Electro-thermo-mechanical behavior and reliability of anisotropic conductive polymer adhesives for electronic packaging applications

Abstract

In this study, electro-thermo-mechanical responses of anisotropic conductive adhesive materials and assembly reliability were investigated. A number of studies have turned their attention to the development of contact models for understanding the ACA interconnects. Chapter Two introduces an experimental technique developed to allow continuous monitoring of deformation characteristics of a single conductive particle. The load-deformation curve of single conductive particle is accurately measured, which provide (1) the accurate force vs. deformation relation of single conductive particle, (2) elastic recovery characteristics, and (3) basic information for the deformation of multi-particles system on bumps. Based on the deformation behaviors of each conductive particle, mechanical and electrical properties of ACA joint were discussed to improve the bonding quality and reliability. Chapter Three presents the thermal and mechanical contribution of anisotropic conductive films (ACFs) to the electrical conduction establishment of ACF joint. In this part, ACF flip chip process is fully designed based on the material characterization and in-situ process monitoring. Moreover, the effect of degree of cure on the ACF conduction establishment is investigated in a bonding process window. The build-up shrinkage stress for the conduction establishment is experimentally considered with thermo-mechanical measurement of ACF. Chapter Four discusses the importance of the mechanism of shrinkage and contraction stress and the relationship between these mechanisms and the thermo-mechanical properties of ACFs. Both thickness shrinkages and modulus changes of four kinds of ACFs with different thermo-mechanical properties are experimentally investigated with thermo-mechanical and dynamic mechanical analysis. Based on the incremental approach to linear elasticity, contraction stresses of ACFs developed along the thickness direction are estimated. In this contribution, we establish a metho...