A comparison of X-ray microdiffraction and coherent gradient sensing in measuring discontinuous curvatures in thin film: Substrate systems

Michal A. Brown*, Tae Soon Park, Ares Rosakis, Ersan Ustundag, Young Huang, Nobumichi Tamura, Bryan Valek

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The coherent gradient sensor (CGS) is a shearing interferometer which has been proposed for the rapid, full-field measurement of deformation states (slopes and curvatures) in thin film-wafer substrate systems, and for the subsequent inference of stresses in the thin films. This approach needs to be verified using a more well-established but time-consuming grain orientation and stress measurement tool. X-ray microdiffraction (XRD). Both CGS and XRD are used to measure the deformation state of the same W film/Si wafer at room temperature. CGS provides a global, wafer-level measurement of slopes while XRD provides a local micromeasurement of lattice rotations. An extreme case of a circular Si wafer with a circular W film island in its center is used because of the presence of discontinuous system curvatures across the wafer. The results are also compared with a theoretical model based on elastic plate analysis of the axisymmetric biomaterial film-substrate system. Slope and curvature measurements by XRD and by CGS compare very well with each other and with theory. The favorable comparison demonstrates that wafer-level CGS metrology provides a quick and accurate alternative to other measurements. It also demonstrates the accuracy of plate theory in modeling thin film-substrate systems, even in the presence of curvature discontinuities.

Original languageEnglish (US)
Pages (from-to)723-729
Number of pages7
JournalJournal of Applied Mechanics, Transactions ASME
Volume73
Issue number5
DOIs
StatePublished - Sep 1 2006

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'A comparison of X-ray microdiffraction and coherent gradient sensing in measuring discontinuous curvatures in thin film: Substrate systems'. Together they form a unique fingerprint.

  • Cite this