Design checks for signal lines

• US 20060253819A1
• Filed: 07/12/2006
• Published: 11/09/2006
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Andrew Mcronald, Brett Neal, Gene Garrison, Lee Genz, Neal Meyer, Ping Sun
• Original Assignee: Andrew Mcronald, Brett Neal, Gene Garrison, Lee Genz, Neal Meyer, Ping Sun
• Inventors: Sun, Ping, McRonald, Andrew, Meyer, Neal, Neal, Brett, Genz, Lee, Garrison, Gene
• Granted Patent: US 7,421,673 B2
• Time in Patent Office: Days
• US Class Current: 716/106
• 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

Some embodiments provide identification of a first polyline and a second polyline associated with a differential signal, determination of whether a distance between a segment of the first polyline and a segment of the second polyline is within a first tolerance, determination, if the distance is not within the first tolerance, of whether the distance is within a second tolerance, determination, if the distance is not within the first tolerance and is within the second tolerance, of whether the length of the segment of the first polyline is less than a first threshold, and to indicate that the first polyline and the second polyline are sufficiently spaced, if the distance is not within the first tolerance and is within the second tolerance, and if the length of the segment of the first polyline is less than the first threshold.

Claims

1-4. -4. (canceled)

5. A method comprising:

marking all nodes of interest as virtual nodes;

identifying a node;

marking the node as visited;

determining if the node is a pin;

if the node is a pin, marking a path associated with the node as containing a pin;

determining if any connecting nodes are connected to the node;

incrementing a stub count if no connecting nodes are connected to the node; and

recursively applying the method to all of the connecting nodes that are marked as visited.

6. A method according to claim 5, further comprising:

outputting the stub count.

25. A method according to claim 5, further comprising:

determining if the node is a virtual node;

determining, if the node is a virtual node, if there are any pins on the path; and

incrementing the stub count and unmark the node as a virtual node if there are no pins on the path.

26. A method according to claim 25, further comprising:

determining, if it is determined that there are pins on the path, if all of the connecting nodes have been marked as visited; and

marking, if it is determined that all of the connecting nodes have been marked as visited, the node as a virtual node.

7-14. -14. (canceled)

15. A medium storing processor-executable code, the code comprising:

code to mark all nodes of interest as virtual nodes;

code to identify a node;

code to mark the node as visited;

code to determine if the node is a pin;

code to mark, if the node is a pin, a path associated with the node as containing a pin;

code to determine if any connecting nodes are connected to the node;

code to increment a stub count if no connecting nodes are connected to the node; and

code to recursively apply the method to all of the connecting nodes that are not marked as visited.

16. A medium according to claim 15, the code further comprising:

code to output the stub count.

27. A medium according to claim 15, the code further comprising:

code to determine if the node is a virtual node;

code to determine, if the node is a virtual node, if there are any pins on the path; and

code to increment the stub count and unmark the node as a virtual node if there are no pins on the path.

28. A medium according to claim 27, the code further comprising:

code to determine, if it is determined that there are pins on the path, if all of the connecting nodes have been marked as visited; and

code to mark, if it is determined that all of the connecting nodes have been marked as visited, the node as a virtual node.

17-24. -24. (canceled)