Abstract: Disclosed is a stress buffer structure intended to be disposed adjacent a face of a semiconductor substrate. The stress buffer structure includes at least one polymer layer formed on the face of the semiconductor substrate and a plurality of metal plates disposed over the polymer layer, wherein the metal plates is physically and electrically isolated from the bond pads of the semiconductor substrate. The disclosed stress buffer structure provides protection to semiconductor components that are sensitive to stress. Also disclosed are semiconductor packages having the disclosed stress buffer structure and the methods of making the semiconductor packages.

Abstract: Disclosed is an under bump metallization structure including a plurality of metal or metal alloy layers formed on chip bond pads. The disclosed UBM structure has a stress improvement on the semiconductor device because the thickness of the copper-base layer is reduced to between about 0.3 and 10 microns, preferably between about 0.3 and 2 micron. The presence of the pure tin layer prevents oxidation and contamination of the nickel-base layer. It also forms a good solderable surface for the subsequent processes. Also disclosed are semiconductor devices having the disclosed UBM structure and the methods of making the semiconductor devices.