Alignment mark detection in CMOS materials with SCALPEL e-beam lithography

Reginald C. Farrow, Warren K. Waskiewicz, Isik Kizilyalli, Gregg Gallatin, J. Alexander Liddle, Masis Mkrtchyan, Avi Kornblit, Leonidas Ocola, Fred Klemens, Joseph A. Felker, Christopher Biddick, Joseph S. Kraus, Myrtle Blakey, Paul Orphanos, Nace Layadi, Sailesh Merchant

Research output: Contribution to journalConference articlepeer-review


A manufacturable process for fabricating alignment marks that are compatible the SCALPEL lithography system is described. The marks were fabricated in a SiO2/WSi2 structure using SCALPEL lithography and plasma processing. The positions of the marks were detected through e-beam resist in the SCALPEL proof of lithography (SPOL) tool by scanning the image of the corresponding mask mark over the wafer mark and detecting the backscattered electron (BSE) signal. Scans of 1 μm line-space patterns yielded mark positions that were repeatable within 20 nm 3σ with a dose of 4 μC/cm2 and signal-to-noise of 32 dB. An analysis shows that the measured repeatability is consistent with a random noise limited response combined with SPOL machine factors. By using a digitally sequenced mark pattern, the capture range of the mark detection was increased to 13 μm while maintaining 36 nm 3σ precision. Further improvements in mark detection repeatability are expected when the SCALPEL electron optics is fully optimized.

Original languageEnglish (US)
Pages (from-to)217-226
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Issue numberI
StatePublished - 1999
Externally publishedYes
EventProceedings of the 1999 Emerging Lithographic Technologies III - Santa Clara, CA, USA
Duration: Mar 15 1999Mar 17 1999

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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