Damage of a connection between a connector and a circuit board on which the connector is mounted is to be prevented at the time of connecting the connector with a corresponding connector on a host side. The metal complexes of N-substituted thiourea are defined by the following formula wherein R1 can be H, alkyl, alkenyl, alkynyl, aryl or heterocyclic groups; R2 can be H, alkyl, alkenyl, alkynyl or aryl groups; n=1 to 4; X\u2212 is a pharmaceutically acceptable anion and M is a coinage metal. The workpiece surface is then ground with the super-finish grinding wheel to a target diameter under the control of a sizing device. With the arrangement of the elements and wires in the pixel portions, the integration can be increased and the resolution in the horizontal and vertical directions can be improved.