Hi Werner,

if I got it right, one should design the landpattern the same size as the chip? That is for a 1206, the landpattern should be 120 mils overall length and 60 mils wide.

Then, I am wondering how can one inspect the workmanship, not to mention eventual rework?

And secondly, how could one control the height of the solder joint?

Regards,
Ioan

> -----Original Message-----
> From: TechNet [SMTP:[log in to unmask]] On Behalf Of Werner Engelmaier
> Sent: Monday, June 13, 2005 5:15 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] Ceramic MLCs and Leadfree, John Maxwell case?
> 
> Hi John,
> LF-solder are stronger, less ductile, and creep slower--all of these add up
> to higher stresses in LF-SJs; ergo higher flex crack sensitivity.
> For chip components I suggest getting rid of the fillets--they cause
> component cracking, increasing the solder joint height under CCs and CRs, and reflow
> soldering them.
> 
> Werner Engelmaier
> 
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