Abstract: A microelectromechanical circuit includes a cover attached to a package substrate by a thermoplastic. A MEMS device is disposed between the cover and the packaging substrate. The thermoplastic is substantially free of solvents. In addition, surfaces of the device are substantially free of solvents. The cover, the packaging substrate, and the thermoplastic form a protective enclosure around the device. The MEMS device may be formed on a substrate. The substrate may be attached to the packaging substrate by a thermoplastic. The thermoplastic may also be substantially solvent-free. A method for forming the circuit includes heating a thermoplastic to a temperature sufficient to remove all solvent from the thermoplastic. The temperature may be above a boiling point of the solvent. The method also includes arranging the thermoplastic between the cover and the packaging substrate and applying pressure and heat to the thermoplastic to form a protective enclosure around the device.

Abstract: A microelectromechanical circuit includes a packaging substrate having conductive features on its lower surface. The circuit may further include a microelectromechanical device formed upon the upper surface of the substrate, wherein an underside of at least one element of the device is in contact with the upper surface of the substrate. In some embodiments, the circuit may include one or more covers spaced above the substrate and the device. The circuit may further include a sealing structure laterally surrounding the device and interposed between the substrate and the covers. An array of microelectromechanical circuits may include a packaging substrate with first and second microelectromechanical devices laterally spaced upon its upper surface, first and second covers above the substrate and the first and second devices, and a sealing structure between the substrate and the first and second covers.