Document Type

Thesis - University Access Only

Award Date

1996

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering

First Advisor

David W. Galipeau

Abstract

The potential for integrated circuit (IC) failure due to electromigration has increased markedly as the microelectronics industry has progressed towards sub-micron IC linewidths. There are numerous methods used to study electromigration, but all lack the ability to detect micro-void formation, the initial stage of electromigration. Two methods that offer potential advantages for the detection of micro-voids are surface acoustic wave (SAW) sensor measurements and atomic force microscopy. The extreme mass-sensitivity of SAW microsensors suggested a novel technique for the detection of micro-void formation and collapse as well as electromigration-induced mass transport. Atomic force microscope (AFM) images offer resolutions to the sub-nanometer range and therefore provided a tool to image micro-voids. The theory of SAW microsensors and electromigration-induced mass transport in drift-velocity structures was analyzed and used to develop a SAW electromigration sensor. Standard microelectronic fabrication techniques were used to fabricate both drift-velocity test structures and SAW electromigration sensors. A SAW oscillator circuit was fabricated and its stability determined. AFM images were extremely useful for studying the results of the electromigration process. Oxide formation during device fabrication, SAW oscillator instability, and SAW phase instability and sensitivity prevented SAW measurement of electromigration. Oxide formation on the drift-velocity test structure limited the ability to control the location of the electromigration process. Inadequate SAW oscillator stability and SAW phase instability were attributed to electromagnetic interference (EMI) caused by the drift-velocity test structure. Poor circuit packaging (size and EMI shielding) also contributed to poor oscillator stability. Suggestions for improvements in the SAW electromigration test structure and experimental setups were made.

Library of Congress Subject Headings

Electrodiffusion
Acoustic surface wave devices
Atomic force microscopy

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright