Frictional Characteristic of Polymeric Additive for the Slurry of Chemical Mechanical Planarization Process

In this study, we analyzed the coefficient of friction (COF) of film surface and pad interface during the wafer polishing process to make a correlation with the existence of polyelectrolyte additive in the slurry, which is adsorbed onto the wafer surface. The poly-acrylic acid (PAA) polymer was adde...

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Bibliographic Details
Published in:ECS journal of solid state science and technology 2012-01, Vol.1 (3), p.P101-P106
Main Authors: Kim, Hojoong, Yang, Ji Chul, Lee, Junwye, Park, Sung Ha, Won, Jehyung, Kim, Mingu, Kim, Taesung
Format: Article
Language:English
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Summary:In this study, we analyzed the coefficient of friction (COF) of film surface and pad interface during the wafer polishing process to make a correlation with the existence of polyelectrolyte additive in the slurry, which is adsorbed onto the wafer surface. The poly-acrylic acid (PAA) polymer was added to the slurry in this study because of its proven effect on SiO2 (Oxide)/Si3N4 (Nitride) removal selectivity. Different contact conditions between the wafer surface and the slurry with PAA were established for various PAA concentrations and slurry pHs in polishing experiments. The COF was increased with the adsorption amount of PAA on the wafer surface whereas the dissolved PAA in the slurry served as lubricant that lowered the COF. The lateral force microscope (LFM) with a pad debris particle attached tip, which simulates single asperity contact, confirmed the COF result in a wafer scale experiment. Finally, the direct measurement of absorbed PAA by atomic force microscopy (AFM) in aqueous condition revealed that COF increased with changes of surface morphology and roughness.
ISSN:2162-8769
2162-8777
DOI:10.1149/2.011203jss