Patent ID: 7463355

Claim:
A system for simultaneously measuring optical constants (n, k) and thickness of a thin film formed on a substrate, comprising: a first light source that emits light that is directed at an oblique angle toward the thin film; a polarizer that disposed at the oblique angle between the first light source and the thin film; a first detector disposed to detect light derived from the first light source that is reflected from the thin film that is disposed at an oblique angle that is complementary to the oblique angle that the light is incident upon the thin film; an analyzer disposed at the complementary oblique angle between the first detector and the thin film; a second light source that emits light that is incident at a normal angle upon the thin film; a second detector disposed to detect light derived from the second light source that is reflected from the thin film; and a computer coupled to outputs of the first and second detectors that implements an algorithm that simultaneously measures the optical constants (n, k) and the thickness of the thin film using multi-angle differential polarimetry by computing ratios of the change in ellipsometric parameters and reflectance of the thin film relative to the substrate.