Patent · US Active

Diffraction based overlay linearity testing

US9239523B2 · kind B2 · utility

2Cited by

3References

20Claims

0Family size

Assignee

Nanometrics Incorporated · US

Inventors

Jie Li · Lo Wu, CN
Zhuan Liu · Fremont, US
Silvio J. Rabello · Palo Alto, US
Nigel P. Smith · Hsinchu, TW

Key dates

Filing date	Mar 22, 2011
Grant date	Jan 19, 2016
Priority date	—
Expiry date	Jul 21, 2032

Classification

Technology area (CPC G)Physics
CPC primaryG03F7/70633
WIPO fieldOptics
WIPO sectorInstruments

Abstract

An empirical diffraction based overlay (eDBO) measurement of an overlay error is produced using diffraction signals from a plurality of diffraction based alignment pads from an alignment target. The linearity of the overlay error is tested using the same diffraction signals or a different set of diffraction signals from diffraction based alignment pads. Wavelengths that do not have a linear response to overlay error may be excluded from the measurement error.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.