Process–Structure–Performance Correlation in Femtosecond Laser Stealth Dicing of Silicon Carbide

Stealth dicing (SD) with ultrafast lasers enables damage-free singulation of silicon carbide (SiC) wafers, yet most reported schemes rely on hybrid processes or aberration-corrected optics that hinder industrial uptake, and the quantitative link between processing parameters, internal modified structures, and cleavage performance remains poorly established. Here, the SD of 4H-SiC is investigated using a simple single-beam femtosecond laser system combined with a full factorial orthogonal design.

Focal position and laser power are identified as the dominant factors governing internal modification position and surface damage, whereas pulse duration and second-order interactions are statistically insignificant; a damage-free process window with focal positions of −80 to −120 µm is predicted and experimentally verified. Within this window, laser power mainly controls the size of the modified structure, while pulse duration determines whether modification is dominated by nonlinear ionization or by thermal accumulation, with a critical self-focusing power of 1.04 MW.