Microelectromechanical system having movable element integrated into leadframe-based package

A MEMS device (100) has an integrated circuit chip (101) and package comprising a leadframe-based plastic molded body (120) with an opening (122) through the thickness (121) of the body. A movable foil part (130) may be anchored in the body (120) and extend at least partially across the opening (122). The chip (101) may be flip-assembled to the leads (110) to span across the foil, and may be separated from the foil (130) by a gap. The leads may be on a leadframe of a prefabricated piece part, or may be fabricated in a process flow with metal deposition on a sacrificial carrier and patterning of the metal layer. The resulting leadframe may be flat or may have an offset structure useful for stacked package-on-package devices.