Metal mask, also known as metal reticle, is an ideal shading plate for making mask patterns. The metal mask uses photo-etching technology to realize the exposure process by shading and transmitting light, and the information of these patterns will be transmitted to the semiconductor chip. Masks are widely used, and masks are required in fields involving lithography, such as IC (Integrated Circuit), FPD (Flat Panel Display), PCB (Printed Circuit Boards), MEMS (Micro Electro Mechanical Systems), SCSP (Stacked Chip Scale Package) ect.