System and method for measuring and analyzing lithographic parameters and determining optimal process corrections
US7749666B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 2006 |
| Grant date | Jul 6, 2010 |
| Priority date | — |
| Expiry date | Feb 21, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70641
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of using an in-situ aerial image sensor array is disclosed to separate and remove the focal plane variations caused by the image sensor array non-flatness and/or by the exposure tool by collecting sensor image data at various nominal focal planes and by determining best focus at each sampling location by analysis of the through-focus data. In various embodiments, the method provides accurate image data at best focus anywhere in the exposure field, image data covering an exposure-dose based process window area, and a map of effective focal plane distortions. The focus map can be separated into contributions from the exposure tool and contributions due to topography of the image sensor array by suitable calibration or self-calibration procedures. The basic method enables a wide range of applications, including for example qualification testing, process monitoring, and process control by deriving optimum process corrections from analysis of the image sensor data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.