Integral heat sink with spiral manifolds

A heat sink (10) is provided for directly cooling at least one electronic device package (20) having an upper contact surface (22) and a lower contact surface (24). The heat sink comprises a cooling piece (16) formed of at least one thermally conductive material, where the cooling piece defines at least one inlet manifold (30) configured to receive a coolant and at least one outlet manifolds (32) configured to exhaust the coolant. The inlet and outlet manifolds are interleaved and are disposed in a spiral arrangement. The cooling piece further defines a number of millichannels (34) disposed in a radial arrangement and configured to receive the coolant from the inlet manifolds (30) and to deliver the coolant to the outlet manifolds (32). The millichannels (34) and inlet and outlet manifolds (30, 32) are further configured to directly cool one of the upper and lower contact surface (22, 24) of the electronic device package (20) by direct contact with the coolant, such that the heat sink (10) comprises an integral heat sink (10).