Noise checking method and apparatus and computer-readable recording medium which records a noise checking program

• US 7,158,920 B2
• Filed: 11/03/2004
• Issued: 01/02/2007
• Est. Priority Date: 06/17/2004
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ishikawa, Yoichiro
• Primary Examiner(s): Tsai; Carol S. W.
• Application Number:
  US10/979,117
• Publication Number:
  US 20050283668A1
• Time in Patent Office: 790 Days
• Field of Search: 702/691, 702/74, 702/75, 702/76, 702/79, 702/182, 702/191
• US Class Current: 702/191
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

The apparatus reduces the amount of correction for noise value error, so as to reduce work needed for correction to ensure error avoidance, and to improve the freedom of layout design, and to reduce load on DA. Based on a timing chart of signal transfer on each wire, the last edge appearance timing in the signal waveform of a victim whose noise value exceeds a limit value is compared with the last edge appearance timing in the signal waveform of an aggressor, to evaluate the noise value error in the victim. The apparatus is used in static noise checking of cell arrangement and inter-cell wiring after such cell arrangement and inter-cell wiring are performed at design of integrated circuits such as LSIs.

Claims

1. A noise checking method for performing, after carrying out cell arrangement and inter cell wiring in an integrated circuit, static noise checking on a result of the cell arrangement and the inter-cell wiring, said method comprising:

a timing analyzing step, in which a timing chart of signal transfer on each wire is obtained by performing delay simulation with timing analysis based on the result of the cell arrangement and the inter-cell wiring;

a noise value calculating step, in which a noise value is calculated, said noise value representing a degree at which at least one affecting wire (hereinafter will be called the “

aggressor”

), running in parallel with an object wire (hereinafter will be called the “

victim”

) to be checked, induces noise onto the victim;

a noise value evaluating step, in which it is evaluated whether or not the noise value calculated at said noise value calculating step exceeds a limit value; and

an error evaluating step, in which, if it is evaluated at said noise value evaluating step that the noise value is greater than the limit value, comparison is performed, based on the timing chart obtained at said timing analyzing step, between a last edge appearance timing in a signal waveform transmitted on the victim and a last edge appearance timing in a signal waveform transmitted on the aggressor, and then a decision is made on a noise value error in the victim based on the comparison result.

5. A noise checking method as set forth in claim 1, wherein, at said error evaluating step, if the last edge appearance timing in the signal waveform transmitted on the aggressor is later than the last edge appearance timing in the signal waveform transmitted on the victim, it is evaluated that a noise error occurs in the victim.

7. A noise checking method as set forth in claim 1,

wherein at said timing analyzing step, a slack value, which is a timing margin of a driver of the victim, is calculated by the delay simulation, and

wherein at said error evaluating step, if the last edge appearance timing in the signal waveform transmitted on the aggressor is later than a timing which is obtained by adding the slack value to the last edge appearance timing of the signal waveform transmitted on the victim, it is evaluated that a noise value error occurs in the victim.

2. A noise checking method for performing, after carrying out cell arrangement and inter cell wiring in an integrated circuit, a static noise checking on a result of the cell arrangement and the inter-cell wiring, said method comprising:

a timing analyzing step, in which a timing chart of signal transfer on each wire is obtained by performing delay simulation with timing analysis based on the result of the cell arrangement and the inter-cell wiring;

a one-to-one noise value calculating step, in which a one-to-one noise value is calculated, said one-to-one noise value representing a degree at which one affecting wire (hereinafter will be called the “

aggressor”

), running in parallel with an object wire (hereinafter will be called the “

victim”

) to be checked, induces noise onto the victim;

a one-to-one noise value evaluating step, in which it is evaluated whether or not the one-to-one noise value, calculated at said one-to-one noise value calculating step, exceeds a first limit value;

a one-to-n noise value calculating step, in which, if it is evaluated at said one-to-one noise value evaluating step that the one-to-one noise value does not exceed the first limit value, a one-to-n noise value is calculated, said one-to-n noise value representing a degree at which n (n is a natural number equal to or greater than

     2) aggressors, running in parallel with the victim, induces noise onto the victim;

a one-to-n noise value evaluating step, in which it is evaluated whether or not the one-to-n noise value, calculated at said one-to-n noise value calculating step, exceeds a second limit value; and

a first error evaluating step, in which, if it is evaluated at said one-to-n noise value evaluating step that the one-to-n noise value exceeds the second limit value, comparison is performed, based on the timing chart obtained at said timing analyzing step, between a last edge appearance timing in a signal waveform transmitted on the victim and last edge appearance timings in signal waveforms transmitted on the n aggressors, and then a decision is made on a noise value error in the victim based on the comparison result.

3. A noise checking method as set forth in claim 2, further comprising:

a permissible upper limit value evaluating step, in which, if it is evaluated at said one-to-one noise value evaluating step that the one-to-one noise value exceeds the first limit value, it is then evaluated whether or not the one-to-one noise value of the victim exceeds a permissible upper limit value which is obtained by adding a specific permissible value to the first limit value; and

a second error evaluating step, in which, if it is evaluated at said permissible upper limit evaluating step that the one-to-one noise value does not exceed the permissible upper limit, comparison is performed, based on the timing chart obtained at said timing analyzing step, between a last edge appearance timing in a signal waveform transmitted on the victim and a last edge appearance timing in a signal waveform transmitted on the one aggressor, and then a decision is made on a noise value error in the victim based on the comparison result,

if it is evaluated at said second error evaluating step that no noise value error occurs in the victim, the method proceeding to said one-to-n noise value calculating step, said one-to-n noise value evaluating step, and said first error evaluating step.

4. A noise checking method as set forth in claim 2, wherein at said first error evaluating step, when the comparison is performed between the last edge appearance timing in the signal waveform transmitted on the victim and last edge appearance timings in the signal waveforms transmitted on the n aggressors, the signal waveforms of the n aggressors are synthesized, and comparison is made between a last edge appearance timing of the synthesized signal waveform and the last edge appearance timing of the waveform transmitted on the victim.

6. A noise checking method as set forth in claim 2, wherein, at said first error evaluating step, if the last edge appearance timing in the signal waveform transmitted on at least one of the n aggressors is later than the last edge appearance timing in the signal waveform transmitted on the victim, it is evaluated that a noise error occurs in the victim.

8. A noise checking method as set forth in claim 2,

wherein at said timing analyzing step, a slack value, which is a timing margin of a driver of the victim, is calculated by the delay simulation, and

wherein at said first error evaluating step, if the last edge appearance timing in the signal waveform transmitted on at least one of the n aggressors is later than a timing which is obtained by adding the slack value to the last edge appearance timing of the signal waveform transmitted on the victim, it is evaluated that a noise value error occurs in the victim.

9. A noise checking apparatus for performing, after carrying out cell arrangement and inter cell wiring in an integrated circuit, static noise checking on a result of the cell arrangement and the inter-cell wiring, said apparatus comprising:

a timing analyzing unit, in which a timing chart of signal transfer on each wire is obtained by performing delay simulation with timing analysis based on the result of the cell arrangement and the inter-cell wiring;

a noise value calculating unit, in which a noise value is calculated, said noise value representing a degree at which at least one affecting wire (hereinafter will be called the “

aggressor”

), running in parallel with an object wire (hereinafter will be called the “

victim”

) to be checked, induces noise onto the victim;

a noise value evaluating unit, in which it is evaluated whether or not the noise value calculated by said noise value calculating unit exceeds a limit value; and

an error evaluating unit, in which, if it is evaluated by said noise value evaluating unit that the noise value is greater than the limit value, comparison is performed, based on the timing chart obtained by said timing analyzing unit, between a last edge appearance timing in a signal waveform transmitted on the victim and a last edge appearance timing in a signal waveform transmitted on the aggressor, and then a decision is made on a noise value error in the victim based on the comparison result.

13. A noise checking apparatus as set forth in claim 9, wherein at said error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on the aggressor is later than the last edge appearance timing in the signal waveform transmitted on the victim, it is evaluated that a noise error occurs in the victim.

15. A noise checking apparatus as set forth in claim 9,

wherein at said timing analyzing unit, a slack value, which is a timing margin of a driver of the victim, is calculated by the delay simulation, and

wherein at said error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on the aggressor is later than a timing which is obtained by adding the slack value to the last edge appearance timing of the signal waveform transmitted on the victim, it is evaluated that a noise value error occurs in the victim.

10. A noise checking apparatus for performing, after carrying out cell arrangement and inter cell wiring in an integrated circuit, static noise checking on a result of the cell arrangement and the inter-cell wiring, said apparatus comprising:

a timing analyzing unit, in which a timing chart of signal transfer on each wire is obtained by performing delay simulation with timing analysis based on the result of the cell arrangement and the inter-cell wiring;

a one-to-one noise value calculating unit, in which a one-to-one noise value is calculated, said one-to-one noise value representing a degree at which one affecting wire (hereinafter will be called the “

aggressor”

), running in parallel with an object wire (hereinafter will be called the “

victim”

) to be checked, induces noise onto the victim;

a one-to-one noise value evaluating unit, in which it is evaluated whether or not the one-to-one noise value, calculated by said one-to-one noise value calculating unit, exceeds a first limit value;

a one-to-n noise value calculating unit, in which, if it is evaluated by said one-to-one noise value evaluating unit that the one-to-one noise value does not exceed the first limit value, a one-to-n noise value is calculated, said one-to-n noise value representing a degree at which n (n is a natural number equal to or greater than

     2) aggressors, running in parallel with the victim, induces noise onto the victim;

a one-to-n noise value evaluating unit, in which it is evaluated whether or not the one-to-n noise value, calculated by said one-to-n noise value calculating unit, exceeds a second limit value; and

a first error evaluating unit, in which, if it is evaluated by said one-to-n noise value evaluating unit that the one-to-n noise value exceeds the second limit value, comparison is performed, based on the timing chart obtained by said timing analyzing unit, between a last edge appearance timing in a signal waveform transmitted on the victim and last edge appearance timings in signal waveforms transmitted on the n aggressors, and then a decision is made on a noise value error in the victim based on the comparison result.

11. A noise checking apparatus as set forth in claim 10, further comprising:

a permissible upper limit value evaluating unit, in which, if it is evaluated by said one-to-one noise value evaluating unit that the one-to-one noise value exceeds the first limit value, it is then evaluated whether or not the one-to-one noise value of the victim exceeds a permissible upper limit value which is obtained by adding a specific permissible value to the first limit value; and

a second error evaluating unit, in which, if it is evaluated at said permissible upper limit evaluating step that the one-to-one noise value does not exceed the permissible upper limit, comparison is performed, based on the timing chart obtained by said timing analyzing unit, between a last edge appearance timing in a signal waveform transmitted on the victim and a last edge appearance timing in a signal waveform transmitted on the one aggressor, and then a decision is made on a noise value error in the victim based on the comparison result,

if it is evaluated by said second error evaluating unit that no noise value error occurs in the victim, the process proceeding to the process performed by said one-to-n noise value calculating unit, said one-to-n noise value evaluating unit, and said first error evaluating unit.

12. A noise checking apparatus as set forth in claim 10, wherein at said first error evaluating unit, when the comparison is performed between the last edge appearance timing in the signal waveform transmitted on the victim and last edge appearance timings in the signal waveforms transmitted on the n aggressors, the signal waveforms of the n aggressors are synthesized, and comparison is made between a last edge appearance timing of the synthesized signal waveform and the last edge appearance timing of the waveform transmitted on the victim.

14. A noise checking apparatus as set forth in claim 10, wherein at said first error evaluating step, if the last edge appearance timing in the signal waveform transmitted on at least one of the n aggressors is later than the last edge appearance timing in the signal waveform transmitted on the victim, it is evaluated that a noise error occurs in the victim.

16. A noise checking apparatus as set forth in claim 10,

wherein at said timing analyzing unit, a slack value, which is a timing margin of a driver of the victim, is calculated by the delay simulation, and

wherein at said first error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on at least one of the n aggressors is later than a timing which is obtained by adding the slack value to the last edge appearance timing of the signal waveform transmitted on the victim, it is evaluated that a noise value error occurs in the victim.

17. A computer-readable recording medium in which is recorded a noise checking program for a computer to function as a noise checking apparatus for performing, after carrying out cell arrangement and inter cell wiring in an integrated circuit, static noise checking on a result of the cell arrangement and the inter-cell wiring, said program instructing the computer to function as the following:

a timing analyzing unit, in which a timing chart of signal transfer on each wire is obtained by performing delay simulation with timing analysis based on the result of the cell arrangement and the inter-cell wiring;

a noise value calculating unit, in which a noise value is calculated, said noise value representing a degree at which at least one affecting wire (hereinafter will be called the “

aggressor”

), running in parallel with an object wire (hereinafter will be called the “

victim”

) to be checked, induces noise onto the victim;

a noise value evaluating unit, in which it is evaluated whether or not the noise value calculated by said noise value calculating unit exceeds a limit value; and

an error evaluating unit, in which, if it is evaluated at said noise value evaluating step that the noise value is greater than the limit value, comparison is performed, based on the timing chart obtained by said timing analyzing unit between a last edge appearance timing in a signal waveform transmitted on the victim and a last edge appearance timing in a signal waveform transmitted on the aggressor, and then a decision is made on a noise value error in the victim based on the comparison result.

21. A computer-readable recording medium as set forth in claim 17, wherein when said noise checking program instructs the computer to function as the error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on the aggressor is later than the last edge appearance timing in the signal waveform transmitted on the victim, it is evaluated that a noise error occurs in the victim.

23. A computer-readable recording medium as set forth in claim 17,

wherein when said noise checking program instructing the computer to function as said timing analyzing unit, a slack value, which is a timing margin of a driver of the victim, is calculated by the delay simulation, and

wherein when said noise checking program instructing the computer to function as said error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on the aggressor is later than a timing which is obtained by adding the slack value to the last edge appearance timing of the signal waveform transmitted on the victim, it is evaluated that a noise value error occurs in the victim.

18. A computer-readable recording medium in which is recorded a noise checking program for a computer to function as a noise checking apparatus for performing, after carrying out cell arrangement and inter cell wiring in an integrated circuit, static noise checking on a result of the cell arrangement and the inter-cell wiring, said program instructing the computer to function as the following:

a timing analyzing unit, in which a timing chart of signal transfer on each wire is obtained by performing delay simulation with timing analysis based on the result of the cell arrangement and the inter-cell wiring;

a one-to-one noise value calculating unit, in which a one-to-one noise value is calculated, said one-to-one noise value representing a degree at which one affecting wire (hereinafter will be called the “

aggressor”

), running in parallel with an object wire (hereinafter will be called the “

victim”

) to be checked, induces noise onto the victim;

a one-to-one noise value evaluating unit, in which it is evaluated whether or not the one-to-one noise value, calculated by said one-to-one noise value calculating unit, exceeds a first limit value;

a one-to-n noise value calculating unit, in which, if it is evaluated by said one-to-one noise value evaluating unit that the one-to-one noise value does not exceed the first limit value, a one-to-n noise value is calculated, said one-to-n noise value representing a degree at which n (n is a natural number equal to or greater than

     2) aggressors, running in parallel with the victim, induces noise onto the victim;

a one-to-n noise value evaluating unit, in which it is evaluated whether or not the one-to-n noise value, calculated by said one-to-n noise value calculating unit, exceeds a second limit value; and

a first error evaluating unit, in which, if it is evaluated by said one-to-n noise value evaluating unit that the one-to-n noise value exceeds the second limit value, comparison is performed, based on the timing chart obtained by said timing analysis unit, between a last edge appearance timing in a signal waveform transmitted on the victim and last edge appearance timings in signal waveforms transmitted on the n aggressors, and then a decision is made on a noise value error in the victim based on the comparison result.

19. A computer-readable recording medium as set forth in claim 18, said noise checking program further instructing the computer to function as:

a permissible upper limit value evaluating unit, in which, if it is evaluated by said one-to-one noise value evaluating unit that the one-to-one noise value exceeds the first limit value, it is then evaluated whether or not the one-to-one noise value of the victim exceeds a permissible upper limit value which is obtained by adding a specific permissible value to the first limit value; and

a second error evaluating unit, in which, if it is evaluated at said permissible upper limit evaluating step that the one-to-one noise value does not exceed the permissible upper limit, comparison is performed, based on the timing chart obtained by said timing analyzing unit, between a last edge appearance timing in a signal waveform transmitted on the victim and a last edge appearance timing in a signal waveform transmitted on the one aggressor, and then a decision is made on a noise value error in the victim based on the comparison result,

if it is evaluated by said second error evaluating unit that no noise value error occurs in the victim, the noise checking program instructing the computer to carry out the process performed by said one-to-n noise value calculating unit, said one-to-n noise value evaluating unit, and said first error evaluating unit.

20. A computer-readable recording medium as set forth in claim 18, said noise checking program instructing the computer to function as the first error evaluating unit, wherein when the comparison is performed between the last edge appearance timing in the signal waveform transmitted on the victim and last edge appearance timings in the signal waveforms transmitted on the n aggressors, the signal waveforms of the n aggressors are synthesized, and comparison is made between a last edge appearance timing of the synthesized signal waveform and the last edge appearance timing of the waveform transmitted on the victim.

22. A computer-readable recording medium as set forth in claim 18, wherein when said noise checking program instructs the computer to function as the first error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on at least one of the n aggressors is later than the last edge appearance timing in the signal waveform transmitted on the victim, it is evaluated that a noise error occurs in the victim.

24. A computer-readable recording medium as set forth in claim 18,

wherein when said noise checking program instructing the computer to function as said timing analyzing unit, a slack value, which is a timing margin of a driver of the victim, is calculated by the delay simulation, and

wherein when said noise checking program instructing the computer to function as said first error evaluating unit, if the last edge appearance timing in the signal waveform transmitted on at least one of the n aggressors is later than a timing which is obtained by adding the slack value to the last edge appearance timing of the signal waveform transmitted on the victim, it is evaluated that a noise value error occurs in the victim.