Modifying a hierarchical representation of a circuit to process composite gates

• US 6,738,958 B2
• Filed: 09/10/2001
• Issued: 05/18/2004
• Est. Priority Date: 09/10/2001
• Status: Active Grant

• Current Assignee: Synopsys Merger Holdings LLC (Synopsys Incorporated)
• Original Assignee: Numerical Technologies Inc. (Synopsys Incorporated)
• Inventors: Manoo, Masoud
• Primary Examiner(s): Siek, Vuthe
• Application Number:
  US09/953,119
• Publication Number:
  US 20030051219A1
• Time in Patent Office: 981 Days
• Field of Search: 716/1-21, 430/5
• US Class Current: 716/111
• CPC Class Codes: G06F 30/398 Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] optical proximity correction [OPC] design processes G03F1/36

Abstract

One embodiment of the invention provides a system for analyzing a layout related to a circuit on a semiconductor chip. The system operates by receiving a design hierarchy specifying the layout of the circuit. This design hierarchy includes a set of hierarchically organized nodes, wherein a given node in the design hierarchy specifies a geometrical feature that is comprised of lower-level geometrical features that are represented by lower-level nodes located under the given node in the design hierarchy. The system modifies the design hierarchy by, examining a set of sibling nodes that are located under a parent node in the design hierarchy in order to identify a set of interacting geometrical features between the set of sibling nodes. The system then moves the set of interacting geometrical features from the sibling nodes to the parent node, so that the interaction is visible at the parent node. Note that other geometrical features that do not interact remain at the sibling nodes and are not moved to the parent node. The system then performs an analysis on the modified design hierarchy. This involves analyzing the set of interacting geometrical features at the parent node.

Claims

1. A method for analyzing a layout related to a circuit on a semiconductor chip, comprising:

receiving a design hierarchy specifying the layout of the circuit, including a set of hierarchically-organized nodes;

wherein a given node in the design hierarchy specifies a geometrical feature that is comprised of lower-level geometrical features that are represented by lower-level nodes located under the given node in the design hierarchy;

modifying the design hierarchy to produce a modified design hierarchy by,

examining a set of sibling nodes that are located under a parent node in the design hierarchy,

identifying a set of interacting geometrical features between the set of sibling nodes, and

moving the set of interacting geometrical features from the sibling nodes to the parent node, so that the interaction is visible at the parent node,

wherein other geometrical features that do not interact remain at the sibling nodes and are not moved to the parent node;

performing an analysis on the modified design hierarchy;

identifying other sets of sibling nodes with equivalent sets of interacting geometrical features; and

using results from analyzing the set of interacting geometrical features in analyzing the equivalent sets of interacting geometrical features, so that the analysis does not have to be repeated for the equivalent sets of interacting geometrical features;

wherein performing the analysis involves analyzing the set of interacting geometrical features at the parent node.

2. The method of claim 1, wherein performing the analysis involves:

identifying transistors and associated transistor endcaps within the circuit;

wherein the set of interacting geometrical features defines at least some of the transistors and associated transistor endcaps; and

generating phase shifters to be used in fabricating some of the identified transistors;

wherein the layout of a given phase shifter is affected by a location of an associated endcap for the given phase shifter.

3. The method of claim 1, further comprising determining at a parent node whether interactions between related sibling nodes cause transistor endcaps to become fieldcaps, and if so, moving geometrical features that caused the interactions to the parent node.

4. The method of claim 1, wherein modifying the design hierarchy additionally involves:

identifying a second set of interacting geometrical features between the parent node and the set of sibling nodes; and

moving the second set of interacting geometrical features from the set of sibling nodes to the parent node.

5. The method of claim 1, wherein the set of interacting geometrical features define polysilicon regions and diffusion regions on the semiconductor chip.

6. The method of claim 1, wherein the layout can define:

features on the semiconductor chip; and

a mask that is used to create features on the semiconductor chip.

7. The method of claim 1, wherein the design hierarchy is specified in GDSII format.

8. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for analyzing a layout related to a circuit on a semiconductor chip, the method comprising:

receiving a design hierarchy specifying the layout of the circuit, including a set of hierarchically-organized nodes;

wherein a given node in the design hierarchy specifies a geometrical feature that is comprised of lower-level geometrical features that are represented by lower-level nodes located under the given node in the design hierarchy;

modifying the design hierarchy to produce a modified design hierarchy by,

examining a set of sibling nodes that are located under a parent node in the design hierarchy,

identifying a set of interacting geometrical features between the set of sibling nodes, and

moving the set of interacting geometrical features from the sibling nodes to the parent node, so that the interaction is visible at the parent node,

wherein other geometrical features that do not interact remain at the sibling nodes and are not moved to the parent node;

performing an analysis on the modified design hierarchy;

identifying other sets on sibling nodes with equivalent sets of interacting geometrical features; and

using results from analyzing the set of interacting geometrical features in analyzing the equivalent sets of interacting geometrical features so that the analysis does not have to be repeated for the equivalent sets of interacting geometrical features;

wherein performing the analysis involves analyzing the set of interacting geometrical features at the parent node.

9. The computer-readable storage medium of claim 8, wherein performing the analysis involves:

identifying transistors and associated transistor endcaps within the circuit;

wherein the set of interacting geometrical features defines at least some of the transistors and associated transistor endcaps; and

generating phase shifters to be used in fabricating some of the identified transistors;

wherein the layout of a given phase shifter is affected by a location of an associated endcap for the given phase shifter.

10. The computer-readable storage medium of claim 9, wherein the method further comprises, determining at a parent node whether interactions between related sibling nodes cause transistor endcaps to become fieldcaps, and if so, moving geometrical features that caused the interactions to the parent node.

11. The computer-readable storage medium of claim 8, wherein modifying the design hierarchy additionally involves:

identifying a second set of interacting geometrical features between the parent node and the set of sibling nodes; and

moving the second set of interacting geometrical features from the set of sibling nodes to the parent node.

12. The computer-readable storage medium of claim 8, wherein the set of interacting geometrical features define polysilicon regions and diffusion regions on the semiconductor chip.

13. The computer-readable storage medium of claim 8, wherein the layout can define:

features on the semiconductor chip; and

a mask that is used to create features on the semiconductor chip.

14. The computer-readable storage medium of claim 8, wherein the design hierarchy is specified in GDSII format.

15. An apparatus for analyzing a layout related to a circuit on a semiconductor chip, comprising:

a receiving mechanism that is configured to receive a design hierarchy specifying the layout of the circuit, including a set of hierarchically-organized nodes;

wherein a given node in the design hierarchy specifies a geometrical feature that is comprised of lower-level geometrical features that are represented by lower-level nodes located under the given node in the design hierarchy;

a modification mechanism that is configured to modify the design hierarchy to produce a modified design hierarchy;

wherein the modification mechanism is configured to,

identify a set of interacting geometrical features between a set of sibling nodes that are located under a parent node in the design hierarchy, and to

move the set of interacting geometrical features from the sibling nodes to the parent node, so that the interaction is visible at the parent node,

wherein other geometrical features that do not interact remain at the sibling nodes and are not moved to the parent node;

an analysis mechanism that is configured to perform an analysis on the modified design hierarchy; and

an identification mechanism that is configured to identify other sets of sibling nodes with equivalent sets of interacting geometrical features;

wherein the analysis mechanism is configured to use results from analyzing the set of interacting geometrical features in analyzing the equivalent sets of interacting geometrical features, so that the analysis does not have to be repeated for the equivalent sets of interacting geometrical features; and

wherein performing the analysis involves analyzing the set of interacting geometrical features at the parent node.

16. The apparatus of claim 15, wherein the modification mechanism is additionally configured to:

identify transistors and associated transistor endcaps within the circuit;

wherein the set of interacting geometrical features defines at least some of the transistors and associated transistor endcaps; and

to

generate phase shifters to be used in fabricating some of the identified transistors;

wherein the layout of a given phase shifter is affected by a location of an associated endcap for the given phase shifter.

17. The apparatus of claim 16, wherein the apparatus is further configured to determine at a parent node whether interactions between related sibling nodes cause transistor endcaps to become fieldcaps, and if so, to move geometrical features that caused the interactions to the parent node.

18. The apparatus of claim 16, wherein the modification mechanism is additionally configured to:

identify a second set of interacting geometrical features between the parent node and the set of sibling nodes; and

to

move the second set of interacting geometrical features from the set of sibling nodes to the parent node.

19. The apparatus of claim 16, wherein the set of interacting geometrical features define polysilicon regions and diffusion regions on the semiconductor chip.

20. The apparatus of claim 16, wherein the layout can define:

features on the semiconductor chip; and

a mask that is used to create features on the semiconductor chip.

21. The apparatus of claim 16, wherein the design hierarchy is specified in GDSII format.

22. A means for analyzing a layout related to a circuit on a semiconductor chip, comprising:

a receiving means for receiving a design hierarchy specifying the layout of the circuit, including a set of hierarchically-organized nodes;

wherein a given node in the design hierarchy specifies a geometrical feature that is comprised of lower-level geometrical features that are represented by lower-level nodes located under the given node in the design hierarchy;

a modification means for modifying the design hierarchy to produce a modified design hierarchy;

wherein the modification means includes,

an examination means for examining a set of sibling nodes that are located under a parent node in the design hierarchy,

an identification means for identifying a set of interacting geometrical features between the set of sibling nodes, and

a moving means for moving the set of interacting geometrical features from the sibling nodes to the parent node, so that the interaction is visible at the parent node,

wherein other geometrical features that do not interact remain at the sibling nodes and are not moved to the parent node;

an analysis means for performing an analysis on the modified design hierarchy; and

an identification means for identifying other sets of sibling nodes with equivalent sets of interacting geometrical features;

wherein the analysis means uses results from analyzing the set of interacting geometrical features in analyzing the equivalent sets of interacting geometrical features, so that the analysis does not have to be repeated for the equivalent sets of interacting geometrical features; and

wherein performing the analysis involves analyzing the set of interacting geometrical features at the parent node.