US Patent 9995641 Force sensor with gap-controlled over-force protection

Apparatus and associated methods relate to a force sensor having flip-chip mounted force-sensing die having a force-sensing element fabricated on an unflipped top surface and an unflipped back surface being thinned so as to create a flexible diaphragm responsive to an externally applied force, wherein, when the force-sensing die is flipped and mounted, a predetermined space remains between the top surface of the force-sensing die and the mounting substrate it faces, the substrate presenting a deflection limitation for the deformation of the flexible membrane during a force event. In an illustrative embodiment, the force sensor may have a mechanical stop to precisely establish a predetermined deflection limitation. In some embodiments, the predetermined deflection limitation may advantageously limit the deflection of the flexible membrane so as not to deflect beyond a breaking point.