Product Code: ICAL08_M506

Laser Micromachining of Microchannel Branching Networks into Silicon with a Femtosecond Fiber Laser
Authors:
DongHyuck Kam, University of Michigan; Ann Arbor MI USA
Lawrence Shah, Imra America, Inc.; Ann Arbor MI USA
Jyoti Mazumder, University of Michigan; Ann Arbor MI USA
Presented at ICALEO 2008

We describe rapid prototyping of a micro-channel branching network into silicon wafer with a femtosecond pulsed fiber laser. The branching network is designed as a blood oxygenator. This network bifurcates according to Murrays Law over 11 generations with depths ranging from 20µm to 200µm, and satisfies the necessity of equal path lengths. In development of such micro-fluidic structures, the mask-less laser direct writing will reduce time and cost compared with the conventional photolithography based technique. The flexibility of laser direct writing facilitates creating a multi-depth structure of the branching network. Femtosecond pulses provide the unique ability to fabricate micro-structures with minimized ablation debris and collateral damage to surrounding material. In combination with a galvanometric scanning system, overall fabrication speed is increased using a high repetition rate femtosecond laser. Influences of operating parameters, such as the pulse energy, the focal position, the transverse speed, and the number of passes, on the depth and the surface roughness of micro-channels are investigated. Based on the result, combinations of laser parameters are selected to realize designed branching networks.