Glass Package With Multiple Embedded Dies for mmWave Applications

This article presents a multiple-die-embedded glass package that supports a thermal management solution for millimeter-wave (mmWave) applications. The package includes dies with different thicknesses embedded into isolated cavities created on a single glass substrate. In the package, partial cavities are used for embedding thin and low-power chips as well as passive components, while through cavities are used for thick and high-power chips. Connection to the embedded dies is facilitated through via transitions and transmission lines. Thermal management is integrated on the backside of the dies embedded in through cavities. This article discusses the design of interconnects along with the fabrication process for the package. The measured package broadband interconnect loss is less than 1 dB/mm from 40 MHz to 80 GHz, with a panel warpage of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$145~\mu $ </tex-math></inline-formula>m at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$30~^{\circ }$ </tex-math></inline-formula>C. A cross section of the package is also presented. The multidie-embedded glass package exhibits low-loss broadband performance and the ability to integrate thermal solutions, suggesting significant potential for module-level mmWave applications.