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Your search keyword '"BABU, S."' showing total 27 results
Start Over Author "BABU, S." Journal journal of the electrochemical society
27 results on '"BABU, S."'

24. Selective Chemical Mechanical Polishing of Silicon Dioxide over Silicon Nitride for Shallow Trench Isolation Using Ceria Slurries.

Author

Veera, P. R. Dandu, Peddeti, Shivaji, and Babu, S. V.

Subjects
ELECTROCHEMICAL research, SILICA, SILICON nitride, OXIDES, SLURRY, AMINES
Abstract

For the shallow trench isolation process, in which a thin silicon nitride film acts as a polish stop layer, a polishing slurry with a high oxide to nitride removal rate selectivity is required to remove the overburden oxide. In this work, we show that using ceria-based slurries and only 0.05% of any one of three different cyclic amine additives, namely, pyridine HCI, piperazine, and imidazole, very low nitride (<2 to 3 nm/mm) and high oxide (∼350 nm/mm) removal rates can be obtained for blanket films. The role of these additives in the slurry toward achieving the desired removal rate selectivities of silicon dioxide over silicon nitride is discussed considering pyridmne HCI as an example, using zeta potential, contact angle, adsorption isotherm, and thermogravimetric analysis data. [ABSTRACT FROM AUTHOR]

Published
2009
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25. Selective Polishing of Polysilicon during Fabrication of Microelectromechanical Systems Devices.

Author

Veera, P. R. Dandu, Natarajan, A., Hegde, S., and Babu, S. V.

Subjects
GRINDING & polishing, SILICON, MICROELECTROMECHANICAL systems, SLURRY, SILICON nitride, SILICA, INFRARED spectroscopy, CONTACT angle, AMINO acids
Abstract

During a typical microelectromechanical systems device fabrication process, a polysilicon top layer has to be polished with a slurry that yields a high polysilicon removal rate (0.5 μm/min or more) and a high selectivity over the underlying silicon dioxide and silicon nitride layers (>50:1). In this work, polysilicon polish rates as high as 550 nm/mm and selectivity over silicon dioxide and nitride of ∼ 130 and ∼ 260, respectively, have been achieved using colloidal silica and calcined ceria-based slurries containing arginine or lysine mono hydrochloride, at 4 psi down pressure. At 8 psi, polysilicon polish rates close to 900 nm/mm and selectivities over both oxide and nitride that are close to 300 have been achieved. ξ potential, infrared spectroscopy, and contact angle data are used to explain the role of the amino acid additives in achieving the desired removal rate selectivities of polysilicon over silicon dioxide and silicon nitride. [ABSTRACT FROM AUTHOR]

Published
2009
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27. Role of the Functional Groups of Complexing Agents in Copper Slurries

Author

Patri, Udaya B., Aksu, Serdar, and Babu, S. V.

Abstract

We investigate the role of –NH2and –COOH functional groups of complexing agents in H2O2-based slurries in controlling copper (Cu) removal rates. Slurries containing complexing agents with two of the same functional groups (succinic acid: HOOC–CH2CH2–COOH, ethylene diamine: H2N–CH2CH2–NH2) and a complexing agent containing one each of the functional groups (β-alanine: H2N–CH2CH2–COOH), all with the same carbon chain length, were investigated. Along with dissolution and disk polish experiments, potential–pH diagrams were constructed for these three systems in the presence of H2O. The dissolution and polish rates are consistent with the known activity of carboxylic acids (with –COOH groups) at acidic conditions and that of amines (with –NH2groups) in an alkaline environment. The observed trends in the removal rates with all these slurries are explained using potential–pH diagrams, UV/visible spectra, and electrochemical experiments. When compared to glycine (H2N–CH2–COOH), β-alanine (H2N–CH2CH2–COOH)produced higher removal rates at acidic pH values and lower removal rates at alkaline pH values. Finally, succinic acid and β-alanine-based slurries were found to result in lower dissolution rates and higher polish rates compared to glycine-based slurries at pH 4.

Published
2006
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