Engineering topics
Publications and source records attributed to Villella, F..
Report documents behavior of discrete diodes and transistors in extensive power and temperature overstress tests. Thirty nine devices were tested in groups designated: (1) power overstress, and (2) and (3) temperature overstress. Results are of interest to users of tested components and engineers in conduction of similar tests.
Silicone resin of elastomer overcoatings are removed more quickly from microcircuit chips with hot concentrated sulfuric acid. Process takes few minutes as compared to day or two, using commercial solvents based on toluene, xylene, and like. Overcoatings are removed to expose circuit for failure analysis.
This paper presents data that has been generated within NASA, especially the Marshall Space Flight Center, concerning several failure mechanisms that have occurred with microelectronic packages. The types of packages that will be discussed are primarily flat packs with 14-24 exit leads that are composed of Kovar electro-deposited nickel and finally gold plated.
The current reliability problems related to electronic components and microcircuits are presented in this paper. Specific process controls, design, materials, application constraints, destructive testing, electrical tests, and procedures for implementation are recommended to improve the reliability of selected electronic components.
The purpose of this paper is to illustrate the failure mode caused by thermal deformation and how thermal deformation affects bond integrity. Wege bonding in small-signal transistors, microcircuits and LSI circuits is the subject of this work. Repeated switching of the devices between high and low power at a rate that allows thermal expansion and contraction in the interconnecting wire causes the wire to flex at the point of reduced cross-sectional area until finally the wire breaks due to metal fatigue. It was observed that the thermal deformation was related to many factors such as device power dissipation, current density in the wire, wi *e dress and length, thermal time constant and frequency of operation.
Fatigue in 1-mil diameter thermocompression and ultrasonic bonding of aluminum wire