A method for forming a metal layer for an integrated circuit device includes forming a first conductive layer on an integrated circuit substrate. While forming the first conductive layer, a reflection index of the first conductive layer is monitored, and the formation of the first conductive layer is terminated when the reflection index of the first conductive layer reaches a predetermined value. More particularly, the first conductive layer can be an aluminum layer having a thickness in the range of approximately 500 Angstroms to 1500 Angstroms.