An apparatus and method for creating a metallic thermal interface is shown for connecting an electronic module to a heat sink. Using an interface metal such as indium or malleable indium alloys, which have superior heat transfer capability, but are subject to oxidization and degraded thermal transfer capability; a layer of interface material is confined in a recess in the heat sink base into which the module cap is received. The thermal interface region is then evacuated to bring the module top surface and recess major surface into intimate contact and sealed along the interface of the module and recess side walls to exclude air from the metallic interface region.