Methods of manufacture of bottom port multi-part surface mount MEMS microphones

A method for manufacturing a plurality of solder reflow surface mount microelectromechanical system (MEMS) microphones, the method comprising:

• providing an unsingulated panel comprised of a plurality of individual top portions, wherein each top portion has upper and lower surfaces and comprises at least one metal layer and at least one printed circuit board material layer, wherein the at least one metal layer comprises the lower surface of the top portion, and wherein the lower surface has a coupling area and an inner area, the coupling area being arranged between the inner area and the edges of the top portion, and completely surrounding the inner area;
• providing an unsingulated panel comprised of a plurality of individual spacer portions, wherein each spacer portion has upper and lower surfaces and comprises at least two metal layers with at least one printed circuit board material layer of predefined thickness disposed between the two metal layers, wherein one metal layer comprises the upper surface of the spacer portion and the other metal layer comprises the lower surface of the spacer portion, and wherein the spacer portion further comprises a window having walls covered with a metal layer, and the window walls extend through the printed circuit board material layer to the upper surface and the lower surface;
• providing an unsingulated panel comprised of a plurality of individual bottom portions, wherein each bottom portion comprises:
• a base layer that comprises at least one layer of printed circuit board material, wherein the base layer has a substantially flat upper surface and a substantially flat lower surface, the upper surface having an inner area and a coupling area, the coupling area located between the inner area and the edges of the base layer, and completely surrounding the inner area;
• a plurality of metal pads located on the upper surface of the base layer, wherein at least one pad of the plurality of metal pads is positioned in the coupling area of the upper surface of the base layer;
• a plurality of solder pads located on the lower surface of the base layer, the plurality of solder pads arranged to be within the edges of the base layer;
• one or more electrical connections passing through the base layer, wherein the connections electrically couple one or more of the plurality of metal pads on the upper surface of the base layer to one or more of the plurality of solder pads on the lower surface of the base layer, and wherein the at least one metal pad positioned in the coupling area of the upper surface of the base layer is electrically coupled to one or more of the plurality of solder pads;
• an acoustic port located in the inner area of the base layer and passing completely through the base layer, wherein one of the second plurality of solder pads is a solder pad ring that completely surrounds the acoustic port in the base layer;
• and
• at least one passive electrical element electrically coupled between one of the plurality of metal pads and one of the plurality of solder pads;
• physically coupling a MEMS microphone die on the top surface of the base layer of each individual bottom portion in the unsingulated panel of individual bottom portions, and electrically coupling each MEMS microphone die to at least one of the first plurality of metal pads on the top surface of the base layer of its respective bottom portion in the unsingulated panel of bottom portions, the MEMS microphone die being arranged directly over the acoustic port in its respective bottom portion;
• physically coupling the unsingulated panel of top portions, the unsingulated panel of spacer portions, and the unsingulated panel of bottom portions to each other in a predetermined order;
• wherein a conductive material physically couples the lower surface of each spacer portion to the coupling area of the upper surface of its respective bottom portion such that the window of each spacer portion and the inner area of the upper surface of each bottom portion are respectively aligned, and the metal layer on the window walls of each spacer portion is electrically coupled to the at least one metal pad positioned in the coupling area of its respective bottom portion;
• wherein a conductive material physically couples the upper surface of the spacer portion to the coupling area of the lower surface of its respective top portion such that the window of the spacer portion and the inner area of the lower surface of its respective top portion are aligned, and the metal layer of the top portion is electrically coupled to the metal layer on the window walls of its respective spacer portion;
• wherein electrical continuity is present between the metal layer in each top portion, its respective metal layer on the window walls of its respective spacer portion, and its respective at least one of the plurality of solder pads;
• and
• wherein the inner area of the upper surface of each bottom portion, the window walls of its respective spacer portion, and the inner area of the lower surface of its respective top portion, when the panels are coupled, define the internal acoustic chamber for each of their respective MEMS microphone die;
• singulating the coupled panels into a plurality of individual MEMS microphones, wherein each bottom portion, and its respective spacer portion and top portion cooperatively form a housing that has surfaces substantially perpendicular to the lower surface of the bottom portion and that protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage.

A method for manufacturing a plurality of solder reflow surface mount microelectromechanical system (MEMS) microphones, the method comprising:

• providing an unsingulated panel comprised of a plurality of individual base substrates, wherein each base substrate comprises:
• a core layer comprised of at least one layer of FR-4 printed circuit board material, wherein the core layer has a substantially flat top surface and a substantially flat bottom surface, the top surface having a die mount region and an attachment region, the attachment region positioned between the die mount region and the edges of the core layer, and completely surrounding the die mount region;
• a plurality of metal pads located on the top surface of the core layer, wherein at least one pad of the plurality of metal pads is located in the attachment region of the top surface of the core layer;
• a plurality of solder pads located on the bottom surface of the core layer, the plurality of solder pads arranged to be within the edges of the core layer;
• a plurality of electrical connections passing through the core layer that electrically couple one or more of the plurality of metal pads on the top surface of the core layer to one or more of the plurality of solder pads on the bottom surface of the core layer, and wherein the at least one metal pad located in the attachment region of the top surface of the core layer is electrically coupled to one or more of the plurality of solder pads;
• an acoustic port located in the interior region of the core layer and passing completely through the core layer, wherein one of the second plurality of solder pads is a solder pad ring that completely surrounds the acoustic port in the base substrate;
• and
• a pressure-equalizing MEMS microphone die having an internal acoustic channel mounted in the die mount region of the core layer, and electrically coupled to one or more of the metal pads on the top surface of the core layer, the internal acoustic channel of the MEMS microphone die being arranged directly over the acoustic port in the core layer of its respective base substrate;
• providing a plurality of enclosure elements, the plurality comprising:
• an unsingulated panel comprised of a plurality of individual first enclosure elements, wherein each first enclosure element has having substantially flat top and bottom surfaces and comprises at least two metal layers with multiple FR-4 printed circuit board material layers of predefined thickness disposed between the two metal layers, wherein one metal layer comprises the top surface of the first enclosure element and the other metal layer comprises the bottom surface of the first enclosure elements;
• an unsingulated panel comprised of a plurality of individual second enclosure elements, wherein each second enclosure element has substantially flat top and bottom surfaces and comprises at least one metal layer, a FR-4 printed circuit board material layer, wherein the metal layer comprises the bottom surface of the second enclosure element, and wherein the bottom surface has an attachment region and an inner region, the attachment region being arranged between the attachment region and the edges of the second enclosure element, and completely surrounding the attachment region;
• physically coupling the unsingulated panel of first enclosure elements and the unsingulated panel of second enclosure elements to each other to form an unsingulated panel of enclosures, wherein the top surface of each first enclosure element is physically coupled to the attachment region of the bottom surface of its respective second enclosure element with a conductive material;
• wherein each first enclosure element further comprises an interior open volume with walls, thereby exposing the inner region of the bottom surface of its respective second enclosure element;
• and
• wherein the interior open volume walls of each first enclosure element have a metal layer that is electrically connected to the bottom surface metal layer of its respective second enclosure element;
• joining the unsingulated panel of base substrates and the unsingulated panel of enclosures to form a housing that has an internal acoustic chamber for the MEMS microphone die, and that protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage, wherein the bottom surface metal layer of each first enclosure element is physically joined to the attachment region of its respective base substrate with a conductive material, and wherein the interior open volume of each first enclosure element is aligned with the die mount region of its respective base substrate, and the metal pad positioned in each attachment region is electrically coupled to the metal layer of the interior open volume walls in its respective first enclosure element;
• wherein the interior region of the bottom surface of each second enclosure element, the interior open volume walls of its respective first enclosure element, and the die mount region of its respective base substrate define the internal acoustic chamber for its respective MEMS microphone die;
• wherein electrical continuity exists between the metal layer of each second enclosure element, the metal-covered interior open volume walls of its respective enclosure element, and one or more of the plurality of solder pads on its respective base substrate;
• and
• singulating the coupled panels into a plurality of individual MEMS microphones, wherein, for each MEMS microphone, the length of the base substrate and the length of the enclosure are substantially equal, and the width of the base substrate and the width of the enclosure are substantially equal.

A method for manufacturing a plurality of solder reflow surface mount microelectromechanical system (MEMS) microphones, the method comprising:

• providing a plurality of pressure-equalizing MEMS microphone die, each MEMS microphone die having an internal acoustic channel;
• providing an unsingulated panel comprised of a plurality of individual first housing elements, wherein each first housing element has substantially flat top and bottom surfaces and comprises at least a metal layer and at least one printed circuit board material layer, wherein the metal layer comprises the bottom surface of the first housing element, wherein the bottom surface has an attachment region and an interior region, the attachment region located between the interior region and the edges of the first housing element and completely surrounding the interior region;
• providing an unsingulated panel comprised of a plurality of individual second housing elements, wherein each second housing element has substantially flat top and bottom surfaces and comprises at least first and second metal layers with at least one printed circuit board material layer of predefined thickness disposed between the first and second metal layers, wherein the first metal layer comprises the top surface of the second housing element and the second metal layer comprises the bottom surface of the second housing element, wherein the second housing element further comprises an aperture having metal-covered walls, and the aperture walls extend through the printed circuit board material layer to the top and bottom surfaces of the second housing element;
• providing an unsingulated panel comprised of a plurality of individual third housing elements, wherein each third housing element comprises:
• a core layer comprised of at least one layer of printed circuit board material, wherein the core layer has a substantially flat top surface and a substantially flat bottom surface, wherein the top surface has an interior region and an attachment region, the attachment region being arranged between the interior region and the edges of the core layer, and the attachment region completely surrounds the interior region;
• a plurality of metal pads disposed on the top surface of the core layer, wherein at least one pad of the plurality of metal pads is positioned in the attachment region of the top surface of the core layer;
• a plurality of solder pads disposed on the bottom surface of the core layer, the plurality of solder pads arranged to be within a perimeter of the bottom surface of the core layer;
• an acoustic port located in the interior region of the core layer and passing completely through the core layer, wherein the acoustic port is disposed in a position offset from the centerpoint of the third housing element, and wherein one of the second plurality of solder pads is a solder pad ring that completely surrounds the acoustic port in the core layer;
• and
• one or more electrical vias located inside the core layer, wherein the vias electrically couple one or more of the plurality of metal pads on the top surface of the core layer to one or more of the plurality of solder pads on the bottom surface of the core layer, and wherein a via electrically couples the at least one metal pad positioned in the attachment region of the top surface of the core layer to one or more of the plurality of solder pads;
• mounting one of the plurality of MEMS microphone die to the top surface of the core layer of each third housing element in the panel of unsingulated third housing elements, and electrically coupling the mounted MEMS microphone to the plurality of metal pads on the top surface of the core layer of its respective third housing element;
• attaching the unsingulated panel of first housing elements, the unsingulated panel of second housing elements, and the unsingulated panel of third housing elements to each other in a predetermined order;
• wherein a conductive material physically couples the attachment region of the bottom surface of each first housing element to the top surface of its respective second housing element to such that the interior region of the bottom surface of each first housing element and the aperture of its respective second housing element are aligned, and the metal layer of each first housing element is electrically coupled to the metal-covered aperture walls of its respective second housing element;
• wherein a conductive material physically couples the bottom surface of each second housing element to the attachment region of the top surface of its respective third housing element such that the aperture of each second housing element and the interior region of the top surface of its respective third housing element are aligned, and the metal-covered aperture walls of each second housing element are electrically coupled to the at least one metal pad positioned in the attachment region of the its respective housing element;
• wherein the interior region of the bottom surface of each first housing element, the aperture walls of its respective second housing element, and the interior region of the top surface of its respective third housing element, when the panels are attached, define the acoustic chamber that is a front volume for its respective MEMS microphone die, and acoustically couples its respective acoustic port to the MEMS microphone die;
• and
• wherein electrical continuity exists between the metal layer of each first housing element, the metal-covered aperture walls of its respective second housing element, and one or more of the plurality of solder pads on its respective third housing element;
• and
• singulating the coupled panels into a plurality of individual MEMS microphones, wherein the first housing element, and it respective second, and third housing elements cooperatively form a housing that has surfaces substantially perpendicular to the bottom surface of the third housing element, that has an internal acoustic chamber for the MEMS microphone die, and that protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage.