A semiconductor package structure includes a substrate; and a die region having a plurality of dies disposed on the substrate. A first die of the plurality of dies is larger than a second die of the plurality of dies. The semiconductor package structure further includes a plurality of stress relief structures on the substrate. At least one stress relief structure of the plurality of stress relief structures is at a corner of the substrate. Each stress relief structure is spaced from a closest die of the plurality of dies by a first distance. Upper surfaces of each stress relief structure of the plurality of stress relief structures are unconnected.