First Demonstration of Die-embedded Alumina Ribbon Ceramic (ARC) Packaging for 6G Wireless Applications

This work presents a first demonstration of die embedding in Alumina Ribbon Ceramic (ARC) as package substrate which is a recent development from Corning Inc. ARC is a thin, rigid, flat, low CTE and stable material which is suitable for substrate core compared to organic and silicon. It is also a durable substrate that conducts heat efficiently and is an excellent electrical insulator at high temperature. Looking at the electrical characteristics, dielectric constant of 10.12 ± 0.061, loss tangent of 0.000066 to 0.0013, microstrip line insertion loss of 0.019 to 0.293, and CPW line insertion loss of 0.026 to 0.24 dB/mm were measured over 3-170 GHz range. These low-loss, high dielectric constants make ARC an excellent substrate and packaging material for 6G applications. In this work, different thickness ARCs (40, 80, and 120 micrometers) are bonded in order to make the target thickness using ultra-thin ABF as the bonding adhesive layer. Cavity is drilled to the bonded ARC using a femtosecond laser drill for die placement. After the die is placed in the bonded ARC cavity, ABF is used for the build-up layer to encapsulate the die inside the cavity. Various thin dielectric films ranging from 5 - 15 micrometers in thickness including low loss ABF films were used for the lamination of die embedded ARC.