Disclosure is a method for polishing a copper layer and a method for forming a copper layer wiring using the same. The method for polishing the copper layer is carried out through a CMP process by using slurry having a polishing rate of at least 10,000 Å/min. The method for forming the copper layer wiring includes a step of forming a sacrificial layer pattern having a trench on a substrate. Then, the copper layer is continuously formed on a sidewall of the trench, a bottom surface of the trench, and on the sacrificial layer pattern. Then, the copper layer is polished so as to expose a surface of the sacrificial layer pattern by using the method. The copper layer is effectively polished when the method is applied to a polishing process of the copper layer.