3D SU-8 structures assembled via micro-Lego

Abstract

Deterministic multi-layer micro-scale assembly of SU-8 polymer objects as well as the cohesively joined SU-8 interface strength have been investigated. The process of SU-8 photoresist (PR) into retrievable individual micro-scale objects format called 'ink' is reviewed and the construction of three-dimensional (3D) unique micro-structures via micro-Lego, which refers to the transfer printing of the ink onto a target site in conjunction with permanent joining has been demonstrated. Owing to the additive 3D manufacturing nature of the micro-Lego, the demonstrative micro-scale architectures are unattainable through other means of micro-manufacturing including photolithography. The mechanical integrity of the SU-8 and SU-8 interface formed by micro-Lego is inspected by probing SU-8 cantilever specimens using a nanoindenter and the results are examined by finite element analysis (FEA). The analysis reveals that the joining strength is ∼ 0.988 J/m