A new flame retardation system for epoxy molding compounds was investigated for application to semiconductor packaging. By adding a small volume of calcium borate as a flame retardant, the flammability of the epoxy molding compound decreased. The flammability was not decreased proportionally with the volume of calcium borate. To further enhance flammability, an excess amount of phenolic resin was added to the epoxy molding compound. With the effects of calcium oxide and the excess phenolic resin, we developed an epoxy molding compound which has a flame-retardant level sufficient to satisfy the V-0 classification of the UL94 rating. We also found that calcium oxide in the calcium borate accelerates the curing reaction of epoxy compounds due to its absorption of water from the phenolic resin hardener. Calcium hydroxide formed from calcium oxide and water was also considered to contribute to the decrease in flammability by releasing water at high temperatures. The flame retardation mechanism of this developed epoxy compound is also discussed. Finally, the developed epoxy compound was proved to have suitable moldability, mechanical properties, and durability for use as semiconductor packaging.