This is a new subject for me. Here is the abstract I found.
Anyone who has purchased the full report would know what the voltage to distance ratio would be for this to be a problem. Also the report may need to be updated to include the result from copper that is pre-stressed as was discovered in the Pb-free reliability reports, versus the standard copper.
See The Kirkendall effect of the Al-Cu couple with an electric field
by W Liu - 1998 - Related articles - All 4 versions
Kirkendall [1] demonstrated that an imbalance of intrinsic fluxes, the Kirkendall effect , leads to .... Kirkendall effect is produced as the copper diffuses ...
www.springerlink.com/index/W50W177225N47X51.pdf - Similar CAF Characteristics of FR-4 Printed Circuit Board(PCB) for Automotive Electronics
Document Number: 2009-01-1369
Date Published: April 2009
Author(s):
Jung Gi Han - Hyundai-Kia R&D Center
Won Sik Hong - Korea Electronics Technology Institute
Nochang Park - Korea Electronics Technology Institute
Abstract:
Recently, application of automotive electronics is rapidly on the increase and consumption of PCB(printed circuit board), which is applied to compose of electrical circuit, is also rising rapidly in automotive. During the term of guarantee in automotive, reliability of car electronics must to be verified and especially research of CAF(conductive anodic filament) characteristics to have an influence on insulation degradation of PCB is demanded. CAF is different with electrochemical metallic ion migration. CAF is generated at the anodic Cu(copper) interlayer and grow in the direction of cathode Cu interlayer, finally lead to short failure between multiplayer of automotive electronics. Thus, in this research, CAF characteristics is quantitatively evaluated and compared with raw materials of FR-4 PCB, respectively. From these results, failure mechanism and a preventive measure is showed. Consequently, this research is expected to contribute to improve the reliability of automotive electronics.
John Goulet
MFG/Process Engineer
----- Original Message -----
From: "Randall L Bock" <[log in to unmask]>
To: [log in to unmask]
Sent: Tuesday, January 19, 2010 11:18:28 AM GMT -05:00 US/Canada Eastern
Subject: Re: [TN] TI MSP Early Life Failure?
Do not have an answer to your question, but Warner was getting worried. TechNet is alive..
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Chris Mahanna
Sent: Tuesday, January 19, 2010 11:13 AM
To: [log in to unmask]
Subject: [TN] TI MSP Early Life Failure?
Hello Technet,
We are working on a failure analysis of a battery operated remote sensing device. Failure is linked to 500ohm short power/ground. The assembly experiences at least (2) 255C reflow thermal excursions. Failure manifests at ~6 months.
Slicing/dicing isolation yielded: breakdown between two vias (17 mil spacing) and/or MSP input impedance. Beyond that, original evidence is lost.
We are working the CAF theory, however reproduction of the problem is proving difficult, possibly due to the low number of opportunities on the actual board.
For those of you who know that I'm pushing for placement of (the new) CAF coupons on panels, yes this is our most recent example of the problem.
I would like to get feedback on the possibility that it was the microcontroller instead...
TI MSP430F1612
Level-3-260C-168 HR
Thanks!
Chris Mahanna
Robisan Laboratory Inc.
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