Printed Circuit Boards

Layers of copper are used to make the multitude of circuits in a printed circuit board needed to keep electronic equipment small and efficient. In modern practice the substrate is built up in a number of layers, with a copper conductor layer added at each stage; a 1.6mm thick board might have 24 copper layers (including the outside surfaces). At the same time, the lead-pitch of components has reduced from 2.54mm to less than 0.5mm, making manufacture a high precision operation.