Direct Manufacturing of Functional Structures on 3D microscale surfaces by Laser Dynamic Forming

G. Huang, G.J. Cheng
Purdue University, US

Keywords: direct manufacturing, functional materials, 3D microscale surfaces, laser dynamic forming

Summary:

This paper demonstrates a scalable and fast-shaping top-down integration technique, Laser Dynamic Forming (LDF), capable of manufacturing 3D functional structures conformal to micro-to-mesoscale curvilinear features on various substrates by the laser-induced shockwave. The functional devices in this study, temperature sensors, preserved their electrical resistance and temperature coefficient of resistance (TCR) after selectively laser forming on metallic interconnections. The ductile interconnections inherit 3D microscale structures on various substrates and experience significant plastic deformations without excessive necking and fracture. It was realized by the polymeric encapsulation of functional materials and the shockwave controlled by laser pulse intensity. It was revealed in experiments and analytical solutions that the encapsulation layer (parylene-C) absorbs most of shockwave energy by large thickness reduction and extends the formability of ductile interconnections by high-quality deposition and bonding. Comparatively, the thickness of ductile functional materials was reduced very limitedly and uniformly along the 3D microfeatures by low and moderate laser intensities. The manufacturability of functional structures is determined by the applied laser intensity, as well as the size and aspect ratio of 3D microfeatures.