Various embodiments of mechanisms for forming a die package and a package on package (PoP) structure using one or more compressive dielectric layers to reduce warpage are provided. The compressive dielectric layer(s) is part of a redistribution structure of the die package and its compressive stress reduces or eliminates bowing of the die package. In addition, the one or more compressive dielectric layers improve the adhesion between redistribution structure and the materials surrounding the semiconductor die. As a result, the yield and reliability of the die package and PoP structure using the die package are improved.