UBM formation for integrated circuits

摘要

A method includes forming a polymer layer over a metal pad, forming an opening in the polymer layer to expose a portion of the metal pad, and forming an under-bump-metallurgy (UBM). The UBM includes a portion extending into the opening to electrically couple to the metal pad.

主权项

1. A method comprising:
forming a post passivation interconnect (PPI) comprising a PPI pad over a dielectric layer; forming a polymer layer over the PPI pad; forming an opening in the polymer layer to expose a portion of the PPI pad, wherein a top surface of the PPI pad, an edge of the PPI pad, and a top surface of the dielectric layer are exposed through the opening in the polymer layer; forming an under-bump-metallurgy (UBM) using chemical plating, wherein the UBM comprises a first portion extending into the opening to contact the top surface and the edge of the PPI pad, and a second portion over and contacting the top surface of the polymer layer; forming a metal conductive layer over the UBM; and performing a thermal step after the forming the metal conductive layer.