US Patent 7361972 Chip packaging structure for improving reliability

A novel chip packaging structure is disclosed. The chip packaging structure includes a flip chip having a chip backside, at least one concave stress-relieving structure provided in the chip backside, a carrier substrate bonded to the flip chip and an adhesive material interposed between the flip chip and the carrier substrate. During thermal testing and/or functioning of the flip chip, the stress-relieving structure reduces stresses between the flip chip and the carrier substrate and dissipates heat from the flip chip to reduce thermally-induced delamination stresses applied to the adhesive material and thereby enhances reliability of the flip chip.