Printed circuit board Manufacturing Photo-resist
Most circuit boards are made with a light sensitive covering, for photolithography. This covering is sometimes called photo-resist. The covering reacts with light. Then the circuit board and covering are put in a developer. Developer is a liquid that dissolves the covering that was exposed to light. Then the board is put in an etchant. An etchant dissolves the copper that is not covered by the covering. Some companies also use this method. It is expensive per board, but very cheap to set up in the beginning.