BIST Usage at the Board Level Survey Results

1. BIST Usage at the Board Level Survey Results Zoe Conroy, James Grealish, Harrison Miles, Hui Li, 7/14/2010

2. Outline of the Presentation • What is iNEMI’s BIST Project? • BIST survey objectives • Survey Respondents and Question Categories • Survey Questions and Results • Conclusions

3. What is iNEMI’s BIST Project? • The project was organized under the Board and Systems Manufacturing Test Technology Integration Group (TIG). • The project goals are to: • Promote wider use of component BIST at board level testing. • Investigate BIST tests that enable PCBA testing without or with a minimal use of In Circuit Test (ICT). • Promote the adoption of existing related standards for BIST design and test for use at the board level, or advise for new standards.

4. What is iNEMI? • iNEMI (International Electronic Manufacturing Initiative) is an industry-led consortium of approx. 65 electronics manufacturers, suppliers, industry associations, government agencies and universities. • It provides a place member companies collectively anticipate future technology and business needs and develop responses to meet those needs. • Other related iNEMI projects: • Boundary Scan Survey (Steve Butkovich - Cisco/Phil Geiger - Dell) • Board Functional Test Coverage (Tony Taylor – Intel)

5. iNEMI BIST Project - Team

6. Objective of the Survey • The industry survey is phase 1 of the BIST project. • The objective of the survey was to get baseline information to drive the project goals. • Gauge how much component BIST is currently run at board level test. • Find out if there are any roadblocks to be able to run it at board level. • Evaluate how useful it is for board level test. • Get information on its use in the future, for board level test. • Gather data on the use of existing standards and what else needs to be standardized.

7. Survey Respondents • Survey focused on two groups: • Board/System End Users of BIST (EU) • Board Design and Test Engineers/Managers • System Application Engineers • System Architects • Contract Manufacturing Engineers • Field Service and support Engineers • Integrated Circuit Engineering (IC) • IC Design and Test Engineers/Managers • IC Test Equipment Providers • EDA software tool providers

8. Survey Question Sections • Three question sections: • Company info, respondent area of responsibility • Two paths of questions • One for the End Users (EU) • One for the IC design and test (IC) • Any respondent received a maximum of 23 questions covering the survey objectives. • 20 questions were same for EU and IC.

9. Survey Question Categories • The 23 questions were divided up into the following sections: • Respondent Demographics • BIST availability and access • BIST usage in board and system test, BIST coverage • Future of BIST

10. SECTION 1Respondent Demographics

11. Survey Results – Respondent Statistics • BIST Survey released Dec 22nd `09, closed Jan 19th `10. • 202 respondents started, 140 completed it Product Sector Primary Business

12. Survey Results – Respondent Statistics

13. SECTION 2BIST availability and access

14. Types of IC BIST Used • Gives an indication of IC BIST availability (at the component level)

15. IC BIST Tests Available at the Board Level • Gives an indication of IC BIST availability at the board level • Of the BIST available (previous slide), this is how much that can be run at the board level • Generally high availability • EU more optimistic about the usability of IC BIST for board test

16. Who Provides BIST IP for Respondent's Company • Determines where the BIST IP is developed • BIST is mostly designed in-house • But commercial and 3rd party frequently used • If it’s in-house, is it more likely to be proprietary?

17. Are BIST Tests (IP) Proprietary? • IP protection impacts the availability of BIST and documentation. • The results are that: • Most BIST are proprietary • Tools and use models will need to protect the IP

18. Providing Documentation to Customers on Running BIST • Is lack of good documentation preventing BIST adoption? • Most documentation is proprietary to some degree • Tools and use models will need to protect the documentation

19. IC BIST Design & Implementation Consistency Across Products? • Inconsistency in BIST implementations can drive a major adoption effort for board test. • IC and EU disagree on consistency • Inconsistency driven by customization, features, access, lack of standards, etc.

20. BIST access within the IC • Comprehend how the IC BIST is accessed on the board, what is the most popular method and does it lead to standardization. • The survey results show that: • TAP access is generally available • Other access methods are used with TAP access

21. If BIST is run at the board, is the access level the same for IC & Board? • Need to know if different access mechanisms are required for board test, again for standardization. • Majority of respondents replied access is the same. • Although, some different access mechanisms will be required at the board level.

22. Are board designers requesting access to IC BIST? • Find out if board designers are requesting BIST from IC design and test, so they can use it at the board level. • Conclusion is that Board designers are requesting BIST > 60% of the time. • Most requested are Memory, Logic and PRBS/IOBIST.

23. SECTION 3BIST usage in board and system test

24. Percentage of PCBAs estimated to have IC BIST that is used at the board level • Major take away is many respondents “Do not know”. • However, End Users requesting BIST and majority of IC designers and test engineers say > 60% boards use BIST. Note: A prior question asked was “Are end users requesting BIST?” The survey divided after that into 2 paths: End users requesting BIST and End Users not requesting BIST . The separate answers are presented here.

25. Reasons IC BIST is currently run at the board/system level and its use in the future Green = End User Blue = IC • Current reasons: • Mfg test time and cost • Simplifies test environment • Provides at speed testing • Design validation • Resolves test access issue for high density PCBAs • Would like to use more for: • Programming to meet various test requirements • Coverage for board and system defects • Debugging the defect more effectively • Yield improvement • Reasons for future use: • Reuse in field for maintenance and debug • Resolve problems of signal integrity • Measure performance

26. Types of IC BIST that are currently run at Product Board and System Test • Many types of IC BIST are currently run at board level test. • Most common are internal memory BIST and high speed IO BIST

27. Effectiveness of BIST in detecting types of defects at the board level? • Both respondent groups agree closely that BIST tests are good at detecting defects at the board level. • Internal memory defect detection is most effective • Some IC designers and End Users do not know about the effectiveness of IC BIST for detecting external memory board level defects. IC designers and test End Users

28. Currently used Would like to use Don't know Currently used Would like to use Don't know IC designers and test End Users PCBA FT (functional test) PCBA FT (functional test) IC prototype tests and others) IC prototype tests and others) Product development debug Product development debug Product system test Product system test PCBA ICT (in - circuit test) PCBA ICT (in - circuit test) PCBA repair test PCBA repair test In - field maintenance/diagnostic test In - field maintenance/diagnostic test Product environmental test Product environmental test Other area(s) Other area(s) 0 10 20 30 0 10 20 30 40 50 Test steps where IC BIST is currently used and where respondents would like it to be used • Currently use: • IC group has strong preference for chip oriented development support activities • EU group has strong preference for IC BIST supporting PCBA functional test. • Would like to use: • Both groups agree that IC BIST is needed to address In-field maintenance/diagnostic testing • IC would like to use BIST more for product system test • EU would also like to use it more for PCBA repair test

29. Problems encountered running IC BIST tests at the board and system level • Biggest problem is BISTs are not supported by a standard • End users requesting BIST say “few ICs support BIST function”.

30. The estimated defect coverage goals at board test steps where BIST is currently used • Traditional Testing Coverage • Currently, > 80% coverage goal with traditional ICT and functional testing (no BIST). • Current BIST Coverage • Currently BIST coverage for most is > 20% at board level test steps. • Future BIST coverage • Majority would like future BIST coverage to be >80% at board level test steps.

31. Desired Coverage Goal Revelations

32. SECTION 4Future of BIST

33. How critical are board and system level BIST access for future coverage and fault isolation? • The results track between the EU and IC groups , where both groups think BIST access is critical.

34. Do respondents see IC BIST coupled with boundary-scan replacing some of the diminishing test point access of in-circuit testing for assembly defects? • The consensus in both groups is “yes” • Explanations from the EU group, who replied ”In some cases”: • Yes , if you count P1149.81 as "BIST“. • Boundary scan yes; BIST probably not • It will reduce functional test burden, but since BIST usually provides ~ 75% confidence, other functional tests will still be needed to ensure entire board works at speed when functions are used concurrently. • Protocols are sometimes difficult to implement in IEEE1149.1 • Explanation from the IC group: • On Nets that IC BIST can test, typically bus nets

35. In the next 2-5 years, what role will IC BIST play in your company’s product test? • Again both groups track, with “It will increase” being a significant majority of the answers. • Neither group thinks it will decrease.

36. If you have looked at or are looking at standards, specify which one(s). • There is about equal interest in both groups in 1149.7 and P1687. • More EUs are interested in P1581 than ICs. • “Other” comments from the EUs: • Definitely interested in P1581, P1687, but not 1149.7 is not attractive at all. • Involved with P1581. Not sure it will ever be a standard. • SJTAG (not yet submitted a PAR to IEEE). • IEEE 1149.1 (new revision will address enhancements for future use). • 1149.6, 1500 • P1532. • Maybe SJTAG as an access methodology. 1581 may be used, but we aren't actively driving it. • “Other” comment on the IC side was: “P1149.8.1”.

37. If standards are established on IC BIST design and its application in board and system level test, what do you think should be standardized? • Areas of equivalent concern: • BIST description language and files. • Interface to instruments and ATE. • Significant deltas: • EUs (88%) are more concerned about access interface and method than ICs (66%). • EUs (76%) are more concerned about interface compatibility between chips than ICs (46%) • EUs (60%) are somewhat more concerned about BIST instructions then ICs (43%). • The two “other” responses from EU: • “The supporting languages should be simple and concise” • “Treat BIST as Embedded Instrument, and use P1687 to conduct testing”

38. “Explain HOW BIST tests should be standardized”

39. “Explain HOW BIST tests should be standardized”

40. Conclusions • Many IC BIST tests are available and currently run at the board level. • Internal & external memory testing, V & T monitoring, IOBIST, Logic BIST are the most common. • 60% Board designers are requesting access to IC BIST. • Access method to the BIST tests is suitable for Mfg test: • Predominantly access is via 1149.1 TAP. • The majority of BIST tests are proprietary, • This could present a roadblock to wider adoption and implementation at the board test level. • BIST run at the board/system level is good at catching defects in these areas: • Internal memory cell, IO interconnect, high speed IO and logic BIST • It is currently run at many different board and system test steps, • A future use is to run more BIST during in- field maintenance and diagnostics and PCBA repair test.

41. Conclusions • There are however still some problems encountered: • few ICs support BIST function, • commercial IC supplier do not give the BIST function to the board users, • lack of access when it is mounted on the board, • BIST is not supported by a standard. • Looking to the future: • It is seen to be critical for future fault isolation, • Respondents would like BIST coverage to be > 80% at the board level testing, • More than 75% of respondents see IC BIST coupled with boundary-scan replacing some of the diminishing test point access of in-circuit testing for assembly defects, • Well over 50% of respondents have definite plans to adopt current standards or are actively involved and considering adopting them.

42. Next Steps Considered for Phase 2 • The usefulness of BIST at board and system level can continue to be promoted. • The team needs to look at how existing standards can help with BIST standardization and implementation. • Promotion of these existing standards for the BIST implementation. • Any gaps found in the existing standards will be presented to the respective standards committee. • Standardizing description languages and interfaces should be investigated. • The use of BIST to help with ICT lack of coverage needs further research.

44. Boundary-Scan Standards and Initiatives (Released & WIP)