Reliability testing and data analysis of an 1657CCGA (ceramic column grid array) package with lead-free solder paste on lead-free PCBs (printed circuit boards)

In this study, the thermal cycling test of the 1657CCGA package with 95.5wt%Sn3.9wt%Ag0.6wt%Cu and 63wt%Sn37wt%Pb solder pastes on lead-free PCBs with HASL (hot-air solder leveling) CuSn, NiAu (electroless Ni and immersion Au, ENIG), and Entek OSP (organic solderability preservative) surface finishes are performed. The test stopped at 7500 cycles (0 to 100/spl deg/C, 40-minute cycle). The test data is best fitted to the Weibull life distribution. Also, the sample mean, population mean, sample characteristic life, true characteristic life, sample Weibull slope, and true Weibull slope for the 1657CCGA package on the lead-free PCBs are provided and discussed. Furthermore, the relationship between the reliability and the confidence intervals for the life distribution is established. Finally, the confidence level for comparing the quality (mean life) of the CCGA solder joints is determined.

(1) Introduction

In many applications such as workstations, high-end computers, and telecommunications, the IC chip sizes are very big, the on-chip frequency and power dissipation are very high, and the number of chip I/Os is very large. The 1657CCGA (ceramic column grid array) package developed by IBM as shown in Figure 1 and 2 is one of the best packaging candidates for housing these kinds of chips [1]– [8]. Just like all other IC packages, the CCGA is currently, soldered on the PCB with SnPb solder. However, due to the lead-free regulations [9]– [15], after July I, 2006, the CCGA may have to be soldered onto the PCB with lead-free solders. Today, the leading lead-free solder candidates are the Sn(3–4)wt%Ag(.5–1)wt%Cu solder family.