Russ
When I was dealing with the problem of micro BGA's and FinePitch components
we found that HAL surfaces can be produced with a surface flat enough to
satisfy the needs of fine pitch production. However, the boards had to be
plated in a brand new horizontal HAL machine which was quite expensive. I
don't think this equipment will be standard in near future. We had no
problems with NiAu and OSP's. The easiest PCB to work with where those with
a Solid Solder Deposition (SSD) finish. They where already fluxed with a
slightly sticky flux. With these boards we went so several companies who
had no experience in using FinePitch components in every place we had no
troubles in the production of a lot of 50 pieces. Sure this test is non
representative for a large scale production. But I think it shows that SSD
could be a valuable alternative to other production processes when things
are getting tough.
Best regards
Guenter