Phil,

While you may be able to get the copper to bond if it is clean enough and laminated soon enough after
cleaning, you will get a more robust bond using an "oxide treatment" or "conversion coating" of some sort.

For this reason, most fabrication specifications require use of an oxide treatment.  Almost all board shops
(at least every one that I am aware of) would use an oxide treatment even if it were not specifically
required.

Laminate manufacturers use an oxide treatment on the back side of the copper foil when they produce the
laminate.  They use the same treatment that is sold as "double treat" except only one side is treated --
the side that ends up on the inside of the laminate.

All the various coatings provide one thing that bare copper can not, that is additional tooth to promote
bonding at lamination.  Obviously, the more polished the copper surface is the less tooth one would expect
to find and the weaker the bond would be.





> Subject: Black Oxide, why bother?
> Date: Wed, 5 May 1999 10:49:09 -0700
> From: Phil Hersey <[log in to unmask]>
>
> I have found a cleaning system which removes only copper oxide and does not
> touch the underlying copper.  So, if I start with clean copper and laminate
> within 8 hours why would I need a conversion coating?  Epoxy bonds well to
> clean copper doesn't it (even if it is an "optical polish" surface)?
>
> Resp.
> Phil Hersey, Carson City Nevada USA

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################