Precision ultrafast laser micromachining of silicon microfluidic channels

Abstract This study investigates the micromachining of microchannels on silicon surfaces using a femtosecond pulsed laser with an 800 nm wavelength and 100 fs pulse duration. The process parameters were modeled and optimized using the Response Surface Methodology based on the Box-Behnken design to enhance machining precision and efficiency. The effects of laser power, scanning speed, and line spacing on depth, surface roughness, and material removal rate were systematically evaluated. Results showed that higher laser power (up to 750 mW) significantly increased MRR, whereas lower power (e.g., 50 mW) reduced material removal. Scanning speed inversely affected machined depth, while line spacing (5–15 μm) strongly influenced machining outcomes through parameter interactions. The highest material removal rate of 1.18 × 10 6 μm 3 s −1 was achieved under optimized conditions. Validation experiments confirmed the accuracy of the response surface methodology model, with optimized parameters (310 mW laser power, 10 mm s −1 scanning speed, and 5 μm line spacing) yielding a machined depth of 10 μm and surface roughness of 0.4 μm. Precise and thermally damage-free microchannels were successfully fabricated, demonstrating the effectiveness of this methodology for advanced silicon micromachining applications.