Die size reduction by optimizing the dimensions of the vertical feedthrough pitch and sealing area in the advanced MEMS (aMEMS) process

This paper presents the recent reduction of the die size by 44% in the Advanced MEMS (aMEMS) process, now being compatible in size with most of the available through-wafer packaging processes while offering the unique simplicity of the aMEMS process. Size reduction is achieved by reducing the pitch of vertical feedthroughs from 700 μm down to 350 μm and the bonding area width from 300 μm down to 100 μm, approaching to the process limits and still preserving the hermeticity of the package. Both small and large dies, containing the identical resonance sensors inside for benchmarking, are produced together on the same wafer. The cavity pressures of the both dies are measured to be around 1 mTorr even after thermal cycling tests.