Doug, I thought the purpose of inner layer oxide was to increase the bond between the copper and the epoxy. The epoxy itself should protect the copper from corosion. Have I been wrong all these years. Why did I do all those bond tests on oxides with different crystal structures? Chuck Brummer [log in to unmask] wrote: > Rudy, > One of the things I saw whilst at CSL was that we would sometimes see > corrosion on inner layer traces when they were placed very close to the > edge of a board. If the panels had been scored rather than routed, as was > the case, the mechanical flexing would open the edge of the laminate, or > the rough edge would allow moisture ingress, such that the inner layers > could corrode. So one thing I would look at would be the flexibility of > the oxide. I would also look at how well oxide coated inner traces, placed > near the edge of the board, resisted corrosion. If you are convinced that > the vendor has adequate inner layer cleanliness before lamination, then you > might want to use some external contaminant source, such as salt spray/fog > testing or some of the mixed flowing gas tests done at UL. Susan Mansilla > had a good test and would be dramatically faster and easier than the tests > I suggest, but probably would not address the corrosion issues. > > The whole point of the inner layer oxide is protect the metal. > a. Does the oxide interfere with good plating in vias? > b. Does the oxide have sufficient flexibility to protect the metal in high > G or high shock environments? > c. Does the oxide have sufficient chemical resistance to protect the metal > against corrosive elements? > > Doug Pauls > Rockwell Collins > > --------------------------------------------------------------------------------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------