A thermal–mechanical coupled finite element model with experimental temperature verification for vertically stacked FPGAs

Effect of High Temperature during Electroless Nickel Process

“…Thermal heat problems have been and continue to be an issue of reliability in semiconductor packaging. However, the endless miniaturization in the device size has made the reliability issue very detrimental [3].Hence, it is very challenging for the packaging industry to find solution for heat dissipation while on the other hand, package manufacturers continue their research and development to create thermally enhanced packages. The shift towards flip chip is beneficial as heat dissipation can occur through the bumps, into the substrate and into the printed circuit board (PCB) [4,5].At present, the preferred under bump metallization (UBM) technique for flip chip is electroless nickel immersion gold (ENIG) process or electroless bumping due to its low cost and simplicity [6].…”