System and methods for optically measuring dielectric thickness in semiconductor devices

A method for optically measuring layer thickness in accordance with the present invention includes the steps of providing a first metal layer on a semiconductor device structure, providing a second metal layer on the first metal layer, forming a dielectric layer over the second metal layer and directing light onto the structure such that light reflected from a surface of the dielectric layer and a surface of the second metal layer create an interference pattern from which the dielectric layer thickness is measured. A system for optically measuring layer thickness includes a semiconductor device to be measured. The semiconductor device includes a first metal layer, a second metal layer disposed on the first metal layer, the second metal layer having an arcuate shaped top surface and a dielectric layer disposed on the second metal layer. A means for directing and receiving light is also included wherein light is directed onto the semiconductor device such that light reflected from a surface of the dielectric layer and a surface of the second metal layer creates an interference pattern from which the dielectric layer thickness is measured.