An apparatus for clock skew compensation is provided. The apparatus includes a first delay locked loop (DLL) module disposed in a first die and a second DLL module disposed in a second die. A first input terminal of the first DLL module receives a reference clock. A first input terminal of the second DLL module is electrically connected to an output terminal of the first DLL module. An output terminal of the second DLL module is electrically connected to a second input terminal of the first DLL module.