Method of forming post passivation interconnects

摘要

A method of forming post passivation interconnects comprises forming a passivation layer over a substrate, wherein a metal pad is embedded in the passivation layer, depositing a first dielectric layer on the passivation layer, applying a first patterning process to the first dielectric layer to form a first opening, forming a first seed layer over the first opening, filling the first opening with a conductive material, depositing a second dielectric layer on the first dielectric layer, applying a second patterning process to the second dielectric layer to form a second opening, forming an under bump metallization structure over the second opening and mounting an interconnect bump over the under bump metallization structure.

主权项

1. A method comprising:
forming a passivation layer over a substrate, wherein a metal pad is embedded in the passivation layer; depositing a first dielectric layer on the passivation layer; applying a first patterning process to the first dielectric layer to form a first opening, wherein the first patterning process is a first laser ablation process, and wherein the first laser ablation process is of a first energy level; forming a first seed layer over the first opening, wherein the first seed layer comprises a first sidewall portion, a second sidewall portion, a bottom portion between the first sidewall portion and the second sidewall portion, and a top portion over a top surface of the first dielectric layer; applying a seed layer removal process to the first seed layer, wherein the first opening between the first sidewall portion and the second sidewall portion and over the bottom portion is free of conductive materials, and wherein non-trench portions of the first seed layer are removed and the seed layer removal process is a laser process having a second energy level; filling the first opening with a conductive material to form a metal line, wherein a top surface of the metal line is level with a top surface of the first dielectric layer; depositing a second dielectric layer on the first dielectric layer; applying a second patterning process to the second dielectric layer to form a second opening; forming an under bump metallization structure over the second opening; and mounting an interconnect bump over the under bump metallization structure, wherein at least one of the first patterning process and the second patterning process is a laser ablation process.