Achievement of high planarization efficiency in CMP of copper at a reduced down pressure
| Autor: | S. Pandija, Suryadevara V. Babu, Dipankar Roy |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Benzotriazole
Materials science Passivation Low-k dielectric chemistry.chemical_element Condensed Matter Physics Copper Atomic and Molecular Physics and Optics Surfaces Coatings and Films Electronic Optical and Magnetic Materials Contact angle chemistry.chemical_compound Chemical engineering chemistry Chemical-mechanical planarization Electrical and Electronic Engineering Dissolution Fumed silica |
| Zdroj: | Microelectronic Engineering. 86:367-373 |
| ISSN: | 0167-9317 |
| DOI: | 10.1016/j.mee.2008.11.047 |
| Popis: | We report improved planarization efficiency (ratio of step height reduction and removed layer thickness) in chemical-mechanical planarization (CMP) of copper lines at a down pressure of 2 psi. The CMP slurry used to achieve these results contains fumed silica particles (abrasive), @b-alanine (surface complexing agent) and H"2O"2 (oxidizer), combined with dissolution inhibiting ammonium dodecyl sulfate (ADS) and/or low concentrations (@?1 mM) of benzotriazole (BTAH) at a solution pH of 4.0. When only ADS or BTAH is used, Cu dissolution rate is reduced, but at the cost of somewhat low planarization efficiency. Combination of ADS (typically 3mM) and BTAH (@?1mM) in the slurry significantly improves both the surface polish rates and the planarization efficiency. The processed surface (examined by optical profilometry) is noticeably defect-free for this particular system. The mechanisms of surface dissolution and passivation are discussed, and contact angle data are used to elucidate the surface passivating nature of the inhibitor films. The results presented here are relevant for further developments in the area of low pressure CMP of Cu lines overlying fragile low-k dielectrics in the new interconnect structures. |
| Databáze: | OpenAIRE |
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