What specific lead-free solder and pcb finish are you using?

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Cheryl Johnson
(303) 485-8829 home
(303) 809-5815 cell

 -------------- Original message ----------------------
From: "Thomas, Ian (Ian) %" <[log in to unmask]>
> Hi, Need some useful advice regarding a current design.
> I have a 12 layer FR4-370HR PCB, using stacked uvia's in pad which
> connect to planes on layers 2 & 3 which are flooded with no thermal
> relief.
> 
> We have seen no issue's with leaded assembly, but on transferring over
> to un-lead, we are seeing solder issue's with the BGA's (0.5mm pitch) on
> assembly
> and also rework issuse's with 90% of the other components (including
> 0402's) in getting them off the board.
> 
> Our first thoughts are to thermally relieve all the micro via's, but
> there are issue's because this may leave you with only one spoke on a
> pin in some areas.
> 
> Has any seen these issue's before?
> 
> Thank's in advance.
> 
> Ian
> LSI Technology (Mobility)
> 
> 
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