(PoF) and Environmental Stress Screening - DfR Solutions

DfR Solutions works with companies and individuals throughout the life cycle of aproduct, lending a guiding hand on quality, reliability and durability (QRD) issuesthat allows your staff to focus on creativity and ideas.Our expertise in the emerging science of Electrical and Electronics ReliabilityPhysics provides crucial insights and solutions early in product design, developmentand test throughout manufacturing, and even into the field.Dr. Craig HillmanNASA – Johnson Space Center Houston, TX December 18, 2009© 2004 - 2007

Who is DfR Solutions?• We use Physics-of-Failure(PoF) and Best Practicesexpertise to provide knowledgebasedstrategic quality andreliability solutions to theelectronics industryTechnology InsertionDesignManufacturing and Supplier SelectionProduct Validation and Accelerated TestingRoot-Cause Failure Analysis & Forensics Engineering• Unique combination of expert consultants and state-ofthe-artlaboratory facilities5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com2

Who Uses DfR?Military / Avionics / Space Enterprise / Telecom / ATE Consumer / Appliance Industrial / PowerLockheed Martin Cisco Systems Dell Computers General ElectricNorthrop Grumman Huawei (China) Hewlett Packard SiemensGeneral Dynamics Sun Microsystems Apple Emerson ElectricBAE Systems Motorola Fujitsu (Japan) SchlumbergerHoneywell Alcatel-Lucent Samsung (Korea) Ingersoll RandHamilton Sundstrand Juniper Networks LG Electronics (Korea) Danaher MotionThales Communications KLA-Tencor Microsoft OlympusRockwell Collins Xerox Tyco ElectronicsAuto / TransportationPortables General Motors Components MedicalLG Electronics Caterpillar Samsung (Korea) Philips MedicalKyocera Panasonic Automotive Fairchild Semiconductor MedtronicTRW (England) International Rectifier GuidantContract Manufacturers Magna Nvidia Cardinal HealthFlextronics Takata (Japan) Amphenol Beckman CoulterBenchmark Electronics NIC BiotronikGold Circuit Electronics (Taiwan) Materials Cameron HealthDaeduck (Korea) Graftech Cardiac ScienceViasystems (China)Nihon Superior (Japan)And Many More….5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com3

How Do Companies Use DfR?• Work overflowMaximize the efficiency of your current staff• Independent party on critical design reviews• Supplier benchmarking (commodity / custom)• Test plan development and execution• Reliability predictions• Root-Cause AnalysisPb-FreeTransition• Continuing education5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com4

How is NASA using DfR?• Current focus is Technology InsertionWearout of semiconductor devicesIntroduction of water-soluble fluxes5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com5

DfR Solutions – Senior Experts• Dr. Craig Hillman, CEO and Managing Partner• Expertise: Design for Reliability (DfR), Pb-freeTransition, Supplier Benchmarking, PassiveComponents, Printed Circuit Board• PhD, Material Science (UCSB)• Dr. Nathan Blattau, Vice President• Expertise: Power Devices, DfR, Nonlinear FiniteElement Analysis (FEA), Solder Joint Reliability,Fracture, Fatigue Mechanics.• PhD, Mechanical Eng. (University of Maryland)• Cheryl Tulkoff, CRE• Expertise: Pb-Free Transition, PCB and PCBAFabrication, IC Fabrication, RCA (8D and Red X)• B.S., Mechanical Engineering (Georgia Tech)• Dr. Ron Wunderlich• Expertise: Design for EMI/EMC, Power Supply Design,Analog Circuit Design, Spice Model Development,Monte Carlo Circuit Simulation• PhD, Electrical Engineering (SUNY – Binghamton)• Greg Caswell• Expertise: Nanotechnology CMOS, CMOS/SOS, InputProtection Networks / ESD, SMT, Pb-free• B.S., Electrical Engineering (Rutgers)• Dr. Randy Schueller• Expertise: IC Fabrication, IC Packaging, Pb-FreeTransition Activities, Supplier Benchmarking, CorrosionMechanisms• PhD, Material Science (University of Virginia)• Dr. Randy Kong• Expertise: LEDs, LCDs, Microprocessors, MemoryComponents, Supply Chain Management, System-LevelReliability• PhD, Physics (CUNY)• James McLeish, CRE• Expertise: FMEA, Root-Cause Analysis, WarrantyAnalysis, Automotive Electronics, Physics of Failure,Battery Technology• M.S., Electrical Eng. (Wayne State University)• Norm Anderson• Expertise: Avionics, Product Qualification, SafetyCriticality Assessment, FTA, FMEA, ComponentUprating, Obsolescence• B.S., Electrical Engineering (Iowa State University)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com6

DfR Locations (North America)Seattle, WA425-279-3318Minneapolis, MN320-433-4075Binghamton, NY607-754-0347Rochester Hills, MI248-726-7600Austin, TX512-913-8624Corporate HeadquartersCollege Park, MD301-474-06075110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com7

Tech Insertion: Integrated Circuit WearoutService life, yrs.”The notion that a transistor ages is a new concept for circuit designers,” … aging has traditionally beenthe bailiwick of engineers who guarantee the transistor will operate for 10 years or so…But astransistors are scaled down further and operated with thinner voltage margins, it’s becoming harder tomake those guarantees… transistor aging is emerging as a circuit designer’s problem.IEEE Spectrum, June 20091000100Semiconductor lifetimesHi-Rel requirements101.00.1Computer, cell phone requirements1995 2005 2015500 250 130 65 35Semiconductor Feature Size, nm• Working with companies across the electronicsupply chain to develop an online solution5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com8

IC Wearout – Value Proposition• Tradeoff studies• Reliabilitypredictions• Systemprognostics andself-healing• Supplierengagement5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com9

Tech Insertion: 2 nd Gen Solder Reliability• Major solder manufacturer needed to demonstrate reliability of2 nd generation Pb-free alloy• DfR provided a turn-key solutionTest plan development (12 conditions) Test coupon design (CSP, TSOP, 2512)Test execution (temp cycle, vibe, shock)Failure analysisSolder reliability model creation• ResultsDeveloped new test technology to meetschedule and cost constraintsOnline calculators now available forcustomers world-wide5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com10

Design: Design for Excellence (DfX)• DfR uses industry-leading design for excellence (DfX) practicesto optimize design and ensure success early in new productdevelopment (NPD)• Expertise Circuit Analysis Power Supply Design Design for Reliability Design for Manufacturability Design for Testability Design for Environment Physics of Failure (PoF) Reliability Prediction Finite Element Analysis (FEA)• Focus Semiconductor Packaging Printed Circuit Board Circuit Card Assemblies Product and System-Level5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com11

DfX – A Software Solution5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com12

Supply Chain: Component Qualification• Working with major electronic OEMs onbenchmarking suppliers of criticalcomponents• Actions includeDeveloping test plansCharacterizing timeto failure behaviorDeveloping qualificationcriteria based on test results5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com13

Testing: Test Plan Development• Product test plans are critical to the success ofa new product or technologyStressful enough to identify defectsShow correlation to a realistic environment• DfR Solutions approachIndustry Standards + Physics of Failure• Results in an optimized test plan that isacceptable to management and customers• Experience in product test plans includeIndustrial controlsProcess monitoringConsumer appliancesTelecom (Class I, II, and III environments)Personal computersMobile phones and other mobile productsAvionics (engine controls, fuselage)Automotive (under-hood, passengercompartment, chassis, and trunk)Down-hole oil-drilling3σDesign Operating RangePerform SRTLimited Requalification?Month Cycles/Year Ramp DwellYOrder Limited Requalunits andPerform LimitedRe-qualificationNALT Plan ApprovalUpdate SRTUnits?MaxTemp(ºC)MinTemp(ºC)3σTCyclesper DayJan+Feb+Dec 90 6 hrs 6 hrs 30 5 25 1 12.654Mar+Nov 60 6 hrs 6 hrs 35 10 25 1 11.799Apr+Oct 60 6 hrs 6 hrs 40 15 25 1 10.944May+Sep 60 6 hrs 6 hrs 45 20 25 1 10.26Jun+Jul+Aug 90 6 hrs 6 hrs 50 25 25 1 9.576Operational 16.6 5 min 3 hrs 25 -40 65 1 2.223NYStartPerform Updateson SRT UnitsPass LimitedRe-qual?NFailure Analysis /RepairsYManufactureQualification andRGT UnitsPerform RGTALT ObjectiveMet?NRequest Guidancefrom GDYNFailure Analysis /RepairsSubmit FinalReportPerform QualUpdate RGTunits?YPerform Updateson RGT UnitsFinishPass Qual?AFNYOrder SRT Units5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com14

Root Cause Capability -- Personnel• The number one requirement in failureanalysis• All the necessary elementsElectrical engineers, mechanical engineers,materials scientists, inorganic chemists, etc.• Extensive in-house expertisePhD, MS, BS + industry experience• The right backgroundOver 800 failure analyses combined5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com15

Failure Analysis: Desktop Computer• Failures during HALTExposure to vibration• Electrical testing indicated electrical openUnder BGA socket• Validity of failure mechanism?Shearing of electrolytic capacitor leads• Dependent upon orientation of capacitorsOnly those along the board length• Vibration test may not have appliedrandom loadsPotential issues with vibration table orfixturing5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com16

Knowledge and Education (Website)• Let your staff learnall day / every dayE-LEARNING• Scholarly articles• Technical white papers• Case studies• Reliability calculators• Online presentations5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com17

Knowledge and Education (Onsite)• 4 hours to 5 days• Highly qualified instructors PhD, CRE, yrs of experience• Wide variety of topics Physics of Failure Design for Excellence Performing FMEA Pb-Free Reliability Capacitors Qualifying PCBs Opto-Electronics Component Packaging Root-Cause Analysis5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com18

Interested?• Could your next product benefit from DfR‟s extensiveexpertise and PoF knowledge base?Bring us in as an independent party during critical design reviews• Are your concerned with new technologies?DfR‟s scientists and engineers can provide comprehensive analysis toensure risk-minimization during these difficult transitions• Take advantage of our unique Open-Door policy!See how much we already know about your current issuesChances are we have already solved your problem at least once beforeWe work around the clock and around the worldContact us by phone (301-474-0607) or email (askdfr@dfrsolutions.com)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com19

Physics of Failure (PoF) andEnvironmental Stress Screening(ESS)Dr. Craig Hillman, Cheryl Tulkoff© 2004 - 2007

PoF and ESS• Can Physics of Failure be used to optimizean Environmental Stress Screen?What is Physics of Failure?Review of Environmental Stress ScreeningCombining the two5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com21

What is Physics of Failure?• DfR Solutions: Leverages the knowledge and understanding of the processesand mechanisms that induce failure to predict reliability and improve productperformance• Army: An engineering-based approach to reliability that uses modeling andsimulation to eliminate failures early in the design process by addressing rootcausefailure mechanisms in a Computer-Aided- Engineering environment• University of Maryland: Founded on the conviction that failures are governed byfundamental processes (mechanical, electrical, thermal, chemical, radiation) thatinitiate when the applied stress exceeds the material strength• NASA-JPL: Modeling of failure mechanisms, based on science/engineering first principles, that support deterministic orprobabilistic predictions of reliability and provide a scientific basisfor determining the effectiveness of screens or inspections5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com22

Physics of Failure (PoF) ModelingT f ~ 0.51eV exp kTexp(~0.063%RH )ttn1 2Ea12V V1expKB 1 T1T2L2 s c21T L F E1A1E2A2AsGsAcGc 9GbaLhh5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com23

Physics of Failure (cont.)• Reliability is the measure of a product‟s ability to…perform the specified function…at the customer (with their use environment)…over the desired lifetime• Physics of failure therefore requires an understanding of thedesign, desired lifetime and use environmentDesign: Architecture + MaterialsDesired lifetime: When the customer will be satisfiedUse environment: Must include assembly, transportation, storage,operation• Translation: PoF takes more effort5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com24

Examples: Desired Lifetime• Low-End Consumer Products (Toys, etc.) Do they ever work?• Cell Phones: 18 to 36 months• Laptop Computers: 24 to 36 months• Desktop Computers: 24 to 60 months• Medical (External): 5 to 10 years• Medical (Internal): 7 years• High-End Servers: 7 to 10 years• Industrial Controls: 7 to 15 years• Appliances: 7 to 15 years• Automotive: 10 to 15 years (warranty)• Avionics (Civil): 10 to 20 years• Avionics (Military): 10 to 30 years• Telecommunications: 10 to 30 years5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com25

Identifying the Field Environment• Temperature Cycling– Tmax, Tmin, dwell, ramp times• Sustained Temperature– T and exposure time• Humidity– Controlled, condensation• Corrosion– Salt, corrosive gases (Cl 2 , etc.)• Power cycling– Duty cycles, power dissipation• Electrical Loads– Voltage, current, current density– Static and transient• Electrical Noise• Mechanical Bending (Static and Cyclic)– Board-level strain• Random Vibration– PSD, exposure time, kurtosis• Harmonic Vibration– G and frequency• Mechanical shock– G, wave form, # of events5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com26

Environments: Transportation / StorageTemperature (°C)Container and Ambient TemperatureTemp.VariationTruckingContainer75.065.055.045.0Container Temp (°C)Outdoor Temp (°C)35.025.015.00 50 100 150 200 250 300 350 400 450Hours5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com27

% RHTransportation / Storage (cont.)Container and Ambient Relative HumidityHumidityVariationTruckingContainer100%90%80%70%60%50%40%30%20%10%0%INT. %RHEXT %RH0 50 100 150 200 250 300 350 400 450Hours5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com28

What is Screening?• The purpose of screening is to detect lifelimitingdefects before they reach thecustomer• Types of screensFunctional Testing (FCT)Burn-InMechanism-specificHighly Accelerated Stress Screening (HASS)Environmental Stress Screening (ESS)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com29

Four Rules of Stress Screening• Functional testing must be performed in-situ, during the screenRamp times and dwell times should be sufficiently long enough toensure a complete diagnosticIt is essential that the product being tested be fully exercised andmonitored for problem detection• The duration of the screen should be as short as possibleMay require periodic adjustment• Stress levels must be effective, but neither damage good productnor significantly reduce product life• Monitor results to determine effectiveness of screenAdjust stress screen as necessary to decrease “escapes” to the field5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com30

Failure RateStress Screening• Stress Screening is a closed-loop, 4 step process:PrecipitationDetectionFailure Analysis (root cause)Corrective Action• All four process stepsnecessary for successfulscreening programJust breaking and fixingis only first stepWithout proper failureanalysis, real risk of “walking wounded”Time5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com31

Types of Stress Screening• Detection screenConducted between specified environmental limitsDetects life-limiting defects• Precipitation screenConducted beyond specified environmental limitsPrecipitates defects (testing beyond operating limitsmay prevent detection)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com32

Burn-In• A screen consisting of a constanttemperature with applied voltageOriginally derived when military had problemsobtaining consistently good qualitysemiconductorsImprovements in quality and reliability ofsemiconductors have made this type of screenobsolete5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com33

Mechanism-Specific• Typically initiated after significant field issuePurpose is to regain confidence in supply chain ormanufacturing processApplied for a limited time period• Wider range of potential stressesMechanical shock, temperature/humidity/bias, etc.• Should be based on a physics-of-failure approachScreen should be long enough to precipitate the defect thatinitiated the field issue without removing significant life5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com34

HASS• HASS requires a prior, proper HALTIdentifies margins and provides opportunity to expand marginsIf only small margins exist (field vs destruct), then product is notscreenable using HASS• HASS consists of thermal cyclingIt is recommended to combine six-axis vibration, tickle vibration,power cycling, other stresses with thermal• Proof-of-screen is a mustProve validity of selected screen regimenEnsure no significant damage to good productEnsure minimal useful life has been removed[18,20]5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com35

HASS: Proof-of-Screen• Run for X times more than proposed screenIf no failures, one screen will leave a minimum of1 – 1/x life left in the product.• Recommendation: Test for a minimum of 20times the proposed screen length.A failure after 20 HASS screens tells us that onescreen will leave the product with 1 – 1/20 or 95%of its life5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com36

ESS• In industry, typically not designed toprecipitate• Thermal cycling between specified operatinglimitsSometimes includes vibration• Most common parameters2 to 10 cyclesAt least one fast ramp, one slow rampCombined with power cycling5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com37

Determining ESS Parameters• There are mathematical models provided fordetermining ESS parameters or„effectiveness‟Some of these models are based on PoFSome are empirical or statistical in nature• ExamplesMIL-HDBK-344AHughes SDO Model per RADC-TR-86-1495110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com38

Failure RateCan PoF improve ESS?Time5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com39

Failure RateCan PoF improve ESS? (cont.)• Can be challenging• Most algorithms assume „defect-free‟ stateWearout(design-driven)Infant Mortality(defect-driven)Time5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com40

How to use PoF in ESS?• Calculation of relative screening level• Calculation of life used / remaining life (ProcedureA4 in MIL-HDBK-344A) Thermo-mechanical fatigue of solder T 2 Mechanical fatigue of copper G 6.4Electromigration of aluminum exp(0.7eV/kT)• Note: To be most effective, „life used‟ should becalculated from the product design life, not just themission profile5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com41

‘Life Used’• MIL-HDBK-344A calculates life strictly from missionprofileActual life consumedmay be far less basedon the design life(PoF simulation)• Options for ESSStress to the equivalent of one (1) year of operation(satellite)Stress to the equivalent of X number of launches(manned flight)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com42

• “I am very interested in the physics of failurerelative to optimizing environmental stressscreening. What data is available to prove theadequacy/efficacy of “minimum screeninglevels” for thermal and vibration testing? Ifyou have anything that validates the levels inMil-hnbk-344 or Mil-Std-1540, or Tri-servicesBest Practices, et al, would be veryinterested.”5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com43

Desired Lifetime (IC Wearout)MeanServicelife, yrs.1000100101.00.1Process Variabilityconfidence boundsTechnology0.5 mm 0.25 mm 130 nm 65 nm 35 nm1995 2005 2015Year producedKnown trends for TDDB, EM and HCI degradation(ref: extrapolated from ITRS roadmap)AirplanesComputerslaptop/palmcell phones(courtesy of J. Bernstein, UMD)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com44

Desired Lifetime (Capacitor Wearout)• Ceramic chip capacitors with high capacitance / volume (C/V) ratiosCan fail in less than one year when operated at rated voltage and temperature5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com45

Desired Lifetime (Solder Wearout)Performance Needs• Higher frequencies and data transfer ratesLower resistance-capacitance (RC) constants• Higher densitiesMore inside less• Lower voltage, but higher currentJoule heating is I 2 R• Has resulted in less robust package designs5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com46

Solder Wearout (cont.)• Elimination of leaded devicesProvides lower RC and higher package densitiesReduces complianceCycles to failure-40 to 125C QFP: >10,000 BGA: 3,000 to 8,000CSP / Flip Chip:

Solder Wearout (cont.)• Design change: More silicon, less plastic• Increases mismatch in coefficient of thermalexpansion (CTE)BOARD LEVEL ASSEMBLY AND RELIABILITYCONSIDERATIONS FOR QFN TYPE PACKAGES,Ahmer Syed and WonJoon Kang, Amkor Technology.5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com48

Characteristic Life (Cycles to Failure)Solder Wearout (cont.)• Hotter devicesIncreases change in temperature (T)10000t f = T n900080007000n = 2 (SnPb)n = 2.3 (SnNiCu)n = 2.7 (SnAgCu)60005000400030002000100000 50 100 150 200Change in Temperature ( o C)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com49

Environments (Mechanical Shock)• Initially driven by experiences during shipping andtransportation• Increasing importance with use of portableelectronic devicesA surprising concern for portable medical devicesFloor transitions (1 to 5 inch „drop‟)• Environmental definitionsHeight or G levelsSurface (e.g., concrete)Orientation (corner or face; all orientations or worst-case)Number of drops5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com50

JESD22-B110A, Subassembly Mechanical Shock5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com51

Mechanical Loads (Vibration)• Exposure to vibration loads can result inhighly variable resultsVibration loads can vary by orders of magnitude(e.g., 0.001 g 2 /Hz to 1 g 2 /Hz)Time to failure is very sensitive to vibration loads(t f W 4 )• Very broad range of vibration environments MIL-STD-810 lists 3 manufacturing categories, 8transportation categories, 12 operationalcategories, and 2 supplemental categories5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com52

5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com53

Random Vibration (Examples)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com54

Vibration (cont.)• Vibration loads can be very complex Sinusoidal (g as function of frequency) Random (g2/Hz as a function of frequency) Sine over/on random• Vibration loads can be multi-axis• Vibration can be damped or amplifieddepending upon chassis/housing Transmissibility• Response of the electronicswill be dependent uponattachments and stiffeners• Peak loads can occur overa range of frequencies Standard range: 20 to 2000 Hz Ultrasonic cleaning: 15 to 400 kHz5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com55

Vibration (cont.)• Failures primarily occur when peak loadsoccur at similar frequencies as the naturalfrequency of the product / design• Natural frequenciesLarger boards, simply supported: 60 – 150 HzSmaller boards, wedge locked: 200 – 500 HzGold wire bonds: 2k – 4kHzAluminum wire bonds: >10kHz5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com56

Field Environment (Best Practice)• Use standards when…Certain aspects of your environment are commonNo access to use environment• Measure when…Certain aspects of your environment are uniqueStrong relationship with customer• Do not mistake test specifications for theactual use environmentCommon mistake with vibration loads5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com57

Ceramic Capacitors (Wearout)• Ceramic caps are typically not expected to experience„wearout‟ during normal operation• where t is time, V is voltage, T is temperature (K), n is aconstant (1.5 to 7), E a is an activation energy (1.3 to 1.5)and K B is Boltzman's constant (8.62 x 10 -5 eV/K)• May be no longer applicable for next generation capacitorswith high capacitance per volume (C/V)ttn1 2Ea12V VSub-2 micron dielectric thickness1exp 1 TGreater than 350 layers (increased failure opportunity)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com58KB1T2

DfR (Electrolytic Capacitors)• How do electrolytic capacitors fail?Evaporation of the liquid electrolyte• Manufacturer integrity testsPerformed at high temperatures (85ºC, 105ºC) for shortperiods of time (1000 – 5000 hours)• How to extrapolate to actual use conditions?L r = rated lifetime, V r = rated voltage, V 0 = actual voltage,T r = rated temperature, T 0 = actual temperatureFormula used by Panasonic, Hitachi, and Nichicon5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com59

Step 7: End-of-Life Simulation5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com60

Physics of Failure• Based on how the product could fail (failuremodels)Very important (need to avoid wearout)• Requires extensive knowledge on useenvironment• Can be difficult to apply to the majority of thelife curveInfant mortality and „steady-state‟ behaviorUncertainty and inconsistency in incorporating theinfluence of defects5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com61

Simulation for End-of-Life Prediction• What could experience wearout during the designlife?State-of-the-art integrated circuits w/sub 100 nm featuresize• Dielectric breakdown, electromigration, hot carrier injectionCapacitors (discussed previously)• Electrolytic capacitors, state-of-the-art ceramic capacitorsRelays / Switches• No easily usable failure modelInterconnects• Plated through holes, solder joints5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com62

Life Predictions of Integrated Circuits• Rarely performed outside of the IC manufacturerWhy?• Information necessary to perform the calculations notreadily availableDesign parameters, materials• IC manufacturer‟s incorporate modifications to improvelifetimeCan make available models widely inaccurate in regards toabsolute predictions• Uncertainty in regards to the validity of extrapolatingfrom single acceleration factorLife tests often increase temperature, but maintain electricalstresses constant5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com63

Plated Through-Hole (PTH) Fatigue• PTH fatigue is thecircumferential cracking of thecopper plating that forms thePTH wall• Driven by differentialexpansion between thecopper plating (~17 ppm) andthe out-of-plane CTE of theprinted board (~70 ppm)• Validated industry failuremodel available IPC-TR-5795110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com64

IPC TR-579• Determine stress applied (σ)Assumes perfectly elastic deformation when below yieldstrength (Sy)Linear stress-strain relationship above Sy• Determine strain range (∆ε)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com65

IPC-TR-579 (cont.)• Apply calibration constants Strain distribution factor, K d (2.5 –5.0)• 2.5 recommended Quality index, K Q (0 –10)• Iteratively calculate cycles-to-failure (N f )5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com66

Assessment of IPC-TR-579• Based on round-robin testing of 200,000 PTHs Performed between 1986 to 1988 Hole diameters (250 µm to 500 µm) Board thicknesses (0.75 mm to 2.25 mm) Wall thickness (20 µm and 32 µm)• AdvantagesAnalytical (calculation straightforward)Validated through testing• DisadvantagesNo ownershipValidation data is ~18 years oldUnable to assess complex geometries (PTH spacing, PTH pads)• Complex geometries tend to extend lifetimeDifficult to assess effect of multiple temperature cycles• Can be performed using Miner‟s RuleSimplified assumptions (linear stress-strain above yield point)How does one determine the quality index in the design phase?5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com67

PTH Quality Index5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com68

DfR – Solder Joints• Failure of solder joints isone of the primary wearoutmechanisms in electronicproductsMaybe changing• Especially true in productsused outside of commercial/consumerenvironmentsLonger required lifetimeMore severe operating conditions5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com69

DfR and Solder Joint Reliability• How do many companies currently ensure solderjoint reliability during the design phase?Not performedAccelerated tests based on industrial/military standards(MIL-STD-883, MIL-STD-810, JEDEC JESD-22, and IPC-TM-650)• This „benchmarking‟ does not allow for a directcorrelation between time under test to time in thefieldNo acceleration factorRisk of over or under testing5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com70

Solder Joints (cont.)• How do nominal solder joints fail?• WearoutThermal cycling• Changes in ambient temperature• Power cyclingVibration/Cyclic BendingCombined• OverstressMechanical shock5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com71

Thermal Cycling• Components most susceptibleLeadless• Chip components,• Crystals, oscillators, filters• Area array devices (BGA, CSP, COB)CTE mismatch between component and board• Ceramic devices (resistors, alumina substrates)• Devices with Alloy 42 leadframeSingle-sided solder joints• More sensitive to process variations• Components of minimal concernLeaded devices with copper leadframeDouble-sided insertion mount5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com72

Stress Relief600 hrs• Axial diodeDouble-sided insertionmount solder jointTemp. cycling of-40 to 130ºC• Crack propagationInitially observed after600 hrsNo significant increase incrack length after 1200additional hours1800 hrs5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com73

Thermal Cycle Life Model (Norris-Lanzberg)• Provides the appropriate test condition for agiven field environment (acceleration factor)Can not provide an absolute predictionf is cycling frequency, T is change intemperature, and T max is the maximumtemperature• “o” refers to operating environment and “t” refers to testenvironment5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com74

Thermal Cycle Life Model (Engelmaier)• Modified Coffin-MansonSemi-empirical analytical approach• Determine the strain range (g) x is strain correction factor (0.7 – 1.5), L D isdiagonal distance, is CTE, T is temperaturecycle, h is solder joint height5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com75

Engelmaier (cont.)• Determine fatigue ductility exponent (c) T sj is average temperature, t D is dwell time (min.)• Calculate cycles-to-failure (N 50 ) e f is fatigue ductility coefficient (0.325) and N is cycles to50% failure5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com76

Engelmaier (Discussion)• Most popular Adopted by IPC (D-279, SM-785, 9701)• Initially limited to 0 to 100ºC Subsequent publications suggest validity out to -40 to 125ºC• Use of empirically derived constants allow for curve fitting Engelmaier model will fit most failure data Constants tend to be package specific• Parameter limitations Solder joint height, h, should be approx. 4 mil (100 mm) for nonareaarray devices Diagonal length, L D , tends to have a limited influence beyond20 x 20mm for ball grid array devices• Tends toward conservative• Variation of this model available for leaded devices (incorporateslead stiffness)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com77

Thermal Cycle Life Model (Darveaux)• Unified energy approach Determines energy dissipated with eachtemperature cycle• Applicable to finite element analysis (FEA)• Advantages Has the potential to provide a moreaccurate life prediction Complex or unique package styles• Disadvantages Requires specialized software (FEA)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com78

Vibration (MIL-STD-810, Section 514.4)PSD (G 2 /Hz)• Provides the appropriate test condition for agiven field environment (acceleration factor)Can not provide an absolute prediction PSD PSD124TT2110.1PSD in g 2 /HzT is duration ofexposure0.010.0010.00010.00001TestField10 100 1000 10000Frequency (Hz)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com79

Vibration (Steinberg)• Step 1: Calculationof maximumdeflection (Z 0 )Z09.83 PSD 2f2nfnQPSD is the power spectral density (g 2 /Hz),f n is the natural frequency of the CCA,Q is transmissibility (assumed to be square root ofnatural frequency)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com80

Vibration (Steinberg)• Step 2: Calculatecritical displacementB is length of PCBparallel to componentc is a componentpackaging constant• 1 to 2.25h is PCB thicknessr is a relative positionfactor• 1.0 when component atcenter of PCBL is component length0. 00022BZ cchr L• At critical displacement,component can survive aminimum 20 million cycles underrandom vibration• Recent modifications have alsoincluded the influence of curvature5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com81

Vibration (Steinberg)• Step 3: Life calculation6.4 Z N c is 20 million cycles0 N N cc Z• Several assumptions0 CCA is simply supported on all four edges• More realistic support conditions, such as standoffs or wedge locks,can result in a lower or higher displacementsChassis natural frequency differs from the CCA natural frequencyby at least factor of two (octave)• Prevents couplingVibration occurs at room temperature• Depending upon the configuration and loading, vibration at lower orhigher temperatures can increase/decrease lifetimeDoes not consider the influence of in-plane displacement (i.e., tallcomponents)5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com82

TemperatureTemperature Cycling + Power Cycling• Product qualificationbased on power cyclingTime to failure for SnPbsolder is relativelyindependent of dwellAcceleration is simplythrough an increase infrequencyAcceleration factorsgreater than 120 easilyattainable6050403020100-0.4512:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AMTime• Combined testing should beperformed at both hot andcold dwells2.051.551.050.550.055110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com83

Combined (Temp Cycling/Vibration)• True field conditionComplex stress state• Performed primarily by avionicsCorrelation to field difficult5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com84

Mechanical Shock / Drop Testing• Heavily based on military andindustry specificationsRandom events difficult to captureand characterize• Primary driver for failure is outof-planedisplacementSimilar to vibration• Solder joint failure sensitive tointermetallic thicknessPreconditioning may be appropriateCorrelation to field environment based onArrhenius equation and activation energy of 0.5 eV5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com85

Mechanical Shock• Experienced during both shipping and installation• Options IEC 60068-2-31 (mentioned in IEC 61298)• Four drops (one per edge)• Drop from 25, 50, or 100 mm• Angled at 30º IEC 60068-2-27• 50G peak load with 11 millisecond pulseMIL-STD-8105110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com86

Product Qualification (other)• Mixed Flowing Gas (MFG)Used to simulate corrosive mechanisms found inequipment exposed to industrial environmentsConsists of Cl 2 , H 2 S, SO 2 , and NOxMost commonly used for connectors or products used inparticularly corrosive environments (under sink, paperprocessing, etc.)• Salt Spray• Water Spray• EMI/EMC• ESD5110 Roanoke Place, Suite 101, College Park, Maryland 20740Phone (301) 474-0607 Fax (240) 757-0053© 2004 - 2007 2009 www.DfRSolutions.com87