A photo‐elastic microscopy study of the temperature dependency of stress induced by through silicon vias in silicon

Abstract

SIREX (Scanning Infrared Stress Explorer) is a photo‐elastic microscope in this case applied to characterize the temperature dependence of stress induced by copper Through Silicon Via (TSV) structures in silicon. The temperature was varied between 285 and 320 K. SIREX provides images of the lateral distribution of Δσ being the difference of the in‐plane principal stress components. The single TSV as well as the TSV group are considered as point‐like stress sources. The related single radial profiles of Δσ are quantitatively analysed. It is confirmed that the profiles at large distance from the TSV can be described by Lamé's law (Δσ ∼ R‐m, m ≈ 2) modified by a term of temperature dependency. The stress decreases linearly with temperature. These experiments allow for estimating the zero stress temperature.