How about conformal coating using Humiseal?
Here's a white paper comparing the effects between bare copper and thick/thin Humiseal applications:
http://www.taconic-add.com/pdf/technicaltopics--effects-of-solder-masks-and-conformal-coatings.pdf
Ron Feyereisen
Continuous Improvement Mgr., CIT
www.sigmatronintl.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Larson, Mark
Sent: Friday, August 15, 2014 1:38 PM
To: [log in to unmask]
Subject: [BULK] Re: [TN] surface finish for "bare" copper
Importance: Low
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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