An integrated circuit chip comprising a rewiring layer and welding bump structures and a making method thereof are disclosed. According to the integrated circuit chip, a first dielectric layer covers the upper surface and the side of a rewiring layer, and a second dielectric layer covers part of the upper surface of the first dielectric layer, the side of the first dielectric layer and part of a passivation layer. By arranging the first dielectric layer and the second dielectric layer, ion migration of the rewiring layer is blocked, and the short circuit phenomenon of different welding bump structures caused by deformation or splashdown can be prevented effectively.