a method and structure for reducing thermally induced strains on the solder joints that couple a ball grid array module to a circuit card , so as to improve the fatigue life of the bga module . the thermally induced strains arise from a mismatch in thermal expansion coefficient between the dielectric substrate of the bga module and the dielectric board of the circuit card . the method generates void annular regions around portions of the bga dielectric substrate to which the bga solder balls are to be attached and / or around portions of the circuit card dielectric material to which the bga module is to be attached . this results in the formation of dielectric islands or peninsulas that bound the solder balls of the bga module after installation on the circuit card . the dielectric islands or peninsulas thus formed serve to increase the effective height over which the differential expansion is accommodated , thereby reducing the strains throughout the solder joints . additionally , the void annular regions provide space for the deformation of the dielectric islands or peninsulas , thereby increasing their compliance and transferring strain from the solder joints to the dielectric islands or peninsulas .