Hi Patty, I do not have a solution for your problem, but here are some questions that may help lead you to a solution. From your description, you have core materials on the outer layers? Are the 2 / 9 cores of the same core thickness and manufacturing lot? Were the 2 / 9 cores imaged and etched at the same time as the remaining cores? You may have a problem with your tooling system in the inner layer imaging operation. (a brief description of your system may help) Are you sure that this is a "shift" and not a "shrinkage" of the 2 / 9 images? If there is a shrinkage, you will need to compensate the 2 / 9 CAD data. If there is an image shrinkage of the 2 / 9 layers, the "shift" should be symmetrical around the center of the panel. Good Luck, Joe Brunetto Process Engineer Zycon Corporation ______________________________ Reply Separator _________________________________ Subject: FAB(Shifting Layers) Author: [log in to unmask] at corp Date: 3/20/97 12:47 PM We are experincing a reaccuring problem with our lamination process on 10 layer projects with the following stackup: 1. 1 oz copper on all 5 FR4 5 mil sheets; 2. 3 sheets of PGFK1080 2.5mil prepreg in each gap (total of 7.5mils each gap); 3. Grain of prepreg is in the same direction; 4. finished thickness 69 mils; 5. layers 2-4 & 7-9 are signal layers; 6. layers 5&6 are ground/VCC planes. Problem: We are consistently seeing layers 2 and 9 shift 3-4 mils more than the other layers (3:4, 5:6, & 7:8). Layers 3:4, 5:6, & 7:8 all align well with each other and the outermost sheets are shifted to the right by this 3-4 mils. Once layers 1 and 10 are imaged onto the drilled panel, they also line up well with the innermost layers (3:4, 5:6, & 7:8). We are losing panels due to annualar rings less than 2 mils on layers 2 & 9 (Mil-P-55110). We would appreciate any suggestions from those who have seen similar occurances. Patty Causey / Marty W. Sheppard Process Engineering Section email address: [log in to unmask] / [log in to unmask] Phone: (912) 926-9473(9632) *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************