Advanced UV Laser Lithography Using a Tiltable Platform for 3D Microfabrication

This paper presents a computer-controlled tiltrotational UV-laser exposure system for 3D microfabrication. The system incorporates a beam expander to enlarge the beam width of a 405 nm laser diode, which serves as the light source. A computer-controlled sample holder platform utilizes two stepper motors to enable tilting and rotational movements, allowing the creation of complex microstructures using SU-8 photoresist via the lithography process. By implementing various combinations of tilting and rotation, arrays of intricate 3D microstructures, including pillars, angled pillars, horns, and bowties, were successfully fabricated, with feature heights ranging from 20 to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$500 \mu ~\mathrm{m}$</tex>. The tiltable UV-laser exposure system holds significant potential for applications in 3D microelectromechanical systems (MEMS), such as micro-biosensors and micro-antennas for biomedical and RF applications.