Current Time: 11:32 AM. Ken Ryan, Qualmark. LSP-Technology Pte Ltd

Transcription

1 2012 ARS, Asia-Pacific: Jakarta Session 11 Replacement Begins at 2:40 PM, Wednesday, October 17th Current Time: 11:32 AM Is Your Reliability Testing Program Keeping Pace with Manufacturing and Design Advancements? Ken Ryan, Qualmark &OhCh Chong Hoe, LSP-Technology Pte Ltd

2 Agenda Introduction Introduction to HALT 5 min 5 min HALT and HASS Why they work 5 min Benefits of HALT and HASS The HALT Process 10 min 10 min HASS theory and process 5 min HALT/HASS equipment equp e 5 min Summary Questions 5 min 10 min Slide Number: 2

3 ACRONYMS HALT Highly Accelerated Life Test HASS Highly Accelerated Stress Screen POS Proof of Screen RS Repetitive Shock (vibration) Slide Number: 3

4 Qualmark Support in Indonesia LSP- Technology Pte Ltd Competencies :. Environmental Test Chamber Repair, Start-up, Maintenance and Calibration Mechanical Test Repair, Start-up and Maintenance Sale and lease of Environmental Test Equipment and Mechanical Tester Pre-owned dchambers Test System integration Slide Number: 4

5 Improve Product Reliability and Profitability with HALT and HASS Slide Number: 5

6 Reliability Pressures Modern technology applied during design and manufacturing can introduce failure modes undetectable by conventional tests. Consumer demand, corporate mandates, shorter design cycles, litigation exposure, and escalating warranty costs create pressures to extend product reliability. HALT and HASS are rapidly being adopted as a solution to these challenges. Slide Number: 6

7 The Goal of HALT The goal of HALT is to rapidly fatigue a product, quickly forcing the weakest parts of the design to fail so the failure modes can be detected and corrected. This rapid fatigue is accomplished by applying thermal and vibration stresses of types and levels that are not normally seen in the field. Slide Number: 7

8 HALT Fundamentals HALT is not a test with a pass or fail result, it is a process tool for the development team. There are no pre-established limits - the product determines the limits. it Stress to failure. It is critical to monitor the product during stressing. Slide Number: 8

9 Different Purpose, Different Stresses Extreme Temperatures Extreme Temperature change rates 6 DOF RS vibration (6 Degree of Freedom, Repetitive Shock) Stimulate, Not Simulate Slide Number: 9

10 Slow Motion Video Example Slide Number: 10

11 How HALT Works Start t low and step up the stress, testing the product during the stressing Slide Number: 11

12 How HALT Works Gradually increase stress level until a failure occurs Slide Number: 12

13 How HALT Works Analyze the failure Slide Number: 13

14 How HALT Works Make temporary improvements Slide Number: 14

15 How HALT Works Increase stress and start process over Slide Number: 15

16 How HALT Works FUNDAMENTAL LIMIT OF TECHNOLOGY Slide Number: 16

17 Why HALT Works S vs N The power of HALT is derived from a simple basic principle if you wish to fatigue a component, you can stress it with lower levels of stress (S) for a lot of cycles (N), or use a higher level of stress for a fewer number of cycles. Slide Number: 17

18 Level of Stress vs. Cycles to Failure the Heart of HALT High stress/low cycle Low stress/high cycle Effectiveness and Economics Yardsticks for ESS Decisions, i Smithson, Stephen A., Proceedings Institute of Environmental Sciences, 1990 Slide Number: 18

19 PRODUCT STRENGTH Slide Number: 19 Applied Reliability Symp posium, Asia Pacific 2012

20 PRODUCT STRENGTH Nominal Product Strength Lower Limit of Strength Distribution Upper Limit of Strength Distribution Lower Strength Higher Strength Strength may be tolerance of temperature, vibration, humidity, time, etc., or a composite of all of the above Slide Number: 20

21 FIELD STRESSES Nominal Field Stresses Lower Stresses Higher Stresses Field stresses can include temperature, vibration, humidity, time, dust, shock, etc. Slide Number: 21

22 Product Strength Versus Field Stresses Field Stress Product Strength Weaker units fail under higher h field stresses Slide Number: 22

23 Product Strength Versus Field Stresses Field Stress Product Strength Product strength may deteriorate over time Weaker units fail under higher h field stresses Product strength deteriorates over time causing even more failures Slide Number: 23

24 Effect of Halt on Product Strength Before HALT Product strength curve narrower due to improving low margins After HALT Increase product strength Slide Number: 24

25 HALT Different from DVT Different Purpose, Different Results DVT Verifies that product meets specification Verifies that product will function in its intended environment Is successful when product shows no failures HALT Stresses product beyond specification Stresses product until weak points fail Determines functional and destruct limits Is successful when failure modes are found and eliminated Slide Number: 25

26 A KEY Difference... PASS FAIL DVT is a Pass/Fail test HALT is not - you can never PASS a HALT. There are no pre- established limits. Slide Number: 26

27 Failure Relationship Between Environmental Factors and Failure at Hughes Electronics Sand & Brine, 4% Other, 4% Dust, 6% Humidity, 18% Temperature, 40% Vibration, 28% Source: ESPEC Technology Report, 1996 Slide Number: 27

28 Should I Design to HALT Limits? Absolutely Not! Design for normal limits. Let HALT tell you where the weak links are. Use information found in HALT to eliminate the weak links ahead of time. Slide Number: 28

29 The Goal of HASS The goal of HASS is to rapidly fatigue all production units, using stresses based on the limits found in HALT. This forces any new weaknesses in the product to become detectable so that the defective units will not be shipped. These new weaknesses can be due to process, design, or supplier changes. The Proof of Screen (POS) process ensures that HASS will not reduce life of the product in the field and will find the desired failure modes. Slide Number: 29

30 HASS - Different From Burn-In Different Purpose, Different Results Burn-In Weed out infant mortality Verify function at elevated temp. HASS Verify that HALT limits haven t changed No new weak links due to process or component variability, including upstream suppliers Slide Number: 30

31 Proof of Screen (POS) - A Critical Step Serves two key ypurposesp Verify that the screen is not taking excessive life out of the product Verify that the screen is effectively finding defective units Slide Number: 31

32 The Equipment Needed d For HALT and HASS Slide Number: 32

33 HALT and HASS Equipment Liquid nitrogen cooled Rapid thermal transitions, greater than 60 C/min -100 C to +200 C (250 C) operating range Repetitive i shock vibration i 6 degrees of freedom 3 axis & 3 rotations, ti simultaneously Broad frequency band (10-5,000Hz) Combined environment Thermal and vibration Low ambient noise <73dbA Slide Number: 33

34 ED Shakers - NOT Suitable for HALT/HASS 6 DOF Repetitive Shock (RS) vibration stress is key to HALT ED not well suited to HALT and HASS applications Difficult to incorporate into a thermal system Single axis Expensive Typical ED Shakers Significant facilities requirements Coil and armature, similar to speaker technology Huge coils, huge amplifiers Very carefully controlled frequency and amplitude Slide Number: 34

35 What Is RS Vibration? Pneumatically operated piston-style actuators (lubricant-free are best) Semi-rigid vibration table Table supported on springs Slide Number: 35

36 HALT s Repetitive Shock Vibration Multi-Axis Vibration Actuators mounted at an angle Springs allow table to move in all axis Distribution of energy between axes fixed o Not monitored or controlled o Function of table and fixture construction Broadband Vibration Vibration frequency fixed by design Hammer rep rate and table resonances determine frequency content Slide Number: 36

37 Typical Spectrum From an RS Vibration System Courtesy of Qualmark Corporation Slide Number: 37

38 Typical Real Time Signal from RS Vibration System Courtesy of Qualmark Corporation Slide Number: 38

39 HALT and HASS Technology Designed specifically to rapidly fatigue products Excite the resonant frequency of all components Regardless of frequency Regardless of orientation Slide Number: 39

40 The HALT Process Slide Number: 40 Applied Reliability Symp posium, Asia Pacific 2012

41 HALT Process Includes Fixture development Ancillary test equipment Verify V functionality Run HALT (Determine robustness) Failure Analysis Implement I l t Corrective Action (CA) Repeat HALT (Verify CA) On-going evaluation Slide Number: 41

42 HALT Process Prior To Beginning g Meet with design engineers to discuss product attributes. o Determine stresses to apply. o Determine number of samples available. o Determine functional tests to run during Dev. HALT It is essential that the product being tested be fully exercised and monitored throughout HALT for problem detection o Determine what parameters to monitor o Determine what constitutes a failure o Develop Test Plan Slide Number: 42

43 HALT Process -Setup Design vibration fixture to ensure energy transmission to the product (different from electrodynamic vibration fixtures). Design air ducting to ensure maximum thermal transitions on the product. Tune chamber for product to be tested. Apply thermocouples to product to be tested. Setup all functional test equipment and cabling. Slide Number: 43

44 Fixturing Example Slide Number: 44 Applied Reliability Symp posium, Asia Pacific 2012

45 Fixturing Example Slide Number: 45 Applied Reliability Symp posium, Asia Pacific 2012

46 Fixturing Example Slide Number: 46 Applied Reliability Symp posium, Asia Pacific 2012

47 Highly Accelerated Test Sequence Thermal Step Stress Cold Step Stress Hot Step Stress Rapid Thermal Transition Cycling Vibration Step Stress Combined Environment Rapid Thermal Transition Cycling & Vibration Step Stress Slide Number: 47

48 HALT Process A step stress approach.. Stimuli D C B A Continue until operating & destruct limits of UUT are found or until test equipment limits are reached. 0:00 0:15 0:30 0:45 Time (hour:minute) Slide Number: 48

49 HALT Process Thermal Step Stress Begin with cold step stress and then hot step stress. Step in 10 C increments Dwell time minimum of 10 minutes + time to reach stability + time to run functional tests to ensure product is still functional. Start dwell once product reaches temperature setpoint, begin functional tests after 10 minute dwell. Continue until fundamental limit of technology is reached. Slide Number: 49

50 HALT Process Thermal Step Stress If circuits have thermal safeties, ensure operation & then defeat to determine actual operating & destruct limits. Apply additional product stresses during process o Power Supplies: Power cycling during cold step stress. o Input voltage variation. Load variations. o Frequency variation of clocks. Slide Number: 50

51 Margin Improvement Process Lower Destruct Limitit Lower Oper. Limitit Product Operational Specs Upper Oper. Limitit Upper Destruct Limitit Different Failure Modes Destruct t Margin Operating Margin Stress Slide Number: 51

52 Margin Improvement Process Lower Lower Upper Upper Destruct Oper. Product Oper. Destruct Limitit Limitit Operational Limitit Limitit Specs Different Falure Modes Destruct t Margin Operating Margin Stress Slide Number: 52

53 Low Temperature Step Stress Cold Temperature Step Stress Applied Reliability Symposium, Asia Pacific 2012 Temperaturee (C) :31 8:40 8:43 8:46 8:49 8:52 8:55 8:58 9:01 9:04 9:07 9:10 9:13 9:16 9:19 9:22 9:25 9:28 9:31 9:34 9:37 9:40 9:43 9:46 9:49 9:52 9:55 9:58 10:01 10:04 10:07 10:10 10:13 10:16 10:19 Time TC1 TC2 TC3 TC4 TC5 TC6 TC7 TC8 TC9 TC10 VDC11 VDC12 TC13 Slide Number: 53

54 High Temperature Step Stress Hot Temperature Step Stress Applied Reliability Symposium, Asia Pacific 2012 (C) Temperature : 11: 11: 11: 11: 11: 11: 11: 12: 12: 12: 12: 12: 12: 12: 12: 12: 12: 12: 13: 13: 13: 13: 13: 13: 13: 13: 13: 13: 13: 13: 14: 14: 14: 14: 14: Time TC1 TC2 TC3 TC4 TC5 TC6 TC7 TC8 TC9 TC10 VDC11 VDC12 TC13 Slide Number: 54

55 HALT Process Rapid Thermal Transitions Transition temperature as fast as chamber will allow. Select temperature range within 10 C of the operating limits found during thermal step stress. If product cannot withstand maximum thermal transitions, decrease transition rate by 10 C per minute until operating limit it is found. Continue series of transitions for a minimum of 5 cycles or 10 minutes (or time it takes to run set of functional tests). Apply additional product stresses during process. Slide Number: 55

56 Rapid Thermal Transition Response Deg C Board 1 Board 2 Board 3 0 Board 4 Slide Number: 56

57 HALT Process Vibration Step Stress Understand vibration response of product (i.e. how does product respond to increases in vibration input). Determine Grms increments (usually 5 Grms on product). Dwell time minimum of 10 minutes + time to run functional tests t to ensure product is still functional. Start dwell once product reaches vibration setpoint. Continue until reach fundamental limit it of technology. Apply additional product stresses during process. Slide Number: 57

58 Vibration Step Stress Vibration Step Stress Applied Reliability Symposium, Asia Pacific 2012 Grms :09 9:13 9:18 9:23 9:28 9:33 9:38 9:43 9:48 9:53 9:57 10:02 10:07 10:12 10:17 10:32 10:37 10:42 11:32 11:36 11:41 12:09 12:14 12:19 12:41 12:45 12:50 12:55 13:00 13:05 13:18 13:23 13:28 13:32 13:37 14:12 Time Temp Setpoint Temp Product Air Vibe Setpoint Vibe Product Slide Number: 58

59 HALT Process Combined Environment Use same thermal profile used during rapid thermal transitions. Incorporate additional product stresses into profile such as, power cycling. Step in (DL/5) Grms increments. At 20Grms and higher, h add tickle vibration (approximately 5Grms) to determine if failures that were precipitated at high G levels are only detectable at lower G level. Slide Number: 59

60 Combined Temperature & Vibration Combined Temperature and Vibration Applied Reliability Symposium, Asia Pacific 2012 Temperature (C) / Vibration (Grms) :22 14:25 14:28 14:31 14:35 14:38 14:41 14:44 14:47 14:51 14:54 14:57 15:00 15:03 15:07 15:10 15:13 15:16 15:19 15:23 15:26 15:29 15:32 15:35 15:39 15:42 15:59 16:02 16:06 16:12 16:15 16:18 16:21 16:24 16:28 Time Temp Setpoint t Temp Product Air Vibe Setpoint t Vibe Product Slide Number: 60

61 Failure Percentage By Stress Type Combined 32% Cold Step 19% Vibration 19% Rapid Thermal 9% Hot Step 21% 2011 Qualmark. Proprietary Data Slide Number: 61

62 When Failures Occur During HALT Stop test and record failure mode and stress level. Use isolation technique to identify failure location. Document failure location. Determine root cause cause. May require further investigating or FA lab. Implement temporary fix. Continue HALT and try to uncover additional failures. Slide Number: 62

63 HALT Process Post Testing Determine root cause of all failures that occurred. Meet with design engineers to discuss results of Developmental HALT and root cause analysis. Determine and implement corrective action. Perform Verification HALT to ensure problems fixed and new problems not introduced. d Periodically evaluate product as it is subjected to engineering changes. Slide Number: 63

64 Disciplines Required for HALT Design Team Manufacturing/Process Engineering Test Engineering i Failure Analysis Supply Line Management Reliability/Quality lit Engineering i Program Management age e Slide Number: 64

65 A Word of Wisdom Address All Failures Identified Up To The Fundamental Limit of The Technology - Even if Found Above Spec! Slide Number: 65

66 HALT/HASS Integral Throughout Product Lifecycle ENGINEERING CHANGE ORDER Re-HALT; New HASS Screen Limits DESIGN SG HALT Design; HALT Supply Chain Vendors PILOT BUILD HALT/HASS Development FIELD RETURN / DEPOT REPAIR HALT, re-hass QUALITY AUDIT Sample HALT/HASA Screening Quality and Reliability Processes are Closed Loop and Repetitive Throughout Product Life Cycles MATERIAL RECEIVING Sample or HALT/HASS/HASA screening PRODUCTION HASS Screen CONTRACT MANUFACTURE HASS/HASA Slide Number: 66

67 CASE STUDIES Slide Number: 67 Applied Reliability Symp posium, Asia Pacific 2012

68 An Evaluation of the Effects of Changes in Manufacturing and Design Technologies on the Results of Accelerated Reliability Testing Slide Number: 68

69 Background Information In 1996 findings from Qualmark s Santa Clara, CA lab Summary Of Halt And Hass Results At An Accelerated Reliability Test Center A valuable source of data that has been used extensively since then Slide Number: 69

70 A New Summary With New Data An Evaluation of the Effects of Changes in Manufacturing and Design Technologies on the Results of Accelerated Reliability Testing Repeats much of the analysis done in the 1996 Silverman paper, using current data Still using HALT report data from Qualmark s Authorized Test Centers Slide Number: 70

71 Key Metric Failure vs. Stress Stress Cold Step Hot Step Rapid Thermal Vibration Combined Total 1996 % 14% 17% 4% 45% 20% # % 19% 21% 9% 19% 33% # Qualmark proprietary data used with permission Slide Number: 71

72 Key Metric Failure vs. Stress Combined 20% Vibration 45% Cold Step 14% Hot Step 17% Rapid Thermal 4% Combined 32% Vibration 19% Failures Found by Stress Type Percentage Cold Step 19% Rapid Thermal 9% Hot Step 21% Qualmark proprietary data used with permission Slide Number: 72

73 Investigating g the Differences Data supports intuitive predictions Increased use of SMT has changed effectiveness of stress Vibration now accounts for only 19% of total failures, vs 45% in 1996 Without leaded parts or other massive parts on board, SMT is a very robust technology from a vibration standpoint. Qualmark proprietary data used with permission Slide Number: 73

74 Investigating g the Differences Combined environment remains critical In 1996, 1/5 of failure modes required a combined environment to be precipitated 1n /3. Combined environment is now the single most effective stress in HALT Qualmark proprietary data used with permission Slide Number: 74

75 Investigating g the Differences The total number of failures is also interesting In 1996, average was 5 failures/test In 2008, average was 6.25 failures/test Key conclusion A single HALT will, on average, bring out 5 or 6 failure modes in your product Qualmark proprietary data used with permission Slide Number: 75

76 One Last Interesting Data Point In 1996, the failure mode of Broken Lead accounted for 22% of the total In 2008, that number was 7% Qualmark proprietary data used with permission Slide Number: 76

77 StorageTek Cost of Quality Reven nues a % of Cost of Qua ality as Prevention & Appraisal In-house Failures Field Failures Year Source: C.T. Leonard Implementation of Stress Margin Approach, 6/5/95 Slide Number: 77

78 Cisco HALT Margin vs RMA rate RMA PPM VS. HALT MARGIN FOR GSR R MA PPM y = x HALT MARGIN ( C) Slide Number: 78

79 Summary Legacy approaches alone do not sufficiently test reliability HALT finds failure modes that can be missed by traditional test methods Unlike conventional testing HALT can extend operating margins HALT permits a reliability response to faster-to-market to market pressures Faster testing Better products Slide Number: 79

80 Where to Get More Information HALT Testing Guidelines - "HALT, HASS & HASA Explained, Accelerated Reliability Techniques, Revised Edition" by Harry W.McLean, ASQ ISBN "Accelerated Testing" a Practitioners Guide to Accelerated and Reliability Testing, by Bryan Dodson and Harry Schwab. IPC9592A a standard requiring HALT and recommending HASS ( Slide Number: 80

81 Questions Thank you for your attention. ti Do you have any questions? Slide Number: 81