Circuits on thermoplastic materials

A semi-additive circuit uses an unclad base material. After seeding, the surface is covered with a very thin layer of copper and the subsequent processes are very much the same as used in the making of printed circuit boards by the subtractive method, the basic difference being that only about 2 microns of copper are etched away compared with 17 microns for half ounce copper and 35 microns for one ounce copper. This leads to a considerably saving in time and materials. Using the semi-additive process, printed circuits can be produced on thermoplastic base materials which may be moulded into various shapes to suit the designer's requirements.