HIGH-PERFORMANCE MULTI-CHIP IC PACKAGE

PROBLEM TO BE SOLVED: To provide a multi-chip IC package with high interconnection density. SOLUTION: The upper surface (or lower surface) of a flexible substrate is joined to a rigid support substrate with an opening for accommodating an IC chip that is joined to the upper surface (or lower surface) of the flexible substrate. In a preferred embodiment, a plurality of IC memories are mounted to one surface of the flexible substrate, and at least one logic chip is mounted to the other surface. An extremely thin flexible substrate is used to optimize the through hole interconnection length between the memory element and the logic element. When the logic chip is to be mounted to a hollow part that is formed by an opening by flip chips, a heat sink plate is used to cover the hollow part and at the same time perform efficient thermal contact to the reverse side of the logic chip.