Effect of pH in Ru Slurry with Sodium Periodate on Ru CMP
- 1 January 2009
- journal article
- Published by The Electrochemical Society in Journal of the Electrochemical Society
- Vol. 156 (3), H188-H192
- https://doi.org/10.1149/1.3058594
Abstract
In this study, sodium periodate (NaIO4)(NaIO4) was chosen as both oxidant and etchant on ruthenium (Ru) chemical mechanical planarization (CMP) slurry for the formation of Ru bottom electrodes in dynamic random access memory capacitors. The effect of NaIO4NaIO4 on etching and polishing behavior was investigated as a function of slurry pH. Below pH 7.5, the high static etch rate was measured due to the dissolution of soluble RuO4RuO4 . Above pH 7.5, the static etch rate decreased due to the formation of insoluble RuO2⋅2H2ORuO2⋅2H2O and the depletion of periodate ions. The highest etching of 20nm∕min20nm∕min was obtained at pH 6. In a slurry of 0.1M0.1M NaIO4NaIO4 and 2wt%2wt% alumina particles at pH 6, the removal rate of Ru was about 130nm∕min130nm∕min . Even though the highest removal rate was obtained at pH 6, Ru overetching occurred on Ru-patterned wafers due to the high static etch rate of Ru. A selectivity of Ru to oxide of about 23:1 was achieved at pH 8–9. In slurry of pH 9, the planarity and isolation of each capacitor were reached successfully because Ru overetching was prevented due to a low etch rate of Ru.Keywords
This publication has 17 references indexed in Scilit:
- Effect of Sodium Periodate in Alumina-Based Slurry on Ru CMP for Metal–Insulator–Metal CapacitorElectrochemical and Solid-State Letters, 2008
- MIM capacitors using amorphous high-k PrTixOy dielectricsMicroelectronic Engineering, 2005
- Combining Ta[sub 2]O[sub 5] and Nb[sub 2]O[sub 5] in Bilayered Structures and Solid Solutions for Use in MIM CapacitorsJournal of the Electrochemical Society, 2005
- Degradation of 4-chloro-2-methylphenol in aqueous solution by UV irradiation in the presence of titanium dioxideApplied Catalysis B: Environment and Energy, 2004
- Damascene Cu electrodeposition on metal organic chemical vapor deposition-grown Ru thin film barrierJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2004
- Development of novel process for Ru CMP using ceric ammonium nitrate (CAN)-containing nitric acidApplied Surface Science, 2004
- Investigation into patterning of a stack-type Ru electrode capacitorMicroelectronic Engineering, 2003
- Electrodeposition of Copper Thin Film on RutheniumJournal of the Electrochemical Society, 2003
- Deposition and Characterization of Ru Thin Films Prepared by Metallorganic Chemical Vapor DepositionJournal of the Korean Physical Society, 2000
- Progress in the developments of (Ba,Sr)TiO3 (BST) thin films for Gigabit era DRAMsMaterials Chemistry and Physics, 2000