Wafer defect detection by a polarization-insensitive external differential interference contrast module

Amit Nativ, Haim Feldman, Natan T. Shaked*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present a system that is based on a new external, polarization-insensitive differential interference contrast (DIC) module specifically adapted for detecting defects in semiconductor wafers. We obtained defect signal enhancement relative to the surrounding wafer pattern when compared with bright-field imaging. The new DIC module proposed is based on a shearing interferometer that connects externally at the output port of an optical microscope and enables imaging thin samples, such as wafer defects. This module does not require polarization optics (such as Wollaston or Nomarski prisms) and is insensitive to polarization, unlike traditional DIC techniques. In addition, it provides full control of the DIC shear and orientation, which allows obtaining a differential phase image directly on the camera (with no further digital processing) while enhancing defect detection capabilities, even if the size of the defect is smaller than the resolution limit.

the potential of future integration into semiconductor production lines.

Original languageEnglish
Pages (from-to)3534-3538
Number of pages5
JournalApplied Optics
Volume57
Issue number13
DOIs
StatePublished - 1 May 2018

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