Hierarchical feature extraction for electrical interaction calculations
View Patent ↗A method of calculating electrical interactions of circuit elements in an integrated circuit layout without flattening the entire database that describes the layout. In one embodiment, a hierarchical database is analyzed and resistance and capacitance calculations made for a repeating pattern of elements are re-used at each instance of the repeated pattern and adjusted for local conditions. In another embodiment, a circuit layout is converted into a number of tiles, wherein the resistance and capacitance calculations made for the circuit elements in the center and a boundary region of the tiles are computed separately and combined. Environmental information that affects electrical interaction between circuit elements in different levels of hierarchy is calculated at a lower level of hierarchy so that such calculations do not need to be made for each placement of a repeated cell and so that not all interacting elements need to be promoted to the same hierarchy level to compute the electrical interactions.
1. A computer-implemented method for performing parasitic extraction for an integrated circuit layout representing an integrated circuit, comprising:
creating within a computer memory, a hierarchical database comprising cells that represent the integrated circuit layout, one or more of the cells comprising data defining one or more polygons that define size and location of circuit components in the integrated circuit layout;
computing parasitic extraction values for the one or more of the cells in the integrated circuit layout, wherein the parasitic extraction values for the one or more of the cells include both resistances and capacitances; and
based on the parasitic extraction values for the one or more of the cells, computing parasitic extraction values for interacting ones of the cells to represent electrical behavior between one or more of the circuit components of the integrated circuit layout.
2. The computer-implemented method of claim 1 , wherein the method further comprises:
representing the computed capacitances as a hierarchy that is derived from a hierarchy of the integrated circuit layout.
3. The computer-implemented method of claim 2 , wherein the hierarchy for representing the computed capacitances is the same as the hierarchy of the integrated circuit layout.
4. The computer-implemented method of claim 1 , wherein the computing of the parasitic extraction values for the one or more of the cells comprises computing inductances.
5. The computer-implemented method of claim 4 , further comprising representing the computed inductances as a hierarchy that is derived from a hierarchy of the integrated circuit layout.
6. The computer-implemented method of claim 1 , wherein the interacting ones of the cells are located in a lower hierarchy level and in a higher hierarchy level of the hierarchical database, and wherein the method further comprises:
re-using the parasitic extraction values computed for the interacting ones of the cells in the lower hierarchy level as the parasitic extraction values for the interacting ones of the cells in the higher hierarchy level.
7. One or more computer-readable memory or storage devices storing computer-executable instructions for performing a method for extracting electrical properties from an integrated circuit layout, the method comprising:
creating a hierarchical database for the integrated circuit layout in computer memory, the hierarchical database comprising one or more cells that specify a location and size of polygons that define integrated circuit elements within the cell; and
performing parasitic extraction using the hierarchical database of the integrated circuit layout, the parasitic extraction including computing both capacitances and resistances for the one or more cells and accounting for parasitic effects between adjacent polygons from different cells.
8. The computer-readable memory or storage devices of claim 7 , wherein the method further comprises creating a hierarchical database of the capacitance values.
9. The computer-readable memory or storage devices of claim 8 , wherein a hierarchy of the hierarchical database of the capacitance values is derived from the hierarchical representation for the integrated circuit layout.
10. The computer-readable memory or storage devices of claim 7 , wherein the performing parasitic extraction comprises computing inductance values, and wherein the method further comprises creating a hierarchical database of the inductance values.
11. The computer-readable memory or storage devices of claim 10 , wherein a hierarchy of the hierarchical database of the inductance values is derived from the hierarchical representation for the integrated circuit layout.
12. A computing device configured to perform a method for performing parasitic extraction for an integrated circuit layout representing an integrated circuit, the method comprising:
creating within a computer memory, a hierarchical database comprising cells that represent the integrated circuit layout, one or more of the cells comprising data defining one or more polygons that define size and location of circuit components in the integrated circuit layout;
computing parasitic extraction values for the one or more of the cells in the integrated circuit layout, wherein the parasitic extraction values for the one or more of the cells include both resistances and capacitances; and
based on the parasitic extraction values for the one or more of the cells, computing parasitic extraction values for interacting ones of the cells to represent electrical behavior between one or more of the circuit components of the integrated circuit layout.
13. The computing device of claim 12 , wherein the method further comprises:
representing the computed capacitances as a hierarchy that is derived from a hierarchy of the integrated circuit layout.
14. The computing device of claim 13 , wherein the hierarchy for representing the computed capacitances is the same as the hierarchy of the integrated circuit layout.
15. The computing device of claim 14 , wherein the computing of the parasitic extraction values for the one or more of the cells comprises computing inductances, and wherein the method further comprises:
representing the computed inductances as a hierarchy that is derived from a hierarchy of the integrated circuit layout.