Transfer molding of integrated circuit packages

A method, mold and apparatus for encapsulating and underfilling an integrated circuit chip assembly. The mold has a first portion and a second portion with the first portion having first and second cavities and at least one channel interconnecting said first and second cavities. The first cavity is adapted to enclose said integrated circuit chip on said substrate. A clamping force is applied to the first and second portions of the mold to clamp the substrate between them with the integrated circuit chip located in the first cavity. Vents exhaust air from the first cavity. Encapsulant is injected into the first cavity of the first portion at a location in the first portion remote from the point of connection of the channel such that encapsulant flows around and underneath the integrated circuit chip and through the channel into the second cavity to thereby underfill and encapsulate the integrated circuit assembly.