The Effect of Pad-asperity Curvature on Material Removal Rate in Chemical-mechanical Polishing
Name
Chun_The effect.pdf
Size
930.2 KB
Format
Adobe PDF
Checksum (MD5)
50b9c05b90972a348b5f3a2886073163
Author(s)
Kim, Sanha
Saka, Nannaji
Chun, Jung-Hoon
Date Issued
June 2014
Journal
Procedia CIRP
Publisher
Elsevier
Citation
Kim, Sanha, Nannaji Saka, and Jung-Hoon Chun. “The Effect of Pad-Asperity Curvature on Material Removal Rate in Chemical-Mechanical Polishing.” Procedia CIRP 14 (2014): 42–47.
Version
Final published version
Abstract
In chemical-mechanical polishing (CMP), surface asperities of the polishing pad play a key role, for they transmit normal force and impart tangential motion to the hard, nano-scale abrasive particles in the slurry. It has been shown recently, however, that the soft pad asperities themselves often generate micro-scale scratches on the surfaces being polished. To mitigate scratching by pad asperities, therefore, topography control by flattening pad asperities has been proposed and experimentally validated. In this study, the effects of asperity-flattening on pad topography and the material removal rate are investigated. It is found both theoretically and experimentally that even at a relatively high pressures only the tallest of the asperities are flattened and the ratio of asperity radius-to-standard deviation of heights is increased, but the average roughness itself is little affected. Specifically, surface profiles of new and asperity-flattened pads indeed show that the average roughness of about 5 μm is changed less than ten percent. Concurrently, the material removal rate is increased by about 30 percent due in part to the increased real area of contact––the result of increased asperity radius of curvature and decreased standard deviation of asperity heights.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Massachusetts Institute of Technology. Laboratory for Manufacturing and Productivity
Terms of Use
Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 Unported
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.procir.2014.03.014
