Underfill Material for BGA and CSP Devices The Loctite 3508 one-component epoxy is pre-applied to the board at the corners of the CSP pad site using a standard dispensing system. Unlike capillary flow underfills that require dedicated equipment and subsequent process steps, this epoxy can be applied in-line with existing capital equipment with curing taking place during the normal solder reflow process. Loctite 3508 was specifically designed to be compatible with the material curing during solder reflow and the higher temperature requirements of lead-free manufacturing. The Cornerbond system is lead-free compatible, adaptable to in-line processing, and enables total ball collapse and the self-alignment properties necessary to compensate for slight component-to-pad misalignment during device placement. The epoxy is also reworkable, which allows manufacturers to remove defective devices without having to scrap an entire assembly. Henkel, Irvine, CA, www.henkel.com/electronics.