| 摘要 |
A method for forming a metal interconnection by a copper damascene process is provided to avoid defective via contact resistance and a via void by additionally removing a copper oxide layer formed on the surface of copper metal when a predetermined time interval has elapsed after a via contact is formed. An interlayer dielectric is deposited on a semiconductor substrate having a lower copper interconnection and a diffusion barrier layer. A photolithography process is performed to form a via contact hole and a trench pattern. A dry etch process and a wet etch process are performed to remove the diffusion barrier layer. When a standby time interval of 9 hours has elapsed after the diffusion barrier layer is removed, an additional wet etch process is performed to remove a copper oxide layer. A barrier metal and a copper layer are formed. A metal interconnection is patterned by a CMP process. The additional wet etch process can be made of the following steps. A soaking step is performed for 10-20 seconds by using a hydrochloric acid solution diluted by a volume ratio of 100:1. A soaking step is performed for 5-7 seconds by using a hydrofluoric acid solution diluted by a volume ratio of 100:1. A soaking step is performed for 4-6 seconds by using a TMAH solution diluted by a volume ratio of 110:30.
|
