I was just reading and got to thinking about PCB inner layer shifting. Now I realize that this can be caused by registration issues but here are the questions I can't readily answer: 1) Is it possible to cause inner layer shifting on only signal layers during the assembly operations or will this be seen in the PCB fabrication testing? 2) Can inner layers that create opens or shorts be latent or would the effect be seen immediately? 3) Would inner layers that do shift all shift the same way? In other words would I get the same opens/shorts? What would be the proportion of possible affected if not all? 4) Would the PCB stresses caused by lamination not be released prior to the PCB test or is there enough residual stress still in the PCB at time of assembly to cause an issue? 5) How would you know if you have inner layer shifting? I was just reading about etch back and some the test data related with the process, is this part of the driver to develop this process? Kathy Kuhlow 6980 Professional Parkway East Sarasota, FL 34240 Phone: 941-907-1000 ext 8248 Mobile: 320-267-5549 Email: [log in to unmask] --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------