Side-ported MEMS microphone assembly

A side-ported MEMS microphone package defines an acoustic path from a side of the package substrate to a microphone die disposed within a chamber defined by the substrate and a lid attached to the substrate. Optionally or alternatively, a circuit board, to which the microphone package is mounted, may define an acoustic path from an edge of the circuit board to a location under the microphone package, adjacent a bottom port on the microphone package. In either case, the acoustic path may be a hollow passage through at least a portion of the substrate or the circuit board. The passage may be defined by holes, channels, notches, etc. defined in each of several layers of a laminated substrate or circuit board, or the passage may be defined by holes drilled, molded or otherwise formed in a solid or laminated substrate or circuit board.

TECHNICAL FIELD

The present invention relates to microelectromechanical systems (MEMS) microphone packages and, more particularly, to side-ported MEMS microphone packages and related methods.

BACKGROUND ART

A typical microelectromechanical systems (MEMS) microphone package includes a substrate, such as an FR-4 based printed circuit board (PCB), a MEMS microphone die attached to the substrate and a cup-shaped lid or cover that is attached to the substrate to create a chamber, within which the microphone die is protected from environmental insults. The lid or the substrate defines an aperture, through which sound enters the chamber. For example, the substrate may define a through-hole under the microphone die. The microphone die detects the sound and generates corresponding electrical signals. In some implementations, other dies are co-located with the microphone die within the chamber, such as to process the electrical signals generated by the microphone die. The package typically includes electrical contact pads on the bottom surface of the substrate, by which the package can be mechanically and electrically connected to a circuit board, such as by solder or electrically conductive adhesive.

MEMS microphones are commonly used in mobile telephones, laptop computers, voice recorders and other electronic devices. These devices are typically made by placing printed circuit boards inside plastic housings. Often, the housings include user interface buttons or thin membranes, with which users may actuate electrical switches mounted on the printed circuit boards. The housings usually define ports (holes) adjacent the MEMS microphone packages, so the users' speech may enter the housing and be detected by the microphones.

Ergonomic considerations typically lead to microphone ports being located on thin sides, rather than on broad flat surfaces, of the electronic devices. For example, on a mobile telephone, the microphone port is typically located on the thin lower side of the telephone, near the bottom row of dial buttons. Because the main circuit board of the mobile telephone is co-planar with the front of the telephone, i.e., with the plane of the dial buttons, the MEMS microphone package is mounted on a differently oriented auxiliary circuit board (a “daughter board”), so as to orient the aperture of the MEMS microphone package in line with the port, i.e., along an axis that is parallel to the main circuit board.

The height of the resulting structure (i.e., the MEMS microphone package and daughter board) poses problems, because the electronic device must be thick enough to accommodate the height of the structure within the device housing. Demand for ever thinner mobile telephones and other electronic devices translates into a demand for a lower profile solution to mounting MEMS microphone packages on circuit boards.

U.S. Pat. No. 6,781,231 to Minervini, which is hereby incorporated by reference, discloses a MEMS microphone package in which an aperture is defined in a side of the microphone package lid. When the resulting side-ported MEMS microphone package is mounted on a main circuit board of a mobile telephone, the axis of the microphone package aperture is oriented in line with the telephone housing microphone port, and the MEMS microphone package presents a low profile. However, defining apertures in the sides of package lids is difficult and expensive and poses other problems.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a side-ported microphone package. The package may include a substrate and a lid attached to a first surface of the substrate to define a chamber therebetween. A microphone die may be disposed within the chamber. The substrate may at least partially define an acoustic path from outside the chamber to the microphone die, such that at least a portion of the acoustic path defined by the substrate is oriented other than perpendicular to the first surface of the substrate. For example, the at least a portion of the defined acoustic path may be oriented parallel to the first surface of the substrate.

The substrate may define an aperture in the first surface within a boundary defined by a locus of points where the lid is attached to the substrate. The substrate may also define an opening on a surface of the substrate and outside the boundary. The substrate may further define a hollow passage in communication with the aperture and with the opening, such that the passage, the aperture and the opening form at least a portion of the defined acoustic path.

The opening may be defined by a surface of the substrate that is substantially perpendicular to the first surface or by the first surface.

The substrate may include a second surface on substantially an opposite side of the substrate from the first surface. None or at least a portion of the passage may be open at the second surface.

The second surface may include a solderable portion configured into an open shape, which extends from a location proximate an edge of the substrate to another location proximate the same or a different edge of the substrate. The solderable portion may substantially bound the open portion of the passage between the solderable portion and the edge of the substrate. The solderable portion may be U shaped, with ends of the U shape proximate the edge of the substrate.

The substrate may include a laminate. A first layer of the laminate may define the aperture, and a second layer of the laminate may define at least a portion of the passage.

The aperture may be adjacent to, and in line with, a receiver portion of the microphone die. The microphone die may be disposed between the aperture and the chamber. The aperture may be in communication with the chamber.

The substrate may include a printed circuit board, ceramic and/or plastic. The substrate may include at least one wall, and the lid may be attached to the at least one wall.

Another embodiment of the present invention provides a side-ported microphone package that includes a substrate having a first surface and a second surface. The second surface is on substantially an opposite side of the substrate from the first surface. The microphone package also includes a lid attached to the first surface of the substrate to define a chamber therebetween. A microphone die may be disposed within the chamber. The second surface defines an opening. The substrate at least partially defines an acoustic path between the opening and the microphone die. The second surface comprises a solderable portion configured into an open shape that extends from a location proximate an edge of the substrate to another location proximate the same edge or a different edge of the substrate. The solderable portion substantially bounds the opening between the solderable portion and the edge of the substrate. However, the solderable portion does not surround the opening. The solderable portion may be U shaped, with ends of the U shape proximate the edge of the substrate.

Yet another embodiment of the present invention provides a side-ported microphone package that includes a substrate and a lid attached to the substrate to define a chamber therebetween. A microphone die may be disposed within the chamber. The substrate defines a sound input port in communication with the microphone die. The sound input port is oriented substantially perpendicular to the microphone die.

Another embodiment of the present invention provides a side-ported microphone package that includes a substrate having a top surface, a bottom surface and an end surface. The end surface defines an opening. A lid is attached to the substrate to define a chamber therebetween. A microphone die may be disposed within the chamber. The substrate defines at least a portion of an acoustic path from the opening to the microphone die.

An embodiment of the present invention provides a kit of parts for assembling a side-ported microphone package. The kit includes a first layer, a second layer, at least one wall and a lid. The first layer defines a hollow channel or notch in a surface of the first layer. The channel or notch extends from an edge of the first layer and terminates at a location away from any edge of the first layer. The second layer defines a bore. When the first and second layers are assembled in registration with each other, the bore is in communication with the channel or notch of the first layer. When the at least one wall is attached to the second layer in registration therewith, the bore in the second layer is in communication with a volume defined by the at least one wall.

The first layer and the second layer may each include a printed circuit board, ceramic, plastic and/or another material. Optionally or alternatively, the lid may include a printed circuit board.

Yet another embodiment of the present invention provides a method for producing a side-ported microphone package. A microphone die is disposed, relative to a substrate. A lid is attached to a first surface of the substrate to define a chamber within which the microphone die is, or will be, disposed. At least a portion of an acoustic path is defined from outside the chamber, through at least a portion of the substrate, to an aperture defined by the first surface. The aperture is within a boundary defined by a locus of points where the lid is, or will be, attached to the substrate. At least a portion of the defined acoustic path is oriented other than perpendicular to the first surface of the substrate.

A plurality of layers of the substrate may be laminated to define the at least a portion of the acoustic path. A first layer of the substrate may define the first aperture, and a second layer of the substrate may define at least a portion of the acoustic path.

The at least a portion of the acoustic path may be defined, at least in part, by boring at least one hole at least partially through the substrate. Optionally or alternatively, the at least a portion of the acoustic path may be defined, at least in part, by defining an opening in a second surface of the substrate that is substantially perpendicular to the first surface, so the opening is in communication with the acoustic path. Optionally or alternatively, the at least a portion of the acoustic path may be defined, at least in part, by defining an opening in the first surface, the opening being in communication with the acoustic path. Optionally or alternatively, the at least a portion of the acoustic path may be defined, at least in part, by defining an opening in a second surface of the substrate, the second surface being on substantially an opposite side of the substrate from the first surface, the opening being in communication with the acoustic path

Optionally or alternatively, a solderable portion may be provided on the second surface. The solderable portion may be configured into an open shape. The solderable portion may extend from a location proximate an edge of the substrate to another location proximate the same or a different edge of the substrate. The solderable portion may substantially bound the opening between the solderable portion and the edge of the substrate.

The solderable portion may be U shaped, with ends of the U shape proximate the edge of the substrate.

another embodiment of the present invention provides a method for producing a side-ported microphone assembly. A bottom side of a bottom-ported microphone package is attached to a surface of a circuit board. An opening is defined in the surface of the circuit board adjacent a present or expected future location of the bottom port of the microphone package. A hollow acoustic path is defined from a side of the circuit board, through at least a portion of the circuit board, to the opening.

The acoustic path may be defined by laminating a plurality of layers of the circuit board. A first layer of the circuit board defines the opening, and a second layer of the circuit board defines at least a portion of a hollow passage in communication with the opening and extending to the side of the circuit board.

The acoustic path may be defined by boring at least one hole at least partially through the circuit board. The hole may be in communication with the opening.

Optionally, a solderable portion may be provided on the surface of the circuit board. The solderable portion may be configured into an open shape. The solderable portion may extend from a location proximate an edge of the circuit board to another location proximate the same or a different edge of the circuit board. The solderable portion may substantially bound the opening between the solderable portion and the edge of the circuit board.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In accordance with embodiments of the present invention, methods and apparatus are disclosed for providing side-ported microphone packages and side-ported microphone assemblies. The substrate of a microelectromechanical systems (MEMS) microphone package may at least partially define an acoustic path from a side of the substrate to a microphone die disposed within a chamber defined by the substrate and a lid attached to the substrate. The acoustic path may be a hollow passage through at least a portion of the substrate. Optionally or alternatively, a circuit board, to which the MEMS microphone package is mounted, may define an acoustic path, such as via a hollow passage, from an edge of the circuit board to a location under the MEMS microphone package, adjacent a bottom port on the microphone package.

Traditionally, a port in a MEMS microphone package is defined in the lid, which is typically at least partially made of electrically conductive metal, so as to protect the microphone die and other circuits inside the package from electrical noise. Alternatively, a traditional MEMS microphone package defines a bottom port, i.e., a hole through the substrate of the package, directly under the microphone die. Both designs suffer from various problems. For example, use of a bottom-ported MEMS microphone package creates the daughter board and structure height problems described above. On the other hand, conventional side-ported packages, with ports in the sides of their lids, can lead to degraded audio quality, due to the audio response characteristics of the chamber, through which sound must travel before reaching the microphone die. These and other shortcomings are overcome by the packages and methods disclosed herein.

Surprisingly, it has been found that a MEMS microphone die can be effectively acoustically coupled to a microphone port on an electronic device, at least in part, via an acoustic path defined within a substrate of a MEMS microphone package. One would not have expected sound to propagate well through such a path, in part due to the sharp angle or tortuous geometry of such a path.

As noted, mobile telephones and other electronic devices use MEMS microphones. These electronic devices provide contexts in which the present inventions may be practiced. One exemplary context, a mobile telephone, will now be described.FIG. 1is a perspective view of a mobile telephone100,FIG. 2is a cross-sectional view of a portion of the mobile telephone100, andFIG. 3is a more detailed perspective view of a portion of the inside of the mobile telephone100. The mobile telephone100includes a housing104that is typically of a “clam shell” design, i.e., the housing104is made of a front half200and a back half204that snap together or are adhered or welded together. The mobile telephone100typically includes a set of dial buttons108, which is implemented as a thin membrane208, by which a user may actuate electrical switches (typified by switch210) mounted on a main circuit board214disposed within the housing104, i.e., between the front half200and the back half204of the housing104.

The housing104defines a microphone port110, i.e., a hole through which sound enters the housing104. A MEMS microphone package210is attached to the circuit board214near an edge of the circuit board214, preferably adjacent the microphone port110. The microphone package210defines an input aperture218, through which sound enters the microphone package210. The MEMS microphone package210should be positioned such that the aperture218is close to, and oriented toward, the microphone port110. Optionally, a resilient material, an adhesive or Another suitable material forms a gasket220between the inside of the housing104and the microphone package210and/or the circuit board214, so as to create a relatively sealed acoustic path from the microphone port110to the input aperture218.

As noted, markets demand ever thinner electronic devices. Thus, there is a need for thin (as measured by thickness114) mobile telephones. A side-ported MEMS microphone package, such as the package210, facilitates meeting this need, because the microphone package210may be mounted on, and parallel to, the main circuit board214, without the need for a daughter board or other arrangement for orienting a lid port or a bottom port of the microphone package towards the microphone port110of the mobile telephone100. Furthermore, a MEMS microphone package210having an input aperture218on the side of the package substrate, rather than on the side of the lid (as in the prior art), facilitates locating the microphone package input port218as close as desired to the edge of the circuit board214, thus closer to the microphone port110of the mobile telephone housing104than is possible with prior art microphone packages. Optionally, the MEMS microphone package210may be mounted so as to partially overhang the edge of the circuit board214, thereby locating the input port218even closer to the microphone port110of the housing104.

Several exemplary embodiments of the present invention will now be described.FIG. 4is a perspective view of an exemplary side-ported MEMS microphone package210. The package210includes a substrate400and a lid404attached to one surface408of the substrate400to define a chamber therebetween. The lid404may be attached to the substrate400by solder, brazing, adhesive or any other suitable material or method. In some embodiments, the lid is cup shaped. A MEMS microphone die414(shown in phantom) is disposed in the chamber. Another surface410of the substrate400defines the input aperture218. A hollow passage provides at least part of an acoustic path from the input aperture218to the microphone die414, as described in more detail below. Although the passage is described as “hollow,” a mechanical filter may be fitted in all or part of the passage to prevent moisture or particles of contaminant from entering the chamber. An acoustic path with such a filter is nevertheless considered “hollow.”

Because the input aperture218is oriented perpendicular to the typical orientation of the MEMS microphone die414, the acoustic path should include a bend or angle to direct sound propagating along the acoustic path toward the microphone die414. The acoustic path may be formed in various ways, examples of which will now be described.

According to some embodiments, the substrate400is laminated, i.e., formed by uniting a plurality of layers of material together. The acoustic path may be defined by a set of passages formed by holes, notches, cuts, channels or other openings in some or all of the layers of the substrate400. In other embodiments, the substrate400is solid, and the acoustic path may be formed by holes channels, notches, etc., bored, molded or otherwise formed in the substrate400. Exemplary embodiments will be described with reference to cross-sectional views of variations of microphone package210, taken according to section plane B-B inFIG. 4.

FIG. 5is a cross-sectional view of an exemplary MEMS microphone package210that includes a laminated substrate400. The substrate400shown inFIG. 5includes three layers500,504and508. However, other numbers of layers may be used. As noted, the lid404is attached to one surface408of the substrate400by solder or adhesive510, or another suitable material or method, to define a chamber514. The MEMS microphone die414(shown as a solid block for simplicity) may be attached to the surface408of the substrate400, as shown inFIG. 5. Alternatively, the microphone die414may be attached to the underside518of the lid404, or the microphone die414may be otherwise disposed within the chamber514. Optionally, other circuits, such as an application-specific integrated circuit (ASIC)520may be included in the chamber514and may be connected to the microphone die414by wire bonds524or other suitable electrical connections, such as to process signals generated by the microphone die414. The substrate400defines an acoustic path528through at least a portion of the substrate400, from the input aperture218to the microphone die414.

FIG. 6is a plan view of a portion of the top layer500of the substrate400. The top layer500defines a hole600therethrough. Thus, the top layer500defines an aperture in the top surface408of the finished substrate400. The hole600is positioned on the layer500such that, when the microphone die414is attached to the substrate400, the hole600is in communication with a receiver portion (not shown) of the microphone die414, i.e., the hole is locate and oriented such that an acoustic signal exiting the hole enters the receiver portion of the microphone die414, although the acoustic signal may pass through a portion of the chamber514before reaching the receiving portion of the microphone die414. The hole600may be centered under the receiver portion of the microphone die414, as indicated by center line530. AlthoughFIG. 5shows no gap between the microphone die414and the substrate400, a gap may be present due, for example, to the thickness of solder, adhesive or other material used to attach the microphone die414to the substrate400, or due to other structures (not shown) that may be disposed between the microphone die414and the substrate400.

FIG. 7is a plan view of a portion of the middle layer504of the substrate400. The middle layer504defines a notch700that extends to a side704of the layer504. The notch700is positioned on the layer504such that, when the top layer500and the middle layer504are laminated together, the hole600(FIG. 6) in the top layer500registers with, or at least partially overlaps, a portion708of the notch700to form part of the acoustic path528. Another portion710of the notch700forms all or part of the input aperture218.

When the bottom layer508is laminated to the middle layer504, the bottom layer508seals the bottom portion of the acoustic path528. Other numbers of layers may be used. For example, several layers similar or identical to the top layer500may be laminated together to obtain a desired thickness, strength or for another reason. For example, as shown inFIG. 5, Insert A, multiple layers500a,500band500c, each defining a hole, but at staggered locations, may be laminated together to form a curved or slanted portion of the acoustic path528. Similarly, multiple layers similar or identical to the middle layer504may be laminated together, and multiple bottom layers, similar or identical to the bottom layer508, may be laminated together. Although one right-angled acoustic path528is shown inFIG. 5, any number of, or shape, acoustic path(s) may be formed by an appropriate combination of layers with appropriate holes, holes formed at angles, notches, etc. Furthermore, although a right angle transition534is shown between the hole600in the top layer and the notch700in the middle layer, the transition may be angled (as shown inFIG. 5, Insert B), curved or have another shape.

Returning toFIG. 5, it can be seen that the sound input port218is oriented horizontally, i.e., substantially perpendicular to the vertical orientation (as indicated by the center line530) of the receiver portion of the microphone die414. Furthermore, the lid404and the microphone die414are attached to the top surface408of the substrate400, while an end surface532(which may also be referred to as a “side surface”) defines the sound input port218(which may also be referred to as an “opening”).

During manufacture, the substrates400should be singulated by laser dicing, by breaking sheets of substrates along score lines or by some other dry method, rather than cutting the substrate sheets with a water-cooled/lubricated saw, to avoid water infiltration into the microphone package210, such as through the sound input port218.

In the embodiment shown inFIGS. 5 and 6, the portion of the acoustic path528defined by the substrate400terminates under the microphone die414. Alternatively, as shown inFIG. 8, the portion of the acoustic path528defined by the substrate400may terminate in the chamber514, but spaced away from the microphone die414. In this case, the top and middle layers500and504of the substrate are similar to corresponding layers described above, with respect toFIGS. 5-7, although the location of the hole600and of the portion708of the notch700do not necessarily coincide with the location of the microphone die414. In the embodiment shown inFIG. 8, a portion800of the acoustic path528extends through the chamber514. This portion800of the acoustic path528is not defined by the substrate400. In addition, the receiver portion of the microphone die414may be located at or near the top of the microphone die414. Some MEMS microphone dies can receive acoustic signals through both ends.

Other numbers of layers, and other configurations of the various layers, may also be used. For example,FIGS. 9 and 10illustrate another embodiment of the microphone package210, in which the substrate400includes at least two layers900and904. The top layer900is similar to the top layer500shown inFIGS. 5,6and8. However, the bottom layer904has a channel1000, rather than a notch700that extends through the entire thickness of the layer904, as in the embodiment described with reference toFIG. 7. (A “channel,” as used herein, has a bottom portion, as opposed to a “notch,” which is open through, from top to bottom.) Such a channel1000obviates the need for a separate bottom layer508, although the bottom layer904may need to be thicker than a separate bottom layer508. As shown inFIG. 9, the acoustic path528may terminate under the microphone die414. Alternatively, the hole and the channel1000of the substrate400may be located so the acoustic path528terminates elsewhere under the lid404, as described above, with respect toFIG. 8.

FIGS. 11 and 12illustrate yet another embodiment of the microphone package210, in which the acoustic path528is formed, such as by drilling, into a solid or laminated substrate400. For example, a first hole1100may be drilled partially or completely (as shown in phantom1104) through the substrate400. A second hole1108may be drilled to intersect with the first hole1100. If the first hole1100is drilled all the way through the substrate400, the aperture defined in the bottom surface1110of the substrate400may be left open and later blocked by a circuit board, to which the microphone package210is attached. Alternatively, the aperture may be blocked by applying an adhesive film or tape (shown in phantom1114) to a portion of the bottom surface1110. As discussed above, in other embodiments, the first hole1100is located so it is not under the microphone die414. Optionally or alternatively, the holes1100and1108may be formed as part of an injection molding, punching or other process.

As noted above, if a portion of the acoustic path528is open at the bottom of the microphone package210, the opening may be blocked by an adhesive film or by a circuit board, to which the microphone package210is attached. In yet another embodiment shown inFIGS. 13,14,15,16and17, a circuit board is used to form a wall of the acoustic path528. As best seen inFIG. 14, the bottom portion of the substrate400defines an open channel1400in communication with a hole1404that is in communication with a microphone die (not visible). The channel1400, the hole1404and other portions of the acoustic path528may be formed by drilling, routing, molding, laminating layers or another process, as described above. The acoustic path528may terminate under the microphone die414or elsewhere, as described above.

As best seen inFIG. 15, when the microphone package210is attached to a circuit board1500, the open bottom portion of the channel1400is blocked by the circuit board1500. As noted, the microphone package210may be attached to the circuit board by solder, an adhesive, or by any other suitable material or method. As best seen inFIG. 14, the bottom surface1408of the substrate400may include a solderable portion1410that follows the outline shape of the channel1400. The solderable portion1410should be configured into an open shape, such as a “U” shape. The solderable portion1410should extend from a location proximate (but not necessarily all the way to) an edge1412of the substrate400to another location proximate the same or another edge of the substrate400. Thus, the solderable portion1410should substantially bound the open portion of the channel1400between the solderable portion1410and the edge(s)1412of the substrate400, i.e., collectively, the solderable portion1410and the edge(s)1412form a boundary around the open portion of the channel1400. As can be see inFIG. 14, the solderable portion1410does not completely surround the channel1400.

As shown inFIG. 17, the circuit board1500may also include a solderable portion1700, shaped similar to the solderable portion1410on the bottom of the microphone package210. When the microphone package210is soldered to the circuit board1500, the solder1600(FIG. 16) takes the shape of the solderable portions1410and1700and, thus, forms the lower portion of a vertical wall of the acoustic path528. Conventional contact pads1414(FIG. 14) provide electrical and additional mechanical connections between the microphone package210and the circuit board1500.

Instead of solder, an adhesive, such as a conductive adhesive, may be used. In this case, the solderable portions1400and1700may be omitted, or they may be replaced by materials chosen for compatibility with the adhesive.

As shown inFIGS. 18,19,20and21, a circuit board1800may define a channel1804, and a bottom-ported microphone package may be mounted on the circuit board1800. If the microphone package is attached to the circuit board1800by solder, the bottom of the microphone package may include a solderable portion1410, as described above, with respect toFIG. 14.

Alternatively, as shown inFIGS. 22 and 23, a circuit board2200may include a notch2204(best seen inFIG. 23), rather than a channel1804. A notch may be easer to form than a channel. The open bottom of the notch2204may be sealed with an adhesive film or tape2208.

Another embodiment combines aspects of the microphone package described with reference toFIG. 15with aspects of the circuit board described with reference toFIG. 21orFIG. 23. That is, both the substrate400of the microphone package and the circuit board1800or2200may define channels and/or notches.

In yet another alternative embodiment, illustrated inFIG. 24, the top layer500of the substrate400defines an aperture2400, which functions as the input aperture to the microphone package. Although the aperture2400is not on the side2404of the substrate400, the aperture2400is closer to the side2404than an aperture defined in the side2408of the lid404would be. A suitable gasket should be used with the microphone package210illustrated inFIG. 24, as discussed with reference to the gasket220shown inFIGS. 1-3.

In another embodiment, illustrated inFIGS. 25 and 26, the substrate400defines a channel2500, which forms at least part of the acoustic path528. The comments regarding a gasket made in reference toFIG. 24also apply to this embodiment.

FIGS. 27 and 28illustrate a microphone package2700, according to yet another embodiment of the present invention.FIG. 27shows the microphone package2700in assembled and exploded views. The microphone package2700includes a top layer or lid2704and a wall layer2708. The wall layer2708may be made of one or more individual layers, as exemplified by dashed line2709. The microphone package2700also includes a channel layer2714that defines a hollow channel2716. The channel2716extends from an edge2718of the channel layer2714to a location away from the edge2718, such as to a location over which a microphone die (not shown) may be attached. The channel layer2714may be made of one or more individual layers, as exemplified by dashed line2720.

A bore layer2710defines a hole2720and is disposed intermediate the wall layer2708and the channel layer2714, such that when the channel layer2714and bore layer2710are assembled in registration with each other, the hole2720is in communication with the channel2716. When the wall layer2708and the bore layer2710are assembled in registration with each other, the hole2720is in communication with a volume defined by the wall layer2708.

The microphone package2700(or any other embodiment) may be provided as a kit of parts that includes the various layers2704,2708,2710and2714described above. The layers2704-2714may be made of plastic, ceramic or any other suitable material. The layers may be assembled using any suitable technique. For example, plastic layers may be assembled using an adhesive or welding by heat, ultrasonic energy or solvent, and ceramic layers may be assembled by brazing.

FIG. 29is a flowchart that describes producing a side-ported MEMS microphone package, according to one embodiment of the present invention. At2900, at least part of an acoustic path is defined through at least a part of a substrate to an aperture that is, or will be, under a lid, so the acoustic path is oriented other than perpendicular to the substrate surface to which the lid is, or will be, attached. As noted, the acoustic path may be defined in various ways, including laminating layers that each defines one or more holes, notches, channels, etc. For example, as indicated at2904, a first layer that defines the aperture may be laminated to a second layer that at least partially defines the acoustic path, such as by a notch, channel, etc. Optionally or alternatively, as indicated at2906, one or more holes may be bored at least partially through the substrate to define at least part of the acoustic path.

Optionally or alternatively, as indicated at2910, a second aperture may be defined in a substrate surface that is perpendicular to the surface to which the lid is, or will be, attached. The second aperture is in communication with the acoustic path.

Optionally or alternatively, as indicated at2914, a second aperture may be defined in the surface of the substrate. The second aperture is in communication with the acoustic path.

Optionally or alternatively, as indicated at2916, a second aperture may be defined in the surface of the substrate opposite the surface to which the lid is, or will be, mounted. The second aperture is in communication with the acoustic path.

Optionally, a solderable portion may be provided on the surface of the substrate opposite the surface to which the lid is, or will be, mounted, as indicated at2920. As noted at2924, the solderable portion may be in a U shape.

At2926, a MEMS microphone die is attached to the surface of the substrate. At2930, a lid is attached to the substrate surface to cover the microphone die and the aperture defined in the surface.

As noted, a circuit board may define a portion of the acoustic path.FIG. 30is a flowchart that describes producing a side-ported MEMS microphone assembly, according to another embodiment of the present invention. At3000, an aperture is defined in a surface of a circuit board adjacent a present or expected future location of the bottom port of a MEMS microphone package. At3004, an acoustic path is defined from a side of the circuit board, through at least a portion of the circuit board, to the aperture. The acoustic path may be defined in various ways, including laminating layers that each defines one or more holes, notches, channels, etc. For example, at3006, a first layer of the circuit board is laminated to a second layer of the circuit board. The first layer defines the aperture. The second layer defines at least a portion of a hollow channel in communication with the aperture. Optionally or alternatively, as indicated at3010, one or more holes may be bored at least partially through the circuit board to define at least part of the acoustic path.

Optionally, a solderable portion may be provided on the surface of the circuit board, as indicated at3014. The solderable portion is configured in an open shape, such as a U shape, and the solderable portion extends from a location proximate an edge of the circuit board to another location proximate the edge of the circuit board.

At3016, a bottom side of a bottom-ported MEMS microphone package is attached to the surface of the circuit board, so the bottom port of the microphone package is in communication with the aperture in the surface of the circuit board.

While the invention is described through the above-described exemplary embodiments, it will be understood by those of ordinary skill in the art that modifications to, and variations of, the illustrated embodiments may be made without departing from the inventive concepts disclosed herein. For example, although some aspects of producing side-ported microphone packages and assemblies have been described with reference to flowcharts, those skilled in the art should readily appreciate that functions, operations, decisions, etc. of all or a portion of each block, or a combination of blocks, of the flowchart may be combined, separated into separate operations or performed in other orders. In addition, although a microphone package has been described as being made from various materials, the disclosed methods and structures may be used with other materials. Furthermore, disclosed aspects, or portions of these aspects, may be combined in ways not listed above. Accordingly, the invention should not be viewed as being limited to the disclosed embodiment(s).