Texas Instruments Incorporated
PACKAGE SUBSTRATE WITH CTE MATCHING BARRIER RING AROUND MICROVIAS

Abstract:

A multi-layer package substrate includes a first build-up layer including a first dielectric layer and at least a second build-up layer including a second dielectric layer on the first build-up layer. The second build-up layer includes a top metal layer with a surface configured for attaching at least one integrated circuit (IC) die. The first build-up layer includes a bottom metal layer and a first microvia extending through the first dielectric layer, and the second build-up layer includes at least a second microvia extending through the second dielectric layer that is coupled to the first microvia. A barrier ring that has a coefficient of thermal expansion (CTE) matching material relative to a CTE of a metal of the second microvia positioned along only a portion of a height of at least the second microvia including at least around a top portion of the second microvia.