The role played by mould in the electrochemical migration (ECM) behaviour of an immersion silver finished printed circuit board (PCB-ImAg) under a direct current (DC) bias was investigated. An interesting phenomenon is found whereby mould, especially Aspergillus niger, can preferentially grow well on PCB-ImAg under electrical bias and then bridge integrated circuits and form a migration path. The cooperation of the mould and DC bias aggravates the ECM process occurring on PCB-ImAg. When the bias voltage is below 15 V, ECM almost does not occur for Ag coating. Mechanisms that explain the ECM processes of PCB-ImAg in the presence of mould and DC bias are proposed.

研究了模具在直流（DC）偏压下在浸银精制印刷电路板（PCB-ImAg）的电化学迁移（ECM）行为中所起的作用。发现了一个有趣的现象，模具尤其是黑曲霉可以在电偏压下优先在PCB-ImAg上良好生长，然后桥接集成电路并形成迁移路径。模具和直流偏置的配合加剧了在PCB-ImAg上发生的ECM工艺。当偏置电压低于15 V时，Ag涂层几乎不会发生ECM。提出了解释存在模具和直流偏置的情况下PCB-ImAg的ECM过程的机制。