Effect of chelating agent on benzotriazole removal during post copper chemical mechanical polishing cleaning

•A novel alkaline chelating agent for BTA removal on post Cu CMP is proposed.•The chelating agent shows a good BTA removal ability.•The chelating agent also as function as pH adjuster in clean solution.•The chelating agent has a good stability and it is environment friendly.

During the chemical mechanical polishing (CMP) process of copper, benzotriazole (BTA) is the most commonly used inhibitor, especially in acidic slurry. The post CMP cleaning process is mainly removal of slurry particles and organic residues. The presence of BTA results in a hydrophobic surface of copper, which leads to difficulty in cleaning, and BTA is the main organic residue. The BTA on the copper surface should be removed by using an effective cleaning solution. In this paper, a novel alkaline chelating agent with functionalities of BTA removal was designed for advanced post CMP cleaning solution. The alkaline chelating agent was used as main composition of cleaning agent. When the chelating agent concentration is 100–150 ppm, it can effectively remove Cu–BTA. The removal of BTA is characterized by contact angle measurement, electrochemical methods and static etching rate (SER) measurement. The corrosion protection ability of the cleaning solutions was quantified by potentiodynamic polarization studies. Atomic force microscopy (AFM) measurement was used to monitor the surface quality of copper after cleaning.

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