MID Fabricated by Ultrasonic Processing

Electronic circuit boards have been fabricated in cycle times of a few seconds by ultrasonic fabrication. A stack of thermoplastic polymer foils with a copper layer, 20 μm in thickness, on top is transformed into a polymer carrier with separated conductor paths. This process is accomplished in cycle times of a few seconds and the required equipment is just a commercially available ultrasonic welding machine and a metal tool micro patterned, e.g., by milling.Since soldering is often not possible on a thermoplastic carrier, electronic components are joined to the conductor paths by ultrasonic welding. This is achieved by employing an anisotropic conductive foil containing metal particles providing the electrical contact normal to the foil and showing no conductivity in lateral direction. The anisotropic conductive foil also serves as glue between circuit board and electronic components.