Design of lower stress and flexible CCGA solder joints and reliability expectancy

To improve the interconnect reliability of largedie area array package and reduce the stress concentration in solder joints under service load,the flexible interconnect structure for CCGA(ceramic column grid array) package and its solder joints shape are designed based on mechanics principle.Mechanical behaviors of the lower stress and flexible CCGA interconnect structure under shear load are studied by finite element method.Results showed that the designed copper taperedfunnel in both ends of copper column subjected to peak stress and peak strain of the interconnect structure,the weak solder and solder/Cu column interface away from the stress concentration location of the interconnect structure,stress and strain in solder joints decreased significantly comparing with the conventional CuCGA(ceramic copper column grid array) solder joints.So,higher interconnect reliability for large-die CCGA package can be expected due to the lower stress and flexible design.