Process for making PCBs with insulating material between tracks

摘要

In a process for making a PCB conductive tracks 5 are formed by etching a conductive layer joined by adhesive to a substrate 1, the gaps between the tracks are filled with resinous insulating material 7 which also flows over the tracks and the material 7 is abraded so as to leave flush the upper surfaces of the tracks and the intervening filler, the PCB is cooled during the abrading step so that the material 7 is kept below its glass transition temperature. As a final step a solder-resistant mask may be applied to the upper face of the PCB so as to expose only small areas of the tracks. A double sided PCB may be formed by applying these steps to both sides of a substrate.