CAM

Etching defines what your PCB layout can and cannot achieve. Understanding the relationship between copper thickness, trace width, and spacing is not optional — it directly affects what your board costs and who can make it. How Etching Works — Downward and Sideways # The etchant does not only remove copper downward. It simultaneously attacks laterally — inward beneath the etch resist at the edges of every copper structure. This lateral attack is called undercut. The etch medium itself can be alkaline or acidic depending on the process — both attack copper selectively through the use of photo and metal resists as protective layers.