*********************************
There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
*********************************
Title: All-soft and 3D-integrated Multifunctional Microsystems Enabled by Liquid Metal and Soft Lithography
Committee:
Dr. Brand, Advisor
Dr. Ghovanloo, Chair
Dr. Inan
Abstract:
The objective of the proposed research is to explore all-soft and 3D-integrated multifunctional microsystems enabled by gallium-based liquid metal (eutectic gallium-indium alloy, EGaIn) and soft lithography. Lightweight, flexible, and stretchable wearable electronics have gained significant attention for various sensing applications ranging from entertainment to healthcare, but the mechanical mismatch between soft biological skins and conventional rigid and bulky electronic materials often limits the ultimate usability and leads to hard-soft material interface failure. To circumvent this limitation, the use of conducting liquid, such as EGaIn, has great potential because of its non-toxicity, low melting temperature, and excellent electrical and mechanical properties. However, EGaIn patterning challenges, particularly regarding minimum feature sizes, size-scalability, uniformity, and residue-free surfaces, have limited the demonstration of high-density, soft microelectronic devices. This research investigates an advanced EGaIn thin-film patterning based on soft lithography and a compatible vertical integration technique, which enable size-scalable and high-density EGaIn-based soft microelectronics. The proposed patterning technique overcomes the current limitation in EGaIn fabrication by demonstrating uniform and residue-free EGaIn thin lines with width from single micrometers to several millimeters at room temperature and under ambient pressure. Also, vertical integration using EGaIn-filled soft vias facilitates high-density integration as well as system-level flexibility and stretchability. By combining the scalable fabrication process and vertical integration approach, two types of all-soft and 3D-integrated microsystems are demonstrated: i) a finger-mountable strain sensing microsystem with reduced temperature sensitivity and ii) wireless and battery-free chemical microsystems for liquid- and gas-phase volatile organic compound (VOC) sensing.
