werner kanert aim qm wtp - aecmain. kanert infineon, aim qm wtp qualiegies fication strataec rw 2006...

W. KanertInfineon, AIM QM WTPQualiegiesfication StratAEC RW 2006

Qualification Strategies in the Age of Zero Defect

AEC Reliability Workshop 09.-11.05.2006

Werner KanertAIM QM WTPInfineon


Outline

Stress-Test-Driven QualificationStress-Test-Driven Qualification

Ways to ProcedeWays to Procede

Failure-Mechanism-Driven QualificationFailure-Mechanism-Driven Qualification

PreludePreludeIntroductionIntroduction


SummarySummary

Knowledge-Based QualificationKnowledge-Based Qualification


Challenges for Reliability

Cost pressure

Shortertime-to-market

Increasing complexity of technologiesCMOS scalingIncreased power densityIntroduction of new materialsNew device structures

Reliability

Increasing customer requirementsLower failure rate / Zero DefectIncreased lifeteime /

temperature requirementsHarsh / safety critical applications


Reliability Qualification of Semiconductor ComponentsStatus

! De facto standards for qualification of semiconductorcomponents for automotive applications today

AEC Q100 for ICsAEC Q101 for Discretes

! Customer specific requirements for qualificationIn some cases extended tests

! De facto standards for qualification of semiconductorcomponents for automotive applications today

AEC Q100 for ICsAEC Q101 for Discretes

! Customer specific requirements for qualificationIn some cases extended tests

The qualification procedure has essentially remained unchangedover the years.

� AEC founded 1994

� JESD47 released 1995

The qualification procedure has essentially remained unchangedover the years.

� AEC founded 1994

� JESD47 released 1995

source ITRS 2006


Reliability Qualification of Semiconductor ComponentsNeed for Change

! Technology changes

! Increased requirements

! New applications

! Customers (tier1s) and OEMs

� express doubt about the established qualification procedure

� push for improved procedures.

Adaptation of the qualification process to today�s needs.

What is the way to assure reliability in the age of Zero Defect?


Outline






SummarySummary



Qualification Procedure Today:Stress-Test-Driven Qualification

! Standard procedure for qualifying semiconductor products today.

! Examples for standards:JEDEC JESD47AEC Q100 / Q101

! Uses a standardised set of stress tests to test the reliability of the products.

! Sample size is 77 or 45 (Q100) per lot.

! Acceptance criterion is zero fails.

! �These sets of tests should not be used indiscriminately.�(JESD47) " However: often used as a cookbook approach.


Getting Lifetimes from Standard Tests

! Taking one step further:Take a standard acceleration modelChoose some parameter values for the acceleration modelCalculate a lifetimebut:acceleration models are not determined and parameters are not measured

! Most simple approach:Assume that 1000h of test cover the lifetime of the device in the field.

How to assess the reliability of the component in the fieldbased on the qualification data ?


Arguments in Favour ofStress-Test-Driven Qualification

! Tests the actual product

! Ease of use

! Historically grown abundance of experience with stress-based testing

! �We�ve always done it that way.�

! Comparability of results

! Liability issues


Stress-Test-Driven QualificationDeficiencies

Stress-test-driven qualification does not give information on

# when the device will fail

# how the test conditions and results are related to useconditions

# what the weaknesses of the technology are

# if one technology is better or worse than another one


Outline






SummarySummary



Knowledge-Based Qualification �Basic Requirements and Application

! Requirements of the application(s), use conditions

! Potential failure mechanisms

! Acceleration models for the considered failure mechanism

$ Failure-Mechanism-Driven Qualification

! Has been applied to silicon wafer technology reliability since thebeginning(The predecessor of the IRPS was named �Physics of Failure�, startingin 1962)

� Examples: Electromigration, hot carrier injection, gate oxide integrity


Failure-Mechanism-Driven QualificationApplication to Packaging

! Rarely used today. Reasons include� Incomplete understanding of failure mechanisms

� Large variety of package configurations and materials

� Many different kinds of interfaces

� Many different and interacting parameters

! Need for� Better material characterization

� Finite Element Analysis (FEA) to gain understanding of stresses


Failure-Mechanism-Driven Qualification -Performing Stress Tests! Test parameters (stress conditions) have to be optimized with respect

to the failure mechanism to be addressed.Example: Whisker test

! Test structures have to be designed to address effectively the failure mechanism under consideration. They also have to be relevant to product design and operation. In some cases this test structure may be the product itself.

! Test duration should be long enough to allow a significant fraction of the samples to fail.

! Confirmation of the fails in the tests is necessary, i.e. the observed fails should be related to the failure mechanisms to be addressed. Different failures that may occur but are not correlated to the addressed failure mechanism have to be treated separately in thelifetime/risk assessment.


Failure-Mechanism-Driven QualificationDeficiencies

! Possibilities of acceleration may be limited. This can be due to e.g.

- physical factors- competing failure mechanisms- intrinsic robustness of the system- design.

$ An insufficient number of fails may occur during aneconomically acceptable test duration.

! Acceleration models and/or parameters may not be available.

► Estimation of the risk necessary, e.g. by using worst case assumptions


Knowledge-Based QualificationApplication

! Needs knowledge and expertise

! Needs cooperation between supplier and user

! Should be applied to new technologies and lead products

! Should concentrate on early development stages

� to investigate failure mechanisms

� to build up understanding of the process and product

! Allows effort for follower products to be reduced

! Can be combined with stress-test-driven qualification for followerproducts or uncritical applications


Knowledge-Based QualificationAdvantages

! Gives information on the failure mechanisms

! Allows better assessment of lifetimes and safety margins(robustness of the technology)

! Helps build up an understanding of the technology / product and thereby can lead to improvement


Outline






SummarySummary



Summary

! Today�s qualification standards need augmentation.

! The changes we perceive drive a corresponding change in theway to qualify semiconductor components.

! Knowledge-based qualification provides a way to

� improve the reliability assessment

� reduce cost and time-to-market.

! Broad-band stress-based testing will continue to have its rangeof applicability.

werner kanert aim qm wtp - aecmain. kanert infineon, aim qm wtp qualiegies fication strataec rw 2006...

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