IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Manufacturing Science and Technology Monday Sessions
       Session MS-MoP

Paper MS-MoP2
In-Situ EIS Approaches to the Copper CMP Slurry Characterization

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Aspects of Manufacturing Science and Technology Poster Session
Presenter: S.-Y. Chiu, National Chiao Tung University, Taiwan, R. O. C.
Authors: S.-Y. Chiu, National Chiao Tung University, Taiwan, R. O. C.
J.-W. Hsu, National Tsing Hua University, Taiwan, R. O. C.
Y.L. Tasi, National Tsing Hua University, Taiwan, R. O. C.
Y.-L. Wang, Institute of Materials Science and Engineering, Taiwan, R. O. C.
M.-S. Tsai, National Nano Device Laboratories, Taiwan, R. O. C.
H.C. Shih, National Tsing Hua University, Taiwan, R. O. C.
M.-S. Feng, National Chiao Tung University, Taiwan, R. O. C.
Correspondent: Click to Email
In the chemical-mechanical polishing study, slurry chemistry in chemical-mechanical polishing of Cu thin film has been evaluated in various slurries. Various types of oxidizer and inhibitor were changed in the concentration and slurry pH were investigated. In nitric acid based slurry, with both H+ and NO3- present, it provides a corrosion environment for copper. With citric acid present in slurry system, it plays a role of formation a native passivation film on the surface. The polishing rate of copper increases as the concentration of HNO3 increases or citric acid decreased. In H2O2 based slurry, H2O2 both dissolute of copper and form a cupreous oxide passivation surface. H2O2 is a strong oxidizer, it provides a potential to copper to be oxidized, maybe cupric ion or cuperous oxide simultaneously. For small amount of H2O2 adding in acidic region, it increase the dissolution the copper that increase the polishing rate of copper. With more H2O2 in slurry, the oxide film formation rate increases and the dissolution rate of copper decreases, as a result the CMP removal rate of copper film decreases. With Benzotriazole(BTA) present in HNO3 based slurry, BTA passivated the copper surface from HNO3. And the copper removal is conducted by the abrasive polishing off the BTA from the copper surface then etching the copper surface by HNO3. In this study, we wish to investigate the concentration of oxidizer and inhibitor effect in acidic slurry system on the polishing mechanism of copper CMP. Electrochemical impedance-spectroscopy (EIS) measurements were applied in order to obtain a better fundamental understanding of the electrochemical reaction and the physical model of copper in the CMP process.