A 3D Integrated Circuit is a chip that has active electronic components stacked on one or more layers that are integrated both vertically and horizontally forming a single circuit.
In the 3-D design architecture, an entire chip is divided into a number of blocks, and each block is placed on a separate layer of Si that are stacked on top of each other.
In a generic 3D IC structure, each die is stacked on top of another and communicated by Through-Silicon Vias (TSVs).
Traditional shared buses do not scale well – bandwidth saturation
Chip IO is pad limited
On-chip Interconnects become increasingly slower w.r.t. logic
IOs are increasingly expensive
Design closure issues or infeasibility
Reduced wire length
Total wire length
Larger circuits produce more improvement
Lower power per transistor
Decreased interconnect delay
Higher transistor packing densities
Smaller chip areas
There are four ways to build a 3D IC:
Die On Die
At runtime, thermal variations will introduce additional time-varying clock skew, further increasing design uncertainty
2 - Thermal Issues In 3-D ICs
Due to reduction in chip size of a 3D implementation, 3D circuits exhibit a sharp increase in power density
Analysis of Thermal problems in 3D is necessary to evaluate thermal robustness of different 3D technology and design options.
3 - Reliability Issues In 3-D ICs
Electro thermal and Thermo-mechanical effects between various active layers can influence electro-migration and chip performance
Die yield issues may arise due to mismatches between die yields of different layers, which affect net yield of 3D chips.
TSV check on reset
Control use dedicated Vias in order to establish which vias are corrupted.
If 1, 2 and 3 TSVs are OK, the control set the enable signal set_to and set_from: broken path are skipped!
Pads routing shift as show in the figure
Need to define The handling protocol during the TSVs check
3D IC design is a relief to interconnect driven IC design.
Still many manufacturing and technological difficulties
Physical Design needs to consider the multiple layers of Silicon available.
Optimization of both temperature and wirelength
Placement and routing algorithms need to be modified
 J. Davis, et al., "Interconnect limits on gigascale integration (GSI) in the 21st century," Proceedings of the IEEE , vol.89, no.3, pp.305-324, Mar 2001.
 Banerjee, K.; Souri, S.J.; Kapur, P.; Saraswat, K.C.; , "3-D ICs: a novel chip design for improving deep- submicrometer interconnect performance and systems-on-chip integration," Proceedings of the IEEE , vol.89, no.5, pp.602-633, May 2001.