A next generation non etching adhesion promoter enabling streamlined process for Advanced IC substrates

As IC substrate technology advances towards fine lines and higher circuit densities, there is an increasing demand for copper (Cu) surface preparation to ensure reliable adhesion with lamination materials and resistance to external stress conditions. At the same time, it is essential to ensure process efficiency and support signal integrity. Conventional approaches often rely on multi-step roughening techniques to maintain adhesion in the presence of thermal, humid and chemical stresses between Cu and the dielectric. However, these techniques compromise the integrity of the Cu surface and are incompatible with the requirement for ultra-smooth conductors.This study presents an innovative, self-synthesized, organo-silane-based adhesion promoter designed to form strong chemical bonds between dissimilar materials such as various dielectric laminates and Cu surfaces (including electrolytically plated Cu). Unlike traditional roughening-based systems, our non-etch solution enables a streamlined two-step process that simplifies manufacturing, reduces costs, and maintains the high bond strength required for next-generation packaging, eliminating the need for aggressive copper etching, our non-etch solution allows for the creation of narrower lines and spaces, which are essential for advanced IC substrate designs.The system also demonstrates excellent chemical resistance to desmear process, which is necessary to clean blind microvias (BMVs) after laser drilling and prepare them for subsequent Cu filling. Smooth Cu surfaces typically struggle in these harsh conditions, but post-desmear testing of structured designs confirmed the integrity of the sidewalls and minimal wedge formation at the BMV interfaces. Roughness measurements show that our process does not alter the original surface topography. Extended IR Reflow and high-temperature accelerated stress testing (HAST) provide further validation of the durability of the interface. The effectiveness of the promoter in maintaining strong Cu-dielectric bonding under harsh stress conditions is demonstrated by FESEM and FIB analysis.As a global leader in laser, desmear chemistry and surface treatment, our understanding of interfacial processes extends beyond adhesion alone. This allows us to support customers with fully integrated bonding solutions, combining advanced materials, process integration and application expertise to meet the evolving demands of IC substrate manufacturing.