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May 2008

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Subject:
From:
Guy Ramsey <[log in to unmask]>
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Date:
Thu, 22 May 2008 07:49:17 -0400
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If we make the land narrower than the part and minimize the length, won't
that compromise both mechanical strength and solder joint life in a thermal
cycling environment? 

My experience with solder joint failure on chip components the joint cracks
down the face and under the part. If the height of the fillet is reduced the
time to failure will also reduce. No?  

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /*
Sent: Wednesday, May 21, 2008 5:51 PM
To: [log in to unmask]
Subject: Re: [TN] 0402 anti-tombstoning land pattern

Hi Dean,
Make the land pattern narrower than the component-I know, I know, tough to
do with 0402's as well as shorter thus producoing less of a fillet [which is
,of course, the root cause for the tombstoning]

Werner
Future workshops:
Reliability Issues with Lead-Free Soldering Processes, June 17, London
Interconnect Failures and Design for Reliability for PCB PTHs, June 17,
London Pb-Free Soldering Processes-Survival, Quality, Reliability, August
18, Orlando Reliability Issues with Lead-Free Soldering Processes, September
22, Schaumburg Failure Mode and Root Cause Analyses Reliability (Fatigue,
Brittle Fracture, ENIG), September 22, Schaumburg



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