METHOD FOR FORMING SOLDER BUMP FOR SEMICONDUCTOR PACKAGE

摘要

PURPOSE: A method for forming a solder bump for semiconductor package is provided to improve a cutting mode of a bump and reliability of the semiconductor package by filling robust material such as polyimide into an undercut portion between a solder and a polyimide layer. CONSTITUTION: A final Cu line(14) instead of an insulating layer(12) is formed on an insulating substrate(10) by performing a damascene process. A protective layer(16) is formed thereon in order to expose a part of a surface of the final Cu line(14). An Al pad(20) is formed on the protective layer(16) by inserting a metal barrier(18). A polyimide layer(24) is formed on the above structure in order to expose a surface of the Al pad(20) of an upper side of the final Cu line(14). An UBM(Under Bump Metal)(26) is deposited thereon by using a sputtering method. The UBM(26) is formed with Cr(26a), phased Cr/Cu(26b), and Cu(26c). A resist pattern is formed on the UBM(26) in order to open a solder bump formation portion. A solder is plated on an open portion by using an electro-plating method. The unnecessary UBM(26) is etched. A polyimide layer is coated thereon. A hemispheric bump(28a) is formed by performing a reflow process.