Product Code: ICA11_M905

Laser Micromachining of Metal Films on Polymer Membranes
Authors:
Tim Gerke, Fianium Inc.; Eugene OR USA
Dylan Fast, Microtech Instruments; Eugene OR USA
Vladimir Kozlov, Microtech Instruments; Eugene OR USA
Presented at ICALEO 2011

This work demonstrates that ultrafast picosecond lasers provide the gentle touch and cold ablation required to remove metal films from ultra-thin polymer membranes without damaging the membrane substrate. Metal films of 10-100 nm in thickness are selectively removed from free-standing polymer membranes of thickness of 3 um. The metal is completely removed in a lift-off process, enabled by a single laser pulse (10-40 ps, 532 nm). No damage to the polymer membrane is observed even for samples with the metal completely removed over 50x50 mm area of the membrane, despite residual linear and possibly non-linear absorption of the laser power in polymer substrate. As an application example the metal films are patterned into wire-grids with periods from 15 to 80 um and 50% duty cycle to create polarizers for the terahertz spectrum. The terahertz polarizers function well and can be fabricated with extremely high throughput relative to conventional methods. The direct laser write processing technique allows for arbitrary patterns and feature sizes can be easily realized. This method can be extended to cold ablation processing of multilayer films fabricated on thin polymer substrates for applications such as plastic electronics, displays and solar cells.