Novel laser drilling strategy based on dynamic modulation and backside chemical jet assistance

To achieve high-quality microhole processing at elevated laser powers, this work proposes a synergistic strategy—backside flowing chemical-assisted laser pulse-delayed scanning drilling [time-delayed (TD)-backside chemical-assisted laser drilling (BCALD)]. Unlike conventional immersion-based liquid-assisted laser drilling, which often suffers from significant plasma shielding and uncontrollable chemical etching, TD-BCALD significantly enhances energy utilization efficiency by precisely modulating the spatiotemporal coupling between laser pulses and chemical reactions. By coordinating a continuous flow of environmentally benign chemical fluid with an intermittently activated high-power laser in a pulse-delay regime, this approach enables highly controllable synergistic interactions within the laser-induced high-temperature zone. We first outline the individual mechanisms and key parameters of BCALD and laser pulse-delayed scanning drilling and then highlight how pulse-delay timing critically modulates their synergy. Detailed scanning electron microscopy and x-ray energy spectrometry analyses further elucidate the underlying mechanism of heat accumulation decoupling. Under an optimal 100 ms pulse delay, TD-BCALD achieves a taper angle of 0.987°, roundness of 98.9%, and surface roughness of 1.502 μm. These results, combined with the reduced chemical consumption and improved process stability, demonstrate the superior engineering potential and environmental benefits of TD-BCALD for advanced high-power laser microfabrication.