Inter-signal proximity verification in an integrated circuit

• US 6,807,657 B2
• Filed: 07/19/2002
• Issued: 10/19/2004
• Est. Priority Date: 07/19/2002
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Moldauer, Peter Shaw, Frank, Mark D., Nelson, Jerimy
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): ROSSOSHEK, YELENA
• Application Number:
  US10/199,331
• Publication Number:
  US 20040015806A1
• Time in Patent Office: 823 Days
• Field of Search: 703/15, 702/189, 324/763, 324/537, 324/536, 716/1, 716/2, 716/4, 716/5, 716/6, 716/7, 716/8, 716/10, 716/11, 716/13, 716/18, 714/739, 714/738, 714/726
• US Class Current: 716/139
• CPC Class Codes: G06F 30/394 Routing G06F30/396 takes precedence
• 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

In one aspect, techniques are disclosed for identifying and notifying a circuit designer of signal traces in an integrated circuit design that are closer to each other than a proximity threshold. It is desirable that signal traces be separated from each other by at least the proximity threshold to reduce inter-signal crosstalk to an acceptable level. Such notification may occur either dynamically (while the circuit designer is designing the circuit) or through a report generated after the circuit design has been generated. In another aspect, techniques are disclosed for identifying and notifying the circuit designer of the signal traces that are closest to a reference signal trace. Such notification may provide the circuit designer with feedback about regions in the circuit design which are congested and which may therefore produce an unacceptable level of crosstalk.

Claims

1. A computer-implemented method comprising steps of:

(A) identifying a first signal net in a first layer of an integrated circuit design;

(B) identifying a second signal net in a second layer of the integrated circuit design;

(C) determining whether at least one portion of the second signal net is within a threshold distance of the first signal net;

(D) if it is determined that at least one portion of the second signal net is within the threshold distance of the first signal net, measuring the aggregate length along the first signal net that is within the threshold distance of the second signal net;

(E) determining whether the measured length is at least as great as a threshold length; and

(F) notifying a user that the second signal net is a neighbor of the first signal net if it is determined that the measured length is at least as great as the threshold length.

2. The method of claim 1, wherein the step (A) comprises a step of:

(A) (1) identifying a first signal net being edited by the user using an integrated circuit design tool; and

wherein the step (F) comprises a step of;

(F) (1) notifying the user that the second signal net is within the threshold distance of the first signal net while the user is editing the first signal net.

3. The method of claim 2, wherein the step (F) (1) comprises a step of providing to the user a visual indication of the second signal net.

4. The method of claim 3, wherein the step (F) (1) comprises a step of providing to the user a visual indication of coordinates on the first signal net, which are within the threshold distance of the second signal net.

5. The method of claim 1, wherein the first signal net comprises a first plurality of signal nets, and wherein the steps (A)-(F) are performed for each of the first plurality of signal nets.

6. The method of claim 1, wherein the step (B) comprises a step of identifying the second signal net from among a plurality of second signal nets, and wherein the steps (C)-(F) are repeated for each of the plurality of second signal nets.

7. The method of claim 1, wherein the step (F) comprises a step of generating a report identifying the first signal net and the second signal net.

8. The method of claim 7, wherein the first signal net comprises a first plurality of signal nets, and wherein the steps (A)-(F) are performed for each of the first plurality of signal nets.

9. The method of claim 1, wherein the integrated circuit design comprises a computer-implemented model of an integrated circuit tangibly stored in a computer-readable medium.

10. The method of claim 1, wherein the step (C) comprises steps of:

(C)(1) measuring a distance between the at least one portion of the second signal net and the first signal net, wherein the distance includes both a non-zero horizontal component and a non-zero vertical component; and

(C)(2) determining whether the measured distance is less than the threshold distance.

11. A computer-implemented system comprising:

first identification means for identifying a first signal net in a first layer of an integrated circuit design;

second identification means for identifying a second signal net in a second layer of the integrated circuit design;

first determination means for determining whether at least one portion of the second signal net is within a threshold distance of the first signal net;

measurement means for measuring the aggregate length along the first signal net that is within the threshold distance of the second signal net if it is determined that at least one portion of the second signal net is within the threshold distance of the first signal net;

second determination means for determining whether the measured length is at least as great as a threshold length; and

notification means for notifying a user that the second signal net is a neighbor of the first signal net if it is determined that the measured length is at least as great as the threshold length.

12. The system of claim 11, wherein the first identification means comprises means for identifying a first signal net being edited by the user using an integrated circuit design tool;

and wherein the notification means comprises means for notifying the user that the at least one second signal net is within the threshold distance of the first signal net while the user is editing the first signal net.

13. The system of claim 12, wherein the notification means comprises means for providing to the user a visual indication of the second signal net.

14. The system of claim 13, wherein the notification means comprises means for providing to the user a visual indication of coordinates on the first signal net, which are within the threshold distance of the second signal net.

15. The system of claim 11, wherein the first signal net comprises a first plurality of signal nets, and wherein the system further comprises means for applying the first identification means, the second identification means, the first determination means, the measurement means, the second determination means, and the notification means to each of the first plurality of signal nets.

16. The system of claim 11, wherein the second identification means comprises means for identifying the second signal net from among a plurality of second signal nets, and wherein the system further comprises means for applying the first determination means, the measurement means, the second determination means, and the notification means to each of the plurality of second signal nets.

17. The system of claim 11, wherein the notification means comprises means for generating a report identifying the first signal net and the second signal net.

18. The system of claim 17, wherein the first signal net comprises a first plurality of signal nets, and wherein the system further comprises means for applying the first identification means, the second identification means, the first determination means, the measurement means, the second determination means, and the notification means to each of the first plurality of signal nets.

19. The system of claim 11, wherein the integrated circuit design comprises a computer-implemented model of an integrated circuit tangibly stored in a computer-readable medium.

20. The system of claim 11, wherein the first determination means comprises:

means for measuring a distance between the at least one portion of the second signal net and the first signal net, wherein the distance includes both a non-zero horizontal component and a non-zero vertical component; and

means for determining whether the measured distance is less than the threshold distance.

21. A computer-readable medium tangibly embodying computer program instructions for performing steps of:

(A) identifying a first signal net in a first layer of an integrated circuit design;

(B) identifying a second signal net in a second layer of the integrated circuit design;

(C) determining whether at least one portion of the second signal net is within a threshold distance of the first signal net;

(D) if it is determined that at least one portion of the second signal net is within, the threshold distance of the first signal net, measuring the aggregate length along the first signal net that is within the threshold distance of the second signal net;

(E) determining whether the measured length is at least as great as a threshold length; and

(F) notifying a user that the second signal net is a neighbor of the first signal net if it is determined that the measured length is at least as great as the threshold length.

22. The computer-readable medium of claim 21, wherein the computer program instructions for performing the step (A) comprise instructions for performing a step of:

(A) (1) identifying a first signal net being edited by the user using an integrated circuit design tool; and

wherein the computer program instructions for performing the step (F) comprise instructions for performing a step of;

(F) (1) notifying the user that the second signal net is within the threshold distance of the first signal net while the user is editing the first signal net.

23. The computer-readable medium of claim 22, wherein the computer program instructions for performing the step (F) (1) comprise instructions for performing a step of providing to the user a visual indication of the second signal net.

24. The computer-readable medium of claim 23, wherein the computer program instructions for performing the step (F) (1) comprise instructions for performing a step of providing to the user a visual indication of coordinates on the first signal net, which are within the threshold distance of the second signal net.

25. The computer-readable medium of claim 21, wherein the first signal net comprises a first plurality of signal nets, and wherein the computer program instructions comprise instructions for performing the steps (A)-(F) for each of the first plurality of signal nets.

26. The computer-readable medium of claim 21, wherein the computer program instructions for performing the step (B) comprise instructions for performing a step of identifying the second signal net from among a plurality of second signal nets, and wherein the computer program instructions comprise instructions for repeating the steps (C)-(F) for each of the plurality of second signal nets.

27. The computer-readable medium of claim 21, wherein the computer program instructions for performing the step (F) comprise instructions for performing a step of generating a report identifying the first signal net and the second signal net.

28. The computer-readable medium of claim 27, wherein the first signal net comprises a first plurality of signal nets, and wherein the computer program instructions comprise instructions for performing the steps (A)-(F) for each of the first plurality of signal nets.

29. The computer-readable medium of claim 21, wherein the integrated circuit design comprises a computer-implemented model of an integrated circuit tangibly stored in a computer-readable medium.

30. The computer-readable medium of claim 21, wherein the computer program instructions for performing the step (C) comprise instructions for performing steps of:

(C) (1) measuring a distance between the at least one portion of the second signal net and the first signal net, wherein the distance includes both a non-zero horizontal component and a non-zero vertical component; and

(C) (2) determining whether the measured distance is less than the threshold distance.

31. A computer-implemented method comprising steps of:

(A) identifying a first signal net in an integrated circuit design;

(B) identifying a plurality of second signal nets in the integrated circuit design;

(C) identifying a subset of the plurality of second signal nets that are closest to the first signal net by performing steps of;

(C) (1) sorting the plurality of second signal nets according to distances between the first signal net and the plurality of second signal nets to produce a sorted signal net list;

(C)(2) identifying a number NC; and

(C)(3) identifying the first NC signal nets in the sorted signal net list as the subset of the plurality of second signal nets; and

(D) notifying a user of the subset of the plurality of second signal nets.

32. The method of claim 31, wherein the step (A) comprises a step of:

(A) (1) identifying a first signal net being edited by the user using an integrated circuit design tool; and

wherein the step CD) comprises a step of;

(D) (1) notifying the user of the plurality of second signal nets while the user is editing the first signal net.

33. The method of claim 32, wherein the step (D) (1) comprises a step of providing to the user a visual indication of the at least one second signal net.

34. The method of claim 33, wherein the step CD) (1) comprises a step of providing to the user a visual indication of coordinates on the first signal net, which are closest to the subset of the plurality of second signal nets.

35. The method of claim 31, wherein the first signal net comprises a first plurality of signal nets, and wherein the method further comprises a step of performing the steps (A), (B), (C), and (D) for each of the first plurality of signal nets.

36. The method of claim 31, wherein the step (D) comprises a step of generating a report identifying the first signal net and the subset of the plurality of second signal nets.

37. The method of claim 36, wherein the first signal net comprises a first plurality of signal nets, and wherein the method further comprises a step of performing the steps (A), (B), (C), and (D) for each of the first plurality of signal nets.

38. The method of claim 31, wherein the integrated circuit design comprises a computer-implemented model of an integrated circuit tangibly stored in a computer-readable medium.

39. The method of claim 31, wherein the step (A) comprises a step of identifying the first signal net in a first layer of the integrated circuit design, and wherein the subset identified in the step (C) includes at least one signal net in a second layer of the integrated circuit design.

40. A computer-implemented system comprising:

first identification means for identifying a first signal net in an integrated circuit design;

second identification means for identifying a plurality of second signal nets in the integrated circuit design;

subset identification means for identifying a subset of the plurality of second signal nets that are closest to the first signal net, the subset identification means comprising;

means for sorting the plurality of second signal nets according to distances between the first signal net and the plurality of second signal nets to produce a sorted signal net list;

means for identifying a number NC; and

means for identifying the first NC signal nets in the sorted signal net list as the subset of the plurality of second signal nets; and

notification means for notifying a user of the subset of the plurality of second signal nets.

41. The system of claim 40, wherein the first identification means comprises:

means for identifying a first signal net being edited by the user using an integrated circuit design tool; and

wherein the notification means comprises;

means for notifying the user of the plurality of second signal nets while the user is editing the first signal net.

42. The system of claim 41, wherein the notification means comprises means for providing to the user a visual indication of the at least one second signal net.

43. The system of claim 42, wherein the notification means comprises means for providing to the user a visual indication of coordinates on the first signal net, which are closest to the subset of the plurality of second signal nets.

44. The system of claim 40, wherein the first signal net comprises a first plurality of signal nets, and wherein the system further comprises means for applying the first identification means, the second identification means, the subset identification means, and the notification means to each of the first plurality of signal nets.

45. The system of claim 40, wherein the notification means comprises a step of generating a report identifying the first signal net and the subset of the plurality of second signal nets.

46. The system of claim 45, wherein the first signal net comprises a first plurality of signal nets, and wherein the system further comprises means for applying the first identification means, the second identification means, the subset identification means, and the notification means to each of the first plurality of signal nets.

47. The system of claim 40, wherein the integrated circuit design comprises a computer-implemented model of an integrated circuit tangibly stored in a computer-readable medium.

48. The system of claim 40, wherein the first identification means comprises means for identifying the first signal net in a first layer of the integrated circuit design, and wherein the identified subset includes at least one signal net in a second layer of the integrated circuit design.

49. A computer-readable medium tangibly storing computer program instructions for performing steps of:

(A) identifying a first signal net in an integrated circuit design;

(B) identifying a plurality of second signal nets in the integrated circuit design;

(C) identifying a subset of the plurality of second signal nets that are closest to the first signal net by performing steps of;

(C)(1) sorting the plurality of second signal nets according to distances between the first signal net and the plurality of second signal nets to produce a sorted signal net list;

(C) (2) identifying a number NC; and

(C) (3) identifying the first NC signal nets in the sorted signal net list as the subset of the plurality of second signal nets; and

(D) notifying a user of the subset of the plurality of second signal nets.

50. The computer-readable medium of claim 49, wherein the computer program instructions for performing the step (A) comprise instructions for performing a step of:

(A)(1) identifying a first signal net being edited by the user using an integrated circuit design tool; and

wherein the computer program instructions for performing the step (D) comprise instructions for performing a step of;

(D) (1) notifying the user of the plurality of second signal nets while the user is editing the first signal net.

51. The computer-readable medium of claim 50, wherein the computer program instructions for performing the step (D) (1) comprise instructions for performing a step of providing to the user a visual indication of the at least one second signal net.

52. The computer-readable medium of claim 51, wherein the computer program instructions for performing the step (D) (1) comprise instructions for performing a step of providing to the user a visual indication of coordinates on the first signal net, which are closest to the subset of the plurality of second signal nets.

53. The computer-readable medium of claim 49, the first signal net comprises a first plurality of signal nets, and wherein the computer program instructions further comprise instructions for performing the steps (A), (B), (C), and (D) for each of the first plurality of signal nets.

54. The computer-readable medium of claim 49, wherein the computer program instructions for performing the step (D) comprise instructions for performing a step of generating a report identifying the first signal net and the subset of the plurality of second signal nets.

55. The computer-readable medium of claim 54, wherein the first signal net comprises a first plurality of signal nets, and wherein the computer program instructions further comprises instructions for performing the steps (A), (B), (C), and (D) for each of the first plurality of signal nets.

56. The computer-readable medium of claim 49, wherein the integrated circuit design comprises a computer-implemented model of an integrated circuit tangibly stored in a computer-readable medium.

57. The computer-readable medium of claim 49, wherein the computer program instructions for performing the step (A) comprise instructions for performing a step of identifying the first signal net in a first layer of the integrated circuit design, and wherein the subset identified in the step (C) includes at least one signal net in a second layer of the integrated circuit design.

58. A computer-implemented method comprising steps of:

(A) identifying a first signal net, in an integrated circuit design, being edited by a user using an integrated circuit design tool;

(B) identifying a second signal net in the integrated circuit design;

(C) determining whether at least one portion of the second signal net is within a threshold distance of the first signal net;

(D) if it is determined that at least one portion of the second signal net is within the threshold distance of the first signal net, measuring the aggregate length along the first signal net that is within the threshold distance of the second signal net;

(E) determining whether the measured length is at least as great as a threshold length; and

(F) notifying the user, while the user is editing the first signal net, that the second signal net is within the threshold distance of the first signal net if it is determined that the measured length is at least as great as the threshold length, by providing to the user a visual indication of coordinates on the first signal net which are within the threshold distance of the second signal net.

59. A computer-implemented system comprising:

first identification means for identifying a first signal net, in an integrated circuit design, being edited by a user using an integrated circuit design tool;

second identification means for identifying a second signal net in the integrated circuit design;

first determination means for determining whether at least one portion of the second signal net is within a threshold distance of the first signal net;

measurement means for measuring the aggregate length along the first signal net that is within the threshold distance of the second signal net if it is determined that at least one portion of the second signal net is within the threshold distance of the first signal net;

second determination means for determining whether the measured length is at least as great as a threshold length; and

notification means for notifying the user, while the user is editing the first signal net, that the second signal net is within the threshold distance of the first signal net if it is determined that the measured length is at least as great as the threshold length, by providing to the user a visual indication of coordinates on the first signal net which are within the threshold distance of the second signal net.

60. A computer-readable medium tangibly embodying computer program instructions for performing steps of:

(A) identifying a first signal net, in an integrated circuit design, being edited by a user using an integrated circuit design tool;

(B) identifying a second signal net in the integrated circuit design;

(C) determining whether at least one portion of the second signal net is within a threshold distance of the first signal net;

(D) if it is determined that at least one portion of the second signal net is within the threshold distance of the first signal net, measuring the aggregate length along the first signal net that is within the threshold distance of the second signal net;

(E) determining whether the measured length is at least as great as a threshold length; and

(F) notifying the user, while the user is editing the first signal net, that the second signal net is within the threshold distance of the first signal net if it is determined that the measured length is at least as great as the threshold length, by providing to the user a visual indication of coordinates on the first signal net which are within the threshold distance of the second signal net.

61. A computer-implemented method comprising steps of:

(A) identifying a first signal net, in an integrated circuit design, being edited by a user using an integrated circuit design tool;

(B) identifying a plurality of second signal nets in the integrated circuit design;

(C) identifying a subset of the plurality of second signal nets that are closest to the first signal net; and

(D) notifying the user of the subset of the plurality of second signal nets while the user is editing the first signal net, by providing to the user a visual indication of coordinates on the first signal net which are closest to the subset of the plurality of second signal nets.

62. A computer-implemented method comprising steps of:

(A) identifying a first signal net in a first layer of an integrated circuit design;

(B) identifying a plurality of second signal nets in the integrated circuit design;

(C) identifying a subset of the plurality of second signal nets that are closest to the first signal net, the subset of the plurality of second signal nets including at least one signal net in a second layer of the integrated circuit design; and

(D) notifying a user of the subset of the plurality of second signal nets.

63. A computer-implemented system comprising:

first identification means for identifying a first signal net, in an integrated circuit design, being edited by a user using an integrated circuit design tool;

second identification means for identifying a plurality of second signal nets in the integrated circuit design;

subset identification means for identifying a subset of the plurality of second signal nets that are closest to the first signal net; and

notification means for notifying a user of the subset of the plurality of second signal nets while the user is editing the first signal net, by providing to the user a visual indication of coordinates on the first signal net which are closest to the subset of the plurality of second signal nets.

64. A computer-implemented system comprising:

first identification means for identifying a first signal net in a first layer of an integrated circuit design;

second identification means for identifying a plurality of second signal nets in the integrated circuit design;

subset identification means for identifying a subset of the plurality of second signal nets that are closest to the first signal net, the subset of the plurality of second signal nets including at least one signal net in a second layer of the integrated circuit design; and

notification means for notifying a user of the subset of the plurality of second signal nets.

65. A computer-readable medium tangibly storing computer program instructions for performing steps of:

(A) identifying a first signal net, in an integrated circuit design, being edited by a user using an integrated circuit design tool;

(B) identifying a plurality of second signal nets in the integrated circuit design;

(C) identifying a subset of the plurality of second signal nets that are closest to the first signal net; and

(D) notifying the user of the subset of the plurality of second signal nets while the user is editing the first signal net, by providing to the user a visual indication of coordinates on the first signal net which are closest to the subset of the plurality of second signal nets.

66. A computer-readable medium tangibly storing computer program instructions for performing steps of:

(A) identifying a first signal net in a first layer of an integrated circuit design;

(B) identifying a plurality of second signal nets in the integrated circuit design;

(C) identifying a subset of the plurality of second signal nets that are closest to the first signal net, the subset of the plurality of second signal nets including at least one signal, net in a second layer of the integrated circuit design; and

(D) notifying a user of the subset of the plurality of second signal nets.