Excellent.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey
Sent: Wednesday, June 27, 2012 1:06 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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