Patent ID: 7094975

Claim:
A circuit board assembly comprising a laminate organic substrate having oppositely-disposed first and second surfaces, a surface-mount device attached with a plurality of solder bumps to the first surface of the laminate organic substrate, and a localized stiffener attached with a pluralitv of solder bumps to the second surface of the laminate organic substrate directly opposite the device wherein the solder bumps space the localized stiffener from the laminate organic substrate to define a gap therebetween, the device and the localized stiffener having lateral dimensions in a plane parallel to the first and second surfaces of the laminate organic substrate with at least one of the lateral dimensions of the localized stiffener being greater than the lateral dimensions of the device, the laminate organic substrate, the device, and the localized stiffener having coefficients of thermal expansion and having moduli of elasticity, the coefficients of thermal expansion of the device and the localized stiffener being less than the coefficient of thermal expansion of the laminate organic substrate, the modulus of elasticity of the localized stiffener being greater than the modulus of elasticity of the laminate organic substrate, the localized stiffener being attached to the laminate organic substrate so as to locally stiffen the laminate organic substrate beneath the device and thereby increase the fatigue life of the at least one solder bump.