From the tone of your email I get the impression that "
Richard,
From the tone of your email I get the impression that "BS" stands for
"Biased Stadem".
Fortunately, I know that your biases and my biases for IAg are founded
on real experience rather than rumors.
Regards,
George
George M. Wenger
Andrew Wireless Solutions
Senior Principal FMA / Reliability Engineer
40 Technology Drive, Warren, NJ 07059
(908) 546-4531 [Office] (732) 309-8964 [Cell]
[log in to unmask]
-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]]
Sent: Thursday, December 04, 2008 5:55 PM
To: (Leadfree Electronics Assembly Forum); Wenger, George M.
Subject: RE: [LF] Pro's and Con's of using Immersion Silver
I have to agree with what George said, but I can tell you that I have a
lot of experience with IAg boards, including super large ones that were
40" wide by 24" high and weighed 75 lbs. I have never had any issues
with it, and I have been an advocate for IAg for many years. However, I
understand that sometimes ENIG is the proper choice, and also
applications where neither one is practical.
As far as why many still use ENIG, here are some reasons I have been
told:
1. Because it is easier to solder to gold (BS, you don't solder
to the gold)
2. Because you get a better solder joint soldering to gold (BS,
with ENIG you are soldering to the nickel
underneath)
3. Because you need the added strength of the nickel plating in
the vias (in some applications, true).
4. It costs more, so it must be more reliable (Absolute BS)
5. It performs better in high impedance, high frequency circuits
than IAg (Absolute BS, the opposite is in fact generally
true)
6. Well, we always have used ENIG, and we just boilerplate the
requirements from fab drawing to new fab drawing (I have had so
many design engineers tell me this)
7. We need the gold for contact switches or wirebonding purposes
(true).
8. IAg does not solder well after 6 months (BS, it is easier to
form a good SJ with the copper underneath provided you have
packaged and stored the IAg boards properly in the first place).
9. We have always used ENIG from a particular PWB vendor without
any issues, and are hesitant to change. (That's a darn good
reason!)
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Wenger, George M.
Sent: Thursday, December 04, 2008 3:52 PM
To: [log in to unmask]
Subject: Re: [LF] Pro's and Con's of using Immersion Silver
Tim,
We've used IAg since 1996 and have had extremel
Tim,
We've used IAg since 1996 and have had extremely good results. You're
probably going to get all kinds of answers about solderability, storage,
and long term reliability but my short answer is that from my
prospective the solderability and long term reliability is better than
ENIG and the storage can be as good if you be careful where you store
it.
As for the question of why there are still a lot of companies using
ENIG, the best answers will come from those who are still using it. It
is a good, flat solderable surface and as long as you don't run into a
problem with solder joint failures there is probably not a lot of reason
to change to an alternative. However, I assume there are also lots of
companies who had problems with ENIG that have switch to IAg.
Regards,
George
George M. Wenger
Andrew Wireless Solutions
Senior Principal FMA / Reliability Engineer 40 Technology Drive, Warren,
NJ 07059
(908) 546-4531 [Office] (732) 309-8964 [Cell] [log in to unmask]
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Tim Boyer
Sent: Thursday, December 04, 2008 3:16 PM
To: [log in to unmask]
Subject: [LF] Pro's and Con's of using Immersion Silver
Currently we use Immersion Gold for our ROHS boards.
We are looking into changing to Immersion Silver.
What differences are there in solderability, storage, long term
reliability, operating temperatures,
etc?
Why are allot of companies still using Immersion Gold over Nickel for
ROHS boards?
Tim Boyer, CID+
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