Effects of Temperature and Operation Parameters on the Galvanic Corrosion of Cu Coupled to Au in Organic Solderability Preservatives Process

Abstract

In this work, we quantitatively examined the effects of temperature and operation parameters such as anode (Cu) to cathode (Au) area ratio, stirring speed, and Cu ion concentration on the galvanic corrosion kinetics of Cu coupled to Au (i(couple) (Cu-Au)) on print circuit board in organic solderability preservative (OSP) soft etching solution. With the increase of temperature, galvanic corrosion rate (i(couple) (Cu-Au) was increased; however, the degree of galvanic corrosion rate (i(couple) (Cu-Au) - i(corr) (Cu)) was decreased owing to the lower activation energy of Cu coupled to Au, than that of Cu alone. With the increase of area ratio (cathode/anode), stirring speed of the system, i(couple) (Cu-Au) was increased by the increase of cathodic reaction kinetics. And i(couple) (Cu-Au) was decreased by the increase of the Cu-ion concentration in the OSP soft etching solution.