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Quality Reliability
Quality Information
Corporate Quality Policy goal exceed quality expectations customers. This commitment starts with management extends through entire organization. achieved through innovation, technical excellence continuous improvement.
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Figure VISHAY quality policy
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Quality Reliability
VISHAY INTERTECHNOLOGY; INC. ENVIRONMENTAL, HEALTH SAFETY POLICY VISHAY INTERTECHNOLOGY, INC. committed conducting worldwide operations socially responsible ethical manner protect environment, ensure safety health employees conduct their daily activities environmentally responsible manner. Protection Environment: Conduct business operation manner that protects environmental quality communities which facilities located. Reduce risks involved with storage hazardous materials. company also committed continual improvement environmental performance. Compliance with Environmental, Health Safety Laws Regulations: Comply with relevant environmental, health safety laws regulations every location. Maintain system that provides timely updates regulatory change. Cooperate fully with governmental agencies meeting applicable requirements. Energy, Resource Conservation Pollution Control: Strive minimize energy material consumption design products processes, operation facilities. Promote recycling materials, including hazardous wastes, whenever possible. Minimize generation hazardous non-hazardous wastes facilities prevent eliminate pollution. Manage dispose wastes safely responsibly.
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Quality Reliability
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Figure VISHAY Quality road
Quality System Quality Program
heart quality process VISHAY worldwide quality program. This program, which been place since early 90's, specifically designed meet rapidly increasing customer quality demands future. Vishay Corporate Quality implements Quality Policy translates requirements throughout worldwide organization. VISHAY Quality defined roadmap with specific targets along way. major target achieve world-class excellence throughout VISHAY worldwide 2008.
VISHAY Corporate Quality
VISHAY Corporate Quality defines implements VISHAY quality policy corporate level. acts harmonize quality systems constituent divisions implement Total Quality Management throughout company worldwide.
Vishay Zero Defect Program Exceeding quality expectations customers Commitment from management through entire organization Newest most effective procedures tools design, manufacturing testing management procedures (eg. SPC, TQM) Continuous decreasing numbers Failure Rate Detailed failure analysis using methodology Continuous improvement quality performance parts technology
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Vishay Semiconductors Quality Goals Methods
goals straightforward: Customer satisfaction through continuous improvement towards zero defects every area operation. committed meet customers' requirements terms quality service. order achieve this, build excellence into product from concept delivery beyond. Design-in Quality Quality must designed into products. VISHAY uses optimized design rules based statistical information. This refined using electrical, thermal mechanical simulation together with techniques such FMEA, DOE. Built-in Quality Quality built into VISHAY products using qualified materials, suppliers processes. Fundamental this techniques both VISHAY suppliers. these techniques, well tracking critical processes, reduces variability, optimizing process with respect specification. target defect prevention continuous improvement. Qualification products qualified before release submitting them series mechanical, electrical environmental tests. same procedure used changed processes packages. Monitoring selection same similar tests used qualification also used monitor short- longterm reliability product. (Statistical Process Control) essential part VISHAY process control. been established many years used tool continuous improvement processes measuring, controlling reducing variability. VISHAY Quality System VISHAY's facilities worldwide approved 9000. addition, depending their activities, some VISHAY companies approved recognized international industry standards such 9000. Each subsidiary goal fulfill particular requirements customers. Opto Divisions Vishay Semiconductor GmbH certified according 9001:2000, 9000 ISO/TS 16949.
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Inputs from: from:
Forecast
Order
Process Outputs
Parameter RProduct Sampl Proj VM,Cus tomer Acc. Cycle Time Sales/ASP Turns Data Base Products >3years
Division
Products Customer Requests Customer Qualitiy Other Agreements Standards Laws
Inventorries Promisses Turns
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ement (PDCA
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procedures used based upon these standards laid down approved controlled Quality Manual.
Total Quality Management
Total Quality Management management system combining resources employees, customers suppliers order achieve total customer satisfaction. fundamental elements this system are: Management commitment European Foundation Quality Management (EFQM assessment methodology) Empowered Improvement Teams (EITs) Supplier development partnership Quality tools Training Quality System VISHAY employees from senior management downwards trained understanding using TQM. Every employee plays part continuous improvement process which fundamental corporate commitment exceed customers' expectations areas including design, technology, manufacturing, human resources, marketing, finance. Everyone involved fulfilling this goal. management believes that this only achieved employee empowerment. VISHAY corporate core values Leadership example Employee empowerment Continuous improvement Total customer satisfaction Business excellence very essence VISHAY Quality Movement process.
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Training VISHAY maintains that only realize aims employees well trained. therefore invests heavily courses provide employees with knowledge they need facilitate continuous improvement. training profile been established employees with emphasis being placed Total Quality Leadership. long-term continuously improve training keep ahead projected changes business technology. EFQM Assessment Methodology From 1995, VISHAY started introduce EFQM (European Foundation Quality Management) methodology structuring Total Quality Management approach. This methodology, similar Malcolm Baldrige process, consists selfassessing various VISHAY divisions facilities according nine business criteria: Leadership People Policy Strategy Partnership Resources Processes People Results Customer Results Society Results Performance Results (See figure assessments conducted yearly basis trained empowered, internal VISHAY assessors. This permits identification keypriority improvement projects measurement progress accomplished. EFQM methodology helps VISHAY achieve world-class business excellence. Empowered Improvement Teams (EITs) VISHAY believe that every person company contribution make meeting target customer satisfaction. Management therefore empowers employees higher higher levels motivation, thus achieving higher levels effectiveness productivity. Empowered improvement teams, which both functional cross functional, combine varied talents from across breadth company. taking part training, these teams continually searching ways improve their jobs, achieving satisfaction themselves, company most important customer.
People People
RESUL
People related People related Results Results
Politicy Politicy ategy Partnerships Partnerships Resources Resources
Customer related Customer related Results Results Society related Society related Results Results
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Performance Performance Results Results
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Leadership Leadership
Figure EFQM criteria self-assessment
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Processes Processes
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Vishay Semiconductors Tools
part search excellence, VISHAY employs many different techniques tools. most important them are: Auditing well third party auditing employed approval 9000 customers, VISHAY carries internal external auditing. There common auditing procedure suppliers sub-contractors between VISHAY entities. This procedure also used inter-company auditing between facilities within VISHAY. based "Continuous Improvement" concept with heavy emphasis other statistical tools control reduction variability. Internal audits carried routine basis. They include audits satellite facilities (i.e., sales offices, warehousing etc.). Audits also used widely determine attitudes expectations both within outside company. more efficient promoting common understanding among team members methods principles used. Gauge Repeatability Reproducibility (GR&R) This technique used determine equipment's suitability purpose. used make certain that equipment capable functioning required accuracy repeatability. equipment approved before this technique. Quality Function Deployment (QFD) method translating customer requirements into recognizable requirements VISHAY's marketing, design, research, manufacturing sales (including after-sales). process, which brings together life cycle product from conception, through design, manufacture, distribution until served expected life.
Quality Service
VISHAY believes that quality service equally important technical ability products meet their required performance reliability. objectives therefore include: On-time delivery Short response time customers' requests Rapid informed technical support Fast handling complaints partnership with customers
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Failure Mode Effect Analysis (FMEA) FMEA technique analyzing possible methods failure their effect upon performance/ reliability product/process. Process FMEAs performed processes. addition, product FMEAs performed critical customer products. Design Experiments (DOE) There series tools that used statistical design experiments. consists formalized procedure optimizing analyzing experiments controlled manner. Taguchi factorial experiment design included this. They provide major advantage determining most important input parameters, making experiment
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Customer Complaints Complaints fall mainly into categories: Logistical Technical VISHAY procedure detailing handling complaints. Initially complaints forwarded appropriate sales office where in-depth information
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describing problem, using VISHAY Product Analysis Request Return Form (PARRF), considerable help giving fast accurate response. necessary send back product logistical reasons, Sales Office issues Returned Material Authorization (RMA) number. receipt goods good condition, credit automatically issued. there technical reason complaint, sample together with PARRF sent Sales Office forwarding Failure Analysis Department supplying facility. device's receipt will acknowledged report issued completion analysis. cycle time this analysis targets constantly monitored order improve response time. Failure analysis normally consists electrical testing, functional testing, mechanical analysis (including X-ray), decapsulation, visual analysis electrical probing. Other specialized techniques (i.e. LCD, thermal imaging, SEM, acoustic microscopy) used necessary. analysis uncovers quality problem, Corrective Action Report (CAR) format will issued. subsequent returns handled with procedure.
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Customer notifies Vishay Sales Customer notifies Vishay Sales Office complaint Sales obtains Office complaint Sales obtains necessary information about return necessary information about return using attached form (Product18353 Analysis using attached form (Product Analysis Request Return Form) Request Return Form)
Customer complaint Customer complaint regarding Commercial Aspects regarding Commercial Aspects e.g. Incorrect products, stock e.g. Incorrect products, stock rotation, wrong delivery times rotation, wrong delivery times quantities quantities
Customer complaint Customer complaint regarding Technical Aspects e.g. regarding Technical Aspects e.g. Product specification, Product specification, labeling error, packaging labeling error, packaging issues issues Customer sends samples Customer sends samples designated factory location designated factory location (communicated Sales) (communicated Sales)
Customer receives analysis Customer receives analysis report from Vishay with reference report from Vishay with reference number number
return procedure return procedure
Entitled Entitled return/replacement return/replacement products products
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Sales assign number Sales assign number Customer returns Customer returns product product
Complaint Return Procedure
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Product Analysis Request Return Form
Address Data
Customer: Address: Customer Ref.-No: Cust. Contact Person: E-Mail: Phone: Fax: Sales Ref.No: Sales Office: Incoming Date: Sales Contact Person: E-Mail: Phone: Fax:
ProductA nalysisRequest
Device: Date Code: Plant Code: Qty. Analysis: Failure Rate:
Failure description
Type Complaint (pls. specify) Electr. Mechan. Others Point Failure: Incoming Assembly Field Failure
Qualification Reliability Others
Stress Conditions before Failure:
(Temp Voltage Others)
Application:
(please specify)
Remarks Other Data:
(please specify)
ReturnRequest
Device: Date Code: Inv. No.: Commercial Return Technical Return CAR-No.
RMA-No. mandatory
Report:
Vishay
Issue: 02.10.2000
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Product Analysis Request Return Form (PARRF)
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Quality Reliability
Company Address
Number: Page:
Company Phone Number
VISHAY Company Name Report
Originator Vishay Part No.: Date Code: Device Type: Value: Tolerance: Number: Package Type:
Report Date:
Complete following applicable items:
Date Opened: Vishay Location: Customer: Customer Location: Customer Ref. Code: Customer Part No.: Customer P.O. No.: Analysis Code: Company Specific Information Plant code: Serial No.: size: Sample Qty: Failure rate:
APPROACH Disciplines below must completed requests. DISCIPLINE ESTABLISH TEAMS
DISCIPLINE DESCRIBE PROBLEM
DISCIPLINE CONTAINMENT ACTIONS
DISCIPLINE ROOT CAUSE/RESULTS
VALID, Disciplines must completed. DISCIPLINE CORRECTIVE ACTIONS
DISCIPLINE IMPLEMENT CORRECTIVE ACTIONS
DISCIPLINE PREVENT RECURRENCE
DISCIPLINE CONGRATULATE TEAM
Revised Approved
Form CQA004 04/26/02
Rev.: Date:
Date: Date Closed:
MANUFACTURER WORLD'S BROADEST LINE ISCRETE SEMICONDUCTORS PASSIVE COMPONENT
Confidential Information
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VISHAY form
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Change Notification product process changes controlled released (Engineering Change Notification). This requires approval relevant departments. case major change, change forwarded customers Sales/ Marketing before implementation. Where specific agreements place, change will implemented unless approved customer. Ship-to-Stock/Ship-to-Line (STS/STL) Many customers require devices shipped direct stock production line omitting goods inwards inspection. VISHAY welcomes such agreements part customer partnership program, which promises open approach every aspect business. product will only supplied there valid agreement place between companies. Such agreement details quality level targets agreed upon between companies methods used case problems.
Quality Reliability
Assurance Program Though both quality reliability designed into VISHAY products, three basic programs must assure them: Average Outgoing Quality (AOQ) testing followed sample testing measure defect level shipped product. This defect level (AOQ) measured (parts million). Reliability qualification program assure that design, process change reliable. Reliability monitoring program measure assure that there decrease reliability product. Program Before leaving factory, products sampled after 100% testing ensure that they meet minimum quality level measure level defects. results accumulated expressed (parts million). They measure average number potentially failed parts deliveries over period time. sample size used determined LTPD tables depending upon product. rejects allowed sample. value calculated monthly using method defined standard JEDEC where: number devices rejected -total number devices tested acceptance rate: number lots rejected -total number lots tested
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values recorded separately with regard electrical mechanical (visual) rejects product type package. actual qualification procedure depends which these combinations these) qualified. Normally there three categories qualification order degree qualification testing required: technology process (this includes design process)
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product re-designed product using qualified process package including piece-part material change manufacturing location Minor change process, assembly package Accelerated testing normally used order produce results fast. stress level employed depends upon failure mode investigated. stress test that level used gives maximum acceleration without introducing untypical failure mode. tests used consist following: High temperature life test (static) High temperature life test (dynamic) HTRB (High Temperature Reverse Bias) Humidity 85/85 (with without bias) HAST (Highly Accelerated Stress Test) Temperature cycling High-temperature storage Low-temperature storage Marking permanency Lead integrity Solderability Resistance solder heat Mechanical shock (not plastic packages) Vibration (not plastic packages) characterization devices only subjected preconditioning simulate board assembly techniques using methods defined standard JSTD 020A before being subjected stresses. Normally, endpoint tests related data sheet specified parameters. Additionally, they include: Destructive physical analysis X-ray Delamination testing using scanning acoustic microscope Thermal imaging Thermal electrical resistance analysis
Qualification procedure Qualification procedure
Wafer process Wafer process qualification qualification
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Package Package qualification qualification
Device Type Device Type qualification qualification
Monitoring Monitoring
Process change Process change qualification qualification
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TFDU 6102 TFDU 6108 TFDU 6102 TFDU 6108 Profile Transceiver Module Profile Transceiver Module
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Example QualPack
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Quality Reliability
Vishay Semiconductors Reliability Monitoring Wear
monitoring program consists short-term monitoring provide fast feedback regular basis case reduction reliability measure Early-life Failure Rate (EFR). same time, Longterm monitoring used determinate Long-term steady-state Failure Rate (LFR). tests used subset from those used qualification consist Life tests Humidity tests Temperature-cycling tests Solderability tests Resistance-to-solder-heat test actual tests used depend product tested. Depending assembly volume yearly monitoring wear test plan created. Wear data very important Opto electronic device. that data degradation curves made. These curves show long time behavior different devices. Some typical curves attached this report.
Reliability Principles
Reliability probability survival function time stress, usually expressed terms FITs (failures device hours). expressed F(t) R(t) R(t) F(t) where: R(t) probability survival F(t) probability failure F(t) 1-e-lt where instantaneous failure rate time thus, R(t) e-lt lifetime distribution hazard rate curve shown figure This curve also known 'bath-tub curve' because shape. There three basic sections: Early-life failures (infant mortality) Operating-life failures (random failures) Wear-out failures
failure failure rate rate
Early-life Early-life failures failures (EFR) (EFR)
Operating life failures Operating life failures (LFR) (LFR)
Wear-out Wear-out failures failures
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Figure Bathtub curve
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failure rate during constant (random) failure period determined from life-test data. failure rate calculated from formula: where
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failure rate (hours-1) number observed failures failure number time defect good sample size entire operating time number Components hours result expressed either 1000 component hours multiplying FITs multiplying 10-9 hours
Example Determination failure rate devices were operated over period 2000 hours with: failure (f1) after 1000 hours (t1) failure (f2) after 1500 hours (t2). failure rate given example calculated follows: 1000h 1500h 2000h
values given table
Number Failures 0.92 2.02 3.08 4.17 5.24 6.25 7.27 Table chart Confidence Level 2.31 3.89 5.30 6.70 8.00 9.25 10.55
Example failure rate population Using example with failure rate 2000 failures: confidence 3.08
3.08 3085 9.985
This means that failure rate population will exceed 3085 with probability
hours
That means that this sample average failure rate %/1000 hours 2000
Accelerated Stress Testing order able assure long operating life with reasonable confidence, VISHAY carries accelerated testing products. normal accelerating factor temperature operation. Most failure mechanisms semiconductors dependent upon temperature. This temperature dependence best described Arrhenius equation.
Observed failure rates measured above specific devices tested. predicted failure rate total population required, statistical confidence factors have applied. confidence factors obtained from "chi square" charts. Normally, these charts show value (2/2) rather than failure rate calculated dividing factor number component hours.
where Boltzmann's constant 8.63 10-5 eV/K Activation energy (eV) Operation temperature Stress temperature Operation failure rate Stress-test failure rate Using this equation, possible from stress test results predict what would happen normal temperature operation. Activation Energy Provided stress testing does introduce failure mode, which would occur practice, this method gives acceptable method predicting reliability using short test periods compared life device. necessary know activation
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energy failure mode occurring during accelerated testing. This determined experiment. practice, unusual find failure there random failure mode. this reason average activation energy normally used this calculation. Though activation energies vary between under conditions use, activation energies between used depending upon technology. Activation Energies common failure mechanisms activation energies some major semiconductor failure mechanisms given table below. These estimates taken from published literature.
Failure mechanism Mechanical wire shorts Diffusion bulk defects Oxide defects Top-to-bottom metal short
1000 1000
Activation Energy 1.02 1.77
Electro migration
Electrolytic corrosion Gold-aluminum intermetallics Gold-aluminum bond degradation Ionic contamination Alloy pitting
Acceleration factor Acceleration factor
100100
Table Activation energies common failure mechanism
155155 Temperature (°C) Temperature (°C)
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Failure rates quoted operating temperature confidence using activation energy (EA) optoelectronic devices.
Example Conversion Example life test transform operating temperature 328K 423K Acceleration factor
423K 328K
Figure Acceleration factor different activation energies normalized
328K
423K 3080 -258
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with confidence This figure re-calculated operating/junction temperature using this method.
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(Early Life Failure Rate) This defined proportion failures, which will occur during warranty period system which they were designed. order standardize this period, VISHAY uses 1000 operation hours reference period. This figure also used automotive industry; equates year life automobile. order estimate this figure, VISHAY normally operates sample devices hours under accelerated conditions detailed above. Arrhenius then used before calculate failure rate with confidence level This figure multiplied 1000 give failures 1000 hours give failure ppm. figures quoted (parts million). Climatic Tests Models Temperature cycling failure rate inverse power used model fatigue failures materials that subjected thermal cycling. purpose accelerated testing, this model relationship called Coffin-Manson relationship, expressed follows: stress where: Acceleration factor DTuse temp. range under normal operation DTstress temp. range under stress operation constant characteristic failure mechanism.
Failure mechanism wire bond failure Intermetallic bond fracture wire bond heel crack Chip-out bond failure Coffin-Manson exponent
Relative Humidity failure rate Moisture effect modeling based upon HowardPecht-Peck model using acceleration factor equation shown below: stress stress where: RHstress relative humidity during test RHuse relative humidity during operation Tstress temperature during test Tuse temperature during operation activation energy Boltzmann constant Material constant instance: RHstress RHuse Tstress Tuse This example shows transform test conditions into environmental into another test conditions. This equation applicable devices subjected temperature humidity bias (THB) testing. Using these acceleration factors useful lifetime calculated. Applying acceleration factor once more, useful lifetime moisture effect model parts subjected estimated following equation: test hours Useful life Years -hours year 8,617
Table Coffin Manson exponent
instance: stress
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Document Number: 82501 Rev. 1.3, 26-Aug-05
Quality Reliability
with: Test hours 1000 hours year 8760 1000 Useful life Years 13,5 years 8760
Handling Quality
Electrostatic Discharge (ESD) Precautions Electrostatic discharge defined high voltage, which generated when dissimilar materials move contact with another. This rubbing (i.e. walking carpet) passing over insulated object. Sometimes, easily detectable when person discharged ground (shock). Electronic devices irreversibly damaged when subjected this discharge. They also damaged they charged high voltage then discharged ground. Damage occur point process manufacture device. particular problem humidity which very common non-humidified air-conditioned buildings. just generated human body also occur with un-grounded machinery. cause device fail immediately damage device that will fail later. Whether this happens not, usually depends energy available pulse. ESD-sensitive VISHAY products protected means Protection structures chip protection measures during handling shipping VISHAY laid down procedures, which detail methods used protection against ESD. These measures meet exceed those EN61340-5-1 MIL-STD-1686, standards ESD-protective preventative measures. These include Grounded wrist straps Grounded benches Conductive floors Protective clothing Controlled humidity also lays down methods routinely checking these other items such grounding machines. semiconductor device only completely protected when enclosed This completely closed conductive container (i.e., sealed conductive box). Most packaging material (i.e. tubes) used semiconductors manufactured from antistatic material anti-static-coated material. This does mean
This means that operation environment good around years, calculated 1000h humidity stress test.
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Wafer Level Reliability Testing
increasing demand complex devices with reduced geometry, VISHAY committed enhancing improving process product quality through Wafer Level Testing (WLT). Through custom-designed standard test devices structures, on-going design well process quality reliability monitored both wafer package level. When implemented manufacturing process, they provide rapid means monitoring metal integrity parameter stability. main tests are: Electro-migration Commonly known SWEAT (Standard Wafer- Level Electro-migration Test), this test used metallization process quality monitor. Mobile instability Special sensitive transistors used together with built-in heaters measure effect movement mobile ions interface region.
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Quality Reliability
that devices completely protected from ESD, only that packing will generate ESD. Devices completely protected only when surrounded sides conductive package. should also remembered that devices equally easily damaged discharge from high voltage ground vice-versa. Testing resistance part qualification procedure. methods used detailed MILSTD-883 Method 3015.7 (Human Body Model) EOS/ESD-S5.1-1993 (Machine Model) specification. Latch-up latch-up effect state which impedance path results persists following input, output latch-up effect state which impedance path supply over voltage that triggers parasitic Thyristor. this effect over current occurs which destroy least supply voltage must back defined state. Normally, latch-up test carried just CMOS ICs. This CMOS latch-up test according JEDEC standard. Bipolar ICs, there standard available far. Soldering products tested ascertain their ability withstand industry standard soldering conditions after storage. general, these conditions follows. Hand soldering: from device body Wave soldering: Double-wave soldering according CECC 00802 maximum total restricted soldering operations Reflow soldering: convection soldering according CECC 00802 with maximum temperature maximum with total restricted soldering operations, soldering CECC 00802 with maximum temperature maximum with total restricted soldering operations Note: certain components have limitations their construction. pack When being stored, certain types device packages absorb moisture, which released during soldering operations, thus causing damage device. so-called effect such example. prevent this, Surface Mount Devices (SMD) evaluated during qualification, using test consisting moisture followed soldering simulation (pre-conditioning) then subjected various stress tests. table Number Moisture Sensitivity Levels different levels, floor life conditions well soak requirements belonging these levels described. device, which found deteriorate under these conditions, packaged dry-packed devices packed generally according EIA-583 Material Standards Moisture Sensitive IPC-SM-786 Procedures Handling Moisture Sensitive Plastic following general recommendations: Shelf life packaging months. After opening, devices should handled according specifications mentioned dry-pack label. exposure storage time exceeded, devices should baked: Low-temperature baking hours High-temperature backing hours
Floor Level Conditions
Life Time Unlimited year Weeks 696hrs
Soak Requirements Time (hours) Conditions
Table Moisture Sensitivity Levels
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Default value semiconductor manufacturer's exposure time (MET) between bake plus maximum time allowed distributor's facility. actual times used rather than default times, they must used they exceed default times. Floor life package after removed from pack (level after completion bake). Total soak time evaluation
Note: There possible floor lives soak times Level correct floor life will determined manufacturer will noted pack label Labels Moisture Sensitive
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Vishay Semiconductors Reliability Statistics Glossary
Definitions Accelerated Life Test: life test under conditions those more severe than usual operating conditions. helpful, necessary, that relationship between test severity probability distribution life ascertainable. Acceleration Factor: Notation: f(t) time transformation from more severe test conditions usual conditions. acceleration factor f(t)/t. differential acceleration factor df(t)/dt. Acceptance number: largest numbers defects that occur acceptance sampling plan still have accepted. Acceptance Sampling Plan: accept/reject test purpose which accept reject items material based random samples from lot. Assessment: critical appraisal including qualitative judgements about item, such importance analysis results, design criticality, failure effect. Attribute (Inspection By): term used designate method measurement whereby units examined noting presence absence) some characteristic attribute each units group under consideration counting many units not) possess Inspection attributes kinds: either unit product classified simply defective defective number defects unit product counted with respect given requirement requirements. Attribute Testing: Testing evaluate whether item possesses specified attribute. Auger Electron Spectrometer: instrument, which identifies elements surface sample. excites area interest with electron beam observes resultant emitted Auger electrons. These electrons have specific characteristics near surface elements. usually used identify very thin films, often surface contaminants. Availability (Operational Readiness): probability that point time system either operating satisfactorily ready placed operation demand when used under stated conditions. Average Outgoing Quality (AOQ): average quality outgoing product after inspection rejected lot, with replacement good units defective units found spection. Bathtub Curve: plot failure rate item (whether repairable not) time. failure rate initially decreases, then stays reasonably constant, then begins rise rather rapidly. shape bathtub. items have this behaviour. Bias: difference between s-expected value estimator value true parameter; Applied voltage. Burn-in: initial operation item stabilize characteristics minimize infant mortality field. Confidence Interval: interval within which asserted that parameters probability distribution lies. Confidence Level: Equals where risk (%). Corrective Action: documented design, process, procedure, materials change correct true cause failure. Part replacement with like item does constitute appropriate corrective action. Rather, action should make impossible that failure happen again. Cumulative Distribution Function (CDF): probability that random variable takes value less than equal value e.g. F(x) Defect: deviation item from some ideal state. ideal state usually given formal specification. Degradation: gradual deterioration performance function time. Derating: intentional reduction stress strength ratio application item, usually purpose reducing occurrence stressrelated failures. Duty Cycle: specified operating time item, followed specified time operation. Early Failure Period: That period life, after final assembly, which failures occur initially high rate because presence defective parts workmanship. This definition applies first part bathtub curve failure rate (infant mortality). Spectrometer: Generally used with scanning electron microscope (SEM) provide elemental analysis X-rays generated region being primary electron beam. Effectiveness: capability system device perform function. Electrical Overstress: electrical stressing electronic components beyond specifications. caused ESD.
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Electrostatic Discharge: transfer electrostatic charge between bodies different electrostatic potentials caused direct contact induced electrostatic field. Many electronic components sensitive will degraded fail. Expected Value: statistical term. random variable CDF, (x), where integration over continuous variables with pfd, this reduces discrete random variables with pfd, this reduces (xn) where over Exponential Distribution: 1-parameter distribution with: lexp (-t); (-t); (-t) failure rate mean time-to-failure This constant failure-rate-distribution. Failure: termination ability item perform required function. Failure Analysis: identification failure mode, failure mechanism, cause (i.e., defective soldering, design weakness, contamination, assembly techniques, etc.). Often includes physical dissection. Failure, Catastrophic: sudden change operating characteristics item resulting complete loss useful performance item. Failure, Degradation: failure that occurs result gradual partial change operating characteristics item. Failure, Initial: first failure occur use. Failure, Latent: malfunction that occurs result previous exposure condition that result immediately detectable failure. Example: Latent failure. Failure Mechanism: mechanical, chemical, other process that results failure. Failure Mode: effect which failure observed. Generally, describes failure occurs tells "how" with respect operation. Failure Rate: conditional probability density that item will fail just after time given item failed time number failures item unit measure life (cycles, time, miles, events, etc.) applicable item. Failure, Wearout: failure which time occurrence governed rapidly increasing failure rate. FIT: Failure Unit; (also, Failures Time) Failures hours. Functional Failure: failure whereby device does perform intended function when inputs controls correct.
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Gaussian Distribution: 2-parameter distribution with:
guaf (x). gaufc (x). "Mean value "standard deviation Hazard Rate: Instantaneous failure rate. Hypothesis, Null: hypothesis stating that there difference between some characteristics parent populations several different samples, i.e., that samples came from similar populations. Infant Mortality: Premature catastrophic failures occurring much greater rate than during period useful life prior onset substantial wear out. Inspection: examination testing supplies services (including when appropriate, materials, components, intermediate assemblies) determine whether they conform specified requirements. Inspection Attributes: Inspection whereby either unit product characteristics thereof classified simply defective defective number defects unit product counted with respect given requirement. Life Test: test, usually several items, made purpose estimating some characteristic(s) probability distribution life. Lot: group units from particular device type submitted each time inspection testing called lot. Reject Rate (LRR): reject rate percentage lots rejected form lots evaluated. Tolerance Percent Defective (LTPD): percent defective, which accepted minimum arbitrary fraction time, that percent defective whose probability rejection designated Mean: arithmetic mean, expected value; specifically modified defined, e.g., harmonic mean (reciprocals), geometric mean product), logarithmic mean (logs). Mean Life: R(t)dt; where R(t) s-reliability item; interval over which mean life desired, usually useful life (longevity). Mean-Life-Between-Failures: concept same mean life except that repaired items mean up-time item. formula same mean life except that R(t) inter-
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Quality Reliability
preted distribution up-times. Mean-TimeBetween-Failures (MTBF): particular interval, total functioning life population item divided total number failures within population during measurement interval. definition holds time, cycles, miles, events, other measure life units. Mean-Time-To-Failure (MTTF): "Mean Life". Mean-Time-To-Repair (MTTR): total corrective maintenance time divided total number corrective maintenance actions during given period time. MTTR: G(t)dt; where G(t) repair time; maximum allowed repair time, i.e., item treated repairable this echelon discarded sent higher echelon repair. Operating Characteristic (OC) Curve: curve showing relation between probability acceptance either quality process quality, whichever applicable. Part Million (PPM): arrived multiplying percentage defective 10,000. Example: 1,000 PPM. Population: totality items, units, measurements, etc., real conceptual that under consideration. Probability Distribution: mathematical function with specific properties, which describes probability that random variable will take value values. random variable continuous well behaved enough, there will pfd. random variable discrete, there will pmf. Qualification: entire process which products obtained from manufacturers distributors, examined tested, then identified Qualified Product List. Quality: property, which refers tendency item made specific specifications customer's express needs. current publications Juran, Deming, Crosby, Quality Assurance: system activities that provides assurance that overall quality control fact, being done effectively. system involves continuing evaluation adequacy effectiveness overall quality control program with view having corrective measures initiated where necessary. specific product service, this involves verifications, audits, evaluation quality factors that affect specification, production inspection, product service. Quality Characteristics: Those properties item process, which measured, reviewed, observed which identified drawings, specifications, contractual requirements. Reliability becomes quality characteristic when defined. Quality Control (QC): overall system activities that provides quality product service, which meets needs users; also, such system. Random Samples: commonly used acceptance sampling theory, process selecting sample units such manner that units under consideration have same probability being selected. Reliability: probability that device will function without failure over specified time period amount usage stated conditions. Reliability Growth: Reliability growth effort, resource commitment, improve design, purchasing, production, inspection procedures improve reliability design. Risk: probability rejecting null hypothesis falsely. Scanning Electron Microscope (SEM): instrument, which provides visual image surface features item. scans electron beam over surface sample while held vacuum collects several resultant particles energies. provides depth field resolution significantly exceeding light microscopy used magnifications exceeding 50,000 times. Screening Test: test combination tests intended remove unsatisfactory items those likely exhibit early failures. Significance: Results that show deviations between hypothesis observations used test hypothesis, greater than explained random variation chance alone, called statistically significant. Significance Level: probability that, hypothesis under test were true, sample test statistic would worse than observed test statistic. SPC: Statistical Process Control. Storage Life (Shelf Life): length time item stored under specified conditions still meet specified requirements. Stress: general ambiguous term used extension meaning mechanics that which could cause failure. does distinguish between
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Document Number: 82501 Rev. 1.3, 26-Aug-05
Quality Reliability
those things which cause permanent damage (deterioration) those things, which absence failure). Variance: average squares deviations individual measurements from their average. measure dispersion random variable data. Wearout: process attribution which results increase hazard rate with increasing (cycles, time, miles, events, etc.) applicable item.
Abbreviations
ECAP FMEA LTPD MTBF MTTF MTTR PRST Acceptable Quality Level Corrective Action Report Request Dual In-Line Package Electronic Circuit Analysis Program Electro Magnetic Compatibility Electro Magnetic Interference Electrical Overstress Electrostatic Discharge Failure Analysis Report Request (Failure Time) Failure Unit; Failures hours Failure Mode Effects Analysis Fault Tree Analysis Hazard Rate Tolerance Percent Defective Metal Oxide Semiconductor Material Review Board Mean-Time-Between-Failures Mean-Time-To-Failure Mean-Time-To-Repair Parts Million Probability Ratio Sequential Test Quality Assurance Quality Control Qualified Products List Reliability Planning Management Sneak Circuit Analysis Scanning Electron Microscope Wearout Time Hazard Rate Failure Rate (Lambda)
Document Number: 82501 Rev. 1.3, 26-Aug-05
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