Effectiveness of dilute HF solutions in selectively removing fluorine based plasma etch residue films (PER) with respect to copper has been investigated. PER films were generated by CF4/O2 etching of cresol novolak based photoresist films that were spin coated on copper. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) studies were performed to investigate the PER removal using dilute HF solutions (0.05-0.2 vol. ) and the removal was further confirmed using electrochemical impedance spectroscopy. PER removal rate of ∼60 /min was obtained using 0.2 vol HF (pH 2.8). Higher selectivity of PER/Cu was achieved under deaerated conditions compared to aerated conditions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry