Patent ID: 11965798
Assignee: APPLIED MATERIALS, INC.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 18:
19. A method comprising:
transmitting incident light through a first emitting optical fiber of a first set of optical fibers arranged around a center point of an optical bundle and a second emitting optical fiber of a second set of optical fibers arranged around the center point of the optical bundle, wherein the first set of optical fibers further comprises a first receiving optical fiber that is positioned at a pairing angle relative to the first emitting optical fiber around the center point, and wherein the second set of optical fibers further comprises a second receiving optical fiber that is positioned at the pairing angle relative to the second emitting optical fiber around the center point;
directing, through an achromatic lens of a collimator assembly, a first plurality of spectral components of a first light beam of the incident light transmitted through the first emitting optical fiber to a first portion of a substrate surface and a second plurality of spectral components of the first light beam to a second portion of the substrate surface, wherein the first portion is substantially the same as the second portion;
receiving, from a light detection component coupled to the optical bundle, a first plurality of reflected spectral components and a second plurality of reflected spectral components collected by the achromatic lens of the collimator assembly, the first plurality of reflected spectral components produced by the first plurality of spectral components directed onto the first portion of the substrate surface and the second plurality of reflected spectral components produced by the second plurality of spectral components directed onto the second portion of the substrate surface, wherein the first plurality of reflected spectral components and the second plurality of reflected spectral components are transmitted from the achromatic lens to the light detection component via the first receiving optical fiber of the first set of optical fibers; and
determining a reflectance of the surface of the substrate based on the first plurality of reflected spectral components and the second plurality of reflected spectral components.