Precise assessment of thermal deformation in microelectronic packaging interconnect bumps using an adaptive rigid body motion elimination method

Abstract The miniaturization of microelectronic packaging brings complex reliability challenges, with corner bumps being particularly failure-prone. Precise measurement of thermal deformation failure behavior of these micro regions is critical. However, the actual deformation is hindered by rigid body motion caused by thermal mismatch-induced package warpage, which varies for each bump and may displace them from the field of view during temperature changes. In this study, a deformation evaluation method combined adaptive rigid body motion eliminating with digital image correlation is developed, which is based on the characteristics of each interconnect bump. The method uses local feature recognition and matching to address rigid body rotation and these features are identified by an algorithm that has been developed. Through reasonable assumptions, the rotation angle is obtained by fitting the identified features to eliminate the rigid body rotation, and eliminating rigid body translation through displacement transformation. The verification experiment indicates that the proposed method is validated, achieving an average error below 0.72%. Furthermore, the displacement and strain field evolution behavior of corner bumps were analyzed under a temperature cycle from −40 °C to 150 °C. Obtained experimental results indicate that the most fatigue-prone area is located at the inner interface between the chip and the bump, while the most tensile-stress-prone area is at the outer interface between the bump and the substrate. This study provides an effective approach to eliminate rigid body motion and offers valuable insights into the failure-prone regions of corner bumps, contributing to the reliability analysis of microelectronics packaging.