Abstract: An efficient method and computer program for modeling and improving stating memory performance across process variations and environmental conditions provides a mechanism for raising the performance of memory arrays beyond present levels/yields. Statistical (Monte-Carlo) analyses of subsets of circuit parameters are performed for each of several memory performance variables and then sensitivities of each performance variable to each of the circuit parameters are determined. The memory cell design parameters and/or operating conditions of the memory cells are then adjusted in conformity with the sensitivities, resulting in improved memory yield and/or performance. Once a performance level is attained, the sensitivities can then be used to alter the probability distributions of the performance variables to achieve a higher yield.

Abstract: A method for determining an interconnect delay at a node in an interconnect having a plurality of nodes. The method includes performing a bottom-up tree traversal to compute the first three admittance moments for each of the nodes in the interconnect. The computed admittance moments are utilized, in an advantageous embodiment, to compute a pi-model of the downstream load. Next, the equivalent effective capacitance value Ceff is computed utilizing the components of the computed pi-model and the Elmore delay at the node under evaluation. In an advantageous embodiment, Ceff is characterized by: Ceff=Cfj(1?e?T/?dj) where Cfj is the far-end capacitance of the pi-model at the node, T is the Elmore delay at the node and ?dj is the resistance of the pi-model (Rdj) multiplied by Cfj. The interconnect delay at the node is then determined utilizing an effective capacitance metric (ECM) delay model.

Abstract: A process for efficiently computing moments in an interconnected circuit begins by partitioning the circuit into sets of line-like two-port circuits. Next, capacitors are converted to equivalent current sources and inductors are converted to equivalent voltage sources. From a first port, any connected voltage source which is present in line is added to the port voltage source. Then, that voltage source combined with the connected resistor and the Thevenin equivalent circuit is converted to a Norton equivalent circuit. The current source created from the conversion is added to a current source in the circuit and the Norton equivalent circuit is converted back to a Thevenin equivalent circuit. The process is recursively performed until the opposite port is reached. The moment is then computed from the final Thevenin equivalent circuit by using the voltage and current at the port. The Thevenin-Norton-Thevenin recursive process is then repeated for the opposite port.