A process for fabricating a circuit board is provided. In the process, first, a circuit substrate including an insulation layer and at least a pad contacting the insulation layer is provided. Next, a barrier material layer is formed on the circuit substrate. The barrier material layer completely covers the insulation layer and the pad. Then, at least one conductive bump is formed on the barrier material layer. The conductive bump is opposite to the pad, and the material of the barrier material layer is different from the material of the conductive bump. Next, a portion of the barrier material layer is removed by using the conductive bump as a mask, so as to expose the surface of the insulation layer and to form a barrier connected between the conductive bump and the pad.