A three-dimensional stacked-chip star-wiring interconnection for a digital noise-free and low-jitter I/O clock distribution network

Abstract

Cascaded repeaters are indispensable circuit elements in conventional on-chip clock distribution networks due to heavy loss characteristics of on-chip global interconnections. However, cascaded repeaters cause significant jitter and skew problems in clock distribution networks when they are affected by power supply switching noise generated by digital logic blocks located on the same die. In this letter, we present a new three-dimensional (3-D) stacked-chip star-wiring interconnection scheme to make a clock distribution network free from both on-chip and package-level power supply noise coupling. The proposed clock distribution scheme provides an extremely low-jitter and low-skew clock signal by replacing the cascaded repeaters with lossless star-wiring interconnections on a 3-D stacked-chip package. We have demonstrated a 500-MHz input/output (I/O) clock delivery with 34-ps peak-to-peak jitter and a skew of 11 ps, while a conventional I/O clock scheme exhibited a 146-ps peak-to-peak jitter and a 177-ps skew in the same power supply noise environment.