Characterizations and Challenges of Adhesion Promotion Solutions for HSIO Package Development

The demand for higher performance is driving package transmission lines to operate at higher frequencies with lower package insertion loss budgets. A typical solution to create adhesion between the copper and dielectric is by roughening the copper surface to provide anchors on which the laminated dielectric adheres. However, the requirements for next generation of high-speed input/output (HSIO) drives the need for lower roughness copper surface. A non-roughened solution, therefore, using chemical adhesive layer to enable a smoother copper-dielectric interface without compromising this metal-organic interfacial adhesion is required. In this work, we develop a series of characterization methods to understand the structure-property relationship of an organic adhesive film as example, which give significant insights to guide the materials/chemical screening processes to facilitate the development cycle. It is also demonstrated that the corrosion protection offered by the adhesive films plays a key role on improving interfacial integrity and reliability of next generation interconnects.