Analysis On The Thermal Fracture Mechanic In Packaging Structure With Interface

Packaging structure plays an important role in the current development of electronic components. With the rapid development of modern electric technology, electronic machines are becoming smaller and lighter with higher reliability and lower cost. While the restrictions to electronic systems with high performance and further miniaturization is not due to the component itself, but due to its assembly and packaging methods. Thermal fracture is the major failure model of packaging materials. It absorbed great attention from the international research community. The study of the thermal fracture problems of package structures with interfaces is very important for the structure of the designment, optimization and reliable application of package structures. In this paper,the thermal fracture behavior of the packaging structure with crack is studied by interaction integral combined with numerical method. In Chapter One, the advance of packaging structure is reviewed, since packaging structure belongs to nonhomogeneous material, the recent development of fracture mechanics of nonhomogeneous materials is also reviewed.In Chapter Two, the method on how to derive the temperature field and thermal stress fields is given in order to obtain the thermal stress intensity factors (TSIFs) of packaging structure. Then, the extended finite element method (XFEM) is introduced.In Chapter Three, the modified J-integral and interaction integral with path-independence are given for nonhomogeneous materials with interface subject to thermal loading. At last, the method of how to get the stress intensity factors (SIFs) from interaction integral is given.In Chapter Four, some numerical examples are checked to verify the present method. Then, the TSIFs of the nonhomogeneous materials with a weak interface are computed. The effects of elastic modules, thermal conductivity and other parameters on TSIFs are analyzed.In Chapter Five, several simplified models of packaging structures are established. Using the above method, the TSIFs are evaluated and the influences of the crack length, temperature and the location of the crack on TSIF are considered.