<p>Facing the requirements of wafer scribing, this paper proposes a megasonic-assisted laser processing method to address the issues of ablation products and low depth-to-width ratio in laser scribing. Through theoretical analysis of laser ablation and megasonic vibration, it is shown that megasonic waves can remove the liquid-phase material and molten debris generated during ablation from the processing area, thereby reducing the accumulation of ablation products and improving the depth-to-width ratio. Subsequently, a three-factor two-response experiment was designed using the response surface methodology. Experimental results demonstrate that the introduction of megasonic waves significantly improves the surface morphology of the wafer. After grooving, the area of ablation products on the wafer surface is reduced by 80 μm², representing a decrease of approximately 25%. The depth-to-width ratio of the ablated grooves is increased from 2.65 to 3.82 while the width remains largely unchanged, leading to enhanced processing efficiency. Moreover, a grid structure with favorable surface morphology was achieved using this method. This approach effectively improves the surface quality of wafer scribing, reduces ablation debris, and enhances the capability for deep processing in wafer scribing applications.</p>