Semiconductor Device and Method Forming Same

Package structures and methods of forming package structures are discussed. A package structure, in accordance with some embodiments, includes a large package component, such as a CoWoS, adhered to a large package substrate, such as a printed circuit board, an underfill material disposed between the large package component and the large package substrate, and a stress-release structure with high elongation values formed from photolithography encapsulated by the underfill material. The stress-release structure helping to reduce stress in the underfill material to reduce the risk of underfill cracking caused by the difference in coefficients of thermal expansion between the large package component and the large package substrate.