The presence of bromine (Br) in flame retardant epoxies accelerates the degradation of gold-aluminum wire bonds. This experiment tests degradation by adding 5 wt.% 2,6-dibromophenol to the regular molding compound and holding thermal aging at 175°C and 205°C in ovens for up to 1,008 h. The intermetallic degrading microstructure was examined at different aging times. In order to better understand the mechanism behind the degradation, bulk Au 4 Al and Au 5 Al 2 single-intermetallic phases were prepared and reacted with molding compound at 205°C. The reactions were analyzed by a JEOL (Japan Electron Optics Ltd., Tokyo) Superprobe JXA-8900R under wavelength-dispersive spectrometry of x-ray mode. A similar chloride degrading study was performed by adding Tetrachlorobisphenol A to the regular molding compound. The results show that Br attacked the Au 4 Al phase first and then the Au 5 Al 2 phase. The chloride reacted with the Au 4 Al phase only.