Characterization of laser-diced Si and SiC power device recast layers using advanced SEM techniques

The exponential growth of the electronics industry has been fueled by advancements in semiconductor technologies, with ultrathin dies and miniaturized components playing a central role in enhancing device efficiency and performance. However, these innovations present significant challenges for conventional fabrication methods, particularly in wafer singulation. Laser dicing has emerged as a promising alternative to traditional blade dicing, offering advantages such as cleaner cuts and compatibility with ultrathin wafers. Despite these benefits, laser dicing introduces challenges such as the formation of recast layers and heat-affected zones (HAZ), which can compromise the mechanical strength of semiconductor dies due to residual stresses and defects. This thesis investigates the microstructure, morphology, and residual stress fields of recast layers and HAZs in laser-diced silicon (Si) and silicon carbide (SiC) power devices. A combination of advanced techniques, including Scanning Electron Microscopy (SEM), High-Resolution Electron Backscatter Diffraction (HR-EBSD), and Electron Channeling Contrast Imaging (ECCI), is employed to characterize these features. The objective is to develop a rapid and cost-effective methodology for analyzing laser-induced damage and to establish correlations between laser parameters, material properties, and die strength, with the long-term goal of supporting quality control processes in industrial production.