In a message dated 7/28/2005 11:44:13 A.M. Eastern Daylight Time,  Jeffrey.Bu
[log in to unmask] writes:

Does  anybody out there have Board surface recommendations for a RoHs
process  ?




____________________________________


I'd recommend Pb-free HASL:
    *   far-better planarity than it's lead-based counterpart, appropriate
through  20-mil pitch.
    *   no embrittlement possibilities like ENIG,
    *   solder to copper instead of nickel as with ENIG (and all that
implies)
    *   cheaper than ENIG
    *   excellent shelf life
    *   can be reworked
    *   doesn't introduce 3rd/4th metals to your solder joint as with ENIG
    *   isn't banned by the Aerospace industry like immersion silver
    *   can be retrofitted in pre-existing HASL equipment at a fraction  of
the cost to installing silver / tin / ENIG / OSP lines.
    *   has reduced handling sensitivities versus OSP, TIN or SILVER
    *   is appropriate as a final finish, whereas no SILVER or OSP
manufacturer warrants immersion processes as a final post-assembly  finish.
    *   ...and despite Urban Legends, lead-free HASL solder is available in
operating temperatures suitable for 140-deg. FR-4.
Many veteran process engineers still find nothing solders like solder, and
there's good reasons for their position. But I'm hoping you want more  than
anecdotes so write-back if you'd care to pursue Pb-free HASL further.

Cheers!

ROBERT LAZARA
VP, Marketing & Tech Support

Tel: (800) 560-9457
Fax: +01  603.880.7975



=Circuit  Connect=


UL Listed  -  ISO Registered  -  SMTA  Member  -  IPC Member  -  EPA Partner
-  RoHS  Compliance

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