I can answer my own question, Benzotriazole is OSP
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Larson, Mark
Sent: Friday, August 15, 2014 2:36 PM
To: [log in to unmask]
Subject: Re: [TN] surface finish for "bare" copper
Anybody hear of "Benzotriazole"?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Friday, August 15, 2014 2:03 PM
To: [log in to unmask]
Subject: Re: [TN] surface finish for "bare" copper
Most RF antenna guys get a little too crazy about this. Up to about 10GHz I see a lot of ENIG used without complaint. If you want to see someone freak out, go ahead and put a conformal coat on the traces!
The original fabricator talking about bare copper may have been referring to a chromate anti-tarnish, which is often on the FR4 panels as delivered to the fab. That will hold up for quite a while also, but I don't know if it can be applied post-fabrication.
Nickel has poor RF performance. Ag oxidizes and will eventually look ugly, but the performance will probably be good for a long time, particularly with some anti-tarnish applied. Direct Au over copper might be something to consider.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce Koo
Sent: Friday, August 15, 2014 2:43 PM
To: [log in to unmask]
Subject: Re: [TN] surface finish for "bare" copper
(1) you need radar guy (2) my guess would be Ag.
just a guess.
jk
On Aug 15, 2014, at 2:37 PM, Larson, Mark wrote:
> Thank you but I guess I should have been more clear, there are no
> components and no holes on this board, it is an antenna board, I'm
> pretty sure, a couple decades ago perhaps, I had a similar situation
> and I ordered bare copper because that's what the engineer said, I got
> a call from the fabricator asking, no, make that telling me, we really
> didn't want that. Maybe finish isn't the right word, treatment
> perhaps, he said the copper could be treated with something that would
> prevent oxidizing. I think it was part of their normal process before
> applying HASL, but maybe with lead free it is no longer used.
>
> Maybe I could ask the question, what would you apply to prevent
> oxidation yet not affect the performance of the antenna in the several
> GigaHertz range.?
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce
> Koo
> Sent: Friday, August 15, 2014 1:04 PM
> To: [log in to unmask]
> Subject: Re: [TN] surface finish for "bare" copper
>
> agree with steve 100%. It also depend upon your assembly condition:
> flux activity, number of reflow, reflow profile, subsequent exposure
> to environment.... your design group should pick and choose the right
> finishing... not on the MFG floor... my 2 cents.
> jk
> On Aug 15, 2014, at 1:55 PM, Stephen Gregory wrote:
>
>> To add to Wayne's input, make sure you call out the right OSP
>> depending on the board technology...not all OSP's are the same.
>>
>> Steve
>>
>> Sent from my BlackBerry 10 smartphone.
>> Original Message
>> From: Wayne Thayer
>> Sent: Friday, August 15, 2014 11:28 AM
>> To: [log in to unmask]
>> Reply To: TechNet E-Mail Forum
>> Subject: Re: [TN] surface finish for "bare" copper
>>
>> OSP
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Mark Larson
>> Sent: Friday, August 15, 2014 1:12 PM
>> To: [log in to unmask]
>> Subject: [TN] surface finish for "bare" copper
>>
>> Hi,
>>
>> I've got a board that needs bare copper, many years ago I had this as
>> well and seem to recall that they can put on some kind of finish in
>> the process that does not leave it bare, but does protect it in the
>> processing of the board, and consequently does offer some protection
>> to the end user.
>> Anybody know what
>> that is or how I call it out?
>>
>> --
>>
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