Metrology of Silicon Wafers through Synchrotron Section Topography and X-ray Diffraction Imaging

X-ray metrology, a non-destructive characterization technique, was used to evaluate the warpage induced in a Silicon wafer on substrate with predefined warpage. Section topography images were recorded at Synchrotron radiation source and were validated using a lab-based X-ray diffraction imaging system. Topography images and line scans were collected from the entire wafer at multiple 90-degree rotations. The topography images were processed using our new custom-built image-processing user-interface called MasqueTron to extract the angular offset data. The angular offset data and FWHM data were also collected through line-scans using the lab-based technique. All these data were the input of a methodology to produce 3D maps of the warpage and surface dislocations. The lab-based results are compelling to synchrotron topography data and agree well with the optical profilometry reported in literature. The technique has potential to be developed further to image the warpage and cracks induced in Silicon wafer inside the packaged chips under thermo-mechanical stress which is imposed to the wafer during fabrication and encapsulation during manufacturing process. The lab-based imaging techniques require further development to automat imaging the warpage of the entire wafer and to reduce the scanning time from days and hours to seconds as can be done at synchrotron radiation source. The warpage of the wafer calculated to be 3 μm and convex shape.