Spectroscopic investigation of oxidized solder surfaces

Abstract For further understanding of the discoloration of solder surfaces due to oxidation during the assembly and operation of electronic devices, UV–vis and X-ray photoelectron spectroscopic analyses were applied to evaluate the degree of discoloring and identify the surface oxides. The decrease in reflectance of the oxidized solder surface is related to SnO whose absorption band is located within the visible region. A trace of P can effectively depress the discoloration of solders under both solid and semi-solid states through the suppression of SnO.