Alex Krechmer, Chris Pawlowicz, Alexander Sorkin TechInsights 3000 - - PowerPoint PPT Presentation

Alex Krechmer, Chris Pawlowicz, Alexander Sorkin TechInsights 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 effect
• Case study
• Concept and SP method
• FIB PVC signal tracing method
• Result discussion and comparison with the

traditional technique

• Summary

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Why IC circuit analysis?

• IP assertion
• Design verification
• Competitive 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

5

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

D

G

H I

J 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 Storage Imaging (# hours) 365 80 ~300Hrs SEM time Engineering (# hours) 300+ 100+ ~200Hrs Operator (# 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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