Re: [SI-LIST] : copper finish/copper oxidation on pcb

About this list Date view Thread view Subject view Author view

From: HaroldLSJ@aol.com
Date: Tue Aug 29 2000 - 21:37:00 PDT


Pat, Craig,

I believe you are referring to OSP (organic solderability preservative).
Typical OSP's are rosin or resin bases (see patent 5,176,749 granted 1993) or
thermally stable azoles (see patent 4,373,656 granted 1983). One alternative
is the use of benzotrizole followed by a solvent or water based preflux (see
"Enhanced SMT Solderability with No HASL", IPC Technical Review, Dec 1990).
A third alternative is PADS (plasma assisted dry soldering) (this is still a
new technique and I don't know any board house that has started using this
method -- if anyone knows one please post it).

Harold L. Snyder, Jr.
Scientist & Consultant

Begin Included Message:
===========================
> Subj: RE: [SI-LIST] : copper finish/copper oxidation on pcb
> Date: 8/29/2000 8:02:32 PM Central Daylight Time
> From: zabinski.patrick@mayo.edu (Zabinski, Patrick J.)
> Sender: owner-si-list@silab.eng.sun.com
> Reply-to: zabinski.patrick@mayo.edu (Zabinski, Patrick J.)
> To: deibele@fnal.gov, si-list@silab.eng.sun.com
>
> Craig,
>
> I suggest you look into OSB (organic S?? B??) coating. It is a
> very-thin coating over coppper that effectively vanishes with
> any form of heat/chemicals. In this way, it will not oxidize,
> leaving your copper clean. Then, a simple spray solution will
> remove it.
>
> Sorry I don't know the actual name, but all board vendors we've
> deal with offer it, and they'll be able to tell you the details
> on how to remove it when desired.
>
> Pat
>
> > Hi,
> >
> > I have an application where I cannot use a solder mask...I
> > require that the copper be exposed. My main problem is that
> > after board assembly, no matter how careful I assemble to
> > boards (wearing rubber gloves, cleaning the copper), smudges
> > and slight oxidation occur to the copper.
> >
> > So, after I assemble a board, I would like to rinse the
> > copper with a mild acid that would remove the oxidation
> > layer. Does anyone have any experience doing that?
> > What/where should I try to procure this acid? Or am I
> > offbase in even thinking of using an acid?
> >
> > Curious,
> >
> > Craig Deibele
===========================
End Included Message.

**** To unsubscribe from si-list or si-list-digest: send e-mail to
majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
****


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Tue May 08 2001 - 14:29:23 PDT