Using femtosecond laser to processing irregular-shaped holes in fine metal mask

Laser fabrication of holes in fine metal mask (FMM) has attracted significant research attention in recent years; however, the laser processing of irregularly shaped holes remains underexplored. To address this gap, we propose a femtosecond-laser processing method for fabricating irregularly shaped holes in FMM. The method enables the selection of required laser parameters, determination of the ablation contour for each layer, improvement of processing efficiency, and ultimately the fabrication of the target hole. Numerical simulations are conducted to evaluate the method's ability to control the hole Taper angle. We also built a laser processing system for machining irregular-shaped holes in FMM, and conduct experiments to validate the accuracy of the numerical model. Using optimized parameters, we fabricate an irregular-shaped hole with an elliptical upper opening, a rounded-rectangle lower opening, and a controlled Taper angle. This work provides an effective approach for femtosecond-laser fabrication of irregular-shaped holes in FMM.