The increase in the need for multilayer printed circuit boards with more than two, four and especially more than six layers of copper has been concurrent with the adoption silkscreen of surface mount technology. "Through holes" components are assembled by their legs passing through the board and glued to the pads on
boards, layers of material are laminated together in an alternating sandwich: copper, substrate, copper, substrate, copper, etc.; each layer of copper is etched silkscreen and any internal sleepers (which will not extend to both outer surfaces of the finished multilayer board) are plated before the layers are laminated together. FR-4 epoxy glass is the most common
indicator silkscreen for the components on the PCB. Graphics and text on a circuit board's PCB are usually printed with a non-conductive permanent epoxy ink. The color is usually white, although other colors are available: yellow, black, blue, red. Screen printing is used to render useful information on the PCB board that can