TABLE OF CONTENTS As discussed in Chap. 1, the Waste Electrical and Electronic Equipment and Reduction of Hazardous Substances directives require electronic products to be halogen-free and lead-free due to increasing awareness of environmental compatibility. Chip (wafer)-level interconnects with lead-free solder bumps have been discussed in Chap. 2. Wafer-level chip-scale packages (WLCSPs) with lead-free solder bumps on printed circuit boards (PCBs) or the substrate of flip chip in a package have been presented in Chap. 3. Chip (wafer)-level interconnects with solderless bumps have been discussed in Chap. 4 and WLCSPs with solderless bumps on PCBs, tapes, or the substrate of flip chip in a package have been reported in Chap. 5. In this chapter the halogen (Br or Sb)-free flame-retardant molding compounds for plastic quad flat pack (PQFP), plastic ball grid array (PBGA), and mold array PBGA (MAP-PBGA) packages are discussed.
To obtain halogen-free molding compound, it is necessary to maintain flame resistance, even when brominated (Br) epoxy and antimony (Sb) oxide (traditionally used as flame retardants) are eliminated.1 20 This can be achieved by either (1) adding novel flame retardants to the conventional resin, (2) mixing a compound with high filler content to give flame resistance, (3) changing resin construction to inflammable, or (4) combining any of (1), (2), and (3).
Unlike Sn-37Pb solder [melting temperature of 183 C and maximum reflow temperature of 220 C], most of the lead-free solders in the SnAgCuX family have melting temperatures above 213 C. Thus, the maximum reflow temperature of the lead-free solders could be...
