To evaluate the oxide formation characteristics of tin (Sn) as a function of conditioning treatment and define a conditioning methodology that rapidly produces a tin oxide thickness and oxide species morphology similar to those formed in ambient oxidation.
Electrochemical reduction analysis and scanning electron microscopy techniques were utilized to identify tin oxide species and oxide quantities on tin samples which were subjected to a variety of conditioning methodologies.
Tin oxide species were identified and oxide quantities measured. Comparisons of tin oxide species/quantities were completed for the different conditioning methodologies used and for other industry oxide investigations. The following conclusions were reached: all conditioning methodologies produced both SnO and SnO2 tin oxide species; steam conditioning produced the thickest oxides; the conditioning methodologies investigated were found to produce oxide thicknesses similar to those formed under ambient conditions.
Further investigation would be beneficial using this study as a foundation. Additional conditioning methodologies and a larger selection of various tin surfaces would provide a future understanding of the impact of oxide species and thickness on solderability.
The electronics industry has attempted to “predict” a surface's susceptibility to oxidation by using accelerated conditioning techniques. An understanding of the formation of tin oxidation products created by accelerated conditioning techniques could be highly beneficial to the electronics industry. The standardization and use of a realistic accelerated conditioning technique would reduce testing cycle time, increase the predictability and consistency of test results, and lower testing costs.
This paper was incorporated into an original electronics manufacturer's solderability testing/analysis procedures, and the results are being utilized by the electronics industry solderability specification task groups/committees.
