US Patent 10291973 Sensor device with ingress protection

A microphone includes a base and a microelectromechanical system (MEMS) die and an integrated circuit (IC) disposed on the base. The microphone also includes a cover mounted on the base and covering the MEMS die and the IC. The cover includes an indented region or an inwardly drawn region that define a top port through which acoustic energy can enter the microphone and be incident on the MEMS die. The microphone also includes a filtering material disposed on the top port on an outside surface of the cover and within the indented region or the inwardly drawn region. The filtering material provides resistance to ingression of solid particles or liquids into the microphone.