EUFANET Workshop 2009

Cession 6 - Multiple FA techniques on advanced technologies

Sylvain DUDIT

EUFANET Workshop 2009 2

Summary

• Typical EFA flow

• Application on case of analysis

• Focus to put in place for a complex case of analysi s – Optical techniques for fault research and localizat ion– The FIB and AFM-P during the analysis– Knowledge for a failure analyst

EUFANET Workshop 2009 3

Summary

• Typical EFA flow

• Application on case of analysis

• Focus to put in place for a complex case of analysi s – Optical techniques for fault research and localizat ion– The FIB and AFM-P during the analysis– Knowledge for a failure analyst

EUFANET Workshop 2009 4

Typical EFA flow

Setup after preparation

Electrical setup

Frontsidepreparation

Backside preparation

FA_report

TRE

E-beam

SLS / DLS

EMMI

…

Depro-cessing

Physical analysis

RequestDocumentationsInformations

Defect reproduction

Sample preparation

Fail alwaysAfter

Sample prep

Fault research&

Localization

Sample Preparation

ForPhysical analysis

Physical analysis

Report

FA request

0.2 to 0.5 0.2 to 3 0.2 to 2 0.1 to 0.5 0.2 to 6 0.2 to 2 0.2 to 3 0.2 to 1

Best case: 1.5 Days

Worst case: 18 Days

Interaction with designer /Techno / Test neededDay time

AFM Prob

FIB

EUFANET Workshop 2009 5

• Typical EFA flow

• Application on case of analysis

• Focus to put in place for a complex case of analysi s – Optical techniques for fault research and localizat ion– The FIB and AFM-P during the analysis– Knowledge for a failure analyst

EUFANET Workshop 2009 6

Case of analysis (1/5)

• Analysis– Test chip analog and digital on 65nm technology– Fail on specific structure to track the problem @ metallization level– Output stuck @ - no evident over consumption observed

IN OUT

• For a failure analysis point of view– Case with no over consumption : Open, bridge, serial defects– Case with over consumption : short to GND, short to VDD,

EUFANET Workshop 2009 7

Case of analysis (2/5)

IN OUT

• Dynamic EMMI :– Transistor commutations– High EMMI spot (drawbacks for the low emitter)– No functionality after high EMMI spot– 3 IV impacted by the failure ?

• Next : – Laser stimulation – Goal : best fail understanding

EMMI results

EUFANET Workshop 2009 8

Case of analysis (3/5)

• Laser Stimulation– SIL220X benefits versus a 100X lenses

• Sensitivity, spatial resolution• Best fail understanding• 2 IV impacted by the failure ? (1 in accordance with EMMI

result)

IN OUT

IN OUT

EMMI results LS results

EUFANET Workshop 2009 9

IN OUT

IN OUT

EMMI resultsLS results

Case of analysis (4/5)

• TRE results– Not in total accordance with LS

and EMMI– 5 IV impacted by the failure ?

EUFANET Workshop 2009 10

Case of analysis (5/5)

OUTIN

• Conclusion about fail hypothesis :– Short @ VDD or GND on a very long path– 3 FA techniques of localization with results but without fine localization– DLS technique : Fail (pseudo static fail)

!!! Charge contrast technique use to have the good localization !!!

EUFANET Workshop 2009 11

• Typical EFA flow

• Application on case of analysis

• Focus to put in place for a complex case of analysi s – Optical techniques for fault research and localizat ion– The FIB and AFM-P during the analysis– Knowledge for a failure analyst

EUFANET Workshop 2009 12

Fault research & Localization

TLS – Obirch(Tiva)

EMMIstatic

EMMI + SLS

Top & Back sideTop side

- ESD - Hot carriers- Latch-up

PLS – Obic(Liva)

- Floating node- Non bias junction- Resistive path

EBT-Ebeam Tester

Top & Back side

Measurement :- Delay- Rise/fall time@ebeam probe point

TRE

Back side

Measurement :- Delay@transistor level

Dynamic faulttracking:- cross talk- Latch-up

EMMI + Laser tester

SDLEMMIDynamic

Back side

Timing analysisTester

EUFANET Workshop 2009 13

AFM Probing

Fault research & Localization

Electrical characterization by “in situ”contact

FIB

Front side modification

Backside modification

Cross-section

Ebeam Probe Pad Generation Charge

contrast

Current leakage mapping

Id/VdFAIL

Id/VdREF

60µA

15µA

EUFANET Workshop 2009 14

Knowledge for a failure analysis

Knowledge needed :

- Sample Preparation ( // polishing, chemical, micro drill …)- Electrical setup ( Power supplies , DC)- CAD navigation setup – Layout view- Optic Tester ( EMMI+SLS) (collaboration with the designers)

- Mechanical deprocessing- Chemical deprocessing- SEM Imaging- Fib editing (F / B) and X-sectioning

Knowledge needed :

- Sample Preparation ( // polishing, chemical, micro drill …)- Electrical setup ( Power supplies , DC)- Electrical setup AC :

°Pattern conversion & Optimization - CAD navigation setup

° Layout view°Netlist view°Schematic view

- Optic Tester 5 ( EMMI+ SLS + TRE + DLS)- E-beam- Comparison with simulation results (close collaboration with the designers)

- AFM probing- Mechanical deprocessing- Chemical deprocessing- SEM Imaging- Fib editing ( F / B) and X-sectioning