T. Gaylor: As you already know the main area of consideration in flex manufacturing is the material. The flex layers are an integral part of the construction and being a different material than the rigid layers, they change differently. Flex material is a film which by itself will shrink or grow depending on ambient conditions. Typically polyimide film, (Kapton) can change a mil per inch during processing. Some of this change can be compensated by scaling artwork, lamination cycles and lam materials and a big one, handling. Flex lamination requires a minimum of two lam cycles. The first is a coverlayer which is the insulating film in the flex area. This requires a conformal pad top and bottom in order to wrap the film around the conductor. This pad structure can consist of teflon glass cloth, tedlar, combination materials such a trade name product, "pacothane" or silicone rubber. The second lam cycle is the multilayer lamination which usually utilizes no-flow prepreg but could be constructed using an unsupported adhesive film such as Dupont's Pyralux. Again there can be different pad make ups. As with rigid boards there can be blind or buried via processing. The basic processing steps are the same for a rigid-flex as for a rigid board except that there are more of them, and it requires more tooling and front end engineering. Obviously equipment must be capable of handling thin cores. A typical double clad core will 1 oz cu/2 mil dielectric/1 oz cu which is less than 5 mils thick. The copper is usually dead soft, rolled and annealed which is where the handling problem comes in to play. Another area of concern is hole quality. There are different drill parameters required for rigid-flex and you would not typically stack more than one high on the drill. Desmearing in most cases requires plasma etch capabilities. These are a few of my rambling thoughts. If you would like to discuss off line give me a call. Regards, Ron Yanuszewski 603-337-1691 ______________________________ Reply Separator _________________________________ Subject: Flex Author: [log in to unmask] at !INTERNET Date: 1/3/97 12:18 AM I am curious, about the manufacturing of rigid/flex circuits. At our shop, we currently are not looking into any type of technology similar to this. I would like to know the considerations of working with a process such as this. I have heard that the lamination technique is somewhat different than conventional rigid multilayer processing. Also, another difference I have heard is the registrationing of the flex to rigid. I would appreciate if someone could give me some insight on rigid/flex processing. Thanks in advance T. Gaylor *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * 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 unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * 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] * ***************************************************************************