Via-interconnect ball-grid-array (ViB) fabricated by die-middle PCB-like process

This is the very first package made by PCB-like process with die-middle concept in the industry, and is named as die-middle ViB-W. ViB is a BGA package with via to electrically interconnect the chip I/O pads to package. The suffix W means the ViB is fabricated by wet PCB-like process which interprets lower cost when compared with the wafer Fab-like dry process. Die-middle process has its advantage for potentially high production yield. Thus die-middle ViB-W package possesses high yield/low cost feature which will make it become dominating in low-end to mid-range applications. In this paper, FEA warpage simulation was served to determine the package construction for a ViB-W with 15mm×15mm body size. Two dielectric materials were built into two groups of samples to compare the warpage and reliability performances. Both the groups with 15mm×15mm body size succeeded to meet the requirements of warpage and reliability. Warpage characterization by Shadow Moire was carried out. Warpage behavior is analyzed in details to understand the effect of reflow process and moisture soaking. Bigger body size ViB-W with 24mm×24mm and 29mm×29mm were built to explore the capability boundary of the package construction and BOM designed for 15mm×15mm.