Hi Technet!

Another one of those days.....

Here's my scenario:

I'm trying to design a large (18"X20"), thick (.120") complex (20+ lyr)
PWB which has two very large Land Grid Arrays (1500 pins ea.) requiring
hard nickel gold.

While the CAD routing is going on, my preference is to design the thing
using  nickel/gold as the surface finish to avoid many, many issues for
PWB mfg. We need it anyway for the LGAs.

I see boards like these (i.e. all nickel/gold finish) all over the place
when I visit board shops. Although I see some selective HASL with
nickel/gold too, NONE of the board shops want to do this and price it
accordingly.

HOWEVER, the assembly group I have to use has been using HASL for the
last 8 years but took 12 years to convert from plated reflowed tin/lead
to HASL ! I was the bozo that hung in there for the 12 years!

Nickel/gold would be a very convenient surface finish solution.

I don't have another 12 years fight left in me!

From the assemblers:

What are the SMT process differences between a HASL version (assuming it
could be built) and the nickel/gold version?


Thanks for anything that helps....

Gerry

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