Almit’s LFM 48 N Dipping Paste is an alternative to gel pastes traditionally used in BGA package-on-package (PoP) stacked device applications and is also suited for holding larger area devices that exhibit warpage during reflow. A combination of ultra-fine solder spheres and a flux vehicle optimized for a long open time in a dipping tray, it offers reliability advantages to board assemblers at both solder melt and peak reflow temperatures.

LFM 48 N is designed to deliver consistent dipping transfer characteristics coupled with a strong tack performance to hold large devices firmly in position on high speed pick-and-place systems. It deploys Almit’s low-voiding, thermally stable flux technology for a strong wetting force between molten solder and pad areas. This force is reportedly maintained throughout the entire reflow cycle to eliminate de-wetting tendencies and thereby eliminate the likelihood of open circuit interconnections due to package warpage.

The no-clean, lead free formulation comprises Sn96.5/Ag3.0/Cu0.5 with a solder powder size of 4 to 24 &#181m (Almit size ‘N’). It features a designed open time in a dipping tray of eight hours (at 23°C & 50% RH) and up to eight hours process window time between dipping and reflow. Almit Technology Ltd. East Sussex, UK www.almit.com