Other materials processing

Ceramic is hard and brittle: mechanical processing presses on it with large forces and can crack the substrate. Femtosecond laser pulses form grooves without mechanical contact. Grooves 30, 50 and 70 µm deep were scribed at speeds up to 44.1 mm/s, and the 343 nm wavelength reduced the heat-affected zone from 8.23 µm to 4.88 µm.

Femtosecond lasers mill ceramics precisely but slowly. GHz bursts raise the throughput: trains of pulses at GHz intra-burst repetition rates split one high-energy pulse into many smaller ones. With 92 pulses per burst, alumina milling throughput rose from 6.39 mm³/min in single-pulse mode to 10.38 mm³/min.

Milling GaAs in ambient air leaves a band of debris redeposited along the trench walls. Under a layer of water the same process cuts deeper and cleaner: trench depth rose from 58 µm to 105 µm and the redeposition band shrank from 34 µm to 7.6 µm. Ablation efficiency was higher in all three regimes tested.

Mechanical dicing follows silicon’s crystallographic cleave planes, so diced chips come out with straight edges only. Femtosecond pulses cut FZ-Si wafers along curved contours instead: a 0.4 mm float-zone wafer was cut with a low heat-affected zone and an undamaged bottom surface.

SSAIL writes copper circuits directly onto dielectric surfaces: an ultra-short pulse laser draws the pattern, chemical activation follows it, and electroless plating deposits metal only on the lasered areas. Developed by FTMC and Akoneer, the process reaches trace widths down to 1 µm on PC/ABS, PMMA, PET, FR-4, Al₂O₃ ceramic, fused silica and silicon.

Heat-sensitive organic materials warp and char when a cutting process leaves heat behind. Femtosecond pulses remove material before heat spreads into the lattice: thin organic sheets for medical applications were cut at 100 mm/s with 350 fs pulses, with kerf widths down to 14.38 µm and no charring on the cut edges.