Abstract: Embodiments include systems in packages (SiPs) and a method of forming the SiPs. A SiP includes a package substrate and a first modularized sub-package over the package substrate, where the first modularized sub-package includes a plurality of electrical components, a first mold layer, and a redistribution layer. The SiP also includes a stack of dies over the package substrate, where the first modularized sub-package is disposed between the stack of dies. The SiP further includes a plurality of interconnects coupled to the stack of dies, the first modularized sub-package, and the package substrate, wherein the redistribution layer of the first modularized sub-package couples the stack of dies to the package substrate with the plurality of interconnects. The SiP may enable the redistribution layer of the first modularized sub-package to couple the electrical components to the stacked dies and the package substrate without a solder interconnect.