Method and apparatus for increased effectiveness of delay and transition fault testing

• US 8,381,050 B2
• Filed: 11/25/2009
• Issued: 02/19/2013
• Est. Priority Date: 11/25/2009
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Gillis, Pamela S., Smith, Jack R., Wilder, Tad J., Woytowich, Francis, Xia, Tian
• Primary Examiner(s): BRITT, CYNTHIA H
• Application Number:
  US12/625,703
• Publication Number:
  US 20110121838A1
• Time in Patent Office: 1,182 Days
• Field of Search: 714/724, 714/726, 714/731, 714/741, 714/744
• US Class Current: 714/731
• CPC Class Codes: G01R 31/318544 Scanning methods, algorithms and patterns G01R31/3183 takes precedence
• CPC Class Codes: G01R 31/318552 Clock circuits details
• CPC Class Codes: G01R 31/318594 Timing aspects clock circuits G01R31/318552
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew

Abstract

The invention disclosed herein provides increased effectiveness of delay and transition fault testing. The method of delay fault testing integrated circuits comprises the steps of creating a plurality of test clock gating groups. The plurality of test clock gating groups comprising elements defining inter-element signal paths within the integrated circuit. Each of the elements of the plurality of test clock gating groups share clock frequency and additional shared characteristics. At least one test signal is commonly and selectively connected through at least one low-speed gate transistor to each of the elements comprising each of the plurality of test clock gating groups based on membership in the test clock gating group. This invention can also be practiced using scan-enable gating groups for the same purposes.

Claims

1. A method of delay fault testing an integrated circuit comprising:

creating a plurality of test clock gating groups, said plurality of test clock gating groups comprising elements defining signal paths between components within said integrated circuit, each of said elements of said plurality of test clock gating groups sharing clock frequency and at least one additional shared characteristic; and

selectively connecting at least one test signal through at least one low-speed gate transistor to each of said elements comprising said plurality of test clock gating groups based on membership in said test clock gating group, all members of each test clock gating group being connected to a common test signal.

2. The method of claim 1, said at least one additional shared characteristic comprising at least one of:

latency, skew and cross-domain signal paths.

3. The method of claim 1, at least one of said elements of said integrated circuit being based on a plurality of pre-designed cores and said connecting of at least one test signal to at least one of said plurality of pre-designed cores being enabled with a single gate.

4. The method of claim 1, at least two of said elements being slow logic elements selectively enabled by a single gate.

5. The method of claim 1, at least two of said elements being multi-cycle elements selectively enabled by a single gate.

6. The method of claim 1, further comprising:

programming an on-chip programmable delay line for a launch time of at least one pattern generator, said launch time being based on a simulation of delays in said signal paths and a tap selection of said on-chip programmable delay line;

generating a test pattern based on said launch time; and

indicating a result of a comparison between a test pattern received over said signal path to said test pattern generated based on said launch time.

7. The method of claim 6, at least one of said plurality of pre-designed cores being implemented using field programmable gate arrays.

8. The method of claim 6, further comprising verifying proper functioning of said programmable delay line based on the further steps of:

forming an oscillator loop with an output;

programming said on-chip delay line based on a second tap setting;

measuring an oscillating frequency at said output of said oscillator loop;

identifying an expected oscillating frequency based on said tap setting;

comparing said oscillating frequency measured at said output of said oscillator loop to said expected oscillating frequency;

indicating a proper functioning of said programmable delay line based on said comparing.

9. The method of claim 1, further comprising:

programming an on-chip programmable delay line to create a high precision test clock for a launch time of at least one pattern generator, said launch time based on an optimal tap selection of said on-chip programmable delay line based on a simulation of a routed design of said signal paths;

generating a test pattern based on said launch time; and

indicating a result of a comparison between a test pattern received over said signal path to said test pattern generated based on said launch time.

10. The method of claim 6, routing of said signal paths being maintained under test.

11. The method of claim 6, further comprising grouping said signal paths into a plurality of independent groups based on common elements and selecting paths from said plurality of independent groups enabling simultaneous testing.

12. A method of delay fault testing an integrated circuit comprising:

creating a plurality of scan-enable gating groups, said plurality of scan-enable gating groups comprising elements defining signal paths between components within said integrated circuit, each of said elements of said plurality of scan-enable gating groups sharing clock frequency and at least one additional shared characteristic; and

selectively connecting at least one test signal through at least one low-speed gate transistor to said elements comprising said plurality of scan-enable gating groups using low-speed gating and based on membership in said scan-enable gating group, all members of each scan-enable gating group being connected to a common test signal.

13. The method of claim 12, further comprising:

programming an on-chip programmable delay line for a launch time of at least one pattern generator, said launch time being based on a simulation of delays in said signal paths and a tap selection of said on-chip programmable delay line;

generating a test pattern based on said launch time; and

indicating a result of a comparison between a test pattern received over said signal path to said test pattern generated based on said launch time.

14. The method of claim 13, at least one of said plurality of pre-designed cores being implemented using field programmable gate arrays.

15. An integrated circuit structure comprising:

a plurality of scan-enable gating groups, said plurality of scan-enable gating groups comprising elements defining signal paths between components within said integrated circuit, each of said elements of said plurality of scan-enable gating groups sharing clock frequency and at least one additional shared characteristic; and

at least one low-speed gate transistor selectively connecting at least one test signal through to said elements;

said elements comprising said plurality of scan-enable gating groups;

said low speed gate transistor connected based on said elements membership in said scan-enable gating group, all members of each scan-enable gating group being connected to a common test signal.

16. The integrated circuit structure of claim 15, said at least one additional shared characteristic comprising at least one of:

latency, skew and cross-domain signal paths.

17. The integrated circuit structure of claim 15, at least one of said elements of said integrated circuit being based on a plurality of pre-designed cores and said gating of at least one test signal to at least one of said plurality of pre-designed cores being enabled with a single gate.

18. The integrated circuit structure of claim 15, at least two of said elements being slow logic elements selectively enabled by a single gate.

19. The integrated circuit structure of claim 15, at least two of said elements being multi-cycle elements selectively enabled by a single gate.

20. The integrated circuit structure of claim 15, further comprising:

at least one test pattern generator, said at least one test pattern generator generating a test pattern over at least one of said signal paths;

an on-chip programmable delay line for programming a delayed launch time for said test pattern, said launch time being based on delays predicted in said at least one signal paths, said delayed launch time being based on a tap selection of said on-chip programmable delay line; and

an output result analyzer that indicates a result of a comparison between a test signal received over at least one of said signal paths and said test pattern generated by said at least one test pattern generator.

21. The integrated circuit of claim 20, at least one of said plurality of pre-designed cores being implemented using field programmable gate arrays.

22. An integrated circuit with built-in self test structures comprising:

low speed gates for selectively gating at least one test signal to elements comprising a plurality of scan-enable gating groups, said scan-enable gating groups comprising elements defining signal paths between components of said integrated circuit and sharing clock frequency and at least one additional shared characteristic, all members of each scan-enable gating group being connected to a common test signal.

23. The integrated circuit with built-in self-test structures of claim 22, further comprising:

at least one test pattern generator, said at least one test pattern generator generating a test pattern over at least one of said signal paths;

an on-chip programmable delay line for programming a delayed launch time for said test pattern, said launch time being based on delays predicted in said at least one signal paths, said delayed launch time being based on a tap selection of said on-chip programmable delay line; and

an output result analyzer that indicates a result of a comparison between a test signal received over at least one of said signal paths and said test pattern generated by said at least one test pattern generator.

24. The integrated circuit of claim 23, at least one of said plurality of pre-designed cores being implemented using field programmable gate arrays.

25. A program storage device readable by machine tangibly embodying a program of instructions executable by said machine for performing a method of delay fault testing of an integrated circuit, said method comprising the steps of:

creating a plurality of test clock gating groups, said plurality of test clock gating groups comprising elements defining signal paths between components within said integrated circuit, each of said elements of said plurality of test clock gating groups sharing clock frequency and at least one additional shared characteristic; and

selectively connecting at least one test signal through at least one low-speed gate transistor to each of said elements comprising said plurality of test clock gating groups based on membership in said test clock gating group, all members of each test clock gating group being connected to a common test signal.