Scatterometry based methods and systems for measurement of strain in semiconductor structures
US11060846B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 2019 |
| Grant date | Jul 13, 2021 |
| Priority date | — |
| Expiry date | Oct 22, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8848
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and systems for measuring optical properties of transistor channel structures and linking the optical properties to the state of strain are presented herein. Optical scatterometry measurements of strain are performed on metrology targets that closely mimic partially manufactured, real device structures. In one aspect, optical scatterometry is employed to measure uniaxial strain in a semiconductor channel based on differences in measured spectra along and across the semiconductor channel. In a further aspect, the effect of strain on measured spectra is decorrelated from other contributors, such as the geometry and material properties of structures captured in the measurement. In another aspect, measurements are performed on a metrology target pair including a strained metrology target and a corresponding unstrained metrology target to resolve the geometry of the metrology target under measurement and to provide a reference for the estimation of the absolute value of strain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.