Current Research Topics

Heterogeneous integration refers to the integration of separately manufactured components into a higher level assembly that provides enhanced functionality and improved operating characteristics. [Heterogeneous Integration Roadmap] Our group specializes in micro-transfer-printing and direct pattern transfer that advance high-end semiconductor device and display technologies such as 2.5/3D integrated circuits (ICs) and micro-LED/QD (quantum dot) LED displays through the heterogeneous integration.

Our group proposes a new micromanufacturing strategy which is inspired by LEGO or traditional masonry, complementary to conventional micromanufacturing approaches. This LEGO-like microassembly strategy is the full or partial fabrication of micro/nanosystems from individual micro/nanoscale materials deterministically manipulated via polymeric stamps and mechanically, electrically, thermally, and/or optically joined together. We are developing the tools, processes, and applications of the LEGO-like microassembly.

Using highly deformable soft materials in microrobots performing tasks at small scales could help fill the gap between high performance specialized functions of conventional micromachines and high tolerance versatility of biological organisms. Our group pursues a soft microrobot platform which leverages both soft organic parts for efficient shape control and microfabricated device-grade inorganic parts for superior surface functions simultaneously, which is highly desired but difficult to achieve with existing microrobot platforms.

Smart materials such as shape memory polymers (SMPs) show untapped potential when combined with biomimetic design processes to develop synthetic surfaces with various functionalities including adhesion, wetting, and optical functions. Our group has been exploring bioinspired design of micro/nanosturctured SMP and other composite surfaces exhibiting reversible dry adhesion and tunable wetting, provided by switchable structural and material properties.

Micro/nanoelectromechanical systems (M/NEMS) is the technology allowing the manufacture of very small devices and has mostly relied on monolithic microfabrication that originated from integrated circuit (IC) fabrication techniques. In microfabrication, a final structure is often built with repeatedly deposited layers which are patterned via electrochemical processes afterwards. Because of the repetitive layer-by-layer nature of the microfabrication, most M/NEMS devices are often limited to two-dimensional format. We employ our LEGO-like microassembly technology enabling unusual M/NEMS devices that exhibit new functionalities and/or architectures.