Patent ID: 7859846

Claim:
A power module assembly with low thermal resistance, comprising: a heat sink plate with a lower surface and an upper surface, the heat sink plate comprising a plurality of passageways for coolant extending from the lower surface to the upper surface; a circuit substrate positioned on the heat sink plate covering the coolant passageways, wherein the heat sink plate further comprises a recessed surface on the upper surface extending continuously about the periphery of one or more of the coolant passageways; a sealing member positioned in the recessed surface of the heat sink plate, the sealing member comprising a compressible material; and a set of power modules mounted on the circuit substrate opposite a bonding layer, wherein each of the coolant passageways has a circular cross section with a sidewall extending from the lower surface to the upper surface of the heat sink plate, and wherein the sidewalls slope inward from the lower surface such that each of the coolant passageways has a diameter at the lower surface that is greater than a diameter at the upper surface of the heat sink plate.