Small spot analysis of printed circuit board solder

With the increased concern over the proper use of solder paste and disposal of used printed circuit boards, as well as in forensic science, the need to accurately analyze and identify solder alloys has become more important.

XRF measurements of small fragments of printed circuit boards, particularly useful in forensics, can be performed without including surrounding materials that would risk misidentifying the solder. (Figure 1)

Figure 1

This is possible by combining the Semi-Quantitative (SQX) analysis with mapping and small spot/discrete area capabilities of the Rigaku ZSX Primus and ZSX Primus II WDXRF systems. Table 1 shows the results of the analysis of a sample of NC254 SAC305 alloy, which has a nominal composition of Cu: 0.5%, Ag: 3.0% and Sn: 96.5%. It is readily apparent that an accurate identification of solder paste alloys can be made. 

Table 1

Also evident are the opportunities that this capability offers the forensic scientist.