Micro structuring of photoresist with femtosecond laser pulses

Femtosecond laser pulses permit laser ablation almost free of any heat load to the material, which allows the structuring of various materials with high resolution and good edge definition. We present recent results on selective laser ablation of thick photoresists (AZ-Types) from dielectric substrates as a critical process step in MEMS (micro electromechanical systems) fabrication, capitalizing on the different ablation thresholds of the resist layer and the substrate material. The laser used was an ultrafast pulsed Yb:glass regenerative amplifier with a pulse duration of 300 fs.