MEMS Package

Abstract

A package includes a support structure having an electrically insulating material, a microelectromechanical system (MEMS) component, a cover structure having an electrically insulating material and mounted on the support structure for at least partially covering the MEMS component, and an electronic component embedded in one of the support structure and the cover structure. At least one of the support structure and the cover structure has or provides an electrically conductive contact structure.

Claims

1. A package, comprising: a support structure comprising an electrically insulating material; a microelectromechanical system (MEMS) component; a cover structure comprising an electrically insulating material and mounted on the support structure for at least partially covering the MEMS component, wherein the cover structure is configured as a printed circuit board, or as a section thereof; and an electronic component embedded in one of the support structure and the cover structure; wherein at least one of the support structure and the cover structure comprises an electrically conductive contact structure.

2. The package according to claim 1, wherein the support structure is configured as a circuit board.

3. The package according to claim 1, wherein the electrically insulating material of at least one of the support structure and the cover structure comprises at least one of the group consisting of resin, Bismaleimide-Triazine resin, glass fibers, prepreg material, polyimide, liquid crystal polymer, epoxy-based Build-Up Film, and FR4 material.

4. The package according to claim 1, wherein the electronic component is configured for functionally cooperating with the MEMS component.

5. The package according to claim 1, wherein the MEMS component is configured as one of the group consisting of a sensor, an actuator, a loudspeaker, a balanced armature receiver, a microphone, an autofocus component, a scanner, a two-dimensional scanner, a haptic actuator, a pressure sensor, a micropump, an adjustable lens, an adjustable wavelength selective filter, and a fluid sensor.

6. The package according to claim 1, wherein the electronic component is a semiconductor chip, an application specific integrated circuit chip (ASIC).

7. The package according to claim 1, comprising bonding material at a mounting position between the support structure and the cover structure.

8. The package according to claim 7, wherein the bonding material is configured for providing both a mechanical connection and an electric coupling between the support structure and the cover structure.

9. The package according to claim 1, comprising at least one of the following features: wherein the MEMS component is mounted on the support structure (102) and/or on the cover structure; wherein at least part of lateral surfaces of the electronic component is in direct contact with material of at least one of the support structure and the cover structure; wherein at least one of the group consisting of the support structure and the cover structure comprises at least one through hole for providing fluid communication between the MEMS component and an environment of the package; wherein at least one of the group consisting of the support structure and the cover structure has an acoustic wave propagation influencing surface pattern; wherein the MEMS component is located in a cavity delimited between the support structure and the cover structure; wherein the cover structure comprises at least one of the group consisting of an electromagnetic interference protection, an electrostatic discharge protection, solder pads, and an acoustic property adjustment feature for passive filtering of acoustic waves; wherein at least part of the electrically conductive contact structure is configured for electrically coupling the electronic component with the MEMS component.

10. A method of manufacturing packages, comprising: providing a support structure which comprises an electrically insulating material; mounting a microelectromechanical system (MEMS) component, on the support structure; mounting a cover structure, which comprises an electrically insulating material, on the support structure so as to at least partially cover the MEMS component, wherein the cover structure is configured as a printed circuit board, or as a section thereof; embedding an electronic component in one of the support structure and the cover structure; and providing at least one of the support structure and the cover structure with an electrically conductive contact structure.

11. The method according to claim 10, further comprising: providing a support master structure, wherein the support structure (102) forms part of the support master structure; mounting at least one further MEMS component, on the support master structure; at least partially covering the at least one further MEMS component with a cover master structure mounted on the support master structure, wherein the cover structure forms part of the cover master structure; and embedding at least one further electronic component in at least one of the support master structure and the cover master structure.

12. The method according to claim 11, further comprising: singularizing the arrangement of the support master structure, the cover master structure, the embedded electronic components and the mounted MEMS components to thereby obtain a plurality of packages each comprising support structure, electronic component, MEMS component and cover structure.

13. The method according to claim 11, wherein the electronic components and the MEMS components are two dimensionally distributed over the support master structure and the cover master structure.

14. An arrangement, comprising: a support master structure comprising electrically insulating material; a plurality of microelectromechanical system (MEMS) components, mounted on the support master structure; comprising electrically insulating material, mounted on the support master structure and at least partially covering the MEMS components so as to define individual cavities for each of the MEMS components between a corresponding section of the support master structure and a corresponding section of the cover master structure, wherein the cover master structure is configured as a printed circuit board, or as a section thereof; and a plurality of electronic components embedded in at least one of the support master structure and the cover master structure; wherein at least one of the support master structure and the cover master structure comprises an electrically conductive contact structure.

Description

[0039] The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

[0040] FIG. 1 shows a cross-sectional view of a package according to an exemplary embodiment of the invention.

[0041] FIG. 2 shows a cross-sectional view of a package according to another exemplary embodiment of the invention.

[0042] FIG. 3 shows a cross-sectional view of a package according to yet another exemplary embodiment of the invention.

[0043] FIG. 4 shows a side view of the package of FIG. 3 on a substrate embodied as printed circuit board.

[0044] FIG. 5 shows a cover master structure (which may also be denoted as cavity panel) of an arrangement according to an exemplary embodiment of the invention.

[0045] FIG. 6 shows a support master structure (which may also be denoted as integrated circuit substrate panel) of an arrangement according to an exemplary embodiment of the invention.

[0046] FIG. 7 shows a schematic view illustrating MEMS packaging procedures carried out during a method of manufacturing packages according to another exemplary embodiment of the invention.

[0047] FIG. 8 shows a support master structure of an arrangement according to another exemplary embodiment of the invention.

[0048] FIG. 9 shows a schematic view illustrating a method of manufacturing packages according to another exemplary embodiment of the invention.

[0049] FIG. 10 shows a cover master structure of an arrangement according to another exemplary embodiment of the invention.

[0050] FIG. 11 shows a cross-sectional view of an arrangement according to an exemplary embodiment of the invention.

[0051] FIG. 12 shows a cross-sectional view of a package according to another exemplary embodiment of the invention.

[0052] FIG. 13 and FIG. 14 show cross-sectional views of packages according to exemplary embodiments of the invention.

[0053] The illustrations in the drawings are schematical. In different drawings, similar or identical elements are provided with the same reference signs.

[0054] Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the invention have been developed.

[0055] Exemplary embodiments of the invention provide a concept concerning PCB-based packaging for MEMS sensors. One or more dice/electronic components and other electronic components may be placed on a substrate (also denoted as support master structure) in strip format. The assembly can rely on die-attach, flip-chipping, wirebonding, etc. to achieve electrical and mechanical connection. A second strip made of matching cavities (also denoted cover master structure) may be aligned and attached. This procedure can rely on having the bonding material (such as solder, epoxy, etc.) placed (for instance by dispensing, stamping, printing) on the substrate strip or the cavity one. After both strips are connected, individual packages may be singulated.

[0056] In order to let a pressure wave generated by a MEMS component escape the package (in the specific case of a loudspeaker), a hole may be formed in at least one of the elements, which does not have to be straight (for instance perpendicular to the substrate), but can have a complex shape through the PCB. This structure can additionally be chamfrained in order to improve propagation.

[0057] In a bottom port architecture, the hole is located between solder pads. In a top port architecture, the hole is on the other element (not aligned with the moveable membrane to avoid damage through particulate ingress). The top-port package has a smaller footprint, but the bottom-port one has a higher sensitivity due to its larger back volume. The port does not have to be straight, but can have a complex shape through the PCB.

[0058] In particular, providing a conduit of the package (in particular in the support structure thereof) along which acoustic waves may propagate between an exterior of the package and the MEMS component (at least partially) parallel to a membrane of the MEMS component enables the creation of a balanced-armature receiver. Leaving the conduit open on one side (for example using the main substrate as closing element) allows for thinner packages, arrangements and related devices.

[0059] An additional (preferably smaller) hole may be formed in the other element (i.e. support structure or cover structure) in order to allow for the pressure to balance itself.

[0060] A cavity around the MEMS (in the specific case of a loudspeaker) is preferably configured as close to a half-sphere as possible, in order to avoid sound reflection, which might negatively affect device performance. For example, this can be achieved by drilling and/or milling with a spherical bit, or any other methods. One of the dice and some of the passives can also be embedded in one of the elements (i.e. support structure and cover structure) to reduce overall package dimensions and improve electrical performance.

[0061] For example, embodiments of the invention may provide an embedded loudspeaker and an embedded balanced-armature receiver. Exemplary embodiments of the invention can also be used for micro-mirrors and other similar actuators, microphones, pressure sensors, etc.

[0062] It is advantageous that membrane-based MEMS components are enclosed as much as possible to protect the moveable element of the MEMS component, while still allowing both the membrane to move and air to reach it. In an embodiment, this can be achieved by using a PCB-based substrate for interconnection, and preferably a further PCB-based substrate for enclosure.

[0063] Hence, an exemplary embodiment of the invention enables to create PCB-based loudspeakers and actuators, thereby dramatically increasing production scale, and reduce material and non-recurring engineering (NRE) costs. In comparison with a metal, exemplary embodiments of the invention make it possible that the top side can be functionalized or patterned, for example to create passive filtering. The manufacturing concept according to exemplary embodiments decreases production costs and enables integration of various functions.

[0064] When carrying out strip-to-strip bonding according to an exemplary embodiment, a high accuracy and a suppression of warpage can be advantageously obtained by temporarily clamping support master structure and cover master structure together during processing.

[0065] If a hermetic connection is made between the sensing element of the MEMS component and the hole (to prevent ingress, which could damage other parts of the system), the architecture would also be compatible with fluidic sensors.

[0066] An embodiment of the invention improves conventional architectures by simplifying the assembly process (by using exactly two PCBs), thereby dramatically reducing the risk of misalignment (causing yield loss) and increasing production speed. In comparison with a metal can, the top side can even be functionalized or patterned to create passive filtering. This comes in addition to the simplified assembly processes and lower NRE costs. The process changes decrease production costs.

[0067] FIG. 1 shows a cross-sectional view of a package 100 according to an exemplary embodiment of the invention. The package 100 of FIG. 1 is embodied as a loudspeaker.

[0068] The package 100 comprising a support structure 102 embodied as a section of a printed circuit board (PCB). Thus, the support structure 102 comprises FR4 as an electrically insulating material and comprises copper structures as electrically conductive contact structures 110 formed in and on the electrically insulating material. An electronic chip 104, here embodied as an ASIC, is embedded within an interior of the support structure 102 so as to be fully or entirely surrounded by material of the support structure 102. The electronic chip 104 is hence buried within the support structure 102. Correspondingly, the main surfaces and all lateral surfaces of the electronic chip 104 are covered with material of the support structure 102. As can be taken from FIG. 1, the support structure 102 is embodied as a PCB support structure in which the electronic chip 104 is buried within FR4 material of the support structure 102.

[0069] A microelectromechanical system (MEMS) component 106 which comprises an acoustic transducer membrane is surface mounted on an upper main surface of the support structure 102, directly above a through hole 112 (which may also be denoted as a vent hole) formed in the support structure 102.

[0070] A cover structure 108 which is also embodied as a section of a printed circuit board (PCB) has been processed (for instance mechanically such as by drilling or chemically such as by etching) so as to have an internal hollow cavity 114. Hence, the cover structure 108 serves as a cap. The cover structure 108 comprises FR4 as an electrically insulating material and comprises copper structures as electrically conductive contact structures 110 formed in and on the electrically insulating material. The MEMS component 106 is located in the cavity 114 which is delimited between the support structure 102 and the cover structure 108.

[0071] The cover structure 108 is mounted on the support structure 102 for covering the MEMS component 106. The fixation of the cover structure 108 on the support structure 102 is accomplished by bonding material 116 such as an adhesive. By providing an electrically conductive adhesive between sections of the electrically conductive contact structures 110 on either sides of the bonding material 116, the mechanical connection between the support structure 102 and the cover structure 108 may be performed simultaneously with the electric coupling between them. The cover structure 108 is here embodied as a PCB-type cap which accommodates the MEMS component 106 and nevertheless maintains an air-filled cavity 114.

[0072] As can be taken from FIG. 1, a bond wire 120 is foreseen so as to electrically couple the MEMS component 106 to the electronic chip 104 via the electrically conductive contact structure 110 of the support structure 102. Thus, the electrically conductive contact structure 110 contributes to an electric coupling between the electronic chip 104 and the MEMS component 106. For reproducing audio content by emitting acoustic waves by the loudspeaker type package 100 towards the environment, electric signals indicative of this audio content are supplied from the electronic chip 104 to the MEMS component 106 via the described electrically conductive connection. In another embodiment, in which the electronic chip 104 is mounted in a flip chip configuration, the bond wire 120 may be omitted, and the electric coupling of the flip chip mounted electronic chip 104 may be accomplished by solder dots or copper pillars.

[0073] Each of the support structure 102 and the cover structure 108 comprises a respective through hole 112 for providing an air communication between the MEMS component 106 and an environment of the package 100 so that acoustic waves may propagate from the MEMS component 106 to a surrounding of the package 100. An exterior portion of the through hole 112 formed in the support structure 102 is provided with a chamfering section 154 to improve the acoustic wave propagation properties between an interior and an exterior of the package 100.

[0074] In both the support structure 102 and the cover structure 108, the respective electrically conductive contact structure 110 is configured to have components 122 which are surface layers patterned in order to obtain a desired conductive structure. However, the respective electrically conductive contact structure 110 also comprises one or more vias 124 vertically extending through the respective PCB-type support structure 102/cover structure 108 and connecting layer-shaped portions of the electrically conductive contact structure 110.

[0075] The embedding of the control chip, i.e. electronic chip 104, into the PCB type support structure 102 as well as the substantially vertical arrangement of electronic chip 104 and MEMS component 106 result in a compact design of the package 100. A correspondingly achievable miniaturization is further supported by the flat plate-based architecture of both the support structure 102 and the cover structure 108. Despite of its plate shape, the cover structure 108 furthermore provides a cap function, and can be also be used for a batch-type processing together with the also plate-based support structure 102.

[0076] FIG. 2 shows a cross-sectional view of a package 100 according to another exemplary embodiment of the invention. In contrast to the package 100 of FIG. 1, the package 100 of FIG. 2 is embodied as a balanced armature receiver.

[0077] A further difference between the package 100 of FIG. 2 and the package 100 of FIG. 1 in that the lower through hole 112, serving as vent hole, is not arranged at a bottom side of the support structure 102 according to FIG. 2, but at a lateral side. Thus, according to FIG. 2, the package 100 may be attached on its bottom side to a mounting substrate (not shown, for instance a PCB) without any limitations in terms of keeping the lower through hole 112 exposed to the environment. The vent air conduit constituted by the lower through hole 112 is therefore aligned partially parallel to the membrane 160 of the MEMS component 106.

[0078] FIG. 3 shows a cross-sectional view of a package 100 according to another exemplary embodiment of the invention. The package 100 of FIG. 3 is embodied as a partially balanced armature receiver.

[0079] The package according to FIG. 3 differs from the package according to FIG. 1 and FIG. 2 in that its bottom has a step shape which allows a lower portion on the right-hand side to be used as a mounting surface while keeping the lower through hole 112 free as a consequence of the step shape.

[0080] FIG. 4 shows a cross-sectional view of the package 100 according to FIG. 3 mounted on a substrate 400 via a bonding material 402. The substrate 400 is here embodied as a printed circuit board (PCB) having an electrically insulating core 404 and an electrically conductive wiring 406 by which the substrate 400 is electrically coupled to the package 100. Hence, FIG. 4 shows a receiver on a PCB.

[0081] FIG. 5 shows a cover master structure 500 of an arrangement according to an exemplary embodiment of the invention. As can be taken from FIG. 5, the cap- and PCB-type cover master structure 500 may be manufactured on the basis of a printed circuit board substrate shown on the left-hand side of FIG. 5. On the processed printed circuit board surface as support master structure 500, a plurality of package formation sections 502 are formed which are arranged in rows and columns, i.e. in a matrix-like pattern. Between subsequent package formation sections 502, respectively inactive areas 504 are formed. In each of the package formation sections 502, a plurality of cover structures 108 are formed, in turn, in a matrix-like pattern, i.e. also in rows and columns.

[0082] FIG. 6 shows a support master structure 600 of an arrangement according to an exemplary embodiment of the invention. In a similar way as described referring to FIG. 5, the support master structure 600 also comprises a plurality of package formation sections 602 formed in rows and columns with inactive regions 604 between the respective package formation sections 602. Again, each of the package formation sections 602 comprises a plurality of the support structures 102 which are arranged as well as in rows and columns, i.e. in a matrix-like pattern. Although not shown in FIG. 6, the MEMS components 106 may be mounted on the support structure 102 shown in FIG. 6 on the through hole 112.

[0083] For manufacturing packages 100 in a batch procedure, the cover master structure 500 is attached on top of the support master structure 600 and is connected thereto by adhesive material or the like. Each package formation section 502 is thereby aligned with regard to a corresponding package formation section 602. Also the inactive regions 504, 604 are in alignment with one another. Subsequently, singularization of the so obtained arrangement (compare reference numeral 1100 in FIG. 11) into a plurality of packages 100 is carried out.

[0084] FIG. 7 shows schematically shows procedures of a method of manufacturing packages 100 according to another exemplary embodiment of the invention. In other words, FIG. 7 illustrates a part of the manufacturing procedure for manufacturing packages 100 according to an exemplary embodiment.

[0085] As can be taken from reference numeral 702, the MEMS component 106 may be connected to the support structure 102 by die bonding. As can be taken from reference numeral 704, the MEMS components 106 are then electrically connected to the electronic chip 104 by wire bonding, i.e. by formation of wire bonds 120. As can be taken from reference numeral 708, a cavity 114 for later accommodating the MEMS component 106 is then formed as part of cover structure 108. As can be furthermore taken from reference numeral 710, a strip-to-strip bonding (i.e. a connection of the cover master structure 500 of FIG. 5 and the support master structure 600 of FIG. 6) and subsequently a singularization of the so obtained arrangement into individual packages 100 is then carried out.

[0086] FIG. 8, FIG. 9 and FIG. 10 show a very similar procedure as FIG. 5 to FIG. 7, wherein FIG. 8 corresponds to FIG. 6, FIG. 9 correspond to FIG. 7 and FIG. 10 corresponds to FIG. 5. The difference between the embodiment of FIG. 8 to FIG. 10 compared to the embodiment of FIG. 5 to FIG. 7 is that is different support structures 102 and different cover structures 108 are implemented. According to FIG. 8 to FIG. 10, the respective MEMS component 106 is located directly above the electronic chip 104 rather than laterally displaced, as according to FIG. 5 to FIG. 7.

[0087] FIG. 11 shows a cross-sectional view of an arrangement 1100 according to another exemplary embodiment of the invention.

[0088] The arrangement 1100 comprises PCB based support master structure 600, a plurality of electronic chips 104 embedded in the support master structure 600, a plurality of MEMS components 106 on the support master structure 600, and PCB based cover master structure 500 mounted on the support master structure 600 and covering the MEMS components 106 so as to define individual cavities 114 for each of the MEMS components 106 between a corresponding section of the support master structure 600 and a corresponding section of the cover master structure 500. The arrangement 1100 shown in FIG. 11 shows a cross-sectional view of the individual packages 100. Along separation lines 1102, a singularization of the arrangement 1100 into the various packages 100 according to exemplary embodiments of the invention may be accomplished. This can be performed by laser cutting, sawing, etching, or the like.

[0089] FIG. 12 shows a cross-sectional view of a package 100 according to another exemplary embodiment of the invention. According to FIG. 12, the electronic chip 104 is a light-sensitive CCD (charge coupled device) chip configured for detecting image data. The CCD type electronic chip 104 is embedded in the support structure 102 and cooperates with a MEMS-type adjustable lens as MEMS component 106 being mounted above the CCD type electronic chip 104. Based on an electric control signal supplied from the CCD chip 104 to the MEMS component 106, the MEMS type lens may modify its curvature and/or position and may therefore change the optical properties of light propagating towards the CCD type electronic chip 104. In the embodiment of FIG. 12, at least a portion of the cover structure 108 above the MEMS component 106 and the electronic chip 104 should be optically transparent or should have a through hole 112 allowing light to propagate into the cavity 114.

[0090] FIG. 13 and FIG. 14 show cross-sectional views of packages 100 according to exemplary embodiments of the invention.

[0091] The package 100 shown in FIG. 13 is configured as a balanced armature receiver (BAR) having a dual sided configuration. This means that a support structure 102 with embedded electronic component 104 is covered on each of its two opposing main surfaces by a respective MEMS component 106 being, in turn, covered by a respective cover structure 108. In addition, a membrane 1300 covers an exposed surface of the respective MEMS component 106. The membrane 1300 may for instance be made of silicone or any other polymer material. Thus, a compact design can be combined with a high level of functionality. FIG. 13 furthermore shows a casing 1302 (for instance of metal or of plastic) which serves as acoustic waveguide and comprises an acoustic wave access opening 1304.

[0092] The package 100 shown in FIG. 14 is configured as a balanced armature receiver (BAR) having a single sided configuration. This means that a support structure 102 with embedded electronic component 104 is covered on only one of its two opposing main surfaces with a MEMS component 106, which is, in turn, covered by a membrane 1300 and surrounded by a cover structure 108. Also the embodiment of FIG. 14 comprises a casing 1302 which is configured correspondingly to the casing 1302 of FIG. 13.

[0093] It should be noted that the term comprising does not exclude other elements or steps and the a or an does not exclude a plurality. Also elements described in association with different embodiments may be combined.

[0094] It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.

[0095] Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants are possible which use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.