Pads disposed on a printed circuit board and exposed to the outside of the printed circuit board are surface-treated with an electrolytic plating (or an electrolytic Au plating) to improve reliability of the pads, to prevent the pads from oxidizing, or to perform a wire bonding on the pads.
For the electrolytic plating, an electroplating line (hereinafter, referred to as a “plating line”) is required to be designed when designing the printed circuit board.
The plating line is removed by a process such as an etching process after the electrolytic plating is completed. However, a portion of the plating line remains and causes a signal interference or an electromagnetic interference.