Fracture origin of prismatic butt joints in relation to the intensity of singular stress field (ISSF)

Abstract

Adhesive joints are widely used in semiconductor packaging because of their light weight, low price, and high productivity. A recent study showed that the adhesive strength can be expressed as a constant value of the intensity of the singular stress field (ISSF) appearing at the interface end. However, since adhesive structures have complex three-dimensional geometries, it is necessary to find out where the debonding starts in relation to the ISSF to ensure product reliability. In this study, therefore, fundamental prismatic butt joint specimens are investigated considering the ISSF distribution along the interface circumference. It is found that most of the debonding starts from a point on the interface side except the interface corner where the peak ISSF appears in a limited region.