Method for forming aluminum metal gate

The invention relates to a method for forming an aluminum metal gate. The method comprises the following steps of: providing a semiconductor substrate, wherein a sacrificial oxide layer, a dummy gate and spacers are formed on the semiconductor substrate in turn, the spacers are positioned on the semiconductor substrate on the two sides of the dummy gate, and interlayer dielectric (ILD) layers are formed on the semiconductor substrate on the two sides of the dummy gate and on the two sides of each spacer and flush with the dummy gate and the spacers; removing the dummy gate and the sacrificial oxide layer to form a groove; forming an aluminum metal layer on the ILD layers, and filling the groove; grinding the aluminum metal layer until the ILD layers are exposed; and performing anti-corrosion treatment on the surface of the aluminum metal layer to form the aluminum metal gate. By the method for forming the aluminum metal gate, the surface of the aluminum metal gate can be prevented from being corroded, so that the resistivity of the aluminum metal gate is ensured, and the electrical property and reliability of a semiconductor device are improved.