Thermomechanical strain measurements by synchrotron x-ray diffraction and data interpretation for through-silicon vias

Abstract

To study thermomechanical strain induced by the mismatch of coefficients of thermal expansion in through-silicon vias (TSVs) and thus provide fundamental understanding of TSV reliability, strain measurements have been performed with synchrotron x-ray diffraction (XRD). The measured strains are available as two-dimensional (2D) distribution maps, whereas the strain distributions in TSVs are three-dimensional (3D) in nature. To understand this 3D to 2D data projection process, a data interpretation method based on beam intensity averaging is proposed and validated with measurements. The proposed method is applicable to XRD strain measurements on thin as well as thick samples.