Fiberoptically-coupled measurement system with reduced sensitivity to angularly-driven variation of signals upon reflection from a wafer
US10794763B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 11, 2020 |
| Grant date | Oct 6, 2020 |
| Priority date | — |
| Expiry date | Feb 11, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical system having an OAP mirror collimator is disclosed with a housing, an OAP mirror located within the housing and has an optical axis, a fold plane and a focal point. A fiber optical cable is coupled to the housing and has first and second optical fibers, each having an exit end that form a common end face of the fiber optic cable, wherein the fiber optical cable is rotationally and translationally aligned to the OAP mirror such that the common face is perpendicular to and centered upon the optical axis of the OAP mirror and positioned a fixed distance from the focal point, and wherein the optical axes of the first and second optical fibers are jointly angularly aligned to the fold plane, and the optical axes of the first and second optical fibers deviate from being parallel to the optical axis by no more than 0.15 degrees.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.