Development of B-spline X-ray Diffraction Imaging techniques for die warpage and stress monitoring inside fully encapsulated packaged chips

C. S. Wong*, A. Ivankovic, Nick Bennett, A. Cowley, A. N. Danilewsky, M. Gonzalez, V. Cherman, B. Vandevelde, I. De Wolf, P. J. McNally

*Corresponding author for this work

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

5 Citations (Scopus)


Advanced packaging is a key 'More than Moore' (MtM) enabling technology [1]. In all of these advanced packaging processes the semiconductor die are becoming much thinner (e.g. 25-50 μm thick) and many packages include multiply stacked silicon die. This leads to very thin packages where there is a trade-off between the thickness of constituent package layers and their rigidity, thus leading to reliability problems. Currently there are no compelling metrologies that can non-destructively measure the stress and/or warpage of the semiconductor die inside these packaged chips. Furthermore, since the thermal processing of these packages leads to the generation of thermal/mechanical stresses a new metrology, which is capable of real-time, or near real-time, monitoring of the generation or amelioration of these stresses during the thermal processing, would be a major advantage. In this study, we report on recent advances in the development of a new technique, which we describe as B-Spline X-Ray Diffraction Imaging (B-XRDI), which produces a reconstruction of strain field and/or lattice misorientation data from x-ray diffraction data/images of the in situ semiconductor die inside a test wirebonded encapsulated BGA package. High-speed digital x-ray topography images are captured at a synchrotron source (ANKA, Germany and Diamond, UK) in times as short as 8 seconds for a full 8 mm × 8 mm semiconductor die inside the fully encapsulated packages. Using a laboratory-based source (Jordan Valley Bede D1 High Resolution X-Ray Diffractometer) and applying the B-Spline technique, maps are also produced of the entire silicon die, which reveal warpage via measurements of x-ray rocking curve full-widths-at-half-maximum (FWHM) as a function of position across the encapsulated packages. These maps are also correlated with warpage measurements performed by mechanical and interferometric profilometry and finite element modelling (FEM).

Original languageEnglish
Title of host publication2014 IEEE 64th Electronic Components and Technology Conference (ECTC)
Number of pages6
ISBN (Print)9781479924073
Publication statusPublished - 2014
Event64th Electronic Components and Technology Conference 2014 - Orlando, United States
Duration: 27 May 201430 May 2014


Conference64th Electronic Components and Technology Conference 2014
Abbreviated titleECTC 2014
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials


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