Rapid prototyping of microchannels into silicon with a femtosecond fiber laser

We report on rapid prototyping of microchannels onto silicon wafer with a femtosecond laser. The microchannel is a basic component composing microfludic structures for biomedical applications. In development of micro-fluidic structures, the maskless laser direct writing will reduce time and cost as a tool for rapid prototyping compared with the conventional photolithography based technique. While the ability of femtosecond pulses for micromachining has been proven in many applications, its slow processing speed is a challenge in practical applications. Utilizing the benefit of a high repetition of the fs laser, a wide machining range of channel depth is achieved with a reasonable processing speed. Influences of the number of scan passes and the scan speed on the material removal rate and the machining range are investigated to maximize the processing speed with the pulse energy of 10 µJ. As a demonstration, a multi-depth microchannel network is laser machined onto silicon.