Patent ID: 7327029

Claim:
A flip chip integrated circuit device comprising: a package substrate having an upper and a lower surface wherein the upper surface has an inner region of interconnect for receiving the integrated circuit device and a peripheral region; a stiffener ring with upper and lower surfaces wherein the lower surface is attached to the peripheral region of the package substrate upper surface; an integrated circuit die having first and second opposing sides, the first side including a plurality of solder bumps in electrical contact with the inner region interconnect; a heat sink; and a joint layer metallurgically bonded to a first side of the heat sink and the second surface of the die, the joint layer formed by a first metallurgical stack: a titanium adhesion layer formed on the second surface of the die; a barrier layer formed on the titanium adhesion layer, wherein the barrier layer is platinum, nickel, palladium, copper, chromium, or alloys thereof; and a gold-containing layer formed on the barrier layer.