Tribo-Electrochemical Characterization of Brush-Scrubbed Post-CMP Cleaning: Results for Tartrate-Supported Removal of Residual Oxides from Copper Films
Wafer cleaning after chemical mechanical planarization (CMP) is a critical processing step for copper metallization in integrated circuits. Post-CMP cleaning (PCMPC) commonly combines surface (electro)chemistry with the tribology of brush scrubbing to remove CMP residues from wafer surfaces. While t...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Lubricants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4442/13/7/301 |
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| Summary: | Wafer cleaning after chemical mechanical planarization (CMP) is a critical processing step for copper metallization in integrated circuits. Post-CMP cleaning (PCMPC) commonly combines surface (electro)chemistry with the tribology of brush scrubbing to remove CMP residues from wafer surfaces. While the complex mechanisms of brush-operated PCMPC are supported by this combination, the conventional electroanalytical methods of assessing PCMPC efficiency are typically operated in the absence of surface brushing. Using a model experimental system with tartaric acid (TA) as a cost-effective cleaner of Cu-oxides, we illustrate here how post-CMP Cu samples can be electrochemically examined using brush cleaning to design/assess PCMPC test solutions. A pH-neutral cleaning solution is employed, where TA also serves as a partial dissolution suppressor of Cu, and CMP-treated wafer samples are scrubbed with a commercial PCMPC brush as sample surfaces are simultaneously probed with electrochemical measurements. The results show the active roles of tribology/lubrication and surface chemistry in the removal of CMP residues. The electrochemically determined residue removal efficiencies of PCMPC are found to be ~97% and ~56% in the presence and in the absence of surface brushing, respectively. The implications of these findings are explored in the general context of evaluating PCMPC formulations. |
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| ISSN: | 2075-4442 |