An electrical chemical plating process is provided. A semiconductor structure is provided in an electrical plating platform. A pre-electrical-plating step is performed wherein the pre-electrical-plating step is carried out under a fixed voltage environment and lasts for 0.2 to 0.5 seconds after the current is above the threshold current of the electrical plating platform. After the pre-electrical-plating step, a first electrical plating step is performed on the semiconductor structure.