Closed-loop control of X-ray knife edge
US10386313B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 2017 |
| Grant date | Aug 20, 2019 |
| Priority date | — |
| Expiry date | Mar 21, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2223/0563
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for X-ray scatterometry includes an X-ray source, which directs an X-ray beam to be incident at a grazing angle on an area of a surface of a sample, and an X-ray detector measures X-rays scattered from the area. A knife edge is arranged parallel to the surface of the sample in a location adjacent to the area so as to define a gap between the surface and the knife edge and to block a portion of the X-ray beam that does not pass through the gap. A motor moves the knife edge perpendicular to the surface so as to control a size of the gap. An optical rangefinder receives optical radiation reflected from the surface and outputs a signal indicative of a distance of the knife edge from the surface. Control circuitry drives the motor responsively to the signal in order to regulate the size of the gap.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.