The base of the motherboard is made of fiberglass fabric sheets. Manufacturers add epoxy to the sheets and stack them on top of one another until they are thick enough to support the board. Next, they apply copper sheets to both sides of the base. Photo-resist is applied to the board and most of the copper is etched away to create the board's circuitry.
After producing several different boards with etched copper circuitry, manufacturers layer the boards on top of each other. A typical motherboard has six different layers. To keep the circuitry separate, a material called "prepeg" is inserted between each sheet. After layering the boards, the board is coated in copper and tin.
