05-03-2013, 01:05 PM
INTRODUCTION TO VLSI TESTING
INTRODUCTION TO VLSI.pdf (Size: 986.46 KB / Downloads: 89)
Introduction
Integrated Circuits (ICs) have grown in size and complexity since the late 1950’s
– SSI, MSI, LSI, and Very Large Scale Integration (VLSI)
Moore’s Law: scale of ICs doubles every 18 months
– Growing size and complexity poses many and new testing challenges
Importance of Testing
Moore’s Law results from decreasing feature size (dimensions)
– From 10s of μm to 10s of nm for transistors and interconnecting wires
Operating frequencies have increased from 100 KHz to several
GHz
Decreasing feature size increases probability of defects during
manufacturing process
– A single faulty transistor or wire results in faulty IC
– Testing required to guarantee fault-free products
The VLSI Testing Process
Verification Testing (also called Design Verification)
– Verifies correctness of design and test procedure
– More common to correct design than test procedure
– Functional test, AC and DC parameter test
Manufacturing Testing
– Factory testing of all manufactured chips for parametric faults and for random
defects
Reliability Testing
– Reliability testing guarantees the reliability of product
– Various higher power supply, increasing test time and high temperature
Acceptance Testing (incoming inspection)
– Customer performs tests on purchased parts to ensure quality
Test Generation
Goal: find efficient set of test vectors with maximum fault
coverage
Fault simulation used to determine fault coverage
– Requires fault models to emulate behavior of defects
A good fault model
– Is computationally efficient for simulation
– Accurately reflects behavior of defects
No single fault model works for all possible defects