Scatterometry method with characteristic signatures matching
US7532317B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Dec 28, 2005 |
| Grant date | May 12, 2009 |
| Priority date | — |
| Expiry date | Dec 23, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system and method for efficiently and accurately determining grating profiles uses characteristic signature matching in a discrepancy enhanced library generation process. Using light scattering theory, a series of scattering signatures vs. scattering angles or wavelengths are generated based on the designed grating parameters, for example. CD, thickness and Line:Space ratio. This method selects characteristic portions of the signatures wherever their discrepancy exceeds the preset criteria and reforms a characteristic signature library for quick and accurate matching. A rigorous coupled wave theory can be used to generate a diffraction library including a plurality of simulated diffraction spectrums based on a predetermined structural parameter of the grating. The characteristic region of the plurality of simulated diffraction spectrums is determined based on if the root mean square error of the plurality of simulated diffraction spectrums is larger than a noise level of a measuring machine. The diffraction intensity of the measured diffraction spectrum is compared with that of the plurality of simulated diffraction spectrums in the characteristic region to select a match spectru…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.