US 7,849,427 B2Granted

Auto-router performing simultaneous placement of signal and return paths

AssigneeInternational Business Machines Corporation

InventorsMichael A. Christo, Julio A. Maldonado, Roger D. Weekly, Tingdong Zhang

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Abstract

An auto routing method and system provides optimized circuit routing while maintaining proper reference return paths for critical signals. Critical signal paths are auto-routed simultaneously with corresponding reference return paths, and the reference return paths can be merged into reference planes if they are adjacent to regions connected to the same reference net. The reference return paths may be in a plane adjacent to the signal path plane in the same channel, or the reference returns may be routed in adjacent channels in the same plane as the signal path. A check may be performed on endpoints of each critical signal path to determine whether a reference return via is present within a proximity tolerance of the signal path endpoints, and a reference return via placed if not.

Claims20

Dependent claims

A computer-performed method of designing an electrical circuit interconnect structure, comprising:

in a computer model of an interconnect structure design, routing, using a computer, a first conductive path for a critical signal using auto-routing algorithm;
prior to accepting the first conductive signal path as a routed path according to an auto-routing path acceptance criteria, routing a second conductive path for a reference return corresponding to the critical signal proximate the first conductive path, wherein the auto-routing path acceptance criteria requires meeting criteria for placement of both the signal path and the reference return path;
responsive to meeting the auto-routing path acceptance criteria for both of the first conductive path and the second conductive path, accepting the first conductive path and the second conductive path as a routed pair for the critical signal and the corresponding reference return;
responsive to not meeting the auto-routing path acceptance criteria for either of the first conductive path or the second conductive path, repeating the routing of the first conductive signal path using another routing and repeating the routing of the second conductive signal path;
and
repeating the routing a first conductive path, routing a second conductive path and accepting for other critical signals.

3 more elements

A computer program product comprising a non-transitory computer-readable storage media containing program instructions for execution by a processor for designing an electrical circuit interconnect structure, the program instructions comprising program instructions for:

in a computer model of an interconnect structure design, routing a first conductive path for a critical signal using auto-routing algorithm;
prior to accepting the first conductive signal path as a routed path according to an auto-routing path acceptance criteria, routing a second conductive path for a reference return corresponding to the critical signal proximate the first conductive path, wherein the auto-routing path acceptance criteria requires meeting criteria for placement of both the signal path and the reference return path;
responsive to meeting the auto-routing path acceptance criteria for both of the first conductive path and the second conductive path, accepting the first conductive path and the second conductive path as a routed pair for the critical signal and the corresponding reference return;
responsive to not meeting the auto-routing path acceptance criteria for either of the first conductive path or the second conductive path, repeating the routing of the first conductive signal path using another routing and repeating the routing of the second conductive signal path;
and
repeating the routing a first conductive path, routing a second conductive path and accepting for other critical signals.

3 more elements

A workstation computer system, comprising a processor for executing program instructions and a memory for storing the program instructions and data, wherein the program instructions include program instructions for designing an electrical circuit interconnect structure, the program instructions comprising program instructions for:

in a computer model of an interconnect structure design, routing a first conductive path for a critical signal using auto-routing algorithm;
prior to accepting the first conductive signal path as a routed path according to an auto-routing path acceptance criteria, routing a second conductive path for a reference return corresponding to the critical signal proximate the first conductive path, wherein the auto-routing path acceptance criteria requires meeting criteria for placement of both the signal path and the reference return path;
responsive to meeting the auto-routing path acceptance criteria for both of the first conductive path and the second conductive path, accepting the first conductive path and the second conductive path as a routed pair for the critical signal and the corresponding reference return;
responsive to not meeting the auto-routing path acceptance criteria for either of the first conductive path or the second conductive path, repeating the routing of the first conductive signal path using another routing and repeating the routing of the second conductive signal path;
and
repeating the routing a first conductive path, routing a second conductive path and accepting for other critical signals.

3 more elements

Dependencies are inferred from the claim text.