| abstract |
(57) Abstract: The disclosed flexible multilayer printed circuit board (10) is an interconnected adhesiveless laminate in which conductive adhesives (70, 80) are generally superposed. You are using (35,45,55). In one embodiment, these adhesiveless laminates (35,45,55) include relatively thin conductive layers (20,22,24,26,27,28) and metallized through holes (32,42, 52) and has high peel resistance. These metallized through-holes (32, 42, 52) preferably have a thickness of up to about 25 microns and are capable of withstanding the multi-layer assembly process. As a result, high flexibility, reliability, package density, and environmental resistance are available in thin multi-layer constructions. In a further embodiment, an adhesiveless dielectric layer (62, 64, 66, 67) is interposed between the adhesiveless laminates (35, 45, 55) to electrically insulate those portions. ing. These adhesiveless dielectric layers (62, 64, 66, 67) can define relatively small openings therein, thus providing greater package density for multilayer printed circuit boards. |