A review of laser ablation and dicing of Si wafers.

Over the last decade, lasers have been gradually employed for Si wafer dicing to replace blade dicing. Laser dicing has the potential to replace blade dicing as the future generation ultrathin wafer singulation method as it enables higher cutting speed, lower damage, and smaller kerf width but various technical challenges still remain to be resolved. In this article, laser ablation and dicing of Si wafers are reviewed in terms of the physics of laser-material interaction based on nanosecond, picosecond, and femtosecond pulse durations. The effects of various laser settings, dicing process parameters, and material factors on ablation rate, ablation precision and quality, and die fracture strength are discussed in detail. With the increasing usage of Cu stabilization layer on the backside of ultrathin Si wafers, we also review laser-material interaction in Cu and elaborate on recent findings on the effects of laser dicing through Si and Cu simultaneously on the microstructural and fracture strength properties of the die. Various approaches to improve the ablation rate, ablation quality, and die fracture strength are discussed. • Laser dicing of thin Si wafers is gaining more importance in the semiconductor industry because of its cost-effectiveness compared to conventional blade dicing. • Understanding laser ablation mechanisms remains a huge challenge because of the complexity of the processes taking place, the variety of species involved, and the range of length and time scales covered. • Many challenges remain for laser dicing of Si wafers primarily in three critical areas, i.e., ablation rate, ablation precision and quality, and die fracture strength. • Optimization of the ablation rate, ablation quality, and die fracture strength will require thorough consideration of all the influencing laser and process parameters in order to meet the requirements of the end product applications. [ABSTRACT FROM AUTHOR]