Patent ID: 8383505

Claim:
A method of manufacturing a solder ball contact, said method comprising: forming, sequentially, a base layer, a conductive layer, and a second insulating layer over a first insulating layer, said first insulating layer including a first via to a metal pad formed on an integrated circuit (IC) chip; forming a first photoresist, including a second via centered on and having a greater diameter than said first via, to expose a first portion of said second insulating layer within said first and second vias; removing said first portion of said second insulating layer; forming a barrier layer on said conductive layer within said first and second vias; forming a solder contact on said barrier layer within said first and second vias; removing said first photoresist; forming a second photoresist on said solder contact and a second portion of said second insulating layer that surrounds said solder contact; removing said second insulating layer, said conductive layer, and said base layer not covered by said second photoresist; removing said second photoresist to expose said solder contact, which overlies an under bump metallurgy (UBM) structure comprising said barrier layer, said conductive layer, and said base layer; and reflowing said solder contact to form a solder ball contact.