Method and apparatus for determining lithographic quality of a structure
US9518936B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 2013 |
| Grant date | Dec 13, 2016 |
| Priority date | — |
| Expiry date | Oct 30, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method for determining lithographic quality of a structure produced by a lithographic process using a periodic pattern, such as a grating, detects lithographic process window edges and optimum process conditions. Method steps are: 602: printing a structure using a lithographic process using a grating pattern; 604: selecting a first characteristic, such as a polarization direction, for the illumination; 606: illuminating the structure with incident radiation with first characteristic 608: detecting scattered radiation; 610: selecting a second characteristic, such as a different polarization direction, for the illumination; 612: illuminating the structure with incident radiation with the second characteristic; 614: detecting scattered radiation; 616: rotating one or more angularly resolved spectrum to line up the polarizations, thus correcting for different orientations of the polarizations; 618: determining a difference between the measured angularly resolved spectra; and 620: determining a value of lithographic quality of the structure using the determined difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.