Resistance to warpage deformation of area array packaging interconnect under thermal cyclic load

The warpage behaviors of solder ball array interconnect, solder column array interconnect and copper column array interconnect structures under thermal cycling load were studied by finite element software. The results show that the warpage deformations of three kinds of area array interconnects is the same, the resin substrates with low stiffness exhibit a concave deformations during the heating stage above room temperature, while the convex deformation occurs after cooling to 0 °C. The stress and torque in the substrates and the ball /column array interconnects caused by the difference of thermal expansion coefficients of both ends substrates at different temperatures are the driving forces of warping. The resin substrates of the solder/copper column array interconnect have similar warpage displacements, but both of them are obviously lower than the substrates of solder ball array interconnect, and the warpage deformation resistance is higher. Under the thermal cycling temperature range from –40 °C to 125 °C and given substrate size condition, the yielding deformation of the copper column has not occurred. Comparison with the solder column array interconnect, the advantage of releasing stress by flexural deformation of the copper column is not exhibit.