Lecture_5 - 9/13/2011 Overview Motivation Fault Modeling...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 ECE 553: TESTING AND TESTABLE DESIGN OF DIGITAL SYSTES Fault Modeling 9/13/2011 2 Overview • Motivation • Fault Modeling – Why model faults? – Some real defects in VLSI and PCB – Common fault models – Stuck-at faults – Transistor faults • Summary 9/13/2011 3 Motivation – Models are often easier to work with – Models are portable – Models can be used for simulation, thus avoiding expensive hardware/actual circuit implementation – Nearly all engineering systems are studied using models – All the above apply for logic as well as for fault modeling 9/13/2011 4 Why Model Faults? I/O function tests inadequate for manufacturing (functionality versus component and interconnect testing) Real defects (often mechanical) too numerous and often not analyzable A fault model identifies targets for testing A fault model makes analysis possible Effectiveness measurable by experiments 9/13/2011 5 Some Real Defects in Chips Processing defects Missing contact windows Parasitic transistors Oxide breakdown . . . Material defects Bulk defects (cracks, crystal imperfections) Surface impurities (ion migration) . . . Time-dependent failures Dielectric breakdown Electromigration NBTI (negative bias temperature instability) . . . Packaging failures Contact degradation Seal leaks . . . Ref.: M. J. Howes and D. V. Morgan, Reliability and Degradation - Semiconductor Devices and Circuits, Wiley, 1981. + more recent defect types 9/13/2011 6 Common Fault Models Single stuck-at faults Transistor open and short faults Memory faults PLA faults (stuck-at, cross-point, bridging) Functional faults (processors) Delay faults (transition, path) Analog faults
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/13/2012 for the course ECE 553 taught by Professor Ece553 during the Winter '08 term at Wisconsin.

Page1 / 4

Lecture_5 - 9/13/2011 Overview Motivation Fault Modeling...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online