Laser stealth dicing of β-Ga2O3: Theoretical and experimental studies

Abstract

Gallium oxide (Ga₂O₃) is an ultra-wide bandgap semiconductor with excellent potential for high-power and ultraviolet optoelectronic device applications. High-performance Ga₂O₃-based high-power devices rely heavily on precise processing, especially in wafer dicing. Laser stealth dicing (LSD) is an innovative laser technology that utilizes a focused laser to create subsurface modifications in the wafer without surface damage. LSD has broad application prospects in the field of semiconductor precision processing. In this work, the idea of achieving high-quality dicing of β-Ga₂O₃ wafers via LSD was proposed. A combination of atomistic simulations and experiments was used to understand the underlying mechanism of LSD of β-Ga₂O₃ wafers. On the one hand, the laser loading and fracture process of β-Ga₂O₃ wafers were simulated using molecular dynamics (MD) methods as well as a machine learning potential. The effects of single-pulse energy on LSD were analyzed through the lattice residual pressure, the final total energy of the system, the internal atomic strain, and the maximum stress value during uniaxial tension. On the other hand, based on the MD simulations, LSD was successfully performed on β-Ga₂O₃ wafers along three main crystal planes in the laboratory, resulting in good surface quality. This work not only provides profound optimization strategies for the LSD process of β-Ga₂O₃, establishing the foundation for high-quality dicing of β-Ga₂O₃ wafers, but also verifies the accuracy of MD simulations in predicting trends related to the LSD, offering a potential approach for high-quality dicing of other materials in future research.