Evaluation System for Ionic Migration On/In the Superconnect Leveled Printed Circuit Board by Means of AC Impedance Method
Micro-fabricated Printed Circuit Boards (PCB) using environmental friendly materials and processes will be desirable candidates for future electronic packaging technologies. To investigate the ionic migration for thus developed PCB, quite new measurement method has been developed by the authors, which enables real time monitoring of the growth process of ionic migration using AC impedance method. Electric reliability of the newly developed copper printed circuit boards by Japan NEDO project (L/S = 4/6, 8/12, 12/16 μm) using polyimide, etc as the insulating layer have been evaluated under 85°C, 85%RH. The generation of the migration was also tested by conventional time dependence of current under bias of 5.0 V or 100 V. The progress of the migration could be investigated by AC Impedance method (Cole-Cole plots). The degradation of the diameter of the impedance loop suggested the intimation of migrations.