Effects of K3[Fe(CN)6] slurry's pH value and applied potential on tungsten removal rate for chemical-mechanical planarization application
Chemical-mechanical planarization (CMP) is an important process for building multilevel interconnections for electronic devices. Directly planarizing tungsten, which is used as via or contact in microelectronic circuits, by wear is a difficult process because of its high hardness. Therefore, an effective approach has been developed to facilitate planarizing tungsten surface by removing a continuously growing passive film on tungsten when exposed to a low-pH potassium ferricyanide slurry. Since the passive film is softer than tungsten, this chemical mechanical planarization process is effective. In this work, in order to determine effects of corrosion and wear on tungsten removal rate, attempts were made to investigate corrosion, wear, and corrosive wear behavior of tungsten in K3[Fe(CN)6] slurries. Electrochemical and tribological experiments were carried out for different slurry pH values and potentials using a rotating pin-on-disc tribometer. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize surface films formed at the different pH levels and potentials. It was demonstrated that the tungsten removal rate increased with increasing slurry pH and potential. Mechanisms involved are discussed.
- Research Organization:
- University of Alberta, Edmonton, Alta., Canada T6G2G6; Albany Research Center (ARC), Albany, OR, USA; Intel Corporation, USA
- Sponsoring Organization:
- Alberta Energy Research Institute; Nature Science and Engineering Research Council of Canada; USDOE - Office of Fossil Energy (FE)
- OSTI ID:
- 893076
- Report Number(s):
- DOE/ARC-2005-005
- Country of Publication:
- Netherlands
- Language:
- English
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