This work investigates a post-CMOS (complementary metal-oxide semiconductor) bulk micromachining process for fabricating suspended microstructures. The advantage of the post-CMOS process is easy execution with low-cost maskless wet etching. The post-CMOS process involves wet etching to remove sacrificial layers, which are stacked layers formed from metal and via layers, to expose the silicon substrate. Then, KOH solution is employed to etch the silicon substrate to develop deep cavities and generate suspended structures. Many suspended structures, which include bridges and plates, are fabricated using the post-CMOS bulk micromachining process. With the same process, two devices that are a suspended micro inductor and a micro hot plate are manufactured successfully. Experimental results reveal that the maximum quality factor of the suspended micro inductor is 4.8 at 4 GHz, and the micro hot plate can generate a high temperature of 300 °C with an applied voltage of 4 V, which has excellent thermal isolation and heating effect.

Packaging is a core technology for the advancement of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). We discuss MEMS packaging challenges in the context of functional interfaces, reliability, modeling and integration. These challenges are application-dependent; therefore, two case studies on accelerometers and BioMEMS are presented for an in-depth illustration. Presently, most NEMS are in the exploratory stage and hence a unique path to identify the relevant packaging issues for these devices has not been determined. We do, however, expect the self-assembly of nano-devices to play a key role in NEMS packaging. We demonstrate this point in two case studies, one on a silicon nanowire biosensor, and the other on self-assembly in molecular biology. MEMS/NEMS have the potential to have a tremendous impact on various sectors such as automotive, aerospace, heavy duty applications, and health care. Packaging engineers have an opportunity to make this impact a reality by developing low-cost, high-performance and high-reliability packaging solutions.

No abstract

No abstract