Contactless three-dimensional (3-D) interconnects have been proposed
as an alternative to through-silicon via (TSV) due to its manufacturing
compatibility with two-dimensional (2-D) processes. Typically,
contactless 3-D circuits are thought to require considerable
silicon resources compared to TSV. However, recent manufacturing
options, such as extreme wafer thinning, provide new opportunities
for this approach. This paper, therefore, explores these opportunities
for producing 3-D systems of lower cost. The presented cost analysis and models usefully combine fabrication cost with performance requirements for inter-tier communication as a critical component of 3-D systems. Thus, benchmark circuits are simulated for a two-tier system using a commercial 65 푛푚 technology and communicating at a data rate of 1퐺푏푝푠 per link, although the model is directly applicable to any technology or design specifications.
Interestingly, inductive links can be a useful alternative to TSV for specific and expected manufacturing capabilities. Furthermore, the effectiveness of different multiplexing schemes and their effect on system cost is also evaluated.