A Full 3D Printing Method for Monolithic Integration of an Accelerometer and a Force Sensor

This paper presents monolithic integration of an accelerometer and a force sensor based on a rapid 3D printing fabrication approach. With a triple-extruder 3D printer, for the first time, an insulating material, a conductive material, and a sacrificial material were printed alternately to fabricate a multifunctional MEMS device in a one-step printing process within an hour and without any additional metallization and assembly processes. Moreover, with the advantage of 3D printing in building geometrically complex structures, the accelerometer and the force sensor were easily integrated in vertical stacking using vertical feedthroughs in a TSV (Through-Silicon Via)-like design so that the multifunctional device could be directly mounted on a PCB substrate as a chip scale package. The performances of the multifunctional device indicate that the 3D printed sensors can be used in real-time motion and force monitoring for personalized customization and the monolithic integration method has potential applications in producing various integrated MEMS sensors.