A fabrication process including the following steps for making a metal via structure is disclosed. A substrate with at least a metal pad configured thereon is prepared. A first dielectric layer configured on a top surface of the substrate has a first opening exposing a top surface of the metal pad. A patterned first photoresist having a second opening aligned with the first opening is applied on a top surface of the first dielectric layer. A first metal evaporation is performed to form a first adhesive layer conformably distributed on a wall surface of the first opening and on a top surface of the exposed area of the metal pad. A second metal evaporation is performed to form a first metal block. The first photoresist is stripped. The first metal block is flattened to have a top surface coplanar with a top surface of the first dielectric layer.