SYMPOSIA PAPER Published: 01 January 1978
STP27314S

Metallic Barriers for Protection of Contacts in Electronic Circuits from Atmospheric Corrosion

Source

The effectiveness of a variety of 1 to 2-μm-thick barriers in preventing the interdiffusion of copper substrates with gold overplates was investigated. These studies were carried out at both elevated (400 and 500°C) and low temperatures (100 and 175°C). In the high temperature range, of the materials studied, only the cobalt and cobalt-5 weight percent phosphorous were found to be effective barriers. Their effectiveness was comparable to that of the nickel-8 weight percent phosphorous barrier reported by Turn.

The low temperature results were anomalous in that the specimens annealed at 100°C show greater penetration than those annealed at 175°C. It is proposed that this temperature effect is related to the concurrent recrystallization of the gold overplate taking place to a larger degree during the higher temperature diffusion anneal. Thus, at the lower temperature the high density of grain boundaries characteristic of asplated structures is better preserved and leads to a larger overall (grain-boundary) diffusive flux.

Author Information

Marx, DR
Pennsylvania State University, Pa
Bitler, WR
Pennsylvania State University, Pa
Pickering, HW
Pennsylvania State University, Pa
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Details
Developed by Committee: G01
Pages: 48–57
DOI: 10.1520/STP27314S
ISBN-EB: 978-0-8031-4717-1
ISBN-13: 978-0-8031-0286-6