Jonathan, Rivets are used as an alternative method to pin-lam. Tooling holes and rivet holes can be pre-punched in the raw laminate and used to register at I/L print or punched after D/E/S. The innerlayers are stacked on a fixture with pins and rivets inserted, by machine, to secure the alignment of layers to each other. The panel is then removed from the fixture, the remaining outside plies of b-stage and foil added and built up in a lamination book using separators and caul plates without holes/pins. After lamination, the panels must be tooled, using either x-ray or optical (after exposing internal targets) alignment. I can't quantify the difference between pin-lam and riveting in terms of dimensional consistency (shrinkage) or layer-to-layer. But, in earlier testing we saw no overall difference in registration on a particular 10 layer part when employing both methods side by side. Some of the benefits of riveting are : * No epoxy resin on panels and plates. * No expensive tooled caul and separator plates. * Thinner plates - more panels / press opening. * Less expensive material can be used for separators, i.e., aluminum, with a CTE closer to Cu than s.steel. * Tooling can compensate for misalignments. Some of the drawbacks : * Additional process step, floor space. * Additional equipment required for post-lam tooling. * Possibly more operator dependent in terms of layer-to-layer alignment. * Maintaining panel to panel alignment within a book. As far as the type of that rivets can be used for... we have been quite successful with fine line , thin core, tight tolerance up to 28 layers. ______________________________ Reply Separator _________________________________ Subject: Fab: Rivets in the lamination press Author: [log in to unmask] at INTERNET Date: 07/25/97 9:54 I've seen occasional submissions asking about rivets for holding multilayer boards together in the lamination press. Would someone fill me in on what's involved there? What is the purpose of the rivets? To constrain movement in the press? Can anyone quantify the benefit? What kind of tolerances are achieved? Are they aimed at improving layer to layer alignment within a panel, or affecting whole panel movement? Sideways shifting (translation/rotation) or inch per inch movement (shrinkage)? Are they used in addition to pins? Are they ever removed? What forms the composite locating system (for drilling, etc.) if not molded slots? How and when are the holes for the rivets put in the cores? Are rivets only useful in a certain pressure range? My impression was that cores will do what they want to do in the press and just deform against anything you try to put in their way to restrain them. Do you need to keep the pressure low to prevent this? What kind of products are rivets used on? Fine line, thin core, tight tolerance stuff or coarse, thick core, easy stuff? Thanks, Jonathan Whitcomb IBM Microelectronics *************************************************************************** * 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] * ***************************************************************************