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The Effect of Si Dissolution on the Stability of Silica Particles and its Influence on Chemical Mechanical Polishing for Interlayer Dielectrics

Published

Author(s)

U Paik, J P. Kim, Y S. Yung, T Katoh, Jinkyoo Park, Vincent A. Hackley

Abstract

As a silica slurry for interlayer dielectric CMP is prepared in the alkaline region to accelerate the chemical corrosion process of plasma enhanced tetraethylorthosilicate (PETEOS), Si is dissolved to the point where it will adversely affect the colloidal stability of the silica particles. Under alkaline conditions above pH 9, silica solubility sharply increases and the silica layer is dissolved with the formation of silicic acid and, subsequently, ionized silicate species that results in a decrease of surface potential due to electrical double layer compression. As the silica surface is modified with water-soluble polymer, the decrease of surface potential above pH 9 disappears and results instead in an increase in the stability of silica particles dispersed in the alkaline region. Microscratches on wafers treated with the modified slurry were reduced and the removal rate in CMP processing was increased.
Citation
Journal of the Korean Physical Society
Volume
39
Issue
Suppl. S

Keywords

chemo mechanical polishing, colloidal stability, disolution, interlayer dielectrics, passivation, silica

Citation

Paik, U. , Kim, J. , Yung, Y. , Katoh, T. , Park, J. and Hackley, V. (2001), The Effect of Si Dissolution on the Stability of Silica Particles and its Influence on Chemical Mechanical Polishing for Interlayer Dielectrics, Journal of the Korean Physical Society (Accessed April 16, 2024)
Created November 30, 2001, Updated October 12, 2021