|
Metal Properties
Selection Guide &
Tech Papers
•Metal Properties Selection Guide
•TMI Papers
 |
<< Return to Technical Papers Index
An Evaluation of Aluminum Wire Bondable Surfaces for Automotive
Lead Frame Applications
Philip W. Lees
Technical Materials, Inc.
Lincoln, RI 02865
Abstract: Aluminum inlaid into copper base metal has been
the material of choice for automotive lead frames connecting hybrid
and multi-chip modules to control circuits. The aluminum bond surface
provides for a wide process window with very high capability and extremely
low internal scrap. This is a significant point because quite often
the value of the electronics is at least two orders of magnitude higher
than the cost of the lead frame. The advent of global manufacturing
has increased pressure to investigate a more conventional and transportable
manufacturing technology for the bond surface. Electroplating processes
address this need. Silver electroplate is a suitable surface for gold
wire bonding. There are documented problems with Al wire bonds. Aluminum
wire will bond to clean silver surfaces. However, intermetallic compounds
formed at the interface are selectively corroded in humid environments
and may lead to bond interface failure. Electroless nickel phosphorous
(NiP) has been used as a bondable surface. Drawbacks with this process
include fixturing of parts, control of P content, and shelf life.
The purpose of this study is to revisit the Al-Ag bond integrity issues
and perform a preliminary assessment of the NiP bond surface produced
using the reel-to-reel electrolytic NiP process.
If you'd like to obtain the full-text version of this, or any other available paper, please fill out our contact form.
|
|
