For decades, standard printed circuit boards where made with a rigid substrate. During the designing of the product, specifications had to take into account the rigid nature of the printed circuit board to ensure there was adequate room for it as well as for all related external connections and the enclosures. As technology advanced and electronics became thinner, lighter and crafted into various shapes, printed circuits boards needed to become more flexible to fit around components and moving parts. Flexible printed circuit boards are desirable in a wide range of industries, including aerospace and medical applications, as copper etching allows for the excess materials to be removed so the copper traces can be further defined on the circuit.
Methods Used When Etching Copper
When etching the copper on printed circuit boards, the copper clad substrate will undergo various techniques to remove the excess materials while leaving the desired copper behind. Two common techniques are mechanical etching and chemical etching. Mechanical etching involves using special machine tools to chip away strips of copper from the pad and trace boundaries. Chemical copper etching involves submerging the copper clad substrate into a corrosive liquid.
Chemical Copper Etching Procedure
Since copper can be resistant to a range of different liquids, a suitable etchant chemical is chosen. Before submerging the circuit board, the copper traces must be protected from the corrosive etchant. An etching resist is applied as a thin dry layer. This etchant resist is only applied to the desired copper that should remain on the printed circuit board. The printed circuit board is then submerged entirely into the liquid as the copper that is unprotected is removed.
Benefits of Chemical Etching to Flexible Circuit Boards
Since the entire circuit board is submerged into the chemical etchant, this process ensures that all the undesired copper is removed. This method improves the accuracy of the etching. In addition, the manufacturing process can be simplified when performing high production line runs of printed circuit board outputs when creating large quantities of the desired product. A manufacturer has greater control of the etching process.
When it comes to etching copper for flexible printed circuit boards, deciding on the right method can ensure that the procedure is carried out with the best results. Then you can decide on the right materials and chemicals that can be used that is economical for your operations while providing the flexible printed circuit boards that are right for the applications.