Issue link: https://iconnect007.uberflip.com/i/1002143
34 PCB007 MAGAZINE I JULY 2018 also indicates a discrepancy between the crit- ical and non-critical solder mask. Due to the complexity of the solder mask chemistry, this method may be used as a fingerprinting tech- nique to direct further analysis. Figure 4 compares a cross-section of the pop- ulation whilst Figure 5 focuses on the compar- ison of the critical population members. It can be demonstrated that the critical solder masks exhibit similar absorption signals at the almost Figure 4: Comparison of critical solder mask to non-critical and reference. Figure 5: Similarities of all critical solder masks.