Electroplating multi-trace circuit board substrates using single tie bar

A method of electroplating circuit board substrate having a high density, multi-trace circuit pattern formed on at least one major surface of an insulative substrate, without requiring formation and at least partial removal of a large plurality of electrically conductive tie bars contacting each of the circuit traces for supplying electroplating potential/current, comprises providing the at least one major surface with a single tie bar having at least a pair of laterally extending arms in simultaneous electrical contact with an end of each trace. Portions of the tie bar extension arms are selectively removed after completion of electroplating, e.g., by laser drilling or plasma etching, to electrically separate each of the circuit traces from the tie bar. According to an embodiment of the invention, electroplating is simultaneously performed on a dual-sided substrate including electrically interconnected circuit patterns formed on opposite sides thereof. The invention enjoys particular utility in the fabrication of ball grid array (BGA) semiconductor device packages.