Patent Application
20240425363
This application claims the benefit of European Patent Application No. 23180420, filed on Jun. 20, 2023, which application is hereby incorporated herein by reference.
Embodiments of the present disclosure relate to housed electronic components, and in particular to a combined sound transducer and pressure sensor package.
MEMS pressure sensors and MEMS sound transducers are an integral part of nowadays consumer electronics. For example, smartphones, tablets, smart watches, and the like, are usually equipped with one or more sound transducers, such as microphones and speakers, and with pressure sensors, such as environmental barometric pressure sensors for determining an altitude or the like. In addition, these consumer devices comprise an ever-increasing amount of additional integrated electronic components in order to satisfy the consumers' increasing needs and desires for additional features. At the same time, however, the size and form factor of the devices tends to decrease. Thus, there is a trade-off between an increase of electronic components and a decrease of available assembly space.
In some instances, assembly space inside a casing of an electronic device may be highly limited, such that manufacturers of integrated electronic components need to find new solutions for installing their components into small-sized devices. One of the challenging tasks is to properly fit MEMS pressure sensors and MEMS sound transducers into one common casing of a consumer electronics device, since these MEMS components need additional space for fluid channels for communicating with the environment.
For example, sound transducers and pressure sensors need their own fluid channels, for allowing pressure and sound waves to enter the casing. Thus, one physical channel connected with the MEMS pressure sensor and one additional physical channel connected with the MEMS sound transducer has to be provided. At the same time, two physical entry ports/openings have to be provided in the casing which increases the risk of undesired ingress of moisture, dust, environmental particles and the like. Some manufacturers provide so-called flex brackets, which act as internal port dividers inside the casing, such that only one physical port (opening) needs to be provided in the casing.
Furthermore, a MEMS pressure sensor and a MEMS sound transducer are each housed inside individual packages. Of course, this does not only increase costs, but it also consumes the already limited available assembly space inside the device's casing. Thus, some manufacturers combined a MEMS pressure sensor and a MEMS sound transducer into one common package, which led to very bulky packages.
Furthermore, in order to allow fluid to enter the respective package, each package has to comprise a fluid port/opening connected to the above-mentioned fluid channel. A combined sensor package may have the advantage that only one fluid port has to be provided. However, a MEMS sound transducer shall be mounted such that it covers the fluid port in order to provide a large back volume increasing the sound transducer's overall performance. Accordingly, the MEMS sound transducer is mounted in front of the MEMS pressure sensor in the fluid path. Since the membrane of the MEMS sound transducer attenuates the arriving pressure waves, this may lead to faulty pressure sensing by the subsequently arranged pressure sensor.
A further advantage of combined sensor packages may be the possibility of a joint package connection, i.e. both the MEMS pressure sensor and the MEMS sound transducer may be electrically connected via package pads being provided at an exterior of the common package. However, as it may be dictated by the limited available assembly space inside a casing, such packages may sometimes need to be installed such that their fluid opening is positioned opposite to the package pads. Accordingly, the package pads and the fluid opening have to be positioned on two opposite sides of the package, which can be a challenging task.
Thus, it would be desirable to provide a combined MEMS sound transducer and MEMS pressure sensor package without the above-mentioned drawbacks.
In accordance with an embodiment, a sound transducer and pressure sensor package comprises a plane substrate and a first lid being attached to a first substrate surface, wherein a first cavity is defined between the first lid and the first substrate surface, and wherein the first lid comprises a fluid opening for allowing a fluid to enter the first cavity. The package further comprises a second lid being attached to an opposite second substrate surface, wherein a second cavity is defined between the second lid and the second substrate surface. The substrate comprises a through hole for providing a fluid communication between the first and second cavities. A MEMS sound transducer is arranged inside one of the first and second cavities, the MEMS sound transducer covering the through hole. A MEMS pressure sensor is arranged inside the other one of the first and second cavities, the MEMS pressure sensor being spaced apart from the through hole. The package comprises one or more package pads for electrically contacting the MEMS sound transducer and the MEMS pressure sensor from outside the package. The one or more package pads and the fluid opening located in the first lid are positioned at two opposite sides of the package. According to the herein described innovative concept, a transfer block is arranged at the second substrate surface, wherein the transfer block is configured to provide an electric path between the one or more package pads and the MEMS sound transducer and the MEMS pressure sensor. The transfer block may be provided as a discrete component separate from the substrate.
In the following, embodiments of the present disclosure are described in more detail with reference to the figures, in which:
Equal or equivalent elements or elements with equal or equivalent functionality are denoted in the following description by equal or equivalent reference numerals.
Method steps which are depicted by means of a block diagram and which are described with reference to the block diagram may also be executed in an order different from the depicted and/or described order. Furthermore, method steps concerning a particular feature of a device may be replaceable with the feature of the device, and the other way around.
Embodiments of the present disclosure relate to housed electronic components, and in particular to microstructured MEMS (Micro Electro Mechanical System) pressure sensors, such as environmental pressure sensors, and to microstructured MEMS sound transducers, such as microphones or speakers. In particular, the herein described innovative concept is concerned with a combined sound transducer and pressure sensor package, in which a MEMS pressure transducer and a MEMS sound transducer are commonly housed.
The package 100 comprises a plane substrate 110 and a first lid 120 being attached to a first substrate surface 111, wherein a first cavity 130 is defined between the first lid 120 and the first substrate surface 111.
The package 100 further comprises a second lid 220 being attached to an opposite second substrate surface 112, wherein a second cavity 230 is defined between the second lid 220 and the second substrate surface 112. The second lid 220 comprises a fluid opening 240 for allowing a fluid to enter the second cavity 230.
Optionally, an environmental barrier structure 280 may be arranged in or at the fluid opening 240 that is provided in the second lid 220. The environmental barrier structure 280 may serve the purpose of avoiding undesired ingress of environmental dust, moisture, liquids, solid particles, and the like. The environmental barrier structure 280 may be configured as a rigid mesh or as a compliant/flexible membrane. The environmental barrier structure 280 is an optional feature that may be optionally provided in every embodiment discussed herein.
Further optionally, a mechanical stop 281 may be arranged in the fluid opening 240 that is provided in the second lid 220. The mechanical stop 281 may be provided downstream of the environmental barrier structure 280, with regards to a fluid path, in which a fluid enters the second cavity 230. The mechanical stop 281 is configured to limit an amount of deflection of the environmental barrier structure 280. For example, in case the environmental barrier structure 280 may be provided as a flexible membrane, the mechanical stop 281 may avoid undesired over-bending of the environmental barrier structure 280 in that the deflected environmental barrier structure 280 may bump against the mechanical stop 281.
The substrate 110 comprises a through hole 140 for providing a fluid communication between the first and second cavities 130, 230. According to this non-limiting exemplary embodiment, a MEMS sound transducer 150 is arranged inside the first cavity 130. The MEMS sound transducer 150 is mounted at the first substrate surface 111 such that it covers the through hole 140. The substrate 110 itself may be cavity-less, i.e. the substrate 110 itself may comprise no further cavities except from the through hole 140.
A MEMS pressure sensor 250 is arranged inside the second cavity 230 formed by the second lid 220. The MEMS pressure sensor 250 is mounted at the second substrate surface 112 such that it is laterally spaced apart from the through hole 140 in the substrate 110.
The package 100 further comprises one or more package pads 160 for electrically contacting the MEMS sound transducer 150 and the MEMS pressure sensor 250 from outside the package 100. The one or more package pads 160 and the fluid opening 240 in the second lid 220 are positioned at two opposite sides 101, 102 of the package 100.
A rigid transfer block 180 is arranged at the first substrate surface 111. The transfer block 180 is configured to provide an electric path between the one or more package pads 160 and the MEMS sound transducer 150 and the MEMS pressure sensor 250. The transfer block 180 is provided as a discrete component separate from the substrate 110. According to this non-limiting exemplary embodiment, the transfer block 180 is arranged inside the first cavity 130.
The package pad 160 for externally contacting the package 100 may be arranged at the transfer block 180. For example, the first lid 120 may comprise a hole 128 being provided at the first side 101 of the package 100. The hole 128 may be configured to accommodate an accommodating portion 175 of the transfer block 180. The accommodating portion 175 may be a protruding portion that protrudes from an upper surface of the transfer block 180. The upper surface may be the surface of the transfer block 180 that faces the first lid 120. The accommodating portion 175 may comprise a smaller width/diameter than the rest of the transfer block 180.
The hole 128 provided in the first lid 120 may be wider than a width of the accommodating portion 175 of the transfer block 180, such that the transfer block 180 is accommodated in the hole 128 by a clearance-fit. A clearance between the accommodating portion 175 and the hole 128 may be filled with bonding material 129, in particular with non-conductive bonding material, such as glue. For example, the non-conductive bonding material 129 may be permanently elastic, such that it is elastic prior to and after curing. For example, the bonding material 129 may comprise a permanently elastic soft glue. Alternatively, the non-conductive bonding material 129 may be temporarily elastic, such that it is elastic prior to curing but non-elastic after curing. For example, the bonding material 129 may comprise solder, which is solid at room temperature, but viscous/flexible at a certain reflow temperature.
For example, the rigid transfer block 180 may be fixedly secured to one of the first substrate surface 111 and the first lid 120, while being (at least temporarily, e.g. during assembly) flexibly secured to the other one of the first substrate surface 111 and the first lid 120. In the exemplary embodiment shown in
The plane substrate 110 may be configured as a rigid substrate. For example, the plane substrate 110 may be configured as a laminated printed circuit board (PCB). The plane substrate 110 may comprise a routed wiring comprising one or more wiring structures for electrically connecting the transfer block 180, the MEMS sound transducer 150 and the MEMS pressure sensor 250 with each other. The routed wiring of the substrate 110 may comprise at least one of one or more conductive surface pads 126, one or more conductive surface traces 125, and one or more integrated conducting layers 124 for providing the above mentioned electric path between the externally contactable package pad 160 and any electronic components residing inside the package 100, such as the MEMS sound transducer 150 and the MEMS pressure sensor 250.
The transfer block 180 may also be rigid. For example, the transfer block 180 may be made from the same or a similar material as the substrate 110, e.g. from a PCB-material. The transfer block 180 may comprise one or more external electric conductors (not explicitly shown) being routed vertically along its outer circumference, and/or one or more internal electric conductors (not explicitly shown) being routed through the inside of the transfer block 180. The one or more electric conductors may provide a conductive path between a first side of the transfer block 180 facing the first lid 120 and an opposite second side of the transfer block 180 facing the first substrate surface 111. For example, one or more electric conductors may provide a conductive path between the package pad 160 and a wiring structure 126 of the substrate 110.
Optionally, a first controlling circuitry 190 for controlling the MEMS sound transducer 150 may reside inside the first cavity 130, for example adjacent to the MEMS sound transducer 150 on the same substrate surface 111. The MEMS sound transducer 150 may be coupled to the first controlling circuitry 190 by means of flexible conductors 121, e.g. by bond wires. As exemplarily depicted in
Further optionally, a second controlling circuitry 290 for controlling the MEMS pressure sensor 250 may reside inside the second cavity 230, for example between the MEMS pressure sensor 250 and the second substrate surface 112. The MEMS pressure sensor 250 may be coupled to the second controlling circuitry 290 by means of flexible conductors 221, e.g. by bond wires. As exemplarily depicted in
Further optionally, additional passive electronic devices, such as resistors, capacitors and inductors may be provided inside at least one of the first and second cavities 130, 230. For example, one or more integrated passive devices (IPD) 291 can be mounted at one of the first and second substrate surfaces 111, 112.
As exemplarily shown in
According to the present innovative concept, the MEMS sound transducer 150 and the MEMS pressure sensor 250 are both contained in one common package 100. This package 100 may have a small footprint, since the MEMS sound transducer 150 and the MEMS pressure sensor 250 are arranged on opposite substrate surfaces 111, 112. Fluid from the environment, such as environmental air, may enter the second cavity 230 through the fluid opening 240 provided in the second lid 220. Inside the second cavity 230, the fluid pressure may be sensed by the MEMS pressure sensor 250. The controlling circuitry 290 may create corresponding electric signals that may be routed through the substrate's wiring structures 124, 125, 126 via the transfer block 180 to the externally contactable package pad 160.
The fluid may then flow through the through hole 140 in the substrate 110 where it impinges the membrane 151 of the MEMS sound transducer 150. The membrane 151 may oscillate in response to the impinging sound waves, wherein the controlling circuitry 190 may create corresponding electric signals that may be routed through the substrate's wiring structures 124, 125, 126 via the transfer block 180 to the externally contactable package pad 160.
It may be advantageous to arrange the MEMS sound transducer 150 and the MEMS pressure sensor 250 in the way as discussed with reference to
According to
In other words, the MEMS sound transducer 150 is mounted at the second substrate surface 112 such that it covers the through hole 140. The MEMS pressure sensor 250 is arranged at the first substrate surface 111, being laterally spaced apart from the through hole 140.
This embodiment may be advantageous since the first control circuitry 190 for controlling the MEMS sound transducer 150 may be arranged on the opposite substrate surface than the MEMS sound transducer 150 itself. For example, the MEMS sound transducer 150 may be mounted at the second substrate surface 112, while the first control circuitry 190 may be mounted at the first substrate surface 111. The MEMS sound transducer 150 and the first control circuitry 190 may be coupled to each other via the wiring structures 124, 125, 126 of the substrate 110. This embodiment may save assembly space inside the package 100.
Alternatively, the first control circuit 190 may be arranged at the second substrate surface 112, as schematically indicated by means of the first control circuit 190′ being drawn in dashed lines. In this case, additional assembly space for integrating further components may be available at the first substrate surface 111.
According to
This embodiment may be advantageous since additional assembly space for integrating further components may be available at both the first and second substrate surfaces 111, 112. Moreover, both the MEMS sound transducer 150 and the MEMS pressure sensor 250 may be arranged on the same substrate surface 111, 112.
Furthermore, as exemplarily depicted in
According to
As exemplarily depicted in
The component board 210 may be configured as a plane and rigid substrate. A height of the transfer block 180 and a height of the first lid 120 may be substantially the same. That means, the height of the transfer block 180 may deviate from the height of the first lid 120 by less than ±20%, or less than ±10%. Accordingly, the component board 210 may rest at an exterior surface of the first lid 120, in particular at an exterior surface that faces away from the substrate 110. Thus, the innovative package 100 may be directly mounted onto the component board 210, such that the first lid 120 is in direct contact with the component board 210, which significantly reduces the assembly space needed for installing the package 100. Accordingly, a height of the mounted package 100 can be significantly reduced even though the fluid opening 240 and the package pads 160 are positioned at two opposite sides of the package 100.
The component board 210 may comprise wiring structures (not explicitly shown) as previously discussed with respect to the substrate 110, e.g. conductive surface pads and/or conductive traces and/or integrated conductive layers. Via the wiring structures, a conductive path between the component board 210 and the transfer block 180 may be established, with the one or more package pads 160 sitting between the transfer block 180 and the component board 210 in the conductive path.
The transfer block 180 may comprise one or more internal and/or external electric conductors 181 being routed vertically along its outer circumference or through the inside of the transfer block 180, respectively. The one or more electric conductors 181 may provide a conductive path between the substrate 110 and the component board 210.
For example, the electric conductors 181 may provide a conductive path between the component board 210 and a wiring structure 124, 125, 126 of the substrate 110. Via the wiring structure 124, 125, 126 of the substrate 110, the MEMS sound transducer 150 and the MEMS pressure sensor 250 may be coupled to the transfer block 180 as described above. Accordingly, an electric path may be provided between at least one of the package pad 160 and the transfer block 180 and the MEMS sound transducer 150 and the MEMS pressure sensor 250, even though the transfer block 180 may be arranged outside the package 100.
In addition, a transfer block 180 as previously discussed with reference to the previous Figures may be provided inside the first cavity 130. In this case, the package pads 160 protruding from the first lid 120 may be connected to a wiring structure of the component board 210.
According to the embodiment shown in
In comparison with
The embodiment as shown in
A component board 210 may be arranged at an exterior surface of the first lid 120, in particular at an exterior surface that faces away from the substrate 110. The transfer block 180 and the further transfer block 180′ may be arranged between the substrate 110 and the component board 210.
Each one of the transfer blocks 180, 180′ may comprise one or more of the previously discussed package pads 160 (not visible here) for electrically contacting the MEMS sound transducer 150 and the MEMS pressure sensor 250 from outside the package 100. In particular, the one or more package pads 160 may be arranged between the respective transfer block 180, 180′ and the component board 210. The component board 210 may be mechanically and/or electrically connected to the transfer blocks 180, 180′, e.g. by means of the one or more package pads 160 being arranged at the respective transfer block 180, 180′.
The further transfer block 180′ may comprise one or more internal and/or external electric conductors 181′ being routed vertically along its outer circumference or through the inside of the further transfer block 180′, respectively. The one or more electric conductors 181′ of the further transfer block 180′ may provide a conductive path between the substrate 110 and the component board 210.
For example, the electric conductors 181′ may provide a conductive path between the component board 210 and a wiring structure 124, 125, 126 of the substrate 110. Via the wiring structure 124, 125, 126 of the substrate 110, the MEMS sound transducer 150 and the MEMS pressure sensor 250 may be coupled to at least one of the transfer block 180 and the further transfer block 180′, as described above. Accordingly, an electric path may be provided between at least one of the package pads 160 and one of the transfer blocks 180, 180′ and the MEMS sound transducer 150 and the MEMS pressure sensor 250, even though the transfer blocks 180, 180′ may be arranged outside the package 100.
In the embodiment of
The arrangement as depicted in
According to
In addition to the previously discussed embodiments, the package according to
An interior of the shell 320 may be filled with a flexible pressure transmitting material 330, the flexible pressure transmitting material encapsulating the MEMS pressure sensor 250. The shell 320 may comprise an opening 340 being in fluid communication with the fluid opening 240 provided in the second lid 220, such that a fluid entering the second cavity 230 through the fluid opening 240 contacts the flexible pressure transmitting material 330 for transmitting the fluid pressure towards the MEMS pressure sensor 250. The opening 340 may be provided at a side of the shell 320 that faces away from the second substrate surface 112.
The shell 320 may comprise an outer diameter that is smaller than an inner diameter of the second lid 220. Accordingly, some clearance between the shell 320 and the second lid 220 may remain which may provide for a fluid path 350 allowing fluid to flow into the direction of the through hole 140 provided in the substrate 110. Thus, fluid that enters the second cavity 230 through the fluid opening 240 may stream past the shell 320 so as to arrive at the through hole 140 and, thus, at the subsequently arranged MEMS sound transducer 150.
Optionally, an environmental barrier structure 282 may be arranged between the MEMS sound transducer 150 and the first substrate surface 111, wherein the environmental barrier structure 282 may cover the through hole 140. Additionally or alternatively, an environmental barrier structure 282 may be arranged at the opposite second substrate surface 112, wherein the environmental barrier structure 282 may cover the through hole 140 from the opposite second side. The environmental barrier structure 282 may be provided alternatively or in combination with the previously discussed environmental barrier structure 280.
The environmental barrier structure 282 may be provided in each and every embodiment as discussed herein. Furthermore, the shell 320 may be combined with each and every embodiment as discussed herein. It is to be noted that all embodiments discussed herein are not to be considered as isolated embodiments. Instead, all embodiments may be combined with each other, wherein all features comprising the same reference numerals may be interchanged with each other.
Although some aspects have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.
While this disclosure has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of this disclosure, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23180420 | Jun 2023 | EP | regional |
