A stress decoupling structure provided underneath the under-ball-metallurgy (UBM) pads of a flip-chip bonding integrated circuit (IC) chip enhances the cyclic fatigue life of the solder joints formed by the solder bumps on the IC chip. The stress decoupling structure is formed from an elastic polymer layer provided over the active surface of the integrated circuit chip. A plurality of conductive metal posts are formed in the elastic polymer layer, extending between one of the contact pads on the active surface of the chip and one of the UBM pads. Solder bumps provided on the UBM pads form the solder joints between the chip and the next level interconnect structure.