Application of Time-Domain Reflectometry To Detect Interconnect Failures Mentors Dr. Yaw Obeng Dr. Chukwudi Okoro PML Semiconductor Electronics Division,

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Application of Time-Domain Reflectometry To Detect Interconnect Failures Mentors Dr. Yaw Obeng Dr. Chukwudi Okoro PML Semiconductor Electronics Division, NIST -Binayak Kandel Slide 2 Outlines Introduction How far we have come? 3-D stacking and Interconnects Project Goal Procedure Conclusion 2 Slide 3 How Far Have We Come? Electronic Numerical Integrator And Computer (ENIAC) -1946 17,468 vacuum tubes ~1800 square feet ~150 kW of power 3 http://www.fi.edu/learn/case-files/eckertmauchly/team.html Slide 4 How Far Have We Come? Ivy Bridge Processors -2012 1.4 billion transistors (Tri 3-D Transistors) 160 mm 2 die size 50% less power consumption than its predecessor. 4 http://www.digitaltrends.com/computing/getting-ready-to-cross-ivy-bridge-the-laymans-guide-to-intels-latest-processors/ Slide 5 TSV Connections 3-D Stacking Advantages: Increased portability Increased Functionality Increased Transmission Speed 5 IBMs new 3D manufacturing technology Slide 6 6 6 Interconnects Back-End-of-Line(BEOL) Connects individual components like transistors and capacitors Through-Silicon Via(TSV ) Vertical connections that pass through wafer or die Through-Silicon Via (TSV)..But the reliability of these interconnects are not studied well enough Slide 7 Reliability Challenges of TSV 7 Void occurred at the bottom of TSV, on the connecting Cu pad due to electromigration *Y.C. Tan et al, Electromigration performance of Through Silicon Via (TSV) A modeling approach **T. Frank et al, IRPS, 2011 Slide 8 Reliability Challenges Contd. 8 R ambient = 13.3xx R initial = 26.3xx R final = 30.6xx FAILURE How do we find out the location of these failures? Slide 9 Project Goal Determine the failure locations in interconnects using Time-Domain Reflectometry (TDR) 9 Slide 10 TDR Works on the same principle as radar TDR transmits a short rise time pulse along the conductor. Any discontinuities in the impedance causes signal to reflect back. 10 Discontinuitie s Time Amplitude T D = Distance v = Velocity of Propagation T = Time Slide 11 Why TDR (1)? Easy and accurate to locate failures like open termination or any kind of discontinuities. 11 Daeil et al,Early Detection of Interconnect Degradation using RF Impedance 2008 Slide 12 Why TDR (2)? 12 Daeil et al,Early Detection of Interconnect Degradation using RF Impedance 2008 Non destructive method to pinpoint failures Slide 13 Reliability Challenges Contd. 13 R ambient = 13.3xx R initial = 26.3xx R final = 30.6xx FAILURE How do we find out the location of these failures in the sea of TSVs? Use TDR. Slide 14 Prepare sample Learn to use LeCroy WaveExpert 100h Take TDR measurements Locate where failure occurred Correlate data measured from Vector Network Analyzer (VNA) with the TDR data 14 My Task 14 Test Sample LeCroy WaveExpert 100h S. Vahanen et al, 3D integration activities at CERN 2010 Slide 15 Acknowledgement Society of Physics Students Entire SPS and AIP Family National Institute of Standards and Technology(NIST) Dr. David Seiler, Dr. Yaw Obeng, Dr. Chukwudi Okoro, Dr. John Suehle Dr. Yaqub Afridi Entire PML Semiconductor and Electronics Division Family Fellow Summer Interns 15 Slide 16 Thank You! 16