Cointegration of Single-Mode Waveguides and Embedded Electrical Interconnects for High-Bandwidth Communications

This article presents the modeling, development, and demonstration of glass interposer technology with single-mode waveguides (SMWGs) for high-bandwidth communications and embedded trenches for ultrafine copper traces for high-speed electronics. Glass as the substrate for the integration of photonics and electronics exhibits a unique combination of superior properties over silicon, laminates, and polymers. In conjunction with the advantages of glass, shape control of photoimageable dielectric lines during development and cure was developed and optimized. Single-mode polymer waveguides on glass were fabricated and characterized. Sample preparation methods and their impact on the sample edge quality and coupling loss will also be discussed in this article. Overall, this article presents the successful process development and demonstration of 3-mu m embedded trenches in the dielectric film for ultrafine copper traces and 2-mu m microvias for interlayer interconnects.