Calibration of a small angle X-ray scatterometry based metrology system
US10481111B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 2017 |
| Grant date | Nov 19, 2019 |
| Priority date | — |
| Expiry date | May 10, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG21K1/067
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and systems for calibrating the location of x-ray beam incidence onto a specimen in an x-ray scatterometry metrology system are described herein. The precise location of incidence of the illumination beam on the surface of the wafer is determined based on occlusion of the illumination beam by two or more occlusion elements. The center of the illumination beam is determined based on measured values of transmitted flux and a model of the interaction of the beam with each occlusion element. The position of the axis of rotation orienting a wafer over a range of angles of incidence is adjusted to align with the surface of wafer and intersect the illumination beam at the measurement location. A precise offset value between the normal angle of incidence of the illumination beam relative to the wafer surface and the zero angle of incidence as measured by the specimen positioning system is determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.