Challenges and solutions of post etch post ash residue removal

Wet cleaning technology plays a critical role in IC industry, and takes up around 30% of whole process. With the critical dimension continuous shrinking, there are many additional requirements exposed. Among BEOL (back end of line) post etch post ash residue removal technology, galvanic corrosion elimination, low geometry via cleaning, pad crystal defect reduction and environment friendly are the major requirements. But the conventional cleaning technologies are challenging to meet them. In this paper, we will share our studies of key aspects in post etch post ash residue removal system, such as: surface energy reduction, substrate materials protection and being environmental conscientious. By those studies, the challenges are addressed, and improved performance for both organic and inorganic residues removal is achieved. Further more, environmental distress caused by chemistry is reduced.