Engineering topics
Publications and source records attributed to Nowakowski, M. F..
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 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
Power transistor reliability against second breakdown, locating breakdown by IR fast scan microscope and measuring breakdown voltage
Semiautomated X-ray television for nondestructive testing and inspection
Transistor second breakdown location, size and temperature detected and analyzed before failure by high resolution IR microscope
External visual inspection criteria for semiconductor devices