Method for joining an integrated circuit

The present invention relates generally to methods for forming electrical interconnections. The present invention relates more particularly to a method for joining an integrated circuit or the like to a flexible circuit, wherein contact bumps that facilitate electrical interconnection have a profile or cross-sectional configuration which mitigates stresses therein while facilitating penetration of an oxide layer formed upon mating contact pads and wherein heat is applied so as to simultaneously cure a pre-applied epoxy underfill and fuse the contact bumps to the contact pads. A method for attaching an integrated circuit to a flexible circuit which includes the acts of providing an integrated circuit having a plurality of contact pads formed upon a surface thereof; providing a flexible circuit possessing a plurality of contact bumps formed integral to a surface area; and attaching the integrated circuit to the flexible circuit by fusing at least some of the contact bumps of the flexible circuit to at least some of the contact pads of the integrated circuit. The contact bumps have a shape which mitigates local stress buildup within the contact bumps after attachment of the contact bumps to the contact pads, so as to enhance the reliability of the electrical connection.