A semiconductor package includes a substrate having one or more dice mounted thereto, and a cover adapted to protect and form a sealed space for the dice. The cover can be pre-fabricated of molded plastic, or stamped metal, and attached to the substrate using a cured seal. A hole can also be provided through the substrate to permit pressure equalization during formation of the seal. The cover can be prefabricated in an enclosed configuration for attachment directly to the substrate, or in a planar configuration for attachment to a peripheral ridge on the substrate. In either embodiment, the cover is removable to permit defective dice to be replaced or repaired.