Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy

Renjie Zhou, Chris Edwards, Amir Arbabi, Gabriel Popescu, Lynford L Goddard

Research output: Contribution to journalArticle


Due to the diffraction limited resolution and the presence of speckle noise, visible laser light is generally thought to be impractical for finding deep subwavelength defects in patterned semiconductor wafers. Here, we report on a nondestructive low-noise interferometric imaging method capable of detecting nanoscale defects within a wide field of view using visible light. The method uses a common-path laser interferometer and a combination of digital image processing techniques to produce 70 μm by 27 μm panoramic phase and amplitude images of the test nanopattern. Significant noise reduction and high sensitivity are achieved, which enables successful detection of several different types of sparse defects with sizes on the order of 20 nm wide by 100 nm long by 110 nm tall.

Original languageEnglish (US)
Pages (from-to)3716-3721
Number of pages6
JournalNano Letters
Issue number8
StatePublished - Aug 14 2013


  • defect inspection
  • Interferometric optical microscopy
  • metrology
  • nanotechnology
  • phase measurement

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

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