Chapter 2 provides an in-depth and intuitive description of TCI, starting with its basic structure and fundamental operating principle. It explains how the transceiver and inductive coupling coils are designed, their electrical characteristics, and design variations. This is followed by an intuitive explanation of how to do design trade-offs to optimize for different performance requirements, with particular emphasis on design options for optimal power and area efficiency respectively. Integration options – 2/2.5/2.9/3D – are also presented to illustrate implementation flexibility. Two power delivery solutions are then introduced, one using wireless and the other advanced doping technologies. Next, three application examples are described, providing insight into how TCI can be adopted and adapted and quantifying performance improvement against conventional wideband DRAM, stacked flash memory, and network-on-chip solutions. Specific challenges in each of the application areas are elaborated and how TCI can be adapted to address these challenges is explained. The chapter concludes with two postscripts. The first introduces a sample of TCI research carried out in other institutions in parallel to our effort. The second provides an overview of collective synchronization, which is utilized to create a low-cost clock distribution solution for TCI.

Chapter 1 starts by tracing the history of the computer, integrated circuit (IC), and connector in the last 60 years. In particular, it describes how the goal of IC development evolved from high-performance IC to low-power IC and interface, and then to high energy efficiency. This provides the background to help the reader understand current and future challenges faced by the IC and connector in addressing the diverging performance needs of various emerging applications. This in turn sets the stage for the introduction of 3D IC integration, which is evolving from low-cost wirebond to high-performance and high-density TSV-based solutions to offer More than Moore performance improvement. The challenges faced by 3D integration are then enumerated, and 2.5D integration and wireless interface technologies are presented as current and future solutions respectively. A brief overview of wireless technologies is then provided, followed by an explanation of why near-field coupling has been applied to develop two wireless interface technologies – ThruChip Interface (TCI) and Transmission Line Coupler (TLC). The chapter concludes with an overview of TCI and TLC and an elaboration of how they address respectively the challenges in 3D IC integration and connector performance scaling.