Interconnect Prediction Models

Interconnect prediction models aim at providing a distribution of the length of the nets within a circuit without any prior knowledge of the physical design of the circuit. This a priori distribution can be utilized in a general interconnect prediction framework, producing estimates for various design objectives. Interconnect prediction models have existed for a long time. Recently, these models have evolved to consider interconnect issues, such as placement and routing for interconnect-dominated circuits, interconnect delay, and crosstalk noise. The majority of these models are based on either empirical heuristics or rules. A well-known rule, Rent’s rule, forms the basis for the majority of interconnect prediction models. This chapter discusses this rule and a related interconnect prediction model for 2-D circuits. It presents several interconnect prediction models adapted for 3-D circuits. It discusses projections for 3-D circuits obtained from these models that demonstrate the opportunities of vertical integration. Rent’s rule correlates the number of terminals of a circuit with the number of modules that constitute the circuit and the average number of terminals in each module. The granularity of the module can vary from a single gate to an entire subcircuit.