Low cost method for forming elevated metal bumps on integrated circuit bodies employing an aluminum/palladium metallization base for electroless plating

摘要

Elevated metal contact bumps are provided on a microelectronic semiconductor circuit, with the use of aluminum-palladium metallization as a base for selective electroless plating. The aluminum and palladium are preferably deposited sequentially in a single operation, i.e., without exposing the aluminum surface to the atmosphere. The aluminum-palladium film is then patterned in a single step, using an etchant which attacks both metals at substantially the same rate. The metal pattern is then covered with an insulation layer wherein apertures are opened to expose palladium at selected sites for immersion in an electroless plating bath of ionic Cu or Ni for bump formation.