separates the second region 23 of the mounting side 21 of the electronic chip 2 from the connecting elements 4 on the first regions 22. In particular, the material of the mounting layer 3 is arranged between the first regions 22 and the second region 23 and acts as a barrier or dam, preventing the material of the connecting elements 4 from the first regions 22 from overflowing, squeezing, smearing, or bleeding from the second region 23 of the mounting side 21 during manufacturing and in the finished electronic device 100. Most preferably, the second region 23 is surrounded by the mounting layer 3. Accordingly, the mounting side 21 in the second region 23 is free of the material of the connecting elements 4 and of the material of the mounting layer 3.

[0040] According to a further embodiment, as in Fig. As shown in Figure 8, the mounting layer 3 is applied to the mounting side 21 of the electronic chip 2 before the chip 2 is mounted on the carrier board 1. Similar to the preceding embodiments, the mounting layer 3 can be produced by applying and structuring a mounting material onto the mounting side 21, or it can be produced separately from the chip 2 and placed on the mounting side 21. The bonding material 40 is applied to the upper surface 11 of the carrier board 1. In particular, the bonding material 40 is applied to the carrier contact elements 14, which are to be connected to the chip contact elements 24. Alternatively, the bonding material 40 can also be applied to the chip carrier elements 24 in the openings 32 before the chip 2 with the mounting layer 3 is placed on the carrier board 1.

[0041] After arranging the chip 2 with the mounting layer 3 as a flexible mounting frame on the upper surface 11 of the carrier board 1, the openings 32 in the mounting layer 3 can be filled flush with the bonding material and thus with the bonding elements 4, as shown in Fig. Figure 7 shows that the mounting layer 3 can be arranged directly on the mounting side 21 of the chip 2 and directly on the upper surface 11 of the carrier board 1. It is also possible for the openings 32 to be partially filled with the bonding material and thus with the bonding elements. Alternatively, the amount of bonding material 40 applied can be in excess of the size of the openings 32, so that part of the bonding material and thus the bonding elements 4 remains outside the openings 32 between the mounting layer 3 and the upper surface 11 of the carrier board 1. Accordingly, the mounting layer 3 and thus the chip 2 can also be attached to the carrier board 1 by means of the bonding elements 4, as shown in a partial view of the electronic device 100 in Figure 7. Fig. 9 is shown.

[0042] The Fig. 10, Fig. 11 and Fig. Figure 12 shows further embodiments, wherein the electronic chip has two chip contact elements 24 comprising contact pads instead of the stud bumps of the preceding embodiments. As in connection with the Fig. 8 and Fig. As explained in Figure 9, the mounting layer 3 is applied to the mounting side 21 of the chip 2 before the chip 2 is placed on the carrier board 1. Furthermore, the bonding material 40 is applied to the openings 32 of the mounting layer 3, and thus to the chip contact elements 24, before the chip 2 is placed on the carrier board 1. As explained in the Fig. 10 and Fig. As shown in Figure 11, the amount of interconnect material can be adjusted so that the openings 32 in the mounting layer 3 are filled flush with the interconnect material 40 and thus with the interconnect elements 4. Particularly in conjunction with a bumpless connection, i.e., without stud bumps, it can be advantageous to position the mounting layer 3 on the mounting side 21 of the chip 2, since some squeezing of the interconnect material is acceptable on the side of the substrate 1. Furthermore, the amount of interconnect material can exceed the volume of the openings 32, leaving some of the interconnect material outside the openings 32 between the mounting layer 3 and the top surface 11 of the substrate 1, as shown in Figure 11. Fig. Figure 12 shows that, however, it is also possible with a bump-free connection for the mounting layer 3 to be placed on the carrier board 1 before the chip 2 is placed on the carrier board 1, as shown in conjunction with the Fig. 1 to 7 are explained.

[0043] According to a further embodiment, which is described in Fig. As shown in Figure 13 in a partial view of the electronic device 100, the carrier board 1 may further comprise carrier contact elements 14, which include stud bumps or other column-like structures. In this case as well, it may be preferred that the mounting layer 3 is arranged on the mounting side 21 of the chip 2 before the chip 2 is arranged on the carrier board 1, and that the bonding material 40 is applied to the openings 32 of the mounting layer 3 and thus to the chip contact elements 24 before the chip 2 is arranged on the carrier board 1, as in conjunction with the Fig. 10 to 12 is explained.

[0044] The Fig. Figures 14A to 14D show top views of the layout of the mounting layer 3 according to further embodiments. The black dots indicate possible positions of the chip contact elements and / or the carrier contact elements. To optimize the fulfillment of the requirements of the electronic chip and, in particular, the electronic device, the footprint of the mounting layer 3 can be adapted to meet the following requirements: - Secure attachment of the electronic chip to the carrier board; - in the case of a microphone application, providing an acoustic seal between the front and back of the electronic chip, i.e., between the second area of ​​the mounting side and the top of the electronic chip; and - Providing a barrier or dam that keeps the connecting material and, in particular, the contact elements away from the second area of ​​the mounting side of the electronic chip.

[0045] Fig. Figure 14A shows the full-surface design, which has already been shown in connection with the preceding embodiments. According to the embodiment of Fig. In 14B, the area of ​​the fastening layer 3 is reduced, while the fasteners remain contained within the openings 32. In contrast, the Fig. 14C and Fig. 14D Exemplary embodiments of the mounting layer 3, which have ring-like shapes, thus resembling sealing rings. In these exemplary embodiments, a potential ejection of the bonding material towards the second area of ​​the mounting side of the electronic chip, which is located within the opening 31, can also be prevented, and an acoustic seal can be ensured.

[0046] Fig. Figure 15 shows a further embodiment of the electronic device 100, which includes, by way of example, the carrier board 1, the electronic chip 2 and the mounting layer 3 with the connecting elements 4, as in conjunction with the Fig. 1 to 7 are explained. Alternatively, the following can be used: Fig. The electronic device 100 shown in Figure 15 may include any other feature described in connection with the preceding embodiments. The electronic device 100 further includes an additional circuit to achieve a fully functional microphone. In particular, the electronic device 100 may include an ASIC 5 for signal conditioning, which may be mounted on the carrier board 1 in the same manner as the electronic chip 2 or as described in Figure 15. Fig. Figure 15 shows that the electronic device 100 is attached using solder pads or any other arrangement and connection method. Furthermore, the electronic device 100 includes a cap as a counterpart for the carrier board 1, for example a soldered metal cap, to complete the package housing.

[0047] Alternatively or in addition to the features described in connection with the figures, the embodiments shown in the figures may include further features that are described in the general part of the description. Furthermore, features and embodiments shown in the figures may be combined with one another, even if such a combination is not expressly described.

[0048] The invention is not limited by the description based on the exemplary embodiments. Instead, the invention includes any new feature and any combination of features, which in particular includes any combination of features in the claims, even if that feature or combination itself is not expressly specified in the claims or exemplary embodiments. Reference symbol list 1 carrier board 2 electronic chips 3. Mounting layer 4 Connecting element 5 ASIC 6 caps 11 upper surface 12 lower surface 13 Opening 14 Carrier contact element 21 Mounting side 22 first area 23 second area 24 chip contact elements 30 fastening materials 31 Opening 32 Opening 40 Connecting material 100 electronic devices

Claims

[1] Electronic device (100) comprising: - a carrier board (1) with a top surface (11), - an electronic chip (2) mounted on the upper surface (11) of the carrier board (1), the electronic chip (2) having a mounting side (21) facing the upper surface (11) of the carrier board (1), and - a flexible mounting layer (3) arranged between the upper surface (11) of the carrier board (1) and the mounting side (21) of the electronic chip (2) and which secures the electronic chip (2) to the carrier board (1), where - the fastening side (21) has at least a first area (22) and a second area (23), - the electronic chip (2) has at least one chip contact element (24) in the first area (22), - a connecting element (4) on which at least one first area (22) is arranged and which connects at least one chip contact element (24) to the upper surface (11) of the carrier board (1), - the flexible fastening layer (3) separates the second area (23) from the connecting element (4), - the carrier board (1) has at least one carrier contact element (14) which is connected to the at least one chip contact element (24) by means of the connecting element (4), - the at least one chip contact element (24) and / or the at least one carrier contact element (14) comprises a stud bump and / or a column-shaped structure and is designed to be immersed in a connecting material (40) of the connecting element (4), and - the electronic chip (2) is attached and fixed to the carrier board (1) only or at least substantially by means of the mounting layer (3) and the at least one connecting element (4) and the electronic device (100) is free of a backing material. [2] Electronic device (100) according to the preceding claim, wherein the second area (23) on the mounting side (21) is surrounded by the mounting layer (3) and is free from the at least one connecting element (4) and from the mounting layer (3). [3] Electronic device (100) according to one of the preceding claims, wherein the connecting element (4) is arranged in an opening (32) of the fastening layer (3). [4] Electronic device (100) according to one of the preceding claims, wherein the fastening layer (3) adheres to the fastening side (21) of the electronic chip (2). [5] Electronic device (100) according to one of the preceding claims, wherein the fastening layer (3) adheres to the upper surface (11) of the carrier board (1). [6] Electronic device (100) according to any of the preceding claims, wherein the mounting layer (3) comprises a polymer material, preferably a silicone-based polymer or a B-stage epoxy material or a C-stage epoxy material. [7] Electronic device (100) according to any of the preceding claims, wherein the mounting layer (3) has a thickness of 10 µm or greater and 500 µm or less. [8] Electronic device (100) according to one of the preceding claims, wherein the connecting element (4) comprises an electrically conductive adhesive. [9] Electronic device (100) according to one of the preceding claims, wherein in a temperature range between at least -20°C and 100°C, including the limit values, and preferably between at least -40°C and 120°C, including the limit values, - the fastening layer (3) has a modulus of elasticity of 0.5 MPa or greater than 0.5 MPa and 100 MPa or less than 100 MPa, and preferably 3 MPa or greater than 3 MPa and 30 MPa or less than 30 MPa, and - the connecting element (4) has a modulus of elasticity of 300 MPa or less and preferably 100 MPa or less. [10] Electronic device (100) according to any of the preceding claims, wherein the electronic chip (2) is a MEMS chip. [11] Method for manufacturing an electronic device (100) according to any one of the preceding claims, wherein - a carrier board (1) with a top surface (11) and an electronic chip (2) with a mounting side (21) having at least one first area (22) and one second area (23) are provided, - a fastening material (30) is applied to the top surface (11) of the carrier board (1) or to the mounting side (21) of the electronic chip (2) in a structured manner to form a flexible mounting layer (3), - a connecting material (40) is arranged on the upper surface (11) of the carrier board (1) or on the at least one first area (22) of the electronic chip (2), - the electronic chip (2) is arranged on the carrier board (1) such that the mounting side (21) of the electronic chip (2) faces the upper surface (11) of the carrier board (1) and the mounting layer (3) secures the electronic chip (2) to the carrier board (1), the bonding material (40) being cured to form a bonding element (4). [12] Method according to claim 11, wherein the fastening material (30) is cured to form the fastening layer (3).

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