High Density Bga Substrates Fabricated By Laser Technologies

Abstract

High-density hall grid array (BGA) substrates were developed using laser technologies High-energy, short-pulse COz laser was found to be a high-quality, cost-competitive source of processing organic materials. Either a polyimide film oi an aramid-based laminate was used to form advanced BGAs with no through-holes that had been a cause of poor moisture resistance It was found that the tape BGA has sutfcient coplanarity and thinner, lighter features than conventional PBGAs, and also has much higher I-eliability. Independent double-sided traces were obtained using double-sided polyimide tape and processing by a laser to get bonding shelves and ball pads, and an extremely high pin count was obtained When the laser drilling, technology was applied for a double-sided aramid-based laminate, a flip-chip, chip-scale package (CSP) with nonsoldermask-defined ball pads was obtained For multilayer BGA with bonding shelves, the laser was used to forin multiple-tier bonding shelves using an aramid-based laminate The multilayeiboard was attached to a heat slug to form a cavity-down BGA