Ultra-fine patterning technology by utilizing nano-silver catalysts in MSAP

This paper presents the investigations regarding the reactions of nano Ag catalysts and Pd catalysts on Cu foils. According to the survey, the nano Ag catalysts can be removed immediately and detached from the Cu foils in seed layer etching steps. But the Pd catalysts will deposit on the Cu foils again while etching because of the substitution from Cu to Pd; consequently the Pd catalyst steps will cause the deposition outside fine patterns in final treatments even in Modified Semi Additive Process (MSAP). With the electroless copper plating process using the nano Ag catalysts, it becomes possible to conduct the ultra-fine patterning of Line/Space (L/S) = 5 μm/5 μm.