Critical dimension AFM tip characterization and image reconstruction applied to the 45 nm node

Gregory Dahlen, Marc Osborn, Bernard Haochih Liu, Rohit Jain, William Foreman, Jason R. Osborne

Research output: Chapter in Book/Report/Conference proceedingConference contribution

25 Citations (Scopus)


Three significant critical dimension atomic force microscopy (CD AFM) advances are presented in this paper. First, scanning probe image reconstruction methodologies that were formerly limited to parabolic type tip shapes and single-valued surfaces (i.e., non-reentrant topography), are extended to multi- valued surfaces and reentrant tip geometries. This crucial step allows the elimination of image artifacts associated with CD AFM scanning of complex feature shapes using reentrant tips. Second, in situ AFM tip images are provided in an automated tool that enables full image reconstruction. Consequently, for the first time, the combination of in situ tip reconstruction with the inherent reference measurement qualities of the AFM and full morphology reconstruction allow CD AFM metrology essentially free of tip shape effects. As a result, CD AFM is now primarily driven by development of tip geometries that contact the entire specimen surface while retaining adequate tip lifetime. In order to explain the importance of the present development in eliminating measurement bias, the background of CD AFM image dilation is described in detail, and the limitations of "legacy" ID image reconstruction is examined. Initial validation of the automated software is provided by comparison with TEM micrographs. Tip characterizations are presented for a morphologically complex ∼20 nm diameter carbon nanotube tip and reentrant silicon CD32 tips (tip width ∼ 30nm). Finally, the capability for CD AFM to scan a reentrant sub-45 nm width trench is demonstrated. An EUV resist trench was scanned with a CD32 tip (tip width = 27.4 nm). Minimum CD ranged from 42 to 45 nm. Reentrant image reconstruction is shown for the scan cross-section.

Original languageEnglish
Title of host publicationMetrology, Inspection, and Process Control for Microlithography XX
Publication statusPublished - 2006 Jul 10
EventMetrology, Inspection, and Process Control for Microlithography XX - San Jose, CA, United States
Duration: 2006 Jan 202006 Jan 23

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6152 II
ISSN (Print)0277-786X


OtherMetrology, Inspection, and Process Control for Microlithography XX
CountryUnited States
CitySan Jose, CA

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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