Physical, chemical, and in vitro toxicological characterization of nanoparticles in chemical mechanical planarization suspensions used in the semiconductor industry: Towards environmental health and safety assessments

David Speed, Paul Westerhoff, Reyes Sierra-Alvarez, Rockford Draper, Paul Pantano, Shyam Aravamudhan, Kai Loon Chen, Kiril Hristovski, Pierre Herckes, Xiangyu Bi, Yu Yang, Chao Zeng, Lila Otero-Gonzalez, Carole Mikoryak, Blake A. Wilson, Karshak Kosaraju, Mubin Tarannum, Steven Crawford, Peng Yi, Xitong LiuS. V. Babu, Mansour Moinpour, James Ranville, Manuel Montano, Charlie Corredor, Jonathan Posner, Farhang Shadman

Research output: Contribution to journalReview article

37 Scopus citations

Abstract

This tutorial review focuses on aqueous slurries of dispersed engineered nanoparticles (ENPs) used in chemical mechanical planarization (CMP) for polishing wafers during manufacturing of semiconductors. A research consortium was assembled to procure and conduct physical, chemical, and in vitro toxicity characterization of four ENPs used in CMP. Based on input from experts in semiconductor manufacturing, slurries containing fumed silica (f-SiO2), colloidal silica (c-SiO2), ceria (CeO2), and alumina (Al2O3) were selected and subsequently obtained from a commercial CMP vendor to represent realistic ENPs in simplified CMP fluids absent of proprietary stabilizers, oxidants, or other chemical additives that are known to be toxic. ENPs were stable in suspension for months, had highly positive or negative zeta potentials at their slurry working pH, and had mean diameters measured by dynamic light scattering (DLS) of 46 ± 1 nm for c-SiO2, 148 ± 5 nm for f-SiO2, 132 ± 1 nm for CeO2, and 129 ± 2 nm for Al2O3, all of which were larger than the sub 100 nm diameter primary particle sizes measured by electron microscopy. The concentration of ENPs in all four slurries that caused 50% inhibition (IC-50) was greater than 1 mg mL-1 based on in vitro assays using bioluminescence of the bacterium Aliivibrio fischeri and the proliferation, viability, and integrity of human cells (adenocarcinomic human alveolar basal epithelial cell line A549). The general practice in the CMP industry is to dilute the slurry waste stream so actual abrasive concentrations are typically orders of magnitude smaller than 1 mg mL-1, which is lower than IC-50 levels. In contrast to recent reports, we observed similar toxicological characteristics between c-SiO2 and f-SiO2, and the materials exhibited similar X-ray diffraction (XRD) spectra but different morphology observed using electron microscopy. The ENPs and CMP slurries used in this study have been made available to a number of other research groups, and it is the intention of the consortium for this paper to provide a basis for characterizing and understanding human and environmental exposures for this important class of industrial ENPs. This journal is

Original languageEnglish (US)
Pages (from-to)227-244
Number of pages18
JournalEnvironmental Science: Nano
Volume2
Issue number3
DOIs
StatePublished - Jun 1 2015

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Environmental Science(all)

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    Speed, D., Westerhoff, P., Sierra-Alvarez, R., Draper, R., Pantano, P., Aravamudhan, S., Chen, K. L., Hristovski, K., Herckes, P., Bi, X., Yang, Y., Zeng, C., Otero-Gonzalez, L., Mikoryak, C., Wilson, B. A., Kosaraju, K., Tarannum, M., Crawford, S., Yi, P., ... Shadman, F. (2015). Physical, chemical, and in vitro toxicological characterization of nanoparticles in chemical mechanical planarization suspensions used in the semiconductor industry: Towards environmental health and safety assessments. Environmental Science: Nano, 2(3), 227-244. https://doi.org/10.1039/c5en00046g