Post-CMOS on-chip integration of 3D MEMS inductors using a novel chip embedding technique

This letter reports the integration of high-Q vertical ring inductors on individual small CMOS chips using a novel chip embedding technique. A small CMOS voltage controlled oscillator (VCO) chip which has 2×2mm² in size and 5.8 GHz of operating frequency was used for post integration. The chip embedding technique enables the post-CMOS processing on such a tiny individual chip. The integration of vertical ring inductor on the CMOS chip was completed by Plastic Deformation Magnetic Assembly (PDMA). Both numerical simulation and experimental characterization of the inductor performance have been conducted. The vertical ring inductor manifests a stable inductance value over a wide frequency range (45MHz~8 GHz) and a high quality factor of 110 at the operation frequency of the VCO (5.8 GHz).