Image-based overlay and alignment metrology through optically opaque media with sub-surface probe microscopy

Maarten H. van Es, Abbas Mohtashami, Daniele Piras, Hamed Sadeghian

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

5 Citations (Scopus)
1 Downloads (Pure)

Abstract

Nondestructive subsurface nanoimaging through optically opaque media is considered to be extremely challenging and is essential for several semiconductor metrology applications including overlay and alignment and buried void and defect characterization. The current key challenge in overlay and alignment is the measurement of targets that are covered by optically opaque layers. Moreover, with the device dimensions moving to the smaller nodes and the issue of the so-called loading effect causing offsets between between targets and product features, it is increasingly desirable to perform alignment and overlay on product features or so-called on-cell overlay, which requires higher lateral resolution than optical methods can provide. Our recently developed technique known as SubSurface Ultrasonic Resonance Force Microscopy (SSURFM) has shown the capability for high-resolution imaging of structures below a surface based on (visco-)elasticity of the constituent materials and as such is a promising technique to perform overlay and alignment with high resolution in upcoming production nodes. In this paper, we describe the developed SSURFM technique and the experimental results on imaging buried features through various layers and the ability to detect objects with resolution below 10 nm. In summary, the experimental results show that the SSURFM is a potential solution for on-cell overlay and alignment as well as detecting buried defects or voids and generally metrology through optically opaque layers.

Original languageEnglish
Title of host publicationMetrology, Inspection, and Process Control for Microlithography XXXII
Place of PublicationBellingham
PublisherSPIE
Number of pages8
ISBN (Electronic)9781510616622
DOIs
Publication statusPublished - 1 Jan 2018
EventMetrology, Inspection, and Process Control for Microlithography XXXII - San Jose, United States
Duration: 26 Feb 20181 Mar 2018

Publication series

NameProceedings of SPIE
Volume10585

Conference

ConferenceMetrology, Inspection, and Process Control for Microlithography XXXII
CountryUnited States
CitySan Jose
Period26/02/181/03/18

Keywords

  • defects
  • on-cell
  • overlay and alignment
  • Scanning probe microscopy

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