Actually, I think it gets into the nose as well. You can always smell it.
Bob K.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, June 27, 2012 3:33 PM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Frank,
Hogwash, like beauty, is in the eye of the beholder.
----Richard
Stadem
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey
Sent: Wednesday, June 27, 2012 2:26 PM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Bob,
Let's look at this with some common sense.
If we need to publish to be considered of value then we are in real trouble
as an industry.
No-clean residues can and do act as a dielectric.
The issue is we have no idea what the value is or would be as it varies with
the level of solids, organics, etc.
Can it be measured? Yes, it is measurable using a network analyzer with
probe.
I won't argue the high Z app being a conductivity issue but it brought a
problem to my attention and I have been working around it for long time now.
I learned a long time ago that those "soft and fuzzy" observations commonly
turn out to be reality when others all see the same type of problems.
We spend a lot of time trying to figure out what works, so do we also need
to spend time proving what doesn't?
For me if it don't work, either fix it or quit wasting time on it.
As for me, no-clean and RF don't work as well as wanted.
Does that mean you can't make it work, no but I'd rather not have to fight
the battle if I can help it.
Now this all may be hogwash and if so, I apologize for wasting your and
TechNet's time.
Just trying to help,
FNK
Frank N Kimmey CID+
Manager - PCB Design
Powerwave Technologies Inc.
Mobile - 916-670-0645
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Wednesday, June 27, 2012 12:04 PM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Frank,
I was happy to hear your personal attitude towards No Clean, but I was
hoping for something a little more analytical.
You mention the coating can and does act like a dielectric, but what value?
Is it close to FR4? Air? If someone takes a network analyzer can they detect
the presence of a glob of no clean left on a joint? I don't know, I am
simply asking.
The high Z application you mention where a no clean residue affected
performance, that is not a RF and dielectric issue, that is a conductivity
issue.
It is these "Soft and Fuzzy" personal observations that really don't count
in my book. Like Joe Friday: "Just the Facts Ma'ma". Anything else is, well,
potential hogwash.
Thanks,
Bob K.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey
Sent: Wednesday, June 27, 2012 2:06 PM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Okay Bob, let's discuss what happens with no-clean and RF.
No-clean leaves residue, commonly contaminants are contained in an inert
(after cure) material.
This coating can and does act as a dielectric.
As we know, dielectric changes impedance and impedance is what RF is all
about.
Now, where the real issue comes to play is that the residue left by no-clean
is not a consistent thickness and dielectric thickness is what has the
largest effect on RF impedance.
So if no-clean causes impedance changes/mismatch in some areas of the RF
path and not others then performance is adversely affected.
My first experience 20 years ago with this phenomenon was with high
impedance analog terraces were we saw a marked degradation in performance of
analog sensor circuits due to no-clean.
Now with higher powered RF circuits we see that any time loss is critical
(the key here is loss not power so it doesn't really matter how large the
signal is) no-clean does bad things to our signals.
Some of us use ENIG in our RF designs (I like the noble metal if I need to
leave exposed), others like IAg (silver is a great conductor) and others use
ISn (Tin works if you don't mind a whisker risk).
Bottom line is for best performance you need consistency and with no-clean
you don't get it as the left overs are not consistent across the circuit and
that DOES cause signal degradation.
At least that's what I have observed.
FNK
Frank N Kimmey CID+
Manager - PCB Design
Powerwave Technologies Inc.
Mobile - 916-670-0645
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Wednesday, June 27, 2012 10:37 AM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Richard,
I absolutely believe the ENIG issue is important. It was the No Clean part
of the question I was wondering about.
Bob K.
PS: I am about to hit send! :-)
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, June 27, 2012 1:25 PM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Sorry about that, "send" button was hit before I finished.
Ioan's original question was:
Can anybody point me towards papers talking about the influence of no-clean
soldering and ENIG on high frequency performance?
- With ENIG, your final surface layer is nickel, not gold.
- For very high frequency signals (generally considered to be above 1
gigahertz), electrical conductance takes place on the surface of the trace
(the nickel-plated part) due to the Hall or "skin" effect.
- Nickel's conductivity at frequencies above 1 Ghz is somewhat reduced,
compared with copper or gold. This is considered a "lossy" circuit
performance. There are many papers on this subject, including some from
Werner Engelmaier.
- I did not address losses through flux residues, only those regarding
signal loss in Db through nickel. But again, signal crosstalk and loss
through flux residue is well-documented.
I can assure you, Bob, it is NOT "hogwash".
-----Original Message-----
From: Stadem, Richard D.
Sent: Wednesday, June 27, 2012 12:10 PM
To: [log in to unmask]
Subject: RE: [TN] High frequency, ENIG and no-clean
Go back to Ioan's original question:
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Wednesday, June 27, 2012 11:46 AM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
Hi,
I have often wondered if this No-Clean Flux vs. RF issue was real or hog
wash so I tried to look at these links.
The first link must have changed pages, can anyone identify the new link or
subject description.
The second link was about the Ni plating vs. RF. I saw no reference to
flux or no clean. Did I miss something in my quick scan?
Thanks,
Bob K.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, June 27, 2012 11:31 AM
To: [log in to unmask]
Subject: Re: [TN] High frequency, ENIG and no-clean
http://www.taconic-add.com/mwg-internal/de5fs23hu73ds/progress?id=rG3E1oaXW1
http://athena-gatech.org/papers/staiculescu13.pdf
There are many more.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: Wednesday, June 27, 2012 9:00 AM
To: [log in to unmask]
Subject: [TN] High frequency, ENIG and no-clean
Dear Technos,
Can anybody point me towards papers talking about the influence of no-clean
soldering and ENIG on high frequency performance?
Thanks,
Ioan Tempea
Ingénieur principal de fabrication / Senior Manufacturing Engineer
<http://www.digico.cc/>
950 RUE BERGAR, LAVAL, QC, H7L 5A1 <http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
------------------------------------------------------------------------
<http://www.facebook.com/pages/Digico/277076778479>
------------------------------------------------------------------------
Lauréat Dunamis 2012 <http://digico.cc/dunamis-2012/>
Entreprise manufacturière / Gestion du capital humain
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