Large panel, highly flexible multilayer thin film boards

A new production line for large panel multilayer thin film boards has been installed and is now on the way to get functional. The line allows the manufacturing of flexible HiCoFlex multilayers in the format of 24rdquo times 24rdquo. Thus larger sized panels and greater production capacity are now enabled. HiCoFlex is a technology for producing flexible multilayer circuits using the conventional thin film techniques. The multilayer is built-up on temporary rigid glass substrates by repetitive application of polyimide layers by a spin-on process and metal layers by a sputtering and if needed enforced by galvanic deposition. Via's to underneath conductor levels are opened by laser cutting. The steps (metal layer by sputtering - photolithographic and galvanic processes - polyimide layer by spin-on, drying and curing - via's opening) can be repeated several times, resulting in a multilayer structure. Assembling and bonding of the components and tests of the circuits are possible while the film is still sticking on the glass, avoiding handling problems of conventional flexprints. At the end the flex multilayer is released from the substrate making use of a special release layer. Applications of HiCoFlex multilayers are in the fields of high-density interconnect (HDI) technologies for sensors, industrial and medical micro systems. In addition, the unique combination of a flexible material with the electrical properties of a MCM-D offers new applications in the field of 3D-packaging. Application fields of such highly integrated modules are strongly growing areas like medical and health monitoring, both for implanted and non-implanted medical devices, sensors, portable and wearable electronic systems. In this paper the properties and features of these flex as well as some applications are discussed.