CN111295894A

CN111295894A - Microphone package

Info

Publication number: CN111295894A
Application number: CN201880071190.2A
Authority: CN
Inventors: T·K·林; J·斯泽赫; J·沃森
Original assignee: Knowles Electronics LLC
Current assignee: Knowles Electronics LLC
Priority date: 2017-09-12
Filing date: 2018-09-11
Publication date: 2020-06-16
Also published as: DE112018004658T5; WO2019055437A1

Abstract

A microphone includes a substrate defining an inlay cavity between a first surface of the substrate and an opposing second surface of the substrate, the first surface defining a first opening to the inlay cavity, a distance between the first surface and the second surface defining a substrate thickness. A cover is disposed on the first surface of the substrate and forms a housing, the cover including a port, the substrate thickness being greater than a height of the cover from the first surface of the substrate. A micro-electromechanical system (MEMS) transducer is disposed in the housing and mounted on the first surface of the substrate over the first opening, and an Integrated Circuit (IC) is disposed in the housing and electrically coupled to the MEMS transducer. The MEMS transducer and the IC are disposed in a front cavity volume of the housing defined by the cover and the substrate.

Description

Microphone package

Cross Reference to Related Applications

This application claims priority from U.S. provisional patent application No.62/557,613 entitled "micropene Package" filed on 12/9/2017. This application is also continued and claimed in priority from U.S. patent application No.15/988,983 entitled "MicrophonePackage for full Encapsulated ASIC and Wires" filed 24/5.2018, the entire contents of both of which are incorporated herein by reference. U.S. patent application No.15/988,983 claims priority from U.S. provisional patent application No.62/511,221 filed on 25/5/2017.

Background

In a microelectromechanical systems (MEMS) microphone, a MEMS die (die) includes at least one diaphragm and at least one backplate. The MEMS die is supported by a base or substrate and is enclosed by a housing (e.g., a cup with walls (cup) or a lid). The port may extend through the substrate (for a bottom port device) or through the top of the housing (for a top port device). Acoustic energy passes through the port, causing the diaphragm to move and produce a changing electrical potential of the backplate, thereby producing an electrical signal. Microphones are deployed in various types of devices, such as personal computers, cellular phones, mobile devices, headsets, and hearing aid devices.

Disclosure of Invention

In one aspect of the disclosure, a microphone includes a substrate defining an inlay cavity between a first surface of the substrate and an opposing second surface of the substrate, the first surface defining a first opening to the inlay cavity, a distance between the first surface and the second surface defining a substrate thickness. The microphone also includes a cover disposed on the first surface of the substrate and forming a housing, the cover including a port, the substrate thickness being greater than a height of the cover from the first surface of the substrate. The microphone further includes: a micro-electro-mechanical system (MEMS) transducer disposed in the housing and mounted on the first surface of the substrate over the first opening; and an Integrated Circuit (IC) disposed in the housing and electrically coupled to the MEMS transducer. The MEMS transducer and IC are disposed in a front volume of the housing, the front volume being defined by the cover and the substrate, and the port extending between the front volume and an exterior of the housing.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the following drawings and detailed description.

Drawings

The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

Fig. 1 is a cross-sectional view representation of a first example microphone apparatus according to an embodiment of the present disclosure.

Fig. 2 is a cross-sectional view representation of a second example microphone apparatus according to an embodiment of the present disclosure.

Fig. 3 is a cross-sectional view representation of a third example microphone apparatus according to an embodiment of the present disclosure.

Fig. 4A is a cross-sectional view representation of a fourth example microphone apparatus according to an embodiment of the present disclosure.

Fig. 4B illustrates an enlarged view of a portion of the fourth example microphone apparatus illustrated in fig. 4A.

Fig. 5 is a cross-sectional view representation of a fifth example microphone apparatus according to an embodiment of the present disclosure.

Fig. 6A is a top view representation of a seventh example microphone apparatus according to an embodiment of the present disclosure.

Fig. 6B illustrates an isometric view of a portion of the seventh example microphone apparatus shown in fig. 6A.

Fig. 7A is a cross-sectional view of a seventh example microphone apparatus, in accordance with embodiments of the present disclosure.

Fig. 7B depicts a top view of the seventh example microphone apparatus shown in fig. 7A.

Fig. 7C shows a cross-sectional view of the seventh example microphone apparatus shown in fig. 7A with more than one IC.

Fig. 8 illustrates a cross-sectional view of an eighth example microphone apparatus, in accordance with embodiments of the present disclosure.

Fig. 9 shows a flow diagram of an example process for manufacturing a microphone apparatus according to an embodiment of the disclosure.

Fig. 10A and 10B depict a cross-sectional view and a top view, respectively, of a ninth example microphone apparatus, in accordance with embodiments of the present disclosure.

Fig. 11 shows a flow diagram of an example process for manufacturing a microphone apparatus according to an embodiment of the disclosure.

Fig. 12 illustrates a cross-sectional view of a tenth example microphone apparatus, in accordance with embodiments of the present disclosure.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like numerals generally identify like components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

Detailed Description

This disclosure describes devices and techniques for improving the robustness of microphone devices and pressure sensing transducers, such as pressure sensing transducers incorporating micro-electromechanical system (MEMS) transducers. In some embodiments, the devices and techniques described in this disclosure improve the signal-to-noise ratio of a top-port microphone device by including an embedded cavity within the substrate. The height of the base plate may be greater than the height of the cover including the acoustic port.

In one or more embodiments, the microphone apparatus may include an encapsulation material at least partially covering the integrated circuit electrically connected to the MEMS transducer, and the lid may include a thin region over the encapsulation material. The thin region provides additional area to contain the potting material without having to increase the height of the cap or increase the front volume of the housing (discussed below) which may negatively impact electro-acoustic performance.

In one or more embodiments, the microphone apparatus may include a sealed port located below the integrated circuit. The sealed ports can help remove debris trapped in the embedding cavity of the substrate during manufacturing.

In one or more embodiments, a microphone device may include a multilayer substrate in which electrical components such as resistors and capacitors may be formed. By forming the components within the substrate rather than on the upper surface of the substrate, the overall size of the microphone apparatus can be reduced.

In one or more embodiments, a particulate filter may be located between the MEMS transducer and the opening to the embedded cavity. The particulate filter may reduce the risk of debris trapped in the embedded cavity coming into contact with the diaphragm of the MEMS transducer, thereby improving the reliability of the microphone arrangement.

In one or more embodiments, the microphone apparatus may include a cover engagement ring for engaging the cover to the substrate. The cover engagement ring may include a notch or cut-out that may be filled with an adhesive, such as epoxy, to reduce the risk of the cover separating from the substrate during manufacture or installation of the microphone apparatus.

In one or more embodiments, a microphone device includes a surface cavity that houses an integrated circuit and packaging material, thereby reducing the risk of the packaging material coming into contact with the MEMS transducer during manufacturing. In one or more embodiments, the microphone apparatus may include a platform on which the MEMS transducer can be placed so as to isolate the MEMS transducer from the packaging material.

Fig. 1 is a cross-sectional view of a first example microphone apparatus 100, in accordance with an embodiment of the present disclosure. The first example microphone apparatus 100 includes a substrate 110, a micro-electro-mechanical system (MEMS) transducer 102, a first Integrated Circuit (IC)104, a second IC106, and a lid 108. The substrate 110 includes a first surface (front surface 116) and an opposite second surface (back surface 114). The MEMS transducer 102 and the first IC104 are disposed on the front surface 116 of the substrate 110, while the second IC106 is disposed on the upper surface of the first IC 104. Wires 124 electrically connect the MEMS transducer 102 to the first IC 104. Although not shown, wires may also connect the MEMS transducer 102 to the second IC 106. Further, wires may also connect each of the MEMS transducer 102, the first IC104, and the second IC106 to the substrate 110. The MEMS transducer 102, the first IC104, the second IC106, and the substrate 110 may each include a conductive bond pad to which an end of a wire may be bonded. In some embodiments, solder may be used to bond the wires 124 to the appropriate bond pads.

A cover 108 may be attached to the front surface 116 of the substrate 110 to enclose and protect the MEMS transducer 102, the first IC104, the second IC106, and any bonding wires. The cover 108 may comprise a material such as plastic or metal. The cover 108 may define a through-hole or top port 122 extending between an outer upper surface 118 and an inner upper surface 126 of the cover 108. The cover 108 may have a cover height H defined by the distance of the outer upper surface 118 from the front surface 116 of the substrate 110_c. In some implementations, the lid height H_cMay be about 0.3mm to about 0.7mm, or about 0.4mm to about 0.6mm, or about 0.55 mm. Cover 108 may have a thickness T defined by the distance between outer upper surface 118 and inner upper surface 126_c. In some casesIn implementations, the thickness of the cover 108 may be uniform, while in other implementations, the thickness of the cover 108 may be non-uniform. The cover 108 may have a generally rectangular, circular, oval, or any polygonal shape, as viewed in a direction perpendicular to the outer upper surface 118 of the cover 108. The interior upper surface 126 of the cover 108, the interior side surface 128 of the cover 108, and the exposed portion of the front surface 116 inside the cover 108, the MEMS transducer 102, the first IC104, and the second IC106 define a front cavity volume 130. The front cavity volume 130, the diaphragm of the MEMS transducer 102, and the back cavity volume (discussed below) may contribute, in combination, to the acoustic properties of the first example microphone apparatus 100.

The substrate 110 may include, but is not limited to, a printed circuit board, a semiconductor substrate, or a combination thereof. The substrate 110 may have a substrate height H defined by the distance between the front surface 116 and the back surface 114_s. In some implementations, the height H of the substrate 110_sMay be about 0.3mm to about 1.8mm, or about 0.5mm to about 0.8mm or about 0.65 mm. In some implementations, the height H of the substrate 110_sMay be greater than height H of cover 108_c. The substrate 110 may define an embedding cavity 112 disposed between a front surface 116 and a back surface 114. The substrate 110 may also define a port 120 extending between the front surface 116 and the embedding cavity 112. The port 120 is located below the MEMS transducer 102 such that the embedded cavity 112 is in fluid communication with the diaphragm of the MEMS transducer 102. In some implementations, the substrate 110 may define one or more ports in addition to the ports 120 extending between the front surface 116 and the embedding cavity 112. Additional one or more ports, such as port 120, may provide fluid communication between the embedded cavity 112 and one or more diaphragms of the MEMS transducer 102. For example, the MEMS transducer may be a multi-motor MEMS transducer that can include two or more diaphragms. The substrate 110 may define an additional port extending between the front surface 116 and the embedded cavity 112 such that the port 120 is located below a first diaphragm and the additional port is located below a second diaphragm of the multi-motor MEMS transducer. In some implementations, additional ports (e.g., port 120) may provide fluid communication between the embedded cavity 112 and additional MEMS transducers (e.g., MEMS transducer 102). As an example, each of the MEMS transducers may comprise a single sheetA diaphragm.

The inlay cavity 112 may have a height H_cavityWidth W_cavityAnd length L_cavity(not shown). Height H of inlay Cavity 112_cavityIs less than the height H of the substrate 110_s. In some implementations, the height H of the embedding cavity 112_cavityMay be the height H of the substrate 110_sFrom about 60% to about 20%, or from about 50% to about 30%, or about 40%. In addition to the volume defined by the port 120 and the volume defined by the MEMS transducer 102 relative to the front surface 116 of the substrate 110, a back cavity volume 138 is also formed by the embedded cavity 112. The ratio of the front volume 130 to the back volume 138 can affect the acoustic characteristics of the first example microphone apparatus 100 (e.g., the signal-to-noise ratio (SNR) of the first example microphone apparatus 100). For example, decreasing the ratio of the front volume 130 to the back volume 138 may improve the SNR of the first microphone apparatus. In one or more embodiments, the ratio of the front volume 130 to the back volume 138 may vary from about 0.5 to about 3.

The MEMS transducer 102 may include a conductive diaphragm positioned in a spaced relationship from a conductive backplate. The diaphragm is configured to move relative to the backplate in response to an incident acoustic signal. Movement of the diaphragm relative to the backplate causes a change in capacitance associated with the MEMS transducer 102. The change in capacitance of the MEMS transducer 102 in response to the acoustic signal may be measured and converted to a corresponding electrical signal. The MEMS transducer 102 may include one or more diaphragms that are movable relative to one or more back plates.

The first IC104 and the second IC106 may include analog circuitry and/or digital circuitry for processing electrical signals received from the MEMS transducer 102. In one or more embodiments, the first IC104 and the second IC106 may be integrated circuit packages having a plurality of pins or bond pads that facilitate electrical connection with components external to the first IC104 and the second IC106 via wires. In particular, the first IC104 may include bond pads to which the first set of wires 124 may be connected. Bond pads may also be present on the second IC106 to connect another set of wires between the MEMS transducer 102 and the second IC 106. The analog or digital circuitry may include amplifiers, filters, analog-to-digital converters, digital signal processors, and other circuitry for processing electrical signals received from the MEMS transducer 102 and other components on the substrate 110. In some implementations, the second IC106 may include a digital signal processor, while the first IC104 may include additional circuitry. In some implementations, the second IC106 may not be present, and circuitry that would otherwise be included in the second IC106 may instead be included in the first IC 104. The first IC104 and the second IC106 may also include additional bond pads to bond wires connecting the respective ICs to conductors on the front surface 116 of the substrate 110 and to bond wires connecting the first IC104 to the second IC 106. In one or more implementations, the first IC104 and the second IC106 may have a photosensitive coating that blocks light from entering circuitry inside the IC 104. In one or more embodiments, the one or more bond pads on the first IC104, the second IC106, and the substrate 110 may be gold bond pads. The use of gold bond pads may improve corrosion resistance due to exposure to moisture and other environmental substances through the top port 122. Corrosion resistance may also be reduced by coating the bond pads with a corrosion resistant material.

Fig. 2 is a cross-sectional view of a second example microphone apparatus 200, in accordance with an embodiment of the present disclosure. The second example microphone apparatus 200 is similar in many respects to the first example microphone apparatus 100 discussed above with respect to fig. 1, and features described herein with respect to fig. 1 or similar components of other embodiments described herein may be applied to any of the corresponding components of the various embodiments, unless otherwise indicated. The second example microphone apparatus 200 also includes an encapsulation material 132 and a thin region 134. In some embodiments, the encapsulation material 132 at least partially covers the first and

second ICs

104, 106 and/or any wires (not shown) extending between the first and

second ICs

104, 106 and the substrate 110. In one or more embodiments, the encapsulation material 132 completely covers the first and

second ICs

104, 106 and/or any wires (not shown) extending between the first and

second ICs

104, 106 and the substrate 110. In one or more embodiments, the encapsulation material 132 may completely cover the first and

second ICs

104, 106 and at least partially cover any wires extending between the first and

second ICs

104, 106 and the substrate 110. The encapsulation material 132 may be a non-conductive material (such as an epoxy). One process stage during the manufacture of the second example microphone apparatus 200 may include depositing the encapsulation material 132 over the first IC104 and the second IC 106.

The encapsulation material 312 may be deposited as follows: the encapsulation material 312 at least partially covers (or in some cases completely covers) the first IC104, the second IC106, and the wires extending to the substrate 110. During deposition, the encapsulation material 132 may be in a high temperature and low viscosity state. Over time, the encapsulation material 132 cools and solidifies to form a cap layer over the first IC104, the second IC106, and the conductive lines extending to the substrate 110. In some cases, the low viscosity of the encapsulation material 132 may cause lateral stretching of the encapsulation material during deposition. In some cases where the first IC104 and the MEMS transducer 102 are disposed on the same front surface 116 of the substrate 110, lateral stretching of the encapsulation material 132 may cause the encapsulation material 132 to contact the MEMS transducer 102. This may damage or adversely affect the electro-acoustic performance of the MEMS transducer 102. In one or more embodiments, the first IC104 and the second IC106 may have a photosensitive coating that blocks light from entering circuitry inside the IC104 in addition to or instead of the encapsulation material 132. In one or more embodiments, the one or more bond pads on the first IC104, the second IC106, and the substrate 110 may be gold bond pads. The use of gold bond pads may improve corrosion resistance due to exposure to moisture and other environmental substances through the top port 122. Corrosion resistance may also be reduced by coating the bond pads with a corrosion resistant material.

To reduce the risk of damaging the MEMS transducer 102, the front surface 116 of the substrate 110 may have a cavity (not shown) formed in the front surface 116 of the substrate 110, and the first IC104, the second IC106, and the encapsulation material 132 may be partially or fully disposed within the cavity. Lateral spread of the encapsulation material 132 during and after deposition may be confined within the sidewalls of the cavities. Accordingly, the MEMS transducer 102 and other components mounted on the substrate 110 may be protected from undesired contact with the encapsulation material 132.

A thin region 134 may be formed on the cover 108 near the top port 122. The thin region 134 may include a stepped inner upper surface 136, the stepped inner upper surface 136 being stepped or recessed relative to the inner upper surface 126. Specifically, the stepped inner upper surface 136 is stepped in the direction of the outer upper surface 118. The distance between stepped inner upper surface 136 and outer upper surface 118 defines a thickness T of thin region 134_trThe thickness T_trIs less than a thickness T of cover 108 defined by a distance between inner upper surface 126 and outer upper surface 118_c. In some implementations, the thickness T of the thin region 134_trMay be the thickness T of the cover 108_cAbout 30% to about 70%, or the thickness T of the cover 108_cAbout 40% to about 60%, or the thickness T of the cover 108_cAbout 50% of the total. Thin region 134 may be formed along the periphery of top port 122. The stepped inner upper surface 136 may have a perimeter that forms at least a portion of the perimeter of the top port 122. In some implementations, the stepped inner upper surface 136 may completely surround the top port 122. In some implementations, the thin region 134 may be positioned proximate to the top port 122 such that a perimeter of the thin region 134 is separated from a perimeter of the top port 134. The shape of the perimeter of the thin region 134, as viewed in a direction perpendicular to the inner upper surface 126, may be any rectangular or irregular polygonal shape or curved shape. The reduced thickness of cover 108 at thin region 134 allows clearance without having to increase the height H of cover 108_cThereby accommodating the encapsulation material 132 disposed on the substrate 110 with the front volume 130 increased. The second example microphone apparatus 200 may also incorporate a recess in the lid 108 as well as other features of the microphone apparatus discussed in commonly owned U.S. patent application No.15/154,545, the subject matter of which is hereby incorporated by reference in its entirety.

Fig. 3 is a cross-sectional view of a third example microphone apparatus 300, in accordance with an embodiment of the present disclosure. The third example microphone apparatus 300 is similar in many respects to the second example microphone apparatus 200 discussed above with respect to fig. 2. To the extent that some features of the third example microphone apparatus 300 are similar to those of the second example microphone apparatus 200, these features are provided with the same reference numerals in both fig. 2 and 3. The third example microphone apparatus 300 also includes a sealed port 140. As discussed above, the front surface 116 defines a port 120 (and any additional ports) that extends between the front surface 116 and the embedded cavity 112 and is located below the MEMS transducer 102. The front surface 116 also defines a seal port 140 that also extends between the front surface 116 and the inlay cavity 112. However, rather than the port 120 being disposed below the MEMS transducer 102 to provide fluid communication between the diaphragm and the embedded cavity 112, the sealed port 140 is located outside the perimeter of the MEMS transducer formed on the front surface 116.

The sealed port 140 may be located, for example, below the first IC104 such that the sealed port 140 is covered by the first IC 104. In some cases, the first IC104 may be adhered to the front surface 116 of the substrate 110 using a dispensed die attach film or a preferred die attach film 142. The die attach film 142 may include an adhesive that can help bond the first IC104 to the front surface 116. In some such cases, a die attach film 142 may be used to cover and seal the sealing port 140. During manufacturing, the sealing port 140 may help remove debris deposited within the embedding cavity 112. For example, debris may be trapped in the embedding cavity 112 during formation of the embedding cavity 112 or other features of the substrate 110. If these debris is not removed from the embedded cavity 112, they may come into contact with the diaphragm of the MEMS transducer 102, thereby resulting in an increased risk of damaging the MEMS transducer 102. Forming the sealing port 140 in the substrate 110 (prior to placing the first IC104 or the die attach film 142) may help remove debris from the embedding cavity 112. For example, air may be blown through one of the port 120 and the sealed port 140 to allow debris to be dislodged via the other of the port 120 and the sealed port 140. Once the debris is removed, the first IC104 or die attach film 142 may be positioned on the front surface 116 to seal the sealing port 140. In some implementations, the port 140 can be completely sealed from the front volume 130. In some other implementations, the port 140 can be partially sealed with respect to the front volume 130. The sealed port 140 may not contribute to the acoustic characteristics of the third example microphone apparatus 300. As described above, the substrate may define one or more ports located below the MEMS transducer 102 to correspond to one or more diaphragms. In addition to one or more ports disposed below the MEMS transducer 102, a sealed port 140 may also be disposed below the first IC 104.

Fig. 4A is a cross-sectional view of a fourth example microphone apparatus 400, according to an embodiment of the present disclosure. The fourth example microphone apparatus 400 is similar in many respects to the second example microphone apparatus 200 discussed above with respect to fig. 2. To the extent some features of the third example microphone apparatus 300 are similar to those of the second example microphone apparatus 200, these features are provided with the same reference numerals in both fig. 2 and 4A. The fourth example microphone apparatus 400 includes a multilayer substrate 410. Similar to the substrate 110 shown in fig. 2, the multi-layer substrate 410 defines the embedding cavity 112 and the port 120. The multilayer substrate 410 additionally includes multiple layers of materials and electrical components (such as resistors and capacitors).

Fig. 4B illustrates an enlarged view of a portion 420 of the fourth example microphone apparatus 400 illustrated in fig. 4A. The multi-layer substrate 410 includes an upper substrate layer 430, an inner substrate layer 416, and a lower substrate layer 424. The upper substrate layer 430, the inner substrate layer 416, and the lower substrate layer 424 may include materials such as epoxy, glass-reinforced epoxy, composite fiber glass cloth with epoxy (e.g., FR4), and the like. The multilayer substrate 410 may define a plated through hole 432 that may be filled with the solder mask 408. In one or more embodiments, the plated through holes 432 can be plated with a conductive material (such as copper or aluminum). The first adhesive layer 414 may be disposed between the upper substrate layer 430 and the inner substrate layer 416, and the second adhesive layer 418 may be disposed between the inner substrate layer 416 and the lower substrate layer 424. On a side of the upper substrate layer 430 opposite to a side of the upper substrate layer 430 adjacent to the inner substrate layer 416, the upper metal layer 406 may be disposed above the upper metal layer 406. The solder mask 408 may cover at least a portion of the upper metal layer 406. On a side of the lower substrate layer 424 adjacent to the inner substrate layer 416, a lower metal layer 426 may be disposed on the lower substrate layer 424. Solder mask 408 may also cover at least a portion of lower metal layer 426. A via metal layer 434 may extend through the plated via 432 between the upper metal layer 406 and the lower metal layer 426 to form an electrical connection therebetween.

The multi-layer substrate 410 also includes a plurality of inner metal layers, such as a first inner metal layer 412 disposed between the upper substrate layer 430 and the inner substrate layer 416, and a second inner metal layer 428 and a third inner metal layer 422 disposed between the inner substrate layer 416 and the lower substrate layer 424. The second inner metal layer 428 and the third inner metal layer 422 may be separated by a dielectric layer 436. The third inner metal layer 422 may be in contact with the via metal layer 434, thereby making electrical contact with the upper metal layer 406 and the lower metal layer 426. In some implementations, the first inner metal layer 412 may serve as a ground terminal, and the second inner metal layer 428 and the third inner metal layer 422 may serve to carry electrical signals.

The multilayer substrate 410 may also include passive circuit elements such as resistors and capacitors. For example, the resistor 404 may be disposed on the same side of the upper substrate layer 430 on which the upper metal layer 406 is disposed. One end or terminal of resistor 404 may make electrical contact with upper metal layer 406. The resistor 404 may comprise a conductive material having a resistance substantially greater than the resistance of the upper metal layer 406. The multilayer substrate 410 may also include reactive circuit elements, such as a capacitor 402 disposed between the inner substrate layer 416 and the lower substrate layer 424. The capacitor 402 may include a portion of the dielectric layer 436 disposed between a portion of the second inner metal layer 428 and a portion of the third inner metal layer 422. The portion of the second inner metal layer 428 may form a first terminal of the capacitor 402 and the portion of the third inner metal layer 422 may form a second terminal of the capacitor 402. A second terminal of capacitor 402 may be coupled to the resistor via metal layer 434 and upper metal layer 406.

The locations of the resistor 404 and capacitor 402 shown in fig. 4B are examples only. The resistor 404 and capacitor 402 may also be located elsewhere within the multi-layer substrate 410. For example, the capacitor 402 may alternatively be disposed between the upper substrate layer 430 and the inner substrate layer 416, or adjacent to any of the layers of the multi-layer substrate 410. The resistor 404 may also be adjacent to any of the layers of the multi-layer substrate 410. Although not shown in fig. 4B, the multilayer substrate 410 may include additional resistors and capacitors similar to the resistor 404 and the capacitor 402 having various values. In one or more embodiments, the value of the resistor 404 or additional resistors may vary from about 10 ohms to about 100 ohms. In one or more embodiments, the resistor 404 or additional resistors may have the following dimensions: the width ranges from about 75 microns to about 150 microns and the length ranges from about 75 microns to about 300 microns. In one or more implementations, the thickness of the resistor 404 or additional resistors may be in a range from about 0.1 microns to about 1 micron. In one or more embodiments, the value of capacitor 402 or another capacitor may vary from about 10pF to about 300 pF. By forming resistors and capacitors in one or more layers of the multilayer substrate 410, these electrical components that could otherwise be disposed above the front surface 116 can now be housed within the multilayer substrate 410 itself, thereby enabling the reduction of Radio Frequency (RF) interference caused by these electrical components. In some cases, an additional benefit of housing these electrical components within the multilayer substrate 410 is that space on the front surface 116 may be freed up to accommodate other components, or to thereby enable a reduction in the overall size of the fourth example microphone apparatus 400.

Fig. 5 is a cross-sectional view of a fifth example microphone apparatus 500, in accordance with embodiments of the present disclosure. The fifth example microphone apparatus 500 is similar in many respects to the second example microphone apparatus 200 discussed above with respect to fig. 2. To the extent that some features of the fifth example microphone apparatus 500 are similar to those of the second example microphone apparatus 200, in both fig. 2 and 5, these features are provided with the same reference numerals. The fifth example microphone apparatus 500 may include a particulate filter 502 disposed adjacent to the port 120. As mentioned above with respect to the third example microphone apparatus 300 of fig. 3, the manufacturing process of the substrate may result in debris accumulation within the embedding cavity 112. This debris can increase the risk of damaging the diaphragm of the MEMS transducer 102. The particulate filter 502 reduces the risk of debris embedded in the cavity 112 coming into contact with the diaphragm of the MEMS transducer 102. The particulate filter 502 may include perforations that are sized large enough so that the particulate filter 502 does not obstruct fluid communication between the diaphragm and the embedding cavity 112 but small enough to obstruct debris embedded within the cavity 112 from contacting the diaphragm. In one or more embodiments, the particulate filter 502 may be composed of a porous ceramic having an effective pore size ranging from about 10 microns to about 20 microns and a porosity between 55% to 65%. Other pore sizes and porosities may also be selected that allow for adequate filtration of debris while maintaining acceptable acoustic permeability of the particulate filter 502. Although the particulate filter 502 is shown in fig. 5 as being disposed on one end of the port 120 adjacent to the MEMS transducer 102, the particulate filter 502 may alternatively be disposed on the opposite end of the port 120. That is, the particulate filter 502 may be positioned to cover the opening of the port 120 leading to one end of the insert cavity 112.

In some implementations, an additional particulate filter may be positioned to cover the top port 122. The top port particulate filter may reduce the risk of debris entering the front volume 130 via the top port 122. The top port particulate filter may be located below the top port 122, above the top port 122, or flush within the top port 122, such that the upper surface of the top port particulate filter is flush with the outer upper surface 118, or in the same plane as the outer upper surface 118.

Fig. 6A is a top view of a sixth example microphone apparatus 600, according to an embodiment of the present disclosure. The top view in fig. 6A is shown without the cover. Fig. 6B illustrates an isometric view of a portion of the sixth example microphone apparatus 600 shown in fig. 6A. The sixth example microphone apparatus 600 includes a substrate 610 having a front surface 616. The first IC104 and the MEMS transducer 102 are disposed on the front surface 616. The substrate 610 may be similar to the substrate 110 discussed above with respect to fig. 1. A cover engagement ring 650 is also provided on the front surface 616. The cover engagement ring 650 has a perimeter that is substantially similar to the perimeter of the cover 656 shown in fig. 6B. The cover engagement ring 650 may improve adhesion of the cover 656 to the front surface 616 of the substrate 610. The improved adhesion reduces the risk of the cover 656 peeling or separating from the substrate 610 and exposing the MEMS transducer 102, the first IC104, and other components on the front surface 616. In some implementations, the cover engagement ring 650 can include a metallic material (e.g., ferrous metal, non-ferrous metal, copper, steel, iron, silver, gold, aluminum, titanium, etc.). For example, the cap engagement ring 650 may include copper traces plated with nickel and/or gold (e.g., gold plated on a nickel plating, etc.). Such a metal cap engagement ring 650 may be welded to the front surface 616. In other embodiments, the cap engagement ring 650 may be formed from another material (e.g., a thermoplastic material, a ceramic material, etc.). In some embodiments, the cover engagement ring 650 is adhered, fused, and/or otherwise coupled to the front surface 616 (e.g., adhesively coupled to the front surface 616, etc.) without the use of solder.

To provide additional mechanical strength to the engagement between the cover 656 and the front surface 616, a bottom fill adhesive 658 is provided between the cover 656 and the front surface 616. An underfill adhesive 658 is provided in the space defined by the notch 652 (fig. 6A) formed in the cap engagement ring 650. The notch 652 includes a notch surface 660 that is stepped relative to an outer side surface 654 of the cap engagement ring 650 in a direction toward an inner side surface 662 of the cap engagement ring 650. The notch surface 660 is substantially parallel to the outer side surface 654. The length of the recess surface 660 in a direction generally perpendicular to the longitudinal axis of the cover 656 and in the plane of the front surface 616 is designated L_nAnd (4) showing. The width of the notch 652 in a direction along the longitudinal axis of the cover and in the plane of the front surface 616 is defined by W_nAnd (4) showing. Width W of the notch_nDefining a distance between the notch surface 660 and the outboard surface 654. Width W of the notch_nLess than the width W of the cap engagement ring 650_r. This allows a portion of the cover bonding ring 650 to act as a barrier and reduces the risk of underfill adhesive 658 penetrating into the portion of the microphone apparatus 600 covered by the cover 656 and damaging internal components, such as the first IC104, the MEMS transducer 102, or the bonding wires 124. Although fig. 6A and 6B illustrate a notched cover engagement ring 650 in connection with the top port design, the notched cover protection ring may also be used to engage the cover 608 to the front surface 616 of the bottom port sixth example microphone set 600 shown in fig. 6.

In some implementations, the notches 652 may be replaced by gaps, holes, cuts, or vents, resulting in inconsistencies or discontinuities in the cover engagement ring 650. During production, the MEMS transducer 102, the cover engagement ring 650, and the cover 656 may be welded or otherwise coupled to the substrate 610. After the MEMS transducer 102, the cap engagement ring 650, and the cap 656 are coupled together, an infusible adhesive or sealant in the form of epoxy or another infusible material may be applied between the substrate 610, the cap engagement ring 650, and the cap 656 to effectively seal the aperture and isolate the MEMS transducer 102 within the cap 656. The melting point of the epoxy and/or another infusible material may advantageously be higher than the solder used to couple the cover 656 and/or the cover joint ring 650 to the substrate 610 so that the epoxy or another infusible material does not melt upon reflow soldering. As a result, when the microphone apparatus 600 is subsequently melt-back welded during integration or mounting to a larger apparatus (e.g., for a smartphone, tablet, laptop, smartwatch, hearing aid, camera, communication device, etc.), the epoxy or another infusible material holds the cover 656 and/or the cover engagement ring 650 in place and does not cause the cover 656 and/or the cover engagement ring 650 to tilt, rotate, shift, or otherwise deform during the heating cycle. The sixth example microphone apparatus 600 may also incorporate other features, tags, and guard rings of the microphone apparatus as discussed in commonly owned U.S. patent application No.62/367,531, the subject matter of which is hereby incorporated by reference in its entirety.

Fig. 7A is a cross-sectional view of a seventh example microphone apparatus 700, in accordance with embodiments of the present disclosure. In particular, the seventh example microphone apparatus 700 includes a bottom port design in which the substrate 710 (rather than the cover 708) defines a bottom port 720, the bottom port 720 allowing an acoustic signal to be incident on the diaphragm of the MEMS transducer 102. The substrate 710 includes a first or front surface 716 and an opposite second or back surface 714. The MEMS transducer 102 and the first IC104 are disposed on the front surface 716. Wires 124 may extend from the MEMS transducer 102 to the first IC 104. The second set of conductive lines 125 may extend from the first IC to the substrate 710. Encapsulation material 132 is disposed over first IC104 to at least partially cover first IC104 and wires 125. In one or more embodiments, encapsulation material 132 completely covers ICs 104, while at least partially covering wires 125. The MEMS transducer 102, the first IC104, and the wire 124 are similar to the corresponding elements with similar reference numerals discussed above with respect to the first example microphone apparatus 100 shown in fig. 1. In some implementations, the seventh example microphone apparatus 700 may include a second IC (similar to the second IC106 shown in fig. 1) disposed on the first IC104 and covered with the encapsulation material 132. Additional conductive lines may extend between the second IC and the first IC104 and the substrate 710.

The substrate 710 defines a bottom port 720, the bottom port 720 including an opening extending between the front surface 716 and the back surface 714 such that an exterior of the seventh example microphone apparatus 700 is in fluid communication with the diaphragm of the MEMS transducer 102. The cover 708 is disposed over a front surface 716 of the substrate 710 and encloses the MEMS transducer 102, the first IC104, and the

wires

124 and 125. Unlike the cover 108 discussed above with respect to the first example microphone apparatus 100 shown in fig. 1, the cover 708 of the seventh example microphone apparatus 700 does not include an opening. Accordingly, the inner upper surface 726 of the cover 708, the inner side surface 728 of the cover 708, and the exposed portion of the front surface 716 inside the cover 708, the MEMS transducer 102, and the first IC104 define a back volume 732 of the seventh example microphone device 700. The seventh example microphone apparatus 700 also defines a front cavity volume 730, which is the combined volume of the space below the MEMS transducer 102 and the volume defined by the bottom port 720.

The substrate 710 may define an encapsulation material confinement structure, which may include a surface cavity 750 in the front surface 716 of the substrate 710. The surface cavity 750 may extend from the front surface 716 of the substrate 710 to the IC mounting surface 754 of the substrate 710. In the illustrated embodiment, the front surface 716 and the IC mounting surface 754 are on separate planes. In some embodiments, the front surface 716 and the IC mounting surface 754 may be in the same plane; for example, in some embodiments, the MEMS transducer 102 may be mounted on an elevated platform, such as in a manner described in further detail below, and the front surface 716 and the IC mounting surface 754 may be in the same plane. The first IC104 is located on the IC mounting surface 754 of the surface cavity 750. In some implementations, the first IC104 is mounted on the IC mounting surface 754 using a bonding material, such as solder or glue. Although not shown in fig. 1, the ASIC mounting surface may include one or more conductive bond pads to provide connections between conductive traces on the substrate and the IC 104. A second set of wires 125 connect bond pads on IC mounting surface 754 to bond pads on IC 104. In some implementations, the height H1 of the surface cavity 750 (i.e., the height from the IC mounting surface 754 to the front surface 716) can be less than the height of the IC104, such that a portion of the IC104 extends above the cavity.

The substrate 710 also includes a platform 756 (also referred to as a "MEMS mounting surface") that is raised above the front surface 716 or raised relative to the front surface 716. In the illustrated embodiment, the height H1 of the surface cavity 750 is greater than the height H2 that the platform 756 rises above the front surface 716. In some embodiments, height H2 may be greater than or equal to height H1. Platform 756 may be formed around the perimeter of surface cavity 750. In some embodiments, platform 756 may form a sidewall of surface cavity 750. In some other embodiments, the platform 756 may be separated from the surface cavity 750 by the front surface 716. The MEMS transducer 102 is mounted on the upper surface of the platform 756. The bottom port 720, as discussed above, extends through the substrate 710 at the location where the MEMS transducer 102 is mounted.

The encapsulation material 132 at least partially covers the IC104 and/or the second set of wires 125, and in some embodiments, completely covers both the IC104 and the second set of wires 125. The encapsulation material 132 may be a non-conductive material (such as an epoxy). One process stage during the manufacture of the first example microphone apparatus 100 may include depositing an encapsulation material 132 over the IC 104. The encapsulation material 312 may be deposited such that it at least partially covers (or in some cases completely covers) the IC104 and the second set of wires 125 extending from the IC104 to the substrate 710. In one or more embodiments, encapsulation material 132 completely covers ICs 104, while at least partially covering wires 125. During deposition, the encapsulation material 132 may be in a high temperature and low viscosity state. Over time, the encapsulation material 132 cools and solidifies to form a blanket layer over the ICs 104 and the second set of wires 125. However, the low viscosity of the encapsulation material 132 may cause lateral stretching of the encapsulation material during deposition. Where the IC104 and MEMS transducer 102 are disposed on the same surface of the substrate 710, lateral stretching of the encapsulation material 132 may cause the encapsulation material 132 to contact the MEMS transducer 102. This may damage the MEMS transducer 102. By placing the IC104 and the second set of wires 125 within the surface cavity 750, the lateral spread of the encapsulation material 132 during and after deposition is confined within the sidewalls of the surface cavity 750. Accordingly, the MEMS transducer 102 and other components mounted on the substrate 710 may be protected from undesired contact with the encapsulation material 132.

After the encapsulation material 132 is cured, its upper surface may form a bend (curvature) that encloses the IC104 and the second set of wires 125. In some embodiments, the height of the encapsulation material 132 may be represented by the maximum distance between a point on the upper surface of the encapsulation material 132 and the IC mounting surface 754. In some embodiments, the height of the encapsulation material 132 may be equal to or greater than the maximum distance that the second set of wires 125 or the IC104 extends from the IC mounting surface 754.

Platform 756 provides additional protection from encapsulating material 132. That is, mounting the MEMS transducer 102 on the platform 756 can further isolate the MEMS transducer 102 from the encapsulation material 132. In some embodiments, the height of platform 756 may be based on the volume of encapsulation material 132 to be deposited to at least partially cover (or in some cases completely cover) IC104 and second set of wires 125, as well as the available volume within surface cavity 750.

Fig. 7B depicts a top view of the seventh example microphone apparatus 700 shown in fig. 7A. Specifically, a top view without the cover 708 is shown. The encapsulation material 132 at least partially covers the IC104 and the second set of wires 125, the second set of wires 125 extending from the IC104 to the substrate 710. In one or more embodiments, the encapsulation material 132 completely covers the IC104 and the second set of wires 125. In one or more embodiments, encapsulation material 132 completely covers ICs 104, while at least partially covering wires 125. The platform 756 surrounds the encapsulation material 132, and in the embodiment illustrated in FIG. 7B, the encapsulation material 132 completely covers the surface cavity 750 shown in FIG. 7A. The first set of wires 124 extending between the MEMS transducer 102 and the IC104 are partially covered by the encapsulation material 132. The front surface 716 of the substrate 710 also includes a cover engagement surface 758 that facilitates engagement of the cover 708 with the substrate 710. In the illustrated embodiment, the cover engagement surface 758 is separated from the platform 756 by a portion of the front surface 716 (i.e., such that the surface transitions from the platform 756 to an interior portion of the front surface 716, then to the cover engagement surface 758, and finally to an exterior portion of the front surface 716, in front of an interior portion of the microphone apparatus 700). In some embodiments, the cover engagement surface 758 may extend to the edge of the platform 756 without the middle portion of the front surface 716. In some embodiments, the cover engagement surface 758 may be a metal surface that is capable of engaging with a metal periphery of the cover 708 using solder or glue. The platform 756 not only protects the MEMS transducer 102 from the encapsulation material 132, but also protects the cap engagement surface 758 from contact with the encapsulation material 132. This prevents any defects in bonding the cover 708 to the substrate 710 (defects that may occur if the encapsulation material 132 were to spill onto the cover bonding surface 758). In one or more embodiments, the platform 756 may not completely surround the surface cavity 750. For example, platform 756 may extend only on a side of surface cavity 750 adjacent to MEMS transducer 102. In some other embodiments, platform 756 may extend along all or part of the length of one or more sides of surface cavity 750.

Fig. 7C shows a cross-sectional view of the seventh example microphone apparatus 700 shown in fig. 7A with more than one IC. In particular, the seventh example microphone apparatus 700 shown in fig. 7C includes the first IC104 and the second IC106, both of which are at least partially covered by the encapsulation material 132. In one or more embodiments, the encapsulation material 132 completely covers the first IC104 and the second IC 106. In one or more embodiments, the encapsulation material 132 may completely cover the first and

second ICs

104, 106, while at least partially covering the second set of bonding wires 125. Although not shown in fig. 7C, the seventh example microphone apparatus 700 may include bonding wires in addition to the first set of bonding wires 124 and the second set of bonding wires 125 to form electrical connections between the MEMS transducer 102, the first IC104, the second IC106, and the substrate 710. At least one of these additional bonding wires may be at least partially covered by encapsulation material 132. The first IC104 and the second IC106 may be similar to the first IC104 and the second IC106 discussed above with respect to fig. 1A-5.

Fig. 8 illustrates a cross-sectional view of an eighth example microphone apparatus 800, in accordance with embodiments of the present disclosure. Many elements of the eighth example microphone apparatus 800 are similar to the components of the seventh example microphone apparatus 700 shown in fig. 7A and 7B. To this extent, like elements are labeled with like reference numerals. The eighth example microphone apparatus 800 does not include a platform. The substrate 802 has a surface cavity 820 formed in a front surface 822 of the substrate 802, and a lower surface of the surface cavity 820 serves as an IC mounting surface 824. The height H1' of the surface cavity 820 is greater than the height of the IC104 so that the entirety of the IC104 falls within the volume of the surface cavity 820. In some embodiments, height H1' may be equal to or greater than the height of IC 104. In other embodiments, height H1' may be less than the height of IC 104. For example, the IC104 may be higher than the height H1' of the surface cavity 820, but the difference in height may be small enough so that the encapsulation material 808 does not contact the MEMS transducer 102 and/or the cap mounting surface during deposition. By making the height of the surface cavities 820 greater than the height of the ICs 104, the risk of spilling the encapsulation material 808 during deposition may be reduced, while ensuring that the encapsulation material 808 completely covers the ICs 104 and at least a portion of the second set of wires 125. The encapsulation material 808 may be similar to the encapsulation material 132 discussed above.

The substrate 802 may also include a lid mounting surface (not shown) to facilitate bonding the lid 708 to the front surface 822 of the substrate 202. The cover mounting surface may be similar to the cover engagement surface 758 discussed above with respect to fig. 7B.

In one or more embodiments, more than one IC may be mounted within surface cavity 820. For example, more than one IC may be located side-by-side within surface cavity 820. In another example, more than one IC may be stacked on top of each other. In yet another example, more than one IC may be stacked on top of each other and disposed side-by-side within the surface cavity 820. Encapsulation material 808 may be deposited in surface cavity 820 such that the encapsulation material at least partially covers (or, in some cases, completely covers) the one or more ICs regardless of the manner in which the one or more ICs are disposed within surface cavity 820.

As discussed above with respect to fig. 7A-8, the

encapsulation material

132 and 808 at least partially covers the IC104 and the second set of wires 125. In one or more embodiments, the encapsulation material may completely cover the IC104 and the second set of wires 125. In one or more embodiments, the encapsulation material 132 may completely cover the IC104, while only partially covering the second set of wires 125. The second set of conductors 125 may also be completely covered. By covering the IC104 and the second set of wires 125 within the

encapsulation material

132 or 808, the effect of the radio frequency signals generated by the IC104 and the second set of wires 125 on the MEMS transducer 102 and other components mounted on the

substrate

710 or 802 may be reduced. In some implementations, partially or completely covering the IC104 in the encapsulation material and partially or completely covering the wires in the encapsulation material can result in significant noise reduction in the microphone apparatus as compared to a microphone apparatus that does not include encapsulation material or only partially encapsulates the IC. By reducing radio frequency interference, the noise level of the electrical signals generated by the MEMS transducer 102 and other components on the

substrates

710 and 802 may be reduced. In some embodiments, a microphone device having an encapsulation completely covering the IC achieves an improvement in noise attenuation of about-15 dB compared to a microphone device without the encapsulation. Where the microphone device includes more than one IC (such as when two ICs are stacked on top of each other), the

encapsulation material

132 or 808 may cover all of the ICs and the wires connecting the ICs to the substrate, in whole or in part.

Fig. 9 shows a flow diagram of an example process 900 for manufacturing a microphone apparatus according to an embodiment of the disclosure. Process 900 includes providing a substrate (stage 902), forming a surface cavity on a front surface of the substrate (stage 904), mounting a MEMS transducer on the substrate (stage 906), mounting an IC or IC mounting surface in the surface cavity (stage 908), mounting a first set of bonding wires between the IC and the MEMS transducer and a second set of wires between the IC and the substrate (stage 910), and depositing an encapsulation material into the surface cavity to at least partially cover (or in some cases completely cover) the IC and the second set of wires (stage 912). It should be noted that the order of the stages described herein is provided by way of example only, and the present disclosure is not limited to any particular order of performing the stages. For example, in some embodiments, the MEMS transducer may be installed prior to the IC being installed, while in other embodiments, the IC may be installed prior to the MEMS transducer being installed.

Process 900 includes providing a substrate (stage 902). As discussed above with respect to fig. 7A-8, the substrate may comprise a printed circuit board or a semiconductor material. In some embodiments, the substrate may be similar to substrate 710 or substrate 802 shown in fig. 7A-8. The substrate may comprise a single or multi-layer printed circuit board, wherein each layer may comprise a set of conductive traces separated by an insulator. The conductive traces may be patterned based on the positional connections of components such as the MEMS transducer and IC to be mounted on the substrate.

Process 900 also includes creating a surface cavity on the front surface of the substrate (stage 904). One example implementation of this stage of the process is discussed above with respect to fig. 7A through 8. A surface cavity 750 is created on the front surface 716 of the substrate 710. In another example, as shown in fig. 8, a surface cavity 820 is formed on a front surface 822 of the substrate 802. In some embodiments, the cavity in the front surface of the substrate may be created using one or more of chemical etching, photolithographic routing, stamping or blanking through the substrate layers, and the like. The bottom of the cavity may form an IC mounting surface for mounting an IC. The IC mounting surface may include one or more bond pads that may be connected to bond pads on the IC using wire bonds. In some embodiments, process 900 may also include forming a ledge or platform adjacent to the surface cavity. One example of such a platform is discussed above with respect to fig. 7A-8. In one or more embodiments, the mesa may be formed by etching a surface of the substrate around a desired location of the mesa. In some other embodiments, the platform may be formed by depositing additional layers of the substrate at desired locations of the platform. In one or more embodiments, the substrate and the platform may be formed of the same material. In one or more embodiments, the substrate and the platform may be formed of different materials. For example, materials used to form the substrate and the platform may include materials such as fiberglass, epoxy, and solder masks.

The process 900 also includes mounting the MEMS transducer on the front surface of the substrate (stage 906), and mounting the IC on the IC mounting surface (stage 908). Example implementations of these process stages are discussed above with respect to fig. 7A through 8. For example, as shown in fig. 7A-8, the MEMS transducer 102 is mounted on a

substrate

710 or 802, and the IC104 is mounted on an

IC mounting surface

754 or 824. The MEMS transducer 102 and IC104 may be mounted manually or by machine (e.g., using a "pick and place machine"). In some embodiments, flip chip technology may also be used to mount the MEMS transducer 102 and the IC 104.

Process 900 also includes mounting a first set of bonding wires between the IC and the MEMS transducer and mounting a second set of bonding wires between the IC and the substrate (stage 910). Examples of implementations of this stage of the process are discussed above with respect to fig. 7A through 8. For example, a first set of wires 124 is mounted to electrically connect the MEMS transducer 102 to the IC 104. A second set of wires 125 is mounted to electrically connect the IC104 to conductive traces on the substrate 710. The first set of wires 124 and the second set of wires 125 may include a conductive material (such as aluminum, copper, silver, gold, etc.). The wires may be mounted using techniques such as ball bonding and wedge bonding.

Process 900 additionally includes depositing an encapsulation material into the surface cavity to at least partially cover the IC and the second set of wires (stage 912). Examples of implementations of this stage of the process are discussed above with respect to fig. 7A through 8. For example, as shown in fig. 7A and 8, the encapsulation material 132 at least partially or completely covers the IC104 and the second set of wires 125. Similarly, as shown in fig. 8, encapsulation material 808 at least partially or completely covers IC104 and second set of wires 125. In some embodiments, the encapsulation material may be an epoxy or a material such as a resin, polymer, glass, plastic, or the like. Prior to deposition, the encapsulation material may be heated to a predetermined temperature to allow the encapsulation material to flow. A heated epoxy may be deposited in the surface cavity such that the epoxy at least partially covers (or in some cases completely covers) the IC and a second set of wires connecting the IC to the substrate. The sidewalls of the surface cavity confine the encapsulation material within the cavity during deposition and reduce the risk of the encapsulation material coming into contact with the MEMS transducer or other components on the substrate. With respect to the flow within the surface cavity, the deposited encapsulation material may be given a period of time to stabilize to a steady state. Additional packaging material may be added if in a steady state, a portion of the IC or the second set of wires remains exposed. The encapsulating material may then be cooled until it solidifies.

It should be noted that the process stages in the process 900 depicted in fig. 9 may be performed in a different order than that shown in fig. 9. For example, mounting the IC in the surface cavity (stage 908) may be performed before mounting the MEMS transducer on the substrate (stage 906). Furthermore, mounting wires between the IC and the MEMS transducer and between the IC and the substrate (stage 910) may be performed in any order.

Fig. 10A and 10B depict a cross-sectional view and a top view, respectively, of a ninth example microphone apparatus 1000, in accordance with embodiments of the present disclosure. In the ninth example microphone apparatus 1000 shown in fig. 10A and 10B, the encapsulating material confinement structure includes a surface cavity 1020 formed by a wall 1026, the wall 1026 rising or protruding above the front surface 1022 of the substrate 1002. The upper surface 1040 of the wall 1026 is located at a height H5 above the front surface 1022 of the substrate 1002. Height H5 may be greater than, equal to, or less than the height of IC 104. The periphery 1042 of wall 1026 defines the edge of surface cavity 1020. The IC104 is mounted on a mounting surface 1024 that is part of the front surface 1022 of the substrate 1002. The MEMS transducer 102 is also mounted on the front surface 1022 of the substrate 1002. Thus, the IC104 and MEMS transducer 102 are mounted on coplanar surface portions of the substrate 1002.

Encapsulation material 1008 is deposited within surface cavity 1020 and at least partially covers IC104 and at least partially covers second set of leads 125. In one or more embodiments, the encapsulation material 1008 completely covers the IC104 and the second set of wires 125. In one or more embodiments, the encapsulation material 1008 completely covers the IC104 while at least partially covering the second set of wires 125.

The walls 1026 may completely surround a portion of the front surface 1022 of the substrate 1002 and the IC 104. In one or more embodiments, the wall 1026 can be discontinuous. In one or more embodiments, the walls 1026 may not completely surround the ICs 104. For example, walls 1026 may extend between MEMS transducer 102 and IC104 to reduce the risk of encapsulation material 1008 coming into contact with MEMS transducer 102 during and after deposition. In one or more embodiments, the wall 1026 may be incorporated into the seventh and eighth

example microphone devices

700, 800 discussed above with respect to fig. 7A-8. In some embodiments, the upper surface 1040 can be considered the upper or front surface of the substrate, such that the cavity is formed partially or entirely as an area surrounded by the wall 1026. In some implementations, the ninth example microphone apparatus 1000 may include an IC other than the IC 104. In some such implementations, the encapsulation material 1008 may partially or completely cover all of the ICs and the wires connecting the ICs to the substrate 1002.

Fig. 11 shows a flow diagram of an example process 1100 for manufacturing a microphone apparatus according to an embodiment of the disclosure. In particular, in some implementations, the process 1100 may be used to manufacture the third example microphone apparatus discussed above with respect to fig. 10A and 10B. The process 1100 includes: providing a substrate forming a wall on the substantially front surface, wherein the wall forms a surface cavity (stage 1102); mounting a MEMS transducer on a substrate (stage 1104); mounting an IC or IC mounting surface in the surface cavity (stage 1106); mounting a first set of bonding wires between the IC and the MEMS transducer and mounting a second set of wires between the IC and the substrate (stage 1108); and depositing an encapsulation material in the surface cavity to at least partially cover (or in some cases completely cover) the IC and the second set of wires (stage 1110).

Process 1100 includes providing a substrate, forming a wall on a front surface of the substrate, wherein the wall forms a surface cavity (stage 1102). In the example of this stage of the process discussed above with respect to fig. 10A and 10B, where the wall 1026 forms the surface cavity 1020 on the substrate 1002. In one or more embodiments, the walls 1026 can be formed of the same material as the substrate. For example, the walls may be formed by depositing an additional layer of substrate material. In one or more embodiments, the walls may be formed using a solder mask, a solder stop mask, or a solder resist. Multiple layers of solder masks may be deposited around the IC in a desired pattern to form the walls. Stages 1104 to 1110 may be performed in a similar manner as discussed above with respect to stages 906 to 912. It should be noted that the order of the stages described herein is provided by way of example only, and the present disclosure is not limited to any particular order of performing the stages. For example, in some embodiments, the MEMS transducer may be installed prior to the IC being installed, while in other embodiments, the IC may be installed prior to the MEMS transducer being installed.

Various example embodiments discussed herein may provide many advantages over existing designs, such as embedded substrate IC packages. In such a package, the IC is completely surrounded by the substrate material and embedded inside the substrate during the manufacturing process of the substrate. However, embedding the IC inside the substrate increases the overall cost of the microphone device. For example, a defect in a substrate may cause a good IC embedded in the defective substrate to be discarded along with the defective substrate. Furthermore, since additional lead time is required to embed the IC in the substrate, there is an increased burden in the design stage, i.e., the design of the IC and the substrate is completed early in the manufacturing process. In addition, an inventory (inventory) of ICs is maintained within the substrate. On the other hand, since the IC is packaged after the substrate is manufactured, the various embodiments discussed herein allow the microphone apparatus to be manufactured using established substrate and semiconductor processes. Furthermore, no IC inventory is maintained during the fabrication of the substrate. This reduces the complexity of the manufacturing process of the packaged IC and shortens the time to market.

Fig. 12 shows a cross-sectional view of a tenth example microphone apparatus 1200. The tenth example microphone apparatus 1200 is similar in many respects to the second example microphone apparatus 200 discussed above with respect to fig. 2. To some extent, some features of the tenth example microphone apparatus 1200 are similar to those of the second example microphone apparatus 200, and in both fig. 2 and 12, these features are provided with the same reference numerals. The tenth example microphone apparatus 1200 includes at least one wall 1226 on the front surface 116 of the substrate between the MEMS transducer 102 and the first and

second ICs

104 and 106. The wall 1226 may be similar to the wall 1026 discussed above with respect to the ninth example microphone apparatus 1000 shown in fig. 10A and 10B, and may define the surface cavity 1220. In one or more embodiments, the walls 1226 may be discontinuous and may be disposed only between the MEMS transducer 102 and the first and

second ICs

104 and 106.

While the above discussion describes various embodiments, each having various features, it should be understood that features described in one embodiment may be incorporated into other embodiments as well. For example, the first example microphone apparatus 100 shown in fig. 1 may include one or more features of each of the example microphone apparatuses discussed with respect to fig. 2-12. For example, the first example microphone apparatus 100 may include, but is not limited to, one or more of: encapsulation material 132 (fig. 2), thin region 134 (fig. 2), sealed port 140 (fig. 3), die attach film 142 (fig. 3), multilayer substrate 410 (fig. 4A and 4B), particulate filter (also referred to as "particulate barrier") 502, cover engagement ring 650 with recess 652 (fig. 6A and 6B), surface cavity 750 (fig. 7A), surface cavity 820 (fig. 8), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The second example microphone apparatus 200 shown in fig. 2 may include one or more features of each of the example microphone apparatuses discussed with respect to fig. 1, 3-12. For example, the second example microphone apparatus 200 may include, but is not limited to, one or more of the following: seal port 140 (fig. 3), die attach film 142 (fig. 3), multilayer substrate 410 (fig. 4A and 4B), particulate filter 502, cover engagement ring 650 with recess 652 (fig. 6A and 6B), surface cavity 750 (fig. 7A), surface cavity 820 (fig. 8), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The third example microphone apparatus 300 shown in fig. 3 may include one or more features of each of the example microphone apparatuses discussed above with respect to fig. 1-2, 4-12. For example, the third example microphone apparatus 300 may include, but is not limited to, one or more of the following: multi-layer substrate 410 (fig. 4A and 4B), particulate filter 502, cover engagement ring 650 with recess 652 (fig. 6A and 6B), surface cavity 750 (fig. 7A), surface cavity 820 (fig. 8), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The fourth example microphone apparatus 400 illustrated in fig. 4A and 4B may include one or more features of each of the example microphone apparatuses discussed above with respect to fig. 1-3, 5-12. For example, the fourth example microphone apparatus 400 may include, but is not limited to, one or more of the following: die attach film 142 (fig. 3), particulate filter 502 (fig. 5), cover engagement ring 650 with recess 652 (fig. 6A and 6B), surface cavity 750 (fig. 7A), surface cavity 820 (fig. 8), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The fifth example microphone apparatus 500 shown in fig. 5 may include one or more features of each of the example microphone apparatuses discussed above with respect to fig. 1-4B, 6A-12. For example, the fifth example microphone apparatus 500 may include, but is not limited to, one or more of the following: the sealed port 140 (fig. 3), the die attach film 142 (fig. 3), the multilayer substrate 410 (fig. 4A and 4B), the cover engagement ring 650 with the recess 652 (fig. 6A and 6B), the surface cavity 750 (fig. 7A), the surface cavity 820 (fig. 8), the wall 1026 (fig. 10A), and the wall 1226 (fig. 12).

The sixth example microphone apparatus 600 illustrated in fig. 6A and 6B may include one or more features of each of the example microphone apparatuses discussed above with respect to fig. 1-5, 7A-12. For example, the sixth example microphone apparatus 600 may include, but is not limited to, one or more of the following: encapsulation material 132 (fig. 2), thin region 134 (fig. 2), sealed port 140 (fig. 3), die attach film 142 (fig. 3), multilayer substrate 410 (fig. 4A and 4B), particulate filter 502 (fig. 5), surface cavity 750 (fig. 7A), surface cavity 820 (fig. 8), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The seventh example microphone apparatus 700 shown in fig. 7A-7C may include one or more features of each of the example microphone apparatuses discussed above with respect to fig. 1-6B, 8-12. For example, the seventh example microphone apparatus 700 may include, but is not limited to, one or more of the following: die attach film 142 (fig. 3), multilayer substrate 410 (fig. 4A and 4B), particulate filter 502 (fig. 5), cover engagement ring 650 with recess 652 (fig. 6A and 6B), surface cavity 820 (fig. 8), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The eighth example microphone apparatus 800 shown in fig. 8 may include one or more features of each of the example microphone apparatuses discussed above with respect to fig. 1-7C, 9-12. For example, the eighth example microphone apparatus 800 may include, but is not limited to, one or more of the following: die attach film 142 (fig. 3), multilayer substrate 410 (fig. 4A and 4B), particulate filter 502 (fig. 5), cover engagement ring 650 with recess 652 (fig. 6A and 6B), plurality of ICs 104 and 106 (fig. 7C), surface cavity 750 (fig. 7A), wall 1026 (fig. 10A), and wall 1226 (fig. 12).

The ninth example microphone apparatus 1000 illustrated in fig. 10A and 10B may include one or more features of each of the example microphone apparatuses discussed with respect to fig. 1-9 and 12. For example, the ninth example microphone apparatus 1000 may include, but is not limited to, one or more of the following: the die attach film 142 (fig. 3), the multilayer substrate 410 (fig. 4A and 4B), the particulate filter 502 (fig. 5), the cover engagement ring 650 (fig. 6A and 6B) having a recess 652, the plurality of ICs 104 and 106 (fig. 7C), the surface cavity 750 (fig. 7A), and the surface cavity 820 (fig. 8).

The tenth example microphone apparatus 1200 shown in fig. 12 may include one or more features of each of the example microphone apparatuses discussed with respect to fig. 1-11. For example, the tenth example microphone apparatus 1200 may include, but is not limited to, one or more of the following: the seal port 140 (fig. 3), the die attach film 142 (fig. 3), the multilayer substrate 410 (fig. 4A and 4B), the particulate filter 502, the cover engagement ring 650 with the recess 652 (fig. 6A and 6B), the surface cavity 750 (fig. 7A), and the surface cavity 820 (fig. 8).

The subject matter described herein sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected," or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably coupled," to each other to achieve the desired functionality. Specific examples of operatively coupled include, but are not limited to, physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

With respect to the use of plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. Various singular/plural permutations may be expressly set forth herein for the sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.).

It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations).

Further, in those instances where a convention analogous to "at least one of A, B and C, etc." is used, such a construction is generally intended in the sense one having skill in the art would understand the meaning of the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B and C together, etc.). In those instances where a convention analogous to "A, B or at least one of C, etc." is used, such a construction is generally intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B or C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B and C together, etc.). It will be further understood by those within the art that, in fact, any extracted word and/or phrase presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both of the terms. For example, the phrase "a or B" will be understood to include the possibility of "a" or "B" or "a and B". Moreover, unless otherwise specified, the use of the words "approximately," "about," "approximately," and the like, means plus or minus ten percent.

The foregoing description of the exemplary embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to be limited to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the following claims and their equivalents.

Claims

1. A microphone, the microphone comprising:

a substrate defining an embedding cavity between a first surface of the substrate and an opposing second surface of the substrate, the first surface defining a first opening to the embedding cavity, a distance between the first surface and the second surface defining a substrate thickness;

a cover disposed on the first surface of the substrate and forming a housing, the cover including a port, the substrate thickness being greater than a height of the cover from the first surface of the substrate;

a micro-electro-mechanical system (MEMS) transducer disposed in the housing and mounted on the first surface of the substrate over the first opening; and

an Integrated Circuit (IC) disposed in the housing and electrically coupled to the MEMS transducer,

the MEMS transducer and the IC are disposed in a front cavity volume of the housing, the front cavity volume defined by the cover and the substrate,

wherein the port extends between the front volume and an exterior of the housing.

2. The microphone of claim 1, wherein the cover comprises a thin region having a thickness less than a thickness of other portions of the cover.

3. The microphone of claim 2, wherein the thin region is disposed adjacent to a periphery of the port.

4. The microphone of claim 1, the first surface of the substrate defining a second opening to the inlay cavity.

5. The microphone of claim 4, the second opening being located below the IC.

6. The microphone of claim 4, the MEMS transducer being a multi-motor transducer, the first opening being located below a first diaphragm of the MEMS transducer and the second opening being located below a second diaphragm of the MEMS transducer.

7. The microphone of claim 1, further comprising: a cap engagement ring disposed on the first surface, the cap engagement ring defining a recess, the cap disposed on the cap engagement ring; and an underfill adhesive in the recess that secures the lid to the substrate.

8. The microphone of claim 1, further comprising a particulate filter covering the first opening.

9. The microphone of claim 1, further comprising a passive circuit element embedded in the substrate.

10. The microphone of claim 9, wherein the passive circuit element is reactive.

11. The microphone of claim 9, wherein the passive circuit elements comprise resistors and capacitors.

12. The microphone of claim 11, wherein the capacitor and the resistor are formed from layers embedded in the substrate.

13. The microphone of claim 1, further comprising an encapsulation material at least partially covering the IC.

14. The microphone of claim 13, further comprising an encapsulation material confinement structure disposed between the MEMS transducer and the IC, wherein the encapsulation material confinement structure at least partially confines the encapsulation material around the IC.

15. The microphone of claim 14, the substrate defining a cavity, the cavity including an IC mounting surface on which the IC is mounted, the wall portion of the cavity forming the encapsulation material confinement structure, the MEMS transducer being mounted on a MEMS mounting surface of the substrate, the MEMS mounting surface being elevated relative to the IC mounting surface.

16. The microphone of claim 15, wherein the cover is mounted on a cover mounting surface of the substrate, the MEMS mounting surface is elevated relative to the cover mounting surface, and the cover mounting surface is elevated relative to the IC mounting surface.

17. The microphone of claim 15, wherein the MEMS mounting surface is a platform that completely surrounds a periphery of the cavity.

18. The microphone of claim 14, the first surface of the substrate defining a second opening to the inlay cavity.

19. The microphone of claim 14, further comprising a resistor and a capacitor formed from layers embedded in the substrate.

20. The microphone of claim 13, the MEMS transducer and the IC being mounted on a coplanar surface portion of the substrate, the encapsulation material confinement structure being a wall portion protruding on the coplanar surface portion of the substrate, wherein the encapsulation material is at least partially confined by the wall portion.