Microfabrication of wide-measurement-range load sensor using quartz crystal resonator

We successfully established a wafer level fabrication process of the quartz crystal resonator (QCR) load sensor using atomic diffusion bonding. The proposed sensor has three-layer structures; two Si-hold layers and a quartz layer. Using microfabrication and atomic diffusion bonding, the assembly process was simplified. The fabrication process enables further miniaturization of the QCR sensor due to the simplified assembling method. The fabricated sensor is easily integrated in the outer package and can be designed the measurement range. Finally, we succeeded in multi-biosignals (heartbeat, body motion) detection using fabricated QCR sensor and the outer case.