A MEMS audio device includes a first wafer having a top with a first cavity and a bottom with a vent hole coupled to the first cavity, wherein the bottom having first contacts, a second wafer disposed upon the first wafer having a flexible material layer disposed above the first cavity, a third wafer disposed upon the second wafer having physical contacts coupled to the second wafer, wherein the third wafer includes a second cavity disposed above the flexible material layer, a wiring wafer disposed below the first wafer having a second vent hole coupled to the first cavity, wherein the wiring wafer having second contacts coupled to the first contacts, and wherein the flexible material layer forms a diaphragm for the MEMS audio device.

An electronic device includes a substrate having a first surface and a second surface opposite to each other in a thickness direction of the substrate, wherein the substrate has first and second connection vias which penetrate through the substrate in the thickness direction of the substrate, and first and second conductive pillars are respectively in the first connection via and the second connection via; a switch on the first surface of the substrate and comprising first and second signal electrodes, wherein the first signal electrode is electrically coupled to a first terminal of the first conductive pillar, and the second signal electrode is electrically coupled to a first terminal of the second conductive pillar; and a filter on the second surface of the substrate.

A MEMS audio device includes a first wafer having a top with a first cavity and a bottom with a vent hole coupled to the first cavity, wherein the bottom having first contacts, a second wafer disposed upon the first wafer having a flexible material layer disposed above the first cavity, a third wafer disposed upon the second wafer having physical contacts coupled to the second wafer, wherein the third wafer includes a second cavity disposed above the flexible material layer, a wiring wafer disposed below the first wafer having a second vent hole coupled to the first cavity, wherein the wiring wafer having second contacts coupled to the first contacts, and wherein the flexible material layer forms a diaphragm for the MEMS audio device.