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

Published

December 1, 2001

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

Pub Type

Journals

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 19, 2024)