Method for forming features upon a substrate

摘要

A material deposition process is disclosed in which apertures of a contact mask used therein have a constricted opening terminating in a 'knife edge' in a sidewall thereof near the top mask side, especially within the top 25% of the mask thickness above the substrate. A process is disclosed in which the mask, in addition, has apertures which have larger dimension lower openings on a bottom side of the mask contacting the substrate than constricted openings near the top side of the mask. Single solder bump and "bump on bump" over BLM (ball limiting metallurgy) processes are disclosed which utilize such contact mask to reduce the damage and detaching of such features during processing and subsequent handling.