Patent ID: 8334981
Filing Date: 2012-12-18
Classification: G01B

Abstract:
1. A method of orthogonal-polarization Mirau interferometry, comprising the steps of: splitting a focused narrow-band or broad-band incident light into a reference light and an inspection light by using a beam-splitting module wherein the polarizations of the reference light and the inspection light are orthogonal to each other; projecting the inspection light onto a measured object, thereby forming an object light containing information corresponding to the surface profile of the measured object; combining the object light and the reference light into a combined light by using the same area of the beam-splitting layer with the polarizations of the object light and the reference light being orthogonal to each other; and modulating the polarizations of the object light and the reference light such that the object light and the reference light interfere with each other and the intensity of the object light and the intensity of the reference light are close, wherein the beam-splitting module further comprises: a non-polarization beam-splitting layer, for splitting the focused narrow-band or broad-band incident light into the reference light and the inspection light; a first polarization layer, for modulating the inspection light into a polarized light with a specified polarization; and a polarization-reflective layer, for reflecting and polarizing the reference light so as to make the polarization of the reference light orthogonal to the polarization of the inspection light.