Fabrication of 3D Microrobotic Parallel Actuator Architecture

ABSTRACT In this paper, we report on the micro/nanofabrication of a 2×1 microrobotic parallel actuator architecture for applications in biomanipulation and genetic therapy. The architecture has arrays of independently actuated micro-nano-needles with 3D mobility. This device is capable of precise micro-nano manipulation tasks, such as targeted drug delivery into single cells in vitro and aspiration critical for biomanipulation on a parallel high throughput scale. The four-sided single-unit actuator ( 4SA ) microrobot has been jointly fabricated at the University of Canterbury’s ( UC ) Nanofabrication Facility and the Canadian Microelectronics Corporation ( CMC ). The three-sided single-unit actuator ( 3SA ) microrobot is being fabricated by CMC in collaboration with Micralyne Inc. The 4SA microrobot is fabricated using a combination of silicon-on-insulator multi-user MEMS process ( SOIMUMPs ) and bonding with another silicon wafer containing a long-standing tower for parallel-plate actuation. It involves a combination of photolithography, dry etching ( RIE ), oxidation, KOH wet etching, bonding and the micro-nanoneedle tip being fabricated using focused ion beam technology. The 3SA microrobot is fabricated using MicraGEM-Si technology, developed by Micralyne Inc. in Canada. This process uses two SOI wafers with the bottom electrode being etched on the base wafer and the suspended actuator structures on the top device wafer. The two wafers are electrically connected through the bond interface, resulting in 3D routing of electrical signals. We report details of the singular and parallel architecture fabrication, working principle in brief, significant results from the SiO 2 etch study of the formation of Si nanopillars and briefly discuss the experimental results from the characterization of the 4SA microrobot.