Electrochemical Migration of Copper Caused by Volcanic Ash Deposited on Printed Circuit Boards

Review—Electrochemical Migration in Electronic Materials: Factors Affecting the Mechanism and Recent Strategies for Inhibition

“…The study on the effects of contaminants on the ECM of electronic materials is expanded as the exposure of electronics to diverse environment is inevitable. Dust is one of the most commonly found pollutants from the service and industrial environments, 14,43,55 while in harsh environments, more contaminants such as H 2 S, 56 SO 2 , 57 volcanic ash 25,58 and mold 59 are found. The pollutants or the contaminants contain soluble ionic salts and acids which can have severe impacts on the ECM of electronic materials.…”

“…They are found in human handling, manufacturing process, and service environments. 55,58,60,61 Chloride (Cl − ), sulfate (SO 4 2− ) and nitrate (NO 3…”

“…The results of ion chromatography showed that Cl − , SO 4 2− and NO 3 − were highly present in the dust, rainwater and volcanic ash. 55,58,[61][62][63] Minor amount of fluoride (F − ), phosphate (PO 4 3−…”

“…Literature has reported that the presence of Cl − , Br − , SO 4 2− , NO 3 − , SO 2 , H 2 S, dust and volcanic ash increased the conductivity of the electrolyte as a function of concentration. 55,56,58,64,67,68 The conductivity of the electrolyte increases with the number of ionic species dissociated in the solution, which in turn increases the "aggressiveness" of the electrolytes and results in a more rapid anodic dissolution.…”

“…Many researchers reported that the amount of precipitates increased with the concentration of ionic contaminants including but not limited to Cl − , Br − , SO 4 2− , S 2− , NO 3 − , etc. 57,58,64,67,68,79 This is due to the increase in the conductivity and the "aggressiveness" of electrolyte. When the concentration of ionic contaminants reached a certain extent, dendrite could not be observed but only precipitates were produced from the ECM process of metals.…”