Patent ID: 9360369
Filing Date: 2016-06-07
CPC Classification: G01J,G01N

Claim Text:
1. A system for determining average ellipsometric parameter values determined from two locations (PT 1 ) (PT 2 ) on a reflective surface of a planar or non-planar shaped object (CSO), comprising: a) a source (S) of, and a polarization state generator (PSG) for providing a polarized incident beam (IB) of electromagnetic radiation; b) a beam steering assembly (BSA) having top (TE) and bottom (BE) elements, and wherein said top (TE) and bottom (BE) elements each have first (FTO) (FBO) and second (STO) (SBO) openings therein, respectively; c) a stage (STG) for supporting said planar or non-planar shaped object (CSO); and d) a polarization state detector (PSD); said source (S) of electromagnetic radiation and polarization state generator (PSG) being positioned and oriented to direct a polarized incident beam (IB) of electromagnetic radiation toward and through said first top opening (FTO) in said beam steering assembly (BSA) top element (TE) such that it interacts with a first beam directing element (BDE 1 ) therewithin and is directed thereby to exit from said beam steering assembly (BSA) through said first bottom opening (FBO) in said bottom element (BE) thereof and impinge on a first location (PT 1 ) of said reflective surface of said planar or non-planar shaped object (CSO) placed on said stage (STG) for supporting it, from which first impingement location (PT 1 ) on said reflective surface of said planar or non-planar shaped object (CSO) said beam is then reflected toward and through said second bottom opening (SBO) in the bottom element (BE) wherein it encounters and reflects from a second beam directing element (BDE 2 ) which reflects and directs said beam back toward said planar or non-planar shaped objects (CSO) so that it impinges on a second location (PT 2 ) on the reflective surface thereof, which second location (PT 2 ) is offset from the location (PT 1 ) at which the incident beam (IB) first impinged thereupon, and from which second location (PT 2 ) said beam is reflected back toward and through said first bottom opening (FBO) and into said beam steering assembly (BSA) wherein it encounters, and is reflected from a third beam directing element (BDE 3 ) that reflects said beam through said second top opening (STO) in said top element (TE) of said beam steering assembly (BSA) and into said polarization state detector as an output beam (OB); said system further comprising computing system capability (COMP) for determining change in polarization state of said beam set by the polarization state generator (PSG) as a result of the double interaction thereof with said planar or non-planar shaped object (CSO), as detected by the polarization state detector (PSD), and providing average ellipsometric parameters therefore.