Optical system and method for measuring in patterned structures
US9140544B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2012 |
| Grant date | Sep 22, 2015 |
| Priority date | — |
| Expiry date | Sep 19, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical system is presented for use in measuring in patterned structures having vias. The optical system comprises an illumination channel for propagating illuminated light onto the structure being measured; a detection channel for collecting light returned from the illuminated structure to a detection unit; and an attenuation assembly accommodated in the illumination and detection channels and being configured and operable for selectively attenuating light propagating along the detection channel, the attenuation creating a predetermined condition for the selectively attenuated light, said predetermined condition being defined by a predetermined ratio between a first light portion corresponding to a dark field condition and a second light portion corresponding to a bright field condition in said selectively attenuated light, detected selectively attenuated light being therefore indicative of at least one parameter of the via being illuminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.