Design, Fabrication, and Assembly of Multi-chip Walking Silicon Microrobots

Microrobots can someday be used as a tool to further expand investigative capabilities-- for example, archeologists could use them to research buried cities such as the one in Tiwanaku, Bolivia, or emergency response workers could send robots ahead in search-and-rescue operations. The anatomy of a microrobot can be broken down into its body, brain and power. Typically, each subsystem is fabricated using a different process, creating the need for multi-chip assembly. Microrobots in the literature are often assembled post-process using methods such as wire bonding, silver epoxy, and flip-chip bonding. These approaches tend to be time consuming, tedious and may even harm the devices. Additionally, not all of them provide the necessary mechanical robustness needed for a moving walking microrobot. This work presents a zero-insertion force (ZIF) socket as a solution to achieving robust electrical, and mechanical assembly of a walking silicon microrobot. The ZIF socket and body of the microrobot are composed of various micro-electro mechanical systems (MEMS) fabricated using a three-mask silicon-on-insulator (SOI) process. First, successful MEMS-MEMS assembly using a ZIF socket is presented, as well as important design considerations. Subsequently, proof-of-concept and first results for MEMS-CMOS assembly is shown, integrating a complimentary metal-oxide semiconductor (CMOS) chip into a ZIF socket. Finally, the full system design of a walking silicon microrobot (not yet fabricated) using the Single Chip micro Mote (SCµM) CMOS chip as a brain, and a solar cell chip (Zappy2) for power is introduced