Femtosecond Laser Etching for Microelectronic Chip Fabrication: Mechanisms, Applications, and Process Integration

Femtosecond laser etching has emerged as a powerful technique for high‐precision microelectronic chip fabrication, offering ultrafast processing speeds, minimal thermal effects, and exceptional spatial resolution. This paper systematically reviews key etching mechanisms, including laser‐induced backside wet/dry etching and hybrid additive‐subtractive approaches, and their dependence on laser–material interaction parameters. Representative applications in silicon micromachining, conductive path formation, microstructure fabrication, and advanced packaging are discussed. Technological developments in laser sources, beam shaping, motion control, and in situ process monitoring are also examined in the context of precision and scalability. Critical challenges such as surface roughness, thermal accumulation, and material selectivity are addressed through recent advances in ultrafast pulse engineering, process optimization, and intelligent feedback systems. Finally, this review outlines prospects for femtosecond laser etching in heterogeneous integration, MEMS, and quantum photonic systems, highlighting its pivotal role in next‐generation semiconductor manufacturing.