Issue link: https://iconnect007.uberflip.com/i/992528
64 PCB007 MAGAZINE I JUNE 2018 ly, if the broken interface contained more than 25% IMC or voids, zero points was assigned. For example, if all 20 balls were broken com- pletely at the solder without IMC appearance, total point results equal 100 since five points were assigned for each ball. Total BP points are shown in Table 6 for each deposit and each reflow condition. For ENEPIG deposit with Pd-P, BP points were 100 even when the reflow condition was 5x at 260°C, which condition is too severe and usually not required. IGEPIG and ENEPIG with pure Pd deposits were also 100 except for 5x reflow at 260°C. The important thing is that SJR of IGEPIG was al- most same with that of EN- EPIG with pure Pd, which is entirely acceptable for indus- try, and was better than that of EPIG deposit. The cross-section image of IMC was observed to consider difference of SJR when reflow con- dition was one time at 260°C. From IMC ob- servation results of Figure 4, (Cu, Ni) 6 Sn 5 was formed as layer 1 and Ni+Ni 3 P was formed near Ni-P layer as layer 2 when ENEPIG de- posit was used both with Pd-P or pure Pd [1, 2,3) . On the other hand, Cu 6 Sn 5 was formed as layer 1 and Cu 3 Sn was formed near Cu layer as lay- er 2 when EPIG or IGEPIG deposit was used [4) . IMC which formed from ENEPIG deposit was Table 6: Ball pull points of each deposit. Figure 4: Cross-section image of IMC; (a) ENEPIG with Pd-P, (b) ENEPIG with pure Pd, (c) EPIG, and (d) IGEPIG, one time reflow at 260°C.