The Characterization of Whiskers Produced by Electromigration on Suspended Aluminum Linestripes
Abstract
Studies have shown that aluminum whiskers resulting from electromigration are as threatening to device reliability as void formation. Comparatively little research has been conducted to study their morphology or formation. This study generates whiskers on suspended aluminum tests stripes. The aluminum is evaporated onto 9 mil thick silicon wafers with a 5000 A layer of thermally grown silicon dioxide. Normal photolithography techniques are used to produce serpentine test patterns. The silicon substrate is chemically etched to produce aluminum stripes suspended on a thin layer of silicon dioxide. A current density of approximately 450,000 A/sq. cm is applied to induce electromigration. The whiskers are examined with a Cambridge MK II Scanning Electron Microscope and analyzed with a JEOL 2000FX Scanning Transmission Electron Microscope. The results of the analysis show that aluminum whiskers grow in a <110> direction along the crystal axis. Additional morphological observations reveal internal dislocations and mass accumulation beneath the stripe surface at the whisker's nucleation site.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 08, 1986
- Accession Number
- ADA179383
Entities
People
- Scott L. Linder
Organizations
- Air Force Institute of Technology