Patent ID: 9052190
Filing Date: 2015-06-09
Classification: G01B

Abstract:
1. A method of providing high accuracy inspection or metrology in a bright-field differential interference contrast (BF-DIC) system, the method comprising: creating a first beam and a second beam from a first light beam, the first beam and the second beam having round cross-sections, and the first beam and the second beam forming first partially overlapping scanning spots radially displaced on a substrate; creating a third beam and a fourth beam from one of the first light beam and a second light beam, the third beam and the fourth beam having elliptical cross-sections, and the third beam and the fourth beam forming second partially overlapping scanning spots tangentially displaced on the substrate; and scanning at least one portion of the substrate using the first partially overlapping scanning spots and the second partially overlapping scanning spots as the substrate is rotated.