TY - JOUR
T1 - Comparison of copper disc and copper wafer polishing processes in terms of their kinetic, tribological, and thermal characteristics
AU - Li, Zhonglin
AU - Lefevre, Paul
AU - Koshiyama, Isamu
AU - Ina, Katsuyoshi
AU - Boning, Duane
AU - Philipossian, Ara
N1 - Funding Information:
Manuscript received October 27, 2003. This work was supported in part by the National Science Foundation/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing. Z. Li and A. Philipossian are with the Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721 USA. P. Lefevre is with Fujimi Corporation, Tualatin, OR 97070 USA. I. Koshiyama and K. Ina are with Fujimi Incorporated, Kagamigahara, Gifu 509-0108, Japan. D. Boning is with the Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139 USA. Digital Object Identifier 10.1109/TSM.2005.858522
PY - 2005/11
Y1 - 2005/11
N2 - Coefficients of friction, removal rate, and pad temperature analysis were used to compare chemical-mechanical polishing processes involving two substrates, copper discs and copper-deposited wafers with different grain sizes and degrees of flatness (i.e., concave or convex). The average coefficient of friction and the total mechanical energy of the processes (as measured by the spectral attributes of the raw frictional force) were higher for the copper-deposited wafers. This result is believed to be due to differences in the extent of convexity of the two types of substrates and the shapes of their bevels. Pad temperature transients as well as material removal rates were also slightly higher for the copper wafers, suggesting a thermally dependent removal mechanism. Grain sizes associated with the copper-deposited wafers used in this paper were larger compared to those of the copper discs. Grains are thought to have complex interactions with the chemical as well as mechanical attributes of the process, based on the fact that smaller grains led to greater chemical reaction rates, while they needed more mechanical force to abrade away. Based on these results, careful attention to copper grain size as well as deposited film and wafer geometry is recommended in experimental studies of copper polishing.
AB - Coefficients of friction, removal rate, and pad temperature analysis were used to compare chemical-mechanical polishing processes involving two substrates, copper discs and copper-deposited wafers with different grain sizes and degrees of flatness (i.e., concave or convex). The average coefficient of friction and the total mechanical energy of the processes (as measured by the spectral attributes of the raw frictional force) were higher for the copper-deposited wafers. This result is believed to be due to differences in the extent of convexity of the two types of substrates and the shapes of their bevels. Pad temperature transients as well as material removal rates were also slightly higher for the copper wafers, suggesting a thermally dependent removal mechanism. Grain sizes associated with the copper-deposited wafers used in this paper were larger compared to those of the copper discs. Grains are thought to have complex interactions with the chemical as well as mechanical attributes of the process, based on the fact that smaller grains led to greater chemical reaction rates, while they needed more mechanical force to abrade away. Based on these results, careful attention to copper grain size as well as deposited film and wafer geometry is recommended in experimental studies of copper polishing.
KW - Coefficient of friction
KW - Cu chemical-mechanical planarization (CMP)
KW - Material removal
KW - Physical properties of the substrate
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U2 - 10.1109/TSM.2005.858522
DO - 10.1109/TSM.2005.858522
M3 - Article
AN - SCOPUS:28644443215
SN - 0894-6507
VL - 18
SP - 681
EP - 686
JO - IEEE Transactions on Semiconductor Manufacturing
JF - IEEE Transactions on Semiconductor Manufacturing
IS - 4
ER -