Resolution of aluminium bond pad corrosion.
New, Chi Lin.
Date of Issue2010
School of Electrical and Electronic Engineering
Aluminum bond pad corrosion is a fundamental and yet detrimental problem commonly seen in the semiconductor industry. It compromises the quality of the bond pad surface prior to chip assembly which will lead to IC malfunctioning in the short term; and a long term packaging reliability problem known as Non-Stick-on-Pad (NSOP). Corrosion normally comes in two forms; one of which is known as the galvanic corrosion and the other is fluorine-based corrosion. Galvanic corrosion arises from the presence of a galvanic couple and an electrolyte. One metal erodes in preference to the other depending on the electrode potentials between the couple. Fluorine-based corrosion attributes to the traces of fluorine contaminant on the metal surface which reacts with atmospheric moisture to dissolve Aluminum. Both mechanisms will see erosion on Aluminum surface that exacerbates with time. Some standard protocols have already been put in place across the industry to prevent bond pad corrosion. However, excursions and special process integrations do result in such undesirable circumstances from time to time.
DRNTU::Engineering::Electrical and electronic engineering
Nanyang Technological University