Effects of hydrothermal aging on the dielectric properties of epoxy molding compounds

We studied the influence of hydrothermal aging on the dielectric properties of epoxy molding compounds used for integrated circuits packaging. Samples were subjected to two different aging (JEDEC 1 and JEDEC 3 procedures, followed by a thermal stress at 240°C for a few minutes). Resistance to aging was studied as a function of crosslinking density. Water uptake increases with crosslinking. Aging leads to a reduction in the dielectric constant and to an increase in the loss factor. Post-mold curing is found to slightly enhance the resistance against hydrothermal aging.