Abstract: A method is proposed for use to break integrally-connected electrically-conductive traces on a circuited substrate used in TFBGA (Thin & Fine Ball Grid Array) semiconductor packaging technology, so as to make the electrically-conductive traces open-circuited for the implementation of open-circuited testing on the electrically-conductive traces on the substrate. The proposed method is characterized in the forming of a resistively-enlarged point at the terminal of each electrically-conductive trace on the substrate, which can be melted away while leaving each electrically-conductive trace intact simply by applying an electrical current of an adequate magnitude to pass through each electrically-conductive trace. As each electrically-conductive trace is open-circuited, an open-circuited testing procedure can be then performed on the electrically-conductive on the substrate.