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. 2

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 3

Why IC circuit analysis?  IP assertion  Design verification  Competitive analysis. 4

Intro to IC circuit analysis process flow. Study die Photo Define ROI no Delayered Delayer full set set exist? yes SEM images & process Circuit Read-Back yes Missing circuit part no End 5

Challenge tracing long distributed signal.  Signal of interest goes out of predefined ROI.  Duration, cost and G effort can be D A H significant and not K predictable. I J  Entire die imaging can be extremely expensive. 6

Intro to FIB PVC effect. PVC effect diagram + ++ + ++ ++ ++ FIB Image ++ ++ FIB image contrast compare: “floating” vs. “grounded” structures. 7

Intro to FIB PVC effect. Externally grounded probe tip is introduced into the FIB chamber 8

Case study. xx 9

Concept and Sample Prep. Bulk Si  Remove Bulk Si  De-layer the Package sample to M1. 10

Concept and Sample Prep.  Identify start point (Buffer Input) in the buffer chain. Ext. Ground  Connect a ground signal to the start point. Package  An output node of a previous buffer in the chain will appear bright on FIB image. 11

FIB PVC signal tracing.  Buffer bypass by In Out-In Out FIB deposition 12

FIB PVC signal tracing. Nodes short by Dielectric patch Buffer recognition conductor material deposition deposition + Metal nodes exposure 13

FIB PVC signal tracing. Next Buffer Output Power Switches Inputs FIB buffer bypass short 14

Results discussion.  82 ‘jumps’ brought us to the Power Management Controller block Typical Buffer Last Jump 15

Techniques comparison.  A comparison of key metrics was made between two approaches- traditional Reverse Engineering (RE) and FIB PVC. Traditional FIB Signal Saved RE Tracing 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 16

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. 17

Q&A 18

Thank you. 19