Reliability Analysis and Accelerated Statistical Model of CNC PCB for Electrochemical Migration

Abstract

The effect of conductor spacing and applied voltage on the insulation performance of printed circuit board (PCB) has been investigated under temperature-humidity-bias (THB) conditions in this paper. Based on the electrochemical migration failure mechanism, this paper proposes an accelerated statistical model, which includes a life-stress relationship model and a life distribution model. The accelerated statistical model can effectively quantify the effect of concurrent conductor spacing and applied voltage on the characteristic life of the PCB. Because THB test can produce less life data in limited test period, an accelerated degradation theory is applied for the modeling research. In addition, a methodology on how to verify the accelerated statistical model for the CNC PCB is introduced. In the case of small samples, the least square regression method is applied for parameter calculation due to its high precision. Furthermore, the residual analysis is carried out to check the fitting effect. The results show that the accelerated statistical model can describe the life characteristics of CNC PCBs preferably under the comprehensive action of conductor spacing stress and applied voltage stress.