Here's a thought: if all the tracks on a particular layer exhibit high resistance then likely that layer was either reworked or may have excessive oxide treatment. If, however, it is only the one track, then the problem is with the track itself. In the past we have found that a "dishdown" or nick or "mousebite", anything that reduces the volume of copper in a spot on the track is now a "bottleneck" that increases the line resistance. The other possibility is that a via in that net has low copper or copper voiding, which would also show up as high resistance on the net. To really root cause the problem would require doing some cross-sections ... Good luck and let us know what you find. Regards, Valerie R Sedlak <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 12/12/2004 08:54 PM Please respond to TechNet E-Mail Forum; Please respond to R Sedlak To: [log in to unmask] cc: Subject: Re: [TN] Resistive internal layers Phil: You are probably on the right track looking at the oxide. Since the assembly people are so fixed on the appearance of the oxide...(sigh), the fabricators may re-run panels down the oxide line if they come out initially looking "weird"... Each time they are run down the modern "alternate" oxide line, they lose about 2 microns (80 microinches) of Copper. Would this cause the problem you are seeing? Rudy Sedlak RD Chemical Company DUTTON Phil <[log in to unmask]> wrote: Hello Technetters, We have a multilayer board that is exhibiting higher than expected resistance on an internal layer track. The track is 0.006" and about 1.5 inches long, yet has a resistance of approximately 1 ohm. From what we can tell, the track has not been over etched. I'm wondering if anyone can shed some light on what could be the cause of this. I'm thinking that the layer may have had an excessive 'black oxide'treatment to promote adhesion. Is this possible? thanks, --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------