Development of an eco-friendly copper interconnect cleaning process

This paper reports the development of an eco-friendly, low-cost and clean wet cleaning process in forming copper interconnections, especially on a copper surface at the bottom of the via. From analysis and electrical data, the components of post-etch residues are mainly formed by copper fluorides, copper oxides and silicon oxides. Therefore, diluted inorganic acid solutions are used to remove these polymers and a diluted amine solution is used to stabilize the copper surface after cleaning. These chemicals are treated by an effluent treatment facility, and are very cheap and clean. In the results of post-cleaning, the analysis data shows that the residues are removed, and the electrical data such as via chain yield, electro migration, etc., shows good performance.