Accession Number:

ADA256200

Title:

Electronics Reliability Fracture Mechanics, Volume 2. Fracture Mechanics

Descriptive Note:

Final rept. May 1987-Sep 1991

Corporate Author:

HUGHES AIRCRAFT CO EL SEGUNDO CA ELECTRO-OPTICAL AND DATA SYSTEMS GROUP

Report Date:

1992-05-01

Pagination or Media Count:

358.0

Abstract:

This is the second of two volumes. The other volume WL-TR-92-3015 is Causes of Failures of Shop Replaceable Units and Hybrid Microcircuits. The objective of the Electronics Reliability Fracture Mechanics ERFM program was to develop and demonstrate a life prediction technique for electronic assemblies, when subjected to environmental stresses of vibration and thermal cycling, based upon the mechanical properties of the materials and packaging configurations which make up an electronic system. The application of fracture mechanics to microscale phenomena in electronic assemblies was a pioneering research effort. The small scale made the experiments very difficult for example, the 1-mil-diameter bond wires in microelectronic devices are 13 the diameter of a human hair. A number of issues had to be resolved to determine whether a fracture mechanics modelling approach is correct for the selected failures specifically, the following two issues had to be resolved What fraction of the lifetime is spent in crack initiation Are macro fracture mechanics techniques, used in large structures such as bridges, applicable to the tiny structures in electronic equipment The following structural failure mechanisms were selected for modelling bondwire fracture from mechanical cycling bondwire fracture from thermal power cycling plated through hole PTH fracture from thermal cycling. The bondwire fracture test specimens were A1-1 Si wires, representative of wires used in the parts in the modules selected for detailed investigation in this program see Vol. 1 of this report 1-mil-diameter wires were tested in this program. The PTH test specimens were sections of 14-layer printed wiring boards of the type used.

Subject Categories:

  • Electrical and Electronic Equipment
  • Metallurgy and Metallography
  • Electricity and Magnetism
  • Mechanics
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE