Decapsulation methods for Cu interconnection packages

Decapsulation is the process of removing mold compound from the die surface of a plastic encapsulated device. Typically, the mold compound is removed only in the area above the die and bond wires for failure site isolation and analysis. Hot fuming sulfuric and nitric acids are the most commonly used decapsulating agent. Jet etching system employing these acids or mixture of these acids have become the dominant method for decapsulation. However, due to the increase of the gold price, the IC industry has already begun to switch from gold wire bonding to copper wire bonding. However, the use of copper wire bonding also introduces a problem in failure analysis. The traditional encapuslation techniques of acid results in corrosion. Therefore, many improvements for wet chemical etching and dry etching methods are found such as laser and plasma methods. In this paper, these methods are summerised and further analysis of these methods are discussed, such as comparisons, advantages and disadvantages of these methods. It is a guide for choosing the decapsulation methods and preform accurate IC package analysis.