Abstract: Multi-chip modules and methods to form multi-chip modules are disclosed. A disclosed method to form a multi-chip module includes attaching a first integrated circuit to a top surface of a substrate, attaching a second integrated circuit to the top surface of the substrate, the top surface of the second integrated circuit having a top surface taller than a top surface of the first integrated circuit, and attaching a heat conductor to the top surface of the first and second integrated circuits.

Abstract: Methods for preparing thermally enhanced multilayer substrates and methods for their use in assembling BGA packages are disclosed. Steps in preferred embodiments of the invention include opening a hole in a dielectric material at one surface of a multilayer substrate thereby forming a die pad on the second metal layer or primary thermal spreading layer. A plurality of vias are provided through the substrate from the surface of the die pad to the opposing surface of the substrate. In an alternative embodiments of the invention, an embedded thermal conductor is also formed on the die pad. In another embodiment, a hole in an bottom dielectric layer exposing a bottom metal layer and embedded thermal conductor may also be provided between the bottom of the substrate and the second metal layer from the bottom, e.g. the third and fourth layers. The die pad may be plated, cleaned, and/or masked to receive a die.