Copper interconnects and low k dielectrics have been introduced in advanced IC technology to reduce the interconnect resistance, improve the resistance to electromigration and reduce RC delay and cross talk effects. The introduction of new materials in integrated circuits makes the root cause determination and correction action implementation more challenging. Moreover, the complexity of package structure generates additional impact on degrading the yield of assembly processing manufacture. This main purpose of this study is to investigate the influence of introducing Cu-/Low K wafer phase on actual manufacturing situation. Issues related to the failures of assembly process were analyzed for determining the root cause, in which such as die chipping issue during die sawing process, bond pad peeling/crater issues during wire bonding process and die crack / delamination issues after pre-condition and reliability test. The DOE/JMP methodology was used to achieve the optimium assembly processing condition so as to improve the quality of products, and then the mass production with stable yield could be realized.