화학공학소재연구정보센터
Applied Surface Science, Vol.210, No.3-4, 190-205, 2003
Localized corrosion effects and modifications of acidic and alkaline slurries on copper chemical mechanical polishing
This study demonstrates the CMP performance can be enhanced by modifying the corrosion effects of acidic and alkaline slurries on copper. A corrosion test-cell with a polishing platform is connected with the potentiostat to investigate the corrosion behaviors of copper CMP in various alumina slurries. Experiments show that the slurry needs to be maintained in acidic pH < 4.56 or alkaline pH > 9.05 surroundings and thus better dispersion of alumina particles and less residual contaminant on copper surface can be obtained. The surface defects after copper CMP using acidic and alkaline slurries are described by pitting corrosion mechanisms, and these mechanisms can be regarded as a basis to modify their corrosion effects. Experimental results indicate that it is necessary to modify the dissolution of HNO3 and oxidization of NH4OH for copper CMP slurries. Consequently, the slurries of 5 wt.% HNO3 by adding 0.1 wt.% BTA or 5 wt.% KNO3 by adding 1 wt.% NH4OH achieve good CMP performance for copper with higher CMP efficiency factor (CMPEF), 1460 and 486, and lower surface roughness (R-q), 4.019 and 3.971 nm, respectively. It is found that AFM micrographs can support the effectiveness of corrosion modifications for copper CMP in various slurry chemistries. (C) 2003 Elsevier Science B.V. All rights reserved.