Alex Krechmer, Chris Pawlowicz, Alexander SorkinTechInsights 3000 Solandt Road, Ottawa, ON, K2K2X2,

Canada.Michael W. Phaneuf

FIBICS 1431 Merivale Rd #100, Ottawa, ON, K2E0B9, Canada.

Purpose.Find an alternative way to trace long

distributed signals on an IC such as power management control, clock etc.Test usage of Passive Voltage Contrast (PVC)

effect in a Focused Ion Beam (FIB) to trace a particular signal.Develop reliable technique for Sample

Preparation (SP) and for PVC use in FIB.Compare efficiency of PVC FIB signal tracing

with a traditional approach.

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Outline.Intro to Integrated Circuit (IC) competitive

analysis Traditional process flow and challenges.Intro to FIB PVC effectCase studyConcept and SP methodFIB PVC signal tracing methodResult discussion and comparison with the

traditional techniqueSummary

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Why IC circuit analysis?IP assertionDesign verificationCompetitive analysis.

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Intro to IC circuit analysis process flow.

Study die Photo

Delayered set exist?

Define ROI

SEM images & process

Circuit Read-Back

Missing circuit part

End

Delayer full set

yes

yes

no

no

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Challenge tracing long distributed signal.

Signal of interest goes out of predefined ROI. Duration, cost and

effort can be significant and not predictable.Entire die imaging

can be extremely expensive.

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A DG

H

IJ

K

Intro to FIB PVC effect.

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FIB Image+ ++++++

+ ++++++

FIB image contrast compare: “floating” vs. “grounded” structures.

PVC effect diagram

Intro to FIB PVC effect.

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Externally grounded probe tip is introduced into the

FIB chamber

Case study.

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xx

Bulk Si

Concept and Sample Prep.

Remove Bulk Si De-layer the

sample to M1.

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Package

Concept and Sample Prep.Identify start point

(Buffer Input) in the buffer chain.Connect a ground

signal to the start point.An output node of a

previous buffer in the chain will appear bright on FIB image.

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Package

Ext. Ground

FIB PVC signal tracing.Buffer bypass by

FIB deposition

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In Out-In Out

FIB PVC signal tracing.

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Buffer recognition Dielectric patch deposition

+Metal nodes exposure

Nodes short by conductor material

deposition

FIB PVC signal tracing.

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FIB buffer bypass short

Power Switches Inputs

Next Buffer Output

Results discussion.82 ‘jumps’ brought

us to the Power Management Controller block

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Typical Buffer Last Jump

Techniques comparison.A comparison of key metrics was made between two

approaches- traditional Reverse Engineering (RE) and FIB PVC.

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Traditional RE

FIB Signal Tracing Saved

Project Duration 4 months 2 months 50%Imaging (# images) 22000 100 >200GB StorageImaging (# hours) 365 80 ~300Hrs SEM timeEngineering (# hours) 300+ 100+ ~200HrsOperator (# hours) 50+ (Lab) 30+ (Lab) ~20Hrs

Summary.A new method for circuit tracing and circuit

analysis was developed based on PVC phenomena which was well known in FA to identify breakage in conductors.Using this patented technique titled “Circuit

tracing using a focused ion beam”, specific circuits and functional blocks can be localized in a reasonably short amount of time. Previously cost-prohibitive or high risk projects

can now be successfully completed at reduced time and cost.

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Q&A

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Thank you.

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