Method for producing electroless barrier layer and solder bump on chip

Abstract

The present method for producing a barrier layer and a solder bump on a chip includes: a) providing a silicon chip with a bump base; b) forming a metal pad, e.g. an aluminum pad, on the bump base; c) having the metal pad contact with a solution containing about 120.about.150 g/l NaOH, 20.about.25 g/l ZnO, 1 g/l NaNO.sub.3 and 45.about.55 g/l C.sub.4 H.sub.4 KNaO.sub.6 .multidot.4H.sub.2 O to form thereon a zinc layer, and preferably further containing tartaric acid for reducing a dissolving rate of the metal pad.; d) having the zinc layer contact with a deposition solution to deposit thereon an electroless barrier layer, e.g. an electroless Ni-P layer; and e) dipping the resulting silicon chip into a molten solder bath to form a solder bump on the electroless barrier layer. The present invention is a simple process for manufacturing an electroless Ni-P and a solder bump on a chip.

Dependencies are inferred from the claim text.