Seems like everything I pick up these days has an article about BGA's and
how they will revolutionize the world. From the talk at the shows, the
magazine articles, and they equipment brochures I've read in the last year
or so, you'd think they were flooding the market.

I'm still skeptical.

They have a benefit, and for pin counts above 200, some real practical
advantages in processing and reliability.

We have built exactly 8 units here with PBGA's. All protos, done by hand on
one new board design here. They worked easily enough. We have discussed
putting three in-house designed ASIC devices in this package. All three are
still in QFP's - the reason is that the cost is incrementally about 30%
higher for the devices we have actually quoted packaged in a PBGA vs. a
QFP304 (about $65 vs. $50).

Until we see the semiconductor manufacturers offering this wonderful,
fantastic package at a similar cost, I doubt anyone can argue sucessfully
how to save $15 per board by going to a BGA. I do not understand why it is
so much more expensive than conventional molded packages with stamped
leadframes, but it is in our experience.

Of course, it is extremely difficult to make, handle, place, and solder
these monster QFP's with 0.5 mm pitch, I do not like them, either. It's
just that I think we can put them down for a good deal less than $15
apiece.

If we were Compaq, and buying a few hundred thousand a month, I am sure
we'd be getting better price. I understand they are getting all their high
pin count devices in PBGA's now. Maybe they will drive this market, and
things will change soon.

This is an interesting development in the field of IC packaging, and it has
merit. For many of us, it is not yet a significant issue, and it may be a
number of years before it is commonly used by the broad spectrum of circuit
board designs.



cheers,

Jerry Cupples
Interphase Corporation
Dallas, TX
http:www.iphase.com