Focus metrology and targets which utilize transformations based on aerial images of the targets
US10197922B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 2016 |
| Grant date | Feb 5, 2019 |
| Priority date | — |
| Expiry date | Oct 28, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70641
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Focus metrology methods and modules are provided, which use aerial-images-based transformations to share measurement information derived from multiple targets and/or to design additional targets to specified compliant targets, which enable simple adjustment of focus targets to changing production conditions. Methods comprise positioning two or more focus targets in each wafer field, conducting focus measurements of the targets, transforming the focus measurements into a single set of results for each field, using a transformation between the targets that is based on the aerial images thereof, and deriving focus results from the single sets of results; and possibly designing the focus targets from specified targets using aerial image parameters of the specified targets.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.