Abstract: A method for packaging a wafer is provided, which includes: providing a bare wafer; forming a plurality of through silicon vias across through the bare wafer, the through silicon vias being filled with a conducting metal; forming a redistribution layer on the bare wafer, the redistribution layer being connected to each of the through silicon vias; performing a chemical mechanical polishing process to planarize a surface of the bare wafer; performing a wafer forming process to treat the planarized bare wafer; forming a metal layer on the wafer after processed; forming a plurality of connection pads on the metal layer, the connection pads being respectively electrically connected to their corresponding through silicon vias; forming a passivation layer on the metal layer; and forming a plurality of solder balls or metal bumps on a backside surface of the wafer through which the processed wafer is electrically connected to a substrate.

Abstract: A method of preventing oxidation of a metal is disclosed. The method includes: placing a metal piece in a vacuum container; injecting hydrogen gas into the vacuum container; heating the metal piece placed in the vacuum container up to 200° C.; cooling the vacuum container and discharging the hydrogen gas; removing the metal piece from the vacuum container; and placing the metal piece in an oxygen-containing environment. An additional inorganic film or organic film is not needed to be used for blocking the oxygen from contacting the metal.