335
Three-Dimensional Integration of Network-on-Chip
≈20 μm
≈ 5 m m
≈10 mm
Figure 11.10
A 3D 2 × 2 × 4 MoT network.
of 2 compared to its 2D structure. It can be observed from Figure 11.10 that
the links between leaf and root routers of the column tree in each layer
are tens of micrometers long. The length of the interlayer links is 20 μm.
Hence, like BFT, the root nodes of the column trees and the vertical trees
(shown as dotted node in Figure 11.10) of the proposed MoT-based 3D NoC
is bypassed. Here, it is customary to say that for larger number of cores in
each layer, mesh structures are planer, whereas BFT and MoT networks
require two metal layers to route the links. Moreover, the wire density of
mesh networks is more uniform across any given cross section than that of
BFT and MoT.