3-D Capacitive Interconnections With Mono- and Bi-Directional Capabilities

Abstract

A wireless interconnection scheme based on capacitive coupling provides mono-and bi-directional transmission capabilities for 3-D system integration. Chips are implemented in 0.13 m CMOS technology and assembled face-to-face at die-level. RX-TX circuits are specifically designed for low-power functionality and the implementation takes advantage of the two different voltage thresholds that are available for the standard transistors in the CMOS process we used. The communication circuits are coupled via electrodes with an area down to 8 8 m 2 and this enables the vertical propagation of clock signals at 1.7 GHz, a propagation delay of 420 ps for general purpose signals and a throughput of more than 22 Mb/s m 2 with 0.08 pJ/b energy consumption.

Device Requirements for Optical Interconnects to Silicon Chips

“…Capacitively coupled proximity communication directly between chips allows particularly high densities of interconnections with similarly low energies [53], and there is a variety of other approaches also for dense short vertical "3-D" connections between chips or active circuit layers [54]. Recent work [55] shows energies as low as 80 fJ/bit in such 3-D capacitive connections in 130 nm silicon technology, for example, for face-to-face chips. We have argued above that it is unlikely that any new interconnect technology can be introduced that takes more energy than the existing electrical approaches.…”

“…At an example optical pad size of 10 µm x 10 µm, the total area consumed by the pads would be 5.5 mm 2 , a very small fraction of the 310 mm 2 chip area, so we are not near to any limit of available area. (The pad sizes of such interconnects would be comparable to current 3-D electrical vertical chip-to-chip interconnects [55], but they would not necessarily be restricted to the very close proximity connections of such electrical schemes. )…”

Implantable Biomedical Devices

“…The idea of capacitive coupling has been already used for inter-chip data communication [82] and power transfer [83], and also for sensing biomedical signals [84,85]. In this approach a capacitor is formed between two parallel plates, one implanted and the other one attached to the outer part of the skin.…”

Wireless Telemetry for Implantable Biomedical Microsystems

“…Although capacitive coupling has been already used for inter-chip data communication (Canegallo et al, 2007;Fazzi et al, 2008) and even for power transfer (Culurciello & Andreou, 2006), it was studied for implantable biomedical applications in (Sodagar & Amiri, 2009) for the first time. This method is based on capacitive coupling between two parallel plates.…”