Interferometric back focal plane scatterometry with Koehler illumination
US7061623B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 25, 2003 |
| Grant date | Jun 13, 2006 |
| Priority date | — |
| Expiry date | Aug 25, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95684
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interference spectroscopy instrument provides simultaneous measurement of specular scattering over multiple wavelengths and angles. The spectroscopy instrument includes an interference microscope illuminated by Koehler illumination and a video camera located to image the back focal plane of the microscope's objective lens while the path-length difference is varied between the reference and object paths. Multichannel Fourier analysis transforms the resultant intensity information into specular reflectivity data as a function of wavelength. This multitude of measured data provides a more sensitive scatterometry tool having superior performance in the measurement of small patterns on semiconductor devices and in measuring overlay on such devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.