Approaches in first order scatterometry overlay based on introduction of auxiliary electromagnetic fields
US10197389B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 2016 |
| Grant date | Feb 5, 2019 |
| Priority date | — |
| Expiry date | Aug 29, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Metrology measurement methods and tools are provided, which illuminate a stationary diffractive target by a stationary illumination source, measure a signal composed of a sum of a zeroth order diffraction signal and a first order diffraction signal, repeat the measuring for a plurality of relations between the zeroth and the first diffraction signals, while maintaining the diffractive target and the illumination source stationary, and derive the first order diffraction signal from the measured sums. Illumination may be coherent and measurements may be in the pupil plane, or illumination may be incoherent and measurements may be in the field plane, in either case, partial overlapping of the zeroth and the first diffraction orders are measured. Illumination may be annular and the diffractive target may be a one cell SCOL target with periodic structures having different pitches to separate the overlap regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.