Thermo-Oxidative Degradation and Decomposition of Brominated Epoxy FR-4 Laminates

The brominated epoxy is commonly used in the circuit boards to achieve the 94V-O flame retardancy per Underwritters Laboratories (UL) tests. However, the bromine-containing epoxy has been reported to be less stable at high temperatures than the non-brominated resin sup [1,2]. This thermal instability of the brominated epoxy laminates is one of the major concerns in the printed circuit board industry, since the laminates are often required to withstand multiple high temperature excursions up to 260degreesC in the printed circuit manufacturing and assembly processes.