Validation of warpage limit for successful component surface mount (SMT)

Optimal combination of soldering conditions of BGA for halogen-free and lead-free SMT-green processes

“…In order to reduce interference and variance of the experiments to the least, some restriction conditions are set, such as using organic solderability preservative (OSP) for PCB surface treatment, using copper as mother material of the pad, adopting circular shape for the pad, its diameter being fixed at 0.36 mm, using non-oxidized and pollution-free pad, the diameter of BGA solder ball being 0.42 mm, the warpage [14] range of BGA being 50.15 mm, the reflow oven used being nitrogen (N 2 ) reflow oven with residual oxygen 300-500 ppm, the solder paste used being lead-free and halogen-free Sn3Ag0.5Cu, the opening of printing stencil being made by laser engineering method, the thickness of printing stencil being 0.12 mm, the stencil tension being 40-45 newtons (Nt), the accuracy of mounter being ensured to be above 3 sigma, the temperature of experimental environment being controlled at 23-26°C, and the relative humidity range being at 50-60%.…”

Quality and reliability challenges for ultra mobile computing and communication application processor packaging

“…In addition, warpage is a function of temperature so the warpage shape and magnitude may not match room temperature measurement as shown in an example illustrated in Figure 9. Characterizing warpage vs. temperature is important to ensure good interconnect yield and reliability in additional to reduce room temperature warpage and collect SMT yield data [21][22][23]. A reflow temperature flatness requirements spec is released by JEDEC as an alternative to room temperature warpage requirements [24].…”

Package-on-Package (PoP) warpage characteristic and requirement

“…Based on JIETA specification [7] and experimental work from Cho and Amir et.al. [8], both concluded that there are sets of warpage flatness requirement at elevated temperature that depends on the gap formed between the package joints and board pads. The iNEMI technology roadmap [9] gathered a more conservative high temperature warpage allowable for range of ball pitch and diameter.…”