A substrate and a fabrication method thereof are proposed, with at least a check point being formed on the substrate. Prior to wire bonding and/or molding processes, cleanness of the substrate (cleaned by plasma) is determined according to color variation of the check point, so as to allow only cleaned and contamination-free substrates to be subsequently formed with bonding wires and encapsulants thereon. Thereby, qualities of wire-bonded electrical connection and encapsulant adhesion for the substrate can be assured, which helps prevent the occurrence of delamination between the encapsulant and the substrate. Moreover, the check point formed on the substrate is made during general substrate fabrication by using current equipment and technique, and in a manner as not to interfere with trace routability on the substrate; thereby, costs and complexity of substrate fabrication would not undesirably increased.