Ultra-thin borosilicate glasses, such as the 50 µm thick Schott D263, are crucial substrates for next-generation flexible electronics, micro-optics, and medical sensors. However, standard separation processes often induce detrimental micro-cracks and residual stresses, compromising the mechanical integrity of the final component. Consequently, achieving defect-free edges currently necessitates complex and time-consuming two-step procedures, such as Laser-Induced Deep Etching, to restore the substrate's mechanical strength.

This study investigates the processing quality of ultra-thin glass using an ultrashort pulse laser system (λ = 1030 nm) equipped with a 20 mm biconvex focusing optic. To identify the optimal ablation regime and minimize thermal damage, a multi-pass cutting strategy utilizing 36 passes is systematically evaluated across three distinct pulse durations: 1 ps, 395 fs, and a sub-100 fs regime (down to 58 fs in this study) achieved through external pulse compression of the Pharos laser with the MIKS1_S compressor (n2-Photonics). Surface topography and edge quality are rigorously evaluated using a 3D laser scanning microscope to capture the exact extent of defect formation.

Experimental results demonstrate a significant dependency of the edge quality on the selected pulse duration. The findings clearly indicate that shorter pulse durations directly correlate with a substantial reduction in chipping along the cut edge. Operating in the shortest pulse duration regime of 58 fs shifts the dominant absorption mechanism towards deterministic multi-photon ionization. This effectively suppresses stochastic avalanche processes and minimizes thermo-mechanical shockwaves, providing essential insights for the defect-free processing of ultra-thin glasses and ensuring high mechanical resilience for industrial scale-up.