A circuit board which is suitable for carrying a chip and includes a substrate, a wiring layer and a solder mask is provided. The wiring layer is disposed on the substrate. The solder mask is between the substrate and the wiring layer. The solder mask has a chip area, a first opening and a second opening. The chip is suitable for being disposed in the chip area. The first opening and the second opening are respectively located outside two sides of the chip area that are adjacent to each other. The exposed parts of the wiring layer are used for identifying the relative location of the chip relative to the substrate.