Correlating Removal Rate to Directivity in Copper Chemical Mechanical Planarization
Gyu Kim, Sung
AffiliationUniv Arizona, Dept Chem & Environm Engn
MetadataShow full item record
PublisherELECTROCHEMICAL SOC INC
CitationMcAllister, J., Dadashazar, H., Sampurno, Y., Kim, S. G., Park, D., Kwon, H., ... & Philipossian, A. (2019). Correlating Removal Rate to Directivity in Copper Chemical Mechanical Planarization. ECS Journal of Solid State Science and Technology, 8(11), P734-P739.
Rights© 2019 The Electrochemical Society.
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AbstractThe relationship between directivity (Delta) and removal rate (RR) during copper chemical mechanical planarization (CMP) was investigated. We measured the high-frequency shear and normal forces generated by stick-slip (which has been routinely used to explain micro- and nano-scale interactions that lead to material removal), and found there to be a strong correlation between Delta (defined as the ratio of variances in shear force to those of normal force) and copper RR so long as the tribological mechanism remained constant. In cases where the tribological mechanism changed from "boundary lubrication" (BL) to "mixed lubrication" (ML), the slope of the straight-line correlation between Delta and RR was maintained, albeit it was shifted significantly lower. This was due to the ML regime consisting of hydrostatic or buoyant forces supporting the wafer, which led to less variability in frictional forces or less stick-slip events. Additionally, it was found that Delta and RR increased with sliding velocity while in BL due to an increase in stick-slip events. Conversely, Delta and RR decreased at lower sliding velocities while in ML due to an increase in hydrostatic or buoyant force supporting the wafer. (C) 2019 The Electrochemical Society.
VersionFinal accepted manuscript