Method for forming flip chip bump and ubm for high speed copper interconnect chip using electroless plating method

Abstract

A method for forming flip chip bumps or UBM for a high speed copper interconnect chip, and more particularly to a method for forming a flip chip bump or UBM of copper/nickel, copper/nickel/copper or etc. which are carried out by a subsequent process of electroless copper plating and electroless nickel plating on a copper I/O pad. According to the method, both of electroless copper and nickel plating methods are used for forming electroless copper/nickel bumps of a copper interconnect chip so that advantages of the electroless copper plating, i.e. excellent selectivity and adhering strength to the copper chip pad and an advantage of the electroless nickel plating, i.e. excellent plating rate can be achieved at the same time.