Infusing Inorganics into the Subsurface of Polymer Redistribution Layer Dielectrics for Improved Adhesion to Metals Interconnects

This paper demonstrates a new class of inorganic-organic hybrid dielectric materials to address the requirements for high-temperature reliability of next-generation high-density, high-power packages and electronics in harsh environments for automotive applications. A major concern for reliability is the inadequate adhesion of metals with high-temperature polymers. Adhesion deteriorates further via thermal and oxidative exposure and moisture absorption. In this paper, a novel vapor phase infiltration (VPI) technique is applied to create an organic-inorganic hybrid dielectric surface that improves metal-polymer adhesion. The VPI process infuses inorganic constituents to a depth of at least 3 microns, as revealed by elemental analysis using SEM-EDX and XPS depth profiles. In preliminary testing, Cu/Cr films deposited onto these modified polymer surfaces exhibit 3x higher peel strength than metal films deposited on untreated polymer.