Patent ID: 8860937

Claim:
A system configured to determine one or more characteristics of one or more structures formed on a wafer, comprising: an illumination subsystem configured to direct light to the one or more structures formed on the wafer, wherein the light comprises ultraviolet light, visible light, and infrared light, and wherein the one or more structures comprise at least one high aspect ratio structure or at least one large lateral dimension structure; a detection subsystem configured to generate output responsive to light from the one or more structures due to the light directed to the one or more structures; and a computer subsystem configured to determine one or more characteristics of the one or more structures using the output, wherein the computer subsystem is further configured to use the output responsive to the infrared light from the one or more structures to determine one or more characteristics of a bottom portion of the at least one high aspect ratio structure and to use the output responsive to the visible and ultraviolet light from the one or more structures to determine one or more characteristics of a too portion of the at least one high aspect ratio structure.