Use of urea-choline chloride eutectic solvent for back end of line cleaning applications

D. P.R. Thanu, S. Raghavan, M. Keswani

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


A liquid mixture formed from two benign chemicals, urea and choline chloride, in the molar ratio of 2:1 has been evaluated for post etch residue (PER) removal from copper surface. Residue films were prepared by etching DUV photoresist films coated on copper in CF4/O2 plasma. Film removal was evaluated under immersion cleaning conditions using X-ray photoelectron spectroscopy and scanning electron microscopy and verified using electrochemical impedance spectroscopy measurements. The residue film was effectively removed in the temperature range of 40-70C. The results of this study show that choline chloride and urea based DES system has the potential to function as a back end of line cleaning formulation.

Original languageEnglish (US)
Pages (from-to)H358-H361
JournalElectrochemical and Solid-State Letters
Issue number9
StatePublished - 2011
Externally publishedYes

ASJC Scopus subject areas

  • General Chemical Engineering
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Electrochemistry
  • Electrical and Electronic Engineering


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