Folks,

Pete is correct.  I never said lead-free implementation was a grand success.  These were Rob's words in his blog post (http://www.designnews.com/author.asp?section_id=1389&doc_id=231199&f_src=designnews_gnews).  

I have said repeatedly that adequate lead-free reliability has been demonstrated for consumer products like mobile phones, PCs, portable electronics with service lives less than 5 years.  This level of reliability has been demonstrated in numerous studies and more importantly with field data.  Vahid Goudarzi, of Motorola, stated that field reliability of lead-free assembled mobile phones has been equal or better than leaded assembly units.  His data go back to 2001 (not 2006, Motorola started early for reasons discussed below).

The reason Motorola shipped early with lead-free products is due to the fact that lead-free solder does not spread as well.  Because of this poorer spreading, Motorola was able to decrease lead spacings without getting shorts, thus increasing the amount of electrical function in a smaller space.  Since increased function in a smaller space is the defining attribute of portable electronics, the importance of this lead-free advantage cannot be overstated.  Admittedly, lead-free's poorer wetting is a challenge in other regards, especially hole fill in wave soldering, but the Motorola Droid X2 could not be assembled with leaded solder, there would be too many shorts.  Since the packaging density of the iPhone and similar devices is on a par with the Droid X2, I suspect this statement is true for most mobile products.

I have also repeatedly stated that lead-free reliability for long term service, mission critical devices has not been demonstrated.  As a result, these types of devices should not consider lead-free solder at this date.

I regularly discuss these topics in my blog (http://blogs.indium.com/blog/an-interview-with-the-professor).  The most recent post shows a striking photo of leaded solders too good spreading for portable electronics.


Cheers, 

Ron 

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