Abstract: A hermetically sealed housing for plural GaAs chips includes a body made from Al/SiC. The body defines a peripheral seal ring support surface, an electrical connector insert support surface and an end wall to which a ceramic insert is mounted. The insert includes a first portion with an upper surface within the sealed housing, Which upper surface is coplanar with the upper surface of the body, for convenient HDI film connections to the chips and electrical connector inserts. The refractory electrical conductors extend from the upper surface of the first portion of the insert to an exterior terminal portion of the insert. The terminal portion of the insert is spaced from the first portion of the insert by a non-terminal portion containing no terminals. The non-terminal portion of the insert is coplanar with the seal ring support surface of the body, and contiguous therewith.